text: /*
   *	IPv6 Address [auto]configuration
   *	Linux INET6 implementation
   *
   *	Authors:
   *	Pedro Roque		<roque@di.fc.ul.pt>
   *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
   *
   *	This program is free software; you can redistribute it and/or
   *      modify it under the terms of the GNU General Public License
   *      as published by the Free Software Foundation; either version
   *      2 of the License, or (at your option) any later version.
   */
  
  /*
   *	Changes:
   *
   *	Janos Farkas			:	delete timer on ifdown
   *	<chexum@bankinf.banki.hu>
   *	Andi Kleen			:	kill double kfree on module
   *						unload.
   *	Maciej W. Rozycki		:	FDDI support
   *	sekiya@USAGI			:	Don't send too many RS
   *						packets.
   *	yoshfuji@USAGI			:       Fixed interval between DAD
   *						packets.
   *	YOSHIFUJI Hideaki @USAGI	:	improved accuracy of
   *						address validation timer.
   *	YOSHIFUJI Hideaki @USAGI	:	Privacy Extensions (RFC3041)
   *						support.
   *	Yuji SEKIYA @USAGI		:	Don't assign a same IPv6
   *						address on a same interface.
   *	YOSHIFUJI Hideaki @USAGI	:	ARCnet support
   *	YOSHIFUJI Hideaki @USAGI	:	convert /proc/net/if_inet6 to
   *						seq_file.
   *	YOSHIFUJI Hideaki @USAGI	:	improved source address
   *						selection; consider scope,
   *						status etc.
   */
  
  #define pr_fmt(fmt) "IPv6: " fmt
  
  #include <linux/errno.h>
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/sched/signal.h>
  #include <linux/socket.h>
  #include <linux/sockios.h>
  #include <linux/net.h>
  #include <linux/inet.h>
  #include <linux/in6.h>
  #include <linux/netdevice.h>
  #include <linux/if_addr.h>
  #include <linux/if_arp.h>
  #include <linux/if_arcnet.h>
  #include <linux/if_infiniband.h>
  #include <linux/route.h>
  #include <linux/inetdevice.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #ifdef CONFIG_SYSCTL
  #include <linux/sysctl.h>
  #endif
  #include <linux/capability.h>
  #include <linux/delay.h>
  #include <linux/notifier.h>
  #include <linux/string.h>
  #include <linux/hash.h>
  
  #include <net/net_namespace.h>
  #include <net/sock.h>
  #include <net/snmp.h>
  
  #include <net/6lowpan.h>
  #include <net/firewire.h>
  #include <net/ipv6.h>
  #include <net/protocol.h>
  #include <net/ndisc.h>
  #include <net/ip6_route.h>
  #include <net/addrconf.h>
  #include <net/tcp.h>
  #include <net/ip.h>
  #include <net/netlink.h>
  #include <net/pkt_sched.h>
  #include <net/l3mdev.h>
  #include <linux/if_tunnel.h>
  #include <linux/rtnetlink.h>
  #include <linux/netconf.h>
  #include <linux/random.h>
  #include <linux/uaccess.h>
  #include <asm/unaligned.h>
  
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/export.h>
  
  /* Set to 3 to get tracing... */
  #define ACONF_DEBUG 2
  
  #if ACONF_DEBUG >= 3
  #define ADBG(fmt, ...) printk(fmt, ##__VA_ARGS__)
  #else
  #define ADBG(fmt, ...) do { if (0) printk(fmt, ##__VA_ARGS__); } while (0)
  #endif
  
  #define	INFINITY_LIFE_TIME	0xFFFFFFFF
  
  #define IPV6_MAX_STRLEN \
  	sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")
  
  static inline u32 cstamp_delta(unsigned long cstamp)
  {
  	return (cstamp - INITIAL_JIFFIES) * 100UL / HZ;
  }
  
  static inline s32 rfc3315_s14_backoff_init(s32 irt)
  {
  	/* multiply 'initial retransmission time' by 0.9 .. 1.1 */
  	u64 tmp = (900000 + prandom_u32() % 200001) * (u64)irt;
  	do_div(tmp, 1000000);
  	return (s32)tmp;
  }
  
  static inline s32 rfc3315_s14_backoff_update(s32 rt, s32 mrt)
  {
  	/* multiply 'retransmission timeout' by 1.9 .. 2.1 */
  	u64 tmp = (1900000 + prandom_u32() % 200001) * (u64)rt;
  	do_div(tmp, 1000000);
  	if ((s32)tmp > mrt) {
  		/* multiply 'maximum retransmission time' by 0.9 .. 1.1 */
  		tmp = (900000 + prandom_u32() % 200001) * (u64)mrt;
  		do_div(tmp, 1000000);
  	}
  	return (s32)tmp;
  }
  
  #ifdef CONFIG_SYSCTL
  static int addrconf_sysctl_register(struct inet6_dev *idev);
  static void addrconf_sysctl_unregister(struct inet6_dev *idev);
  #else
  static inline int addrconf_sysctl_register(struct inet6_dev *idev)
  {
  	return 0;
  }
  
  static inline void addrconf_sysctl_unregister(struct inet6_dev *idev)
  {
  }
  #endif
  
  static void ipv6_regen_rndid(struct inet6_dev *idev);
  static void ipv6_try_regen_rndid(struct inet6_dev *idev, struct in6_addr *tmpaddr);
  
  static int ipv6_generate_eui64(u8 *eui, struct net_device *dev);
  static int ipv6_count_addresses(struct inet6_dev *idev);
  static int ipv6_generate_stable_address(struct in6_addr *addr,
  					u8 dad_count,
  					const struct inet6_dev *idev);
  
  /*
   *	Configured unicast address hash table
   */
  static struct hlist_head inet6_addr_lst[IN6_ADDR_HSIZE];
  static DEFINE_SPINLOCK(addrconf_hash_lock);
  
  static void addrconf_verify(void);
  static void addrconf_verify_rtnl(void);
  static void addrconf_verify_work(struct work_struct *);
  
  static struct workqueue_struct *addrconf_wq;
  static DECLARE_DELAYED_WORK(addr_chk_work, addrconf_verify_work);
  
  static void addrconf_join_anycast(struct inet6_ifaddr *ifp);
  static void addrconf_leave_anycast(struct inet6_ifaddr *ifp);
  
  static void addrconf_type_change(struct net_device *dev,
  				 unsigned long event);
  static int addrconf_ifdown(struct net_device *dev, int how);
  
  static struct rt6_info *addrconf_get_prefix_route(const struct in6_addr *pfx,
  						  int plen,
  						  const struct net_device *dev,
  						  u32 flags, u32 noflags);
  
  static void addrconf_dad_start(struct inet6_ifaddr *ifp);
  static void addrconf_dad_work(struct work_struct *w);
  static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id,
  				   bool send_na);
  static void addrconf_dad_run(struct inet6_dev *idev);
  static void addrconf_rs_timer(unsigned long data);
  static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifa);
  static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifa);
  
  static void inet6_prefix_notify(int event, struct inet6_dev *idev,
  				struct prefix_info *pinfo);
  static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
  			       struct net_device *dev);
  
  static struct ipv6_devconf ipv6_devconf __read_mostly = {
  	.forwarding		= 0,
  	.hop_limit		= IPV6_DEFAULT_HOPLIMIT,
  	.mtu6			= IPV6_MIN_MTU,
  	.accept_ra		= 1,
  	.accept_redirects	= 1,
  	.autoconf		= 1,
  	.force_mld_version	= 0,
  	.mldv1_unsolicited_report_interval = 10 * HZ,
  	.mldv2_unsolicited_report_interval = HZ,
  	.dad_transmits		= 1,
  	.rtr_solicits		= MAX_RTR_SOLICITATIONS,
  	.rtr_solicit_interval	= RTR_SOLICITATION_INTERVAL,
  	.rtr_solicit_max_interval = RTR_SOLICITATION_MAX_INTERVAL,
  	.rtr_solicit_delay	= MAX_RTR_SOLICITATION_DELAY,
  	.use_tempaddr		= 0,
  	.temp_valid_lft		= TEMP_VALID_LIFETIME,
  	.temp_prefered_lft	= TEMP_PREFERRED_LIFETIME,
  	.regen_max_retry	= REGEN_MAX_RETRY,
  	.max_desync_factor	= MAX_DESYNC_FACTOR,
  	.max_addresses		= IPV6_MAX_ADDRESSES,
  	.accept_ra_defrtr	= 1,
  	.accept_ra_from_local	= 0,
  	.accept_ra_min_hop_limit= 1,
  	.accept_ra_pinfo	= 1,
  #ifdef CONFIG_IPV6_ROUTER_PREF
  	.accept_ra_rtr_pref	= 1,
  	.rtr_probe_interval	= 60 * HZ,
  #ifdef CONFIG_IPV6_ROUTE_INFO
  	.accept_ra_rt_info_min_plen = 0,
  	.accept_ra_rt_info_max_plen = 0,
  #endif
  #endif
  	.proxy_ndp		= 0,
  	.accept_source_route	= 0,	/* we do not accept RH0 by default. */
  	.disable_ipv6		= 0,
  	.accept_dad		= 0,
  	.suppress_frag_ndisc	= 1,
  	.accept_ra_mtu		= 1,
  	.stable_secret		= {
  		.initialized = false,
  	},
  	.use_oif_addrs_only	= 0,
  	.ignore_routes_with_linkdown = 0,
  	.keep_addr_on_down	= 0,
  	.seg6_enabled		= 0,
  #ifdef CONFIG_IPV6_SEG6_HMAC
  	.seg6_require_hmac	= 0,
  #endif
  	.enhanced_dad           = 1,
  	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
  	.disable_policy		= 0,
  };
  
  static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
  	.forwarding		= 0,
  	.hop_limit		= IPV6_DEFAULT_HOPLIMIT,
  	.mtu6			= IPV6_MIN_MTU,
  	.accept_ra		= 1,
  	.accept_redirects	= 1,
  	.autoconf		= 1,
  	.force_mld_version	= 0,
  	.mldv1_unsolicited_report_interval = 10 * HZ,
  	.mldv2_unsolicited_report_interval = HZ,
  	.dad_transmits		= 1,
  	.rtr_solicits		= MAX_RTR_SOLICITATIONS,
  	.rtr_solicit_interval	= RTR_SOLICITATION_INTERVAL,
  	.rtr_solicit_max_interval = RTR_SOLICITATION_MAX_INTERVAL,
  	.rtr_solicit_delay	= MAX_RTR_SOLICITATION_DELAY,
  	.use_tempaddr		= 0,
  	.temp_valid_lft		= TEMP_VALID_LIFETIME,
  	.temp_prefered_lft	= TEMP_PREFERRED_LIFETIME,
  	.regen_max_retry	= REGEN_MAX_RETRY,
  	.max_desync_factor	= MAX_DESYNC_FACTOR,
  	.max_addresses		= IPV6_MAX_ADDRESSES,
  	.accept_ra_defrtr	= 1,
  	.accept_ra_from_local	= 0,
  	.accept_ra_min_hop_limit= 1,
  	.accept_ra_pinfo	= 1,
  #ifdef CONFIG_IPV6_ROUTER_PREF
  	.accept_ra_rtr_pref	= 1,
  	.rtr_probe_interval	= 60 * HZ,
  #ifdef CONFIG_IPV6_ROUTE_INFO
  	.accept_ra_rt_info_min_plen = 0,
  	.accept_ra_rt_info_max_plen = 0,
  #endif
  #endif
  	.proxy_ndp		= 0,
  	.accept_source_route	= 0,	/* we do not accept RH0 by default. */
  	.disable_ipv6		= 0,
  	.accept_dad		= 1,
  	.suppress_frag_ndisc	= 1,
  	.accept_ra_mtu		= 1,
  	.stable_secret		= {
  		.initialized = false,
  	},
  	.use_oif_addrs_only	= 0,
  	.ignore_routes_with_linkdown = 0,
  	.keep_addr_on_down	= 0,
  	.seg6_enabled		= 0,
  #ifdef CONFIG_IPV6_SEG6_HMAC
  	.seg6_require_hmac	= 0,
  #endif
  	.enhanced_dad           = 1,
  	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
  	.disable_policy		= 0,
  };
  
  /* Check if link is ready: is it up and is a valid qdisc available */
  static inline bool addrconf_link_ready(const struct net_device *dev)
  {
  	return netif_oper_up(dev) && !qdisc_tx_is_noop(dev);
  }
  
  static void addrconf_del_rs_timer(struct inet6_dev *idev)
  {
  	if (del_timer(&idev->rs_timer))
  		__in6_dev_put(idev);
  }
  
  static void addrconf_del_dad_work(struct inet6_ifaddr *ifp)
  {
  	if (cancel_delayed_work(&ifp->dad_work))
  		__in6_ifa_put(ifp);
  }
  
  static void addrconf_mod_rs_timer(struct inet6_dev *idev,
  				  unsigned long when)
  {
  	if (!timer_pending(&idev->rs_timer))
  		in6_dev_hold(idev);
  	mod_timer(&idev->rs_timer, jiffies + when);
  }
  
  static void addrconf_mod_dad_work(struct inet6_ifaddr *ifp,
  				   unsigned long delay)
  {
  	in6_ifa_hold(ifp);
  	if (mod_delayed_work(addrconf_wq, &ifp->dad_work, delay))
  		in6_ifa_put(ifp);
  }
  
  static int snmp6_alloc_dev(struct inet6_dev *idev)
  {
  	int i;
  
  	idev->stats.ipv6 = alloc_percpu(struct ipstats_mib);
  	if (!idev->stats.ipv6)
  		goto err_ip;
  
  	for_each_possible_cpu(i) {
  		struct ipstats_mib *addrconf_stats;
  		addrconf_stats = per_cpu_ptr(idev->stats.ipv6, i);
  		u64_stats_init(&addrconf_stats->syncp);
  	}
  
  
  	idev->stats.icmpv6dev = kzalloc(sizeof(struct icmpv6_mib_device),
  					GFP_KERNEL);
  	if (!idev->stats.icmpv6dev)
  		goto err_icmp;
  	idev->stats.icmpv6msgdev = kzalloc(sizeof(struct icmpv6msg_mib_device),
  					   GFP_KERNEL);
  	if (!idev->stats.icmpv6msgdev)
  		goto err_icmpmsg;
  
  	return 0;
  
  err_icmpmsg:
  	kfree(idev->stats.icmpv6dev);
  err_icmp:
  	free_percpu(idev->stats.ipv6);
  err_ip:
  	return -ENOMEM;
  }
  
  static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
  {
  	struct inet6_dev *ndev;
  	int err = -ENOMEM;
  
  	ASSERT_RTNL();
  
  	if (dev->mtu < IPV6_MIN_MTU)
  		return ERR_PTR(-EINVAL);
  
  	ndev = kzalloc(sizeof(struct inet6_dev), GFP_KERNEL);
  	if (!ndev)
  		return ERR_PTR(err);
  
  	rwlock_init(&ndev->lock);
  	ndev->dev = dev;
  	INIT_LIST_HEAD(&ndev->addr_list);
  	setup_timer(&ndev->rs_timer, addrconf_rs_timer,
  		    (unsigned long)ndev);
  	memcpy(&ndev->cnf, dev_net(dev)->ipv6.devconf_dflt, sizeof(ndev->cnf));
  
  	if (ndev->cnf.stable_secret.initialized)
  		ndev->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
  	else
  		ndev->cnf.addr_gen_mode = ipv6_devconf_dflt.addr_gen_mode;
  
  	ndev->cnf.mtu6 = dev->mtu;
  	ndev->nd_parms = neigh_parms_alloc(dev, &nd_tbl);
  	if (!ndev->nd_parms) {
  		kfree(ndev);
  		return ERR_PTR(err);
  	}
  	if (ndev->cnf.forwarding)
  		dev_disable_lro(dev);
  	/* We refer to the device */
  	dev_hold(dev);
  
  	if (snmp6_alloc_dev(ndev) < 0) {
  		ADBG(KERN_WARNING
  			"%s: cannot allocate memory for statistics; dev=%s.\n",
  			__func__, dev->name);
  		neigh_parms_release(&nd_tbl, ndev->nd_parms);
  		dev_put(dev);
  		kfree(ndev);
  		return ERR_PTR(err);
  	}
  
  	if (snmp6_register_dev(ndev) < 0) {
  		ADBG(KERN_WARNING
  			"%s: cannot create /proc/net/dev_snmp6/%s\n",
  			__func__, dev->name);
  		goto err_release;
  	}
  
  	/* One reference from device. */
  	refcount_set(&ndev->refcnt, 1);
  
  	if (dev->flags & (IFF_NOARP | IFF_LOOPBACK))
  		ndev->cnf.accept_dad = -1;
  
  #if IS_ENABLED(CONFIG_IPV6_SIT)
  	if (dev->type == ARPHRD_SIT && (dev->priv_flags & IFF_ISATAP)) {
  		pr_info("%s: Disabled Multicast RS\n", dev->name);
  		ndev->cnf.rtr_solicits = 0;
  	}
  #endif
  
  	INIT_LIST_HEAD(&ndev->tempaddr_list);
  	ndev->desync_factor = U32_MAX;
  	if ((dev->flags&IFF_LOOPBACK) ||
  	    dev->type == ARPHRD_TUNNEL ||
  	    dev->type == ARPHRD_TUNNEL6 ||
  	    dev->type == ARPHRD_SIT ||
  	    dev->type == ARPHRD_NONE) {
  		ndev->cnf.use_tempaddr = -1;
  	} else
  		ipv6_regen_rndid(ndev);
  
  	ndev->token = in6addr_any;
  
  	if (netif_running(dev) && addrconf_link_ready(dev))
  		ndev->if_flags |= IF_READY;
  
  	ipv6_mc_init_dev(ndev);
  	ndev->tstamp = jiffies;
  	err = addrconf_sysctl_register(ndev);
  	if (err) {
  		ipv6_mc_destroy_dev(ndev);
  		snmp6_unregister_dev(ndev);
  		goto err_release;
  	}
  	/* protected by rtnl_lock */
  	rcu_assign_pointer(dev->ip6_ptr, ndev);
  
  	/* Join interface-local all-node multicast group */
  	ipv6_dev_mc_inc(dev, &in6addr_interfacelocal_allnodes);
  
  	/* Join all-node multicast group */
  	ipv6_dev_mc_inc(dev, &in6addr_linklocal_allnodes);
  
  	/* Join all-router multicast group if forwarding is set */
  	if (ndev->cnf.forwarding && (dev->flags & IFF_MULTICAST))
  		ipv6_dev_mc_inc(dev, &in6addr_linklocal_allrouters);
  
  	return ndev;
  
  err_release:
  	neigh_parms_release(&nd_tbl, ndev->nd_parms);
  	ndev->dead = 1;
  	in6_dev_finish_destroy(ndev);
  	return ERR_PTR(err);
  }
  
  static struct inet6_dev *ipv6_find_idev(struct net_device *dev)
  {
  	struct inet6_dev *idev;
  
  	ASSERT_RTNL();
  
  	idev = __in6_dev_get(dev);
  	if (!idev) {
  		idev = ipv6_add_dev(dev);
  		if (IS_ERR(idev))
  			return NULL;
  	}
  
  	if (dev->flags&IFF_UP)
  		ipv6_mc_up(idev);
  	return idev;
  }
  
  static int inet6_netconf_msgsize_devconf(int type)
  {
  	int size =  NLMSG_ALIGN(sizeof(struct netconfmsg))
  		    + nla_total_size(4);	/* NETCONFA_IFINDEX */
  	bool all = false;
  
  	if (type == NETCONFA_ALL)
  		all = true;
  
  	if (all || type == NETCONFA_FORWARDING)
  		size += nla_total_size(4);
  #ifdef CONFIG_IPV6_MROUTE
  	if (all || type == NETCONFA_MC_FORWARDING)
  		size += nla_total_size(4);
  #endif
  	if (all || type == NETCONFA_PROXY_NEIGH)
  		size += nla_total_size(4);
  
  	if (all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN)
  		size += nla_total_size(4);
  
  	return size;
  }
  
  static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
  				      struct ipv6_devconf *devconf, u32 portid,
  				      u32 seq, int event, unsigned int flags,
  				      int type)
  {
  	struct nlmsghdr  *nlh;
  	struct netconfmsg *ncm;
  	bool all = false;
  
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct netconfmsg),
  			flags);
  	if (!nlh)
  		return -EMSGSIZE;
  
  	if (type == NETCONFA_ALL)
  		all = true;
  
  	ncm = nlmsg_data(nlh);
  	ncm->ncm_family = AF_INET6;
  
  	if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
  		goto nla_put_failure;
  
  	if (!devconf)
  		goto out;
  
  	if ((all || type == NETCONFA_FORWARDING) &&
  	    nla_put_s32(skb, NETCONFA_FORWARDING, devconf->forwarding) < 0)
  		goto nla_put_failure;
  #ifdef CONFIG_IPV6_MROUTE
  	if ((all || type == NETCONFA_MC_FORWARDING) &&
  	    nla_put_s32(skb, NETCONFA_MC_FORWARDING,
  			devconf->mc_forwarding) < 0)
  		goto nla_put_failure;
  #endif
  	if ((all || type == NETCONFA_PROXY_NEIGH) &&
  	    nla_put_s32(skb, NETCONFA_PROXY_NEIGH, devconf->proxy_ndp) < 0)
  		goto nla_put_failure;
  
  	if ((all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) &&
  	    nla_put_s32(skb, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
  			devconf->ignore_routes_with_linkdown) < 0)
  		goto nla_put_failure;
  
  out:
  	nlmsg_end(skb, nlh);
  	return 0;
  
  nla_put_failure:
  	nlmsg_cancel(skb, nlh);
  	return -EMSGSIZE;
  }
  
  void inet6_netconf_notify_devconf(struct net *net, int event, int type,
  				  int ifindex, struct ipv6_devconf *devconf)
  {
  	struct sk_buff *skb;
  	int err = -ENOBUFS;
  
  	skb = nlmsg_new(inet6_netconf_msgsize_devconf(type), GFP_KERNEL);
  	if (!skb)
  		goto errout;
  
  	err = inet6_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
  					 event, 0, type);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout;
  	}
  	rtnl_notify(skb, net, 0, RTNLGRP_IPV6_NETCONF, NULL, GFP_KERNEL);
  	return;
  errout:
  	rtnl_set_sk_err(net, RTNLGRP_IPV6_NETCONF, err);
  }
  
  static const struct nla_policy devconf_ipv6_policy[NETCONFA_MAX+1] = {
  	[NETCONFA_IFINDEX]	= { .len = sizeof(int) },
  	[NETCONFA_FORWARDING]	= { .len = sizeof(int) },
  	[NETCONFA_PROXY_NEIGH]	= { .len = sizeof(int) },
  	[NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN]	= { .len = sizeof(int) },
  };
  
  static int inet6_netconf_get_devconf(struct sk_buff *in_skb,
  				     struct nlmsghdr *nlh,
  				     struct netlink_ext_ack *extack)
  {
  	struct net *net = sock_net(in_skb->sk);
  	struct nlattr *tb[NETCONFA_MAX+1];
  	struct netconfmsg *ncm;
  	struct sk_buff *skb;
  	struct ipv6_devconf *devconf;
  	struct inet6_dev *in6_dev;
  	struct net_device *dev;
  	int ifindex;
  	int err;
  
  	err = nlmsg_parse(nlh, sizeof(*ncm), tb, NETCONFA_MAX,
  			  devconf_ipv6_policy, extack);
  	if (err < 0)
  		goto errout;
  
  	err = -EINVAL;
  	if (!tb[NETCONFA_IFINDEX])
  		goto errout;
  
  	ifindex = nla_get_s32(tb[NETCONFA_IFINDEX]);
  	switch (ifindex) {
  	case NETCONFA_IFINDEX_ALL:
  		devconf = net->ipv6.devconf_all;
  		break;
  	case NETCONFA_IFINDEX_DEFAULT:
  		devconf = net->ipv6.devconf_dflt;
  		break;
  	default:
  		dev = __dev_get_by_index(net, ifindex);
  		if (!dev)
  			goto errout;
  		in6_dev = __in6_dev_get(dev);
  		if (!in6_dev)
  			goto errout;
  		devconf = &in6_dev->cnf;
  		break;
  	}
  
  	err = -ENOBUFS;
  	skb = nlmsg_new(inet6_netconf_msgsize_devconf(NETCONFA_ALL), GFP_ATOMIC);
  	if (!skb)
  		goto errout;
  
  	err = inet6_netconf_fill_devconf(skb, ifindex, devconf,
  					 NETLINK_CB(in_skb).portid,
  					 nlh->nlmsg_seq, RTM_NEWNETCONF, 0,
  					 NETCONFA_ALL);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout;
  	}
  	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
  errout:
  	return err;
  }
  
  static int inet6_netconf_dump_devconf(struct sk_buff *skb,
  				      struct netlink_callback *cb)
  {
  	struct net *net = sock_net(skb->sk);
  	int h, s_h;
  	int idx, s_idx;
  	struct net_device *dev;
  	struct inet6_dev *idev;
  	struct hlist_head *head;
  
  	s_h = cb->args[0];
  	s_idx = idx = cb->args[1];
  
  	for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
  		idx = 0;
  		head = &net->dev_index_head[h];
  		rcu_read_lock();
  		cb->seq = atomic_read(&net->ipv6.dev_addr_genid) ^
  			  net->dev_base_seq;
  		hlist_for_each_entry_rcu(dev, head, index_hlist) {
  			if (idx < s_idx)
  				goto cont;
  			idev = __in6_dev_get(dev);
  			if (!idev)
  				goto cont;
  
  			if (inet6_netconf_fill_devconf(skb, dev->ifindex,
  						       &idev->cnf,
  						       NETLINK_CB(cb->skb).portid,
  						       cb->nlh->nlmsg_seq,
  						       RTM_NEWNETCONF,
  						       NLM_F_MULTI,
  						       NETCONFA_ALL) < 0) {
  				rcu_read_unlock();
  				goto done;
  			}
  			nl_dump_check_consistent(cb, nlmsg_hdr(skb));
  cont:
  			idx++;
  		}
  		rcu_read_unlock();
  	}
  	if (h == NETDEV_HASHENTRIES) {
  		if (inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,
  					       net->ipv6.devconf_all,
  					       NETLINK_CB(cb->skb).portid,
  					       cb->nlh->nlmsg_seq,
  					       RTM_NEWNETCONF, NLM_F_MULTI,
  					       NETCONFA_ALL) < 0)
  			goto done;
  		else
  			h++;
  	}
  	if (h == NETDEV_HASHENTRIES + 1) {
  		if (inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,
  					       net->ipv6.devconf_dflt,
  					       NETLINK_CB(cb->skb).portid,
  					       cb->nlh->nlmsg_seq,
  					       RTM_NEWNETCONF, NLM_F_MULTI,
  					       NETCONFA_ALL) < 0)
  			goto done;
  		else
  			h++;
  	}
  done:
  	cb->args[0] = h;
  	cb->args[1] = idx;
  
  	return skb->len;
  }
  
  #ifdef CONFIG_SYSCTL
  static void dev_forward_change(struct inet6_dev *idev)
  {
  	struct net_device *dev;
  	struct inet6_ifaddr *ifa;
  
  	if (!idev)
  		return;
  	dev = idev->dev;
  	if (idev->cnf.forwarding)
  		dev_disable_lro(dev);
  	if (dev->flags & IFF_MULTICAST) {
  		if (idev->cnf.forwarding) {
  			ipv6_dev_mc_inc(dev, &in6addr_linklocal_allrouters);
  			ipv6_dev_mc_inc(dev, &in6addr_interfacelocal_allrouters);
  			ipv6_dev_mc_inc(dev, &in6addr_sitelocal_allrouters);
  		} else {
  			ipv6_dev_mc_dec(dev, &in6addr_linklocal_allrouters);
  			ipv6_dev_mc_dec(dev, &in6addr_interfacelocal_allrouters);
  			ipv6_dev_mc_dec(dev, &in6addr_sitelocal_allrouters);
  		}
  	}
  
  	list_for_each_entry(ifa, &idev->addr_list, if_list) {
  		if (ifa->flags&IFA_F_TENTATIVE)
  			continue;
  		if (idev->cnf.forwarding)
  			addrconf_join_anycast(ifa);
  		else
  			addrconf_leave_anycast(ifa);
  	}
  	inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF,
  				     NETCONFA_FORWARDING,
  				     dev->ifindex, &idev->cnf);
  }
  
  
  static void addrconf_forward_change(struct net *net, __s32 newf)
  {
  	struct net_device *dev;
  	struct inet6_dev *idev;
  
  	for_each_netdev(net, dev) {
  		idev = __in6_dev_get(dev);
  		if (idev) {
  			int changed = (!idev->cnf.forwarding) ^ (!newf);
  			idev->cnf.forwarding = newf;
  			if (changed)
  				dev_forward_change(idev);
  		}
  	}
  }
  
  static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int newf)
  {
  	struct net *net;
  	int old;
  
  	if (!rtnl_trylock())
  		return restart_syscall();
  
  	net = (struct net *)table->extra2;
  	old = *p;
  	*p = newf;
  
  	if (p == &net->ipv6.devconf_dflt->forwarding) {
  		if ((!newf) ^ (!old))
  			inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
  						     NETCONFA_FORWARDING,
  						     NETCONFA_IFINDEX_DEFAULT,
  						     net->ipv6.devconf_dflt);
  		rtnl_unlock();
  		return 0;
  	}
  
  	if (p == &net->ipv6.devconf_all->forwarding) {
  		int old_dflt = net->ipv6.devconf_dflt->forwarding;
  
  		net->ipv6.devconf_dflt->forwarding = newf;
  		if ((!newf) ^ (!old_dflt))
  			inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
  						     NETCONFA_FORWARDING,
  						     NETCONFA_IFINDEX_DEFAULT,
  						     net->ipv6.devconf_dflt);
  
  		addrconf_forward_change(net, newf);
  		if ((!newf) ^ (!old))
  			inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
  						     NETCONFA_FORWARDING,
  						     NETCONFA_IFINDEX_ALL,
  						     net->ipv6.devconf_all);
  	} else if ((!newf) ^ (!old))
  		dev_forward_change((struct inet6_dev *)table->extra1);
  	rtnl_unlock();
  
  	if (newf)
  		rt6_purge_dflt_routers(net);
  	return 1;
  }
  
  static void addrconf_linkdown_change(struct net *net, __s32 newf)
  {
  	struct net_device *dev;
  	struct inet6_dev *idev;
  
  	for_each_netdev(net, dev) {
  		idev = __in6_dev_get(dev);
  		if (idev) {
  			int changed = (!idev->cnf.ignore_routes_with_linkdown) ^ (!newf);
  
  			idev->cnf.ignore_routes_with_linkdown = newf;
  			if (changed)
  				inet6_netconf_notify_devconf(dev_net(dev),
  							     RTM_NEWNETCONF,
  							     NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
  							     dev->ifindex,
  							     &idev->cnf);
  		}
  	}
  }
  
  static int addrconf_fixup_linkdown(struct ctl_table *table, int *p, int newf)
  {
  	struct net *net;
  	int old;
  
  	if (!rtnl_trylock())
  		return restart_syscall();
  
  	net = (struct net *)table->extra2;
  	old = *p;
  	*p = newf;
  
  	if (p == &net->ipv6.devconf_dflt->ignore_routes_with_linkdown) {
  		if ((!newf) ^ (!old))
  			inet6_netconf_notify_devconf(net,
  						     RTM_NEWNETCONF,
  						     NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
  						     NETCONFA_IFINDEX_DEFAULT,
  						     net->ipv6.devconf_dflt);
  		rtnl_unlock();
  		return 0;
  	}
  
  	if (p == &net->ipv6.devconf_all->ignore_routes_with_linkdown) {
  		net->ipv6.devconf_dflt->ignore_routes_with_linkdown = newf;
  		addrconf_linkdown_change(net, newf);
  		if ((!newf) ^ (!old))
  			inet6_netconf_notify_devconf(net,
  						     RTM_NEWNETCONF,
  						     NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
  						     NETCONFA_IFINDEX_ALL,
  						     net->ipv6.devconf_all);
  	}
  	rtnl_unlock();
  
  	return 1;
  }
  
  #endif
  
  /* Nobody refers to this ifaddr, destroy it */
  void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp)
  {
  	WARN_ON(!hlist_unhashed(&ifp->addr_lst));
  
  #ifdef NET_REFCNT_DEBUG
  	pr_debug("%s\n", __func__);
  #endif
  
  	in6_dev_put(ifp->idev);
  
  	if (cancel_delayed_work(&ifp->dad_work))
  		pr_notice("delayed DAD work was pending while freeing ifa=%p\n",
  			  ifp);
  
  	if (ifp->state != INET6_IFADDR_STATE_DEAD) {
  		pr_warn("Freeing alive inet6 address %p\n", ifp);
  		return;
  	}
  	ip6_rt_put(ifp->rt);
  
  	kfree_rcu(ifp, rcu);
  }
  
  static void
  ipv6_link_dev_addr(struct inet6_dev *idev, struct inet6_ifaddr *ifp)
  {
  	struct list_head *p;
  	int ifp_scope = ipv6_addr_src_scope(&ifp->addr);
  
  	/*
  	 * Each device address list is sorted in order of scope -
  	 * global before linklocal.
  	 */
  	list_for_each(p, &idev->addr_list) {
  		struct inet6_ifaddr *ifa
  			= list_entry(p, struct inet6_ifaddr, if_list);
  		if (ifp_scope >= ipv6_addr_src_scope(&ifa->addr))
  			break;
  	}
  
  	list_add_tail(&ifp->if_list, p);
  }
  
  static u32 inet6_addr_hash(const struct in6_addr *addr)
  {
  	return hash_32(ipv6_addr_hash(addr), IN6_ADDR_HSIZE_SHIFT);
  }
  
  /* On success it returns ifp with increased reference count */
  
  static struct inet6_ifaddr *
  ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
  	      const struct in6_addr *peer_addr, int pfxlen,
  	      int scope, u32 flags, u32 valid_lft, u32 prefered_lft)
  {
  	struct net *net = dev_net(idev->dev);
  	struct inet6_ifaddr *ifa = NULL;
  	struct rt6_info *rt;
  	struct in6_validator_info i6vi;
  	unsigned int hash;
  	int err = 0;
  	int addr_type = ipv6_addr_type(addr);
  
  	if (addr_type == IPV6_ADDR_ANY ||
  	    addr_type & IPV6_ADDR_MULTICAST ||
  	    (!(idev->dev->flags & IFF_LOOPBACK) &&
  	     addr_type & IPV6_ADDR_LOOPBACK))
  		return ERR_PTR(-EADDRNOTAVAIL);
  
  	rcu_read_lock_bh();
  
  	in6_dev_hold(idev);
  
  	if (idev->dead) {
  		err = -ENODEV;			/*XXX*/
  		goto out2;
  	}
  
  	if (idev->cnf.disable_ipv6) {
  		err = -EACCES;
  		goto out2;
  	}
  
  	i6vi.i6vi_addr = *addr;
  	i6vi.i6vi_dev = idev;
  	rcu_read_unlock_bh();
  
  	err = inet6addr_validator_notifier_call_chain(NETDEV_UP, &i6vi);
  
  	rcu_read_lock_bh();
  	err = notifier_to_errno(err);
  	if (err)
  		goto out2;
  
  	spin_lock(&addrconf_hash_lock);
  
  	/* Ignore adding duplicate addresses on an interface */
  	if (ipv6_chk_same_addr(dev_net(idev->dev), addr, idev->dev)) {
  		ADBG("ipv6_add_addr: already assigned\n");
  		err = -EEXIST;
  		goto out;
  	}
  
  	ifa = kzalloc(sizeof(struct inet6_ifaddr), GFP_ATOMIC);
  
  	if (!ifa) {
  		ADBG("ipv6_add_addr: malloc failed\n");
  		err = -ENOBUFS;
  		goto out;
  	}
  
  	rt = addrconf_dst_alloc(idev, addr, false);
  	if (IS_ERR(rt)) {
  		err = PTR_ERR(rt);
  		goto out;
  	}
  
  	if (net->ipv6.devconf_all->disable_policy ||
  	    idev->cnf.disable_policy)
  		rt->dst.flags |= DST_NOPOLICY;
  
  	neigh_parms_data_state_setall(idev->nd_parms);
  
  	ifa->addr = *addr;
  	if (peer_addr)
  		ifa->peer_addr = *peer_addr;
  
  	spin_lock_init(&ifa->lock);
  	INIT_DELAYED_WORK(&ifa->dad_work, addrconf_dad_work);
  	INIT_HLIST_NODE(&ifa->addr_lst);
  	ifa->scope = scope;
  	ifa->prefix_len = pfxlen;
  	ifa->flags = flags;
  	/* No need to add the TENTATIVE flag for addresses with NODAD */
  	if (!(flags & IFA_F_NODAD))
  		ifa->flags |= IFA_F_TENTATIVE;
  	ifa->valid_lft = valid_lft;
  	ifa->prefered_lft = prefered_lft;
  	ifa->cstamp = ifa->tstamp = jiffies;
  	ifa->tokenized = false;
  
  	ifa->rt = rt;
  
  	ifa->idev = idev;
  	/* For caller */
  	refcount_set(&ifa->refcnt, 1);
  
  	/* Add to big hash table */
  	hash = inet6_addr_hash(addr);
  
  	hlist_add_head_rcu(&ifa->addr_lst, &inet6_addr_lst[hash]);
  	spin_unlock(&addrconf_hash_lock);
  
  	write_lock(&idev->lock);
  	/* Add to inet6_dev unicast addr list. */
  	ipv6_link_dev_addr(idev, ifa);
  
  	if (ifa->flags&IFA_F_TEMPORARY) {
  		list_add(&ifa->tmp_list, &idev->tempaddr_list);
  		in6_ifa_hold(ifa);
  	}
  
  	in6_ifa_hold(ifa);
  	write_unlock(&idev->lock);
  out2:
  	rcu_read_unlock_bh();
  
  	if (likely(err == 0))
  		inet6addr_notifier_call_chain(NETDEV_UP, ifa);
  	else {
  		kfree(ifa);
  		in6_dev_put(idev);
  		ifa = ERR_PTR(err);
  	}
  
  	return ifa;
  out:
  	spin_unlock(&addrconf_hash_lock);
  	goto out2;
  }
  
  enum cleanup_prefix_rt_t {
  	CLEANUP_PREFIX_RT_NOP,    /* no cleanup action for prefix route */
  	CLEANUP_PREFIX_RT_DEL,    /* delete the prefix route */
  	CLEANUP_PREFIX_RT_EXPIRE, /* update the lifetime of the prefix route */
  };
  
  /*
   * Check, whether the prefix for ifp would still need a prefix route
   * after deleting ifp. The function returns one of the CLEANUP_PREFIX_RT_*
   * constants.
   *
   * 1) we don't purge prefix if address was not permanent.
   *    prefix is managed by its own lifetime.
   * 2) we also don't purge, if the address was IFA_F_NOPREFIXROUTE.
   * 3) if there are no addresses, delete prefix.
   * 4) if there are still other permanent address(es),
   *    corresponding prefix is still permanent.
   * 5) if there are still other addresses with IFA_F_NOPREFIXROUTE,
   *    don't purge the prefix, assume user space is managing it.
   * 6) otherwise, update prefix lifetime to the
   *    longest valid lifetime among the corresponding
   *    addresses on the device.
   *    Note: subsequent RA will update lifetime.
   **/
  static enum cleanup_prefix_rt_t
  check_cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long *expires)
  {
  	struct inet6_ifaddr *ifa;
  	struct inet6_dev *idev = ifp->idev;
  	unsigned long lifetime;
  	enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_DEL;
  
  	*expires = jiffies;
  
  	list_for_each_entry(ifa, &idev->addr_list, if_list) {
  		if (ifa == ifp)
  			continue;
  		if (!ipv6_prefix_equal(&ifa->addr, &ifp->addr,
  				       ifp->prefix_len))
  			continue;
  		if (ifa->flags & (IFA_F_PERMANENT | IFA_F_NOPREFIXROUTE))
  			return CLEANUP_PREFIX_RT_NOP;
  
  		action = CLEANUP_PREFIX_RT_EXPIRE;
  
  		spin_lock(&ifa->lock);
  
  		lifetime = addrconf_timeout_fixup(ifa->valid_lft, HZ);
  		/*
  		 * Note: Because this address is
  		 * not permanent, lifetime <
  		 * LONG_MAX / HZ here.
  		 */
  		if (time_before(*expires, ifa->tstamp + lifetime * HZ))
  			*expires = ifa->tstamp + lifetime * HZ;
  		spin_unlock(&ifa->lock);
  	}
  
  	return action;
  }
  
  static void
  cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires, bool del_rt)
  {
  	struct rt6_info *rt;
  
  	rt = addrconf_get_prefix_route(&ifp->addr,
  				       ifp->prefix_len,
  				       ifp->idev->dev,
  				       0, RTF_GATEWAY | RTF_DEFAULT);
  	if (rt) {
  		if (del_rt)
  			ip6_del_rt(rt);
  		else {
  			if (!(rt->rt6i_flags & RTF_EXPIRES))
  				rt6_set_expires(rt, expires);
  			ip6_rt_put(rt);
  		}
  	}
  }
  
  
  /* This function wants to get referenced ifp and releases it before return */
  
  static void ipv6_del_addr(struct inet6_ifaddr *ifp)
  {
  	int state;
  	enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_NOP;
  	unsigned long expires;
  
  	ASSERT_RTNL();
  
  	spin_lock_bh(&ifp->lock);
  	state = ifp->state;
  	ifp->state = INET6_IFADDR_STATE_DEAD;
  	spin_unlock_bh(&ifp->lock);
  
  	if (state == INET6_IFADDR_STATE_DEAD)
  		goto out;
  
  	spin_lock_bh(&addrconf_hash_lock);
  	hlist_del_init_rcu(&ifp->addr_lst);
  	spin_unlock_bh(&addrconf_hash_lock);
  
  	write_lock_bh(&ifp->idev->lock);
  
  	if (ifp->flags&IFA_F_TEMPORARY) {
  		list_del(&ifp->tmp_list);
  		if (ifp->ifpub) {
  			in6_ifa_put(ifp->ifpub);
  			ifp->ifpub = NULL;
  		}
  		__in6_ifa_put(ifp);
  	}
  
  	if (ifp->flags & IFA_F_PERMANENT && !(ifp->flags & IFA_F_NOPREFIXROUTE))
  		action = check_cleanup_prefix_route(ifp, &expires);
  
  	list_del_init(&ifp->if_list);
  	__in6_ifa_put(ifp);
  
  	write_unlock_bh(&ifp->idev->lock);
  
  	addrconf_del_dad_work(ifp);
  
  	ipv6_ifa_notify(RTM_DELADDR, ifp);
  
  	inet6addr_notifier_call_chain(NETDEV_DOWN, ifp);
  
  	if (action != CLEANUP_PREFIX_RT_NOP) {
  		cleanup_prefix_route(ifp, expires,
  			action == CLEANUP_PREFIX_RT_DEL);
  	}
  
  	/* clean up prefsrc entries */
  	rt6_remove_prefsrc(ifp);
  out:
  	in6_ifa_put(ifp);
  }
  
  static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, struct inet6_ifaddr *ift)
  {
  	struct inet6_dev *idev = ifp->idev;
  	struct in6_addr addr, *tmpaddr;
  	unsigned long tmp_prefered_lft, tmp_valid_lft, tmp_tstamp, age;
  	unsigned long regen_advance;
  	int tmp_plen;
  	int ret = 0;
  	u32 addr_flags;
  	unsigned long now = jiffies;
  	long max_desync_factor;
  	s32 cnf_temp_preferred_lft;
  
  	write_lock_bh(&idev->lock);
  	if (ift) {
  		spin_lock_bh(&ift->lock);
  		memcpy(&addr.s6_addr[8], &ift->addr.s6_addr[8], 8);
  		spin_unlock_bh(&ift->lock);
  		tmpaddr = &addr;
  	} else {
  		tmpaddr = NULL;
  	}
  retry:
  	in6_dev_hold(idev);
  	if (idev->cnf.use_tempaddr <= 0) {
  		write_unlock_bh(&idev->lock);
  		pr_info("%s: use_tempaddr is disabled\n", __func__);
  		in6_dev_put(idev);
  		ret = -1;
  		goto out;
  	}
  	spin_lock_bh(&ifp->lock);
  	if (ifp->regen_count++ >= idev->cnf.regen_max_retry) {
  		idev->cnf.use_tempaddr = -1;	/*XXX*/
  		spin_unlock_bh(&ifp->lock);
  		write_unlock_bh(&idev->lock);
  		pr_warn("%s: regeneration time exceeded - disabled temporary address support\n",
  			__func__);
  		in6_dev_put(idev);
  		ret = -1;
  		goto out;
  	}
  	in6_ifa_hold(ifp);
  	memcpy(addr.s6_addr, ifp->addr.s6_addr, 8);
  	ipv6_try_regen_rndid(idev, tmpaddr);
  	memcpy(&addr.s6_addr[8], idev->rndid, 8);
  	age = (now - ifp->tstamp) / HZ;
  
  	regen_advance = idev->cnf.regen_max_retry *
  			idev->cnf.dad_transmits *
  			NEIGH_VAR(idev->nd_parms, RETRANS_TIME) / HZ;
  
  	/* recalculate max_desync_factor each time and update
  	 * idev->desync_factor if it's larger
  	 */
  	cnf_temp_preferred_lft = READ_ONCE(idev->cnf.temp_prefered_lft);
  	max_desync_factor = min_t(__u32,
  				  idev->cnf.max_desync_factor,
  				  cnf_temp_preferred_lft - regen_advance);
  
  	if (unlikely(idev->desync_factor > max_desync_factor)) {
  		if (max_desync_factor > 0) {
  			get_random_bytes(&idev->desync_factor,
  					 sizeof(idev->desync_factor));
  			idev->desync_factor %= max_desync_factor;
  		} else {
  			idev->desync_factor = 0;
  		}
  	}
  
  	tmp_valid_lft = min_t(__u32,
  			      ifp->valid_lft,
  			      idev->cnf.temp_valid_lft + age);
  	tmp_prefered_lft = cnf_temp_preferred_lft + age -
  			    idev->desync_factor;
  	tmp_prefered_lft = min_t(__u32, ifp->prefered_lft, tmp_prefered_lft);
  	tmp_plen = ifp->prefix_len;
  	tmp_tstamp = ifp->tstamp;
  	spin_unlock_bh(&ifp->lock);
  
  	write_unlock_bh(&idev->lock);
  
  	/* A temporary address is created only if this calculated Preferred
  	 * Lifetime is greater than REGEN_ADVANCE time units.  In particular,
  	 * an implementation must not create a temporary address with a zero
  	 * Preferred Lifetime.
  	 * Use age calculation as in addrconf_verify to avoid unnecessary
  	 * temporary addresses being generated.
  	 */
  	age = (now - tmp_tstamp + ADDRCONF_TIMER_FUZZ_MINUS) / HZ;
  	if (tmp_prefered_lft <= regen_advance + age) {
  		in6_ifa_put(ifp);
  		in6_dev_put(idev);
  		ret = -1;
  		goto out;
  	}
  
  	addr_flags = IFA_F_TEMPORARY;
  	/* set in addrconf_prefix_rcv() */
  	if (ifp->flags & IFA_F_OPTIMISTIC)
  		addr_flags |= IFA_F_OPTIMISTIC;
  
  	ift = ipv6_add_addr(idev, &addr, NULL, tmp_plen,
  			    ipv6_addr_scope(&addr), addr_flags,
  			    tmp_valid_lft, tmp_prefered_lft);
  	if (IS_ERR(ift)) {
  		in6_ifa_put(ifp);
  		in6_dev_put(idev);
  		pr_info("%s: retry temporary address regeneration\n", __func__);
  		tmpaddr = &addr;
  		write_lock_bh(&idev->lock);
  		goto retry;
  	}
  
  	spin_lock_bh(&ift->lock);
  	ift->ifpub = ifp;
  	ift->cstamp = now;
  	ift->tstamp = tmp_tstamp;
  	spin_unlock_bh(&ift->lock);
  
  	addrconf_dad_start(ift);
  	in6_ifa_put(ift);
  	in6_dev_put(idev);
  out:
  	return ret;
  }
  
  /*
   *	Choose an appropriate source address (RFC3484)
   */
  enum {
  	IPV6_SADDR_RULE_INIT = 0,
  	IPV6_SADDR_RULE_LOCAL,
  	IPV6_SADDR_RULE_SCOPE,
  	IPV6_SADDR_RULE_PREFERRED,
  #ifdef CONFIG_IPV6_MIP6
  	IPV6_SADDR_RULE_HOA,
  #endif
  	IPV6_SADDR_RULE_OIF,
  	IPV6_SADDR_RULE_LABEL,
  	IPV6_SADDR_RULE_PRIVACY,
  	IPV6_SADDR_RULE_ORCHID,
  	IPV6_SADDR_RULE_PREFIX,
  #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
  	IPV6_SADDR_RULE_NOT_OPTIMISTIC,
  #endif
  	IPV6_SADDR_RULE_MAX
  };
  
  struct ipv6_saddr_score {
  	int			rule;
  	int			addr_type;
  	struct inet6_ifaddr	*ifa;
  	DECLARE_BITMAP(scorebits, IPV6_SADDR_RULE_MAX);
  	int			scopedist;
  	int			matchlen;
  };
  
  struct ipv6_saddr_dst {
  	const struct in6_addr *addr;
  	int ifindex;
  	int scope;
  	int label;
  	unsigned int prefs;
  };
  
  static inline int ipv6_saddr_preferred(int type)
  {
  	if (type & (IPV6_ADDR_MAPPED|IPV6_ADDR_COMPATv4|IPV6_ADDR_LOOPBACK))
  		return 1;
  	return 0;
  }
  
  static bool ipv6_use_optimistic_addr(struct net *net,
  				     struct inet6_dev *idev)
  {
  #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
  	if (!idev)
  		return false;
  	if (!net->ipv6.devconf_all->optimistic_dad && !idev->cnf.optimistic_dad)
  		return false;
  	if (!net->ipv6.devconf_all->use_optimistic && !idev->cnf.use_optimistic)
  		return false;
  
  	return true;
  #else
  	return false;
  #endif
  }
  
  static int ipv6_get_saddr_eval(struct net *net,
  			       struct ipv6_saddr_score *score,
  			       struct ipv6_saddr_dst *dst,
  			       int i)
  {
  	int ret;
  
  	if (i <= score->rule) {
  		switch (i) {
  		case IPV6_SADDR_RULE_SCOPE:
  			ret = score->scopedist;
  			break;
  		case IPV6_SADDR_RULE_PREFIX:
  			ret = score->matchlen;
  			break;
  		default:
  			ret = !!test_bit(i, score->scorebits);
  		}
  		goto out;
  	}
  
  	switch (i) {
  	case IPV6_SADDR_RULE_INIT:
  		/* Rule 0: remember if hiscore is not ready yet */
  		ret = !!score->ifa;
  		break;
  	case IPV6_SADDR_RULE_LOCAL:
  		/* Rule 1: Prefer same address */
  		ret = ipv6_addr_equal(&score->ifa->addr, dst->addr);
  		break;
  	case IPV6_SADDR_RULE_SCOPE:
  		/* Rule 2: Prefer appropriate scope
  		 *
  		 *      ret
  		 *       ^
  		 *    -1 |  d 15
  		 *    ---+--+-+---> scope
  		 *       |
  		 *       |             d is scope of the destination.
  		 *  B-d  |  \
  		 *       |   \      <- smaller scope is better if
  		 *  B-15 |    \        if scope is enough for destination.
  		 *       |             ret = B - scope (-1 <= scope >= d <= 15).
  		 * d-C-1 | /
  		 *       |/         <- greater is better
  		 *   -C  /             if scope is not enough for destination.
  		 *      /|             ret = scope - C (-1 <= d < scope <= 15).
  		 *
  		 * d - C - 1 < B -15 (for all -1 <= d <= 15).
  		 * C > d + 14 - B >= 15 + 14 - B = 29 - B.
  		 * Assume B = 0 and we get C > 29.
  		 */
  		ret = __ipv6_addr_src_scope(score->addr_type);
  		if (ret >= dst->scope)
  			ret = -ret;
  		else
  			ret -= 128;	/* 30 is enough */
  		score->scopedist = ret;
  		break;
  	case IPV6_SADDR_RULE_PREFERRED:
  	    {
  		/* Rule 3: Avoid deprecated and optimistic addresses */
  		u8 avoid = IFA_F_DEPRECATED;
  
  		if (!ipv6_use_optimistic_addr(net, score->ifa->idev))
  			avoid |= IFA_F_OPTIMISTIC;
  		ret = ipv6_saddr_preferred(score->addr_type) ||
  		      !(score->ifa->flags & avoid);
  		break;
  	    }
  #ifdef CONFIG_IPV6_MIP6
  	case IPV6_SADDR_RULE_HOA:
  	    {
  		/* Rule 4: Prefer home address */
  		int prefhome = !(dst->prefs & IPV6_PREFER_SRC_COA);
  		ret = !(score->ifa->flags & IFA_F_HOMEADDRESS) ^ prefhome;
  		break;
  	    }
  #endif
  	case IPV6_SADDR_RULE_OIF:
  		/* Rule 5: Prefer outgoing interface */
  		ret = (!dst->ifindex ||
  		       dst->ifindex == score->ifa->idev->dev->ifindex);
  		break;
  	case IPV6_SADDR_RULE_LABEL:
  		/* Rule 6: Prefer matching label */
  		ret = ipv6_addr_label(net,
  				      &score->ifa->addr, score->addr_type,
  				      score->ifa->idev->dev->ifindex) == dst->label;
  		break;
  	case IPV6_SADDR_RULE_PRIVACY:
  	    {
  		/* Rule 7: Prefer public address
  		 * Note: prefer temporary address if use_tempaddr >= 2
  		 */
  		int preftmp = dst->prefs & (IPV6_PREFER_SRC_PUBLIC|IPV6_PREFER_SRC_TMP) ?
  				!!(dst->prefs & IPV6_PREFER_SRC_TMP) :
  				score->ifa->idev->cnf.use_tempaddr >= 2;
  		ret = (!(score->ifa->flags & IFA_F_TEMPORARY)) ^ preftmp;
  		break;
  	    }
  	case IPV6_SADDR_RULE_ORCHID:
  		/* Rule 8-: Prefer ORCHID vs ORCHID or
  		 *	    non-ORCHID vs non-ORCHID
  		 */
  		ret = !(ipv6_addr_orchid(&score->ifa->addr) ^
  			ipv6_addr_orchid(dst->addr));
  		break;
  	case IPV6_SADDR_RULE_PREFIX:
  		/* Rule 8: Use longest matching prefix */
  		ret = ipv6_addr_diff(&score->ifa->addr, dst->addr);
  		if (ret > score->ifa->prefix_len)
  			ret = score->ifa->prefix_len;
  		score->matchlen = ret;
  		break;
  #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
  	case IPV6_SADDR_RULE_NOT_OPTIMISTIC:
  		/* Optimistic addresses still have lower precedence than other
  		 * preferred addresses.
  		 */
  		ret = !(score->ifa->flags & IFA_F_OPTIMISTIC);
  		break;
  #endif
  	default:
  		ret = 0;
  	}
  
  	if (ret)
  		__set_bit(i, score->scorebits);
  	score->rule = i;
  out:
  	return ret;
  }
  
  static int __ipv6_dev_get_saddr(struct net *net,
  				struct ipv6_saddr_dst *dst,
  				struct inet6_dev *idev,
  				struct ipv6_saddr_score *scores,
  				int hiscore_idx)
  {
  	struct ipv6_saddr_score *score = &scores[1 - hiscore_idx], *hiscore = &scores[hiscore_idx];
  
  	read_lock_bh(&idev->lock);
  	list_for_each_entry(score->ifa, &idev->addr_list, if_list) {
  		int i;
  
  		/*
  		 * - Tentative Address (RFC2462 section 5.4)
  		 *  - A tentative address is not considered
  		 *    "assigned to an interface" in the traditional
  		 *    sense, unless it is also flagged as optimistic.
  		 * - Candidate Source Address (section 4)
  		 *  - In any case, anycast addresses, multicast
  		 *    addresses, and the unspecified address MUST
  		 *    NOT be included in a candidate set.
  		 */
  		if ((score->ifa->flags & IFA_F_TENTATIVE) &&
  		    (!(score->ifa->flags & IFA_F_OPTIMISTIC)))
  			continue;
  
  		score->addr_type = __ipv6_addr_type(&score->ifa->addr);
  
  		if (unlikely(score->addr_type == IPV6_ADDR_ANY ||
  			     score->addr_type & IPV6_ADDR_MULTICAST)) {
  			net_dbg_ratelimited("ADDRCONF: unspecified / multicast address assigned as unicast address on %s",
  					    idev->dev->name);
  			continue;
  		}
  
  		score->rule = -1;
  		bitmap_zero(score->scorebits, IPV6_SADDR_RULE_MAX);
  
  		for (i = 0; i < IPV6_SADDR_RULE_MAX; i++) {
  			int minihiscore, miniscore;
  
  			minihiscore = ipv6_get_saddr_eval(net, hiscore, dst, i);
  			miniscore = ipv6_get_saddr_eval(net, score, dst, i);
  
  			if (minihiscore > miniscore) {
  				if (i == IPV6_SADDR_RULE_SCOPE &&
  				    score->scopedist > 0) {
  					/*
  					 * special case:
  					 * each remaining entry
  					 * has too small (not enough)
  					 * scope, because ifa entries
  					 * are sorted by their scope
  					 * values.
  					 */
  					goto out;
  				}
  				break;
  			} else if (minihiscore < miniscore) {
  				if (hiscore->ifa)
  					in6_ifa_put(hiscore->ifa);
  
  				in6_ifa_hold(score->ifa);
  
  				swap(hiscore, score);
  				hiscore_idx = 1 - hiscore_idx;
  
  				/* restore our iterator */
  				score->ifa = hiscore->ifa;
  
  				break;
  			}
  		}
  	}
  out:
  	read_unlock_bh(&idev->lock);
  	return hiscore_idx;
  }
  
  static int ipv6_get_saddr_master(struct net *net,
  				 const struct net_device *dst_dev,
  				 const struct net_device *master,
  				 struct ipv6_saddr_dst *dst,
  				 struct ipv6_saddr_score *scores,
  				 int hiscore_idx)
  {
  	struct inet6_dev *idev;
  
  	idev = __in6_dev_get(dst_dev);
  	if (idev)
  		hiscore_idx = __ipv6_dev_get_saddr(net, dst, idev,
  						   scores, hiscore_idx);
  
  	idev = __in6_dev_get(master);
  	if (idev)
  		hiscore_idx = __ipv6_dev_get_saddr(net, dst, idev,
  						   scores, hiscore_idx);
  
  	return hiscore_idx;
  }
  
  int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
  		       const struct in6_addr *daddr, unsigned int prefs,
  		       struct in6_addr *saddr)
  {
  	struct ipv6_saddr_score scores[2], *hiscore;
  	struct ipv6_saddr_dst dst;
  	struct inet6_dev *idev;
  	struct net_device *dev;
  	int dst_type;
  	bool use_oif_addr = false;
  	int hiscore_idx = 0;
  
  	dst_type = __ipv6_addr_type(daddr);
  	dst.addr = daddr;
  	dst.ifindex = dst_dev ? dst_dev->ifindex : 0;
  	dst.scope = __ipv6_addr_src_scope(dst_type);
  	dst.label = ipv6_addr_label(net, daddr, dst_type, dst.ifindex);
  	dst.prefs = prefs;
  
  	scores[hiscore_idx].rule = -1;
  	scores[hiscore_idx].ifa = NULL;
  
  	rcu_read_lock();
  
  	/* Candidate Source Address (section 4)
  	 *  - multicast and link-local destination address,
  	 *    the set of candidate source address MUST only
  	 *    include addresses assigned to interfaces
  	 *    belonging to the same link as the outgoing
  	 *    interface.
  	 * (- For site-local destination addresses, the
  	 *    set of candidate source addresses MUST only
  	 *    include addresses assigned to interfaces
  	 *    belonging to the same site as the outgoing
  	 *    interface.)
  	 *  - "It is RECOMMENDED that the candidate source addresses
  	 *    be the set of unicast addresses assigned to the
  	 *    interface that will be used to send to the destination
  	 *    (the 'outgoing' interface)." (RFC 6724)
  	 */
  	if (dst_dev) {
  		idev = __in6_dev_get(dst_dev);
  		if ((dst_type & IPV6_ADDR_MULTICAST) ||
  		    dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL ||
  		    (idev && idev->cnf.use_oif_addrs_only)) {
  			use_oif_addr = true;
  		}
  	}
  
  	if (use_oif_addr) {
  		if (idev)
  			hiscore_idx = __ipv6_dev_get_saddr(net, &dst, idev, scores, hiscore_idx);
  	} else {
  		const struct net_device *master;
  		int master_idx = 0;
  
  		/* if dst_dev exists and is enslaved to an L3 device, then
  		 * prefer addresses from dst_dev and then the master over
  		 * any other enslaved devices in the L3 domain.
  		 */
  		master = l3mdev_master_dev_rcu(dst_dev);
  		if (master) {
  			master_idx = master->ifindex;
  
  			hiscore_idx = ipv6_get_saddr_master(net, dst_dev,
  							    master, &dst,
  							    scores, hiscore_idx);
  
  			if (scores[hiscore_idx].ifa)
  				goto out;
  		}
  
  		for_each_netdev_rcu(net, dev) {
  			/* only consider addresses on devices in the
  			 * same L3 domain
  			 */
  			if (l3mdev_master_ifindex_rcu(dev) != master_idx)
  				continue;
  			idev = __in6_dev_get(dev);
  			if (!idev)
  				continue;
  			hiscore_idx = __ipv6_dev_get_saddr(net, &dst, idev, scores, hiscore_idx);
  		}
  	}
  
  out:
  	rcu_read_unlock();
  
  	hiscore = &scores[hiscore_idx];
  	if (!hiscore->ifa)
  		return -EADDRNOTAVAIL;
  
  	*saddr = hiscore->ifa->addr;
  	in6_ifa_put(hiscore->ifa);
  	return 0;
  }
  EXPORT_SYMBOL(ipv6_dev_get_saddr);
  
  int __ipv6_get_lladdr(struct inet6_dev *idev, struct in6_addr *addr,
  		      u32 banned_flags)
  {
  	struct inet6_ifaddr *ifp;
  	int err = -EADDRNOTAVAIL;
  
  	list_for_each_entry_reverse(ifp, &idev->addr_list, if_list) {
  		if (ifp->scope > IFA_LINK)
  			break;
  		if (ifp->scope == IFA_LINK &&
  		    !(ifp->flags & banned_flags)) {
  			*addr = ifp->addr;
  			err = 0;
  			break;
  		}
  	}
  	return err;
  }
  
  int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
  		    u32 banned_flags)
  {
  	struct inet6_dev *idev;
  	int err = -EADDRNOTAVAIL;
  
  	rcu_read_lock();
  	idev = __in6_dev_get(dev);
  	if (idev) {
  		read_lock_bh(&idev->lock);
  		err = __ipv6_get_lladdr(idev, addr, banned_flags);
  		read_unlock_bh(&idev->lock);
  	}
  	rcu_read_unlock();
  	return err;
  }
  
  static int ipv6_count_addresses(struct inet6_dev *idev)
  {
  	int cnt = 0;
  	struct inet6_ifaddr *ifp;
  
  	read_lock_bh(&idev->lock);
  	list_for_each_entry(ifp, &idev->addr_list, if_list)
  		cnt++;
  	read_unlock_bh(&idev->lock);
  	return cnt;
  }
  
  int ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
  		  const struct net_device *dev, int strict)
  {
  	return ipv6_chk_addr_and_flags(net, addr, dev, strict, IFA_F_TENTATIVE);
  }
  EXPORT_SYMBOL(ipv6_chk_addr);
  
  int ipv6_chk_addr_and_flags(struct net *net, const struct in6_addr *addr,
  			    const struct net_device *dev, int strict,
  			    u32 banned_flags)
  {
  	struct inet6_ifaddr *ifp;
  	unsigned int hash = inet6_addr_hash(addr);
  	u32 ifp_flags;
  
  	rcu_read_lock_bh();
  	hlist_for_each_entry_rcu(ifp, &inet6_addr_lst[hash], addr_lst) {
  		if (!net_eq(dev_net(ifp->idev->dev), net))
  			continue;
  		/* Decouple optimistic from tentative for evaluation here.
  		 * Ban optimistic addresses explicitly, when required.
  		 */
  		ifp_flags = (ifp->flags&IFA_F_OPTIMISTIC)
  			    ? (ifp->flags&~IFA_F_TENTATIVE)
  			    : ifp->flags;
  		if (ipv6_addr_equal(&ifp->addr, addr) &&
  		    !(ifp_flags&banned_flags) &&
  		    (!dev || ifp->idev->dev == dev ||
  		     !(ifp->scope&(IFA_LINK|IFA_HOST) || strict))) {
  			rcu_read_unlock_bh();
  			return 1;
  		}
  	}
  
  	rcu_read_unlock_bh();
  	return 0;
  }
  EXPORT_SYMBOL(ipv6_chk_addr_and_flags);
  
  static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
  			       struct net_device *dev)
  {
  	unsigned int hash = inet6_addr_hash(addr);
  	struct inet6_ifaddr *ifp;
  
  	hlist_for_each_entry(ifp, &inet6_addr_lst[hash], addr_lst) {
  		if (!net_eq(dev_net(ifp->idev->dev), net))
  			continue;
  		if (ipv6_addr_equal(&ifp->addr, addr)) {
  			if (!dev || ifp->idev->dev == dev)
  				return true;
  		}
  	}
  	return false;
  }
  
  /* Compares an address/prefix_len with addresses on device @dev.
   * If one is found it returns true.
   */
  bool ipv6_chk_custom_prefix(const struct in6_addr *addr,
  	const unsigned int prefix_len, struct net_device *dev)
  {
  	struct inet6_dev *idev;
  	struct inet6_ifaddr *ifa;
  	bool ret = false;
  
  	rcu_read_lock();
  	idev = __in6_dev_get(dev);
  	if (idev) {
  		read_lock_bh(&idev->lock);
  		list_for_each_entry(ifa, &idev->addr_list, if_list) {
  			ret = ipv6_prefix_equal(addr, &ifa->addr, prefix_len);
  			if (ret)
  				break;
  		}
  		read_unlock_bh(&idev->lock);
  	}
  	rcu_read_unlock();
  
  	return ret;
  }
  EXPORT_SYMBOL(ipv6_chk_custom_prefix);
  
  int ipv6_chk_prefix(const struct in6_addr *addr, struct net_device *dev)
  {
  	struct inet6_dev *idev;
  	struct inet6_ifaddr *ifa;
  	int	onlink;
  
  	onlink = 0;
  	rcu_read_lock();
  	idev = __in6_dev_get(dev);
  	if (idev) {
  		read_lock_bh(&idev->lock);
  		list_for_each_entry(ifa, &idev->addr_list, if_list) {
  			onlink = ipv6_prefix_equal(addr, &ifa->addr,
  						   ifa->prefix_len);
  			if (onlink)
  				break;
  		}
  		read_unlock_bh(&idev->lock);
  	}
  	rcu_read_unlock();
  	return onlink;
  }
  EXPORT_SYMBOL(ipv6_chk_prefix);
  
  struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, const struct in6_addr *addr,
  				     struct net_device *dev, int strict)
  {
  	struct inet6_ifaddr *ifp, *result = NULL;
  	unsigned int hash = inet6_addr_hash(addr);
  
  	rcu_read_lock_bh();
  	hlist_for_each_entry_rcu_bh(ifp, &inet6_addr_lst[hash], addr_lst) {
  		if (!net_eq(dev_net(ifp->idev->dev), net))
  			continue;
  		if (ipv6_addr_equal(&ifp->addr, addr)) {
  			if (!dev || ifp->idev->dev == dev ||
  			    !(ifp->scope&(IFA_LINK|IFA_HOST) || strict)) {
  				result = ifp;
  				in6_ifa_hold(ifp);
  				break;
  			}
  		}
  	}
  	rcu_read_unlock_bh();
  
  	return result;
  }
  
  /* Gets referenced address, destroys ifaddr */
  
  static void addrconf_dad_stop(struct inet6_ifaddr *ifp, int dad_failed)
  {
  	if (dad_failed)
  		ifp->flags |= IFA_F_DADFAILED;
  
  	if (ifp->flags&IFA_F_TEMPORARY) {
  		struct inet6_ifaddr *ifpub;
  		spin_lock_bh(&ifp->lock);
  		ifpub = ifp->ifpub;
  		if (ifpub) {
  			in6_ifa_hold(ifpub);
  			spin_unlock_bh(&ifp->lock);
  			ipv6_create_tempaddr(ifpub, ifp);
  			in6_ifa_put(ifpub);
  		} else {
  			spin_unlock_bh(&ifp->lock);
  		}
  		ipv6_del_addr(ifp);
  	} else if (ifp->flags&IFA_F_PERMANENT || !dad_failed) {
  		spin_lock_bh(&ifp->lock);
  		addrconf_del_dad_work(ifp);
  		ifp->flags |= IFA_F_TENTATIVE;
  		spin_unlock_bh(&ifp->lock);
  		if (dad_failed)
  			ipv6_ifa_notify(0, ifp);
  		in6_ifa_put(ifp);
  	} else {
  		ipv6_del_addr(ifp);
  	}
  }
  
  static int addrconf_dad_end(struct inet6_ifaddr *ifp)
  {
  	int err = -ENOENT;
  
  	spin_lock_bh(&ifp->lock);
  	if (ifp->state == INET6_IFADDR_STATE_DAD) {
  		ifp->state = INET6_IFADDR_STATE_POSTDAD;
  		err = 0;
  	}
  	spin_unlock_bh(&ifp->lock);
  
  	return err;
  }
  
  void addrconf_dad_failure(struct inet6_ifaddr *ifp)
  {
  	struct inet6_dev *idev = ifp->idev;
  	struct net *net = dev_net(ifp->idev->dev);
  
  	if (addrconf_dad_end(ifp)) {
  		in6_ifa_put(ifp);
  		return;
  	}
  
  	net_info_ratelimited("%s: IPv6 duplicate address %pI6c detected!\n",
  			     ifp->idev->dev->name, &ifp->addr);
  
  	spin_lock_bh(&ifp->lock);
  
  	if (ifp->flags & IFA_F_STABLE_PRIVACY) {
  		int scope = ifp->scope;
  		u32 flags = ifp->flags;
  		struct in6_addr new_addr;
  		struct inet6_ifaddr *ifp2;
  		u32 valid_lft, preferred_lft;
  		int pfxlen = ifp->prefix_len;
  		int retries = ifp->stable_privacy_retry + 1;
  
  		if (retries > net->ipv6.sysctl.idgen_retries) {
  			net_info_ratelimited("%s: privacy stable address generation failed because of DAD conflicts!\n",
  					     ifp->idev->dev->name);
  			goto errdad;
  		}
  
  		new_addr = ifp->addr;
  		if (ipv6_generate_stable_address(&new_addr, retries,
  						 idev))
  			goto errdad;
  
  		valid_lft = ifp->valid_lft;
  		preferred_lft = ifp->prefered_lft;
  
  		spin_unlock_bh(&ifp->lock);
  
  		if (idev->cnf.max_addresses &&
  		    ipv6_count_addresses(idev) >=
  		    idev->cnf.max_addresses)
  			goto lock_errdad;
  
  		net_info_ratelimited("%s: generating new stable privacy address because of DAD conflict\n",
  				     ifp->idev->dev->name);
  
  		ifp2 = ipv6_add_addr(idev, &new_addr, NULL, pfxlen,
  				     scope, flags, valid_lft,
  				     preferred_lft);
  		if (IS_ERR(ifp2))
  			goto lock_errdad;
  
  		spin_lock_bh(&ifp2->lock);
  		ifp2->stable_privacy_retry = retries;
  		ifp2->state = INET6_IFADDR_STATE_PREDAD;
  		spin_unlock_bh(&ifp2->lock);
  
  		addrconf_mod_dad_work(ifp2, net->ipv6.sysctl.idgen_delay);
  		in6_ifa_put(ifp2);
  lock_errdad:
  		spin_lock_bh(&ifp->lock);
  	}
  
  errdad:
  	/* transition from _POSTDAD to _ERRDAD */
  	ifp->state = INET6_IFADDR_STATE_ERRDAD;
  	spin_unlock_bh(&ifp->lock);
  
  	addrconf_mod_dad_work(ifp, 0);
  	in6_ifa_put(ifp);
  }
  
  /* Join to solicited addr multicast group.
   * caller must hold RTNL */
  void addrconf_join_solict(struct net_device *dev, const struct in6_addr *addr)
  {
  	struct in6_addr maddr;
  
  	if (dev->flags&(IFF_LOOPBACK|IFF_NOARP))
  		return;
  
  	addrconf_addr_solict_mult(addr, &maddr);
  	ipv6_dev_mc_inc(dev, &maddr);
  }
  
  /* caller must hold RTNL */
  void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr)
  {
  	struct in6_addr maddr;
  
  	if (idev->dev->flags&(IFF_LOOPBACK|IFF_NOARP))
  		return;
  
  	addrconf_addr_solict_mult(addr, &maddr);
  	__ipv6_dev_mc_dec(idev, &maddr);
  }
  
  /* caller must hold RTNL */
  static void addrconf_join_anycast(struct inet6_ifaddr *ifp)
  {
  	struct in6_addr addr;
  
  	if (ifp->prefix_len >= 127) /* RFC 6164 */
  		return;
  	ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
  	if (ipv6_addr_any(&addr))
  		return;
  	__ipv6_dev_ac_inc(ifp->idev, &addr);
  }
  
  /* caller must hold RTNL */
  static void addrconf_leave_anycast(struct inet6_ifaddr *ifp)
  {
  	struct in6_addr addr;
  
  	if (ifp->prefix_len >= 127) /* RFC 6164 */
  		return;
  	ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
  	if (ipv6_addr_any(&addr))
  		return;
  	__ipv6_dev_ac_dec(ifp->idev, &addr);
  }
  
  static int addrconf_ifid_6lowpan(u8 *eui, struct net_device *dev)
  {
  	switch (dev->addr_len) {
  	case ETH_ALEN:
  		memcpy(eui, dev->dev_addr, 3);
  		eui[3] = 0xFF;
  		eui[4] = 0xFE;
  		memcpy(eui + 5, dev->dev_addr + 3, 3);
  		break;
  	case EUI64_ADDR_LEN:
  		memcpy(eui, dev->dev_addr, EUI64_ADDR_LEN);
  		eui[0] ^= 2;
  		break;
  	default:
  		return -1;
  	}
  
  	return 0;
  }
  
  static int addrconf_ifid_ieee1394(u8 *eui, struct net_device *dev)
  {
  	union fwnet_hwaddr *ha;
  
  	if (dev->addr_len != FWNET_ALEN)
  		return -1;
  
  	ha = (union fwnet_hwaddr *)dev->dev_addr;
  
  	memcpy(eui, &ha->uc.uniq_id, sizeof(ha->uc.uniq_id));
  	eui[0] ^= 2;
  	return 0;
  }
  
  static int addrconf_ifid_arcnet(u8 *eui, struct net_device *dev)
  {
  	/* XXX: inherit EUI-64 from other interface -- yoshfuji */
  	if (dev->addr_len != ARCNET_ALEN)
  		return -1;
  	memset(eui, 0, 7);
  	eui[7] = *(u8 *)dev->dev_addr;
  	return 0;
  }
  
  static int addrconf_ifid_infiniband(u8 *eui, struct net_device *dev)
  {
  	if (dev->addr_len != INFINIBAND_ALEN)
  		return -1;
  	memcpy(eui, dev->dev_addr + 12, 8);
  	eui[0] |= 2;
  	return 0;
  }
  
  static int __ipv6_isatap_ifid(u8 *eui, __be32 addr)
  {
  	if (addr == 0)
  		return -1;
  	eui[0] = (ipv4_is_zeronet(addr) || ipv4_is_private_10(addr) ||
  		  ipv4_is_loopback(addr) || ipv4_is_linklocal_169(addr) ||
  		  ipv4_is_private_172(addr) || ipv4_is_test_192(addr) ||
  		  ipv4_is_anycast_6to4(addr) || ipv4_is_private_192(addr) ||
  		  ipv4_is_test_198(addr) || ipv4_is_multicast(addr) ||
  		  ipv4_is_lbcast(addr)) ? 0x00 : 0x02;
  	eui[1] = 0;
  	eui[2] = 0x5E;
  	eui[3] = 0xFE;
  	memcpy(eui + 4, &addr, 4);
  	return 0;
  }
  
  static int addrconf_ifid_sit(u8 *eui, struct net_device *dev)
  {
  	if (dev->priv_flags & IFF_ISATAP)
  		return __ipv6_isatap_ifid(eui, *(__be32 *)dev->dev_addr);
  	return -1;
  }
  
  static int addrconf_ifid_gre(u8 *eui, struct net_device *dev)
  {
  	return __ipv6_isatap_ifid(eui, *(__be32 *)dev->dev_addr);
  }
  
  static int addrconf_ifid_ip6tnl(u8 *eui, struct net_device *dev)
  {
  	memcpy(eui, dev->perm_addr, 3);
  	memcpy(eui + 5, dev->perm_addr + 3, 3);
  	eui[3] = 0xFF;
  	eui[4] = 0xFE;
  	eui[0] ^= 2;
  	return 0;
  }
  
  static int ipv6_generate_eui64(u8 *eui, struct net_device *dev)
  {
  	switch (dev->type) {
  	case ARPHRD_ETHER:
  	case ARPHRD_FDDI:
  		return addrconf_ifid_eui48(eui, dev);
  	case ARPHRD_ARCNET:
  		return addrconf_ifid_arcnet(eui, dev);
  	case ARPHRD_INFINIBAND:
  		return addrconf_ifid_infiniband(eui, dev);
  	case ARPHRD_SIT:
  		return addrconf_ifid_sit(eui, dev);
  	case ARPHRD_IPGRE:
  	case ARPHRD_TUNNEL:
  		return addrconf_ifid_gre(eui, dev);
  	case ARPHRD_6LOWPAN:
  		return addrconf_ifid_6lowpan(eui, dev);
  	case ARPHRD_IEEE1394:
  		return addrconf_ifid_ieee1394(eui, dev);
  	case ARPHRD_TUNNEL6:
  	case ARPHRD_IP6GRE:
  		return addrconf_ifid_ip6tnl(eui, dev);
  	}
  	return -1;
  }
  
  static int ipv6_inherit_eui64(u8 *eui, struct inet6_dev *idev)
  {
  	int err = -1;
  	struct inet6_ifaddr *ifp;
  
  	read_lock_bh(&idev->lock);
  	list_for_each_entry_reverse(ifp, &idev->addr_list, if_list) {
  		if (ifp->scope > IFA_LINK)
  			break;
  		if (ifp->scope == IFA_LINK && !(ifp->flags&IFA_F_TENTATIVE)) {
  			memcpy(eui, ifp->addr.s6_addr+8, 8);
  			err = 0;
  			break;
  		}
  	}
  	read_unlock_bh(&idev->lock);
  	return err;
  }
  
  /* (re)generation of randomized interface identifier (RFC 3041 3.2, 3.5) */
  static void ipv6_regen_rndid(struct inet6_dev *idev)
  {
  regen:
  	get_random_bytes(idev->rndid, sizeof(idev->rndid));
  	idev->rndid[0] &= ~0x02;
  
  	/*
  	 * <draft-ietf-ipngwg-temp-addresses-v2-00.txt>:
  	 * check if generated address is not inappropriate
  	 *
  	 *  - Reserved subnet anycast (RFC 2526)
  	 *	11111101 11....11 1xxxxxxx
  	 *  - ISATAP (RFC4214) 6.1
  	 *	00-00-5E-FE-xx-xx-xx-xx
  	 *  - value 0
  	 *  - XXX: already assigned to an address on the device
  	 */
  	if (idev->rndid[0] == 0xfd &&
  	    (idev->rndid[1]&idev->rndid[2]&idev->rndid[3]&idev->rndid[4]&idev->rndid[5]&idev->rndid[6]) == 0xff &&
  	    (idev->rndid[7]&0x80))
  		goto regen;
  	if ((idev->rndid[0]|idev->rndid[1]) == 0) {
  		if (idev->rndid[2] == 0x5e && idev->rndid[3] == 0xfe)
  			goto regen;
  		if ((idev->rndid[2]|idev->rndid[3]|idev->rndid[4]|idev->rndid[5]|idev->rndid[6]|idev->rndid[7]) == 0x00)
  			goto regen;
  	}
  }
  
  static void  ipv6_try_regen_rndid(struct inet6_dev *idev, struct in6_addr *tmpaddr)
  {
  	if (tmpaddr && memcmp(idev->rndid, &tmpaddr->s6_addr[8], 8) == 0)
  		ipv6_regen_rndid(idev);
  }
  
  /*
   *	Add prefix route.
   */
  
  static void
  addrconf_prefix_route(struct in6_addr *pfx, int plen, struct net_device *dev,
  		      unsigned long expires, u32 flags)
  {
  	struct fib6_config cfg = {
  		.fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_PREFIX,
  		.fc_metric = IP6_RT_PRIO_ADDRCONF,
  		.fc_ifindex = dev->ifindex,
  		.fc_expires = expires,
  		.fc_dst_len = plen,
  		.fc_flags = RTF_UP | flags,
  		.fc_nlinfo.nl_net = dev_net(dev),
  		.fc_protocol = RTPROT_KERNEL,
  	};
  
  	cfg.fc_dst = *pfx;
  
  	/* Prevent useless cloning on PtP SIT.
  	   This thing is done here expecting that the whole
  	   class of non-broadcast devices need not cloning.
  	 */
  #if IS_ENABLED(CONFIG_IPV6_SIT)
  	if (dev->type == ARPHRD_SIT && (dev->flags & IFF_POINTOPOINT))
  		cfg.fc_flags |= RTF_NONEXTHOP;
  #endif
  
  	ip6_route_add(&cfg, NULL);
  }
  
  
  static struct rt6_info *addrconf_get_prefix_route(const struct in6_addr *pfx,
  						  int plen,
  						  const struct net_device *dev,
  						  u32 flags, u32 noflags)
  {
  	struct fib6_node *fn;
  	struct rt6_info *rt = NULL;
  	struct fib6_table *table;
  	u32 tb_id = l3mdev_fib_table(dev) ? : RT6_TABLE_PREFIX;
  
  	table = fib6_get_table(dev_net(dev), tb_id);
  	if (!table)
  		return NULL;
  
  	read_lock_bh(&table->tb6_lock);
  	fn = fib6_locate(&table->tb6_root, pfx, plen, NULL, 0);
  	if (!fn)
  		goto out;
  
  	noflags |= RTF_CACHE;
  	for (rt = fn->leaf; rt; rt = rt->dst.rt6_next) {
  		if (rt->dst.dev->ifindex != dev->ifindex)
  			continue;
  		if ((rt->rt6i_flags & flags) != flags)
  			continue;
  		if ((rt->rt6i_flags & noflags) != 0)
  			continue;
  		dst_hold(&rt->dst);
  		break;
  	}
  out:
  	read_unlock_bh(&table->tb6_lock);
  	return rt;
  }
  
  
  /* Create "default" multicast route to the interface */
  
  static void addrconf_add_mroute(struct net_device *dev)
  {
  	struct fib6_config cfg = {
  		.fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_LOCAL,
  		.fc_metric = IP6_RT_PRIO_ADDRCONF,
  		.fc_ifindex = dev->ifindex,
  		.fc_dst_len = 8,
  		.fc_flags = RTF_UP,
  		.fc_nlinfo.nl_net = dev_net(dev),
  	};
  
  	ipv6_addr_set(&cfg.fc_dst, htonl(0xFF000000), 0, 0, 0);
  
  	ip6_route_add(&cfg, NULL);
  }
  
  static struct inet6_dev *addrconf_add_dev(struct net_device *dev)
  {
  	struct inet6_dev *idev;
  
  	ASSERT_RTNL();
  
  	idev = ipv6_find_idev(dev);
  	if (!idev)
  		return ERR_PTR(-ENOBUFS);
  
  	if (idev->cnf.disable_ipv6)
  		return ERR_PTR(-EACCES);
  
  	/* Add default multicast route */
  	if (!(dev->flags & IFF_LOOPBACK) && !netif_is_l3_master(dev))
  		addrconf_add_mroute(dev);
  
  	return idev;
  }
  
  static void manage_tempaddrs(struct inet6_dev *idev,
  			     struct inet6_ifaddr *ifp,
  			     __u32 valid_lft, __u32 prefered_lft,
  			     bool create, unsigned long now)
  {
  	u32 flags;
  	struct inet6_ifaddr *ift;
  
  	read_lock_bh(&idev->lock);
  	/* update all temporary addresses in the list */
  	list_for_each_entry(ift, &idev->tempaddr_list, tmp_list) {
  		int age, max_valid, max_prefered;
  
  		if (ifp != ift->ifpub)
  			continue;
  
  		/* RFC 4941 section 3.3:
  		 * If a received option will extend the lifetime of a public
  		 * address, the lifetimes of temporary addresses should
  		 * be extended, subject to the overall constraint that no
  		 * temporary addresses should ever remain "valid" or "preferred"
  		 * for a time longer than (TEMP_VALID_LIFETIME) or
  		 * (TEMP_PREFERRED_LIFETIME - DESYNC_FACTOR), respectively.
  		 */
  		age = (now - ift->cstamp) / HZ;
  		max_valid = idev->cnf.temp_valid_lft - age;
  		if (max_valid < 0)
  			max_valid = 0;
  
  		max_prefered = idev->cnf.temp_prefered_lft -
  			       idev->desync_factor - age;
  		if (max_prefered < 0)
  			max_prefered = 0;
  
  		if (valid_lft > max_valid)
  			valid_lft = max_valid;
  
  		if (prefered_lft > max_prefered)
  			prefered_lft = max_prefered;
  
  		spin_lock(&ift->lock);
  		flags = ift->flags;
  		ift->valid_lft = valid_lft;
  		ift->prefered_lft = prefered_lft;
  		ift->tstamp = now;
  		if (prefered_lft > 0)
  			ift->flags &= ~IFA_F_DEPRECATED;
  
  		spin_unlock(&ift->lock);
  		if (!(flags&IFA_F_TENTATIVE))
  			ipv6_ifa_notify(0, ift);
  	}
  
  	if ((create || list_empty(&idev->tempaddr_list)) &&
  	    idev->cnf.use_tempaddr > 0) {
  		/* When a new public address is created as described
  		 * in [ADDRCONF], also create a new temporary address.
  		 * Also create a temporary address if it's enabled but
  		 * no temporary address currently exists.
  		 */
  		read_unlock_bh(&idev->lock);
  		ipv6_create_tempaddr(ifp, NULL);
  	} else {
  		read_unlock_bh(&idev->lock);
  	}
  }
  
  static bool is_addr_mode_generate_stable(struct inet6_dev *idev)
  {
  	return idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY ||
  	       idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM;
  }
  
  int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
  				 const struct prefix_info *pinfo,
  				 struct inet6_dev *in6_dev,
  				 const struct in6_addr *addr, int addr_type,
  				 u32 addr_flags, bool sllao, bool tokenized,
  				 __u32 valid_lft, u32 prefered_lft)
  {
  	struct inet6_ifaddr *ifp = ipv6_get_ifaddr(net, addr, dev, 1);
  	int create = 0, update_lft = 0;
  
  	if (!ifp && valid_lft) {
  		int max_addresses = in6_dev->cnf.max_addresses;
  
  #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
  		if ((net->ipv6.devconf_all->optimistic_dad ||
  		     in6_dev->cnf.optimistic_dad) &&
  		    !net->ipv6.devconf_all->forwarding && sllao)
  			addr_flags |= IFA_F_OPTIMISTIC;
  #endif
  
  		/* Do not allow to create too much of autoconfigured
  		 * addresses; this would be too easy way to crash kernel.
  		 */
  		if (!max_addresses ||
  		    ipv6_count_addresses(in6_dev) < max_addresses)
  			ifp = ipv6_add_addr(in6_dev, addr, NULL,
  					    pinfo->prefix_len,
  					    addr_type&IPV6_ADDR_SCOPE_MASK,
  					    addr_flags, valid_lft,
  					    prefered_lft);
  
  		if (IS_ERR_OR_NULL(ifp))
  			return -1;
  
  		update_lft = 0;
  		create = 1;
  		spin_lock_bh(&ifp->lock);
  		ifp->flags |= IFA_F_MANAGETEMPADDR;
  		ifp->cstamp = jiffies;
  		ifp->tokenized = tokenized;
  		spin_unlock_bh(&ifp->lock);
  		addrconf_dad_start(ifp);
  	}
  
  	if (ifp) {
  		u32 flags;
  		unsigned long now;
  		u32 stored_lft;
  
  		/* update lifetime (RFC2462 5.5.3 e) */
  		spin_lock_bh(&ifp->lock);
  		now = jiffies;
  		if (ifp->valid_lft > (now - ifp->tstamp) / HZ)
  			stored_lft = ifp->valid_lft - (now - ifp->tstamp) / HZ;
  		else
  			stored_lft = 0;
  		if (!update_lft && !create && stored_lft) {
  			const u32 minimum_lft = min_t(u32,
  				stored_lft, MIN_VALID_LIFETIME);
  			valid_lft = max(valid_lft, minimum_lft);
  
  			/* RFC4862 Section 5.5.3e:
  			 * "Note that the preferred lifetime of the
  			 *  corresponding address is always reset to
  			 *  the Preferred Lifetime in the received
  			 *  Prefix Information option, regardless of
  			 *  whether the valid lifetime is also reset or
  			 *  ignored."
  			 *
  			 * So we should always update prefered_lft here.
  			 */
  			update_lft = 1;
  		}
  
  		if (update_lft) {
  			ifp->valid_lft = valid_lft;
  			ifp->prefered_lft = prefered_lft;
  			ifp->tstamp = now;
  			flags = ifp->flags;
  			ifp->flags &= ~IFA_F_DEPRECATED;
  			spin_unlock_bh(&ifp->lock);
  
  			if (!(flags&IFA_F_TENTATIVE))
  				ipv6_ifa_notify(0, ifp);
  		} else
  			spin_unlock_bh(&ifp->lock);
  
  		manage_tempaddrs(in6_dev, ifp, valid_lft, prefered_lft,
  				 create, now);
  
  		in6_ifa_put(ifp);
  		addrconf_verify();
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(addrconf_prefix_rcv_add_addr);
  
  void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
  {
  	struct prefix_info *pinfo;
  	__u32 valid_lft;
  	__u32 prefered_lft;
  	int addr_type, err;
  	u32 addr_flags = 0;
  	struct inet6_dev *in6_dev;
  	struct net *net = dev_net(dev);
  
  	pinfo = (struct prefix_info *) opt;
  
  	if (len < sizeof(struct prefix_info)) {
  		ADBG("addrconf: prefix option too short\n");
  		return;
  	}
  
  	/*
  	 *	Validation checks ([ADDRCONF], page 19)
  	 */
  
  	addr_type = ipv6_addr_type(&pinfo->prefix);
  
  	if (addr_type & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL))
  		return;
  
  	valid_lft = ntohl(pinfo->valid);
  	prefered_lft = ntohl(pinfo->prefered);
  
  	if (prefered_lft > valid_lft) {
  		net_warn_ratelimited("addrconf: prefix option has invalid lifetime\n");
  		return;
  	}
  
  	in6_dev = in6_dev_get(dev);
  
  	if (!in6_dev) {
  		net_dbg_ratelimited("addrconf: device %s not configured\n",
  				    dev->name);
  		return;
  	}
  
  	/*
  	 *	Two things going on here:
  	 *	1) Add routes for on-link prefixes
  	 *	2) Configure prefixes with the auto flag set
  	 */
  
  	if (pinfo->onlink) {
  		struct rt6_info *rt;
  		unsigned long rt_expires;
  
  		/* Avoid arithmetic overflow. Really, we could
  		 * save rt_expires in seconds, likely valid_lft,
  		 * but it would require division in fib gc, that it
  		 * not good.
  		 */
  		if (HZ > USER_HZ)
  			rt_expires = addrconf_timeout_fixup(valid_lft, HZ);
  		else
  			rt_expires = addrconf_timeout_fixup(valid_lft, USER_HZ);
  
  		if (addrconf_finite_timeout(rt_expires))
  			rt_expires *= HZ;
  
  		rt = addrconf_get_prefix_route(&pinfo->prefix,
  					       pinfo->prefix_len,
  					       dev,
  					       RTF_ADDRCONF | RTF_PREFIX_RT,
  					       RTF_GATEWAY | RTF_DEFAULT);
  
  		if (rt) {
  			/* Autoconf prefix route */
  			if (valid_lft == 0) {
  				ip6_del_rt(rt);
  				rt = NULL;
  			} else if (addrconf_finite_timeout(rt_expires)) {
  				/* not infinity */
  				rt6_set_expires(rt, jiffies + rt_expires);
  			} else {
  				rt6_clean_expires(rt);
  			}
  		} else if (valid_lft) {
  			clock_t expires = 0;
  			int flags = RTF_ADDRCONF | RTF_PREFIX_RT;
  			if (addrconf_finite_timeout(rt_expires)) {
  				/* not infinity */
  				flags |= RTF_EXPIRES;
  				expires = jiffies_to_clock_t(rt_expires);
  			}
  			addrconf_prefix_route(&pinfo->prefix, pinfo->prefix_len,
  					      dev, expires, flags);
  		}
  		ip6_rt_put(rt);
  	}
  
  	/* Try to figure out our local address for this prefix */
  
  	if (pinfo->autoconf && in6_dev->cnf.autoconf) {
  		struct in6_addr addr;
  		bool tokenized = false, dev_addr_generated = false;
  
  		if (pinfo->prefix_len == 64) {
  			memcpy(&addr, &pinfo->prefix, 8);
  
  			if (!ipv6_addr_any(&in6_dev->token)) {
  				read_lock_bh(&in6_dev->lock);
  				memcpy(addr.s6_addr + 8,
  				       in6_dev->token.s6_addr + 8, 8);
  				read_unlock_bh(&in6_dev->lock);
  				tokenized = true;
  			} else if (is_addr_mode_generate_stable(in6_dev) &&
  				   !ipv6_generate_stable_address(&addr, 0,
  								 in6_dev)) {
  				addr_flags |= IFA_F_STABLE_PRIVACY;
  				goto ok;
  			} else if (ipv6_generate_eui64(addr.s6_addr + 8, dev) &&
  				   ipv6_inherit_eui64(addr.s6_addr + 8, in6_dev)) {
  				goto put;
  			} else {
  				dev_addr_generated = true;
  			}
  			goto ok;
  		}
  		net_dbg_ratelimited("IPv6 addrconf: prefix with wrong length %d\n",
  				    pinfo->prefix_len);
  		goto put;
  
  ok:
  		err = addrconf_prefix_rcv_add_addr(net, dev, pinfo, in6_dev,
  						   &addr, addr_type,
  						   addr_flags, sllao,
  						   tokenized, valid_lft,
  						   prefered_lft);
  		if (err)
  			goto put;
  
  		/* Ignore error case here because previous prefix add addr was
  		 * successful which will be notified.
  		 */
  		ndisc_ops_prefix_rcv_add_addr(net, dev, pinfo, in6_dev, &addr,
  					      addr_type, addr_flags, sllao,
  					      tokenized, valid_lft,
  					      prefered_lft,
  					      dev_addr_generated);
  	}
  	inet6_prefix_notify(RTM_NEWPREFIX, in6_dev, pinfo);
  put:
  	in6_dev_put(in6_dev);
  }
  
  /*
   *	Set destination address.
   *	Special case for SIT interfaces where we create a new "virtual"
   *	device.
   */
  int addrconf_set_dstaddr(struct net *net, void __user *arg)
  {
  	struct in6_ifreq ireq;
  	struct net_device *dev;
  	int err = -EINVAL;
  
  	rtnl_lock();
  
  	err = -EFAULT;
  	if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
  		goto err_exit;
  
  	dev = __dev_get_by_index(net, ireq.ifr6_ifindex);
  
  	err = -ENODEV;
  	if (!dev)
  		goto err_exit;
  
  #if IS_ENABLED(CONFIG_IPV6_SIT)
  	if (dev->type == ARPHRD_SIT) {
  		const struct net_device_ops *ops = dev->netdev_ops;
  		struct ifreq ifr;
  		struct ip_tunnel_parm p;
  
  		err = -EADDRNOTAVAIL;
  		if (!(ipv6_addr_type(&ireq.ifr6_addr) & IPV6_ADDR_COMPATv4))
  			goto err_exit;
  
  		memset(&p, 0, sizeof(p));
  		p.iph.daddr = ireq.ifr6_addr.s6_addr32[3];
  		p.iph.saddr = 0;
  		p.iph.version = 4;
  		p.iph.ihl = 5;
  		p.iph.protocol = IPPROTO_IPV6;
  		p.iph.ttl = 64;
  		ifr.ifr_ifru.ifru_data = (__force void __user *)&p;
  
  		if (ops->ndo_do_ioctl) {
  			mm_segment_t oldfs = get_fs();
  
  			set_fs(KERNEL_DS);
  			err = ops->ndo_do_ioctl(dev, &ifr, SIOCADDTUNNEL);
  			set_fs(oldfs);
  		} else
  			err = -EOPNOTSUPP;
  
  		if (err == 0) {
  			err = -ENOBUFS;
  			dev = __dev_get_by_name(net, p.name);
  			if (!dev)
  				goto err_exit;
  			err = dev_open(dev);
  		}
  	}
  #endif
  
  err_exit:
  	rtnl_unlock();
  	return err;
  }
  
  static int ipv6_mc_config(struct sock *sk, bool join,
  			  const struct in6_addr *addr, int ifindex)
  {
  	int ret;
  
  	ASSERT_RTNL();
  
  	lock_sock(sk);
  	if (join)
  		ret = ipv6_sock_mc_join(sk, ifindex, addr);
  	else
  		ret = ipv6_sock_mc_drop(sk, ifindex, addr);
  	release_sock(sk);
  
  	return ret;
  }
  
  /*
   *	Manual configuration of address on an interface
   */
  static int inet6_addr_add(struct net *net, int ifindex,
  			  const struct in6_addr *pfx,
  			  const struct in6_addr *peer_pfx,
  			  unsigned int plen, __u32 ifa_flags,
  			  __u32 prefered_lft, __u32 valid_lft)
  {
  	struct inet6_ifaddr *ifp;
  	struct inet6_dev *idev;
  	struct net_device *dev;
  	unsigned long timeout;
  	clock_t expires;
  	int scope;
  	u32 flags;
  
  	ASSERT_RTNL();
  
  	if (plen > 128)
  		return -EINVAL;
  
  	/* check the lifetime */
  	if (!valid_lft || prefered_lft > valid_lft)
  		return -EINVAL;
  
  	if (ifa_flags & IFA_F_MANAGETEMPADDR && plen != 64)
  		return -EINVAL;
  
  	dev = __dev_get_by_index(net, ifindex);
  	if (!dev)
  		return -ENODEV;
  
  	idev = addrconf_add_dev(dev);
  	if (IS_ERR(idev))
  		return PTR_ERR(idev);
  
  	if (ifa_flags & IFA_F_MCAUTOJOIN) {
  		int ret = ipv6_mc_config(net->ipv6.mc_autojoin_sk,
  					 true, pfx, ifindex);
  
  		if (ret < 0)
  			return ret;
  	}
  
  	scope = ipv6_addr_scope(pfx);
  
  	timeout = addrconf_timeout_fixup(valid_lft, HZ);
  	if (addrconf_finite_timeout(timeout)) {
  		expires = jiffies_to_clock_t(timeout * HZ);
  		valid_lft = timeout;
  		flags = RTF_EXPIRES;
  	} else {
  		expires = 0;
  		flags = 0;
  		ifa_flags |= IFA_F_PERMANENT;
  	}
  
  	timeout = addrconf_timeout_fixup(prefered_lft, HZ);
  	if (addrconf_finite_timeout(timeout)) {
  		if (timeout == 0)
  			ifa_flags |= IFA_F_DEPRECATED;
  		prefered_lft = timeout;
  	}
  
  	ifp = ipv6_add_addr(idev, pfx, peer_pfx, plen, scope, ifa_flags,
  			    valid_lft, prefered_lft);
  
  	if (!IS_ERR(ifp)) {
  		if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) {
  			addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev,
  					      expires, flags);
  		}
  
  		/*
  		 * Note that section 3.1 of RFC 4429 indicates
  		 * that the Optimistic flag should not be set for
  		 * manually configured addresses
  		 */
  		addrconf_dad_start(ifp);
  		if (ifa_flags & IFA_F_MANAGETEMPADDR)
  			manage_tempaddrs(idev, ifp, valid_lft, prefered_lft,
  					 true, jiffies);
  		in6_ifa_put(ifp);
  		addrconf_verify_rtnl();
  		return 0;
  	} else if (ifa_flags & IFA_F_MCAUTOJOIN) {
  		ipv6_mc_config(net->ipv6.mc_autojoin_sk,
  			       false, pfx, ifindex);
  	}
  
  	return PTR_ERR(ifp);
  }
  
  static int inet6_addr_del(struct net *net, int ifindex, u32 ifa_flags,
  			  const struct in6_addr *pfx, unsigned int plen)
  {
  	struct inet6_ifaddr *ifp;
  	struct inet6_dev *idev;
  	struct net_device *dev;
  
  	if (plen > 128)
  		return -EINVAL;
  
  	dev = __dev_get_by_index(net, ifindex);
  	if (!dev)
  		return -ENODEV;
  
  	idev = __in6_dev_get(dev);
  	if (!idev)
  		return -ENXIO;
  
  	read_lock_bh(&idev->lock);
  	list_for_each_entry(ifp, &idev->addr_list, if_list) {
  		if (ifp->prefix_len == plen &&
  		    ipv6_addr_equal(pfx, &ifp->addr)) {
  			in6_ifa_hold(ifp);
  			read_unlock_bh(&idev->lock);
  
  			if (!(ifp->flags & IFA_F_TEMPORARY) &&
  			    (ifa_flags & IFA_F_MANAGETEMPADDR))
  				manage_tempaddrs(idev, ifp, 0, 0, false,
  						 jiffies);
  			ipv6_del_addr(ifp);
  			addrconf_verify_rtnl();
  			if (ipv6_addr_is_multicast(pfx)) {
  				ipv6_mc_config(net->ipv6.mc_autojoin_sk,
  					       false, pfx, dev->ifindex);
  			}
  			return 0;
  		}
  	}
  	read_unlock_bh(&idev->lock);
  	return -EADDRNOTAVAIL;
  }
  
  
  int addrconf_add_ifaddr(struct net *net, void __user *arg)
  {
  	struct in6_ifreq ireq;
  	int err;
  
  	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
  		return -EPERM;
  
  	if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
  		return -EFAULT;
  
  	rtnl_lock();
  	err = inet6_addr_add(net, ireq.ifr6_ifindex, &ireq.ifr6_addr, NULL,
  			     ireq.ifr6_prefixlen, IFA_F_PERMANENT,
  			     INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
  	rtnl_unlock();
  	return err;
  }
  
  int addrconf_del_ifaddr(struct net *net, void __user *arg)
  {
  	struct in6_ifreq ireq;
  	int err;
  
  	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
  		return -EPERM;
  
  	if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
  		return -EFAULT;
  
  	rtnl_lock();
  	err = inet6_addr_del(net, ireq.ifr6_ifindex, 0, &ireq.ifr6_addr,
  			     ireq.ifr6_prefixlen);
  	rtnl_unlock();
  	return err;
  }
  
  static void add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
  		     int plen, int scope)
  {
  	struct inet6_ifaddr *ifp;
  
  	ifp = ipv6_add_addr(idev, addr, NULL, plen,
  			    scope, IFA_F_PERMANENT,
  			    INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
  	if (!IS_ERR(ifp)) {
  		spin_lock_bh(&ifp->lock);
  		ifp->flags &= ~IFA_F_TENTATIVE;
  		spin_unlock_bh(&ifp->lock);
  		rt_genid_bump_ipv6(dev_net(idev->dev));
  		ipv6_ifa_notify(RTM_NEWADDR, ifp);
  		in6_ifa_put(ifp);
  	}
  }
  
  #if IS_ENABLED(CONFIG_IPV6_SIT)
  static void sit_add_v4_addrs(struct inet6_dev *idev)
  {
  	struct in6_addr addr;
  	struct net_device *dev;
  	struct net *net = dev_net(idev->dev);
  	int scope, plen;
  	u32 pflags = 0;
  
  	ASSERT_RTNL();
  
  	memset(&addr, 0, sizeof(struct in6_addr));
  	memcpy(&addr.s6_addr32[3], idev->dev->dev_addr, 4);
  
  	if (idev->dev->flags&IFF_POINTOPOINT) {
  		addr.s6_addr32[0] = htonl(0xfe800000);
  		scope = IFA_LINK;
  		plen = 64;
  	} else {
  		scope = IPV6_ADDR_COMPATv4;
  		plen = 96;
  		pflags |= RTF_NONEXTHOP;
  	}
  
  	if (addr.s6_addr32[3]) {
  		add_addr(idev, &addr, plen, scope);
  		addrconf_prefix_route(&addr, plen, idev->dev, 0, pflags);
  		return;
  	}
  
  	for_each_netdev(net, dev) {
  		struct in_device *in_dev = __in_dev_get_rtnl(dev);
  		if (in_dev && (dev->flags & IFF_UP)) {
  			struct in_ifaddr *ifa;
  
  			int flag = scope;
  
  			for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
  
  				addr.s6_addr32[3] = ifa->ifa_local;
  
  				if (ifa->ifa_scope == RT_SCOPE_LINK)
  					continue;
  				if (ifa->ifa_scope >= RT_SCOPE_HOST) {
  					if (idev->dev->flags&IFF_POINTOPOINT)
  						continue;
  					flag |= IFA_HOST;
  				}
  
  				add_addr(idev, &addr, plen, flag);
  				addrconf_prefix_route(&addr, plen, idev->dev, 0,
  						      pflags);
  			}
  		}
  	}
  }
  #endif
  
  static void init_loopback(struct net_device *dev)
  {
  	struct inet6_dev  *idev;
  
  	/* ::1 */
  
  	ASSERT_RTNL();
  
  	idev = ipv6_find_idev(dev);
  	if (!idev) {
  		pr_debug("%s: add_dev failed\n", __func__);
  		return;
  	}
  
  	add_addr(idev, &in6addr_loopback, 128, IFA_HOST);
  }
  
  void addrconf_add_linklocal(struct inet6_dev *idev,
  			    const struct in6_addr *addr, u32 flags)
  {
  	struct inet6_ifaddr *ifp;
  	u32 addr_flags = flags | IFA_F_PERMANENT;
  
  #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
  	if ((dev_net(idev->dev)->ipv6.devconf_all->optimistic_dad ||
  	     idev->cnf.optimistic_dad) &&
  	    !dev_net(idev->dev)->ipv6.devconf_all->forwarding)
  		addr_flags |= IFA_F_OPTIMISTIC;
  #endif
  
  	ifp = ipv6_add_addr(idev, addr, NULL, 64, IFA_LINK, addr_flags,
  			    INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
  	if (!IS_ERR(ifp)) {
  		addrconf_prefix_route(&ifp->addr, ifp->prefix_len, idev->dev, 0, 0);
  		addrconf_dad_start(ifp);
  		in6_ifa_put(ifp);
  	}
  }
  EXPORT_SYMBOL_GPL(addrconf_add_linklocal);
  
  static bool ipv6_reserved_interfaceid(struct in6_addr address)
  {
  	if ((address.s6_addr32[2] | address.s6_addr32[3]) == 0)
  		return true;
  
  	if (address.s6_addr32[2] == htonl(0x02005eff) &&
  	    ((address.s6_addr32[3] & htonl(0xfe000000)) == htonl(0xfe000000)))
  		return true;
  
  	if (address.s6_addr32[2] == htonl(0xfdffffff) &&
  	    ((address.s6_addr32[3] & htonl(0xffffff80)) == htonl(0xffffff80)))
  		return true;
  
  	return false;
  }
  
  static int ipv6_generate_stable_address(struct in6_addr *address,
  					u8 dad_count,
  					const struct inet6_dev *idev)
  {
  	static DEFINE_SPINLOCK(lock);
  	static __u32 digest[SHA_DIGEST_WORDS];
  	static __u32 workspace[SHA_WORKSPACE_WORDS];
  
  	static union {
  		char __data[SHA_MESSAGE_BYTES];
  		struct {
  			struct in6_addr secret;
  			__be32 prefix[2];
  			unsigned char hwaddr[MAX_ADDR_LEN];
  			u8 dad_count;
  		} __packed;
  	} data;
  
  	struct in6_addr secret;
  	struct in6_addr temp;
  	struct net *net = dev_net(idev->dev);
  
  	BUILD_BUG_ON(sizeof(data.__data) != sizeof(data));
  
  	if (idev->cnf.stable_secret.initialized)
  		secret = idev->cnf.stable_secret.secret;
  	else if (net->ipv6.devconf_dflt->stable_secret.initialized)
  		secret = net->ipv6.devconf_dflt->stable_secret.secret;
  	else
  		return -1;
  
  retry:
  	spin_lock_bh(&lock);
  
  	sha_init(digest);
  	memset(&data, 0, sizeof(data));
  	memset(workspace, 0, sizeof(workspace));
  	memcpy(data.hwaddr, idev->dev->perm_addr, idev->dev->addr_len);
  	data.prefix[0] = address->s6_addr32[0];
  	data.prefix[1] = address->s6_addr32[1];
  	data.secret = secret;
  	data.dad_count = dad_count;
  
  	sha_transform(digest, data.__data, workspace);
  
  	temp = *address;
  	temp.s6_addr32[2] = (__force __be32)digest[0];
  	temp.s6_addr32[3] = (__force __be32)digest[1];
  
  	spin_unlock_bh(&lock);
  
  	if (ipv6_reserved_interfaceid(temp)) {
  		dad_count++;
  		if (dad_count > dev_net(idev->dev)->ipv6.sysctl.idgen_retries)
  			return -1;
  		goto retry;
  	}
  
  	*address = temp;
  	return 0;
  }
  
  static void ipv6_gen_mode_random_init(struct inet6_dev *idev)
  {
  	struct ipv6_stable_secret *s = &idev->cnf.stable_secret;
  
  	if (s->initialized)
  		return;
  	s = &idev->cnf.stable_secret;
  	get_random_bytes(&s->secret, sizeof(s->secret));
  	s->initialized = true;
  }
  
  static void addrconf_addr_gen(struct inet6_dev *idev, bool prefix_route)
  {
  	struct in6_addr addr;
  
  	/* no link local addresses on L3 master devices */
  	if (netif_is_l3_master(idev->dev))
  		return;
  
  	ipv6_addr_set(&addr, htonl(0xFE800000), 0, 0, 0);
  
  	switch (idev->cnf.addr_gen_mode) {
  	case IN6_ADDR_GEN_MODE_RANDOM:
  		ipv6_gen_mode_random_init(idev);
  		/* fallthrough */
  	case IN6_ADDR_GEN_MODE_STABLE_PRIVACY:
  		if (!ipv6_generate_stable_address(&addr, 0, idev))
  			addrconf_add_linklocal(idev, &addr,
  					       IFA_F_STABLE_PRIVACY);
  		else if (prefix_route)
  			addrconf_prefix_route(&addr, 64, idev->dev, 0, 0);
  		break;
  	case IN6_ADDR_GEN_MODE_EUI64:
  		/* addrconf_add_linklocal also adds a prefix_route and we
  		 * only need to care about prefix routes if ipv6_generate_eui64
  		 * couldn't generate one.
  		 */
  		if (ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) == 0)
  			addrconf_add_linklocal(idev, &addr, 0);
  		else if (prefix_route)
  			addrconf_prefix_route(&addr, 64, idev->dev, 0, 0);
  		break;
  	case IN6_ADDR_GEN_MODE_NONE:
  	default:
  		/* will not add any link local address */
  		break;
  	}
  }
  
  static void addrconf_dev_config(struct net_device *dev)
  {
  	struct inet6_dev *idev;
  
  	ASSERT_RTNL();
  
  	if ((dev->type != ARPHRD_ETHER) &&
  	    (dev->type != ARPHRD_FDDI) &&
  	    (dev->type != ARPHRD_ARCNET) &&
  	    (dev->type != ARPHRD_INFINIBAND) &&
  	    (dev->type != ARPHRD_IEEE1394) &&
  	    (dev->type != ARPHRD_TUNNEL6) &&
  	    (dev->type != ARPHRD_6LOWPAN) &&
  	    (dev->type != ARPHRD_IP6GRE) &&
  	    (dev->type != ARPHRD_IPGRE) &&
  	    (dev->type != ARPHRD_TUNNEL) &&
  	    (dev->type != ARPHRD_NONE)) {
  		/* Alas, we support only Ethernet autoconfiguration. */
  		idev = __in6_dev_get(dev);
  		if (!IS_ERR_OR_NULL(idev) && dev->flags & IFF_UP &&
  					dev->flags & IFF_MULTICAST)
  		  ipv6_mc_up(idev);
  		return;
  	}
  
  	idev = addrconf_add_dev(dev);
  	if (IS_ERR(idev))
  		return;
  
  	/* this device type has no EUI support */
  	if (dev->type == ARPHRD_NONE &&
  	    idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_EUI64)
  		idev->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_RANDOM;
  
  	addrconf_addr_gen(idev, false);
  }
  
  #if IS_ENABLED(CONFIG_IPV6_SIT)
  static void addrconf_sit_config(struct net_device *dev)
  {
  	struct inet6_dev *idev;
  
  	ASSERT_RTNL();
  
  	/*
  	 * Configure the tunnel with one of our IPv4
  	 * addresses... we should configure all of
  	 * our v4 addrs in the tunnel
  	 */
  
  	idev = ipv6_find_idev(dev);
  	if (!idev) {
  		pr_debug("%s: add_dev failed\n", __func__);
  		return;
  	}
  
  	if (dev->priv_flags & IFF_ISATAP) {
  		addrconf_addr_gen(idev, false);
  		return;
  	}
  
  	sit_add_v4_addrs(idev);
  
  	if (dev->flags&IFF_POINTOPOINT)
  		addrconf_add_mroute(dev);
  }
  #endif
  
  #if IS_ENABLED(CONFIG_NET_IPGRE)
  static void addrconf_gre_config(struct net_device *dev)
  {
  	struct inet6_dev *idev;
  
  	ASSERT_RTNL();
  
  	idev = ipv6_find_idev(dev);
  	if (!idev) {
  		pr_debug("%s: add_dev failed\n", __func__);
  		return;
  	}
  
  	addrconf_addr_gen(idev, true);
  	if (dev->flags & IFF_POINTOPOINT)
  		addrconf_add_mroute(dev);
  }
  #endif
  
  static int fixup_permanent_addr(struct inet6_dev *idev,
  				struct inet6_ifaddr *ifp)
  {
  	/* !rt6i_node means the host route was removed from the
  	 * FIB, for example, if 'lo' device is taken down. In that
  	 * case regenerate the host route.
  	 */
  	if (!ifp->rt || !ifp->rt->rt6i_node) {
  		struct rt6_info *rt, *prev;
  
  		rt = addrconf_dst_alloc(idev, &ifp->addr, false);
  		if (unlikely(IS_ERR(rt)))
  			return PTR_ERR(rt);
  
  		/* ifp->rt can be accessed outside of rtnl */
  		spin_lock(&ifp->lock);
  		prev = ifp->rt;
  		ifp->rt = rt;
  		spin_unlock(&ifp->lock);
  
  		ip6_rt_put(prev);
  	}
  
  	if (!(ifp->flags & IFA_F_NOPREFIXROUTE)) {
  		addrconf_prefix_route(&ifp->addr, ifp->prefix_len,
  				      idev->dev, 0, 0);
  	}
  
  	if (ifp->state == INET6_IFADDR_STATE_PREDAD)
  		addrconf_dad_start(ifp);
  
  	return 0;
  }
  
  static void addrconf_permanent_addr(struct net_device *dev)
  {
  	struct inet6_ifaddr *ifp, *tmp;
  	struct inet6_dev *idev;
  
  	idev = __in6_dev_get(dev);
  	if (!idev)
  		return;
  
  	write_lock_bh(&idev->lock);
  
  	list_for_each_entry_safe(ifp, tmp, &idev->addr_list, if_list) {
  		if ((ifp->flags & IFA_F_PERMANENT) &&
  		    fixup_permanent_addr(idev, ifp) < 0) {
  			write_unlock_bh(&idev->lock);
  			in6_ifa_hold(ifp);
  			ipv6_del_addr(ifp);
  			write_lock_bh(&idev->lock);
  
  			net_info_ratelimited("%s: Failed to add prefix route for address %pI6c; dropping\n",
  					     idev->dev->name, &ifp->addr);
  		}
  	}
  
  	write_unlock_bh(&idev->lock);
  }
  
  static int addrconf_notify(struct notifier_block *this, unsigned long event,
  			   void *ptr)
  {
  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
  	struct netdev_notifier_changeupper_info *info;
  	struct inet6_dev *idev = __in6_dev_get(dev);
  	struct net *net = dev_net(dev);
  	int run_pending = 0;
  	int err;
  
  	switch (event) {
  	case NETDEV_REGISTER:
  		if (!idev && dev->mtu >= IPV6_MIN_MTU) {
  			idev = ipv6_add_dev(dev);
  			if (IS_ERR(idev))
  				return notifier_from_errno(PTR_ERR(idev));
  		}
  		break;
  
  	case NETDEV_CHANGEMTU:
  		/* if MTU under IPV6_MIN_MTU stop IPv6 on this interface. */
  		if (dev->mtu < IPV6_MIN_MTU) {
  			addrconf_ifdown(dev, dev != net->loopback_dev);
  			break;
  		}
  
  		if (idev) {
  			rt6_mtu_change(dev, dev->mtu);
  			idev->cnf.mtu6 = dev->mtu;
  			break;
  		}
  
  		/* allocate new idev */
  		idev = ipv6_add_dev(dev);
  		if (IS_ERR(idev))
  			break;
  
  		/* device is still not ready */
  		if (!(idev->if_flags & IF_READY))
  			break;
  
  		run_pending = 1;
  
  		/* fall through */
  
  	case NETDEV_UP:
  	case NETDEV_CHANGE:
  		if (dev->flags & IFF_SLAVE)
  			break;
  
  		if (idev && idev->cnf.disable_ipv6)
  			break;
  
  		if (event == NETDEV_UP) {
  			/* restore routes for permanent addresses */
  			addrconf_permanent_addr(dev);
  
  			if (!addrconf_link_ready(dev)) {
  				/* device is not ready yet. */
  				pr_info("ADDRCONF(NETDEV_UP): %s: link is not ready\n",
  					dev->name);
  				break;
  			}
  
  			if (!idev && dev->mtu >= IPV6_MIN_MTU)
  				idev = ipv6_add_dev(dev);
  
  			if (!IS_ERR_OR_NULL(idev)) {
  				idev->if_flags |= IF_READY;
  				run_pending = 1;
  			}
  		} else if (event == NETDEV_CHANGE) {
  			if (!addrconf_link_ready(dev)) {
  				/* device is still not ready. */
  				break;
  			}
  
  			if (idev) {
  				if (idev->if_flags & IF_READY) {
  					/* device is already configured -
  					 * but resend MLD reports, we might
  					 * have roamed and need to update
  					 * multicast snooping switches
  					 */
  					ipv6_mc_up(idev);
  					break;
  				}
  				idev->if_flags |= IF_READY;
  			}
  
  			pr_info("ADDRCONF(NETDEV_CHANGE): %s: link becomes ready\n",
  				dev->name);
  
  			run_pending = 1;
  		}
  
  		switch (dev->type) {
  #if IS_ENABLED(CONFIG_IPV6_SIT)
  		case ARPHRD_SIT:
  			addrconf_sit_config(dev);
  			break;
  #endif
  #if IS_ENABLED(CONFIG_NET_IPGRE)
  		case ARPHRD_IPGRE:
  			addrconf_gre_config(dev);
  			break;
  #endif
  		case ARPHRD_LOOPBACK:
  			init_loopback(dev);
  			break;
  
  		default:
  			addrconf_dev_config(dev);
  			break;
  		}
  
  		if (!IS_ERR_OR_NULL(idev)) {
  			if (run_pending)
  				addrconf_dad_run(idev);
  
  			/*
  			 * If the MTU changed during the interface down,
  			 * when the interface up, the changed MTU must be
  			 * reflected in the idev as well as routers.
  			 */
  			if (idev->cnf.mtu6 != dev->mtu &&
  			    dev->mtu >= IPV6_MIN_MTU) {
  				rt6_mtu_change(dev, dev->mtu);
  				idev->cnf.mtu6 = dev->mtu;
  			}
  			idev->tstamp = jiffies;
  			inet6_ifinfo_notify(RTM_NEWLINK, idev);
  
  			/*
  			 * If the changed mtu during down is lower than
  			 * IPV6_MIN_MTU stop IPv6 on this interface.
  			 */
  			if (dev->mtu < IPV6_MIN_MTU)
  				addrconf_ifdown(dev, dev != net->loopback_dev);
  		}
  		break;
  
  	case NETDEV_DOWN:
  	case NETDEV_UNREGISTER:
  		/*
  		 *	Remove all addresses from this interface.
  		 */
  		addrconf_ifdown(dev, event != NETDEV_DOWN);
  		break;
  
  	case NETDEV_CHANGENAME:
  		if (idev) {
  			snmp6_unregister_dev(idev);
  			addrconf_sysctl_unregister(idev);
  			err = addrconf_sysctl_register(idev);
  			if (err)
  				return notifier_from_errno(err);
  			err = snmp6_register_dev(idev);
  			if (err) {
  				addrconf_sysctl_unregister(idev);
  				return notifier_from_errno(err);
  			}
  		}
  		break;
  
  	case NETDEV_PRE_TYPE_CHANGE:
  	case NETDEV_POST_TYPE_CHANGE:
  		if (idev)
  			addrconf_type_change(dev, event);
  		break;
  
  	case NETDEV_CHANGEUPPER:
  		info = ptr;
  
  		/* flush all routes if dev is linked to or unlinked from
  		 * an L3 master device (e.g., VRF)
  		 */
  		if (info->upper_dev && netif_is_l3_master(info->upper_dev))
  			addrconf_ifdown(dev, 0);
  	}
  
  	return NOTIFY_OK;
  }
  
  /*
   *	addrconf module should be notified of a device going up
   */
  static struct notifier_block ipv6_dev_notf = {
  	.notifier_call = addrconf_notify,
  	.priority = ADDRCONF_NOTIFY_PRIORITY,
  };
  
  static void addrconf_type_change(struct net_device *dev, unsigned long event)
  {
  	struct inet6_dev *idev;
  	ASSERT_RTNL();
  
  	idev = __in6_dev_get(dev);
  
  	if (event == NETDEV_POST_TYPE_CHANGE)
  		ipv6_mc_remap(idev);
  	else if (event == NETDEV_PRE_TYPE_CHANGE)
  		ipv6_mc_unmap(idev);
  }
  
  static bool addr_is_local(const struct in6_addr *addr)
  {
  	return ipv6_addr_type(addr) &
  		(IPV6_ADDR_LINKLOCAL | IPV6_ADDR_LOOPBACK);
  }
  
  static int addrconf_ifdown(struct net_device *dev, int how)
  {
  	struct net *net = dev_net(dev);
  	struct inet6_dev *idev;
  	struct inet6_ifaddr *ifa, *tmp;
  	struct list_head del_list;
  	int _keep_addr;
  	bool keep_addr;
  	int state, i;
  
  	ASSERT_RTNL();
  
  	rt6_ifdown(net, dev);
  	neigh_ifdown(&nd_tbl, dev);
  
  	idev = __in6_dev_get(dev);
  	if (!idev)
  		return -ENODEV;
  
  	/*
  	 * Step 1: remove reference to ipv6 device from parent device.
  	 *	   Do not dev_put!
  	 */
  	if (how) {
  		idev->dead = 1;
  
  		/* protected by rtnl_lock */
  		RCU_INIT_POINTER(dev->ip6_ptr, NULL);
  
  		/* Step 1.5: remove snmp6 entry */
  		snmp6_unregister_dev(idev);
  
  	}
  
  	/* aggregate the system setting and interface setting */
  	_keep_addr = net->ipv6.devconf_all->keep_addr_on_down;
  	if (!_keep_addr)
  		_keep_addr = idev->cnf.keep_addr_on_down;
  
  	/* combine the user config with event to determine if permanent
  	 * addresses are to be removed from address hash table
  	 */
  	keep_addr = !(how || _keep_addr <= 0 || idev->cnf.disable_ipv6);
  
  	/* Step 2: clear hash table */
  	for (i = 0; i < IN6_ADDR_HSIZE; i++) {
  		struct hlist_head *h = &inet6_addr_lst[i];
  
  		spin_lock_bh(&addrconf_hash_lock);
  restart:
  		hlist_for_each_entry_rcu(ifa, h, addr_lst) {
  			if (ifa->idev == idev) {
  				addrconf_del_dad_work(ifa);
  				/* combined flag + permanent flag decide if
  				 * address is retained on a down event
  				 */
  				if (!keep_addr ||
  				    !(ifa->flags & IFA_F_PERMANENT) ||
  				    addr_is_local(&ifa->addr)) {
  					hlist_del_init_rcu(&ifa->addr_lst);
  					goto restart;
  				}
  			}
  		}
  		spin_unlock_bh(&addrconf_hash_lock);
  	}
  
  	write_lock_bh(&idev->lock);
  
  	addrconf_del_rs_timer(idev);
  
  	/* Step 2: clear flags for stateless addrconf */
  	if (!how)
  		idev->if_flags &= ~(IF_RS_SENT|IF_RA_RCVD|IF_READY);
  
  	/* Step 3: clear tempaddr list */
  	while (!list_empty(&idev->tempaddr_list)) {
  		ifa = list_first_entry(&idev->tempaddr_list,
  				       struct inet6_ifaddr, tmp_list);
  		list_del(&ifa->tmp_list);
  		write_unlock_bh(&idev->lock);
  		spin_lock_bh(&ifa->lock);
  
  		if (ifa->ifpub) {
  			in6_ifa_put(ifa->ifpub);
  			ifa->ifpub = NULL;
  		}
  		spin_unlock_bh(&ifa->lock);
  		in6_ifa_put(ifa);
  		write_lock_bh(&idev->lock);
  	}
  
  	/* re-combine the user config with event to determine if permanent
  	 * addresses are to be removed from the interface list
  	 */
  	keep_addr = (!how && _keep_addr > 0 && !idev->cnf.disable_ipv6);
  
  	INIT_LIST_HEAD(&del_list);
  	list_for_each_entry_safe(ifa, tmp, &idev->addr_list, if_list) {
  		struct rt6_info *rt = NULL;
  		bool keep;
  
  		addrconf_del_dad_work(ifa);
  
  		keep = keep_addr && (ifa->flags & IFA_F_PERMANENT) &&
  			!addr_is_local(&ifa->addr);
  		if (!keep)
  			list_move(&ifa->if_list, &del_list);
  
  		write_unlock_bh(&idev->lock);
  		spin_lock_bh(&ifa->lock);
  
  		if (keep) {
  			/* set state to skip the notifier below */
  			state = INET6_IFADDR_STATE_DEAD;
  			ifa->state = INET6_IFADDR_STATE_PREDAD;
  			if (!(ifa->flags & IFA_F_NODAD))
  				ifa->flags |= IFA_F_TENTATIVE;
  
  			rt = ifa->rt;
  			ifa->rt = NULL;
  		} else {
  			state = ifa->state;
  			ifa->state = INET6_IFADDR_STATE_DEAD;
  		}
  
  		spin_unlock_bh(&ifa->lock);
  
  		if (rt)
  			ip6_del_rt(rt);
  
  		if (state != INET6_IFADDR_STATE_DEAD) {
  			__ipv6_ifa_notify(RTM_DELADDR, ifa);
  			inet6addr_notifier_call_chain(NETDEV_DOWN, ifa);
  		} else {
  			if (idev->cnf.forwarding)
  				addrconf_leave_anycast(ifa);
  			addrconf_leave_solict(ifa->idev, &ifa->addr);
  		}
  
  		write_lock_bh(&idev->lock);
  	}
  
  	write_unlock_bh(&idev->lock);
  
  	/* now clean up addresses to be removed */
  	while (!list_empty(&del_list)) {
  		ifa = list_first_entry(&del_list,
  				       struct inet6_ifaddr, if_list);
  		list_del(&ifa->if_list);
  
  		in6_ifa_put(ifa);
  	}
  
  	/* Step 5: Discard anycast and multicast list */
  	if (how) {
  		ipv6_ac_destroy_dev(idev);
  		ipv6_mc_destroy_dev(idev);
  	} else {
  		ipv6_mc_down(idev);
  	}
  
  	idev->tstamp = jiffies;
  
  	/* Last: Shot the device (if unregistered) */
  	if (how) {
  		addrconf_sysctl_unregister(idev);
  		neigh_parms_release(&nd_tbl, idev->nd_parms);
  		neigh_ifdown(&nd_tbl, dev);
  		in6_dev_put(idev);
  	}
  	return 0;
  }
  
  static void addrconf_rs_timer(unsigned long data)
  {
  	struct inet6_dev *idev = (struct inet6_dev *)data;
  	struct net_device *dev = idev->dev;
  	struct in6_addr lladdr;
  
  	write_lock(&idev->lock);
  	if (idev->dead || !(idev->if_flags & IF_READY))
  		goto out;
  
  	if (!ipv6_accept_ra(idev))
  		goto out;
  
  	/* Announcement received after solicitation was sent */
  	if (idev->if_flags & IF_RA_RCVD)
  		goto out;
  
  	if (idev->rs_probes++ < idev->cnf.rtr_solicits || idev->cnf.rtr_solicits < 0) {
  		write_unlock(&idev->lock);
  		if (!ipv6_get_lladdr(dev, &lladdr, IFA_F_TENTATIVE))
  			ndisc_send_rs(dev, &lladdr,
  				      &in6addr_linklocal_allrouters);
  		else
  			goto put;
  
  		write_lock(&idev->lock);
  		idev->rs_interval = rfc3315_s14_backoff_update(
  			idev->rs_interval, idev->cnf.rtr_solicit_max_interval);
  		/* The wait after the last probe can be shorter */
  		addrconf_mod_rs_timer(idev, (idev->rs_probes ==
  					     idev->cnf.rtr_solicits) ?
  				      idev->cnf.rtr_solicit_delay :
  				      idev->rs_interval);
  	} else {
  		/*
  		 * Note: we do not support deprecated "all on-link"
  		 * assumption any longer.
  		 */
  		pr_debug("%s: no IPv6 routers present\n", idev->dev->name);
  	}
  
  out:
  	write_unlock(&idev->lock);
  put:
  	in6_dev_put(idev);
  }
  
  /*
   *	Duplicate Address Detection
   */
  static void addrconf_dad_kick(struct inet6_ifaddr *ifp)
  {
  	unsigned long rand_num;
  	struct inet6_dev *idev = ifp->idev;
  	u64 nonce;
  
  	if (ifp->flags & IFA_F_OPTIMISTIC)
  		rand_num = 0;
  	else
  		rand_num = prandom_u32() % (idev->cnf.rtr_solicit_delay ? : 1);
  
  	nonce = 0;
  	if (idev->cnf.enhanced_dad ||
  	    dev_net(idev->dev)->ipv6.devconf_all->enhanced_dad) {
  		do
  			get_random_bytes(&nonce, 6);
  		while (nonce == 0);
  	}
  	ifp->dad_nonce = nonce;
  	ifp->dad_probes = idev->cnf.dad_transmits;
  	addrconf_mod_dad_work(ifp, rand_num);
  }
  
  static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
  {
  	struct inet6_dev *idev = ifp->idev;
  	struct net_device *dev = idev->dev;
  	bool bump_id, notify = false;
  
  	addrconf_join_solict(dev, &ifp->addr);
  
  	prandom_seed((__force u32) ifp->addr.s6_addr32[3]);
  
  	read_lock_bh(&idev->lock);
  	spin_lock(&ifp->lock);
  	if (ifp->state == INET6_IFADDR_STATE_DEAD)
  		goto out;
  
  	if (dev->flags&(IFF_NOARP|IFF_LOOPBACK) ||
  	    (dev_net(dev)->ipv6.devconf_all->accept_dad < 1 &&
  	     idev->cnf.accept_dad < 1) ||
  	    !(ifp->flags&IFA_F_TENTATIVE) ||
  	    ifp->flags & IFA_F_NODAD) {
  		bool send_na = false;
  
  		if (ifp->flags & IFA_F_TENTATIVE &&
  		    !(ifp->flags & IFA_F_OPTIMISTIC))
  			send_na = true;
  		bump_id = ifp->flags & IFA_F_TENTATIVE;
  		ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);
  		spin_unlock(&ifp->lock);
  		read_unlock_bh(&idev->lock);
  
  		addrconf_dad_completed(ifp, bump_id, send_na);
  		return;
  	}
  
  	if (!(idev->if_flags & IF_READY)) {
  		spin_unlock(&ifp->lock);
  		read_unlock_bh(&idev->lock);
  		/*
  		 * If the device is not ready:
  		 * - keep it tentative if it is a permanent address.
  		 * - otherwise, kill it.
  		 */
  		in6_ifa_hold(ifp);
  		addrconf_dad_stop(ifp, 0);
  		return;
  	}
  
  	/*
  	 * Optimistic nodes can start receiving
  	 * Frames right away
  	 */
  	if (ifp->flags & IFA_F_OPTIMISTIC) {
  		ip6_ins_rt(ifp->rt);
  		if (ipv6_use_optimistic_addr(dev_net(dev), idev)) {
  			/* Because optimistic nodes can use this address,
  			 * notify listeners. If DAD fails, RTM_DELADDR is sent.
  			 */
  			notify = true;
  		}
  	}
  
  	addrconf_dad_kick(ifp);
  out:
  	spin_unlock(&ifp->lock);
  	read_unlock_bh(&idev->lock);
  	if (notify)
  		ipv6_ifa_notify(RTM_NEWADDR, ifp);
  }
  
  static void addrconf_dad_start(struct inet6_ifaddr *ifp)
  {
  	bool begin_dad = false;
  
  	spin_lock_bh(&ifp->lock);
  	if (ifp->state != INET6_IFADDR_STATE_DEAD) {
  		ifp->state = INET6_IFADDR_STATE_PREDAD;
  		begin_dad = true;
  	}
  	spin_unlock_bh(&ifp->lock);
  
  	if (begin_dad)
  		addrconf_mod_dad_work(ifp, 0);
  }
  
  static void addrconf_dad_work(struct work_struct *w)
  {
  	struct inet6_ifaddr *ifp = container_of(to_delayed_work(w),
  						struct inet6_ifaddr,
  						dad_work);
  	struct inet6_dev *idev = ifp->idev;
  	bool bump_id, disable_ipv6 = false;
  	struct in6_addr mcaddr;
  
  	enum {
  		DAD_PROCESS,
  		DAD_BEGIN,
  		DAD_ABORT,
  	} action = DAD_PROCESS;
  
  	rtnl_lock();
  
  	spin_lock_bh(&ifp->lock);
  	if (ifp->state == INET6_IFADDR_STATE_PREDAD) {
  		action = DAD_BEGIN;
  		ifp->state = INET6_IFADDR_STATE_DAD;
  	} else if (ifp->state == INET6_IFADDR_STATE_ERRDAD) {
  		action = DAD_ABORT;
  		ifp->state = INET6_IFADDR_STATE_POSTDAD;
  
  		if ((dev_net(idev->dev)->ipv6.devconf_all->accept_dad > 1 ||
  		     idev->cnf.accept_dad > 1) &&
  		    !idev->cnf.disable_ipv6 &&
  		    !(ifp->flags & IFA_F_STABLE_PRIVACY)) {
  			struct in6_addr addr;
  
  			addr.s6_addr32[0] = htonl(0xfe800000);
  			addr.s6_addr32[1] = 0;
  
  			if (!ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) &&
  			    ipv6_addr_equal(&ifp->addr, &addr)) {
  				/* DAD failed for link-local based on MAC */
  				idev->cnf.disable_ipv6 = 1;
  
  				pr_info("%s: IPv6 being disabled!\n",
  					ifp->idev->dev->name);
  				disable_ipv6 = true;
  			}
  		}
  	}
  	spin_unlock_bh(&ifp->lock);
  
  	if (action == DAD_BEGIN) {
  		addrconf_dad_begin(ifp);
  		goto out;
  	} else if (action == DAD_ABORT) {
  		in6_ifa_hold(ifp);
  		addrconf_dad_stop(ifp, 1);
  		if (disable_ipv6)
  			addrconf_ifdown(idev->dev, 0);
  		goto out;
  	}
  
  	if (!ifp->dad_probes && addrconf_dad_end(ifp))
  		goto out;
  
  	write_lock_bh(&idev->lock);
  	if (idev->dead || !(idev->if_flags & IF_READY)) {
  		write_unlock_bh(&idev->lock);
  		goto out;
  	}
  
  	spin_lock(&ifp->lock);
  	if (ifp->state == INET6_IFADDR_STATE_DEAD) {
  		spin_unlock(&ifp->lock);
  		write_unlock_bh(&idev->lock);
  		goto out;
  	}
  
  	if (ifp->dad_probes == 0) {
  		bool send_na = false;
  
  		/*
  		 * DAD was successful
  		 */
  
  		if (ifp->flags & IFA_F_TENTATIVE &&
  		    !(ifp->flags & IFA_F_OPTIMISTIC))
  			send_na = true;
  		bump_id = ifp->flags & IFA_F_TENTATIVE;
  		ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);
  		spin_unlock(&ifp->lock);
  		write_unlock_bh(&idev->lock);
  
  		addrconf_dad_completed(ifp, bump_id, send_na);
  
  		goto out;
  	}
  
  	ifp->dad_probes--;
  	addrconf_mod_dad_work(ifp,
  			      NEIGH_VAR(ifp->idev->nd_parms, RETRANS_TIME));
  	spin_unlock(&ifp->lock);
  	write_unlock_bh(&idev->lock);
  
  	/* send a neighbour solicitation for our addr */
  	addrconf_addr_solict_mult(&ifp->addr, &mcaddr);
  	ndisc_send_ns(ifp->idev->dev, &ifp->addr, &mcaddr, &in6addr_any,
  		      ifp->dad_nonce);
  out:
  	in6_ifa_put(ifp);
  	rtnl_unlock();
  }
  
  /* ifp->idev must be at least read locked */
  static bool ipv6_lonely_lladdr(struct inet6_ifaddr *ifp)
  {
  	struct inet6_ifaddr *ifpiter;
  	struct inet6_dev *idev = ifp->idev;
  
  	list_for_each_entry_reverse(ifpiter, &idev->addr_list, if_list) {
  		if (ifpiter->scope > IFA_LINK)
  			break;
  		if (ifp != ifpiter && ifpiter->scope == IFA_LINK &&
  		    (ifpiter->flags & (IFA_F_PERMANENT|IFA_F_TENTATIVE|
  				       IFA_F_OPTIMISTIC|IFA_F_DADFAILED)) ==
  		    IFA_F_PERMANENT)
  			return false;
  	}
  	return true;
  }
  
  static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id,
  				   bool send_na)
  {
  	struct net_device *dev = ifp->idev->dev;
  	struct in6_addr lladdr;
  	bool send_rs, send_mld;
  
  	addrconf_del_dad_work(ifp);
  
  	/*
  	 *	Configure the address for reception. Now it is valid.
  	 */
  
  	ipv6_ifa_notify(RTM_NEWADDR, ifp);
  
  	/* If added prefix is link local and we are prepared to process
  	   router advertisements, start sending router solicitations.
  	 */
  
  	read_lock_bh(&ifp->idev->lock);
  	send_mld = ifp->scope == IFA_LINK && ipv6_lonely_lladdr(ifp);
  	send_rs = send_mld &&
  		  ipv6_accept_ra(ifp->idev) &&
  		  ifp->idev->cnf.rtr_solicits != 0 &&
  		  (dev->flags&IFF_LOOPBACK) == 0;
  	read_unlock_bh(&ifp->idev->lock);
  
  	/* While dad is in progress mld report's source address is in6_addrany.
  	 * Resend with proper ll now.
  	 */
  	if (send_mld)
  		ipv6_mc_dad_complete(ifp->idev);
  
  	/* send unsolicited NA if enabled */
  	if (send_na &&
  	    (ifp->idev->cnf.ndisc_notify ||
  	     dev_net(dev)->ipv6.devconf_all->ndisc_notify)) {
  		ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifp->addr,
  			      /*router=*/ !!ifp->idev->cnf.forwarding,
  			      /*solicited=*/ false, /*override=*/ true,
  			      /*inc_opt=*/ true);
  	}
  
  	if (send_rs) {
  		/*
  		 *	If a host as already performed a random delay
  		 *	[...] as part of DAD [...] there is no need
  		 *	to delay again before sending the first RS
  		 */
  		if (ipv6_get_lladdr(dev, &lladdr, IFA_F_TENTATIVE))
  			return;
  		ndisc_send_rs(dev, &lladdr, &in6addr_linklocal_allrouters);
  
  		write_lock_bh(&ifp->idev->lock);
  		spin_lock(&ifp->lock);
  		ifp->idev->rs_interval = rfc3315_s14_backoff_init(
  			ifp->idev->cnf.rtr_solicit_interval);
  		ifp->idev->rs_probes = 1;
  		ifp->idev->if_flags |= IF_RS_SENT;
  		addrconf_mod_rs_timer(ifp->idev, ifp->idev->rs_interval);
  		spin_unlock(&ifp->lock);
  		write_unlock_bh(&ifp->idev->lock);
  	}
  
  	if (bump_id)
  		rt_genid_bump_ipv6(dev_net(dev));
  
  	/* Make sure that a new temporary address will be created
  	 * before this temporary address becomes deprecated.
  	 */
  	if (ifp->flags & IFA_F_TEMPORARY)
  		addrconf_verify_rtnl();
  }
  
  static void addrconf_dad_run(struct inet6_dev *idev)
  {
  	struct inet6_ifaddr *ifp;
  
  	read_lock_bh(&idev->lock);
  	list_for_each_entry(ifp, &idev->addr_list, if_list) {
  		spin_lock(&ifp->lock);
  		if (ifp->flags & IFA_F_TENTATIVE &&
  		    ifp->state == INET6_IFADDR_STATE_DAD)
  			addrconf_dad_kick(ifp);
  		spin_unlock(&ifp->lock);
  	}
  	read_unlock_bh(&idev->lock);
  }
  
  #ifdef CONFIG_PROC_FS
  struct if6_iter_state {
  	struct seq_net_private p;
  	int bucket;
  	int offset;
  };
  
  static struct inet6_ifaddr *if6_get_first(struct seq_file *seq, loff_t pos)
  {
  	struct inet6_ifaddr *ifa = NULL;
  	struct if6_iter_state *state = seq->private;
  	struct net *net = seq_file_net(seq);
  	int p = 0;
  
  	/* initial bucket if pos is 0 */
  	if (pos == 0) {
  		state->bucket = 0;
  		state->offset = 0;
  	}
  
  	for (; state->bucket < IN6_ADDR_HSIZE; ++state->bucket) {
  		hlist_for_each_entry_rcu_bh(ifa, &inet6_addr_lst[state->bucket],
  					 addr_lst) {
  			if (!net_eq(dev_net(ifa->idev->dev), net))
  				continue;
  			/* sync with offset */
  			if (p < state->offset) {
  				p++;
  				continue;
  			}
  			return ifa;
  		}
  
  		/* prepare for next bucket */
  		state->offset = 0;
  		p = 0;
  	}
  	return NULL;
  }
  
  static struct inet6_ifaddr *if6_get_next(struct seq_file *seq,
  					 struct inet6_ifaddr *ifa)
  {
  	struct if6_iter_state *state = seq->private;
  	struct net *net = seq_file_net(seq);
  
  	hlist_for_each_entry_continue_rcu_bh(ifa, addr_lst) {
  		if (!net_eq(dev_net(ifa->idev->dev), net))
  			continue;
  		state->offset++;
  		return ifa;
  	}
  
  	state->offset = 0;
  	while (++state->bucket < IN6_ADDR_HSIZE) {
  		hlist_for_each_entry_rcu_bh(ifa,
  				     &inet6_addr_lst[state->bucket], addr_lst) {
  			if (!net_eq(dev_net(ifa->idev->dev), net))
  				continue;
  			return ifa;
  		}
  	}
  
  	return NULL;
  }
  
  static void *if6_seq_start(struct seq_file *seq, loff_t *pos)
  	__acquires(rcu_bh)
  {
  	rcu_read_lock_bh();
  	return if6_get_first(seq, *pos);
  }
  
  static void *if6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	struct inet6_ifaddr *ifa;
  
  	ifa = if6_get_next(seq, v);
  	++*pos;
  	return ifa;
  }
  
  static void if6_seq_stop(struct seq_file *seq, void *v)
  	__releases(rcu_bh)
  {
  	rcu_read_unlock_bh();
  }
  
  static int if6_seq_show(struct seq_file *seq, void *v)
  {
  	struct inet6_ifaddr *ifp = (struct inet6_ifaddr *)v;
  	seq_printf(seq, "%pi6 %02x %02x %02x %02x %8s\n",
  		   &ifp->addr,
  		   ifp->idev->dev->ifindex,
  		   ifp->prefix_len,
  		   ifp->scope,
  		   (u8) ifp->flags,
  		   ifp->idev->dev->name);
  	return 0;
  }
  
  static const struct seq_operations if6_seq_ops = {
  	.start	= if6_seq_start,
  	.next	= if6_seq_next,
  	.show	= if6_seq_show,
  	.stop	= if6_seq_stop,
  };
  
  static int if6_seq_open(struct inode *inode, struct file *file)
  {
  	return seq_open_net(inode, file, &if6_seq_ops,
  			    sizeof(struct if6_iter_state));
  }
  
  static const struct file_operations if6_fops = {
  	.owner		= THIS_MODULE,
  	.open		= if6_seq_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= seq_release_net,
  };
  
  static int __net_init if6_proc_net_init(struct net *net)
  {
  	if (!proc_create("if_inet6", S_IRUGO, net->proc_net, &if6_fops))
  		return -ENOMEM;
  	return 0;
  }
  
  static void __net_exit if6_proc_net_exit(struct net *net)
  {
  	remove_proc_entry("if_inet6", net->proc_net);
  }
  
  static struct pernet_operations if6_proc_net_ops = {
  	.init = if6_proc_net_init,
  	.exit = if6_proc_net_exit,
  };
  
  int __init if6_proc_init(void)
  {
  	return register_pernet_subsys(&if6_proc_net_ops);
  }
  
  void if6_proc_exit(void)
  {
  	unregister_pernet_subsys(&if6_proc_net_ops);
  }
  #endif	/* CONFIG_PROC_FS */
  
  #if IS_ENABLED(CONFIG_IPV6_MIP6)
  /* Check if address is a home address configured on any interface. */
  int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr)
  {
  	int ret = 0;
  	struct inet6_ifaddr *ifp = NULL;
  	unsigned int hash = inet6_addr_hash(addr);
  
  	rcu_read_lock_bh();
  	hlist_for_each_entry_rcu_bh(ifp, &inet6_addr_lst[hash], addr_lst) {
  		if (!net_eq(dev_net(ifp->idev->dev), net))
  			continue;
  		if (ipv6_addr_equal(&ifp->addr, addr) &&
  		    (ifp->flags & IFA_F_HOMEADDRESS)) {
  			ret = 1;
  			break;
  		}
  	}
  	rcu_read_unlock_bh();
  	return ret;
  }
  #endif
  
  /*
   *	Periodic address status verification
   */
  
  static void addrconf_verify_rtnl(void)
  {
  	unsigned long now, next, next_sec, next_sched;
  	struct inet6_ifaddr *ifp;
  	int i;
  
  	ASSERT_RTNL();
  
  	rcu_read_lock_bh();
  	now = jiffies;
  	next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);
  
  	cancel_delayed_work(&addr_chk_work);
  
  	for (i = 0; i < IN6_ADDR_HSIZE; i++) {
  restart:
  		hlist_for_each_entry_rcu_bh(ifp, &inet6_addr_lst[i], addr_lst) {
  			unsigned long age;
  
  			/* When setting preferred_lft to a value not zero or
  			 * infinity, while valid_lft is infinity
  			 * IFA_F_PERMANENT has a non-infinity life time.
  			 */
  			if ((ifp->flags & IFA_F_PERMANENT) &&
  			    (ifp->prefered_lft == INFINITY_LIFE_TIME))
  				continue;
  
  			spin_lock(&ifp->lock);
  			/* We try to batch several events at once. */
  			age = (now - ifp->tstamp + ADDRCONF_TIMER_FUZZ_MINUS) / HZ;
  
  			if (ifp->valid_lft != INFINITY_LIFE_TIME &&
  			    age >= ifp->valid_lft) {
  				spin_unlock(&ifp->lock);
  				in6_ifa_hold(ifp);
  				ipv6_del_addr(ifp);
  				goto restart;
  			} else if (ifp->prefered_lft == INFINITY_LIFE_TIME) {
  				spin_unlock(&ifp->lock);
  				continue;
  			} else if (age >= ifp->prefered_lft) {
  				/* jiffies - ifp->tstamp > age >= ifp->prefered_lft */
  				int deprecate = 0;
  
  				if (!(ifp->flags&IFA_F_DEPRECATED)) {
  					deprecate = 1;
  					ifp->flags |= IFA_F_DEPRECATED;
  				}
  
  				if ((ifp->valid_lft != INFINITY_LIFE_TIME) &&
  				    (time_before(ifp->tstamp + ifp->valid_lft * HZ, next)))
  					next = ifp->tstamp + ifp->valid_lft * HZ;
  
  				spin_unlock(&ifp->lock);
  
  				if (deprecate) {
  					in6_ifa_hold(ifp);
  
  					ipv6_ifa_notify(0, ifp);
  					in6_ifa_put(ifp);
  					goto restart;
  				}
  			} else if ((ifp->flags&IFA_F_TEMPORARY) &&
  				   !(ifp->flags&IFA_F_TENTATIVE)) {
  				unsigned long regen_advance = ifp->idev->cnf.regen_max_retry *
  					ifp->idev->cnf.dad_transmits *
  					NEIGH_VAR(ifp->idev->nd_parms, RETRANS_TIME) / HZ;
  
  				if (age >= ifp->prefered_lft - regen_advance) {
  					struct inet6_ifaddr *ifpub = ifp->ifpub;
  					if (time_before(ifp->tstamp + ifp->prefered_lft * HZ, next))
  						next = ifp->tstamp + ifp->prefered_lft * HZ;
  					if (!ifp->regen_count && ifpub) {
  						ifp->regen_count++;
  						in6_ifa_hold(ifp);
  						in6_ifa_hold(ifpub);
  						spin_unlock(&ifp->lock);
  
  						spin_lock(&ifpub->lock);
  						ifpub->regen_count = 0;
  						spin_unlock(&ifpub->lock);
  						ipv6_create_tempaddr(ifpub, ifp);
  						in6_ifa_put(ifpub);
  						in6_ifa_put(ifp);
  						goto restart;
  					}
  				} else if (time_before(ifp->tstamp + ifp->prefered_lft * HZ - regen_advance * HZ, next))
  					next = ifp->tstamp + ifp->prefered_lft * HZ - regen_advance * HZ;
  				spin_unlock(&ifp->lock);
  			} else {
  				/* ifp->prefered_lft <= ifp->valid_lft */
  				if (time_before(ifp->tstamp + ifp->prefered_lft * HZ, next))
  					next = ifp->tstamp + ifp->prefered_lft * HZ;
  				spin_unlock(&ifp->lock);
  			}
  		}
  	}
  
  	next_sec = round_jiffies_up(next);
  	next_sched = next;
  
  	/* If rounded timeout is accurate enough, accept it. */
  	if (time_before(next_sec, next + ADDRCONF_TIMER_FUZZ))
  		next_sched = next_sec;
  
  	/* And minimum interval is ADDRCONF_TIMER_FUZZ_MAX. */
  	if (time_before(next_sched, jiffies + ADDRCONF_TIMER_FUZZ_MAX))
  		next_sched = jiffies + ADDRCONF_TIMER_FUZZ_MAX;
  
  	ADBG(KERN_DEBUG "now = %lu, schedule = %lu, rounded schedule = %lu => %lu\n",
  	      now, next, next_sec, next_sched);
  	mod_delayed_work(addrconf_wq, &addr_chk_work, next_sched - now);
  	rcu_read_unlock_bh();
  }
  
  static void addrconf_verify_work(struct work_struct *w)
  {
  	rtnl_lock();
  	addrconf_verify_rtnl();
  	rtnl_unlock();
  }
  
  static void addrconf_verify(void)
  {
  	mod_delayed_work(addrconf_wq, &addr_chk_work, 0);
  }
  
  static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local,
  				     struct in6_addr **peer_pfx)
  {
  	struct in6_addr *pfx = NULL;
  
  	*peer_pfx = NULL;
  
  	if (addr)
  		pfx = nla_data(addr);
  
  	if (local) {
  		if (pfx && nla_memcmp(local, pfx, sizeof(*pfx)))
  			*peer_pfx = pfx;
  		pfx = nla_data(local);
  	}
  
  	return pfx;
  }
  
  static const struct nla_policy ifa_ipv6_policy[IFA_MAX+1] = {
  	[IFA_ADDRESS]		= { .len = sizeof(struct in6_addr) },
  	[IFA_LOCAL]		= { .len = sizeof(struct in6_addr) },
  	[IFA_CACHEINFO]		= { .len = sizeof(struct ifa_cacheinfo) },
  	[IFA_FLAGS]		= { .len = sizeof(u32) },
  };
  
  static int
  inet6_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
  		  struct netlink_ext_ack *extack)
  {
  	struct net *net = sock_net(skb->sk);
  	struct ifaddrmsg *ifm;
  	struct nlattr *tb[IFA_MAX+1];
  	struct in6_addr *pfx, *peer_pfx;
  	u32 ifa_flags;
  	int err;
  
  	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv6_policy,
  			  extack);
  	if (err < 0)
  		return err;
  
  	ifm = nlmsg_data(nlh);
  	pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer_pfx);
  	if (!pfx)
  		return -EINVAL;
  
  	ifa_flags = tb[IFA_FLAGS] ? nla_get_u32(tb[IFA_FLAGS]) : ifm->ifa_flags;
  
  	/* We ignore other flags so far. */
  	ifa_flags &= IFA_F_MANAGETEMPADDR;
  
  	return inet6_addr_del(net, ifm->ifa_index, ifa_flags, pfx,
  			      ifm->ifa_prefixlen);
  }
  
  static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags,
  			     u32 prefered_lft, u32 valid_lft)
  {
  	u32 flags;
  	clock_t expires;
  	unsigned long timeout;
  	bool was_managetempaddr;
  	bool had_prefixroute;
  
  	ASSERT_RTNL();
  
  	if (!valid_lft || (prefered_lft > valid_lft))
  		return -EINVAL;
  
  	if (ifa_flags & IFA_F_MANAGETEMPADDR &&
  	    (ifp->flags & IFA_F_TEMPORARY || ifp->prefix_len != 64))
  		return -EINVAL;
  
  	timeout = addrconf_timeout_fixup(valid_lft, HZ);
  	if (addrconf_finite_timeout(timeout)) {
  		expires = jiffies_to_clock_t(timeout * HZ);
  		valid_lft = timeout;
  		flags = RTF_EXPIRES;
  	} else {
  		expires = 0;
  		flags = 0;
  		ifa_flags |= IFA_F_PERMANENT;
  	}
  
  	timeout = addrconf_timeout_fixup(prefered_lft, HZ);
  	if (addrconf_finite_timeout(timeout)) {
  		if (timeout == 0)
  			ifa_flags |= IFA_F_DEPRECATED;
  		prefered_lft = timeout;
  	}
  
  	spin_lock_bh(&ifp->lock);
  	was_managetempaddr = ifp->flags & IFA_F_MANAGETEMPADDR;
  	had_prefixroute = ifp->flags & IFA_F_PERMANENT &&
  			  !(ifp->flags & IFA_F_NOPREFIXROUTE);
  	ifp->flags &= ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD |
  			IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR |
  			IFA_F_NOPREFIXROUTE);
  	ifp->flags |= ifa_flags;
  	ifp->tstamp = jiffies;
  	ifp->valid_lft = valid_lft;
  	ifp->prefered_lft = prefered_lft;
  
  	spin_unlock_bh(&ifp->lock);
  	if (!(ifp->flags&IFA_F_TENTATIVE))
  		ipv6_ifa_notify(0, ifp);
  
  	if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) {
  		addrconf_prefix_route(&ifp->addr, ifp->prefix_len, ifp->idev->dev,
  				      expires, flags);
  	} else if (had_prefixroute) {
  		enum cleanup_prefix_rt_t action;
  		unsigned long rt_expires;
  
  		write_lock_bh(&ifp->idev->lock);
  		action = check_cleanup_prefix_route(ifp, &rt_expires);
  		write_unlock_bh(&ifp->idev->lock);
  
  		if (action != CLEANUP_PREFIX_RT_NOP) {
  			cleanup_prefix_route(ifp, rt_expires,
  				action == CLEANUP_PREFIX_RT_DEL);
  		}
  	}
  
  	if (was_managetempaddr || ifp->flags & IFA_F_MANAGETEMPADDR) {
  		if (was_managetempaddr && !(ifp->flags & IFA_F_MANAGETEMPADDR))
  			valid_lft = prefered_lft = 0;
  		manage_tempaddrs(ifp->idev, ifp, valid_lft, prefered_lft,
  				 !was_managetempaddr, jiffies);
  	}
  
  	addrconf_verify_rtnl();
  
  	return 0;
  }
  
  static int
  inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
  		  struct netlink_ext_ack *extack)
  {
  	struct net *net = sock_net(skb->sk);
  	struct ifaddrmsg *ifm;
  	struct nlattr *tb[IFA_MAX+1];
  	struct in6_addr *pfx, *peer_pfx;
  	struct inet6_ifaddr *ifa;
  	struct net_device *dev;
  	u32 valid_lft = INFINITY_LIFE_TIME, preferred_lft = INFINITY_LIFE_TIME;
  	u32 ifa_flags;
  	int err;
  
  	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv6_policy,
  			  extack);
  	if (err < 0)
  		return err;
  
  	ifm = nlmsg_data(nlh);
  	pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer_pfx);
  	if (!pfx)
  		return -EINVAL;
  
  	if (tb[IFA_CACHEINFO]) {
  		struct ifa_cacheinfo *ci;
  
  		ci = nla_data(tb[IFA_CACHEINFO]);
  		valid_lft = ci->ifa_valid;
  		preferred_lft = ci->ifa_prefered;
  	} else {
  		preferred_lft = INFINITY_LIFE_TIME;
  		valid_lft = INFINITY_LIFE_TIME;
  	}
  
  	dev =  __dev_get_by_index(net, ifm->ifa_index);
  	if (!dev)
  		return -ENODEV;
  
  	ifa_flags = tb[IFA_FLAGS] ? nla_get_u32(tb[IFA_FLAGS]) : ifm->ifa_flags;
  
  	/* We ignore other flags so far. */
  	ifa_flags &= IFA_F_NODAD | IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR |
  		     IFA_F_NOPREFIXROUTE | IFA_F_MCAUTOJOIN;
  
  	ifa = ipv6_get_ifaddr(net, pfx, dev, 1);
  	if (!ifa) {
  		/*
  		 * It would be best to check for !NLM_F_CREATE here but
  		 * userspace already relies on not having to provide this.
  		 */
  		return inet6_addr_add(net, ifm->ifa_index, pfx, peer_pfx,
  				      ifm->ifa_prefixlen, ifa_flags,
  				      preferred_lft, valid_lft);
  	}
  
  	if (nlh->nlmsg_flags & NLM_F_EXCL ||
  	    !(nlh->nlmsg_flags & NLM_F_REPLACE))
  		err = -EEXIST;
  	else
  		err = inet6_addr_modify(ifa, ifa_flags, preferred_lft, valid_lft);
  
  	in6_ifa_put(ifa);
  
  	return err;
  }
  
  static void put_ifaddrmsg(struct nlmsghdr *nlh, u8 prefixlen, u32 flags,
  			  u8 scope, int ifindex)
  {
  	struct ifaddrmsg *ifm;
  
  	ifm = nlmsg_data(nlh);
  	ifm->ifa_family = AF_INET6;
  	ifm->ifa_prefixlen = prefixlen;
  	ifm->ifa_flags = flags;
  	ifm->ifa_scope = scope;
  	ifm->ifa_index = ifindex;
  }
  
  static int put_cacheinfo(struct sk_buff *skb, unsigned long cstamp,
  			 unsigned long tstamp, u32 preferred, u32 valid)
  {
  	struct ifa_cacheinfo ci;
  
  	ci.cstamp = cstamp_delta(cstamp);
  	ci.tstamp = cstamp_delta(tstamp);
  	ci.ifa_prefered = preferred;
  	ci.ifa_valid = valid;
  
  	return nla_put(skb, IFA_CACHEINFO, sizeof(ci), &ci);
  }
  
  static inline int rt_scope(int ifa_scope)
  {
  	if (ifa_scope & IFA_HOST)
  		return RT_SCOPE_HOST;
  	else if (ifa_scope & IFA_LINK)
  		return RT_SCOPE_LINK;
  	else if (ifa_scope & IFA_SITE)
  		return RT_SCOPE_SITE;
  	else
  		return RT_SCOPE_UNIVERSE;
  }
  
  static inline int inet6_ifaddr_msgsize(void)
  {
  	return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
  	       + nla_total_size(16) /* IFA_LOCAL */
  	       + nla_total_size(16) /* IFA_ADDRESS */
  	       + nla_total_size(sizeof(struct ifa_cacheinfo))
  	       + nla_total_size(4)  /* IFA_FLAGS */;
  }
  
  static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa,
  			     u32 portid, u32 seq, int event, unsigned int flags)
  {
  	struct nlmsghdr  *nlh;
  	u32 preferred, valid;
  
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct ifaddrmsg), flags);
  	if (!nlh)
  		return -EMSGSIZE;
  
  	put_ifaddrmsg(nlh, ifa->prefix_len, ifa->flags, rt_scope(ifa->scope),
  		      ifa->idev->dev->ifindex);
  
  	if (!((ifa->flags&IFA_F_PERMANENT) &&
  	      (ifa->prefered_lft == INFINITY_LIFE_TIME))) {
  		preferred = ifa->prefered_lft;
  		valid = ifa->valid_lft;
  		if (preferred != INFINITY_LIFE_TIME) {
  			long tval = (jiffies - ifa->tstamp)/HZ;
  			if (preferred > tval)
  				preferred -= tval;
  			else
  				preferred = 0;
  			if (valid != INFINITY_LIFE_TIME) {
  				if (valid > tval)
  					valid -= tval;
  				else
  					valid = 0;
  			}
  		}
  	} else {
  		preferred = INFINITY_LIFE_TIME;
  		valid = INFINITY_LIFE_TIME;
  	}
  
  	if (!ipv6_addr_any(&ifa->peer_addr)) {
  		if (nla_put_in6_addr(skb, IFA_LOCAL, &ifa->addr) < 0 ||
  		    nla_put_in6_addr(skb, IFA_ADDRESS, &ifa->peer_addr) < 0)
  			goto error;
  	} else
  		if (nla_put_in6_addr(skb, IFA_ADDRESS, &ifa->addr) < 0)
  			goto error;
  
  	if (put_cacheinfo(skb, ifa->cstamp, ifa->tstamp, preferred, valid) < 0)
  		goto error;
  
  	if (nla_put_u32(skb, IFA_FLAGS, ifa->flags) < 0)
  		goto error;
  
  	nlmsg_end(skb, nlh);
  	return 0;
  
  error:
  	nlmsg_cancel(skb, nlh);
  	return -EMSGSIZE;
  }
  
  static int inet6_fill_ifmcaddr(struct sk_buff *skb, struct ifmcaddr6 *ifmca,
  				u32 portid, u32 seq, int event, u16 flags)
  {
  	struct nlmsghdr  *nlh;
  	u8 scope = RT_SCOPE_UNIVERSE;
  	int ifindex = ifmca->idev->dev->ifindex;
  
  	if (ipv6_addr_scope(&ifmca->mca_addr) & IFA_SITE)
  		scope = RT_SCOPE_SITE;
  
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct ifaddrmsg), flags);
  	if (!nlh)
  		return -EMSGSIZE;
  
  	put_ifaddrmsg(nlh, 128, IFA_F_PERMANENT, scope, ifindex);
  	if (nla_put_in6_addr(skb, IFA_MULTICAST, &ifmca->mca_addr) < 0 ||
  	    put_cacheinfo(skb, ifmca->mca_cstamp, ifmca->mca_tstamp,
  			  INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0) {
  		nlmsg_cancel(skb, nlh);
  		return -EMSGSIZE;
  	}
  
  	nlmsg_end(skb, nlh);
  	return 0;
  }
  
  static int inet6_fill_ifacaddr(struct sk_buff *skb, struct ifacaddr6 *ifaca,
  				u32 portid, u32 seq, int event, unsigned int flags)
  {
  	struct nlmsghdr  *nlh;
  	u8 scope = RT_SCOPE_UNIVERSE;
  	int ifindex = ifaca->aca_idev->dev->ifindex;
  
  	if (ipv6_addr_scope(&ifaca->aca_addr) & IFA_SITE)
  		scope = RT_SCOPE_SITE;
  
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct ifaddrmsg), flags);
  	if (!nlh)
  		return -EMSGSIZE;
  
  	put_ifaddrmsg(nlh, 128, IFA_F_PERMANENT, scope, ifindex);
  	if (nla_put_in6_addr(skb, IFA_ANYCAST, &ifaca->aca_addr) < 0 ||
  	    put_cacheinfo(skb, ifaca->aca_cstamp, ifaca->aca_tstamp,
  			  INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0) {
  		nlmsg_cancel(skb, nlh);
  		return -EMSGSIZE;
  	}
  
  	nlmsg_end(skb, nlh);
  	return 0;
  }
  
  enum addr_type_t {
  	UNICAST_ADDR,
  	MULTICAST_ADDR,
  	ANYCAST_ADDR,
  };
  
  /* called with rcu_read_lock() */
  static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb,
  			  struct netlink_callback *cb, enum addr_type_t type,
  			  int s_ip_idx, int *p_ip_idx)
  {
  	struct ifmcaddr6 *ifmca;
  	struct ifacaddr6 *ifaca;
  	int err = 1;
  	int ip_idx = *p_ip_idx;
  
  	read_lock_bh(&idev->lock);
  	switch (type) {
  	case UNICAST_ADDR: {
  		struct inet6_ifaddr *ifa;
  
  		/* unicast address incl. temp addr */
  		list_for_each_entry(ifa, &idev->addr_list, if_list) {
  			if (ip_idx < s_ip_idx)
  				goto next;
  			err = inet6_fill_ifaddr(skb, ifa,
  						NETLINK_CB(cb->skb).portid,
  						cb->nlh->nlmsg_seq,
  						RTM_NEWADDR,
  						NLM_F_MULTI);
  			if (err < 0)
  				break;
  			nl_dump_check_consistent(cb, nlmsg_hdr(skb));
  next:
  			ip_idx++;
  		}
  		break;
  	}
  	case MULTICAST_ADDR:
  		/* multicast address */
  		for (ifmca = idev->mc_list; ifmca;
  		     ifmca = ifmca->next, ip_idx++) {
  			if (ip_idx < s_ip_idx)
  				continue;
  			err = inet6_fill_ifmcaddr(skb, ifmca,
  						  NETLINK_CB(cb->skb).portid,
  						  cb->nlh->nlmsg_seq,
  						  RTM_GETMULTICAST,
  						  NLM_F_MULTI);
  			if (err < 0)
  				break;
  		}
  		break;
  	case ANYCAST_ADDR:
  		/* anycast address */
  		for (ifaca = idev->ac_list; ifaca;
  		     ifaca = ifaca->aca_next, ip_idx++) {
  			if (ip_idx < s_ip_idx)
  				continue;
  			err = inet6_fill_ifacaddr(skb, ifaca,
  						  NETLINK_CB(cb->skb).portid,
  						  cb->nlh->nlmsg_seq,
  						  RTM_GETANYCAST,
  						  NLM_F_MULTI);
  			if (err < 0)
  				break;
  		}
  		break;
  	default:
  		break;
  	}
  	read_unlock_bh(&idev->lock);
  	*p_ip_idx = ip_idx;
  	return err;
  }
  
  static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
  			   enum addr_type_t type)
  {
  	struct net *net = sock_net(skb->sk);
  	int h, s_h;
  	int idx, ip_idx;
  	int s_idx, s_ip_idx;
  	struct net_device *dev;
  	struct inet6_dev *idev;
  	struct hlist_head *head;
  
  	s_h = cb->args[0];
  	s_idx = idx = cb->args[1];
  	s_ip_idx = ip_idx = cb->args[2];
  
  	rcu_read_lock();
  	cb->seq = atomic_read(&net->ipv6.dev_addr_genid) ^ net->dev_base_seq;
  	for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
  		idx = 0;
  		head = &net->dev_index_head[h];
  		hlist_for_each_entry_rcu(dev, head, index_hlist) {
  			if (idx < s_idx)
  				goto cont;
  			if (h > s_h || idx > s_idx)
  				s_ip_idx = 0;
  			ip_idx = 0;
  			idev = __in6_dev_get(dev);
  			if (!idev)
  				goto cont;
  
  			if (in6_dump_addrs(idev, skb, cb, type,
  					   s_ip_idx, &ip_idx) < 0)
  				goto done;
  cont:
  			idx++;
  		}
  	}
  done:
  	rcu_read_unlock();
  	cb->args[0] = h;
  	cb->args[1] = idx;
  	cb->args[2] = ip_idx;
  
  	return skb->len;
  }
  
  static int inet6_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	enum addr_type_t type = UNICAST_ADDR;
  
  	return inet6_dump_addr(skb, cb, type);
  }
  
  static int inet6_dump_ifmcaddr(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	enum addr_type_t type = MULTICAST_ADDR;
  
  	return inet6_dump_addr(skb, cb, type);
  }
  
  
  static int inet6_dump_ifacaddr(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	enum addr_type_t type = ANYCAST_ADDR;
  
  	return inet6_dump_addr(skb, cb, type);
  }
  
  static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr *nlh,
  			     struct netlink_ext_ack *extack)
  {
  	struct net *net = sock_net(in_skb->sk);
  	struct ifaddrmsg *ifm;
  	struct nlattr *tb[IFA_MAX+1];
  	struct in6_addr *addr = NULL, *peer;
  	struct net_device *dev = NULL;
  	struct inet6_ifaddr *ifa;
  	struct sk_buff *skb;
  	int err;
  
  	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv6_policy,
  			  extack);
  	if (err < 0)
  		goto errout;
  
  	addr = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer);
  	if (!addr) {
  		err = -EINVAL;
  		goto errout;
  	}
  
  	ifm = nlmsg_data(nlh);
  	if (ifm->ifa_index)
  		dev = __dev_get_by_index(net, ifm->ifa_index);
  
  	ifa = ipv6_get_ifaddr(net, addr, dev, 1);
  	if (!ifa) {
  		err = -EADDRNOTAVAIL;
  		goto errout;
  	}
  
  	skb = nlmsg_new(inet6_ifaddr_msgsize(), GFP_KERNEL);
  	if (!skb) {
  		err = -ENOBUFS;
  		goto errout_ifa;
  	}
  
  	err = inet6_fill_ifaddr(skb, ifa, NETLINK_CB(in_skb).portid,
  				nlh->nlmsg_seq, RTM_NEWADDR, 0);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet6_ifaddr_msgsize() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout_ifa;
  	}
  	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
  errout_ifa:
  	in6_ifa_put(ifa);
  errout:
  	return err;
  }
  
  static void inet6_ifa_notify(int event, struct inet6_ifaddr *ifa)
  {
  	struct sk_buff *skb;
  	struct net *net = dev_net(ifa->idev->dev);
  	int err = -ENOBUFS;
  
  	/* Don't send DELADDR notification for TENTATIVE address,
  	 * since NEWADDR notification is sent only after removing
  	 * TENTATIVE flag, if DAD has not failed.
  	 */
  	if (ifa->flags & IFA_F_TENTATIVE && !(ifa->flags & IFA_F_DADFAILED) &&
  	    event == RTM_DELADDR)
  		return;
  
  	skb = nlmsg_new(inet6_ifaddr_msgsize(), GFP_ATOMIC);
  	if (!skb)
  		goto errout;
  
  	err = inet6_fill_ifaddr(skb, ifa, 0, 0, event, 0);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet6_ifaddr_msgsize() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout;
  	}
  	rtnl_notify(skb, net, 0, RTNLGRP_IPV6_IFADDR, NULL, GFP_ATOMIC);
  	return;
  errout:
  	if (err < 0)
  		rtnl_set_sk_err(net, RTNLGRP_IPV6_IFADDR, err);
  }
  
  static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
  				__s32 *array, int bytes)
  {
  	BUG_ON(bytes < (DEVCONF_MAX * 4));
  
  	memset(array, 0, bytes);
  	array[DEVCONF_FORWARDING] = cnf->forwarding;
  	array[DEVCONF_HOPLIMIT] = cnf->hop_limit;
  	array[DEVCONF_MTU6] = cnf->mtu6;
  	array[DEVCONF_ACCEPT_RA] = cnf->accept_ra;
  	array[DEVCONF_ACCEPT_REDIRECTS] = cnf->accept_redirects;
  	array[DEVCONF_AUTOCONF] = cnf->autoconf;
  	array[DEVCONF_DAD_TRANSMITS] = cnf->dad_transmits;
  	array[DEVCONF_RTR_SOLICITS] = cnf->rtr_solicits;
  	array[DEVCONF_RTR_SOLICIT_INTERVAL] =
  		jiffies_to_msecs(cnf->rtr_solicit_interval);
  	array[DEVCONF_RTR_SOLICIT_MAX_INTERVAL] =
  		jiffies_to_msecs(cnf->rtr_solicit_max_interval);
  	array[DEVCONF_RTR_SOLICIT_DELAY] =
  		jiffies_to_msecs(cnf->rtr_solicit_delay);
  	array[DEVCONF_FORCE_MLD_VERSION] = cnf->force_mld_version;
  	array[DEVCONF_MLDV1_UNSOLICITED_REPORT_INTERVAL] =
  		jiffies_to_msecs(cnf->mldv1_unsolicited_report_interval);
  	array[DEVCONF_MLDV2_UNSOLICITED_REPORT_INTERVAL] =
  		jiffies_to_msecs(cnf->mldv2_unsolicited_report_interval);
  	array[DEVCONF_USE_TEMPADDR] = cnf->use_tempaddr;
  	array[DEVCONF_TEMP_VALID_LFT] = cnf->temp_valid_lft;
  	array[DEVCONF_TEMP_PREFERED_LFT] = cnf->temp_prefered_lft;
  	array[DEVCONF_REGEN_MAX_RETRY] = cnf->regen_max_retry;
  	array[DEVCONF_MAX_DESYNC_FACTOR] = cnf->max_desync_factor;
  	array[DEVCONF_MAX_ADDRESSES] = cnf->max_addresses;
  	array[DEVCONF_ACCEPT_RA_DEFRTR] = cnf->accept_ra_defrtr;
  	array[DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT] = cnf->accept_ra_min_hop_limit;
  	array[DEVCONF_ACCEPT_RA_PINFO] = cnf->accept_ra_pinfo;
  #ifdef CONFIG_IPV6_ROUTER_PREF
  	array[DEVCONF_ACCEPT_RA_RTR_PREF] = cnf->accept_ra_rtr_pref;
  	array[DEVCONF_RTR_PROBE_INTERVAL] =
  		jiffies_to_msecs(cnf->rtr_probe_interval);
  #ifdef CONFIG_IPV6_ROUTE_INFO
  	array[DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN] = cnf->accept_ra_rt_info_min_plen;
  	array[DEVCONF_ACCEPT_RA_RT_INFO_MAX_PLEN] = cnf->accept_ra_rt_info_max_plen;
  #endif
  #endif
  	array[DEVCONF_PROXY_NDP] = cnf->proxy_ndp;
  	array[DEVCONF_ACCEPT_SOURCE_ROUTE] = cnf->accept_source_route;
  #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
  	array[DEVCONF_OPTIMISTIC_DAD] = cnf->optimistic_dad;
  	array[DEVCONF_USE_OPTIMISTIC] = cnf->use_optimistic;
  #endif
  #ifdef CONFIG_IPV6_MROUTE
  	array[DEVCONF_MC_FORWARDING] = cnf->mc_forwarding;
  #endif
  	array[DEVCONF_DISABLE_IPV6] = cnf->disable_ipv6;
  	array[DEVCONF_ACCEPT_DAD] = cnf->accept_dad;
  	array[DEVCONF_FORCE_TLLAO] = cnf->force_tllao;
  	array[DEVCONF_NDISC_NOTIFY] = cnf->ndisc_notify;
  	array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc;
  	array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local;
  	array[DEVCONF_ACCEPT_RA_MTU] = cnf->accept_ra_mtu;
  	array[DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN] = cnf->ignore_routes_with_linkdown;
  	/* we omit DEVCONF_STABLE_SECRET for now */
  	array[DEVCONF_USE_OIF_ADDRS_ONLY] = cnf->use_oif_addrs_only;
  	array[DEVCONF_DROP_UNICAST_IN_L2_MULTICAST] = cnf->drop_unicast_in_l2_multicast;
  	array[DEVCONF_DROP_UNSOLICITED_NA] = cnf->drop_unsolicited_na;
  	array[DEVCONF_KEEP_ADDR_ON_DOWN] = cnf->keep_addr_on_down;
  	array[DEVCONF_SEG6_ENABLED] = cnf->seg6_enabled;
  #ifdef CONFIG_IPV6_SEG6_HMAC
  	array[DEVCONF_SEG6_REQUIRE_HMAC] = cnf->seg6_require_hmac;
  #endif
  	array[DEVCONF_ENHANCED_DAD] = cnf->enhanced_dad;
  	array[DEVCONF_ADDR_GEN_MODE] = cnf->addr_gen_mode;
  	array[DEVCONF_DISABLE_POLICY] = cnf->disable_policy;
  }
  
  static inline size_t inet6_ifla6_size(void)
  {
  	return nla_total_size(4) /* IFLA_INET6_FLAGS */
  	     + nla_total_size(sizeof(struct ifla_cacheinfo))
  	     + nla_total_size(DEVCONF_MAX * 4) /* IFLA_INET6_CONF */
  	     + nla_total_size(IPSTATS_MIB_MAX * 8) /* IFLA_INET6_STATS */
  	     + nla_total_size(ICMP6_MIB_MAX * 8) /* IFLA_INET6_ICMP6STATS */
  	     + nla_total_size(sizeof(struct in6_addr)); /* IFLA_INET6_TOKEN */
  }
  
  static inline size_t inet6_if_nlmsg_size(void)
  {
  	return NLMSG_ALIGN(sizeof(struct ifinfomsg))
  	       + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
  	       + nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
  	       + nla_total_size(4) /* IFLA_MTU */
  	       + nla_total_size(4) /* IFLA_LINK */
  	       + nla_total_size(1) /* IFLA_OPERSTATE */
  	       + nla_total_size(inet6_ifla6_size()); /* IFLA_PROTINFO */
  }
  
  static inline void __snmp6_fill_statsdev(u64 *stats, atomic_long_t *mib,
  					int bytes)
  {
  	int i;
  	int pad = bytes - sizeof(u64) * ICMP6_MIB_MAX;
  	BUG_ON(pad < 0);
  
  	/* Use put_unaligned() because stats may not be aligned for u64. */
  	put_unaligned(ICMP6_MIB_MAX, &stats[0]);
  	for (i = 1; i < ICMP6_MIB_MAX; i++)
  		put_unaligned(atomic_long_read(&mib[i]), &stats[i]);
  
  	memset(&stats[ICMP6_MIB_MAX], 0, pad);
  }
  
  static inline void __snmp6_fill_stats64(u64 *stats, void __percpu *mib,
  					int bytes, size_t syncpoff)
  {
  	int i, c;
  	u64 buff[IPSTATS_MIB_MAX];
  	int pad = bytes - sizeof(u64) * IPSTATS_MIB_MAX;
  
  	BUG_ON(pad < 0);
  
  	memset(buff, 0, sizeof(buff));
  	buff[0] = IPSTATS_MIB_MAX;
  
  	for_each_possible_cpu(c) {
  		for (i = 1; i < IPSTATS_MIB_MAX; i++)
  			buff[i] += snmp_get_cpu_field64(mib, c, i, syncpoff);
  	}
  
  	memcpy(stats, buff, IPSTATS_MIB_MAX * sizeof(u64));
  	memset(&stats[IPSTATS_MIB_MAX], 0, pad);
  }
  
  static void snmp6_fill_stats(u64 *stats, struct inet6_dev *idev, int attrtype,
  			     int bytes)
  {
  	switch (attrtype) {
  	case IFLA_INET6_STATS:
  		__snmp6_fill_stats64(stats, idev->stats.ipv6, bytes,
  				     offsetof(struct ipstats_mib, syncp));
  		break;
  	case IFLA_INET6_ICMP6STATS:
  		__snmp6_fill_statsdev(stats, idev->stats.icmpv6dev->mibs, bytes);
  		break;
  	}
  }
  
  static int inet6_fill_ifla6_attrs(struct sk_buff *skb, struct inet6_dev *idev,
  				  u32 ext_filter_mask)
  {
  	struct nlattr *nla;
  	struct ifla_cacheinfo ci;
  
  	if (nla_put_u32(skb, IFLA_INET6_FLAGS, idev->if_flags))
  		goto nla_put_failure;
  	ci.max_reasm_len = IPV6_MAXPLEN;
  	ci.tstamp = cstamp_delta(idev->tstamp);
  	ci.reachable_time = jiffies_to_msecs(idev->nd_parms->reachable_time);
  	ci.retrans_time = jiffies_to_msecs(NEIGH_VAR(idev->nd_parms, RETRANS_TIME));
  	if (nla_put(skb, IFLA_INET6_CACHEINFO, sizeof(ci), &ci))
  		goto nla_put_failure;
  	nla = nla_reserve(skb, IFLA_INET6_CONF, DEVCONF_MAX * sizeof(s32));
  	if (!nla)
  		goto nla_put_failure;
  	ipv6_store_devconf(&idev->cnf, nla_data(nla), nla_len(nla));
  
  	/* XXX - MC not implemented */
  
  	if (ext_filter_mask & RTEXT_FILTER_SKIP_STATS)
  		return 0;
  
  	nla = nla_reserve(skb, IFLA_INET6_STATS, IPSTATS_MIB_MAX * sizeof(u64));
  	if (!nla)
  		goto nla_put_failure;
  	snmp6_fill_stats(nla_data(nla), idev, IFLA_INET6_STATS, nla_len(nla));
  
  	nla = nla_reserve(skb, IFLA_INET6_ICMP6STATS, ICMP6_MIB_MAX * sizeof(u64));
  	if (!nla)
  		goto nla_put_failure;
  	snmp6_fill_stats(nla_data(nla), idev, IFLA_INET6_ICMP6STATS, nla_len(nla));
  
  	nla = nla_reserve(skb, IFLA_INET6_TOKEN, sizeof(struct in6_addr));
  	if (!nla)
  		goto nla_put_failure;
  
  	if (nla_put_u8(skb, IFLA_INET6_ADDR_GEN_MODE, idev->cnf.addr_gen_mode))
  		goto nla_put_failure;
  
  	read_lock_bh(&idev->lock);
  	memcpy(nla_data(nla), idev->token.s6_addr, nla_len(nla));
  	read_unlock_bh(&idev->lock);
  
  	return 0;
  
  nla_put_failure:
  	return -EMSGSIZE;
  }
  
  static size_t inet6_get_link_af_size(const struct net_device *dev,
  				     u32 ext_filter_mask)
  {
  	if (!__in6_dev_get(dev))
  		return 0;
  
  	return inet6_ifla6_size();
  }
  
  static int inet6_fill_link_af(struct sk_buff *skb, const struct net_device *dev,
  			      u32 ext_filter_mask)
  {
  	struct inet6_dev *idev = __in6_dev_get(dev);
  
  	if (!idev)
  		return -ENODATA;
  
  	if (inet6_fill_ifla6_attrs(skb, idev, ext_filter_mask) < 0)
  		return -EMSGSIZE;
  
  	return 0;
  }
  
  static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token)
  {
  	struct inet6_ifaddr *ifp;
  	struct net_device *dev = idev->dev;
  	bool clear_token, update_rs = false;
  	struct in6_addr ll_addr;
  
  	ASSERT_RTNL();
  
  	if (!token)
  		return -EINVAL;
  	if (dev->flags & (IFF_LOOPBACK | IFF_NOARP))
  		return -EINVAL;
  	if (!ipv6_accept_ra(idev))
  		return -EINVAL;
  	if (idev->cnf.rtr_solicits == 0)
  		return -EINVAL;
  
  	write_lock_bh(&idev->lock);
  
  	BUILD_BUG_ON(sizeof(token->s6_addr) != 16);
  	memcpy(idev->token.s6_addr + 8, token->s6_addr + 8, 8);
  
  	write_unlock_bh(&idev->lock);
  
  	clear_token = ipv6_addr_any(token);
  	if (clear_token)
  		goto update_lft;
  
  	if (!idev->dead && (idev->if_flags & IF_READY) &&
  	    !ipv6_get_lladdr(dev, &ll_addr, IFA_F_TENTATIVE |
  			     IFA_F_OPTIMISTIC)) {
  		/* If we're not ready, then normal ifup will take care
  		 * of this. Otherwise, we need to request our rs here.
  		 */
  		ndisc_send_rs(dev, &ll_addr, &in6addr_linklocal_allrouters);
  		update_rs = true;
  	}
  
  update_lft:
  	write_lock_bh(&idev->lock);
  
  	if (update_rs) {
  		idev->if_flags |= IF_RS_SENT;
  		idev->rs_interval = rfc3315_s14_backoff_init(
  			idev->cnf.rtr_solicit_interval);
  		idev->rs_probes = 1;
  		addrconf_mod_rs_timer(idev, idev->rs_interval);
  	}
  
  	/* Well, that's kinda nasty ... */
  	list_for_each_entry(ifp, &idev->addr_list, if_list) {
  		spin_lock(&ifp->lock);
  		if (ifp->tokenized) {
  			ifp->valid_lft = 0;
  			ifp->prefered_lft = 0;
  		}
  		spin_unlock(&ifp->lock);
  	}
  
  	write_unlock_bh(&idev->lock);
  	inet6_ifinfo_notify(RTM_NEWLINK, idev);
  	addrconf_verify_rtnl();
  	return 0;
  }
  
  static const struct nla_policy inet6_af_policy[IFLA_INET6_MAX + 1] = {
  	[IFLA_INET6_ADDR_GEN_MODE]	= { .type = NLA_U8 },
  	[IFLA_INET6_TOKEN]		= { .len = sizeof(struct in6_addr) },
  };
  
  static int inet6_validate_link_af(const struct net_device *dev,
  				  const struct nlattr *nla)
  {
  	struct nlattr *tb[IFLA_INET6_MAX + 1];
  
  	if (dev && !__in6_dev_get(dev))
  		return -EAFNOSUPPORT;
  
  	return nla_parse_nested(tb, IFLA_INET6_MAX, nla, inet6_af_policy,
  				NULL);
  }
  
  static int check_addr_gen_mode(int mode)
  {
  	if (mode != IN6_ADDR_GEN_MODE_EUI64 &&
  	    mode != IN6_ADDR_GEN_MODE_NONE &&
  	    mode != IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
  	    mode != IN6_ADDR_GEN_MODE_RANDOM)
  		return -EINVAL;
  	return 1;
  }
  
  static int check_stable_privacy(struct inet6_dev *idev, struct net *net,
  				int mode)
  {
  	if (mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
  	    !idev->cnf.stable_secret.initialized &&
  	    !net->ipv6.devconf_dflt->stable_secret.initialized)
  		return -EINVAL;
  	return 1;
  }
  
  static int inet6_set_link_af(struct net_device *dev, const struct nlattr *nla)
  {
  	int err = -EINVAL;
  	struct inet6_dev *idev = __in6_dev_get(dev);
  	struct nlattr *tb[IFLA_INET6_MAX + 1];
  
  	if (!idev)
  		return -EAFNOSUPPORT;
  
  	if (nla_parse_nested(tb, IFLA_INET6_MAX, nla, NULL, NULL) < 0)
  		BUG();
  
  	if (tb[IFLA_INET6_TOKEN]) {
  		err = inet6_set_iftoken(idev, nla_data(tb[IFLA_INET6_TOKEN]));
  		if (err)
  			return err;
  	}
  
  	if (tb[IFLA_INET6_ADDR_GEN_MODE]) {
  		u8 mode = nla_get_u8(tb[IFLA_INET6_ADDR_GEN_MODE]);
  
  		if (check_addr_gen_mode(mode) < 0 ||
  		    check_stable_privacy(idev, dev_net(dev), mode) < 0)
  			return -EINVAL;
  
  		idev->cnf.addr_gen_mode = mode;
  		err = 0;
  	}
  
  	return err;
  }
  
  static int inet6_fill_ifinfo(struct sk_buff *skb, struct inet6_dev *idev,
  			     u32 portid, u32 seq, int event, unsigned int flags)
  {
  	struct net_device *dev = idev->dev;
  	struct ifinfomsg *hdr;
  	struct nlmsghdr *nlh;
  	void *protoinfo;
  
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*hdr), flags);
  	if (!nlh)
  		return -EMSGSIZE;
  
  	hdr = nlmsg_data(nlh);
  	hdr->ifi_family = AF_INET6;
  	hdr->__ifi_pad = 0;
  	hdr->ifi_type = dev->type;
  	hdr->ifi_index = dev->ifindex;
  	hdr->ifi_flags = dev_get_flags(dev);
  	hdr->ifi_change = 0;
  
  	if (nla_put_string(skb, IFLA_IFNAME, dev->name) ||
  	    (dev->addr_len &&
  	     nla_put(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr)) ||
  	    nla_put_u32(skb, IFLA_MTU, dev->mtu) ||
  	    (dev->ifindex != dev_get_iflink(dev) &&
  	     nla_put_u32(skb, IFLA_LINK, dev_get_iflink(dev))) ||
  	    nla_put_u8(skb, IFLA_OPERSTATE,
  		       netif_running(dev) ? dev->operstate : IF_OPER_DOWN))
  		goto nla_put_failure;
  	protoinfo = nla_nest_start(skb, IFLA_PROTINFO);
  	if (!protoinfo)
  		goto nla_put_failure;
  
  	if (inet6_fill_ifla6_attrs(skb, idev, 0) < 0)
  		goto nla_put_failure;
  
  	nla_nest_end(skb, protoinfo);
  	nlmsg_end(skb, nlh);
  	return 0;
  
  nla_put_failure:
  	nlmsg_cancel(skb, nlh);
  	return -EMSGSIZE;
  }
  
  static int inet6_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	struct net *net = sock_net(skb->sk);
  	int h, s_h;
  	int idx = 0, s_idx;
  	struct net_device *dev;
  	struct inet6_dev *idev;
  	struct hlist_head *head;
  
  	s_h = cb->args[0];
  	s_idx = cb->args[1];
  
  	rcu_read_lock();
  	for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
  		idx = 0;
  		head = &net->dev_index_head[h];
  		hlist_for_each_entry_rcu(dev, head, index_hlist) {
  			if (idx < s_idx)
  				goto cont;
  			idev = __in6_dev_get(dev);
  			if (!idev)
  				goto cont;
  			if (inet6_fill_ifinfo(skb, idev,
  					      NETLINK_CB(cb->skb).portid,
  					      cb->nlh->nlmsg_seq,
  					      RTM_NEWLINK, NLM_F_MULTI) < 0)
  				goto out;
  cont:
  			idx++;
  		}
  	}
  out:
  	rcu_read_unlock();
  	cb->args[1] = idx;
  	cb->args[0] = h;
  
  	return skb->len;
  }
  
  void inet6_ifinfo_notify(int event, struct inet6_dev *idev)
  {
  	struct sk_buff *skb;
  	struct net *net = dev_net(idev->dev);
  	int err = -ENOBUFS;
  
  	skb = nlmsg_new(inet6_if_nlmsg_size(), GFP_ATOMIC);
  	if (!skb)
  		goto errout;
  
  	err = inet6_fill_ifinfo(skb, idev, 0, 0, event, 0);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet6_if_nlmsg_size() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout;
  	}
  	rtnl_notify(skb, net, 0, RTNLGRP_IPV6_IFINFO, NULL, GFP_ATOMIC);
  	return;
  errout:
  	if (err < 0)
  		rtnl_set_sk_err(net, RTNLGRP_IPV6_IFINFO, err);
  }
  
  static inline size_t inet6_prefix_nlmsg_size(void)
  {
  	return NLMSG_ALIGN(sizeof(struct prefixmsg))
  	       + nla_total_size(sizeof(struct in6_addr))
  	       + nla_total_size(sizeof(struct prefix_cacheinfo));
  }
  
  static int inet6_fill_prefix(struct sk_buff *skb, struct inet6_dev *idev,
  			     struct prefix_info *pinfo, u32 portid, u32 seq,
  			     int event, unsigned int flags)
  {
  	struct prefixmsg *pmsg;
  	struct nlmsghdr *nlh;
  	struct prefix_cacheinfo	ci;
  
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*pmsg), flags);
  	if (!nlh)
  		return -EMSGSIZE;
  
  	pmsg = nlmsg_data(nlh);
  	pmsg->prefix_family = AF_INET6;
  	pmsg->prefix_pad1 = 0;
  	pmsg->prefix_pad2 = 0;
  	pmsg->prefix_ifindex = idev->dev->ifindex;
  	pmsg->prefix_len = pinfo->prefix_len;
  	pmsg->prefix_type = pinfo->type;
  	pmsg->prefix_pad3 = 0;
  	pmsg->prefix_flags = 0;
  	if (pinfo->onlink)
  		pmsg->prefix_flags |= IF_PREFIX_ONLINK;
  	if (pinfo->autoconf)
  		pmsg->prefix_flags |= IF_PREFIX_AUTOCONF;
  
  	if (nla_put(skb, PREFIX_ADDRESS, sizeof(pinfo->prefix), &pinfo->prefix))
  		goto nla_put_failure;
  	ci.preferred_time = ntohl(pinfo->prefered);
  	ci.valid_time = ntohl(pinfo->valid);
  	if (nla_put(skb, PREFIX_CACHEINFO, sizeof(ci), &ci))
  		goto nla_put_failure;
  	nlmsg_end(skb, nlh);
  	return 0;
  
  nla_put_failure:
  	nlmsg_cancel(skb, nlh);
  	return -EMSGSIZE;
  }
  
  static void inet6_prefix_notify(int event, struct inet6_dev *idev,
  			 struct prefix_info *pinfo)
  {
  	struct sk_buff *skb;
  	struct net *net = dev_net(idev->dev);
  	int err = -ENOBUFS;
  
  	skb = nlmsg_new(inet6_prefix_nlmsg_size(), GFP_ATOMIC);
  	if (!skb)
  		goto errout;
  
  	err = inet6_fill_prefix(skb, idev, pinfo, 0, 0, event, 0);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet6_prefix_nlmsg_size() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout;
  	}
  	rtnl_notify(skb, net, 0, RTNLGRP_IPV6_PREFIX, NULL, GFP_ATOMIC);
  	return;
  errout:
  	if (err < 0)
  		rtnl_set_sk_err(net, RTNLGRP_IPV6_PREFIX, err);
  }
  
  static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
  {
  	struct net *net = dev_net(ifp->idev->dev);
  
  	if (event)
  		ASSERT_RTNL();
  
  	inet6_ifa_notify(event ? : RTM_NEWADDR, ifp);
  
  	switch (event) {
  	case RTM_NEWADDR:
  		/*
  		 * If the address was optimistic
  		 * we inserted the route at the start of
  		 * our DAD process, so we don't need
  		 * to do it again
  		 */
  		if (!rcu_access_pointer(ifp->rt->rt6i_node))
  			ip6_ins_rt(ifp->rt);
  		if (ifp->idev->cnf.forwarding)
  			addrconf_join_anycast(ifp);
  		if (!ipv6_addr_any(&ifp->peer_addr))
  			addrconf_prefix_route(&ifp->peer_addr, 128,
  					      ifp->idev->dev, 0, 0);
  		break;
  	case RTM_DELADDR:
  		if (ifp->idev->cnf.forwarding)
  			addrconf_leave_anycast(ifp);
  		addrconf_leave_solict(ifp->idev, &ifp->addr);
  		if (!ipv6_addr_any(&ifp->peer_addr)) {
  			struct rt6_info *rt;
  
  			rt = addrconf_get_prefix_route(&ifp->peer_addr, 128,
  						       ifp->idev->dev, 0, 0);
  			if (rt)
  				ip6_del_rt(rt);
  		}
  		if (ifp->rt) {
  			if (dst_hold_safe(&ifp->rt->dst))
  				ip6_del_rt(ifp->rt);
  		}
  		rt_genid_bump_ipv6(net);
  		break;
  	}
  	atomic_inc(&net->ipv6.dev_addr_genid);
  }
  
  static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
  {
  	rcu_read_lock_bh();
  	if (likely(ifp->idev->dead == 0))
  		__ipv6_ifa_notify(event, ifp);
  	rcu_read_unlock_bh();
  }
  
  #ifdef CONFIG_SYSCTL
  
  static
  int addrconf_sysctl_forward(struct ctl_table *ctl, int write,
  			   void __user *buffer, size_t *lenp, loff_t *ppos)
  {
  	int *valp = ctl->data;
  	int val = *valp;
  	loff_t pos = *ppos;
  	struct ctl_table lctl;
  	int ret;
  
  	/*
  	 * ctl->data points to idev->cnf.forwarding, we should
  	 * not modify it until we get the rtnl lock.
  	 */
  	lctl = *ctl;
  	lctl.data = &val;
  
  	ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);
  
  	if (write)
  		ret = addrconf_fixup_forwarding(ctl, valp, val);
  	if (ret)
  		*ppos = pos;
  	return ret;
  }
  
  static
  int addrconf_sysctl_mtu(struct ctl_table *ctl, int write,
  			void __user *buffer, size_t *lenp, loff_t *ppos)
  {
  	struct inet6_dev *idev = ctl->extra1;
  	int min_mtu = IPV6_MIN_MTU;
  	struct ctl_table lctl;
  
  	lctl = *ctl;
  	lctl.extra1 = &min_mtu;
  	lctl.extra2 = idev ? &idev->dev->mtu : NULL;
  
  	return proc_dointvec_minmax(&lctl, write, buffer, lenp, ppos);
  }
  
  static void dev_disable_change(struct inet6_dev *idev)
  {
  	struct netdev_notifier_info info;
  
  	if (!idev || !idev->dev)
  		return;
  
  	netdev_notifier_info_init(&info, idev->dev);
  	if (idev->cnf.disable_ipv6)
  		addrconf_notify(NULL, NETDEV_DOWN, &info);
  	else
  		addrconf_notify(NULL, NETDEV_UP, &info);
  }
  
  static void addrconf_disable_change(struct net *net, __s32 newf)
  {
  	struct net_device *dev;
  	struct inet6_dev *idev;
  
  	for_each_netdev(net, dev) {
  		idev = __in6_dev_get(dev);
  		if (idev) {
  			int changed = (!idev->cnf.disable_ipv6) ^ (!newf);
  			idev->cnf.disable_ipv6 = newf;
  			if (changed)
  				dev_disable_change(idev);
  		}
  	}
  }
  
  static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf)
  {
  	struct net *net;
  	int old;
  
  	if (!rtnl_trylock())
  		return restart_syscall();
  
  	net = (struct net *)table->extra2;
  	old = *p;
  	*p = newf;
  
  	if (p == &net->ipv6.devconf_dflt->disable_ipv6) {
  		rtnl_unlock();
  		return 0;
  	}
  
  	if (p == &net->ipv6.devconf_all->disable_ipv6) {
  		net->ipv6.devconf_dflt->disable_ipv6 = newf;
  		addrconf_disable_change(net, newf);
  	} else if ((!newf) ^ (!old))
  		dev_disable_change((struct inet6_dev *)table->extra1);
  
  	rtnl_unlock();
  	return 0;
  }
  
  static
  int addrconf_sysctl_disable(struct ctl_table *ctl, int write,
  			    void __user *buffer, size_t *lenp, loff_t *ppos)
  {
  	int *valp = ctl->data;
  	int val = *valp;
  	loff_t pos = *ppos;
  	struct ctl_table lctl;
  	int ret;
  
  	/*
  	 * ctl->data points to idev->cnf.disable_ipv6, we should
  	 * not modify it until we get the rtnl lock.
  	 */
  	lctl = *ctl;
  	lctl.data = &val;
  
  	ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);
  
  	if (write)
  		ret = addrconf_disable_ipv6(ctl, valp, val);
  	if (ret)
  		*ppos = pos;
  	return ret;
  }
  
  static
  int addrconf_sysctl_proxy_ndp(struct ctl_table *ctl, int write,
  			      void __user *buffer, size_t *lenp, loff_t *ppos)
  {
  	int *valp = ctl->data;
  	int ret;
  	int old, new;
  
  	old = *valp;
  	ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
  	new = *valp;
  
  	if (write && old != new) {
  		struct net *net = ctl->extra2;
  
  		if (!rtnl_trylock())
  			return restart_syscall();
  
  		if (valp == &net->ipv6.devconf_dflt->proxy_ndp)
  			inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
  						     NETCONFA_PROXY_NEIGH,
  						     NETCONFA_IFINDEX_DEFAULT,
  						     net->ipv6.devconf_dflt);
  		else if (valp == &net->ipv6.devconf_all->proxy_ndp)
  			inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
  						     NETCONFA_PROXY_NEIGH,
  						     NETCONFA_IFINDEX_ALL,
  						     net->ipv6.devconf_all);
  		else {
  			struct inet6_dev *idev = ctl->extra1;
  
  			inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
  						     NETCONFA_PROXY_NEIGH,
  						     idev->dev->ifindex,
  						     &idev->cnf);
  		}
  		rtnl_unlock();
  	}
  
  	return ret;
  }
  
  static int addrconf_sysctl_addr_gen_mode(struct ctl_table *ctl, int write,
  					 void __user *buffer, size_t *lenp,
  					 loff_t *ppos)
  {
  	int ret = 0;
  	int new_val;
  	struct inet6_dev *idev = (struct inet6_dev *)ctl->extra1;
  	struct net *net = (struct net *)ctl->extra2;
  
  	if (!rtnl_trylock())
  		return restart_syscall();
  
  	ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
  
  	if (write) {
  		new_val = *((int *)ctl->data);
  
  		if (check_addr_gen_mode(new_val) < 0) {
  			ret = -EINVAL;
  			goto out;
  		}
  
  		/* request for default */
  		if (&net->ipv6.devconf_dflt->addr_gen_mode == ctl->data) {
  			ipv6_devconf_dflt.addr_gen_mode = new_val;
  
  		/* request for individual net device */
  		} else {
  			if (!idev)
  				goto out;
  
  			if (check_stable_privacy(idev, net, new_val) < 0) {
  				ret = -EINVAL;
  				goto out;
  			}
  
  			if (idev->cnf.addr_gen_mode != new_val) {
  				idev->cnf.addr_gen_mode = new_val;
  				addrconf_dev_config(idev->dev);
  			}
  		}
  	}
  
  out:
  	rtnl_unlock();
  
  	return ret;
  }
  
  static int addrconf_sysctl_stable_secret(struct ctl_table *ctl, int write,
  					 void __user *buffer, size_t *lenp,
  					 loff_t *ppos)
  {
  	int err;
  	struct in6_addr addr;
  	char str[IPV6_MAX_STRLEN];
  	struct ctl_table lctl = *ctl;
  	struct net *net = ctl->extra2;
  	struct ipv6_stable_secret *secret = ctl->data;
  
  	if (&net->ipv6.devconf_all->stable_secret == ctl->data)
  		return -EIO;
  
  	lctl.maxlen = IPV6_MAX_STRLEN;
  	lctl.data = str;
  
  	if (!rtnl_trylock())
  		return restart_syscall();
  
  	if (!write && !secret->initialized) {
  		err = -EIO;
  		goto out;
  	}
  
  	err = snprintf(str, sizeof(str), "%pI6", &secret->secret);
  	if (err >= sizeof(str)) {
  		err = -EIO;
  		goto out;
  	}
  
  	err = proc_dostring(&lctl, write, buffer, lenp, ppos);
  	if (err || !write)
  		goto out;
  
  	if (in6_pton(str, -1, addr.in6_u.u6_addr8, -1, NULL) != 1) {
  		err = -EIO;
  		goto out;
  	}
  
  	secret->initialized = true;
  	secret->secret = addr;
  
  	if (&net->ipv6.devconf_dflt->stable_secret == ctl->data) {
  		struct net_device *dev;
  
  		for_each_netdev(net, dev) {
  			struct inet6_dev *idev = __in6_dev_get(dev);
  
  			if (idev) {
  				idev->cnf.addr_gen_mode =
  					IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
  			}
  		}
  	} else {
  		struct inet6_dev *idev = ctl->extra1;
  
  		idev->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
  	}
  
  out:
  	rtnl_unlock();
  
  	return err;
  }
  
  static
  int addrconf_sysctl_ignore_routes_with_linkdown(struct ctl_table *ctl,
  						int write,
  						void __user *buffer,
  						size_t *lenp,
  						loff_t *ppos)
  {
  	int *valp = ctl->data;
  	int val = *valp;
  	loff_t pos = *ppos;
  	struct ctl_table lctl;
  	int ret;
  
  	/* ctl->data points to idev->cnf.ignore_routes_when_linkdown
  	 * we should not modify it until we get the rtnl lock.
  	 */
  	lctl = *ctl;
  	lctl.data = &val;
  
  	ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);
  
  	if (write)
  		ret = addrconf_fixup_linkdown(ctl, valp, val);
  	if (ret)
  		*ppos = pos;
  	return ret;
  }
  
  static
  void addrconf_set_nopolicy(struct rt6_info *rt, int action)
  {
  	if (rt) {
  		if (action)
  			rt->dst.flags |= DST_NOPOLICY;
  		else
  			rt->dst.flags &= ~DST_NOPOLICY;
  	}
  }
  
  static
  void addrconf_disable_policy_idev(struct inet6_dev *idev, int val)
  {
  	struct inet6_ifaddr *ifa;
  
  	read_lock_bh(&idev->lock);
  	list_for_each_entry(ifa, &idev->addr_list, if_list) {
  		spin_lock(&ifa->lock);
  		if (ifa->rt) {
  			struct rt6_info *rt = ifa->rt;
  			struct fib6_table *table = rt->rt6i_table;
  			int cpu;
  
  			read_lock(&table->tb6_lock);
  			addrconf_set_nopolicy(ifa->rt, val);
  			if (rt->rt6i_pcpu) {
  				for_each_possible_cpu(cpu) {
  					struct rt6_info **rtp;
  
  					rtp = per_cpu_ptr(rt->rt6i_pcpu, cpu);
  					addrconf_set_nopolicy(*rtp, val);
  				}
  			}
  			read_unlock(&table->tb6_lock);
  		}
  		spin_unlock(&ifa->lock);
  	}
  	read_unlock_bh(&idev->lock);
  }
  
  static
  int addrconf_disable_policy(struct ctl_table *ctl, int *valp, int val)
  {
  	struct inet6_dev *idev;
  	struct net *net;
  
  	if (!rtnl_trylock())
  		return restart_syscall();
  
  	*valp = val;
  
  	net = (struct net *)ctl->extra2;
  	if (valp == &net->ipv6.devconf_dflt->disable_policy) {
  		rtnl_unlock();
  		return 0;
  	}
  
  	if (valp == &net->ipv6.devconf_all->disable_policy)  {
  		struct net_device *dev;
  
  		for_each_netdev(net, dev) {
  			idev = __in6_dev_get(dev);
  			if (idev)
  				addrconf_disable_policy_idev(idev, val);
  		}
  	} else {
  		idev = (struct inet6_dev *)ctl->extra1;
  		addrconf_disable_policy_idev(idev, val);
  	}
  
  	rtnl_unlock();
  	return 0;
  }
  
  static
  int addrconf_sysctl_disable_policy(struct ctl_table *ctl, int write,
  				   void __user *buffer, size_t *lenp,
  				   loff_t *ppos)
  {
  	int *valp = ctl->data;
  	int val = *valp;
  	loff_t pos = *ppos;
  	struct ctl_table lctl;
  	int ret;
  
  	lctl = *ctl;
  	lctl.data = &val;
  	ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);
  
  	if (write && (*valp != val))
  		ret = addrconf_disable_policy(ctl, valp, val);
  
  	if (ret)
  		*ppos = pos;
  
  	return ret;
  }
  
  static int minus_one = -1;
  static const int one = 1;
  static const int two_five_five = 255;
  
  static const struct ctl_table addrconf_sysctl[] = {
  	{
  		.procname	= "forwarding",
  		.data		= &ipv6_devconf.forwarding,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= addrconf_sysctl_forward,
  	},
  	{
  		.procname	= "hop_limit",
  		.data		= &ipv6_devconf.hop_limit,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= (void *)&one,
  		.extra2		= (void *)&two_five_five,
  	},
  	{
  		.procname	= "mtu",
  		.data		= &ipv6_devconf.mtu6,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= addrconf_sysctl_mtu,
  	},
  	{
  		.procname	= "accept_ra",
  		.data		= &ipv6_devconf.accept_ra,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "accept_redirects",
  		.data		= &ipv6_devconf.accept_redirects,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "autoconf",
  		.data		= &ipv6_devconf.autoconf,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "dad_transmits",
  		.data		= &ipv6_devconf.dad_transmits,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "router_solicitations",
  		.data		= &ipv6_devconf.rtr_solicits,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= &minus_one,
  	},
  	{
  		.procname	= "router_solicitation_interval",
  		.data		= &ipv6_devconf.rtr_solicit_interval,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  	{
  		.procname	= "router_solicitation_max_interval",
  		.data		= &ipv6_devconf.rtr_solicit_max_interval,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  	{
  		.procname	= "router_solicitation_delay",
  		.data		= &ipv6_devconf.rtr_solicit_delay,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  	{
  		.procname	= "force_mld_version",
  		.data		= &ipv6_devconf.force_mld_version,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "mldv1_unsolicited_report_interval",
  		.data		=
  			&ipv6_devconf.mldv1_unsolicited_report_interval,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_ms_jiffies,
  	},
  	{
  		.procname	= "mldv2_unsolicited_report_interval",
  		.data		=
  			&ipv6_devconf.mldv2_unsolicited_report_interval,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_ms_jiffies,
  	},
  	{
  		.procname	= "use_tempaddr",
  		.data		= &ipv6_devconf.use_tempaddr,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "temp_valid_lft",
  		.data		= &ipv6_devconf.temp_valid_lft,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "temp_prefered_lft",
  		.data		= &ipv6_devconf.temp_prefered_lft,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "regen_max_retry",
  		.data		= &ipv6_devconf.regen_max_retry,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "max_desync_factor",
  		.data		= &ipv6_devconf.max_desync_factor,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "max_addresses",
  		.data		= &ipv6_devconf.max_addresses,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "accept_ra_defrtr",
  		.data		= &ipv6_devconf.accept_ra_defrtr,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "accept_ra_min_hop_limit",
  		.data		= &ipv6_devconf.accept_ra_min_hop_limit,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "accept_ra_pinfo",
  		.data		= &ipv6_devconf.accept_ra_pinfo,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  #ifdef CONFIG_IPV6_ROUTER_PREF
  	{
  		.procname	= "accept_ra_rtr_pref",
  		.data		= &ipv6_devconf.accept_ra_rtr_pref,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "router_probe_interval",
  		.data		= &ipv6_devconf.rtr_probe_interval,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  #ifdef CONFIG_IPV6_ROUTE_INFO
  	{
  		.procname	= "accept_ra_rt_info_min_plen",
  		.data		= &ipv6_devconf.accept_ra_rt_info_min_plen,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "accept_ra_rt_info_max_plen",
  		.data		= &ipv6_devconf.accept_ra_rt_info_max_plen,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  #endif
  #endif
  	{
  		.procname	= "proxy_ndp",
  		.data		= &ipv6_devconf.proxy_ndp,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= addrconf_sysctl_proxy_ndp,
  	},
  	{
  		.procname	= "accept_source_route",
  		.data		= &ipv6_devconf.accept_source_route,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
  	{
  		.procname	= "optimistic_dad",
  		.data		= &ipv6_devconf.optimistic_dad,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler   = proc_dointvec,
  	},
  	{
  		.procname	= "use_optimistic",
  		.data		= &ipv6_devconf.use_optimistic,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  #endif
  #ifdef CONFIG_IPV6_MROUTE
  	{
  		.procname	= "mc_forwarding",
  		.data		= &ipv6_devconf.mc_forwarding,
  		.maxlen		= sizeof(int),
  		.mode		= 0444,
  		.proc_handler	= proc_dointvec,
  	},
  #endif
  	{
  		.procname	= "disable_ipv6",
  		.data		= &ipv6_devconf.disable_ipv6,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= addrconf_sysctl_disable,
  	},
  	{
  		.procname	= "accept_dad",
  		.data		= &ipv6_devconf.accept_dad,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "force_tllao",
  		.data		= &ipv6_devconf.force_tllao,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "ndisc_notify",
  		.data		= &ipv6_devconf.ndisc_notify,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "suppress_frag_ndisc",
  		.data		= &ipv6_devconf.suppress_frag_ndisc,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "accept_ra_from_local",
  		.data		= &ipv6_devconf.accept_ra_from_local,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "accept_ra_mtu",
  		.data		= &ipv6_devconf.accept_ra_mtu,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "stable_secret",
  		.data		= &ipv6_devconf.stable_secret,
  		.maxlen		= IPV6_MAX_STRLEN,
  		.mode		= 0600,
  		.proc_handler	= addrconf_sysctl_stable_secret,
  	},
  	{
  		.procname	= "use_oif_addrs_only",
  		.data		= &ipv6_devconf.use_oif_addrs_only,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "ignore_routes_with_linkdown",
  		.data		= &ipv6_devconf.ignore_routes_with_linkdown,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= addrconf_sysctl_ignore_routes_with_linkdown,
  	},
  	{
  		.procname	= "drop_unicast_in_l2_multicast",
  		.data		= &ipv6_devconf.drop_unicast_in_l2_multicast,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "drop_unsolicited_na",
  		.data		= &ipv6_devconf.drop_unsolicited_na,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "keep_addr_on_down",
  		.data		= &ipv6_devconf.keep_addr_on_down,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  
  	},
  	{
  		.procname	= "seg6_enabled",
  		.data		= &ipv6_devconf.seg6_enabled,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  #ifdef CONFIG_IPV6_SEG6_HMAC
  	{
  		.procname	= "seg6_require_hmac",
  		.data		= &ipv6_devconf.seg6_require_hmac,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  #endif
  	{
  		.procname       = "enhanced_dad",
  		.data           = &ipv6_devconf.enhanced_dad,
  		.maxlen         = sizeof(int),
  		.mode           = 0644,
  		.proc_handler   = proc_dointvec,
  	},
  	{
  		.procname		= "addr_gen_mode",
  		.data			= &ipv6_devconf.addr_gen_mode,
  		.maxlen			= sizeof(int),
  		.mode			= 0644,
  		.proc_handler	= addrconf_sysctl_addr_gen_mode,
  	},
  	{
  		.procname       = "disable_policy",
  		.data           = &ipv6_devconf.disable_policy,
  		.maxlen         = sizeof(int),
  		.mode           = 0644,
  		.proc_handler   = addrconf_sysctl_disable_policy,
  	},
  	{
  		/* sentinel */
  	}
  };
  
  static int __addrconf_sysctl_register(struct net *net, char *dev_name,
  		struct inet6_dev *idev, struct ipv6_devconf *p)
  {
  	int i, ifindex;
  	struct ctl_table *table;
  	char path[sizeof("net/ipv6/conf/") + IFNAMSIZ];
  
  	table = kmemdup(addrconf_sysctl, sizeof(addrconf_sysctl), GFP_KERNEL);
  	if (!table)
  		goto out;
  
  	for (i = 0; table[i].data; i++) {
  		table[i].data += (char *)p - (char *)&ipv6_devconf;
  		/* If one of these is already set, then it is not safe to
  		 * overwrite either of them: this makes proc_dointvec_minmax
  		 * usable.
  		 */
  		if (!table[i].extra1 && !table[i].extra2) {
  			table[i].extra1 = idev; /* embedded; no ref */
  			table[i].extra2 = net;
  		}
  	}
  
  	snprintf(path, sizeof(path), "net/ipv6/conf/%s", dev_name);
  
  	p->sysctl_header = register_net_sysctl(net, path, table);
  	if (!p->sysctl_header)
  		goto free;
  
  	if (!strcmp(dev_name, "all"))
  		ifindex = NETCONFA_IFINDEX_ALL;
  	else if (!strcmp(dev_name, "default"))
  		ifindex = NETCONFA_IFINDEX_DEFAULT;
  	else
  		ifindex = idev->dev->ifindex;
  	inet6_netconf_notify_devconf(net, RTM_NEWNETCONF, NETCONFA_ALL,
  				     ifindex, p);
  	return 0;
  
  free:
  	kfree(table);
  out:
  	return -ENOBUFS;
  }
  
  static void __addrconf_sysctl_unregister(struct net *net,
  					 struct ipv6_devconf *p, int ifindex)
  {
  	struct ctl_table *table;
  
  	if (!p->sysctl_header)
  		return;
  
  	table = p->sysctl_header->ctl_table_arg;
  	unregister_net_sysctl_table(p->sysctl_header);
  	p->sysctl_header = NULL;
  	kfree(table);
  
  	inet6_netconf_notify_devconf(net, RTM_DELNETCONF, 0, ifindex, NULL);
  }
  
  static int addrconf_sysctl_register(struct inet6_dev *idev)
  {
  	int err;
  
  	if (!sysctl_dev_name_is_allowed(idev->dev->name))
  		return -EINVAL;
  
  	err = neigh_sysctl_register(idev->dev, idev->nd_parms,
  				    &ndisc_ifinfo_sysctl_change);
  	if (err)
  		return err;
  	err = __addrconf_sysctl_register(dev_net(idev->dev), idev->dev->name,
  					 idev, &idev->cnf);
  	if (err)
  		neigh_sysctl_unregister(idev->nd_parms);
  
  	return err;
  }
  
  static void addrconf_sysctl_unregister(struct inet6_dev *idev)
  {
  	__addrconf_sysctl_unregister(dev_net(idev->dev), &idev->cnf,
  				     idev->dev->ifindex);
  	neigh_sysctl_unregister(idev->nd_parms);
  }
  
  
  #endif
  
  static int __net_init addrconf_init_net(struct net *net)
  {
  	int err = -ENOMEM;
  	struct ipv6_devconf *all, *dflt;
  
  	all = kmemdup(&ipv6_devconf, sizeof(ipv6_devconf), GFP_KERNEL);
  	if (!all)
  		goto err_alloc_all;
  
  	dflt = kmemdup(&ipv6_devconf_dflt, sizeof(ipv6_devconf_dflt), GFP_KERNEL);
  	if (!dflt)
  		goto err_alloc_dflt;
  
  	/* these will be inherited by all namespaces */
  	dflt->autoconf = ipv6_defaults.autoconf;
  	dflt->disable_ipv6 = ipv6_defaults.disable_ipv6;
  
  	dflt->stable_secret.initialized = false;
  	all->stable_secret.initialized = false;
  
  	net->ipv6.devconf_all = all;
  	net->ipv6.devconf_dflt = dflt;
  
  #ifdef CONFIG_SYSCTL
  	err = __addrconf_sysctl_register(net, "all", NULL, all);
  	if (err < 0)
  		goto err_reg_all;
  
  	err = __addrconf_sysctl_register(net, "default", NULL, dflt);
  	if (err < 0)
  		goto err_reg_dflt;
  #endif
  	return 0;
  
  #ifdef CONFIG_SYSCTL
  err_reg_dflt:
  	__addrconf_sysctl_unregister(net, all, NETCONFA_IFINDEX_ALL);
  err_reg_all:
  	kfree(dflt);
  #endif
  err_alloc_dflt:
  	kfree(all);
  err_alloc_all:
  	return err;
  }
  
  static void __net_exit addrconf_exit_net(struct net *net)
  {
  #ifdef CONFIG_SYSCTL
  	__addrconf_sysctl_unregister(net, net->ipv6.devconf_dflt,
  				     NETCONFA_IFINDEX_DEFAULT);
  	__addrconf_sysctl_unregister(net, net->ipv6.devconf_all,
  				     NETCONFA_IFINDEX_ALL);
  #endif
  	kfree(net->ipv6.devconf_dflt);
  	kfree(net->ipv6.devconf_all);
  }
  
  static struct pernet_operations addrconf_ops = {
  	.init = addrconf_init_net,
  	.exit = addrconf_exit_net,
  };
  
  static struct rtnl_af_ops inet6_ops __read_mostly = {
  	.family		  = AF_INET6,
  	.fill_link_af	  = inet6_fill_link_af,
  	.get_link_af_size = inet6_get_link_af_size,
  	.validate_link_af = inet6_validate_link_af,
  	.set_link_af	  = inet6_set_link_af,
  };
  
  /*
   *	Init / cleanup code
   */
  
  int __init addrconf_init(void)
  {
  	struct inet6_dev *idev;
  	int i, err;
  
  	err = ipv6_addr_label_init();
  	if (err < 0) {
  		pr_crit("%s: cannot initialize default policy table: %d\n",
  			__func__, err);
  		goto out;
  	}
  
  	err = register_pernet_subsys(&addrconf_ops);
  	if (err < 0)
  		goto out_addrlabel;
  
  	addrconf_wq = create_workqueue("ipv6_addrconf");
  	if (!addrconf_wq) {
  		err = -ENOMEM;
  		goto out_nowq;
  	}
  
  	/* The addrconf netdev notifier requires that loopback_dev
  	 * has it's ipv6 private information allocated and setup
  	 * before it can bring up and give link-local addresses
  	 * to other devices which are up.
  	 *
  	 * Unfortunately, loopback_dev is not necessarily the first
  	 * entry in the global dev_base list of net devices.  In fact,
  	 * it is likely to be the very last entry on that list.
  	 * So this causes the notifier registry below to try and
  	 * give link-local addresses to all devices besides loopback_dev
  	 * first, then loopback_dev, which cases all the non-loopback_dev
  	 * devices to fail to get a link-local address.
  	 *
  	 * So, as a temporary fix, allocate the ipv6 structure for
  	 * loopback_dev first by hand.
  	 * Longer term, all of the dependencies ipv6 has upon the loopback
  	 * device and it being up should be removed.
  	 */
  	rtnl_lock();
  	idev = ipv6_add_dev(init_net.loopback_dev);
  	rtnl_unlock();
  	if (IS_ERR(idev)) {
  		err = PTR_ERR(idev);
  		goto errlo;
  	}
  
  	ip6_route_init_special_entries();
  
  	for (i = 0; i < IN6_ADDR_HSIZE; i++)
  		INIT_HLIST_HEAD(&inet6_addr_lst[i]);
  
  	register_netdevice_notifier(&ipv6_dev_notf);
  
  	addrconf_verify();
  
  	rtnl_af_register(&inet6_ops);
  
  	err = __rtnl_register(PF_INET6, RTM_GETLINK, NULL, inet6_dump_ifinfo,
  			      0);
  	if (err < 0)
  		goto errout;
  
  	/* Only the first call to __rtnl_register can fail */
  	__rtnl_register(PF_INET6, RTM_NEWADDR, inet6_rtm_newaddr, NULL, 0);
  	__rtnl_register(PF_INET6, RTM_DELADDR, inet6_rtm_deladdr, NULL, 0);
  	__rtnl_register(PF_INET6, RTM_GETADDR, inet6_rtm_getaddr,
  			inet6_dump_ifaddr, 0);
  	__rtnl_register(PF_INET6, RTM_GETMULTICAST, NULL,
  			inet6_dump_ifmcaddr, 0);
  	__rtnl_register(PF_INET6, RTM_GETANYCAST, NULL,
  			inet6_dump_ifacaddr, 0);
  	__rtnl_register(PF_INET6, RTM_GETNETCONF, inet6_netconf_get_devconf,
  			inet6_netconf_dump_devconf, 0);
  
  	ipv6_addr_label_rtnl_register();
  
  	return 0;
  errout:
  	rtnl_af_unregister(&inet6_ops);
  	unregister_netdevice_notifier(&ipv6_dev_notf);
  errlo:
  	destroy_workqueue(addrconf_wq);
  out_nowq:
  	unregister_pernet_subsys(&addrconf_ops);
  out_addrlabel:
  	ipv6_addr_label_cleanup();
  out:
  	return err;
  }
  
  void addrconf_cleanup(void)
  {
  	struct net_device *dev;
  	int i;
  
  	unregister_netdevice_notifier(&ipv6_dev_notf);
  	unregister_pernet_subsys(&addrconf_ops);
  	ipv6_addr_label_cleanup();
  
  	rtnl_lock();
  
  	__rtnl_af_unregister(&inet6_ops);
  
  	/* clean dev list */
  	for_each_netdev(&init_net, dev) {
  		if (__in6_dev_get(dev) == NULL)
  			continue;
  		addrconf_ifdown(dev, 1);
  	}
  	addrconf_ifdown(init_net.loopback_dev, 2);
  
  	/*
  	 *	Check hash table.
  	 */
  	spin_lock_bh(&addrconf_hash_lock);
  	for (i = 0; i < IN6_ADDR_HSIZE; i++)
  		WARN_ON(!hlist_empty(&inet6_addr_lst[i]));
  	spin_unlock_bh(&addrconf_hash_lock);
  	cancel_delayed_work(&addr_chk_work);
  	rtnl_unlock();
  
  	destroy_workqueue(addrconf_wq);
  }
  