text: /*
   *	NET3	IP device support routines.
   *
   *		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.
   *
   *	Derived from the IP parts of dev.c 1.0.19
   * 		Authors:	Ross Biro
   *				Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
   *				Mark Evans, <evansmp@uhura.aston.ac.uk>
   *
   *	Additional Authors:
   *		Alan Cox, <gw4pts@gw4pts.ampr.org>
   *		Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   *
   *	Changes:
   *		Alexey Kuznetsov:	pa_* fields are replaced with ifaddr
   *					lists.
   *		Cyrus Durgin:		updated for kmod
   *		Matthias Andree:	in devinet_ioctl, compare label and
   *					address (4.4BSD alias style support),
   *					fall back to comparing just the label
   *					if no match found.
   */
  
  
  #include <asm/uaccess.h>
  #include <linux/bitops.h>
  #include <linux/capability.h>
  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/string.h>
  #include <linux/mm.h>
  #include <linux/socket.h>
  #include <linux/sockios.h>
  #include <linux/in.h>
  #include <linux/errno.h>
  #include <linux/interrupt.h>
  #include <linux/if_addr.h>
  #include <linux/if_ether.h>
  #include <linux/inet.h>
  #include <linux/netdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/skbuff.h>
  #include <linux/init.h>
  #include <linux/notifier.h>
  #include <linux/inetdevice.h>
  #include <linux/igmp.h>
  #include <linux/slab.h>
  #include <linux/hash.h>
  #ifdef CONFIG_SYSCTL
  #include <linux/sysctl.h>
  #endif
  #include <linux/kmod.h>
  #include <linux/netconf.h>
  
  #include <net/arp.h>
  #include <net/ip.h>
  #include <net/route.h>
  #include <net/ip_fib.h>
  #include <net/rtnetlink.h>
  #include <net/net_namespace.h>
  #include <net/addrconf.h>
  
  #include "fib_lookup.h"
  
  static struct ipv4_devconf ipv4_devconf = {
  	.data = {
  		[IPV4_DEVCONF_ACCEPT_REDIRECTS - 1] = 1,
  		[IPV4_DEVCONF_SEND_REDIRECTS - 1] = 1,
  		[IPV4_DEVCONF_SECURE_REDIRECTS - 1] = 1,
  		[IPV4_DEVCONF_SHARED_MEDIA - 1] = 1,
  		[IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL - 1] = 10000 /*ms*/,
  		[IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL - 1] =  1000 /*ms*/,
  	},
  };
  
  static struct ipv4_devconf ipv4_devconf_dflt = {
  	.data = {
  		[IPV4_DEVCONF_ACCEPT_REDIRECTS - 1] = 1,
  		[IPV4_DEVCONF_SEND_REDIRECTS - 1] = 1,
  		[IPV4_DEVCONF_SECURE_REDIRECTS - 1] = 1,
  		[IPV4_DEVCONF_SHARED_MEDIA - 1] = 1,
  		[IPV4_DEVCONF_ACCEPT_SOURCE_ROUTE - 1] = 1,
  		[IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL - 1] = 10000 /*ms*/,
  		[IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL - 1] =  1000 /*ms*/,
  	},
  };
  
  #define IPV4_DEVCONF_DFLT(net, attr) \
  	IPV4_DEVCONF((*net->ipv4.devconf_dflt), attr)
  
  static const struct nla_policy ifa_ipv4_policy[IFA_MAX+1] = {
  	[IFA_LOCAL]     	= { .type = NLA_U32 },
  	[IFA_ADDRESS]   	= { .type = NLA_U32 },
  	[IFA_BROADCAST] 	= { .type = NLA_U32 },
  	[IFA_LABEL]     	= { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
  	[IFA_CACHEINFO]		= { .len = sizeof(struct ifa_cacheinfo) },
  	[IFA_FLAGS]		= { .type = NLA_U32 },
  };
  
  #define IN4_ADDR_HSIZE_SHIFT	8
  #define IN4_ADDR_HSIZE		(1U << IN4_ADDR_HSIZE_SHIFT)
  
  static struct hlist_head inet_addr_lst[IN4_ADDR_HSIZE];
  
  static u32 inet_addr_hash(const struct net *net, __be32 addr)
  {
  	u32 val = (__force u32) addr ^ net_hash_mix(net);
  
  	return hash_32(val, IN4_ADDR_HSIZE_SHIFT);
  }
  
  static void inet_hash_insert(struct net *net, struct in_ifaddr *ifa)
  {
  	u32 hash = inet_addr_hash(net, ifa->ifa_local);
  
  	ASSERT_RTNL();
  	hlist_add_head_rcu(&ifa->hash, &inet_addr_lst[hash]);
  }
  
  static void inet_hash_remove(struct in_ifaddr *ifa)
  {
  	ASSERT_RTNL();
  	hlist_del_init_rcu(&ifa->hash);
  }
  
  /**
   * __ip_dev_find - find the first device with a given source address.
   * @net: the net namespace
   * @addr: the source address
   * @devref: if true, take a reference on the found device
   *
   * If a caller uses devref=false, it should be protected by RCU, or RTNL
   */
  struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
  {
  	u32 hash = inet_addr_hash(net, addr);
  	struct net_device *result = NULL;
  	struct in_ifaddr *ifa;
  
  	rcu_read_lock();
  	hlist_for_each_entry_rcu(ifa, &inet_addr_lst[hash], hash) {
  		if (ifa->ifa_local == addr) {
  			struct net_device *dev = ifa->ifa_dev->dev;
  
  			if (!net_eq(dev_net(dev), net))
  				continue;
  			result = dev;
  			break;
  		}
  	}
  	if (!result) {
  		struct flowi4 fl4 = { .daddr = addr };
  		struct fib_result res = { 0 };
  		struct fib_table *local;
  
  		/* Fallback to FIB local table so that communication
  		 * over loopback subnets work.
  		 */
  		local = fib_get_table(net, RT_TABLE_LOCAL);
  		if (local &&
  		    !fib_table_lookup(local, &fl4, &res, FIB_LOOKUP_NOREF) &&
  		    res.type == RTN_LOCAL)
  			result = FIB_RES_DEV(res);
  	}
  	if (result && devref)
  		dev_hold(result);
  	rcu_read_unlock();
  	return result;
  }
  EXPORT_SYMBOL(__ip_dev_find);
  
  static void rtmsg_ifa(int event, struct in_ifaddr *, struct nlmsghdr *, u32);
  
  static BLOCKING_NOTIFIER_HEAD(inetaddr_chain);
  static void inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
  			 int destroy);
  #ifdef CONFIG_SYSCTL
  static int devinet_sysctl_register(struct in_device *idev);
  static void devinet_sysctl_unregister(struct in_device *idev);
  #else
  static int devinet_sysctl_register(struct in_device *idev)
  {
  	return 0;
  }
  static void devinet_sysctl_unregister(struct in_device *idev)
  {
  }
  #endif
  
  /* Locks all the inet devices. */
  
  static struct in_ifaddr *inet_alloc_ifa(void)
  {
  	return kzalloc(sizeof(struct in_ifaddr), GFP_KERNEL);
  }
  
  static void inet_rcu_free_ifa(struct rcu_head *head)
  {
  	struct in_ifaddr *ifa = container_of(head, struct in_ifaddr, rcu_head);
  	if (ifa->ifa_dev)
  		in_dev_put(ifa->ifa_dev);
  	kfree(ifa);
  }
  
  static void inet_free_ifa(struct in_ifaddr *ifa)
  {
  	call_rcu(&ifa->rcu_head, inet_rcu_free_ifa);
  }
  
  void in_dev_finish_destroy(struct in_device *idev)
  {
  	struct net_device *dev = idev->dev;
  
  	WARN_ON(idev->ifa_list);
  	WARN_ON(idev->mc_list);
  	kfree(rcu_dereference_protected(idev->mc_hash, 1));
  #ifdef NET_REFCNT_DEBUG
  	pr_debug("%s: %p=%s\n", __func__, idev, dev ? dev->name : "NIL");
  #endif
  	dev_put(dev);
  	if (!idev->dead)
  		pr_err("Freeing alive in_device %p\n", idev);
  	else
  		kfree(idev);
  }
  EXPORT_SYMBOL(in_dev_finish_destroy);
  
  static struct in_device *inetdev_init(struct net_device *dev)
  {
  	struct in_device *in_dev;
  	int err = -ENOMEM;
  
  	ASSERT_RTNL();
  
  	in_dev = kzalloc(sizeof(*in_dev), GFP_KERNEL);
  	if (!in_dev)
  		goto out;
  	memcpy(&in_dev->cnf, dev_net(dev)->ipv4.devconf_dflt,
  			sizeof(in_dev->cnf));
  	in_dev->cnf.sysctl = NULL;
  	in_dev->dev = dev;
  	in_dev->arp_parms = neigh_parms_alloc(dev, &arp_tbl);
  	if (!in_dev->arp_parms)
  		goto out_kfree;
  	if (IPV4_DEVCONF(in_dev->cnf, FORWARDING))
  		dev_disable_lro(dev);
  	/* Reference in_dev->dev */
  	dev_hold(dev);
  	/* Account for reference dev->ip_ptr (below) */
  	in_dev_hold(in_dev);
  
  	err = devinet_sysctl_register(in_dev);
  	if (err) {
  		in_dev->dead = 1;
  		in_dev_put(in_dev);
  		in_dev = NULL;
  		goto out;
  	}
  	ip_mc_init_dev(in_dev);
  	if (dev->flags & IFF_UP)
  		ip_mc_up(in_dev);
  
  	/* we can receive as soon as ip_ptr is set -- do this last */
  	rcu_assign_pointer(dev->ip_ptr, in_dev);
  out:
  	return in_dev ?: ERR_PTR(err);
  out_kfree:
  	kfree(in_dev);
  	in_dev = NULL;
  	goto out;
  }
  
  static void in_dev_rcu_put(struct rcu_head *head)
  {
  	struct in_device *idev = container_of(head, struct in_device, rcu_head);
  	in_dev_put(idev);
  }
  
  static void inetdev_destroy(struct in_device *in_dev)
  {
  	struct in_ifaddr *ifa;
  	struct net_device *dev;
  
  	ASSERT_RTNL();
  
  	dev = in_dev->dev;
  
  	in_dev->dead = 1;
  
  	ip_mc_destroy_dev(in_dev);
  
  	while ((ifa = in_dev->ifa_list) != NULL) {
  		inet_del_ifa(in_dev, &in_dev->ifa_list, 0);
  		inet_free_ifa(ifa);
  	}
  
  	RCU_INIT_POINTER(dev->ip_ptr, NULL);
  
  	devinet_sysctl_unregister(in_dev);
  	neigh_parms_release(&arp_tbl, in_dev->arp_parms);
  	arp_ifdown(dev);
  
  	call_rcu(&in_dev->rcu_head, in_dev_rcu_put);
  }
  
  int inet_addr_onlink(struct in_device *in_dev, __be32 a, __be32 b)
  {
  	rcu_read_lock();
  	for_primary_ifa(in_dev) {
  		if (inet_ifa_match(a, ifa)) {
  			if (!b || inet_ifa_match(b, ifa)) {
  				rcu_read_unlock();
  				return 1;
  			}
  		}
  	} endfor_ifa(in_dev);
  	rcu_read_unlock();
  	return 0;
  }
  
  static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
  			 int destroy, struct nlmsghdr *nlh, u32 portid)
  {
  	struct in_ifaddr *promote = NULL;
  	struct in_ifaddr *ifa, *ifa1 = *ifap;
  	struct in_ifaddr *last_prim = in_dev->ifa_list;
  	struct in_ifaddr *prev_prom = NULL;
  	int do_promote = IN_DEV_PROMOTE_SECONDARIES(in_dev);
  
  	ASSERT_RTNL();
  
  	if (in_dev->dead)
  		goto no_promotions;
  
  	/* 1. Deleting primary ifaddr forces deletion all secondaries
  	 * unless alias promotion is set
  	 **/
  
  	if (!(ifa1->ifa_flags & IFA_F_SECONDARY)) {
  		struct in_ifaddr **ifap1 = &ifa1->ifa_next;
  
  		while ((ifa = *ifap1) != NULL) {
  			if (!(ifa->ifa_flags & IFA_F_SECONDARY) &&
  			    ifa1->ifa_scope <= ifa->ifa_scope)
  				last_prim = ifa;
  
  			if (!(ifa->ifa_flags & IFA_F_SECONDARY) ||
  			    ifa1->ifa_mask != ifa->ifa_mask ||
  			    !inet_ifa_match(ifa1->ifa_address, ifa)) {
  				ifap1 = &ifa->ifa_next;
  				prev_prom = ifa;
  				continue;
  			}
  
  			if (!do_promote) {
  				inet_hash_remove(ifa);
  				*ifap1 = ifa->ifa_next;
  
  				rtmsg_ifa(RTM_DELADDR, ifa, nlh, portid);
  				blocking_notifier_call_chain(&inetaddr_chain,
  						NETDEV_DOWN, ifa);
  				inet_free_ifa(ifa);
  			} else {
  				promote = ifa;
  				break;
  			}
  		}
  	}
  
  	/* On promotion all secondaries from subnet are changing
  	 * the primary IP, we must remove all their routes silently
  	 * and later to add them back with new prefsrc. Do this
  	 * while all addresses are on the device list.
  	 */
  	for (ifa = promote; ifa; ifa = ifa->ifa_next) {
  		if (ifa1->ifa_mask == ifa->ifa_mask &&
  		    inet_ifa_match(ifa1->ifa_address, ifa))
  			fib_del_ifaddr(ifa, ifa1);
  	}
  
  no_promotions:
  	/* 2. Unlink it */
  
  	*ifap = ifa1->ifa_next;
  	inet_hash_remove(ifa1);
  
  	/* 3. Announce address deletion */
  
  	/* Send message first, then call notifier.
  	   At first sight, FIB update triggered by notifier
  	   will refer to already deleted ifaddr, that could confuse
  	   netlink listeners. It is not true: look, gated sees
  	   that route deleted and if it still thinks that ifaddr
  	   is valid, it will try to restore deleted routes... Grr.
  	   So that, this order is correct.
  	 */
  	rtmsg_ifa(RTM_DELADDR, ifa1, nlh, portid);
  	blocking_notifier_call_chain(&inetaddr_chain, NETDEV_DOWN, ifa1);
  
  	if (promote) {
  		struct in_ifaddr *next_sec = promote->ifa_next;
  
  		if (prev_prom) {
  			prev_prom->ifa_next = promote->ifa_next;
  			promote->ifa_next = last_prim->ifa_next;
  			last_prim->ifa_next = promote;
  		}
  
  		promote->ifa_flags &= ~IFA_F_SECONDARY;
  		rtmsg_ifa(RTM_NEWADDR, promote, nlh, portid);
  		blocking_notifier_call_chain(&inetaddr_chain,
  				NETDEV_UP, promote);
  		for (ifa = next_sec; ifa; ifa = ifa->ifa_next) {
  			if (ifa1->ifa_mask != ifa->ifa_mask ||
  			    !inet_ifa_match(ifa1->ifa_address, ifa))
  					continue;
  			fib_add_ifaddr(ifa);
  		}
  
  	}
  	if (destroy)
  		inet_free_ifa(ifa1);
  }
  
  static void inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
  			 int destroy)
  {
  	__inet_del_ifa(in_dev, ifap, destroy, NULL, 0);
  }
  
  static void check_lifetime(struct work_struct *work);
  
  static DECLARE_DELAYED_WORK(check_lifetime_work, check_lifetime);
  
  static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
  			     u32 portid)
  {
  	struct in_device *in_dev = ifa->ifa_dev;
  	struct in_ifaddr *ifa1, **ifap, **last_primary;
  
  	ASSERT_RTNL();
  
  	if (!ifa->ifa_local) {
  		inet_free_ifa(ifa);
  		return 0;
  	}
  
  	ifa->ifa_flags &= ~IFA_F_SECONDARY;
  	last_primary = &in_dev->ifa_list;
  
  	for (ifap = &in_dev->ifa_list; (ifa1 = *ifap) != NULL;
  	     ifap = &ifa1->ifa_next) {
  		if (!(ifa1->ifa_flags & IFA_F_SECONDARY) &&
  		    ifa->ifa_scope <= ifa1->ifa_scope)
  			last_primary = &ifa1->ifa_next;
  		if (ifa1->ifa_mask == ifa->ifa_mask &&
  		    inet_ifa_match(ifa1->ifa_address, ifa)) {
  			if (ifa1->ifa_local == ifa->ifa_local) {
  				inet_free_ifa(ifa);
  				return -EEXIST;
  			}
  			if (ifa1->ifa_scope != ifa->ifa_scope) {
  				inet_free_ifa(ifa);
  				return -EINVAL;
  			}
  			ifa->ifa_flags |= IFA_F_SECONDARY;
  		}
  	}
  
  	if (!(ifa->ifa_flags & IFA_F_SECONDARY)) {
  		prandom_seed((__force u32) ifa->ifa_local);
  		ifap = last_primary;
  	}
  
  	ifa->ifa_next = *ifap;
  	*ifap = ifa;
  
  	inet_hash_insert(dev_net(in_dev->dev), ifa);
  
  	cancel_delayed_work(&check_lifetime_work);
  	queue_delayed_work(system_power_efficient_wq, &check_lifetime_work, 0);
  
  	/* Send message first, then call notifier.
  	   Notifier will trigger FIB update, so that
  	   listeners of netlink will know about new ifaddr */
  	rtmsg_ifa(RTM_NEWADDR, ifa, nlh, portid);
  	blocking_notifier_call_chain(&inetaddr_chain, NETDEV_UP, ifa);
  
  	return 0;
  }
  
  static int inet_insert_ifa(struct in_ifaddr *ifa)
  {
  	return __inet_insert_ifa(ifa, NULL, 0);
  }
  
  static int inet_set_ifa(struct net_device *dev, struct in_ifaddr *ifa)
  {
  	struct in_device *in_dev = __in_dev_get_rtnl(dev);
  
  	ASSERT_RTNL();
  
  	if (!in_dev) {
  		inet_free_ifa(ifa);
  		return -ENOBUFS;
  	}
  	ipv4_devconf_setall(in_dev);
  	neigh_parms_data_state_setall(in_dev->arp_parms);
  	if (ifa->ifa_dev != in_dev) {
  		WARN_ON(ifa->ifa_dev);
  		in_dev_hold(in_dev);
  		ifa->ifa_dev = in_dev;
  	}
  	if (ipv4_is_loopback(ifa->ifa_local))
  		ifa->ifa_scope = RT_SCOPE_HOST;
  	return inet_insert_ifa(ifa);
  }
  
  /* Caller must hold RCU or RTNL :
   * We dont take a reference on found in_device
   */
  struct in_device *inetdev_by_index(struct net *net, int ifindex)
  {
  	struct net_device *dev;
  	struct in_device *in_dev = NULL;
  
  	rcu_read_lock();
  	dev = dev_get_by_index_rcu(net, ifindex);
  	if (dev)
  		in_dev = rcu_dereference_rtnl(dev->ip_ptr);
  	rcu_read_unlock();
  	return in_dev;
  }
  EXPORT_SYMBOL(inetdev_by_index);
  
  /* Called only from RTNL semaphored context. No locks. */
  
  struct in_ifaddr *inet_ifa_byprefix(struct in_device *in_dev, __be32 prefix,
  				    __be32 mask)
  {
  	ASSERT_RTNL();
  
  	for_primary_ifa(in_dev) {
  		if (ifa->ifa_mask == mask && inet_ifa_match(prefix, ifa))
  			return ifa;
  	} endfor_ifa(in_dev);
  	return NULL;
  }
  
  static int ip_mc_config(struct sock *sk, bool join, const struct in_ifaddr *ifa)
  {
  	struct ip_mreqn mreq = {
  		.imr_multiaddr.s_addr = ifa->ifa_address,
  		.imr_ifindex = ifa->ifa_dev->dev->ifindex,
  	};
  	int ret;
  
  	ASSERT_RTNL();
  
  	lock_sock(sk);
  	if (join)
  		ret = ip_mc_join_group(sk, &mreq);
  	else
  		ret = ip_mc_leave_group(sk, &mreq);
  	release_sock(sk);
  
  	return ret;
  }
  
  static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh)
  {
  	struct net *net = sock_net(skb->sk);
  	struct nlattr *tb[IFA_MAX+1];
  	struct in_device *in_dev;
  	struct ifaddrmsg *ifm;
  	struct in_ifaddr *ifa, **ifap;
  	int err = -EINVAL;
  
  	ASSERT_RTNL();
  
  	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv4_policy);
  	if (err < 0)
  		goto errout;
  
  	ifm = nlmsg_data(nlh);
  	in_dev = inetdev_by_index(net, ifm->ifa_index);
  	if (!in_dev) {
  		err = -ENODEV;
  		goto errout;
  	}
  
  	for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
  	     ifap = &ifa->ifa_next) {
  		if (tb[IFA_LOCAL] &&
  		    ifa->ifa_local != nla_get_in_addr(tb[IFA_LOCAL]))
  			continue;
  
  		if (tb[IFA_LABEL] && nla_strcmp(tb[IFA_LABEL], ifa->ifa_label))
  			continue;
  
  		if (tb[IFA_ADDRESS] &&
  		    (ifm->ifa_prefixlen != ifa->ifa_prefixlen ||
  		    !inet_ifa_match(nla_get_in_addr(tb[IFA_ADDRESS]), ifa)))
  			continue;
  
  		if (ipv4_is_multicast(ifa->ifa_address))
  			ip_mc_config(net->ipv4.mc_autojoin_sk, false, ifa);
  		__inet_del_ifa(in_dev, ifap, 1, nlh, NETLINK_CB(skb).portid);
  		return 0;
  	}
  
  	err = -EADDRNOTAVAIL;
  errout:
  	return err;
  }
  
  #define INFINITY_LIFE_TIME	0xFFFFFFFF
  
  static void check_lifetime(struct work_struct *work)
  {
  	unsigned long now, next, next_sec, next_sched;
  	struct in_ifaddr *ifa;
  	struct hlist_node *n;
  	int i;
  
  	now = jiffies;
  	next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);
  
  	for (i = 0; i < IN4_ADDR_HSIZE; i++) {
  		bool change_needed = false;
  
  		rcu_read_lock();
  		hlist_for_each_entry_rcu(ifa, &inet_addr_lst[i], hash) {
  			unsigned long age;
  
  			if (ifa->ifa_flags & IFA_F_PERMANENT)
  				continue;
  
  			/* We try to batch several events at once. */
  			age = (now - ifa->ifa_tstamp +
  			       ADDRCONF_TIMER_FUZZ_MINUS) / HZ;
  
  			if (ifa->ifa_valid_lft != INFINITY_LIFE_TIME &&
  			    age >= ifa->ifa_valid_lft) {
  				change_needed = true;
  			} else if (ifa->ifa_preferred_lft ==
  				   INFINITY_LIFE_TIME) {
  				continue;
  			} else if (age >= ifa->ifa_preferred_lft) {
  				if (time_before(ifa->ifa_tstamp +
  						ifa->ifa_valid_lft * HZ, next))
  					next = ifa->ifa_tstamp +
  					       ifa->ifa_valid_lft * HZ;
  
  				if (!(ifa->ifa_flags & IFA_F_DEPRECATED))
  					change_needed = true;
  			} else if (time_before(ifa->ifa_tstamp +
  					       ifa->ifa_preferred_lft * HZ,
  					       next)) {
  				next = ifa->ifa_tstamp +
  				       ifa->ifa_preferred_lft * HZ;
  			}
  		}
  		rcu_read_unlock();
  		if (!change_needed)
  			continue;
  		rtnl_lock();
  		hlist_for_each_entry_safe(ifa, n, &inet_addr_lst[i], hash) {
  			unsigned long age;
  
  			if (ifa->ifa_flags & IFA_F_PERMANENT)
  				continue;
  
  			/* We try to batch several events at once. */
  			age = (now - ifa->ifa_tstamp +
  			       ADDRCONF_TIMER_FUZZ_MINUS) / HZ;
  
  			if (ifa->ifa_valid_lft != INFINITY_LIFE_TIME &&
  			    age >= ifa->ifa_valid_lft) {
  				struct in_ifaddr **ifap;
  
  				for (ifap = &ifa->ifa_dev->ifa_list;
  				     *ifap != NULL; ifap = &(*ifap)->ifa_next) {
  					if (*ifap == ifa) {
  						inet_del_ifa(ifa->ifa_dev,
  							     ifap, 1);
  						break;
  					}
  				}
  			} else if (ifa->ifa_preferred_lft !=
  				   INFINITY_LIFE_TIME &&
  				   age >= ifa->ifa_preferred_lft &&
  				   !(ifa->ifa_flags & IFA_F_DEPRECATED)) {
  				ifa->ifa_flags |= IFA_F_DEPRECATED;
  				rtmsg_ifa(RTM_NEWADDR, ifa, NULL, 0);
  			}
  		}
  		rtnl_unlock();
  	}
  
  	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;
  
  	now = jiffies;
  	/* And minimum interval is ADDRCONF_TIMER_FUZZ_MAX. */
  	if (time_before(next_sched, now + ADDRCONF_TIMER_FUZZ_MAX))
  		next_sched = now + ADDRCONF_TIMER_FUZZ_MAX;
  
  	queue_delayed_work(system_power_efficient_wq, &check_lifetime_work,
  			next_sched - now);
  }
  
  static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft,
  			     __u32 prefered_lft)
  {
  	unsigned long timeout;
  
  	ifa->ifa_flags &= ~(IFA_F_PERMANENT | IFA_F_DEPRECATED);
  
  	timeout = addrconf_timeout_fixup(valid_lft, HZ);
  	if (addrconf_finite_timeout(timeout))
  		ifa->ifa_valid_lft = timeout;
  	else
  		ifa->ifa_flags |= IFA_F_PERMANENT;
  
  	timeout = addrconf_timeout_fixup(prefered_lft, HZ);
  	if (addrconf_finite_timeout(timeout)) {
  		if (timeout == 0)
  			ifa->ifa_flags |= IFA_F_DEPRECATED;
  		ifa->ifa_preferred_lft = timeout;
  	}
  	ifa->ifa_tstamp = jiffies;
  	if (!ifa->ifa_cstamp)
  		ifa->ifa_cstamp = ifa->ifa_tstamp;
  }
  
  static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh,
  				       __u32 *pvalid_lft, __u32 *pprefered_lft)
  {
  	struct nlattr *tb[IFA_MAX+1];
  	struct in_ifaddr *ifa;
  	struct ifaddrmsg *ifm;
  	struct net_device *dev;
  	struct in_device *in_dev;
  	int err;
  
  	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv4_policy);
  	if (err < 0)
  		goto errout;
  
  	ifm = nlmsg_data(nlh);
  	err = -EINVAL;
  	if (ifm->ifa_prefixlen > 32 || !tb[IFA_LOCAL])
  		goto errout;
  
  	dev = __dev_get_by_index(net, ifm->ifa_index);
  	err = -ENODEV;
  	if (!dev)
  		goto errout;
  
  	in_dev = __in_dev_get_rtnl(dev);
  	err = -ENOBUFS;
  	if (!in_dev)
  		goto errout;
  
  	ifa = inet_alloc_ifa();
  	if (!ifa)
  		/*
  		 * A potential indev allocation can be left alive, it stays
  		 * assigned to its device and is destroy with it.
  		 */
  		goto errout;
  
  	ipv4_devconf_setall(in_dev);
  	neigh_parms_data_state_setall(in_dev->arp_parms);
  	in_dev_hold(in_dev);
  
  	if (!tb[IFA_ADDRESS])
  		tb[IFA_ADDRESS] = tb[IFA_LOCAL];
  
  	INIT_HLIST_NODE(&ifa->hash);
  	ifa->ifa_prefixlen = ifm->ifa_prefixlen;
  	ifa->ifa_mask = inet_make_mask(ifm->ifa_prefixlen);
  	ifa->ifa_flags = tb[IFA_FLAGS] ? nla_get_u32(tb[IFA_FLAGS]) :
  					 ifm->ifa_flags;
  	ifa->ifa_scope = ifm->ifa_scope;
  	ifa->ifa_dev = in_dev;
  
  	ifa->ifa_local = nla_get_in_addr(tb[IFA_LOCAL]);
  	ifa->ifa_address = nla_get_in_addr(tb[IFA_ADDRESS]);
  
  	if (tb[IFA_BROADCAST])
  		ifa->ifa_broadcast = nla_get_in_addr(tb[IFA_BROADCAST]);
  
  	if (tb[IFA_LABEL])
  		nla_strlcpy(ifa->ifa_label, tb[IFA_LABEL], IFNAMSIZ);
  	else
  		memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
  
  	if (tb[IFA_CACHEINFO]) {
  		struct ifa_cacheinfo *ci;
  
  		ci = nla_data(tb[IFA_CACHEINFO]);
  		if (!ci->ifa_valid || ci->ifa_prefered > ci->ifa_valid) {
  			err = -EINVAL;
  			goto errout_free;
  		}
  		*pvalid_lft = ci->ifa_valid;
  		*pprefered_lft = ci->ifa_prefered;
  	}
  
  	return ifa;
  
  errout_free:
  	inet_free_ifa(ifa);
  errout:
  	return ERR_PTR(err);
  }
  
  static struct in_ifaddr *find_matching_ifa(struct in_ifaddr *ifa)
  {
  	struct in_device *in_dev = ifa->ifa_dev;
  	struct in_ifaddr *ifa1, **ifap;
  
  	if (!ifa->ifa_local)
  		return NULL;
  
  	for (ifap = &in_dev->ifa_list; (ifa1 = *ifap) != NULL;
  	     ifap = &ifa1->ifa_next) {
  		if (ifa1->ifa_mask == ifa->ifa_mask &&
  		    inet_ifa_match(ifa1->ifa_address, ifa) &&
  		    ifa1->ifa_local == ifa->ifa_local)
  			return ifa1;
  	}
  	return NULL;
  }
  
  static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
  {
  	struct net *net = sock_net(skb->sk);
  	struct in_ifaddr *ifa;
  	struct in_ifaddr *ifa_existing;
  	__u32 valid_lft = INFINITY_LIFE_TIME;
  	__u32 prefered_lft = INFINITY_LIFE_TIME;
  
  	ASSERT_RTNL();
  
  	ifa = rtm_to_ifaddr(net, nlh, &valid_lft, &prefered_lft);
  	if (IS_ERR(ifa))
  		return PTR_ERR(ifa);
  
  	ifa_existing = find_matching_ifa(ifa);
  	if (!ifa_existing) {
  		/* It would be best to check for !NLM_F_CREATE here but
  		 * userspace already relies on not having to provide this.
  		 */
  		set_ifa_lifetime(ifa, valid_lft, prefered_lft);
  		if (ifa->ifa_flags & IFA_F_MCAUTOJOIN) {
  			int ret = ip_mc_config(net->ipv4.mc_autojoin_sk,
  					       true, ifa);
  
  			if (ret < 0) {
  				inet_free_ifa(ifa);
  				return ret;
  			}
  		}
  		return __inet_insert_ifa(ifa, nlh, NETLINK_CB(skb).portid);
  	} else {
  		inet_free_ifa(ifa);
  
  		if (nlh->nlmsg_flags & NLM_F_EXCL ||
  		    !(nlh->nlmsg_flags & NLM_F_REPLACE))
  			return -EEXIST;
  		ifa = ifa_existing;
  		set_ifa_lifetime(ifa, valid_lft, prefered_lft);
  		cancel_delayed_work(&check_lifetime_work);
  		queue_delayed_work(system_power_efficient_wq,
  				&check_lifetime_work, 0);
  		rtmsg_ifa(RTM_NEWADDR, ifa, nlh, NETLINK_CB(skb).portid);
  	}
  	return 0;
  }
  
  /*
   *	Determine a default network mask, based on the IP address.
   */
  
  static int inet_abc_len(__be32 addr)
  {
  	int rc = -1;	/* Something else, probably a multicast. */
  
  	if (ipv4_is_zeronet(addr))
  		rc = 0;
  	else {
  		__u32 haddr = ntohl(addr);
  
  		if (IN_CLASSA(haddr))
  			rc = 8;
  		else if (IN_CLASSB(haddr))
  			rc = 16;
  		else if (IN_CLASSC(haddr))
  			rc = 24;
  	}
  
  	return rc;
  }
  
  
  int devinet_ioctl(struct net *net, unsigned int cmd, void __user *arg)
  {
  	struct ifreq ifr;
  	struct sockaddr_in sin_orig;
  	struct sockaddr_in *sin = (struct sockaddr_in *)&ifr.ifr_addr;
  	struct in_device *in_dev;
  	struct in_ifaddr **ifap = NULL;
  	struct in_ifaddr *ifa = NULL;
  	struct net_device *dev;
  	char *colon;
  	int ret = -EFAULT;
  	int tryaddrmatch = 0;
  
  	/*
  	 *	Fetch the caller's info block into kernel space
  	 */
  
  	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
  		goto out;
  	ifr.ifr_name[IFNAMSIZ - 1] = 0;
  
  	/* save original address for comparison */
  	memcpy(&sin_orig, sin, sizeof(*sin));
  
  	colon = strchr(ifr.ifr_name, ':');
  	if (colon)
  		*colon = 0;
  
  	dev_load(net, ifr.ifr_name);
  
  	switch (cmd) {
  	case SIOCGIFADDR:	/* Get interface address */
  	case SIOCGIFBRDADDR:	/* Get the broadcast address */
  	case SIOCGIFDSTADDR:	/* Get the destination address */
  	case SIOCGIFNETMASK:	/* Get the netmask for the interface */
  		/* Note that these ioctls will not sleep,
  		   so that we do not impose a lock.
  		   One day we will be forced to put shlock here (I mean SMP)
  		 */
  		tryaddrmatch = (sin_orig.sin_family == AF_INET);
  		memset(sin, 0, sizeof(*sin));
  		sin->sin_family = AF_INET;
  		break;
  
  	case SIOCSIFFLAGS:
  		ret = -EPERM;
  		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
  			goto out;
  		break;
  	case SIOCSIFADDR:	/* Set interface address (and family) */
  	case SIOCSIFBRDADDR:	/* Set the broadcast address */
  	case SIOCSIFDSTADDR:	/* Set the destination address */
  	case SIOCSIFNETMASK: 	/* Set the netmask for the interface */
  		ret = -EPERM;
  		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
  			goto out;
  		ret = -EINVAL;
  		if (sin->sin_family != AF_INET)
  			goto out;
  		break;
  	default:
  		ret = -EINVAL;
  		goto out;
  	}
  
  	rtnl_lock();
  
  	ret = -ENODEV;
  	dev = __dev_get_by_name(net, ifr.ifr_name);
  	if (!dev)
  		goto done;
  
  	if (colon)
  		*colon = ':';
  
  	in_dev = __in_dev_get_rtnl(dev);
  	if (in_dev) {
  		if (tryaddrmatch) {
  			/* Matthias Andree */
  			/* compare label and address (4.4BSD style) */
  			/* note: we only do this for a limited set of ioctls
  			   and only if the original address family was AF_INET.
  			   This is checked above. */
  			for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
  			     ifap = &ifa->ifa_next) {
  				if (!strcmp(ifr.ifr_name, ifa->ifa_label) &&
  				    sin_orig.sin_addr.s_addr ==
  							ifa->ifa_local) {
  					break; /* found */
  				}
  			}
  		}
  		/* we didn't get a match, maybe the application is
  		   4.3BSD-style and passed in junk so we fall back to
  		   comparing just the label */
  		if (!ifa) {
  			for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
  			     ifap = &ifa->ifa_next)
  				if (!strcmp(ifr.ifr_name, ifa->ifa_label))
  					break;
  		}
  	}
  
  	ret = -EADDRNOTAVAIL;
  	if (!ifa && cmd != SIOCSIFADDR && cmd != SIOCSIFFLAGS)
  		goto done;
  
  	switch (cmd) {
  	case SIOCGIFADDR:	/* Get interface address */
  		sin->sin_addr.s_addr = ifa->ifa_local;
  		goto rarok;
  
  	case SIOCGIFBRDADDR:	/* Get the broadcast address */
  		sin->sin_addr.s_addr = ifa->ifa_broadcast;
  		goto rarok;
  
  	case SIOCGIFDSTADDR:	/* Get the destination address */
  		sin->sin_addr.s_addr = ifa->ifa_address;
  		goto rarok;
  
  	case SIOCGIFNETMASK:	/* Get the netmask for the interface */
  		sin->sin_addr.s_addr = ifa->ifa_mask;
  		goto rarok;
  
  	case SIOCSIFFLAGS:
  		if (colon) {
  			ret = -EADDRNOTAVAIL;
  			if (!ifa)
  				break;
  			ret = 0;
  			if (!(ifr.ifr_flags & IFF_UP))
  				inet_del_ifa(in_dev, ifap, 1);
  			break;
  		}
  		ret = dev_change_flags(dev, ifr.ifr_flags);
  		break;
  
  	case SIOCSIFADDR:	/* Set interface address (and family) */
  		ret = -EINVAL;
  		if (inet_abc_len(sin->sin_addr.s_addr) < 0)
  			break;
  
  		if (!ifa) {
  			ret = -ENOBUFS;
  			ifa = inet_alloc_ifa();
  			if (!ifa)
  				break;
  			INIT_HLIST_NODE(&ifa->hash);
  			if (colon)
  				memcpy(ifa->ifa_label, ifr.ifr_name, IFNAMSIZ);
  			else
  				memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
  		} else {
  			ret = 0;
  			if (ifa->ifa_local == sin->sin_addr.s_addr)
  				break;
  			inet_del_ifa(in_dev, ifap, 0);
  			ifa->ifa_broadcast = 0;
  			ifa->ifa_scope = 0;
  		}
  
  		ifa->ifa_address = ifa->ifa_local = sin->sin_addr.s_addr;
  
  		if (!(dev->flags & IFF_POINTOPOINT)) {
  			ifa->ifa_prefixlen = inet_abc_len(ifa->ifa_address);
  			ifa->ifa_mask = inet_make_mask(ifa->ifa_prefixlen);
  			if ((dev->flags & IFF_BROADCAST) &&
  			    ifa->ifa_prefixlen < 31)
  				ifa->ifa_broadcast = ifa->ifa_address |
  						     ~ifa->ifa_mask;
  		} else {
  			ifa->ifa_prefixlen = 32;
  			ifa->ifa_mask = inet_make_mask(32);
  		}
  		set_ifa_lifetime(ifa, INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
  		ret = inet_set_ifa(dev, ifa);
  		break;
  
  	case SIOCSIFBRDADDR:	/* Set the broadcast address */
  		ret = 0;
  		if (ifa->ifa_broadcast != sin->sin_addr.s_addr) {
  			inet_del_ifa(in_dev, ifap, 0);
  			ifa->ifa_broadcast = sin->sin_addr.s_addr;
  			inet_insert_ifa(ifa);
  		}
  		break;
  
  	case SIOCSIFDSTADDR:	/* Set the destination address */
  		ret = 0;
  		if (ifa->ifa_address == sin->sin_addr.s_addr)
  			break;
  		ret = -EINVAL;
  		if (inet_abc_len(sin->sin_addr.s_addr) < 0)
  			break;
  		ret = 0;
  		inet_del_ifa(in_dev, ifap, 0);
  		ifa->ifa_address = sin->sin_addr.s_addr;
  		inet_insert_ifa(ifa);
  		break;
  
  	case SIOCSIFNETMASK: 	/* Set the netmask for the interface */
  
  		/*
  		 *	The mask we set must be legal.
  		 */
  		ret = -EINVAL;
  		if (bad_mask(sin->sin_addr.s_addr, 0))
  			break;
  		ret = 0;
  		if (ifa->ifa_mask != sin->sin_addr.s_addr) {
  			__be32 old_mask = ifa->ifa_mask;
  			inet_del_ifa(in_dev, ifap, 0);
  			ifa->ifa_mask = sin->sin_addr.s_addr;
  			ifa->ifa_prefixlen = inet_mask_len(ifa->ifa_mask);
  
  			/* See if current broadcast address matches
  			 * with current netmask, then recalculate
  			 * the broadcast address. Otherwise it's a
  			 * funny address, so don't touch it since
  			 * the user seems to know what (s)he's doing...
  			 */
  			if ((dev->flags & IFF_BROADCAST) &&
  			    (ifa->ifa_prefixlen < 31) &&
  			    (ifa->ifa_broadcast ==
  			     (ifa->ifa_local|~old_mask))) {
  				ifa->ifa_broadcast = (ifa->ifa_local |
  						      ~sin->sin_addr.s_addr);
  			}
  			inet_insert_ifa(ifa);
  		}
  		break;
  	}
  done:
  	rtnl_unlock();
  out:
  	return ret;
  rarok:
  	rtnl_unlock();
  	ret = copy_to_user(arg, &ifr, sizeof(struct ifreq)) ? -EFAULT : 0;
  	goto out;
  }
  
  static int inet_gifconf(struct net_device *dev, char __user *buf, int len)
  {
  	struct in_device *in_dev = __in_dev_get_rtnl(dev);
  	struct in_ifaddr *ifa;
  	struct ifreq ifr;
  	int done = 0;
  
  	if (!in_dev)
  		goto out;
  
  	for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
  		if (!buf) {
  			done += sizeof(ifr);
  			continue;
  		}
  		if (len < (int) sizeof(ifr))
  			break;
  		memset(&ifr, 0, sizeof(struct ifreq));
  		strcpy(ifr.ifr_name, ifa->ifa_label);
  
  		(*(struct sockaddr_in *)&ifr.ifr_addr).sin_family = AF_INET;
  		(*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr.s_addr =
  								ifa->ifa_local;
  
  		if (copy_to_user(buf, &ifr, sizeof(struct ifreq))) {
  			done = -EFAULT;
  			break;
  		}
  		buf  += sizeof(struct ifreq);
  		len  -= sizeof(struct ifreq);
  		done += sizeof(struct ifreq);
  	}
  out:
  	return done;
  }
  
  __be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope)
  {
  	__be32 addr = 0;
  	struct in_device *in_dev;
  	struct net *net = dev_net(dev);
  	int master_idx;
  
  	rcu_read_lock();
  	in_dev = __in_dev_get_rcu(dev);
  	if (!in_dev)
  		goto no_in_dev;
  
  	for_primary_ifa(in_dev) {
  		if (ifa->ifa_scope > scope)
  			continue;
  		if (!dst || inet_ifa_match(dst, ifa)) {
  			addr = ifa->ifa_local;
  			break;
  		}
  		if (!addr)
  			addr = ifa->ifa_local;
  	} endfor_ifa(in_dev);
  
  	if (addr)
  		goto out_unlock;
  no_in_dev:
  	master_idx = l3mdev_master_ifindex_rcu(dev);
  
  	/* For VRFs, the VRF device takes the place of the loopback device,
  	 * with addresses on it being preferred.  Note in such cases the
  	 * loopback device will be among the devices that fail the master_idx
  	 * equality check in the loop below.
  	 */
  	if (master_idx &&
  	    (dev = dev_get_by_index_rcu(net, master_idx)) &&
  	    (in_dev = __in_dev_get_rcu(dev))) {
  		for_primary_ifa(in_dev) {
  			if (ifa->ifa_scope != RT_SCOPE_LINK &&
  			    ifa->ifa_scope <= scope) {
  				addr = ifa->ifa_local;
  				goto out_unlock;
  			}
  		} endfor_ifa(in_dev);
  	}
  
  	/* Not loopback addresses on loopback should be preferred
  	   in this case. It is important that lo is the first interface
  	   in dev_base list.
  	 */
  	for_each_netdev_rcu(net, dev) {
  		if (l3mdev_master_ifindex_rcu(dev) != master_idx)
  			continue;
  
  		in_dev = __in_dev_get_rcu(dev);
  		if (!in_dev)
  			continue;
  
  		for_primary_ifa(in_dev) {
  			if (ifa->ifa_scope != RT_SCOPE_LINK &&
  			    ifa->ifa_scope <= scope) {
  				addr = ifa->ifa_local;
  				goto out_unlock;
  			}
  		} endfor_ifa(in_dev);
  	}
  out_unlock:
  	rcu_read_unlock();
  	return addr;
  }
  EXPORT_SYMBOL(inet_select_addr);
  
  static __be32 confirm_addr_indev(struct in_device *in_dev, __be32 dst,
  			      __be32 local, int scope)
  {
  	int same = 0;
  	__be32 addr = 0;
  
  	for_ifa(in_dev) {
  		if (!addr &&
  		    (local == ifa->ifa_local || !local) &&
  		    ifa->ifa_scope <= scope) {
  			addr = ifa->ifa_local;
  			if (same)
  				break;
  		}
  		if (!same) {
  			same = (!local || inet_ifa_match(local, ifa)) &&
  				(!dst || inet_ifa_match(dst, ifa));
  			if (same && addr) {
  				if (local || !dst)
  					break;
  				/* Is the selected addr into dst subnet? */
  				if (inet_ifa_match(addr, ifa))
  					break;
  				/* No, then can we use new local src? */
  				if (ifa->ifa_scope <= scope) {
  					addr = ifa->ifa_local;
  					break;
  				}
  				/* search for large dst subnet for addr */
  				same = 0;
  			}
  		}
  	} endfor_ifa(in_dev);
  
  	return same ? addr : 0;
  }
  
  /*
   * Confirm that local IP address exists using wildcards:
   * - net: netns to check, cannot be NULL
   * - in_dev: only on this interface, NULL=any interface
   * - dst: only in the same subnet as dst, 0=any dst
   * - local: address, 0=autoselect the local address
   * - scope: maximum allowed scope value for the local address
   */
  __be32 inet_confirm_addr(struct net *net, struct in_device *in_dev,
  			 __be32 dst, __be32 local, int scope)
  {
  	__be32 addr = 0;
  	struct net_device *dev;
  
  	if (in_dev)
  		return confirm_addr_indev(in_dev, dst, local, scope);
  
  	rcu_read_lock();
  	for_each_netdev_rcu(net, dev) {
  		in_dev = __in_dev_get_rcu(dev);
  		if (in_dev) {
  			addr = confirm_addr_indev(in_dev, dst, local, scope);
  			if (addr)
  				break;
  		}
  	}
  	rcu_read_unlock();
  
  	return addr;
  }
  EXPORT_SYMBOL(inet_confirm_addr);
  
  /*
   *	Device notifier
   */
  
  int register_inetaddr_notifier(struct notifier_block *nb)
  {
  	return blocking_notifier_chain_register(&inetaddr_chain, nb);
  }
  EXPORT_SYMBOL(register_inetaddr_notifier);
  
  int unregister_inetaddr_notifier(struct notifier_block *nb)
  {
  	return blocking_notifier_chain_unregister(&inetaddr_chain, nb);
  }
  EXPORT_SYMBOL(unregister_inetaddr_notifier);
  
  /* Rename ifa_labels for a device name change. Make some effort to preserve
   * existing alias numbering and to create unique labels if possible.
  */
  static void inetdev_changename(struct net_device *dev, struct in_device *in_dev)
  {
  	struct in_ifaddr *ifa;
  	int named = 0;
  
  	for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
  		char old[IFNAMSIZ], *dot;
  
  		memcpy(old, ifa->ifa_label, IFNAMSIZ);
  		memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
  		if (named++ == 0)
  			goto skip;
  		dot = strchr(old, ':');
  		if (!dot) {
  			sprintf(old, ":%d", named);
  			dot = old;
  		}
  		if (strlen(dot) + strlen(dev->name) < IFNAMSIZ)
  			strcat(ifa->ifa_label, dot);
  		else
  			strcpy(ifa->ifa_label + (IFNAMSIZ - strlen(dot) - 1), dot);
  skip:
  		rtmsg_ifa(RTM_NEWADDR, ifa, NULL, 0);
  	}
  }
  
  static bool inetdev_valid_mtu(unsigned int mtu)
  {
  	return mtu >= 68;
  }
  
  static void inetdev_send_gratuitous_arp(struct net_device *dev,
  					struct in_device *in_dev)
  
  {
  	struct in_ifaddr *ifa;
  
  	for (ifa = in_dev->ifa_list; ifa;
  	     ifa = ifa->ifa_next) {
  		arp_send(ARPOP_REQUEST, ETH_P_ARP,
  			 ifa->ifa_local, dev,
  			 ifa->ifa_local, NULL,
  			 dev->dev_addr, NULL);
  	}
  }
  
  /* Called only under RTNL semaphore */
  
  static int inetdev_event(struct notifier_block *this, unsigned long event,
  			 void *ptr)
  {
  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
  	struct in_device *in_dev = __in_dev_get_rtnl(dev);
  
  	ASSERT_RTNL();
  
  	if (!in_dev) {
  		if (event == NETDEV_REGISTER) {
  			in_dev = inetdev_init(dev);
  			if (IS_ERR(in_dev))
  				return notifier_from_errno(PTR_ERR(in_dev));
  			if (dev->flags & IFF_LOOPBACK) {
  				IN_DEV_CONF_SET(in_dev, NOXFRM, 1);
  				IN_DEV_CONF_SET(in_dev, NOPOLICY, 1);
  			}
  		} else if (event == NETDEV_CHANGEMTU) {
  			/* Re-enabling IP */
  			if (inetdev_valid_mtu(dev->mtu))
  				in_dev = inetdev_init(dev);
  		}
  		goto out;
  	}
  
  	switch (event) {
  	case NETDEV_REGISTER:
  		pr_debug("%s: bug\n", __func__);
  		RCU_INIT_POINTER(dev->ip_ptr, NULL);
  		break;
  	case NETDEV_UP:
  		if (!inetdev_valid_mtu(dev->mtu))
  			break;
  		if (dev->flags & IFF_LOOPBACK) {
  			struct in_ifaddr *ifa = inet_alloc_ifa();
  
  			if (ifa) {
  				INIT_HLIST_NODE(&ifa->hash);
  				ifa->ifa_local =
  				  ifa->ifa_address = htonl(INADDR_LOOPBACK);
  				ifa->ifa_prefixlen = 8;
  				ifa->ifa_mask = inet_make_mask(8);
  				in_dev_hold(in_dev);
  				ifa->ifa_dev = in_dev;
  				ifa->ifa_scope = RT_SCOPE_HOST;
  				memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
  				set_ifa_lifetime(ifa, INFINITY_LIFE_TIME,
  						 INFINITY_LIFE_TIME);
  				ipv4_devconf_setall(in_dev);
  				neigh_parms_data_state_setall(in_dev->arp_parms);
  				inet_insert_ifa(ifa);
  			}
  		}
  		ip_mc_up(in_dev);
  		/* fall through */
  	case NETDEV_CHANGEADDR:
  		if (!IN_DEV_ARP_NOTIFY(in_dev))
  			break;
  		/* fall through */
  	case NETDEV_NOTIFY_PEERS:
  		/* Send gratuitous ARP to notify of link change */
  		inetdev_send_gratuitous_arp(dev, in_dev);
  		break;
  	case NETDEV_DOWN:
  		ip_mc_down(in_dev);
  		break;
  	case NETDEV_PRE_TYPE_CHANGE:
  		ip_mc_unmap(in_dev);
  		break;
  	case NETDEV_POST_TYPE_CHANGE:
  		ip_mc_remap(in_dev);
  		break;
  	case NETDEV_CHANGEMTU:
  		if (inetdev_valid_mtu(dev->mtu))
  			break;
  		/* disable IP when MTU is not enough */
  	case NETDEV_UNREGISTER:
  		inetdev_destroy(in_dev);
  		break;
  	case NETDEV_CHANGENAME:
  		/* Do not notify about label change, this event is
  		 * not interesting to applications using netlink.
  		 */
  		inetdev_changename(dev, in_dev);
  
  		devinet_sysctl_unregister(in_dev);
  		devinet_sysctl_register(in_dev);
  		break;
  	}
  out:
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block ip_netdev_notifier = {
  	.notifier_call = inetdev_event,
  };
  
  static size_t inet_nlmsg_size(void)
  {
  	return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
  	       + nla_total_size(4) /* IFA_ADDRESS */
  	       + nla_total_size(4) /* IFA_LOCAL */
  	       + nla_total_size(4) /* IFA_BROADCAST */
  	       + nla_total_size(IFNAMSIZ) /* IFA_LABEL */
  	       + nla_total_size(4)  /* IFA_FLAGS */
  	       + nla_total_size(sizeof(struct ifa_cacheinfo)); /* IFA_CACHEINFO */
  }
  
  static inline u32 cstamp_delta(unsigned long cstamp)
  {
  	return (cstamp - INITIAL_JIFFIES) * 100UL / HZ;
  }
  
  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 int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
  			    u32 portid, u32 seq, int event, unsigned int flags)
  {
  	struct ifaddrmsg *ifm;
  	struct nlmsghdr  *nlh;
  	u32 preferred, valid;
  
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*ifm), flags);
  	if (!nlh)
  		return -EMSGSIZE;
  
  	ifm = nlmsg_data(nlh);
  	ifm->ifa_family = AF_INET;
  	ifm->ifa_prefixlen = ifa->ifa_prefixlen;
  	ifm->ifa_flags = ifa->ifa_flags;
  	ifm->ifa_scope = ifa->ifa_scope;
  	ifm->ifa_index = ifa->ifa_dev->dev->ifindex;
  
  	if (!(ifm->ifa_flags & IFA_F_PERMANENT)) {
  		preferred = ifa->ifa_preferred_lft;
  		valid = ifa->ifa_valid_lft;
  		if (preferred != INFINITY_LIFE_TIME) {
  			long tval = (jiffies - ifa->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 ((ifa->ifa_address &&
  	     nla_put_in_addr(skb, IFA_ADDRESS, ifa->ifa_address)) ||
  	    (ifa->ifa_local &&
  	     nla_put_in_addr(skb, IFA_LOCAL, ifa->ifa_local)) ||
  	    (ifa->ifa_broadcast &&
  	     nla_put_in_addr(skb, IFA_BROADCAST, ifa->ifa_broadcast)) ||
  	    (ifa->ifa_label[0] &&
  	     nla_put_string(skb, IFA_LABEL, ifa->ifa_label)) ||
  	    nla_put_u32(skb, IFA_FLAGS, ifa->ifa_flags) ||
  	    put_cacheinfo(skb, ifa->ifa_cstamp, ifa->ifa_tstamp,
  			  preferred, valid))
  		goto nla_put_failure;
  
  	nlmsg_end(skb, nlh);
  	return 0;
  
  nla_put_failure:
  	nlmsg_cancel(skb, nlh);
  	return -EMSGSIZE;
  }
  
  static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	struct net *net = sock_net(skb->sk);
  	int h, s_h;
  	int idx, s_idx;
  	int ip_idx, s_ip_idx;
  	struct net_device *dev;
  	struct in_device *in_dev;
  	struct in_ifaddr *ifa;
  	struct hlist_head *head;
  
  	s_h = cb->args[0];
  	s_idx = idx = cb->args[1];
  	s_ip_idx = ip_idx = cb->args[2];
  
  	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->ipv4.dev_addr_genid) ^
  			  net->dev_base_seq;
  		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;
  			in_dev = __in_dev_get_rcu(dev);
  			if (!in_dev)
  				goto cont;
  
  			for (ifa = in_dev->ifa_list, ip_idx = 0; ifa;
  			     ifa = ifa->ifa_next, ip_idx++) {
  				if (ip_idx < s_ip_idx)
  					continue;
  				if (inet_fill_ifaddr(skb, ifa,
  					     NETLINK_CB(cb->skb).portid,
  					     cb->nlh->nlmsg_seq,
  					     RTM_NEWADDR, NLM_F_MULTI) < 0) {
  					rcu_read_unlock();
  					goto done;
  				}
  				nl_dump_check_consistent(cb, nlmsg_hdr(skb));
  			}
  cont:
  			idx++;
  		}
  		rcu_read_unlock();
  	}
  
  done:
  	cb->args[0] = h;
  	cb->args[1] = idx;
  	cb->args[2] = ip_idx;
  
  	return skb->len;
  }
  
  static void rtmsg_ifa(int event, struct in_ifaddr *ifa, struct nlmsghdr *nlh,
  		      u32 portid)
  {
  	struct sk_buff *skb;
  	u32 seq = nlh ? nlh->nlmsg_seq : 0;
  	int err = -ENOBUFS;
  	struct net *net;
  
  	net = dev_net(ifa->ifa_dev->dev);
  	skb = nlmsg_new(inet_nlmsg_size(), GFP_KERNEL);
  	if (!skb)
  		goto errout;
  
  	err = inet_fill_ifaddr(skb, ifa, portid, seq, event, 0);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet_nlmsg_size() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout;
  	}
  	rtnl_notify(skb, net, portid, RTNLGRP_IPV4_IFADDR, nlh, GFP_KERNEL);
  	return;
  errout:
  	if (err < 0)
  		rtnl_set_sk_err(net, RTNLGRP_IPV4_IFADDR, err);
  }
  
  static size_t inet_get_link_af_size(const struct net_device *dev,
  				    u32 ext_filter_mask)
  {
  	struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);
  
  	if (!in_dev)
  		return 0;
  
  	return nla_total_size(IPV4_DEVCONF_MAX * 4); /* IFLA_INET_CONF */
  }
  
  static int inet_fill_link_af(struct sk_buff *skb, const struct net_device *dev,
  			     u32 ext_filter_mask)
  {
  	struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);
  	struct nlattr *nla;
  	int i;
  
  	if (!in_dev)
  		return -ENODATA;
  
  	nla = nla_reserve(skb, IFLA_INET_CONF, IPV4_DEVCONF_MAX * 4);
  	if (!nla)
  		return -EMSGSIZE;
  
  	for (i = 0; i < IPV4_DEVCONF_MAX; i++)
  		((u32 *) nla_data(nla))[i] = in_dev->cnf.data[i];
  
  	return 0;
  }
  
  static const struct nla_policy inet_af_policy[IFLA_INET_MAX+1] = {
  	[IFLA_INET_CONF]	= { .type = NLA_NESTED },
  };
  
  static int inet_validate_link_af(const struct net_device *dev,
  				 const struct nlattr *nla)
  {
  	struct nlattr *a, *tb[IFLA_INET_MAX+1];
  	int err, rem;
  
  	if (dev && !__in_dev_get_rtnl(dev))
  		return -EAFNOSUPPORT;
  
  	err = nla_parse_nested(tb, IFLA_INET_MAX, nla, inet_af_policy);
  	if (err < 0)
  		return err;
  
  	if (tb[IFLA_INET_CONF]) {
  		nla_for_each_nested(a, tb[IFLA_INET_CONF], rem) {
  			int cfgid = nla_type(a);
  
  			if (nla_len(a) < 4)
  				return -EINVAL;
  
  			if (cfgid <= 0 || cfgid > IPV4_DEVCONF_MAX)
  				return -EINVAL;
  		}
  	}
  
  	return 0;
  }
  
  static int inet_set_link_af(struct net_device *dev, const struct nlattr *nla)
  {
  	struct in_device *in_dev = __in_dev_get_rtnl(dev);
  	struct nlattr *a, *tb[IFLA_INET_MAX+1];
  	int rem;
  
  	if (!in_dev)
  		return -EAFNOSUPPORT;
  
  	if (nla_parse_nested(tb, IFLA_INET_MAX, nla, NULL) < 0)
  		BUG();
  
  	if (tb[IFLA_INET_CONF]) {
  		nla_for_each_nested(a, tb[IFLA_INET_CONF], rem)
  			ipv4_devconf_set(in_dev, nla_type(a), nla_get_u32(a));
  	}
  
  	return 0;
  }
  
  static int inet_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);
  	if (all || type == NETCONFA_RP_FILTER)
  		size += nla_total_size(4);
  	if (all || type == NETCONFA_MC_FORWARDING)
  		size += nla_total_size(4);
  	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 inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
  				     struct ipv4_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_INET;
  
  	if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
  		goto nla_put_failure;
  
  	if ((all || type == NETCONFA_FORWARDING) &&
  	    nla_put_s32(skb, NETCONFA_FORWARDING,
  			IPV4_DEVCONF(*devconf, FORWARDING)) < 0)
  		goto nla_put_failure;
  	if ((all || type == NETCONFA_RP_FILTER) &&
  	    nla_put_s32(skb, NETCONFA_RP_FILTER,
  			IPV4_DEVCONF(*devconf, RP_FILTER)) < 0)
  		goto nla_put_failure;
  	if ((all || type == NETCONFA_MC_FORWARDING) &&
  	    nla_put_s32(skb, NETCONFA_MC_FORWARDING,
  			IPV4_DEVCONF(*devconf, MC_FORWARDING)) < 0)
  		goto nla_put_failure;
  	if ((all || type == NETCONFA_PROXY_NEIGH) &&
  	    nla_put_s32(skb, NETCONFA_PROXY_NEIGH,
  			IPV4_DEVCONF(*devconf, PROXY_ARP)) < 0)
  		goto nla_put_failure;
  	if ((all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) &&
  	    nla_put_s32(skb, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
  			IPV4_DEVCONF(*devconf, IGNORE_ROUTES_WITH_LINKDOWN)) < 0)
  		goto nla_put_failure;
  
  	nlmsg_end(skb, nlh);
  	return 0;
  
  nla_put_failure:
  	nlmsg_cancel(skb, nlh);
  	return -EMSGSIZE;
  }
  
  void inet_netconf_notify_devconf(struct net *net, int type, int ifindex,
  				 struct ipv4_devconf *devconf)
  {
  	struct sk_buff *skb;
  	int err = -ENOBUFS;
  
  	skb = nlmsg_new(inet_netconf_msgsize_devconf(type), GFP_KERNEL);
  	if (!skb)
  		goto errout;
  
  	err = inet_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
  					RTM_NEWNETCONF, 0, type);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet_netconf_msgsize_devconf() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout;
  	}
  	rtnl_notify(skb, net, 0, RTNLGRP_IPV4_NETCONF, NULL, GFP_KERNEL);
  	return;
  errout:
  	if (err < 0)
  		rtnl_set_sk_err(net, RTNLGRP_IPV4_NETCONF, err);
  }
  
  static const struct nla_policy devconf_ipv4_policy[NETCONFA_MAX+1] = {
  	[NETCONFA_IFINDEX]	= { .len = sizeof(int) },
  	[NETCONFA_FORWARDING]	= { .len = sizeof(int) },
  	[NETCONFA_RP_FILTER]	= { .len = sizeof(int) },
  	[NETCONFA_PROXY_NEIGH]	= { .len = sizeof(int) },
  	[NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN]	= { .len = sizeof(int) },
  };
  
  static int inet_netconf_get_devconf(struct sk_buff *in_skb,
  				    struct nlmsghdr *nlh)
  {
  	struct net *net = sock_net(in_skb->sk);
  	struct nlattr *tb[NETCONFA_MAX+1];
  	struct netconfmsg *ncm;
  	struct sk_buff *skb;
  	struct ipv4_devconf *devconf;
  	struct in_device *in_dev;
  	struct net_device *dev;
  	int ifindex;
  	int err;
  
  	err = nlmsg_parse(nlh, sizeof(*ncm), tb, NETCONFA_MAX,
  			  devconf_ipv4_policy);
  	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->ipv4.devconf_all;
  		break;
  	case NETCONFA_IFINDEX_DEFAULT:
  		devconf = net->ipv4.devconf_dflt;
  		break;
  	default:
  		dev = __dev_get_by_index(net, ifindex);
  		if (!dev)
  			goto errout;
  		in_dev = __in_dev_get_rtnl(dev);
  		if (!in_dev)
  			goto errout;
  		devconf = &in_dev->cnf;
  		break;
  	}
  
  	err = -ENOBUFS;
  	skb = nlmsg_new(inet_netconf_msgsize_devconf(NETCONFA_ALL), GFP_KERNEL);
  	if (!skb)
  		goto errout;
  
  	err = inet_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 inet_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 inet_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 in_device *in_dev;
  	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->ipv4.dev_addr_genid) ^
  			  net->dev_base_seq;
  		hlist_for_each_entry_rcu(dev, head, index_hlist) {
  			if (idx < s_idx)
  				goto cont;
  			in_dev = __in_dev_get_rcu(dev);
  			if (!in_dev)
  				goto cont;
  
  			if (inet_netconf_fill_devconf(skb, dev->ifindex,
  						      &in_dev->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 (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,
  					      net->ipv4.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 (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,
  					      net->ipv4.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 devinet_copy_dflt_conf(struct net *net, int i)
  {
  	struct net_device *dev;
  
  	rcu_read_lock();
  	for_each_netdev_rcu(net, dev) {
  		struct in_device *in_dev;
  
  		in_dev = __in_dev_get_rcu(dev);
  		if (in_dev && !test_bit(i, in_dev->cnf.state))
  			in_dev->cnf.data[i] = net->ipv4.devconf_dflt->data[i];
  	}
  	rcu_read_unlock();
  }
  
  /* called with RTNL locked */
  static void inet_forward_change(struct net *net)
  {
  	struct net_device *dev;
  	int on = IPV4_DEVCONF_ALL(net, FORWARDING);
  
  	IPV4_DEVCONF_ALL(net, ACCEPT_REDIRECTS) = !on;
  	IPV4_DEVCONF_DFLT(net, FORWARDING) = on;
  	inet_netconf_notify_devconf(net, NETCONFA_FORWARDING,
  				    NETCONFA_IFINDEX_ALL,
  				    net->ipv4.devconf_all);
  	inet_netconf_notify_devconf(net, NETCONFA_FORWARDING,
  				    NETCONFA_IFINDEX_DEFAULT,
  				    net->ipv4.devconf_dflt);
  
  	for_each_netdev(net, dev) {
  		struct in_device *in_dev;
  
  		if (on)
  			dev_disable_lro(dev);
  
  		in_dev = __in_dev_get_rtnl(dev);
  		if (in_dev) {
  			IN_DEV_CONF_SET(in_dev, FORWARDING, on);
  			inet_netconf_notify_devconf(net, NETCONFA_FORWARDING,
  						    dev->ifindex, &in_dev->cnf);
  		}
  	}
  }
  
  static int devinet_conf_ifindex(struct net *net, struct ipv4_devconf *cnf)
  {
  	if (cnf == net->ipv4.devconf_dflt)
  		return NETCONFA_IFINDEX_DEFAULT;
  	else if (cnf == net->ipv4.devconf_all)
  		return NETCONFA_IFINDEX_ALL;
  	else {
  		struct in_device *idev
  			= container_of(cnf, struct in_device, cnf);
  		return idev->dev->ifindex;
  	}
  }
  
  static int devinet_conf_proc(struct ctl_table *ctl, int write,
  			     void __user *buffer,
  			     size_t *lenp, loff_t *ppos)
  {
  	int old_value = *(int *)ctl->data;
  	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
  	int new_value = *(int *)ctl->data;
  
  	if (write) {
  		struct ipv4_devconf *cnf = ctl->extra1;
  		struct net *net = ctl->extra2;
  		int i = (int *)ctl->data - cnf->data;
  		int ifindex;
  
  		set_bit(i, cnf->state);
  
  		if (cnf == net->ipv4.devconf_dflt)
  			devinet_copy_dflt_conf(net, i);
  		if (i == IPV4_DEVCONF_ACCEPT_LOCAL - 1 ||
  		    i == IPV4_DEVCONF_ROUTE_LOCALNET - 1)
  			if ((new_value == 0) && (old_value != 0))
  				rt_cache_flush(net);
  
  		if (i == IPV4_DEVCONF_RP_FILTER - 1 &&
  		    new_value != old_value) {
  			ifindex = devinet_conf_ifindex(net, cnf);
  			inet_netconf_notify_devconf(net, NETCONFA_RP_FILTER,
  						    ifindex, cnf);
  		}
  		if (i == IPV4_DEVCONF_PROXY_ARP - 1 &&
  		    new_value != old_value) {
  			ifindex = devinet_conf_ifindex(net, cnf);
  			inet_netconf_notify_devconf(net, NETCONFA_PROXY_NEIGH,
  						    ifindex, cnf);
  		}
  		if (i == IPV4_DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN - 1 &&
  		    new_value != old_value) {
  			ifindex = devinet_conf_ifindex(net, cnf);
  			inet_netconf_notify_devconf(net, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
  						    ifindex, cnf);
  		}
  	}
  
  	return ret;
  }
  
  static int devinet_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;
  	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
  
  	if (write && *valp != val) {
  		struct net *net = ctl->extra2;
  
  		if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) {
  			if (!rtnl_trylock()) {
  				/* Restore the original values before restarting */
  				*valp = val;
  				*ppos = pos;
  				return restart_syscall();
  			}
  			if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) {
  				inet_forward_change(net);
  			} else {
  				struct ipv4_devconf *cnf = ctl->extra1;
  				struct in_device *idev =
  					container_of(cnf, struct in_device, cnf);
  				if (*valp)
  					dev_disable_lro(idev->dev);
  				inet_netconf_notify_devconf(net,
  							    NETCONFA_FORWARDING,
  							    idev->dev->ifindex,
  							    cnf);
  			}
  			rtnl_unlock();
  			rt_cache_flush(net);
  		} else
  			inet_netconf_notify_devconf(net, NETCONFA_FORWARDING,
  						    NETCONFA_IFINDEX_DEFAULT,
  						    net->ipv4.devconf_dflt);
  	}
  
  	return ret;
  }
  
  static int ipv4_doint_and_flush(struct ctl_table *ctl, int write,
  				void __user *buffer,
  				size_t *lenp, loff_t *ppos)
  {
  	int *valp = ctl->data;
  	int val = *valp;
  	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
  	struct net *net = ctl->extra2;
  
  	if (write && *valp != val)
  		rt_cache_flush(net);
  
  	return ret;
  }
  
  #define DEVINET_SYSCTL_ENTRY(attr, name, mval, proc) \
  	{ \
  		.procname	= name, \
  		.data		= ipv4_devconf.data + \
  				  IPV4_DEVCONF_ ## attr - 1, \
  		.maxlen		= sizeof(int), \
  		.mode		= mval, \
  		.proc_handler	= proc, \
  		.extra1		= &ipv4_devconf, \
  	}
  
  #define DEVINET_SYSCTL_RW_ENTRY(attr, name) \
  	DEVINET_SYSCTL_ENTRY(attr, name, 0644, devinet_conf_proc)
  
  #define DEVINET_SYSCTL_RO_ENTRY(attr, name) \
  	DEVINET_SYSCTL_ENTRY(attr, name, 0444, devinet_conf_proc)
  
  #define DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, proc) \
  	DEVINET_SYSCTL_ENTRY(attr, name, 0644, proc)
  
  #define DEVINET_SYSCTL_FLUSHING_ENTRY(attr, name) \
  	DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, ipv4_doint_and_flush)
  
  static struct devinet_sysctl_table {
  	struct ctl_table_header *sysctl_header;
  	struct ctl_table devinet_vars[__IPV4_DEVCONF_MAX];
  } devinet_sysctl = {
  	.devinet_vars = {
  		DEVINET_SYSCTL_COMPLEX_ENTRY(FORWARDING, "forwarding",
  					     devinet_sysctl_forward),
  		DEVINET_SYSCTL_RO_ENTRY(MC_FORWARDING, "mc_forwarding"),
  
  		DEVINET_SYSCTL_RW_ENTRY(ACCEPT_REDIRECTS, "accept_redirects"),
  		DEVINET_SYSCTL_RW_ENTRY(SECURE_REDIRECTS, "secure_redirects"),
  		DEVINET_SYSCTL_RW_ENTRY(SHARED_MEDIA, "shared_media"),
  		DEVINET_SYSCTL_RW_ENTRY(RP_FILTER, "rp_filter"),
  		DEVINET_SYSCTL_RW_ENTRY(SEND_REDIRECTS, "send_redirects"),
  		DEVINET_SYSCTL_RW_ENTRY(ACCEPT_SOURCE_ROUTE,
  					"accept_source_route"),
  		DEVINET_SYSCTL_RW_ENTRY(ACCEPT_LOCAL, "accept_local"),
  		DEVINET_SYSCTL_RW_ENTRY(SRC_VMARK, "src_valid_mark"),
  		DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP, "proxy_arp"),
  		DEVINET_SYSCTL_RW_ENTRY(MEDIUM_ID, "medium_id"),
  		DEVINET_SYSCTL_RW_ENTRY(BOOTP_RELAY, "bootp_relay"),
  		DEVINET_SYSCTL_RW_ENTRY(LOG_MARTIANS, "log_martians"),
  		DEVINET_SYSCTL_RW_ENTRY(TAG, "tag"),
  		DEVINET_SYSCTL_RW_ENTRY(ARPFILTER, "arp_filter"),
  		DEVINET_SYSCTL_RW_ENTRY(ARP_ANNOUNCE, "arp_announce"),
  		DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"),
  		DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"),
  		DEVINET_SYSCTL_RW_ENTRY(ARP_NOTIFY, "arp_notify"),
  		DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP_PVLAN, "proxy_arp_pvlan"),
  		DEVINET_SYSCTL_RW_ENTRY(FORCE_IGMP_VERSION,
  					"force_igmp_version"),
  		DEVINET_SYSCTL_RW_ENTRY(IGMPV2_UNSOLICITED_REPORT_INTERVAL,
  					"igmpv2_unsolicited_report_interval"),
  		DEVINET_SYSCTL_RW_ENTRY(IGMPV3_UNSOLICITED_REPORT_INTERVAL,
  					"igmpv3_unsolicited_report_interval"),
  		DEVINET_SYSCTL_RW_ENTRY(IGNORE_ROUTES_WITH_LINKDOWN,
  					"ignore_routes_with_linkdown"),
  		DEVINET_SYSCTL_RW_ENTRY(DROP_GRATUITOUS_ARP,
  					"drop_gratuitous_arp"),
  
  		DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"),
  		DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"),
  		DEVINET_SYSCTL_FLUSHING_ENTRY(PROMOTE_SECONDARIES,
  					      "promote_secondaries"),
  		DEVINET_SYSCTL_FLUSHING_ENTRY(ROUTE_LOCALNET,
  					      "route_localnet"),
  		DEVINET_SYSCTL_FLUSHING_ENTRY(DROP_UNICAST_IN_L2_MULTICAST,
  					      "drop_unicast_in_l2_multicast"),
  	},
  };
  
  static int __devinet_sysctl_register(struct net *net, char *dev_name,
  				     int ifindex, struct ipv4_devconf *p)
  {
  	int i;
  	struct devinet_sysctl_table *t;
  	char path[sizeof("net/ipv4/conf/") + IFNAMSIZ];
  
  	t = kmemdup(&devinet_sysctl, sizeof(*t), GFP_KERNEL);
  	if (!t)
  		goto out;
  
  	for (i = 0; i < ARRAY_SIZE(t->devinet_vars) - 1; i++) {
  		t->devinet_vars[i].data += (char *)p - (char *)&ipv4_devconf;
  		t->devinet_vars[i].extra1 = p;
  		t->devinet_vars[i].extra2 = net;
  	}
  
  	snprintf(path, sizeof(path), "net/ipv4/conf/%s", dev_name);
  
  	t->sysctl_header = register_net_sysctl(net, path, t->devinet_vars);
  	if (!t->sysctl_header)
  		goto free;
  
  	p->sysctl = t;
  
  	inet_netconf_notify_devconf(net, NETCONFA_ALL, ifindex, p);
  	return 0;
  
  free:
  	kfree(t);
  out:
  	return -ENOBUFS;
  }
  
  static void __devinet_sysctl_unregister(struct ipv4_devconf *cnf)
  {
  	struct devinet_sysctl_table *t = cnf->sysctl;
  
  	if (!t)
  		return;
  
  	cnf->sysctl = NULL;
  	unregister_net_sysctl_table(t->sysctl_header);
  	kfree(t);
  }
  
  static int devinet_sysctl_register(struct in_device *idev)
  {
  	int err;
  
  	if (!sysctl_dev_name_is_allowed(idev->dev->name))
  		return -EINVAL;
  
  	err = neigh_sysctl_register(idev->dev, idev->arp_parms, NULL);
  	if (err)
  		return err;
  	err = __devinet_sysctl_register(dev_net(idev->dev), idev->dev->name,
  					idev->dev->ifindex, &idev->cnf);
  	if (err)
  		neigh_sysctl_unregister(idev->arp_parms);
  	return err;
  }
  
  static void devinet_sysctl_unregister(struct in_device *idev)
  {
  	__devinet_sysctl_unregister(&idev->cnf);
  	neigh_sysctl_unregister(idev->arp_parms);
  }
  
  static struct ctl_table ctl_forward_entry[] = {
  	{
  		.procname	= "ip_forward",
  		.data		= &ipv4_devconf.data[
  					IPV4_DEVCONF_FORWARDING - 1],
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= devinet_sysctl_forward,
  		.extra1		= &ipv4_devconf,
  		.extra2		= &init_net,
  	},
  	{ },
  };
  #endif
  
  static __net_init int devinet_init_net(struct net *net)
  {
  	int err;
  	struct ipv4_devconf *all, *dflt;
  #ifdef CONFIG_SYSCTL
  	struct ctl_table *tbl = ctl_forward_entry;
  	struct ctl_table_header *forw_hdr;
  #endif
  
  	err = -ENOMEM;
  	all = &ipv4_devconf;
  	dflt = &ipv4_devconf_dflt;
  
  	if (!net_eq(net, &init_net)) {
  		all = kmemdup(all, sizeof(ipv4_devconf), GFP_KERNEL);
  		if (!all)
  			goto err_alloc_all;
  
  		dflt = kmemdup(dflt, sizeof(ipv4_devconf_dflt), GFP_KERNEL);
  		if (!dflt)
  			goto err_alloc_dflt;
  
  #ifdef CONFIG_SYSCTL
  		tbl = kmemdup(tbl, sizeof(ctl_forward_entry), GFP_KERNEL);
  		if (!tbl)
  			goto err_alloc_ctl;
  
  		tbl[0].data = &all->data[IPV4_DEVCONF_FORWARDING - 1];
  		tbl[0].extra1 = all;
  		tbl[0].extra2 = net;
  #endif
  	}
  
  #ifdef CONFIG_SYSCTL
  	err = __devinet_sysctl_register(net, "all", NETCONFA_IFINDEX_ALL, all);
  	if (err < 0)
  		goto err_reg_all;
  
  	err = __devinet_sysctl_register(net, "default",
  					NETCONFA_IFINDEX_DEFAULT, dflt);
  	if (err < 0)
  		goto err_reg_dflt;
  
  	err = -ENOMEM;
  	forw_hdr = register_net_sysctl(net, "net/ipv4", tbl);
  	if (!forw_hdr)
  		goto err_reg_ctl;
  	net->ipv4.forw_hdr = forw_hdr;
  #endif
  
  	net->ipv4.devconf_all = all;
  	net->ipv4.devconf_dflt = dflt;
  	return 0;
  
  #ifdef CONFIG_SYSCTL
  err_reg_ctl:
  	__devinet_sysctl_unregister(dflt);
  err_reg_dflt:
  	__devinet_sysctl_unregister(all);
  err_reg_all:
  	if (tbl != ctl_forward_entry)
  		kfree(tbl);
  err_alloc_ctl:
  #endif
  	if (dflt != &ipv4_devconf_dflt)
  		kfree(dflt);
  err_alloc_dflt:
  	if (all != &ipv4_devconf)
  		kfree(all);
  err_alloc_all:
  	return err;
  }
  
  static __net_exit void devinet_exit_net(struct net *net)
  {
  #ifdef CONFIG_SYSCTL
  	struct ctl_table *tbl;
  
  	tbl = net->ipv4.forw_hdr->ctl_table_arg;
  	unregister_net_sysctl_table(net->ipv4.forw_hdr);
  	__devinet_sysctl_unregister(net->ipv4.devconf_dflt);
  	__devinet_sysctl_unregister(net->ipv4.devconf_all);
  	kfree(tbl);
  #endif
  	kfree(net->ipv4.devconf_dflt);
  	kfree(net->ipv4.devconf_all);
  }
  
  static __net_initdata struct pernet_operations devinet_ops = {
  	.init = devinet_init_net,
  	.exit = devinet_exit_net,
  };
  
  static struct rtnl_af_ops inet_af_ops __read_mostly = {
  	.family		  = AF_INET,
  	.fill_link_af	  = inet_fill_link_af,
  	.get_link_af_size = inet_get_link_af_size,
  	.validate_link_af = inet_validate_link_af,
  	.set_link_af	  = inet_set_link_af,
  };
  
  void __init devinet_init(void)
  {
  	int i;
  
  	for (i = 0; i < IN4_ADDR_HSIZE; i++)
  		INIT_HLIST_HEAD(&inet_addr_lst[i]);
  
  	register_pernet_subsys(&devinet_ops);
  
  	register_gifconf(PF_INET, inet_gifconf);
  	register_netdevice_notifier(&ip_netdev_notifier);
  
  	queue_delayed_work(system_power_efficient_wq, &check_lifetime_work, 0);
  
  	rtnl_af_register(&inet_af_ops);
  
  	rtnl_register(PF_INET, RTM_NEWADDR, inet_rtm_newaddr, NULL, NULL);
  	rtnl_register(PF_INET, RTM_DELADDR, inet_rtm_deladdr, NULL, NULL);
  	rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr, NULL);
  	rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf,
  		      inet_netconf_dump_devconf, NULL);
  }
  