text: /*
   *	PF_INET6 socket protocol family
   *	Linux INET6 implementation
   *
   *	Authors:
   *	Pedro Roque		<roque@di.fc.ul.pt>
   *
   *	Adapted from linux/net/ipv4/af_inet.c
   *
   *	Fixes:
   *	piggy, Karl Knutson	:	Socket protocol table
   *	Hideaki YOSHIFUJI	:	sin6_scope_id support
   *	Arnaldo Melo		:	check proc_net_create return, cleanups
   *
   *	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.
   */
  
  #define pr_fmt(fmt) "IPv6: " fmt
  
  #include <linux/module.h>
  #include <linux/capability.h>
  #include <linux/errno.h>
  #include <linux/types.h>
  #include <linux/socket.h>
  #include <linux/in.h>
  #include <linux/kernel.h>
  #include <linux/timer.h>
  #include <linux/string.h>
  #include <linux/sockios.h>
  #include <linux/net.h>
  #include <linux/fcntl.h>
  #include <linux/mm.h>
  #include <linux/interrupt.h>
  #include <linux/proc_fs.h>
  #include <linux/stat.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  
  #include <linux/inet.h>
  #include <linux/netdevice.h>
  #include <linux/icmpv6.h>
  #include <linux/netfilter_ipv6.h>
  
  #include <net/ip.h>
  #include <net/ipv6.h>
  #include <net/udp.h>
  #include <net/udplite.h>
  #include <net/tcp.h>
  #include <net/ping.h>
  #include <net/protocol.h>
  #include <net/inet_common.h>
  #include <net/route.h>
  #include <net/transp_v6.h>
  #include <net/ip6_route.h>
  #include <net/addrconf.h>
  #include <net/ndisc.h>
  #ifdef CONFIG_IPV6_TUNNEL
  #include <net/ip6_tunnel.h>
  #endif
  
  #include <asm/uaccess.h>
  #include <linux/mroute6.h>
  
  MODULE_AUTHOR("Cast of dozens");
  MODULE_DESCRIPTION("IPv6 protocol stack for Linux");
  MODULE_LICENSE("GPL");
  
  /* The inetsw6 table contains everything that inet6_create needs to
   * build a new socket.
   */
  static struct list_head inetsw6[SOCK_MAX];
  static DEFINE_SPINLOCK(inetsw6_lock);
  
  struct ipv6_params ipv6_defaults = {
  	.disable_ipv6 = 0,
  	.autoconf = 1,
  };
  
  static int disable_ipv6_mod;
  
  module_param_named(disable, disable_ipv6_mod, int, 0444);
  MODULE_PARM_DESC(disable, "Disable IPv6 module such that it is non-functional");
  
  module_param_named(disable_ipv6, ipv6_defaults.disable_ipv6, int, 0444);
  MODULE_PARM_DESC(disable_ipv6, "Disable IPv6 on all interfaces");
  
  module_param_named(autoconf, ipv6_defaults.autoconf, int, 0444);
  MODULE_PARM_DESC(autoconf, "Enable IPv6 address autoconfiguration on all interfaces");
  
  static __inline__ struct ipv6_pinfo *inet6_sk_generic(struct sock *sk)
  {
  	const int offset = sk->sk_prot->obj_size - sizeof(struct ipv6_pinfo);
  
  	return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
  }
  
  static int inet6_create(struct net *net, struct socket *sock, int protocol,
  			int kern)
  {
  	struct inet_sock *inet;
  	struct ipv6_pinfo *np;
  	struct sock *sk;
  	struct inet_protosw *answer;
  	struct proto *answer_prot;
  	unsigned char answer_flags;
  	int try_loading_module = 0;
  	int err;
  
  	if (protocol < 0 || protocol >= IPPROTO_MAX)
  		return -EINVAL;
  
  	/* Look for the requested type/protocol pair. */
  lookup_protocol:
  	err = -ESOCKTNOSUPPORT;
  	rcu_read_lock();
  	list_for_each_entry_rcu(answer, &inetsw6[sock->type], list) {
  
  		err = 0;
  		/* Check the non-wild match. */
  		if (protocol == answer->protocol) {
  			if (protocol != IPPROTO_IP)
  				break;
  		} else {
  			/* Check for the two wild cases. */
  			if (IPPROTO_IP == protocol) {
  				protocol = answer->protocol;
  				break;
  			}
  			if (IPPROTO_IP == answer->protocol)
  				break;
  		}
  		err = -EPROTONOSUPPORT;
  	}
  
  	if (err) {
  		if (try_loading_module < 2) {
  			rcu_read_unlock();
  			/*
  			 * Be more specific, e.g. net-pf-10-proto-132-type-1
  			 * (net-pf-PF_INET6-proto-IPPROTO_SCTP-type-SOCK_STREAM)
  			 */
  			if (++try_loading_module == 1)
  				request_module("net-pf-%d-proto-%d-type-%d",
  						PF_INET6, protocol, sock->type);
  			/*
  			 * Fall back to generic, e.g. net-pf-10-proto-132
  			 * (net-pf-PF_INET6-proto-IPPROTO_SCTP)
  			 */
  			else
  				request_module("net-pf-%d-proto-%d",
  						PF_INET6, protocol);
  			goto lookup_protocol;
  		} else
  			goto out_rcu_unlock;
  	}
  
  	err = -EPERM;
  	if (sock->type == SOCK_RAW && !kern &&
  	    !ns_capable(net->user_ns, CAP_NET_RAW))
  		goto out_rcu_unlock;
  
  	sock->ops = answer->ops;
  	answer_prot = answer->prot;
  	answer_flags = answer->flags;
  	rcu_read_unlock();
  
  	WARN_ON(!answer_prot->slab);
  
  	err = -ENOBUFS;
  	sk = sk_alloc(net, PF_INET6, GFP_KERNEL, answer_prot, kern);
  	if (!sk)
  		goto out;
  
  	sock_init_data(sock, sk);
  
  	err = 0;
  	if (INET_PROTOSW_REUSE & answer_flags)
  		sk->sk_reuse = SK_CAN_REUSE;
  
  	inet = inet_sk(sk);
  	inet->is_icsk = (INET_PROTOSW_ICSK & answer_flags) != 0;
  
  	if (SOCK_RAW == sock->type) {
  		inet->inet_num = protocol;
  		if (IPPROTO_RAW == protocol)
  			inet->hdrincl = 1;
  	}
  
  	sk->sk_destruct		= inet_sock_destruct;
  	sk->sk_family		= PF_INET6;
  	sk->sk_protocol		= protocol;
  
  	sk->sk_backlog_rcv	= answer->prot->backlog_rcv;
  
  	inet_sk(sk)->pinet6 = np = inet6_sk_generic(sk);
  	np->hop_limit	= -1;
  	np->mcast_hops	= IPV6_DEFAULT_MCASTHOPS;
  	np->mc_loop	= 1;
  	np->pmtudisc	= IPV6_PMTUDISC_WANT;
  	sk->sk_ipv6only	= net->ipv6.sysctl.bindv6only;
  
  	/* Init the ipv4 part of the socket since we can have sockets
  	 * using v6 API for ipv4.
  	 */
  	inet->uc_ttl	= -1;
  
  	inet->mc_loop	= 1;
  	inet->mc_ttl	= 1;
  	inet->mc_index	= 0;
  	inet->mc_list	= NULL;
  	inet->rcv_tos	= 0;
  
  	if (net->ipv4.sysctl_ip_no_pmtu_disc)
  		inet->pmtudisc = IP_PMTUDISC_DONT;
  	else
  		inet->pmtudisc = IP_PMTUDISC_WANT;
  	/*
  	 * Increment only the relevant sk_prot->socks debug field, this changes
  	 * the previous behaviour of incrementing both the equivalent to
  	 * answer->prot->socks (inet6_sock_nr) and inet_sock_nr.
  	 *
  	 * This allows better debug granularity as we'll know exactly how many
  	 * UDPv6, TCPv6, etc socks were allocated, not the sum of all IPv6
  	 * transport protocol socks. -acme
  	 */
  	sk_refcnt_debug_inc(sk);
  
  	if (inet->inet_num) {
  		/* It assumes that any protocol which allows
  		 * the user to assign a number at socket
  		 * creation time automatically shares.
  		 */
  		inet->inet_sport = htons(inet->inet_num);
  		sk->sk_prot->hash(sk);
  	}
  	if (sk->sk_prot->init) {
  		err = sk->sk_prot->init(sk);
  		if (err) {
  			sk_common_release(sk);
  			goto out;
  		}
  	}
  out:
  	return err;
  out_rcu_unlock:
  	rcu_read_unlock();
  	goto out;
  }
  
  
  /* bind for INET6 API */
  int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
  {
  	struct sockaddr_in6 *addr = (struct sockaddr_in6 *)uaddr;
  	struct sock *sk = sock->sk;
  	struct inet_sock *inet = inet_sk(sk);
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct net *net = sock_net(sk);
  	__be32 v4addr = 0;
  	unsigned short snum;
  	int addr_type = 0;
  	int err = 0;
  
  	/* If the socket has its own bind function then use it. */
  	if (sk->sk_prot->bind)
  		return sk->sk_prot->bind(sk, uaddr, addr_len);
  
  	if (addr_len < SIN6_LEN_RFC2133)
  		return -EINVAL;
  
  	if (addr->sin6_family != AF_INET6)
  		return -EAFNOSUPPORT;
  
  	addr_type = ipv6_addr_type(&addr->sin6_addr);
  	if ((addr_type & IPV6_ADDR_MULTICAST) && sock->type == SOCK_STREAM)
  		return -EINVAL;
  
  	snum = ntohs(addr->sin6_port);
  	if (snum && snum < PROT_SOCK && !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
  		return -EACCES;
  
  	lock_sock(sk);
  
  	/* Check these errors (active socket, double bind). */
  	if (sk->sk_state != TCP_CLOSE || inet->inet_num) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	/* Check if the address belongs to the host. */
  	if (addr_type == IPV6_ADDR_MAPPED) {
  		int chk_addr_ret;
  
  		/* Binding to v4-mapped address on a v6-only socket
  		 * makes no sense
  		 */
  		if (sk->sk_ipv6only) {
  			err = -EINVAL;
  			goto out;
  		}
  
  		/* Reproduce AF_INET checks to make the bindings consistent */
  		v4addr = addr->sin6_addr.s6_addr32[3];
  		chk_addr_ret = inet_addr_type(net, v4addr);
  		if (!net->ipv4.sysctl_ip_nonlocal_bind &&
  		    !(inet->freebind || inet->transparent) &&
  		    v4addr != htonl(INADDR_ANY) &&
  		    chk_addr_ret != RTN_LOCAL &&
  		    chk_addr_ret != RTN_MULTICAST &&
  		    chk_addr_ret != RTN_BROADCAST) {
  			err = -EADDRNOTAVAIL;
  			goto out;
  		}
  	} else {
  		if (addr_type != IPV6_ADDR_ANY) {
  			struct net_device *dev = NULL;
  
  			rcu_read_lock();
  			if (__ipv6_addr_needs_scope_id(addr_type)) {
  				if (addr_len >= sizeof(struct sockaddr_in6) &&
  				    addr->sin6_scope_id) {
  					/* Override any existing binding, if another one
  					 * is supplied by user.
  					 */
  					sk->sk_bound_dev_if = addr->sin6_scope_id;
  				}
  
  				/* Binding to link-local address requires an interface */
  				if (!sk->sk_bound_dev_if) {
  					err = -EINVAL;
  					goto out_unlock;
  				}
  				dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
  				if (!dev) {
  					err = -ENODEV;
  					goto out_unlock;
  				}
  			}
  
  			/* ipv4 addr of the socket is invalid.  Only the
  			 * unspecified and mapped address have a v4 equivalent.
  			 */
  			v4addr = LOOPBACK4_IPV6;
  			if (!(addr_type & IPV6_ADDR_MULTICAST))	{
  				if (!(inet->freebind || inet->transparent) &&
  				    !ipv6_chk_addr(net, &addr->sin6_addr,
  						   dev, 0)) {
  					err = -EADDRNOTAVAIL;
  					goto out_unlock;
  				}
  			}
  			rcu_read_unlock();
  		}
  	}
  
  	inet->inet_rcv_saddr = v4addr;
  	inet->inet_saddr = v4addr;
  
  	sk->sk_v6_rcv_saddr = addr->sin6_addr;
  
  	if (!(addr_type & IPV6_ADDR_MULTICAST))
  		np->saddr = addr->sin6_addr;
  
  	/* Make sure we are allowed to bind here. */
  	if ((snum || !inet->bind_address_no_port) &&
  	    sk->sk_prot->get_port(sk, snum)) {
  		inet_reset_saddr(sk);
  		err = -EADDRINUSE;
  		goto out;
  	}
  
  	if (addr_type != IPV6_ADDR_ANY) {
  		sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
  		if (addr_type != IPV6_ADDR_MAPPED)
  			sk->sk_ipv6only = 1;
  	}
  	if (snum)
  		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
  	inet->inet_sport = htons(inet->inet_num);
  	inet->inet_dport = 0;
  	inet->inet_daddr = 0;
  out:
  	release_sock(sk);
  	return err;
  out_unlock:
  	rcu_read_unlock();
  	goto out;
  }
  EXPORT_SYMBOL(inet6_bind);
  
  int inet6_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;
  
  	if (!sk)
  		return -EINVAL;
  
  	/* Free mc lists */
  	ipv6_sock_mc_close(sk);
  
  	/* Free ac lists */
  	ipv6_sock_ac_close(sk);
  
  	return inet_release(sock);
  }
  EXPORT_SYMBOL(inet6_release);
  
  void inet6_destroy_sock(struct sock *sk)
  {
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct sk_buff *skb;
  	struct ipv6_txoptions *opt;
  
  	/* Release rx options */
  
  	skb = xchg(&np->pktoptions, NULL);
  	if (skb)
  		kfree_skb(skb);
  
  	skb = xchg(&np->rxpmtu, NULL);
  	if (skb)
  		kfree_skb(skb);
  
  	/* Free flowlabels */
  	fl6_free_socklist(sk);
  
  	/* Free tx options */
  
  	opt = xchg((__force struct ipv6_txoptions **)&np->opt, NULL);
  	if (opt) {
  		atomic_sub(opt->tot_len, &sk->sk_omem_alloc);
  		txopt_put(opt);
  	}
  }
  EXPORT_SYMBOL_GPL(inet6_destroy_sock);
  
  /*
   *	This does both peername and sockname.
   */
  
  int inet6_getname(struct socket *sock, struct sockaddr *uaddr,
  		 int *uaddr_len, int peer)
  {
  	struct sockaddr_in6 *sin = (struct sockaddr_in6 *)uaddr;
  	struct sock *sk = sock->sk;
  	struct inet_sock *inet = inet_sk(sk);
  	struct ipv6_pinfo *np = inet6_sk(sk);
  
  	sin->sin6_family = AF_INET6;
  	sin->sin6_flowinfo = 0;
  	sin->sin6_scope_id = 0;
  	if (peer) {
  		if (!inet->inet_dport)
  			return -ENOTCONN;
  		if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
  		    peer == 1)
  			return -ENOTCONN;
  		sin->sin6_port = inet->inet_dport;
  		sin->sin6_addr = sk->sk_v6_daddr;
  		if (np->sndflow)
  			sin->sin6_flowinfo = np->flow_label;
  	} else {
  		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
  			sin->sin6_addr = np->saddr;
  		else
  			sin->sin6_addr = sk->sk_v6_rcv_saddr;
  
  		sin->sin6_port = inet->inet_sport;
  	}
  	sin->sin6_scope_id = ipv6_iface_scope_id(&sin->sin6_addr,
  						 sk->sk_bound_dev_if);
  	*uaddr_len = sizeof(*sin);
  	return 0;
  }
  EXPORT_SYMBOL(inet6_getname);
  
  int inet6_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
  {
  	struct sock *sk = sock->sk;
  	struct net *net = sock_net(sk);
  
  	switch (cmd) {
  	case SIOCGSTAMP:
  		return sock_get_timestamp(sk, (struct timeval __user *)arg);
  
  	case SIOCGSTAMPNS:
  		return sock_get_timestampns(sk, (struct timespec __user *)arg);
  
  	case SIOCADDRT:
  	case SIOCDELRT:
  
  		return ipv6_route_ioctl(net, cmd, (void __user *)arg);
  
  	case SIOCSIFADDR:
  		return addrconf_add_ifaddr(net, (void __user *) arg);
  	case SIOCDIFADDR:
  		return addrconf_del_ifaddr(net, (void __user *) arg);
  	case SIOCSIFDSTADDR:
  		return addrconf_set_dstaddr(net, (void __user *) arg);
  	default:
  		if (!sk->sk_prot->ioctl)
  			return -ENOIOCTLCMD;
  		return sk->sk_prot->ioctl(sk, cmd, arg);
  	}
  	/*NOTREACHED*/
  	return 0;
  }
  EXPORT_SYMBOL(inet6_ioctl);
  
  const struct proto_ops inet6_stream_ops = {
  	.family		   = PF_INET6,
  	.owner		   = THIS_MODULE,
  	.release	   = inet6_release,
  	.bind		   = inet6_bind,
  	.connect	   = inet_stream_connect,	/* ok		*/
  	.socketpair	   = sock_no_socketpair,	/* a do nothing	*/
  	.accept		   = inet_accept,		/* ok		*/
  	.getname	   = inet6_getname,
  	.poll		   = tcp_poll,			/* ok		*/
  	.ioctl		   = inet6_ioctl,		/* must change  */
  	.listen		   = inet_listen,		/* ok		*/
  	.shutdown	   = inet_shutdown,		/* ok		*/
  	.setsockopt	   = sock_common_setsockopt,	/* ok		*/
  	.getsockopt	   = sock_common_getsockopt,	/* ok		*/
  	.sendmsg	   = inet_sendmsg,		/* ok		*/
  	.recvmsg	   = inet_recvmsg,		/* ok		*/
  	.mmap		   = sock_no_mmap,
  	.sendpage	   = inet_sendpage,
  	.splice_read	   = tcp_splice_read,
  #ifdef CONFIG_COMPAT
  	.compat_setsockopt = compat_sock_common_setsockopt,
  	.compat_getsockopt = compat_sock_common_getsockopt,
  #endif
  };
  
  const struct proto_ops inet6_dgram_ops = {
  	.family		   = PF_INET6,
  	.owner		   = THIS_MODULE,
  	.release	   = inet6_release,
  	.bind		   = inet6_bind,
  	.connect	   = inet_dgram_connect,	/* ok		*/
  	.socketpair	   = sock_no_socketpair,	/* a do nothing	*/
  	.accept		   = sock_no_accept,		/* a do nothing	*/
  	.getname	   = inet6_getname,
  	.poll		   = udp_poll,			/* ok		*/
  	.ioctl		   = inet6_ioctl,		/* must change  */
  	.listen		   = sock_no_listen,		/* ok		*/
  	.shutdown	   = inet_shutdown,		/* ok		*/
  	.setsockopt	   = sock_common_setsockopt,	/* ok		*/
  	.getsockopt	   = sock_common_getsockopt,	/* ok		*/
  	.sendmsg	   = inet_sendmsg,		/* ok		*/
  	.recvmsg	   = inet_recvmsg,		/* ok		*/
  	.mmap		   = sock_no_mmap,
  	.sendpage	   = sock_no_sendpage,
  #ifdef CONFIG_COMPAT
  	.compat_setsockopt = compat_sock_common_setsockopt,
  	.compat_getsockopt = compat_sock_common_getsockopt,
  #endif
  };
  
  static const struct net_proto_family inet6_family_ops = {
  	.family = PF_INET6,
  	.create = inet6_create,
  	.owner	= THIS_MODULE,
  };
  
  int inet6_register_protosw(struct inet_protosw *p)
  {
  	struct list_head *lh;
  	struct inet_protosw *answer;
  	struct list_head *last_perm;
  	int protocol = p->protocol;
  	int ret;
  
  	spin_lock_bh(&inetsw6_lock);
  
  	ret = -EINVAL;
  	if (p->type >= SOCK_MAX)
  		goto out_illegal;
  
  	/* If we are trying to override a permanent protocol, bail. */
  	answer = NULL;
  	ret = -EPERM;
  	last_perm = &inetsw6[p->type];
  	list_for_each(lh, &inetsw6[p->type]) {
  		answer = list_entry(lh, struct inet_protosw, list);
  
  		/* Check only the non-wild match. */
  		if (INET_PROTOSW_PERMANENT & answer->flags) {
  			if (protocol == answer->protocol)
  				break;
  			last_perm = lh;
  		}
  
  		answer = NULL;
  	}
  	if (answer)
  		goto out_permanent;
  
  	/* Add the new entry after the last permanent entry if any, so that
  	 * the new entry does not override a permanent entry when matched with
  	 * a wild-card protocol. But it is allowed to override any existing
  	 * non-permanent entry.  This means that when we remove this entry, the
  	 * system automatically returns to the old behavior.
  	 */
  	list_add_rcu(&p->list, last_perm);
  	ret = 0;
  out:
  	spin_unlock_bh(&inetsw6_lock);
  	return ret;
  
  out_permanent:
  	pr_err("Attempt to override permanent protocol %d\n", protocol);
  	goto out;
  
  out_illegal:
  	pr_err("Ignoring attempt to register invalid socket type %d\n",
  	       p->type);
  	goto out;
  }
  EXPORT_SYMBOL(inet6_register_protosw);
  
  void
  inet6_unregister_protosw(struct inet_protosw *p)
  {
  	if (INET_PROTOSW_PERMANENT & p->flags) {
  		pr_err("Attempt to unregister permanent protocol %d\n",
  		       p->protocol);
  	} else {
  		spin_lock_bh(&inetsw6_lock);
  		list_del_rcu(&p->list);
  		spin_unlock_bh(&inetsw6_lock);
  
  		synchronize_net();
  	}
  }
  EXPORT_SYMBOL(inet6_unregister_protosw);
  
  int inet6_sk_rebuild_header(struct sock *sk)
  {
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct dst_entry *dst;
  
  	dst = __sk_dst_check(sk, np->dst_cookie);
  
  	if (!dst) {
  		struct inet_sock *inet = inet_sk(sk);
  		struct in6_addr *final_p, final;
  		struct flowi6 fl6;
  
  		memset(&fl6, 0, sizeof(fl6));
  		fl6.flowi6_proto = sk->sk_protocol;
  		fl6.daddr = sk->sk_v6_daddr;
  		fl6.saddr = np->saddr;
  		fl6.flowlabel = np->flow_label;
  		fl6.flowi6_oif = sk->sk_bound_dev_if;
  		fl6.flowi6_mark = sk->sk_mark;
  		fl6.fl6_dport = inet->inet_dport;
  		fl6.fl6_sport = inet->inet_sport;
  		security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
  
  		rcu_read_lock();
  		final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt),
  					 &final);
  		rcu_read_unlock();
  
  		dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
  		if (IS_ERR(dst)) {
  			sk->sk_route_caps = 0;
  			sk->sk_err_soft = -PTR_ERR(dst);
  			return PTR_ERR(dst);
  		}
  
  		__ip6_dst_store(sk, dst, NULL, NULL);
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(inet6_sk_rebuild_header);
  
  bool ipv6_opt_accepted(const struct sock *sk, const struct sk_buff *skb,
  		       const struct inet6_skb_parm *opt)
  {
  	const struct ipv6_pinfo *np = inet6_sk(sk);
  
  	if (np->rxopt.all) {
  		if ((opt->hop && (np->rxopt.bits.hopopts ||
  				  np->rxopt.bits.ohopopts)) ||
  		    (ip6_flowinfo((struct ipv6hdr *) skb_network_header(skb)) &&
  		     np->rxopt.bits.rxflow) ||
  		    (opt->srcrt && (np->rxopt.bits.srcrt ||
  		     np->rxopt.bits.osrcrt)) ||
  		    ((opt->dst1 || opt->dst0) &&
  		     (np->rxopt.bits.dstopts || np->rxopt.bits.odstopts)))
  			return true;
  	}
  	return false;
  }
  EXPORT_SYMBOL_GPL(ipv6_opt_accepted);
  
  static struct packet_type ipv6_packet_type __read_mostly = {
  	.type = cpu_to_be16(ETH_P_IPV6),
  	.func = ipv6_rcv,
  };
  
  static int __init ipv6_packet_init(void)
  {
  	dev_add_pack(&ipv6_packet_type);
  	return 0;
  }
  
  static void ipv6_packet_cleanup(void)
  {
  	dev_remove_pack(&ipv6_packet_type);
  }
  
  static int __net_init ipv6_init_mibs(struct net *net)
  {
  	int i;
  
  	net->mib.udp_stats_in6 = alloc_percpu(struct udp_mib);
  	if (!net->mib.udp_stats_in6)
  		return -ENOMEM;
  	net->mib.udplite_stats_in6 = alloc_percpu(struct udp_mib);
  	if (!net->mib.udplite_stats_in6)
  		goto err_udplite_mib;
  	net->mib.ipv6_statistics = alloc_percpu(struct ipstats_mib);
  	if (!net->mib.ipv6_statistics)
  		goto err_ip_mib;
  
  	for_each_possible_cpu(i) {
  		struct ipstats_mib *af_inet6_stats;
  		af_inet6_stats = per_cpu_ptr(net->mib.ipv6_statistics, i);
  		u64_stats_init(&af_inet6_stats->syncp);
  	}
  
  
  	net->mib.icmpv6_statistics = alloc_percpu(struct icmpv6_mib);
  	if (!net->mib.icmpv6_statistics)
  		goto err_icmp_mib;
  	net->mib.icmpv6msg_statistics = kzalloc(sizeof(struct icmpv6msg_mib),
  						GFP_KERNEL);
  	if (!net->mib.icmpv6msg_statistics)
  		goto err_icmpmsg_mib;
  	return 0;
  
  err_icmpmsg_mib:
  	free_percpu(net->mib.icmpv6_statistics);
  err_icmp_mib:
  	free_percpu(net->mib.ipv6_statistics);
  err_ip_mib:
  	free_percpu(net->mib.udplite_stats_in6);
  err_udplite_mib:
  	free_percpu(net->mib.udp_stats_in6);
  	return -ENOMEM;
  }
  
  static void ipv6_cleanup_mibs(struct net *net)
  {
  	free_percpu(net->mib.udp_stats_in6);
  	free_percpu(net->mib.udplite_stats_in6);
  	free_percpu(net->mib.ipv6_statistics);
  	free_percpu(net->mib.icmpv6_statistics);
  	kfree(net->mib.icmpv6msg_statistics);
  }
  
  static int __net_init inet6_net_init(struct net *net)
  {
  	int err = 0;
  
  	net->ipv6.sysctl.bindv6only = 0;
  	net->ipv6.sysctl.icmpv6_time = 1*HZ;
  	net->ipv6.sysctl.flowlabel_consistency = 1;
  	net->ipv6.sysctl.auto_flowlabels = 0;
  	net->ipv6.sysctl.idgen_retries = 3;
  	net->ipv6.sysctl.idgen_delay = 1 * HZ;
  	net->ipv6.sysctl.flowlabel_state_ranges = 1;
  	atomic_set(&net->ipv6.fib6_sernum, 1);
  
  	err = ipv6_init_mibs(net);
  	if (err)
  		return err;
  #ifdef CONFIG_PROC_FS
  	err = udp6_proc_init(net);
  	if (err)
  		goto out;
  	err = tcp6_proc_init(net);
  	if (err)
  		goto proc_tcp6_fail;
  	err = ac6_proc_init(net);
  	if (err)
  		goto proc_ac6_fail;
  #endif
  	return err;
  
  #ifdef CONFIG_PROC_FS
  proc_ac6_fail:
  	tcp6_proc_exit(net);
  proc_tcp6_fail:
  	udp6_proc_exit(net);
  out:
  	ipv6_cleanup_mibs(net);
  	return err;
  #endif
  }
  
  static void __net_exit inet6_net_exit(struct net *net)
  {
  #ifdef CONFIG_PROC_FS
  	udp6_proc_exit(net);
  	tcp6_proc_exit(net);
  	ac6_proc_exit(net);
  #endif
  	ipv6_cleanup_mibs(net);
  }
  
  static struct pernet_operations inet6_net_ops = {
  	.init = inet6_net_init,
  	.exit = inet6_net_exit,
  };
  
  static const struct ipv6_stub ipv6_stub_impl = {
  	.ipv6_sock_mc_join = ipv6_sock_mc_join,
  	.ipv6_sock_mc_drop = ipv6_sock_mc_drop,
  	.ipv6_dst_lookup = ip6_dst_lookup,
  	.udpv6_encap_enable = udpv6_encap_enable,
  	.ndisc_send_na = ndisc_send_na,
  	.nd_tbl	= &nd_tbl,
  };
  
  static int __init inet6_init(void)
  {
  	struct list_head *r;
  	int err = 0;
  
  	sock_skb_cb_check_size(sizeof(struct inet6_skb_parm));
  
  	/* Register the socket-side information for inet6_create.  */
  	for (r = &inetsw6[0]; r < &inetsw6[SOCK_MAX]; ++r)
  		INIT_LIST_HEAD(r);
  
  	if (disable_ipv6_mod) {
  		pr_info("Loaded, but administratively disabled, reboot required to enable\n");
  		goto out;
  	}
  
  	err = proto_register(&tcpv6_prot, 1);
  	if (err)
  		goto out;
  
  	err = proto_register(&udpv6_prot, 1);
  	if (err)
  		goto out_unregister_tcp_proto;
  
  	err = proto_register(&udplitev6_prot, 1);
  	if (err)
  		goto out_unregister_udp_proto;
  
  	err = proto_register(&rawv6_prot, 1);
  	if (err)
  		goto out_unregister_udplite_proto;
  
  	err = proto_register(&pingv6_prot, 1);
  	if (err)
  		goto out_unregister_ping_proto;
  
  	/* We MUST register RAW sockets before we create the ICMP6,
  	 * IGMP6, or NDISC control sockets.
  	 */
  	err = rawv6_init();
  	if (err)
  		goto out_unregister_raw_proto;
  
  	/* Register the family here so that the init calls below will
  	 * be able to create sockets. (?? is this dangerous ??)
  	 */
  	err = sock_register(&inet6_family_ops);
  	if (err)
  		goto out_sock_register_fail;
  
  	/*
  	 *	ipngwg API draft makes clear that the correct semantics
  	 *	for TCP and UDP is to consider one TCP and UDP instance
  	 *	in a host available by both INET and INET6 APIs and
  	 *	able to communicate via both network protocols.
  	 */
  
  	err = register_pernet_subsys(&inet6_net_ops);
  	if (err)
  		goto register_pernet_fail;
  	err = icmpv6_init();
  	if (err)
  		goto icmp_fail;
  	err = ip6_mr_init();
  	if (err)
  		goto ipmr_fail;
  	err = ndisc_init();
  	if (err)
  		goto ndisc_fail;
  	err = igmp6_init();
  	if (err)
  		goto igmp_fail;
  
  	ipv6_stub = &ipv6_stub_impl;
  
  	err = ipv6_netfilter_init();
  	if (err)
  		goto netfilter_fail;
  	/* Create /proc/foo6 entries. */
  #ifdef CONFIG_PROC_FS
  	err = -ENOMEM;
  	if (raw6_proc_init())
  		goto proc_raw6_fail;
  	if (udplite6_proc_init())
  		goto proc_udplite6_fail;
  	if (ipv6_misc_proc_init())
  		goto proc_misc6_fail;
  	if (if6_proc_init())
  		goto proc_if6_fail;
  #endif
  	err = ip6_route_init();
  	if (err)
  		goto ip6_route_fail;
  	err = ndisc_late_init();
  	if (err)
  		goto ndisc_late_fail;
  	err = ip6_flowlabel_init();
  	if (err)
  		goto ip6_flowlabel_fail;
  	err = addrconf_init();
  	if (err)
  		goto addrconf_fail;
  
  	/* Init v6 extension headers. */
  	err = ipv6_exthdrs_init();
  	if (err)
  		goto ipv6_exthdrs_fail;
  
  	err = ipv6_frag_init();
  	if (err)
  		goto ipv6_frag_fail;
  
  	/* Init v6 transport protocols. */
  	err = udpv6_init();
  	if (err)
  		goto udpv6_fail;
  
  	err = udplitev6_init();
  	if (err)
  		goto udplitev6_fail;
  
  	err = tcpv6_init();
  	if (err)
  		goto tcpv6_fail;
  
  	err = ipv6_packet_init();
  	if (err)
  		goto ipv6_packet_fail;
  
  	err = pingv6_init();
  	if (err)
  		goto pingv6_fail;
  
  #ifdef CONFIG_SYSCTL
  	err = ipv6_sysctl_register();
  	if (err)
  		goto sysctl_fail;
  #endif
  out:
  	return err;
  
  #ifdef CONFIG_SYSCTL
  sysctl_fail:
  	pingv6_exit();
  #endif
  pingv6_fail:
  	ipv6_packet_cleanup();
  ipv6_packet_fail:
  	tcpv6_exit();
  tcpv6_fail:
  	udplitev6_exit();
  udplitev6_fail:
  	udpv6_exit();
  udpv6_fail:
  	ipv6_frag_exit();
  ipv6_frag_fail:
  	ipv6_exthdrs_exit();
  ipv6_exthdrs_fail:
  	addrconf_cleanup();
  addrconf_fail:
  	ip6_flowlabel_cleanup();
  ip6_flowlabel_fail:
  	ndisc_late_cleanup();
  ndisc_late_fail:
  	ip6_route_cleanup();
  ip6_route_fail:
  #ifdef CONFIG_PROC_FS
  	if6_proc_exit();
  proc_if6_fail:
  	ipv6_misc_proc_exit();
  proc_misc6_fail:
  	udplite6_proc_exit();
  proc_udplite6_fail:
  	raw6_proc_exit();
  proc_raw6_fail:
  #endif
  	ipv6_netfilter_fini();
  netfilter_fail:
  	igmp6_cleanup();
  igmp_fail:
  	ndisc_cleanup();
  ndisc_fail:
  	ip6_mr_cleanup();
  ipmr_fail:
  	icmpv6_cleanup();
  icmp_fail:
  	unregister_pernet_subsys(&inet6_net_ops);
  register_pernet_fail:
  	sock_unregister(PF_INET6);
  	rtnl_unregister_all(PF_INET6);
  out_sock_register_fail:
  	rawv6_exit();
  out_unregister_ping_proto:
  	proto_unregister(&pingv6_prot);
  out_unregister_raw_proto:
  	proto_unregister(&rawv6_prot);
  out_unregister_udplite_proto:
  	proto_unregister(&udplitev6_prot);
  out_unregister_udp_proto:
  	proto_unregister(&udpv6_prot);
  out_unregister_tcp_proto:
  	proto_unregister(&tcpv6_prot);
  	goto out;
  }
  module_init(inet6_init);
  
  MODULE_ALIAS_NETPROTO(PF_INET6);
  