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ipv6.c

/* SCTP kernel reference Implementation
 * (C) Copyright IBM Corp. 2002, 2004
 * Copyright (c) 2001 Nokia, Inc.
 * Copyright (c) 2001 La Monte H.P. Yarroll
 * Copyright (c) 2002-2003 Intel Corp.
 *
 * This file is part of the SCTP kernel reference Implementation
 *
 * SCTP over IPv6.
 *
 * The SCTP reference implementation 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, or (at your option)
 * any later version.
 *
 * The SCTP reference implementation is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *             ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
 *
 * Or submit a bug report through the following website:
 *    http://www.sf.net/projects/lksctp
 *
 * Written or modified by:
 *    Le Yanqun             <yanqun.le@nokia.com>
 *    Hui Huang             <hui.huang@nokia.com>
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Sridhar Samudrala     <sri@us.ibm.com>
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *    Ardelle Fan     <ardelle.fan@intel.com>
 *
 * Based on:
 *    linux/net/ipv6/tcp_ipv6.c
 *
 * Any bugs reported given to us we will try to fix... any fixes shared will
 * be incorporated into the next SCTP release.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/init.h>
#include <linux/ipsec.h>

#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/random.h>
#include <linux/seq_file.h>

#include <net/protocol.h>
#include <net/ndisc.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/transp_v6.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/inet_common.h>
#include <net/inet_ecn.h>
#include <net/sctp/sctp.h>

#include <asm/uaccess.h>

/* Event handler for inet6 address addition/deletion events.
 * The sctp_local_addr_list needs to be protocted by a spin lock since
 * multiple notifiers (say IPv4 and IPv6) may be running at the same
 * time and thus corrupt the list.
 * The reader side is protected with RCU.
 */
static int sctp_inet6addr_event(struct notifier_block *this, unsigned long ev,
                        void *ptr)
{
      struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr;
      struct sctp_sockaddr_entry *addr = NULL;
      struct sctp_sockaddr_entry *temp;

      switch (ev) {
      case NETDEV_UP:
            addr = kmalloc(sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
            if (addr) {
                  addr->a.v6.sin6_family = AF_INET6;
                  addr->a.v6.sin6_port = 0;
                  memcpy(&addr->a.v6.sin6_addr, &ifa->addr,
                         sizeof(struct in6_addr));
                  addr->a.v6.sin6_scope_id = ifa->idev->dev->ifindex;
                  addr->valid = 1;
                  spin_lock_bh(&sctp_local_addr_lock);
                  list_add_tail_rcu(&addr->list, &sctp_local_addr_list);
                  spin_unlock_bh(&sctp_local_addr_lock);
            }
            break;
      case NETDEV_DOWN:
            spin_lock_bh(&sctp_local_addr_lock);
            list_for_each_entry_safe(addr, temp,
                              &sctp_local_addr_list, list) {
                  if (ipv6_addr_equal(&addr->a.v6.sin6_addr,
                                   &ifa->addr)) {
                        addr->valid = 0;
                        list_del_rcu(&addr->list);
                        break;
                  }
            }
            spin_unlock_bh(&sctp_local_addr_lock);
            if (addr && !addr->valid)
                  call_rcu(&addr->rcu, sctp_local_addr_free);
            break;
      }

      return NOTIFY_DONE;
}

static struct notifier_block sctp_inet6addr_notifier = {
      .notifier_call = sctp_inet6addr_event,
};

/* ICMP error handler. */
SCTP_STATIC void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                       int type, int code, int offset, __be32 info)
{
      struct inet6_dev *idev;
      struct sock *sk;
      struct sctp_association *asoc;
      struct sctp_transport *transport;
      struct ipv6_pinfo *np;
      sk_buff_data_t saveip, savesctp;
      int err;

      idev = in6_dev_get(skb->dev);

      /* Fix up skb to look at the embedded net header. */
      saveip       = skb->network_header;
      savesctp = skb->transport_header;
      skb_reset_network_header(skb);
      skb_set_transport_header(skb, offset);
      sk = sctp_err_lookup(AF_INET6, skb, sctp_hdr(skb), &asoc, &transport);
      /* Put back, the original pointers. */
      skb->network_header   = saveip;
      skb->transport_header = savesctp;
      if (!sk) {
            ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INERRORS);
            goto out;
      }

      /* Warning:  The sock lock is held.  Remember to call
       * sctp_err_finish!
       */

      switch (type) {
      case ICMPV6_PKT_TOOBIG:
            sctp_icmp_frag_needed(sk, asoc, transport, ntohl(info));
            goto out_unlock;
      case ICMPV6_PARAMPROB:
            if (ICMPV6_UNK_NEXTHDR == code) {
                  sctp_icmp_proto_unreachable(sk, asoc, transport);
                  goto out_unlock;
            }
            break;
      default:
            break;
      }

      np = inet6_sk(sk);
      icmpv6_err_convert(type, code, &err);
      if (!sock_owned_by_user(sk) && np->recverr) {
            sk->sk_err = err;
            sk->sk_error_report(sk);
      } else {  /* Only an error on timeout */
            sk->sk_err_soft = err;
      }

out_unlock:
      sctp_err_finish(sk, asoc);
out:
      if (likely(idev != NULL))
            in6_dev_put(idev);
}

/* Based on tcp_v6_xmit() in tcp_ipv6.c. */
static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport,
                  int ipfragok)
{
      struct sock *sk = skb->sk;
      struct ipv6_pinfo *np = inet6_sk(sk);
      struct flowi fl;

      memset(&fl, 0, sizeof(fl));

      fl.proto = sk->sk_protocol;

      /* Fill in the dest address from the route entry passed with the skb
       * and the source address from the transport.
       */
      ipv6_addr_copy(&fl.fl6_dst, &transport->ipaddr.v6.sin6_addr);
      ipv6_addr_copy(&fl.fl6_src, &transport->saddr.v6.sin6_addr);

      fl.fl6_flowlabel = np->flow_label;
      IP6_ECN_flow_xmit(sk, fl.fl6_flowlabel);
      if (ipv6_addr_type(&fl.fl6_src) & IPV6_ADDR_LINKLOCAL)
            fl.oif = transport->saddr.v6.sin6_scope_id;
      else
            fl.oif = sk->sk_bound_dev_if;

      if (np->opt && np->opt->srcrt) {
            struct rt0_hdr *rt0 = (struct rt0_hdr *) np->opt->srcrt;
            ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
      }

      SCTP_DEBUG_PRINTK("%s: skb:%p, len:%d, "
                    "src:" NIP6_FMT " dst:" NIP6_FMT "\n",
                    __FUNCTION__, skb, skb->len,
                    NIP6(fl.fl6_src), NIP6(fl.fl6_dst));

      SCTP_INC_STATS(SCTP_MIB_OUTSCTPPACKS);

      return ip6_xmit(sk, skb, &fl, np->opt, ipfragok);
}

/* Returns the dst cache entry for the given source and destination ip
 * addresses.
 */
static struct dst_entry *sctp_v6_get_dst(struct sctp_association *asoc,
                               union sctp_addr *daddr,
                               union sctp_addr *saddr)
{
      struct dst_entry *dst;
      struct flowi fl;

      memset(&fl, 0, sizeof(fl));
      ipv6_addr_copy(&fl.fl6_dst, &daddr->v6.sin6_addr);
      if (ipv6_addr_type(&daddr->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
            fl.oif = daddr->v6.sin6_scope_id;


      SCTP_DEBUG_PRINTK("%s: DST=" NIP6_FMT " ",
                    __FUNCTION__, NIP6(fl.fl6_dst));

      if (saddr) {
            ipv6_addr_copy(&fl.fl6_src, &saddr->v6.sin6_addr);
            SCTP_DEBUG_PRINTK(
                  "SRC=" NIP6_FMT " - ",
                  NIP6(fl.fl6_src));
      }

      dst = ip6_route_output(NULL, &fl);
      if (!dst->error) {
            struct rt6_info *rt;
            rt = (struct rt6_info *)dst;
            SCTP_DEBUG_PRINTK(
                  "rt6_dst:" NIP6_FMT " rt6_src:" NIP6_FMT "\n",
                  NIP6(rt->rt6i_dst.addr), NIP6(rt->rt6i_src.addr));
            return dst;
      }
      SCTP_DEBUG_PRINTK("NO ROUTE\n");
      dst_release(dst);
      return NULL;
}

/* Returns the number of consecutive initial bits that match in the 2 ipv6
 * addresses.
 */
static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
                               union sctp_addr *s2)
{
      struct in6_addr *a1 = &s1->v6.sin6_addr;
      struct in6_addr *a2 = &s2->v6.sin6_addr;
      int i, j;

      for (i = 0; i < 4 ; i++) {
            __be32 a1xora2;

            a1xora2 = a1->s6_addr32[i] ^ a2->s6_addr32[i];

            if ((j = fls(ntohl(a1xora2))))
                  return (i * 32 + 32 - j);
      }

      return (i*32);
}

/* Fills in the source address(saddr) based on the destination address(daddr)
 * and asoc's bind address list.
 */
static void sctp_v6_get_saddr(struct sctp_association *asoc,
                        struct dst_entry *dst,
                        union sctp_addr *daddr,
                        union sctp_addr *saddr)
{
      struct sctp_bind_addr *bp;
      struct sctp_sockaddr_entry *laddr;
      sctp_scope_t scope;
      union sctp_addr *baddr = NULL;
      __u8 matchlen = 0;
      __u8 bmatchlen;

      SCTP_DEBUG_PRINTK("%s: asoc:%p dst:%p "
                    "daddr:" NIP6_FMT " ",
                    __FUNCTION__, asoc, dst, NIP6(daddr->v6.sin6_addr));

      if (!asoc) {
            ipv6_get_saddr(dst, &daddr->v6.sin6_addr,&saddr->v6.sin6_addr);
            SCTP_DEBUG_PRINTK("saddr from ipv6_get_saddr: " NIP6_FMT "\n",
                          NIP6(saddr->v6.sin6_addr));
            return;
      }

      scope = sctp_scope(daddr);

      bp = &asoc->base.bind_addr;

      /* Go through the bind address list and find the best source address
       * that matches the scope of the destination address.
       */
      rcu_read_lock();
      list_for_each_entry_rcu(laddr, &bp->address_list, list) {
            if (!laddr->valid)
                  continue;
            if ((laddr->use_as_src) &&
                (laddr->a.sa.sa_family == AF_INET6) &&
                (scope <= sctp_scope(&laddr->a))) {
                  bmatchlen = sctp_v6_addr_match_len(daddr, &laddr->a);
                  if (!baddr || (matchlen < bmatchlen)) {
                        baddr = &laddr->a;
                        matchlen = bmatchlen;
                  }
            }
      }

      if (baddr) {
            memcpy(saddr, baddr, sizeof(union sctp_addr));
            SCTP_DEBUG_PRINTK("saddr: " NIP6_FMT "\n",
                          NIP6(saddr->v6.sin6_addr));
      } else {
            printk(KERN_ERR "%s: asoc:%p Could not find a valid source "
                   "address for the dest:" NIP6_FMT "\n",
                   __FUNCTION__, asoc, NIP6(daddr->v6.sin6_addr));
      }

      rcu_read_unlock();
}

/* Make a copy of all potential local addresses. */
static void sctp_v6_copy_addrlist(struct list_head *addrlist,
                          struct net_device *dev)
{
      struct inet6_dev *in6_dev;
      struct inet6_ifaddr *ifp;
      struct sctp_sockaddr_entry *addr;

      rcu_read_lock();
      if ((in6_dev = __in6_dev_get(dev)) == NULL) {
            rcu_read_unlock();
            return;
      }

      read_lock_bh(&in6_dev->lock);
      for (ifp = in6_dev->addr_list; ifp; ifp = ifp->if_next) {
            /* Add the address to the local list.  */
            addr = t_new(struct sctp_sockaddr_entry, GFP_ATOMIC);
            if (addr) {
                  addr->a.v6.sin6_family = AF_INET6;
                  addr->a.v6.sin6_port = 0;
                  addr->a.v6.sin6_addr = ifp->addr;
                  addr->a.v6.sin6_scope_id = dev->ifindex;
                  addr->valid = 1;
                  INIT_LIST_HEAD(&addr->list);
                  INIT_RCU_HEAD(&addr->rcu);
                  list_add_tail(&addr->list, addrlist);
            }
      }

      read_unlock_bh(&in6_dev->lock);
      rcu_read_unlock();
}

/* Initialize a sockaddr_storage from in incoming skb. */
static void sctp_v6_from_skb(union sctp_addr *addr,struct sk_buff *skb,
                       int is_saddr)
{
      void *from;
      __be16 *port;
      struct sctphdr *sh;

      port = &addr->v6.sin6_port;
      addr->v6.sin6_family = AF_INET6;
      addr->v6.sin6_flowinfo = 0; /* FIXME */
      addr->v6.sin6_scope_id = ((struct inet6_skb_parm *)skb->cb)->iif;

      sh = sctp_hdr(skb);
      if (is_saddr) {
            *port  = sh->source;
            from = &ipv6_hdr(skb)->saddr;
      } else {
            *port = sh->dest;
            from = &ipv6_hdr(skb)->daddr;
      }
      ipv6_addr_copy(&addr->v6.sin6_addr, from);
}

/* Initialize an sctp_addr from a socket. */
static void sctp_v6_from_sk(union sctp_addr *addr, struct sock *sk)
{
      addr->v6.sin6_family = AF_INET6;
      addr->v6.sin6_port = 0;
      addr->v6.sin6_addr = inet6_sk(sk)->rcv_saddr;
}

/* Initialize sk->sk_rcv_saddr from sctp_addr. */
static void sctp_v6_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
{
      if (addr->sa.sa_family == AF_INET && sctp_sk(sk)->v4mapped) {
            inet6_sk(sk)->rcv_saddr.s6_addr32[0] = 0;
            inet6_sk(sk)->rcv_saddr.s6_addr32[1] = 0;
            inet6_sk(sk)->rcv_saddr.s6_addr32[2] = htonl(0x0000ffff);
            inet6_sk(sk)->rcv_saddr.s6_addr32[3] =
                  addr->v4.sin_addr.s_addr;
      } else {
            inet6_sk(sk)->rcv_saddr = addr->v6.sin6_addr;
      }
}

/* Initialize sk->sk_daddr from sctp_addr. */
static void sctp_v6_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
{
      if (addr->sa.sa_family == AF_INET && sctp_sk(sk)->v4mapped) {
            inet6_sk(sk)->daddr.s6_addr32[0] = 0;
            inet6_sk(sk)->daddr.s6_addr32[1] = 0;
            inet6_sk(sk)->daddr.s6_addr32[2] = htonl(0x0000ffff);
            inet6_sk(sk)->daddr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
      } else {
            inet6_sk(sk)->daddr = addr->v6.sin6_addr;
      }
}

/* Initialize a sctp_addr from an address parameter. */
static void sctp_v6_from_addr_param(union sctp_addr *addr,
                            union sctp_addr_param *param,
                            __be16 port, int iif)
{
      addr->v6.sin6_family = AF_INET6;
      addr->v6.sin6_port = port;
      addr->v6.sin6_flowinfo = 0; /* BUG */
      ipv6_addr_copy(&addr->v6.sin6_addr, &param->v6.addr);
      addr->v6.sin6_scope_id = iif;
}

/* Initialize an address parameter from a sctp_addr and return the length
 * of the address parameter.
 */
static int sctp_v6_to_addr_param(const union sctp_addr *addr,
                         union sctp_addr_param *param)
{
      int length = sizeof(sctp_ipv6addr_param_t);

      param->v6.param_hdr.type = SCTP_PARAM_IPV6_ADDRESS;
      param->v6.param_hdr.length = htons(length);
      ipv6_addr_copy(&param->v6.addr, &addr->v6.sin6_addr);

      return length;
}

/* Initialize a sctp_addr from a dst_entry. */
static void sctp_v6_dst_saddr(union sctp_addr *addr, struct dst_entry *dst,
                        __be16 port)
{
      struct rt6_info *rt = (struct rt6_info *)dst;
      addr->sa.sa_family = AF_INET6;
      addr->v6.sin6_port = port;
      ipv6_addr_copy(&addr->v6.sin6_addr, &rt->rt6i_src.addr);
}

/* Compare addresses exactly.
 * v4-mapped-v6 is also in consideration.
 */
static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
                      const union sctp_addr *addr2)
{
      if (addr1->sa.sa_family != addr2->sa.sa_family) {
            if (addr1->sa.sa_family == AF_INET &&
                addr2->sa.sa_family == AF_INET6 &&
                ipv6_addr_v4mapped(&addr2->v6.sin6_addr)) {
                  if (addr2->v6.sin6_port == addr1->v4.sin_port &&
                      addr2->v6.sin6_addr.s6_addr32[3] ==
                      addr1->v4.sin_addr.s_addr)
                        return 1;
            }
            if (addr2->sa.sa_family == AF_INET &&
                addr1->sa.sa_family == AF_INET6 &&
                ipv6_addr_v4mapped(&addr1->v6.sin6_addr)) {
                  if (addr1->v6.sin6_port == addr2->v4.sin_port &&
                      addr1->v6.sin6_addr.s6_addr32[3] ==
                      addr2->v4.sin_addr.s_addr)
                        return 1;
            }
            return 0;
      }
      if (!ipv6_addr_equal(&addr1->v6.sin6_addr, &addr2->v6.sin6_addr))
            return 0;
      /* If this is a linklocal address, compare the scope_id. */
      if (ipv6_addr_type(&addr1->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) {
            if (addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
                (addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)) {
                  return 0;
            }
      }

      return 1;
}

/* Initialize addr struct to INADDR_ANY. */
static void sctp_v6_inaddr_any(union sctp_addr *addr, __be16 port)
{
      memset(addr, 0x00, sizeof(union sctp_addr));
      addr->v6.sin6_family = AF_INET6;
      addr->v6.sin6_port = port;
}

/* Is this a wildcard address? */
static int sctp_v6_is_any(const union sctp_addr *addr)
{
      return ipv6_addr_any(&addr->v6.sin6_addr);
}

/* Should this be available for binding?   */
static int sctp_v6_available(union sctp_addr *addr, struct sctp_sock *sp)
{
      int type;
      struct in6_addr *in6 = (struct in6_addr *)&addr->v6.sin6_addr;

      type = ipv6_addr_type(in6);
      if (IPV6_ADDR_ANY == type)
            return 1;
      if (type == IPV6_ADDR_MAPPED) {
            if (sp && !sp->v4mapped)
                  return 0;
            if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
                  return 0;
            sctp_v6_map_v4(addr);
            return sctp_get_af_specific(AF_INET)->available(addr, sp);
      }
      if (!(type & IPV6_ADDR_UNICAST))
            return 0;

      return ipv6_chk_addr(in6, NULL, 0);
}

/* This function checks if the address is a valid address to be used for
 * SCTP.
 *
 * Output:
 * Return 0 - If the address is a non-unicast or an illegal address.
 * Return 1 - If the address is a unicast.
 */
static int sctp_v6_addr_valid(union sctp_addr *addr,
                        struct sctp_sock *sp,
                        const struct sk_buff *skb)
{
      int ret = ipv6_addr_type(&addr->v6.sin6_addr);

      /* Support v4-mapped-v6 address. */
      if (ret == IPV6_ADDR_MAPPED) {
            /* Note: This routine is used in input, so v4-mapped-v6
             * are disallowed here when there is no sctp_sock.
             */
            if (!sp || !sp->v4mapped)
                  return 0;
            if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
                  return 0;
            sctp_v6_map_v4(addr);
            return sctp_get_af_specific(AF_INET)->addr_valid(addr, sp, skb);
      }

      /* Is this a non-unicast address */
      if (!(ret & IPV6_ADDR_UNICAST))
            return 0;

      return 1;
}

/* What is the scope of 'addr'?  */
static sctp_scope_t sctp_v6_scope(union sctp_addr *addr)
{
      int v6scope;
      sctp_scope_t retval;

      /* The IPv6 scope is really a set of bit fields.
       * See IFA_* in <net/if_inet6.h>.  Map to a generic SCTP scope.
       */

      v6scope = ipv6_addr_scope(&addr->v6.sin6_addr);
      switch (v6scope) {
      case IFA_HOST:
            retval = SCTP_SCOPE_LOOPBACK;
            break;
      case IFA_LINK:
            retval = SCTP_SCOPE_LINK;
            break;
      case IFA_SITE:
            retval = SCTP_SCOPE_PRIVATE;
            break;
      default:
            retval = SCTP_SCOPE_GLOBAL;
            break;
      }

      return retval;
}

/* Create and initialize a new sk for the socket to be returned by accept(). */
static struct sock *sctp_v6_create_accept_sk(struct sock *sk,
                                   struct sctp_association *asoc)
{
      struct inet_sock *inet = inet_sk(sk);
      struct sock *newsk;
      struct inet_sock *newinet;
      struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
      struct sctp6_sock *newsctp6sk;

      newsk = sk_alloc(sk->sk_net, PF_INET6, GFP_KERNEL, sk->sk_prot);
      if (!newsk)
            goto out;

      sock_init_data(NULL, newsk);

      newsk->sk_type = SOCK_STREAM;

      newsk->sk_prot = sk->sk_prot;
      newsk->sk_no_check = sk->sk_no_check;
      newsk->sk_reuse = sk->sk_reuse;

      newsk->sk_destruct = inet_sock_destruct;
      newsk->sk_family = PF_INET6;
      newsk->sk_protocol = IPPROTO_SCTP;
      newsk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
      newsk->sk_shutdown = sk->sk_shutdown;
      sock_reset_flag(sk, SOCK_ZAPPED);

      newsctp6sk = (struct sctp6_sock *)newsk;
      inet_sk(newsk)->pinet6 = &newsctp6sk->inet6;

      sctp_sk(newsk)->v4mapped = sctp_sk(sk)->v4mapped;

      newinet = inet_sk(newsk);
      newnp = inet6_sk(newsk);

      memcpy(newnp, np, sizeof(struct ipv6_pinfo));

      /* Initialize sk's sport, dport, rcv_saddr and daddr for getsockname()
       * and getpeername().
       */
      newinet->sport = inet->sport;
      newnp->saddr = np->saddr;
      newnp->rcv_saddr = np->rcv_saddr;
      newinet->dport = htons(asoc->peer.port);
      sctp_v6_to_sk_daddr(&asoc->peer.primary_addr, newsk);

      /* Init the ipv4 part of the socket since we can have sockets
       * using v6 API for ipv4.
       */
      newinet->uc_ttl = -1;
      newinet->mc_loop = 1;
      newinet->mc_ttl = 1;
      newinet->mc_index = 0;
      newinet->mc_list = NULL;

      if (ipv4_config.no_pmtu_disc)
            newinet->pmtudisc = IP_PMTUDISC_DONT;
      else
            newinet->pmtudisc = IP_PMTUDISC_WANT;

      sk_refcnt_debug_inc(newsk);

      if (newsk->sk_prot->init(newsk)) {
            sk_common_release(newsk);
            newsk = NULL;
      }

out:
      return newsk;
}

/* Map v4 address to mapped v6 address */
static void sctp_v6_addr_v4map(struct sctp_sock *sp, union sctp_addr *addr)
{
      if (sp->v4mapped && AF_INET == addr->sa.sa_family)
            sctp_v4_map_v6(addr);
}

/* Where did this skb come from?  */
static int sctp_v6_skb_iif(const struct sk_buff *skb)
{
      struct inet6_skb_parm *opt = (struct inet6_skb_parm *) skb->cb;
      return opt->iif;
}

/* Was this packet marked by Explicit Congestion Notification? */
static int sctp_v6_is_ce(const struct sk_buff *skb)
{
      return *((__u32 *)(ipv6_hdr(skb))) & htonl(1 << 20);
}

/* Dump the v6 addr to the seq file. */
static void sctp_v6_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
{
      seq_printf(seq, NIP6_FMT " ", NIP6(addr->v6.sin6_addr));
}

/* Initialize a PF_INET6 socket msg_name. */
static void sctp_inet6_msgname(char *msgname, int *addr_len)
{
      struct sockaddr_in6 *sin6;

      sin6 = (struct sockaddr_in6 *)msgname;
      sin6->sin6_family = AF_INET6;
      sin6->sin6_flowinfo = 0;
      sin6->sin6_scope_id = 0; /*FIXME */
      *addr_len = sizeof(struct sockaddr_in6);
}

/* Initialize a PF_INET msgname from a ulpevent. */
static void sctp_inet6_event_msgname(struct sctp_ulpevent *event,
                             char *msgname, int *addrlen)
{
      struct sockaddr_in6 *sin6, *sin6from;

      if (msgname) {
            union sctp_addr *addr;
            struct sctp_association *asoc;

            asoc = event->asoc;
            sctp_inet6_msgname(msgname, addrlen);
            sin6 = (struct sockaddr_in6 *)msgname;
            sin6->sin6_port = htons(asoc->peer.port);
            addr = &asoc->peer.primary_addr;

            /* Note: If we go to a common v6 format, this code
             * will change.
             */

            /* Map ipv4 address into v4-mapped-on-v6 address.  */
            if (sctp_sk(asoc->base.sk)->v4mapped &&
                AF_INET == addr->sa.sa_family) {
                  sctp_v4_map_v6((union sctp_addr *)sin6);
                  sin6->sin6_addr.s6_addr32[3] =
                        addr->v4.sin_addr.s_addr;
                  return;
            }

            sin6from = &asoc->peer.primary_addr.v6;
            ipv6_addr_copy(&sin6->sin6_addr, &sin6from->sin6_addr);
            if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
                  sin6->sin6_scope_id = sin6from->sin6_scope_id;
      }
}

/* Initialize a msg_name from an inbound skb. */
static void sctp_inet6_skb_msgname(struct sk_buff *skb, char *msgname,
                           int *addr_len)
{
      struct sctphdr *sh;
      struct sockaddr_in6 *sin6;

      if (msgname) {
            sctp_inet6_msgname(msgname, addr_len);
            sin6 = (struct sockaddr_in6 *)msgname;
            sh = sctp_hdr(skb);
            sin6->sin6_port = sh->source;

            /* Map ipv4 address into v4-mapped-on-v6 address. */
            if (sctp_sk(skb->sk)->v4mapped &&
                ip_hdr(skb)->version == 4) {
                  sctp_v4_map_v6((union sctp_addr *)sin6);
                  sin6->sin6_addr.s6_addr32[3] = ip_hdr(skb)->saddr;
                  return;
            }

            /* Otherwise, just copy the v6 address. */
            ipv6_addr_copy(&sin6->sin6_addr, &ipv6_hdr(skb)->saddr);
            if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL) {
                  struct sctp_ulpevent *ev = sctp_skb2event(skb);
                  sin6->sin6_scope_id = ev->iif;
            }
      }
}

/* Do we support this AF? */
static int sctp_inet6_af_supported(sa_family_t family, struct sctp_sock *sp)
{
      switch (family) {
      case AF_INET6:
            return 1;
      /* v4-mapped-v6 addresses */
      case AF_INET:
            if (!__ipv6_only_sock(sctp_opt2sk(sp)) && sp->v4mapped)
                  return 1;
      default:
            return 0;
      }
}

/* Address matching with wildcards allowed.  This extra level
 * of indirection lets us choose whether a PF_INET6 should
 * disallow any v4 addresses if we so choose.
 */
static int sctp_inet6_cmp_addr(const union sctp_addr *addr1,
                         const union sctp_addr *addr2,
                         struct sctp_sock *opt)
{
      struct sctp_af *af1, *af2;

      af1 = sctp_get_af_specific(addr1->sa.sa_family);
      af2 = sctp_get_af_specific(addr2->sa.sa_family);

      if (!af1 || !af2)
            return 0;
      /* Today, wildcard AF_INET/AF_INET6. */
      if (sctp_is_any(addr1) || sctp_is_any(addr2))
            return 1;

      if (addr1->sa.sa_family != addr2->sa.sa_family)
            return 0;

      return af1->cmp_addr(addr1, addr2);
}

/* Verify that the provided sockaddr looks bindable.   Common verification,
 * has already been taken care of.
 */
static int sctp_inet6_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
{
      struct sctp_af *af;

      /* ASSERT: address family has already been verified. */
      if (addr->sa.sa_family != AF_INET6)
            af = sctp_get_af_specific(addr->sa.sa_family);
      else {
            int type = ipv6_addr_type(&addr->v6.sin6_addr);
            struct net_device *dev;

            if (type & IPV6_ADDR_LINKLOCAL) {
                  if (!addr->v6.sin6_scope_id)
                        return 0;
                  dev = dev_get_by_index(&init_net, addr->v6.sin6_scope_id);
                  if (!dev)
                        return 0;
                  if (!ipv6_chk_addr(&addr->v6.sin6_addr, dev, 0)) {
                        dev_put(dev);
                        return 0;
                  }
                  dev_put(dev);
            }
            af = opt->pf->af;
      }
      return af->available(addr, opt);
}

/* Verify that the provided sockaddr looks sendable.   Common verification,
 * has already been taken care of.
 */
static int sctp_inet6_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
{
      struct sctp_af *af = NULL;

      /* ASSERT: address family has already been verified. */
      if (addr->sa.sa_family != AF_INET6)
            af = sctp_get_af_specific(addr->sa.sa_family);
      else {
            int type = ipv6_addr_type(&addr->v6.sin6_addr);
            struct net_device *dev;

            if (type & IPV6_ADDR_LINKLOCAL) {
                  if (!addr->v6.sin6_scope_id)
                        return 0;
                  dev = dev_get_by_index(&init_net, addr->v6.sin6_scope_id);
                  if (!dev)
                        return 0;
                  dev_put(dev);
            }
            af = opt->pf->af;
      }

      return af != NULL;
}

/* Fill in Supported Address Type information for INIT and INIT-ACK
 * chunks.   Note: In the future, we may want to look at sock options
 * to determine whether a PF_INET6 socket really wants to have IPV4
 * addresses.
 * Returns number of addresses supported.
 */
static int sctp_inet6_supported_addrs(const struct sctp_sock *opt,
                              __be16 *types)
{
      types[0] = SCTP_PARAM_IPV4_ADDRESS;
      types[1] = SCTP_PARAM_IPV6_ADDRESS;
      return 2;
}

static const struct proto_ops inet6_seqpacket_ops = {
      .family              = PF_INET6,
      .owner               = THIS_MODULE,
      .release       = inet6_release,
      .bind          = inet6_bind,
      .connect       = inet_dgram_connect,
      .socketpair    = sock_no_socketpair,
      .accept              = inet_accept,
      .getname       = inet6_getname,
      .poll          = sctp_poll,
      .ioctl               = inet6_ioctl,
      .listen              = sctp_inet_listen,
      .shutdown      = inet_shutdown,
      .setsockopt    = sock_common_setsockopt,
      .getsockopt    = sock_common_getsockopt,
      .sendmsg       = inet_sendmsg,
      .recvmsg       = sock_common_recvmsg,
      .mmap          = sock_no_mmap,
#ifdef CONFIG_COMPAT
      .compat_setsockopt = compat_sock_common_setsockopt,
      .compat_getsockopt = compat_sock_common_getsockopt,
#endif
};

static struct inet_protosw sctpv6_seqpacket_protosw = {
      .type          = SOCK_SEQPACKET,
      .protocol      = IPPROTO_SCTP,
      .prot              = &sctpv6_prot,
      .ops           = &inet6_seqpacket_ops,
      .capability    = -1,
      .no_check      = 0,
      .flags         = SCTP_PROTOSW_FLAG
};
static struct inet_protosw sctpv6_stream_protosw = {
      .type          = SOCK_STREAM,
      .protocol      = IPPROTO_SCTP,
      .prot              = &sctpv6_prot,
      .ops           = &inet6_seqpacket_ops,
      .capability    = -1,
      .no_check      = 0,
      .flags         = SCTP_PROTOSW_FLAG,
};

static int sctp6_rcv(struct sk_buff *skb)
{
      return sctp_rcv(skb) ? -1 : 0;
}

static struct inet6_protocol sctpv6_protocol = {
      .handler      = sctp6_rcv,
      .err_handler  = sctp_v6_err,
      .flags        = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
};

static struct sctp_af sctp_ipv6_specific = {
      .sa_family     = AF_INET6,
      .sctp_xmit     = sctp_v6_xmit,
      .setsockopt    = ipv6_setsockopt,
      .getsockopt    = ipv6_getsockopt,
      .get_dst       = sctp_v6_get_dst,
      .get_saddr     = sctp_v6_get_saddr,
      .copy_addrlist       = sctp_v6_copy_addrlist,
      .from_skb      = sctp_v6_from_skb,
      .from_sk       = sctp_v6_from_sk,
      .to_sk_saddr         = sctp_v6_to_sk_saddr,
      .to_sk_daddr         = sctp_v6_to_sk_daddr,
      .from_addr_param   = sctp_v6_from_addr_param,
      .to_addr_param       = sctp_v6_to_addr_param,
      .dst_saddr     = sctp_v6_dst_saddr,
      .cmp_addr      = sctp_v6_cmp_addr,
      .scope               = sctp_v6_scope,
      .addr_valid    = sctp_v6_addr_valid,
      .inaddr_any    = sctp_v6_inaddr_any,
      .is_any              = sctp_v6_is_any,
      .available     = sctp_v6_available,
      .skb_iif       = sctp_v6_skb_iif,
      .is_ce               = sctp_v6_is_ce,
      .seq_dump_addr       = sctp_v6_seq_dump_addr,
      .net_header_len      = sizeof(struct ipv6hdr),
      .sockaddr_len        = sizeof(struct sockaddr_in6),
#ifdef CONFIG_COMPAT
      .compat_setsockopt = compat_ipv6_setsockopt,
      .compat_getsockopt = compat_ipv6_getsockopt,
#endif
};

static struct sctp_pf sctp_pf_inet6_specific = {
      .event_msgname = sctp_inet6_event_msgname,
      .skb_msgname   = sctp_inet6_skb_msgname,
      .af_supported  = sctp_inet6_af_supported,
      .cmp_addr      = sctp_inet6_cmp_addr,
      .bind_verify   = sctp_inet6_bind_verify,
      .send_verify   = sctp_inet6_send_verify,
      .supported_addrs = sctp_inet6_supported_addrs,
      .create_accept_sk = sctp_v6_create_accept_sk,
      .addr_v4map    = sctp_v6_addr_v4map,
      .af            = &sctp_ipv6_specific,
};

/* Initialize IPv6 support and register with socket layer.  */
int sctp_v6_init(void)
{
      int rc;

      /* Register the SCTP specific PF_INET6 functions. */
      sctp_register_pf(&sctp_pf_inet6_specific, PF_INET6);

      /* Register the SCTP specific AF_INET6 functions. */
      sctp_register_af(&sctp_ipv6_specific);

      rc = proto_register(&sctpv6_prot, 1);
      if (rc)
            return rc;

      /* Add SCTPv6(UDP and TCP style) to inetsw6 linked list. */
      inet6_register_protosw(&sctpv6_seqpacket_protosw);
      inet6_register_protosw(&sctpv6_stream_protosw);

      return 0;
}

/* Register with inet6 layer. */
int sctp_v6_add_protocol(void)
{
      /* Register notifier for inet6 address additions/deletions. */
      register_inet6addr_notifier(&sctp_inet6addr_notifier);

      if (inet6_add_protocol(&sctpv6_protocol, IPPROTO_SCTP) < 0)
            return -EAGAIN;

      return 0;
}

/* IPv6 specific exit support. */
void sctp_v6_exit(void)
{
      inet6_unregister_protosw(&sctpv6_seqpacket_protosw);
      inet6_unregister_protosw(&sctpv6_stream_protosw);
      proto_unregister(&sctpv6_prot);
      list_del(&sctp_ipv6_specific.list);
}

/* Unregister with inet6 layer. */
void sctp_v6_del_protocol(void)
{
      inet6_del_protocol(&sctpv6_protocol, IPPROTO_SCTP);
      unregister_inet6addr_notifier(&sctp_inet6addr_notifier);
}

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