ipv6.c

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/* SCTP kernel 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 implementation
 *
 * SCTP over IPv6.
 *
 * This SCTP 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.
 *
 * This SCTP 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 <[email protected]>
 *
 * Or submit a bug report through the following website:
 *    http://www.sf.net/projects/lksctp
 *
 * Written or modified by:
 *    Le Yanqun         <[email protected]>
 *    Hui Huang         <[email protected]>
 *    La Monte H.P. Yarroll <[email protected]>
 *    Sridhar Samudrala     <[email protected]>
 *    Jon Grimm         <[email protected]>
 *    Ardelle Fan       <[email protected]>
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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/slab.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>

static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
                     union sctp_addr *s2);
static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
                  __be16 port);
static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
                const union sctp_addr *addr2);

/* 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;
    struct net *net = dev_net(ifa->idev->dev);
    int found = 0;

    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;
            addr->a.v6.sin6_addr = ifa->addr;
            addr->a.v6.sin6_scope_id = ifa->idev->dev->ifindex;
            addr->valid = 1;
            spin_lock_bh(&net->sctp.local_addr_lock);
            list_add_tail_rcu(&addr->list, &net->sctp.local_addr_list);
            sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_NEW);
            spin_unlock_bh(&net->sctp.local_addr_lock);
        }
        break;
    case NETDEV_DOWN:
        spin_lock_bh(&net->sctp.local_addr_lock);
        list_for_each_entry_safe(addr, temp,
                    &net->sctp.local_addr_list, list) {
            if (addr->a.sa.sa_family == AF_INET6 &&
                    ipv6_addr_equal(&addr->a.v6.sin6_addr,
                        &ifa->addr)) {
                sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_DEL);
                found = 1;
                addr->valid = 0;
                list_del_rcu(&addr->list);
                break;
            }
        }
        spin_unlock_bh(&net->sctp.local_addr_lock);
        if (found)
            kfree_rcu(addr, rcu);
        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,
                 u8 type, u8 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;
    struct net *net = dev_net(skb->dev);

    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(net, 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(net, 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;
    case NDISC_REDIRECT:
        sctp_icmp_redirect(sk, transport, skb);
        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)
{
    struct sock *sk = skb->sk;
    struct ipv6_pinfo *np = inet6_sk(sk);
    struct flowi6 fl6;

    memset(&fl6, 0, sizeof(fl6));

    fl6.flowi6_proto = sk->sk_protocol;

    /* Fill in the dest address from the route entry passed with the skb
     * and the source address from the transport.
     */
    fl6.daddr = transport->ipaddr.v6.sin6_addr;
    fl6.saddr = transport->saddr.v6.sin6_addr;

    fl6.flowlabel = np->flow_label;
    IP6_ECN_flow_xmit(sk, fl6.flowlabel);
    if (ipv6_addr_type(&fl6.saddr) & IPV6_ADDR_LINKLOCAL)
        fl6.flowi6_oif = transport->saddr.v6.sin6_scope_id;
    else
        fl6.flowi6_oif = sk->sk_bound_dev_if;

    if (np->opt && np->opt->srcrt) {
        struct rt0_hdr *rt0 = (struct rt0_hdr *) np->opt->srcrt;
        fl6.daddr = *rt0->addr;
    }

    SCTP_DEBUG_PRINTK("%s: skb:%p, len:%d, src:%pI6 dst:%pI6\n",
              __func__, skb, skb->len,
              &fl6.saddr, &fl6.daddr);

    SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);

    if (!(transport->param_flags & SPP_PMTUD_ENABLE))
        skb->local_df = 1;

    return ip6_xmit(sk, skb, &fl6, np->opt, np->tclass);
}

/* Returns the dst cache entry for the given source and destination ip
 * addresses.
 */
static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
                struct flowi *fl, struct sock *sk)
{
    struct sctp_association *asoc = t->asoc;
    struct dst_entry *dst = NULL;
    struct flowi6 *fl6 = &fl->u.ip6;
    struct sctp_bind_addr *bp;
    struct sctp_sockaddr_entry *laddr;
    union sctp_addr *baddr = NULL;
    union sctp_addr *daddr = &t->ipaddr;
    union sctp_addr dst_saddr;
    __u8 matchlen = 0;
    __u8 bmatchlen;
    sctp_scope_t scope;

    memset(fl6, 0, sizeof(struct flowi6));
    fl6->daddr = daddr->v6.sin6_addr;
    fl6->fl6_dport = daddr->v6.sin6_port;
    fl6->flowi6_proto = IPPROTO_SCTP;
    if (ipv6_addr_type(&daddr->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
        fl6->flowi6_oif = daddr->v6.sin6_scope_id;

    SCTP_DEBUG_PRINTK("%s: DST=%pI6 ", __func__, &fl6->daddr);

    if (asoc)
        fl6->fl6_sport = htons(asoc->base.bind_addr.port);

    if (saddr) {
        fl6->saddr = saddr->v6.sin6_addr;
        fl6->fl6_sport = saddr->v6.sin6_port;
        SCTP_DEBUG_PRINTK("SRC=%pI6 - ", &fl6->saddr);
    }

    dst = ip6_dst_lookup_flow(sk, fl6, NULL, false);
    if (!asoc || saddr)
        goto out;

    bp = &asoc->base.bind_addr;
    scope = sctp_scope(daddr);
    /* ip6_dst_lookup has filled in the fl6->saddr for us.  Check
     * to see if we can use it.
     */
    if (!IS_ERR(dst)) {
        /* Walk through the bind address list and look for a bind
         * address that matches the source address of the returned dst.
         */
        sctp_v6_to_addr(&dst_saddr, &fl6->saddr, htons(bp->port));
        rcu_read_lock();
        list_for_each_entry_rcu(laddr, &bp->address_list, list) {
            if (!laddr->valid || (laddr->state != SCTP_ADDR_SRC))
                continue;

            /* Do not compare against v4 addrs */
            if ((laddr->a.sa.sa_family == AF_INET6) &&
                (sctp_v6_cmp_addr(&dst_saddr, &laddr->a))) {
                rcu_read_unlock();
                goto out;
            }
        }
        rcu_read_unlock();
        /* None of the bound addresses match the source address of the
         * dst. So release it.
         */
        dst_release(dst);
        dst = NULL;
    }

    /* Walk through the bind address list and try to get the
     * best source address for a given destination.
     */
    rcu_read_lock();
    list_for_each_entry_rcu(laddr, &bp->address_list, list) {
        if (!laddr->valid && laddr->state != SCTP_ADDR_SRC)
            continue;
        if ((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;
            }
        }
    }
    rcu_read_unlock();
    if (baddr) {
        fl6->saddr = baddr->v6.sin6_addr;
        fl6->fl6_sport = baddr->v6.sin6_port;
        dst = ip6_dst_lookup_flow(sk, fl6, NULL, false);
    }

out:
    if (!IS_ERR(dst)) {
        struct rt6_info *rt;
        rt = (struct rt6_info *)dst;
        t->dst = dst;
        SCTP_DEBUG_PRINTK("rt6_dst:%pI6 rt6_src:%pI6\n",
            &rt->rt6i_dst.addr, &fl6->saddr);
    } else {
        t->dst = NULL;
        SCTP_DEBUG_PRINTK("NO ROUTE\n");
    }
}

/* 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)
{
    return ipv6_addr_diff(&s1->v6.sin6_addr, &s2->v6.sin6_addr);
}

/* 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_sock *sk,
                  struct sctp_transport *t,
                  struct flowi *fl)
{
    struct flowi6 *fl6 = &fl->u.ip6;
    union sctp_addr *saddr = &t->saddr;

    SCTP_DEBUG_PRINTK("%s: asoc:%p dst:%p\n", __func__, t->asoc, t->dst);

    if (t->dst) {
        saddr->v6.sin6_family = AF_INET6;
        saddr->v6.sin6_addr = fl6->saddr;
    }
}

/* 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);
    list_for_each_entry(ifp, &in6_dev->addr_list, if_list) {
        /* 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);
            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)
{
    __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;
        addr->v6.sin6_addr = ipv6_hdr(skb)->saddr;
    } else {
        *port = sh->dest;
        addr->v6.sin6_addr = ipv6_hdr(skb)->daddr;
    }
}

/* 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 */
    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);
    param->v6.addr = addr->v6.sin6_addr;

    return length;
}

/* Initialize a sctp_addr from struct in6_addr. */
static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
                  __be16 port)
{
    addr->sa.sa_family = AF_INET6;
    addr->v6.sin6_port = port;
    addr->v6.sin6_addr = *saddr;
}

/* 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;
    const struct in6_addr *in6 = (const 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(sock_net(&sp->inet.sk), 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 sock *newsk;
    struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
    struct sctp6_sock *newsctp6sk;

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

    sock_init_data(NULL, newsk);

    sctp_copy_sock(newsk, sk, asoc);
    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;

    newnp = inet6_sk(newsk);

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

    /* Initialize sk's sport, dport, rcv_saddr and daddr for getsockname()
     * and getpeername().
     */
    sctp_v6_to_sk_daddr(&asoc->peer.primary_addr, newsk);

    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, "%pI6 ", &addr->v6.sin6_addr);
}

static void sctp_v6_ecn_capable(struct sock *sk)
{
    inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
}

/* 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;
        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. */
        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)))
            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;
    struct sock *sk = sctp_opt2sk(opt);

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

    if (!af1 || !af2)
        return 0;

    /* If the socket is IPv6 only, v4 addrs will not match */
    if (__ipv6_only_sock(sk) && af1 != af2)
        return 0;

    /* Today, wildcard AF_INET/AF_INET6. */
    if (sctp_is_any(sk, addr1) || sctp_is_any(sk, 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) {
            struct net *net;
            if (!addr->v6.sin6_scope_id)
                return 0;
            net = sock_net(&opt->inet.sk);
            rcu_read_lock();
            dev = dev_get_by_index_rcu(net, addr->v6.sin6_scope_id);
            if (!dev ||
                !ipv6_chk_addr(net, &addr->v6.sin6_addr, dev, 0)) {
                rcu_read_unlock();
                return 0;
            }
            rcu_read_unlock();
        } else if (type == IPV6_ADDR_MAPPED) {
            if (!opt->v4mapped)
                return 0;
        }

        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;
            rcu_read_lock();
            dev = dev_get_by_index_rcu(sock_net(&opt->inet.sk),
                           addr->v6.sin6_scope_id);
            rcu_read_unlock();
            if (!dev)
                return 0;
        }
        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_IPV6_ADDRESS;
    if (!opt || !ipv6_only_sock(sctp_opt2sk(opt))) {
        types[1] = SCTP_PARAM_IPV4_ADDRESS;
        return 2;
    }
    return 1;
}

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,
    .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,
    .no_check      = 0,
    .flags         = SCTP_PROTOSW_FLAG,
};

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

static const 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_af_inet6 = {
    .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,
    .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,
    .ecn_capable       = sctp_v6_ecn_capable,
    .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 = {
    .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_af_inet6,
};

/* Initialize IPv6 support and register with socket layer.  */
void sctp_v6_pf_init(void)
{
    /* Register the SCTP specific PF_INET6 functions. */
    sctp_register_pf(&sctp_pf_inet6, PF_INET6);

    /* Register the SCTP specific AF_INET6 functions. */
    sctp_register_af(&sctp_af_inet6);
}

void sctp_v6_pf_exit(void)
{
    list_del(&sctp_af_inet6.list);
}

/* Initialize IPv6 support and register with socket layer.  */
int sctp_v6_protosw_init(void)
{
    int rc;

    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;
}

void sctp_v6_protosw_exit(void)
{
    inet6_unregister_protosw(&sctpv6_seqpacket_protosw);
    inet6_unregister_protosw(&sctpv6_stream_protosw);
    proto_unregister(&sctpv6_prot);
}


/* 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;
}

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