inet6_connection_sock.c

Go to the documentation of this file.

/*
 * INET        An implementation of the TCP/IP protocol suite for the LINUX
 *             operating system.  INET is implemented using the  BSD Socket
 *             interface as the means of communication with the user level.
 *
 *             Support for INET6 connection oriented protocols.
 *
 * Authors:    See the TCPv6 sources
 *
 *             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.
 */

#include <linux/module.h>
#include <linux/in6.h>
#include <linux/ipv6.h>
#include <linux/jhash.h>
#include <linux/slab.h>

#include <net/addrconf.h>
#include <net/inet_connection_sock.h>
#include <net/inet_ecn.h>
#include <net/inet_hashtables.h>
#include <net/ip6_route.h>
#include <net/sock.h>
#include <net/inet6_connection_sock.h>

int inet6_csk_bind_conflict(const struct sock *sk,
                const struct inet_bind_bucket *tb, bool relax)
{
    const struct sock *sk2;
    const struct hlist_node *node;

    /* We must walk the whole port owner list in this case. -DaveM */
    /*
     * See comment in inet_csk_bind_conflict about sock lookup
     * vs net namespaces issues.
     */
    sk_for_each_bound(sk2, node, &tb->owners) {
        if (sk != sk2 &&
            (!sk->sk_bound_dev_if ||
             !sk2->sk_bound_dev_if ||
             sk->sk_bound_dev_if == sk2->sk_bound_dev_if) &&
            (!sk->sk_reuse || !sk2->sk_reuse ||
             sk2->sk_state == TCP_LISTEN) &&
             ipv6_rcv_saddr_equal(sk, sk2))
            break;
    }

    return node != NULL;
}

EXPORT_SYMBOL_GPL(inet6_csk_bind_conflict);

struct dst_entry *inet6_csk_route_req(struct sock *sk,
                      struct flowi6 *fl6,
                      const struct request_sock *req)
{
    struct inet6_request_sock *treq = inet6_rsk(req);
    struct ipv6_pinfo *np = inet6_sk(sk);
    struct in6_addr *final_p, final;
    struct dst_entry *dst;

    memset(fl6, 0, sizeof(*fl6));
    fl6->flowi6_proto = IPPROTO_TCP;
    fl6->daddr = treq->rmt_addr;
    final_p = fl6_update_dst(fl6, np->opt, &final);
    fl6->saddr = treq->loc_addr;
    fl6->flowi6_oif = treq->iif;
    fl6->flowi6_mark = sk->sk_mark;
    fl6->fl6_dport = inet_rsk(req)->rmt_port;
    fl6->fl6_sport = inet_rsk(req)->loc_port;
    security_req_classify_flow(req, flowi6_to_flowi(fl6));

    dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);
    if (IS_ERR(dst))
        return NULL;

    return dst;
}

/*
 * request_sock (formerly open request) hash tables.
 */
static u32 inet6_synq_hash(const struct in6_addr *raddr, const __be16 rport,
               const u32 rnd, const u32 synq_hsize)
{
    u32 c;

    c = jhash_3words((__force u32)raddr->s6_addr32[0],
             (__force u32)raddr->s6_addr32[1],
             (__force u32)raddr->s6_addr32[2],
             rnd);

    c = jhash_2words((__force u32)raddr->s6_addr32[3],
             (__force u32)rport,
             c);

    return c & (synq_hsize - 1);
}

struct request_sock *inet6_csk_search_req(const struct sock *sk,
                      struct request_sock ***prevp,
                      const __be16 rport,
                      const struct in6_addr *raddr,
                      const struct in6_addr *laddr,
                      const int iif)
{
    const struct inet_connection_sock *icsk = inet_csk(sk);
    struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
    struct request_sock *req, **prev;

    for (prev = &lopt->syn_table[inet6_synq_hash(raddr, rport,
                             lopt->hash_rnd,
                             lopt->nr_table_entries)];
         (req = *prev) != NULL;
         prev = &req->dl_next) {
        const struct inet6_request_sock *treq = inet6_rsk(req);

        if (inet_rsk(req)->rmt_port == rport &&
            req->rsk_ops->family == AF_INET6 &&
            ipv6_addr_equal(&treq->rmt_addr, raddr) &&
            ipv6_addr_equal(&treq->loc_addr, laddr) &&
            (!treq->iif || treq->iif == iif)) {
            WARN_ON(req->sk != NULL);
            *prevp = prev;
            return req;
        }
    }

    return NULL;
}

EXPORT_SYMBOL_GPL(inet6_csk_search_req);

void inet6_csk_reqsk_queue_hash_add(struct sock *sk,
                    struct request_sock *req,
                    const unsigned long timeout)
{
    struct inet_connection_sock *icsk = inet_csk(sk);
    struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
    const u32 h = inet6_synq_hash(&inet6_rsk(req)->rmt_addr,
                      inet_rsk(req)->rmt_port,
                      lopt->hash_rnd, lopt->nr_table_entries);

    reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
    inet_csk_reqsk_queue_added(sk, timeout);
}

EXPORT_SYMBOL_GPL(inet6_csk_reqsk_queue_hash_add);

void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr)
{
    struct ipv6_pinfo *np = inet6_sk(sk);
    struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;

    sin6->sin6_family = AF_INET6;
    sin6->sin6_addr = np->daddr;
    sin6->sin6_port = inet_sk(sk)->inet_dport;
    /* We do not store received flowlabel for TCP */
    sin6->sin6_flowinfo = 0;
    sin6->sin6_scope_id = 0;
    if (sk->sk_bound_dev_if &&
        ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
        sin6->sin6_scope_id = sk->sk_bound_dev_if;
}

EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);

static inline
void __inet6_csk_dst_store(struct sock *sk, struct dst_entry *dst,
               const struct in6_addr *daddr,
               const struct in6_addr *saddr)
{
    __ip6_dst_store(sk, dst, daddr, saddr);
}

static inline
struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
{
    return __sk_dst_check(sk, cookie);
}

static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
                        struct flowi6 *fl6)
{
    struct inet_sock *inet = inet_sk(sk);
    struct ipv6_pinfo *np = inet6_sk(sk);
    struct in6_addr *final_p, final;
    struct dst_entry *dst;

    memset(fl6, 0, sizeof(*fl6));
    fl6->flowi6_proto = sk->sk_protocol;
    fl6->daddr = np->daddr;
    fl6->saddr = np->saddr;
    fl6->flowlabel = np->flow_label;
    IP6_ECN_flow_xmit(sk, fl6->flowlabel);
    fl6->flowi6_oif = sk->sk_bound_dev_if;
    fl6->flowi6_mark = sk->sk_mark;
    fl6->fl6_sport = inet->inet_sport;
    fl6->fl6_dport = inet->inet_dport;
    security_sk_classify_flow(sk, flowi6_to_flowi(fl6));

    final_p = fl6_update_dst(fl6, np->opt, &final);

    dst = __inet6_csk_dst_check(sk, np->dst_cookie);
    if (!dst) {
        dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);

        if (!IS_ERR(dst))
            __inet6_csk_dst_store(sk, dst, NULL, NULL);
    }
    return dst;
}

int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl_unused)
{
    struct sock *sk = skb->sk;
    struct ipv6_pinfo *np = inet6_sk(sk);
    struct flowi6 fl6;
    struct dst_entry *dst;
    int res;

    dst = inet6_csk_route_socket(sk, &fl6);
    if (IS_ERR(dst)) {
        sk->sk_err_soft = -PTR_ERR(dst);
        sk->sk_route_caps = 0;
        kfree_skb(skb);
        return PTR_ERR(dst);
    }

    rcu_read_lock();
    skb_dst_set_noref(skb, dst);

    /* Restore final destination back after routing done */
    fl6.daddr = np->daddr;

    res = ip6_xmit(sk, skb, &fl6, np->opt, np->tclass);
    rcu_read_unlock();
    return res;
}
EXPORT_SYMBOL_GPL(inet6_csk_xmit);

struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu)
{
    struct flowi6 fl6;
    struct dst_entry *dst = inet6_csk_route_socket(sk, &fl6);

    if (IS_ERR(dst))
        return NULL;
    dst->ops->update_pmtu(dst, sk, NULL, mtu);

    dst = inet6_csk_route_socket(sk, &fl6);
    return IS_ERR(dst) ? NULL : dst;
}
EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);