LXR linux/net/ipv4/datagram.c

   1/*
   2 *      common UDP/RAW code
   3 *      Linux INET implementation
   4 *
   5 * Authors:
   6 *      Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
   7 *
   8 *      This program is free software; you can redistribute it and/or
   9 *      modify it under the terms of the GNU General Public License
  10 *      as published by the Free Software Foundation; either version
  11 *      2 of the License, or (at your option) any later version.
  12 */
  13
  14#include <linux/types.h>
  15#include <linux/module.h>
  16#include <linux/ip.h>
  17#include <linux/in.h>
  18#include <net/ip.h>
  19#include <net/sock.h>
  20#include <net/route.h>
  21#include <net/tcp_states.h>
  22
  23int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
  24{
  25        struct inet_sock *inet = inet_sk(sk);
  26        struct sockaddr_in *usin = (struct sockaddr_in *) uaddr;
  27        struct flowi4 *fl4;
  28        struct rtable *rt;
  29        __be32 saddr;
  30        int oif;
  31        int err;
  32
  33
  34        if (addr_len < sizeof(*usin))
  35                return -EINVAL;
  36
  37        if (usin->sin_family != AF_INET)
  38                return -EAFNOSUPPORT;
  39
  40        sk_dst_reset(sk);
  41
  42        lock_sock(sk);
  43
  44        oif = sk->sk_bound_dev_if;
  45        saddr = inet->inet_saddr;
  46        if (ipv4_is_multicast(usin->sin_addr.s_addr)) {
  47                if (!oif)
  48                        oif = inet->mc_index;
  49                if (!saddr)
  50                        saddr = inet->mc_addr;
  51        }
  52        fl4 = &inet->cork.fl.u.ip4;
  53        rt = ip_route_connect(fl4, usin->sin_addr.s_addr, saddr,
  54                              RT_CONN_FLAGS(sk), oif,
  55                              sk->sk_protocol,
  56                              inet->inet_sport, usin->sin_port, sk, true);
  57        if (IS_ERR(rt)) {
  58                err = PTR_ERR(rt);
  59                if (err == -ENETUNREACH)
  60                        IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
  61                goto out;
  62        }
  63
  64        if ((rt->rt_flags & RTCF_BROADCAST) && !sock_flag(sk, SOCK_BROADCAST)) {
  65                ip_rt_put(rt);
  66                err = -EACCES;
  67                goto out;
  68        }
  69        if (!inet->inet_saddr)
  70                inet->inet_saddr = fl4->saddr;  /* Update source address */
  71        if (!inet->inet_rcv_saddr) {
  72                inet->inet_rcv_saddr = fl4->saddr;
  73                if (sk->sk_prot->rehash)
  74                        sk->sk_prot->rehash(sk);
  75        }
  76        inet->inet_daddr = fl4->daddr;
  77        inet->inet_dport = usin->sin_port;
  78        sk->sk_state = TCP_ESTABLISHED;
  79        inet->inet_id = jiffies;
  80
  81        sk_dst_set(sk, &rt->dst);
  82        err = 0;
  83out:
  84        release_sock(sk);
  85        return err;
  86}
  87EXPORT_SYMBOL(ip4_datagram_connect);
  88
  89void ip4_datagram_release_cb(struct sock *sk)
  90{
  91        const struct inet_sock *inet = inet_sk(sk);
  92        const struct ip_options_rcu *inet_opt;
  93        __be32 daddr = inet->inet_daddr;
  94        struct flowi4 fl4;
  95        struct rtable *rt;
  96
  97        if (! __sk_dst_get(sk) || __sk_dst_check(sk, 0))
  98                return;
  99
 100        rcu_read_lock();
 101        inet_opt = rcu_dereference(inet->inet_opt);
 102        if (inet_opt && inet_opt->opt.srr)
 103                daddr = inet_opt->opt.faddr;
 104        rt = ip_route_output_ports(sock_net(sk), &fl4, sk, daddr,
 105                                   inet->inet_saddr, inet->inet_dport,
 106                                   inet->inet_sport, sk->sk_protocol,
 107                                   RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
 108        if (!IS_ERR(rt))
 109                __sk_dst_set(sk, &rt->dst);
 110        rcu_read_unlock();
 111}
 112EXPORT_SYMBOL_GPL(ip4_datagram_release_cb);
 113