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        oif = sk->sk_bound_dev_if;
  43        saddr = inet->inet_saddr;
  44        if (ipv4_is_multicast(usin->sin_addr.s_addr)) {
  45                if (!oif)
  46                        oif = inet->mc_index;
  47                if (!saddr)
  48                        saddr = inet->mc_addr;
  49        }
  50        fl4 = &inet->cork.fl.u.ip4;
  51        rt = ip_route_connect(fl4, usin->sin_addr.s_addr, saddr,
  52                              RT_CONN_FLAGS(sk), oif,
  53                              sk->sk_protocol,
  54                              inet->inet_sport, usin->sin_port, sk);
  55        if (IS_ERR(rt)) {
  56                err = PTR_ERR(rt);
  57                if (err == -ENETUNREACH)
  58                        IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
  59                goto out;
  60        }
  61
  62        if ((rt->rt_flags & RTCF_BROADCAST) && !sock_flag(sk, SOCK_BROADCAST)) {
  63                ip_rt_put(rt);
  64                err = -EACCES;
  65                goto out;
  66        }
  67        if (!inet->inet_saddr)
  68                inet->inet_saddr = fl4->saddr;  /* Update source address */
  69        if (!inet->inet_rcv_saddr) {
  70                inet->inet_rcv_saddr = fl4->saddr;
  71                if (sk->sk_prot->rehash)
  72                        sk->sk_prot->rehash(sk);
  73        }
  74        inet->inet_daddr = fl4->daddr;
  75        inet->inet_dport = usin->sin_port;
  76        sk->sk_state = TCP_ESTABLISHED;
  77        sk_set_txhash(sk);
  78        inet->inet_id = jiffies;
  79
  80        sk_dst_set(sk, &rt->dst);
  81        err = 0;
  82out:
  83        return err;
  84}
  85EXPORT_SYMBOL(__ip4_datagram_connect);
  86
  87int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
  88{
  89        int res;
  90
  91        lock_sock(sk);
  92        res = __ip4_datagram_connect(sk, uaddr, addr_len);
  93        release_sock(sk);
  94        return res;
  95}
  96EXPORT_SYMBOL(ip4_datagram_connect);
  97
  98/* Because UDP xmit path can manipulate sk_dst_cache without holding
  99 * socket lock, we need to use sk_dst_set() here,
 100 * even if we own the socket lock.
 101 */
 102void ip4_datagram_release_cb(struct sock *sk)
 103{
 104        const struct inet_sock *inet = inet_sk(sk);
 105        const struct ip_options_rcu *inet_opt;
 106        __be32 daddr = inet->inet_daddr;
 107        struct dst_entry *dst;
 108        struct flowi4 fl4;
 109        struct rtable *rt;
 110
 111        rcu_read_lock();
 112
 113        dst = __sk_dst_get(sk);
 114        if (!dst || !dst->obsolete || dst->ops->check(dst, 0)) {
 115                rcu_read_unlock();
 116                return;
 117        }
 118        inet_opt = rcu_dereference(inet->inet_opt);
 119        if (inet_opt && inet_opt->opt.srr)
 120                daddr = inet_opt->opt.faddr;
 121        rt = ip_route_output_ports(sock_net(sk), &fl4, sk, daddr,
 122                                   inet->inet_saddr, inet->inet_dport,
 123                                   inet->inet_sport, sk->sk_protocol,
 124                                   RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
 125
 126        dst = !IS_ERR(rt) ? &rt->dst : NULL;
 127        sk_dst_set(sk, dst);
 128
 129        rcu_read_unlock();
 130}
 131EXPORT_SYMBOL_GPL(ip4_datagram_release_cb);
 132