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
  23 int 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 rtable *rt;
  28         __be32 saddr;
  29         int oif;
  30         int err;
  31
  32
  33         if (addr_len < sizeof(*usin))
  34                 return -EINVAL;
  35
  36         if (usin->sin_family != AF_INET)
  37                 return -EAFNOSUPPORT;
  38
  39         sk_dst_reset(sk);
  40
  41         oif = sk->sk_bound_dev_if;
  42         saddr = inet->inet_saddr;
  43         if (ipv4_is_multicast(usin->sin_addr.s_addr)) {
  44                 if (!oif)
  45                         oif = inet->mc_index;
  46                 if (!saddr)
  47                         saddr = inet->mc_addr;
  48         }
  49         rt = ip_route_connect(usin->sin_addr.s_addr, saddr,
  50                               RT_CONN_FLAGS(sk), oif,
  51                               sk->sk_protocol,
  52                               inet->inet_sport, usin->sin_port, sk, true);
  53         if (IS_ERR(rt)) {
  54                 err = PTR_ERR(rt);
  55                 if (err == -ENETUNREACH)
  56                         IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
  57                 return err;
  58         }
  59
  60         if ((rt->rt_flags & RTCF_BROADCAST) && !sock_flag(sk, SOCK_BROADCAST)) {
  61                 ip_rt_put(rt);
  62                 return -EACCES;
  63         }
  64         if (!inet->inet_saddr)
  65                 inet->inet_saddr = rt->rt_src;  /* Update source address */
  66         if (!inet->inet_rcv_saddr) {
  67                 inet->inet_rcv_saddr = rt->rt_src;
  68                 if (sk->sk_prot->rehash)
  69                         sk->sk_prot->rehash(sk);
  70         }
  71         inet->inet_daddr = rt->rt_dst;
  72         inet->inet_dport = usin->sin_port;
  73         sk->sk_state = TCP_ESTABLISHED;
  74         inet->inet_id = jiffies;
  75
  76         sk_dst_set(sk, &rt->dst);
  77         return 0;
  78 }
  79 EXPORT_SYMBOL(ip4_datagram_connect);