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 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); 57 if (IS_ERR(rt)) { 58 err = PTR_ERR(rt); 59 if (err == -ENETUNREACH) 60 IP_INC_STATS(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_set_txhash(sk); 80 inet->inet_id = jiffies; 81 82 sk_dst_set(sk, &rt->dst); 83 err = 0; 84 out: 85 release_sock(sk); 86 return err; 87 } 88 EXPORT_SYMBOL(ip4_datagram_connect); 89 90 /* Because UDP xmit path can manipulate sk_dst_cache without holding 91 * socket lock, we need to use sk_dst_set() here, 92 * even if we own the socket lock. 93 */ 94 void ip4_datagram_release_cb(struct sock *sk) 95 { 96 const struct inet_sock *inet = inet_sk(sk); 97 const struct ip_options_rcu *inet_opt; 98 __be32 daddr = inet->inet_daddr; 99 struct dst_entry *dst; 100 struct flowi4 fl4; 101 struct rtable *rt; 102 103 rcu_read_lock(); 104 105 dst = __sk_dst_get(sk); 106 if (!dst || !dst->obsolete || dst->ops->check(dst, 0)) { 107 rcu_read_unlock(); 108 return; 109 } 110 inet_opt = rcu_dereference(inet->inet_opt); 111 if (inet_opt && inet_opt->opt.srr) 112 daddr = inet_opt->opt.faddr; 113 rt = ip_route_output_ports(sock_net(sk), &fl4, sk, daddr, 114 inet->inet_saddr, inet->inet_dport, 115 inet->inet_sport, sk->sk_protocol, 116 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if); 117 118 dst = !IS_ERR(rt) ? &rt->dst : NULL; 119 sk_dst_set(sk, dst); 120 121 rcu_read_unlock(); 122 } 123 EXPORT_SYMBOL_GPL(ip4_datagram_release_cb); 124