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 || netif_index_is_l3_master(sock_net(sk), 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