Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * common UDP/RAW code
4 * Linux INET implementation
5 *
6 * Authors:
7 * Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
8 */
9
10#include <linux/types.h>
11#include <linux/module.h>
12#include <linux/ip.h>
13#include <linux/in.h>
14#include <net/ip.h>
15#include <net/sock.h>
16#include <net/route.h>
17#include <net/tcp_states.h>
18
19int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
20{
21 struct inet_sock *inet = inet_sk(sk);
22 struct sockaddr_in *usin = (struct sockaddr_in *) uaddr;
23 struct flowi4 *fl4;
24 struct rtable *rt;
25 __be32 saddr;
26 int oif;
27 int err;
28
29
30 if (addr_len < sizeof(*usin))
31 return -EINVAL;
32
33 if (usin->sin_family != AF_INET)
34 return -EAFNOSUPPORT;
35
36 sk_dst_reset(sk);
37
38 oif = sk->sk_bound_dev_if;
39 saddr = inet->inet_saddr;
40 if (ipv4_is_multicast(usin->sin_addr.s_addr)) {
41 if (!oif || netif_index_is_l3_master(sock_net(sk), oif))
42 oif = inet->mc_index;
43 if (!saddr)
44 saddr = inet->mc_addr;
45 }
46 fl4 = &inet->cork.fl.u.ip4;
47 rt = ip_route_connect(fl4, usin->sin_addr.s_addr, saddr,
48 RT_CONN_FLAGS(sk), oif,
49 sk->sk_protocol,
50 inet->inet_sport, usin->sin_port, sk);
51 if (IS_ERR(rt)) {
52 err = PTR_ERR(rt);
53 if (err == -ENETUNREACH)
54 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
55 goto out;
56 }
57
58 if ((rt->rt_flags & RTCF_BROADCAST) && !sock_flag(sk, SOCK_BROADCAST)) {
59 ip_rt_put(rt);
60 err = -EACCES;
61 goto out;
62 }
63 if (!inet->inet_saddr)
64 inet->inet_saddr = fl4->saddr; /* Update source address */
65 if (!inet->inet_rcv_saddr) {
66 inet->inet_rcv_saddr = fl4->saddr;
67 if (sk->sk_prot->rehash)
68 sk->sk_prot->rehash(sk);
69 }
70 inet->inet_daddr = fl4->daddr;
71 inet->inet_dport = usin->sin_port;
72 sk->sk_state = TCP_ESTABLISHED;
73 sk_set_txhash(sk);
74 inet->inet_id = jiffies;
75
76 sk_dst_set(sk, &rt->dst);
77 err = 0;
78out:
79 return err;
80}
81EXPORT_SYMBOL(__ip4_datagram_connect);
82
83int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
84{
85 int res;
86
87 lock_sock(sk);
88 res = __ip4_datagram_connect(sk, uaddr, addr_len);
89 release_sock(sk);
90 return res;
91}
92EXPORT_SYMBOL(ip4_datagram_connect);
93
94/* Because UDP xmit path can manipulate sk_dst_cache without holding
95 * socket lock, we need to use sk_dst_set() here,
96 * even if we own the socket lock.
97 */
98void ip4_datagram_release_cb(struct sock *sk)
99{
100 const struct inet_sock *inet = inet_sk(sk);
101 const struct ip_options_rcu *inet_opt;
102 __be32 daddr = inet->inet_daddr;
103 struct dst_entry *dst;
104 struct flowi4 fl4;
105 struct rtable *rt;
106
107 rcu_read_lock();
108
109 dst = __sk_dst_get(sk);
110 if (!dst || !dst->obsolete || dst->ops->check(dst, 0)) {
111 rcu_read_unlock();
112 return;
113 }
114 inet_opt = rcu_dereference(inet->inet_opt);
115 if (inet_opt && inet_opt->opt.srr)
116 daddr = inet_opt->opt.faddr;
117 rt = ip_route_output_ports(sock_net(sk), &fl4, sk, daddr,
118 inet->inet_saddr, inet->inet_dport,
119 inet->inet_sport, sk->sk_protocol,
120 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
121
122 dst = !IS_ERR(rt) ? &rt->dst : NULL;
123 sk_dst_set(sk, dst);
124
125 rcu_read_unlock();
126}
127EXPORT_SYMBOL_GPL(ip4_datagram_release_cb);