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/in.h>
13 #include <net/ip.h>
14 #include <net/sock.h>
15 #include <net/route.h>
16 #include <net/tcp_states.h>
17 #include <net/sock_reuseport.h>
18
__ip4_datagram_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)19 int __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 reuseport_has_conns(sk, true);
73 sk->sk_state = TCP_ESTABLISHED;
74 sk_set_txhash(sk);
75 inet->inet_id = prandom_u32();
76
77 sk_dst_set(sk, &rt->dst);
78 err = 0;
79 out:
80 return err;
81 }
82 EXPORT_SYMBOL(__ip4_datagram_connect);
83
ip4_datagram_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)84 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
85 {
86 int res;
87
88 lock_sock(sk);
89 res = __ip4_datagram_connect(sk, uaddr, addr_len);
90 release_sock(sk);
91 return res;
92 }
93 EXPORT_SYMBOL(ip4_datagram_connect);
94
95 /* Because UDP xmit path can manipulate sk_dst_cache without holding
96 * socket lock, we need to use sk_dst_set() here,
97 * even if we own the socket lock.
98 */
ip4_datagram_release_cb(struct sock * sk)99 void ip4_datagram_release_cb(struct sock *sk)
100 {
101 const struct inet_sock *inet = inet_sk(sk);
102 const struct ip_options_rcu *inet_opt;
103 __be32 daddr = inet->inet_daddr;
104 struct dst_entry *dst;
105 struct flowi4 fl4;
106 struct rtable *rt;
107
108 rcu_read_lock();
109
110 dst = __sk_dst_get(sk);
111 if (!dst || !dst->obsolete || dst->ops->check(dst, 0)) {
112 rcu_read_unlock();
113 return;
114 }
115 inet_opt = rcu_dereference(inet->inet_opt);
116 if (inet_opt && inet_opt->opt.srr)
117 daddr = inet_opt->opt.faddr;
118 rt = ip_route_output_ports(sock_net(sk), &fl4, sk, daddr,
119 inet->inet_saddr, inet->inet_dport,
120 inet->inet_sport, sk->sk_protocol,
121 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
122
123 dst = !IS_ERR(rt) ? &rt->dst : NULL;
124 sk_dst_set(sk, dst);
125
126 rcu_read_unlock();
127 }
128 EXPORT_SYMBOL_GPL(ip4_datagram_release_cb);
129