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 | |
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(addr: usin->sin_addr.s_addr)) { |
41 | if (!oif || netif_index_is_l3_master(net: sock_net(sk), ifindex: oif)) |
42 | oif = READ_ONCE(inet->mc_index); |
43 | if (!saddr) |
44 | saddr = READ_ONCE(inet->mc_addr); |
45 | } else if (!oif) { |
46 | oif = READ_ONCE(inet->uc_index); |
47 | } |
48 | fl4 = &inet->cork.fl.u.ip4; |
49 | rt = ip_route_connect(fl4, dst: usin->sin_addr.s_addr, src: saddr, oif, |
50 | protocol: sk->sk_protocol, sport: inet->inet_sport, |
51 | dport: usin->sin_port, sk); |
52 | if (IS_ERR(ptr: rt)) { |
53 | err = PTR_ERR(ptr: rt); |
54 | if (err == -ENETUNREACH) |
55 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); |
56 | goto out; |
57 | } |
58 | |
59 | if ((rt->rt_flags & RTCF_BROADCAST) && !sock_flag(sk, flag: SOCK_BROADCAST)) { |
60 | ip_rt_put(rt); |
61 | err = -EACCES; |
62 | goto out; |
63 | } |
64 | if (!inet->inet_saddr) |
65 | inet->inet_saddr = fl4->saddr; /* Update source address */ |
66 | if (!inet->inet_rcv_saddr) { |
67 | inet->inet_rcv_saddr = fl4->saddr; |
68 | if (sk->sk_prot->rehash) |
69 | sk->sk_prot->rehash(sk); |
70 | } |
71 | inet->inet_daddr = fl4->daddr; |
72 | inet->inet_dport = usin->sin_port; |
73 | reuseport_has_conns_set(sk); |
74 | sk->sk_state = TCP_ESTABLISHED; |
75 | sk_set_txhash(sk); |
76 | atomic_set(v: &inet->inet_id, i: get_random_u16()); |
77 | |
78 | sk_dst_set(sk, dst: &rt->dst); |
79 | err = 0; |
80 | out: |
81 | return err; |
82 | } |
83 | EXPORT_SYMBOL(__ip4_datagram_connect); |
84 | |
85 | int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) |
86 | { |
87 | int res; |
88 | |
89 | lock_sock(sk); |
90 | res = __ip4_datagram_connect(sk, uaddr, addr_len); |
91 | release_sock(sk); |
92 | return res; |
93 | } |
94 | EXPORT_SYMBOL(ip4_datagram_connect); |
95 | |
96 | /* Because UDP xmit path can manipulate sk_dst_cache without holding |
97 | * socket lock, we need to use sk_dst_set() here, |
98 | * even if we own the socket lock. |
99 | */ |
100 | void ip4_datagram_release_cb(struct sock *sk) |
101 | { |
102 | const struct inet_sock *inet = inet_sk(sk); |
103 | const struct ip_options_rcu *inet_opt; |
104 | __be32 daddr = inet->inet_daddr; |
105 | struct dst_entry *dst; |
106 | struct flowi4 fl4; |
107 | struct rtable *rt; |
108 | |
109 | rcu_read_lock(); |
110 | |
111 | dst = __sk_dst_get(sk); |
112 | if (!dst || !dst->obsolete || dst->ops->check(dst, 0)) { |
113 | rcu_read_unlock(); |
114 | return; |
115 | } |
116 | inet_opt = rcu_dereference(inet->inet_opt); |
117 | if (inet_opt && inet_opt->opt.srr) |
118 | daddr = inet_opt->opt.faddr; |
119 | rt = ip_route_output_ports(net: sock_net(sk), fl4: &fl4, sk, daddr, |
120 | saddr: inet->inet_saddr, dport: inet->inet_dport, |
121 | sport: inet->inet_sport, proto: sk->sk_protocol, |
122 | RT_CONN_FLAGS(sk), oif: sk->sk_bound_dev_if); |
123 | |
124 | dst = !IS_ERR(ptr: rt) ? &rt->dst : NULL; |
125 | sk_dst_set(sk, dst); |
126 | |
127 | rcu_read_unlock(); |
128 | } |
129 | EXPORT_SYMBOL_GPL(ip4_datagram_release_cb); |
130 | |