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(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 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 */ 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