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 } else if (!oif) { 46 oif = inet->uc_index; 47 } 48 fl4 = &inet->cork.fl.u.ip4; 49 rt = ip_route_connect(fl4, usin->sin_addr.s_addr, saddr, oif, 50 sk->sk_protocol, inet->inet_sport, 51 usin->sin_port, sk); 52 if (IS_ERR(rt)) { 53 err = PTR_ERR(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, 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(sk, true); 74 sk->sk_state = TCP_ESTABLISHED; 75 sk_set_txhash(sk); 76 inet->inet_id = get_random_u16(); 77 78 sk_dst_set(sk, &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(sock_net(sk), &fl4, sk, daddr, 120 inet->inet_saddr, inet->inet_dport, 121 inet->inet_sport, sk->sk_protocol, 122 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if); 123 124 dst = !IS_ERR(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