1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * Support for INET6 connection oriented protocols. 8 * 9 * Authors: See the TCPv6 sources 10 */ 11 12 #include <linux/module.h> 13 #include <linux/in6.h> 14 #include <linux/ipv6.h> 15 #include <linux/jhash.h> 16 #include <linux/slab.h> 17 18 #include <net/addrconf.h> 19 #include <net/inet_connection_sock.h> 20 #include <net/inet_ecn.h> 21 #include <net/inet_hashtables.h> 22 #include <net/ip6_route.h> 23 #include <net/sock.h> 24 #include <net/inet6_connection_sock.h> 25 #include <net/sock_reuseport.h> 26 27 struct dst_entry *inet6_csk_route_req(const struct sock *sk, 28 struct dst_entry *dst, 29 struct flowi6 *fl6, 30 const struct request_sock *req, 31 u8 proto) 32 { 33 const struct inet_request_sock *ireq = inet_rsk(req); 34 const struct ipv6_pinfo *np = inet6_sk(sk); 35 struct in6_addr *final_p, final; 36 37 memset(fl6, 0, sizeof(*fl6)); 38 fl6->flowi6_proto = proto; 39 fl6->daddr = ireq->ir_v6_rmt_addr; 40 rcu_read_lock(); 41 final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final); 42 rcu_read_unlock(); 43 fl6->saddr = ireq->ir_v6_loc_addr; 44 fl6->flowi6_oif = ireq->ir_iif; 45 fl6->flowi6_mark = ireq->ir_mark; 46 fl6->fl6_dport = ireq->ir_rmt_port; 47 fl6->fl6_sport = htons(ireq->ir_num); 48 fl6->flowi6_uid = sk_uid(sk); 49 security_req_classify_flow(req, flowi6_to_flowi_common(fl6)); 50 51 ip6_ecmp_set_mp_hash(sock_net(sk), fl6, tcp_rsk(req)->txhash); 52 53 if (!dst) { 54 dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p); 55 if (IS_ERR(dst)) 56 return NULL; 57 } 58 return dst; 59 } 60 61 struct dst_entry *inet6_csk_route_socket(struct sock *sk, 62 struct flowi6 *fl6) 63 { 64 struct inet_sock *inet = inet_sk(sk); 65 struct ipv6_pinfo *np = inet6_sk(sk); 66 struct in6_addr *final_p; 67 struct dst_entry *dst; 68 69 memset(fl6, 0, sizeof(*fl6)); 70 fl6->flowi6_proto = sk->sk_protocol; 71 fl6->daddr = sk->sk_v6_daddr; 72 fl6->saddr = np->saddr; 73 fl6->flowlabel = np->flow_label; 74 IP6_ECN_flow_xmit(sk, fl6->flowlabel); 75 76 if (sk->sk_protocol == IPPROTO_TCP) 77 ip6_ecmp_set_mp_hash(sock_net(sk), fl6, sk->sk_txhash); 78 fl6->flowi6_oif = sk->sk_bound_dev_if; 79 fl6->flowi6_mark = sk->sk_mark; 80 fl6->fl6_sport = inet->inet_sport; 81 fl6->fl6_dport = inet->inet_dport; 82 fl6->flowi6_uid = sk_uid(sk); 83 security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6)); 84 85 rcu_read_lock(); 86 final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &np->final); 87 rcu_read_unlock(); 88 89 dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p); 90 91 if (!IS_ERR(dst)) 92 ip6_dst_store(sk, dst, false, false); 93 94 return dst; 95 } 96 97 int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused) 98 { 99 struct flowi6 *fl6 = &inet_sk(sk)->cork.fl.u.ip6; 100 struct ipv6_pinfo *np = inet6_sk(sk); 101 struct dst_entry *dst; 102 int res; 103 104 dst = __sk_dst_check(sk, np->dst_cookie); 105 if (unlikely(!dst)) { 106 dst = inet6_csk_route_socket(sk, fl6); 107 if (IS_ERR(dst)) { 108 WRITE_ONCE(sk->sk_err_soft, -PTR_ERR(dst)); 109 sk->sk_route_caps = 0; 110 sk_skb_reason_drop(sk, skb, 111 SKB_DROP_REASON_IP_OUTNOROUTES); 112 return PTR_ERR(dst); 113 } 114 /* Restore final destination back after routing done */ 115 fl6->daddr = sk->sk_v6_daddr; 116 } 117 118 rcu_read_lock(); 119 skb_dst_set_noref(skb, dst); 120 121 res = ip6_xmit(sk, skb, fl6, sk->sk_mark, rcu_dereference(np->opt), 122 np->tclass, READ_ONCE(sk->sk_priority)); 123 rcu_read_unlock(); 124 return res; 125 } 126 EXPORT_SYMBOL_GPL(inet6_csk_xmit); 127