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 if (!dst) { 52 dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p); 53 if (IS_ERR(dst)) 54 return NULL; 55 } 56 return dst; 57 } 58 59 static struct dst_entry *inet6_csk_route_socket(struct sock *sk, 60 struct flowi6 *fl6) 61 { 62 struct inet_sock *inet = inet_sk(sk); 63 struct ipv6_pinfo *np = inet6_sk(sk); 64 struct in6_addr *final_p; 65 struct dst_entry *dst; 66 67 memset(fl6, 0, sizeof(*fl6)); 68 fl6->flowi6_proto = sk->sk_protocol; 69 fl6->daddr = sk->sk_v6_daddr; 70 fl6->saddr = np->saddr; 71 fl6->flowlabel = np->flow_label; 72 IP6_ECN_flow_xmit(sk, fl6->flowlabel); 73 fl6->flowi6_oif = sk->sk_bound_dev_if; 74 fl6->flowi6_mark = sk->sk_mark; 75 fl6->fl6_sport = inet->inet_sport; 76 fl6->fl6_dport = inet->inet_dport; 77 fl6->flowi6_uid = sk_uid(sk); 78 security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6)); 79 80 rcu_read_lock(); 81 final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &np->final); 82 rcu_read_unlock(); 83 84 dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p); 85 86 if (!IS_ERR(dst)) 87 ip6_dst_store(sk, dst, false, false); 88 89 return dst; 90 } 91 92 int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused) 93 { 94 struct flowi6 *fl6 = &inet_sk(sk)->cork.fl.u.ip6; 95 struct ipv6_pinfo *np = inet6_sk(sk); 96 struct dst_entry *dst; 97 int res; 98 99 dst = __sk_dst_check(sk, np->dst_cookie); 100 if (unlikely(!dst)) { 101 dst = inet6_csk_route_socket(sk, fl6); 102 if (IS_ERR(dst)) { 103 WRITE_ONCE(sk->sk_err_soft, -PTR_ERR(dst)); 104 sk->sk_route_caps = 0; 105 kfree_skb(skb); 106 return PTR_ERR(dst); 107 } 108 /* Restore final destination back after routing done */ 109 fl6->daddr = sk->sk_v6_daddr; 110 } 111 112 rcu_read_lock(); 113 skb_dst_set_noref(skb, dst); 114 115 res = ip6_xmit(sk, skb, fl6, sk->sk_mark, rcu_dereference(np->opt), 116 np->tclass, READ_ONCE(sk->sk_priority)); 117 rcu_read_unlock(); 118 return res; 119 } 120 EXPORT_SYMBOL_GPL(inet6_csk_xmit); 121 122 struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu) 123 { 124 struct flowi6 *fl6 = &inet_sk(sk)->cork.fl.u.ip6; 125 struct dst_entry *dst; 126 127 dst = inet6_csk_route_socket(sk, fl6); 128 129 if (IS_ERR(dst)) 130 return NULL; 131 dst->ops->update_pmtu(dst, sk, NULL, mtu, true); 132 133 dst = inet6_csk_route_socket(sk, fl6); 134 return IS_ERR(dst) ? NULL : dst; 135 } 136