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 flowi6 *fl6, 29 const struct request_sock *req, 30 u8 proto) 31 { 32 struct inet_request_sock *ireq = inet_rsk(req); 33 const struct ipv6_pinfo *np = inet6_sk(sk); 34 struct in6_addr *final_p, final; 35 struct dst_entry *dst; 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 dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p); 52 if (IS_ERR(dst)) 53 return NULL; 54 55 return dst; 56 } 57 58 static inline 59 struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie) 60 { 61 return __sk_dst_check(sk, cookie); 62 } 63 64 static struct dst_entry *inet6_csk_route_socket(struct sock *sk, 65 struct flowi6 *fl6) 66 { 67 struct inet_sock *inet = inet_sk(sk); 68 struct ipv6_pinfo *np = inet6_sk(sk); 69 struct in6_addr *final_p, final; 70 struct dst_entry *dst; 71 72 memset(fl6, 0, sizeof(*fl6)); 73 fl6->flowi6_proto = sk->sk_protocol; 74 fl6->daddr = sk->sk_v6_daddr; 75 fl6->saddr = np->saddr; 76 fl6->flowlabel = np->flow_label; 77 IP6_ECN_flow_xmit(sk, fl6->flowlabel); 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), &final); 87 rcu_read_unlock(); 88 89 dst = __inet6_csk_dst_check(sk, np->dst_cookie); 90 if (!dst) { 91 dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p); 92 93 if (!IS_ERR(dst)) 94 ip6_dst_store(sk, dst, NULL, NULL); 95 } 96 return dst; 97 } 98 99 int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused) 100 { 101 struct ipv6_pinfo *np = inet6_sk(sk); 102 struct flowi6 fl6; 103 struct dst_entry *dst; 104 int res; 105 106 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 kfree_skb(skb); 111 return PTR_ERR(dst); 112 } 113 114 rcu_read_lock(); 115 skb_dst_set_noref(skb, dst); 116 117 /* Restore final destination back after routing done */ 118 fl6.daddr = sk->sk_v6_daddr; 119 120 res = ip6_xmit(sk, skb, &fl6, sk->sk_mark, rcu_dereference(np->opt), 121 np->tclass, READ_ONCE(sk->sk_priority)); 122 rcu_read_unlock(); 123 return res; 124 } 125 EXPORT_SYMBOL_GPL(inet6_csk_xmit); 126 127 struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu) 128 { 129 struct flowi6 fl6; 130 struct dst_entry *dst = inet6_csk_route_socket(sk, &fl6); 131 132 if (IS_ERR(dst)) 133 return NULL; 134 dst->ops->update_pmtu(dst, sk, NULL, mtu, true); 135 136 dst = inet6_csk_route_socket(sk, &fl6); 137 return IS_ERR(dst) ? NULL : dst; 138 } 139