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
inet6_csk_route_req(const struct sock * sk,struct dst_entry * dst,struct flowi6 * fl6,const struct request_sock * req,u8 proto)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
inet6_csk_route_socket(struct sock * sk,struct flowi6 * fl6)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
inet6_csk_xmit(struct sock * sk,struct sk_buff * skb,struct flowi * fl_unused)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
inet6_csk_update_pmtu(struct sock * sk,u32 mtu)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