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
27struct 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->sk_uid;
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}
57EXPORT_SYMBOL(inet6_csk_route_req);
58
59void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
60{
61	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;
62
63	sin6->sin6_family = AF_INET6;
64	sin6->sin6_addr = sk->sk_v6_daddr;
65	sin6->sin6_port	= inet_sk(sk)->inet_dport;
66	/* We do not store received flowlabel for TCP */
67	sin6->sin6_flowinfo = 0;
68	sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
69						  sk->sk_bound_dev_if);
70}
71EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
72
73static inline
74struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
75{
76	return __sk_dst_check(sk, cookie);
77}
78
79static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
80						struct flowi6 *fl6)
81{
82	struct inet_sock *inet = inet_sk(sk);
83	struct ipv6_pinfo *np = inet6_sk(sk);
84	struct in6_addr *final_p, final;
85	struct dst_entry *dst;
86
87	memset(fl6, 0, sizeof(*fl6));
88	fl6->flowi6_proto = sk->sk_protocol;
89	fl6->daddr = sk->sk_v6_daddr;
90	fl6->saddr = np->saddr;
91	fl6->flowlabel = np->flow_label;
92	IP6_ECN_flow_xmit(sk, fl6->flowlabel);
93	fl6->flowi6_oif = sk->sk_bound_dev_if;
94	fl6->flowi6_mark = sk->sk_mark;
95	fl6->fl6_sport = inet->inet_sport;
96	fl6->fl6_dport = inet->inet_dport;
97	fl6->flowi6_uid = sk->sk_uid;
98	security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
99
100	rcu_read_lock();
101	final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
102	rcu_read_unlock();
103
104	dst = __inet6_csk_dst_check(sk, np->dst_cookie);
105	if (!dst) {
106		dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);
107
108		if (!IS_ERR(dst))
109			ip6_dst_store(sk, dst, NULL, NULL);
110	}
111	return dst;
112}
113
114int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused)
115{
116	struct ipv6_pinfo *np = inet6_sk(sk);
117	struct flowi6 fl6;
118	struct dst_entry *dst;
119	int res;
120
121	dst = inet6_csk_route_socket(sk, &fl6);
122	if (IS_ERR(dst)) {
123		WRITE_ONCE(sk->sk_err_soft, -PTR_ERR(dst));
124		sk->sk_route_caps = 0;
125		kfree_skb(skb);
126		return PTR_ERR(dst);
127	}
128
129	rcu_read_lock();
130	skb_dst_set_noref(skb, dst);
131
132	/* Restore final destination back after routing done */
133	fl6.daddr = sk->sk_v6_daddr;
134
135	res = ip6_xmit(sk, skb, &fl6, sk->sk_mark, rcu_dereference(np->opt),
136		       np->tclass,  sk->sk_priority);
137	rcu_read_unlock();
138	return res;
139}
140EXPORT_SYMBOL_GPL(inet6_csk_xmit);
141
142struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu)
143{
144	struct flowi6 fl6;
145	struct dst_entry *dst = inet6_csk_route_socket(sk, &fl6);
146
147	if (IS_ERR(dst))
148		return NULL;
149	dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
150
151	dst = inet6_csk_route_socket(sk, &fl6);
152	return IS_ERR(dst) ? NULL : dst;
153}
154EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);
155