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 flowi6 * fl6,const struct request_sock * req,u8 proto)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->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 }
57 EXPORT_SYMBOL(inet6_csk_route_req);
58 
inet6_csk_addr2sockaddr(struct sock * sk,struct sockaddr * uaddr)59 void 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 }
71 EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
72 
73 static inline
__inet6_csk_dst_check(struct sock * sk,u32 cookie)74 struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
75 {
76 	return __sk_dst_check(sk, cookie);
77 }
78 
inet6_csk_route_socket(struct sock * sk,struct flowi6 * fl6)79 static 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 
inet6_csk_xmit(struct sock * sk,struct sk_buff * skb,struct flowi * fl_unused)114 int 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 }
140 EXPORT_SYMBOL_GPL(inet6_csk_xmit);
141 
inet6_csk_update_pmtu(struct sock * sk,u32 mtu)142 struct 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 }
154 EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);
155