inet6_connection_sock.c

  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_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
 58static inline
 59struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
 60{
 61	return __sk_dst_check(sk, cookie);
 62}
 63
 64static 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, false, false);
 95	}
 96	return dst;
 97}
 98
 99int 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}
125EXPORT_SYMBOL_GPL(inet6_csk_xmit);
126
127struct 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}