1 /*
2  * INET        An implementation of the TCP/IP protocol suite for the LINUX
3  *             operating system.  INET is implemented using the  BSD Socket
4  *             interface as the means of communication with the user level.
5  *
6  *             Support for INET6 connection oriented protocols.
7  *
8  * Authors:    See the TCPv6 sources
9  *
10  *             This program is free software; you can redistribute it and/or
11  *             modify it under the terms of the GNU General Public License
12  *             as published by the Free Software Foundation; either version
13  *             2 of the License, or(at your option) any later version.
14  */
15 
16 #include <linux/config.h>
17 #include <linux/module.h>
18 #include <linux/in6.h>
19 #include <linux/ipv6.h>
20 #include <linux/jhash.h>
21 
22 #include <net/addrconf.h>
23 #include <net/inet_connection_sock.h>
24 #include <net/inet_ecn.h>
25 #include <net/inet_hashtables.h>
26 #include <net/ip6_route.h>
27 #include <net/sock.h>
28 #include <net/inet6_connection_sock.h>
29 
30 int inet6_csk_bind_conflict(const struct sock *sk,
31 			    const struct inet_bind_bucket *tb)
32 {
33 	const struct sock *sk2;
34 	const struct hlist_node *node;
35 
36 	/* We must walk the whole port owner list in this case. -DaveM */
37 	sk_for_each_bound(sk2, node, &tb->owners) {
38 		if (sk != sk2 &&
39 		    (!sk->sk_bound_dev_if ||
40 		     !sk2->sk_bound_dev_if ||
41 		     sk->sk_bound_dev_if == sk2->sk_bound_dev_if) &&
42 		    (!sk->sk_reuse || !sk2->sk_reuse ||
43 		     sk2->sk_state == TCP_LISTEN) &&
44 		     ipv6_rcv_saddr_equal(sk, sk2))
45 			break;
46 	}
47 
48 	return node != NULL;
49 }
50 
51 EXPORT_SYMBOL_GPL(inet6_csk_bind_conflict);
52 
53 /*
54  * request_sock (formerly open request) hash tables.
55  */
56 static u32 inet6_synq_hash(const struct in6_addr *raddr, const u16 rport,
57 			   const u32 rnd, const u16 synq_hsize)
58 {
59 	u32 a = raddr->s6_addr32[0];
60 	u32 b = raddr->s6_addr32[1];
61 	u32 c = raddr->s6_addr32[2];
62 
63 	a += JHASH_GOLDEN_RATIO;
64 	b += JHASH_GOLDEN_RATIO;
65 	c += rnd;
66 	__jhash_mix(a, b, c);
67 
68 	a += raddr->s6_addr32[3];
69 	b += (u32)rport;
70 	__jhash_mix(a, b, c);
71 
72 	return c & (synq_hsize - 1);
73 }
74 
75 struct request_sock *inet6_csk_search_req(const struct sock *sk,
76 					  struct request_sock ***prevp,
77 					  const __u16 rport,
78 					  const struct in6_addr *raddr,
79 					  const struct in6_addr *laddr,
80 					  const int iif)
81 {
82 	const struct inet_connection_sock *icsk = inet_csk(sk);
83 	struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
84 	struct request_sock *req, **prev;
85 
86 	for (prev = &lopt->syn_table[inet6_synq_hash(raddr, rport,
87 						     lopt->hash_rnd,
88 						     lopt->nr_table_entries)];
89 	     (req = *prev) != NULL;
90 	     prev = &req->dl_next) {
91 		const struct inet6_request_sock *treq = inet6_rsk(req);
92 
93 		if (inet_rsk(req)->rmt_port == rport &&
94 		    req->rsk_ops->family == AF_INET6 &&
95 		    ipv6_addr_equal(&treq->rmt_addr, raddr) &&
96 		    ipv6_addr_equal(&treq->loc_addr, laddr) &&
97 		    (!treq->iif || treq->iif == iif)) {
98 			BUG_TRAP(req->sk == NULL);
99 			*prevp = prev;
100 			return req;
101 		}
102 	}
103 
104 	return NULL;
105 }
106 
107 EXPORT_SYMBOL_GPL(inet6_csk_search_req);
108 
109 void inet6_csk_reqsk_queue_hash_add(struct sock *sk,
110 				    struct request_sock *req,
111 				    const unsigned long timeout)
112 {
113 	struct inet_connection_sock *icsk = inet_csk(sk);
114 	struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
115 	const u32 h = inet6_synq_hash(&inet6_rsk(req)->rmt_addr,
116 				      inet_rsk(req)->rmt_port,
117 				      lopt->hash_rnd, lopt->nr_table_entries);
118 
119 	reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
120 	inet_csk_reqsk_queue_added(sk, timeout);
121 }
122 
123 EXPORT_SYMBOL_GPL(inet6_csk_reqsk_queue_hash_add);
124 
125 void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr)
126 {
127 	struct ipv6_pinfo *np = inet6_sk(sk);
128 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;
129 
130 	sin6->sin6_family = AF_INET6;
131 	ipv6_addr_copy(&sin6->sin6_addr, &np->daddr);
132 	sin6->sin6_port	= inet_sk(sk)->dport;
133 	/* We do not store received flowlabel for TCP */
134 	sin6->sin6_flowinfo = 0;
135 	sin6->sin6_scope_id = 0;
136 	if (sk->sk_bound_dev_if &&
137 	    ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
138 		sin6->sin6_scope_id = sk->sk_bound_dev_if;
139 }
140 
141 EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
142 
143 int inet6_csk_xmit(struct sk_buff *skb, int ipfragok)
144 {
145 	struct sock *sk = skb->sk;
146 	struct inet_sock *inet = inet_sk(sk);
147 	struct ipv6_pinfo *np = inet6_sk(sk);
148 	struct flowi fl;
149 	struct dst_entry *dst;
150 	struct in6_addr *final_p = NULL, final;
151 
152 	memset(&fl, 0, sizeof(fl));
153 	fl.proto = sk->sk_protocol;
154 	ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
155 	ipv6_addr_copy(&fl.fl6_src, &np->saddr);
156 	fl.fl6_flowlabel = np->flow_label;
157 	IP6_ECN_flow_xmit(sk, fl.fl6_flowlabel);
158 	fl.oif = sk->sk_bound_dev_if;
159 	fl.fl_ip_sport = inet->sport;
160 	fl.fl_ip_dport = inet->dport;
161 
162 	if (np->opt && np->opt->srcrt) {
163 		struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
164 		ipv6_addr_copy(&final, &fl.fl6_dst);
165 		ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
166 		final_p = &final;
167 	}
168 
169 	dst = __sk_dst_check(sk, np->dst_cookie);
170 
171 	if (dst == NULL) {
172 		int err = ip6_dst_lookup(sk, &dst, &fl);
173 
174 		if (err) {
175 			sk->sk_err_soft = -err;
176 			return err;
177 		}
178 
179 		if (final_p)
180 			ipv6_addr_copy(&fl.fl6_dst, final_p);
181 
182 		if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0) {
183 			sk->sk_route_caps = 0;
184 			return err;
185 		}
186 
187 		ip6_dst_store(sk, dst, NULL);
188 		sk->sk_route_caps = dst->dev->features &
189 			~(NETIF_F_IP_CSUM | NETIF_F_TSO);
190 	}
191 
192 	skb->dst = dst_clone(dst);
193 
194 	/* Restore final destination back after routing done */
195 	ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
196 
197 	return ip6_xmit(sk, skb, &fl, np->opt, 0);
198 }
199 
200 EXPORT_SYMBOL_GPL(inet6_csk_xmit);
201