net/ipv6/inet6_connection_sock.c

   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/module.h>
  17 #include <linux/in6.h>
  18 #include <linux/ipv6.h>
  19 #include <linux/jhash.h>
  20 #include <linux/slab.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, bool relax)
  32 {
  33         const struct sock *sk2;
  34         int reuse = sk->sk_reuse;
  35         int reuseport = sk->sk_reuseport;
  36         kuid_t uid = sock_i_uid((struct sock *)sk);
  37
  38         /* We must walk the whole port owner list in this case. -DaveM */
  39         /*
  40          * See comment in inet_csk_bind_conflict about sock lookup
  41          * vs net namespaces issues.
  42          */
  43         sk_for_each_bound(sk2, &tb->owners) {
  44                 if (sk != sk2 &&
  45                     (!sk->sk_bound_dev_if ||
  46                      !sk2->sk_bound_dev_if ||
  47                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
  48                         if ((!reuse || !sk2->sk_reuse ||
  49                              sk2->sk_state == TCP_LISTEN) &&
  50                             (!reuseport || !sk2->sk_reuseport ||
  51                              (sk2->sk_state != TCP_TIME_WAIT &&
  52                               !uid_eq(uid,
  53                                       sock_i_uid((struct sock *)sk2))))) {
  54                                 if (ipv6_rcv_saddr_equal(sk, sk2))
  55                                         break;
  56                         }
  57                         if (!relax && reuse && sk2->sk_reuse &&
  58                             sk2->sk_state != TCP_LISTEN &&
  59                             ipv6_rcv_saddr_equal(sk, sk2))
  60                                 break;
  61                 }
  62         }
  63
  64         return sk2 != NULL;
  65 }
  66
  67 EXPORT_SYMBOL_GPL(inet6_csk_bind_conflict);
  68
  69 struct dst_entry *inet6_csk_route_req(struct sock *sk,
  70                                       struct flowi6 *fl6,
  71                                       const struct request_sock *req)
  72 {
  73         struct inet6_request_sock *treq = inet6_rsk(req);
  74         struct ipv6_pinfo *np = inet6_sk(sk);
  75         struct in6_addr *final_p, final;
  76         struct dst_entry *dst;
  77
  78         memset(fl6, 0, sizeof(*fl6));
  79         fl6->flowi6_proto = IPPROTO_TCP;
  80         fl6->daddr = treq->rmt_addr;
  81         final_p = fl6_update_dst(fl6, np->opt, &final);
  82         fl6->saddr = treq->loc_addr;
  83         fl6->flowi6_oif = treq->iif;
  84         fl6->flowi6_mark = sk->sk_mark;
  85         fl6->fl6_dport = inet_rsk(req)->rmt_port;
  86         fl6->fl6_sport = inet_rsk(req)->loc_port;
  87         security_req_classify_flow(req, flowi6_to_flowi(fl6));
  88
  89         dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);
  90         if (IS_ERR(dst))
  91                 return NULL;
  92
  93         return dst;
  94 }
  95
  96 /*
  97  * request_sock (formerly open request) hash tables.
  98  */
  99 static u32 inet6_synq_hash(const struct in6_addr *raddr, const __be16 rport,
 100                            const u32 rnd, const u32 synq_hsize)
 101 {
 102         u32 c;
 103
 104         c = jhash_3words((__force u32)raddr->s6_addr32[0],
 105                          (__force u32)raddr->s6_addr32[1],
 106                          (__force u32)raddr->s6_addr32[2],
 107                          rnd);
 108
 109         c = jhash_2words((__force u32)raddr->s6_addr32[3],
 110                          (__force u32)rport,
 111                          c);
 112
 113         return c & (synq_hsize - 1);
 114 }
 115
 116 struct request_sock *inet6_csk_search_req(const struct sock *sk,
 117                                           struct request_sock ***prevp,
 118                                           const __be16 rport,
 119                                           const struct in6_addr *raddr,
 120                                           const struct in6_addr *laddr,
 121                                           const int iif)
 122 {
 123         const struct inet_connection_sock *icsk = inet_csk(sk);
 124         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
 125         struct request_sock *req, **prev;
 126
 127         for (prev = &lopt->syn_table[inet6_synq_hash(raddr, rport,
 128                                                      lopt->hash_rnd,
 129                                                      lopt->nr_table_entries)];
 130              (req = *prev) != NULL;
 131              prev = &req->dl_next) {
 132                 const struct inet6_request_sock *treq = inet6_rsk(req);
 133
 134                 if (inet_rsk(req)->rmt_port == rport &&
 135                     req->rsk_ops->family == AF_INET6 &&
 136                     ipv6_addr_equal(&treq->rmt_addr, raddr) &&
 137                     ipv6_addr_equal(&treq->loc_addr, laddr) &&
 138                     (!treq->iif || treq->iif == iif)) {
 139                         WARN_ON(req->sk != NULL);
 140                         *prevp = prev;
 141                         return req;
 142                 }
 143         }
 144
 145         return NULL;
 146 }
 147
 148 EXPORT_SYMBOL_GPL(inet6_csk_search_req);
 149
 150 void inet6_csk_reqsk_queue_hash_add(struct sock *sk,
 151                                     struct request_sock *req,
 152                                     const unsigned long timeout)
 153 {
 154         struct inet_connection_sock *icsk = inet_csk(sk);
 155         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
 156         const u32 h = inet6_synq_hash(&inet6_rsk(req)->rmt_addr,
 157                                       inet_rsk(req)->rmt_port,
 158                                       lopt->hash_rnd, lopt->nr_table_entries);
 159
 160         reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
 161         inet_csk_reqsk_queue_added(sk, timeout);
 162 }
 163
 164 EXPORT_SYMBOL_GPL(inet6_csk_reqsk_queue_hash_add);
 165
 166 void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr)
 167 {
 168         struct ipv6_pinfo *np = inet6_sk(sk);
 169         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;
 170
 171         sin6->sin6_family = AF_INET6;
 172         sin6->sin6_addr = np->daddr;
 173         sin6->sin6_port = inet_sk(sk)->inet_dport;
 174         /* We do not store received flowlabel for TCP */
 175         sin6->sin6_flowinfo = 0;
 176         sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
 177                                                   sk->sk_bound_dev_if);
 178 }
 179
 180 EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
 181
 182 static inline
 183 void __inet6_csk_dst_store(struct sock *sk, struct dst_entry *dst,
 184                            const struct in6_addr *daddr,
 185                            const struct in6_addr *saddr)
 186 {
 187         __ip6_dst_store(sk, dst, daddr, saddr);
 188 }
 189
 190 static inline
 191 struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
 192 {
 193         return __sk_dst_check(sk, cookie);
 194 }
 195
 196 static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
 197                                                 struct flowi6 *fl6)
 198 {
 199         struct inet_sock *inet = inet_sk(sk);
 200         struct ipv6_pinfo *np = inet6_sk(sk);
 201         struct in6_addr *final_p, final;
 202         struct dst_entry *dst;
 203
 204         memset(fl6, 0, sizeof(*fl6));
 205         fl6->flowi6_proto = sk->sk_protocol;
 206         fl6->daddr = np->daddr;
 207         fl6->saddr = np->saddr;
 208         fl6->flowlabel = np->flow_label;
 209         IP6_ECN_flow_xmit(sk, fl6->flowlabel);
 210         fl6->flowi6_oif = sk->sk_bound_dev_if;
 211         fl6->flowi6_mark = sk->sk_mark;
 212         fl6->fl6_sport = inet->inet_sport;
 213         fl6->fl6_dport = inet->inet_dport;
 214         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 215
 216         final_p = fl6_update_dst(fl6, np->opt, &final);
 217
 218         dst = __inet6_csk_dst_check(sk, np->dst_cookie);
 219         if (!dst) {
 220                 dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);
 221
 222                 if (!IS_ERR(dst))
 223                         __inet6_csk_dst_store(sk, dst, NULL, NULL);
 224         }
 225         return dst;
 226 }
 227
 228 int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl_unused)
 229 {
 230         struct sock *sk = skb->sk;
 231         struct ipv6_pinfo *np = inet6_sk(sk);
 232         struct flowi6 fl6;
 233         struct dst_entry *dst;
 234         int res;
 235
 236         dst = inet6_csk_route_socket(sk, &fl6);
 237         if (IS_ERR(dst)) {
 238                 sk->sk_err_soft = -PTR_ERR(dst);
 239                 sk->sk_route_caps = 0;
 240                 kfree_skb(skb);
 241                 return PTR_ERR(dst);
 242         }
 243
 244         rcu_read_lock();
 245         skb_dst_set_noref(skb, dst);
 246
 247         /* Restore final destination back after routing done */
 248         fl6.daddr = np->daddr;
 249
 250         res = ip6_xmit(sk, skb, &fl6, np->opt, np->tclass);
 251         rcu_read_unlock();
 252         return res;
 253 }
 254 EXPORT_SYMBOL_GPL(inet6_csk_xmit);
 255
 256 struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu)
 257 {
 258         struct flowi6 fl6;
 259         struct dst_entry *dst = inet6_csk_route_socket(sk, &fl6);
 260
 261         if (IS_ERR(dst))
 262                 return NULL;
 263         dst->ops->update_pmtu(dst, sk, NULL, mtu);
 264
 265         dst = inet6_csk_route_socket(sk, &fl6);
 266         return IS_ERR(dst) ? NULL : dst;
 267 }
 268 EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);