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 EXPORT_SYMBOL_GPL(inet6_csk_bind_conflict);
  67
  68 struct dst_entry *inet6_csk_route_req(struct sock *sk,
  69                                       struct flowi6 *fl6,
  70                                       const struct request_sock *req)
  71 {
  72         struct inet_request_sock *ireq = inet_rsk(req);
  73         struct ipv6_pinfo *np = inet6_sk(sk);
  74         struct in6_addr *final_p, final;
  75         struct dst_entry *dst;
  76
  77         memset(fl6, 0, sizeof(*fl6));
  78         fl6->flowi6_proto = IPPROTO_TCP;
  79         fl6->daddr = ireq->ir_v6_rmt_addr;
  80         rcu_read_lock();
  81         final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
  82         rcu_read_unlock();
  83         fl6->saddr = ireq->ir_v6_loc_addr;
  84         fl6->flowi6_oif = ireq->ir_iif;
  85         fl6->flowi6_mark = ireq->ir_mark;
  86         fl6->fl6_dport = ireq->ir_rmt_port;
  87         fl6->fl6_sport = htons(ireq->ir_num);
  88         security_req_classify_flow(req, flowi6_to_flowi(fl6));
  89
  90         dst = ip6_dst_lookup_flow(sk, fl6, final_p);
  91         if (IS_ERR(dst))
  92                 return NULL;
  93
  94         return dst;
  95 }
  96
  97 /*
  98  * request_sock (formerly open request) hash tables.
  99  */
 100 static u32 inet6_synq_hash(const struct in6_addr *raddr, const __be16 rport,
 101                            const u32 rnd, const u32 synq_hsize)
 102 {
 103         u32 c;
 104
 105         c = jhash_3words((__force u32)raddr->s6_addr32[0],
 106                          (__force u32)raddr->s6_addr32[1],
 107                          (__force u32)raddr->s6_addr32[2],
 108                          rnd);
 109
 110         c = jhash_2words((__force u32)raddr->s6_addr32[3],
 111                          (__force u32)rport,
 112                          c);
 113
 114         return c & (synq_hsize - 1);
 115 }
 116
 117 struct request_sock *inet6_csk_search_req(struct sock *sk,
 118                                           const __be16 rport,
 119                                           const struct in6_addr *raddr,
 120                                           const struct in6_addr *laddr,
 121                                           const int iif)
 122 {
 123         struct inet_connection_sock *icsk = inet_csk(sk);
 124         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
 125         struct request_sock *req;
 126         u32 hash = inet6_synq_hash(raddr, rport, lopt->hash_rnd,
 127                                    lopt->nr_table_entries);
 128
 129         spin_lock(&icsk->icsk_accept_queue.syn_wait_lock);
 130         for (req = lopt->syn_table[hash]; req != NULL; req = req->dl_next) {
 131                 const struct inet_request_sock *ireq = inet_rsk(req);
 132
 133                 if (ireq->ir_rmt_port == rport &&
 134                     req->rsk_ops->family == AF_INET6 &&
 135                     ipv6_addr_equal(&ireq->ir_v6_rmt_addr, raddr) &&
 136                     ipv6_addr_equal(&ireq->ir_v6_loc_addr, laddr) &&
 137                     (!ireq->ir_iif || ireq->ir_iif == iif)) {
 138                         atomic_inc(&req->rsk_refcnt);
 139                         WARN_ON(req->sk != NULL);
 140                         break;
 141                 }
 142         }
 143         spin_unlock(&icsk->icsk_accept_queue.syn_wait_lock);
 144
 145         return req;
 146 }
 147 EXPORT_SYMBOL_GPL(inet6_csk_search_req);
 148
 149 void inet6_csk_reqsk_queue_hash_add(struct sock *sk,
 150                                     struct request_sock *req,
 151                                     const unsigned long timeout)
 152 {
 153         struct inet_connection_sock *icsk = inet_csk(sk);
 154         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
 155         const u32 h = inet6_synq_hash(&inet_rsk(req)->ir_v6_rmt_addr,
 156                                       inet_rsk(req)->ir_rmt_port,
 157                                       lopt->hash_rnd, lopt->nr_table_entries);
 158
 159         reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
 160         inet_csk_reqsk_queue_added(sk, timeout);
 161 }
 162 EXPORT_SYMBOL_GPL(inet6_csk_reqsk_queue_hash_add);
 163
 164 void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
 165 {
 166         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;
 167
 168         sin6->sin6_family = AF_INET6;
 169         sin6->sin6_addr = sk->sk_v6_daddr;
 170         sin6->sin6_port = inet_sk(sk)->inet_dport;
 171         /* We do not store received flowlabel for TCP */
 172         sin6->sin6_flowinfo = 0;
 173         sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
 174                                                   sk->sk_bound_dev_if);
 175 }
 176 EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
 177
 178 static inline
 179 void __inet6_csk_dst_store(struct sock *sk, struct dst_entry *dst,
 180                            const struct in6_addr *daddr,
 181                            const struct in6_addr *saddr)
 182 {
 183         __ip6_dst_store(sk, dst, daddr, saddr);
 184 }
 185
 186 static inline
 187 struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
 188 {
 189         return __sk_dst_check(sk, cookie);
 190 }
 191
 192 static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
 193                                                 struct flowi6 *fl6)
 194 {
 195         struct inet_sock *inet = inet_sk(sk);
 196         struct ipv6_pinfo *np = inet6_sk(sk);
 197         struct in6_addr *final_p, final;
 198         struct dst_entry *dst;
 199
 200         memset(fl6, 0, sizeof(*fl6));
 201         fl6->flowi6_proto = sk->sk_protocol;
 202         fl6->daddr = sk->sk_v6_daddr;
 203         fl6->saddr = np->saddr;
 204         fl6->flowlabel = np->flow_label;
 205         IP6_ECN_flow_xmit(sk, fl6->flowlabel);
 206         fl6->flowi6_oif = sk->sk_bound_dev_if;
 207         fl6->flowi6_mark = sk->sk_mark;
 208         fl6->fl6_sport = inet->inet_sport;
 209         fl6->fl6_dport = inet->inet_dport;
 210         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 211
 212         rcu_read_lock();
 213         final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
 214         rcu_read_unlock();
 215
 216         dst = __inet6_csk_dst_check(sk, np->dst_cookie);
 217         if (!dst) {
 218                 dst = ip6_dst_lookup_flow(sk, fl6, final_p);
 219
 220                 if (!IS_ERR(dst))
 221                         __inet6_csk_dst_store(sk, dst, NULL, NULL);
 222         }
 223         return dst;
 224 }
 225
 226 int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused)
 227 {
 228         struct ipv6_pinfo *np = inet6_sk(sk);
 229         struct flowi6 fl6;
 230         struct dst_entry *dst;
 231         int res;
 232
 233         dst = inet6_csk_route_socket(sk, &fl6);
 234         if (IS_ERR(dst)) {
 235                 sk->sk_err_soft = -PTR_ERR(dst);
 236                 sk->sk_route_caps = 0;
 237                 kfree_skb(skb);
 238                 return PTR_ERR(dst);
 239         }
 240
 241         rcu_read_lock();
 242         skb_dst_set_noref(skb, dst);
 243
 244         /* Restore final destination back after routing done */
 245         fl6.daddr = sk->sk_v6_daddr;
 246
 247         res = ip6_xmit(sk, skb, &fl6, rcu_dereference(np->opt),
 248                        np->tclass);
 249         rcu_read_unlock();
 250         return res;
 251 }
 252 EXPORT_SYMBOL_GPL(inet6_csk_xmit);
 253
 254 struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu)
 255 {
 256         struct flowi6 fl6;
 257         struct dst_entry *dst = inet6_csk_route_socket(sk, &fl6);
 258
 259         if (IS_ERR(dst))
 260                 return NULL;
 261         dst->ops->update_pmtu(dst, sk, NULL, mtu);
 262
 263         dst = inet6_csk_route_socket(sk, &fl6);
 264         return IS_ERR(dst) ? NULL : dst;
 265 }
 266 EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);