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