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 #include <net/sock_reuseport.h>
  30
  31 int inet6_csk_bind_conflict(const struct sock *sk,
  32                             const struct inet_bind_bucket *tb, bool relax)
  33 {
  34         const struct sock *sk2;
  35         int reuse = sk->sk_reuse;
  36         int reuseport = sk->sk_reuseport;
  37         kuid_t uid = sock_i_uid((struct sock *)sk);
  38
  39         /* We must walk the whole port owner list in this case. -DaveM */
  40         /*
  41          * See comment in inet_csk_bind_conflict about sock lookup
  42          * vs net namespaces issues.
  43          */
  44         sk_for_each_bound(sk2, &tb->owners) {
  45                 if (sk != sk2 &&
  46                     (!sk->sk_bound_dev_if ||
  47                      !sk2->sk_bound_dev_if ||
  48                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
  49                         if ((!reuse || !sk2->sk_reuse ||
  50                              sk2->sk_state == TCP_LISTEN) &&
  51                             (!reuseport || !sk2->sk_reuseport ||
  52                              rcu_access_pointer(sk->sk_reuseport_cb) ||
  53                              (sk2->sk_state != TCP_TIME_WAIT &&
  54                               !uid_eq(uid,
  55                                       sock_i_uid((struct sock *)sk2))))) {
  56                                 if (ipv6_rcv_saddr_equal(sk, sk2, true))
  57                                         break;
  58                         }
  59                         if (!relax && reuse && sk2->sk_reuse &&
  60                             sk2->sk_state != TCP_LISTEN &&
  61                             ipv6_rcv_saddr_equal(sk, sk2, true))
  62                                 break;
  63                 }
  64         }
  65
  66         return sk2 != NULL;
  67 }
  68 EXPORT_SYMBOL_GPL(inet6_csk_bind_conflict);
  69
  70 struct dst_entry *inet6_csk_route_req(const struct sock *sk,
  71                                       struct flowi6 *fl6,
  72                                       const struct request_sock *req,
  73                                       u8 proto)
  74 {
  75         struct inet_request_sock *ireq = inet_rsk(req);
  76         const struct ipv6_pinfo *np = inet6_sk(sk);
  77         struct in6_addr *final_p, final;
  78         struct dst_entry *dst;
  79
  80         memset(fl6, 0, sizeof(*fl6));
  81         fl6->flowi6_proto = proto;
  82         fl6->daddr = ireq->ir_v6_rmt_addr;
  83         rcu_read_lock();
  84         final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
  85         rcu_read_unlock();
  86         fl6->saddr = ireq->ir_v6_loc_addr;
  87         fl6->flowi6_oif = ireq->ir_iif;
  88         fl6->flowi6_mark = ireq->ir_mark;
  89         fl6->fl6_dport = ireq->ir_rmt_port;
  90         fl6->fl6_sport = htons(ireq->ir_num);
  91         security_req_classify_flow(req, flowi6_to_flowi(fl6));
  92
  93         dst = ip6_dst_lookup_flow(sk, fl6, final_p);
  94         if (IS_ERR(dst))
  95                 return NULL;
  96
  97         return dst;
  98 }
  99 EXPORT_SYMBOL(inet6_csk_route_req);
 100
 101 void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
 102 {
 103         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;
 104
 105         sin6->sin6_family = AF_INET6;
 106         sin6->sin6_addr = sk->sk_v6_daddr;
 107         sin6->sin6_port = inet_sk(sk)->inet_dport;
 108         /* We do not store received flowlabel for TCP */
 109         sin6->sin6_flowinfo = 0;
 110         sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
 111                                                   sk->sk_bound_dev_if);
 112 }
 113 EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
 114
 115 static inline
 116 struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
 117 {
 118         return __sk_dst_check(sk, cookie);
 119 }
 120
 121 static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
 122                                                 struct flowi6 *fl6)
 123 {
 124         struct inet_sock *inet = inet_sk(sk);
 125         struct ipv6_pinfo *np = inet6_sk(sk);
 126         struct in6_addr *final_p, final;
 127         struct dst_entry *dst;
 128
 129         memset(fl6, 0, sizeof(*fl6));
 130         fl6->flowi6_proto = sk->sk_protocol;
 131         fl6->daddr = sk->sk_v6_daddr;
 132         fl6->saddr = np->saddr;
 133         fl6->flowlabel = np->flow_label;
 134         IP6_ECN_flow_xmit(sk, fl6->flowlabel);
 135         fl6->flowi6_oif = sk->sk_bound_dev_if;
 136         fl6->flowi6_mark = sk->sk_mark;
 137         fl6->fl6_sport = inet->inet_sport;
 138         fl6->fl6_dport = inet->inet_dport;
 139         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 140
 141         rcu_read_lock();
 142         final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
 143         rcu_read_unlock();
 144
 145         dst = __inet6_csk_dst_check(sk, np->dst_cookie);
 146         if (!dst) {
 147                 dst = ip6_dst_lookup_flow(sk, fl6, final_p);
 148
 149                 if (!IS_ERR(dst))
 150                         ip6_dst_store(sk, dst, NULL, NULL);
 151         }
 152         return dst;
 153 }
 154
 155 int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused)
 156 {
 157         struct ipv6_pinfo *np = inet6_sk(sk);
 158         struct flowi6 fl6;
 159         struct dst_entry *dst;
 160         int res;
 161
 162         dst = inet6_csk_route_socket(sk, &fl6);
 163         if (IS_ERR(dst)) {
 164                 sk->sk_err_soft = -PTR_ERR(dst);
 165                 sk->sk_route_caps = 0;
 166                 kfree_skb(skb);
 167                 return PTR_ERR(dst);
 168         }
 169
 170         rcu_read_lock();
 171         skb_dst_set_noref(skb, dst);
 172
 173         /* Restore final destination back after routing done */
 174         fl6.daddr = sk->sk_v6_daddr;
 175
 176         res = ip6_xmit(sk, skb, &fl6, rcu_dereference(np->opt),
 177                        np->tclass);
 178         rcu_read_unlock();
 179         return res;
 180 }
 181 EXPORT_SYMBOL_GPL(inet6_csk_xmit);
 182
 183 struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu)
 184 {
 185         struct flowi6 fl6;
 186         struct dst_entry *dst = inet6_csk_route_socket(sk, &fl6);
 187
 188         if (IS_ERR(dst))
 189                 return NULL;
 190         dst->ops->update_pmtu(dst, sk, NULL, mtu);
 191
 192         dst = inet6_csk_route_socket(sk, &fl6);
 193         return IS_ERR(dst) ? NULL : dst;
 194 }
 195 EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);