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                             bool reuseport_ok)
  34 {
  35         const struct sock *sk2;
  36         bool reuse = !!sk->sk_reuse;
  37         bool reuseport = !!sk->sk_reuseport && reuseport_ok;
  38         kuid_t uid = sock_i_uid((struct sock *)sk);
  39
  40         /* We must walk the whole port owner list in this case. -DaveM */
  41         /*
  42          * See comment in inet_csk_bind_conflict about sock lookup
  43          * vs net namespaces issues.
  44          */
  45         sk_for_each_bound(sk2, &tb->owners) {
  46                 if (sk != sk2 &&
  47                     (!sk->sk_bound_dev_if ||
  48                      !sk2->sk_bound_dev_if ||
  49                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
  50                         if ((!reuse || !sk2->sk_reuse ||
  51                              sk2->sk_state == TCP_LISTEN) &&
  52                             (!reuseport || !sk2->sk_reuseport ||
  53                              rcu_access_pointer(sk->sk_reuseport_cb) ||
  54                              (sk2->sk_state != TCP_TIME_WAIT &&
  55                               !uid_eq(uid,
  56                                       sock_i_uid((struct sock *)sk2))))) {
  57                                 if (ipv6_rcv_saddr_equal(sk, sk2, true))
  58                                         break;
  59                         }
  60                         if (!relax && reuse && sk2->sk_reuse &&
  61                             sk2->sk_state != TCP_LISTEN &&
  62                             ipv6_rcv_saddr_equal(sk, sk2, true))
  63                                 break;
  64                 }
  65         }
  66
  67         return sk2 != NULL;
  68 }
  69 EXPORT_SYMBOL_GPL(inet6_csk_bind_conflict);
  70
  71 struct dst_entry *inet6_csk_route_req(const struct sock *sk,
  72                                       struct flowi6 *fl6,
  73                                       const struct request_sock *req,
  74                                       u8 proto)
  75 {
  76         struct inet_request_sock *ireq = inet_rsk(req);
  77         const struct ipv6_pinfo *np = inet6_sk(sk);
  78         struct in6_addr *final_p, final;
  79         struct dst_entry *dst;
  80
  81         memset(fl6, 0, sizeof(*fl6));
  82         fl6->flowi6_proto = proto;
  83         fl6->daddr = ireq->ir_v6_rmt_addr;
  84         rcu_read_lock();
  85         final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
  86         rcu_read_unlock();
  87         fl6->saddr = ireq->ir_v6_loc_addr;
  88         fl6->flowi6_oif = ireq->ir_iif;
  89         fl6->flowi6_mark = ireq->ir_mark;
  90         fl6->fl6_dport = ireq->ir_rmt_port;
  91         fl6->fl6_sport = htons(ireq->ir_num);
  92         fl6->flowi6_uid = sk->sk_uid;
  93         security_req_classify_flow(req, flowi6_to_flowi(fl6));
  94
  95         dst = ip6_dst_lookup_flow(sk, fl6, final_p);
  96         if (IS_ERR(dst))
  97                 return NULL;
  98
  99         return dst;
 100 }
 101 EXPORT_SYMBOL(inet6_csk_route_req);
 102
 103 void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
 104 {
 105         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;
 106
 107         sin6->sin6_family = AF_INET6;
 108         sin6->sin6_addr = sk->sk_v6_daddr;
 109         sin6->sin6_port = inet_sk(sk)->inet_dport;
 110         /* We do not store received flowlabel for TCP */
 111         sin6->sin6_flowinfo = 0;
 112         sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
 113                                                   sk->sk_bound_dev_if);
 114 }
 115 EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
 116
 117 static inline
 118 struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
 119 {
 120         return __sk_dst_check(sk, cookie);
 121 }
 122
 123 static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
 124                                                 struct flowi6 *fl6)
 125 {
 126         struct inet_sock *inet = inet_sk(sk);
 127         struct ipv6_pinfo *np = inet6_sk(sk);
 128         struct in6_addr *final_p, final;
 129         struct dst_entry *dst;
 130
 131         memset(fl6, 0, sizeof(*fl6));
 132         fl6->flowi6_proto = sk->sk_protocol;
 133         fl6->daddr = sk->sk_v6_daddr;
 134         fl6->saddr = np->saddr;
 135         fl6->flowlabel = np->flow_label;
 136         IP6_ECN_flow_xmit(sk, fl6->flowlabel);
 137         fl6->flowi6_oif = sk->sk_bound_dev_if;
 138         fl6->flowi6_mark = sk->sk_mark;
 139         fl6->fl6_sport = inet->inet_sport;
 140         fl6->fl6_dport = inet->inet_dport;
 141         fl6->flowi6_uid = sk->sk_uid;
 142         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 143
 144         rcu_read_lock();
 145         final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
 146         rcu_read_unlock();
 147
 148         dst = __inet6_csk_dst_check(sk, np->dst_cookie);
 149         if (!dst) {
 150                 dst = ip6_dst_lookup_flow(sk, fl6, final_p);
 151
 152                 if (!IS_ERR(dst))
 153                         ip6_dst_store(sk, dst, NULL, NULL);
 154         }
 155         return dst;
 156 }
 157
 158 int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused)
 159 {
 160         struct ipv6_pinfo *np = inet6_sk(sk);
 161         struct flowi6 fl6;
 162         struct dst_entry *dst;
 163         int res;
 164
 165         dst = inet6_csk_route_socket(sk, &fl6);
 166         if (IS_ERR(dst)) {
 167                 sk->sk_err_soft = -PTR_ERR(dst);
 168                 sk->sk_route_caps = 0;
 169                 kfree_skb(skb);
 170                 return PTR_ERR(dst);
 171         }
 172
 173         rcu_read_lock();
 174         skb_dst_set_noref(skb, dst);
 175
 176         /* Restore final destination back after routing done */
 177         fl6.daddr = sk->sk_v6_daddr;
 178
 179         res = ip6_xmit(sk, skb, &fl6, rcu_dereference(np->opt),
 180                        np->tclass);
 181         rcu_read_unlock();
 182         return res;
 183 }
 184 EXPORT_SYMBOL_GPL(inet6_csk_xmit);
 185
 186 struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu)
 187 {
 188         struct flowi6 fl6;
 189         struct dst_entry *dst = inet6_csk_route_socket(sk, &fl6);
 190
 191         if (IS_ERR(dst))
 192                 return NULL;
 193         dst->ops->update_pmtu(dst, sk, NULL, mtu);
 194
 195         dst = inet6_csk_route_socket(sk, &fl6);
 196         return IS_ERR(dst) ? NULL : dst;
 197 }
 198 EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);