net/ipv6/inet6_connection_sock.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * INET        An implementation of the TCP/IP protocol suite for the LINUX
   4  *             operating system.  INET is implemented using the  BSD Socket
   5  *             interface as the means of communication with the user level.
   6  *
   7  *             Support for INET6 connection oriented protocols.
   8  *
   9  * Authors:    See the TCPv6 sources
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/in6.h>
  14 #include <linux/ipv6.h>
  15 #include <linux/jhash.h>
  16 #include <linux/slab.h>
  17
  18 #include <net/addrconf.h>
  19 #include <net/inet_connection_sock.h>
  20 #include <net/inet_ecn.h>
  21 #include <net/inet_hashtables.h>
  22 #include <net/ip6_route.h>
  23 #include <net/sock.h>
  24 #include <net/inet6_connection_sock.h>
  25 #include <net/sock_reuseport.h>
  26
  27 struct dst_entry *inet6_csk_route_req(const struct sock *sk,
  28                                       struct flowi6 *fl6,
  29                                       const struct request_sock *req,
  30                                       u8 proto)
  31 {
  32         struct inet_request_sock *ireq = inet_rsk(req);
  33         const struct ipv6_pinfo *np = inet6_sk(sk);
  34         struct in6_addr *final_p, final;
  35         struct dst_entry *dst;
  36
  37         memset(fl6, 0, sizeof(*fl6));
  38         fl6->flowi6_proto = proto;
  39         fl6->daddr = ireq->ir_v6_rmt_addr;
  40         rcu_read_lock();
  41         final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
  42         rcu_read_unlock();
  43         fl6->saddr = ireq->ir_v6_loc_addr;
  44         fl6->flowi6_oif = ireq->ir_iif;
  45         fl6->flowi6_mark = ireq->ir_mark;
  46         fl6->fl6_dport = ireq->ir_rmt_port;
  47         fl6->fl6_sport = htons(ireq->ir_num);
  48         fl6->flowi6_uid = sk->sk_uid;
  49         security_req_classify_flow(req, flowi6_to_flowi(fl6));
  50
  51         dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);
  52         if (IS_ERR(dst))
  53                 return NULL;
  54
  55         return dst;
  56 }
  57 EXPORT_SYMBOL(inet6_csk_route_req);
  58
  59 void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
  60 {
  61         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;
  62
  63         sin6->sin6_family = AF_INET6;
  64         sin6->sin6_addr = sk->sk_v6_daddr;
  65         sin6->sin6_port = inet_sk(sk)->inet_dport;
  66         /* We do not store received flowlabel for TCP */
  67         sin6->sin6_flowinfo = 0;
  68         sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
  69                                                   sk->sk_bound_dev_if);
  70 }
  71 EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
  72
  73 static inline
  74 struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
  75 {
  76         return __sk_dst_check(sk, cookie);
  77 }
  78
  79 static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
  80                                                 struct flowi6 *fl6)
  81 {
  82         struct inet_sock *inet = inet_sk(sk);
  83         struct ipv6_pinfo *np = inet6_sk(sk);
  84         struct in6_addr *final_p, final;
  85         struct dst_entry *dst;
  86
  87         memset(fl6, 0, sizeof(*fl6));
  88         fl6->flowi6_proto = sk->sk_protocol;
  89         fl6->daddr = sk->sk_v6_daddr;
  90         fl6->saddr = np->saddr;
  91         fl6->flowlabel = np->flow_label;
  92         IP6_ECN_flow_xmit(sk, fl6->flowlabel);
  93         fl6->flowi6_oif = sk->sk_bound_dev_if;
  94         fl6->flowi6_mark = sk->sk_mark;
  95         fl6->fl6_sport = inet->inet_sport;
  96         fl6->fl6_dport = inet->inet_dport;
  97         fl6->flowi6_uid = sk->sk_uid;
  98         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
  99
 100         rcu_read_lock();
 101         final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
 102         rcu_read_unlock();
 103
 104         dst = __inet6_csk_dst_check(sk, np->dst_cookie);
 105         if (!dst) {
 106                 dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);
 107
 108                 if (!IS_ERR(dst))
 109                         ip6_dst_store(sk, dst, NULL, NULL);
 110         }
 111         return dst;
 112 }
 113
 114 int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused)
 115 {
 116         struct ipv6_pinfo *np = inet6_sk(sk);
 117         struct flowi6 fl6;
 118         struct dst_entry *dst;
 119         int res;
 120
 121         dst = inet6_csk_route_socket(sk, &fl6);
 122         if (IS_ERR(dst)) {
 123                 sk->sk_err_soft = -PTR_ERR(dst);
 124                 sk->sk_route_caps = 0;
 125                 kfree_skb(skb);
 126                 return PTR_ERR(dst);
 127         }
 128
 129         rcu_read_lock();
 130         skb_dst_set_noref(skb, dst);
 131
 132         /* Restore final destination back after routing done */
 133         fl6.daddr = sk->sk_v6_daddr;
 134
 135         res = ip6_xmit(sk, skb, &fl6, sk->sk_mark, rcu_dereference(np->opt),
 136                        np->tclass,  sk->sk_priority);
 137         rcu_read_unlock();
 138         return res;
 139 }
 140 EXPORT_SYMBOL_GPL(inet6_csk_xmit);
 141
 142 struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu)
 143 {
 144         struct flowi6 fl6;
 145         struct dst_entry *dst = inet6_csk_route_socket(sk, &fl6);
 146
 147         if (IS_ERR(dst))
 148                 return NULL;
 149         dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
 150
 151         dst = inet6_csk_route_socket(sk, &fl6);
 152         return IS_ERR(dst) ? NULL : dst;
 153 }
 154 EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);