net/ipv6/ip6_icmp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/export.h>
   3 #include <linux/icmpv6.h>
   4 #include <linux/mutex.h>
   5 #include <linux/netdevice.h>
   6 #include <linux/spinlock.h>
   7
   8 #include <net/ipv6.h>
   9
  10 #if IS_ENABLED(CONFIG_IPV6)
  11
  12 static ip6_icmp_send_t __rcu *ip6_icmp_send;
  13
  14 int inet6_register_icmp_sender(ip6_icmp_send_t *fn)
  15 {
  16         return (cmpxchg((ip6_icmp_send_t **)&ip6_icmp_send, NULL, fn) == NULL) ?
  17                 0 : -EBUSY;
  18 }
  19 EXPORT_SYMBOL(inet6_register_icmp_sender);
  20
  21 int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn)
  22 {
  23         int ret;
  24
  25         ret = (cmpxchg((ip6_icmp_send_t **)&ip6_icmp_send, fn, NULL) == fn) ?
  26               0 : -EINVAL;
  27
  28         synchronize_net();
  29
  30         return ret;
  31 }
  32 EXPORT_SYMBOL(inet6_unregister_icmp_sender);
  33
  34 void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
  35 {
  36         ip6_icmp_send_t *send;
  37
  38         rcu_read_lock();
  39         send = rcu_dereference(ip6_icmp_send);
  40
  41         if (!send)
  42                 goto out;
  43         send(skb, type, code, info, NULL);
  44 out:
  45         rcu_read_unlock();
  46 }
  47 EXPORT_SYMBOL(icmpv6_send);
  48
  49 #if IS_ENABLED(CONFIG_NF_NAT)
  50 #include <net/netfilter/nf_conntrack.h>
  51 void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info)
  52 {
  53         struct sk_buff *cloned_skb = NULL;
  54         enum ip_conntrack_info ctinfo;
  55         struct in6_addr orig_ip;
  56         struct nf_conn *ct;
  57
  58         ct = nf_ct_get(skb_in, &ctinfo);
  59         if (!ct || !(ct->status & IPS_SRC_NAT)) {
  60                 icmpv6_send(skb_in, type, code, info);
  61                 return;
  62         }
  63
  64         if (skb_shared(skb_in))
  65                 skb_in = cloned_skb = skb_clone(skb_in, GFP_ATOMIC);
  66
  67         if (unlikely(!skb_in || skb_network_header(skb_in) < skb_in->head ||
  68             (skb_network_header(skb_in) + sizeof(struct ipv6hdr)) >
  69             skb_tail_pointer(skb_in) || skb_ensure_writable(skb_in,
  70             skb_network_offset(skb_in) + sizeof(struct ipv6hdr))))
  71                 goto out;
  72
  73         orig_ip = ipv6_hdr(skb_in)->saddr;
  74         ipv6_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.in6;
  75         icmpv6_send(skb_in, type, code, info);
  76         ipv6_hdr(skb_in)->saddr = orig_ip;
  77 out:
  78         consume_skb(cloned_skb);
  79 }
  80 EXPORT_SYMBOL(icmpv6_ndo_send);
  81 #endif
  82 #endif