xref: /linux/net/ipv6/ip6_icmp.c (revision 962fad301c33dec69324dc2d9320fd84a119a24c)
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 #if !IS_BUILTIN(CONFIG_IPV6)
13 
14 static ip6_icmp_send_t __rcu *ip6_icmp_send;
15 
16 int inet6_register_icmp_sender(ip6_icmp_send_t *fn)
17 {
18 	return (cmpxchg((ip6_icmp_send_t **)&ip6_icmp_send, NULL, fn) == NULL) ?
19 		0 : -EBUSY;
20 }
21 EXPORT_SYMBOL(inet6_register_icmp_sender);
22 
23 int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn)
24 {
25 	int ret;
26 
27 	ret = (cmpxchg((ip6_icmp_send_t **)&ip6_icmp_send, fn, NULL) == fn) ?
28 	      0 : -EINVAL;
29 
30 	synchronize_net();
31 
32 	return ret;
33 }
34 EXPORT_SYMBOL(inet6_unregister_icmp_sender);
35 
36 void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
37 {
38 	ip6_icmp_send_t *send;
39 
40 	rcu_read_lock();
41 	send = rcu_dereference(ip6_icmp_send);
42 	if (send)
43 		send(skb, type, code, info, NULL);
44 	rcu_read_unlock();
45 }
46 EXPORT_SYMBOL(icmpv6_send);
47 #endif
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
83