linux/net/ipv6/ip6_icmp.c
Jason A. Donenfeld 0b41713b60 icmp: introduce helper for nat'd source address in network device context
This introduces a helper function to be called only by network drivers
that wraps calls to icmp[v6]_send in a conntrack transformation, in case
NAT has been used. We don't want to pollute the non-driver path, though,
so we introduce this as a helper to be called by places that actually
make use of this, as suggested by Florian.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-13 14:19:00 -08:00

83 lines
1.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/export.h>
#include <linux/icmpv6.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include <net/ipv6.h>
#if IS_ENABLED(CONFIG_IPV6)
static ip6_icmp_send_t __rcu *ip6_icmp_send;
int inet6_register_icmp_sender(ip6_icmp_send_t *fn)
{
return (cmpxchg((ip6_icmp_send_t **)&ip6_icmp_send, NULL, fn) == NULL) ?
0 : -EBUSY;
}
EXPORT_SYMBOL(inet6_register_icmp_sender);
int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn)
{
int ret;
ret = (cmpxchg((ip6_icmp_send_t **)&ip6_icmp_send, fn, NULL) == fn) ?
0 : -EINVAL;
synchronize_net();
return ret;
}
EXPORT_SYMBOL(inet6_unregister_icmp_sender);
void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
{
ip6_icmp_send_t *send;
rcu_read_lock();
send = rcu_dereference(ip6_icmp_send);
if (!send)
goto out;
send(skb, type, code, info, NULL);
out:
rcu_read_unlock();
}
EXPORT_SYMBOL(icmpv6_send);
#if IS_ENABLED(CONFIG_NF_NAT)
#include <net/netfilter/nf_conntrack.h>
void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info)
{
struct sk_buff *cloned_skb = NULL;
enum ip_conntrack_info ctinfo;
struct in6_addr orig_ip;
struct nf_conn *ct;
ct = nf_ct_get(skb_in, &ctinfo);
if (!ct || !(ct->status & IPS_SRC_NAT)) {
icmpv6_send(skb_in, type, code, info);
return;
}
if (skb_shared(skb_in))
skb_in = cloned_skb = skb_clone(skb_in, GFP_ATOMIC);
if (unlikely(!skb_in || skb_network_header(skb_in) < skb_in->head ||
(skb_network_header(skb_in) + sizeof(struct ipv6hdr)) >
skb_tail_pointer(skb_in) || skb_ensure_writable(skb_in,
skb_network_offset(skb_in) + sizeof(struct ipv6hdr))))
goto out;
orig_ip = ipv6_hdr(skb_in)->saddr;
ipv6_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.in6;
icmpv6_send(skb_in, type, code, info);
ipv6_hdr(skb_in)->saddr = orig_ip;
out:
consume_skb(cloned_skb);
}
EXPORT_SYMBOL(icmpv6_ndo_send);
#endif
#endif