diff options
| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2020-02-11 20:47:05 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-13 14:19:00 -0800 |
| commit | 0b41713b606694257b90d61ba7e2712d8457648b (patch) | |
| tree | 9d2df288a3386102321124f7442d304b7f4fa28e /net/ipv4/icmp.c | |
| parent | 07134cf6962377875288b06232d0c41c69d31752 (diff) | |
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>
Diffstat (limited to 'net/ipv4/icmp.c')
| -rw-r--r-- | net/ipv4/icmp.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 18068ed42f25..f369e7ce685b 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -748,6 +748,39 @@ out:; } EXPORT_SYMBOL(__icmp_send); +#if IS_ENABLED(CONFIG_NF_NAT) +#include <net/netfilter/nf_conntrack.h> +void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info) +{ + struct sk_buff *cloned_skb = NULL; + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + __be32 orig_ip; + + ct = nf_ct_get(skb_in, &ctinfo); + if (!ct || !(ct->status & IPS_SRC_NAT)) { + icmp_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 iphdr)) > + skb_tail_pointer(skb_in) || skb_ensure_writable(skb_in, + skb_network_offset(skb_in) + sizeof(struct iphdr)))) + goto out; + + orig_ip = ip_hdr(skb_in)->saddr; + ip_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.ip; + icmp_send(skb_in, type, code, info); + ip_hdr(skb_in)->saddr = orig_ip; +out: + consume_skb(cloned_skb); +} +EXPORT_SYMBOL(icmp_ndo_send); +#endif static void icmp_socket_deliver(struct sk_buff *skb, u32 info) { |