[NETFILTER]: nf_nat: use HW checksumming when possible
When mangling packets forwarded to a HW checksumming capable device,
offload recalculation of the checksum instead of doing it in software.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/nf_nat_helper.c b/net/ipv4/netfilter/nf_nat_helper.c
index 8a40fbe..15b6e5c 100644
--- a/net/ipv4/netfilter/nf_nat_helper.c
+++ b/net/ipv4/netfilter/nf_nat_helper.c
@@ -153,6 +153,7 @@
const char *rep_buffer,
unsigned int rep_len)
{
+ struct rtable *rt = (struct rtable *)(*pskb)->dst;
struct iphdr *iph;
struct tcphdr *tcph;
int oldlen, datalen;
@@ -176,11 +177,22 @@
datalen = (*pskb)->len - iph->ihl*4;
if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {
- tcph->check = 0;
- tcph->check = tcp_v4_check(datalen,
- iph->saddr, iph->daddr,
- csum_partial((char *)tcph,
- datalen, 0));
+ if (!(rt->rt_flags & RTCF_LOCAL) &&
+ (*pskb)->dev->features & NETIF_F_ALL_CSUM) {
+ (*pskb)->ip_summed = CHECKSUM_PARTIAL;
+ (*pskb)->csum_start = skb_headroom(*pskb) +
+ skb_network_offset(*pskb) +
+ iph->ihl * 4;
+ (*pskb)->csum_offset = offsetof(struct tcphdr, check);
+ tcph->check = ~tcp_v4_check(datalen,
+ iph->saddr, iph->daddr, 0);
+ } else {
+ tcph->check = 0;
+ tcph->check = tcp_v4_check(datalen,
+ iph->saddr, iph->daddr,
+ csum_partial((char *)tcph,
+ datalen, 0));
+ }
} else
nf_proto_csum_replace2(&tcph->check, *pskb,
htons(oldlen), htons(datalen), 1);
@@ -217,6 +229,7 @@
const char *rep_buffer,
unsigned int rep_len)
{
+ struct rtable *rt = (struct rtable *)(*pskb)->dst;
struct iphdr *iph;
struct udphdr *udph;
int datalen, oldlen;
@@ -251,13 +264,25 @@
return 1;
if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {
- udph->check = 0;
- udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
- datalen, IPPROTO_UDP,
- csum_partial((char *)udph,
- datalen, 0));
- if (!udph->check)
- udph->check = CSUM_MANGLED_0;
+ if (!(rt->rt_flags & RTCF_LOCAL) &&
+ (*pskb)->dev->features & NETIF_F_ALL_CSUM) {
+ (*pskb)->ip_summed = CHECKSUM_PARTIAL;
+ (*pskb)->csum_start = skb_headroom(*pskb) +
+ skb_network_offset(*pskb) +
+ iph->ihl * 4;
+ (*pskb)->csum_offset = offsetof(struct udphdr, check);
+ udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
+ datalen, IPPROTO_UDP,
+ 0);
+ } else {
+ udph->check = 0;
+ udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
+ datalen, IPPROTO_UDP,
+ csum_partial((char *)udph,
+ datalen, 0));
+ if (!udph->check)
+ udph->check = CSUM_MANGLED_0;
+ }
} else
nf_proto_csum_replace2(&udph->check, *pskb,
htons(oldlen), htons(datalen), 1);