[NETFILTER]: Add address family specific checksum helpers
Add checksum operation which takes care of verifying the checksum and
dealing with HW checksum errors and avoids multiple checksum
operations by setting ip_summed to CHECKSUM_UNNECESSARY after
successful verification.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index b25339c..6a9e34b 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -161,8 +161,41 @@
return 0;
}
+unsigned int nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
+ unsigned int dataoff, u_int8_t protocol)
+{
+ struct iphdr *iph = skb->nh.iph;
+ unsigned int csum = 0;
+
+ switch (skb->ip_summed) {
+ case CHECKSUM_HW:
+ if (hook != NF_IP_PRE_ROUTING && hook != NF_IP_LOCAL_IN)
+ break;
+ if ((protocol == 0 && !(u16)csum_fold(skb->csum)) ||
+ !csum_tcpudp_magic(iph->saddr, iph->daddr,
+ skb->len - dataoff, protocol,
+ skb->csum)) {
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ break;
+ }
+ /* fall through */
+ case CHECKSUM_NONE:
+ if (protocol == 0)
+ skb->csum = 0;
+ else
+ skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
+ skb->len - dataoff,
+ protocol, 0);
+ csum = __skb_checksum_complete(skb);
+ }
+ return csum;
+}
+
+EXPORT_SYMBOL(nf_ip_checksum);
+
static struct nf_afinfo nf_ip_afinfo = {
.family = AF_INET,
+ .checksum = nf_ip_checksum,
.saveroute = nf_ip_saveroute,
.reroute = nf_ip_reroute,
.route_key_size = sizeof(struct ip_rt_info),