[NETFILTER]: Add partial checksum validation helper
Move the UDP-Lite conntrack checksum validation to a generic helper
similar to nf_checksum() and make it fall back to nf_checksum()
in case the full packet is to be checksummed and hardware checksums
are available. This is to be used by DCCP conntrack, which also
needs to verify partial checksums.
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index 9a904c6..f8edacd 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -182,21 +182,44 @@
}
return csum;
}
-
EXPORT_SYMBOL(nf_ip_checksum);
+static __sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
+ unsigned int dataoff, unsigned int len,
+ u_int8_t protocol)
+{
+ const struct iphdr *iph = ip_hdr(skb);
+ __sum16 csum = 0;
+
+ switch (skb->ip_summed) {
+ case CHECKSUM_COMPLETE:
+ if (len == skb->len - dataoff)
+ return nf_ip_checksum(skb, hook, dataoff, protocol);
+ /* fall through */
+ case CHECKSUM_NONE:
+ skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, protocol,
+ skb->len - dataoff, 0);
+ skb->ip_summed = CHECKSUM_NONE;
+ csum = __skb_checksum_complete_head(skb, dataoff + len);
+ if (!csum)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ }
+ return csum;
+}
+
static int nf_ip_route(struct dst_entry **dst, struct flowi *fl)
{
return ip_route_output_key(&init_net, (struct rtable **)dst, fl);
}
static const struct nf_afinfo nf_ip_afinfo = {
- .family = AF_INET,
- .checksum = nf_ip_checksum,
- .route = nf_ip_route,
- .saveroute = nf_ip_saveroute,
- .reroute = nf_ip_reroute,
- .route_key_size = sizeof(struct ip_rt_info),
+ .family = AF_INET,
+ .checksum = nf_ip_checksum,
+ .checksum_partial = nf_ip_checksum_partial,
+ .route = nf_ip_route,
+ .saveroute = nf_ip_saveroute,
+ .reroute = nf_ip_reroute,
+ .route_key_size = sizeof(struct ip_rt_info),
};
static int ipv4_netfilter_init(void)