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authorPatrick McHardy <kaber@trash.net>2008-03-20 17:15:53 +0300
committerPatrick McHardy <kaber@trash.net>2008-04-14 13:15:49 +0400
commitd63a650736f566a1f9e9434725d2089597c0d2cc (patch)
treef0a3d5dbc9ced46f95582e4133b55bb70a1ae365 /net/ipv4
parent6185f870e293a0a3eae5c81eb0106480cf03dfde (diff)
downloadlinux-d63a650736f566a1f9e9434725d2089597c0d2cc.tar.xz
[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>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/netfilter.c37
1 files changed, 30 insertions, 7 deletions
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index 9a904c6c0dc8..f8edacdf991d 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -182,21 +182,44 @@ __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
}
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)