[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@xxxxxxxxx>
---
commit e291ad784a87e67b09bb6e5fe9668b79cf43953c
tree 7d1e5502cb4d7c5fa8fbb9831641dbf81666b4ff
parent 3eee75c01a5589393289a81daf19215a45f802b9
author Patrick McHardy <kaber@xxxxxxxxx> Thu, 20 Mar 2008 15:15:53 +0100
committer Patrick McHardy <kaber@xxxxxxxxx> Mon, 14 Apr 2008 12:10:52 +0200
include/linux/netfilter.h | 22 +++++++++++++++
net/ipv4/netfilter.c | 37 ++++++++++++++++++++-----
net/ipv6/netfilter.c | 42 +++++++++++++++++++++++-----
net/netfilter/nf_conntrack_proto_udplite.c | 33 +++++-----------------
4 files changed, 94 insertions(+), 40 deletions(-)
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 66bc520..e4c6659 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -234,6 +234,11 @@ struct nf_afinfo {
unsigned short family;
__sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u_int8_t protocol);
+ __sum16 (*checksum_partial)(struct sk_buff *skb,
+ unsigned int hook,
+ unsigned int dataoff,
+ unsigned int len,
+ u_int8_t protocol);
int (*route)(struct dst_entry **dst, struct flowi *fl);
void (*saveroute)(const struct sk_buff *skb,
struct nf_queue_entry *entry);
@@ -263,6 +268,23 @@ nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
return csum;
}
+static inline __sum16
+nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
+ unsigned int dataoff, unsigned int len,
+ u_int8_t protocol, unsigned short family)
+{
+ const struct nf_afinfo *afinfo;
+ __sum16 csum = 0;
+
+ rcu_read_lock();
+ afinfo = nf_get_afinfo(family);
+ if (afinfo)
+ csum = afinfo->checksum_partial(skb, hook, dataoff, len,
+ protocol);
+ rcu_read_unlock();
+ return csum;
+}
+
extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
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 @@ __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)
diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c
index aed51bc..8c6c5e7 100644
--- a/net/ipv6/netfilter.c
+++ b/net/ipv6/netfilter.c
@@ -121,16 +121,44 @@ __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
}
return csum;
}
-
EXPORT_SYMBOL(nf_ip6_checksum);
+static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook,
+ unsigned int dataoff, unsigned int len,
+ u_int8_t protocol)
+{
+ struct ipv6hdr *ip6h = ipv6_hdr(skb);
+ __wsum hsum;
+ __sum16 csum = 0;
+
+ switch (skb->ip_summed) {
+ case CHECKSUM_COMPLETE:
+ if (len == skb->len - dataoff)
+ return nf_ip6_checksum(skb, hook, dataoff, protocol);
+ /* fall through */
+ case CHECKSUM_NONE:
+ hsum = skb_checksum(skb, 0, dataoff, 0);
+ skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr,
+ &ip6h->daddr,
+ skb->len - dataoff,
+ protocol,
+ csum_sub(0, hsum)));
+ skb->ip_summed = CHECKSUM_NONE;
+ csum = __skb_checksum_complete_head(skb, dataoff + len);
+ if (!csum)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ }
+ return csum;
+};
+
static const struct nf_afinfo nf_ip6_afinfo = {
- .family = AF_INET6,
- .checksum = nf_ip6_checksum,
- .route = nf_ip6_route,
- .saveroute = nf_ip6_saveroute,
- .reroute = nf_ip6_reroute,
- .route_key_size = sizeof(struct ip6_rt_info),
+ .family = AF_INET6,
+ .checksum = nf_ip6_checksum,
+ .checksum_partial = nf_ip6_checksum_partial,
+ .route = nf_ip6_route,
+ .saveroute = nf_ip6_saveroute,
+ .reroute = nf_ip6_reroute,
+ .route_key_size = sizeof(struct ip6_rt_info),
};
int __init ipv6_netfilter_init(void)
diff --git a/net/netfilter/nf_conntrack_proto_udplite.c b/net/netfilter/nf_conntrack_proto_udplite.c
index 9dd03c7..c3eaee6 100644
--- a/net/netfilter/nf_conntrack_proto_udplite.c
+++ b/net/netfilter/nf_conntrack_proto_udplite.c
@@ -127,32 +127,13 @@ static int udplite_error(struct sk_buff *skb, unsigned int dataoff,
}
/* Checksum invalid? Ignore. */
- if (nf_conntrack_checksum && !skb_csum_unnecessary(skb) &&
- hooknum == NF_INET_PRE_ROUTING) {
- if (pf == PF_INET) {
- struct iphdr *iph = ip_hdr(skb);
-
- skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
- udplen, IPPROTO_UDPLITE, 0);
- } else {
- struct ipv6hdr *ipv6h = ipv6_hdr(skb);
- __wsum hsum = skb_checksum(skb, 0, dataoff, 0);
-
- skb->csum = ~csum_unfold(
- csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
- udplen, IPPROTO_UDPLITE,
- csum_sub(0, hsum)));
- }
-
- skb->ip_summed = CHECKSUM_NONE;
- if (__skb_checksum_complete_head(skb, dataoff + cscov)) {
- if (LOG_INVALID(IPPROTO_UDPLITE))
- nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
- "nf_ct_udplite: bad UDPLite "
- "checksum ");
- return -NF_ACCEPT;
- }
- skb->ip_summed = CHECKSUM_UNNECESSARY;
+ if (nf_conntrack_checksum && hooknum == NF_INET_PRE_ROUTING &&
+ nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP,
+ pf)) {
+ if (LOG_INVALID(IPPROTO_UDPLITE))
+ nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
+ "nf_ct_udplite: bad UDPLite checksum ");
+ return -NF_ACCEPT;
}
return NF_ACCEPT;
--
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