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Date: Thu, 25 Jul 2013 10:52:05 +0900
From: Joe Stringer <joe@...d.net.nz>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, netfilter-devel@...r.kernel.org,
lvs-devel@...r.kernel.org, pablo@...filter.org, ja@....bg,
horms@...ge.net.au, jesse@...ira.com,
Joe Stringer <joe@...d.net.nz>
Subject: [PATCH v2 net-next] net/sctp: Refactor SCTP skb checksum computation
This patch consolidates the SCTP checksum calculation code from various
places to a single new function, sctp_compute_cksum(skb, offset).
Signed-off-by: Joe Stringer <joe@...d.net.nz>
---
v2:
* Use skb->data + offset for start position of checksum calculation
* Fix existing bug in sctp_csum_check() where the incorrect offset was used
* Remove redundant variable in sctp_nat_csum()
---
include/net/sctp/checksum.h | 15 +++++++++++++++
net/netfilter/ipvs/ip_vs_proto_sctp.c | 23 +++--------------------
net/netfilter/nf_nat_proto_sctp.c | 8 +-------
net/sctp/input.c | 10 +---------
4 files changed, 20 insertions(+), 36 deletions(-)
diff --git a/include/net/sctp/checksum.h b/include/net/sctp/checksum.h
index 0cb08e6..5d55082 100644
--- a/include/net/sctp/checksum.h
+++ b/include/net/sctp/checksum.h
@@ -85,4 +85,19 @@ static inline __le32 sctp_end_cksum(__u32 crc32)
return cpu_to_le32(~crc32);
}
+/* Calculate the CRC32C checksum of an SCTP packet. */
+static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
+ unsigned int offset)
+{
+ const struct sk_buff *iter;
+
+ __u32 crc32 = sctp_start_cksum(skb->data + offset,
+ skb_headlen(skb) - offset);
+ skb_walk_frags(skb, iter)
+ crc32 = sctp_update_cksum((__u8 *) iter->data,
+ skb_headlen(iter), crc32);
+
+ return sctp_end_cksum(crc32);
+}
+
#endif /* __sctp_checksum_h__ */
diff --git a/net/netfilter/ipvs/ip_vs_proto_sctp.c b/net/netfilter/ipvs/ip_vs_proto_sctp.c
index 3c0da87..23e596e 100644
--- a/net/netfilter/ipvs/ip_vs_proto_sctp.c
+++ b/net/netfilter/ipvs/ip_vs_proto_sctp.c
@@ -66,15 +66,7 @@ sctp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_proto_data *pd,
static void sctp_nat_csum(struct sk_buff *skb, sctp_sctphdr_t *sctph,
unsigned int sctphoff)
{
- __u32 crc32;
- struct sk_buff *iter;
-
- crc32 = sctp_start_cksum((__u8 *)sctph, skb_headlen(skb) - sctphoff);
- skb_walk_frags(skb, iter)
- crc32 = sctp_update_cksum((u8 *) iter->data,
- skb_headlen(iter), crc32);
- sctph->checksum = sctp_end_cksum(crc32);
-
+ sctph->checksum = sctp_compute_cksum(skb, sctphoff);
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
@@ -151,10 +143,7 @@ sctp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp)
{
unsigned int sctphoff;
struct sctphdr *sh, _sctph;
- struct sk_buff *iter;
- __le32 cmp;
- __le32 val;
- __u32 tmp;
+ __le32 cmp, val;
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6)
@@ -168,13 +157,7 @@ sctp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp)
return 0;
cmp = sh->checksum;
-
- tmp = sctp_start_cksum((__u8 *) sh, skb_headlen(skb));
- skb_walk_frags(skb, iter)
- tmp = sctp_update_cksum((__u8 *) iter->data,
- skb_headlen(iter), tmp);
-
- val = sctp_end_cksum(tmp);
+ val = sctp_compute_cksum(skb, sctphoff);
if (val != cmp) {
/* CRC failure, dump it. */
diff --git a/net/netfilter/nf_nat_proto_sctp.c b/net/netfilter/nf_nat_proto_sctp.c
index 396e55d..754536f 100644
--- a/net/netfilter/nf_nat_proto_sctp.c
+++ b/net/netfilter/nf_nat_proto_sctp.c
@@ -34,9 +34,7 @@ sctp_manip_pkt(struct sk_buff *skb,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
{
- struct sk_buff *frag;
sctp_sctphdr_t *hdr;
- __u32 crc32;
if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
return false;
@@ -51,11 +49,7 @@ sctp_manip_pkt(struct sk_buff *skb,
hdr->dest = tuple->dst.u.sctp.port;
}
- crc32 = sctp_start_cksum((u8 *)hdr, skb_headlen(skb) - hdroff);
- skb_walk_frags(skb, frag)
- crc32 = sctp_update_cksum((u8 *)frag->data, skb_headlen(frag),
- crc32);
- hdr->checksum = sctp_end_cksum(crc32);
+ hdr->checksum = sctp_compute_cksum(skb, hdroff);
return true;
}
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 3fa4d85..944f70e 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -87,15 +87,7 @@ static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb)
{
struct sctphdr *sh = sctp_hdr(skb);
__le32 cmp = sh->checksum;
- struct sk_buff *list;
- __le32 val;
- __u32 tmp = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
-
- skb_walk_frags(skb, list)
- tmp = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
- tmp);
-
- val = sctp_end_cksum(tmp);
+ __le32 val = sctp_compute_cksum(skb, 0);
if (val != cmp) {
/* CRC failure, dump it. */
--
1.7.10.4
--
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