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sctp: Clean up sctp checksumming code

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The sctp crc32c checksum is always generated in little endian.
So, we clean up the code to treat it as little endian and remove
all the __force casts.

Suggested by Herbert Xu.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Yasevich 2009-02-13 08:33:42 +00:00 committed by David S. Miller
parent 06e868066e
commit 4458f04c02
4 changed files with 20 additions and 21 deletions
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2
include/linux/sctp.h
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@ -60,7 +60,7 @@ typedef struct sctphdr {
__be16 source; __be16 source;
__be16 dest; __be16 dest;
__be32 vtag; __be32 vtag;
__be32 checksum; __le32 checksum;
} __attribute__((packed)) sctp_sctphdr_t; } __attribute__((packed)) sctp_sctphdr_t;
#ifdef __KERNEL__ #ifdef __KERNEL__

14
include/net/sctp/checksum.h
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@ -46,14 +46,14 @@
#include <net/sctp/sctp.h> #include <net/sctp/sctp.h>
#include <linux/crc32c.h> #include <linux/crc32c.h>
static inline __be32 sctp_crc32c(__be32 crc, u8 *buffer, u16 length) static inline __u32 sctp_crc32c(__u32 crc, u8 *buffer, u16 length)
{ {
return (__force __be32)crc32c((__force u32)crc, buffer, length); return crc32c(crc, buffer, length);
} }
static inline __be32 sctp_start_cksum(__u8 *buffer, __u16 length) static inline __u32 sctp_start_cksum(__u8 *buffer, __u16 length)
{ {
__be32 crc = ~cpu_to_be32(0); __u32 crc = ~(__u32)0;
__u8 zero[sizeof(__u32)] = {0}; __u8 zero[sizeof(__u32)] = {0};
/* Optimize this routine to be SCTP specific, knowing how /* Optimize this routine to be SCTP specific, knowing how
@ -72,12 +72,12 @@ static inline __be32 sctp_start_cksum(__u8 *buffer, __u16 length)
return crc; return crc;
} }
static inline __be32 sctp_update_cksum(__u8 *buffer, __u16 length, __be32 crc32) static inline __u32 sctp_update_cksum(__u8 *buffer, __u16 length, __u32 crc32)
{ {
return sctp_crc32c(crc32, buffer, length); return sctp_crc32c(crc32, buffer, length);
} }
static inline __be32 sctp_end_cksum(__be32 crc32) static inline __le32 sctp_end_cksum(__be32 crc32)
{ {
return (__force __be32)~cpu_to_le32((__force u32)crc32); return cpu_to_le32(~crc32);
} }

11
net/sctp/input.c
View File

@ -83,14 +83,15 @@ static inline int sctp_rcv_checksum(struct sk_buff *skb)
{ {
struct sk_buff *list = skb_shinfo(skb)->frag_list; struct sk_buff *list = skb_shinfo(skb)->frag_list;
struct sctphdr *sh = sctp_hdr(skb); struct sctphdr *sh = sctp_hdr(skb);
__be32 cmp = sh->checksum; __le32 cmp = sh->checksum;
__be32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); __le32 val;
__u32 tmp = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
for (; list; list = list->next) for (; list; list = list->next)
val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), tmp = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
val); tmp);
val = sctp_end_cksum(val); val = sctp_end_cksum(tmp);
if (val != cmp) { if (val != cmp) {
/* CRC failure, dump it. */ /* CRC failure, dump it. */

10
net/sctp/output.c
View File

@ -367,7 +367,6 @@ int sctp_packet_transmit(struct sctp_packet *packet)
struct sctp_transport *tp = packet->transport; struct sctp_transport *tp = packet->transport;
struct sctp_association *asoc = tp->asoc; struct sctp_association *asoc = tp->asoc;
struct sctphdr *sh; struct sctphdr *sh;
__be32 crc32 = cpu_to_be32(0);
struct sk_buff *nskb; struct sk_buff *nskb;
struct sctp_chunk *chunk, *tmp; struct sctp_chunk *chunk, *tmp;
struct sock *sk; struct sock *sk;
@ -532,15 +531,14 @@ int sctp_packet_transmit(struct sctp_packet *packet)
* by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>. * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>.
*/ */
if (!sctp_checksum_disable && !(dst->dev->features & NETIF_F_NO_CSUM)) { if (!sctp_checksum_disable && !(dst->dev->features & NETIF_F_NO_CSUM)) {
crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len); __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
crc32 = sctp_end_cksum(crc32);
} else
nskb->ip_summed = CHECKSUM_UNNECESSARY;
/* 3) Put the resultant value into the checksum field in the /* 3) Put the resultant value into the checksum field in the
* common header, and leave the rest of the bits unchanged. * common header, and leave the rest of the bits unchanged.
*/ */
sh->checksum = crc32; sh->checksum = sctp_end_cksum(crc32);
} else
nskb->ip_summed = CHECKSUM_UNNECESSARY;
/* IP layer ECN support /* IP layer ECN support
* From RFC 2481 * From RFC 2481