sctp: Clean up sctp checksumming code
authorVlad Yasevich <vladislav.yasevich@hp.com>
Fri, 13 Feb 2009 08:33:42 +0000 (08:33 +0000)
committerDavid S. Miller <davem@davemloft.net>
Mon, 16 Feb 2009 08:03:10 +0000 (00:03 -0800)
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>
include/linux/sctp.h
include/net/sctp/checksum.h
net/sctp/input.c
net/sctp/output.c

index bd50b371ffaa682737c352c23613e0e55227266f..c2731bfe04d8a3255cc00d35af5b87dfb052895f 100644 (file)
@@ -60,7 +60,7 @@ typedef struct sctphdr {
        __be16 source;
        __be16 dest;
        __be32 vtag;
-       __be32 checksum;
+       __le32 checksum;
 } __attribute__((packed)) sctp_sctphdr_t;
 
 #ifdef __KERNEL__
index 2fec3c366e81cb18a0d10da0f2d506ea44008e9b..befc8d2a1b9f2703b5f31eabfe7c313ae0b05bcd 100644 (file)
 #include <net/sctp/sctp.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};
 
        /* 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;
 }
 
-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);
 }
 
-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);
 }
index 693fd0804810b37462d76af1b764615a7580852c..d2e98803ffe30a5ffba004562ea23c00f59ff1c9 100644 (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 sctphdr *sh = sctp_hdr(skb);
-       __be32 cmp = sh->checksum;
-       __be32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
+       __le32 cmp = sh->checksum;
+       __le32 val;
+       __u32 tmp = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
 
        for (; list; list = list->next)
-               val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
-                                       val);
+               tmp = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
+                                       tmp);
 
-       val = sctp_end_cksum(val);
+       val = sctp_end_cksum(tmp);
 
        if (val != cmp) {
                /* CRC failure, dump it. */
index 2d65b7a7330bbf5a3272075bdcb78bd436b94459..07d58903a74625dd2ec25982a617a6cad2d59ae3 100644 (file)
@@ -367,7 +367,6 @@ int sctp_packet_transmit(struct sctp_packet *packet)
        struct sctp_transport *tp = packet->transport;
        struct sctp_association *asoc = tp->asoc;
        struct sctphdr *sh;
-       __be32 crc32 = cpu_to_be32(0);
        struct sk_buff *nskb;
        struct sctp_chunk *chunk, *tmp;
        struct sock *sk;
@@ -532,16 +531,15 @@ int sctp_packet_transmit(struct sctp_packet *packet)
         * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>.
         */
        if (!sctp_checksum_disable && !(dst->dev->features & NETIF_F_NO_CSUM)) {
-               crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
-               crc32 = sctp_end_cksum(crc32);
+               __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
+
+               /* 3) Put the resultant value into the checksum field in the
+                *    common header, and leave the rest of the bits unchanged.
+                */
+               sh->checksum = sctp_end_cksum(crc32);
        } else
                nskb->ip_summed = CHECKSUM_UNNECESSARY;
 
-       /* 3) Put the resultant value into the checksum field in the
-        *    common header, and leave the rest of the bits unchanged.
-        */
-       sh->checksum = crc32;
-
        /* IP layer ECN support
         * From RFC 2481
         *  "The ECN-Capable Transport (ECT) bit would be set by the