sctp: remove unnecessary byteshifting, calculate directly in big-endian

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 20 insertions, 15 deletions

diff --git a/include/net/sctp/checksum.h b/include/net/sctp/checksum.h
index ba75c67cb992..b799fb21519a 100644
--- a/include/net/sctp/checksum.h
+++ b/include/net/sctp/checksum.h
@@ -46,9 +46,14 @@
 #include <net/sctp/sctp.h>
 #include <linux/crc32c.h>
 
-static inline __u32 sctp_start_cksum(__u8 *buffer, __u16 length)
+static inline __be32 sctp_crc32c(__be32 crc, u8 *buffer, u16 length)
 {
-        __u32 crc = ~(__u32) 0;
+        return (__force __be32)crc32c((__force u32)crc, buffer, length);
+}
+
+static inline __be32 sctp_start_cksum(__u8 *buffer, __u16 length)
+{
+        __be32 crc = ~cpu_to_be32(0);
         __u8  zero[sizeof(__u32)] = {0};
 
         /* Optimize this routine to be SCTP specific, knowing how
@@ -56,23 +61,23 @@ static inline __u32 sctp_start_cksum(__u8 *buffer, __u16 length)
          */
 
         /* Calculate CRC up to the checksum. */
-        crc = crc32c(crc, buffer, sizeof(struct sctphdr) - sizeof(__u32));
+        crc = sctp_crc32c(crc, buffer, sizeof(struct sctphdr) - sizeof(__u32));
 
         /* Skip checksum field of the header. */
-        crc = crc32c(crc, zero, sizeof(__u32));
+        crc = sctp_crc32c(crc, zero, sizeof(__u32));
 
         /* Calculate the rest of the CRC. */
-        crc = crc32c(crc, &buffer[sizeof(struct sctphdr)],
+        crc = sctp_crc32c(crc, &buffer[sizeof(struct sctphdr)],
                             length - sizeof(struct sctphdr));
         return crc;
 }
 
-static inline __u32 sctp_update_cksum(__u8 *buffer, __u16 length, __u32 crc32)
+static inline __be32 sctp_update_cksum(__u8 *buffer, __u16 length, __be32 crc32)
 {
-        return crc32c(crc32, buffer, length);
+        return sctp_crc32c(crc32, buffer, length);
 }
 
-static inline __u32 sctp_end_cksum(__u32 crc32)
+static inline __be32 sctp_end_cksum(__be32 crc32)
 {
-        return ntohl(~crc32);
+        return ~crc32;
 }
diff --git a/net/ipv4/netfilter/nf_nat_proto_sctp.c b/net/ipv4/netfilter/nf_nat_proto_sctp.c
index 82e4c0e286b8..65e470bc6123 100644
--- a/net/ipv4/netfilter/nf_nat_proto_sctp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_sctp.c
@@ -36,7 +36,7 @@ sctp_manip_pkt(struct sk_buff *skb,
         sctp_sctphdr_t *hdr;
         unsigned int hdroff = iphdroff + iph->ihl*4;
         __be32 oldip, newip;
-        u32 crc32;
+        __be32 crc32;
 
         if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
                 return false;
@@ -61,7 +61,7 @@ sctp_manip_pkt(struct sk_buff *skb,
                 crc32 = sctp_update_cksum((u8 *)skb->data, skb_headlen(skb),
                                           crc32);
         crc32 = sctp_end_cksum(crc32);
-        hdr->checksum = htonl(crc32);
+        hdr->checksum = crc32;
 
         return true;
 }
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 5ed93c05c23e..a49fa80b57b9 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -83,8 +83,8 @@ 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);
-        __u32 cmp = ntohl(sh->checksum);
-        __u32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
+        __be32 cmp = sh->checksum;
+        __be32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
 
         for (; list; list = list->next)
                 val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 9a63a3fb9011..45684646b1db 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -365,7 +365,7 @@ int sctp_packet_transmit(struct sctp_packet *packet)
         struct sctp_transport *tp = packet->transport;
         struct sctp_association *asoc = tp->asoc;
         struct sctphdr *sh;
-        __u32 crc32 = 0;
+        __be32 crc32 = __constant_cpu_to_be32(0);
         struct sk_buff *nskb;
         struct sctp_chunk *chunk, *tmp;
         struct sock *sk;
@@ -538,7 +538,7 @@ int sctp_packet_transmit(struct sctp_packet *packet)
         /* 3) Put the resultant value into the checksum field in the
          *    common header, and leave the rest of the bits unchanged.
          */
-        sh->checksum = htonl(crc32);
+        sh->checksum = crc32;
 
         /* IP layer ECN support
          * From RFC 2481