X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fcsum.c;h=33ec28b646fad4140910a5f6f0219560999f7f92;hb=54ae6fa8f1ae7401652d282609848605fc283104;hp=6f044473e2f87607ccdd071e87f28540b25a048d;hpb=34e63086edddcae06d7c1a4fa84fec0861e50758;p=openvswitch

diff --git a/lib/csum.c b/lib/csum.c
index 6f044473..33ec28b6 100644
--- a/lib/csum.c
+++ b/lib/csum.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
 
 #include <config.h>
 #include "csum.h"
+#include "unaligned.h"
 
 /* Returns the IP checksum of the 'n' bytes in 'data'.
  *
@@ -57,8 +58,8 @@ csum_continue(uint32_t partial, const void *data_, size_t n)
 {
     const uint16_t *data = data_;
 
-    for (; n > 1; n -= 2) {
-        partial = csum_add16(partial, *data++);
+    for (; n > 1; n -= 2, data++) {
+        partial = csum_add16(partial, get_unaligned_u16(data));
     }
     if (n) {
         partial += *(uint8_t *) data;
@@ -76,7 +77,10 @@ csum_continue(uint32_t partial, const void *data_, size_t n)
 uint16_t
 csum_finish(uint32_t partial)
 {
-    return ~((partial & 0xffff) + (partial >> 16));
+    while (partial >> 16) {
+        partial = (partial & 0xffff) + (partial >> 16);
+    }
+    return ~partial;
 }
 
 /* Returns the new checksum for a packet in which the checksum field previously
@@ -93,8 +97,7 @@ recalc_csum16(uint16_t old_csum, uint16_t old_u16, uint16_t new_u16)
     uint16_t m_complement = ~old_u16;
     uint16_t m_prime = new_u16;
     uint32_t sum = hc_complement + m_complement + m_prime;
-    uint16_t hc_prime_complement = sum + (sum >> 16);
-    return ~hc_prime_complement;
+    return csum_finish(sum);
 }
 
 /* Returns the new checksum for a packet in which the checksum field previously