[ospfd/isisd] Switch to lib/ Fletcher checksum, fixing bug in isisd
2008-08-13 Jingjing Duan <Jingjing.Duan@sun.com>
* ospfd/: Remove the old checksum implementation and
use the consolidated version.
* isisd/: ditto, thus fixing isisd checksuming on big-endian.
Signed-off-by: Paul Jakma <paul@quagga.net>
diff --git a/isisd/iso_checksum.c b/isisd/iso_checksum.c
index 16f18e5..294fe99 100644
--- a/isisd/iso_checksum.c
+++ b/isisd/iso_checksum.c
@@ -23,6 +23,7 @@
#include <zebra.h>
#include "iso_checksum.h"
+#include "checksum.h"
/*
* Calculations of the OSI checksum.
@@ -47,14 +48,10 @@
int
iso_csum_verify (u_char * buffer, int len, uint16_t * csum)
{
- u_int8_t *p;
+ u_int16_t checksum;
u_int32_t c0;
u_int32_t c1;
- u_int16_t checksum;
- int i, partial_len;
- p = buffer;
- checksum = 0;
c0 = *csum & 0xff00;
c1 = *csum & 0x00ff;
@@ -70,124 +67,11 @@
if (c0 == 0 || c1 == 0)
return 1;
- /*
- * Otherwise initialize to zero and calculate...
- */
- c0 = 0;
- c1 = 0;
+ /* Offset of checksum from the start of the buffer */
+ int offset = (u_char *) csum - buffer;
- while (len)
- {
- partial_len = MIN(len, 5803);
-
- for (i = 0; i < partial_len; i++)
- {
- c0 = c0 + *(p++);
- c1 += c0;
- }
-
- c0 = c0 % 255;
- c1 = c1 % 255;
-
- len -= partial_len;
- }
-
- if (c0 == 0 && c1 == 0)
+ checksum = fletcher_checksum(buffer, len, offset);
+ if (checksum == *csum)
return 0;
-
return 1;
}
-
-/*
- * Creates the checksum. *csum points to the position of the checksum in the
- * PDU.
- * Based on Annex C.4 of ISO/IEC 8473
- */
-#define FIXED_CODE
-u_int16_t
-iso_csum_create (u_char * buffer, int len, u_int16_t n)
-{
-
- u_int8_t *p;
- int x;
- int y;
- u_int32_t mul;
- u_int32_t c0;
- u_int32_t c1;
- u_int16_t checksum;
- u_int16_t *csum;
- int i, init_len, partial_len;
-
- checksum = 0;
-
- /*
- * Zero the csum in the packet.
- */
- csum = (u_int16_t *) (buffer + n);
- *(csum) = checksum;
-
- p = buffer;
- c0 = 0;
- c1 = 0;
- init_len = len;
-
- while (len != 0)
- {
- partial_len = MIN(len, 5803);
-
- for (i = 0; i < partial_len; i++)
- {
- c0 = c0 + *(p++);
- c1 += c0;
- }
-
- c0 = c0 % 255;
- c1 = c1 % 255;
-
- len -= partial_len;
- }
-
- mul = (init_len - n)*(c0);
-
-#ifdef FIXED_CODE
- x = mul - c0 - c1;
- y = c1 - mul - 1;
-
- if (y > 0)
- y++;
- if (x < 0)
- x--;
-
- x %= 255;
- y %= 255;
-
- if (x == 0)
- x = 255;
- if (y == 0)
- y = 1;
-
- checksum = (y << 8) | (x & 0xFF);
-
-#else
- x = mul - c0 - c1;
- x %= 255;
-
- y = c1 - mul - 1;
- y %= 255;
-
- if (x == 0)
- x = 255;
- if (y == 0)
- y = 255;
-
- checksum = ((y << 8) | x);
-#endif
-
- /*
- * Now we write this to the packet
- */
- *(csum) = checksum;
-
- /* return the checksum for user usage */
- return checksum;
-}