[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/isis_lsp.c b/isisd/isis_lsp.c
index 1a4deb1..48e3147 100644
--- a/isisd/isis_lsp.c
+++ b/isisd/isis_lsp.c
@@ -33,6 +33,7 @@
#include "command.h"
#include "hash.h"
#include "if.h"
+#include "checksum.h"
#include "isisd/dict.h"
#include "isisd/isis_constants.h"
@@ -45,7 +46,6 @@
#include "isisd/isis_dynhn.h"
#include "isisd/isis_misc.h"
#include "isisd/isis_flags.h"
-#include "isisd/iso_checksum.h"
#include "isisd/isis_csm.h"
#include "isisd/isis_adjacency.h"
#include "isisd/isis_spf.h"
@@ -314,7 +314,7 @@
newseq = seq_num++;
lsp->lsp_header->seq_num = htonl (newseq);
- iso_csum_create (STREAM_DATA (lsp->pdu) + 12,
+ fletcher_checksum (STREAM_DATA (lsp->pdu) + 12,
ntohs (lsp->lsp_header->pdu_len) - 12, 12);
return;
@@ -1803,7 +1803,7 @@
tlv_add_is_neighs (lsp->tlv_data.es_neighs, lsp->pdu);
lsp->lsp_header->pdu_len = htons (stream_get_endp (lsp->pdu));
- iso_csum_create (STREAM_DATA (lsp->pdu) + 12,
+ fletcher_checksum (STREAM_DATA (lsp->pdu) + 12,
ntohs (lsp->lsp_header->pdu_len) - 12, 12);
list_delete (adj_list);
@@ -2071,7 +2071,7 @@
lsp->lsp_header->pdu_len =
htons (ISIS_FIXED_HDR_LEN + ISIS_LSP_HDR_LEN);
lsp->purged = 0;
- iso_csum_create (STREAM_DATA (lsp->pdu) + 12,
+ fletcher_checksum (STREAM_DATA (lsp->pdu) + 12,
ntohs (lsp->lsp_header->pdu_len) - 12, 12);
ISIS_FLAGS_SET_ALL (lsp->SRMflags);
}
diff --git a/isisd/isis_pdu.c b/isisd/isis_pdu.c
index 6fcc5ed..4311a90 100644
--- a/isisd/isis_pdu.c
+++ b/isisd/isis_pdu.c
@@ -32,6 +32,7 @@
#include "hash.c"
#include "prefix.h"
#include "if.h"
+#include "checksum.h"
#include "isisd/dict.h"
#include "isisd/include-netbsd/iso.h"
@@ -1121,7 +1122,7 @@
if (isis->debugs & DEBUG_UPDATE_PACKETS)
zlog_debug ("LSP LEN: %d",
ntohs (lsp->lsp_header->pdu_len));
- iso_csum_create (STREAM_DATA (lsp->pdu) + 12,
+ fletcher_checksum (STREAM_DATA (lsp->pdu) + 12,
ntohs (lsp->lsp_header->pdu_len) - 12, 12);
ISIS_FLAGS_SET_ALL (lsp->SRMflags);
if (isis->debugs & DEBUG_UPDATE_PACKETS)
@@ -1164,7 +1165,7 @@
/* 7.3.16.1 */
lsp->lsp_header->seq_num = htonl (ntohl (hdr->seq_num) + 1);
- iso_csum_create (STREAM_DATA (lsp->pdu) + 12,
+ fletcher_checksum (STREAM_DATA (lsp->pdu) + 12,
ntohs (lsp->lsp_header->pdu_len) - 12, 12);
ISIS_FLAGS_SET_ALL (lsp->SRMflags);
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;
-}
diff --git a/isisd/iso_checksum.h b/isisd/iso_checksum.h
index ba0d198..5f8d41f 100644
--- a/isisd/iso_checksum.h
+++ b/isisd/iso_checksum.h
@@ -24,6 +24,5 @@
#define _ZEBRA_ISO_CSUM_H
int iso_csum_verify (u_char * buffer, int len, uint16_t * csum);
-u_int16_t iso_csum_create (u_char * buffer, int len, u_int16_t n);
#endif /* _ZEBRA_ISO_CSUM_H */
diff --git a/ospfd/ospf_lsa.c b/ospfd/ospf_lsa.c
index 243928f..f453353 100644
--- a/ospfd/ospf_lsa.c
+++ b/ospfd/ospf_lsa.c
@@ -32,6 +32,7 @@
#include "thread.h"
#include "hash.h"
#include "sockunion.h" /* for inet_aton() */
+#include "checksum.h"
#include "ospfd/ospfd.h"
#include "ospfd/ospf_interface.h"
@@ -172,46 +173,23 @@
/* Fletcher Checksum -- Refer to RFC1008. */
-#define MODX 4102
-#define LSA_CHECKSUM_OFFSET 15
+/* All the offsets are zero-based. The offsets in the RFC1008 are
+ one-based. */
u_int16_t
ospf_lsa_checksum (struct lsa_header *lsa)
{
- u_char *sp, *ep, *p, *q;
- int c0 = 0, c1 = 0;
- int x, y;
- u_int16_t length;
+ u_char *buffer = (u_char *) &lsa->options;
+ int options_offset = buffer - (u_char *) &lsa->ls_age; /* should be 2 */
- lsa->checksum = 0;
- length = ntohs (lsa->length) - 2;
- sp = (u_char *) &lsa->options;
+ /* Skip the AGE field */
+ u_int16_t len = ntohs(lsa->length) - options_offset;
- for (ep = sp + length; sp < ep; sp = q)
- {
- q = sp + MODX;
- if (q > ep)
- q = ep;
- for (p = sp; p < q; p++)
- {
- c0 += *p;
- c1 += c0;
- }
- c0 %= 255;
- c1 %= 255;
- }
+ /* Checksum offset starts from "options" field, not the beginning of the
+ lsa_header struct. The offset is 14, rather than 16. */
+ int checksum_offset = (u_char *) &lsa->checksum - buffer;
- x = (((int)length - LSA_CHECKSUM_OFFSET) * c0 - c1) % 255;
- if (x <= 0)
- x += 255;
- y = 510 - c0 - x;
- if (y > 255)
- y -= 255;
-
- /* take care endian issue. */
- lsa->checksum = htons ((x << 8) + y);
-
- return (lsa->checksum);
+ return fletcher_checksum(buffer, len, checksum_offset);
}