From Michael Mann:

Condense all SCTP CRC routines to wsutil/crc32.[ch]. Also made
crc32_ccitt_table not explicitly accessible (must use crc32_ccitt_table_lookup).

https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6298

svn path=/trunk/; revision=39233

5 files changed, 34 insertions, 25 deletions

diff --git a/epan/dissectors/packet-sctp.c b/epan/dissectors/packet-sctp.c
index 081f5ea8c1..9f657327b7 100644
--- a/epan/dissectors/packet-sctp.c
+++ b/epan/dissectors/packet-sctp.c
@@ -446,23 +446,19 @@ sctp_adler32(const unsigned char* buf, unsigned int len)
 static guint32
 sctp_crc32c(const unsigned char* buf, unsigned int len)
 {
-  unsigned int i;
-  guint32 crc32 = CRC32C_PRELOAD;
+  guint32 crc32,
+          zero = 0;
   guint32 result;
 
-  for (i = 0; i < SOURCE_PORT_LENGTH + DESTINATION_PORT_LENGTH + VERIFICATION_TAG_LENGTH; i++)
-  {
-    CRC32C(crc32, buf[i]);
-  }
+  /* CRC for header */
+  crc32 = crc32c_calculate_no_swap(buf, SOURCE_PORT_LENGTH + DESTINATION_PORT_LENGTH + VERIFICATION_TAG_LENGTH, CRC32C_PRELOAD);
+
   /* handle four 0 bytes as checksum */
-  CRC32C(crc32, 0);
-  CRC32C(crc32, 0);
-  CRC32C(crc32, 0);
-  CRC32C(crc32, 0);
-  for (i = COMMON_HEADER_LENGTH; i < len; i++)
-  {
-    CRC32C(crc32, buf[i]);
-  }
+  crc32 = crc32c_calculate_no_swap(&zero, 4, crc32);
+
+  /* CRC for the rest of the packet */
+  crc32 = crc32c_calculate_no_swap(&buf[COMMON_HEADER_LENGTH], len-COMMON_HEADER_LENGTH, crc32);
+
   result = CRC32C_SWAP(crc32);
 
   return ( ~result );
diff --git a/wsutil/airpdcap_wep.c b/wsutil/airpdcap_wep.c
index 6689535885..29d7d44743 100644
--- a/wsutil/airpdcap_wep.c
+++ b/wsutil/airpdcap_wep.c
@@ -77,7 +77,7 @@ int AirPDcapWepDecrypt(
 		j = (j + S[i]) & 0xff;
 		S_SWAP(i, j);
 		*cypher_text ^= S[(S[i] + S[j]) & 0xff];
-		crc = crc32_ccitt_table[(crc ^ *cypher_text) & 0xff] ^ (crc >> 8);
+		crc = crc32_ccitt_table_lookup((crc ^ *cypher_text) & 0xff) ^ (crc >> 8);
 		cypher_text++;
 	}
 
diff --git a/wsutil/crc32.c b/wsutil/crc32.c
index c40047dffe..5882ba9f5c 100644
--- a/wsutil/crc32.c
+++ b/wsutil/crc32.c
@@ -53,6 +53,8 @@
 /* in the FTP archive "ftp.adelaide.edu.au/pub/rocksoft".        */
 /*                                                               */
 /*****************************************************************/
+#define CRC32C(c,d) (c=(c>>8)^crc32c_table[(c^(d))&0xFF])
+
 static const guint32 crc32c_table[256] = {
 		0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L, 0xC79A971FL,
 		0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL, 0x8AD958CFL, 0x78B2DBCCL,
@@ -115,7 +117,7 @@ static const guint32 crc32c_table[256] = {
  *  x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^8 + x^7 +
  *      x^5 + x^4 + x^2 + x + 1
  */
-const guint32 crc32_ccitt_table[256] = {
+static const guint32 crc32_ccitt_table[256] = {
         0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
         0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
         0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
@@ -193,6 +195,17 @@ crc32c_calculate(const void *buf, int len, guint32 crc)
 	return CRC32C_SWAP(crc);
 }
 
+guint32 
+crc32c_calculate_no_swap(const void *buf, int len, guint32 crc)
+{
+	const guint8 *p = (const guint8 *)buf;
+	while (len-- > 0) {
+		CRC32C(crc, *p++);
+	}
+
+	return crc;
+}
+
 guint32
 crc32_ccitt(const guint8 *buf, guint len)
 {
diff --git a/wsutil/crc32.h b/wsutil/crc32.h
index 514a437596..bb998d1c6e 100644
--- a/wsutil/crc32.h
+++ b/wsutil/crc32.h
@@ -41,14 +41,6 @@ extern "C" {
 	 ((crc32c_value & 0x0000ff00) <<  8)	|	\
 	 ((crc32c_value & 0x000000ff) << 24))
 
-#define CRC32C(c,d) (c=(c>>8)^crc32c_table_lookup((c^(d))&0xFF))
-
-extern const guint32 crc32_ccitt_table[256];
-
-/** Lookup the crc value in the crc32c_table
- @param pos Position in the table. */
-extern guint32 crc32c_table_lookup (guchar pos);
-
 /** Lookup the crc value in the crc32_ccitt_table
  @param pos Position in the table. */
 extern guint32 crc32_ccitt_table_lookup (guchar pos);
@@ -60,6 +52,14 @@ extern guint32 crc32_ccitt_table_lookup (guchar pos);
  @return The CRC32C checksum. */
 extern guint32 crc32c_calculate(const void *buf, int len, guint32 crc);
 
+/** Compute CRC32C checksum of a buffer of data without swapping seed crc
+ or completed checksum
+ @param buf The buffer containing the data.
+ @param len The number of bytes to include in the computation.
+ @param crc The preload value for the CRC32C computation.
+ @return The CRC32C checksum. */
+extern guint32 crc32c_calculate_no_swap(const void *buf, int len, guint32 crc);
+
 /** Compute CRC32 CCITT checksum of a buffer of data.
  @param buf The buffer containing the data.
  @param len The number of bytes to include in the computation.
diff --git a/wsutil/libwsutil.def b/wsutil/libwsutil.def
index 70ef7bb78e..19f2e2b676 100644
--- a/wsutil/libwsutil.def
+++ b/wsutil/libwsutil.def
@@ -30,7 +30,7 @@ crc32_ccitt
 crc32_ccitt_seed
 crc32_ccitt_table_lookup
 crc32c_calculate
-crc32c_table_lookup
+crc32c_calculate_no_swap
 
 ; crcdrm.c
 crc_drm