More #defines for CDP lengths and offsets.

diff --git a/print-cdp.c b/print-cdp.c
index a5aeecded7502b021a560ef5e3a7a39fb87eb2e9..aefb68dbcf751eaef7aa96c44dee8e3ce3f41bd7 100644 (file)
--- a/print-cdp.c
+++ b/print-cdp.c
@@ -40,8 +40,14 @@
 
 static const char tstr[] = "[|cdp]";
 
-#define CDP_HEADER_LEN     4
-#define CDP_HEADER_OFFSET  2
+#define CDP_HEADER_LEN             4
+#define CDP_HEADER_VERSION_OFFSET  0
+#define CDP_HEADER_TTL_OFFSET      1
+#define CDP_HEADER_CHECKSUM_OFFSET 2
+
+#define CDP_TLV_HEADER_LEN  4
+#define CDP_TLV_TYPE_OFFSET 0
+#define CDP_TLV_LEN_OFFSET  2
 
 static const struct tok cdp_tlv_values[] = {
     { 0x01,             "Device-ID"},
@@ -98,16 +104,17 @@ cdp_print(netdissect_options *ndo,
        tptr = pptr; /* temporary pointer */
 
        ND_TCHECK2(*tptr, CDP_HEADER_LEN);
-       ND_PRINT((ndo, "CDPv%u, ttl: %us", *tptr, *(tptr + 1)));
+       ND_PRINT((ndo, "CDPv%u, ttl: %us", *(tptr + CDP_HEADER_VERSION_OFFSET),
+                                          *(tptr + CDP_HEADER_TTL_OFFSET)));
        if (ndo->ndo_vflag)
-               ND_PRINT((ndo, ", checksum: 0x%04x (unverified), length %u", EXTRACT_16BITS(tptr+CDP_HEADER_OFFSET), length));
+               ND_PRINT((ndo, ", checksum: 0x%04x (unverified), length %u", EXTRACT_16BITS(tptr+CDP_HEADER_CHECKSUM_OFFSET), length));
        tptr += CDP_HEADER_LEN;
 
        while (tptr < (pptr+length)) {
-               ND_TCHECK2(*tptr, CDP_HEADER_LEN); /* read out Type and Length */
-               type = EXTRACT_16BITS(tptr);
-               len  = EXTRACT_16BITS(tptr+CDP_HEADER_OFFSET); /* object length includes the 4 bytes header length */
-               if (len < CDP_HEADER_LEN) {
+               ND_TCHECK2(*tptr, CDP_TLV_HEADER_LEN); /* read out Type and Length */
+               type = EXTRACT_16BITS(tptr+CDP_TLV_TYPE_OFFSET);
+               len  = EXTRACT_16BITS(tptr+CDP_TLV_LEN_OFFSET); /* object length includes the 4 bytes header length */
+               if (len < CDP_TLV_HEADER_LEN) {
                    if (ndo->ndo_vflag)
                        ND_PRINT((ndo, "\n\t%s (0x%02x), TLV length: %u byte%s (too short)",
                               tok2str(cdp_tlv_values,"unknown field type", type),
@@ -120,8 +127,8 @@ cdp_print(netdissect_options *ndo,
                               len));
                    break;
                }
-               tptr += CDP_HEADER_LEN;
-               len -= CDP_HEADER_LEN;
+               tptr += CDP_TLV_HEADER_LEN;
+               len -= CDP_TLV_HEADER_LEN;
 
                ND_TCHECK2(*tptr, len);