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| author | Guy Harris <guy@alum.mit.edu> | 2014-08-15 15:38:31 -0700 |
|---|---|---|
| committer | Guy Harris <guy@alum.mit.edu> | 2014-08-15 15:38:31 -0700 |
| commit | 6ab3136df5500b48a93619019658b14ee562666c (patch) | |
| tree | 565000206c491353fb239c2b71c904cc6ec39ff8 /print-cdp.c | |
| parent | e9ed7f5dc980b1aaa691e19113fd2e0a7857348a (diff) | |
| download | tcpdump-6ab3136df5500b48a93619019658b14ee562666c.tar.gz | |
More #defines for CDP lengths and offsets.
Diffstat (limited to 'print-cdp.c')
| -rw-r--r-- | print-cdp.c | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/print-cdp.c b/print-cdp.c index a5aeecde..aefb68db 100644 --- 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); |