diff options
Diffstat (limited to 'print-udld.c')
| -rw-r--r-- | print-udld.c | 71 |
1 files changed, 51 insertions, 20 deletions
diff --git a/print-udld.c b/print-udld.c index 15e2bf6f..02921d0e 100644 --- a/print-udld.c +++ b/print-udld.c @@ -12,22 +12,24 @@ * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE. * - * UNIDIRECTIONAL LINK DETECTION (UDLD) as per - * http://www.ietf.org/internet-drafts/draft-foschiano-udld-02.txt - * * Original code by Carles Kishimoto <carles.kishimoto@gmail.com> */ -#define NETDISSECT_REWORKED +/* \summary: Cisco UniDirectional Link Detection (UDLD) protocol printer */ + +/* specification: RFC 5171 */ + #ifdef HAVE_CONFIG_H #include "config.h" #endif -#include <tcpdump-stdinc.h> +#include <netdissect-stdinc.h> -#include "interface.h" +#include "netdissect.h" #include "extract.h" +static const char tstr[] = " [|udld]"; + #define UDLD_HEADER_LEN 4 #define UDLD_DEVICE_ID_TLV 0x0001 #define UDLD_PORT_ID_TLV 0x0002 @@ -63,9 +65,10 @@ static const struct tok udld_flags_values[] = { }; /* + * UDLD's Protocol Data Unit format: * - * 0 1 2 3 - * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + * 0 1 2 3 + * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Ver | Opcode | Flags | Checksum | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ @@ -73,6 +76,18 @@ static const struct tok udld_flags_values[] = { * | ... | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * + * TLV format: + * + * 0 1 2 3 + * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | TYPE | LENGTH | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | VALUE | + * | ... | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * + * LENGTH: Length in bytes of the Type, Length, and Value fields. */ #define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5) @@ -115,35 +130,48 @@ udld_print (netdissect_options *ndo, const u_char *pptr, u_int length) while (tptr < (pptr+length)) { ND_TCHECK2(*tptr, 4); - type = EXTRACT_16BITS(tptr); len = EXTRACT_16BITS(tptr+2); - len -= 4; - tptr += 4; - - /* infinite loop check */ - if (type == 0 || len == 0) { - return; - } ND_PRINT((ndo, "\n\t%s (0x%04x) TLV, length %u", tok2str(udld_tlv_values, "Unknown", type), type, len)); + if (type == 0) + goto invalid; + + /* infinite loop check */ + if (len <= 4) + goto invalid; + + len -= 4; + tptr += 4; + + ND_TCHECK2(*tptr, len); + switch (type) { case UDLD_DEVICE_ID_TLV: case UDLD_PORT_ID_TLV: - case UDLD_ECHO_TLV: case UDLD_DEVICE_NAME_TLV: - ND_PRINT((ndo, ", %s", tptr)); + ND_PRINT((ndo, ", ")); + fn_printzp(ndo, tptr, len, NULL); + break; + + case UDLD_ECHO_TLV: + ND_PRINT((ndo, ", ")); + (void)fn_printn(ndo, tptr, len, NULL); break; case UDLD_MESSAGE_INTERVAL_TLV: case UDLD_TIMEOUT_INTERVAL_TLV: + if (len != 1) + goto invalid; ND_PRINT((ndo, ", %us", (*tptr))); break; case UDLD_SEQ_NUMBER_TLV: + if (len != 4) + goto invalid; ND_PRINT((ndo, ", %u", EXTRACT_32BITS(tptr))); break; @@ -155,8 +183,11 @@ udld_print (netdissect_options *ndo, const u_char *pptr, u_int length) return; - trunc: - ND_PRINT((ndo, "[|udld]")); +invalid: + ND_PRINT((ndo, "%s", istr)); + return; +trunc: + ND_PRINT((ndo, "%s", tstr)); } /* |