diff options
Diffstat (limited to 'print-udld.c')
| -rw-r--r-- | print-udld.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/print-udld.c b/print-udld.c new file mode 100644 index 0000000..aec1d9e --- /dev/null +++ b/print-udld.c @@ -0,0 +1,207 @@ +/* + * Copyright (c) 1998-2007 The TCPDUMP project + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that: (1) source code + * distributions retain the above copyright notice and this paragraph + * in its entirety, and (2) distributions including binary code include + * the above copyright notice and this paragraph in its entirety in + * the documentation or other materials provided with the distribution. + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND + * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT + * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE. + * + * Original code by Carles Kishimoto <carles.kishimoto@gmail.com> + */ + +/* \summary: Cisco UniDirectional Link Detection (UDLD) protocol printer */ + +/* specification: RFC 5171 */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include "netdissect-stdinc.h" + +#define ND_LONGJMP_FROM_TCHECK +#include "netdissect.h" +#include "extract.h" + + +#define UDLD_HEADER_LEN 4 +#define UDLD_TLV_HEADER_LEN 4 +#define UDLD_DEVICE_ID_TLV 0x0001 +#define UDLD_PORT_ID_TLV 0x0002 +#define UDLD_ECHO_TLV 0x0003 +#define UDLD_MESSAGE_INTERVAL_TLV 0x0004 +#define UDLD_TIMEOUT_INTERVAL_TLV 0x0005 +#define UDLD_DEVICE_NAME_TLV 0x0006 +#define UDLD_SEQ_NUMBER_TLV 0x0007 + +static const struct tok udld_tlv_values[] = { + { UDLD_DEVICE_ID_TLV, "Device-ID TLV"}, + { UDLD_PORT_ID_TLV, "Port-ID TLV"}, + { UDLD_ECHO_TLV, "Echo TLV"}, + { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"}, + { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"}, + { UDLD_DEVICE_NAME_TLV, "Device Name TLV"}, + { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"}, + { 0, NULL} +}; + +static const struct tok udld_code_values[] = { + { 0x00, "Reserved"}, + { 0x01, "Probe message"}, + { 0x02, "Echo message"}, + { 0x03, "Flush message"}, + { 0, NULL} +}; + +static const struct tok udld_flags_bitmap_str[] = { + { 1U << 0, "RT" }, + { 1U << 1, "RSY" }, + { 1U << 2, "MBZ-2" }, + { 1U << 3, "MBZ-3" }, + { 1U << 4, "MBZ-4" }, + { 1U << 5, "MBZ-5" }, + { 1U << 6, "MBZ-6" }, + { 1U << 7, "MBZ-7" }, + { 0, NULL} +}; + +/* + * 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 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | Ver | Opcode | Flags | Checksum | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | List of TLVs (variable length list) | + * | ... | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * + * 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) +#define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f) + +void +udld_print(netdissect_options *ndo, + const u_char *tptr, u_int length) +{ + uint8_t ver, code, flags; + + ndo->ndo_protocol = "udld"; + if (length < UDLD_HEADER_LEN) + goto invalid; + + ver = UDLD_EXTRACT_VERSION(GET_U_1(tptr)); + code = UDLD_EXTRACT_OPCODE(GET_U_1(tptr)); + tptr += 1; + length -= 1; + + flags = GET_U_1(tptr); + tptr += 1; + length -= 1; + + ND_PRINT("UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u", + ver, + tok2str(udld_code_values, "Reserved", code), + code, + bittok2str(udld_flags_bitmap_str, "none", flags), + flags, + length + 2); + + /* + * In non-verbose mode, just print version and opcode type + */ + if (ndo->ndo_vflag < 1) { + goto tcheck_remainder; + } + + ND_PRINT("\n\tChecksum 0x%04x (unverified)", GET_BE_U_2(tptr)); + tptr += 2; + length -= 2; + + while (length) { + uint16_t type, len; + + if (length < UDLD_TLV_HEADER_LEN) + goto invalid; + + type = GET_BE_U_2(tptr); + tptr += 2; + length -= 2; + + len = GET_BE_U_2(tptr); + tptr += 2; + length -= 2; + + ND_PRINT("\n\t%s (0x%04x) TLV, length %u", + tok2str(udld_tlv_values, "Unknown", type), + type, len); + + /* infinite loop check */ + if (len <= UDLD_TLV_HEADER_LEN) + goto invalid; + + len -= UDLD_TLV_HEADER_LEN; + if (length < len) + goto invalid; + + switch (type) { + case UDLD_DEVICE_ID_TLV: + case UDLD_PORT_ID_TLV: + case UDLD_DEVICE_NAME_TLV: + ND_PRINT(", "); + nd_printjnp(ndo, tptr, len); + break; + + case UDLD_ECHO_TLV: + ND_PRINT(", "); + (void)nd_printn(ndo, tptr, len, NULL); + break; + + case UDLD_MESSAGE_INTERVAL_TLV: + case UDLD_TIMEOUT_INTERVAL_TLV: + if (len != 1) + goto invalid; + ND_PRINT(", %us", (GET_U_1(tptr))); + break; + + case UDLD_SEQ_NUMBER_TLV: + if (len != 4) + goto invalid; + ND_PRINT(", %u", GET_BE_U_4(tptr)); + break; + + default: + ND_TCHECK_LEN(tptr, len); + break; + } + tptr += len; + length -= len; + } + + return; + +invalid: + nd_print_invalid(ndo); +tcheck_remainder: + ND_TCHECK_LEN(tptr, length); +} |