diff options
Diffstat (limited to '')
| -rw-r--r-- | print-l2tp.c | 859 |
1 files changed, 859 insertions, 0 deletions
diff --git a/print-l2tp.c b/print-l2tp.c new file mode 100644 index 0000000..895efd2 --- /dev/null +++ b/print-l2tp.c @@ -0,0 +1,859 @@ +/* + * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997 + * The Regents of the University of California. All rights reserved. + * + * 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, (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, and (3) all advertising materials mentioning + * features or use of this software display the following acknowledgement: + * ``This product includes software developed by the University of California, + * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of + * the University nor the names of its contributors may be used to endorse + * or promote products derived from this software without specific prior + * written permission. + * 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. + * + * L2TP support contributed by Motonori Shindo (mshindo@mshindo.net) + */ + +/* \summary: Layer Two Tunneling Protocol (L2TP) printer */ + +/* specification: RFC 2661 */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include "netdissect-stdinc.h" + +#include "netdissect.h" +#include "extract.h" + +#define L2TP_FLAG_TYPE 0x8000 /* Type (0=Data, 1=Control) */ +#define L2TP_FLAG_LENGTH 0x4000 /* Length */ +#define L2TP_FLAG_SEQUENCE 0x0800 /* Sequence */ +#define L2TP_FLAG_OFFSET 0x0200 /* Offset */ +#define L2TP_FLAG_PRIORITY 0x0100 /* Priority */ + +#define L2TP_VERSION_MASK 0x000f /* Version Mask */ +#define L2TP_VERSION_L2F 0x0001 /* L2F */ +#define L2TP_VERSION_L2TP 0x0002 /* L2TP */ + +#define L2TP_AVP_HDR_FLAG_MANDATORY 0x8000 /* Mandatory Flag */ +#define L2TP_AVP_HDR_FLAG_HIDDEN 0x4000 /* Hidden Flag */ +#define L2TP_AVP_HDR_LEN_MASK 0x03ff /* Length Mask */ + +#define L2TP_FRAMING_CAP_SYNC_MASK 0x00000001 /* Synchronous */ +#define L2TP_FRAMING_CAP_ASYNC_MASK 0x00000002 /* Asynchronous */ + +#define L2TP_FRAMING_TYPE_SYNC_MASK 0x00000001 /* Synchronous */ +#define L2TP_FRAMING_TYPE_ASYNC_MASK 0x00000002 /* Asynchronous */ + +#define L2TP_BEARER_CAP_DIGITAL_MASK 0x00000001 /* Digital */ +#define L2TP_BEARER_CAP_ANALOG_MASK 0x00000002 /* Analog */ + +#define L2TP_BEARER_TYPE_DIGITAL_MASK 0x00000001 /* Digital */ +#define L2TP_BEARER_TYPE_ANALOG_MASK 0x00000002 /* Analog */ + +/* Authen Type */ +#define L2TP_AUTHEN_TYPE_RESERVED 0x0000 /* Reserved */ +#define L2TP_AUTHEN_TYPE_TEXTUAL 0x0001 /* Textual username/password exchange */ +#define L2TP_AUTHEN_TYPE_CHAP 0x0002 /* PPP CHAP */ +#define L2TP_AUTHEN_TYPE_PAP 0x0003 /* PPP PAP */ +#define L2TP_AUTHEN_TYPE_NO_AUTH 0x0004 /* No Authentication */ +#define L2TP_AUTHEN_TYPE_MSCHAPv1 0x0005 /* MSCHAPv1 */ + +#define L2TP_PROXY_AUTH_ID_MASK 0x00ff + + +#define L2TP_MSGTYPE_SCCRQ 1 /* Start-Control-Connection-Request */ +#define L2TP_MSGTYPE_SCCRP 2 /* Start-Control-Connection-Reply */ +#define L2TP_MSGTYPE_SCCCN 3 /* Start-Control-Connection-Connected */ +#define L2TP_MSGTYPE_STOPCCN 4 /* Stop-Control-Connection-Notification */ +#define L2TP_MSGTYPE_HELLO 6 /* Hello */ +#define L2TP_MSGTYPE_OCRQ 7 /* Outgoing-Call-Request */ +#define L2TP_MSGTYPE_OCRP 8 /* Outgoing-Call-Reply */ +#define L2TP_MSGTYPE_OCCN 9 /* Outgoing-Call-Connected */ +#define L2TP_MSGTYPE_ICRQ 10 /* Incoming-Call-Request */ +#define L2TP_MSGTYPE_ICRP 11 /* Incoming-Call-Reply */ +#define L2TP_MSGTYPE_ICCN 12 /* Incoming-Call-Connected */ +#define L2TP_MSGTYPE_CDN 14 /* Call-Disconnect-Notify */ +#define L2TP_MSGTYPE_WEN 15 /* WAN-Error-Notify */ +#define L2TP_MSGTYPE_SLI 16 /* Set-Link-Info */ + +static const struct tok l2tp_msgtype2str[] = { + { L2TP_MSGTYPE_SCCRQ, "SCCRQ" }, + { L2TP_MSGTYPE_SCCRP, "SCCRP" }, + { L2TP_MSGTYPE_SCCCN, "SCCCN" }, + { L2TP_MSGTYPE_STOPCCN, "StopCCN" }, + { L2TP_MSGTYPE_HELLO, "HELLO" }, + { L2TP_MSGTYPE_OCRQ, "OCRQ" }, + { L2TP_MSGTYPE_OCRP, "OCRP" }, + { L2TP_MSGTYPE_OCCN, "OCCN" }, + { L2TP_MSGTYPE_ICRQ, "ICRQ" }, + { L2TP_MSGTYPE_ICRP, "ICRP" }, + { L2TP_MSGTYPE_ICCN, "ICCN" }, + { L2TP_MSGTYPE_CDN, "CDN" }, + { L2TP_MSGTYPE_WEN, "WEN" }, + { L2TP_MSGTYPE_SLI, "SLI" }, + { 0, NULL } +}; + +#define L2TP_AVP_MSGTYPE 0 /* Message Type */ +#define L2TP_AVP_RESULT_CODE 1 /* Result Code */ +#define L2TP_AVP_PROTO_VER 2 /* Protocol Version */ +#define L2TP_AVP_FRAMING_CAP 3 /* Framing Capabilities */ +#define L2TP_AVP_BEARER_CAP 4 /* Bearer Capabilities */ +#define L2TP_AVP_TIE_BREAKER 5 /* Tie Breaker */ +#define L2TP_AVP_FIRM_VER 6 /* Firmware Revision */ +#define L2TP_AVP_HOST_NAME 7 /* Host Name */ +#define L2TP_AVP_VENDOR_NAME 8 /* Vendor Name */ +#define L2TP_AVP_ASSND_TUN_ID 9 /* Assigned Tunnel ID */ +#define L2TP_AVP_RECV_WIN_SIZE 10 /* Receive Window Size */ +#define L2TP_AVP_CHALLENGE 11 /* Challenge */ +#define L2TP_AVP_Q931_CC 12 /* Q.931 Cause Code */ +#define L2TP_AVP_CHALLENGE_RESP 13 /* Challenge Response */ +#define L2TP_AVP_ASSND_SESS_ID 14 /* Assigned Session ID */ +#define L2TP_AVP_CALL_SER_NUM 15 /* Call Serial Number */ +#define L2TP_AVP_MINIMUM_BPS 16 /* Minimum BPS */ +#define L2TP_AVP_MAXIMUM_BPS 17 /* Maximum BPS */ +#define L2TP_AVP_BEARER_TYPE 18 /* Bearer Type */ +#define L2TP_AVP_FRAMING_TYPE 19 /* Framing Type */ +#define L2TP_AVP_PACKET_PROC_DELAY 20 /* Packet Processing Delay (OBSOLETE) */ +#define L2TP_AVP_CALLED_NUMBER 21 /* Called Number */ +#define L2TP_AVP_CALLING_NUMBER 22 /* Calling Number */ +#define L2TP_AVP_SUB_ADDRESS 23 /* Sub-Address */ +#define L2TP_AVP_TX_CONN_SPEED 24 /* (Tx) Connect Speed */ +#define L2TP_AVP_PHY_CHANNEL_ID 25 /* Physical Channel ID */ +#define L2TP_AVP_INI_RECV_LCP 26 /* Initial Received LCP CONFREQ */ +#define L2TP_AVP_LAST_SENT_LCP 27 /* Last Sent LCP CONFREQ */ +#define L2TP_AVP_LAST_RECV_LCP 28 /* Last Received LCP CONFREQ */ +#define L2TP_AVP_PROXY_AUTH_TYPE 29 /* Proxy Authen Type */ +#define L2TP_AVP_PROXY_AUTH_NAME 30 /* Proxy Authen Name */ +#define L2TP_AVP_PROXY_AUTH_CHAL 31 /* Proxy Authen Challenge */ +#define L2TP_AVP_PROXY_AUTH_ID 32 /* Proxy Authen ID */ +#define L2TP_AVP_PROXY_AUTH_RESP 33 /* Proxy Authen Response */ +#define L2TP_AVP_CALL_ERRORS 34 /* Call Errors */ +#define L2TP_AVP_ACCM 35 /* ACCM */ +#define L2TP_AVP_RANDOM_VECTOR 36 /* Random Vector */ +#define L2TP_AVP_PRIVATE_GRP_ID 37 /* Private Group ID */ +#define L2TP_AVP_RX_CONN_SPEED 38 /* (Rx) Connect Speed */ +#define L2TP_AVP_SEQ_REQUIRED 39 /* Sequencing Required */ +#define L2TP_AVP_PPP_DISCON_CC 46 /* PPP Disconnect Cause Code - RFC 3145 */ + +static const struct tok l2tp_avp2str[] = { + { L2TP_AVP_MSGTYPE, "MSGTYPE" }, + { L2TP_AVP_RESULT_CODE, "RESULT_CODE" }, + { L2TP_AVP_PROTO_VER, "PROTO_VER" }, + { L2TP_AVP_FRAMING_CAP, "FRAMING_CAP" }, + { L2TP_AVP_BEARER_CAP, "BEARER_CAP" }, + { L2TP_AVP_TIE_BREAKER, "TIE_BREAKER" }, + { L2TP_AVP_FIRM_VER, "FIRM_VER" }, + { L2TP_AVP_HOST_NAME, "HOST_NAME" }, + { L2TP_AVP_VENDOR_NAME, "VENDOR_NAME" }, + { L2TP_AVP_ASSND_TUN_ID, "ASSND_TUN_ID" }, + { L2TP_AVP_RECV_WIN_SIZE, "RECV_WIN_SIZE" }, + { L2TP_AVP_CHALLENGE, "CHALLENGE" }, + { L2TP_AVP_Q931_CC, "Q931_CC", }, + { L2TP_AVP_CHALLENGE_RESP, "CHALLENGE_RESP" }, + { L2TP_AVP_ASSND_SESS_ID, "ASSND_SESS_ID" }, + { L2TP_AVP_CALL_SER_NUM, "CALL_SER_NUM" }, + { L2TP_AVP_MINIMUM_BPS, "MINIMUM_BPS" }, + { L2TP_AVP_MAXIMUM_BPS, "MAXIMUM_BPS" }, + { L2TP_AVP_BEARER_TYPE, "BEARER_TYPE" }, + { L2TP_AVP_FRAMING_TYPE, "FRAMING_TYPE" }, + { L2TP_AVP_PACKET_PROC_DELAY, "PACKET_PROC_DELAY" }, + { L2TP_AVP_CALLED_NUMBER, "CALLED_NUMBER" }, + { L2TP_AVP_CALLING_NUMBER, "CALLING_NUMBER" }, + { L2TP_AVP_SUB_ADDRESS, "SUB_ADDRESS" }, + { L2TP_AVP_TX_CONN_SPEED, "TX_CONN_SPEED" }, + { L2TP_AVP_PHY_CHANNEL_ID, "PHY_CHANNEL_ID" }, + { L2TP_AVP_INI_RECV_LCP, "INI_RECV_LCP" }, + { L2TP_AVP_LAST_SENT_LCP, "LAST_SENT_LCP" }, + { L2TP_AVP_LAST_RECV_LCP, "LAST_RECV_LCP" }, + { L2TP_AVP_PROXY_AUTH_TYPE, "PROXY_AUTH_TYPE" }, + { L2TP_AVP_PROXY_AUTH_NAME, "PROXY_AUTH_NAME" }, + { L2TP_AVP_PROXY_AUTH_CHAL, "PROXY_AUTH_CHAL" }, + { L2TP_AVP_PROXY_AUTH_ID, "PROXY_AUTH_ID" }, + { L2TP_AVP_PROXY_AUTH_RESP, "PROXY_AUTH_RESP" }, + { L2TP_AVP_CALL_ERRORS, "CALL_ERRORS" }, + { L2TP_AVP_ACCM, "ACCM" }, + { L2TP_AVP_RANDOM_VECTOR, "RANDOM_VECTOR" }, + { L2TP_AVP_PRIVATE_GRP_ID, "PRIVATE_GRP_ID" }, + { L2TP_AVP_RX_CONN_SPEED, "RX_CONN_SPEED" }, + { L2TP_AVP_SEQ_REQUIRED, "SEQ_REQUIRED" }, + { L2TP_AVP_PPP_DISCON_CC, "PPP_DISCON_CC" }, + { 0, NULL } +}; + +static const struct tok l2tp_authentype2str[] = { + { L2TP_AUTHEN_TYPE_RESERVED, "Reserved" }, + { L2TP_AUTHEN_TYPE_TEXTUAL, "Textual" }, + { L2TP_AUTHEN_TYPE_CHAP, "CHAP" }, + { L2TP_AUTHEN_TYPE_PAP, "PAP" }, + { L2TP_AUTHEN_TYPE_NO_AUTH, "No Auth" }, + { L2TP_AUTHEN_TYPE_MSCHAPv1, "MS-CHAPv1" }, + { 0, NULL } +}; + +#define L2TP_PPP_DISCON_CC_DIRECTION_GLOBAL 0 +#define L2TP_PPP_DISCON_CC_DIRECTION_AT_PEER 1 +#define L2TP_PPP_DISCON_CC_DIRECTION_AT_LOCAL 2 + +static const struct tok l2tp_cc_direction2str[] = { + { L2TP_PPP_DISCON_CC_DIRECTION_GLOBAL, "global error" }, + { L2TP_PPP_DISCON_CC_DIRECTION_AT_PEER, "at peer" }, + { L2TP_PPP_DISCON_CC_DIRECTION_AT_LOCAL,"at local" }, + { 0, NULL } +}; + +#if 0 +static char *l2tp_result_code_StopCCN[] = { + "Reserved", + "General request to clear control connection", + "General error--Error Code indicates the problem", + "Control channel already exists", + "Requester is not authorized to establish a control channel", + "The protocol version of the requester is not supported", + "Requester is being shut down", + "Finite State Machine error" +#define L2TP_MAX_RESULT_CODE_STOPCC_INDEX 8 +}; +#endif + +#if 0 +static char *l2tp_result_code_CDN[] = { + "Reserved", + "Call disconnected due to loss of carrier", + "Call disconnected for the reason indicated in error code", + "Call disconnected for administrative reasons", + "Call failed due to lack of appropriate facilities being " + "available (temporary condition)", + "Call failed due to lack of appropriate facilities being " + "available (permanent condition)", + "Invalid destination", + "Call failed due to no carrier detected", + "Call failed due to detection of a busy signal", + "Call failed due to lack of a dial tone", + "Call was not established within time allotted by LAC", + "Call was connected but no appropriate framing was detected" +#define L2TP_MAX_RESULT_CODE_CDN_INDEX 12 +}; +#endif + +#if 0 +static char *l2tp_error_code_general[] = { + "No general error", + "No control connection exists yet for this LAC-LNS pair", + "Length is wrong", + "One of the field values was out of range or " + "reserved field was non-zero" + "Insufficient resources to handle this operation now", + "The Session ID is invalid in this context", + "A generic vendor-specific error occurred in the LAC", + "Try another" +#define L2TP_MAX_ERROR_CODE_GENERAL_INDEX 8 +}; +#endif + +/******************************/ +/* generic print out routines */ +/******************************/ +static void +print_string(netdissect_options *ndo, const u_char *dat, u_int length) +{ + u_int i; + for (i=0; i<length; i++) { + fn_print_char(ndo, GET_U_1(dat)); + dat++; + } +} + +static void +print_octets(netdissect_options *ndo, const u_char *dat, u_int length) +{ + u_int i; + for (i=0; i<length; i++) { + ND_PRINT("%02x", GET_U_1(dat)); + dat++; + } +} + +static void +print_16bits_val(netdissect_options *ndo, const uint8_t *dat) +{ + ND_PRINT("%u", GET_BE_U_2(dat)); +} + +static void +print_32bits_val(netdissect_options *ndo, const uint8_t *dat) +{ + ND_PRINT("%u", GET_BE_U_4(dat)); +} + +/***********************************/ +/* AVP-specific print out routines */ +/***********************************/ +static void +l2tp_msgtype_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 2) { + ND_PRINT("AVP too short"); + return; + } + ND_PRINT("%s", tok2str(l2tp_msgtype2str, "MSGTYPE-#%u", + GET_BE_U_2(dat))); +} + +static void +l2tp_result_code_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + /* Result Code */ + if (length < 2) { + ND_PRINT("AVP too short"); + return; + } + ND_PRINT("%u", GET_BE_U_2(dat)); + dat += 2; + length -= 2; + + /* Error Code (opt) */ + if (length == 0) + return; + if (length < 2) { + ND_PRINT(" AVP too short"); + return; + } + ND_PRINT("/%u", GET_BE_U_2(dat)); + dat += 2; + length -= 2; + + /* Error Message (opt) */ + if (length == 0) + return; + ND_PRINT(" "); + print_string(ndo, dat, length); +} + +static void +l2tp_proto_ver_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 2) { + ND_PRINT("AVP too short"); + return; + } + ND_PRINT("%u.%u", (GET_BE_U_2(dat) >> 8), + (GET_BE_U_2(dat) & 0xff)); +} + +static void +l2tp_framing_cap_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + if (GET_BE_U_4(dat) & L2TP_FRAMING_CAP_ASYNC_MASK) { + ND_PRINT("A"); + } + if (GET_BE_U_4(dat) & L2TP_FRAMING_CAP_SYNC_MASK) { + ND_PRINT("S"); + } +} + +static void +l2tp_bearer_cap_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + if (GET_BE_U_4(dat) & L2TP_BEARER_CAP_ANALOG_MASK) { + ND_PRINT("A"); + } + if (GET_BE_U_4(dat) & L2TP_BEARER_CAP_DIGITAL_MASK) { + ND_PRINT("D"); + } +} + +static void +l2tp_q931_cc_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 3) { + ND_PRINT("AVP too short"); + return; + } + print_16bits_val(ndo, dat); + ND_PRINT(", %02x", GET_U_1(dat + 2)); + dat += 3; + length -= 3; + if (length != 0) { + ND_PRINT(" "); + print_string(ndo, dat, length); + } +} + +static void +l2tp_bearer_type_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + if (GET_BE_U_4(dat) & L2TP_BEARER_TYPE_ANALOG_MASK) { + ND_PRINT("A"); + } + if (GET_BE_U_4(dat) & L2TP_BEARER_TYPE_DIGITAL_MASK) { + ND_PRINT("D"); + } +} + +static void +l2tp_framing_type_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + if (GET_BE_U_4(dat) & L2TP_FRAMING_TYPE_ASYNC_MASK) { + ND_PRINT("A"); + } + if (GET_BE_U_4(dat) & L2TP_FRAMING_TYPE_SYNC_MASK) { + ND_PRINT("S"); + } +} + +static void +l2tp_packet_proc_delay_print(netdissect_options *ndo) +{ + ND_PRINT("obsolete"); +} + +static void +l2tp_proxy_auth_type_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 2) { + ND_PRINT("AVP too short"); + return; + } + ND_PRINT("%s", tok2str(l2tp_authentype2str, + "AuthType-#%u", GET_BE_U_2(dat))); +} + +static void +l2tp_proxy_auth_id_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 2) { + ND_PRINT("AVP too short"); + return; + } + ND_PRINT("%u", GET_BE_U_2(dat) & L2TP_PROXY_AUTH_ID_MASK); +} + +static void +l2tp_call_errors_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + uint32_t val; + + if (length < 2) { + ND_PRINT("AVP too short"); + return; + } + dat += 2; /* skip "Reserved" */ + length -= 2; + + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + val = GET_BE_U_4(dat); dat += 4; length -= 4; + ND_PRINT("CRCErr=%u ", val); + + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + val = GET_BE_U_4(dat); dat += 4; length -= 4; + ND_PRINT("FrameErr=%u ", val); + + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + val = GET_BE_U_4(dat); dat += 4; length -= 4; + ND_PRINT("HardOver=%u ", val); + + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + val = GET_BE_U_4(dat); dat += 4; length -= 4; + ND_PRINT("BufOver=%u ", val); + + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + val = GET_BE_U_4(dat); dat += 4; length -= 4; + ND_PRINT("Timeout=%u ", val); + + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + val = GET_BE_U_4(dat); dat += 4; length -= 4; + ND_PRINT("AlignErr=%u ", val); +} + +static void +l2tp_accm_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + uint32_t val; + + if (length < 2) { + ND_PRINT("AVP too short"); + return; + } + dat += 2; /* skip "Reserved" */ + length -= 2; + + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + val = GET_BE_U_4(dat); dat += 4; length -= 4; + ND_PRINT("send=%08x ", val); + + if (length < 4) { + ND_PRINT("AVP too short"); + return; + } + val = GET_BE_U_4(dat); dat += 4; length -= 4; + ND_PRINT("recv=%08x ", val); +} + +static void +l2tp_ppp_discon_cc_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + if (length < 5) { + ND_PRINT("AVP too short"); + return; + } + /* Disconnect Code */ + ND_PRINT("%04x, ", GET_BE_U_2(dat)); + dat += 2; + length -= 2; + /* Control Protocol Number */ + ND_PRINT("%04x ", GET_BE_U_2(dat)); + dat += 2; + length -= 2; + /* Direction */ + ND_PRINT("%s", tok2str(l2tp_cc_direction2str, + "Direction-#%u", GET_U_1(dat))); + dat++; + length--; + + if (length != 0) { + ND_PRINT(" "); + print_string(ndo, (const u_char *)dat, length); + } +} + +static u_int +l2tp_avp_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + u_int len; + uint16_t attr_type; + int hidden = FALSE; + + ND_PRINT(" "); + /* Flags & Length */ + len = GET_BE_U_2(dat) & L2TP_AVP_HDR_LEN_MASK; + + /* If it is not long enough to contain the header, we'll give up. */ + if (len < 6) + goto trunc; + + /* If it goes past the end of the remaining length of the packet, + we'll give up. */ + if (len > (u_int)length) + goto trunc; + + /* If it goes past the end of the remaining length of the captured + data, we'll give up. */ + ND_TCHECK_LEN(dat, len); + + /* + * After this point, we don't need to check whether we go past + * the length of the captured data; however, we *do* need to + * check whether we go past the end of the AVP. + */ + + if (GET_BE_U_2(dat) & L2TP_AVP_HDR_FLAG_MANDATORY) { + ND_PRINT("*"); + } + if (GET_BE_U_2(dat) & L2TP_AVP_HDR_FLAG_HIDDEN) { + hidden = TRUE; + ND_PRINT("?"); + } + dat += 2; + + if (GET_BE_U_2(dat)) { + /* Vendor Specific Attribute */ + ND_PRINT("VENDOR%04x:", GET_BE_U_2(dat)); dat += 2; + ND_PRINT("ATTR%04x", GET_BE_U_2(dat)); dat += 2; + ND_PRINT("("); + print_octets(ndo, dat, len-6); + ND_PRINT(")"); + } else { + /* IETF-defined Attributes */ + dat += 2; + attr_type = GET_BE_U_2(dat); dat += 2; + ND_PRINT("%s", tok2str(l2tp_avp2str, "AVP-#%u", attr_type)); + ND_PRINT("("); + if (hidden) { + ND_PRINT("???"); + } else { + switch (attr_type) { + case L2TP_AVP_MSGTYPE: + l2tp_msgtype_print(ndo, dat, len-6); + break; + case L2TP_AVP_RESULT_CODE: + l2tp_result_code_print(ndo, dat, len-6); + break; + case L2TP_AVP_PROTO_VER: + l2tp_proto_ver_print(ndo, dat, len-6); + break; + case L2TP_AVP_FRAMING_CAP: + l2tp_framing_cap_print(ndo, dat, len-6); + break; + case L2TP_AVP_BEARER_CAP: + l2tp_bearer_cap_print(ndo, dat, len-6); + break; + case L2TP_AVP_TIE_BREAKER: + if (len-6 < 8) { + ND_PRINT("AVP too short"); + break; + } + print_octets(ndo, dat, 8); + break; + case L2TP_AVP_FIRM_VER: + case L2TP_AVP_ASSND_TUN_ID: + case L2TP_AVP_RECV_WIN_SIZE: + case L2TP_AVP_ASSND_SESS_ID: + if (len-6 < 2) { + ND_PRINT("AVP too short"); + break; + } + print_16bits_val(ndo, dat); + break; + case L2TP_AVP_HOST_NAME: + case L2TP_AVP_VENDOR_NAME: + case L2TP_AVP_CALLING_NUMBER: + case L2TP_AVP_CALLED_NUMBER: + case L2TP_AVP_SUB_ADDRESS: + case L2TP_AVP_PROXY_AUTH_NAME: + case L2TP_AVP_PRIVATE_GRP_ID: + print_string(ndo, dat, len-6); + break; + case L2TP_AVP_CHALLENGE: + case L2TP_AVP_INI_RECV_LCP: + case L2TP_AVP_LAST_SENT_LCP: + case L2TP_AVP_LAST_RECV_LCP: + case L2TP_AVP_PROXY_AUTH_CHAL: + case L2TP_AVP_PROXY_AUTH_RESP: + case L2TP_AVP_RANDOM_VECTOR: + print_octets(ndo, dat, len-6); + break; + case L2TP_AVP_Q931_CC: + l2tp_q931_cc_print(ndo, dat, len-6); + break; + case L2TP_AVP_CHALLENGE_RESP: + if (len-6 < 16) { + ND_PRINT("AVP too short"); + break; + } + print_octets(ndo, dat, 16); + break; + case L2TP_AVP_CALL_SER_NUM: + case L2TP_AVP_MINIMUM_BPS: + case L2TP_AVP_MAXIMUM_BPS: + case L2TP_AVP_TX_CONN_SPEED: + case L2TP_AVP_PHY_CHANNEL_ID: + case L2TP_AVP_RX_CONN_SPEED: + if (len-6 < 4) { + ND_PRINT("AVP too short"); + break; + } + print_32bits_val(ndo, dat); + break; + case L2TP_AVP_BEARER_TYPE: + l2tp_bearer_type_print(ndo, dat, len-6); + break; + case L2TP_AVP_FRAMING_TYPE: + l2tp_framing_type_print(ndo, dat, len-6); + break; + case L2TP_AVP_PACKET_PROC_DELAY: + l2tp_packet_proc_delay_print(ndo); + break; + case L2TP_AVP_PROXY_AUTH_TYPE: + l2tp_proxy_auth_type_print(ndo, dat, len-6); + break; + case L2TP_AVP_PROXY_AUTH_ID: + l2tp_proxy_auth_id_print(ndo, dat, len-6); + break; + case L2TP_AVP_CALL_ERRORS: + l2tp_call_errors_print(ndo, dat, len-6); + break; + case L2TP_AVP_ACCM: + l2tp_accm_print(ndo, dat, len-6); + break; + case L2TP_AVP_SEQ_REQUIRED: + break; /* No Attribute Value */ + case L2TP_AVP_PPP_DISCON_CC: + l2tp_ppp_discon_cc_print(ndo, dat, len-6); + break; + default: + break; + } + } + ND_PRINT(")"); + } + + return (len); + + trunc: + nd_print_trunc(ndo); + return (0); +} + + +void +l2tp_print(netdissect_options *ndo, const u_char *dat, u_int length) +{ + const u_char *ptr = dat; + u_int cnt = 0; /* total octets consumed */ + uint16_t pad; + int flag_t, flag_l, flag_s, flag_o; + uint16_t l2tp_len; + + ndo->ndo_protocol = "l2tp"; + flag_t = flag_l = flag_s = flag_o = FALSE; + + if ((GET_BE_U_2(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2TP) { + ND_PRINT(" l2tp:"); + } else if ((GET_BE_U_2(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2F) { + ND_PRINT(" l2f:"); + return; /* nothing to do */ + } else { + ND_PRINT(" Unknown Version, neither L2F(1) nor L2TP(2)"); + return; /* nothing we can do */ + } + + ND_PRINT("["); + if (GET_BE_U_2(ptr) & L2TP_FLAG_TYPE) { + flag_t = TRUE; + ND_PRINT("T"); + } + if (GET_BE_U_2(ptr) & L2TP_FLAG_LENGTH) { + flag_l = TRUE; + ND_PRINT("L"); + } + if (GET_BE_U_2(ptr) & L2TP_FLAG_SEQUENCE) { + flag_s = TRUE; + ND_PRINT("S"); + } + if (GET_BE_U_2(ptr) & L2TP_FLAG_OFFSET) { + flag_o = TRUE; + ND_PRINT("O"); + } + if (GET_BE_U_2(ptr) & L2TP_FLAG_PRIORITY) + ND_PRINT("P"); + ND_PRINT("]"); + + ptr += 2; + cnt += 2; + + if (flag_l) { + l2tp_len = GET_BE_U_2(ptr); + ptr += 2; + cnt += 2; + } else { + l2tp_len = 0; + } + /* Tunnel ID */ + ND_PRINT("(%u/", GET_BE_U_2(ptr)); + ptr += 2; + cnt += 2; + /* Session ID */ + ND_PRINT("%u)", GET_BE_U_2(ptr)); + ptr += 2; + cnt += 2; + + if (flag_s) { + ND_PRINT("Ns=%u,", GET_BE_U_2(ptr)); + ptr += 2; + cnt += 2; + ND_PRINT("Nr=%u", GET_BE_U_2(ptr)); + ptr += 2; + cnt += 2; + } + + if (flag_o) { /* Offset Size */ + pad = GET_BE_U_2(ptr); + /* Offset padding octets in packet buffer? */ + ND_TCHECK_LEN(ptr + 2, pad); + ptr += (2 + pad); + cnt += (2 + pad); + } + + if (flag_l) { + if (length < l2tp_len) { + ND_PRINT(" Length %u larger than packet", l2tp_len); + return; + } + length = l2tp_len; + } + if (length < cnt) { + ND_PRINT(" Length %u smaller than header length", length); + return; + } + if (flag_t) { + if (!flag_l) { + ND_PRINT(" No length"); + return; + } + if (length - cnt == 0) { + ND_PRINT(" ZLB"); + } else { + /* + * Print AVPs. + */ + while (length - cnt != 0) { + u_int avp_length; + + avp_length = l2tp_avp_print(ndo, ptr, length - cnt); + if (avp_length == 0) { + /* + * Truncated. + */ + break; + } + cnt += avp_length; + ptr += avp_length; + } + } + } else { + ND_PRINT(" {"); + ppp_print(ndo, ptr, length - cnt); + ND_PRINT("}"); + } + return; +trunc: + nd_print_trunc(ndo); +} |