/* * 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) */ #ifndef lint static const char rcsid[] _U_ = "@(#) $Header: /tcpdump/master/tcpdump/print-l2tp.c,v 1.17.2.2 2005/04/20 21:50:16 guy Exp $"; #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include "l2tp.h" #include "interface.h" #include "extract.h" static char tstr[] = " [|l2tp]"; #ifndef TRUE #define TRUE 1 #endif #ifndef FALSE #define FALSE 0 #endif #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 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 */ static 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 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 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(const u_char *dat, u_int length) { u_int i; for (i=0; i 2) { /* Error Code (opt) */ printf("/%u", EXTRACT_16BITS(ptr)); ptr++; } if (length > 4) { /* Error Message (opt) */ printf(" "); print_string((u_char *)ptr, length - 4); } } static void l2tp_proto_ver_print(const u_int16_t *dat) { printf("%u.%u", (EXTRACT_16BITS(dat) >> 8), (EXTRACT_16BITS(dat) & 0xff)); } static void l2tp_framing_cap_print(const u_char *dat) { u_int32_t *ptr = (u_int32_t *)dat; if (EXTRACT_32BITS(ptr) & L2TP_FRAMING_CAP_ASYNC_MASK) { printf("A"); } if (EXTRACT_32BITS(ptr) & L2TP_FRAMING_CAP_SYNC_MASK) { printf("S"); } } static void l2tp_bearer_cap_print(const u_char *dat) { u_int32_t *ptr = (u_int32_t *)dat; if (EXTRACT_32BITS(ptr) & L2TP_BEARER_CAP_ANALOG_MASK) { printf("A"); } if (EXTRACT_32BITS(ptr) & L2TP_BEARER_CAP_DIGITAL_MASK) { printf("D"); } } static void l2tp_q931_cc_print(const u_char *dat, u_int length) { print_16bits_val((u_int16_t *)dat); printf(", %02x", dat[2]); if (length > 3) { printf(" "); print_string(dat+3, length-3); } } static void l2tp_bearer_type_print(const u_char *dat) { u_int32_t *ptr = (u_int32_t *)dat; if (EXTRACT_32BITS(ptr) & L2TP_BEARER_TYPE_ANALOG_MASK) { printf("A"); } if (EXTRACT_32BITS(ptr) & L2TP_BEARER_TYPE_DIGITAL_MASK) { printf("D"); } } static void l2tp_framing_type_print(const u_char *dat) { u_int32_t *ptr = (u_int32_t *)dat; if (EXTRACT_32BITS(ptr) & L2TP_FRAMING_TYPE_ASYNC_MASK) { printf("A"); } if (EXTRACT_32BITS(ptr) & L2TP_FRAMING_TYPE_SYNC_MASK) { printf("S"); } } static void l2tp_packet_proc_delay_print(void) { printf("obsolete"); } static void l2tp_proxy_auth_type_print(const u_char *dat) { u_int16_t *ptr = (u_int16_t *)dat; printf("%s", tok2str(l2tp_authentype2str, "AuthType-#%u", EXTRACT_16BITS(ptr))); } static void l2tp_proxy_auth_id_print(const u_char *dat) { u_int16_t *ptr = (u_int16_t *)dat; printf("%u", EXTRACT_16BITS(ptr) & L2TP_PROXY_AUTH_ID_MASK); } static void l2tp_call_errors_print(const u_char *dat) { u_int16_t *ptr = (u_int16_t *)dat; u_int16_t val_h, val_l; ptr++; /* skip "Reserved" */ val_h = EXTRACT_16BITS(ptr); ptr++; val_l = EXTRACT_16BITS(ptr); ptr++; printf("CRCErr=%u ", (val_h<<16) + val_l); val_h = EXTRACT_16BITS(ptr); ptr++; val_l = EXTRACT_16BITS(ptr); ptr++; printf("FrameErr=%u ", (val_h<<16) + val_l); val_h = EXTRACT_16BITS(ptr); ptr++; val_l = EXTRACT_16BITS(ptr); ptr++; printf("HardOver=%u ", (val_h<<16) + val_l); val_h = EXTRACT_16BITS(ptr); ptr++; val_l = EXTRACT_16BITS(ptr); ptr++; printf("BufOver=%u ", (val_h<<16) + val_l); val_h = EXTRACT_16BITS(ptr); ptr++; val_l = EXTRACT_16BITS(ptr); ptr++; printf("Timeout=%u ", (val_h<<16) + val_l); val_h = EXTRACT_16BITS(ptr); ptr++; val_l = EXTRACT_16BITS(ptr); ptr++; printf("AlignErr=%u ", (val_h<<16) + val_l); } static void l2tp_accm_print(const u_char *dat) { u_int16_t *ptr = (u_int16_t *)dat; u_int16_t val_h, val_l; ptr++; /* skip "Reserved" */ val_h = EXTRACT_16BITS(ptr); ptr++; val_l = EXTRACT_16BITS(ptr); ptr++; printf("send=%08x ", (val_h<<16) + val_l); val_h = EXTRACT_16BITS(ptr); ptr++; val_l = EXTRACT_16BITS(ptr); ptr++; printf("recv=%08x ", (val_h<<16) + val_l); } static void l2tp_ppp_discon_cc_print(const u_char *dat, u_int length) { u_int16_t *ptr = (u_int16_t *)dat; printf("%04x, ", EXTRACT_16BITS(ptr)); ptr++; /* Disconnect Code */ printf("%04x ", EXTRACT_16BITS(ptr)); ptr++; /* Control Protocol Number */ printf("%s", tok2str(l2tp_cc_direction2str, "Direction-#%u", *((u_char *)ptr++))); if (length > 5) { printf(" "); print_string((const u_char *)ptr, length-5); } } static void l2tp_avp_print(const u_char *dat, int length) { u_int len; const u_int16_t *ptr = (u_int16_t *)dat; u_int16_t attr_type; int hidden = FALSE; if (length <= 0) { return; } printf(" "); TCHECK(*ptr); /* Flags & Length */ len = EXTRACT_16BITS(ptr) & 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. */ TCHECK2(*ptr, len); /* After this point, no need to worry about truncation */ if (EXTRACT_16BITS(ptr) & L2TP_AVP_HDR_FLAG_MANDATORY) { printf("*"); } if (EXTRACT_16BITS(ptr) & L2TP_AVP_HDR_FLAG_HIDDEN) { hidden = TRUE; printf("?"); } ptr++; if (EXTRACT_16BITS(ptr)) { /* Vendor Specific Attribute */ printf("VENDOR%04x:", EXTRACT_16BITS(ptr)); ptr++; printf("ATTR%04x", EXTRACT_16BITS(ptr)); ptr++; printf("("); print_octets((u_char *)ptr, len-6); printf(")"); } else { /* IETF-defined Attributes */ ptr++; attr_type = EXTRACT_16BITS(ptr); ptr++; printf("%s", tok2str(l2tp_avp2str, "AVP-#%u", attr_type)); printf("("); if (hidden) { printf("???"); } else { switch (attr_type) { case L2TP_AVP_MSGTYPE: l2tp_msgtype_print((u_char *)ptr); break; case L2TP_AVP_RESULT_CODE: l2tp_result_code_print((u_char *)ptr, len-6); break; case L2TP_AVP_PROTO_VER: l2tp_proto_ver_print(ptr); break; case L2TP_AVP_FRAMING_CAP: l2tp_framing_cap_print((u_char *)ptr); break; case L2TP_AVP_BEARER_CAP: l2tp_bearer_cap_print((u_char *)ptr); break; case L2TP_AVP_TIE_BREAKER: print_octets((u_char *)ptr, 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: print_16bits_val(ptr); 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((u_char *)ptr, 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((u_char *)ptr, len-6); break; case L2TP_AVP_Q931_CC: l2tp_q931_cc_print((u_char *)ptr, len-6); break; case L2TP_AVP_CHALLENGE_RESP: print_octets((u_char *)ptr, 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: print_32bits_val((u_int32_t *)ptr); break; case L2TP_AVP_BEARER_TYPE: l2tp_bearer_type_print((u_char *)ptr); break; case L2TP_AVP_FRAMING_TYPE: l2tp_framing_type_print((u_char *)ptr); break; case L2TP_AVP_PACKET_PROC_DELAY: l2tp_packet_proc_delay_print(); break; case L2TP_AVP_PROXY_AUTH_TYPE: l2tp_proxy_auth_type_print((u_char *)ptr); break; case L2TP_AVP_PROXY_AUTH_ID: l2tp_proxy_auth_id_print((u_char *)ptr); break; case L2TP_AVP_CALL_ERRORS: l2tp_call_errors_print((u_char *)ptr); break; case L2TP_AVP_ACCM: l2tp_accm_print((u_char *)ptr); break; case L2TP_AVP_SEQ_REQUIRED: break; /* No Attribute Value */ case L2TP_AVP_PPP_DISCON_CC: l2tp_ppp_discon_cc_print((u_char *)ptr, len-6); break; default: break; } } printf(")"); } l2tp_avp_print(dat+len, length-len); return; trunc: printf("|..."); } void l2tp_print(const u_char *dat, u_int length) { const u_int16_t *ptr = (u_int16_t *)dat; u_int cnt = 0; /* total octets consumed */ u_int16_t pad; int flag_t, flag_l, flag_s, flag_o; u_int16_t l2tp_len; flag_t = flag_l = flag_s = flag_o = FALSE; TCHECK(*ptr); /* Flags & Version */ if ((EXTRACT_16BITS(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2TP) { printf(" l2tp:"); } else if ((EXTRACT_16BITS(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2F) { printf(" l2f:"); return; /* nothing to do */ } else { printf(" Unknown Version, neither L2F(1) nor L2TP(2)"); return; /* nothing we can do */ } printf("["); if (EXTRACT_16BITS(ptr) & L2TP_FLAG_TYPE) { flag_t = TRUE; printf("T"); } if (EXTRACT_16BITS(ptr) & L2TP_FLAG_LENGTH) { flag_l = TRUE; printf("L"); } if (EXTRACT_16BITS(ptr) & L2TP_FLAG_SEQUENCE) { flag_s = TRUE; printf("S"); } if (EXTRACT_16BITS(ptr) & L2TP_FLAG_OFFSET) { flag_o = TRUE; printf("O"); } if (EXTRACT_16BITS(ptr) & L2TP_FLAG_PRIORITY) printf("P"); printf("]"); ptr++; cnt += 2; if (flag_l) { TCHECK(*ptr); /* Length */ l2tp_len = EXTRACT_16BITS(ptr); ptr++; cnt += 2; } else { l2tp_len = 0; } TCHECK(*ptr); /* Tunnel ID */ printf("(%u/", EXTRACT_16BITS(ptr)); ptr++; cnt += 2; TCHECK(*ptr); /* Session ID */ printf("%u)", EXTRACT_16BITS(ptr)); ptr++; cnt += 2; if (flag_s) { TCHECK(*ptr); /* Ns */ printf("Ns=%u,", EXTRACT_16BITS(ptr)); ptr++; cnt += 2; TCHECK(*ptr); /* Nr */ printf("Nr=%u", EXTRACT_16BITS(ptr)); ptr++; cnt += 2; } if (flag_o) { TCHECK(*ptr); /* Offset Size */ pad = EXTRACT_16BITS(ptr); ptr++; ptr += pad / sizeof(*ptr); cnt += (2 + pad); } if (flag_l) { if (length < l2tp_len) { printf(" Length %u larger than packet", l2tp_len); return; } length = l2tp_len; } if (length < cnt) { printf(" Length %u smaller than header length", length); return; } if (flag_t) { if (!flag_l) { printf(" No length"); return; } if (length - cnt == 0) { printf(" ZLB"); } else { l2tp_avp_print((u_char *)ptr, length - cnt); } } else { printf(" {"); ppp_print((u_char *)ptr, length - cnt); printf("}"); } return; trunc: printf("%s", tstr); }