text: /*
   * Copyright (c) 2013 The TCPDUMP project
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  /* \summary: Ad Hoc Configuration Protocol (AHCP) printer */
  
  /* Based on draft-chroboczek-ahcp-00 and source code of ahcpd-0.53 */
  
  #ifdef HAVE_CONFIG_H
  #include <config.h>
  #endif
  
  #include "netdissect-stdinc.h"
  
  #include "netdissect.h"
  #include "extract.h"
  #include "addrtoname.h"
  
  static const char tstr[] = " [|ahcp]";
  
  #define AHCP_MAGIC_NUMBER 43
  #define AHCP_VERSION_1 1
  #define AHCP1_HEADER_FIX_LEN 24
  #define AHCP1_BODY_MIN_LEN 4
  
  #define AHCP1_MSG_DISCOVER 0
  #define AHCP1_MSG_OFFER    1
  #define AHCP1_MSG_REQUEST  2
  #define AHCP1_MSG_ACK      3
  #define AHCP1_MSG_NACK     4
  #define AHCP1_MSG_RELEASE  5
  
  static const struct tok ahcp1_msg_str[] = {
  	{ AHCP1_MSG_DISCOVER, "Discover" },
  	{ AHCP1_MSG_OFFER,    "Offer"    },
  	{ AHCP1_MSG_REQUEST,  "Request"  },
  	{ AHCP1_MSG_ACK,      "Ack"      },
  	{ AHCP1_MSG_NACK,     "Nack"     },
  	{ AHCP1_MSG_RELEASE,  "Release"  },
  	{ 0, NULL }
  };
  
  #define AHCP1_OPT_PAD                     0
  #define AHCP1_OPT_MANDATORY               1
  #define AHCP1_OPT_ORIGIN_TIME             2
  #define AHCP1_OPT_EXPIRES                 3
  #define AHCP1_OPT_MY_IPV6_ADDRESS         4
  #define AHCP1_OPT_MY_IPV4_ADDRESS         5
  #define AHCP1_OPT_IPV6_PREFIX             6
  #define AHCP1_OPT_IPV4_PREFIX             7
  #define AHCP1_OPT_IPV6_ADDRESS            8
  #define AHCP1_OPT_IPV4_ADDRESS            9
  #define AHCP1_OPT_IPV6_PREFIX_DELEGATION 10
  #define AHCP1_OPT_IPV4_PREFIX_DELEGATION 11
  #define AHCP1_OPT_NAME_SERVER            12
  #define AHCP1_OPT_NTP_SERVER             13
  #define AHCP1_OPT_MAX                    13
  
  static const struct tok ahcp1_opt_str[] = {
  	{ AHCP1_OPT_PAD,                    "Pad"                    },
  	{ AHCP1_OPT_MANDATORY,              "Mandatory"              },
  	{ AHCP1_OPT_ORIGIN_TIME,            "Origin Time"            },
  	{ AHCP1_OPT_EXPIRES,                "Expires"                },
  	{ AHCP1_OPT_MY_IPV6_ADDRESS,        "My-IPv6-Address"        },
  	{ AHCP1_OPT_MY_IPV4_ADDRESS,        "My-IPv4-Address"        },
  	{ AHCP1_OPT_IPV6_PREFIX,            "IPv6 Prefix"            },
  	{ AHCP1_OPT_IPV4_PREFIX,            "IPv4 Prefix"            },
  	{ AHCP1_OPT_IPV6_ADDRESS,           "IPv6 Address"           },
  	{ AHCP1_OPT_IPV4_ADDRESS,           "IPv4 Address"           },
  	{ AHCP1_OPT_IPV6_PREFIX_DELEGATION, "IPv6 Prefix Delegation" },
  	{ AHCP1_OPT_IPV4_PREFIX_DELEGATION, "IPv4 Prefix Delegation" },
  	{ AHCP1_OPT_NAME_SERVER,            "Name Server"            },
  	{ AHCP1_OPT_NTP_SERVER,             "NTP Server"             },
  	{ 0, NULL }
  };
  
  static int
  ahcp_time_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
  {
  	time_t t;
  	struct tm *tm;
  	char buf[BUFSIZE];
  
  	if (cp + 4 != ep)
  		goto invalid;
  	ND_TCHECK_4(cp);
  	t = EXTRACT_BE_U_4(cp);
  	if (NULL == (tm = gmtime(&t)))
  		ND_PRINT(": gmtime() error");
  	else if (0 == strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm))
  		ND_PRINT(": strftime() error");
  	else
  		ND_PRINT(": %s UTC", buf);
  	return 0;
  
  invalid:
  	ND_PRINT("%s", istr);
  	ND_TCHECK_LEN(cp, ep - cp);
  	return 0;
  trunc:
  	ND_PRINT("%s", tstr);
  	return -1;
  }
  
  static int
  ahcp_seconds_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
  {
  	if (cp + 4 != ep)
  		goto invalid;
  	ND_TCHECK_4(cp);
  	ND_PRINT(": %us", EXTRACT_BE_U_4(cp));
  	return 0;
  
  invalid:
  	ND_PRINT("%s", istr);
  	ND_TCHECK_LEN(cp, ep - cp);
  	return 0;
  trunc:
  	ND_PRINT("%s", tstr);
  	return -1;
  }
  
  static int
  ahcp_ipv6_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
  {
  	const char *sep = ": ";
  
  	while (cp < ep) {
  		if (cp + 16 > ep)
  			goto invalid;
  		ND_TCHECK_16(cp);
  		ND_PRINT("%s%s", sep, ip6addr_string(ndo, cp));
  		cp += 16;
  		sep = ", ";
  	}
  	return 0;
  
  invalid:
  	ND_PRINT("%s", istr);
  	ND_TCHECK_LEN(cp, ep - cp);
  	return 0;
  trunc:
  	ND_PRINT("%s", tstr);
  	return -1;
  }
  
  static int
  ahcp_ipv4_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
  {
  	const char *sep = ": ";
  
  	while (cp < ep) {
  		if (cp + 4 > ep)
  			goto invalid;
  		ND_TCHECK_4(cp);
  		ND_PRINT("%s%s", sep, ipaddr_string(ndo, cp));
  		cp += 4;
  		sep = ", ";
  	}
  	return 0;
  
  invalid:
  	ND_PRINT("%s", istr);
  	ND_TCHECK_LEN(cp, ep - cp);
  	return 0;
  trunc:
  	ND_PRINT("%s", tstr);
  	return -1;
  }
  
  static int
  ahcp_ipv6_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
  {
  	const char *sep = ": ";
  
  	while (cp < ep) {
  		if (cp + 17 > ep)
  			goto invalid;
  		ND_TCHECK_LEN(cp, 17);
  		ND_PRINT("%s%s/%u", sep, ip6addr_string(ndo, cp), EXTRACT_U_1(cp + 16));
  		cp += 17;
  		sep = ", ";
  	}
  	return 0;
  
  invalid:
  	ND_PRINT("%s", istr);
  	ND_TCHECK_LEN(cp, ep - cp);
  	return 0;
  trunc:
  	ND_PRINT("%s", tstr);
  	return -1;
  }
  
  static int
  ahcp_ipv4_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
  {
  	const char *sep = ": ";
  
  	while (cp < ep) {
  		if (cp + 5 > ep)
  			goto invalid;
  		ND_TCHECK_5(cp);
  		ND_PRINT("%s%s/%u", sep, ipaddr_string(ndo, cp), EXTRACT_U_1(cp + 4));
  		cp += 5;
  		sep = ", ";
  	}
  	return 0;
  
  invalid:
  	ND_PRINT("%s", istr);
  	ND_TCHECK_LEN(cp, ep - cp);
  	return 0;
  trunc:
  	ND_PRINT("%s", tstr);
  	return -1;
  }
  
  /* Data decoders signal truncated data with -1. */
  static int
  (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, const u_char *) = {
  	/* [AHCP1_OPT_PAD]                    = */  NULL,
  	/* [AHCP1_OPT_MANDATORY]              = */  NULL,
  	/* [AHCP1_OPT_ORIGIN_TIME]            = */  ahcp_time_print,
  	/* [AHCP1_OPT_EXPIRES]                = */  ahcp_seconds_print,
  	/* [AHCP1_OPT_MY_IPV6_ADDRESS]        = */  ahcp_ipv6_addresses_print,
  	/* [AHCP1_OPT_MY_IPV4_ADDRESS]        = */  ahcp_ipv4_addresses_print,
  	/* [AHCP1_OPT_IPV6_PREFIX]            = */  ahcp_ipv6_prefixes_print,
  	/* [AHCP1_OPT_IPV4_PREFIX]            = */  NULL,
  	/* [AHCP1_OPT_IPV6_ADDRESS]           = */  ahcp_ipv6_addresses_print,
  	/* [AHCP1_OPT_IPV4_ADDRESS]           = */  ahcp_ipv4_addresses_print,
  	/* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */  ahcp_ipv6_prefixes_print,
  	/* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */  ahcp_ipv4_prefixes_print,
  	/* [AHCP1_OPT_NAME_SERVER]            = */  ahcp_ipv6_addresses_print,
  	/* [AHCP1_OPT_NTP_SERVER]             = */  ahcp_ipv6_addresses_print,
  };
  
  static void
  ahcp1_options_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
  {
  	uint8_t option_no, option_len;
  
  	while (cp < ep) {
  		/* Option no */
  		ND_TCHECK_1(cp);
  		option_no = EXTRACT_U_1(cp);
  		cp += 1;
  		ND_PRINT("\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no));
  		if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
  			continue;
  		/* Length */
  		if (cp + 1 > ep)
  			goto invalid;
  		ND_TCHECK_1(cp);
  		option_len = EXTRACT_U_1(cp);
  		cp += 1;
  		if (cp + option_len > ep)
  			goto invalid;
  		/* Value */
  		if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
  			if (data_decoders[option_no](ndo, cp, cp + option_len) < 0)
  				break; /* truncated and already marked up */
  		} else {
  			ND_PRINT(" (Length %u)", option_len);
  			ND_TCHECK_LEN(cp, option_len);
  		}
  		cp += option_len;
  	}
  	return;
  
  invalid:
  	ND_PRINT("%s", istr);
  	ND_TCHECK_LEN(cp, ep - cp);
  	return;
  trunc:
  	ND_PRINT("%s", tstr);
  }
  
  static void
  ahcp1_body_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
  {
  	uint8_t type, mbz;
  	uint16_t body_len;
  
  	if (cp + AHCP1_BODY_MIN_LEN > ep)
  		goto invalid;
  	/* Type */
  	ND_TCHECK_1(cp);
  	type = EXTRACT_U_1(cp);
  	cp += 1;
  	/* MBZ */
  	ND_TCHECK_1(cp);
  	mbz = EXTRACT_U_1(cp);
  	cp += 1;
  	/* Length */
  	ND_TCHECK_2(cp);
  	body_len = EXTRACT_BE_U_2(cp);
  	cp += 2;
  
  	if (ndo->ndo_vflag) {
  		ND_PRINT("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
  		if (mbz != 0)
  			ND_PRINT(", MBZ %u", mbz);
  		ND_PRINT(", Length %u", body_len);
  	}
  	if (cp + body_len > ep)
  		goto invalid;
  
  	/* Options */
  	if (ndo->ndo_vflag >= 2)
  		ahcp1_options_print(ndo, cp, cp + body_len); /* not ep (ignore extra data) */
  	else
  		ND_TCHECK_LEN(cp, body_len);
  	return;
  
  invalid:
  	ND_PRINT("%s", istr);
  	ND_TCHECK_LEN(cp, ep - cp);
  	return;
  trunc:
  	ND_PRINT("%s", tstr);
  }
  
  void
  ahcp_print(netdissect_options *ndo, const u_char *cp, const u_int len)
  {
  	const u_char *ep = cp + len;
  	uint8_t version;
  
  	ND_PRINT("AHCP");
  	if (len < 2)
  		goto invalid;
  	/* Magic */
  	ND_TCHECK_1(cp);
  	if (EXTRACT_U_1(cp) != AHCP_MAGIC_NUMBER)
  		goto invalid;
  	cp += 1;
  	/* Version */
  	ND_TCHECK_1(cp);
  	version = EXTRACT_U_1(cp);
  	cp += 1;
  	switch (version) {
  		case AHCP_VERSION_1: {
  			ND_PRINT(" Version 1");
  			if (len < AHCP1_HEADER_FIX_LEN)
  				goto invalid;
  			if (!ndo->ndo_vflag) {
  				ND_TCHECK_LEN(cp, AHCP1_HEADER_FIX_LEN - 2);
  				cp += AHCP1_HEADER_FIX_LEN - 2;
  			} else {
  				/* Hopcount */
  				ND_TCHECK_1(cp);
  				ND_PRINT("\n\tHopcount %u", EXTRACT_U_1(cp));
  				cp += 1;
  				/* Original Hopcount */
  				ND_TCHECK_1(cp);
  				ND_PRINT(", Original Hopcount %u", EXTRACT_U_1(cp));
  				cp += 1;
  				/* Nonce */
  				ND_TCHECK_4(cp);
  				ND_PRINT(", Nonce 0x%08x", EXTRACT_BE_U_4(cp));
  				cp += 4;
  				/* Source Id */
  				ND_TCHECK_8(cp);
  				ND_PRINT(", Source Id %s", linkaddr_string(ndo, cp, 0, 8));
  				cp += 8;
  				/* Destination Id */
  				ND_TCHECK_8(cp);
  				ND_PRINT(", Destination Id %s", linkaddr_string(ndo, cp, 0, 8));
  				cp += 8;
  			}
  			/* Body */
  			ahcp1_body_print(ndo, cp, ep);
  			break;
  		}
  		default:
  			ND_PRINT(" Version %u (unknown)", version);
  			break;
  	}
  	return;
  
  invalid:
  	ND_PRINT("%s", istr);
  	ND_TCHECK_LEN(cp, ep - cp);
  	return;
  trunc:
  	ND_PRINT("%s", tstr);
  }
  