+/*
+ * This module implements decoding of AHCP (Ad Hoc Configuration Protocol) based
+ * on draft-chroboczek-ahcp-00 and source code of ahcpd-0.53.
+ *
+ *
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <tcpdump-stdinc.h>
+
+#include "interface.h"
+#include "extract.h"
+#include "addrtoname.h"
+
+static const char *corrupt_str = "(corrupt)";
+static const char *trunc_str = "[|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(const u_char *cp, const u_char *ep) {
+ time_t t;
+ struct tm *tm;
+ char buf[BUFSIZE];
+
+ if (cp + 4 != ep)
+ goto corrupt;
+ TCHECK2(*cp, 4);
+ t = EXTRACT_32BITS(cp);
+ if (NULL == (tm = gmtime(&t)))
+ printf(": gmtime() error");
+ else if (0 == strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm))
+ printf(": strftime() error");
+ else
+ printf(": %s UTC", buf);
+ return 0;
+
+corrupt:
+ printf(": %s", corrupt_str);
+ TCHECK2(*cp, ep - cp);
+ return 0;
+trunc:
+ printf(" %s", trunc_str);
+ return -1;
+}
+
+static int
+ahcp_seconds_print(const u_char *cp, const u_char *ep) {
+ if (cp + 4 != ep)
+ goto corrupt;
+ TCHECK2(*cp, 4);
+ printf(": %us", EXTRACT_32BITS(cp));
+ return 0;
+
+corrupt:
+ printf(": %s", corrupt_str);
+ TCHECK2(*cp, ep - cp);
+ return 0;
+trunc:
+ printf(" %s", trunc_str);
+ return -1;
+}
+
+static int
+ahcp_ipv6_addresses_print(const u_char *cp, const u_char *ep) {
+ const char *sep = ": ";
+
+ while (cp < ep) {
+ if (cp + 16 > ep)
+ goto corrupt;
+ TCHECK2(*cp, 16);
+ printf("%s%s", sep, ip6addr_string(cp));
+ cp += 16;
+ sep = ", ";
+ }
+ return 0;
+
+corrupt:
+ printf(": %s", corrupt_str);
+ TCHECK2(*cp, ep - cp);
+ return 0;
+trunc:
+ printf(" %s", trunc_str);
+ return -1;
+}
+
+static int
+ahcp_ipv4_addresses_print(const u_char *cp, const u_char *ep) {
+ const char *sep = ": ";
+
+ while (cp < ep) {
+ if (cp + 4 > ep)
+ goto corrupt;
+ TCHECK2(*cp, 4);
+ printf("%s%s", sep, ipaddr_string(cp));
+ cp += 4;
+ sep = ", ";
+ }
+ return 0;
+
+corrupt:
+ printf(": %s", corrupt_str);
+ TCHECK2(*cp, ep - cp);
+ return 0;
+trunc:
+ printf(" %s", trunc_str);
+ return -1;
+}
+
+static int
+ahcp_ipv6_prefixes_print(const u_char *cp, const u_char *ep) {
+ const char *sep = ": ";
+
+ while (cp < ep) {
+ if (cp + 17 > ep)
+ goto corrupt;
+ TCHECK2(*cp, 17);
+ printf("%s%s/%u", sep, ip6addr_string(cp), *(cp + 16));
+ cp += 17;
+ sep = ", ";
+ }
+ return 0;
+
+corrupt:
+ printf(": %s", corrupt_str);
+ TCHECK2(*cp, ep - cp);
+ return 0;
+trunc:
+ printf(" %s", trunc_str);
+ return -1;
+}
+
+static int
+ahcp_ipv4_prefixes_print(const u_char *cp, const u_char *ep) {
+ const char *sep = ": ";
+
+ while (cp < ep) {
+ if (cp + 5 > ep)
+ goto corrupt;
+ TCHECK2(*cp, 5);
+ printf("%s%s/%u", sep, ipaddr_string(cp), *(cp + 4));
+ cp += 5;
+ sep = ", ";
+ }
+ return 0;
+
+corrupt:
+ printf(": %s", corrupt_str);
+ TCHECK2(*cp, ep - cp);
+ return 0;
+trunc:
+ printf(" %s", trunc_str);
+ return -1;
+}
+
+/* Data decoders signal truncated data with -1. */
+static int
+(* const data_decoders[AHCP1_OPT_MAX + 1])(const u_char *, const u_char *) = {
+ [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_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(const u_char *cp, const u_char *ep) {
+ uint8_t option_no, option_len;
+
+ while (cp < ep) {
+ /* Option no */
+ TCHECK2(*cp, 1);
+ option_no = *cp;
+ cp += 1;
+ printf("\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 corrupt;
+ TCHECK2(*cp, 1);
+ option_len = *cp;
+ cp += 1;
+ if (cp + option_len > ep)
+ goto corrupt;
+ /* Value */
+ if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
+ if (data_decoders[option_no](cp, cp + option_len) < 0)
+ break; /* truncated and already marked up */
+ } else {
+ printf(" (Length %u)", option_len);
+ TCHECK2(*cp, option_len);
+ }
+ cp += option_len;
+ }
+ return;
+
+corrupt:
+ printf(" %s", corrupt_str);
+ TCHECK2(*cp, ep - cp);
+ return;
+trunc:
+ printf(" %s", trunc_str);
+}
+
+static void
+ahcp1_body_print(const u_char *cp, const u_char *ep) {
+ uint8_t type, mbz;
+ uint16_t body_len;
+
+ if (cp + AHCP1_BODY_MIN_LEN > ep)
+ goto corrupt;
+ /* Type */
+ TCHECK2(*cp, 1);
+ type = *cp;
+ cp += 1;
+ /* MBZ */
+ TCHECK2(*cp, 1);
+ mbz = *cp;
+ cp += 1;
+ /* Length */
+ TCHECK2(*cp, 2);
+ body_len = EXTRACT_16BITS(cp);
+ cp += 2;
+
+ if (vflag) {
+ printf("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
+ if (mbz != 0)
+ printf(", MBZ %u", mbz);
+ printf(", Length %u", body_len);
+ }
+ if (cp + body_len > ep)
+ goto corrupt;
+
+ /* Options */
+ if (vflag >= 2)
+ ahcp1_options_print(cp, cp + body_len); /* not ep (ignore extra data) */
+ else
+ TCHECK2(*cp, body_len);
+ return;
+
+corrupt:
+ printf(" %s", corrupt_str);
+ TCHECK2(*cp, ep - cp);
+ return;
+trunc:
+ printf(" %s", trunc_str);
+}
+
+void
+ahcp_print(const u_char *cp, const u_int len) {
+ const u_char *ep = cp + len;
+ uint8_t version;
+
+ printf("AHCP");
+ if (len < 2)
+ goto corrupt;
+ /* Magic */
+ TCHECK2(*cp, 1);
+ if (*cp != AHCP_MAGIC_NUMBER)
+ goto corrupt;
+ cp += 1;
+ /* Version */
+ TCHECK2(*cp, 1);
+ version = *cp;
+ cp += 1;
+ switch (version) {
+ case AHCP_VERSION_1: {
+ printf(" Version 1");
+ if (len < AHCP1_HEADER_FIX_LEN)
+ goto corrupt;
+ if (!vflag) {
+ TCHECK2(*cp, AHCP1_HEADER_FIX_LEN - 2);
+ cp += AHCP1_HEADER_FIX_LEN - 2;
+ } else {
+ /* Hopcount */
+ TCHECK2(*cp, 1);
+ printf("\n\tHopcount %u", *cp);
+ cp += 1;
+ /* Original Hopcount */
+ TCHECK2(*cp, 1);
+ printf(", Original Hopcount %u", *cp);
+ cp += 1;
+ /* Nonce */
+ TCHECK2(*cp, 4);
+ printf(", Nonce 0x%08x", EXTRACT_32BITS(cp));
+ cp += 4;
+ /* Source Id */
+ TCHECK2(*cp, 8);
+ printf(", Source Id %s", linkaddr_string(cp, 0, 8));
+ cp += 8;
+ /* Destination Id */
+ TCHECK2(*cp, 8);
+ printf(", Destination Id %s", linkaddr_string(cp, 0, 8));
+ cp += 8;
+ }
+ /* Body */
+ ahcp1_body_print(cp, ep);
+ break;
+ }
+ default:
+ printf(" Version %u (unknown)", version);
+ break;
+ }
+ return;
+
+corrupt:
+ printf(" %s", corrupt_str);
+ TCHECK2(*cp, ep - cp);
+ return;
+trunc:
+ printf(" %s", trunc_str);
+}
+
projects / tcpdump / commitdiff
