/*
 * Copyright (C) 2002 WIDE 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.
 * 3. Neither the name of the project 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 BY THE PROJECT 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 PROJECT 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: IPv6 mobility printer */
/* RFC 3775 */

#include <config.h>

#include "netdissect-stdinc.h"

#include "netdissect.h"
#include "addrtoname.h"
#include "extract.h"

#include "ip6.h"


/* Mobility header */
struct ip6_mobility {
	nd_uint8_t ip6m_pproto;	/* following payload protocol (for PG) */
	nd_uint8_t ip6m_len;	/* length in units of 8 octets */
	nd_uint8_t ip6m_type;	/* message type */
	nd_uint8_t reserved;	/* reserved */
	nd_uint16_t ip6m_cksum;	/* sum of IPv6 pseudo-header and MH */
	union {
		nd_uint16_t	ip6m_un_data16[1]; /* type-specific field */
		nd_uint8_t	ip6m_un_data8[2];  /* type-specific field */
	} ip6m_dataun;
};

#define ip6m_data16	ip6m_dataun.ip6m_un_data16
#define ip6m_data8	ip6m_dataun.ip6m_un_data8

#define IP6M_MINLEN	8

/* https://www.iana.org/assignments/mobility-parameters/mobility-parameters.xhtml */

/* message type */
#define IP6M_BINDING_REQUEST	0	/* Binding Refresh Request */
#define IP6M_HOME_TEST_INIT	1	/* Home Test Init */
#define IP6M_CAREOF_TEST_INIT	2	/* Care-of Test Init */
#define IP6M_HOME_TEST		3	/* Home Test */
#define IP6M_CAREOF_TEST	4	/* Care-of Test */
#define IP6M_BINDING_UPDATE	5	/* Binding Update */
#define IP6M_BINDING_ACK	6	/* Binding Acknowledgement */
#define IP6M_BINDING_ERROR	7	/* Binding Error */
#define IP6M_MAX		7

static const struct tok ip6m_str[] = {
	{ IP6M_BINDING_REQUEST,  "BRR"  },
	{ IP6M_HOME_TEST_INIT,   "HoTI" },
	{ IP6M_CAREOF_TEST_INIT, "CoTI" },
	{ IP6M_HOME_TEST,        "HoT"  },
	{ IP6M_CAREOF_TEST,      "CoT"  },
	{ IP6M_BINDING_UPDATE,   "BU"   },
	{ IP6M_BINDING_ACK,      "BA"   },
	{ IP6M_BINDING_ERROR,    "BE"   },
	{ 0, NULL }
};

static const unsigned ip6m_hdrlen[IP6M_MAX + 1] = {
	IP6M_MINLEN,      /* IP6M_BINDING_REQUEST  */
	IP6M_MINLEN + 8,  /* IP6M_HOME_TEST_INIT   */
	IP6M_MINLEN + 8,  /* IP6M_CAREOF_TEST_INIT */
	IP6M_MINLEN + 16, /* IP6M_HOME_TEST        */
	IP6M_MINLEN + 16, /* IP6M_CAREOF_TEST      */
	IP6M_MINLEN + 4,  /* IP6M_BINDING_UPDATE   */
	IP6M_MINLEN + 4,  /* IP6M_BINDING_ACK      */
	IP6M_MINLEN + 16, /* IP6M_BINDING_ERROR    */
};

/* Mobility Header Options */
#define IP6MOPT_MINLEN		2
#define IP6MOPT_PAD1          0x0	/* Pad1 */
#define IP6MOPT_PADN          0x1	/* PadN */
#define IP6MOPT_REFRESH	      0x2	/* Binding Refresh Advice */
#define IP6MOPT_REFRESH_MINLEN  4
#define IP6MOPT_ALTCOA        0x3	/* Alternate Care-of Address */
#define IP6MOPT_ALTCOA_MINLEN  18
#define IP6MOPT_NONCEID       0x4	/* Nonce Indices */
#define IP6MOPT_NONCEID_MINLEN  6
#define IP6MOPT_AUTH          0x5	/* Binding Authorization Data */
#define IP6MOPT_AUTH_MINLEN    12

static const struct tok ip6m_binding_update_bits [] = {
	{ 0x08, "A" },
	{ 0x04, "H" },
	{ 0x02, "L" },
	{ 0x01, "K" },
	{ 0, NULL }
};

static int
mobility_opt_print(netdissect_options *ndo,
                   const u_char *bp, const unsigned len)
{
	unsigned i, optlen;

	for (i = 0; i < len; i += optlen) {
		if (GET_U_1(bp + i) == IP6MOPT_PAD1)
			optlen = 1;
		else {
			if (i + 1 < len) {
				optlen = GET_U_1(bp + i + 1) + 2;
			} else
				goto trunc;
		}
		if (i + optlen > len)
			goto trunc;
		ND_TCHECK_1(bp + i + optlen);

		switch (GET_U_1(bp + i)) {
		case IP6MOPT_PAD1:
			ND_PRINT("(pad1)");
			break;
		case IP6MOPT_PADN:
			if (len - i < IP6MOPT_MINLEN) {
				ND_PRINT("(padn: trunc)");
				goto trunc;
			}
			ND_PRINT("(padn)");
			break;
		case IP6MOPT_REFRESH:
			if (len - i < IP6MOPT_REFRESH_MINLEN) {
				ND_PRINT("(refresh: trunc)");
				goto trunc;
			}
			/* units of 4 secs */
			ND_PRINT("(refresh: %u)",
				GET_BE_U_2(bp + i + 2) << 2);
			break;
		case IP6MOPT_ALTCOA:
			if (len - i < IP6MOPT_ALTCOA_MINLEN) {
				ND_PRINT("(altcoa: trunc)");
				goto trunc;
			}
			ND_PRINT("(alt-CoA: %s)", GET_IP6ADDR_STRING(bp + i + 2));
			break;
		case IP6MOPT_NONCEID:
			if (len - i < IP6MOPT_NONCEID_MINLEN) {
				ND_PRINT("(ni: trunc)");
				goto trunc;
			}
			ND_PRINT("(ni: ho=0x%04x co=0x%04x)",
				GET_BE_U_2(bp + i + 2),
				GET_BE_U_2(bp + i + 4));
			break;
		case IP6MOPT_AUTH:
			if (len - i < IP6MOPT_AUTH_MINLEN) {
				ND_PRINT("(auth: trunc)");
				goto trunc;
			}
			ND_PRINT("(auth)");
			break;
		default:
			if (len - i < IP6MOPT_MINLEN) {
				ND_PRINT("(sopt_type %u: trunc)",
					 GET_U_1(bp + i));
				goto trunc;
			}
			ND_PRINT("(type-0x%02x: len=%u)", GET_U_1(bp + i),
				 GET_U_1(bp + i + 1));
			break;
		}
	}
	return 0;

trunc:
	return 1;
}

/*
 * Mobility Header
 */
int
mobility_print(netdissect_options *ndo,
               const u_char *bp, const u_char *bp2 _U_)
{
	const struct ip6_mobility *mh;
	const u_char *ep;
	unsigned mhlen, hlen;
	uint8_t type;

	ndo->ndo_protocol = "mobility";
	mh = (const struct ip6_mobility *)bp;

	/* 'ep' points to the end of available data. */
	ep = ndo->ndo_snapend;

	if (!ND_TTEST_1(mh->ip6m_len)) {
		/*
		 * There's not enough captured data to include the
		 * mobility header length.
		 *
		 * Our caller expects us to return the length, however,
		 * so return a value that will run to the end of the
		 * captured data.
		 *
		 * XXX - "ip6_print()" doesn't do anything with the
		 * returned length, however, as it breaks out of the
		 * header-processing loop.
		 */
		mhlen = (unsigned)(ep - bp);
		goto trunc;
	}
	mhlen = (GET_U_1(mh->ip6m_len) + 1) << 3;

	/* XXX ip6m_cksum */

	type = GET_U_1(mh->ip6m_type);
	if (type <= IP6M_MAX && mhlen < ip6m_hdrlen[type]) {
		ND_PRINT("(header length %u is too small for type %u)", mhlen, type);
		goto trunc;
	}
	ND_PRINT("mobility: %s", tok2str(ip6m_str, "type-#%u", type));
	switch (type) {
	case IP6M_BINDING_REQUEST:
		hlen = IP6M_MINLEN;
		break;
	case IP6M_HOME_TEST_INIT:
	case IP6M_CAREOF_TEST_INIT:
		hlen = IP6M_MINLEN;
		if (ndo->ndo_vflag) {
			ND_PRINT(" %s Init Cookie=%08x:%08x",
			       type == IP6M_HOME_TEST_INIT ? "Home" : "Care-of",
			       GET_BE_U_4(bp + hlen),
			       GET_BE_U_4(bp + hlen + 4));
		}
		hlen += 8;
		break;
	case IP6M_HOME_TEST:
	case IP6M_CAREOF_TEST:
		ND_PRINT(" nonce id=0x%x", GET_BE_U_2(mh->ip6m_data16[0]));
		hlen = IP6M_MINLEN;
		if (ndo->ndo_vflag) {
			ND_PRINT(" %s Init Cookie=%08x:%08x",
			       type == IP6M_HOME_TEST ? "Home" : "Care-of",
			       GET_BE_U_4(bp + hlen),
			       GET_BE_U_4(bp + hlen + 4));
		}
		hlen += 8;
		if (ndo->ndo_vflag) {
			ND_PRINT(" %s Keygen Token=%08x:%08x",
			       type == IP6M_HOME_TEST ? "Home" : "Care-of",
			       GET_BE_U_4(bp + hlen),
			       GET_BE_U_4(bp + hlen + 4));
		}
		hlen += 8;
		break;
	case IP6M_BINDING_UPDATE:
	    {
		int bits;
		ND_PRINT(" seq#=%u", GET_BE_U_2(mh->ip6m_data16[0]));
		hlen = IP6M_MINLEN;
		ND_TCHECK_2(bp + hlen);
		bits = (GET_U_1(bp + hlen) & 0xf0) >> 4;
		if (bits) {
			ND_PRINT(" ");
			ND_PRINT("%s",
				 bittok2str_nosep(ip6m_binding_update_bits,
				 "bits-#0x%x", bits));
		}
		/* Reserved (4bits) */
		hlen += 1;
		/* Reserved (8bits) */
		hlen += 1;
		/* units of 4 secs */
		ND_PRINT(" lifetime=%u", GET_BE_U_2(bp + hlen) << 2);
		hlen += 2;
		break;
	    }
	case IP6M_BINDING_ACK:
		ND_PRINT(" status=%u", GET_U_1(mh->ip6m_data8[0]));
		if (GET_U_1(mh->ip6m_data8[1]) & 0x80)
			ND_PRINT(" K");
		/* Reserved (7bits) */
		hlen = IP6M_MINLEN;
		ND_PRINT(" seq#=%u", GET_BE_U_2(bp + hlen));
		hlen += 2;
		/* units of 4 secs */
		ND_PRINT(" lifetime=%u", GET_BE_U_2(bp + hlen) << 2);
		hlen += 2;
		break;
	case IP6M_BINDING_ERROR:
		ND_PRINT(" status=%u", GET_U_1(mh->ip6m_data8[0]));
		/* Reserved */
		hlen = IP6M_MINLEN;
		ND_PRINT(" homeaddr %s", GET_IP6ADDR_STRING(bp + hlen));
		hlen += 16;
		break;
	default:
		ND_PRINT(" len=%u", GET_U_1(mh->ip6m_len));
		return(mhlen);
		break;
	}
	if (ndo->ndo_vflag)
		if (mobility_opt_print(ndo, bp + hlen, mhlen - hlen))
			goto trunc;

	return(mhlen);

 trunc:
	nd_print_trunc(ndo);
	return(-1);
}