[dragonfly.git] / contrib / tcpdump / print-ip.c

/*
 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 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.
 */

#ifndef lint
static const char rcsid[] _U_ =
    "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.149.2.9 2007/09/14 01:30:02 guy Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "addrtoname.h"
#include "interface.h"
#include "extract.h"			/* must come after interface.h */

#include "ip.h"
#include "ipproto.h"

struct tok ip_option_values[] = {
    { IPOPT_EOL, "EOL" },
    { IPOPT_NOP, "NOP" },
    { IPOPT_TS, "timestamp" },
    { IPOPT_SECURITY, "security" },
    { IPOPT_RR, "RR" },
    { IPOPT_SSRR, "SSRR" },
    { IPOPT_LSRR, "LSRR" },
    { IPOPT_RA, "RA" },
    { IPOPT_RFC1393, "traceroute" },
    { 0, NULL }
};

/*
 * print the recorded route in an IP RR, LSRR or SSRR option.
 */
static void
ip_printroute(register const u_char *cp, u_int length)
{
	register u_int ptr;
	register u_int len;

	if (length < 3) {
		printf(" [bad length %u]", length);
		return;
	}
	if ((length + 1) & 3)
		printf(" [bad length %u]", length);
	ptr = cp[2] - 1;
	if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
		printf(" [bad ptr %u]", cp[2]);

	for (len = 3; len < length; len += 4) {
		printf(" %s", ipaddr_string(&cp[len]));
                if (ptr > len)
                        printf(",");
	}
}

/*
 * If source-routing is present and valid, return the final destination.
 * Otherwise, return IP destination.
 *
 * This is used for UDP and TCP pseudo-header in the checksum
 * calculation.
 */
u_int32_t
ip_finddst(const struct ip *ip)
{
	int length;
	int len;
	const u_char *cp;
	u_int32_t retval;

	cp = (const u_char *)(ip + 1);
	length = (IP_HL(ip) << 2) - sizeof(struct ip);

	for (; length > 0; cp += len, length -= len) {
		int tt;

		TCHECK(*cp);
		tt = *cp;
		if (tt == IPOPT_EOL)
			break;
		else if (tt == IPOPT_NOP)
			len = 1;
		else {
			TCHECK(cp[1]);
			len = cp[1];
			if (len < 2)
				break;
		}
		TCHECK2(*cp, len);
		switch (tt) {

		case IPOPT_SSRR:
		case IPOPT_LSRR:
			if (len < 7)
				break;
			memcpy(&retval, cp + len - 4, 4);
			return retval;
		}
	}
trunc:
	memcpy(&retval, &ip->ip_dst.s_addr, sizeof(u_int32_t));
	return retval;
}

static void
ip_printts(register const u_char *cp, u_int length)
{
	register u_int ptr;
	register u_int len;
	int hoplen;
	const char *type;

	if (length < 4) {
		printf("[bad length %u]", length);
		return;
	}
	printf(" TS{");
	hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
	if ((length - 4) & (hoplen-1))
		printf("[bad length %u]", length);
	ptr = cp[2] - 1;
	len = 0;
	if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
		printf("[bad ptr %u]", cp[2]);
	switch (cp[3]&0xF) {
	case IPOPT_TS_TSONLY:
		printf("TSONLY");
		break;
	case IPOPT_TS_TSANDADDR:
		printf("TS+ADDR");
		break;
	/*
	 * prespecified should really be 3, but some ones might send 2
	 * instead, and the IPOPT_TS_PRESPEC constant can apparently
	 * have both values, so we have to hard-code it here.
	 */

	case 2:
		printf("PRESPEC2.0");
		break;
	case 3:			/* IPOPT_TS_PRESPEC */
		printf("PRESPEC");
		break;
	default:
		printf("[bad ts type %d]", cp[3]&0xF);
		goto done;
	}

	type = " ";
	for (len = 4; len < length; len += hoplen) {
		if (ptr == len)
			type = " ^ ";
		printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
		       hoplen!=8 ? "" : ipaddr_string(&cp[len]));
		type = " ";
	}

done:
	printf("%s", ptr == len ? " ^ " : "");

	if (cp[3]>>4)
		printf(" [%d hops not recorded]} ", cp[3]>>4);
	else
		printf("}");
}

/*
 * print IP options.
 */
static void
ip_optprint(register const u_char *cp, u_int length)
{
	register u_int option_len;
	const char *sep = "";

	for (; length > 0; cp += option_len, length -= option_len) {
		u_int option_code;

		printf("%s", sep);
		sep = ",";

		TCHECK(*cp);
		option_code = *cp;

                printf("%s",
                        tok2str(ip_option_values,"unknown %u",option_code));

		if (option_code == IPOPT_NOP ||
                    option_code == IPOPT_EOL)
			option_len = 1;

		else {
			TCHECK(cp[1]);
			option_len = cp[1];
			if (option_len < 2) {
		                printf(" [bad length %u]", option_len);
				return;
			}
		}

		if (option_len > length) {
	                printf(" [bad length %u]", option_len);
			return;
		}

                TCHECK2(*cp, option_len);

		switch (option_code) {
		case IPOPT_EOL:
			return;

		case IPOPT_TS:
			ip_printts(cp, option_len);
			break;

		case IPOPT_RR:       /* fall through */
		case IPOPT_SSRR:
		case IPOPT_LSRR:
			ip_printroute(cp, option_len);
			break;

		case IPOPT_RA:
			if (option_len < 4) {
				printf(" [bad length %u]", option_len);
				break;
			}
                        TCHECK(cp[3]);
                        if (EXTRACT_16BITS(&cp[2]) != 0)
                            printf(" value %u", EXTRACT_16BITS(&cp[2]));
			break;

		case IPOPT_NOP:       /* nothing to print - fall through */
		case IPOPT_SECURITY:
		default:
			break;
		}
	}
	return;

trunc:
	printf("[|ip]");
}

/*
 * compute an IP header checksum.
 * don't modifiy the packet.
 */
u_short
in_cksum(const u_short *addr, register u_int len, int csum)
{
	int nleft = len;
	const u_short *w = addr;
	u_short answer;
	int sum = csum;

	/*
	 *  Our algorithm is simple, using a 32 bit accumulator (sum),
	 *  we add sequential 16 bit words to it, and at the end, fold
	 *  back all the carry bits from the top 16 bits into the lower
	 *  16 bits.
	 */
	while (nleft > 1)  {
		sum += *w++;
		nleft -= 2;
	}
	if (nleft == 1)
		sum += htons(*(u_char *)w<<8);

	/*
	 * add back carry outs from top 16 bits to low 16 bits
	 */
	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
	sum += (sum >> 16);			/* add carry */
	answer = ~sum;				/* truncate to 16 bits */
	return (answer);
}

/*
 * Given the host-byte-order value of the checksum field in a packet
 * header, and the network-byte-order computed checksum of the data
 * that the checksum covers (including the checksum itself), compute
 * what the checksum field *should* have been.
 */
u_int16_t
in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
{
	u_int32_t shouldbe;

	/*
	 * The value that should have gone into the checksum field
	 * is the negative of the value gotten by summing up everything
	 * *but* the checksum field.
	 *
	 * We can compute that by subtracting the value of the checksum
	 * field from the sum of all the data in the packet, and then
	 * computing the negative of that value.
	 *
	 * "sum" is the value of the checksum field, and "computed_sum"
	 * is the negative of the sum of all the data in the packets,
	 * so that's -(-computed_sum - sum), or (sum + computed_sum).
	 *
	 * All the arithmetic in question is one's complement, so the
	 * addition must include an end-around carry; we do this by
	 * doing the arithmetic in 32 bits (with no sign-extension),
	 * and then adding the upper 16 bits of the sum, which contain
	 * the carry, to the lower 16 bits of the sum, and then do it
	 * again in case *that* sum produced a carry.
	 *
	 * As RFC 1071 notes, the checksum can be computed without
	 * byte-swapping the 16-bit words; summing 16-bit words
	 * on a big-endian machine gives a big-endian checksum, which
	 * can be directly stuffed into the big-endian checksum fields
	 * in protocol headers, and summing words on a little-endian
	 * machine gives a little-endian checksum, which must be
	 * byte-swapped before being stuffed into a big-endian checksum
	 * field.
	 *
	 * "computed_sum" is a network-byte-order value, so we must put
	 * it in host byte order before subtracting it from the
	 * host-byte-order value from the header; the adjusted checksum
	 * will be in host byte order, which is what we'll return.
	 */
	shouldbe = sum;
	shouldbe += ntohs(computed_sum);
	shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
	shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
	return shouldbe;
}

#define IP_RES 0x8000

static struct tok ip_frag_values[] = {
        { IP_MF,        "+" },
        { IP_DF,        "DF" },
	{ IP_RES,       "rsvd" }, /* The RFC3514 evil ;-) bit */
        { 0,            NULL }
};

struct ip_print_demux_state {
	const struct ip *ip;
	const u_char *cp;
	u_int   len, off;
	u_char  nh;
	int     advance;
};

static void
ip_print_demux(netdissect_options *ndo,
	       struct ip_print_demux_state *ipds)
{
	struct protoent *proto;

again:
	switch (ipds->nh) {

	case IPPROTO_AH:
		ipds->nh = *ipds->cp;
		ipds->advance = ah_print(ipds->cp);
		if (ipds->advance <= 0)
			break;
		ipds->cp += ipds->advance;
		ipds->len -= ipds->advance;
		goto again;

	case IPPROTO_ESP:
	{
		int enh, padlen;
		ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
				    (const u_char *)ipds->ip,
				    &enh, &padlen);
		if (ipds->advance <= 0)
			break;
		ipds->cp += ipds->advance;
		ipds->len -= ipds->advance + padlen;
		ipds->nh = enh & 0xff;
		goto again;
	}
	
	case IPPROTO_IPCOMP:
	{
		int enh;
		ipds->advance = ipcomp_print(ipds->cp, &enh);
		if (ipds->advance <= 0)
			break;
		ipds->cp += ipds->advance;
		ipds->len -= ipds->advance;
		ipds->nh = enh & 0xff;
		goto again;
	}

	case IPPROTO_SCTP:
		sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
		break;

	case IPPROTO_DCCP:
		dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
		break;
		
	case IPPROTO_TCP:
		/* pass on the MF bit plus the offset to detect fragments */
		tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
			  ipds->off & (IP_MF|IP_OFFMASK));
		break;
		
	case IPPROTO_UDP:
		/* pass on the MF bit plus the offset to detect fragments */
		udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
			  ipds->off & (IP_MF|IP_OFFMASK));
		break;
		
	case IPPROTO_ICMP:
		/* pass on the MF bit plus the offset to detect fragments */
		icmp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
			   ipds->off & (IP_MF|IP_OFFMASK));
		break;
		
	case IPPROTO_PIGP:
		/*
		 * XXX - the current IANA protocol number assignments
		 * page lists 9 as "any private interior gateway
		 * (used by Cisco for their IGRP)" and 88 as
		 * "EIGRP" from Cisco.
		 *
		 * Recent BSD <netinet/in.h> headers define
		 * IP_PROTO_PIGP as 9 and IP_PROTO_IGRP as 88.
		 * We define IP_PROTO_PIGP as 9 and
		 * IP_PROTO_EIGRP as 88; those names better
		 * match was the current protocol number
		 * assignments say.
		 */
		igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
		break;
		
	case IPPROTO_EIGRP:
		eigrp_print(ipds->cp, ipds->len);
		break;
		
	case IPPROTO_ND:
		ND_PRINT((ndo, " nd %d", ipds->len));
		break;

	case IPPROTO_EGP:
		egp_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_OSPF:
		ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
		break;

	case IPPROTO_IGMP:
		igmp_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_IPV4:
		/* DVMRP multicast tunnel (ip-in-ip encapsulation) */
		ip_print(gndo, ipds->cp, ipds->len);
		if (! vflag) {
			ND_PRINT((ndo, " (ipip-proto-4)"));
			return;
		}
		break;
		
#ifdef INET6
	case IPPROTO_IPV6:
		/* ip6-in-ip encapsulation */
		ip6_print(ipds->cp, ipds->len);
		break;
#endif /*INET6*/

	case IPPROTO_RSVP:
		rsvp_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_GRE:
		/* do it */
		gre_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_MOBILE:
		mobile_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_PIM:
		pim_print(ipds->cp,  ipds->len);
		break;

	case IPPROTO_VRRP:
		vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
		break;

	case IPPROTO_PGM:
		pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
		break;

	default:
		if ((proto = getprotobynumber(ipds->nh)) != NULL)
			ND_PRINT((ndo, " %s", proto->p_name));
		else
			ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
		ND_PRINT((ndo, " %d", ipds->len));
		break;
	}
}
	       
void
ip_print_inner(netdissect_options *ndo,
	       const u_char *bp,
	       u_int length, u_int nh,
	       const u_char *bp2)
{
	struct ip_print_demux_state  ipd;

	ipd.ip = (const struct ip *)bp2;
	ipd.cp = bp;
	ipd.len  = length;
	ipd.off  = 0;
	ipd.nh   = nh;
	ipd.advance = 0;

	ip_print_demux(ndo, &ipd);
}


/*
 * print an IP datagram.
 */
void
ip_print(netdissect_options *ndo,
	 const u_char *bp,
	 u_int length)
{
	struct ip_print_demux_state  ipd;
	struct ip_print_demux_state *ipds=&ipd;
	const u_char *ipend;
	u_int hlen;
	u_int16_t sum, ip_sum;
	struct protoent *proto;

	ipds->ip = (const struct ip *)bp;
	if (IP_V(ipds->ip) != 4) { /* print version if != 4 */
	    printf("IP%u ", IP_V(ipds->ip));
	    if (IP_V(ipds->ip) == 6)
		printf(", wrong link-layer encapsulation");
	}
        else if (!eflag)
	    printf("IP ");

	if ((u_char *)(ipds->ip + 1) > snapend) {
		printf("[|ip]");
		return;
	}
	if (length < sizeof (struct ip)) {
		(void)printf("truncated-ip %u", length);
		return;
	}
	hlen = IP_HL(ipds->ip) * 4;
	if (hlen < sizeof (struct ip)) {
		(void)printf("bad-hlen %u", hlen);
		return;
	}

	ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
	if (length < ipds->len)
		(void)printf("truncated-ip - %u bytes missing! ",
			ipds->len - length);
	if (ipds->len < hlen) {
#ifdef GUESS_TSO
            if (ipds->len) {
                (void)printf("bad-len %u", ipds->len);
                return;
            }
            else {
                /* we guess that it is a TSO send */
                ipds->len = length;
            }
#else
            (void)printf("bad-len %u", ipds->len);
            return;
#endif /* GUESS_TSO */
	}

	/*
	 * Cut off the snapshot length to the end of the IP payload.
	 */
	ipend = bp + ipds->len;
	if (ipend < snapend)
		snapend = ipend;

	ipds->len -= hlen;

	ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);

        if (vflag) {
            (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
            /* ECN bits */
            if (ipds->ip->ip_tos & 0x03) {
                switch (ipds->ip->ip_tos & 0x03) {
                case 1:
                    (void)printf(",ECT(1)");
                    break;
                case 2:
                    (void)printf(",ECT(0)");
                    break;
                case 3:
                    (void)printf(",CE");
                }
            }

            if (ipds->ip->ip_ttl >= 1)
                (void)printf(", ttl %u", ipds->ip->ip_ttl);    

	    /*
	     * for the firewall guys, print id, offset.
             * On all but the last stick a "+" in the flags portion.
	     * For unfragmented datagrams, note the don't fragment flag.
	     */

	    (void)printf(", id %u, offset %u, flags [%s], proto %s (%u)",
                         EXTRACT_16BITS(&ipds->ip->ip_id),
                         (ipds->off & 0x1fff) * 8,
                         bittok2str(ip_frag_values, "none", ipds->off&0xe000),
                         tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
                         ipds->ip->ip_p);

            (void)printf(", length %u", EXTRACT_16BITS(&ipds->ip->ip_len));

            if ((hlen - sizeof(struct ip)) > 0) {
                printf(", options (");
                ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
                printf(")");
            }

	    if ((u_char *)ipds->ip + hlen <= snapend) {
	        sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
		if (sum != 0) {
		    ip_sum = EXTRACT_16BITS(&ipds->ip->ip_sum);
		    (void)printf(", bad cksum %x (->%x)!", ip_sum,
			     in_cksum_shouldbe(ip_sum, sum));
		}
	    }

            printf(") ");
	}

	/*
	 * If this is fragment zero, hand it to the next higher
	 * level protocol.
	 */
	if ((ipds->off & 0x1fff) == 0) {
		ipds->cp = (const u_char *)ipds->ip + hlen;
		ipds->nh = ipds->ip->ip_p;

		if (ipds->nh != IPPROTO_TCP && ipds->nh != IPPROTO_UDP &&
		    ipds->nh != IPPROTO_SCTP && ipds->nh != IPPROTO_DCCP) {
			(void)printf("%s > %s: ",
				     ipaddr_string(&ipds->ip->ip_src),
				     ipaddr_string(&ipds->ip->ip_dst));
		}
		ip_print_demux(ndo, ipds);
	} else {
	    /* Ultra quiet now means that all this stuff should be suppressed */
	    if (qflag > 1) return;

	    /*
	     * if this isn't the first frag, we're missing the
	     * next level protocol header.  print the ip addr
	     * and the protocol.
	     */
	    if (ipds->off & 0x1fff) {
	        (void)printf("%s > %s:", ipaddr_string(&ipds->ip->ip_src),
			     ipaddr_string(&ipds->ip->ip_dst));
		if ((proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
		    (void)printf(" %s", proto->p_name);
		else
		    (void)printf(" ip-proto-%d", ipds->ip->ip_p);
	    } 
	}
}

void
ipN_print(register const u_char *bp, register u_int length)
{
	struct ip *ip, hdr;

	ip = (struct ip *)bp;
	if (length < 4) {
		(void)printf("truncated-ip %d", length);
		return;
	}
	memcpy (&hdr, (char *)ip, 4);
	switch (IP_V(&hdr)) {
	case 4:
		ip_print (gndo, bp, length);
		return;
#ifdef INET6
	case 6:
		ip6_print (bp, length);
		return;
#endif
	default:
		(void)printf("unknown ip %d", IP_V(&hdr));
		return;
	}
}

/*
 * Local Variables:
 * c-style: whitesmith
 * c-basic-offset: 8
 * End:
 */
Commit	Line	Data
c8cf0f94 PA	1	/*
	2	* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that: (1) source code distributions
	7	* retain the above copyright notice and this paragraph in its entirety, (2)
	8	* distributions including binary code include the above copyright notice and
	9	* this paragraph in its entirety in the documentation or other materials
	10	* provided with the distribution, and (3) all advertising materials mentioning
	11	* features or use of this software display the following acknowledgement:
	12	* ``This product includes software developed by the University of California,
	13	* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
	14	* the University nor the names of its contributors may be used to endorse
	15	* or promote products derived from this software without specific prior
	16	* written permission.
	17	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
	18	* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
	19	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
	20	*/
	21
	22	#ifndef lint
	23	static const char rcsid[] _U_ =
825e8fa1	24	"@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.149.2.9 2007/09/14 01:30:02 guy Exp $ (LBL)";
c8cf0f94 PA	25	#endif
	26
	27	#ifdef HAVE_CONFIG_H
	28	#include "config.h"
	29	#endif
	30
	31	#include <tcpdump-stdinc.h>
	32
	33	#include <stdio.h>
	34	#include <stdlib.h>
	35	#include <string.h>
	36
	37	#include "addrtoname.h"
	38	#include "interface.h"
	39	#include "extract.h" /* must come after interface.h */
	40
	41	#include "ip.h"
	42	#include "ipproto.h"
	43
	44	struct tok ip_option_values[] = {
	45	{ IPOPT_EOL, "EOL" },
	46	{ IPOPT_NOP, "NOP" },
	47	{ IPOPT_TS, "timestamp" },
	48	{ IPOPT_SECURITY, "security" },
	49	{ IPOPT_RR, "RR" },
	50	{ IPOPT_SSRR, "SSRR" },
	51	{ IPOPT_LSRR, "LSRR" },
	52	{ IPOPT_RA, "RA" },
825e8fa1	53	{ IPOPT_RFC1393, "traceroute" },
c8cf0f94 PA	54	{ 0, NULL }
	55	};
	56
	57	/*
	58	* print the recorded route in an IP RR, LSRR or SSRR option.
	59	*/
	60	static void
	61	ip_printroute(register const u_char *cp, u_int length)
	62	{
	63	register u_int ptr;
	64	register u_int len;
	65
	66	if (length < 3) {
	67	printf(" [bad length %u]", length);
	68	return;
	69	}
	70	if ((length + 1) & 3)
	71	printf(" [bad length %u]", length);
	72	ptr = cp[2] - 1;
	73	if (ptr < 3 \|\| ((ptr + 1) & 3) \|\| ptr > length + 1)
	74	printf(" [bad ptr %u]", cp[2]);
	75
	76	for (len = 3; len < length; len += 4) {
	77	printf(" %s", ipaddr_string(&cp[len]));
	78	if (ptr > len)
	79	printf(",");
	80	}
	81	}
	82
	83	/*
	84	* If source-routing is present and valid, return the final destination.
	85	* Otherwise, return IP destination.
	86	*
	87	* This is used for UDP and TCP pseudo-header in the checksum
	88	* calculation.
	89	*/
	90	u_int32_t
	91	ip_finddst(const struct ip *ip)
	92	{
	93	int length;
	94	int len;
	95	const u_char *cp;
	96	u_int32_t retval;
	97
	98	cp = (const u_char *)(ip + 1);
	99	length = (IP_HL(ip) << 2) - sizeof(struct ip);
	100
	101	for (; length > 0; cp += len, length -= len) {
	102	int tt;
	103
	104	TCHECK(*cp);
	105	tt = *cp;
	106	if (tt == IPOPT_EOL)
	107	break;
	108	else if (tt == IPOPT_NOP)
	109	len = 1;
	110	else {
	111	TCHECK(cp[1]);
	112	len = cp[1];
	113	if (len < 2)
	114	break;
	115	}
	116	TCHECK2(*cp, len);
	117	switch (tt) {
118
119	case IPOPT_SSRR:
120	case IPOPT_LSRR:
121	if (len < 7)
122	break;
123	memcpy(&retval, cp + len - 4, 4);
124	return retval;
125	}
126	}
127	trunc:
128	memcpy(&retval, &ip->ip_dst.s_addr, sizeof(u_int32_t));
129	return retval;
130	}
131
132	static void
133	ip_printts(register const u_char *cp, u_int length)
134	{
135	register u_int ptr;
136	register u_int len;
137	int hoplen;
138	const char *type;
139
140	if (length < 4) {
141	printf("[bad length %u]", length);
142	return;
143	}
144	printf(" TS{");
145	hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
146	if ((length - 4) & (hoplen-1))
147	printf("[bad length %u]", length);
148	ptr = cp[2] - 1;
149	len = 0;
150	if (ptr < 4 \|\| ((ptr - 4) & (hoplen-1)) \|\| ptr > length + 1)
151	printf("[bad ptr %u]", cp[2]);
152	switch (cp[3]&0xF) {
153	case IPOPT_TS_TSONLY:
154	printf("TSONLY");
155	break;
156	case IPOPT_TS_TSANDADDR:
157	printf("TS+ADDR");
158	break;
159	/*
160	* prespecified should really be 3, but some ones might send 2
161	* instead, and the IPOPT_TS_PRESPEC constant can apparently
162	* have both values, so we have to hard-code it here.
163	*/
164
165	case 2:
166	printf("PRESPEC2.0");
167	break;
168	case 3: /* IPOPT_TS_PRESPEC */
169	printf("PRESPEC");
170	break;
171	default:
172	printf("[bad ts type %d]", cp[3]&0xF);
173	goto done;
174	}
175
176	type = " ";
177	for (len = 4; len < length; len += hoplen) {
178	if (ptr == len)
179	type = " ^ ";
180	printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
181	hoplen!=8 ? "" : ipaddr_string(&cp[len]));
182	type = " ";
183	}
184
185	done:
186	printf("%s", ptr == len ? " ^ " : "");
187
188	if (cp[3]>>4)
189	printf(" [%d hops not recorded]} ", cp[3]>>4);
190	else
191	printf("}");
192	}
193
194	/*
195	* print IP options.
196	*/
197	static void
198	ip_optprint(register const u_char *cp, u_int length)
199	{
200	register u_int option_len;
201	const char *sep = "";
202
203	for (; length > 0; cp += option_len, length -= option_len) {
204	u_int option_code;
205
206	printf("%s", sep);
207	sep = ",";
208
209	TCHECK(*cp);
210	option_code = *cp;
211
212	printf("%s",
213	tok2str(ip_option_values,"unknown %u",option_code));
214
215	if (option_code == IPOPT_NOP \|\|
216	option_code == IPOPT_EOL)
217	option_len = 1;
218
219	else {
220	TCHECK(cp[1]);
221	option_len = cp[1];
222	if (option_len < 2) {
223	printf(" [bad length %u]", option_len);
224	return;
225	}
226	}
227
228	if (option_len > length) {
229	printf(" [bad length %u]", option_len);
230	return;
231	}
232
233	TCHECK2(*cp, option_len);
234
235	switch (option_code) {
236	case IPOPT_EOL:
237	return;
238
239	case IPOPT_TS:
240	ip_printts(cp, option_len);
241	break;
242
243	case IPOPT_RR: /* fall through */
244	case IPOPT_SSRR:
245	case IPOPT_LSRR:
246	ip_printroute(cp, option_len);
247	break;
248
249	case IPOPT_RA:
250	if (option_len < 4) {
251	printf(" [bad length %u]", option_len);
252	break;
253	}
254	TCHECK(cp[3]);
255	if (EXTRACT_16BITS(&cp[2]) != 0)
256	printf(" value %u", EXTRACT_16BITS(&cp[2]));
257	break;
258
259	case IPOPT_NOP: /* nothing to print - fall through */
260	case IPOPT_SECURITY:
261	default:
262	break;
263	}
264	}
265	return;
266
267	trunc:
268	printf("[\|ip]");
269	}
270
271	/*
272	* compute an IP header checksum.
273	* don't modifiy the packet.
274	*/
275	u_short
276	in_cksum(const u_short *addr, register u_int len, int csum)
277	{
278	int nleft = len;
279	const u_short *w = addr;
280	u_short answer;
281	int sum = csum;
282
283	/*
284	* Our algorithm is simple, using a 32 bit accumulator (sum),
285	* we add sequential 16 bit words to it, and at the end, fold
286	* back all the carry bits from the top 16 bits into the lower
287	* 16 bits.
288	*/
289	while (nleft > 1) {
290	sum += *w++;
291	nleft -= 2;
292	}
293	if (nleft == 1)
294	sum += htons((u_char )w<<8);
295
296	/*
297	* add back carry outs from top 16 bits to low 16 bits
298	*/
299	sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
300	sum += (sum >> 16); /* add carry */
301	answer = ~sum; /* truncate to 16 bits */
302	return (answer);
303	}
304
305	/*
306	* Given the host-byte-order value of the checksum field in a packet
307	* header, and the network-byte-order computed checksum of the data
308	* that the checksum covers (including the checksum itself), compute
309	* what the checksum field should have been.
310	*/
311	u_int16_t
312	in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
313	{
314	u_int32_t shouldbe;
315
316	/*
317	* The value that should have gone into the checksum field
318	* is the negative of the value gotten by summing up everything
319	* but the checksum field.
320	*
321	* We can compute that by subtracting the value of the checksum
322	* field from the sum of all the data in the packet, and then
323	* computing the negative of that value.
324	*
325	* "sum" is the value of the checksum field, and "computed_sum"
326	* is the negative of the sum of all the data in the packets,
327	* so that's -(-computed_sum - sum), or (sum + computed_sum).
328	*
329	* All the arithmetic in question is one's complement, so the
330	* addition must include an end-around carry; we do this by
331	* doing the arithmetic in 32 bits (with no sign-extension),
332	* and then adding the upper 16 bits of the sum, which contain
333	* the carry, to the lower 16 bits of the sum, and then do it
334	* again in case that sum produced a carry.
335	*
336	* As RFC 1071 notes, the checksum can be computed without
337	* byte-swapping the 16-bit words; summing 16-bit words
338	* on a big-endian machine gives a big-endian checksum, which
339	* can be directly stuffed into the big-endian checksum fields
340	* in protocol headers, and summing words on a little-endian
341	* machine gives a little-endian checksum, which must be
342	* byte-swapped before being stuffed into a big-endian checksum
343	* field.
344	*
345	* "computed_sum" is a network-byte-order value, so we must put
346	* it in host byte order before subtracting it from the
347	* host-byte-order value from the header; the adjusted checksum
348	* will be in host byte order, which is what we'll return.
349	*/
350	shouldbe = sum;
351	shouldbe += ntohs(computed_sum);
352	shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
353	shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
354	return shouldbe;
355	}
356
357	#define IP_RES 0x8000
358
359	static struct tok ip_frag_values[] = {
360	{ IP_MF, "+" },
361	{ IP_DF, "DF" },
362	{ IP_RES, "rsvd" }, /* The RFC3514 evil ;-) bit */
363	{ 0, NULL }
364	};
365
366	struct ip_print_demux_state {
367	const struct ip *ip;
368	const u_char *cp;
369	u_int len, off;
370	u_char nh;
371	int advance;
372	};
373
374	static void
375	ip_print_demux(netdissect_options *ndo,
376	struct ip_print_demux_state *ipds)
377	{
378	struct protoent *proto;
379
380	again:
381	switch (ipds->nh) {
382
383	case IPPROTO_AH:
384	ipds->nh = *ipds->cp;
385	ipds->advance = ah_print(ipds->cp);
386	if (ipds->advance <= 0)
387	break;
388	ipds->cp += ipds->advance;
389	ipds->len -= ipds->advance;
390	goto again;
391
392	case IPPROTO_ESP:
393	{
394	int enh, padlen;
395	ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
396	(const u_char *)ipds->ip,
397	&enh, &padlen);
398	if (ipds->advance <= 0)
399	break;
400	ipds->cp += ipds->advance;
401	ipds->len -= ipds->advance + padlen;
402	ipds->nh = enh & 0xff;
403	goto again;
404	}
405
406	case IPPROTO_IPCOMP:
407	{
408	int enh;
409	ipds->advance = ipcomp_print(ipds->cp, &enh);
410	if (ipds->advance <= 0)
411	break;
412	ipds->cp += ipds->advance;
413	ipds->len -= ipds->advance;
414	ipds->nh = enh & 0xff;
415	goto again;
416	}
417
418	case IPPROTO_SCTP:
419	sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
420	break;
421
422	case IPPROTO_DCCP:
423	dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
424	break;
425
426	case IPPROTO_TCP:
427	/* pass on the MF bit plus the offset to detect fragments */
428	tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
429	ipds->off & (IP_MF\|IP_OFFMASK));
430	break;
431
432	case IPPROTO_UDP:
433	/* pass on the MF bit plus the offset to detect fragments */
434	udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
435	ipds->off & (IP_MF\|IP_OFFMASK));
436	break;
437
438	case IPPROTO_ICMP:
439	/* pass on the MF bit plus the offset to detect fragments */
440	icmp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
441	ipds->off & (IP_MF\|IP_OFFMASK));
442	break;
443
444	case IPPROTO_PIGP:
445	/*
446	* XXX - the current IANA protocol number assignments
447	* page lists 9 as "any private interior gateway
448	* (used by Cisco for their IGRP)" and 88 as
449	* "EIGRP" from Cisco.
450	*
451	* Recent BSD <netinet/in.h> headers define
452	* IP_PROTO_PIGP as 9 and IP_PROTO_IGRP as 88.
453	* We define IP_PROTO_PIGP as 9 and
454	* IP_PROTO_EIGRP as 88; those names better
455	* match was the current protocol number
456	* assignments say.
457	*/
458	igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
459	break;
460
461	case IPPROTO_EIGRP:
462	eigrp_print(ipds->cp, ipds->len);
463	break;
464
465	case IPPROTO_ND:
466	ND_PRINT((ndo, " nd %d", ipds->len));
467	break;
468
469	case IPPROTO_EGP:
470	egp_print(ipds->cp, ipds->len);
471	break;
472
473	case IPPROTO_OSPF:
474	ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
475	break;
476
477	case IPPROTO_IGMP:
478	igmp_print(ipds->cp, ipds->len);
479	break;
480
481	case IPPROTO_IPV4:
482	/* DVMRP multicast tunnel (ip-in-ip encapsulation) */
483	ip_print(gndo, ipds->cp, ipds->len);
484	if (! vflag) {
485	ND_PRINT((ndo, " (ipip-proto-4)"));
486	return;
487	}
488	break;
489
490	#ifdef INET6
491	case IPPROTO_IPV6:
492	/* ip6-in-ip encapsulation */
493	ip6_print(ipds->cp, ipds->len);
494	break;
495	#endif /INET6/
496
497	case IPPROTO_RSVP:
498	rsvp_print(ipds->cp, ipds->len);
499	break;
500
501	case IPPROTO_GRE:
502	/* do it */
503	gre_print(ipds->cp, ipds->len);
504	break;
505
506	case IPPROTO_MOBILE:
507	mobile_print(ipds->cp, ipds->len);
508	break;
509
510	case IPPROTO_PIM:
511	pim_print(ipds->cp, ipds->len);
512	break;
513
514	case IPPROTO_VRRP:
515	vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
516	break;
517
518	case IPPROTO_PGM:
519	pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
520	break;
521
522	default:
523	if ((proto = getprotobynumber(ipds->nh)) != NULL)
524	ND_PRINT((ndo, " %s", proto->p_name));
525	else
526	ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
527	ND_PRINT((ndo, " %d", ipds->len));
528	break;
529	}
530	}
531
532	void
533	ip_print_inner(netdissect_options *ndo,
534	const u_char *bp,
535	u_int length, u_int nh,
536	const u_char *bp2)
537	{
538	struct ip_print_demux_state ipd;
539
540	ipd.ip = (const struct ip *)bp2;
541	ipd.cp = bp;
542	ipd.len = length;
543	ipd.off = 0;
544	ipd.nh = nh;
545	ipd.advance = 0;
546
547	ip_print_demux(ndo, &ipd);
548	}
549
550
551	/*
552	* print an IP datagram.
553	*/
554	void
555	ip_print(netdissect_options *ndo,
556	const u_char *bp,
557	u_int length)
558	{
559	struct ip_print_demux_state ipd;
560	struct ip_print_demux_state *ipds=&ipd;
561	const u_char *ipend;
562	u_int hlen;
563	u_int16_t sum, ip_sum;
564	struct protoent *proto;
565
566	ipds->ip = (const struct ip *)bp;
567	if (IP_V(ipds->ip) != 4) { /* print version if != 4 */
568	printf("IP%u ", IP_V(ipds->ip));
569	if (IP_V(ipds->ip) == 6)
570	printf(", wrong link-layer encapsulation");
571	}
572	else if (!eflag)
573	printf("IP ");
574
575	if ((u_char *)(ipds->ip + 1) > snapend) {
576	printf("[\|ip]");
577	return;
578	}
579	if (length < sizeof (struct ip)) {
580	(void)printf("truncated-ip %u", length);
581	return;
582	}
583	hlen = IP_HL(ipds->ip) * 4;
584	if (hlen < sizeof (struct ip)) {
585	(void)printf("bad-hlen %u", hlen);
586	return;
587	}
588
589	ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
590	if (length < ipds->len)
591	(void)printf("truncated-ip - %u bytes missing! ",
592	ipds->len - length);
593	if (ipds->len < hlen) {
594	#ifdef GUESS_TSO
595	if (ipds->len) {
596	(void)printf("bad-len %u", ipds->len);
597	return;
598	}
599	else {
600	/* we guess that it is a TSO send */
601	ipds->len = length;
602	}
603	#else
604	(void)printf("bad-len %u", ipds->len);
605	return;
606	#endif /* GUESS_TSO */
607	}
608
609	/*
610	* Cut off the snapshot length to the end of the IP payload.
611	*/
612	ipend = bp + ipds->len;
613	if (ipend < snapend)
614	snapend = ipend;
615
616	ipds->len -= hlen;
617
618	ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);
619
620	if (vflag) {
621	(void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
622	/* ECN bits */
623	if (ipds->ip->ip_tos & 0x03) {
624	switch (ipds->ip->ip_tos & 0x03) {
625	case 1:
626	(void)printf(",ECT(1)");
627	break;
628	case 2:
629	(void)printf(",ECT(0)");
630	break;
631	case 3:
632	(void)printf(",CE");
633	}
634	}
635
636	if (ipds->ip->ip_ttl >= 1)
66170f0a	637	(void)printf(", ttl %u", ipds->ip->ip_ttl);
c8cf0f94 PA	638
	639	/*
	640	* for the firewall guys, print id, offset.
	641	* On all but the last stick a "+" in the flags portion.
	642	* For unfragmented datagrams, note the don't fragment flag.
	643	*/
	644
66170f0a	645	(void)printf(", id %u, offset %u, flags [%s], proto %s (%u)",
c8cf0f94 PA	646	EXTRACT_16BITS(&ipds->ip->ip_id),
c8cf0f94 PA	647	(ipds->off & 0x1fff) * 8,
66170f0a	648	bittok2str(ip_frag_values, "none", ipds->off&0xe000),
c8cf0f94 PA	649	tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
	650	ipds->ip->ip_p);
	651
66170f0a	652	(void)printf(", length %u", EXTRACT_16BITS(&ipds->ip->ip_len));
c8cf0f94 PA	653
	654	if ((hlen - sizeof(struct ip)) > 0) {
	655	printf(", options (");
	656	ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
	657	printf(")");
	658	}
	659
	660	if ((u_char *)ipds->ip + hlen <= snapend) {
	661	sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
	662	if (sum != 0) {
	663	ip_sum = EXTRACT_16BITS(&ipds->ip->ip_sum);
	664	(void)printf(", bad cksum %x (->%x)!", ip_sum,
	665	in_cksum_shouldbe(ip_sum, sum));
	666	}
	667	}
	668
	669	printf(") ");
	670	}
	671
	672	/*
	673	* If this is fragment zero, hand it to the next higher
	674	* level protocol.
	675	*/
	676	if ((ipds->off & 0x1fff) == 0) {
	677	ipds->cp = (const u_char *)ipds->ip + hlen;
	678	ipds->nh = ipds->ip->ip_p;
	679
	680	if (ipds->nh != IPPROTO_TCP && ipds->nh != IPPROTO_UDP &&
	681	ipds->nh != IPPROTO_SCTP && ipds->nh != IPPROTO_DCCP) {
	682	(void)printf("%s > %s: ",
	683	ipaddr_string(&ipds->ip->ip_src),
	684	ipaddr_string(&ipds->ip->ip_dst));
	685	}
	686	ip_print_demux(ndo, ipds);
	687	} else {
	688	/* Ultra quiet now means that all this stuff should be suppressed */
	689	if (qflag > 1) return;
	690
	691	/*
	692	* if this isn't the first frag, we're missing the
	693	* next level protocol header. print the ip addr
	694	* and the protocol.
	695	*/
	696	if (ipds->off & 0x1fff) {
	697	(void)printf("%s > %s:", ipaddr_string(&ipds->ip->ip_src),
	698	ipaddr_string(&ipds->ip->ip_dst));
	699	if ((proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
	700	(void)printf(" %s", proto->p_name);
	701	else
	702	(void)printf(" ip-proto-%d", ipds->ip->ip_p);
	703	}
	704	}
	705	}
	706
	707	void
	708	ipN_print(register const u_char *bp, register u_int length)
	709	{
	710	struct ip *ip, hdr;
	711
	712	ip = (struct ip *)bp;
	713	if (length < 4) {
	714	(void)printf("truncated-ip %d", length);
	715	return;
	716	}
717	memcpy (&hdr, (char *)ip, 4);
718	switch (IP_V(&hdr)) {
719	case 4:
720	ip_print (gndo, bp, length);
721	return;
722	#ifdef INET6
723	case 6:
724	ip6_print (bp, length);
725	return;
726	#endif
727	default:
728	(void)printf("unknown ip %d", IP_V(&hdr));
729	return;
730	}
731	}
732
733	/*
734	* Local Variables:
735	* c-style: whitesmith
736	* c-basic-offset: 8
737	* End:
738	*/
739
740