[mirror_frr.git] / pimd / mtracebis.c

/*
 * Multicast Traceroute for FRRouting
 * Copyright (C) 2018  Mladen Sablic
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifdef __linux__

#include "pim_igmp_mtrace.h"

#include "checksum.h"
#include "prefix.h"
#include "mtracebis_routeget.h"

#include <sys/select.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <net/if.h>
#include <unistd.h>
#include <getopt.h>
#include <netdb.h>

#define MTRACEBIS_VERSION "0.1"
#define MTRACE_TIMEOUT (5)

#define IP_HDR_LEN (sizeof(struct ip))
#define IP_RA_LEN (4)
#define MTRACE_BUF_LEN (MTRACE_HDR_SIZE + (MTRACE_MAX_HOPS * MTRACE_RSP_SIZE))
#define IP_AND_MTRACE_BUF_LEN (IP_HDR_LEN + IP_RA_LEN + MTRACE_BUF_LEN)

static const char *progname;
static void usage(void)
{
	fprintf(stderr, "Usage : %s <multicast source> [<multicast group>]\n",
		progname);
}
static void version(void)
{
	fprintf(stderr, "%s %s\n", progname, MTRACEBIS_VERSION);
}

static void print_host(struct in_addr addr)
{
	struct hostent *h;

	h = gethostbyaddr(&addr, sizeof(addr), AF_INET);
	if (h == NULL)
		printf("?");
	else
		printf("%s", h->h_name);
	printf(" (%s) ", inet_ntoa(addr));
}

static void print_line_no(int i)
{
	printf("%3d  ", -i);
}

static const char *rtg_proto_str(enum mtrace_rtg_proto proto)
{
	static char buf[80];

	buf[0] = '\0';

	switch (proto) {
	case MTRACE_RTG_PROTO_DVMRP:
		return "DVMRP";
	case MTRACE_RTG_PROTO_MOSPF:
		return "MOSPF";
	case MTRACE_RTG_PROTO_PIM:
		return "PIM";
	case MTRACE_RTG_PROTO_CBT:
		return "CBT";
	case MTRACE_RTG_PROTO_PIM_SPECIAL:
		return "PIM special";
	case MTRACE_RTG_PROTO_PIM_STATIC:
		return "PIM static";
	case MTRACE_RTG_PROTO_DVMRP_STATIC:
		return "DVMRP static";
	case MTRACE_RTG_PROTO_PIM_MBGP:
		return "PIM MBGP";
	case MTRACE_RTG_PROTO_CBT_SPECIAL:
		return "CBT special";
	case MTRACE_RTG_PROTO_CBT_STATIC:
		return "CBT static";
	case MTRACE_RTG_PROTO_PIM_ASSERT:
		return "PIM assert";
	default:
		sprintf(buf, "unknown protocol (%d)", proto);
		return buf;
	}
}

static void print_rtg_proto(uint32_t rtg_proto)
{
	printf("%s", rtg_proto_str(rtg_proto));
}

static void print_fwd_ttl(uint32_t fwd_ttl)
{
	printf("thresh^ %d", fwd_ttl);
}

static const char *fwd_code_str(enum mtrace_fwd_code code)
{
	static char buf[80];

	buf[0] = '\0';

	switch (code) {
	case MTRACE_FWD_CODE_NO_ERROR:
		return "no error";
	case MTRACE_FWD_CODE_WRONG_IF:
		return "wrong interface";
	case MTRACE_FWD_CODE_PRUNE_SENT:
		return "prune sent";
	case MTRACE_FWD_CODE_PRUNE_RCVD:
		return "prune received";
	case MTRACE_FWD_CODE_SCOPED:
		return "scoped";
	case MTRACE_FWD_CODE_NO_ROUTE:
		return "no route";
	case MTRACE_FWD_CODE_WRONG_LAST_HOP:
		return "wrong last hop";
	case MTRACE_FWD_CODE_NOT_FORWARDING:
		return "not forwarding";
	case MTRACE_FWD_CODE_REACHED_RP:
		return "reached RP";
	case MTRACE_FWD_CODE_RPF_IF:
		return "RPF interface";
	case MTRACE_FWD_CODE_NO_MULTICAST:
		return "no multicast";
	case MTRACE_FWD_CODE_INFO_HIDDEN:
		return "info hidden";
	case MTRACE_FWD_CODE_NO_SPACE:
		return "no space";
	case MTRACE_FWD_CODE_OLD_ROUTER:
		return "old router";
	case MTRACE_FWD_CODE_ADMIN_PROHIB:
		return "admin. prohib.";
	default:
		sprintf(buf, "unknown fwd. code (%d)", code);
		return buf;
	}
}

static void print_fwd_code(uint32_t fwd_code)
{
	printf("%s", fwd_code_str(fwd_code));
}

static void print_rsp(struct igmp_mtrace_rsp *rsp)
{
	print_host(rsp->outgoing);
	if (rsp->fwd_code == 0 || rsp->fwd_code == MTRACE_FWD_CODE_REACHED_RP) {
		print_rtg_proto(rsp->rtg_proto);
		printf(" ");
		if (rsp->fwd_code == MTRACE_FWD_CODE_REACHED_RP)
			printf("(RP) ");
		if (rsp->rtg_proto == MTRACE_RTG_PROTO_PIM) {
			switch (rsp->src_mask) {
			case MTRACE_SRC_MASK_GROUP:
				printf("(*,G) ");
				break;
			case MTRACE_SRC_MASK_SOURCE:
				printf("(S,G) ");
				break;
			}
		}
		print_fwd_ttl(rsp->fwd_ttl);
	} else {
		print_fwd_code(rsp->fwd_code);
	}
	printf("\n");
}

static void print_dest(struct igmp_mtrace *mtrace)
{
	print_line_no(0);
	print_host(mtrace->dst_addr);
	printf("\n");
}

static void print_summary(struct igmp_mtrace *mtrace, int hops, long msec)
{
	int i;
	int t = 0;

	for (i = 0; i < hops; i++)
		t += mtrace->rsp[i].fwd_ttl;

	printf("Round trip time %ld ms; total ttl of %d required.\n", msec, t);
}

static void print_responses(struct igmp_mtrace *mtrace, int hops, long msec)
{
	int i;

	print_dest(mtrace);

	for (i = 0; i < hops; i++) {
		print_line_no(i + 1);
		print_rsp(&mtrace->rsp[i]);
	}
	print_summary(mtrace, hops, msec);
}

static int send_query(int fd, struct in_addr to_addr,
		      struct igmp_mtrace *mtrace)
{
	struct sockaddr_in to;
	socklen_t tolen;
	int sent;

	memset(&to, 0, sizeof(to));
	to.sin_family = AF_INET;
	to.sin_addr = to_addr;
	tolen = sizeof(to);

	sent = sendto(fd, (char *)mtrace, sizeof(*mtrace), MSG_DONTWAIT,
		      (struct sockaddr *)&to, tolen);

	if (sent < 1)
		return -1;
	return 0;
}

static void print_query(struct igmp_mtrace *mtrace)
{
	char src_str[INET_ADDRSTRLEN];
	char dst_str[INET_ADDRSTRLEN];
	char grp_str[INET_ADDRSTRLEN];

	printf("* Mtrace from %s to %s via group %s\n",
	       inet_ntop(AF_INET, &mtrace->src_addr, src_str, sizeof(src_str)),
	       inet_ntop(AF_INET, &mtrace->dst_addr, dst_str, sizeof(dst_str)),
	       inet_ntop(AF_INET, &mtrace->grp_addr, grp_str, sizeof(grp_str)));
}

static int recv_response(int fd, int *hops, struct igmp_mtrace *mtracer)
{
	int recvd;
	char mtrace_buf[IP_AND_MTRACE_BUF_LEN];
	struct ip *ip;
	struct igmp_mtrace *mtrace;
	int mtrace_len;
	int responses;
	unsigned short sum;

	recvd = recvfrom(fd, mtrace_buf, IP_AND_MTRACE_BUF_LEN, 0, NULL, 0);

	if (recvd < 1) {
		fprintf(stderr, "recvfrom error: %s\n", strerror(errno));
		return -1;
	}

	if (recvd < (int)sizeof(struct ip)) {
		fprintf(stderr, "no ip header\n");
		return -1;
	}

	ip = (struct ip *)mtrace_buf;

	if (ip->ip_v != 4) {
		fprintf(stderr, "IP not version 4\n");
		return -1;
	}

	sum = ip->ip_sum;
	ip->ip_sum = 0;

	if (sum != in_cksum(ip, ip->ip_hl * 4))
		return -1;

	mtrace = (struct igmp_mtrace *)(mtrace_buf + (4 * ip->ip_hl));

	mtrace_len = ntohs(ip->ip_len) - ip->ip_hl * 4;

	if (mtrace_len < (int)MTRACE_HDR_SIZE)
		return -1;

	sum = mtrace->checksum;
	mtrace->checksum = 0;
	if (sum != in_cksum(mtrace, mtrace_len)) {
		fprintf(stderr, "mtrace checksum wrong\n");
		return -1;
	}

	if (mtrace->type != PIM_IGMP_MTRACE_RESPONSE)
		return -1;


	responses = mtrace_len - sizeof(struct igmp_mtrace);
	responses /= sizeof(struct igmp_mtrace_rsp);

	if (responses > MTRACE_MAX_HOPS) {
		fprintf(stderr, "mtrace too large\n");
		return -1;
	}

	if (hops)
		*hops = responses;

	if (mtracer)
		memcpy(mtracer, mtrace, mtrace_len);

	return 0;
}

static int wait_for_response(int fd, int *hops, struct igmp_mtrace *mtrace,
			     long *ret_msec)
{
	fd_set readfds;
	struct timeval timeout;
	int ret = -1;
	long msec, rmsec, tmsec;

	FD_ZERO(&readfds);
	FD_SET(fd, &readfds);

	memset(&timeout, 0, sizeof(timeout));

	timeout.tv_sec = MTRACE_TIMEOUT;

	tmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	do {
		ret = select(fd + 1, &readfds, NULL, NULL, &timeout);
		if (ret <= 0)
			return ret;
		rmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
		msec = tmsec - rmsec;
	} while (recv_response(fd, hops, mtrace) != 0);

	if (ret_msec)
		*ret_msec = msec;

	return ret;
}

static bool check_end(struct igmp_mtrace *mtrace, int hops)
{
	return mtrace->src_addr.s_addr == mtrace->rsp[hops - 1].prev_hop.s_addr;
}

int main(int argc, char *const argv[])
{
	struct in_addr mc_source;
	struct in_addr mc_group;
	struct in_addr iface_addr;
	struct in_addr gw_addr;
	struct in_addr mtrace_addr;
	struct igmp_mtrace mtrace;
	struct igmp_mtrace *mtracep;
	int hops = 255;
	int rhops;
	int maxhops = 255;
	int perhop = 3;
	int ifindex;
	int unicast = 1;
	int ttl = 64;
	int fd = -1;
	int ret = -1;
	int c;
	long msec;
	int i, j;
	char ifname[IF_NAMESIZE];
	char mbuf[MTRACE_BUF_LEN];
	bool not_group;

	mtrace_addr.s_addr = inet_addr("224.0.1.32");

	uid_t uid = getuid();

	if (uid != 0) {
		printf("must run as root\n");
		exit(EXIT_FAILURE);
	}

	if (argc <= 0)
		progname = "mtracebis";
	else
		progname = argv[0];

	if (argc != 2 && argc != 3) {
		usage();
		exit(EXIT_FAILURE);
	}

	while (1) {
		static struct option long_options[] = {
			{"help", no_argument, 0, 'h'},
			{"version", no_argument, 0, 'v'},
			{0, 0, 0, 0}};
		int option_index = 0;

		c = getopt_long(argc, argv, "vh", long_options, &option_index);

		if (c == -1)
			break;

		switch (c) {
		case 'h':
			usage();
			exit(0);
		case 'v':
			version();
			exit(0);
		default:
			usage();
			exit(EXIT_FAILURE);
		}
	}
	if (inet_pton(AF_INET, argv[1], &mc_source) != 1) {
		usage();
		fprintf(stderr, "%s: %s is not a valid IPv4 address\n", argv[0],
			argv[1]);
		exit(EXIT_FAILURE);
	}

	mc_group.s_addr = 0;
	not_group = false;

	if (argc == 3) {
		if (inet_pton(AF_INET, argv[2], &mc_group) != 1)
			not_group = true;
		if (!not_group && !IPV4_CLASS_DE(ntohl(mc_group.s_addr)))
			not_group = true;
	}

	if (not_group) {
		usage();
		fprintf(stderr, "%s: %s is not a valid IPv4 group address\n",
			argv[0], argv[2]);
		exit(EXIT_FAILURE);
	}

	ifindex = routeget(mc_source, &iface_addr, &gw_addr);
	if (ifindex < 0) {
		fprintf(stderr, "%s: failed to get route to source %s\n",
			argv[0], argv[1]);
		exit(EXIT_FAILURE);
	}

	if (if_indextoname(ifindex, ifname) == NULL) {
		fprintf(stderr, "%s: if_indextoname error: %s\n", argv[0],
			strerror(errno));
		exit(EXIT_FAILURE);
	}

	/* zero mtrace struct */
	memset((char *)&mtrace, 0, sizeof(mtrace));

	/* set up query */
	mtrace.type = PIM_IGMP_MTRACE_QUERY_REQUEST;
	mtrace.hops = hops;
	mtrace.checksum = 0;
	mtrace.grp_addr = mc_group;
	mtrace.src_addr = mc_source;
	mtrace.dst_addr = iface_addr;
	mtrace.rsp_addr = unicast ? iface_addr : mtrace_addr;
	mtrace.rsp_ttl = ttl;
	mtrace.qry_id = 0xffffff & time(NULL);

	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));

	fd = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP);

	if (fd < 1) {
		fprintf(stderr, "%s: socket error: %s\n", argv[0],
			strerror(errno));
		exit(EXIT_FAILURE);
	}

	ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
			 strlen(ifname));

	if (ret < 0) {
		fprintf(stderr, "%s: setsockopt error: %s\n", argv[0],
			strerror(errno));
		ret = EXIT_FAILURE;
		goto close_fd;
	}

	print_query(&mtrace);
	if (send_query(fd, gw_addr, &mtrace) < 0) {
		fprintf(stderr, "%s: sendto error: %s\n", argv[0],
			strerror(errno));
		ret = EXIT_FAILURE;
		goto close_fd;
	}
	printf("Querying full reverse path...\n");
	mtracep = (struct igmp_mtrace *)mbuf;
	ret = wait_for_response(fd, &rhops, mtracep, &msec);
	if (ret > 0) {
		print_responses(mtracep, rhops, msec);
		ret = 0;
		goto close_fd;
	}
	if (ret < 0) {
		fprintf(stderr, "%s: select error: %s\n", argv[0],
			strerror(errno));
		ret = EXIT_FAILURE;
		goto close_fd;
	}
	printf(" * ");
	printf("switching to hop-by-hop:\n");
	print_dest(&mtrace);
	for (i = 1; i < maxhops; i++) {
		print_line_no(i);
		mtrace.hops = i;
		for (j = 0; j < perhop; j++) {
			mtrace.qry_id++;
			mtrace.checksum = 0;
			mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
			if (send_query(fd, gw_addr, &mtrace) < 0) {
				fprintf(stderr, "%s: sendto error: %s\n",
					argv[0], strerror(errno));
				ret = EXIT_FAILURE;
				goto close_fd;
			}
			ret = wait_for_response(fd, &rhops, mtracep, &msec);
			if (ret > 0) {
				if (check_end(mtracep, rhops)) {
					print_rsp(&mtracep->rsp[rhops - 1]);
					print_summary(mtracep, rhops, msec);
					ret = 0;
					goto close_fd;
				}
				if (i > rhops) {
					printf(" * ...giving up.\n");
					ret = 0;
					goto close_fd;
				}
				print_rsp(&mtracep->rsp[rhops - 1]);
				break;
			}
			printf(" *");
		}
		if (ret <= 0)
			printf("\n");
	}
	ret = 0;
close_fd:
	close(fd);
	exit(ret);
}

#else /* __linux__ */

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

int main(int argc, char *argv[])
{
	printf("%s implemented only for GNU/Linux\n", argv[0]);
	exit(0);
}

#endif /* __linux__ */
Commit	Line	Data
4d9ad5dc MS	1	/*
	2	* Multicast Traceroute for FRRouting
	3	* Copyright (C) 2018 Mladen Sablic
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation; either version 2 of the License, or
	8	* (at your option) any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful, but
	11	* WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along
	16	* with this program; see the file COPYING; if not, write to the Free Software
	17	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	18	*/
	19
	20	#ifdef __linux__
	21
	22	#include "pim_igmp_mtrace.h"
	23
	24	#include "checksum.h"
71e55fb2	25	#include "prefix.h"
4d9ad5dc MS	26	#include "mtracebis_routeget.h"
	27
	28	#include <sys/select.h>
	29	#include <netinet/in.h>
	30	#include <arpa/inet.h>
	31	#include <unistd.h>
	32	#include <sys/types.h>
	33	#include <sys/time.h>
	34	#include <stdio.h>
	35	#include <stdlib.h>
	36	#include <string.h>
	37	#include <time.h>
	38	#include <net/if.h>
5b02bd3a DS	39	#include <unistd.h>
5b02bd3a DS	40	#include <getopt.h>
04a2eef3	41	#include <netdb.h>
4d9ad5dc MS	42
	43	#define MTRACEBIS_VERSION "0.1"
	44	#define MTRACE_TIMEOUT (5)
	45
	46	#define IP_HDR_LEN (sizeof(struct ip))
	47	#define IP_RA_LEN (4)
	48	#define MTRACE_BUF_LEN (MTRACE_HDR_SIZE + (MTRACE_MAX_HOPS * MTRACE_RSP_SIZE))
	49	#define IP_AND_MTRACE_BUF_LEN (IP_HDR_LEN + IP_RA_LEN + MTRACE_BUF_LEN)
	50
	51	static const char *progname;
	52	static void usage(void)
	53	{
71e55fb2 MS	54	fprintf(stderr, "Usage : %s <multicast source> [<multicast group>]\n",
71e55fb2 MS	55	progname);
4d9ad5dc MS	56	}
	57	static void version(void)
	58	{
	59	fprintf(stderr, "%s %s\n", progname, MTRACEBIS_VERSION);
	60	}
	61
04a2eef3 MS	62	static void print_host(struct in_addr addr)
	63	{
	64	struct hostent *h;
	65
	66	h = gethostbyaddr(&addr, sizeof(addr), AF_INET);
	67	if (h == NULL)
	68	printf("?");
	69	else
	70	printf("%s", h->h_name);
	71	printf(" (%s) ", inet_ntoa(addr));
	72	}
	73
	74	static void print_line_no(int i)
	75	{
	76	printf("%3d ", -i);
	77	}
	78
	79	static const char *rtg_proto_str(enum mtrace_rtg_proto proto)
	80	{
	81	static char buf[80];
	82
	83	buf[0] = '\0';
	84
	85	switch (proto) {
	86	case MTRACE_RTG_PROTO_DVMRP:
	87	return "DVMRP";
	88	case MTRACE_RTG_PROTO_MOSPF:
	89	return "MOSPF";
	90	case MTRACE_RTG_PROTO_PIM:
	91	return "PIM";
	92	case MTRACE_RTG_PROTO_CBT:
	93	return "CBT";
	94	case MTRACE_RTG_PROTO_PIM_SPECIAL:
	95	return "PIM special";
	96	case MTRACE_RTG_PROTO_PIM_STATIC:
	97	return "PIM static";
	98	case MTRACE_RTG_PROTO_DVMRP_STATIC:
	99	return "DVMRP static";
	100	case MTRACE_RTG_PROTO_PIM_MBGP:
	101	return "PIM MBGP";
	102	case MTRACE_RTG_PROTO_CBT_SPECIAL:
	103	return "CBT special";
	104	case MTRACE_RTG_PROTO_CBT_STATIC:
	105	return "CBT static";
	106	case MTRACE_RTG_PROTO_PIM_ASSERT:
	107	return "PIM assert";
	108	default:
	109	sprintf(buf, "unknown protocol (%d)", proto);
	110	return buf;
	111	}
	112	}
	113
	114	static void print_rtg_proto(uint32_t rtg_proto)
	115	{
	116	printf("%s", rtg_proto_str(rtg_proto));
	117	}
	118
	119	static void print_fwd_ttl(uint32_t fwd_ttl)
	120	{
	121	printf("thresh^ %d", fwd_ttl);
	122	}
	123
	124	static const char *fwd_code_str(enum mtrace_fwd_code code)
	125	{
126	static char buf[80];
127
128	buf[0] = '\0';
129
130	switch (code) {
131	case MTRACE_FWD_CODE_NO_ERROR:
132	return "no error";
133	case MTRACE_FWD_CODE_WRONG_IF:
134	return "wrong interface";
135	case MTRACE_FWD_CODE_PRUNE_SENT:
136	return "prune sent";
137	case MTRACE_FWD_CODE_PRUNE_RCVD:
138	return "prune received";
139	case MTRACE_FWD_CODE_SCOPED:
140	return "scoped";
141	case MTRACE_FWD_CODE_NO_ROUTE:
142	return "no route";
143	case MTRACE_FWD_CODE_WRONG_LAST_HOP:
144	return "wrong last hop";
145	case MTRACE_FWD_CODE_NOT_FORWARDING:
146	return "not forwarding";
147	case MTRACE_FWD_CODE_REACHED_RP:
148	return "reached RP";
149	case MTRACE_FWD_CODE_RPF_IF:
150	return "RPF interface";
151	case MTRACE_FWD_CODE_NO_MULTICAST:
152	return "no multicast";
153	case MTRACE_FWD_CODE_INFO_HIDDEN:
154	return "info hidden";
155	case MTRACE_FWD_CODE_NO_SPACE:
156	return "no space";
157	case MTRACE_FWD_CODE_OLD_ROUTER:
158	return "old router";
159	case MTRACE_FWD_CODE_ADMIN_PROHIB:
160	return "admin. prohib.";
161	default:
162	sprintf(buf, "unknown fwd. code (%d)", code);
163	return buf;
164	}
165	}
166
167	static void print_fwd_code(uint32_t fwd_code)
168	{
169	printf("%s", fwd_code_str(fwd_code));
170	}
171
172	static void print_rsp(struct igmp_mtrace_rsp *rsp)
173	{
174	print_host(rsp->outgoing);
71e55fb2	175	if (rsp->fwd_code == 0 \|\| rsp->fwd_code == MTRACE_FWD_CODE_REACHED_RP) {
04a2eef3 MS	176	print_rtg_proto(rsp->rtg_proto);
04a2eef3 MS	177	printf(" ");
71e55fb2 MS	178	if (rsp->fwd_code == MTRACE_FWD_CODE_REACHED_RP)
	179	printf("(RP) ");
	180	if (rsp->rtg_proto == MTRACE_RTG_PROTO_PIM) {
	181	switch (rsp->src_mask) {
	182	case MTRACE_SRC_MASK_GROUP:
	183	printf("(*,G) ");
	184	break;
	185	case MTRACE_SRC_MASK_SOURCE:
	186	printf("(S,G) ");
	187	break;
	188	}
	189	}
04a2eef3 MS	190	print_fwd_ttl(rsp->fwd_ttl);
	191	} else {
	192	print_fwd_code(rsp->fwd_code);
	193	}
	194	printf("\n");
	195	}
	196
	197	static void print_dest(struct igmp_mtrace *mtrace)
	198	{
	199	print_line_no(0);
	200	print_host(mtrace->dst_addr);
	201	printf("\n");
	202	}
	203
	204	static void print_summary(struct igmp_mtrace *mtrace, int hops, long msec)
	205	{
	206	int i;
	207	int t = 0;
	208
	209	for (i = 0; i < hops; i++)
	210	t += mtrace->rsp[i].fwd_ttl;
	211
	212	printf("Round trip time %ld ms; total ttl of %d required.\n", msec, t);
	213	}
	214
	215	static void print_responses(struct igmp_mtrace *mtrace, int hops, long msec)
	216	{
	217	int i;
	218
	219	print_dest(mtrace);
	220
	221	for (i = 0; i < hops; i++) {
	222	print_line_no(i + 1);
	223	print_rsp(&mtrace->rsp[i]);
	224	}
	225	print_summary(mtrace, hops, msec);
	226	}
	227
4d9ad5dc MS	228	static int send_query(int fd, struct in_addr to_addr,
	229	struct igmp_mtrace *mtrace)
	230	{
	231	struct sockaddr_in to;
	232	socklen_t tolen;
	233	int sent;
	234
	235	memset(&to, 0, sizeof(to));
	236	to.sin_family = AF_INET;
	237	to.sin_addr = to_addr;
	238	tolen = sizeof(to);
	239
	240	sent = sendto(fd, (char )mtrace, sizeof(mtrace), MSG_DONTWAIT,
	241	(struct sockaddr *)&to, tolen);
	242
	243	if (sent < 1)
	244	return -1;
	245	return 0;
	246	}
	247
	248	static void print_query(struct igmp_mtrace *mtrace)
	249	{
	250	char src_str[INET_ADDRSTRLEN];
	251	char dst_str[INET_ADDRSTRLEN];
	252	char grp_str[INET_ADDRSTRLEN];
	253
	254	printf("* Mtrace from %s to %s via group %s\n",
	255	inet_ntop(AF_INET, &mtrace->src_addr, src_str, sizeof(src_str)),
	256	inet_ntop(AF_INET, &mtrace->dst_addr, dst_str, sizeof(dst_str)),
	257	inet_ntop(AF_INET, &mtrace->grp_addr, grp_str, sizeof(grp_str)));
	258	}
	259
04a2eef3	260	static int recv_response(int fd, int hops, struct igmp_mtrace mtracer)
4d9ad5dc MS	261	{
	262	int recvd;
	263	char mtrace_buf[IP_AND_MTRACE_BUF_LEN];
	264	struct ip *ip;
	265	struct igmp_mtrace *mtrace;
	266	int mtrace_len;
	267	int responses;
d7c0a89a	268	unsigned short sum;
4d9ad5dc MS	269
	270	recvd = recvfrom(fd, mtrace_buf, IP_AND_MTRACE_BUF_LEN, 0, NULL, 0);
	271
	272	if (recvd < 1) {
	273	fprintf(stderr, "recvfrom error: %s\n", strerror(errno));
	274	return -1;
	275	}
	276
	277	if (recvd < (int)sizeof(struct ip)) {
	278	fprintf(stderr, "no ip header\n");
	279	return -1;
	280	}
	281
	282	ip = (struct ip *)mtrace_buf;
	283
	284	if (ip->ip_v != 4) {
	285	fprintf(stderr, "IP not version 4\n");
	286	return -1;
	287	}
	288
	289	sum = ip->ip_sum;
	290	ip->ip_sum = 0;
	291
	292	if (sum != in_cksum(ip, ip->ip_hl * 4))
	293	return -1;
	294
	295	mtrace = (struct igmp_mtrace )(mtrace_buf + (4 ip->ip_hl));
	296
	297	mtrace_len = ntohs(ip->ip_len) - ip->ip_hl * 4;
	298
	299	if (mtrace_len < (int)MTRACE_HDR_SIZE)
	300	return -1;
	301
	302	sum = mtrace->checksum;
	303	mtrace->checksum = 0;
	304	if (sum != in_cksum(mtrace, mtrace_len)) {
	305	fprintf(stderr, "mtrace checksum wrong\n");
	306	return -1;
	307	}
	308
	309	if (mtrace->type != PIM_IGMP_MTRACE_RESPONSE)
	310	return -1;
	311
	312
	313	responses = mtrace_len - sizeof(struct igmp_mtrace);
	314	responses /= sizeof(struct igmp_mtrace_rsp);
	315
04a2eef3 MS	316	if (responses > MTRACE_MAX_HOPS) {
	317	fprintf(stderr, "mtrace too large\n");
	318	return -1;
	319	}
4d9ad5dc MS	320
	321	if (hops)
	322	*hops = responses;
	323
04a2eef3 MS	324	if (mtracer)
04a2eef3 MS	325	memcpy(mtracer, mtrace, mtrace_len);
4d9ad5dc MS	326
	327	return 0;
	328	}
	329
04a2eef3 MS	330	static int wait_for_response(int fd, int hops, struct igmp_mtrace mtrace,
04a2eef3 MS	331	long *ret_msec)
4d9ad5dc MS	332	{
	333	fd_set readfds;
	334	struct timeval timeout;
	335	int ret = -1;
	336	long msec, rmsec, tmsec;
	337
	338	FD_ZERO(&readfds);
	339	FD_SET(fd, &readfds);
	340
	341	memset(&timeout, 0, sizeof(timeout));
	342
	343	timeout.tv_sec = MTRACE_TIMEOUT;
	344
	345	tmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	346	do {
	347	ret = select(fd + 1, &readfds, NULL, NULL, &timeout);
	348	if (ret <= 0)
	349	return ret;
	350	rmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	351	msec = tmsec - rmsec;
04a2eef3 MS	352	} while (recv_response(fd, hops, mtrace) != 0);
	353
	354	if (ret_msec)
	355	*ret_msec = msec;
4d9ad5dc MS	356
	357	return ret;
	358	}
	359
04a2eef3 MS	360	static bool check_end(struct igmp_mtrace *mtrace, int hops)
	361	{
	362	return mtrace->src_addr.s_addr == mtrace->rsp[hops - 1].prev_hop.s_addr;
	363	}
	364
4d9ad5dc MS	365	int main(int argc, char *const argv[])
	366	{
	367	struct in_addr mc_source;
71e55fb2	368	struct in_addr mc_group;
4d9ad5dc MS	369	struct in_addr iface_addr;
	370	struct in_addr gw_addr;
	371	struct in_addr mtrace_addr;
	372	struct igmp_mtrace mtrace;
04a2eef3	373	struct igmp_mtrace *mtracep;
4d9ad5dc MS	374	int hops = 255;
	375	int rhops;
	376	int maxhops = 255;
	377	int perhop = 3;
	378	int ifindex;
	379	int unicast = 1;
	380	int ttl = 64;
	381	int fd = -1;
	382	int ret = -1;
	383	int c;
04a2eef3	384	long msec;
4d9ad5dc MS	385	int i, j;
4d9ad5dc MS	386	char ifname[IF_NAMESIZE];
04a2eef3	387	char mbuf[MTRACE_BUF_LEN];
71e55fb2	388	bool not_group;
4d9ad5dc MS	389
	390	mtrace_addr.s_addr = inet_addr("224.0.1.32");
	391
	392	uid_t uid = getuid();
	393
	394	if (uid != 0) {
	395	printf("must run as root\n");
	396	exit(EXIT_FAILURE);
	397	}
	398
	399	if (argc <= 0)
	400	progname = "mtracebis";
	401	else
	402	progname = argv[0];
	403
71e55fb2	404	if (argc != 2 && argc != 3) {
4d9ad5dc MS	405	usage();
	406	exit(EXIT_FAILURE);
	407	}
	408
	409	while (1) {
	410	static struct option long_options[] = {
	411	{"help", no_argument, 0, 'h'},
	412	{"version", no_argument, 0, 'v'},
996c9314	413	{0, 0, 0, 0}};
4d9ad5dc MS	414	int option_index = 0;
	415
	416	c = getopt_long(argc, argv, "vh", long_options, &option_index);
	417
	418	if (c == -1)
	419	break;
	420
	421	switch (c) {
	422	case 'h':
	423	usage();
	424	exit(0);
	425	case 'v':
	426	version();
	427	exit(0);
	428	default:
	429	usage();
	430	exit(EXIT_FAILURE);
	431	}
	432	}
	433	if (inet_pton(AF_INET, argv[1], &mc_source) != 1) {
	434	usage();
71e55fb2	435	fprintf(stderr, "%s: %s is not a valid IPv4 address\n", argv[0],
4d9ad5dc MS	436	argv[1]);
	437	exit(EXIT_FAILURE);
	438	}
	439
71e55fb2 MS	440	mc_group.s_addr = 0;
	441	not_group = false;
	442
	443	if (argc == 3) {
	444	if (inet_pton(AF_INET, argv[2], &mc_group) != 1)
	445	not_group = true;
	446	if (!not_group && !IPV4_CLASS_DE(ntohl(mc_group.s_addr)))
	447	not_group = true;
	448	}
	449
	450	if (not_group) {
	451	usage();
	452	fprintf(stderr, "%s: %s is not a valid IPv4 group address\n",
	453	argv[0], argv[2]);
	454	exit(EXIT_FAILURE);
	455	}
	456
4d9ad5dc MS	457	ifindex = routeget(mc_source, &iface_addr, &gw_addr);
	458	if (ifindex < 0) {
	459	fprintf(stderr, "%s: failed to get route to source %s\n",
	460	argv[0], argv[1]);
	461	exit(EXIT_FAILURE);
	462	}
	463
	464	if (if_indextoname(ifindex, ifname) == NULL) {
	465	fprintf(stderr, "%s: if_indextoname error: %s\n", argv[0],
	466	strerror(errno));
	467	exit(EXIT_FAILURE);
	468	}
	469
	470	/* zero mtrace struct */
	471	memset((char *)&mtrace, 0, sizeof(mtrace));
	472
	473	/* set up query */
	474	mtrace.type = PIM_IGMP_MTRACE_QUERY_REQUEST;
	475	mtrace.hops = hops;
	476	mtrace.checksum = 0;
71e55fb2	477	mtrace.grp_addr = mc_group;
4d9ad5dc MS	478	mtrace.src_addr = mc_source;
	479	mtrace.dst_addr = iface_addr;
	480	mtrace.rsp_addr = unicast ? iface_addr : mtrace_addr;
	481	mtrace.rsp_ttl = ttl;
	482	mtrace.qry_id = 0xffffff & time(NULL);
	483
	484	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
	485
	486	fd = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP);
	487
	488	if (fd < 1) {
	489	fprintf(stderr, "%s: socket error: %s\n", argv[0],
	490	strerror(errno));
	491	exit(EXIT_FAILURE);
	492	}
	493
	494	ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
	495	strlen(ifname));
	496
	497	if (ret < 0) {
	498	fprintf(stderr, "%s: setsockopt error: %s\n", argv[0],
	499	strerror(errno));
	500	ret = EXIT_FAILURE;
	501	goto close_fd;
	502	}
	503
	504	print_query(&mtrace);
	505	if (send_query(fd, gw_addr, &mtrace) < 0) {
	506	fprintf(stderr, "%s: sendto error: %s\n", argv[0],
	507	strerror(errno));
	508	ret = EXIT_FAILURE;
	509	goto close_fd;
	510	}
	511	printf("Querying full reverse path...\n");
04a2eef3 MS	512	mtracep = (struct igmp_mtrace *)mbuf;
04a2eef3 MS	513	ret = wait_for_response(fd, &rhops, mtracep, &msec);
4d9ad5dc	514	if (ret > 0) {
04a2eef3	515	print_responses(mtracep, rhops, msec);
4d9ad5dc MS	516	ret = 0;
	517	goto close_fd;
	518	}
	519	if (ret < 0) {
	520	fprintf(stderr, "%s: select error: %s\n", argv[0],
	521	strerror(errno));
	522	ret = EXIT_FAILURE;
	523	goto close_fd;
	524	}
	525	printf(" * ");
	526	printf("switching to hop-by-hop:\n");
04a2eef3	527	print_dest(&mtrace);
4d9ad5dc	528	for (i = 1; i < maxhops; i++) {
04a2eef3	529	print_line_no(i);
4d9ad5dc MS	530	mtrace.hops = i;
	531	for (j = 0; j < perhop; j++) {
	532	mtrace.qry_id++;
	533	mtrace.checksum = 0;
	534	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
	535	if (send_query(fd, gw_addr, &mtrace) < 0) {
	536	fprintf(stderr, "%s: sendto error: %s\n",
	537	argv[0], strerror(errno));
	538	ret = EXIT_FAILURE;
	539	goto close_fd;
	540	}
04a2eef3	541	ret = wait_for_response(fd, &rhops, mtracep, &msec);
4d9ad5dc	542	if (ret > 0) {
04a2eef3 MS	543	if (check_end(mtracep, rhops)) {
	544	print_rsp(&mtracep->rsp[rhops - 1]);
	545	print_summary(mtracep, rhops, msec);
	546	ret = 0;
	547	goto close_fd;
	548	}
4d9ad5dc	549	if (i > rhops) {
04a2eef3	550	printf(" * ...giving up.\n");
4d9ad5dc MS	551	ret = 0;
	552	goto close_fd;
	553	}
04a2eef3	554	print_rsp(&mtracep->rsp[rhops - 1]);
4d9ad5dc MS	555	break;
	556	}
	557	printf(" *");
	558	}
	559	if (ret <= 0)
	560	printf("\n");
	561	}
	562	ret = 0;
	563	close_fd:
	564	close(fd);
	565	exit(ret);
	566	}
	567
	568	#else /* __linux__ */
	569
	570	#include <stdio.h>
	571	#include <stdlib.h>
	572
	573	int main(int argc, char *argv[])
	574	{
	575	printf("%s implemented only for GNU/Linux\n", argv[0]);
	576	exit(0);
	577	}
	578
	579	#endif /* __linux__ */