[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 HAVE_CONFIG_H
#include "config.h"
#endif

#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;
	size_t mtrace_off;
	size_t ip_len;

	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;

	/* Header overflow check */
	mtrace_off = 4 * ip->ip_hl;
	if (mtrace_off > MTRACE_BUF_LEN)
		return -1;

	/* Underflow/overflow check */
	ip_len = ntohs(ip->ip_len);
	if (ip_len < mtrace_off || ip_len < MTRACE_HDR_SIZE
	    || ip_len > MTRACE_BUF_LEN)
		return -1;

	mtrace_len = ip_len - mtrace_off;
	mtrace = (struct igmp_mtrace *)(mtrace_buf + mtrace_off);

	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;
	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
b45ac5f5 DL	20	#ifdef HAVE_CONFIG_H
	21	#include "config.h"
	22	#endif
	23
4d9ad5dc MS	24	#ifdef __linux__
	25
	26	#include "pim_igmp_mtrace.h"
	27
	28	#include "checksum.h"
71e55fb2	29	#include "prefix.h"
4d9ad5dc MS	30	#include "mtracebis_routeget.h"
	31
	32	#include <sys/select.h>
	33	#include <netinet/in.h>
	34	#include <arpa/inet.h>
	35	#include <unistd.h>
	36	#include <sys/types.h>
	37	#include <sys/time.h>
	38	#include <stdio.h>
	39	#include <stdlib.h>
	40	#include <string.h>
	41	#include <time.h>
	42	#include <net/if.h>
5b02bd3a DS	43	#include <unistd.h>
5b02bd3a DS	44	#include <getopt.h>
04a2eef3	45	#include <netdb.h>
4d9ad5dc MS	46
	47	#define MTRACEBIS_VERSION "0.1"
	48	#define MTRACE_TIMEOUT (5)
	49
	50	#define IP_HDR_LEN (sizeof(struct ip))
	51	#define IP_RA_LEN (4)
	52	#define MTRACE_BUF_LEN (MTRACE_HDR_SIZE + (MTRACE_MAX_HOPS * MTRACE_RSP_SIZE))
	53	#define IP_AND_MTRACE_BUF_LEN (IP_HDR_LEN + IP_RA_LEN + MTRACE_BUF_LEN)
	54
	55	static const char *progname;
	56	static void usage(void)
	57	{
71e55fb2 MS	58	fprintf(stderr, "Usage : %s <multicast source> [<multicast group>]\n",
71e55fb2 MS	59	progname);
4d9ad5dc MS	60	}
	61	static void version(void)
	62	{
	63	fprintf(stderr, "%s %s\n", progname, MTRACEBIS_VERSION);
	64	}
	65
04a2eef3 MS	66	static void print_host(struct in_addr addr)
	67	{
	68	struct hostent *h;
	69
	70	h = gethostbyaddr(&addr, sizeof(addr), AF_INET);
	71	if (h == NULL)
	72	printf("?");
	73	else
	74	printf("%s", h->h_name);
	75	printf(" (%s) ", inet_ntoa(addr));
	76	}
	77
	78	static void print_line_no(int i)
	79	{
	80	printf("%3d ", -i);
	81	}
	82
	83	static const char *rtg_proto_str(enum mtrace_rtg_proto proto)
	84	{
	85	static char buf[80];
	86
	87	buf[0] = '\0';
	88
	89	switch (proto) {
	90	case MTRACE_RTG_PROTO_DVMRP:
	91	return "DVMRP";
	92	case MTRACE_RTG_PROTO_MOSPF:
	93	return "MOSPF";
	94	case MTRACE_RTG_PROTO_PIM:
	95	return "PIM";
	96	case MTRACE_RTG_PROTO_CBT:
	97	return "CBT";
	98	case MTRACE_RTG_PROTO_PIM_SPECIAL:
	99	return "PIM special";
	100	case MTRACE_RTG_PROTO_PIM_STATIC:
	101	return "PIM static";
	102	case MTRACE_RTG_PROTO_DVMRP_STATIC:
	103	return "DVMRP static";
	104	case MTRACE_RTG_PROTO_PIM_MBGP:
	105	return "PIM MBGP";
	106	case MTRACE_RTG_PROTO_CBT_SPECIAL:
	107	return "CBT special";
	108	case MTRACE_RTG_PROTO_CBT_STATIC:
	109	return "CBT static";
	110	case MTRACE_RTG_PROTO_PIM_ASSERT:
	111	return "PIM assert";
	112	default:
	113	sprintf(buf, "unknown protocol (%d)", proto);
	114	return buf;
	115	}
	116	}
	117
	118	static void print_rtg_proto(uint32_t rtg_proto)
	119	{
	120	printf("%s", rtg_proto_str(rtg_proto));
	121	}
	122
	123	static void print_fwd_ttl(uint32_t fwd_ttl)
	124	{
	125	printf("thresh^ %d", fwd_ttl);
	126	}
	127
	128	static const char *fwd_code_str(enum mtrace_fwd_code code)
	129	{
130	static char buf[80];
131
132	buf[0] = '\0';
133
134	switch (code) {
135	case MTRACE_FWD_CODE_NO_ERROR:
136	return "no error";
137	case MTRACE_FWD_CODE_WRONG_IF:
138	return "wrong interface";
139	case MTRACE_FWD_CODE_PRUNE_SENT:
140	return "prune sent";
141	case MTRACE_FWD_CODE_PRUNE_RCVD:
142	return "prune received";
143	case MTRACE_FWD_CODE_SCOPED:
144	return "scoped";
145	case MTRACE_FWD_CODE_NO_ROUTE:
146	return "no route";
147	case MTRACE_FWD_CODE_WRONG_LAST_HOP:
148	return "wrong last hop";
149	case MTRACE_FWD_CODE_NOT_FORWARDING:
150	return "not forwarding";
151	case MTRACE_FWD_CODE_REACHED_RP:
152	return "reached RP";
153	case MTRACE_FWD_CODE_RPF_IF:
154	return "RPF interface";
155	case MTRACE_FWD_CODE_NO_MULTICAST:
156	return "no multicast";
157	case MTRACE_FWD_CODE_INFO_HIDDEN:
158	return "info hidden";
159	case MTRACE_FWD_CODE_NO_SPACE:
160	return "no space";
161	case MTRACE_FWD_CODE_OLD_ROUTER:
162	return "old router";
163	case MTRACE_FWD_CODE_ADMIN_PROHIB:
164	return "admin. prohib.";
165	default:
166	sprintf(buf, "unknown fwd. code (%d)", code);
167	return buf;
168	}
169	}
170
171	static void print_fwd_code(uint32_t fwd_code)
172	{
173	printf("%s", fwd_code_str(fwd_code));
174	}
175
176	static void print_rsp(struct igmp_mtrace_rsp *rsp)
177	{
178	print_host(rsp->outgoing);
71e55fb2	179	if (rsp->fwd_code == 0 \|\| rsp->fwd_code == MTRACE_FWD_CODE_REACHED_RP) {
04a2eef3 MS	180	print_rtg_proto(rsp->rtg_proto);
04a2eef3 MS	181	printf(" ");
71e55fb2 MS	182	if (rsp->fwd_code == MTRACE_FWD_CODE_REACHED_RP)
	183	printf("(RP) ");
	184	if (rsp->rtg_proto == MTRACE_RTG_PROTO_PIM) {
	185	switch (rsp->src_mask) {
	186	case MTRACE_SRC_MASK_GROUP:
	187	printf("(*,G) ");
	188	break;
	189	case MTRACE_SRC_MASK_SOURCE:
	190	printf("(S,G) ");
	191	break;
	192	}
	193	}
04a2eef3 MS	194	print_fwd_ttl(rsp->fwd_ttl);
	195	} else {
	196	print_fwd_code(rsp->fwd_code);
	197	}
	198	printf("\n");
	199	}
	200
	201	static void print_dest(struct igmp_mtrace *mtrace)
	202	{
	203	print_line_no(0);
	204	print_host(mtrace->dst_addr);
	205	printf("\n");
	206	}
	207
	208	static void print_summary(struct igmp_mtrace *mtrace, int hops, long msec)
	209	{
	210	int i;
	211	int t = 0;
	212
	213	for (i = 0; i < hops; i++)
	214	t += mtrace->rsp[i].fwd_ttl;
	215
	216	printf("Round trip time %ld ms; total ttl of %d required.\n", msec, t);
	217	}
	218
	219	static void print_responses(struct igmp_mtrace *mtrace, int hops, long msec)
	220	{
	221	int i;
	222
	223	print_dest(mtrace);
	224
	225	for (i = 0; i < hops; i++) {
	226	print_line_no(i + 1);
	227	print_rsp(&mtrace->rsp[i]);
	228	}
	229	print_summary(mtrace, hops, msec);
	230	}
	231
4d9ad5dc MS	232	static int send_query(int fd, struct in_addr to_addr,
	233	struct igmp_mtrace *mtrace)
	234	{
	235	struct sockaddr_in to;
	236	socklen_t tolen;
	237	int sent;
	238
	239	memset(&to, 0, sizeof(to));
	240	to.sin_family = AF_INET;
	241	to.sin_addr = to_addr;
	242	tolen = sizeof(to);
	243
	244	sent = sendto(fd, (char )mtrace, sizeof(mtrace), MSG_DONTWAIT,
	245	(struct sockaddr *)&to, tolen);
	246
	247	if (sent < 1)
	248	return -1;
	249	return 0;
	250	}
	251
	252	static void print_query(struct igmp_mtrace *mtrace)
	253	{
	254	char src_str[INET_ADDRSTRLEN];
	255	char dst_str[INET_ADDRSTRLEN];
	256	char grp_str[INET_ADDRSTRLEN];
	257
	258	printf("* Mtrace from %s to %s via group %s\n",
	259	inet_ntop(AF_INET, &mtrace->src_addr, src_str, sizeof(src_str)),
	260	inet_ntop(AF_INET, &mtrace->dst_addr, dst_str, sizeof(dst_str)),
	261	inet_ntop(AF_INET, &mtrace->grp_addr, grp_str, sizeof(grp_str)));
	262	}
	263
04a2eef3	264	static int recv_response(int fd, int hops, struct igmp_mtrace mtracer)
4d9ad5dc MS	265	{
	266	int recvd;
	267	char mtrace_buf[IP_AND_MTRACE_BUF_LEN];
	268	struct ip *ip;
	269	struct igmp_mtrace *mtrace;
	270	int mtrace_len;
	271	int responses;
d7c0a89a	272	unsigned short sum;
813099f0	273	size_t mtrace_off;
813099f0	274	size_t ip_len;
4d9ad5dc MS	275
	276	recvd = recvfrom(fd, mtrace_buf, IP_AND_MTRACE_BUF_LEN, 0, NULL, 0);
	277
	278	if (recvd < 1) {
	279	fprintf(stderr, "recvfrom error: %s\n", strerror(errno));
	280	return -1;
	281	}
	282
	283	if (recvd < (int)sizeof(struct ip)) {
	284	fprintf(stderr, "no ip header\n");
	285	return -1;
	286	}
	287
	288	ip = (struct ip *)mtrace_buf;
	289
	290	if (ip->ip_v != 4) {
	291	fprintf(stderr, "IP not version 4\n");
	292	return -1;
	293	}
	294
	295	sum = ip->ip_sum;
	296	ip->ip_sum = 0;
	297
	298	if (sum != in_cksum(ip, ip->ip_hl * 4))
	299	return -1;
	300
813099f0	301	/* Header overflow check */
	302	mtrace_off = 4 * ip->ip_hl;
	303	if (mtrace_off > MTRACE_BUF_LEN)
18e994a0	304	return -1;
18e994a0	305
813099f0	306	/* Underflow/overflow check */
	307	ip_len = ntohs(ip->ip_len);
	308	if (ip_len < mtrace_off \|\| ip_len < MTRACE_HDR_SIZE
	309	\|\| ip_len > MTRACE_BUF_LEN)
4d9ad5dc MS	310	return -1;
4d9ad5dc MS	311
813099f0	312	mtrace_len = ip_len - mtrace_off;
813099f0	313	mtrace = (struct igmp_mtrace *)(mtrace_buf + mtrace_off);
d94023d8	314
4d9ad5dc MS	315	sum = mtrace->checksum;
	316	mtrace->checksum = 0;
	317	if (sum != in_cksum(mtrace, mtrace_len)) {
	318	fprintf(stderr, "mtrace checksum wrong\n");
	319	return -1;
	320	}
	321
	322	if (mtrace->type != PIM_IGMP_MTRACE_RESPONSE)
	323	return -1;
	324
	325
	326	responses = mtrace_len - sizeof(struct igmp_mtrace);
	327	responses /= sizeof(struct igmp_mtrace_rsp);
	328
04a2eef3 MS	329	if (responses > MTRACE_MAX_HOPS) {
	330	fprintf(stderr, "mtrace too large\n");
	331	return -1;
	332	}
4d9ad5dc MS	333
	334	if (hops)
	335	*hops = responses;
	336
04a2eef3 MS	337	if (mtracer)
04a2eef3 MS	338	memcpy(mtracer, mtrace, mtrace_len);
4d9ad5dc MS	339
	340	return 0;
	341	}
	342
04a2eef3 MS	343	static int wait_for_response(int fd, int hops, struct igmp_mtrace mtrace,
04a2eef3 MS	344	long *ret_msec)
4d9ad5dc MS	345	{
	346	fd_set readfds;
	347	struct timeval timeout;
a2b6e694	348	int ret;
4d9ad5dc MS	349	long msec, rmsec, tmsec;
	350
	351	FD_ZERO(&readfds);
	352	FD_SET(fd, &readfds);
	353
	354	memset(&timeout, 0, sizeof(timeout));
	355
	356	timeout.tv_sec = MTRACE_TIMEOUT;
	357
	358	tmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	359	do {
	360	ret = select(fd + 1, &readfds, NULL, NULL, &timeout);
	361	if (ret <= 0)
	362	return ret;
	363	rmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	364	msec = tmsec - rmsec;
04a2eef3 MS	365	} while (recv_response(fd, hops, mtrace) != 0);
	366
	367	if (ret_msec)
	368	*ret_msec = msec;
4d9ad5dc MS	369
	370	return ret;
	371	}
	372
04a2eef3 MS	373	static bool check_end(struct igmp_mtrace *mtrace, int hops)
	374	{
	375	return mtrace->src_addr.s_addr == mtrace->rsp[hops - 1].prev_hop.s_addr;
	376	}
	377
4d9ad5dc MS	378	int main(int argc, char *const argv[])
	379	{
	380	struct in_addr mc_source;
71e55fb2	381	struct in_addr mc_group;
4d9ad5dc MS	382	struct in_addr iface_addr;
	383	struct in_addr gw_addr;
	384	struct in_addr mtrace_addr;
	385	struct igmp_mtrace mtrace;
04a2eef3	386	struct igmp_mtrace *mtracep;
4d9ad5dc MS	387	int hops = 255;
	388	int rhops;
	389	int maxhops = 255;
	390	int perhop = 3;
	391	int ifindex;
	392	int unicast = 1;
	393	int ttl = 64;
	394	int fd = -1;
	395	int ret = -1;
	396	int c;
04a2eef3	397	long msec;
4d9ad5dc MS	398	int i, j;
4d9ad5dc MS	399	char ifname[IF_NAMESIZE];
04a2eef3	400	char mbuf[MTRACE_BUF_LEN];
71e55fb2	401	bool not_group;
4d9ad5dc MS	402
	403	mtrace_addr.s_addr = inet_addr("224.0.1.32");
	404
	405	uid_t uid = getuid();
	406
	407	if (uid != 0) {
	408	printf("must run as root\n");
	409	exit(EXIT_FAILURE);
	410	}
	411
	412	if (argc <= 0)
	413	progname = "mtracebis";
	414	else
	415	progname = argv[0];
	416
71e55fb2	417	if (argc != 2 && argc != 3) {
4d9ad5dc MS	418	usage();
	419	exit(EXIT_FAILURE);
	420	}
	421
	422	while (1) {
	423	static struct option long_options[] = {
	424	{"help", no_argument, 0, 'h'},
	425	{"version", no_argument, 0, 'v'},
996c9314	426	{0, 0, 0, 0}};
4d9ad5dc MS	427	int option_index = 0;
	428
	429	c = getopt_long(argc, argv, "vh", long_options, &option_index);
	430
	431	if (c == -1)
	432	break;
	433
	434	switch (c) {
	435	case 'h':
	436	usage();
	437	exit(0);
	438	case 'v':
	439	version();
	440	exit(0);
	441	default:
	442	usage();
	443	exit(EXIT_FAILURE);
	444	}
	445	}
	446	if (inet_pton(AF_INET, argv[1], &mc_source) != 1) {
	447	usage();
71e55fb2	448	fprintf(stderr, "%s: %s is not a valid IPv4 address\n", argv[0],
4d9ad5dc MS	449	argv[1]);
	450	exit(EXIT_FAILURE);
	451	}
	452
71e55fb2 MS	453	mc_group.s_addr = 0;
	454	not_group = false;
	455
	456	if (argc == 3) {
	457	if (inet_pton(AF_INET, argv[2], &mc_group) != 1)
	458	not_group = true;
	459	if (!not_group && !IPV4_CLASS_DE(ntohl(mc_group.s_addr)))
	460	not_group = true;
	461	}
	462
	463	if (not_group) {
	464	usage();
	465	fprintf(stderr, "%s: %s is not a valid IPv4 group address\n",
	466	argv[0], argv[2]);
	467	exit(EXIT_FAILURE);
	468	}
	469
4d9ad5dc MS	470	ifindex = routeget(mc_source, &iface_addr, &gw_addr);
	471	if (ifindex < 0) {
	472	fprintf(stderr, "%s: failed to get route to source %s\n",
	473	argv[0], argv[1]);
	474	exit(EXIT_FAILURE);
	475	}
	476
	477	if (if_indextoname(ifindex, ifname) == NULL) {
	478	fprintf(stderr, "%s: if_indextoname error: %s\n", argv[0],
	479	strerror(errno));
	480	exit(EXIT_FAILURE);
	481	}
	482
	483	/* zero mtrace struct */
	484	memset((char *)&mtrace, 0, sizeof(mtrace));
	485
	486	/* set up query */
	487	mtrace.type = PIM_IGMP_MTRACE_QUERY_REQUEST;
	488	mtrace.hops = hops;
	489	mtrace.checksum = 0;
71e55fb2	490	mtrace.grp_addr = mc_group;
4d9ad5dc MS	491	mtrace.src_addr = mc_source;
	492	mtrace.dst_addr = iface_addr;
	493	mtrace.rsp_addr = unicast ? iface_addr : mtrace_addr;
	494	mtrace.rsp_ttl = ttl;
	495	mtrace.qry_id = 0xffffff & time(NULL);
	496
	497	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
	498
	499	fd = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP);
	500
	501	if (fd < 1) {
	502	fprintf(stderr, "%s: socket error: %s\n", argv[0],
	503	strerror(errno));
	504	exit(EXIT_FAILURE);
	505	}
	506
	507	ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
	508	strlen(ifname));
	509
	510	if (ret < 0) {
	511	fprintf(stderr, "%s: setsockopt error: %s\n", argv[0],
	512	strerror(errno));
	513	ret = EXIT_FAILURE;
	514	goto close_fd;
	515	}
	516
	517	print_query(&mtrace);
	518	if (send_query(fd, gw_addr, &mtrace) < 0) {
	519	fprintf(stderr, "%s: sendto error: %s\n", argv[0],
	520	strerror(errno));
	521	ret = EXIT_FAILURE;
	522	goto close_fd;
	523	}
	524	printf("Querying full reverse path...\n");
04a2eef3 MS	525	mtracep = (struct igmp_mtrace *)mbuf;
04a2eef3 MS	526	ret = wait_for_response(fd, &rhops, mtracep, &msec);
4d9ad5dc	527	if (ret > 0) {
04a2eef3	528	print_responses(mtracep, rhops, msec);
4d9ad5dc MS	529	ret = 0;
	530	goto close_fd;
	531	}
	532	if (ret < 0) {
	533	fprintf(stderr, "%s: select error: %s\n", argv[0],
	534	strerror(errno));
	535	ret = EXIT_FAILURE;
	536	goto close_fd;
	537	}
	538	printf(" * ");
	539	printf("switching to hop-by-hop:\n");
04a2eef3	540	print_dest(&mtrace);
4d9ad5dc	541	for (i = 1; i < maxhops; i++) {
04a2eef3	542	print_line_no(i);
4d9ad5dc MS	543	mtrace.hops = i;
	544	for (j = 0; j < perhop; j++) {
	545	mtrace.qry_id++;
	546	mtrace.checksum = 0;
	547	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
	548	if (send_query(fd, gw_addr, &mtrace) < 0) {
	549	fprintf(stderr, "%s: sendto error: %s\n",
	550	argv[0], strerror(errno));
	551	ret = EXIT_FAILURE;
	552	goto close_fd;
	553	}
04a2eef3	554	ret = wait_for_response(fd, &rhops, mtracep, &msec);
4d9ad5dc	555	if (ret > 0) {
04a2eef3 MS	556	if (check_end(mtracep, rhops)) {
	557	print_rsp(&mtracep->rsp[rhops - 1]);
	558	print_summary(mtracep, rhops, msec);
	559	ret = 0;
	560	goto close_fd;
	561	}
4d9ad5dc	562	if (i > rhops) {
04a2eef3	563	printf(" * ...giving up.\n");
4d9ad5dc MS	564	ret = 0;
	565	goto close_fd;
	566	}
04a2eef3	567	print_rsp(&mtracep->rsp[rhops - 1]);
4d9ad5dc MS	568	break;
	569	}
	570	printf(" *");
	571	}
	572	if (ret <= 0)
	573	printf("\n");
	574	}
	575	ret = 0;
	576	close_fd:
	577	close(fd);
	578	exit(ret);
	579	}
	580
	581	#else /* __linux__ */
	582
	583	#include <stdio.h>
	584	#include <stdlib.h>
	585
	586	int main(int argc, char *argv[])
	587	{
	588	printf("%s implemented only for GNU/Linux\n", argv[0]);
	589	exit(0);
	590	}
	591
	592	#endif /* __linux__ */