[mirror_frr.git] / pimd / mtracebis.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Multicast Traceroute for FRRouting
 * Copyright (C) 2018  Mladen Sablic
 */

#include <zebra.h>

#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;
	char buf[PREFIX_STRLEN];

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

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:
		snprintf(buf, sizeof(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:
		snprintf(buf, sizeof(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 = INADDR_ANY;
	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
acddc0ed	1	// SPDX-License-Identifier: GPL-2.0-or-later
4d9ad5dc MS	2	/*
	3	* Multicast Traceroute for FRRouting
	4	* Copyright (C) 2018 Mladen Sablic
4d9ad5dc MS	5	*/
4d9ad5dc MS	6
0ce5349f	7	#include <zebra.h>
b45ac5f5	8
4d9ad5dc MS	9	#ifdef __linux__
	10
	11	#include "pim_igmp_mtrace.h"
	12
	13	#include "checksum.h"
71e55fb2	14	#include "prefix.h"
4d9ad5dc	15	#include "mtracebis_routeget.h"
4d9ad5dc MS	16	#include <sys/select.h>
	17	#include <netinet/in.h>
	18	#include <arpa/inet.h>
	19	#include <unistd.h>
	20	#include <sys/types.h>
	21	#include <sys/time.h>
	22	#include <stdio.h>
	23	#include <stdlib.h>
	24	#include <string.h>
	25	#include <time.h>
	26	#include <net/if.h>
5b02bd3a DS	27	#include <unistd.h>
5b02bd3a DS	28	#include <getopt.h>
04a2eef3	29	#include <netdb.h>
4d9ad5dc MS	30
	31	#define MTRACEBIS_VERSION "0.1"
	32	#define MTRACE_TIMEOUT (5)
	33
	34	#define IP_HDR_LEN (sizeof(struct ip))
	35	#define IP_RA_LEN (4)
	36	#define MTRACE_BUF_LEN (MTRACE_HDR_SIZE + (MTRACE_MAX_HOPS * MTRACE_RSP_SIZE))
	37	#define IP_AND_MTRACE_BUF_LEN (IP_HDR_LEN + IP_RA_LEN + MTRACE_BUF_LEN)
	38
	39	static const char *progname;
	40	static void usage(void)
	41	{
71e55fb2 MS	42	fprintf(stderr, "Usage : %s <multicast source> [<multicast group>]\n",
71e55fb2 MS	43	progname);
4d9ad5dc MS	44	}
	45	static void version(void)
	46	{
	47	fprintf(stderr, "%s %s\n", progname, MTRACEBIS_VERSION);
	48	}
	49
04a2eef3 MS	50	static void print_host(struct in_addr addr)
	51	{
	52	struct hostent *h;
ee2bbf7c	53	char buf[PREFIX_STRLEN];
04a2eef3 MS	54
	55	h = gethostbyaddr(&addr, sizeof(addr), AF_INET);
	56	if (h == NULL)
	57	printf("?");
	58	else
	59	printf("%s", h->h_name);
ee2bbf7c	60	printf(" (%s) ", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
04a2eef3 MS	61	}
	62
	63	static void print_line_no(int i)
	64	{
	65	printf("%3d ", -i);
	66	}
	67
	68	static const char *rtg_proto_str(enum mtrace_rtg_proto proto)
	69	{
	70	static char buf[80];
	71
	72	buf[0] = '\0';
	73
	74	switch (proto) {
	75	case MTRACE_RTG_PROTO_DVMRP:
	76	return "DVMRP";
	77	case MTRACE_RTG_PROTO_MOSPF:
	78	return "MOSPF";
	79	case MTRACE_RTG_PROTO_PIM:
	80	return "PIM";
	81	case MTRACE_RTG_PROTO_CBT:
	82	return "CBT";
	83	case MTRACE_RTG_PROTO_PIM_SPECIAL:
	84	return "PIM special";
	85	case MTRACE_RTG_PROTO_PIM_STATIC:
	86	return "PIM static";
	87	case MTRACE_RTG_PROTO_DVMRP_STATIC:
	88	return "DVMRP static";
	89	case MTRACE_RTG_PROTO_PIM_MBGP:
	90	return "PIM MBGP";
	91	case MTRACE_RTG_PROTO_CBT_SPECIAL:
	92	return "CBT special";
	93	case MTRACE_RTG_PROTO_CBT_STATIC:
	94	return "CBT static";
	95	case MTRACE_RTG_PROTO_PIM_ASSERT:
	96	return "PIM assert";
	97	default:
772270f3	98	snprintf(buf, sizeof(buf), "unknown protocol (%d)", proto);
04a2eef3 MS	99	return buf;
	100	}
	101	}
	102
	103	static void print_rtg_proto(uint32_t rtg_proto)
	104	{
	105	printf("%s", rtg_proto_str(rtg_proto));
	106	}
	107
	108	static void print_fwd_ttl(uint32_t fwd_ttl)
	109	{
	110	printf("thresh^ %d", fwd_ttl);
	111	}
	112
	113	static const char *fwd_code_str(enum mtrace_fwd_code code)
	114	{
	115	static char buf[80];
	116
	117	buf[0] = '\0';
	118
	119	switch (code) {
	120	case MTRACE_FWD_CODE_NO_ERROR:
	121	return "no error";
	122	case MTRACE_FWD_CODE_WRONG_IF:
	123	return "wrong interface";
	124	case MTRACE_FWD_CODE_PRUNE_SENT:
	125	return "prune sent";
	126	case MTRACE_FWD_CODE_PRUNE_RCVD:
	127	return "prune received";
	128	case MTRACE_FWD_CODE_SCOPED:
	129	return "scoped";
	130	case MTRACE_FWD_CODE_NO_ROUTE:
	131	return "no route";
	132	case MTRACE_FWD_CODE_WRONG_LAST_HOP:
	133	return "wrong last hop";
	134	case MTRACE_FWD_CODE_NOT_FORWARDING:
	135	return "not forwarding";
	136	case MTRACE_FWD_CODE_REACHED_RP:
	137	return "reached RP";
	138	case MTRACE_FWD_CODE_RPF_IF:
	139	return "RPF interface";
	140	case MTRACE_FWD_CODE_NO_MULTICAST:
	141	return "no multicast";
	142	case MTRACE_FWD_CODE_INFO_HIDDEN:
	143	return "info hidden";
	144	case MTRACE_FWD_CODE_NO_SPACE:
	145	return "no space";
	146	case MTRACE_FWD_CODE_OLD_ROUTER:
	147	return "old router";
	148	case MTRACE_FWD_CODE_ADMIN_PROHIB:
	149	return "admin. prohib.";
	150	default:
772270f3	151	snprintf(buf, sizeof(buf), "unknown fwd. code (%d)", code);
04a2eef3 MS	152	return buf;
	153	}
	154	}
	155
	156	static void print_fwd_code(uint32_t fwd_code)
	157	{
	158	printf("%s", fwd_code_str(fwd_code));
	159	}
	160
	161	static void print_rsp(struct igmp_mtrace_rsp *rsp)
	162	{
	163	print_host(rsp->outgoing);
71e55fb2	164	if (rsp->fwd_code == 0 \|\| rsp->fwd_code == MTRACE_FWD_CODE_REACHED_RP) {
04a2eef3 MS	165	print_rtg_proto(rsp->rtg_proto);
04a2eef3 MS	166	printf(" ");
71e55fb2 MS	167	if (rsp->fwd_code == MTRACE_FWD_CODE_REACHED_RP)
	168	printf("(RP) ");
	169	if (rsp->rtg_proto == MTRACE_RTG_PROTO_PIM) {
	170	switch (rsp->src_mask) {
	171	case MTRACE_SRC_MASK_GROUP:
	172	printf("(*,G) ");
	173	break;
	174	case MTRACE_SRC_MASK_SOURCE:
	175	printf("(S,G) ");
	176	break;
	177	}
	178	}
04a2eef3 MS	179	print_fwd_ttl(rsp->fwd_ttl);
	180	} else {
	181	print_fwd_code(rsp->fwd_code);
	182	}
	183	printf("\n");
	184	}
	185
	186	static void print_dest(struct igmp_mtrace *mtrace)
	187	{
	188	print_line_no(0);
	189	print_host(mtrace->dst_addr);
	190	printf("\n");
	191	}
	192
	193	static void print_summary(struct igmp_mtrace *mtrace, int hops, long msec)
	194	{
	195	int i;
	196	int t = 0;
	197
	198	for (i = 0; i < hops; i++)
	199	t += mtrace->rsp[i].fwd_ttl;
	200
	201	printf("Round trip time %ld ms; total ttl of %d required.\n", msec, t);
	202	}
	203
	204	static void print_responses(struct igmp_mtrace *mtrace, int hops, long msec)
	205	{
	206	int i;
	207
	208	print_dest(mtrace);
	209
	210	for (i = 0; i < hops; i++) {
	211	print_line_no(i + 1);
	212	print_rsp(&mtrace->rsp[i]);
	213	}
	214	print_summary(mtrace, hops, msec);
	215	}
	216
4d9ad5dc MS	217	static int send_query(int fd, struct in_addr to_addr,
	218	struct igmp_mtrace *mtrace)
	219	{
	220	struct sockaddr_in to;
	221	socklen_t tolen;
	222	int sent;
	223
	224	memset(&to, 0, sizeof(to));
	225	to.sin_family = AF_INET;
	226	to.sin_addr = to_addr;
	227	tolen = sizeof(to);
	228
	229	sent = sendto(fd, (char )mtrace, sizeof(mtrace), MSG_DONTWAIT,
	230	(struct sockaddr *)&to, tolen);
	231
	232	if (sent < 1)
	233	return -1;
	234	return 0;
	235	}
	236
	237	static void print_query(struct igmp_mtrace *mtrace)
	238	{
	239	char src_str[INET_ADDRSTRLEN];
	240	char dst_str[INET_ADDRSTRLEN];
	241	char grp_str[INET_ADDRSTRLEN];
	242
	243	printf("* Mtrace from %s to %s via group %s\n",
	244	inet_ntop(AF_INET, &mtrace->src_addr, src_str, sizeof(src_str)),
	245	inet_ntop(AF_INET, &mtrace->dst_addr, dst_str, sizeof(dst_str)),
	246	inet_ntop(AF_INET, &mtrace->grp_addr, grp_str, sizeof(grp_str)));
	247	}
	248
04a2eef3	249	static int recv_response(int fd, int hops, struct igmp_mtrace mtracer)
4d9ad5dc MS	250	{
	251	int recvd;
	252	char mtrace_buf[IP_AND_MTRACE_BUF_LEN];
	253	struct ip *ip;
	254	struct igmp_mtrace *mtrace;
	255	int mtrace_len;
	256	int responses;
d7c0a89a	257	unsigned short sum;
813099f0	258	size_t mtrace_off;
813099f0	259	size_t ip_len;
4d9ad5dc MS	260
	261	recvd = recvfrom(fd, mtrace_buf, IP_AND_MTRACE_BUF_LEN, 0, NULL, 0);
	262
	263	if (recvd < 1) {
	264	fprintf(stderr, "recvfrom error: %s\n", strerror(errno));
	265	return -1;
	266	}
	267
	268	if (recvd < (int)sizeof(struct ip)) {
	269	fprintf(stderr, "no ip header\n");
	270	return -1;
	271	}
	272
	273	ip = (struct ip *)mtrace_buf;
	274
	275	if (ip->ip_v != 4) {
	276	fprintf(stderr, "IP not version 4\n");
	277	return -1;
	278	}
	279
	280	sum = ip->ip_sum;
	281	ip->ip_sum = 0;
	282
	283	if (sum != in_cksum(ip, ip->ip_hl * 4))
	284	return -1;
	285
813099f0	286	/* Header overflow check */
	287	mtrace_off = 4 * ip->ip_hl;
	288	if (mtrace_off > MTRACE_BUF_LEN)
18e994a0	289	return -1;
18e994a0	290
813099f0	291	/* Underflow/overflow check */
	292	ip_len = ntohs(ip->ip_len);
	293	if (ip_len < mtrace_off \|\| ip_len < MTRACE_HDR_SIZE
	294	\|\| ip_len > MTRACE_BUF_LEN)
4d9ad5dc MS	295	return -1;
4d9ad5dc MS	296
813099f0	297	mtrace_len = ip_len - mtrace_off;
813099f0	298	mtrace = (struct igmp_mtrace *)(mtrace_buf + mtrace_off);
d94023d8	299
4d9ad5dc MS	300	sum = mtrace->checksum;
	301	mtrace->checksum = 0;
	302	if (sum != in_cksum(mtrace, mtrace_len)) {
	303	fprintf(stderr, "mtrace checksum wrong\n");
	304	return -1;
	305	}
	306
	307	if (mtrace->type != PIM_IGMP_MTRACE_RESPONSE)
	308	return -1;
	309
	310
	311	responses = mtrace_len - sizeof(struct igmp_mtrace);
	312	responses /= sizeof(struct igmp_mtrace_rsp);
	313
04a2eef3 MS	314	if (responses > MTRACE_MAX_HOPS) {
	315	fprintf(stderr, "mtrace too large\n");
	316	return -1;
	317	}
4d9ad5dc MS	318
	319	if (hops)
	320	*hops = responses;
	321
04a2eef3 MS	322	if (mtracer)
04a2eef3 MS	323	memcpy(mtracer, mtrace, mtrace_len);
4d9ad5dc MS	324
	325	return 0;
	326	}
	327
04a2eef3 MS	328	static int wait_for_response(int fd, int hops, struct igmp_mtrace mtrace,
04a2eef3 MS	329	long *ret_msec)
4d9ad5dc MS	330	{
	331	fd_set readfds;
	332	struct timeval timeout;
a2b6e694	333	int ret;
4d9ad5dc MS	334	long msec, rmsec, tmsec;
	335
	336	FD_ZERO(&readfds);
	337	FD_SET(fd, &readfds);
	338
	339	memset(&timeout, 0, sizeof(timeout));
	340
	341	timeout.tv_sec = MTRACE_TIMEOUT;
	342
	343	tmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	344	do {
	345	ret = select(fd + 1, &readfds, NULL, NULL, &timeout);
	346	if (ret <= 0)
	347	return ret;
	348	rmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000;
	349	msec = tmsec - rmsec;
04a2eef3 MS	350	} while (recv_response(fd, hops, mtrace) != 0);
	351
	352	if (ret_msec)
	353	*ret_msec = msec;
4d9ad5dc MS	354
	355	return ret;
	356	}
	357
04a2eef3 MS	358	static bool check_end(struct igmp_mtrace *mtrace, int hops)
	359	{
	360	return mtrace->src_addr.s_addr == mtrace->rsp[hops - 1].prev_hop.s_addr;
	361	}
	362
4d9ad5dc MS	363	int main(int argc, char *const argv[])
	364	{
	365	struct in_addr mc_source;
71e55fb2	366	struct in_addr mc_group;
4d9ad5dc MS	367	struct in_addr iface_addr;
	368	struct in_addr gw_addr;
	369	struct in_addr mtrace_addr;
	370	struct igmp_mtrace mtrace;
04a2eef3	371	struct igmp_mtrace *mtracep;
4d9ad5dc MS	372	int hops = 255;
	373	int rhops;
	374	int maxhops = 255;
	375	int perhop = 3;
	376	int ifindex;
	377	int unicast = 1;
	378	int ttl = 64;
	379	int fd = -1;
	380	int ret = -1;
	381	int c;
04a2eef3	382	long msec;
4d9ad5dc MS	383	int i, j;
4d9ad5dc MS	384	char ifname[IF_NAMESIZE];
04a2eef3	385	char mbuf[MTRACE_BUF_LEN];
71e55fb2	386	bool not_group;
4d9ad5dc MS	387
	388	mtrace_addr.s_addr = inet_addr("224.0.1.32");
	389
	390	uid_t uid = getuid();
	391
	392	if (uid != 0) {
	393	printf("must run as root\n");
	394	exit(EXIT_FAILURE);
	395	}
	396
	397	if (argc <= 0)
	398	progname = "mtracebis";
	399	else
	400	progname = argv[0];
	401
71e55fb2	402	if (argc != 2 && argc != 3) {
4d9ad5dc MS	403	usage();
	404	exit(EXIT_FAILURE);
	405	}
	406
	407	while (1) {
	408	static struct option long_options[] = {
	409	{"help", no_argument, 0, 'h'},
	410	{"version", no_argument, 0, 'v'},
996c9314	411	{0, 0, 0, 0}};
4d9ad5dc MS	412	int option_index = 0;
	413
	414	c = getopt_long(argc, argv, "vh", long_options, &option_index);
	415
	416	if (c == -1)
	417	break;
	418
	419	switch (c) {
	420	case 'h':
	421	usage();
	422	exit(0);
	423	case 'v':
	424	version();
	425	exit(0);
	426	default:
	427	usage();
	428	exit(EXIT_FAILURE);
	429	}
	430	}
	431	if (inet_pton(AF_INET, argv[1], &mc_source) != 1) {
	432	usage();
71e55fb2	433	fprintf(stderr, "%s: %s is not a valid IPv4 address\n", argv[0],
4d9ad5dc MS	434	argv[1]);
	435	exit(EXIT_FAILURE);
	436	}
	437
975a328e	438	mc_group.s_addr = INADDR_ANY;
71e55fb2 MS	439	not_group = false;
	440
	441	if (argc == 3) {
	442	if (inet_pton(AF_INET, argv[2], &mc_group) != 1)
	443	not_group = true;
	444	if (!not_group && !IPV4_CLASS_DE(ntohl(mc_group.s_addr)))
	445	not_group = true;
	446	}
	447
	448	if (not_group) {
	449	usage();
	450	fprintf(stderr, "%s: %s is not a valid IPv4 group address\n",
	451	argv[0], argv[2]);
	452	exit(EXIT_FAILURE);
	453	}
	454
4d9ad5dc MS	455	ifindex = routeget(mc_source, &iface_addr, &gw_addr);
	456	if (ifindex < 0) {
	457	fprintf(stderr, "%s: failed to get route to source %s\n",
	458	argv[0], argv[1]);
	459	exit(EXIT_FAILURE);
	460	}
	461
	462	if (if_indextoname(ifindex, ifname) == NULL) {
	463	fprintf(stderr, "%s: if_indextoname error: %s\n", argv[0],
	464	strerror(errno));
	465	exit(EXIT_FAILURE);
	466	}
	467
	468	/* zero mtrace struct */
	469	memset((char *)&mtrace, 0, sizeof(mtrace));
	470
	471	/* set up query */
	472	mtrace.type = PIM_IGMP_MTRACE_QUERY_REQUEST;
	473	mtrace.hops = hops;
	474	mtrace.checksum = 0;
71e55fb2	475	mtrace.grp_addr = mc_group;
4d9ad5dc MS	476	mtrace.src_addr = mc_source;
	477	mtrace.dst_addr = iface_addr;
	478	mtrace.rsp_addr = unicast ? iface_addr : mtrace_addr;
	479	mtrace.rsp_ttl = ttl;
	480	mtrace.qry_id = 0xffffff & time(NULL);
	481
	482	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
	483
	484	fd = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP);
	485
	486	if (fd < 1) {
	487	fprintf(stderr, "%s: socket error: %s\n", argv[0],
	488	strerror(errno));
	489	exit(EXIT_FAILURE);
	490	}
	491
	492	ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
	493	strlen(ifname));
	494
	495	if (ret < 0) {
	496	fprintf(stderr, "%s: setsockopt error: %s\n", argv[0],
	497	strerror(errno));
	498	ret = EXIT_FAILURE;
	499	goto close_fd;
	500	}
	501
	502	print_query(&mtrace);
	503	if (send_query(fd, gw_addr, &mtrace) < 0) {
	504	fprintf(stderr, "%s: sendto error: %s\n", argv[0],
	505	strerror(errno));
	506	ret = EXIT_FAILURE;
	507	goto close_fd;
	508	}
	509	printf("Querying full reverse path...\n");
04a2eef3 MS	510	mtracep = (struct igmp_mtrace *)mbuf;
04a2eef3 MS	511	ret = wait_for_response(fd, &rhops, mtracep, &msec);
4d9ad5dc	512	if (ret > 0) {
04a2eef3	513	print_responses(mtracep, rhops, msec);
4d9ad5dc MS	514	ret = 0;
	515	goto close_fd;
	516	}
	517	if (ret < 0) {
	518	fprintf(stderr, "%s: select error: %s\n", argv[0],
	519	strerror(errno));
	520	ret = EXIT_FAILURE;
	521	goto close_fd;
	522	}
	523	printf(" * ");
	524	printf("switching to hop-by-hop:\n");
04a2eef3	525	print_dest(&mtrace);
4d9ad5dc	526	for (i = 1; i < maxhops; i++) {
04a2eef3	527	print_line_no(i);
4d9ad5dc MS	528	mtrace.hops = i;
	529	for (j = 0; j < perhop; j++) {
	530	mtrace.qry_id++;
	531	mtrace.checksum = 0;
	532	mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace));
	533	if (send_query(fd, gw_addr, &mtrace) < 0) {
	534	fprintf(stderr, "%s: sendto error: %s\n",
	535	argv[0], strerror(errno));
	536	ret = EXIT_FAILURE;
	537	goto close_fd;
	538	}
04a2eef3	539	ret = wait_for_response(fd, &rhops, mtracep, &msec);
4d9ad5dc	540	if (ret > 0) {
04a2eef3 MS	541	if (check_end(mtracep, rhops)) {
	542	print_rsp(&mtracep->rsp[rhops - 1]);
	543	print_summary(mtracep, rhops, msec);
	544	ret = 0;
	545	goto close_fd;
	546	}
4d9ad5dc	547	if (i > rhops) {
04a2eef3	548	printf(" * ...giving up.\n");
4d9ad5dc MS	549	ret = 0;
	550	goto close_fd;
	551	}
04a2eef3	552	print_rsp(&mtracep->rsp[rhops - 1]);
4d9ad5dc MS	553	break;
	554	}
	555	printf(" *");
	556	}
	557	if (ret <= 0)
	558	printf("\n");
	559	}
	560	ret = 0;
	561	close_fd:
	562	close(fd);
	563	exit(ret);
	564	}
	565
	566	#else /* __linux__ */
	567
	568	#include <stdio.h>
	569	#include <stdlib.h>
	570
	571	int main(int argc, char *argv[])
	572	{
	573	printf("%s implemented only for GNU/Linux\n", argv[0]);
	574	exit(0);
	575	}
	576
	577	#endif /* __linux__ */