/*-
 * Copyright (c) 2007 Bruce M. Simpson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Regression test utility for RFC 3678 Advanced Multicast API in FreeBSD.
 *
 * TODO: Test the SSM paths.
 * TODO: Support INET6. The code has been written to facilitate this later.
 * TODO: Merge multicast socket option tests from ipsockopt.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <getopt.h>
#include <libgen.h>
#include <pwd.h>
#include <setjmp.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <time.h>
#include <unistd.h>

#ifndef __SOCKUNION_DECLARED
union sockunion {
        struct sockaddr_storage ss;
        struct sockaddr         sa;
        struct sockaddr_dl      sdl;
        struct sockaddr_in      sin;
#ifdef INET6
        struct sockaddr_in6     sin6;
#endif
};
typedef union sockunion sockunion_t;
#define __SOCKUNION_DECLARED
#endif /* __SOCKUNION_DECLARED */

#define ADDRBUF_LEN             16
#define DEFAULT_GROUP_STR       "238.1.1.0"
#define DEFAULT_IFNAME          "lo0"
#define DEFAULT_IFADDR_STR      "127.0.0.1"
#define DEFAULT_PORT            6698
#define DEFAULT_TIMEOUT         0               /* don't wait for traffic */
#define RXBUFSIZE               2048

static sockunion_t       basegroup;
static const char       *basegroup_str = NULL;
static int               dobindaddr = 0;
static int               dodebug = 1;
static int               doipv4 = 0;
static int               domiscopts = 0;
static int               dorandom = 0;
static int               doreuseport = 0;
static int               dossm = 0;
static int               dossf = 0;
static int               doverbose = 0;
static sockunion_t       ifaddr;
static const char       *ifaddr_str = NULL;
static uint32_t          ifindex = 0;
static const char       *ifname = NULL;
struct in_addr          *ipv4_sources = NULL;
static jmp_buf           jmpbuf;
static size_t            nmcastgroups = IP_MAX_MEMBERSHIPS;
static size_t            nmcastsources = 0;
static uint16_t          portno = DEFAULT_PORT;
static char             *progname = NULL;
struct sockaddr_storage *ss_sources = NULL;
static uint32_t          timeout = 0;

static int      do_asm_ipv4(void);
static int      do_asm_pim(void);
#ifdef notyet
static int      do_misc_opts(void);
#endif
static int      do_ssf_ipv4(void);
static int      do_ssf_pim(void);
static int      do_ssm_ipv4(void);
static int      do_ssm_pim(void);
static int      open_and_bind_socket(sockunion_t *);
static int      recv_loop_with_match(int, sockunion_t *, sockunion_t *);
static void     signal_handler(int);
static void     usage(void);

/*
 * Test the IPv4 set/getipv4sourcefilter() libc API functions.
 * Build a single socket.
 * Join a source group.
 * Repeatedly change the source filters via setipv4sourcefilter.
 * Read it back with getipv4sourcefilter up to IP_MAX_SOURCES
 * and check for inconsistency.
 */
static int
do_ssf_ipv4(void)
{

        fprintf(stderr, "not yet implemented\n");
        return (0);
}

/*
 * Test the protocol-independent set/getsourcefilter() functions.
 */
static int
do_ssf_pim(void)
{

        fprintf(stderr, "not yet implemented\n");
        return (0);
}

/*
 * Test the IPv4 ASM API.
 * Repeatedly join, block sources, unblock and leave groups.
 */
static int
do_asm_ipv4(void)
{
        int                      error;
        char                     gaddrbuf[ADDRBUF_LEN];
        int                      i;
        sockunion_t              laddr;
        struct ip_mreq           mreq;
        struct ip_mreq_source    mreqs;
        in_addr_t                ngroupbase;
        char                     saddrbuf[ADDRBUF_LEN];
        int                      sock;
        sockunion_t              tmpgroup;
        sockunion_t              tmpsource;

        memset(&mreq, 0, sizeof(struct ip_mreq));
        memset(&mreqs, 0, sizeof(struct ip_mreq_source));
        memset(&laddr, 0, sizeof(sockunion_t));

        if (dobindaddr) {
                laddr = ifaddr;
        } else {
                laddr.sin.sin_family = AF_INET;
                laddr.sin.sin_len = sizeof(struct sockaddr_in);
                laddr.sin.sin_addr.s_addr = INADDR_ANY;
        }
        laddr.sin.sin_port = htons(portno);

        tmpgroup = basegroup;
        ngroupbase = ntohl(basegroup.sin.sin_addr.s_addr) + 1;  /* XXX */
        tmpgroup.sin.sin_addr.s_addr = htonl(ngroupbase);

        sock = open_and_bind_socket(&laddr);
        if (sock == -1)
                return (EX_OSERR);

        for (i = 0; i < (signed)nmcastgroups; i++) {
                mreq.imr_multiaddr.s_addr = htonl((ngroupbase + i));
                mreq.imr_interface = ifaddr.sin.sin_addr;
                if (doverbose) {
                        inet_ntop(AF_INET, &mreq.imr_multiaddr, gaddrbuf,
                            sizeof(gaddrbuf));
                        fprintf(stderr, "IP_ADD_MEMBERSHIP %s %s\n",
                            gaddrbuf, inet_ntoa(mreq.imr_interface));
                }
                error = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                    &mreq, sizeof(struct ip_mreq));
                if (error < 0) {
                        warn("setsockopt IP_ADD_MEMBERSHIP");
                        close(sock);
                        return (EX_OSERR);
                }
        }

        /*
         * If no test sources auto-generated or specified on command line,
         * skip source filter portion of ASM test.
        */
        if (nmcastsources == 0)
                goto skipsources;

        /*
         * Begin blocking sources on the first group chosen.
         */
        for (i = 0; i < (signed)nmcastsources; i++) {
                mreqs.imr_multiaddr = tmpgroup.sin.sin_addr;
                mreqs.imr_interface = ifaddr.sin.sin_addr;
                mreqs.imr_sourceaddr = ipv4_sources[i];
                if (doverbose) {
                        inet_ntop(AF_INET, &mreqs.imr_multiaddr, gaddrbuf,
                            sizeof(gaddrbuf));
                        inet_ntop(AF_INET, &mreqs.imr_sourceaddr, saddrbuf,
                            sizeof(saddrbuf));
                        fprintf(stderr, "IP_BLOCK_SOURCE %s %s %s\n",
                            gaddrbuf, inet_ntoa(mreqs.imr_interface),
                            saddrbuf);
                }
                error = setsockopt(sock, IPPROTO_IP, IP_BLOCK_SOURCE, &mreqs,
                    sizeof(struct ip_mreq_source));
                if (error < 0) {
                        warn("setsockopt IP_BLOCK_SOURCE");
                        close(sock);
                        return (EX_OSERR);
                }
        }

        /*
         * Choose the first group and source for a match.
         * Enter the I/O loop.
         */
        memset(&tmpsource, 0, sizeof(sockunion_t));
        tmpsource.sin.sin_family = AF_INET;
        tmpsource.sin.sin_len = sizeof(struct sockaddr_in);
        tmpsource.sin.sin_addr = ipv4_sources[0];

        error = recv_loop_with_match(sock, &tmpgroup, &tmpsource);

        /*
         * Unblock sources.
         */
        for (i = nmcastsources-1; i >= 0; i--) {
                mreqs.imr_multiaddr = tmpgroup.sin.sin_addr;
                mreqs.imr_interface = ifaddr.sin.sin_addr;
                mreqs.imr_sourceaddr = ipv4_sources[i];
                if (doverbose) {
                        inet_ntop(AF_INET, &mreqs.imr_multiaddr, gaddrbuf,
                            sizeof(gaddrbuf));
                        inet_ntop(AF_INET, &mreqs.imr_sourceaddr, saddrbuf,
                            sizeof(saddrbuf));
                        fprintf(stderr, "IP_UNBLOCK_SOURCE %s %s %s\n",
                            gaddrbuf, inet_ntoa(mreqs.imr_interface),
                            saddrbuf);
                }
                error = setsockopt(sock, IPPROTO_IP, IP_UNBLOCK_SOURCE, &mreqs,
                    sizeof(struct ip_mreq_source));
                if (error < 0) {
                        warn("setsockopt IP_UNBLOCK_SOURCE");
                        close(sock);
                        return (EX_OSERR);
                }
        }

skipsources:
        /*
         * Leave groups.
         */
        for (i = nmcastgroups-1; i >= 0; i--) {
                mreq.imr_multiaddr.s_addr = htonl((ngroupbase + i));
                mreq.imr_interface = ifaddr.sin.sin_addr;
                if (doverbose) {
                        inet_ntop(AF_INET, &mreq.imr_multiaddr, gaddrbuf,
                            sizeof(gaddrbuf));
                        fprintf(stderr, "IP_DROP_MEMBERSHIP %s %s\n",
                            gaddrbuf, inet_ntoa(mreq.imr_interface));
                }
                error = setsockopt(sock, IPPROTO_IP, IP_DROP_MEMBERSHIP,
                    &mreq, sizeof(struct ip_mreq));
                if (error < 0) {
                        warn("setsockopt IP_DROP_MEMBERSHIP");
                        close(sock);
                        return (EX_OSERR);
                }
        }

        return (0);
}

static int
do_asm_pim(void)
{

        fprintf(stderr, "not yet implemented\n");
        return (0);
}

#ifdef notyet
/*
 * Test misceallaneous IPv4 options.
 */
static int
do_misc_opts(void)
{
        int sock;

        sock = open_and_bind_socket(NULL);
        if (sock == -1)
                return (EX_OSERR);
        test_ip_uchar(sock, socktypename, IP_MULTICAST_TTL,
            "IP_MULTICAST_TTL", 1);
        close(sock);

        sock = open_and_bind_socket(NULL);
        if (sock == -1)
                return (EX_OSERR);
        test_ip_boolean(sock, socktypename, IP_MULTICAST_LOOP,
            "IP_MULTICAST_LOOP", 1, BOOLEAN_ANYONE);
        close(sock);

        return (0);
}
#endif

/*
 * Test the IPv4 SSM API.
 */
static int
do_ssm_ipv4(void)
{

        fprintf(stderr, "not yet implemented\n");
        return (0);
}

/*
 * Test the protocol-independent SSM API with IPv4 addresses.
 */
static int
do_ssm_pim(void)
{

        fprintf(stderr, "not yet implemented\n");
        return (0);
}

int
main(int argc, char *argv[])
{
        struct addrinfo          aih;
        struct addrinfo         *aip;
        int                      ch;
        int                      error;
        int                      exitval;
        size_t                   i;
        struct in_addr          *pina;
        struct sockaddr_storage *pbss;

        ifname = DEFAULT_IFNAME;
        ifaddr_str = DEFAULT_IFADDR_STR;
        basegroup_str = DEFAULT_GROUP_STR;
        ifname = DEFAULT_IFNAME;
        portno = DEFAULT_PORT;
        basegroup.ss.ss_family = AF_UNSPEC;
        ifaddr.ss.ss_family = AF_UNSPEC;

        progname = basename(argv[0]);
        while ((ch = getopt(argc, argv, "4bg:i:I:mM:p:rsS:tT:v")) != -1) {
                switch (ch) {
                case '4':
                        doipv4 = 1;
                        break;
                case 'b':
                        dobindaddr = 1;
                        break;
                case 'g':
                        basegroup_str = optarg;
                        break;
                case 'i':
                        ifname = optarg;
                        break;
                case 'I':
                        ifaddr_str = optarg;
                        break;
                case 'm':
                        usage();        /* notyet */
                        /*NOTREACHED*/
                        domiscopts = 1;
                        break;
                case 'M':
                        nmcastgroups = atoi(optarg);
                        break;
                case 'p':
                        portno = atoi(optarg);
                        break;
                case 'r':
                        doreuseport = 1;
                        break;
                case 'S':
                        nmcastsources = atoi(optarg);
                        break;
                case 's':
                        dossm = 1;
                        break;
                case 't':
                        dossf = 1;
                        break;
                case 'T':
                        timeout = atoi(optarg);
                        break;
                case 'v':
                        doverbose = 1;
                        break;
                default:
                        usage();
                        break;
                        /*NOTREACHED*/
                }
        }
        argc -= optind;
        argv += optind;

        memset(&aih, 0, sizeof(struct addrinfo));
        aih.ai_flags = AI_NUMERICHOST | AI_PASSIVE;
        aih.ai_family = PF_INET;
        aih.ai_socktype = SOCK_DGRAM;
        aih.ai_protocol = IPPROTO_UDP;

        /*
         * Fill out base group.
         */
        aip = NULL;
        error = getaddrinfo(basegroup_str, NULL, &aih, &aip);
        if (error != 0) {
                fprintf(stderr, "%s: getaddrinfo: %s\n", progname,
                    gai_strerror(error));
                exit(EX_USAGE);
        }
        memcpy(&basegroup, aip->ai_addr, aip->ai_addrlen);
        if (dodebug) {
                fprintf(stderr, "debug: gai thinks %s is %s\n",
                    basegroup_str, inet_ntoa(basegroup.sin.sin_addr));
        }
        freeaddrinfo(aip);

        assert(basegroup.ss.ss_family == AF_INET);

        /*
         * If user specified interface as an address, and protocol
         * specific APIs were selected, parse it.
         * Otherwise, parse interface index from name if protocol
         * independent APIs were selected (the default).
         */
        if (doipv4) {
                if (ifaddr_str == NULL) {
                        warnx("required argument missing: ifaddr");
                        usage();
                        /* NOTREACHED */
                }
                aip = NULL;
                error = getaddrinfo(ifaddr_str, NULL, &aih, &aip);
                if (error != 0) {
                        fprintf(stderr, "%s: getaddrinfo: %s\n", progname,
                            gai_strerror(error));
                        exit(EX_USAGE);
                }
                memcpy(&ifaddr, aip->ai_addr, aip->ai_addrlen);
                if (dodebug) {
                        fprintf(stderr, "debug: gai thinks %s is %s\n",
                            ifaddr_str, inet_ntoa(ifaddr.sin.sin_addr));
                }
                freeaddrinfo(aip);
        }

        if (!doipv4) {
                if (ifname == NULL) {
                        warnx("required argument missing: ifname");
                        usage();
                        /* NOTREACHED */
                }
                ifindex = if_nametoindex(ifname);
                if (ifindex == 0)
                        err(EX_USAGE, "if_nametoindex");
        }

        /*
         * Introduce randomness into group base if specified.
         */
        if (dorandom) {
                in_addr_t ngroupbase;

                srandomdev();
                ngroupbase = ntohl(basegroup.sin.sin_addr.s_addr);
                ngroupbase |= ((random() % ((1 << 11) - 1)) << 16);
                basegroup.sin.sin_addr.s_addr = htonl(ngroupbase);
        }

        if (argc > 0) {
                nmcastsources = argc;
                if (doipv4) {
                        ipv4_sources = calloc(nmcastsources,
                            sizeof(struct in_addr));
                        if (ipv4_sources == NULL) {
                                exitval = EX_OSERR;
                                goto out;
                        }
                } else {
                        ss_sources = calloc(nmcastsources,
                            sizeof(struct sockaddr_storage));
                        if (ss_sources == NULL) {
                                exitval = EX_OSERR;
                                goto out;
                        }
                }
        }

        /*
         * Parse source list, if any were specified on the command line.
         */
        assert(aih.ai_family == PF_INET);
        pbss = ss_sources;
        pina = ipv4_sources;
        for (i = 0; i < (size_t)argc; i++) {
                aip = NULL;
                error = getaddrinfo(argv[i], NULL, &aih, &aip);
                if (error != 0) {
                        fprintf(stderr, "getaddrinfo: %s\n",
                            gai_strerror(error));
                        exitval = EX_USAGE;
                        goto out;
                }
                if (doipv4) {
                        struct sockaddr_in *sin =
                            (struct sockaddr_in *)aip->ai_addr;
                        *pina++ = sin->sin_addr;
                } else {
                        memcpy(pbss++, aip->ai_addr, aip->ai_addrlen);
                }
                freeaddrinfo(aip);
        }

        /*
         * Perform the regression tests which the user requested.
         */
#ifdef notyet
        if (domiscopts) {
                exitval = do_misc_opts();
                if (exitval)
                        goto out;
        }
#endif
        if (doipv4) {
                /* IPv4 protocol specific API tests */
                if (dossm) {
                        /* Source-specific multicast */
                        exitval = do_ssm_ipv4();
                        if (exitval)
                                goto out;
                        if (dossf) {
                                /* Do setipvsourcefilter() too */
                                exitval = do_ssf_ipv4();
                        }
                } else {
                        /* Any-source multicast */
                        exitval = do_asm_ipv4();
                }
        } else {
                /* Protocol independent API tests */
                if (dossm) {
                        /* Source-specific multicast */
                        exitval = do_ssm_pim();
                        if (exitval)
                                goto out;
                        if (dossf) {
                                /* Do setsourcefilter() too */
                                exitval = do_ssf_pim();
                        }
                } else {
                        /* Any-source multicast */
                        exitval = do_asm_pim();
                }
        }

out:
        if (ipv4_sources != NULL)
                free(ipv4_sources);

        if (ss_sources != NULL)
                free(ss_sources);

        exit(exitval);
}

static int
open_and_bind_socket(sockunion_t *bsu)
{
        int      error, optval, sock;

        sock = -1;

        sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
        if (sock == -1) {
                warn("socket");
                return (-1);
        }

        if (doreuseport) {
                optval = 1;
                if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &optval,
                    sizeof(optval)) < 0) {
                        warn("setsockopt SO_REUSEPORT");
                        close(sock);
                        return (-1);
                }
        }

        if (bsu != NULL) {
                error = bind(sock, &bsu->sa, bsu->sa.sa_len);
                if (error == -1) {
                        warn("bind");
                        close(sock);
                        return (-1);
                }
        }

        return (sock);
}

/*
 * Protocol-agnostic multicast I/O loop.
 *
 * Wait for 'timeout' seconds looking for traffic on group, so that manual
 * or automated regression tests (possibly running on another host) have an
 * opportunity to transmit within the group to test source filters.
 *
 * If the filter failed, this loop will report if we received traffic
 * from the source we elected to monitor.
 */
static int
recv_loop_with_match(int sock, sockunion_t *group, sockunion_t *source)
{
        int              error;
        sockunion_t      from;
        char             groupname[NI_MAXHOST];
        ssize_t          len;
        size_t           npackets;
        int              jmpretval;
        char             rxbuf[RXBUFSIZE];
        char             sourcename[NI_MAXHOST];

        assert(source->sa.sa_family == AF_INET);

        /*
         * Return immediately if we don't need to wait for traffic.
         */
        if (timeout == 0)
                return (0);

        error = getnameinfo(&group->sa, group->sa.sa_len, groupname,
            NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
        if (error) {
                fprintf(stderr, "getnameinfo: %s\n", gai_strerror(error));
                return (error);
        }

        error = getnameinfo(&source->sa, source->sa.sa_len, sourcename,
            NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
        if (error) {
                fprintf(stderr, "getnameinfo: %s\n", gai_strerror(error));
                return (error);
        }

        fprintf(stdout,
            "Waiting %d seconds for inbound traffic on group %s\n"
            "Expecting no traffic from blocked source: %s\n",
            (int)timeout, groupname, sourcename);

        signal(SIGINT, signal_handler);
        signal(SIGALRM, signal_handler);

        error = 0;
        npackets = 0;
        alarm(timeout);
        while (0 == (jmpretval = setjmp(jmpbuf))) {
                len = recvfrom(sock, rxbuf, RXBUFSIZE, 0, &from.sa,
                    (socklen_t *)&from.sa.sa_len);
                if (dodebug) {
                        fprintf(stderr, "debug: packet received from %s\n",
                            inet_ntoa(from.sin.sin_addr));
                }
                if (source &&
                    source->sin.sin_addr.s_addr == from.sin.sin_addr.s_addr)
                        break;
                npackets++;
        }

        if (doverbose) {
                fprintf(stderr, "Number of datagrams received from "
                    "non-blocked sources: %d\n", (int)npackets);
        }

        switch (jmpretval) {
        case SIGALRM:   /* ok */
                break;
        case SIGINT:    /* go bye bye */
                fprintf(stderr, "interrupted\n");
                error = 20;
                break;
        case 0:         /* Broke out of loop; saw a bad source. */
                fprintf(stderr, "FAIL: got packet from blocked source\n");
                error = EX_IOERR;
                break;
        default:
                warnx("recvfrom");
                error = EX_OSERR;
                break;
        }

        signal(SIGINT, SIG_DFL);
        signal(SIGALRM, SIG_DFL);

        return (error);
}

static void
signal_handler(int signo)
{

        longjmp(jmpbuf, signo);
}

static void
usage(void)
{

        fprintf(stderr, "\nIP multicast regression test utility\n");
        fprintf(stderr,
"usage: %s [-4] [-b] [-g groupaddr] [-i ifname] [-I ifaddr] [-m]\n"
"       [-M ngroups] [-p portno] [-r] [-R] [-s] [-S nsources] [-t] [-T timeout]\n"
"       [-v] [blockaddr ...]\n\n", progname);
        fprintf(stderr, "-4: Use IPv4 API "
                        "(default: Use protocol-independent API)\n");
        fprintf(stderr, "-b: bind listening socket to ifaddr "
            "(default: INADDR_ANY)\n");
        fprintf(stderr, "-g: Base IPv4 multicast group to join (default: %s)\n",
            DEFAULT_GROUP_STR);
        fprintf(stderr, "-i: interface for multicast joins (default: %s)\n",
            DEFAULT_IFNAME);
        fprintf(stderr, "-I: IPv4 address to join groups on, if using IPv4 "
            "API\n    (default: %s)\n", DEFAULT_IFADDR_STR);
#ifdef notyet
        fprintf(stderr, "-m: Test misc IPv4 multicast socket options "
            "(default: off)\n");
#endif
        fprintf(stderr, "-M: Number of multicast groups to join "
            "(default: %d)\n", (int)nmcastgroups);
        fprintf(stderr, "-p: Set local and remote port (default: %d)\n",
            DEFAULT_PORT);
        fprintf(stderr, "-r: Set SO_REUSEPORT on (default: off)\n");
        fprintf(stderr, "-R: Randomize groups/sources (default: off)\n");
        fprintf(stderr, "-s: Test source-specific API "
            "(default: test any-source API)\n");
        fprintf(stderr, "-S: Number of multicast sources to generate if\n"
            "    none specified on command line (default: %d)\n",
            (int)nmcastsources);
        fprintf(stderr, "-t: Test get/setNsourcefilter() (default: off)\n");
        fprintf(stderr, "-T: Timeout to wait for blocked traffic on first "
            "group (default: %d)\n", DEFAULT_TIMEOUT);
        fprintf(stderr, "-v: Be verbose (default: off)\n");
        fprintf(stderr, "\nRemaining arguments are treated as a list of IPv4 "
            "sources to filter.\n\n");

        exit(EX_USAGE);
}