/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2007-2009 Bruce Simpson.
 * Copyright (c) 2000 Wilbert De Graaf.
 * 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
 * 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.
 */

/*
 * Diagnostic and test utility for multicast sockets.
 * XXX: This file currently assumes INET support in the base system.
 * TODO: Support embedded KAME Scope ID in IPv6 group addresses.
 * TODO: Use IPv4 link-local address when source address selection
 * is implemented; use MCAST_JOIN_SOURCE for IPv4.
 */

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

#include <net/if.h>
#include <net/if_dl.h>
#include <net/ethernet.h>
#ifdef INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#endif
#ifdef INET6
#include <netinet/in.h>
#include <netinet/ip6.h>
#endif

#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <err.h>
#include <unistd.h>

#include <arpa/inet.h>
#include <netdb.h>
#include <ifaddrs.h>

union sockunion {
        struct sockaddr_storage ss;
        struct sockaddr         sa;
        struct sockaddr_dl      sdl;
#ifdef INET
        struct sockaddr_in      sin;
#endif
#ifdef INET6
        struct sockaddr_in6     sin6;
#endif
};
typedef union sockunion sockunion_t;

union mrequnion {
#ifdef INET
        struct ip_mreq           mr;
        struct ip_mreq_source    mrs;
#endif
#ifdef INET6
        struct ipv6_mreq         mr6;
        struct group_source_req  gr;
#endif
};
typedef union mrequnion mrequnion_t;

#define MAX_ADDRS       20
#define STR_SIZE        20
#define LINE_LENGTH     80

#ifdef INET
static int      __ifindex_to_primary_ip(const uint32_t, struct in_addr *);
#endif
static uint32_t parse_cmd_args(sockunion_t *, sockunion_t *,
                    const char *, const char *, const char *);
static void     process_file(char *, int, int);
static void     process_cmd(char*, int, int, FILE *);
static int      su_cmp(const void *, const void *);
static void     usage(void);

/*
 * Ordering predicate for qsort().
 */
static int
su_cmp(const void *a, const void *b)
{
        const sockunion_t       *sua = (const sockunion_t *)a;
        const sockunion_t       *sub = (const sockunion_t *)b;

        assert(sua->sa.sa_family == sub->sa.sa_family);

        switch (sua->sa.sa_family) {
#ifdef INET
        case AF_INET:
                return ((int)(sua->sin.sin_addr.s_addr -
                    sub->sin.sin_addr.s_addr));
                break;
#endif
#ifdef INET6
        case AF_INET6:
                return (memcmp(&sua->sin6.sin6_addr, &sub->sin6.sin6_addr,
                    sizeof(struct in6_addr)));
                break;
#endif
        default:
                break;
        }

        assert(sua->sa.sa_len == sub->sa.sa_len);
        return (memcmp(sua, sub, sua->sa.sa_len));
}

#ifdef INET
/*
 * Internal: Map an interface index to primary IPv4 address.
 * This is somewhat inefficient. This is a useful enough operation
 * that it probably belongs in the C library.
 * Return zero if found, -1 on error, 1 on not found.
 */
static int
__ifindex_to_primary_ip(const uint32_t ifindex, struct in_addr *pina)
{
        char             ifname[IFNAMSIZ];
        struct ifaddrs  *ifa;
        struct ifaddrs  *ifaddrs;
        sockunion_t     *psu;
        int              retval;

        assert(ifindex != 0);

        retval = -1;
        if (if_indextoname(ifindex, ifname) == NULL)
                return (retval);
        if (getifaddrs(&ifaddrs) < 0)
                return (retval);

        /*
         * Find the ifaddr entry corresponding to the interface name,
         * and return the first matching IPv4 address.
         */
        retval = 1;
        for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
                if (strcmp(ifa->ifa_name, ifname) != 0)
                        continue;
                psu = (sockunion_t *)ifa->ifa_addr;
                if (psu && psu->sa.sa_family == AF_INET) {
                        retval = 0;
                        memcpy(pina, &psu->sin.sin_addr,
                            sizeof(struct in_addr));
                        break;
                }
        }

        if (retval != 0)
                errno = EADDRNOTAVAIL;  /* XXX */

        freeifaddrs(ifaddrs);
        return (retval);
}
#endif /* INET */

int
main(int argc, char **argv)
{
        char     line[LINE_LENGTH];
        char    *p;
        int      i, s, s6;

        s = -1;
        s6 = -1;
#ifdef INET
        s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
        if (s == -1 && errno != EAFNOSUPPORT)
                err(1, "can't open IPv4 socket");
#endif
#ifdef INET6
        s6 = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
        if (s6 == -1 && errno != EAFNOSUPPORT)
                err(1, "can't open IPv6 socket");
#endif
        if (s == -1 && s6 == -1)
                errc(1, EPROTONOSUPPORT, "can't open socket");

        if (argc < 2) {
                if (isatty(STDIN_FILENO)) {
                        printf("multicast membership test program; "
                            "enter ? for list of commands\n");
                }
                do {
                        if (fgets(line, sizeof(line), stdin) != NULL) {
                                if (line[0] != 'f')
                                        process_cmd(line, s, s6, stdin);
                                else {
                                        /* Get the filename */
                                        for (i = 1; isblank(line[i]); i++);
                                        if ((p = (char*)strchr(line, '\n'))
                                            != NULL)
                                                *p = '\0';
                                        process_file(&line[i], s, s6);
                                }
                        }
                } while (!feof(stdin));
        } else {
                for (i = 1; i < argc; i++) {
                        process_file(argv[i], s, s6);
                }
        }

        if (s != -1)
                close(s);
        if (s6 != -1)
                close(s6);

        exit (0);
}

static void
process_file(char *fname, int s, int s6)
{
        char line[80];
        FILE *fp;
        char *lineptr;

        fp = fopen(fname, "r");
        if (fp == NULL) {
                warn("fopen");
                return;
        }

        /* Skip comments and empty lines. */
        while (fgets(line, sizeof(line), fp) != NULL) {
                lineptr = line;
                while (isblank(*lineptr))
                        lineptr++;
                if (*lineptr != '#' && *lineptr != '\n')
                        process_cmd(lineptr, s, s6, fp);
        }

        fclose(fp);
}

/*
 * Parse join/leave/allow/block arguments, given:
 *  str1: group (as AF_INET or AF_INET6 printable)
 *  str2: ifname
 *  str3: optional source address (may be NULL).
 *   This argument must have the same parsed address family as str1.
 * Return the ifindex of ifname, or 0 if any parse element failed.
 */
static uint32_t
parse_cmd_args(sockunion_t *psu, sockunion_t *psu2,
    const char *str1, const char *str2, const char *str3)
{
        struct addrinfo          hints;
        struct addrinfo         *res;
        uint32_t                 ifindex;
        int                      af, error;

        assert(psu != NULL);
        assert(str1 != NULL);
        assert(str2 != NULL);

        af = AF_UNSPEC;

        ifindex = if_nametoindex(str2);
        if (ifindex == 0)
                return (0);

        memset(&hints, 0, sizeof(struct addrinfo));
        hints.ai_flags = AI_NUMERICHOST;
        hints.ai_family = PF_UNSPEC;
        hints.ai_socktype = SOCK_DGRAM;

        memset(psu, 0, sizeof(sockunion_t));
        psu->sa.sa_family = AF_UNSPEC;

        error = getaddrinfo(str1, "0", &hints, &res);
        if (error) {
                warnx("getaddrinfo: %s", gai_strerror(error));
                return (0);
        }
        assert(res != NULL);
        af = res->ai_family;
        memcpy(psu, res->ai_addr, res->ai_addrlen);
        freeaddrinfo(res);

        /* sscanf() may pass the empty string. */
        if (psu2 != NULL && str3 != NULL && *str3 != '\0') {
                memset(psu2, 0, sizeof(sockunion_t));
                psu2->sa.sa_family = AF_UNSPEC;

                /* look for following address family; str3 is *optional*. */
                hints.ai_family = af;
                error = getaddrinfo(str3, "0", &hints, &res);
                if (error) {
                        warnx("getaddrinfo: %s", gai_strerror(error));
                        ifindex = 0;
                } else {
                        if (af != res->ai_family) {
                                errno = EINVAL; /* XXX */
                                ifindex = 0;
                        }
                        memcpy(psu2, res->ai_addr, res->ai_addrlen);
                        freeaddrinfo(res);
                }
        }

        return (ifindex);
}

static __inline int
af2sock(const int af, int s, int s6)
{

#ifdef INET
        if (af == AF_INET)
                return (s);
#endif
#ifdef INET6
        if (af == AF_INET6)
                return (s6);
#endif
        return (-1);
}

static __inline int
af2socklen(const int af)
{

#ifdef INET
        if (af == AF_INET)
                return (sizeof(struct sockaddr_in));
#endif
#ifdef INET6
        if (af == AF_INET6)
                return (sizeof(struct sockaddr_in6));
#endif
        return (-1);
}

static void
process_cmd(char *cmd, int s, int s6, FILE *fp __unused)
{
        char                     str1[STR_SIZE];
        char                     str2[STR_SIZE];
        char                     str3[STR_SIZE];
        mrequnion_t              mr;
        sockunion_t              su, su2;
        struct ifreq             ifr;
        char                    *line;
        char                    *toptname;
        void                    *optval;
        uint32_t                 fmode, ifindex;
        socklen_t                optlen;
        size_t                   j;
        int                      af, error, f, flags, i, level, n, optname;

        af = AF_UNSPEC;
        su.sa.sa_family = AF_UNSPEC;
        su2.sa.sa_family = AF_UNSPEC;

        line = cmd;
        while (isblank(*++line))
                ;       /* Skip whitespace. */

        n = 0;
        switch (*cmd) {
        case '?':
                usage();
                break;

        case 'q':
                close(s);
                exit(0);

        case 's':
                if ((sscanf(line, "%d", &n) != 1) || (n < 1)) {
                        printf("-1\n");
                        break;
                }
                sleep(n);
                printf("ok\n");
                break;

        case 'j':
        case 'l':
                str3[0] = '\0';
                toptname = "";
                sscanf(line, "%s %s %s", str1, str2, str3);
                ifindex = parse_cmd_args(&su, &su2, str1, str2, str3);
                if (ifindex == 0) {
                        printf("-1\n");
                        break;
                }
                af = su.sa.sa_family;
#ifdef INET
                if (af == AF_INET) {
                        struct in_addr ina;

                        error = __ifindex_to_primary_ip(ifindex, &ina);
                        if (error != 0) {
                                warn("primary_ip_lookup %s", str2);
                                printf("-1\n");
                                break;
                        }
                        level = IPPROTO_IP;

                        if (su2.sa.sa_family != AF_UNSPEC) {
                                mr.mrs.imr_multiaddr = su.sin.sin_addr;
                                mr.mrs.imr_sourceaddr = su2.sin.sin_addr;
                                mr.mrs.imr_interface = ina;
                                optname = (*cmd == 'j') ?
                                    IP_ADD_SOURCE_MEMBERSHIP :
                                    IP_DROP_SOURCE_MEMBERSHIP;
                                toptname = (*cmd == 'j') ?
                                    "IP_ADD_SOURCE_MEMBERSHIP" :
                                    "IP_DROP_SOURCE_MEMBERSHIP";
                                optval = (void *)&mr.mrs;
                                optlen = sizeof(mr.mrs);
                        } else {
                                mr.mr.imr_multiaddr = su.sin.sin_addr;
                                mr.mr.imr_interface = ina;
                                optname = (*cmd == 'j') ?
                                    IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP;
                                toptname = (*cmd == 'j') ?
                                    "IP_ADD_MEMBERSHIP" : "IP_DROP_MEMBERSHIP";
                                optval = (void *)&mr.mr;
                                optlen = sizeof(mr.mr);
                        }
                        if (s < 0) {
                                warnc(EPROTONOSUPPORT, "setsockopt %s",
                                    toptname);
                        } else if (setsockopt(s, level, optname, optval,
                            optlen) == 0) {
                                printf("ok\n");
                                break;
                        } else {
                                warn("setsockopt %s", toptname);
                        }
                }
#ifdef INET6
                else
#endif /* INET with INET6 */
#endif /* INET */
#ifdef INET6
                if (af == AF_INET6) {
                        level = IPPROTO_IPV6;
                        if (su2.sa.sa_family != AF_UNSPEC) {
                                mr.gr.gsr_interface = ifindex;
                                mr.gr.gsr_group = su.ss;
                                mr.gr.gsr_source = su2.ss;
                                optname = (*cmd == 'j') ?
                                    MCAST_JOIN_SOURCE_GROUP:
                                    MCAST_LEAVE_SOURCE_GROUP;
                                toptname = (*cmd == 'j') ?
                                    "MCAST_JOIN_SOURCE_GROUP":
                                    "MCAST_LEAVE_SOURCE_GROUP";
                                optval = (void *)&mr.gr;
                                optlen = sizeof(mr.gr);
                        } else {
                                mr.mr6.ipv6mr_multiaddr = su.sin6.sin6_addr;
                                mr.mr6.ipv6mr_interface = ifindex;
                                optname = (*cmd == 'j') ?
                                    IPV6_JOIN_GROUP :
                                    IPV6_LEAVE_GROUP;
                                toptname = (*cmd == 'j') ?
                                    "IPV6_JOIN_GROUP" :
                                    "IPV6_LEAVE_GROUP";
                                optval = (void *)&mr.mr6;
                                optlen = sizeof(mr.mr6);
                        }
                        if (s6 < 0) {
                                warnc(EPROTONOSUPPORT, "setsockopt %s",
                                    toptname);
                        } else if (setsockopt(s6, level, optname, optval,
                            optlen) == 0) {
                                printf("ok\n");
                                break;
                        } else {
                                warn("setsockopt %s", toptname);
                        }
                }
#endif /* INET6 */
                /* FALLTHROUGH */
                printf("-1\n");
                break;

        /*
         * Set the socket to include or exclude filter mode, and
         * add some sources to the filterlist, using the full-state API.
         */
        case 'i':
        case 'e': {
                sockunion_t      sources[MAX_ADDRS];
                struct addrinfo  hints;
                struct addrinfo *res;
                char            *cp;
                int              af1;

                n = 0;
                fmode = (*cmd == 'i') ? MCAST_INCLUDE : MCAST_EXCLUDE;
                if ((sscanf(line, "%s %s %d", str1, str2, &n)) != 3) {
                        printf("-1\n");
                        break;
                }

                ifindex = parse_cmd_args(&su, NULL, str1, str2, NULL);
                if (ifindex == 0 || n < 0 || n > MAX_ADDRS) {
                        printf("-1\n");
                        break;
                }
                af = su.sa.sa_family;
                if (af2sock(af, s, s6) == -1) {
                        warnc(EPROTONOSUPPORT, "setsourcefilter");
                        break;
                }

                memset(&hints, 0, sizeof(struct addrinfo));
                hints.ai_flags = AI_NUMERICHOST;
                hints.ai_family = af;
                hints.ai_socktype = SOCK_DGRAM;

                for (i = 0; i < n; i++) {
                        sockunion_t *psu = (sockunion_t *)&sources[i];
                        /*
                         * Trim trailing whitespace, as getaddrinfo()
                         * can't cope with it.
                         */
                        fgets(str1, sizeof(str1), fp);
                        cp = strchr(str1, '\n');
                        if (cp != NULL)
                                *cp = '\0';

                        res = NULL;
                        error = getaddrinfo(str1, "0", &hints, &res);
                        if (error)
                                break;
                        assert(res != NULL);

                        memset(psu, 0, sizeof(sockunion_t));
                        af1 = res->ai_family;
                        if (af1 == af)
                                memcpy(psu, res->ai_addr, res->ai_addrlen);
                        freeaddrinfo(res);
                        if (af1 != af)
                                break;
                }
                if (i < n) {
                        if (error)
                                warnx("getaddrinfo: %s", gai_strerror(error));
                        printf("-1\n");
                        break;
                }
                if (setsourcefilter(af2sock(af, s, s6), ifindex,
                    &su.sa, su.sa.sa_len, fmode, n, &sources[0].ss) != 0)
                        warn("setsourcefilter");
                else
                        printf("ok\n");
        } break;

        /*
         * Allow or block traffic from a source, using the
         * delta based api.
         */
        case 't':
        case 'b': {
                str3[0] = '\0';
                toptname = "";
                sscanf(line, "%s %s %s", str1, str2, str3);
                ifindex = parse_cmd_args(&su, &su2, str1, str2, str3);
                if (ifindex == 0 || su2.sa.sa_family == AF_UNSPEC) {
                        printf("-1\n");
                        break;
                }
                af = su.sa.sa_family;
                if (af2sock(af, s, s6) == -1) {
                        warnc(EPROTONOSUPPORT, "getsourcefilter");
                        break;
                }

                /* First determine our current filter mode. */
                if (getsourcefilter(af2sock(af, s, s6), ifindex,
                    &su.sa, su.sa.sa_len, &fmode, &n, NULL) != 0) {
                        warn("getsourcefilter");
                        break;
                }
#ifdef INET
                if (af == AF_INET) {
                        struct in_addr ina;

                        error = __ifindex_to_primary_ip(ifindex, &ina);
                        if (error != 0) {
                                warn("primary_ip_lookup %s", str2);
                                printf("-1\n");
                                break;
                        }
                        level = IPPROTO_IP;
                        optval = (void *)&mr.mrs;
                        optlen = sizeof(mr.mrs);
                        mr.mrs.imr_multiaddr = su.sin.sin_addr;
                        mr.mrs.imr_sourceaddr = su2.sin.sin_addr;
                        mr.mrs.imr_interface = ina;
                        if (fmode == MCAST_EXCLUDE) {
                                /* Any-source mode socket membership. */
                                optname = (*cmd == 't') ?
                                    IP_UNBLOCK_SOURCE :
                                    IP_BLOCK_SOURCE;
                                toptname = (*cmd == 't') ?
                                    "IP_UNBLOCK_SOURCE" :
                                    "IP_BLOCK_SOURCE";
                        } else {
                                /* Source-specific mode socket membership. */
                                optname = (*cmd == 't') ?
                                    IP_ADD_SOURCE_MEMBERSHIP :
                                    IP_DROP_SOURCE_MEMBERSHIP;
                                toptname = (*cmd == 't') ?
                                    "IP_ADD_SOURCE_MEMBERSHIP" :
                                    "IP_DROP_SOURCE_MEMBERSHIP";
                        }
                        if (setsockopt(s, level, optname, optval,
                            optlen) == 0) {
                                printf("ok\n");
                                break;
                        } else {
                                warn("setsockopt %s", toptname);
                        }
                }
#ifdef INET6
                else
#endif /* INET with INET6 */
#endif /* INET */
#ifdef INET6
                if (af == AF_INET6) {
                        level = IPPROTO_IPV6;
                        mr.gr.gsr_interface = ifindex;
                        mr.gr.gsr_group = su.ss;
                        mr.gr.gsr_source = su2.ss;
                        if (fmode == MCAST_EXCLUDE) {
                                /* Any-source mode socket membership. */
                                optname = (*cmd == 't') ?
                                    MCAST_UNBLOCK_SOURCE :
                                    MCAST_BLOCK_SOURCE;
                                toptname = (*cmd == 't') ?
                                    "MCAST_UNBLOCK_SOURCE" :
                                    "MCAST_BLOCK_SOURCE";
                        } else {
                                /* Source-specific mode socket membership. */
                                optname = (*cmd == 't') ?
                                    MCAST_JOIN_SOURCE_GROUP :
                                    MCAST_LEAVE_SOURCE_GROUP;
                                toptname = (*cmd == 't') ?
                                    "MCAST_JOIN_SOURCE_GROUP":
                                    "MCAST_LEAVE_SOURCE_GROUP";
                        }
                        optval = (void *)&mr.gr;
                        optlen = sizeof(mr.gr);
                        if (setsockopt(s6, level, optname, optval,
                            optlen) == 0) {
                                printf("ok\n");
                                break;
                        } else {
                                warn("setsockopt %s", toptname);
                        }
                }
#endif /* INET6 */
                /* FALLTHROUGH */
                printf("-1\n");
        } break;

        case 'g': {
                sockunion_t      sources[MAX_ADDRS];
                char             addrbuf[NI_MAXHOST];
                int              nreqsrc, nsrc;

                if ((sscanf(line, "%s %s %d", str1, str2, &nreqsrc)) != 3) {
                        printf("-1\n");
                        break;
                }
                ifindex = parse_cmd_args(&su, NULL, str1, str2, NULL);
                if (ifindex == 0 || (n < 0 || n > MAX_ADDRS)) {
                        printf("-1\n");
                        break;
                }

                af = su.sa.sa_family;
                if (af2sock(af, s, s6) == -1) {
                        warnc(EPROTONOSUPPORT, "getsourcefilter");
                        break;
                }
                nsrc = nreqsrc;
                if (getsourcefilter(af2sock(af, s, s6), ifindex, &su.sa,
                    su.sa.sa_len, &fmode, &nsrc, &sources[0].ss) != 0) {
                        warn("getsourcefilter");
                        printf("-1\n");
                        break;
                }
                printf("%s\n", (fmode == MCAST_INCLUDE) ? "include" :
                    "exclude");
                printf("%d\n", nsrc);

                nsrc = MIN(nreqsrc, nsrc);
                fprintf(stderr, "hexdump of sources:\n");
                uint8_t *bp = (uint8_t *)&sources[0];
                for (j = 0; j < (nsrc * sizeof(sources[0])); j++) {
                        fprintf(stderr, "%02x", bp[j]);
                }
                fprintf(stderr, "\nend hexdump\n");

                qsort(sources, nsrc, af2socklen(af), su_cmp);
                for (i = 0; i < nsrc; i++) {
                        sockunion_t *psu = (sockunion_t *)&sources[i];
                        addrbuf[0] = '\0';
                        error = getnameinfo(&psu->sa, psu->sa.sa_len,
                            addrbuf, sizeof(addrbuf), NULL, 0,
                            NI_NUMERICHOST);
                        if (error)
                                warnx("getnameinfo: %s", gai_strerror(error));
                        else
                                printf("%s\n", addrbuf);
                }
                printf("ok\n");
        } break;

        /* link-layer stuff follows. */

        case 'a':
        case 'd': {
                struct sockaddr_dl      *dlp;
                struct ether_addr       *ep;

                memset(&ifr, 0, sizeof(struct ifreq));
                dlp = (struct sockaddr_dl *)&ifr.ifr_addr;
                dlp->sdl_len = sizeof(struct sockaddr_dl);
                dlp->sdl_family = AF_LINK;
                dlp->sdl_index = 0;
                dlp->sdl_nlen = 0;
                dlp->sdl_alen = ETHER_ADDR_LEN;
                dlp->sdl_slen = 0;
                if (sscanf(line, "%s %s", str1, str2) != 2) {
                        warnc(EINVAL, "sscanf");
                        break;
                }
                ep = ether_aton(str2);
                if (ep == NULL) {
                        warnc(EINVAL, "ether_aton");
                        break;
                }
                strlcpy(ifr.ifr_name, str1, IF_NAMESIZE);
                memcpy(LLADDR(dlp), ep, ETHER_ADDR_LEN);
                if (ioctl(s, (*cmd == 'a') ? SIOCADDMULTI : SIOCDELMULTI,
                    &ifr) == -1) {
                        warn("ioctl SIOCADDMULTI/SIOCDELMULTI");
                        printf("-1\n");
                } else
                        printf("ok\n");
                break;
        }

        case 'm':
                fprintf(stderr,
                    "warning: IFF_ALLMULTI cannot be set from userland "
                    "in FreeBSD; command ignored.\n");
                printf("-1\n");
                break;

        case 'p':
                if (sscanf(line, "%s %u", ifr.ifr_name, &f) != 2) {
                        printf("-1\n");
                        break;
                }
                if (ioctl(s, SIOCGIFFLAGS, &ifr) == -1) {
                        warn("ioctl SIOCGIFFLAGS");
                        break;
                }
                flags = (ifr.ifr_flags & 0xffff) | (ifr.ifr_flagshigh << 16);
                if (f == 0) {
                        flags &= ~IFF_PPROMISC;
                } else {
                        flags |= IFF_PPROMISC;
                }
                ifr.ifr_flags = flags & 0xffff;
                ifr.ifr_flagshigh = flags >> 16;
                if (ioctl(s, SIOCSIFFLAGS, &ifr) == -1)
                        warn("ioctl SIOCGIFFLAGS");
                else
                        printf( "changed to 0x%08x\n", flags );
                break;

        case '\n':
                break;
        default:
                printf("invalid command\n");
                break;
        }
}

static void
usage(void)
{

        printf("j mcast-addr ifname [src-addr] - join IP multicast group\n");
        printf("l mcast-addr ifname [src-addr] - leave IP multicast group\n");
        printf(
"i mcast-addr ifname n          - set n include mode src filter\n");
        printf(
"e mcast-addr ifname n          - set n exclude mode src filter\n");
        printf("t mcast-addr ifname src-addr  - allow traffic from src\n");
        printf("b mcast-addr ifname src-addr  - block traffic from src\n");
        printf("g mcast-addr ifname n        - get and show n src filters\n");
        printf("a ifname mac-addr          - add link multicast filter\n");
        printf("d ifname mac-addr          - delete link multicast filter\n");
        printf("m ifname 1/0               - set/clear ether allmulti flag\n");
        printf("p ifname 1/0               - set/clear ether promisc flag\n");
        printf("f filename                 - read command(s) from file\n");
        printf("s seconds                  - sleep for some time\n");
        printf("q                          - quit\n");
}