/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1983, 1993, 1994
 *      The Regents of the University of California.  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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

#include "namespace.h"
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <signal.h>
#include <fcntl.h>
#include <netdb.h>
#include <stdlib.h>
#include <unistd.h>
#include <pwd.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <rpc/rpc.h>
#ifdef YP
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
#endif
#include <arpa/nameser.h>
#include "un-namespace.h"
#include "libc_private.h"

extern int innetgr( const char *, const char *, const char *, const char * );

#define max(a, b)       ((a > b) ? a : b)

int __ivaliduser(FILE *, u_int32_t, const char *, const char *);
int __ivaliduser_af(FILE *,const void *, const char *, const char *, int, int);
int __ivaliduser_sa(FILE *, const struct sockaddr *, socklen_t, const char *,
    const char *);
static int __icheckhost(const struct sockaddr *, socklen_t, const char *);

char paddr[NI_MAXHOST];

int
rcmd(char **ahost, int rport, const char *locuser, const char *remuser,
    const char *cmd, int *fd2p)
{
        return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
}

int
rcmd_af(char **ahost, int rport, const char *locuser, const char *remuser,
    const char *cmd, int *fd2p, int af)
{
        struct addrinfo hints, *res, *ai;
        struct sockaddr_storage from;
        fd_set reads;
        sigset_t oldmask, newmask;
        pid_t pid;
        int s, aport, lport, timo, error;
        char c, *p;
        int refused, nres;
        char num[8];
        static char canonnamebuf[MAXDNAME];     /* is it proper here? */

        /* call rcmdsh() with specified remote shell if appropriate. */
        if ((p = secure_getenv("RSH")) != NULL) {
                struct servent *sp = getservbyname("shell", "tcp");

                if (sp && sp->s_port == rport)
                        return (rcmdsh(ahost, rport, locuser, remuser,
                            cmd, p));
        }

        /* use rsh(1) if non-root and remote port is shell. */
        if (geteuid()) {
                struct servent *sp = getservbyname("shell", "tcp");

                if (sp && sp->s_port == rport)
                        return (rcmdsh(ahost, rport, locuser, remuser,
                            cmd, NULL));
        }

        pid = getpid();

        memset(&hints, 0, sizeof(hints));
        hints.ai_flags = AI_CANONNAME;
        hints.ai_family = af;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_protocol = 0;
        (void)snprintf(num, sizeof(num), "%d", ntohs(rport));
        error = getaddrinfo(*ahost, num, &hints, &res);
        if (error) {
                fprintf(stderr, "rcmd: getaddrinfo: %s\n",
                        gai_strerror(error));
                if (error == EAI_SYSTEM)
                        fprintf(stderr, "rcmd: getaddrinfo: %s\n",
                                strerror(errno));
                return (-1);
        }

        if (res->ai_canonname
         && strlen(res->ai_canonname) + 1 < sizeof(canonnamebuf)) {
                strncpy(canonnamebuf, res->ai_canonname, sizeof(canonnamebuf));
                *ahost = canonnamebuf;
        }
        nres = 0;
        for (ai = res; ai; ai = ai->ai_next)
                nres++;
        ai = res;
        refused = 0;
        sigemptyset(&newmask);
        sigaddset(&newmask, SIGURG);
        __libc_sigprocmask(SIG_BLOCK, (const sigset_t *)&newmask, &oldmask);
        for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
                s = rresvport_af(&lport, ai->ai_family);
                if (s < 0) {
                        if (errno != EAGAIN && ai->ai_next) {
                                ai = ai->ai_next;
                                continue;
                        }
                        if (errno == EAGAIN)
                                (void)fprintf(stderr,
                                    "rcmd: socket: All ports in use\n");
                        else
                                (void)fprintf(stderr, "rcmd: socket: %s\n",
                                    strerror(errno));
                        freeaddrinfo(res);
                        __libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
                            NULL);
                        return (-1);
                }
                _fcntl(s, F_SETOWN, pid);
                if (_connect(s, ai->ai_addr, ai->ai_addrlen) >= 0)
                        break;
                (void)_close(s);
                if (errno == EADDRINUSE) {
                        lport--;
                        continue;
                }
                if (errno == ECONNREFUSED)
                        refused = 1;
                if (ai->ai_next == NULL && (!refused || timo > 16)) {
                        (void)fprintf(stderr, "%s: %s\n",
                                      *ahost, strerror(errno));
                        freeaddrinfo(res);
                        __libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
                            NULL);
                        return (-1);
                }
                if (nres > 1) {
                        int oerrno = errno;

                        getnameinfo(ai->ai_addr, ai->ai_addrlen, paddr,
                            sizeof(paddr), NULL, 0, NI_NUMERICHOST);
                        (void)fprintf(stderr, "connect to address %s: ",
                                      paddr);
                        errno = oerrno;
                        perror(0);
                }
                if ((ai = ai->ai_next) == NULL) {
                        /* refused && timo <= 16 */
                        struct timespec time_to_sleep, time_remaining;

                        time_to_sleep.tv_sec = timo;
                        time_to_sleep.tv_nsec = 0;
                        (void)_nanosleep(&time_to_sleep, &time_remaining);
                        timo *= 2;
                        ai = res;
                        refused = 0;
                }
                if (nres > 1) {
                        getnameinfo(ai->ai_addr, ai->ai_addrlen, paddr,
                            sizeof(paddr), NULL, 0, NI_NUMERICHOST);
                        fprintf(stderr, "Trying %s...\n", paddr);
                }
        }
        lport--;
        if (fd2p == NULL) {
                _write(s, "", 1);
                lport = 0;
        } else {
                int s2 = rresvport_af(&lport, ai->ai_family), s3;
                socklen_t len = ai->ai_addrlen;
                int nfds;

                if (s2 < 0)
                        goto bad;
                _listen(s2, 1);
                (void)snprintf(num, sizeof(num), "%d", lport);
                if (_write(s, num, strlen(num)+1) != strlen(num)+1) {
                        (void)fprintf(stderr,
                            "rcmd: write (setting up stderr): %s\n",
                            strerror(errno));
                        (void)_close(s2);
                        goto bad;
                }
                nfds = max(s, s2)+1;
                if(nfds > FD_SETSIZE) {
                        fprintf(stderr, "rcmd: too many files\n");
                        (void)_close(s2);
                        goto bad;
                }
again:
                FD_ZERO(&reads);
                FD_SET(s, &reads);
                FD_SET(s2, &reads);
                errno = 0;
                if (_select(nfds, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)){
                        if (errno != 0)
                                (void)fprintf(stderr,
                                    "rcmd: select (setting up stderr): %s\n",
                                    strerror(errno));
                        else
                                (void)fprintf(stderr,
                                "select: protocol failure in circuit setup\n");
                        (void)_close(s2);
                        goto bad;
                }
                s3 = _accept(s2, (struct sockaddr *)&from, &len);
                switch (from.ss_family) {
                case AF_INET:
                        aport = ntohs(((struct sockaddr_in *)&from)->sin_port);
                        break;
#ifdef INET6
                case AF_INET6:
                        aport = ntohs(((struct sockaddr_in6 *)&from)->sin6_port);
                        break;
#endif
                default:
                        aport = 0;      /* error */
                        break;
                }
                /*
                 * XXX careful for ftp bounce attacks. If discovered, shut them
                 * down and check for the real auxiliary channel to connect.
                 */
                if (aport == 20) {
                        _close(s3);
                        goto again;
                }
                (void)_close(s2);
                if (s3 < 0) {
                        (void)fprintf(stderr,
                            "rcmd: accept: %s\n", strerror(errno));
                        lport = 0;
                        goto bad;
                }
                *fd2p = s3;
                if (aport >= IPPORT_RESERVED || aport < IPPORT_RESERVED / 2) {
                        (void)fprintf(stderr,
                            "socket: protocol failure in circuit setup.\n");
                        goto bad2;
                }
        }
        (void)_write(s, locuser, strlen(locuser)+1);
        (void)_write(s, remuser, strlen(remuser)+1);
        (void)_write(s, cmd, strlen(cmd)+1);
        if (_read(s, &c, 1) != 1) {
                (void)fprintf(stderr,
                    "rcmd: %s: %s\n", *ahost, strerror(errno));
                goto bad2;
        }
        if (c != 0) {
                while (_read(s, &c, 1) == 1) {
                        (void)_write(STDERR_FILENO, &c, 1);
                        if (c == '\n')
                                break;
                }
                goto bad2;
        }
        __libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
        freeaddrinfo(res);
        return (s);
bad2:
        if (lport)
                (void)_close(*fd2p);
bad:
        (void)_close(s);
        __libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
        freeaddrinfo(res);
        return (-1);
}

int
rresvport(int *port)
{
        return rresvport_af(port, AF_INET);
}

int
rresvport_af(int *alport, int family)
{
        int s;
        struct sockaddr_storage ss;
        u_short *sport;

        memset(&ss, 0, sizeof(ss));
        ss.ss_family = family;
        switch (family) {
        case AF_INET:
                ((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in);
                sport = &((struct sockaddr_in *)&ss)->sin_port;
                ((struct sockaddr_in *)&ss)->sin_addr.s_addr = INADDR_ANY;
                break;
#ifdef INET6
        case AF_INET6:
                ((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in6);
                sport = &((struct sockaddr_in6 *)&ss)->sin6_port;
                ((struct sockaddr_in6 *)&ss)->sin6_addr = in6addr_any;
                break;
#endif
        default:
                errno = EAFNOSUPPORT;
                return -1;
        }

        s = _socket(ss.ss_family, SOCK_STREAM, 0);
        if (s < 0)
                return (-1);
#if 0 /* compat_exact_traditional_rresvport_semantics */
        sin.sin_port = htons((u_short)*alport);
        if (_bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
                return (s);
        if (errno != EADDRINUSE) {
                (void)_close(s);
                return (-1);
        }
#endif
        *sport = 0;
        if (bindresvport_sa(s, (struct sockaddr *)&ss) == -1) {
                (void)_close(s);
                return (-1);
        }
        *alport = (int)ntohs(*sport);
        return (s);
}

int     __check_rhosts_file = 1;
char    *__rcmd_errstr;

int
ruserok(const char *rhost, int superuser, const char *ruser, const char *luser)
{
        struct addrinfo hints, *res, *r;
        int error;

        memset(&hints, 0, sizeof(hints));
        hints.ai_family = PF_UNSPEC;
        hints.ai_socktype = SOCK_DGRAM; /*dummy*/
        error = getaddrinfo(rhost, "0", &hints, &res);
        if (error)
                return (-1);

        for (r = res; r; r = r->ai_next) {
                if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser,
                    luser) == 0) {
                        freeaddrinfo(res);
                        return (0);
                }
        }
        freeaddrinfo(res);
        return (-1);
}

/*
 * New .rhosts strategy: We are passed an ip address. We spin through
 * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 * has ip addresses, we don't have to trust a nameserver.  When it
 * contains hostnames, we spin through the list of addresses the nameserver
 * gives us and look for a match.
 *
 * Returns 0 if ok, -1 if not ok.
 */
int
iruserok(unsigned long raddr, int superuser, const char *ruser, const char *luser)
{
        struct sockaddr_in sin;

        memset(&sin, 0, sizeof(sin));
        sin.sin_family = AF_INET;
        sin.sin_len = sizeof(struct sockaddr_in);
        memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
        return iruserok_sa((struct sockaddr *)&sin, sin.sin_len, superuser,
                ruser, luser);
}

/*
 * AF independent extension of iruserok.
 *
 * Returns 0 if ok, -1 if not ok.
 */
int
iruserok_sa(const void *ra, int rlen, int superuser, const char *ruser,
    const char *luser)
{
        char *cp;
        struct stat sbuf;
        struct passwd *pwd;
        FILE *hostf;
        uid_t uid;
        int first;
        char pbuf[MAXPATHLEN];
        const struct sockaddr *raddr;
        struct sockaddr_storage ss;

        /* avoid alignment issue */
        if (rlen <= 0 || rlen > sizeof(ss))
                return (-1);
        memcpy(&ss, ra, rlen);
        raddr = (struct sockaddr *)&ss;

        first = 1;
        hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "re");
again:
        if (hostf) {
                if (__ivaliduser_sa(hostf, raddr, rlen, luser, ruser) == 0) {
                        (void)fclose(hostf);
                        return (0);
                }
                (void)fclose(hostf);
        }
        if (first == 1 && (__check_rhosts_file || superuser)) {
                first = 0;
                if ((pwd = getpwnam(luser)) == NULL)
                        return (-1);
                (void)strlcpy(pbuf, pwd->pw_dir, sizeof(pbuf));
                (void)strlcat(pbuf, "/.rhosts", sizeof(pbuf));

                /*
                 * Change effective uid while opening .rhosts.  If root and
                 * reading an NFS mounted file system, can't read files that
                 * are protected read/write owner only.
                 */
                uid = geteuid();
                (void)seteuid(pwd->pw_uid);
                hostf = fopen(pbuf, "re");
                (void)seteuid(uid);

                if (hostf == NULL)
                        return (-1);
                /*
                 * If not a regular file, or is owned by someone other than
                 * user or root or if writeable by anyone but the owner, quit.
                 */
                cp = NULL;
                if (lstat(pbuf, &sbuf) < 0)
                        cp = ".rhosts lstat failed";
                else if (!S_ISREG(sbuf.st_mode))
                        cp = ".rhosts not regular file";
                else if (_fstat(fileno(hostf), &sbuf) < 0)
                        cp = ".rhosts fstat failed";
                else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
                        cp = "bad .rhosts owner";
                else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
                        cp = ".rhosts writeable by other than owner";
                /* If there were any problems, quit. */
                if (cp) {
                        __rcmd_errstr = cp;
                        (void)fclose(hostf);
                        return (-1);
                }
                goto again;
        }
        return (-1);
}

/*
 * XXX
 * Don't make static, used by lpd(8).
 *
 * Returns 0 if ok, -1 if not ok.
 */
int
__ivaliduser(FILE *hostf, u_int32_t raddr, const char *luser, const char *ruser)
{
        struct sockaddr_in sin;

        memset(&sin, 0, sizeof(sin));
        sin.sin_family = AF_INET;
        sin.sin_len = sizeof(struct sockaddr_in);
        memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
        return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, sin.sin_len,
                luser, ruser);
}

/*
 * Returns 0 if ok, -1 if not ok.
 *
 * XXX obsolete API.
 */
int
__ivaliduser_af(FILE *hostf, const void *raddr, const char *luser,
    const char *ruser, int af, int len)
{
        struct sockaddr *sa = NULL;
        struct sockaddr_in *sin = NULL;
#ifdef INET6
        struct sockaddr_in6 *sin6 = NULL;
#endif
        struct sockaddr_storage ss;

        memset(&ss, 0, sizeof(ss));
        switch (af) {
        case AF_INET:
                if (len != sizeof(sin->sin_addr))
                        return -1;
                sin = (struct sockaddr_in *)&ss;
                sin->sin_family = AF_INET;
                sin->sin_len = sizeof(struct sockaddr_in);
                memcpy(&sin->sin_addr, raddr, sizeof(sin->sin_addr));
                break;
#ifdef INET6
        case AF_INET6:
                if (len != sizeof(sin6->sin6_addr))
                        return -1;
                /* you will lose scope info */
                sin6 = (struct sockaddr_in6 *)&ss;
                sin6->sin6_family = AF_INET6;
                sin6->sin6_len = sizeof(struct sockaddr_in6);
                memcpy(&sin6->sin6_addr, raddr, sizeof(sin6->sin6_addr));
                break;
#endif
        default:
                return -1;
        }

        sa = (struct sockaddr *)&ss;
        return __ivaliduser_sa(hostf, sa, sa->sa_len, luser, ruser);
}

int
__ivaliduser_sa(FILE *hostf, const struct sockaddr *raddr, socklen_t salen,
    const char *luser, const char *ruser)
{
        char *user, *p;
        int ch;
        char buf[MAXHOSTNAMELEN + 128];         /* host + login */
        char hname[MAXHOSTNAMELEN];
        /* Presumed guilty until proven innocent. */
        int userok = 0, hostok = 0;
#ifdef YP
        char *ypdomain;

        if (yp_get_default_domain(&ypdomain))
                ypdomain = NULL;
#else
#define ypdomain NULL
#endif
        /* We need to get the damn hostname back for netgroup matching. */
        if (getnameinfo(raddr, salen, hname, sizeof(hname), NULL, 0,
                        NI_NAMEREQD) != 0)
                hname[0] = '\0';

        while (fgets(buf, sizeof(buf), hostf)) {
                p = buf;
                /* Skip lines that are too long. */
                if (strchr(p, '\n') == NULL) {
                        while ((ch = getc(hostf)) != '\n' && ch != EOF);
                        continue;
                }
                if (*p == '\n' || *p == '#') {
                        /* comment... */
                        continue;
                }
                while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
                        *p = isupper((unsigned char)*p) ? tolower((unsigned char)*p) : *p;
                        p++;
                }
                if (*p == ' ' || *p == '\t') {
                        *p++ = '\0';
                        while (*p == ' ' || *p == '\t')
                                p++;
                        user = p;
                        while (*p != '\n' && *p != ' ' &&
                            *p != '\t' && *p != '\0')
                                p++;
                } else
                        user = p;
                *p = '\0';
                /*
                 * Do +/- and +@/-@ checking. This looks really nasty,
                 * but it matches SunOS's behavior so far as I can tell.
                 */
                switch(buf[0]) {
                case '+':
                        if (!buf[1]) {     /* '+' matches all hosts */
                                hostok = 1;
                                break;
                        }
                        if (buf[1] == '@')  /* match a host by netgroup */
                                hostok = hname[0] != '\0' &&
                                    innetgr(&buf[2], hname, NULL, ypdomain);
                        else            /* match a host by addr */
                                hostok = __icheckhost(raddr, salen,
                                                      (char *)&buf[1]);
                        break;
                case '-':     /* reject '-' hosts and all their users */
                        if (buf[1] == '@') {
                                if (hname[0] == '\0' ||
                                    innetgr(&buf[2], hname, NULL, ypdomain))
                                        return(-1);
                        } else {
                                if (__icheckhost(raddr, salen,
                                                 (char *)&buf[1]))
                                        return(-1);
                        }
                        break;
                default:  /* if no '+' or '-', do a simple match */
                        hostok = __icheckhost(raddr, salen, buf);
                        break;
                }
                switch(*user) {
                case '+':
                        if (!*(user+1)) {      /* '+' matches all users */
                                userok = 1;
                                break;
                        }
                        if (*(user+1) == '@')  /* match a user by netgroup */
                                userok = innetgr(user+2, NULL, ruser, ypdomain);
                        else       /* match a user by direct specification */
                                userok = !(strcmp(ruser, user+1));
                        break;
                case '-':               /* if we matched a hostname, */
                        if (hostok) {   /* check for user field rejections */
                                if (!*(user+1))
                                        return(-1);
                                if (*(user+1) == '@') {
                                        if (innetgr(user+2, NULL,
                                                        ruser, ypdomain))
                                                return(-1);
                                } else {
                                        if (!strcmp(ruser, user+1))
                                                return(-1);
                                }
                        }
                        break;
                default:        /* no rejections: try to match the user */
                        if (hostok)
                                userok = !(strcmp(ruser,*user ? user : luser));
                        break;
                }
                if (hostok && userok)
                        return(0);
        }
        return (-1);
}

/*
 * Returns "true" if match, 0 if no match.
 */
static int
__icheckhost(const struct sockaddr *raddr, socklen_t salen, const char *lhost)
{
        struct sockaddr_in sin;
        struct sockaddr_in6 *sin6;
        struct addrinfo hints, *res, *r;
        int error;
        char h1[NI_MAXHOST], h2[NI_MAXHOST];

        if (raddr->sa_family == AF_INET6) {
                sin6 = (struct sockaddr_in6 *)raddr;
                if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
                        memset(&sin, 0, sizeof(sin));
                        sin.sin_family = AF_INET;
                        sin.sin_len = sizeof(struct sockaddr_in);
                        memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[12],
                               sizeof(sin.sin_addr));
                        raddr = (struct sockaddr *)&sin;
                        salen = sin.sin_len;
                }
        }

        h1[0] = '\0';
        if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0,
                        NI_NUMERICHOST) != 0)
                return (0);

        /* Resolve laddr into sockaddr */
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = raddr->sa_family;
        hints.ai_socktype = SOCK_DGRAM; /*XXX dummy*/
        res = NULL;
        error = getaddrinfo(lhost, "0", &hints, &res);
        if (error)
                return (0);

        for (r = res; r ; r = r->ai_next) {
                h2[0] = '\0';
                if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2),
                                NULL, 0, NI_NUMERICHOST) != 0)
                        continue;
                if (strcmp(h1, h2) == 0) {
                        freeaddrinfo(res);
                        return (1);
                }
        }

        /* No match. */
        freeaddrinfo(res);
        return (0);
}