/*      $NetBSD: getnetnamadr.c,v 1.44 2015/10/26 19:41:19 christos Exp $       */

/* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
 *      Dep. Matematica Universidade de Coimbra, Portugal, Europe
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 */
/*
 * Copyright (c) 1983, 1993
 *      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 <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)getnetbyaddr.c      8.1 (Berkeley) 6/4/93";
static char sccsid_[] = "from getnetnamadr.c    1.4 (Coimbra) 93/06/03";
static char rcsid[] = "Id: getnetnamadr.c,v 8.8 1997/06/01 20:34:37 vixie Exp ";
#else
__RCSID("$NetBSD: getnetnamadr.c,v 1.44 2015/10/26 19:41:19 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <nsswitch.h>
#include <resolv.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef YP
#include <rpc/rpc.h>
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
#endif

#ifdef __weak_alias
__weak_alias(getnetbyaddr,_getnetbyaddr)
__weak_alias(getnetbyname,_getnetbyname)
#endif

#define maybe_ok(res, nm, ok) (((res)->options & RES_NOCHECKNAME) != 0U || \
                               (ok)(nm) != 0)
#define maybe_hnok(res, hn) maybe_ok((res), (hn), res_hnok)
#define maybe_dnok(res, dn) maybe_ok((res), (dn), res_dnok)


extern int _net_stayopen;

#define BYADDR 0
#define BYNAME 1
#define MAXALIASES      35

#define MAXPACKET       (64*1024)

typedef union {
        HEADER  hdr;
        u_char  buf[MAXPACKET];
} querybuf;

typedef union {
        long    al;
        char    ac;
} align;

#ifdef YP
static char *__ypdomain;
static char *__ypcurrent;
static int   __ypcurrentlen;
#endif

static  struct netent net_entry;
static  char *net_aliases[MAXALIASES];

static int              parse_reversed_addr(const char *, in_addr_t *);
static struct netent    *getnetanswer(res_state, querybuf *, int, int);
static int              _files_getnetbyaddr(void *, void *, va_list);
static int              _files_getnetbyname(void *, void *, va_list);
static int              _dns_getnetbyaddr(void *, void *, va_list);
static int              _dns_getnetbyname(void *, void *, va_list);
#ifdef YP
static int              _yp_getnetbyaddr(void *, void *, va_list);
static int              _yp_getnetbyname(void *, void *, va_list);
static struct netent    *_ypnetent(char *);
#endif

/*
 * parse_reversed_addr --
 *      parse str, which should be of the form 'd.c.b.a.IN-ADDR.ARPA'
 *      (a PTR as per RFC 1101) and convert into an in_addr_t of the
 *      address 'a.b.c.d'.
 *      returns 0 on success (storing in *result), or -1 on error.
 */
static int
parse_reversed_addr(const char *str, in_addr_t *result)
{
        unsigned long   octet[4];
        const char      *sp;
        char            *ep;
        int             octidx;

        sp = str;
                                /* find the four octets 'd.b.c.a.' */
        for (octidx = 0; octidx < 4; octidx++) {
                                        /* ensure it's a number */
                if (!isdigit((unsigned char)*sp))
                        return -1;
                octet[octidx] = strtoul(sp, &ep, 10);
                                        /* with a trailing '.' */
                if (*ep != '.')
                        return -1;
                                        /* and is 0 <= octet <= 255 */
                if (octet[octidx] > 255)
                        return -1;
                sp = ep + 1;
        }
                                /* ensure trailer is correct */
        if (strcasecmp(sp, "IN-ADDR.ARPA") != 0)
                return -1;
        *result = 0;
                                /* build result from octets in reverse */
        for (octidx = 3; octidx >= 0; octidx--) {
                *result <<= 8;
                *result |= (in_addr_t)(octet[octidx] & 0xff);
        }
        return 0;
}

static struct netent *
getnetanswer(res_state res, querybuf *answer, int anslen, int net_i)
{
        static char     n_name[MAXDNAME];
        static char     netbuf[PACKETSZ];

        HEADER          *hp;
        u_char          *cp;
        int             n;
        u_char          *eom;
        int             type, class, ancount, qdcount, haveanswer;
        char            *in, *bp, **ap, *ep;

        _DIAGASSERT(answer != NULL);
        _DIAGASSERT(res != NULL);

        /*
         * find first satisfactory answer
         *
         *      answer --> +------------+  ( MESSAGE )
         *                 |   Header   |
         *                 +------------+
         *                 |  Question  | the question for the name server
         *                 +------------+
         *                 |   Answer   | RRs answering the question
         *                 +------------+
         *                 | Authority  | RRs pointing toward an authority
         *                 | Additional | RRs holding additional information
         *                 +------------+
         */
        eom = answer->buf + anslen;
        hp = &answer->hdr;
        ancount = ntohs(hp->ancount); /* #/records in the answer section */
        qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
        bp = netbuf;
        ep = netbuf + sizeof(netbuf);
        cp = answer->buf + HFIXEDSZ;
        if (!qdcount) {
                if (hp->aa)
                        h_errno = HOST_NOT_FOUND;
                else
                        h_errno = TRY_AGAIN;
                return NULL;
        }
        while (qdcount-- > 0) {
                n = __dn_skipname(cp, eom);
                if (n < 0 || (cp + n + QFIXEDSZ) > eom) {
                        h_errno = NO_RECOVERY;
                        return(NULL);
                }
                cp += n + QFIXEDSZ;
        }
        ap = net_aliases;
        *ap = NULL;
        net_entry.n_aliases = net_aliases;
        haveanswer = 0;
        n_name[0] = '\0';
        while (--ancount >= 0 && cp < eom) {
                n = dn_expand(answer->buf, eom, cp, bp, (int)(ep - bp));
                if ((n < 0) || !maybe_dnok(res, bp))
                        break;
                cp += n;
                (void)strlcpy(n_name, bp, sizeof(n_name));
                GETSHORT(type, cp);
                GETSHORT(class, cp);
                cp += INT32SZ;          /* TTL */
                GETSHORT(n, cp);
                if (class == C_IN && type == T_PTR) {
                        n = dn_expand(answer->buf, eom, cp, bp, (int)(ep - bp));
                        if ((n < 0) || !maybe_hnok(res, bp)) {
                                cp += n;
                                return NULL;
                        }
                        cp += n;
                        *ap++ = bp;
                        bp += strlen(bp) + 1;
                        net_entry.n_addrtype =
                                (class == C_IN) ? AF_INET : AF_UNSPEC;
                        haveanswer++;
                }
        }
        if (haveanswer) {
                *ap = NULL;
                switch (net_i) {
                case BYADDR:
                        net_entry.n_name = *net_entry.n_aliases;
                        net_entry.n_net = 0L;
                        break;
                case BYNAME:
                        ap = net_entry.n_aliases;
                next_alias:
                        in = *ap++;
                        if (in == NULL) {
                                h_errno = HOST_NOT_FOUND;
                                return NULL;
                        }
                        net_entry.n_name = n_name;
                        if (parse_reversed_addr(in, &net_entry.n_net) == -1)
                                goto next_alias;
                        break;
                }
                net_entry.n_aliases++;
#if (defined(__sparc__) && defined(_LP64)) ||           \
    defined(__alpha__) ||                               \
    (defined(__i386__) && defined(_LP64)) ||            \
    (defined(__sh__) && defined(_LP64))
                net_entry.__n_pad0 = 0;
#endif
                return &net_entry;
        }
        h_errno = TRY_AGAIN;
        return NULL;
}

/*ARGSUSED*/
static int
_files_getnetbyaddr(void *cbrv, void *cbdata, va_list ap)
{
        struct netent   **retval = va_arg(ap, struct netent **);
        uint32_t          net    = va_arg(ap, uint32_t);
        int               type   = va_arg(ap, int);

        struct netent    *np;

        setnetent(_net_stayopen);
        while ((np = getnetent()) != NULL)
                if (np->n_addrtype == type && np->n_net == net)
                        break;
        if (!_net_stayopen)
                endnetent();

        if (np != NULL) {
                *retval = np;
                return NS_SUCCESS;
        } else {
                h_errno = HOST_NOT_FOUND;
                return NS_NOTFOUND;
        }
}

/*ARGSUSED*/
static int
_dns_getnetbyaddr(void *cbrv, void *cbdata, va_list ap)
{
        struct netent   **retval = va_arg(ap, struct netent **);
        uint32_t          net    = va_arg(ap, uint32_t);
        int               type   = va_arg(ap, int);

        unsigned int     netbr[4];
        int              nn, anslen;
        querybuf        *buf;
        char             qbuf[MAXDNAME];
        uint32_t         net2;
        struct netent   *np;
        res_state        res;

        if (type != AF_INET)
                return NS_UNAVAIL;

        for (nn = 4, net2 = net; net2; net2 >>= 8)
                netbr[--nn] = (unsigned int)(net2 & 0xff);
        switch (nn) {
        default:
                return NS_UNAVAIL;
        case 3:         /* Class A */
                snprintf(qbuf, sizeof(qbuf), "0.0.0.%u.in-addr.arpa", netbr[3]);
                break;
        case 2:         /* Class B */
                snprintf(qbuf, sizeof(qbuf), "0.0.%u.%u.in-addr.arpa",
                    netbr[3], netbr[2]);
                break;
        case 1:         /* Class C */
                snprintf(qbuf, sizeof(qbuf), "0.%u.%u.%u.in-addr.arpa",
                    netbr[3], netbr[2], netbr[1]);
                break;
        case 0:         /* Class D - E */
                snprintf(qbuf, sizeof(qbuf), "%u.%u.%u.%u.in-addr.arpa",
                    netbr[3], netbr[2], netbr[1], netbr[0]);
                break;
        }
        buf = malloc(sizeof(*buf));
        if (buf == NULL) {
                h_errno = NETDB_INTERNAL;
                return NS_NOTFOUND;
        }
        res = __res_get_state();
        if (res == NULL) {
                free(buf);
                return NS_NOTFOUND;
        }
        anslen = res_nquery(res, qbuf, C_IN, T_PTR, buf->buf,
            (int)sizeof(buf->buf));
        if (anslen < 0) {
                free(buf);
#ifdef DEBUG
                if (res->options & RES_DEBUG)
                        printf("res_query failed\n");
#endif
                __res_put_state(res);
                return NS_NOTFOUND;
        }
        np = getnetanswer(res, buf, anslen, BYADDR);
        __res_put_state(res);
        free(buf);
        if (np) {
                /* maybe net should be unsigned? */
                uint32_t u_net = net;

                /* Strip trailing zeros */
                while ((u_net & 0xff) == 0 && u_net != 0)
                        u_net >>= 8;
                np->n_net = u_net;
        }

        if (np != NULL) {
                *retval = np;
                return NS_SUCCESS;
        } else {
                h_errno = HOST_NOT_FOUND;
                return NS_NOTFOUND;
        }
}

struct netent *
getnetbyaddr(uint32_t net, int net_type)
{
        int              rv;
        struct netent   *retval;

        static const ns_dtab dtab[] = {
                NS_FILES_CB(_files_getnetbyaddr, NULL)
                { NSSRC_DNS, _dns_getnetbyaddr, NULL }, /* force -DHESIOD */
                NS_NIS_CB(_yp_getnetbyaddr, NULL)
                NS_NULL_CB
        };

        retval = NULL;
        h_errno = NETDB_INTERNAL;
        rv = nsdispatch(NULL, dtab, NSDB_NETWORKS, "getnetbyaddr",
            __nsdefaultsrc, &retval, net, net_type);
        if (rv == NS_SUCCESS) {
                h_errno = NETDB_SUCCESS;
                return retval;
        }
        return NULL;
}

/*ARGSUSED*/
static int
_files_getnetbyname(void *cbrv, void *cbdata, va_list ap)
{
        struct netent   **retval = va_arg(ap, struct netent **);
        const char       *name   = va_arg(ap, const char *);

        struct netent    *np;
        char            **cp;

        setnetent(_net_stayopen);
        while ((np = getnetent()) != NULL) {
                if (strcasecmp(np->n_name, name) == 0)
                        break;
                for (cp = np->n_aliases; *cp != 0; cp++)
                        if (strcasecmp(*cp, name) == 0)
                                goto found;
        }
found:
        if (!_net_stayopen)
                endnetent();

        if (np != NULL) {
                *retval = np;
                return NS_SUCCESS;
        } else {
                h_errno = HOST_NOT_FOUND;
                return NS_NOTFOUND;
        }
}

/*ARGSUSED*/
static int
_dns_getnetbyname(void *cbrv, void *cbdata, va_list ap)
{
        struct netent   **retval = va_arg(ap, struct netent **);
        const char       *name   = va_arg(ap, const char *);

        int              anslen;
        querybuf        *buf;
        char             qbuf[MAXDNAME];
        struct netent   *np;
        res_state        res;

        strlcpy(&qbuf[0], name, sizeof(qbuf));
        buf = malloc(sizeof(*buf));
        if (buf == NULL) {
                h_errno = NETDB_INTERNAL;
                return NS_NOTFOUND;
        }
        res = __res_get_state();
        if (res == NULL) {
                free(buf);
                return NS_NOTFOUND;
        }
        anslen = res_nsearch(res, qbuf, C_IN, T_PTR, buf->buf,
            (int)sizeof(buf->buf));
        if (anslen < 0) {
                free(buf);
#ifdef DEBUG
                if (res->options & RES_DEBUG)
                        printf("res_search failed\n");
#endif
                __res_put_state(res);
                return NS_NOTFOUND;
        }
        np = getnetanswer(res, buf, anslen, BYNAME);
        __res_put_state(res);
        free(buf);

        if (np != NULL) {
                *retval = np;
                return NS_SUCCESS;
        } else {
                h_errno = HOST_NOT_FOUND;
                return NS_NOTFOUND;
        }
}

struct netent *
getnetbyname(const char *name)
{
        int              rv;
        struct netent   *retval;

        static const ns_dtab dtab[] = {
                NS_FILES_CB(_files_getnetbyname, NULL)
                { NSSRC_DNS, _dns_getnetbyname, NULL }, /* force -DHESIOD */
                NS_NIS_CB(_yp_getnetbyname, NULL)
                NS_NULL_CB
        };

        _DIAGASSERT(name != NULL);

        retval = NULL;
        h_errno = NETDB_INTERNAL;
        rv = nsdispatch(NULL, dtab, NSDB_NETWORKS, "getnetbyname",
            __nsdefaultsrc, &retval, name);
        if (rv == NS_SUCCESS) {
                h_errno = NETDB_SUCCESS;
                return retval;
        }
        return NULL;
}

#ifdef YP
/*ARGSUSED*/
static int
_yp_getnetbyaddr(void *cbrv, void *cb_data, va_list ap)
{
        struct netent   **retval = va_arg(ap, struct netent **);
        uint32_t          net    = va_arg(ap, uint32_t);
        int               type   = va_arg(ap, int);

        struct netent   *np;
        char             qbuf[MAXDNAME];
        unsigned int     netbr[4];
        uint32_t         net2;
        int              r;

        if (type != AF_INET)
                return NS_UNAVAIL;

        if (!__ypdomain) {
                if (_yp_check(&__ypdomain) == 0)
                        return NS_UNAVAIL;
        }
        np = NULL;
        if (__ypcurrent)
                free(__ypcurrent);
        __ypcurrent = NULL;
        for (r = 4, net2 = net; net2; net2 >>= 8)
                netbr[--r] = (unsigned int)(net2 & 0xff);
        switch (r) {
        default:
                return NS_UNAVAIL;
        case 3:         /* Class A */
                snprintf(qbuf, sizeof(qbuf), "%u", netbr[3]);
                break;
        case 2:         /* Class B */
                snprintf(qbuf, sizeof(qbuf), "%u.%u", netbr[2], netbr[3]);
                break;
        case 1:         /* Class C */
                snprintf(qbuf, sizeof(qbuf), "%u.%u.%u", netbr[1], netbr[2],
                    netbr[3]);
                break;
        case 0:         /* Class D - E */
                snprintf(qbuf, sizeof(qbuf), "%u.%u.%u.%u", netbr[0], netbr[1],
                    netbr[2], netbr[3]);
                break;
        }
        r = yp_match(__ypdomain, "networks.byaddr", qbuf, (int)strlen(qbuf),
            &__ypcurrent, &__ypcurrentlen);
        if (r == 0)
                np = _ypnetent(__ypcurrent);

        if (np != NULL) {
                *retval = np;
                return NS_SUCCESS;
        } else {
                h_errno = HOST_NOT_FOUND;
                return NS_NOTFOUND;
        }
}

/*ARGSUSED*/
static int
_yp_getnetbyname(void *cbrv, void *cbdata, va_list ap)
{
        struct netent   **retval = va_arg(ap, struct netent **);
        const char       *name   = va_arg(ap, const char *);

        struct netent   *np;
        int              r;

        if (!__ypdomain) {
                if (_yp_check(&__ypdomain) == 0)
                        return NS_UNAVAIL;
        }
        np = NULL;
        if (__ypcurrent)
                free(__ypcurrent);
        __ypcurrent = NULL;
        r = yp_match(__ypdomain, "networks.byname", name, (int)strlen(name),
            &__ypcurrent, &__ypcurrentlen);
        if (r == 0)
                np = _ypnetent(__ypcurrent);

        if (np != NULL) {
                *retval = np;
                return NS_SUCCESS;
        } else {
                h_errno = HOST_NOT_FOUND;
                return NS_NOTFOUND;
        }
}

static struct netent *
_ypnetent(char *line)
{
        char *cp, *p, **q;

        _DIAGASSERT(line != NULL);

        net_entry.n_name = line;
        cp = strpbrk(line, " \t");
        if (cp == NULL)
                return NULL;
        *cp++ = '\0';
        while (*cp == ' ' || *cp == '\t')
                cp++;
        p = strpbrk(cp, " \t");
        if (p != NULL)
                *p++ = '\0';
        net_entry.n_net = inet_network(cp);
#if (defined(__sparc__) && defined(_LP64)) ||           \
    defined(__alpha__) ||                               \
    (defined(__i386__) && defined(_LP64)) ||            \
    (defined(__sh__) && defined(_LP64))
        net_entry.__n_pad0 = 0;
#endif
        net_entry.n_addrtype = AF_INET;
        q = net_entry.n_aliases = net_aliases;
        if (p != NULL)  {
                cp = p;
                while (cp && *cp) {
                        if (*cp == ' ' || *cp == '\t') {
                                cp++;
                                continue;
                        }
                        if (q < &net_aliases[MAXALIASES - 1])
                                *q++ = cp;
                        cp = strpbrk(cp, " \t");
                        if (cp != NULL)
                                *cp++ = '\0';
                }
        }
        *q = NULL;

        return &net_entry;
}
#endif