diff options
Diffstat (limited to 'lib/libc/net/gethostbydns.c')
| -rw-r--r-- | lib/libc/net/gethostbydns.c | 773 |
1 files changed, 773 insertions, 0 deletions
diff --git a/lib/libc/net/gethostbydns.c b/lib/libc/net/gethostbydns.c new file mode 100644 index 0000000..bd1f181 --- /dev/null +++ b/lib/libc/net/gethostbydns.c @@ -0,0 +1,773 @@ +/* + * ++Copyright++ 1985, 1988, 1993 + * - + * Copyright (c) 1985, 1988, 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. 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. + * - + * Portions Copyright (c) 1993 by Digital Equipment Corporation. + * + * 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, and that + * the name of Digital Equipment Corporation not be used in advertising or + * publicity pertaining to distribution of the document or software without + * specific, written prior permission. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL + * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT + * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL + * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR + * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS + * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS + * SOFTWARE. + * - + * --Copyright-- + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93"; +static char fromrcsid[] = "From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $"; +static char rcsid[] = "$FreeBSD$"; +#endif /* LIBC_SCCS and not lint */ + +#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 <stdio.h> +#include <unistd.h> +#include <string.h> +#include <netdb.h> +#include <resolv.h> +#include <ctype.h> +#include <errno.h> +#include <syslog.h> + +#include "res_config.h" + +#define SPRINTF(x) ((size_t)sprintf x) + +#define MAXALIASES 35 +#define MAXADDRS 35 + +static const char AskedForGot[] = + "gethostby*.gethostanswer: asked for \"%s\", got \"%s\""; + +static char *h_addr_ptrs[MAXADDRS + 1]; + +static struct hostent host; +static char *host_aliases[MAXALIASES]; +static char hostbuf[8*1024]; +static u_char host_addr[16]; /* IPv4 or IPv6 */ + +#ifdef RESOLVSORT +static void addrsort __P((char **, int)); +#endif + +#if PACKETSZ > 1024 +#define MAXPACKET PACKETSZ +#else +#define MAXPACKET 1024 +#endif + +typedef union { + HEADER hdr; + u_char buf[MAXPACKET]; +} querybuf; + +typedef union { + int32_t al; + char ac; +} align; + +extern int h_errno; +int _dns_ttl_; + +#ifdef DEBUG +static void +dprintf(msg, num) + char *msg; + int num; +{ + if (_res.options & RES_DEBUG) { + int save = errno; + + printf(msg, num); + errno = save; + } +} +#else +# define dprintf(msg, num) /*nada*/ +#endif + +#define BOUNDED_INCR(x) \ + do { \ + cp += x; \ + if (cp > eom) { \ + h_errno = NO_RECOVERY; \ + return (NULL); \ + } \ + } while (0) + +#define BOUNDS_CHECK(ptr, count) \ + do { \ + if ((ptr) + (count) > eom) { \ + h_errno = NO_RECOVERY; \ + return (NULL); \ + } \ + } while (0) + +static struct hostent * +gethostanswer(answer, anslen, qname, qtype) + const querybuf *answer; + int anslen; + const char *qname; + int qtype; +{ + register const HEADER *hp; + register const u_char *cp; + register int n; + const u_char *eom, *erdata; + char *bp, **ap, **hap; + int type, class, buflen, ancount, qdcount; + int haveanswer, had_error; + int toobig = 0; + char tbuf[MAXDNAME]; + const char *tname; + int (*name_ok) __P((const char *)); + + tname = qname; + host.h_name = NULL; + eom = answer->buf + anslen; + switch (qtype) { + case T_A: + case T_AAAA: + name_ok = res_hnok; + break; + case T_PTR: + name_ok = res_dnok; + break; + default: + h_errno = NO_RECOVERY; + return (NULL); /* XXX should be abort(); */ + } + /* + * find first satisfactory answer + */ + hp = &answer->hdr; + ancount = ntohs(hp->ancount); + qdcount = ntohs(hp->qdcount); + bp = hostbuf; + buflen = sizeof hostbuf; + cp = answer->buf; + BOUNDED_INCR(HFIXEDSZ); + if (qdcount != 1) { + h_errno = NO_RECOVERY; + return (NULL); + } + n = dn_expand(answer->buf, eom, cp, bp, buflen); + if ((n < 0) || !(*name_ok)(bp)) { + h_errno = NO_RECOVERY; + return (NULL); + } + BOUNDED_INCR(n + QFIXEDSZ); + if (qtype == T_A || qtype == T_AAAA) { + /* res_send() has already verified that the query name is the + * same as the one we sent; this just gets the expanded name + * (i.e., with the succeeding search-domain tacked on). + */ + n = strlen(bp) + 1; /* for the \0 */ + if (n >= MAXHOSTNAMELEN) { + h_errno = NO_RECOVERY; + return (NULL); + } + host.h_name = bp; + bp += n; + buflen -= n; + /* The qname can be abbreviated, but h_name is now absolute. */ + qname = host.h_name; + } + ap = host_aliases; + *ap = NULL; + host.h_aliases = host_aliases; + hap = h_addr_ptrs; + *hap = NULL; + host.h_addr_list = h_addr_ptrs; + haveanswer = 0; + had_error = 0; + _dns_ttl_ = -1; + while (ancount-- > 0 && cp < eom && !had_error) { + n = dn_expand(answer->buf, eom, cp, bp, buflen); + if ((n < 0) || !(*name_ok)(bp)) { + had_error++; + continue; + } + cp += n; /* name */ + BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ); + type = _getshort(cp); + cp += INT16SZ; /* type */ + class = _getshort(cp); + cp += INT16SZ; /* class */ + if (qtype == T_A && type == T_A) + _dns_ttl_ = _getlong(cp); + cp += INT32SZ; /* TTL */ + n = _getshort(cp); + cp += INT16SZ; /* len */ + BOUNDS_CHECK(cp, n); + erdata = cp + n; + if (class != C_IN) { + /* XXX - debug? syslog? */ + cp += n; + continue; /* XXX - had_error++ ? */ + } + if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) { + if (ap >= &host_aliases[MAXALIASES-1]) + continue; + n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); + if ((n < 0) || !(*name_ok)(tbuf)) { + had_error++; + continue; + } + cp += n; + if (cp != erdata) { + h_errno = NO_RECOVERY; + return (NULL); + } + /* Store alias. */ + *ap++ = bp; + n = strlen(bp) + 1; /* for the \0 */ + if (n >= MAXHOSTNAMELEN) { + had_error++; + continue; + } + bp += n; + buflen -= n; + /* Get canonical name. */ + n = strlen(tbuf) + 1; /* for the \0 */ + if (n > buflen || n >= MAXHOSTNAMELEN) { + had_error++; + continue; + } + strcpy(bp, tbuf); + host.h_name = bp; + bp += n; + buflen -= n; + continue; + } + if (qtype == T_PTR && type == T_CNAME) { + n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); + if (n < 0 || !res_dnok(tbuf)) { + had_error++; + continue; + } + cp += n; + if (cp != erdata) { + h_errno = NO_RECOVERY; + return (NULL); + } + /* Get canonical name. */ + n = strlen(tbuf) + 1; /* for the \0 */ + if (n > buflen || n >= MAXHOSTNAMELEN) { + had_error++; + continue; + } + strcpy(bp, tbuf); + tname = bp; + bp += n; + buflen -= n; + continue; + } + if (type != qtype) { + syslog(LOG_NOTICE|LOG_AUTH, + "gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"", + qname, p_class(C_IN), p_type(qtype), + p_type(type)); + cp += n; + continue; /* XXX - had_error++ ? */ + } + switch (type) { + case T_PTR: + if (strcasecmp(tname, bp) != 0) { + syslog(LOG_NOTICE|LOG_AUTH, + AskedForGot, qname, bp); + cp += n; + continue; /* XXX - had_error++ ? */ + } + n = dn_expand(answer->buf, eom, cp, bp, buflen); + if ((n < 0) || !res_hnok(bp)) { + had_error++; + break; + } +#if MULTI_PTRS_ARE_ALIASES + cp += n; + if (cp != erdata) { + h_errno = NO_RECOVERY; + return (NULL); + } + if (!haveanswer) + host.h_name = bp; + else if (ap < &host_aliases[MAXALIASES-1]) + *ap++ = bp; + else + n = -1; + if (n != -1) { + n = strlen(bp) + 1; /* for the \0 */ + if (n >= MAXHOSTNAMELEN) { + had_error++; + break; + } + bp += n; + buflen -= n; + } + break; +#else + host.h_name = bp; + if (_res.options & RES_USE_INET6) { + n = strlen(bp) + 1; /* for the \0 */ + if (n >= MAXHOSTNAMELEN) { + had_error++; + break; + } + bp += n; + buflen -= n; + _map_v4v6_hostent(&host, &bp, &buflen); + } + h_errno = NETDB_SUCCESS; + return (&host); +#endif + case T_A: + case T_AAAA: + if (strcasecmp(host.h_name, bp) != 0) { + syslog(LOG_NOTICE|LOG_AUTH, + AskedForGot, host.h_name, bp); + cp += n; + continue; /* XXX - had_error++ ? */ + } + if (n != host.h_length) { + cp += n; + continue; + } + if (!haveanswer) { + register int nn; + + host.h_name = bp; + nn = strlen(bp) + 1; /* for the \0 */ + bp += nn; + buflen -= nn; + } + + bp += sizeof(align) - ((u_long)bp % sizeof(align)); + + if (bp + n >= &hostbuf[sizeof hostbuf]) { + dprintf("size (%d) too big\n", n); + had_error++; + continue; + } + if (hap >= &h_addr_ptrs[MAXADDRS-1]) { + if (!toobig++) + dprintf("Too many addresses (%d)\n", + MAXADDRS); + cp += n; + continue; + } + bcopy(cp, *hap++ = bp, n); + bp += n; + buflen -= n; + cp += n; + if (cp != erdata) { + h_errno = NO_RECOVERY; + return (NULL); + } + break; + default: + dprintf("Impossible condition (type=%d)\n", type); + h_errno = NO_RECOVERY; + return (NULL); + /* BIND has abort() here, too risky on bad data */ + } + if (!had_error) + haveanswer++; + } + if (haveanswer) { + *ap = NULL; + *hap = NULL; +# if defined(RESOLVSORT) + /* + * Note: we sort even if host can take only one address + * in its return structures - should give it the "best" + * address in that case, not some random one + */ + if (_res.nsort && haveanswer > 1 && qtype == T_A) + addrsort(h_addr_ptrs, haveanswer); +# endif /*RESOLVSORT*/ + if (!host.h_name) { + n = strlen(qname) + 1; /* for the \0 */ + if (n > buflen || n >= MAXHOSTNAMELEN) + goto no_recovery; + strcpy(bp, qname); + host.h_name = bp; + bp += n; + buflen -= n; + } + if (_res.options & RES_USE_INET6) + _map_v4v6_hostent(&host, &bp, &buflen); + h_errno = NETDB_SUCCESS; + return (&host); + } + no_recovery: + h_errno = NO_RECOVERY; + return (NULL); +} + +struct hostent * +__dns_getanswer(answer, anslen, qname, qtype) + const char *answer; + int anslen; + const char *qname; + int qtype; +{ + switch(qtype) { + case T_AAAA: + host.h_addrtype = AF_INET6; + host.h_length = IN6ADDRSZ; + break; + case T_A: + default: + host.h_addrtype = AF_INET; + host.h_length = INADDRSZ; + break; + } + + return(gethostanswer((const querybuf *)answer, anslen, qname, qtype)); +} + +struct hostent * +_gethostbydnsname(name, af) + const char *name; + int af; +{ + querybuf buf; + register const char *cp; + char *bp; + int n, size, type, len; + + if ((_res.options & RES_INIT) == 0 && res_init() == -1) { + h_errno = NETDB_INTERNAL; + return (NULL); + } + + switch (af) { + case AF_INET: + size = INADDRSZ; + type = T_A; + break; + case AF_INET6: + size = IN6ADDRSZ; + type = T_AAAA; + break; + default: + h_errno = NETDB_INTERNAL; + errno = EAFNOSUPPORT; + return (NULL); + } + + host.h_addrtype = af; + host.h_length = size; + + /* + * if there aren't any dots, it could be a user-level alias. + * this is also done in res_query() since we are not the only + * function that looks up host names. + */ + if (!strchr(name, '.') && (cp = __hostalias(name))) + name = cp; + + /* + * disallow names consisting only of digits/dots, unless + * they end in a dot. + */ + if (isdigit((unsigned char)name[0])) + for (cp = name;; ++cp) { + if (!*cp) { + if (*--cp == '.') + break; + /* + * All-numeric, no dot at the end. + * Fake up a hostent as if we'd actually + * done a lookup. + */ + if (inet_pton(af, name, host_addr) <= 0) { + h_errno = HOST_NOT_FOUND; + return (NULL); + } + strncpy(hostbuf, name, MAXDNAME); + hostbuf[MAXDNAME] = '\0'; + bp = hostbuf + MAXDNAME; + len = sizeof hostbuf - MAXDNAME; + host.h_name = hostbuf; + host.h_aliases = host_aliases; + host_aliases[0] = NULL; + h_addr_ptrs[0] = (char *)host_addr; + h_addr_ptrs[1] = NULL; + host.h_addr_list = h_addr_ptrs; + if (_res.options & RES_USE_INET6) + _map_v4v6_hostent(&host, &bp, &len); + h_errno = NETDB_SUCCESS; + return (&host); + } + if (!isdigit((unsigned char)*cp) && *cp != '.') + break; + } + if ((isxdigit((unsigned char)name[0]) && strchr(name, ':') != NULL) || + name[0] == ':') + for (cp = name;; ++cp) { + if (!*cp) { + if (*--cp == '.') + break; + /* + * All-IPv6-legal, no dot at the end. + * Fake up a hostent as if we'd actually + * done a lookup. + */ + if (inet_pton(af, name, host_addr) <= 0) { + h_errno = HOST_NOT_FOUND; + return (NULL); + } + strncpy(hostbuf, name, MAXDNAME); + hostbuf[MAXDNAME] = '\0'; + bp = hostbuf + MAXDNAME; + len = sizeof hostbuf - MAXDNAME; + host.h_name = hostbuf; + host.h_aliases = host_aliases; + host_aliases[0] = NULL; + h_addr_ptrs[0] = (char *)host_addr; + h_addr_ptrs[1] = NULL; + host.h_addr_list = h_addr_ptrs; + h_errno = NETDB_SUCCESS; + return (&host); + } + if (!isxdigit((unsigned char)*cp) && *cp != ':' && *cp != '.') + break; + } + + if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf))) < 0) { + dprintf("res_search failed (%d)\n", n); + return (NULL); + } + return (gethostanswer(&buf, n, name, type)); +} + +struct hostent * +_gethostbydnsaddr(addr, len, af) + const char *addr; /* XXX should have been def'd as u_char! */ + int len, af; +{ + const u_char *uaddr = (const u_char *)addr; + static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff }; + static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 }; + int n, size; + querybuf buf; + register struct hostent *hp; + char qbuf[MAXDNAME+1], *qp; +#ifdef SUNSECURITY + register struct hostent *rhp; + char **haddr; + u_long old_options; + char hname2[MAXDNAME+1]; +#endif /*SUNSECURITY*/ + + if ((_res.options & RES_INIT) == 0 && res_init() == -1) { + h_errno = NETDB_INTERNAL; + return (NULL); + } + if (af == AF_INET6 && len == IN6ADDRSZ && + (!bcmp(uaddr, mapped, sizeof mapped) || + !bcmp(uaddr, tunnelled, sizeof tunnelled))) { + /* Unmap. */ + addr += sizeof mapped; + uaddr += sizeof mapped; + af = AF_INET; + len = INADDRSZ; + } + switch (af) { + case AF_INET: + size = INADDRSZ; + break; + case AF_INET6: + size = IN6ADDRSZ; + break; + default: + errno = EAFNOSUPPORT; + h_errno = NETDB_INTERNAL; + return (NULL); + } + if (size != len) { + errno = EINVAL; + h_errno = NETDB_INTERNAL; + return (NULL); + } + switch (af) { + case AF_INET: + (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", + (uaddr[3] & 0xff), + (uaddr[2] & 0xff), + (uaddr[1] & 0xff), + (uaddr[0] & 0xff)); + break; + case AF_INET6: + qp = qbuf; + for (n = IN6ADDRSZ - 1; n >= 0; n--) { + qp += SPRINTF((qp, "%x.%x.", + uaddr[n] & 0xf, + (uaddr[n] >> 4) & 0xf)); + } + strcpy(qp, "ip6.int"); + break; + default: + abort(); + } + n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf); + if (n < 0) { + dprintf("res_query failed (%d)\n", n); + return (NULL); + } + if (!(hp = gethostanswer(&buf, n, qbuf, T_PTR))) + return (NULL); /* h_errno was set by gethostanswer() */ +#ifdef SUNSECURITY + if (af == AF_INET) { + /* + * turn off search as the name should be absolute, + * 'localhost' should be matched by defnames + */ + strncpy(hname2, hp->h_name, MAXDNAME); + hname2[MAXDNAME] = '\0'; + old_options = _res.options; + _res.options &= ~RES_DNSRCH; + _res.options |= RES_DEFNAMES; + if (!(rhp = gethostbyname(hname2))) { + syslog(LOG_NOTICE|LOG_AUTH, + "gethostbyaddr: No A record for %s (verifying [%s])", + hname2, inet_ntoa(*((struct in_addr *)addr))); + _res.options = old_options; + h_errno = HOST_NOT_FOUND; + return (NULL); + } + _res.options = old_options; + for (haddr = rhp->h_addr_list; *haddr; haddr++) + if (!memcmp(*haddr, addr, INADDRSZ)) + break; + if (!*haddr) { + syslog(LOG_NOTICE|LOG_AUTH, + "gethostbyaddr: A record of %s != PTR record [%s]", + hname2, inet_ntoa(*((struct in_addr *)addr))); + h_errno = HOST_NOT_FOUND; + return (NULL); + } + } +#endif /*SUNSECURITY*/ + hp->h_addrtype = af; + hp->h_length = len; + bcopy(addr, host_addr, len); + h_addr_ptrs[0] = (char *)host_addr; + h_addr_ptrs[1] = NULL; + if (af == AF_INET && (_res.options & RES_USE_INET6)) { + _map_v4v6_address((char*)host_addr, (char*)host_addr); + hp->h_addrtype = AF_INET6; + hp->h_length = IN6ADDRSZ; + } + h_errno = NETDB_SUCCESS; + return (hp); +} + +#ifdef RESOLVSORT +static void +addrsort(ap, num) + char **ap; + int num; +{ + int i, j; + char **p; + short aval[MAXADDRS]; + int needsort = 0; + + p = ap; + for (i = 0; i < num; i++, p++) { + for (j = 0 ; (unsigned)j < _res.nsort; j++) + if (_res.sort_list[j].addr.s_addr == + (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask)) + break; + aval[i] = j; + if (needsort == 0 && i > 0 && j < aval[i-1]) + needsort = i; + } + if (!needsort) + return; + + while (needsort < num) { + for (j = needsort - 1; j >= 0; j--) { + if (aval[j] > aval[j+1]) { + char *hp; + + i = aval[j]; + aval[j] = aval[j+1]; + aval[j+1] = i; + + hp = ap[j]; + ap[j] = ap[j+1]; + ap[j+1] = hp; + + } else + break; + } + needsort++; + } +} +#endif +void +_sethostdnsent(stayopen) + int stayopen; +{ + if ((_res.options & RES_INIT) == 0 && res_init() == -1) + return; + if (stayopen) + _res.options |= RES_STAYOPEN | RES_USEVC; +} + +void +_endhostdnsent() +{ + _res.options &= ~(RES_STAYOPEN | RES_USEVC); + res_close(); +} |
