minix/lib/ip/gethnmadr.c
2010-01-26 10:59:01 +00:00

329 lines
7.6 KiB
C

/*
* Copyright (c) 1985, 1988 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement: ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)gethostnamadr.c 6.41 (Berkeley) 6/1/90";
#endif /* LIBC_SCCS and not lint */
#ifdef _MINIX
#include <sys/types.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <net/hton.h>
#include <net/gen/nameser.h>
#include <net/gen/netdb.h>
#include <net/gen/in.h>
#include <net/gen/inet.h>
#include <net/gen/resolv.h>
#include <net/gen/socket.h>
#else
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <ctype.h>
#include <netdb.h>
#include <stdio.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <resolv.h>
#endif /* AMOEABA */
#define MAXALIASES 35
#define MAXADDRS 35
static char *h_addr_ptrs[MAXADDRS + 1];
#ifdef _MINIX
union querybuf;
extern int dn_skipname _ARGS(( const u_char *comp_dn, const u_char *eom ));
#define getshort _getshort
static struct hostent *getanswer _ARGS(( union querybuf *answer, int anslen,
int iquery ));
#define bcmp memcmp
#define bcopy(s, d, l) memcpy(d, s, l)
#endif /* _MINIX */
static struct hostent host;
static char *host_aliases[MAXALIASES];
static char hostbuf[BUFSIZ+1];
static struct in_addr host_addr;
#ifndef _MINIX
char *strpbrk();
#endif /* !_MINIX */
#if PACKETSZ > 1024
#define MAXPACKET PACKETSZ
#else
#define MAXPACKET 1024
#endif
typedef union querybuf
{
dns_hdr_t hdr;
u_char buf[MAXPACKET];
} querybuf_t;
typedef union align {
long al;
char ac;
} align_t;
static struct hostent *
getanswer(answer, anslen, iquery)
querybuf_t *answer;
int anslen;
int iquery;
{
register dns_hdr_t *hp;
register u_char *cp;
register int n;
u_char *eom;
char *bp, **ap;
int type, class, buflen, ancount, qdcount;
int haveanswer, getclass = C_ANY;
char **hap;
eom = answer->buf + anslen;
/*
* find first satisfactory answer
*/
hp = &answer->hdr;
ancount = ntohs(hp->dh_ancount);
qdcount = ntohs(hp->dh_qdcount);
bp = hostbuf;
buflen = sizeof(hostbuf);
cp = answer->buf + sizeof(dns_hdr_t);
if (qdcount) {
if (iquery) {
if ((n = dn_expand((u_char *)answer->buf, eom,
cp, (u_char *)bp, buflen)) < 0) {
h_errno = NO_RECOVERY;
return ((struct hostent *) NULL);
}
cp += n + QFIXEDSZ;
host.h_name = bp;
n = strlen(bp) + 1;
bp += n;
buflen -= n;
} else
cp += dn_skipname(cp, eom) + QFIXEDSZ;
while (--qdcount > 0)
cp += dn_skipname(cp, eom) + QFIXEDSZ;
} else if (iquery) {
if (hp->dh_flag1 & DHF_AA)
h_errno = HOST_NOT_FOUND;
else
h_errno = TRY_AGAIN;
return ((struct hostent *) NULL);
}
ap = host_aliases;
*ap = NULL;
host.h_aliases = host_aliases;
hap = h_addr_ptrs;
*hap = NULL;
#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
host.h_addr_list = h_addr_ptrs;
#endif
haveanswer = 0;
while (--ancount >= 0 && cp < eom) {
if ((n = dn_expand((u_char *)answer->buf, eom, cp, (u_char *)bp,
buflen)) < 0)
break;
cp += n;
type = getshort(cp);
cp += sizeof(u_short);
class = getshort(cp);
cp += sizeof(u_short) + sizeof(u_long);
n = getshort(cp);
cp += sizeof(u_short);
if (type == T_CNAME) {
cp += n;
if (ap >= &host_aliases[MAXALIASES-1])
continue;
*ap++ = bp;
n = strlen(bp) + 1;
bp += n;
buflen -= n;
continue;
}
if (iquery && type == T_PTR) {
if ((n = dn_expand((u8_t *)answer->buf, eom,
cp, (u8_t *)bp, buflen)) < 0) {
cp += n;
continue;
}
cp += n;
host.h_name = bp;
return(&host);
}
if (iquery || type != T_A) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("unexpected answer type %d, size %d\n",
type, n);
#endif
cp += n;
continue;
}
if (haveanswer) {
if (n != host.h_length) {
cp += n;
continue;
}
if (class != getclass) {
cp += n;
continue;
}
} else {
host.h_length = n;
getclass = class;
host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
if (!iquery) {
host.h_name = bp;
bp += strlen(bp) + 1;
}
}
bp += (size_t)(sizeof(align_t) -
((u_long)bp % sizeof(align_t)));
if (bp + n >= &hostbuf[sizeof(hostbuf)]) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("size (%d) too big\n", n);
#endif
break;
}
bcopy(cp, *hap++ = bp, n);
bp +=n;
cp += n;
haveanswer++;
}
if (haveanswer) {
*ap = NULL;
#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
*hap = NULL;
#else
host.h_addr = h_addr_ptrs[0];
#endif
return (&host);
} else {
h_errno = TRY_AGAIN;
return ((struct hostent *) NULL);
}
}
struct hostent *
gethostbyname(name)
_CONST char *name;
{
querybuf_t buf;
register _CONST char *cp;
int n;
/*
* disallow names consisting only of digits/dots, unless
* they end in a dot.
*/
if (isdigit(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. What if someone types
* 255.255.255.255? The test below will
* succeed spuriously... ???
*/
if ((host_addr.s_addr = inet_addr(name)) == -1) {
h_errno = HOST_NOT_FOUND;
return((struct hostent *) NULL);
}
host.h_name = (char *) name;
host.h_aliases = host_aliases;
host_aliases[0] = NULL;
host.h_addrtype = AF_INET;
host.h_length = sizeof(u_long);
h_addr_ptrs[0] = (char *)&host_addr;
h_addr_ptrs[1] = (char *)0;
#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
host.h_addr_list = h_addr_ptrs;
#else
host.h_addr = h_addr_ptrs[0];
#endif
return (&host);
}
if (!isdigit(*cp) && *cp != '.')
break;
}
if ((n = res_search((char*)name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("res_search failed\n");
#endif
return ((struct hostent *) NULL);
}
return (getanswer(&buf, n, 0));
}
struct hostent *
gethostbyaddr(addr, len, type)
const char *addr;
int len, type;
{
int n;
querybuf_t buf;
register struct hostent *hp;
char qbuf[MAXDNAME];
if (type != AF_INET)
return ((struct hostent *) NULL);
(void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
((unsigned)addr[3] & 0xff),
((unsigned)addr[2] & 0xff),
((unsigned)addr[1] & 0xff),
((unsigned)addr[0] & 0xff));
n = res_query(qbuf, C_IN, T_PTR, (u8_t *)&buf, sizeof(buf));
if (n < 0) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("res_query failed\n");
#endif
return ((struct hostent *) NULL);
}
hp = getanswer(&buf, n, 1);
if (hp == NULL)
return ((struct hostent *) NULL);
hp->h_addrtype = type;
hp->h_length = len;
h_addr_ptrs[0] = (char *)&host_addr;
h_addr_ptrs[1] = (char *)0;
host_addr = *(struct in_addr *)addr;
#if BSD < 43 && !defined(h_addr) /* new-style hostent structure */
hp->h_addr = h_addr_ptrs[0];
#endif
return(hp);
}