Viewing file: 
rfc1035qa.c (5.02 KB) -rw-rw-rw-Select action/file-type:
(
+) |
(
+) |
(
+) |
Code (
+) |
Session (
+) |
(
+) |
SDB (
+) |
(
+) |
(
+) |
(
+) |
(
+) |
(
+) |
/*
** Copyright 1998 - 2004 Double Precision, Inc.
** See COPYING for distribution information.
*/
#include "rfc1035.h"
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include "rfc1035_res.h"
/* Convenient function to do forward IP lookup */
#if RFC1035_IPV6
static int rfc1035_a_ipv4(struct rfc1035_res *res,
const char *name, struct in_addr **iaptr, unsigned *iasize)
#else
int rfc1035_a(struct rfc1035_res *res,
const char *name, RFC1035_ADDR **iaptr, unsigned *iasize)
#endif
{
struct rfc1035_reply *reply;
int n, o;
char namebuf[RFC1035_MAXNAMESIZE+1];
namebuf[0]=0;
strncat(namebuf, name, RFC1035_MAXNAMESIZE);
*iasize=0;
if (rfc1035_resolve_cname(res,
RFC1035_RESOLVE_RECURSIVE, namebuf,
RFC1035_TYPE_A, RFC1035_CLASS_IN, &reply, 0) < 0 ||
reply == 0 ||
(n=rfc1035_replysearch_an( res, reply, namebuf, RFC1035_TYPE_A,
RFC1035_CLASS_IN, 0)) < 0)
{
if (reply && reply->rcode != RFC1035_RCODE_NXDOMAIN &&
reply->rcode != RFC1035_RCODE_NOERROR)
{
errno=EAGAIN;
rfc1035_replyfree(reply);
return (1); /* soft error */
}
if (reply) rfc1035_replyfree(reply);
errno=ENOENT;
return (-1); /* hard error */
}
for (o=n; o >= 0; o=rfc1035_replysearch_an(res, reply, namebuf,
RFC1035_TYPE_A, RFC1035_CLASS_IN, o+1))
++*iasize;
if ( *iasize == 0 )
{
errno=EAGAIN;
rfc1035_replyfree(reply);
return (-1);
}
if ( (*iaptr=(struct in_addr *)malloc(sizeof(**iaptr)* *iasize)) == 0)
{
rfc1035_replyfree(reply);
return (-1);
}
for (*iasize=0; n >= 0; n=rfc1035_replysearch_an(res, reply, namebuf,
RFC1035_TYPE_A, RFC1035_CLASS_IN, n+1))
{
(*iaptr)[*iasize]= reply->allrrs[n]->rr.inaddr;
++*iasize;
}
rfc1035_replyfree(reply);
return (0);
}
#if RFC1035_IPV6
/*
** The IPv6 version issues two queries - for both A and AAAA records,
** then maps any A record to IPv6.
**
** If we get back both an AAAA for the IPv4-mapped address, and the
** A record itself, ignore the dupe.
*/
static int we_have_that_ipv4(struct in6_addr in6,
const struct in_addr *ia4ptr,
unsigned ia4len)
{
char buf[INET6_ADDRSTRLEN];
const char *p;
struct in_addr in4;
unsigned i;
if (!IN6_IS_ADDR_V4MAPPED((&in6))) return (0); /* Not an IPv4 addy */
if (inet_ntop(AF_INET6, &in6, buf, sizeof(buf)) == 0)
return (0); /* WTF??? */
if ((p=strrchr(buf, ':')) != 0)
++p;
else
p=buf;
rfc1035_aton_ipv4(p, &in4);
for (i=0; i<ia4len; i++)
if (ia4ptr[i].s_addr == in4.s_addr) return (1);
return (0);
}
int rfc1035_a(struct rfc1035_res *res,
const char *name, struct in6_addr **iaptr, unsigned *iasize)
{
struct rfc1035_reply *reply;
int n, o;
char namebuf[RFC1035_MAXNAMESIZE+1];
int enotfound=0;
struct in_addr *ia4ptr;
unsigned ia4len;
unsigned k;
n=rfc1035_a_ipv4(res, name, &ia4ptr, &ia4len);
if (n > 0) return (n);
if (n < 0)
{
if (errno != ENOENT) return (n);
ia4len=0;
ia4ptr=0;
enotfound=1;
}
namebuf[0]=0;
strncat(namebuf, name, RFC1035_MAXNAMESIZE);
*iasize=ia4len;
reply=0;
/*
** Resist the temptation to stick in "ia4len > 0 &&", below. Why?
** A) We get a connection from an IPv6 address.
** B) Spam check: the IP address must resolve backwards and forwards.
** C) There are IPv4 records for the same hostname as well.
** D) This sux.
*/
if (rfc1035_resolve_cname(res,
RFC1035_RESOLVE_RECURSIVE, namebuf,
RFC1035_TYPE_AAAA, RFC1035_CLASS_IN, &reply, 0) < 0 ||
reply == 0 ||
(n=rfc1035_replysearch_an( res, reply, namebuf,
RFC1035_TYPE_AAAA,
RFC1035_CLASS_IN, 0)) < 0)
{
if (reply && reply->rcode != RFC1035_RCODE_NXDOMAIN &&
reply->rcode != RFC1035_RCODE_NOERROR &&
*iasize == 0)
/* Unfortunately this is necessary. Some swervers
** return a TEMPFAIL for AAAA queries.
*/
{
errno=EAGAIN;
rfc1035_replyfree(reply);
if (ia4len)
free(ia4ptr);
return (1); /* soft error */
}
if (reply) rfc1035_replyfree(reply);
if (enotfound)
return (-1);
enotfound=1;
reply=0;
n= -1;
}
else
{
for (o=n; o >= 0; o=rfc1035_replysearch_an(res, reply, namebuf,
RFC1035_TYPE_AAAA, RFC1035_CLASS_IN, o+1))
{
if (we_have_that_ipv4(reply->allrrs[n]->rr.in6addr,
ia4ptr, ia4len))
continue;
++*iasize;
}
}
if ( *iasize == 0 && enotfound)
{
if (ia4len)
free(ia4ptr);
errno=ENOENT;
return (-1);
}
if ( *iasize == 0 )
{
errno=EAGAIN;
rfc1035_replyfree(reply);
return (-1);
}
if ( (*iaptr=(struct in6_addr *)malloc(sizeof(**iaptr)* *iasize)) == 0)
{
rfc1035_replyfree(reply);
return (-1);
}
for (*iasize=0; n >= 0; n=rfc1035_replysearch_an(res, reply, namebuf,
RFC1035_TYPE_AAAA, RFC1035_CLASS_IN, n+1))
{
if (we_have_that_ipv4(reply->allrrs[n]->rr.in6addr,
ia4ptr, ia4len))
continue;
(*iaptr)[*iasize]= reply->allrrs[n]->rr.in6addr;
++*iasize;
}
for (k=0; k<ia4len; k++)
{
char buf[INET6_ADDRSTRLEN];
strcpy(buf, "::ffff:");
rfc1035_ntoa_ipv4( &ia4ptr[k], buf+sizeof("::ffff:")-1);
if (inet_pton( AF_INET6, buf, (*iaptr)+ *iasize) <= 0)
memset( (*iaptr)+ *iasize, 0, sizeof(*iaptr));
++*iasize;
}
if (ia4len)
free (ia4ptr);
rfc1035_replyfree(reply);
return (0);
}
#endif
