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/*
** Copyright 1998 - 2000 Double Precision, Inc.
** See COPYING for distribution information.
*/
#include "config.h"
#include <stdio.h>
#include "soxwrap/soxwrap.h"
#include "rfc1035.h"
#include <errno.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <string.h>
struct querybuf {
char qbuf[512];
unsigned qbuflen;
} ;
static void putqbuf(const char *p, unsigned l, void *q)
{
struct querybuf *qp=(struct querybuf *)q;
if (qp->qbuflen < sizeof(qp->qbuf) &&
sizeof(qp->qbuf) - qp->qbuflen >= l)
memcpy(qp->qbuf+qp->qbuflen, p, l);
qp->qbuflen += l;
}
struct rfc1035_reply *rfc1035_resolve_multiple(
struct rfc1035_res *res,
int opcode,
const struct rfc1035_query *queries,
unsigned nqueries)
{
struct querybuf qbuf;
int udpfd;
int attempt;
const RFC1035_ADDR *ns;
unsigned nscount;
unsigned current_timeout, timeout_backoff;
unsigned nbackoff, backoff_num;
int af;
static const char fakereply[]={0, 0, 0, RFC1035_RCODE_SERVFAIL,
0, 0,
0, 0,
0, 0,
0, 0};
nscount=res->rfc1035_nnameservers;
ns=res->nameservers;
if (res->rfc1035_good_ns >= nscount)
res->rfc1035_good_ns=0;
qbuf.qbuflen=0;
if ( rfc1035_mkquery(res,
opcode, queries, nqueries, &putqbuf, &qbuf))
{
errno=EINVAL;
return (0);
}
/* Prepare the UDP socket */
if ((udpfd=rfc1035_open_udp(&af)) < 0) return (0);
/* Keep trying until we get an answer from a nameserver */
current_timeout=res->rfc1035_timeout_initial;
nbackoff=res->rfc1035_timeout_backoff;
if (!current_timeout) current_timeout=RFC1035_DEFAULT_INITIAL_TIMEOUT;
if (!nbackoff) nbackoff=RFC1035_DEFAULT_MAXIMUM_BACKOFF;
timeout_backoff=current_timeout;
for (backoff_num=0; backoff_num < nbackoff; backoff_num++,
current_timeout *= timeout_backoff)
for ( attempt=0; attempt < nscount; ++attempt)
{
int nbytes;
char *reply;
struct rfc1035_reply *rfcreply=0;
const RFC1035_ADDR *sin=&ns[(res->rfc1035_good_ns+attempt) % nscount];
int sin_len=sizeof(*sin);
int dotcp=0, isaxfr=0;
unsigned i;
for (i=0; i<nqueries; i++)
if (queries[i].qtype == RFC1035_TYPE_AXFR)
{
dotcp=1;
isaxfr=1;
break;
}
if (isaxfr && nqueries > 1)
return (rfc1035_replyparse(fakereply,
sizeof(fakereply)));
if (!dotcp)
{
/* Send the query via UDP */
RFC1035_NETADDR addrbuf;
const struct sockaddr *addrptr;
int addrptrlen;
if (rfc1035_mkaddress(af, &addrbuf,
sin, htons(53),
&addrptr, &addrptrlen))
continue;
if ((reply=rfc1035_query_udp(res, udpfd, addrptr,
addrptrlen, qbuf.qbuf, qbuf.qbuflen, &nbytes,
current_timeout)) == 0)
continue;
res->rfc1035_good_ns= (res->rfc1035_good_ns + attempt) %
nscount;
/* Parse the reply */
rfcreply=rfc1035_replyparse(reply, nbytes);
if (!rfcreply)
{
free(reply);
if (errno == ENOMEM) break;
continue;
/* Bad response from the server, try the next one. */
}
rfcreply->mallocedbuf=reply;
/*
** If the reply came back with the truncated bit set,
** retry the query via TCP.
*/
if (rfcreply->tc)
{
dotcp=1;
rfc1035_replyfree(rfcreply);
}
}
if (dotcp)
{
int tcpfd;
struct rfc1035_reply *firstreply=0, *lastreply=0;
if ((tcpfd=rfc1035_open_tcp(res, sin)) < 0)
continue; /*
** Can't connect via TCP,
** try the next server.
*/
reply=rfc1035_query_tcp(res, tcpfd, qbuf.qbuf,
qbuf.qbuflen, &nbytes, current_timeout);
if (!reply)
{
sox_close(tcpfd);
continue;
}
res->rfc1035_good_ns= (res->rfc1035_good_ns
+ attempt) % nscount;
rfcreply=rfc1035_replyparse(reply, nbytes);
if (!rfcreply)
{
free(reply);
sox_close(tcpfd);
continue;
}
rfcreply->mallocedbuf=reply;
firstreply=lastreply=rfcreply;
while (isaxfr && rfcreply->rcode == 0)
{
if ((reply=rfc1035_recv_tcp(res,
tcpfd, &nbytes, current_timeout))==0)
break;
rfcreply=rfc1035_replyparse(reply, nbytes);
if (!rfcreply)
{
free(reply);
rfc1035_replyfree(firstreply);
firstreply=0;
break;
}
rfcreply->mallocedbuf=reply;
lastreply->next=rfcreply;
lastreply=rfcreply;
if ( rfcreply->ancount &&
rfcreply->anptr[0].rrtype ==
RFC1035_TYPE_SOA)
break;
}
sox_close(tcpfd);
if (!firstreply)
return (0);
rfcreply=firstreply;
}
memcpy(&rfcreply->server_addr, sin, sin_len);
sox_close(udpfd);
return (rfcreply);
}
/*
** Return a fake server failure reply, when we couldn't contact
** any name server.
*/
sox_close(udpfd);
return (rfc1035_replyparse(fakereply, sizeof(fakereply)));
}
struct rfc1035_reply *rfc1035_resolve(
struct rfc1035_res *res,
int opcode,
const char *name,
unsigned qtype,
unsigned qclass)
{
struct rfc1035_query q;
q.name=name;
q.qtype=qtype;
q.qclass=qclass;
return (rfc1035_resolve_multiple(res, opcode, &q, 1));
}
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