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/*
* transmit.c
* - construct queries
* - send queries
*/
/*
* This file is
* Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
*
* It is part of adns, which is
* Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
* Copyright (C) 1999 Tony Finch <dot@dotat.at>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <errno.h>
#include <sys/types.h>
#include <sys/uio.h>
#include "internal.h"
#include "tvarith.h"
#define MKQUERY_START(vb) (rqp= (vb)->buf+(vb)->used)
#define MKQUERY_ADDB(b) *rqp++= (b)
#define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
#define MKQUERY_STOP(vb) ((vb)->used= rqp-(vb)->buf)
static adns_status mkquery_header(adns_state ads, vbuf *vb, int *id_r, int qdlen) {
int id;
byte *rqp;
if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+qdlen+4)) return adns_s_nomemory;
vb->used= 0;
MKQUERY_START(vb);
*id_r= id= (ads->nextid++) & 0x0ffff;
MKQUERY_ADDW(id);
MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
MKQUERY_ADDW(1); /* QDCOUNT=1 */
MKQUERY_ADDW(0); /* ANCOUNT=0 */
MKQUERY_ADDW(0); /* NSCOUNT=0 */
MKQUERY_ADDW(0); /* ARCOUNT=0 */
MKQUERY_STOP(vb);
return adns_s_ok;
}
static adns_status mkquery_footer(vbuf *vb, adns_rrtype type) {
byte *rqp;
MKQUERY_START(vb);
MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */
MKQUERY_STOP(vb);
assert(vb->used <= vb->avail);
return adns_s_ok;
}
adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
const char *owner, int ol,
const typeinfo *typei, adns_queryflags flags) {
int ll, c, nlabs;
byte label[255], *rqp;
const char *p, *pe;
adns_status st;
st= mkquery_header(ads,vb,id_r,ol+2); if (st) return st;
MKQUERY_START(vb);
p= owner; pe= owner+ol;
nlabs= 0;
while (p!=pe) {
ll= 0;
while (p!=pe && (c= *p++)!='.') {
if (c=='\\') {
if (!(flags & adns_qf_quoteok_query)) return adns_s_querydomaininvalid;
if (ctype_digit(p[0])) {
if (ctype_digit(p[1]) && ctype_digit(p[2])) {
c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
if (c >= 256) return adns_s_querydomaininvalid;
} else {
return adns_s_querydomaininvalid;
}
} else if (!(c= *p++)) {
return adns_s_querydomaininvalid;
}
}
if (!(flags & adns_qf_quoteok_query)) {
if (c == '-') {
if (!ll) return adns_s_querydomaininvalid;
} else if (!ctype_alpha(c) && !ctype_digit(c)) {
return adns_s_querydomaininvalid;
}
}
if (ll == sizeof(label)) return adns_s_querydomaininvalid;
label[ll++]= c;
}
if (!ll) return adns_s_querydomaininvalid;
if (nlabs++ > 63) return adns_s_querydomaintoolong;
MKQUERY_ADDB(ll);
memcpy(rqp,label,ll); rqp+= ll;
}
MKQUERY_ADDB(0);
MKQUERY_STOP(vb);
st= mkquery_footer(vb,typei->type);
return adns_s_ok;
}
adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
const byte *qd_dgram, int qd_dglen, int qd_begin,
adns_rrtype type, adns_queryflags flags) {
byte *rqp;
findlabel_state fls;
int lablen, labstart;
adns_status st;
st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st;
MKQUERY_START(vb);
adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0);
for (;;) {
st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st);
if (!lablen) break;
assert(lablen<255);
MKQUERY_ADDB(lablen);
memcpy(rqp,qd_dgram+labstart,lablen);
rqp+= lablen;
}
MKQUERY_ADDB(0);
MKQUERY_STOP(vb);
st= mkquery_footer(vb,type);
return adns_s_ok;
}
void adns__querysend_tcp(adns_query qu, struct timeval now) {
byte length[2];
struct iovec iov[2];
int wr, r;
adns_state ads;
if (qu->ads->tcpstate != server_ok) return;
assert(qu->state == query_tcpw);
length[0]= (qu->query_dglen&0x0ff00U) >>8;
length[1]= (qu->query_dglen&0x0ff);
ads= qu->ads;
if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2)) return;
qu->retries++;
/* Reset idle timeout. */
ads->tcptimeout.tv_sec= ads->tcptimeout.tv_usec= 0;
if (ads->tcpsend.used) {
wr= 0;
} else {
iov[0].iov_base= length;
iov[0].iov_len= 2;
iov[1].iov_base= qu->query_dgram;
iov[1].iov_len= qu->query_dglen;
adns__sigpipe_protect(qu->ads);
wr= writev(qu->ads->tcpsocket,iov,2);
adns__sigpipe_unprotect(qu->ads);
if (wr < 0) {
if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
errno == ENOBUFS || errno == ENOMEM)) {
adns__tcp_broken(ads,"write",strerror(errno));
return;
}
wr= 0;
}
}
if (wr<2) {
r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
wr= 0;
} else {
wr-= 2;
}
if (wr<qu->query_dglen) {
r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr); assert(r);
}
}
static void query_usetcp(adns_query qu, struct timeval now) {
qu->state= query_tcpw;
qu->timeout= now;
timevaladd(&qu->timeout,TCPWAITMS);
LIST_LINK_TAIL(qu->ads->tcpw,qu);
adns__querysend_tcp(qu,now);
adns__tcp_tryconnect(qu->ads,now);
}
void adns__query_send(adns_query qu, struct timeval now) {
struct sockaddr_in servaddr;
int serv, r;
adns_state ads;
assert(qu->state == query_tosend);
if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
query_usetcp(qu,now);
return;
}
if (qu->retries >= UDPMAXRETRIES) {
adns__query_fail(qu,adns_s_timeout);
return;
}
serv= qu->udpnextserver;
memset(&servaddr,0,sizeof(servaddr));
ads= qu->ads;
servaddr.sin_family= AF_INET;
servaddr.sin_addr= ads->servers[serv].addr;
servaddr.sin_port= htons(DNS_PORT);
r= sendto(ads->udpsocket,qu->query_dgram,qu->query_dglen,0,
(const struct sockaddr*)&servaddr,sizeof(servaddr));
if (r<0 && errno == EMSGSIZE) { qu->retries= 0; query_usetcp(qu,now); return; }
if (r<0) adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno));
qu->timeout= now;
timevaladd(&qu->timeout,UDPRETRYMS);
qu->udpsent |= (1<<serv);
qu->udpnextserver= (serv+1)%ads->nservers;
qu->retries++;
LIST_LINK_TAIL(ads->udpw,qu);
}
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