7 * This file is part of adns, which is
8 * Copyright (C) 1997-2000,2003,2006,2014-2016,2020 Ian Jackson
9 * Copyright (C) 2014 Mark Wooding
10 * Copyright (C) 1999-2000,2003,2006 Tony Finch
11 * Copyright (C) 1991 Massachusetts Institute of Technology
12 * (See the file INSTALL for full details.)
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 3, or (at your option)
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software Foundation.
30 #include <sys/types.h>
36 #define MKQUERY_START(vb) (rqp= (vb)->buf+(vb)->used)
37 #define MKQUERY_ADDB(b) *rqp++= (b)
38 #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
39 #define MKQUERY_STOP(vb) ((vb)->used= rqp-(vb)->buf)
41 static adns_status mkquery_header(adns_state ads, vbuf *vb,
42 int *id_r, int qdlen) {
46 if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+qdlen+4)) return adns_s_nomemory;
51 *id_r= id= (ads->nextid++) & 0x0ffff;
53 MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
54 MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
55 MKQUERY_ADDW(1); /* QDCOUNT=1 */
56 MKQUERY_ADDW(0); /* ANCOUNT=0 */
57 MKQUERY_ADDW(0); /* NSCOUNT=0 */
58 MKQUERY_ADDW(0); /* ARCOUNT=0 */
65 static adns_status mkquery_footer(vbuf *vb, adns_rrtype type) {
69 MKQUERY_ADDW(type & adns_rrt_typemask); /* QTYPE */
70 MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */
72 assert(vb->used <= vb->avail);
77 static adns_status qdparselabel(adns_state ads,
78 const char **p_io, const char *pe,
79 char label_r[], int *ll_io,
80 adns_queryflags flags) {
87 while (p!=pe && (c= *p++)!='.') {
89 if (!(flags & adns_qf_quoteok_query)) return adns_s_querydomaininvalid;
90 if (p==pe) return adns_s_querydomaininvalid;
91 if (ctype_digit(p[0])) {
92 if (p+1==pe || p+2==pe) return adns_s_querydomaininvalid;
93 if (ctype_digit(p[1]) && ctype_digit(p[2])) {
97 if (c >= 256) return adns_s_querydomaininvalid;
99 return adns_s_querydomaininvalid;
101 } else if (!(c= *p++)) {
102 return adns_s_querydomaininvalid;
105 if (ll == *ll_io) return adns_s_querydomaininvalid;
114 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
115 const char *owner, int ol,
116 const typeinfo *typei, adns_rrtype type,
117 adns_queryflags flags) {
124 st= mkquery_header(ads,vb,id_r,ol+2); if (st) return st;
128 p= owner; pe= owner+ol;
132 st= qdparselabel(ads, &p,pe, label, &ll, flags);
134 if (!ll) return adns_s_querydomaininvalid;
135 if (ll > DNS_MAXLABEL) return adns_s_querydomaintoolong;
137 if (nbytes >= DNS_MAXDOMAIN) return adns_s_querydomaintoolong;
139 memcpy(rqp,label,ll); rqp+= ll;
145 st= mkquery_footer(vb,type);
150 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
151 const byte *qd_dgram, int qd_dglen,
153 adns_rrtype type, adns_queryflags flags) {
156 int lablen, labstart;
159 st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st;
163 adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0);
165 st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st);
168 MKQUERY_ADDB(lablen);
169 memcpy(rqp,qd_dgram+labstart,lablen);
176 st= mkquery_footer(vb,type);
181 void adns__querysend_tcp(adns_query qu, struct timeval now) {
187 if (qu->ads->tcpstate != server_ok) return;
189 assert(qu->state == query_tcpw);
191 length[0]= (qu->query_dglen&0x0ff00U) >>8;
192 length[1]= (qu->query_dglen&0x0ff);
195 if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2))
200 /* Reset idle timeout. */
201 ads->tcptimeout.tv_sec= ads->tcptimeout.tv_usec= 0;
203 if (ads->tcpsend.used) {
206 iov[0].iov_base= length;
208 iov[1].iov_base= qu->query_dgram;
209 iov[1].iov_len= qu->query_dglen;
210 adns__sigpipe_protect(qu->ads);
211 wr= writev(qu->ads->tcpsocket,iov,2);
212 adns__sigpipe_unprotect(qu->ads);
214 if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
215 errno == ENOBUFS || errno == ENOMEM)) {
216 adns__tcp_broken(ads,"write",strerror(errno));
224 r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
229 if (wr<qu->query_dglen) {
230 r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr);
235 static void query_usetcp(adns_query qu, struct timeval now) {
236 qu->state= query_tcpw;
237 adns__timeout_set(qu,now,TCPWAITMS);
238 LIST_LINK_TAIL(qu->ads->tcpw,qu);
239 adns__querysend_tcp(qu,now);
240 adns__tcp_tryconnect(qu->ads,now);
243 struct udpsocket *adns__udpsocket_by_af(adns_state ads, int af) {
245 for (i=0; i<ads->nudpsockets; i++)
246 if (ads->udpsockets[i].af == af) return &ads->udpsockets[i];
250 void adns__query_send(adns_query qu, struct timeval now) {
253 struct udpsocket *udp;
256 assert(qu->state == query_tosend);
257 if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
258 query_usetcp(qu,now);
262 if (qu->retries >= UDPMAXRETRIES) {
263 adns__query_fail(qu,adns_s_timeout);
268 serv= qu->udpnextserver;
269 addr= &ads->servers[serv];
270 udp= adns__udpsocket_by_af(ads, addr->addr.sa.sa_family);
273 r= sendto(udp->fd,qu->query_dgram,qu->query_dglen,0,
274 &addr->addr.sa,addr->len);
275 if (r<0 && errno == EMSGSIZE) {
277 query_usetcp(qu,now);
280 if (r<0 && errno != EAGAIN)
281 adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno));
283 adns__timeout_set(qu, now, UDPRETRYMS);
284 qu->udpsent |= (1<<serv);
285 qu->udpnextserver= (serv+1)%ads->nservers;
287 LIST_LINK_TAIL(ads->udpw,qu);