7 * This file is part of adns, which is Copyright Ian Jackson
8 * and contributors (see the file INSTALL for full details).
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 3, or (at your option)
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software Foundation.
26 #include <sys/types.h>
32 #define MKQUERY_START(vb) (rqp= (vb)->buf+(vb)->used)
33 #define MKQUERY_ADDB(b) *rqp++= (b)
34 #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
35 #define MKQUERY_STOP(vb) ((vb)->used= rqp-(vb)->buf)
37 static adns_status mkquery_header(adns_state ads, vbuf *vb,
38 int *id_r, int qdlen) {
42 if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+qdlen+4)) return adns_s_nomemory;
47 *id_r= id= (ads->nextid++) & 0x0ffff;
49 MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
50 MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
51 MKQUERY_ADDW(1); /* QDCOUNT=1 */
52 MKQUERY_ADDW(0); /* ANCOUNT=0 */
53 MKQUERY_ADDW(0); /* NSCOUNT=0 */
54 MKQUERY_ADDW(0); /* ARCOUNT=0 */
61 static adns_status mkquery_footer(vbuf *vb, adns_rrtype type) {
65 MKQUERY_ADDW(type & adns_rrt_typemask); /* QTYPE */
66 MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */
68 assert(vb->used <= vb->avail);
73 static adns_status qdparselabel(adns_state ads,
74 const char **p_io, const char *pe,
75 char label_r[], int *ll_io,
76 adns_queryflags flags) {
83 while (p!=pe && (c= *p++)!='.') {
85 if (!(flags & adns_qf_quoteok_query)) return adns_s_querydomaininvalid;
86 if (p==pe) return adns_s_querydomaininvalid;
87 if (ctype_digit(p[0])) {
88 if (p+1==pe || p+2==pe) return adns_s_querydomaininvalid;
89 if (ctype_digit(p[1]) && ctype_digit(p[2])) {
93 if (c >= 256) return adns_s_querydomaininvalid;
95 return adns_s_querydomaininvalid;
97 } else if (!(c= *p++)) {
98 return adns_s_querydomaininvalid;
101 if (ll == *ll_io) return adns_s_querydomaininvalid;
110 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
111 const char *owner, int ol,
112 const typeinfo *typei, adns_rrtype type,
113 adns_queryflags flags) {
120 st= mkquery_header(ads,vb,id_r,ol+2); if (st) return st;
124 p= owner; pe= owner+ol;
128 st= qdparselabel(ads, &p,pe, label, &ll, flags);
130 if (!ll) return adns_s_querydomaininvalid;
131 if (ll > DNS_MAXLABEL) return adns_s_querydomaintoolong;
133 if (nbytes >= DNS_MAXDOMAIN) return adns_s_querydomaintoolong;
135 memcpy(rqp,label,ll); rqp+= ll;
141 st= mkquery_footer(vb,type);
146 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
147 const byte *qd_dgram, int qd_dglen,
149 adns_rrtype type, adns_queryflags flags) {
152 int lablen, labstart;
155 st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st;
159 adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0);
161 st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st);
164 MKQUERY_ADDB(lablen);
165 memcpy(rqp,qd_dgram+labstart,lablen);
172 st= mkquery_footer(vb,type);
177 void adns__querysend_tcp(adns_query qu, struct timeval now) {
183 if (qu->ads->tcpstate != server_ok) return;
185 assert(qu->state == query_tcpw);
187 length[0]= (qu->query_dglen&0x0ff00U) >>8;
188 length[1]= (qu->query_dglen&0x0ff);
191 if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2))
196 /* Reset idle timeout. */
197 ads->tcptimeout.tv_sec= ads->tcptimeout.tv_usec= 0;
199 if (ads->tcpsend.used) {
202 iov[0].iov_base= length;
204 iov[1].iov_base= qu->query_dgram;
205 iov[1].iov_len= qu->query_dglen;
206 adns__sigpipe_protect(qu->ads);
207 wr= writev(qu->ads->tcpsocket,iov,2);
208 adns__sigpipe_unprotect(qu->ads);
210 if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
211 errno == ENOBUFS || errno == ENOMEM)) {
212 adns__tcp_broken(ads,"write",strerror(errno));
220 r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
225 if (wr<qu->query_dglen) {
226 r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr);
231 static void query_usetcp(adns_query qu, struct timeval now) {
232 qu->state= query_tcpw;
233 adns__timeout_set(qu,now,TCPWAITMS);
234 LIST_LINK_TAIL(qu->ads->tcpw,qu);
235 adns__querysend_tcp(qu,now);
236 adns__tcp_tryconnect(qu->ads,now);
239 struct udpsocket *adns__udpsocket_by_af(adns_state ads, int af) {
241 for (i=0; i<ads->nudpsockets; i++)
242 if (ads->udpsockets[i].af == af) return &ads->udpsockets[i];
246 void adns__query_send(adns_query qu, struct timeval now) {
249 struct udpsocket *udp;
252 assert(qu->state == query_tosend);
253 if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
254 query_usetcp(qu,now);
258 if (qu->retries >= UDPMAXRETRIES) {
259 adns__query_fail(qu,adns_s_timeout);
264 serv= qu->udpnextserver;
265 addr= &ads->servers[serv];
266 udp= adns__udpsocket_by_af(ads, addr->addr.sa.sa_family);
269 r= sendto(udp->fd,qu->query_dgram,qu->query_dglen,0,
270 &addr->addr.sa,addr->len);
271 if (r<0 && errno == EMSGSIZE) {
273 query_usetcp(qu,now);
276 if (r<0 && errno != EAGAIN)
277 adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno));
279 adns__timeout_set(qu, now, UDPRETRYMS);
280 qu->udpsent |= (1<<serv);
281 qu->udpnextserver= (serv+1)%ads->nservers;
283 LIST_LINK_TAIL(ads->udpw,qu);