mdw@git.distorted.org.uk Git - adns/blob - src/transmit.c

   1 /*
   2  * transmit.c
   3  * - construct queries
   4  * - send queries
   5  */
   6 /*
   7  *  This file is
   8  *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
   9  *
  10  *  It is part of adns, which is
  11  *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
  12  *    Copyright (C) 1999-2000 Tony Finch <dot@dotat.at>
  13  *
  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 2, or (at your option)
  17  *  any later version.
  18  *
  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.
  23  *
  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,
  26  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 #include <errno.h>
  30
  31 #include <sys/types.h>
  32 #include <sys/uio.h>
  33
  34 #include "internal.h"
  35 #include "tvarith.h"
  36
  37 #define MKQUERY_START(vb) (rqp= (vb)->buf+(vb)->used)
  38 #define MKQUERY_ADDB(b) *rqp++= (b)
  39 #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
  40 #define MKQUERY_STOP(vb) ((vb)->used= rqp-(vb)->buf)
  41
  42 static adns_status mkquery_header(adns_state ads, vbuf *vb,
  43                                   int *id_r, int qdlen) {
  44   int id;
  45   byte *rqp;
  46
  47   if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+qdlen+4)) return adns_s_nomemory;
  48
  49   vb->used= 0;
  50   MKQUERY_START(vb);
  51
  52   *id_r= id= (ads->nextid++) & 0x0ffff;
  53   MKQUERY_ADDW(id);
  54   MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
  55   MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
  56   MKQUERY_ADDW(1); /* QDCOUNT=1 */
  57   MKQUERY_ADDW(0); /* ANCOUNT=0 */
  58   MKQUERY_ADDW(0); /* NSCOUNT=0 */
  59   MKQUERY_ADDW(0); /* ARCOUNT=0 */
  60
  61   MKQUERY_STOP(vb);
  62
  63   return adns_s_ok;
  64 }
  65
  66 static adns_status mkquery_footer(vbuf *vb, adns_rrtype type) {
  67   byte *rqp;
  68
  69   MKQUERY_START(vb);
  70   MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
  71   MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */
  72   MKQUERY_STOP(vb);
  73   assert(vb->used <= vb->avail);
  74
  75   return adns_s_ok;
  76 }
  77
  78 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
  79                           const char *owner, int ol,
  80                           const typeinfo *typei, adns_queryflags flags) {
  81   int ll, c, nbytes;
  82   byte label[255], *rqp;
  83   const char *p, *pe;
  84   adns_status st;
  85
  86   st= mkquery_header(ads,vb,id_r,ol+2); if (st) return st;
  87
  88   MKQUERY_START(vb);
  89
  90   p= owner; pe= owner+ol;
  91   nbytes= 0;
  92   while (p!=pe) {
  93     ll= 0;
  94     while (p!=pe && (c= *p++)!='.') {
  95       if (c=='\\') {
  96         if (!(flags & adns_qf_quoteok_query)) return adns_s_querydomaininvalid;
  97         if (ctype_digit(p[0])) {
  98           if (ctype_digit(p[1]) && ctype_digit(p[2])) {
  99             c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
 100             if (c >= 256) return adns_s_querydomaininvalid;
 101           } else {
 102             return adns_s_querydomaininvalid;
 103           }
 104         } else if (!(c= *p++)) {
 105           return adns_s_querydomaininvalid;
 106         }
 107       }
 108       if (!(flags & adns_qf_quoteok_query)) {
 109         if (c == '-') {
 110           if (!ll) return adns_s_querydomaininvalid;
 111         } else if (!ctype_alpha(c) && !ctype_digit(c)) {
 112           return adns_s_querydomaininvalid;
 113         }
 114       }
 115       if (ll == sizeof(label)) return adns_s_querydomaininvalid;
 116       label[ll++]= c;
 117     }
 118     if (!ll) return adns_s_querydomaininvalid;
 119     if (ll > DNS_MAXLABEL) return adns_s_querydomaintoolong;
 120     nbytes+= ll+1;
 121     if (nbytes >= DNS_MAXDOMAIN) return adns_s_querydomaintoolong;
 122     MKQUERY_ADDB(ll);
 123     memcpy(rqp,label,ll); rqp+= ll;
 124   }
 125   MKQUERY_ADDB(0);
 126
 127   MKQUERY_STOP(vb);
 128
 129   st= mkquery_footer(vb,typei->type);
 130
 131   return adns_s_ok;
 132 }
 133
 134 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
 135                                   const byte *qd_dgram, int qd_dglen,
 136                                   int qd_begin,
 137                                   adns_rrtype type, adns_queryflags flags) {
 138   byte *rqp;
 139   findlabel_state fls;
 140   int lablen, labstart;
 141   adns_status st;
 142
 143   st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st;
 144
 145   MKQUERY_START(vb);
 146
 147   adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0);
 148   for (;;) {
 149     st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st);
 150     if (!lablen) break;
 151     assert(lablen<255);
 152     MKQUERY_ADDB(lablen);
 153     memcpy(rqp,qd_dgram+labstart,lablen);
 154     rqp+= lablen;
 155   }
 156   MKQUERY_ADDB(0);
 157
 158   MKQUERY_STOP(vb);
 159
 160   st= mkquery_footer(vb,type);
 161
 162   return adns_s_ok;
 163 }
 164
 165 void adns__querysend_tcp(adns_query qu, struct timeval now) {
 166   byte length[2];
 167   struct iovec iov[2];
 168   int wr, r;
 169   adns_state ads;
 170
 171   if (qu->ads->tcpstate != server_ok) return;
 172
 173   assert(qu->state == query_tcpw);
 174
 175   length[0]= (qu->query_dglen&0x0ff00U) >>8;
 176   length[1]= (qu->query_dglen&0x0ff);
 177
 178   ads= qu->ads;
 179   if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2))
 180     return;
 181
 182   qu->retries++;
 183
 184   /* Reset idle timeout. */
 185   ads->tcptimeout.tv_sec= ads->tcptimeout.tv_usec= 0;
 186
 187   if (ads->tcpsend.used) {
 188     wr= 0;
 189   } else {
 190     iov[0].iov_base= length;
 191     iov[0].iov_len= 2;
 192     iov[1].iov_base= qu->query_dgram;
 193     iov[1].iov_len= qu->query_dglen;
 194     adns__sigpipe_protect(qu->ads);
 195     wr= writev(qu->ads->tcpsocket,iov,2);
 196     adns__sigpipe_unprotect(qu->ads);
 197     if (wr < 0) {
 198       if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 199             errno == ENOBUFS || errno == ENOMEM)) {
 200         adns__tcp_broken(ads,"write",strerror(errno));
 201         return;
 202       }
 203       wr= 0;
 204     }
 205   }
 206
 207   if (wr<2) {
 208     r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
 209     wr= 0;
 210   } else {
 211     wr-= 2;
 212   }
 213   if (wr<qu->query_dglen) {
 214     r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr);
 215     assert(r);
 216   }
 217 }
 218
 219 static void query_usetcp(adns_query qu, struct timeval now) {
 220   qu->state= query_tcpw;
 221   qu->timeout= now;
 222   timevaladd(&qu->timeout,TCPWAITMS);
 223   LIST_LINK_TAIL(qu->ads->tcpw,qu);
 224   adns__querysend_tcp(qu,now);
 225   adns__tcp_tryconnect(qu->ads,now);
 226 }
 227
 228 void adns__query_send(adns_query qu, struct timeval now) {
 229   struct sockaddr_in servaddr;
 230   int serv, r;
 231   adns_state ads;
 232
 233   assert(qu->state == query_tosend);
 234   if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
 235     query_usetcp(qu,now);
 236     return;
 237   }
 238
 239   if (qu->retries >= UDPMAXRETRIES) {
 240     adns__query_fail(qu,adns_s_timeout);
 241     return;
 242   }
 243
 244   serv= qu->udpnextserver;
 245   memset(&servaddr,0,sizeof(servaddr));
 246
 247   ads= qu->ads;
 248   servaddr.sin_family= AF_INET;
 249   servaddr.sin_addr= ads->servers[serv].addr;
 250   servaddr.sin_port= htons(DNS_PORT);
 251
 252   r= sendto(ads->udpsocket,qu->query_dgram,qu->query_dglen,0,
 253             (const struct sockaddr*)&servaddr,sizeof(servaddr));
 254   if (r<0 && errno == EMSGSIZE) {
 255     qu->retries= 0;
 256     query_usetcp(qu,now);
 257     return;
 258   }
 259   if (r<0 && errno != EAGAIN)
 260     adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno));
 261
 262   qu->timeout= now;
 263   timevaladd(&qu->timeout,UDPRETRYMS);
 264   qu->udpsent |= (1<<serv);
 265   qu->udpnextserver= (serv+1)%ads->nservers;
 266   qu->retries++;
 267   LIST_LINK_TAIL(ads->udpw,qu);
 268 }