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__qdpl_normal(adns_state ads,
  79                               const char **p_io, const char *pe, int labelnum,
  80                               char label_r[], int *ll_io,
  81                               adns_queryflags flags,
  82                               const typeinfo *typei) {
  83   int ll, c;
  84   const char *p;
  85
  86   ll= 0;
  87   p= *p_io;
  88
  89   while (p!=pe && (c= *p++)!='.') {
  90     if (c=='\\') {
  91       if (!(flags & adns_qf_quoteok_query)) return adns_s_querydomaininvalid;
  92       if (ctype_digit(p[0])) {
  93         if (p+1==pe || p+2==pe) return adns_s_querydomaininvalid;
  94         if (ctype_digit(p[1]) && ctype_digit(p[2])) {
  95           c= (*p++ - '0')*100;
  96           c += (*p++ - '0')*10;
  97           c += (*p++ - '0');
  98           if (c >= 256) return adns_s_querydomaininvalid;
  99         } else {
 100           return adns_s_querydomaininvalid;
 101         }
 102       } else if (!(c= *p++)) {
 103         return adns_s_querydomaininvalid;
 104       }
 105     }
 106     if (!(flags & adns_qf_quoteok_query)) {
 107       if (c == '-') {
 108         if (!ll) return adns_s_querydomaininvalid;
 109       } else if (!ctype_alpha(c) && !ctype_digit(c)) {
 110         return adns_s_querydomaininvalid;
 111       }
 112     }
 113     if (ll == *ll_io) return adns_s_querydomaininvalid;
 114     label_r[ll++]= c;
 115   }
 116
 117   *p_io= p;
 118   *ll_io= ll;
 119   return adns_s_ok;
 120 }
 121
 122 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
 123                           const char *owner, int ol,
 124                           const typeinfo *typei, adns_rrtype type,
 125                           adns_queryflags flags) {
 126   int labelnum, ll, nbytes;
 127   byte label[255];
 128   byte *rqp;
 129   const char *p, *pe;
 130   adns_status st;
 131
 132   st= mkquery_header(ads,vb,id_r,ol+2); if (st) return st;
 133
 134   MKQUERY_START(vb);
 135
 136   p= owner; pe= owner+ol;
 137   nbytes= 0;
 138   labelnum= 0;
 139   while (p!=pe) {
 140     ll= sizeof(label);
 141     st= typei->qdparselabel(ads, &p,pe, labelnum++, label, &ll, flags, typei);
 142     if (st) return st;
 143     if (!ll) return adns_s_querydomaininvalid;
 144     if (ll > DNS_MAXLABEL) return adns_s_querydomaintoolong;
 145     nbytes+= ll+1;
 146     if (nbytes >= DNS_MAXDOMAIN) return adns_s_querydomaintoolong;
 147     MKQUERY_ADDB(ll);
 148     memcpy(rqp,label,ll); rqp+= ll;
 149   }
 150   MKQUERY_ADDB(0);
 151
 152   MKQUERY_STOP(vb);
 153
 154   st= mkquery_footer(vb,type);
 155
 156   return adns_s_ok;
 157 }
 158
 159 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
 160                                   const byte *qd_dgram, int qd_dglen,
 161                                   int qd_begin,
 162                                   adns_rrtype type, adns_queryflags flags) {
 163   byte *rqp;
 164   findlabel_state fls;
 165   int lablen, labstart;
 166   adns_status st;
 167
 168   st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st;
 169
 170   MKQUERY_START(vb);
 171
 172   adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0);
 173   for (;;) {
 174     st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st);
 175     if (!lablen) break;
 176     assert(lablen<255);
 177     MKQUERY_ADDB(lablen);
 178     memcpy(rqp,qd_dgram+labstart,lablen);
 179     rqp+= lablen;
 180   }
 181   MKQUERY_ADDB(0);
 182
 183   MKQUERY_STOP(vb);
 184
 185   st= mkquery_footer(vb,type);
 186
 187   return adns_s_ok;
 188 }
 189
 190 void adns__querysend_tcp(adns_query qu, struct timeval now) {
 191   byte length[2];
 192   struct iovec iov[2];
 193   int wr, r;
 194   adns_state ads;
 195
 196   if (qu->ads->tcpstate != server_ok) return;
 197
 198   assert(qu->state == query_tcpw);
 199
 200   length[0]= (qu->query_dglen&0x0ff00U) >>8;
 201   length[1]= (qu->query_dglen&0x0ff);
 202
 203   ads= qu->ads;
 204   if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2))
 205     return;
 206
 207   qu->retries++;
 208
 209   /* Reset idle timeout. */
 210   ads->tcptimeout.tv_sec= ads->tcptimeout.tv_usec= 0;
 211
 212   if (ads->tcpsend.used) {
 213     wr= 0;
 214   } else {
 215     iov[0].iov_base= length;
 216     iov[0].iov_len= 2;
 217     iov[1].iov_base= qu->query_dgram;
 218     iov[1].iov_len= qu->query_dglen;
 219     adns__sigpipe_protect(qu->ads);
 220     wr= writev(qu->ads->tcpsocket,iov,2);
 221     adns__sigpipe_unprotect(qu->ads);
 222     if (wr < 0) {
 223       if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 224             errno == ENOBUFS || errno == ENOMEM)) {
 225         adns__tcp_broken(ads,"write",strerror(errno));
 226         return;
 227       }
 228       wr= 0;
 229     }
 230   }
 231
 232   if (wr<2) {
 233     r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
 234     wr= 0;
 235   } else {
 236     wr-= 2;
 237   }
 238   if (wr<qu->query_dglen) {
 239     r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr);
 240     assert(r);
 241   }
 242 }
 243
 244 static void query_usetcp(adns_query qu, struct timeval now) {
 245   qu->state= query_tcpw;
 246   qu->timeout= now;
 247   timevaladd(&qu->timeout,TCPWAITMS);
 248   LIST_LINK_TAIL(qu->ads->tcpw,qu);
 249   adns__querysend_tcp(qu,now);
 250   adns__tcp_tryconnect(qu->ads,now);
 251 }
 252
 253 void adns__query_send(adns_query qu, struct timeval now) {
 254   struct sockaddr_in servaddr;
 255   int serv, r;
 256   adns_state ads;
 257
 258   assert(qu->state == query_tosend);
 259   if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
 260     query_usetcp(qu,now);
 261     return;
 262   }
 263
 264   if (qu->retries >= UDPMAXRETRIES) {
 265     adns__query_fail(qu,adns_s_timeout);
 266     return;
 267   }
 268
 269   serv= qu->udpnextserver;
 270   memset(&servaddr,0,sizeof(servaddr));
 271
 272   ads= qu->ads;
 273   servaddr.sin_family= AF_INET;
 274   servaddr.sin_addr= ads->servers[serv].addr;
 275   servaddr.sin_port= htons(DNS_PORT);
 276
 277   r= sendto(ads->udpsocket,qu->query_dgram,qu->query_dglen,0,
 278             (const struct sockaddr*)&servaddr,sizeof(servaddr));
 279   if (r<0 && errno == EMSGSIZE) {
 280     qu->retries= 0;
 281     query_usetcp(qu,now);
 282     return;
 283   }
 284   if (r<0 && errno != EAGAIN)
 285     adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno));
 286
 287   qu->timeout= now;
 288   timevaladd(&qu->timeout,UDPRETRYMS);
 289   qu->udpsent |= (1<<serv);
 290   qu->udpnextserver= (serv+1)%ads->nservers;
 291   qu->retries++;
 292   LIST_LINK_TAIL(ads->udpw,qu);
 293 }