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) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
   9  *
  10  *  It is part of adns, which is
  11  *    Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
  12  *    Copyright (C) 1999 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, int *id_r, int qdlen) {
  43   int id;
  44   byte *rqp;
  45
  46   if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+qdlen+4)) return adns_s_nomemory;
  47
  48   vb->used= 0;
  49   MKQUERY_START(vb);
  50
  51   *id_r= id= (ads->nextid++) & 0x0ffff;
  52   MKQUERY_ADDW(id);
  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 */
  59
  60   MKQUERY_STOP(vb);
  61
  62   return adns_s_ok;
  63 }
  64
  65 static adns_status mkquery_footer(vbuf *vb, adns_rrtype type) {
  66   byte *rqp;
  67
  68   MKQUERY_START(vb);
  69   MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
  70   MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */
  71   MKQUERY_STOP(vb);
  72   assert(vb->used <= vb->avail);
  73
  74   return adns_s_ok;
  75 }
  76
  77 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
  78                           const char *owner, int ol,
  79                           const typeinfo *typei, adns_queryflags flags) {
  80   int ll, c, nlabs;
  81   byte label[255], *rqp;
  82   const char *p, *pe;
  83   adns_status st;
  84
  85   st= mkquery_header(ads,vb,id_r,ol+2); if (st) return st;
  86
  87   MKQUERY_START(vb);
  88
  89   p= owner; pe= owner+ol;
  90   nlabs= 0;
  91   while (p!=pe) {
  92     ll= 0;
  93     while (p!=pe && (c= *p++)!='.') {
  94       if (c=='\\') {
  95         if (!(flags & adns_qf_quoteok_query)) return adns_s_querydomaininvalid;
  96         if (ctype_digit(p[0])) {
  97           if (ctype_digit(p[1]) && ctype_digit(p[2])) {
  98             c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
  99             if (c >= 256) return adns_s_querydomaininvalid;
 100           } else {
 101             return adns_s_querydomaininvalid;
 102           }
 103         } else if (!(c= *p++)) {
 104           return adns_s_querydomaininvalid;
 105         }
 106       }
 107       if (!(flags & adns_qf_quoteok_query)) {
 108         if (c == '-') {
 109           if (!ll) return adns_s_querydomaininvalid;
 110         } else if (!ctype_alpha(c) && !ctype_digit(c)) {
 111           return adns_s_querydomaininvalid;
 112         }
 113       }
 114       if (ll == sizeof(label)) return adns_s_querydomaininvalid;
 115       label[ll++]= c;
 116     }
 117     if (!ll) return adns_s_querydomaininvalid;
 118     if (nlabs++ > 63) return adns_s_querydomaintoolong;
 119     MKQUERY_ADDB(ll);
 120     memcpy(rqp,label,ll); rqp+= ll;
 121   }
 122   MKQUERY_ADDB(0);
 123
 124   MKQUERY_STOP(vb);
 125
 126   st= mkquery_footer(vb,typei->type);
 127
 128   return adns_s_ok;
 129 }
 130
 131 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
 132                                   const byte *qd_dgram, int qd_dglen, int qd_begin,
 133                                   adns_rrtype type, adns_queryflags flags) {
 134   byte *rqp;
 135   findlabel_state fls;
 136   int lablen, labstart;
 137   adns_status st;
 138
 139   st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st;
 140
 141   MKQUERY_START(vb);
 142
 143   adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0);
 144   for (;;) {
 145     st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st);
 146     if (!lablen) break;
 147     assert(lablen<255);
 148     MKQUERY_ADDB(lablen);
 149     memcpy(rqp,qd_dgram+labstart,lablen);
 150     rqp+= lablen;
 151   }
 152   MKQUERY_ADDB(0);
 153
 154   MKQUERY_STOP(vb);
 155
 156   st= mkquery_footer(vb,type);
 157
 158   return adns_s_ok;
 159 }
 160
 161 void adns__querysend_tcp(adns_query qu, struct timeval now) {
 162   byte length[2];
 163   struct iovec iov[2];
 164   int wr, r;
 165   adns_state ads;
 166
 167   if (qu->ads->tcpstate != server_ok) return;
 168
 169   assert(qu->state == query_tcpw);
 170
 171   length[0]= (qu->query_dglen&0x0ff00U) >>8;
 172   length[1]= (qu->query_dglen&0x0ff);
 173
 174   ads= qu->ads;
 175   if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2)) return;
 176
 177   qu->retries++;
 178
 179   /* Reset idle timeout. */
 180   ads->tcptimeout.tv_sec= ads->tcptimeout.tv_usec= 0;
 181
 182   if (ads->tcpsend.used) {
 183     wr= 0;
 184   } else {
 185     iov[0].iov_base= length;
 186     iov[0].iov_len= 2;
 187     iov[1].iov_base= qu->query_dgram;
 188     iov[1].iov_len= qu->query_dglen;
 189     adns__sigpipe_protect(qu->ads);
 190     wr= writev(qu->ads->tcpsocket,iov,2);
 191     adns__sigpipe_unprotect(qu->ads);
 192     if (wr < 0) {
 193       if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 194             errno == ENOBUFS || errno == ENOMEM)) {
 195         adns__tcp_broken(ads,"write",strerror(errno));
 196         return;
 197       }
 198       wr= 0;
 199     }
 200   }
 201
 202   if (wr<2) {
 203     r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
 204     wr= 0;
 205   } else {
 206     wr-= 2;
 207   }
 208   if (wr<qu->query_dglen) {
 209     r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr); assert(r);
 210   }
 211 }
 212
 213 static void query_usetcp(adns_query qu, struct timeval now) {
 214   qu->state= query_tcpw;
 215   qu->timeout= now;
 216   timevaladd(&qu->timeout,TCPWAITMS);
 217   LIST_LINK_TAIL(qu->ads->tcpw,qu);
 218   adns__querysend_tcp(qu,now);
 219   adns__tcp_tryconnect(qu->ads,now);
 220 }
 221
 222 void adns__query_send(adns_query qu, struct timeval now) {
 223   struct sockaddr_in servaddr;
 224   int serv, r;
 225   adns_state ads;
 226
 227   assert(qu->state == query_tosend);
 228   if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
 229     query_usetcp(qu,now);
 230     return;
 231   }
 232
 233   if (qu->retries >= UDPMAXRETRIES) {
 234     adns__query_fail(qu,adns_s_timeout);
 235     return;
 236   }
 237
 238   serv= qu->udpnextserver;
 239   memset(&servaddr,0,sizeof(servaddr));
 240
 241   ads= qu->ads;
 242   servaddr.sin_family= AF_INET;
 243   servaddr.sin_addr= ads->servers[serv].addr;
 244   servaddr.sin_port= htons(DNS_PORT);
 245
 246   r= sendto(ads->udpsocket,qu->query_dgram,qu->query_dglen,0,
 247             (const struct sockaddr*)&servaddr,sizeof(servaddr));
 248   if (r<0 && errno == EMSGSIZE) { qu->retries= 0; query_usetcp(qu,now); return; }
 249   if (r<0) adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno));
 250
 251   qu->timeout= now;
 252   timevaladd(&qu->timeout,UDPRETRYMS);
 253   qu->udpsent |= (1<<serv);
 254   qu->udpnextserver= (serv+1)%ads->nservers;
 255   qu->retries++;
 256   LIST_LINK_TAIL(ads->udpw,qu);
 257 }