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
  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)
  40
  41 static adns_status mkquery_header(adns_state ads, vbuf *vb, int *id_r, int qdlen) {
  42   int id;
  43   byte *rqp;
  44
  45   if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+qdlen+4)) return adns_s_nomemory;
  46
  47   vb->used= 0;
  48   MKQUERY_START(vb);
  49
  50   *id_r= id= (ads->nextid++) & 0x0ffff;
  51   MKQUERY_ADDW(id);
  52   MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
  53   MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
  54   MKQUERY_ADDW(1); /* QDCOUNT=1 */
  55   MKQUERY_ADDW(0); /* ANCOUNT=0 */
  56   MKQUERY_ADDW(0); /* NSCOUNT=0 */
  57   MKQUERY_ADDW(0); /* ARCOUNT=0 */
  58
  59   MKQUERY_STOP(vb);
  60
  61   return adns_s_ok;
  62 }
  63
  64 static adns_status mkquery_footer(vbuf *vb, adns_rrtype type) {
  65   byte *rqp;
  66
  67   MKQUERY_START(vb);
  68   MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
  69   MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */
  70   MKQUERY_STOP(vb);
  71   assert(vb->used <= vb->avail);
  72
  73   return adns_s_ok;
  74 }
  75
  76 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
  77                           const char *owner, int ol,
  78                           const typeinfo *typei, adns_queryflags flags) {
  79   int ll, c, nlabs;
  80   byte label[255], *rqp;
  81   const char *p, *pe;
  82   adns_status st;
  83
  84   st= mkquery_header(ads,vb,id_r,ol+2); if (st) return st;
  85
  86   MKQUERY_START(vb);
  87
  88   p= owner; pe= owner+ol;
  89   nlabs= 0;
  90   while (p!=pe) {
  91     ll= 0;
  92     while (p!=pe && (c= *p++)!='.') {
  93       if (c=='\\') {
  94         if (!(flags & adns_qf_quoteok_query)) return adns_s_querydomaininvalid;
  95         if (ctype_digit(p[0])) {
  96           if (ctype_digit(p[1]) && ctype_digit(p[2])) {
  97             c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*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 == sizeof(label)) return adns_s_querydomaininvalid;
 114       label[ll++]= c;
 115     }
 116     if (!ll) return adns_s_querydomaininvalid;
 117     if (nlabs++ > 63) return adns_s_querydomaintoolong;
 118     MKQUERY_ADDB(ll);
 119     memcpy(rqp,label,ll); rqp+= ll;
 120   }
 121   MKQUERY_ADDB(0);
 122
 123   MKQUERY_STOP(vb);
 124
 125   st= mkquery_footer(vb,typei->type);
 126
 127   return adns_s_ok;
 128 }
 129
 130 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
 131                                   const byte *qd_dgram, int qd_dglen, int qd_begin,
 132                                   adns_rrtype type, adns_queryflags flags) {
 133   byte *rqp;
 134   findlabel_state fls;
 135   int lablen, labstart;
 136   adns_status st;
 137
 138   st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st;
 139
 140   MKQUERY_START(vb);
 141
 142   adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0);
 143   for (;;) {
 144     st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st);
 145     if (!lablen) break;
 146     assert(lablen<255);
 147     MKQUERY_ADDB(lablen);
 148     memcpy(rqp,qd_dgram+labstart,lablen);
 149     rqp+= lablen;
 150   }
 151   MKQUERY_ADDB(0);
 152
 153   MKQUERY_STOP(vb);
 154
 155   st= mkquery_footer(vb,type);
 156
 157   return adns_s_ok;
 158 }
 159
 160 void adns__querysend_tcp(adns_query qu, struct timeval now) {
 161   byte length[2];
 162   struct iovec iov[2];
 163   int wr, r;
 164   adns_state ads;
 165
 166   if (qu->ads->tcpstate != server_ok) return;
 167
 168   assert(qu->state == query_tcpw);
 169
 170   length[0]= (qu->query_dglen&0x0ff00U) >>8;
 171   length[1]= (qu->query_dglen&0x0ff);
 172
 173   ads= qu->ads;
 174   if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2)) return;
 175
 176   qu->retries++;
 177
 178   /* Reset idle timeout. */
 179   ads->tcptimeout.tv_sec= ads->tcptimeout.tv_usec= 0;
 180
 181   if (ads->tcpsend.used) {
 182     wr= 0;
 183   } else {
 184     iov[0].iov_base= length;
 185     iov[0].iov_len= 2;
 186     iov[1].iov_base= qu->query_dgram;
 187     iov[1].iov_len= qu->query_dglen;
 188     adns__sigpipe_protect(qu->ads);
 189     wr= writev(qu->ads->tcpsocket,iov,2);
 190     adns__sigpipe_unprotect(qu->ads);
 191     if (wr < 0) {
 192       if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 193             errno == ENOBUFS || errno == ENOMEM)) {
 194         adns__tcp_broken(ads,"write",strerror(errno));
 195         return;
 196       }
 197       wr= 0;
 198     }
 199   }
 200
 201   if (wr<2) {
 202     r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
 203     wr= 0;
 204   } else {
 205     wr-= 2;
 206   }
 207   if (wr<qu->query_dglen) {
 208     r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr); assert(r);
 209   }
 210 }
 211
 212 static void query_usetcp(adns_query qu, struct timeval now) {
 213   qu->state= query_tcpw;
 214   qu->timeout= now;
 215   timevaladd(&qu->timeout,TCPWAITMS);
 216   LIST_LINK_TAIL(qu->ads->tcpw,qu);
 217   adns__querysend_tcp(qu,now);
 218   adns__tcp_tryconnect(qu->ads,now);
 219 }
 220
 221 void adns__query_send(adns_query qu, struct timeval now) {
 222   struct sockaddr_in servaddr;
 223   int serv, r;
 224   adns_state ads;
 225
 226   assert(qu->state == query_tosend);
 227   if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
 228     query_usetcp(qu,now);
 229     return;
 230   }
 231
 232   if (qu->retries >= UDPMAXRETRIES) {
 233     adns__query_fail(qu,adns_s_timeout);
 234     return;
 235   }
 236
 237   serv= qu->udpnextserver;
 238   memset(&servaddr,0,sizeof(servaddr));
 239
 240   ads= qu->ads;
 241   servaddr.sin_family= AF_INET;
 242   servaddr.sin_addr= ads->servers[serv].addr;
 243   servaddr.sin_port= htons(DNS_PORT);
 244
 245   r= sendto(ads->udpsocket,qu->query_dgram,qu->query_dglen,0,
 246             (const struct sockaddr*)&servaddr,sizeof(servaddr));
 247   if (r<0 && errno == EMSGSIZE) { qu->retries= 0; query_usetcp(qu,now); return; }
 248   if (r<0) adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno));
 249
 250   qu->timeout= now;
 251   timevaladd(&qu->timeout,UDPRETRYMS);
 252   qu->udpsent |= (1<<serv);
 253   qu->udpnextserver= (serv+1)%ads->nservers;
 254   qu->retries++;
 255   LIST_LINK_TAIL(ads->udpw,qu);
 256 }