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,strlen(owner)+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__query_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   length[0]= (qu->query_dglen&0x0ff00U) >>8;
 169   length[1]= (qu->query_dglen&0x0ff);
 170
 171   ads= qu->ads;
 172   if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2)) return;
 173
 174   timevaladd(&now,TCPMS);
 175   qu->timeout= now;
 176   qu->state= query_tcpsent;
 177
 178   if (ads->tcpsend.used) {
 179     wr= 0;
 180   } else {
 181     iov[0].iov_base= length;
 182     iov[0].iov_len= 2;
 183     iov[1].iov_base= qu->query_dgram;
 184     iov[1].iov_len= qu->query_dglen;
 185     adns__sigpipe_protect(qu->ads);
 186     wr= writev(qu->ads->tcpsocket,iov,2);
 187     adns__sigpipe_unprotect(qu->ads);
 188     if (wr < 0) {
 189       if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 190             errno == ENOBUFS || errno == ENOMEM)) {
 191         adns__tcp_broken(ads,"write",strerror(errno));
 192         return;
 193       }
 194       wr= 0;
 195     }
 196   }
 197
 198   if (wr<2) {
 199     r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
 200     wr= 0;
 201   } else {
 202     wr-= 2;
 203   }
 204   if (wr<qu->query_dglen) {
 205     r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr); assert(r);
 206   }
 207 }
 208
 209 static void query_usetcp(adns_query qu, struct timeval now) {
 210   timevaladd(&now,TCPMS);
 211   qu->timeout= now;
 212   qu->state= query_tcpwait;
 213   LIST_LINK_TAIL(qu->ads->timew,qu);
 214   adns__query_tcp(qu,now);
 215   adns__tcp_tryconnect(qu->ads,now);
 216 }
 217
 218 void adns__query_send(adns_query qu, struct timeval now) {
 219   struct sockaddr_in servaddr;
 220   int serv, r;
 221   adns_state ads;
 222
 223   assert(qu->state == query_tosend);
 224   if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
 225     query_usetcp(qu,now);
 226     return;
 227   }
 228
 229   if (qu->udpretries >= UDPMAXRETRIES) {
 230     adns__query_fail(qu,adns_s_timeout);
 231     return;
 232   }
 233
 234   serv= qu->udpnextserver;
 235   memset(&servaddr,0,sizeof(servaddr));
 236
 237   ads= qu->ads;
 238   servaddr.sin_family= AF_INET;
 239   servaddr.sin_addr= ads->servers[serv].addr;
 240   servaddr.sin_port= htons(DNS_PORT);
 241
 242   r= sendto(ads->udpsocket,qu->query_dgram,qu->query_dglen,0,
 243             (const struct sockaddr*)&servaddr,sizeof(servaddr));
 244   if (r<0 && errno == EMSGSIZE) { query_usetcp(qu,now); return; }
 245   if (r<0) adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno));
 246
 247   timevaladd(&now,UDPRETRYMS);
 248   qu->timeout= now;
 249   qu->udpsent |= (1<<serv);
 250   qu->udpnextserver= (serv+1)%ads->nservers;
 251   qu->udpretries++;
 252   LIST_LINK_TAIL(ads->timew,qu);
 253 }