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 part of adns, which is Copyright (C) 1997-1999 Ian Jackson
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2, or (at your option)
  12  *  any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to the Free Software Foundation,
  21  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  22  */
  23
  24 #include <errno.h>
  25 #include <string.h>
  26
  27 #include <sys/types.h>
  28 #include <sys/uio.h>
  29
  30 #include "internal.h"
  31
  32 #define MKQUERY_START(vb) (rqp= (vb)->buf+(vb)->used)
  33 #define MKQUERY_ADDB(b) *rqp++= (b)
  34 #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
  35 #define MKQUERY_STOP(vb) ((vb)->used= rqp-(vb)->buf)
  36
  37 static adns_status mkquery_header(adns_state ads, vbuf *vb, int *id_r, int qdlen) {
  38   int id;
  39   byte *rqp;
  40
  41   if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+qdlen+4)) return adns_s_nomemory;
  42
  43   vb->used= 0;
  44   MKQUERY_START(vb);
  45
  46   *id_r= id= (ads->nextid++) & 0x0ffff;
  47   MKQUERY_ADDW(id);
  48   MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
  49   MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
  50   MKQUERY_ADDW(1); /* QDCOUNT=1 */
  51   MKQUERY_ADDW(0); /* ANCOUNT=0 */
  52   MKQUERY_ADDW(0); /* NSCOUNT=0 */
  53   MKQUERY_ADDW(0); /* ARCOUNT=0 */
  54
  55   MKQUERY_STOP(vb);
  56
  57   return adns_s_ok;
  58 }
  59
  60 static adns_status mkquery_footer(vbuf *vb, adns_rrtype type) {
  61   byte *rqp;
  62
  63   MKQUERY_START(vb);
  64   MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
  65   MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */
  66   MKQUERY_STOP(vb);
  67   assert(vb->used <= vb->avail);
  68
  69   return adns_s_ok;
  70 }
  71
  72 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
  73                           const char *owner, int ol,
  74                           const typeinfo *typei, adns_queryflags flags) {
  75   int ll, c, nlabs;
  76   byte label[255], *rqp;
  77   const char *p, *pe;
  78   adns_status st;
  79
  80   st= mkquery_header(ads,vb,id_r,strlen(owner)+2); if (st) return st;
  81
  82   MKQUERY_START(vb);
  83
  84   p= owner; pe= owner+ol;
  85   nlabs= 0;
  86   while (p!=pe) {
  87     ll= 0;
  88     while (p!=pe && (c= *p++)!='.') {
  89       if (c=='\\') {
  90         if (!(flags & adns_qf_quoteok_query)) return adns_s_querydomaininvalid;
  91         if (ctype_digit(p[0])) {
  92           if (ctype_digit(p[1]) && ctype_digit(p[2])) {
  93             c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
  94             if (c >= 256) return adns_s_querydomaininvalid;
  95           } else {
  96             return adns_s_querydomaininvalid;
  97           }
  98         } else if (!(c= *p++)) {
  99           return adns_s_querydomaininvalid;
 100         }
 101       }
 102       if (!(flags & adns_qf_quoteok_query)) {
 103         if (c == '-') {
 104           if (!ll) return adns_s_querydomaininvalid;
 105         } else if (!ctype_alpha(c) && !ctype_digit(c)) {
 106           return adns_s_querydomaininvalid;
 107         }
 108       }
 109       if (ll == sizeof(label)) return adns_s_querydomaininvalid;
 110       label[ll++]= c;
 111     }
 112     if (!ll) return adns_s_querydomaininvalid;
 113     if (nlabs++ > 63) return adns_s_querydomaintoolong;
 114     MKQUERY_ADDB(ll);
 115     memcpy(rqp,label,ll); rqp+= ll;
 116   }
 117   MKQUERY_ADDB(0);
 118
 119   MKQUERY_STOP(vb);
 120
 121   st= mkquery_footer(vb,typei->type);
 122
 123   return adns_s_ok;
 124 }
 125
 126 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
 127                                   const byte *qd_dgram, int qd_dglen, int qd_begin,
 128                                   adns_rrtype type, adns_queryflags flags) {
 129   byte *rqp;
 130   findlabel_state fls;
 131   int lablen, labstart;
 132   adns_status st;
 133
 134   st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st;
 135
 136   MKQUERY_START(vb);
 137
 138   adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0);
 139   for (;;) {
 140     st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st);
 141     if (!lablen) break;
 142     assert(lablen<255);
 143     MKQUERY_ADDB(lablen);
 144     memcpy(rqp,qd_dgram+labstart,lablen);
 145     rqp+= lablen;
 146   }
 147   MKQUERY_ADDB(0);
 148
 149   MKQUERY_STOP(vb);
 150
 151   st= mkquery_footer(vb,type);
 152
 153   return adns_s_ok;
 154 }
 155
 156 void adns__query_tcp(adns_query qu, struct timeval now) {
 157   byte length[2];
 158   struct iovec iov[2];
 159   int wr, r;
 160   adns_state ads;
 161
 162   if (qu->ads->tcpstate != server_ok) return;
 163
 164   length[0]= (qu->query_dglen&0x0ff00U) >>8;
 165   length[1]= (qu->query_dglen&0x0ff);
 166
 167   ads= qu->ads;
 168   if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2)) return;
 169
 170   timevaladd(&now,TCPMS);
 171   qu->timeout= now;
 172   qu->state= query_tcpsent;
 173
 174   if (ads->tcpsend.used) {
 175     wr= 0;
 176   } else {
 177     iov[0].iov_base= length;
 178     iov[0].iov_len= 2;
 179     iov[1].iov_base= qu->query_dgram;
 180     iov[1].iov_len= qu->query_dglen;
 181     adns__sigpipe_protect(qu->ads);
 182     wr= writev(qu->ads->tcpsocket,iov,2);
 183     adns__sigpipe_unprotect(qu->ads);
 184     if (wr < 0) {
 185       if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 186             errno == ENOBUFS || errno == ENOMEM)) {
 187         adns__tcp_broken(ads,"write",strerror(errno));
 188         return;
 189       }
 190       wr= 0;
 191     }
 192   }
 193
 194   if (wr<2) {
 195     r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
 196     wr= 0;
 197   } else {
 198     wr-= 2;
 199   }
 200   if (wr<qu->query_dglen) {
 201     r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr); assert(r);
 202   }
 203 }
 204
 205 static void query_usetcp(adns_query qu, struct timeval now) {
 206   timevaladd(&now,TCPMS);
 207   qu->timeout= now;
 208   qu->state= query_tcpwait;
 209   LIST_LINK_TAIL(qu->ads->timew,qu);
 210   adns__query_tcp(qu,now);
 211   adns__tcp_tryconnect(qu->ads,now);
 212 }
 213
 214 void adns__query_send(adns_query qu, struct timeval now) {
 215   struct sockaddr_in servaddr;
 216   int serv, r;
 217   adns_state ads;
 218
 219   assert(qu->state == query_tosend);
 220   if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
 221     query_usetcp(qu,now);
 222     return;
 223   }
 224
 225   if (qu->udpretries >= UDPMAXRETRIES) {
 226     adns__query_fail(qu,adns_s_timeout);
 227     return;
 228   }
 229
 230   serv= qu->udpnextserver;
 231   memset(&servaddr,0,sizeof(servaddr));
 232
 233   ads= qu->ads;
 234   servaddr.sin_family= AF_INET;
 235   servaddr.sin_addr= ads->servers[serv].addr;
 236   servaddr.sin_port= htons(DNS_PORT);
 237
 238   r= sendto(ads->udpsocket,qu->query_dgram,qu->query_dglen,0,
 239             (const struct sockaddr*)&servaddr,sizeof(servaddr));
 240   if (r<0 && errno == EMSGSIZE) { query_usetcp(qu,now); return; }
 241   if (r<0) adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno));
 242
 243   timevaladd(&now,UDPRETRYMS);
 244   qu->timeout= now;
 245   qu->udpsent |= (1<<serv);
 246   qu->udpnextserver= (serv+1)%ads->nservers;
 247   qu->udpretries++;
 248   LIST_LINK_TAIL(ads->timew,qu);
 249 }