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/uio.h>
  28
  29 #include "internal.h"
  30
  31 #define MKQUERY_START(vb) (rqp= (vb)->buf+(vb)->used)
  32 #define MKQUERY_ADDB(b) *rqp++= (b)
  33 #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
  34 #define MKQUERY_STOP(vb) ((vb)->used= rqp-(vb)->buf)
  35
  36 static adns_status mkquery_header(adns_state ads, vbuf *vb, int *id_r, int qdlen) {
  37   int id;
  38   byte *rqp;
  39
  40   if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+qdlen+4)) return adns_s_nomemory;
  41
  42   *id_r= id= (ads->nextid++) & 0x0ffff;
  43
  44   vb->used= 0;
  45   MKQUERY_START(vb);
  46
  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   if (!*p) return adns_s_querydomaininvalid;
  87   do {
  88     ll= 0;
  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 (ctype_digit(p[1]) && ctype_digit(p[2])) {
  94             c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
  95             if (c >= 256) return adns_s_querydomaininvalid;
  96           } else {
  97             return adns_s_querydomaininvalid;
  98           }
  99         } else if (!(c= *p++)) {
 100           return adns_s_querydomaininvalid;
 101         }
 102       }
 103       if (!(flags & adns_qf_quoteok_query)) {
 104         if (c == '-') {
 105           if (!ll) return adns_s_querydomaininvalid;
 106         } else if (!ctype_alpha(c) && !ctype_digit(c)) {
 107           return adns_s_querydomaininvalid;
 108         }
 109       }
 110       if (ll == sizeof(label)) return adns_s_querydomaininvalid;
 111       label[ll++]= c;
 112     }
 113     if (!ll) return adns_s_querydomaininvalid;
 114     if (nlabs++ > 63) return adns_s_querydomaintoolong;
 115     MKQUERY_ADDB(ll);
 116     memcpy(rqp,label,ll); rqp+= ll;
 117   } while (p!=pe);
 118   MKQUERY_ADDB(0);
 119
 120   MKQUERY_STOP(vb);
 121
 122   st= mkquery_footer(vb,typei->type);
 123
 124   return adns_s_ok;
 125 }
 126
 127 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
 128                                   const byte *qd_dgram, int qd_dglen, int qd_begin,
 129                                   adns_rrtype type, adns_queryflags flags) {
 130   byte *rqp;
 131   findlabel_state fls;
 132   int lablen, labstart;
 133   adns_status st;
 134
 135   st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st;
 136
 137   MKQUERY_START(vb);
 138
 139   adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0);
 140   for (;;) {
 141     st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st);
 142     if (!lablen) break;
 143     assert(lablen<255);
 144     MKQUERY_ADDB(lablen);
 145     memcpy(rqp,qd_dgram+labstart,lablen);
 146     rqp+= lablen;
 147   }
 148   MKQUERY_ADDB(0);
 149
 150   MKQUERY_STOP(vb);
 151
 152   st= mkquery_footer(vb,type);
 153
 154   return adns_s_ok;
 155 }
 156
 157 void adns__query_tcp(adns_query qu, struct timeval now) {
 158   byte length[2];
 159   struct iovec iov[2];
 160   int wr, r;
 161   adns_state ads;
 162
 163   if (qu->ads->tcpstate != server_ok) return;
 164
 165   length[0]= (qu->query_dglen&0x0ff00U) >>8;
 166   length[1]= (qu->query_dglen&0x0ff);
 167
 168   ads= qu->ads;
 169   if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2)) return;
 170
 171   timevaladd(&now,TCPMS);
 172   qu->timeout= now;
 173   qu->state= query_tcpsent;
 174
 175   if (ads->tcpsend.used) {
 176     wr= 0;
 177   } else {
 178     iov[0].iov_base= length;
 179     iov[0].iov_len= 2;
 180     iov[1].iov_base= qu->query_dgram;
 181     iov[1].iov_len= qu->query_dglen;
 182     adns__sigpipe_protect(qu->ads);
 183     wr= writev(qu->ads->tcpsocket,iov,2);
 184     adns__sigpipe_unprotect(qu->ads);
 185     if (wr < 0) {
 186       if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 187             errno == ENOBUFS || errno == ENOMEM)) {
 188         adns__tcp_broken(ads,"write",strerror(errno));
 189         return;
 190       }
 191       wr= 0;
 192     }
 193   }
 194
 195   if (wr<2) {
 196     r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
 197     wr= 0;
 198   } else {
 199     wr-= 2;
 200   }
 201   if (wr<qu->query_dglen) {
 202     r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr); assert(r);
 203   }
 204 }
 205
 206 static void query_usetcp(adns_query qu, struct timeval now) {
 207   timevaladd(&now,TCPMS);
 208   qu->timeout= now;
 209   qu->state= query_tcpwait;
 210   LIST_LINK_TAIL(qu->ads->timew,qu);
 211   adns__query_tcp(qu,now);
 212   adns__tcp_tryconnect(qu->ads,now);
 213 }
 214
 215 void adns__query_udp(adns_query qu, struct timeval now) {
 216   struct sockaddr_in servaddr;
 217   int serv, r;
 218   adns_state ads;
 219
 220   assert(qu->state == query_udp);
 221   if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) {
 222     query_usetcp(qu,now);
 223     return;
 224   }
 225
 226   if (qu->udpretries >= UDPMAXRETRIES) {
 227     adns__query_fail(qu,adns_s_timeout);
 228     return;
 229   }
 230
 231   serv= qu->udpnextserver;
 232   memset(&servaddr,0,sizeof(servaddr));
 233
 234   ads= qu->ads;
 235   servaddr.sin_family= AF_INET;
 236   servaddr.sin_addr= ads->servers[serv].addr;
 237   servaddr.sin_port= htons(DNS_PORT);
 238
 239   r= sendto(ads->udpsocket,qu->query_dgram,qu->query_dglen,0,&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 }