mdw@git.distorted.org.uk Git - adns/blob - src/query.c

   1 /**/
   2
   3 #include "internal.h"
   4
   5 adns_status adns__mkquery(adns_state ads, const char *owner, int ol, int id,
   6                           adns_rrtype type, adns_queryflags flags, int *qml_r) {
   7   int ll, c, nlabs, qbufreq;
   8   unsigned char label[255], *nqbuf;
   9   const char *p, *pe;
  10
  11 #define MKQUERY_ADDB(b) *nqbuf++= (b)
  12 #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
  13
  14   qbufreq= 12+strlen(owner)+3;
  15   if (ads->qbufavail < qbufreq) {
  16     nqbuf= realloc(ads->qbuf,qbufreq);
  17     if (!nqbuf) return adns_s_nolocalmem;
  18     ads->qbuf= nqbuf; ads->qbufavail= qbufreq;
  19   }
  20   nqbuf= ads->qbuf;
  21
  22   MKQUERY_ADDW(id);
  23   MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
  24   MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
  25   MKQUERY_ADDW(1); /* QDCOUNT=1 */
  26   MKQUERY_ADDW(0); /* ANCOUNT=0 */
  27   MKQUERY_ADDW(0); /* NSCOUNT=0 */
  28   MKQUERY_ADDW(0); /* ARCOUNT=0 */
  29   p= owner; pe= owner+ol;
  30   nlabs= 0;
  31   if (!*p) return adns_s_invaliddomain;
  32   do {
  33     ll= 0;
  34     while (p!=pe && (c= *p++)!='.') {
  35       if (c=='\\') {
  36         if (!(flags & adns_f_anyquote)) return adns_s_invaliddomain;
  37         if (ctype_digit(p[0])) {
  38           if (ctype_digit(p[1]) && ctype_digit(p[2])) {
  39             c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
  40             if (c >= 256) return adns_s_invaliddomain;
  41           } else {
  42             return adns_s_invaliddomain;
  43           }
  44         } else if (!(c= *p++)) {
  45           return adns_s_invaliddomain;
  46         }
  47       }
  48       if (!(flags & adns_f_anyquote)) {
  49         if (ctype_digit(c) || c == '-') {
  50           if (!ll) return adns_s_invaliddomain;
  51         } else if ((c < 'a' || c > 'z') && (c < 'A' && c > 'Z')) {
  52           return adns_s_invaliddomain;
  53         }
  54       }
  55       if (ll == sizeof(label)) return adns_s_invaliddomain;
  56       label[ll++]= c;
  57     }
  58     if (!ll) return adns_s_invaliddomain;
  59     if (nlabs++ > 63) return adns_s_invaliddomain;
  60     MKQUERY_ADDB(ll);
  61     memcpy(nqbuf,label,ll); nqbuf+= ll;
  62   } while (p!=pe);
  63
  64   MKQUERY_ADDB(0);
  65   MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
  66   MKQUERY_ADDW(1); /* QCLASS=IN */
  67
  68   *qml_r= nqbuf - ads->qbuf;
  69
  70   return adns_s_ok;
  71 }
  72
  73 static void quproc_tosend_tcp(adns_state ads, adns_query qu, struct timeval now) {
  74   unsigned char length[2];
  75   struct iovec iov[2];
  76
  77   length[0]= (qu->querylen&0x0ff00U) >>8;
  78   length[1]= (qu->querylen&0x0ff);
  79
  80   adns__tcp_tryconnect(ads);
  81   /* fixme: try sending queries as soon as server comes up */
  82   /* fixme: use vbuf_ensure, and preallocate buffer space */
  83   if (ads->tcpstate != server_ok) return;
  84
  85   DLIST_UNLINK(ads->tosend,qu);
  86   timevaladd(&now,TCPMS);
  87   qu->timeout= now;
  88   qu->senttcpserver= ads->tcpserver;
  89   DLIST_LINKTAIL(ads->timew,qu);
  90
  91   if (ads->opbufused) {
  92     r= 0;
  93   } else {
  94     iov[0].iovbase= length;
  95     iov[0].iov_len= 2;
  96     iov[1].iovbase= qu->querymsg;
  97     iov[1].iov_len= qu->querylen;
  98     r= writev(ads->tcpsocket,iov,2);
  99     if (r < 0) {
 100       if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 101             errno == ENOBUFS || errno == ENOMEM)) {
 102         adns__tcp_broken(ads,"write",strerror(errno));
 103         return;
 104       }
 105       r= 0;
 106     }
 107   }
 108
 109   if (r < qu->querylen+2) {
 110     newopbufused= qu->opbufused + qu->querylen + 2 - r;
 111     if (newopbufused > ads->opbufavail) {
 112       newopbufavail= ads->newopbufused<<1;
 113       newopbuf= realloc(newopbufavail);
 114       if (!newopbuf) {
 115         DLIST_UNLINK(ads->timew,qu);
 116         query_fail(ads,qu,adns_s_nolocalmem);
 117         return;
 118       }
 119       ads->opbuf= newopbuf;
 120       ads->opbufavail= newopbufavail;
 121     }
 122     if (r<2) {
 123       memcpy(ads->opbuf+ads->opbufused,length+r,2-r);
 124       ads->opbufused += (2-r);
 125       r= 0;
 126     } else {
 127       r -= 2;
 128     }
 129     memcpy(ads->opbuf+ads->opbufused,qu->querymsg+r,qu->querylen-r);
 130     ads->opbufused= newopbufused;
 131   }
 132 }
 133
 134 void adns__quproc_tosend(adns_state ads, adns_query qu, struct timeval now) {
 135   /* Query must be on the `tosend' queue, and we guarantee to remove it.
 136    */
 137   struct sockaddr_in servaddr;
 138   int serv;
 139
 140   if (qu->nextudpserver == -1) { quproc_tosend_tcp(ads,qu,now); return; }
 141   if (qu->querylen > UDPMAXDGRAM) {
 142     qu->nextudpserver= -1;
 143     quproc_tosend_tcp(ads,qu,now);
 144     return;
 145   }
 146
 147   if (qu->udpretries >= UDPMAXRETRIES) {
 148     DLIST_UNLINK(ads->tosend,qu);
 149     query_fail(ads,qu,adns_s_notresponding);
 150     return;
 151   }
 152
 153   serv= qu->nextudpserver;
 154   memset(&servaddr,0,sizeof(servaddr));
 155   servaddr.sin_family= AF_INET;
 156   servaddr.sin_addr= ads->servers[serv].addr;
 157   servaddr.sin_port= htons(NSPORT);
 158
 159   r= sendto(ads->udpsocket,qu->querymsg,qu->querylen,0,&servaddr,sizeof(servaddr));
 160   if (r<0 && errno == EMSGSIZE) {
 161     qu->nextudpserver= -1;
 162     quproc_tosend_tcp(ads,qu,now); return;
 163   }
 164   if (r<0) warn("sendto %s failed: %s",inet_ntoa(servaddr.sin_addr),strerror(errno));
 165
 166   DLIST_UNLINK(ads->tosend,qu);
 167   timevaladd(&now,UDPRETRYMS);
 168   qu->timeout= now;
 169   qu->sentudp |= (1<<serv);
 170   qu->nextudpserver= (serv+1)%ads->nservers;
 171   qu->udpretries++;
 172   DLIST_LINKTAIL(ads->timew,qu);
 173 }
 174
 175 void adns__query_fail(adns_state ads, adns_query qu, adns_status stat) {
 176   adns_answer *ans;
 177
 178   ans= qu->answer;
 179   if (!ans) ans= malloc(sizeof(*qu->answer));
 180   if (ans) {
 181     ans->status= stat;
 182     ans->cname= 0;
 183     ans->type= qu->type;
 184     ans->nrrs= 0;
 185   }
 186   qu->answer= ans;
 187   qu->id= -1;
 188   LIST_LINK_TAIL(ads->output,qu);
 189 }