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

   1 /**/
   2
   3 #include "adns-internal.h"
   4
   5 static adns_status 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 ((c >= '0' && c <= '9') || 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 void adns__quproc_tosend(adns_state ads, adns_query qu, struct timeval now) {
  74   /* Query must be on the `tosend' queue, and guarantees to remove it.
  75    * fixme: Do not send more than 512-byte udp datagrams
  76    */
  77   struct sockaddr_in servaddr;
  78   int serv;
  79
  80   if (qu->nextudpserver != -1) {
  81     if (qu->udpretries >= UDPMAXRETRIES) {
  82       DLIST_UNLINK(ads->tosend,qu);
  83       query_fail(ads,qu,adns_s_notresponding);
  84       return;
  85     }
  86     serv= qu->nextudpserver;
  87     memset(&servaddr,0,sizeof(servaddr));
  88     servaddr.sin_family= AF_INET;
  89     servaddr.sin_addr= ads->servers[serv].addr;
  90     servaddr.sin_port= htons(NSPORT);
  91     r= sendto(ads->udpsocket,qu->querymsg,qu->querylen,0,&servaddr,sizeof(servaddr));
  92     if (r<0 && errno == EMSGSIZE) {
  93       qu->nextudpserver= -1;
  94     } else {
  95       if (r<0) {
  96         warn("sendto %s failed: %s",inet_ntoa(servaddr.sin_addr),strerror(errno));
  97       }
  98       DLIST_UNLINK(ads->tosend,qu);
  99       timevaladd(&now,UDPRETRYMS);
 100       qu->timeout= now;
 101       qu->sentudp |= (1<<serv);
 102       qu->nextudpserver= (serv+1)%ads->nservers;
 103       qu->udpretries++;
 104       DLIST_LINKTAIL(ads->timew,qu);
 105       return;
 106     }
 107   }
 108
 109   /* fixme: TCP queries preceded by length */
 110   for (;;) {
 111     adns__tcp_tryconnect(ads);
 112     /* fixme: make this work properly */
 113     serv= tcpserver_get(ads);
 114     if (serv<0) { r=0; break; }
 115     if (ads->opbufused) { r=0; break; }
 116     r= write(ads->tcpsocket,qu->querymsg,qu->querylen);
 117     if (r >= 0) break;
 118     if (errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 119         errno == ENOBUFS || errno == ENOMEM) {
 120       r= 0; break;
 121     }
 122     tcpserver_broken(serv);
 123   }
 124   if (r < qu->querylen) {
 125     newopbufused= qu->opbufused + (qu->querylen-r);
 126     if (newopbufused > ads->opbufavail) {
 127       newopbufavail= ads->newopbufused<<1;
 128       newopbuf= realloc(newopbufavail);
 129       if (!newopbuf) {
 130         DLIST_UNLINK(ads->tosend,qu);
 131         query_fail(ads,qu,adns_s_nolocalmem);
 132         return;
 133       }
 134       ads->opbuf= newopbuf;
 135       ads->opbufavail= newopbufavail;
 136     }
 137     memcpy(ads->opbuf+ads->opbufused,qu->querymsg+r,qu->querylen-r);
 138     ads->opbufused= newopbufused;
 139   }
 140   DLIST_UNLINK(ads->tosend,qu);
 141   timevaladd(&now,TCPMS);
 142   qu->timeout= now;
 143   qu->senttcp |= (1<<qu->nextserver);
 144   DLIST_LINKTAIL(ads->timew,qu);
 145 }
 146
 147 void adns__query_fail(adns_state ads, adns_query qu, adns_status stat) {
 148   adns_answer *ans;
 149
 150   ans= qu->answer;
 151   if (!ans) ans= malloc(sizeof(*qu->answer));
 152   if (ans) {
 153     ans->status= stat;
 154     ans->cname= 0;
 155     ans->type= qu->type;
 156     ans->nrrs= 0;
 157   }
 158   qu->answer= ans;
 159   qu->id= -1;
 160   LIST_LINK_TAIL(ads->output,qu);
 161 }