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

   1 /**/
   2
   3 #include "internal.h"
   4
   5 typedef enum {
   6   rcode_noerror,
   7   rcode_formaterror,
   8   rcode_serverfail,
   9   rcode_nxdomain,
  10   rcode_notimp,
  11   rcode_refused
  12 } dns_rcode;
  13
  14 void adns__procdgram(adns_state ads, const byte *dgram, int len, int serv) {
  15   unsigned char *rpp;
  16
  17   if (len<12) {
  18     adns__diag(ads,serv,"received datagram too short for message header (%d)",len);
  19     return;
  20   }
  21   id= GFREPLYW;
  22   f1= GFREPLYB;
  23   f2= GFREPLYB;
  24   qdcount= GFREPLYW;
  25   ancount= GFREPLYW;
  26   nscount= GFREPLYW;
  27   arcount= GFREPLYW;
  28
  29   if (f1&0x80) {
  30     adns__diag(ads,serv,"server sent us a query, not a response");
  31     return;
  32   }
  33   if (f1&0x70) {
  34     adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",
  35                (f1>>4)&0x70);
  36     return;
  37   }
  38   if (!qdcount) {
  39     adns__diag(ads,serv,"server sent reply without quoting our question");
  40     return;
  41   } else if (qdcount>1) {
  42     adns__diag(ads,serv,"server claimed to answer %d questions with one message",
  43                qdcount);
  44     return;
  45   }
  46   for (qu= ads->timew; qu= nqu; qu++) {
  47     nqu= qu->next;
  48     if (qu->id != id) continue;
  49     if (len < qu->querylen) continue;
  50     if (memcmp(qu->querymsg+12,rpp,qu->querylen-12)) continue;
  51     break;
  52   }
  53   if (!qu) {
  54     adns__debug(ads,serv,"reply not found (id=%02x)",id);
  55     return;
  56   }
  57   if (!(f2&0x80)) {
  58     adns__diag(ads,serv,"server is not willing to do recursive lookups for us");
  59     adns__query_fail(ads,qu,adns_s_norecurse);
  60     return;
  61   }
  62   if (!(f1&0x01)) {
  63     adns__diag(ads,serv,"server thinks we didn't ask for recursive lookup");
  64     adns__query_fail(ads,qu,adns_s_serverfaulty);
  65     return;
  66   }
  67   switch (f1&0x0f) {
  68   case 0: /* NOERROR */
  69     break;
  70   case 1: /* Format error */
  71     adns__diag(ads,serv,"server cannot understand our query (Format Error)");
  72     adns__query_fail(ads,qu,adns_s_serverfaulty);
  73     return;
  74   case 2: /* Server failure */
  75     adns__query_fail(ads,qu,adns_s_serverfailure);
  76     return;
  77   case 3: /* Name Error */
  78
  79   qr= f1&0x80;
  80
  81
  82   adns__diag(ads,serv,"received datagram size %d",len);
  83
  84 }