release/src/router/dnscrypt/src/plugins/example-ldns-aaaa-blocking/example-ldns-aaaa-blocking.c

   1
   2 #include <stdint.h>
   3
   4 #include <dnscrypt/plugin.h>
   5 #include <ldns/ldns.h>
   6
   7 DCPLUGIN_MAIN(__FILE__);
   8
   9 const char *
  10 dcplugin_description(DCPlugin * const dcplugin)
  11 {
  12     return "Directly return an empty response to AAAA queries";
  13 }
  14
  15 int
  16 dcplugin_init(DCPlugin * const dcplugin, int argc, char *argv[])
  17 {
  18     (void) dcplugin;
  19     (void) argc;
  20     (void) argv;
  21
  22     return 0;
  23 }
  24
  25 DCPluginSyncFilterResult
  26 dcplugin_sync_pre_filter(DCPlugin *dcplugin, DCPluginDNSPacket *dcp_packet)
  27 {
  28     ldns_pkt                 *packet;
  29     ldns_rr_list             *questions;
  30     uint8_t                  *wire_data;
  31     DCPluginSyncFilterResult  result = DCP_SYNC_FILTER_RESULT_OK;
  32
  33     wire_data = dcplugin_get_wire_data(dcp_packet);
  34     ldns_wire2pkt(&packet, wire_data, dcplugin_get_wire_data_len(dcp_packet));
  35     if (packet == NULL) {
  36         return DCP_SYNC_FILTER_RESULT_ERROR;
  37     }
  38     questions = ldns_pkt_question(packet);
  39     if (ldns_rr_list_rr_count(questions) == (size_t) 1U &&
  40         ldns_rr_get_type(ldns_rr_list_rr(questions,
  41                                          (size_t) 0U)) == LDNS_RR_TYPE_AAAA) {
  42         LDNS_QR_SET(wire_data);
  43         LDNS_RA_SET(wire_data);
  44         result = DCP_SYNC_FILTER_RESULT_DIRECT;
  45     }
  46     ldns_pkt_free(packet);
  47
  48     return result;
  49 }