/** match edns sections */
static int
match_edns(ldns_pkt* q, ldns_pkt* p)
{
if(ldns_pkt_edns_udp_size(q) != ldns_pkt_edns_udp_size(p))
return 0;
if(ldns_pkt_edns_extended_rcode(q) != ldns_pkt_edns_extended_rcode(p))
return 0;
if(ldns_pkt_edns_version(q) != ldns_pkt_edns_version(p))
return 0;
if(ldns_pkt_edns_do(q) != ldns_pkt_edns_do(p))
return 0;
if(ldns_pkt_edns_z(q) != ldns_pkt_edns_z(p))
return 0;
if(ldns_rdf_compare(ldns_pkt_edns_data(q), ldns_pkt_edns_data(p)) != 0)
return 0;
return 1;
}
void truncation_check(evldns_server_request *srq)
{
ldns_pkt *req = srq->request;
ldns_pkt *resp = srq->response;
unsigned int bufsize = 512;
/* if it's TCP, business as usual */
if (srq->is_tcp) {
return;
}
/* otherwise, convert to wire format, if necessary */
if (!srq->wire_response) {
(void) ldns_pkt2wire(&srq->wire_response, resp, &srq->wire_resplen);
}
/* if it's under the RFC 1035 limit, we're OK */
if (srq->wire_resplen <= bufsize) {
return;
}
/* if the client used EDNS, use that new bufsize */
if (ldns_pkt_edns(req)) {
unsigned int ednssize = ldns_pkt_edns_udp_size(req);
if (ednssize > bufsize) {
bufsize = ednssize;
}
/* it fits - we're OK */
if (srq->wire_resplen <= bufsize) {
return;
}
}
/*
* if we got here, it didn't fit - throw away the
* existing wire buffer and the non-question sections
*/
free(srq->wire_response);
LDNS_rr_list_empty_rr_list(ldns_pkt_additional(resp));
LDNS_rr_list_empty_rr_list(ldns_pkt_authority(resp));
LDNS_rr_list_empty_rr_list(ldns_pkt_answer(resp));
/* set the TC bit and reset section counts */
ldns_pkt_set_tc(resp, true);
ldns_pkt_set_ancount(resp, 0);
ldns_pkt_set_nscount(resp, 0);
ldns_pkt_set_arcount(resp, 0);
/* and convert to wire format again */
(void) ldns_pkt2wire(&srq->wire_response, resp, &srq->wire_resplen);
}
ldns_status
ldns_resolver_send_pkt(ldns_pkt **answer, ldns_resolver *r,
ldns_pkt *query_pkt)
{
ldns_pkt *answer_pkt = NULL;
ldns_status stat = LDNS_STATUS_OK;
stat = ldns_send(&answer_pkt, (ldns_resolver *)r, query_pkt);
if (stat != LDNS_STATUS_OK) {
if(answer_pkt) {
ldns_pkt_free(answer_pkt);
answer_pkt = NULL;
}
} else {
/* if tc=1 fall back to EDNS and/or TCP */
/* check for tcp first (otherwise we don't care about tc=1) */
if (!ldns_resolver_usevc(r) && ldns_resolver_fallback(r)) {
if (ldns_pkt_tc(answer_pkt)) {
/* was EDNS0 set? */
if (ldns_pkt_edns_udp_size(query_pkt) == 0) {
ldns_pkt_set_edns_udp_size(query_pkt, 4096);
ldns_pkt_free(answer_pkt);
stat = ldns_send(&answer_pkt, r, query_pkt);
}
/* either way, if it is still truncated, use TCP */
if (stat != LDNS_STATUS_OK ||
ldns_pkt_tc(answer_pkt)) {
ldns_resolver_set_usevc(r, true);
ldns_pkt_free(answer_pkt);
stat = ldns_send(&answer_pkt, r, query_pkt);
ldns_resolver_set_usevc(r, false);
}
}
}
}
if (answer) {
*answer = answer_pkt;
}
return stat;
}
ldns_status
ldns_pkt2buffer_wire(ldns_buffer *buffer, const ldns_pkt *packet)
{
ldns_rr_list *rr_list;
uint16_t i;
/* edns tmp vars */
ldns_rr *edns_rr;
uint8_t edata[4];
(void) ldns_hdr2buffer_wire(buffer, packet);
rr_list = ldns_pkt_question(packet);
if (rr_list) {
for (i = 0; i < ldns_rr_list_rr_count(rr_list); i++) {
(void) ldns_rr2buffer_wire(buffer,
ldns_rr_list_rr(rr_list, i), LDNS_SECTION_QUESTION);
}
}
rr_list = ldns_pkt_answer(packet);
if (rr_list) {
for (i = 0; i < ldns_rr_list_rr_count(rr_list); i++) {
(void) ldns_rr2buffer_wire(buffer,
ldns_rr_list_rr(rr_list, i), LDNS_SECTION_ANSWER);
}
}
rr_list = ldns_pkt_authority(packet);
if (rr_list) {
for (i = 0; i < ldns_rr_list_rr_count(rr_list); i++) {
(void) ldns_rr2buffer_wire(buffer,
ldns_rr_list_rr(rr_list, i), LDNS_SECTION_AUTHORITY);
}
}
rr_list = ldns_pkt_additional(packet);
if (rr_list) {
for (i = 0; i < ldns_rr_list_rr_count(rr_list); i++) {
(void) ldns_rr2buffer_wire(buffer,
ldns_rr_list_rr(rr_list, i), LDNS_SECTION_ADDITIONAL);
}
}
/* add EDNS to additional if it is needed */
if (ldns_pkt_edns(packet)) {
edns_rr = ldns_rr_new();
ldns_rr_set_owner(edns_rr,
ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, "."));
ldns_rr_set_type(edns_rr, LDNS_RR_TYPE_OPT);
ldns_rr_set_class(edns_rr, ldns_pkt_edns_udp_size(packet));
edata[0] = ldns_pkt_edns_extended_rcode(packet);
edata[1] = ldns_pkt_edns_version(packet);
ldns_write_uint16(&edata[2], ldns_pkt_edns_z(packet));
ldns_rr_set_ttl(edns_rr, ldns_read_uint32(edata));
(void)ldns_rr2buffer_wire(buffer, edns_rr, LDNS_SECTION_ADDITIONAL);
ldns_rr_free(edns_rr);
}
/* add TSIG to additional if it is there */
if (ldns_pkt_tsig(packet)) {
(void) ldns_rr2buffer_wire(buffer,
ldns_pkt_tsig(packet), LDNS_SECTION_ADDITIONAL);
}
return LDNS_STATUS_OK;
}
