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);
}
/** Match q edns data to p raw edns data */
static int
match_ednsdata(ldns_pkt* q, struct reply_packet* p)
{
size_t qdlen, pdlen;
uint8_t *qd, *pd;
if(!ldns_pkt_edns(q) || !ldns_pkt_edns_data(q)) {
verbose(3, "No EDNS data\n");
return 0;
}
qdlen = ldns_rdf_size(ldns_pkt_edns_data(q));
pdlen = ldns_buffer_limit(p->raw_ednsdata);
qd = ldns_rdf_data(ldns_pkt_edns_data(q));
pd = ldns_buffer_begin(p->raw_ednsdata);
if( qdlen == pdlen && 0 == memcmp(qd, pd, qdlen) ) return 1;
verbose(3, "EDNS data does not match.\n");
verbose_hex(3, qd, qdlen, "q:");
verbose_hex(3, pd, pdlen, "p:");
return 0;
}
/*
* Copies the packet header data to the buffer in wire format
*/
static ldns_status
ldns_hdr2buffer_wire(ldns_buffer *buffer, const ldns_pkt *packet)
{
uint8_t flags;
uint16_t arcount;
if (ldns_buffer_reserve(buffer, 12)) {
ldns_buffer_write_u16(buffer, ldns_pkt_id(packet));
flags = ldns_pkt_qr(packet) << 7
| ldns_pkt_get_opcode(packet) << 3
| ldns_pkt_aa(packet) << 2
| ldns_pkt_tc(packet) << 1 | ldns_pkt_rd(packet);
ldns_buffer_write_u8(buffer, flags);
flags = ldns_pkt_ra(packet) << 7
/*| ldns_pkt_z(packet) << 6*/
| ldns_pkt_ad(packet) << 5
| ldns_pkt_cd(packet) << 4 | ldns_pkt_get_rcode(packet);
ldns_buffer_write_u8(buffer, flags);
ldns_buffer_write_u16(buffer, ldns_pkt_qdcount(packet));
ldns_buffer_write_u16(buffer, ldns_pkt_ancount(packet));
ldns_buffer_write_u16(buffer, ldns_pkt_nscount(packet));
/* add EDNS0 and TSIG to additional if they are there */
arcount = ldns_pkt_arcount(packet);
if (ldns_pkt_tsig(packet)) {
arcount++;
}
if (ldns_pkt_edns(packet)) {
arcount++;
}
ldns_buffer_write_u16(buffer, arcount);
}
return ldns_buffer_status(buffer);
}
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;
}
/* finds entry in list, or returns NULL */
struct entry*
find_match(struct entry* entries, ldns_pkt* query_pkt,
enum transport_type transport)
{
struct entry* p = entries;
ldns_pkt* reply = NULL;
for(p=entries; p; p=p->next) {
verbose(3, "comparepkt: ");
reply = p->reply_list->reply;
if(p->match_opcode && ldns_pkt_get_opcode(query_pkt) !=
ldns_pkt_get_opcode(reply)) {
verbose(3, "bad opcode\n");
continue;
}
if(p->match_qtype && get_qtype(query_pkt) != get_qtype(reply)) {
verbose(3, "bad qtype\n");
continue;
}
if(p->match_qname) {
if(!get_owner(query_pkt) || !get_owner(reply) ||
ldns_dname_compare(
get_owner(query_pkt), get_owner(reply)) != 0) {
verbose(3, "bad qname\n");
continue;
}
}
if(p->match_subdomain) {
if(!get_owner(query_pkt) || !get_owner(reply) ||
(ldns_dname_compare(get_owner(query_pkt),
get_owner(reply)) != 0 &&
!ldns_dname_is_subdomain(
get_owner(query_pkt), get_owner(reply))))
{
verbose(3, "bad subdomain\n");
continue;
}
}
if(p->match_serial && get_serial(query_pkt) != p->ixfr_soa_serial) {
verbose(3, "bad serial\n");
continue;
}
if(p->match_do && !ldns_pkt_edns_do(query_pkt)) {
verbose(3, "no DO bit set\n");
continue;
}
if(p->match_noedns && ldns_pkt_edns(query_pkt)) {
verbose(3, "bad; EDNS OPT present\n");
continue;
}
if(p->match_transport != transport_any && p->match_transport != transport) {
verbose(3, "bad transport\n");
continue;
}
if(p->match_all && !match_all(query_pkt, reply, p->match_ttl)) {
verbose(3, "bad allmatch\n");
continue;
}
verbose(3, "match!\n");
return p;
}
return NULL;
}
