/** check request sanity.
* @param pkt: the wire packet to examine for sanity.
* @param worker: parameters for checking.
* @return error code, 0 OK, or -1 discard.
*/
static int
worker_check_request(sldns_buffer* pkt, struct worker* worker)
{
if(sldns_buffer_limit(pkt) < LDNS_HEADER_SIZE) {
verbose(VERB_QUERY, "request too short, discarded");
return -1;
}
if(sldns_buffer_limit(pkt) > NORMAL_UDP_SIZE &&
worker->daemon->cfg->harden_large_queries) {
verbose(VERB_QUERY, "request too large, discarded");
return -1;
}
if(LDNS_QR_WIRE(sldns_buffer_begin(pkt))) {
verbose(VERB_QUERY, "request has QR bit on, discarded");
return -1;
}
if(LDNS_TC_WIRE(sldns_buffer_begin(pkt))) {
LDNS_TC_CLR(sldns_buffer_begin(pkt));
verbose(VERB_QUERY, "request bad, has TC bit on");
return worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
}
if(LDNS_OPCODE_WIRE(sldns_buffer_begin(pkt)) != LDNS_PACKET_QUERY) {
verbose(VERB_QUERY, "request unknown opcode %d",
LDNS_OPCODE_WIRE(sldns_buffer_begin(pkt)));
return worker_err_ratelimit(worker, LDNS_RCODE_NOTIMPL);
}
if(LDNS_QDCOUNT(sldns_buffer_begin(pkt)) != 1) {
verbose(VERB_QUERY, "request wrong nr qd=%d",
LDNS_QDCOUNT(sldns_buffer_begin(pkt)));
return worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
}
if(LDNS_ANCOUNT(sldns_buffer_begin(pkt)) != 0) {
verbose(VERB_QUERY, "request wrong nr an=%d",
LDNS_ANCOUNT(sldns_buffer_begin(pkt)));
return worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
}
if(LDNS_NSCOUNT(sldns_buffer_begin(pkt)) != 0) {
verbose(VERB_QUERY, "request wrong nr ns=%d",
LDNS_NSCOUNT(sldns_buffer_begin(pkt)));
return worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
}
if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) > 1) {
verbose(VERB_QUERY, "request wrong nr ar=%d",
LDNS_ARCOUNT(sldns_buffer_begin(pkt)));
return worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
}
return 0;
}
/** test a packet */
static void
testpkt(sldns_buffer* pkt, struct alloc_cache* alloc, sldns_buffer* out,
const char* hex)
{
struct query_info qi;
struct reply_info* rep = 0;
int ret;
uint16_t id;
uint16_t flags;
uint32_t timenow = 0;
struct regional* region = regional_create();
struct edns_data edns;
hex_to_buf(pkt, hex);
memmove(&id, sldns_buffer_begin(pkt), sizeof(id));
if(sldns_buffer_limit(pkt) < 2)
flags = 0;
else memmove(&flags, sldns_buffer_at(pkt, 2), sizeof(flags));
flags = ntohs(flags);
ret = reply_info_parse(pkt, alloc, &qi, &rep, region, &edns);
if(ret != 0) {
char rbuf[16];
sldns_wire2str_rcode_buf(ret, rbuf, sizeof(rbuf));
if(vbmp) printf("parse code %d: %s\n", ret, rbuf);
if(ret == LDNS_RCODE_FORMERR) {
unit_assert(!check_formerr_gone);
checkformerr(pkt);
}
unit_assert(ret != LDNS_RCODE_SERVFAIL);
} else if(!check_formerr_gone) {
const size_t lim = 512;
ret = reply_info_encode(&qi, rep, id, flags, out, timenow,
region, 65535, (int)(edns.bits & EDNS_DO) );
unit_assert(ret != 0); /* udp packets should fit */
attach_edns_record(out, &edns);
if(vbmp) printf("inlen %u outlen %u\n",
(unsigned)sldns_buffer_limit(pkt),
(unsigned)sldns_buffer_limit(out));
if(!check_nosameness)
test_buffers(pkt, out);
if(check_rrsigs)
check_the_rrsigs(&qi, rep);
if(sldns_buffer_limit(out) > lim) {
ret = reply_info_encode(&qi, rep, id, flags, out,
timenow, region,
lim - calc_edns_field_size(&edns),
(int)(edns.bits & EDNS_DO));
unit_assert(ret != 0); /* should fit, but with TC */
attach_edns_record(out, &edns);
if( LDNS_QDCOUNT(sldns_buffer_begin(out)) !=
LDNS_QDCOUNT(sldns_buffer_begin(pkt)) ||
LDNS_ANCOUNT(sldns_buffer_begin(out)) !=
LDNS_ANCOUNT(sldns_buffer_begin(pkt)) ||
LDNS_NSCOUNT(sldns_buffer_begin(out)) !=
LDNS_NSCOUNT(sldns_buffer_begin(pkt)))
unit_assert(
LDNS_TC_WIRE(sldns_buffer_begin(out)));
/* must set TC bit if shortened */
unit_assert(sldns_buffer_limit(out) <= lim);
}
}
query_info_clear(&qi);
reply_info_parsedelete(rep, alloc);
regional_destroy(region);
}