See the section 10.2 of RFC6762 for details.
Signed-off-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
DNS_ANSWER_AUTHENTICATED = 1, /* Item has been authenticated */
DNS_ANSWER_CACHEABLE = 2, /* Item is subject to caching */
DNS_ANSWER_SHARED_OWNER = 4, /* For mDNS: RRset may be owner by multiple peers */
+ DNS_ANSWER_CACHE_FLUSH = 8, /* For mDNS: sets cache-flush bit in the rrclass of response records */
} DnsAnswerFlags;
struct DnsAnswerItem {
if (!j->shared_owner)
continue;
- r = dns_packet_append_rr(p, j->rr, NULL, NULL);
+ r = dns_packet_append_rr(p, j->rr, 0, NULL, NULL);
if (r == -EMSGSIZE && p->protocol == DNS_PROTOCOL_MDNS) {
/* For mDNS, if we're unable to stuff all known answers into the given packet,
* allocate a new one, push the RR into that one and link it to the current one.
/* continue with new packet */
p = p->more;
- r = dns_packet_append_rr(p, j->rr, NULL, NULL);
+ r = dns_packet_append_rr(p, j->rr, 0, NULL, NULL);
}
if (r < 0)
return r;
}
-int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start) {
+int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, const DnsAnswerFlags flags, size_t *start) {
size_t saved_size;
+ uint16_t class;
int r;
assert(p);
if (r < 0)
goto fail;
- r = dns_packet_append_uint16(p, k->class, NULL);
+ class = flags & DNS_ANSWER_CACHE_FLUSH ? k->class | MDNS_RR_CACHE_FLUSH : k->class;
+ r = dns_packet_append_uint16(p, class, NULL);
if (r < 0)
goto fail;
return 1;
}
-int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start) {
+int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, const DnsAnswerFlags flags, size_t *start, size_t *rdata_start) {
size_t saved_size, rdlength_offset, end, rdlength, rds;
int r;
saved_size = p->size;
- r = dns_packet_append_key(p, rr->key, NULL);
+ r = dns_packet_append_key(p, rr->key, flags, NULL);
if (r < 0)
goto fail;
assert(p);
DNS_QUESTION_FOREACH(key, q) {
- r = dns_packet_append_key(p, key, NULL);
+ r = dns_packet_append_key(p, key, 0, NULL);
if (r < 0)
return r;
}
int dns_packet_append_answer(DnsPacket *p, DnsAnswer *a) {
DnsResourceRecord *rr;
+ DnsAnswerFlags flags;
int r;
assert(p);
- DNS_ANSWER_FOREACH(rr, a) {
- r = dns_packet_append_rr(p, rr, NULL, NULL);
+ DNS_ANSWER_FOREACH_FLAGS(rr, flags, a) {
+ r = dns_packet_append_rr(p, rr, flags, NULL, NULL);
if (r < 0)
return r;
}
int dns_packet_append_raw_string(DnsPacket *p, const void *s, size_t size, size_t *start);
int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, bool canonical_candidate, size_t *start);
int dns_packet_append_name(DnsPacket *p, const char *name, bool allow_compression, bool canonical_candidate, size_t *start);
-int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *key, size_t *start);
-int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start);
+int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *key, const DnsAnswerFlags flags, size_t *start);
+int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, const DnsAnswerFlags flags, size_t *start, size_t *rdata_start);
int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, int rcode, size_t *start);
int dns_packet_append_question(DnsPacket *p, DnsQuestion *q);
int dns_packet_append_answer(DnsPacket *p, DnsAnswer *a);
if (rr->wire_format && rr->wire_format_canonical == canonical)
return 0;
- r = dns_packet_append_rr(&packet, rr, &start, &rds);
+ r = dns_packet_append_rr(&packet, rr, 0, &start, &rds);
if (r < 0)
return r;
DNS_PACKET_HEADER(p)->qdcount = htobe16(1);
DNS_PACKET_HEADER(p)->arcount = htobe16(1);
- r = dns_packet_append_key(p, rr->key, NULL);
+ r = dns_packet_append_key(p, rr->key, 0, NULL);
if (r < 0)
return r;
- r = dns_packet_append_rr(p, rr, NULL, NULL);
+ r = dns_packet_append_rr(p, rr, 0, NULL, NULL);
if (r < 0)
return r;
answer = dns_answer_new(4);
LIST_FOREACH(addresses, a, scope->link->addresses) {
- r = dns_answer_add(answer, a->mdns_address_rr, 0);
+ r = dns_answer_add(answer, a->mdns_address_rr, 0, DNS_ANSWER_CACHE_FLUSH);
if (r < 0) {
log_debug_errno(r, "Failed to add address RR to answer: %m");
return;
}
- r = dns_answer_add(answer, a->mdns_ptr_rr, 0);
+ r = dns_answer_add(answer, a->mdns_ptr_rr, 0, DNS_ANSWER_CACHE_FLUSH);
if (r < 0) {
log_debug_errno(r, "Failed to add PTR RR to answer: %m");
return;
continue;
add:
- r = dns_packet_append_rr(p, rr, NULL, NULL);
+ r = dns_packet_append_rr(p, rr, 0, NULL, NULL);
if (r < 0)
return r;
if (r < 0)
return r;
- r = dns_packet_append_key(p, t->key, NULL);
+ r = dns_packet_append_key(p, t->key, 0, NULL);
if (r < 0)
return r;
if (qdcount >= UINT16_MAX)
break;
- r = dns_packet_append_key(p, other->key, NULL);
+ r = dns_packet_append_key(p, other->key, 0, NULL);
/*
* If we can't stuff more questions into the packet, just give up.
if (r < 0)
return r;
- r = dns_packet_append_key(p, t->key, NULL);
+ r = dns_packet_append_key(p, t->key, 0, NULL);
if (r < 0)
return r;