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resolved: answer all mDNS questions found in packet

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According to p5.3 of RFC6762 (Multicast DNS) one mDNS query message
can contain more than one question sections.

Generate answers for all found questions and put them to a reply
message.
This commit is contained in:
Dmitry Rozhkov 2017-09-29 14:13:47 +03:00
parent 9e32914aa5
commit 9c5e7b73f7
1 changed files with 15 additions and 8 deletions
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23
src/resolve/resolved-mdns.c
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@ -69,7 +69,7 @@ eaddrinuse:
}
static int mdns_scope_process_query(DnsScope *s, DnsPacket *p) {
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
_cleanup_(dns_answer_unrefp) DnsAnswer *full_answer = NULL;
_cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL;
DnsResourceKey *key = NULL;
bool tentative = false;
@ -82,17 +82,24 @@ static int mdns_scope_process_query(DnsScope *s, DnsPacket *p) {
if (r < 0)
return log_debug_errno(r, "Failed to extract resource records from incoming packet: %m");
/* TODO: there might be more than one question in mDNS queries. */
assert_return((dns_question_size(p->question) > 0), -EINVAL);
key = p->question->keys[0];
r = dns_zone_lookup(&s->zone, key, 0, &answer, &soa, &tentative);
if (r < 0)
return log_debug_errno(r, "Failed to lookup key: %m");
if (r == 0)
DNS_QUESTION_FOREACH(key, p->question) {
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
r = dns_zone_lookup(&s->zone, key, 0, &answer, &soa, &tentative);
if (r < 0)
return log_debug_errno(r, "Failed to lookup key: %m");
r = dns_answer_extend(&full_answer, answer);
if (r < 0)
return log_debug_errno(r, "Failed to extend answer: %m");
}
if (dns_answer_isempty(full_answer))
return 0;
r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, NULL, answer, NULL, false, &reply);
r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, NULL, full_answer, NULL, false, &reply);
if (r < 0)
return log_debug_errno(r, "Failed to build reply packet: %m");