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resolved: simplify allocation failure handling in dns_stub_process_query()

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Old code was correct, but let's make things more explicit.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2020-06-05 08:46:08 +02:00
parent b8b46b1ce5
commit ceb17827fa
1 changed files with 14 additions and 16 deletions
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30
src/resolve/resolved-dns-stub.c
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@ -278,7 +278,7 @@ static int dns_stub_stream_complete(DnsStream *s, int error) {
}
static void dns_stub_process_query(Manager *m, DnsStream *s, DnsPacket *p) {
DnsQuery *q = NULL;
_cleanup_(dns_query_freep) DnsQuery *q = NULL;
int r;
assert(m);
@ -289,52 +289,52 @@ static void dns_stub_process_query(Manager *m, DnsStream *s, DnsPacket *p) {
in_addr_is_localhost(p->family, &p->destination) <= 0) {
log_error("Got packet on unexpected IP range, refusing.");
dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL, false);
goto fail;
return;
}
r = dns_packet_extract(p);
if (r < 0) {
log_debug_errno(r, "Failed to extract resources from incoming packet, ignoring packet: %m");
dns_stub_send_failure(m, s, p, DNS_RCODE_FORMERR, false);
goto fail;
return;
}
if (!DNS_PACKET_VERSION_SUPPORTED(p)) {
log_debug("Got EDNS OPT field with unsupported version number.");
dns_stub_send_failure(m, s, p, DNS_RCODE_BADVERS, false);
goto fail;
return;
}
if (dns_type_is_obsolete(p->question->keys[0]->type)) {
log_debug("Got message with obsolete key type, refusing.");
dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP, false);
goto fail;
return;
}
if (dns_type_is_zone_transer(p->question->keys[0]->type)) {
log_debug("Got request for zone transfer, refusing.");
dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP, false);
goto fail;
return;
}
if (!DNS_PACKET_RD(p)) {
/* If the "rd" bit is off (i.e. recursion was not requested), then refuse operation */
log_debug("Got request with recursion disabled, refusing.");
dns_stub_send_failure(m, s, p, DNS_RCODE_REFUSED, false);
goto fail;
return;
}
if (DNS_PACKET_DO(p) && DNS_PACKET_CD(p)) {
log_debug("Got request with DNSSEC CD bit set, refusing.");
dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP, false);
goto fail;
return;
}
r = dns_query_new(m, &q, p->question, p->question, 0, SD_RESOLVED_PROTOCOLS_ALL|SD_RESOLVED_NO_SEARCH);
if (r < 0) {
log_error_errno(r, "Failed to generate query object: %m");
dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL, false);
goto fail;
return;
}
/* Request that the TTL is corrected by the cached time for this lookup, so that we return vaguely useful TTLs */
@ -348,25 +348,23 @@ static void dns_stub_process_query(Manager *m, DnsStream *s, DnsPacket *p) {
/* Remember which queries belong to this stream, so that we can cancel them when the stream
* is disconnected early */
r = set_ensure_put(&s->queries, &trivial_hash_ops, q);
r = set_ensure_put(&s->queries, NULL, q);
if (r < 0) {
log_oom();
goto fail;
return;
}
assert(r > 0);
}
r = dns_query_go(q);
if (r < 0) {
log_error_errno(r, "Failed to start query: %m");
dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL, false);
goto fail;
return;
}
log_debug("Processing query...");
return;
fail:
dns_query_free(q);
TAKE_PTR(q);
}
static int on_dns_stub_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {