From: Yuan-96 <294754...@qq.com>
While the CentOS 8 requests an IPv4 DNS record, the response will be slow
without a correct IPv6 DNS record on server. It will send a DNS request(type
AAAA) message first but ovn controller will not reply. And the DNS request(type
A) message will be sent until DNS request(type AAAA) is timeout.
So the DNS client may expect to receive a reponse with RCODE 3(RFC1035. Name
Error) instead of nothing when DNS record is not available. And this patch is
for that.
Signed-off-by: Yuan-96 <294754...@qq.com>
---
controller/pinctrl.c | 72 +++++++++++++++++++++++++++-------------------------
1 file changed, 37 insertions(+), 35 deletions(-)
diff --git a/controller/pinctrl.c b/controller/pinctrl.c
index 1b8b475..a2fc1a2 100644
--- a/controller/pinctrl.c
+++ b/controller/pinctrl.c
@@ -2952,47 +2952,41 @@ pinctrl_handle_dns_lookup(
}
ds_destroy(&query_name);
- if (!answer_data) {
- goto exit;
- }
- uint16_t ancount = 0;
- uint64_t dns_ans_stub[128 / 8];
- struct ofpbuf dns_answer = OFPBUF_STUB_INITIALIZER(dns_ans_stub);
+ if (answer_data) {
+ uint16_t ancount = 0;
+ uint64_t dns_ans_stub[128 / 8];
+ struct ofpbuf dns_answer = OFPBUF_STUB_INITIALIZER(dns_ans_stub);
- if (query_type == DNS_QUERY_TYPE_PTR) {
- dns_build_ptr_answer(&dns_answer, in_queryname, idx, answer_data);
- ancount++;
- } else {
- struct lport_addresses ip_addrs;
- if (!extract_ip_addresses(answer_data, &ip_addrs)) {
- goto exit;
- }
+ if (query_type == DNS_QUERY_TYPE_PTR) {
+ dns_build_ptr_answer(&dns_answer, in_queryname, idx, answer_data);
+ ancount++;
+ } else {
+ struct lport_addresses ip_addrs;
+ if (!extract_ip_addresses(answer_data, &ip_addrs)) {
+ goto exit;
+ }
- if (query_type == DNS_QUERY_TYPE_A ||
- query_type == DNS_QUERY_TYPE_ANY) {
- for (size_t i = 0; i < ip_addrs.n_ipv4_addrs; i++) {
- dns_build_a_answer(&dns_answer, in_queryname, idx,
- ip_addrs.ipv4_addrs[i].addr);
- ancount++;
+ if (query_type == DNS_QUERY_TYPE_A ||
+ query_type == DNS_QUERY_TYPE_ANY) {
+ for (size_t i = 0; i < ip_addrs.n_ipv4_addrs; i++) {
+ dns_build_a_answer(&dns_answer, in_queryname, idx,
+ ip_addrs.ipv4_addrs[i].addr);
+ ancount++;
+ }
}
- }
- if (query_type == DNS_QUERY_TYPE_AAAA ||
- query_type == DNS_QUERY_TYPE_ANY) {
- for (size_t i = 0; i < ip_addrs.n_ipv6_addrs; i++) {
- dns_build_aaaa_answer(&dns_answer, in_queryname, idx,
- &ip_addrs.ipv6_addrs[i].addr);
- ancount++;
+ if (query_type == DNS_QUERY_TYPE_AAAA ||
+ query_type == DNS_QUERY_TYPE_ANY) {
+ for (size_t i = 0; i < ip_addrs.n_ipv6_addrs; i++) {
+ dns_build_aaaa_answer(&dns_answer, in_queryname, idx,
+ &ip_addrs.ipv6_addrs[i].addr);
+ ancount++;
+ }
}
+ destroy_lport_addresses(&ip_addrs);
}
- destroy_lport_addresses(&ip_addrs);
- }
-
- if (!ancount) {
- ofpbuf_uninit(&dns_answer);
- goto exit;
}
uint16_t new_l4_size = ntohs(in_udp->udp_len) + dns_answer.size;
@@ -3023,6 +3017,12 @@ pinctrl_handle_dns_lookup(
/* Set the response bit to 1 in the flags. */
out_dns_header->lo_flag |= 0x80;
+ if (ancount == 0) {
+ /*Set the reply code bits to 0011 in the flags
+ *when here is no dns record. */
+ out_dns_header->hi_flag |= 0x03;
+ }
+
/* Set the answer RRs. */
out_dns_header->ancount = htons(ancount);
out_dns_header->arcount = 0;
@@ -3030,8 +3030,10 @@ pinctrl_handle_dns_lookup(
/* Copy the Query section. */
dp_packet_put(&pkt_out, dp_packet_data(pkt_in), dp_packet_size(pkt_in));
- /* Copy the answer sections. */
- dp_packet_put(&pkt_out, dns_answer.data, dns_answer.size);
+ if (dns_answer.size > 0) {
+ /* Copy the answer sections. */
+ dp_packet_put(&pkt_out, dns_answer.data, dns_answer.size);
+ }
ofpbuf_uninit(&dns_answer);
out_udp->udp_len = htons(new_l4_size);
--
1.8.3.1
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