MINOR: dns: Handle SRV record weight correctly.

A SRV record weight can range from 0 to 65535, while haproxy weight goes
from 0 to 256, so we have to divide it by 256 before handing it to haproxy.
Also, a SRV record with a weight of 0 doesn't mean the server shouldn't be
used, so use a minimum weight of 1.

This should probably be backported to 1.8.
This commit is contained in:
Olivier Houchard 2018-01-08 16:28:57 +01:00 committed by Willy Tarreau
parent 119a5f10e4
commit 2ec2db9725
2 changed files with 17 additions and 4 deletions

View File

@ -143,7 +143,7 @@ struct dns_answer_item {
int16_t class; /* query class */ int16_t class; /* query class */
int32_t ttl; /* response TTL */ int32_t ttl; /* response TTL */
int16_t priority; /* SRV type priority */ int16_t priority; /* SRV type priority */
int16_t weight; /* SRV type weight */ uint16_t weight; /* SRV type weight */
int16_t port; /* SRV type port */ int16_t port; /* SRV type port */
int16_t data_len; /* number of bytes in target below */ int16_t data_len; /* number of bytes in target below */
struct sockaddr address; /* IPv4 or IPv6, network format */ struct sockaddr address; /* IPv4 or IPv6, network format */

View File

@ -522,10 +522,16 @@ static void dns_check_dns_response(struct dns_resolution *res)
if (srv->srvrq == srvrq && srv->svc_port == item->port && if (srv->srvrq == srvrq && srv->svc_port == item->port &&
item->data_len == srv->hostname_dn_len && item->data_len == srv->hostname_dn_len &&
!memcmp(srv->hostname_dn, item->target, item->data_len)) { !memcmp(srv->hostname_dn, item->target, item->data_len)) {
if (srv->uweight != item->weight) { int ha_weight;
/* Make sure weight is at least 1, so
* that the server will be used.
*/
ha_weight = item->weight / 256 + 1;
if (srv->uweight != ha_weight) {
char weight[9]; char weight[9];
snprintf(weight, sizeof(weight), "%d", item->weight); snprintf(weight, sizeof(weight), "%d", ha_weight);
server_parse_weight_change_request(srv, weight); server_parse_weight_change_request(srv, weight);
} }
HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock); HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
@ -547,6 +553,7 @@ static void dns_check_dns_response(struct dns_resolution *res)
if (srv) { if (srv) {
const char *msg = NULL; const char *msg = NULL;
char weight[9]; char weight[9];
int ha_weight;
char hostname[DNS_MAX_NAME_SIZE]; char hostname[DNS_MAX_NAME_SIZE];
if (dns_dn_label_to_str(item->target, item->data_len+1, if (dns_dn_label_to_str(item->target, item->data_len+1,
@ -563,7 +570,13 @@ static void dns_check_dns_response(struct dns_resolution *res)
if ((srv->check.state & CHK_ST_CONFIGURED) && if ((srv->check.state & CHK_ST_CONFIGURED) &&
!(srv->flags & SRV_F_CHECKPORT)) !(srv->flags & SRV_F_CHECKPORT))
srv->check.port = item->port; srv->check.port = item->port;
snprintf(weight, sizeof(weight), "%d", item->weight);
/* Make sure weight is at least 1, so
* that the server will be used.
*/
ha_weight = item->weight / 256 + 1;
snprintf(weight, sizeof(weight), "%d", ha_weight);
server_parse_weight_change_request(srv, weight); server_parse_weight_change_request(srv, weight);
HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock); HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
} }