Hi,
On Tue, Jan 09, 2018 at 03:28:22PM +0100, Olivier Houchard wrote:
> Hi Willy,
>
> On Tue, Jan 09, 2018 at 03:17:24PM +0100, Willy Tarreau wrote:
> > Hi Olivier,
> >
> > On Mon, Jan 08, 2018 at 04:35:35PM +0100, Olivier Houchard wrote:
> > > Hi,
> > >
> > > The attached patch attempts to map SRV record weight to haproxy weight
> > > correctly,
> > > SRV weight goes from 0 to 65536 while haproxy uses 0 to 256, so we have to
> > > divide it by 256, and a SRV weight of 0 doesn't mean the server shouldn't
> > > be
> > > used, so we use a minimum weight of 1.
> >
> > From what I'm seeing in the code, it's 0..65535 for the SRV record. And
> > that allows us to simplify it and use the full range of the weight like
> > this :
> >
> >hap_weight = srv_weight / 256 + 1;
> >
> > => 0..255 return 1
> >1..511 return 2
> >...
> >65280..65535 return 256
> >
> > What do you think ?
> >
> > Willy
> >
>
> Sure, sounds good, for some reason I thought the max was 255, but it's
> actually 256, one day I'll learn how to read C.
>
Updated patch attached.
Regards,
Olivier
>From 7043d8da312605b2876286c95a2c0c53d6bd43e5 Mon Sep 17 00:00:00 2001
From: Olivier Houchard
Date: Mon, 8 Jan 2018 16:28:57 +0100
Subject: [PATCH] MINOR: dns: Handle SRV record weight correctly.
A SRV record weight can range from 0 to 65535, while haproxy weight goes
from 0 to 255, 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.
---
include/types/dns.h | 2 +-
src/dns.c | 19 ---
2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/include/types/dns.h b/include/types/dns.h
index b1f068a61..9b1d08df7 100644
--- a/include/types/dns.h
+++ b/include/types/dns.h
@@ -143,7 +143,7 @@ struct dns_answer_item {
int16_t class; /* query class */
int32_t ttl; /* response TTL */
int16_t priority; /* SRV type priority */
- int16_t weight;/* SRV type weight */
+ uint16_tweight;/* SRV type weight */
int16_t port; /* SRV type port */
int16_t data_len; /* number of bytes in target
below */
struct sockaddr address; /* IPv4 or IPv6, network
format */
diff --git a/src/dns.c b/src/dns.c
index fceef2e48..a957710ed 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -522,10 +522,16 @@ static void dns_check_dns_response(struct dns_resolution
*res)
if (srv->srvrq == srvrq && srv->svc_port ==
item->port &&
item->data_len == srv->hostname_dn_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];
- snprintf(weight,
sizeof(weight), "%d", item->weight);
+ snprintf(weight,
sizeof(weight), "%d", ha_weight);
server_parse_weight_change_request(srv, weight);
}
HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
@@ -547,6 +553,7 @@ static void dns_check_dns_response(struct dns_resolution
*res)
if (srv) {
const char *msg = NULL;
char weight[9];
+ int ha_weight;
char hostname[DNS_MAX_NAME_SIZE];
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) &&
!(srv->flags & SRV_F_CHECKPORT))
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
