Thx to 2 people who spotted a bug in my patch, (missing parenthesis). here is the updated version.
On Mon, Oct 21, 2019 at 3:59 PM Baptiste <[email protected]> wrote: > hi there, > > Following up some recent discussion about SRV record's weight and server > weight in HAProxy, we spotted a bug in the current code: when weight in SRV > record is set to 0, then server weight in HAProxy was 1... > Thanks to Willy for proposing the solution applied into that patch. > > Baptiste >
From a8467daeb5cf2129f5471ef117039f778c2842fd Mon Sep 17 00:00:00 2001 From: Baptiste Assmann <[email protected]> Date: Mon, 21 Oct 2019 15:13:48 +0200 Subject: [PATCH] BUG/MINOR: dns: allow srv record weight set to 0 Processing of SRV record weight was inaccurate and when a SRV record's weight was set to 0, HAProxy enforced it to '1'. This patch aims at fixing this without breaking compability with previous behavior. Backport status: 1.8 to 2.0 --- src/dns.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/src/dns.c b/src/dns.c index 0ce6e8302..3e1bb421e 100644 --- a/src/dns.c +++ b/src/dns.c @@ -543,10 +543,12 @@ static void dns_check_dns_response(struct dns_resolution *res) !memcmp(srv->hostname_dn, item->target, item->data_len)) { int ha_weight; - /* Make sure weight is at least 1, so - * that the server will be used. + /* DNS weight range if from 0 to 65535 + * HAProxy weight is from 0 to 255 + * The rule below ensures that weight 0 is well respected + * while allowing a "mapping" from DNS weight into HAProxy's one. */ - ha_weight = item->weight / 256 + 1; + ha_weight = (item->weight + 255) / 256; if (srv->uweight != ha_weight) { char weight[9]; @@ -590,10 +592,12 @@ static void dns_check_dns_response(struct dns_resolution *res) !(srv->flags & SRV_F_CHECKPORT)) srv->check.port = item->port; - /* Make sure weight is at least 1, so - * that the server will be used. + /* DNS weight range if from 0 to 65535 + * HAProxy weight is from 0 to 255 + * The rule below ensures that weight 0 is well respected + * while allowing a "mapping" from DNS weight into HAProxy's one. */ - ha_weight = item->weight / 256 + 1; + ha_weight = (item->weight + 255) / 256; snprintf(weight, sizeof(weight), "%d", ha_weight); server_parse_weight_change_request(srv, weight); -- 2.17.1
