[ovs-dev] [PATCH ovn] ovn-northd: Fix update of a mac prefix.

[Ilya Maximets]

'smap_add' doesn't check for duplicates.  This leads to having
more than one entry with a 'mac_prefix' key in the 'options' smap.

'ovsdb_datum_sort_unique' removes duplicates before sending the
transaction.  It does that by sorting values and keeping the first one
per key.  In normal case 'mac_prefix' transitions from nothing to
random and it works fine.  However, northd also tries to change
all-zero prefix to random one and this fails, because all-zero prefix
goes first in a sorted map and a new random value gets dropped from
the transaction.  This makes northd to update macs of all ports
on every iteration with a new random mac prefix.

Fix that by replacing smap value and not relying on IDL for removing
duplicates.

Fixes: 39242c106eff ("northd: refactor and split some IPAM functions")
Signed-off-by: Ilya Maximets <i.maximets at ovn.org>
---
 northd/ovn-northd.c |  2 +-
 tests/ovn.at        | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
index ee761cef0..eef752542 100644
--- a/northd/ovn-northd.c
+++ b/northd/ovn-northd.c
@@ -14212,7 +14212,7 @@ ovnnb_db_run(struct northd_context *ctx,
     struct smap options;
     smap_clone(&options, &nb->options);
 
-    smap_add(&options, "mac_prefix", mac_addr_prefix);
+    smap_replace(&options, "mac_prefix", mac_addr_prefix);
 
     if (!monitor_mac) {
         eth_addr_random(&svc_monitor_mac_ea);
diff --git a/tests/ovn.at b/tests/ovn.at
index 5104a6895..30625ec37 100644
--- a/tests/ovn.at
+++ b/tests/ovn.at
@@ -8030,6 +8030,19 @@ mac_prefix=$(ovn-nbctl --wait=sb get NB_Global . options:mac_prefix | tr -d \")
 port_addr=$(ovn-nbctl get Logical-Switch-Port p91 dynamic_addresses | tr -d \")
 AT_CHECK([test "$port_addr" = "${mac_prefix}:00:00:09"], [0], [])
 
+# set mac_prefix to all-zeroes and check it is allocated in a random manner
+ovn-nbctl --wait=hv set NB_Global . options:mac_prefix="00:00:00:00:00:00"
+ovn-nbctl ls-add sw14
+ovn-nbctl --wait=sb set Logical-Switch sw14 other_config:mac_only=true
+ovn-nbctl --wait=sb lsp-add sw14 p141 -- lsp-set-addresses p141 dynamic
+
+mac_prefix=$(ovn-nbctl --wait=sb get NB_Global . options:mac_prefix | tr -d \")
+port_addr=$(ovn-nbctl get Logical-Switch-Port p141 dynamic_addresses | tr -d \")
+AT_CHECK([test "$mac_prefix" != "00:00:00:00:00:00"], [0], [])
+AT_CHECK([test "$port_addr" = "${mac_prefix}:00:00:0a"], [0], [])
+ovn-nbctl --wait=sb lsp-del sw14 p141
+ovn-nbctl --wait=sb ls-del sw14
+
 ovn-nbctl --wait=hv set NB_Global . options:mac_prefix="00:11:22"
 ovn-nbctl ls-add sw10
 ovn-nbctl --wait=sb set Logical-Switch sw10 other_config:ipv6_prefix="ae01::"
-- 
2.31.1