bgpd: Fix the order of NULL check and ZAPI decode

When BGP receives an SRV6_LOCATOR_ADD message from zebra, it calls the
`bgp_zebra_process_srv6_locator_add()` function to process the message.
`bgp_zebra_process_srv6_locator_add()` decodes the message first, and
then if the pointer to the default BGP instance is NULL (i.e. the
default BGP instance is not configured yet), it returns early without
doing anything and without using the decoded message information.

This commit fixes the order of the operations executed by
`bgp_zebra_process_srv6_locator_add()`. We first ensure that the default
BGP instance is ready and we return early if it is not. Then, we decode
the message and do something with the information contained in it.

Signed-off-by: Carmine Scarpitta <cscarpit@cisco.com>
(cherry picked from commit bdc2c7bc5473b5582419702211c22e5d29bf0631)

diff --git a/bgpd/bgp_zebra.c b/bgpd/bgp_zebra.c
index 77b7a0c9ec99a4e03cc3d716cdb3bedbf853364c..bc51d14b392b560720fbe20690539e639ae4e8d5 100644 (file)
--- a/bgpd/bgp_zebra.c
+++ b/bgpd/bgp_zebra.c
@@ -3197,12 +3197,12 @@ static int bgp_zebra_process_srv6_locator_add(ZAPI_CALLBACK_ARGS)
        struct bgp *bgp = bgp_get_default();
        const char *loc_name = bgp->srv6_locator_name;
 
-       if (zapi_srv6_locator_decode(zclient->ibuf, &loc) < 0)
-               return -1;
-
        if (!bgp || !bgp->srv6_enabled)
                return 0;
 
+       if (zapi_srv6_locator_decode(zclient->ibuf, &loc) < 0)
+               return -1;
+
        if (bgp_zebra_srv6_manager_get_locator_chunk(loc_name) < 0)
                return -1;