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 d22c57c1a72c39a569f06eeb6d519290858b3004..fe29662e280f6a2e183a7a30ecc6a7491efa6d0b 100644 (file)
--- a/bgpd/bgp_zebra.c
+++ b/bgpd/bgp_zebra.c
@@ -3187,12 +3187,12 @@ 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;