lib: fix interface configuration after vrf change

This commit fixes the following problem:

- enter the interface node
- move the interface to another VRF
- try to continue configuring the interface

It is not possible to continue configuration because the XPath stored in
the vty doesn't correspond with the actual state of the system anymore.

For example:
```
nfware# conf
nfware(config)# interface enp2s0

<-- move the enp2s0 to a different VRF -->

nfware(config-if)# ip router isis 1
% Failed to get iface dnode in candidate DB
```

To fix the issue, go through all connected vty shells and update the
stored XPath.

Suggested-by: Renato Westphal <renato@opensourcerouting.org>
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/lib/if.c b/lib/if.c
index b3803141df..e37b4f55b0 100644
--- a/lib/if.c
+++ b/lib/if.c
@@ -266,20 +266,23 @@ void if_update_to_new_vrf(struct interface *ifp, vrf_id_t vrf_id)
 		char oldpath[XPATH_MAXLEN];
 		char newpath[XPATH_MAXLEN];
 
-		if_dnode = yang_dnode_getf(
-			running_config->dnode,
-			"/frr-interface:lib/interface[name='%s'][vrf='%s']/vrf",
-			ifp->name, old_vrf->name);
+		snprintf(oldpath, sizeof(oldpath),
+			 "/frr-interface:lib/interface[name='%s'][vrf='%s']",
+			 ifp->name, old_vrf->name);
+		snprintf(newpath, sizeof(newpath),
+			 "/frr-interface:lib/interface[name='%s'][vrf='%s']",
+			 ifp->name, vrf->name);
+
+		if_dnode = yang_dnode_getf(running_config->dnode, "%s/vrf",
+					   oldpath);
 
 		if (if_dnode) {
-			yang_dnode_get_path(lyd_parent(if_dnode), oldpath,
-					    sizeof(oldpath));
 			yang_dnode_change_leaf(if_dnode, vrf->name);
-			yang_dnode_get_path(lyd_parent(if_dnode), newpath,
-					    sizeof(newpath));
 			nb_running_move_tree(oldpath, newpath);
 			running_config->version++;
 		}
+
+		vty_update_xpath(oldpath, newpath);
 	}
 }