vyos.util: provide single implementation for get_json_iface_options()

There had been four implementations of "ip -d -j link show interface" scattered
accross the codebase. Those implementations have now been combined into a new
helper:

vyos.util.get_json_iface_options()

(cherry picked from commit f13cc56d665a91ff3fac47df260301afefb1a3a5)

1 files changed, 7 insertions, 15 deletions

diff --git a/src/conf_mode/interfaces-tunnel.py b/src/conf_mode/interfaces-tunnel.py
index 748a9d261..d1d3616f6 100755
--- a/src/conf_mode/interfaces-tunnel.py
+++ b/src/conf_mode/interfaces-tunnel.py
@@ -40,22 +40,12 @@ from vyos.ifconfig import SitIf
 from vyos.ifconfig import Sit6RDIf
 from vyos.template import is_ipv4
 from vyos.template import is_ipv6
-from vyos.util import cmd
+from vyos.util import get_json_iface_options
 from vyos.util import dict_search
 from vyos import ConfigError
 from vyos import airbag
 airbag.enable()
 
-def get_tunnel_encapsulation(interface):
-    """ Returns the used encapsulation protocol for given interface.
-        If interface does not exist, None is returned.
-    """
-    if not os.path.exists(f'/sys/class/net/{interface}'):
-        return None
-    from json import loads
-    tmp = loads(cmd(f'ip -d -j link show {interface}'))[0]
-    return tmp['linkinfo']['info_kind']
-
 def get_config(config=None):
     """
     Retrive CLI config as dictionary. Dictionary can never be empty, as at least
@@ -135,11 +125,13 @@ def generate(tunnel):
     return None
 
 def apply(tunnel):
-    # If a gre-bridge tunnel is already existing we can not "simply" change
-    # local or remote addresses. This returns "Operation not supported" by the
-    # Kernel. There is no other solution to destroy and recreate the tunnel.
     interface = tunnel['ifname']
-    encap = get_tunnel_encapsulation(interface)
+    # If a gretap tunnel is already existing we can not "simply" change local or
+    # remote addresses. This returns "Operation not supported" by the Kernel.
+    # There is no other solution to destroy and recreate the tunnel.
+    encap = ''
+    tmp = get_json_iface_options(interface)
+    if tmp: encap = dict_search('linkinfo.info_kind', tmp)
 
     if 'deleted' in tunnel or 'encapsulation_changed' in tunnel or encap == 'gretap':
         if interface in interfaces():