wwan: T4338: changing interface description should not trigger reconnect

Changing the WWAN interface description will trigger an interface reconnect.
Reconnects should only be triggered in changes to the connection parameters
like bond interfaces.

1 files changed, 52 insertions, 23 deletions

diff --git a/src/conf_mode/interfaces-wwan.py b/src/conf_mode/interfaces-wwan.py
index ec01d3cc5..d5e259c74 100755
--- a/src/conf_mode/interfaces-wwan.py
+++ b/src/conf_mode/interfaces-wwan.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2020-2021 VyOS maintainers and contributors
+# Copyright (C) 2020-2022 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -21,6 +21,7 @@ from time import sleep
 
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
+from vyos.configdict import leaf_node_changed
 from vyos.configverify import verify_authentication
 from vyos.configverify import verify_interface_exists
 from vyos.configverify import verify_redirect
@@ -51,6 +52,32 @@ def get_config(config=None):
     base = ['interfaces', 'wwan']
     wwan = get_interface_dict(conf, base)
 
+    # We should only terminate the WWAN session if critical parameters change.
+    # All parameters that can be changed on-the-fly (like interface description)
+    # should not lead to a reconnect!
+    tmp = leaf_node_changed(conf, ['address'])
+    if tmp: wwan.update({'shutdown_required': {}})
+
+    tmp = leaf_node_changed(conf, ['apn'])
+    if tmp: wwan.update({'shutdown_required': {}})
+
+    tmp = leaf_node_changed(conf, ['disable'])
+    if tmp: wwan.update({'shutdown_required': {}})
+
+    tmp = leaf_node_changed(conf, ['vrf'])
+    # leaf_node_changed() returns a list, as VRF is a non-multi node, there
+    # will be only one list element
+    if tmp: wwan.update({'vrf_old': tmp[0]})
+
+    tmp = leaf_node_changed(conf, ['authentication', 'user'])
+    if tmp: wwan.update({'shutdown_required': {}})
+
+    tmp = leaf_node_changed(conf, ['authentication', 'password'])
+    if tmp: wwan.update({'shutdown_required': {}})
+
+    tmp = leaf_node_changed(conf, ['ipv6', 'address', 'autoconf'])
+    if tmp: wwan.update({'shutdown_required': {}})
+
     # We need to know the amount of other WWAN interfaces as ModemManager needs
     # to be started or stopped.
     conf.set_level(base)
@@ -115,11 +142,12 @@ def apply(wwan):
                 break
             sleep(0.250)
 
-    # we only need the modem number. wwan0 -> 0, wwan1 -> 1
-    modem = wwan['ifname'].lstrip('wwan')
-    base_cmd = f'mmcli --modem {modem}'
-    # Number of bearers is limited - always disconnect first
-    cmd(f'{base_cmd} --simple-disconnect')
+    if 'shutdown_required' in wwan:
+        # we only need the modem number. wwan0 -> 0, wwan1 -> 1
+        modem = wwan['ifname'].lstrip('wwan')
+        base_cmd = f'mmcli --modem {modem}'
+        # Number of bearers is limited - always disconnect first
+        cmd(f'{base_cmd} --simple-disconnect')
 
     w = WWANIf(wwan['ifname'])
     if 'deleted' in wwan or 'disable' in wwan:
@@ -136,24 +164,25 @@ def apply(wwan):
 
         return None
 
-    ip_type = 'ipv4'
-    slaac = dict_search('ipv6.address.autoconf', wwan) != None
-    if 'address' in wwan:
-        if 'dhcp' in wwan['address'] and ('dhcpv6' in wwan['address'] or slaac):
-            ip_type = 'ipv4v6'
-        elif 'dhcpv6' in wwan['address'] or slaac:
-            ip_type = 'ipv6'
-        elif 'dhcp' in wwan['address']:
-            ip_type = 'ipv4'
-
-    options = f'ip-type={ip_type},apn=' + wwan['apn']
-    if 'authentication' in wwan:
-        options += ',user={user},password={password}'.format(**wwan['authentication'])
-
-    command = f'{base_cmd} --simple-connect="{options}"'
-    call(command, stdout=DEVNULL)
-    w.update(wwan)
+    if 'shutdown_required' in wwan:
+        ip_type = 'ipv4'
+        slaac = dict_search('ipv6.address.autoconf', wwan) != None
+        if 'address' in wwan:
+            if 'dhcp' in wwan['address'] and ('dhcpv6' in wwan['address'] or slaac):
+                ip_type = 'ipv4v6'
+            elif 'dhcpv6' in wwan['address'] or slaac:
+                ip_type = 'ipv6'
+            elif 'dhcp' in wwan['address']:
+                ip_type = 'ipv4'
+
+        options = f'ip-type={ip_type},apn=' + wwan['apn']
+        if 'authentication' in wwan:
+            options += ',user={user},password={password}'.format(**wwan['authentication'])
 
+        command = f'{base_cmd} --simple-connect="{options}"'
+        call(command, stdout=DEVNULL)
+
+    w.update(wwan)
     return None
 
 if __name__ == '__main__':