vyos.util: add common helper to load kernel modules

l2tpv3, wireguard, wirelessmodem, nat all require additional Kernel modules
to be present on the system. Each and every interface implemented their own
way of loading a module - by copying code.

Use a generic function, vyos.util.check_kmod() to load any arbitrary kernel
module passed as string or list.

6 files changed, 30 insertions, 46 deletions

diff --git a/python/vyos/util.py b/python/vyos/util.py
index 924df6b3a..7234be6cb 100644
--- a/python/vyos/util.py
+++ b/python/vyos/util.py
@@ -652,3 +652,12 @@ def get_bridge_member_config(conf, br, intf):
 
     conf.set_level(old_level)
     return memberconf
+
+def check_kmod(k_mod):
+    """ Common utility function to load required kernel modules on demand """
+    if isinstance(k_mod, str):
+        k_mod = k_mod.split()
+    for module in k_mod:
+        if not os.path.exists(f'/sys/module/{module}'):
+            if call(f'modprobe {module}') != 0:
+                raise ConfigError(f'Loading Kernel module {module} failed')
diff --git a/src/conf_mode/interfaces-l2tpv3.py b/src/conf_mode/interfaces-l2tpv3.py
index 4ff0bcb57..866419f2c 100755
--- a/src/conf_mode/interfaces-l2tpv3.py
+++ b/src/conf_mode/interfaces-l2tpv3.py
@@ -24,11 +24,14 @@ from vyos.config import Config
 from vyos.ifconfig import L2TPv3If, Interface
 from vyos import ConfigError
 from vyos.util import call
+from vyos.util import check_kmod
 from vyos.validate import is_member, is_addr_assigned
 
 from vyos import airbag
 airbag.enable()
 
+k_mod = ['l2tp_eth', 'l2tp_netlink', 'l2tp_ip', 'l2tp_ip6']
+
 default_config_data = {
     'address': [],
     'deleted': False,
@@ -53,13 +56,6 @@ default_config_data = {
     'tunnel_id': ''
 }
 
-def check_kmod():
-    modules = ['l2tp_eth', 'l2tp_netlink', 'l2tp_ip', 'l2tp_ip6']
-    for module in modules:
-        if not os.path.exists(f'/sys/module/{module}'):
-            if call(f'modprobe {module}') != 0:
-                raise ConfigError(f'Loading Kernel module {module} failed')
-
 def get_config():
     l2tpv3 = deepcopy(default_config_data)
     conf = Config()
@@ -283,7 +279,7 @@ def apply(l2tpv3):
 
 if __name__ == '__main__':
     try:
-        check_kmod()
+        check_kmod(k_mod)
         c = get_config()
         verify(c)
         generate(c)
diff --git a/src/conf_mode/interfaces-wireguard.py b/src/conf_mode/interfaces-wireguard.py
index c24c9a7ce..982aefa5f 100755
--- a/src/conf_mode/interfaces-wireguard.py
+++ b/src/conf_mode/interfaces-wireguard.py
@@ -25,6 +25,7 @@ from vyos.config import Config
 from vyos.configdict import list_diff
 from vyos.ifconfig import WireGuardIf
 from vyos.util import chown, chmod_750, call
+from vyos.util import check_kmod
 from vyos.validate import is_member, is_ipv6
 from vyos import ConfigError
 
@@ -32,6 +33,7 @@ from vyos import airbag
 airbag.enable()
 
 kdir = r'/config/auth/wireguard'
+k_mod = 'wireguard'
 
 default_config_data = {
     'intfc': '',
@@ -50,14 +52,6 @@ default_config_data = {
     'vrf': ''
 }
 
-def _check_kmod():
-    modules = ['wireguard']
-    for module in modules:
-        if not os.path.exists(f'/sys/module/{module}'):
-            if call(f'modprobe {module}') != 0:
-                raise ConfigError(f'Loading Kernel module {module} failed')
-
-
 def _migrate_default_keys():
     if os.path.exists(f'{kdir}/private.key') and not os.path.exists(f'{kdir}/default/private.key'):
         location = f'{kdir}/default'
@@ -315,7 +309,7 @@ def apply(wg):
 
 if __name__ == '__main__':
     try:
-        _check_kmod()
+        check_kmod(k_mod)
         _migrate_default_keys()
         c = get_config()
         verify(c)
diff --git a/src/conf_mode/interfaces-wirelessmodem.py b/src/conf_mode/interfaces-wirelessmodem.py
index ec5a85e54..0964a8f4d 100755
--- a/src/conf_mode/interfaces-wirelessmodem.py
+++ b/src/conf_mode/interfaces-wirelessmodem.py
@@ -29,12 +29,7 @@ from vyos import ConfigError
 from vyos import airbag
 airbag.enable()
 
-def check_kmod():
-    modules = ['option', 'usb_wwan', 'usbserial']
-    for module in modules:
-        if not os.path.exists(f'/sys/module/{module}'):
-            if call(f'modprobe {module}') != 0:
-                raise ConfigError(f'Loading Kernel module {module} failed')
+k_mod = ['option', 'usb_wwan', 'usbserial']
 
 def find_device_file(device):
     """ Recurively search /dev for the given device file and return its full path.
@@ -153,7 +148,7 @@ def apply(wwan):
 
 if __name__ == '__main__':
     try:
-        check_kmod()
+        check_kmod(k_mod)
         c = get_config()
         verify(c)
         generate(c)
diff --git a/src/conf_mode/nat.py b/src/conf_mode/nat.py
index 2299717a8..dd34dfd66 100755
--- a/src/conf_mode/nat.py
+++ b/src/conf_mode/nat.py
@@ -24,13 +24,17 @@ from netifaces import interfaces
 
 from vyos.config import Config
 from vyos.template import render
-from vyos.util import call, cmd
+from vyos.util import call
+from vyos.util import cmd
+from vyos.util import check_kmod
 from vyos.validate import is_addr_assigned
 from vyos import ConfigError
 
 from vyos import airbag
 airbag.enable()
 
+k_mod = ['nft_nat', 'nft_chain_nat_ipv4']
+
 default_config_data = {
     'deleted': False,
     'destination': [],
@@ -44,15 +48,6 @@ default_config_data = {
 
 iptables_nat_config = '/tmp/vyos-nat-rules.nft'
 
-def _check_kmod():
-    """ load required Kernel modules """
-    modules = ['nft_nat', 'nft_chain_nat_ipv4']
-    for module in modules:
-        if not os.path.exists(f'/sys/module/{module}'):
-            if call(f'modprobe {module}') != 0:
-                raise ConfigError(f'Loading Kernel module {module} failed')
-
-
 def get_handler(json, chain, target):
     """ Get nftable rule handler number of given chain/target combination.
     Handler is required when adding NAT/Conntrack helper targets """
@@ -269,7 +264,7 @@ def apply(nat):
 
 if __name__ == '__main__':
     try:
-        _check_kmod()
+        check_kmod(k_mod)
         c = get_config()
         verify(c)
         generate(c)
diff --git a/src/op_mode/wireguard.py b/src/op_mode/wireguard.py
index 15bf63e81..e08bc983a 100755
--- a/src/op_mode/wireguard.py
+++ b/src/op_mode/wireguard.py
@@ -21,22 +21,17 @@ import shutil
 import syslog as sl
 import re
 
+from vyos.config import Config
 from vyos.ifconfig import WireGuardIf
-
+from vyos.util import cmd
+from vyos.util import run
+from vyos.util import check_kmod
 from vyos import ConfigError
-from vyos.config import Config
-from vyos.util import cmd, run
 
 dir = r'/config/auth/wireguard'
 psk = dir + '/preshared.key'
 
-def check_kmod():
-    """ check if kmod is loaded, if not load it """
-    if not os.path.exists('/sys/module/wireguard'):
-        sl.syslog(sl.LOG_NOTICE, "loading wirguard kmod")
-        if run('sudo modprobe wireguard') != 0:
-            sl.syslog(sl.LOG_ERR, "modprobe wireguard failed")
-            raise ConfigError("modprobe wireguard failed")
+k_mod = 'wireguard'
 
 def generate_keypair(pk, pub):
     """ generates a keypair which is stored in /config/auth/wireguard """
@@ -106,7 +101,7 @@ def del_key_dir(kname):
 
 
 if __name__ == '__main__':
-    check_kmod()
+    check_kmod(k_mod)
     parser = argparse.ArgumentParser(description='wireguard key management')
     parser.add_argument(
         '--genkey', action="store_true", help='generate key-pair')