vyos-netlinkd: T8781: do not call commit_in_progress() for EVERY netlink message (#5199)

* vyos-netlinkd: T8781: do not call commit_in_progress() for EVERY netlink message

Signed-off-by: Fabrizzio Petrucci <fabrizziopm@compumundohipermegared.one>

* vyos-netlinkd: T8781: restrict netlink subscription to link multicast group

Bind IPRoute with RTMGRP_LINK only so route/rule/neighbour/address updates
(e.g. full-table BGP) are not delivered to this socket.

Add a match wildcard so unexpected message types do not raise MatchError and
get logged as generic errors.

---------

Signed-off-by: Fabrizzio Petrucci <fabrizziopm@compumundohipermegared.one>
Co-authored-by: Fabrizzio Petrucci <fabrizziopm@compumundohipermegared.one>

1 files changed, 14 insertions, 5 deletions

diff --git a/src/services/vyos-netlinkd b/src/services/vyos-netlinkd
index 7bf6b8cce..368824bf9 100755
--- a/src/services/vyos-netlinkd
+++ b/src/services/vyos-netlinkd
@@ -22,6 +22,7 @@ import select
 
 from pyroute2 import IPRoute # pylint: disable = no-name-in-module
 from pyroute2 import NetlinkError # pylint: disable = no-name-in-module
+from pyroute2.netlink.rtnl import RTMGRP_LINK
 from time import sleep
 from typing import Optional
 
@@ -105,7 +106,8 @@ def main():
                    facility=syslog.LOG_DAEMON)
     syslog.syslog(syslog.LOG_INFO, "VyOS Netlink listener daemon started.")
 
-    ipr = IPRoute()
+    # Subscribe to link notifications only (not routes/rules/neigh/addr/...).
+    ipr = IPRoute(groups=RTMGRP_LINK)
     ipr.bind()
     fd = ipr.fileno()
 
@@ -123,12 +125,17 @@ def main():
                 # timeout - retry
                 continue
 
+            # Check if a config commit is in progress before processing any
+            # messages. This avoids blocking per-message and reduces unnecessary
+            # commit_in_progress() calls.
+            if commit_in_progress():
+                syslog.syslog(syslog.LOG_DEBUG,
+                              'Config commit in progress, skipping netlink events')
+                sleep(1)
+                continue
+
             # Receive and process any messages
             for message in ipr.get():
-                # Wait for commit to complete
-                while commit_in_progress():
-                    sleep(0.250)
-
                 # Parse NETLINK message
                 match message['event']:
                     # Message received during interface creation or modification
@@ -153,6 +160,8 @@ def main():
                     # Deletion of a network link which has been previously added to the kernel
                     case 'RTM_DELLINK':
                         pass
+                    case _:
+                        pass
 
         except NetlinkError as e:
             syslog.syslog(syslog.LOG_ERR, f'Netlink error: {e}')