[LLDP] Fix for LLDP advertisements being sent with wrong information.

dockers/docker-lldp/lldpd.conf.j2

@@ -10,3 +10,5 @@ configure ports eth0 lldp portidsubtype local {{ mgmt_port_name }}
 configure system ip management pattern {{ ipv4 }}
 {% endif %}
 configure system hostname {{ DEVICE_METADATA['localhost']['hostname'] }}
+{# pause lldpd operations until all interfaces are well configured, resume command will run in lldpmgrd #}
+pause

dockers/docker-lldp/lldpmgrd

@@ -19,6 +19,9 @@ try:
     import subprocess
     import sys
 
+    import syslog
+    import os.path
+    import time
     from sonic_py_common import daemon_base
     from swsscommon import swsscommon
 except ImportError as err:
@@ -27,6 +30,7 @@ except ImportError as err:
 VERSION = "1.0"
 
 SYSLOG_IDENTIFIER = "lldpmgrd"
+PORT_INIT_TIMEOUT = 300
 
 
 class LldpManager(daemon_base.DaemonBase):
@@ -166,6 +170,13 @@ class LldpManager(daemon_base.DaemonBase):
         # Set select timeout to 10 seconds
         SELECT_TIMEOUT_MS = 1000 * 10
 
+        # Daemon is paused on the configuration file to avoid lldp packets with wrong information
+        # until all interfaces are well configured on lldpd
+        port_init_done = False
+        port_config_done = False
+        resume_lldp_sent = False
+        start_time = time.time()
+
         sel = swsscommon.Select()
 
         # Subscribe to PORT table notifications in the Config DB
@@ -204,9 +215,21 @@ class LldpManager(daemon_base.DaemonBase):
                             else:
                                 self.pending_cmds.pop(key, None)
 
+                elif key == "PortInitDone":
+                    port_init_done = True
+                elif key == "PortConfigDone":
+                    port_config_done = True
+
             # Process all pending commands
             self.process_pending_cmds()
 
+            # Resume the daemon since all interfaces data updated and configured to the lldpd so no miss leading packets will be sent
+            if port_init_done and port_config_done:
+                port_init_done = port_config_done = False
+                resume_lldpd(self)
+                resume_lldp_sent = True
+            if not resume_lldp_sent:
+                check_timeout(self, start_time)
 
 # ============================= Functions =============================
 
@@ -219,6 +242,18 @@ def main():
 
     lldpmgr.run()
 
+def resume_lldpd(self):
+    cmd = "lldpcli resume"
+    proc = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    (stdout, stderr) = proc.communicate()
+    if proc.returncode != 0:
+        self.log_error("Failed to resume lldpd with command: '{}': {}".format(cmd, stderr))
+        sys.exit(1)
+
+def check_timeout(self, start_time):
+    if time.time() - start_time > PORT_INIT_TIMEOUT:
+        self.log_error("Port init timeout reached ({} seconds), killing lldpmgrd...".format(PORT_INIT_TIMEOUT))
+        sys.exit(1)
 
 if __name__ == "__main__":
     main()

src/sonic-config-engine/tests/sample_output/py2/lldpd.conf

@@ -1,3 +1,4 @@
 configure ports eth0 lldp portidsubtype local eth0
 configure system ip management pattern 10.0.0.100
 configure system hostname switch-t0
+pause

src/sonic-config-engine/tests/sample_output/py3/lldpd.conf

@@ -1,3 +1,4 @@
 configure ports eth0 lldp portidsubtype local eth0
 configure system ip management pattern 10.0.0.100
 configure system hostname switch-t0
+pause