[storage_backend] Add backend acl service (#14229) (#14281)

files/build_templates/sonic_debian_extension.j2

@@ -586,6 +586,11 @@ sudo cp $IMAGE_CONFIGS/config-chassisdb/config-chassisdb $FILESYSTEM_ROOT/usr/bi
 echo "config-chassisdb.service" | sudo tee -a $GENERATED_SERVICE_FILE
 sudo LANG=C chroot $FILESYSTEM_ROOT systemctl enable config-chassisdb.service
 
+# Copy backend-acl script and service file
+sudo cp $IMAGE_CONFIGS/backend_acl/backend-acl.service $FILESYSTEM_ROOT_USR_LIB_SYSTEMD_SYSTEM/backend-acl.service
+sudo cp $IMAGE_CONFIGS/backend_acl/backend_acl.py $FILESYSTEM_ROOT/usr/bin/backend_acl.py
+echo "backend-acl.service" | sudo tee -a $GENERATED_SERVICE_FILE
+
 # Copy SNMP configuration files
 sudo cp $IMAGE_CONFIGS/snmp/snmp.yml $FILESYSTEM_ROOT/etc/sonic/
 

files/image_config/backend_acl/backend-acl.service

@@ -0,0 +1,12 @@
+[Unit]
+Description=Enable backend acl on storage backend ToRs
+After=swss.service
+BindsTo=sonic.target
+After=sonic.target
+
+[Service]
+Type=oneshot
+ExecStart=/usr/bin/backend_acl.py
+
+[Install]
+WantedBy=sonic.target

files/image_config/backend_acl/backend_acl.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python
+
+import os
+import subprocess
+import syslog
+import time
+
+from swsscommon.swsscommon import SonicV2Connector
+
+SYSLOG_IDENTIFIER = os.path.basename(__file__)
+
+SONIC_CFGGEN_PATH = '/usr/local/bin/sonic-cfggen'
+
+def log_info(msg):
+    syslog.openlog(SYSLOG_IDENTIFIER)
+    syslog.syslog(syslog.LOG_INFO, msg)
+    syslog.closelog()
+
+def run_command(cmd, return_cmd=False):
+   log_info("executing cmd =  {}".format(cmd))
+   proc = subprocess.Popen(cmd, shell=False, stdout=subprocess.PIPE)
+   out, err = proc.communicate()
+   if return_cmd:
+       if err:
+           return "Unknown"
+
+       if len(out) > 0:
+           return out.strip().decode('utf-8')
+
+def _get_device_type():
+    """
+    Get device type
+    """
+    device_type = run_command([SONIC_CFGGEN_PATH, '-m', '-v', 'DEVICE_METADATA.localhost.type'], return_cmd=True)
+    return device_type
+
+def _is_storage_device():
+    """
+    Check if the device is a storage device or not
+    """
+    storage_device = run_command([SONIC_CFGGEN_PATH, '-d', '-v', 'DEVICE_METADATA.localhost.storage_device'], return_cmd=True)
+    return storage_device == "true"
+
+def _is_acl_table_present():
+    """
+    Check if acl table exists
+    """
+    acl_table = run_command([SONIC_CFGGEN_PATH, '-d', '-v', 'ACL_TABLE.DATAACL'], return_cmd=True)
+    return (acl_table != "Unknown" and bool(acl_table))
+
+def _is_switch_table_present():
+    state_db = SonicV2Connector(host='127.0.0.1')
+    state_db.connect(state_db.STATE_DB, False)
+    table_present = False
+    wait_time = 0
+    TIMEOUT = 120
+    STEP = 10
+
+    while wait_time < TIMEOUT:
+        if state_db.exists(state_db.STATE_DB, 'SWITCH_CAPABILITY|switch'):
+            table_present = True
+            break
+        time.sleep(STEP)
+        wait_time += STEP
+    if not table_present:
+        log_info("Switch table not present")
+    return table_present
+
+def load_backend_acl(device_type):
+    """
+    Load acl on backend storage device
+    """
+    BACKEND_ACL_TEMPLATE_FILE = os.path.join('/', "usr", "share", "sonic", "templates", "backend_acl.j2")
+    BACKEND_ACL_FILE = os.path.join('/', "etc", "sonic", "backend_acl.json")
+
+    # this acl needs to be loaded only on a storage backend ToR. acl load will fail if the switch table isn't present
+    if _is_storage_device() and _is_acl_table_present() and _is_switch_table_present():
+        if os.path.isfile(BACKEND_ACL_TEMPLATE_FILE):
+            run_command(['sudo', SONIC_CFGGEN_PATH, '-d', '-t', '{},{}'.format(BACKEND_ACL_TEMPLATE_FILE, BACKEND_ACL_FILE)])
+        if os.path.isfile(BACKEND_ACL_FILE):
+            run_command(['acl-loader', 'update', 'incremental', BACKEND_ACL_FILE])
+    else:
+        log_info("Skipping backend acl load - conditions not met")
+
+def main():
+    device_type = _get_device_type()
+    if device_type != "BackEndToRRouter":
+        log_info("Skipping backend acl load on unsupported device type: {}".format(device_type))
+        return
+
+    load_backend_acl(device_type)
+
+if __name__ == "__main__":
+    main()