Add a new open vswitch plugin

This plugin allows to add, delete and dump openflow rules for a given
bridge.

Signed-off-by: Guillaume <[email protected]>

Author: gthvn1

Diff for: README.md

@@ -338,6 +338,77 @@ Restart a service only if it is already running.
 $ xe host-call-plugin host-uuid<uuid> plugin=service.py fn=try_restart_service args:service=<service>
 ```
 
+
+### `open-vswitch`
+
+Add, delete and dump openflow rules.
+
+#### Examples
+
+##### Add flow
+
+```
+$ xe host-call-plugin host-uuid<uuid> plugin=open-vswitch.py \
+  fn=add-flow \
+  args:bridge=xenbr0 \
+  args:rule="ip,in_port=1,dl_src=5e:f3:5b:e6:7b:f3,nw_dst=10.10.10.0/24 actions=drop"
+```
+
+##### Delete flows
+```
+$ xe host-call-plugin host-uuid<uuid> plugin=open-vswitch.py \
+  fn=del-flows \
+  args:bridge=xenbr0 \
+  args:rule="ip,in_port=1,dl_src=5e:f3:5b:e6:7b:f3,nw_dst=10.10.10.0/24"
+```
+
+##### Dump flows
+
+- This command will return all flows entries in the bridge passed as a parameter.
+- That means a bridge is required as parameter:
+```
+$ xe host-call-plugin host-uuid=<uuid> plugin=open-vswitch.py fn=dump-flows args:bridge=xenbr0 | jq .
+{
+  "returncode": 0,
+  "command": [
+    "ovs-ofctl",
+    "dump-flows",
+    "xenbr0"
+  ],
+  "stderr": "",
+  "stdout": "NXST_FLOW reply (xid=0x4):\n cookie=0x0, duration=248977.339s, table=0, n_packets=24591786, n_bytes=3278442075, idle_age=0, hard_age=65534, priority=0 actions=NORMAL\n"
+}
+```
+
+- This error is raised when the bridge parameter is missing:
+```
+$ xe host-call-plugin host-uuid=<uuid> plugin=open-vswitch.py fn=dump-flows | jq .
+{
+  "returncode": 1,
+  "command": [
+    "ovs-ofctl",
+    "dump-flows"
+  ],
+  "stderr": "bridge parameter is missing",
+  "stdout": ""
+}
+```
+
+- If the bridge is unknown, the following error will occur:
+```
+$ xe host-call-plugin host-uuid=<uuid> plugin=open-vswitch.py args:bridge=xenbr10 fn=dump-flows | jq .
+{
+  "returncode": 1,
+  "command": [
+    "ovs-ofctl",
+    "dump-flows",
+    "xenbr10"
+  ],
+  "stderr": "ovs-ofctl: xenbr10 is not a bridge or a socket\n",
+  "stdout": ""
+}
+```
+
 ## Tests
 
 To run the plugins' unit tests you'll need to install `pytest`, `pyfakefs` and `mock`.

Diff for: SOURCES/etc/xapi.d/plugins/open-vswitch.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import json
+
+import XenAPIPlugin
+
+from xcpngutils import configure_logging, error_wrapped, run_command
+
+
+@error_wrapped
+def add_flow(_session, args):
+    _LOGGER.info("Calling add_flow with args {}".format(args))
+    return json.dumps(True)
+
+
+@error_wrapped
+def del_flows(_session, args):
+    _LOGGER.info("Calling del_flows with args {}".format(args))
+    return json.dumps(True)
+
+
+@error_wrapped
+def dump_flows(_session, args):
+    _LOGGER.info("Calling check with args {}".format(args))
+    ofctl_cmd = ["ovs-ofctl", "dump-flows"]
+    bridge = args.get("bridge")
+
+    if bridge is None:
+        return json.dumps(
+            {
+                "returncode": 1,
+                "command": ofctl_cmd,
+                "stderr": "bridge parameter is missing",
+                "stdout": "",
+            }
+        )
+    ofctl_cmd.append(bridge)
+    cmd = run_command(ofctl_cmd, check=False)
+    return json.dumps(cmd)
+
+
+_LOGGER = configure_logging("open-vswitch")
+if __name__ == "__main__":
+    XenAPIPlugin.dispatch(
+        {
+            "add-flow": add_flow,
+            "del-flows": del_flows,
+            "dump-flows": dump_flows,
+        }
+    )