Datapath Probe Cli and Document (#5554)

Signed-off-by: Saurabh Mehra <saurabhmehra@fb.com>

docs/docusaurus/sidebars.json

@@ -108,7 +108,8 @@
       "howtos/header_enrichment.md"
     ],
     "Debugging Tools": [
-      "debugging_tools/show_tech"
+      "debugging_tools/show_tech",
+      "debugging_tools/dp_probe_cli"
     ],
     "Federation Gateway": [
       {

docs/readmes/debugging_tools/dp_probe_cli.md

@@ -0,0 +1,47 @@
+---
+id: dp_probe_cli
+title: Data Path Probe Cli Command
+hide_title: true
+---
+# dp_probe_cli
+
+## Overview:
+
+This command helps an operator to probe the Datapath to the UE.
+
+
+### Usage
+
+```
+# On your GW host, run the following command
+$ dp_probe_cli.py -i <IMSI>
+$ dp_probe_cli.py -i 1010000051011
+IMSI: 1010000051011, IP: 192.168.128.15
+Running: sudo ovs-appctl ofproto/trace gtp_br0 tcp,in_port=local,ip_dst=192.168.128.15,ip_src=8.8.8.8,tcp_src=80,tcp_dst=3372
+Datapath Actions: set(tunnel(tun_id=0x1000308,dst=10.0.2.240,ttl=64,tp_dst=2152,flags(df|key))),pop_eth,2
+
+# You can also supply the followin options
+# -I <External IP Address>
+# -P <External Port>
+# -UP <UE Port>
+# -p <Protocol tcp/udp/icmp>
+
+$ dp_probe_cli.py -i 1010000051016 -I 4.2.2.2 -p tcp -P 8080 -UP 3172
+IMSI: 1010000051016, IP: 192.168.128.14
+Running: sudo ovs-appctl ofproto/trace gtp_br0 tcp,in_port=local,ip_dst=192.168.128.14,ip_src=4.2.2.2,tcp_src=8080,tcp_dst=3172
+Datapath Actions: set(tunnel(tun_id=0x1000208,dst=10.0.2.240,ttl=64,tp_dst=2152,flags(df|key))),pop_eth,2
+
+```
+
+
+
+### What is this command doing?
+
+This command is a wrapper around *ovs-appctl ofproto/trace* which simulates the Datapath of the packet.
+
+
+### How to read the Output?
+
+Based on the *IMSI* supplied to this command:
+- If the UE is not connected, the command will output ***UE is not connected***
+- If the UE is connected, it prints the *IP Address* of the UE and the Datapath Actions based on the ovs-appctl ofproto/trace

lte/gateway/python/scripts/dp_probe_cli.py

@@ -0,0 +1,140 @@
+#!/usr/bin/env python3
+
+"""
+Copyright 2020 The Magma Authors.
+
+This source code is licensed under the BSD-style license found in the
+LICENSE file in the root directory of this source tree.
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+import argparse
+import re
+import subprocess
+
+from lte.protos.mconfig import mconfigs_pb2
+from magma.common.service import MagmaService
+
+def create_parser():
+    """
+    Creates the argparse parser with all the arguments.
+    """
+    parser = argparse.ArgumentParser(
+        description="CLI wrapper around ovs-appctl ofproto/trace.\n"
+        "To display the Datapath actions of the supplied IMSI",
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+    )
+    parser.add_argument("-i", "--imsi", help="IMSI of the subscriber")
+    parser.add_argument("-I", "--ip", help="External IP")
+    parser.add_argument("-P", "--port", help="External Port")
+    parser.add_argument("-UP", "--ue_port", help="UE Port")
+    parser.add_argument("-p", "--protocol", help="Portocol (i.e. tcp, udp, icmp)")
+
+    return parser
+
+
+def find_ue_ip(imsi: str):
+    """
+    Finds the UE IP address corresponding to the IMSI
+    """
+    cmd = ["mobility_cli.py", "get_subscriber_table"]
+    output = subprocess.check_output(cmd)
+    output_str = str(output, "utf-8").strip()
+    pattern = "IMSI.*?" + imsi + ".*?([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})"
+    match = re.search(pattern, output_str)
+    if match:
+        return match.group(1)
+    else:
+        return "NA"
+
+
+def output_datapath_actions(
+    ue_ip: str, external_ip: str, external_port: str, ue_port: str, protocol: str
+):
+    """
+    Returns the Output of Datapath Actions based as per the supplied UE IP
+    """
+    service = MagmaService("pipelined", mconfigs_pb2.PipelineD())
+    if service.mconfig.nat_enabled:
+        in_port = "local"
+    else:
+        in_port = "patch-up"
+
+    cmd = ["sudo", "ovs-appctl", "ofproto/trace", "gtp_br0"]
+
+    cmd_append = (
+        protocol + ",in_port=" + in_port + ",ip_dst=" + ue_ip + ",ip_src=" + external_ip
+    )
+
+    if protocol != "icmp":
+        cmd_append += (
+            ","
+            + protocol
+            + "_src="
+            + external_port
+            + ","
+            + protocol
+            + "_dst="
+            + ue_port
+        )
+
+    cmd.append(cmd_append)
+
+    print("Running: " + " ".join(cmd))
+    output = subprocess.check_output(cmd)
+    output_str = str(output, "utf-8").strip()
+    pattern = "Datapath\sactions:(.*)"
+    match = re.search(pattern, output_str)
+    if match:
+        return match.group(1).strip()
+    else:
+        return "NA"
+
+
+def get_options(args):
+    external_ip = args.ip if args.ip else "8.8.8.8"
+    external_port = args.port if args.port else "80"
+    ue_port = args.ue_port if args.ue_port else "3372"
+    protocol = args.protocol if args.protocol else "tcp"
+
+    return {
+        "external_ip": external_ip,
+        "external_port": external_port,
+        "ue_port": ue_port,
+        "protocol": protocol,
+    }
+
+
+def main():
+    parser = create_parser()
+    # Parse the args
+    args = parser.parse_args()
+    if not args.imsi:
+        parser.print_usage()
+        exit(1)
+    ue_ip = find_ue_ip(args.imsi)
+    if ue_ip == "NA":
+        print("UE is not connected")
+        exit(1)
+
+    print("IMSI: " + args.imsi + ", IP: " + ue_ip)
+
+    input_options = get_options(args)
+    dp_actions = output_datapath_actions(
+        ue_ip,
+        input_options["external_ip"],
+        input_options["external_port"],
+        input_options["ue_port"],
+        input_options["protocol"],
+    )
+
+    print("Datapath Actions: " + dp_actions)
+
+
+if __name__ == "__main__":
+    main()