[ycabled] add secure channel support for grpc dualtor active-active c…

…onnectivity (sonic-net#275)

Signed-off-by: vaibhav-dahiya vdahiya@microsoft.com
This PR adds support for creating a secure channel for gRPC between SOC and SONiC.
the certs and configurations are defined in config DB

config': {
            'type': 'secure',
            'auth_level': 'server',
            'log_level': 'info'
        },
        'certs': {
            'client_crt': path',
            'client_key': 'path
            'ca_crt': 'path,
            'grpc_ssl_credential': 'target override'
        }
Using this config parameter we can have secure/insecure as well as mutual/server level authentication between SoC and SONiC.
This PR leverages the cert API's in gRPC lib and certs created to create a TLS based handshake if required to setup gRPC channel

Description
Motivation and Context
Required for secure gRPC support between SONiC and SoC

How Has This Been Tested?
Unit-Tests and running the changes on the testbed

sonic-ycabled/tests/test_y_cable_helper.py

@@ -4959,7 +4959,10 @@ def test_check_identifier_presence_and_setup_channel_with_mock_not_none(self):
     @patch('proto_out.linkmgr_grpc_driver_pb2_grpc.DualToRActiveStub', MagicMock(return_value=True))
     def test_setup_grpc_channel_for_port(self):
 
-        rc = setup_grpc_channel_for_port("Ethernet0", "192.168.0.1")
+        with patch('ycable.ycable_utilities.y_cable_helper.y_cable_platform_sfputil') as patched_util:
+
+            patched_util.get_asic_id_for_logical_port.return_value = 0
+            rc = setup_grpc_channel_for_port("Ethernet0", "192.168.0.1")
 
         assert(rc == (None, None))
 
@@ -5306,4 +5309,25 @@ def test_get_mux_cable_static_info_without_presence(self):
         assert(rc['nic_lane1_postcursor1'] == 'N/A')
         assert(rc['nic_lane1_postcursor2'] == 'N/A')
 
+    def test_get_grpc_credentials(self):
+
+        kvp = {}
+        type = None
+
+        rc = get_grpc_credentials(type, kvp)
+
+        assert(rc == None)
+
+
+    @patch('builtins.open')
+    def test_get_grpc_credentials_root(self, open):
+
+        kvp = {"ca_crt": "file"}
+        type = "server" 
+
+        mock_file = MagicMock()
+        mock_file.read = MagicMock(return_value=bytes('abcdefgh', 'utf-8'))
+        open.return_value = mock_file
+        rc = get_grpc_credentials(type, kvp)
 
+        assert(rc != None)

sonic-ycabled/ycable/ycable_utilities/y_cable_helper.py

@@ -56,6 +56,13 @@
 # port id 0 -> maps to  T0
 # port id 1 -> maps to  LT0
 
+GRPC_CLIENT_OPTIONS = [
+    ('grpc.keepalive_timeout_ms', 8000),
+    ('grpc.keepalive_time_ms', 4000),
+    ('grpc.keepalive_permit_without_calls', True),
+    ('grpc.http2.max_pings_without_data', 0)
+]
+
 SYSLOG_IDENTIFIER = "y_cable_helper"
 
 helper_logger = logger.Logger(SYSLOG_IDENTIFIER)
@@ -360,13 +367,78 @@ def retry_setup_grpc_channel_for_port(port, asic_index):
                 grpc_port_stubs[port] = stub
                 return True
 
+
+def get_grpc_credentials(type, kvp):
+
+    root_file = kvp.get("ca_crt", None)
+    if root_file is not None: 
+        root_cert = open(root_file, 'rb').read()
+    else:
+        helper_logger.log_error("grpc credential channel setup no root file in config_db")
+        return None
+
+    if type == "mutual":
+        cert_file = kvp.get("client_crt", None)
+        if cert_file is not None: 
+            cert_chain = open(cert_file, 'rb').read()
+        else:
+            helper_logger.log_error("grpc credential channel setup no cert file for mutual authentication in config_db")
+            return None
+
+        key_file = kvp.get("client_key", None)
+        if key_file is not None: 
+            key = open(key_file, 'rb').read()
+        else:
+            helper_logger.log_error("grpc credential channel setup no key file for mutual authentication in config_db")
+            return None
+
+        credential = grpc.ssl_channel_credentials(
+                root_certificates=root_cert,
+                private_key=key,
+                certificate_chain=cert_chain)
+    elif type == "server":
+        credential = grpc.ssl_channel_credentials(
+                root_certificates=root_cert)
+    else:
+        #should not happen
+        helper_logger.log_error("grpc credential channel setup no type specified for authentication in config_db")
+        return None
+
+    return credential
+
+def create_channel(type,level, kvp, soc_ip):
+
+    retries = 3
+    for _ in range(retries):
+
+        if type == "secure": 
+            credential = get_grpc_credentials(level, kvp)
+            target_name = kvp.get("grpc_ssl_credential", None)
+            if credential is None or target_name is None:
+                return (None, None)
+
+            GRPC_CLIENT_OPTIONS.append(('grpc.ssl_target_name_override', '{}'.format(target_name)))
+
+            channel = grpc.secure_channel("{}:{}".format(soc_ip, GRPC_PORT), credential, options=GRPC_CLIENT_OPTIONS)
+        else:
+            channel = grpc.insecure_channel("{}:{}".format(soc_ip, GRPC_PORT), options=GRPC_CLIENT_OPTIONS)
+
+        stub = linkmgr_grpc_driver_pb2_grpc.DualToRActiveStub(channel)
+
+        channel_ready = grpc.channel_ready_future(channel)
+
+        try:
+            channel_ready.result(timeout=2)
+        except grpc.FutureTimeoutError:
+            channel = None
+            stub = None
+        else:
+            break
+
+    return channel, stub
+
 def setup_grpc_channel_for_port(port, soc_ip):
-    """
-    root_cert = open('/etc/sonic/credentials/ca-chain-bundle.cert.pem', 'rb').read()
-    key = open('/etc/sonic/credentials/client.key.pem', 'rb').read()
-    cert_chain = open('/etc/sonic/credentials/client.cert.pem', 'rb').read()
 
-    """
     """
     Dummy values for lab for now
     TODO remove these once done
@@ -381,23 +453,41 @@ def setup_grpc_channel_for_port(port, soc_ip):
     """
     helper_logger.log_notice("Setting up gRPC channel for RPC's {} {}".format(port,soc_ip))
 
-    retries = 3
-    for _ in range(retries):
-        channel = grpc.insecure_channel("{}:{}".format(soc_ip, GRPC_PORT), options=[('grpc.keepalive_timeout_ms', 8000),
-                                                                                    ('grpc.keepalive_time_ms', 4000),
-                                                                                    ('grpc.keepalive_permit_without_calls', True),
-                                                                                    ('grpc.http2.max_pings_without_data', 0)])
-        stub = linkmgr_grpc_driver_pb2_grpc.DualToRActiveStub(channel)
+    config_db,grpc_config = {}, {}
+    namespaces = multi_asic.get_front_end_namespaces()
+    for namespace in namespaces:
+        asic_id = multi_asic.get_asic_index_from_namespace(namespace)
+        config_db[asic_id] = daemon_base.db_connect("CONFIG_DB", namespace)
+        grpc_config[asic_id] = swsscommon.Table(config_db[asic_id], "GRPCCLIENT")
 
-        channel_ready = grpc.channel_ready_future(channel)
+    asic_index = y_cable_platform_sfputil.get_asic_id_for_logical_port(port)
 
-        try:
-            channel_ready.result(timeout=2)
-        except grpc.FutureTimeoutError:
-            channel = None
-            stub = None
-        else:
-            break
+    #if no config from config DB, treat channel to be as insecure
+    type = "insecure"
+    level = "server"
+
+    (status, fvs) = grpc_config[asic_index].get("config")
+    if status is False:
+        helper_logger.log_warning(
+            "Could not retreive fieldvalue pairs for {}, inside config_db table kvp config for {} for setting up channel type".format(port, grpc_config[asic_index].getTableName()))
+    else:
+        grpc_config_dict = dict(fvs)
+        type = grpc_config_dict.get("type", None)
+        level = grpc_config_dict.get("auth_level", None)
+
+
+    kvp = {}
+    if type == "secure":
+        (status, fvs) = grpc_config[asic_index].get("certs")
+        if status is False:
+            helper_logger.log_warning(
+                "Could not retreive fieldvalue pairs for {}, inside config_db table kvp certs for {} for setting up channel type".format(port, grpc_config[asic_index].getTableName()))
+            #if type is secure, must have certs defined
+            return (None, None)
+        kvp = dict(fvs)
+
+
+    channel, stub = create_channel(type, level, kvp, soc_ip) 
 
     if stub is None:
         helper_logger.log_warning("stub was not setup for gRPC soc ip {} port {}, no gRPC soc server running ?".format(soc_ip, port))