[RFC4292][Namespace]: Fix implementation of RouteUpdater for multi-asic platform (sonic-net#176)

* [RFC4292][Namespace]: Fix implementation of RouteUpdater for multi-asic platform.
For multi-asic platforms, the default route was getting retrieved from only
the last namespace as the result dictionary was being written with the same key.
To avoid this, modify implementation to retrieve default routes from all
front end asic namespaces.Update implementation to ensure that only
external routes are displayed in the result.
Add test case to test multiple namespaces.

Author: SuvarnaMeenakshi

src/sonic_ax_impl/mibs/ietf/rfc4292.py

@@ -5,6 +5,7 @@
 from ax_interface import MIBMeta, ValueType, MIBUpdater, SubtreeMIBEntry
 from ax_interface.util import ip2tuple_v4
 from bisect import bisect_right
+from sonic_py_common import multi_asic
 
 class RouteUpdater(MIBUpdater):
     def __init__(self):
@@ -49,26 +50,41 @@ def update_data(self):
             self.route_dest_list.append(sub_id)
             self.route_dest_map[sub_id] = self.loips[loip].packed
 
-        route_entries = Namespace.dbs_keys(self.db_conn, mibs.APPL_DB, "ROUTE_TABLE:*")
-        if not route_entries:
-            return
-
-        for route_entry in route_entries:
-            routestr = route_entry
-            ipnstr = routestr[len("ROUTE_TABLE:"):]
-            if ipnstr == "0.0.0.0/0":
-                ipn = ipaddress.ip_network(ipnstr)
-                ent = Namespace.dbs_get_all(self.db_conn, mibs.APPL_DB, routestr, blocking=True)
-                nexthops = ent["nexthop"]
-                ifnames = ent["ifname"]
-                for nh, ifn in zip(nexthops.split(','), ifnames.split(',')):
-                    ## Ignore non front panel interfaces
-                    ## TODO: non front panel interfaces should not be in APPL_DB at very beginning
-                    ## This is to workaround the bug in current sonic-swss implementation
-                    if ifn == "eth0" or ifn == "lo" or ifn == "docker0": continue
-                    sub_id = ip2tuple_v4(ipn.network_address) + ip2tuple_v4(ipn.netmask) + (self.tos,) + ip2tuple_v4(nh)
-                    self.route_dest_list.append(sub_id)
-                    self.route_dest_map[sub_id] = ipn.network_address.packed
+        # Get list of front end asic namespaces for multi-asic platform.
+        # This list will be empty for single asic platform.
+        front_ns = multi_asic.get_all_namespaces()['front_ns']
+        ipnstr = "0.0.0.0/0"
+        ipn = ipaddress.ip_network(ipnstr)
+        route_str = "ROUTE_TABLE:0.0.0.0/0"
+
+        for db_conn in Namespace.get_non_host_dbs(self.db_conn):
+            # For multi-asic platform, proceed to get routes only for 
+            # front end namespaces.
+            # For single-asic platform, front_ns will be empty list.
+            if front_ns and db_conn.namespace not in front_ns:
+                continue
+            port_table = multi_asic.get_port_table(db_conn.namespace)
+            ent = db_conn.get_all(mibs.APPL_DB, route_str, blocking=False)
+            if ent is None:
+                continue
+            nexthops = ent["nexthop"]
+            ifnames = ent["ifname"]
+            for nh, ifn in zip(nexthops.split(','), ifnames.split(',')):
+                ## Ignore non front panel interfaces
+                ## TODO: non front panel interfaces should not be in APPL_DB at very beginning
+                ## This is to workaround the bug in current sonic-swss implementation
+                if ifn == "eth0" or ifn == "lo" or ifn == "docker0":
+                    continue
+                # Ignore internal asic routes
+                if multi_asic.is_port_channel_internal(ifn, db_conn.namespace):
+                    continue
+                if (ifn in port_table and
+                   multi_asic.ROLE in port_table[ifn] and
+                   port_table[ifn][multi_asic.ROLE] == multi_asic.INTERNAL_PORT): 
+                    continue
+                sub_id = ip2tuple_v4(ipn.network_address) + ip2tuple_v4(ipn.netmask) + (self.tos,) + ip2tuple_v4(nh)
+                self.route_dest_list.append(sub_id)
+                self.route_dest_map[sub_id] = ipn.network_address.packed
 
         self.route_dest_list.sort()
 

tests/mock_tables/asic0/config_db.json

@@ -1,2 +1,41 @@
 {
+  "DEVICE_METADATA|localhost": {
+    "chassis_serial_number": "SAMPLETESTSN",
+    "sub_role": "FrontEnd"
+  },
+  "PORT_TABLE:Ethernet0": {
+    "description": "snowflake",
+    "alias": "etp1",
+    "role": "Ext",
+    "speed": 100000
+  },
+  "PORT_TABLE:Ethernet4": {
+    "description": "snowflake",
+    "alias": "etp2",
+    "role": "Ext",
+    "speed": 100000
+  },
+  "PORT_TABLE:Ethernet-BP0": {
+    "description": "snowflake",
+    "alias": "etp3",
+    "role": "Int",
+    "speed": 100000
+  },
+  "PORT_TABLE:Ethernet-BP4": {
+    "description": "snowflake",
+    "alias": "etp4",
+    "role": "Int",
+    "speed": 100000
+  },
+  "LAG_MEMBER_TABLE:PortChannel01:Ethernet-BP0": {
+    "status": "enabled"
+  },
+  "LAG_MEMBER_TABLE:PortChannel01:Ethernet-BP4": {
+    "status": "enabled"
+  },
+  "LAG_TABLE:PortChannel01": {
+    "admin_status": "up",
+    "oper_status": "up",
+    "mtu": "9216"
+  }
 }

tests/mock_tables/asic1/config_db.json

@@ -1,2 +1,38 @@
 {
+  "DEVICE_METADATA|localhost": {
+    "chassis_serial_number": "SAMPLETESTSN",
+    "sub_role": "FrontEnd"
+  },
+  "PORT_TABLE:Ethernet8": {
+    "description": "snowflake",
+    "alias": "etp5",
+    "role": "Ext",
+    "speed": 100000
+  },
+  "PORT_TABLE:Ethernet12": {
+    "speed": 1000,
+    "role": "Ext",
+    "alias": "etp6"
+  },
+  "PORT_TABLE:Ethernet-BP8": {
+    "role": "Int",
+    "alias": "etp7"
+  },
+  "PORT_TABLE:Ethernet-BP12": {
+    "description": "snowflake",
+    "role": "Int",
+    "alias": "etp8",
+    "speed": 1000
+  },
+  "LAG_MEMBER_TABLE:PortChannel02:Ethernet-BP08": {
+    "status": "enabled"
+  },
+  "LAG_MEMBER_TABLE:PortChannel02:Ethernet-BP12": {
+    "status": "enabled"
+  },
+  "LAG_TABLE:PortChannel02": {
+    "admin_status": "up",
+    "oper_status": "up",
+    "mtu": "9216"
+  }
 }

tests/mock_tables/asic2/appl_db.json

@@ -36,6 +36,10 @@
     "nexthop": "",
     "ifname": "lo"
   },
+  "ROUTE_TABLE:0.0.0.0/0": {
+    "ifname": "PortChannel03,PortChannel04",
+    "nexthop": "10.10.0.0,10.10.0.5"
+  },
   "LAG_MEMBER_TABLE:PortChannel03:Ethernet-BP16": {
     "status": "enabled"
   },

tests/mock_tables/asic2/config_db.json

@@ -1,2 +1,53 @@
 {
+  "DEVICE_METADATA|localhost": {
+    "chassis_serial_number": "SAMPLETESTSN",
+    "sub_role": "BackEnd"
+  },
+  "PORT_TABLE:Ethernet-BP16": {
+    "description": "backplane",
+    "alias": "etp9",
+    "speed": 100000
+  },
+  "PORT_TABLE:Ethernet-BP20": {
+    "description": "backplane",
+    "alias": "etp10",
+    "speed": 100000
+  },
+  "PORT_TABLE:Ethernet-BP24": {
+    "description": "backplane",
+    "alias": "etp11",
+    "speed": 100000
+  },
+  "PORT_TABLE:Ethernet-BP28": {
+    "description": "backplane",
+    "alias": "etp12",
+    "speed": 100000
+  },
+  "LAG_MEMBER_TABLE:PortChannel03:Ethernet-BP16": {
+    "status": "enabled"
+  },
+  "LAG_MEMBER_TABLE:PortChannel03:Ethernet-BP20": {
+    "status": "enabled"
+  },
+  "LAG_MEMBER_TABLE:PortChannel04:Ethernet-BP24": {
+    "status": "enabled"
+  },
+  "LAG_MEMBER_TABLE:PortChannel04:Ethernet-BP28": {
+    "status": "enabled"
+  },
+  "LAG_TABLE:PortChannel03": {
+    "admin_status": "up",
+    "oper_status": "up",
+    "mtu": "9216"
+  },
+  "LAG_TABLE:PortChannel04": {
+    "admin_status": "up",
+    "oper_status": "up",
+    "mtu": "9216"
+  },
+  "LAG_TABLE:PortChannel_Temp": {
+    "admin_status": "up",
+    "oper_status": "up",
+    "mtu": "9216"
+  }
 }

tests/mock_tables/multi_asic.py

@@ -0,0 +1,56 @@
+import os
+import json
+
+import tests.mock_tables.dbconnector
+from sonic_py_common import multi_asic
+from swsssdk import SonicDBConfig
+
+INPUT_DIR = os.path.dirname(os.path.abspath(__file__))
+int_port_channel = ['PortChannel01', 'PortChannel02', 'PortChannel03', 'PortChannel04']
+
+def mock_get_num_asics():
+    ns_list = SonicDBConfig.get_ns_list()
+    if len(ns_list) > 1:
+        return(len(ns_list) - 1)
+    else:
+        return 1
+
+
+def mock_is_multi_asic():
+    if mock_get_num_asics() > 1:
+        return True
+    else:
+        return False
+
+def mock_get_all_namespaces():
+   if mock_get_num_asics() == 1:
+       return {'front_ns': [], 'back_ns': []}
+   else:
+       return {'front_ns': ['asic0', 'asic1'], 'back_ns': ['asic2']}
+
+def mock_is_port_channel_internal(port_channel, namespace=None):
+    if (mock_get_num_asics() == 1):
+        return False
+    else:
+        return True if port_channel in int_port_channel else False
+
+def mock_get_port_table(namespace=None):
+    if namespace is not None:
+        fname = os.path.join(INPUT_DIR, namespace, 'config_db.json')
+    else:
+        fname = os.path.join(INPUT_DIR, 'config_db.json')
+    port_table = {}
+    db = {}
+    with open(fname) as f:
+        db = json.load(f)
+    for k in db:
+        if 'PORT_TABLE' in db:
+            new_key = k[len('PORT_TABLE:'):]
+            port_table[new_key] = db[k]
+    return port_table
+
+multi_asic.get_num_asics = mock_get_num_asics
+multi_asic.is_multi_asic = mock_is_multi_asic
+multi_asic.get_all_namespaces = mock_get_all_namespaces
+multi_asic.is_port_channel_internal = mock_is_port_channel_internal
+multi_asic.get_port_table = mock_get_port_table