Remove update of mgmt oper status in swss

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**What I did**
Issue to be fix: Currently operational status of mgmt interface is not present or correct for multi-asic devices.

**Why I did it**
Initial PR that added mgmt oper status feature in swss: sonic-net/sonic-swss#630
sonic-net/sonic-buildimage#21245 adds a script to update oper status of management interface periodically. In doing so, we no longer need to update oper status of mgmt interface in swss.

**How I verified it**
Verified on single-asic platform
1. verified on single-asic platform and multi-asic Chassis platfrom.
Single ASIC Arista device verification along with sonic-net/sonic-buildimage#21245 changes
Ran the below bash script to verify the state of STATE_DB: MGMT_OPER_STATUS table and also execute config_reload, verify if STATE_DB is flushed out and repopulated after monit starts periodic script.
```
#!/bin/bash
CUR_STATUS=`sonic-db-cli STATE_DB hgetall "MGMT_PORT_TABLE|eth0"`
echo "current status in STATE_DB is $CUR_STATUS :: expected to have up state"
snmp_result=`docker exec snmp snmpwalk -v2c -c <comm> <IP> 1.3.6.1.2.1.2.2.1.8.10000`
echo "snmp result  before config reload 5min $snmp_result :: expected to have 1 in snmp result"
sudo config reload -y
CUR_STATUS=`sonic-db-cli STATE_DB hgetall "MGMT_PORT_TABLE|eth0"`
echo "current status in STATE_DB after config_reload is $CUR_STATUS :: expected to have empty"
# sleep for snmp to start
sleep 60
snmp_result=`docker exec snmp snmpwalk -v2c -c <comm> <IP> 1.3.6.1.2.1.2.2.1.8.10000`
echo "snmp result  after config reload $snmp_result :: expected to return error since STATE_DB is not yet populated"
# monit will populate mgmt oper status after each 5min cycle
sleep 240
CUR_STATUS=`sonic-db-cli STATE_DB hgetall "MGMT_PORT_TABLE|eth0"`
echo "current status in STATE_DB after config_reload after 5min $CUR_STATUS :: expected to have up state"
snmp_result=`docker exec snmp snmpwalk -v2c -c <comm> <IP> 1.3.6.1.2.1.2.2.1.8.10000`
echo "snmp result  after config reload after 5min $snmp_result :: expected to have 1 in snmp result"
```
Result of above script:
```
current status in STATE_DB is {'oper_status': 'up'} :: expected to have up state
snmp result  before config reload 5min iso.3.6.1.2.1.2.2.1.8.10000 = INTEGER: 1 :: expected to have 1 in snmp result
Acquired lock on /etc/sonic/reload.lock
Disabling container and routeCheck monitoring ...
Stopping SONiC target ...
Running command: /usr/local/bin/sonic-cfggen -j /etc/sonic/init_cfg.json -j /etc/sonic/config_db.json --write-to-db
Running command: /usr/local/bin/db_migrator.py -o migrate
Running command: /usr/local/bin/sonic-cfggen -d -y /etc/sonic/sonic_version.yml -t /usr/share/sonic/templates/sonic-environment.j2,/etc/sonic/sonic-environment
Restarting SONiC target ...
Enabling container and routeCheck monitoring ...
Reloading Monit configuration ...
Reinitializing monit daemon
Released lock on /etc/sonic/reload.lock
current status in STATE_DB after config_reload is {} :: expected to have empty
snmp result  after config reload iso.3.6.1.2.1.2.2.1.8.10000 = No Such Object available on this agent at this OID :: expected to return error since STATE_DB is not yet populated
current status in STATE_DB after config_reload after 5min {'oper_status': 'up'} :: expected to have up state
snmp result  after config reload after 5min iso.3.6.1.2.1.2.2.1.8.10000 = INTEGER: 1 :: expected to have 1 in snmp result
```

**Details if related**

Author: mssonicbld

portsyncd/linksync.cpp

@@ -27,7 +27,6 @@ using namespace swss;
 #define VLAN_DRV_NAME   "bridge"
 #define TEAM_DRV_NAME   "team"
 
-const string MGMT_PREFIX = "eth";
 const string INTFS_PREFIX = "Ethernet";
 const string LAG_PREFIX = "PortChannel";
 
@@ -38,57 +37,11 @@ extern string g_switchType;
 LinkSync::LinkSync(DBConnector *appl_db, DBConnector *state_db) :
     m_portTableProducer(appl_db, APP_PORT_TABLE_NAME),
     m_portTable(appl_db, APP_PORT_TABLE_NAME),
-    m_statePortTable(state_db, STATE_PORT_TABLE_NAME),
-    m_stateMgmtPortTable(state_db, STATE_MGMT_PORT_TABLE_NAME)
+    m_statePortTable(state_db, STATE_PORT_TABLE_NAME)
 {
     std::shared_ptr<struct if_nameindex> if_ni(if_nameindex(), if_freenameindex);
     struct if_nameindex *idx_p;
 
-    for (idx_p = if_ni.get();
-            idx_p != NULL && idx_p->if_index != 0 && idx_p->if_name != NULL;
-            idx_p++)
-    {
-        string key = idx_p->if_name;
-
-        /* Explicitly store management ports oper status into the state database.
-         * This piece of information is used by SNMP. */
-        if (!key.compare(0, MGMT_PREFIX.length(), MGMT_PREFIX))
-        {
-            ostringstream cmd;
-            string res;
-            cmd << "cat /sys/class/net/" << shellquote(key) << "/operstate";
-            try
-            {
-                EXEC_WITH_ERROR_THROW(cmd.str(), res);
-            }
-            catch (...)
-            {
-                SWSS_LOG_WARN("Failed to get %s oper status", key.c_str());
-                continue;
-            }
-
-            /* Remove the trailing newline */
-            if (res.length() >= 1 && res.at(res.length() - 1) == '\n')
-            {
-                res.erase(res.length() - 1);
-                /* The value of operstate will be either up or down */
-                if (res != "up" && res != "down")
-                {
-                    SWSS_LOG_WARN("Unknown %s oper status %s",
-                            key.c_str(), res.c_str());
-                }
-                FieldValueTuple fv("oper_status", res);
-                vector<FieldValueTuple> fvs;
-                fvs.push_back(fv);
-
-                m_stateMgmtPortTable.set(key, fvs);
-                SWSS_LOG_INFO("Store %s oper status %s to state DB",
-                        key.c_str(), res.c_str());
-            }
-            continue;
-        }
-    }
-
     if (!WarmStart::isWarmStart())
     {
         /* See the comments for g_portSet in portsyncd.cpp */
@@ -168,8 +121,7 @@ void LinkSync::onMsg(int nlmsg_type, struct nl_object *obj)
     string key = rtnl_link_get_name(link);
 
     if (key.compare(0, INTFS_PREFIX.length(), INTFS_PREFIX) &&
-        key.compare(0, LAG_PREFIX.length(), LAG_PREFIX) &&
-        key.compare(0, MGMT_PREFIX.length(), MGMT_PREFIX))
+        key.compare(0, LAG_PREFIX.length(), LAG_PREFIX))
     {
         return;
     }
@@ -197,17 +149,6 @@ void LinkSync::onMsg(int nlmsg_type, struct nl_object *obj)
                        nlmsg_type, key.c_str(), admin, oper, addrStr, ifindex, master);
     }
 
-    if (!key.compare(0, MGMT_PREFIX.length(), MGMT_PREFIX))
-    {
-        FieldValueTuple fv("oper_status", oper ? "up" : "down");
-        vector<FieldValueTuple> fvs;
-        fvs.push_back(fv);
-        m_stateMgmtPortTable.set(key, fvs);
-        SWSS_LOG_INFO("Store %s oper status %s to state DB",
-                key.c_str(), oper ? "up" : "down");
-        return;
-    }
-
     /* teamd instances are dealt in teamsyncd */
     if (type && !strcmp(type, TEAM_DRV_NAME))
     {

portsyncd/linksync.h

@@ -20,7 +20,7 @@ class LinkSync : public NetMsg
 
 private:
     ProducerStateTable m_portTableProducer;
-    Table m_portTable, m_statePortTable, m_stateMgmtPortTable;
+    Table m_portTable, m_statePortTable;
 
     std::map<unsigned int, std::string> m_ifindexNameMap;
     std::map<unsigned int, std::string> m_ifindexOldNameMap;

tests/mock_tests/portsyncd/portsyncd_ut.cpp

@@ -187,18 +187,6 @@ namespace portsyncd_ut
 
 namespace portsyncd_ut
 {
-    TEST_F(PortSyncdTest, test_linkSyncInit)
-    {
-        if_ni_mock = populateNetDev();
-        mockCmdStdcout = "up\n";
-        swss::LinkSync sync(m_app_db.get(), m_state_db.get());
-        std::vector<std::string> keys;
-        sync.m_stateMgmtPortTable.getKeys(keys);
-        ASSERT_EQ(keys.size(), 1);
-        ASSERT_EQ(keys.back(), "eth0");
-        ASSERT_EQ(mockCallArgs.back(), "cat /sys/class/net/\"eth0\"/operstate");
-    }
-
     TEST_F(PortSyncdTest, test_cacheOldIfaces)
     {  
         if_ni_mock = populateNetDevAdvanced();
@@ -295,29 +283,6 @@ namespace portsyncd_ut
         ASSERT_EQ(sync.m_statePortTable.get("Ethernet0", ovalues), false);
     }
 
-    TEST_F(PortSyncdTest, test_onMsgMgmtIface){
-        swss::LinkSync sync(m_app_db.get(), m_state_db.get());
-        
-        /* Generate a netlink notification about the eth0 netdev iface */
-        std::vector<unsigned int> flags = {IFF_UP}; 
-        struct nl_object* msg = draft_nlmsg("eth0",
-                                            flags,
-                                            "",
-                                            "00:50:56:28:0e:4a",
-                                            16222,
-                                            9100,
-                                            0);
-        sync.onMsg(RTM_NEWLINK, msg);
-
-        /* Verify if the update has been written to State DB */
-        std::string oper_status;
-        ASSERT_EQ(sync.m_stateMgmtPortTable.hget("eth0", "oper_status", oper_status), true);
-        ASSERT_EQ(oper_status, "down");
-
-        /* Free Nl_object */
-        free_nlobj(msg);
-    }
-
     TEST_F(PortSyncdTest, test_onMsgIgnoreOldNetDev){
         if_ni_mock = populateNetDevAdvanced();
         swss::LinkSync sync(m_app_db.get(), m_state_db.get());