353: Netmask MIB enhancement

[ssithaia-ebay]

- What I did
Adding support of NETMASK MIB [ OID: 1.3.6.1.2.1.4.34.1.5.1] in snmp-subagent. This MIB returns the mapping between the assigned IP address and its network IP along with the netmask and IfIndex.

- How I did it
Updated rfc1213.py from snmp-subagent to accomodate NETMASK MIB implementation.

- How to verify it

Interface     Master   IPv4 address/mask  Admin/Oper  BGP Neighbor  Neighbor IP
-----------   -------  ------------------ ------------ ------------- -------------
Ethernet8               192.168.10.5/32     down/down   N/A           N/A
Ethernet56              192.168.11.5/32     down/down   N/A           N/A
Ethernet200             192.168.12.5/32     down/down   N/A           N/A
docker0                 240.127.1.1/24      up/down     N/A           N/A
eth0                    192.168.1.1/24      up/up       N/A           N/A

$ snmpwalk -v2c -c public 192.168.1.1 1.3.6.1.2.1.4.34.1.5.1

iso.3.6.1.2.1.4.34.1.5.1.4.192.168.1.1 = OID: iso.3.6.1.2.1.4.32.1.5.10000.1.4.192.168.1.0.24
iso.3.6.1.2.1.4.34.1.5.1.4.192.168.10.5 = OID: iso.3.6.1.2.1.4.32.1.5.9.1.4.192.168.10.5.32
iso.3.6.1.2.1.4.34.1.5.1.4.192.168.11.5 = OID: iso.3.6.1.2.1.4.32.1.5.57.1.4.192.168.11.5.32
iso.3.6.1.2.1.4.34.1.5.1.4.192.168.12.5 = OID: iso.3.6.1.2.1.4.32.1.5.201.1.4.192.168.12.5.32
iso.3.6.1.2.1.4.34.1.5.1.4.240.127.1.1 = OID: iso.3.6.1.2.1.4.32.1.5.7.1.4.240.127.1.0.24
iso.3.6.1.2.1.4.34.1.5.1.4.240.127.1.255 = OID: iso.3.6.1.2.1.4.32.1.5.7.1.4.240.127.1.0.24

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[nmoray]

@madhupalu will plz help in assigning the right reviewer?