An update to a quick note on embedding languages within languages

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An update to a quick note on embedding languages within languages

In making this comment [1] I came across this old post of mine from 2007 [2]
where I lament the amount of code required to query SNMP (Simple Network
Management Protocol) values in C. I took one look at the code I wanted:

> OID sys = SNMPv2-MIB::sysObjectID.0;
>
> if (sys == SNMPv2-SMI::enterprises.5567.1.1) /* riverstone */
> {
> IpAddress destination[] = IP-MIB::ip.24.4.1.1;
> IpAddress mask[] = IP-MIB::ip.24.4.1.2;
> IpAddress nexthop[] = IP-MIB::ip.24.4.1.4;
> int protocol[] = IP-MIB::ip.24.4.1.7;
> int age[] = IP-MIB::ip.24.4.1.8;
> int metric[] = IP-MIB::ip.24.4.1.11;
> int type[] = IP-MIB::ip.24.4.1.6;
> }
> else if (sys == SNMPv2-SMI::enterprises.9.1) /* cisco */
> {
> IpAddress destination[] = RFC1213-MIB::ipRouteDest;
> IpAddress mask[] = RFC1213-MIB::ipRouteMask;
> IpAddress nexthop[] = RFC1213-MIB::ipRouteNextHop;
> int protocol[] = RFC1213-MIB::ipRouteProto;
> int age[] = RFC1213-MIB::ipRouteAge;
> int metric[] = RFC1213-MIB::ipRouteMetric1;
> int type[] = RFC1213-MIB::ipRouteType;
> }
>
> for (i = 0 ; i < destination.length; i++)
> {
> print(
> destination[i],
> mask[i],
> nexthop[i],
> snmp.protocol(protocol[i]),
> metric[i],
> age[i]
> );
> }
>

and remembered—I did that!

Yup. Back in September of 2009 when I first started playing around with Lua
[3]. I installed the SNMP bindings for Lua [4] and wrote the following:

> #!/usr/local/bin/lua
>
> -- http://luasnmp.luaforge.net/snmp.html
>
> snmp = require "snmp"
> OID = snmp.mib.oid
>
> routeprotos =
> {
> "other ", "local ", "netmgmt ", "redirect ",
> "egp ", "ggp ", "hello ", "rip ",
> "is-is ", "es-is ", "igrp ", "bbnspf ",
> "ospf ", "bgp "
> }
>
> print(" Dest Mask NextHop Proto Metric Age")
> print("-------------------------------------------------------------------------------")
>
> router = assert(snmp.open{
> peer = arg[1] or "XXXXXXXXXXXXXXXXXXXXXXXXX" ,
> community = arg[2] or "XXXXXXXXX"
> })
>
> cisco = OID "SNMPv2-SMI::enterprises.9.1"
> riverstone = OID "SNMPv2-SMI::enterprises.5567.1.1"
> sysid = router["SNMPv2-MIB::sysObjectID.0"]
>
> if string.find(sysid,cisco,1,true) then
> shouldbe = OID "RFC1213-MIB::ipRouteDest"
> result =
> {
> { oid = "RFC1213-MIB::ipRouteDest" } ,
> { oid = "RFC1213-MIB::ipRouteMask" } ,
> { oid = "RFC1213-MIB::ipRouteNextHop" } ,
> { oid = "RFC1213-MIB::ipRouteProto" } ,
> { oid = "RFC1213-MIB::ipRouteMetric1" } ,
> { oid = "RFC1213-MIB::ipRouteAge" } ,
> }
> elseif string.find(sysid,riverstone,1,true) then
> shouldbe = OID "IP-MIB::ip.24.4.1.1"
> result =
> {
> { oid = "IP-MIB::ip.24.4.1.1" } ,
> { oid = "IP-MIB::ip.24.4.1.2" } ,
> { oid = "IP-MIB::ip.24.4.1.4" } ,
> { oid = "IP-MIB::ip.24.4.1.7" } ,
> { oid = "IP-MIB::ip.24.4.1.11" } ,
> { oid = "IP-MIB::ip.24.4.1.8" } ,
> }
> end
>
> repeat
> result,err = snmp.getnext(router,result);
>
> if result ~= nil then
> if string.find(result[1].oid,shouldbe,1,true) == nil then break end
>
> print(string.format("%-16s",result[1].value)
> .. string.format("%-16s",result[2].value)
> .. string.format("%-16s",result[3].value)
> .. routeprotos[result[4].value]
> .. string.format("%-6d",result[5].value)
> .. string.format("%-6d",result[6].value)
> )
> end
> until false
> os.exit(0)
>

[1] http://www.flutterby.com/archives/comments/13301.html#artid_46233
[2] gopher://gopher.conman.org/0Phlog:2007/01/19.2
[3] http://www.lua.org/
[4] http://luasnmp.luaforge.net/snmp.html

Email author at [email protected]