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From: emv@math.lsa.umich.edu (Edward Vielmetti)
Newsgroups: comp.lang.perl
Subject: gnu awk extended to speak SNMP
Message-ID: <EMV.90Mar6152351@duby.math.lsa.umich.edu>
Date: 6 Mar 90 20:23:51 GMT
Sender: news@math.lsa.umich.edu
Organization: University of Michigan Math Dept., Ann Arbor MI.
Lines: 107


In article <16053.636724600@cheetah.nyser.net> in
comp.protocols.iso.dev-environ, Marshall Rose
<mrose@CHEETAH.NYSER.NET> describes modifications to GNU Awk that
speak to the ISODE 6.0 SNMP agent.  I enclose a snippet and refer you
to the actual article for more info.

You'll have to ask Marshall about availability of these modifications
-- I wouldn't be altogether opposed to seeing them put into my
favorite rapid prototyping language for Unix....

From the article:

    >> GNU Awk

    A month back, I saw an announcement of the CMU SNMP package, which had a
    really neat idea.  They took the popular netstat program and modified it
    to use SNMP iteractions to read information rather than just groking the
    kernel.  I liked this idea so much that I decided to steal it!

    But, the CMU people did a lot more work than I thought they needed: they
    actually modified the netstat source.  Instead, I thought, what one
    needed was a rapid-prototyping language for SNMP.  Well, the
    rapid-prototyping language for UNIX is called awk, and the version of
    awk which is easiest for the most people to get the source to is GNU
    Awk.  So, I modified my copy of GNU Awk (2.11 beta) to know about SNMP.
    The idea is that I now write awk scripts that read, process, and display
    SNMP variables from whatever agents I am interested in.  For example,
    here is how I produce the output of "netstat -i":
    ///////
    BEGIN {
	    printf "%-4s %-5s %-14s %-14s %-7s %-5s %-7s %-5s %-4s %-5s\n",
		    "Name",
			 "Mtu",
			      "Net/Dest",
				    "Address",
					  "Ipkts",
					      "Ierrs",
						   "Opkts",
							 "Oerrs",
							      "Drop",
								   "Queue";

	    didone = 0;
	    for (i in ifIndex) {
		didone = 1;

		dest = "";
		addr = "";
		for (j in ipAdEntAddr) {
		    if (ipAdEntIfIndex == ifIndex) {
			split(addr = ipAdEntAddr, a, ".");
			split(ipAdEntNetMask, b, ".");
			dest = bit_and(a[1],b[1]) "." \
			       bit_and(a[2],b[2]) "." \
			       bit_and(a[3],b[3]) "." \
			       bit_and(a[4],b[4]);
			break;
		    }
		}

		printf (length(ifDescr) <= 4 ? "%-4s " : "%s\n     "),
		    ifDescr;
		printf      "%-5d %-14s %-14s %-7d %-5d %-7d %-5d %-4d %-5d\n",
			     ifMtu,
				  dest,
					addr,
					      ifInUcastPkts+ifInNUcastPkts,
						   ifInErrors,
							ifOutUcastPkts+ifOutNUcastPkts,
							     ifOutErrors,
								  ifOutDiscards,
								       ifOutQLen;
		if (oflag)
		    for (j in clnpAdEntAddr) {
			if (clnpAdEntIfIndex == ifIndex) {
			    printf "%-4s %-5s %-14s NS+%s\n",
				   "",  "",  "",   clnpAdEntAddr;
			    break;
			}
		    }
	    }
	    if (!didone && DIAGNOSTIC)
		printf "ifTable: %s\n", DIAGNOSTIC;

	  }
    ///////

    So, I wrote a shell script which parses a command line to netstat, and
    invokes gawk on the write awk script.  I then modified the SNMP agent to
    know about UNIX-specific MIB variables that are useful in making the
    netstat output appear more UNIX-like.  So, when I run gawk and talk to a
    UNIX box, I get all the columns of output I want.  When I talk to some
    other box, I get the subset of the information provided by MIB-I/II.

    The output of the shell script above looks like this:
    ///////
% s-netstat -i
Name Mtu   Net/Dest       Address        Ipkts   Ierrs Opkts   Oerrs Drop Queue
le0  1500  192.52.180.0   192.52.180.1   357417  35    327444  0     0    0    
lo0  1536  127.0.0.0      127.0.0.1      35709   0     35709   0     0    0    
    ///////

(me again)

--Ed
Edward Vielmetti, U of Michigan perl dept.