#!/bin/sh
#
# Copyright (c) 1990, 1996, by John Robert LoVerso.
# All rights reserved.
#
# Redistribution and use in source and binary forms are permitted
# provided that the above copyright notice and this paragraph are
# duplicated in all such forms and that any documentation,
# advertising materials, and other materials related to such
# distribution and use acknowledge that the software was developed
# by John Robert LoVerso.
# THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
#
# @(#) $Id$ (jlv
)

#
# This script will read either ASN.1-style MIB files or the ".defs" files
# created by the ISODE "mosy" program on such files.
#
# The output of this script is the "mib.h" file used by tcpdumps' ASN.1/SNMP
# decoding code.
#
# This script needs to be run by "gawk" (GNU awk).  "nawk" will work, but
# dump will get a recursion error if you process LARGE mibs.  While it would
# by farily easy to rewrite this not to use recursion (and also easy to
# eliminate use of gsub and functions to use classic "awk"), you have to 
# order the structure declarations in defined-first order for the compiler
# not to barf; too bad tsort doesn't take arguments.
#

cat << EOF
/*
 * This file was generated by tcpdump/makemib on `date`
 * You probably don't want to edit this by hand!
 *
 * struct mib somename = { desc, oid-octet, type, child-pointer, next-pointer 
};
 */

EOF

# use sed to make the ASN.1 easier to parse
# I should really just use a recursive descent parser in awk, but...
sed \
	-e 's/--\*.*\*--//' \
	-e 's/--.*//' \
	-e 's/\([{}]\)/ \1 /g' \
	$@ \
| gawk '
BEGIN {
	# for sanity, we prep the namespace with objects from RFC-1155
	# (we manually establish the root)
	oid["iso"]=1
	oidadd("org", "iso", 3)
	oidadd("dod", "org", 6)
	oidadd("internet", "dod", 1)
	oidadd("directory", "internet", 1)
	oidadd("mgmt", "internet", 2)
	oidadd("mib", "mgmt", 1)
	oidadd("experimental", "internet", 3)
	oidadd("private", "internet", 4)
	oidadd("enterprises", "private", 1)

	holddesc="none"
}

#
# Read mosy "*.defs" file.  mosy does all the parsing work; we just read
# its simple and straightforward output.  It would not be too hard to make
# tcpdump directly read mosy output, but...
#

NF > 1 && index($2,".")>0 {
	# currently ignore items of the form "{ iso.3.6.1 }"
	if (split($2, p, ".") == 2)
		oidadd($1, p[1], p[2])
	next
}

#
# this next section is simple and naive, but does the job 100%
#

$2$3$4 == "OBJECTIDENTIFIER::=" {
	holddesc="none"
	if (NF == 8)
		oidadd($1, $6, $7)
}
$2 == "OBJECT-TYPE" {
	holddesc=$1
}
$1 == "::=" && holddesc != "none" && NF == 5 {
	oidadd(holddesc, $3, $4)
	holddesc="none"
}

# 
# End of the road - output the data.
#

END {
	print "struct obj"
	dump("iso")
	print "*mibroot = &_iso_obj;"
}

#
# add a new object to the tree
#
#		new OBJECT IDENTIFIER ::= { parent value }
#

function oidadd(new, parent, value) {
	# use safe C identifiers
	gsub(/[-&\/]/,"",new)
	gsub(/[-&\/]/,"",parent)
	# check if parent missing
	if (oid[parent] == 0) {
		printf "/* parse problem: no parent for %s.%s(%d) */\n", \
			parent, new, value
		return
	}
	# check if parent.value already exists
	if (oid[new] > 0 && oid[new] != value) {
		printf "/* parse problem: dup %s.%s(%d) != old (%d) */\n", \
			parent, new, value, oid[new]
		return
	}
	# check for new name for parent.value
	if (child[parent] != "") {
		for (sib = child[parent]; sib != ""; sib = sibling[sib])
			if (oid[sib] == value) {
				printf "/* parse problem: new name \"%s\"" \
					" for %s.%s(%d) ignored */\n", \
						new, parent, sib, value
				return
			}
	}

	oid[new]=value
	if (child[parent] == "") {
		child[parent] = new
	} else {
		sibling[new] = child[parent]
		child[parent] = new
	}
}

#
# old(?) routine to recurse down the tree (in postfix order for convenience)
#

function dump(item, c, s) {
#	newitem=sofar"."item"("oid[item]")"
#	printf "/* %s c=%s s=%s */\n", newitem, child[item], sibling[item]
	c="NULL"
	if (child[item] != "") {
		dump(child[item])
		c = "&_"child[item]"_obj"
	}
	s="NULL"
	if (sibling[item] != "") {
		dump(sibling[item])
		s = "&_"sibling[item]"_obj"
	}
	printf "_%s_obj = {\n\t\"%s\", %d, 0,\n\t%s, %s\n},\n", \
		item, item, oid[item], c, s
}
'
exit 0