#!/bin/sh
# $Id$
#
# Lists the host names associated with each globally routed IPv{4,6} host
# address configured on the caller's box, dispatching RDNS queries to
# validate the authority of each resolved host name, optionally amending
# the AS number and corresponding /descr/ from RADB.
#
#      Author:	vxp/arab <l.illanes@gmx.de>, <irc://arabs.ps/arab>
# Last update:	Sun Aug 22 11:38:01 CEST 2010
#   Tested on:	FreeBSD 7.1, OpenBSD 4.5, and NetBSD 5.0.1.
#    Requires:	SuS sh (1), getopt (1); SuS awk (1) or [gn]awk (1);
#		ISC BIND dig (1); BSD ifconfig (8), and whois (1).
#

# {{{ Tunables
# Maximum string length in characters of an IPv6 address in presentation
# format, as per <netinet6/in6.h>.  Note that an IPv4 address string
# constitutes a subset of the former in terms of length.
ADDRSTRLEN=39

# Maximum number of DNS UDP query attempts, including the initial query,
# and the maximum duration of each query in seconds.  
DIG_TRIES=2
DIG_TIME=2

# XXX
VHOSTS_LIST="/var/run/vhosts"
# }}}
# {{{ subr
_printf() {
	local nflag="\\n"; [ "x-n" = "x${1}" ] && { nflag=""; shift; };
	local line="`printf \"$@\"`"; printf -- "%s${nflag}" "${line}";
	[ -n "${wflag}" ] && { printf -- "%s${nflag}" "${line}"		\
		>> "${VHOSTS_LIST}"; };
};

dig() {
	[ -n "${1}" ] || return;
	local xflag="${1%%[!!]*}" name="${1#!}" class="${2}" IFS="
";	set -- `command dig ${xflag:+-x} "${name}" IN "${class}"	\
		+short +nocomments					\
		+time="${DIG_TIME}" +tries="${DIG_TRIES}"		\
			2>/dev/null`; echo "${1}";
};
# }}}

# trap(1) the relevant set of signals to ensure clean script termination.
abort_exec() { printf "\n--- ABORTED ---\n"; exit 1; };
trap abort_exec HUP INT QUIT PIPE TERM USR1 USR2;

#
# Parse optionally supplied command options to determine the desired mode of
# operation, either cat(1)ting an already present and readable /vhosts/ list
# to the standard output or dispatching individual DNS queries.
for c in `getopt fwah $* 2>/dev/null`
do	case "${c}" in
	-f) fflag=1; ;; -w) wflag=1; ;; -a) aflag=1; ;; -h) hflag=1; ;;
	--) break; ;;
	esac
done;	[ "${hflag}" ] && { echo "usage: $0 [-fwa]"; exit 1; };

[ -r "${VHOSTS_LIST}" -a -z "${fflag}" ]				\
&& { cat "${VHOSTS_LIST}"; }						\
|| {
	[ -n "${wflag}" ] && { printf "" >| "${VHOSTS_LIST}" || exit 2; };

	#
	# Iterate over the subset of IPv{4,6} netif host addresses from every
	# netif that is /up/, resolving each and establishing 2-way RDNS
	# {authority,hostname} confirmation where applicable.
	for ha in `							\
		ifconfig -a						|\
		awk '	 /\tinet6? alias / { print $3; next; }		\
			 /\tinet6? / { print $2; }'			|\
		awk '	!/^((127|10|172|192\.168)\.|(fe..)?:)/		\
			{ print; }' 2>/dev/null`;
	do	type="NO HOST" pf="4" q="A" radb="" host="";

		# Infer the protocol family from the presentation format.
		[ "x${ha##*:*}" = "x${ha}" ] || { pf="6"; q="AAAA"; };

		[ -n "${aflag}" ] && {
		# {{{ RADB
		radb="`							\
		whois -h whois.radb.net "${ha}" 2>/dev/null | awk '	\
		/^[^:]+:/ {						\
			gsub(/(\t| )+/, " ", $0); split($0, a, ": ");	\
			if(v[a[1]]) { next; } else { v[a[1]] = a[2]; };	\
		}							\
									\
		END { printf("[%8.8s/%16.16s]", v["origin"], v["mnt-by"]); }'`";
		# }}}
		};

		_printf -n "%-${ADDRSTRLEN}s${radb} %-2s " "${ha}" "[IPv${pf}]";
		host="`dig !${ha} PTR`"; [ -n "${host}" ] && {
			[ "x`dig ${host} ${q}`" = "x${ha}" ]		\
			&& type="PTR" || type="NO RDNS"; };

		_printf "%-12s %s" "--${type}-->" "${host}"
	done
};

# vim:ts=8 sw=8 tw=80 noexpandtab foldmethod=marker