1#! /usr/bin/perl -w
2
3# Copyright (C) 2007-2022 Internet Systems Consortium, Inc. ("ISC")
4#
5# Permission to use, copy, modify, and distribute this software for any
6# purpose with or without fee is hereby granted, provided that the above
7# copyright notice and this permission notice appear in all copies.
8#
9# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11# MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
12# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16#
17#   Internet Systems Consortium, Inc.
18#   PO Box 360
19#   Newmarket, NH 03857 USA
20#   <info@isc.org>
21#   https://www.isc.org/
22
23use strict;
24use English;
25use Time::HiRes qw( sleep );
26use Socket;
27use Socket6;
28use IO::Select;
29
30use dhcp_client;
31
32# XXX: for debugging
33use Data::Dumper;
34
35# not-yet-standard options
36my $OPT_TIME_SERVERS = 40;
37my $OPT_TIME_OFFSET = 41;
38
39# DOCSIS sub-options
40my $DOCSIS_OPT_ORO = 1;
41# 2 to 31 are reserved
42my $DOCSIS_OPT_TFTP_SERVERS = 32;
43my $DOCSIS_OPT_CONFIG_FILE_NAME = 33;
44my $DOCSIS_OPT_SYSLOG_SERVERS = 34;
45my $DOCSIS_OPT_TLV5 = 35;
46my $DOCSIS_OPT_DEVICE_ID = 36;
47my $DOCSIS_OPT_CCC = 37;
48my $DOCSIS_OPT_VERS = 38;
49
50# well-known addresses
51my $All_DHCP_Relay_Agents_and_Servers = "ff02::1:2";
52my $All_DHCP_Servers = "ff05::1:3";
53
54# ports
55my $client_port = 546;
56my $server_port = 547;
57
58# create a new Solicit message
59my $msg = dhcp_client::msg->new($MSG_DECLINE);
60
61# add the Client Identifier (required by DOCSIS and RFC 3315)
62$msg->add_option($OPT_CLIENTID, dhcp_client::duid());
63
64# add the Server identifier (required by RFC 3315)
65$msg->add_option($OPT_SERVERID, "InfiniteEntropy");
66
67# add Elapsed Time, set to 0 on first packet (required by RFC 3315)
68$msg->add_option($OPT_ELAPSED_TIME, "\x00\x00");
69
70# add IA_NA for each interface (required by DOCSIS and RFC 3315)
71# XXX: should this be a single interface only?
72my $iaid = 0;
73foreach my $iface (dhcp_client::iface()) {
74	my $option_data = pack("NNN", ++$iaid, 0, 0);
75	$msg->add_option($OPT_IA_NA, $option_data);
76}
77
78# timeout parameters, from DOCSIS
79my $IRT = $SOL_TIMEOUT;
80my $MRT = $SOL_MAX_RT;
81my $MRC = 4;	# DOCSIS says 4, RFC 3315 says it SHOULD be 0
82my $MRD = 0;
83
84# sleep a random amount of time between 0 and 1 second, required by RFC 3315
85# XXX: this seems pretty stupid
86sleep(rand($SOL_MAX_DELAY));
87
88my $RT;
89my $count = 0;
90my $mrd_end_time;
91if ($MRD != 0) {
92	$mrd_end_time = time() + $MRD;
93}
94my $reply_msg;
95do {
96	# create our socket, and send our Solicit
97	socket(SOCK, PF_INET6, SOCK_DGRAM, getprotobyname('udp')) || die;
98	my $addr = inet_pton(AF_INET6, $All_DHCP_Servers);
99	my $packet = $msg->packet();
100	my $send_ret = send(SOCK, $packet, 0,
101			    pack_sockaddr_in6($server_port, $addr));
102	if (not defined($send_ret)) {
103		printf STDERR
104			"Error \%d sending DHCPv6 Solicit message;\n\%s\n",
105			0+$ERRNO, $ERRNO;
106		exit(1);
107	} elsif ($send_ret != length($packet)) {
108		print STDERR "Unable to send entire DHCPv6 Solicit message.\n";
109		exit(1);
110	}
111	$count++;
112
113	my $RAND = rand(0.2) - 0.1;
114	if (defined $RT) {
115		$RT = 2*$RT + $RAND*$RT;
116		if (($RT > $MRT) && ($MRT != 0)) {
117			$RT = $MRT + $RAND*$RT;
118		}
119	} else {
120		$RT = $IRT + $RAND*$IRT;
121	}
122
123	my $rt_end_time = time() + $RT;
124	if (defined($mrd_end_time) && ($mrd_end_time > $rt_end_time)) {
125		$rt_end_time = $mrd_end_time;
126	}
127
128	for (;;) {
129		my $timeout = $rt_end_time - time();
130		if ($timeout < 0) {
131#			print STDERR "Timeout waiting for DHCPv6 Advertise ",
132#				"or Reply message.\n";
133			last;
134		}
135
136		my @ready = IO::Select->new(\*SOCK)->can_read($timeout);
137
138		if (@ready) {
139			my $reply;
140			my $recv_ret;
141
142			$recv_ret = recv(SOCK, $reply, 1500, 0);
143			if (not defined $recv_ret) {
144				printf STDERR
145					"Error \%d receiving DHCPv6 " .
146						"message;\n\%s\n",
147					0+$ERRNO, $ERRNO;
148				exit(1);
149			}
150
151			$reply_msg = dhcp_client::msg::decode($reply, 1);
152			if (($reply_msg->{msg_type} == $MSG_ADVERTISE) ||
153			    ($reply_msg->{msg_type} == $MSG_REPLY)) {
154			    	last;
155			}
156		}
157	}
158
159} until ($reply_msg ||
160	 (($MRC != 0) && ($count > $MRC)) ||
161	 (defined($mrd_end_time) && ($mrd_end_time > time())));
162
163unless ($reply_msg) {
164	if (($MRC != 0) && ($count >= $MRC)) {
165		print STDERR
166			"No reply after maximum retransmission count.\n";
167	} else {
168		print STDERR
169			"No reply after maximum retransmission duration.\n";
170	}
171}
172
173if ($reply_msg && ($reply_msg->{msg_type} == $MSG_REPLY)) {
174	print "Got DHCPv6 Reply message.\n";
175	exit(0);
176}
177
178#$Data::Dumper::Useqq = 1;
179#print Dumper($msg), "\n";
180#print Dumper($msg->packet()), "\n";
181#
182#print "packet length: ", length($msg->packet()), "\n";
183