52 lines
1.5 KiB
Perl
52 lines
1.5 KiB
Perl
# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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#
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# SPDX-License-Identifier: MPL-2.0
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#
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# This Source Code Form is subject to the terms of the Mozilla Public
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# License, v. 2.0. If a copy of the MPL was not distributed with this
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# file, you can obtain one at https://mozilla.org/MPL/2.0/.
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#
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# See the COPYRIGHT file distributed with this work for additional
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# information regarding copyright ownership.
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#
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# An adhoc server that returns a TC=1 response with the final byte
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# removed to generate UNEXPECTEDEND form dns_message_parse.
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#
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use IO::File;
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use IO::Socket;
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my $localport = int($ENV{'PORT'});
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if (!$localport) { $localport = 5300; }
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printf "localport %u\n", $localport;
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my $sock = IO::Socket::INET->new(LocalAddr => "10.53.0.2",
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LocalPort => $localport, Proto => "udp") or die "$!";
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my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";
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print $pidf "$$\n" or die "cannot write pid file: $!";
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$pidf->close or die "cannot close pid file: $!";
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sub rmpid { unlink "ans.pid"; exit 1; };
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$SIG{INT} = \&rmpid;
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$SIG{TERM} = \&rmpid;
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sub arraystring {
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my $string = join("", @_);
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return $string;
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}
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for (;;) {
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$from = $sock->recv($buf, 512);
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($port, $ip_address) = unpack_sockaddr_in($from);
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$l = length($buf);
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printf "received %u bytes from %s#%u\n", $l, inet_ntoa($ip_address), $port;
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@up = unpack("C[$l]", $buf);
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$up[2] |= 0x80; # QR
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$up[2] |= 0x02; # TC
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$up[3] |= 0x80; # RA
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$l -= 1; # truncate the response 1 byte
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$replydata = pack("C[$l]", @up);
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printf "sent %u bytes\n", $sock->send($replydata);
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}
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