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Diffstat (limited to 'bin/tests/system/upforwd/ans4/ans.pl')
| -rw-r--r-- | bin/tests/system/upforwd/ans4/ans.pl | 361 |
1 files changed, 361 insertions, 0 deletions
diff --git a/bin/tests/system/upforwd/ans4/ans.pl b/bin/tests/system/upforwd/ans4/ans.pl new file mode 100644 index 0000000..e98c2cf --- /dev/null +++ b/bin/tests/system/upforwd/ans4/ans.pl @@ -0,0 +1,361 @@ +#!/usr/bin/perl +# +# Copyright (C) Internet Systems Consortium, Inc. ("ISC") +# +# This Source Code Form is subject to the terms of the Mozilla Public +# License, v. 2.0. If a copy of the MPL was not distributed with this +# file, You can obtain one at http://mozilla.org/MPL/2.0/. +# +# See the COPYRIGHT file distributed with this work for additional +# information regarding copyright ownership. + +# +# This is the name server from hell. It provides canned +# responses based on pattern matching the queries, and +# can be reprogrammed on-the-fly over a TCP connection. +# +# The server listens for control connections on port 5301. +# A control connection is a TCP stream of lines like +# +# /pattern/ +# name ttl type rdata +# name ttl type rdata +# ... +# /pattern/ +# name ttl type rdata +# name ttl type rdata +# ... +# +# There can be any number of patterns, each associated +# with any number of response RRs. Each pattern is a +# Perl regular expression. +# +# Each incoming query is converted into a string of the form +# "qname qtype" (the printable query domain name, space, +# printable query type) and matched against each pattern. +# +# The first pattern matching the query is selected, and +# the RR following the pattern line are sent in the +# answer section of the response. +# +# Each new control connection causes the current set of +# patterns and responses to be cleared before adding new +# ones. +# +# The server handles UDP and TCP queries. Zone transfer +# responses work, but must fit in a single 64 k message. +# +# Now you can add TSIG, just specify key/key data with: +# +# /pattern <key> <key_data>/ +# name ttl type rdata +# name ttl type rdata +# +# Note that this data will still be sent with any request for +# pattern, only this data will be signed. Currently, this is only +# done for TCP. + + +use IO::File; +use IO::Socket; +use Data::Dumper; +use Net::DNS; +use Net::DNS::Packet; +use strict; + +# Ignore SIGPIPE so we won't fail if peer closes a TCP socket early +local $SIG{PIPE} = 'IGNORE'; + +# Flush logged output after every line +local $| = 1; + +my $server_addr = "10.53.0.4"; + +my $localport = int($ENV{'PORT'}); +if (!$localport) { $localport = 5300; } + +my $udpsock = IO::Socket::INET->new(LocalAddr => "$server_addr", + LocalPort => $localport, Proto => "udp", Reuse => 1) or die "$!"; + +my $tcpsock = IO::Socket::INET->new(LocalAddr => "$server_addr", + LocalPort => $localport, Proto => "tcp", Listen => 5, Reuse => 1) or die "$!"; + +print "listening on $server_addr:$localport.\n"; + +my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!"; +print $pidf "$$\n" or die "cannot write pid file: $!"; +$pidf->close or die "cannot close pid file: $!";; +sub rmpid { unlink "ans.pid"; exit 1; }; + +$SIG{INT} = \&rmpid; +$SIG{TERM} = \&rmpid; + +#my @answers = (); +my @rules; +sub handleUDP { + my ($buf) = @_; + my $packet; + + if ($Net::DNS::VERSION > 0.68) { + $packet = new Net::DNS::Packet(\$buf, 0); + $@ and die $@; + } else { + my $err; + ($packet, $err) = new Net::DNS::Packet(\$buf, 0); + $err and die $err; + } + + $packet->header->qr(1); + $packet->header->aa(1); + + my @questions = $packet->question; + my $qname = $questions[0]->qname; + my $qtype = $questions[0]->qtype; + + # get the existing signature if any, and clear the additional section + my $prev_tsig; + while (my $rr = $packet->pop("additional")) { + if ($rr->type eq "TSIG") { + $prev_tsig = $rr; + } + } + + my $r; + foreach $r (@rules) { + my $pattern = $r->{pattern}; + my($dbtype, $key_name, $key_data) = split(/ /,$pattern); + print "[handleUDP] $dbtype, $key_name, $key_data \n"; + if ("$qname $qtype" =~ /$dbtype/) { + my $a; + foreach $a (@{$r->{answer}}) { + $packet->push("answer", $a); + } + if(defined($key_name) && defined($key_data)) { + # Sign the packet + print " Signing the response with " . + "$key_name/$key_data\n"; + my $tsig = Net::DNS::RR-> + new("$key_name TSIG $key_data"); + + # These kluges are necessary because Net::DNS + # doesn't know how to sign responses. We + # clear compnames so that the TSIG key and + # algorithm name won't be compressed, and + # add one to arcount because the signing + # function will attempt to decrement it, + # which is incorrect in a response. Finally + # we set request_mac to the previous digest. + $packet->{"compnames"} = {}; + $packet->{"header"}{"arcount"} += 1; + if (defined($prev_tsig)) { + my $rmac = pack('n H*', + $prev_tsig->mac_size, + $prev_tsig->mac); + $tsig->{"request_mac"} = + unpack("H*", $rmac); + } + + $packet->sign_tsig($tsig); + } + last; + } + } + #$packet->print; + + return $packet->data; +} + +# namelen: +# given a stream of data, reads a DNS-formatted name and returns its +# total length, thus making it possible to skip past it. +sub namelen { + my ($data) = @_; + my $len = 0; + my $label_len = 0; + do { + $label_len = unpack("c", $data); + $data = substr($data, $label_len + 1); + $len += $label_len + 1; + } while ($label_len != 0); + return ($len); +} + +# packetlen: +# given a stream of data, reads a DNS wire-format packet and returns +# its total length, making it possible to skip past it. +sub packetlen { + my ($data) = @_; + my $q; + my $rr; + + my ($header, $offset) = Net::DNS::Header->parse(\$data); + for (1 .. $header->qdcount) { + ($q, $offset) = Net::DNS::Question->parse(\$data, $offset); + } + for (1 .. $header->ancount) { + ($rr, $offset) = Net::DNS::RR->parse(\$data, $offset); + } + for (1 .. $header->nscount) { + ($rr, $offset) = Net::DNS::RR->parse(\$data, $offset); + } + for (1 .. $header->arcount) { + ($rr, $offset) = Net::DNS::RR->parse(\$data, $offset); + } + return $offset; +} + +# sign_tcp_continuation: +# This is a hack to correct the problem that Net::DNS has no idea how +# to sign multiple-message TCP responses. Several data that are included +# in the digest when signing a query or the first message of a response are +# omitted when signing subsequent messages in a TCP stream. +# +# Net::DNS::Packet->sign_tsig() has the ability to use a custom signing +# function (specified by calling Packet->sign_func()). We use this +# function as the signing function for TCP continuations, and it removes +# the unwanted data from the digest before calling the default sign_hmac +# function. +sub sign_tcp_continuation { + my ($key, $data) = @_; + + # copy out first two bytes: size of the previous MAC + my $rmacsize = unpack("n", $data); + $data = substr($data, 2); + + # copy out previous MAC + my $rmac = substr($data, 0, $rmacsize); + $data = substr($data, $rmacsize); + + # try parsing out the packet information + my $plen = packetlen($data); + my $pdata = substr($data, 0, $plen); + $data = substr($data, $plen); + + # remove the keyname, ttl, class, and algorithm name + $data = substr($data, namelen($data)); + $data = substr($data, 6); + $data = substr($data, namelen($data)); + + # preserve the TSIG data + my $tdata = substr($data, 0, 8); + + # prepare a new digest and sign with it + $data = pack("n", $rmacsize) . $rmac . $pdata . $tdata; + return Net::DNS::RR::TSIG::sign_hmac($key, $data); +} + +sub handleTCP { + my ($buf) = @_; + my $packet; + + if ($Net::DNS::VERSION > 0.68) { + $packet = new Net::DNS::Packet(\$buf, 0); + $@ and die $@; + } else { + my $err; + ($packet, $err) = new Net::DNS::Packet(\$buf, 0); + $err and die $err; + } + + $packet->header->qr(1); + $packet->header->aa(1); + + my @questions = $packet->question; + my $qname = $questions[0]->qname; + my $qtype = $questions[0]->qtype; + + # get the existing signature if any, and clear the additional section + my $prev_tsig; + my $signer; + while (my $rr = $packet->pop("additional")) { + if ($rr->type eq "TSIG") { + $prev_tsig = $rr; + } + } + + my @results = (); + my $count_these = 0; + + my $r; + foreach $r (@rules) { + my $pattern = $r->{pattern}; + my($dbtype, $key_name, $key_data) = split(/ /,$pattern); + print "[handleTCP] $dbtype, $key_name, $key_data \n"; + if ("$qname $qtype" =~ /$dbtype/) { + $count_these++; + my $a; + foreach $a (@{$r->{answer}}) { + $packet->push("answer", $a); + } + if(defined($key_name) && defined($key_data)) { + # sign the packet + print " Signing the data with " . + "$key_name/$key_data\n"; + + my $tsig = Net::DNS::RR-> + new("$key_name TSIG $key_data"); + + # These kluges are necessary because Net::DNS + # doesn't know how to sign responses. We + # clear compnames so that the TSIG key and + # algorithm name won't be compressed, and + # add one to arcount because the signing + # function will attempt to decrement it, + # which is incorrect in a response. Finally + # we set request_mac to the previous digest. + $packet->{"compnames"} = {}; + $packet->{"header"}{"arcount"} += 1; + if (defined($prev_tsig)) { + my $rmac = pack('n H*', + $prev_tsig->mac_size, + $prev_tsig->mac); + $tsig->{"request_mac"} = + unpack("H*", $rmac); + } + + $tsig->sign_func($signer) if defined($signer); + $packet->sign_tsig($tsig); + $signer = \&sign_tcp_continuation; + + my $copy = + Net::DNS::Packet->new(\($packet->data)); + $prev_tsig = $copy->pop("additional"); + } + #$packet->print; + push(@results,$packet->data); + $packet = new Net::DNS::Packet(\$buf, 0); + $packet->header->qr(1); + $packet->header->aa(1); + } + } + print " A total of $count_these patterns matched\n"; + return \@results; +} + +# Main +my $rin; +my $rout; +for (;;) { + $rin = ''; + vec($rin, fileno($tcpsock), 1) = 1; + vec($rin, fileno($udpsock), 1) = 1; + + select($rout = $rin, undef, undef, undef); + + if (vec($rout, fileno($udpsock), 1)) { + printf "UDP request\n"; + my $buf; + $udpsock->recv($buf, 512); + } elsif (vec($rout, fileno($tcpsock), 1)) { + my $conn = $tcpsock->accept; + my $buf; + for (;;) { + my $lenbuf; + my $n = $conn->sysread($lenbuf, 2); + last unless $n == 2; + my $len = unpack("n", $lenbuf); + $n = $conn->sysread($buf, $len); + } + sleep(1); + } +} |