util/perl/TLSProxy/Proxy.pm - third_party/openssl - Git at Google

 # Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
 #
 # Licensed under the Apache License 2.0 (the "License").  You may not use
 # this file except in compliance with the License.  You can obtain a copy
 # in the file LICENSE in the source distribution or at
 # https://www.openssl.org/source/license.html

 use strict;
 use POSIX ":sys_wait_h";

 package TLSProxy::Proxy;

 use File::Spec;
 use IO::Socket;
 use IO::Select;
 use TLSProxy::Record;
 use TLSProxy::Message;
 use TLSProxy::ClientHello;
 use TLSProxy::ServerHello;
 use TLSProxy::EncryptedExtensions;
 use TLSProxy::Certificate;
 use TLSProxy::CertificateRequest;
 use TLSProxy::CertificateVerify;
 use TLSProxy::ServerKeyExchange;
 use TLSProxy::NewSessionTicket;

 my $have_IPv6;
 my $IP_factory;

 BEGIN
 {
     # IO::Socket::IP is on the core module list, IO::Socket::INET6 isn't.
     # However, IO::Socket::INET6 is older and is said to be more widely
     # deployed for the moment, and may have less bugs, so we try the latter
     # first, then fall back on the core modules.  Worst case scenario, we
     # fall back to IO::Socket::INET, only supports IPv4.
     eval {
         require IO::Socket::INET6;
         my $s = IO::Socket::INET6->new(
             LocalAddr => "::1",
             LocalPort => 0,
             Listen=>1,
             );
         $s or die "\n";
         $s->close();
     };
     if ($@ eq "") {
         $IP_factory = sub { IO::Socket::INET6->new(Domain => AF_INET6, @_); };
         $have_IPv6 = 1;
     } else {
         eval {
             require IO::Socket::IP;
             my $s = IO::Socket::IP->new(
                 LocalAddr => "::1",
                 LocalPort => 0,
                 Listen=>1,
                 );
             $s or die "\n";
             $s->close();
         };
         if ($@ eq "") {
             $IP_factory = sub { IO::Socket::IP->new(@_); };
             $have_IPv6 = 1;
         } else {
             $IP_factory = sub { IO::Socket::INET->new(@_); };
             $have_IPv6 = 0;
         }
     }
 }

 my $is_tls13 = 0;
 my $ciphersuite = undef;

 sub new
 {
     my $class = shift;
     my ($filter,
         $execute,
         $cert,
         $debug) = @_;

     my $self = {
         #Public read/write
         proxy_addr => $have_IPv6 ? "[::1]" : "127.0.0.1",
         filter => $filter,
         serverflags => "",
         clientflags => "",
         serverconnects => 1,
         reneg => 0,
         sessionfile => undef,

         #Public read
         proxy_port => 0,
         server_port => 0,
         serverpid => 0,
         clientpid => 0,
         execute => $execute,
         cert => $cert,
         debug => $debug,
         cipherc => "",
         ciphersuitesc => "",
         ciphers => "AES128-SHA",
         ciphersuitess => "TLS_AES_128_GCM_SHA256",
         flight => -1,
         direction => -1,
         partial => ["", ""],
         record_list => [],
         message_list => [],
     };

     # Create the Proxy socket
     my $proxaddr = $self->{proxy_addr};
     $proxaddr =~ s/[\[\]]//g; # Remove [ and ]
     my @proxyargs = (
         LocalHost   => $proxaddr,
         LocalPort   => 0,
         Proto       => "tcp",
         Listen      => SOMAXCONN,
        );

     if (my $sock = $IP_factory->(@proxyargs)) {
         $self->{proxy_sock} = $sock;
         $self->{proxy_port} = $sock->sockport();
         $self->{proxy_addr} = $sock->sockhost();
         $self->{proxy_addr} =~ s/(.*:.*)/[$1]/;
         print "Proxy started on port ",
               "$self->{proxy_addr}:$self->{proxy_port}\n";
         # use same address for s_server
         $self->{server_addr} = $self->{proxy_addr};
     } else {
         warn "Failed creating proxy socket (".$proxaddr.",0): $!\n";
     }

     return bless $self, $class;
 }

 sub DESTROY
 {
     my $self = shift;

     $self->{proxy_sock}->close() if $self->{proxy_sock};
 }

 sub clearClient
 {
     my $self = shift;

     $self->{cipherc} = "";
     $self->{ciphersuitec} = "";
     $self->{flight} = -1;
     $self->{direction} = -1;
     $self->{partial} = ["", ""];
     $self->{record_list} = [];
     $self->{message_list} = [];
     $self->{clientflags} = "";
     $self->{sessionfile} = undef;
     $self->{clientpid} = 0;
     $is_tls13 = 0;
     $ciphersuite = undef;

     TLSProxy::Message->clear();
     TLSProxy::Record->clear();
 }

 sub clear
 {
     my $self = shift;

     $self->clearClient;
     $self->{ciphers} = "AES128-SHA";
     $self->{ciphersuitess} = "TLS_AES_128_GCM_SHA256";
     $self->{serverflags} = "";
     $self->{serverconnects} = 1;
     $self->{serverpid} = 0;
     $self->{reneg} = 0;
 }

 sub restart
 {
     my $self = shift;

     $self->clear;
     $self->start;
 }

 sub clientrestart
 {
     my $self = shift;

     $self->clear;
     $self->clientstart;
 }

 sub connect_to_server
 {
     my $self = shift;
     my $servaddr = $self->{server_addr};

     $servaddr =~ s/[\[\]]//g; # Remove [ and ]

     my $sock = $IP_factory->(PeerAddr => $servaddr,
                              PeerPort => $self->{server_port},
                              Proto => 'tcp');
     if (!defined($sock)) {
         my $err = $!;
         kill(3, $self->{real_serverpid});
         die "unable to connect: $err\n";
     }

     $self->{server_sock} = $sock;
 }

 sub start
 {
     my ($self) = shift;
     my $pid;

     if ($self->{proxy_sock} == 0) {
         return 0;
     }

     my $execcmd = $self->execute
         ." s_server -max_protocol TLSv1.3 -no_comp -rev -engine ossltest"
         #In TLSv1.3 we issue two session tickets. The default session id
         #callback gets confused because the ossltest engine causes the same
         #session id to be created twice due to the changed random number
         #generation. Using "-ext_cache" replaces the default callback with a
         #different one that doesn't get confused.
         ." -ext_cache"
         ." -accept $self->{server_addr}:0"
         ." -cert ".$self->cert." -cert2 ".$self->cert
         ." -naccept ".$self->serverconnects;
     if ($self->ciphers ne "") {
         $execcmd .= " -cipher ".$self->ciphers;
     }
     if ($self->ciphersuitess ne "") {
         $execcmd .= " -ciphersuites ".$self->ciphersuitess;
     }
     if ($self->serverflags ne "") {
         $execcmd .= " ".$self->serverflags;
     }
     if ($self->debug) {
         print STDERR "Server command: $execcmd\n";
     }

     open(my $savedin, "<&STDIN");

     # Temporarily replace STDIN so that sink process can inherit it...
     $pid = open(STDIN, "$execcmd 2>&1 |") or die "Failed to $execcmd: $!\n";
     $self->{real_serverpid} = $pid;

     # Process the output from s_server until we find the ACCEPT line, which
     # tells us what the accepting address and port are.
     while (<>) {
         print;
         s/\R$//;                # Better chomp
         next unless (/^ACCEPT\s.*:(\d+)$/);
         $self->{server_port} = $1;
         last;
     }

     if ($self->{server_port} == 0) {
         # This actually means that s_server exited, because otherwise
         # we would still searching for ACCEPT...
         waitpid($pid, 0);
         die "no ACCEPT detected in '$execcmd' output: $?\n";
     }

     # Just make sure everything else is simply printed [as separate lines].
     # The sub process simply inherits our STD* and will keep consuming
     # server's output and printing it as long as there is anything there,
     # out of our way.
     my $error;
     $pid = undef;
     if (eval { require Win32::Process; 1; }) {
         if (Win32::Process::Create(my $h, $^X, "perl -ne print", 0, 0, ".")) {
             $pid = $h->GetProcessID();
             $self->{proc_handle} = $h;  # hold handle till next round [or exit]
         } else {
             $error = Win32::FormatMessage(Win32::GetLastError());
         }
     } else {
         if (defined($pid = fork)) {
             $pid or exec("$^X -ne print") or exit($!);
         } else {
             $error = $!;
         }
     }

     # Change back to original stdin
     open(STDIN, "<&", $savedin);
     close($savedin);

     if (!defined($pid)) {
         kill(3, $self->{real_serverpid});
         die "Failed to capture s_server's output: $error\n";
     }

     $self->{serverpid} = $pid;

     print STDERR "Server responds on ",
                  "$self->{server_addr}:$self->{server_port}\n";

     # Connect right away...
     $self->connect_to_server();

     return $self->clientstart;
 }

 sub clientstart
 {
     my ($self) = shift;

     if ($self->execute) {
         my $pid;
         my $execcmd = $self->execute
              ." s_client -max_protocol TLSv1.3 -engine ossltest"
              ." -connect $self->{proxy_addr}:$self->{proxy_port}";
         if ($self->cipherc ne "") {
             $execcmd .= " -cipher ".$self->cipherc;
         }
         if ($self->ciphersuitesc ne "") {
             $execcmd .= " -ciphersuites ".$self->ciphersuitesc;
         }
         if ($self->clientflags ne "") {
             $execcmd .= " ".$self->clientflags;
         }
         if ($self->clientflags !~ m/-(no)?servername/) {
             $execcmd .= " -servername localhost";
         }
         if (defined $self->sessionfile) {
             $execcmd .= " -ign_eof";
         }
         if ($self->debug) {
             print STDERR "Client command: $execcmd\n";
         }

         open(my $savedout, ">&STDOUT");
         # If we open pipe with new descriptor, attempt to close it,
         # explicitly or implicitly, would incur waitpid and effectively
         # dead-lock...
         if (!($pid = open(STDOUT, "| $execcmd"))) {
             my $err = $!;
             kill(3, $self->{real_serverpid});
             die "Failed to $execcmd: $err\n";
         }
         $self->{clientpid} = $pid;

         # queue [magic] input
         print $self->reneg ? "R" : "test";

         # this closes client's stdin without waiting for its pid
         open(STDOUT, ">&", $savedout);
         close($savedout);
     }

     # Wait for incoming connection from client
     my $fdset = IO::Select->new($self->{proxy_sock});
     if (!$fdset->can_read(60)) {
         kill(3, $self->{real_serverpid});
         die "s_client didn't try to connect\n";
     }

     my $client_sock;
     if(!($client_sock = $self->{proxy_sock}->accept())) {
         warn "Failed accepting incoming connection: $!\n";
         return 0;
     }

     print "Connection opened\n";

     my $server_sock = $self->{server_sock};
     my $indata;

     #Wait for either the server socket or the client socket to become readable
     $fdset = IO::Select->new($server_sock, $client_sock);
     my @ready;
     my $ctr = 0;
     local $SIG{PIPE} = "IGNORE";
     $self->{saw_session_ticket} = undef;
     while($fdset->count && $ctr < 10) {
         if (defined($self->{sessionfile})) {
             # s_client got -ign_eof and won't be exiting voluntarily, so we
             # look for data *and* session ticket...
             last if TLSProxy::Message->success()
                     && $self->{saw_session_ticket};
         }
         if (!(@ready = $fdset->can_read(1))) {
             $ctr++;
             next;
         }
         foreach my $hand (@ready) {
             if ($hand == $server_sock) {
                 if ($server_sock->sysread($indata, 16384)) {
                     if ($indata = $self->process_packet(1, $indata)) {
                         $client_sock->syswrite($indata) or goto END;
                     }
                     $ctr = 0;
                 } else {
                     $fdset->remove($server_sock);
                     $client_sock->shutdown(SHUT_WR);
                 }
             } elsif ($hand == $client_sock) {
                 if ($client_sock->sysread($indata, 16384)) {
                     if ($indata = $self->process_packet(0, $indata)) {
                         $server_sock->syswrite($indata) or goto END;
                     }
                     $ctr = 0;
                 } else {
                     $fdset->remove($client_sock);
                     $server_sock->shutdown(SHUT_WR);
                 }
             } else {
                 kill(3, $self->{real_serverpid});
                 die "Unexpected handle";
             }
         }
     }

     if ($ctr >= 10) {
         kill(3, $self->{real_serverpid});
         die "No progress made";
     }

     END:
     print "Connection closed\n";
     if($server_sock) {
         $server_sock->close();
         $self->{server_sock} = undef;
     }
     if($client_sock) {
         #Closing this also kills the child process
         $client_sock->close();
     }

     my $pid;
     if (--$self->{serverconnects} == 0) {
         $pid = $self->{serverpid};
         print "Waiting for 'perl -ne print' process to close: $pid...\n";
         $pid = waitpid($pid, 0);
         if ($pid > 0) {
             die "exit code $? from 'perl -ne print' process\n" if $? != 0;
         } elsif ($pid == 0) {
             kill(3, $self->{real_serverpid});
             die "lost control over $self->{serverpid}?";
         }
         $pid = $self->{real_serverpid};
         print "Waiting for s_server process to close: $pid...\n";
         # it's done already, just collect the exit code [and reap]...
         waitpid($pid, 0);
         die "exit code $? from s_server process\n" if $? != 0;
     } else {
         # It's a bit counter-intuitive spot to make next connection to
         # the s_server. Rationale is that established connection works
         # as synchronization point, in sense that this way we know that
         # s_server is actually done with current session...
         $self->connect_to_server();
     }
     $pid = $self->{clientpid};
     print "Waiting for s_client process to close: $pid...\n";
     waitpid($pid, 0);

     return 1;
 }

 sub process_packet
 {
     my ($self, $server, $packet) = @_;
     my $len_real;
     my $decrypt_len;
     my $data;
     my $recnum;

     if ($server) {
         print "Received server packet\n";
     } else {
         print "Received client packet\n";
     }

     if ($self->{direction} != $server) {
         $self->{flight} = $self->{flight} + 1;
         $self->{direction} = $server;
     }

     print "Packet length = ".length($packet)."\n";
     print "Processing flight ".$self->flight."\n";

     #Return contains the list of record found in the packet followed by the
     #list of messages in those records and any partial message
     my @ret = TLSProxy::Record->get_records($server, $self->flight,
                                             $self->{partial}[$server].$packet);
     $self->{partial}[$server] = $ret[2];
     push @{$self->{record_list}}, @{$ret[0]};
     push @{$self->{message_list}}, @{$ret[1]};

     print "\n";

     if (scalar(@{$ret[0]}) == 0 or length($ret[2]) != 0) {
         return "";
     }

     #Finished parsing. Call user provided filter here
     if (defined $self->filter) {
         $self->filter->($self);
     }

     #Take a note on NewSessionTicket
     foreach my $message (reverse @{$self->{message_list}}) {
         if ($message->{mt} == TLSProxy::Message::MT_NEW_SESSION_TICKET) {
             $self->{saw_session_ticket} = 1;
             last;
         }
     }

     #Reconstruct the packet
     $packet = "";
     foreach my $record (@{$self->record_list}) {
         $packet .= $record->reconstruct_record($server);
     }

     print "Forwarded packet length = ".length($packet)."\n\n";

     return $packet;
 }

 #Read accessors
 sub execute
 {
     my $self = shift;
     return $self->{execute};
 }
 sub cert
 {
     my $self = shift;
     return $self->{cert};
 }
 sub debug
 {
     my $self = shift;
     return $self->{debug};
 }
 sub flight
 {
     my $self = shift;
     return $self->{flight};
 }
 sub record_list
 {
     my $self = shift;
     return $self->{record_list};
 }
 sub success
 {
     my $self = shift;
     return $self->{success};
 }
 sub end
 {
     my $self = shift;
     return $self->{end};
 }
 sub supports_IPv6
 {
     my $self = shift;
     return $have_IPv6;
 }
 sub proxy_addr
 {
     my $self = shift;
     return $self->{proxy_addr};
 }
 sub proxy_port
 {
     my $self = shift;
     return $self->{proxy_port};
 }
 sub server_addr
 {
     my $self = shift;
     return $self->{server_addr};
 }
 sub server_port
 {
     my $self = shift;
     return $self->{server_port};
 }
 sub serverpid
 {
     my $self = shift;
     return $self->{serverpid};
 }
 sub clientpid
 {
     my $self = shift;
     return $self->{clientpid};
 }

 #Read/write accessors
 sub filter
 {
     my $self = shift;
     if (@_) {
         $self->{filter} = shift;
     }
     return $self->{filter};
 }
 sub cipherc
 {
     my $self = shift;
     if (@_) {
         $self->{cipherc} = shift;
     }
     return $self->{cipherc};
 }
 sub ciphersuitesc
 {
     my $self = shift;
     if (@_) {
         $self->{ciphersuitesc} = shift;
     }
     return $self->{ciphersuitesc};
 }
 sub ciphers
 {
     my $self = shift;
     if (@_) {
         $self->{ciphers} = shift;
     }
     return $self->{ciphers};
 }
 sub ciphersuitess
 {
     my $self = shift;
     if (@_) {
         $self->{ciphersuitess} = shift;
     }
     return $self->{ciphersuitess};
 }
 sub serverflags
 {
     my $self = shift;
     if (@_) {
         $self->{serverflags} = shift;
     }
     return $self->{serverflags};
 }
 sub clientflags
 {
     my $self = shift;
     if (@_) {
         $self->{clientflags} = shift;
     }
     return $self->{clientflags};
 }
 sub serverconnects
 {
     my $self = shift;
     if (@_) {
         $self->{serverconnects} = shift;
     }
     return $self->{serverconnects};
 }
 # This is a bit ugly because the caller is responsible for keeping the records
 # in sync with the updated message list; simply updating the message list isn't
 # sufficient to get the proxy to forward the new message.
 # But it does the trick for the one test (test_sslsessiontick) that needs it.
 sub message_list
 {
     my $self = shift;
     if (@_) {
         $self->{message_list} = shift;
     }
     return $self->{message_list};
 }

 sub fill_known_data
 {
     my $length = shift;
     my $ret = "";
     for (my $i = 0; $i < $length; $i++) {
         $ret .= chr($i);
     }
     return $ret;
 }

 sub is_tls13
 {
     my $class = shift;
     if (@_) {
         $is_tls13 = shift;
     }
     return $is_tls13;
 }

 sub reneg
 {
     my $self = shift;
     if (@_) {
         $self->{reneg} = shift;
     }
     return $self->{reneg};
 }

 #Setting a sessionfile means that the client will not close until the given
 #file exists. This is useful in TLSv1.3 where otherwise s_client will close
 #immediately at the end of the handshake, but before the session has been
 #received from the server. A side effect of this is that s_client never sends
 #a close_notify, so instead we consider success to be when it sends application
 #data over the connection.
 sub sessionfile
 {
     my $self = shift;
     if (@_) {
         $self->{sessionfile} = shift;
         TLSProxy::Message->successondata(1);
     }
     return $self->{sessionfile};
 }

 sub ciphersuite
 {
     my $class = shift;
     if (@_) {
         $ciphersuite = shift;
     }
     return $ciphersuite;
 }

 1;
	# Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
	#
	# Licensed under the Apache License 2.0 (the "License"). You may not use
	# this file except in compliance with the License. You can obtain a copy
	# in the file LICENSE in the source distribution or at
	# https://www.openssl.org/source/license.html

	use strict;
	use POSIX ":sys_wait_h";

	package TLSProxy::Proxy;

	use File::Spec;
	use IO::Socket;
	use IO::Select;
	use TLSProxy::Record;
	use TLSProxy::Message;
	use TLSProxy::ClientHello;
	use TLSProxy::ServerHello;
	use TLSProxy::EncryptedExtensions;
	use TLSProxy::Certificate;
	use TLSProxy::CertificateRequest;
	use TLSProxy::CertificateVerify;
	use TLSProxy::ServerKeyExchange;
	use TLSProxy::NewSessionTicket;

	my $have_IPv6;
	my $IP_factory;

	BEGIN
	{
	# IO::Socket::IP is on the core module list, IO::Socket::INET6 isn't.
	# However, IO::Socket::INET6 is older and is said to be more widely
	# deployed for the moment, and may have less bugs, so we try the latter
	# first, then fall back on the core modules. Worst case scenario, we
	# fall back to IO::Socket::INET, only supports IPv4.
	eval {
	require IO::Socket::INET6;
	my $s = IO::Socket::INET6->new(
	LocalAddr => "::1",
	LocalPort => 0,
	Listen=>1,
	);
	$s or die "\n";
	$s->close();
	};
	if ($@ eq "") {
	$IP_factory = sub { IO::Socket::INET6->new(Domain => AF_INET6, @_); };
	$have_IPv6 = 1;
	} else {
	eval {
	require IO::Socket::IP;
	my $s = IO::Socket::IP->new(
	LocalAddr => "::1",
	LocalPort => 0,
	Listen=>1,
	);
	$s or die "\n";
	$s->close();
	};
	if ($@ eq "") {
	$IP_factory = sub { IO::Socket::IP->new(@_); };
	$have_IPv6 = 1;
	} else {
	$IP_factory = sub { IO::Socket::INET->new(@_); };
	$have_IPv6 = 0;
	}
	}
	}

	my $is_tls13 = 0;
	my $ciphersuite = undef;

	sub new
	{
	my $class = shift;
	my ($filter,
	$execute,
	$cert,
	$debug) = @_;

	my $self = {
	#Public read/write
	proxy_addr => $have_IPv6 ? "[::1]" : "127.0.0.1",
	filter => $filter,
	serverflags => "",
	clientflags => "",
	serverconnects => 1,
	reneg => 0,
	sessionfile => undef,

	#Public read
	proxy_port => 0,
	server_port => 0,
	serverpid => 0,
	clientpid => 0,
	execute => $execute,
	cert => $cert,
	debug => $debug,
	cipherc => "",
	ciphersuitesc => "",
	ciphers => "AES128-SHA",
	ciphersuitess => "TLS_AES_128_GCM_SHA256",
	flight => -1,
	direction => -1,
	partial => ["", ""],
	record_list => [],
	message_list => [],
	};

	# Create the Proxy socket
	my $proxaddr = $self->{proxy_addr};
	$proxaddr =~ s/[\[\]]//g; # Remove [ and ]
	my @proxyargs = (
	LocalHost => $proxaddr,
	LocalPort => 0,
	Proto => "tcp",
	Listen => SOMAXCONN,
	);

	if (my $sock = $IP_factory->(@proxyargs)) {
	$self->{proxy_sock} = $sock;
	$self->{proxy_port} = $sock->sockport();
	$self->{proxy_addr} = $sock->sockhost();
	$self->{proxy_addr} =~ s/(.:.)/[$1]/;
	print "Proxy started on port ",
	"$self->{proxy_addr}:$self->{proxy_port}\n";
	# use same address for s_server
	$self->{server_addr} = $self->{proxy_addr};
	} else {
	warn "Failed creating proxy socket (".$proxaddr.",0): $!\n";
	}

	return bless $self, $class;
	}

	sub DESTROY
	{
	my $self = shift;

	$self->{proxy_sock}->close() if $self->{proxy_sock};
	}

	sub clearClient
	{
	my $self = shift;

	$self->{cipherc} = "";
	$self->{ciphersuitec} = "";
	$self->{flight} = -1;
	$self->{direction} = -1;
	$self->{partial} = ["", ""];
	$self->{record_list} = [];
	$self->{message_list} = [];
	$self->{clientflags} = "";
	$self->{sessionfile} = undef;
	$self->{clientpid} = 0;
	$is_tls13 = 0;
	$ciphersuite = undef;

	TLSProxy::Message->clear();
	TLSProxy::Record->clear();
	}

	sub clear
	{
	my $self = shift;

	$self->clearClient;
	$self->{ciphers} = "AES128-SHA";
	$self->{ciphersuitess} = "TLS_AES_128_GCM_SHA256";
	$self->{serverflags} = "";
	$self->{serverconnects} = 1;
	$self->{serverpid} = 0;
	$self->{reneg} = 0;
	}

	sub restart
	{
	my $self = shift;

	$self->clear;
	$self->start;
	}

	sub clientrestart
	{
	my $self = shift;

	$self->clear;
	$self->clientstart;
	}

	sub connect_to_server
	{
	my $self = shift;
	my $servaddr = $self->{server_addr};

	$servaddr =~ s/[\[\]]//g; # Remove [ and ]

	my $sock = $IP_factory->(PeerAddr => $servaddr,
	PeerPort => $self->{server_port},
	Proto => 'tcp');
	if (!defined($sock)) {
	my $err = $!;
	kill(3, $self->{real_serverpid});
	die "unable to connect: $err\n";
	}

	$self->{server_sock} = $sock;
	}

	sub start
	{
	my ($self) = shift;
	my $pid;

	if ($self->{proxy_sock} == 0) {
	return 0;
	}

	my $execcmd = $self->execute
	." s_server -max_protocol TLSv1.3 -no_comp -rev -engine ossltest"
	#In TLSv1.3 we issue two session tickets. The default session id
	#callback gets confused because the ossltest engine causes the same
	#session id to be created twice due to the changed random number
	#generation. Using "-ext_cache" replaces the default callback with a
	#different one that doesn't get confused.
	." -ext_cache"
	." -accept $self->{server_addr}:0"
	." -cert ".$self->cert." -cert2 ".$self->cert
	." -naccept ".$self->serverconnects;
	if ($self->ciphers ne "") {
	$execcmd .= " -cipher ".$self->ciphers;
	}
	if ($self->ciphersuitess ne "") {
	$execcmd .= " -ciphersuites ".$self->ciphersuitess;
	}
	if ($self->serverflags ne "") {
	$execcmd .= " ".$self->serverflags;
	}
	if ($self->debug) {
	print STDERR "Server command: $execcmd\n";
	}

	open(my $savedin, "<&STDIN");

	# Temporarily replace STDIN so that sink process can inherit it...
	$pid = open(STDIN, "$execcmd 2>&1 \|") or die "Failed to $execcmd: $!\n";
	$self->{real_serverpid} = $pid;

	# Process the output from s_server until we find the ACCEPT line, which
	# tells us what the accepting address and port are.
	while (<>) {
	print;
	s/\R$//; # Better chomp
	next unless (/^ACCEPT\s.*:(\d+)$/);
	$self->{server_port} = $1;
	last;
	}

	if ($self->{server_port} == 0) {
	# This actually means that s_server exited, because otherwise
	# we would still searching for ACCEPT...
	waitpid($pid, 0);
	die "no ACCEPT detected in '$execcmd' output: $?\n";
	}

	# Just make sure everything else is simply printed [as separate lines].
	# The sub process simply inherits our STD* and will keep consuming
	# server's output and printing it as long as there is anything there,
	# out of our way.
	my $error;
	$pid = undef;
	if (eval { require Win32::Process; 1; }) {
	if (Win32::Process::Create(my $h, $^X, "perl -ne print", 0, 0, ".")) {
	$pid = $h->GetProcessID();
	$self->{proc_handle} = $h; # hold handle till next round [or exit]
	} else {
	$error = Win32::FormatMessage(Win32::GetLastError());
	}
	} else {
	if (defined($pid = fork)) {
	$pid or exec("$^X -ne print") or exit($!);
	} else {
	$error = $!;
	}
	}

	# Change back to original stdin
	open(STDIN, "<&", $savedin);
	close($savedin);

	if (!defined($pid)) {
	kill(3, $self->{real_serverpid});
	die "Failed to capture s_server's output: $error\n";
	}

	$self->{serverpid} = $pid;

	print STDERR "Server responds on ",
	"$self->{server_addr}:$self->{server_port}\n";

	# Connect right away...
	$self->connect_to_server();

	return $self->clientstart;
	}

	sub clientstart
	{
	my ($self) = shift;

	if ($self->execute) {
	my $pid;
	my $execcmd = $self->execute
	." s_client -max_protocol TLSv1.3 -engine ossltest"
	." -connect $self->{proxy_addr}:$self->{proxy_port}";
	if ($self->cipherc ne "") {
	$execcmd .= " -cipher ".$self->cipherc;
	}
	if ($self->ciphersuitesc ne "") {
	$execcmd .= " -ciphersuites ".$self->ciphersuitesc;
	}
	if ($self->clientflags ne "") {
	$execcmd .= " ".$self->clientflags;
	}
	if ($self->clientflags !~ m/-(no)?servername/) {
	$execcmd .= " -servername localhost";
	}
	if (defined $self->sessionfile) {
	$execcmd .= " -ign_eof";
	}
	if ($self->debug) {
	print STDERR "Client command: $execcmd\n";
	}

	open(my $savedout, ">&STDOUT");
	# If we open pipe with new descriptor, attempt to close it,
	# explicitly or implicitly, would incur waitpid and effectively
	# dead-lock...
	if (!($pid = open(STDOUT, "\| $execcmd"))) {
	my $err = $!;
	kill(3, $self->{real_serverpid});
	die "Failed to $execcmd: $err\n";
	}
	$self->{clientpid} = $pid;

	# queue [magic] input
	print $self->reneg ? "R" : "test";

	# this closes client's stdin without waiting for its pid
	open(STDOUT, ">&", $savedout);
	close($savedout);
	}

	# Wait for incoming connection from client
	my $fdset = IO::Select->new($self->{proxy_sock});
	if (!$fdset->can_read(60)) {
	kill(3, $self->{real_serverpid});
	die "s_client didn't try to connect\n";
	}

	my $client_sock;
	if(!($client_sock = $self->{proxy_sock}->accept())) {
	warn "Failed accepting incoming connection: $!\n";
	return 0;
	}

	print "Connection opened\n";

	my $server_sock = $self->{server_sock};
	my $indata;

	#Wait for either the server socket or the client socket to become readable
	$fdset = IO::Select->new($server_sock, $client_sock);
	my @ready;
	my $ctr = 0;
	local $SIG{PIPE} = "IGNORE";
	$self->{saw_session_ticket} = undef;
	while($fdset->count && $ctr < 10) {
	if (defined($self->{sessionfile})) {
	# s_client got -ign_eof and won't be exiting voluntarily, so we
	# look for data and session ticket...
	last if TLSProxy::Message->success()
	&& $self->{saw_session_ticket};
	}
	if (!(@ready = $fdset->can_read(1))) {
	$ctr++;
	next;
	}
	foreach my $hand (@ready) {
	if ($hand == $server_sock) {
	if ($server_sock->sysread($indata, 16384)) {
	if ($indata = $self->process_packet(1, $indata)) {
	$client_sock->syswrite($indata) or goto END;
	}
	$ctr = 0;
	} else {
	$fdset->remove($server_sock);
	$client_sock->shutdown(SHUT_WR);
	}
	} elsif ($hand == $client_sock) {
	if ($client_sock->sysread($indata, 16384)) {
	if ($indata = $self->process_packet(0, $indata)) {
	$server_sock->syswrite($indata) or goto END;
	}
	$ctr = 0;
	} else {
	$fdset->remove($client_sock);
	$server_sock->shutdown(SHUT_WR);
	}
	} else {
	kill(3, $self->{real_serverpid});
	die "Unexpected handle";
	}
	}
	}

	if ($ctr >= 10) {
	kill(3, $self->{real_serverpid});
	die "No progress made";
	}

	END:
	print "Connection closed\n";
	if($server_sock) {
	$server_sock->close();
	$self->{server_sock} = undef;
	}
	if($client_sock) {
	#Closing this also kills the child process
	$client_sock->close();
	}

	my $pid;
	if (--$self->{serverconnects} == 0) {
	$pid = $self->{serverpid};
	print "Waiting for 'perl -ne print' process to close: $pid...\n";
	$pid = waitpid($pid, 0);
	if ($pid > 0) {
	die "exit code $? from 'perl -ne print' process\n" if $? != 0;
	} elsif ($pid == 0) {
	kill(3, $self->{real_serverpid});
	die "lost control over $self->{serverpid}?";
	}
	$pid = $self->{real_serverpid};
	print "Waiting for s_server process to close: $pid...\n";
	# it's done already, just collect the exit code [and reap]...
	waitpid($pid, 0);
	die "exit code $? from s_server process\n" if $? != 0;
	} else {
	# It's a bit counter-intuitive spot to make next connection to
	# the s_server. Rationale is that established connection works
	# as synchronization point, in sense that this way we know that
	# s_server is actually done with current session...
	$self->connect_to_server();
	}
	$pid = $self->{clientpid};
	print "Waiting for s_client process to close: $pid...\n";
	waitpid($pid, 0);

	return 1;
	}

	sub process_packet
	{
	my ($self, $server, $packet) = @_;
	my $len_real;
	my $decrypt_len;
	my $data;
	my $recnum;

	if ($server) {
	print "Received server packet\n";
	} else {
	print "Received client packet\n";
	}

	if ($self->{direction} != $server) {
	$self->{flight} = $self->{flight} + 1;
	$self->{direction} = $server;
	}

	print "Packet length = ".length($packet)."\n";
	print "Processing flight ".$self->flight."\n";

	#Return contains the list of record found in the packet followed by the
	#list of messages in those records and any partial message
	my @ret = TLSProxy::Record->get_records($server, $self->flight,
	$self->{partial}[$server].$packet);
	$self->{partial}[$server] = $ret[2];
	push @{$self->{record_list}}, @{$ret[0]};
	push @{$self->{message_list}}, @{$ret[1]};

	print "\n";

	if (scalar(@{$ret[0]}) == 0 or length($ret[2]) != 0) {
	return "";
	}

	#Finished parsing. Call user provided filter here
	if (defined $self->filter) {
	$self->filter->($self);
	}

	#Take a note on NewSessionTicket
	foreach my $message (reverse @{$self->{message_list}}) {
	if ($message->{mt} == TLSProxy::Message::MT_NEW_SESSION_TICKET) {
	$self->{saw_session_ticket} = 1;
	last;
	}
	}

	#Reconstruct the packet
	$packet = "";
	foreach my $record (@{$self->record_list}) {
	$packet .= $record->reconstruct_record($server);
	}

	print "Forwarded packet length = ".length($packet)."\n\n";

	return $packet;
	}

	#Read accessors
	sub execute
	{
	my $self = shift;
	return $self->{execute};
	}
	sub cert
	{
	my $self = shift;
	return $self->{cert};
	}
	sub debug
	{
	my $self = shift;
	return $self->{debug};
	}
	sub flight
	{
	my $self = shift;
	return $self->{flight};
	}
	sub record_list
	{
	my $self = shift;
	return $self->{record_list};
	}
	sub success
	{
	my $self = shift;
	return $self->{success};
	}
	sub end
	{
	my $self = shift;
	return $self->{end};
	}
	sub supports_IPv6
	{
	my $self = shift;
	return $have_IPv6;
	}
	sub proxy_addr
	{
	my $self = shift;
	return $self->{proxy_addr};
	}
	sub proxy_port
	{
	my $self = shift;
	return $self->{proxy_port};
	}
	sub server_addr
	{
	my $self = shift;
	return $self->{server_addr};
	}
	sub server_port
	{
	my $self = shift;
	return $self->{server_port};
	}
	sub serverpid
	{
	my $self = shift;
	return $self->{serverpid};
	}
	sub clientpid
	{
	my $self = shift;
	return $self->{clientpid};
	}

	#Read/write accessors
	sub filter
	{
	my $self = shift;
	if (@_) {
	$self->{filter} = shift;
	}
	return $self->{filter};
	}
	sub cipherc
	{
	my $self = shift;
	if (@_) {
	$self->{cipherc} = shift;
	}
	return $self->{cipherc};
	}
	sub ciphersuitesc
	{
	my $self = shift;
	if (@_) {
	$self->{ciphersuitesc} = shift;
	}
	return $self->{ciphersuitesc};
	}
	sub ciphers
	{
	my $self = shift;
	if (@_) {
	$self->{ciphers} = shift;
	}
	return $self->{ciphers};
	}
	sub ciphersuitess
	{
	my $self = shift;
	if (@_) {
	$self->{ciphersuitess} = shift;
	}
	return $self->{ciphersuitess};
	}
	sub serverflags
	{
	my $self = shift;
	if (@_) {
	$self->{serverflags} = shift;
	}
	return $self->{serverflags};
	}
	sub clientflags
	{
	my $self = shift;
	if (@_) {
	$self->{clientflags} = shift;
	}
	return $self->{clientflags};
	}
	sub serverconnects
	{
	my $self = shift;
	if (@_) {
	$self->{serverconnects} = shift;
	}
	return $self->{serverconnects};
	}
	# This is a bit ugly because the caller is responsible for keeping the records
	# in sync with the updated message list; simply updating the message list isn't
	# sufficient to get the proxy to forward the new message.
	# But it does the trick for the one test (test_sslsessiontick) that needs it.
	sub message_list
	{
	my $self = shift;
	if (@_) {
	$self->{message_list} = shift;
	}
	return $self->{message_list};
	}

	sub fill_known_data
	{
	my $length = shift;
	my $ret = "";
	for (my $i = 0; $i < $length; $i++) {
	$ret .= chr($i);
	}
	return $ret;
	}

	sub is_tls13
	{
	my $class = shift;
	if (@_) {
	$is_tls13 = shift;
	}
	return $is_tls13;
	}

	sub reneg
	{
	my $self = shift;
	if (@_) {
	$self->{reneg} = shift;
	}
	return $self->{reneg};
	}

	#Setting a sessionfile means that the client will not close until the given
	#file exists. This is useful in TLSv1.3 where otherwise s_client will close
	#immediately at the end of the handshake, but before the session has been
	#received from the server. A side effect of this is that s_client never sends
	#a close_notify, so instead we consider success to be when it sends application
	#data over the connection.
	sub sessionfile
	{
	my $self = shift;
	if (@_) {
	$self->{sessionfile} = shift;
	TLSProxy::Message->successondata(1);
	}
	return $self->{sessionfile};
	}

	sub ciphersuite
	{
	my $class = shift;
	if (@_) {
	$ciphersuite = shift;
	}
	return $ciphersuite;
	}

	1;