AnyEvent-MP/MP/Transport.pm

=head1 NAME

AnyEvent::MP::Transport - actual transport protocol handler

=head1 SYNOPSIS

   use AnyEvent::MP::Transport;

=head1 DESCRIPTION

This implements the actual transport protocol for MP (it represents a
single link), most of which is considered an implementation detail.

See the "PROTOCOL" section below if you want to write another client for
this protocol.

=head1 FUNCTIONS/METHODS

=over 4

=cut

package AnyEvent::MP::Transport;

use common::sense;

use Scalar::Util;
use MIME::Base64 ();
use Storable ();
use JSON::XS ();

use Digest::MD6 ();
use Digest::HMAC_MD6 ();

use AE ();
use AnyEvent::Socket ();
use AnyEvent::Handle ();

use base Exporter::;

our $VERSION = '0.0';
our $PROTOCOL_VERSION = 0;

=item $listener = mp_listener $host, $port, <constructor-args>, $cb->($transport)

Creates a listener on the given host/port using
C<AnyEvent::Socket::tcp_server>.

See C<new>, below, for constructor arguments.

Defaults for peerhost, peerport and fh are provided.

=cut

sub mp_server($$@) {
   my $cb = pop;
   my ($host, $port, @args) = @_;

   AnyEvent::Socket::tcp_server $host, $port, sub {
      my ($fh, $host, $port) = @_;

      $cb->(new AnyEvent::MP::Transport
         fh       => $fh,
         peerhost => $host,
         peerport => $port,
         @args,
      );
   }
}

=item $guard = mp_connect $host, $port, <constructor-args>, $cb->($transport)

=cut

sub mp_connect {
   my $cb = pop;
   my ($host, $port, @args) = @_;

   AnyEvent::Socket::tcp_connect $host, $port, sub {
      my ($fh, $nhost, $nport) = @_;

      return $cb->() unless $fh;

      $cb->(new AnyEvent::MP::Transport
         fh       => $fh,
         peername => $host,
         peerhost => $nhost,
         peerport => $nport,
         @args,
      );
   }
}

=item new AnyEvent::MP::Transport

   # immediately starts negotiation
   my $transport = new AnyEvent::MP::Transport
      # mandatory
      fh       => $filehandle,
      local_id => $identifier,
      on_recv  => sub { receive-callback },
      on_error => sub { error-callback },

      # optional
      secret   => "shared secret",
      on_eof   => sub { clean-close-callback },
      on_connect => sub { successful-connect-callback },
      greeting => { key => value },

      # tls support
      tls_ctx  => AnyEvent::TLS,
      peername => $peername, # for verification
   ;

=cut

our @FRAMINGS = qw(json storable); # the framing types we accept and send, in order of preference
our @AUTH_SND = qw(hmac_md6_64_256); # auth types we send
our @AUTH_RCV = (@AUTH_SND, qw(cleartext)); # auth types we accept

#AnyEvent::Handle::register_write_type mp_record => sub {
#};

sub new {
   my ($class, %arg) = @_;

   my $self = bless \%arg, $class;

   $self->{queue} = [];

   {
      Scalar::Util::weaken (my $self = $self);

      $arg{secret} = AnyEvent::MP::Base::default_secret ()
         unless exists $arg{secret};

      my $secret = $arg{secret};

      if ($secret =~ /-----BEGIN RSA PRIVATE KEY-----.*-----END RSA PRIVATE KEY-----.*-----BEGIN CERTIFICATE-----.*-----END CERTIFICATE-----/s) {
         # assume TLS mode
         $arg{tls_ctx} = {
            sslv2   => 0,
            sslv3   => 0,
            tlsv1   => 1,
            verify  => 1,
            cert    => $secret,
            ca_cert => $secret,
            verify_require_client_cert => 1,
         };
      }

      $self->{hdl} = new AnyEvent::Handle
         fh       => delete $arg{fh},
         autocork => 1,
         no_delay => 1,
         on_error => sub {
            $self->error ($_[2]);
         },
         peername => delete $arg{peername},
      ;

      my $greeting_kv = $self->{greeting} ||= {};
      $greeting_kv->{"tls"} = "1.0"
         if $arg{tls_ctx};
      $greeting_kv->{provider} = "AE-$VERSION";
      $greeting_kv->{peeraddr} = AnyEvent::Socket::format_hostport $self->{peerhost}, $self->{peerport};

      # send greeting
      my $lgreeting1 = "aemp;$PROTOCOL_VERSION"
                     . ";$AnyEvent::MP::Base::UNIQ"
                     . ";$AnyEvent::MP::Base::NODE"
                     . ";" . (join ",", @AUTH_RCV)
                     . ";" . (join ",", @FRAMINGS)
                     . (join "", map ";$_=$greeting_kv->{$_}", keys %$greeting_kv);

      my $lgreeting2 = MIME::Base64::encode_base64 AnyEvent::MP::Base::nonce (33), "";

      $self->{hdl}->push_write ("$lgreeting1\012$lgreeting2\012");

      # expect greeting
      $self->{hdl}->rbuf_max (4 * 1024);
      $self->{hdl}->push_read (line => sub {
         my $rgreeting1 = $_[1];

         my ($aemp, $version, $uniq, $rnode, $auths, $framings, @kv) = split /;/, $rgreeting1;

         if ($aemp ne "aemp") {
            return $self->error ("unparsable greeting");
         } elsif ($version != $PROTOCOL_VERSION) {
            return $self->error ("version mismatch (we: $PROTOCOL_VERSION, they: $version)");
         }

         my $s_auth;
         for my $auth_ (split /,/, $auths) {
            if (grep $auth_ eq $_, @AUTH_SND) {
               $s_auth = $auth_;
               last;
            }
         }

         defined $s_auth
            or return $self->error ("$auths: no common auth type supported");

         die unless $s_auth eq "hmac_md6_64_256"; # hardcoded atm.

         my $s_framing;
         for my $framing_ (split /,/, $framings) {
            if (grep $framing_ eq $_, @FRAMINGS) {
               $s_framing = $framing_;
               last;
            }
         }

         defined $s_framing
            or return $self->error ("$framings: no common framing method supported");

         $self->{remote_uniq} = $uniq;
         $self->{remote_node} = $rnode;

         $self->{remote_greeting} = {
            map /^([^=]+)(?:=(.*))?/ ? ($1 => $2) : (),
               @kv
         };

         # read nonce
         $self->{hdl}->push_read (line => sub {
            my $rgreeting2 = $_[1];

            "$lgreeting1\012$lgreeting2" ne "$rgreeting1\012$rgreeting2" # echo attack?
               or return $self->error ("authentication error, echo attack?");

            my $key = Digest::MD6::md6 $secret;
            my $lauth;

            if ($self->{tls_ctx} and 1 == int $self->{remote_greeting}{tls}) {
               $self->{tls} = $lgreeting2 lt $rgreeting2 ? "connect" : "accept";
               $self->{hdl}->starttls ($self->{tls}, $self->{tls_ctx});
               $s_auth = "tls";
               $lauth = "";
            } else {
               # we currently only support hmac_md6_64_256
               $lauth = Digest::HMAC_MD6::hmac_md6_hex $key, "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012", 64, 256;
            }

            $self->{hdl}->push_write ("$s_auth;$lauth;$s_framing\012");

            # read the authentication response
            $self->{hdl}->push_read (line => sub {
               my ($hdl, $rline) = @_;

               my ($auth_method, $rauth2, $r_framing) = split /;/, $rline;

               my $rauth =
                  $auth_method eq "hmac_md6_64_256" ? Digest::HMAC_MD6::hmac_md6_hex $key, "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012", 64, 256
                : $auth_method eq "cleartext"       ? unpack "H*", $secret
                : $auth_method eq "tls"             ? ($self->{tls} ? "" : "\012\012") # \012\012 never matches
                : return $self->error ("$auth_method: fatal, selected unsupported auth method");

               if ($rauth2 ne $rauth) {
                  return $self->error ("authentication failure/shared secret mismatch");
               }

               $self->{s_framing} = $s_framing;

               $hdl->rbuf_max (undef);
               my $queue = delete $self->{queue}; # we are connected

               $self->connected;

               my $src_node = $self->{node};

               $hdl->push_write ($self->{s_framing} => $_)
                  for @$queue;

               my $rmsg; $rmsg = sub  {
                  $_[0]->push_read ($r_framing => $rmsg);

                  local $AnyEvent::MP::Base::SRCNODE = $src_node;
                  AnyEvent::MP::Base::_inject (@{ $_[1] });
               };
               $hdl->push_read ($r_framing => $rmsg);
            });
         });
      });
   }

   $self
}

sub error {
   my ($self, $msg) = @_;

   if ($self->{node} && $self->{node}{transport} == $self) {
      #TODO: store error, but do not instantly fail
      $self->{node}->fail (transport_error => $self->{node}{noderef}, $msg);
      $self->{node}->clr_transport;
   }
   $AnyEvent::MP::Base::WARN->("$self->{peerhost}:$self->{peerport}: $msg");
   $self->destroy;
}

sub connected {
   my ($self) = @_;

   my $node = AnyEvent::MP::Base::add_node ($self->{remote_node});
   Scalar::Util::weaken ($self->{node} = $node);
   $node->set_transport ($self);
}

sub send {
   $_[0]{hdl}->push_write ($_[0]{s_framing} => $_[1]);
}

sub destroy {
   my ($self) = @_;

   $self->{hdl}->destroy
      if $self->{hdl};
}

sub DESTROY {
   my ($self) = @_;

   $self->destroy;
}

=back

=head1 PROTOCOL

The protocol is relatively simple, and consists of three phases which are
symmetrical for both sides: greeting (followed by optionally switching to
TLS mode), authentication and packet exchange.

the protocol is designed to allow both full-text and binary streams.

The greeting consists of two text lines that are ended by either an ASCII
CR LF pair, or a single ASCII LF (recommended).

=head2 GREETING

All the lines until after authentication must not exceed 4kb in length,
including delimiter. Afterwards there is no limit on the packet size that
can be received.

=head3 First Greeting Line

Example:

   aemp;0;fec.4a7720fc;127.0.0.1:1235,[::1]:1235;hmac_md6_64_256;json,storable;provider=AE-0.0

The first line contains strings separated (not ended) by C<;>
characters. The first even ixtrings are fixed by the protocol, the
remaining strings are C<KEY=VALUE> pairs. None of them may contain C<;>
characters themselves.

The fixed strings are:

=over 4

=item protocol identification

The constant C<aemp> to identify the protocol.

=item protocol version

The protocol version supported by this end, currently C<0>. If the
versions don't match then no communication is possible. Minor extensions
are supposed to be handled through additional key-value pairs.

=item a token uniquely identifying the current node instance

This is a string that must change between restarts. It usually contains
things like the current time, the (OS) process id or similar values, but
no meaning of the contents are assumed.

=item the node endpoint descriptors

for public nodes, this is a comma-separated list of protocol endpoints,
i.e., the noderef. For slave nodes, this is a unique identifier.

=item the acceptable authentication methods

A comma-separated list of authentication methods supported by the
node. Note that AnyEvent::MP supports a C<hex_secret> authentication
method that accepts a cleartext password (hex-encoded), but will not use
this auth method itself.

The receiving side should choose the first auth method it supports.

=item the acceptable framing formats

A comma-separated list of packet encoding/framign formats understood. The
receiving side should choose the first framing format it supports for
sending packets (which might be different from the format it has to accept).

=back

The remaining arguments are C<KEY=VALUE> pairs. The following key-value
pairs are known at this time:

=over 4

=item provider=<module-version>

The software provider for this implementation. For AnyEvent::MP, this is
C<AE-0.0> or whatever version it currently is at.

=item peeraddr=<host>:<port>

The peer address (socket address of the other side) as seen locally, in the same format
as noderef endpoints.

=item tls=<major>.<minor>

Indicates that the other side supports TLS (version should be 1.0) and
wishes to do a TLS handshake.

=back

=head3 Second Greeting Line

After this greeting line there will be a second line containing a
cryptographic nonce, i.e. random data of high quality. To keep the
protocol text-only, these are usually 32 base64-encoded octets, but
it could be anything that doesn't contain any ASCII CR or ASCII LF
characters.

I<< The two nonces B<must> be different, and an aemp implementation
B<must> check and fail when they are identical >>.

Example of a nonce line:

   p/I122ql7kJR8lumW3lXlXCeBnyDAvz8NQo3x5IFowE4

=head2 TLS handshake

I<< If, after the handshake, both sides indicate interest in TLS, then the
connection B<must> use TLS, or fail. >>

Both sides compare their nonces, and the side who sent the lower nonce
value ("string" comparison on the raw octet values) becomes the client,
and the one with the higher nonce the server.

=head2 AUTHENTICATION PHASE

After the greeting is received (and the optional TLS handshake),
the authentication phase begins, which consists of sending a single
C<;>-separated line with three fixed strings and any number of
C<KEY=VALUE> pairs.

The three fixed strings are:

=over 4

=item the authentication method chosen

This must be one of the methods offered by the other side in the greeting.

The currently supported authentication methods are:

=over 4

=item cleartext

This is simply the shared secret, lowercase-hex-encoded. This method is of
course very insecure, unless TLS is used, which is why this module will
accept, but not generate, cleartext auth replies.

=item hmac_md6_64_256

This method uses an MD6 HMAC with 64 bit blocksize and 256 bit hash. First, the shared secret
is hashed with MD6:

   key = MD6 (secret)

This secret is then used to generate the "local auth reply", by taking
the two local greeting lines and the two remote greeting lines (without
line endings), appending \012 to all of them, concatenating them and
calculating the MD6 HMAC with the key.

   lauth = HMAC_MD6 key, "lgreeting1\012lgreeting2\012rgreeting1\012rgreeting2\012"

This authentication token is then lowercase-hex-encoded and sent to the
other side.

Then the remote auth reply is generated using the same method, but local
and remote greeting lines swapped:

   rauth = HMAC_MD6 key, "rgreeting1\012rgreeting2\012lgreeting1\012lgreeting2\012"

This is the token that is expected from the other side.

=item tls

This type is only valid iff TLS was enabled and the TLS handshake
was successful. It has no authentication data, as the server/client
certificate was successfully verified.

Implementations supporting TLS I<must> accept this authentication type.

=back

=item the authentication data

The authentication data itself, usually base64 or hex-encoded data, see
above.

=item the framing protocol chosen

This must be one of the framing protocols offered by the other side in the
greeting. Each side must accept the choice of the other side.

=back

Example of an authentication reply:

   hmac_md6_64_256;363d5175df38bd9eaddd3f6ca18aa1c0c4aa22f0da245ac638d048398c26b8d3;json

=head2 DATA PHASE

After this, packets get exchanged using the chosen framing protocol. It is
quite possible that both sides use a different framing protocol.

=head2 FULL EXAMPLE

This is an actual protocol dump of a handshake, followed by a single data
packet. The greater than/less than lines indicate the direction of the
transfer only.

   > aemp;0;nndKd+gn;10.0.0.1:4040;hmac_md6_64_256,cleartext;json,storable;provider=AE-0.0;peeraddr=127.0.0.1:1235
   > sRG8bbc4TDbkpvH8FTP4HBs87OhepH6VuApoZqXXskuG
   < aemp;0;nmpKd+gh;127.0.0.1:1235,[::1]:1235;hmac_md6_64_256,cleartext;json,storable;provider=AE-0.0;peeraddr=127.0.0.1:58760
   < dCEUcL/LJVSTJcx8byEsOzrwhzJYOq+L3YcopA5T6EAo
   > hmac_md6_64_256;9513d4b258975accfcb2ab7532b83690e9c119a502c612203332a591c7237788;json
   < hmac_md6_64_256;0298d6ba2240faabb2b2e881cf86b97d70a113ca74a87dc006f9f1e9d3010f90;json
   > ["","lookup","pinger","10.0.0.1:4040#nndKd+gn.a","resolved"]

=head1 SEE ALSO

L<AnyEvent>.

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

1

Revision:	1.21
Committed:	Tue Aug 4 23:35:51 2009 UTC (14 years, 9 months ago) by root
Branch:	MAIN
Changes since 1.20:	+2 -1 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3	root	1.13	AnyEvent::MP::Transport - actual transport protocol handler
4	root	1.1
5			=head1 SYNOPSIS
6
7			use AnyEvent::MP::Transport;
8
9			=head1 DESCRIPTION
10
11	root	1.13	This implements the actual transport protocol for MP (it represents a
12			single link), most of which is considered an implementation detail.
13	root	1.1
14	root	1.7	See the "PROTOCOL" section below if you want to write another client for
15			this protocol.
16	root	1.1
17			=head1 FUNCTIONS/METHODS
18
19			=over 4
20
21			=cut
22
23			package AnyEvent::MP::Transport;
24
25			use common::sense;
26
27			use Scalar::Util;
28			use MIME::Base64 ();
29			use Storable ();
30	root	1.2	use JSON::XS ();
31	root	1.1
32	root	1.19	use Digest::MD6 ();
33			use Digest::HMAC_MD6 ();
34
35	root	1.1	use AE ();
36			use AnyEvent::Socket ();
37			use AnyEvent::Handle ();
38	root	1.2
39	root	1.1	use base Exporter::;
40
41			our $VERSION = '0.0';
42	root	1.2	our $PROTOCOL_VERSION = 0;
43	root	1.1
44			=item $listener = mp_listener $host, $port, <constructor-args>, $cb->($transport)
45
46			Creates a listener on the given host/port using
47			C<AnyEvent::Socket::tcp_server>.
48
49			See C<new>, below, for constructor arguments.
50
51	root	1.10	Defaults for peerhost, peerport and fh are provided.
52	root	1.1
53			=cut
54
55			sub mp_server($$@) {
56			my $cb = pop;
57			my ($host, $port, @args) = @_;
58
59			AnyEvent::Socket::tcp_server $host, $port, sub {
60			my ($fh, $host, $port) = @_;
61
62			$cb->(new AnyEvent::MP::Transport
63			fh => $fh,
64			peerhost => $host,
65			peerport => $port,
66			@args,
67			);
68			}
69			}
70
71	root	1.2	=item $guard = mp_connect $host, $port, <constructor-args>, $cb->($transport)
72
73			=cut
74
75			sub mp_connect {
76			my $cb = pop;
77			my ($host, $port, @args) = @_;
78
79			AnyEvent::Socket::tcp_connect $host, $port, sub {
80			my ($fh, $nhost, $nport) = @_;
81
82			return $cb->() unless $fh;
83
84			$cb->(new AnyEvent::MP::Transport
85			fh => $fh,
86			peername => $host,
87			peerhost => $nhost,
88			peerport => $nport,
89			@args,
90			);
91			}
92			}
93
94	root	1.1	=item new AnyEvent::MP::Transport
95
96			# immediately starts negotiation
97			my $transport = new AnyEvent::MP::Transport
98	root	1.2	# mandatory
99	root	1.1	fh => $filehandle,
100	root	1.2	local_id => $identifier,
101	root	1.1	on_recv => sub { receive-callback },
102			on_error => sub { error-callback },
103
104			# optional
105			secret => "shared secret",
106			on_eof => sub { clean-close-callback },
107			on_connect => sub { successful-connect-callback },
108	root	1.2	greeting => { key => value },
109	root	1.1
110			# tls support
111			tls_ctx => AnyEvent::TLS,
112			peername => $peername, # for verification
113			;
114
115			=cut
116
117	root	1.7	our @FRAMINGS = qw(json storable); # the framing types we accept and send, in order of preference
118			our @AUTH_SND = qw(hmac_md6_64_256); # auth types we send
119	root	1.13	our @AUTH_RCV = (@AUTH_SND, qw(cleartext)); # auth types we accept
120	root	1.7
121			#AnyEvent::Handle::register_write_type mp_record => sub {
122			#};
123	root	1.4
124	root	1.1	sub new {
125			my ($class, %arg) = @_;
126
127			my $self = bless \%arg, $class;
128
129			$self->{queue} = [];
130
131			{
132			Scalar::Util::weaken (my $self = $self);
133
134	root	1.5	$arg{secret} = AnyEvent::MP::Base::default_secret ()
135	root	1.2	unless exists $arg{secret};
136
137	root	1.19	my $secret = $arg{secret};
138
139			if ($secret =~ /-----BEGIN RSA PRIVATE KEY-----.-----END RSA PRIVATE KEY-----.-----BEGIN CERTIFICATE-----.*-----END CERTIFICATE-----/s) {
140			# assume TLS mode
141			$arg{tls_ctx} = {
142			sslv2 => 0,
143			sslv3 => 0,
144			tlsv1 => 1,
145			verify => 1,
146			cert => $secret,
147			ca_cert => $secret,
148			verify_require_client_cert => 1,
149			};
150			}
151
152	root	1.1	$self->{hdl} = new AnyEvent::Handle
153	root	1.2	fh => delete $arg{fh},
154	root	1.4	autocork => 1,
155			no_delay => 1,
156	root	1.1	on_error => sub {
157			$self->error ($_[2]);
158			},
159			peername => delete $arg{peername},
160			;
161
162	root	1.2	my $greeting_kv = $self->{greeting} \|\|= {};
163	root	1.8	$greeting_kv->{"tls"} = "1.0"
164			if $arg{tls_ctx};
165	root	1.2	$greeting_kv->{provider} = "AE-$VERSION";
166	root	1.7	$greeting_kv->{peeraddr} = AnyEvent::Socket::format_hostport $self->{peerhost}, $self->{peerport};
167	root	1.1
168			# send greeting
169	root	1.12	my $lgreeting1 = "aemp;$PROTOCOL_VERSION"
170	root	1.7	. ";$AnyEvent::MP::Base::UNIQ"
171			. ";$AnyEvent::MP::Base::NODE"
172			. ";" . (join ",", @AUTH_RCV)
173			. ";" . (join ",", @FRAMINGS)
174			. (join "", map ";$_=$greeting_kv->{$_}", keys %$greeting_kv);
175	root	1.12
176	root	1.7	my $lgreeting2 = MIME::Base64::encode_base64 AnyEvent::MP::Base::nonce (33), "";
177	root	1.1
178	root	1.7	$self->{hdl}->push_write ("$lgreeting1\012$lgreeting2\012");
179	root	1.1
180			# expect greeting
181	root	1.12	$self->{hdl}->rbuf_max (4 * 1024);
182	root	1.1	$self->{hdl}->push_read (line => sub {
183	root	1.7	my $rgreeting1 = $_[1];
184	root	1.1
185	root	1.12	my ($aemp, $version, $uniq, $rnode, $auths, $framings, @kv) = split /;/, $rgreeting1;
186	root	1.1
187			if ($aemp ne "aemp") {
188			return $self->error ("unparsable greeting");
189	root	1.12	} elsif ($version != $PROTOCOL_VERSION) {
190			return $self->error ("version mismatch (we: $PROTOCOL_VERSION, they: $version)");
191	root	1.1	}
192
193	root	1.7	my $s_auth;
194			for my $auth_ (split /,/, $auths) {
195			if (grep $auth_ eq $_, @AUTH_SND) {
196			$s_auth = $auth_;
197			last;
198			}
199			}
200
201			defined $s_auth
202			or return $self->error ("$auths: no common auth type supported");
203
204			die unless $s_auth eq "hmac_md6_64_256"; # hardcoded atm.
205
206			my $s_framing;
207			for my $framing_ (split /,/, $framings) {
208			if (grep $framing_ eq $_, @FRAMINGS) {
209			$s_framing = $framing_;
210			last;
211			}
212			}
213
214			defined $s_framing
215			or return $self->error ("$framings: no common framing method supported");
216
217	root	1.2	$self->{remote_uniq} = $uniq;
218			$self->{remote_node} = $rnode;
219	root	1.1
220	root	1.2	$self->{remote_greeting} = {
221			map /^([^=]+)(?:=(.*))?/ ? ($1 => $2) : (),
222			@kv
223	root	1.1	};
224
225	root	1.7	# read nonce
226			$self->{hdl}->push_read (line => sub {
227			my $rgreeting2 = $_[1];
228
229	root	1.19	"$lgreeting1\012$lgreeting2" ne "$rgreeting1\012$rgreeting2" # echo attack?
230			or return $self->error ("authentication error, echo attack?");
231
232			my $key = Digest::MD6::md6 $secret;
233			my $lauth;
234
235	root	1.10	if ($self->{tls_ctx} and 1 == int $self->{remote_greeting}{tls}) {
236	root	1.8	$self->{tls} = $lgreeting2 lt $rgreeting2 ? "connect" : "accept";
237			$self->{hdl}->starttls ($self->{tls}, $self->{tls_ctx});
238	root	1.19	$s_auth = "tls";
239			$lauth = "";
240			} else {
241			# we currently only support hmac_md6_64_256
242			$lauth = Digest::HMAC_MD6::hmac_md6_hex $key, "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012", 64, 256;
243	root	1.8	}
244	root	1.2
245	root	1.7	$self->{hdl}->push_write ("$s_auth;$lauth;$s_framing\012");
246	root	1.2
247	root	1.19	# read the authentication response
248	root	1.7	$self->{hdl}->push_read (line => sub {
249			my ($hdl, $rline) = @_;
250	root	1.2
251	root	1.7	my ($auth_method, $rauth2, $r_framing) = split /;/, $rline;
252	root	1.1
253	root	1.19	my $rauth =
254			$auth_method eq "hmac_md6_64_256" ? Digest::HMAC_MD6::hmac_md6_hex $key, "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012", 64, 256
255			: $auth_method eq "cleartext" ? unpack "H*", $secret
256			: $auth_method eq "tls" ? ($self->{tls} ? "" : "\012\012") # \012\012 never matches
257			: return $self->error ("$auth_method: fatal, selected unsupported auth method");
258
259	root	1.7	if ($rauth2 ne $rauth) {
260			return $self->error ("authentication failure/shared secret mismatch");
261			}
262	root	1.1
263	root	1.7	$self->{s_framing} = $s_framing;
264	root	1.2
265	root	1.7	$hdl->rbuf_max (undef);
266			my $queue = delete $self->{queue}; # we are connected
267	root	1.1
268	root	1.7	$self->connected;
269	root	1.1
270	root	1.12	my $src_node = $self->{node};
271
272	root	1.7	$hdl->push_write ($self->{s_framing} => $_)
273			for @$queue;
274	root	1.1
275	root	1.7	my $rmsg; $rmsg = sub {
276			$_[0]->push_read ($r_framing => $rmsg);
277	root	1.1
278	root	1.12	local $AnyEvent::MP::Base::SRCNODE = $src_node;
279			AnyEvent::MP::Base::_inject (@{ $_[1] });
280	root	1.7	};
281			$hdl->push_read ($r_framing => $rmsg);
282			});
283	root	1.1	});
284			});
285			}
286
287			$self
288			}
289
290			sub error {
291			my ($self, $msg) = @_;
292
293	root	1.4	if ($self->{node} && $self->{node}{transport} == $self) {
294	root	1.21	#TODO: store error, but do not instantly fail
295			$self->{node}->fail (transport_error => $self->{node}{noderef}, $msg);
296	root	1.4	$self->{node}->clr_transport;
297			}
298	root	1.7	$AnyEvent::MP::Base::WARN->("$self->{peerhost}:$self->{peerport}: $msg");
299	root	1.4	$self->destroy;
300	root	1.1	}
301
302	root	1.2	sub connected {
303			my ($self) = @_;
304
305	root	1.5	my $node = AnyEvent::MP::Base::add_node ($self->{remote_node});
306	root	1.4	Scalar::Util::weaken ($self->{node} = $node);
307			$node->set_transport ($self);
308	root	1.2	}
309
310	root	1.1	sub send {
311	root	1.2	$_[0]{hdl}->push_write ($_[0]{s_framing} => $_[1]);
312	root	1.1	}
313
314			sub destroy {
315			my ($self) = @_;
316
317	root	1.2	$self->{hdl}->destroy
318			if $self->{hdl};
319	root	1.1	}
320
321			sub DESTROY {
322			my ($self) = @_;
323
324			$self->destroy;
325			}
326
327			=back
328
329	root	1.7	=head1 PROTOCOL
330
331			The protocol is relatively simple, and consists of three phases which are
332			symmetrical for both sides: greeting (followed by optionally switching to
333			TLS mode), authentication and packet exchange.
334
335			the protocol is designed to allow both full-text and binary streams.
336
337			The greeting consists of two text lines that are ended by either an ASCII
338			CR LF pair, or a single ASCII LF (recommended).
339
340			=head2 GREETING
341
342	root	1.15	All the lines until after authentication must not exceed 4kb in length,
343			including delimiter. Afterwards there is no limit on the packet size that
344			can be received.
345
346			=head3 First Greeting Line
347	root	1.12
348	root	1.16	Example:
349
350			aemp;0;fec.4a7720fc;127.0.0.1:1235,[::1]:1235;hmac_md6_64_256;json,storable;provider=AE-0.0
351
352			The first line contains strings separated (not ended) by C<;>
353			characters. The first even ixtrings are fixed by the protocol, the
354			remaining strings are C<KEY=VALUE> pairs. None of them may contain C<;>
355			characters themselves.
356
357	root	1.12	The fixed strings are:
358	root	1.7
359			=over 4
360
361	root	1.18	=item protocol identification
362	root	1.7
363			The constant C<aemp> to identify the protocol.
364
365			=item protocol version
366
367	root	1.12	The protocol version supported by this end, currently C<0>. If the
368			versions don't match then no communication is possible. Minor extensions
369	root	1.18	are supposed to be handled through additional key-value pairs.
370	root	1.7
371			=item a token uniquely identifying the current node instance
372
373			This is a string that must change between restarts. It usually contains
374			things like the current time, the (OS) process id or similar values, but
375			no meaning of the contents are assumed.
376
377			=item the node endpoint descriptors
378
379			for public nodes, this is a comma-separated list of protocol endpoints,
380			i.e., the noderef. For slave nodes, this is a unique identifier.
381
382			=item the acceptable authentication methods
383
384			A comma-separated list of authentication methods supported by the
385			node. Note that AnyEvent::MP supports a C<hex_secret> authentication
386			method that accepts a cleartext password (hex-encoded), but will not use
387			this auth method itself.
388
389			The receiving side should choose the first auth method it supports.
390
391			=item the acceptable framing formats
392
393			A comma-separated list of packet encoding/framign formats understood. The
394			receiving side should choose the first framing format it supports for
395			sending packets (which might be different from the format it has to accept).
396
397	root	1.10	=back
398	root	1.8
399			The remaining arguments are C<KEY=VALUE> pairs. The following key-value
400			pairs are known at this time:
401
402			=over 4
403
404			=item provider=<module-version>
405
406			The software provider for this implementation. For AnyEvent::MP, this is
407			C<AE-0.0> or whatever version it currently is at.
408
409			=item peeraddr=<host>:<port>
410
411			The peer address (socket address of the other side) as seen locally, in the same format
412			as noderef endpoints.
413
414			=item tls=<major>.<minor>
415
416			Indicates that the other side supports TLS (version should be 1.0) and
417			wishes to do a TLS handshake.
418
419			=back
420
421	root	1.15	=head3 Second Greeting Line
422
423	root	1.8	After this greeting line there will be a second line containing a
424			cryptographic nonce, i.e. random data of high quality. To keep the
425			protocol text-only, these are usually 32 base64-encoded octets, but
426			it could be anything that doesn't contain any ASCII CR or ASCII LF
427			characters.
428
429	root	1.14	I<< The two nonces B<must> be different, and an aemp implementation
430			B<must> check and fail when they are identical >>.
431
432	root	1.16	Example of a nonce line:
433	root	1.8
434	root	1.12	p/I122ql7kJR8lumW3lXlXCeBnyDAvz8NQo3x5IFowE4
435	root	1.8
436			=head2 TLS handshake
437
438	root	1.14	I<< If, after the handshake, both sides indicate interest in TLS, then the
439	root	1.20	connection B<must> use TLS, or fail. >>
440	root	1.8
441			Both sides compare their nonces, and the side who sent the lower nonce
442			value ("string" comparison on the raw octet values) becomes the client,
443			and the one with the higher nonce the server.
444
445			=head2 AUTHENTICATION PHASE
446
447			After the greeting is received (and the optional TLS handshake),
448			the authentication phase begins, which consists of sending a single
449			C<;>-separated line with three fixed strings and any number of
450			C<KEY=VALUE> pairs.
451
452			The three fixed strings are:
453
454			=over 4
455
456			=item the authentication method chosen
457
458			This must be one of the methods offered by the other side in the greeting.
459
460	root	1.13	The currently supported authentication methods are:
461
462			=over 4
463
464			=item cleartext
465
466			This is simply the shared secret, lowercase-hex-encoded. This method is of
467			course very insecure, unless TLS is used, which is why this module will
468			accept, but not generate, cleartext auth replies.
469
470			=item hmac_md6_64_256
471
472			This method uses an MD6 HMAC with 64 bit blocksize and 256 bit hash. First, the shared secret
473			is hashed with MD6:
474
475			key = MD6 (secret)
476
477			This secret is then used to generate the "local auth reply", by taking
478			the two local greeting lines and the two remote greeting lines (without
479			line endings), appending \012 to all of them, concatenating them and
480			calculating the MD6 HMAC with the key.
481
482			lauth = HMAC_MD6 key, "lgreeting1\012lgreeting2\012rgreeting1\012rgreeting2\012"
483
484			This authentication token is then lowercase-hex-encoded and sent to the
485			other side.
486
487			Then the remote auth reply is generated using the same method, but local
488			and remote greeting lines swapped:
489
490			rauth = HMAC_MD6 key, "rgreeting1\012rgreeting2\012lgreeting1\012lgreeting2\012"
491
492			This is the token that is expected from the other side.
493
494	root	1.19	=item tls
495
496			This type is only valid iff TLS was enabled and the TLS handshake
497			was successful. It has no authentication data, as the server/client
498			certificate was successfully verified.
499
500			Implementations supporting TLS I<must> accept this authentication type.
501
502	root	1.13	=back
503
504	root	1.8	=item the authentication data
505
506	root	1.13	The authentication data itself, usually base64 or hex-encoded data, see
507			above.
508	root	1.8
509			=item the framing protocol chosen
510
511			This must be one of the framing protocols offered by the other side in the
512			greeting. Each side must accept the choice of the other side.
513
514			=back
515
516	root	1.16	Example of an authentication reply:
517	root	1.9
518	root	1.13	hmac_md6_64_256;363d5175df38bd9eaddd3f6ca18aa1c0c4aa22f0da245ac638d048398c26b8d3;json
519	root	1.9
520	root	1.8	=head2 DATA PHASE
521
522			After this, packets get exchanged using the chosen framing protocol. It is
523			quite possible that both sides use a different framing protocol.
524
525	root	1.16	=head2 FULL EXAMPLE
526
527	root	1.17	This is an actual protocol dump of a handshake, followed by a single data
528	root	1.16	packet. The greater than/less than lines indicate the direction of the
529			transfer only.
530
531			> aemp;0;nndKd+gn;10.0.0.1:4040;hmac_md6_64_256,cleartext;json,storable;provider=AE-0.0;peeraddr=127.0.0.1:1235
532			> sRG8bbc4TDbkpvH8FTP4HBs87OhepH6VuApoZqXXskuG
533			< aemp;0;nmpKd+gh;127.0.0.1:1235,[::1]:1235;hmac_md6_64_256,cleartext;json,storable;provider=AE-0.0;peeraddr=127.0.0.1:58760
534			< dCEUcL/LJVSTJcx8byEsOzrwhzJYOq+L3YcopA5T6EAo
535			> hmac_md6_64_256;9513d4b258975accfcb2ab7532b83690e9c119a502c612203332a591c7237788;json
536			< hmac_md6_64_256;0298d6ba2240faabb2b2e881cf86b97d70a113ca74a87dc006f9f1e9d3010f90;json
537	root	1.18	> ["","lookup","pinger","10.0.0.1:4040#nndKd+gn.a","resolved"]
538	root	1.16
539	root	1.1	=head1 SEE ALSO
540
541			L<AnyEvent>.
542
543			=head1 AUTHOR
544
545			Marc Lehmann <schmorp@schmorp.de>
546			http://home.schmorp.de/
547
548			=cut
549
550			1
551