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 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{tls_ctx_disabled} ||= {
         sslv2  => 0,
         sslv3  => 0,
         tlsv1  => 1,
         verify => 1,
         cert_file => "secret.pem",
         ca_file   => "secret.pem",
         verify_require_client_cert => 1,
      };

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

      $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 $secret = $arg{secret};
      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];

            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});
            }
         
            # auth
            require Digest::MD6;
            require Digest::HMAC_MD6;

            my $key   = Digest::MD6::md6 ($secret);
            my $lauth = Digest::HMAC_MD6::hmac_md6_hex ($key, "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012", 64, 256);

            my $rauth =
               $s_auth eq "hmac_md6_64_256" ? Digest::HMAC_MD6::hmac_md6_hex ($key, "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012", 64, 256)
             : $s_auth eq "cleartext"       ? unpack "H*", $secret
             : die;

            $lauth ne $rauth # echo attack?
               or return $self->error ("authentication error");

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

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

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

               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) {
      $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 C<aemp>

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 by addign 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.

=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
   > ["","wkp","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:	1.17
Committed:	Tue Aug 4 14:10:51 2009 UTC (14 years, 10 months ago) by root
Branch:	MAIN
Changes since 1.16:	+1 -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			use AE ();
33			use AnyEvent::Socket ();
34			use AnyEvent::Handle ();
35	root	1.2
36	root	1.1	use base Exporter::;
37
38			our $VERSION = '0.0';
39	root	1.2	our $PROTOCOL_VERSION = 0;
40	root	1.1
41			=item $listener = mp_listener $host, $port, <constructor-args>, $cb->($transport)
42
43			Creates a listener on the given host/port using
44			C<AnyEvent::Socket::tcp_server>.
45
46			See C<new>, below, for constructor arguments.
47
48	root	1.10	Defaults for peerhost, peerport and fh are provided.
49	root	1.1
50			=cut
51
52			sub mp_server($$@) {
53			my $cb = pop;
54			my ($host, $port, @args) = @_;
55
56			AnyEvent::Socket::tcp_server $host, $port, sub {
57			my ($fh, $host, $port) = @_;
58
59			$cb->(new AnyEvent::MP::Transport
60			fh => $fh,
61			peerhost => $host,
62			peerport => $port,
63			@args,
64			);
65			}
66			}
67
68	root	1.2	=item $guard = mp_connect $host, $port, <constructor-args>, $cb->($transport)
69
70			=cut
71
72			sub mp_connect {
73			my $cb = pop;
74			my ($host, $port, @args) = @_;
75
76			AnyEvent::Socket::tcp_connect $host, $port, sub {
77			my ($fh, $nhost, $nport) = @_;
78
79			return $cb->() unless $fh;
80
81			$cb->(new AnyEvent::MP::Transport
82			fh => $fh,
83			peername => $host,
84			peerhost => $nhost,
85			peerport => $nport,
86			@args,
87			);
88			}
89			}
90
91	root	1.1	=item new AnyEvent::MP::Transport
92
93			# immediately starts negotiation
94			my $transport = new AnyEvent::MP::Transport
95	root	1.2	# mandatory
96	root	1.1	fh => $filehandle,
97	root	1.2	local_id => $identifier,
98	root	1.1	on_recv => sub { receive-callback },
99			on_error => sub { error-callback },
100
101			# optional
102			secret => "shared secret",
103			on_eof => sub { clean-close-callback },
104			on_connect => sub { successful-connect-callback },
105	root	1.2	greeting => { key => value },
106	root	1.1
107			# tls support
108			tls_ctx => AnyEvent::TLS,
109			peername => $peername, # for verification
110			;
111
112			=cut
113
114	root	1.7	our @FRAMINGS = qw(json storable); # the framing types we accept and send, in order of preference
115			our @AUTH_SND = qw(hmac_md6_64_256); # auth types we send
116	root	1.13	our @AUTH_RCV = (@AUTH_SND, qw(cleartext)); # auth types we accept
117	root	1.7
118			#AnyEvent::Handle::register_write_type mp_record => sub {
119			#};
120	root	1.4
121	root	1.1	sub new {
122			my ($class, %arg) = @_;
123
124			my $self = bless \%arg, $class;
125
126			$self->{queue} = [];
127
128			{
129			Scalar::Util::weaken (my $self = $self);
130
131	root	1.11	$arg{tls_ctx_disabled} \|\|= {
132			sslv2 => 0,
133			sslv3 => 0,
134			tlsv1 => 1,
135			verify => 1,
136			cert_file => "secret.pem",
137			ca_file => "secret.pem",
138			verify_require_client_cert => 1,
139			};
140	root	1.1
141	root	1.5	$arg{secret} = AnyEvent::MP::Base::default_secret ()
142	root	1.2	unless exists $arg{secret};
143
144	root	1.1	$self->{hdl} = new AnyEvent::Handle
145	root	1.2	fh => delete $arg{fh},
146	root	1.4	autocork => 1,
147			no_delay => 1,
148	root	1.1	on_error => sub {
149			$self->error ($_[2]);
150			},
151			peername => delete $arg{peername},
152			;
153
154	root	1.2	my $secret = $arg{secret};
155			my $greeting_kv = $self->{greeting} \|\|= {};
156	root	1.8	$greeting_kv->{"tls"} = "1.0"
157			if $arg{tls_ctx};
158	root	1.2	$greeting_kv->{provider} = "AE-$VERSION";
159	root	1.7	$greeting_kv->{peeraddr} = AnyEvent::Socket::format_hostport $self->{peerhost}, $self->{peerport};
160	root	1.1
161			# send greeting
162	root	1.12	my $lgreeting1 = "aemp;$PROTOCOL_VERSION"
163	root	1.7	. ";$AnyEvent::MP::Base::UNIQ"
164			. ";$AnyEvent::MP::Base::NODE"
165			. ";" . (join ",", @AUTH_RCV)
166			. ";" . (join ",", @FRAMINGS)
167			. (join "", map ";$_=$greeting_kv->{$_}", keys %$greeting_kv);
168	root	1.12
169	root	1.7	my $lgreeting2 = MIME::Base64::encode_base64 AnyEvent::MP::Base::nonce (33), "";
170	root	1.1
171	root	1.7	$self->{hdl}->push_write ("$lgreeting1\012$lgreeting2\012");
172	root	1.1
173			# expect greeting
174	root	1.12	$self->{hdl}->rbuf_max (4 * 1024);
175	root	1.1	$self->{hdl}->push_read (line => sub {
176	root	1.7	my $rgreeting1 = $_[1];
177	root	1.1
178	root	1.12	my ($aemp, $version, $uniq, $rnode, $auths, $framings, @kv) = split /;/, $rgreeting1;
179	root	1.1
180			if ($aemp ne "aemp") {
181			return $self->error ("unparsable greeting");
182	root	1.12	} elsif ($version != $PROTOCOL_VERSION) {
183			return $self->error ("version mismatch (we: $PROTOCOL_VERSION, they: $version)");
184	root	1.1	}
185
186	root	1.7	my $s_auth;
187			for my $auth_ (split /,/, $auths) {
188			if (grep $auth_ eq $_, @AUTH_SND) {
189			$s_auth = $auth_;
190			last;
191			}
192			}
193
194			defined $s_auth
195			or return $self->error ("$auths: no common auth type supported");
196
197			die unless $s_auth eq "hmac_md6_64_256"; # hardcoded atm.
198
199			my $s_framing;
200			for my $framing_ (split /,/, $framings) {
201			if (grep $framing_ eq $_, @FRAMINGS) {
202			$s_framing = $framing_;
203			last;
204			}
205			}
206
207			defined $s_framing
208			or return $self->error ("$framings: no common framing method supported");
209
210	root	1.2	$self->{remote_uniq} = $uniq;
211			$self->{remote_node} = $rnode;
212	root	1.1
213	root	1.2	$self->{remote_greeting} = {
214			map /^([^=]+)(?:=(.*))?/ ? ($1 => $2) : (),
215			@kv
216	root	1.1	};
217
218	root	1.7	# read nonce
219			$self->{hdl}->push_read (line => sub {
220			my $rgreeting2 = $_[1];
221
222	root	1.10	if ($self->{tls_ctx} and 1 == int $self->{remote_greeting}{tls}) {
223	root	1.8	$self->{tls} = $lgreeting2 lt $rgreeting2 ? "connect" : "accept";
224			$self->{hdl}->starttls ($self->{tls}, $self->{tls_ctx});
225			}
226
227	root	1.7	# auth
228			require Digest::MD6;
229			require Digest::HMAC_MD6;
230	root	1.1
231	root	1.11	my $key = Digest::MD6::md6 ($secret);
232	root	1.13	my $lauth = Digest::HMAC_MD6::hmac_md6_hex ($key, "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012", 64, 256);
233	root	1.1
234	root	1.7	my $rauth =
235	root	1.13	$s_auth eq "hmac_md6_64_256" ? Digest::HMAC_MD6::hmac_md6_hex ($key, "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012", 64, 256)
236			: $s_auth eq "cleartext" ? unpack "H*", $secret
237	root	1.7	: die;
238	root	1.1
239	root	1.7	$lauth ne $rauth # echo attack?
240			or return $self->error ("authentication error");
241	root	1.2
242	root	1.7	$self->{hdl}->push_write ("$s_auth;$lauth;$s_framing\012");
243	root	1.2
244	root	1.12	# reasd the authentication response
245	root	1.7	$self->{hdl}->push_read (line => sub {
246			my ($hdl, $rline) = @_;
247	root	1.2
248	root	1.7	my ($auth_method, $rauth2, $r_framing) = split /;/, $rline;
249	root	1.1
250	root	1.7	if ($rauth2 ne $rauth) {
251			return $self->error ("authentication failure/shared secret mismatch");
252			}
253	root	1.1
254	root	1.7	$self->{s_framing} = $s_framing;
255	root	1.2
256	root	1.7	$hdl->rbuf_max (undef);
257			my $queue = delete $self->{queue}; # we are connected
258	root	1.1
259	root	1.7	$self->connected;
260	root	1.1
261	root	1.12	my $src_node = $self->{node};
262
263	root	1.7	$hdl->push_write ($self->{s_framing} => $_)
264			for @$queue;
265	root	1.1
266	root	1.7	my $rmsg; $rmsg = sub {
267			$_[0]->push_read ($r_framing => $rmsg);
268	root	1.1
269	root	1.12	local $AnyEvent::MP::Base::SRCNODE = $src_node;
270			AnyEvent::MP::Base::_inject (@{ $_[1] });
271	root	1.7	};
272			$hdl->push_read ($r_framing => $rmsg);
273			});
274	root	1.1	});
275			});
276			}
277
278			$self
279			}
280
281			sub error {
282			my ($self, $msg) = @_;
283
284	root	1.4	if ($self->{node} && $self->{node}{transport} == $self) {
285			$self->{node}->clr_transport;
286			}
287	root	1.7	$AnyEvent::MP::Base::WARN->("$self->{peerhost}:$self->{peerport}: $msg");
288	root	1.4	$self->destroy;
289	root	1.1	}
290
291	root	1.2	sub connected {
292			my ($self) = @_;
293
294	root	1.5	my $node = AnyEvent::MP::Base::add_node ($self->{remote_node});
295	root	1.4	Scalar::Util::weaken ($self->{node} = $node);
296			$node->set_transport ($self);
297	root	1.2	}
298
299	root	1.1	sub send {
300	root	1.2	$_[0]{hdl}->push_write ($_[0]{s_framing} => $_[1]);
301	root	1.1	}
302
303			sub destroy {
304			my ($self) = @_;
305
306	root	1.2	$self->{hdl}->destroy
307			if $self->{hdl};
308	root	1.1	}
309
310			sub DESTROY {
311			my ($self) = @_;
312
313			$self->destroy;
314			}
315
316			=back
317
318	root	1.7	=head1 PROTOCOL
319
320			The protocol is relatively simple, and consists of three phases which are
321			symmetrical for both sides: greeting (followed by optionally switching to
322			TLS mode), authentication and packet exchange.
323
324			the protocol is designed to allow both full-text and binary streams.
325
326			The greeting consists of two text lines that are ended by either an ASCII
327			CR LF pair, or a single ASCII LF (recommended).
328
329			=head2 GREETING
330
331	root	1.15	All the lines until after authentication must not exceed 4kb in length,
332			including delimiter. Afterwards there is no limit on the packet size that
333			can be received.
334
335			=head3 First Greeting Line
336	root	1.12
337	root	1.16	Example:
338
339			aemp;0;fec.4a7720fc;127.0.0.1:1235,[::1]:1235;hmac_md6_64_256;json,storable;provider=AE-0.0
340
341			The first line contains strings separated (not ended) by C<;>
342			characters. The first even ixtrings are fixed by the protocol, the
343			remaining strings are C<KEY=VALUE> pairs. None of them may contain C<;>
344			characters themselves.
345
346	root	1.12	The fixed strings are:
347	root	1.7
348			=over 4
349
350			=item C<aemp>
351
352			The constant C<aemp> to identify the protocol.
353
354			=item protocol version
355
356	root	1.12	The protocol version supported by this end, currently C<0>. If the
357			versions don't match then no communication is possible. Minor extensions
358			are supposed to be handled by addign additional key-value pairs.
359	root	1.7
360			=item a token uniquely identifying the current node instance
361
362			This is a string that must change between restarts. It usually contains
363			things like the current time, the (OS) process id or similar values, but
364			no meaning of the contents are assumed.
365
366			=item the node endpoint descriptors
367
368			for public nodes, this is a comma-separated list of protocol endpoints,
369			i.e., the noderef. For slave nodes, this is a unique identifier.
370
371			=item the acceptable authentication methods
372
373			A comma-separated list of authentication methods supported by the
374			node. Note that AnyEvent::MP supports a C<hex_secret> authentication
375			method that accepts a cleartext password (hex-encoded), but will not use
376			this auth method itself.
377
378			The receiving side should choose the first auth method it supports.
379
380			=item the acceptable framing formats
381
382			A comma-separated list of packet encoding/framign formats understood. The
383			receiving side should choose the first framing format it supports for
384			sending packets (which might be different from the format it has to accept).
385
386	root	1.10	=back
387	root	1.8
388			The remaining arguments are C<KEY=VALUE> pairs. The following key-value
389			pairs are known at this time:
390
391			=over 4
392
393			=item provider=<module-version>
394
395			The software provider for this implementation. For AnyEvent::MP, this is
396			C<AE-0.0> or whatever version it currently is at.
397
398			=item peeraddr=<host>:<port>
399
400			The peer address (socket address of the other side) as seen locally, in the same format
401			as noderef endpoints.
402
403			=item tls=<major>.<minor>
404
405			Indicates that the other side supports TLS (version should be 1.0) and
406			wishes to do a TLS handshake.
407
408			=back
409
410	root	1.15	=head3 Second Greeting Line
411
412	root	1.8	After this greeting line there will be a second line containing a
413			cryptographic nonce, i.e. random data of high quality. To keep the
414			protocol text-only, these are usually 32 base64-encoded octets, but
415			it could be anything that doesn't contain any ASCII CR or ASCII LF
416			characters.
417
418	root	1.14	I<< The two nonces B<must> be different, and an aemp implementation
419			B<must> check and fail when they are identical >>.
420
421	root	1.16	Example of a nonce line:
422	root	1.8
423	root	1.12	p/I122ql7kJR8lumW3lXlXCeBnyDAvz8NQo3x5IFowE4
424	root	1.8
425			=head2 TLS handshake
426
427	root	1.14	I<< If, after the handshake, both sides indicate interest in TLS, then the
428			connection B<must> use TLS, or fail.>>
429	root	1.8
430			Both sides compare their nonces, and the side who sent the lower nonce
431			value ("string" comparison on the raw octet values) becomes the client,
432			and the one with the higher nonce the server.
433
434			=head2 AUTHENTICATION PHASE
435
436			After the greeting is received (and the optional TLS handshake),
437			the authentication phase begins, which consists of sending a single
438			C<;>-separated line with three fixed strings and any number of
439			C<KEY=VALUE> pairs.
440
441			The three fixed strings are:
442
443			=over 4
444
445			=item the authentication method chosen
446
447			This must be one of the methods offered by the other side in the greeting.
448
449	root	1.13	The currently supported authentication methods are:
450
451			=over 4
452
453			=item cleartext
454
455			This is simply the shared secret, lowercase-hex-encoded. This method is of
456			course very insecure, unless TLS is used, which is why this module will
457			accept, but not generate, cleartext auth replies.
458
459			=item hmac_md6_64_256
460
461			This method uses an MD6 HMAC with 64 bit blocksize and 256 bit hash. First, the shared secret
462			is hashed with MD6:
463
464			key = MD6 (secret)
465
466			This secret is then used to generate the "local auth reply", by taking
467			the two local greeting lines and the two remote greeting lines (without
468			line endings), appending \012 to all of them, concatenating them and
469			calculating the MD6 HMAC with the key.
470
471			lauth = HMAC_MD6 key, "lgreeting1\012lgreeting2\012rgreeting1\012rgreeting2\012"
472
473			This authentication token is then lowercase-hex-encoded and sent to the
474			other side.
475
476			Then the remote auth reply is generated using the same method, but local
477			and remote greeting lines swapped:
478
479			rauth = HMAC_MD6 key, "rgreeting1\012rgreeting2\012lgreeting1\012lgreeting2\012"
480
481			This is the token that is expected from the other side.
482
483			=back
484
485	root	1.8	=item the authentication data
486
487	root	1.13	The authentication data itself, usually base64 or hex-encoded data, see
488			above.
489	root	1.8
490			=item the framing protocol chosen
491
492			This must be one of the framing protocols offered by the other side in the
493			greeting. Each side must accept the choice of the other side.
494
495			=back
496
497	root	1.16	Example of an authentication reply:
498	root	1.9
499	root	1.13	hmac_md6_64_256;363d5175df38bd9eaddd3f6ca18aa1c0c4aa22f0da245ac638d048398c26b8d3;json
500	root	1.9
501	root	1.8	=head2 DATA PHASE
502
503			After this, packets get exchanged using the chosen framing protocol. It is
504			quite possible that both sides use a different framing protocol.
505
506	root	1.16	=head2 FULL EXAMPLE
507
508	root	1.17	This is an actual protocol dump of a handshake, followed by a single data
509	root	1.16	packet. The greater than/less than lines indicate the direction of the
510			transfer only.
511
512			> 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
513			> sRG8bbc4TDbkpvH8FTP4HBs87OhepH6VuApoZqXXskuG
514			< 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
515			< dCEUcL/LJVSTJcx8byEsOzrwhzJYOq+L3YcopA5T6EAo
516			> hmac_md6_64_256;9513d4b258975accfcb2ab7532b83690e9c119a502c612203332a591c7237788;json
517			< hmac_md6_64_256;0298d6ba2240faabb2b2e881cf86b97d70a113ca74a87dc006f9f1e9d3010f90;json
518			> ["","wkp","pinger","10.0.0.1:4040#nndKd+gn.a","resolved"]
519
520	root	1.1	=head1 SEE ALSO
521
522			L<AnyEvent>.
523
524			=head1 AUTHOR
525
526			Marc Lehmann <schmorp@schmorp.de>
527			http://home.schmorp.de/
528
529			=cut
530
531			1
532