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1.1 |
=head1 NAME |
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1.13 |
AnyEvent::MP::Transport - actual transport protocol handler |
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1.1 |
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=head1 SYNOPSIS |
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use AnyEvent::MP::Transport; |
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=head1 DESCRIPTION |
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1.43 |
This module implements (and documents) the actual transport protocol for |
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AEMP. |
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1.1 |
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1.7 |
See the "PROTOCOL" section below if you want to write another client for |
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this protocol. |
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1.1 |
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=head1 FUNCTIONS/METHODS |
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=over 4 |
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=cut |
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package AnyEvent::MP::Transport; |
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use common::sense; |
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1.27 |
use Scalar::Util (); |
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use List::Util (); |
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1.1 |
use MIME::Base64 (); |
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use Storable (); |
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1.2 |
use JSON::XS (); |
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1.1 |
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1.19 |
use Digest::MD6 (); |
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use Digest::HMAC_MD6 (); |
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1.1 |
use AE (); |
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use AnyEvent::Socket (); |
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1.27 |
use AnyEvent::Handle 4.92 (); |
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1.2 |
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1.30 |
use AnyEvent::MP::Config (); |
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1.55 |
our $PROTOCOL_VERSION = 1; |
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1.1 |
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1.52 |
our @HOOK_CONNECT; # called at connect/accept time |
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our @HOOK_GREETING; # called at greeting1 time |
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our @HOOK_CONNECTED; # called at data phase |
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our @HOOK_DESTROY; # called at destroy time |
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1.59 |
our %HOOK_PROTOCOL = ( |
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"aemp-dataconn" => sub { |
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require AnyEvent::MP::DataConn; |
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&AnyEvent::MP::DataConn::_inject; |
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}, |
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); |
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1.52 |
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1.39 |
=item $listener = mp_listener $host, $port, <constructor-args> |
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1.1 |
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Creates a listener on the given host/port using |
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C<AnyEvent::Socket::tcp_server>. |
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See C<new>, below, for constructor arguments. |
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1.10 |
Defaults for peerhost, peerport and fh are provided. |
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1.1 |
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=cut |
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1.46 |
sub mp_server($$;%) { |
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my ($host, $port, %arg) = @_; |
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1.1 |
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AnyEvent::Socket::tcp_server $host, $port, sub { |
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my ($fh, $host, $port) = @_; |
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1.39 |
my $tp = new AnyEvent::MP::Transport |
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1.1 |
fh => $fh, |
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peerhost => $host, |
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peerport => $port, |
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1.46 |
%arg, |
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1.39 |
; |
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$tp->{keepalive} = $tp; |
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1.46 |
}, delete $arg{prepare} |
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1.1 |
} |
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1.2 |
=item $guard = mp_connect $host, $port, <constructor-args>, $cb->($transport) |
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=cut |
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sub mp_connect { |
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1.31 |
my $release = pop; |
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1.2 |
my ($host, $port, @args) = @_; |
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1.51 |
new AnyEvent::MP::Transport |
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connect => [$host, $port], |
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1.52 |
peerhost => $host, |
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peerport => $port, |
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1.51 |
release => $release, |
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@args, |
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; |
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1.2 |
} |
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1.1 |
=item new AnyEvent::MP::Transport |
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# immediately starts negotiation |
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my $transport = new AnyEvent::MP::Transport |
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1.2 |
# mandatory |
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1.1 |
fh => $filehandle, |
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1.2 |
local_id => $identifier, |
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1.1 |
on_recv => sub { receive-callback }, |
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on_error => sub { error-callback }, |
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# optional |
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on_eof => sub { clean-close-callback }, |
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on_connect => sub { successful-connect-callback }, |
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1.2 |
greeting => { key => value }, |
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1.1 |
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# tls support |
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tls_ctx => AnyEvent::TLS, |
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peername => $peername, # for verification |
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; |
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=cut |
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sub new { |
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my ($class, %arg) = @_; |
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my $self = bless \%arg, $class; |
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{ |
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Scalar::Util::weaken (my $self = $self); |
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1.50 |
my $config = $AnyEvent::MP::Kernel::CONFIG; |
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1.30 |
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1.50 |
my $timeout = $config->{monitor_timeout}; |
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1.64 |
my $lframing = $config->{framing_format}; |
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1.50 |
my $auth_snd = $config->{auth_offer}; |
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my $auth_rcv = $config->{auth_accept}; |
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1.31 |
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1.42 |
$self->{secret} = $config->{secret} |
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unless exists $self->{secret}; |
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1.2 |
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1.42 |
my $secret = $self->{secret}; |
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1.19 |
|
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1.30 |
if (exists $config->{cert}) { |
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1.42 |
$self->{tls_ctx} = { |
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1.19 |
sslv2 => 0, |
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sslv3 => 0, |
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tlsv1 => 1, |
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verify => 1, |
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1.30 |
cert => $config->{cert}, |
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ca_cert => $config->{cert}, |
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1.19 |
verify_require_client_cert => 1, |
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}; |
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} |
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1.1 |
$self->{hdl} = new AnyEvent::Handle |
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1.52 |
+($self->{fh} ? (fh => $self->{fh}) : (connect => $self->{connect})), |
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1.63 |
autocork => $config->{autocork}, |
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no_delay => exists $config->{nodelay} ? $config->{nodelay} : 1, |
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1.48 |
keepalive => 1, |
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on_error => sub { |
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1.1 |
$self->error ($_[2]); |
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}, |
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1.49 |
rtimeout => $timeout, |
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1.1 |
; |
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1.52 |
my $greeting_kv = $self->{local_greeting} ||= {}; |
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1.24 |
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1.42 |
$greeting_kv->{tls} = "1.0" if $self->{tls_ctx}; |
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1.62 |
$greeting_kv->{provider} = "AE-$AnyEvent::MP::VERSION"; # MP.pm might not be loaded, so best effort :( |
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1.7 |
$greeting_kv->{peeraddr} = AnyEvent::Socket::format_hostport $self->{peerhost}, $self->{peerport}; |
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1.23 |
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1.58 |
my $protocol = $self->{protocol} || "aemp"; |
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1.52 |
# can modify greeting_kv |
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1.58 |
$_->($self) for $protocol eq "aemp" ? @HOOK_CONNECT : (); |
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1.52 |
|
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1.1 |
# send greeting |
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1.58 |
my $lgreeting1 = "$protocol;$PROTOCOL_VERSION" |
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1.52 |
. ";$AnyEvent::MP::Kernel::NODE" |
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1.50 |
. ";" . (join ",", @$auth_rcv) |
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. ";" . (join ",", @$lframing) |
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1.7 |
. (join "", map ";$_=$greeting_kv->{$_}", keys %$greeting_kv); |
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1.12 |
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1.31 |
my $lgreeting2 = MIME::Base64::encode_base64 AnyEvent::MP::Kernel::nonce (66), ""; |
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1.1 |
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1.7 |
$self->{hdl}->push_write ("$lgreeting1\012$lgreeting2\012"); |
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1.1 |
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# expect greeting |
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1.12 |
$self->{hdl}->rbuf_max (4 * 1024); |
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1.1 |
$self->{hdl}->push_read (line => sub { |
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1.7 |
my $rgreeting1 = $_[1]; |
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1.1 |
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1.26 |
my ($aemp, $version, $rnode, $auths, $framings, @kv) = split /;/, $rgreeting1; |
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1.1 |
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1.53 |
$self->{remote_node} = $rnode; |
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$self->{remote_greeting} = { |
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map /^([^=]+)(?:=(.*))?/ ? ($1 => $2) : (), |
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@kv |
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}; |
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1.60 |
# maybe upgrade the protocol |
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if ($protocol eq "aemp" and $aemp =~ /^aemp-\w+$/) { |
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# maybe check for existence of the protocol handler? |
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$self->{protocol} = $protocol = $aemp; |
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} |
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1.58 |
$_->($self) for $protocol eq "aemp" ? @HOOK_GREETING : (); |
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1.54 |
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1.60 |
if ($aemp ne $protocol and $aemp ne "aemp") { |
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1.58 |
return $self->error ("unparsable greeting, expected '$protocol', got '$aemp'"); |
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1.12 |
} elsif ($version != $PROTOCOL_VERSION) { |
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return $self->error ("version mismatch (we: $PROTOCOL_VERSION, they: $version)"); |
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1.60 |
} elsif ($protocol eq "aemp") { |
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if ($rnode eq $AnyEvent::MP::Kernel::NODE) { |
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return $self->error ("I refuse to talk to myself"); |
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} elsif ($AnyEvent::MP::Kernel::NODE{$rnode} && $AnyEvent::MP::Kernel::NODE{$rnode}{transport}) { |
216 |
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return $self->error ("$rnode already connected, not connecting again."); |
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} |
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1.1 |
} |
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1.7 |
# read nonce |
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$self->{hdl}->push_read (line => sub { |
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my $rgreeting2 = $_[1]; |
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1.19 |
"$lgreeting1\012$lgreeting2" ne "$rgreeting1\012$rgreeting2" # echo attack? |
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or return $self->error ("authentication error, echo attack?"); |
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1.41 |
my $tls = $self->{tls_ctx} && 1 == int $self->{remote_greeting}{tls}; |
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my $s_auth; |
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for my $auth_ (split /,/, $auths) { |
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1.50 |
if (grep $auth_ eq $_, @$auth_snd and ($auth_ !~ /^tls_/ or $tls)) { |
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1.41 |
$s_auth = $auth_; |
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last; |
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} |
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} |
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defined $s_auth |
238 |
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or return $self->error ("$auths: no common auth type supported"); |
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my $s_framing; |
241 |
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for my $framing_ (split /,/, $framings) { |
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1.50 |
if (grep $framing_ eq $_, @$lframing) { |
243 |
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1.41 |
$s_framing = $framing_; |
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last; |
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} |
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} |
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defined $s_framing |
249 |
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or return $self->error ("$framings: no common framing method supported"); |
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1.30 |
my $key; |
252 |
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1.19 |
my $lauth; |
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1.41 |
if ($tls) { |
255 |
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1.8 |
$self->{tls} = $lgreeting2 lt $rgreeting2 ? "connect" : "accept"; |
256 |
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$self->{hdl}->starttls ($self->{tls}, $self->{tls_ctx}); |
257 |
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1.66 |
return unless $self->{hdl}; # starttls might destruct us |
258 |
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1.41 |
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$lauth = |
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$s_auth eq "tls_anon" ? "" |
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: $s_auth eq "tls_md6_64_256" ? Digest::MD6::md6_hex "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012" |
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: return $self->error ("$s_auth: fatal, selected unsupported snd auth method"); |
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264 |
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1.30 |
} elsif (length $secret) { |
265 |
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1.41 |
return $self->error ("$s_auth: fatal, selected unsupported snd auth method") |
266 |
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unless $s_auth eq "hmac_md6_64_256"; # hardcoded atm. |
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1.30 |
$key = Digest::MD6::md6 $secret; |
269 |
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1.19 |
# we currently only support hmac_md6_64_256 |
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$lauth = Digest::HMAC_MD6::hmac_md6_hex $key, "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012", 64, 256; |
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1.41 |
|
272 |
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1.30 |
} else { |
273 |
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return $self->error ("unable to handshake TLS and no shared secret configured"); |
274 |
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1.8 |
} |
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1.2 |
|
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1.7 |
$self->{hdl}->push_write ("$s_auth;$lauth;$s_framing\012"); |
277 |
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1.2 |
|
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1.19 |
# read the authentication response |
279 |
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1.7 |
$self->{hdl}->push_read (line => sub { |
280 |
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my ($hdl, $rline) = @_; |
281 |
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1.2 |
|
282 |
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1.7 |
my ($auth_method, $rauth2, $r_framing) = split /;/, $rline; |
283 |
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1.1 |
|
284 |
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1.19 |
my $rauth = |
285 |
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$auth_method eq "hmac_md6_64_256" ? Digest::HMAC_MD6::hmac_md6_hex $key, "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012", 64, 256 |
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: $auth_method eq "cleartext" ? unpack "H*", $secret |
287 |
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1.41 |
: $auth_method eq "tls_anon" ? ($tls ? "" : "\012\012") # \012\012 never matches |
288 |
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: $auth_method eq "tls_md6_64_256" ? ($tls ? Digest::MD6::md6_hex "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012" : "\012\012") |
289 |
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: return $self->error ("$auth_method: fatal, selected unsupported rcv auth method"); |
290 |
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1.19 |
|
291 |
root |
1.7 |
if ($rauth2 ne $rauth) { |
292 |
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return $self->error ("authentication failure/shared secret mismatch"); |
293 |
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} |
294 |
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1.1 |
|
295 |
root |
1.7 |
$self->{s_framing} = $s_framing; |
296 |
root |
1.2 |
|
297 |
root |
1.7 |
$hdl->rbuf_max (undef); |
298 |
root |
1.1 |
|
299 |
root |
1.49 |
# we rely on TCP retransmit timeouts and keepalives |
300 |
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$self->{hdl}->rtimeout (undef); |
301 |
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302 |
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$self->{remote_greeting}{untrusted} = 1 |
303 |
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if $auth_method eq "tls_anon"; |
304 |
root |
1.24 |
|
305 |
root |
1.64 |
if ($protocol eq "aemp" and $self->{hdl}) { |
306 |
root |
1.59 |
# listener-less node need to continuously probe |
307 |
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unless (@$AnyEvent::MP::Kernel::LISTENER) { |
308 |
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$self->{hdl}->wtimeout ($timeout); |
309 |
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$self->{hdl}->on_wtimeout (sub { $self->send ([]) }); |
310 |
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} |
311 |
root |
1.58 |
|
312 |
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# receive handling |
313 |
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my $src_node = $self->{node}; |
314 |
root |
1.65 |
Scalar::Util::weaken $src_node; |
315 |
root |
1.45 |
|
316 |
root |
1.68 |
# optimisation |
317 |
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my $push_write = $hdl->can ("push_write"); |
318 |
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my $push_read = $hdl->can ("push_read"); |
319 |
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320 |
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if ($r_framing eq "json") { |
321 |
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my $coder = JSON::XS->new->utf8; |
322 |
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323 |
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$self->{send} = sub { |
324 |
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$push_write->($hdl, JSON::XS::encode_json $_[0]); |
325 |
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}; |
326 |
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327 |
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$hdl->on_read (sub { |
328 |
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local $AnyEvent::MP::Kernel::SRCNODE = $src_node; |
329 |
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330 |
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AnyEvent::MP::Kernel::_inject (@$_) |
331 |
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for $coder->incr_parse (delete $_[0]{rbuf}); |
332 |
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333 |
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() |
334 |
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}); |
335 |
root |
1.65 |
} else { |
336 |
root |
1.68 |
$self->{send} = sub { |
337 |
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$push_write->($hdl, $s_framing => $_[0]); |
338 |
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}; |
339 |
root |
1.67 |
|
340 |
root |
1.65 |
my $rmsg; $rmsg = $self->{rmsg} = sub { |
341 |
root |
1.67 |
$push_read->($_[0], $r_framing => $rmsg); |
342 |
root |
1.65 |
|
343 |
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local $AnyEvent::MP::Kernel::SRCNODE = $src_node; |
344 |
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AnyEvent::MP::Kernel::_inject (@{ $_[1] }); |
345 |
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}; |
346 |
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eval { |
347 |
root |
1.67 |
$push_read->($_[0], $r_framing => $rmsg); |
348 |
root |
1.65 |
}; |
349 |
|
|
Scalar::Util::weaken $rmsg; |
350 |
|
|
return $self->error ("$r_framing: unusable remote framing") |
351 |
|
|
if $@; |
352 |
|
|
} |
353 |
root |
1.58 |
} |
354 |
root |
1.67 |
|
355 |
|
|
$self->connected; |
356 |
root |
1.7 |
}); |
357 |
root |
1.1 |
}); |
358 |
|
|
}); |
359 |
|
|
} |
360 |
|
|
|
361 |
|
|
$self |
362 |
|
|
} |
363 |
|
|
|
364 |
|
|
sub error { |
365 |
|
|
my ($self, $msg) = @_; |
366 |
|
|
|
367 |
root |
1.39 |
delete $self->{keepalive}; |
368 |
|
|
|
369 |
root |
1.58 |
if ($self->{protocol}) { |
370 |
root |
1.59 |
$HOOK_PROTOCOL{$self->{protocol}}->($self, $msg); |
371 |
root |
1.58 |
} else { |
372 |
|
|
$AnyEvent::MP::Kernel::WARN->(9, "$self->{peerhost}:$self->{peerport} $msg");#d# |
373 |
root |
1.39 |
|
374 |
root |
1.58 |
$self->{node}->transport_error (transport_error => $self->{node}{id}, $msg) |
375 |
|
|
if $self->{node} && $self->{node}{transport} == $self; |
376 |
|
|
} |
377 |
root |
1.31 |
|
378 |
|
|
(delete $self->{release})->() |
379 |
|
|
if exists $self->{release}; |
380 |
|
|
|
381 |
root |
1.37 |
# $AnyEvent::MP::Kernel::WARN->(7, "$self->{peerhost}:$self->{peerport}: $msg"); |
382 |
root |
1.4 |
$self->destroy; |
383 |
root |
1.1 |
} |
384 |
|
|
|
385 |
root |
1.2 |
sub connected { |
386 |
|
|
my ($self) = @_; |
387 |
|
|
|
388 |
root |
1.39 |
delete $self->{keepalive}; |
389 |
|
|
|
390 |
root |
1.58 |
if ($self->{protocol}) { |
391 |
root |
1.59 |
$self->{hdl}->on_error (undef); |
392 |
|
|
$HOOK_PROTOCOL{$self->{protocol}}->($self, undef); |
393 |
root |
1.58 |
} else { |
394 |
|
|
$AnyEvent::MP::Kernel::WARN->(9, "$self->{peerhost}:$self->{peerport} connected as $self->{remote_node}"); |
395 |
|
|
|
396 |
|
|
my $node = AnyEvent::MP::Kernel::add_node ($self->{remote_node}); |
397 |
|
|
Scalar::Util::weaken ($self->{node} = $node); |
398 |
|
|
$node->transport_connect ($self); |
399 |
root |
1.39 |
|
400 |
root |
1.58 |
$_->($self) for @HOOK_CONNECTED; |
401 |
|
|
} |
402 |
root |
1.61 |
|
403 |
|
|
(delete $self->{release})->() |
404 |
|
|
if exists $self->{release}; |
405 |
root |
1.2 |
} |
406 |
|
|
|
407 |
root |
1.1 |
sub destroy { |
408 |
|
|
my ($self) = @_; |
409 |
|
|
|
410 |
root |
1.42 |
(delete $self->{release})->() |
411 |
|
|
if exists $self->{release}; |
412 |
|
|
|
413 |
root |
1.2 |
$self->{hdl}->destroy |
414 |
|
|
if $self->{hdl}; |
415 |
root |
1.52 |
|
416 |
root |
1.59 |
$_->($self) for $self->{protocol} ? () : @HOOK_DESTROY; |
417 |
root |
1.1 |
} |
418 |
|
|
|
419 |
|
|
sub DESTROY { |
420 |
|
|
my ($self) = @_; |
421 |
|
|
|
422 |
|
|
$self->destroy; |
423 |
|
|
} |
424 |
|
|
|
425 |
|
|
=back |
426 |
|
|
|
427 |
root |
1.7 |
=head1 PROTOCOL |
428 |
|
|
|
429 |
root |
1.59 |
The AEMP protocol is comparatively simple, and consists of three phases |
430 |
|
|
which are symmetrical for both sides: greeting (followed by optionally |
431 |
|
|
switching to TLS mode), authentication and packet exchange. |
432 |
root |
1.7 |
|
433 |
root |
1.43 |
The protocol is designed to allow both full-text and binary streams. |
434 |
root |
1.7 |
|
435 |
|
|
The greeting consists of two text lines that are ended by either an ASCII |
436 |
|
|
CR LF pair, or a single ASCII LF (recommended). |
437 |
|
|
|
438 |
|
|
=head2 GREETING |
439 |
|
|
|
440 |
root |
1.15 |
All the lines until after authentication must not exceed 4kb in length, |
441 |
root |
1.43 |
including line delimiter. Afterwards there is no limit on the packet size |
442 |
|
|
that can be received. |
443 |
root |
1.15 |
|
444 |
|
|
=head3 First Greeting Line |
445 |
root |
1.12 |
|
446 |
root |
1.16 |
Example: |
447 |
|
|
|
448 |
root |
1.43 |
aemp;0;rain;tls_md6_64_256,hmac_md6_64_256,tls_anon,cleartext;json,storable;timeout=12;peeraddr=10.0.0.1:48082 |
449 |
root |
1.16 |
|
450 |
|
|
The first line contains strings separated (not ended) by C<;> |
451 |
root |
1.43 |
characters. The first five strings are fixed by the protocol, the |
452 |
root |
1.16 |
remaining strings are C<KEY=VALUE> pairs. None of them may contain C<;> |
453 |
root |
1.43 |
characters themselves (when escaping is needed, use C<%3b> to represent |
454 |
|
|
C<;> and C<%25> to represent C<%>)- |
455 |
root |
1.16 |
|
456 |
root |
1.12 |
The fixed strings are: |
457 |
root |
1.7 |
|
458 |
|
|
=over 4 |
459 |
|
|
|
460 |
root |
1.18 |
=item protocol identification |
461 |
root |
1.7 |
|
462 |
root |
1.43 |
The constant C<aemp> to identify this protocol. |
463 |
root |
1.7 |
|
464 |
|
|
=item protocol version |
465 |
|
|
|
466 |
root |
1.55 |
The protocol version supported by this end, currently C<1>. If the |
467 |
root |
1.12 |
versions don't match then no communication is possible. Minor extensions |
468 |
root |
1.18 |
are supposed to be handled through additional key-value pairs. |
469 |
root |
1.7 |
|
470 |
root |
1.43 |
=item the node ID |
471 |
root |
1.7 |
|
472 |
root |
1.57 |
This is the node ID of the connecting node. |
473 |
root |
1.7 |
|
474 |
|
|
=item the acceptable authentication methods |
475 |
|
|
|
476 |
|
|
A comma-separated list of authentication methods supported by the |
477 |
|
|
node. Note that AnyEvent::MP supports a C<hex_secret> authentication |
478 |
root |
1.43 |
method that accepts a clear-text password (hex-encoded), but will not use |
479 |
|
|
this authentication method itself. |
480 |
root |
1.7 |
|
481 |
root |
1.43 |
The receiving side should choose the first authentication method it |
482 |
|
|
supports. |
483 |
root |
1.7 |
|
484 |
|
|
=item the acceptable framing formats |
485 |
|
|
|
486 |
root |
1.43 |
A comma-separated list of packet encoding/framing formats understood. The |
487 |
root |
1.7 |
receiving side should choose the first framing format it supports for |
488 |
|
|
sending packets (which might be different from the format it has to accept). |
489 |
|
|
|
490 |
root |
1.10 |
=back |
491 |
root |
1.8 |
|
492 |
|
|
The remaining arguments are C<KEY=VALUE> pairs. The following key-value |
493 |
|
|
pairs are known at this time: |
494 |
|
|
|
495 |
|
|
=over 4 |
496 |
|
|
|
497 |
|
|
=item provider=<module-version> |
498 |
|
|
|
499 |
|
|
The software provider for this implementation. For AnyEvent::MP, this is |
500 |
|
|
C<AE-0.0> or whatever version it currently is at. |
501 |
|
|
|
502 |
|
|
=item peeraddr=<host>:<port> |
503 |
|
|
|
504 |
root |
1.39 |
The peer address (socket address of the other side) as seen locally. |
505 |
root |
1.8 |
|
506 |
|
|
=item tls=<major>.<minor> |
507 |
|
|
|
508 |
|
|
Indicates that the other side supports TLS (version should be 1.0) and |
509 |
|
|
wishes to do a TLS handshake. |
510 |
|
|
|
511 |
|
|
=back |
512 |
|
|
|
513 |
root |
1.15 |
=head3 Second Greeting Line |
514 |
|
|
|
515 |
root |
1.8 |
After this greeting line there will be a second line containing a |
516 |
|
|
cryptographic nonce, i.e. random data of high quality. To keep the |
517 |
|
|
protocol text-only, these are usually 32 base64-encoded octets, but |
518 |
|
|
it could be anything that doesn't contain any ASCII CR or ASCII LF |
519 |
|
|
characters. |
520 |
|
|
|
521 |
root |
1.14 |
I<< The two nonces B<must> be different, and an aemp implementation |
522 |
|
|
B<must> check and fail when they are identical >>. |
523 |
|
|
|
524 |
root |
1.43 |
Example of a nonce line (yes, it's random-looking because it is random |
525 |
|
|
data): |
526 |
root |
1.8 |
|
527 |
root |
1.43 |
2XYhdG7/O6epFa4wuP0ujAEx1rXYWRcOypjUYK7eF6yWAQr7gwIN9m/2+mVvBrTPXz5GJDgfGm9d8QRABAbmAP/s |
528 |
root |
1.8 |
|
529 |
|
|
=head2 TLS handshake |
530 |
|
|
|
531 |
root |
1.14 |
I<< If, after the handshake, both sides indicate interest in TLS, then the |
532 |
root |
1.43 |
connection B<must> use TLS, or fail to continue. >> |
533 |
root |
1.8 |
|
534 |
|
|
Both sides compare their nonces, and the side who sent the lower nonce |
535 |
|
|
value ("string" comparison on the raw octet values) becomes the client, |
536 |
|
|
and the one with the higher nonce the server. |
537 |
|
|
|
538 |
|
|
=head2 AUTHENTICATION PHASE |
539 |
|
|
|
540 |
|
|
After the greeting is received (and the optional TLS handshake), |
541 |
|
|
the authentication phase begins, which consists of sending a single |
542 |
|
|
C<;>-separated line with three fixed strings and any number of |
543 |
|
|
C<KEY=VALUE> pairs. |
544 |
|
|
|
545 |
|
|
The three fixed strings are: |
546 |
|
|
|
547 |
|
|
=over 4 |
548 |
|
|
|
549 |
|
|
=item the authentication method chosen |
550 |
|
|
|
551 |
|
|
This must be one of the methods offered by the other side in the greeting. |
552 |
|
|
|
553 |
root |
1.41 |
Note that all methods starting with C<tls_> are only valid I<iff> TLS was |
554 |
|
|
successfully handshaked (and to be secure the implementation must enforce |
555 |
|
|
this). |
556 |
|
|
|
557 |
root |
1.13 |
The currently supported authentication methods are: |
558 |
|
|
|
559 |
|
|
=over 4 |
560 |
|
|
|
561 |
|
|
=item cleartext |
562 |
|
|
|
563 |
|
|
This is simply the shared secret, lowercase-hex-encoded. This method is of |
564 |
root |
1.43 |
course very insecure if TLS is not used (and not completely secure even |
565 |
|
|
if TLS is used), which is why this module will accept, but not generate, |
566 |
|
|
cleartext auth replies. |
567 |
root |
1.13 |
|
568 |
|
|
=item hmac_md6_64_256 |
569 |
|
|
|
570 |
root |
1.43 |
This method uses an MD6 HMAC with 64 bit blocksize and 256 bit hash, and |
571 |
|
|
requires a shared secret. It is the preferred auth method when a shared |
572 |
|
|
secret is available. |
573 |
|
|
|
574 |
|
|
First, the shared secret is hashed with MD6: |
575 |
root |
1.13 |
|
576 |
|
|
key = MD6 (secret) |
577 |
|
|
|
578 |
|
|
This secret is then used to generate the "local auth reply", by taking |
579 |
|
|
the two local greeting lines and the two remote greeting lines (without |
580 |
|
|
line endings), appending \012 to all of them, concatenating them and |
581 |
root |
1.43 |
calculating the MD6 HMAC with the key: |
582 |
root |
1.13 |
|
583 |
|
|
lauth = HMAC_MD6 key, "lgreeting1\012lgreeting2\012rgreeting1\012rgreeting2\012" |
584 |
|
|
|
585 |
|
|
This authentication token is then lowercase-hex-encoded and sent to the |
586 |
|
|
other side. |
587 |
|
|
|
588 |
|
|
Then the remote auth reply is generated using the same method, but local |
589 |
|
|
and remote greeting lines swapped: |
590 |
|
|
|
591 |
|
|
rauth = HMAC_MD6 key, "rgreeting1\012rgreeting2\012lgreeting1\012lgreeting2\012" |
592 |
|
|
|
593 |
|
|
This is the token that is expected from the other side. |
594 |
|
|
|
595 |
root |
1.41 |
=item tls_anon |
596 |
root |
1.19 |
|
597 |
root |
1.43 |
This type is only valid I<iff> TLS was enabled and the TLS handshake |
598 |
root |
1.19 |
was successful. It has no authentication data, as the server/client |
599 |
|
|
certificate was successfully verified. |
600 |
|
|
|
601 |
root |
1.43 |
This authentication type is somewhat insecure, as it allows a |
602 |
|
|
man-in-the-middle attacker to change some of the connection parameters |
603 |
|
|
(such as the framing format), although there is no known attack that |
604 |
|
|
exploits this in a way that is worse than just denying the service. |
605 |
root |
1.41 |
|
606 |
root |
1.43 |
By default, this implementation accepts but never generates this auth |
607 |
|
|
reply. |
608 |
root |
1.41 |
|
609 |
|
|
=item tls_md6_64_256 |
610 |
|
|
|
611 |
root |
1.43 |
This type is only valid I<iff> TLS was enabled and the TLS handshake was |
612 |
|
|
successful. |
613 |
root |
1.41 |
|
614 |
|
|
This authentication type simply calculates: |
615 |
|
|
|
616 |
|
|
lauth = MD6 "rgreeting1\012rgreeting2\012lgreeting1\012lgreeting2\012" |
617 |
|
|
|
618 |
|
|
and lowercase-hex encodes the result and sends it as authentication |
619 |
|
|
data. No shared secret is required (authentication is done by TLS). The |
620 |
root |
1.43 |
checksum exists only to make tinkering with the greeting hard. |
621 |
root |
1.19 |
|
622 |
root |
1.13 |
=back |
623 |
|
|
|
624 |
root |
1.8 |
=item the authentication data |
625 |
|
|
|
626 |
root |
1.13 |
The authentication data itself, usually base64 or hex-encoded data, see |
627 |
|
|
above. |
628 |
root |
1.8 |
|
629 |
|
|
=item the framing protocol chosen |
630 |
|
|
|
631 |
|
|
This must be one of the framing protocols offered by the other side in the |
632 |
root |
1.43 |
greeting. Each side must accept the choice of the other side, and generate |
633 |
|
|
packets in the format it chose itself. |
634 |
root |
1.8 |
|
635 |
|
|
=back |
636 |
|
|
|
637 |
root |
1.16 |
Example of an authentication reply: |
638 |
root |
1.9 |
|
639 |
root |
1.13 |
hmac_md6_64_256;363d5175df38bd9eaddd3f6ca18aa1c0c4aa22f0da245ac638d048398c26b8d3;json |
640 |
root |
1.9 |
|
641 |
root |
1.8 |
=head2 DATA PHASE |
642 |
|
|
|
643 |
|
|
After this, packets get exchanged using the chosen framing protocol. It is |
644 |
|
|
quite possible that both sides use a different framing protocol. |
645 |
|
|
|
646 |
root |
1.16 |
=head2 FULL EXAMPLE |
647 |
|
|
|
648 |
root |
1.17 |
This is an actual protocol dump of a handshake, followed by a single data |
649 |
root |
1.16 |
packet. The greater than/less than lines indicate the direction of the |
650 |
|
|
transfer only. |
651 |
|
|
|
652 |
root |
1.43 |
> aemp;0;anon/57Cs1CggVJjzYaQp13XXg4;tls_md6_64_256,hmac_md6_64_256,tls_anon,cleartext;json,storable;provider=AE-0.8;timeout=12;peeraddr=10.0.0.17:4040 |
653 |
|
|
> yLgdG1ov/02shVkVQer3wzeuywZK+oraTdEQBmIqWHaegxSGDG4g+HqogLQbvdypFOsoDWJ1Sh4ImV4DMhvUBwTK |
654 |
|
|
|
655 |
|
|
< aemp;0;ruth;tls_md6_64_256,hmac_md6_64_256,tls_anon,cleartext;json,storable;provider=AE-0.8;timeout=12;peeraddr=10.0.0.1:37108 |
656 |
|
|
< +xMQXP8ElfNmuvEhsmcp+s2wCJOuQAsPxSg3d2Ewhs6gBnJz+ypVdWJ/wAVrXqlIJfLeVS/CBy4gEGkyWHSuVb1L |
657 |
|
|
|
658 |
|
|
> hmac_md6_64_256;5ad913855742ae5a03a5aeb7eafa4c78629de136bed6acd73eea36c9e98df44a;json |
659 |
|
|
|
660 |
|
|
< hmac_md6_64_256;84cd590976f794914c2ca26dac3a207a57a6798b9171289c114de07cf0c20401;json |
661 |
|
|
< ["","AnyEvent::MP::_spawn","57Cs1CggVJjzYaQp13XXg4.c","AnyEvent::MP::Global::connect",0,"anon/57Cs1CggVJjzYaQp13XXg4"] |
662 |
|
|
... |
663 |
|
|
|
664 |
|
|
The shared secret in use was C<8ugxrtw6H5tKnfPWfaSr4HGhE8MoJXmzTT1BWq7sLutNcD0IbXprQlZjIbl7MBKoeklG3IEfY9GlJthC0pENzk>. |
665 |
root |
1.16 |
|
666 |
root |
1.65 |
=head2 SIMPLE HANDSHAKE FOR NON-PERL NODES |
667 |
|
|
|
668 |
|
|
Implementing the full set of options for handshaking can be a daunting |
669 |
|
|
task. |
670 |
|
|
|
671 |
|
|
If security is not so important (because you only connect locally and |
672 |
|
|
control the host, a common case), and you want to interface with an AEMP |
673 |
|
|
node from another programming language, then you can also implement a |
674 |
|
|
simplified handshake. |
675 |
|
|
|
676 |
|
|
For example, in a simple implementation you could decide to simply not |
677 |
|
|
check the authenticity of the other side and use cleartext authentication |
678 |
|
|
yourself. The the handshake is as simple as sending three lines of text, |
679 |
|
|
reading three lines of text, and then you can exchange JSON-formatted |
680 |
|
|
messages: |
681 |
|
|
|
682 |
|
|
aemp;1;<nodename>;hmac_md6_64_256;json |
683 |
|
|
<nonce> |
684 |
|
|
cleartext;<hexencoded secret>;json |
685 |
|
|
|
686 |
|
|
The nodename should be unique within the network, preferably unique with |
687 |
|
|
every connection, the <nonce> could be empty or some random data, and the |
688 |
|
|
hexencoded secret would be the shared secret, in lowercase hex (e.g. if |
689 |
|
|
the secret is "geheim", the hex-encoded version would be "67656865696d"). |
690 |
|
|
|
691 |
|
|
Note that apart from the low-level handshake and framing protocol, there |
692 |
|
|
is a high-level protocol, e.g. for monitoring, building the mesh or |
693 |
|
|
spawning. All these messages are sent to the node port (the empty string) |
694 |
|
|
and can safely be ignored if you do not need the relevant functionality. |
695 |
|
|
|
696 |
|
|
=head3 USEFUL HINTS |
697 |
|
|
|
698 |
|
|
Since taking part in the global protocol to find port groups is |
699 |
|
|
nontrivial, hardcoding port names should be considered as well, i.e. the |
700 |
|
|
non-Perl node could simply listen to messages for a few well-known ports. |
701 |
|
|
|
702 |
|
|
Alternatively, the non-Perl node could call a (already loaded) function |
703 |
|
|
in the Perl node by sending it a special message: |
704 |
|
|
|
705 |
|
|
["", "Some::Function::name", "myownport", 1, 2, 3] |
706 |
|
|
|
707 |
|
|
This would call the function C<Some::Function::name> with the string |
708 |
|
|
C<myownport> and some additional arguments. |
709 |
|
|
|
710 |
root |
1.49 |
=head2 MONITORING |
711 |
|
|
|
712 |
|
|
Monitoring the connection itself is transport-specific. For TCP, all |
713 |
|
|
connection monitoring is currently left to TCP retransmit time-outs |
714 |
|
|
on a busy link, and TCP keepalive (which should be enabled) for idle |
715 |
|
|
connections. |
716 |
|
|
|
717 |
|
|
This is not sufficient for listener-less nodes, however: they need |
718 |
|
|
to regularly send data (30 seconds, or the monitoring interval, is |
719 |
|
|
recommended), so TCP actively probes. |
720 |
|
|
|
721 |
|
|
Future implementations of AnyEvent::Transport might query the kernel TCP |
722 |
|
|
buffer after a write timeout occurs, and if it is non-empty, shut down the |
723 |
|
|
connections, but this is an area of future research :) |
724 |
|
|
|
725 |
|
|
=head2 NODE PROTOCOL |
726 |
|
|
|
727 |
|
|
The transport simply transfers messages, but to implement a full node, a |
728 |
|
|
special node port must exist that understands a number of requests. |
729 |
|
|
|
730 |
|
|
If you are interested in implementing this, drop us a note so we finish |
731 |
|
|
the documentation. |
732 |
|
|
|
733 |
root |
1.1 |
=head1 SEE ALSO |
734 |
|
|
|
735 |
root |
1.29 |
L<AnyEvent::MP>. |
736 |
root |
1.1 |
|
737 |
|
|
=head1 AUTHOR |
738 |
|
|
|
739 |
|
|
Marc Lehmann <schmorp@schmorp.de> |
740 |
|
|
http://home.schmorp.de/ |
741 |
|
|
|
742 |
|
|
=cut |
743 |
|
|
|
744 |
|
|
1 |
745 |
|
|
|