1 files changed, 291 insertions, 0 deletions

diff --git a/sync_daemon.pl b/sync_daemon.pl
new file mode 100644
index 0000000..5f49422
--- /dev/null
+++ b/sync_daemon.pl
@@ -0,0 +1,291 @@
+#!/usr/bin/perl
+
+use strict;
+
+#use Convert::Bencode_XS qw(:all);
+use Convert::Bencode qw(:all);
+use Data::Dumper;
+use LWP::UserAgent;
+use URI::Escape;
+
+# enable verbose output
+my $debug = 0;
+
+# tracker from where we get our sync data
+my @trackers = ('127.0.0.1:8989');
+# tracker to upload merged data
+my @client_tracker = ('127.0.0.1:8989');
+
+# time to wait between syncs
+my $sleeptime = '300';
+
+# SSL cert and key
+my $ssl_cert = 'cert.pem';
+my $ssl_key = 'key.pem';
+
+foreach(@trackers) {
+        print "Syncing from: $_\n";
+}
+foreach(@client_tracker) {
+        print "Syncing to: $_\n";
+}
+
+my $file = shift;
+
+
+# global hash for storing the merged syncs
+my %merged_syncs;
+
+while(1) {
+        %merged_syncs;
+        my @bencoded_sync_data;
+
+        # fetch the sync from every tracker and put it into an array in bencoded form
+        foreach my $tracker (@trackers) {
+                my $bencoded_sync = fetch_sync($tracker);
+#               my $bencoded_sync = fetch_sync_from_file($file);
+                if($bencoded_sync ne 0 && $bencoded_sync =~ /^d4\:sync/) {
+                        push(@bencoded_sync_data,$bencoded_sync);
+                }
+        }
+
+        # bdecode every sync and throw it into the merged-sync
+        foreach my $bencoded_sync (@bencoded_sync_data) {
+                print "Doing merge...\n";
+                merge_sync(bdecode($bencoded_sync));
+                my $num_torrents = keys(%merged_syncs);
+
+                print "number of torrents: $num_torrents\n";
+        }
+
+        # number of max. peers in one changeset
+        my $peer_limit = 500;
+        # max number of changesets per commit
+        my $max_changesets = 10;
+        my $hash_count = 0;
+        my $peer_count = 0;
+        my $changeset;
+        my @escaped_changesets;
+
+        # run until all hashes are put into changesets and commited to the trackers
+        while(keys(%merged_syncs) != 0) {
+
+                foreach my $hash (keys(%merged_syncs)) {
+                        print "Starting new changeset\n" if($peer_count == 0 && $debug);
+                        my $num_peers = keys(%{$merged_syncs{$hash}});
+
+                        print "\t$peer_count peers for $hash_count hashes in changeset\n" if($debug);
+
+                        my $pack_hash = pack('H*',$hash);
+
+                        # as long as the peer_limit is not reached, add new hashes with peers to the changeset hash-table
+                        if($peer_count < $peer_limit) {
+                                print "\t\tAdd $num_peers peers for $hash changeset\n" if($debug);
+                                $peer_count = $peer_count + $num_peers;
+                                foreach my $peer_socket (keys(%{$merged_syncs{$hash}})) {
+
+                                        my $flags = $merged_syncs{$hash}{$peer_socket};
+
+                                        print "\t\t\tAdd $peer_socket $flags\n" if($debug);
+
+                                        my $pack_peer = packme($peer_socket,$flags);
+
+                                        $changeset->{'sync'}->{$pack_hash} = $changeset->{'sync'}->{$pack_hash}.$pack_peer;
+                                }
+                                $hash_count++;
+                                # hash is stored in the changeset, delete it from the hash-table
+                                delete $merged_syncs{$hash};
+                        }
+
+                        # the peer_limit is reached or we are out of torrents, so start preparing a changeset
+                        if($peer_count >= $peer_limit || keys(%merged_syncs) == 0) {
+
+                                print "Commit changeset for $hash_count hashes with $peer_count peers total\n" if($debug);
+
+                                # bencode the changeset
+                                my $enc_changeset = bencode($changeset);
+
+                                # URL-escape the changeset and put into an array of changesets
+                                my $foobar = uri_escape($enc_changeset);
+                                push(@escaped_changesets,$foobar);
+
+                                # the changeset is ready and stored, so delete it from the changeset hash-table
+                                delete $changeset->{'sync'};
+
+                                $hash_count = 0;
+                                $peer_count = 0;
+                                print "\n\n\n" if($debug);
+                        }
+
+                        # if enought changesets are prepared or we are out of torrents for more changesets,
+                        # sync the changesets to the trackers
+                        if($#escaped_changesets == $max_changesets || keys(%merged_syncs) == 0) {
+                                print "\tSync...\n";
+                                sync_to_tracker(\@escaped_changesets);
+                                undef @escaped_changesets;
+                        }
+
+                }
+        }
+
+        print "Sleeping for $sleeptime seconds\n";
+        sleep $sleeptime;
+}
+
+sub connect_tracker {
+        # connect a tracker via HTTPS, returns the body of the response
+        my $url = shift;
+
+        $ENV{HTTPS_DEBUG} = 0;
+        $ENV{HTTPS_CERT_FILE} = $ssl_cert;
+        $ENV{HTTPS_KEY_FILE}  = $ssl_key;
+
+        my $ua = new LWP::UserAgent;
+        my $req = new HTTP::Request('GET', $url);
+        my $res = $ua->request($req);
+
+        my $content = $res->content;
+
+        if($res->is_success()) {
+                return $content;
+        } else {
+                print $res->code."|".$res->status_line."\n";
+                return 0;
+        }
+}
+
+sub sync_to_tracker {
+        # commit changesets to a tracker
+        my @changesets = @{(shift)};
+
+        # prepare the URI with URL-encoded changesets concatenated by a &
+        my $uri = 'sync?';
+        foreach my $set (@changesets) {
+                $uri .= 'changeset='.$set.'&';
+        }
+        my $uri_length = length($uri);
+
+        # commit the collection of changesets to the tracker via HTTPS
+        foreach my $tracker (@client_tracker) {
+                print "\t\tTracker: $tracker (URI: $uri_length)\n";
+                my $url = "https://$tracker/".$uri;
+                connect_tracker($url);
+        }
+}
+
+sub packme {
+        # pack data
+        # returns ipaddr, port and flags in packed format
+        my $peer_socket = shift;
+        my $flags = shift;
+
+        my($a,$b,$c,$d,$port) = split(/[\.,\:]/,$peer_socket);
+        my $pack_peer = pack('C4 n1 b16',$a,$b,$c,$d,$port,$flags);
+
+        return $pack_peer;
+}
+
+sub unpackme {
+        # unpack packed data
+        # returns ipaddr. in quad-form with port (a.b.c.d:port) and flags as bitfield
+        # data is packed as:
+        # - 4 byte ipaddr. (unsigned char value)
+        # - 2 byte port (unsigned short in "network" (big-endian) order)
+        # - 2 byte flags (bit string (ascending bit order inside each byte))
+        my $data = shift;
+
+        my($a, $b, $c, $d, $port, $flags) = unpack('C4 n1 b16',$data);
+        my $peer_socket = "$a\.$b\.$c\.$d\:$port";
+
+        return($peer_socket,$flags);
+}
+
+sub fetch_sync {
+        # fetch sync from a tracker
+        my $tracker = shift;
+        my $url = "https://$tracker/sync";
+
+        print "Fetching from $url\n";
+
+        my $body = connect_tracker($url);
+
+        if($body && $body =~ /^d4\:sync/) {
+                return $body;
+        } else {
+                return 0;
+        }
+}
+
+sub fetch_sync_from_file {
+        # fetch sync from a file
+        my $file = shift;
+        my $body;
+        print "Fetching from file $file\n";
+        open(FILE,"<$file");
+        while(<FILE>) {
+                $body .= $_;
+        }
+        close(FILE);
+        return $body;
+}
+
+sub merge_sync {
+        # This builds a hash table with the torrenthash as keys. The value is a hash table again with the peer-socket as keys
+        # and flags in the value
+        # Example:
+        # 60dd2beb4197f71677c0f5ba92b956f7d04651e5 =>
+        #       192.168.23.23:2323 => 0000000000000000
+        #       23.23.23.23:2342 => 0000000100000000
+        # b220b4d7136e84a88abc090db88bec8604a808f3 =>
+        #       42.23.42.23:55555 => 0000000000000000
+
+        my $hashref = shift;
+ 
+        my $nonuniq_hash_counter = 0;
+        my $nonuniq_peer_counter = 0;
+        my $hash_counter = 0;
+        my $peer_counter = 0;
+
+        foreach my $key (keys(%{$hashref->{'sync'}})) {
+                # start merge for every sha1-hash in the sync
+                my $hash = unpack('H*',$key);
+
+                $hash_counter++;
+                $nonuniq_hash_counter++ if exists $merged_syncs{$hash};
+
+                while(${$hashref->{'sync'}}{$key} ne "")
+                {
+                        # split the value into 8-byte and unpack it for getting peer-socket and flags
+                        my($peer_socket,$flags) = unpackme(substr(${$hashref->{'sync'}}{$key},0,8,''));
+
+                        $peer_counter++;
+                        $nonuniq_peer_counter++ if exists $merged_syncs{$hash}{$peer_socket};
+
+                        # Create a hash table with sha1-hash as key and a hash table as value.
+                        # The hash table in the value has the peer-socket as key and flags as value
+                        # If the entry already exists, the flags are ORed together, if not it is ORed with 0
+                        $merged_syncs{$hash}{$peer_socket} = $flags | $merged_syncs{$hash}{$peer_socket};
+                }
+        }
+        print "$hash_counter hashes $nonuniq_hash_counter non-uniq, $peer_counter peers $nonuniq_peer_counter non-uniq.\n";
+
+}
+
+sub test_decode {
+        my $hashref = shift;
+
+        print "CHANGESET DEBUG OUTPUT\n";
+
+        print Dumper $hashref;
+        foreach my $key (keys(%{$hashref->{'sync'}})) {
+                my $hash = unpack('H*',$key);
+
+                print "Changeset for $hash\n";
+                while(${$hashref->{'sync'}}{$key} ne "")
+                {
+
+                        my($peer_socket,$flags) = unpackme(substr(${$hashref->{'sync'}}{$key},0,8,''));
+                        print "\tSocket: $peer_socket Flags: $flags\n";
+                }
+        }
+}