commit a8e37c5a2ecf19e5762318c1f076f17028f66a25 Author: Nate Hardison nate@dn0a20293b.sunet Date: Sat May 14 15:13:22 2011 -0700

Beginnings of bandwidth limiting --- swfcat.as | 90 ++++++++++++++++++++++++++++++++++++++++++++++++------------ 1 files changed, 72 insertions(+), 18 deletions(-)

diff --git a/swfcat.as b/swfcat.as index fa55b51..423f30a 100644 --- a/swfcat.as +++ b/swfcat.as @@ -36,8 +36,8 @@ package

private var fac_addr:Object;

- [Embed(source="badge.png")] - private var BadgeImage:Class; + //[Embed(source="badge.png")] + //private var BadgeImage:Class;

public function puts(s:String):void { @@ -71,8 +71,8 @@ package

if (this.loaderInfo.parameters["debug"]) addChild(output_text); - else - addChild(new BadgeImage()); + //else + // addChild(new BadgeImage());

fac_spec = this.loaderInfo.parameters["facilitator"]; if (fac_spec) { @@ -168,6 +168,7 @@ import flash.events.ProgressEvent; import flash.events.SecurityErrorEvent; import flash.net.Socket; import flash.utils.ByteArray; +import flash.utils.setInterval;

/* An instance of a client-relay connection. */ class ProxyPair @@ -184,6 +185,19 @@ class ProxyPair

// Parent swfcat, for UI updates. private var ui:swfcat; + + // Proxy transfer rate limit in KB/s + private var rate_limit:uint; + + // Default limit is 10KB/s + private const DEFAULT_RATE_LIMIT:uint = 10000; + + private var curr_rate:Number; + private var historical_rate:Number; + private var lifetime:uint; + + // in milliseconds + private const DEFAULT_RATE_TIMEOUT:uint = 1000;

private function log(msg:String):void { @@ -197,11 +211,16 @@ class ProxyPair "," + this.addr_r.host + ":" + this.addr_r.port + ">"; }

- public function ProxyPair(ui:swfcat, addr_c:Object, addr_r:Object) + public function ProxyPair(ui:swfcat, addr_c:Object, addr_r:Object, rate_limit:uint = DEFAULT_RATE_LIMIT) { this.ui = ui; this.addr_c = addr_c; this.addr_r = addr_r; + this.rate_limit = rate_limit; + this.curr_rate = 0.0; + this.historical_rate = 0.0; + this.lifetime = 0; + setInterval(update_transfer_rate, DEFAULT_RATE_TIMEOUT) }

public function connect():void @@ -259,18 +278,53 @@ class ProxyPair private function client_connected(e:Event):void { log("Client: connected."); - - s_r.addEventListener(ProgressEvent.SOCKET_DATA, function (e:ProgressEvent):void { - var bytes:ByteArray = new ByteArray(); - s_r.readBytes(bytes, 0, e.bytesLoaded); - log("Tor: read " + bytes.length + "."); - s_c.writeBytes(bytes); - }); - s_c.addEventListener(ProgressEvent.SOCKET_DATA, function (e:ProgressEvent):void { - var bytes:ByteArray = new ByteArray(); - s_c.readBytes(bytes, 0, e.bytesLoaded); - log("Client: read " + bytes.length + "."); - s_r.writeBytes(bytes); - }); + add_data_listeners(); + } + + private function add_data_listeners():void + { + s_r.addEventListener(ProgressEvent.SOCKET_DATA, transfer_to_client); + s_c.addEventListener(ProgressEvent.SOCKET_DATA, transfer_to_relay); + } + + private function remove_data_listeners():void + { + s_r.removeEventListener(ProgressEvent.SOCKET_DATA, transfer_to_client); + s_c.removeEventListener(ProgressEvent.SOCKET_DATA, transfer_to_relay); + } + + private function transfer_to_client(e:ProgressEvent):void + { + log("Tor: read " + e.bytesLoaded + "."); + transfer_bytes(s_r, s_c, e.bytesLoaded); + } + + private function transfer_to_relay(e:ProgressEvent):void + { + log("Client: read " + e.bytesLoaded + "."); + transfer_bytes(s_c, s_r, e.bytesLoaded); + } + + private function transfer_bytes(src:Socket, dst:Socket, num_bytes:uint):void + { + var bytes:ByteArray = new ByteArray(); + src.readBytes(bytes, 0, num_bytes); + dst.writeBytes(bytes); + curr_rate += num_bytes; + if (rate_limit_exceeded()) remove_data_listeners(); + } + + private function rate_limit_exceeded():Boolean + { + return curr_rate > rate_limit; + } + + private function update_transfer_rate():void + { + lifetime++; + historical_rate = (0.7 * historical_rate + 0.3 * curr_rate) / lifetime; + curr_rate = historical_rate; + log("Historical rate: " + historical_rate); + log("Current rate: " + curr_rate); } }