Implement announces to I2P BitTorrent trackers

Protocol details: https://geti2p.net/en/docs/applications/bittorrent

src/I2P/I2PManager.py

@@ -3,6 +3,9 @@ import logging
 from gevent.coros import RLock
 from gevent.server import StreamServer
 from gevent.pool import Pool
+from httplib import HTTPConnection
+import urllib2
+
 from i2p import socket
 from i2p.datatypes import Destination
 
@@ -11,6 +14,29 @@ from Site import SiteManager
 from Debug import Debug
 
 
+class I2PHTTPConnection(HTTPConnection):
+    def __init__(self, i2p_manager, site_address, *args, **kwargs):
+        HTTPConnection.__init__(self, *args, **kwargs)
+        self.i2p_manager = i2p_manager
+        self.site_address = site_address
+        self._create_connection = self._create_i2p_connection
+
+    def _create_i2p_connection(self, address, timeout=60,
+                               source_address=None):
+        return self.i2p_manager.createSocket(self.site_address, *address)
+
+class I2PHTTPHandler(urllib2.HTTPHandler):
+    def __init__(self, i2p_manager, site_address, *args, **kwargs):
+        urllib2.HTTPHandler.__init__(self, *args, **kwargs)
+        self.i2p_manager = i2p_manager
+        self.site_address = site_address
+
+    def http_open(self, req):
+        return self.do_open(self._createI2PHTTPConnection, req)
+
+    def _createI2PHTTPConnection(self, *args, **kwargs):
+        return I2PHTTPConnection(self.i2p_manager, self.site_address, *args, **kwargs)
+
 class I2PManager:
     def __init__(self, fileserver_handler=None):
         self.dest_conns = {}  # Destination: SAM connection
@@ -140,3 +166,11 @@ class I2PManager:
                              samaddr=(self.sam_ip, self.sam_port))
         sock.connect((dest, int(port)), site_address)
         return sock
+
+    def lookup(self, name):
+        return socket.lookup(name, (self.sam_ip, self.sam_port))
+
+    def urlopen(self, site_address, url, timeout):
+        handler = I2PHTTPHandler(self, site_address)
+        opener = urllib2.build_opener(handler)
+        return opener.open(url, timeout=50)

src/Site/Site.py

@@ -672,6 +672,11 @@ class Site(object):
     # Gather peers from tracker
     # Return: Complete time or False on error
     def announceTracker(self, tracker_protocol, tracker_address, fileserver_port=0, add_types=[], my_peer_id="", mode="start"):
+        is_i2p = ".i2p" in tracker_address
+        i2p_manager = self.connection_server.i2p_manager
+        if is_i2p and not (i2p_manager and i2p_manager.enabled):
+            return False
+
         s = time.time()
         if "ip4" not in add_types:
             fileserver_port = 0
@@ -698,11 +703,17 @@ class Site(object):
                 'uploaded': 0, 'downloaded': 0, 'left': 0, 'compact': 1, 'numwant': 30,
                 'event': 'started'
             }
+            if is_i2p:
+                params['ip'] = i2p_manager.getDest(self.address).base64()
             req = None
             try:
                 url = "http://" + tracker_address + "?" + urllib.urlencode(params)
+                timeout = 60 if is_i2p else 30
                 # Load url
-                with gevent.Timeout(30, False):  # Make sure of timeout
+                with gevent.Timeout(timeout, False):  # Make sure of timeout
+                    if is_i2p:
+                        req = i2p_manager.urlopen(self.address, url, timeout=50)
+                    else:
                         req = urllib2.urlopen(url, timeout=25)
                     response = req.read()
                     req.fp._sock.recv = None  # Hacky avoidance of memory leak for older python versions
@@ -714,13 +725,31 @@ class Site(object):
                 # Decode peers
                 peer_data = bencode.decode(response)["peers"]
                 response = None
-                peer_count = len(peer_data) / 6
                 peers = []
+                if isinstance(peer_data, str):
+                    # Compact response
+                    peer_length = 32 if is_i2p else 6
+                    peer_count = len(peer_data) / peer_length
                     for peer_offset in xrange(peer_count):
-                    off = 6 * peer_offset
-                    peer = peer_data[off:off + 6]
+                        off = peer_length * peer_offset
+                        peer = peer_data[off:off + peer_length]
+                        if is_i2p:
+                            # TODO measure whether non-compact is faster than compact+lookup
+                            try:
+                                dest = i2p_manager.lookup(peer+".b32.i2p")
+                                peers.append({"addr": dest.base64()+".i2p", "port": 6881})
+                            except Exception:
+                                pass
+                        else:
                             addr, port = struct.unpack('!LH', peer)
                             peers.append({"addr": socket.inet_ntoa(struct.pack('!L', addr)), "port": port})
+                else:
+                    # Non-compact response
+                    for peer in peer_data:
+                        if is_i2p:
+                            peers.append({"addr": peer["ip"]+".i2p", "port": peer["port"]})
+                        else:
+                            peers.append({"addr": peer["ip"], "port": peer["port"]})
             except Exception, err:
                 self.log.debug("Http tracker %s error: %s" % (url, err))
                 if req:
@@ -755,6 +784,8 @@ class Site(object):
             trackers = [tracker for tracker in trackers if not tracker.startswith("udp://")]
         if self.connection_server and not self.connection_server.tor_manager.enabled:
             trackers = [tracker for tracker in trackers if ".onion" not in tracker]
+        if self.connection_server and not self.connection_server.i2p_manager.enabled:
+            trackers = [tracker for tracker in trackers if ".i2p" not in tracker]
 
         if mode == "update" or mode == "more":  # Only announce on one tracker, increment the queried tracker id
             self.last_tracker_id += 1
@@ -772,6 +803,8 @@ class Site(object):
                 add_types.append("ip4")
             if self.connection_server.tor_manager.enabled and self.connection_server.tor_manager.start_onions:
                 add_types.append("onion")
+            if self.connection_server.i2p_manager.enabled and self.connection_server.i2p_manager.start_dests:
+                add_types.append("i2p")
         else:
             my_peer_id = ""