Design and code by Eric S. Raymond <esr@thyrsus.com>. See the project
resource page at <http://www.catb.org/~esr/irker/>.
-Requires Python 2.6 and the irc client library at version >= 2.0.2: see
+Requires Python 2.6 or 2.5 with the simplejson library installed, and
+the irc client library at version >= 2.0.2: see
http://pypi.python.org/pypi/irc/
"""
NAMESTYLE = "irker%03d" # IRC nick template - must contain '%d'
XMIT_TTL = (3 * 60 * 60) # Time to live, seconds from last transmit
PING_TTL = (15 * 60) # Time to live, seconds from last PING
+HANDSHAKE_TTL = 60 # Time to live, seconds from nick transmit
+CHANNEL_TTL = (3 * 60 * 60) # Time to live, seconds from last transmit
DISCONNECT_TTL = (24 * 60 * 60) # Time to live, seconds from last connect
UNSEEN_TTL = 60 # Time to live, seconds since first request
CHANNEL_MAX = 18 # Max channels open per socket (default)
-ANTI_FLOOD_DELAY = 0.125 # Anti-flood delay after transmissions, seconds
+ANTI_FLOOD_DELAY = 0.5 # Anti-flood delay after transmissions, seconds
ANTI_BUZZ_DELAY = 0.09 # Anti-buzz delay after queue-empty check
+CONNECTION_MAX = 200 # To avoid hitting a thread limit
# No user-serviceable parts below this line
-# This black magic imports support for green threads (coroutines),
-# then has kinky sex with the import library internals, replacing
-# "threading" with a coroutine-using impostor. Threads then become
-# ultra-light-weight and cooperatively scheduled.
-try:
- import eventlet
- eventlet.monkey_patch()
- green_threads = True
- # With greenlets we don't worry about thread exhaustion, only the
- # file descriptor limit (typically 1024 on modern Unixes). Thus we
- # can handle a lot more concurrent sessions and generate less
- # join/leave spam under heavy load.
- CONNECTION_MAX = 1000
-except ImportError:
- # Threads are more expensive if we have to use OS-level ones
- # rather than greenlets. We need to avoid pushing thread limits
- # as well as fd limits. See security.txt for discussion.
- CONNECTION_MAX = 200
- green_threads = False
+version = "1.10"
-import sys, json, getopt, urlparse, time, random
+import sys, getopt, urlparse, time, random, socket, signal
import threading, Queue, SocketServer
import irc.client, logging
-
-version = "1.3"
+try:
+ import simplejson as json # Faster, also makes us Python-2.4-compatible
+except ImportError:
+ import json
# Sketch of implementation:
#
# even if the queue is nonempty but efforts to connect have failed for
# a long time.
#
-# There are multiple threads. One accepts incoming traffic from all servers.
-# Each Connection also has a consumer thread and a thread-safe message queue.
-# The program main appends messages to queues as JSON requests are received;
-# the consumer threads try to ship them to servers. When a socket write
-# stalls, it only blocks an individual consumer thread; if it stalls long
-# enough, the session will be timed out.
+# There are multiple threads. One accepts incoming traffic from all
+# servers. Each Connection also has a consumer thread and a
+# thread-safe message queue. The program main appends messages to
+# queues as JSON requests are received; the consumer threads try to
+# ship them to servers. When a socket write stalls, it only blocks an
+# individual consumer thread; if it stalls long enough, the session
+# will be timed out. This solves the biggest problem with a
+# single-threaded implementation, which is that you can't count on a
+# single stalled write not hanging all other traffic - you're at the
+# mercy of the length of the buffers in the TCP/IP layer.
#
# Message delivery is thus not reliable in the face of network stalls,
# but this was considered acceptable because IRC (notoriously) has the
# same problem - there is little point in reliable delivery to a relay
# that is down or unreliable.
#
-# This code uses only NICK, JOIN, MODE, and PRIVMSG. It is strictly
+# This code uses only NICK, JOIN, PART, MODE, and PRIVMSG. It is strictly
# compliant to RFC1459, except for the interpretation and use of the
# DEAF and CHANLIMIT and (obsolete) MAXCHANNELS features. CHANLIMIT
# is as described in the Internet RFC draft
# draft-brocklesby-irc-isupport-03 at <http://www.mirc.com/isupport.html>.
+# The ",isnick" feature is as described in
+# <http://ftp.ics.uci.edu/pub/ietf/uri/draft-mirashi-url-irc-01.txt>.
class Connection:
- def __init__(self, irkerd, servername, port, nick_base=1):
+ def __init__(self, irkerd, servername, port):
self.irker = irkerd
self.servername = servername
self.port = port
- self.nick_trial = nick_base
+ self.nick_trial = None
self.connection = None
- self.status = "unseen"
+ self.status = None
self.last_xmit = time.time()
self.last_ping = time.time()
- self.channels_joined = []
+ self.channels_joined = {}
self.channel_limits = {}
# The consumer thread
self.queue = Queue.Queue()
- self.thread = threading.Thread(target=self.dequeue)
- self.thread.start()
+ self.thread = None
def nickname(self, n=None):
"Return a name for the nth server connection."
if n is None:
# Randomness prevents a malicious user or bot from antcipating the
# next trial name in order to block us from completing the handshake.
self.nick_trial += random.randint(1, 3)
+ self.last_xmit = time.time()
self.connection.nick(self.nickname())
def handle_disconnect(self):
"Server disconnected us for flooding or some other reason."
self.connection = None
+ self.status = "disconnected"
def handle_kick(self, outof):
"We've been kicked."
self.status = "handshaking"
- self.channels_joined.remove(outof)
+ try:
+ del self.channels_joined[outof]
+ except KeyError:
+ self.irker.logerr("kicked by %s from %s that's not joined"
+ % (self.servername, outof))
qcopy = []
while not self.queue.empty():
(channel, message) = self.queue.get()
self.status = "ready"
def enqueue(self, channel, message):
"Enque a message for transmission."
+ if self.thread is None or not self.thread.is_alive():
+ self.status = "unseen"
+ self.thread = threading.Thread(target=self.dequeue)
+ self.thread.setDaemon(True)
+ self.thread.start()
self.queue.put((channel, message))
def dequeue(self):
"Try to ship pending messages from the queue."
- while True:
- # We want to be kind to the IRC servers and not hold unused
- # sockets open forever, so they have a time-to-live. The
- # loop is coded this particular way so that we can drop
- # the actual server connection when its time-to-live
- # expires, then reconnect and resume transmission if the
- # queue fills up again.
- if not self.connection:
- self.connection = self.irker.irc.server()
- self.connection.context = self
- self.nick_trial = 1
- self.channels_joined = []
- # This will throw irc.client.ServerConnectionError on failure
- try:
- self.connection.connect(self.servername,
- self.port,
- nickname=self.nickname(),
- username="irker",
- ircname="irker relaying client")
- self.status = "handshaking"
- self.irker.debug(1, "XMIT_TTL bump (%s connection) at %s" % (self.servername, time.asctime()))
- self.last_xmit = time.time()
- except irc.client.ServerConnectionError:
- self.status = "disconnected"
- elif self.status == "handshaking":
- # Don't buzz on the empty-queue test while we're handshaking
- time.sleep(ANTI_BUZZ_DELAY)
- elif self.queue.empty():
- # Queue is empty, at some point we want to time out
- # the connection rather than holding a socket open in
- # the server forever.
- now = time.time()
- if now > self.last_xmit + XMIT_TTL \
- or now > self.last_ping + PING_TTL:
- self.irker.debug(1, "timing out inactive connection to %s at %s" % (self.servername, time.asctime()))
- self.connection.context = None
- self.connection.close()
- self.connection = None
- self.status = "disconnected"
- else:
- # Prevent this thread from hogging the CPU by pausing
- # for just a little bit after the queue-empty check.
- # As long as this is less that the duration of a human
- # reflex arc it is highly unlikely any human will ever
- # notice.
- time.sleep(ANTI_BUZZ_DELAY)
- elif self.status == "disconnected" \
- and time.time() > self.last_xmit + DISCONNECT_TTL:
- # Queue is nonempty, but the IRC server might be down. Letting
- # failed connections retain queue space forever would be a
- # memory leak.
- self.status = "expired"
- break
- elif self.status == "unseen" \
- and time.time() > self.last_xmit + UNSEEN_TTL:
- # Nasty people could attempt a denial-of-service
- # attack by flooding us with requests with invalid
- # servernames. We guard against this by rapidly
- # expiring connections that have a nonempty queue but
- # have never had a successful open.
- self.status = "expired"
- break
- elif self.status == "ready":
- (channel, message) = self.queue.get()
- if channel not in self.channels_joined:
- self.channels_joined.append(channel)
- self.connection.join(channel)
- for segment in message.split("\n"):
- self.connection.privmsg(channel, segment)
- time.sleep(ANTI_FLOOD_DELAY)
- self.last_xmit = time.time()
- self.irker.debug(1, "XMIT_TTL bump (%s transmission) at %s" % (self.servername, time.asctime()))
- self.queue.task_done()
+ try:
+ while True:
+ # We want to be kind to the IRC servers and not hold unused
+ # sockets open forever, so they have a time-to-live. The
+ # loop is coded this particular way so that we can drop
+ # the actual server connection when its time-to-live
+ # expires, then reconnect and resume transmission if the
+ # queue fills up again.
+ if self.queue.empty():
+ # Queue is empty, at some point we want to time out
+ # the connection rather than holding a socket open in
+ # the server forever.
+ now = time.time()
+ xmit_timeout = now > self.last_xmit + XMIT_TTL
+ ping_timeout = now > self.last_ping + PING_TTL
+ if self.status == "disconnected":
+ # If the queue is empty, we can drop this connection.
+ self.status = "expired"
+ break
+ elif xmit_timeout or ping_timeout:
+ self.irker.debug(1, "timing out connection to %s at %s (ping_timeout=%s, xmit_timeout=%s)" % (self.servername, time.asctime(), ping_timeout, xmit_timeout))
+ with self.irker.library_lock:
+ self.connection.context = None
+ self.connection.quit("transmission timeout")
+ self.connection = None
+ self.status = "disconnected"
+ else:
+ # Prevent this thread from hogging the CPU by pausing
+ # for just a little bit after the queue-empty check.
+ # As long as this is less that the duration of a human
+ # reflex arc it is highly unlikely any human will ever
+ # notice.
+ time.sleep(ANTI_BUZZ_DELAY)
+ elif self.status == "disconnected" \
+ and time.time() > self.last_xmit + DISCONNECT_TTL:
+ # Queue is nonempty, but the IRC server might be
+ # down. Letting failed connections retain queue
+ # space forever would be a memory leak.
+ self.status = "expired"
+ break
+ elif not self.connection:
+ # Queue is nonempty but server isn't connected.
+ with self.irker.library_lock:
+ self.connection = self.irker.irc.server()
+ self.connection.context = self
+ # Try to avoid colliding with other instances
+ self.nick_trial = random.randint(1, 990)
+ self.channels_joined = {}
+ try:
+ # This will throw
+ # irc.client.ServerConnectionError on failure
+ self.connection.connect(self.servername,
+ self.port,
+ nickname=self.nickname(),
+ username="irker",
+ ircname="irker relaying client")
+ self.status = "handshaking"
+ self.irker.debug(1, "XMIT_TTL bump (%s connection) at %s" % (self.servername, time.asctime()))
+ self.last_xmit = time.time()
+ self.last_ping = time.time()
+ except irc.client.ServerConnectionError:
+ self.status = "disconnected"
+ elif self.status == "handshaking":
+ if time.time() > self.last_xmit + HANDSHAKE_TTL:
+ self.status = "expired"
+ break
+ else:
+ # Don't buzz on the empty-queue test while we're
+ # handshaking
+ time.sleep(ANTI_BUZZ_DELAY)
+ elif self.status == "unseen" \
+ and time.time() > self.last_xmit + UNSEEN_TTL:
+ # Nasty people could attempt a denial-of-service
+ # attack by flooding us with requests with invalid
+ # servernames. We guard against this by rapidly
+ # expiring connections that have a nonempty queue but
+ # have never had a successful open.
+ self.status = "expired"
+ break
+ elif self.status == "ready":
+ with self.irker.library_lock:
+ (channel, message) = self.queue.get()
+ if channel not in self.channels_joined:
+ self.connection.join(channel)
+ self.irker.debug(1, "joining %s on %s." % (channel, self.servername))
+ for segment in message.split("\n"):
+ self.connection.privmsg(channel, segment)
+ time.sleep(ANTI_FLOOD_DELAY)
+ self.last_xmit = self.channels_joined[channel] = time.time()
+ self.irker.debug(1, "XMIT_TTL bump (%s transmission) at %s" % (self.servername, time.asctime()))
+ self.queue.task_done()
+ except:
+ (exc_type, _exc_value, exc_traceback) = sys.exc_info()
+ self.irker.logerr("exception %s in thread for %s" % \
+ (exc_type, self.servername))
+ # This is so we can see tracebacks for errors inside the thread
+ # when we need to be able to for debugging purposes.
+ if debuglvl > 0:
+ raise exc_type, _exc_value, exc_traceback
def live(self):
"Should this connection not be scavenged?"
return self.status != "expired"
if self.channel_limits:
match_count = 0
for already in self.channels_joined:
+ # This obscure code is because the RFCs allow separate limits
+ # by channel type (indicated by the first character of the name)
+ # a feature that is almost never actually used.
if already[0] == channel[0]:
match_count += 1
return match_count < self.channel_limits.get(channel[0], CHANNEL_MAX)
if not ircport:
ircport = 6667
self.servername = irchost
- self.channel = parsed.path.lstrip('/')
- if self.channel and self.channel[0] not in "#&+":
+ # IRC channel names are case-insensitive. If we don't smash
+ # case here we may run into problems later. There was a bug
+ # observed on irc.rizon.net where an irkerd user specified #Channel,
+ # got kicked, and irkerd crashed because the server returned
+ # "#channel" in the notification that our kick handler saw.
+ self.channel = parsed.path.lstrip('/').lower()
+ isnick = self.channel.endswith(",isnick")
+ if isnick:
+ self.channel = self.channel[:-7]
+ if self.channel and not isnick and self.channel[0] not in "#&+":
self.channel = "#" + self.channel
self.port = int(ircport)
def valid(self):
self.connections = []
def dispatch(self, channel, message):
"Dispatch messages for our server-port combination."
+ # First, check if there is room for another channel
+ # on any of our existing connections.
connections = [x for x in self.connections if x.live()]
eligibles = [x for x in connections if x.joined_to(channel)] \
or [x for x in connections if x.accepting(channel)]
- if not eligibles:
- newconn = Connection(self.irker,
- self.servername,
- self.port,
- len(self.connections)+1)
- self.connections.append(newconn)
- eligibles = [newconn]
- eligibles[0].enqueue(channel, message)
+ if eligibles:
+ eligibles[0].enqueue(channel, message)
+ return
+ # All connections are full up. Look for one old enough to be
+ # scavenged.
+ ancients = []
+ for connection in connections:
+ for (chan, age) in connections.channels_joined.items():
+ if age < time.time() - CHANNEL_TTL:
+ ancients.append((connection, chan, age))
+ if ancients:
+ ancients.sort(key=lambda x: x[2])
+ (found_connection, drop_channel, _drop_age) = ancients[0]
+ found_connection.part(drop_channel, "scavenged by irkerd")
+ del found_connection.channels_joined[drop_channel]
+ #time.sleep(ANTI_FLOOD_DELAY)
+ found_connection.enqueue(channel, message)
+ return
+ # Didn't find any channels with no recent activity
+ newconn = Connection(self.irker,
+ self.servername,
+ self.port)
+ self.connections.append(newconn)
+ newconn.enqueue(channel, message)
def live(self):
"Does this server-port combination have any live connections?"
self.connections = [x for x in self.connections if x.live()]
return len(self.connections) > 0
+ def last_xmit(self):
+ "Return the time of the most recent transmission."
+ return max(x.last_xmit for x in self.connections)
class Irker:
"Persistent IRC multiplexer."
self.irc.add_global_handler("featurelist", self._handle_features)
self.irc.add_global_handler("disconnect", self._handle_disconnect)
self.irc.add_global_handler("kick", self._handle_kick)
- thread = threading.Thread(target=self.irc.process_forever)
+ self.library_lock = threading.Lock()
+ thread = threading.Thread(target=self._process_forever)
+ thread.setDaemon(True)
self.irc._thread = thread
thread.start()
self.servers = {}
"Debugging information."
if self.debuglevel >= level:
sys.stderr.write("irkerd: %s\n" % errmsg)
+ def _process_forever(self):
+ "IRC library process_forever with mutex."
+ self.debug(1, "process_forever()")
+ while True:
+ with self.library_lock:
+ self.irc.process_once(ANTI_BUZZ_DELAY)
def _handle_ping(self, connection, _event):
"PING arrived, bump the last-received time for the connection."
if connection.context:
m = int(lump[12:])
for pref in "#&+":
cxt.channel_limits[pref] = m
- self.debug(1, "%s maxchannels is %d" \
+ self.debug(1, "%s maxchannels is %d"
% (connection.server, m))
elif lump.startswith("CHANLIMIT=#:"):
limits = lump[10:].split(",")
limit = int(limit)
for c in prefixes:
cxt.channel_limits[c] = limit
- self.debug(1, "%s channel limit map is %s" \
+ self.debug(1, "%s channel limit map is %s"
% (connection.server, cxt.channel_limits))
except ValueError:
self.logerr("ill-formed CHANLIMIT property")
def _handle_disconnect(self, connection, _event):
"Server hung up the connection."
- self.debug(1, "server disconnected")
+ self.debug(1, "server %s disconnected" % connection.server)
+ connection.close()
if connection.context:
connection.context.handle_disconnect()
def _handle_kick(self, connection, event):
"Server hung up the connection."
- self.debug(1, "irker has been kicked from %s" % event.target())
+ self.debug(1, "irker has been kicked from %s on %s" % (event.target(), connection.server))
if connection.context:
connection.context.handle_kick(event.target())
def handle(self, line):
"Perform a JSON relay request."
try:
request = json.loads(line.strip())
- if type(request) != type({}):
- self.logerr("request in tot a JSON dictionary: %s" % repr(request))
+ if not isinstance(request, dict):
+ self.logerr("request is not a JSON dictionary: %r" % request)
elif "to" not in request or "privmsg" not in request:
- self.logerr("malformed reqest - 'to' or 'privmsg' missing: %s" % repr(request))
+ self.logerr("malformed request - 'to' or 'privmsg' missing: %r" % request)
else:
channels = request['to']
message = request['privmsg']
- if type(channels) not in (type([]), type(u"")) \
- or type(message) != type(u""):
- self.logerr("malformed request - unexpected types: %s" % repr(request))
+ if not isinstance(channels, (list, basestring)):
+ self.logerr("malformed request - unexpected channel type: %r" % channels)
+ if not isinstance(message, basestring):
+ self.logerr("malformed request - unexpected message type: %r" % message)
else:
- if type(channels) == type(u""):
+ if not isinstance(channels, list):
channels = [channels]
for url in channels:
- if type(url) != type(u""):
- self.logerr("malformed request - unexpected type: %s" % repr(request))
+ if not isinstance(url, basestring):
+ self.logerr("malformed request - URL has unexpected type: %r" % url)
else:
target = Target(url)
if not target.valid():
# choose the one longest idle on the
# assumption that message activity is likely
# to be clumpy.
- oldest = None
if len(self.servers) >= CONNECTION_MAX:
- for (name, server) in self.servers.items():
- if not oldest or server.last_xmit < self.servers[oldest].last_xmit:
- oldest = name
+ oldest = min(self.servers.keys(), key=lambda name: self.servers[name].last_xmit())
del self.servers[oldest]
except ValueError:
- self.logerr("can't recognize JSON on input: %s" % repr(line))
+ self.logerr("can't recognize JSON on input: %r" % line)
except RuntimeError:
self.logerr("wildly malformed JSON blew the parser stack.")
sys.stdout.write("irkerd version %s\n" % version)
sys.exit(0)
irker = Irker(debuglevel=debuglvl)
- tcpserver = SocketServer.TCPServer((HOST, PORT), IrkerTCPHandler)
- udpserver = SocketServer.UDPServer((HOST, PORT), IrkerUDPHandler)
- threading.Thread(target=tcpserver.serve_forever).start()
- threading.Thread(target=udpserver.serve_forever).start()
- # Main thread has to stay alive forever for the cooperative
- # scheduling of the green threads to work.
- if green_threads:
- while True:
- time.sleep(10)
+ irker.debug(1, "irkerd version %s" % version)
+ try:
+ tcpserver = SocketServer.TCPServer((HOST, PORT), IrkerTCPHandler)
+ udpserver = SocketServer.UDPServer((HOST, PORT), IrkerUDPHandler)
+ for server in [tcpserver, udpserver]:
+ server = threading.Thread(target=server.serve_forever)
+ server.setDaemon(True)
+ server.start()
+ try:
+ signal.pause()
+ except KeyboardInterrupt:
+ raise SystemExit(1)
+ except socket.error, e:
+ sys.stderr.write("irkerd: server launch failed: %r\n" % e)
# end