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irkerd 28.44 KiB
#!/usr/bin/env python
from __future__ import with_statement
"""
irkerd - a simple IRC multiplexer daemon
Listens for JSON objects of the form {'to':<irc-url>, 'privmsg':<text>}
and relays messages to IRC channels. Each request must be followed by
a newline.
The <text> must be a string. The value of the 'to' attribute can be a
string containing an IRC URL (e.g. 'irc://chat.freenet.net/botwar') or
a list of such strings; in the latter case the message is broadcast to
all listed channels. Note that the channel portion of the URL need
*not* have a leading '#' unless the channel name itself does.
Options: -d sets the debug-message level (probably only of interest to
developers). -l sets a logfile to capture message traffic from
channels. -n sets the nick and -p the nickserv password. The -V
option prints the program version and exits.
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 or 2.5 with the simplejson library installed, and
the irc client library at version >= 3.4 which requires 2.6: see
http://pypi.python.org/pypi/irc/
"""
# These things might need tuning
HOST = "localhost"
PORT = 6659
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 = 1.0 # 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
version = "1.20"
import sys, getopt, urlparse, time, random, socket, signal, re
import threading, Queue, SocketServer
import irc.client, logging
try:
import simplejson as json # Faster, also makes us Python-2.4-compatible
except ImportError:
import json
# Sketch of implementation:
#
# One Irker object manages multiple IRC sessions. It holds a map of
# Dispatcher objects, one per (server, port) combination, which are
# responsible for routing messages to one of any number of Connection
# objects that do the actual socket conversations. The reason for the
# Dispatcher layer is that IRC daemons limit the number of channels a
# client (that is, from the daemon's point of view, a socket) can be
# joined to, so each session to a server needs a flock of Connection
# instances each with its own socket.
#
# Connections are timed out and removed when either they haven't seen a
# PING for a while (indicating that the server may be stalled or down)
# or there has been no message traffic to them for a while, or
# 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. 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, 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):
self.irker = irkerd
self.servername = servername
self.port = port
self.nick_trial = None
self.connection = None
self.status = None
self.last_xmit = time.time()
self.last_ping = time.time()
self.channels_joined = {}
self.channel_limits = {}
# The consumer thread
self.queue = Queue.Queue()
self.thread = None
def nickname(self, n=None):
"Return a name for the nth server connection."
if n is None:
n = self.nick_trial
if fallback:
return (namestyle % n)
else:
return namestyle
def handle_ping(self):
"Register the fact that the server has pinged this connection."
self.last_ping = time.time()
def handle_welcome(self):
"The server says we're OK, with a non-conflicting nick."
self.status = "ready"
self.irker.debug(1, "nick %s accepted" % self.nickname())
if password:
self.connection.privmsg("nickserv", "identify %s" % password)
def handle_badnick(self):
"The server says our nick is ill-formed or has a conflict."
self.irker.debug(1, "nick %s rejected" % self.nickname())
if fallback:
# Randomness prevents a malicious user or bot from
# anticipating 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())
# Otherwise fall through, it might be possible to
# recover manually.
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"
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()
if channel != outof:
qcopy.append((channel, message))
for (channel, message) in qcopy:
self.queue.put((channel, message))
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."
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.irc.mutex:
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.irc.mutex:
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")
if hasattr(self.connection, "buffer"):
self.connection.buffer.errors = 'replace'
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":
(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))
# An empty message might be used as a keepalive or
# to join a channel for logging, so suppress the
# privmsg send unless there is actual traffic.
if message:
for segment in message.split("\n"):
# Truncate the message if it's too long,
# but we're working with characters here,
# not bytes, so we could be off.
# 500 = 512 - CRLF - 'PRIVMSG ' - ' :'
maxlength = 500 - len(channel)
if len(segment) > maxlength:
segment = segment[:maxlength]
try:
self.connection.privmsg(channel, segment)
except ValueError as err:
self.irker.debug(1, "irclib rejected a message to %s on %s because: %s" % (channel, self.servername, str(err)))
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))
# Maybe this should have its own status?
self.status = "expired"
# 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
finally:
try:
# Make sure we don't leave any zombies behind
self.connection.close()
except:
# Irclib has a habit of throwing fresh exceptions here. Ignore that
pass
def live(self):
"Should this connection not be scavenged?"
return self.status != "expired"
def joined_to(self, channel):
"Is this connection joined to the specified channel?"
return channel in self.channels_joined
def accepting(self, channel):
"Can this connection accept a join of this channel?"
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)
else:
return len(self.channels_joined) < CHANNEL_MAX
class Target():
"Represent a transmission target."
def __init__(self, url):
# Pre-2.6 Pythons don't recognize irc: as a valid URL prefix.
url = url.replace("irc://", "http://")
parsed = urlparse.urlparse(url)
irchost, _, ircport = parsed.netloc.partition(':')
if not ircport:
ircport = 6667
self.servername = irchost
# 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()
# This deals with a tweak in recent versions of urlparse.
if parsed.fragment:
self.channel += "#" + parsed.fragment
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):
"Both components must be present for a valid target."
return self.servername and self.channel
def server(self):
"Return a hashable tuple representing the destination server."
return (self.servername, self.port)
class Dispatcher:
"Manage connections to a particular server-port combination."
def __init__(self, irkerd, servername, port):
self.irker = irkerd
self.servername = servername
self.port = port
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 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."
def __init__(self, debuglevel=0):
self.debuglevel = debuglevel
self.irc = irc.client.IRC()
self.irc.add_global_handler("ping", self._handle_ping)
self.irc.add_global_handler("welcome", self._handle_welcome)
self.irc.add_global_handler("erroneusnickname", self._handle_badnick)
self.irc.add_global_handler("nicknameinuse", self._handle_badnick)
self.irc.add_global_handler("nickcollision", self._handle_badnick)
self.irc.add_global_handler("unavailresource", self._handle_badnick)
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)
self.irc.add_global_handler("all_raw_messages", self._handle_all_raw_messages)
thread = threading.Thread(target=self.irc.process_forever)
thread.setDaemon(True)
self.irc._thread = thread
thread.start()
self.servers = {}
def logerr(self, errmsg):
"Log a processing error."
sys.stderr.write("irkerd: " + errmsg + "\n")
def debug(self, level, errmsg):
"Debugging information."
if self.debuglevel >= level:
sys.stderr.write("irkerd: %s\n" % errmsg)
def _handle_ping(self, connection, _event):
"PING arrived, bump the last-received time for the connection."
if connection.context:
connection.context.handle_ping()
def _handle_welcome(self, connection, _event):
"Welcome arrived, nick accepted for this connection."
if connection.context:
connection.context.handle_welcome()
def _handle_badnick(self, connection, _event):
"Nick not accepted for this connection."
if connection.context:
connection.context.handle_badnick()
def _handle_features(self, connection, event):
"Determine if and how we can set deaf mode."
if connection.context:
cxt = connection.context
arguments = event.arguments
# irclib 5.0 compatibility, because the maintainer is a fool
if callable(arguments):
arguments = arguments()
for lump in arguments:
if lump.startswith("DEAF="):
if not logfile:
connection.mode(cxt.nickname(), "+"+lump[5:])
elif lump.startswith("MAXCHANNELS="):
m = int(lump[12:])
for pref in "#&+":
cxt.channel_limits[pref] = m
self.debug(1, "%s maxchannels is %d"
% (connection.server, m))
elif lump.startswith("CHANLIMIT=#:"):
limits = lump[10:].split(",")
try:
for token in limits:
(prefixes, limit) = token.split(":")
limit = int(limit)
for c in prefixes:
cxt.channel_limits[c] = limit
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 %s disconnected" % connection.server)
connection.close()
if connection.context:
connection.context.handle_disconnect()
def _handle_kick(self, connection, event):
"Server hung up the connection."
target = event.target
# irclib 5.0 compatibility, because the maintainer continues
# to be a fool.
if callable(target):
target = target()
self.debug(1, "irker has been kicked from %s on %s" % (target, connection.server))
if connection.context:
connection.context.handle_kick(target)
def _handle_all_raw_messages(self, _connection, event):
"Log all messages when in watcher mode."
if logfile:
with open(logfile, "a") as logfp:
logfp.write("%03f|%s|%s\n" % \
(time.time(), event.source, event.arguments[0]))
def handle(self, line):
"Perform a JSON relay request."
try:
request = json.loads(line.strip())
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 request - 'to' or 'privmsg' missing: %r" % request)
else:
channels = request['to']
message = request['privmsg']
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 not isinstance(channels, list):
channels = [channels]
for url in channels:
if not isinstance(url, basestring):
self.logerr("malformed request - URL has unexpected type: %r" % url)
else:
target = Target(url)
if not target.valid():
return
if target.server() not in self.servers:
self.servers[target.server()] = Dispatcher(self, target.servername, target.port)
self.servers[target.server()].dispatch(target.channel, message)
# GC dispatchers with no active connections
servernames = self.servers.keys()
for servername in servernames:
if not self.servers[servername].live():
del self.servers[servername]
# If we might be pushing a resource limit
# even after garbage collection, remove a
# session. The goal here is to head off
# DoS attacks that aim at exhausting
# thread space or file descriptors. The
# cost is that attempts to DoS this
# service will cause lots of join/leave
# spam as we scavenge old channels after
# connecting to new ones. The particular
# method used for selecting a session to
# be terminated doesn't matter much; we
# choose the one longest idle on the
# assumption that message activity is likely
# to be clumpy.
if len(self.servers) >= CONNECTION_MAX:
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: %r" % line)
except RuntimeError:
self.logerr("wildly malformed JSON blew the parser stack.")
class IrkerTCPHandler(SocketServer.StreamRequestHandler):
def handle(self):
while True:
line = self.rfile.readline()
if not line:
break
irker.handle(line.strip())
class IrkerUDPHandler(SocketServer.BaseRequestHandler):
def handle(self):
data = self.request[0].strip()
#socket = self.request[1]
irker.handle(data)
def usage():
sys.stdout.write("""
Usage:
irkerd [-d debuglevel] [-l logfile] [-n nick] [-p password] [-V] [-h]
Options
-d set debug level
-l set logfile
-n set nick-style
-p set nickserv password
-V return irkerd version
-h print this help dialog
""")
if __name__ == '__main__':
debuglvl = 0
namestyle = "irker%03d"
password = None
logfile = None
try:
(options, arguments) = getopt.getopt(sys.argv[1:], "d:l:n:p:Vh")
except getopt.GetoptError as e:
sys.stderr.write("%s" % e)
usage()
sys.exit(1)
for (opt, val) in options:
if opt == '-d': # Enable debug/progress messages
debuglvl = int(val)
if debuglvl > 1:
logging.basicConfig(level=logging.DEBUG)
elif opt == '-l': # Logfile mode - report traffic read in
logfile = val
elif opt == '-n': # Force the nick
namestyle = val
elif opt == '-p': # Set a nickserv password
password = val
elif opt == '-V': # Emit version and exit
sys.stdout.write("irkerd version %s\n" % version)
sys.exit(0)
elif opt == '-h':
usage()
sys.exit(0)
fallback = re.search("%.*d", namestyle)
irker = Irker(debuglevel=debuglvl)
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