X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=hippotat.git;a=blobdiff_plain;f=server;h=3abebe96bfb69bdf5921dfa64cf1a8da2f70bbf0;hp=1a9049b845131db9c6148373e6f121853fd60e9a;hb=8e279651cf76bb0e7d532307c0afbfbd7dc4986b;hpb=ec88b1f1080f9adffbe1c4c05c38c01e758f124b diff --git a/server b/server index 1a9049b..3abebe9 100755 --- a/server +++ b/server @@ -1,16 +1,35 @@ -#!/usr/bin/python2 +#!/usr/bin/python3 -from twisted.web.server import Site -from twisted.web.resource import Resource -from twisted.web.server import NOT_DONE_YET +import signal +signal.signal(signal.SIGINT, signal.SIG_DFL) + +import sys +import os + +import twisted +import twisted.internet +import twisted.internet.endpoints from twisted.internet import reactor +from twisted.web.server import NOT_DONE_YET +from twisted.logger import LogLevel -import ConfigParser import ipaddress +from ipaddress import AddressValueError + +#import twisted.web.server import Site +#from twisted.web.resource import Resource + +from optparse import OptionParser +from configparser import ConfigParser +from configparser import NoOptionError + +import collections + +import syslog clients = { } -def ipaddress(input): +def ipaddr(input): try: r = ipaddress.IPv4Address(input) except AddressValueError: @@ -24,58 +43,239 @@ def ipnetwork(input): r = ipaddress.IPv6Network(input) return r -defcfg = u''' -[default] -max_batch_down: 65536 -max_queue_time: 10 -max_request_time: 54 +defcfg = ''' +[DEFAULT] +max_batch_down = 65536 +max_queue_time = 10 +max_request_time = 54 + +[virtual] +mtu = 1500 +# network +# [host] +# [relay] + +[server] +ipif = userv root ipif %(host)s,%(relay)s,%(mtu)s,slip %(network)s +addrs = 127.0.0.1 ::1 +port = 8099 -[global] -max_batch_down: 262144 -max_queue_time: 121 -max_request_time: 121 +[limits] +max_batch_down = 262144 +max_queue_time = 121 +max_request_time = 121 ''' +#---------- error handling ---------- + +def crash(err): + print('CRASH ', err, file=sys.stderr) + try: reactor.stop() + except twisted.internet.error.ReactorNotRunning: pass + +def crash_on_defer(defer): + defer.addErrback(lambda err: crash(err)) + +def crash_on_critical(event): + if event.get('log_level') >= LogLevel.critical: + crash(twisted.logger.formatEvent(event)) + +#---------- "router" ---------- + +def route(packet, saddr, daddr): + print('TRACE ', saddr, daddr, packet) + try: client = clients[daddr] + except KeyError: dclient = None + if dclient is not None: + dclient.queue_outbound(packet) + elif saddr.is_link_local or daddr.is_link_local: + log_discard(packet, saddr, daddr, 'link-local') + elif daddr == host or daddr not in network: + print('TRACE INBOUND ', saddr, daddr, packet) + queue_inbound(packet) + elif daddr == relay: + log_discard(packet, saddr, daddr, 'relay') + else: + log_discard(packet, saddr, daddr, 'no client') + +def log_discard(packet, saddr, daddr, why): + print('DROP ', saddr, daddr, why) +# syslog.syslog(syslog.LOG_DEBUG, +# 'discarded packet %s -> %s (%s)' % (saddr, daddr, why)) + +#---------- ipif (slip subprocess) ---------- + +class IpifProcessProtocol(twisted.internet.protocol.ProcessProtocol): + def __init__(self): + self._buffer = b'' + def connectionMade(self): pass + def outReceived(self, data): + #print('RECV ', repr(data)) + self._buffer += data + packets = slip_decode(self._buffer) + self._buffer = packets.pop() + for packet in packets: + if not len(packet): continue + (saddr, daddr) = packet_addrs(packet) + route(packet, saddr, daddr) + def processEnded(self, status): + status.raiseException() + +def start_ipif(): + global ipif + ipif = IpifProcessProtocol() + reactor.spawnProcess(ipif, + '/bin/sh',['sh','-xc', ipif_command], + childFDs={0:'w', 1:'r', 2:2}) + +def queue_inbound(packet): + ipif.transport.write(slip_delimiter) + ipif.transport.write(slip_encode(packet)) + ipif.transport.write(slip_delimiter) + +#---------- SLIP handling ---------- + +slip_end = b'\300' +slip_esc = b'\333' +slip_esc_end = b'\334' +slip_esc_esc = b'\335' +slip_delimiter = slip_end + +def slip_encode(packet): + return (packet + .replace(slip_esc, slip_esc + slip_esc_esc) + .replace(slip_end, slip_esc + slip_esc_end)) + +def slip_decode(data): + print('DECODE ', repr(data)) + out = [] + for packet in data.split(slip_end): + pdata = b'' + while True: + eix = packet.find(slip_esc) + if eix == -1: + pdata += packet + break + #print('ESC ', repr((pdata, packet, eix))) + pdata += packet[0 : eix] + ck = packet[eix+1] + #print('ESC... %o' % ck) + if ck == slip_esc_esc[0]: pdata += slip_esc + elif ck == slip_esc_end[0]: pdata += slip_end + else: raise ValueError('invalid SLIP escape') + packet = packet[eix+2 : ] + out.append(pdata) + print('DECODED ', repr(out)) + return out + +#---------- packet parsing ---------- + +def packet_addrs(packet): + version = packet[0] >> 4 + if version == 4: + addrlen = 4 + saddroff = 3*4 + factory = ipaddress.IPv4Address + elif version == 6: + addrlen = 16 + saddroff = 2*4 + factory = ipaddress.IPv6Address + else: + raise ValueError('unsupported IP version %d' % version) + saddr = factory(packet[ saddroff : saddroff + addrlen ]) + daddr = factory(packet[ saddroff + addrlen : saddroff + addrlen*2 ]) + return (saddr, daddr) + +#---------- client ---------- + class Client(): - def __init__(ip, cs): + def __init__(self, ip, cs): # instance data members self._ip = ip self._cs = cs self.pw = cfg.get(cs, 'password') - # plus: - # .cfg[] - self.cfg = { } + self._rq = collections.deque() # requests + self._pq = collections.deque() # packets + # plus from config: + # .max_batch_down + # .max_queue_time + # .max_request_time for k in ('max_batch_down','max_queue_time','max_request_time'): req = cfg.getint(cs, k) - limit = cfg.getint('global',k) - self.cfg[k] = min(req, limit) + limit = cfg.getint('limits',k) + self.__dict__[k] = min(req, limit) - def process_arriving_data(d): - + def process_arriving_data(self, d): + for packet in slip_decode(d): + (saddr, daddr) = packet_addrs(packet) + if saddr != self._ip: + raise ValueError('wrong source address %s' % saddr) + route(packet, saddr, daddr) -def process_cfg(): - global network - global ourself + def _req_cancel(self, request): + request.finish() - network = ipnetwork(cfg.get('virtual','network')) - try: - ourself = cfg.get('virtual','server') - except ConfigParser.NoOptionError: - ourself = network.hosts().next() + def _req_error(self, err, request): + self._req_cancel(request) - for cs in cfg.sections(): - if not (':' in cs or '.' in cs): continue - ci = ipaddress(cs) - if ci not in network: - raise ValueError('client %s not in network' % ci) - if ci in clients: - raise ValueError('multiple client cfg sections for %s' % ci) - clients[ci] = Client(ci, cs) + def queue_outbound(self, packet): + self._pq.append((time.monotonic(), packet)) + + def http_request(self, request): + request.setHeader('Content-Type','application/octet-stream') + reactor.callLater(self.max_request_time, self._req_cancel, request) + request.notifyFinish().addErrback(self._req_error, request) + self._rq.append(request) + self._check_outbound() + + def _check_outbound(self): + while True: + try: request = self._rq[0] + except IndexError: request = None + if request and request.finished: + self._rq.popleft() + continue + + # now request is an unfinished request, or None + try: (queuetime, packet) = self._pq[0] + except IndexError: + # no packets, oh well + break + + age = time.monotonic() - queuetime + if age > self.max_queue_time: + self._pq.popleft() + continue + + if request is None: + # no request + break + + # request, and also some non-expired packets + while True: + try: (dummy, packet) = self._pq[0] + except IndexError: break + + encoded = slip_encode(packet) + + if request.sentLength > 0: + if (request.sentLength + len(slip_delimiter) + + len(encoded) > self.max_batch_down): + break + request.write(slip_delimiter) + + request.write(encoded) + self._pq.popLeft() + + assert(request.sentLength) + self._rq.popLeft() + request.finish() + # round again, looking for more to do -class FormPage(Resource): +class IphttpResource(twisted.web.resource.Resource): def render_POST(self, request): # find client, update config, etc. - ci = ipaddress(request.args['i']) + ci = ipaddr(request.args['i']) c = clients[ci] pw = request.args['pw'] if pw != c.pw: raise ValueError('bad password') @@ -87,11 +287,93 @@ class FormPage(Resource): try: v = request.args[r] except KeyError: continue v = int(v) - c.cfg[w] = v + c.__dict__[w] = v try: d = request.args['d'] except KeyError: d = '' c.process_arriving_data(d) + c.new_request(request) + + def render_GET(self, request): + return 'hippotit' + +def start_http(): + resource = IphttpResource() + sitefactory = twisted.web.server.Site(resource) + for addrspec in cfg.get('server','addrs').split(): + try: + addr = ipaddress.IPv4Address(addrspec) + endpointfactory = twisted.internet.endpoints.TCP4ServerEndpoint + except AddressValueError: + addr = ipaddress.IPv6Address(addrspec) + endpointfactory = twisted.internet.endpoints.TCP6ServerEndpoint + ep = endpointfactory(reactor, cfg.getint('server','port'), addr) + crash_on_defer(ep.listen(sitefactory)) + +#---------- config and setup ---------- + +def process_cfg(): + global network + global host + global relay + global ipif_command + + network = ipnetwork(cfg.get('virtual','network')) + if network.num_addresses < 3 + 2: + raise ValueError('network needs at least 2^3 addresses') + + try: + host = cfg.get('virtual','host') + except NoOptionError: + host = next(network.hosts()) + + try: + relay = cfg.get('virtual','relay') + except NoOptionError: + for search in network.hosts(): + if search == host: continue + relay = search + break + + for cs in cfg.sections(): + if not (':' in cs or '.' in cs): continue + ci = ipaddr(cs) + if ci not in network: + raise ValueError('client %s not in network' % ci) + if ci in clients: + raise ValueError('multiple client cfg sections for %s' % ci) + clients[ci] = Client(ci, cs) + + global mtu + mtu = cfg.get('virtual','mtu') + + iic_vars = { } + for k in ('host','relay','mtu','network'): + iic_vars[k] = globals()[k] + + ipif_command = cfg.get('server','ipif', vars=iic_vars) + +def startup(): + global cfg + + op = OptionParser() + op.add_option('-c', '--config', dest='configfile', + default='/etc/hippottd/server.conf') + global opts + (opts, args) = op.parse_args() + if len(args): op.error('no non-option arguments please') + + twisted.logger.globalLogPublisher.addObserver(crash_on_critical) + + cfg = ConfigParser() + cfg.read_string(defcfg) + cfg.read(opts.configfile) + process_cfg() + + start_ipif() + start_http() - reactor. +startup() +reactor.run() +print('CRASHED (end)', file=sys.stderr)