commit 4300329a30f3b6aa3e390b140193dd50faa6e03f Author: aagbsn aagbsn@extc.org Date: Wed Jun 20 04:40:16 2012 -0700

4568 - Add class PluggableTransport to Bridges

Adds a class PluggableTransport and function parseExtraInfoFile() to read pluggable transports from bridge extra-info descriptors. Also adds transport support in FilteredBridgeSplitter.dumpAssignments --- lib/bridgedb/Bridges.py | 133 +++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 129 insertions(+), 4 deletions(-)

diff --git a/lib/bridgedb/Bridges.py b/lib/bridgedb/Bridges.py index 5a3949a..3d72d37 100644 --- a/lib/bridgedb/Bridges.py +++ b/lib/bridgedb/Bridges.py @@ -105,7 +105,7 @@ class Bridge: ## running,stable -- DOCDOC ## blockingCountries -- list of country codes blocking this bridge def __init__(self, nickname, ip, orport, fingerprint=None, id_digest=None, - or_addresses=None): + or_addresses=None, transports=None): """Create a new Bridge. One of fingerprint and id_digest must be set.""" self.nickname = nickname @@ -113,8 +113,11 @@ class Bridge: self.orport = orport if not or_addresses: or_addresses = {} self.or_addresses = or_addresses + if not transports: transports = [] + self.transports = transports self.running = self.stable = None self.blockingCountries = None + if id_digest is not None: assert fingerprint is None if len(id_digest) != DIGEST_LEN: @@ -142,13 +145,14 @@ class Bridge: self.nickname, self.ip, self.orport, self.fingerprint)

def getConfigLine(self, includeFingerprint=False, addressClass=None, - request=None): + request=None, transport=None): """Returns a valid bridge line for inclusion in a torrc""" #arguments: # includeFingerprint # addressClass - type of address to choose # request - a string unique to this request # e.g. email-address or uniformMap(ip) + # transport - a pluggable transport method name

if not request: request = 'default' digest = get_hmac_fn('Order-Or-Addresses')(request) @@ -157,6 +161,18 @@ class Bridge: # default address type if not addressClass: addressClass = ipaddr.IPv4Address

+ # pluggable transports + if transport: + # filter by 'methodname' + transports = filter(lambda x: transport == x.methodname, + self.transports) + # filter by 'addressClass' + transports = filter(lambda x: isinstance(x.address, addressClass), + transports) + if transports: + pt = transports[pos % len(transports)] + return pt.getTransportLine(includeFingerprint) + # filter addresses by address class addresses = filter(lambda x: isinstance(x[0], addressClass), self.or_addresses.items()) @@ -179,8 +195,6 @@ class Bridge:

def getAllConfigLines(self,includeFingerprint=False): """Generator. Iterate over all valid config lines for this bridge.""" - # warning: a bridge with large port ranges may generate thousands - # of lines of output for address,portlist in self.or_addresses.items(): if type(address) is ipaddr.IPv6Address: ip = "[%s]" % address @@ -192,6 +206,9 @@ class Bridge: yield "bridge %s:%d %s" % (ip,orport,self.fingerprint) else: yield "bridge %s:%d" % (ip,orport) + for pt in self.transports: + yield pt.getTransportLine(includeFingerprints) +

def assertOK(self): assert is_valid_ip(self.ip) @@ -352,6 +369,108 @@ def parseORAddressLine(line): if address and portlist and len(portlist): return address,portlist raise ParseORAddressError

+class PluggableTransport: + """ + an object that represents a pluggable-transport method + and a reference to the relevant bridge + """ + def __init__(self, bridge, methodname, address, port, argdict=None): + + #XXX: assert are disabled with python -O + assert isinstance(bridge, Bridge) + assert type(address) in (ipaddr.IPv4Address, ipaddr.IPv6Address) + assert type(port) is int + assert (0 < port < 65536) + assert type(methodname) is str + + self.bridge = bridge + self.address = address + self.port = port + self.methodname = methodname + if type(argdict) is dict: + self.argdict = argdict + else: self.argdict = {} + + def getTransportLine(self, includeFingerprint=False): + """ + returns a torrc bridge line for this transport + """ + if isinstance(self.address,ipaddr.IPv6Address): + address = "[%s]" % self.address + else: address = self.address + host = "bridge %s %s:%d" % (self.methodname, address, self.port) + fp = '' + if includeFingerprint: fp = "keyid=%s" % self.bridge.fingerprint + args = " ".join(["%s=%s"%(k,v) for k,v in self.argdict.items()]).strip() + return "%s %s %s" % (host, fp, args) + +def parseExtraInfoFile(f): + """ + parses lines in Bridges extra-info documents. + returns an object whose type corresponds to the + relevant set of extra-info lines. + + presently supported lines and the accompanying type are: + + { 'transport': PluggableTransport, } + + 'transport' lines (torspec.git/proposals/180-pluggable-transport.txt) + + Bridges put the 'transport' lines in their extra-info documents. + the format is: + + transport SP <methodname> SP address:port [SP arglist] NL + """ + + ID = None + for line in f: + line = line.strip() + + argdict = {} + + # do we need to skip 'opt' here? + # if line.startswith("opt "): + # line = line[4:] + + # get the bridge ID ? + if line.startswith("extra-info "): #XXX: get the router ID + line = line[11:] + (nickname, ID) = line.split() + if is_valid_fingerprint(ID): + ID = fromHex(ID) + + # get the transport line + if ID and line.startswith("transport "): + fields = line[10:].split() + # [ arglist ] field, optional + if len(fields) >= 3: + arglist = fields[2:] + # parse arglist [k=v,...k=v] as argdict {k:v,...,k:v} + argdict = {} + for arg in arglist: + try: k,v = arg.split('=') + except ValueError: continue + argdict[k] = v + + # get the required fields, method name and address + if len(fields) >= 2: + # get the method name + # Method names must be C identifiers + for regex in [re_ipv4, re_ipv6]: + try: + method_name = re.match('[_a-zA-Z][_a-zA-Z0-9]*',fields[0]).group() + m = regex.match(fields[1]) + address = ipaddr.IPAddress(m.group(1)) + port = int(m.group(2)) + yield ID, method_name, address, port, argdict + except (IndexError, ValueError, AttributeError): + # skip this line + continue + + # end of descriptor is defined how? + if ID and line.startswith("router-signature"): + ID = None + def parseStatusFile(f): """DOCDOC""" ID = None @@ -760,7 +879,9 @@ class FilteredBridgeSplitter(BridgeHolder): logging.debug("insert bridge into %s" % n)

#XXX db.insertBridgeAndGetRing ?? + # already 'assigned' by the FixedBridgeSplitter #XXX persisent mapping? + # the filters rebuild

def addRing(self, ring, ringname, filterFn, populate_from=None): """Add a ring to this splitter. @@ -804,6 +925,10 @@ class FilteredBridgeSplitter(BridgeHolder): except TypeError: desc.append(g.description)

+ # add transports + for transport in b.transports: + desc.append("transport=%s"%(transport.methodname)) + # dedupe and group desc = set(desc) grouped = dict()