337 lines
13 KiB
Python
337 lines
13 KiB
Python
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# This file is part of Scapy
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# See http://www.secdev.org/projects/scapy for more information
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# Copyright (C) Philippe Biondi <phil@secdev.org>
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# This program is published under a GPLv2 license
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# Copyright (C) 2005 Guillaume Valadon <guedou@hongo.wide.ad.jp>
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# Arnaud Ebalard <arnaud.ebalard@eads.net>
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"""
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Routing and network interface handling for IPv6.
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"""
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#############################################################################
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# Routing/Interfaces stuff #
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#############################################################################
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from __future__ import absolute_import
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import socket
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from scapy.config import conf
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from scapy.utils6 import in6_ptop, in6_cidr2mask, in6_and, \
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in6_islladdr, in6_ismlladdr, in6_isincluded, in6_isgladdr, \
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in6_isaddr6to4, in6_ismaddr, construct_source_candidate_set, \
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get_source_addr_from_candidate_set
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from scapy.arch import read_routes6, in6_getifaddr
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from scapy.pton_ntop import inet_pton, inet_ntop
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from scapy.error import warning, log_loading
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import scapy.modules.six as six
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from scapy.utils import pretty_list
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class Route6:
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def __init__(self):
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self.resync()
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self.invalidate_cache()
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def invalidate_cache(self):
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self.cache = {}
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def flush(self):
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self.invalidate_cache()
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self.ipv6_ifaces = set()
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self.routes = []
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def resync(self):
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# TODO : At the moment, resync will drop existing Teredo routes
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# if any. Change that ...
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self.invalidate_cache()
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self.routes = read_routes6()
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self.ipv6_ifaces = set()
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for route in self.routes:
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self.ipv6_ifaces.add(route[3])
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if self.routes == []:
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log_loading.info("No IPv6 support in kernel")
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def __repr__(self):
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rtlst = []
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for net, msk, gw, iface, cset, metric in self.routes:
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rtlst.append(('%s/%i' % (net, msk),
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gw,
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(iface if isinstance(iface, six.string_types)
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else iface.description),
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", ".join(cset) if len(cset) > 0 else "",
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str(metric)))
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return pretty_list(rtlst,
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[('Destination', 'Next Hop', "Iface", "Src candidates", "Metric")], # noqa: E501
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sortBy=1)
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# Unlike Scapy's Route.make_route() function, we do not have 'host' and 'net' # noqa: E501
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# parameters. We only have a 'dst' parameter that accepts 'prefix' and
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# 'prefix/prefixlen' values.
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# WARNING: Providing a specific device will at the moment not work correctly. # noqa: E501
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def make_route(self, dst, gw=None, dev=None):
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"""Internal function : create a route for 'dst' via 'gw'.
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"""
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prefix, plen = (dst.split("/") + ["128"])[:2]
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plen = int(plen)
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if gw is None:
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gw = "::"
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if dev is None:
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dev, ifaddr, x = self.route(gw)
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else:
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# TODO: do better than that
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# replace that unique address by the list of all addresses
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lifaddr = in6_getifaddr()
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devaddrs = [x for x in lifaddr if x[2] == dev]
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ifaddr = construct_source_candidate_set(prefix, plen, devaddrs)
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self.ipv6_ifaces.add(dev)
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return (prefix, plen, gw, dev, ifaddr, 1)
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def add(self, *args, **kargs):
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"""Ex:
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add(dst="2001:db8:cafe:f000::/56")
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add(dst="2001:db8:cafe:f000::/56", gw="2001:db8:cafe::1")
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add(dst="2001:db8:cafe:f000::/64", gw="2001:db8:cafe::1", dev="eth0")
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"""
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self.invalidate_cache()
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self.routes.append(self.make_route(*args, **kargs))
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def remove_ipv6_iface(self, iface):
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"""
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Remove the network interface 'iface' from the list of interfaces
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supporting IPv6.
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"""
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if not all(r[3] == iface for r in conf.route6.routes):
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try:
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self.ipv6_ifaces.remove(iface)
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except KeyError:
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pass
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def delt(self, dst, gw=None):
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""" Ex:
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delt(dst="::/0")
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delt(dst="2001:db8:cafe:f000::/56")
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delt(dst="2001:db8:cafe:f000::/56", gw="2001:db8:deca::1")
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"""
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tmp = dst + "/128"
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dst, plen = tmp.split('/')[:2]
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dst = in6_ptop(dst)
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plen = int(plen)
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to_del = [x for x in self.routes
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if in6_ptop(x[0]) == dst and x[1] == plen]
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if gw:
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gw = in6_ptop(gw)
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to_del = [x for x in self.routes if in6_ptop(x[2]) == gw]
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if len(to_del) == 0:
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warning("No matching route found")
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elif len(to_del) > 1:
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warning("Found more than one match. Aborting.")
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else:
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i = self.routes.index(to_del[0])
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self.invalidate_cache()
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self.remove_ipv6_iface(self.routes[i][3])
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del(self.routes[i])
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def ifchange(self, iff, addr):
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the_addr, the_plen = (addr.split("/") + ["128"])[:2]
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the_plen = int(the_plen)
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naddr = inet_pton(socket.AF_INET6, the_addr)
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nmask = in6_cidr2mask(the_plen)
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the_net = inet_ntop(socket.AF_INET6, in6_and(nmask, naddr))
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for i, route in enumerate(self.routes):
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net, plen, gw, iface, addr, metric = route
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if iface != iff:
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continue
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self.ipv6_ifaces.add(iface)
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if gw == '::':
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self.routes[i] = (the_net, the_plen, gw, iface, [the_addr], metric) # noqa: E501
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else:
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self.routes[i] = (net, plen, gw, iface, [the_addr], metric)
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self.invalidate_cache()
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conf.netcache.in6_neighbor.flush()
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def ifdel(self, iff):
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""" removes all route entries that uses 'iff' interface. """
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new_routes = []
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for rt in self.routes:
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if rt[3] != iff:
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new_routes.append(rt)
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self.invalidate_cache()
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self.routes = new_routes
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self.remove_ipv6_iface(iff)
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def ifadd(self, iff, addr):
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"""
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Add an interface 'iff' with provided address into routing table.
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Ex: ifadd('eth0', '2001:bd8:cafe:1::1/64') will add following entry into # noqa: E501
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Scapy6 internal routing table:
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Destination Next Hop iface Def src @ Metric
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2001:bd8:cafe:1::/64 :: eth0 2001:bd8:cafe:1::1 1
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prefix length value can be omitted. In that case, a value of 128
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will be used.
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"""
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addr, plen = (addr.split("/") + ["128"])[:2]
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addr = in6_ptop(addr)
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plen = int(plen)
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naddr = inet_pton(socket.AF_INET6, addr)
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nmask = in6_cidr2mask(plen)
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prefix = inet_ntop(socket.AF_INET6, in6_and(nmask, naddr))
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self.invalidate_cache()
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self.routes.append((prefix, plen, '::', iff, [addr], 1))
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self.ipv6_ifaces.add(iff)
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def route(self, dst=None, dev=None, verbose=conf.verb):
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"""
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Provide best route to IPv6 destination address, based on Scapy
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internal routing table content.
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When a set of address is passed (e.g. ``2001:db8:cafe:*::1-5``) an
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address of the set is used. Be aware of that behavior when using
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wildcards in upper parts of addresses !
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If 'dst' parameter is a FQDN, name resolution is performed and result
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is used.
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if optional 'dev' parameter is provided a specific interface, filtering
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is performed to limit search to route associated to that interface.
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"""
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dst = dst or "::/0" # Enable route(None) to return default route
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# Transform "2001:db8:cafe:*::1-5:0/120" to one IPv6 address of the set
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dst = dst.split("/")[0]
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savedst = dst # In case following inet_pton() fails
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dst = dst.replace("*", "0")
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idx = dst.find("-")
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while idx >= 0:
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m = (dst[idx:] + ":").find(":")
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dst = dst[:idx] + dst[idx + m:]
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idx = dst.find("-")
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try:
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inet_pton(socket.AF_INET6, dst)
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except socket.error:
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dst = socket.getaddrinfo(savedst, None, socket.AF_INET6)[0][-1][0]
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# TODO : Check if name resolution went well
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# Choose a valid IPv6 interface while dealing with link-local addresses
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if dev is None and (in6_islladdr(dst) or in6_ismlladdr(dst)):
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dev = conf.iface # default interface
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# Check if the default interface supports IPv6!
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if dev not in self.ipv6_ifaces and self.ipv6_ifaces:
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tmp_routes = [route for route in self.routes
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if route[3] != conf.iface]
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default_routes = [route for route in tmp_routes
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if (route[0], route[1]) == ("::", 0)]
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ll_routes = [route for route in tmp_routes
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if (route[0], route[1]) == ("fe80::", 64)]
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if default_routes:
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# Fallback #1 - the first IPv6 default route
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dev = default_routes[0][3]
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elif ll_routes:
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# Fallback #2 - the first link-local prefix
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dev = ll_routes[0][3]
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else:
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# Fallback #3 - the loopback
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dev = conf.loopback_name
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warning("The conf.iface interface (%s) does not support IPv6! "
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"Using %s instead for routing!" % (conf.iface, dev))
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# Deal with dev-specific request for cache search
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k = dst
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if dev is not None:
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k = dst + "%%" + (dev if isinstance(dev, six.string_types) else dev.pcap_name) # noqa: E501
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if k in self.cache:
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return self.cache[k]
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paths = []
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# TODO : review all kinds of addresses (scope and *cast) to see
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# if we are able to cope with everything possible. I'm convinced
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# it's not the case.
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# -- arnaud
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for p, plen, gw, iface, cset, me in self.routes:
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if dev is not None and iface != dev:
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continue
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if in6_isincluded(dst, p, plen):
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paths.append((plen, me, (iface, cset, gw)))
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elif (in6_ismlladdr(dst) and in6_islladdr(p) and in6_islladdr(cset[0])): # noqa: E501
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paths.append((plen, me, (iface, cset, gw)))
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if not paths:
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if dst == "::1":
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return (conf.loopback_name, "::1", "::")
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else:
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if verbose:
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warning("No route found for IPv6 destination %s "
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"(no default route?)", dst)
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return (conf.loopback_name, "::", "::")
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# Sort with longest prefix first then use metrics as a tie-breaker
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paths.sort(key=lambda x: (-x[0], x[1]))
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best_plen = (paths[0][0], paths[0][1])
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paths = [x for x in paths if (x[0], x[1]) == best_plen]
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res = []
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for p in paths: # Here we select best source address for every route
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tmp = p[2]
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srcaddr = get_source_addr_from_candidate_set(dst, tmp[1])
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if srcaddr is not None:
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res.append((p[0], p[1], (tmp[0], srcaddr, tmp[2])))
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if res == []:
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warning("Found a route for IPv6 destination '%s', but no possible source address.", dst) # noqa: E501
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return (conf.loopback_name, "::", "::")
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# Symptom : 2 routes with same weight (our weight is plen)
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# Solution :
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# - dst is unicast global. Check if it is 6to4 and we have a source
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# 6to4 address in those available
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# - dst is link local (unicast or multicast) and multiple output
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# interfaces are available. Take main one (conf.iface)
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# - if none of the previous or ambiguity persists, be lazy and keep
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# first one
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if len(res) > 1:
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tmp = []
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if in6_isgladdr(dst) and in6_isaddr6to4(dst):
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# TODO : see if taking the longest match between dst and
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# every source addresses would provide better results
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tmp = [x for x in res if in6_isaddr6to4(x[2][1])]
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elif in6_ismaddr(dst) or in6_islladdr(dst):
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# TODO : I'm sure we are not covering all addresses. Check that
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tmp = [x for x in res if x[2][0] == conf.iface]
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if tmp:
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res = tmp
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# Fill the cache (including dev-specific request)
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k = dst
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if dev is not None:
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k = dst + "%%" + (dev if isinstance(dev, six.string_types) else dev.pcap_name) # noqa: E501
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self.cache[k] = res[0][2]
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return res[0][2]
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conf.route6 = Route6()
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