Provide best route to IPv6 destination address, based on Scapy
        internal routing table content.

        When a set of address is passed (e.g. 2001:db8:cafe:*::1-5) an address
        of the set is used. Be aware of that behavior when using wildcards in
        upper parts of addresses !

        If 'dst' parameter is a FQDN, name resolution is performed and result
        is used.

        if optional 'dev' parameter is provided a specific interface, filtering
        is performed to limit search to route associated to that interface.

def route(self, dst=None, dev=None, verbose=conf.verb):
        """
        Provide best route to IPv6 destination address, based on Scapy
        internal routing table content.

        When a set of address is passed (e.g. 2001:db8:cafe:*::1-5) an address
        of the set is used. Be aware of that behavior when using wildcards in
        upper parts of addresses !

        If 'dst' parameter is a FQDN, name resolution is performed and result
        is used.

        if optional 'dev' parameter is provided a specific interface, filtering
        is performed to limit search to route associated to that interface.
        """
        dst = dst or "::/0"  # Enable route(None) to return default route
        # Transform "2001:db8:cafe:*::1-5:0/120" to one IPv6 address of the set
        dst = dst.split("/")[0]
        savedst = dst  # In case following inet_pton() fails
        dst = dst.replace("*", "0")
        idx = dst.find("-")
        while idx >= 0:
            m = (dst[idx:] + ":").find(":")
            dst = dst[:idx] + dst[idx + m:]
            idx = dst.find("-")

        try:
            inet_pton(socket.AF_INET6, dst)
        except socket.error:
            dst = socket.getaddrinfo(savedst, None, socket.AF_INET6)[0][-1][0]
            # TODO : Check if name resolution went well

        # Use the default interface while dealing with link-local addresses
        if dev is None and (in6_islladdr(dst) or in6_ismlladdr(dst)):
            dev = conf.iface

        # Deal with dev-specific request for cache search
        k = dst
        if dev is not None:
            k = dst + "%%" + (dev if isinstance(dev, six.string_types) else dev.pcap_name)  # noqa: E501
        if k in self.cache:
            return self.cache[k]

        paths = []

        # TODO : review all kinds of addresses (scope and *cast) to see
        #        if we are able to cope with everything possible. I'm convinced
        #        it's not the case.
        # -- arnaud
        for p, plen, gw, iface, cset, me in self.routes:
            if dev is not None and iface != dev:
                continue
            if in6_isincluded(dst, p, plen):
                paths.append((plen, me, (iface, cset, gw)))
            elif (in6_ismlladdr(dst) and in6_islladdr(p) and in6_islladdr(cset[0])):  # noqa: E501
                paths.append((plen, me, (iface, cset, gw)))

        if not paths:
            if verbose:
                warning("No route found for IPv6 destination %s "
                        "(no default route?)", dst)
            return (scapy.consts.LOOPBACK_INTERFACE, "::", "::")

        # Sort with longest prefix first then use metrics as a tie-breaker
        paths.sort(key=lambda x: (-x[0], x[1]))

        best_plen = (paths[0][0], paths[0][1])
        paths = [x for x in paths if (x[0], x[1]) == best_plen]

        res = []
        for p in paths:  # Here we select best source address for every route
            tmp = p[2]
            srcaddr = get_source_addr_from_candidate_set(dst, tmp[1])
            if srcaddr is not None:
                res.append((p[0], p[1], (tmp[0], srcaddr, tmp[2])))

        if res == []:
            warning("Found a route for IPv6 destination '%s', but no possible source address.", dst)  # noqa: E501
            return (scapy.consts.LOOPBACK_INTERFACE, "::", "::")

        # Symptom  : 2 routes with same weight (our weight is plen)
        # Solution :
        #  - dst is unicast global. Check if it is 6to4 and we have a source
        #    6to4 address in those available
        #  - dst is link local (unicast or multicast) and multiple output
        #    interfaces are available. Take main one (conf.iface6)
        #  - if none of the previous or ambiguity persists, be lazy and keep
        #    first one

        if len(res) > 1:
            tmp = []
            if in6_isgladdr(dst) and in6_isaddr6to4(dst):
                # TODO : see if taking the longest match between dst and
                #        every source addresses would provide better results
                tmp = [x for x in res if in6_isaddr6to4(x[2][1])]
            elif in6_ismaddr(dst) or in6_islladdr(dst):
                # TODO : I'm sure we are not covering all addresses. Check that
                tmp = [x for x in res if x[2][0] == conf.iface6]

            if tmp:
                res = tmp

        # Fill the cache (including dev-specific request)
        k = dst
        if dev is not None:
            k = dst + "%%" + (dev if isinstance(dev, six.string_types) else dev.pcap_name)  # noqa: E501
        self.cache[k] = res[0][2]

        return res[0][2]