Ejemplo n.º 1
0
    def parse(self, data, negotiated):
        if not data:
            return self

        # We do not care if the attribute are transitive or not as we do not redistribute
        flag = Attribute.Flag(ord(data[0]))
        aid = Attribute.CODE(ord(data[1]))

        if flag & Attribute.Flag.EXTENDED_LENGTH:
            length = unpack('!H', data[2:4])[0]
            offset = 4
        else:
            length = ord(data[2])
            offset = 3

        data = data[offset:]
        left = data[length:]
        attribute = data[:length]

        logger = Logger()
        logger.parser(LazyAttribute(flag, aid, length, data[:length]))

        # remove the PARTIAL bit before comparaison if the attribute is optional
        if aid in Attribute.attributes_optional:
            flag &= Attribute.Flag.MASK_PARTIAL & 0xFF
            # flag &= ~Attribute.Flag.PARTIAL & 0xFF  # cleaner than above (python use signed integer for ~)

        # handle the attribute if we know it
        if Attribute.registered(aid, flag):
            self.add(Attribute.unpack(aid, flag, attribute, negotiated))
            return self.parse(left, negotiated)
        # XXX: FIXME: we could use a fallback function here like capability

        # if we know the attribute but the flag is not what the RFC says. ignore it.
        if aid in Attribute.attributes_known:
            logger.parser(
                'invalid flag for attribute %s (flag 0x%02X, aid 0x%02X)' %
                (Attribute.CODE.names.get(aid, 'unset'), flag, aid))
            return self.parse(left, negotiated)

        # it is an unknown transitive attribute we need to pass on
        if flag & Attribute.Flag.TRANSITIVE:
            logger.parser(
                'unknown transitive attribute (flag 0x%02X, aid 0x%02X)' %
                (flag, aid))
            self.add(
                GenericAttribute(aid, flag | Attribute.Flag.PARTIAL,
                                 attribute), attribute)
            return self.parse(left, negotiated)

        # it is an unknown non-transitive attribute we can ignore.
        logger.parser(
            'ignoring unknown non-transitive attribute (flag 0x%02X, aid 0x%02X)'
            % (flag, aid))
        return self.parse(left, negotiated)
Ejemplo n.º 2
0
    def parse(self, data, negotiated):
        if not data:
            return self

        try:
            # We do not care if the attribute are transitive or not as we do not redistribute
            flag = Attribute.Flag(ord(data[0]))
            aid = Attribute.CODE(ord(data[1]))
        except IndexError:
            self.add(TreatAsWithdraw())
            return self

        try:
            offset = 3
            length = ord(data[2])

            if flag & Attribute.Flag.EXTENDED_LENGTH:
                offset = 4
                length = (length << 8) + ord(data[3])
        except IndexError:
            self.add(TreatAsWithdraw(aid))
            return self

        data = data[offset:]
        left = data[length:]
        attribute = data[:length]

        logger = Logger()
        logger.parser(LazyAttribute(flag, aid, length, data[:length]))

        # remove the PARTIAL bit before comparaison if the attribute is optional
        if aid in Attribute.attributes_optional:
            flag &= Attribute.Flag.MASK_PARTIAL & 0xFF
            # flag &= ~Attribute.Flag.PARTIAL & 0xFF  # cleaner than above (python use signed integer for ~)

        if aid in self:
            if aid in self.NO_DUPLICATE:
                raise Notify(
                    3, 1, 'multiple attribute for %s' %
                    str(Attribute.CODE(attribute.ID)))

            logger.parser(
                'duplicate attribute %s (flag 0x%02X, aid 0x%02X) skipping' %
                (Attribute.CODE.names.get(aid, 'unset'), flag, aid))
            return self.parse(left, negotiated)

        # handle the attribute if we know it
        if Attribute.registered(aid, flag):
            if length == 0 and aid not in self.VALID_ZERO:
                self.add(TreatAsWithdraw(aid))
                return self.parse(left, negotiated)

            try:
                decoded = Attribute.unpack(aid, flag, attribute, negotiated)
            except IndexError, exc:
                if aid in self.TREAT_AS_WITHDRAW:
                    decoded = TreatAsWithdraw(aid)
                else:
                    raise exc
            except Notify, exc:
                if aid in self.TREAT_AS_WITHDRAW:
                    decoded = TreatAsWithdraw()
                elif aid in self.DISCARD:
                    decoded = Discard()
                else:
                    raise exc
Ejemplo n.º 3
0
    def parse(self, data, negotiated):
        if not data:
            return self

        try:
            # We do not care if the attribute are transitive or not as we do not redistribute
            flag = Attribute.Flag(ordinal(data[0]))
            aid = Attribute.CODE(ordinal(data[1]))
        except IndexError:
            self.add(TreatAsWithdraw())
            return self

        try:
            offset = 3
            length = ordinal(data[2])

            if flag & Attribute.Flag.EXTENDED_LENGTH:
                offset = 4
                length = (length << 8) + ordinal(data[3])
        except IndexError:
            self.add(TreatAsWithdraw(aid))
            return self

        data = data[offset:]
        left = data[length:]
        attribute = data[:length]

        logger = Logger()
        logger.debug(LazyAttribute(flag, aid, length, data[:length]), 'parser')

        # remove the PARTIAL bit before comparaison if the attribute is optional
        if aid in Attribute.attributes_optional:
            flag &= Attribute.Flag.MASK_PARTIAL & 0xFF
            # flag &= ~Attribute.Flag.PARTIAL & 0xFF  # cleaner than above (python use signed integer for ~)

        if aid in self:
            if aid in self.NO_DUPLICATE:
                raise Notify(
                    3, 1, 'multiple attribute for %s' %
                    str(Attribute.CODE(attribute.ID)))

            logger.debug(
                'duplicate attribute %s (flag 0x%02X, aid 0x%02X) skipping' %
                (Attribute.CODE.names.get(aid, 'unset'), flag, aid), 'parser')
            return self.parse(left, negotiated)

        # handle the attribute if we know it
        if Attribute.registered(aid, flag):
            if length == 0 and aid not in self.VALID_ZERO:
                self.add(TreatAsWithdraw(aid))
                return self.parse(left, negotiated)

            try:
                decoded = Attribute.unpack(aid, flag, attribute, negotiated)
            except IndexError as exc:
                if aid in self.TREAT_AS_WITHDRAW:
                    decoded = TreatAsWithdraw(aid)
                else:
                    raise exc
            except Notify as exc:
                if aid in self.TREAT_AS_WITHDRAW:
                    decoded = TreatAsWithdraw()
                elif aid in self.DISCARD:
                    decoded = Discard()
                else:
                    raise exc
            self.add(decoded)
            return self.parse(left, negotiated)

        # XXX: FIXME: we could use a fallback function here like capability

        # if we know the attribute but the flag is not what the RFC says.
        if aid in Attribute.attributes_known:
            if aid in self.TREAT_AS_WITHDRAW:
                logger.debug(
                    'invalid flag for attribute %s (flag 0x%02X, aid 0x%02X) treat as withdraw'
                    % (Attribute.CODE.names.get(aid, 'unset'), flag, aid),
                    'parser')
                self.add(TreatAsWithdraw())
            if aid in self.DISCARD:
                logger.debug(
                    'invalid flag for attribute %s (flag 0x%02X, aid 0x%02X) discard'
                    % (Attribute.CODE.names.get(aid, 'unset'), flag, aid),
                    'parser')
                return self.parse(left, negotiated)
            # XXX: Check if we are missing any
            logger.debug(
                'invalid flag for attribute %s (flag 0x%02X, aid 0x%02X) unspecified (should not happen)'
                % (Attribute.CODE.names.get(aid, 'unset'), flag, aid),
                'parser')
            return self.parse(left, negotiated)

        # it is an unknown transitive attribute we need to pass on
        if flag & Attribute.Flag.TRANSITIVE:
            logger.debug(
                'unknown transitive attribute (flag 0x%02X, aid 0x%02X)' %
                (flag, aid), 'parser')
            try:
                decoded = GenericAttribute(aid, flag | Attribute.Flag.PARTIAL,
                                           attribute)
            except IndexError:
                decoded = TreatAsWithdraw(aid)
            self.add(decoded, attribute)
            return self.parse(left, negotiated)

        # it is an unknown non-transitive attribute we can ignore.
        logger.debug(
            'ignoring unknown non-transitive attribute (flag 0x%02X, aid 0x%02X)'
            % (flag, aid), 'parser')
        return self.parse(left, negotiated)