You may be right. I'll check it soon. Thanks for your comments.

Olivier

Le mar. 22 nov. 2016 à 06:50, Iwase Yusuke <[email protected]> a
écrit :

> Hi Olivier,
>
> Thank you for submitting your patch!
>
> First, the patch seems to be wrapped unexpectedly when line exceeds
> 80(?) characters or so.
> Please confirm you mailer settings.
>   https://git-scm.com/docs/git-format-patch#_mua_specific_hints
>
> And, the following is some modest comments I found.
>
>
> On 2016年11月19日 05:07, Olivier Desnoë wrote:
> > This patch adds the ability to dissect and generate DHCPv6 packets. I
> > needed it to develop a simple LDRA app (as defined in RFC 6221).
> >
> > Signed-off-by: Olivier DESNOE <[email protected]>
> > ---
> > diff --git a/ryu/lib/packet/dhcp6.py b/ryu/lib/packet/dhcp6.py
> > new file mode 100644
> > index 0000000..1102305
> > --- /dev/null
> > +++ b/ryu/lib/packet/dhcp6.py
> > @@ -0,0 +1,301 @@
> > +# Copyright (C) 2016 Bouygues Telecom.
> > +#
> > +# Licensed under the Apache License, Version 2.0 (the "License");
> > +# you may not use this file except in compliance with the License.
> > +# You may obtain a copy of the License at
> > +#
> > +#    http://www.apache.org/licenses/LICENSE-2.0
> > +#
> > +# Unless required by applicable law or agreed to in writing, software
> > +# distributed under the License is distributed on an "AS IS" BASIS,
> > +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
> > +# implied.
> > +# See the License for the specific language governing permissions and
> > +# limitations under the License.
> > +
> > +"""
> > +DHCPv6 packet parser/serializer
> > +
> > +RFC 3315
> > +DHCP packet format
> > +
> > +   The following diagram illustrates the format of DHCP messages sent
> > +   between clients and servers:
> > +
> > +       0                   1                   2                   3
> > +       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > +      |    msg_type   |               transaction_id                  |
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > +      |                                                               |
> > +      .                            options                            .
> > +      .                           (variable)                          .
> > +      |                                                               |
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > +
> > +   There are two relay agent messages, which share the following format:
> > +
> > +       0                   1                   2                   3
> > +       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > +      |    msg_type   |   hop_count   |                               |
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
> > +      |                                                               |
> > +      |                         link_address                          |
> > +      |                                                               |
> > +      |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
> > +      |                               |                               |
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
> > +      |                                                               |
> > +      |                         peer_address                          |
> > +      |                                                               |
> > +      |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
> > +      |                               |                               |
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
> > +      .                                                               .
> > +      .            options (variable number and length)   ....        .
> > +      |                                                               |
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > +
> > +"""
> > +import binascii
>
> binascii is imported, but does not seem to be used.
>
>
> > +import random
> > +import struct
> > +
> > +from . import packet_base
> > +from ryu.lib import addrconv
> > +from ryu.lib import stringify
> > +
> > +# DHCPv6 message types
> > +DHCPV6_SOLICIT = 1
> > +DHCPV6_ADVERTISE = 2
> > +DHCPV6_REQUEST = 3
> > +DHCPV6_CONFIRM = 4
> > +DHCPV6_RENEW = 5
> > +DHCPV6_REBIND = 6
> > +DHCPV6_REPLY = 7
> > +DHCPV6_RELEASE = 8
> > +DHCPV6_DECLINE = 9
> > +DHCPV6_RECONFIGURE = 10
> > +DHCPV6_INFORMATION_REQUEST = 11
> > +DHCPV6_RELAY_FORW = 12
> > +DHCPV6_RELAY_REPL = 13
> > +
> > +# DHCPv6 option-codes
> > +DHCPV6_OPTION_CLIENTID = 1
> > +DHCPV6_OPTION_SERVERID = 2
> > +DHCPV6_OPTION_IA_NA = 3
> > +DHCPV6_OPTION_IA_TA = 4
> > +DHCPV6_OPTION_IAADDR = 5
> > +DHCPV6_OPTION_ORO = 6
> > +DHCPV6_OPTION_PREFERENCE = 7
> > +DHCPV6_OPTION_ELAPSED_TIME = 8
> > +DHCPV6_OPTION_RELAY_MSG = 9
> > +DHCPV6_OPTION_AUTH = 11
> > +DHCPV6_OPTION_UNICAST = 12
> > +DHCPV6_OPTION_STATUS_CODE = 13
> > +DHCPV6_OPTION_RAPID_COMMIT = 14
> > +DHCPV6_OPTION_USER_CLASS = 15
> > +DHCPV6_OPTION_VENDOR_CLASS = 16
> > +DHCPV6_OPTION_VENDOR_OPTS = 17
> > +DHCPV6_OPTION_INTERFACE_ID = 18
> > +DHCPV6_OPTION_RECONF_MSG = 19
> > +DHCPV6_OPTION_RECONF_ACCEPT = 20
> > +
> > +
> > +class dhcp6(packet_base.PacketBase):
> > +    """DHCPv6 (RFC 3315) header encoder/decoder class.
> > +
> > +    The serialized packet would looks like the ones described
> > +    in the following sections.
> > +
> > +    * RFC 3315 DHCP packet format
> > +
> > +    An instance has the following attributes at least.
> > +    Most of them are same to the on-wire counterparts but in host byte
> > order.
> > +    __init__ takes the corresponding args in this order.
> > +
> > +
> > +    ============== ====================
> > +    Attribute      Description
> > +    ============== ====================
> > +    msg_type       Identifies the DHCP message type
> > +
> > +    * For unrelayed messages only:
> > +    transaction_id The transaction ID for this message exchange.
> > +
> > +    * For relayed messages only
> > +    hop_count      Number of relay agents that have relayed this
> > +                   message.
> > +    link_address   A global or site-local address that will be used by
> > +                   the server to identify the link on which the client
> > +                   is located.
> > +    peer_address   The address of the client or relay agent from which
> > +                   the message to be relayed was received.
> > +
> > +    * For unrelayed and relayed messages:
> > +    options        Options carried in this message
> > +    ============== ====================
> > +    """
> > +    _MIN_LEN = 8
> > +    _DHCPV6_UNPACK_STR = '!I'
> > +    _DHCPV6_RELAY_UNPACK_STR = '!H16s16s'
> > +    _DHCPV6_UNPACK_STR_LEN = struct.calcsize(_DHCPV6_UNPACK_STR)
> > +    _DHCPV6_RELAY_UNPACK_STR_LEN =
> > struct.calcsize(_DHCPV6_RELAY_UNPACK_STR)
> > +    _DHCPV6_PACK_STR = '!I'
> > +    _DHCPV6_RELAY_PACK_STR = '!H16s16s'
> > +
> > +    def __init__(self, msg_type, options, transaction_id=None,
> hop_count=0,
> > +                 link_address='::', peer_address='::'):
> > +        super(dhcp6, self).__init__()
> > +        self.msg_type = msg_type
> > +        self.options = options
> > +        if transaction_id is None:
> > +            self.transaction_id = random.randint(0, 0xffffff)
> > +        else:
> > +            self.transaction_id = transaction_id
> > +        self.hop_count = hop_count
> > +        self.link_address = link_address
> > +        self.peer_address = peer_address
> > +
> > +    @classmethod
> > +    def _parser(cls, buf):
> > +        (msg_type, ) = struct.unpack_from('!B', buf)
> > +
> > +        buf = '\x00' + buf[1:]  # unpack xid as a  4-byte integer
> > +        if msg_type == DHCPV6_RELAY_FORW or msg_type ==
> DHCPV6_RELAY_REPL:
> > +            (hop_count, link_address, peer_address) \
> > +                = struct.unpack_from(cls._DHCPV6_RELAY_UNPACK_STR, buf)
> > +            length = struct.calcsize(cls._DHCPV6_RELAY_UNPACK_STR)
> > +        else:
> > +            (transaction_id, ) \
> > +                = struct.unpack_from(cls._DHCPV6_UNPACK_STR, buf)
> > +            length = struct.calcsize(cls._DHCPV6_UNPACK_STR)
> > +
> > +        if len(buf) > length:
> > +            parse_opt = options.parser(buf[length:])
> > +            length += parse_opt.options_len
> > +
> > +        if msg_type == DHCPV6_RELAY_FORW or msg_type ==
> DHCPV6_RELAY_REPL:
> > +            return (cls(msg_type, parse_opt, 0, hop_count,
> > +                        addrconv.ipv6.bin_to_text(link_address),
> > +                        addrconv.ipv6.bin_to_text(peer_address)),
> > +                    None, buf[length:])
> > +        else:
> > +            return (cls(msg_type, parse_opt, transaction_id),
> > +                    None, buf[length:])
>
> There seems to be the case that the local variables 'parse_opt',
> 'hop_count',
> 'link_address', 'peer_address' and 'transaction_id' might be referenced
> before assignment.
> e.g.) When NOT len(buf) > length, 'parse_opt' will not be initialized.
>
> Is it the rare case?
>
>
> > +
> > +    @classmethod
> > +    def parser(cls, buf):
> > +        try:
> > +            return cls._parser(buf)
> > +        except:
> > +            return None, None, buf
>
> This except statement is too broad for me.
> How about 'except struct.error'?
>
>
> > +
> > +    def serialize(self, payload=None, prev=None):
> > +        seri_opt = self.options.serialize()
> > +        if (self.msg_type == DHCPV6_RELAY_FORW or
> > +                self.msg_type == DHCPV6_RELAY_REPL):
> > +            pack_str = '%s%ds' % (self._DHCPV6_RELAY_PACK_STR,
> > +                                  self.options.options_len)
> > +            str = struct.pack(pack_str, self.hop_count,
>
> The value name 'str' seems to shadow built-in type.
> How about using 'buf' for it?
>
>
> > +
> addrconv.ipv6.text_to_bin(self.link_address),
> > +
> addrconv.ipv6.text_to_bin(self.peer_address),
> > +                              seri_opt)
> > +        else:
> > +            pack_str = '%s%ds' % (self._DHCPV6_PACK_STR,
> > +                                  self.options.options_len)
> > +            str = struct.pack(pack_str, self.transaction_id, seri_opt)
> > +        str = struct.pack('!B', self.msg_type) + str[1:]
> > +        return str
> > +
> > +
> > +class options(stringify.StringifyMixin):
> > +    """DHCP (RFC 3315) options encoder/decoder class.
> > +
> > +    This is used with ryu.lib.packet.dhcp6.dhcp6.
> > +
> > +    """
> > +
> > +    def __init__(self, option_list=None, options_len=0):
> > +        super(options, self).__init__()
> > +        if option_list is None:
> > +            self.option_list = []
> > +        else:
> > +            self.option_list = option_list
> > +        self.options_len = options_len
> > +
> > +    @classmethod
> > +    def parser(cls, buf):
> > +        opt_parse_list = []
> > +        offset = 0
> > +        while len(buf) > offset:
> > +            opt_buf = buf[offset:]
> > +            opt = option.parser(opt_buf)
> > +            opt_parse_list.append(opt)
> > +            offset += opt.length + 4
> > +        return cls(opt_parse_list, len(buf))
> > +
> > +    def serialize(self):
> > +        seri_opt = ""
> > +        for opt in self.option_list:
> > +            seri_opt += opt.serialize()
> > +        if self.options_len == 0:
> > +            self.options_len = len(seri_opt)
> > +        return seri_opt
> > +
> > +
> > +class option(stringify.StringifyMixin):
> > +    """DHCP (RFC 3315) options encoder/decoder class.
> > +
> > +    This is used with ryu.lib.packet.dhcp6.dhcp6.options.
> > +
> > +    An instance has the following attributes at least.
> > +    Most of them are same to the on-wire counterparts but in host byte
> > order.
> > +    __init__ takes the corresponding args in this order.
> > +
> > +   The format of DHCP options is:
> > +
> > +       0                   1                   2                   3
> > +       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > +      |          option-code          |           option-len          |
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > +      |                          option-data                          |
> > +      |                      (option-len octets)                      |
> > +      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > +
> > +      option-code   An unsigned integer identifying the specific option
> > +                    type carried in this option.
> > +
> > +      option-len    An unsigned integer giving the length of the
> > +                    option-data field in this option in octets.
> > +
> > +      option-data   The data for the option; the format of this data
> > +                    depends on the definition of the option.
> > +    """
> > +    _UNPACK_STR = '!H'
> > +    _UNPACK_STR_LEN = struct.calcsize(_UNPACK_STR)
> > +    _PACK_STR = '!HH%ds'
> > +
> > +    def __init__(self, code, data, length=0):
> > +        super(option, self).__init__()
> > +        self.code = code
> > +        self.data = data
> > +        self.length = length
> > +
> > +    @classmethod
> > +    def parser(cls, buf):
> > +        code = struct.unpack_from(cls._UNPACK_STR, buf)[0]
> > +        buf = buf[cls._UNPACK_STR_LEN:]
> > +        length = struct.unpack_from(cls._UNPACK_STR, buf)[0]
> > +        buf = buf[cls._UNPACK_STR_LEN:]
> > +        value_unpack_str = '%ds' % length
> > +        data = struct.unpack_from(value_unpack_str, buf)[0]
> > +        return cls(code, data, length)
> > +
> > +    def serialize(self):
> > +        if self.length == 0:
> > +            self.length = len(self.data)
> > +        options_pack_str = self._PACK_STR % self.length
> > +        return struct.pack(options_pack_str, self.code, self.length,
> > self.data)
> > diff --git a/ryu/lib/packet/udp.py b/ryu/lib/packet/udp.py
> > index f39fb90..064263c 100644
> > --- a/ryu/lib/packet/udp.py
> > +++ b/ryu/lib/packet/udp.py
> > @@ -18,6 +18,7 @@ import struct
> >  from . import packet_base
> >  from . import packet_utils
> >  from . import dhcp
> > +from . import dhcp6
> >  from . import vxlan
> >
> >
> > @@ -53,10 +54,12 @@ class udp(packet_base.PacketBase):
> >      @staticmethod
> >      def get_packet_type(src_port, dst_port):
> >          if ((src_port == 68 and dst_port == 67) or
> > -            (src_port == 67 and dst_port == 68) or
> > -            (src_port == 67 and
> > -             dst_port == 67)):
> > +                (src_port == 67 and dst_port == 68) or
> > +                (src_port == 67 and dst_port == 67)):
> >              return dhcp.dhcp
> > +        if (((src_port == 546 or src_port == 547) and dst_port == 547)
> or
> > +                (src_port == 547 and (dst_port == 546 or dst_port ==
> > 547))):
> > +            return dhcp6.dhcp6
> >          if (dst_port == vxlan.UDP_DST_PORT or
> >                  dst_port == vxlan.UDP_DST_PORT_OLD):
> >              return vxlan.vxlan
> >
> >
> >
> >
> ------------------------------------------------------------------------------
> >
> >
> >
> > _______________________________________________
> > Ryu-devel mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/ryu-devel
> >
>
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