> -----Original Message-----
> From: Eddie Kohler [mailto:koh...@cs.ucla.edu]
> Sent: Monday, February 28, 2011 2:41 PM
> To: Dan Wing
> Cc: ''dccp' working group'; draft-ietf-dccp-udpen...@tools.ietf.org
> Subject: Re: [dccp] WGLC for draft-ietf-dccp-udpencap
>
> A nit
>
> On 02/28/2011 01:40 PM, Dan Wing wrote:
> > 6. The "Encapsulated Port Reuse" is defined in a section titled
> > "DCCP Reset", which is confusing. Please fix.
> >
> > 7. The "Encapsulated Port Reuse" seems very scary, as I could
> > spoof it -- it contains only three bytes: the DCCP packet type
> > (1 byte) and UDP port number (2 bytes). This is insufficient
> > considering its impact to an ongoing DCCP connection. More
> > information needs to be included in the payload to prevent
> > off-path attackers from abusing this.
>
> Think this is a DCCP misunderstanding. Encapsulated Port Reuse is a
> subtype
> of the DCCP-Reset packet type. This Reset packet type, which is *not*
> particularly easy to spoof due to seqno checks and such, includes
> several
> subtype fields, namely Reason (Encapsulated Port Reuse) and 3 data
> bytes,
> which are defined as above.
Ah. That does make more sense. Thanks.
So, taking the diagram in section 3,
+-----------------------------------+
| IP Header (IPv4 or IPv6) | Variable length
+-----------------------------------+
| UDP Header | 8 bytes
+-----------------------------------+
| DCCP Generic Header | 12 or 16 bytes
+-----------------------------------+
| Additional (type-specific) Fields | Variable length (could be 0)
+-----------------------------------+
| DCCP Options | Variable length (could be 0)
+-----------------------------------+
| Application Data Area | Variable length (could be 0)
+-----------------------------------+
the 'Encapsulated Port Reuse' error is a field value within the DCCP Generic
Header, and would be registered with
http://www.iana.org/assignments/dccp-parameters/dccp-parameters.xml#dccp-parameters-2
Ok, thanks for clarifying that.
-d
