Tom,
Phelan, Tom wrote:
So I suggest the next version of DCCP-NAT should say something like
this: There are two versions of the DCCP-NAT generic header. When the
UDP Checksum field is non-zero, the DCCP-NAT generic header is as
described in the current draft. The UDP Checksum covers the entire
datagram and there is no DCCP checksum. When the UDP Checksum is 0, the
DCCP-NAT generic header is extended by four bytes to encode the DCCP-NAT
checksum and checksum coverage length. The DCCP-NAT checksum covers the
8-byte UDP header, the entire DCCP-NAT header (including type-specific
fields and options) and however much of the user data that is indicated
by the checksum coverage value.
There are more details that will be needed in the next draft, but this
is the general outline. Does this work for you?
Doesn't this definition of the DCCP-NAT checksum break the NAT-friendliness?
Assuming the NAT is modifying the UDP ports being used, if the DCCP-NAT
checksum covers the UDP header, then it will be broken by the
modification made by the NAT.
regards,
Andrew
