dccp ccid-2: Separate option parsing from CCID processing
This patch replaces an almost identical replication of code: large parts
of dccp_parse_options() re-appeared as ccid2_ackvector() in ccid2.c.
Apart from the duplication, this caused two more problems:
1. CCIDs should not need to be concerned with parsing header options;
2. one can not assume that Ack Vectors appear as a contiguous area within an
skb, it is legal to insert other options and/or padding in between. The
current code would throw an error and stop reading in such a case.
The patch provides a new data structure and associated list housekeeping.
Only small changes were necessary to integrate with CCID-2: data structure
initialisation, adapt list traversal routine, and add call to the provided
cleanup routine.
The latter also lead to fixing the following BUG: CCID-2 so far ignored
Ack Vectors on all packets other than Ack/DataAck, which is incorrect,
since Ack Vectors can be present on any packet that has an Ack field.
Details:
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* received Ack Vectors are parsed by dccp_parse_options() alone, which passes
the result on to the CCID-specific routine ccid_hc_tx_parse_options();
* CCIDs interested in using/decoding Ack Vector information will add code
to fetch parsed Ack Vectors via this interface;
* a data structure, `struct dccp_ackvec_parsed' is provided as interface;
* this structure arranges Ack Vectors of the same skb into a FIFO order;
* a doubly-linked list is used to keep the required FIFO code small.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
5 files changed