Files
linux-st/net/dccp/ccids/ccid2.h
Gerrit Renker c8bf462bc5 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:
--------
 * 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>
2008-09-04 07:45:37 +02:00

87 lines
2.3 KiB
C

/*
* net/dccp/ccids/ccid2.h
*
* Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef _DCCP_CCID2_H_
#define _DCCP_CCID2_H_
#include <linux/dccp.h>
#include <linux/timer.h>
#include <linux/types.h>
#include "../ccid.h"
/* NUMDUPACK parameter from RFC 4341, p. 6 */
#define NUMDUPACK 3
struct sock;
struct ccid2_seq {
u64 ccid2s_seq;
unsigned long ccid2s_sent;
int ccid2s_acked;
struct ccid2_seq *ccid2s_prev;
struct ccid2_seq *ccid2s_next;
};
#define CCID2_SEQBUF_LEN 1024
#define CCID2_SEQBUF_MAX 128
/** struct ccid2_hc_tx_sock - CCID2 TX half connection
*
* @{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
* @packets_acked: Ack counter for deriving cwnd growth (RFC 3465)
* @lastrtt: time RTT was last measured
* @rpseq: last consecutive seqno
* @rpdupack: dupacks since rpseq
* @av_chunks: list of Ack Vectors received on current skb
*/
struct ccid2_hc_tx_sock {
u32 cwnd;
u32 ssthresh;
u32 pipe;
u32 packets_acked;
struct ccid2_seq *seqbuf[CCID2_SEQBUF_MAX];
int seqbufc;
struct ccid2_seq *seqh;
struct ccid2_seq *seqt;
long rto;
long srtt;
long rttvar;
unsigned long lastrtt;
struct timer_list rtotimer;
u64 rpseq;
int rpdupack;
unsigned long last_cong;
u64 high_ack;
struct list_head av_chunks;
};
struct ccid2_hc_rx_sock {
int data;
};
static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
{
return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
}
static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
{
return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
}
#endif /* _DCCP_CCID2_H_ */