linux/include/net/sctp/tsnmap.h

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* SCTP kernel implementation
* (C) Copyright IBM Corp. 2001, 2004
* Copyright (c) 1999-2000 Cisco, Inc.
* Copyright (c) 1999-2001 Motorola, Inc.
* Copyright (c) 2001 Intel Corp.
*
* This file is part of the SCTP kernel implementation
*
* These are the definitions needed for the tsnmap type. The tsnmap is used
* to track out of order TSNs received.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <linux-sctp@vger.kernel.org>
*
* Written or modified by:
* Jon Grimm <jgrimm@us.ibm.com>
* La Monte H.P. Yarroll <piggy@acm.org>
* Karl Knutson <karl@athena.chicago.il.us>
* Sridhar Samudrala <sri@us.ibm.com>
*/
#include <net/sctp/constants.h>
#ifndef __sctp_tsnmap_h__
#define __sctp_tsnmap_h__
/* RFC 2960 12.2 Parameters necessary per association (i.e. the TCB)
* Mapping An array of bits or bytes indicating which out of
* Array order TSN's have been received (relative to the
* Last Rcvd TSN). If no gaps exist, i.e. no out of
* order packets have been received, this array
* will be set to all zero. This structure may be
* in the form of a circular buffer or bit array.
*/
struct sctp_tsnmap {
/* This array counts the number of chunks with each TSN.
* It points at one of the two buffers with which we will
* ping-pong between.
*/
unsigned long *tsn_map;
/* This is the TSN at tsn_map[0]. */
__u32 base_tsn;
/* Last Rcvd : This is the last TSN received in
* TSN : sequence. This value is set initially by
* : taking the peer's Initial TSN, received in
* : the INIT or INIT ACK chunk, and subtracting
* : one from it.
*
* Throughout most of the specification this is called the
* "Cumulative TSN ACK Point". In this case, we
* ignore the advice in 12.2 in favour of the term
* used in the bulk of the text.
*/
__u32 cumulative_tsn_ack_point;
/* This is the highest TSN we've marked. */
__u32 max_tsn_seen;
/* This is the minimum number of TSNs we can track. This corresponds
* to the size of tsn_map. Note: the overflow_map allows us to
* potentially track more than this quantity.
*/
__u16 len;
/* Data chunks pending receipt. used by SCTP_STATUS sockopt */
__u16 pending_data;
/* Record duplicate TSNs here. We clear this after
* every SACK. Store up to SCTP_MAX_DUP_TSNS worth of
* information.
*/
__u16 num_dup_tsns;
__be32 dup_tsns[SCTP_MAX_DUP_TSNS];
};
struct sctp_tsnmap_iter {
__u32 start;
};
/* Initialize a block of memory as a tsnmap. */
struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *, __u16 len,
__u32 initial_tsn, gfp_t gfp);
void sctp_tsnmap_free(struct sctp_tsnmap *map);
/* Test the tracking state of this TSN.
* Returns:
* 0 if the TSN has not yet been seen
* >0 if the TSN has been seen (duplicate)
* <0 if the TSN is invalid (too large to track)
*/
int sctp_tsnmap_check(const struct sctp_tsnmap *, __u32 tsn);
/* Mark this TSN as seen. */
sctp: be more restrictive in transport selection on bundled sacks It was noticed recently that when we send data on a transport, its possible that we might bundle a sack that arrived on a different transport. While this isn't a major problem, it does go against the SHOULD requirement in section 6.4 of RFC 2960: An endpoint SHOULD transmit reply chunks (e.g., SACK, HEARTBEAT ACK, etc.) to the same destination transport address from which it received the DATA or control chunk to which it is replying. This rule should also be followed if the endpoint is bundling DATA chunks together with the reply chunk. This patch seeks to correct that. It restricts the bundling of sack operations to only those transports which have moved the ctsn of the association forward since the last sack. By doing this we guarantee that we only bundle outbound saks on a transport that has received a chunk since the last sack. This brings us into stricter compliance with the RFC. Vlad had initially suggested that we strictly allow only sack bundling on the transport that last moved the ctsn forward. While this makes sense, I was concerned that doing so prevented us from bundling in the case where we had received chunks that moved the ctsn on multiple transports. In those cases, the RFC allows us to select any of the transports having received chunks to bundle the sack on. so I've modified the approach to allow for that, by adding a state variable to each transport that tracks weather it has moved the ctsn since the last sack. This I think keeps our behavior (and performance), close enough to our current profile that I think we can do this without a sysctl knob to enable/disable it. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Vlad Yaseivch <vyasevich@gmail.com> CC: David S. Miller <davem@davemloft.net> CC: linux-sctp@vger.kernel.org Reported-by: Michele Baldessari <michele@redhat.com> Reported-by: sorin serban <sserban@redhat.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-30 11:04:26 +08:00
int sctp_tsnmap_mark(struct sctp_tsnmap *, __u32 tsn,
struct sctp_transport *trans);
/* Mark this TSN and all lower as seen. */
void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn);
/* Retrieve the Cumulative TSN ACK Point. */
static inline __u32 sctp_tsnmap_get_ctsn(const struct sctp_tsnmap *map)
{
return map->cumulative_tsn_ack_point;
}
/* Retrieve the highest TSN we've seen. */
static inline __u32 sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap *map)
{
return map->max_tsn_seen;
}
/* How many duplicate TSNs are stored? */
static inline __u16 sctp_tsnmap_num_dups(struct sctp_tsnmap *map)
{
return map->num_dup_tsns;
}
/* Return pointer to duplicate tsn array as needed by SACK. */
static inline __be32 *sctp_tsnmap_get_dups(struct sctp_tsnmap *map)
{
map->num_dup_tsns = 0;
return map->dup_tsns;
}
/* How many gap ack blocks do we have recorded? */
__u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
struct sctp_gap_ack_block *gabs);
/* Refresh the count on pending data. */
__u16 sctp_tsnmap_pending(struct sctp_tsnmap *map);
/* Is there a gap in the TSN map? */
static inline int sctp_tsnmap_has_gap(const struct sctp_tsnmap *map)
{
return map->cumulative_tsn_ack_point != map->max_tsn_seen;
}
/* Mark a duplicate TSN. Note: limit the storage of duplicate TSN
* information.
*/
static inline void sctp_tsnmap_mark_dup(struct sctp_tsnmap *map, __u32 tsn)
{
if (map->num_dup_tsns < SCTP_MAX_DUP_TSNS)
map->dup_tsns[map->num_dup_tsns++] = htonl(tsn);
}
/* Renege a TSN that was seen. */
void sctp_tsnmap_renege(struct sctp_tsnmap *, __u32 tsn);
/* Is there a gap in the TSN map? */
int sctp_tsnmap_has_gap(const struct sctp_tsnmap *);
#endif /* __sctp_tsnmap_h__ */