linux/net/sctp/ulpqueue.c
Neil Horman 4d93df0abd [SCTP]: Rewrite of sctp buffer management code
This patch introduces autotuning to the sctp buffer management code
similar to the TCP.  The buffer space can be grown if the advertised
receive window still has room.  This might happen if small message
sizes are used, which is common in telecom environmens.
New tunables are introduced that provide limits to buffer growth
and memory pressure is entered if to much buffer spaces is used.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:48:09 -07:00

1060 lines
27 KiB
C

/* SCTP kernel reference Implementation
* (C) Copyright IBM Corp. 2001, 2004
* Copyright (c) 1999-2000 Cisco, Inc.
* Copyright (c) 1999-2001 Motorola, Inc.
* Copyright (c) 2001 Intel Corp.
* Copyright (c) 2001 Nokia, Inc.
* Copyright (c) 2001 La Monte H.P. Yarroll
*
* This abstraction carries sctp events to the ULP (sockets).
*
* The SCTP reference implementation 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, or (at your option)
* any later version.
*
* The SCTP reference implementation 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 GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <lksctp-developers@lists.sourceforge.net>
*
* Or submit a bug report through the following website:
* http://www.sf.net/projects/lksctp
*
* Written or modified by:
* Jon Grimm <jgrimm@us.ibm.com>
* La Monte H.P. Yarroll <piggy@acm.org>
* Sridhar Samudrala <sri@us.ibm.com>
*
* Any bugs reported given to us we will try to fix... any fixes shared will
* be incorporated into the next SCTP release.
*/
#include <linux/types.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/sctp/structs.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
/* Forward declarations for internal helpers. */
static struct sctp_ulpevent * sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
struct sctp_ulpevent *);
static struct sctp_ulpevent * sctp_ulpq_order(struct sctp_ulpq *,
struct sctp_ulpevent *);
/* 1st Level Abstractions */
/* Initialize a ULP queue from a block of memory. */
struct sctp_ulpq *sctp_ulpq_init(struct sctp_ulpq *ulpq,
struct sctp_association *asoc)
{
memset(ulpq, 0, sizeof(struct sctp_ulpq));
ulpq->asoc = asoc;
skb_queue_head_init(&ulpq->reasm);
skb_queue_head_init(&ulpq->lobby);
ulpq->pd_mode = 0;
ulpq->malloced = 0;
return ulpq;
}
/* Flush the reassembly and ordering queues. */
void sctp_ulpq_flush(struct sctp_ulpq *ulpq)
{
struct sk_buff *skb;
struct sctp_ulpevent *event;
while ((skb = __skb_dequeue(&ulpq->lobby)) != NULL) {
event = sctp_skb2event(skb);
sctp_ulpevent_free(event);
}
while ((skb = __skb_dequeue(&ulpq->reasm)) != NULL) {
event = sctp_skb2event(skb);
sctp_ulpevent_free(event);
}
}
/* Dispose of a ulpqueue. */
void sctp_ulpq_free(struct sctp_ulpq *ulpq)
{
sctp_ulpq_flush(ulpq);
if (ulpq->malloced)
kfree(ulpq);
}
/* Process an incoming DATA chunk. */
int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
gfp_t gfp)
{
struct sk_buff_head temp;
sctp_data_chunk_t *hdr;
struct sctp_ulpevent *event;
hdr = (sctp_data_chunk_t *) chunk->chunk_hdr;
/* Create an event from the incoming chunk. */
event = sctp_ulpevent_make_rcvmsg(chunk->asoc, chunk, gfp);
if (!event)
return -ENOMEM;
/* Do reassembly if needed. */
event = sctp_ulpq_reasm(ulpq, event);
/* Do ordering if needed. */
if ((event) && (event->msg_flags & MSG_EOR)){
/* Create a temporary list to collect chunks on. */
skb_queue_head_init(&temp);
__skb_queue_tail(&temp, sctp_event2skb(event));
event = sctp_ulpq_order(ulpq, event);
}
/* Send event to the ULP. 'event' is the sctp_ulpevent for
* very first SKB on the 'temp' list.
*/
if (event)
sctp_ulpq_tail_event(ulpq, event);
return 0;
}
/* Add a new event for propagation to the ULP. */
/* Clear the partial delivery mode for this socket. Note: This
* assumes that no association is currently in partial delivery mode.
*/
int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc)
{
struct sctp_sock *sp = sctp_sk(sk);
if (atomic_dec_and_test(&sp->pd_mode)) {
/* This means there are no other associations in PD, so
* we can go ahead and clear out the lobby in one shot
*/
if (!skb_queue_empty(&sp->pd_lobby)) {
struct list_head *list;
sctp_skb_list_tail(&sp->pd_lobby, &sk->sk_receive_queue);
list = (struct list_head *)&sctp_sk(sk)->pd_lobby;
INIT_LIST_HEAD(list);
return 1;
}
} else {
/* There are other associations in PD, so we only need to
* pull stuff out of the lobby that belongs to the
* associations that is exiting PD (all of its notifications
* are posted here).
*/
if (!skb_queue_empty(&sp->pd_lobby) && asoc) {
struct sk_buff *skb, *tmp;
struct sctp_ulpevent *event;
sctp_skb_for_each(skb, &sp->pd_lobby, tmp) {
event = sctp_skb2event(skb);
if (event->asoc == asoc) {
__skb_unlink(skb, &sp->pd_lobby);
__skb_queue_tail(&sk->sk_receive_queue,
skb);
}
}
}
}
return 0;
}
/* Set the pd_mode on the socket and ulpq */
static void sctp_ulpq_set_pd(struct sctp_ulpq *ulpq)
{
struct sctp_sock *sp = sctp_sk(ulpq->asoc->base.sk);
atomic_inc(&sp->pd_mode);
ulpq->pd_mode = 1;
}
/* Clear the pd_mode and restart any pending messages waiting for delivery. */
static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq)
{
ulpq->pd_mode = 0;
return sctp_clear_pd(ulpq->asoc->base.sk, ulpq->asoc);
}
/* If the SKB of 'event' is on a list, it is the first such member
* of that list.
*/
int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
{
struct sock *sk = ulpq->asoc->base.sk;
struct sk_buff_head *queue, *skb_list;
struct sk_buff *skb = sctp_event2skb(event);
int clear_pd = 0;
skb_list = (struct sk_buff_head *) skb->prev;
/* If the socket is just going to throw this away, do not
* even try to deliver it.
*/
if (sock_flag(sk, SOCK_DEAD) || (sk->sk_shutdown & RCV_SHUTDOWN))
goto out_free;
/* Check if the user wishes to receive this event. */
if (!sctp_ulpevent_is_enabled(event, &sctp_sk(sk)->subscribe))
goto out_free;
/* If we are in partial delivery mode, post to the lobby until
* partial delivery is cleared, unless, of course _this_ is
* the association the cause of the partial delivery.
*/
if (atomic_read(&sctp_sk(sk)->pd_mode) == 0) {
queue = &sk->sk_receive_queue;
} else {
if (ulpq->pd_mode) {
/* If the association is in partial delivery, we
* need to finish delivering the partially processed
* packet before passing any other data. This is
* because we don't truly support stream interleaving.
*/
if ((event->msg_flags & MSG_NOTIFICATION) ||
(SCTP_DATA_NOT_FRAG ==
(event->msg_flags & SCTP_DATA_FRAG_MASK)))
queue = &sctp_sk(sk)->pd_lobby;
else {
clear_pd = event->msg_flags & MSG_EOR;
queue = &sk->sk_receive_queue;
}
} else {
/*
* If fragment interleave is enabled, we
* can queue this to the recieve queue instead
* of the lobby.
*/
if (sctp_sk(sk)->frag_interleave)
queue = &sk->sk_receive_queue;
else
queue = &sctp_sk(sk)->pd_lobby;
}
}
/* If we are harvesting multiple skbs they will be
* collected on a list.
*/
if (skb_list)
sctp_skb_list_tail(skb_list, queue);
else
__skb_queue_tail(queue, skb);
/* Did we just complete partial delivery and need to get
* rolling again? Move pending data to the receive
* queue.
*/
if (clear_pd)
sctp_ulpq_clear_pd(ulpq);
if (queue == &sk->sk_receive_queue)
sk->sk_data_ready(sk, 0);
return 1;
out_free:
if (skb_list)
sctp_queue_purge_ulpevents(skb_list);
else
sctp_ulpevent_free(event);
return 0;
}
/* 2nd Level Abstractions */
/* Helper function to store chunks that need to be reassembled. */
static inline void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq,
struct sctp_ulpevent *event)
{
struct sk_buff *pos;
struct sctp_ulpevent *cevent;
__u32 tsn, ctsn;
tsn = event->tsn;
/* See if it belongs at the end. */
pos = skb_peek_tail(&ulpq->reasm);
if (!pos) {
__skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
return;
}
/* Short circuit just dropping it at the end. */
cevent = sctp_skb2event(pos);
ctsn = cevent->tsn;
if (TSN_lt(ctsn, tsn)) {
__skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
return;
}
/* Find the right place in this list. We store them by TSN. */
skb_queue_walk(&ulpq->reasm, pos) {
cevent = sctp_skb2event(pos);
ctsn = cevent->tsn;
if (TSN_lt(tsn, ctsn))
break;
}
/* Insert before pos. */
__skb_insert(sctp_event2skb(event), pos->prev, pos, &ulpq->reasm);
}
/* Helper function to return an event corresponding to the reassembled
* datagram.
* This routine creates a re-assembled skb given the first and last skb's
* as stored in the reassembly queue. The skb's may be non-linear if the sctp
* payload was fragmented on the way and ip had to reassemble them.
* We add the rest of skb's to the first skb's fraglist.
*/
static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff_head *queue, struct sk_buff *f_frag, struct sk_buff *l_frag)
{
struct sk_buff *pos;
struct sk_buff *new = NULL;
struct sctp_ulpevent *event;
struct sk_buff *pnext, *last;
struct sk_buff *list = skb_shinfo(f_frag)->frag_list;
/* Store the pointer to the 2nd skb */
if (f_frag == l_frag)
pos = NULL;
else
pos = f_frag->next;
/* Get the last skb in the f_frag's frag_list if present. */
for (last = list; list; last = list, list = list->next);
/* Add the list of remaining fragments to the first fragments
* frag_list.
*/
if (last)
last->next = pos;
else {
if (skb_cloned(f_frag)) {
/* This is a cloned skb, we can't just modify
* the frag_list. We need a new skb to do that.
* Instead of calling skb_unshare(), we'll do it
* ourselves since we need to delay the free.
*/
new = skb_copy(f_frag, GFP_ATOMIC);
if (!new)
return NULL; /* try again later */
sctp_skb_set_owner_r(new, f_frag->sk);
skb_shinfo(new)->frag_list = pos;
} else
skb_shinfo(f_frag)->frag_list = pos;
}
/* Remove the first fragment from the reassembly queue. */
__skb_unlink(f_frag, queue);
/* if we did unshare, then free the old skb and re-assign */
if (new) {
kfree_skb(f_frag);
f_frag = new;
}
while (pos) {
pnext = pos->next;
/* Update the len and data_len fields of the first fragment. */
f_frag->len += pos->len;
f_frag->data_len += pos->len;
/* Remove the fragment from the reassembly queue. */
__skb_unlink(pos, queue);
/* Break if we have reached the last fragment. */
if (pos == l_frag)
break;
pos->next = pnext;
pos = pnext;
}
event = sctp_skb2event(f_frag);
SCTP_INC_STATS(SCTP_MIB_REASMUSRMSGS);
return event;
}
/* Helper function to check if an incoming chunk has filled up the last
* missing fragment in a SCTP datagram and return the corresponding event.
*/
static inline struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_ulpq *ulpq)
{
struct sk_buff *pos;
struct sctp_ulpevent *cevent;
struct sk_buff *first_frag = NULL;
__u32 ctsn, next_tsn;
struct sctp_ulpevent *retval = NULL;
struct sk_buff *pd_first = NULL;
struct sk_buff *pd_last = NULL;
size_t pd_len = 0;
struct sctp_association *asoc;
u32 pd_point;
/* Initialized to 0 just to avoid compiler warning message. Will
* never be used with this value. It is referenced only after it
* is set when we find the first fragment of a message.
*/
next_tsn = 0;
/* The chunks are held in the reasm queue sorted by TSN.
* Walk through the queue sequentially and look for a sequence of
* fragmented chunks that complete a datagram.
* 'first_frag' and next_tsn are reset when we find a chunk which
* is the first fragment of a datagram. Once these 2 fields are set
* we expect to find the remaining middle fragments and the last
* fragment in order. If not, first_frag is reset to NULL and we
* start the next pass when we find another first fragment.
*
* There is a potential to do partial delivery if user sets
* SCTP_PARTIAL_DELIVERY_POINT option. Lets count some things here
* to see if can do PD.
*/
skb_queue_walk(&ulpq->reasm, pos) {
cevent = sctp_skb2event(pos);
ctsn = cevent->tsn;
switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
case SCTP_DATA_FIRST_FRAG:
/* If this "FIRST_FRAG" is the first
* element in the queue, then count it towards
* possible PD.
*/
if (pos == ulpq->reasm.next) {
pd_first = pos;
pd_last = pos;
pd_len = pos->len;
} else {
pd_first = NULL;
pd_last = NULL;
pd_len = 0;
}
first_frag = pos;
next_tsn = ctsn + 1;
break;
case SCTP_DATA_MIDDLE_FRAG:
if ((first_frag) && (ctsn == next_tsn)) {
next_tsn++;
if (pd_first) {
pd_last = pos;
pd_len += pos->len;
}
} else
first_frag = NULL;
break;
case SCTP_DATA_LAST_FRAG:
if (first_frag && (ctsn == next_tsn))
goto found;
else
first_frag = NULL;
break;
}
}
asoc = ulpq->asoc;
if (pd_first) {
/* Make sure we can enter partial deliver.
* We can trigger partial delivery only if framgent
* interleave is set, or the socket is not already
* in partial delivery.
*/
if (!sctp_sk(asoc->base.sk)->frag_interleave &&
atomic_read(&sctp_sk(asoc->base.sk)->pd_mode))
goto done;
cevent = sctp_skb2event(pd_first);
pd_point = sctp_sk(asoc->base.sk)->pd_point;
if (pd_point && pd_point <= pd_len) {
retval = sctp_make_reassembled_event(&ulpq->reasm,
pd_first,
pd_last);
if (retval)
sctp_ulpq_set_pd(ulpq);
}
}
done:
return retval;
found:
retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, pos);
if (retval)
retval->msg_flags |= MSG_EOR;
goto done;
}
/* Retrieve the next set of fragments of a partial message. */
static inline struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq *ulpq)
{
struct sk_buff *pos, *last_frag, *first_frag;
struct sctp_ulpevent *cevent;
__u32 ctsn, next_tsn;
int is_last;
struct sctp_ulpevent *retval;
/* The chunks are held in the reasm queue sorted by TSN.
* Walk through the queue sequentially and look for the first
* sequence of fragmented chunks.
*/
if (skb_queue_empty(&ulpq->reasm))
return NULL;
last_frag = first_frag = NULL;
retval = NULL;
next_tsn = 0;
is_last = 0;
skb_queue_walk(&ulpq->reasm, pos) {
cevent = sctp_skb2event(pos);
ctsn = cevent->tsn;
switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
case SCTP_DATA_MIDDLE_FRAG:
if (!first_frag) {
first_frag = pos;
next_tsn = ctsn + 1;
last_frag = pos;
} else if (next_tsn == ctsn)
next_tsn++;
else
goto done;
break;
case SCTP_DATA_LAST_FRAG:
if (!first_frag)
first_frag = pos;
else if (ctsn != next_tsn)
goto done;
last_frag = pos;
is_last = 1;
goto done;
default:
return NULL;
}
}
/* We have the reassembled event. There is no need to look
* further.
*/
done:
retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
if (retval && is_last)
retval->msg_flags |= MSG_EOR;
return retval;
}
/* Helper function to reassemble chunks. Hold chunks on the reasm queue that
* need reassembling.
*/
static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
struct sctp_ulpevent *event)
{
struct sctp_ulpevent *retval = NULL;
/* Check if this is part of a fragmented message. */
if (SCTP_DATA_NOT_FRAG == (event->msg_flags & SCTP_DATA_FRAG_MASK)) {
event->msg_flags |= MSG_EOR;
return event;
}
sctp_ulpq_store_reasm(ulpq, event);
if (!ulpq->pd_mode)
retval = sctp_ulpq_retrieve_reassembled(ulpq);
else {
__u32 ctsn, ctsnap;
/* Do not even bother unless this is the next tsn to
* be delivered.
*/
ctsn = event->tsn;
ctsnap = sctp_tsnmap_get_ctsn(&ulpq->asoc->peer.tsn_map);
if (TSN_lte(ctsn, ctsnap))
retval = sctp_ulpq_retrieve_partial(ulpq);
}
return retval;
}
/* Retrieve the first part (sequential fragments) for partial delivery. */
static inline struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *ulpq)
{
struct sk_buff *pos, *last_frag, *first_frag;
struct sctp_ulpevent *cevent;
__u32 ctsn, next_tsn;
struct sctp_ulpevent *retval;
/* The chunks are held in the reasm queue sorted by TSN.
* Walk through the queue sequentially and look for a sequence of
* fragmented chunks that start a datagram.
*/
if (skb_queue_empty(&ulpq->reasm))
return NULL;
last_frag = first_frag = NULL;
retval = NULL;
next_tsn = 0;
skb_queue_walk(&ulpq->reasm, pos) {
cevent = sctp_skb2event(pos);
ctsn = cevent->tsn;
switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
case SCTP_DATA_FIRST_FRAG:
if (!first_frag) {
first_frag = pos;
next_tsn = ctsn + 1;
last_frag = pos;
} else
goto done;
break;
case SCTP_DATA_MIDDLE_FRAG:
if (!first_frag)
return NULL;
if (ctsn == next_tsn) {
next_tsn++;
last_frag = pos;
} else
goto done;
break;
default:
return NULL;
}
}
/* We have the reassembled event. There is no need to look
* further.
*/
done:
retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
return retval;
}
/*
* Flush out stale fragments from the reassembly queue when processing
* a Forward TSN.
*
* RFC 3758, Section 3.6
*
* After receiving and processing a FORWARD TSN, the data receiver MUST
* take cautions in updating its re-assembly queue. The receiver MUST
* remove any partially reassembled message, which is still missing one
* or more TSNs earlier than or equal to the new cumulative TSN point.
* In the event that the receiver has invoked the partial delivery API,
* a notification SHOULD also be generated to inform the upper layer API
* that the message being partially delivered will NOT be completed.
*/
void sctp_ulpq_reasm_flushtsn(struct sctp_ulpq *ulpq, __u32 fwd_tsn)
{
struct sk_buff *pos, *tmp;
struct sctp_ulpevent *event;
__u32 tsn;
if (skb_queue_empty(&ulpq->reasm))
return;
skb_queue_walk_safe(&ulpq->reasm, pos, tmp) {
event = sctp_skb2event(pos);
tsn = event->tsn;
/* Since the entire message must be abandoned by the
* sender (item A3 in Section 3.5, RFC 3758), we can
* free all fragments on the list that are less then
* or equal to ctsn_point
*/
if (TSN_lte(tsn, fwd_tsn)) {
__skb_unlink(pos, &ulpq->reasm);
sctp_ulpevent_free(event);
} else
break;
}
}
/* Helper function to gather skbs that have possibly become
* ordered by an an incoming chunk.
*/
static inline void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
struct sctp_ulpevent *event)
{
struct sk_buff_head *event_list;
struct sk_buff *pos, *tmp;
struct sctp_ulpevent *cevent;
struct sctp_stream *in;
__u16 sid, csid;
__u16 ssn, cssn;
sid = event->stream;
ssn = event->ssn;
in = &ulpq->asoc->ssnmap->in;
event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev;
/* We are holding the chunks by stream, by SSN. */
sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
cevent = (struct sctp_ulpevent *) pos->cb;
csid = cevent->stream;
cssn = cevent->ssn;
/* Have we gone too far? */
if (csid > sid)
break;
/* Have we not gone far enough? */
if (csid < sid)
continue;
if (cssn != sctp_ssn_peek(in, sid))
break;
/* Found it, so mark in the ssnmap. */
sctp_ssn_next(in, sid);
__skb_unlink(pos, &ulpq->lobby);
/* Attach all gathered skbs to the event. */
__skb_queue_tail(event_list, pos);
}
}
/* Helper function to store chunks needing ordering. */
static inline void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq,
struct sctp_ulpevent *event)
{
struct sk_buff *pos;
struct sctp_ulpevent *cevent;
__u16 sid, csid;
__u16 ssn, cssn;
pos = skb_peek_tail(&ulpq->lobby);
if (!pos) {
__skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
return;
}
sid = event->stream;
ssn = event->ssn;
cevent = (struct sctp_ulpevent *) pos->cb;
csid = cevent->stream;
cssn = cevent->ssn;
if (sid > csid) {
__skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
return;
}
if ((sid == csid) && SSN_lt(cssn, ssn)) {
__skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
return;
}
/* Find the right place in this list. We store them by
* stream ID and then by SSN.
*/
skb_queue_walk(&ulpq->lobby, pos) {
cevent = (struct sctp_ulpevent *) pos->cb;
csid = cevent->stream;
cssn = cevent->ssn;
if (csid > sid)
break;
if (csid == sid && SSN_lt(ssn, cssn))
break;
}
/* Insert before pos. */
__skb_insert(sctp_event2skb(event), pos->prev, pos, &ulpq->lobby);
}
static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq,
struct sctp_ulpevent *event)
{
__u16 sid, ssn;
struct sctp_stream *in;
/* Check if this message needs ordering. */
if (SCTP_DATA_UNORDERED & event->msg_flags)
return event;
/* Note: The stream ID must be verified before this routine. */
sid = event->stream;
ssn = event->ssn;
in = &ulpq->asoc->ssnmap->in;
/* Is this the expected SSN for this stream ID? */
if (ssn != sctp_ssn_peek(in, sid)) {
/* We've received something out of order, so find where it
* needs to be placed. We order by stream and then by SSN.
*/
sctp_ulpq_store_ordered(ulpq, event);
return NULL;
}
/* Mark that the next chunk has been found. */
sctp_ssn_next(in, sid);
/* Go find any other chunks that were waiting for
* ordering.
*/
sctp_ulpq_retrieve_ordered(ulpq, event);
return event;
}
/* Helper function to gather skbs that have possibly become
* ordered by forward tsn skipping their dependencies.
*/
static inline void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq, __u16 sid)
{
struct sk_buff *pos, *tmp;
struct sctp_ulpevent *cevent;
struct sctp_ulpevent *event;
struct sctp_stream *in;
struct sk_buff_head temp;
__u16 csid, cssn;
in = &ulpq->asoc->ssnmap->in;
/* We are holding the chunks by stream, by SSN. */
skb_queue_head_init(&temp);
event = NULL;
sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
cevent = (struct sctp_ulpevent *) pos->cb;
csid = cevent->stream;
cssn = cevent->ssn;
/* Have we gone too far? */
if (csid > sid)
break;
/* Have we not gone far enough? */
if (csid < sid)
continue;
/* see if this ssn has been marked by skipping */
if (!SSN_lt(cssn, sctp_ssn_peek(in, csid)))
break;
__skb_unlink(pos, &ulpq->lobby);
if (!event)
/* Create a temporary list to collect chunks on. */
event = sctp_skb2event(pos);
/* Attach all gathered skbs to the event. */
__skb_queue_tail(&temp, pos);
}
/* Send event to the ULP. 'event' is the sctp_ulpevent for
* very first SKB on the 'temp' list.
*/
if (event) {
/* see if we have more ordered that we can deliver */
sctp_ulpq_retrieve_ordered(ulpq, event);
sctp_ulpq_tail_event(ulpq, event);
}
}
/* Skip over an SSN. This is used during the processing of
* Forwared TSN chunk to skip over the abandoned ordered data
*/
void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn)
{
struct sctp_stream *in;
/* Note: The stream ID must be verified before this routine. */
in = &ulpq->asoc->ssnmap->in;
/* Is this an old SSN? If so ignore. */
if (SSN_lt(ssn, sctp_ssn_peek(in, sid)))
return;
/* Mark that we are no longer expecting this SSN or lower. */
sctp_ssn_skip(in, sid, ssn);
/* Go find any other chunks that were waiting for
* ordering and deliver them if needed.
*/
sctp_ulpq_reap_ordered(ulpq, sid);
return;
}
/* Renege 'needed' bytes from the ordering queue. */
static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed)
{
__u16 freed = 0;
__u32 tsn;
struct sk_buff *skb;
struct sctp_ulpevent *event;
struct sctp_tsnmap *tsnmap;
tsnmap = &ulpq->asoc->peer.tsn_map;
while ((skb = __skb_dequeue_tail(&ulpq->lobby)) != NULL) {
freed += skb_headlen(skb);
event = sctp_skb2event(skb);
tsn = event->tsn;
sctp_ulpevent_free(event);
sctp_tsnmap_renege(tsnmap, tsn);
if (freed >= needed)
return freed;
}
return freed;
}
/* Renege 'needed' bytes from the reassembly queue. */
static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed)
{
__u16 freed = 0;
__u32 tsn;
struct sk_buff *skb;
struct sctp_ulpevent *event;
struct sctp_tsnmap *tsnmap;
tsnmap = &ulpq->asoc->peer.tsn_map;
/* Walk backwards through the list, reneges the newest tsns. */
while ((skb = __skb_dequeue_tail(&ulpq->reasm)) != NULL) {
freed += skb_headlen(skb);
event = sctp_skb2event(skb);
tsn = event->tsn;
sctp_ulpevent_free(event);
sctp_tsnmap_renege(tsnmap, tsn);
if (freed >= needed)
return freed;
}
return freed;
}
/* Partial deliver the first message as there is pressure on rwnd. */
void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq,
struct sctp_chunk *chunk,
gfp_t gfp)
{
struct sctp_ulpevent *event;
struct sctp_association *asoc;
struct sctp_sock *sp;
asoc = ulpq->asoc;
sp = sctp_sk(asoc->base.sk);
/* If the association is already in Partial Delivery mode
* we have noting to do.
*/
if (ulpq->pd_mode)
return;
/* If the user enabled fragment interleave socket option,
* multiple associations can enter partial delivery.
* Otherwise, we can only enter partial delivery if the
* socket is not in partial deliver mode.
*/
if (sp->frag_interleave || atomic_read(&sp->pd_mode) == 0) {
/* Is partial delivery possible? */
event = sctp_ulpq_retrieve_first(ulpq);
/* Send event to the ULP. */
if (event) {
sctp_ulpq_tail_event(ulpq, event);
sctp_ulpq_set_pd(ulpq);
return;
}
}
}
/* Renege some packets to make room for an incoming chunk. */
void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
gfp_t gfp)
{
struct sctp_association *asoc;
__u16 needed, freed;
asoc = ulpq->asoc;
if (chunk) {
needed = ntohs(chunk->chunk_hdr->length);
needed -= sizeof(sctp_data_chunk_t);
} else
needed = SCTP_DEFAULT_MAXWINDOW;
freed = 0;
if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) {
freed = sctp_ulpq_renege_order(ulpq, needed);
if (freed < needed) {
freed += sctp_ulpq_renege_frags(ulpq, needed - freed);
}
}
/* If able to free enough room, accept this chunk. */
if (chunk && (freed >= needed)) {
__u32 tsn;
tsn = ntohl(chunk->subh.data_hdr->tsn);
sctp_tsnmap_mark(&asoc->peer.tsn_map, tsn);
sctp_ulpq_tail_data(ulpq, chunk, gfp);
sctp_ulpq_partial_delivery(ulpq, chunk, gfp);
}
sk_stream_mem_reclaim(asoc->base.sk);
return;
}
/* Notify the application if an association is aborted and in
* partial delivery mode. Send up any pending received messages.
*/
void sctp_ulpq_abort_pd(struct sctp_ulpq *ulpq, gfp_t gfp)
{
struct sctp_ulpevent *ev = NULL;
struct sock *sk;
if (!ulpq->pd_mode)
return;
sk = ulpq->asoc->base.sk;
if (sctp_ulpevent_type_enabled(SCTP_PARTIAL_DELIVERY_EVENT,
&sctp_sk(sk)->subscribe))
ev = sctp_ulpevent_make_pdapi(ulpq->asoc,
SCTP_PARTIAL_DELIVERY_ABORTED,
gfp);
if (ev)
__skb_queue_tail(&sk->sk_receive_queue, sctp_event2skb(ev));
/* If there is data waiting, send it up the socket now. */
if (sctp_ulpq_clear_pd(ulpq) || ev)
sk->sk_data_ready(sk, 0);
}