/* 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.
* Copyright (c) 2001 Nokia, Inc.
* Copyright (c) 2001 La Monte H.P. Yarroll
*
* This abstraction carries sctp events to the ULP (sockets).
*
* This SCTP 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.
*
* This SCTP 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/slab.h>
#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 *);
static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq);
/* 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;
struct sctp_ulpevent *event;
/* 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;
sctp_ulpq_reasm_drain(ulpq);
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 receive 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 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_queue_before(&ulpq->reasm, pos, sctp_event2skb(event));
}
/* 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 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 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 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;
}
}
/*
* Drain the reassembly queue. If we just cleared parted delivery, it
* is possible that the reassembly queue will contain already reassembled
* messages. Retrieve any such messages and give them to the user.
*/
static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq)
{
struct sctp_ulpevent *event = NULL;
struct sk_buff_head temp;
if (skb_queue_empty(&ulpq->reasm))
return;
while ((event = sctp_ulpq_retrieve_reassembled(ulpq)) != NULL) {
/* Do ordering if needed. */
if ((event) && (event->msg_flags & MSG_EOR)){
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);
}
}
/* Helper function to gather skbs that have possibly become
* ordered by an an incoming chunk.
*/
static 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, cssn;
sid = event->stream;
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 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_queue_before(&ulpq->lobby, pos, sctp_event2skb(event));
}
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 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;
struct sk_buff_head *lobby = &ulpq->lobby;
__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, 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, 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);
}
/* If we didn't reap any data, see if the next expected SSN
* is next on the queue and if so, use that.
*/
if (event == NULL && pos != (struct sk_buff *)lobby) {
cevent = (struct sctp_ulpevent *) pos->cb;
csid = cevent->stream;
cssn = cevent->ssn;
if (csid == sid && cssn == sctp_ssn_peek(in, csid)) {
sctp_ssn_next(in, csid);
__skb_unlink(pos, lobby);
__skb_queue_tail(&temp, pos);
event = sctp_skb2event(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);
}
static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
struct sk_buff_head *list, __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(list)) != 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 ordering queue. */
static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed)
{
return sctp_ulpq_renege_list(ulpq, &ulpq->lobby, needed);
}
/* Renege 'needed' bytes from the reassembly queue. */
static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed)
{
return sctp_ulpq_renege_list(ulpq, &ulpq->reasm, needed);
}
/* 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_mem_reclaim(asoc->base.sk);
}
/* 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);
}
