Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1132 insertions, 0 deletions

diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
new file mode 100644
index 000000000..0a8510a0c
--- /dev/null
+++ b/net/sctp/ulpqueue.c
@@ -0,0 +1,1132 @@
+// 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.
+ * Copyright (c) 2001 Nokia, Inc.
+ * Copyright (c) 2001 La Monte H.P. Yarroll
+ *
+ * This abstraction carries sctp events to the ULP (sockets).
+ *
+ * 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>
+ *    Sridhar Samudrala     <sri@us.ibm.com>
+ */
+
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/busy_poll.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->reasm_uo);
+	skb_queue_head_init(&ulpq->lobby);
+	ulpq->pd_mode  = 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);
+	}
+
+	while ((skb = __skb_dequeue(&ulpq->reasm_uo)) != 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);
+}
+
+/* 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;
+	int event_eor = 0;
+
+	/* Create an event from the incoming chunk. */
+	event = sctp_ulpevent_make_rcvmsg(chunk->asoc, chunk, gfp);
+	if (!event)
+		return -ENOMEM;
+
+	event->ssn = ntohs(chunk->subh.data_hdr->ssn);
+	event->ppid = chunk->subh.data_hdr->ppid;
+
+	/* Do reassembly if needed.  */
+	event = sctp_ulpq_reasm(ulpq, event);
+
+	/* Do ordering if needed.  */
+	if (event) {
+		/* Create a temporary list to collect chunks on.  */
+		skb_queue_head_init(&temp);
+		__skb_queue_tail(&temp, sctp_event2skb(event));
+
+		if (event->msg_flags & MSG_EOR)
+			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) {
+		event_eor = (event->msg_flags & MSG_EOR) ? 1 : 0;
+		sctp_ulpq_tail_event(ulpq, &temp);
+	}
+
+	return event_eor;
+}
+
+/* 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)) {
+			skb_queue_splice_tail_init(&sp->pd_lobby,
+						   &sk->sk_receive_queue);
+			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);
+}
+
+int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sk_buff_head *skb_list)
+{
+	struct sock *sk = ulpq->asoc->base.sk;
+	struct sctp_sock *sp = sctp_sk(sk);
+	struct sctp_ulpevent *event;
+	struct sk_buff_head *queue;
+	struct sk_buff *skb;
+	int clear_pd = 0;
+
+	skb = __skb_peek(skb_list);
+	event = sctp_skb2event(skb);
+
+	/* If the socket is just going to throw this away, do not
+	 * even try to deliver it.
+	 */
+	if (sk->sk_shutdown & RCV_SHUTDOWN &&
+	    (sk->sk_shutdown & SEND_SHUTDOWN ||
+	     !sctp_ulpevent_is_notification(event)))
+		goto out_free;
+
+	if (!sctp_ulpevent_is_notification(event)) {
+		sk_mark_napi_id(sk, skb);
+		sk_incoming_cpu_update(sk);
+	}
+	/* Check if the user wishes to receive this event.  */
+	if (!sctp_ulpevent_is_enabled(event, ulpq->asoc->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(&sp->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 = &sp->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 (sp->frag_interleave)
+				queue = &sk->sk_receive_queue;
+			else
+				queue = &sp->pd_lobby;
+		}
+	}
+
+	skb_queue_splice_tail_init(skb_list, queue);
+
+	/* 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 && !sp->data_ready_signalled) {
+		if (!sock_owned_by_user(sk))
+			sp->data_ready_signalled = 1;
+		sk->sk_data_ready(sk);
+	}
+	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.
+ */
+struct sctp_ulpevent *sctp_make_reassembled_event(struct net *net,
+						  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(net, 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 (skb_queue_is_first(&ulpq->reasm, pos)) {
+			    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(asoc->base.net,
+							     &ulpq->reasm,
+							     pd_first, pd_last);
+			if (retval)
+				sctp_ulpq_set_pd(ulpq);
+		}
+	}
+done:
+	return retval;
+found:
+	retval = sctp_make_reassembled_event(ulpq->asoc->base.net,
+					     &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_FIRST_FRAG:
+			if (!first_frag)
+				return NULL;
+			goto done;
+		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++;
+				last_frag = pos;
+			} 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->asoc->base.net, &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;
+
+		case SCTP_DATA_LAST_FRAG:
+			if (!first_frag)
+				return NULL;
+			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->asoc->base.net, &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;
+
+	if (skb_queue_empty(&ulpq->reasm))
+		return;
+
+	while ((event = sctp_ulpq_retrieve_reassembled(ulpq)) != NULL) {
+		struct sk_buff_head temp;
+
+		skb_queue_head_init(&temp);
+		__skb_queue_tail(&temp, sctp_event2skb(event));
+
+		/* Do ordering if needed.  */
+		if (event->msg_flags & MSG_EOR)
+			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, &temp);
+	}
+}
+
+
+/* Helper function to gather skbs that have possibly become
+ * ordered by 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 *stream;
+	__u16 sid, csid, cssn;
+
+	sid = event->stream;
+	stream  = &ulpq->asoc->stream;
+
+	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(stream, in, sid))
+			break;
+
+		/* Found it, so mark in the stream. */
+		sctp_ssn_next(stream, 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 *stream;
+
+	/* Check if this message needs ordering.  */
+	if (event->msg_flags & SCTP_DATA_UNORDERED)
+		return event;
+
+	/* Note: The stream ID must be verified before this routine.  */
+	sid = event->stream;
+	ssn = event->ssn;
+	stream  = &ulpq->asoc->stream;
+
+	/* Is this the expected SSN for this stream ID?  */
+	if (ssn != sctp_ssn_peek(stream, 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(stream, 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 *stream;
+	struct sk_buff_head temp;
+	struct sk_buff_head *lobby = &ulpq->lobby;
+	__u16 csid, cssn;
+
+	stream = &ulpq->asoc->stream;
+
+	/* 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(stream, 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(stream, in, csid)) {
+			sctp_ssn_next(stream, 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, &temp);
+	}
+}
+
+/* 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 *stream;
+
+	/* Note: The stream ID must be verified before this routine.  */
+	stream  = &ulpq->asoc->stream;
+
+	/* Is this an old SSN?  If so ignore. */
+	if (SSN_lt(ssn, sctp_ssn_peek(stream, in, sid)))
+		return;
+
+	/* Mark that we are no longer expecting this SSN or lower. */
+	sctp_ssn_skip(stream, in, sid, ssn);
+
+	/* Go find any other chunks that were waiting for
+	 * ordering and deliver them if needed.
+	 */
+	sctp_ulpq_reap_ordered(ulpq, sid);
+}
+
+__u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq, struct sk_buff_head *list,
+			    __u16 needed)
+{
+	__u16 freed = 0;
+	__u32 tsn, last_tsn;
+	struct sk_buff *skb, *flist, *last;
+	struct sctp_ulpevent *event;
+	struct sctp_tsnmap *tsnmap;
+
+	tsnmap = &ulpq->asoc->peer.tsn_map;
+
+	while ((skb = skb_peek_tail(list)) != NULL) {
+		event = sctp_skb2event(skb);
+		tsn = event->tsn;
+
+		/* Don't renege below the Cumulative TSN ACK Point. */
+		if (TSN_lte(tsn, sctp_tsnmap_get_ctsn(tsnmap)))
+			break;
+
+		/* Events in ordering queue may have multiple fragments
+		 * corresponding to additional TSNs.  Sum the total
+		 * freed space; find the last TSN.
+		 */
+		freed += skb_headlen(skb);
+		flist = skb_shinfo(skb)->frag_list;
+		for (last = flist; flist; flist = flist->next) {
+			last = flist;
+			freed += skb_headlen(last);
+		}
+		if (last)
+			last_tsn = sctp_skb2event(last)->tsn;
+		else
+			last_tsn = tsn;
+
+		/* Unlink the event, then renege all applicable TSNs. */
+		__skb_unlink(skb, list);
+		sctp_ulpevent_free(event);
+		while (TSN_lte(tsn, last_tsn)) {
+			sctp_tsnmap_renege(tsnmap, tsn);
+			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,
+				gfp_t gfp)
+{
+	struct sctp_ulpevent *event;
+	struct sctp_association *asoc;
+	struct sctp_sock *sp;
+	__u32 ctsn;
+	struct sk_buff *skb;
+
+	asoc = ulpq->asoc;
+	sp = sctp_sk(asoc->base.sk);
+
+	/* If the association is already in Partial Delivery mode
+	 * we have nothing to do.
+	 */
+	if (ulpq->pd_mode)
+		return;
+
+	/* Data must be at or below the Cumulative TSN ACK Point to
+	 * start partial delivery.
+	 */
+	skb = skb_peek(&asoc->ulpq.reasm);
+	if (skb != NULL) {
+		ctsn = sctp_skb2event(skb)->tsn;
+		if (!TSN_lte(ctsn, sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map)))
+			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) {
+			struct sk_buff_head temp;
+
+			skb_queue_head_init(&temp);
+			__skb_queue_tail(&temp, sctp_event2skb(event));
+			sctp_ulpq_tail_event(ulpq, &temp);
+			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 = ulpq->asoc;
+	__u32 freed = 0;
+	__u16 needed;
+
+	needed = ntohs(chunk->chunk_hdr->length) -
+		 sizeof(struct sctp_data_chunk);
+
+	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 (sk_rmem_schedule(asoc->base.sk, chunk->skb, needed) &&
+	    freed >= needed) {
+		int retval = sctp_ulpq_tail_data(ulpq, chunk, gfp);
+		/*
+		 * Enter partial delivery if chunk has not been
+		 * delivered; otherwise, drain the reassembly queue.
+		 */
+		if (retval <= 0)
+			sctp_ulpq_partial_delivery(ulpq, gfp);
+		else if (retval == 1)
+			sctp_ulpq_reasm_drain(ulpq);
+	}
+}
+
+/* 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 sctp_sock *sp;
+	struct sock *sk;
+
+	if (!ulpq->pd_mode)
+		return;
+
+	sk = ulpq->asoc->base.sk;
+	sp = sctp_sk(sk);
+	if (sctp_ulpevent_type_enabled(ulpq->asoc->subscribe,
+				       SCTP_PARTIAL_DELIVERY_EVENT))
+		ev = sctp_ulpevent_make_pdapi(ulpq->asoc,
+					      SCTP_PARTIAL_DELIVERY_ABORTED,
+					      0, 0, 0, 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) && !sp->data_ready_signalled) {
+		sp->data_ready_signalled = 1;
+		sk->sk_data_ready(sk);
+	}
+}