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-rw-r--r--net/sctp/ulpqueue.c476
1 files changed, 476 insertions, 0 deletions
diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
new file mode 100644
index 000000000000..f2011e0127eb
--- /dev/null
+++ b/net/sctp/ulpqueue.c
@@ -0,0 +1,476 @@
+/* SCTP kernel reference Implementation
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001-2002 International Business Machines, Corp.
+ * 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 inline sctp_ulpevent_t * sctp_ulpqueue_reasm(sctp_ulpqueue_t *ulpq,
+ sctp_ulpevent_t *event);
+static inline sctp_ulpevent_t *sctp_ulpqueue_order(sctp_ulpqueue_t *ulpq,
+ sctp_ulpevent_t *event);
+
+/* 1st Level Abstractions */
+
+/* Create a new ULP queue. */
+sctp_ulpqueue_t *sctp_ulpqueue_new(sctp_association_t *asoc,
+ __u16 inbound, int priority)
+{
+ sctp_ulpqueue_t *ulpq;
+ size_t size;
+
+ /* Today, there is only a fixed size of storage needed for
+ * stream support, but make the interfaces acceptable for
+ * the future.
+ */
+ size = sizeof(sctp_ulpqueue_t)+sctp_ulpqueue_storage_size(inbound);
+ ulpq = kmalloc(size, priority);
+ if (!ulpq)
+ goto fail;
+ if (!sctp_ulpqueue_init(ulpq, asoc, inbound))
+ goto fail_init;
+ ulpq->malloced = 1;
+ return ulpq;
+
+fail_init:
+ kfree(ulpq);
+
+fail:
+ return NULL;
+}
+
+/* Initialize a ULP queue from a block of memory. */
+sctp_ulpqueue_t *sctp_ulpqueue_init(sctp_ulpqueue_t *ulpq,
+ sctp_association_t *asoc,
+ __u16 inbound)
+{
+ memset(ulpq,
+ sizeof(sctp_ulpqueue_t) + sctp_ulpqueue_storage_size(inbound),
+ 0x00);
+
+ ulpq->asoc = asoc;
+ spin_lock_init(&ulpq->lock);
+ skb_queue_head_init(&ulpq->reasm);
+ skb_queue_head_init(&ulpq->lobby);
+ ulpq->malloced = 0;
+
+ return ulpq;
+}
+
+/* Flush the reassembly and ordering queues. */
+void sctp_ulpqueue_flush(sctp_ulpqueue_t *ulpq)
+{
+ struct sk_buff *skb;
+ sctp_ulpevent_t *event;
+
+ while ((skb = skb_dequeue(&ulpq->lobby))) {
+ event = (sctp_ulpevent_t *) skb->cb;
+ sctp_ulpevent_free(event);
+ }
+
+ while ((skb = skb_dequeue(&ulpq->reasm))) {
+ event = (sctp_ulpevent_t *) skb->cb;
+ sctp_ulpevent_free(event);
+ }
+}
+
+/* Dispose of a ulpqueue. */
+void sctp_ulpqueue_free(sctp_ulpqueue_t *ulpq)
+{
+ sctp_ulpqueue_flush(ulpq);
+ if (ulpq->malloced)
+ kfree(ulpq);
+}
+
+/* Process an incoming DATA chunk. */
+int sctp_ulpqueue_tail_data(sctp_ulpqueue_t *ulpq, sctp_chunk_t *chunk,
+ int priority)
+{
+ struct sk_buff_head temp;
+ sctp_data_chunk_t *hdr;
+ sctp_ulpevent_t *event;
+
+ hdr = (sctp_data_chunk_t *) chunk->chunk_hdr;
+
+ /* FIXME: Instead of event being the skb clone, we really should
+ * have a new skb based chunk structure that we can convert to
+ * an event. Temporarily, I'm carrying a few chunk fields in
+ * the event to allow reassembly. Its too painful to change
+ * everything at once. --jgrimm
+ */
+ event = sctp_ulpevent_make_rcvmsg(chunk->asoc, chunk, priority);
+ if (!event)
+ return -ENOMEM;
+
+ /* Do reassembly if needed. */
+ event = sctp_ulpqueue_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, event->parent);
+
+ event = sctp_ulpqueue_order(ulpq, event);
+ }
+
+ /* Send event to the ULP. */
+ if (event)
+ sctp_ulpqueue_tail_event(ulpq, event);
+
+ return 0;
+}
+
+/* Add a new event for propogation to the ULP. */
+int sctp_ulpqueue_tail_event(sctp_ulpqueue_t *ulpq, sctp_ulpevent_t *event)
+{
+ struct sock *sk = ulpq->asoc->base.sk;
+
+ /* If the socket is just going to throw this away, do not
+ * even try to deliver it.
+ */
+ if (sk->dead || (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 harvesting multiple skbs they will be
+ * collected on a list.
+ */
+ if (event->parent->list)
+ sctp_skb_list_tail(event->parent->list, &sk->receive_queue);
+ else
+ skb_queue_tail(&sk->receive_queue, event->parent);
+
+ wake_up_interruptible(sk->sleep);
+ return 1;
+
+out_free:
+ if (event->parent->list)
+ skb_queue_purge(event->parent->list);
+ else
+ kfree_skb(event->parent);
+ return 0;
+}
+
+/* 2nd Level Abstractions */
+
+/* Helper function to store chunks that need to be reassembled. */
+static inline void sctp_ulpqueue_store_reasm(sctp_ulpqueue_t *ulpq, sctp_ulpevent_t *event)
+{
+ struct sk_buff *pos, *tmp;
+ sctp_ulpevent_t *cevent;
+ __u32 tsn, ctsn;
+ unsigned long flags __attribute ((unused));
+
+ tsn = event->sndrcvinfo.sinfo_tsn;
+
+ sctp_spin_lock_irqsave(&ulpq->reasm.lock, flags);
+
+ /* Find the right place in this list. We store them by TSN. */
+ sctp_skb_for_each(pos, &ulpq->reasm, tmp) {
+ cevent = (sctp_ulpevent_t *)pos->cb;
+ ctsn = cevent->sndrcvinfo.sinfo_tsn;
+
+ if (TSN_lt(tsn, ctsn))
+ break;
+ }
+
+ /* If the queue is empty, we have a different function to call. */
+ if (skb_peek(&ulpq->reasm))
+ __skb_insert(event->parent, pos->prev, pos, &ulpq->reasm);
+ else
+ __skb_queue_tail(&ulpq->reasm, event->parent);
+
+ sctp_spin_unlock_irqrestore(&ulpq->reasm.lock, flags);
+}
+
+/* Helper function to return an event corresponding to the reassembled
+ * datagram.
+ */
+static inline sctp_ulpevent_t *sctp_make_reassembled_event(struct sk_buff *f_frag, struct sk_buff *l_frag)
+{
+ struct sk_buff *pos;
+ sctp_ulpevent_t *event;
+ struct sk_buff *pnext;
+
+ pos = f_frag->next;
+
+ /* Set the first fragment's frag_list to point to the 2nd fragment. */
+ skb_shinfo(f_frag)->frag_list = pos;
+
+ /* Remove the first fragment from the reassembly queue. */
+ __skb_unlink(f_frag, f_frag->list);
+ do {
+ pnext = pos->next;
+
+ /* Remove the fragment from the reassembly queue. */
+ __skb_unlink(pos, pos->list);
+
+ /* Break if we have reached the last fragment. */
+ if (pos == l_frag)
+ break;
+
+ pos->next = pnext;
+ pos = pnext;
+ } while (1);
+
+ event = (sctp_ulpevent_t *) f_frag->cb;
+
+ 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 sctp_ulpevent_t *sctp_ulpqueue_retrieve_reassembled(sctp_ulpqueue_t *ulpq)
+{
+ struct sk_buff *pos, *tmp;
+ sctp_ulpevent_t *cevent;
+ struct sk_buff *first_frag = NULL;
+ __u32 ctsn, next_tsn;
+ unsigned long flags __attribute ((unused));
+ sctp_ulpevent_t *retval = NULL;
+
+ /* 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;
+
+ sctp_spin_lock_irqsave(&ulpq->reasm.lock, flags);
+
+ /* 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.
+ */
+ sctp_skb_for_each(pos, &ulpq->reasm, tmp) {
+ cevent = (sctp_ulpevent_t *) pos->cb;
+ ctsn = cevent->sndrcvinfo.sinfo_tsn;
+
+ switch (cevent->chunk_flags & SCTP_DATA_FRAG_MASK) {
+ case SCTP_DATA_FIRST_FRAG:
+ first_frag = pos;
+ next_tsn = ctsn + 1;
+ break;
+
+ case SCTP_DATA_MIDDLE_FRAG:
+ if ((first_frag) && (ctsn == next_tsn))
+ next_tsn++;
+ else
+ first_frag = NULL;
+ break;
+
+ case SCTP_DATA_LAST_FRAG:
+ if ((first_frag) && (ctsn == next_tsn))
+ retval = sctp_make_reassembled_event(
+ first_frag, pos);
+ else
+ first_frag = NULL;
+ break;
+ };
+
+ /* We have the reassembled event. There is no need to look
+ * further.
+ */
+ if (retval)
+ break;
+ }
+ sctp_spin_unlock_irqrestore(&ulpq->reasm.lock, flags);
+
+ return retval;
+}
+
+/* Helper function to reassemble chunks. Hold chunks on the reasm queue that
+ * need reassembling.
+ */
+static inline sctp_ulpevent_t *sctp_ulpqueue_reasm(sctp_ulpqueue_t *ulpq,
+ sctp_ulpevent_t *event)
+{
+ sctp_ulpevent_t *retval = NULL;
+
+ /* FIXME: We should be using some new chunk structure here
+ * instead of carrying chunk fields in the event structure.
+ * This is temporary as it is too painful to change everything
+ * at once.
+ */
+
+ /* Check if this is part of a fragmented message. */
+ if (SCTP_DATA_NOT_FRAG == (event->chunk_flags & SCTP_DATA_FRAG_MASK))
+ return event;
+
+ sctp_ulpqueue_store_reasm(ulpq, event);
+ retval = sctp_ulpqueue_retrieve_reassembled(ulpq);
+
+ return retval;
+}
+
+/* Helper function to gather skbs that have possibly become
+ * ordered by an an incoming chunk.
+ */
+static inline void sctp_ulpqueue_retrieve_ordered(sctp_ulpqueue_t *ulpq,
+ sctp_ulpevent_t *event)
+{
+ struct sk_buff *pos, *tmp;
+ sctp_ulpevent_t *cevent;
+ __u16 sid, csid;
+ __u16 ssn, cssn;
+ unsigned long flags __attribute ((unused));
+
+ sid = event->sndrcvinfo.sinfo_stream;
+ ssn = event->sndrcvinfo.sinfo_ssn;
+
+ /* We are holding the chunks by stream, by SSN. */
+ sctp_spin_lock_irqsave(&ulpq->lobby.lock, flags);
+ sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
+ cevent = (sctp_ulpevent_t *) pos->cb;
+ csid = cevent->sndrcvinfo.sinfo_stream;
+ cssn = cevent->sndrcvinfo.sinfo_ssn;
+
+ /* Have we gone too far? */
+ if (csid > sid)
+ break;
+
+ /* Have we not gone far enough? */
+ if (csid < sid)
+ continue;
+
+ if (cssn != ulpq->ssn[sid])
+ break;
+
+ ulpq->ssn[sid]++;
+ __skb_unlink(pos, pos->list);
+
+ /* Attach all gathered skbs to the event. */
+ __skb_queue_tail(event->parent->list, pos);
+ }
+ sctp_spin_unlock_irqrestore(&ulpq->lobby.lock, flags);
+}
+
+/* Helper function to store chunks needing ordering. */
+static inline void sctp_ulpqueue_store_ordered(sctp_ulpqueue_t *ulpq,
+ sctp_ulpevent_t *event)
+{
+ struct sk_buff *pos, *tmp;
+ sctp_ulpevent_t *cevent;
+ __u16 sid, csid;
+ __u16 ssn, cssn;
+ unsigned long flags __attribute ((unused));
+
+ sid = event->sndrcvinfo.sinfo_stream;
+ ssn = event->sndrcvinfo.sinfo_ssn;
+
+ sctp_spin_lock_irqsave(&ulpq->lobby.lock, flags);
+
+ /* Find the right place in this list. We store them by
+ * stream ID and then by SSN.
+ */
+ sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
+ cevent = (sctp_ulpevent_t *) pos->cb;
+ csid = cevent->sndrcvinfo.sinfo_stream;
+ cssn = cevent->sndrcvinfo.sinfo_ssn;
+
+ if (csid > sid)
+ break;
+ if (csid == sid && SSN_lt(ssn, cssn))
+ break;
+ }
+
+ /* If the queue is empty, we have a different function to call. */
+ if (skb_peek(&ulpq->lobby))
+ __skb_insert(event->parent, pos->prev, pos, &ulpq->lobby);
+ else
+ __skb_queue_tail(&ulpq->lobby, event->parent);
+
+ sctp_spin_unlock_irqrestore(&ulpq->lobby.lock, flags);
+}
+
+static inline sctp_ulpevent_t *sctp_ulpqueue_order(sctp_ulpqueue_t *ulpq,
+ sctp_ulpevent_t *event)
+{
+ __u16 sid, ssn;
+
+ /* FIXME: We should be using some new chunk structure here
+ * instead of carrying chunk fields in the event structure.
+ * This is temporary as it is too painful to change everything
+ * at once.
+ */
+
+ /* Check if this message needs ordering. */
+ if (SCTP_DATA_UNORDERED & event->chunk_flags)
+ return event;
+
+ /* Note: The stream ID must be verified before this routine. */
+ sid = event->sndrcvinfo.sinfo_stream;
+ ssn = event->sndrcvinfo.sinfo_ssn;
+
+ /* Is this the expected SSN for this stream ID? */
+ if (ssn != ulpq->ssn[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_ulpqueue_store_ordered(ulpq, event);
+ return NULL;
+ }
+
+ /* Mark that the next chunk has been found. */
+ ulpq->ssn[sid]++;
+
+ /* Go find any other chunks that were waiting for
+ * ordering.
+ */
+ sctp_ulpqueue_retrieve_ordered(ulpq, event);
+
+ return event;
+}
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