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/* SCTP kernel reference Implementation

 * Copyright (c) 1999-2000 Cisco, Inc.

 * Copyright (c) 1999-2001 Motorola, Inc.

 * Copyright (c) 2002 International Business Machines, Corp.

 *

 * This file is part of the SCTP kernel reference Implementation

 *

 * These functions are the methods for accessing the SCTP inqueue.

 *

 * An SCTP inqueue is a queue into which you push SCTP packets

 * (which might be bundles or fragments of chunks) and out of which you

 * pop SCTP whole chunks.

 *

 * 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:

 *    La Monte H.P. Yarroll <piggy@acm.org>

 *    Karl Knutson <karl@athena.chicago.il.us>

 *

 * Any bugs reported given to us we will try to fix... any fixes shared will

 * be incorporated into the next SCTP release.

 */

#include <net/sctp/sctp.h>

#include <net/sctp/sm.h>

#include <linux/interrupt.h>

/* Initialize an SCTP inqueue.  */

void sctp_inq_init(struct sctp_inq *queue)

{

        skb_queue_head_init(&queue->in);

        queue->in_progress = NULL;

        /* Create a task for delivering data.  */

        INIT_LIST_HEAD(&queue->immediate.list);

        queue->immediate.sync = 0;

        queue->immediate.routine = NULL;

        queue->immediate.data = NULL;

        queue->malloced = 0;

}

/* Create an initialized sctp_inq.  */

struct sctp_inq *sctp_inq_new(void)

{

        struct sctp_inq *retval;

        retval = t_new(struct sctp_inq, GFP_ATOMIC);

        if (retval) {

                sctp_inq_init(retval);

                retval->malloced = 1;

        }

        return retval;

}

/* Release the memory associated with an SCTP inqueue.  */

void sctp_inq_free(struct sctp_inq *queue)

{

        struct sctp_chunk *chunk;

        /* Empty the queue.  */

        while ((chunk = (struct sctp_chunk *) skb_dequeue(&queue->in)))

                sctp_chunk_free(chunk);

        /* If there is a packet which is currently being worked on,

         * free it as well.

         */

        if (queue->in_progress)

                sctp_chunk_free(queue->in_progress);

        if (queue->malloced) {

                /* Dump the master memory segment.  */

                kfree(queue);

        }

}

/* Put a new packet in an SCTP inqueue.

 * We assume that packet->sctp_hdr is set and in host byte order.

 */

void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *packet)

{

        /* Directly call the packet handling routine. */

        /* We are now calling this either from the soft interrupt

         * or from the backlog processing.

         * Eventually, we should clean up inqueue to not rely

         * on the BH related data structures.

         */

        skb_queue_tail(&(q->in), (struct sk_buff *) packet);

        q->immediate.routine(q->immediate.data);

}

/* Extract a chunk from an SCTP inqueue.

 *

 * WARNING:  If you need to put the chunk on another queue, you need to

 * make a shallow copy (clone) of it.

 */

struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)

{

        struct sctp_chunk *chunk;

        sctp_chunkhdr_t *ch = NULL;

        /* The assumption is that we are safe to process the chunks

         * at this time.

         */

        if ((chunk = queue->in_progress)) {

                /* There is a packet that we have been working on.

                 * Any post processing work to do before we move on?

                 */

                if (chunk->singleton ||

                    chunk->end_of_packet ||

                    chunk->pdiscard) {

                        sctp_chunk_free(chunk);

                        chunk = queue->in_progress = NULL;

                } else {

                        /* Nothing to do. Next chunk in the packet, please. */

                        ch = (sctp_chunkhdr_t *) chunk->chunk_end;

                        /* Force chunk->skb->data to chunk->chunk_end.  */

                        skb_pull(chunk->skb,

                                 chunk->chunk_end - chunk->skb->data);

                }

        }

        /* Do we need to take the next packet out of the queue to process? */

        if (!chunk) {

                /* Is the queue empty?  */

                if (skb_queue_empty(&queue->in))

                        return NULL;

                chunk = queue->in_progress =

                        (struct sctp_chunk *) skb_dequeue(&queue->in);

                /* This is the first chunk in the packet.  */

                chunk->singleton = 1;

                ch = (sctp_chunkhdr_t *) chunk->skb->data;

        }

        chunk->chunk_hdr = ch;

        chunk->chunk_end = ((__u8 *) ch)

                + WORD_ROUND(ntohs(ch->length));

        skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));

        chunk->subh.v = NULL; /* Subheader is no longer valid.  */

        if (chunk->chunk_end < chunk->skb->tail) {

                /* This is not a singleton */

                chunk->singleton = 0;

        } else {

                /* We are at the end of the packet, so mark the chunk

                 * in case we need to send a SACK.

                 */

                chunk->end_of_packet = 1;

        }

        SCTP_DEBUG_PRINTK("+++sctp_inq_pop+++ chunk %p[%s],"

                          " length %d, skb->len %d\n",chunk,

                          sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),

                          ntohs(chunk->chunk_hdr->length), chunk->skb->len);

        return chunk;

}

/* Set a top-half handler.

 *

 * Originally, we the top-half handler was scheduled as a BH.  We now

 * call the handler directly in sctp_inq_push() at a time that

 * we know we are lock safe.

 * The intent is that this routine will pull stuff out of the

 * inqueue and process it.

 */

void sctp_inq_set_th_handler(struct sctp_inq *q,

                                 void (*callback)(void *), void *arg)

{

        q->immediate.routine = callback;

        q->immediate.data = arg;

}