245 lines
7.0 KiB
C
245 lines
7.0 KiB
C
/* SCTP kernel implementation
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* Copyright (c) 1999-2000 Cisco, Inc.
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* Copyright (c) 1999-2001 Motorola, Inc.
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* Copyright (c) 2002 International Business Machines, Corp.
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*
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* This file is part of the SCTP kernel implementation
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*
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* These functions are the methods for accessing the SCTP inqueue.
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*
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* An SCTP inqueue is a queue into which you push SCTP packets
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* (which might be bundles or fragments of chunks) and out of which you
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* pop SCTP whole chunks.
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*
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* This SCTP implementation is free software;
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* you can redistribute it and/or modify it under the terms of
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* the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This SCTP implementation is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied
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* ************************
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU CC; see the file COPYING. If not, write to
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* the Free Software Foundation, 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Please send any bug reports or fixes you make to the
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* email address(es):
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* lksctp developers <lksctp-developers@lists.sourceforge.net>
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*
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* Or submit a bug report through the following website:
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* http://www.sf.net/projects/lksctp
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*
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* Written or modified by:
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* La Monte H.P. Yarroll <piggy@acm.org>
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* Karl Knutson <karl@athena.chicago.il.us>
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*
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* Any bugs reported given to us we will try to fix... any fixes shared will
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* be incorporated into the next SCTP release.
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*/
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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#include <linux/interrupt.h>
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#include <linux/slab.h>
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/* Initialize an SCTP inqueue. */
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void sctp_inq_init(struct sctp_inq *queue)
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{
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INIT_LIST_HEAD(&queue->in_chunk_list);
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queue->in_progress = NULL;
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/* Create a task for delivering data. */
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INIT_WORK(&queue->immediate, NULL);
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queue->malloced = 0;
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}
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/* Release the memory associated with an SCTP inqueue. */
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void sctp_inq_free(struct sctp_inq *queue)
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{
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struct sctp_chunk *chunk, *tmp;
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/* Empty the queue. */
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list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) {
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list_del_init(&chunk->list);
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sctp_chunk_free(chunk);
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}
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/* If there is a packet which is currently being worked on,
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* free it as well.
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*/
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if (queue->in_progress) {
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sctp_chunk_free(queue->in_progress);
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queue->in_progress = NULL;
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}
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if (queue->malloced) {
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/* Dump the master memory segment. */
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kfree(queue);
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}
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}
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/* Put a new packet in an SCTP inqueue.
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* We assume that packet->sctp_hdr is set and in host byte order.
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*/
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void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk)
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{
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/* Directly call the packet handling routine. */
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if (chunk->rcvr->dead) {
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sctp_chunk_free(chunk);
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return;
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}
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/* We are now calling this either from the soft interrupt
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* or from the backlog processing.
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* Eventually, we should clean up inqueue to not rely
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* on the BH related data structures.
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*/
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list_add_tail(&chunk->list, &q->in_chunk_list);
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q->immediate.func(&q->immediate);
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}
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/* Peek at the next chunk on the inqeue. */
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struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue)
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{
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struct sctp_chunk *chunk;
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sctp_chunkhdr_t *ch = NULL;
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chunk = queue->in_progress;
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/* If there is no more chunks in this packet, say so */
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if (chunk->singleton ||
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chunk->end_of_packet ||
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chunk->pdiscard)
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return NULL;
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ch = (sctp_chunkhdr_t *)chunk->chunk_end;
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return ch;
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}
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/* Extract a chunk from an SCTP inqueue.
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*
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* WARNING: If you need to put the chunk on another queue, you need to
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* make a shallow copy (clone) of it.
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*/
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struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)
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{
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struct sctp_chunk *chunk;
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sctp_chunkhdr_t *ch = NULL;
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/* The assumption is that we are safe to process the chunks
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* at this time.
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*/
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if ((chunk = queue->in_progress)) {
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/* There is a packet that we have been working on.
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* Any post processing work to do before we move on?
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*/
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if (chunk->singleton ||
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chunk->end_of_packet ||
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chunk->pdiscard) {
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sctp_chunk_free(chunk);
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chunk = queue->in_progress = NULL;
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} else {
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/* Nothing to do. Next chunk in the packet, please. */
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ch = (sctp_chunkhdr_t *) chunk->chunk_end;
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/* Force chunk->skb->data to chunk->chunk_end. */
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skb_pull(chunk->skb,
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chunk->chunk_end - chunk->skb->data);
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/* Verify that we have at least chunk headers
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* worth of buffer left.
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*/
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if (skb_headlen(chunk->skb) < sizeof(sctp_chunkhdr_t)) {
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sctp_chunk_free(chunk);
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chunk = queue->in_progress = NULL;
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}
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}
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}
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/* Do we need to take the next packet out of the queue to process? */
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if (!chunk) {
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struct list_head *entry;
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/* Is the queue empty? */
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if (list_empty(&queue->in_chunk_list))
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return NULL;
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entry = queue->in_chunk_list.next;
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chunk = queue->in_progress =
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list_entry(entry, struct sctp_chunk, list);
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list_del_init(entry);
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/* This is the first chunk in the packet. */
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chunk->singleton = 1;
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ch = (sctp_chunkhdr_t *) chunk->skb->data;
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chunk->data_accepted = 0;
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}
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chunk->chunk_hdr = ch;
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chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
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/* In the unlikely case of an IP reassembly, the skb could be
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* non-linear. If so, update chunk_end so that it doesn't go past
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* the skb->tail.
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*/
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if (unlikely(skb_is_nonlinear(chunk->skb))) {
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if (chunk->chunk_end > skb_tail_pointer(chunk->skb))
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chunk->chunk_end = skb_tail_pointer(chunk->skb);
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}
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skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
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chunk->subh.v = NULL; /* Subheader is no longer valid. */
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if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) {
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/* This is not a singleton */
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chunk->singleton = 0;
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} else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
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/* RFC 2960, Section 6.10 Bundling
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*
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* Partial chunks MUST NOT be placed in an SCTP packet.
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* If the receiver detects a partial chunk, it MUST drop
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* the chunk.
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*
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* Since the end of the chunk is past the end of our buffer
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* (which contains the whole packet, we can freely discard
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* the whole packet.
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*/
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sctp_chunk_free(chunk);
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chunk = queue->in_progress = NULL;
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return NULL;
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} else {
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/* We are at the end of the packet, so mark the chunk
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* in case we need to send a SACK.
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*/
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chunk->end_of_packet = 1;
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}
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SCTP_DEBUG_PRINTK("+++sctp_inq_pop+++ chunk %p[%s],"
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" length %d, skb->len %d\n",chunk,
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sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),
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ntohs(chunk->chunk_hdr->length), chunk->skb->len);
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return chunk;
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}
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/* Set a top-half handler.
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*
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* Originally, we the top-half handler was scheduled as a BH. We now
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* call the handler directly in sctp_inq_push() at a time that
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* we know we are lock safe.
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* The intent is that this routine will pull stuff out of the
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* inqueue and process it.
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*/
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void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback)
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{
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INIT_WORK(&q->immediate, callback);
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}
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