inqueue.c
/* SCTP kernel 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 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.
*
* 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 <linux-sctp@vger.kernel.org>
*
* Written or modified by:
* La Monte H.P. Yarroll <piggy@acm.org>
* Karl Knutson <karl@athena.chicago.il.us>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
/* Initialize an SCTP inqueue. */
void sctp_inq_init(struct sctp_inq *queue)
{
INIT_LIST_HEAD(&queue->in_chunk_list);
queue->in_progress = NULL;
/* Create a task for delivering data. */
INIT_WORK(&queue->immediate, NULL);
}
/* Release the memory associated with an SCTP inqueue. */
void sctp_inq_free(struct sctp_inq *queue)
{
struct sctp_chunk *chunk, *tmp;
/* Empty the queue. */
list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) {
list_del_init(&chunk->list);
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);
queue->in_progress = NULL;
}
}
/* 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 *chunk)
{
/* Directly call the packet handling routine. */
if (chunk->rcvr->dead) {
sctp_chunk_free(chunk);
return;
}
/* 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.
*/
list_add_tail(&chunk->list, &q->in_chunk_list);
if (chunk->asoc)
chunk->asoc->stats.ipackets++;
q->immediate.func(&q->immediate);
}
/* Peek at the next chunk on the inqeue. */
struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue)
{
struct sctp_chunk *chunk;
sctp_chunkhdr_t *ch = NULL;
chunk = queue->in_progress;
/* If there is no more chunks in this packet, say so */
if (chunk->singleton ||
chunk->end_of_packet ||
chunk->pdiscard)
return NULL;
ch = (sctp_chunkhdr_t *)chunk->chunk_end;
return ch;
}
/* 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);
/* Verify that we have at least chunk headers
* worth of buffer left.
*/
if (skb_headlen(chunk->skb) < sizeof(sctp_chunkhdr_t)) {
sctp_chunk_free(chunk);
chunk = queue->in_progress = NULL;
}
}
}
/* Do we need to take the next packet out of the queue to process? */
if (!chunk) {
struct list_head *entry;
/* Is the queue empty? */
if (list_empty(&queue->in_chunk_list))
return NULL;
entry = queue->in_chunk_list.next;
chunk = queue->in_progress =
list_entry(entry, struct sctp_chunk, list);
list_del_init(entry);
/* This is the first chunk in the packet. */
chunk->singleton = 1;
ch = (sctp_chunkhdr_t *) chunk->skb->data;
chunk->data_accepted = 0;
}
chunk->chunk_hdr = ch;
chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
/* In the unlikely case of an IP reassembly, the skb could be
* non-linear. If so, update chunk_end so that it doesn't go past
* the skb->tail.
*/
if (unlikely(skb_is_nonlinear(chunk->skb))) {
if (chunk->chunk_end > skb_tail_pointer(chunk->skb))
chunk->chunk_end = skb_tail_pointer(chunk->skb);
}
skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
chunk->subh.v = NULL; /* Subheader is no longer valid. */
if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) {
/* This is not a singleton */
chunk->singleton = 0;
} else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
/* RFC 2960, Section 6.10 Bundling
*
* Partial chunks MUST NOT be placed in an SCTP packet.
* If the receiver detects a partial chunk, it MUST drop
* the chunk.
*
* Since the end of the chunk is past the end of our buffer
* (which contains the whole packet, we can freely discard
* the whole packet.
*/
sctp_chunk_free(chunk);
chunk = queue->in_progress = NULL;
return NULL;
} 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;
}
pr_debug("+++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, work_func_t callback)
{
INIT_WORK(&q->immediate, callback);
}
