// SPDX-License-Identifier: GPL-2.0-or-later
/* 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.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <[email protected]>
*
* Written or modified by:
* La Monte H.P. Yarroll <[email protected]>
* Karl Knutson <[email protected]>
*/
#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);
}
/* Properly release the chunk which is being worked on. */
static inline void sctp_inq_chunk_free(struct sctp_chunk *chunk)
{
if (chunk->head_skb)
chunk->skb = chunk->head_skb;
sctp_chunk_free(chunk);
}
/* 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_inq_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;
struct sctp_chunkhdr *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 = (struct sctp_chunkhdr *)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;
struct sctp_chunkhdr *ch = NULL;
/* The assumption is that we are safe to process the chunks
* at this time.
*/
chunk = queue->in_progress;
if (chunk) {
/* 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) {
if (chunk->head_skb == chunk->skb) {
chunk->skb = skb_shinfo(chunk->skb)->frag_list;
goto new_skb;
}
if (chunk->skb->next) {
chunk->skb = chunk->skb->next;
goto new_skb;
}
sctp_inq_chunk_free(chunk);
chunk = queue->in_progress = NULL;
} else {
/* Nothing to do. Next chunk in the packet, please. */
ch = (struct sctp_chunkhdr *)chunk->chunk_end;
/* Force chunk->skb->data to chunk->chunk_end. */
skb_pull(chunk->skb, chunk->chunk_end - chunk->skb->data);
/* We are guaranteed to pull a SCTP header. */
}
}
/* Do we need to take the next packet out of the queue to process? */
if (!chunk) {
struct list_head *entry;
next_chunk:
/* Is the queue empty? */
entry = sctp_list_dequeue(&queue->in_chunk_list);
if (!entry)
return NULL;
chunk = list_entry(entry, struct sctp_chunk, list);
if (skb_is_gso(chunk->skb) && skb_is_gso_sctp(chunk->skb)) {
/* GSO-marked skbs but without frags, handle
* them normally
*/
if (skb_shinfo(chunk->skb)->frag_list)
chunk->head_skb = chunk->skb;
/* skbs with "cover letter" */
if (chunk->head_skb && chunk->skb->data_len == chunk->skb->len)
chunk->skb = skb_shinfo(chunk->skb)->frag_list;
if (WARN_ON(!chunk->skb)) {
__SCTP_INC_STATS(dev_net(chunk->skb->dev), SCTP_MIB_IN_PKT_DISCARDS);
sctp_chunk_free(chunk);
goto next_chunk;
}
}
if (chunk->asoc)
sock_rps_save_rxhash(chunk->asoc->base.sk, chunk->skb);
queue->in_progress = chunk;
new_skb:
/* This is the first chunk in the packet. */
ch = (struct sctp_chunkhdr *)chunk->skb->data;
chunk->singleton = 1;
chunk->data_accepted = 0;
chunk->pdiscard = 0;
chunk->auth = 0;
chunk->has_asconf = 0;
chunk->end_of_packet = 0;
if (chunk->head_skb) {
struct sctp_input_cb
*cb = SCTP_INPUT_CB(chunk->skb),
*head_cb = SCTP_INPUT_CB(chunk->head_skb);
cb->chunk = head_cb->chunk;
cb->af = head_cb->af;
}
}
chunk->chunk_hdr = ch;
chunk->chunk_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
skb_pull(chunk->skb, sizeof(*ch));
chunk->subh.v = NULL; /* Subheader is no longer valid. */
if (chunk->chunk_end + sizeof(*ch) <= skb_tail_pointer(chunk->skb)) {
/* This is not a singleton */
chunk->singleton = 0;
} else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
/* Discard inside state machine. */
chunk->pdiscard = 1;
chunk->chunk_end = skb_tail_pointer(chunk->skb);
} 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);
}
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