1 files changed, 237 insertions, 0 deletions
diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
new file mode 100644
index 0000000000..7182c5a450
--- /dev/null
+++ b/net/sctp/inqueue.c
@@ -0,0 +1,237 @@
+// 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 <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;
+	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;
+			}
+
+			if (chunk->head_skb)
+				chunk->skb = chunk->head_skb;
+			sctp_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);
+}