patch-2.4.26 linux-2.4.26/net/sctp/chunk.c

• Lines: 324
• Date: 2004-04-14 06:05:41.000000000 -0700
• Orig file: linux-2.4.25/net/sctp/chunk.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.25/net/sctp/chunk.c linux-2.4.26/net/sctp/chunk.c
@@ -0,0 +1,323 @@
+/* SCTP kernel reference Implementation
+ * Copyright (c) 2003 International Business Machines Corp.
+ *
+ * This file is part of the SCTP kernel reference Implementation
+ *
+ * This file contains the code relating the the chunk abstraction.
+ *
+ * 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:
+ *    Jon Grimm             <jgrimm@us.ibm.com>
+ *
+ * Any bugs reported given to us we will try to fix... any fixes shared will
+ * be incorporated into the next SCTP release.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/net.h>
+#include <linux/inet.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+
+/* This file is mostly in anticipation of future work, but initially
+ * populate with fragment tracking for an outbound message.
+ */
+
+/* Initialize datamsg from memory. */
+void sctp_datamsg_init(struct sctp_datamsg *msg)
+{
+	atomic_set(&msg->refcnt, 1);
+	msg->send_failed = 0;
+	msg->send_error = 0;
+	msg->can_expire = 0;
+	INIT_LIST_HEAD(&msg->chunks);
+}
+
+/* Allocate and initialize datamsg. */
+struct sctp_datamsg *sctp_datamsg_new(int gfp)
+{
+	struct sctp_datamsg *msg;
+	msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
+	if (msg)
+		sctp_datamsg_init(msg);
+	SCTP_DBG_OBJCNT_INC(datamsg);
+	return msg;
+}
+
+/* Final destructruction of datamsg memory. */
+static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
+{
+	struct list_head *pos, *temp;
+	struct sctp_chunk *chunk;
+	struct sctp_opt *sp;
+	struct sctp_ulpevent *ev;
+	struct sctp_association *asoc = NULL;
+	int error = 0, notify;
+
+	/* If we failed, we may need to notify. */
+	notify = msg->send_failed ? -1 : 0;
+
+	/* Release all references. */
+	list_for_each_safe(pos, temp, &msg->chunks) {
+		list_del_init(pos);
+		chunk = list_entry(pos, struct sctp_chunk, frag_list);
+		/* Check whether we _really_ need to notify. */
+		if (notify < 0) {
+			asoc = chunk->asoc;
+			if (msg->send_error)
+				error = msg->send_error;
+			else
+				error = asoc->outqueue.error;
+
+			sp = sctp_sk(asoc->base.sk);
+			notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
+							    &sp->subscribe);
+		}
+
+		/* Generate a SEND FAILED event only if enabled. */
+		if (notify > 0) {
+			int sent;
+			if (chunk->has_tsn)
+				sent = SCTP_DATA_SENT;
+			else
+				sent = SCTP_DATA_UNSENT;
+
+			ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
+							    error, GFP_ATOMIC);
+			if (ev)
+				sctp_ulpq_tail_event(&asoc->ulpq, ev);
+		}
+
+		sctp_chunk_put(chunk);
+	}
+
+	SCTP_DBG_OBJCNT_DEC(datamsg);
+	kfree(msg);
+}
+
+/* Hold a reference. */
+void sctp_datamsg_hold(struct sctp_datamsg *msg)
+{
+	atomic_inc(&msg->refcnt);
+}
+
+/* Release a reference. */
+void sctp_datamsg_put(struct sctp_datamsg *msg)
+{
+	if (atomic_dec_and_test(&msg->refcnt))
+		sctp_datamsg_destroy(msg);
+}
+
+/* Free a message.  Really just give up a reference, the
+ * really free happens in sctp_datamsg_destroy().
+ */
+void sctp_datamsg_free(struct sctp_datamsg *msg)
+{
+	sctp_datamsg_put(msg);
+}
+
+/* Hold on to all the fragments until all chunks have been sent. */
+void sctp_datamsg_track(struct sctp_chunk *chunk)
+{
+	sctp_chunk_hold(chunk);
+}
+
+/* Assign a chunk to this datamsg. */
+void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
+{
+	sctp_datamsg_hold(msg);
+	chunk->msg = msg;
+}
+
+
+/* A data chunk can have a maximum payload of (2^16 - 20).  Break
+ * down any such message into smaller chunks.  Opportunistically, fragment
+ * the chunks down to the current MTU constraints.  We may get refragmented
+ * later if the PMTU changes, but it is _much better_ to fragment immediately
+ * with a reasonable guess than always doing our fragmentation on the
+ * soft-interrupt.
+ */
+struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
+					    struct sctp_sndrcvinfo *sinfo,
+					    struct msghdr *msgh, int msg_len)
+{
+	int max, whole, i, offset, over, err;
+	int len, first_len;
+	struct sctp_chunk *chunk;
+	struct sctp_datamsg *msg;
+	struct list_head *pos, *temp;
+	__u8 frag;
+
+	msg = sctp_datamsg_new(GFP_KERNEL);
+	if (!msg)
+		return NULL;
+
+	/* Note: Calculate this outside of the loop, so that all fragments
+	 * have the same expiration.
+	 */
+	if (sinfo->sinfo_timetolive) {
+		/* sinfo_timetolive is in milliseconds */
+		msg->expires_at = jiffies +
+				     SCTP_MSECS_TO_JIFFIES(sinfo->sinfo_timetolive);
+		msg->can_expire = 1;
+	}
+
+	/* What is a reasonable fragmentation point right now? */
+	max = asoc->pmtu;
+	if (max < SCTP_MIN_PMTU)
+		max = SCTP_MIN_PMTU;
+	max -= SCTP_IP_OVERHEAD;
+
+	/* Make sure not beyond maximum chunk size. */
+	if (max > SCTP_MAX_CHUNK_LEN)
+		max = SCTP_MAX_CHUNK_LEN;
+
+	/* Subtract out the overhead of a data chunk header. */
+	max -= sizeof(struct sctp_data_chunk);
+	whole = 0;
+
+	/* If user has specified smaller fragmentation, make it so. */
+	if (sctp_sk(asoc->base.sk)->user_frag)
+		max = min_t(int, max, sctp_sk(asoc->base.sk)->user_frag);
+
+	first_len = max;
+
+	/* Encourage Cookie-ECHO bundling. */
+	if (asoc->state < SCTP_STATE_COOKIE_ECHOED) {
+		whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN);
+
+		/* Account for the DATA to be bundled with the COOKIE-ECHO. */
+		if (whole) {
+			first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN;
+			msg_len -= first_len;
+			whole = 1;
+		}
+	}
+
+	/* How many full sized?  How many bytes leftover? */
+	whole += msg_len / max;
+	over = msg_len % max;
+	offset = 0;
+
+	if ((whole > 1) || (whole && over))
+		SCTP_INC_STATS_USER(SctpFragUsrMsgs);
+
+	/* Create chunks for all the full sized DATA chunks. */
+	for (i=0, len=first_len; i < whole; i++) {
+		frag = SCTP_DATA_MIDDLE_FRAG;
+
+		if (0 == i)
+			frag |= SCTP_DATA_FIRST_FRAG;
+
+		if ((i == (whole - 1)) && !over)
+			frag |= SCTP_DATA_LAST_FRAG;
+
+		chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
+
+		if (!chunk)
+			goto errout;
+		err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
+		if (err < 0)
+			goto errout;
+
+		offset += len;
+
+		/* Put the chunk->skb back into the form expected by send.  */
+		__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
+			   - (__u8 *)chunk->skb->data);
+
+		sctp_datamsg_assign(msg, chunk);
+		list_add_tail(&chunk->frag_list, &msg->chunks);
+
+		/* The first chunk, the first chunk was likely short
+		 * to allow bundling, so reset to full size.
+		 */
+		if (0 == i)
+			len = max;
+	}
+
+	/* .. now the leftover bytes. */
+	if (over) {
+		if (!whole)
+			frag = SCTP_DATA_NOT_FRAG;
+		else
+			frag = SCTP_DATA_LAST_FRAG;
+
+		chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
+
+		if (!chunk)
+			goto errout;
+
+		err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov);
+
+		/* Put the chunk->skb back into the form expected by send.  */
+		__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
+			   - (__u8 *)chunk->skb->data);
+		if (err < 0)
+			goto errout;
+
+		sctp_datamsg_assign(msg, chunk);
+		list_add_tail(&chunk->frag_list, &msg->chunks);
+	}
+
+	return msg;
+
+errout:
+	list_for_each_safe(pos, temp, &msg->chunks) {
+		list_del_init(pos);
+		chunk = list_entry(pos, struct sctp_chunk, frag_list);
+		sctp_chunk_free(chunk);
+	}
+	sctp_datamsg_free(msg);
+	return NULL;
+}
+
+/* Check whether this message has expired. */
+int sctp_datamsg_expires(struct sctp_chunk *chunk)
+{
+	struct sctp_datamsg *msg = chunk->msg;
+
+	/* FIXME: When PR-SCTP is supported we can make this
+	 * check more lenient.
+	 */
+	if (!msg->can_expire)
+		return 0;
+
+	if (time_after(jiffies, msg->expires_at))
+		return 1;
+
+	return 0;
+}
+
+/* This chunk (and consequently entire message) has failed in its sending. */
+void sctp_datamsg_fail(struct sctp_chunk *chunk, int error)
+{
+	chunk->msg->send_failed = 1;
+	chunk->msg->send_error = error;
+}