1 files changed, 364 insertions, 0 deletions

diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
new file mode 100644
index 00000000..6c855645
--- /dev/null
+++ b/net/sctp/chunk.c
@@ -0,0 +1,364 @@
+/* SCTP kernel implementation
+ * (C) Copyright IBM Corp. 2003, 2004
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * This file contains the code relating the chunk abstraction.
+ *
+ * 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 <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>
+ *    Sridhar Samudrala     <sri@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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/net.h>
+#include <linux/inet.h>
+#include <linux/skbuff.h>
+#include <linux/slab.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. */
+static void sctp_datamsg_init(struct sctp_datamsg *msg)
+{
+	atomic_set(&msg->refcnt, 1);
+	msg->send_failed = 0;
+	msg->send_error = 0;
+	msg->can_abandon = 0;
+	msg->can_delay = 1;
+	msg->expires_at = 0;
+	INIT_LIST_HEAD(&msg->chunks);
+}
+
+/* Allocate and initialize datamsg. */
+SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t 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;
+}
+
+void sctp_datamsg_free(struct sctp_datamsg *msg)
+{
+	struct sctp_chunk *chunk;
+
+	/* This doesn't have to be a _safe vairant because
+	 * sctp_chunk_free() only drops the refs.
+	 */
+	list_for_each_entry(chunk, &msg->chunks, frag_list)
+		sctp_chunk_free(chunk);
+
+	sctp_datamsg_put(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_sock *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. */
+static 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);
+}
+
+/* Assign a chunk to this datamsg. */
+static 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;
+	int max_data;
+	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 +
+				    msecs_to_jiffies(sinfo->sinfo_timetolive);
+		msg->can_abandon = 1;
+		SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n",
+				  __func__, msg, msg->expires_at, jiffies);
+	}
+
+	/* This is the biggest possible DATA chunk that can fit into
+	 * the packet
+	 */
+	max_data = asoc->pathmtu -
+		sctp_sk(asoc->base.sk)->pf->af->net_header_len -
+		sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk);
+
+	max = asoc->frag_point;
+	/* If the the peer requested that we authenticate DATA chunks
+	 * we need to accound for bundling of the AUTH chunks along with
+	 * DATA.
+	 */
+	if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
+		struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
+
+		if (hmac_desc)
+			max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
+					    hmac_desc->hmac_len);
+	}
+
+	/* Now, check if we need to reduce our max */
+	if (max > max_data)
+		max = max_data;
+
+	whole = 0;
+	first_len = max;
+
+	/* Check to see if we have a pending SACK and try to let it be bundled
+	 * with this message.  Do this if we don't have any data queued already.
+	 * To check that, look at out_qlen and retransmit list.
+	 * NOTE: we will not reduce to account for SACK, if the message would
+	 * not have been fragmented.
+	 */
+	if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) &&
+	    asoc->outqueue.out_qlen == 0 &&
+	    list_empty(&asoc->outqueue.retransmit) &&
+	    msg_len > max)
+		max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t));
+
+	/* Encourage Cookie-ECHO bundling. */
+	if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
+		max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
+
+	/* Now that we adjusted completely, reset first_len */
+	if (first_len > max_data)
+		first_len = max_data;
+
+	/* Account for a different sized first fragment */
+	if (msg_len >= first_len) {
+		msg_len -= first_len;
+		whole = 1;
+		msg->can_delay = 0;
+	}
+
+	/* 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(SCTP_MIB_FRAGUSRMSGS);
+
+	/* 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;
+
+			/* The application requests to set the I-bit of the
+			 * last DATA chunk of a user message when providing
+			 * the user message to the SCTP implementation.
+			 */
+			if ((sinfo->sinfo_flags & SCTP_EOF) ||
+			    (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
+				frag |= SCTP_DATA_SACK_IMM;
+		}
+
+		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;
+
+		if ((sinfo->sinfo_flags & SCTP_EOF) ||
+		    (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
+			frag |= SCTP_DATA_SACK_IMM;
+
+		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_put(msg);
+	return NULL;
+}
+
+/* Check whether this message has expired. */
+int sctp_chunk_abandoned(struct sctp_chunk *chunk)
+{
+	struct sctp_datamsg *msg = chunk->msg;
+
+	if (!msg->can_abandon)
+		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_chunk_fail(struct sctp_chunk *chunk, int error)
+{
+	chunk->msg->send_failed = 1;
+	chunk->msg->send_error = error;
+}