patch-2.4.23 linux-2.4.23/net/sctp/ulpevent.c

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diff -urN linux-2.4.22/net/sctp/ulpevent.c linux-2.4.23/net/sctp/ulpevent.c
@@ -0,0 +1,883 @@
+/* SCTP kernel reference Implementation
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001 International Business Machines, Corp.
+ * Copyright (c) 2001 Intel Corp.
+ * Copyright (c) 2001 Nokia, Inc.
+ * Copyright (c) 2001 La Monte H.P. Yarroll
+ *
+ * These functions manipulate an sctp event.   The struct ulpevent is used
+ * to carry notifications and data to the ULP (sockets).
+ * 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>
+ *    La Monte H.P. Yarroll <piggy@acm.org>
+ *
+ * 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/skbuff.h>
+#include <net/sctp/structs.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+
+static void sctp_ulpevent_set_owner_r(struct sk_buff *skb,
+				      struct sctp_association *asoc);
+static void sctp_ulpevent_set_owner(struct sk_buff *skb,
+				    const struct sctp_association *asoc);
+
+/* Create a new sctp_ulpevent.  */
+struct sctp_ulpevent *sctp_ulpevent_new(int size, int msg_flags, int gfp)
+{
+	struct sctp_ulpevent *event;
+	struct sk_buff *skb;
+
+	skb = alloc_skb(size, gfp);
+	if (!skb)
+		goto fail;
+
+	event = sctp_skb2event(skb);
+	event = sctp_ulpevent_init(event, msg_flags);
+	if (!event)
+		goto fail_init;
+	return event;
+
+fail_init:
+	kfree_skb(skb);
+fail:
+	return NULL;
+}
+
+/* Initialize an ULP event from an given skb.  */
+struct sctp_ulpevent *sctp_ulpevent_init(struct sctp_ulpevent *event,
+					 int msg_flags)
+{
+	memset(event, sizeof(struct sctp_ulpevent), 0x00);
+	event->msg_flags = msg_flags;
+	return event;
+}
+
+/* Dispose of an event.  */
+void sctp_ulpevent_free(struct sctp_ulpevent *event)
+{
+	kfree_skb(sctp_event2skb(event));
+}
+
+/* Is this a MSG_NOTIFICATION?  */
+int sctp_ulpevent_is_notification(const struct sctp_ulpevent *event)
+{
+	return MSG_NOTIFICATION == (event->msg_flags & MSG_NOTIFICATION);
+}
+
+/* Create and initialize an SCTP_ASSOC_CHANGE event.
+ *
+ * 5.3.1.1 SCTP_ASSOC_CHANGE
+ *
+ * Communication notifications inform the ULP that an SCTP association
+ * has either begun or ended. The identifier for a new association is
+ * provided by this notification.
+ *
+ * Note: There is no field checking here.  If a field is unused it will be
+ * zero'd out.
+ */
+struct sctp_ulpevent  *sctp_ulpevent_make_assoc_change(
+	const struct sctp_association *asoc,
+	__u16 flags, __u16 state, __u16 error, __u16 outbound,
+	__u16 inbound, int gfp)
+{
+	struct sctp_ulpevent *event;
+	struct sctp_assoc_change *sac;
+	struct sk_buff *skb;
+
+	event = sctp_ulpevent_new(sizeof(struct sctp_assoc_change),
+				  MSG_NOTIFICATION, gfp);
+	if (!event)
+		goto fail;
+	skb = sctp_event2skb(event);
+	sac = (struct sctp_assoc_change *)
+		skb_put(skb, sizeof(struct sctp_assoc_change));
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.1 SCTP_ASSOC_CHANGE
+	 *
+	 * sac_type:
+	 * It should be SCTP_ASSOC_CHANGE.
+	 */
+	sac->sac_type = SCTP_ASSOC_CHANGE;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.1 SCTP_ASSOC_CHANGE
+	 *
+	 * sac_state: 32 bits (signed integer)
+	 * This field holds one of a number of values that communicate the
+	 * event that happened to the association.
+	 */
+	sac->sac_state = state;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.1 SCTP_ASSOC_CHANGE
+	 *
+	 * sac_flags: 16 bits (unsigned integer)
+	 * Currently unused.
+	 */
+	sac->sac_flags = 0;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.1 SCTP_ASSOC_CHANGE
+	 *
+	 * sac_length: sizeof (__u32)
+	 * This field is the total length of the notification data, including
+	 * the notification header.
+	 */
+	sac->sac_length = sizeof(struct sctp_assoc_change);
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.1 SCTP_ASSOC_CHANGE
+	 *
+	 * sac_error:  32 bits (signed integer)
+	 *
+	 * If the state was reached due to a error condition (e.g.
+	 * COMMUNICATION_LOST) any relevant error information is available in
+	 * this field. This corresponds to the protocol error codes defined in
+	 * [SCTP].
+	 */
+	sac->sac_error = error;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.1 SCTP_ASSOC_CHANGE
+	 *
+	 * sac_outbound_streams:  16 bits (unsigned integer)
+	 * sac_inbound_streams:  16 bits (unsigned integer)
+	 *
+	 * The maximum number of streams allowed in each direction are
+	 * available in sac_outbound_streams and sac_inbound streams.
+	 */
+	sac->sac_outbound_streams = outbound;
+	sac->sac_inbound_streams = inbound;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.1 SCTP_ASSOC_CHANGE
+	 *
+	 * sac_assoc_id: sizeof (sctp_assoc_t)
+	 *
+	 * The association id field, holds the identifier for the association.
+	 * All notifications for a given association have the same association
+	 * identifier.  For TCP style socket, this field is ignored.
+	 */
+	sctp_ulpevent_set_owner(skb, asoc);
+	sac->sac_assoc_id = sctp_assoc2id(asoc);
+
+	return event;
+
+fail:
+	return NULL;
+}
+
+/* Create and initialize an SCTP_PEER_ADDR_CHANGE event.
+ *
+ * Socket Extensions for SCTP - draft-01
+ * 5.3.1.2 SCTP_PEER_ADDR_CHANGE
+ *
+ * When a destination address on a multi-homed peer encounters a change
+ * an interface details event is sent.
+ */
+struct sctp_ulpevent *sctp_ulpevent_make_peer_addr_change(
+	const struct sctp_association *asoc,
+	const struct sockaddr_storage *aaddr,
+	int flags, int state, int error, int gfp)
+{
+	struct sctp_ulpevent *event;
+	struct sctp_paddr_change  *spc;
+	struct sk_buff *skb;
+
+	event = sctp_ulpevent_new(sizeof(struct sctp_paddr_change),
+				  MSG_NOTIFICATION, gfp);
+	if (!event)
+		goto fail;
+
+	skb = sctp_event2skb(event);
+	spc = (struct sctp_paddr_change *)
+		skb_put(skb, sizeof(struct sctp_paddr_change));
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
+	 *
+	 * spc_type:
+	 *
+	 *    It should be SCTP_PEER_ADDR_CHANGE.
+	 */
+	spc->spc_type = SCTP_PEER_ADDR_CHANGE;
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
+	 *
+	 * spc_length: sizeof (__u32)
+	 *
+	 * This field is the total length of the notification data, including
+	 * the notification header.
+	 */
+	spc->spc_length = sizeof(struct sctp_paddr_change);
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
+	 *
+	 * spc_flags: 16 bits (unsigned integer)
+	 * Currently unused.
+	 */
+	spc->spc_flags = 0;
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
+	 *
+	 * spc_state:  32 bits (signed integer)
+	 *
+	 * This field holds one of a number of values that communicate the
+	 * event that happened to the address.
+	 */
+	spc->spc_state = state;
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
+	 *
+	 * spc_error:  32 bits (signed integer)
+	 *
+	 * If the state was reached due to any error condition (e.g.
+	 * ADDRESS_UNREACHABLE) any relevant error information is available in
+	 * this field.
+	 */
+	spc->spc_error = error;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.1 SCTP_ASSOC_CHANGE
+	 *
+	 * spc_assoc_id: sizeof (sctp_assoc_t)
+	 *
+	 * The association id field, holds the identifier for the association.
+	 * All notifications for a given association have the same association
+	 * identifier.  For TCP style socket, this field is ignored.
+	 */
+	sctp_ulpevent_set_owner(skb, asoc);
+	spc->spc_assoc_id = sctp_assoc2id(asoc);
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
+	 *
+	 * spc_aaddr: sizeof (struct sockaddr_storage)
+	 *
+	 * The affected address field, holds the remote peer's address that is
+	 * encountering the change of state.
+	 */
+	memcpy(&spc->spc_aaddr, aaddr, sizeof(struct sockaddr_storage));
+
+	return event;
+
+fail:
+	return NULL;
+}
+
+/* Create and initialize an SCTP_REMOTE_ERROR notification.
+ *
+ * Note: This assumes that the chunk->skb->data already points to the
+ * operation error payload.
+ *
+ * Socket Extensions for SCTP - draft-01
+ * 5.3.1.3 SCTP_REMOTE_ERROR
+ *
+ * A remote peer may send an Operational Error message to its peer.
+ * This message indicates a variety of error conditions on an
+ * association. The entire error TLV as it appears on the wire is
+ * included in a SCTP_REMOTE_ERROR event.  Please refer to the SCTP
+ * specification [SCTP] and any extensions for a list of possible
+ * error formats.
+ */
+struct sctp_ulpevent *sctp_ulpevent_make_remote_error(
+	const struct sctp_association *asoc, sctp_chunk_t *chunk,
+	__u16 flags, int gfp)
+{
+	struct sctp_ulpevent *event;
+	struct sctp_remote_error *sre;
+	struct sk_buff *skb;
+	sctp_errhdr_t *ch;
+	__u16 cause;
+	int elen;
+
+	ch = (sctp_errhdr_t *)(chunk->skb->data);
+	cause = ch->cause;
+	elen = ntohs(ch->length) - sizeof(sctp_errhdr_t);
+
+	/* Pull off the ERROR header.  */
+	skb_pull(chunk->skb, sizeof(sctp_errhdr_t));
+
+	/* Copy the skb to a new skb with room for us to prepend
+	 * notification with.
+	 */
+	skb = skb_copy_expand(chunk->skb,
+			      sizeof(struct sctp_remote_error), /* headroom */
+			      0,                                /* tailroom */
+			      gfp);
+
+	/* Pull off the rest of the cause TLV from the chunk.  */
+	skb_pull(chunk->skb, elen);
+	if (!skb)
+		goto fail;
+
+	/* Embed the event fields inside the cloned skb.  */
+	event = sctp_skb2event(skb);
+	event = sctp_ulpevent_init(event, MSG_NOTIFICATION);
+
+	if (!event)
+		goto fail;
+
+	sre = (struct sctp_remote_error *)
+		skb_push(skb, sizeof(struct sctp_remote_error));
+
+	/* Trim the buffer to the right length.  */
+	skb_trim(skb, sizeof(struct sctp_remote_error) + elen);
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.3 SCTP_REMOTE_ERROR
+	 *
+	 * sre_type:
+	 *   It should be SCTP_REMOTE_ERROR.
+	 */
+	sre->sre_type = SCTP_REMOTE_ERROR;
+
+	/*
+	 * Socket Extensions for SCTP
+	 * 5.3.1.3 SCTP_REMOTE_ERROR
+	 *
+	 * sre_flags: 16 bits (unsigned integer)
+	 *   Currently unused.
+	 */
+	sre->sre_flags = 0;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.3 SCTP_REMOTE_ERROR
+	 *
+	 * sre_length: sizeof (__u32)
+	 *
+	 * This field is the total length of the notification data,
+	 * including the notification header.
+	 */
+	sre->sre_length = skb->len;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.3 SCTP_REMOTE_ERROR
+	 *
+	 * sre_error: 16 bits (unsigned integer)
+	 * This value represents one of the Operational Error causes defined in
+	 * the SCTP specification, in network byte order.
+	 */
+	sre->sre_error = cause;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.3 SCTP_REMOTE_ERROR
+	 *
+	 * sre_assoc_id: sizeof (sctp_assoc_t)
+	 *
+	 * The association id field, holds the identifier for the association.
+	 * All notifications for a given association have the same association
+	 * identifier.  For TCP style socket, this field is ignored.
+	 */
+	skb = sctp_event2skb(event);
+	sctp_ulpevent_set_owner(skb, asoc);
+	sre->sre_assoc_id = sctp_assoc2id(asoc);
+
+	return event;
+
+fail:
+	return NULL;
+}
+
+/* Create and initialize a SCTP_SEND_FAILED notification.
+ *
+ * Socket Extensions for SCTP - draft-01
+ * 5.3.1.4 SCTP_SEND_FAILED
+ */
+struct sctp_ulpevent *sctp_ulpevent_make_send_failed(
+	const struct sctp_association *asoc, sctp_chunk_t *chunk,
+	__u16 flags, __u32 error, int gfp)
+{
+	struct sctp_ulpevent *event;
+	struct sctp_send_failed *ssf;
+	struct sk_buff *skb;
+
+	/* Make skb with more room so we can prepend notification.  */
+	skb = skb_copy_expand(chunk->skb,
+			      sizeof(struct sctp_send_failed), /* headroom */
+			      0,                               /* tailroom */
+			      gfp);
+	if (!skb)
+		goto fail;
+
+	/* Pull off the common chunk header and DATA header.  */
+	skb_pull(skb, sizeof(sctp_data_chunk_t));
+
+	/* Embed the event fields inside the cloned skb.  */
+	event = sctp_skb2event(skb);
+	event = sctp_ulpevent_init(event, MSG_NOTIFICATION);
+	if (!event)
+		goto fail;
+
+	ssf = (struct sctp_send_failed *)
+		skb_push(skb, sizeof(struct sctp_send_failed));
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.4 SCTP_SEND_FAILED
+	 *
+	 * ssf_type:
+	 * It should be SCTP_SEND_FAILED.
+	 */
+	ssf->ssf_type = SCTP_SEND_FAILED;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.4 SCTP_SEND_FAILED
+	 *
+	 * ssf_flags: 16 bits (unsigned integer)
+	 * The flag value will take one of the following values
+	 *
+	 * SCTP_DATA_UNSENT - Indicates that the data was never put on
+	 *                    the wire.
+	 *
+	 * SCTP_DATA_SENT   - Indicates that the data was put on the wire.
+	 *                    Note that this does not necessarily mean that the
+	 *                    data was (or was not) successfully delivered.
+	 */
+	ssf->ssf_flags = flags;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.4 SCTP_SEND_FAILED
+	 *
+	 * ssf_length: sizeof (__u32)
+	 * This field is the total length of the notification data, including
+	 * the notification header.
+	 */
+	ssf->ssf_length = skb->len;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.4 SCTP_SEND_FAILED
+	 *
+	 * ssf_error: 16 bits (unsigned integer)
+	 * This value represents the reason why the send failed, and if set,
+	 * will be a SCTP protocol error code as defined in [SCTP] section
+	 * 3.3.10.
+	 */
+	ssf->ssf_error = error;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.4 SCTP_SEND_FAILED
+	 *
+	 * ssf_info: sizeof (struct sctp_sndrcvinfo)
+	 * The original send information associated with the undelivered
+	 * message.
+	 */
+	memcpy(&ssf->ssf_info, &chunk->sinfo, sizeof(struct sctp_sndrcvinfo));
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.4 SCTP_SEND_FAILED
+	 *
+	 * ssf_assoc_id: sizeof (sctp_assoc_t)
+	 * The association id field, sf_assoc_id, holds the identifier for the
+	 * association.  All notifications for a given association have the
+	 * same association identifier.  For TCP style socket, this field is
+	 * ignored.
+	 */
+	skb = sctp_event2skb(event);
+	sctp_ulpevent_set_owner(skb, asoc);
+	ssf->ssf_assoc_id = sctp_assoc2id(asoc);
+	return event;
+
+fail:
+	return NULL;
+}
+
+/* Create and initialize a SCTP_SHUTDOWN_EVENT notification.
+ *
+ * Socket Extensions for SCTP - draft-01
+ * 5.3.1.5 SCTP_SHUTDOWN_EVENT
+ */
+struct sctp_ulpevent *sctp_ulpevent_make_shutdown_event(
+	const struct sctp_association *asoc,
+	__u16 flags, int gfp)
+{
+	struct sctp_ulpevent *event;
+	struct sctp_shutdown_event *sse;
+	struct sk_buff *skb;
+
+	event = sctp_ulpevent_new(sizeof(struct sctp_assoc_change),
+				  MSG_NOTIFICATION, gfp);
+	if (!event)
+		goto fail;
+
+	skb = sctp_event2skb(event);
+	sse = (struct sctp_shutdown_event *)
+		skb_put(skb, sizeof(struct sctp_shutdown_event));
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
+	 *
+	 * sse_type
+	 * It should be SCTP_SHUTDOWN_EVENT
+	 */
+	sse->sse_type = SCTP_SHUTDOWN_EVENT;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
+	 *
+	 * sse_flags: 16 bits (unsigned integer)
+	 * Currently unused.
+	 */
+	sse->sse_flags = 0;
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
+	 *
+	 * sse_length: sizeof (__u32)
+	 * This field is the total length of the notification data, including
+	 * the notification header.
+	 */
+	sse->sse_length = sizeof(struct sctp_shutdown_event);
+
+	/* Socket Extensions for SCTP
+	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
+	 *
+	 * sse_assoc_id: sizeof (sctp_assoc_t)
+	 * The association id field, holds the identifier for the association.
+	 * All notifications for a given association have the same association
+	 * identifier.  For TCP style socket, this field is ignored.
+	 */
+	sctp_ulpevent_set_owner(skb, asoc);
+	sse->sse_assoc_id = sctp_assoc2id(asoc);
+
+	return event;
+
+fail:
+	return NULL;
+}
+
+/* A message has been received.  Package this message as a notification
+ * to pass it to the upper layers.  Go ahead and calculate the sndrcvinfo
+ * even if filtered out later.
+ *
+ * Socket Extensions for SCTP
+ * 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
+ */
+struct sctp_ulpevent *sctp_ulpevent_make_rcvmsg(struct sctp_association *asoc,
+		   sctp_chunk_t *chunk, int gfp)
+{
+	struct sctp_ulpevent *event;
+	struct sctp_sndrcvinfo *info;
+	struct sk_buff *skb, *list;
+	size_t padding, len;
+
+	/* Clone the original skb, sharing the data.  */
+	skb = skb_clone(chunk->skb, gfp);
+	if (!skb)
+		goto fail;
+
+	/* First calculate the padding, so we don't inadvertently
+	 * pass up the wrong length to the user.
+	 *
+	 * RFC 2960 - Section 3.2  Chunk Field Descriptions
+	 *
+	 * The total length of a chunk(including Type, Length and Value fields)
+	 * MUST be a multiple of 4 bytes.  If the length of the chunk is not a
+	 * multiple of 4 bytes, the sender MUST pad the chunk with all zero
+	 * bytes and this padding is not included in the chunk length field.
+	 * The sender should never pad with more than 3 bytes.  The receiver
+	 * MUST ignore the padding bytes.
+	 */
+	len = ntohs(chunk->chunk_hdr->length);
+	padding = WORD_ROUND(len) - len;
+
+	/* Fixup cloned skb with just this chunks data.  */
+	skb_trim(skb, chunk->chunk_end - padding - skb->data);
+
+	/* Set up a destructor to do rwnd accounting.  */
+	sctp_ulpevent_set_owner_r(skb, asoc);
+
+	/* Embed the event fields inside the cloned skb.  */
+	event = sctp_skb2event(skb);
+
+	/* Initialize event with flags 0.  */
+	event = sctp_ulpevent_init(event, 0);
+	if (!event)
+		goto fail_init;
+
+	event->iif = sctp_chunk_iif(chunk);
+	/* Note:  Not clearing the entire event struct as
+	 * this is just a fragment of the real event.  However,
+	 * we still need to do rwnd accounting.
+	 */
+	for (list = skb_shinfo(skb)->frag_list; list; list = list->next)
+		sctp_ulpevent_set_owner_r(list, asoc);
+
+	info = (struct sctp_sndrcvinfo *) &event->sndrcvinfo;
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
+	 *
+	 * sinfo_stream: 16 bits (unsigned integer)
+	 *
+	 * For recvmsg() the SCTP stack places the message's stream number in
+	 * this value.
+	 */
+	info->sinfo_stream = ntohs(chunk->subh.data_hdr->stream);
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
+	 *
+	 * sinfo_ssn: 16 bits (unsigned integer)
+	 *
+	 * For recvmsg() this value contains the stream sequence number that
+	 * the remote endpoint placed in the DATA chunk.  For fragmented
+	 * messages this is the same number for all deliveries of the message
+	 * (if more than one recvmsg() is needed to read the message).
+	 */
+	info->sinfo_ssn = ntohs(chunk->subh.data_hdr->ssn);
+
+        /* Sockets API Extensions for SCTP
+	 * Section 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
+	 *
+	 * sinfo_ppid: 32 bits (unsigned integer)
+	 *
+	 * In recvmsg() this value is
+	 * the same information that was passed by the upper layer in the peer
+	 * application.  Please note that byte order issues are NOT accounted
+	 * for and this information is passed opaquely by the SCTP stack from
+	 * one end to the other.
+	 */
+	info->sinfo_ppid = ntohl(chunk->subh.data_hdr->ppid);
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
+	 *
+	 * sinfo_flags: 16 bits (unsigned integer)
+	 *
+	 * This field may contain any of the following flags and is composed of
+	 * a bitwise OR of these values.
+	 *
+	 * recvmsg() flags:
+	 *
+	 * MSG_UNORDERED - This flag is present when the message was sent
+	 *                 non-ordered.
+	 */
+	if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
+		info->sinfo_flags |= MSG_UNORDERED;
+
+		/* sinfo_cumtsn: 32 bit (unsigned integer)
+		 *
+		 * This field will hold the current cumulative TSN as
+		 * known by the underlying SCTP layer.  Note this field is
+		 * ignored when sending and only valid for a receive
+		 * operation when sinfo_flags are set to MSG_UNORDERED.
+		 */
+		info->sinfo_cumtsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
+	}
+
+	/* Note:  For reassembly, we need to have the fragmentation bits.
+	 * For now, merge these into the msg_flags, since those bit
+	 * possitions are not used.
+	 */
+	event->msg_flags |= chunk->chunk_hdr->flags;
+
+	/* With 04 draft, tsn moves into sndrcvinfo. */
+	info->sinfo_tsn = ntohl(chunk->subh.data_hdr->tsn);
+
+	/* Context is not used on receive. */
+	info->sinfo_context = 0;
+
+	/* Sockets API Extensions for SCTP
+	 * Section 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
+	 *
+	 * sinfo_assoc_id: sizeof (sctp_assoc_t)
+	 *
+	 * The association handle field, sinfo_assoc_id, holds the identifier
+	 * for the association announced in the COMMUNICATION_UP notification.
+	 * All notifications for a given association have the same identifier.
+	 * Ignored for TCP-style sockets.
+	 */
+	info->sinfo_assoc_id = sctp_assoc2id(asoc);
+
+	return event;
+
+fail_init:
+	kfree_skb(skb);
+
+fail:
+	return NULL;
+}
+
+/* Create a partial delivery related event.
+ *
+ * 5.3.1.7 SCTP_PARTIAL_DELIVERY_EVENT
+ *
+ *   When a reciever is engaged in a partial delivery of a
+ *   message this notification will be used to inidicate
+ *   various events.
+ */
+struct sctp_ulpevent *sctp_ulpevent_make_pdapi(
+	const struct sctp_association *asoc, __u32 indication, int gfp)
+{
+	struct sctp_ulpevent *event;
+	struct sctp_rcv_pdapi_event *pd;
+	struct sk_buff *skb;
+
+	event = sctp_ulpevent_new(sizeof(struct sctp_assoc_change),
+				  MSG_NOTIFICATION, gfp);
+	if (!event)
+		goto fail;
+
+	skb = sctp_event2skb(event);
+	pd = (struct sctp_rcv_pdapi_event *)
+		skb_put(skb, sizeof(struct sctp_rcv_pdapi_event));
+
+	/* pdapi_type
+	 *   It should be SCTP_PARTIAL_DELIVERY_EVENT
+	 *
+	 * pdapi_flags: 16 bits (unsigned integer)
+	 *   Currently unused.
+	 */
+	pd->pdapi_type = SCTP_PARTIAL_DELIVERY_EVENT;
+	pd->pdapi_flags = 0;
+
+	/* pdapi_length: 32 bits (unsigned integer)
+	 *
+	 * This field is the total length of the notification data, including
+	 * the notification header.  It will generally be sizeof (struct
+	 * sctp_rcv_pdapi_event).
+	 */
+	pd->pdapi_length = sizeof(struct sctp_rcv_pdapi_event);
+
+        /*  pdapi_indication: 32 bits (unsigned integer)
+	 *
+	 * This field holds the indication being sent to the application.
+	 */
+	pd->pdapi_indication = indication;
+
+	/*  pdapi_assoc_id: sizeof (sctp_assoc_t)
+	 *
+	 * The association id field, holds the identifier for the association.
+	 */
+	pd->pdapi_assoc_id = sctp_assoc2id(asoc);
+
+	return event;
+fail:
+	return NULL;
+}
+
+/* Return the notification type, assuming this is a notification
+ * event.
+ */
+__u16 sctp_ulpevent_get_notification_type(const struct sctp_ulpevent *event)
+{
+	union sctp_notification *notification;
+	struct sk_buff *skb;
+
+	skb = sctp_event2skb((struct sctp_ulpevent *)event);
+	notification = (union sctp_notification *) skb->data;
+	return notification->h.sn_type;
+}
+
+/* Copy out the sndrcvinfo into a msghdr.  */
+void sctp_ulpevent_read_sndrcvinfo(const struct sctp_ulpevent *event,
+				   struct msghdr *msghdr)
+{
+	if (!sctp_ulpevent_is_notification(event)) {
+		put_cmsg(msghdr, IPPROTO_SCTP, SCTP_SNDRCV,
+			 sizeof(struct sctp_sndrcvinfo),
+			 (void *) &event->sndrcvinfo);
+	}
+}
+
+/* Do accounting for bytes just read by user.  */
+static void sctp_rcvmsg_rfree(struct sk_buff *skb)
+{
+	struct sctp_association *asoc;
+	struct sctp_ulpevent *event;
+
+	/* Current stack structures assume that the rcv buffer is
+	 * per socket.   For UDP style sockets this is not true as
+	 * multiple associations may be on a single UDP-style socket.
+	 * Use the local private area of the skb to track the owning
+	 * association.
+	 */
+	event = sctp_skb2event(skb);
+	asoc = event->event_asoc;
+	sctp_assoc_rwnd_increase(asoc, skb_headlen(skb));
+	sctp_association_put(asoc);
+}
+
+/* Charge receive window for bytes received.  */
+static void sctp_ulpevent_set_owner_r(struct sk_buff *skb,
+				      struct sctp_association *asoc)
+{
+	struct sctp_ulpevent *event;
+
+	/* The current stack structures assume that the rcv buffer is
+	 * per socket.  For UDP-style sockets this is not true as
+	 * multiple associations may be on a single UDP-style socket.
+	 * We use the local private area of the skb to track the owning
+	 * association.
+	 */
+	sctp_association_hold(asoc);
+	skb->sk = asoc->base.sk;
+	event = sctp_skb2event(skb);
+	event->event_asoc = asoc;
+
+	skb->destructor = sctp_rcvmsg_rfree;
+
+	sctp_assoc_rwnd_decrease(asoc, skb_headlen(skb));
+}
+
+/* A simple destructor to give up the reference to the association. */
+static void sctp_ulpevent_rfree(struct sk_buff *skb)
+{
+	struct sctp_ulpevent *event;
+
+	event = sctp_skb2event(skb);
+	sctp_association_put(event->event_asoc);
+}
+
+/* Hold the association in case the msg_name needs read out of
+ * the association.
+ */
+static void sctp_ulpevent_set_owner(struct sk_buff *skb,
+				    const struct sctp_association *asoc)
+{
+	struct sctp_ulpevent *event;
+
+	/* Cast away the const, as we are just wanting to
+	 * bump the reference count.
+	 */
+	sctp_association_hold((struct sctp_association *)asoc);
+	skb->sk = asoc->base.sk;
+	event = sctp_skb2event(skb);
+	event->event_asoc = (struct sctp_association *)asoc;
+	skb->destructor = sctp_ulpevent_rfree;
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)