Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 6575 insertions, 0 deletions

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
new file mode 100644
index 000000000..1e82c5165
--- /dev/null
+++ b/net/sctp/sm_statefuns.c
@@ -0,0 +1,6575 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* SCTP kernel implementation
+ * (C) Copyright IBM Corp. 2001, 2004
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001-2002 Intel Corp.
+ * Copyright (c) 2002      Nokia Corp.
+ *
+ * This is part of the SCTP Linux Kernel Implementation.
+ *
+ * These are the state functions for the state machine.
+ *
+ * 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>
+ *    Mathew Kotowsky       <kotowsky@sctp.org>
+ *    Sridhar Samudrala     <samudrala@us.ibm.com>
+ *    Jon Grimm             <jgrimm@us.ibm.com>
+ *    Hui Huang 	    <hui.huang@nokia.com>
+ *    Dajiang Zhang 	    <dajiang.zhang@nokia.com>
+ *    Daisy Chang	    <daisyc@us.ibm.com>
+ *    Ardelle Fan	    <ardelle.fan@intel.com>
+ *    Ryan Layer	    <rmlayer@us.ibm.com>
+ *    Kevin Gao		    <kevin.gao@intel.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/net.h>
+#include <linux/inet.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <net/inet_ecn.h>
+#include <linux/skbuff.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+#include <net/sctp/structs.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/sctp.h>
+
+static struct sctp_packet *sctp_abort_pkt_new(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					struct sctp_chunk *chunk,
+					const void *payload, size_t paylen);
+static int sctp_eat_data(const struct sctp_association *asoc,
+			 struct sctp_chunk *chunk,
+			 struct sctp_cmd_seq *commands);
+static struct sctp_packet *sctp_ootb_pkt_new(
+					struct net *net,
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk);
+static void sctp_send_stale_cookie_err(struct net *net,
+				       const struct sctp_endpoint *ep,
+				       const struct sctp_association *asoc,
+				       const struct sctp_chunk *chunk,
+				       struct sctp_cmd_seq *commands,
+				       struct sctp_chunk *err_chunk);
+static enum sctp_disposition sctp_sf_do_5_2_6_stale(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands);
+static enum sctp_disposition sctp_sf_shut_8_4_5(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands);
+static enum sctp_disposition sctp_sf_tabort_8_4_8(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands);
+static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
+
+static enum sctp_disposition sctp_stop_t1_and_abort(
+					struct net *net,
+					struct sctp_cmd_seq *commands,
+					__be16 error, int sk_err,
+					const struct sctp_association *asoc,
+					struct sctp_transport *transport);
+
+static enum sctp_disposition sctp_sf_abort_violation(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					void *arg,
+					struct sctp_cmd_seq *commands,
+					const __u8 *payload,
+					const size_t paylen);
+
+static enum sctp_disposition sctp_sf_violation_chunklen(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands);
+
+static enum sctp_disposition sctp_sf_violation_paramlen(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg, void *ext,
+					struct sctp_cmd_seq *commands);
+
+static enum sctp_disposition sctp_sf_violation_ctsn(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands);
+
+static enum sctp_disposition sctp_sf_violation_chunk(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands);
+
+static enum sctp_ierror sctp_sf_authenticate(
+					const struct sctp_association *asoc,
+					struct sctp_chunk *chunk);
+
+static enum sctp_disposition __sctp_sf_do_9_1_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands);
+
+static enum sctp_disposition
+__sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
+			   const struct sctp_association *asoc,
+			   const union sctp_subtype type, void *arg,
+			   struct sctp_cmd_seq *commands);
+
+/* Small helper function that checks if the chunk length
+ * is of the appropriate length.  The 'required_length' argument
+ * is set to be the size of a specific chunk we are testing.
+ * Return Values:  true  = Valid length
+ * 		   false = Invalid length
+ *
+ */
+static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
+					   __u16 required_length)
+{
+	__u16 chunk_length = ntohs(chunk->chunk_hdr->length);
+
+	/* Previously already marked? */
+	if (unlikely(chunk->pdiscard))
+		return false;
+	if (unlikely(chunk_length < required_length))
+		return false;
+
+	return true;
+}
+
+/* Check for format error in an ABORT chunk */
+static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk)
+{
+	struct sctp_errhdr *err;
+
+	sctp_walk_errors(err, chunk->chunk_hdr);
+
+	return (void *)err == (void *)chunk->chunk_end;
+}
+
+/**********************************************************
+ * These are the state functions for handling chunk events.
+ **********************************************************/
+
+/*
+ * Process the final SHUTDOWN COMPLETE.
+ *
+ * Section: 4 (C) (diagram), 9.2
+ * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
+ * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
+ * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
+ * should stop the T2-shutdown timer and remove all knowledge of the
+ * association (and thus the association enters the CLOSED state).
+ *
+ * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
+ * C) Rules for packet carrying SHUTDOWN COMPLETE:
+ * ...
+ * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
+ *   if the Verification Tag field of the packet matches its own tag and
+ *   the T bit is not set
+ *   OR
+ *   it is set to its peer's tag and the T bit is set in the Chunk
+ *   Flags.
+ *   Otherwise, the receiver MUST silently discard the packet
+ *   and take no further action.  An endpoint MUST ignore the
+ *   SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_4_C(struct net *net,
+				     const struct sctp_endpoint *ep,
+				     const struct sctp_association *asoc,
+				     const union sctp_subtype type,
+				     void *arg, struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_ulpevent *ev;
+
+	if (!sctp_vtag_verify_either(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* RFC 2960 6.10 Bundling
+	 *
+	 * An endpoint MUST NOT bundle INIT, INIT ACK or
+	 * SHUTDOWN COMPLETE with any other chunks.
+	 */
+	if (!chunk->singleton)
+		return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* RFC 2960 10.2 SCTP-to-ULP
+	 *
+	 * H) SHUTDOWN COMPLETE notification
+	 *
+	 * When SCTP completes the shutdown procedures (section 9.2) this
+	 * notification is passed to the upper layer.
+	 */
+	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
+					     0, 0, 0, NULL, GFP_ATOMIC);
+	if (ev)
+		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+				SCTP_ULPEVENT(ev));
+
+	/* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
+	 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
+	 * not the chunk should be discarded. If the endpoint is in
+	 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
+	 * T2-shutdown timer and remove all knowledge of the
+	 * association (and thus the association enters the CLOSED
+	 * state).
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_CLOSED));
+
+	SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
+	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
+
+	return SCTP_DISPOSITION_DELETE_TCB;
+}
+
+/*
+ * Respond to a normal INIT chunk.
+ * We are the side that is being asked for an association.
+ *
+ * Section: 5.1 Normal Establishment of an Association, B
+ * B) "Z" shall respond immediately with an INIT ACK chunk.  The
+ *    destination IP address of the INIT ACK MUST be set to the source
+ *    IP address of the INIT to which this INIT ACK is responding.  In
+ *    the response, besides filling in other parameters, "Z" must set the
+ *    Verification Tag field to Tag_A, and also provide its own
+ *    Verification Tag (Tag_Z) in the Initiate Tag field.
+ *
+ * Verification Tag: Must be 0.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg, *repl, *err_chunk;
+	struct sctp_unrecognized_param *unk_param;
+	struct sctp_association *new_asoc;
+	struct sctp_packet *packet;
+	int len;
+
+	/* Update socket peer label if first association. */
+	if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+					chunk->skb))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* 6.10 Bundling
+	 * An endpoint MUST NOT bundle INIT, INIT ACK or
+	 * SHUTDOWN COMPLETE with any other chunks.
+	 *
+	 * IG Section 2.11.2
+	 * Furthermore, we require that the receiver of an INIT chunk MUST
+	 * enforce these rules by silently discarding an arriving packet
+	 * with an INIT chunk that is bundled with other chunks.
+	 */
+	if (!chunk->singleton)
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the INIT chunk has a valid length.
+	 * Normally, this would cause an ABORT with a Protocol Violation
+	 * error, but since we don't have an association, we'll
+	 * just discard the packet.
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* If the packet is an OOTB packet which is temporarily on the
+	 * control endpoint, respond with an ABORT.
+	 */
+	if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
+		SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
+		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
+	}
+
+	/* 3.1 A packet containing an INIT chunk MUST have a zero Verification
+	 * Tag.
+	 */
+	if (chunk->sctp_hdr->vtag != 0)
+		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
+
+	/* If the INIT is coming toward a closing socket, we'll send back
+	 * and ABORT.  Essentially, this catches the race of INIT being
+	 * backloged to the socket at the same time as the user isses close().
+	 * Since the socket and all its associations are going away, we
+	 * can treat this OOTB
+	 */
+	if (sctp_sstate(ep->base.sk, CLOSING))
+		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
+
+	/* Verify the INIT chunk before processing it. */
+	err_chunk = NULL;
+	if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
+			      (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
+			      &err_chunk)) {
+		/* This chunk contains fatal error. It is to be discarded.
+		 * Send an ABORT, with causes if there is any.
+		 */
+		if (err_chunk) {
+			packet = sctp_abort_pkt_new(net, ep, asoc, arg,
+					(__u8 *)(err_chunk->chunk_hdr) +
+					sizeof(struct sctp_chunkhdr),
+					ntohs(err_chunk->chunk_hdr->length) -
+					sizeof(struct sctp_chunkhdr));
+
+			sctp_chunk_free(err_chunk);
+
+			if (packet) {
+				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
+						SCTP_PACKET(packet));
+				SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+				return SCTP_DISPOSITION_CONSUME;
+			} else {
+				return SCTP_DISPOSITION_NOMEM;
+			}
+		} else {
+			return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
+						    commands);
+		}
+	}
+
+	/* Grab the INIT header.  */
+	chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
+
+	/* Tag the variable length parameters.  */
+	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
+
+	new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
+	if (!new_asoc)
+		goto nomem;
+
+	if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
+					     sctp_scope(sctp_source(chunk)),
+					     GFP_ATOMIC) < 0)
+		goto nomem_init;
+
+	/* The call, sctp_process_init(), can fail on memory allocation.  */
+	if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
+			       (struct sctp_init_chunk *)chunk->chunk_hdr,
+			       GFP_ATOMIC))
+		goto nomem_init;
+
+	/* B) "Z" shall respond immediately with an INIT ACK chunk.  */
+
+	/* If there are errors need to be reported for unknown parameters,
+	 * make sure to reserve enough room in the INIT ACK for them.
+	 */
+	len = 0;
+	if (err_chunk)
+		len = ntohs(err_chunk->chunk_hdr->length) -
+		      sizeof(struct sctp_chunkhdr);
+
+	repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
+	if (!repl)
+		goto nomem_init;
+
+	/* If there are errors need to be reported for unknown parameters,
+	 * include them in the outgoing INIT ACK as "Unrecognized parameter"
+	 * parameter.
+	 */
+	if (err_chunk) {
+		/* Get the "Unrecognized parameter" parameter(s) out of the
+		 * ERROR chunk generated by sctp_verify_init(). Since the
+		 * error cause code for "unknown parameter" and the
+		 * "Unrecognized parameter" type is the same, we can
+		 * construct the parameters in INIT ACK by copying the
+		 * ERROR causes over.
+		 */
+		unk_param = (struct sctp_unrecognized_param *)
+			    ((__u8 *)(err_chunk->chunk_hdr) +
+			    sizeof(struct sctp_chunkhdr));
+		/* Replace the cause code with the "Unrecognized parameter"
+		 * parameter type.
+		 */
+		sctp_addto_chunk(repl, len, unk_param);
+		sctp_chunk_free(err_chunk);
+	}
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+
+	/*
+	 * Note:  After sending out INIT ACK with the State Cookie parameter,
+	 * "Z" MUST NOT allocate any resources, nor keep any states for the
+	 * new association.  Otherwise, "Z" will be vulnerable to resource
+	 * attacks.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
+
+	return SCTP_DISPOSITION_DELETE_TCB;
+
+nomem_init:
+	sctp_association_free(new_asoc);
+nomem:
+	if (err_chunk)
+		sctp_chunk_free(err_chunk);
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Respond to a normal INIT ACK chunk.
+ * We are the side that is initiating the association.
+ *
+ * Section: 5.1 Normal Establishment of an Association, C
+ * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
+ *    timer and leave COOKIE-WAIT state. "A" shall then send the State
+ *    Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
+ *    the T1-cookie timer, and enter the COOKIE-ECHOED state.
+ *
+ *    Note: The COOKIE ECHO chunk can be bundled with any pending outbound
+ *    DATA chunks, but it MUST be the first chunk in the packet and
+ *    until the COOKIE ACK is returned the sender MUST NOT send any
+ *    other packets to the peer.
+ *
+ * Verification Tag: 3.3.3
+ *   If the value of the Initiate Tag in a received INIT ACK chunk is
+ *   found to be 0, the receiver MUST treat it as an error and close the
+ *   association by transmitting an ABORT.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
+					  const struct sctp_endpoint *ep,
+					  const struct sctp_association *asoc,
+					  const union sctp_subtype type,
+					  void *arg,
+					  struct sctp_cmd_seq *commands)
+{
+	struct sctp_init_chunk *initchunk;
+	struct sctp_chunk *chunk = arg;
+	struct sctp_chunk *err_chunk;
+	struct sctp_packet *packet;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* 6.10 Bundling
+	 * An endpoint MUST NOT bundle INIT, INIT ACK or
+	 * SHUTDOWN COMPLETE with any other chunks.
+	 */
+	if (!chunk->singleton)
+		return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the INIT-ACK chunk has a valid length */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+	/* Grab the INIT header.  */
+	chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
+
+	/* Verify the INIT chunk before processing it. */
+	err_chunk = NULL;
+	if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
+			      (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
+			      &err_chunk)) {
+
+		enum sctp_error error = SCTP_ERROR_NO_RESOURCE;
+
+		/* This chunk contains fatal error. It is to be discarded.
+		 * Send an ABORT, with causes.  If there are no causes,
+		 * then there wasn't enough memory.  Just terminate
+		 * the association.
+		 */
+		if (err_chunk) {
+			packet = sctp_abort_pkt_new(net, ep, asoc, arg,
+					(__u8 *)(err_chunk->chunk_hdr) +
+					sizeof(struct sctp_chunkhdr),
+					ntohs(err_chunk->chunk_hdr->length) -
+					sizeof(struct sctp_chunkhdr));
+
+			sctp_chunk_free(err_chunk);
+
+			if (packet) {
+				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
+						SCTP_PACKET(packet));
+				SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+				error = SCTP_ERROR_INV_PARAM;
+			}
+		}
+
+		/* SCTP-AUTH, Section 6.3:
+		 *    It should be noted that if the receiver wants to tear
+		 *    down an association in an authenticated way only, the
+		 *    handling of malformed packets should not result in
+		 *    tearing down the association.
+		 *
+		 * This means that if we only want to abort associations
+		 * in an authenticated way (i.e AUTH+ABORT), then we
+		 * can't destroy this association just because the packet
+		 * was malformed.
+		 */
+		if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
+			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
+						asoc, chunk->transport);
+	}
+
+	/* Tag the variable length parameters.  Note that we never
+	 * convert the parameters in an INIT chunk.
+	 */
+	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
+
+	initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
+			SCTP_PEER_INIT(initchunk));
+
+	/* Reset init error count upon receipt of INIT-ACK.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
+
+	/* 5.1 C) "A" shall stop the T1-init timer and leave
+	 * COOKIE-WAIT state.  "A" shall then ... start the T1-cookie
+	 * timer, and enter the COOKIE-ECHOED state.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
+
+	/* SCTP-AUTH: genereate the assocition shared keys so that
+	 * we can potentially signe the COOKIE-ECHO.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
+
+	/* 5.1 C) "A" shall then send the State Cookie received in the
+	 * INIT ACK chunk in a COOKIE ECHO chunk, ...
+	 */
+	/* If there is any errors to report, send the ERROR chunk generated
+	 * for unknown parameters as well.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
+			SCTP_CHUNK(err_chunk));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk,
+				   const struct sctp_association *asoc)
+{
+	struct sctp_chunk auth;
+
+	if (!chunk->auth_chunk)
+		return true;
+
+	/* SCTP-AUTH:  auth_chunk pointer is only set when the cookie-echo
+	 * is supposed to be authenticated and we have to do delayed
+	 * authentication.  We've just recreated the association using
+	 * the information in the cookie and now it's much easier to
+	 * do the authentication.
+	 */
+
+	/* Make sure that we and the peer are AUTH capable */
+	if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
+		return false;
+
+	/* set-up our fake chunk so that we can process it */
+	auth.skb = chunk->auth_chunk;
+	auth.asoc = chunk->asoc;
+	auth.sctp_hdr = chunk->sctp_hdr;
+	auth.chunk_hdr = (struct sctp_chunkhdr *)
+				skb_push(chunk->auth_chunk,
+					 sizeof(struct sctp_chunkhdr));
+	skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr));
+	auth.transport = chunk->transport;
+
+	return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR;
+}
+
+/*
+ * Respond to a normal COOKIE ECHO chunk.
+ * We are the side that is being asked for an association.
+ *
+ * Section: 5.1 Normal Establishment of an Association, D
+ * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
+ *    with a COOKIE ACK chunk after building a TCB and moving to
+ *    the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
+ *    any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
+ *    chunk MUST be the first chunk in the packet.
+ *
+ *   IMPLEMENTATION NOTE: An implementation may choose to send the
+ *   Communication Up notification to the SCTP user upon reception
+ *   of a valid COOKIE ECHO chunk.
+ *
+ * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
+ * D) Rules for packet carrying a COOKIE ECHO
+ *
+ * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
+ *   Initial Tag received in the INIT ACK.
+ *
+ * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
+					 const struct sctp_endpoint *ep,
+					 const struct sctp_association *asoc,
+					 const union sctp_subtype type,
+					 void *arg,
+					 struct sctp_cmd_seq *commands)
+{
+	struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL;
+	struct sctp_association *new_asoc;
+	struct sctp_init_chunk *peer_init;
+	struct sctp_chunk *chunk = arg;
+	struct sctp_chunk *err_chk_p;
+	struct sctp_chunk *repl;
+	struct sock *sk;
+	int error = 0;
+
+	if (asoc && !sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* If the packet is an OOTB packet which is temporarily on the
+	 * control endpoint, respond with an ABORT.
+	 */
+	if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
+		SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
+		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
+	}
+
+	/* Make sure that the COOKIE_ECHO chunk has a valid length.
+	 * In this case, we check that we have enough for at least a
+	 * chunk header.  More detailed verification is done
+	 * in sctp_unpack_cookie().
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* If the endpoint is not listening or if the number of associations
+	 * on the TCP-style socket exceed the max backlog, respond with an
+	 * ABORT.
+	 */
+	sk = ep->base.sk;
+	if (!sctp_sstate(sk, LISTENING) ||
+	    (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
+		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
+
+	/* "Decode" the chunk.  We have no optional parameters so we
+	 * are in good shape.
+	 */
+	chunk->subh.cookie_hdr =
+		(struct sctp_signed_cookie *)chunk->skb->data;
+	if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
+					 sizeof(struct sctp_chunkhdr)))
+		goto nomem;
+
+	/* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
+	 * "Z" will reply with a COOKIE ACK chunk after building a TCB
+	 * and moving to the ESTABLISHED state.
+	 */
+	new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
+				      &err_chk_p);
+
+	/* FIXME:
+	 * If the re-build failed, what is the proper error path
+	 * from here?
+	 *
+	 * [We should abort the association. --piggy]
+	 */
+	if (!new_asoc) {
+		/* FIXME: Several errors are possible.  A bad cookie should
+		 * be silently discarded, but think about logging it too.
+		 */
+		switch (error) {
+		case -SCTP_IERROR_NOMEM:
+			goto nomem;
+
+		case -SCTP_IERROR_STALE_COOKIE:
+			sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
+						   err_chk_p);
+			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+		case -SCTP_IERROR_BAD_SIG:
+		default:
+			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+		}
+	}
+
+
+	/* Delay state machine commands until later.
+	 *
+	 * Re-build the bind address for the association is done in
+	 * the sctp_unpack_cookie() already.
+	 */
+	/* This is a brand-new association, so these are not yet side
+	 * effects--it is safe to run them here.
+	 */
+	peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
+
+	if (!sctp_process_init(new_asoc, chunk,
+			       &chunk->subh.cookie_hdr->c.peer_addr,
+			       peer_init, GFP_ATOMIC))
+		goto nomem_init;
+
+	/* SCTP-AUTH:  Now that we've populate required fields in
+	 * sctp_process_init, set up the assocaition shared keys as
+	 * necessary so that we can potentially authenticate the ACK
+	 */
+	error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
+	if (error)
+		goto nomem_init;
+
+	if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) {
+		sctp_association_free(new_asoc);
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	repl = sctp_make_cookie_ack(new_asoc, chunk);
+	if (!repl)
+		goto nomem_init;
+
+	/* RFC 2960 5.1 Normal Establishment of an Association
+	 *
+	 * D) IMPLEMENTATION NOTE: An implementation may choose to
+	 * send the Communication Up notification to the SCTP user
+	 * upon reception of a valid COOKIE ECHO chunk.
+	 */
+	ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
+					     new_asoc->c.sinit_num_ostreams,
+					     new_asoc->c.sinit_max_instreams,
+					     NULL, GFP_ATOMIC);
+	if (!ev)
+		goto nomem_ev;
+
+	/* Sockets API Draft Section 5.3.1.6
+	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
+	 * delivers this notification to inform the application that of the
+	 * peers requested adaptation layer.
+	 */
+	if (new_asoc->peer.adaptation_ind) {
+		ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
+							    GFP_ATOMIC);
+		if (!ai_ev)
+			goto nomem_aiev;
+	}
+
+	if (!new_asoc->peer.auth_capable) {
+		auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
+						     SCTP_AUTH_NO_AUTH,
+						     GFP_ATOMIC);
+		if (!auth_ev)
+			goto nomem_authev;
+	}
+
+	/* Add all the state machine commands now since we've created
+	 * everything.  This way we don't introduce memory corruptions
+	 * during side-effect processing and correclty count established
+	 * associations.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_ESTABLISHED));
+	SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
+	SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
+	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
+
+	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
+
+	/* This will send the COOKIE ACK */
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+
+	/* Queue the ASSOC_CHANGE event */
+	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
+
+	/* Send up the Adaptation Layer Indication event */
+	if (ai_ev)
+		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+				SCTP_ULPEVENT(ai_ev));
+
+	if (auth_ev)
+		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+				SCTP_ULPEVENT(auth_ev));
+
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem_authev:
+	sctp_ulpevent_free(ai_ev);
+nomem_aiev:
+	sctp_ulpevent_free(ev);
+nomem_ev:
+	sctp_chunk_free(repl);
+nomem_init:
+	sctp_association_free(new_asoc);
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Respond to a normal COOKIE ACK chunk.
+ * We are the side that is asking for an association.
+ *
+ * RFC 2960 5.1 Normal Establishment of an Association
+ *
+ * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
+ *    COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
+ *    timer. It may also notify its ULP about the successful
+ *    establishment of the association with a Communication Up
+ *    notification (see Section 10).
+ *
+ * Verification Tag:
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
+					 const struct sctp_endpoint *ep,
+					 const struct sctp_association *asoc,
+					 const union sctp_subtype type,
+					 void *arg,
+					 struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_ulpevent *ev;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Verify that the chunk length for the COOKIE-ACK is OK.
+	 * If we don't do this, any bundled chunks may be junked.
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* Reset init error count upon receipt of COOKIE-ACK,
+	 * to avoid problems with the managemement of this
+	 * counter in stale cookie situations when a transition back
+	 * from the COOKIE-ECHOED state to the COOKIE-WAIT
+	 * state is performed.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
+
+	/* Set peer label for connection. */
+	security_inet_conn_established(ep->base.sk, chunk->skb);
+
+	/* RFC 2960 5.1 Normal Establishment of an Association
+	 *
+	 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
+	 * from the COOKIE-ECHOED state to the ESTABLISHED state,
+	 * stopping the T1-cookie timer.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_ESTABLISHED));
+	SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
+	SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
+	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
+	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
+
+	/* It may also notify its ULP about the successful
+	 * establishment of the association with a Communication Up
+	 * notification (see Section 10).
+	 */
+	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
+					     0, asoc->c.sinit_num_ostreams,
+					     asoc->c.sinit_max_instreams,
+					     NULL, GFP_ATOMIC);
+
+	if (!ev)
+		goto nomem;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
+
+	/* Sockets API Draft Section 5.3.1.6
+	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
+	 * delivers this notification to inform the application that of the
+	 * peers requested adaptation layer.
+	 */
+	if (asoc->peer.adaptation_ind) {
+		ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
+		if (!ev)
+			goto nomem;
+
+		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+				SCTP_ULPEVENT(ev));
+	}
+
+	if (!asoc->peer.auth_capable) {
+		ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
+						GFP_ATOMIC);
+		if (!ev)
+			goto nomem;
+		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+				SCTP_ULPEVENT(ev));
+	}
+
+	return SCTP_DISPOSITION_CONSUME;
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/* Generate and sendout a heartbeat packet.  */
+static enum sctp_disposition sctp_sf_heartbeat(
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_transport *transport = (struct sctp_transport *) arg;
+	struct sctp_chunk *reply;
+
+	/* Send a heartbeat to our peer.  */
+	reply = sctp_make_heartbeat(asoc, transport);
+	if (!reply)
+		return SCTP_DISPOSITION_NOMEM;
+
+	/* Set rto_pending indicating that an RTT measurement
+	 * is started with this heartbeat chunk.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
+			SCTP_TRANSPORT(transport));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/* Generate a HEARTBEAT packet on the given transport.  */
+enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	struct sctp_transport *transport = (struct sctp_transport *) arg;
+
+	if (asoc->overall_error_count >= asoc->max_retrans) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ETIMEDOUT));
+		/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
+		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+				SCTP_PERR(SCTP_ERROR_NO_ERROR));
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		return SCTP_DISPOSITION_DELETE_TCB;
+	}
+
+	/* Section 3.3.5.
+	 * The Sender-specific Heartbeat Info field should normally include
+	 * information about the sender's current time when this HEARTBEAT
+	 * chunk is sent and the destination transport address to which this
+	 * HEARTBEAT is sent (see Section 8.3).
+	 */
+
+	if (transport->param_flags & SPP_HB_ENABLE) {
+		if (SCTP_DISPOSITION_NOMEM ==
+				sctp_sf_heartbeat(ep, asoc, type, arg,
+						  commands))
+			return SCTP_DISPOSITION_NOMEM;
+
+		/* Set transport error counter and association error counter
+		 * when sending heartbeat.
+		 */
+		sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
+				SCTP_TRANSPORT(transport));
+	}
+	sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
+			SCTP_TRANSPORT(transport));
+	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
+			SCTP_TRANSPORT(transport));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/* resend asoc strreset_chunk.  */
+enum sctp_disposition sctp_sf_send_reconf(struct net *net,
+					  const struct sctp_endpoint *ep,
+					  const struct sctp_association *asoc,
+					  const union sctp_subtype type,
+					  void *arg,
+					  struct sctp_cmd_seq *commands)
+{
+	struct sctp_transport *transport = arg;
+
+	if (asoc->overall_error_count >= asoc->max_retrans) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ETIMEDOUT));
+		/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
+		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+				SCTP_PERR(SCTP_ERROR_NO_ERROR));
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		return SCTP_DISPOSITION_DELETE_TCB;
+	}
+
+	sctp_chunk_hold(asoc->strreset_chunk);
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+			SCTP_CHUNK(asoc->strreset_chunk));
+	sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Process an heartbeat request.
+ *
+ * Section: 8.3 Path Heartbeat
+ * The receiver of the HEARTBEAT should immediately respond with a
+ * HEARTBEAT ACK that contains the Heartbeat Information field copied
+ * from the received HEARTBEAT chunk.
+ *
+ * Verification Tag:  8.5 Verification Tag [Normal verification]
+ * When receiving an SCTP packet, the endpoint MUST ensure that the
+ * value in the Verification Tag field of the received SCTP packet
+ * matches its own Tag. If the received Verification Tag value does not
+ * match the receiver's own tag value, the receiver shall silently
+ * discard the packet and shall not process it any further except for
+ * those cases listed in Section 8.5.1 below.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_beat_8_3(struct net *net,
+				       const struct sctp_endpoint *ep,
+				       const struct sctp_association *asoc,
+				       const union sctp_subtype type,
+				       void *arg, struct sctp_cmd_seq *commands)
+{
+	struct sctp_paramhdr *param_hdr;
+	struct sctp_chunk *chunk = arg;
+	struct sctp_chunk *reply;
+	size_t paylen = 0;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the HEARTBEAT chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk,
+				     sizeof(struct sctp_heartbeat_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* 8.3 The receiver of the HEARTBEAT should immediately
+	 * respond with a HEARTBEAT ACK that contains the Heartbeat
+	 * Information field copied from the received HEARTBEAT chunk.
+	 */
+	chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data;
+	param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr;
+	paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr);
+
+	if (ntohs(param_hdr->length) > paylen)
+		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
+						  param_hdr, commands);
+
+	if (!pskb_pull(chunk->skb, paylen))
+		goto nomem;
+
+	reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
+	if (!reply)
+		goto nomem;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Process the returning HEARTBEAT ACK.
+ *
+ * Section: 8.3 Path Heartbeat
+ * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
+ * should clear the error counter of the destination transport
+ * address to which the HEARTBEAT was sent, and mark the destination
+ * transport address as active if it is not so marked. The endpoint may
+ * optionally report to the upper layer when an inactive destination
+ * address is marked as active due to the reception of the latest
+ * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
+ * clear the association overall error count as well (as defined
+ * in section 8.1).
+ *
+ * The receiver of the HEARTBEAT ACK should also perform an RTT
+ * measurement for that destination transport address using the time
+ * value carried in the HEARTBEAT ACK chunk.
+ *
+ * Verification Tag:  8.5 Verification Tag [Normal verification]
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	struct sctp_sender_hb_info *hbinfo;
+	struct sctp_chunk *chunk = arg;
+	struct sctp_transport *link;
+	unsigned long max_interval;
+	union sctp_addr from_addr;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the HEARTBEAT-ACK chunk has a valid length.  */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) +
+					    sizeof(*hbinfo)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
+	/* Make sure that the length of the parameter is what we expect */
+	if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo))
+		return SCTP_DISPOSITION_DISCARD;
+
+	from_addr = hbinfo->daddr;
+	link = sctp_assoc_lookup_paddr(asoc, &from_addr);
+
+	/* This should never happen, but lets log it if so.  */
+	if (unlikely(!link)) {
+		if (from_addr.sa.sa_family == AF_INET6) {
+			net_warn_ratelimited("%s association %p could not find address %pI6\n",
+					     __func__,
+					     asoc,
+					     &from_addr.v6.sin6_addr);
+		} else {
+			net_warn_ratelimited("%s association %p could not find address %pI4\n",
+					     __func__,
+					     asoc,
+					     &from_addr.v4.sin_addr.s_addr);
+		}
+		return SCTP_DISPOSITION_DISCARD;
+	}
+
+	/* Validate the 64-bit random nonce. */
+	if (hbinfo->hb_nonce != link->hb_nonce)
+		return SCTP_DISPOSITION_DISCARD;
+
+	max_interval = link->hbinterval + link->rto;
+
+	/* Check if the timestamp looks valid.  */
+	if (time_after(hbinfo->sent_at, jiffies) ||
+	    time_after(jiffies, hbinfo->sent_at + max_interval)) {
+		pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
+			 "for transport:%p\n", __func__, link);
+
+		return SCTP_DISPOSITION_DISCARD;
+	}
+
+	/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
+	 * the HEARTBEAT should clear the error counter of the
+	 * destination transport address to which the HEARTBEAT was
+	 * sent and mark the destination transport address as active if
+	 * it is not so marked.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/* Helper function to send out an abort for the restart
+ * condition.
+ */
+static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
+				      struct sctp_chunk *init,
+				      struct sctp_cmd_seq *commands)
+{
+	struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
+	union sctp_addr_param *addrparm;
+	struct sctp_errhdr *errhdr;
+	char buffer[sizeof(*errhdr) + sizeof(*addrparm)];
+	struct sctp_endpoint *ep;
+	struct sctp_packet *pkt;
+	int len;
+
+	/* Build the error on the stack.   We are way to malloc crazy
+	 * throughout the code today.
+	 */
+	errhdr = (struct sctp_errhdr *)buffer;
+	addrparm = (union sctp_addr_param *)errhdr->variable;
+
+	/* Copy into a parm format. */
+	len = af->to_addr_param(ssa, addrparm);
+	len += sizeof(*errhdr);
+
+	errhdr->cause = SCTP_ERROR_RESTART;
+	errhdr->length = htons(len);
+
+	/* Assign to the control socket. */
+	ep = sctp_sk(net->sctp.ctl_sock)->ep;
+
+	/* Association is NULL since this may be a restart attack and we
+	 * want to send back the attacker's vtag.
+	 */
+	pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
+
+	if (!pkt)
+		goto out;
+	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
+
+	SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+
+	/* Discard the rest of the inbound packet. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
+
+out:
+	/* Even if there is no memory, treat as a failure so
+	 * the packet will get dropped.
+	 */
+	return 0;
+}
+
+static bool list_has_sctp_addr(const struct list_head *list,
+			       union sctp_addr *ipaddr)
+{
+	struct sctp_transport *addr;
+
+	list_for_each_entry(addr, list, transports) {
+		if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
+			return true;
+	}
+
+	return false;
+}
+/* A restart is occurring, check to make sure no new addresses
+ * are being added as we may be under a takeover attack.
+ */
+static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
+				       const struct sctp_association *asoc,
+				       struct sctp_chunk *init,
+				       struct sctp_cmd_seq *commands)
+{
+	struct net *net = new_asoc->base.net;
+	struct sctp_transport *new_addr;
+	int ret = 1;
+
+	/* Implementor's Guide - Section 5.2.2
+	 * ...
+	 * Before responding the endpoint MUST check to see if the
+	 * unexpected INIT adds new addresses to the association. If new
+	 * addresses are added to the association, the endpoint MUST respond
+	 * with an ABORT..
+	 */
+
+	/* Search through all current addresses and make sure
+	 * we aren't adding any new ones.
+	 */
+	list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
+			    transports) {
+		if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
+					&new_addr->ipaddr)) {
+			sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
+						   commands);
+			ret = 0;
+			break;
+		}
+	}
+
+	/* Return success if all addresses were found. */
+	return ret;
+}
+
+/* Populate the verification/tie tags based on overlapping INIT
+ * scenario.
+ *
+ * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
+ */
+static void sctp_tietags_populate(struct sctp_association *new_asoc,
+				  const struct sctp_association *asoc)
+{
+	switch (asoc->state) {
+
+	/* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
+
+	case SCTP_STATE_COOKIE_WAIT:
+		new_asoc->c.my_vtag     = asoc->c.my_vtag;
+		new_asoc->c.my_ttag     = asoc->c.my_vtag;
+		new_asoc->c.peer_ttag   = 0;
+		break;
+
+	case SCTP_STATE_COOKIE_ECHOED:
+		new_asoc->c.my_vtag     = asoc->c.my_vtag;
+		new_asoc->c.my_ttag     = asoc->c.my_vtag;
+		new_asoc->c.peer_ttag   = asoc->c.peer_vtag;
+		break;
+
+	/* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
+	 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
+	 */
+	default:
+		new_asoc->c.my_ttag   = asoc->c.my_vtag;
+		new_asoc->c.peer_ttag = asoc->c.peer_vtag;
+		break;
+	}
+
+	/* Other parameters for the endpoint SHOULD be copied from the
+	 * existing parameters of the association (e.g. number of
+	 * outbound streams) into the INIT ACK and cookie.
+	 */
+	new_asoc->rwnd                  = asoc->rwnd;
+	new_asoc->c.sinit_num_ostreams  = asoc->c.sinit_num_ostreams;
+	new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
+	new_asoc->c.initial_tsn         = asoc->c.initial_tsn;
+}
+
+/*
+ * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
+ * handling action.
+ *
+ * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
+ *
+ * Returns value representing action to be taken.   These action values
+ * correspond to Action/Description values in RFC 2960, Table 2.
+ */
+static char sctp_tietags_compare(struct sctp_association *new_asoc,
+				 const struct sctp_association *asoc)
+{
+	/* In this case, the peer may have restarted.  */
+	if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
+	    (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
+	    (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
+	    (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
+		return 'A';
+
+	/* Collision case B. */
+	if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
+	    ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
+	     (0 == asoc->c.peer_vtag))) {
+		return 'B';
+	}
+
+	/* Collision case D. */
+	if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
+	    (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
+		return 'D';
+
+	/* Collision case C. */
+	if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
+	    (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
+	    (0 == new_asoc->c.my_ttag) &&
+	    (0 == new_asoc->c.peer_ttag))
+		return 'C';
+
+	/* No match to any of the special cases; discard this packet. */
+	return 'E';
+}
+
+/* Common helper routine for both duplicate and simulataneous INIT
+ * chunk handling.
+ */
+static enum sctp_disposition sctp_sf_do_unexpected_init(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg, *repl, *err_chunk;
+	struct sctp_unrecognized_param *unk_param;
+	struct sctp_association *new_asoc;
+	enum sctp_disposition retval;
+	struct sctp_packet *packet;
+	int len;
+
+	/* Update socket peer label if first association. */
+	if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+					chunk->skb))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* 6.10 Bundling
+	 * An endpoint MUST NOT bundle INIT, INIT ACK or
+	 * SHUTDOWN COMPLETE with any other chunks.
+	 *
+	 * IG Section 2.11.2
+	 * Furthermore, we require that the receiver of an INIT chunk MUST
+	 * enforce these rules by silently discarding an arriving packet
+	 * with an INIT chunk that is bundled with other chunks.
+	 */
+	if (!chunk->singleton)
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the INIT chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* 3.1 A packet containing an INIT chunk MUST have a zero Verification
+	 * Tag.
+	 */
+	if (chunk->sctp_hdr->vtag != 0)
+		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
+
+	/* Grab the INIT header.  */
+	chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
+
+	/* Tag the variable length parameters.  */
+	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
+
+	/* Verify the INIT chunk before processing it. */
+	err_chunk = NULL;
+	if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
+			      (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
+			      &err_chunk)) {
+		/* This chunk contains fatal error. It is to be discarded.
+		 * Send an ABORT, with causes if there is any.
+		 */
+		if (err_chunk) {
+			packet = sctp_abort_pkt_new(net, ep, asoc, arg,
+					(__u8 *)(err_chunk->chunk_hdr) +
+					sizeof(struct sctp_chunkhdr),
+					ntohs(err_chunk->chunk_hdr->length) -
+					sizeof(struct sctp_chunkhdr));
+
+			if (packet) {
+				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
+						SCTP_PACKET(packet));
+				SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+				retval = SCTP_DISPOSITION_CONSUME;
+			} else {
+				retval = SCTP_DISPOSITION_NOMEM;
+			}
+			goto cleanup;
+		} else {
+			return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
+						    commands);
+		}
+	}
+
+	/*
+	 * Other parameters for the endpoint SHOULD be copied from the
+	 * existing parameters of the association (e.g. number of
+	 * outbound streams) into the INIT ACK and cookie.
+	 * FIXME:  We are copying parameters from the endpoint not the
+	 * association.
+	 */
+	new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
+	if (!new_asoc)
+		goto nomem;
+
+	if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
+				sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
+		goto nomem;
+
+	/* In the outbound INIT ACK the endpoint MUST copy its current
+	 * Verification Tag and Peers Verification tag into a reserved
+	 * place (local tie-tag and per tie-tag) within the state cookie.
+	 */
+	if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
+			       (struct sctp_init_chunk *)chunk->chunk_hdr,
+			       GFP_ATOMIC))
+		goto nomem;
+
+	/* Make sure no new addresses are being added during the
+	 * restart.   Do not do this check for COOKIE-WAIT state,
+	 * since there are no peer addresses to check against.
+	 * Upon return an ABORT will have been sent if needed.
+	 */
+	if (!sctp_state(asoc, COOKIE_WAIT)) {
+		if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
+						 commands)) {
+			retval = SCTP_DISPOSITION_CONSUME;
+			goto nomem_retval;
+		}
+	}
+
+	sctp_tietags_populate(new_asoc, asoc);
+
+	/* B) "Z" shall respond immediately with an INIT ACK chunk.  */
+
+	/* If there are errors need to be reported for unknown parameters,
+	 * make sure to reserve enough room in the INIT ACK for them.
+	 */
+	len = 0;
+	if (err_chunk) {
+		len = ntohs(err_chunk->chunk_hdr->length) -
+		      sizeof(struct sctp_chunkhdr);
+	}
+
+	repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
+	if (!repl)
+		goto nomem;
+
+	/* If there are errors need to be reported for unknown parameters,
+	 * include them in the outgoing INIT ACK as "Unrecognized parameter"
+	 * parameter.
+	 */
+	if (err_chunk) {
+		/* Get the "Unrecognized parameter" parameter(s) out of the
+		 * ERROR chunk generated by sctp_verify_init(). Since the
+		 * error cause code for "unknown parameter" and the
+		 * "Unrecognized parameter" type is the same, we can
+		 * construct the parameters in INIT ACK by copying the
+		 * ERROR causes over.
+		 */
+		unk_param = (struct sctp_unrecognized_param *)
+			    ((__u8 *)(err_chunk->chunk_hdr) +
+			    sizeof(struct sctp_chunkhdr));
+		/* Replace the cause code with the "Unrecognized parameter"
+		 * parameter type.
+		 */
+		sctp_addto_chunk(repl, len, unk_param);
+	}
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+
+	/*
+	 * Note: After sending out INIT ACK with the State Cookie parameter,
+	 * "Z" MUST NOT allocate any resources for this new association.
+	 * Otherwise, "Z" will be vulnerable to resource attacks.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
+	retval = SCTP_DISPOSITION_CONSUME;
+
+	return retval;
+
+nomem:
+	retval = SCTP_DISPOSITION_NOMEM;
+nomem_retval:
+	if (new_asoc)
+		sctp_association_free(new_asoc);
+cleanup:
+	if (err_chunk)
+		sctp_chunk_free(err_chunk);
+	return retval;
+}
+
+/*
+ * Handle simultaneous INIT.
+ * This means we started an INIT and then we got an INIT request from
+ * our peer.
+ *
+ * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
+ * This usually indicates an initialization collision, i.e., each
+ * endpoint is attempting, at about the same time, to establish an
+ * association with the other endpoint.
+ *
+ * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
+ * endpoint MUST respond with an INIT ACK using the same parameters it
+ * sent in its original INIT chunk (including its Verification Tag,
+ * unchanged). These original parameters are combined with those from the
+ * newly received INIT chunk. The endpoint shall also generate a State
+ * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
+ * INIT to calculate the State Cookie.
+ *
+ * After that, the endpoint MUST NOT change its state, the T1-init
+ * timer shall be left running and the corresponding TCB MUST NOT be
+ * destroyed. The normal procedures for handling State Cookies when
+ * a TCB exists will resolve the duplicate INITs to a single association.
+ *
+ * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
+ * its Tie-Tags with the Tag information of itself and its peer (see
+ * section 5.2.2 for a description of the Tie-Tags).
+ *
+ * Verification Tag: Not explicit, but an INIT can not have a valid
+ * verification tag, so we skip the check.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_5_2_1_siminit(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* Call helper to do the real work for both simulataneous and
+	 * duplicate INIT chunk handling.
+	 */
+	return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * Handle duplicated INIT messages.  These are usually delayed
+ * restransmissions.
+ *
+ * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
+ * COOKIE-ECHOED and COOKIE-WAIT
+ *
+ * Unless otherwise stated, upon reception of an unexpected INIT for
+ * this association, the endpoint shall generate an INIT ACK with a
+ * State Cookie.  In the outbound INIT ACK the endpoint MUST copy its
+ * current Verification Tag and peer's Verification Tag into a reserved
+ * place within the state cookie.  We shall refer to these locations as
+ * the Peer's-Tie-Tag and the Local-Tie-Tag.  The outbound SCTP packet
+ * containing this INIT ACK MUST carry a Verification Tag value equal to
+ * the Initiation Tag found in the unexpected INIT.  And the INIT ACK
+ * MUST contain a new Initiation Tag (randomly generated see Section
+ * 5.3.1).  Other parameters for the endpoint SHOULD be copied from the
+ * existing parameters of the association (e.g. number of outbound
+ * streams) into the INIT ACK and cookie.
+ *
+ * After sending out the INIT ACK, the endpoint shall take no further
+ * actions, i.e., the existing association, including its current state,
+ * and the corresponding TCB MUST NOT be changed.
+ *
+ * Note: Only when a TCB exists and the association is not in a COOKIE-
+ * WAIT state are the Tie-Tags populated.  For a normal association INIT
+ * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
+ * set to 0 (indicating that no previous TCB existed).  The INIT ACK and
+ * State Cookie are populated as specified in section 5.2.1.
+ *
+ * Verification Tag: Not specified, but an INIT has no way of knowing
+ * what the verification tag could be, so we ignore it.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_5_2_2_dupinit(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* Call helper to do the real work for both simulataneous and
+	 * duplicate INIT chunk handling.
+	 */
+	return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
+}
+
+
+/*
+ * Unexpected INIT-ACK handler.
+ *
+ * Section 5.2.3
+ * If an INIT ACK received by an endpoint in any state other than the
+ * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
+ * An unexpected INIT ACK usually indicates the processing of an old or
+ * duplicated INIT chunk.
+*/
+enum sctp_disposition sctp_sf_do_5_2_3_initack(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* Per the above section, we'll discard the chunk if we have an
+	 * endpoint.  If this is an OOTB INIT-ACK, treat it as such.
+	 */
+	if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
+		return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
+	else
+		return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
+}
+
+/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
+ *
+ * Section 5.2.4
+ *  A)  In this case, the peer may have restarted.
+ */
+static enum sctp_disposition sctp_sf_do_dupcook_a(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					struct sctp_chunk *chunk,
+					struct sctp_cmd_seq *commands,
+					struct sctp_association *new_asoc)
+{
+	struct sctp_init_chunk *peer_init;
+	enum sctp_disposition disposition;
+	struct sctp_ulpevent *ev;
+	struct sctp_chunk *repl;
+	struct sctp_chunk *err;
+
+	/* new_asoc is a brand-new association, so these are not yet
+	 * side effects--it is safe to run them here.
+	 */
+	peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
+
+	if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
+			       GFP_ATOMIC))
+		goto nomem;
+
+	if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
+		goto nomem;
+
+	if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
+		return SCTP_DISPOSITION_DISCARD;
+
+	/* Make sure no new addresses are being added during the
+	 * restart.  Though this is a pretty complicated attack
+	 * since you'd have to get inside the cookie.
+	 */
+	if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
+		return SCTP_DISPOSITION_CONSUME;
+
+	/* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
+	 * the peer has restarted (Action A), it MUST NOT setup a new
+	 * association but instead resend the SHUTDOWN ACK and send an ERROR
+	 * chunk with a "Cookie Received while Shutting Down" error cause to
+	 * its peer.
+	*/
+	if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
+		disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc,
+							 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
+							 chunk, commands);
+		if (SCTP_DISPOSITION_NOMEM == disposition)
+			goto nomem;
+
+		err = sctp_make_op_error(asoc, chunk,
+					 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
+					 NULL, 0, 0);
+		if (err)
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+					SCTP_CHUNK(err));
+
+		return SCTP_DISPOSITION_CONSUME;
+	}
+
+	/* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
+	 * data. Consider the optional choice of resending of this data.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
+	sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
+
+	/* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
+	 * and ASCONF-ACK cache.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
+	sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
+
+	/* Update the content of current association. */
+	if (sctp_assoc_update((struct sctp_association *)asoc, new_asoc)) {
+		struct sctp_chunk *abort;
+
+		abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
+		if (abort) {
+			sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
+		}
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
+		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+				SCTP_PERR(SCTP_ERROR_RSRC_LOW));
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		goto nomem;
+	}
+
+	repl = sctp_make_cookie_ack(asoc, chunk);
+	if (!repl)
+		goto nomem;
+
+	/* Report association restart to upper layer. */
+	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
+					     asoc->c.sinit_num_ostreams,
+					     asoc->c.sinit_max_instreams,
+					     NULL, GFP_ATOMIC);
+	if (!ev)
+		goto nomem_ev;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
+	if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
+	     sctp_state(asoc, SHUTDOWN_SENT)) &&
+	    (sctp_sstate(asoc->base.sk, CLOSING) ||
+	     sock_flag(asoc->base.sk, SOCK_DEAD))) {
+		/* If the socket has been closed by user, don't
+		 * transition to ESTABLISHED. Instead trigger SHUTDOWN
+		 * bundled with COOKIE_ACK.
+		 */
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+		return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
+						     SCTP_ST_CHUNK(0), repl,
+						     commands);
+	} else {
+		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+				SCTP_STATE(SCTP_STATE_ESTABLISHED));
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+	}
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem_ev:
+	sctp_chunk_free(repl);
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
+ *
+ * Section 5.2.4
+ *   B) In this case, both sides may be attempting to start an association
+ *      at about the same time but the peer endpoint started its INIT
+ *      after responding to the local endpoint's INIT
+ */
+/* This case represents an initialization collision.  */
+static enum sctp_disposition sctp_sf_do_dupcook_b(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					struct sctp_chunk *chunk,
+					struct sctp_cmd_seq *commands,
+					struct sctp_association *new_asoc)
+{
+	struct sctp_init_chunk *peer_init;
+	struct sctp_chunk *repl;
+
+	/* new_asoc is a brand-new association, so these are not yet
+	 * side effects--it is safe to run them here.
+	 */
+	peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
+	if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
+			       GFP_ATOMIC))
+		goto nomem;
+
+	if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
+		goto nomem;
+
+	if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
+		return SCTP_DISPOSITION_DISCARD;
+
+	/* Update the content of current association.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_ESTABLISHED));
+	if (asoc->state < SCTP_STATE_ESTABLISHED)
+		SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
+	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
+
+	repl = sctp_make_cookie_ack(new_asoc, chunk);
+	if (!repl)
+		goto nomem;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+
+	/* RFC 2960 5.1 Normal Establishment of an Association
+	 *
+	 * D) IMPLEMENTATION NOTE: An implementation may choose to
+	 * send the Communication Up notification to the SCTP user
+	 * upon reception of a valid COOKIE ECHO chunk.
+	 *
+	 * Sadly, this needs to be implemented as a side-effect, because
+	 * we are not guaranteed to have set the association id of the real
+	 * association and so these notifications need to be delayed until
+	 * the association id is allocated.
+	 */
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
+
+	/* Sockets API Draft Section 5.3.1.6
+	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
+	 * delivers this notification to inform the application that of the
+	 * peers requested adaptation layer.
+	 *
+	 * This also needs to be done as a side effect for the same reason as
+	 * above.
+	 */
+	if (asoc->peer.adaptation_ind)
+		sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
+
+	if (!asoc->peer.auth_capable)
+		sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL());
+
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
+ *
+ * Section 5.2.4
+ *  C) In this case, the local endpoint's cookie has arrived late.
+ *     Before it arrived, the local endpoint sent an INIT and received an
+ *     INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
+ *     but a new tag of its own.
+ */
+/* This case represents an initialization collision.  */
+static enum sctp_disposition sctp_sf_do_dupcook_c(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					struct sctp_chunk *chunk,
+					struct sctp_cmd_seq *commands,
+					struct sctp_association *new_asoc)
+{
+	/* The cookie should be silently discarded.
+	 * The endpoint SHOULD NOT change states and should leave
+	 * any timers running.
+	 */
+	return SCTP_DISPOSITION_DISCARD;
+}
+
+/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
+ *
+ * Section 5.2.4
+ *
+ * D) When both local and remote tags match the endpoint should always
+ *    enter the ESTABLISHED state, if it has not already done so.
+ */
+/* This case represents an initialization collision.  */
+static enum sctp_disposition sctp_sf_do_dupcook_d(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					struct sctp_chunk *chunk,
+					struct sctp_cmd_seq *commands,
+					struct sctp_association *new_asoc)
+{
+	struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
+	struct sctp_chunk *repl;
+
+	/* Clarification from Implementor's Guide:
+	 * D) When both local and remote tags match the endpoint should
+	 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
+	 * It should stop any cookie timer that may be running and send
+	 * a COOKIE ACK.
+	 */
+
+	if (!sctp_auth_chunk_verify(net, chunk, asoc))
+		return SCTP_DISPOSITION_DISCARD;
+
+	/* Don't accidentally move back into established state. */
+	if (asoc->state < SCTP_STATE_ESTABLISHED) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
+		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+				SCTP_STATE(SCTP_STATE_ESTABLISHED));
+		SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
+		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
+				SCTP_NULL());
+
+		/* RFC 2960 5.1 Normal Establishment of an Association
+		 *
+		 * D) IMPLEMENTATION NOTE: An implementation may choose
+		 * to send the Communication Up notification to the
+		 * SCTP user upon reception of a valid COOKIE
+		 * ECHO chunk.
+		 */
+		ev = sctp_ulpevent_make_assoc_change(asoc, 0,
+					     SCTP_COMM_UP, 0,
+					     asoc->c.sinit_num_ostreams,
+					     asoc->c.sinit_max_instreams,
+					     NULL, GFP_ATOMIC);
+		if (!ev)
+			goto nomem;
+
+		/* Sockets API Draft Section 5.3.1.6
+		 * When a peer sends a Adaptation Layer Indication parameter,
+		 * SCTP delivers this notification to inform the application
+		 * that of the peers requested adaptation layer.
+		 */
+		if (asoc->peer.adaptation_ind) {
+			ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
+								 GFP_ATOMIC);
+			if (!ai_ev)
+				goto nomem;
+
+		}
+
+		if (!asoc->peer.auth_capable) {
+			auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
+							     SCTP_AUTH_NO_AUTH,
+							     GFP_ATOMIC);
+			if (!auth_ev)
+				goto nomem;
+		}
+	}
+
+	repl = sctp_make_cookie_ack(asoc, chunk);
+	if (!repl)
+		goto nomem;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+
+	if (ev)
+		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+				SCTP_ULPEVENT(ev));
+	if (ai_ev)
+		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+					SCTP_ULPEVENT(ai_ev));
+	if (auth_ev)
+		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+				SCTP_ULPEVENT(auth_ev));
+
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem:
+	if (auth_ev)
+		sctp_ulpevent_free(auth_ev);
+	if (ai_ev)
+		sctp_ulpevent_free(ai_ev);
+	if (ev)
+		sctp_ulpevent_free(ev);
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Handle a duplicate COOKIE-ECHO.  This usually means a cookie-carrying
+ * chunk was retransmitted and then delayed in the network.
+ *
+ * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
+ *
+ * Verification Tag: None.  Do cookie validation.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_association *new_asoc;
+	struct sctp_chunk *chunk = arg;
+	enum sctp_disposition retval;
+	struct sctp_chunk *err_chk_p;
+	int error = 0;
+	char action;
+
+	/* Make sure that the chunk has a valid length from the protocol
+	 * perspective.  In this case check to make sure we have at least
+	 * enough for the chunk header.  Cookie length verification is
+	 * done later.
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) {
+		if (!sctp_vtag_verify(chunk, asoc))
+			asoc = NULL;
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands);
+	}
+
+	/* "Decode" the chunk.  We have no optional parameters so we
+	 * are in good shape.
+	 */
+	chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
+	if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
+					sizeof(struct sctp_chunkhdr)))
+		goto nomem;
+
+	/* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
+	 * of a duplicate COOKIE ECHO match the Verification Tags of the
+	 * current association, consider the State Cookie valid even if
+	 * the lifespan is exceeded.
+	 */
+	new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
+				      &err_chk_p);
+
+	/* FIXME:
+	 * If the re-build failed, what is the proper error path
+	 * from here?
+	 *
+	 * [We should abort the association. --piggy]
+	 */
+	if (!new_asoc) {
+		/* FIXME: Several errors are possible.  A bad cookie should
+		 * be silently discarded, but think about logging it too.
+		 */
+		switch (error) {
+		case -SCTP_IERROR_NOMEM:
+			goto nomem;
+
+		case -SCTP_IERROR_STALE_COOKIE:
+			sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
+						   err_chk_p);
+			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+		case -SCTP_IERROR_BAD_SIG:
+		default:
+			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+		}
+	}
+
+	/* Update socket peer label if first association. */
+	if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+					chunk->skb)) {
+		sctp_association_free(new_asoc);
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	/* Set temp so that it won't be added into hashtable */
+	new_asoc->temp = 1;
+
+	/* Compare the tie_tag in cookie with the verification tag of
+	 * current association.
+	 */
+	action = sctp_tietags_compare(new_asoc, asoc);
+
+	switch (action) {
+	case 'A': /* Association restart. */
+		retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
+					      new_asoc);
+		break;
+
+	case 'B': /* Collision case B. */
+		retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
+					      new_asoc);
+		break;
+
+	case 'C': /* Collision case C. */
+		retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
+					      new_asoc);
+		break;
+
+	case 'D': /* Collision case D. */
+		retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
+					      new_asoc);
+		break;
+
+	default: /* Discard packet for all others. */
+		retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+		break;
+	}
+
+	/* Delete the tempory new association. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
+	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
+
+	/* Restore association pointer to provide SCTP command interpeter
+	 * with a valid context in case it needs to manipulate
+	 * the queues */
+	sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
+			 SCTP_ASOC((struct sctp_association *)asoc));
+
+	return retval;
+
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Process an ABORT.  (SHUTDOWN-PENDING state)
+ *
+ * See sctp_sf_do_9_1_abort().
+ */
+enum sctp_disposition sctp_sf_shutdown_pending_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+
+	if (!sctp_vtag_verify_either(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the ABORT chunk has a valid length.
+	 * Since this is an ABORT chunk, we have to discard it
+	 * because of the following text:
+	 * RFC 2960, Section 3.3.7
+	 *    If an endpoint receives an ABORT with a format error or for an
+	 *    association that doesn't exist, it MUST silently discard it.
+	 * Because the length is "invalid", we can't really discard just
+	 * as we do not know its true length.  So, to be safe, discard the
+	 * packet.
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* ADD-IP: Special case for ABORT chunks
+	 * F4)  One special consideration is that ABORT Chunks arriving
+	 * destined to the IP address being deleted MUST be
+	 * ignored (see Section 5.3.1 for further details).
+	 */
+	if (SCTP_ADDR_DEL ==
+		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	if (!sctp_err_chunk_valid(chunk))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * Process an ABORT.  (SHUTDOWN-SENT state)
+ *
+ * See sctp_sf_do_9_1_abort().
+ */
+enum sctp_disposition sctp_sf_shutdown_sent_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+
+	if (!sctp_vtag_verify_either(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the ABORT chunk has a valid length.
+	 * Since this is an ABORT chunk, we have to discard it
+	 * because of the following text:
+	 * RFC 2960, Section 3.3.7
+	 *    If an endpoint receives an ABORT with a format error or for an
+	 *    association that doesn't exist, it MUST silently discard it.
+	 * Because the length is "invalid", we can't really discard just
+	 * as we do not know its true length.  So, to be safe, discard the
+	 * packet.
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* ADD-IP: Special case for ABORT chunks
+	 * F4)  One special consideration is that ABORT Chunks arriving
+	 * destined to the IP address being deleted MUST be
+	 * ignored (see Section 5.3.1 for further details).
+	 */
+	if (SCTP_ADDR_DEL ==
+		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	if (!sctp_err_chunk_valid(chunk))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Stop the T2-shutdown timer. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+
+	/* Stop the T5-shutdown guard timer.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
+
+	return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * Process an ABORT.  (SHUTDOWN-ACK-SENT state)
+ *
+ * See sctp_sf_do_9_1_abort().
+ */
+enum sctp_disposition sctp_sf_shutdown_ack_sent_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* The same T2 timer, so we should be able to use
+	 * common function with the SHUTDOWN-SENT state.
+	 */
+	return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * Handle an Error received in COOKIE_ECHOED state.
+ *
+ * Only handle the error type of stale COOKIE Error, the other errors will
+ * be ignored.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_cookie_echoed_err(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_errhdr *err;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the ERROR chunk has a valid length.
+	 * The parameter walking depends on this as well.
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* Process the error here */
+	/* FUTURE FIXME:  When PR-SCTP related and other optional
+	 * parms are emitted, this will have to change to handle multiple
+	 * errors.
+	 */
+	sctp_walk_errors(err, chunk->chunk_hdr) {
+		if (SCTP_ERROR_STALE_COOKIE == err->cause)
+			return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
+							arg, commands);
+	}
+
+	/* It is possible to have malformed error causes, and that
+	 * will cause us to end the walk early.  However, since
+	 * we are discarding the packet, there should be no adverse
+	 * affects.
+	 */
+	return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * Handle a Stale COOKIE Error
+ *
+ * Section: 5.2.6 Handle Stale COOKIE Error
+ * If the association is in the COOKIE-ECHOED state, the endpoint may elect
+ * one of the following three alternatives.
+ * ...
+ * 3) Send a new INIT chunk to the endpoint, adding a Cookie
+ *    Preservative parameter requesting an extension to the lifetime of
+ *    the State Cookie. When calculating the time extension, an
+ *    implementation SHOULD use the RTT information measured based on the
+ *    previous COOKIE ECHO / ERROR exchange, and should add no more
+ *    than 1 second beyond the measured RTT, due to long State Cookie
+ *    lifetimes making the endpoint more subject to a replay attack.
+ *
+ * Verification Tag:  Not explicit, but safe to ignore.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+static enum sctp_disposition sctp_sf_do_5_2_6_stale(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	int attempts = asoc->init_err_counter + 1;
+	struct sctp_chunk *chunk = arg, *reply;
+	struct sctp_cookie_preserve_param bht;
+	struct sctp_bind_addr *bp;
+	struct sctp_errhdr *err;
+	u32 stale;
+
+	if (attempts > asoc->max_init_attempts) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ETIMEDOUT));
+		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
+				SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
+		return SCTP_DISPOSITION_DELETE_TCB;
+	}
+
+	err = (struct sctp_errhdr *)(chunk->skb->data);
+
+	/* When calculating the time extension, an implementation
+	 * SHOULD use the RTT information measured based on the
+	 * previous COOKIE ECHO / ERROR exchange, and should add no
+	 * more than 1 second beyond the measured RTT, due to long
+	 * State Cookie lifetimes making the endpoint more subject to
+	 * a replay attack.
+	 * Measure of Staleness's unit is usec. (1/1000000 sec)
+	 * Suggested Cookie Life-span Increment's unit is msec.
+	 * (1/1000 sec)
+	 * In general, if you use the suggested cookie life, the value
+	 * found in the field of measure of staleness should be doubled
+	 * to give ample time to retransmit the new cookie and thus
+	 * yield a higher probability of success on the reattempt.
+	 */
+	stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
+	stale = (stale * 2) / 1000;
+
+	bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
+	bht.param_hdr.length = htons(sizeof(bht));
+	bht.lifespan_increment = htonl(stale);
+
+	/* Build that new INIT chunk.  */
+	bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
+	reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
+	if (!reply)
+		goto nomem;
+
+	sctp_addto_chunk(reply, sizeof(bht), &bht);
+
+	/* Clear peer's init_tag cached in assoc as we are sending a new INIT */
+	sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
+
+	/* Stop pending T3-rtx and heartbeat timers */
+	sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
+	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
+
+	/* Delete non-primary peer ip addresses since we are transitioning
+	 * back to the COOKIE-WAIT state
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
+
+	/* If we've sent any data bundled with COOKIE-ECHO we will need to
+	 * resend
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
+			SCTP_TRANSPORT(asoc->peer.primary_path));
+
+	/* Cast away the const modifier, as we want to just
+	 * rerun it through as a sideffect.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Process an ABORT.
+ *
+ * Section: 9.1
+ * After checking the Verification Tag, the receiving endpoint shall
+ * remove the association from its record, and shall report the
+ * termination to its upper layer.
+ *
+ * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
+ * B) Rules for packet carrying ABORT:
+ *
+ *  - The endpoint shall always fill in the Verification Tag field of the
+ *    outbound packet with the destination endpoint's tag value if it
+ *    is known.
+ *
+ *  - If the ABORT is sent in response to an OOTB packet, the endpoint
+ *    MUST follow the procedure described in Section 8.4.
+ *
+ *  - The receiver MUST accept the packet if the Verification Tag
+ *    matches either its own tag, OR the tag of its peer. Otherwise, the
+ *    receiver MUST silently discard the packet and take no further
+ *    action.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_9_1_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+
+	if (!sctp_vtag_verify_either(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the ABORT chunk has a valid length.
+	 * Since this is an ABORT chunk, we have to discard it
+	 * because of the following text:
+	 * RFC 2960, Section 3.3.7
+	 *    If an endpoint receives an ABORT with a format error or for an
+	 *    association that doesn't exist, it MUST silently discard it.
+	 * Because the length is "invalid", we can't really discard just
+	 * as we do not know its true length.  So, to be safe, discard the
+	 * packet.
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* ADD-IP: Special case for ABORT chunks
+	 * F4)  One special consideration is that ABORT Chunks arriving
+	 * destined to the IP address being deleted MUST be
+	 * ignored (see Section 5.3.1 for further details).
+	 */
+	if (SCTP_ADDR_DEL ==
+		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	if (!sctp_err_chunk_valid(chunk))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
+}
+
+static enum sctp_disposition __sctp_sf_do_9_1_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	__be16 error = SCTP_ERROR_NO_ERROR;
+	struct sctp_chunk *chunk = arg;
+	unsigned int len;
+
+	/* See if we have an error cause code in the chunk.  */
+	len = ntohs(chunk->chunk_hdr->length);
+	if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
+		error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
+	/* ASSOC_FAILED will DELETE_TCB. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
+	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+
+	return SCTP_DISPOSITION_ABORT;
+}
+
+/*
+ * Process an ABORT.  (COOKIE-WAIT state)
+ *
+ * See sctp_sf_do_9_1_abort() above.
+ */
+enum sctp_disposition sctp_sf_cookie_wait_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	__be16 error = SCTP_ERROR_NO_ERROR;
+	struct sctp_chunk *chunk = arg;
+	unsigned int len;
+
+	if (!sctp_vtag_verify_either(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the ABORT chunk has a valid length.
+	 * Since this is an ABORT chunk, we have to discard it
+	 * because of the following text:
+	 * RFC 2960, Section 3.3.7
+	 *    If an endpoint receives an ABORT with a format error or for an
+	 *    association that doesn't exist, it MUST silently discard it.
+	 * Because the length is "invalid", we can't really discard just
+	 * as we do not know its true length.  So, to be safe, discard the
+	 * packet.
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* See if we have an error cause code in the chunk.  */
+	len = ntohs(chunk->chunk_hdr->length);
+	if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
+		error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
+
+	return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
+				      chunk->transport);
+}
+
+/*
+ * Process an incoming ICMP as an ABORT.  (COOKIE-WAIT state)
+ */
+enum sctp_disposition sctp_sf_cookie_wait_icmp_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
+				      ENOPROTOOPT, asoc,
+				      (struct sctp_transport *)arg);
+}
+
+/*
+ * Process an ABORT.  (COOKIE-ECHOED state)
+ */
+enum sctp_disposition sctp_sf_cookie_echoed_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* There is a single T1 timer, so we should be able to use
+	 * common function with the COOKIE-WAIT state.
+	 */
+	return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * Stop T1 timer and abort association with "INIT failed".
+ *
+ * This is common code called by several sctp_sf_*_abort() functions above.
+ */
+static enum sctp_disposition sctp_stop_t1_and_abort(
+					struct net *net,
+					struct sctp_cmd_seq *commands,
+					__be16 error, int sk_err,
+					const struct sctp_association *asoc,
+					struct sctp_transport *transport)
+{
+	pr_debug("%s: ABORT received (INIT)\n", __func__);
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_CLOSED));
+	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
+	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
+	/* CMD_INIT_FAILED will DELETE_TCB. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
+			SCTP_PERR(error));
+
+	return SCTP_DISPOSITION_ABORT;
+}
+
+/*
+ * sctp_sf_do_9_2_shut
+ *
+ * Section: 9.2
+ * Upon the reception of the SHUTDOWN, the peer endpoint shall
+ *  - enter the SHUTDOWN-RECEIVED state,
+ *
+ *  - stop accepting new data from its SCTP user
+ *
+ *  - verify, by checking the Cumulative TSN Ack field of the chunk,
+ *    that all its outstanding DATA chunks have been received by the
+ *    SHUTDOWN sender.
+ *
+ * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
+ * send a SHUTDOWN in response to a ULP request. And should discard
+ * subsequent SHUTDOWN chunks.
+ *
+ * If there are still outstanding DATA chunks left, the SHUTDOWN
+ * receiver shall continue to follow normal data transmission
+ * procedures defined in Section 6 until all outstanding DATA chunks
+ * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
+ * new data from its SCTP user.
+ *
+ * Verification Tag:  8.5 Verification Tag [Normal verification]
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_9_2_shutdown(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	enum sctp_disposition disposition;
+	struct sctp_chunk *chunk = arg;
+	struct sctp_shutdownhdr *sdh;
+	struct sctp_ulpevent *ev;
+	__u32 ctsn;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the SHUTDOWN chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* Convert the elaborate header.  */
+	sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
+	skb_pull(chunk->skb, sizeof(*sdh));
+	chunk->subh.shutdown_hdr = sdh;
+	ctsn = ntohl(sdh->cum_tsn_ack);
+
+	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
+		pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
+			 asoc->ctsn_ack_point);
+
+		return SCTP_DISPOSITION_DISCARD;
+	}
+
+	/* If Cumulative TSN Ack beyond the max tsn currently
+	 * send, terminating the association and respond to the
+	 * sender with an ABORT.
+	 */
+	if (!TSN_lt(ctsn, asoc->next_tsn))
+		return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
+
+	/* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
+	 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
+	 * inform the application that it should cease sending data.
+	 */
+	ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
+	if (!ev) {
+		disposition = SCTP_DISPOSITION_NOMEM;
+		goto out;
+	}
+	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
+
+	/* Upon the reception of the SHUTDOWN, the peer endpoint shall
+	 *  - enter the SHUTDOWN-RECEIVED state,
+	 *  - stop accepting new data from its SCTP user
+	 *
+	 * [This is implicit in the new state.]
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
+	disposition = SCTP_DISPOSITION_CONSUME;
+
+	if (sctp_outq_is_empty(&asoc->outqueue)) {
+		disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
+							  arg, commands);
+	}
+
+	if (SCTP_DISPOSITION_NOMEM == disposition)
+		goto out;
+
+	/*  - verify, by checking the Cumulative TSN Ack field of the
+	 *    chunk, that all its outstanding DATA chunks have been
+	 *    received by the SHUTDOWN sender.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
+			SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
+
+out:
+	return disposition;
+}
+
+/*
+ * sctp_sf_do_9_2_shut_ctsn
+ *
+ * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
+ * it MUST NOT send a SHUTDOWN in response to a ULP request.
+ * The Cumulative TSN Ack of the received SHUTDOWN chunk
+ * MUST be processed.
+ */
+enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_shutdownhdr *sdh;
+	__u32 ctsn;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the SHUTDOWN chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
+	ctsn = ntohl(sdh->cum_tsn_ack);
+
+	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
+		pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
+			 asoc->ctsn_ack_point);
+
+		return SCTP_DISPOSITION_DISCARD;
+	}
+
+	/* If Cumulative TSN Ack beyond the max tsn currently
+	 * send, terminating the association and respond to the
+	 * sender with an ABORT.
+	 */
+	if (!TSN_lt(ctsn, asoc->next_tsn))
+		return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
+
+	/* verify, by checking the Cumulative TSN Ack field of the
+	 * chunk, that all its outstanding DATA chunks have been
+	 * received by the SHUTDOWN sender.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
+			SCTP_BE32(sdh->cum_tsn_ack));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/* RFC 2960 9.2
+ * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
+ * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
+ * transport addresses (either in the IP addresses or in the INIT chunk)
+ * that belong to this association, it should discard the INIT chunk and
+ * retransmit the SHUTDOWN ACK chunk.
+ */
+static enum sctp_disposition
+__sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
+			   const struct sctp_association *asoc,
+			   const union sctp_subtype type, void *arg,
+			   struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_chunk *reply;
+
+	/* Make sure that the chunk has a valid length */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* Since we are not going to really process this INIT, there
+	 * is no point in verifying chunk boundries.  Just generate
+	 * the SHUTDOWN ACK.
+	 */
+	reply = sctp_make_shutdown_ack(asoc, chunk);
+	if (NULL == reply)
+		goto nomem;
+
+	/* Set the transport for the SHUTDOWN ACK chunk and the timeout for
+	 * the T2-SHUTDOWN timer.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
+
+	/* and restart the T2-shutdown timer. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+
+	return SCTP_DISPOSITION_CONSUME;
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+enum sctp_disposition
+sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
+			 const struct sctp_association *asoc,
+			 const union sctp_subtype type, void *arg,
+			 struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+
+	if (!chunk->singleton)
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	if (chunk->sctp_hdr->vtag != 0)
+		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
+
+	return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * sctp_sf_do_ecn_cwr
+ *
+ * Section:  Appendix A: Explicit Congestion Notification
+ *
+ * CWR:
+ *
+ * RFC 2481 details a specific bit for a sender to send in the header of
+ * its next outbound TCP segment to indicate to its peer that it has
+ * reduced its congestion window.  This is termed the CWR bit.  For
+ * SCTP the same indication is made by including the CWR chunk.
+ * This chunk contains one data element, i.e. the TSN number that
+ * was sent in the ECNE chunk.  This element represents the lowest
+ * TSN number in the datagram that was originally marked with the
+ * CE bit.
+ *
+ * Verification Tag: 8.5 Verification Tag [Normal verification]
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net,
+					 const struct sctp_endpoint *ep,
+					 const struct sctp_association *asoc,
+					 const union sctp_subtype type,
+					 void *arg,
+					 struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_cwrhdr *cwr;
+	u32 lowest_tsn;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	cwr = (struct sctp_cwrhdr *)chunk->skb->data;
+	skb_pull(chunk->skb, sizeof(*cwr));
+
+	lowest_tsn = ntohl(cwr->lowest_tsn);
+
+	/* Does this CWR ack the last sent congestion notification? */
+	if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
+		/* Stop sending ECNE. */
+		sctp_add_cmd_sf(commands,
+				SCTP_CMD_ECN_CWR,
+				SCTP_U32(lowest_tsn));
+	}
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * sctp_sf_do_ecne
+ *
+ * Section:  Appendix A: Explicit Congestion Notification
+ *
+ * ECN-Echo
+ *
+ * RFC 2481 details a specific bit for a receiver to send back in its
+ * TCP acknowledgements to notify the sender of the Congestion
+ * Experienced (CE) bit having arrived from the network.  For SCTP this
+ * same indication is made by including the ECNE chunk.  This chunk
+ * contains one data element, i.e. the lowest TSN associated with the IP
+ * datagram marked with the CE bit.....
+ *
+ * Verification Tag: 8.5 Verification Tag [Normal verification]
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_ecne(struct net *net,
+				      const struct sctp_endpoint *ep,
+				      const struct sctp_association *asoc,
+				      const union sctp_subtype type,
+				      void *arg, struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_ecnehdr *ecne;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	ecne = (struct sctp_ecnehdr *)chunk->skb->data;
+	skb_pull(chunk->skb, sizeof(*ecne));
+
+	/* If this is a newer ECNE than the last CWR packet we sent out */
+	sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
+			SCTP_U32(ntohl(ecne->lowest_tsn)));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Section: 6.2  Acknowledgement on Reception of DATA Chunks
+ *
+ * The SCTP endpoint MUST always acknowledge the reception of each valid
+ * DATA chunk.
+ *
+ * The guidelines on delayed acknowledgement algorithm specified in
+ * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
+ * acknowledgement SHOULD be generated for at least every second packet
+ * (not every second DATA chunk) received, and SHOULD be generated within
+ * 200 ms of the arrival of any unacknowledged DATA chunk. In some
+ * situations it may be beneficial for an SCTP transmitter to be more
+ * conservative than the algorithms detailed in this document allow.
+ * However, an SCTP transmitter MUST NOT be more aggressive than the
+ * following algorithms allow.
+ *
+ * A SCTP receiver MUST NOT generate more than one SACK for every
+ * incoming packet, other than to update the offered window as the
+ * receiving application consumes new data.
+ *
+ * Verification Tag:  8.5 Verification Tag [Normal verification]
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	union sctp_arg force = SCTP_NOFORCE();
+	struct sctp_chunk *chunk = arg;
+	int error;
+
+	if (!sctp_vtag_verify(chunk, asoc)) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
+				SCTP_NULL());
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	error = sctp_eat_data(asoc, chunk, commands);
+	switch (error) {
+	case SCTP_IERROR_NO_ERROR:
+		break;
+	case SCTP_IERROR_HIGH_TSN:
+	case SCTP_IERROR_BAD_STREAM:
+		SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
+		goto discard_noforce;
+	case SCTP_IERROR_DUP_TSN:
+	case SCTP_IERROR_IGNORE_TSN:
+		SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
+		goto discard_force;
+	case SCTP_IERROR_NO_DATA:
+		return SCTP_DISPOSITION_ABORT;
+	case SCTP_IERROR_PROTO_VIOLATION:
+		return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
+					       (u8 *)chunk->subh.data_hdr,
+					       sctp_datahdr_len(&asoc->stream));
+	default:
+		BUG();
+	}
+
+	if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
+		force = SCTP_FORCE();
+
+	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
+	}
+
+	/* If this is the last chunk in a packet, we need to count it
+	 * toward sack generation.  Note that we need to SACK every
+	 * OTHER packet containing data chunks, EVEN IF WE DISCARD
+	 * THEM.  We elect to NOT generate SACK's if the chunk fails
+	 * the verification tag test.
+	 *
+	 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
+	 *
+	 * The SCTP endpoint MUST always acknowledge the reception of
+	 * each valid DATA chunk.
+	 *
+	 * The guidelines on delayed acknowledgement algorithm
+	 * specified in  Section 4.2 of [RFC2581] SHOULD be followed.
+	 * Specifically, an acknowledgement SHOULD be generated for at
+	 * least every second packet (not every second DATA chunk)
+	 * received, and SHOULD be generated within 200 ms of the
+	 * arrival of any unacknowledged DATA chunk.  In some
+	 * situations it may be beneficial for an SCTP transmitter to
+	 * be more conservative than the algorithms detailed in this
+	 * document allow. However, an SCTP transmitter MUST NOT be
+	 * more aggressive than the following algorithms allow.
+	 */
+	if (chunk->end_of_packet)
+		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
+
+	return SCTP_DISPOSITION_CONSUME;
+
+discard_force:
+	/* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
+	 *
+	 * When a packet arrives with duplicate DATA chunk(s) and with
+	 * no new DATA chunk(s), the endpoint MUST immediately send a
+	 * SACK with no delay.  If a packet arrives with duplicate
+	 * DATA chunk(s) bundled with new DATA chunks, the endpoint
+	 * MAY immediately send a SACK.  Normally receipt of duplicate
+	 * DATA chunks will occur when the original SACK chunk was lost
+	 * and the peer's RTO has expired.  The duplicate TSN number(s)
+	 * SHOULD be reported in the SACK as duplicate.
+	 */
+	/* In our case, we split the MAY SACK advice up whether or not
+	 * the last chunk is a duplicate.'
+	 */
+	if (chunk->end_of_packet)
+		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
+	return SCTP_DISPOSITION_DISCARD;
+
+discard_noforce:
+	if (chunk->end_of_packet)
+		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
+
+	return SCTP_DISPOSITION_DISCARD;
+}
+
+/*
+ * sctp_sf_eat_data_fast_4_4
+ *
+ * Section: 4 (4)
+ * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
+ *    DATA chunks without delay.
+ *
+ * Verification Tag:  8.5 Verification Tag [Normal verification]
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_eat_data_fast_4_4(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	int error;
+
+	if (!sctp_vtag_verify(chunk, asoc)) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
+				SCTP_NULL());
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	error = sctp_eat_data(asoc, chunk, commands);
+	switch (error) {
+	case SCTP_IERROR_NO_ERROR:
+	case SCTP_IERROR_HIGH_TSN:
+	case SCTP_IERROR_DUP_TSN:
+	case SCTP_IERROR_IGNORE_TSN:
+	case SCTP_IERROR_BAD_STREAM:
+		break;
+	case SCTP_IERROR_NO_DATA:
+		return SCTP_DISPOSITION_ABORT;
+	case SCTP_IERROR_PROTO_VIOLATION:
+		return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
+					       (u8 *)chunk->subh.data_hdr,
+					       sctp_datahdr_len(&asoc->stream));
+	default:
+		BUG();
+	}
+
+	/* Go a head and force a SACK, since we are shutting down. */
+
+	/* Implementor's Guide.
+	 *
+	 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
+	 * respond to each received packet containing one or more DATA chunk(s)
+	 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
+	 */
+	if (chunk->end_of_packet) {
+		/* We must delay the chunk creation since the cumulative
+		 * TSN has not been updated yet.
+		 */
+		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
+		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+	}
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Section: 6.2  Processing a Received SACK
+ * D) Any time a SACK arrives, the endpoint performs the following:
+ *
+ *     i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
+ *     then drop the SACK.   Since Cumulative TSN Ack is monotonically
+ *     increasing, a SACK whose Cumulative TSN Ack is less than the
+ *     Cumulative TSN Ack Point indicates an out-of-order SACK.
+ *
+ *     ii) Set rwnd equal to the newly received a_rwnd minus the number
+ *     of bytes still outstanding after processing the Cumulative TSN Ack
+ *     and the Gap Ack Blocks.
+ *
+ *     iii) If the SACK is missing a TSN that was previously
+ *     acknowledged via a Gap Ack Block (e.g., the data receiver
+ *     reneged on the data), then mark the corresponding DATA chunk
+ *     as available for retransmit:  Mark it as missing for fast
+ *     retransmit as described in Section 7.2.4 and if no retransmit
+ *     timer is running for the destination address to which the DATA
+ *     chunk was originally transmitted, then T3-rtx is started for
+ *     that destination address.
+ *
+ * Verification Tag:  8.5 Verification Tag [Normal verification]
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_sackhdr *sackh;
+	__u32 ctsn;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the SACK chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* Pull the SACK chunk from the data buffer */
+	sackh = sctp_sm_pull_sack(chunk);
+	/* Was this a bogus SACK? */
+	if (!sackh)
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	chunk->subh.sack_hdr = sackh;
+	ctsn = ntohl(sackh->cum_tsn_ack);
+
+	/* If Cumulative TSN Ack beyond the max tsn currently
+	 * send, terminating the association and respond to the
+	 * sender with an ABORT.
+	 */
+	if (TSN_lte(asoc->next_tsn, ctsn))
+		return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
+
+	trace_sctp_probe(ep, asoc, chunk);
+
+	/* i) If Cumulative TSN Ack is less than the Cumulative TSN
+	 *     Ack Point, then drop the SACK.  Since Cumulative TSN
+	 *     Ack is monotonically increasing, a SACK whose
+	 *     Cumulative TSN Ack is less than the Cumulative TSN Ack
+	 *     Point indicates an out-of-order SACK.
+	 */
+	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
+		pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
+			 asoc->ctsn_ack_point);
+
+		return SCTP_DISPOSITION_DISCARD;
+	}
+
+	/* Return this SACK for further processing.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
+
+	/* Note: We do the rest of the work on the PROCESS_SACK
+	 * sideeffect.
+	 */
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Generate an ABORT in response to a packet.
+ *
+ * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
+ *
+ * 8) The receiver should respond to the sender of the OOTB packet with
+ *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
+ *    MUST fill in the Verification Tag field of the outbound packet
+ *    with the value found in the Verification Tag field of the OOTB
+ *    packet and set the T-bit in the Chunk Flags to indicate that the
+ *    Verification Tag is reflected.  After sending this ABORT, the
+ *    receiver of the OOTB packet shall discard the OOTB packet and take
+ *    no further action.
+ *
+ * Verification Tag:
+ *
+ * The return value is the disposition of the chunk.
+*/
+static enum sctp_disposition sctp_sf_tabort_8_4_8(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_packet *packet = NULL;
+	struct sctp_chunk *chunk = arg;
+	struct sctp_chunk *abort;
+
+	packet = sctp_ootb_pkt_new(net, asoc, chunk);
+	if (!packet)
+		return SCTP_DISPOSITION_NOMEM;
+
+	/* Make an ABORT. The T bit will be set if the asoc
+	 * is NULL.
+	 */
+	abort = sctp_make_abort(asoc, chunk, 0);
+	if (!abort) {
+		sctp_ootb_pkt_free(packet);
+		return SCTP_DISPOSITION_NOMEM;
+	}
+
+	/* Reflect vtag if T-Bit is set */
+	if (sctp_test_T_bit(abort))
+		packet->vtag = ntohl(chunk->sctp_hdr->vtag);
+
+	/* Set the skb to the belonging sock for accounting.  */
+	abort->skb->sk = ep->base.sk;
+
+	sctp_packet_append_chunk(packet, abort);
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
+			SCTP_PACKET(packet));
+
+	SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+
+	sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Received an ERROR chunk from peer.  Generate SCTP_REMOTE_ERROR
+ * event as ULP notification for each cause included in the chunk.
+ *
+ * API 5.3.1.3 - SCTP_REMOTE_ERROR
+ *
+ * The return value is the disposition of the chunk.
+*/
+enum sctp_disposition sctp_sf_operr_notify(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_errhdr *err;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the ERROR chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+	sctp_walk_errors(err, chunk->chunk_hdr);
+	if ((void *)err != (void *)chunk->chunk_end)
+		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
+						  (void *)err, commands);
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
+			SCTP_CHUNK(chunk));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Process an inbound SHUTDOWN ACK.
+ *
+ * From Section 9.2:
+ * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
+ * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
+ * peer, and remove all record of the association.
+ *
+ * The return value is the disposition.
+ */
+enum sctp_disposition sctp_sf_do_9_2_final(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_chunk *reply;
+	struct sctp_ulpevent *ev;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+	/* 10.2 H) SHUTDOWN COMPLETE notification
+	 *
+	 * When SCTP completes the shutdown procedures (section 9.2) this
+	 * notification is passed to the upper layer.
+	 */
+	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
+					     0, 0, 0, NULL, GFP_ATOMIC);
+	if (!ev)
+		goto nomem;
+
+	/* ...send a SHUTDOWN COMPLETE chunk to its peer, */
+	reply = sctp_make_shutdown_complete(asoc, chunk);
+	if (!reply)
+		goto nomem_chunk;
+
+	/* Do all the commands now (after allocation), so that we
+	 * have consistent state if memory allocation failes
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
+
+	/* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
+	 * stop the T2-shutdown timer,
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_CLOSED));
+	SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
+	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+
+	/* ...and remove all record of the association. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
+	return SCTP_DISPOSITION_DELETE_TCB;
+
+nomem_chunk:
+	sctp_ulpevent_free(ev);
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
+ *
+ * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
+ *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
+ *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
+ *    packet must fill in the Verification Tag field of the outbound
+ *    packet with the Verification Tag received in the SHUTDOWN ACK and
+ *    set the T-bit in the Chunk Flags to indicate that the Verification
+ *    Tag is reflected.
+ *
+ * 8) The receiver should respond to the sender of the OOTB packet with
+ *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
+ *    MUST fill in the Verification Tag field of the outbound packet
+ *    with the value found in the Verification Tag field of the OOTB
+ *    packet and set the T-bit in the Chunk Flags to indicate that the
+ *    Verification Tag is reflected.  After sending this ABORT, the
+ *    receiver of the OOTB packet shall discard the OOTB packet and take
+ *    no further action.
+ */
+enum sctp_disposition sctp_sf_ootb(struct net *net,
+				   const struct sctp_endpoint *ep,
+				   const struct sctp_association *asoc,
+				   const union sctp_subtype type,
+				   void *arg, struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sk_buff *skb = chunk->skb;
+	struct sctp_chunkhdr *ch;
+	struct sctp_errhdr *err;
+	int ootb_cookie_ack = 0;
+	int ootb_shut_ack = 0;
+	__u8 *ch_end;
+
+	SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
+
+	if (asoc && !sctp_vtag_verify(chunk, asoc))
+		asoc = NULL;
+
+	ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
+	do {
+		/* Report violation if the chunk is less then minimal */
+		if (ntohs(ch->length) < sizeof(*ch))
+			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+		/* Report violation if chunk len overflows */
+		ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
+		if (ch_end > skb_tail_pointer(skb))
+			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+		/* Now that we know we at least have a chunk header,
+		 * do things that are type appropriate.
+		 */
+		if (SCTP_CID_SHUTDOWN_ACK == ch->type)
+			ootb_shut_ack = 1;
+
+		/* RFC 2960, Section 3.3.7
+		 *   Moreover, under any circumstances, an endpoint that
+		 *   receives an ABORT  MUST NOT respond to that ABORT by
+		 *   sending an ABORT of its own.
+		 */
+		if (SCTP_CID_ABORT == ch->type)
+			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+		/* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
+		 * or a COOKIE ACK the SCTP Packet should be silently
+		 * discarded.
+		 */
+
+		if (SCTP_CID_COOKIE_ACK == ch->type)
+			ootb_cookie_ack = 1;
+
+		if (SCTP_CID_ERROR == ch->type) {
+			sctp_walk_errors(err, ch) {
+				if (SCTP_ERROR_STALE_COOKIE == err->cause) {
+					ootb_cookie_ack = 1;
+					break;
+				}
+			}
+		}
+
+		ch = (struct sctp_chunkhdr *)ch_end;
+	} while (ch_end < skb_tail_pointer(skb));
+
+	if (ootb_shut_ack)
+		return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
+	else if (ootb_cookie_ack)
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	else
+		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * Handle an "Out of the blue" SHUTDOWN ACK.
+ *
+ * Section: 8.4 5, sctpimpguide 2.41.
+ *
+ * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
+ *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
+ *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
+ *    packet must fill in the Verification Tag field of the outbound
+ *    packet with the Verification Tag received in the SHUTDOWN ACK and
+ *    set the T-bit in the Chunk Flags to indicate that the Verification
+ *    Tag is reflected.
+ *
+ * Inputs
+ * (endpoint, asoc, type, arg, commands)
+ *
+ * Outputs
+ * (enum sctp_disposition)
+ *
+ * The return value is the disposition of the chunk.
+ */
+static enum sctp_disposition sctp_sf_shut_8_4_5(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_packet *packet = NULL;
+	struct sctp_chunk *chunk = arg;
+	struct sctp_chunk *shut;
+
+	packet = sctp_ootb_pkt_new(net, asoc, chunk);
+	if (!packet)
+		return SCTP_DISPOSITION_NOMEM;
+
+	/* Make an SHUTDOWN_COMPLETE.
+	 * The T bit will be set if the asoc is NULL.
+	 */
+	shut = sctp_make_shutdown_complete(asoc, chunk);
+	if (!shut) {
+		sctp_ootb_pkt_free(packet);
+		return SCTP_DISPOSITION_NOMEM;
+	}
+
+	/* Reflect vtag if T-Bit is set */
+	if (sctp_test_T_bit(shut))
+		packet->vtag = ntohl(chunk->sctp_hdr->vtag);
+
+	/* Set the skb to the belonging sock for accounting.  */
+	shut->skb->sk = ep->base.sk;
+
+	sctp_packet_append_chunk(packet, shut);
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
+			SCTP_PACKET(packet));
+
+	SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+
+	/* We need to discard the rest of the packet to prevent
+	 * potential bomming attacks from additional bundled chunks.
+	 * This is documented in SCTP Threats ID.
+	 */
+	return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
+ *
+ * Verification Tag:  8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
+ *   If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
+ *   procedures in section 8.4 SHOULD be followed, in other words it
+ *   should be treated as an Out Of The Blue packet.
+ *   [This means that we do NOT check the Verification Tag on these
+ *   chunks. --piggy ]
+ *
+ */
+enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net,
+					    const struct sctp_endpoint *ep,
+					    const struct sctp_association *asoc,
+					    const union sctp_subtype type,
+					    void *arg,
+					    struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		asoc = NULL;
+
+	/* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* Although we do have an association in this case, it corresponds
+	 * to a restarted association. So the packet is treated as an OOTB
+	 * packet and the state function that handles OOTB SHUTDOWN_ACK is
+	 * called with a NULL association.
+	 */
+	SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
+
+	return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
+}
+
+/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.  */
+enum sctp_disposition sctp_sf_do_asconf(struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_paramhdr *err_param = NULL;
+	struct sctp_chunk *asconf_ack = NULL;
+	struct sctp_chunk *chunk = arg;
+	struct sctp_addiphdr *hdr;
+	__u32 serial;
+
+	if (!sctp_vtag_verify(chunk, asoc)) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
+				SCTP_NULL());
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	/* Make sure that the ASCONF ADDIP chunk has a valid length.  */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* ADD-IP: Section 4.1.1
+	 * This chunk MUST be sent in an authenticated way by using
+	 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
+	 * is received unauthenticated it MUST be silently discarded as
+	 * described in [I-D.ietf-tsvwg-sctp-auth].
+	 */
+	if (!asoc->peer.asconf_capable ||
+	    (!net->sctp.addip_noauth && !chunk->auth))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	hdr = (struct sctp_addiphdr *)chunk->skb->data;
+	serial = ntohl(hdr->serial);
+
+	/* Verify the ASCONF chunk before processing it. */
+	if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
+		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
+						  (void *)err_param, commands);
+
+	/* ADDIP 5.2 E1) Compare the value of the serial number to the value
+	 * the endpoint stored in a new association variable
+	 * 'Peer-Serial-Number'.
+	 */
+	if (serial == asoc->peer.addip_serial + 1) {
+		/* If this is the first instance of ASCONF in the packet,
+		 * we can clean our old ASCONF-ACKs.
+		 */
+		if (!chunk->has_asconf)
+			sctp_assoc_clean_asconf_ack_cache(asoc);
+
+		/* ADDIP 5.2 E4) When the Sequence Number matches the next one
+		 * expected, process the ASCONF as described below and after
+		 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
+		 * the response packet and cache a copy of it (in the event it
+		 * later needs to be retransmitted).
+		 *
+		 * Essentially, do V1-V5.
+		 */
+		asconf_ack = sctp_process_asconf((struct sctp_association *)
+						 asoc, chunk);
+		if (!asconf_ack)
+			return SCTP_DISPOSITION_NOMEM;
+	} else if (serial < asoc->peer.addip_serial + 1) {
+		/* ADDIP 5.2 E2)
+		 * If the value found in the Sequence Number is less than the
+		 * ('Peer- Sequence-Number' + 1), simply skip to the next
+		 * ASCONF, and include in the outbound response packet
+		 * any previously cached ASCONF-ACK response that was
+		 * sent and saved that matches the Sequence Number of the
+		 * ASCONF.  Note: It is possible that no cached ASCONF-ACK
+		 * Chunk exists.  This will occur when an older ASCONF
+		 * arrives out of order.  In such a case, the receiver
+		 * should skip the ASCONF Chunk and not include ASCONF-ACK
+		 * Chunk for that chunk.
+		 */
+		asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
+		if (!asconf_ack)
+			return SCTP_DISPOSITION_DISCARD;
+
+		/* Reset the transport so that we select the correct one
+		 * this time around.  This is to make sure that we don't
+		 * accidentally use a stale transport that's been removed.
+		 */
+		asconf_ack->transport = NULL;
+	} else {
+		/* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
+		 * it must be either a stale packet or from an attacker.
+		 */
+		return SCTP_DISPOSITION_DISCARD;
+	}
+
+	/* ADDIP 5.2 E6)  The destination address of the SCTP packet
+	 * containing the ASCONF-ACK Chunks MUST be the source address of
+	 * the SCTP packet that held the ASCONF Chunks.
+	 *
+	 * To do this properly, we'll set the destination address of the chunk
+	 * and at the transmit time, will try look up the transport to use.
+	 * Since ASCONFs may be bundled, the correct transport may not be
+	 * created until we process the entire packet, thus this workaround.
+	 */
+	asconf_ack->dest = chunk->source;
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
+	if (asoc->new_transport) {
+		sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
+		((struct sctp_association *)asoc)->new_transport = NULL;
+	}
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+static enum sctp_disposition sctp_send_next_asconf(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					struct sctp_association *asoc,
+					const union sctp_subtype type,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *asconf;
+	struct list_head *entry;
+
+	if (list_empty(&asoc->addip_chunk_list))
+		return SCTP_DISPOSITION_CONSUME;
+
+	entry = asoc->addip_chunk_list.next;
+	asconf = list_entry(entry, struct sctp_chunk, list);
+
+	list_del_init(entry);
+	sctp_chunk_hold(asconf);
+	asoc->addip_last_asconf = asconf;
+
+	return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
+}
+
+/*
+ * ADDIP Section 4.3 General rules for address manipulation
+ * When building TLV parameters for the ASCONF Chunk that will add or
+ * delete IP addresses the D0 to D13 rules should be applied:
+ */
+enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
+					    const struct sctp_endpoint *ep,
+					    const struct sctp_association *asoc,
+					    const union sctp_subtype type,
+					    void *arg,
+					    struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
+	struct sctp_paramhdr *err_param = NULL;
+	struct sctp_chunk *asconf_ack = arg;
+	struct sctp_addiphdr *addip_hdr;
+	__u32 sent_serial, rcvd_serial;
+	struct sctp_chunk *abort;
+
+	if (!sctp_vtag_verify(asconf_ack, asoc)) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
+				SCTP_NULL());
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	/* Make sure that the ADDIP chunk has a valid length.  */
+	if (!sctp_chunk_length_valid(asconf_ack,
+				     sizeof(struct sctp_addip_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	/* ADD-IP, Section 4.1.2:
+	 * This chunk MUST be sent in an authenticated way by using
+	 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
+	 * is received unauthenticated it MUST be silently discarded as
+	 * described in [I-D.ietf-tsvwg-sctp-auth].
+	 */
+	if (!asoc->peer.asconf_capable ||
+	    (!net->sctp.addip_noauth && !asconf_ack->auth))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
+	rcvd_serial = ntohl(addip_hdr->serial);
+
+	/* Verify the ASCONF-ACK chunk before processing it. */
+	if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
+		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
+			   (void *)err_param, commands);
+
+	if (last_asconf) {
+		addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr;
+		sent_serial = ntohl(addip_hdr->serial);
+	} else {
+		sent_serial = asoc->addip_serial - 1;
+	}
+
+	/* D0) If an endpoint receives an ASCONF-ACK that is greater than or
+	 * equal to the next serial number to be used but no ASCONF chunk is
+	 * outstanding the endpoint MUST ABORT the association. Note that a
+	 * sequence number is greater than if it is no more than 2^^31-1
+	 * larger than the current sequence number (using serial arithmetic).
+	 */
+	if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
+	    !(asoc->addip_last_asconf)) {
+		abort = sctp_make_abort(asoc, asconf_ack,
+					sizeof(struct sctp_errhdr));
+		if (abort) {
+			sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+					SCTP_CHUNK(abort));
+		}
+		/* We are going to ABORT, so we might as well stop
+		 * processing the rest of the chunks in the packet.
+		 */
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
+		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ECONNABORTED));
+		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+				SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		return SCTP_DISPOSITION_ABORT;
+	}
+
+	if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
+
+		if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
+					     asconf_ack))
+			return sctp_send_next_asconf(net, ep,
+					(struct sctp_association *)asoc,
+							type, commands);
+
+		abort = sctp_make_abort(asoc, asconf_ack,
+					sizeof(struct sctp_errhdr));
+		if (abort) {
+			sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+					SCTP_CHUNK(abort));
+		}
+		/* We are going to ABORT, so we might as well stop
+		 * processing the rest of the chunks in the packet.
+		 */
+		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ECONNABORTED));
+		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+				SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		return SCTP_DISPOSITION_ABORT;
+	}
+
+	return SCTP_DISPOSITION_DISCARD;
+}
+
+/* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */
+enum sctp_disposition sctp_sf_do_reconf(struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_paramhdr *err_param = NULL;
+	struct sctp_chunk *chunk = arg;
+	struct sctp_reconf_chunk *hdr;
+	union sctp_params param;
+
+	if (!sctp_vtag_verify(chunk, asoc)) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
+				SCTP_NULL());
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	/* Make sure that the RECONF chunk has a valid length.  */
+	if (!sctp_chunk_length_valid(chunk, sizeof(*hdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	if (!sctp_verify_reconf(asoc, chunk, &err_param))
+		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
+						  (void *)err_param, commands);
+
+	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
+	sctp_walk_params(param, hdr, params) {
+		struct sctp_chunk *reply = NULL;
+		struct sctp_ulpevent *ev = NULL;
+
+		if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST)
+			reply = sctp_process_strreset_outreq(
+				(struct sctp_association *)asoc, param, &ev);
+		else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
+			reply = sctp_process_strreset_inreq(
+				(struct sctp_association *)asoc, param, &ev);
+		else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
+			reply = sctp_process_strreset_tsnreq(
+				(struct sctp_association *)asoc, param, &ev);
+		else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS)
+			reply = sctp_process_strreset_addstrm_out(
+				(struct sctp_association *)asoc, param, &ev);
+		else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS)
+			reply = sctp_process_strreset_addstrm_in(
+				(struct sctp_association *)asoc, param, &ev);
+		else if (param.p->type == SCTP_PARAM_RESET_RESPONSE)
+			reply = sctp_process_strreset_resp(
+				(struct sctp_association *)asoc, param, &ev);
+
+		if (ev)
+			sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+					SCTP_ULPEVENT(ev));
+
+		if (reply)
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+					SCTP_CHUNK(reply));
+	}
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
+ *
+ * When a FORWARD TSN chunk arrives, the data receiver MUST first update
+ * its cumulative TSN point to the value carried in the FORWARD TSN
+ * chunk, and then MUST further advance its cumulative TSN point locally
+ * if possible.
+ * After the above processing, the data receiver MUST stop reporting any
+ * missing TSNs earlier than or equal to the new cumulative TSN point.
+ *
+ * Verification Tag:  8.5 Verification Tag [Normal verification]
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
+					  const struct sctp_endpoint *ep,
+					  const struct sctp_association *asoc,
+					  const union sctp_subtype type,
+					  void *arg,
+					  struct sctp_cmd_seq *commands)
+{
+	struct sctp_fwdtsn_hdr *fwdtsn_hdr;
+	struct sctp_chunk *chunk = arg;
+	__u16 len;
+	__u32 tsn;
+
+	if (!sctp_vtag_verify(chunk, asoc)) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
+				SCTP_NULL());
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	if (!asoc->peer.prsctp_capable)
+		return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the FORWARD_TSN chunk has valid length.  */
+	if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
+	chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
+	len = ntohs(chunk->chunk_hdr->length);
+	len -= sizeof(struct sctp_chunkhdr);
+	skb_pull(chunk->skb, len);
+
+	tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
+	pr_debug("%s: TSN 0x%x\n", __func__, tsn);
+
+	/* The TSN is too high--silently discard the chunk and count on it
+	 * getting retransmitted later.
+	 */
+	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
+		goto discard_noforce;
+
+	if (!asoc->stream.si->validate_ftsn(chunk))
+		goto discard_noforce;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
+	if (len > sctp_ftsnhdr_len(&asoc->stream))
+		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
+				SCTP_CHUNK(chunk));
+
+	/* Count this as receiving DATA. */
+	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
+	}
+
+	/* FIXME: For now send a SACK, but DATA processing may
+	 * send another.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
+
+	return SCTP_DISPOSITION_CONSUME;
+
+discard_noforce:
+	return SCTP_DISPOSITION_DISCARD;
+}
+
+enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_fwdtsn_hdr *fwdtsn_hdr;
+	struct sctp_chunk *chunk = arg;
+	__u16 len;
+	__u32 tsn;
+
+	if (!sctp_vtag_verify(chunk, asoc)) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
+				SCTP_NULL());
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	if (!asoc->peer.prsctp_capable)
+		return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the FORWARD_TSN chunk has a valid length.  */
+	if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
+	chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
+	len = ntohs(chunk->chunk_hdr->length);
+	len -= sizeof(struct sctp_chunkhdr);
+	skb_pull(chunk->skb, len);
+
+	tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
+	pr_debug("%s: TSN 0x%x\n", __func__, tsn);
+
+	/* The TSN is too high--silently discard the chunk and count on it
+	 * getting retransmitted later.
+	 */
+	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
+		goto gen_shutdown;
+
+	if (!asoc->stream.si->validate_ftsn(chunk))
+		goto gen_shutdown;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
+	if (len > sctp_ftsnhdr_len(&asoc->stream))
+		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
+				SCTP_CHUNK(chunk));
+
+	/* Go a head and force a SACK, since we are shutting down. */
+gen_shutdown:
+	/* Implementor's Guide.
+	 *
+	 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
+	 * respond to each received packet containing one or more DATA chunk(s)
+	 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
+	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * SCTP-AUTH Section 6.3 Receiving authenticated chukns
+ *
+ *    The receiver MUST use the HMAC algorithm indicated in the HMAC
+ *    Identifier field.  If this algorithm was not specified by the
+ *    receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
+ *    during association setup, the AUTH chunk and all chunks after it MUST
+ *    be discarded and an ERROR chunk SHOULD be sent with the error cause
+ *    defined in Section 4.1.
+ *
+ *    If an endpoint with no shared key receives a Shared Key Identifier
+ *    other than 0, it MUST silently discard all authenticated chunks.  If
+ *    the endpoint has at least one endpoint pair shared key for the peer,
+ *    it MUST use the key specified by the Shared Key Identifier if a
+ *    key has been configured for that Shared Key Identifier.  If no
+ *    endpoint pair shared key has been configured for that Shared Key
+ *    Identifier, all authenticated chunks MUST be silently discarded.
+ *
+ * Verification Tag:  8.5 Verification Tag [Normal verification]
+ *
+ * The return value is the disposition of the chunk.
+ */
+static enum sctp_ierror sctp_sf_authenticate(
+					const struct sctp_association *asoc,
+					struct sctp_chunk *chunk)
+{
+	struct sctp_shared_key *sh_key = NULL;
+	struct sctp_authhdr *auth_hdr;
+	__u8 *save_digest, *digest;
+	struct sctp_hmac *hmac;
+	unsigned int sig_len;
+	__u16 key_id;
+
+	/* Pull in the auth header, so we can do some more verification */
+	auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
+	chunk->subh.auth_hdr = auth_hdr;
+	skb_pull(chunk->skb, sizeof(*auth_hdr));
+
+	/* Make sure that we support the HMAC algorithm from the auth
+	 * chunk.
+	 */
+	if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
+		return SCTP_IERROR_AUTH_BAD_HMAC;
+
+	/* Make sure that the provided shared key identifier has been
+	 * configured
+	 */
+	key_id = ntohs(auth_hdr->shkey_id);
+	if (key_id != asoc->active_key_id) {
+		sh_key = sctp_auth_get_shkey(asoc, key_id);
+		if (!sh_key)
+			return SCTP_IERROR_AUTH_BAD_KEYID;
+	}
+
+	/* Make sure that the length of the signature matches what
+	 * we expect.
+	 */
+	sig_len = ntohs(chunk->chunk_hdr->length) -
+		  sizeof(struct sctp_auth_chunk);
+	hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
+	if (sig_len != hmac->hmac_len)
+		return SCTP_IERROR_PROTO_VIOLATION;
+
+	/* Now that we've done validation checks, we can compute and
+	 * verify the hmac.  The steps involved are:
+	 *  1. Save the digest from the chunk.
+	 *  2. Zero out the digest in the chunk.
+	 *  3. Compute the new digest
+	 *  4. Compare saved and new digests.
+	 */
+	digest = auth_hdr->hmac;
+	skb_pull(chunk->skb, sig_len);
+
+	save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
+	if (!save_digest)
+		goto nomem;
+
+	memset(digest, 0, sig_len);
+
+	sctp_auth_calculate_hmac(asoc, chunk->skb,
+				 (struct sctp_auth_chunk *)chunk->chunk_hdr,
+				 sh_key, GFP_ATOMIC);
+
+	/* Discard the packet if the digests do not match */
+	if (memcmp(save_digest, digest, sig_len)) {
+		kfree(save_digest);
+		return SCTP_IERROR_BAD_SIG;
+	}
+
+	kfree(save_digest);
+	chunk->auth = 1;
+
+	return SCTP_IERROR_NO_ERROR;
+nomem:
+	return SCTP_IERROR_NOMEM;
+}
+
+enum sctp_disposition sctp_sf_eat_auth(struct net *net,
+				       const struct sctp_endpoint *ep,
+				       const struct sctp_association *asoc,
+				       const union sctp_subtype type,
+				       void *arg, struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_authhdr *auth_hdr;
+	struct sctp_chunk *err_chunk;
+	enum sctp_ierror error;
+
+	/* Make sure that the peer has AUTH capable */
+	if (!asoc->peer.auth_capable)
+		return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
+
+	if (!sctp_vtag_verify(chunk, asoc)) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
+				SCTP_NULL());
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
+	/* Make sure that the AUTH chunk has valid length.  */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
+	error = sctp_sf_authenticate(asoc, chunk);
+	switch (error) {
+	case SCTP_IERROR_AUTH_BAD_HMAC:
+		/* Generate the ERROR chunk and discard the rest
+		 * of the packet
+		 */
+		err_chunk = sctp_make_op_error(asoc, chunk,
+					       SCTP_ERROR_UNSUP_HMAC,
+					       &auth_hdr->hmac_id,
+					       sizeof(__u16), 0);
+		if (err_chunk) {
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+					SCTP_CHUNK(err_chunk));
+		}
+		fallthrough;
+	case SCTP_IERROR_AUTH_BAD_KEYID:
+	case SCTP_IERROR_BAD_SIG:
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	case SCTP_IERROR_PROTO_VIOLATION:
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	case SCTP_IERROR_NOMEM:
+		return SCTP_DISPOSITION_NOMEM;
+
+	default:			/* Prevent gcc warnings */
+		break;
+	}
+
+	if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
+		struct sctp_ulpevent *ev;
+
+		ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
+				    SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
+
+		if (!ev)
+			return SCTP_DISPOSITION_NOMEM;
+
+		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
+				SCTP_ULPEVENT(ev));
+	}
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Process an unknown chunk.
+ *
+ * Section: 3.2. Also, 2.1 in the implementor's guide.
+ *
+ * Chunk Types are encoded such that the highest-order two bits specify
+ * the action that must be taken if the processing endpoint does not
+ * recognize the Chunk Type.
+ *
+ * 00 - Stop processing this SCTP packet and discard it, do not process
+ *      any further chunks within it.
+ *
+ * 01 - Stop processing this SCTP packet and discard it, do not process
+ *      any further chunks within it, and report the unrecognized
+ *      chunk in an 'Unrecognized Chunk Type'.
+ *
+ * 10 - Skip this chunk and continue processing.
+ *
+ * 11 - Skip this chunk and continue processing, but report in an ERROR
+ *      Chunk using the 'Unrecognized Chunk Type' cause of error.
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_unk_chunk(struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *unk_chunk = arg;
+	struct sctp_chunk *err_chunk;
+	struct sctp_chunkhdr *hdr;
+
+	pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
+
+	if (!sctp_vtag_verify(unk_chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the chunk has a valid length.
+	 * Since we don't know the chunk type, we use a general
+	 * chunkhdr structure to make a comparison.
+	 */
+	if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	switch (type.chunk & SCTP_CID_ACTION_MASK) {
+	case SCTP_CID_ACTION_DISCARD:
+		/* Discard the packet.  */
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	case SCTP_CID_ACTION_DISCARD_ERR:
+		/* Generate an ERROR chunk as response. */
+		hdr = unk_chunk->chunk_hdr;
+		err_chunk = sctp_make_op_error(asoc, unk_chunk,
+					       SCTP_ERROR_UNKNOWN_CHUNK, hdr,
+					       SCTP_PAD4(ntohs(hdr->length)),
+					       0);
+		if (err_chunk) {
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+					SCTP_CHUNK(err_chunk));
+		}
+
+		/* Discard the packet.  */
+		sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+		return SCTP_DISPOSITION_CONSUME;
+	case SCTP_CID_ACTION_SKIP:
+		/* Skip the chunk.  */
+		return SCTP_DISPOSITION_DISCARD;
+	case SCTP_CID_ACTION_SKIP_ERR:
+		/* Generate an ERROR chunk as response. */
+		hdr = unk_chunk->chunk_hdr;
+		err_chunk = sctp_make_op_error(asoc, unk_chunk,
+					       SCTP_ERROR_UNKNOWN_CHUNK, hdr,
+					       SCTP_PAD4(ntohs(hdr->length)),
+					       0);
+		if (err_chunk) {
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+					SCTP_CHUNK(err_chunk));
+		}
+		/* Skip the chunk.  */
+		return SCTP_DISPOSITION_CONSUME;
+	default:
+		break;
+	}
+
+	return SCTP_DISPOSITION_DISCARD;
+}
+
+/*
+ * Discard the chunk.
+ *
+ * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
+ * [Too numerous to mention...]
+ * Verification Tag: No verification needed.
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_discard_chunk(struct net *net,
+					    const struct sctp_endpoint *ep,
+					    const struct sctp_association *asoc,
+					    const union sctp_subtype type,
+					    void *arg,
+					    struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+
+	if (asoc && !sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the chunk has a valid length.
+	 * Since we don't know the chunk type, we use a general
+	 * chunkhdr structure to make a comparison.
+	 */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
+
+	return SCTP_DISPOSITION_DISCARD;
+}
+
+/*
+ * Discard the whole packet.
+ *
+ * Section: 8.4 2)
+ *
+ * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
+ *    silently discard the OOTB packet and take no further action.
+ *
+ * Verification Tag: No verification necessary
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_pdiscard(struct net *net,
+				       const struct sctp_endpoint *ep,
+				       const struct sctp_association *asoc,
+				       const union sctp_subtype type,
+				       void *arg, struct sctp_cmd_seq *commands)
+{
+	SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
+	sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+
+/*
+ * The other end is violating protocol.
+ *
+ * Section: Not specified
+ * Verification Tag: Not specified
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (asoc, reply_msg, msg_up, timers, counters)
+ *
+ * We simply tag the chunk as a violation.  The state machine will log
+ * the violation and continue.
+ */
+enum sctp_disposition sctp_sf_violation(struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
+	/* Make sure that the chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
+		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
+						  commands);
+
+	return SCTP_DISPOSITION_VIOLATION;
+}
+
+/*
+ * Common function to handle a protocol violation.
+ */
+static enum sctp_disposition sctp_sf_abort_violation(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					void *arg,
+					struct sctp_cmd_seq *commands,
+					const __u8 *payload,
+					const size_t paylen)
+{
+	struct sctp_packet *packet = NULL;
+	struct sctp_chunk *chunk =  arg;
+	struct sctp_chunk *abort = NULL;
+
+	/* SCTP-AUTH, Section 6.3:
+	 *    It should be noted that if the receiver wants to tear
+	 *    down an association in an authenticated way only, the
+	 *    handling of malformed packets should not result in
+	 *    tearing down the association.
+	 *
+	 * This means that if we only want to abort associations
+	 * in an authenticated way (i.e AUTH+ABORT), then we
+	 * can't destroy this association just because the packet
+	 * was malformed.
+	 */
+	if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
+		goto discard;
+
+	/* Make the abort chunk. */
+	abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
+	if (!abort)
+		goto nomem;
+
+	if (asoc) {
+		/* Treat INIT-ACK as a special case during COOKIE-WAIT. */
+		if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
+		    !asoc->peer.i.init_tag) {
+			struct sctp_initack_chunk *initack;
+
+			initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
+			if (!sctp_chunk_length_valid(chunk, sizeof(*initack)))
+				abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
+			else {
+				unsigned int inittag;
+
+				inittag = ntohl(initack->init_hdr.init_tag);
+				sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
+						SCTP_U32(inittag));
+			}
+		}
+
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
+		SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+
+		if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
+			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
+			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+					SCTP_ERROR(ECONNREFUSED));
+			sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
+					SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
+		} else {
+			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+					SCTP_ERROR(ECONNABORTED));
+			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+					SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
+			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		}
+	} else {
+		packet = sctp_ootb_pkt_new(net, asoc, chunk);
+
+		if (!packet)
+			goto nomem_pkt;
+
+		if (sctp_test_T_bit(abort))
+			packet->vtag = ntohl(chunk->sctp_hdr->vtag);
+
+		abort->skb->sk = ep->base.sk;
+
+		sctp_packet_append_chunk(packet, abort);
+
+		sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
+			SCTP_PACKET(packet));
+
+		SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+	}
+
+	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+
+discard:
+	sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
+	return SCTP_DISPOSITION_ABORT;
+
+nomem_pkt:
+	sctp_chunk_free(abort);
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Handle a protocol violation when the chunk length is invalid.
+ * "Invalid" length is identified as smaller than the minimal length a
+ * given chunk can be.  For example, a SACK chunk has invalid length
+ * if its length is set to be smaller than the size of struct sctp_sack_chunk.
+ *
+ * We inform the other end by sending an ABORT with a Protocol Violation
+ * error code.
+ *
+ * Section: Not specified
+ * Verification Tag:  Nothing to do
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * Outputs
+ * (reply_msg, msg_up, counters)
+ *
+ * Generate an  ABORT chunk and terminate the association.
+ */
+static enum sctp_disposition sctp_sf_violation_chunklen(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	static const char err_str[] = "The following chunk had invalid length:";
+
+	return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
+				       sizeof(err_str));
+}
+
+/*
+ * Handle a protocol violation when the parameter length is invalid.
+ * If the length is smaller than the minimum length of a given parameter,
+ * or accumulated length in multi parameters exceeds the end of the chunk,
+ * the length is considered as invalid.
+ */
+static enum sctp_disposition sctp_sf_violation_paramlen(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg, void *ext,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_paramhdr *param = ext;
+	struct sctp_chunk *abort = NULL;
+	struct sctp_chunk *chunk = arg;
+
+	if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
+		goto discard;
+
+	/* Make the abort chunk. */
+	abort = sctp_make_violation_paramlen(asoc, chunk, param);
+	if (!abort)
+		goto nomem;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
+	SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+			SCTP_ERROR(ECONNABORTED));
+	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+			SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
+	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+
+discard:
+	sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
+	return SCTP_DISPOSITION_ABORT;
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/* Handle a protocol violation when the peer trying to advance the
+ * cumulative tsn ack to a point beyond the max tsn currently sent.
+ *
+ * We inform the other end by sending an ABORT with a Protocol Violation
+ * error code.
+ */
+static enum sctp_disposition sctp_sf_violation_ctsn(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
+
+	return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
+				       sizeof(err_str));
+}
+
+/* Handle protocol violation of an invalid chunk bundling.  For example,
+ * when we have an association and we receive bundled INIT-ACK, or
+ * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
+ * statement from the specs.  Additionally, there might be an attacker
+ * on the path and we may not want to continue this communication.
+ */
+static enum sctp_disposition sctp_sf_violation_chunk(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	static const char err_str[] = "The following chunk violates protocol:";
+
+	if (!asoc)
+		return sctp_sf_violation(net, ep, asoc, type, arg, commands);
+
+	return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
+				       sizeof(err_str));
+}
+/***************************************************************************
+ * These are the state functions for handling primitive (Section 10) events.
+ ***************************************************************************/
+/*
+ * sctp_sf_do_prm_asoc
+ *
+ * Section: 10.1 ULP-to-SCTP
+ * B) Associate
+ *
+ * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
+ * outbound stream count)
+ * -> association id [,destination transport addr list] [,outbound stream
+ * count]
+ *
+ * This primitive allows the upper layer to initiate an association to a
+ * specific peer endpoint.
+ *
+ * The peer endpoint shall be specified by one of the transport addresses
+ * which defines the endpoint (see Section 1.4).  If the local SCTP
+ * instance has not been initialized, the ASSOCIATE is considered an
+ * error.
+ * [This is not relevant for the kernel implementation since we do all
+ * initialization at boot time.  It we hadn't initialized we wouldn't
+ * get anywhere near this code.]
+ *
+ * An association id, which is a local handle to the SCTP association,
+ * will be returned on successful establishment of the association. If
+ * SCTP is not able to open an SCTP association with the peer endpoint,
+ * an error is returned.
+ * [In the kernel implementation, the struct sctp_association needs to
+ * be created BEFORE causing this primitive to run.]
+ *
+ * Other association parameters may be returned, including the
+ * complete destination transport addresses of the peer as well as the
+ * outbound stream count of the local endpoint. One of the transport
+ * address from the returned destination addresses will be selected by
+ * the local endpoint as default primary path for sending SCTP packets
+ * to this peer.  The returned "destination transport addr list" can
+ * be used by the ULP to change the default primary path or to force
+ * sending a packet to a specific transport address.  [All of this
+ * stuff happens when the INIT ACK arrives.  This is a NON-BLOCKING
+ * function.]
+ *
+ * Mandatory attributes:
+ *
+ * o local SCTP instance name - obtained from the INITIALIZE operation.
+ *   [This is the argument asoc.]
+ * o destination transport addr - specified as one of the transport
+ * addresses of the peer endpoint with which the association is to be
+ * established.
+ *  [This is asoc->peer.active_path.]
+ * o outbound stream count - the number of outbound streams the ULP
+ * would like to open towards this peer endpoint.
+ * [BUG: This is not currently implemented.]
+ * Optional attributes:
+ *
+ * None.
+ *
+ * The return value is a disposition.
+ */
+enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
+					  const struct sctp_endpoint *ep,
+					  const struct sctp_association *asoc,
+					  const union sctp_subtype type,
+					  void *arg,
+					  struct sctp_cmd_seq *commands)
+{
+	struct sctp_association *my_asoc;
+	struct sctp_chunk *repl;
+
+	/* The comment below says that we enter COOKIE-WAIT AFTER
+	 * sending the INIT, but that doesn't actually work in our
+	 * implementation...
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
+
+	/* RFC 2960 5.1 Normal Establishment of an Association
+	 *
+	 * A) "A" first sends an INIT chunk to "Z".  In the INIT, "A"
+	 * must provide its Verification Tag (Tag_A) in the Initiate
+	 * Tag field.  Tag_A SHOULD be a random number in the range of
+	 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
+	 */
+
+	repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
+	if (!repl)
+		goto nomem;
+
+	/* Choose transport for INIT. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
+			SCTP_CHUNK(repl));
+
+	/* Cast away the const modifier, as we want to just
+	 * rerun it through as a sideffect.
+	 */
+	my_asoc = (struct sctp_association *)asoc;
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
+
+	/* After sending the INIT, "A" starts the T1-init timer and
+	 * enters the COOKIE-WAIT state.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Process the SEND primitive.
+ *
+ * Section: 10.1 ULP-to-SCTP
+ * E) Send
+ *
+ * Format: SEND(association id, buffer address, byte count [,context]
+ *         [,stream id] [,life time] [,destination transport address]
+ *         [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
+ * -> result
+ *
+ * This is the main method to send user data via SCTP.
+ *
+ * Mandatory attributes:
+ *
+ *  o association id - local handle to the SCTP association
+ *
+ *  o buffer address - the location where the user message to be
+ *    transmitted is stored;
+ *
+ *  o byte count - The size of the user data in number of bytes;
+ *
+ * Optional attributes:
+ *
+ *  o context - an optional 32 bit integer that will be carried in the
+ *    sending failure notification to the ULP if the transportation of
+ *    this User Message fails.
+ *
+ *  o stream id - to indicate which stream to send the data on. If not
+ *    specified, stream 0 will be used.
+ *
+ *  o life time - specifies the life time of the user data. The user data
+ *    will not be sent by SCTP after the life time expires. This
+ *    parameter can be used to avoid efforts to transmit stale
+ *    user messages. SCTP notifies the ULP if the data cannot be
+ *    initiated to transport (i.e. sent to the destination via SCTP's
+ *    send primitive) within the life time variable. However, the
+ *    user data will be transmitted if SCTP has attempted to transmit a
+ *    chunk before the life time expired.
+ *
+ *  o destination transport address - specified as one of the destination
+ *    transport addresses of the peer endpoint to which this packet
+ *    should be sent. Whenever possible, SCTP should use this destination
+ *    transport address for sending the packets, instead of the current
+ *    primary path.
+ *
+ *  o unorder flag - this flag, if present, indicates that the user
+ *    would like the data delivered in an unordered fashion to the peer
+ *    (i.e., the U flag is set to 1 on all DATA chunks carrying this
+ *    message).
+ *
+ *  o no-bundle flag - instructs SCTP not to bundle this user data with
+ *    other outbound DATA chunks. SCTP MAY still bundle even when
+ *    this flag is present, when faced with network congestion.
+ *
+ *  o payload protocol-id - A 32 bit unsigned integer that is to be
+ *    passed to the peer indicating the type of payload protocol data
+ *    being transmitted. This value is passed as opaque data by SCTP.
+ *
+ * The return value is the disposition.
+ */
+enum sctp_disposition sctp_sf_do_prm_send(struct net *net,
+					  const struct sctp_endpoint *ep,
+					  const struct sctp_association *asoc,
+					  const union sctp_subtype type,
+					  void *arg,
+					  struct sctp_cmd_seq *commands)
+{
+	struct sctp_datamsg *msg = arg;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Process the SHUTDOWN primitive.
+ *
+ * Section: 10.1:
+ * C) Shutdown
+ *
+ * Format: SHUTDOWN(association id)
+ * -> result
+ *
+ * Gracefully closes an association. Any locally queued user data
+ * will be delivered to the peer. The association will be terminated only
+ * after the peer acknowledges all the SCTP packets sent.  A success code
+ * will be returned on successful termination of the association. If
+ * attempting to terminate the association results in a failure, an error
+ * code shall be returned.
+ *
+ * Mandatory attributes:
+ *
+ *  o association id - local handle to the SCTP association
+ *
+ * Optional attributes:
+ *
+ * None.
+ *
+ * The return value is the disposition.
+ */
+enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	enum sctp_disposition disposition;
+
+	/* From 9.2 Shutdown of an Association
+	 * Upon receipt of the SHUTDOWN primitive from its upper
+	 * layer, the endpoint enters SHUTDOWN-PENDING state and
+	 * remains there until all outstanding data has been
+	 * acknowledged by its peer. The endpoint accepts no new data
+	 * from its upper layer, but retransmits data to the far end
+	 * if necessary to fill gaps.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
+
+	disposition = SCTP_DISPOSITION_CONSUME;
+	if (sctp_outq_is_empty(&asoc->outqueue)) {
+		disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
+							    arg, commands);
+	}
+
+	return disposition;
+}
+
+/*
+ * Process the ABORT primitive.
+ *
+ * Section: 10.1:
+ * C) Abort
+ *
+ * Format: Abort(association id [, cause code])
+ * -> result
+ *
+ * Ungracefully closes an association. Any locally queued user data
+ * will be discarded and an ABORT chunk is sent to the peer.  A success code
+ * will be returned on successful abortion of the association. If
+ * attempting to abort the association results in a failure, an error
+ * code shall be returned.
+ *
+ * Mandatory attributes:
+ *
+ *  o association id - local handle to the SCTP association
+ *
+ * Optional attributes:
+ *
+ *  o cause code - reason of the abort to be passed to the peer
+ *
+ * None.
+ *
+ * The return value is the disposition.
+ */
+enum sctp_disposition sctp_sf_do_9_1_prm_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* From 9.1 Abort of an Association
+	 * Upon receipt of the ABORT primitive from its upper
+	 * layer, the endpoint enters CLOSED state and
+	 * discard all outstanding data has been
+	 * acknowledged by its peer. The endpoint accepts no new data
+	 * from its upper layer, but retransmits data to the far end
+	 * if necessary to fill gaps.
+	 */
+	struct sctp_chunk *abort = arg;
+
+	if (abort)
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
+
+	/* Even if we can't send the ABORT due to low memory delete the
+	 * TCB.  This is a departure from our typical NOMEM handling.
+	 */
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+			SCTP_ERROR(ECONNABORTED));
+	/* Delete the established association. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+			SCTP_PERR(SCTP_ERROR_USER_ABORT));
+
+	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+
+	return SCTP_DISPOSITION_ABORT;
+}
+
+/* We tried an illegal operation on an association which is closed.  */
+enum sctp_disposition sctp_sf_error_closed(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/* We tried an illegal operation on an association which is shutting
+ * down.
+ */
+enum sctp_disposition sctp_sf_error_shutdown(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
+			SCTP_ERROR(-ESHUTDOWN));
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * sctp_cookie_wait_prm_shutdown
+ *
+ * Section: 4 Note: 2
+ * Verification Tag:
+ * Inputs
+ * (endpoint, asoc)
+ *
+ * The RFC does not explicitly address this issue, but is the route through the
+ * state table when someone issues a shutdown while in COOKIE_WAIT state.
+ *
+ * Outputs
+ * (timers)
+ */
+enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_CLOSED));
+
+	SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
+
+	return SCTP_DISPOSITION_DELETE_TCB;
+}
+
+/*
+ * sctp_cookie_echoed_prm_shutdown
+ *
+ * Section: 4 Note: 2
+ * Verification Tag:
+ * Inputs
+ * (endpoint, asoc)
+ *
+ * The RFC does not explcitly address this issue, but is the route through the
+ * state table when someone issues a shutdown while in COOKIE_ECHOED state.
+ *
+ * Outputs
+ * (timers)
+ */
+enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* There is a single T1 timer, so we should be able to use
+	 * common function with the COOKIE-WAIT state.
+	 */
+	return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * sctp_sf_cookie_wait_prm_abort
+ *
+ * Section: 4 Note: 2
+ * Verification Tag:
+ * Inputs
+ * (endpoint, asoc)
+ *
+ * The RFC does not explicitly address this issue, but is the route through the
+ * state table when someone issues an abort while in COOKIE_WAIT state.
+ *
+ * Outputs
+ * (timers)
+ */
+enum sctp_disposition sctp_sf_cookie_wait_prm_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *abort = arg;
+
+	/* Stop T1-init timer */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
+
+	if (abort)
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_CLOSED));
+
+	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+
+	/* Even if we can't send the ABORT due to low memory delete the
+	 * TCB.  This is a departure from our typical NOMEM handling.
+	 */
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+			SCTP_ERROR(ECONNREFUSED));
+	/* Delete the established association. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
+			SCTP_PERR(SCTP_ERROR_USER_ABORT));
+
+	return SCTP_DISPOSITION_ABORT;
+}
+
+/*
+ * sctp_sf_cookie_echoed_prm_abort
+ *
+ * Section: 4 Note: 3
+ * Verification Tag:
+ * Inputs
+ * (endpoint, asoc)
+ *
+ * The RFC does not explcitly address this issue, but is the route through the
+ * state table when someone issues an abort while in COOKIE_ECHOED state.
+ *
+ * Outputs
+ * (timers)
+ */
+enum sctp_disposition sctp_sf_cookie_echoed_prm_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* There is a single T1 timer, so we should be able to use
+	 * common function with the COOKIE-WAIT state.
+	 */
+	return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * sctp_sf_shutdown_pending_prm_abort
+ *
+ * Inputs
+ * (endpoint, asoc)
+ *
+ * The RFC does not explicitly address this issue, but is the route through the
+ * state table when someone issues an abort while in SHUTDOWN-PENDING state.
+ *
+ * Outputs
+ * (timers)
+ */
+enum sctp_disposition sctp_sf_shutdown_pending_prm_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* Stop the T5-shutdown guard timer.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
+
+	return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * sctp_sf_shutdown_sent_prm_abort
+ *
+ * Inputs
+ * (endpoint, asoc)
+ *
+ * The RFC does not explicitly address this issue, but is the route through the
+ * state table when someone issues an abort while in SHUTDOWN-SENT state.
+ *
+ * Outputs
+ * (timers)
+ */
+enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* Stop the T2-shutdown timer.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+
+	/* Stop the T5-shutdown guard timer.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
+
+	return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * sctp_sf_cookie_echoed_prm_abort
+ *
+ * Inputs
+ * (endpoint, asoc)
+ *
+ * The RFC does not explcitly address this issue, but is the route through the
+ * state table when someone issues an abort while in COOKIE_ECHOED state.
+ *
+ * Outputs
+ * (timers)
+ */
+enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	/* The same T2 timer, so we should be able to use
+	 * common function with the SHUTDOWN-SENT state.
+	 */
+	return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
+}
+
+/*
+ * Process the REQUESTHEARTBEAT primitive
+ *
+ * 10.1 ULP-to-SCTP
+ * J) Request Heartbeat
+ *
+ * Format: REQUESTHEARTBEAT(association id, destination transport address)
+ *
+ * -> result
+ *
+ * Instructs the local endpoint to perform a HeartBeat on the specified
+ * destination transport address of the given association. The returned
+ * result should indicate whether the transmission of the HEARTBEAT
+ * chunk to the destination address is successful.
+ *
+ * Mandatory attributes:
+ *
+ * o association id - local handle to the SCTP association
+ *
+ * o destination transport address - the transport address of the
+ *   association on which a heartbeat should be issued.
+ */
+enum sctp_disposition sctp_sf_do_prm_requestheartbeat(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
+				      (struct sctp_transport *)arg, commands))
+		return SCTP_DISPOSITION_NOMEM;
+
+	/*
+	 * RFC 2960 (bis), section 8.3
+	 *
+	 *    D) Request an on-demand HEARTBEAT on a specific destination
+	 *    transport address of a given association.
+	 *
+	 *    The endpoint should increment the respective error  counter of
+	 *    the destination transport address each time a HEARTBEAT is sent
+	 *    to that address and not acknowledged within one RTO.
+	 *
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
+			SCTP_TRANSPORT(arg));
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * ADDIP Section 4.1 ASCONF Chunk Procedures
+ * When an endpoint has an ASCONF signaled change to be sent to the
+ * remote endpoint it should do A1 to A9
+ */
+enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
+					    const struct sctp_endpoint *ep,
+					    const struct sctp_association *asoc,
+					    const union sctp_subtype type,
+					    void *arg,
+					    struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/* RE-CONFIG Section 5.1 RECONF Chunk Procedures */
+enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net,
+					    const struct sctp_endpoint *ep,
+					    const struct sctp_association *asoc,
+					    const union sctp_subtype type,
+					    void *arg,
+					    struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Ignore the primitive event
+ *
+ * The return value is the disposition of the primitive.
+ */
+enum sctp_disposition sctp_sf_ignore_primitive(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	pr_debug("%s: primitive type:%d is ignored\n", __func__,
+		 type.primitive);
+
+	return SCTP_DISPOSITION_DISCARD;
+}
+
+/***************************************************************************
+ * These are the state functions for the OTHER events.
+ ***************************************************************************/
+
+/*
+ * When the SCTP stack has no more user data to send or retransmit, this
+ * notification is given to the user. Also, at the time when a user app
+ * subscribes to this event, if there is no data to be sent or
+ * retransmit, the stack will immediately send up this notification.
+ */
+enum sctp_disposition sctp_sf_do_no_pending_tsn(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_ulpevent *event;
+
+	event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
+	if (!event)
+		return SCTP_DISPOSITION_NOMEM;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Start the shutdown negotiation.
+ *
+ * From Section 9.2:
+ * Once all its outstanding data has been acknowledged, the endpoint
+ * shall send a SHUTDOWN chunk to its peer including in the Cumulative
+ * TSN Ack field the last sequential TSN it has received from the peer.
+ * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
+ * state. If the timer expires, the endpoint must re-send the SHUTDOWN
+ * with the updated last sequential TSN received from its peer.
+ *
+ * The return value is the disposition.
+ */
+enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *reply;
+
+	/* Once all its outstanding data has been acknowledged, the
+	 * endpoint shall send a SHUTDOWN chunk to its peer including
+	 * in the Cumulative TSN Ack field the last sequential TSN it
+	 * has received from the peer.
+	 */
+	reply = sctp_make_shutdown(asoc, arg);
+	if (!reply)
+		goto nomem;
+
+	/* Set the transport for the SHUTDOWN chunk and the timeout for the
+	 * T2-shutdown timer.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
+
+	/* It shall then start the T2-shutdown timer */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+
+	/* RFC 4960 Section 9.2
+	 * The sender of the SHUTDOWN MAY also start an overall guard timer
+	 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
+
+	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
+
+	/* and enter the SHUTDOWN-SENT state.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
+
+	/* sctp-implguide 2.10 Issues with Heartbeating and failover
+	 *
+	 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
+	 * or SHUTDOWN-ACK.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Generate a SHUTDOWN ACK now that everything is SACK'd.
+ *
+ * From Section 9.2:
+ *
+ * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
+ * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
+ * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
+ * endpoint must re-send the SHUTDOWN ACK.
+ *
+ * The return value is the disposition.
+ */
+enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sctp_chunk *reply;
+
+	/* There are 2 ways of getting here:
+	 *    1) called in response to a SHUTDOWN chunk
+	 *    2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
+	 *
+	 * For the case (2), the arg parameter is set to NULL.  We need
+	 * to check that we have a chunk before accessing it's fields.
+	 */
+	if (chunk) {
+		if (!sctp_vtag_verify(chunk, asoc))
+			return sctp_sf_pdiscard(net, ep, asoc, type, arg,
+						commands);
+
+		/* Make sure that the SHUTDOWN chunk has a valid length. */
+		if (!sctp_chunk_length_valid(
+				chunk, sizeof(struct sctp_shutdown_chunk)))
+			return sctp_sf_violation_chunklen(net, ep, asoc, type,
+							  arg, commands);
+	}
+
+	/* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
+	 * shall send a SHUTDOWN ACK ...
+	 */
+	reply = sctp_make_shutdown_ack(asoc, chunk);
+	if (!reply)
+		goto nomem;
+
+	/* Set the transport for the SHUTDOWN ACK chunk and the timeout for
+	 * the T2-shutdown timer.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
+
+	/* and start/restart a T2-shutdown timer of its own, */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+
+	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
+
+	/* Enter the SHUTDOWN-ACK-SENT state.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
+
+	/* sctp-implguide 2.10 Issues with Heartbeating and failover
+	 *
+	 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
+	 * or SHUTDOWN-ACK.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * Ignore the event defined as other
+ *
+ * The return value is the disposition of the event.
+ */
+enum sctp_disposition sctp_sf_ignore_other(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	pr_debug("%s: the event other type:%d is ignored\n",
+		 __func__, type.other);
+
+	return SCTP_DISPOSITION_DISCARD;
+}
+
+/************************************************************
+ * These are the state functions for handling timeout events.
+ ************************************************************/
+
+/*
+ * RTX Timeout
+ *
+ * Section: 6.3.3 Handle T3-rtx Expiration
+ *
+ * Whenever the retransmission timer T3-rtx expires for a destination
+ * address, do the following:
+ * [See below]
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	struct sctp_transport *transport = arg;
+
+	SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
+
+	if (asoc->overall_error_count >= asoc->max_retrans) {
+		if (asoc->peer.zero_window_announced &&
+		    asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
+			/*
+			 * We are here likely because the receiver had its rwnd
+			 * closed for a while and we have not been able to
+			 * transmit the locally queued data within the maximum
+			 * retransmission attempts limit.  Start the T5
+			 * shutdown guard timer to give the receiver one last
+			 * chance and some additional time to recover before
+			 * aborting.
+			 */
+			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
+		} else {
+			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+					SCTP_ERROR(ETIMEDOUT));
+			/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
+			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+					SCTP_PERR(SCTP_ERROR_NO_ERROR));
+			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+			return SCTP_DISPOSITION_DELETE_TCB;
+		}
+	}
+
+	/* E1) For the destination address for which the timer
+	 * expires, adjust its ssthresh with rules defined in Section
+	 * 7.2.3 and set the cwnd <- MTU.
+	 */
+
+	/* E2) For the destination address for which the timer
+	 * expires, set RTO <- RTO * 2 ("back off the timer").  The
+	 * maximum value discussed in rule C7 above (RTO.max) may be
+	 * used to provide an upper bound to this doubling operation.
+	 */
+
+	/* E3) Determine how many of the earliest (i.e., lowest TSN)
+	 * outstanding DATA chunks for the address for which the
+	 * T3-rtx has expired will fit into a single packet, subject
+	 * to the MTU constraint for the path corresponding to the
+	 * destination transport address to which the retransmission
+	 * is being sent (this may be different from the address for
+	 * which the timer expires [see Section 6.4]).  Call this
+	 * value K. Bundle and retransmit those K DATA chunks in a
+	 * single packet to the destination endpoint.
+	 *
+	 * Note: Any DATA chunks that were sent to the address for
+	 * which the T3-rtx timer expired but did not fit in one MTU
+	 * (rule E3 above), should be marked for retransmission and
+	 * sent as soon as cwnd allows (normally when a SACK arrives).
+	 */
+
+	/* Do some failure management (Section 8.2). */
+	sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
+
+	/* NB: Rules E4 and F1 are implicit in R1.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * Generate delayed SACK on timeout
+ *
+ * Section: 6.2  Acknowledgement on Reception of DATA Chunks
+ *
+ * The guidelines on delayed acknowledgement algorithm specified in
+ * Section 4.2 of [RFC2581] SHOULD be followed.  Specifically, an
+ * acknowledgement SHOULD be generated for at least every second packet
+ * (not every second DATA chunk) received, and SHOULD be generated
+ * within 200 ms of the arrival of any unacknowledged DATA chunk.  In
+ * some situations it may be beneficial for an SCTP transmitter to be
+ * more conservative than the algorithms detailed in this document
+ * allow. However, an SCTP transmitter MUST NOT be more aggressive than
+ * the following algorithms allow.
+ */
+enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net,
+					  const struct sctp_endpoint *ep,
+					  const struct sctp_association *asoc,
+					  const union sctp_subtype type,
+					  void *arg,
+					  struct sctp_cmd_seq *commands)
+{
+	SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
+	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * sctp_sf_t1_init_timer_expire
+ *
+ * Section: 4 Note: 2
+ * Verification Tag:
+ * Inputs
+ * (endpoint, asoc)
+ *
+ *  RFC 2960 Section 4 Notes
+ *  2) If the T1-init timer expires, the endpoint MUST retransmit INIT
+ *     and re-start the T1-init timer without changing state.  This MUST
+ *     be repeated up to 'Max.Init.Retransmits' times.  After that, the
+ *     endpoint MUST abort the initialization process and report the
+ *     error to SCTP user.
+ *
+ * Outputs
+ * (timers, events)
+ *
+ */
+enum sctp_disposition sctp_sf_t1_init_timer_expire(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	int attempts = asoc->init_err_counter + 1;
+	struct sctp_chunk *repl = NULL;
+	struct sctp_bind_addr *bp;
+
+	pr_debug("%s: timer T1 expired (INIT)\n", __func__);
+
+	SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
+
+	if (attempts <= asoc->max_init_attempts) {
+		bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
+		repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
+		if (!repl)
+			return SCTP_DISPOSITION_NOMEM;
+
+		/* Choose transport for INIT. */
+		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
+				SCTP_CHUNK(repl));
+
+		/* Issue a sideeffect to do the needed accounting. */
+		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
+
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+	} else {
+		pr_debug("%s: giving up on INIT, attempts:%d "
+			 "max_init_attempts:%d\n", __func__, attempts,
+			 asoc->max_init_attempts);
+
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ETIMEDOUT));
+		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
+				SCTP_PERR(SCTP_ERROR_NO_ERROR));
+		return SCTP_DISPOSITION_DELETE_TCB;
+	}
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/*
+ * sctp_sf_t1_cookie_timer_expire
+ *
+ * Section: 4 Note: 2
+ * Verification Tag:
+ * Inputs
+ * (endpoint, asoc)
+ *
+ *  RFC 2960 Section 4 Notes
+ *  3) If the T1-cookie timer expires, the endpoint MUST retransmit
+ *     COOKIE ECHO and re-start the T1-cookie timer without changing
+ *     state.  This MUST be repeated up to 'Max.Init.Retransmits' times.
+ *     After that, the endpoint MUST abort the initialization process and
+ *     report the error to SCTP user.
+ *
+ * Outputs
+ * (timers, events)
+ *
+ */
+enum sctp_disposition sctp_sf_t1_cookie_timer_expire(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	int attempts = asoc->init_err_counter + 1;
+	struct sctp_chunk *repl = NULL;
+
+	pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
+
+	SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
+
+	if (attempts <= asoc->max_init_attempts) {
+		repl = sctp_make_cookie_echo(asoc, NULL);
+		if (!repl)
+			return SCTP_DISPOSITION_NOMEM;
+
+		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
+				SCTP_CHUNK(repl));
+		/* Issue a sideeffect to do the needed accounting. */
+		sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
+
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+	} else {
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ETIMEDOUT));
+		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
+				SCTP_PERR(SCTP_ERROR_NO_ERROR));
+		return SCTP_DISPOSITION_DELETE_TCB;
+	}
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
+ * with the updated last sequential TSN received from its peer.
+ *
+ * An endpoint should limit the number of retransmissions of the
+ * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
+ * If this threshold is exceeded the endpoint should destroy the TCB and
+ * MUST report the peer endpoint unreachable to the upper layer (and
+ * thus the association enters the CLOSED state).  The reception of any
+ * packet from its peer (i.e. as the peer sends all of its queued DATA
+ * chunks) should clear the endpoint's retransmission count and restart
+ * the T2-Shutdown timer,  giving its peer ample opportunity to transmit
+ * all of its queued DATA chunks that have not yet been sent.
+ */
+enum sctp_disposition sctp_sf_t2_timer_expire(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *reply = NULL;
+
+	pr_debug("%s: timer T2 expired\n", __func__);
+
+	SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
+
+	((struct sctp_association *)asoc)->shutdown_retries++;
+
+	if (asoc->overall_error_count >= asoc->max_retrans) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ETIMEDOUT));
+		/* Note:  CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
+		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+				SCTP_PERR(SCTP_ERROR_NO_ERROR));
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		return SCTP_DISPOSITION_DELETE_TCB;
+	}
+
+	switch (asoc->state) {
+	case SCTP_STATE_SHUTDOWN_SENT:
+		reply = sctp_make_shutdown(asoc, NULL);
+		break;
+
+	case SCTP_STATE_SHUTDOWN_ACK_SENT:
+		reply = sctp_make_shutdown_ack(asoc, NULL);
+		break;
+
+	default:
+		BUG();
+		break;
+	}
+
+	if (!reply)
+		goto nomem;
+
+	/* Do some failure management (Section 8.2).
+	 * If we remove the transport an SHUTDOWN was last sent to, don't
+	 * do failure management.
+	 */
+	if (asoc->shutdown_last_sent_to)
+		sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
+				SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
+
+	/* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
+	 * the T2-shutdown timer.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
+
+	/* Restart the T2-shutdown timer.  */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+	return SCTP_DISPOSITION_CONSUME;
+
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/*
+ * ADDIP Section 4.1 ASCONF CHunk Procedures
+ * If the T4 RTO timer expires the endpoint should do B1 to B5
+ */
+enum sctp_disposition sctp_sf_t4_timer_expire(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *chunk = asoc->addip_last_asconf;
+	struct sctp_transport *transport = chunk->transport;
+
+	SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
+
+	/* ADDIP 4.1 B1) Increment the error counters and perform path failure
+	 * detection on the appropriate destination address as defined in
+	 * RFC2960 [5] section 8.1 and 8.2.
+	 */
+	if (transport)
+		sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
+				SCTP_TRANSPORT(transport));
+
+	/* Reconfig T4 timer and transport. */
+	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
+
+	/* ADDIP 4.1 B2) Increment the association error counters and perform
+	 * endpoint failure detection on the association as defined in
+	 * RFC2960 [5] section 8.1 and 8.2.
+	 * association error counter is incremented in SCTP_CMD_STRIKE.
+	 */
+	if (asoc->overall_error_count >= asoc->max_retrans) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
+				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ETIMEDOUT));
+		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+				SCTP_PERR(SCTP_ERROR_NO_ERROR));
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		return SCTP_DISPOSITION_ABORT;
+	}
+
+	/* ADDIP 4.1 B3) Back-off the destination address RTO value to which
+	 * the ASCONF chunk was sent by doubling the RTO timer value.
+	 * This is done in SCTP_CMD_STRIKE.
+	 */
+
+	/* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
+	 * choose an alternate destination address (please refer to RFC2960
+	 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
+	 * chunk, it MUST be the same (including its serial number) as the last
+	 * ASCONF sent.
+	 */
+	sctp_chunk_hold(asoc->addip_last_asconf);
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+			SCTP_CHUNK(asoc->addip_last_asconf));
+
+	/* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
+	 * destination is selected, then the RTO used will be that of the new
+	 * destination address.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
+			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/* sctpimpguide-05 Section 2.12.2
+ * The sender of the SHUTDOWN MAY also start an overall guard timer
+ * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
+ * At the expiration of this timer the sender SHOULD abort the association
+ * by sending an ABORT chunk.
+ */
+enum sctp_disposition sctp_sf_t5_timer_expire(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	struct sctp_chunk *reply = NULL;
+
+	pr_debug("%s: timer T5 expired\n", __func__);
+
+	SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
+
+	reply = sctp_make_abort(asoc, NULL, 0);
+	if (!reply)
+		goto nomem;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+			SCTP_ERROR(ETIMEDOUT));
+	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+			SCTP_PERR(SCTP_ERROR_NO_ERROR));
+
+	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+
+	return SCTP_DISPOSITION_DELETE_TCB;
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
+}
+
+/* Handle expiration of AUTOCLOSE timer.  When the autoclose timer expires,
+ * the association is automatically closed by starting the shutdown process.
+ * The work that needs to be done is same as when SHUTDOWN is initiated by
+ * the user.  So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
+ */
+enum sctp_disposition sctp_sf_autoclose_timer_expire(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const union sctp_subtype type,
+					void *arg,
+					struct sctp_cmd_seq *commands)
+{
+	enum sctp_disposition disposition;
+
+	SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
+
+	/* From 9.2 Shutdown of an Association
+	 * Upon receipt of the SHUTDOWN primitive from its upper
+	 * layer, the endpoint enters SHUTDOWN-PENDING state and
+	 * remains there until all outstanding data has been
+	 * acknowledged by its peer. The endpoint accepts no new data
+	 * from its upper layer, but retransmits data to the far end
+	 * if necessary to fill gaps.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
+
+	disposition = SCTP_DISPOSITION_CONSUME;
+	if (sctp_outq_is_empty(&asoc->outqueue)) {
+		disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
+							    NULL, commands);
+	}
+
+	return disposition;
+}
+
+/*****************************************************************************
+ * These are sa state functions which could apply to all types of events.
+ ****************************************************************************/
+
+/*
+ * This table entry is not implemented.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_not_impl(struct net *net,
+				       const struct sctp_endpoint *ep,
+				       const struct sctp_association *asoc,
+				       const union sctp_subtype type,
+				       void *arg, struct sctp_cmd_seq *commands)
+{
+	return SCTP_DISPOSITION_NOT_IMPL;
+}
+
+/*
+ * This table entry represents a bug.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_bug(struct net *net,
+				  const struct sctp_endpoint *ep,
+				  const struct sctp_association *asoc,
+				  const union sctp_subtype type,
+				  void *arg, struct sctp_cmd_seq *commands)
+{
+	return SCTP_DISPOSITION_BUG;
+}
+
+/*
+ * This table entry represents the firing of a timer in the wrong state.
+ * Since timer deletion cannot be guaranteed a timer 'may' end up firing
+ * when the association is in the wrong state.   This event should
+ * be ignored, so as to prevent any rearming of the timer.
+ *
+ * Inputs
+ * (endpoint, asoc, chunk)
+ *
+ * The return value is the disposition of the chunk.
+ */
+enum sctp_disposition sctp_sf_timer_ignore(struct net *net,
+					   const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const union sctp_subtype type,
+					   void *arg,
+					   struct sctp_cmd_seq *commands)
+{
+	pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
+/********************************************************************
+ * 2nd Level Abstractions
+ ********************************************************************/
+
+/* Pull the SACK chunk based on the SACK header. */
+static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
+{
+	struct sctp_sackhdr *sack;
+	__u16 num_dup_tsns;
+	unsigned int len;
+	__u16 num_blocks;
+
+	/* Protect ourselves from reading too far into
+	 * the skb from a bogus sender.
+	 */
+	sack = (struct sctp_sackhdr *) chunk->skb->data;
+
+	num_blocks = ntohs(sack->num_gap_ack_blocks);
+	num_dup_tsns = ntohs(sack->num_dup_tsns);
+	len = sizeof(struct sctp_sackhdr);
+	len += (num_blocks + num_dup_tsns) * sizeof(__u32);
+	if (len > chunk->skb->len)
+		return NULL;
+
+	skb_pull(chunk->skb, len);
+
+	return sack;
+}
+
+/* Create an ABORT packet to be sent as a response, with the specified
+ * error causes.
+ */
+static struct sctp_packet *sctp_abort_pkt_new(
+					struct net *net,
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					struct sctp_chunk *chunk,
+					const void *payload, size_t paylen)
+{
+	struct sctp_packet *packet;
+	struct sctp_chunk *abort;
+
+	packet = sctp_ootb_pkt_new(net, asoc, chunk);
+
+	if (packet) {
+		/* Make an ABORT.
+		 * The T bit will be set if the asoc is NULL.
+		 */
+		abort = sctp_make_abort(asoc, chunk, paylen);
+		if (!abort) {
+			sctp_ootb_pkt_free(packet);
+			return NULL;
+		}
+
+		/* Reflect vtag if T-Bit is set */
+		if (sctp_test_T_bit(abort))
+			packet->vtag = ntohl(chunk->sctp_hdr->vtag);
+
+		/* Add specified error causes, i.e., payload, to the
+		 * end of the chunk.
+		 */
+		sctp_addto_chunk(abort, paylen, payload);
+
+		/* Set the skb to the belonging sock for accounting.  */
+		abort->skb->sk = ep->base.sk;
+
+		sctp_packet_append_chunk(packet, abort);
+
+	}
+
+	return packet;
+}
+
+/* Allocate a packet for responding in the OOTB conditions.  */
+static struct sctp_packet *sctp_ootb_pkt_new(
+					struct net *net,
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk)
+{
+	struct sctp_transport *transport;
+	struct sctp_packet *packet;
+	__u16 sport, dport;
+	__u32 vtag;
+
+	/* Get the source and destination port from the inbound packet.  */
+	sport = ntohs(chunk->sctp_hdr->dest);
+	dport = ntohs(chunk->sctp_hdr->source);
+
+	/* The V-tag is going to be the same as the inbound packet if no
+	 * association exists, otherwise, use the peer's vtag.
+	 */
+	if (asoc) {
+		/* Special case the INIT-ACK as there is no peer's vtag
+		 * yet.
+		 */
+		switch (chunk->chunk_hdr->type) {
+		case SCTP_CID_INIT:
+		case SCTP_CID_INIT_ACK:
+		{
+			struct sctp_initack_chunk *initack;
+
+			initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
+			vtag = ntohl(initack->init_hdr.init_tag);
+			break;
+		}
+		default:
+			vtag = asoc->peer.i.init_tag;
+			break;
+		}
+	} else {
+		/* Special case the INIT and stale COOKIE_ECHO as there is no
+		 * vtag yet.
+		 */
+		switch (chunk->chunk_hdr->type) {
+		case SCTP_CID_INIT:
+		{
+			struct sctp_init_chunk *init;
+
+			init = (struct sctp_init_chunk *)chunk->chunk_hdr;
+			vtag = ntohl(init->init_hdr.init_tag);
+			break;
+		}
+		default:
+			vtag = ntohl(chunk->sctp_hdr->vtag);
+			break;
+		}
+	}
+
+	/* Make a transport for the bucket, Eliza... */
+	transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
+	if (!transport)
+		goto nomem;
+
+	/* Cache a route for the transport with the chunk's destination as
+	 * the source address.
+	 */
+	sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
+			     sctp_sk(net->sctp.ctl_sock));
+
+	packet = &transport->packet;
+	sctp_packet_init(packet, transport, sport, dport);
+	sctp_packet_config(packet, vtag, 0);
+
+	return packet;
+
+nomem:
+	return NULL;
+}
+
+/* Free the packet allocated earlier for responding in the OOTB condition.  */
+void sctp_ootb_pkt_free(struct sctp_packet *packet)
+{
+	sctp_transport_free(packet->transport);
+}
+
+/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found  */
+static void sctp_send_stale_cookie_err(struct net *net,
+				       const struct sctp_endpoint *ep,
+				       const struct sctp_association *asoc,
+				       const struct sctp_chunk *chunk,
+				       struct sctp_cmd_seq *commands,
+				       struct sctp_chunk *err_chunk)
+{
+	struct sctp_packet *packet;
+
+	if (err_chunk) {
+		packet = sctp_ootb_pkt_new(net, asoc, chunk);
+		if (packet) {
+			struct sctp_signed_cookie *cookie;
+
+			/* Override the OOTB vtag from the cookie. */
+			cookie = chunk->subh.cookie_hdr;
+			packet->vtag = cookie->c.peer_vtag;
+
+			/* Set the skb to the belonging sock for accounting. */
+			err_chunk->skb->sk = ep->base.sk;
+			sctp_packet_append_chunk(packet, err_chunk);
+			sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
+					SCTP_PACKET(packet));
+			SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+		} else
+			sctp_chunk_free (err_chunk);
+	}
+}
+
+
+/* Process a data chunk */
+static int sctp_eat_data(const struct sctp_association *asoc,
+			 struct sctp_chunk *chunk,
+			 struct sctp_cmd_seq *commands)
+{
+	struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
+	struct sock *sk = asoc->base.sk;
+	struct net *net = sock_net(sk);
+	struct sctp_datahdr *data_hdr;
+	struct sctp_chunk *err;
+	enum sctp_verb deliver;
+	size_t datalen;
+	__u32 tsn;
+	int tmp;
+
+	data_hdr = (struct sctp_datahdr *)chunk->skb->data;
+	chunk->subh.data_hdr = data_hdr;
+	skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream));
+
+	tsn = ntohl(data_hdr->tsn);
+	pr_debug("%s: TSN 0x%x\n", __func__, tsn);
+
+	/* ASSERT:  Now skb->data is really the user data.  */
+
+	/* Process ECN based congestion.
+	 *
+	 * Since the chunk structure is reused for all chunks within
+	 * a packet, we use ecn_ce_done to track if we've already
+	 * done CE processing for this packet.
+	 *
+	 * We need to do ECN processing even if we plan to discard the
+	 * chunk later.
+	 */
+
+	if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) {
+		struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
+		chunk->ecn_ce_done = 1;
+
+		if (af->is_ce(sctp_gso_headskb(chunk->skb))) {
+			/* Do real work as sideffect. */
+			sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
+					SCTP_U32(tsn));
+		}
+	}
+
+	tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
+	if (tmp < 0) {
+		/* The TSN is too high--silently discard the chunk and
+		 * count on it getting retransmitted later.
+		 */
+		if (chunk->asoc)
+			chunk->asoc->stats.outofseqtsns++;
+		return SCTP_IERROR_HIGH_TSN;
+	} else if (tmp > 0) {
+		/* This is a duplicate.  Record it.  */
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
+		return SCTP_IERROR_DUP_TSN;
+	}
+
+	/* This is a new TSN.  */
+
+	/* Discard if there is no room in the receive window.
+	 * Actually, allow a little bit of overflow (up to a MTU).
+	 */
+	datalen = ntohs(chunk->chunk_hdr->length);
+	datalen -= sctp_datachk_len(&asoc->stream);
+
+	deliver = SCTP_CMD_CHUNK_ULP;
+
+	/* Think about partial delivery. */
+	if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
+
+		/* Even if we don't accept this chunk there is
+		 * memory pressure.
+		 */
+		sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
+	}
+
+	/* Spill over rwnd a little bit.  Note: While allowed, this spill over
+	 * seems a bit troublesome in that frag_point varies based on
+	 * PMTU.  In cases, such as loopback, this might be a rather
+	 * large spill over.
+	 */
+	if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
+	    (datalen > asoc->rwnd + asoc->frag_point))) {
+
+		/* If this is the next TSN, consider reneging to make
+		 * room.   Note: Playing nice with a confused sender.  A
+		 * malicious sender can still eat up all our buffer
+		 * space and in the future we may want to detect and
+		 * do more drastic reneging.
+		 */
+		if (sctp_tsnmap_has_gap(map) &&
+		    (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
+			pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
+			deliver = SCTP_CMD_RENEGE;
+		} else {
+			pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
+				 __func__, tsn, datalen, asoc->rwnd);
+
+			return SCTP_IERROR_IGNORE_TSN;
+		}
+	}
+
+	/*
+	 * Also try to renege to limit our memory usage in the event that
+	 * we are under memory pressure
+	 * If we can't renege, don't worry about it, the sk_rmem_schedule
+	 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
+	 * memory usage too much
+	 */
+	if (sk_under_memory_pressure(sk)) {
+		if (sctp_tsnmap_has_gap(map) &&
+		    (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
+			pr_debug("%s: under pressure, reneging for tsn:%u\n",
+				 __func__, tsn);
+			deliver = SCTP_CMD_RENEGE;
+		} else {
+			sk_mem_reclaim(sk);
+		}
+	}
+
+	/*
+	 * Section 3.3.10.9 No User Data (9)
+	 *
+	 * Cause of error
+	 * ---------------
+	 * No User Data:  This error cause is returned to the originator of a
+	 * DATA chunk if a received DATA chunk has no user data.
+	 */
+	if (unlikely(0 == datalen)) {
+		err = sctp_make_abort_no_data(asoc, chunk, tsn);
+		if (err) {
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+					SCTP_CHUNK(err));
+		}
+		/* We are going to ABORT, so we might as well stop
+		 * processing the rest of the chunks in the packet.
+		 */
+		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ECONNABORTED));
+		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+				SCTP_PERR(SCTP_ERROR_NO_DATA));
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		return SCTP_IERROR_NO_DATA;
+	}
+
+	chunk->data_accepted = 1;
+
+	/* Note: Some chunks may get overcounted (if we drop) or overcounted
+	 * if we renege and the chunk arrives again.
+	 */
+	if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
+		SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
+		if (chunk->asoc)
+			chunk->asoc->stats.iuodchunks++;
+	} else {
+		SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
+		if (chunk->asoc)
+			chunk->asoc->stats.iodchunks++;
+	}
+
+	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
+	 *
+	 * If an endpoint receive a DATA chunk with an invalid stream
+	 * identifier, it shall acknowledge the reception of the DATA chunk
+	 * following the normal procedure, immediately send an ERROR chunk
+	 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
+	 * and discard the DATA chunk.
+	 */
+	if (ntohs(data_hdr->stream) >= asoc->stream.incnt) {
+		/* Mark tsn as received even though we drop it */
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
+
+		err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
+					 &data_hdr->stream,
+					 sizeof(data_hdr->stream),
+					 sizeof(u16));
+		if (err)
+			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+					SCTP_CHUNK(err));
+		return SCTP_IERROR_BAD_STREAM;
+	}
+
+	/* Check to see if the SSN is possible for this TSN.
+	 * The biggest gap we can record is 4K wide.  Since SSNs wrap
+	 * at an unsigned short, there is no way that an SSN can
+	 * wrap and for a valid TSN.  We can simply check if the current
+	 * SSN is smaller then the next expected one.  If it is, it wrapped
+	 * and is invalid.
+	 */
+	if (!asoc->stream.si->validate_data(chunk))
+		return SCTP_IERROR_PROTO_VIOLATION;
+
+	/* Send the data up to the user.  Note:  Schedule  the
+	 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
+	 * chunk needs the updated rwnd.
+	 */
+	sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
+
+	return SCTP_IERROR_NO_ERROR;
+}