/* 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.
   *

   * This SCTP implementation is free software;

   * you can redistribute it and/or modify it under the terms of
   * the GNU General Public License as published by
   * the Free Software Foundation; either version 2, or (at your option)
   * any later version.
   *

   * This SCTP implementation is distributed in the hope that it

   * will be useful, but WITHOUT ANY WARRANTY; without even the implied
   *                 ************************
   * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   * See the GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with GNU CC; see the file COPYING.  If not, write to
   * the Free Software Foundation, 59 Temple Place - Suite 330,
   * Boston, MA 02111-1307, USA.
   *
   * Please send any bug reports or fixes you make to the
   * email address(es):
   *    lksctp developers <lksctp-developers@lists.sourceforge.net>
   *
   * Or submit a bug report through the following website:
   *    http://www.sf.net/projects/lksctp
   *
   * Written or modified by:
   *    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>
   *
   * Any bugs reported given to us we will try to fix... any fixes shared will
   * be incorporated into the next SCTP release.
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/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>

  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,
  			 sctp_cmd_seq_t *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,
  				       sctp_cmd_seq_t *commands,
  				       struct sctp_chunk *err_chunk);

  static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
  						 const struct sctp_endpoint *ep,

  						 const struct sctp_association *asoc,
  						 const sctp_subtype_t type,
  						 void *arg,
  						 sctp_cmd_seq_t *commands);

  static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net,
  					     const struct sctp_endpoint *ep,

  					     const struct sctp_association *asoc,
  					     const sctp_subtype_t type,
  					     void *arg,
  					     sctp_cmd_seq_t *commands);

  static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *commands);

  static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);

  static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
  					   sctp_cmd_seq_t *commands,

  					   __be16 error, int sk_err,

  					   const struct sctp_association *asoc,
  					   struct sctp_transport *transport);

  static sctp_disposition_t sctp_sf_abort_violation(

  				     struct net *net,

  				     const struct sctp_endpoint *ep,

  				     const struct sctp_association *asoc,
  				     void *arg,
  				     sctp_cmd_seq_t *commands,
  				     const __u8 *payload,
  				     const size_t paylen);

  static sctp_disposition_t sctp_sf_violation_chunklen(

  				     struct net *net,

  				     const struct sctp_endpoint *ep,
  				     const struct sctp_association *asoc,
  				     const sctp_subtype_t type,
  				     void *arg,
  				     sctp_cmd_seq_t *commands);

  static sctp_disposition_t sctp_sf_violation_paramlen(

  				     struct net *net,

  				     const struct sctp_endpoint *ep,
  				     const struct sctp_association *asoc,
  				     const sctp_subtype_t type,

  				     void *arg, void *ext,

  				     sctp_cmd_seq_t *commands);

  static sctp_disposition_t sctp_sf_violation_ctsn(

  				     struct net *net,

  				     const struct sctp_endpoint *ep,
  				     const struct sctp_association *asoc,
  				     const sctp_subtype_t type,
  				     void *arg,
  				     sctp_cmd_seq_t *commands);

  static sctp_disposition_t sctp_sf_violation_chunk(

  				     struct net *net,

  				     const struct sctp_endpoint *ep,
  				     const struct sctp_association *asoc,
  				     const sctp_subtype_t type,
  				     void *arg,
  				     sctp_cmd_seq_t *commands);

  static sctp_ierror_t sctp_sf_authenticate(struct net *net,
  				    const struct sctp_endpoint *ep,

  				    const struct sctp_association *asoc,
  				    const sctp_subtype_t type,
  				    struct sctp_chunk *chunk);

  static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *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:  1 = Valid length
   * 		   0 = Invalid length
   *
   */
  static inline int
  sctp_chunk_length_valid(struct sctp_chunk *chunk,
  			   __u16 required_length)
  {
  	__u16 chunk_length = ntohs(chunk->chunk_hdr->length);
  
  	if (unlikely(chunk_length < required_length))
  		return 0;
  
  	return 1;
  }
  
  /**********************************************************
   * 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.
   */

  sctp_disposition_t sctp_sf_do_4_C(struct net *net,
  				  const struct sctp_endpoint *ep,

  				  const struct sctp_association *asoc,
  				  const sctp_subtype_t type,
  				  void *arg,
  				  sctp_cmd_seq_t *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(sctp_chunkhdr_t)))

  		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.
   */

  sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;
  	struct sctp_chunk *repl;
  	struct sctp_association *new_asoc;
  	struct sctp_chunk *err_chunk;
  	struct sctp_packet *packet;
  	sctp_unrecognized_param_t *unk_param;

  	int len;
  
  	/* 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);

  
  	/* 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);

  
  	/* 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(sctp_init_chunk_t)))

  		return sctp_sf_pdiscard(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, asoc, chunk->chunk_hdr->type,

  			      (sctp_init_chunk_t *)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(sctp_chunkhdr_t),
  					ntohs(err_chunk->chunk_hdr->length) -
  					sizeof(sctp_chunkhdr_t));
  
  			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 = (sctp_inithdr_t *)chunk->skb->data;
  
  	/* Tag the variable length parameters.  */
  	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
  
  	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),

  			       (sctp_init_chunk_t *)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(sctp_chunkhdr_t);

  	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 = (sctp_unrecognized_param_t *)
  			    ((__u8 *)(err_chunk->chunk_hdr) +
  			    sizeof(sctp_chunkhdr_t));
  		/* 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.
   */

  sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net,
  				       const struct sctp_endpoint *ep,

  				       const struct sctp_association *asoc,
  				       const sctp_subtype_t type,
  				       void *arg,
  				       sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;
  	sctp_init_chunk_t *initchunk;

  	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(sctp_initack_chunk_t)))

  		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,

  						  commands);

  	/* Grab the INIT header.  */
  	chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;

  	/* Verify the INIT chunk before processing it. */
  	err_chunk = NULL;

  	if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type,

  			      (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
  			      &err_chunk)) {

  		sctp_error_t 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(sctp_chunkhdr_t),
  					ntohs(err_chunk->chunk_hdr->length) -
  					sizeof(sctp_chunkhdr_t));
  
  			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(sctp_inithdr_t));
  
  	initchunk = (sctp_init_chunk_t *) 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;

  }
  
  /*
   * 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.
   */

  sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net,
  				      const struct sctp_endpoint *ep,

  				      const struct sctp_association *asoc,
  				      const sctp_subtype_t type, void *arg,
  				      sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;
  	struct sctp_association *new_asoc;
  	sctp_init_chunk_t *peer_init;
  	struct sctp_chunk *repl;

  	struct sctp_ulpevent *ev, *ai_ev = NULL;

  	int error = 0;
  	struct sctp_chunk *err_chk_p;

  	struct sock *sk;

  
  	/* 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(sctp_chunkhdr_t)))

  		return sctp_sf_pdiscard(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(sctp_chunkhdr_t)))
  		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;

  	/* 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.
  	 */
  	if (chunk->auth_chunk) {
  		struct sctp_chunk auth;
  		sctp_ierror_t ret;
  
  		/* 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 = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
  					    sizeof(sctp_chunkhdr_t));
  		skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
  		auth.transport = chunk->transport;

  		ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth);

  
  		/* We can now safely free the auth_chunk clone */
  		kfree_skb(chunk->auth_chunk);
  
  		if (ret != SCTP_IERROR_NO_ERROR) {
  			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;
  	}
  
  	/* 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->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));

  
  	return SCTP_DISPOSITION_CONSUME;

  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 being asked 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.
   */

  sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net,
  				      const struct sctp_endpoint *ep,

  				      const struct sctp_association *asoc,
  				      const sctp_subtype_t type, void *arg,
  				      sctp_cmd_seq_t *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(sctp_chunkhdr_t)))

  		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());

  
  	/* 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->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));
  	}
  
  	return SCTP_DISPOSITION_CONSUME;
  nomem:
  	return SCTP_DISPOSITION_NOMEM;
  }
  
  /* Generate and sendout a heartbeat packet.  */
  static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
  					    const struct sctp_association *asoc,
  					    const sctp_subtype_t type,
  					    void *arg,
  					    sctp_cmd_seq_t *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.  */

  sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *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;

  }
  
  /*
   * 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.
   */

  sctp_disposition_t sctp_sf_beat_8_3(struct net *net,
  				    const struct sctp_endpoint *ep,

  				    const struct sctp_association *asoc,
  				    const sctp_subtype_t type,
  				    void *arg,
  				    sctp_cmd_seq_t *commands)
  {

  	sctp_paramhdr_t *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(sctp_heartbeat_chunk_t)))

  		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 = (sctp_heartbeathdr_t *) chunk->skb->data;

  	param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr;

  	paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);

  
  	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.
   */

  sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;
  	union sctp_addr from_addr;
  	struct sctp_transport *link;
  	sctp_sender_hb_info_t *hbinfo;
  	unsigned long max_interval;
  
  	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(sctp_chunkhdr_t) +
  					    sizeof(sctp_sender_hb_info_t)))

  		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,

  						  commands);
  
  	hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;

  	/* Make sure that the length of the parameter is what we expect */
  	if (ntohs(hbinfo->param_hdr.length) !=
  				    sizeof(sctp_sender_hb_info_t)) {
  		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
  ",
  					     __func__,
  					     asoc,
  					     &from_addr.v6.sin6_addr);

  		} else {

  			net_warn_ratelimited("%s association %p could not find address %pI4
  ",
  					     __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)) {

  		SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp "

  				  "received for transport: %p
  ",

  				   __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,
  				      sctp_cmd_seq_t *commands)
  {
  	int len;
  	struct sctp_packet *pkt;
  	union sctp_addr_param *addrparm;
  	struct sctp_errhdr *errhdr;
  	struct sctp_endpoint *ep;
  	char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
  	struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
  
  	/* 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(sctp_errhdr_t);
  
  	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,
  				       sctp_cmd_seq_t *commands)
  {

  	struct net *net = sock_net(new_asoc->base.sk);

  	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 sctp_disposition_t sctp_sf_do_unexpected_init(

  	struct net *net,

  	const struct sctp_endpoint *ep,
  	const struct sctp_association *asoc,
  	const sctp_subtype_t type,
  	void *arg, sctp_cmd_seq_t *commands)
  {
  	sctp_disposition_t retval;
  	struct sctp_chunk *chunk = arg;
  	struct sctp_chunk *repl;
  	struct sctp_association *new_asoc;
  	struct sctp_chunk *err_chunk;
  	struct sctp_packet *packet;
  	sctp_unrecognized_param_t *unk_param;
  	int len;
  
  	/* 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);

  
  	/* 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);

  
  	/* Make sure that the INIT chunk has a valid length.
  	 * In this case, we generate a protocol violation since we have
  	 * an association established.
  	 */
  	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))

  		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,

  						  commands);
  	/* Grab the INIT header.  */
  	chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
  
  	/* Tag the variable length parameters.  */
  	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
  
  	/* Verify the INIT chunk before processing it. */
  	err_chunk = NULL;

  	if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type,

  			      (sctp_init_chunk_t *)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(sctp_chunkhdr_t),
  					ntohs(err_chunk->chunk_hdr->length) -
  					sizeof(sctp_chunkhdr_t));
  
  			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),

  			       (sctp_init_chunk_t *)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(sctp_chunkhdr_t);
  	}

  	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 = (sctp_unrecognized_param_t *)
  			    ((__u8 *)(err_chunk->chunk_hdr) +
  			    sizeof(sctp_chunkhdr_t));
  		/* 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.
   */

  sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net,
  				    const struct sctp_endpoint *ep,

  				    const struct sctp_association *asoc,
  				    const sctp_subtype_t type,
  				    void *arg,
  				    sctp_cmd_seq_t *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.
   */

  sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *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.
  */

  sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net,
  					    const struct sctp_endpoint *ep,

  					    const struct sctp_association *asoc,
  					    const sctp_subtype_t type,
  					    void *arg, sctp_cmd_seq_t *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 sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					struct sctp_chunk *chunk,
  					sctp_cmd_seq_t *commands,
  					struct sctp_association *new_asoc)
  {
  	sctp_init_chunk_t *peer_init;
  	struct sctp_ulpevent *ev;
  	struct sctp_chunk *repl;
  	struct sctp_chunk *err;
  	sctp_disposition_t disposition;
  
  	/* 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;
  
  	/* 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());

  	repl = sctp_make_cookie_ack(new_asoc, chunk);
  	if (!repl)
  		goto nomem;

  	/* Report association restart to upper layer. */
  	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
  					     new_asoc->c.sinit_num_ostreams,
  					     new_asoc->c.sinit_max_instreams,

  					     NULL, GFP_ATOMIC);

  	if (!ev)
  		goto nomem_ev;

  	/* 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_EVENT_ULP, SCTP_ULPEVENT(ev));

  	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 sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					struct sctp_chunk *chunk,
  					sctp_cmd_seq_t *commands,
  					struct sctp_association *new_asoc)
  {
  	sctp_init_chunk_t *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;
  
  	/* 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));

  	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());

  
  	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 sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					struct sctp_chunk *chunk,
  					sctp_cmd_seq_t *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 sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					struct sctp_chunk *chunk,
  					sctp_cmd_seq_t *commands,
  					struct sctp_association *new_asoc)
  {

  	struct sctp_ulpevent *ev = NULL, *ai_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.

  	 */
  
  	/* 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;

  		}
  	}

  
  	repl = sctp_make_cookie_ack(new_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));

  	return SCTP_DISPOSITION_CONSUME;
  
  nomem:

  	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.
   */

  sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *commands)
  {
  	sctp_disposition_t retval;
  	struct sctp_chunk *chunk = arg;
  	struct sctp_association *new_asoc;
  	int error = 0;
  	char action;
  	struct sctp_chunk *err_chk_p;
  
  	/* 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(sctp_chunkhdr_t)))

  		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(sctp_chunkhdr_t)))
  		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);

  		}

  	}
  
  	/* 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().
   */
  sctp_disposition_t sctp_sf_shutdown_pending_abort(

  	struct net *net,

  	const struct sctp_endpoint *ep,
  	const struct sctp_association *asoc,
  	const sctp_subtype_t type,
  	void *arg,
  	sctp_cmd_seq_t *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(sctp_abort_chunk_t)))

  		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_discard_chunk(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().
   */

  sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *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(sctp_abort_chunk_t)))

  		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_discard_chunk(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().
   */
  sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(

  	struct net *net,

  	const struct sctp_endpoint *ep,
  	const struct sctp_association *asoc,
  	const sctp_subtype_t type,
  	void *arg,
  	sctp_cmd_seq_t *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.
   */

  sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;
  	sctp_errhdr_t *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(sctp_operr_chunk_t)))

  		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 sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
  						 const struct sctp_endpoint *ep,

  						 const struct sctp_association *asoc,
  						 const sctp_subtype_t type,
  						 void *arg,
  						 sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;
  	time_t stale;
  	sctp_cookie_preserve_param_t bht;
  	sctp_errhdr_t *err;
  	struct sctp_chunk *reply;
  	struct sctp_bind_addr *bp;

  	int attempts = asoc->init_err_counter + 1;

  	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 = (sctp_errhdr_t *)(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(sctp_errhdr_t)));

  	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.
   */

  sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *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(sctp_abort_chunk_t)))

  		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_discard_chunk(net, ep, asoc, type, arg, commands);

  	return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);

  }

  static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;

  	unsigned int len;

  	__be16 error = SCTP_ERROR_NO_ERROR;

  	/* 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)) {
  
  		sctp_errhdr_t *err;
  		sctp_walk_errors(err, chunk->chunk_hdr);
  		if ((void *)err != (void *)chunk->chunk_end)

  			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);

  		error = ((sctp_errhdr_t *)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.
   */

  sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net,
  				     const struct sctp_endpoint *ep,

  				     const struct sctp_association *asoc,
  				     const sctp_subtype_t type,
  				     void *arg,
  				     sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;

  	unsigned int len;

  	__be16 error = SCTP_ERROR_NO_ERROR;

  
  	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(sctp_abort_chunk_t)))

  		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 = ((sctp_errhdr_t *)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)
   */

  sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net,
  					const struct sctp_endpoint *ep,

  					const struct sctp_association *asoc,
  					const sctp_subtype_t type,
  					void *arg,
  					sctp_cmd_seq_t *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)
   */

  sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net,
  					       const struct sctp_endpoint *ep,

  					       const struct sctp_association *asoc,
  					       const sctp_subtype_t type,
  					       void *arg,
  					       sctp_cmd_seq_t *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 sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
  					   sctp_cmd_seq_t *commands,

  					   __be16 error, int sk_err,

  					   const struct sctp_association *asoc,
  					   struct sctp_transport *transport)

  {

  	SCTP_DEBUG_PRINTK("ABORT received (INIT).
  ");

  	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.
   */

  sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net,
  					   const struct sctp_endpoint *ep,

  					   const struct sctp_association *asoc,
  					   const sctp_subtype_t type,
  					   void *arg,
  					   sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;
  	sctp_shutdownhdr_t *sdh;
  	sctp_disposition_t disposition;
  	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_t)))

  		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,

  						  commands);
  
  	/* Convert the elaborate header.  */
  	sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
  	skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
  	chunk->subh.shutdown_hdr = sdh;

  	ctsn = ntohl(sdh->cum_tsn_ack);

  	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
  		SCTP_DEBUG_PRINTK("ctsn %x
  ", ctsn);
  		SCTP_DEBUG_PRINTK("ctsn_ack_point %x
  ", 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.
   */

  sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net,
  					   const struct sctp_endpoint *ep,

  					   const struct sctp_association *asoc,
  					   const sctp_subtype_t type,
  					   void *arg,
  					   sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = arg;
  	sctp_shutdownhdr_t *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_t)))

  		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,

  						  commands);
  
  	sdh = (sctp_shutdownhdr_t *)chunk->skb->data;

  	ctsn = ntohl(sdh->cum_tsn_ack);
  
  	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
  		SCTP_DEBUG_PRINTK("ctsn %x
  ", ctsn);
  		SCTP_DEBUG_PRINTK("ctsn_ack_point %x
  ", 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.
   */

  sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net,
  				    const struct sctp_endpoint *ep,

  				    const struct sctp_association *asoc,
  				    const sctp_subtype_t type,
  				    void *arg,
  				    sctp_cmd_seq_t *commands)
  {
  	struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
  	struct sctp_chunk *reply;

  	/* Make sure that the chunk has a valid length */
  	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))

  		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;
  }
  
  /*
   * 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.
   */

  sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net,
  				      const struct sctp_endpoint *ep,

  				      const struct sctp_association *asoc,
  				      const sctp_subtype_t type,
  				      void *arg,
  				      sctp_cmd_seq_t *commands)
  {
  	sctp_cwrhdr_t *cwr;
  	struct sctp_chunk *chunk = arg;

  	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(sctp_ecne_chunk_t)))

  		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,

  						  commands);

  	cwr = (sctp_cwrhdr_t *) chunk->skb->data;
  	skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));

  	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,