Adding upstream version 5.10.209.upstream/5.10.209upstream

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

1 files changed, 3891 insertions, 0 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
new file mode 100644
index 000000000..64e0f4864
--- /dev/null
+++ b/net/sctp/sm_make_chunk.c
@@ -0,0 +1,3891 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* SCTP kernel implementation
+ * (C) Copyright IBM Corp. 2001, 2004
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001-2002 Intel Corp.
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * These functions work with the state functions in sctp_sm_statefuns.c
+ * to implement the state operations.  These functions implement the
+ * steps which require modifying existing data structures.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email address(es):
+ *    lksctp developers <linux-sctp@vger.kernel.org>
+ *
+ * Written or modified by:
+ *    La Monte H.P. Yarroll <piggy@acm.org>
+ *    Karl Knutson          <karl@athena.chicago.il.us>
+ *    C. Robin              <chris@hundredacre.ac.uk>
+ *    Jon Grimm             <jgrimm@us.ibm.com>
+ *    Xingang Guo           <xingang.guo@intel.com>
+ *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
+ *    Sridhar Samudrala	    <sri@us.ibm.com>
+ *    Daisy Chang	    <daisyc@us.ibm.com>
+ *    Ardelle Fan	    <ardelle.fan@intel.com>
+ *    Kevin Gao             <kevin.gao@intel.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <crypto/hash.h>
+#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/scatterlist.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+
+#include <linux/skbuff.h>
+#include <linux/random.h>	/* for get_random_bytes */
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+
+static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
+					    __u8 type, __u8 flags, int paylen,
+					    gfp_t gfp);
+static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
+					 __u8 flags, int paylen, gfp_t gfp);
+static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
+					   __u8 type, __u8 flags, int paylen,
+					   gfp_t gfp);
+static struct sctp_cookie_param *sctp_pack_cookie(
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *init_chunk,
+					int *cookie_len,
+					const __u8 *raw_addrs, int addrs_len);
+static int sctp_process_param(struct sctp_association *asoc,
+			      union sctp_params param,
+			      const union sctp_addr *peer_addr,
+			      gfp_t gfp);
+static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
+			      const void *data);
+
+/* Control chunk destructor */
+static void sctp_control_release_owner(struct sk_buff *skb)
+{
+	struct sctp_chunk *chunk = skb_shinfo(skb)->destructor_arg;
+
+	if (chunk->shkey) {
+		struct sctp_shared_key *shkey = chunk->shkey;
+		struct sctp_association *asoc = chunk->asoc;
+
+		/* refcnt == 2 and !list_empty mean after this release, it's
+		 * not being used anywhere, and it's time to notify userland
+		 * that this shkey can be freed if it's been deactivated.
+		 */
+		if (shkey->deactivated && !list_empty(&shkey->key_list) &&
+		    refcount_read(&shkey->refcnt) == 2) {
+			struct sctp_ulpevent *ev;
+
+			ev = sctp_ulpevent_make_authkey(asoc, shkey->key_id,
+							SCTP_AUTH_FREE_KEY,
+							GFP_KERNEL);
+			if (ev)
+				asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
+		}
+		sctp_auth_shkey_release(chunk->shkey);
+	}
+}
+
+static void sctp_control_set_owner_w(struct sctp_chunk *chunk)
+{
+	struct sctp_association *asoc = chunk->asoc;
+	struct sk_buff *skb = chunk->skb;
+
+	/* TODO: properly account for control chunks.
+	 * To do it right we'll need:
+	 *  1) endpoint if association isn't known.
+	 *  2) proper memory accounting.
+	 *
+	 *  For now don't do anything for now.
+	 */
+	if (chunk->auth) {
+		chunk->shkey = asoc->shkey;
+		sctp_auth_shkey_hold(chunk->shkey);
+	}
+	skb->sk = asoc ? asoc->base.sk : NULL;
+	skb_shinfo(skb)->destructor_arg = chunk;
+	skb->destructor = sctp_control_release_owner;
+}
+
+/* What was the inbound interface for this chunk? */
+int sctp_chunk_iif(const struct sctp_chunk *chunk)
+{
+	struct sk_buff *skb = chunk->skb;
+
+	return SCTP_INPUT_CB(skb)->af->skb_iif(skb);
+}
+
+/* RFC 2960 3.3.2 Initiation (INIT) (1)
+ *
+ * Note 2: The ECN capable field is reserved for future use of
+ * Explicit Congestion Notification.
+ */
+static const struct sctp_paramhdr ecap_param = {
+	SCTP_PARAM_ECN_CAPABLE,
+	cpu_to_be16(sizeof(struct sctp_paramhdr)),
+};
+static const struct sctp_paramhdr prsctp_param = {
+	SCTP_PARAM_FWD_TSN_SUPPORT,
+	cpu_to_be16(sizeof(struct sctp_paramhdr)),
+};
+
+/* A helper to initialize an op error inside a provided chunk, as most
+ * cause codes will be embedded inside an abort chunk.
+ */
+int sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
+		    size_t paylen)
+{
+	struct sctp_errhdr err;
+	__u16 len;
+
+	/* Cause code constants are now defined in network order.  */
+	err.cause = cause_code;
+	len = sizeof(err) + paylen;
+	err.length = htons(len);
+
+	if (skb_tailroom(chunk->skb) < len)
+		return -ENOSPC;
+
+	chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(err), &err);
+
+	return 0;
+}
+
+/* 3.3.2 Initiation (INIT) (1)
+ *
+ * This chunk is used to initiate a SCTP association between two
+ * endpoints. The format of the INIT chunk is shown below:
+ *
+ *     0                   1                   2                   3
+ *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                         Initiate Tag                          |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |           Advertised Receiver Window Credit (a_rwnd)          |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                          Initial TSN                          |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    \                                                               \
+ *    /              Optional/Variable-Length Parameters              /
+ *    \                                                               \
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ *
+ * The INIT chunk contains the following parameters. Unless otherwise
+ * noted, each parameter MUST only be included once in the INIT chunk.
+ *
+ * Fixed Parameters                     Status
+ * ----------------------------------------------
+ * Initiate Tag                        Mandatory
+ * Advertised Receiver Window Credit   Mandatory
+ * Number of Outbound Streams          Mandatory
+ * Number of Inbound Streams           Mandatory
+ * Initial TSN                         Mandatory
+ *
+ * Variable Parameters                  Status     Type Value
+ * -------------------------------------------------------------
+ * IPv4 Address (Note 1)               Optional    5
+ * IPv6 Address (Note 1)               Optional    6
+ * Cookie Preservative                 Optional    9
+ * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
+ * Host Name Address (Note 3)          Optional    11
+ * Supported Address Types (Note 4)    Optional    12
+ */
+struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
+				  const struct sctp_bind_addr *bp,
+				  gfp_t gfp, int vparam_len)
+{
+	struct sctp_supported_ext_param ext_param;
+	struct sctp_adaptation_ind_param aiparam;
+	struct sctp_paramhdr *auth_chunks = NULL;
+	struct sctp_paramhdr *auth_hmacs = NULL;
+	struct sctp_supported_addrs_param sat;
+	struct sctp_endpoint *ep = asoc->ep;
+	struct sctp_chunk *retval = NULL;
+	int num_types, addrs_len = 0;
+	struct sctp_inithdr init;
+	union sctp_params addrs;
+	struct sctp_sock *sp;
+	__u8 extensions[5];
+	size_t chunksize;
+	__be16 types[2];
+	int num_ext = 0;
+
+	/* RFC 2960 3.3.2 Initiation (INIT) (1)
+	 *
+	 * Note 1: The INIT chunks can contain multiple addresses that
+	 * can be IPv4 and/or IPv6 in any combination.
+	 */
+
+	/* Convert the provided bind address list to raw format. */
+	addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
+
+	init.init_tag		   = htonl(asoc->c.my_vtag);
+	init.a_rwnd		   = htonl(asoc->rwnd);
+	init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
+	init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
+	init.initial_tsn	   = htonl(asoc->c.initial_tsn);
+
+	/* How many address types are needed? */
+	sp = sctp_sk(asoc->base.sk);
+	num_types = sp->pf->supported_addrs(sp, types);
+
+	chunksize = sizeof(init) + addrs_len;
+	chunksize += SCTP_PAD4(SCTP_SAT_LEN(num_types));
+
+	if (asoc->ep->ecn_enable)
+		chunksize += sizeof(ecap_param);
+
+	if (asoc->ep->prsctp_enable)
+		chunksize += sizeof(prsctp_param);
+
+	/* ADDIP: Section 4.2.7:
+	 *  An implementation supporting this extension [ADDIP] MUST list
+	 *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
+	 *  INIT-ACK parameters.
+	 */
+	if (asoc->ep->asconf_enable) {
+		extensions[num_ext] = SCTP_CID_ASCONF;
+		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
+		num_ext += 2;
+	}
+
+	if (asoc->ep->reconf_enable) {
+		extensions[num_ext] = SCTP_CID_RECONF;
+		num_ext += 1;
+	}
+
+	if (sp->adaptation_ind)
+		chunksize += sizeof(aiparam);
+
+	if (asoc->ep->intl_enable) {
+		extensions[num_ext] = SCTP_CID_I_DATA;
+		num_ext += 1;
+	}
+
+	chunksize += vparam_len;
+
+	/* Account for AUTH related parameters */
+	if (ep->auth_enable) {
+		/* Add random parameter length*/
+		chunksize += sizeof(asoc->c.auth_random);
+
+		/* Add HMACS parameter length if any were defined */
+		auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
+		if (auth_hmacs->length)
+			chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
+		else
+			auth_hmacs = NULL;
+
+		/* Add CHUNKS parameter length */
+		auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
+		if (auth_chunks->length)
+			chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
+		else
+			auth_chunks = NULL;
+
+		extensions[num_ext] = SCTP_CID_AUTH;
+		num_ext += 1;
+	}
+
+	/* If we have any extensions to report, account for that */
+	if (num_ext)
+		chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
+
+	/* RFC 2960 3.3.2 Initiation (INIT) (1)
+	 *
+	 * Note 3: An INIT chunk MUST NOT contain more than one Host
+	 * Name address parameter. Moreover, the sender of the INIT
+	 * MUST NOT combine any other address types with the Host Name
+	 * address in the INIT. The receiver of INIT MUST ignore any
+	 * other address types if the Host Name address parameter is
+	 * present in the received INIT chunk.
+	 *
+	 * PLEASE DO NOT FIXME [This version does not support Host Name.]
+	 */
+
+	retval = sctp_make_control(asoc, SCTP_CID_INIT, 0, chunksize, gfp);
+	if (!retval)
+		goto nodata;
+
+	retval->subh.init_hdr =
+		sctp_addto_chunk(retval, sizeof(init), &init);
+	retval->param_hdr.v =
+		sctp_addto_chunk(retval, addrs_len, addrs.v);
+
+	/* RFC 2960 3.3.2 Initiation (INIT) (1)
+	 *
+	 * Note 4: This parameter, when present, specifies all the
+	 * address types the sending endpoint can support. The absence
+	 * of this parameter indicates that the sending endpoint can
+	 * support any address type.
+	 */
+	sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
+	sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
+	sctp_addto_chunk(retval, sizeof(sat), &sat);
+	sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
+
+	if (asoc->ep->ecn_enable)
+		sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
+
+	/* Add the supported extensions parameter.  Be nice and add this
+	 * fist before addiding the parameters for the extensions themselves
+	 */
+	if (num_ext) {
+		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
+		ext_param.param_hdr.length = htons(sizeof(ext_param) + num_ext);
+		sctp_addto_chunk(retval, sizeof(ext_param), &ext_param);
+		sctp_addto_param(retval, num_ext, extensions);
+	}
+
+	if (asoc->ep->prsctp_enable)
+		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
+
+	if (sp->adaptation_ind) {
+		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
+		aiparam.param_hdr.length = htons(sizeof(aiparam));
+		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
+		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
+	}
+
+	/* Add SCTP-AUTH chunks to the parameter list */
+	if (ep->auth_enable) {
+		sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
+				 asoc->c.auth_random);
+		if (auth_hmacs)
+			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
+					auth_hmacs);
+		if (auth_chunks)
+			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
+					auth_chunks);
+	}
+nodata:
+	kfree(addrs.v);
+	return retval;
+}
+
+struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
+				      const struct sctp_chunk *chunk,
+				      gfp_t gfp, int unkparam_len)
+{
+	struct sctp_supported_ext_param ext_param;
+	struct sctp_adaptation_ind_param aiparam;
+	struct sctp_paramhdr *auth_chunks = NULL;
+	struct sctp_paramhdr *auth_random = NULL;
+	struct sctp_paramhdr *auth_hmacs = NULL;
+	struct sctp_chunk *retval = NULL;
+	struct sctp_cookie_param *cookie;
+	struct sctp_inithdr initack;
+	union sctp_params addrs;
+	struct sctp_sock *sp;
+	__u8 extensions[5];
+	size_t chunksize;
+	int num_ext = 0;
+	int cookie_len;
+	int addrs_len;
+
+	/* Note: there may be no addresses to embed. */
+	addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
+
+	initack.init_tag	        = htonl(asoc->c.my_vtag);
+	initack.a_rwnd			= htonl(asoc->rwnd);
+	initack.num_outbound_streams	= htons(asoc->c.sinit_num_ostreams);
+	initack.num_inbound_streams	= htons(asoc->c.sinit_max_instreams);
+	initack.initial_tsn		= htonl(asoc->c.initial_tsn);
+
+	/* FIXME:  We really ought to build the cookie right
+	 * into the packet instead of allocating more fresh memory.
+	 */
+	cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
+				  addrs.v, addrs_len);
+	if (!cookie)
+		goto nomem_cookie;
+
+	/* Calculate the total size of allocation, include the reserved
+	 * space for reporting unknown parameters if it is specified.
+	 */
+	sp = sctp_sk(asoc->base.sk);
+	chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
+
+	/* Tell peer that we'll do ECN only if peer advertised such cap.  */
+	if (asoc->peer.ecn_capable)
+		chunksize += sizeof(ecap_param);
+
+	if (asoc->peer.prsctp_capable)
+		chunksize += sizeof(prsctp_param);
+
+	if (asoc->peer.asconf_capable) {
+		extensions[num_ext] = SCTP_CID_ASCONF;
+		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
+		num_ext += 2;
+	}
+
+	if (asoc->peer.reconf_capable) {
+		extensions[num_ext] = SCTP_CID_RECONF;
+		num_ext += 1;
+	}
+
+	if (sp->adaptation_ind)
+		chunksize += sizeof(aiparam);
+
+	if (asoc->peer.intl_capable) {
+		extensions[num_ext] = SCTP_CID_I_DATA;
+		num_ext += 1;
+	}
+
+	if (asoc->peer.auth_capable) {
+		auth_random = (struct sctp_paramhdr *)asoc->c.auth_random;
+		chunksize += ntohs(auth_random->length);
+
+		auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
+		if (auth_hmacs->length)
+			chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
+		else
+			auth_hmacs = NULL;
+
+		auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
+		if (auth_chunks->length)
+			chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
+		else
+			auth_chunks = NULL;
+
+		extensions[num_ext] = SCTP_CID_AUTH;
+		num_ext += 1;
+	}
+
+	if (num_ext)
+		chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
+
+	/* Now allocate and fill out the chunk.  */
+	retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize, gfp);
+	if (!retval)
+		goto nomem_chunk;
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, * etc.) to the same destination transport
+	 * address from which it received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 * [INIT ACK back to where the INIT came from.]
+	 */
+	if (chunk->transport)
+		retval->transport =
+			sctp_assoc_lookup_paddr(asoc,
+						&chunk->transport->ipaddr);
+
+	retval->subh.init_hdr =
+		sctp_addto_chunk(retval, sizeof(initack), &initack);
+	retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
+	sctp_addto_chunk(retval, cookie_len, cookie);
+	if (asoc->peer.ecn_capable)
+		sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
+	if (num_ext) {
+		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
+		ext_param.param_hdr.length = htons(sizeof(ext_param) + num_ext);
+		sctp_addto_chunk(retval, sizeof(ext_param), &ext_param);
+		sctp_addto_param(retval, num_ext, extensions);
+	}
+	if (asoc->peer.prsctp_capable)
+		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
+
+	if (sp->adaptation_ind) {
+		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
+		aiparam.param_hdr.length = htons(sizeof(aiparam));
+		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
+		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
+	}
+
+	if (asoc->peer.auth_capable) {
+		sctp_addto_chunk(retval, ntohs(auth_random->length),
+				 auth_random);
+		if (auth_hmacs)
+			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
+					auth_hmacs);
+		if (auth_chunks)
+			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
+					auth_chunks);
+	}
+
+	/* We need to remove the const qualifier at this point.  */
+	retval->asoc = (struct sctp_association *) asoc;
+
+nomem_chunk:
+	kfree(cookie);
+nomem_cookie:
+	kfree(addrs.v);
+	return retval;
+}
+
+/* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
+ *
+ * This chunk is used only during the initialization of an association.
+ * It is sent by the initiator of an association to its peer to complete
+ * the initialization process. This chunk MUST precede any DATA chunk
+ * sent within the association, but MAY be bundled with one or more DATA
+ * chunks in the same packet.
+ *
+ *      0                   1                   2                   3
+ *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |   Type = 10   |Chunk  Flags   |         Length                |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     /                     Cookie                                    /
+ *     \                                                               \
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Chunk Flags: 8 bit
+ *
+ *   Set to zero on transmit and ignored on receipt.
+ *
+ * Length: 16 bits (unsigned integer)
+ *
+ *   Set to the size of the chunk in bytes, including the 4 bytes of
+ *   the chunk header and the size of the Cookie.
+ *
+ * Cookie: variable size
+ *
+ *   This field must contain the exact cookie received in the
+ *   State Cookie parameter from the previous INIT ACK.
+ *
+ *   An implementation SHOULD make the cookie as small as possible
+ *   to insure interoperability.
+ */
+struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
+					 const struct sctp_chunk *chunk)
+{
+	struct sctp_chunk *retval;
+	int cookie_len;
+	void *cookie;
+
+	cookie = asoc->peer.cookie;
+	cookie_len = asoc->peer.cookie_len;
+
+	/* Build a cookie echo chunk.  */
+	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0,
+				   cookie_len, GFP_ATOMIC);
+	if (!retval)
+		goto nodata;
+	retval->subh.cookie_hdr =
+		sctp_addto_chunk(retval, cookie_len, cookie);
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, * etc.) to the same destination transport
+	 * address from which it * received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 * [COOKIE ECHO back to where the INIT ACK came from.]
+	 */
+	if (chunk)
+		retval->transport = chunk->transport;
+
+nodata:
+	return retval;
+}
+
+/* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
+ *
+ * This chunk is used only during the initialization of an
+ * association.  It is used to acknowledge the receipt of a COOKIE
+ * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
+ * within the association, but MAY be bundled with one or more DATA
+ * chunks or SACK chunk in the same SCTP packet.
+ *
+ *      0                   1                   2                   3
+ *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Chunk Flags: 8 bits
+ *
+ *   Set to zero on transmit and ignored on receipt.
+ */
+struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk)
+{
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ACK, 0, 0, GFP_ATOMIC);
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, * etc.) to the same destination transport
+	 * address from which it * received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 * [COOKIE ACK back to where the COOKIE ECHO came from.]
+	 */
+	if (retval && chunk && chunk->transport)
+		retval->transport =
+			sctp_assoc_lookup_paddr(asoc,
+						&chunk->transport->ipaddr);
+
+	return retval;
+}
+
+/*
+ *  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.
+ *
+ *     0                   1                   2                   3
+ *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                      Lowest TSN Number                        |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ *     Note: The CWR is considered a Control chunk.
+ */
+struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
+				 const __u32 lowest_tsn,
+				 const struct sctp_chunk *chunk)
+{
+	struct sctp_chunk *retval;
+	struct sctp_cwrhdr cwr;
+
+	cwr.lowest_tsn = htonl(lowest_tsn);
+	retval = sctp_make_control(asoc, SCTP_CID_ECN_CWR, 0,
+				   sizeof(cwr), GFP_ATOMIC);
+
+	if (!retval)
+		goto nodata;
+
+	retval->subh.ecn_cwr_hdr =
+		sctp_addto_chunk(retval, sizeof(cwr), &cwr);
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, * etc.) to the same destination transport
+	 * address from which it * received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 * [Report a reduced congestion window back to where the ECNE
+	 * came from.]
+	 */
+	if (chunk)
+		retval->transport = chunk->transport;
+
+nodata:
+	return retval;
+}
+
+/* Make an ECNE chunk.  This is a congestion experienced report.  */
+struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
+				  const __u32 lowest_tsn)
+{
+	struct sctp_chunk *retval;
+	struct sctp_ecnehdr ecne;
+
+	ecne.lowest_tsn = htonl(lowest_tsn);
+	retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0,
+				   sizeof(ecne), GFP_ATOMIC);
+	if (!retval)
+		goto nodata;
+	retval->subh.ecne_hdr =
+		sctp_addto_chunk(retval, sizeof(ecne), &ecne);
+
+nodata:
+	return retval;
+}
+
+/* Make a DATA chunk for the given association from the provided
+ * parameters.  However, do not populate the data payload.
+ */
+struct sctp_chunk *sctp_make_datafrag_empty(const struct sctp_association *asoc,
+					    const struct sctp_sndrcvinfo *sinfo,
+					    int len, __u8 flags, gfp_t gfp)
+{
+	struct sctp_chunk *retval;
+	struct sctp_datahdr dp;
+
+	/* We assign the TSN as LATE as possible, not here when
+	 * creating the chunk.
+	 */
+	memset(&dp, 0, sizeof(dp));
+	dp.ppid = sinfo->sinfo_ppid;
+	dp.stream = htons(sinfo->sinfo_stream);
+
+	/* Set the flags for an unordered send.  */
+	if (sinfo->sinfo_flags & SCTP_UNORDERED)
+		flags |= SCTP_DATA_UNORDERED;
+
+	retval = sctp_make_data(asoc, flags, sizeof(dp) + len, gfp);
+	if (!retval)
+		return NULL;
+
+	retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
+	memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
+
+	return retval;
+}
+
+/* Create a selective ackowledgement (SACK) for the given
+ * association.  This reports on which TSN's we've seen to date,
+ * including duplicates and gaps.
+ */
+struct sctp_chunk *sctp_make_sack(struct sctp_association *asoc)
+{
+	struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
+	struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
+	__u16 num_gabs, num_dup_tsns;
+	struct sctp_transport *trans;
+	struct sctp_chunk *retval;
+	struct sctp_sackhdr sack;
+	__u32 ctsn;
+	int len;
+
+	memset(gabs, 0, sizeof(gabs));
+	ctsn = sctp_tsnmap_get_ctsn(map);
+
+	pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
+
+	/* How much room is needed in the chunk? */
+	num_gabs = sctp_tsnmap_num_gabs(map, gabs);
+	num_dup_tsns = sctp_tsnmap_num_dups(map);
+
+	/* Initialize the SACK header.  */
+	sack.cum_tsn_ack	    = htonl(ctsn);
+	sack.a_rwnd 		    = htonl(asoc->a_rwnd);
+	sack.num_gap_ack_blocks     = htons(num_gabs);
+	sack.num_dup_tsns           = htons(num_dup_tsns);
+
+	len = sizeof(sack)
+		+ sizeof(struct sctp_gap_ack_block) * num_gabs
+		+ sizeof(__u32) * num_dup_tsns;
+
+	/* Create the chunk.  */
+	retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len, GFP_ATOMIC);
+	if (!retval)
+		goto nodata;
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, etc.) to the same destination transport
+	 * address from which it received the DATA or control chunk to
+	 * which it is replying.  This rule should also be followed if
+	 * the endpoint is bundling DATA chunks together with the
+	 * reply chunk.
+	 *
+	 * However, when acknowledging multiple DATA chunks received
+	 * in packets from different source addresses in a single
+	 * SACK, the SACK chunk may be transmitted to one of the
+	 * destination transport addresses from which the DATA or
+	 * control chunks being acknowledged were received.
+	 *
+	 * [BUG:  We do not implement the following paragraph.
+	 * Perhaps we should remember the last transport we used for a
+	 * SACK and avoid that (if possible) if we have seen any
+	 * duplicates. --piggy]
+	 *
+	 * When a receiver of a duplicate DATA chunk sends a SACK to a
+	 * multi- homed endpoint it MAY be beneficial to vary the
+	 * destination address and not use the source address of the
+	 * DATA chunk.  The reason being that receiving a duplicate
+	 * from a multi-homed endpoint might indicate that the return
+	 * path (as specified in the source address of the DATA chunk)
+	 * for the SACK is broken.
+	 *
+	 * [Send to the address from which we last received a DATA chunk.]
+	 */
+	retval->transport = asoc->peer.last_data_from;
+
+	retval->subh.sack_hdr =
+		sctp_addto_chunk(retval, sizeof(sack), &sack);
+
+	/* Add the gap ack block information.   */
+	if (num_gabs)
+		sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
+				 gabs);
+
+	/* Add the duplicate TSN information.  */
+	if (num_dup_tsns) {
+		asoc->stats.idupchunks += num_dup_tsns;
+		sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
+				 sctp_tsnmap_get_dups(map));
+	}
+	/* Once we have a sack generated, check to see what our sack
+	 * generation is, if its 0, reset the transports to 0, and reset
+	 * the association generation to 1
+	 *
+	 * The idea is that zero is never used as a valid generation for the
+	 * association so no transport will match after a wrap event like this,
+	 * Until the next sack
+	 */
+	if (++asoc->peer.sack_generation == 0) {
+		list_for_each_entry(trans, &asoc->peer.transport_addr_list,
+				    transports)
+			trans->sack_generation = 0;
+		asoc->peer.sack_generation = 1;
+	}
+nodata:
+	return retval;
+}
+
+/* Make a SHUTDOWN chunk. */
+struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
+				      const struct sctp_chunk *chunk)
+{
+	struct sctp_shutdownhdr shut;
+	struct sctp_chunk *retval;
+	__u32 ctsn;
+
+	if (chunk && chunk->asoc)
+		ctsn = sctp_tsnmap_get_ctsn(&chunk->asoc->peer.tsn_map);
+	else
+		ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
+
+	shut.cum_tsn_ack = htonl(ctsn);
+
+	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,
+				   sizeof(shut), GFP_ATOMIC);
+	if (!retval)
+		goto nodata;
+
+	retval->subh.shutdown_hdr =
+		sctp_addto_chunk(retval, sizeof(shut), &shut);
+
+	if (chunk)
+		retval->transport = chunk->transport;
+nodata:
+	return retval;
+}
+
+struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
+					  const struct sctp_chunk *chunk)
+{
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0,
+				   GFP_ATOMIC);
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, * etc.) to the same destination transport
+	 * address from which it * received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 * [ACK back to where the SHUTDOWN came from.]
+	 */
+	if (retval && chunk)
+		retval->transport = chunk->transport;
+
+	return retval;
+}
+
+struct sctp_chunk *sctp_make_shutdown_complete(
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk)
+{
+	struct sctp_chunk *retval;
+	__u8 flags = 0;
+
+	/* Set the T-bit if we have no association (vtag will be
+	 * reflected)
+	 */
+	flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
+
+	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags,
+				   0, GFP_ATOMIC);
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, * etc.) to the same destination transport
+	 * address from which it * received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
+	 * came from.]
+	 */
+	if (retval && chunk)
+		retval->transport = chunk->transport;
+
+	return retval;
+}
+
+/* Create an ABORT.  Note that we set the T bit if we have no
+ * association, except when responding to an INIT (sctpimpguide 2.41).
+ */
+struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
+				   const struct sctp_chunk *chunk,
+				   const size_t hint)
+{
+	struct sctp_chunk *retval;
+	__u8 flags = 0;
+
+	/* Set the T-bit if we have no association and 'chunk' is not
+	 * an INIT (vtag will be reflected).
+	 */
+	if (!asoc) {
+		if (chunk && chunk->chunk_hdr &&
+		    chunk->chunk_hdr->type == SCTP_CID_INIT)
+			flags = 0;
+		else
+			flags = SCTP_CHUNK_FLAG_T;
+	}
+
+	retval = sctp_make_control(asoc, SCTP_CID_ABORT, flags, hint,
+				   GFP_ATOMIC);
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, * etc.) to the same destination transport
+	 * address from which it * received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 * [ABORT back to where the offender came from.]
+	 */
+	if (retval && chunk)
+		retval->transport = chunk->transport;
+
+	return retval;
+}
+
+/* Helper to create ABORT with a NO_USER_DATA error.  */
+struct sctp_chunk *sctp_make_abort_no_data(
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk,
+					__u32 tsn)
+{
+	struct sctp_chunk *retval;
+	__be32 payload;
+
+	retval = sctp_make_abort(asoc, chunk,
+				 sizeof(struct sctp_errhdr) + sizeof(tsn));
+
+	if (!retval)
+		goto no_mem;
+
+	/* Put the tsn back into network byte order.  */
+	payload = htonl(tsn);
+	sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
+	sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, * etc.) to the same destination transport
+	 * address from which it * received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 * [ABORT back to where the offender came from.]
+	 */
+	if (chunk)
+		retval->transport = chunk->transport;
+
+no_mem:
+	return retval;
+}
+
+/* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
+struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
+					struct msghdr *msg,
+					size_t paylen)
+{
+	struct sctp_chunk *retval;
+	void *payload = NULL;
+	int err;
+
+	retval = sctp_make_abort(asoc, NULL,
+				 sizeof(struct sctp_errhdr) + paylen);
+	if (!retval)
+		goto err_chunk;
+
+	if (paylen) {
+		/* Put the msg_iov together into payload.  */
+		payload = kmalloc(paylen, GFP_KERNEL);
+		if (!payload)
+			goto err_payload;
+
+		err = memcpy_from_msg(payload, msg, paylen);
+		if (err < 0)
+			goto err_copy;
+	}
+
+	sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
+	sctp_addto_chunk(retval, paylen, payload);
+
+	if (paylen)
+		kfree(payload);
+
+	return retval;
+
+err_copy:
+	kfree(payload);
+err_payload:
+	sctp_chunk_free(retval);
+	retval = NULL;
+err_chunk:
+	return retval;
+}
+
+/* Append bytes to the end of a parameter.  Will panic if chunk is not big
+ * enough.
+ */
+static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
+			      const void *data)
+{
+	int chunklen = ntohs(chunk->chunk_hdr->length);
+	void *target;
+
+	target = skb_put(chunk->skb, len);
+
+	if (data)
+		memcpy(target, data, len);
+	else
+		memset(target, 0, len);
+
+	/* Adjust the chunk length field.  */
+	chunk->chunk_hdr->length = htons(chunklen + len);
+	chunk->chunk_end = skb_tail_pointer(chunk->skb);
+
+	return target;
+}
+
+/* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
+struct sctp_chunk *sctp_make_abort_violation(
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk,
+					const __u8 *payload,
+					const size_t paylen)
+{
+	struct sctp_chunk  *retval;
+	struct sctp_paramhdr phdr;
+
+	retval = sctp_make_abort(asoc, chunk, sizeof(struct sctp_errhdr) +
+					      paylen + sizeof(phdr));
+	if (!retval)
+		goto end;
+
+	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen +
+							    sizeof(phdr));
+
+	phdr.type = htons(chunk->chunk_hdr->type);
+	phdr.length = chunk->chunk_hdr->length;
+	sctp_addto_chunk(retval, paylen, payload);
+	sctp_addto_param(retval, sizeof(phdr), &phdr);
+
+end:
+	return retval;
+}
+
+struct sctp_chunk *sctp_make_violation_paramlen(
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk,
+					struct sctp_paramhdr *param)
+{
+	static const char error[] = "The following parameter had invalid length:";
+	size_t payload_len = sizeof(error) + sizeof(struct sctp_errhdr) +
+			     sizeof(*param);
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_abort(asoc, chunk, payload_len);
+	if (!retval)
+		goto nodata;
+
+	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
+			sizeof(error) + sizeof(*param));
+	sctp_addto_chunk(retval, sizeof(error), error);
+	sctp_addto_param(retval, sizeof(*param), param);
+
+nodata:
+	return retval;
+}
+
+struct sctp_chunk *sctp_make_violation_max_retrans(
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk)
+{
+	static const char error[] = "Association exceeded its max_retrans count";
+	size_t payload_len = sizeof(error) + sizeof(struct sctp_errhdr);
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_abort(asoc, chunk, payload_len);
+	if (!retval)
+		goto nodata;
+
+	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, sizeof(error));
+	sctp_addto_chunk(retval, sizeof(error), error);
+
+nodata:
+	return retval;
+}
+
+/* Make a HEARTBEAT chunk.  */
+struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
+				       const struct sctp_transport *transport)
+{
+	struct sctp_sender_hb_info hbinfo;
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT, 0,
+				   sizeof(hbinfo), GFP_ATOMIC);
+
+	if (!retval)
+		goto nodata;
+
+	hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
+	hbinfo.param_hdr.length = htons(sizeof(hbinfo));
+	hbinfo.daddr = transport->ipaddr;
+	hbinfo.sent_at = jiffies;
+	hbinfo.hb_nonce = transport->hb_nonce;
+
+	/* Cast away the 'const', as this is just telling the chunk
+	 * what transport it belongs to.
+	 */
+	retval->transport = (struct sctp_transport *) transport;
+	retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
+						&hbinfo);
+
+nodata:
+	return retval;
+}
+
+struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
+					   const struct sctp_chunk *chunk,
+					   const void *payload,
+					   const size_t paylen)
+{
+	struct sctp_chunk *retval;
+
+	retval  = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen,
+				    GFP_ATOMIC);
+	if (!retval)
+		goto nodata;
+
+	retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, * etc.) to the same destination transport
+	 * address from which it * received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 * [HBACK back to where the HEARTBEAT came from.]
+	 */
+	if (chunk)
+		retval->transport = chunk->transport;
+
+nodata:
+	return retval;
+}
+
+/* Create an Operation Error chunk with the specified space reserved.
+ * This routine can be used for containing multiple causes in the chunk.
+ */
+static struct sctp_chunk *sctp_make_op_error_space(
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk,
+					size_t size)
+{
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_control(asoc, SCTP_CID_ERROR, 0,
+				   sizeof(struct sctp_errhdr) + size,
+				   GFP_ATOMIC);
+	if (!retval)
+		goto nodata;
+
+	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
+	 *
+	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
+	 * HEARTBEAT ACK, etc.) to the same destination transport
+	 * address from which it received the DATA or control chunk
+	 * to which it is replying.
+	 *
+	 */
+	if (chunk)
+		retval->transport = chunk->transport;
+
+nodata:
+	return retval;
+}
+
+/* Create an Operation Error chunk of a fixed size, specifically,
+ * min(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT) - overheads.
+ * This is a helper function to allocate an error chunk for those
+ * invalid parameter codes in which we may not want to report all the
+ * errors, if the incoming chunk is large. If it can't fit in a single
+ * packet, we ignore it.
+ */
+static inline struct sctp_chunk *sctp_make_op_error_limited(
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk)
+{
+	size_t size = SCTP_DEFAULT_MAXSEGMENT;
+	struct sctp_sock *sp = NULL;
+
+	if (asoc) {
+		size = min_t(size_t, size, asoc->pathmtu);
+		sp = sctp_sk(asoc->base.sk);
+	}
+
+	size = sctp_mtu_payload(sp, size, sizeof(struct sctp_errhdr));
+
+	return sctp_make_op_error_space(asoc, chunk, size);
+}
+
+/* Create an Operation Error chunk.  */
+struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
+				      const struct sctp_chunk *chunk,
+				      __be16 cause_code, const void *payload,
+				      size_t paylen, size_t reserve_tail)
+{
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
+	if (!retval)
+		goto nodata;
+
+	sctp_init_cause(retval, cause_code, paylen + reserve_tail);
+	sctp_addto_chunk(retval, paylen, payload);
+	if (reserve_tail)
+		sctp_addto_param(retval, reserve_tail, NULL);
+
+nodata:
+	return retval;
+}
+
+struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc,
+				  __u16 key_id)
+{
+	struct sctp_authhdr auth_hdr;
+	struct sctp_hmac *hmac_desc;
+	struct sctp_chunk *retval;
+
+	/* Get the first hmac that the peer told us to use */
+	hmac_desc = sctp_auth_asoc_get_hmac(asoc);
+	if (unlikely(!hmac_desc))
+		return NULL;
+
+	retval = sctp_make_control(asoc, SCTP_CID_AUTH, 0,
+				   hmac_desc->hmac_len + sizeof(auth_hdr),
+				   GFP_ATOMIC);
+	if (!retval)
+		return NULL;
+
+	auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
+	auth_hdr.shkey_id = htons(key_id);
+
+	retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(auth_hdr),
+						 &auth_hdr);
+
+	skb_put_zero(retval->skb, hmac_desc->hmac_len);
+
+	/* Adjust the chunk header to include the empty MAC */
+	retval->chunk_hdr->length =
+		htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
+	retval->chunk_end = skb_tail_pointer(retval->skb);
+
+	return retval;
+}
+
+
+/********************************************************************
+ * 2nd Level Abstractions
+ ********************************************************************/
+
+/* Turn an skb into a chunk.
+ * FIXME: Eventually move the structure directly inside the skb->cb[].
+ *
+ * sctpimpguide-05.txt Section 2.8.2
+ * M1) Each time a new DATA chunk is transmitted
+ * set the 'TSN.Missing.Report' count for that TSN to 0. The
+ * 'TSN.Missing.Report' count will be used to determine missing chunks
+ * and when to fast retransmit.
+ *
+ */
+struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
+				 const struct sctp_association *asoc,
+				 struct sock *sk, gfp_t gfp)
+{
+	struct sctp_chunk *retval;
+
+	retval = kmem_cache_zalloc(sctp_chunk_cachep, gfp);
+
+	if (!retval)
+		goto nodata;
+	if (!sk)
+		pr_debug("%s: chunkifying skb:%p w/o an sk\n", __func__, skb);
+
+	INIT_LIST_HEAD(&retval->list);
+	retval->skb		= skb;
+	retval->asoc		= (struct sctp_association *)asoc;
+	retval->singleton	= 1;
+
+	retval->fast_retransmit = SCTP_CAN_FRTX;
+
+	/* Polish the bead hole.  */
+	INIT_LIST_HEAD(&retval->transmitted_list);
+	INIT_LIST_HEAD(&retval->frag_list);
+	SCTP_DBG_OBJCNT_INC(chunk);
+	refcount_set(&retval->refcnt, 1);
+
+nodata:
+	return retval;
+}
+
+/* Set chunk->source and dest based on the IP header in chunk->skb.  */
+void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
+		     union sctp_addr *dest)
+{
+	memcpy(&chunk->source, src, sizeof(union sctp_addr));
+	memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
+}
+
+/* Extract the source address from a chunk.  */
+const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
+{
+	/* If we have a known transport, use that.  */
+	if (chunk->transport) {
+		return &chunk->transport->ipaddr;
+	} else {
+		/* Otherwise, extract it from the IP header.  */
+		return &chunk->source;
+	}
+}
+
+/* Create a new chunk, setting the type and flags headers from the
+ * arguments, reserving enough space for a 'paylen' byte payload.
+ */
+static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
+					   __u8 type, __u8 flags, int paylen,
+					   gfp_t gfp)
+{
+	struct sctp_chunkhdr *chunk_hdr;
+	struct sctp_chunk *retval;
+	struct sk_buff *skb;
+	struct sock *sk;
+	int chunklen;
+
+	chunklen = SCTP_PAD4(sizeof(*chunk_hdr) + paylen);
+	if (chunklen > SCTP_MAX_CHUNK_LEN)
+		goto nodata;
+
+	/* No need to allocate LL here, as this is only a chunk. */
+	skb = alloc_skb(chunklen, gfp);
+	if (!skb)
+		goto nodata;
+
+	/* Make room for the chunk header.  */
+	chunk_hdr = (struct sctp_chunkhdr *)skb_put(skb, sizeof(*chunk_hdr));
+	chunk_hdr->type	  = type;
+	chunk_hdr->flags  = flags;
+	chunk_hdr->length = htons(sizeof(*chunk_hdr));
+
+	sk = asoc ? asoc->base.sk : NULL;
+	retval = sctp_chunkify(skb, asoc, sk, gfp);
+	if (!retval) {
+		kfree_skb(skb);
+		goto nodata;
+	}
+
+	retval->chunk_hdr = chunk_hdr;
+	retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(*chunk_hdr);
+
+	/* Determine if the chunk needs to be authenticated */
+	if (sctp_auth_send_cid(type, asoc))
+		retval->auth = 1;
+
+	return retval;
+nodata:
+	return NULL;
+}
+
+static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
+					 __u8 flags, int paylen, gfp_t gfp)
+{
+	return _sctp_make_chunk(asoc, SCTP_CID_DATA, flags, paylen, gfp);
+}
+
+struct sctp_chunk *sctp_make_idata(const struct sctp_association *asoc,
+				   __u8 flags, int paylen, gfp_t gfp)
+{
+	return _sctp_make_chunk(asoc, SCTP_CID_I_DATA, flags, paylen, gfp);
+}
+
+static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
+					    __u8 type, __u8 flags, int paylen,
+					    gfp_t gfp)
+{
+	struct sctp_chunk *chunk;
+
+	chunk = _sctp_make_chunk(asoc, type, flags, paylen, gfp);
+	if (chunk)
+		sctp_control_set_owner_w(chunk);
+
+	return chunk;
+}
+
+/* Release the memory occupied by a chunk.  */
+static void sctp_chunk_destroy(struct sctp_chunk *chunk)
+{
+	BUG_ON(!list_empty(&chunk->list));
+	list_del_init(&chunk->transmitted_list);
+
+	consume_skb(chunk->skb);
+	consume_skb(chunk->auth_chunk);
+
+	SCTP_DBG_OBJCNT_DEC(chunk);
+	kmem_cache_free(sctp_chunk_cachep, chunk);
+}
+
+/* Possibly, free the chunk.  */
+void sctp_chunk_free(struct sctp_chunk *chunk)
+{
+	/* Release our reference on the message tracker. */
+	if (chunk->msg)
+		sctp_datamsg_put(chunk->msg);
+
+	sctp_chunk_put(chunk);
+}
+
+/* Grab a reference to the chunk. */
+void sctp_chunk_hold(struct sctp_chunk *ch)
+{
+	refcount_inc(&ch->refcnt);
+}
+
+/* Release a reference to the chunk. */
+void sctp_chunk_put(struct sctp_chunk *ch)
+{
+	if (refcount_dec_and_test(&ch->refcnt))
+		sctp_chunk_destroy(ch);
+}
+
+/* Append bytes to the end of a chunk.  Will panic if chunk is not big
+ * enough.
+ */
+void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
+{
+	int chunklen = ntohs(chunk->chunk_hdr->length);
+	int padlen = SCTP_PAD4(chunklen) - chunklen;
+	void *target;
+
+	skb_put_zero(chunk->skb, padlen);
+	target = skb_put_data(chunk->skb, data, len);
+
+	/* Adjust the chunk length field.  */
+	chunk->chunk_hdr->length = htons(chunklen + padlen + len);
+	chunk->chunk_end = skb_tail_pointer(chunk->skb);
+
+	return target;
+}
+
+/* Append bytes from user space to the end of a chunk.  Will panic if
+ * chunk is not big enough.
+ * Returns a kernel err value.
+ */
+int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
+			  struct iov_iter *from)
+{
+	void *target;
+
+	/* Make room in chunk for data.  */
+	target = skb_put(chunk->skb, len);
+
+	/* Copy data (whole iovec) into chunk */
+	if (!copy_from_iter_full(target, len, from))
+		return -EFAULT;
+
+	/* Adjust the chunk length field.  */
+	chunk->chunk_hdr->length =
+		htons(ntohs(chunk->chunk_hdr->length) + len);
+	chunk->chunk_end = skb_tail_pointer(chunk->skb);
+
+	return 0;
+}
+
+/* Helper function to assign a TSN if needed.  This assumes that both
+ * the data_hdr and association have already been assigned.
+ */
+void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
+{
+	struct sctp_stream *stream;
+	struct sctp_chunk *lchunk;
+	struct sctp_datamsg *msg;
+	__u16 ssn, sid;
+
+	if (chunk->has_ssn)
+		return;
+
+	/* All fragments will be on the same stream */
+	sid = ntohs(chunk->subh.data_hdr->stream);
+	stream = &chunk->asoc->stream;
+
+	/* Now assign the sequence number to the entire message.
+	 * All fragments must have the same stream sequence number.
+	 */
+	msg = chunk->msg;
+	list_for_each_entry(lchunk, &msg->chunks, frag_list) {
+		if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
+			ssn = 0;
+		} else {
+			if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
+				ssn = sctp_ssn_next(stream, out, sid);
+			else
+				ssn = sctp_ssn_peek(stream, out, sid);
+		}
+
+		lchunk->subh.data_hdr->ssn = htons(ssn);
+		lchunk->has_ssn = 1;
+	}
+}
+
+/* Helper function to assign a TSN if needed.  This assumes that both
+ * the data_hdr and association have already been assigned.
+ */
+void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
+{
+	if (!chunk->has_tsn) {
+		/* This is the last possible instant to
+		 * assign a TSN.
+		 */
+		chunk->subh.data_hdr->tsn =
+			htonl(sctp_association_get_next_tsn(chunk->asoc));
+		chunk->has_tsn = 1;
+	}
+}
+
+/* Create a CLOSED association to use with an incoming packet.  */
+struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
+					     struct sctp_chunk *chunk,
+					     gfp_t gfp)
+{
+	struct sctp_association *asoc;
+	enum sctp_scope scope;
+	struct sk_buff *skb;
+
+	/* Create the bare association.  */
+	scope = sctp_scope(sctp_source(chunk));
+	asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
+	if (!asoc)
+		goto nodata;
+	asoc->temp = 1;
+	skb = chunk->skb;
+	/* Create an entry for the source address of the packet.  */
+	SCTP_INPUT_CB(skb)->af->from_skb(&asoc->c.peer_addr, skb, 1);
+
+nodata:
+	return asoc;
+}
+
+/* Build a cookie representing asoc.
+ * This INCLUDES the param header needed to put the cookie in the INIT ACK.
+ */
+static struct sctp_cookie_param *sctp_pack_cookie(
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *init_chunk,
+					int *cookie_len, const __u8 *raw_addrs,
+					int addrs_len)
+{
+	struct sctp_signed_cookie *cookie;
+	struct sctp_cookie_param *retval;
+	int headersize, bodysize;
+
+	/* Header size is static data prior to the actual cookie, including
+	 * any padding.
+	 */
+	headersize = sizeof(struct sctp_paramhdr) +
+		     (sizeof(struct sctp_signed_cookie) -
+		      sizeof(struct sctp_cookie));
+	bodysize = sizeof(struct sctp_cookie)
+		+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;
+
+	/* Pad out the cookie to a multiple to make the signature
+	 * functions simpler to write.
+	 */
+	if (bodysize % SCTP_COOKIE_MULTIPLE)
+		bodysize += SCTP_COOKIE_MULTIPLE
+			- (bodysize % SCTP_COOKIE_MULTIPLE);
+	*cookie_len = headersize + bodysize;
+
+	/* Clear this memory since we are sending this data structure
+	 * out on the network.
+	 */
+	retval = kzalloc(*cookie_len, GFP_ATOMIC);
+	if (!retval)
+		goto nodata;
+
+	cookie = (struct sctp_signed_cookie *) retval->body;
+
+	/* Set up the parameter header.  */
+	retval->p.type = SCTP_PARAM_STATE_COOKIE;
+	retval->p.length = htons(*cookie_len);
+
+	/* Copy the cookie part of the association itself.  */
+	cookie->c = asoc->c;
+	/* Save the raw address list length in the cookie. */
+	cookie->c.raw_addr_list_len = addrs_len;
+
+	/* Remember PR-SCTP capability. */
+	cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
+
+	/* Save adaptation indication in the cookie. */
+	cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
+
+	/* Set an expiration time for the cookie.  */
+	cookie->c.expiration = ktime_add(asoc->cookie_life,
+					 ktime_get_real());
+
+	/* Copy the peer's init packet.  */
+	memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
+	       ntohs(init_chunk->chunk_hdr->length));
+
+	/* Copy the raw local address list of the association. */
+	memcpy((__u8 *)&cookie->c.peer_init[0] +
+	       ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
+
+	if (sctp_sk(ep->base.sk)->hmac) {
+		struct crypto_shash *tfm = sctp_sk(ep->base.sk)->hmac;
+		int err;
+
+		/* Sign the message.  */
+		err = crypto_shash_setkey(tfm, ep->secret_key,
+					  sizeof(ep->secret_key)) ?:
+		      crypto_shash_tfm_digest(tfm, (u8 *)&cookie->c, bodysize,
+					      cookie->signature);
+		if (err)
+			goto free_cookie;
+	}
+
+	return retval;
+
+free_cookie:
+	kfree(retval);
+nodata:
+	*cookie_len = 0;
+	return NULL;
+}
+
+/* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
+struct sctp_association *sctp_unpack_cookie(
+					const struct sctp_endpoint *ep,
+					const struct sctp_association *asoc,
+					struct sctp_chunk *chunk, gfp_t gfp,
+					int *error, struct sctp_chunk **errp)
+{
+	struct sctp_association *retval = NULL;
+	int headersize, bodysize, fixed_size;
+	struct sctp_signed_cookie *cookie;
+	struct sk_buff *skb = chunk->skb;
+	struct sctp_cookie *bear_cookie;
+	__u8 *digest = ep->digest;
+	enum sctp_scope scope;
+	unsigned int len;
+	ktime_t kt;
+
+	/* Header size is static data prior to the actual cookie, including
+	 * any padding.
+	 */
+	headersize = sizeof(struct sctp_chunkhdr) +
+		     (sizeof(struct sctp_signed_cookie) -
+		      sizeof(struct sctp_cookie));
+	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
+	fixed_size = headersize + sizeof(struct sctp_cookie);
+
+	/* Verify that the chunk looks like it even has a cookie.
+	 * There must be enough room for our cookie and our peer's
+	 * INIT chunk.
+	 */
+	len = ntohs(chunk->chunk_hdr->length);
+	if (len < fixed_size + sizeof(struct sctp_chunkhdr))
+		goto malformed;
+
+	/* Verify that the cookie has been padded out. */
+	if (bodysize % SCTP_COOKIE_MULTIPLE)
+		goto malformed;
+
+	/* Process the cookie.  */
+	cookie = chunk->subh.cookie_hdr;
+	bear_cookie = &cookie->c;
+
+	if (!sctp_sk(ep->base.sk)->hmac)
+		goto no_hmac;
+
+	/* Check the signature.  */
+	{
+		struct crypto_shash *tfm = sctp_sk(ep->base.sk)->hmac;
+		int err;
+
+		err = crypto_shash_setkey(tfm, ep->secret_key,
+					  sizeof(ep->secret_key)) ?:
+		      crypto_shash_tfm_digest(tfm, (u8 *)bear_cookie, bodysize,
+					      digest);
+		if (err) {
+			*error = -SCTP_IERROR_NOMEM;
+			goto fail;
+		}
+	}
+
+	if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
+		*error = -SCTP_IERROR_BAD_SIG;
+		goto fail;
+	}
+
+no_hmac:
+	/* IG Section 2.35.2:
+	 *  3) Compare the port numbers and the verification tag contained
+	 *     within the COOKIE ECHO chunk to the actual port numbers and the
+	 *     verification tag within the SCTP common header of the received
+	 *     packet. If these values do not match the packet MUST be silently
+	 *     discarded,
+	 */
+	if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
+		*error = -SCTP_IERROR_BAD_TAG;
+		goto fail;
+	}
+
+	if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
+	    ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
+		*error = -SCTP_IERROR_BAD_PORTS;
+		goto fail;
+	}
+
+	/* Check to see if the cookie is stale.  If there is already
+	 * an association, there is no need to check cookie's expiration
+	 * for init collision case of lost COOKIE ACK.
+	 * If skb has been timestamped, then use the stamp, otherwise
+	 * use current time.  This introduces a small possibility that
+	 * a cookie may be considered expired, but this would only slow
+	 * down the new association establishment instead of every packet.
+	 */
+	if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
+		kt = skb_get_ktime(skb);
+	else
+		kt = ktime_get_real();
+
+	if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
+		suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
+		__be32 n = htonl(usecs);
+
+		/*
+		 * Section 3.3.10.3 Stale Cookie Error (3)
+		 *
+		 * Cause of error
+		 * ---------------
+		 * Stale Cookie Error:  Indicates the receipt of a valid State
+		 * Cookie that has expired.
+		 */
+		*errp = sctp_make_op_error(asoc, chunk,
+					   SCTP_ERROR_STALE_COOKIE, &n,
+					   sizeof(n), 0);
+		if (*errp)
+			*error = -SCTP_IERROR_STALE_COOKIE;
+		else
+			*error = -SCTP_IERROR_NOMEM;
+
+		goto fail;
+	}
+
+	/* Make a new base association.  */
+	scope = sctp_scope(sctp_source(chunk));
+	retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
+	if (!retval) {
+		*error = -SCTP_IERROR_NOMEM;
+		goto fail;
+	}
+
+	/* Set up our peer's port number.  */
+	retval->peer.port = ntohs(chunk->sctp_hdr->source);
+
+	/* Populate the association from the cookie.  */
+	memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
+
+	if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
+						 GFP_ATOMIC) < 0) {
+		*error = -SCTP_IERROR_NOMEM;
+		goto fail;
+	}
+
+	/* Also, add the destination address. */
+	if (list_empty(&retval->base.bind_addr.address_list)) {
+		sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
+				   sizeof(chunk->dest), SCTP_ADDR_SRC,
+				   GFP_ATOMIC);
+	}
+
+	retval->next_tsn = retval->c.initial_tsn;
+	retval->ctsn_ack_point = retval->next_tsn - 1;
+	retval->addip_serial = retval->c.initial_tsn;
+	retval->strreset_outseq = retval->c.initial_tsn;
+	retval->adv_peer_ack_point = retval->ctsn_ack_point;
+	retval->peer.prsctp_capable = retval->c.prsctp_capable;
+	retval->peer.adaptation_ind = retval->c.adaptation_ind;
+
+	/* The INIT stuff will be done by the side effects.  */
+	return retval;
+
+fail:
+	if (retval)
+		sctp_association_free(retval);
+
+	return NULL;
+
+malformed:
+	/* Yikes!  The packet is either corrupt or deliberately
+	 * malformed.
+	 */
+	*error = -SCTP_IERROR_MALFORMED;
+	goto fail;
+}
+
+/********************************************************************
+ * 3rd Level Abstractions
+ ********************************************************************/
+
+struct __sctp_missing {
+	__be32 num_missing;
+	__be16 type;
+}  __packed;
+
+/*
+ * Report a missing mandatory parameter.
+ */
+static int sctp_process_missing_param(const struct sctp_association *asoc,
+				      enum sctp_param paramtype,
+				      struct sctp_chunk *chunk,
+				      struct sctp_chunk **errp)
+{
+	struct __sctp_missing report;
+	__u16 len;
+
+	len = SCTP_PAD4(sizeof(report));
+
+	/* Make an ERROR chunk, preparing enough room for
+	 * returning multiple unknown parameters.
+	 */
+	if (!*errp)
+		*errp = sctp_make_op_error_space(asoc, chunk, len);
+
+	if (*errp) {
+		report.num_missing = htonl(1);
+		report.type = paramtype;
+		sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
+				sizeof(report));
+		sctp_addto_chunk(*errp, sizeof(report), &report);
+	}
+
+	/* Stop processing this chunk. */
+	return 0;
+}
+
+/* Report an Invalid Mandatory Parameter.  */
+static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
+				      struct sctp_chunk *chunk,
+				      struct sctp_chunk **errp)
+{
+	/* Invalid Mandatory Parameter Error has no payload. */
+
+	if (!*errp)
+		*errp = sctp_make_op_error_space(asoc, chunk, 0);
+
+	if (*errp)
+		sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
+
+	/* Stop processing this chunk. */
+	return 0;
+}
+
+static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
+					struct sctp_paramhdr *param,
+					const struct sctp_chunk *chunk,
+					struct sctp_chunk **errp)
+{
+	/* This is a fatal error.  Any accumulated non-fatal errors are
+	 * not reported.
+	 */
+	if (*errp)
+		sctp_chunk_free(*errp);
+
+	/* Create an error chunk and fill it in with our payload. */
+	*errp = sctp_make_violation_paramlen(asoc, chunk, param);
+
+	return 0;
+}
+
+
+/* Do not attempt to handle the HOST_NAME parm.  However, do
+ * send back an indicator to the peer.
+ */
+static int sctp_process_hn_param(const struct sctp_association *asoc,
+				 union sctp_params param,
+				 struct sctp_chunk *chunk,
+				 struct sctp_chunk **errp)
+{
+	__u16 len = ntohs(param.p->length);
+
+	/* Processing of the HOST_NAME parameter will generate an
+	 * ABORT.  If we've accumulated any non-fatal errors, they
+	 * would be unrecognized parameters and we should not include
+	 * them in the ABORT.
+	 */
+	if (*errp)
+		sctp_chunk_free(*errp);
+
+	*errp = sctp_make_op_error(asoc, chunk, SCTP_ERROR_DNS_FAILED,
+				   param.v, len, 0);
+
+	/* Stop processing this chunk. */
+	return 0;
+}
+
+static int sctp_verify_ext_param(struct net *net,
+				 const struct sctp_endpoint *ep,
+				 union sctp_params param)
+{
+	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
+	int have_asconf = 0;
+	int have_auth = 0;
+	int i;
+
+	for (i = 0; i < num_ext; i++) {
+		switch (param.ext->chunks[i]) {
+		case SCTP_CID_AUTH:
+			have_auth = 1;
+			break;
+		case SCTP_CID_ASCONF:
+		case SCTP_CID_ASCONF_ACK:
+			have_asconf = 1;
+			break;
+		}
+	}
+
+	/* ADD-IP Security: The draft requires us to ABORT or ignore the
+	 * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
+	 * only if ADD-IP is turned on and we are not backward-compatible
+	 * mode.
+	 */
+	if (net->sctp.addip_noauth)
+		return 1;
+
+	if (ep->asconf_enable && !have_auth && have_asconf)
+		return 0;
+
+	return 1;
+}
+
+static void sctp_process_ext_param(struct sctp_association *asoc,
+				   union sctp_params param)
+{
+	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
+	int i;
+
+	for (i = 0; i < num_ext; i++) {
+		switch (param.ext->chunks[i]) {
+		case SCTP_CID_RECONF:
+			if (asoc->ep->reconf_enable)
+				asoc->peer.reconf_capable = 1;
+			break;
+		case SCTP_CID_FWD_TSN:
+			if (asoc->ep->prsctp_enable)
+				asoc->peer.prsctp_capable = 1;
+			break;
+		case SCTP_CID_AUTH:
+			/* if the peer reports AUTH, assume that he
+			 * supports AUTH.
+			 */
+			if (asoc->ep->auth_enable)
+				asoc->peer.auth_capable = 1;
+			break;
+		case SCTP_CID_ASCONF:
+		case SCTP_CID_ASCONF_ACK:
+			if (asoc->ep->asconf_enable)
+				asoc->peer.asconf_capable = 1;
+			break;
+		case SCTP_CID_I_DATA:
+			if (asoc->ep->intl_enable)
+				asoc->peer.intl_capable = 1;
+			break;
+		default:
+			break;
+		}
+	}
+}
+
+/* RFC 3.2.1 & the Implementers Guide 2.2.
+ *
+ * The Parameter Types are encoded such that the
+ * highest-order two bits specify the action that must be
+ * taken if the processing endpoint does not recognize the
+ * Parameter Type.
+ *
+ * 00 - Stop processing this parameter; do not process any further
+ * 	parameters within this chunk
+ *
+ * 01 - Stop processing this parameter, do not process any further
+ *	parameters within this chunk, and report the unrecognized
+ *	parameter in an 'Unrecognized Parameter' ERROR chunk.
+ *
+ * 10 - Skip this parameter and continue processing.
+ *
+ * 11 - Skip this parameter and continue processing but
+ *	report the unrecognized parameter in an
+ *	'Unrecognized Parameter' ERROR chunk.
+ *
+ * Return value:
+ * 	SCTP_IERROR_NO_ERROR - continue with the chunk
+ * 	SCTP_IERROR_ERROR    - stop and report an error.
+ * 	SCTP_IERROR_NOMEME   - out of memory.
+ */
+static enum sctp_ierror sctp_process_unk_param(
+					const struct sctp_association *asoc,
+					union sctp_params param,
+					struct sctp_chunk *chunk,
+					struct sctp_chunk **errp)
+{
+	int retval = SCTP_IERROR_NO_ERROR;
+
+	switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
+	case SCTP_PARAM_ACTION_DISCARD:
+		retval =  SCTP_IERROR_ERROR;
+		break;
+	case SCTP_PARAM_ACTION_SKIP:
+		break;
+	case SCTP_PARAM_ACTION_DISCARD_ERR:
+		retval =  SCTP_IERROR_ERROR;
+		fallthrough;
+	case SCTP_PARAM_ACTION_SKIP_ERR:
+		/* Make an ERROR chunk, preparing enough room for
+		 * returning multiple unknown parameters.
+		 */
+		if (!*errp) {
+			*errp = sctp_make_op_error_limited(asoc, chunk);
+			if (!*errp) {
+				/* If there is no memory for generating the
+				 * ERROR report as specified, an ABORT will be
+				 * triggered to the peer and the association
+				 * won't be established.
+				 */
+				retval = SCTP_IERROR_NOMEM;
+				break;
+			}
+		}
+
+		if (!sctp_init_cause(*errp, SCTP_ERROR_UNKNOWN_PARAM,
+				     ntohs(param.p->length)))
+			sctp_addto_chunk(*errp, ntohs(param.p->length),
+					 param.v);
+		break;
+	default:
+		break;
+	}
+
+	return retval;
+}
+
+/* Verify variable length parameters
+ * Return values:
+ * 	SCTP_IERROR_ABORT - trigger an ABORT
+ * 	SCTP_IERROR_NOMEM - out of memory (abort)
+ *	SCTP_IERROR_ERROR - stop processing, trigger an ERROR
+ * 	SCTP_IERROR_NO_ERROR - continue with the chunk
+ */
+static enum sctp_ierror sctp_verify_param(struct net *net,
+					  const struct sctp_endpoint *ep,
+					  const struct sctp_association *asoc,
+					  union sctp_params param,
+					  enum sctp_cid cid,
+					  struct sctp_chunk *chunk,
+					  struct sctp_chunk **err_chunk)
+{
+	struct sctp_hmac_algo_param *hmacs;
+	int retval = SCTP_IERROR_NO_ERROR;
+	__u16 n_elt, id = 0;
+	int i;
+
+	/* FIXME - This routine is not looking at each parameter per the
+	 * chunk type, i.e., unrecognized parameters should be further
+	 * identified based on the chunk id.
+	 */
+
+	switch (param.p->type) {
+	case SCTP_PARAM_IPV4_ADDRESS:
+	case SCTP_PARAM_IPV6_ADDRESS:
+	case SCTP_PARAM_COOKIE_PRESERVATIVE:
+	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
+	case SCTP_PARAM_STATE_COOKIE:
+	case SCTP_PARAM_HEARTBEAT_INFO:
+	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
+	case SCTP_PARAM_ECN_CAPABLE:
+	case SCTP_PARAM_ADAPTATION_LAYER_IND:
+		break;
+
+	case SCTP_PARAM_SUPPORTED_EXT:
+		if (!sctp_verify_ext_param(net, ep, param))
+			return SCTP_IERROR_ABORT;
+		break;
+
+	case SCTP_PARAM_SET_PRIMARY:
+		if (!ep->asconf_enable)
+			goto unhandled;
+
+		if (ntohs(param.p->length) < sizeof(struct sctp_addip_param) +
+					     sizeof(struct sctp_paramhdr)) {
+			sctp_process_inv_paramlength(asoc, param.p,
+						     chunk, err_chunk);
+			retval = SCTP_IERROR_ABORT;
+		}
+		break;
+
+	case SCTP_PARAM_HOST_NAME_ADDRESS:
+		/* Tell the peer, we won't support this param.  */
+		sctp_process_hn_param(asoc, param, chunk, err_chunk);
+		retval = SCTP_IERROR_ABORT;
+		break;
+
+	case SCTP_PARAM_FWD_TSN_SUPPORT:
+		if (ep->prsctp_enable)
+			break;
+		goto unhandled;
+
+	case SCTP_PARAM_RANDOM:
+		if (!ep->auth_enable)
+			goto unhandled;
+
+		/* SCTP-AUTH: Secion 6.1
+		 * If the random number is not 32 byte long the association
+		 * MUST be aborted.  The ABORT chunk SHOULD contain the error
+		 * cause 'Protocol Violation'.
+		 */
+		if (SCTP_AUTH_RANDOM_LENGTH != ntohs(param.p->length) -
+					       sizeof(struct sctp_paramhdr)) {
+			sctp_process_inv_paramlength(asoc, param.p,
+						     chunk, err_chunk);
+			retval = SCTP_IERROR_ABORT;
+		}
+		break;
+
+	case SCTP_PARAM_CHUNKS:
+		if (!ep->auth_enable)
+			goto unhandled;
+
+		/* SCTP-AUTH: Section 3.2
+		 * The CHUNKS parameter MUST be included once in the INIT or
+		 *  INIT-ACK chunk if the sender wants to receive authenticated
+		 *  chunks.  Its maximum length is 260 bytes.
+		 */
+		if (260 < ntohs(param.p->length)) {
+			sctp_process_inv_paramlength(asoc, param.p,
+						     chunk, err_chunk);
+			retval = SCTP_IERROR_ABORT;
+		}
+		break;
+
+	case SCTP_PARAM_HMAC_ALGO:
+		if (!ep->auth_enable)
+			goto unhandled;
+
+		hmacs = (struct sctp_hmac_algo_param *)param.p;
+		n_elt = (ntohs(param.p->length) -
+			 sizeof(struct sctp_paramhdr)) >> 1;
+
+		/* SCTP-AUTH: Section 6.1
+		 * The HMAC algorithm based on SHA-1 MUST be supported and
+		 * included in the HMAC-ALGO parameter.
+		 */
+		for (i = 0; i < n_elt; i++) {
+			id = ntohs(hmacs->hmac_ids[i]);
+
+			if (id == SCTP_AUTH_HMAC_ID_SHA1)
+				break;
+		}
+
+		if (id != SCTP_AUTH_HMAC_ID_SHA1) {
+			sctp_process_inv_paramlength(asoc, param.p, chunk,
+						     err_chunk);
+			retval = SCTP_IERROR_ABORT;
+		}
+		break;
+unhandled:
+	default:
+		pr_debug("%s: unrecognized param:%d for chunk:%d\n",
+			 __func__, ntohs(param.p->type), cid);
+
+		retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
+		break;
+	}
+	return retval;
+}
+
+/* Verify the INIT packet before we process it.  */
+int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
+		     const struct sctp_association *asoc, enum sctp_cid cid,
+		     struct sctp_init_chunk *peer_init,
+		     struct sctp_chunk *chunk, struct sctp_chunk **errp)
+{
+	union sctp_params param;
+	bool has_cookie = false;
+	int result;
+
+	/* Check for missing mandatory parameters. Note: Initial TSN is
+	 * also mandatory, but is not checked here since the valid range
+	 * is 0..2**32-1. RFC4960, section 3.3.3.
+	 */
+	if (peer_init->init_hdr.num_outbound_streams == 0 ||
+	    peer_init->init_hdr.num_inbound_streams == 0 ||
+	    peer_init->init_hdr.init_tag == 0 ||
+	    ntohl(peer_init->init_hdr.a_rwnd) < SCTP_DEFAULT_MINWINDOW)
+		return sctp_process_inv_mandatory(asoc, chunk, errp);
+
+	sctp_walk_params(param, peer_init, init_hdr.params) {
+		if (param.p->type == SCTP_PARAM_STATE_COOKIE)
+			has_cookie = true;
+	}
+
+	/* There is a possibility that a parameter length was bad and
+	 * in that case we would have stoped walking the parameters.
+	 * The current param.p would point at the bad one.
+	 * Current consensus on the mailing list is to generate a PROTOCOL
+	 * VIOLATION error.  We build the ERROR chunk here and let the normal
+	 * error handling code build and send the packet.
+	 */
+	if (param.v != (void *)chunk->chunk_end)
+		return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
+
+	/* The only missing mandatory param possible today is
+	 * the state cookie for an INIT-ACK chunk.
+	 */
+	if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
+		return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
+						  chunk, errp);
+
+	/* Verify all the variable length parameters */
+	sctp_walk_params(param, peer_init, init_hdr.params) {
+		result = sctp_verify_param(net, ep, asoc, param, cid,
+					   chunk, errp);
+		switch (result) {
+		case SCTP_IERROR_ABORT:
+		case SCTP_IERROR_NOMEM:
+			return 0;
+		case SCTP_IERROR_ERROR:
+			return 1;
+		case SCTP_IERROR_NO_ERROR:
+		default:
+			break;
+		}
+
+	} /* for (loop through all parameters) */
+
+	return 1;
+}
+
+/* Unpack the parameters in an INIT packet into an association.
+ * Returns 0 on failure, else success.
+ * FIXME:  This is an association method.
+ */
+int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
+		      const union sctp_addr *peer_addr,
+		      struct sctp_init_chunk *peer_init, gfp_t gfp)
+{
+	struct sctp_transport *transport;
+	struct list_head *pos, *temp;
+	union sctp_params param;
+	union sctp_addr addr;
+	struct sctp_af *af;
+	int src_match = 0;
+
+	/* We must include the address that the INIT packet came from.
+	 * This is the only address that matters for an INIT packet.
+	 * When processing a COOKIE ECHO, we retrieve the from address
+	 * of the INIT from the cookie.
+	 */
+
+	/* This implementation defaults to making the first transport
+	 * added as the primary transport.  The source address seems to
+	 * be a better choice than any of the embedded addresses.
+	 */
+	if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
+		goto nomem;
+
+	if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
+		src_match = 1;
+
+	/* Process the initialization parameters.  */
+	sctp_walk_params(param, peer_init, init_hdr.params) {
+		if (!src_match &&
+		    (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
+		     param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
+			af = sctp_get_af_specific(param_type2af(param.p->type));
+			if (!af->from_addr_param(&addr, param.addr,
+						 chunk->sctp_hdr->source, 0))
+				continue;
+			if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
+				src_match = 1;
+		}
+
+		if (!sctp_process_param(asoc, param, peer_addr, gfp))
+			goto clean_up;
+	}
+
+	/* source address of chunk may not match any valid address */
+	if (!src_match)
+		goto clean_up;
+
+	/* AUTH: After processing the parameters, make sure that we
+	 * have all the required info to potentially do authentications.
+	 */
+	if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
+					!asoc->peer.peer_hmacs))
+		asoc->peer.auth_capable = 0;
+
+	/* In a non-backward compatible mode, if the peer claims
+	 * support for ADD-IP but not AUTH,  the ADD-IP spec states
+	 * that we MUST ABORT the association. Section 6.  The section
+	 * also give us an option to silently ignore the packet, which
+	 * is what we'll do here.
+	 */
+	if (!asoc->base.net->sctp.addip_noauth &&
+	    (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
+		asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
+						  SCTP_PARAM_DEL_IP |
+						  SCTP_PARAM_SET_PRIMARY);
+		asoc->peer.asconf_capable = 0;
+		goto clean_up;
+	}
+
+	/* Walk list of transports, removing transports in the UNKNOWN state. */
+	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
+		transport = list_entry(pos, struct sctp_transport, transports);
+		if (transport->state == SCTP_UNKNOWN) {
+			sctp_assoc_rm_peer(asoc, transport);
+		}
+	}
+
+	/* The fixed INIT headers are always in network byte
+	 * order.
+	 */
+	asoc->peer.i.init_tag =
+		ntohl(peer_init->init_hdr.init_tag);
+	asoc->peer.i.a_rwnd =
+		ntohl(peer_init->init_hdr.a_rwnd);
+	asoc->peer.i.num_outbound_streams =
+		ntohs(peer_init->init_hdr.num_outbound_streams);
+	asoc->peer.i.num_inbound_streams =
+		ntohs(peer_init->init_hdr.num_inbound_streams);
+	asoc->peer.i.initial_tsn =
+		ntohl(peer_init->init_hdr.initial_tsn);
+
+	asoc->strreset_inseq = asoc->peer.i.initial_tsn;
+
+	/* Apply the upper bounds for output streams based on peer's
+	 * number of inbound streams.
+	 */
+	if (asoc->c.sinit_num_ostreams  >
+	    ntohs(peer_init->init_hdr.num_inbound_streams)) {
+		asoc->c.sinit_num_ostreams =
+			ntohs(peer_init->init_hdr.num_inbound_streams);
+	}
+
+	if (asoc->c.sinit_max_instreams >
+	    ntohs(peer_init->init_hdr.num_outbound_streams)) {
+		asoc->c.sinit_max_instreams =
+			ntohs(peer_init->init_hdr.num_outbound_streams);
+	}
+
+	/* Copy Initiation tag from INIT to VT_peer in cookie.   */
+	asoc->c.peer_vtag = asoc->peer.i.init_tag;
+
+	/* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
+	asoc->peer.rwnd = asoc->peer.i.a_rwnd;
+
+	/* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
+	 * high (for example, implementations MAY use the size of the receiver
+	 * advertised window).
+	 */
+	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
+			transports) {
+		transport->ssthresh = asoc->peer.i.a_rwnd;
+	}
+
+	/* Set up the TSN tracking pieces.  */
+	if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
+				asoc->peer.i.initial_tsn, gfp))
+		goto clean_up;
+
+	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
+	 *
+	 * The stream sequence number in all the streams shall start
+	 * from 0 when the association is established.  Also, when the
+	 * stream sequence number reaches the value 65535 the next
+	 * stream sequence number shall be set to 0.
+	 */
+
+	if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
+			     asoc->c.sinit_max_instreams, gfp))
+		goto clean_up;
+
+	/* Update frag_point when stream_interleave may get changed. */
+	sctp_assoc_update_frag_point(asoc);
+
+	if (!asoc->temp && sctp_assoc_set_id(asoc, gfp))
+		goto clean_up;
+
+	/* ADDIP Section 4.1 ASCONF Chunk Procedures
+	 *
+	 * When an endpoint has an ASCONF signaled change to be sent to the
+	 * remote endpoint it should do the following:
+	 * ...
+	 * A2) A serial number should be assigned to the Chunk. The serial
+	 * number should be a monotonically increasing number. All serial
+	 * numbers are defined to be initialized at the start of the
+	 * association to the same value as the Initial TSN.
+	 */
+	asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
+	return 1;
+
+clean_up:
+	/* Release the transport structures. */
+	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
+		transport = list_entry(pos, struct sctp_transport, transports);
+		if (transport->state != SCTP_ACTIVE)
+			sctp_assoc_rm_peer(asoc, transport);
+	}
+
+nomem:
+	return 0;
+}
+
+
+/* Update asoc with the option described in param.
+ *
+ * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
+ *
+ * asoc is the association to update.
+ * param is the variable length parameter to use for update.
+ * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
+ * If the current packet is an INIT we want to minimize the amount of
+ * work we do.  In particular, we should not build transport
+ * structures for the addresses.
+ */
+static int sctp_process_param(struct sctp_association *asoc,
+			      union sctp_params param,
+			      const union sctp_addr *peer_addr,
+			      gfp_t gfp)
+{
+	struct sctp_endpoint *ep = asoc->ep;
+	union sctp_addr_param *addr_param;
+	struct net *net = asoc->base.net;
+	struct sctp_transport *t;
+	enum sctp_scope scope;
+	union sctp_addr addr;
+	struct sctp_af *af;
+	int retval = 1, i;
+	u32 stale;
+	__u16 sat;
+
+	/* We maintain all INIT parameters in network byte order all the
+	 * time.  This allows us to not worry about whether the parameters
+	 * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
+	 */
+	switch (param.p->type) {
+	case SCTP_PARAM_IPV6_ADDRESS:
+		if (PF_INET6 != asoc->base.sk->sk_family)
+			break;
+		goto do_addr_param;
+
+	case SCTP_PARAM_IPV4_ADDRESS:
+		/* v4 addresses are not allowed on v6-only socket */
+		if (ipv6_only_sock(asoc->base.sk))
+			break;
+do_addr_param:
+		af = sctp_get_af_specific(param_type2af(param.p->type));
+		if (!af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0))
+			break;
+		scope = sctp_scope(peer_addr);
+		if (sctp_in_scope(net, &addr, scope))
+			if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
+				return 0;
+		break;
+
+	case SCTP_PARAM_COOKIE_PRESERVATIVE:
+		if (!net->sctp.cookie_preserve_enable)
+			break;
+
+		stale = ntohl(param.life->lifespan_increment);
+
+		/* Suggested Cookie Life span increment's unit is msec,
+		 * (1/1000sec).
+		 */
+		asoc->cookie_life = ktime_add_ms(asoc->cookie_life, stale);
+		break;
+
+	case SCTP_PARAM_HOST_NAME_ADDRESS:
+		pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
+		break;
+
+	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
+		/* Turn off the default values first so we'll know which
+		 * ones are really set by the peer.
+		 */
+		asoc->peer.ipv4_address = 0;
+		asoc->peer.ipv6_address = 0;
+
+		/* Assume that peer supports the address family
+		 * by which it sends a packet.
+		 */
+		if (peer_addr->sa.sa_family == AF_INET6)
+			asoc->peer.ipv6_address = 1;
+		else if (peer_addr->sa.sa_family == AF_INET)
+			asoc->peer.ipv4_address = 1;
+
+		/* Cycle through address types; avoid divide by 0. */
+		sat = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
+		if (sat)
+			sat /= sizeof(__u16);
+
+		for (i = 0; i < sat; ++i) {
+			switch (param.sat->types[i]) {
+			case SCTP_PARAM_IPV4_ADDRESS:
+				asoc->peer.ipv4_address = 1;
+				break;
+
+			case SCTP_PARAM_IPV6_ADDRESS:
+				if (PF_INET6 == asoc->base.sk->sk_family)
+					asoc->peer.ipv6_address = 1;
+				break;
+
+			case SCTP_PARAM_HOST_NAME_ADDRESS:
+				asoc->peer.hostname_address = 1;
+				break;
+
+			default: /* Just ignore anything else.  */
+				break;
+			}
+		}
+		break;
+
+	case SCTP_PARAM_STATE_COOKIE:
+		asoc->peer.cookie_len =
+			ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
+		kfree(asoc->peer.cookie);
+		asoc->peer.cookie = kmemdup(param.cookie->body, asoc->peer.cookie_len, gfp);
+		if (!asoc->peer.cookie)
+			retval = 0;
+		break;
+
+	case SCTP_PARAM_HEARTBEAT_INFO:
+		/* Would be odd to receive, but it causes no problems. */
+		break;
+
+	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
+		/* Rejected during verify stage. */
+		break;
+
+	case SCTP_PARAM_ECN_CAPABLE:
+		if (asoc->ep->ecn_enable) {
+			asoc->peer.ecn_capable = 1;
+			break;
+		}
+		/* Fall Through */
+		goto fall_through;
+
+
+	case SCTP_PARAM_ADAPTATION_LAYER_IND:
+		asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
+		break;
+
+	case SCTP_PARAM_SET_PRIMARY:
+		if (!ep->asconf_enable)
+			goto fall_through;
+
+		addr_param = param.v + sizeof(struct sctp_addip_param);
+
+		af = sctp_get_af_specific(param_type2af(addr_param->p.type));
+		if (!af)
+			break;
+
+		if (!af->from_addr_param(&addr, addr_param,
+					 htons(asoc->peer.port), 0))
+			break;
+
+		if (!af->addr_valid(&addr, NULL, NULL))
+			break;
+
+		t = sctp_assoc_lookup_paddr(asoc, &addr);
+		if (!t)
+			break;
+
+		sctp_assoc_set_primary(asoc, t);
+		break;
+
+	case SCTP_PARAM_SUPPORTED_EXT:
+		sctp_process_ext_param(asoc, param);
+		break;
+
+	case SCTP_PARAM_FWD_TSN_SUPPORT:
+		if (asoc->ep->prsctp_enable) {
+			asoc->peer.prsctp_capable = 1;
+			break;
+		}
+		/* Fall Through */
+		goto fall_through;
+
+	case SCTP_PARAM_RANDOM:
+		if (!ep->auth_enable)
+			goto fall_through;
+
+		/* Save peer's random parameter */
+		kfree(asoc->peer.peer_random);
+		asoc->peer.peer_random = kmemdup(param.p,
+					    ntohs(param.p->length), gfp);
+		if (!asoc->peer.peer_random) {
+			retval = 0;
+			break;
+		}
+		break;
+
+	case SCTP_PARAM_HMAC_ALGO:
+		if (!ep->auth_enable)
+			goto fall_through;
+
+		/* Save peer's HMAC list */
+		kfree(asoc->peer.peer_hmacs);
+		asoc->peer.peer_hmacs = kmemdup(param.p,
+					    ntohs(param.p->length), gfp);
+		if (!asoc->peer.peer_hmacs) {
+			retval = 0;
+			break;
+		}
+
+		/* Set the default HMAC the peer requested*/
+		sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
+		break;
+
+	case SCTP_PARAM_CHUNKS:
+		if (!ep->auth_enable)
+			goto fall_through;
+
+		kfree(asoc->peer.peer_chunks);
+		asoc->peer.peer_chunks = kmemdup(param.p,
+					    ntohs(param.p->length), gfp);
+		if (!asoc->peer.peer_chunks)
+			retval = 0;
+		break;
+fall_through:
+	default:
+		/* Any unrecognized parameters should have been caught
+		 * and handled by sctp_verify_param() which should be
+		 * called prior to this routine.  Simply log the error
+		 * here.
+		 */
+		pr_debug("%s: ignoring param:%d for association:%p.\n",
+			 __func__, ntohs(param.p->type), asoc);
+		break;
+	}
+
+	return retval;
+}
+
+/* Select a new verification tag.  */
+__u32 sctp_generate_tag(const struct sctp_endpoint *ep)
+{
+	/* I believe that this random number generator complies with RFC1750.
+	 * A tag of 0 is reserved for special cases (e.g. INIT).
+	 */
+	__u32 x;
+
+	do {
+		get_random_bytes(&x, sizeof(__u32));
+	} while (x == 0);
+
+	return x;
+}
+
+/* Select an initial TSN to send during startup.  */
+__u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
+{
+	__u32 retval;
+
+	get_random_bytes(&retval, sizeof(__u32));
+	return retval;
+}
+
+/*
+ * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
+ *      0                   1                   2                   3
+ *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                       Serial Number                           |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                    Address Parameter                          |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                     ASCONF Parameter #1                       |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     \                                                               \
+ *     /                             ....                              /
+ *     \                                                               \
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                     ASCONF Parameter #N                       |
+ *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Address Parameter and other parameter will not be wrapped in this function
+ */
+static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
+					   union sctp_addr *addr,
+					   int vparam_len)
+{
+	struct sctp_addiphdr asconf;
+	struct sctp_chunk *retval;
+	int length = sizeof(asconf) + vparam_len;
+	union sctp_addr_param addrparam;
+	int addrlen;
+	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
+
+	addrlen = af->to_addr_param(addr, &addrparam);
+	if (!addrlen)
+		return NULL;
+	length += addrlen;
+
+	/* Create the chunk.  */
+	retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length,
+				   GFP_ATOMIC);
+	if (!retval)
+		return NULL;
+
+	asconf.serial = htonl(asoc->addip_serial++);
+
+	retval->subh.addip_hdr =
+		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
+	retval->param_hdr.v =
+		sctp_addto_chunk(retval, addrlen, &addrparam);
+
+	return retval;
+}
+
+/* ADDIP
+ * 3.2.1 Add IP Address
+ * 	0                   1                   2                   3
+ * 	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |        Type = 0xC001          |    Length = Variable          |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |               ASCONF-Request Correlation ID                   |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                       Address Parameter                       |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * 3.2.2 Delete IP Address
+ * 	0                   1                   2                   3
+ * 	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |        Type = 0xC002          |    Length = Variable          |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |               ASCONF-Request Correlation ID                   |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                       Address Parameter                       |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ */
+struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
+					      union sctp_addr *laddr,
+					      struct sockaddr *addrs,
+					      int addrcnt, __be16 flags)
+{
+	union sctp_addr_param addr_param;
+	struct sctp_addip_param	param;
+	int paramlen = sizeof(param);
+	struct sctp_chunk *retval;
+	int addr_param_len = 0;
+	union sctp_addr *addr;
+	int totallen = 0, i;
+	int del_pickup = 0;
+	struct sctp_af *af;
+	void *addr_buf;
+
+	/* Get total length of all the address parameters. */
+	addr_buf = addrs;
+	for (i = 0; i < addrcnt; i++) {
+		addr = addr_buf;
+		af = sctp_get_af_specific(addr->v4.sin_family);
+		addr_param_len = af->to_addr_param(addr, &addr_param);
+
+		totallen += paramlen;
+		totallen += addr_param_len;
+
+		addr_buf += af->sockaddr_len;
+		if (asoc->asconf_addr_del_pending && !del_pickup) {
+			/* reuse the parameter length from the same scope one */
+			totallen += paramlen;
+			totallen += addr_param_len;
+			del_pickup = 1;
+
+			pr_debug("%s: picked same-scope del_pending addr, "
+				 "totallen for all addresses is %d\n",
+				 __func__, totallen);
+		}
+	}
+
+	/* Create an asconf chunk with the required length. */
+	retval = sctp_make_asconf(asoc, laddr, totallen);
+	if (!retval)
+		return NULL;
+
+	/* Add the address parameters to the asconf chunk. */
+	addr_buf = addrs;
+	for (i = 0; i < addrcnt; i++) {
+		addr = addr_buf;
+		af = sctp_get_af_specific(addr->v4.sin_family);
+		addr_param_len = af->to_addr_param(addr, &addr_param);
+		param.param_hdr.type = flags;
+		param.param_hdr.length = htons(paramlen + addr_param_len);
+		param.crr_id = htonl(i);
+
+		sctp_addto_chunk(retval, paramlen, &param);
+		sctp_addto_chunk(retval, addr_param_len, &addr_param);
+
+		addr_buf += af->sockaddr_len;
+	}
+	if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
+		addr = asoc->asconf_addr_del_pending;
+		af = sctp_get_af_specific(addr->v4.sin_family);
+		addr_param_len = af->to_addr_param(addr, &addr_param);
+		param.param_hdr.type = SCTP_PARAM_DEL_IP;
+		param.param_hdr.length = htons(paramlen + addr_param_len);
+		param.crr_id = htonl(i);
+
+		sctp_addto_chunk(retval, paramlen, &param);
+		sctp_addto_chunk(retval, addr_param_len, &addr_param);
+	}
+	return retval;
+}
+
+/* ADDIP
+ * 3.2.4 Set Primary IP Address
+ *	0                   1                   2                   3
+ *	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |        Type =0xC004           |    Length = Variable          |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |               ASCONF-Request Correlation ID                   |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                       Address Parameter                       |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Create an ASCONF chunk with Set Primary IP address parameter.
+ */
+struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
+					     union sctp_addr *addr)
+{
+	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
+	union sctp_addr_param addrparam;
+	struct sctp_addip_param	param;
+	struct sctp_chunk *retval;
+	int len = sizeof(param);
+	int addrlen;
+
+	addrlen = af->to_addr_param(addr, &addrparam);
+	if (!addrlen)
+		return NULL;
+	len += addrlen;
+
+	/* Create the chunk and make asconf header. */
+	retval = sctp_make_asconf(asoc, addr, len);
+	if (!retval)
+		return NULL;
+
+	param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
+	param.param_hdr.length = htons(len);
+	param.crr_id = 0;
+
+	sctp_addto_chunk(retval, sizeof(param), &param);
+	sctp_addto_chunk(retval, addrlen, &addrparam);
+
+	return retval;
+}
+
+/* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
+ *      0                   1                   2                   3
+ *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                       Serial Number                           |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                 ASCONF Parameter Response#1                   |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     \                                                               \
+ *     /                             ....                              /
+ *     \                                                               \
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     |                 ASCONF Parameter Response#N                   |
+ *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Create an ASCONF_ACK chunk with enough space for the parameter responses.
+ */
+static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
+					       __u32 serial, int vparam_len)
+{
+	struct sctp_addiphdr asconf;
+	struct sctp_chunk *retval;
+	int length = sizeof(asconf) + vparam_len;
+
+	/* Create the chunk.  */
+	retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length,
+				   GFP_ATOMIC);
+	if (!retval)
+		return NULL;
+
+	asconf.serial = htonl(serial);
+
+	retval->subh.addip_hdr =
+		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
+
+	return retval;
+}
+
+/* Add response parameters to an ASCONF_ACK chunk. */
+static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
+				     __be16 err_code,
+				     struct sctp_addip_param *asconf_param)
+{
+	struct sctp_addip_param ack_param;
+	struct sctp_errhdr err_param;
+	int asconf_param_len = 0;
+	int err_param_len = 0;
+	__be16 response_type;
+
+	if (SCTP_ERROR_NO_ERROR == err_code) {
+		response_type = SCTP_PARAM_SUCCESS_REPORT;
+	} else {
+		response_type = SCTP_PARAM_ERR_CAUSE;
+		err_param_len = sizeof(err_param);
+		if (asconf_param)
+			asconf_param_len =
+				 ntohs(asconf_param->param_hdr.length);
+	}
+
+	/* Add Success Indication or Error Cause Indication parameter. */
+	ack_param.param_hdr.type = response_type;
+	ack_param.param_hdr.length = htons(sizeof(ack_param) +
+					   err_param_len +
+					   asconf_param_len);
+	ack_param.crr_id = crr_id;
+	sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
+
+	if (SCTP_ERROR_NO_ERROR == err_code)
+		return;
+
+	/* Add Error Cause parameter. */
+	err_param.cause = err_code;
+	err_param.length = htons(err_param_len + asconf_param_len);
+	sctp_addto_chunk(chunk, err_param_len, &err_param);
+
+	/* Add the failed TLV copied from ASCONF chunk. */
+	if (asconf_param)
+		sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
+}
+
+/* Process a asconf parameter. */
+static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
+					struct sctp_chunk *asconf,
+					struct sctp_addip_param *asconf_param)
+{
+	union sctp_addr_param *addr_param;
+	struct sctp_transport *peer;
+	union sctp_addr	addr;
+	struct sctp_af *af;
+
+	addr_param = (void *)asconf_param + sizeof(*asconf_param);
+
+	if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
+	    asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
+	    asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
+		return SCTP_ERROR_UNKNOWN_PARAM;
+
+	switch (addr_param->p.type) {
+	case SCTP_PARAM_IPV6_ADDRESS:
+		if (!asoc->peer.ipv6_address)
+			return SCTP_ERROR_DNS_FAILED;
+		break;
+	case SCTP_PARAM_IPV4_ADDRESS:
+		if (!asoc->peer.ipv4_address)
+			return SCTP_ERROR_DNS_FAILED;
+		break;
+	default:
+		return SCTP_ERROR_DNS_FAILED;
+	}
+
+	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
+	if (unlikely(!af))
+		return SCTP_ERROR_DNS_FAILED;
+
+	if (!af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0))
+		return SCTP_ERROR_DNS_FAILED;
+
+	/* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
+	 * or multicast address.
+	 * (note: wildcard is permitted and requires special handling so
+	 *  make sure we check for that)
+	 */
+	if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
+		return SCTP_ERROR_DNS_FAILED;
+
+	switch (asconf_param->param_hdr.type) {
+	case SCTP_PARAM_ADD_IP:
+		/* Section 4.2.1:
+		 * If the address 0.0.0.0 or ::0 is provided, the source
+		 * address of the packet MUST be added.
+		 */
+		if (af->is_any(&addr))
+			memcpy(&addr, &asconf->source, sizeof(addr));
+
+		if (security_sctp_bind_connect(asoc->ep->base.sk,
+					       SCTP_PARAM_ADD_IP,
+					       (struct sockaddr *)&addr,
+					       af->sockaddr_len))
+			return SCTP_ERROR_REQ_REFUSED;
+
+		/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
+		 * request and does not have the local resources to add this
+		 * new address to the association, it MUST return an Error
+		 * Cause TLV set to the new error code 'Operation Refused
+		 * Due to Resource Shortage'.
+		 */
+
+		peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
+		if (!peer)
+			return SCTP_ERROR_RSRC_LOW;
+
+		/* Start the heartbeat timer. */
+		sctp_transport_reset_hb_timer(peer);
+		asoc->new_transport = peer;
+		break;
+	case SCTP_PARAM_DEL_IP:
+		/* ADDIP 4.3 D7) If a request is received to delete the
+		 * last remaining IP address of a peer endpoint, the receiver
+		 * MUST send an Error Cause TLV with the error cause set to the
+		 * new error code 'Request to Delete Last Remaining IP Address'.
+		 */
+		if (asoc->peer.transport_count == 1)
+			return SCTP_ERROR_DEL_LAST_IP;
+
+		/* ADDIP 4.3 D8) If a request is received to delete an IP
+		 * address which is also the source address of the IP packet
+		 * which contained the ASCONF chunk, the receiver MUST reject
+		 * this request. To reject the request the receiver MUST send
+		 * an Error Cause TLV set to the new error code 'Request to
+		 * Delete Source IP Address'
+		 */
+		if (sctp_cmp_addr_exact(&asconf->source, &addr))
+			return SCTP_ERROR_DEL_SRC_IP;
+
+		/* Section 4.2.2
+		 * If the address 0.0.0.0 or ::0 is provided, all
+		 * addresses of the peer except	the source address of the
+		 * packet MUST be deleted.
+		 */
+		if (af->is_any(&addr)) {
+			sctp_assoc_set_primary(asoc, asconf->transport);
+			sctp_assoc_del_nonprimary_peers(asoc,
+							asconf->transport);
+			return SCTP_ERROR_NO_ERROR;
+		}
+
+		/* If the address is not part of the association, the
+		 * ASCONF-ACK with Error Cause Indication Parameter
+		 * which including cause of Unresolvable Address should
+		 * be sent.
+		 */
+		peer = sctp_assoc_lookup_paddr(asoc, &addr);
+		if (!peer)
+			return SCTP_ERROR_DNS_FAILED;
+
+		sctp_assoc_rm_peer(asoc, peer);
+		break;
+	case SCTP_PARAM_SET_PRIMARY:
+		/* ADDIP Section 4.2.4
+		 * If the address 0.0.0.0 or ::0 is provided, the receiver
+		 * MAY mark the source address of the packet as its
+		 * primary.
+		 */
+		if (af->is_any(&addr))
+			memcpy(&addr, sctp_source(asconf), sizeof(addr));
+
+		if (security_sctp_bind_connect(asoc->ep->base.sk,
+					       SCTP_PARAM_SET_PRIMARY,
+					       (struct sockaddr *)&addr,
+					       af->sockaddr_len))
+			return SCTP_ERROR_REQ_REFUSED;
+
+		peer = sctp_assoc_lookup_paddr(asoc, &addr);
+		if (!peer)
+			return SCTP_ERROR_DNS_FAILED;
+
+		sctp_assoc_set_primary(asoc, peer);
+		break;
+	}
+
+	return SCTP_ERROR_NO_ERROR;
+}
+
+/* Verify the ASCONF packet before we process it. */
+bool sctp_verify_asconf(const struct sctp_association *asoc,
+			struct sctp_chunk *chunk, bool addr_param_needed,
+			struct sctp_paramhdr **errp)
+{
+	struct sctp_addip_chunk *addip;
+	bool addr_param_seen = false;
+	union sctp_params param;
+
+	addip = (struct sctp_addip_chunk *)chunk->chunk_hdr;
+	sctp_walk_params(param, addip, addip_hdr.params) {
+		size_t length = ntohs(param.p->length);
+
+		*errp = param.p;
+		switch (param.p->type) {
+		case SCTP_PARAM_ERR_CAUSE:
+			break;
+		case SCTP_PARAM_IPV4_ADDRESS:
+			if (length != sizeof(struct sctp_ipv4addr_param))
+				return false;
+			/* ensure there is only one addr param and it's in the
+			 * beginning of addip_hdr params, or we reject it.
+			 */
+			if (param.v != addip->addip_hdr.params)
+				return false;
+			addr_param_seen = true;
+			break;
+		case SCTP_PARAM_IPV6_ADDRESS:
+			if (length != sizeof(struct sctp_ipv6addr_param))
+				return false;
+			if (param.v != addip->addip_hdr.params)
+				return false;
+			addr_param_seen = true;
+			break;
+		case SCTP_PARAM_ADD_IP:
+		case SCTP_PARAM_DEL_IP:
+		case SCTP_PARAM_SET_PRIMARY:
+			/* In ASCONF chunks, these need to be first. */
+			if (addr_param_needed && !addr_param_seen)
+				return false;
+			length = ntohs(param.addip->param_hdr.length);
+			if (length < sizeof(struct sctp_addip_param) +
+				     sizeof(**errp))
+				return false;
+			break;
+		case SCTP_PARAM_SUCCESS_REPORT:
+		case SCTP_PARAM_ADAPTATION_LAYER_IND:
+			if (length != sizeof(struct sctp_addip_param))
+				return false;
+			break;
+		default:
+			/* This is unkown to us, reject! */
+			return false;
+		}
+	}
+
+	/* Remaining sanity checks. */
+	if (addr_param_needed && !addr_param_seen)
+		return false;
+	if (!addr_param_needed && addr_param_seen)
+		return false;
+	if (param.v != chunk->chunk_end)
+		return false;
+
+	return true;
+}
+
+/* Process an incoming ASCONF chunk with the next expected serial no. and
+ * return an ASCONF_ACK chunk to be sent in response.
+ */
+struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
+				       struct sctp_chunk *asconf)
+{
+	union sctp_addr_param *addr_param;
+	struct sctp_addip_chunk *addip;
+	struct sctp_chunk *asconf_ack;
+	bool all_param_pass = true;
+	struct sctp_addiphdr *hdr;
+	int length = 0, chunk_len;
+	union sctp_params param;
+	__be16 err_code;
+	__u32 serial;
+
+	addip = (struct sctp_addip_chunk *)asconf->chunk_hdr;
+	chunk_len = ntohs(asconf->chunk_hdr->length) -
+		    sizeof(struct sctp_chunkhdr);
+	hdr = (struct sctp_addiphdr *)asconf->skb->data;
+	serial = ntohl(hdr->serial);
+
+	/* Skip the addiphdr and store a pointer to address parameter.  */
+	length = sizeof(*hdr);
+	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
+	chunk_len -= length;
+
+	/* Skip the address parameter and store a pointer to the first
+	 * asconf parameter.
+	 */
+	length = ntohs(addr_param->p.length);
+	chunk_len -= length;
+
+	/* create an ASCONF_ACK chunk.
+	 * Based on the definitions of parameters, we know that the size of
+	 * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
+	 * parameters.
+	 */
+	asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
+	if (!asconf_ack)
+		goto done;
+
+	/* Process the TLVs contained within the ASCONF chunk. */
+	sctp_walk_params(param, addip, addip_hdr.params) {
+		/* Skip preceeding address parameters. */
+		if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
+		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)
+			continue;
+
+		err_code = sctp_process_asconf_param(asoc, asconf,
+						     param.addip);
+		/* ADDIP 4.1 A7)
+		 * If an error response is received for a TLV parameter,
+		 * all TLVs with no response before the failed TLV are
+		 * considered successful if not reported.  All TLVs after
+		 * the failed response are considered unsuccessful unless
+		 * a specific success indication is present for the parameter.
+		 */
+		if (err_code != SCTP_ERROR_NO_ERROR)
+			all_param_pass = false;
+		if (!all_param_pass)
+			sctp_add_asconf_response(asconf_ack, param.addip->crr_id,
+						 err_code, param.addip);
+
+		/* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
+		 * an IP address sends an 'Out of Resource' in its response, it
+		 * MUST also fail any subsequent add or delete requests bundled
+		 * in the ASCONF.
+		 */
+		if (err_code == SCTP_ERROR_RSRC_LOW)
+			goto done;
+	}
+done:
+	asoc->peer.addip_serial++;
+
+	/* If we are sending a new ASCONF_ACK hold a reference to it in assoc
+	 * after freeing the reference to old asconf ack if any.
+	 */
+	if (asconf_ack) {
+		sctp_chunk_hold(asconf_ack);
+		list_add_tail(&asconf_ack->transmitted_list,
+			      &asoc->asconf_ack_list);
+	}
+
+	return asconf_ack;
+}
+
+/* Process a asconf parameter that is successfully acked. */
+static void sctp_asconf_param_success(struct sctp_association *asoc,
+				      struct sctp_addip_param *asconf_param)
+{
+	struct sctp_bind_addr *bp = &asoc->base.bind_addr;
+	union sctp_addr_param *addr_param;
+	struct sctp_sockaddr_entry *saddr;
+	struct sctp_transport *transport;
+	union sctp_addr	addr;
+	struct sctp_af *af;
+
+	addr_param = (void *)asconf_param + sizeof(*asconf_param);
+
+	/* We have checked the packet before, so we do not check again.	*/
+	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
+	if (!af->from_addr_param(&addr, addr_param, htons(bp->port), 0))
+		return;
+
+	switch (asconf_param->param_hdr.type) {
+	case SCTP_PARAM_ADD_IP:
+		/* This is always done in BH context with a socket lock
+		 * held, so the list can not change.
+		 */
+		local_bh_disable();
+		list_for_each_entry(saddr, &bp->address_list, list) {
+			if (sctp_cmp_addr_exact(&saddr->a, &addr))
+				saddr->state = SCTP_ADDR_SRC;
+		}
+		local_bh_enable();
+		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
+				transports) {
+			sctp_transport_dst_release(transport);
+		}
+		break;
+	case SCTP_PARAM_DEL_IP:
+		local_bh_disable();
+		sctp_del_bind_addr(bp, &addr);
+		if (asoc->asconf_addr_del_pending != NULL &&
+		    sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
+			kfree(asoc->asconf_addr_del_pending);
+			asoc->asconf_addr_del_pending = NULL;
+		}
+		local_bh_enable();
+		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
+				transports) {
+			sctp_transport_dst_release(transport);
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+/* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
+ * for the given asconf parameter.  If there is no response for this parameter,
+ * return the error code based on the third argument 'no_err'.
+ * ADDIP 4.1
+ * A7) If an error response is received for a TLV parameter, all TLVs with no
+ * response before the failed TLV are considered successful if not reported.
+ * All TLVs after the failed response are considered unsuccessful unless a
+ * specific success indication is present for the parameter.
+ */
+static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
+				       struct sctp_addip_param *asconf_param,
+				       int no_err)
+{
+	struct sctp_addip_param	*asconf_ack_param;
+	struct sctp_errhdr *err_param;
+	int asconf_ack_len;
+	__be16 err_code;
+	int length;
+
+	if (no_err)
+		err_code = SCTP_ERROR_NO_ERROR;
+	else
+		err_code = SCTP_ERROR_REQ_REFUSED;
+
+	asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
+			 sizeof(struct sctp_chunkhdr);
+
+	/* Skip the addiphdr from the asconf_ack chunk and store a pointer to
+	 * the first asconf_ack parameter.
+	 */
+	length = sizeof(struct sctp_addiphdr);
+	asconf_ack_param = (struct sctp_addip_param *)(asconf_ack->skb->data +
+						       length);
+	asconf_ack_len -= length;
+
+	while (asconf_ack_len > 0) {
+		if (asconf_ack_param->crr_id == asconf_param->crr_id) {
+			switch (asconf_ack_param->param_hdr.type) {
+			case SCTP_PARAM_SUCCESS_REPORT:
+				return SCTP_ERROR_NO_ERROR;
+			case SCTP_PARAM_ERR_CAUSE:
+				length = sizeof(*asconf_ack_param);
+				err_param = (void *)asconf_ack_param + length;
+				asconf_ack_len -= length;
+				if (asconf_ack_len > 0)
+					return err_param->cause;
+				else
+					return SCTP_ERROR_INV_PARAM;
+				break;
+			default:
+				return SCTP_ERROR_INV_PARAM;
+			}
+		}
+
+		length = ntohs(asconf_ack_param->param_hdr.length);
+		asconf_ack_param = (void *)asconf_ack_param + length;
+		asconf_ack_len -= length;
+	}
+
+	return err_code;
+}
+
+/* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
+int sctp_process_asconf_ack(struct sctp_association *asoc,
+			    struct sctp_chunk *asconf_ack)
+{
+	struct sctp_chunk *asconf = asoc->addip_last_asconf;
+	struct sctp_addip_param *asconf_param;
+	__be16 err_code = SCTP_ERROR_NO_ERROR;
+	union sctp_addr_param *addr_param;
+	int asconf_len = asconf->skb->len;
+	int all_param_pass = 0;
+	int length = 0;
+	int no_err = 1;
+	int retval = 0;
+
+	/* Skip the chunkhdr and addiphdr from the last asconf sent and store
+	 * a pointer to address parameter.
+	 */
+	length = sizeof(struct sctp_addip_chunk);
+	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
+	asconf_len -= length;
+
+	/* Skip the address parameter in the last asconf sent and store a
+	 * pointer to the first asconf parameter.
+	 */
+	length = ntohs(addr_param->p.length);
+	asconf_param = (void *)addr_param + length;
+	asconf_len -= length;
+
+	/* ADDIP 4.1
+	 * A8) If there is no response(s) to specific TLV parameter(s), and no
+	 * failures are indicated, then all request(s) are considered
+	 * successful.
+	 */
+	if (asconf_ack->skb->len == sizeof(struct sctp_addiphdr))
+		all_param_pass = 1;
+
+	/* Process the TLVs contained in the last sent ASCONF chunk. */
+	while (asconf_len > 0) {
+		if (all_param_pass)
+			err_code = SCTP_ERROR_NO_ERROR;
+		else {
+			err_code = sctp_get_asconf_response(asconf_ack,
+							    asconf_param,
+							    no_err);
+			if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
+				no_err = 0;
+		}
+
+		switch (err_code) {
+		case SCTP_ERROR_NO_ERROR:
+			sctp_asconf_param_success(asoc, asconf_param);
+			break;
+
+		case SCTP_ERROR_RSRC_LOW:
+			retval = 1;
+			break;
+
+		case SCTP_ERROR_UNKNOWN_PARAM:
+			/* Disable sending this type of asconf parameter in
+			 * future.
+			 */
+			asoc->peer.addip_disabled_mask |=
+				asconf_param->param_hdr.type;
+			break;
+
+		case SCTP_ERROR_REQ_REFUSED:
+		case SCTP_ERROR_DEL_LAST_IP:
+		case SCTP_ERROR_DEL_SRC_IP:
+		default:
+			 break;
+		}
+
+		/* Skip the processed asconf parameter and move to the next
+		 * one.
+		 */
+		length = ntohs(asconf_param->param_hdr.length);
+		asconf_param = (void *)asconf_param + length;
+		asconf_len -= length;
+	}
+
+	if (no_err && asoc->src_out_of_asoc_ok) {
+		asoc->src_out_of_asoc_ok = 0;
+		sctp_transport_immediate_rtx(asoc->peer.primary_path);
+	}
+
+	/* Free the cached last sent asconf chunk. */
+	list_del_init(&asconf->transmitted_list);
+	sctp_chunk_free(asconf);
+	asoc->addip_last_asconf = NULL;
+
+	return retval;
+}
+
+/* Make a FWD TSN chunk. */
+struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
+				    __u32 new_cum_tsn, size_t nstreams,
+				    struct sctp_fwdtsn_skip *skiplist)
+{
+	struct sctp_chunk *retval = NULL;
+	struct sctp_fwdtsn_hdr ftsn_hdr;
+	struct sctp_fwdtsn_skip skip;
+	size_t hint;
+	int i;
+
+	hint = (nstreams + 1) * sizeof(__u32);
+
+	retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint, GFP_ATOMIC);
+
+	if (!retval)
+		return NULL;
+
+	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
+	retval->subh.fwdtsn_hdr =
+		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
+
+	for (i = 0; i < nstreams; i++) {
+		skip.stream = skiplist[i].stream;
+		skip.ssn = skiplist[i].ssn;
+		sctp_addto_chunk(retval, sizeof(skip), &skip);
+	}
+
+	return retval;
+}
+
+struct sctp_chunk *sctp_make_ifwdtsn(const struct sctp_association *asoc,
+				     __u32 new_cum_tsn, size_t nstreams,
+				     struct sctp_ifwdtsn_skip *skiplist)
+{
+	struct sctp_chunk *retval = NULL;
+	struct sctp_ifwdtsn_hdr ftsn_hdr;
+	size_t hint;
+
+	hint = (nstreams + 1) * sizeof(__u32);
+
+	retval = sctp_make_control(asoc, SCTP_CID_I_FWD_TSN, 0, hint,
+				   GFP_ATOMIC);
+	if (!retval)
+		return NULL;
+
+	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
+	retval->subh.ifwdtsn_hdr =
+		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
+
+	sctp_addto_chunk(retval, nstreams * sizeof(skiplist[0]), skiplist);
+
+	return retval;
+}
+
+/* RE-CONFIG 3.1 (RE-CONFIG chunk)
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  | Type = 130    |  Chunk Flags  |      Chunk Length             |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  \                                                               \
+ *  /                  Re-configuration Parameter                   /
+ *  \                                                               \
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  \                                                               \
+ *  /             Re-configuration Parameter (optional)             /
+ *  \                                                               \
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+static struct sctp_chunk *sctp_make_reconf(const struct sctp_association *asoc,
+					   int length)
+{
+	struct sctp_reconf_chunk *reconf;
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_control(asoc, SCTP_CID_RECONF, 0, length,
+				   GFP_ATOMIC);
+	if (!retval)
+		return NULL;
+
+	reconf = (struct sctp_reconf_chunk *)retval->chunk_hdr;
+	retval->param_hdr.v = reconf->params;
+
+	return retval;
+}
+
+/* RE-CONFIG 4.1 (STREAM OUT RESET)
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |     Parameter Type = 13       | Parameter Length = 16 + 2 * N |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |           Re-configuration Request Sequence Number            |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |           Re-configuration Response Sequence Number           |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |                Sender's Last Assigned TSN                     |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  /                            ......                             /
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * RE-CONFIG 4.2 (STREAM IN RESET)
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |     Parameter Type = 14       |  Parameter Length = 8 + 2 * N |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |          Re-configuration Request Sequence Number             |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  /                            ......                             /
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+struct sctp_chunk *sctp_make_strreset_req(
+					const struct sctp_association *asoc,
+					__u16 stream_num, __be16 *stream_list,
+					bool out, bool in)
+{
+	__u16 stream_len = stream_num * sizeof(__u16);
+	struct sctp_strreset_outreq outreq;
+	struct sctp_strreset_inreq inreq;
+	struct sctp_chunk *retval;
+	__u16 outlen, inlen;
+
+	outlen = (sizeof(outreq) + stream_len) * out;
+	inlen = (sizeof(inreq) + stream_len) * in;
+
+	retval = sctp_make_reconf(asoc, SCTP_PAD4(outlen) + SCTP_PAD4(inlen));
+	if (!retval)
+		return NULL;
+
+	if (outlen) {
+		outreq.param_hdr.type = SCTP_PARAM_RESET_OUT_REQUEST;
+		outreq.param_hdr.length = htons(outlen);
+		outreq.request_seq = htonl(asoc->strreset_outseq);
+		outreq.response_seq = htonl(asoc->strreset_inseq - 1);
+		outreq.send_reset_at_tsn = htonl(asoc->next_tsn - 1);
+
+		sctp_addto_chunk(retval, sizeof(outreq), &outreq);
+
+		if (stream_len)
+			sctp_addto_chunk(retval, stream_len, stream_list);
+	}
+
+	if (inlen) {
+		inreq.param_hdr.type = SCTP_PARAM_RESET_IN_REQUEST;
+		inreq.param_hdr.length = htons(inlen);
+		inreq.request_seq = htonl(asoc->strreset_outseq + out);
+
+		sctp_addto_chunk(retval, sizeof(inreq), &inreq);
+
+		if (stream_len)
+			sctp_addto_chunk(retval, stream_len, stream_list);
+	}
+
+	return retval;
+}
+
+/* RE-CONFIG 4.3 (SSN/TSN RESET ALL)
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |     Parameter Type = 15       |      Parameter Length = 8     |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |         Re-configuration Request Sequence Number              |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+struct sctp_chunk *sctp_make_strreset_tsnreq(
+					const struct sctp_association *asoc)
+{
+	struct sctp_strreset_tsnreq tsnreq;
+	__u16 length = sizeof(tsnreq);
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_reconf(asoc, length);
+	if (!retval)
+		return NULL;
+
+	tsnreq.param_hdr.type = SCTP_PARAM_RESET_TSN_REQUEST;
+	tsnreq.param_hdr.length = htons(length);
+	tsnreq.request_seq = htonl(asoc->strreset_outseq);
+
+	sctp_addto_chunk(retval, sizeof(tsnreq), &tsnreq);
+
+	return retval;
+}
+
+/* RE-CONFIG 4.5/4.6 (ADD STREAM)
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |     Parameter Type = 17       |      Parameter Length = 12    |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |          Re-configuration Request Sequence Number             |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |      Number of new streams    |         Reserved              |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+struct sctp_chunk *sctp_make_strreset_addstrm(
+					const struct sctp_association *asoc,
+					__u16 out, __u16 in)
+{
+	struct sctp_strreset_addstrm addstrm;
+	__u16 size = sizeof(addstrm);
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_reconf(asoc, (!!out + !!in) * size);
+	if (!retval)
+		return NULL;
+
+	if (out) {
+		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_OUT_STREAMS;
+		addstrm.param_hdr.length = htons(size);
+		addstrm.number_of_streams = htons(out);
+		addstrm.request_seq = htonl(asoc->strreset_outseq);
+		addstrm.reserved = 0;
+
+		sctp_addto_chunk(retval, size, &addstrm);
+	}
+
+	if (in) {
+		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_IN_STREAMS;
+		addstrm.param_hdr.length = htons(size);
+		addstrm.number_of_streams = htons(in);
+		addstrm.request_seq = htonl(asoc->strreset_outseq + !!out);
+		addstrm.reserved = 0;
+
+		sctp_addto_chunk(retval, size, &addstrm);
+	}
+
+	return retval;
+}
+
+/* RE-CONFIG 4.4 (RESP)
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |     Parameter Type = 16       |      Parameter Length         |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |         Re-configuration Response Sequence Number             |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |                            Result                             |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+struct sctp_chunk *sctp_make_strreset_resp(const struct sctp_association *asoc,
+					   __u32 result, __u32 sn)
+{
+	struct sctp_strreset_resp resp;
+	__u16 length = sizeof(resp);
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_reconf(asoc, length);
+	if (!retval)
+		return NULL;
+
+	resp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
+	resp.param_hdr.length = htons(length);
+	resp.response_seq = htonl(sn);
+	resp.result = htonl(result);
+
+	sctp_addto_chunk(retval, sizeof(resp), &resp);
+
+	return retval;
+}
+
+/* RE-CONFIG 4.4 OPTIONAL (TSNRESP)
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |     Parameter Type = 16       |      Parameter Length         |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |         Re-configuration Response Sequence Number             |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |                            Result                             |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |                   Sender's Next TSN (optional)                |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |                  Receiver's Next TSN (optional)               |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+struct sctp_chunk *sctp_make_strreset_tsnresp(struct sctp_association *asoc,
+					      __u32 result, __u32 sn,
+					      __u32 sender_tsn,
+					      __u32 receiver_tsn)
+{
+	struct sctp_strreset_resptsn tsnresp;
+	__u16 length = sizeof(tsnresp);
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_reconf(asoc, length);
+	if (!retval)
+		return NULL;
+
+	tsnresp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
+	tsnresp.param_hdr.length = htons(length);
+
+	tsnresp.response_seq = htonl(sn);
+	tsnresp.result = htonl(result);
+	tsnresp.senders_next_tsn = htonl(sender_tsn);
+	tsnresp.receivers_next_tsn = htonl(receiver_tsn);
+
+	sctp_addto_chunk(retval, sizeof(tsnresp), &tsnresp);
+
+	return retval;
+}
+
+bool sctp_verify_reconf(const struct sctp_association *asoc,
+			struct sctp_chunk *chunk,
+			struct sctp_paramhdr **errp)
+{
+	struct sctp_reconf_chunk *hdr;
+	union sctp_params param;
+	__be16 last = 0;
+	__u16 cnt = 0;
+
+	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
+	sctp_walk_params(param, hdr, params) {
+		__u16 length = ntohs(param.p->length);
+
+		*errp = param.p;
+		if (cnt++ > 2)
+			return false;
+		switch (param.p->type) {
+		case SCTP_PARAM_RESET_OUT_REQUEST:
+			if (length < sizeof(struct sctp_strreset_outreq) ||
+			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
+			     last != SCTP_PARAM_RESET_IN_REQUEST))
+				return false;
+			break;
+		case SCTP_PARAM_RESET_IN_REQUEST:
+			if (length < sizeof(struct sctp_strreset_inreq) ||
+			    (last && last != SCTP_PARAM_RESET_OUT_REQUEST))
+				return false;
+			break;
+		case SCTP_PARAM_RESET_RESPONSE:
+			if ((length != sizeof(struct sctp_strreset_resp) &&
+			     length != sizeof(struct sctp_strreset_resptsn)) ||
+			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
+			     last != SCTP_PARAM_RESET_OUT_REQUEST))
+				return false;
+			break;
+		case SCTP_PARAM_RESET_TSN_REQUEST:
+			if (length !=
+			    sizeof(struct sctp_strreset_tsnreq) || last)
+				return false;
+			break;
+		case SCTP_PARAM_RESET_ADD_IN_STREAMS:
+			if (length != sizeof(struct sctp_strreset_addstrm) ||
+			    (last && last != SCTP_PARAM_RESET_ADD_OUT_STREAMS))
+				return false;
+			break;
+		case SCTP_PARAM_RESET_ADD_OUT_STREAMS:
+			if (length != sizeof(struct sctp_strreset_addstrm) ||
+			    (last && last != SCTP_PARAM_RESET_ADD_IN_STREAMS))
+				return false;
+			break;
+		default:
+			return false;
+		}
+
+		last = param.p->type;
+	}
+
+	return true;
+}