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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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;
 
     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;
 }
 
 struct sctp_chunk *sctp_make_new_encap_port(const struct sctp_association *asoc,
                         const struct sctp_chunk *chunk)
 {
     struct sctp_new_encap_port_hdr nep;
     struct sctp_chunk *retval;
 
     retval = sctp_make_abort(asoc, chunk,
                  sizeof(struct sctp_errhdr) + sizeof(nep));
     if (!retval)
         goto nodata;
 
     sctp_init_cause(retval, SCTP_ERROR_NEW_ENCAP_PORT, sizeof(nep));
     nep.cur_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
     nep.new_port = chunk->transport->encap_port;
     sctp_addto_chunk(retval, sizeof(nep), &nep);
 
 nodata:
     return retval;
 }
 
 /* Make a HEARTBEAT chunk.  */
 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
                        const struct sctp_transport *transport,
                        __u32 probe_size)
 {
     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;
     hbinfo.probe_size = probe_size;
 
     /* 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);
     retval->pmtu_probe = !!probe_size;
 
 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;
 }
 
 /* RFC4820 3. Padding Chunk (PAD)
  *  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 = 0x84   |   Flags=0     |             Length            |
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  * |                                                               |
  * \                         Padding Data                          /
  * /                                                               \
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  */
 struct sctp_chunk *sctp_make_pad(const struct sctp_association *asoc, int len)
 {
     struct sctp_chunk *retval;
 
     retval = sctp_make_control(asoc, SCTP_CID_PAD, 0, len, GFP_ATOMIC);
     if (!retval)
         return NULL;
 
     skb_put_zero(retval->skb, len);
     retval->chunk_hdr->length = htons(ntohs(retval->chunk_hdr->length) + len);
     retval->chunk_end = skb_tail_pointer(retval->skb);
 
     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.
      */
     asoc->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
     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 unknown 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;
 }