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OpenCloudOS-Kernel/net/sctp/sm_make_chunk.c

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/* SCTP kernel reference 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 reference 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.
*
* The SCTP reference implementation is free software;
* you can redistribute it and/or modify it under the terms of
* the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* The SCTP reference implementation is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* ************************
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <lksctp-developers@lists.sourceforge.net>
*
* Or submit a bug report through the following website:
* http://www.sf.net/projects/lksctp
*
* Written or modified by:
* 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>
*
* Any bugs reported given to us we will try to fix... any fixes shared will
* be incorporated into the next SCTP release.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <asm/scatterlist.h>
#include <linux/crypto.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>
SCTP_STATIC
struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
__u8 type, __u8 flags, int paylen);
static sctp_cookie_param_t *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);
/* What was the inbound interface for this chunk? */
int sctp_chunk_iif(const struct sctp_chunk *chunk)
{
struct sctp_af *af;
int iif = 0;
af = sctp_get_af_specific(ipver2af(ip_hdr(chunk->skb)->version));
if (af)
iif = af->skb_iif(chunk->skb);
return iif;
}
/* 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,
__constant_htons(sizeof(struct sctp_paramhdr)),
};
static const struct sctp_paramhdr prsctp_param = {
SCTP_PARAM_FWD_TSN_SUPPORT,
__constant_htons(sizeof(struct sctp_paramhdr)),
};
/* A helper to initialize to initialize an op error inside a
* provided chunk, as most cause codes will be embedded inside an
* abort chunk.
*/
void sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
size_t paylen)
{
sctp_errhdr_t err;
__u16 len;
/* Cause code constants are now defined in network order. */
err.cause = cause_code;
len = sizeof(sctp_errhdr_t) + paylen;
err.length = htons(len);
chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err);
}
/* 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)
{
sctp_inithdr_t init;
union sctp_params addrs;
size_t chunksize;
struct sctp_chunk *retval = NULL;
int num_types, addrs_len = 0;
struct sctp_sock *sp;
sctp_supported_addrs_param_t sat;
__be16 types[2];
sctp_adaptation_ind_param_t aiparam;
/* 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.
*/
retval = NULL;
/* 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 + SCTP_SAT_LEN(num_types);
chunksize += sizeof(ecap_param);
if (sctp_prsctp_enable)
chunksize += sizeof(prsctp_param);
chunksize += sizeof(aiparam);
chunksize += vparam_len;
/* 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_chunk(asoc, SCTP_CID_INIT, 0, chunksize);
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);
sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
if (sctp_prsctp_enable)
sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
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);
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)
{
sctp_inithdr_t initack;
struct sctp_chunk *retval;
union sctp_params addrs;
int addrs_len;
sctp_cookie_param_t *cookie;
int cookie_len;
size_t chunksize;
sctp_adaptation_ind_param_t aiparam;
retval = NULL;
/* 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.
*/
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);
/* Tell peer that we'll do PR-SCTP only if peer advertised. */
if (asoc->peer.prsctp_capable)
chunksize += sizeof(prsctp_param);
chunksize += sizeof(aiparam);
/* Now allocate and fill out the chunk. */
retval = sctp_make_chunk(asoc, SCTP_CID_INIT_ACK, 0, chunksize);
if (!retval)
goto nomem_chunk;
/* Per the advice in RFC 2960 6.4, send this reply to
* the source of the INIT packet.
*/
retval->transport = chunk->transport;
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 (asoc->peer.prsctp_capable)
sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
aiparam.param_hdr.length = htons(sizeof(aiparam));
aiparam.adaptation_ind = htonl(sctp_sk(asoc->base.sk)->adaptation_ind);
sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
/* We need to remove the const qualifier at this point. */
retval->asoc = (struct sctp_association *) asoc;
/* 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)
retval->transport = chunk->transport;
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;
void *cookie;
int cookie_len;
cookie = asoc->peer.cookie;
cookie_len = asoc->peer.cookie_len;
/* Build a cookie echo chunk. */
retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len);
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_chunk(asoc, SCTP_CID_COOKIE_ACK, 0, 0);
/* 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)
retval->transport = chunk->transport;
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;
sctp_cwrhdr_t cwr;
cwr.lowest_tsn = htonl(lowest_tsn);
retval = sctp_make_chunk(asoc, SCTP_CID_ECN_CWR, 0,
sizeof(sctp_cwrhdr_t));
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;
sctp_ecnehdr_t ecne;
ecne.lowest_tsn = htonl(lowest_tsn);
retval = sctp_make_chunk(asoc, SCTP_CID_ECN_ECNE, 0,
sizeof(sctp_ecnehdr_t));
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(struct sctp_association *asoc,
const struct sctp_sndrcvinfo *sinfo,
int data_len, __u8 flags, __u16 ssn)
{
struct sctp_chunk *retval;
struct sctp_datahdr dp;
int chunk_len;
/* We assign the TSN as LATE as possible, not here when
* creating the chunk.
*/
dp.tsn = 0;
dp.stream = htons(sinfo->sinfo_stream);
dp.ppid = sinfo->sinfo_ppid;
/* Set the flags for an unordered send. */
if (sinfo->sinfo_flags & SCTP_UNORDERED) {
flags |= SCTP_DATA_UNORDERED;
dp.ssn = 0;
} else
dp.ssn = htons(ssn);
chunk_len = sizeof(dp) + data_len;
retval = sctp_make_chunk(asoc, SCTP_CID_DATA, flags, chunk_len);
if (!retval)
goto nodata;
retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
nodata:
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(const struct sctp_association *asoc)
{
struct sctp_chunk *retval;
struct sctp_sackhdr sack;
int len;
__u32 ctsn;
__u16 num_gabs, num_dup_tsns;
struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
ctsn = sctp_tsnmap_get_ctsn(map);
SCTP_DEBUG_PRINTK("sackCTSNAck sent: 0x%x.\n", ctsn);
/* How much room is needed in the chunk? */
num_gabs = sctp_tsnmap_num_gabs(map);
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_chunk(asoc, SCTP_CID_SACK, 0, len);
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,
sctp_tsnmap_get_gabs(map));
/* Add the duplicate TSN information. */
if (num_dup_tsns)
sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
sctp_tsnmap_get_dups(map));
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_chunk *retval;
sctp_shutdownhdr_t shut;
__u32 ctsn;
ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
shut.cum_tsn_ack = htonl(ctsn);
retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN, 0,
sizeof(sctp_shutdownhdr_t));
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_chunk(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0);
/* 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_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
/* 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_chunk(asoc, SCTP_CID_ABORT, flags, hint);
/* 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(sctp_errhdr_t)
+ 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,
const struct msghdr *msg,
size_t paylen)
{
struct sctp_chunk *retval;
void *payload = NULL;
int err;
retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + 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_fromiovec(payload, msg->msg_iov, 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;
}
/* 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(sctp_errhdr_t) + paylen
+ sizeof(sctp_paramhdr_t));
if (!retval)
goto end;
sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen
+ sizeof(sctp_paramhdr_t));
phdr.type = htons(chunk->chunk_hdr->type);
phdr.length = chunk->chunk_hdr->length;
sctp_addto_chunk(retval, paylen, payload);
sctp_addto_param(retval, sizeof(sctp_paramhdr_t), &phdr);
end:
return retval;
}
/* Make a HEARTBEAT chunk. */
struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
const struct sctp_transport *transport,
const void *payload, const size_t paylen)
{
struct sctp_chunk *retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT,
0, paylen);
if (!retval)
goto nodata;
/* 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, paylen, payload);
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_chunk(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
if (!retval)
goto nodata;
retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
/* RFC 2960 6.4 Multi-homed SCTP Endpoints
*
* An endpoint SHOULD transmit reply chunks (e.g., SACK,
* HEARTBEAT ACK, * etc.) to the same destination transport
* address from which it * received the DATA or control chunk
* to which it is replying.
*
* [HBACK back to where the HEARTBEAT came from.]
*/
if (chunk)
retval->transport = chunk->transport;
nodata:
return retval;
}
/* Create an Operation Error chunk with the specified space reserved.
* This routine can be used for containing multiple causes in the chunk.
*/
static struct sctp_chunk *sctp_make_op_error_space(
const struct sctp_association *asoc,
const struct sctp_chunk *chunk,
size_t size)
{
struct sctp_chunk *retval;
retval = sctp_make_chunk(asoc, SCTP_CID_ERROR, 0,
sizeof(sctp_errhdr_t) + size);
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. */
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)
{
struct sctp_chunk *retval;
retval = sctp_make_op_error_space(asoc, chunk, paylen);
if (!retval)
goto nodata;
sctp_init_cause(retval, cause_code, paylen);
sctp_addto_chunk(retval, paylen, payload);
nodata:
return retval;
}
/********************************************************************
* 2nd Level Abstractions
********************************************************************/
/* Turn an skb into a chunk.
* FIXME: Eventually move the structure directly inside the skb->cb[].
*/
struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
const struct sctp_association *asoc,
struct sock *sk)
{
struct sctp_chunk *retval;
retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);
if (!retval)
goto nodata;
if (!sk) {
SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb);
}
INIT_LIST_HEAD(&retval->list);
retval->skb = skb;
retval->asoc = (struct sctp_association *)asoc;
retval->resent = 0;
retval->has_tsn = 0;
retval->has_ssn = 0;
retval->rtt_in_progress = 0;
retval->sent_at = 0;
retval->singleton = 1;
retval->end_of_packet = 0;
retval->ecn_ce_done = 0;
retval->pdiscard = 0;
/* 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.
*/
retval->tsn_missing_report = 0;
retval->tsn_gap_acked = 0;
retval->fast_retransmit = 0;
/* If this is a fragmented message, track all fragments
* of the message (for SEND_FAILED).
*/
retval->msg = NULL;
/* Polish the bead hole. */
INIT_LIST_HEAD(&retval->transmitted_list);
INIT_LIST_HEAD(&retval->frag_list);
SCTP_DBG_OBJCNT_INC(chunk);
atomic_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.
*/
SCTP_STATIC
struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
__u8 type, __u8 flags, int paylen)
{
struct sctp_chunk *retval;
sctp_chunkhdr_t *chunk_hdr;
struct sk_buff *skb;
struct sock *sk;
/* No need to allocate LL here, as this is only a chunk. */
skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
GFP_ATOMIC);
if (!skb)
goto nodata;
/* Make room for the chunk header. */
chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
chunk_hdr->type = type;
chunk_hdr->flags = flags;
chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
sk = asoc ? asoc->base.sk : NULL;
retval = sctp_chunkify(skb, asoc, sk);
if (!retval) {
kfree_skb(skb);
goto nodata;
}
retval->chunk_hdr = chunk_hdr;
retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
/* Set the skb to the belonging sock for accounting. */
skb->sk = sk;
return retval;
nodata:
return NULL;
}
/* Release the memory occupied by a chunk. */
static void sctp_chunk_destroy(struct sctp_chunk *chunk)
{
/* Free the chunk skb data and the SCTP_chunk stub itself. */
dev_kfree_skb(chunk->skb);
SCTP_DBG_OBJCNT_DEC(chunk);
kmem_cache_free(sctp_chunk_cachep, chunk);
}
/* Possibly, free the chunk. */
void sctp_chunk_free(struct sctp_chunk *chunk)
{
BUG_ON(!list_empty(&chunk->list));
list_del_init(&chunk->transmitted_list);
/* 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)
{
atomic_inc(&ch->refcnt);
}
/* Release a reference to the chunk. */
void sctp_chunk_put(struct sctp_chunk *ch)
{
if (atomic_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)
{
void *target;
void *padding;
int chunklen = ntohs(chunk->chunk_hdr->length);
int padlen = WORD_ROUND(chunklen) - chunklen;
padding = skb_put(chunk->skb, padlen);
target = skb_put(chunk->skb, len);
memset(padding, 0, padlen);
memcpy(target, 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 to the end of a parameter. Will panic if chunk is not big
* enough.
*/
void *sctp_addto_param(struct sctp_chunk *chunk, int len, const void *data)
{
void *target;
int chunklen = ntohs(chunk->chunk_hdr->length);
target = skb_put(chunk->skb, len);
memcpy(target, data, len);
/* Adjust the chunk length field. */
chunk->chunk_hdr->length = htons(chunklen + 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 off, int len,
struct iovec *data)
{
__u8 *target;
int err = 0;
/* Make room in chunk for data. */
target = skb_put(chunk->skb, len);
/* Copy data (whole iovec) into chunk */
if ((err = memcpy_fromiovecend(target, data, off, len)))
goto out;
/* Adjust the chunk length field. */
chunk->chunk_hdr->length =
htons(ntohs(chunk->chunk_hdr->length) + len);
chunk->chunk_end = skb_tail_pointer(chunk->skb);
out:
return err;
}
/* 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_datamsg *msg;
struct sctp_chunk *lchunk;
struct sctp_stream *stream;
__u16 ssn;
__u16 sid;
if (chunk->has_ssn)
return;
/* All fragments will be on the same stream */
sid = ntohs(chunk->subh.data_hdr->stream);
stream = &chunk->asoc->ssnmap->out;
/* 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, sid);
else
ssn = sctp_ssn_peek(stream, 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;
struct sk_buff *skb;
sctp_scope_t scope;
struct sctp_af *af;
/* 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. */
af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
if (unlikely(!af))
goto fail;
af->from_skb(&asoc->c.peer_addr, skb, 1);
nodata:
return asoc;
fail:
sctp_association_free(asoc);
return NULL;
}
/* Build a cookie representing asoc.
* This INCLUDES the param header needed to put the cookie in the INIT ACK.
*/
static sctp_cookie_param_t *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)
{
sctp_cookie_param_t *retval;
struct sctp_signed_cookie *cookie;
struct scatterlist sg;
int headersize, bodysize;
unsigned int keylen;
char *key;
/* Header size is static data prior to the actual cookie, including
* any padding.
*/
headersize = sizeof(sctp_paramhdr_t) +
(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. */
do_gettimeofday(&cookie->c.expiration);
TIMEVAL_ADD(asoc->cookie_life, cookie->c.expiration);
/* 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 hash_desc desc;
/* Sign the message. */
sg.page = virt_to_page(&cookie->c);
sg.offset = (unsigned long)(&cookie->c) % PAGE_SIZE;
sg.length = bodysize;
keylen = SCTP_SECRET_SIZE;
key = (char *)ep->secret_key[ep->current_key];
desc.tfm = sctp_sk(ep->base.sk)->hmac;
desc.flags = 0;
if (crypto_hash_setkey(desc.tfm, key, keylen) ||
crypto_hash_digest(&desc, &sg, bodysize, cookie->signature))
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;
struct sctp_signed_cookie *cookie;
struct sctp_cookie *bear_cookie;
int headersize, bodysize, fixed_size;
__u8 *digest = ep->digest;
struct scatterlist sg;
unsigned int keylen, len;
char *key;
sctp_scope_t scope;
struct sk_buff *skb = chunk->skb;
struct timeval tv;
struct hash_desc desc;
/* Header size is static data prior to the actual cookie, including
* any padding.
*/
headersize = sizeof(sctp_chunkhdr_t) +
(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. */
keylen = SCTP_SECRET_SIZE;
sg.page = virt_to_page(bear_cookie);
sg.offset = (unsigned long)(bear_cookie) % PAGE_SIZE;
sg.length = bodysize;
key = (char *)ep->secret_key[ep->current_key];
desc.tfm = sctp_sk(ep->base.sk)->hmac;
desc.flags = 0;
memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
if (crypto_hash_setkey(desc.tfm, key, keylen) ||
crypto_hash_digest(&desc, &sg, bodysize, digest)) {
*error = -SCTP_IERROR_NOMEM;
goto fail;
}
if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
/* Try the previous key. */
key = (char *)ep->secret_key[ep->last_key];
memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
if (crypto_hash_setkey(desc.tfm, key, keylen) ||
crypto_hash_digest(&desc, &sg, bodysize, digest)) {
*error = -SCTP_IERROR_NOMEM;
goto fail;
}
if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
/* Yikes! Still bad signature! */
*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
* that a cookie may be considered expired, but his would only slow
* down the new association establishment instead of every packet.
*/
if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
skb_get_timestamp(skb, &tv);
else
do_gettimeofday(&tv);
if (!asoc && tv_lt(bear_cookie->expiration, tv)) {
/*
* 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.
*/
len = ntohs(chunk->chunk_hdr->length);
*errp = sctp_make_op_error_space(asoc, chunk, len);
if (*errp) {
suseconds_t usecs = (tv.tv_sec -
bear_cookie->expiration.tv_sec) * 1000000L +
tv.tv_usec - bear_cookie->expiration.tv_usec;
__be32 n = htonl(usecs);
sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
sizeof(n));
sctp_addto_chunk(*errp, sizeof(n), &n);
*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, 1,
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->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;
} __attribute__((packed));
/*
* Report a missing mandatory parameter.
*/
static int sctp_process_missing_param(const struct sctp_association *asoc,
sctp_param_t paramtype,
struct sctp_chunk *chunk,
struct sctp_chunk **errp)
{
struct __sctp_missing report;
__u16 len;
len = WORD_ROUND(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)
{
char error[] = "The following parameter had invalid length:";
size_t payload_len = WORD_ROUND(sizeof(error)) +
sizeof(sctp_paramhdr_t);
/* Create an error chunk and fill it in with our payload. */
if (!*errp)
*errp = sctp_make_op_error_space(asoc, chunk, payload_len);
if (*errp) {
sctp_init_cause(*errp, SCTP_ERROR_PROTO_VIOLATION,
sizeof(error) + sizeof(sctp_paramhdr_t));
sctp_addto_chunk(*errp, sizeof(error), error);
sctp_addto_param(*errp, sizeof(sctp_paramhdr_t), 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);
/* Make an ERROR chunk. */
if (!*errp)
*errp = sctp_make_op_error_space(asoc, chunk, len);
if (*errp) {
sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
sctp_addto_chunk(*errp, len, param.v);
}
/* Stop processing this chunk. */
return 0;
}
/* 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 SCTP chunk and discard it,
* do not process any further chunks within it.
*
* 01 - Stop processing this SCTP chunk and discard it,
* do not process any further chunks within it, and report
* the unrecognized parameter in an 'Unrecognized
* Parameter Type' (in either an ERROR or in the INIT ACK).
*
* 10 - Skip this parameter and continue processing.
*
* 11 - Skip this parameter and continue processing but
* report the unrecognized parameter in an
* 'Unrecognized Parameter Type' (in either an ERROR or in
* the INIT ACK).
*
* Return value:
* 0 - discard the chunk
* 1 - continue with the chunk
*/
static int sctp_process_unk_param(const struct sctp_association *asoc,
union sctp_params param,
struct sctp_chunk *chunk,
struct sctp_chunk **errp)
{
int retval = 1;
switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
case SCTP_PARAM_ACTION_DISCARD:
retval = 0;
break;
case SCTP_PARAM_ACTION_DISCARD_ERR:
retval = 0;
/* Make an ERROR chunk, preparing enough room for
* returning multiple unknown parameters.
*/
if (NULL == *errp)
*errp = sctp_make_op_error_space(asoc, chunk,
ntohs(chunk->chunk_hdr->length));
if (*errp) {
sctp_init_cause(*errp, SCTP_ERROR_UNKNOWN_PARAM,
WORD_ROUND(ntohs(param.p->length)));
sctp_addto_chunk(*errp,
WORD_ROUND(ntohs(param.p->length)),
param.v);
}
break;
case SCTP_PARAM_ACTION_SKIP:
break;
case SCTP_PARAM_ACTION_SKIP_ERR:
/* Make an ERROR chunk, preparing enough room for
* returning multiple unknown parameters.
*/
if (NULL == *errp)
*errp = sctp_make_op_error_space(asoc, chunk,
ntohs(chunk->chunk_hdr->length));
if (*errp) {
sctp_init_cause(*errp, SCTP_ERROR_UNKNOWN_PARAM,
WORD_ROUND(ntohs(param.p->length)));
sctp_addto_chunk(*errp,
WORD_ROUND(ntohs(param.p->length)),
param.v);
} else {
/* 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 = 0;
}
break;
default:
break;
}
return retval;
}
/* Find unrecognized parameters in the chunk.
* Return values:
* 0 - discard the chunk
* 1 - continue with the chunk
*/
static int sctp_verify_param(const struct sctp_association *asoc,
union sctp_params param,
sctp_cid_t cid,
struct sctp_chunk *chunk,
struct sctp_chunk **err_chunk)
{
int retval = 1;
/* 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_HOST_NAME_ADDRESS:
/* Tell the peer, we won't support this param. */
return sctp_process_hn_param(asoc, param, chunk, err_chunk);
case SCTP_PARAM_FWD_TSN_SUPPORT:
if (sctp_prsctp_enable)
break;
/* Fall Through */
default:
SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n",
ntohs(param.p->type), cid);
return sctp_process_unk_param(asoc, param, chunk, err_chunk);
break;
}
return retval;
}
/* Verify the INIT packet before we process it. */
int sctp_verify_init(const struct sctp_association *asoc,
sctp_cid_t cid,
sctp_init_chunk_t *peer_init,
struct sctp_chunk *chunk,
struct sctp_chunk **errp)
{
union sctp_params param;
int has_cookie = 0;
/* Verify stream values are non-zero. */
if ((0 == peer_init->init_hdr.num_outbound_streams) ||
(0 == peer_init->init_hdr.num_inbound_streams) ||
(0 == peer_init->init_hdr.init_tag) ||
(SCTP_DEFAULT_MINWINDOW > ntohl(peer_init->init_hdr.a_rwnd))) {
sctp_process_inv_mandatory(asoc, chunk, errp);
return 0;
}
/* Check for missing mandatory parameters. */
sctp_walk_params(param, peer_init, init_hdr.params) {
if (SCTP_PARAM_STATE_COOKIE == param.p->type)
has_cookie = 1;
} /* for (loop through all parameters) */
/* 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) {
sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
return 0;
}
/* The only missing mandatory param possible today is
* the state cookie for an INIT-ACK chunk.
*/
if ((SCTP_CID_INIT_ACK == cid) && !has_cookie) {
sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
chunk, errp);
return 0;
}
/* Find unrecognized parameters. */
sctp_walk_params(param, peer_init, init_hdr.params) {
if (!sctp_verify_param(asoc, param, cid, chunk, errp)) {
if (SCTP_PARAM_HOST_NAME_ADDRESS == param.p->type)
return 0;
else
return 1;
}
} /* 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, sctp_cid_t cid,
const union sctp_addr *peer_addr,
sctp_init_chunk_t *peer_init, gfp_t gfp)
{
union sctp_params param;
struct sctp_transport *transport;
struct list_head *pos, *temp;
char *cookie;
/* 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 a better choice than any of the embedded addresses.
*/
if (peer_addr) {
if(!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
goto nomem;
}
/* Process the initialization parameters. */
sctp_walk_params(param, peer_init, init_hdr.params) {
if (!sctp_process_param(asoc, param, peer_addr, gfp))
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);
/* 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;
/* Copy cookie in case we need to resend COOKIE-ECHO. */
cookie = asoc->peer.cookie;
if (cookie) {
asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
if (!asoc->peer.cookie)
goto clean_up;
}
/* 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(pos, &asoc->peer.transport_addr_list) {
transport = list_entry(pos, struct sctp_transport, transports);
transport->ssthresh = asoc->peer.i.a_rwnd;
}
/* Set up the TSN tracking pieces. */
sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_SIZE,
asoc->peer.i.initial_tsn);
/* 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.
*/
/* Allocate storage for the negotiated streams if it is not a temporary
* association.
*/
if (!asoc->temp) {
int error;
asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
asoc->c.sinit_num_ostreams, gfp);
if (!asoc->ssnmap)
goto clean_up;
error = sctp_assoc_set_id(asoc, gfp);
if (error)
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);
list_del_init(pos);
sctp_transport_free(transport);
}
asoc->peer.transport_count = 0;
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)
{
union sctp_addr addr;
int i;
__u16 sat;
int retval = 1;
sctp_scope_t scope;
time_t stale;
struct sctp_af *af;
/* 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;
/* Fall through. */
case SCTP_PARAM_IPV4_ADDRESS:
af = sctp_get_af_specific(param_type2af(param.p->type));
af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
scope = sctp_scope(peer_addr);
if (sctp_in_scope(&addr, scope))
if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
return 0;
break;
case SCTP_PARAM_COOKIE_PRESERVATIVE:
if (!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.tv_sec += stale / 1000;
asoc->cookie_life.tv_usec += (stale % 1000) * 1000;
break;
case SCTP_PARAM_HOST_NAME_ADDRESS:
SCTP_DEBUG_PRINTK("unimplemented SCTP_HOST_NAME_ADDRESS\n");
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;
/* Cycle through address types; avoid divide by 0. */
sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
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:
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(sctp_paramhdr_t);
asoc->peer.cookie = param.cookie->body;
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:
asoc->peer.ecn_capable = 1;
break;
case SCTP_PARAM_ADAPTATION_LAYER_IND:
asoc->peer.adaptation_ind = param.aind->adaptation_ind;
break;
case SCTP_PARAM_FWD_TSN_SUPPORT:
if (sctp_prsctp_enable) {
asoc->peer.prsctp_capable = 1;
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.
*/
SCTP_DEBUG_PRINTK("Ignoring param: %d for association %p.\n",
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)
{
sctp_addiphdr_t 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_chunk(asoc, SCTP_CID_ASCONF, 0, length);
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)
{
sctp_addip_param_t param;
struct sctp_chunk *retval;
union sctp_addr_param addr_param;
union sctp_addr *addr;
void *addr_buf;
struct sctp_af *af;
int paramlen = sizeof(param);
int addr_param_len = 0;
int totallen = 0;
int i;
/* Get total length of all the address parameters. */
addr_buf = addrs;
for (i = 0; i < addrcnt; i++) {
addr = (union sctp_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;
}
/* 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 = (union sctp_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 = i;
sctp_addto_chunk(retval, paramlen, &param);
sctp_addto_chunk(retval, addr_param_len, &addr_param);
addr_buf += af->sockaddr_len;
}
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)
{
sctp_addip_param_t param;
struct sctp_chunk *retval;
int len = sizeof(param);
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;
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)
{
sctp_addiphdr_t asconf;
struct sctp_chunk *retval;
int length = sizeof(asconf) + vparam_len;
/* Create the chunk. */
retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF_ACK, 0, length);
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, sctp_addip_param_t *asconf_param)
{
sctp_addip_param_t ack_param;
sctp_errhdr_t 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,
sctp_addip_param_t *asconf_param)
{
struct sctp_transport *peer;
struct sctp_af *af;
union sctp_addr addr;
struct list_head *pos;
union sctp_addr_param *addr_param;
addr_param = (union sctp_addr_param *)
((void *)asconf_param + sizeof(sctp_addip_param_t));
af = sctp_get_af_specific(param_type2af(addr_param->v4.param_hdr.type));
if (unlikely(!af))
return SCTP_ERROR_INV_PARAM;
af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
switch (asconf_param->param_hdr.type) {
case SCTP_PARAM_ADD_IP:
/* 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. */
if (!mod_timer(&peer->hb_timer, sctp_transport_timeout(peer)))
sctp_transport_hold(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'.
*/
pos = asoc->peer.transport_addr_list.next;
if (pos->next == &asoc->peer.transport_addr_list)
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(sctp_source(asconf), &addr))
return SCTP_ERROR_DEL_SRC_IP;
sctp_assoc_del_peer(asoc, &addr);
break;
case SCTP_PARAM_SET_PRIMARY:
peer = sctp_assoc_lookup_paddr(asoc, &addr);
if (!peer)
return SCTP_ERROR_INV_PARAM;
sctp_assoc_set_primary(asoc, peer);
break;
default:
return SCTP_ERROR_INV_PARAM;
break;
}
return SCTP_ERROR_NO_ERROR;
}
/* Verify the ASCONF packet before we process it. */
int sctp_verify_asconf(const struct sctp_association *asoc,
struct sctp_paramhdr *param_hdr, void *chunk_end,
struct sctp_paramhdr **errp) {
sctp_addip_param_t *asconf_param;
union sctp_params param;
int length, plen;
param.v = (sctp_paramhdr_t *) param_hdr;
while (param.v <= chunk_end - sizeof(sctp_paramhdr_t)) {
length = ntohs(param.p->length);
*errp = param.p;
if (param.v > chunk_end - length ||
length < sizeof(sctp_paramhdr_t))
return 0;
switch (param.p->type) {
case SCTP_PARAM_ADD_IP:
case SCTP_PARAM_DEL_IP:
case SCTP_PARAM_SET_PRIMARY:
asconf_param = (sctp_addip_param_t *)param.v;
plen = ntohs(asconf_param->param_hdr.length);
if (plen < sizeof(sctp_addip_param_t) +
sizeof(sctp_paramhdr_t))
return 0;
break;
case SCTP_PARAM_SUCCESS_REPORT:
case SCTP_PARAM_ADAPTATION_LAYER_IND:
if (length != sizeof(sctp_addip_param_t))
return 0;
break;
default:
break;
}
param.v += WORD_ROUND(length);
}
if (param.v != chunk_end)
return 0;
return 1;
}
/* 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)
{
sctp_addiphdr_t *hdr;
union sctp_addr_param *addr_param;
sctp_addip_param_t *asconf_param;
struct sctp_chunk *asconf_ack;
__be16 err_code;
int length = 0;
int chunk_len = asconf->skb->len;
__u32 serial;
int all_param_pass = 1;
hdr = (sctp_addiphdr_t *)asconf->skb->data;
serial = ntohl(hdr->serial);
/* Skip the addiphdr and store a pointer to address parameter. */
length = sizeof(sctp_addiphdr_t);
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 paramter.
*/
length = ntohs(addr_param->v4.param_hdr.length);
asconf_param = (sctp_addip_param_t *)((void *)addr_param + 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 twice of ASCONF
* paramters.
*/
asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 2);
if (!asconf_ack)
goto done;
/* Process the TLVs contained within the ASCONF chunk. */
while (chunk_len > 0) {
err_code = sctp_process_asconf_param(asoc, asconf,
asconf_param);
/* 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 (SCTP_ERROR_NO_ERROR != err_code)
all_param_pass = 0;
if (!all_param_pass)
sctp_add_asconf_response(asconf_ack,
asconf_param->crr_id, err_code,
asconf_param);
/* 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 (SCTP_ERROR_RSRC_LOW == err_code)
goto done;
/* Move to the next ASCONF param. */
length = ntohs(asconf_param->param_hdr.length);
asconf_param = (sctp_addip_param_t *)((void *)asconf_param +
length);
chunk_len -= length;
}
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) {
if (asoc->addip_last_asconf_ack)
sctp_chunk_free(asoc->addip_last_asconf_ack);
sctp_chunk_hold(asconf_ack);
asoc->addip_last_asconf_ack = asconf_ack;
}
return asconf_ack;
}
/* Process a asconf parameter that is successfully acked. */
static int sctp_asconf_param_success(struct sctp_association *asoc,
sctp_addip_param_t *asconf_param)
{
struct sctp_af *af;
union sctp_addr addr;
struct sctp_bind_addr *bp = &asoc->base.bind_addr;
union sctp_addr_param *addr_param;
struct list_head *pos;
struct sctp_transport *transport;
struct sctp_sockaddr_entry *saddr;
int retval = 0;
addr_param = (union sctp_addr_param *)
((void *)asconf_param + sizeof(sctp_addip_param_t));
/* We have checked the packet before, so we do not check again. */
af = sctp_get_af_specific(param_type2af(addr_param->v4.param_hdr.type));
af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
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.
*/
list_for_each_entry(saddr, &bp->address_list, list) {
if (sctp_cmp_addr_exact(&saddr->a, &addr))
saddr->use_as_src = 1;
}
break;
case SCTP_PARAM_DEL_IP:
retval = sctp_del_bind_addr(bp, &addr, call_rcu_bh);
list_for_each(pos, &asoc->peer.transport_addr_list) {
transport = list_entry(pos, struct sctp_transport,
transports);
dst_release(transport->dst);
sctp_transport_route(transport, NULL,
sctp_sk(asoc->base.sk));
}
break;
default:
break;
}
return retval;
}
/* 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,
sctp_addip_param_t *asconf_param,
int no_err)
{
sctp_addip_param_t *asconf_ack_param;
sctp_errhdr_t *err_param;
int length;
int asconf_ack_len = asconf_ack->skb->len;
__be16 err_code;
if (no_err)
err_code = SCTP_ERROR_NO_ERROR;
else
err_code = SCTP_ERROR_REQ_REFUSED;
/* Skip the addiphdr from the asconf_ack chunk and store a pointer to
* the first asconf_ack parameter.
*/
length = sizeof(sctp_addiphdr_t);
asconf_ack_param = (sctp_addip_param_t *)(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(sctp_addip_param_t);
err_param = (sctp_errhdr_t *)
((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 = (sctp_addip_param_t *)
((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;
union sctp_addr_param *addr_param;
sctp_addip_param_t *asconf_param;
int length = 0;
int asconf_len = asconf->skb->len;
int all_param_pass = 0;
int no_err = 1;
int retval = 0;
__be16 err_code = SCTP_ERROR_NO_ERROR;
/* Skip the chunkhdr and addiphdr from the last asconf sent and store
* a pointer to address parameter.
*/
length = sizeof(sctp_addip_chunk_t);
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 paramter.
*/
length = ntohs(addr_param->v4.param_hdr.length);
asconf_param = (sctp_addip_param_t *)((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(sctp_addiphdr_t))
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:
retval = sctp_asconf_param_success(asoc, asconf_param);
break;
case SCTP_ERROR_RSRC_LOW:
retval = 1;
break;
case SCTP_ERROR_INV_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 = (sctp_addip_param_t *)((void *)asconf_param +
length);
asconf_len -= length;
}
/* Free the cached last sent asconf chunk. */
sctp_chunk_free(asconf);
asoc->addip_last_asconf = NULL;
/* Send the next asconf chunk from the addip chunk queue. */
if (!list_empty(&asoc->addip_chunk_list)) {
struct list_head *entry = asoc->addip_chunk_list.next;
asconf = list_entry(entry, struct sctp_chunk, list);
list_del_init(entry);
/* Hold the chunk until an ASCONF_ACK is received. */
sctp_chunk_hold(asconf);
if (sctp_primitive_ASCONF(asoc, asconf))
sctp_chunk_free(asconf);
else
asoc->addip_last_asconf = asconf;
}
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_chunk *ftsn_chunk;
struct sctp_fwdtsn_hdr ftsn_hdr;
struct sctp_fwdtsn_skip skip;
size_t hint;
int i;
hint = (nstreams + 1) * sizeof(__u32);
retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);
if (!retval)
return NULL;
ftsn_chunk = (struct sctp_fwdtsn_chunk *)retval->subh.fwdtsn_hdr;
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;
}
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