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linux/net/sctp/sm_make_chunk.c
Marcelo Ricardo Leitner ba6f5e33bd sctp: avoid refreshing heartbeat timer too often 
Currently on high rate SCTP streams the heartbeat timer refresh can
consume quite a lot of resources as timer updates are costly and it
contains a random factor, which a) is also costly and b) invalidates
mod_timer() optimization for not editing a timer to the same value.
It may even cause the timer to be slightly advanced, for no good reason.

As suggested by David Laight this patch now removes this timer update
from hot path by leaving the timer on and re-evaluating upon its
expiration if the heartbeat is still needed or not, similarly to what is
done for TCP. If it's not needed anymore the timer is re-scheduled to
the new timeout, considering the time already elapsed.

For this, we now record the last tx timestamp per transport, updated in
the same spots as hb timer was restarted on tx. Also split up
sctp_transport_reset_timers into sctp_transport_reset_t3_rtx and
sctp_transport_reset_hb_timer, so we can re-arm T3 without re-arming the
heartbeat one.

On loopback with MTU of 65535 and data chunks with 1636, so that we
have a considerable amount of chunks without stressing system calls,
netperf -t SCTP_STREAM -l 30, perf looked like this before:

Samples: 103K of event 'cpu-clock', Event count (approx.): 25833000000
  Overhead  Command  Shared Object      Symbol
+    6,15%  netperf  [kernel.vmlinux]   [k] copy_user_enhanced_fast_string
-    5,43%  netperf  [kernel.vmlinux]   [k] _raw_write_unlock_irqrestore
   - _raw_write_unlock_irqrestore
      - 96,54% _raw_spin_unlock_irqrestore
         - 36,14% mod_timer
            + 97,24% sctp_transport_reset_timers
            + 2,76% sctp_do_sm
         + 33,65% __wake_up_sync_key
         + 28,77% sctp_ulpq_tail_event
         + 1,40% del_timer
      - 1,84% mod_timer
         + 99,03% sctp_transport_reset_timers
         + 0,97% sctp_do_sm
      + 1,50% sctp_ulpq_tail_event

And after this patch, now with netperf -l 60:

Samples: 230K of event 'cpu-clock', Event count (approx.): 57707250000
  Overhead  Command  Shared Object      Symbol
+    5,65%  netperf  [kernel.vmlinux]   [k] memcpy_erms
+    5,59%  netperf  [kernel.vmlinux]   [k] copy_user_enhanced_fast_string
-    5,05%  netperf  [kernel.vmlinux]   [k] _raw_spin_unlock_irqrestore
   - _raw_spin_unlock_irqrestore
      + 49,89% __wake_up_sync_key
      + 45,68% sctp_ulpq_tail_event
      - 2,85% mod_timer
         + 76,51% sctp_transport_reset_t3_rtx
         + 23,49% sctp_do_sm
      + 1,55% del_timer
+    2,50%  netperf  [sctp]             [k] sctp_datamsg_from_user
+    2,26%  netperf  [sctp]             [k] sctp_sendmsg

Throughput-wise, from 6800mbps without the patch to 7050mbps with it,
~3.7%.

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-10 22:22:34 -04:00

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/* 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.
*
* This SCTP implementation is free software;
* you can redistribute it and/or modify it under the terms of
* the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This SCTP implementation is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* ************************
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, see
* <http://www.gnu.org/licenses/>.
*
* 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 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);
static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
const void *data);
static void *sctp_addto_chunk_fixed(struct sctp_chunk *, int len,
const void *data);
/* Control chunk destructor */
static void sctp_control_release_owner(struct sk_buff *skb)
{
/*TODO: do memory release */
}
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.
*/
skb->sk = asoc ? asoc->base.sk : NULL;
skb->destructor = sctp_control_release_owner;
}
/* 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,
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.
*/
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);
}
/* A helper to initialize an op error inside a
* provided chunk, as most cause codes will be embedded inside an
* abort chunk. Differs from sctp_init_cause in that it won't oops
* if there isn't enough space in the op error chunk
*/
static int sctp_init_cause_fixed(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);
if (skb_tailroom(chunk->skb) < len)
return -ENOSPC;
chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
sizeof(sctp_errhdr_t),
&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 net *net = sock_net(asoc->base.sk);
struct sctp_endpoint *ep = asoc->ep;
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;
sctp_supported_ext_param_t ext_param;
int num_ext = 0;
__u8 extensions[3];
sctp_paramhdr_t *auth_chunks = NULL,
*auth_hmacs = NULL;
/* 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;
chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types));
chunksize += sizeof(ecap_param);
if (net->sctp.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 (net->sctp.addip_enable) {
extensions[num_ext] = SCTP_CID_ASCONF;
extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
num_ext += 2;
}
if (sp->adaptation_ind)
chunksize += sizeof(aiparam);
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 = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
if (auth_hmacs->length)
chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
else
auth_hmacs = NULL;
/* Add CHUNKS parameter length */
auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
if (auth_chunks->length)
chunksize += WORD_ROUND(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 += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
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);
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(sctp_supported_ext_param_t) + num_ext);
sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
&ext_param);
sctp_addto_param(retval, num_ext, extensions);
}
if (net->sctp.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)
{
sctp_inithdr_t initack;
struct sctp_chunk *retval;
union sctp_params addrs;
struct sctp_sock *sp;
int addrs_len;
sctp_cookie_param_t *cookie;
int cookie_len;
size_t chunksize;
sctp_adaptation_ind_param_t aiparam;
sctp_supported_ext_param_t ext_param;
int num_ext = 0;
__u8 extensions[3];
sctp_paramhdr_t *auth_chunks = NULL,
*auth_hmacs = NULL,
*auth_random = NULL;
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.
*/
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 (sp->adaptation_ind)
chunksize += sizeof(aiparam);
if (asoc->peer.auth_capable) {
auth_random = (sctp_paramhdr_t *)asoc->c.auth_random;
chunksize += ntohs(auth_random->length);
auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
if (auth_hmacs->length)
chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
else
auth_hmacs = NULL;
auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
if (auth_chunks->length)
chunksize += WORD_ROUND(ntohs(auth_chunks->length));
else
auth_chunks = NULL;
extensions[num_ext] = SCTP_CID_AUTH;
num_ext += 1;
}
if (num_ext)
chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
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.]
*/
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 (num_ext) {
ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
ext_param.param_hdr.length =
htons(sizeof(sctp_supported_ext_param_t) + num_ext);
sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
&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;
void *cookie;
int cookie_len;
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)
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_control(asoc, SCTP_CID_ECN_CWR, 0,
sizeof(sctp_cwrhdr_t), 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;
sctp_ecnehdr_t ecne;
ecne.lowest_tsn = htonl(lowest_tsn);
retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0,
sizeof(sctp_ecnehdr_t), 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(struct sctp_association *asoc,
const struct sctp_sndrcvinfo *sinfo,
int data_len, __u8 flags, __u16 ssn,
gfp_t gfp)
{
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_data(asoc, flags, chunk_len, gfp);
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_association *aptr = (struct sctp_association *)asoc;
struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
struct sctp_transport *trans;
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) {
aptr->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 (++aptr->peer.sack_generation == 0) {
list_for_each_entry(trans, &asoc->peer.transport_addr_list,
transports)
trans->sack_generation = 0;
aptr->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_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_control(asoc, SCTP_CID_SHUTDOWN, 0,
sizeof(sctp_shutdownhdr_t), 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(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,
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_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)
{
void *target;
int chunklen = ntohs(chunk->chunk_hdr->length);
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(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;
}
struct sctp_chunk *sctp_make_violation_paramlen(
const struct sctp_association *asoc,
const struct sctp_chunk *chunk,
struct sctp_paramhdr *param)
{
struct sctp_chunk *retval;
static const char error[] = "The following parameter had invalid length:";
size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
sizeof(sctp_paramhdr_t);
retval = sctp_make_abort(asoc, chunk, payload_len);
if (!retval)
goto nodata;
sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
sizeof(error) + sizeof(sctp_paramhdr_t));
sctp_addto_chunk(retval, sizeof(error), error);
sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);
nodata:
return retval;
}
struct sctp_chunk *sctp_make_violation_max_retrans(
const struct sctp_association *asoc,
const struct sctp_chunk *chunk)
{
struct sctp_chunk *retval;
static const char error[] = "Association exceeded its max_retans count";
size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t);
retval = sctp_make_abort(asoc, chunk, payload_len);
if (!retval)
goto nodata;
sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, sizeof(error));
sctp_addto_chunk(retval, sizeof(error), error);
nodata:
return retval;
}
/* Make a HEARTBEAT chunk. */
struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
const struct sctp_transport *transport)
{
struct sctp_chunk *retval;
sctp_sender_hb_info_t hbinfo;
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(sctp_sender_hb_info_t));
hbinfo.daddr = transport->ipaddr;
hbinfo.sent_at = jiffies;
hbinfo.hb_nonce = transport->hb_nonce;
/* Cast away the 'const', as this is just telling the chunk
* what transport it belongs to.
*/
retval->transport = (struct sctp_transport *) transport;
retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
&hbinfo);
nodata:
return retval;
}
struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
const struct sctp_chunk *chunk,
const void *payload, const size_t paylen)
{
struct sctp_chunk *retval;
retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen,
GFP_ATOMIC);
if (!retval)
goto nodata;
retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
/* RFC 2960 6.4 Multi-homed SCTP Endpoints
*
* An endpoint SHOULD transmit reply chunks (e.g., SACK,
* HEARTBEAT ACK, * etc.) to the same destination transport
* address from which it * received the DATA or control chunk
* to which it is replying.
*
* [HBACK back to where the HEARTBEAT came from.]
*/
if (chunk)
retval->transport = chunk->transport;
nodata:
return retval;
}
/* Create an Operation Error chunk with the specified space reserved.
* This routine can be used for containing multiple causes in the chunk.
*/
static struct sctp_chunk *sctp_make_op_error_space(
const struct sctp_association *asoc,
const struct sctp_chunk *chunk,
size_t size)
{
struct sctp_chunk *retval;
retval = sctp_make_control(asoc, SCTP_CID_ERROR, 0,
sizeof(sctp_errhdr_t) + 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, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
* This is a helper function to allocate an error chunk for
* for those invalid parameter codes in which we may not want
* to report all the errors, if the incoming chunk is large
*/
static inline struct sctp_chunk *sctp_make_op_error_fixed(
const struct sctp_association *asoc,
const struct sctp_chunk *chunk)
{
size_t size = asoc ? asoc->pathmtu : 0;
if (!size)
size = SCTP_DEFAULT_MAXSEGMENT;
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)
{
struct sctp_chunk *retval;
struct sctp_hmac *hmac_desc;
struct sctp_authhdr auth_hdr;
__u8 *hmac;
/* 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(sctp_authhdr_t),
GFP_ATOMIC);
if (!retval)
return NULL;
auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
auth_hdr.shkey_id = htons(asoc->active_key_id);
retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
&auth_hdr);
hmac = skb_put(retval->skb, hmac_desc->hmac_len);
memset(hmac, 0, 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);
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.
*/
static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
__u8 type, __u8 flags, int paylen,
gfp_t gfp)
{
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);
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, gfp);
if (!retval) {
kfree_skb(skb);
goto nodata;
}
retval->chunk_hdr = chunk_hdr;
retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
/* 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);
}
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)
{
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 chunk. Returns NULL if there isn't sufficient
* space in the chunk
*/
static void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
int len, const void *data)
{
if (skb_tailroom(chunk->skb) >= len)
return sctp_addto_chunk(chunk, len, data);
else
return NULL;
}
/* 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;
ssize_t copied;
/* Make room in chunk for data. */
target = skb_put(chunk->skb, len);
/* Copy data (whole iovec) into chunk */
copied = copy_from_iter(target, len, from);
if (copied != len)
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_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;
int headersize, bodysize;
/* 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. */
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) {
SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
int err;
/* Sign the message. */
desc->tfm = sctp_sk(ep->base.sk)->hmac;
desc->flags = 0;
err = crypto_shash_setkey(desc->tfm, ep->secret_key,
sizeof(ep->secret_key)) ?:
crypto_shash_digest(desc, (u8 *)&cookie->c, bodysize,
cookie->signature);
shash_desc_zero(desc);
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;
struct sctp_signed_cookie *cookie;
struct sctp_cookie *bear_cookie;
int headersize, bodysize, fixed_size;
__u8 *digest = ep->digest;
unsigned int len;
sctp_scope_t scope;
struct sk_buff *skb = chunk->skb;
ktime_t kt;
/* 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. */
{
SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
int err;
desc->tfm = sctp_sk(ep->base.sk)->hmac;
desc->flags = 0;
err = crypto_shash_setkey(desc->tfm, ep->secret_key,
sizeof(ep->secret_key)) ?:
crypto_shash_digest(desc, (u8 *)bear_cookie, bodysize,
digest);
shash_desc_zero(desc);
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
* 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))
kt = skb_get_ktime(skb);
else
kt = ktime_get_real();
if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
/*
* 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 = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
__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,
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->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,
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)
{
/* 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_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;
}
static int sctp_verify_ext_param(struct net *net, union sctp_params param)
{
__u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
int have_auth = 0;
int have_asconf = 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 (net->sctp.addip_enable && !have_auth && have_asconf)
return 0;
return 1;
}
static void sctp_process_ext_param(struct sctp_association *asoc,
union sctp_params param)
{
struct net *net = sock_net(asoc->base.sk);
__u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
int i;
for (i = 0; i < num_ext; i++) {
switch (param.ext->chunks[i]) {
case SCTP_CID_FWD_TSN:
if (net->sctp.prsctp_enable && !asoc->peer.prsctp_capable)
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 (net->sctp.addip_enable)
asoc->peer.asconf_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 sctp_ierror_t 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;
/* Fall through */
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_fixed(asoc, chunk);
if (*errp) {
if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
WORD_ROUND(ntohs(param.p->length))))
sctp_addto_chunk_fixed(*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 = SCTP_IERROR_NOMEM;
}
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 sctp_ierror_t sctp_verify_param(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
union sctp_params param,
sctp_cid_t 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, param))
return SCTP_IERROR_ABORT;
break;
case SCTP_PARAM_SET_PRIMARY:
if (net->sctp.addip_enable)
break;
goto fallthrough;
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 (net->sctp.prsctp_enable)
break;
goto fallthrough;
case SCTP_PARAM_RANDOM:
if (!ep->auth_enable)
goto fallthrough;
/* 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(sctp_paramhdr_t)) {
sctp_process_inv_paramlength(asoc, param.p,
chunk, err_chunk);
retval = SCTP_IERROR_ABORT;
}
break;
case SCTP_PARAM_CHUNKS:
if (!ep->auth_enable)
goto fallthrough;
/* 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 fallthrough;
hmacs = (struct sctp_hmac_algo_param *)param.p;
n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 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;
fallthrough:
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, sctp_cid_t cid,
sctp_init_chunk_t *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,
sctp_init_chunk_t *peer_init, gfp_t gfp)
{
struct net *net = sock_net(asoc->base.sk);
union sctp_params param;
struct sctp_transport *transport;
struct list_head *pos, *temp;
struct sctp_af *af;
union sctp_addr addr;
char *cookie;
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 a better choice than any of the embedded addresses.
*/
if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
goto nomem;
if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
src_match = 1;
/* Process the initialization parameters. */
sctp_walk_params(param, peer_init, init_hdr.params) {
if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
af = sctp_get_af_specific(param_type2af(param.p->type));
af->from_addr_param(&addr, param.addr,
chunk->sctp_hdr->source, 0);
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 (!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);
/* 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_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.
*/
/* 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);
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 net *net = sock_net(asoc->base.sk);
union sctp_addr addr;
int i;
__u16 sat;
int retval = 1;
sctp_scope_t scope;
u32 stale;
struct sctp_af *af;
union sctp_addr_param *addr_param;
struct sctp_transport *t;
struct sctp_endpoint *ep = asoc->ep;
/* 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));
af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
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(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:
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(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 = ntohl(param.aind->adaptation_ind);
break;
case SCTP_PARAM_SET_PRIMARY:
if (!net->sctp.addip_enable)
goto fall_through;
addr_param = param.v + sizeof(sctp_addip_param_t);
af = sctp_get_af_specific(param_type2af(addr_param->p.type));
if (af == NULL)
break;
af->from_addr_param(&addr, addr_param,
htons(asoc->peer.port), 0);
/* if the address is invalid, we can't process it.
* XXX: see spec for what to do.
*/
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 (net->sctp.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 */
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 */
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;
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)
{
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_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)
{
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;
int del_pickup = 0;
/* 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 = 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 = 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)
{
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_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, 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;
union sctp_addr_param *addr_param;
addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
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;
af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
/* 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));
/* 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.v4, sctp_source(asconf), sizeof(addr));
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)
{
sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) chunk->chunk_hdr;
union sctp_params param;
bool addr_param_seen = false;
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(sctp_ipv4addr_param_t))
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(sctp_ipv6addr_param_t))
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(sctp_addip_param_t) +
sizeof(sctp_paramhdr_t))
return false;
break;
case SCTP_PARAM_SUCCESS_REPORT:
case SCTP_PARAM_ADAPTATION_LAYER_IND:
if (length != sizeof(sctp_addip_param_t))
return false;
break;
default:
/* This is unkown to us, reject! */
return false;
}
}
/* Remaining sanity checks. */
if (addr_param_needed && !addr_param_seen)
return false;
if (!addr_param_needed && addr_param_seen)
return false;
if (param.v != chunk->chunk_end)
return false;
return true;
}
/* Process an incoming ASCONF chunk with the next expected serial no. and
* return an ASCONF_ACK chunk to be sent in response.
*/
struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
struct sctp_chunk *asconf)
{
sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) asconf->chunk_hdr;
bool all_param_pass = true;
union sctp_params param;
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;
__u32 serial;
chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
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 parameter.
*/
length = ntohs(addr_param->p.length);
asconf_param = (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 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,
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 sctp_transport *transport;
struct sctp_sockaddr_entry *saddr;
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->p.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.
*/
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) {
dst_release(transport->dst);
transport->dst = NULL;
}
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) {
dst_release(transport->dst);
transport->dst = NULL;
}
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,
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;
__be16 err_code;
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(sctp_chunkhdr_t);
/* 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 = (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;
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 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(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:
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;
}
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