blob: 3ee27b7704ffb95430541507e83973e9207f9672 [file] [log] [blame]
/* SCTP kernel implementation
* (C) Copyright IBM Corp. 2001, 2004
* Copyright (c) 1999-2000 Cisco, Inc.
* Copyright (c) 1999-2001 Motorola, Inc.
* Copyright (c) 2001-2002 Intel Corp.
* Copyright (c) 2002 Nokia Corp.
*
* This is part of the SCTP Linux Kernel Implementation.
*
* These are the state functions for the state machine.
*
* This SCTP implementation is free software;
* you can redistribute it and/or modify it under the terms of
* the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This SCTP implementation is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* ************************
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, 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>
* Mathew Kotowsky <kotowsky@sctp.org>
* Sridhar Samudrala <samudrala@us.ibm.com>
* Jon Grimm <jgrimm@us.ibm.com>
* Hui Huang <hui.huang@nokia.com>
* Dajiang Zhang <dajiang.zhang@nokia.com>
* Daisy Chang <daisyc@us.ibm.com>
* Ardelle Fan <ardelle.fan@intel.com>
* Ryan Layer <rmlayer@us.ibm.com>
* Kevin Gao <kevin.gao@intel.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/inet_ecn.h>
#include <linux/skbuff.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
#include <net/sctp/structs.h>
static struct sctp_packet *sctp_abort_pkt_new(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
struct sctp_chunk *chunk,
const void *payload,
size_t paylen);
static int sctp_eat_data(const struct sctp_association *asoc,
struct sctp_chunk *chunk,
sctp_cmd_seq_t *commands);
static struct sctp_packet *sctp_ootb_pkt_new(struct net *net,
const struct sctp_association *asoc,
const struct sctp_chunk *chunk);
static void sctp_send_stale_cookie_err(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const struct sctp_chunk *chunk,
sctp_cmd_seq_t *commands,
struct sctp_chunk *err_chunk);
static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands);
static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands);
static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands);
static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
sctp_cmd_seq_t *commands,
__be16 error, int sk_err,
const struct sctp_association *asoc,
struct sctp_transport *transport);
static sctp_disposition_t sctp_sf_abort_violation(
struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
void *arg,
sctp_cmd_seq_t *commands,
const __u8 *payload,
const size_t paylen);
static sctp_disposition_t sctp_sf_violation_chunklen(
struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands);
static sctp_disposition_t sctp_sf_violation_paramlen(
struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg, void *ext,
sctp_cmd_seq_t *commands);
static sctp_disposition_t sctp_sf_violation_ctsn(
struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands);
static sctp_disposition_t sctp_sf_violation_chunk(
struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands);
static sctp_ierror_t sctp_sf_authenticate(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
struct sctp_chunk *chunk);
static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands);
/* Small helper function that checks if the chunk length
* is of the appropriate length. The 'required_length' argument
* is set to be the size of a specific chunk we are testing.
* Return Values: 1 = Valid length
* 0 = Invalid length
*
*/
static inline int
sctp_chunk_length_valid(struct sctp_chunk *chunk,
__u16 required_length)
{
__u16 chunk_length = ntohs(chunk->chunk_hdr->length);
/* Previously already marked? */
if (unlikely(chunk->pdiscard))
return 0;
if (unlikely(chunk_length < required_length))
return 0;
return 1;
}
/**********************************************************
* These are the state functions for handling chunk events.
**********************************************************/
/*
* Process the final SHUTDOWN COMPLETE.
*
* Section: 4 (C) (diagram), 9.2
* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
* that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
* discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
* should stop the T2-shutdown timer and remove all knowledge of the
* association (and thus the association enters the CLOSED state).
*
* Verification Tag: 8.5.1(C), sctpimpguide 2.41.
* C) Rules for packet carrying SHUTDOWN COMPLETE:
* ...
* - The receiver of a SHUTDOWN COMPLETE shall accept the packet
* if the Verification Tag field of the packet matches its own tag and
* the T bit is not set
* OR
* it is set to its peer's tag and the T bit is set in the Chunk
* Flags.
* Otherwise, the receiver MUST silently discard the packet
* and take no further action. An endpoint MUST ignore the
* SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_4_C(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
struct sctp_ulpevent *ev;
if (!sctp_vtag_verify_either(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* RFC 2960 6.10 Bundling
*
* An endpoint MUST NOT bundle INIT, INIT ACK or
* SHUTDOWN COMPLETE with any other chunks.
*/
if (!chunk->singleton)
return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
/* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
/* RFC 2960 10.2 SCTP-to-ULP
*
* H) SHUTDOWN COMPLETE notification
*
* When SCTP completes the shutdown procedures (section 9.2) this
* notification is passed to the upper layer.
*/
ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
0, 0, 0, NULL, GFP_ATOMIC);
if (ev)
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(ev));
/* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
* will verify that it is in SHUTDOWN-ACK-SENT state, if it is
* not the chunk should be discarded. If the endpoint is in
* the SHUTDOWN-ACK-SENT state the endpoint should stop the
* T2-shutdown timer and remove all knowledge of the
* association (and thus the association enters the CLOSED
* state).
*/
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_CLOSED));
SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
return SCTP_DISPOSITION_DELETE_TCB;
}
/*
* Respond to a normal INIT chunk.
* We are the side that is being asked for an association.
*
* Section: 5.1 Normal Establishment of an Association, B
* B) "Z" shall respond immediately with an INIT ACK chunk. The
* destination IP address of the INIT ACK MUST be set to the source
* IP address of the INIT to which this INIT ACK is responding. In
* the response, besides filling in other parameters, "Z" must set the
* Verification Tag field to Tag_A, and also provide its own
* Verification Tag (Tag_Z) in the Initiate Tag field.
*
* Verification Tag: Must be 0.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
struct sctp_chunk *repl;
struct sctp_association *new_asoc;
struct sctp_chunk *err_chunk;
struct sctp_packet *packet;
sctp_unrecognized_param_t *unk_param;
int len;
/* 6.10 Bundling
* An endpoint MUST NOT bundle INIT, INIT ACK or
* SHUTDOWN COMPLETE with any other chunks.
*
* IG Section 2.11.2
* Furthermore, we require that the receiver of an INIT chunk MUST
* enforce these rules by silently discarding an arriving packet
* with an INIT chunk that is bundled with other chunks.
*/
if (!chunk->singleton)
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* If the packet is an OOTB packet which is temporarily on the
* control endpoint, respond with an ABORT.
*/
if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
}
/* 3.1 A packet containing an INIT chunk MUST have a zero Verification
* Tag.
*/
if (chunk->sctp_hdr->vtag != 0)
return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
/* Make sure that the INIT chunk has a valid length.
* Normally, this would cause an ABORT with a Protocol Violation
* error, but since we don't have an association, we'll
* just discard the packet.
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* If the INIT is coming toward a closing socket, we'll send back
* and ABORT. Essentially, this catches the race of INIT being
* backloged to the socket at the same time as the user isses close().
* Since the socket and all its associations are going away, we
* can treat this OOTB
*/
if (sctp_sstate(ep->base.sk, CLOSING))
return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
/* Verify the INIT chunk before processing it. */
err_chunk = NULL;
if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
(sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
&err_chunk)) {
/* This chunk contains fatal error. It is to be discarded.
* Send an ABORT, with causes if there is any.
*/
if (err_chunk) {
packet = sctp_abort_pkt_new(net, ep, asoc, arg,
(__u8 *)(err_chunk->chunk_hdr) +
sizeof(sctp_chunkhdr_t),
ntohs(err_chunk->chunk_hdr->length) -
sizeof(sctp_chunkhdr_t));
sctp_chunk_free(err_chunk);
if (packet) {
sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
SCTP_PACKET(packet));
SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
return SCTP_DISPOSITION_CONSUME;
} else {
return SCTP_DISPOSITION_NOMEM;
}
} else {
return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
commands);
}
}
/* Grab the INIT header. */
chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
/* Tag the variable length parameters. */
chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
if (!new_asoc)
goto nomem;
if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
sctp_scope(sctp_source(chunk)),
GFP_ATOMIC) < 0)
goto nomem_init;
/* The call, sctp_process_init(), can fail on memory allocation. */
if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
(sctp_init_chunk_t *)chunk->chunk_hdr,
GFP_ATOMIC))
goto nomem_init;
/* B) "Z" shall respond immediately with an INIT ACK chunk. */
/* If there are errors need to be reported for unknown parameters,
* make sure to reserve enough room in the INIT ACK for them.
*/
len = 0;
if (err_chunk)
len = ntohs(err_chunk->chunk_hdr->length) -
sizeof(sctp_chunkhdr_t);
repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
if (!repl)
goto nomem_init;
/* If there are errors need to be reported for unknown parameters,
* include them in the outgoing INIT ACK as "Unrecognized parameter"
* parameter.
*/
if (err_chunk) {
/* Get the "Unrecognized parameter" parameter(s) out of the
* ERROR chunk generated by sctp_verify_init(). Since the
* error cause code for "unknown parameter" and the
* "Unrecognized parameter" type is the same, we can
* construct the parameters in INIT ACK by copying the
* ERROR causes over.
*/
unk_param = (sctp_unrecognized_param_t *)
((__u8 *)(err_chunk->chunk_hdr) +
sizeof(sctp_chunkhdr_t));
/* Replace the cause code with the "Unrecognized parameter"
* parameter type.
*/
sctp_addto_chunk(repl, len, unk_param);
sctp_chunk_free(err_chunk);
}
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
/*
* Note: After sending out INIT ACK with the State Cookie parameter,
* "Z" MUST NOT allocate any resources, nor keep any states for the
* new association. Otherwise, "Z" will be vulnerable to resource
* attacks.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
return SCTP_DISPOSITION_DELETE_TCB;
nomem_init:
sctp_association_free(new_asoc);
nomem:
if (err_chunk)
sctp_chunk_free(err_chunk);
return SCTP_DISPOSITION_NOMEM;
}
/*
* Respond to a normal INIT ACK chunk.
* We are the side that is initiating the association.
*
* Section: 5.1 Normal Establishment of an Association, C
* C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
* timer and leave COOKIE-WAIT state. "A" shall then send the State
* Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
* the T1-cookie timer, and enter the COOKIE-ECHOED state.
*
* Note: The COOKIE ECHO chunk can be bundled with any pending outbound
* DATA chunks, but it MUST be the first chunk in the packet and
* until the COOKIE ACK is returned the sender MUST NOT send any
* other packets to the peer.
*
* Verification Tag: 3.3.3
* If the value of the Initiate Tag in a received INIT ACK chunk is
* found to be 0, the receiver MUST treat it as an error and close the
* association by transmitting an ABORT.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
sctp_init_chunk_t *initchunk;
struct sctp_chunk *err_chunk;
struct sctp_packet *packet;
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* 6.10 Bundling
* An endpoint MUST NOT bundle INIT, INIT ACK or
* SHUTDOWN COMPLETE with any other chunks.
*/
if (!chunk->singleton)
return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
/* Make sure that the INIT-ACK chunk has a valid length */
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
/* Grab the INIT header. */
chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
/* Verify the INIT chunk before processing it. */
err_chunk = NULL;
if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
(sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
&err_chunk)) {
sctp_error_t error = SCTP_ERROR_NO_RESOURCE;
/* This chunk contains fatal error. It is to be discarded.
* Send an ABORT, with causes. If there are no causes,
* then there wasn't enough memory. Just terminate
* the association.
*/
if (err_chunk) {
packet = sctp_abort_pkt_new(net, ep, asoc, arg,
(__u8 *)(err_chunk->chunk_hdr) +
sizeof(sctp_chunkhdr_t),
ntohs(err_chunk->chunk_hdr->length) -
sizeof(sctp_chunkhdr_t));
sctp_chunk_free(err_chunk);
if (packet) {
sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
SCTP_PACKET(packet));
SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
error = SCTP_ERROR_INV_PARAM;
}
}
/* SCTP-AUTH, Section 6.3:
* It should be noted that if the receiver wants to tear
* down an association in an authenticated way only, the
* handling of malformed packets should not result in
* tearing down the association.
*
* This means that if we only want to abort associations
* in an authenticated way (i.e AUTH+ABORT), then we
* can't destroy this association just because the packet
* was malformed.
*/
if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
asoc, chunk->transport);
}
/* Tag the variable length parameters. Note that we never
* convert the parameters in an INIT chunk.
*/
chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
SCTP_PEER_INIT(initchunk));
/* Reset init error count upon receipt of INIT-ACK. */
sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
/* 5.1 C) "A" shall stop the T1-init timer and leave
* COOKIE-WAIT state. "A" shall then ... start the T1-cookie
* timer, and enter the COOKIE-ECHOED state.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
/* SCTP-AUTH: genereate the assocition shared keys so that
* we can potentially signe the COOKIE-ECHO.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
/* 5.1 C) "A" shall then send the State Cookie received in the
* INIT ACK chunk in a COOKIE ECHO chunk, ...
*/
/* If there is any errors to report, send the ERROR chunk generated
* for unknown parameters as well.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
SCTP_CHUNK(err_chunk));
return SCTP_DISPOSITION_CONSUME;
}
/*
* Respond to a normal COOKIE ECHO chunk.
* We are the side that is being asked for an association.
*
* Section: 5.1 Normal Establishment of an Association, D
* D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
* with a COOKIE ACK chunk after building a TCB and moving to
* the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
* any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
* chunk MUST be the first chunk in the packet.
*
* IMPLEMENTATION NOTE: An implementation may choose to send the
* Communication Up notification to the SCTP user upon reception
* of a valid COOKIE ECHO chunk.
*
* Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
* D) Rules for packet carrying a COOKIE ECHO
*
* - When sending a COOKIE ECHO, the endpoint MUST use the value of the
* Initial Tag received in the INIT ACK.
*
* - The receiver of a COOKIE ECHO follows the procedures in Section 5.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type, void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
struct sctp_association *new_asoc;
sctp_init_chunk_t *peer_init;
struct sctp_chunk *repl;
struct sctp_ulpevent *ev, *ai_ev = NULL;
int error = 0;
struct sctp_chunk *err_chk_p;
struct sock *sk;
/* If the packet is an OOTB packet which is temporarily on the
* control endpoint, respond with an ABORT.
*/
if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
}
/* Make sure that the COOKIE_ECHO chunk has a valid length.
* In this case, we check that we have enough for at least a
* chunk header. More detailed verification is done
* in sctp_unpack_cookie().
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* If the endpoint is not listening or if the number of associations
* on the TCP-style socket exceed the max backlog, respond with an
* ABORT.
*/
sk = ep->base.sk;
if (!sctp_sstate(sk, LISTENING) ||
(sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
/* "Decode" the chunk. We have no optional parameters so we
* are in good shape.
*/
chunk->subh.cookie_hdr =
(struct sctp_signed_cookie *)chunk->skb->data;
if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
sizeof(sctp_chunkhdr_t)))
goto nomem;
/* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
* "Z" will reply with a COOKIE ACK chunk after building a TCB
* and moving to the ESTABLISHED state.
*/
new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
&err_chk_p);
/* FIXME:
* If the re-build failed, what is the proper error path
* from here?
*
* [We should abort the association. --piggy]
*/
if (!new_asoc) {
/* FIXME: Several errors are possible. A bad cookie should
* be silently discarded, but think about logging it too.
*/
switch (error) {
case -SCTP_IERROR_NOMEM:
goto nomem;
case -SCTP_IERROR_STALE_COOKIE:
sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
err_chk_p);
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
case -SCTP_IERROR_BAD_SIG:
default:
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
}
}
/* Delay state machine commands until later.
*
* Re-build the bind address for the association is done in
* the sctp_unpack_cookie() already.
*/
/* This is a brand-new association, so these are not yet side
* effects--it is safe to run them here.
*/
peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
if (!sctp_process_init(new_asoc, chunk,
&chunk->subh.cookie_hdr->c.peer_addr,
peer_init, GFP_ATOMIC))
goto nomem_init;
/* SCTP-AUTH: Now that we've populate required fields in
* sctp_process_init, set up the assocaition shared keys as
* necessary so that we can potentially authenticate the ACK
*/
error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
if (error)
goto nomem_init;
/* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
* is supposed to be authenticated and we have to do delayed
* authentication. We've just recreated the association using
* the information in the cookie and now it's much easier to
* do the authentication.
*/
if (chunk->auth_chunk) {
struct sctp_chunk auth;
sctp_ierror_t ret;
/* Make sure that we and the peer are AUTH capable */
if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) {
sctp_association_free(new_asoc);
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
}
/* set-up our fake chunk so that we can process it */
auth.skb = chunk->auth_chunk;
auth.asoc = chunk->asoc;
auth.sctp_hdr = chunk->sctp_hdr;
auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
sizeof(sctp_chunkhdr_t));
skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
auth.transport = chunk->transport;
ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth);
if (ret != SCTP_IERROR_NO_ERROR) {
sctp_association_free(new_asoc);
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
}
}
repl = sctp_make_cookie_ack(new_asoc, chunk);
if (!repl)
goto nomem_init;
/* RFC 2960 5.1 Normal Establishment of an Association
*
* D) IMPLEMENTATION NOTE: An implementation may choose to
* send the Communication Up notification to the SCTP user
* upon reception of a valid COOKIE ECHO chunk.
*/
ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
new_asoc->c.sinit_num_ostreams,
new_asoc->c.sinit_max_instreams,
NULL, GFP_ATOMIC);
if (!ev)
goto nomem_ev;
/* Sockets API Draft Section 5.3.1.6
* When a peer sends a Adaptation Layer Indication parameter , SCTP
* delivers this notification to inform the application that of the
* peers requested adaptation layer.
*/
if (new_asoc->peer.adaptation_ind) {
ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
GFP_ATOMIC);
if (!ai_ev)
goto nomem_aiev;
}
/* Add all the state machine commands now since we've created
* everything. This way we don't introduce memory corruptions
* during side-effect processing and correclty count established
* associations.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_ESTABLISHED));
SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
/* This will send the COOKIE ACK */
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
/* Queue the ASSOC_CHANGE event */
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
/* Send up the Adaptation Layer Indication event */
if (ai_ev)
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(ai_ev));
return SCTP_DISPOSITION_CONSUME;
nomem_aiev:
sctp_ulpevent_free(ev);
nomem_ev:
sctp_chunk_free(repl);
nomem_init:
sctp_association_free(new_asoc);
nomem:
return SCTP_DISPOSITION_NOMEM;
}
/*
* Respond to a normal COOKIE ACK chunk.
* We are the side that is being asked for an association.
*
* RFC 2960 5.1 Normal Establishment of an Association
*
* E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
* COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
* timer. It may also notify its ULP about the successful
* establishment of the association with a Communication Up
* notification (see Section 10).
*
* Verification Tag:
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type, void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
struct sctp_ulpevent *ev;
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Verify that the chunk length for the COOKIE-ACK is OK.
* If we don't do this, any bundled chunks may be junked.
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
/* Reset init error count upon receipt of COOKIE-ACK,
* to avoid problems with the managemement of this
* counter in stale cookie situations when a transition back
* from the COOKIE-ECHOED state to the COOKIE-WAIT
* state is performed.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
/* RFC 2960 5.1 Normal Establishment of an Association
*
* E) Upon reception of the COOKIE ACK, endpoint "A" will move
* from the COOKIE-ECHOED state to the ESTABLISHED state,
* stopping the T1-cookie timer.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_ESTABLISHED));
SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
/* It may also notify its ULP about the successful
* establishment of the association with a Communication Up
* notification (see Section 10).
*/
ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
0, asoc->c.sinit_num_ostreams,
asoc->c.sinit_max_instreams,
NULL, GFP_ATOMIC);
if (!ev)
goto nomem;
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
/* Sockets API Draft Section 5.3.1.6
* When a peer sends a Adaptation Layer Indication parameter , SCTP
* delivers this notification to inform the application that of the
* peers requested adaptation layer.
*/
if (asoc->peer.adaptation_ind) {
ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
if (!ev)
goto nomem;
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(ev));
}
return SCTP_DISPOSITION_CONSUME;
nomem:
return SCTP_DISPOSITION_NOMEM;
}
/* Generate and sendout a heartbeat packet. */
static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_transport *transport = (struct sctp_transport *) arg;
struct sctp_chunk *reply;
/* Send a heartbeat to our peer. */
reply = sctp_make_heartbeat(asoc, transport);
if (!reply)
return SCTP_DISPOSITION_NOMEM;
/* Set rto_pending indicating that an RTT measurement
* is started with this heartbeat chunk.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
SCTP_TRANSPORT(transport));
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
return SCTP_DISPOSITION_CONSUME;
}
/* Generate a HEARTBEAT packet on the given transport. */
sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_transport *transport = (struct sctp_transport *) arg;
if (asoc->overall_error_count >= asoc->max_retrans) {
sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
SCTP_ERROR(ETIMEDOUT));
/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
SCTP_PERR(SCTP_ERROR_NO_ERROR));
SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
return SCTP_DISPOSITION_DELETE_TCB;
}
/* Section 3.3.5.
* The Sender-specific Heartbeat Info field should normally include
* information about the sender's current time when this HEARTBEAT
* chunk is sent and the destination transport address to which this
* HEARTBEAT is sent (see Section 8.3).
*/
if (transport->param_flags & SPP_HB_ENABLE) {
if (SCTP_DISPOSITION_NOMEM ==
sctp_sf_heartbeat(ep, asoc, type, arg,
commands))
return SCTP_DISPOSITION_NOMEM;
/* Set transport error counter and association error counter
* when sending heartbeat.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
SCTP_TRANSPORT(transport));
}
sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
SCTP_TRANSPORT(transport));
sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
SCTP_TRANSPORT(transport));
return SCTP_DISPOSITION_CONSUME;
}
/*
* Process an heartbeat request.
*
* Section: 8.3 Path Heartbeat
* The receiver of the HEARTBEAT should immediately respond with a
* HEARTBEAT ACK that contains the Heartbeat Information field copied
* from the received HEARTBEAT chunk.
*
* Verification Tag: 8.5 Verification Tag [Normal verification]
* When receiving an SCTP packet, the endpoint MUST ensure that the
* value in the Verification Tag field of the received SCTP packet
* matches its own Tag. If the received Verification Tag value does not
* match the receiver's own tag value, the receiver shall silently
* discard the packet and shall not process it any further except for
* those cases listed in Section 8.5.1 below.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_beat_8_3(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
sctp_paramhdr_t *param_hdr;
struct sctp_chunk *chunk = arg;
struct sctp_chunk *reply;
size_t paylen = 0;
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the HEARTBEAT chunk has a valid length. */
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
/* 8.3 The receiver of the HEARTBEAT should immediately
* respond with a HEARTBEAT ACK that contains the Heartbeat
* Information field copied from the received HEARTBEAT chunk.
*/
chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr;
paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
if (ntohs(param_hdr->length) > paylen)
return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
param_hdr, commands);
if (!pskb_pull(chunk->skb, paylen))
goto nomem;
reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
if (!reply)
goto nomem;
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
return SCTP_DISPOSITION_CONSUME;
nomem:
return SCTP_DISPOSITION_NOMEM;
}
/*
* Process the returning HEARTBEAT ACK.
*
* Section: 8.3 Path Heartbeat
* Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
* should clear the error counter of the destination transport
* address to which the HEARTBEAT was sent, and mark the destination
* transport address as active if it is not so marked. The endpoint may
* optionally report to the upper layer when an inactive destination
* address is marked as active due to the reception of the latest
* HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
* clear the association overall error count as well (as defined
* in section 8.1).
*
* The receiver of the HEARTBEAT ACK should also perform an RTT
* measurement for that destination transport address using the time
* value carried in the HEARTBEAT ACK chunk.
*
* Verification Tag: 8.5 Verification Tag [Normal verification]
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
union sctp_addr from_addr;
struct sctp_transport *link;
sctp_sender_hb_info_t *hbinfo;
unsigned long max_interval;
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) +
sizeof(sctp_sender_hb_info_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
/* Make sure that the length of the parameter is what we expect */
if (ntohs(hbinfo->param_hdr.length) !=
sizeof(sctp_sender_hb_info_t)) {
return SCTP_DISPOSITION_DISCARD;
}
from_addr = hbinfo->daddr;
link = sctp_assoc_lookup_paddr(asoc, &from_addr);
/* This should never happen, but lets log it if so. */
if (unlikely(!link)) {
if (from_addr.sa.sa_family == AF_INET6) {
net_warn_ratelimited("%s association %p could not find address %pI6\n",
__func__,
asoc,
&from_addr.v6.sin6_addr);
} else {
net_warn_ratelimited("%s association %p could not find address %pI4\n",
__func__,
asoc,
&from_addr.v4.sin_addr.s_addr);
}
return SCTP_DISPOSITION_DISCARD;
}
/* Validate the 64-bit random nonce. */
if (hbinfo->hb_nonce != link->hb_nonce)
return SCTP_DISPOSITION_DISCARD;
max_interval = link->hbinterval + link->rto;
/* Check if the timestamp looks valid. */
if (time_after(hbinfo->sent_at, jiffies) ||
time_after(jiffies, hbinfo->sent_at + max_interval)) {
pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
"for transport:%p\n", __func__, link);
return SCTP_DISPOSITION_DISCARD;
}
/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
* the HEARTBEAT should clear the error counter of the
* destination transport address to which the HEARTBEAT was
* sent and mark the destination transport address as active if
* it is not so marked.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
return SCTP_DISPOSITION_CONSUME;
}
/* Helper function to send out an abort for the restart
* condition.
*/
static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
struct sctp_chunk *init,
sctp_cmd_seq_t *commands)
{
int len;
struct sctp_packet *pkt;
union sctp_addr_param *addrparm;
struct sctp_errhdr *errhdr;
struct sctp_endpoint *ep;
char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
/* Build the error on the stack. We are way to malloc crazy
* throughout the code today.
*/
errhdr = (struct sctp_errhdr *)buffer;
addrparm = (union sctp_addr_param *)errhdr->variable;
/* Copy into a parm format. */
len = af->to_addr_param(ssa, addrparm);
len += sizeof(sctp_errhdr_t);
errhdr->cause = SCTP_ERROR_RESTART;
errhdr->length = htons(len);
/* Assign to the control socket. */
ep = sctp_sk(net->sctp.ctl_sock)->ep;
/* Association is NULL since this may be a restart attack and we
* want to send back the attacker's vtag.
*/
pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
if (!pkt)
goto out;
sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
/* Discard the rest of the inbound packet. */
sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
out:
/* Even if there is no memory, treat as a failure so
* the packet will get dropped.
*/
return 0;
}
static bool list_has_sctp_addr(const struct list_head *list,
union sctp_addr *ipaddr)
{
struct sctp_transport *addr;
list_for_each_entry(addr, list, transports) {
if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
return true;
}
return false;
}
/* A restart is occurring, check to make sure no new addresses
* are being added as we may be under a takeover attack.
*/
static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
const struct sctp_association *asoc,
struct sctp_chunk *init,
sctp_cmd_seq_t *commands)
{
struct net *net = sock_net(new_asoc->base.sk);
struct sctp_transport *new_addr;
int ret = 1;
/* Implementor's Guide - Section 5.2.2
* ...
* Before responding the endpoint MUST check to see if the
* unexpected INIT adds new addresses to the association. If new
* addresses are added to the association, the endpoint MUST respond
* with an ABORT..
*/
/* Search through all current addresses and make sure
* we aren't adding any new ones.
*/
list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
transports) {
if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
&new_addr->ipaddr)) {
sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
commands);
ret = 0;
break;
}
}
/* Return success if all addresses were found. */
return ret;
}
/* Populate the verification/tie tags based on overlapping INIT
* scenario.
*
* Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
*/
static void sctp_tietags_populate(struct sctp_association *new_asoc,
const struct sctp_association *asoc)
{
switch (asoc->state) {
/* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
case SCTP_STATE_COOKIE_WAIT:
new_asoc->c.my_vtag = asoc->c.my_vtag;
new_asoc->c.my_ttag = asoc->c.my_vtag;
new_asoc->c.peer_ttag = 0;
break;
case SCTP_STATE_COOKIE_ECHOED:
new_asoc->c.my_vtag = asoc->c.my_vtag;
new_asoc->c.my_ttag = asoc->c.my_vtag;
new_asoc->c.peer_ttag = asoc->c.peer_vtag;
break;
/* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
* COOKIE-WAIT and SHUTDOWN-ACK-SENT
*/
default:
new_asoc->c.my_ttag = asoc->c.my_vtag;
new_asoc->c.peer_ttag = asoc->c.peer_vtag;
break;
}
/* Other parameters for the endpoint SHOULD be copied from the
* existing parameters of the association (e.g. number of
* outbound streams) into the INIT ACK and cookie.
*/
new_asoc->rwnd = asoc->rwnd;
new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
new_asoc->c.initial_tsn = asoc->c.initial_tsn;
}
/*
* Compare vtag/tietag values to determine unexpected COOKIE-ECHO
* handling action.
*
* RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
*
* Returns value representing action to be taken. These action values
* correspond to Action/Description values in RFC 2960, Table 2.
*/
static char sctp_tietags_compare(struct sctp_association *new_asoc,
const struct sctp_association *asoc)
{
/* In this case, the peer may have restarted. */
if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
(asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
(asoc->c.my_vtag == new_asoc->c.my_ttag) &&
(asoc->c.peer_vtag == new_asoc->c.peer_ttag))
return 'A';
/* Collision case B. */
if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
(0 == asoc->c.peer_vtag))) {
return 'B';
}
/* Collision case D. */
if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
(asoc->c.peer_vtag == new_asoc->c.peer_vtag))
return 'D';
/* Collision case C. */
if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
(asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
(0 == new_asoc->c.my_ttag) &&
(0 == new_asoc->c.peer_ttag))
return 'C';
/* No match to any of the special cases; discard this packet. */
return 'E';
}
/* Common helper routine for both duplicate and simulataneous INIT
* chunk handling.
*/
static sctp_disposition_t sctp_sf_do_unexpected_init(
struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg, sctp_cmd_seq_t *commands)
{
sctp_disposition_t retval;
struct sctp_chunk *chunk = arg;
struct sctp_chunk *repl;
struct sctp_association *new_asoc;
struct sctp_chunk *err_chunk;
struct sctp_packet *packet;
sctp_unrecognized_param_t *unk_param;
int len;
/* 6.10 Bundling
* An endpoint MUST NOT bundle INIT, INIT ACK or
* SHUTDOWN COMPLETE with any other chunks.
*
* IG Section 2.11.2
* Furthermore, we require that the receiver of an INIT chunk MUST
* enforce these rules by silently discarding an arriving packet
* with an INIT chunk that is bundled with other chunks.
*/
if (!chunk->singleton)
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* 3.1 A packet containing an INIT chunk MUST have a zero Verification
* Tag.
*/
if (chunk->sctp_hdr->vtag != 0)
return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
/* Make sure that the INIT chunk has a valid length.
* In this case, we generate a protocol violation since we have
* an association established.
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
/* Grab the INIT header. */
chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
/* Tag the variable length parameters. */
chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
/* Verify the INIT chunk before processing it. */
err_chunk = NULL;
if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
(sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
&err_chunk)) {
/* This chunk contains fatal error. It is to be discarded.
* Send an ABORT, with causes if there is any.
*/
if (err_chunk) {
packet = sctp_abort_pkt_new(net, ep, asoc, arg,
(__u8 *)(err_chunk->chunk_hdr) +
sizeof(sctp_chunkhdr_t),
ntohs(err_chunk->chunk_hdr->length) -
sizeof(sctp_chunkhdr_t));
if (packet) {
sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
SCTP_PACKET(packet));
SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
retval = SCTP_DISPOSITION_CONSUME;
} else {
retval = SCTP_DISPOSITION_NOMEM;
}
goto cleanup;
} else {
return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
commands);
}
}
/*
* Other parameters for the endpoint SHOULD be copied from the
* existing parameters of the association (e.g. number of
* outbound streams) into the INIT ACK and cookie.
* FIXME: We are copying parameters from the endpoint not the
* association.
*/
new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
if (!new_asoc)
goto nomem;
if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
goto nomem;
/* In the outbound INIT ACK the endpoint MUST copy its current
* Verification Tag and Peers Verification tag into a reserved
* place (local tie-tag and per tie-tag) within the state cookie.
*/
if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
(sctp_init_chunk_t *)chunk->chunk_hdr,
GFP_ATOMIC))
goto nomem;
/* Make sure no new addresses are being added during the
* restart. Do not do this check for COOKIE-WAIT state,
* since there are no peer addresses to check against.
* Upon return an ABORT will have been sent if needed.
*/
if (!sctp_state(asoc, COOKIE_WAIT)) {
if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
commands)) {
retval = SCTP_DISPOSITION_CONSUME;
goto nomem_retval;
}
}
sctp_tietags_populate(new_asoc, asoc);
/* B) "Z" shall respond immediately with an INIT ACK chunk. */
/* If there are errors need to be reported for unknown parameters,
* make sure to reserve enough room in the INIT ACK for them.
*/
len = 0;
if (err_chunk) {
len = ntohs(err_chunk->chunk_hdr->length) -
sizeof(sctp_chunkhdr_t);
}
repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
if (!repl)
goto nomem;
/* If there are errors need to be reported for unknown parameters,
* include them in the outgoing INIT ACK as "Unrecognized parameter"
* parameter.
*/
if (err_chunk) {
/* Get the "Unrecognized parameter" parameter(s) out of the
* ERROR chunk generated by sctp_verify_init(). Since the
* error cause code for "unknown parameter" and the
* "Unrecognized parameter" type is the same, we can
* construct the parameters in INIT ACK by copying the
* ERROR causes over.
*/
unk_param = (sctp_unrecognized_param_t *)
((__u8 *)(err_chunk->chunk_hdr) +
sizeof(sctp_chunkhdr_t));
/* Replace the cause code with the "Unrecognized parameter"
* parameter type.
*/
sctp_addto_chunk(repl, len, unk_param);
}
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
/*
* Note: After sending out INIT ACK with the State Cookie parameter,
* "Z" MUST NOT allocate any resources for this new association.
* Otherwise, "Z" will be vulnerable to resource attacks.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
retval = SCTP_DISPOSITION_CONSUME;
return retval;
nomem:
retval = SCTP_DISPOSITION_NOMEM;
nomem_retval:
if (new_asoc)
sctp_association_free(new_asoc);
cleanup:
if (err_chunk)
sctp_chunk_free(err_chunk);
return retval;
}
/*
* Handle simultaneous INIT.
* This means we started an INIT and then we got an INIT request from
* our peer.
*
* Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
* This usually indicates an initialization collision, i.e., each
* endpoint is attempting, at about the same time, to establish an
* association with the other endpoint.
*
* Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
* endpoint MUST respond with an INIT ACK using the same parameters it
* sent in its original INIT chunk (including its Verification Tag,
* unchanged). These original parameters are combined with those from the
* newly received INIT chunk. The endpoint shall also generate a State
* Cookie with the INIT ACK. The endpoint uses the parameters sent in its
* INIT to calculate the State Cookie.
*
* After that, the endpoint MUST NOT change its state, the T1-init
* timer shall be left running and the corresponding TCB MUST NOT be
* destroyed. The normal procedures for handling State Cookies when
* a TCB exists will resolve the duplicate INITs to a single association.
*
* For an endpoint that is in the COOKIE-ECHOED state it MUST populate
* its Tie-Tags with the Tag information of itself and its peer (see
* section 5.2.2 for a description of the Tie-Tags).
*
* Verification Tag: Not explicit, but an INIT can not have a valid
* verification tag, so we skip the check.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
/* Call helper to do the real work for both simulataneous and
* duplicate INIT chunk handling.
*/
return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
}
/*
* Handle duplicated INIT messages. These are usually delayed
* restransmissions.
*
* Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
* COOKIE-ECHOED and COOKIE-WAIT
*
* Unless otherwise stated, upon reception of an unexpected INIT for
* this association, the endpoint shall generate an INIT ACK with a
* State Cookie. In the outbound INIT ACK the endpoint MUST copy its
* current Verification Tag and peer's Verification Tag into a reserved
* place within the state cookie. We shall refer to these locations as
* the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
* containing this INIT ACK MUST carry a Verification Tag value equal to
* the Initiation Tag found in the unexpected INIT. And the INIT ACK
* MUST contain a new Initiation Tag (randomly generated see Section
* 5.3.1). Other parameters for the endpoint SHOULD be copied from the
* existing parameters of the association (e.g. number of outbound
* streams) into the INIT ACK and cookie.
*
* After sending out the INIT ACK, the endpoint shall take no further
* actions, i.e., the existing association, including its current state,
* and the corresponding TCB MUST NOT be changed.
*
* Note: Only when a TCB exists and the association is not in a COOKIE-
* WAIT state are the Tie-Tags populated. For a normal association INIT
* (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
* set to 0 (indicating that no previous TCB existed). The INIT ACK and
* State Cookie are populated as specified in section 5.2.1.
*
* Verification Tag: Not specified, but an INIT has no way of knowing
* what the verification tag could be, so we ignore it.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
/* Call helper to do the real work for both simulataneous and
* duplicate INIT chunk handling.
*/
return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
}
/*
* Unexpected INIT-ACK handler.
*
* Section 5.2.3
* If an INIT ACK received by an endpoint in any state other than the
* COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
* An unexpected INIT ACK usually indicates the processing of an old or
* duplicated INIT chunk.
*/
sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg, sctp_cmd_seq_t *commands)
{
/* Per the above section, we'll discard the chunk if we have an
* endpoint. If this is an OOTB INIT-ACK, treat it as such.
*/
if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
else
return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
}
/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
*
* Section 5.2.4
* A) In this case, the peer may have restarted.
*/
static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
struct sctp_chunk *chunk,
sctp_cmd_seq_t *commands,
struct sctp_association *new_asoc)
{
sctp_init_chunk_t *peer_init;
struct sctp_ulpevent *ev;
struct sctp_chunk *repl;
struct sctp_chunk *err;
sctp_disposition_t disposition;
/* new_asoc is a brand-new association, so these are not yet
* side effects--it is safe to run them here.
*/
peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
GFP_ATOMIC))
goto nomem;
/* Make sure no new addresses are being added during the
* restart. Though this is a pretty complicated attack
* since you'd have to get inside the cookie.
*/
if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
return SCTP_DISPOSITION_CONSUME;
}
/* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
* the peer has restarted (Action A), it MUST NOT setup a new
* association but instead resend the SHUTDOWN ACK and send an ERROR
* chunk with a "Cookie Received while Shutting Down" error cause to
* its peer.
*/
if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc,
SCTP_ST_CHUNK(chunk->chunk_hdr->type),
chunk, commands);
if (SCTP_DISPOSITION_NOMEM == disposition)
goto nomem;
err = sctp_make_op_error(asoc, chunk,
SCTP_ERROR_COOKIE_IN_SHUTDOWN,
NULL, 0, 0);
if (err)
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
SCTP_CHUNK(err));
return SCTP_DISPOSITION_CONSUME;
}
/* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
* data. Consider the optional choice of resending of this data.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
/* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
* and ASCONF-ACK cache.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
repl = sctp_make_cookie_ack(new_asoc, chunk);
if (!repl)
goto nomem;
/* Report association restart to upper layer. */
ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
new_asoc->c.sinit_num_ostreams,
new_asoc->c.sinit_max_instreams,
NULL, GFP_ATOMIC);
if (!ev)
goto nomem_ev;
/* Update the content of current association. */
sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
if (sctp_state(asoc, SHUTDOWN_PENDING) &&
(sctp_sstate(asoc->base.sk, CLOSING) ||
sock_flag(asoc->base.sk, SOCK_DEAD))) {
/* if were currently in SHUTDOWN_PENDING, but the socket
* has been closed by user, don't transition to ESTABLISHED.
* Instead trigger SHUTDOWN bundled with COOKIE_ACK.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
SCTP_ST_CHUNK(0), NULL,
commands);
} else {
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_ESTABLISHED));
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
}
return SCTP_DISPOSITION_CONSUME;
nomem_ev:
sctp_chunk_free(repl);
nomem:
return SCTP_DISPOSITION_NOMEM;
}
/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
*
* Section 5.2.4
* B) In this case, both sides may be attempting to start an association
* at about the same time but the peer endpoint started its INIT
* after responding to the local endpoint's INIT
*/
/* This case represents an initialization collision. */
static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
struct sctp_chunk *chunk,
sctp_cmd_seq_t *commands,
struct sctp_association *new_asoc)
{
sctp_init_chunk_t *peer_init;
struct sctp_chunk *repl;
/* new_asoc is a brand-new association, so these are not yet
* side effects--it is safe to run them here.
*/
peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
GFP_ATOMIC))
goto nomem;
/* Update the content of current association. */
sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_ESTABLISHED));
SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
repl = sctp_make_cookie_ack(new_asoc, chunk);
if (!repl)
goto nomem;
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
/* RFC 2960 5.1 Normal Establishment of an Association
*
* D) IMPLEMENTATION NOTE: An implementation may choose to
* send the Communication Up notification to the SCTP user
* upon reception of a valid COOKIE ECHO chunk.
*
* Sadly, this needs to be implemented as a side-effect, because
* we are not guaranteed to have set the association id of the real
* association and so these notifications need to be delayed until
* the association id is allocated.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
/* Sockets API Draft Section 5.3.1.6
* When a peer sends a Adaptation Layer Indication parameter , SCTP
* delivers this notification to inform the application that of the
* peers requested adaptation layer.
*
* This also needs to be done as a side effect for the same reason as
* above.
*/
if (asoc->peer.adaptation_ind)
sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
return SCTP_DISPOSITION_CONSUME;
nomem:
return SCTP_DISPOSITION_NOMEM;
}
/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
*
* Section 5.2.4
* C) In this case, the local endpoint's cookie has arrived late.
* Before it arrived, the local endpoint sent an INIT and received an
* INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
* but a new tag of its own.
*/
/* This case represents an initialization collision. */
static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
struct sctp_chunk *chunk,
sctp_cmd_seq_t *commands,
struct sctp_association *new_asoc)
{
/* The cookie should be silently discarded.
* The endpoint SHOULD NOT change states and should leave
* any timers running.
*/
return SCTP_DISPOSITION_DISCARD;
}
/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
*
* Section 5.2.4
*
* D) When both local and remote tags match the endpoint should always
* enter the ESTABLISHED state, if it has not already done so.
*/
/* This case represents an initialization collision. */
static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
struct sctp_chunk *chunk,
sctp_cmd_seq_t *commands,
struct sctp_association *new_asoc)
{
struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
struct sctp_chunk *repl;
/* Clarification from Implementor's Guide:
* D) When both local and remote tags match the endpoint should
* enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
* It should stop any cookie timer that may be running and send
* a COOKIE ACK.
*/
/* Don't accidentally move back into established state. */
if (asoc->state < SCTP_STATE_ESTABLISHED) {
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_ESTABLISHED));
SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
SCTP_NULL());
/* RFC 2960 5.1 Normal Establishment of an Association
*
* D) IMPLEMENTATION NOTE: An implementation may choose
* to send the Communication Up notification to the
* SCTP user upon reception of a valid COOKIE
* ECHO chunk.
*/
ev = sctp_ulpevent_make_assoc_change(asoc, 0,
SCTP_COMM_UP, 0,
asoc->c.sinit_num_ostreams,
asoc->c.sinit_max_instreams,
NULL, GFP_ATOMIC);
if (!ev)
goto nomem;
/* Sockets API Draft Section 5.3.1.6
* When a peer sends a Adaptation Layer Indication parameter,
* SCTP delivers this notification to inform the application
* that of the peers requested adaptation layer.
*/
if (asoc->peer.adaptation_ind) {
ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
GFP_ATOMIC);
if (!ai_ev)
goto nomem;
}
}
repl = sctp_make_cookie_ack(new_asoc, chunk);
if (!repl)
goto nomem;
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
if (ev)
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(ev));
if (ai_ev)
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(ai_ev));
return SCTP_DISPOSITION_CONSUME;
nomem:
if (ai_ev)
sctp_ulpevent_free(ai_ev);
if (ev)
sctp_ulpevent_free(ev);
return SCTP_DISPOSITION_NOMEM;
}
/*
* Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
* chunk was retransmitted and then delayed in the network.
*
* Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
*
* Verification Tag: None. Do cookie validation.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
sctp_disposition_t retval;
struct sctp_chunk *chunk = arg;
struct sctp_association *new_asoc;
int error = 0;
char action;
struct sctp_chunk *err_chk_p;
/* Make sure that the chunk has a valid length from the protocol
* perspective. In this case check to make sure we have at least
* enough for the chunk header. Cookie length verification is
* done later.
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
/* "Decode" the chunk. We have no optional parameters so we
* are in good shape.
*/
chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
sizeof(sctp_chunkhdr_t)))
goto nomem;
/* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
* of a duplicate COOKIE ECHO match the Verification Tags of the
* current association, consider the State Cookie valid even if
* the lifespan is exceeded.
*/
new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
&err_chk_p);
/* FIXME:
* If the re-build failed, what is the proper error path
* from here?
*
* [We should abort the association. --piggy]
*/
if (!new_asoc) {
/* FIXME: Several errors are possible. A bad cookie should
* be silently discarded, but think about logging it too.
*/
switch (error) {
case -SCTP_IERROR_NOMEM:
goto nomem;
case -SCTP_IERROR_STALE_COOKIE:
sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
err_chk_p);
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
case -SCTP_IERROR_BAD_SIG:
default:
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
}
}
/* Compare the tie_tag in cookie with the verification tag of
* current association.
*/
action = sctp_tietags_compare(new_asoc, asoc);
switch (action) {
case 'A': /* Association restart. */
retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
new_asoc);
break;
case 'B': /* Collision case B. */
retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
new_asoc);
break;
case 'C': /* Collision case C. */
retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
new_asoc);
break;
case 'D': /* Collision case D. */
retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
new_asoc);
break;
default: /* Discard packet for all others. */
retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
break;
}
/* Delete the tempory new association. */
sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
/* Restore association pointer to provide SCTP command interpeter
* with a valid context in case it needs to manipulate
* the queues */
sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
SCTP_ASOC((struct sctp_association *)asoc));
return retval;
nomem:
return SCTP_DISPOSITION_NOMEM;
}
/*
* Process an ABORT. (SHUTDOWN-PENDING state)
*
* See sctp_sf_do_9_1_abort().
*/
sctp_disposition_t sctp_sf_shutdown_pending_abort(
struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
if (!sctp_vtag_verify_either(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the ABORT chunk has a valid length.
* Since this is an ABORT chunk, we have to discard it
* because of the following text:
* RFC 2960, Section 3.3.7
* If an endpoint receives an ABORT with a format error or for an
* association that doesn't exist, it MUST silently discard it.
* Because the length is "invalid", we can't really discard just
* as we do not know its true length. So, to be safe, discard the
* packet.
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* ADD-IP: Special case for ABORT chunks
* F4) One special consideration is that ABORT Chunks arriving
* destined to the IP address being deleted MUST be
* ignored (see Section 5.3.1 for further details).
*/
if (SCTP_ADDR_DEL ==
sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
}
/*
* Process an ABORT. (SHUTDOWN-SENT state)
*
* See sctp_sf_do_9_1_abort().
*/
sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
if (!sctp_vtag_verify_either(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the ABORT chunk has a valid length.
* Since this is an ABORT chunk, we have to discard it
* because of the following text:
* RFC 2960, Section 3.3.7
* If an endpoint receives an ABORT with a format error or for an
* association that doesn't exist, it MUST silently discard it.
* Because the length is "invalid", we can't really discard just
* as we do not know its true length. So, to be safe, discard the
* packet.
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* ADD-IP: Special case for ABORT chunks
* F4) One special consideration is that ABORT Chunks arriving
* destined to the IP address being deleted MUST be
* ignored (see Section 5.3.1 for further details).
*/
if (SCTP_ADDR_DEL ==
sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
/* Stop the T2-shutdown timer. */
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
/* Stop the T5-shutdown guard timer. */
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
}
/*
* Process an ABORT. (SHUTDOWN-ACK-SENT state)
*
* See sctp_sf_do_9_1_abort().
*/
sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
/* The same T2 timer, so we should be able to use
* common function with the SHUTDOWN-SENT state.
*/
return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
}
/*
* Handle an Error received in COOKIE_ECHOED state.
*
* Only handle the error type of stale COOKIE Error, the other errors will
* be ignored.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
sctp_errhdr_t *err;
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the ERROR chunk has a valid length.
* The parameter walking depends on this as well.
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
/* Process the error here */
/* FUTURE FIXME: When PR-SCTP related and other optional
* parms are emitted, this will have to change to handle multiple
* errors.
*/
sctp_walk_errors(err, chunk->chunk_hdr) {
if (SCTP_ERROR_STALE_COOKIE == err->cause)
return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
arg, commands);
}
/* It is possible to have malformed error causes, and that
* will cause us to end the walk early. However, since
* we are discarding the packet, there should be no adverse
* affects.
*/
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
}
/*
* Handle a Stale COOKIE Error
*
* Section: 5.2.6 Handle Stale COOKIE Error
* If the association is in the COOKIE-ECHOED state, the endpoint may elect
* one of the following three alternatives.
* ...
* 3) Send a new INIT chunk to the endpoint, adding a Cookie
* Preservative parameter requesting an extension to the lifetime of
* the State Cookie. When calculating the time extension, an
* implementation SHOULD use the RTT information measured based on the
* previous COOKIE ECHO / ERROR exchange, and should add no more
* than 1 second beyond the measured RTT, due to long State Cookie
* lifetimes making the endpoint more subject to a replay attack.
*
* Verification Tag: Not explicit, but safe to ignore.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
time_t stale;
sctp_cookie_preserve_param_t bht;
sctp_errhdr_t *err;
struct sctp_chunk *reply;
struct sctp_bind_addr *bp;
int attempts = asoc->init_err_counter + 1;
if (attempts > asoc->max_init_attempts) {
sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
SCTP_ERROR(ETIMEDOUT));
sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
return SCTP_DISPOSITION_DELETE_TCB;
}
err = (sctp_errhdr_t *)(chunk->skb->data);
/* When calculating the time extension, an implementation
* SHOULD use the RTT information measured based on the
* previous COOKIE ECHO / ERROR exchange, and should add no
* more than 1 second beyond the measured RTT, due to long
* State Cookie lifetimes making the endpoint more subject to
* a replay attack.
* Measure of Staleness's unit is usec. (1/1000000 sec)
* Suggested Cookie Life-span Increment's unit is msec.
* (1/1000 sec)
* In general, if you use the suggested cookie life, the value
* found in the field of measure of staleness should be doubled
* to give ample time to retransmit the new cookie and thus
* yield a higher probability of success on the reattempt.
*/
stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
stale = (stale * 2) / 1000;
bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
bht.param_hdr.length = htons(sizeof(bht));
bht.lifespan_increment = htonl(stale);
/* Build that new INIT chunk. */
bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
if (!reply)
goto nomem;
sctp_addto_chunk(reply, sizeof(bht), &bht);
/* Clear peer's init_tag cached in assoc as we are sending a new INIT */
sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
/* Stop pending T3-rtx and heartbeat timers */
sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
/* Delete non-primary peer ip addresses since we are transitioning
* back to the COOKIE-WAIT state
*/
sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
/* If we've sent any data bundled with COOKIE-ECHO we will need to
* resend
*/
sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
SCTP_TRANSPORT(asoc->peer.primary_path));
/* Cast away the const modifier, as we want to just
* rerun it through as a sideffect.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
return SCTP_DISPOSITION_CONSUME;
nomem:
return SCTP_DISPOSITION_NOMEM;
}
/*
* Process an ABORT.
*
* Section: 9.1
* After checking the Verification Tag, the receiving endpoint shall
* remove the association from its record, and shall report the
* termination to its upper layer.
*
* Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
* B) Rules for packet carrying ABORT:
*
* - The endpoint shall always fill in the Verification Tag field of the
* outbound packet with the destination endpoint's tag value if it
* is known.
*
* - If the ABORT is sent in response to an OOTB packet, the endpoint
* MUST follow the procedure described in Section 8.4.
*
* - The receiver MUST accept the packet if the Verification Tag
* matches either its own tag, OR the tag of its peer. Otherwise, the
* receiver MUST silently discard the packet and take no further
* action.
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
if (!sctp_vtag_verify_either(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the ABORT chunk has a valid length.
* Since this is an ABORT chunk, we have to discard it
* because of the following text:
* RFC 2960, Section 3.3.7
* If an endpoint receives an ABORT with a format error or for an
* association that doesn't exist, it MUST silently discard it.
* Because the length is "invalid", we can't really discard just
* as we do not know its true length. So, to be safe, discard the
* packet.
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* ADD-IP: Special case for ABORT chunks
* F4) One special consideration is that ABORT Chunks arriving
* destined to the IP address being deleted MUST be
* ignored (see Section 5.3.1 for further details).
*/
if (SCTP_ADDR_DEL ==
sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
}
static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
unsigned int len;
__be16 error = SCTP_ERROR_NO_ERROR;
/* See if we have an error cause code in the chunk. */
len = ntohs(chunk->chunk_hdr->length);
if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
sctp_errhdr_t *err;
sctp_walk_errors(err, chunk->chunk_hdr);
if ((void *)err != (void *)chunk->chunk_end)
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
}
sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
/* ASSOC_FAILED will DELETE_TCB. */
sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
return SCTP_DISPOSITION_ABORT;
}
/*
* Process an ABORT. (COOKIE-WAIT state)
*
* See sctp_sf_do_9_1_abort() above.
*/
sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
unsigned int len;
__be16 error = SCTP_ERROR_NO_ERROR;
if (!sctp_vtag_verify_either(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the ABORT chunk has a valid length.
* Since this is an ABORT chunk, we have to discard it
* because of the following text:
* RFC 2960, Section 3.3.7
* If an endpoint receives an ABORT with a format error or for an
* association that doesn't exist, it MUST silently discard it.
* Because the length is "invalid", we can't really discard just
* as we do not know its true length. So, to be safe, discard the
* packet.
*/
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* See if we have an error cause code in the chunk. */
len = ntohs(chunk->chunk_hdr->length);
if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
chunk->transport);
}
/*
* Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
*/
sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
ENOPROTOOPT, asoc,
(struct sctp_transport *)arg);
}
/*
* Process an ABORT. (COOKIE-ECHOED state)
*/
sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
/* There is a single T1 timer, so we should be able to use
* common function with the COOKIE-WAIT state.
*/
return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
}
/*
* Stop T1 timer and abort association with "INIT failed".
*
* This is common code called by several sctp_sf_*_abort() functions above.
*/
static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
sctp_cmd_seq_t *commands,
__be16 error, int sk_err,
const struct sctp_association *asoc,
struct sctp_transport *transport)
{
pr_debug("%s: ABORT received (INIT)\n", __func__);
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_CLOSED));
SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
/* CMD_INIT_FAILED will DELETE_TCB. */
sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
SCTP_PERR(error));
return SCTP_DISPOSITION_ABORT;
}
/*
* sctp_sf_do_9_2_shut
*
* Section: 9.2
* Upon the reception of the SHUTDOWN, the peer endpoint shall
* - enter the SHUTDOWN-RECEIVED state,
*
* - stop accepting new data from its SCTP user
*
* - verify, by checking the Cumulative TSN Ack field of the chunk,
* that all its outstanding DATA chunks have been received by the
* SHUTDOWN sender.
*
* Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
* send a SHUTDOWN in response to a ULP request. And should discard
* subsequent SHUTDOWN chunks.
*
* If there are still outstanding DATA chunks left, the SHUTDOWN
* receiver shall continue to follow normal data transmission
* procedures defined in Section 6 until all outstanding DATA chunks
* are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
* new data from its SCTP user.
*
* Verification Tag: 8.5 Verification Tag [Normal verification]
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
sctp_shutdownhdr_t *sdh;
sctp_disposition_t disposition;
struct sctp_ulpevent *ev;
__u32 ctsn;
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the SHUTDOWN chunk has a valid length. */
if (!sctp_chunk_length_valid(chunk,
sizeof(struct sctp_shutdown_chunk_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
/* Convert the elaborate header. */
sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
chunk->subh.shutdown_hdr = sdh;
ctsn = ntohl(sdh->cum_tsn_ack);
if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
asoc->ctsn_ack_point);
return SCTP_DISPOSITION_DISCARD;
}
/* If Cumulative TSN Ack beyond the max tsn currently
* send, terminating the association and respond to the
* sender with an ABORT.
*/
if (!TSN_lt(ctsn, asoc->next_tsn))
return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
/* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
* When a peer sends a SHUTDOWN, SCTP delivers this notification to
* inform the application that it should cease sending data.
*/
ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
if (!ev) {
disposition = SCTP_DISPOSITION_NOMEM;
goto out;
}
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
/* Upon the reception of the SHUTDOWN, the peer endpoint shall
* - enter the SHUTDOWN-RECEIVED state,
* - stop accepting new data from its SCTP user
*
* [This is implicit in the new state.]
*/
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
disposition = SCTP_DISPOSITION_CONSUME;
if (sctp_outq_is_empty(&asoc->outqueue)) {
disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
arg, commands);
}
if (SCTP_DISPOSITION_NOMEM == disposition)
goto out;
/* - verify, by checking the Cumulative TSN Ack field of the
* chunk, that all its outstanding DATA chunks have been
* received by the SHUTDOWN sender.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
out:
return disposition;
}
/*
* sctp_sf_do_9_2_shut_ctsn
*
* Once an endpoint has reached the SHUTDOWN-RECEIVED state,
* it MUST NOT send a SHUTDOWN in response to a ULP request.
* The Cumulative TSN Ack of the received SHUTDOWN chunk
* MUST be processed.
*/
sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
sctp_shutdownhdr_t *sdh;
__u32 ctsn;
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the SHUTDOWN chunk has a valid length. */
if (!sctp_chunk_length_valid(chunk,
sizeof(struct sctp_shutdown_chunk_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
ctsn = ntohl(sdh->cum_tsn_ack);
if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
asoc->ctsn_ack_point);
return SCTP_DISPOSITION_DISCARD;
}
/* If Cumulative TSN Ack beyond the max tsn currently
* send, terminating the association and respond to the
* sender with an ABORT.
*/
if (!TSN_lt(ctsn, asoc->next_tsn))
return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
/* verify, by checking the Cumulative TSN Ack field of the
* chunk, that all its outstanding DATA chunks have been
* received by the SHUTDOWN sender.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
SCTP_BE32(sdh->cum_tsn_ack));
return SCTP_DISPOSITION_CONSUME;
}
/* RFC 2960 9.2
* If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
* (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
* transport addresses (either in the IP addresses or in the INIT chunk)
* that belong to this association, it should discard the INIT chunk and
* retransmit the SHUTDOWN ACK chunk.
*/
sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
struct sctp_chunk *reply;
/* Make sure that the chunk has a valid length */
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
/* Since we are not going to really process this INIT, there
* is no point in verifying chunk boundries. Just generate
* the SHUTDOWN ACK.
*/
reply = sctp_make_shutdown_ack(asoc, chunk);
if (NULL == reply)
goto nomem;
/* Set the transport for the SHUTDOWN ACK chunk and the timeout for
* the T2-SHUTDOWN timer.
*/
sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
/* and restart the T2-shutdown timer. */
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
return SCTP_DISPOSITION_CONSUME;
nomem:
return SCTP_DISPOSITION_NOMEM;
}
/*
* sctp_sf_do_ecn_cwr
*
* Section: Appendix A: Explicit Congestion Notification
*
* CWR:
*
* RFC 2481 details a specific bit for a sender to send in the header of
* its next outbound TCP segment to indicate to its peer that it has
* reduced its congestion window. This is termed the CWR bit. For
* SCTP the same indication is made by including the CWR chunk.
* This chunk contains one data element, i.e. the TSN number that
* was sent in the ECNE chunk. This element represents the lowest
* TSN number in the datagram that was originally marked with the
* CE bit.
*
* Verification Tag: 8.5 Verification Tag [Normal verification]
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
sctp_cwrhdr_t *cwr;
struct sctp_chunk *chunk = arg;
u32 lowest_tsn;
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
cwr = (sctp_cwrhdr_t *) chunk->skb->data;
skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
lowest_tsn = ntohl(cwr->lowest_tsn);
/* Does this CWR ack the last sent congestion notification? */
if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
/* Stop sending ECNE. */
sctp_add_cmd_sf(commands,
SCTP_CMD_ECN_CWR,
SCTP_U32(lowest_tsn));
}
return SCTP_DISPOSITION_CONSUME;
}
/*
* sctp_sf_do_ecne
*
* Section: Appendix A: Explicit Congestion Notification
*
* ECN-Echo
*
* RFC 2481 details a specific bit for a receiver to send back in its
* TCP acknowledgements to notify the sender of the Congestion
* Experienced (CE) bit having arrived from the network. For SCTP this
* same indication is made by including the ECNE chunk. This chunk
* contains one data element, i.e. the lowest TSN associated with the IP
* datagram marked with the CE bit.....
*
* Verification Tag: 8.5 Verification Tag [Normal verification]
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*
* The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_do_ecne(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
sctp_ecnehdr_t *ecne;
struct sctp_chunk *chunk = arg;
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
commands);
ecne = (sctp_ecnehdr_t *) chunk->skb->data;
skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
/* If this is a newer ECNE than the last CWR packet we sent out */
sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
SCTP_U32(ntohl(ecne->lowest_tsn)));
return SCTP_DISPOSITION_CONSUME;
}
/*
* Section: 6.2 Acknowledgement on Reception of DATA Chunks
*
* The SCTP endpoint MUST always acknowledge the reception of each valid
* DATA chunk.
*
* The guidelines on delayed acknowledgement algorithm specified in
* Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
* acknowledgement SHOULD be generated for at least every second packet
* (not every second DATA chunk) received, and SHOULD be generated within
* 200 ms of the arrival of any unacknowledged DATA chunk. In some
* situations it may be beneficial for an SCTP transmitter to be more
* conservative than the algorithms detailed in this document allow.
* However, an SCTP transmitter MUST NOT be more aggressive than the
* following algorithms allow.
*
* A SCTP receiver MUST NOT generate more than one SACK for every
* incoming packet, other than to update the offered window as the
* receiving application consumes new data.
*
* Verification Tag: 8.5 Verification Tag [Normal verification]
*
* Inputs
* (endpoint, asoc, chunk)
*
* Outputs
* (asoc, reply_msg, msg_up, timers, counters)
*