/* SCTP kernel reference Implementation
* (C) Copyright IBM Corp. 2001, 2004
* Copyright (c) 1999 Cisco, Inc.
* Copyright (c) 1999-2001 Motorola, Inc.
*
* This file is part of the SCTP kernel reference Implementation
*
* These functions work with the state functions in sctp_sm_statefuns.c
* to implement that state operations. These functions implement the
* steps which require modifying existing data structures.
*
* The SCTP reference implementation is free software;
* you can redistribute it and/or modify it under the terms of
* the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* The SCTP reference implementation is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* ************************
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <lksctp-developers@lists.sourceforge.net>
*
* Or submit a bug report through the following website:
* http://www.sf.net/projects/lksctp
*
* Written or modified by:
* La Monte H.P. Yarroll <piggy@acm.org>
* Karl Knutson <karl@athena.chicago.il.us>
* Jon Grimm <jgrimm@austin.ibm.com>
* Hui Huang <hui.huang@nokia.com>
* Dajiang Zhang <dajiang.zhang@nokia.com>
* Daisy Chang <daisyc@us.ibm.com>
* Sridhar Samudrala <sri@us.ibm.com>
* Ardelle Fan <ardelle.fan@intel.com>
*
* Any bugs reported given to us we will try to fix... any fixes shared will
* be incorporated into the next SCTP release.
*/
#include <linux/skbuff.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/ip.h>
#include <net/sock.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
static int sctp_cmd_interpreter(sctp_event_t event_type,
sctp_subtype_t subtype,
sctp_state_t state,
struct sctp_endpoint *ep,
struct sctp_association *asoc,
void *event_arg,
sctp_disposition_t status,
sctp_cmd_seq_t *commands,
unsigned int __nocast gfp);
static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
sctp_state_t state,
struct sctp_endpoint *ep,
struct sctp_association *asoc,
void *event_arg,
sctp_disposition_t status,
sctp_cmd_seq_t *commands,
unsigned int __nocast gfp);
/********************************************************************
* Helper functions
********************************************************************/
/* A helper function for delayed processing of INET ECN CE bit. */
static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
__u32 lowest_tsn)
{
/* Save the TSN away for comparison when we receive CWR */
asoc->last_ecne_tsn = lowest_tsn;
asoc->need_ecne = 1;
}
/* Helper function for delayed processing of SCTP ECNE chunk. */
/* RFC 2960 Appendix A
*
* 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.
*/
static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
__u32 lowest_tsn,
struct sctp_chunk *chunk)
{
struct sctp_chunk *repl;
/* Our previously transmitted packet ran into some congestion
* so we should take action by reducing cwnd and ssthresh
* and then ACK our peer that we we've done so by
* sending a CWR.
*/
/* First, try to determine if we want to actually lower
* our cwnd variables. Only lower them if the ECNE looks more
* recent than the last response.
*/
if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
struct sctp_transport *transport;
/* Find which transport's congestion variables
* need to be adjusted.
*/
transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
/* Update the congestion variables. */
if (transport)
sctp_transport_lower_cwnd(transport,
SCTP_LOWER_CWND_ECNE);
asoc->last_cwr_tsn = lowest_tsn;
}
/* Always try to quiet the other end. In case of lost CWR,
* resend last_cwr_tsn.
*/
repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
/* If we run out of memory, it will look like a lost CWR. We'll
* get back in sync eventually.
*/
return repl;
}
/* Helper function to do delayed processing of ECN CWR chunk. */
static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
__u32 lowest_tsn)
{
/* Turn off ECNE getting auto-prepended to every outgoing
* packet
*/
asoc->need_ecne = 0;
}
/* Generate SACK if necessary. We call this at the end of a packet. */
static int sctp_gen_sack(struct sctp_association *asoc, int force,
sctp_cmd_seq_t *commands)
{
__u32 ctsn, max_tsn_seen;
struct sctp_chunk *sack;
int error = 0;
if (force)
asoc->peer.sack_needed = 1;
ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
/* From 12.2 Parameters necessary per association (i.e. the TCB):
*
* Ack State : This flag indicates if the next received packet
* : is to be responded to with a SACK. ...
* : When DATA chunks are out of order, SACK's
* : are not delayed (see Section 6).
*
* [This is actually not mentioned in Section 6, but we
* implement it here anyway. --piggy]
*/
if (max_tsn_seen != ctsn)
asoc->peer.sack_needed = 1;
/* From 6.2 Acknowledgement on Reception of DATA Chunks:
*
* 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. ...
*/
if (!asoc->peer.sack_needed) {
/* We will need a SACK for the next packet. */
asoc->peer.sack_needed = 1;
goto out;
} else {
if (asoc->a_rwnd > asoc->rwnd)
asoc->a_rwnd = asoc->rwnd;
sack = sctp_make_sack(asoc);
if (!sack)
goto nomem;
asoc->peer.sack_needed = 0;
error = sctp_outq_tail(&asoc->outqueue, sack);
/* Stop the SACK timer. */
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
}
out:
return error;
nomem:
error = -ENOMEM;
return error;
}
/* When the T3-RTX timer expires, it calls this function to create the
* relevant state machine event.
*/
void sctp_generate_t3_rtx_event(unsigned long peer)
{
int error;
struct sctp_transport *transport = (struct sctp_transport *) peer;
struct sctp_association *asoc = transport->asoc;
/* Check whether a task is in the sock. */
sctp_bh_lock_sock(asoc->base.sk);
if (sock_owned_by_user(asoc->base.sk)) {
SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__);
/* Try again later. */
if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
sctp_transport_hold(transport);
goto out_unlock;
}
/* Is this transport really dead and just waiting around for
* the timer to let go of the reference?
*/
if (transport->dead)
goto out_unlock;
/* Run through the state machine. */
error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
asoc->state,
asoc->ep, asoc,
transport, GFP_ATOMIC);
if (error)
asoc->base.sk->sk_err = -error;
out_unlock:
sctp_bh_unlock_sock(asoc->base.sk);
sctp_transport_put(transport);
}
/* This is a sa interface for producing timeout events. It works
* for timeouts which use the association as their parameter.
*/
static void sctp_generate_timeout_event(struct sctp_association *asoc,
sctp_event_timeout_t timeout_type)
{
int error = 0;
sctp_bh_lock_sock(asoc->base.sk);
if (sock_owned_by_user(asoc->base.sk)) {
SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
__FUNCTION__,
timeout_type);
/* Try again later. */
if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
sctp_association_hold(asoc);
goto out_unlock;
}
/* Is this association really dead and just waiting around for
* the timer to let go of the reference?
*/
if (asoc->base.dead)
goto out_unlock;
/* Run through the state machine. */
error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
SCTP_ST_TIMEOUT(timeout_type),
asoc->state, asoc->ep, asoc,
(void *)timeout_type, GFP_ATOMIC);
if (error)
asoc->base.sk->sk_err = -error;
out_unlock:
sctp_bh_unlock_sock(asoc->base.sk);
sctp_association_put(asoc);
}
static void sctp_generate_t1_cookie_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
}
static void sctp_generate_t1_init_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
}
static void sctp_generate_t2_shutdown_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
}
static void sctp_generate_t4_rto_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
}
static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *)data;
sctp_generate_timeout_event(asoc,
SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
} /* sctp_generate_t5_shutdown_guard_event() */
static void sctp_generate_autoclose_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
}
/* Generate a heart beat event. If the sock is busy, reschedule. Make
* sure that the transport is still valid.
*/
void sctp_generate_heartbeat_event(unsigned long data)
{
int error = 0;
struct sctp_transport *transport = (struct sctp_transport *) data;
struct sctp_association *asoc = transport->asoc;
sctp_bh_lock_sock(asoc->base.sk);
if (sock_owned_by_user(asoc->base.sk)) {
SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__);
/* Try again later. */
if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
sctp_transport_hold(transport);
goto out_unlock;
}
/* Is this structure just waiting around for us to actually
* get destroyed?
*/
if (transport->dead)
goto out_unlock;
error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
asoc->state, asoc->ep, asoc,
transport, GFP_ATOMIC);
if (error)
asoc->base.sk->sk_err = -error;
out_unlock:
sctp_bh_unlock_sock(asoc->base.sk);
sctp_transport_put(transport);
}
/* Inject a SACK Timeout event into the state machine. */
static void sctp_generate_sack_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
}
sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
NULL,
sctp_generate_t1_cookie_event,
sctp_generate_t1_init_event,
sctp_generate_t2_shutdown_event,
NULL,
sctp_generate_t4_rto_event,
sctp_generate_t5_shutdown_guard_event,
sctp_generate_heartbeat_event,
sctp_generate_sack_event,
sctp_generate_autoclose_event,
};
/* RFC 2960 8.2 Path Failure Detection
*
* When its peer endpoint is multi-homed, an endpoint should keep a
* error counter for each of the destination transport addresses of the
* peer endpoint.
*
* Each time the T3-rtx timer expires on any address, or when a
* HEARTBEAT sent to an idle address is not acknowledged within a RTO,
* the error counter of that destination address will be incremented.
* When the value in the error counter exceeds the protocol parameter
* 'Path.Max.Retrans' of that destination address, the endpoint should
* mark the destination transport address as inactive, and a
* notification SHOULD be sent to the upper layer.
*
*/
static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
struct sctp_transport *transport)
{
/* The check for association's overall error counter exceeding the
* threshold is done in the state function.
*/
asoc->overall_error_count++;
if (transport->state != SCTP_INACTIVE &&
(transport->error_count++ >= transport->max_retrans)) {
SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
" transport IP: port:%d failed.\n",
asoc,
(&transport->ipaddr),
transport->ipaddr.v4.sin_port);
sctp_assoc_control_transport(asoc, transport,
SCTP_TRANSPORT_DOWN,
SCTP_FAILED_THRESHOLD);
}
/* E2) For the destination address for which the timer
* expires, set RTO <- RTO * 2 ("back off the timer"). The
* maximum value discussed in rule C7 above (RTO.max) may be
* used to provide an upper bound to this doubling operation.
*/
transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
}
/* Worker routine to handle INIT command failure. */
static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
struct sctp_association *asoc,
unsigned error)
{
struct sctp_ulpevent *event;
event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
(__u16)error, 0, 0,
GFP_ATOMIC);
if (event)
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(event));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_CLOSED));
/* SEND_FAILED sent later when cleaning up the association. */
asoc->outqueue.error = error;
sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
}
/* Worker routine to handle SCTP_CMD_ASSOC_FAILED. */
static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
struct sctp_association *asoc,
sctp_event_t event_type,
sctp_subtype_t subtype,
struct sctp_chunk *chunk,
unsigned error)
{
struct sctp_ulpevent *event;
/* Cancel any partial delivery in progress. */
sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
(__u16)error, 0, 0,
GFP_ATOMIC);
if (event)
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(event));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_CLOSED));
/* Set sk_err to ECONNRESET on a 1-1 style socket. */
if (!sctp_style(asoc->base.sk, UDP))
asoc->base.sk->sk_err = ECONNRESET;
/* SEND_FAILED sent later when cleaning up the association. */
asoc->outqueue.error = error;
sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
}
/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
* inside the cookie. In reality, this is only used for INIT-ACK processing
* since all other cases use "temporary" associations and can do all
* their work in statefuns directly.
*/
static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
struct sctp_association *asoc,
struct sctp_chunk *chunk,
sctp_init_chunk_t *peer_init,
unsigned int __nocast gfp)
{
int error;
/* We only process the init as a sideeffect in a single
* case. This is when we process the INIT-ACK. If we
* fail during INIT processing (due to malloc problems),
* just return the error and stop processing the stack.
*/
if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
sctp_source(chunk), peer_init, gfp))
error = -ENOMEM;
else
error = 0;
return error;
}
/* Helper function to break out starting up of heartbeat timers. */
static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc)
{
struct sctp_transport *t;
struct list_head *pos;
/* Start a heartbeat timer for each transport on the association.
* hold a reference on the transport to make sure none of
* the needed data structures go away.
*/
list_for_each(pos, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport, transports);
if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
sctp_transport_hold(t);
}
}
static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc)
{
struct sctp_transport *t;
struct list_head *pos;
/* Stop all heartbeat timers. */
list_for_each(pos, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport, transports);
if (del_timer(&t->hb_timer))
sctp_transport_put(t);
}
}
/* Helper function to stop any pending T3-RTX timers */
static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc)
{
struct sctp_transport *t;
struct list_head *pos;
list_for_each(pos, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport, transports);
if (timer_pending(&t->T3_rtx_timer) &&
del_timer(&t->T3_rtx_timer)) {
sctp_transport_put(t);
}
}
}
/* Helper function to update the heartbeat timer. */
static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_transport *t)
{
/* Update the heartbeat timer. */
if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
sctp_transport_hold(t);
}
/* Helper function to handle the reception of an HEARTBEAT ACK. */
static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_transport *t,
struct sctp_chunk *chunk)
{
sctp_sender_hb_info_t *hbinfo;
/* 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.
* The association's overall error count is also cleared.
*/
t->error_count = 0;
t->asoc->overall_error_count = 0;
/* Mark the destination transport address as active if it is not so
* marked.
*/
if (t->state == SCTP_INACTIVE)
sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
SCTP_HEARTBEAT_SUCCESS);
/* 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.
*/
hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
}
/* Helper function to do a transport reset at the expiry of the hearbeat
* timer.
*/
static void sctp_cmd_transport_reset(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_transport *t)
{
sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
/* Mark one strike against a transport. */
sctp_do_8_2_transport_strike(asoc, t);
}
/* Helper function to process the process SACK command. */
static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_sackhdr *sackh)
{
int err;
if (sctp_outq_sack(&asoc->outqueue, sackh)) {
/* There are no more TSNs awaiting SACK. */
err = sctp_do_sm(SCTP_EVENT_T_OTHER,
SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
asoc->state, asoc->ep, asoc, NULL,
GFP_ATOMIC);
} else {
/* Windows may have opened, so we need
* to check if we have DATA to transmit
*/
err = sctp_outq_flush(&asoc->outqueue, 0);
}
return err;
}
/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
* the transport for a shutdown chunk.
*/
static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_chunk *chunk)
{
struct sctp_transport *t;
t = sctp_assoc_choose_shutdown_transport(asoc);
asoc->shutdown_last_sent_to = t;
asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
chunk->transport = t;
}
/* Helper function to change the state of an association. */
static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
sctp_state_t state)
{
struct sock *sk = asoc->base.sk;
asoc->state = state;
SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
asoc, sctp_state_tbl[state]);
if (sctp_style(sk, TCP)) {
/* Change the sk->sk_state of a TCP-style socket that has
* sucessfully completed a connect() call.
*/
if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
sk->sk_state = SCTP_SS_ESTABLISHED;
/* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
sctp_sstate(sk, ESTABLISHED))
sk->sk_shutdown |= RCV_SHUTDOWN;
}
if (sctp_state(asoc, COOKIE_WAIT)) {
/* Reset init timeouts since they may have been
* increased due to timer expirations.
*/
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
asoc->ep->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT];
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
asoc->ep->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE];
}
if (sctp_state(asoc, ESTABLISHED) ||
sctp_state(asoc, CLOSED) ||
sctp_state(asoc, SHUTDOWN_RECEIVED)) {
/* Wake up any processes waiting in the asoc's wait queue in
* sctp_wait_for_connect() or sctp_wait_for_sndbuf().
*/
if (waitqueue_active(&asoc->wait))
wake_up_interruptible(&asoc->wait);
/* Wake up any processes waiting in the sk's sleep queue of
* a TCP-style or UDP-style peeled-off socket in
* sctp_wait_for_accept() or sctp_wait_for_packet().
* For a UDP-style socket, the waiters are woken up by the
* notifications.
*/
if (!sctp_style(sk, UDP))
sk->sk_state_change(sk);
}
}
/* Helper function to delete an association. */
static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc)
{
struct sock *sk = asoc->base.sk;
/* If it is a non-temporary association belonging to a TCP-style
* listening socket that is not closed, do not free it so that accept()
* can pick it up later.
*/
if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
(!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
return;
sctp_unhash_established(asoc);
sctp_association_free(asoc);
}
/*
* ADDIP Section 4.1 ASCONF Chunk Procedures
* A4) Start a T-4 RTO timer, using the RTO value of the selected
* destination address (we use active path instead of primary path just
* because primary path may be inactive.
*/
static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_chunk *chunk)
{
struct sctp_transport *t;
t = asoc->peer.active_path;
asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
chunk->transport = t;
}
/* Process an incoming Operation Error Chunk. */
static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_chunk *chunk)
{
struct sctp_operr_chunk *operr_chunk;
struct sctp_errhdr *err_hdr;
operr_chunk = (struct sctp_operr_chunk *)chunk->chunk_hdr;
err_hdr = &operr_chunk->err_hdr;
switch (err_hdr->cause) {
case SCTP_ERROR_UNKNOWN_CHUNK:
{
struct sctp_chunkhdr *unk_chunk_hdr;
unk_chunk_hdr = (struct sctp_chunkhdr *)err_hdr->variable;
switch (unk_chunk_hdr->type) {
/* ADDIP 4.1 A9) If the peer responds to an ASCONF with an
* ERROR chunk reporting that it did not recognized the ASCONF
* chunk type, the sender of the ASCONF MUST NOT send any
* further ASCONF chunks and MUST stop its T-4 timer.
*/
case SCTP_CID_ASCONF:
asoc->peer.asconf_capable = 0;
sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
break;
default:
break;
}
break;
}
default:
break;
}
}
/* Process variable FWDTSN chunk information. */
static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
struct sctp_chunk *chunk)
{
struct sctp_fwdtsn_skip *skip;
/* Walk through all the skipped SSNs */
sctp_walk_fwdtsn(skip, chunk) {
sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
}
return;
}
/* Helper function to remove the association non-primary peer
* transports.
*/
static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
{
struct sctp_transport *t;
struct list_head *pos;
struct list_head *temp;
list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport, transports);
if (!sctp_cmp_addr_exact(&t->ipaddr,
&asoc->peer.primary_addr)) {
sctp_assoc_del_peer(asoc, &t->ipaddr);
}
}
return;
}
/* These three macros allow us to pull the debugging code out of the
* main flow of sctp_do_sm() to keep attention focused on the real
* functionality there.
*/
#define DEBUG_PRE \
SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
"ep %p, %s, %s, asoc %p[%s], %s\n", \
ep, sctp_evttype_tbl[event_type], \
(*debug_fn)(subtype), asoc, \
sctp_state_tbl[state], state_fn->name)
#define DEBUG_POST \
SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
"asoc %p, status: %s\n", \
asoc, sctp_status_tbl[status])
#define DEBUG_POST_SFX \
SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
error, asoc, \
sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
/*
* This is the master state machine processing function.
*
* If you want to understand all of lksctp, this is a
* good place to start.
*/
int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
sctp_state_t state,
struct sctp_endpoint *ep,
struct sctp_association *asoc,
void *event_arg,
unsigned int __nocast gfp)
{
sctp_cmd_seq_t commands;
const sctp_sm_table_entry_t *state_fn;
sctp_disposition_t status;
int error = 0;
typedef const char *(printfn_t)(sctp_subtype_t);
static printfn_t *table[] = {
NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
};
printfn_t *debug_fn __attribute__ ((unused)) = table[event_type];
/* Look up the state function, run it, and then process the
* side effects. These three steps are the heart of lksctp.
*/
state_fn = sctp_sm_lookup_event(event_type, state, subtype);
sctp_init_cmd_seq(&commands);
DEBUG_PRE;
status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
DEBUG_POST;
error = sctp_side_effects(event_type, subtype, state,
ep, asoc, event_arg, status,
&commands, gfp);
DEBUG_POST_SFX;
return error;
}
#undef DEBUG_PRE
#undef DEBUG_POST
/*****************************************************************
* This the master state function side effect processing function.
*****************************************************************/
static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
sctp_state_t state,
struct sctp_endpoint *ep,
struct sctp_association *asoc,
void *event_arg,
sctp_disposition_t status,
sctp_cmd_seq_t *commands,
unsigned int __nocast gfp)
{
int error;
/* FIXME - Most of the dispositions left today would be categorized
* as "exceptional" dispositions. For those dispositions, it
* may not be proper to run through any of the commands at all.
* For example, the command interpreter might be run only with
* disposition SCTP_DISPOSITION_CONSUME.
*/
if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
ep, asoc,
event_arg, status,
commands, gfp)))
goto bail;
switch (status) {
case SCTP_DISPOSITION_DISCARD:
SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
"event_type %d, event_id %d\n",
state, event_type, subtype.chunk);
break;
case SCTP_DISPOSITION_NOMEM:
/* We ran out of memory, so we need to discard this
* packet.
*/
/* BUG--we should now recover some memory, probably by
* reneging...
*/
error = -ENOMEM;
break;
case SCTP_DISPOSITION_DELETE_TCB:
/* This should now be a command. */
break;
case SCTP_DISPOSITION_CONSUME:
case SCTP_DISPOSITION_ABORT:
/*
* We should no longer have much work to do here as the
* real work has been done as explicit commands above.
*/
break;
case SCTP_DISPOSITION_VIOLATION:
printk(KERN_ERR "sctp protocol violation state %d "
"chunkid %d\n", state, subtype.chunk);
break;
case SCTP_DISPOSITION_NOT_IMPL:
printk(KERN_WARNING "sctp unimplemented feature in state %d, "
"event_type %d, event_id %d\n",
state, event_type, subtype.chunk);
break;
case SCTP_DISPOSITION_BUG:
printk(KERN_ERR "sctp bug in state %d, "
"event_type %d, event_id %d\n",
state, event_type, subtype.chunk);
BUG();
break;
default:
printk(KERN_ERR "sctp impossible disposition %d "
"in state %d, event_type %d, event_id %d\n",
status, state, event_type, subtype.chunk);
BUG();
break;
};
bail:
return error;
}
/********************************************************************
* 2nd Level Abstractions
********************************************************************/
/* This is the side-effect interpreter. */
static int sctp_cmd_interpreter(sctp_event_t event_type,
sctp_subtype_t subtype,
sctp_state_t state,
struct sctp_endpoint *ep,
struct sctp_association *asoc,
void *event_arg,
sctp_disposition_t status,
sctp_cmd_seq_t *commands,
unsigned int __nocast gfp)
{
int error = 0;
int force;
sctp_cmd_t *cmd;
struct sctp_chunk *new_obj;
struct sctp_chunk *chunk = NULL;
struct sctp_packet *packet;
struct list_head *pos;
struct timer_list *timer;
unsigned long timeout;
struct sctp_transport *t;
struct sctp_sackhdr sackh;
int local_cork = 0;
if (SCTP_EVENT_T_TIMEOUT != event_type)
chunk = (struct sctp_chunk *) event_arg;
/* Note: This whole file is a huge candidate for rework.
* For example, each command could either have its own handler, so
* the loop would look like:
* while (cmds)
* cmd->handle(x, y, z)
* --jgrimm
*/
while (NULL != (cmd = sctp_next_cmd(commands))) {
switch (cmd->verb) {
case SCTP_CMD_NOP:
/* Do nothing. */
break;
case SCTP_CMD_NEW_ASOC:
/* Register a new association. */
if (local_cork) {
sctp_outq_uncork(&asoc->outqueue);
local_cork = 0;
}
asoc = cmd->obj.ptr;
/* Register with the endpoint. */
sctp_endpoint_add_asoc(ep, asoc);
sctp_hash_established(asoc);
break;
case SCTP_CMD_UPDATE_ASSOC:
sctp_assoc_update(asoc, cmd->obj.ptr);
break;
case SCTP_CMD_PURGE_OUTQUEUE:
sctp_outq_teardown(&asoc->outqueue);
break;
case SCTP_CMD_DELETE_TCB:
if (local_cork) {
sctp_outq_uncork(&asoc->outqueue);
local_cork = 0;
}
/* Delete the current association. */
sctp_cmd_delete_tcb(commands, asoc);
asoc = NULL;
break;
case SCTP_CMD_NEW_STATE:
/* Enter a new state. */
sctp_cmd_new_state(commands, asoc, cmd->obj.state);
break;
case SCTP_CMD_REPORT_TSN:
/* Record the arrival of a TSN. */
sctp_tsnmap_mark(&asoc->peer.tsn_map, cmd->obj.u32);
break;
case SCTP_CMD_REPORT_FWDTSN:
/* Move the Cumulattive TSN Ack ahead. */
sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
/* Abort any in progress partial delivery. */
sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
break;
case SCTP_CMD_PROCESS_FWDTSN:
sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
break;
case SCTP_CMD_GEN_SACK:
/* Generate a Selective ACK.
* The argument tells us whether to just count
* the packet and MAYBE generate a SACK, or
* force a SACK out.
*/
force = cmd->obj.i32;
error = sctp_gen_sack(asoc, force, commands);
break;
case SCTP_CMD_PROCESS_SACK:
/* Process an inbound SACK. */
error = sctp_cmd_process_sack(commands, asoc,
cmd->obj.ptr);
break;
case SCTP_CMD_GEN_INIT_ACK:
/* Generate an INIT ACK chunk. */
new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
0);
if (!new_obj)
goto nomem;
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
SCTP_CHUNK(new_obj));
break;
case SCTP_CMD_PEER_INIT:
/* Process a unified INIT from the peer.
* Note: Only used during INIT-ACK processing. If
* there is an error just return to the outter
* layer which will bail.
*/
error = sctp_cmd_process_init(commands, asoc, chunk,
cmd->obj.ptr, gfp);
break;
case SCTP_CMD_GEN_COOKIE_ECHO:
/* Generate a COOKIE ECHO chunk. */
new_obj = sctp_make_cookie_echo(asoc, chunk);
if (!new_obj) {
if (cmd->obj.ptr)
sctp_chunk_free(cmd->obj.ptr);
goto nomem;
}
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
SCTP_CHUNK(new_obj));
/* If there is an ERROR chunk to be sent along with
* the COOKIE_ECHO, send it, too.
*/
if (cmd->obj.ptr)
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
SCTP_CHUNK(cmd->obj.ptr));
/* FIXME - Eventually come up with a cleaner way to
* enabling COOKIE-ECHO + DATA bundling during
* multihoming stale cookie scenarios, the following
* command plays with asoc->peer.retran_path to
* avoid the problem of sending the COOKIE-ECHO and
* DATA in different paths, which could result
* in the association being ABORTed if the DATA chunk
* is processed first by the server. Checking the
* init error counter simply causes this command
* to be executed only during failed attempts of
* association establishment.
*/
if ((asoc->peer.retran_path !=
asoc->peer.primary_path) &&
(asoc->init_err_counter > 0)) {
sctp_add_cmd_sf(commands,
SCTP_CMD_FORCE_PRIM_RETRAN,
SCTP_NULL());
}
break;
case SCTP_CMD_GEN_SHUTDOWN:
/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
* Reset error counts.
*/
asoc->overall_error_count = 0;
/* Generate a SHUTDOWN chunk. */
new_obj = sctp_make_shutdown(asoc, chunk);
if (!new_obj)
goto nomem;
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
SCTP_CHUNK(new_obj));
break;
case SCTP_CMD_CHUNK_ULP:
/* Send a chunk to the sockets layer. */
SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
"chunk_up:", cmd->obj.ptr,
"ulpq:", &asoc->ulpq);
sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
GFP_ATOMIC);
break;
case SCTP_CMD_EVENT_ULP:
/* Send a notification to the sockets layer. */
SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
"event_up:",cmd->obj.ptr,
"ulpq:",&asoc->ulpq);
sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
break;
case SCTP_CMD_REPLY:
/* If an caller has not already corked, do cork. */
if (!asoc->outqueue.cork) {
sctp_outq_cork(&asoc->outqueue);
local_cork = 1;
}
/* Send a chunk to our peer. */
error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
break;
case SCTP_CMD_SEND_PKT:
/* Send a full packet to our peer. */
packet = cmd->obj.ptr;
sctp_packet_transmit(packet);
sctp_ootb_pkt_free(packet);
break;
case SCTP_CMD_RETRAN:
/* Mark a transport for retransmission. */
sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
SCTP_RTXR_T3_RTX);
break;
case SCTP_CMD_TRANSMIT:
/* Kick start transmission. */
error = sctp_outq_uncork(&asoc->outqueue);
local_cork = 0;
break;
case SCTP_CMD_ECN_CE:
/* Do delayed CE processing. */
sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
break;
case SCTP_CMD_ECN_ECNE:
/* Do delayed ECNE processing. */
new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
chunk);
if (new_obj)
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
SCTP_CHUNK(new_obj));
break;
case SCTP_CMD_ECN_CWR:
/* Do delayed CWR processing. */
sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
break;
case SCTP_CMD_SETUP_T2:
sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
break;
case SCTP_CMD_TIMER_START:
timer = &asoc->timers[cmd->obj.to];
timeout = asoc->timeouts[cmd->obj.to];
if (!timeout)
BUG();
timer->expires = jiffies + timeout;
sctp_association_hold(asoc);
add_timer(timer);
break;
case SCTP_CMD_TIMER_RESTART:
timer = &asoc->timers[cmd->obj.to];
timeout = asoc->timeouts[cmd->obj.to];
if (!mod_timer(timer, jiffies + timeout))
sctp_association_hold(asoc);
break;
case SCTP_CMD_TIMER_STOP:
timer = &asoc->timers[cmd->obj.to];
if (timer_pending(timer) && del_timer(timer))
sctp_association_put(asoc);
break;
case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
chunk = cmd->obj.ptr;
t = sctp_assoc_choose_init_transport(asoc);
asoc->init_last_sent_to = t;
chunk->transport = t;
t->init_sent_count++;
break;
case SCTP_CMD_INIT_RESTART:
/* Do the needed accounting and updates
* associated with restarting an initialization
* timer. Only multiply the timeout by two if
* all transports have been tried at the current
* timeout.
*/
t = asoc->init_last_sent_to;
asoc->init_err_counter++;
if (t->init_sent_count > (asoc->init_cycle + 1)) {
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] *= 2;
if (asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] >
asoc->max_init_timeo) {
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
asoc->max_init_timeo;
}
asoc->init_cycle++;
SCTP_DEBUG_PRINTK(
"T1 INIT Timeout adjustment"
" init_err_counter: %d"
" cycle: %d"
" timeout: %d\n",
asoc->init_err_counter,
asoc->init_cycle,
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT]);
}
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
break;
case SCTP_CMD_COOKIEECHO_RESTART:
/* Do the needed accounting and updates
* associated with restarting an initialization
* timer. Only multiply the timeout by two if
* all transports have been tried at the current
* timeout.
*/
asoc->init_err_counter++;
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] *= 2;
if (asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] >
asoc->max_init_timeo) {
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
asoc->max_init_timeo;
}
SCTP_DEBUG_PRINTK(
"T1 COOKIE Timeout adjustment"
" init_err_counter: %d"
" timeout: %d\n",
asoc->init_err_counter,
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
/* If we've sent any data bundled with
* COOKIE-ECHO we need to resend.
*/
list_for_each(pos, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport,
transports);
sctp_retransmit_mark(&asoc->outqueue, t, 0);
}
sctp_add_cmd_sf(commands,
SCTP_CMD_TIMER_RESTART,
SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
break;
case SCTP_CMD_INIT_FAILED:
sctp_cmd_init_failed(commands, asoc, cmd->obj.u32);
break;
case SCTP_CMD_ASSOC_FAILED:
sctp_cmd_assoc_failed(commands, asoc, event_type,
subtype, chunk, cmd->obj.u32);
break;
case SCTP_CMD_INIT_COUNTER_INC:
asoc->init_err_counter++;
break;
case SCTP_CMD_INIT_COUNTER_RESET:
asoc->init_err_counter = 0;
asoc->init_cycle = 0;
break;
case SCTP_CMD_REPORT_DUP:
sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
cmd->obj.u32);
break;
case SCTP_CMD_REPORT_BAD_TAG:
SCTP_DEBUG_PRINTK("vtag mismatch!\n");
break;
case SCTP_CMD_STRIKE:
/* Mark one strike against a transport. */
sctp_do_8_2_transport_strike(asoc, cmd->obj.transport);
break;
case SCTP_CMD_TRANSPORT_RESET:
t = cmd->obj.transport;
sctp_cmd_transport_reset(commands, asoc, t);
break;
case SCTP_CMD_TRANSPORT_ON:
t = cmd->obj.transport;
sctp_cmd_transport_on(commands, asoc, t, chunk);
break;
case SCTP_CMD_HB_TIMERS_START:
sctp_cmd_hb_timers_start(commands, asoc);
break;
case SCTP_CMD_HB_TIMER_UPDATE:
t = cmd->obj.transport;
sctp_cmd_hb_timer_update(commands, asoc, t);
break;
case SCTP_CMD_HB_TIMERS_STOP:
sctp_cmd_hb_timers_stop(commands, asoc);
break;
case SCTP_CMD_REPORT_ERROR:
error = cmd->obj.error;
break;
case SCTP_CMD_PROCESS_CTSN:
/* Dummy up a SACK for processing. */
sackh.cum_tsn_ack = cmd->obj.u32;
sackh.a_rwnd = 0;
sackh.num_gap_ack_blocks = 0;
sackh.num_dup_tsns = 0;
sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
SCTP_SACKH(&sackh));
break;
case SCTP_CMD_DISCARD_PACKET:
/* We need to discard the whole packet. */
chunk->pdiscard = 1;
break;
case SCTP_CMD_RTO_PENDING:
t = cmd->obj.transport;
t->rto_pending = 1;
break;
case SCTP_CMD_PART_DELIVER:
sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
GFP_ATOMIC);
break;
case SCTP_CMD_RENEGE:
sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
GFP_ATOMIC);
break;
case SCTP_CMD_SETUP_T4:
sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
break;
case SCTP_CMD_PROCESS_OPERR:
sctp_cmd_process_operr(commands, asoc, chunk);
break;
case SCTP_CMD_CLEAR_INIT_TAG:
asoc->peer.i.init_tag = 0;
break;
case SCTP_CMD_DEL_NON_PRIMARY:
sctp_cmd_del_non_primary(asoc);
break;
case SCTP_CMD_T3_RTX_TIMERS_STOP:
sctp_cmd_t3_rtx_timers_stop(commands, asoc);
break;
case SCTP_CMD_FORCE_PRIM_RETRAN:
t = asoc->peer.retran_path;
asoc->peer.retran_path = asoc->peer.primary_path;
error = sctp_outq_uncork(&asoc->outqueue);
local_cork = 0;
asoc->peer.retran_path = t;
break;
default:
printk(KERN_WARNING "Impossible command: %u, %p\n",
cmd->verb, cmd->obj.ptr);
break;
};
if (error)
break;
}
out:
if (local_cork)
sctp_outq_uncork(&asoc->outqueue);
return error;
nomem:
error = -ENOMEM;
goto out;
}
