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dd0fc66fb3
linux-next/net/sctp/sm_sideeffect.c
Al Viro dd0fc66fb3 [PATCH] gfp flags annotations - part 1 
- added typedef unsigned int __nocast gfp_t;

 - replaced __nocast uses for gfp flags with gfp_t - it gives exactly
   the same warnings as far as sparse is concerned, doesn't change
   generated code (from gcc point of view we replaced unsigned int with
   typedef) and documents what's going on far better.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 15:00:57 -07:00

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/* 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,
gfp_t 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,
gfp_t 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,
gfp_t 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,
gfp_t 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,
gfp_t 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,
gfp_t 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;
}
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