linux/include/net/sctp/command.h
Thomas Graf f8d9605243 sctp: Enforce retransmission limit during shutdown
When initiating a graceful shutdown while having data chunks
on the retransmission queue with a peer which is in zero
window mode the shutdown is never completed because the
retransmission error count is reset periodically by the
following two rules:

 - Do not timeout association while doing zero window probe.
 - Reset overall error count when a heartbeat request has
   been acknowledged.

The graceful shutdown will wait for all outstanding TSN to
be acknowledged before sending the SHUTDOWN request. This
never happens due to the peer's zero window not acknowledging
the continuously retransmitted data chunks. Although the
error counter is incremented for each failed retransmission,
the receiving of the SACK announcing the zero window clears
the error count again immediately. Also heartbeat requests
continue to be sent periodically. The peer acknowledges these
requests causing the error counter to be reset as well.

This patch changes behaviour to only reset the overall error
counter for the above rules while not in shutdown. After
reaching the maximum number of retransmission attempts, the
T5 shutdown guard timer is scheduled to give the receiver
some additional time to recover. The timer is stopped as soon
as the receiver acknowledges any data.

The issue can be easily reproduced by establishing a sctp
association over the loopback device, constantly queueing
data at the sender while not reading any at the receiver.
Wait for the window to reach zero, then initiate a shutdown
by killing both processes simultaneously. The association
will never be freed and the chunks on the retransmission
queue will be retransmitted indefinitely.

Signed-off-by: Thomas Graf <tgraf@infradead.org>
Acked-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-07-07 14:08:44 -07:00

224 lines
8.8 KiB
C

/* SCTP kernel Implementation
* (C) Copyright IBM Corp. 2001, 2004
* Copyright (C) 1999-2001 Cisco, Motorola
*
* This file is part of the SCTP kernel implementation
*
* These are the definitions needed for the command object.
*
* 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, 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 one of the
* following email addresses:
*
* La Monte H.P. Yarroll <piggy@acm.org>
* Karl Knutson <karl@athena.chicago.il.us>
* Ardelle Fan <ardelle.fan@intel.com>
* Sridhar Samudrala <sri@us.ibm.com>
*
* Any bugs reported given to us we will try to fix... any fixes shared will
* be incorporated into the next SCTP release.
*/
#ifndef __net_sctp_command_h__
#define __net_sctp_command_h__
#include <net/sctp/constants.h>
#include <net/sctp/structs.h>
typedef enum {
SCTP_CMD_NOP = 0, /* Do nothing. */
SCTP_CMD_NEW_ASOC, /* Register a new association. */
SCTP_CMD_DELETE_TCB, /* Delete the current association. */
SCTP_CMD_NEW_STATE, /* Enter a new state. */
SCTP_CMD_REPORT_TSN, /* Record the arrival of a TSN. */
SCTP_CMD_GEN_SACK, /* Send a Selective ACK (maybe). */
SCTP_CMD_PROCESS_SACK, /* Process an inbound SACK. */
SCTP_CMD_GEN_INIT_ACK, /* Generate an INIT ACK chunk. */
SCTP_CMD_PEER_INIT, /* Process a INIT from the peer. */
SCTP_CMD_GEN_COOKIE_ECHO, /* Generate a COOKIE ECHO chunk. */
SCTP_CMD_CHUNK_ULP, /* Send a chunk to the sockets layer. */
SCTP_CMD_EVENT_ULP, /* Send a notification to the sockets layer. */
SCTP_CMD_REPLY, /* Send a chunk to our peer. */
SCTP_CMD_SEND_PKT, /* Send a full packet to our peer. */
SCTP_CMD_RETRAN, /* Mark a transport for retransmission. */
SCTP_CMD_ECN_CE, /* Do delayed CE processing. */
SCTP_CMD_ECN_ECNE, /* Do delayed ECNE processing. */
SCTP_CMD_ECN_CWR, /* Do delayed CWR processing. */
SCTP_CMD_TIMER_START, /* Start a timer. */
SCTP_CMD_TIMER_START_ONCE, /* Start a timer once */
SCTP_CMD_TIMER_RESTART, /* Restart a timer. */
SCTP_CMD_TIMER_STOP, /* Stop a timer. */
SCTP_CMD_INIT_CHOOSE_TRANSPORT, /* Choose transport for an INIT. */
SCTP_CMD_INIT_COUNTER_RESET, /* Reset init counter. */
SCTP_CMD_INIT_COUNTER_INC, /* Increment init counter. */
SCTP_CMD_INIT_RESTART, /* High level, do init timer work. */
SCTP_CMD_COOKIEECHO_RESTART, /* High level, do cookie-echo timer work. */
SCTP_CMD_INIT_FAILED, /* High level, do init failure work. */
SCTP_CMD_REPORT_DUP, /* Report a duplicate TSN. */
SCTP_CMD_STRIKE, /* Mark a strike against a transport. */
SCTP_CMD_HB_TIMERS_START, /* Start the heartbeat timers. */
SCTP_CMD_HB_TIMER_UPDATE, /* Update a heartbeat timers. */
SCTP_CMD_HB_TIMERS_STOP, /* Stop the heartbeat timers. */
SCTP_CMD_TRANSPORT_HB_SENT, /* Reset the status of a transport. */
SCTP_CMD_TRANSPORT_IDLE, /* Do manipulations on idle transport */
SCTP_CMD_TRANSPORT_ON, /* Mark the transport as active. */
SCTP_CMD_REPORT_ERROR, /* Pass this error back out of the sm. */
SCTP_CMD_REPORT_BAD_TAG, /* Verification tags didn't match. */
SCTP_CMD_PROCESS_CTSN, /* Sideeffect from shutdown. */
SCTP_CMD_ASSOC_FAILED, /* Handle association failure. */
SCTP_CMD_DISCARD_PACKET, /* Discard the whole packet. */
SCTP_CMD_GEN_SHUTDOWN, /* Generate a SHUTDOWN chunk. */
SCTP_CMD_UPDATE_ASSOC, /* Update association information. */
SCTP_CMD_PURGE_OUTQUEUE, /* Purge all data waiting to be sent. */
SCTP_CMD_SETUP_T2, /* Hi-level, setup T2-shutdown parms. */
SCTP_CMD_RTO_PENDING, /* Set transport's rto_pending. */
SCTP_CMD_PART_DELIVER, /* Partial data delivery considerations. */
SCTP_CMD_RENEGE, /* Renege data on an association. */
SCTP_CMD_SETUP_T4, /* ADDIP, setup T4 RTO timer parms. */
SCTP_CMD_PROCESS_OPERR, /* Process an ERROR chunk. */
SCTP_CMD_REPORT_FWDTSN, /* Report new cumulative TSN Ack. */
SCTP_CMD_PROCESS_FWDTSN, /* Skips were reported, so process further. */
SCTP_CMD_CLEAR_INIT_TAG, /* Clears association peer's inittag. */
SCTP_CMD_DEL_NON_PRIMARY, /* Removes non-primary peer transports. */
SCTP_CMD_T3_RTX_TIMERS_STOP, /* Stops T3-rtx pending timers */
SCTP_CMD_FORCE_PRIM_RETRAN, /* Forces retrans. over primary path. */
SCTP_CMD_SET_SK_ERR, /* Set sk_err */
SCTP_CMD_ASSOC_CHANGE, /* generate and send assoc_change event */
SCTP_CMD_ADAPTATION_IND, /* generate and send adaptation event */
SCTP_CMD_ASSOC_SHKEY, /* generate the association shared keys */
SCTP_CMD_T1_RETRAN, /* Mark for retransmission after T1 timeout */
SCTP_CMD_UPDATE_INITTAG, /* Update peer inittag */
SCTP_CMD_SEND_MSG, /* Send the whole use message */
SCTP_CMD_SEND_NEXT_ASCONF, /* Send the next ASCONF after ACK */
SCTP_CMD_PURGE_ASCONF_QUEUE, /* Purge all asconf queues.*/
SCTP_CMD_LAST
} sctp_verb_t;
/* How many commands can you put in an sctp_cmd_seq_t?
* This is a rather arbitrary number, ideally derived from a careful
* analysis of the state functions, but in reality just taken from
* thin air in the hopes othat we don't trigger a kernel panic.
*/
#define SCTP_MAX_NUM_COMMANDS 14
typedef union {
__s32 i32;
__u32 u32;
__be32 be32;
__u16 u16;
__u8 u8;
int error;
__be16 err;
sctp_state_t state;
sctp_event_timeout_t to;
unsigned long zero;
void *ptr;
struct sctp_chunk *chunk;
struct sctp_association *asoc;
struct sctp_transport *transport;
struct sctp_bind_addr *bp;
sctp_init_chunk_t *init;
struct sctp_ulpevent *ulpevent;
struct sctp_packet *packet;
sctp_sackhdr_t *sackh;
struct sctp_datamsg *msg;
} sctp_arg_t;
/* We are simulating ML type constructors here.
*
* SCTP_ARG_CONSTRUCTOR(NAME, TYPE, ELT) builds a function called
* SCTP_NAME() which takes an argument of type TYPE and returns an
* sctp_arg_t. It does this by inserting the sole argument into the
* ELT union element of a local sctp_arg_t.
*
* E.g., SCTP_ARG_CONSTRUCTOR(I32, __s32, i32) builds SCTP_I32(arg),
* which takes an __s32 and returns a sctp_arg_t containing the
* __s32. So, after foo = SCTP_I32(arg), foo.i32 == arg.
*/
static inline sctp_arg_t SCTP_NULL(void)
{
sctp_arg_t retval; retval.ptr = NULL; return retval;
}
static inline sctp_arg_t SCTP_NOFORCE(void)
{
sctp_arg_t retval = {.zero = 0UL}; retval.i32 = 0; return retval;
}
static inline sctp_arg_t SCTP_FORCE(void)
{
sctp_arg_t retval = {.zero = 0UL}; retval.i32 = 1; return retval;
}
#define SCTP_ARG_CONSTRUCTOR(name, type, elt) \
static inline sctp_arg_t \
SCTP_## name (type arg) \
{ sctp_arg_t retval = {.zero = 0UL}; retval.elt = arg; return retval; }
SCTP_ARG_CONSTRUCTOR(I32, __s32, i32)
SCTP_ARG_CONSTRUCTOR(U32, __u32, u32)
SCTP_ARG_CONSTRUCTOR(BE32, __be32, be32)
SCTP_ARG_CONSTRUCTOR(U16, __u16, u16)
SCTP_ARG_CONSTRUCTOR(U8, __u8, u8)
SCTP_ARG_CONSTRUCTOR(ERROR, int, error)
SCTP_ARG_CONSTRUCTOR(PERR, __be16, err) /* protocol error */
SCTP_ARG_CONSTRUCTOR(STATE, sctp_state_t, state)
SCTP_ARG_CONSTRUCTOR(TO, sctp_event_timeout_t, to)
SCTP_ARG_CONSTRUCTOR(PTR, void *, ptr)
SCTP_ARG_CONSTRUCTOR(CHUNK, struct sctp_chunk *, chunk)
SCTP_ARG_CONSTRUCTOR(ASOC, struct sctp_association *, asoc)
SCTP_ARG_CONSTRUCTOR(TRANSPORT, struct sctp_transport *, transport)
SCTP_ARG_CONSTRUCTOR(BA, struct sctp_bind_addr *, bp)
SCTP_ARG_CONSTRUCTOR(PEER_INIT, sctp_init_chunk_t *, init)
SCTP_ARG_CONSTRUCTOR(ULPEVENT, struct sctp_ulpevent *, ulpevent)
SCTP_ARG_CONSTRUCTOR(PACKET, struct sctp_packet *, packet)
SCTP_ARG_CONSTRUCTOR(SACKH, sctp_sackhdr_t *, sackh)
SCTP_ARG_CONSTRUCTOR(DATAMSG, struct sctp_datamsg *, msg)
typedef struct {
sctp_arg_t obj;
sctp_verb_t verb;
} sctp_cmd_t;
typedef struct {
sctp_cmd_t cmds[SCTP_MAX_NUM_COMMANDS];
__u8 next_free_slot;
__u8 next_cmd;
} sctp_cmd_seq_t;
/* Initialize a block of memory as a command sequence.
* Return 0 if the initialization fails.
*/
int sctp_init_cmd_seq(sctp_cmd_seq_t *seq);
/* Add a command to an sctp_cmd_seq_t.
*
* Use the SCTP_* constructors defined by SCTP_ARG_CONSTRUCTOR() above
* to wrap data which goes in the obj argument.
*/
void sctp_add_cmd_sf(sctp_cmd_seq_t *seq, sctp_verb_t verb, sctp_arg_t obj);
/* Return the next command structure in an sctp_cmd_seq.
* Return NULL at the end of the sequence.
*/
sctp_cmd_t *sctp_next_cmd(sctp_cmd_seq_t *seq);
#endif /* __net_sctp_command_h__ */