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linux/include/net/sctp/command.h
Vlad Yasevich bdf6fa52f0 sctp: handle association restarts when the socket is closed. 
Currently association restarts do not take into consideration the
state of the socket.  When a restart happens, the current assocation
simply transitions into established state.  This creates a condition
where a remote system, through a the restart procedure, may create a
local association that is no way reachable by user.  The conditions
to trigger this are as follows:
  1) Remote does not acknoledge some data causing data to remain
     outstanding.
  2) Local application calls close() on the socket.  Since data
     is still outstanding, the association is placed in SHUTDOWN_PENDING
     state.  However, the socket is closed.
  3) The remote tries to create a new association, triggering a restart
     on the local system.  The association moves from SHUTDOWN_PENDING
     to ESTABLISHED.  At this point, it is no longer reachable by
     any socket on the local system.

This patch addresses the above situation by moving the newly ESTABLISHED
association into SHUTDOWN-SENT state and bundling a SHUTDOWN after
the COOKIE-ACK chunk.  This way, the restarted associate immidiately
enters the shutdown procedure and forces the termination of the
unreachable association.

Reported-by: David Laight <David.Laight@aculab.com>
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-06 00:21:45 -04:00

252 lines
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/* 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, 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>
* Ardelle Fan <ardelle.fan@intel.com>
* Sridhar Samudrala <sri@us.ibm.com>
*/
#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_SET_ASOC, /* Restore association context */
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 20
typedef union {
void *zero_all; /* Set to NULL to clear the entire union */
__s32 i32;
__u32 u32;
__be32 be32;
__u16 u16;
__u8 u8;
int error;
__be16 err;
sctp_state_t state;
sctp_event_timeout_t to;
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.
*/
#define SCTP_ARG_CONSTRUCTOR(name, type, elt) \
static inline sctp_arg_t \
SCTP_## name (type arg) \
{ sctp_arg_t retval;\
retval.zero_all = NULL;\
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(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)
static inline sctp_arg_t SCTP_FORCE(void)
{
return SCTP_I32(1);
}
static inline sctp_arg_t SCTP_NOFORCE(void)
{
return SCTP_I32(0);
}
static inline sctp_arg_t SCTP_NULL(void)
{
sctp_arg_t retval;
retval.zero_all = NULL;
return retval;
}
typedef struct {
sctp_arg_t obj;
sctp_verb_t verb;
} sctp_cmd_t;
typedef struct {
sctp_cmd_t cmds[SCTP_MAX_NUM_COMMANDS];
sctp_cmd_t *last_used_slot;
sctp_cmd_t *next_cmd;
} sctp_cmd_seq_t;
/* Initialize a block of memory as a command sequence.
* Return 0 if the initialization fails.
*/
static inline int sctp_init_cmd_seq(sctp_cmd_seq_t *seq)
{
/* cmds[] is filled backwards to simplify the overflow BUG() check */
seq->last_used_slot = seq->cmds + SCTP_MAX_NUM_COMMANDS;
seq->next_cmd = seq->last_used_slot;
return 1; /* We always succeed. */
}
/* 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.
*/
static inline void sctp_add_cmd_sf(sctp_cmd_seq_t *seq, sctp_verb_t verb,
sctp_arg_t obj)
{
sctp_cmd_t *cmd = seq->last_used_slot - 1;
BUG_ON(cmd < seq->cmds);
cmd->verb = verb;
cmd->obj = obj;
seq->last_used_slot = cmd;
}
/* Return the next command structure in an sctp_cmd_seq.
* Return NULL at the end of the sequence.
*/
static inline sctp_cmd_t *sctp_next_cmd(sctp_cmd_seq_t *seq)
{
if (seq->next_cmd <= seq->last_used_slot)
return NULL;
return --seq->next_cmd;
}
#endif /* __net_sctp_command_h__ */
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