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linux/include/net/sctp/command.h
Neil Horman b26ddd8130 sctp: Clean up type-punning in sctp_cmd_t union 
Lots of points in the sctp_cmd_interpreter function treat the sctp_cmd_t arg as
a void pointer, even though they are written as various other types.  Theres no
need for this as doing so just leads to possible type-punning issues that could
cause crashes, and if we remain type-consistent we can actually just remove the
void * member of the union entirely.

Change Notes:

v2)
	* Dropped chunk that modified SCTP_NULL to create a marker pattern
	 should anyone try to use a SCTP_NULL() assigned sctp_arg_t, Assigning
	 to .zero provides the same effect and should be faster, per Vlad Y.

v3)
	* Reverted part of V2, opting to use memset instead of .zero, so that
	 the entire union is initalized thus avoiding the i164 speculative load
	 problems previously encountered, per Dave M..  Also rewrote
	 SCTP_[NO]FORCE so as to use common infrastructure a little more

Signed-off-by: Neil Horman <nhorman@tuxdriver.com
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: linux-sctp@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-03 14:54:55 -04:00

232 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, 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_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 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;
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;\
memset(&retval, 0, sizeof(sctp_arg_t));\
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;
memset(&retval, 0, sizeof(sctp_arg_t));
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];
__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__ */
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