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1/* SCTP kernel Implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (C) 1999-2001 Cisco, Motorola
4 *
5 * This file is part of the SCTP kernel implementation
6 *
7 * These are the definitions needed for the command object.
8 *
9 * This SCTP implementation is free software;
10 * you can redistribute it and/or modify it under the terms of
11 * the GNU General Public License as published by
12 * the Free Software Foundation; either version 2, or (at your option)
13 * any later version.
14 *
15 * This SCTP implementation is distributed in the hope that it
16 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
17 * ************************
18 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19 * See the GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with GNU CC; see the file COPYING. If not, write to
23 * the Free Software Foundation, 59 Temple Place - Suite 330,
24 * Boston, MA 02111-1307, USA.
25 *
26 * Please send any bug reports or fixes you make to one of the
27 * following email addresses:
28 *
29 * La Monte H.P. Yarroll <piggy@acm.org>
30 * Karl Knutson <karl@athena.chicago.il.us>
31 * Ardelle Fan <ardelle.fan@intel.com>
32 * Sridhar Samudrala <sri@us.ibm.com>
33 *
34 * Any bugs reported given to us we will try to fix... any fixes shared will
35 * be incorporated into the next SCTP release.
36 */
37
38
39#ifndef __net_sctp_command_h__
40#define __net_sctp_command_h__
41
42#include <net/sctp/constants.h>
43#include <net/sctp/structs.h>
44
45
46typedef enum {
47 SCTP_CMD_NOP = 0, /* Do nothing. */
48 SCTP_CMD_NEW_ASOC, /* Register a new association. */
49 SCTP_CMD_DELETE_TCB, /* Delete the current association. */
50 SCTP_CMD_NEW_STATE, /* Enter a new state. */
51 SCTP_CMD_REPORT_TSN, /* Record the arrival of a TSN. */
52 SCTP_CMD_GEN_SACK, /* Send a Selective ACK (maybe). */
53 SCTP_CMD_PROCESS_SACK, /* Process an inbound SACK. */
54 SCTP_CMD_GEN_INIT_ACK, /* Generate an INIT ACK chunk. */
55 SCTP_CMD_PEER_INIT, /* Process a INIT from the peer. */
56 SCTP_CMD_GEN_COOKIE_ECHO, /* Generate a COOKIE ECHO chunk. */
57 SCTP_CMD_CHUNK_ULP, /* Send a chunk to the sockets layer. */
58 SCTP_CMD_EVENT_ULP, /* Send a notification to the sockets layer. */
59 SCTP_CMD_REPLY, /* Send a chunk to our peer. */
60 SCTP_CMD_SEND_PKT, /* Send a full packet to our peer. */
61 SCTP_CMD_RETRAN, /* Mark a transport for retransmission. */
62 SCTP_CMD_ECN_CE, /* Do delayed CE processing. */
63 SCTP_CMD_ECN_ECNE, /* Do delayed ECNE processing. */
64 SCTP_CMD_ECN_CWR, /* Do delayed CWR processing. */
65 SCTP_CMD_TIMER_START, /* Start a timer. */
66 SCTP_CMD_TIMER_START_ONCE, /* Start a timer once */
67 SCTP_CMD_TIMER_RESTART, /* Restart a timer. */
68 SCTP_CMD_TIMER_STOP, /* Stop a timer. */
69 SCTP_CMD_INIT_CHOOSE_TRANSPORT, /* Choose transport for an INIT. */
70 SCTP_CMD_INIT_COUNTER_RESET, /* Reset init counter. */
71 SCTP_CMD_INIT_COUNTER_INC, /* Increment init counter. */
72 SCTP_CMD_INIT_RESTART, /* High level, do init timer work. */
73 SCTP_CMD_COOKIEECHO_RESTART, /* High level, do cookie-echo timer work. */
74 SCTP_CMD_INIT_FAILED, /* High level, do init failure work. */
75 SCTP_CMD_REPORT_DUP, /* Report a duplicate TSN. */
76 SCTP_CMD_STRIKE, /* Mark a strike against a transport. */
77 SCTP_CMD_HB_TIMERS_START, /* Start the heartbeat timers. */
78 SCTP_CMD_HB_TIMER_UPDATE, /* Update a heartbeat timers. */
79 SCTP_CMD_HB_TIMERS_STOP, /* Stop the heartbeat timers. */
80 SCTP_CMD_TRANSPORT_HB_SENT, /* Reset the status of a transport. */
81 SCTP_CMD_TRANSPORT_IDLE, /* Do manipulations on idle transport */
82 SCTP_CMD_TRANSPORT_ON, /* Mark the transport as active. */
83 SCTP_CMD_REPORT_ERROR, /* Pass this error back out of the sm. */
84 SCTP_CMD_REPORT_BAD_TAG, /* Verification tags didn't match. */
85 SCTP_CMD_PROCESS_CTSN, /* Sideeffect from shutdown. */
86 SCTP_CMD_ASSOC_FAILED, /* Handle association failure. */
87 SCTP_CMD_DISCARD_PACKET, /* Discard the whole packet. */
88 SCTP_CMD_GEN_SHUTDOWN, /* Generate a SHUTDOWN chunk. */
89 SCTP_CMD_UPDATE_ASSOC, /* Update association information. */
90 SCTP_CMD_PURGE_OUTQUEUE, /* Purge all data waiting to be sent. */
91 SCTP_CMD_SETUP_T2, /* Hi-level, setup T2-shutdown parms. */
92 SCTP_CMD_RTO_PENDING, /* Set transport's rto_pending. */
93 SCTP_CMD_PART_DELIVER, /* Partial data delivery considerations. */
94 SCTP_CMD_RENEGE, /* Renege data on an association. */
95 SCTP_CMD_SETUP_T4, /* ADDIP, setup T4 RTO timer parms. */
96 SCTP_CMD_PROCESS_OPERR, /* Process an ERROR chunk. */
97 SCTP_CMD_REPORT_FWDTSN, /* Report new cumulative TSN Ack. */
98 SCTP_CMD_PROCESS_FWDTSN, /* Skips were reported, so process further. */
99 SCTP_CMD_CLEAR_INIT_TAG, /* Clears association peer's inittag. */
100 SCTP_CMD_DEL_NON_PRIMARY, /* Removes non-primary peer transports. */
101 SCTP_CMD_T3_RTX_TIMERS_STOP, /* Stops T3-rtx pending timers */
102 SCTP_CMD_FORCE_PRIM_RETRAN, /* Forces retrans. over primary path. */
103 SCTP_CMD_SET_SK_ERR, /* Set sk_err */
104 SCTP_CMD_ASSOC_CHANGE, /* generate and send assoc_change event */
105 SCTP_CMD_ADAPTATION_IND, /* generate and send adaptation event */
106 SCTP_CMD_ASSOC_SHKEY, /* generate the association shared keys */
107 SCTP_CMD_T1_RETRAN, /* Mark for retransmission after T1 timeout */
108 SCTP_CMD_UPDATE_INITTAG, /* Update peer inittag */
109 SCTP_CMD_SEND_MSG, /* Send the whole use message */
110 SCTP_CMD_SEND_NEXT_ASCONF, /* Send the next ASCONF after ACK */
111 SCTP_CMD_PURGE_ASCONF_QUEUE, /* Purge all asconf queues.*/
112 SCTP_CMD_SET_ASOC, /* Restore association context */
113 SCTP_CMD_LAST
114} sctp_verb_t;
115
116/* How many commands can you put in an sctp_cmd_seq_t?
117 * This is a rather arbitrary number, ideally derived from a careful
118 * analysis of the state functions, but in reality just taken from
119 * thin air in the hopes othat we don't trigger a kernel panic.
120 */
121#define SCTP_MAX_NUM_COMMANDS 14
122
123typedef union {
124 __s32 i32;
125 __u32 u32;
126 __be32 be32;
127 __u16 u16;
128 __u8 u8;
129 int error;
130 __be16 err;
131 sctp_state_t state;
132 sctp_event_timeout_t to;
133 unsigned long zero;
134 void *ptr;
135 struct sctp_chunk *chunk;
136 struct sctp_association *asoc;
137 struct sctp_transport *transport;
138 struct sctp_bind_addr *bp;
139 sctp_init_chunk_t *init;
140 struct sctp_ulpevent *ulpevent;
141 struct sctp_packet *packet;
142 sctp_sackhdr_t *sackh;
143 struct sctp_datamsg *msg;
144} sctp_arg_t;
145
146/* We are simulating ML type constructors here.
147 *
148 * SCTP_ARG_CONSTRUCTOR(NAME, TYPE, ELT) builds a function called
149 * SCTP_NAME() which takes an argument of type TYPE and returns an
150 * sctp_arg_t. It does this by inserting the sole argument into the
151 * ELT union element of a local sctp_arg_t.
152 *
153 * E.g., SCTP_ARG_CONSTRUCTOR(I32, __s32, i32) builds SCTP_I32(arg),
154 * which takes an __s32 and returns a sctp_arg_t containing the
155 * __s32. So, after foo = SCTP_I32(arg), foo.i32 == arg.
156 */
157static inline sctp_arg_t SCTP_NULL(void)
158{
159 sctp_arg_t retval; retval.ptr = NULL; return retval;
160}
161static inline sctp_arg_t SCTP_NOFORCE(void)
162{
163 sctp_arg_t retval = {.zero = 0UL}; retval.i32 = 0; return retval;
164}
165static inline sctp_arg_t SCTP_FORCE(void)
166{
167 sctp_arg_t retval = {.zero = 0UL}; retval.i32 = 1; return retval;
168}
169
170#define SCTP_ARG_CONSTRUCTOR(name, type, elt) \
171static inline sctp_arg_t \
172SCTP_## name (type arg) \
173{ sctp_arg_t retval = {.zero = 0UL}; retval.elt = arg; return retval; }
174
175SCTP_ARG_CONSTRUCTOR(I32, __s32, i32)
176SCTP_ARG_CONSTRUCTOR(U32, __u32, u32)
177SCTP_ARG_CONSTRUCTOR(BE32, __be32, be32)
178SCTP_ARG_CONSTRUCTOR(U16, __u16, u16)
179SCTP_ARG_CONSTRUCTOR(U8, __u8, u8)
180SCTP_ARG_CONSTRUCTOR(ERROR, int, error)
181SCTP_ARG_CONSTRUCTOR(PERR, __be16, err) /* protocol error */
182SCTP_ARG_CONSTRUCTOR(STATE, sctp_state_t, state)
183SCTP_ARG_CONSTRUCTOR(TO, sctp_event_timeout_t, to)
184SCTP_ARG_CONSTRUCTOR(PTR, void *, ptr)
185SCTP_ARG_CONSTRUCTOR(CHUNK, struct sctp_chunk *, chunk)
186SCTP_ARG_CONSTRUCTOR(ASOC, struct sctp_association *, asoc)
187SCTP_ARG_CONSTRUCTOR(TRANSPORT, struct sctp_transport *, transport)
188SCTP_ARG_CONSTRUCTOR(BA, struct sctp_bind_addr *, bp)
189SCTP_ARG_CONSTRUCTOR(PEER_INIT, sctp_init_chunk_t *, init)
190SCTP_ARG_CONSTRUCTOR(ULPEVENT, struct sctp_ulpevent *, ulpevent)
191SCTP_ARG_CONSTRUCTOR(PACKET, struct sctp_packet *, packet)
192SCTP_ARG_CONSTRUCTOR(SACKH, sctp_sackhdr_t *, sackh)
193SCTP_ARG_CONSTRUCTOR(DATAMSG, struct sctp_datamsg *, msg)
194
195typedef struct {
196 sctp_arg_t obj;
197 sctp_verb_t verb;
198} sctp_cmd_t;
199
200typedef struct {
201 sctp_cmd_t cmds[SCTP_MAX_NUM_COMMANDS];
202 __u8 next_free_slot;
203 __u8 next_cmd;
204} sctp_cmd_seq_t;
205
206
207/* Initialize a block of memory as a command sequence.
208 * Return 0 if the initialization fails.
209 */
210int sctp_init_cmd_seq(sctp_cmd_seq_t *seq);
211
212/* Add a command to an sctp_cmd_seq_t.
213 *
214 * Use the SCTP_* constructors defined by SCTP_ARG_CONSTRUCTOR() above
215 * to wrap data which goes in the obj argument.
216 */
217void sctp_add_cmd_sf(sctp_cmd_seq_t *seq, sctp_verb_t verb, sctp_arg_t obj);
218
219/* Return the next command structure in an sctp_cmd_seq.
220 * Return NULL at the end of the sequence.
221 */
222sctp_cmd_t *sctp_next_cmd(sctp_cmd_seq_t *seq);
223
224#endif /* __net_sctp_command_h__ */
225
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/* SCTP kernel Implementation
3 * (C) Copyright IBM Corp. 2001, 2004
4 * Copyright (C) 1999-2001 Cisco, Motorola
5 *
6 * This file is part of the SCTP kernel implementation
7 *
8 * These are the definitions needed for the command object.
9 *
10 * Please send any bug reports or fixes you make to the
11 * email address(es):
12 * lksctp developers <linux-sctp@vger.kernel.org>
13 *
14 * Written or modified by:
15 * La Monte H.P. Yarroll <piggy@acm.org>
16 * Karl Knutson <karl@athena.chicago.il.us>
17 * Ardelle Fan <ardelle.fan@intel.com>
18 * Sridhar Samudrala <sri@us.ibm.com>
19 */
20
21#ifndef __net_sctp_command_h__
22#define __net_sctp_command_h__
23
24#include <net/sctp/constants.h>
25#include <net/sctp/structs.h>
26
27
28enum sctp_verb {
29 SCTP_CMD_NOP = 0, /* Do nothing. */
30 SCTP_CMD_NEW_ASOC, /* Register a new association. */
31 SCTP_CMD_DELETE_TCB, /* Delete the current association. */
32 SCTP_CMD_NEW_STATE, /* Enter a new state. */
33 SCTP_CMD_REPORT_TSN, /* Record the arrival of a TSN. */
34 SCTP_CMD_GEN_SACK, /* Send a Selective ACK (maybe). */
35 SCTP_CMD_PROCESS_SACK, /* Process an inbound SACK. */
36 SCTP_CMD_GEN_INIT_ACK, /* Generate an INIT ACK chunk. */
37 SCTP_CMD_PEER_INIT, /* Process a INIT from the peer. */
38 SCTP_CMD_GEN_COOKIE_ECHO, /* Generate a COOKIE ECHO chunk. */
39 SCTP_CMD_CHUNK_ULP, /* Send a chunk to the sockets layer. */
40 SCTP_CMD_EVENT_ULP, /* Send a notification to the sockets layer. */
41 SCTP_CMD_REPLY, /* Send a chunk to our peer. */
42 SCTP_CMD_SEND_PKT, /* Send a full packet to our peer. */
43 SCTP_CMD_RETRAN, /* Mark a transport for retransmission. */
44 SCTP_CMD_ECN_CE, /* Do delayed CE processing. */
45 SCTP_CMD_ECN_ECNE, /* Do delayed ECNE processing. */
46 SCTP_CMD_ECN_CWR, /* Do delayed CWR processing. */
47 SCTP_CMD_TIMER_START, /* Start a timer. */
48 SCTP_CMD_TIMER_START_ONCE, /* Start a timer once */
49 SCTP_CMD_TIMER_RESTART, /* Restart a timer. */
50 SCTP_CMD_TIMER_STOP, /* Stop a timer. */
51 SCTP_CMD_INIT_CHOOSE_TRANSPORT, /* Choose transport for an INIT. */
52 SCTP_CMD_INIT_COUNTER_RESET, /* Reset init counter. */
53 SCTP_CMD_INIT_COUNTER_INC, /* Increment init counter. */
54 SCTP_CMD_INIT_RESTART, /* High level, do init timer work. */
55 SCTP_CMD_COOKIEECHO_RESTART, /* High level, do cookie-echo timer work. */
56 SCTP_CMD_INIT_FAILED, /* High level, do init failure work. */
57 SCTP_CMD_REPORT_DUP, /* Report a duplicate TSN. */
58 SCTP_CMD_STRIKE, /* Mark a strike against a transport. */
59 SCTP_CMD_HB_TIMERS_START, /* Start the heartbeat timers. */
60 SCTP_CMD_HB_TIMER_UPDATE, /* Update a heartbeat timers. */
61 SCTP_CMD_HB_TIMERS_STOP, /* Stop the heartbeat timers. */
62 SCTP_CMD_PROBE_TIMER_UPDATE, /* Update a probe timer. */
63 SCTP_CMD_TRANSPORT_HB_SENT, /* Reset the status of a transport. */
64 SCTP_CMD_TRANSPORT_IDLE, /* Do manipulations on idle transport */
65 SCTP_CMD_TRANSPORT_ON, /* Mark the transport as active. */
66 SCTP_CMD_REPORT_ERROR, /* Pass this error back out of the sm. */
67 SCTP_CMD_REPORT_BAD_TAG, /* Verification tags didn't match. */
68 SCTP_CMD_PROCESS_CTSN, /* Sideeffect from shutdown. */
69 SCTP_CMD_ASSOC_FAILED, /* Handle association failure. */
70 SCTP_CMD_DISCARD_PACKET, /* Discard the whole packet. */
71 SCTP_CMD_GEN_SHUTDOWN, /* Generate a SHUTDOWN chunk. */
72 SCTP_CMD_PURGE_OUTQUEUE, /* Purge all data waiting to be sent. */
73 SCTP_CMD_SETUP_T2, /* Hi-level, setup T2-shutdown parms. */
74 SCTP_CMD_RTO_PENDING, /* Set transport's rto_pending. */
75 SCTP_CMD_PART_DELIVER, /* Partial data delivery considerations. */
76 SCTP_CMD_RENEGE, /* Renege data on an association. */
77 SCTP_CMD_SETUP_T4, /* ADDIP, setup T4 RTO timer parms. */
78 SCTP_CMD_PROCESS_OPERR, /* Process an ERROR chunk. */
79 SCTP_CMD_REPORT_FWDTSN, /* Report new cumulative TSN Ack. */
80 SCTP_CMD_PROCESS_FWDTSN, /* Skips were reported, so process further. */
81 SCTP_CMD_CLEAR_INIT_TAG, /* Clears association peer's inittag. */
82 SCTP_CMD_DEL_NON_PRIMARY, /* Removes non-primary peer transports. */
83 SCTP_CMD_T3_RTX_TIMERS_STOP, /* Stops T3-rtx pending timers */
84 SCTP_CMD_FORCE_PRIM_RETRAN, /* Forces retrans. over primary path. */
85 SCTP_CMD_SET_SK_ERR, /* Set sk_err */
86 SCTP_CMD_ASSOC_CHANGE, /* generate and send assoc_change event */
87 SCTP_CMD_ADAPTATION_IND, /* generate and send adaptation event */
88 SCTP_CMD_PEER_NO_AUTH, /* generate and send authentication event */
89 SCTP_CMD_ASSOC_SHKEY, /* generate the association shared keys */
90 SCTP_CMD_T1_RETRAN, /* Mark for retransmission after T1 timeout */
91 SCTP_CMD_UPDATE_INITTAG, /* Update peer inittag */
92 SCTP_CMD_SEND_MSG, /* Send the whole use message */
93 SCTP_CMD_PURGE_ASCONF_QUEUE, /* Purge all asconf queues.*/
94 SCTP_CMD_SET_ASOC, /* Restore association context */
95 SCTP_CMD_LAST
96};
97
98/* How many commands can you put in an struct sctp_cmd_seq?
99 * This is a rather arbitrary number, ideally derived from a careful
100 * analysis of the state functions, but in reality just taken from
101 * thin air in the hopes othat we don't trigger a kernel panic.
102 */
103#define SCTP_MAX_NUM_COMMANDS 20
104
105union sctp_arg {
106 void *zero_all; /* Set to NULL to clear the entire union */
107 __s32 i32;
108 __u32 u32;
109 __be32 be32;
110 __u16 u16;
111 __u8 u8;
112 int error;
113 __be16 err;
114 enum sctp_state state;
115 enum sctp_event_timeout to;
116 struct sctp_chunk *chunk;
117 struct sctp_association *asoc;
118 struct sctp_transport *transport;
119 struct sctp_bind_addr *bp;
120 struct sctp_init_chunk *init;
121 struct sctp_ulpevent *ulpevent;
122 struct sctp_packet *packet;
123 struct sctp_sackhdr *sackh;
124 struct sctp_datamsg *msg;
125};
126
127/* We are simulating ML type constructors here.
128 *
129 * SCTP_ARG_CONSTRUCTOR(NAME, TYPE, ELT) builds a function called
130 * SCTP_NAME() which takes an argument of type TYPE and returns an
131 * union sctp_arg. It does this by inserting the sole argument into
132 * the ELT union element of a local union sctp_arg.
133 *
134 * E.g., SCTP_ARG_CONSTRUCTOR(I32, __s32, i32) builds SCTP_I32(arg),
135 * which takes an __s32 and returns a union sctp_arg containing the
136 * __s32. So, after foo = SCTP_I32(arg), foo.i32 == arg.
137 */
138
139#define SCTP_ARG_CONSTRUCTOR(name, type, elt) \
140static inline union sctp_arg \
141SCTP_## name (type arg) \
142{ union sctp_arg retval;\
143 retval.zero_all = NULL;\
144 retval.elt = arg;\
145 return retval;\
146}
147
148SCTP_ARG_CONSTRUCTOR(I32, __s32, i32)
149SCTP_ARG_CONSTRUCTOR(U32, __u32, u32)
150SCTP_ARG_CONSTRUCTOR(BE32, __be32, be32)
151SCTP_ARG_CONSTRUCTOR(U16, __u16, u16)
152SCTP_ARG_CONSTRUCTOR(U8, __u8, u8)
153SCTP_ARG_CONSTRUCTOR(ERROR, int, error)
154SCTP_ARG_CONSTRUCTOR(PERR, __be16, err) /* protocol error */
155SCTP_ARG_CONSTRUCTOR(STATE, enum sctp_state, state)
156SCTP_ARG_CONSTRUCTOR(TO, enum sctp_event_timeout, to)
157SCTP_ARG_CONSTRUCTOR(CHUNK, struct sctp_chunk *, chunk)
158SCTP_ARG_CONSTRUCTOR(ASOC, struct sctp_association *, asoc)
159SCTP_ARG_CONSTRUCTOR(TRANSPORT, struct sctp_transport *, transport)
160SCTP_ARG_CONSTRUCTOR(BA, struct sctp_bind_addr *, bp)
161SCTP_ARG_CONSTRUCTOR(PEER_INIT, struct sctp_init_chunk *, init)
162SCTP_ARG_CONSTRUCTOR(ULPEVENT, struct sctp_ulpevent *, ulpevent)
163SCTP_ARG_CONSTRUCTOR(PACKET, struct sctp_packet *, packet)
164SCTP_ARG_CONSTRUCTOR(SACKH, struct sctp_sackhdr *, sackh)
165SCTP_ARG_CONSTRUCTOR(DATAMSG, struct sctp_datamsg *, msg)
166
167static inline union sctp_arg SCTP_FORCE(void)
168{
169 return SCTP_I32(1);
170}
171
172static inline union sctp_arg SCTP_NOFORCE(void)
173{
174 return SCTP_I32(0);
175}
176
177static inline union sctp_arg SCTP_NULL(void)
178{
179 union sctp_arg retval;
180 retval.zero_all = NULL;
181 return retval;
182}
183
184struct sctp_cmd {
185 union sctp_arg obj;
186 enum sctp_verb verb;
187};
188
189struct sctp_cmd_seq {
190 struct sctp_cmd cmds[SCTP_MAX_NUM_COMMANDS];
191 struct sctp_cmd *last_used_slot;
192 struct sctp_cmd *next_cmd;
193};
194
195
196/* Initialize a block of memory as a command sequence.
197 * Return 0 if the initialization fails.
198 */
199static inline int sctp_init_cmd_seq(struct sctp_cmd_seq *seq)
200{
201 /* cmds[] is filled backwards to simplify the overflow BUG() check */
202 seq->last_used_slot = seq->cmds + SCTP_MAX_NUM_COMMANDS;
203 seq->next_cmd = seq->last_used_slot;
204 return 1; /* We always succeed. */
205}
206
207
208/* Add a command to an struct sctp_cmd_seq.
209 *
210 * Use the SCTP_* constructors defined by SCTP_ARG_CONSTRUCTOR() above
211 * to wrap data which goes in the obj argument.
212 */
213static inline void sctp_add_cmd_sf(struct sctp_cmd_seq *seq,
214 enum sctp_verb verb, union sctp_arg obj)
215{
216 struct sctp_cmd *cmd = seq->last_used_slot - 1;
217
218 BUG_ON(cmd < seq->cmds);
219
220 cmd->verb = verb;
221 cmd->obj = obj;
222 seq->last_used_slot = cmd;
223}
224
225/* Return the next command structure in an sctp_cmd_seq.
226 * Return NULL at the end of the sequence.
227 */
228static inline struct sctp_cmd *sctp_next_cmd(struct sctp_cmd_seq *seq)
229{
230 if (seq->next_cmd <= seq->last_used_slot)
231 return NULL;
232
233 return --seq->next_cmd;
234}
235
236#endif /* __net_sctp_command_h__ */