xref: /freebsd/sys/netinet/sctp_os_bsd.h (revision 5dd76dd0cc19450133aa379ce0ce4a68ae07fb39)
1 /*-
2  * Copyright (c) 2006-2007, by Cisco Systems, Inc. All rights reserved.
3  * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
4  * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions are met:
8  *
9  * a) Redistributions of source code must retain the above copyright notice,
10  *   this list of conditions and the following disclaimer.
11  *
12  * b) Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in
14  *   the documentation and/or other materials provided with the distribution.
15  *
16  * c) Neither the name of Cisco Systems, Inc. nor the names of its
17  *    contributors may be used to endorse or promote products derived
18  *    from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
22  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
24  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
30  * THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #ifndef _NETINET_SCTP_OS_BSD_H_
37 #define _NETINET_SCTP_OS_BSD_H_
38 /*
39  * includes
40  */
41 #include "opt_ipsec.h"
42 #include "opt_compat.h"
43 #include "opt_inet6.h"
44 #include "opt_inet.h"
45 #include "opt_sctp.h"
46 
47 #include <sys/param.h>
48 #include <sys/ktr.h>
49 #include <sys/systm.h>
50 #include <sys/malloc.h>
51 #include <sys/kernel.h>
52 #include <sys/sysctl.h>
53 #include <sys/mbuf.h>
54 #include <sys/protosw.h>
55 #include <sys/socket.h>
56 #include <sys/socketvar.h>
57 #include <sys/jail.h>
58 #include <sys/sysctl.h>
59 #include <sys/resourcevar.h>
60 #include <sys/uio.h>
61 #include <sys/lock.h>
62 #include <sys/rwlock.h>
63 #include <sys/kthread.h>
64 #include <sys/priv.h>
65 #include <sys/random.h>
66 #include <sys/limits.h>
67 #include <sys/queue.h>
68 #include <machine/cpu.h>
69 
70 #include <net/if.h>
71 #include <net/if_types.h>
72 #include <net/if_var.h>
73 #include <net/route.h>
74 #include <net/vnet.h>
75 
76 #include <netinet/in.h>
77 #include <netinet/in_systm.h>
78 #include <netinet/ip.h>
79 #include <netinet/in_pcb.h>
80 #include <netinet/in_var.h>
81 #include <netinet/ip_var.h>
82 #include <netinet/ip_icmp.h>
83 #include <netinet/icmp_var.h>
84 
85 #ifdef IPSEC
86 #include <netipsec/ipsec.h>
87 #include <netipsec/key.h>
88 #endif				/* IPSEC */
89 
90 #ifdef INET6
91 #include <sys/domain.h>
92 #ifdef IPSEC
93 #include <netipsec/ipsec6.h>
94 #endif
95 #include <netinet/ip6.h>
96 #include <netinet6/ip6_var.h>
97 #include <netinet6/in6_pcb.h>
98 #include <netinet/icmp6.h>
99 #include <netinet6/ip6protosw.h>
100 #include <netinet6/nd6.h>
101 #include <netinet6/scope6_var.h>
102 #endif				/* INET6 */
103 
104 
105 #include <netinet/ip_options.h>
106 
107 #include <crypto/sha1.h>
108 #include <crypto/sha2/sha2.h>
109 
110 #ifndef in6pcb
111 #define in6pcb		inpcb
112 #endif
113 /* Declare all the malloc names for all the various mallocs */
114 MALLOC_DECLARE(SCTP_M_MAP);
115 MALLOC_DECLARE(SCTP_M_STRMI);
116 MALLOC_DECLARE(SCTP_M_STRMO);
117 MALLOC_DECLARE(SCTP_M_ASC_ADDR);
118 MALLOC_DECLARE(SCTP_M_ASC_IT);
119 MALLOC_DECLARE(SCTP_M_AUTH_CL);
120 MALLOC_DECLARE(SCTP_M_AUTH_KY);
121 MALLOC_DECLARE(SCTP_M_AUTH_HL);
122 MALLOC_DECLARE(SCTP_M_AUTH_IF);
123 MALLOC_DECLARE(SCTP_M_STRESET);
124 MALLOC_DECLARE(SCTP_M_CMSG);
125 MALLOC_DECLARE(SCTP_M_COPYAL);
126 MALLOC_DECLARE(SCTP_M_VRF);
127 MALLOC_DECLARE(SCTP_M_IFA);
128 MALLOC_DECLARE(SCTP_M_IFN);
129 MALLOC_DECLARE(SCTP_M_TIMW);
130 MALLOC_DECLARE(SCTP_M_MVRF);
131 MALLOC_DECLARE(SCTP_M_ITER);
132 MALLOC_DECLARE(SCTP_M_SOCKOPT);
133 MALLOC_DECLARE(SCTP_M_MCORE);
134 
135 #if defined(SCTP_LOCAL_TRACE_BUF)
136 
137 #define SCTP_GET_CYCLECOUNT get_cyclecount()
138 #define SCTP_CTR6 sctp_log_trace
139 
140 #else
141 #define SCTP_CTR6 CTR6
142 #endif
143 
144 /*
145  * Macros to expand out globals defined by various modules
146  * to either a real global or a virtualized instance of one,
147  * depending on whether VIMAGE is defined.
148  */
149 /* then define the macro(s) that hook into the vimage macros */
150 #define MODULE_GLOBAL(__SYMBOL) V_##__SYMBOL
151 
152 #define V_system_base_info VNET(system_base_info)
153 #define SCTP_BASE_INFO(__m) V_system_base_info.sctppcbinfo.__m
154 #define SCTP_BASE_STATS V_system_base_info.sctpstat
155 #define SCTP_BASE_STATS_SYSCTL VNET_NAME(system_base_info.sctpstat)
156 #define SCTP_BASE_STAT(__m)     V_system_base_info.sctpstat.__m
157 #define SCTP_BASE_SYSCTL(__m) VNET_NAME(system_base_info.sctpsysctl.__m)
158 #define SCTP_BASE_VAR(__m) V_system_base_info.__m
159 
160 /*
161  *
162  */
163 #define USER_ADDR_NULL	(NULL)	/* FIX ME: temp */
164 
165 #define SCTP_PRINTF(params...)	printf(params)
166 #if defined(SCTP_DEBUG)
167 #define SCTPDBG(level, params...)					\
168 {									\
169     do {								\
170 	if (SCTP_BASE_SYSCTL(sctp_debug_on) & level ) {			\
171 	    SCTP_PRINTF(params);						\
172 	}								\
173     } while (0);							\
174 }
175 #define SCTPDBG_ADDR(level, addr)					\
176 {									\
177     do {								\
178 	if (SCTP_BASE_SYSCTL(sctp_debug_on) & level ) {			\
179 	    sctp_print_address(addr);					\
180 	}								\
181     } while (0);							\
182 }
183 #else
184 #define SCTPDBG(level, params...)
185 #define SCTPDBG_ADDR(level, addr)
186 #endif
187 
188 #ifdef SCTP_LTRACE_CHUNKS
189 #define SCTP_LTRACE_CHK(a, b, c, d) if(SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_LTRACE_CHUNK_ENABLE) SCTP_CTR6(KTR_SUBSYS, "SCTP:%d[%d]:%x-%x-%x-%x", SCTP_LOG_CHUNK_PROC, 0, a, b, c, d)
190 #else
191 #define SCTP_LTRACE_CHK(a, b, c, d)
192 #endif
193 
194 #ifdef SCTP_LTRACE_ERRORS
195 #define SCTP_LTRACE_ERR_RET_PKT(m, inp, stcb, net, file, err) \
196 	if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_LTRACE_ERROR_ENABLE) \
197         	SCTP_PRINTF("mbuf:%p inp:%p stcb:%p net:%p file:%x line:%d error:%d\n", \
198 		            m, inp, stcb, net, file, __LINE__, err);
199 #define SCTP_LTRACE_ERR_RET(inp, stcb, net, file, err) \
200 	if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_LTRACE_ERROR_ENABLE) \
201         	SCTP_PRINTF("inp:%p stcb:%p net:%p file:%x line:%d error:%d\n", \
202 		            inp, stcb, net, file, __LINE__, err);
203 #else
204 #define SCTP_LTRACE_ERR_RET_PKT(m, inp, stcb, net, file, err)
205 #define SCTP_LTRACE_ERR_RET(inp, stcb, net, file, err)
206 #endif
207 
208 
209 /*
210  * Local address and interface list handling
211  */
212 #define SCTP_MAX_VRF_ID		0
213 #define SCTP_SIZE_OF_VRF_HASH	3
214 #define SCTP_IFNAMSIZ		IFNAMSIZ
215 #define SCTP_DEFAULT_VRFID	0
216 #define SCTP_VRF_ADDR_HASH_SIZE	16
217 #define SCTP_VRF_IFN_HASH_SIZE	3
218 #define	SCTP_INIT_VRF_TABLEID(vrf)
219 
220 #define SCTP_IFN_IS_IFT_LOOP(ifn) ((ifn)->ifn_type == IFT_LOOP)
221 #define SCTP_ROUTE_IS_REAL_LOOP(ro) ((ro)->ro_rt && (ro)->ro_rt->rt_ifa && (ro)->ro_rt->rt_ifa->ifa_ifp && (ro)->ro_rt->rt_ifa->ifa_ifp->if_type == IFT_LOOP)
222 
223 /*
224  * Access to IFN's to help with src-addr-selection
225  */
226 /* This could return VOID if the index works but for BSD we provide both. */
227 #define SCTP_GET_IFN_VOID_FROM_ROUTE(ro) (void *)ro->ro_rt->rt_ifp
228 #define SCTP_GET_IF_INDEX_FROM_ROUTE(ro) (ro)->ro_rt->rt_ifp->if_index
229 #define SCTP_ROUTE_HAS_VALID_IFN(ro) ((ro)->ro_rt && (ro)->ro_rt->rt_ifp)
230 
231 /*
232  * general memory allocation
233  */
234 #define SCTP_MALLOC(var, type, size, name) \
235     do { \
236 	var = (type)malloc(size, name, M_NOWAIT); \
237     } while (0)
238 
239 #define SCTP_FREE(var, type)	free(var, type)
240 
241 #define SCTP_MALLOC_SONAME(var, type, size) \
242     do { \
243 	var = (type)malloc(size, M_SONAME, M_WAITOK | M_ZERO); \
244     } while (0)
245 
246 #define SCTP_FREE_SONAME(var)	free(var, M_SONAME)
247 
248 #define SCTP_PROCESS_STRUCT struct proc *
249 
250 /*
251  * zone allocation functions
252  */
253 #include <vm/uma.h>
254 
255 /* SCTP_ZONE_INIT: initialize the zone */
256 typedef struct uma_zone *sctp_zone_t;
257 
258 #define SCTP_ZONE_INIT(zone, name, size, number) { \
259 	zone = uma_zcreate(name, size, NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,\
260 		0); \
261 	uma_zone_set_max(zone, number); \
262 }
263 
264 #define SCTP_ZONE_DESTROY(zone) uma_zdestroy(zone)
265 
266 /* SCTP_ZONE_GET: allocate element from the zone */
267 #define SCTP_ZONE_GET(zone, type) \
268 	(type *)uma_zalloc(zone, M_NOWAIT);
269 
270 /* SCTP_ZONE_FREE: free element from the zone */
271 #define SCTP_ZONE_FREE(zone, element) \
272 	uma_zfree(zone, element);
273 
274 #define SCTP_HASH_INIT(size, hashmark) hashinit_flags(size, M_PCB, hashmark, HASH_NOWAIT)
275 #define SCTP_HASH_FREE(table, hashmark) hashdestroy(table, M_PCB, hashmark)
276 
277 #define SCTP_M_COPYM	m_copym
278 
279 /*
280  * timers
281  */
282 #include <sys/callout.h>
283 typedef struct callout sctp_os_timer_t;
284 
285 
286 #define SCTP_OS_TIMER_INIT(tmr)	callout_init(tmr, 1)
287 #define SCTP_OS_TIMER_START	callout_reset
288 #define SCTP_OS_TIMER_STOP	callout_stop
289 #define SCTP_OS_TIMER_STOP_DRAIN callout_drain
290 #define SCTP_OS_TIMER_PENDING	callout_pending
291 #define SCTP_OS_TIMER_ACTIVE	callout_active
292 #define SCTP_OS_TIMER_DEACTIVATE callout_deactivate
293 
294 #define sctp_get_tick_count() (ticks)
295 
296 #define SCTP_UNUSED __attribute__((unused))
297 
298 /*
299  * Functions
300  */
301 /* Mbuf manipulation and access macros  */
302 #define SCTP_BUF_LEN(m) (m->m_len)
303 #define SCTP_BUF_NEXT(m) (m->m_next)
304 #define SCTP_BUF_NEXT_PKT(m) (m->m_nextpkt)
305 #define SCTP_BUF_RESV_UF(m, size) m->m_data += size
306 #define SCTP_BUF_AT(m, size) m->m_data + size
307 #define SCTP_BUF_IS_EXTENDED(m) (m->m_flags & M_EXT)
308 #define SCTP_BUF_EXTEND_SIZE(m) (m->m_ext.ext_size)
309 #define SCTP_BUF_TYPE(m) (m->m_type)
310 #define SCTP_BUF_RECVIF(m) (m->m_pkthdr.rcvif)
311 #define SCTP_BUF_PREPEND	M_PREPEND
312 
313 #define SCTP_ALIGN_TO_END(m, len) if(m->m_flags & M_PKTHDR) { \
314                                      MH_ALIGN(m, len); \
315                                   } else if ((m->m_flags & M_EXT) == 0) { \
316                                      M_ALIGN(m, len); \
317                                   }
318 
319 /* We make it so if you have up to 4 threads
320  * writing based on the default size of
321  * the packet log 65 k, that would be
322  * 4 16k packets before we would hit
323  * a problem.
324  */
325 #define SCTP_PKTLOG_WRITERS_NEED_LOCK 3
326 
327 /*************************/
328 /*      MTU              */
329 /*************************/
330 #define SCTP_GATHER_MTU_FROM_IFN_INFO(ifn, ifn_index, af) ((struct ifnet *)ifn)->if_mtu
331 #define SCTP_GATHER_MTU_FROM_ROUTE(sctp_ifa, sa, rt) ((rt != NULL) ? rt->rt_rmx.rmx_mtu : 0)
332 #define SCTP_GATHER_MTU_FROM_INTFC(sctp_ifn) ((sctp_ifn->ifn_p != NULL) ? ((struct ifnet *)(sctp_ifn->ifn_p))->if_mtu : 0)
333 #define SCTP_SET_MTU_OF_ROUTE(sa, rt, mtu) do { \
334                                               if (rt != NULL) \
335                                                  rt->rt_rmx.rmx_mtu = mtu; \
336                                            } while(0)
337 
338 /* (de-)register interface event notifications */
339 #define SCTP_REGISTER_INTERFACE(ifhandle, af)
340 #define SCTP_DEREGISTER_INTERFACE(ifhandle, af)
341 
342 
343 /*************************/
344 /* These are for logging */
345 /*************************/
346 /* return the base ext data pointer */
347 #define SCTP_BUF_EXTEND_BASE(m) (m->m_ext.ext_buf)
348  /* return the refcnt of the data pointer */
349 #define SCTP_BUF_EXTEND_REFCNT(m) (*m->m_ext.ref_cnt)
350 /* return any buffer related flags, this is
351  * used beyond logging for apple only.
352  */
353 #define SCTP_BUF_GET_FLAGS(m) (m->m_flags)
354 
355 /* For BSD this just accesses the M_PKTHDR length
356  * so it operates on an mbuf with hdr flag. Other
357  * O/S's may have separate packet header and mbuf
358  * chain pointers.. thus the macro.
359  */
360 #define SCTP_HEADER_TO_CHAIN(m) (m)
361 #define SCTP_DETACH_HEADER_FROM_CHAIN(m)
362 #define SCTP_HEADER_LEN(m) ((m)->m_pkthdr.len)
363 #define SCTP_GET_HEADER_FOR_OUTPUT(o_pak) 0
364 #define SCTP_RELEASE_HEADER(m)
365 #define SCTP_RELEASE_PKT(m)	sctp_m_freem(m)
366 #define SCTP_ENABLE_UDP_CSUM(m) do { \
367 					m->m_pkthdr.csum_flags = CSUM_UDP; \
368 					m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum); \
369 				} while (0)
370 
371 #define SCTP_GET_PKT_VRFID(m, vrf_id)  ((vrf_id = SCTP_DEFAULT_VRFID) != SCTP_DEFAULT_VRFID)
372 
373 
374 
375 /* Attach the chain of data into the sendable packet. */
376 #define SCTP_ATTACH_CHAIN(pak, m, packet_length) do { \
377                                                  pak = m; \
378                                                  pak->m_pkthdr.len = packet_length; \
379                          } while(0)
380 
381 /* Other m_pkthdr type things */
382 #define SCTP_IS_IT_BROADCAST(dst, m) ((m->m_flags & M_PKTHDR) ? in_broadcast(dst, m->m_pkthdr.rcvif) : 0)
383 #define SCTP_IS_IT_LOOPBACK(m) ((m->m_flags & M_PKTHDR) && ((m->m_pkthdr.rcvif == NULL) || (m->m_pkthdr.rcvif->if_type == IFT_LOOP)))
384 
385 
386 /* This converts any input packet header
387  * into the chain of data holders, for BSD
388  * its a NOP.
389  */
390 
391 /* get the v6 hop limit */
392 #define SCTP_GET_HLIM(inp, ro)	in6_selecthlim((struct in6pcb *)&inp->ip_inp.inp, (ro ? (ro->ro_rt ? (ro->ro_rt->rt_ifp) : (NULL)) : (NULL)));
393 
394 /* is the endpoint v6only? */
395 #define SCTP_IPV6_V6ONLY(inp)	(((struct inpcb *)inp)->inp_flags & IN6P_IPV6_V6ONLY)
396 /* is the socket non-blocking? */
397 #define SCTP_SO_IS_NBIO(so)	((so)->so_state & SS_NBIO)
398 #define SCTP_SET_SO_NBIO(so)	((so)->so_state |= SS_NBIO)
399 #define SCTP_CLEAR_SO_NBIO(so)	((so)->so_state &= ~SS_NBIO)
400 /* get the socket type */
401 #define SCTP_SO_TYPE(so)	((so)->so_type)
402 /* reserve sb space for a socket */
403 #define SCTP_SORESERVE(so, send, recv)	soreserve(so, send, recv)
404 /* wakeup a socket */
405 #define SCTP_SOWAKEUP(so)	wakeup(&(so)->so_timeo)
406 /* clear the socket buffer state */
407 #define SCTP_SB_CLEAR(sb)	\
408 	(sb).sb_cc = 0;		\
409 	(sb).sb_mb = NULL;	\
410 	(sb).sb_mbcnt = 0;
411 
412 #define SCTP_SB_LIMIT_RCV(so) so->so_rcv.sb_hiwat
413 #define SCTP_SB_LIMIT_SND(so) so->so_snd.sb_hiwat
414 
415 /*
416  * routes, output, etc.
417  */
418 typedef struct route sctp_route_t;
419 typedef struct rtentry sctp_rtentry_t;
420 
421 /*
422  * XXX multi-FIB support was backed out in r179783 and it seems clear that the
423  * VRF support as currently in FreeBSD is not ready to support multi-FIB.
424  * It might be best to implement multi-FIB support for both v4 and v6 indepedent
425  * of VRFs and leave those to a real MPLS stack.
426  */
427 #define SCTP_RTALLOC(ro, vrf_id) rtalloc_ign((struct route *)ro, 0UL)
428 
429 /* Future zero copy wakeup/send  function */
430 #define SCTP_ZERO_COPY_EVENT(inp, so)
431 /* This is re-pulse ourselves for sendbuf */
432 #define SCTP_ZERO_COPY_SENDQ_EVENT(inp, so)
433 
434 /*
435  * SCTP protocol specific mbuf flags.
436  */
437 #define	M_NOTIFICATION		M_PROTO1	/* SCTP notification */
438 
439 /*
440  * IP output routines
441  */
442 #define SCTP_IP_OUTPUT(result, o_pak, ro, stcb, vrf_id) \
443 { \
444 	int o_flgs = IP_RAWOUTPUT; \
445 	struct sctp_tcb *local_stcb = stcb; \
446 	if (local_stcb && \
447 	    local_stcb->sctp_ep && \
448 	    local_stcb->sctp_ep->sctp_socket) \
449 		o_flgs |= local_stcb->sctp_ep->sctp_socket->so_options & SO_DONTROUTE; \
450 	m_clrprotoflags(o_pak); \
451 	result = ip_output(o_pak, NULL, ro, o_flgs, 0, NULL); \
452 }
453 
454 #define SCTP_IP6_OUTPUT(result, o_pak, ro, ifp, stcb, vrf_id) \
455 { \
456 	struct sctp_tcb *local_stcb = stcb; \
457 	m_clrprotoflags(o_pak); \
458 	if (local_stcb && local_stcb->sctp_ep) \
459 		result = ip6_output(o_pak, \
460 				    ((struct in6pcb *)(local_stcb->sctp_ep))->in6p_outputopts, \
461 				    (ro), 0, 0, ifp, NULL); \
462 	else \
463 		result = ip6_output(o_pak, NULL, (ro), 0, 0, ifp, NULL); \
464 }
465 
466 struct mbuf *
467 sctp_get_mbuf_for_msg(unsigned int space_needed,
468     int want_header, int how, int allonebuf, int type);
469 
470 
471 /*
472  * SCTP AUTH
473  */
474 #define SCTP_READ_RANDOM(buf, len)	read_random(buf, len)
475 
476 /* map standard crypto API names */
477 #define SCTP_SHA1_CTX		SHA1_CTX
478 #define SCTP_SHA1_INIT		SHA1Init
479 #define SCTP_SHA1_UPDATE	SHA1Update
480 #define SCTP_SHA1_FINAL(x,y)	SHA1Final((caddr_t)x, y)
481 
482 #define SCTP_SHA256_CTX		SHA256_CTX
483 #define SCTP_SHA256_INIT	SHA256_Init
484 #define SCTP_SHA256_UPDATE	SHA256_Update
485 #define SCTP_SHA256_FINAL(x,y)	SHA256_Final((caddr_t)x, y)
486 
487 #endif
488 
489 #define SCTP_DECREMENT_AND_CHECK_REFCOUNT(addr) (atomic_fetchadd_int(addr, -1) == 1)
490 #if defined(INVARIANTS)
491 #define SCTP_SAVE_ATOMIC_DECREMENT(addr, val) \
492 { \
493 	int32_t oldval; \
494 	oldval = atomic_fetchadd_int(addr, -val); \
495 	if (oldval < val) { \
496 		panic("Counter goes negative"); \
497 	} \
498 }
499 #else
500 #define SCTP_SAVE_ATOMIC_DECREMENT(addr, val) \
501 { \
502 	int32_t oldval; \
503 	oldval = atomic_fetchadd_int(addr, -val); \
504 	if (oldval < val) { \
505 		*addr = 0; \
506 	} \
507 }
508 #endif
509