sys/netinet/sctp_os_bsd.h

   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 <netinet6/ip6protosw.h>
  99 #include <netinet6/nd6.h>
 100 #include <netinet6/scope6_var.h>
 101 #endif                          /* INET6 */
 102
 103
 104 #include <netinet/ip_options.h>
 105
 106 #include <crypto/sha1.h>
 107 #include <crypto/sha2/sha256.h>
 108
 109 #ifndef in6pcb
 110 #define in6pcb          inpcb
 111 #endif
 112 /* Declare all the malloc names for all the various mallocs */
 113 MALLOC_DECLARE(SCTP_M_MAP);
 114 MALLOC_DECLARE(SCTP_M_STRMI);
 115 MALLOC_DECLARE(SCTP_M_STRMO);
 116 MALLOC_DECLARE(SCTP_M_ASC_ADDR);
 117 MALLOC_DECLARE(SCTP_M_ASC_IT);
 118 MALLOC_DECLARE(SCTP_M_AUTH_CL);
 119 MALLOC_DECLARE(SCTP_M_AUTH_KY);
 120 MALLOC_DECLARE(SCTP_M_AUTH_HL);
 121 MALLOC_DECLARE(SCTP_M_AUTH_IF);
 122 MALLOC_DECLARE(SCTP_M_STRESET);
 123 MALLOC_DECLARE(SCTP_M_CMSG);
 124 MALLOC_DECLARE(SCTP_M_COPYAL);
 125 MALLOC_DECLARE(SCTP_M_VRF);
 126 MALLOC_DECLARE(SCTP_M_IFA);
 127 MALLOC_DECLARE(SCTP_M_IFN);
 128 MALLOC_DECLARE(SCTP_M_TIMW);
 129 MALLOC_DECLARE(SCTP_M_MVRF);
 130 MALLOC_DECLARE(SCTP_M_ITER);
 131 MALLOC_DECLARE(SCTP_M_SOCKOPT);
 132 MALLOC_DECLARE(SCTP_M_MCORE);
 133
 134 #if defined(SCTP_LOCAL_TRACE_BUF)
 135
 136 #define SCTP_GET_CYCLECOUNT get_cyclecount()
 137 #define SCTP_CTR6 sctp_log_trace
 138
 139 #else
 140 #define SCTP_CTR6 CTR6
 141 #endif
 142
 143 /*
 144  * Macros to expand out globals defined by various modules
 145  * to either a real global or a virtualized instance of one,
 146  * depending on whether VIMAGE is defined.
 147  */
 148 /* then define the macro(s) that hook into the vimage macros */
 149 #define MODULE_GLOBAL(__SYMBOL) V_##__SYMBOL
 150
 151 #define V_system_base_info VNET(system_base_info)
 152 #define SCTP_BASE_INFO(__m) V_system_base_info.sctppcbinfo.__m
 153 #define SCTP_BASE_STATS V_system_base_info.sctpstat
 154 #define SCTP_BASE_STAT(__m) V_system_base_info.sctpstat.__m
 155 #define SCTP_BASE_SYSCTL(__m) V_system_base_info.sctpsysctl.__m
 156 #define SCTP_BASE_VAR(__m) V_system_base_info.__m
 157
 158 #define SCTP_PRINTF(params...)  printf(params)
 159 #if defined(SCTP_DEBUG)
 160 #define SCTPDBG(level, params...)                                       \
 161 {                                                                       \
 162         do {                                                            \
 163                 if (SCTP_BASE_SYSCTL(sctp_debug_on) & level ) {         \
 164                         SCTP_PRINTF(params);                            \
 165                 }                                                       \
 166         } while (0);                                                    \
 167 }
 168 #define SCTPDBG_ADDR(level, addr)                                       \
 169 {                                                                       \
 170         do {                                                            \
 171                 if (SCTP_BASE_SYSCTL(sctp_debug_on) & level ) {         \
 172                         sctp_print_address(addr);                       \
 173                 }                                                       \
 174         } while (0);                                                    \
 175 }
 176 #else
 177 #define SCTPDBG(level, params...)
 178 #define SCTPDBG_ADDR(level, addr)
 179 #endif
 180
 181 #ifdef SCTP_LTRACE_CHUNKS
 182 #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)
 183 #else
 184 #define SCTP_LTRACE_CHK(a, b, c, d)
 185 #endif
 186
 187 #ifdef SCTP_LTRACE_ERRORS
 188 #define SCTP_LTRACE_ERR_RET_PKT(m, inp, stcb, net, file, err) \
 189         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_LTRACE_ERROR_ENABLE) \
 190                 SCTP_PRINTF("mbuf:%p inp:%p stcb:%p net:%p file:%x line:%d error:%d\n", \
 191                             m, inp, stcb, net, file, __LINE__, err);
 192 #define SCTP_LTRACE_ERR_RET(inp, stcb, net, file, err) \
 193         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_LTRACE_ERROR_ENABLE) \
 194                 SCTP_PRINTF("inp:%p stcb:%p net:%p file:%x line:%d error:%d\n", \
 195                             inp, stcb, net, file, __LINE__, err);
 196 #else
 197 #define SCTP_LTRACE_ERR_RET_PKT(m, inp, stcb, net, file, err)
 198 #define SCTP_LTRACE_ERR_RET(inp, stcb, net, file, err)
 199 #endif
 200
 201
 202 /*
 203  * Local address and interface list handling
 204  */
 205 #define SCTP_MAX_VRF_ID         0
 206 #define SCTP_SIZE_OF_VRF_HASH   3
 207 #define SCTP_IFNAMSIZ           IFNAMSIZ
 208 #define SCTP_DEFAULT_VRFID      0
 209 #define SCTP_VRF_ADDR_HASH_SIZE 16
 210 #define SCTP_VRF_IFN_HASH_SIZE  3
 211 #define SCTP_INIT_VRF_TABLEID(vrf)
 212
 213 #define SCTP_IFN_IS_IFT_LOOP(ifn) ((ifn)->ifn_type == IFT_LOOP)
 214 #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)
 215
 216 /*
 217  * Access to IFN's to help with src-addr-selection
 218  */
 219 /* This could return VOID if the index works but for BSD we provide both. */
 220 #define SCTP_GET_IFN_VOID_FROM_ROUTE(ro) (void *)ro->ro_rt->rt_ifp
 221 #define SCTP_GET_IF_INDEX_FROM_ROUTE(ro) (ro)->ro_rt->rt_ifp->if_index
 222 #define SCTP_ROUTE_HAS_VALID_IFN(ro) ((ro)->ro_rt && (ro)->ro_rt->rt_ifp)
 223
 224 /*
 225  * general memory allocation
 226  */
 227 #define SCTP_MALLOC(var, type, size, name) \
 228         do { \
 229                 var = (type)malloc(size, name, M_NOWAIT); \
 230         } while (0)
 231
 232 #define SCTP_FREE(var, type)    free(var, type)
 233
 234 #define SCTP_MALLOC_SONAME(var, type, size) \
 235         do { \
 236                 var = (type)malloc(size, M_SONAME, M_WAITOK | M_ZERO); \
 237         } while (0)
 238
 239 #define SCTP_FREE_SONAME(var)   free(var, M_SONAME)
 240
 241 #define SCTP_PROCESS_STRUCT struct proc *
 242
 243 /*
 244  * zone allocation functions
 245  */
 246 #include <vm/uma.h>
 247
 248 /* SCTP_ZONE_INIT: initialize the zone */
 249 typedef struct uma_zone *sctp_zone_t;
 250
 251 #define SCTP_ZONE_INIT(zone, name, size, number) { \
 252         zone = uma_zcreate(name, size, NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,\
 253                 0); \
 254         uma_zone_set_max(zone, number); \
 255 }
 256
 257 #define SCTP_ZONE_DESTROY(zone) uma_zdestroy(zone)
 258
 259 /* SCTP_ZONE_GET: allocate element from the zone */
 260 #define SCTP_ZONE_GET(zone, type) \
 261         (type *)uma_zalloc(zone, M_NOWAIT);
 262
 263 /* SCTP_ZONE_FREE: free element from the zone */
 264 #define SCTP_ZONE_FREE(zone, element) \
 265         uma_zfree(zone, element);
 266
 267 #define SCTP_HASH_INIT(size, hashmark) hashinit_flags(size, M_PCB, hashmark, HASH_NOWAIT)
 268 #define SCTP_HASH_FREE(table, hashmark) hashdestroy(table, M_PCB, hashmark)
 269
 270 #define SCTP_M_COPYM    m_copym
 271
 272 /*
 273  * timers
 274  */
 275 #include <sys/callout.h>
 276 typedef struct callout sctp_os_timer_t;
 277
 278
 279 #define SCTP_OS_TIMER_INIT(tmr) callout_init(tmr, 1)
 280 #define SCTP_OS_TIMER_START     callout_reset
 281 #define SCTP_OS_TIMER_STOP      callout_stop
 282 #define SCTP_OS_TIMER_STOP_DRAIN callout_drain
 283 #define SCTP_OS_TIMER_PENDING   callout_pending
 284 #define SCTP_OS_TIMER_ACTIVE    callout_active
 285 #define SCTP_OS_TIMER_DEACTIVATE callout_deactivate
 286
 287 #define sctp_get_tick_count() (ticks)
 288
 289 #define SCTP_UNUSED __attribute__((unused))
 290
 291 /*
 292  * Functions
 293  */
 294 /* Mbuf manipulation and access macros  */
 295 #define SCTP_BUF_LEN(m) (m->m_len)
 296 #define SCTP_BUF_NEXT(m) (m->m_next)
 297 #define SCTP_BUF_NEXT_PKT(m) (m->m_nextpkt)
 298 #define SCTP_BUF_RESV_UF(m, size) m->m_data += size
 299 #define SCTP_BUF_AT(m, size) m->m_data + size
 300 #define SCTP_BUF_IS_EXTENDED(m) (m->m_flags & M_EXT)
 301 #define SCTP_BUF_SIZE M_SIZE
 302 #define SCTP_BUF_TYPE(m) (m->m_type)
 303 #define SCTP_BUF_RECVIF(m) (m->m_pkthdr.rcvif)
 304 #define SCTP_BUF_PREPEND        M_PREPEND
 305
 306 #define SCTP_ALIGN_TO_END(m, len) M_ALIGN(m, len)
 307
 308 /* We make it so if you have up to 4 threads
 309  * writing based on the default size of
 310  * the packet log 65 k, that would be
 311  * 4 16k packets before we would hit
 312  * a problem.
 313  */
 314 #define SCTP_PKTLOG_WRITERS_NEED_LOCK 3
 315
 316 /*************************/
 317 /*      MTU              */
 318 /*************************/
 319 #define SCTP_GATHER_MTU_FROM_IFN_INFO(ifn, ifn_index, af) ((struct ifnet *)ifn)->if_mtu
 320 #define SCTP_GATHER_MTU_FROM_ROUTE(sctp_ifa, sa, rt) ((uint32_t)((rt != NULL) ? rt->rt_mtu : 0))
 321 #define SCTP_GATHER_MTU_FROM_INTFC(sctp_ifn) ((sctp_ifn->ifn_p != NULL) ? ((struct ifnet *)(sctp_ifn->ifn_p))->if_mtu : 0)
 322 #define SCTP_SET_MTU_OF_ROUTE(sa, rt, mtu) do { \
 323                                               if (rt != NULL) \
 324                                                  rt->rt_mtu = mtu; \
 325                                            } while(0)
 326
 327 /* (de-)register interface event notifications */
 328 #define SCTP_REGISTER_INTERFACE(ifhandle, af)
 329 #define SCTP_DEREGISTER_INTERFACE(ifhandle, af)
 330
 331
 332 /*************************/
 333 /* These are for logging */
 334 /*************************/
 335 /* return the base ext data pointer */
 336 #define SCTP_BUF_EXTEND_BASE(m) (m->m_ext.ext_buf)
 337  /* return the refcnt of the data pointer */
 338 #define SCTP_BUF_EXTEND_REFCNT(m) (*m->m_ext.ext_cnt)
 339 /* return any buffer related flags, this is
 340  * used beyond logging for apple only.
 341  */
 342 #define SCTP_BUF_GET_FLAGS(m) (m->m_flags)
 343
 344 /* For BSD this just accesses the M_PKTHDR length
 345  * so it operates on an mbuf with hdr flag. Other
 346  * O/S's may have separate packet header and mbuf
 347  * chain pointers.. thus the macro.
 348  */
 349 #define SCTP_HEADER_TO_CHAIN(m) (m)
 350 #define SCTP_DETACH_HEADER_FROM_CHAIN(m)
 351 #define SCTP_HEADER_LEN(m) ((m)->m_pkthdr.len)
 352 #define SCTP_GET_HEADER_FOR_OUTPUT(o_pak) 0
 353 #define SCTP_RELEASE_HEADER(m)
 354 #define SCTP_RELEASE_PKT(m)     sctp_m_freem(m)
 355 #define SCTP_ENABLE_UDP_CSUM(m) do { \
 356                                         m->m_pkthdr.csum_flags = CSUM_UDP; \
 357                                         m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum); \
 358                                 } while (0)
 359
 360 #define SCTP_GET_PKT_VRFID(m, vrf_id)  ((vrf_id = SCTP_DEFAULT_VRFID) != SCTP_DEFAULT_VRFID)
 361
 362
 363
 364 /* Attach the chain of data into the sendable packet. */
 365 #define SCTP_ATTACH_CHAIN(pak, m, packet_length) do { \
 366                                                  pak = m; \
 367                                                  pak->m_pkthdr.len = packet_length; \
 368                          } while(0)
 369
 370 /* Other m_pkthdr type things */
 371 #define SCTP_IS_IT_BROADCAST(dst, m) ((m->m_flags & M_PKTHDR) ? in_broadcast(dst, m->m_pkthdr.rcvif) : 0)
 372 #define SCTP_IS_IT_LOOPBACK(m) ((m->m_flags & M_PKTHDR) && ((m->m_pkthdr.rcvif == NULL) || (m->m_pkthdr.rcvif->if_type == IFT_LOOP)))
 373
 374
 375 /* This converts any input packet header
 376  * into the chain of data holders, for BSD
 377  * its a NOP.
 378  */
 379
 380 /* get the v6 hop limit */
 381 #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)));
 382
 383 /* is the endpoint v6only? */
 384 #define SCTP_IPV6_V6ONLY(inp)   (((struct inpcb *)inp)->inp_flags & IN6P_IPV6_V6ONLY)
 385 /* is the socket non-blocking? */
 386 #define SCTP_SO_IS_NBIO(so)     ((so)->so_state & SS_NBIO)
 387 #define SCTP_SET_SO_NBIO(so)    ((so)->so_state |= SS_NBIO)
 388 #define SCTP_CLEAR_SO_NBIO(so)  ((so)->so_state &= ~SS_NBIO)
 389 /* get the socket type */
 390 #define SCTP_SO_TYPE(so)        ((so)->so_type)
 391 /* Use a macro for renaming sb_cc to sb_acc.
 392  * Initially sb_ccc was used, but this broke select() when used
 393  * with SCTP sockets.
 394  */
 395 #define sb_cc sb_acc
 396 /* reserve sb space for a socket */
 397 #define SCTP_SORESERVE(so, send, recv)  soreserve(so, send, recv)
 398 /* wakeup a socket */
 399 #define SCTP_SOWAKEUP(so)       wakeup(&(so)->so_timeo)
 400 /* clear the socket buffer state */
 401 #define SCTP_SB_CLEAR(sb)       \
 402         (sb).sb_cc = 0;         \
 403         (sb).sb_mb = NULL;      \
 404         (sb).sb_mbcnt = 0;
 405
 406 #define SCTP_SB_LIMIT_RCV(so) so->so_rcv.sb_hiwat
 407 #define SCTP_SB_LIMIT_SND(so) so->so_snd.sb_hiwat
 408
 409 /*
 410  * routes, output, etc.
 411  */
 412 typedef struct route sctp_route_t;
 413 typedef struct rtentry sctp_rtentry_t;
 414
 415 #define SCTP_RTALLOC(ro, vrf_id, fibnum) \
 416         rtalloc_ign_fib((struct route *)ro, 0UL, fibnum)
 417
 418 /* Future zero copy wakeup/send  function */
 419 #define SCTP_ZERO_COPY_EVENT(inp, so)
 420 /* This is re-pulse ourselves for sendbuf */
 421 #define SCTP_ZERO_COPY_SENDQ_EVENT(inp, so)
 422
 423 /*
 424  * SCTP protocol specific mbuf flags.
 425  */
 426 #define M_NOTIFICATION          M_PROTO1        /* SCTP notification */
 427
 428 /*
 429  * IP output routines
 430  */
 431 #define SCTP_IP_OUTPUT(result, o_pak, ro, stcb, vrf_id) \
 432 { \
 433         int o_flgs = IP_RAWOUTPUT; \
 434         struct sctp_tcb *local_stcb = stcb; \
 435         if (local_stcb && \
 436             local_stcb->sctp_ep && \
 437             local_stcb->sctp_ep->sctp_socket) \
 438                 o_flgs |= local_stcb->sctp_ep->sctp_socket->so_options & SO_DONTROUTE; \
 439         m_clrprotoflags(o_pak); \
 440         result = ip_output(o_pak, NULL, ro, o_flgs, 0, NULL); \
 441 }
 442
 443 #define SCTP_IP6_OUTPUT(result, o_pak, ro, ifp, stcb, vrf_id) \
 444 { \
 445         struct sctp_tcb *local_stcb = stcb; \
 446         m_clrprotoflags(o_pak); \
 447         if (local_stcb && local_stcb->sctp_ep) \
 448                 result = ip6_output(o_pak, \
 449                                     ((struct in6pcb *)(local_stcb->sctp_ep))->in6p_outputopts, \
 450                                     (ro), 0, 0, ifp, NULL); \
 451         else \
 452                 result = ip6_output(o_pak, NULL, (ro), 0, 0, ifp, NULL); \
 453 }
 454
 455 struct mbuf *
 456 sctp_get_mbuf_for_msg(unsigned int space_needed,
 457     int want_header, int how, int allonebuf, int type);
 458
 459
 460 /*
 461  * SCTP AUTH
 462  */
 463 #define SCTP_READ_RANDOM(buf, len)      read_random(buf, len)
 464
 465 /* map standard crypto API names */
 466 #define SCTP_SHA1_CTX           SHA1_CTX
 467 #define SCTP_SHA1_INIT          SHA1Init
 468 #define SCTP_SHA1_UPDATE        SHA1Update
 469 #define SCTP_SHA1_FINAL(x,y)    SHA1Final((caddr_t)x, y)
 470
 471 #define SCTP_SHA256_CTX         SHA256_CTX
 472 #define SCTP_SHA256_INIT        SHA256_Init
 473 #define SCTP_SHA256_UPDATE      SHA256_Update
 474 #define SCTP_SHA256_FINAL(x,y)  SHA256_Final((caddr_t)x, y)
 475
 476 #endif
 477
 478 #define SCTP_DECREMENT_AND_CHECK_REFCOUNT(addr) (atomic_fetchadd_int(addr, -1) == 1)
 479 #if defined(INVARIANTS)
 480 #define SCTP_SAVE_ATOMIC_DECREMENT(addr, val) \
 481 { \
 482         int32_t oldval; \
 483         oldval = atomic_fetchadd_int(addr, -val); \
 484         if (oldval < val) { \
 485                 panic("Counter goes negative"); \
 486         } \
 487 }
 488 #else
 489 #define SCTP_SAVE_ATOMIC_DECREMENT(addr, val) \
 490 { \
 491         int32_t oldval; \
 492         oldval = atomic_fetchadd_int(addr, -val); \
 493         if (oldval < val) { \
 494                 *addr = 0; \
 495         } \
 496 }
 497 #endif