1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2008 5 * Swinburne University of Technology, Melbourne, Australia. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS "AS IS" AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 /* 30 * Alias_sctp forms part of the libalias kernel module to handle 31 * Network Address Translation (NAT) for the SCTP protocol. 32 * 33 * This software was developed by David A. Hayes and Jason But 34 * 35 * The design is outlined in CAIA technical report number 080618A 36 * (D. Hayes and J. But, "Alias_sctp Version 0.1: SCTP NAT implementation in IPFW") 37 * 38 * Development is part of the CAIA SONATA project, 39 * proposed by Jason But and Grenville Armitage: 40 * http://caia.swin.edu.au/urp/sonata/ 41 * 42 * 43 * This project has been made possible in part by a grant from 44 * the Cisco University Research Program Fund at Community 45 * Foundation Silicon Valley. 46 * 47 */ 48 /** @mainpage 49 * Alias_sctp is part of the SONATA (http://caia.swin.edu.au/urp/sonata) project 50 * to develop and release a BSD licensed implementation of a Network Address 51 * Translation (NAT) module that supports the Stream Control Transmission 52 * Protocol (SCTP). 53 * 54 * Traditional address and port number look ups are inadequate for SCTP's 55 * operation due to both processing requirements and issues with multi-homing. 56 * Alias_sctp integrates with FreeBSD's ipfw/libalias NAT system. 57 * 58 * Version 0.2 features include: 59 * - Support for global multi-homing 60 * - Support for ASCONF modification from Internet Draft 61 * (draft-stewart-behave-sctpnat-04, R. Stewart and M. Tuexen, "Stream control 62 * transmission protocol (SCTP) network address translation," Jul. 2008) to 63 * provide support for multi-homed privately addressed hosts 64 * - Support for forwarding of T-flagged packets 65 * - Generation and delivery of AbortM/ErrorM packets upon detection of NAT 66 * collisions 67 * - Per-port forwarding rules 68 * - Dynamically controllable logging and statistics 69 * - Dynamic management of timers 70 * - Dynamic control of hash-table size 71 */ 72 73 /* $FreeBSD$ */ 74 75 #ifdef _KERNEL 76 #include <machine/stdarg.h> 77 #include <sys/param.h> 78 #include <sys/gsb_crc32.h> 79 #include <sys/systm.h> 80 #include <sys/kernel.h> 81 #include <sys/module.h> 82 #include <sys/syslog.h> 83 #include <netinet/libalias/alias_sctp.h> 84 #include <netinet/libalias/alias.h> 85 #include <netinet/libalias/alias_local.h> 86 #include <netinet/sctp_crc32.h> 87 #include <machine/in_cksum.h> 88 #else 89 #include "alias_sctp.h" 90 #include <arpa/inet.h> 91 #include "alias.h" 92 #include "alias_local.h" 93 #include <machine/in_cksum.h> 94 #include <sys/libkern.h> 95 #endif //#ifdef _KERNEL 96 97 /* ---------------------------------------------------------------------- 98 * FUNCTION PROTOTYPES 99 * ---------------------------------------------------------------------- 100 */ 101 /* Packet Parsing Functions */ 102 static int sctp_PktParser(struct libalias *la, int direction, struct ip *pip, 103 struct sctp_nat_msg *sm, struct sctp_nat_assoc **passoc); 104 static int GetAsconfVtags(struct libalias *la, struct sctp_nat_msg *sm, 105 uint32_t *l_vtag, uint32_t *g_vtag, int direction); 106 static int IsASCONFack(struct libalias *la, struct sctp_nat_msg *sm, int direction); 107 108 static void AddGlobalIPAddresses(struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int direction); 109 static int Add_Global_Address_to_List(struct sctp_nat_assoc *assoc, struct sctp_GlobalAddress *G_addr); 110 static void RmGlobalIPAddresses(struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int direction); 111 static int IsADDorDEL(struct libalias *la, struct sctp_nat_msg *sm, int direction); 112 113 /* State Machine Functions */ 114 static int ProcessSctpMsg(struct libalias *la, int direction, \ 115 struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc); 116 117 static int ID_process(struct libalias *la, int direction,\ 118 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm); 119 static int INi_process(struct libalias *la, int direction,\ 120 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm); 121 static int INa_process(struct libalias *la, int direction,\ 122 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm); 123 static int UP_process(struct libalias *la, int direction,\ 124 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm); 125 static int CL_process(struct libalias *la, int direction,\ 126 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm); 127 static void TxAbortErrorM(struct libalias *la, struct sctp_nat_msg *sm,\ 128 struct sctp_nat_assoc *assoc, int sndrply, int direction); 129 130 /* Hash Table Functions */ 131 static struct sctp_nat_assoc * 132 FindSctpLocal(struct libalias *la, struct in_addr l_addr, struct in_addr g_addr, uint32_t l_vtag, uint16_t l_port, uint16_t g_port); 133 static struct sctp_nat_assoc * 134 FindSctpGlobal(struct libalias *la, struct in_addr g_addr, uint32_t g_vtag, uint16_t g_port, uint16_t l_port, int *partial_match); 135 static struct sctp_nat_assoc * 136 FindSctpGlobalClash(struct libalias *la, struct sctp_nat_assoc *Cassoc); 137 static struct sctp_nat_assoc * 138 FindSctpLocalT(struct libalias *la, struct in_addr g_addr, uint32_t l_vtag, uint16_t g_port, uint16_t l_port); 139 static struct sctp_nat_assoc * 140 FindSctpGlobalT(struct libalias *la, struct in_addr g_addr, uint32_t g_vtag, uint16_t l_port, uint16_t g_port); 141 142 static int AddSctpAssocLocal(struct libalias *la, struct sctp_nat_assoc *assoc, struct in_addr g_addr); 143 static int AddSctpAssocGlobal(struct libalias *la, struct sctp_nat_assoc *assoc); 144 static void RmSctpAssoc(struct libalias *la, struct sctp_nat_assoc *assoc); 145 static void freeGlobalAddressList(struct sctp_nat_assoc *assoc); 146 147 /* Timer Queue Functions */ 148 static void sctp_AddTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc); 149 static void sctp_RmTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc); 150 static void sctp_ResetTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc, int newexp); 151 void sctp_CheckTimers(struct libalias *la); 152 153 /* Logging Functions */ 154 static void logsctperror(char *errormsg, uint32_t vtag, int error, int direction); 155 static void logsctpparse(int direction, struct sctp_nat_msg *sm); 156 static void logsctpassoc(struct sctp_nat_assoc *assoc, char *s); 157 static void logTimerQ(struct libalias *la); 158 static void logSctpGlobal(struct libalias *la); 159 static void logSctpLocal(struct libalias *la); 160 #ifdef _KERNEL 161 static void SctpAliasLog(const char *format, ...); 162 #endif 163 164 /** @defgroup external External code changes and modifications 165 * 166 * Some changes have been made to files external to alias_sctp.(c|h). These 167 * changes are primarily due to code needing to call static functions within 168 * those files or to perform extra functionality that can only be performed 169 * within these files. 170 */ 171 /** @ingroup external 172 * @brief Log current statistics for the libalias instance 173 * 174 * This function is defined in alias_db.c, since it calls static functions in 175 * this file 176 * 177 * Calls the higher level ShowAliasStats() in alias_db.c which logs all current 178 * statistics about the libalias instance - including SCTP statistics 179 * 180 * @param la Pointer to the libalias instance 181 */ 182 void SctpShowAliasStats(struct libalias *la); 183 184 #ifdef _KERNEL 185 186 static MALLOC_DEFINE(M_SCTPNAT, "sctpnat", "sctp nat dbs"); 187 /* Use kernel allocator. */ 188 #ifdef _SYS_MALLOC_H_ 189 #define sn_malloc(x) malloc(x, M_SCTPNAT, M_NOWAIT|M_ZERO) 190 #define sn_calloc(n,x) mallocarray((n), (x), M_SCTPNAT, M_NOWAIT|M_ZERO) 191 #define sn_free(x) free(x, M_SCTPNAT) 192 #endif// #ifdef _SYS_MALLOC_H_ 193 194 #else //#ifdef _KERNEL 195 #define sn_malloc(x) malloc(x) 196 #define sn_calloc(n, x) calloc(n, x) 197 #define sn_free(x) free(x) 198 199 #endif //#ifdef _KERNEL 200 201 /** @defgroup packet_parser SCTP Packet Parsing 202 * 203 * Macros to: 204 * - Return pointers to the first and next SCTP chunks within an SCTP Packet 205 * - Define possible return values of the packet parsing process 206 * - SCTP message types for storing in the sctp_nat_msg structure @{ 207 */ 208 209 #define SN_SCTP_FIRSTCHUNK(sctphead) (struct sctp_chunkhdr *)(((char *)sctphead) + sizeof(struct sctphdr)) 210 /**< Returns a pointer to the first chunk in an SCTP packet given a pointer to the SCTP header */ 211 212 #define SN_SCTP_NEXTCHUNK(chunkhead) (struct sctp_chunkhdr *)(((char *)chunkhead) + SCTP_SIZE32(ntohs(chunkhead->chunk_length))) 213 /**< Returns a pointer to the next chunk in an SCTP packet given a pointer to the current chunk */ 214 215 #define SN_SCTP_NEXTPARAM(param) (struct sctp_paramhdr *)(((char *)param) + SCTP_SIZE32(ntohs(param->param_length))) 216 /**< Returns a pointer to the next parameter in an SCTP packet given a pointer to the current parameter */ 217 218 #define SN_MIN_CHUNK_SIZE 4 /**< Smallest possible SCTP chunk size in bytes */ 219 #define SN_MIN_PARAM_SIZE 4 /**< Smallest possible SCTP param size in bytes */ 220 #define SN_VTAG_PARAM_SIZE 12 /**< Size of SCTP ASCONF vtag param in bytes */ 221 #define SN_ASCONFACK_PARAM_SIZE 8 /**< Size of SCTP ASCONF ACK param in bytes */ 222 223 /* Packet parsing return codes */ 224 #define SN_PARSE_OK 0 /**< Packet parsed for SCTP messages */ 225 #define SN_PARSE_ERROR_IPSHL 1 /**< Packet parsing error - IP and SCTP common header len */ 226 #define SN_PARSE_ERROR_AS_MALLOC 2 /**< Packet parsing error - assoc malloc */ 227 #define SN_PARSE_ERROR_CHHL 3 /**< Packet parsing error - Chunk header len */ 228 #define SN_PARSE_ERROR_DIR 4 /**< Packet parsing error - Direction */ 229 #define SN_PARSE_ERROR_VTAG 5 /**< Packet parsing error - Vtag */ 230 #define SN_PARSE_ERROR_CHUNK 6 /**< Packet parsing error - Chunk */ 231 #define SN_PARSE_ERROR_PORT 7 /**< Packet parsing error - Port=0 */ 232 #define SN_PARSE_ERROR_LOOKUP 8 /**< Packet parsing error - Lookup */ 233 #define SN_PARSE_ERROR_PARTIALLOOKUP 9 /**< Packet parsing error - partial lookup only found */ 234 #define SN_PARSE_ERROR_LOOKUP_ABORT 10 /**< Packet parsing error - Lookup - but abort packet */ 235 236 /* Alias_sctp performs its processing based on a number of key messages */ 237 #define SN_SCTP_ABORT 0x0000 /**< a packet containing an ABORT chunk */ 238 #define SN_SCTP_INIT 0x0001 /**< a packet containing an INIT chunk */ 239 #define SN_SCTP_INITACK 0x0002 /**< a packet containing an INIT-ACK chunk */ 240 #define SN_SCTP_SHUTCOMP 0x0010 /**< a packet containing a SHUTDOWN-COMPLETE chunk */ 241 #define SN_SCTP_SHUTACK 0x0020 /**< a packet containing a SHUTDOWN-ACK chunk */ 242 #define SN_SCTP_ASCONF 0x0100 /**< a packet containing an ASCONF chunk */ 243 #define SN_SCTP_ASCONFACK 0x0200 /**< a packet containing an ASCONF-ACK chunk */ 244 #define SN_SCTP_OTHER 0xFFFF /**< a packet containing a chunk that is not of interest */ 245 /** @} 246 * @defgroup state_machine SCTP NAT State Machine 247 * 248 * Defines the various states an association can be within the NAT @{ 249 */ 250 #define SN_ID 0x0000 /**< Idle state */ 251 #define SN_INi 0x0010 /**< Initialising, waiting for InitAck state */ 252 #define SN_INa 0x0020 /**< Initialising, waiting for AddIpAck state */ 253 #define SN_UP 0x0100 /**< Association in UP state */ 254 #define SN_CL 0x1000 /**< Closing state */ 255 #define SN_RM 0x2000 /**< Removing state */ 256 /** @} 257 * @defgroup Logging Logging Functionality 258 * 259 * Define various log levels and a macro to call specified log functions only if 260 * the current log level (sysctl_log_level) matches the specified level @{ 261 */ 262 #define SN_LOG_LOW 0 263 #define SN_LOG_EVENT 1 264 #define SN_LOG_INFO 2 265 #define SN_LOG_DETAIL 3 266 #define SN_LOG_DEBUG 4 267 #define SN_LOG_DEBUG_MAX 5 268 269 #define SN_LOG(level, action) if (sysctl_log_level >= level) { action; } /**< Perform log action ONLY if the current log level meets the specified log level */ 270 /** @} 271 * @defgroup Hash Hash Table Macros and Functions 272 * 273 * Defines minimum/maximum/default values for the hash table size @{ 274 */ 275 #define SN_MIN_HASH_SIZE 101 /**< Minimum hash table size (set to stop users choosing stupid values) */ 276 #define SN_MAX_HASH_SIZE 1000001 /**< Maximum hash table size (NB must be less than max int) */ 277 #define SN_DEFAULT_HASH_SIZE 2003 /**< A reasonable default size for the hash tables */ 278 279 #define SN_LOCAL_TBL 0x01 /**< assoc in local table */ 280 #define SN_GLOBAL_TBL 0x02 /**< assoc in global table */ 281 #define SN_BOTH_TBL 0x03 /**< assoc in both tables */ 282 #define SN_WAIT_TOLOCAL 0x10 /**< assoc waiting for TOLOCAL asconf ACK*/ 283 #define SN_WAIT_TOGLOBAL 0x20 /**< assoc waiting for TOLOCAL asconf ACK*/ 284 #define SN_NULL_TBL 0x00 /**< assoc in No table */ 285 #define SN_MAX_GLOBAL_ADDRESSES 100 /**< absolute maximum global address count*/ 286 287 #define SN_ADD_OK 0 /**< Association added to the table */ 288 #define SN_ADD_CLASH 1 /**< Clash when trying to add the assoc. info to the table */ 289 290 #define SN_TABLE_HASH(vtag, port, size) (((u_int) vtag + (u_int) port) % (u_int) size) /**< Calculate the hash table lookup position */ 291 /** @} 292 * @defgroup Timer Timer Queue Macros and Functions 293 * 294 * Timer macros set minimum/maximum timeout values and calculate timer expiry 295 * times for the provided libalias instance @{ 296 */ 297 #define SN_MIN_TIMER 1 298 #define SN_MAX_TIMER 600 299 #define SN_TIMER_QUEUE_SIZE SN_MAX_TIMER+2 300 301 #define SN_I_T(la) (LibAliasTime + sysctl_init_timer) /**< INIT State expiration time in seconds */ 302 #define SN_U_T(la) (LibAliasTime + sysctl_up_timer) /**< UP State expiration time in seconds */ 303 #define SN_C_T(la) (LibAliasTime + sysctl_shutdown_timer) /**< CL State expiration time in seconds */ 304 #define SN_X_T(la) (LibAliasTime + sysctl_holddown_timer) /**< Wait after a shutdown complete in seconds */ 305 /** @} 306 * @defgroup sysctl SysCtl Variable and callback function declarations 307 * 308 * Sysctl variables to modify NAT functionality in real-time along with associated functions 309 * to manage modifications to the sysctl variables @{ 310 */ 311 312 /* Callbacks */ 313 int sysctl_chg_loglevel(SYSCTL_HANDLER_ARGS); 314 int sysctl_chg_timer(SYSCTL_HANDLER_ARGS); 315 int sysctl_chg_hashtable_size(SYSCTL_HANDLER_ARGS); 316 int sysctl_chg_error_on_ootb(SYSCTL_HANDLER_ARGS); 317 int sysctl_chg_accept_global_ootb_addip(SYSCTL_HANDLER_ARGS); 318 int sysctl_chg_initialising_chunk_proc_limit(SYSCTL_HANDLER_ARGS); 319 int sysctl_chg_chunk_proc_limit(SYSCTL_HANDLER_ARGS); 320 int sysctl_chg_param_proc_limit(SYSCTL_HANDLER_ARGS); 321 int sysctl_chg_track_global_addresses(SYSCTL_HANDLER_ARGS); 322 323 /* Sysctl variables */ 324 /** @brief net.inet.ip.alias.sctp.log_level */ 325 static u_int sysctl_log_level = 0; /**< Stores the current level of logging */ 326 /** @brief net.inet.ip.alias.sctp.init_timer */ 327 static u_int sysctl_init_timer = 15; /**< Seconds to hold an association in the table waiting for an INIT-ACK or AddIP-ACK */ 328 /** @brief net.inet.ip.alias.sctp.up_timer */ 329 static u_int sysctl_up_timer = 300; /**< Seconds to hold an association in the table while no packets are transmitted */ 330 /** @brief net.inet.ip.alias.sctp.shutdown_timer */ 331 static u_int sysctl_shutdown_timer = 15; /**< Seconds to hold an association in the table waiting for a SHUTDOWN-COMPLETE */ 332 /** @brief net.inet.ip.alias.sctp.holddown_timer */ 333 static u_int sysctl_holddown_timer = 0; /**< Seconds to hold an association in the table after it has been shutdown (to allow for lost SHUTDOWN-COMPLETEs) */ 334 /** @brief net.inet.ip.alias.sctp.hashtable_size */ 335 static u_int sysctl_hashtable_size = SN_DEFAULT_HASH_SIZE; /**< Sets the hash table size for any NEW NAT instances (existing instances retain their existing Hash Table */ 336 /** @brief net.inet.ip.alias.sctp.error_on_ootb */ 337 static u_int sysctl_error_on_ootb = 1; /**< NAT response to receipt of OOTB packet 338 (0 - No response, 1 - NAT will send ErrorM only to local side, 339 2 - NAT will send local ErrorM and global ErrorM if there was a partial association match 340 3 - NAT will send ErrorM to both local and global) */ 341 /** @brief net.inet.ip.alias.sctp.accept_global_ootb_addip */ 342 static u_int sysctl_accept_global_ootb_addip = 0; /**<NAT responset to receipt of global OOTB AddIP (0 - No response, 1 - NAT will accept OOTB global AddIP messages for processing (Security risk)) */ 343 /** @brief net.inet.ip.alias.sctp.initialising_chunk_proc_limit */ 344 static u_int sysctl_initialising_chunk_proc_limit = 2; /**< A limit on the number of chunks that should be searched if there is no matching association (DoS prevention) */ 345 /** @brief net.inet.ip.alias.sctp.param_proc_limit */ 346 static u_int sysctl_chunk_proc_limit = 5; /**< A limit on the number of chunks that should be searched (DoS prevention) */ 347 /** @brief net.inet.ip.alias.sctp.param_proc_limit */ 348 static u_int sysctl_param_proc_limit = 25; /**< A limit on the number of parameters (in chunks) that should be searched (DoS prevention) */ 349 /** @brief net.inet.ip.alias.sctp.track_global_addresses */ 350 static u_int sysctl_track_global_addresses = 0; /**< Configures the global address tracking option within the NAT (0 - Global tracking is disabled, > 0 - enables tracking but limits the number of global IP addresses to this value) 351 If set to >=1 the NAT will track that many global IP addresses. This may reduce look up table conflicts, but increases processing */ 352 353 #define SN_NO_ERROR_ON_OOTB 0 /**< Send no errorM on out of the blue packets */ 354 #define SN_LOCAL_ERROR_ON_OOTB 1 /**< Send only local errorM on out of the blue packets */ 355 #define SN_LOCALandPARTIAL_ERROR_ON_OOTB 2 /**< Send local errorM and global errorM for out of the blue packets only if partial match found */ 356 #define SN_ERROR_ON_OOTB 3 /**< Send errorM on out of the blue packets */ 357 358 #ifdef SYSCTL_NODE 359 360 SYSCTL_DECL(_net_inet); 361 SYSCTL_DECL(_net_inet_ip); 362 SYSCTL_DECL(_net_inet_ip_alias); 363 364 static SYSCTL_NODE(_net_inet_ip_alias, OID_AUTO, sctp, 365 CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 366 "SCTP NAT"); 367 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, log_level, 368 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 369 &sysctl_log_level, 0, sysctl_chg_loglevel, "IU", 370 "Level of detail (0 - default, 1 - event, 2 - info, 3 - detail, 4 - debug, 5 - max debug)"); 371 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, init_timer, 372 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 373 &sysctl_init_timer, 0, sysctl_chg_timer, "IU", 374 "Timeout value (s) while waiting for (INIT-ACK|AddIP-ACK)"); 375 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, up_timer, 376 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 377 &sysctl_up_timer, 0, sysctl_chg_timer, "IU", 378 "Timeout value (s) to keep an association up with no traffic"); 379 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, shutdown_timer, 380 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 381 &sysctl_shutdown_timer, 0, sysctl_chg_timer, "IU", 382 "Timeout value (s) while waiting for SHUTDOWN-COMPLETE"); 383 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, holddown_timer, 384 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 385 &sysctl_holddown_timer, 0, sysctl_chg_timer, "IU", 386 "Hold association in table for this many seconds after receiving a SHUTDOWN-COMPLETE"); 387 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, hashtable_size, 388 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 389 &sysctl_hashtable_size, 0, sysctl_chg_hashtable_size, "IU", 390 "Size of hash tables used for NAT lookups (100 < prime_number > 1000001)"); 391 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, error_on_ootb, 392 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 393 &sysctl_error_on_ootb, 0, sysctl_chg_error_on_ootb, "IU", 394 "ErrorM sent on receipt of ootb packet:\n\t0 - none,\n" 395 "\t1 - to local only,\n" 396 "\t2 - to local and global if a partial association match,\n" 397 "\t3 - to local and global (DoS risk)"); 398 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, accept_global_ootb_addip, 399 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 400 &sysctl_accept_global_ootb_addip, 0, sysctl_chg_accept_global_ootb_addip, "IU", 401 "NAT response to receipt of global OOTB AddIP:\n" 402 "\t0 - No response,\n" 403 "\t1 - NAT will accept OOTB global AddIP messages for processing (Security risk)"); 404 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, initialising_chunk_proc_limit, 405 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 406 &sysctl_initialising_chunk_proc_limit, 0, 407 sysctl_chg_initialising_chunk_proc_limit, "IU", 408 "Number of chunks that should be processed if there is no current " 409 "association found:\n\t > 0 (A high value is a DoS risk)"); 410 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, chunk_proc_limit, 411 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 412 &sysctl_chunk_proc_limit, 0, sysctl_chg_chunk_proc_limit, "IU", 413 "Number of chunks that should be processed to find key chunk:\n" 414 "\t>= initialising_chunk_proc_limit (A high value is a DoS risk)"); 415 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, param_proc_limit, 416 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 417 &sysctl_param_proc_limit, 0, sysctl_chg_param_proc_limit, "IU", 418 "Number of parameters (in a chunk) that should be processed to find key " 419 "parameters:\n\t> 1 (A high value is a DoS risk)"); 420 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, track_global_addresses, 421 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 422 &sysctl_track_global_addresses, 0, sysctl_chg_track_global_addresses, "IU", 423 "Configures the global address tracking option within the NAT:\n" 424 "\t0 - Global tracking is disabled,\n" 425 "\t> 0 - enables tracking but limits the number of global IP addresses to this value"); 426 427 #endif /* SYSCTL_NODE */ 428 /** @} 429 * @ingroup sysctl 430 * @brief sysctl callback for changing net.inet.ip.fw.sctp.log_level 431 * 432 * Updates the variable sysctl_log_level to the provided value and ensures 433 * it is in the valid range (SN_LOG_LOW -> SN_LOG_DEBUG) 434 */ 435 int sysctl_chg_loglevel(SYSCTL_HANDLER_ARGS) 436 { 437 u_int level = *(u_int *)arg1; 438 int error; 439 440 error = sysctl_handle_int(oidp, &level, 0, req); 441 if (error) 442 return (error); 443 444 level = (level > SN_LOG_DEBUG_MAX) ? (SN_LOG_DEBUG_MAX) : (level); 445 level = (level < SN_LOG_LOW) ? (SN_LOG_LOW) : (level); 446 sysctl_log_level = level; 447 return (0); 448 } 449 450 /** @ingroup sysctl 451 * @brief sysctl callback for changing net.inet.ip.fw.sctp.(init_timer|up_timer|shutdown_timer) 452 * 453 * Updates the timer-based sysctl variables. The new values are sanity-checked 454 * to make sure that they are within the range SN_MIN_TIMER-SN_MAX_TIMER. The 455 * holddown timer is allowed to be 0 456 */ 457 int sysctl_chg_timer(SYSCTL_HANDLER_ARGS) 458 { 459 u_int timer = *(u_int *)arg1; 460 int error; 461 462 error = sysctl_handle_int(oidp, &timer, 0, req); 463 if (error) 464 return (error); 465 466 timer = (timer > SN_MAX_TIMER) ? (SN_MAX_TIMER) : (timer); 467 468 if (((u_int *)arg1) != &sysctl_holddown_timer) { 469 timer = (timer < SN_MIN_TIMER) ? (SN_MIN_TIMER) : (timer); 470 } 471 472 *(u_int *)arg1 = timer; 473 474 return (0); 475 } 476 477 /** @ingroup sysctl 478 * @brief sysctl callback for changing net.inet.ip.alias.sctp.hashtable_size 479 * 480 * Updates the hashtable_size sysctl variable. The new value should be a prime 481 * number. We sanity check to ensure that the size is within the range 482 * SN_MIN_HASH_SIZE-SN_MAX_HASH_SIZE. We then check the provided number to see 483 * if it is prime. We approximate by checking that (2,3,5,7,11) are not factors, 484 * incrementing the user provided value until we find a suitable number. 485 */ 486 int sysctl_chg_hashtable_size(SYSCTL_HANDLER_ARGS) 487 { 488 u_int size = *(u_int *)arg1; 489 int error; 490 491 error = sysctl_handle_int(oidp, &size, 0, req); 492 if (error) 493 return (error); 494 495 size = (size < SN_MIN_HASH_SIZE) ? (SN_MIN_HASH_SIZE) : ((size > SN_MAX_HASH_SIZE) ? (SN_MAX_HASH_SIZE) : (size)); 496 497 size |= 0x00000001; /* make odd */ 498 499 for (;(((size % 3) == 0) || ((size % 5) == 0) || ((size % 7) == 0) || ((size % 11) == 0)); size+=2); 500 sysctl_hashtable_size = size; 501 502 return (0); 503 } 504 505 /** @ingroup sysctl 506 * @brief sysctl callback for changing net.inet.ip.alias.sctp.error_on_ootb 507 * 508 * Updates the error_on_clash sysctl variable. 509 * If set to 0, no ErrorM will be sent if there is a look up table clash 510 * If set to 1, an ErrorM is sent only to the local side 511 * If set to 2, an ErrorM is sent to the local side and global side if there is 512 * a partial association match 513 * If set to 3, an ErrorM is sent to both local and global sides (DoS) risk. 514 */ 515 int sysctl_chg_error_on_ootb(SYSCTL_HANDLER_ARGS) 516 { 517 u_int flag = *(u_int *)arg1; 518 int error; 519 520 error = sysctl_handle_int(oidp, &flag, 0, req); 521 if (error) 522 return (error); 523 524 sysctl_error_on_ootb = (flag > SN_ERROR_ON_OOTB) ? SN_ERROR_ON_OOTB: flag; 525 526 return (0); 527 } 528 529 /** @ingroup sysctl 530 * @brief sysctl callback for changing net.inet.ip.alias.sctp.accept_global_ootb_addip 531 * 532 * If set to 1 the NAT will accept ootb global addip messages for processing (Security risk) 533 * Default is 0, only responding to local ootb AddIP messages 534 */ 535 int sysctl_chg_accept_global_ootb_addip(SYSCTL_HANDLER_ARGS) 536 { 537 u_int flag = *(u_int *)arg1; 538 int error; 539 540 error = sysctl_handle_int(oidp, &flag, 0, req); 541 if (error) 542 return (error); 543 544 sysctl_accept_global_ootb_addip = (flag == 1) ? 1: 0; 545 546 return (0); 547 } 548 549 /** @ingroup sysctl 550 * @brief sysctl callback for changing net.inet.ip.alias.sctp.initialising_chunk_proc_limit 551 * 552 * Updates the initialising_chunk_proc_limit sysctl variable. Number of chunks 553 * that should be processed if there is no current association found: > 0 (A 554 * high value is a DoS risk) 555 */ 556 int sysctl_chg_initialising_chunk_proc_limit(SYSCTL_HANDLER_ARGS) 557 { 558 u_int proclimit = *(u_int *)arg1; 559 int error; 560 561 error = sysctl_handle_int(oidp, &proclimit, 0, req); 562 if (error) 563 return (error); 564 565 sysctl_initialising_chunk_proc_limit = (proclimit < 1) ? 1: proclimit; 566 sysctl_chunk_proc_limit = 567 (sysctl_chunk_proc_limit < sysctl_initialising_chunk_proc_limit) ? sysctl_initialising_chunk_proc_limit : sysctl_chunk_proc_limit; 568 569 return (0); 570 } 571 572 /** @ingroup sysctl 573 * @brief sysctl callback for changing net.inet.ip.alias.sctp.chunk_proc_limit 574 * 575 * Updates the chunk_proc_limit sysctl variable. 576 * Number of chunks that should be processed to find key chunk: 577 * >= initialising_chunk_proc_limit (A high value is a DoS risk) 578 */ 579 int sysctl_chg_chunk_proc_limit(SYSCTL_HANDLER_ARGS) 580 { 581 u_int proclimit = *(u_int *)arg1; 582 int error; 583 584 error = sysctl_handle_int(oidp, &proclimit, 0, req); 585 if (error) 586 return (error); 587 588 sysctl_chunk_proc_limit = 589 (proclimit < sysctl_initialising_chunk_proc_limit) ? sysctl_initialising_chunk_proc_limit : proclimit; 590 591 return (0); 592 } 593 594 /** @ingroup sysctl 595 * @brief sysctl callback for changing net.inet.ip.alias.sctp.param_proc_limit 596 * 597 * Updates the param_proc_limit sysctl variable. 598 * Number of parameters that should be processed to find key parameters: 599 * > 1 (A high value is a DoS risk) 600 */ 601 int sysctl_chg_param_proc_limit(SYSCTL_HANDLER_ARGS) 602 { 603 u_int proclimit = *(u_int *)arg1; 604 int error; 605 606 error = sysctl_handle_int(oidp, &proclimit, 0, req); 607 if (error) 608 return (error); 609 610 sysctl_param_proc_limit = 611 (proclimit < 2) ? 2 : proclimit; 612 613 return (0); 614 } 615 616 /** @ingroup sysctl 617 * @brief sysctl callback for changing net.inet.ip.alias.sctp.track_global_addresses 618 * 619 *Configures the global address tracking option within the NAT (0 - Global 620 *tracking is disabled, > 0 - enables tracking but limits the number of global 621 *IP addresses to this value) 622 */ 623 int sysctl_chg_track_global_addresses(SYSCTL_HANDLER_ARGS) 624 { 625 u_int num_to_track = *(u_int *)arg1; 626 int error; 627 628 error = sysctl_handle_int(oidp, &num_to_track, 0, req); 629 if (error) 630 return (error); 631 632 sysctl_track_global_addresses = (num_to_track > SN_MAX_GLOBAL_ADDRESSES) ? SN_MAX_GLOBAL_ADDRESSES : num_to_track; 633 634 return (0); 635 } 636 637 /* ---------------------------------------------------------------------- 638 * CODE BEGINS HERE 639 * ---------------------------------------------------------------------- 640 */ 641 /** 642 * @brief Initialises the SCTP NAT Implementation 643 * 644 * Creates the look-up tables and the timer queue and initialises all state 645 * variables 646 * 647 * @param la Pointer to the relevant libalias instance 648 */ 649 void 650 AliasSctpInit(struct libalias *la) 651 { 652 /* Initialise association tables*/ 653 int i; 654 la->sctpNatTableSize = sysctl_hashtable_size; 655 SN_LOG(SN_LOG_EVENT, 656 SctpAliasLog("Initialising SCTP NAT Instance (hash_table_size:%d)\n", la->sctpNatTableSize)); 657 la->sctpTableLocal = sn_calloc(la->sctpNatTableSize, sizeof(struct sctpNatTableL)); 658 la->sctpTableGlobal = sn_calloc(la->sctpNatTableSize, sizeof(struct sctpNatTableG)); 659 la->sctpNatTimer.TimerQ = sn_calloc(SN_TIMER_QUEUE_SIZE, sizeof(struct sctpTimerQ)); 660 /* Initialise hash table */ 661 for (i = 0; i < la->sctpNatTableSize; i++) { 662 LIST_INIT(&la->sctpTableLocal[i]); 663 LIST_INIT(&la->sctpTableGlobal[i]); 664 } 665 666 /* Initialise circular timer Q*/ 667 for (i = 0; i < SN_TIMER_QUEUE_SIZE; i++) 668 LIST_INIT(&la->sctpNatTimer.TimerQ[i]); 669 #ifdef _KERNEL 670 la->sctpNatTimer.loc_time=time_uptime; /* LibAliasTime is not set yet */ 671 #else 672 la->sctpNatTimer.loc_time=LibAliasTime; 673 #endif 674 la->sctpNatTimer.cur_loc = 0; 675 la->sctpLinkCount = 0; 676 } 677 678 /** 679 * @brief Cleans-up the SCTP NAT Implementation prior to unloading 680 * 681 * Removes all entries from the timer queue, freeing associations as it goes. 682 * We then free memory allocated to the look-up tables and the time queue 683 * 684 * NOTE: We do not need to traverse the look-up tables as each association 685 * will always have an entry in the timer queue, freeing this memory 686 * once will free all memory allocated to entries in the look-up tables 687 * 688 * @param la Pointer to the relevant libalias instance 689 */ 690 void 691 AliasSctpTerm(struct libalias *la) 692 { 693 struct sctp_nat_assoc *assoc1, *assoc2; 694 int i; 695 696 LIBALIAS_LOCK_ASSERT(la); 697 SN_LOG(SN_LOG_EVENT, 698 SctpAliasLog("Removing SCTP NAT Instance\n")); 699 for (i = 0; i < SN_TIMER_QUEUE_SIZE; i++) { 700 assoc1 = LIST_FIRST(&la->sctpNatTimer.TimerQ[i]); 701 while (assoc1 != NULL) { 702 freeGlobalAddressList(assoc1); 703 assoc2 = LIST_NEXT(assoc1, timer_Q); 704 sn_free(assoc1); 705 assoc1 = assoc2; 706 } 707 } 708 709 sn_free(la->sctpTableLocal); 710 sn_free(la->sctpTableGlobal); 711 sn_free(la->sctpNatTimer.TimerQ); 712 } 713 714 /** 715 * @brief Handles SCTP packets passed from libalias 716 * 717 * This function needs to actually NAT/drop packets and possibly create and 718 * send AbortM or ErrorM packets in response. The process involves: 719 * - Validating the direction parameter passed by the caller 720 * - Checking and handling any expired timers for the NAT 721 * - Calling sctp_PktParser() to parse the packet 722 * - Call ProcessSctpMsg() to decide the appropriate outcome and to update 723 * the NAT tables 724 * - Based on the return code either: 725 * - NAT the packet 726 * - Construct and send an ErrorM|AbortM packet 727 * - Mark the association for removal from the tables 728 * - Potentially remove the association from all lookup tables 729 * - Return the appropriate result to libalias 730 * 731 * @param la Pointer to the relevant libalias instance 732 * @param pip Pointer to IP packet to process 733 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 734 * 735 * @return PKT_ALIAS_OK | PKT_ALIAS_IGNORE | PKT_ALIAS_ERROR 736 */ 737 int 738 SctpAlias(struct libalias *la, struct ip *pip, int direction) 739 { 740 int rtnval; 741 struct sctp_nat_msg msg; 742 struct sctp_nat_assoc *assoc = NULL; 743 744 if ((direction != SN_TO_LOCAL) && (direction != SN_TO_GLOBAL)) { 745 SctpAliasLog("ERROR: Invalid direction\n"); 746 return (PKT_ALIAS_ERROR); 747 } 748 749 sctp_CheckTimers(la); /* Check timers */ 750 751 /* Parse the packet */ 752 rtnval = sctp_PktParser(la, direction, pip, &msg, &assoc); //using *char (change to mbuf when get code from paolo) 753 switch (rtnval) { 754 case SN_PARSE_OK: 755 break; 756 case SN_PARSE_ERROR_CHHL: 757 /* Not an error if there is a chunk length parsing error and this is a fragmented packet */ 758 if (ntohs(pip->ip_off) & IP_MF) { 759 rtnval = SN_PARSE_OK; 760 break; 761 } 762 SN_LOG(SN_LOG_EVENT, 763 logsctperror("SN_PARSE_ERROR", msg.sctp_hdr->v_tag, rtnval, direction)); 764 return (PKT_ALIAS_ERROR); 765 case SN_PARSE_ERROR_PARTIALLOOKUP: 766 if (sysctl_error_on_ootb > SN_LOCALandPARTIAL_ERROR_ON_OOTB) { 767 SN_LOG(SN_LOG_EVENT, 768 logsctperror("SN_PARSE_ERROR", msg.sctp_hdr->v_tag, rtnval, direction)); 769 return (PKT_ALIAS_ERROR); 770 } 771 case SN_PARSE_ERROR_LOOKUP: 772 if (sysctl_error_on_ootb == SN_ERROR_ON_OOTB || 773 (sysctl_error_on_ootb == SN_LOCALandPARTIAL_ERROR_ON_OOTB && direction == SN_TO_LOCAL) || 774 (sysctl_error_on_ootb == SN_LOCAL_ERROR_ON_OOTB && direction == SN_TO_GLOBAL)) { 775 TxAbortErrorM(la, &msg, assoc, SN_REFLECT_ERROR, direction); /*NB assoc=NULL */ 776 return (PKT_ALIAS_RESPOND); 777 } 778 default: 779 SN_LOG(SN_LOG_EVENT, 780 logsctperror("SN_PARSE_ERROR", msg.sctp_hdr->v_tag, rtnval, direction)); 781 return (PKT_ALIAS_ERROR); 782 } 783 784 SN_LOG(SN_LOG_DETAIL, 785 logsctpassoc(assoc, "*"); 786 logsctpparse(direction, &msg); 787 ); 788 789 /* Process the SCTP message */ 790 rtnval = ProcessSctpMsg(la, direction, &msg, assoc); 791 792 SN_LOG(SN_LOG_DEBUG_MAX, 793 logsctpassoc(assoc, "-"); 794 logSctpLocal(la); 795 logSctpGlobal(la); 796 ); 797 SN_LOG(SN_LOG_DEBUG, logTimerQ(la)); 798 799 switch (rtnval) { 800 case SN_NAT_PKT: 801 switch (direction) { 802 case SN_TO_LOCAL: 803 DifferentialChecksum(&(msg.ip_hdr->ip_sum), 804 &(assoc->l_addr), &(msg.ip_hdr->ip_dst), 2); 805 msg.ip_hdr->ip_dst = assoc->l_addr; /* change dst address to local address*/ 806 break; 807 case SN_TO_GLOBAL: 808 DifferentialChecksum(&(msg.ip_hdr->ip_sum), 809 &(assoc->a_addr), &(msg.ip_hdr->ip_src), 2); 810 msg.ip_hdr->ip_src = assoc->a_addr; /* change src to alias addr*/ 811 break; 812 default: 813 rtnval = SN_DROP_PKT; /* shouldn't get here, but if it does drop packet */ 814 SN_LOG(SN_LOG_LOW, logsctperror("ERROR: Invalid direction", msg.sctp_hdr->v_tag, rtnval, direction)); 815 break; 816 } 817 break; 818 case SN_DROP_PKT: 819 SN_LOG(SN_LOG_DETAIL, logsctperror("SN_DROP_PKT", msg.sctp_hdr->v_tag, rtnval, direction)); 820 break; 821 case SN_REPLY_ABORT: 822 case SN_REPLY_ERROR: 823 case SN_SEND_ABORT: 824 TxAbortErrorM(la, &msg, assoc, rtnval, direction); 825 break; 826 default: 827 // big error, remove association and go to idle and write log messages 828 SN_LOG(SN_LOG_LOW, logsctperror("SN_PROCESSING_ERROR", msg.sctp_hdr->v_tag, rtnval, direction)); 829 assoc->state = SN_RM;/* Mark for removal*/ 830 break; 831 } 832 833 /* Remove association if tagged for removal */ 834 if (assoc->state == SN_RM) { 835 if (assoc->TableRegister) { 836 sctp_RmTimeOut(la, assoc); 837 RmSctpAssoc(la, assoc); 838 } 839 LIBALIAS_LOCK_ASSERT(la); 840 freeGlobalAddressList(assoc); 841 sn_free(assoc); 842 } 843 switch (rtnval) { 844 case SN_NAT_PKT: 845 return (PKT_ALIAS_OK); 846 case SN_SEND_ABORT: 847 return (PKT_ALIAS_OK); 848 case SN_REPLY_ABORT: 849 case SN_REPLY_ERROR: 850 case SN_REFLECT_ERROR: 851 return (PKT_ALIAS_RESPOND); 852 case SN_DROP_PKT: 853 default: 854 return (PKT_ALIAS_ERROR); 855 } 856 } 857 858 /** 859 * @brief Send an AbortM or ErrorM 860 * 861 * We construct the new SCTP packet to send in place of the existing packet we 862 * have been asked to NAT. This function can only be called if the original 863 * packet was successfully parsed as a valid SCTP packet. 864 * 865 * An AbortM (without cause) packet is the smallest SCTP packet available and as 866 * such there is always space in the existing packet buffer to fit the AbortM 867 * packet. An ErrorM packet is 4 bytes longer than the (the error cause is not 868 * optional). An ErrorM is sent in response to an AddIP when the Vtag/address 869 * combination, if added, will produce a conflict in the association look up 870 * tables. It may also be used for an unexpected packet - a packet with no 871 * matching association in the NAT table and we are requesting an AddIP so we 872 * can add it. The smallest valid SCTP packet while the association is in an 873 * up-state is a Heartbeat packet, which is big enough to be transformed to an 874 * ErrorM. 875 * 876 * We create a temporary character array to store the packet as we are constructing 877 * it. We then populate the array with appropriate values based on: 878 * - Packet type (AbortM | ErrorM) 879 * - Initial packet direction (SN_TO_LOCAL | SN_TO_GLOBAL) 880 * - NAT response (Send packet | Reply packet) 881 * 882 * Once complete, we copy the contents of the temporary packet over the original 883 * SCTP packet we were asked to NAT 884 * 885 * @param la Pointer to the relevant libalias instance 886 * @param sm Pointer to sctp message information 887 * @param assoc Pointer to current association details 888 * @param sndrply SN_SEND_ABORT | SN_REPLY_ABORT | SN_REPLY_ERROR 889 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 890 */ 891 static uint32_t 892 local_sctp_finalize_crc32(uint32_t crc32c) 893 { 894 /* This routine is duplicated from SCTP 895 * we need to do that since it MAY be that SCTP 896 * is NOT compiled into the kernel. The CRC32C routines 897 * however are always available in libkern. 898 */ 899 uint32_t result; 900 #if BYTE_ORDER == BIG_ENDIAN 901 uint8_t byte0, byte1, byte2, byte3; 902 903 #endif 904 /* Complement the result */ 905 result = ~crc32c; 906 #if BYTE_ORDER == BIG_ENDIAN 907 /* 908 * For BIG-ENDIAN.. aka Motorola byte order the result is in 909 * little-endian form. So we must manually swap the bytes. Then we 910 * can call htonl() which does nothing... 911 */ 912 byte0 = result & 0x000000ff; 913 byte1 = (result >> 8) & 0x000000ff; 914 byte2 = (result >> 16) & 0x000000ff; 915 byte3 = (result >> 24) & 0x000000ff; 916 crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3); 917 #else 918 /* 919 * For INTEL platforms the result comes out in network order. No 920 * htonl is required or the swap above. So we optimize out both the 921 * htonl and the manual swap above. 922 */ 923 crc32c = result; 924 #endif 925 return (crc32c); 926 } 927 928 static void 929 TxAbortErrorM(struct libalias *la, struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int sndrply, int direction) 930 { 931 int sctp_size = sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_error_cause); 932 int ip_size = sizeof(struct ip) + sctp_size; 933 int include_error_cause = 1; 934 char tmp_ip[ip_size]; 935 char addrbuf[INET_ADDRSTRLEN]; 936 937 if (ntohs(sm->ip_hdr->ip_len) < ip_size) { /* short packet, cannot send error cause */ 938 include_error_cause = 0; 939 ip_size = ip_size - sizeof(struct sctp_error_cause); 940 sctp_size = sctp_size - sizeof(struct sctp_error_cause); 941 } 942 /* Assign header pointers packet */ 943 struct ip* ip = (struct ip *) tmp_ip; 944 struct sctphdr* sctp_hdr = (struct sctphdr *) ((char *) ip + sizeof(*ip)); 945 struct sctp_chunkhdr* chunk_hdr = (struct sctp_chunkhdr *) ((char *) sctp_hdr + sizeof(*sctp_hdr)); 946 struct sctp_error_cause* error_cause = (struct sctp_error_cause *) ((char *) chunk_hdr + sizeof(*chunk_hdr)); 947 948 /* construct ip header */ 949 ip->ip_v = sm->ip_hdr->ip_v; 950 ip->ip_hl = 5; /* 5*32 bit words */ 951 ip->ip_tos = 0; 952 ip->ip_len = htons(ip_size); 953 ip->ip_id = sm->ip_hdr->ip_id; 954 ip->ip_off = 0; 955 ip->ip_ttl = 255; 956 ip->ip_p = IPPROTO_SCTP; 957 /* 958 The definitions below should be removed when they make it into the SCTP stack 959 */ 960 #define SCTP_MIDDLEBOX_FLAG 0x02 961 #define SCTP_NAT_TABLE_COLLISION 0x00b0 962 #define SCTP_MISSING_NAT 0x00b1 963 chunk_hdr->chunk_type = (sndrply & SN_TX_ABORT) ? SCTP_ABORT_ASSOCIATION : SCTP_OPERATION_ERROR; 964 chunk_hdr->chunk_flags = SCTP_MIDDLEBOX_FLAG; 965 if (include_error_cause) { 966 error_cause->code = htons((sndrply & SN_REFLECT_ERROR) ? SCTP_MISSING_NAT : SCTP_NAT_TABLE_COLLISION); 967 error_cause->length = htons(sizeof(struct sctp_error_cause)); 968 chunk_hdr->chunk_length = htons(sizeof(*chunk_hdr) + sizeof(struct sctp_error_cause)); 969 } else { 970 chunk_hdr->chunk_length = htons(sizeof(*chunk_hdr)); 971 } 972 973 /* set specific values */ 974 switch (sndrply) { 975 case SN_REFLECT_ERROR: 976 chunk_hdr->chunk_flags |= SCTP_HAD_NO_TCB; /* set Tbit */ 977 sctp_hdr->v_tag = sm->sctp_hdr->v_tag; 978 break; 979 case SN_REPLY_ERROR: 980 sctp_hdr->v_tag = (direction == SN_TO_LOCAL) ? assoc->g_vtag : assoc->l_vtag ; 981 break; 982 case SN_SEND_ABORT: 983 sctp_hdr->v_tag = sm->sctp_hdr->v_tag; 984 break; 985 case SN_REPLY_ABORT: 986 sctp_hdr->v_tag = sm->sctpchnk.Init->initiate_tag; 987 break; 988 } 989 990 /* Set send/reply values */ 991 if (sndrply == SN_SEND_ABORT) { /*pass through NAT */ 992 ip->ip_src = (direction == SN_TO_LOCAL) ? sm->ip_hdr->ip_src : assoc->a_addr; 993 ip->ip_dst = (direction == SN_TO_LOCAL) ? assoc->l_addr : sm->ip_hdr->ip_dst; 994 sctp_hdr->src_port = sm->sctp_hdr->src_port; 995 sctp_hdr->dest_port = sm->sctp_hdr->dest_port; 996 } else { /* reply and reflect */ 997 ip->ip_src = sm->ip_hdr->ip_dst; 998 ip->ip_dst = sm->ip_hdr->ip_src; 999 sctp_hdr->src_port = sm->sctp_hdr->dest_port; 1000 sctp_hdr->dest_port = sm->sctp_hdr->src_port; 1001 } 1002 1003 /* Calculate IP header checksum */ 1004 ip->ip_sum = in_cksum_hdr(ip); 1005 1006 /* calculate SCTP header CRC32 */ 1007 sctp_hdr->checksum = 0; 1008 sctp_hdr->checksum = local_sctp_finalize_crc32(calculate_crc32c(0xffffffff, (unsigned char *) sctp_hdr, sctp_size)); 1009 1010 memcpy(sm->ip_hdr, ip, ip_size); 1011 1012 SN_LOG(SN_LOG_EVENT,SctpAliasLog("%s %s 0x%x (->%s:%u vtag=0x%x crc=0x%x)\n", 1013 ((sndrply == SN_SEND_ABORT) ? "Sending" : "Replying"), 1014 ((sndrply & SN_TX_ERROR) ? "ErrorM" : "AbortM"), 1015 (include_error_cause ? ntohs(error_cause->code) : 0), 1016 inet_ntoa_r(ip->ip_dst, INET_NTOA_BUF(addrbuf)), 1017 ntohs(sctp_hdr->dest_port), 1018 ntohl(sctp_hdr->v_tag), ntohl(sctp_hdr->checksum))); 1019 } 1020 1021 /* ---------------------------------------------------------------------- 1022 * PACKET PARSER CODE 1023 * ---------------------------------------------------------------------- 1024 */ 1025 /** @addtogroup packet_parser 1026 * 1027 * These functions parse the SCTP packet and fill a sctp_nat_msg structure 1028 * with the parsed contents. 1029 */ 1030 /** @ingroup packet_parser 1031 * @brief Parses SCTP packets for the key SCTP chunk that will be processed 1032 * 1033 * This module parses SCTP packets for the key SCTP chunk that will be processed 1034 * The module completes the sctp_nat_msg structure and either retrieves the 1035 * relevant (existing) stored association from the Hash Tables or creates a new 1036 * association entity with state SN_ID 1037 * 1038 * @param la Pointer to the relevant libalias instance 1039 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1040 * @param pip 1041 * @param sm Pointer to sctp message information 1042 * @param passoc Pointer to the association this SCTP Message belongs to 1043 * 1044 * @return SN_PARSE_OK | SN_PARSE_ERROR_* 1045 */ 1046 static int 1047 sctp_PktParser(struct libalias *la, int direction, struct ip *pip, 1048 struct sctp_nat_msg *sm, struct sctp_nat_assoc **passoc) 1049 //sctp_PktParser(int direction, struct mbuf *ipak, int ip_hdr_len,struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc) 1050 { 1051 struct sctphdr *sctp_hdr; 1052 struct sctp_chunkhdr *chunk_hdr; 1053 struct sctp_paramhdr *param_hdr; 1054 struct in_addr ipv4addr; 1055 int bytes_left; /* bytes left in ip packet */ 1056 int chunk_length; 1057 int chunk_count; 1058 int partial_match = 0; 1059 // mbuf *mp; 1060 // int mlen; 1061 1062 // mlen = SCTP_HEADER_LEN(i_pak); 1063 // mp = SCTP_HEADER_TO_CHAIN(i_pak); /* does nothing in bsd since header and chain not separate */ 1064 1065 /* 1066 * Note, that if the VTag is zero, it must be an INIT 1067 * Also, I am only interested in the content of INIT and ADDIP chunks 1068 */ 1069 1070 // no mbuf stuff from Paolo yet so ... 1071 sm->ip_hdr = pip; 1072 /* remove ip header length from the bytes_left */ 1073 bytes_left = ntohs(pip->ip_len) - (pip->ip_hl << 2); 1074 1075 /* Check SCTP header length and move to first chunk */ 1076 if (bytes_left < sizeof(struct sctphdr)) { 1077 sm->sctp_hdr = NULL; 1078 return (SN_PARSE_ERROR_IPSHL); /* packet not long enough*/ 1079 } 1080 1081 sm->sctp_hdr = sctp_hdr = (struct sctphdr *) ip_next(pip); 1082 bytes_left -= sizeof(struct sctphdr); 1083 1084 /* Check for valid ports (zero valued ports would find partially initialised associations */ 1085 if (sctp_hdr->src_port == 0 || sctp_hdr->dest_port == 0) 1086 return (SN_PARSE_ERROR_PORT); 1087 1088 /* Check length of first chunk */ 1089 if (bytes_left < SN_MIN_CHUNK_SIZE) /* malformed chunk - could cause endless loop*/ 1090 return (SN_PARSE_ERROR_CHHL); /* packet not long enough for this chunk */ 1091 1092 /* First chunk */ 1093 chunk_hdr = SN_SCTP_FIRSTCHUNK(sctp_hdr); 1094 1095 chunk_length = SCTP_SIZE32(ntohs(chunk_hdr->chunk_length)); 1096 if ((chunk_length < SN_MIN_CHUNK_SIZE) || (chunk_length > bytes_left)) /* malformed chunk - could cause endless loop*/ 1097 return (SN_PARSE_ERROR_CHHL); 1098 1099 if ((chunk_hdr->chunk_flags & SCTP_HAD_NO_TCB) && 1100 ((chunk_hdr->chunk_type == SCTP_ABORT_ASSOCIATION) || 1101 (chunk_hdr->chunk_type == SCTP_SHUTDOWN_COMPLETE))) { 1102 /* T-Bit set */ 1103 if (direction == SN_TO_LOCAL) 1104 *passoc = FindSctpGlobalT(la, pip->ip_src, sctp_hdr->v_tag, sctp_hdr->dest_port, sctp_hdr->src_port); 1105 else 1106 *passoc = FindSctpLocalT(la, pip->ip_dst, sctp_hdr->v_tag, sctp_hdr->dest_port, sctp_hdr->src_port); 1107 } else { 1108 /* Proper v_tag settings */ 1109 if (direction == SN_TO_LOCAL) 1110 *passoc = FindSctpGlobal(la, pip->ip_src, sctp_hdr->v_tag, sctp_hdr->src_port, sctp_hdr->dest_port, &partial_match); 1111 else 1112 *passoc = FindSctpLocal(la, pip->ip_src, pip->ip_dst, sctp_hdr->v_tag, sctp_hdr->src_port, sctp_hdr->dest_port); 1113 } 1114 1115 chunk_count = 1; 1116 /* Real packet parsing occurs below */ 1117 sm->msg = SN_SCTP_OTHER;/* Initialise to largest value*/ 1118 sm->chunk_length = 0; /* only care about length for key chunks */ 1119 while (IS_SCTP_CONTROL(chunk_hdr)) { 1120 switch (chunk_hdr->chunk_type) { 1121 case SCTP_INITIATION: 1122 if (chunk_length < sizeof(struct sctp_init_chunk)) /* malformed chunk*/ 1123 return (SN_PARSE_ERROR_CHHL); 1124 sm->msg = SN_SCTP_INIT; 1125 sm->sctpchnk.Init = (struct sctp_init *) ((char *) chunk_hdr + sizeof(struct sctp_chunkhdr)); 1126 sm->chunk_length = chunk_length; 1127 /* if no existing association, create a new one */ 1128 if (*passoc == NULL) { 1129 if (sctp_hdr->v_tag == 0) { //Init requires vtag=0 1130 *passoc = (struct sctp_nat_assoc *) sn_malloc(sizeof(struct sctp_nat_assoc)); 1131 if (*passoc == NULL) {/* out of resources */ 1132 return (SN_PARSE_ERROR_AS_MALLOC); 1133 } 1134 /* Initialize association - sn_malloc initializes memory to zeros */ 1135 (*passoc)->state = SN_ID; 1136 LIST_INIT(&((*passoc)->Gaddr)); /* always initialise to avoid memory problems */ 1137 (*passoc)->TableRegister = SN_NULL_TBL; 1138 return (SN_PARSE_OK); 1139 } 1140 return (SN_PARSE_ERROR_VTAG); 1141 } 1142 return (SN_PARSE_ERROR_LOOKUP); 1143 case SCTP_INITIATION_ACK: 1144 if (chunk_length < sizeof(struct sctp_init_ack_chunk)) /* malformed chunk*/ 1145 return (SN_PARSE_ERROR_CHHL); 1146 sm->msg = SN_SCTP_INITACK; 1147 sm->sctpchnk.InitAck = (struct sctp_init_ack *) ((char *) chunk_hdr + sizeof(struct sctp_chunkhdr)); 1148 sm->chunk_length = chunk_length; 1149 return ((*passoc == NULL) ? (SN_PARSE_ERROR_LOOKUP) : (SN_PARSE_OK)); 1150 case SCTP_ABORT_ASSOCIATION: /* access only minimum sized chunk */ 1151 sm->msg = SN_SCTP_ABORT; 1152 sm->chunk_length = chunk_length; 1153 return ((*passoc == NULL) ? (SN_PARSE_ERROR_LOOKUP_ABORT) : (SN_PARSE_OK)); 1154 case SCTP_SHUTDOWN_ACK: 1155 if (chunk_length < sizeof(struct sctp_shutdown_ack_chunk)) /* malformed chunk*/ 1156 return (SN_PARSE_ERROR_CHHL); 1157 if (sm->msg > SN_SCTP_SHUTACK) { 1158 sm->msg = SN_SCTP_SHUTACK; 1159 sm->chunk_length = chunk_length; 1160 } 1161 break; 1162 case SCTP_SHUTDOWN_COMPLETE: /* minimum sized chunk */ 1163 if (sm->msg > SN_SCTP_SHUTCOMP) { 1164 sm->msg = SN_SCTP_SHUTCOMP; 1165 sm->chunk_length = chunk_length; 1166 } 1167 return ((*passoc == NULL) ? (SN_PARSE_ERROR_LOOKUP) : (SN_PARSE_OK)); 1168 case SCTP_ASCONF: 1169 if (sm->msg > SN_SCTP_ASCONF) { 1170 if (chunk_length < (sizeof(struct sctp_asconf_chunk) + sizeof(struct sctp_ipv4addr_param))) /* malformed chunk*/ 1171 return (SN_PARSE_ERROR_CHHL); 1172 //leave parameter searching to later, if required 1173 param_hdr = (struct sctp_paramhdr *) ((char *) chunk_hdr + sizeof(struct sctp_asconf_chunk)); /*compulsory IP parameter*/ 1174 if (ntohs(param_hdr->param_type) == SCTP_IPV4_ADDRESS) { 1175 if ((*passoc == NULL) && (direction == SN_TO_LOCAL)) { /* AddIP with no association */ 1176 /* try look up with the ASCONF packet's alternative address */ 1177 ipv4addr.s_addr = ((struct sctp_ipv4addr_param *) param_hdr)->addr; 1178 *passoc = FindSctpGlobal(la, ipv4addr, sctp_hdr->v_tag, sctp_hdr->src_port, sctp_hdr->dest_port, &partial_match); 1179 } 1180 param_hdr = (struct sctp_paramhdr *) 1181 ((char *) param_hdr + sizeof(struct sctp_ipv4addr_param)); /*asconf's compulsory address parameter */ 1182 sm->chunk_length = chunk_length - sizeof(struct sctp_asconf_chunk) - sizeof(struct sctp_ipv4addr_param); /* rest of chunk */ 1183 } else { 1184 if (chunk_length < (sizeof(struct sctp_asconf_chunk) + sizeof(struct sctp_ipv6addr_param))) /* malformed chunk*/ 1185 return (SN_PARSE_ERROR_CHHL); 1186 param_hdr = (struct sctp_paramhdr *) 1187 ((char *) param_hdr + sizeof(struct sctp_ipv6addr_param)); /*asconf's compulsory address parameter */ 1188 sm->chunk_length = chunk_length - sizeof(struct sctp_asconf_chunk) - sizeof(struct sctp_ipv6addr_param); /* rest of chunk */ 1189 } 1190 sm->msg = SN_SCTP_ASCONF; 1191 sm->sctpchnk.Asconf = param_hdr; 1192 1193 if (*passoc == NULL) { /* AddIP with no association */ 1194 *passoc = (struct sctp_nat_assoc *) sn_malloc(sizeof(struct sctp_nat_assoc)); 1195 if (*passoc == NULL) {/* out of resources */ 1196 return (SN_PARSE_ERROR_AS_MALLOC); 1197 } 1198 /* Initialize association - sn_malloc initializes memory to zeros */ 1199 (*passoc)->state = SN_ID; 1200 LIST_INIT(&((*passoc)->Gaddr)); /* always initialise to avoid memory problems */ 1201 (*passoc)->TableRegister = SN_NULL_TBL; 1202 return (SN_PARSE_OK); 1203 } 1204 } 1205 break; 1206 case SCTP_ASCONF_ACK: 1207 if (sm->msg > SN_SCTP_ASCONFACK) { 1208 if (chunk_length < sizeof(struct sctp_asconf_ack_chunk)) /* malformed chunk*/ 1209 return (SN_PARSE_ERROR_CHHL); 1210 //leave parameter searching to later, if required 1211 param_hdr = (struct sctp_paramhdr *) ((char *) chunk_hdr 1212 + sizeof(struct sctp_asconf_ack_chunk)); 1213 sm->msg = SN_SCTP_ASCONFACK; 1214 sm->sctpchnk.Asconf = param_hdr; 1215 sm->chunk_length = chunk_length - sizeof(struct sctp_asconf_ack_chunk); 1216 } 1217 break; 1218 default: 1219 break; /* do nothing*/ 1220 } 1221 1222 /* if no association is found exit - we need to find an Init or AddIP within sysctl_initialising_chunk_proc_limit */ 1223 if ((*passoc == NULL) && (chunk_count >= sysctl_initialising_chunk_proc_limit)) 1224 return (SN_PARSE_ERROR_LOOKUP); 1225 1226 /* finished with this chunk, on to the next chunk*/ 1227 bytes_left-= chunk_length; 1228 1229 /* Is this the end of the packet ? */ 1230 if (bytes_left == 0) 1231 return (*passoc == NULL) ? (SN_PARSE_ERROR_LOOKUP) : (SN_PARSE_OK); 1232 1233 /* Are there enough bytes in packet to at least retrieve length of next chunk ? */ 1234 if (bytes_left < SN_MIN_CHUNK_SIZE) 1235 return (SN_PARSE_ERROR_CHHL); 1236 1237 chunk_hdr = SN_SCTP_NEXTCHUNK(chunk_hdr); 1238 1239 /* Is the chunk long enough to not cause endless look and are there enough bytes in packet to read the chunk ? */ 1240 chunk_length = SCTP_SIZE32(ntohs(chunk_hdr->chunk_length)); 1241 if ((chunk_length < SN_MIN_CHUNK_SIZE) || (chunk_length > bytes_left)) 1242 return (SN_PARSE_ERROR_CHHL); 1243 if (++chunk_count > sysctl_chunk_proc_limit) 1244 return (SN_PARSE_OK); /* limit for processing chunks, take what we get */ 1245 } 1246 1247 if (*passoc == NULL) 1248 return (partial_match) ? (SN_PARSE_ERROR_PARTIALLOOKUP) : (SN_PARSE_ERROR_LOOKUP); 1249 else 1250 return (SN_PARSE_OK); 1251 } 1252 1253 /** @ingroup packet_parser 1254 * @brief Extract Vtags from Asconf Chunk 1255 * 1256 * GetAsconfVtags scans an Asconf Chunk for the vtags parameter, and then 1257 * extracts the vtags. 1258 * 1259 * GetAsconfVtags is not called from within sctp_PktParser. It is called only 1260 * from within ID_process when an AddIP has been received. 1261 * 1262 * @param la Pointer to the relevant libalias instance 1263 * @param sm Pointer to sctp message information 1264 * @param l_vtag Pointer to the local vtag in the association this SCTP Message belongs to 1265 * @param g_vtag Pointer to the local vtag in the association this SCTP Message belongs to 1266 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1267 * 1268 * @return 1 - success | 0 - fail 1269 */ 1270 static int 1271 GetAsconfVtags(struct libalias *la, struct sctp_nat_msg *sm, uint32_t *l_vtag, uint32_t *g_vtag, int direction) 1272 { 1273 /* To be removed when information is in the sctp headers */ 1274 #define SCTP_VTAG_PARAM 0xC007 1275 struct sctp_vtag_param { 1276 struct sctp_paramhdr ph;/* type=SCTP_VTAG_PARAM */ 1277 uint32_t local_vtag; 1278 uint32_t remote_vtag; 1279 } __attribute__((packed)); 1280 1281 struct sctp_vtag_param *vtag_param; 1282 struct sctp_paramhdr *param; 1283 int bytes_left; 1284 int param_size; 1285 int param_count; 1286 1287 param_count = 1; 1288 param = sm->sctpchnk.Asconf; 1289 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1290 bytes_left = sm->chunk_length; 1291 /* step through Asconf parameters */ 1292 while((bytes_left >= param_size) && (bytes_left >= SN_VTAG_PARAM_SIZE)) { 1293 if (ntohs(param->param_type) == SCTP_VTAG_PARAM) { 1294 vtag_param = (struct sctp_vtag_param *) param; 1295 switch (direction) { 1296 /* The Internet draft is a little ambigious as to order of these vtags. 1297 We think it is this way around. If we are wrong, the order will need 1298 to be changed. */ 1299 case SN_TO_GLOBAL: 1300 *g_vtag = vtag_param->local_vtag; 1301 *l_vtag = vtag_param->remote_vtag; 1302 break; 1303 case SN_TO_LOCAL: 1304 *g_vtag = vtag_param->remote_vtag; 1305 *l_vtag = vtag_param->local_vtag; 1306 break; 1307 } 1308 return (1); /* found */ 1309 } 1310 1311 bytes_left -= param_size; 1312 if (bytes_left < SN_MIN_PARAM_SIZE) 1313 return (0); 1314 1315 param = SN_SCTP_NEXTPARAM(param); 1316 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1317 if (++param_count > sysctl_param_proc_limit) { 1318 SN_LOG(SN_LOG_EVENT, 1319 logsctperror("Parameter parse limit exceeded (GetAsconfVtags)", 1320 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction)); 1321 return (0); /* not found limit exceeded*/ 1322 } 1323 } 1324 return (0); /* not found */ 1325 } 1326 1327 /** @ingroup packet_parser 1328 * @brief AddGlobalIPAddresses from Init,InitAck,or AddIP packets 1329 * 1330 * AddGlobalIPAddresses scans an SCTP chunk (in sm) for Global IP addresses, and 1331 * adds them. 1332 * 1333 * @param sm Pointer to sctp message information 1334 * @param assoc Pointer to the association this SCTP Message belongs to 1335 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1336 * 1337 */ 1338 static void 1339 AddGlobalIPAddresses(struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int direction) 1340 { 1341 struct sctp_ipv4addr_param *ipv4_param; 1342 struct sctp_paramhdr *param = NULL; 1343 struct sctp_GlobalAddress *G_Addr; 1344 struct in_addr g_addr = {0}; 1345 int bytes_left = 0; 1346 int param_size; 1347 int param_count, addr_param_count = 0; 1348 1349 switch (direction) { 1350 case SN_TO_GLOBAL: /* does not contain global addresses */ 1351 g_addr = sm->ip_hdr->ip_dst; 1352 bytes_left = 0; /* force exit */ 1353 break; 1354 case SN_TO_LOCAL: 1355 g_addr = sm->ip_hdr->ip_src; 1356 param_count = 1; 1357 switch (sm->msg) { 1358 case SN_SCTP_INIT: 1359 bytes_left = sm->chunk_length - sizeof(struct sctp_init_chunk); 1360 param = (struct sctp_paramhdr *)((char *)sm->sctpchnk.Init + sizeof(struct sctp_init)); 1361 break; 1362 case SN_SCTP_INITACK: 1363 bytes_left = sm->chunk_length - sizeof(struct sctp_init_ack_chunk); 1364 param = (struct sctp_paramhdr *)((char *)sm->sctpchnk.InitAck + sizeof(struct sctp_init_ack)); 1365 break; 1366 case SN_SCTP_ASCONF: 1367 bytes_left = sm->chunk_length; 1368 param = sm->sctpchnk.Asconf; 1369 break; 1370 } 1371 } 1372 if (bytes_left >= SN_MIN_PARAM_SIZE) 1373 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1374 else 1375 param_size = bytes_left+1; /* force skip loop */ 1376 1377 if ((assoc->state == SN_ID) && ((sm->msg == SN_SCTP_INIT) || (bytes_left < SN_MIN_PARAM_SIZE))) {/* add pkt address */ 1378 G_Addr = (struct sctp_GlobalAddress *) sn_malloc(sizeof(struct sctp_GlobalAddress)); 1379 if (G_Addr == NULL) {/* out of resources */ 1380 SN_LOG(SN_LOG_EVENT, 1381 logsctperror("AddGlobalIPAddress: No resources for adding global address - revert to no tracking", 1382 sm->sctp_hdr->v_tag, 0, direction)); 1383 assoc->num_Gaddr = 0; /* don't track any more for this assoc*/ 1384 sysctl_track_global_addresses=0; 1385 return; 1386 } 1387 G_Addr->g_addr = g_addr; 1388 if (!Add_Global_Address_to_List(assoc, G_Addr)) 1389 SN_LOG(SN_LOG_EVENT, 1390 logsctperror("AddGlobalIPAddress: Address already in list", 1391 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction)); 1392 } 1393 1394 /* step through parameters */ 1395 while((bytes_left >= param_size) && (bytes_left >= sizeof(struct sctp_ipv4addr_param))) { 1396 if (assoc->num_Gaddr >= sysctl_track_global_addresses) { 1397 SN_LOG(SN_LOG_EVENT, 1398 logsctperror("AddGlobalIPAddress: Maximum Number of addresses reached", 1399 sm->sctp_hdr->v_tag, sysctl_track_global_addresses, direction)); 1400 return; 1401 } 1402 switch (ntohs(param->param_type)) { 1403 case SCTP_ADD_IP_ADDRESS: 1404 /* skip to address parameter - leave param_size so bytes left will be calculated properly*/ 1405 param = (struct sctp_paramhdr *) &((struct sctp_asconf_addrv4_param *) param)->addrp; 1406 /* FALLTHROUGH */ 1407 case SCTP_IPV4_ADDRESS: 1408 ipv4_param = (struct sctp_ipv4addr_param *) param; 1409 /* add addresses to association */ 1410 G_Addr = (struct sctp_GlobalAddress *) sn_malloc(sizeof(struct sctp_GlobalAddress)); 1411 if (G_Addr == NULL) {/* out of resources */ 1412 SN_LOG(SN_LOG_EVENT, 1413 logsctperror("AddGlobalIPAddress: No resources for adding global address - revert to no tracking", 1414 sm->sctp_hdr->v_tag, 0, direction)); 1415 assoc->num_Gaddr = 0; /* don't track any more for this assoc*/ 1416 sysctl_track_global_addresses=0; 1417 return; 1418 } 1419 /* add address */ 1420 addr_param_count++; 1421 if ((sm->msg == SN_SCTP_ASCONF) && (ipv4_param->addr == INADDR_ANY)) { /* use packet address */ 1422 G_Addr->g_addr = g_addr; 1423 if (!Add_Global_Address_to_List(assoc, G_Addr)) 1424 SN_LOG(SN_LOG_EVENT, 1425 logsctperror("AddGlobalIPAddress: Address already in list", 1426 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction)); 1427 return; /*shouldn't be any other addresses if the zero address is given*/ 1428 } else { 1429 G_Addr->g_addr.s_addr = ipv4_param->addr; 1430 if (!Add_Global_Address_to_List(assoc, G_Addr)) 1431 SN_LOG(SN_LOG_EVENT, 1432 logsctperror("AddGlobalIPAddress: Address already in list", 1433 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction)); 1434 } 1435 } 1436 1437 bytes_left -= param_size; 1438 if (bytes_left < SN_MIN_PARAM_SIZE) 1439 break; 1440 1441 param = SN_SCTP_NEXTPARAM(param); 1442 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1443 if (++param_count > sysctl_param_proc_limit) { 1444 SN_LOG(SN_LOG_EVENT, 1445 logsctperror("Parameter parse limit exceeded (AddGlobalIPAddress)", 1446 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction)); 1447 break; /* limit exceeded*/ 1448 } 1449 } 1450 if (addr_param_count == 0) { 1451 SN_LOG(SN_LOG_DETAIL, 1452 logsctperror("AddGlobalIPAddress: no address parameters to add", 1453 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction)); 1454 } 1455 } 1456 1457 /** 1458 * @brief Add_Global_Address_to_List 1459 * 1460 * Adds a global IP address to an associations address list, if it is not 1461 * already there. The first address added us usually the packet's address, and 1462 * is most likely to be used, so it is added at the beginning. Subsequent 1463 * addresses are added after this one. 1464 * 1465 * @param assoc Pointer to the association this SCTP Message belongs to 1466 * @param G_addr Pointer to the global address to add 1467 * 1468 * @return 1 - success | 0 - fail 1469 */ 1470 static int 1471 Add_Global_Address_to_List(struct sctp_nat_assoc *assoc, struct sctp_GlobalAddress *G_addr) 1472 { 1473 struct sctp_GlobalAddress *iter_G_Addr = NULL, *first_G_Addr = NULL; 1474 first_G_Addr = LIST_FIRST(&(assoc->Gaddr)); 1475 if (first_G_Addr == NULL) { 1476 LIST_INSERT_HEAD(&(assoc->Gaddr), G_addr, list_Gaddr); /* add new address to beginning of list*/ 1477 } else { 1478 LIST_FOREACH(iter_G_Addr, &(assoc->Gaddr), list_Gaddr) { 1479 if (G_addr->g_addr.s_addr == iter_G_Addr->g_addr.s_addr) 1480 return (0); /* already exists, so don't add */ 1481 } 1482 LIST_INSERT_AFTER(first_G_Addr, G_addr, list_Gaddr); /* add address to end of list*/ 1483 } 1484 assoc->num_Gaddr++; 1485 return (1); /* success */ 1486 } 1487 1488 /** @ingroup packet_parser 1489 * @brief RmGlobalIPAddresses from DelIP packets 1490 * 1491 * RmGlobalIPAddresses scans an ASCONF chunk for DelIP parameters to remove the 1492 * given Global IP addresses from the association. It will not delete the 1493 * the address if it is a list of one address. 1494 * 1495 * 1496 * @param sm Pointer to sctp message information 1497 * @param assoc Pointer to the association this SCTP Message belongs to 1498 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1499 * 1500 */ 1501 static void 1502 RmGlobalIPAddresses(struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int direction) 1503 { 1504 struct sctp_asconf_addrv4_param *asconf_ipv4_param; 1505 struct sctp_paramhdr *param; 1506 struct sctp_GlobalAddress *G_Addr, *G_Addr_tmp; 1507 int bytes_left; 1508 int param_size; 1509 int param_count; 1510 1511 bytes_left = sm->chunk_length; 1512 param_count = 1; 1513 param = sm->sctpchnk.Asconf; 1514 if (bytes_left >= SN_MIN_PARAM_SIZE) { 1515 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1516 } else { 1517 SN_LOG(SN_LOG_EVENT, 1518 logsctperror("RmGlobalIPAddress: truncated packet - cannot remove IP addresses", 1519 sm->sctp_hdr->v_tag, sysctl_track_global_addresses, direction)); 1520 return; 1521 } 1522 1523 /* step through Asconf parameters */ 1524 while((bytes_left >= param_size) && (bytes_left >= sizeof(struct sctp_ipv4addr_param))) { 1525 if (ntohs(param->param_type) == SCTP_DEL_IP_ADDRESS) { 1526 asconf_ipv4_param = (struct sctp_asconf_addrv4_param *) param; 1527 if (asconf_ipv4_param->addrp.addr == INADDR_ANY) { /* remove all bar pkt address */ 1528 LIST_FOREACH_SAFE(G_Addr, &(assoc->Gaddr), list_Gaddr, G_Addr_tmp) { 1529 if (G_Addr->g_addr.s_addr != sm->ip_hdr->ip_src.s_addr) { 1530 if (assoc->num_Gaddr > 1) { /* only delete if more than one */ 1531 LIST_REMOVE(G_Addr, list_Gaddr); 1532 sn_free(G_Addr); 1533 assoc->num_Gaddr--; 1534 } else { 1535 SN_LOG(SN_LOG_EVENT, 1536 logsctperror("RmGlobalIPAddress: Request to remove last IP address (didn't)", 1537 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction)); 1538 } 1539 } 1540 } 1541 return; /*shouldn't be any other addresses if the zero address is given*/ 1542 } else { 1543 LIST_FOREACH_SAFE(G_Addr, &(assoc->Gaddr), list_Gaddr, G_Addr_tmp) { 1544 if (G_Addr->g_addr.s_addr == asconf_ipv4_param->addrp.addr) { 1545 if (assoc->num_Gaddr > 1) { /* only delete if more than one */ 1546 LIST_REMOVE(G_Addr, list_Gaddr); 1547 sn_free(G_Addr); 1548 assoc->num_Gaddr--; 1549 break; /* Since add only adds new addresses, there should be no double entries */ 1550 } else { 1551 SN_LOG(SN_LOG_EVENT, 1552 logsctperror("RmGlobalIPAddress: Request to remove last IP address (didn't)", 1553 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction)); 1554 } 1555 } 1556 } 1557 } 1558 } 1559 bytes_left -= param_size; 1560 if (bytes_left == 0) 1561 return; 1562 else if (bytes_left < SN_MIN_PARAM_SIZE) { 1563 SN_LOG(SN_LOG_EVENT, 1564 logsctperror("RmGlobalIPAddress: truncated packet - may not have removed all IP addresses", 1565 sm->sctp_hdr->v_tag, sysctl_track_global_addresses, direction)); 1566 return; 1567 } 1568 1569 param = SN_SCTP_NEXTPARAM(param); 1570 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1571 if (++param_count > sysctl_param_proc_limit) { 1572 SN_LOG(SN_LOG_EVENT, 1573 logsctperror("Parameter parse limit exceeded (RmGlobalIPAddress)", 1574 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction)); 1575 return; /* limit exceeded*/ 1576 } 1577 } 1578 } 1579 1580 /** @ingroup packet_parser 1581 * @brief Check that ASCONF was successful 1582 * 1583 * Each ASCONF configuration parameter carries a correlation ID which should be 1584 * matched with an ASCONFack. This is difficult for a NAT, since every 1585 * association could potentially have a number of outstanding ASCONF 1586 * configuration parameters, which should only be activated on receipt of the 1587 * ACK. 1588 * 1589 * Currently we only look for an ACK when the NAT is setting up a new 1590 * association (ie AddIP for a connection that the NAT does not know about 1591 * because the original Init went through a public interface or another NAT) 1592 * Since there is currently no connection on this path, there should be no other 1593 * ASCONF configuration parameters outstanding, so we presume that if there is 1594 * an ACK that it is responding to the AddIP and activate the new association. 1595 * 1596 * @param la Pointer to the relevant libalias instance 1597 * @param sm Pointer to sctp message information 1598 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1599 * 1600 * @return 1 - success | 0 - fail 1601 */ 1602 static int 1603 IsASCONFack(struct libalias *la, struct sctp_nat_msg *sm, int direction) 1604 { 1605 struct sctp_paramhdr *param; 1606 int bytes_left; 1607 int param_size; 1608 int param_count; 1609 1610 param_count = 1; 1611 param = sm->sctpchnk.Asconf; 1612 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1613 if (param_size == 8) 1614 return (1); /*success - default acknowledgement of everything */ 1615 1616 bytes_left = sm->chunk_length; 1617 if (bytes_left < param_size) 1618 return (0); /* not found */ 1619 /* step through Asconf parameters */ 1620 while(bytes_left >= SN_ASCONFACK_PARAM_SIZE) { 1621 if (ntohs(param->param_type) == SCTP_SUCCESS_REPORT) 1622 return (1); /* success - but can't match correlation IDs - should only be one */ 1623 /* check others just in case */ 1624 bytes_left -= param_size; 1625 if (bytes_left >= SN_MIN_PARAM_SIZE) 1626 param = SN_SCTP_NEXTPARAM(param); 1627 else 1628 return (0); 1629 1630 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1631 if (bytes_left < param_size) 1632 return (0); 1633 1634 if (++param_count > sysctl_param_proc_limit) { 1635 SN_LOG(SN_LOG_EVENT, 1636 logsctperror("Parameter parse limit exceeded (IsASCONFack)", 1637 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction)); 1638 return (0); /* not found limit exceeded*/ 1639 } 1640 } 1641 return (0); /* not success */ 1642 } 1643 1644 /** @ingroup packet_parser 1645 * @brief Check to see if ASCONF contains an Add IP or Del IP parameter 1646 * 1647 * IsADDorDEL scans an ASCONF packet to see if it contains an AddIP or DelIP 1648 * parameter 1649 * 1650 * @param la Pointer to the relevant libalias instance 1651 * @param sm Pointer to sctp message information 1652 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1653 * 1654 * @return SCTP_ADD_IP_ADDRESS | SCTP_DEL_IP_ADDRESS | 0 - fail 1655 */ 1656 static int 1657 IsADDorDEL(struct libalias *la, struct sctp_nat_msg *sm, int direction) 1658 { 1659 struct sctp_paramhdr *param; 1660 int bytes_left; 1661 int param_size; 1662 int param_count; 1663 1664 param_count = 1; 1665 param = sm->sctpchnk.Asconf; 1666 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1667 1668 bytes_left = sm->chunk_length; 1669 if (bytes_left < param_size) 1670 return (0); /* not found */ 1671 /* step through Asconf parameters */ 1672 while(bytes_left >= SN_ASCONFACK_PARAM_SIZE) { 1673 if (ntohs(param->param_type) == SCTP_ADD_IP_ADDRESS) 1674 return (SCTP_ADD_IP_ADDRESS); 1675 else if (ntohs(param->param_type) == SCTP_DEL_IP_ADDRESS) 1676 return (SCTP_DEL_IP_ADDRESS); 1677 /* check others just in case */ 1678 bytes_left -= param_size; 1679 if (bytes_left >= SN_MIN_PARAM_SIZE) 1680 param = SN_SCTP_NEXTPARAM(param); 1681 else 1682 return (0); /*Neither found */ 1683 1684 param_size = SCTP_SIZE32(ntohs(param->param_length)); 1685 if (bytes_left < param_size) 1686 return (0); 1687 1688 if (++param_count > sysctl_param_proc_limit) { 1689 SN_LOG(SN_LOG_EVENT, 1690 logsctperror("Parameter parse limit exceeded IsADDorDEL)", 1691 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction)); 1692 return (0); /* not found limit exceeded*/ 1693 } 1694 } 1695 return (0); /*Neither found */ 1696 } 1697 1698 /* ---------------------------------------------------------------------- 1699 * STATE MACHINE CODE 1700 * ---------------------------------------------------------------------- 1701 */ 1702 /** @addtogroup state_machine 1703 * 1704 * The SCTP NAT State Machine functions will: 1705 * - Process an already parsed packet 1706 * - Use the existing NAT Hash Tables 1707 * - Determine the next state for the association 1708 * - Update the NAT Hash Tables and Timer Queues 1709 * - Return the appropriate action to take with the packet 1710 */ 1711 /** @ingroup state_machine 1712 * @brief Process SCTP message 1713 * 1714 * This function is the base state machine. It calls the processing engine for 1715 * each state. 1716 * 1717 * @param la Pointer to the relevant libalias instance 1718 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1719 * @param sm Pointer to sctp message information 1720 * @param assoc Pointer to the association this SCTP Message belongs to 1721 * 1722 * @return SN_DROP_PKT | SN_NAT_PKT | SN_REPLY_ABORT | SN_REPLY_ERROR | SN_PROCESSING_ERROR 1723 */ 1724 static int 1725 ProcessSctpMsg(struct libalias *la, int direction, struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc) 1726 { 1727 int rtnval; 1728 1729 switch (assoc->state) { 1730 case SN_ID: /* Idle */ 1731 rtnval = ID_process(la, direction, assoc, sm); 1732 if (rtnval != SN_NAT_PKT) { 1733 assoc->state = SN_RM;/* Mark for removal*/ 1734 } 1735 return (rtnval); 1736 case SN_INi: /* Initialising - Init */ 1737 return (INi_process(la, direction, assoc, sm)); 1738 case SN_INa: /* Initialising - AddIP */ 1739 return (INa_process(la, direction, assoc, sm)); 1740 case SN_UP: /* Association UP */ 1741 return (UP_process(la, direction, assoc, sm)); 1742 case SN_CL: /* Association Closing */ 1743 return (CL_process(la, direction, assoc, sm)); 1744 } 1745 return (SN_PROCESSING_ERROR); 1746 } 1747 1748 /** @ingroup state_machine 1749 * @brief Process SCTP message while in the Idle state 1750 * 1751 * This function looks for an Incoming INIT or AddIP message. 1752 * 1753 * All other SCTP messages are invalid when in SN_ID, and are dropped. 1754 * 1755 * @param la Pointer to the relevant libalias instance 1756 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1757 * @param sm Pointer to sctp message information 1758 * @param assoc Pointer to the association this SCTP Message belongs to 1759 * 1760 * @return SN_NAT_PKT | SN_DROP_PKT | SN_REPLY_ABORT | SN_REPLY_ERROR 1761 */ 1762 static int 1763 ID_process(struct libalias *la, int direction, struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm) 1764 { 1765 switch (sm->msg) { 1766 case SN_SCTP_ASCONF: /* a packet containing an ASCONF chunk with ADDIP */ 1767 if (!sysctl_accept_global_ootb_addip && (direction == SN_TO_LOCAL)) 1768 return (SN_DROP_PKT); 1769 /* if this Asconf packet does not contain the Vtag parameters it is of no use in Idle state */ 1770 if (!GetAsconfVtags(la, sm, &(assoc->l_vtag), &(assoc->g_vtag), direction)) 1771 return (SN_DROP_PKT); 1772 /* FALLTHROUGH */ 1773 case SN_SCTP_INIT: /* a packet containing an INIT chunk or an ASCONF AddIP */ 1774 if (sysctl_track_global_addresses) 1775 AddGlobalIPAddresses(sm, assoc, direction); 1776 switch (direction) { 1777 case SN_TO_GLOBAL: 1778 assoc->l_addr = sm->ip_hdr->ip_src; 1779 assoc->a_addr = FindAliasAddress(la, assoc->l_addr); 1780 assoc->l_port = sm->sctp_hdr->src_port; 1781 assoc->g_port = sm->sctp_hdr->dest_port; 1782 if (sm->msg == SN_SCTP_INIT) 1783 assoc->g_vtag = sm->sctpchnk.Init->initiate_tag; 1784 if (AddSctpAssocGlobal(la, assoc)) /* DB clash: need to add dst address */ 1785 return ((sm->msg == SN_SCTP_INIT) ? SN_REPLY_ABORT : SN_REPLY_ERROR); 1786 if (sm->msg == SN_SCTP_ASCONF) { 1787 if (AddSctpAssocLocal(la, assoc, sm->ip_hdr->ip_dst)) /* DB clash */ 1788 return (SN_REPLY_ERROR); 1789 assoc->TableRegister |= SN_WAIT_TOLOCAL; /* wait for tolocal ack */ 1790 } 1791 break; 1792 case SN_TO_LOCAL: 1793 assoc->l_addr = FindSctpRedirectAddress(la, sm); 1794 assoc->a_addr = sm->ip_hdr->ip_dst; 1795 assoc->l_port = sm->sctp_hdr->dest_port; 1796 assoc->g_port = sm->sctp_hdr->src_port; 1797 if (sm->msg == SN_SCTP_INIT) 1798 assoc->l_vtag = sm->sctpchnk.Init->initiate_tag; 1799 if (AddSctpAssocLocal(la, assoc, sm->ip_hdr->ip_src)) /* DB clash */ 1800 return ((sm->msg == SN_SCTP_INIT) ? SN_REPLY_ABORT : SN_REPLY_ERROR); 1801 if (sm->msg == SN_SCTP_ASCONF) { 1802 if (AddSctpAssocGlobal(la, assoc)) /* DB clash: need to add src address */ 1803 return (SN_REPLY_ERROR); 1804 assoc->TableRegister |= SN_WAIT_TOGLOBAL; /* wait for toglobal ack */ 1805 } 1806 break; 1807 } 1808 assoc->state = (sm->msg == SN_SCTP_INIT) ? SN_INi : SN_INa; 1809 assoc->exp = SN_I_T(la); 1810 sctp_AddTimeOut(la,assoc); 1811 return (SN_NAT_PKT); 1812 default: /* Any other type of SCTP message is not valid in Idle */ 1813 return (SN_DROP_PKT); 1814 } 1815 return (SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */ 1816 } 1817 1818 /** @ingroup state_machine 1819 * @brief Process SCTP message while waiting for an INIT-ACK message 1820 * 1821 * Only an INIT-ACK, resent INIT, or an ABORT SCTP packet are valid in this 1822 * state, all other packets are dropped. 1823 * 1824 * @param la Pointer to the relevant libalias instance 1825 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1826 * @param sm Pointer to sctp message information 1827 * @param assoc Pointer to the association this SCTP Message belongs to 1828 * 1829 * @return SN_NAT_PKT | SN_DROP_PKT | SN_REPLY_ABORT 1830 */ 1831 static int 1832 INi_process(struct libalias *la, int direction, struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm) 1833 { 1834 switch (sm->msg) { 1835 case SN_SCTP_INIT: /* a packet containing a retransmitted INIT chunk */ 1836 sctp_ResetTimeOut(la, assoc, SN_I_T(la)); 1837 return (SN_NAT_PKT); 1838 case SN_SCTP_INITACK: /* a packet containing an INIT-ACK chunk */ 1839 switch (direction) { 1840 case SN_TO_LOCAL: 1841 if (assoc->num_Gaddr) /*If tracking global addresses for this association */ 1842 AddGlobalIPAddresses(sm, assoc, direction); 1843 assoc->l_vtag = sm->sctpchnk.Init->initiate_tag; 1844 if (AddSctpAssocLocal(la, assoc, sm->ip_hdr->ip_src)) { /* DB clash */ 1845 assoc->state = SN_RM;/* Mark for removal*/ 1846 return (SN_SEND_ABORT); 1847 } 1848 break; 1849 case SN_TO_GLOBAL: 1850 assoc->l_addr = sm->ip_hdr->ip_src; // Only if not set in Init! * 1851 assoc->g_vtag = sm->sctpchnk.Init->initiate_tag; 1852 if (AddSctpAssocGlobal(la, assoc)) { /* DB clash */ 1853 assoc->state = SN_RM;/* Mark for removal*/ 1854 return (SN_SEND_ABORT); 1855 } 1856 break; 1857 } 1858 assoc->state = SN_UP;/* association established for NAT */ 1859 sctp_ResetTimeOut(la,assoc, SN_U_T(la)); 1860 return (SN_NAT_PKT); 1861 case SN_SCTP_ABORT: /* a packet containing an ABORT chunk */ 1862 assoc->state = SN_RM;/* Mark for removal*/ 1863 return (SN_NAT_PKT); 1864 default: 1865 return (SN_DROP_PKT); 1866 } 1867 return (SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */ 1868 } 1869 1870 /** @ingroup state_machine 1871 * @brief Process SCTP message while waiting for an AddIp-ACK message 1872 * 1873 * Only an AddIP-ACK, resent AddIP, or an ABORT message are valid, all other 1874 * SCTP packets are dropped 1875 * 1876 * @param la Pointer to the relevant libalias instance 1877 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1878 * @param sm Pointer to sctp message information 1879 * @param assoc Pointer to the association this SCTP Message belongs to 1880 * 1881 * @return SN_NAT_PKT | SN_DROP_PKT 1882 */ 1883 static int 1884 INa_process(struct libalias *la, int direction,struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm) 1885 { 1886 switch (sm->msg) { 1887 case SN_SCTP_ASCONF: /* a packet containing an ASCONF chunk*/ 1888 sctp_ResetTimeOut(la,assoc, SN_I_T(la)); 1889 return (SN_NAT_PKT); 1890 case SN_SCTP_ASCONFACK: /* a packet containing an ASCONF chunk with a ADDIP-ACK */ 1891 switch (direction) { 1892 case SN_TO_LOCAL: 1893 if (!(assoc->TableRegister & SN_WAIT_TOLOCAL)) /* wrong direction */ 1894 return (SN_DROP_PKT); 1895 break; 1896 case SN_TO_GLOBAL: 1897 if (!(assoc->TableRegister & SN_WAIT_TOGLOBAL)) /* wrong direction */ 1898 return (SN_DROP_PKT); 1899 } 1900 if (IsASCONFack(la,sm,direction)) { 1901 assoc->TableRegister &= SN_BOTH_TBL; /* remove wait flags */ 1902 assoc->state = SN_UP; /* association established for NAT */ 1903 sctp_ResetTimeOut(la,assoc, SN_U_T(la)); 1904 return (SN_NAT_PKT); 1905 } else { 1906 assoc->state = SN_RM;/* Mark for removal*/ 1907 return (SN_NAT_PKT); 1908 } 1909 case SN_SCTP_ABORT: /* a packet containing an ABORT chunk */ 1910 assoc->state = SN_RM;/* Mark for removal*/ 1911 return (SN_NAT_PKT); 1912 default: 1913 return (SN_DROP_PKT); 1914 } 1915 return (SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */ 1916 } 1917 1918 /** @ingroup state_machine 1919 * @brief Process SCTP messages while association is UP redirecting packets 1920 * 1921 * While in the SN_UP state, all packets for the particular association 1922 * are passed. Only a SHUT-ACK or an ABORT will cause a change of state. 1923 * 1924 * @param la Pointer to the relevant libalias instance 1925 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1926 * @param sm Pointer to sctp message information 1927 * @param assoc Pointer to the association this SCTP Message belongs to 1928 * 1929 * @return SN_NAT_PKT | SN_DROP_PKT 1930 */ 1931 static int 1932 UP_process(struct libalias *la, int direction, struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm) 1933 { 1934 switch (sm->msg) { 1935 case SN_SCTP_SHUTACK: /* a packet containing a SHUTDOWN-ACK chunk */ 1936 assoc->state = SN_CL; 1937 sctp_ResetTimeOut(la,assoc, SN_C_T(la)); 1938 return (SN_NAT_PKT); 1939 case SN_SCTP_ABORT: /* a packet containing an ABORT chunk */ 1940 assoc->state = SN_RM;/* Mark for removal*/ 1941 return (SN_NAT_PKT); 1942 case SN_SCTP_ASCONF: /* a packet containing an ASCONF chunk*/ 1943 if ((direction == SN_TO_LOCAL) && assoc->num_Gaddr) /*If tracking global addresses for this association & from global side */ 1944 switch (IsADDorDEL(la,sm,direction)) { 1945 case SCTP_ADD_IP_ADDRESS: 1946 AddGlobalIPAddresses(sm, assoc, direction); 1947 break; 1948 case SCTP_DEL_IP_ADDRESS: 1949 RmGlobalIPAddresses(sm, assoc, direction); 1950 break; 1951 } 1952 /* fall through to default */ 1953 default: 1954 sctp_ResetTimeOut(la,assoc, SN_U_T(la)); 1955 return (SN_NAT_PKT); /* forward packet */ 1956 } 1957 return (SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */ 1958 } 1959 1960 /** @ingroup state_machine 1961 * @brief Process SCTP message while association is in the process of closing 1962 * 1963 * This function waits for a SHUT-COMP to close the association. Depending on 1964 * the setting of sysctl_holddown_timer it may not remove the association 1965 * immediately, but leave it up until SN_X_T(la). Only SHUT-COMP, SHUT-ACK, and 1966 * ABORT packets are permitted in this state. All other packets are dropped. 1967 * 1968 * @param la Pointer to the relevant libalias instance 1969 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL 1970 * @param sm Pointer to sctp message information 1971 * @param assoc Pointer to the association this SCTP Message belongs to 1972 * 1973 * @return SN_NAT_PKT | SN_DROP_PKT 1974 */ 1975 static int 1976 CL_process(struct libalias *la, int direction,struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm) 1977 { 1978 switch (sm->msg) { 1979 case SN_SCTP_SHUTCOMP: /* a packet containing a SHUTDOWN-COMPLETE chunk */ 1980 assoc->state = SN_CL; /* Stay in Close state until timeout */ 1981 if (sysctl_holddown_timer > 0) 1982 sctp_ResetTimeOut(la, assoc, SN_X_T(la));/* allow to stay open for Tbit packets*/ 1983 else 1984 assoc->state = SN_RM;/* Mark for removal*/ 1985 return (SN_NAT_PKT); 1986 case SN_SCTP_SHUTACK: /* a packet containing a SHUTDOWN-ACK chunk */ 1987 assoc->state = SN_CL; /* Stay in Close state until timeout */ 1988 sctp_ResetTimeOut(la, assoc, SN_C_T(la)); 1989 return (SN_NAT_PKT); 1990 case SN_SCTP_ABORT: /* a packet containing an ABORT chunk */ 1991 assoc->state = SN_RM;/* Mark for removal*/ 1992 return (SN_NAT_PKT); 1993 default: 1994 return (SN_DROP_PKT); 1995 } 1996 return (SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */ 1997 } 1998 1999 /* ---------------------------------------------------------------------- 2000 * HASH TABLE CODE 2001 * ---------------------------------------------------------------------- 2002 */ 2003 /** @addtogroup Hash 2004 * 2005 * The Hash functions facilitate searching the NAT Hash Tables for associations 2006 * as well as adding/removing associations from the table(s). 2007 */ 2008 /** @ingroup Hash 2009 * @brief Find the SCTP association given the local address, port and vtag 2010 * 2011 * Searches the local look-up table for the association entry matching the 2012 * provided local <address:ports:vtag> tuple 2013 * 2014 * @param la Pointer to the relevant libalias instance 2015 * @param l_addr local address 2016 * @param g_addr global address 2017 * @param l_vtag local Vtag 2018 * @param l_port local Port 2019 * @param g_port global Port 2020 * 2021 * @return pointer to association or NULL 2022 */ 2023 static struct sctp_nat_assoc * 2024 FindSctpLocal(struct libalias *la, struct in_addr l_addr, struct in_addr g_addr, uint32_t l_vtag, uint16_t l_port, uint16_t g_port) 2025 { 2026 u_int i; 2027 struct sctp_nat_assoc *assoc = NULL; 2028 struct sctp_GlobalAddress *G_Addr = NULL; 2029 2030 if (l_vtag != 0) { /* an init packet, vtag==0 */ 2031 i = SN_TABLE_HASH(l_vtag, l_port, la->sctpNatTableSize); 2032 LIST_FOREACH(assoc, &la->sctpTableLocal[i], list_L) { 2033 if ((assoc->l_vtag == l_vtag) && (assoc->l_port == l_port) && (assoc->g_port == g_port)\ 2034 && (assoc->l_addr.s_addr == l_addr.s_addr)) { 2035 if (assoc->num_Gaddr) { 2036 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) { 2037 if (G_Addr->g_addr.s_addr == g_addr.s_addr) 2038 return (assoc); 2039 } 2040 } else { 2041 return (assoc); 2042 } 2043 } 2044 } 2045 } 2046 return (NULL); 2047 } 2048 2049 /** @ingroup Hash 2050 * @brief Check for Global Clash 2051 * 2052 * Searches the global look-up table for the association entry matching the 2053 * provided global <(addresses):ports:vtag> tuple 2054 * 2055 * @param la Pointer to the relevant libalias instance 2056 * @param Cassoc association being checked for a clash 2057 * 2058 * @return pointer to association or NULL 2059 */ 2060 static struct sctp_nat_assoc * 2061 FindSctpGlobalClash(struct libalias *la, struct sctp_nat_assoc *Cassoc) 2062 { 2063 u_int i; 2064 struct sctp_nat_assoc *assoc = NULL; 2065 struct sctp_GlobalAddress *G_Addr = NULL; 2066 struct sctp_GlobalAddress *G_AddrC = NULL; 2067 2068 if (Cassoc->g_vtag != 0) { /* an init packet, vtag==0 */ 2069 i = SN_TABLE_HASH(Cassoc->g_vtag, Cassoc->g_port, la->sctpNatTableSize); 2070 LIST_FOREACH(assoc, &la->sctpTableGlobal[i], list_G) { 2071 if ((assoc->g_vtag == Cassoc->g_vtag) && (assoc->g_port == Cassoc->g_port) && (assoc->l_port == Cassoc->l_port)) { 2072 if (assoc->num_Gaddr) { 2073 LIST_FOREACH(G_AddrC, &(Cassoc->Gaddr), list_Gaddr) { 2074 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) { 2075 if (G_Addr->g_addr.s_addr == G_AddrC->g_addr.s_addr) 2076 return (assoc); 2077 } 2078 } 2079 } else { 2080 return (assoc); 2081 } 2082 } 2083 } 2084 } 2085 return (NULL); 2086 } 2087 2088 /** @ingroup Hash 2089 * @brief Find the SCTP association given the global port and vtag 2090 * 2091 * Searches the global look-up table for the association entry matching the 2092 * provided global <address:ports:vtag> tuple 2093 * 2094 * If all but the global address match it sets partial_match to 1 to indicate a 2095 * partial match. If the NAT is tracking global IP addresses for this 2096 * association, the NAT may respond with an ERRORM to request the missing 2097 * address to be added. 2098 * 2099 * @param la Pointer to the relevant libalias instance 2100 * @param g_addr global address 2101 * @param g_vtag global vtag 2102 * @param g_port global port 2103 * @param l_port local port 2104 * 2105 * @return pointer to association or NULL 2106 */ 2107 static struct sctp_nat_assoc * 2108 FindSctpGlobal(struct libalias *la, struct in_addr g_addr, uint32_t g_vtag, uint16_t g_port, uint16_t l_port, int *partial_match) 2109 { 2110 u_int i; 2111 struct sctp_nat_assoc *assoc = NULL; 2112 struct sctp_GlobalAddress *G_Addr = NULL; 2113 2114 *partial_match = 0; 2115 if (g_vtag != 0) { /* an init packet, vtag==0 */ 2116 i = SN_TABLE_HASH(g_vtag, g_port, la->sctpNatTableSize); 2117 LIST_FOREACH(assoc, &la->sctpTableGlobal[i], list_G) { 2118 if ((assoc->g_vtag == g_vtag) && (assoc->g_port == g_port) && (assoc->l_port == l_port)) { 2119 *partial_match = 1; 2120 if (assoc->num_Gaddr) { 2121 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) { 2122 if (G_Addr->g_addr.s_addr == g_addr.s_addr) 2123 return (assoc); 2124 } 2125 } else { 2126 return (assoc); 2127 } 2128 } 2129 } 2130 } 2131 return (NULL); 2132 } 2133 2134 /** @ingroup Hash 2135 * @brief Find the SCTP association for a T-Flag message (given the global port and local vtag) 2136 * 2137 * Searches the local look-up table for a unique association entry matching the 2138 * provided global port and local vtag information 2139 * 2140 * @param la Pointer to the relevant libalias instance 2141 * @param g_addr global address 2142 * @param l_vtag local Vtag 2143 * @param g_port global Port 2144 * @param l_port local Port 2145 * 2146 * @return pointer to association or NULL 2147 */ 2148 static struct sctp_nat_assoc * 2149 FindSctpLocalT(struct libalias *la, struct in_addr g_addr, uint32_t l_vtag, uint16_t g_port, uint16_t l_port) 2150 { 2151 u_int i; 2152 struct sctp_nat_assoc *assoc = NULL, *lastmatch = NULL; 2153 struct sctp_GlobalAddress *G_Addr = NULL; 2154 int cnt = 0; 2155 2156 if (l_vtag != 0) { /* an init packet, vtag==0 */ 2157 i = SN_TABLE_HASH(l_vtag, g_port, la->sctpNatTableSize); 2158 LIST_FOREACH(assoc, &la->sctpTableGlobal[i], list_G) { 2159 if ((assoc->g_vtag == l_vtag) && (assoc->g_port == g_port) && (assoc->l_port == l_port)) { 2160 if (assoc->num_Gaddr) { 2161 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) { 2162 if (G_Addr->g_addr.s_addr == g_addr.s_addr) 2163 return (assoc); /* full match */ 2164 } 2165 } else { 2166 if (++cnt > 1) 2167 return (NULL); 2168 lastmatch = assoc; 2169 } 2170 } 2171 } 2172 } 2173 /* If there is more than one match we do not know which local address to send to */ 2174 return (cnt ? lastmatch : NULL); 2175 } 2176 2177 /** @ingroup Hash 2178 * @brief Find the SCTP association for a T-Flag message (given the local port and global vtag) 2179 * 2180 * Searches the global look-up table for a unique association entry matching the 2181 * provided local port and global vtag information 2182 * 2183 * @param la Pointer to the relevant libalias instance 2184 * @param g_addr global address 2185 * @param g_vtag global vtag 2186 * @param l_port local port 2187 * @param g_port global port 2188 * 2189 * @return pointer to association or NULL 2190 */ 2191 static struct sctp_nat_assoc * 2192 FindSctpGlobalT(struct libalias *la, struct in_addr g_addr, uint32_t g_vtag, uint16_t l_port, uint16_t g_port) 2193 { 2194 u_int i; 2195 struct sctp_nat_assoc *assoc = NULL; 2196 struct sctp_GlobalAddress *G_Addr = NULL; 2197 2198 if (g_vtag != 0) { /* an init packet, vtag==0 */ 2199 i = SN_TABLE_HASH(g_vtag, l_port, la->sctpNatTableSize); 2200 LIST_FOREACH(assoc, &la->sctpTableLocal[i], list_L) { 2201 if ((assoc->l_vtag == g_vtag) && (assoc->l_port == l_port) && (assoc->g_port == g_port)) { 2202 if (assoc->num_Gaddr) { 2203 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) { 2204 if (G_Addr->g_addr.s_addr == g_addr.s_addr) 2205 return (assoc); 2206 } 2207 } else { 2208 return (assoc); 2209 } 2210 } 2211 } 2212 } 2213 return (NULL); 2214 } 2215 2216 /** @ingroup Hash 2217 * @brief Add the sctp association information to the local look up table 2218 * 2219 * Searches the local look-up table for an existing association with the same 2220 * details. If a match exists and is ONLY in the local look-up table then this 2221 * is a repeated INIT packet, we need to remove this association from the 2222 * look-up table and add the new association 2223 * 2224 * The new association is added to the head of the list and state is updated 2225 * 2226 * @param la Pointer to the relevant libalias instance 2227 * @param assoc pointer to sctp association 2228 * @param g_addr global address 2229 * 2230 * @return SN_ADD_OK | SN_ADD_CLASH 2231 */ 2232 static int 2233 AddSctpAssocLocal(struct libalias *la, struct sctp_nat_assoc *assoc, struct in_addr g_addr) 2234 { 2235 struct sctp_nat_assoc *found; 2236 2237 LIBALIAS_LOCK_ASSERT(la); 2238 found = FindSctpLocal(la, assoc->l_addr, g_addr, assoc->l_vtag, assoc->l_port, assoc->g_port); 2239 /* 2240 * Note that if a different global address initiated this Init, 2241 * ie it wasn't resent as presumed: 2242 * - the local receiver if receiving it for the first time will establish 2243 * an association with the new global host 2244 * - if receiving an init from a different global address after sending a 2245 * lost initack it will send an initack to the new global host, the first 2246 * association attempt will then be blocked if retried. 2247 */ 2248 if (found != NULL) { 2249 if ((found->TableRegister == SN_LOCAL_TBL) && (found->g_port == assoc->g_port)) { /* resent message */ 2250 RmSctpAssoc(la, found); 2251 sctp_RmTimeOut(la, found); 2252 freeGlobalAddressList(found); 2253 sn_free(found); 2254 } else 2255 return (SN_ADD_CLASH); 2256 } 2257 2258 LIST_INSERT_HEAD(&la->sctpTableLocal[SN_TABLE_HASH(assoc->l_vtag, assoc->l_port, la->sctpNatTableSize)], 2259 assoc, list_L); 2260 assoc->TableRegister |= SN_LOCAL_TBL; 2261 la->sctpLinkCount++; //increment link count 2262 2263 if (assoc->TableRegister == SN_BOTH_TBL) { 2264 /* libalias log -- controlled by libalias */ 2265 if (la->packetAliasMode & PKT_ALIAS_LOG) 2266 SctpShowAliasStats(la); 2267 2268 SN_LOG(SN_LOG_INFO, logsctpassoc(assoc, "^")); 2269 } 2270 2271 return (SN_ADD_OK); 2272 } 2273 2274 /** @ingroup Hash 2275 * @brief Add the sctp association information to the global look up table 2276 * 2277 * Searches the global look-up table for an existing association with the same 2278 * details. If a match exists and is ONLY in the global look-up table then this 2279 * is a repeated INIT packet, we need to remove this association from the 2280 * look-up table and add the new association 2281 * 2282 * The new association is added to the head of the list and state is updated 2283 * 2284 * @param la Pointer to the relevant libalias instance 2285 * @param assoc pointer to sctp association 2286 * 2287 * @return SN_ADD_OK | SN_ADD_CLASH 2288 */ 2289 static int 2290 AddSctpAssocGlobal(struct libalias *la, struct sctp_nat_assoc *assoc) 2291 { 2292 struct sctp_nat_assoc *found; 2293 2294 LIBALIAS_LOCK_ASSERT(la); 2295 found = FindSctpGlobalClash(la, assoc); 2296 if (found != NULL) { 2297 if ((found->TableRegister == SN_GLOBAL_TBL) && 2298 (found->l_addr.s_addr == assoc->l_addr.s_addr) && 2299 (found->l_port == assoc->l_port)) { /* resent message */ 2300 RmSctpAssoc(la, found); 2301 sctp_RmTimeOut(la, found); 2302 freeGlobalAddressList(found); 2303 sn_free(found); 2304 } else 2305 return (SN_ADD_CLASH); 2306 } 2307 2308 LIST_INSERT_HEAD(&la->sctpTableGlobal[SN_TABLE_HASH(assoc->g_vtag, assoc->g_port, la->sctpNatTableSize)], 2309 assoc, list_G); 2310 assoc->TableRegister |= SN_GLOBAL_TBL; 2311 la->sctpLinkCount++; //increment link count 2312 2313 if (assoc->TableRegister == SN_BOTH_TBL) { 2314 /* libalias log -- controlled by libalias */ 2315 if (la->packetAliasMode & PKT_ALIAS_LOG) 2316 SctpShowAliasStats(la); 2317 2318 SN_LOG(SN_LOG_INFO, logsctpassoc(assoc, "^")); 2319 } 2320 2321 return (SN_ADD_OK); 2322 } 2323 2324 /** @ingroup Hash 2325 * @brief Remove the sctp association information from the look up table 2326 * 2327 * For each of the two (local/global) look-up tables, remove the association 2328 * from that table IF it has been registered in that table. 2329 * 2330 * NOTE: The calling code is responsible for freeing memory allocated to the 2331 * association structure itself 2332 * 2333 * NOTE: The association is NOT removed from the timer queue 2334 * 2335 * @param la Pointer to the relevant libalias instance 2336 * @param assoc pointer to sctp association 2337 */ 2338 static void 2339 RmSctpAssoc(struct libalias *la, struct sctp_nat_assoc *assoc) 2340 { 2341 // struct sctp_nat_assoc *found; 2342 if (assoc == NULL) { 2343 /* very bad, log and die*/ 2344 SN_LOG(SN_LOG_LOW, 2345 logsctperror("ERROR: alias_sctp:RmSctpAssoc(NULL)\n", 0, 0, SN_TO_NODIR)); 2346 return; 2347 } 2348 /* log if association is fully up and now closing */ 2349 if (assoc->TableRegister == SN_BOTH_TBL) { 2350 SN_LOG(SN_LOG_INFO, logsctpassoc(assoc, "$")); 2351 } 2352 LIBALIAS_LOCK_ASSERT(la); 2353 if (assoc->TableRegister & SN_LOCAL_TBL) { 2354 assoc->TableRegister ^= SN_LOCAL_TBL; 2355 la->sctpLinkCount--; //decrement link count 2356 LIST_REMOVE(assoc, list_L); 2357 } 2358 2359 if (assoc->TableRegister & SN_GLOBAL_TBL) { 2360 assoc->TableRegister ^= SN_GLOBAL_TBL; 2361 la->sctpLinkCount--; //decrement link count 2362 LIST_REMOVE(assoc, list_G); 2363 } 2364 // sn_free(assoc); //Don't remove now, remove if needed later 2365 /* libalias logging -- controlled by libalias log definition */ 2366 if (la->packetAliasMode & PKT_ALIAS_LOG) 2367 SctpShowAliasStats(la); 2368 } 2369 2370 /** 2371 * @ingroup Hash 2372 * @brief free the Global Address List memory 2373 * 2374 * freeGlobalAddressList deletes all global IP addresses in an associations 2375 * global IP address list. 2376 * 2377 * @param assoc 2378 */ 2379 static void freeGlobalAddressList(struct sctp_nat_assoc *assoc) 2380 { 2381 struct sctp_GlobalAddress *gaddr1=NULL,*gaddr2=NULL; 2382 /*free global address list*/ 2383 gaddr1 = LIST_FIRST(&(assoc->Gaddr)); 2384 while (gaddr1 != NULL) { 2385 gaddr2 = LIST_NEXT(gaddr1, list_Gaddr); 2386 sn_free(gaddr1); 2387 gaddr1 = gaddr2; 2388 } 2389 } 2390 /* ---------------------------------------------------------------------- 2391 * TIMER QUEUE CODE 2392 * ---------------------------------------------------------------------- 2393 */ 2394 /** @addtogroup Timer 2395 * 2396 * The timer queue management functions are designed to operate efficiently with 2397 * a minimum of interaction with the queues. 2398 * 2399 * Once a timeout is set in the queue it will not be altered in the queue unless 2400 * it has to be changed to a shorter time (usually only for aborts and closing). 2401 * On a queue timeout, the real expiry time is checked, and if not leq than the 2402 * timeout it is requeued (O(1)) at its later time. This is especially important 2403 * for normal packets sent during an association. When a timer expires, it is 2404 * updated to its new expiration time if necessary, or processed as a 2405 * timeout. This means that while in UP state, the timing queue is only altered 2406 * every U_T (every few minutes) for a particular association. 2407 */ 2408 /** @ingroup Timer 2409 * @brief Add an association timeout to the timer queue 2410 * 2411 * Determine the location in the queue to add the timeout and insert the 2412 * association into the list at that queue position 2413 * 2414 * @param la 2415 * @param assoc 2416 */ 2417 static void 2418 sctp_AddTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc) 2419 { 2420 int add_loc; 2421 LIBALIAS_LOCK_ASSERT(la); 2422 add_loc = assoc->exp - la->sctpNatTimer.loc_time + la->sctpNatTimer.cur_loc; 2423 if (add_loc >= SN_TIMER_QUEUE_SIZE) 2424 add_loc -= SN_TIMER_QUEUE_SIZE; 2425 LIST_INSERT_HEAD(&la->sctpNatTimer.TimerQ[add_loc], assoc, timer_Q); 2426 assoc->exp_loc = add_loc; 2427 } 2428 2429 /** @ingroup Timer 2430 * @brief Remove an association from timer queue 2431 * 2432 * This is an O(1) operation to remove the association pointer from its 2433 * current position in the timer queue 2434 * 2435 * @param la Pointer to the relevant libalias instance 2436 * @param assoc pointer to sctp association 2437 */ 2438 static void 2439 sctp_RmTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc) 2440 { 2441 LIBALIAS_LOCK_ASSERT(la); 2442 LIST_REMOVE(assoc, timer_Q);/* Note this is O(1) */ 2443 } 2444 2445 /** @ingroup Timer 2446 * @brief Reset timer in timer queue 2447 * 2448 * Reset the actual timeout for the specified association. If it is earlier than 2449 * the existing timeout, then remove and re-install the association into the 2450 * queue 2451 * 2452 * @param la Pointer to the relevant libalias instance 2453 * @param assoc pointer to sctp association 2454 * @param newexp New expiration time 2455 */ 2456 static void 2457 sctp_ResetTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc, int newexp) 2458 { 2459 if (newexp < assoc->exp) { 2460 sctp_RmTimeOut(la, assoc); 2461 assoc->exp = newexp; 2462 sctp_AddTimeOut(la, assoc); 2463 } else { 2464 assoc->exp = newexp; 2465 } 2466 } 2467 2468 /** @ingroup Timer 2469 * @brief Check timer Q against current time 2470 * 2471 * Loop through each entry in the timer queue since the last time we processed 2472 * the timer queue until now (the current time). For each association in the 2473 * event list, we remove it from that position in the timer queue and check if 2474 * it has really expired. If so we: 2475 * - Log the timer expiry 2476 * - Remove the association from the NAT tables 2477 * - Release the memory used by the association 2478 * 2479 * If the timer hasn't really expired we place the association into its new 2480 * correct position in the timer queue. 2481 * 2482 * @param la Pointer to the relevant libalias instance 2483 */ 2484 void 2485 sctp_CheckTimers(struct libalias *la) 2486 { 2487 struct sctp_nat_assoc *assoc; 2488 2489 LIBALIAS_LOCK_ASSERT(la); 2490 while(LibAliasTime >= la->sctpNatTimer.loc_time) { 2491 while (!LIST_EMPTY(&la->sctpNatTimer.TimerQ[la->sctpNatTimer.cur_loc])) { 2492 assoc = LIST_FIRST(&la->sctpNatTimer.TimerQ[la->sctpNatTimer.cur_loc]); 2493 //SLIST_REMOVE_HEAD(&la->sctpNatTimer.TimerQ[la->sctpNatTimer.cur_loc], timer_Q); 2494 LIST_REMOVE(assoc, timer_Q); 2495 if (LibAliasTime >= assoc->exp) { /* state expired */ 2496 SN_LOG(((assoc->state == SN_CL) ? (SN_LOG_DEBUG) : (SN_LOG_INFO)), 2497 logsctperror("Timer Expired", assoc->g_vtag, assoc->state, SN_TO_NODIR)); 2498 RmSctpAssoc(la, assoc); 2499 freeGlobalAddressList(assoc); 2500 sn_free(assoc); 2501 } else {/* state not expired, reschedule timer*/ 2502 sctp_AddTimeOut(la, assoc); 2503 } 2504 } 2505 /* Goto next location in the timer queue*/ 2506 ++la->sctpNatTimer.loc_time; 2507 if (++la->sctpNatTimer.cur_loc >= SN_TIMER_QUEUE_SIZE) 2508 la->sctpNatTimer.cur_loc = 0; 2509 } 2510 } 2511 2512 /* ---------------------------------------------------------------------- 2513 * LOGGING CODE 2514 * ---------------------------------------------------------------------- 2515 */ 2516 /** @addtogroup Logging 2517 * 2518 * The logging functions provide logging of different items ranging from logging 2519 * a simple message, through logging an association details to logging the 2520 * current state of the NAT tables 2521 */ 2522 /** @ingroup Logging 2523 * @brief Log sctp nat errors 2524 * 2525 * @param errormsg Error message to be logged 2526 * @param vtag Current Vtag 2527 * @param error Error number 2528 * @param direction Direction of packet 2529 */ 2530 static void 2531 logsctperror(char *errormsg, uint32_t vtag, int error, int direction) 2532 { 2533 char dir; 2534 switch (direction) { 2535 case SN_TO_LOCAL: 2536 dir = 'L'; 2537 break; 2538 case SN_TO_GLOBAL: 2539 dir = 'G'; 2540 break; 2541 default: 2542 dir = '*'; 2543 break; 2544 } 2545 SctpAliasLog("->%c %s (vt=%u) %d\n", dir, errormsg, ntohl(vtag), error); 2546 } 2547 2548 /** @ingroup Logging 2549 * @brief Log what the parser parsed 2550 * 2551 * @param direction Direction of packet 2552 * @param sm Pointer to sctp message information 2553 */ 2554 static void 2555 logsctpparse(int direction, struct sctp_nat_msg *sm) 2556 { 2557 char *ploc, *pstate; 2558 switch (direction) { 2559 case SN_TO_LOCAL: 2560 ploc = "TO_LOCAL -"; 2561 break; 2562 case SN_TO_GLOBAL: 2563 ploc = "TO_GLOBAL -"; 2564 break; 2565 default: 2566 ploc = ""; 2567 } 2568 switch (sm->msg) { 2569 case SN_SCTP_INIT: 2570 pstate = "Init"; 2571 break; 2572 case SN_SCTP_INITACK: 2573 pstate = "InitAck"; 2574 break; 2575 case SN_SCTP_ABORT: 2576 pstate = "Abort"; 2577 break; 2578 case SN_SCTP_SHUTACK: 2579 pstate = "ShutAck"; 2580 break; 2581 case SN_SCTP_SHUTCOMP: 2582 pstate = "ShutComp"; 2583 break; 2584 case SN_SCTP_ASCONF: 2585 pstate = "Asconf"; 2586 break; 2587 case SN_SCTP_ASCONFACK: 2588 pstate = "AsconfAck"; 2589 break; 2590 case SN_SCTP_OTHER: 2591 pstate = "Other"; 2592 break; 2593 default: 2594 pstate = "***ERROR***"; 2595 break; 2596 } 2597 SctpAliasLog("Parsed: %s %s\n", ploc, pstate); 2598 } 2599 2600 /** @ingroup Logging 2601 * @brief Log an SCTP association's details 2602 * 2603 * @param assoc pointer to sctp association 2604 * @param s Character that indicates the state of processing for this packet 2605 */ 2606 static void logsctpassoc(struct sctp_nat_assoc *assoc, char *s) 2607 { 2608 struct sctp_GlobalAddress *G_Addr = NULL; 2609 char *sp; 2610 char addrbuf[INET_ADDRSTRLEN]; 2611 2612 switch (assoc->state) { 2613 case SN_ID: 2614 sp = "ID "; 2615 break; 2616 case SN_INi: 2617 sp = "INi "; 2618 break; 2619 case SN_INa: 2620 sp = "INa "; 2621 break; 2622 case SN_UP: 2623 sp = "UP "; 2624 break; 2625 case SN_CL: 2626 sp = "CL "; 2627 break; 2628 case SN_RM: 2629 sp = "RM "; 2630 break; 2631 default: 2632 sp = "***ERROR***"; 2633 break; 2634 } 2635 SctpAliasLog("%sAssoc: %s exp=%u la=%s lv=%u lp=%u gv=%u gp=%u tbl=%d\n", 2636 s, sp, assoc->exp, inet_ntoa_r(assoc->l_addr, addrbuf), 2637 ntohl(assoc->l_vtag), ntohs(assoc->l_port), 2638 ntohl(assoc->g_vtag), ntohs(assoc->g_port), 2639 assoc->TableRegister); 2640 /* list global addresses */ 2641 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) { 2642 SctpAliasLog("\t\tga=%s\n", 2643 inet_ntoa_r(G_Addr->g_addr, addrbuf)); 2644 } 2645 } 2646 2647 /** @ingroup Logging 2648 * @brief Output Global table to log 2649 * 2650 * @param la Pointer to the relevant libalias instance 2651 */ 2652 static void logSctpGlobal(struct libalias *la) 2653 { 2654 u_int i; 2655 struct sctp_nat_assoc *assoc = NULL; 2656 2657 SctpAliasLog("G->\n"); 2658 for (i = 0; i < la->sctpNatTableSize; i++) { 2659 LIST_FOREACH(assoc, &la->sctpTableGlobal[i], list_G) { 2660 logsctpassoc(assoc, " "); 2661 } 2662 } 2663 } 2664 2665 /** @ingroup Logging 2666 * @brief Output Local table to log 2667 * 2668 * @param la Pointer to the relevant libalias instance 2669 */ 2670 static void logSctpLocal(struct libalias *la) 2671 { 2672 u_int i; 2673 struct sctp_nat_assoc *assoc = NULL; 2674 2675 SctpAliasLog("L->\n"); 2676 for (i = 0; i < la->sctpNatTableSize; i++) { 2677 LIST_FOREACH(assoc, &la->sctpTableLocal[i], list_L) { 2678 logsctpassoc(assoc, " "); 2679 } 2680 } 2681 } 2682 2683 /** @ingroup Logging 2684 * @brief Output timer queue to log 2685 * 2686 * @param la Pointer to the relevant libalias instance 2687 */ 2688 static void logTimerQ(struct libalias *la) 2689 { 2690 static char buf[50]; 2691 u_int i; 2692 struct sctp_nat_assoc *assoc = NULL; 2693 2694 SctpAliasLog("t->\n"); 2695 for (i = 0; i < SN_TIMER_QUEUE_SIZE; i++) { 2696 LIST_FOREACH(assoc, &la->sctpNatTimer.TimerQ[i], timer_Q) { 2697 snprintf(buf, 50, " l=%u ",i); 2698 //SctpAliasLog(la->logDesc," l=%d ",i); 2699 logsctpassoc(assoc, buf); 2700 } 2701 } 2702 } 2703 2704 /** @ingroup Logging 2705 * @brief Sctp NAT logging function 2706 * 2707 * This function is based on a similar function in alias_db.c 2708 * 2709 * @param str/stream logging descriptor 2710 * @param format printf type string 2711 */ 2712 #ifdef _KERNEL 2713 static void 2714 SctpAliasLog(const char *format, ...) 2715 { 2716 char buffer[LIBALIAS_BUF_SIZE]; 2717 va_list ap; 2718 va_start(ap, format); 2719 vsnprintf(buffer, LIBALIAS_BUF_SIZE, format, ap); 2720 va_end(ap); 2721 log(LOG_SECURITY | LOG_INFO, "alias_sctp: %s", buffer); 2722 } 2723 #else 2724 static void 2725 SctpAliasLog(FILE *stream, const char *format, ...) 2726 { 2727 va_list ap; 2728 2729 va_start(ap, format); 2730 vfprintf(stream, format, ap); 2731 va_end(ap); 2732 fflush(stream); 2733 } 2734 #endif 2735