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