3 * Swinburne University of Technology, Melbourne, Australia.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS "AS IS" AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * Alias_sctp forms part of the libalias kernel module to handle
29 * Network Address Translation (NAT) for the SCTP protocol.
31 * This software was developed by David A. Hayes and Jason But
33 * The design is outlined in CAIA technical report number 080618A
34 * (D. Hayes and J. But, "Alias_sctp Version 0.1: SCTP NAT implementation in IPFW")
36 * Development is part of the CAIA SONATA project,
37 * proposed by Jason But and Grenville Armitage:
38 * http://caia.swin.edu.au/urp/sonata/
41 * This project has been made possible in part by a grant from
42 * the Cisco University Research Program Fund at Community
43 * Foundation Silicon Valley.
47 * Alias_sctp is part of the SONATA (http://caia.swin.edu.au/urp/sonata) project
48 * to develop and release a BSD licensed implementation of a Network Address
49 * Translation (NAT) module that supports the Stream Control Transmission
52 * Traditional address and port number look ups are inadequate for SCTP's
53 * operation due to both processing requirements and issues with multi-homing.
54 * Alias_sctp integrates with FreeBSD's ipfw/libalias NAT system.
56 * Version 0.2 features include:
57 * - Support for global multi-homing
58 * - Support for ASCONF modification from Internet Draft
59 * (draft-stewart-behave-sctpnat-04, R. Stewart and M. Tuexen, "Stream control
60 * transmission protocol (SCTP) network address translation," Jul. 2008) to
61 * provide support for multi-homed privately addressed hosts
62 * - Support for forwarding of T-flagged packets
63 * - Generation and delivery of AbortM/ErrorM packets upon detection of NAT
65 * - Per-port forwarding rules
66 * - Dynamically controllable logging and statistics
67 * - Dynamic management of timers
68 * - Dynamic control of hash-table size
74 #include <machine/stdarg.h>
75 #include <sys/param.h>
76 #include <sys/systm.h>
77 #include <sys/kernel.h>
78 #include <sys/module.h>
79 #include <sys/syslog.h>
80 #include <netinet/libalias/alias_sctp.h>
81 #include <netinet/libalias/alias.h>
82 #include <netinet/libalias/alias_local.h>
83 #include <netinet/sctp_crc32.h>
84 #include <machine/in_cksum.h>
86 #include "alias_sctp.h"
87 #include <arpa/inet.h>
89 #include "alias_local.h"
90 #include <machine/in_cksum.h>
91 #include <sys/libkern.h>
92 #endif //#ifdef _KERNEL
94 /* ----------------------------------------------------------------------
96 * ----------------------------------------------------------------------
98 /* Packet Parsing Functions */
99 static int sctp_PktParser(struct libalias *la, int direction, struct ip *pip,
100 struct sctp_nat_msg *sm, struct sctp_nat_assoc **passoc);
101 static int GetAsconfVtags(struct libalias *la, struct sctp_nat_msg *sm,
102 uint32_t *l_vtag, uint32_t *g_vtag, int direction);
103 static int IsASCONFack(struct libalias *la, struct sctp_nat_msg *sm, int direction);
105 static void AddGlobalIPAddresses(struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int direction);
106 static int Add_Global_Address_to_List(struct sctp_nat_assoc *assoc, struct sctp_GlobalAddress *G_addr);
107 static void RmGlobalIPAddresses(struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int direction);
108 static int IsADDorDEL(struct libalias *la, struct sctp_nat_msg *sm, int direction);
110 /* State Machine Functions */
111 static int ProcessSctpMsg(struct libalias *la, int direction, \
112 struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc);
114 static int ID_process(struct libalias *la, int direction,\
115 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm);
116 static int INi_process(struct libalias *la, int direction,\
117 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm);
118 static int INa_process(struct libalias *la, int direction,\
119 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm);
120 static int UP_process(struct libalias *la, int direction,\
121 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm);
122 static int CL_process(struct libalias *la, int direction,\
123 struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm);
124 static void TxAbortErrorM(struct libalias *la, struct sctp_nat_msg *sm,\
125 struct sctp_nat_assoc *assoc, int sndrply, int direction);
127 /* Hash Table Functions */
128 static struct sctp_nat_assoc*
129 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);
130 static struct sctp_nat_assoc*
131 FindSctpGlobal(struct libalias *la, struct in_addr g_addr, uint32_t g_vtag, uint16_t g_port, uint16_t l_port, int *partial_match);
132 static struct sctp_nat_assoc*
133 FindSctpGlobalClash(struct libalias *la, struct sctp_nat_assoc *Cassoc);
134 static struct sctp_nat_assoc*
135 FindSctpLocalT(struct libalias *la, struct in_addr g_addr, uint32_t l_vtag, uint16_t g_port, uint16_t l_port);
136 static struct sctp_nat_assoc*
137 FindSctpGlobalT(struct libalias *la, struct in_addr g_addr, uint32_t g_vtag, uint16_t l_port, uint16_t g_port);
139 static int AddSctpAssocLocal(struct libalias *la, struct sctp_nat_assoc *assoc, struct in_addr g_addr);
140 static int AddSctpAssocGlobal(struct libalias *la, struct sctp_nat_assoc *assoc);
141 static void RmSctpAssoc(struct libalias *la, struct sctp_nat_assoc *assoc);
142 static void freeGlobalAddressList(struct sctp_nat_assoc *assoc);
144 /* Timer Queue Functions */
145 static void sctp_AddTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc);
146 static void sctp_RmTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc);
147 static void sctp_ResetTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc, int newexp);
148 void sctp_CheckTimers(struct libalias *la);
151 /* Logging Functions */
152 static void logsctperror(char* errormsg, uint32_t vtag, int error, int direction);
153 static void logsctpparse(int direction, struct sctp_nat_msg *sm);
154 static void logsctpassoc(struct sctp_nat_assoc *assoc, char *s);
155 static void logTimerQ(struct libalias *la);
156 static void logSctpGlobal(struct libalias *la);
157 static void logSctpLocal(struct libalias *la);
159 static void SctpAliasLog(const char *format, ...);
162 /** @defgroup external External code changes and modifications
164 * Some changes have been made to files external to alias_sctp.(c|h). These
165 * changes are primarily due to code needing to call static functions within
166 * those files or to perform extra functionality that can only be performed
167 * within these files.
169 /** @ingroup external
170 * @brief Log current statistics for the libalias instance
172 * This function is defined in alias_db.c, since it calls static functions in
175 * Calls the higher level ShowAliasStats() in alias_db.c which logs all current
176 * statistics about the libalias instance - including SCTP statistics
178 * @param la Pointer to the libalias instance
180 void SctpShowAliasStats(struct libalias *la);
184 static MALLOC_DEFINE(M_SCTPNAT, "sctpnat", "sctp nat dbs");
185 /* Use kernel allocator. */
186 #ifdef _SYS_MALLOC_H_
187 #define sn_malloc(x) malloc(x, M_SCTPNAT, M_NOWAIT|M_ZERO)
188 #define sn_calloc(n,x) sn_malloc(x * n)
189 #define sn_free(x) free(x, M_SCTPNAT)
190 #endif// #ifdef _SYS_MALLOC_H_
192 #else //#ifdef _KERNEL
193 #define sn_malloc(x) malloc(x)
194 #define sn_calloc(n, x) calloc(n, x)
195 #define sn_free(x) free(x)
197 #endif //#ifdef _KERNEL
199 /** @defgroup packet_parser SCTP Packet Parsing
202 * - Return pointers to the first and next SCTP chunks within an SCTP Packet
203 * - Define possible return values of the packet parsing process
204 * - SCTP message types for storing in the sctp_nat_msg structure @{
207 #define SN_SCTP_FIRSTCHUNK(sctphead) (struct sctp_chunkhdr *)(((char *)sctphead) + sizeof(struct sctphdr))
208 /**< Returns a pointer to the first chunk in an SCTP packet given a pointer to the SCTP header */
210 #define SN_SCTP_NEXTCHUNK(chunkhead) (struct sctp_chunkhdr *)(((char *)chunkhead) + SCTP_SIZE32(ntohs(chunkhead->chunk_length)))
211 /**< Returns a pointer to the next chunk in an SCTP packet given a pointer to the current chunk */
213 #define SN_SCTP_NEXTPARAM(param) (struct sctp_paramhdr *)(((char *)param) + SCTP_SIZE32(ntohs(param->param_length)))
214 /**< Returns a pointer to the next parameter in an SCTP packet given a pointer to the current parameter */
216 #define SN_MIN_CHUNK_SIZE 4 /**< Smallest possible SCTP chunk size in bytes */
217 #define SN_MIN_PARAM_SIZE 4 /**< Smallest possible SCTP param size in bytes */
218 #define SN_VTAG_PARAM_SIZE 12 /**< Size of SCTP ASCONF vtag param in bytes */
219 #define SN_ASCONFACK_PARAM_SIZE 8 /**< Size of SCTP ASCONF ACK param in bytes */
221 /* Packet parsing return codes */
222 #define SN_PARSE_OK 0 /**< Packet parsed for SCTP messages */
223 #define SN_PARSE_ERROR_IPSHL 1 /**< Packet parsing error - IP and SCTP common header len */
224 #define SN_PARSE_ERROR_AS_MALLOC 2 /**< Packet parsing error - assoc malloc */
225 #define SN_PARSE_ERROR_CHHL 3 /**< Packet parsing error - Chunk header len */
226 #define SN_PARSE_ERROR_DIR 4 /**< Packet parsing error - Direction */
227 #define SN_PARSE_ERROR_VTAG 5 /**< Packet parsing error - Vtag */
228 #define SN_PARSE_ERROR_CHUNK 6 /**< Packet parsing error - Chunk */
229 #define SN_PARSE_ERROR_PORT 7 /**< Packet parsing error - Port=0 */
230 #define SN_PARSE_ERROR_LOOKUP 8 /**< Packet parsing error - Lookup */
231 #define SN_PARSE_ERROR_PARTIALLOOKUP 9 /**< Packet parsing error - partial lookup only found */
232 #define SN_PARSE_ERROR_LOOKUP_ABORT 10 /**< Packet parsing error - Lookup - but abort packet */
234 /* Alias_sctp performs its processing based on a number of key messages */
235 #define SN_SCTP_ABORT 0x0000 /**< a packet containing an ABORT chunk */
236 #define SN_SCTP_INIT 0x0001 /**< a packet containing an INIT chunk */
237 #define SN_SCTP_INITACK 0x0002 /**< a packet containing an INIT-ACK chunk */
238 #define SN_SCTP_SHUTCOMP 0x0010 /**< a packet containing a SHUTDOWN-COMPLETE chunk */
239 #define SN_SCTP_SHUTACK 0x0020 /**< a packet containing a SHUTDOWN-ACK chunk */
240 #define SN_SCTP_ASCONF 0x0100 /**< a packet containing an ASCONF chunk */
241 #define SN_SCTP_ASCONFACK 0x0200 /**< a packet containing an ASCONF-ACK chunk */
242 #define SN_SCTP_OTHER 0xFFFF /**< a packet containing a chunk that is not of interest */
245 * @defgroup state_machine SCTP NAT State Machine
247 * Defines the various states an association can be within the NAT @{
249 #define SN_ID 0x0000 /**< Idle state */
250 #define SN_INi 0x0010 /**< Initialising, waiting for InitAck state */
251 #define SN_INa 0x0020 /**< Initialising, waiting for AddIpAck state */
252 #define SN_UP 0x0100 /**< Association in UP state */
253 #define SN_CL 0x1000 /**< Closing state */
254 #define SN_RM 0x2000 /**< Removing state */
257 * @defgroup Logging Logging Functionality
259 * Define various log levels and a macro to call specified log functions only if
260 * the current log level (sysctl_log_level) matches the specified level @{
263 #define SN_LOG_EVENT 1
264 #define SN_LOG_INFO 2
265 #define SN_LOG_DETAIL 3
266 #define SN_LOG_DEBUG 4
267 #define SN_LOG_DEBUG_MAX 5
269 #define SN_LOG(level, action) if (sysctl_log_level >= level) { action; } /**< Perform log action ONLY if the current log level meets the specified log level */
272 * @defgroup Hash Hash Table Macros and Functions
274 * Defines minimum/maximum/default values for the hash table size @{
276 #define SN_MIN_HASH_SIZE 101 /**< Minimum hash table size (set to stop users choosing stupid values) */
277 #define SN_MAX_HASH_SIZE 1000001 /**< Maximum hash table size (NB must be less than max int) */
278 #define SN_DEFAULT_HASH_SIZE 2003 /**< A reasonable default size for the hash tables */
280 #define SN_LOCAL_TBL 0x01 /**< assoc in local table */
281 #define SN_GLOBAL_TBL 0x02 /**< assoc in global table */
282 #define SN_BOTH_TBL 0x03 /**< assoc in both tables */
283 #define SN_WAIT_TOLOCAL 0x10 /**< assoc waiting for TOLOCAL asconf ACK*/
284 #define SN_WAIT_TOGLOBAL 0x20 /**< assoc waiting for TOLOCAL asconf ACK*/
285 #define SN_NULL_TBL 0x00 /**< assoc in No table */
286 #define SN_MAX_GLOBAL_ADDRESSES 100 /**< absolute maximum global address count*/
288 #define SN_ADD_OK 0 /**< Association added to the table */
289 #define SN_ADD_CLASH 1 /**< Clash when trying to add the assoc. info to the table */
291 #define SN_TABLE_HASH(vtag, port, size) (((u_int) vtag + (u_int) port) % (u_int) size) /**< Calculate the hash table lookup position */
294 * @defgroup Timer Timer Queue Macros and Functions
296 * Timer macros set minimum/maximum timeout values and calculate timer expiry
297 * times for the provided libalias instance @{
299 #define SN_MIN_TIMER 1
300 #define SN_MAX_TIMER 600
301 #define SN_TIMER_QUEUE_SIZE SN_MAX_TIMER+2
303 #define SN_I_T(la) (la->timeStamp + sysctl_init_timer) /**< INIT State expiration time in seconds */
304 #define SN_U_T(la) (la->timeStamp + sysctl_up_timer) /**< UP State expiration time in seconds */
305 #define SN_C_T(la) (la->timeStamp + sysctl_shutdown_timer) /**< CL State expiration time in seconds */
306 #define SN_X_T(la) (la->timeStamp + sysctl_holddown_timer) /**< Wait after a shutdown complete in seconds */
309 * @defgroup sysctl SysCtl Variable and callback function declarations
311 * Sysctl variables to modify NAT functionality in real-time along with associated functions
312 * to manage modifications to the sysctl variables @{
316 int sysctl_chg_loglevel(SYSCTL_HANDLER_ARGS);
317 int sysctl_chg_timer(SYSCTL_HANDLER_ARGS);
318 int sysctl_chg_hashtable_size(SYSCTL_HANDLER_ARGS);
319 int sysctl_chg_error_on_ootb(SYSCTL_HANDLER_ARGS);
320 int sysctl_chg_accept_global_ootb_addip(SYSCTL_HANDLER_ARGS);
321 int sysctl_chg_initialising_chunk_proc_limit(SYSCTL_HANDLER_ARGS);
322 int sysctl_chg_chunk_proc_limit(SYSCTL_HANDLER_ARGS);
323 int sysctl_chg_param_proc_limit(SYSCTL_HANDLER_ARGS);
324 int sysctl_chg_track_global_addresses(SYSCTL_HANDLER_ARGS);
326 /* Sysctl variables */
327 /** @brief net.inet.ip.alias.sctp.log_level */
328 static u_int sysctl_log_level = 0; /**< Stores the current level of logging */
329 /** @brief net.inet.ip.alias.sctp.init_timer */
330 static u_int sysctl_init_timer = 15; /**< Seconds to hold an association in the table waiting for an INIT-ACK or AddIP-ACK */
331 /** @brief net.inet.ip.alias.sctp.up_timer */
332 static u_int sysctl_up_timer = 300; /**< Seconds to hold an association in the table while no packets are transmitted */
333 /** @brief net.inet.ip.alias.sctp.shutdown_timer */
334 static u_int sysctl_shutdown_timer = 15; /**< Seconds to hold an association in the table waiting for a SHUTDOWN-COMPLETE */
335 /** @brief net.inet.ip.alias.sctp.holddown_timer */
336 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) */
337 /** @brief net.inet.ip.alias.sctp.hashtable_size */
338 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 */
339 /** @brief net.inet.ip.alias.sctp.error_on_ootb */
340 static u_int sysctl_error_on_ootb = 1; /**< NAT response to receipt of OOTB packet
341 (0 - No response, 1 - NAT will send ErrorM only to local side,
342 2 - NAT will send local ErrorM and global ErrorM if there was a partial association match
343 3 - NAT will send ErrorM to both local and global) */
344 /** @brief net.inet.ip.alias.sctp.accept_global_ootb_addip */
345 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)) */
346 /** @brief net.inet.ip.alias.sctp.initialising_chunk_proc_limit */
347 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) */
348 /** @brief net.inet.ip.alias.sctp.param_proc_limit */
349 static u_int sysctl_chunk_proc_limit = 5; /**< A limit on the number of chunks that should be searched (DoS prevention) */
350 /** @brief net.inet.ip.alias.sctp.param_proc_limit */
351 static u_int sysctl_param_proc_limit = 25; /**< A limit on the number of parameters (in chunks) that should be searched (DoS prevention) */
352 /** @brief net.inet.ip.alias.sctp.track_global_addresses */
353 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)
354 If set to >=1 the NAT will track that many global IP addresses. This may reduce look up table conflicts, but increases processing */
356 #define SN_NO_ERROR_ON_OOTB 0 /**< Send no errorM on out of the blue packets */
357 #define SN_LOCAL_ERROR_ON_OOTB 1 /**< Send only local errorM on out of the blue packets */
358 #define SN_LOCALandPARTIAL_ERROR_ON_OOTB 2 /**< Send local errorM and global errorM for out of the blue packets only if partial match found */
359 #define SN_ERROR_ON_OOTB 3 /**< Send errorM on out of the blue packets */
363 SYSCTL_DECL(_net_inet);
364 SYSCTL_DECL(_net_inet_ip);
365 SYSCTL_DECL(_net_inet_ip_alias);
367 static SYSCTL_NODE(_net_inet_ip_alias, OID_AUTO, sctp, CTLFLAG_RW, NULL,
369 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, log_level, CTLTYPE_UINT | CTLFLAG_RW,
370 &sysctl_log_level, 0, sysctl_chg_loglevel, "IU",
371 "Level of detail (0 - default, 1 - event, 2 - info, 3 - detail, 4 - debug, 5 - max debug)");
372 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, init_timer, CTLTYPE_UINT | CTLFLAG_RW,
373 &sysctl_init_timer, 0, sysctl_chg_timer, "IU",
374 "Timeout value (s) while waiting for (INIT-ACK|AddIP-ACK)");
375 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, up_timer, CTLTYPE_UINT | CTLFLAG_RW,
376 &sysctl_up_timer, 0, sysctl_chg_timer, "IU",
377 "Timeout value (s) to keep an association up with no traffic");
378 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, shutdown_timer, CTLTYPE_UINT | CTLFLAG_RW,
379 &sysctl_shutdown_timer, 0, sysctl_chg_timer, "IU",
380 "Timeout value (s) while waiting for SHUTDOWN-COMPLETE");
381 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, holddown_timer, CTLTYPE_UINT | CTLFLAG_RW,
382 &sysctl_holddown_timer, 0, sysctl_chg_timer, "IU",
383 "Hold association in table for this many seconds after receiving a SHUTDOWN-COMPLETE");
384 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, hashtable_size, CTLTYPE_UINT | CTLFLAG_RW,
385 &sysctl_hashtable_size, 0, sysctl_chg_hashtable_size, "IU",
386 "Size of hash tables used for NAT lookups (100 < prime_number > 1000001)");
387 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, error_on_ootb, CTLTYPE_UINT | CTLFLAG_RW,
388 &sysctl_error_on_ootb, 0, sysctl_chg_error_on_ootb, "IU",
389 "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)");
390 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, accept_global_ootb_addip, CTLTYPE_UINT | CTLFLAG_RW,
391 &sysctl_accept_global_ootb_addip, 0, sysctl_chg_accept_global_ootb_addip, "IU",
392 "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)");
393 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, initialising_chunk_proc_limit, CTLTYPE_UINT | CTLFLAG_RW,
394 &sysctl_initialising_chunk_proc_limit, 0, sysctl_chg_initialising_chunk_proc_limit, "IU",
395 "Number of chunks that should be processed if there is no current association found:\n\t > 0 (A high value is a DoS risk)");
396 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, chunk_proc_limit, CTLTYPE_UINT | CTLFLAG_RW,
397 &sysctl_chunk_proc_limit, 0, sysctl_chg_chunk_proc_limit, "IU",
398 "Number of chunks that should be processed to find key chunk:\n\t>= initialising_chunk_proc_limit (A high value is a DoS risk)");
399 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, param_proc_limit, CTLTYPE_UINT | CTLFLAG_RW,
400 &sysctl_param_proc_limit, 0, sysctl_chg_param_proc_limit, "IU",
401 "Number of parameters (in a chunk) that should be processed to find key parameters:\n\t> 1 (A high value is a DoS risk)");
402 SYSCTL_PROC(_net_inet_ip_alias_sctp, OID_AUTO, track_global_addresses, CTLTYPE_UINT | CTLFLAG_RW,
403 &sysctl_track_global_addresses, 0, sysctl_chg_track_global_addresses, "IU",
404 "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");
406 #endif /* SYSCTL_NODE */
410 * @brief sysctl callback for changing net.inet.ip.fw.sctp.log_level
412 * Updates the variable sysctl_log_level to the provided value and ensures
413 * it is in the valid range (SN_LOG_LOW -> SN_LOG_DEBUG)
415 int sysctl_chg_loglevel(SYSCTL_HANDLER_ARGS)
417 u_int level = *(u_int *)arg1;
420 error = sysctl_handle_int(oidp, &level, 0, req);
421 if (error) return (error);
423 sysctl_log_level = (level > SN_LOG_DEBUG_MAX)?(SN_LOG_DEBUG_MAX):(level);
424 sysctl_log_level = (level < SN_LOG_LOW)?(SN_LOG_LOW):(level);
430 * @brief sysctl callback for changing net.inet.ip.fw.sctp.(init_timer|up_timer|shutdown_timer)
432 * Updates the timer-based sysctl variables. The new values are sanity-checked
433 * to make sure that they are within the range SN_MIN_TIMER-SN_MAX_TIMER. The
434 * holddown timer is allowed to be 0
436 int sysctl_chg_timer(SYSCTL_HANDLER_ARGS)
438 u_int timer = *(u_int *)arg1;
441 error = sysctl_handle_int(oidp, &timer, 0, req);
442 if (error) return (error);
444 timer = (timer > SN_MAX_TIMER)?(SN_MAX_TIMER):(timer);
446 if (((u_int *)arg1) != &sysctl_holddown_timer)
448 timer = (timer < SN_MIN_TIMER)?(SN_MIN_TIMER):(timer);
451 *(u_int *)arg1 = timer;
457 * @brief sysctl callback for changing net.inet.ip.alias.sctp.hashtable_size
459 * Updates the hashtable_size sysctl variable. The new value should be a prime
460 * number. We sanity check to ensure that the size is within the range
461 * SN_MIN_HASH_SIZE-SN_MAX_HASH_SIZE. We then check the provided number to see
462 * if it is prime. We approximate by checking that (2,3,5,7,11) are not factors,
463 * incrementing the user provided value until we find a suitable number.
465 int sysctl_chg_hashtable_size(SYSCTL_HANDLER_ARGS)
467 u_int size = *(u_int *)arg1;
470 error = sysctl_handle_int(oidp, &size, 0, req);
471 if (error) return (error);
473 size = (size < SN_MIN_HASH_SIZE)?(SN_MIN_HASH_SIZE):((size > SN_MAX_HASH_SIZE)?(SN_MAX_HASH_SIZE):(size));
475 size |= 0x00000001; /* make odd */
477 for(;(((size % 3) == 0) || ((size % 5) == 0) || ((size % 7) == 0) || ((size % 11) == 0)); size+=2);
478 sysctl_hashtable_size = size;
484 * @brief sysctl callback for changing net.inet.ip.alias.sctp.error_on_ootb
486 * Updates the error_on_clash sysctl variable.
487 * If set to 0, no ErrorM will be sent if there is a look up table clash
488 * If set to 1, an ErrorM is sent only to the local side
489 * If set to 2, an ErrorM is sent to the local side and global side if there is
490 * a partial association match
491 * If set to 3, an ErrorM is sent to both local and global sides (DoS) risk.
493 int sysctl_chg_error_on_ootb(SYSCTL_HANDLER_ARGS)
495 u_int flag = *(u_int *)arg1;
498 error = sysctl_handle_int(oidp, &flag, 0, req);
499 if (error) return (error);
501 sysctl_error_on_ootb = (flag > SN_ERROR_ON_OOTB) ? SN_ERROR_ON_OOTB: flag;
507 * @brief sysctl callback for changing net.inet.ip.alias.sctp.accept_global_ootb_addip
509 * If set to 1 the NAT will accept ootb global addip messages for processing (Security risk)
510 * Default is 0, only responding to local ootb AddIP messages
512 int sysctl_chg_accept_global_ootb_addip(SYSCTL_HANDLER_ARGS)
514 u_int flag = *(u_int *)arg1;
517 error = sysctl_handle_int(oidp, &flag, 0, req);
518 if (error) return (error);
520 sysctl_accept_global_ootb_addip = (flag == 1) ? 1: 0;
526 * @brief sysctl callback for changing net.inet.ip.alias.sctp.initialising_chunk_proc_limit
528 * Updates the initialising_chunk_proc_limit sysctl variable. Number of chunks
529 * that should be processed if there is no current association found: > 0 (A
530 * high value is a DoS risk)
532 int sysctl_chg_initialising_chunk_proc_limit(SYSCTL_HANDLER_ARGS)
534 u_int proclimit = *(u_int *)arg1;
537 error = sysctl_handle_int(oidp, &proclimit, 0, req);
538 if (error) return (error);
540 sysctl_initialising_chunk_proc_limit = (proclimit < 1) ? 1: proclimit;
541 sysctl_chunk_proc_limit =
542 (sysctl_chunk_proc_limit < sysctl_initialising_chunk_proc_limit) ? sysctl_initialising_chunk_proc_limit : sysctl_chunk_proc_limit;
548 * @brief sysctl callback for changing net.inet.ip.alias.sctp.chunk_proc_limit
550 * Updates the chunk_proc_limit sysctl variable.
551 * Number of chunks that should be processed to find key chunk:
552 * >= initialising_chunk_proc_limit (A high value is a DoS risk)
554 int sysctl_chg_chunk_proc_limit(SYSCTL_HANDLER_ARGS)
556 u_int proclimit = *(u_int *)arg1;
559 error = sysctl_handle_int(oidp, &proclimit, 0, req);
560 if (error) return (error);
562 sysctl_chunk_proc_limit =
563 (proclimit < sysctl_initialising_chunk_proc_limit) ? sysctl_initialising_chunk_proc_limit : proclimit;
570 * @brief sysctl callback for changing net.inet.ip.alias.sctp.param_proc_limit
572 * Updates the param_proc_limit sysctl variable.
573 * Number of parameters that should be processed to find key parameters:
574 * > 1 (A high value is a DoS risk)
576 int sysctl_chg_param_proc_limit(SYSCTL_HANDLER_ARGS)
578 u_int proclimit = *(u_int *)arg1;
581 error = sysctl_handle_int(oidp, &proclimit, 0, req);
582 if (error) return (error);
584 sysctl_param_proc_limit =
585 (proclimit < 2) ? 2 : proclimit;
591 * @brief sysctl callback for changing net.inet.ip.alias.sctp.track_global_addresses
593 *Configures the global address tracking option within the NAT (0 - Global
594 *tracking is disabled, > 0 - enables tracking but limits the number of global
595 *IP addresses to this value)
597 int sysctl_chg_track_global_addresses(SYSCTL_HANDLER_ARGS)
599 u_int num_to_track = *(u_int *)arg1;
602 error = sysctl_handle_int(oidp, &num_to_track, 0, req);
603 if (error) return (error);
605 sysctl_track_global_addresses = (num_to_track > SN_MAX_GLOBAL_ADDRESSES) ? SN_MAX_GLOBAL_ADDRESSES : num_to_track;
611 /* ----------------------------------------------------------------------
613 * ----------------------------------------------------------------------
616 * @brief Initialises the SCTP NAT Implementation
618 * Creates the look-up tables and the timer queue and initialises all state
621 * @param la Pointer to the relevant libalias instance
623 void AliasSctpInit(struct libalias *la)
625 /* Initialise association tables*/
627 la->sctpNatTableSize = sysctl_hashtable_size;
629 SctpAliasLog("Initialising SCTP NAT Instance (hash_table_size:%d)\n", la->sctpNatTableSize));
630 la->sctpTableLocal = sn_calloc(la->sctpNatTableSize, sizeof(struct sctpNatTableL));
631 la->sctpTableGlobal = sn_calloc(la->sctpNatTableSize, sizeof(struct sctpNatTableG));
632 la->sctpNatTimer.TimerQ = sn_calloc(SN_TIMER_QUEUE_SIZE, sizeof(struct sctpTimerQ));
633 /* Initialise hash table */
634 for (i = 0; i < la->sctpNatTableSize; i++) {
635 LIST_INIT(&la->sctpTableLocal[i]);
636 LIST_INIT(&la->sctpTableGlobal[i]);
639 /* Initialise circular timer Q*/
640 for (i = 0; i < SN_TIMER_QUEUE_SIZE; i++)
641 LIST_INIT(&la->sctpNatTimer.TimerQ[i]);
643 la->sctpNatTimer.loc_time=time_uptime; /* la->timeStamp is not set yet */
645 la->sctpNatTimer.loc_time=la->timeStamp;
647 la->sctpNatTimer.cur_loc = 0;
648 la->sctpLinkCount = 0;
652 * @brief Cleans-up the SCTP NAT Implementation prior to unloading
654 * Removes all entries from the timer queue, freeing associations as it goes.
655 * We then free memory allocated to the look-up tables and the time queue
657 * NOTE: We do not need to traverse the look-up tables as each association
658 * will always have an entry in the timer queue, freeing this memory
659 * once will free all memory allocated to entries in the look-up tables
661 * @param la Pointer to the relevant libalias instance
663 void AliasSctpTerm(struct libalias *la)
665 struct sctp_nat_assoc *assoc1, *assoc2;
668 LIBALIAS_LOCK_ASSERT(la);
670 SctpAliasLog("Removing SCTP NAT Instance\n"));
671 for (i = 0; i < SN_TIMER_QUEUE_SIZE; i++) {
672 assoc1 = LIST_FIRST(&la->sctpNatTimer.TimerQ[i]);
673 while (assoc1 != NULL) {
674 freeGlobalAddressList(assoc1);
675 assoc2 = LIST_NEXT(assoc1, timer_Q);
681 sn_free(la->sctpTableLocal);
682 sn_free(la->sctpTableGlobal);
683 sn_free(la->sctpNatTimer.TimerQ);
687 * @brief Handles SCTP packets passed from libalias
689 * This function needs to actually NAT/drop packets and possibly create and
690 * send AbortM or ErrorM packets in response. The process involves:
691 * - Validating the direction parameter passed by the caller
692 * - Checking and handling any expired timers for the NAT
693 * - Calling sctp_PktParser() to parse the packet
694 * - Call ProcessSctpMsg() to decide the appropriate outcome and to update
696 * - Based on the return code either:
698 * - Construct and send an ErrorM|AbortM packet
699 * - Mark the association for removal from the tables
700 * - Potentially remove the association from all lookup tables
701 * - Return the appropriate result to libalias
703 * @param la Pointer to the relevant libalias instance
704 * @param pip Pointer to IP packet to process
705 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
707 * @return PKT_ALIAS_OK | PKT_ALIAS_IGNORE | PKT_ALIAS_ERROR
710 SctpAlias(struct libalias *la, struct ip *pip, int direction)
713 struct sctp_nat_msg msg;
714 struct sctp_nat_assoc *assoc = NULL;
716 if ((direction != SN_TO_LOCAL) && (direction != SN_TO_GLOBAL)) {
717 SctpAliasLog("ERROR: Invalid direction\n");
718 return(PKT_ALIAS_ERROR);
721 sctp_CheckTimers(la); /* Check timers */
723 /* Parse the packet */
724 rtnval = sctp_PktParser(la, direction, pip, &msg, &assoc); //using *char (change to mbuf when get code from paolo)
728 case SN_PARSE_ERROR_CHHL:
729 /* Not an error if there is a chunk length parsing error and this is a fragmented packet */
730 if (ntohs(pip->ip_off) & IP_MF) {
731 rtnval = SN_PARSE_OK;
735 logsctperror("SN_PARSE_ERROR", msg.sctp_hdr->v_tag, rtnval, direction));
736 return(PKT_ALIAS_ERROR);
737 case SN_PARSE_ERROR_PARTIALLOOKUP:
738 if (sysctl_error_on_ootb > SN_LOCALandPARTIAL_ERROR_ON_OOTB) {
740 logsctperror("SN_PARSE_ERROR", msg.sctp_hdr->v_tag, rtnval, direction));
741 return(PKT_ALIAS_ERROR);
743 case SN_PARSE_ERROR_LOOKUP:
744 if (sysctl_error_on_ootb == SN_ERROR_ON_OOTB ||
745 (sysctl_error_on_ootb == SN_LOCALandPARTIAL_ERROR_ON_OOTB && direction == SN_TO_LOCAL) ||
746 (sysctl_error_on_ootb == SN_LOCAL_ERROR_ON_OOTB && direction == SN_TO_GLOBAL)) {
747 TxAbortErrorM(la, &msg, assoc, SN_REFLECT_ERROR, direction); /*NB assoc=NULL */
748 return(PKT_ALIAS_RESPOND);
752 logsctperror("SN_PARSE_ERROR", msg.sctp_hdr->v_tag, rtnval, direction));
753 return(PKT_ALIAS_ERROR);
756 SN_LOG(SN_LOG_DETAIL,
757 logsctpassoc(assoc, "*");
758 logsctpparse(direction, &msg);
761 /* Process the SCTP message */
762 rtnval = ProcessSctpMsg(la, direction, &msg, assoc);
764 SN_LOG(SN_LOG_DEBUG_MAX,
765 logsctpassoc(assoc, "-");
769 SN_LOG(SN_LOG_DEBUG, logTimerQ(la));
775 DifferentialChecksum(&(msg.ip_hdr->ip_sum),
776 &(assoc->l_addr), &(msg.ip_hdr->ip_dst), 2);
777 msg.ip_hdr->ip_dst = assoc->l_addr; /* change dst address to local address*/
780 DifferentialChecksum(&(msg.ip_hdr->ip_sum),
781 &(assoc->a_addr), &(msg.ip_hdr->ip_src), 2);
782 msg.ip_hdr->ip_src = assoc->a_addr; /* change src to alias addr*/
785 rtnval = SN_DROP_PKT; /* shouldn't get here, but if it does drop packet */
786 SN_LOG(SN_LOG_LOW, logsctperror("ERROR: Invalid direction", msg.sctp_hdr->v_tag, rtnval, direction));
791 SN_LOG(SN_LOG_DETAIL, logsctperror("SN_DROP_PKT", msg.sctp_hdr->v_tag, rtnval, direction));
796 TxAbortErrorM(la, &msg, assoc, rtnval, direction);
799 // big error, remove association and go to idle and write log messages
800 SN_LOG(SN_LOG_LOW, logsctperror("SN_PROCESSING_ERROR", msg.sctp_hdr->v_tag, rtnval, direction));
801 assoc->state=SN_RM;/* Mark for removal*/
805 /* Remove association if tagged for removal */
806 if (assoc->state == SN_RM) {
807 if (assoc->TableRegister) {
808 sctp_RmTimeOut(la, assoc);
809 RmSctpAssoc(la, assoc);
811 LIBALIAS_LOCK_ASSERT(la);
812 freeGlobalAddressList(assoc);
817 return(PKT_ALIAS_OK);
819 return(PKT_ALIAS_OK);
822 case SN_REFLECT_ERROR:
823 return(PKT_ALIAS_RESPOND);
826 return(PKT_ALIAS_ERROR);
831 * @brief Send an AbortM or ErrorM
833 * We construct the new SCTP packet to send in place of the existing packet we
834 * have been asked to NAT. This function can only be called if the original
835 * packet was successfully parsed as a valid SCTP packet.
837 * An AbortM (without cause) packet is the smallest SCTP packet available and as
838 * such there is always space in the existing packet buffer to fit the AbortM
839 * packet. An ErrorM packet is 4 bytes longer than the (the error cause is not
840 * optional). An ErrorM is sent in response to an AddIP when the Vtag/address
841 * combination, if added, will produce a conflict in the association look up
842 * tables. It may also be used for an unexpected packet - a packet with no
843 * matching association in the NAT table and we are requesting an AddIP so we
844 * can add it. The smallest valid SCTP packet while the association is in an
845 * up-state is a Heartbeat packet, which is big enough to be transformed to an
848 * We create a temporary character array to store the packet as we are constructing
849 * it. We then populate the array with appropriate values based on:
850 * - Packet type (AbortM | ErrorM)
851 * - Initial packet direction (SN_TO_LOCAL | SN_TO_GLOBAL)
852 * - NAT response (Send packet | Reply packet)
854 * Once complete, we copy the contents of the temporary packet over the original
855 * SCTP packet we were asked to NAT
857 * @param la Pointer to the relevant libalias instance
858 * @param sm Pointer to sctp message information
859 * @param assoc Pointer to current association details
860 * @param sndrply SN_SEND_ABORT | SN_REPLY_ABORT | SN_REPLY_ERROR
861 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
864 local_sctp_finalize_crc32(uint32_t crc32c)
866 /* This routine is duplicated from SCTP
867 * we need to do that since it MAY be that SCTP
868 * is NOT compiled into the kernel. The CRC32C routines
869 * however are always available in libkern.
872 #if BYTE_ORDER == BIG_ENDIAN
873 uint8_t byte0, byte1, byte2, byte3;
876 /* Complement the result */
878 #if BYTE_ORDER == BIG_ENDIAN
880 * For BIG-ENDIAN.. aka Motorola byte order the result is in
881 * little-endian form. So we must manually swap the bytes. Then we
882 * can call htonl() which does nothing...
884 byte0 = result & 0x000000ff;
885 byte1 = (result >> 8) & 0x000000ff;
886 byte2 = (result >> 16) & 0x000000ff;
887 byte3 = (result >> 24) & 0x000000ff;
888 crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3);
891 * For INTEL platforms the result comes out in network order. No
892 * htonl is required or the swap above. So we optimize out both the
893 * htonl and the manual swap above.
901 TxAbortErrorM(struct libalias *la, struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int sndrply, int direction)
903 int sctp_size = sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_error_cause);
904 int ip_size = sizeof(struct ip) + sctp_size;
905 int include_error_cause = 1;
906 char tmp_ip[ip_size];
907 char addrbuf[INET_ADDRSTRLEN];
909 if (ntohs(sm->ip_hdr->ip_len) < ip_size) { /* short packet, cannot send error cause */
910 include_error_cause = 0;
911 ip_size = ip_size - sizeof(struct sctp_error_cause);
912 sctp_size = sctp_size - sizeof(struct sctp_error_cause);
914 /* Assign header pointers packet */
915 struct ip* ip = (struct ip *) tmp_ip;
916 struct sctphdr* sctp_hdr = (struct sctphdr *) ((char *) ip + sizeof(*ip));
917 struct sctp_chunkhdr* chunk_hdr = (struct sctp_chunkhdr *) ((char *) sctp_hdr + sizeof(*sctp_hdr));
918 struct sctp_error_cause* error_cause = (struct sctp_error_cause *) ((char *) chunk_hdr + sizeof(*chunk_hdr));
920 /* construct ip header */
921 ip->ip_v = sm->ip_hdr->ip_v;
922 ip->ip_hl = 5; /* 5*32 bit words */
924 ip->ip_len = htons(ip_size);
925 ip->ip_id = sm->ip_hdr->ip_id;
928 ip->ip_p = IPPROTO_SCTP;
930 The definitions below should be removed when they make it into the SCTP stack
932 #define SCTP_MIDDLEBOX_FLAG 0x02
933 #define SCTP_NAT_TABLE_COLLISION 0x00b0
934 #define SCTP_MISSING_NAT 0x00b1
935 chunk_hdr->chunk_type = (sndrply & SN_TX_ABORT) ? SCTP_ABORT_ASSOCIATION : SCTP_OPERATION_ERROR;
936 chunk_hdr->chunk_flags = SCTP_MIDDLEBOX_FLAG;
937 if (include_error_cause) {
938 error_cause->code = htons((sndrply & SN_REFLECT_ERROR) ? SCTP_MISSING_NAT : SCTP_NAT_TABLE_COLLISION);
939 error_cause->length = htons(sizeof(struct sctp_error_cause));
940 chunk_hdr->chunk_length = htons(sizeof(*chunk_hdr) + sizeof(struct sctp_error_cause));
942 chunk_hdr->chunk_length = htons(sizeof(*chunk_hdr));
945 /* set specific values */
947 case SN_REFLECT_ERROR:
948 chunk_hdr->chunk_flags |= SCTP_HAD_NO_TCB; /* set Tbit */
949 sctp_hdr->v_tag = sm->sctp_hdr->v_tag;
952 sctp_hdr->v_tag = (direction == SN_TO_LOCAL) ? assoc->g_vtag : assoc->l_vtag ;
955 sctp_hdr->v_tag = sm->sctp_hdr->v_tag;
958 sctp_hdr->v_tag = sm->sctpchnk.Init->initiate_tag;
962 /* Set send/reply values */
963 if (sndrply == SN_SEND_ABORT) { /*pass through NAT */
964 ip->ip_src = (direction == SN_TO_LOCAL) ? sm->ip_hdr->ip_src : assoc->a_addr;
965 ip->ip_dst = (direction == SN_TO_LOCAL) ? assoc->l_addr : sm->ip_hdr->ip_dst;
966 sctp_hdr->src_port = sm->sctp_hdr->src_port;
967 sctp_hdr->dest_port = sm->sctp_hdr->dest_port;
968 } else { /* reply and reflect */
969 ip->ip_src = sm->ip_hdr->ip_dst;
970 ip->ip_dst = sm->ip_hdr->ip_src;
971 sctp_hdr->src_port = sm->sctp_hdr->dest_port;
972 sctp_hdr->dest_port = sm->sctp_hdr->src_port;
975 /* Calculate IP header checksum */
976 ip->ip_sum = in_cksum_hdr(ip);
978 /* calculate SCTP header CRC32 */
979 sctp_hdr->checksum = 0;
980 sctp_hdr->checksum = local_sctp_finalize_crc32(calculate_crc32c(0xffffffff, (unsigned char *) sctp_hdr, sctp_size));
982 memcpy(sm->ip_hdr, ip, ip_size);
984 SN_LOG(SN_LOG_EVENT,SctpAliasLog("%s %s 0x%x (->%s:%u vtag=0x%x crc=0x%x)\n",
985 ((sndrply == SN_SEND_ABORT) ? "Sending" : "Replying"),
986 ((sndrply & SN_TX_ERROR) ? "ErrorM" : "AbortM"),
987 (include_error_cause ? ntohs(error_cause->code) : 0),
988 inet_ntoa_r(ip->ip_dst, INET_NTOA_BUF(addrbuf)),
989 ntohs(sctp_hdr->dest_port),
990 ntohl(sctp_hdr->v_tag), ntohl(sctp_hdr->checksum)));
993 /* ----------------------------------------------------------------------
995 * ----------------------------------------------------------------------
997 /** @addtogroup packet_parser
999 * These functions parse the SCTP packet and fill a sctp_nat_msg structure
1000 * with the parsed contents.
1002 /** @ingroup packet_parser
1003 * @brief Parses SCTP packets for the key SCTP chunk that will be processed
1005 * This module parses SCTP packets for the key SCTP chunk that will be processed
1006 * The module completes the sctp_nat_msg structure and either retrieves the
1007 * relevant (existing) stored association from the Hash Tables or creates a new
1008 * association entity with state SN_ID
1010 * @param la Pointer to the relevant libalias instance
1011 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1013 * @param sm Pointer to sctp message information
1014 * @param passoc Pointer to the association this SCTP Message belongs to
1016 * @return SN_PARSE_OK | SN_PARSE_ERROR_*
1019 sctp_PktParser(struct libalias *la, int direction, struct ip *pip,
1020 struct sctp_nat_msg *sm, struct sctp_nat_assoc **passoc)
1021 //sctp_PktParser(int direction, struct mbuf *ipak, int ip_hdr_len,struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc)
1023 struct sctphdr *sctp_hdr;
1024 struct sctp_chunkhdr *chunk_hdr;
1025 struct sctp_paramhdr *param_hdr;
1026 struct in_addr ipv4addr;
1027 int bytes_left; /* bytes left in ip packet */
1030 int partial_match = 0;
1034 // mlen = SCTP_HEADER_LEN(i_pak);
1035 // mp = SCTP_HEADER_TO_CHAIN(i_pak); /* does nothing in bsd since header and chain not separate */
1038 * Note, that if the VTag is zero, it must be an INIT
1039 * Also, I am only interested in the content of INIT and ADDIP chunks
1042 // no mbuf stuff from Paolo yet so ...
1044 /* remove ip header length from the bytes_left */
1045 bytes_left = ntohs(pip->ip_len) - (pip->ip_hl << 2);
1047 /* Check SCTP header length and move to first chunk */
1048 if (bytes_left < sizeof(struct sctphdr)) {
1049 sm->sctp_hdr = NULL;
1050 return(SN_PARSE_ERROR_IPSHL); /* packet not long enough*/
1053 sm->sctp_hdr = sctp_hdr = (struct sctphdr *) ip_next(pip);
1054 bytes_left -= sizeof(struct sctphdr);
1056 /* Check for valid ports (zero valued ports would find partially initialised associations */
1057 if (sctp_hdr->src_port == 0 || sctp_hdr->dest_port == 0)
1058 return(SN_PARSE_ERROR_PORT);
1060 /* Check length of first chunk */
1061 if (bytes_left < SN_MIN_CHUNK_SIZE) /* malformed chunk - could cause endless loop*/
1062 return(SN_PARSE_ERROR_CHHL); /* packet not long enough for this chunk */
1065 chunk_hdr = SN_SCTP_FIRSTCHUNK(sctp_hdr);
1067 chunk_length = SCTP_SIZE32(ntohs(chunk_hdr->chunk_length));
1068 if ((chunk_length < SN_MIN_CHUNK_SIZE) || (chunk_length > bytes_left)) /* malformed chunk - could cause endless loop*/
1069 return(SN_PARSE_ERROR_CHHL);
1071 if ((chunk_hdr->chunk_flags & SCTP_HAD_NO_TCB) &&
1072 ((chunk_hdr->chunk_type == SCTP_ABORT_ASSOCIATION) ||
1073 (chunk_hdr->chunk_type == SCTP_SHUTDOWN_COMPLETE))) {
1075 if (direction == SN_TO_LOCAL)
1076 *passoc = FindSctpGlobalT(la, pip->ip_src, sctp_hdr->v_tag, sctp_hdr->dest_port, sctp_hdr->src_port);
1078 *passoc = FindSctpLocalT(la, pip->ip_dst, sctp_hdr->v_tag, sctp_hdr->dest_port, sctp_hdr->src_port);
1080 /* Proper v_tag settings */
1081 if (direction == SN_TO_LOCAL)
1082 *passoc = FindSctpGlobal(la, pip->ip_src, sctp_hdr->v_tag, sctp_hdr->src_port, sctp_hdr->dest_port, &partial_match);
1084 *passoc = FindSctpLocal(la, pip->ip_src, pip->ip_dst, sctp_hdr->v_tag, sctp_hdr->src_port, sctp_hdr->dest_port);
1088 /* Real packet parsing occurs below */
1089 sm->msg = SN_SCTP_OTHER;/* Initialise to largest value*/
1090 sm->chunk_length = 0; /* only care about length for key chunks */
1091 while (IS_SCTP_CONTROL(chunk_hdr)) {
1092 switch(chunk_hdr->chunk_type) {
1093 case SCTP_INITIATION:
1094 if (chunk_length < sizeof(struct sctp_init_chunk)) /* malformed chunk*/
1095 return(SN_PARSE_ERROR_CHHL);
1096 sm->msg = SN_SCTP_INIT;
1097 sm->sctpchnk.Init = (struct sctp_init *) ((char *) chunk_hdr + sizeof(struct sctp_chunkhdr));
1098 sm->chunk_length = chunk_length;
1099 /* if no existing association, create a new one */
1100 if (*passoc == NULL) {
1101 if (sctp_hdr->v_tag == 0){ //Init requires vtag=0
1102 *passoc = (struct sctp_nat_assoc *) sn_malloc(sizeof(struct sctp_nat_assoc));
1103 if (*passoc == NULL) {/* out of resources */
1104 return(SN_PARSE_ERROR_AS_MALLOC);
1106 /* Initialise association - malloc initialises memory to zeros */
1107 (*passoc)->state = SN_ID;
1108 LIST_INIT(&((*passoc)->Gaddr)); /* always initialise to avoid memory problems */
1109 (*passoc)->TableRegister = SN_NULL_TBL;
1110 return(SN_PARSE_OK);
1112 return(SN_PARSE_ERROR_VTAG);
1114 return(SN_PARSE_ERROR_LOOKUP);
1115 case SCTP_INITIATION_ACK:
1116 if (chunk_length < sizeof(struct sctp_init_ack_chunk)) /* malformed chunk*/
1117 return(SN_PARSE_ERROR_CHHL);
1118 sm->msg = SN_SCTP_INITACK;
1119 sm->sctpchnk.InitAck = (struct sctp_init_ack *) ((char *) chunk_hdr + sizeof(struct sctp_chunkhdr));
1120 sm->chunk_length = chunk_length;
1121 return ((*passoc == NULL)?(SN_PARSE_ERROR_LOOKUP):(SN_PARSE_OK));
1122 case SCTP_ABORT_ASSOCIATION: /* access only minimum sized chunk */
1123 sm->msg = SN_SCTP_ABORT;
1124 sm->chunk_length = chunk_length;
1125 return ((*passoc == NULL)?(SN_PARSE_ERROR_LOOKUP_ABORT):(SN_PARSE_OK));
1126 case SCTP_SHUTDOWN_ACK:
1127 if (chunk_length < sizeof(struct sctp_shutdown_ack_chunk)) /* malformed chunk*/
1128 return(SN_PARSE_ERROR_CHHL);
1129 if (sm->msg > SN_SCTP_SHUTACK) {
1130 sm->msg = SN_SCTP_SHUTACK;
1131 sm->chunk_length = chunk_length;
1134 case SCTP_SHUTDOWN_COMPLETE: /* minimum sized chunk */
1135 if (sm->msg > SN_SCTP_SHUTCOMP) {
1136 sm->msg = SN_SCTP_SHUTCOMP;
1137 sm->chunk_length = chunk_length;
1139 return ((*passoc == NULL)?(SN_PARSE_ERROR_LOOKUP):(SN_PARSE_OK));
1141 if (sm->msg > SN_SCTP_ASCONF) {
1142 if (chunk_length < (sizeof(struct sctp_asconf_chunk) + sizeof(struct sctp_ipv4addr_param))) /* malformed chunk*/
1143 return(SN_PARSE_ERROR_CHHL);
1144 //leave parameter searching to later, if required
1145 param_hdr = (struct sctp_paramhdr *) ((char *) chunk_hdr + sizeof(struct sctp_asconf_chunk)); /*compulsory IP parameter*/
1146 if (ntohs(param_hdr->param_type) == SCTP_IPV4_ADDRESS) {
1147 if ((*passoc == NULL) && (direction == SN_TO_LOCAL)) { /* AddIP with no association */
1148 /* try look up with the ASCONF packet's alternative address */
1149 ipv4addr.s_addr = ((struct sctp_ipv4addr_param *) param_hdr)->addr;
1150 *passoc = FindSctpGlobal(la, ipv4addr, sctp_hdr->v_tag, sctp_hdr->src_port, sctp_hdr->dest_port, &partial_match);
1152 param_hdr = (struct sctp_paramhdr *)
1153 ((char *) param_hdr + sizeof(struct sctp_ipv4addr_param)); /*asconf's compulsory address parameter */
1154 sm->chunk_length = chunk_length - sizeof(struct sctp_asconf_chunk) - sizeof(struct sctp_ipv4addr_param); /* rest of chunk */
1156 if (chunk_length < (sizeof(struct sctp_asconf_chunk) + sizeof(struct sctp_ipv6addr_param))) /* malformed chunk*/
1157 return(SN_PARSE_ERROR_CHHL);
1158 param_hdr = (struct sctp_paramhdr *)
1159 ((char *) param_hdr + sizeof(struct sctp_ipv6addr_param)); /*asconf's compulsory address parameter */
1160 sm->chunk_length = chunk_length - sizeof(struct sctp_asconf_chunk) - sizeof(struct sctp_ipv6addr_param); /* rest of chunk */
1162 sm->msg = SN_SCTP_ASCONF;
1163 sm->sctpchnk.Asconf = param_hdr;
1165 if (*passoc == NULL) { /* AddIP with no association */
1166 *passoc = (struct sctp_nat_assoc *) sn_malloc(sizeof(struct sctp_nat_assoc));
1167 if (*passoc == NULL) {/* out of resources */
1168 return(SN_PARSE_ERROR_AS_MALLOC);
1170 /* Initialise association - malloc initialises memory to zeros */
1171 (*passoc)->state = SN_ID;
1172 LIST_INIT(&((*passoc)->Gaddr)); /* always initialise to avoid memory problems */
1173 (*passoc)->TableRegister = SN_NULL_TBL;
1174 return(SN_PARSE_OK);
1178 case SCTP_ASCONF_ACK:
1179 if (sm->msg > SN_SCTP_ASCONFACK) {
1180 if (chunk_length < sizeof(struct sctp_asconf_ack_chunk)) /* malformed chunk*/
1181 return(SN_PARSE_ERROR_CHHL);
1182 //leave parameter searching to later, if required
1183 param_hdr = (struct sctp_paramhdr *) ((char *) chunk_hdr
1184 + sizeof(struct sctp_asconf_ack_chunk));
1185 sm->msg = SN_SCTP_ASCONFACK;
1186 sm->sctpchnk.Asconf = param_hdr;
1187 sm->chunk_length = chunk_length - sizeof(struct sctp_asconf_ack_chunk);
1191 break; /* do nothing*/
1194 /* if no association is found exit - we need to find an Init or AddIP within sysctl_initialising_chunk_proc_limit */
1195 if ((*passoc == NULL) && (chunk_count >= sysctl_initialising_chunk_proc_limit))
1196 return(SN_PARSE_ERROR_LOOKUP);
1198 /* finished with this chunk, on to the next chunk*/
1199 bytes_left-= chunk_length;
1201 /* Is this the end of the packet ? */
1202 if (bytes_left == 0)
1203 return (*passoc == NULL)?(SN_PARSE_ERROR_LOOKUP):(SN_PARSE_OK);
1205 /* Are there enough bytes in packet to at least retrieve length of next chunk ? */
1206 if (bytes_left < SN_MIN_CHUNK_SIZE)
1207 return(SN_PARSE_ERROR_CHHL);
1209 chunk_hdr = SN_SCTP_NEXTCHUNK(chunk_hdr);
1211 /* Is the chunk long enough to not cause endless look and are there enough bytes in packet to read the chunk ? */
1212 chunk_length = SCTP_SIZE32(ntohs(chunk_hdr->chunk_length));
1213 if ((chunk_length < SN_MIN_CHUNK_SIZE) || (chunk_length > bytes_left))
1214 return(SN_PARSE_ERROR_CHHL);
1215 if(++chunk_count > sysctl_chunk_proc_limit)
1216 return(SN_PARSE_OK); /* limit for processing chunks, take what we get */
1219 if (*passoc == NULL)
1220 return (partial_match)?(SN_PARSE_ERROR_PARTIALLOOKUP):(SN_PARSE_ERROR_LOOKUP);
1222 return(SN_PARSE_OK);
1225 /** @ingroup packet_parser
1226 * @brief Extract Vtags from Asconf Chunk
1228 * GetAsconfVtags scans an Asconf Chunk for the vtags parameter, and then
1229 * extracts the vtags.
1231 * GetAsconfVtags is not called from within sctp_PktParser. It is called only
1232 * from within ID_process when an AddIP has been received.
1234 * @param la Pointer to the relevant libalias instance
1235 * @param sm Pointer to sctp message information
1236 * @param l_vtag Pointer to the local vtag in the association this SCTP Message belongs to
1237 * @param g_vtag Pointer to the local vtag in the association this SCTP Message belongs to
1238 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1240 * @return 1 - success | 0 - fail
1243 GetAsconfVtags(struct libalias *la, struct sctp_nat_msg *sm, uint32_t *l_vtag, uint32_t *g_vtag, int direction)
1245 /* To be removed when information is in the sctp headers */
1246 #define SCTP_VTAG_PARAM 0xC007
1247 struct sctp_vtag_param {
1248 struct sctp_paramhdr ph;/* type=SCTP_VTAG_PARAM */
1249 uint32_t local_vtag;
1250 uint32_t remote_vtag;
1251 } __attribute__((packed));
1253 struct sctp_vtag_param *vtag_param;
1254 struct sctp_paramhdr *param;
1260 param = sm->sctpchnk.Asconf;
1261 param_size = SCTP_SIZE32(ntohs(param->param_length));
1262 bytes_left = sm->chunk_length;
1263 /* step through Asconf parameters */
1264 while((bytes_left >= param_size) && (bytes_left >= SN_VTAG_PARAM_SIZE)) {
1265 if (ntohs(param->param_type) == SCTP_VTAG_PARAM) {
1266 vtag_param = (struct sctp_vtag_param *) param;
1268 /* The Internet draft is a little ambigious as to order of these vtags.
1269 We think it is this way around. If we are wrong, the order will need
1272 *g_vtag = vtag_param->local_vtag;
1273 *l_vtag = vtag_param->remote_vtag;
1276 *g_vtag = vtag_param->remote_vtag;
1277 *l_vtag = vtag_param->local_vtag;
1280 return(1); /* found */
1283 bytes_left -= param_size;
1284 if (bytes_left < SN_MIN_PARAM_SIZE) return(0);
1286 param = SN_SCTP_NEXTPARAM(param);
1287 param_size = SCTP_SIZE32(ntohs(param->param_length));
1288 if (++param_count > sysctl_param_proc_limit) {
1289 SN_LOG(SN_LOG_EVENT,
1290 logsctperror("Parameter parse limit exceeded (GetAsconfVtags)",
1291 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction));
1292 return(0); /* not found limit exceeded*/
1295 return(0); /* not found */
1298 /** @ingroup packet_parser
1299 * @brief AddGlobalIPAddresses from Init,InitAck,or AddIP packets
1301 * AddGlobalIPAddresses scans an SCTP chunk (in sm) for Global IP addresses, and
1304 * @param sm Pointer to sctp message information
1305 * @param assoc Pointer to the association this SCTP Message belongs to
1306 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1310 AddGlobalIPAddresses(struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int direction)
1312 struct sctp_ipv4addr_param *ipv4_param;
1313 struct sctp_paramhdr *param = NULL;
1314 struct sctp_GlobalAddress *G_Addr;
1315 struct in_addr g_addr = {0};
1318 int param_count, addr_param_count = 0;
1321 case SN_TO_GLOBAL: /* does not contain global addresses */
1322 g_addr = sm->ip_hdr->ip_dst;
1323 bytes_left = 0; /* force exit */
1326 g_addr = sm->ip_hdr->ip_src;
1330 bytes_left = sm->chunk_length - sizeof(struct sctp_init_chunk);
1331 param = (struct sctp_paramhdr *)((char *)sm->sctpchnk.Init + sizeof(struct sctp_init));
1333 case SN_SCTP_INITACK:
1334 bytes_left = sm->chunk_length - sizeof(struct sctp_init_ack_chunk);
1335 param = (struct sctp_paramhdr *)((char *)sm->sctpchnk.InitAck + sizeof(struct sctp_init_ack));
1337 case SN_SCTP_ASCONF:
1338 bytes_left = sm->chunk_length;
1339 param = sm->sctpchnk.Asconf;
1343 if (bytes_left >= SN_MIN_PARAM_SIZE)
1344 param_size = SCTP_SIZE32(ntohs(param->param_length));
1346 param_size = bytes_left+1; /* force skip loop */
1348 if ((assoc->state == SN_ID) && ((sm->msg == SN_SCTP_INIT) || (bytes_left < SN_MIN_PARAM_SIZE))) {/* add pkt address */
1349 G_Addr = (struct sctp_GlobalAddress *) sn_malloc(sizeof(struct sctp_GlobalAddress));
1350 if (G_Addr == NULL) {/* out of resources */
1351 SN_LOG(SN_LOG_EVENT,
1352 logsctperror("AddGlobalIPAddress: No resources for adding global address - revert to no tracking",
1353 sm->sctp_hdr->v_tag, 0, direction));
1354 assoc->num_Gaddr = 0; /* don't track any more for this assoc*/
1355 sysctl_track_global_addresses=0;
1358 G_Addr->g_addr = g_addr;
1359 if (!Add_Global_Address_to_List(assoc, G_Addr))
1360 SN_LOG(SN_LOG_EVENT,
1361 logsctperror("AddGlobalIPAddress: Address already in list",
1362 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction));
1365 /* step through parameters */
1366 while((bytes_left >= param_size) && (bytes_left >= sizeof(struct sctp_ipv4addr_param))) {
1367 if (assoc->num_Gaddr >= sysctl_track_global_addresses) {
1368 SN_LOG(SN_LOG_EVENT,
1369 logsctperror("AddGlobalIPAddress: Maximum Number of addresses reached",
1370 sm->sctp_hdr->v_tag, sysctl_track_global_addresses, direction));
1373 switch(ntohs(param->param_type)) {
1374 case SCTP_ADD_IP_ADDRESS:
1375 /* skip to address parameter - leave param_size so bytes left will be calculated properly*/
1376 param = (struct sctp_paramhdr *) &((struct sctp_asconf_addrv4_param *) param)->addrp;
1377 case SCTP_IPV4_ADDRESS:
1378 ipv4_param = (struct sctp_ipv4addr_param *) param;
1379 /* add addresses to association */
1380 G_Addr = (struct sctp_GlobalAddress *) sn_malloc(sizeof(struct sctp_GlobalAddress));
1381 if (G_Addr == NULL) {/* out of resources */
1382 SN_LOG(SN_LOG_EVENT,
1383 logsctperror("AddGlobalIPAddress: No resources for adding global address - revert to no tracking",
1384 sm->sctp_hdr->v_tag, 0, direction));
1385 assoc->num_Gaddr = 0; /* don't track any more for this assoc*/
1386 sysctl_track_global_addresses=0;
1391 if ((sm->msg == SN_SCTP_ASCONF) && (ipv4_param->addr == INADDR_ANY)) { /* use packet address */
1392 G_Addr->g_addr = g_addr;
1393 if (!Add_Global_Address_to_List(assoc, G_Addr))
1394 SN_LOG(SN_LOG_EVENT,
1395 logsctperror("AddGlobalIPAddress: Address already in list",
1396 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction));
1397 return; /*shouldn't be any other addresses if the zero address is given*/
1399 G_Addr->g_addr.s_addr = ipv4_param->addr;
1400 if (!Add_Global_Address_to_List(assoc, G_Addr))
1401 SN_LOG(SN_LOG_EVENT,
1402 logsctperror("AddGlobalIPAddress: Address already in list",
1403 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction));
1407 bytes_left -= param_size;
1408 if (bytes_left < SN_MIN_PARAM_SIZE)
1411 param = SN_SCTP_NEXTPARAM(param);
1412 param_size = SCTP_SIZE32(ntohs(param->param_length));
1413 if (++param_count > sysctl_param_proc_limit) {
1414 SN_LOG(SN_LOG_EVENT,
1415 logsctperror("Parameter parse limit exceeded (AddGlobalIPAddress)",
1416 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction));
1417 break; /* limit exceeded*/
1420 if (addr_param_count == 0) {
1421 SN_LOG(SN_LOG_DETAIL,
1422 logsctperror("AddGlobalIPAddress: no address parameters to add",
1423 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction));
1428 * @brief Add_Global_Address_to_List
1430 * Adds a global IP address to an associations address list, if it is not
1431 * already there. The first address added us usually the packet's address, and
1432 * is most likely to be used, so it is added at the beginning. Subsequent
1433 * addresses are added after this one.
1435 * @param assoc Pointer to the association this SCTP Message belongs to
1436 * @param G_addr Pointer to the global address to add
1438 * @return 1 - success | 0 - fail
1440 static int Add_Global_Address_to_List(struct sctp_nat_assoc *assoc, struct sctp_GlobalAddress *G_addr)
1442 struct sctp_GlobalAddress *iter_G_Addr = NULL, *first_G_Addr = NULL;
1443 first_G_Addr = LIST_FIRST(&(assoc->Gaddr));
1444 if (first_G_Addr == NULL) {
1445 LIST_INSERT_HEAD(&(assoc->Gaddr), G_addr, list_Gaddr); /* add new address to beginning of list*/
1447 LIST_FOREACH(iter_G_Addr, &(assoc->Gaddr), list_Gaddr) {
1448 if (G_addr->g_addr.s_addr == iter_G_Addr->g_addr.s_addr)
1449 return(0); /* already exists, so don't add */
1451 LIST_INSERT_AFTER(first_G_Addr, G_addr, list_Gaddr); /* add address to end of list*/
1454 return(1); /* success */
1457 /** @ingroup packet_parser
1458 * @brief RmGlobalIPAddresses from DelIP packets
1460 * RmGlobalIPAddresses scans an ASCONF chunk for DelIP parameters to remove the
1461 * given Global IP addresses from the association. It will not delete the
1462 * the address if it is a list of one address.
1465 * @param sm Pointer to sctp message information
1466 * @param assoc Pointer to the association this SCTP Message belongs to
1467 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1471 RmGlobalIPAddresses(struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc, int direction)
1473 struct sctp_asconf_addrv4_param *asconf_ipv4_param;
1474 struct sctp_paramhdr *param;
1475 struct sctp_GlobalAddress *G_Addr, *G_Addr_tmp;
1476 struct in_addr g_addr;
1481 if(direction == SN_TO_GLOBAL)
1482 g_addr = sm->ip_hdr->ip_dst;
1484 g_addr = sm->ip_hdr->ip_src;
1486 bytes_left = sm->chunk_length;
1488 param = sm->sctpchnk.Asconf;
1489 if (bytes_left >= SN_MIN_PARAM_SIZE) {
1490 param_size = SCTP_SIZE32(ntohs(param->param_length));
1492 SN_LOG(SN_LOG_EVENT,
1493 logsctperror("RmGlobalIPAddress: truncated packet - cannot remove IP addresses",
1494 sm->sctp_hdr->v_tag, sysctl_track_global_addresses, direction));
1498 /* step through Asconf parameters */
1499 while((bytes_left >= param_size) && (bytes_left >= sizeof(struct sctp_ipv4addr_param))) {
1500 if (ntohs(param->param_type) == SCTP_DEL_IP_ADDRESS) {
1501 asconf_ipv4_param = (struct sctp_asconf_addrv4_param *) param;
1502 if (asconf_ipv4_param->addrp.addr == INADDR_ANY) { /* remove all bar pkt address */
1503 LIST_FOREACH_SAFE(G_Addr, &(assoc->Gaddr), list_Gaddr, G_Addr_tmp) {
1504 if(G_Addr->g_addr.s_addr != sm->ip_hdr->ip_src.s_addr) {
1505 if (assoc->num_Gaddr > 1) { /* only delete if more than one */
1506 LIST_REMOVE(G_Addr, list_Gaddr);
1510 SN_LOG(SN_LOG_EVENT,
1511 logsctperror("RmGlobalIPAddress: Request to remove last IP address (didn't)",
1512 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction));
1516 return; /*shouldn't be any other addresses if the zero address is given*/
1518 LIST_FOREACH_SAFE(G_Addr, &(assoc->Gaddr), list_Gaddr, G_Addr_tmp) {
1519 if(G_Addr->g_addr.s_addr == asconf_ipv4_param->addrp.addr) {
1520 if (assoc->num_Gaddr > 1) { /* only delete if more than one */
1521 LIST_REMOVE(G_Addr, list_Gaddr);
1524 break; /* Since add only adds new addresses, there should be no double entries */
1526 SN_LOG(SN_LOG_EVENT,
1527 logsctperror("RmGlobalIPAddress: Request to remove last IP address (didn't)",
1528 sm->sctp_hdr->v_tag, assoc->num_Gaddr, direction));
1534 bytes_left -= param_size;
1535 if (bytes_left == 0) return;
1536 else if (bytes_left < SN_MIN_PARAM_SIZE) {
1537 SN_LOG(SN_LOG_EVENT,
1538 logsctperror("RmGlobalIPAddress: truncated packet - may not have removed all IP addresses",
1539 sm->sctp_hdr->v_tag, sysctl_track_global_addresses, direction));
1543 param = SN_SCTP_NEXTPARAM(param);
1544 param_size = SCTP_SIZE32(ntohs(param->param_length));
1545 if (++param_count > sysctl_param_proc_limit) {
1546 SN_LOG(SN_LOG_EVENT,
1547 logsctperror("Parameter parse limit exceeded (RmGlobalIPAddress)",
1548 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction));
1549 return; /* limit exceeded*/
1554 /** @ingroup packet_parser
1555 * @brief Check that ASCONF was successful
1557 * Each ASCONF configuration parameter carries a correlation ID which should be
1558 * matched with an ASCONFack. This is difficult for a NAT, since every
1559 * association could potentially have a number of outstanding ASCONF
1560 * configuration parameters, which should only be activated on receipt of the
1563 * Currently we only look for an ACK when the NAT is setting up a new
1564 * association (ie AddIP for a connection that the NAT does not know about
1565 * because the original Init went through a public interface or another NAT)
1566 * Since there is currently no connection on this path, there should be no other
1567 * ASCONF configuration parameters outstanding, so we presume that if there is
1568 * an ACK that it is responding to the AddIP and activate the new association.
1570 * @param la Pointer to the relevant libalias instance
1571 * @param sm Pointer to sctp message information
1572 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1574 * @return 1 - success | 0 - fail
1577 IsASCONFack(struct libalias *la, struct sctp_nat_msg *sm, int direction)
1579 struct sctp_paramhdr *param;
1585 param = sm->sctpchnk.Asconf;
1586 param_size = SCTP_SIZE32(ntohs(param->param_length));
1587 if (param_size == 8)
1588 return(1); /*success - default acknowledgement of everything */
1590 bytes_left = sm->chunk_length;
1591 if (bytes_left < param_size)
1592 return(0); /* not found */
1593 /* step through Asconf parameters */
1594 while(bytes_left >= SN_ASCONFACK_PARAM_SIZE) {
1595 if (ntohs(param->param_type) == SCTP_SUCCESS_REPORT)
1596 return(1); /* success - but can't match correlation IDs - should only be one */
1597 /* check others just in case */
1598 bytes_left -= param_size;
1599 if (bytes_left >= SN_MIN_PARAM_SIZE) {
1600 param = SN_SCTP_NEXTPARAM(param);
1604 param_size = SCTP_SIZE32(ntohs(param->param_length));
1605 if (bytes_left < param_size) return(0);
1607 if (++param_count > sysctl_param_proc_limit) {
1608 SN_LOG(SN_LOG_EVENT,
1609 logsctperror("Parameter parse limit exceeded (IsASCONFack)",
1610 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction));
1611 return(0); /* not found limit exceeded*/
1614 return(0); /* not success */
1617 /** @ingroup packet_parser
1618 * @brief Check to see if ASCONF contains an Add IP or Del IP parameter
1620 * IsADDorDEL scans an ASCONF packet to see if it contains an AddIP or DelIP
1623 * @param la Pointer to the relevant libalias instance
1624 * @param sm Pointer to sctp message information
1625 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1627 * @return SCTP_ADD_IP_ADDRESS | SCTP_DEL_IP_ADDRESS | 0 - fail
1630 IsADDorDEL(struct libalias *la, struct sctp_nat_msg *sm, int direction)
1632 struct sctp_paramhdr *param;
1638 param = sm->sctpchnk.Asconf;
1639 param_size = SCTP_SIZE32(ntohs(param->param_length));
1641 bytes_left = sm->chunk_length;
1642 if (bytes_left < param_size)
1643 return(0); /* not found */
1644 /* step through Asconf parameters */
1645 while(bytes_left >= SN_ASCONFACK_PARAM_SIZE) {
1646 if (ntohs(param->param_type) == SCTP_ADD_IP_ADDRESS)
1647 return(SCTP_ADD_IP_ADDRESS);
1648 else if (ntohs(param->param_type) == SCTP_DEL_IP_ADDRESS)
1649 return(SCTP_DEL_IP_ADDRESS);
1650 /* check others just in case */
1651 bytes_left -= param_size;
1652 if (bytes_left >= SN_MIN_PARAM_SIZE) {
1653 param = SN_SCTP_NEXTPARAM(param);
1655 return(0); /*Neither found */
1657 param_size = SCTP_SIZE32(ntohs(param->param_length));
1658 if (bytes_left < param_size) return(0);
1660 if (++param_count > sysctl_param_proc_limit) {
1661 SN_LOG(SN_LOG_EVENT,
1662 logsctperror("Parameter parse limit exceeded IsADDorDEL)",
1663 sm->sctp_hdr->v_tag, sysctl_param_proc_limit, direction));
1664 return(0); /* not found limit exceeded*/
1667 return(0); /*Neither found */
1670 /* ----------------------------------------------------------------------
1671 * STATE MACHINE CODE
1672 * ----------------------------------------------------------------------
1674 /** @addtogroup state_machine
1676 * The SCTP NAT State Machine functions will:
1677 * - Process an already parsed packet
1678 * - Use the existing NAT Hash Tables
1679 * - Determine the next state for the association
1680 * - Update the NAT Hash Tables and Timer Queues
1681 * - Return the appropriate action to take with the packet
1683 /** @ingroup state_machine
1684 * @brief Process SCTP message
1686 * This function is the base state machine. It calls the processing engine for
1689 * @param la Pointer to the relevant libalias instance
1690 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1691 * @param sm Pointer to sctp message information
1692 * @param assoc Pointer to the association this SCTP Message belongs to
1694 * @return SN_DROP_PKT | SN_NAT_PKT | SN_REPLY_ABORT | SN_REPLY_ERROR | SN_PROCESSING_ERROR
1697 ProcessSctpMsg(struct libalias *la, int direction, struct sctp_nat_msg *sm, struct sctp_nat_assoc *assoc)
1701 switch (assoc->state) {
1702 case SN_ID: /* Idle */
1703 rtnval = ID_process(la, direction, assoc, sm);
1704 if (rtnval != SN_NAT_PKT) {
1705 assoc->state = SN_RM;/* Mark for removal*/
1708 case SN_INi: /* Initialising - Init */
1709 return(INi_process(la, direction, assoc, sm));
1710 case SN_INa: /* Initialising - AddIP */
1711 return(INa_process(la, direction, assoc, sm));
1712 case SN_UP: /* Association UP */
1713 return(UP_process(la, direction, assoc, sm));
1714 case SN_CL: /* Association Closing */
1715 return(CL_process(la, direction, assoc, sm));
1717 return(SN_PROCESSING_ERROR);
1720 /** @ingroup state_machine
1721 * @brief Process SCTP message while in the Idle state
1723 * This function looks for an Incoming INIT or AddIP message.
1725 * All other SCTP messages are invalid when in SN_ID, and are dropped.
1727 * @param la Pointer to the relevant libalias instance
1728 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1729 * @param sm Pointer to sctp message information
1730 * @param assoc Pointer to the association this SCTP Message belongs to
1732 * @return SN_NAT_PKT | SN_DROP_PKT | SN_REPLY_ABORT | SN_REPLY_ERROR
1735 ID_process(struct libalias *la, int direction, struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm)
1738 case SN_SCTP_ASCONF: /* a packet containing an ASCONF chunk with ADDIP */
1739 if (!sysctl_accept_global_ootb_addip && (direction == SN_TO_LOCAL))
1740 return(SN_DROP_PKT);
1741 /* if this Asconf packet does not contain the Vtag parameters it is of no use in Idle state */
1742 if (!GetAsconfVtags(la, sm, &(assoc->l_vtag), &(assoc->g_vtag), direction))
1743 return(SN_DROP_PKT);
1744 case SN_SCTP_INIT: /* a packet containing an INIT chunk or an ASCONF AddIP */
1745 if (sysctl_track_global_addresses)
1746 AddGlobalIPAddresses(sm, assoc, direction);
1749 assoc->l_addr = sm->ip_hdr->ip_src;
1750 assoc->a_addr = FindAliasAddress(la, assoc->l_addr);
1751 assoc->l_port = sm->sctp_hdr->src_port;
1752 assoc->g_port = sm->sctp_hdr->dest_port;
1753 if(sm->msg == SN_SCTP_INIT)
1754 assoc->g_vtag = sm->sctpchnk.Init->initiate_tag;
1755 if (AddSctpAssocGlobal(la, assoc)) /* DB clash *///**** need to add dst address
1756 return((sm->msg == SN_SCTP_INIT) ? SN_REPLY_ABORT : SN_REPLY_ERROR);
1757 if(sm->msg == SN_SCTP_ASCONF) {
1758 if (AddSctpAssocLocal(la, assoc, sm->ip_hdr->ip_dst)) /* DB clash */
1759 return(SN_REPLY_ERROR);
1760 assoc->TableRegister |= SN_WAIT_TOLOCAL; /* wait for tolocal ack */
1764 assoc->l_addr = FindSctpRedirectAddress(la, sm);
1765 assoc->a_addr = sm->ip_hdr->ip_dst;
1766 assoc->l_port = sm->sctp_hdr->dest_port;
1767 assoc->g_port = sm->sctp_hdr->src_port;
1768 if(sm->msg == SN_SCTP_INIT)
1769 assoc->l_vtag = sm->sctpchnk.Init->initiate_tag;
1770 if (AddSctpAssocLocal(la, assoc, sm->ip_hdr->ip_src)) /* DB clash */
1771 return((sm->msg == SN_SCTP_INIT) ? SN_REPLY_ABORT : SN_REPLY_ERROR);
1772 if(sm->msg == SN_SCTP_ASCONF) {
1773 if (AddSctpAssocGlobal(la, assoc)) /* DB clash */ //**** need to add src address
1774 return(SN_REPLY_ERROR);
1775 assoc->TableRegister |= SN_WAIT_TOGLOBAL; /* wait for toglobal ack */
1779 assoc->state = (sm->msg == SN_SCTP_INIT) ? SN_INi : SN_INa;
1780 assoc->exp = SN_I_T(la);
1781 sctp_AddTimeOut(la,assoc);
1783 default: /* Any other type of SCTP message is not valid in Idle */
1784 return(SN_DROP_PKT);
1786 return(SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */
1789 /** @ingroup state_machine
1790 * @brief Process SCTP message while waiting for an INIT-ACK message
1792 * Only an INIT-ACK, resent INIT, or an ABORT SCTP packet are valid in this
1793 * state, all other packets are dropped.
1795 * @param la Pointer to the relevant libalias instance
1796 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1797 * @param sm Pointer to sctp message information
1798 * @param assoc Pointer to the association this SCTP Message belongs to
1800 * @return SN_NAT_PKT | SN_DROP_PKT | SN_REPLY_ABORT
1803 INi_process(struct libalias *la, int direction, struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm)
1806 case SN_SCTP_INIT: /* a packet containing a retransmitted INIT chunk */
1807 sctp_ResetTimeOut(la, assoc, SN_I_T(la));
1809 case SN_SCTP_INITACK: /* a packet containing an INIT-ACK chunk */
1812 if (assoc->num_Gaddr) /*If tracking global addresses for this association */
1813 AddGlobalIPAddresses(sm, assoc, direction);
1814 assoc->l_vtag = sm->sctpchnk.Init->initiate_tag;
1815 if (AddSctpAssocLocal(la, assoc, sm->ip_hdr->ip_src)) { /* DB clash */
1816 assoc->state = SN_RM;/* Mark for removal*/
1817 return(SN_SEND_ABORT);
1821 assoc->l_addr = sm->ip_hdr->ip_src; // Only if not set in Init! *
1822 assoc->g_vtag = sm->sctpchnk.Init->initiate_tag;
1823 if (AddSctpAssocGlobal(la, assoc)) { /* DB clash */
1824 assoc->state = SN_RM;/* Mark for removal*/
1825 return(SN_SEND_ABORT);
1829 assoc->state = SN_UP;/* association established for NAT */
1830 sctp_ResetTimeOut(la,assoc, SN_U_T(la));
1832 case SN_SCTP_ABORT: /* a packet containing an ABORT chunk */
1833 assoc->state = SN_RM;/* Mark for removal*/
1836 return(SN_DROP_PKT);
1838 return(SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */
1841 /** @ingroup state_machine
1842 * @brief Process SCTP message while waiting for an AddIp-ACK message
1844 * Only an AddIP-ACK, resent AddIP, or an ABORT message are valid, all other
1845 * SCTP packets are dropped
1847 * @param la Pointer to the relevant libalias instance
1848 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1849 * @param sm Pointer to sctp message information
1850 * @param assoc Pointer to the association this SCTP Message belongs to
1852 * @return SN_NAT_PKT | SN_DROP_PKT
1855 INa_process(struct libalias *la, int direction,struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm)
1858 case SN_SCTP_ASCONF: /* a packet containing an ASCONF chunk*/
1859 sctp_ResetTimeOut(la,assoc, SN_I_T(la));
1861 case SN_SCTP_ASCONFACK: /* a packet containing an ASCONF chunk with a ADDIP-ACK */
1864 if (!(assoc->TableRegister & SN_WAIT_TOLOCAL)) /* wrong direction */
1865 return(SN_DROP_PKT);
1868 if (!(assoc->TableRegister & SN_WAIT_TOGLOBAL)) /* wrong direction */
1869 return(SN_DROP_PKT);
1871 if (IsASCONFack(la,sm,direction)) {
1872 assoc->TableRegister &= SN_BOTH_TBL; /* remove wait flags */
1873 assoc->state = SN_UP; /* association established for NAT */
1874 sctp_ResetTimeOut(la,assoc, SN_U_T(la));
1877 assoc->state = SN_RM;/* Mark for removal*/
1880 case SN_SCTP_ABORT: /* a packet containing an ABORT chunk */
1881 assoc->state = SN_RM;/* Mark for removal*/
1884 return(SN_DROP_PKT);
1886 return(SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */
1889 /** @ingroup state_machine
1890 * @brief Process SCTP messages while association is UP redirecting packets
1892 * While in the SN_UP state, all packets for the particular association
1893 * are passed. Only a SHUT-ACK or an ABORT will cause a change of state.
1895 * @param la Pointer to the relevant libalias instance
1896 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1897 * @param sm Pointer to sctp message information
1898 * @param assoc Pointer to the association this SCTP Message belongs to
1900 * @return SN_NAT_PKT | SN_DROP_PKT
1903 UP_process(struct libalias *la, int direction, struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm)
1906 case SN_SCTP_SHUTACK: /* a packet containing a SHUTDOWN-ACK chunk */
1907 assoc->state = SN_CL;
1908 sctp_ResetTimeOut(la,assoc, SN_C_T(la));
1910 case SN_SCTP_ABORT: /* a packet containing an ABORT chunk */
1911 assoc->state = SN_RM;/* Mark for removal*/
1913 case SN_SCTP_ASCONF: /* a packet containing an ASCONF chunk*/
1914 if ((direction == SN_TO_LOCAL) && assoc->num_Gaddr) /*If tracking global addresses for this association & from global side */
1915 switch(IsADDorDEL(la,sm,direction)) {
1916 case SCTP_ADD_IP_ADDRESS:
1917 AddGlobalIPAddresses(sm, assoc, direction);
1919 case SCTP_DEL_IP_ADDRESS:
1920 RmGlobalIPAddresses(sm, assoc, direction);
1922 } /* fall through to default */
1924 sctp_ResetTimeOut(la,assoc, SN_U_T(la));
1925 return(SN_NAT_PKT); /* forward packet */
1927 return(SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */
1930 /** @ingroup state_machine
1931 * @brief Process SCTP message while association is in the process of closing
1933 * This function waits for a SHUT-COMP to close the association. Depending on
1934 * the setting of sysctl_holddown_timer it may not remove the association
1935 * immediately, but leave it up until SN_X_T(la). Only SHUT-COMP, SHUT-ACK, and
1936 * ABORT packets are permitted in this state. All other packets are dropped.
1938 * @param la Pointer to the relevant libalias instance
1939 * @param direction SN_TO_LOCAL | SN_TO_GLOBAL
1940 * @param sm Pointer to sctp message information
1941 * @param assoc Pointer to the association this SCTP Message belongs to
1943 * @return SN_NAT_PKT | SN_DROP_PKT
1946 CL_process(struct libalias *la, int direction,struct sctp_nat_assoc *assoc, struct sctp_nat_msg *sm)
1949 case SN_SCTP_SHUTCOMP: /* a packet containing a SHUTDOWN-COMPLETE chunk */
1950 assoc->state = SN_CL; /* Stay in Close state until timeout */
1951 if (sysctl_holddown_timer > 0)
1952 sctp_ResetTimeOut(la, assoc, SN_X_T(la));/* allow to stay open for Tbit packets*/
1954 assoc->state = SN_RM;/* Mark for removal*/
1956 case SN_SCTP_SHUTACK: /* a packet containing a SHUTDOWN-ACK chunk */
1957 assoc->state = SN_CL; /* Stay in Close state until timeout */
1958 sctp_ResetTimeOut(la, assoc, SN_C_T(la));
1960 case SN_SCTP_ABORT: /* a packet containing an ABORT chunk */
1961 assoc->state = SN_RM;/* Mark for removal*/
1964 return(SN_DROP_PKT);
1966 return(SN_DROP_PKT);/* shouldn't get here very bad: log, drop and hope for the best */
1969 /* ----------------------------------------------------------------------
1971 * ----------------------------------------------------------------------
1973 /** @addtogroup Hash
1975 * The Hash functions facilitate searching the NAT Hash Tables for associations
1976 * as well as adding/removing associations from the table(s).
1979 * @brief Find the SCTP association given the local address, port and vtag
1981 * Searches the local look-up table for the association entry matching the
1982 * provided local <address:ports:vtag> tuple
1984 * @param la Pointer to the relevant libalias instance
1985 * @param l_addr local address
1986 * @param g_addr global address
1987 * @param l_vtag local Vtag
1988 * @param l_port local Port
1989 * @param g_port global Port
1991 * @return pointer to association or NULL
1993 static struct sctp_nat_assoc*
1994 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 struct sctp_nat_assoc *assoc = NULL;
1998 struct sctp_GlobalAddress *G_Addr = NULL;
2000 if (l_vtag != 0) { /* an init packet, vtag==0 */
2001 i = SN_TABLE_HASH(l_vtag, l_port, la->sctpNatTableSize);
2002 LIST_FOREACH(assoc, &la->sctpTableLocal[i], list_L) {
2003 if ((assoc->l_vtag == l_vtag) && (assoc->l_port == l_port) && (assoc->g_port == g_port)\
2004 && (assoc->l_addr.s_addr == l_addr.s_addr)) {
2005 if (assoc->num_Gaddr) {
2006 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) {
2007 if(G_Addr->g_addr.s_addr == g_addr.s_addr)
2020 * @brief Check for Global Clash
2022 * Searches the global look-up table for the association entry matching the
2023 * provided global <(addresses):ports:vtag> tuple
2025 * @param la Pointer to the relevant libalias instance
2026 * @param Cassoc association being checked for a clash
2028 * @return pointer to association or NULL
2030 static struct sctp_nat_assoc*
2031 FindSctpGlobalClash(struct libalias *la, struct sctp_nat_assoc *Cassoc)
2034 struct sctp_nat_assoc *assoc = NULL;
2035 struct sctp_GlobalAddress *G_Addr = NULL;
2036 struct sctp_GlobalAddress *G_AddrC = NULL;
2038 if (Cassoc->g_vtag != 0) { /* an init packet, vtag==0 */
2039 i = SN_TABLE_HASH(Cassoc->g_vtag, Cassoc->g_port, la->sctpNatTableSize);
2040 LIST_FOREACH(assoc, &la->sctpTableGlobal[i], list_G) {
2041 if ((assoc->g_vtag == Cassoc->g_vtag) && (assoc->g_port == Cassoc->g_port) && (assoc->l_port == Cassoc->l_port)) {
2042 if (assoc->num_Gaddr) {
2043 LIST_FOREACH(G_AddrC, &(Cassoc->Gaddr), list_Gaddr) {
2044 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) {
2045 if(G_Addr->g_addr.s_addr == G_AddrC->g_addr.s_addr)
2059 * @brief Find the SCTP association given the global port and vtag
2061 * Searches the global look-up table for the association entry matching the
2062 * provided global <address:ports:vtag> tuple
2064 * If all but the global address match it sets partial_match to 1 to indicate a
2065 * partial match. If the NAT is tracking global IP addresses for this
2066 * association, the NAT may respond with an ERRORM to request the missing
2067 * address to be added.
2069 * @param la Pointer to the relevant libalias instance
2070 * @param g_addr global address
2071 * @param g_vtag global vtag
2072 * @param g_port global port
2073 * @param l_port local port
2075 * @return pointer to association or NULL
2077 static struct sctp_nat_assoc*
2078 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 struct sctp_nat_assoc *assoc = NULL;
2082 struct sctp_GlobalAddress *G_Addr = NULL;
2085 if (g_vtag != 0) { /* an init packet, vtag==0 */
2086 i = SN_TABLE_HASH(g_vtag, g_port, la->sctpNatTableSize);
2087 LIST_FOREACH(assoc, &la->sctpTableGlobal[i], list_G) {
2088 if ((assoc->g_vtag == g_vtag) && (assoc->g_port == g_port) && (assoc->l_port == l_port)) {
2090 if (assoc->num_Gaddr) {
2091 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) {
2092 if(G_Addr->g_addr.s_addr == g_addr.s_addr)
2105 * @brief Find the SCTP association for a T-Flag message (given the global port and local vtag)
2107 * Searches the local look-up table for a unique association entry matching the
2108 * provided global port and local vtag information
2110 * @param la Pointer to the relevant libalias instance
2111 * @param g_addr global address
2112 * @param l_vtag local Vtag
2113 * @param g_port global Port
2114 * @param l_port local Port
2116 * @return pointer to association or NULL
2118 static struct sctp_nat_assoc*
2119 FindSctpLocalT(struct libalias *la, struct in_addr g_addr, uint32_t l_vtag, uint16_t g_port, uint16_t l_port)
2122 struct sctp_nat_assoc *assoc = NULL, *lastmatch = NULL;
2123 struct sctp_GlobalAddress *G_Addr = NULL;
2126 if (l_vtag != 0) { /* an init packet, vtag==0 */
2127 i = SN_TABLE_HASH(l_vtag, g_port, la->sctpNatTableSize);
2128 LIST_FOREACH(assoc, &la->sctpTableGlobal[i], list_G) {
2129 if ((assoc->g_vtag == l_vtag) && (assoc->g_port == g_port) && (assoc->l_port == l_port)) {
2130 if (assoc->num_Gaddr) {
2131 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) {
2132 if(G_Addr->g_addr.s_addr == G_Addr->g_addr.s_addr)
2133 return(assoc); /* full match */
2136 if (++cnt > 1) return(NULL);
2142 /* If there is more than one match we do not know which local address to send to */
2143 return( cnt ? lastmatch : NULL );
2147 * @brief Find the SCTP association for a T-Flag message (given the local port and global vtag)
2149 * Searches the global look-up table for a unique association entry matching the
2150 * provided local port and global vtag information
2152 * @param la Pointer to the relevant libalias instance
2153 * @param g_addr global address
2154 * @param g_vtag global vtag
2155 * @param l_port local port
2156 * @param g_port global port
2158 * @return pointer to association or NULL
2160 static struct sctp_nat_assoc*
2161 FindSctpGlobalT(struct libalias *la, struct in_addr g_addr, uint32_t g_vtag, uint16_t l_port, uint16_t g_port)
2164 struct sctp_nat_assoc *assoc = NULL;
2165 struct sctp_GlobalAddress *G_Addr = NULL;
2167 if (g_vtag != 0) { /* an init packet, vtag==0 */
2168 i = SN_TABLE_HASH(g_vtag, l_port, la->sctpNatTableSize);
2169 LIST_FOREACH(assoc, &la->sctpTableLocal[i], list_L) {
2170 if ((assoc->l_vtag == g_vtag) && (assoc->l_port == l_port) && (assoc->g_port == g_port)) {
2171 if (assoc->num_Gaddr) {
2172 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) {
2173 if(G_Addr->g_addr.s_addr == g_addr.s_addr)
2186 * @brief Add the sctp association information to the local look up table
2188 * Searches the local look-up table for an existing association with the same
2189 * details. If a match exists and is ONLY in the local look-up table then this
2190 * is a repeated INIT packet, we need to remove this association from the
2191 * look-up table and add the new association
2193 * The new association is added to the head of the list and state is updated
2195 * @param la Pointer to the relevant libalias instance
2196 * @param assoc pointer to sctp association
2197 * @param g_addr global address
2199 * @return SN_ADD_OK | SN_ADD_CLASH
2202 AddSctpAssocLocal(struct libalias *la, struct sctp_nat_assoc *assoc, struct in_addr g_addr)
2204 struct sctp_nat_assoc *found;
2206 LIBALIAS_LOCK_ASSERT(la);
2207 found = FindSctpLocal(la, assoc->l_addr, g_addr, assoc->l_vtag, assoc->l_port, assoc->g_port);
2209 * Note that if a different global address initiated this Init,
2210 * ie it wasn't resent as presumed:
2211 * - the local receiver if receiving it for the first time will establish
2212 * an association with the new global host
2213 * - if receiving an init from a different global address after sending a
2214 * lost initack it will send an initack to the new global host, the first
2215 * association attempt will then be blocked if retried.
2217 if (found != NULL) {
2218 if ((found->TableRegister == SN_LOCAL_TBL) && (found->g_port == assoc->g_port)) { /* resent message */
2219 RmSctpAssoc(la, found);
2220 sctp_RmTimeOut(la, found);
2221 freeGlobalAddressList(found);
2224 return(SN_ADD_CLASH);
2227 LIST_INSERT_HEAD(&la->sctpTableLocal[SN_TABLE_HASH(assoc->l_vtag, assoc->l_port, la->sctpNatTableSize)],
2229 assoc->TableRegister |= SN_LOCAL_TBL;
2230 la->sctpLinkCount++; //increment link count
2232 if (assoc->TableRegister == SN_BOTH_TBL) {
2233 /* libalias log -- controlled by libalias */
2234 if (la->packetAliasMode & PKT_ALIAS_LOG)
2235 SctpShowAliasStats(la);
2237 SN_LOG(SN_LOG_INFO, logsctpassoc(assoc, "^"));
2244 * @brief Add the sctp association information to the global look up table
2246 * Searches the global look-up table for an existing association with the same
2247 * details. If a match exists and is ONLY in the global look-up table then this
2248 * is a repeated INIT packet, we need to remove this association from the
2249 * look-up table and add the new association
2251 * The new association is added to the head of the list and state is updated
2253 * @param la Pointer to the relevant libalias instance
2254 * @param assoc pointer to sctp association
2256 * @return SN_ADD_OK | SN_ADD_CLASH
2259 AddSctpAssocGlobal(struct libalias *la, struct sctp_nat_assoc *assoc)
2261 struct sctp_nat_assoc *found;
2263 LIBALIAS_LOCK_ASSERT(la);
2264 found = FindSctpGlobalClash(la, assoc);
2265 if (found != NULL) {
2266 if ((found->TableRegister == SN_GLOBAL_TBL) && \
2267 (found->l_addr.s_addr == assoc->l_addr.s_addr) && (found->l_port == assoc->l_port)) { /* resent message */
2268 RmSctpAssoc(la, found);
2269 sctp_RmTimeOut(la, found);
2270 freeGlobalAddressList(found);
2273 return(SN_ADD_CLASH);
2276 LIST_INSERT_HEAD(&la->sctpTableGlobal[SN_TABLE_HASH(assoc->g_vtag, assoc->g_port, la->sctpNatTableSize)],
2278 assoc->TableRegister |= SN_GLOBAL_TBL;
2279 la->sctpLinkCount++; //increment link count
2281 if (assoc->TableRegister == SN_BOTH_TBL) {
2282 /* libalias log -- controlled by libalias */
2283 if (la->packetAliasMode & PKT_ALIAS_LOG)
2284 SctpShowAliasStats(la);
2286 SN_LOG(SN_LOG_INFO, logsctpassoc(assoc, "^"));
2293 * @brief Remove the sctp association information from the look up table
2295 * For each of the two (local/global) look-up tables, remove the association
2296 * from that table IF it has been registered in that table.
2298 * NOTE: The calling code is responsible for freeing memory allocated to the
2299 * association structure itself
2301 * NOTE: The association is NOT removed from the timer queue
2303 * @param la Pointer to the relevant libalias instance
2304 * @param assoc pointer to sctp association
2307 RmSctpAssoc(struct libalias *la, struct sctp_nat_assoc *assoc)
2309 // struct sctp_nat_assoc *found;
2310 if (assoc == NULL) {
2311 /* very bad, log and die*/
2313 logsctperror("ERROR: alias_sctp:RmSctpAssoc(NULL)\n", 0, 0, SN_TO_NODIR));
2316 /* log if association is fully up and now closing */
2317 if (assoc->TableRegister == SN_BOTH_TBL) {
2318 SN_LOG(SN_LOG_INFO, logsctpassoc(assoc, "$"));
2320 LIBALIAS_LOCK_ASSERT(la);
2321 if (assoc->TableRegister & SN_LOCAL_TBL) {
2322 assoc->TableRegister ^= SN_LOCAL_TBL;
2323 la->sctpLinkCount--; //decrement link count
2324 LIST_REMOVE(assoc, list_L);
2327 if (assoc->TableRegister & SN_GLOBAL_TBL) {
2328 assoc->TableRegister ^= SN_GLOBAL_TBL;
2329 la->sctpLinkCount--; //decrement link count
2330 LIST_REMOVE(assoc, list_G);
2332 // sn_free(assoc); //Don't remove now, remove if needed later
2333 /* libalias logging -- controlled by libalias log definition */
2334 if (la->packetAliasMode & PKT_ALIAS_LOG)
2335 SctpShowAliasStats(la);
2340 * @brief free the Global Address List memory
2342 * freeGlobalAddressList deletes all global IP addresses in an associations
2343 * global IP address list.
2347 static void freeGlobalAddressList(struct sctp_nat_assoc *assoc)
2349 struct sctp_GlobalAddress *gaddr1=NULL,*gaddr2=NULL;
2350 /*free global address list*/
2351 gaddr1 = LIST_FIRST(&(assoc->Gaddr));
2352 while (gaddr1 != NULL) {
2353 gaddr2 = LIST_NEXT(gaddr1, list_Gaddr);
2358 /* ----------------------------------------------------------------------
2360 * ----------------------------------------------------------------------
2362 /** @addtogroup Timer
2364 * The timer queue management functions are designed to operate efficiently with
2365 * a minimum of interaction with the queues.
2367 * Once a timeout is set in the queue it will not be altered in the queue unless
2368 * it has to be changed to a shorter time (usually only for aborts and closing).
2369 * On a queue timeout, the real expiry time is checked, and if not leq than the
2370 * timeout it is requeued (O(1)) at its later time. This is especially important
2371 * for normal packets sent during an association. When a timer expires, it is
2372 * updated to its new expiration time if necessary, or processed as a
2373 * timeout. This means that while in UP state, the timing queue is only altered
2374 * every U_T (every few minutes) for a particular association.
2377 * @brief Add an association timeout to the timer queue
2379 * Determine the location in the queue to add the timeout and insert the
2380 * association into the list at that queue position
2386 sctp_AddTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc)
2389 LIBALIAS_LOCK_ASSERT(la);
2390 add_loc = assoc->exp - la->sctpNatTimer.loc_time + la->sctpNatTimer.cur_loc;
2391 if (add_loc >= SN_TIMER_QUEUE_SIZE)
2392 add_loc -= SN_TIMER_QUEUE_SIZE;
2393 LIST_INSERT_HEAD(&la->sctpNatTimer.TimerQ[add_loc], assoc, timer_Q);
2394 assoc->exp_loc = add_loc;
2398 * @brief Remove an association from timer queue
2400 * This is an O(1) operation to remove the association pointer from its
2401 * current position in the timer queue
2403 * @param la Pointer to the relevant libalias instance
2404 * @param assoc pointer to sctp association
2407 sctp_RmTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc)
2409 LIBALIAS_LOCK_ASSERT(la);
2410 LIST_REMOVE(assoc, timer_Q);/* Note this is O(1) */
2415 * @brief Reset timer in timer queue
2417 * Reset the actual timeout for the specified association. If it is earlier than
2418 * the existing timeout, then remove and re-install the association into the
2421 * @param la Pointer to the relevant libalias instance
2422 * @param assoc pointer to sctp association
2423 * @param newexp New expiration time
2426 sctp_ResetTimeOut(struct libalias *la, struct sctp_nat_assoc *assoc, int newexp)
2428 if (newexp < assoc->exp) {
2429 sctp_RmTimeOut(la, assoc);
2430 assoc->exp = newexp;
2431 sctp_AddTimeOut(la, assoc);
2433 assoc->exp = newexp;
2438 * @brief Check timer Q against current time
2440 * Loop through each entry in the timer queue since the last time we processed
2441 * the timer queue until now (the current time). For each association in the
2442 * event list, we remove it from that position in the timer queue and check if
2443 * it has really expired. If so we:
2444 * - Log the timer expiry
2445 * - Remove the association from the NAT tables
2446 * - Release the memory used by the association
2448 * If the timer hasn't really expired we place the association into its new
2449 * correct position in the timer queue.
2451 * @param la Pointer to the relevant libalias instance
2454 sctp_CheckTimers(struct libalias *la)
2456 struct sctp_nat_assoc *assoc;
2458 LIBALIAS_LOCK_ASSERT(la);
2459 while(la->timeStamp >= la->sctpNatTimer.loc_time) {
2460 while (!LIST_EMPTY(&la->sctpNatTimer.TimerQ[la->sctpNatTimer.cur_loc])) {
2461 assoc = LIST_FIRST(&la->sctpNatTimer.TimerQ[la->sctpNatTimer.cur_loc]);
2462 //SLIST_REMOVE_HEAD(&la->sctpNatTimer.TimerQ[la->sctpNatTimer.cur_loc], timer_Q);
2463 LIST_REMOVE(assoc, timer_Q);
2464 if (la->timeStamp >= assoc->exp) { /* state expired */
2465 SN_LOG(((assoc->state == SN_CL)?(SN_LOG_DEBUG):(SN_LOG_INFO)),
2466 logsctperror("Timer Expired", assoc->g_vtag, assoc->state, SN_TO_NODIR));
2467 RmSctpAssoc(la, assoc);
2468 freeGlobalAddressList(assoc);
2470 } else {/* state not expired, reschedule timer*/
2471 sctp_AddTimeOut(la, assoc);
2474 /* Goto next location in the timer queue*/
2475 ++la->sctpNatTimer.loc_time;
2476 if (++la->sctpNatTimer.cur_loc >= SN_TIMER_QUEUE_SIZE)
2477 la->sctpNatTimer.cur_loc = 0;
2481 /* ----------------------------------------------------------------------
2483 * ----------------------------------------------------------------------
2485 /** @addtogroup Logging
2487 * The logging functions provide logging of different items ranging from logging
2488 * a simple message, through logging an association details to logging the
2489 * current state of the NAT tables
2491 /** @ingroup Logging
2492 * @brief Log sctp nat errors
2494 * @param errormsg Error message to be logged
2495 * @param vtag Current Vtag
2496 * @param error Error number
2497 * @param direction Direction of packet
2500 logsctperror(char* errormsg, uint32_t vtag, int error, int direction)
2514 SctpAliasLog("->%c %s (vt=%u) %d\n", dir, errormsg, ntohl(vtag), error);
2517 /** @ingroup Logging
2518 * @brief Log what the parser parsed
2520 * @param direction Direction of packet
2521 * @param sm Pointer to sctp message information
2524 logsctpparse(int direction, struct sctp_nat_msg *sm)
2526 char *ploc, *pstate;
2529 ploc = "TO_LOCAL -";
2532 ploc = "TO_GLOBAL -";
2541 case SN_SCTP_INITACK:
2547 case SN_SCTP_SHUTACK:
2550 case SN_SCTP_SHUTCOMP:
2551 pstate = "ShutComp";
2553 case SN_SCTP_ASCONF:
2556 case SN_SCTP_ASCONFACK:
2557 pstate = "AsconfAck";
2563 pstate = "***ERROR***";
2566 SctpAliasLog("Parsed: %s %s\n", ploc, pstate);
2569 /** @ingroup Logging
2570 * @brief Log an SCTP association's details
2572 * @param assoc pointer to sctp association
2573 * @param s Character that indicates the state of processing for this packet
2575 static void logsctpassoc(struct sctp_nat_assoc *assoc, char* s)
2577 struct sctp_GlobalAddress *G_Addr = NULL;
2579 char addrbuf[INET_ADDRSTRLEN];
2581 switch(assoc->state) {
2604 SctpAliasLog("%sAssoc: %s exp=%u la=%s lv=%u lp=%u gv=%u gp=%u tbl=%d\n",
2605 s, sp, assoc->exp, inet_ntoa_r(assoc->l_addr, addrbuf),
2606 ntohl(assoc->l_vtag), ntohs(assoc->l_port),
2607 ntohl(assoc->g_vtag), ntohs(assoc->g_port),
2608 assoc->TableRegister);
2609 /* list global addresses */
2610 LIST_FOREACH(G_Addr, &(assoc->Gaddr), list_Gaddr) {
2611 SctpAliasLog("\t\tga=%s\n",
2612 inet_ntoa_r(G_Addr->g_addr, addrbuf));
2616 /** @ingroup Logging
2617 * @brief Output Global table to log
2619 * @param la Pointer to the relevant libalias instance
2621 static void logSctpGlobal(struct libalias *la)
2624 struct sctp_nat_assoc *assoc = NULL;
2626 SctpAliasLog("G->\n");
2627 for (i=0; i < la->sctpNatTableSize; i++) {
2628 LIST_FOREACH(assoc, &la->sctpTableGlobal[i], list_G) {
2629 logsctpassoc(assoc, " ");
2634 /** @ingroup Logging
2635 * @brief Output Local table to log
2637 * @param la Pointer to the relevant libalias instance
2639 static void logSctpLocal(struct libalias *la)
2642 struct sctp_nat_assoc *assoc = NULL;
2644 SctpAliasLog("L->\n");
2645 for (i=0; i < la->sctpNatTableSize; i++) {
2646 LIST_FOREACH(assoc, &la->sctpTableLocal[i], list_L) {
2647 logsctpassoc(assoc, " ");
2652 /** @ingroup Logging
2653 * @brief Output timer queue to log
2655 * @param la Pointer to the relevant libalias instance
2657 static void logTimerQ(struct libalias *la)
2659 static char buf[50];
2661 struct sctp_nat_assoc *assoc = NULL;
2663 SctpAliasLog("t->\n");
2664 for (i=0; i < SN_TIMER_QUEUE_SIZE; i++) {
2665 LIST_FOREACH(assoc, &la->sctpNatTimer.TimerQ[i], timer_Q) {
2666 snprintf(buf, 50, " l=%u ",i);
2667 //SctpAliasLog(la->logDesc," l=%d ",i);
2668 logsctpassoc(assoc, buf);
2673 /** @ingroup Logging
2674 * @brief Sctp NAT logging function
2676 * This function is based on a similar function in alias_db.c
2678 * @param str/stream logging descriptor
2679 * @param format printf type string
2683 SctpAliasLog(const char *format, ...)
2685 char buffer[LIBALIAS_BUF_SIZE];
2687 va_start(ap, format);
2688 vsnprintf(buffer, LIBALIAS_BUF_SIZE, format, ap);
2690 log(LOG_SECURITY | LOG_INFO,
2691 "alias_sctp: %s", buffer);
2695 SctpAliasLog(FILE *stream, const char *format, ...)
2699 va_start(ap, format);
2700 vfprintf(stream, format, ap);