1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001 Intel Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * This SCTP implementation is free software;
10  * you can redistribute it and/or modify it under the terms of
11  * the GNU General Public License as published by
12  * the Free Software Foundation; either version 2, or (at your option)
13  * any later version.
14  *
15  * This SCTP implementation is distributed in the hope that it
16  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
17  *                 ************************
18  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19  * See the GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with GNU CC; see the file COPYING.  If not, see
23  * <http://www.gnu.org/licenses/>.
24  *
25  * Please send any bug reports or fixes you make to the
26  * email address(es):
27  *    lksctp developers <linux-sctp@vger.kernel.org>
28  *
29  * Written or modified by:
30  *   La Monte H.P. Yarroll <piggy@acm.org>
31  *   Karl Knutson          <karl@athena.chicago.il.us>
32  *   Randall Stewart       <randall@stewart.chicago.il.us>
33  *   Ken Morneau           <kmorneau@cisco.com>
34  *   Qiaobing Xie          <qxie1@motorola.com>
35  *   Xingang Guo           <xingang.guo@intel.com>
36  *   Sridhar Samudrala     <samudrala@us.ibm.com>
37  *   Daisy Chang           <daisyc@us.ibm.com>
38  */
39 
40 #ifndef __sctp_constants_h__
41 #define __sctp_constants_h__
42 
43 #include <linux/sctp.h>
44 #include <linux/ipv6.h> /* For ipv6hdr. */
45 #include <net/tcp_states.h>  /* For TCP states used in enum sctp_sock_state */
46 
47 /* Value used for stream negotiation. */
48 enum { SCTP_MAX_STREAM = 0xffff };
49 enum { SCTP_DEFAULT_OUTSTREAMS = 10 };
50 enum { SCTP_DEFAULT_INSTREAMS = SCTP_MAX_STREAM };
51 
52 /* Since CIDs are sparse, we need all four of the following
53  * symbols.  CIDs are dense through SCTP_CID_BASE_MAX.
54  */
55 #define SCTP_CID_BASE_MAX		SCTP_CID_SHUTDOWN_COMPLETE
56 
57 #define SCTP_NUM_BASE_CHUNK_TYPES	(SCTP_CID_BASE_MAX + 1)
58 
59 #define SCTP_NUM_ADDIP_CHUNK_TYPES	2
60 
61 #define SCTP_NUM_PRSCTP_CHUNK_TYPES	1
62 
63 #define SCTP_NUM_RECONF_CHUNK_TYPES	1
64 
65 #define SCTP_NUM_AUTH_CHUNK_TYPES	1
66 
67 #define SCTP_NUM_CHUNK_TYPES		(SCTP_NUM_BASE_CHUNK_TYPES + \
68 					 SCTP_NUM_ADDIP_CHUNK_TYPES +\
69 					 SCTP_NUM_PRSCTP_CHUNK_TYPES +\
70 					 SCTP_NUM_RECONF_CHUNK_TYPES +\
71 					 SCTP_NUM_AUTH_CHUNK_TYPES)
72 
73 /* These are the different flavours of event.  */
74 enum sctp_event {
75 	SCTP_EVENT_T_CHUNK = 1,
76 	SCTP_EVENT_T_TIMEOUT,
77 	SCTP_EVENT_T_OTHER,
78 	SCTP_EVENT_T_PRIMITIVE
79 };
80 
81 /* As a convenience for the state machine, we append SCTP_EVENT_* and
82  * SCTP_ULP_* to the list of possible chunks.
83  */
84 
85 enum sctp_event_timeout {
86 	SCTP_EVENT_TIMEOUT_NONE = 0,
87 	SCTP_EVENT_TIMEOUT_T1_COOKIE,
88 	SCTP_EVENT_TIMEOUT_T1_INIT,
89 	SCTP_EVENT_TIMEOUT_T2_SHUTDOWN,
90 	SCTP_EVENT_TIMEOUT_T3_RTX,
91 	SCTP_EVENT_TIMEOUT_T4_RTO,
92 	SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD,
93 	SCTP_EVENT_TIMEOUT_HEARTBEAT,
94 	SCTP_EVENT_TIMEOUT_RECONF,
95 	SCTP_EVENT_TIMEOUT_SACK,
96 	SCTP_EVENT_TIMEOUT_AUTOCLOSE,
97 };
98 
99 #define SCTP_EVENT_TIMEOUT_MAX		SCTP_EVENT_TIMEOUT_AUTOCLOSE
100 #define SCTP_NUM_TIMEOUT_TYPES		(SCTP_EVENT_TIMEOUT_MAX + 1)
101 
102 enum sctp_event_other {
103 	SCTP_EVENT_NO_PENDING_TSN = 0,
104 	SCTP_EVENT_ICMP_PROTO_UNREACH,
105 };
106 
107 #define SCTP_EVENT_OTHER_MAX		SCTP_EVENT_ICMP_PROTO_UNREACH
108 #define SCTP_NUM_OTHER_TYPES		(SCTP_EVENT_OTHER_MAX + 1)
109 
110 /* These are primitive requests from the ULP.  */
111 enum sctp_event_primitive {
112 	SCTP_PRIMITIVE_ASSOCIATE = 0,
113 	SCTP_PRIMITIVE_SHUTDOWN,
114 	SCTP_PRIMITIVE_ABORT,
115 	SCTP_PRIMITIVE_SEND,
116 	SCTP_PRIMITIVE_REQUESTHEARTBEAT,
117 	SCTP_PRIMITIVE_ASCONF,
118 	SCTP_PRIMITIVE_RECONF,
119 };
120 
121 #define SCTP_EVENT_PRIMITIVE_MAX	SCTP_PRIMITIVE_RECONF
122 #define SCTP_NUM_PRIMITIVE_TYPES	(SCTP_EVENT_PRIMITIVE_MAX + 1)
123 
124 /* We define here a utility type for manipulating subtypes.
125  * The subtype constructors all work like this:
126  *
127  *   union sctp_subtype foo = SCTP_ST_CHUNK(SCTP_CID_INIT);
128  */
129 
130 union sctp_subtype {
131 	enum sctp_cid chunk;
132 	enum sctp_event_timeout timeout;
133 	enum sctp_event_other other;
134 	enum sctp_event_primitive primitive;
135 };
136 
137 #define SCTP_SUBTYPE_CONSTRUCTOR(_name, _type, _elt) \
138 static inline union sctp_subtype	\
139 SCTP_ST_## _name (_type _arg)		\
140 { union sctp_subtype _retval; _retval._elt = _arg; return _retval; }
141 
142 SCTP_SUBTYPE_CONSTRUCTOR(CHUNK,		enum sctp_cid,		chunk)
143 SCTP_SUBTYPE_CONSTRUCTOR(TIMEOUT,	enum sctp_event_timeout, timeout)
144 SCTP_SUBTYPE_CONSTRUCTOR(OTHER,		enum sctp_event_other,	other)
145 SCTP_SUBTYPE_CONSTRUCTOR(PRIMITIVE,	enum sctp_event_primitive, primitive)
146 
147 
148 #define sctp_chunk_is_data(a) (a->chunk_hdr->type == SCTP_CID_DATA || \
149 			       a->chunk_hdr->type == SCTP_CID_I_DATA)
150 
151 /* Calculate the actual data size in a data chunk */
152 #define SCTP_DATA_SNDSIZE(c) ((int)((unsigned long)(c->chunk_end) - \
153 				    (unsigned long)(c->chunk_hdr) - \
154 				    sctp_datachk_len(&c->asoc->stream)))
155 
156 /* Internal error codes */
157 enum sctp_ierror {
158 	SCTP_IERROR_NO_ERROR	        = 0,
159 	SCTP_IERROR_BASE		= 1000,
160 	SCTP_IERROR_NO_COOKIE,
161 	SCTP_IERROR_BAD_SIG,
162 	SCTP_IERROR_STALE_COOKIE,
163 	SCTP_IERROR_NOMEM,
164 	SCTP_IERROR_MALFORMED,
165 	SCTP_IERROR_BAD_TAG,
166 	SCTP_IERROR_BIG_GAP,
167 	SCTP_IERROR_DUP_TSN,
168 	SCTP_IERROR_HIGH_TSN,
169 	SCTP_IERROR_IGNORE_TSN,
170 	SCTP_IERROR_NO_DATA,
171 	SCTP_IERROR_BAD_STREAM,
172 	SCTP_IERROR_BAD_PORTS,
173 	SCTP_IERROR_AUTH_BAD_HMAC,
174 	SCTP_IERROR_AUTH_BAD_KEYID,
175 	SCTP_IERROR_PROTO_VIOLATION,
176 	SCTP_IERROR_ERROR,
177 	SCTP_IERROR_ABORT,
178 };
179 
180 
181 
182 /* SCTP state defines for internal state machine */
183 enum sctp_state {
184 
185 	SCTP_STATE_CLOSED		= 0,
186 	SCTP_STATE_COOKIE_WAIT		= 1,
187 	SCTP_STATE_COOKIE_ECHOED	= 2,
188 	SCTP_STATE_ESTABLISHED		= 3,
189 	SCTP_STATE_SHUTDOWN_PENDING	= 4,
190 	SCTP_STATE_SHUTDOWN_SENT	= 5,
191 	SCTP_STATE_SHUTDOWN_RECEIVED	= 6,
192 	SCTP_STATE_SHUTDOWN_ACK_SENT	= 7,
193 
194 };
195 
196 #define SCTP_STATE_MAX			SCTP_STATE_SHUTDOWN_ACK_SENT
197 #define SCTP_STATE_NUM_STATES		(SCTP_STATE_MAX + 1)
198 
199 /* These are values for sk->state.
200  * For a UDP-style SCTP socket, the states are defined as follows
201  * - A socket in SCTP_SS_CLOSED state indicates that it is not willing to
202  *   accept new associations, but it can initiate the creation of new ones.
203  * - A socket in SCTP_SS_LISTENING state indicates that it is willing to
204  *   accept new  associations and can initiate the creation of new ones.
205  * - A socket in SCTP_SS_ESTABLISHED state indicates that it is a peeled off
206  *   socket with one association.
207  * For a TCP-style SCTP socket, the states are defined as follows
208  * - A socket in SCTP_SS_CLOSED state indicates that it is not willing to
209  *   accept new associations, but it can initiate the creation of new ones.
210  * - A socket in SCTP_SS_LISTENING state indicates that it is willing to
211  *   accept new associations, but cannot initiate the creation of new ones.
212  * - A socket in SCTP_SS_ESTABLISHED state indicates that it has a single
213  *   association.
214  */
215 enum sctp_sock_state {
216 	SCTP_SS_CLOSED         = TCP_CLOSE,
217 	SCTP_SS_LISTENING      = TCP_LISTEN,
218 	SCTP_SS_ESTABLISHING   = TCP_SYN_SENT,
219 	SCTP_SS_ESTABLISHED    = TCP_ESTABLISHED,
220 	SCTP_SS_CLOSING        = TCP_CLOSE_WAIT,
221 };
222 
223 /* These functions map various type to printable names.  */
224 const char *sctp_cname(const union sctp_subtype id);	/* chunk types */
225 const char *sctp_oname(const union sctp_subtype id);	/* other events */
226 const char *sctp_tname(const union sctp_subtype id);	/* timeouts */
227 const char *sctp_pname(const union sctp_subtype id);	/* primitives */
228 
229 /* This is a table of printable names of sctp_state_t's.  */
230 extern const char *const sctp_state_tbl[];
231 extern const char *const sctp_evttype_tbl[];
232 extern const char *const sctp_status_tbl[];
233 
234 /* Maximum chunk length considering padding requirements. */
235 enum { SCTP_MAX_CHUNK_LEN = ((1<<16) - sizeof(__u32)) };
236 
237 /* Encourage Cookie-Echo bundling by pre-fragmenting chunks a little
238  * harder (until reaching ESTABLISHED state).
239  */
240 enum { SCTP_ARBITRARY_COOKIE_ECHO_LEN = 200 };
241 
242 /* Guess at how big to make the TSN mapping array.
243  * We guarantee that we can handle at least this big a gap between the
244  * cumulative ACK and the highest TSN.  In practice, we can often
245  * handle up to twice this value.
246  *
247  * NEVER make this more than 32767 (2^15-1).  The Gap Ack Blocks in a
248  * SACK (see  section 3.3.4) are only 16 bits, so 2*SCTP_TSN_MAP_SIZE
249  * must be less than 65535 (2^16 - 1), or we will have overflow
250  * problems creating SACK's.
251  */
252 #define SCTP_TSN_MAP_INITIAL BITS_PER_LONG
253 #define SCTP_TSN_MAP_INCREMENT SCTP_TSN_MAP_INITIAL
254 #define SCTP_TSN_MAP_SIZE 4096
255 
256 /* We will not record more than this many duplicate TSNs between two
257  * SACKs.  The minimum PMTU is 512.  Remove all the headers and there
258  * is enough room for 117 duplicate reports.  Round down to the
259  * nearest power of 2.
260  */
261 enum { SCTP_MAX_DUP_TSNS = 16 };
262 enum { SCTP_MAX_GABS = 16 };
263 
264 /* Heartbeat interval - 30 secs */
265 #define SCTP_DEFAULT_TIMEOUT_HEARTBEAT	(30*1000)
266 
267 /* Delayed sack timer - 200ms */
268 #define SCTP_DEFAULT_TIMEOUT_SACK	(200)
269 
270 /* RTO.Initial              - 3  seconds
271  * RTO.Min                  - 1  second
272  * RTO.Max                  - 60 seconds
273  * RTO.Alpha                - 1/8
274  * RTO.Beta                 - 1/4
275  */
276 #define SCTP_RTO_INITIAL	(3 * 1000)
277 #define SCTP_RTO_MIN		(1 * 1000)
278 #define SCTP_RTO_MAX		(60 * 1000)
279 
280 #define SCTP_RTO_ALPHA          3   /* 1/8 when converted to right shifts. */
281 #define SCTP_RTO_BETA           2   /* 1/4 when converted to right shifts. */
282 
283 /* Maximum number of new data packets that can be sent in a burst.  */
284 #define SCTP_DEFAULT_MAX_BURST		4
285 
286 #define SCTP_CLOCK_GRANULARITY	1	/* 1 jiffy */
287 
288 #define SCTP_DEFAULT_COOKIE_LIFE	(60 * 1000) /* 60 seconds */
289 
290 #define SCTP_DEFAULT_MINWINDOW	1500	/* default minimum rwnd size */
291 #define SCTP_DEFAULT_MAXWINDOW	65535	/* default rwnd size */
292 #define SCTP_DEFAULT_RWND_SHIFT  4	/* by default, update on 1/16 of
293 					 * rcvbuf, which is 1/8 of initial
294 					 * window
295 					 */
296 #define SCTP_DEFAULT_MAXSEGMENT 1500	/* MTU size, this is the limit
297                                          * to which we will raise the P-MTU.
298 					 */
299 #define SCTP_DEFAULT_MINSEGMENT 512	/* MTU size ... if no mtu disc */
300 
301 #define SCTP_SECRET_SIZE 32		/* Number of octets in a 256 bits. */
302 
303 #define SCTP_SIGNATURE_SIZE 20	        /* size of a SLA-1 signature */
304 
305 #define SCTP_COOKIE_MULTIPLE 32 /* Pad out our cookie to make our hash
306 				 * functions simpler to write.
307 				 */
308 
309 /* These return values describe the success or failure of a number of
310  * routines which form the lower interface to SCTP_outqueue.
311  */
312 enum sctp_xmit {
313 	SCTP_XMIT_OK,
314 	SCTP_XMIT_PMTU_FULL,
315 	SCTP_XMIT_RWND_FULL,
316 	SCTP_XMIT_DELAY,
317 };
318 
319 /* These are the commands for manipulating transports.  */
320 enum sctp_transport_cmd {
321 	SCTP_TRANSPORT_UP,
322 	SCTP_TRANSPORT_DOWN,
323 	SCTP_TRANSPORT_PF,
324 };
325 
326 /* These are the address scopes defined mainly for IPv4 addresses
327  * based on draft of SCTP IPv4 scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
328  * These scopes are hopefully generic enough to be used on scoping both
329  * IPv4 and IPv6 addresses in SCTP.
330  * At this point, the IPv6 scopes will be mapped to these internal scopes
331  * as much as possible.
332  */
333 enum sctp_scope {
334 	SCTP_SCOPE_GLOBAL,		/* IPv4 global addresses */
335 	SCTP_SCOPE_PRIVATE,		/* IPv4 private addresses */
336 	SCTP_SCOPE_LINK,		/* IPv4 link local address */
337 	SCTP_SCOPE_LOOPBACK,		/* IPv4 loopback address */
338 	SCTP_SCOPE_UNUSABLE,		/* IPv4 unusable addresses */
339 };
340 
341 enum {
342 	SCTP_SCOPE_POLICY_DISABLE,	/* Disable IPv4 address scoping */
343 	SCTP_SCOPE_POLICY_ENABLE,	/* Enable IPv4 address scoping */
344 	SCTP_SCOPE_POLICY_PRIVATE,	/* Follow draft but allow IPv4 private addresses */
345 	SCTP_SCOPE_POLICY_LINK,		/* Follow draft but allow IPv4 link local addresses */
346 };
347 
348 #define SCTP_SCOPE_POLICY_MAX	SCTP_SCOPE_POLICY_LINK
349 
350 /* Based on IPv4 scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>,
351  * SCTP IPv4 unusable addresses: 0.0.0.0/8, 224.0.0.0/4, 198.18.0.0/24,
352  * 192.88.99.0/24.
353  * Also, RFC 8.4, non-unicast addresses are not considered valid SCTP
354  * addresses.
355  */
356 #define IS_IPV4_UNUSABLE_ADDRESS(a)	    \
357 	((htonl(INADDR_BROADCAST) == a) ||  \
358 	 ipv4_is_multicast(a) ||	    \
359 	 ipv4_is_zeronet(a) ||		    \
360 	 ipv4_is_test_198(a) ||		    \
361 	 ipv4_is_anycast_6to4(a))
362 
363 /* Flags used for the bind address copy functions.  */
364 #define SCTP_ADDR6_ALLOWED	0x00000001	/* IPv6 address is allowed by
365 						   local sock family */
366 #define SCTP_ADDR4_PEERSUPP	0x00000002	/* IPv4 address is supported by
367 						   peer */
368 #define SCTP_ADDR6_PEERSUPP	0x00000004	/* IPv6 address is supported by
369 						   peer */
370 
371 /* Reasons to retransmit. */
372 enum sctp_retransmit_reason {
373 	SCTP_RTXR_T3_RTX,
374 	SCTP_RTXR_FAST_RTX,
375 	SCTP_RTXR_PMTUD,
376 	SCTP_RTXR_T1_RTX,
377 };
378 
379 /* Reasons to lower cwnd. */
380 enum sctp_lower_cwnd {
381 	SCTP_LOWER_CWND_T3_RTX,
382 	SCTP_LOWER_CWND_FAST_RTX,
383 	SCTP_LOWER_CWND_ECNE,
384 	SCTP_LOWER_CWND_INACTIVE,
385 };
386 
387 
388 /* SCTP-AUTH Necessary constants */
389 
390 /* SCTP-AUTH, Section 3.3
391  *
392  *  The following Table 2 shows the currently defined values for HMAC
393  *  identifiers.
394  *
395  *  +-----------------+--------------------------+
396  *  | HMAC Identifier | Message Digest Algorithm |
397  *  +-----------------+--------------------------+
398  *  | 0               | Reserved                 |
399  *  | 1               | SHA-1 defined in [8]     |
400  *  | 2               | Reserved                 |
401  *  | 3               | SHA-256 defined in [8]   |
402  *  +-----------------+--------------------------+
403  */
404 enum {
405 	SCTP_AUTH_HMAC_ID_RESERVED_0,
406 	SCTP_AUTH_HMAC_ID_SHA1,
407 	SCTP_AUTH_HMAC_ID_RESERVED_2,
408 #if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
409 	SCTP_AUTH_HMAC_ID_SHA256,
410 #endif
411 	__SCTP_AUTH_HMAC_MAX
412 };
413 
414 #define SCTP_AUTH_HMAC_ID_MAX	__SCTP_AUTH_HMAC_MAX - 1
415 #define SCTP_AUTH_NUM_HMACS 	__SCTP_AUTH_HMAC_MAX
416 #define SCTP_SHA1_SIG_SIZE 20
417 #define SCTP_SHA256_SIG_SIZE 32
418 
419 /*  SCTP-AUTH, Section 3.2
420  *     The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH chunks
421  *     MUST NOT be listed in the CHUNKS parameter
422  */
423 #define SCTP_NUM_NOAUTH_CHUNKS	4
424 #define SCTP_AUTH_MAX_CHUNKS	(SCTP_NUM_CHUNK_TYPES - SCTP_NUM_NOAUTH_CHUNKS)
425 
426 /* SCTP-AUTH Section 6.1
427  * The RANDOM parameter MUST contain a 32 byte random number.
428  */
429 #define SCTP_AUTH_RANDOM_LENGTH 32
430 
431 #endif /* __sctp_constants_h__ */
432