1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* SCTP kernel implementation
3  * (C) Copyright IBM Corp. 2001, 2004
4  * Copyright (c) 1999-2000 Cisco, Inc.
5  * Copyright (c) 1999-2001 Motorola, Inc.
6  * Copyright (c) 2001 Intel Corp.
7  *
8  * This file is part of the SCTP kernel implementation
9  *
10  * Please send any bug reports or fixes you make to the
11  * email address(es):
12  *    lksctp developers <linux-sctp@vger.kernel.org>
13  *
14  * Written or modified by:
15  *   La Monte H.P. Yarroll <piggy@acm.org>
16  *   Karl Knutson          <karl@athena.chicago.il.us>
17  *   Randall Stewart       <randall@stewart.chicago.il.us>
18  *   Ken Morneau           <kmorneau@cisco.com>
19  *   Qiaobing Xie          <qxie1@motorola.com>
20  *   Xingang Guo           <xingang.guo@intel.com>
21  *   Sridhar Samudrala     <samudrala@us.ibm.com>
22  *   Daisy Chang           <daisyc@us.ibm.com>
23  */
24 
25 #ifndef __sctp_constants_h__
26 #define __sctp_constants_h__
27 
28 #include <linux/sctp.h>
29 #include <linux/ipv6.h> /* For ipv6hdr. */
30 #include <net/tcp_states.h>  /* For TCP states used in enum sctp_sock_state */
31 
32 /* Value used for stream negotiation. */
33 enum { SCTP_MAX_STREAM = 0xffff };
34 enum { SCTP_DEFAULT_OUTSTREAMS = 10 };
35 enum { SCTP_DEFAULT_INSTREAMS = SCTP_MAX_STREAM };
36 
37 /* Since CIDs are sparse, we need all four of the following
38  * symbols.  CIDs are dense through SCTP_CID_BASE_MAX.
39  */
40 #define SCTP_CID_BASE_MAX		SCTP_CID_SHUTDOWN_COMPLETE
41 
42 #define SCTP_NUM_BASE_CHUNK_TYPES	(SCTP_CID_BASE_MAX + 1)
43 
44 #define SCTP_NUM_ADDIP_CHUNK_TYPES	2
45 
46 #define SCTP_NUM_PRSCTP_CHUNK_TYPES	1
47 
48 #define SCTP_NUM_RECONF_CHUNK_TYPES	1
49 
50 #define SCTP_NUM_AUTH_CHUNK_TYPES	1
51 
52 #define SCTP_NUM_CHUNK_TYPES		(SCTP_NUM_BASE_CHUNK_TYPES + \
53 					 SCTP_NUM_ADDIP_CHUNK_TYPES +\
54 					 SCTP_NUM_PRSCTP_CHUNK_TYPES +\
55 					 SCTP_NUM_RECONF_CHUNK_TYPES +\
56 					 SCTP_NUM_AUTH_CHUNK_TYPES)
57 
58 /* These are the different flavours of event.  */
59 enum sctp_event_type {
60 	SCTP_EVENT_T_CHUNK = 1,
61 	SCTP_EVENT_T_TIMEOUT,
62 	SCTP_EVENT_T_OTHER,
63 	SCTP_EVENT_T_PRIMITIVE
64 };
65 
66 /* As a convenience for the state machine, we append SCTP_EVENT_* and
67  * SCTP_ULP_* to the list of possible chunks.
68  */
69 
70 enum sctp_event_timeout {
71 	SCTP_EVENT_TIMEOUT_NONE = 0,
72 	SCTP_EVENT_TIMEOUT_T1_COOKIE,
73 	SCTP_EVENT_TIMEOUT_T1_INIT,
74 	SCTP_EVENT_TIMEOUT_T2_SHUTDOWN,
75 	SCTP_EVENT_TIMEOUT_T3_RTX,
76 	SCTP_EVENT_TIMEOUT_T4_RTO,
77 	SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD,
78 	SCTP_EVENT_TIMEOUT_HEARTBEAT,
79 	SCTP_EVENT_TIMEOUT_RECONF,
80 	SCTP_EVENT_TIMEOUT_PROBE,
81 	SCTP_EVENT_TIMEOUT_SACK,
82 	SCTP_EVENT_TIMEOUT_AUTOCLOSE,
83 };
84 
85 #define SCTP_EVENT_TIMEOUT_MAX		SCTP_EVENT_TIMEOUT_AUTOCLOSE
86 #define SCTP_NUM_TIMEOUT_TYPES		(SCTP_EVENT_TIMEOUT_MAX + 1)
87 
88 enum sctp_event_other {
89 	SCTP_EVENT_NO_PENDING_TSN = 0,
90 	SCTP_EVENT_ICMP_PROTO_UNREACH,
91 };
92 
93 #define SCTP_EVENT_OTHER_MAX		SCTP_EVENT_ICMP_PROTO_UNREACH
94 #define SCTP_NUM_OTHER_TYPES		(SCTP_EVENT_OTHER_MAX + 1)
95 
96 /* These are primitive requests from the ULP.  */
97 enum sctp_event_primitive {
98 	SCTP_PRIMITIVE_ASSOCIATE = 0,
99 	SCTP_PRIMITIVE_SHUTDOWN,
100 	SCTP_PRIMITIVE_ABORT,
101 	SCTP_PRIMITIVE_SEND,
102 	SCTP_PRIMITIVE_REQUESTHEARTBEAT,
103 	SCTP_PRIMITIVE_ASCONF,
104 	SCTP_PRIMITIVE_RECONF,
105 };
106 
107 #define SCTP_EVENT_PRIMITIVE_MAX	SCTP_PRIMITIVE_RECONF
108 #define SCTP_NUM_PRIMITIVE_TYPES	(SCTP_EVENT_PRIMITIVE_MAX + 1)
109 
110 /* We define here a utility type for manipulating subtypes.
111  * The subtype constructors all work like this:
112  *
113  *   union sctp_subtype foo = SCTP_ST_CHUNK(SCTP_CID_INIT);
114  */
115 
116 union sctp_subtype {
117 	enum sctp_cid chunk;
118 	enum sctp_event_timeout timeout;
119 	enum sctp_event_other other;
120 	enum sctp_event_primitive primitive;
121 };
122 
123 #define SCTP_SUBTYPE_CONSTRUCTOR(_name, _type, _elt) \
124 static inline union sctp_subtype	\
125 SCTP_ST_## _name (_type _arg)		\
126 { union sctp_subtype _retval; _retval._elt = _arg; return _retval; }
127 
128 SCTP_SUBTYPE_CONSTRUCTOR(CHUNK,		enum sctp_cid,		chunk)
129 SCTP_SUBTYPE_CONSTRUCTOR(TIMEOUT,	enum sctp_event_timeout, timeout)
130 SCTP_SUBTYPE_CONSTRUCTOR(OTHER,		enum sctp_event_other,	other)
131 SCTP_SUBTYPE_CONSTRUCTOR(PRIMITIVE,	enum sctp_event_primitive, primitive)
132 
133 
134 #define sctp_chunk_is_data(a) (a->chunk_hdr->type == SCTP_CID_DATA || \
135 			       a->chunk_hdr->type == SCTP_CID_I_DATA)
136 
137 /* Internal error codes */
138 enum sctp_ierror {
139 	SCTP_IERROR_NO_ERROR	        = 0,
140 	SCTP_IERROR_BASE		= 1000,
141 	SCTP_IERROR_NO_COOKIE,
142 	SCTP_IERROR_BAD_SIG,
143 	SCTP_IERROR_STALE_COOKIE,
144 	SCTP_IERROR_NOMEM,
145 	SCTP_IERROR_MALFORMED,
146 	SCTP_IERROR_BAD_TAG,
147 	SCTP_IERROR_BIG_GAP,
148 	SCTP_IERROR_DUP_TSN,
149 	SCTP_IERROR_HIGH_TSN,
150 	SCTP_IERROR_IGNORE_TSN,
151 	SCTP_IERROR_NO_DATA,
152 	SCTP_IERROR_BAD_STREAM,
153 	SCTP_IERROR_BAD_PORTS,
154 	SCTP_IERROR_AUTH_BAD_HMAC,
155 	SCTP_IERROR_AUTH_BAD_KEYID,
156 	SCTP_IERROR_PROTO_VIOLATION,
157 	SCTP_IERROR_ERROR,
158 	SCTP_IERROR_ABORT,
159 };
160 
161 
162 
163 /* SCTP state defines for internal state machine */
164 enum sctp_state {
165 
166 	SCTP_STATE_CLOSED		= 0,
167 	SCTP_STATE_COOKIE_WAIT		= 1,
168 	SCTP_STATE_COOKIE_ECHOED	= 2,
169 	SCTP_STATE_ESTABLISHED		= 3,
170 	SCTP_STATE_SHUTDOWN_PENDING	= 4,
171 	SCTP_STATE_SHUTDOWN_SENT	= 5,
172 	SCTP_STATE_SHUTDOWN_RECEIVED	= 6,
173 	SCTP_STATE_SHUTDOWN_ACK_SENT	= 7,
174 
175 };
176 
177 #define SCTP_STATE_MAX			SCTP_STATE_SHUTDOWN_ACK_SENT
178 #define SCTP_STATE_NUM_STATES		(SCTP_STATE_MAX + 1)
179 
180 /* These are values for sk->state.
181  * For a UDP-style SCTP socket, the states are defined as follows
182  * - A socket in SCTP_SS_CLOSED state indicates that it is not willing to
183  *   accept new associations, but it can initiate the creation of new ones.
184  * - A socket in SCTP_SS_LISTENING state indicates that it is willing to
185  *   accept new  associations and can initiate the creation of new ones.
186  * - A socket in SCTP_SS_ESTABLISHED state indicates that it is a peeled off
187  *   socket with one association.
188  * For a TCP-style SCTP socket, the states are defined as follows
189  * - A socket in SCTP_SS_CLOSED state indicates that it is not willing to
190  *   accept new associations, but it can initiate the creation of new ones.
191  * - A socket in SCTP_SS_LISTENING state indicates that it is willing to
192  *   accept new associations, but cannot initiate the creation of new ones.
193  * - A socket in SCTP_SS_ESTABLISHED state indicates that it has a single
194  *   association.
195  */
196 enum sctp_sock_state {
197 	SCTP_SS_CLOSED         = TCP_CLOSE,
198 	SCTP_SS_LISTENING      = TCP_LISTEN,
199 	SCTP_SS_ESTABLISHING   = TCP_SYN_SENT,
200 	SCTP_SS_ESTABLISHED    = TCP_ESTABLISHED,
201 	SCTP_SS_CLOSING        = TCP_CLOSE_WAIT,
202 };
203 
204 enum sctp_plpmtud_state {
205 	SCTP_PL_DISABLED,
206 	SCTP_PL_BASE,
207 	SCTP_PL_SEARCH,
208 	SCTP_PL_COMPLETE,
209 	SCTP_PL_ERROR,
210 };
211 
212 #define	SCTP_BASE_PLPMTU	1200
213 #define	SCTP_MAX_PLPMTU		9000
214 #define	SCTP_MIN_PLPMTU		512
215 
216 #define	SCTP_MAX_PROBES		3
217 
218 #define SCTP_PL_BIG_STEP	32
219 #define SCTP_PL_MIN_STEP	4
220 
221 /* These functions map various type to printable names.  */
222 const char *sctp_cname(const union sctp_subtype id);	/* chunk types */
223 const char *sctp_oname(const union sctp_subtype id);	/* other events */
224 const char *sctp_tname(const union sctp_subtype id);	/* timeouts */
225 const char *sctp_pname(const union sctp_subtype id);	/* primitives */
226 
227 /* This is a table of printable names of sctp_state_t's.  */
228 extern const char *const sctp_state_tbl[];
229 extern const char *const sctp_evttype_tbl[];
230 extern const char *const sctp_status_tbl[];
231 
232 /* Maximum chunk length considering padding requirements. */
233 enum { SCTP_MAX_CHUNK_LEN = ((1<<16) - sizeof(__u32)) };
234 
235 /* Encourage Cookie-Echo bundling by pre-fragmenting chunks a little
236  * harder (until reaching ESTABLISHED state).
237  */
238 enum { SCTP_ARBITRARY_COOKIE_ECHO_LEN = 200 };
239 
240 /* Guess at how big to make the TSN mapping array.
241  * We guarantee that we can handle at least this big a gap between the
242  * cumulative ACK and the highest TSN.  In practice, we can often
243  * handle up to twice this value.
244  *
245  * NEVER make this more than 32767 (2^15-1).  The Gap Ack Blocks in a
246  * SACK (see  section 3.3.4) are only 16 bits, so 2*SCTP_TSN_MAP_SIZE
247  * must be less than 65535 (2^16 - 1), or we will have overflow
248  * problems creating SACK's.
249  */
250 #define SCTP_TSN_MAP_INITIAL BITS_PER_LONG
251 #define SCTP_TSN_MAP_INCREMENT SCTP_TSN_MAP_INITIAL
252 #define SCTP_TSN_MAP_SIZE 4096
253 
254 /* We will not record more than this many duplicate TSNs between two
255  * SACKs.  The minimum PMTU is 512.  Remove all the headers and there
256  * is enough room for 117 duplicate reports.  Round down to the
257  * nearest power of 2.
258  */
259 enum { SCTP_MAX_DUP_TSNS = 16 };
260 enum { SCTP_MAX_GABS = 16 };
261 
262 /* Heartbeat interval - 30 secs */
263 #define SCTP_DEFAULT_TIMEOUT_HEARTBEAT	(30*1000)
264 
265 /* Delayed sack timer - 200ms */
266 #define SCTP_DEFAULT_TIMEOUT_SACK	(200)
267 
268 /* RTO.Initial              - 3  seconds
269  * RTO.Min                  - 1  second
270  * RTO.Max                  - 60 seconds
271  * RTO.Alpha                - 1/8
272  * RTO.Beta                 - 1/4
273  */
274 #define SCTP_RTO_INITIAL	(3 * 1000)
275 #define SCTP_RTO_MIN		(1 * 1000)
276 #define SCTP_RTO_MAX		(60 * 1000)
277 
278 #define SCTP_RTO_ALPHA          3   /* 1/8 when converted to right shifts. */
279 #define SCTP_RTO_BETA           2   /* 1/4 when converted to right shifts. */
280 
281 /* Maximum number of new data packets that can be sent in a burst.  */
282 #define SCTP_DEFAULT_MAX_BURST		4
283 
284 #define SCTP_CLOCK_GRANULARITY	1	/* 1 jiffy */
285 
286 #define SCTP_DEFAULT_COOKIE_LIFE	(60 * 1000) /* 60 seconds */
287 
288 #define SCTP_DEFAULT_MINWINDOW	1500	/* default minimum rwnd size */
289 #define SCTP_DEFAULT_MAXWINDOW	65535	/* default rwnd size */
290 #define SCTP_DEFAULT_RWND_SHIFT  4	/* by default, update on 1/16 of
291 					 * rcvbuf, which is 1/8 of initial
292 					 * window
293 					 */
294 #define SCTP_DEFAULT_MAXSEGMENT 1500	/* MTU size, this is the limit
295                                          * to which we will raise the P-MTU.
296 					 */
297 #define SCTP_DEFAULT_MINSEGMENT 512	/* MTU size ... if no mtu disc */
298 
299 #define SCTP_SECRET_SIZE 32		/* Number of octets in a 256 bits. */
300 
301 #define SCTP_SIGNATURE_SIZE 20	        /* size of a SLA-1 signature */
302 
303 #define SCTP_COOKIE_MULTIPLE 32 /* Pad out our cookie to make our hash
304 				 * functions simpler to write.
305 				 */
306 
307 #define SCTP_DEFAULT_UDP_PORT 9899	/* default UDP tunneling port */
308 
309 /* These are the values for pf exposure, UNUSED is to keep compatible with old
310  * applications by default.
311  */
312 enum {
313 	SCTP_PF_EXPOSE_UNSET,
314 	SCTP_PF_EXPOSE_DISABLE,
315 	SCTP_PF_EXPOSE_ENABLE,
316 };
317 #define SCTP_PF_EXPOSE_MAX	SCTP_PF_EXPOSE_ENABLE
318 
319 #define SCTP_PS_RETRANS_MAX	0xffff
320 
321 /* These return values describe the success or failure of a number of
322  * routines which form the lower interface to SCTP_outqueue.
323  */
324 enum sctp_xmit {
325 	SCTP_XMIT_OK,
326 	SCTP_XMIT_PMTU_FULL,
327 	SCTP_XMIT_RWND_FULL,
328 	SCTP_XMIT_DELAY,
329 };
330 
331 /* These are the commands for manipulating transports.  */
332 enum sctp_transport_cmd {
333 	SCTP_TRANSPORT_UP,
334 	SCTP_TRANSPORT_DOWN,
335 	SCTP_TRANSPORT_PF,
336 };
337 
338 /* These are the address scopes defined mainly for IPv4 addresses
339  * based on draft of SCTP IPv4 scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
340  * These scopes are hopefully generic enough to be used on scoping both
341  * IPv4 and IPv6 addresses in SCTP.
342  * At this point, the IPv6 scopes will be mapped to these internal scopes
343  * as much as possible.
344  */
345 enum sctp_scope {
346 	SCTP_SCOPE_GLOBAL,		/* IPv4 global addresses */
347 	SCTP_SCOPE_PRIVATE,		/* IPv4 private addresses */
348 	SCTP_SCOPE_LINK,		/* IPv4 link local address */
349 	SCTP_SCOPE_LOOPBACK,		/* IPv4 loopback address */
350 	SCTP_SCOPE_UNUSABLE,		/* IPv4 unusable addresses */
351 };
352 
353 enum {
354 	SCTP_SCOPE_POLICY_DISABLE,	/* Disable IPv4 address scoping */
355 	SCTP_SCOPE_POLICY_ENABLE,	/* Enable IPv4 address scoping */
356 	SCTP_SCOPE_POLICY_PRIVATE,	/* Follow draft but allow IPv4 private addresses */
357 	SCTP_SCOPE_POLICY_LINK,		/* Follow draft but allow IPv4 link local addresses */
358 };
359 
360 #define SCTP_SCOPE_POLICY_MAX	SCTP_SCOPE_POLICY_LINK
361 
362 /* Based on IPv4 scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>,
363  * SCTP IPv4 unusable addresses: 0.0.0.0/8, 224.0.0.0/4, 192.88.99.0/24.
364  * Also, RFC 8.4, non-unicast addresses are not considered valid SCTP
365  * addresses.
366  */
367 #define IS_IPV4_UNUSABLE_ADDRESS(a)	    \
368 	((htonl(INADDR_BROADCAST) == a) ||  \
369 	 ipv4_is_multicast(a) ||	    \
370 	 ipv4_is_zeronet(a) ||		    \
371 	 ipv4_is_anycast_6to4(a))
372 
373 /* Flags used for the bind address copy functions.  */
374 #define SCTP_ADDR4_ALLOWED	0x00000001	/* IPv4 address is allowed by
375 						   local sock family */
376 #define SCTP_ADDR6_ALLOWED	0x00000002	/* IPv6 address is allowed by
377 						   local sock family */
378 #define SCTP_ADDR4_PEERSUPP	0x00000004	/* IPv4 address is supported by
379 						   peer */
380 #define SCTP_ADDR6_PEERSUPP	0x00000008	/* IPv6 address is supported by
381 						   peer */
382 
383 /* Reasons to retransmit. */
384 enum sctp_retransmit_reason {
385 	SCTP_RTXR_T3_RTX,
386 	SCTP_RTXR_FAST_RTX,
387 	SCTP_RTXR_PMTUD,
388 	SCTP_RTXR_T1_RTX,
389 };
390 
391 /* Reasons to lower cwnd. */
392 enum sctp_lower_cwnd {
393 	SCTP_LOWER_CWND_T3_RTX,
394 	SCTP_LOWER_CWND_FAST_RTX,
395 	SCTP_LOWER_CWND_ECNE,
396 	SCTP_LOWER_CWND_INACTIVE,
397 };
398 
399 
400 /* SCTP-AUTH Necessary constants */
401 
402 /* SCTP-AUTH, Section 3.3
403  *
404  *  The following Table 2 shows the currently defined values for HMAC
405  *  identifiers.
406  *
407  *  +-----------------+--------------------------+
408  *  | HMAC Identifier | Message Digest Algorithm |
409  *  +-----------------+--------------------------+
410  *  | 0               | Reserved                 |
411  *  | 1               | SHA-1 defined in [8]     |
412  *  | 2               | Reserved                 |
413  *  | 3               | SHA-256 defined in [8]   |
414  *  +-----------------+--------------------------+
415  */
416 enum {
417 	SCTP_AUTH_HMAC_ID_RESERVED_0,
418 	SCTP_AUTH_HMAC_ID_SHA1,
419 	SCTP_AUTH_HMAC_ID_RESERVED_2,
420 #if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
421 	SCTP_AUTH_HMAC_ID_SHA256,
422 #endif
423 	__SCTP_AUTH_HMAC_MAX
424 };
425 
426 #define SCTP_AUTH_HMAC_ID_MAX	__SCTP_AUTH_HMAC_MAX - 1
427 #define SCTP_AUTH_NUM_HMACS 	__SCTP_AUTH_HMAC_MAX
428 #define SCTP_SHA1_SIG_SIZE 20
429 #define SCTP_SHA256_SIG_SIZE 32
430 
431 /*  SCTP-AUTH, Section 3.2
432  *     The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH chunks
433  *     MUST NOT be listed in the CHUNKS parameter
434  */
435 #define SCTP_NUM_NOAUTH_CHUNKS	4
436 #define SCTP_AUTH_MAX_CHUNKS	(SCTP_NUM_CHUNK_TYPES - SCTP_NUM_NOAUTH_CHUNKS)
437 
438 /* SCTP-AUTH Section 6.1
439  * The RANDOM parameter MUST contain a 32 byte random number.
440  */
441 #define SCTP_AUTH_RANDOM_LENGTH 32
442 
443 #define SCTP_PROBE_TIMER_MIN	5000
444 
445 #endif /* __sctp_constants_h__ */
446