xref: /linux-6.15/include/linux/dccp.h (revision b454cc66)
1 #ifndef _LINUX_DCCP_H
2 #define _LINUX_DCCP_H
3 
4 #include <linux/types.h>
5 #include <asm/byteorder.h>
6 
7 /**
8  * struct dccp_hdr - generic part of DCCP packet header
9  *
10  * @dccph_sport - Relevant port on the endpoint that sent this packet
11  * @dccph_dport - Relevant port on the other endpoint
12  * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
13  * @dccph_ccval - Used by the HC-Sender CCID
14  * @dccph_cscov - Parts of the packet that are covered by the Checksum field
15  * @dccph_checksum - Internet checksum, depends on dccph_cscov
16  * @dccph_x - 0 = 24 bit sequence number, 1 = 48
17  * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
18  * @dccph_seq - sequence number high or low order 24 bits, depends on dccph_x
19  */
20 struct dccp_hdr {
21 	__be16	dccph_sport,
22 		dccph_dport;
23 	__u8	dccph_doff;
24 #if defined(__LITTLE_ENDIAN_BITFIELD)
25 	__u8	dccph_cscov:4,
26 		dccph_ccval:4;
27 #elif defined(__BIG_ENDIAN_BITFIELD)
28 	__u8	dccph_ccval:4,
29 		dccph_cscov:4;
30 #else
31 #error  "Adjust your <asm/byteorder.h> defines"
32 #endif
33 	__sum16	dccph_checksum;
34 #if defined(__LITTLE_ENDIAN_BITFIELD)
35 	__u8	dccph_x:1,
36 		dccph_type:4,
37 		dccph_reserved:3;
38 #elif defined(__BIG_ENDIAN_BITFIELD)
39 	__u8	dccph_reserved:3,
40 		dccph_type:4,
41 		dccph_x:1;
42 #else
43 #error  "Adjust your <asm/byteorder.h> defines"
44 #endif
45 	__u8	dccph_seq2;
46 	__be16	dccph_seq;
47 };
48 
49 /**
50  * struct dccp_hdr_ext - the low bits of a 48 bit seq packet
51  *
52  * @dccph_seq_low - low 24 bits of a 48 bit seq packet
53  */
54 struct dccp_hdr_ext {
55 	__be32	dccph_seq_low;
56 };
57 
58 /**
59  * struct dccp_hdr_request - Conection initiation request header
60  *
61  * @dccph_req_service - Service to which the client app wants to connect
62  * @dccph_req_options - list of options (must be a multiple of 32 bits
63  */
64 struct dccp_hdr_request {
65 	__be32	dccph_req_service;
66 };
67 /**
68  * struct dccp_hdr_ack_bits - acknowledgment bits common to most packets
69  *
70  * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
71  * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
72  */
73 struct dccp_hdr_ack_bits {
74 	__be16	dccph_reserved1;
75 	__be16	dccph_ack_nr_high;
76 	__be32	dccph_ack_nr_low;
77 };
78 /**
79  * struct dccp_hdr_response - Conection initiation response header
80  *
81  * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
82  * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
83  * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
84  * @dccph_resp_options - list of options (must be a multiple of 32 bits
85  */
86 struct dccp_hdr_response {
87 	struct dccp_hdr_ack_bits	dccph_resp_ack;
88 	__be32				dccph_resp_service;
89 };
90 
91 /**
92  * struct dccp_hdr_reset - Unconditionally shut down a connection
93  *
94  * @dccph_reset_service - Echoes the Service Code on a received DCCP-Request
95  * @dccph_reset_options - list of options (must be a multiple of 32 bits
96  */
97 struct dccp_hdr_reset {
98 	struct dccp_hdr_ack_bits	dccph_reset_ack;
99 	__u8				dccph_reset_code,
100 					dccph_reset_data[3];
101 };
102 
103 enum dccp_pkt_type {
104 	DCCP_PKT_REQUEST = 0,
105 	DCCP_PKT_RESPONSE,
106 	DCCP_PKT_DATA,
107 	DCCP_PKT_ACK,
108 	DCCP_PKT_DATAACK,
109 	DCCP_PKT_CLOSEREQ,
110 	DCCP_PKT_CLOSE,
111 	DCCP_PKT_RESET,
112 	DCCP_PKT_SYNC,
113 	DCCP_PKT_SYNCACK,
114 	DCCP_PKT_INVALID,
115 };
116 
117 #define DCCP_NR_PKT_TYPES DCCP_PKT_INVALID
118 
119 static inline unsigned int dccp_packet_hdr_len(const __u8 type)
120 {
121 	if (type == DCCP_PKT_DATA)
122 		return 0;
123 	if (type == DCCP_PKT_DATAACK	||
124 	    type == DCCP_PKT_ACK	||
125 	    type == DCCP_PKT_SYNC	||
126 	    type == DCCP_PKT_SYNCACK	||
127 	    type == DCCP_PKT_CLOSE	||
128 	    type == DCCP_PKT_CLOSEREQ)
129 		return sizeof(struct dccp_hdr_ack_bits);
130 	if (type == DCCP_PKT_REQUEST)
131 		return sizeof(struct dccp_hdr_request);
132 	if (type == DCCP_PKT_RESPONSE)
133 		return sizeof(struct dccp_hdr_response);
134 	return sizeof(struct dccp_hdr_reset);
135 }
136 enum dccp_reset_codes {
137 	DCCP_RESET_CODE_UNSPECIFIED = 0,
138 	DCCP_RESET_CODE_CLOSED,
139 	DCCP_RESET_CODE_ABORTED,
140 	DCCP_RESET_CODE_NO_CONNECTION,
141 	DCCP_RESET_CODE_PACKET_ERROR,
142 	DCCP_RESET_CODE_OPTION_ERROR,
143 	DCCP_RESET_CODE_MANDATORY_ERROR,
144 	DCCP_RESET_CODE_CONNECTION_REFUSED,
145 	DCCP_RESET_CODE_BAD_SERVICE_CODE,
146 	DCCP_RESET_CODE_TOO_BUSY,
147 	DCCP_RESET_CODE_BAD_INIT_COOKIE,
148 	DCCP_RESET_CODE_AGGRESSION_PENALTY,
149 };
150 
151 /* DCCP options */
152 enum {
153 	DCCPO_PADDING = 0,
154 	DCCPO_MANDATORY = 1,
155 	DCCPO_MIN_RESERVED = 3,
156 	DCCPO_MAX_RESERVED = 31,
157 	DCCPO_CHANGE_L = 32,
158 	DCCPO_CONFIRM_L = 33,
159 	DCCPO_CHANGE_R = 34,
160 	DCCPO_CONFIRM_R = 35,
161 	DCCPO_NDP_COUNT = 37,
162 	DCCPO_ACK_VECTOR_0 = 38,
163 	DCCPO_ACK_VECTOR_1 = 39,
164 	DCCPO_TIMESTAMP = 41,
165 	DCCPO_TIMESTAMP_ECHO = 42,
166 	DCCPO_ELAPSED_TIME = 43,
167 	DCCPO_MAX = 45,
168 	DCCPO_MIN_CCID_SPECIFIC = 128,
169 	DCCPO_MAX_CCID_SPECIFIC = 255,
170 };
171 
172 /* DCCP CCIDS */
173 enum {
174 	DCCPC_CCID2 = 2,
175 	DCCPC_CCID3 = 3,
176 };
177 
178 /* DCCP features (RFC 4340 section 6.4) */
179 enum {
180 	DCCPF_RESERVED = 0,
181 	DCCPF_CCID = 1,
182 	DCCPF_SHORT_SEQNOS = 2,		/* XXX: not yet implemented */
183 	DCCPF_SEQUENCE_WINDOW = 3,
184 	DCCPF_ECN_INCAPABLE = 4,	/* XXX: not yet implemented */
185 	DCCPF_ACK_RATIO = 5,
186 	DCCPF_SEND_ACK_VECTOR = 6,
187 	DCCPF_SEND_NDP_COUNT = 7,
188 	DCCPF_MIN_CSUM_COVER = 8,
189 	DCCPF_DATA_CHECKSUM = 9,	/* XXX: not yet implemented */
190 	/* 10-127 reserved */
191 	DCCPF_MIN_CCID_SPECIFIC = 128,
192 	DCCPF_MAX_CCID_SPECIFIC = 255,
193 };
194 
195 /* this structure is argument to DCCP_SOCKOPT_CHANGE_X */
196 struct dccp_so_feat {
197 	__u8 dccpsf_feat;
198 	__u8 __user *dccpsf_val;
199 	__u8 dccpsf_len;
200 };
201 
202 /* DCCP socket options */
203 #define DCCP_SOCKOPT_PACKET_SIZE	1 /* XXX deprecated, without effect */
204 #define DCCP_SOCKOPT_SERVICE		2
205 #define DCCP_SOCKOPT_CHANGE_L		3
206 #define DCCP_SOCKOPT_CHANGE_R		4
207 #define DCCP_SOCKOPT_SEND_CSCOV		10
208 #define DCCP_SOCKOPT_RECV_CSCOV		11
209 #define DCCP_SOCKOPT_CCID_RX_INFO	128
210 #define DCCP_SOCKOPT_CCID_TX_INFO	192
211 
212 /* maximum number of services provided on the same listening port */
213 #define DCCP_SERVICE_LIST_MAX_LEN      32
214 
215 #ifdef __KERNEL__
216 
217 #include <linux/in.h>
218 #include <linux/list.h>
219 #include <linux/uio.h>
220 #include <linux/workqueue.h>
221 
222 #include <net/inet_connection_sock.h>
223 #include <net/inet_sock.h>
224 #include <net/inet_timewait_sock.h>
225 #include <net/tcp_states.h>
226 
227 enum dccp_state {
228 	DCCP_OPEN	= TCP_ESTABLISHED,
229 	DCCP_REQUESTING	= TCP_SYN_SENT,
230 	DCCP_PARTOPEN	= TCP_FIN_WAIT1, /* FIXME:
231 					    This mapping is horrible, but TCP has
232 					    no matching state for DCCP_PARTOPEN,
233 					    as TCP_SYN_RECV is already used by
234 					    DCCP_RESPOND, why don't stop using TCP
235 					    mapping of states? OK, now we don't use
236 					    sk_stream_sendmsg anymore, so doesn't
237 					    seem to exist any reason for us to
238 					    do the TCP mapping here */
239 	DCCP_LISTEN	= TCP_LISTEN,
240 	DCCP_RESPOND	= TCP_SYN_RECV,
241 	DCCP_CLOSING	= TCP_CLOSING,
242 	DCCP_TIME_WAIT	= TCP_TIME_WAIT,
243 	DCCP_CLOSED	= TCP_CLOSE,
244 	DCCP_MAX_STATES = TCP_MAX_STATES,
245 };
246 
247 #define DCCP_STATE_MASK 0xf
248 #define DCCP_ACTION_FIN (1<<7)
249 
250 enum {
251 	DCCPF_OPEN	 = TCPF_ESTABLISHED,
252 	DCCPF_REQUESTING = TCPF_SYN_SENT,
253 	DCCPF_PARTOPEN	 = TCPF_FIN_WAIT1,
254 	DCCPF_LISTEN	 = TCPF_LISTEN,
255 	DCCPF_RESPOND	 = TCPF_SYN_RECV,
256 	DCCPF_CLOSING	 = TCPF_CLOSING,
257 	DCCPF_TIME_WAIT	 = TCPF_TIME_WAIT,
258 	DCCPF_CLOSED	 = TCPF_CLOSE,
259 };
260 
261 static inline struct dccp_hdr *dccp_hdr(const struct sk_buff *skb)
262 {
263 	return (struct dccp_hdr *)skb->h.raw;
264 }
265 
266 static inline struct dccp_hdr *dccp_zeroed_hdr(struct sk_buff *skb, int headlen)
267 {
268 	skb->h.raw = skb_push(skb, headlen);
269 	memset(skb->h.raw, 0, headlen);
270 	return dccp_hdr(skb);
271 }
272 
273 static inline struct dccp_hdr_ext *dccp_hdrx(const struct sk_buff *skb)
274 {
275 	return (struct dccp_hdr_ext *)(skb->h.raw + sizeof(struct dccp_hdr));
276 }
277 
278 static inline unsigned int __dccp_basic_hdr_len(const struct dccp_hdr *dh)
279 {
280 	return sizeof(*dh) + (dh->dccph_x ? sizeof(struct dccp_hdr_ext) : 0);
281 }
282 
283 static inline unsigned int dccp_basic_hdr_len(const struct sk_buff *skb)
284 {
285 	const struct dccp_hdr *dh = dccp_hdr(skb);
286 	return __dccp_basic_hdr_len(dh);
287 }
288 
289 static inline __u64 dccp_hdr_seq(const struct sk_buff *skb)
290 {
291 	const struct dccp_hdr *dh = dccp_hdr(skb);
292 	__u64 seq_nr =  ntohs(dh->dccph_seq);
293 
294 	if (dh->dccph_x != 0)
295 		seq_nr = (seq_nr << 32) + ntohl(dccp_hdrx(skb)->dccph_seq_low);
296 	else
297 		seq_nr += (u32)dh->dccph_seq2 << 16;
298 
299 	return seq_nr;
300 }
301 
302 static inline struct dccp_hdr_request *dccp_hdr_request(struct sk_buff *skb)
303 {
304 	return (struct dccp_hdr_request *)(skb->h.raw + dccp_basic_hdr_len(skb));
305 }
306 
307 static inline struct dccp_hdr_ack_bits *dccp_hdr_ack_bits(const struct sk_buff *skb)
308 {
309 	return (struct dccp_hdr_ack_bits *)(skb->h.raw + dccp_basic_hdr_len(skb));
310 }
311 
312 static inline u64 dccp_hdr_ack_seq(const struct sk_buff *skb)
313 {
314 	const struct dccp_hdr_ack_bits *dhack = dccp_hdr_ack_bits(skb);
315 	return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) + ntohl(dhack->dccph_ack_nr_low);
316 }
317 
318 static inline struct dccp_hdr_response *dccp_hdr_response(struct sk_buff *skb)
319 {
320 	return (struct dccp_hdr_response *)(skb->h.raw + dccp_basic_hdr_len(skb));
321 }
322 
323 static inline struct dccp_hdr_reset *dccp_hdr_reset(struct sk_buff *skb)
324 {
325 	return (struct dccp_hdr_reset *)(skb->h.raw + dccp_basic_hdr_len(skb));
326 }
327 
328 static inline unsigned int __dccp_hdr_len(const struct dccp_hdr *dh)
329 {
330 	return __dccp_basic_hdr_len(dh) +
331 	       dccp_packet_hdr_len(dh->dccph_type);
332 }
333 
334 static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
335 {
336 	return __dccp_hdr_len(dccp_hdr(skb));
337 }
338 
339 
340 /* initial values for each feature */
341 #define DCCPF_INITIAL_SEQUENCE_WINDOW		100
342 #define DCCPF_INITIAL_ACK_RATIO			2
343 #define DCCPF_INITIAL_CCID			DCCPC_CCID2
344 #define DCCPF_INITIAL_SEND_ACK_VECTOR		1
345 /* FIXME: for now we're default to 1 but it should really be 0 */
346 #define DCCPF_INITIAL_SEND_NDP_COUNT		1
347 
348 #define DCCP_NDP_LIMIT 0xFFFFFF
349 
350 /**
351   * struct dccp_minisock - Minimal DCCP connection representation
352   *
353   * Will be used to pass the state from dccp_request_sock to dccp_sock.
354   *
355   * @dccpms_sequence_window - Sequence Window Feature (section 7.5.2)
356   * @dccpms_ccid - Congestion Control Id (CCID) (section 10)
357   * @dccpms_send_ack_vector - Send Ack Vector Feature (section 11.5)
358   * @dccpms_send_ndp_count - Send NDP Count Feature (7.7.2)
359   * @dccpms_ack_ratio - Ack Ratio Feature (section 11.3)
360   * @dccpms_pending - List of features being negotiated
361   * @dccpms_conf -
362   */
363 struct dccp_minisock {
364 	__u64			dccpms_sequence_window;
365 	__u8			dccpms_rx_ccid;
366 	__u8			dccpms_tx_ccid;
367 	__u8			dccpms_send_ack_vector;
368 	__u8			dccpms_send_ndp_count;
369 	__u8			dccpms_ack_ratio;
370 	struct list_head	dccpms_pending;
371 	struct list_head	dccpms_conf;
372 };
373 
374 struct dccp_opt_conf {
375 	__u8			*dccpoc_val;
376 	__u8			dccpoc_len;
377 };
378 
379 struct dccp_opt_pend {
380 	struct list_head	dccpop_node;
381 	__u8			dccpop_type;
382 	__u8			dccpop_feat;
383 	__u8		        *dccpop_val;
384 	__u8			dccpop_len;
385 	int			dccpop_conf;
386 	struct dccp_opt_conf    *dccpop_sc;
387 };
388 
389 extern void __dccp_minisock_init(struct dccp_minisock *dmsk);
390 extern void dccp_minisock_init(struct dccp_minisock *dmsk);
391 
392 extern int dccp_parse_options(struct sock *sk, struct sk_buff *skb);
393 
394 struct dccp_request_sock {
395 	struct inet_request_sock dreq_inet_rsk;
396 	__u64			 dreq_iss;
397 	__u64			 dreq_isr;
398 	__be32			 dreq_service;
399 };
400 
401 static inline struct dccp_request_sock *dccp_rsk(const struct request_sock *req)
402 {
403 	return (struct dccp_request_sock *)req;
404 }
405 
406 extern struct inet_timewait_death_row dccp_death_row;
407 
408 struct dccp_options_received {
409 	u32	dccpor_ndp; /* only 24 bits */
410 	u32	dccpor_timestamp;
411 	u32	dccpor_timestamp_echo;
412 	u32	dccpor_elapsed_time;
413 };
414 
415 struct ccid;
416 
417 enum dccp_role {
418 	DCCP_ROLE_UNDEFINED,
419 	DCCP_ROLE_LISTEN,
420 	DCCP_ROLE_CLIENT,
421 	DCCP_ROLE_SERVER,
422 };
423 
424 struct dccp_service_list {
425 	__u32	dccpsl_nr;
426 	__be32	dccpsl_list[0];
427 };
428 
429 #define DCCP_SERVICE_INVALID_VALUE htonl((__u32)-1)
430 #define DCCP_SERVICE_CODE_IS_ABSENT		0
431 
432 static inline int dccp_list_has_service(const struct dccp_service_list *sl,
433 					const __be32 service)
434 {
435 	if (likely(sl != NULL)) {
436 		u32 i = sl->dccpsl_nr;
437 		while (i--)
438 			if (sl->dccpsl_list[i] == service)
439 				return 1;
440 	}
441 	return 0;
442 }
443 
444 struct dccp_ackvec;
445 
446 /**
447  * struct dccp_sock - DCCP socket state
448  *
449  * @dccps_swl - sequence number window low
450  * @dccps_swh - sequence number window high
451  * @dccps_awl - acknowledgement number window low
452  * @dccps_awh - acknowledgement number window high
453  * @dccps_iss - initial sequence number sent
454  * @dccps_isr - initial sequence number received
455  * @dccps_osr - first OPEN sequence number received
456  * @dccps_gss - greatest sequence number sent
457  * @dccps_gsr - greatest valid sequence number received
458  * @dccps_gar - greatest valid ack number received on a non-Sync; initialized to %dccps_iss
459  * @dccps_service - first (passive sock) or unique (active sock) service code
460  * @dccps_service_list - second .. last service code on passive socket
461  * @dccps_timestamp_time - time of latest TIMESTAMP option
462  * @dccps_timestamp_echo - latest timestamp received on a TIMESTAMP option
463  * @dccps_l_ack_ratio -
464  * @dccps_r_ack_ratio -
465  * @dccps_pcslen - sender   partial checksum coverage (via sockopt)
466  * @dccps_pcrlen - receiver partial checksum coverage (via sockopt)
467  * @dccps_ndp_count - number of Non Data Packets since last data packet
468  * @dccps_mss_cache -
469  * @dccps_minisock -
470  * @dccps_hc_rx_ackvec - rx half connection ack vector
471  * @dccps_hc_rx_ccid -
472  * @dccps_hc_tx_ccid -
473  * @dccps_options_received -
474  * @dccps_epoch -
475  * @dccps_role - Role of this sock, one of %dccp_role
476  * @dccps_hc_rx_insert_options -
477  * @dccps_hc_tx_insert_options -
478  * @dccps_xmit_timer - timer for when CCID is not ready to send
479  */
480 struct dccp_sock {
481 	/* inet_connection_sock has to be the first member of dccp_sock */
482 	struct inet_connection_sock	dccps_inet_connection;
483 	__u64				dccps_swl;
484 	__u64				dccps_swh;
485 	__u64				dccps_awl;
486 	__u64				dccps_awh;
487 	__u64				dccps_iss;
488 	__u64				dccps_isr;
489 	__u64				dccps_osr;
490 	__u64				dccps_gss;
491 	__u64				dccps_gsr;
492 	__u64				dccps_gar;
493 	__be32				dccps_service;
494 	struct dccp_service_list	*dccps_service_list;
495 	struct timeval			dccps_timestamp_time;
496 	__u32				dccps_timestamp_echo;
497 	__u16				dccps_l_ack_ratio;
498 	__u16				dccps_r_ack_ratio;
499 	__u16				dccps_pcslen;
500 	__u16				dccps_pcrlen;
501 	unsigned long			dccps_ndp_count;
502 	__u32				dccps_mss_cache;
503 	struct dccp_minisock		dccps_minisock;
504 	struct dccp_ackvec		*dccps_hc_rx_ackvec;
505 	struct ccid			*dccps_hc_rx_ccid;
506 	struct ccid			*dccps_hc_tx_ccid;
507 	struct dccp_options_received	dccps_options_received;
508 	struct timeval			dccps_epoch;
509 	enum dccp_role			dccps_role:2;
510 	__u8				dccps_hc_rx_insert_options:1;
511 	__u8				dccps_hc_tx_insert_options:1;
512 	struct timer_list		dccps_xmit_timer;
513 };
514 
515 static inline struct dccp_sock *dccp_sk(const struct sock *sk)
516 {
517 	return (struct dccp_sock *)sk;
518 }
519 
520 static inline struct dccp_minisock *dccp_msk(const struct sock *sk)
521 {
522 	return (struct dccp_minisock *)&dccp_sk(sk)->dccps_minisock;
523 }
524 
525 static inline const char *dccp_role(const struct sock *sk)
526 {
527 	switch (dccp_sk(sk)->dccps_role) {
528 	case DCCP_ROLE_UNDEFINED: return "undefined";
529 	case DCCP_ROLE_LISTEN:	  return "listen";
530 	case DCCP_ROLE_SERVER:	  return "server";
531 	case DCCP_ROLE_CLIENT:	  return "client";
532 	}
533 	return NULL;
534 }
535 
536 #endif /* __KERNEL__ */
537 
538 #endif /* _LINUX_DCCP_H */
539