xref: /openbmc/linux/net/dccp/dccp.h (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 #ifndef _DCCP_H
2 #define _DCCP_H
3 /*
4  *  net/dccp/dccp.h
5  *
6  *  An implementation of the DCCP protocol
7  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
8  *  Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
9  *
10  *	This program is free software; you can redistribute it and/or modify it
11  *	under the terms of the GNU General Public License version 2 as
12  *	published by the Free Software Foundation.
13  */
14 
15 #include <linux/dccp.h>
16 #include <net/snmp.h>
17 #include <net/sock.h>
18 #include <net/tcp.h>
19 #include "ackvec.h"
20 
21 /*
22  * 	DCCP - specific warning and debugging macros.
23  */
24 #define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt,       \
25 							__FUNCTION__, ##a)
26 #define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \
27 					 __FILE__, __LINE__, __FUNCTION__)
28 #define DCCP_BUG(a...)       do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0)
29 #define DCCP_BUG_ON(cond)    do { if (unlikely((cond) != 0))		   \
30 				     DCCP_BUG("\"%s\" holds (exception!)", \
31 					      __stringify(cond));          \
32 			     } while (0)
33 
34 #define DCCP_PRINTK(enable, fmt, args...)	do { if (enable)	     \
35 							printk(fmt, ##args); \
36 						} while(0)
37 #define DCCP_PR_DEBUG(enable, fmt, a...)	DCCP_PRINTK(enable, KERN_DEBUG \
38 						  "%s: " fmt, __FUNCTION__, ##a)
39 
40 #ifdef CONFIG_IP_DCCP_DEBUG
41 extern int dccp_debug;
42 #define dccp_pr_debug(format, a...)	  DCCP_PR_DEBUG(dccp_debug, format, ##a)
43 #define dccp_pr_debug_cat(format, a...)   DCCP_PRINTK(dccp_debug, format, ##a)
44 #else
45 #define dccp_pr_debug(format, a...)
46 #define dccp_pr_debug_cat(format, a...)
47 #endif
48 
49 extern struct inet_hashinfo dccp_hashinfo;
50 
51 extern atomic_t dccp_orphan_count;
52 
53 extern void dccp_time_wait(struct sock *sk, int state, int timeo);
54 
55 /*
56  *  Set safe upper bounds for header and option length. Since Data Offset is 8
57  *  bits (RFC 4340, sec. 5.1), the total header length can never be more than
58  *  4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
59  *    - DCCP-Response with ACK Subheader and 4 bytes of Service code      OR
60  *    - DCCP-Reset    with ACK Subheader and 4 bytes of Reset Code fields
61  *  Hence a safe upper bound for the maximum option length is 1020-28 = 992
62  */
63 #define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int))
64 #define DCCP_MAX_PACKET_HDR 28
65 #define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
66 #define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
67 
68 #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
69 				     * state, about 60 seconds */
70 
71 /* RFC 1122, 4.2.3.1 initial RTO value */
72 #define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
73 
74 #define DCCP_RTO_MAX ((unsigned)(120 * HZ)) /* FIXME: using TCP value */
75 
76 /* bounds for sampled RTT values from packet exchanges (in usec) */
77 #define DCCP_SANE_RTT_MIN	100
78 #define DCCP_SANE_RTT_MAX	(4 * USEC_PER_SEC)
79 
80 /* Maximal interval between probes for local resources.  */
81 #define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
82 
83 /* sysctl variables for DCCP */
84 extern int  sysctl_dccp_request_retries;
85 extern int  sysctl_dccp_retries1;
86 extern int  sysctl_dccp_retries2;
87 extern int  sysctl_dccp_feat_sequence_window;
88 extern int  sysctl_dccp_feat_rx_ccid;
89 extern int  sysctl_dccp_feat_tx_ccid;
90 extern int  sysctl_dccp_feat_ack_ratio;
91 extern int  sysctl_dccp_feat_send_ack_vector;
92 extern int  sysctl_dccp_feat_send_ndp_count;
93 extern int  sysctl_dccp_tx_qlen;
94 
95 /*
96  *	48-bit sequence number arithmetic (signed and unsigned)
97  */
98 #define INT48_MIN	  0x800000000000LL		/* 2^47	    */
99 #define UINT48_MAX	  0xFFFFFFFFFFFFLL		/* 2^48 - 1 */
100 #define COMPLEMENT48(x)	 (0x1000000000000LL - (x))	/* 2^48 - x */
101 #define TO_SIGNED48(x)	 (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
102 #define TO_UNSIGNED48(x) (((x) >= 0)?	     (x) :  COMPLEMENT48(-(x)))
103 #define ADD48(a, b)	 (((a) + (b)) & UINT48_MAX)
104 #define SUB48(a, b)	 ADD48((a), COMPLEMENT48(b))
105 
106 static inline void dccp_set_seqno(u64 *seqno, u64 value)
107 {
108 	*seqno = value & UINT48_MAX;
109 }
110 
111 static inline void dccp_inc_seqno(u64 *seqno)
112 {
113 	*seqno = ADD48(*seqno, 1);
114 }
115 
116 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
117 static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
118 {
119 	u64 delta = SUB48(seqno2, seqno1);
120 
121 	return TO_SIGNED48(delta);
122 }
123 
124 /* is seq1 < seq2 ? */
125 static inline int before48(const u64 seq1, const u64 seq2)
126 {
127 	return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
128 }
129 
130 /* is seq1 > seq2 ? */
131 #define after48(seq1, seq2)	before48(seq2, seq1)
132 
133 /* is seq2 <= seq1 <= seq3 ? */
134 static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
135 {
136 	return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
137 }
138 
139 static inline u64 max48(const u64 seq1, const u64 seq2)
140 {
141 	return after48(seq1, seq2) ? seq1 : seq2;
142 }
143 
144 /* is seq1 next seqno after seq2 */
145 static inline int follows48(const u64 seq1, const u64 seq2)
146 {
147 	return dccp_delta_seqno(seq2, seq1) == 1;
148 }
149 
150 enum {
151 	DCCP_MIB_NUM = 0,
152 	DCCP_MIB_ACTIVEOPENS,			/* ActiveOpens */
153 	DCCP_MIB_ESTABRESETS,			/* EstabResets */
154 	DCCP_MIB_CURRESTAB,			/* CurrEstab */
155 	DCCP_MIB_OUTSEGS,			/* OutSegs */
156 	DCCP_MIB_OUTRSTS,
157 	DCCP_MIB_ABORTONTIMEOUT,
158 	DCCP_MIB_TIMEOUTS,
159 	DCCP_MIB_ABORTFAILED,
160 	DCCP_MIB_PASSIVEOPENS,
161 	DCCP_MIB_ATTEMPTFAILS,
162 	DCCP_MIB_OUTDATAGRAMS,
163 	DCCP_MIB_INERRS,
164 	DCCP_MIB_OPTMANDATORYERROR,
165 	DCCP_MIB_INVALIDOPT,
166 	__DCCP_MIB_MAX
167 };
168 
169 #define DCCP_MIB_MAX	__DCCP_MIB_MAX
170 struct dccp_mib {
171 	unsigned long	mibs[DCCP_MIB_MAX];
172 } __SNMP_MIB_ALIGN__;
173 
174 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
175 #define DCCP_INC_STATS(field)	    SNMP_INC_STATS(dccp_statistics, field)
176 #define DCCP_INC_STATS_BH(field)    SNMP_INC_STATS_BH(dccp_statistics, field)
177 #define DCCP_INC_STATS_USER(field)  SNMP_INC_STATS_USER(dccp_statistics, field)
178 #define DCCP_DEC_STATS(field)	    SNMP_DEC_STATS(dccp_statistics, field)
179 #define DCCP_ADD_STATS_BH(field, val) \
180 			SNMP_ADD_STATS_BH(dccp_statistics, field, val)
181 #define DCCP_ADD_STATS_USER(field, val)	\
182 			SNMP_ADD_STATS_USER(dccp_statistics, field, val)
183 
184 /*
185  * 	Checksumming routines
186  */
187 static inline int dccp_csum_coverage(const struct sk_buff *skb)
188 {
189 	const struct dccp_hdr* dh = dccp_hdr(skb);
190 
191 	if (dh->dccph_cscov == 0)
192 		return skb->len;
193 	return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
194 }
195 
196 static inline void dccp_csum_outgoing(struct sk_buff *skb)
197 {
198 	int cov = dccp_csum_coverage(skb);
199 
200 	if (cov >= skb->len)
201 		dccp_hdr(skb)->dccph_cscov = 0;
202 
203 	skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
204 }
205 
206 extern void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
207 
208 extern int  dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
209 
210 extern void dccp_send_ack(struct sock *sk);
211 extern void dccp_send_delayed_ack(struct sock *sk);
212 extern void dccp_reqsk_send_ack(struct sk_buff *sk, struct request_sock *rsk);
213 
214 extern void dccp_send_sync(struct sock *sk, const u64 seq,
215 			   const enum dccp_pkt_type pkt_type);
216 
217 extern void dccp_write_xmit(struct sock *sk, int block);
218 extern void dccp_write_space(struct sock *sk);
219 
220 extern void dccp_init_xmit_timers(struct sock *sk);
221 static inline void dccp_clear_xmit_timers(struct sock *sk)
222 {
223 	inet_csk_clear_xmit_timers(sk);
224 }
225 
226 extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
227 
228 extern const char *dccp_packet_name(const int type);
229 extern const char *dccp_state_name(const int state);
230 
231 extern void dccp_set_state(struct sock *sk, const int state);
232 extern void dccp_done(struct sock *sk);
233 
234 extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb);
235 
236 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
237 
238 extern struct sock *dccp_create_openreq_child(struct sock *sk,
239 					      const struct request_sock *req,
240 					      const struct sk_buff *skb);
241 
242 extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
243 
244 extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
245 					      struct sk_buff *skb,
246 					      struct request_sock *req,
247 					      struct dst_entry *dst);
248 extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
249 				   struct request_sock *req,
250 				   struct request_sock **prev);
251 
252 extern int dccp_child_process(struct sock *parent, struct sock *child,
253 			      struct sk_buff *skb);
254 extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
255 				  struct dccp_hdr *dh, unsigned len);
256 extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
257 				const struct dccp_hdr *dh, const unsigned len);
258 
259 extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
260 extern int dccp_destroy_sock(struct sock *sk);
261 
262 extern void		dccp_close(struct sock *sk, long timeout);
263 extern struct sk_buff	*dccp_make_response(struct sock *sk,
264 					    struct dst_entry *dst,
265 					    struct request_sock *req);
266 
267 extern int	   dccp_connect(struct sock *sk);
268 extern int	   dccp_disconnect(struct sock *sk, int flags);
269 extern void	   dccp_hash(struct sock *sk);
270 extern void	   dccp_unhash(struct sock *sk);
271 extern int	   dccp_getsockopt(struct sock *sk, int level, int optname,
272 				   char __user *optval, int __user *optlen);
273 extern int	   dccp_setsockopt(struct sock *sk, int level, int optname,
274 				   char __user *optval, int optlen);
275 #ifdef CONFIG_COMPAT
276 extern int	   compat_dccp_getsockopt(struct sock *sk,
277 				int level, int optname,
278 				char __user *optval, int __user *optlen);
279 extern int	   compat_dccp_setsockopt(struct sock *sk,
280 				int level, int optname,
281 				char __user *optval, int optlen);
282 #endif
283 extern int	   dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
284 extern int	   dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
285 				struct msghdr *msg, size_t size);
286 extern int	   dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
287 				struct msghdr *msg, size_t len, int nonblock,
288 				int flags, int *addr_len);
289 extern void	   dccp_shutdown(struct sock *sk, int how);
290 extern int	   inet_dccp_listen(struct socket *sock, int backlog);
291 extern unsigned int dccp_poll(struct file *file, struct socket *sock,
292 			     poll_table *wait);
293 extern int	   dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
294 				   int addr_len);
295 
296 extern int	   dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
297 extern void	   dccp_send_close(struct sock *sk, const int active);
298 extern int	   dccp_invalid_packet(struct sk_buff *skb);
299 extern u32	   dccp_sample_rtt(struct sock *sk, struct timeval *t_recv,
300 						    struct timeval *t_history);
301 
302 static inline int dccp_bad_service_code(const struct sock *sk,
303 					const __be32 service)
304 {
305 	const struct dccp_sock *dp = dccp_sk(sk);
306 
307 	if (dp->dccps_service == service)
308 		return 0;
309 	return !dccp_list_has_service(dp->dccps_service_list, service);
310 }
311 
312 struct dccp_skb_cb {
313 	__u8  dccpd_type:4;
314 	__u8  dccpd_ccval:4;
315 	__u8  dccpd_reset_code;
316 	__u16 dccpd_opt_len;
317 	__u64 dccpd_seq;
318 	__u64 dccpd_ack_seq;
319 };
320 
321 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
322 
323 static inline int dccp_non_data_packet(const struct sk_buff *skb)
324 {
325 	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
326 
327 	return type == DCCP_PKT_ACK	 ||
328 	       type == DCCP_PKT_CLOSE	 ||
329 	       type == DCCP_PKT_CLOSEREQ ||
330 	       type == DCCP_PKT_RESET	 ||
331 	       type == DCCP_PKT_SYNC	 ||
332 	       type == DCCP_PKT_SYNCACK;
333 }
334 
335 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
336 {
337 	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
338 
339 	return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
340 }
341 
342 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
343 
344 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
345 {
346 	struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
347 							   sizeof(*dh));
348 	dh->dccph_seq2 = 0;
349 	dh->dccph_seq = htons((gss >> 32) & 0xfffff);
350 	dhx->dccph_seq_low = htonl(gss & 0xffffffff);
351 }
352 
353 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
354 				    const u64 gsr)
355 {
356 	dhack->dccph_reserved1 = 0;
357 	dhack->dccph_ack_nr_high = htons(gsr >> 32);
358 	dhack->dccph_ack_nr_low  = htonl(gsr & 0xffffffff);
359 }
360 
361 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
362 {
363 	struct dccp_sock *dp = dccp_sk(sk);
364 	const struct dccp_minisock *dmsk = dccp_msk(sk);
365 
366 	dp->dccps_gsr = seq;
367 	dccp_set_seqno(&dp->dccps_swl,
368 		       dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
369 	dccp_set_seqno(&dp->dccps_swh,
370 		       dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
371 }
372 
373 static inline void dccp_update_gss(struct sock *sk, u64 seq)
374 {
375 	struct dccp_sock *dp = dccp_sk(sk);
376 
377 	dp->dccps_awh = dp->dccps_gss = seq;
378 	dccp_set_seqno(&dp->dccps_awl,
379 		       (dp->dccps_gss -
380 			dccp_msk(sk)->dccpms_sequence_window + 1));
381 }
382 
383 static inline int dccp_ack_pending(const struct sock *sk)
384 {
385 	const struct dccp_sock *dp = dccp_sk(sk);
386 	return dp->dccps_timestamp_echo != 0 ||
387 #ifdef CONFIG_IP_DCCP_ACKVEC
388 	       (dccp_msk(sk)->dccpms_send_ack_vector &&
389 		dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
390 #endif
391 	       inet_csk_ack_scheduled(sk);
392 }
393 
394 extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
395 extern int dccp_insert_option_elapsed_time(struct sock *sk,
396 					    struct sk_buff *skb,
397 					    u32 elapsed_time);
398 extern int dccp_insert_option_timestamp(struct sock *sk,
399 					 struct sk_buff *skb);
400 extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
401 			       unsigned char option,
402 			       const void *value, unsigned char len);
403 
404 extern void dccp_timestamp(const struct sock *sk, struct timeval *tv);
405 
406 static inline suseconds_t timeval_usecs(const struct timeval *tv)
407 {
408 	return tv->tv_sec * USEC_PER_SEC + tv->tv_usec;
409 }
410 
411 static inline suseconds_t timeval_delta(const struct timeval *large,
412 					const struct timeval *small)
413 {
414 	time_t	    secs  = large->tv_sec  - small->tv_sec;
415 	suseconds_t usecs = large->tv_usec - small->tv_usec;
416 
417 	if (usecs < 0) {
418 		secs--;
419 		usecs += USEC_PER_SEC;
420 	}
421 	return secs * USEC_PER_SEC + usecs;
422 }
423 
424 static inline void timeval_add_usecs(struct timeval *tv,
425 				     const suseconds_t usecs)
426 {
427 	tv->tv_usec += usecs;
428 	while (tv->tv_usec >= USEC_PER_SEC) {
429 		tv->tv_sec++;
430 		tv->tv_usec -= USEC_PER_SEC;
431 	}
432 }
433 
434 static inline void timeval_sub_usecs(struct timeval *tv,
435 				     const suseconds_t usecs)
436 {
437 	tv->tv_usec -= usecs;
438 	while (tv->tv_usec < 0) {
439 		tv->tv_sec--;
440 		tv->tv_usec += USEC_PER_SEC;
441 	}
442 	DCCP_BUG_ON(tv->tv_sec < 0);
443 }
444 
445 #ifdef CONFIG_SYSCTL
446 extern int dccp_sysctl_init(void);
447 extern void dccp_sysctl_exit(void);
448 #else
449 static inline int dccp_sysctl_init(void)
450 {
451 	return 0;
452 }
453 
454 static inline void dccp_sysctl_exit(void)
455 {
456 }
457 #endif
458 
459 #endif /* _DCCP_H */
460