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 <linux/ktime.h>
17 #include <net/snmp.h>
18 #include <net/sock.h>
19 #include <net/tcp.h>
20 #include "ackvec.h"
21 
22 /*
23  * 	DCCP - specific warning and debugging macros.
24  */
25 #define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt,       \
26 							__func__, ##a)
27 #define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \
28 					 __FILE__, __LINE__, __func__)
29 #define DCCP_BUG(a...)       do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0)
30 #define DCCP_BUG_ON(cond)    do { if (unlikely((cond) != 0))		   \
31 				     DCCP_BUG("\"%s\" holds (exception!)", \
32 					      __stringify(cond));          \
33 			     } while (0)
34 
35 #define DCCP_PRINTK(enable, fmt, args...)	do { if (enable)	     \
36 							printk(fmt, ##args); \
37 						} while(0)
38 #define DCCP_PR_DEBUG(enable, fmt, a...)	DCCP_PRINTK(enable, KERN_DEBUG \
39 						  "%s: " fmt, __func__, ##a)
40 
41 #ifdef CONFIG_IP_DCCP_DEBUG
42 extern bool dccp_debug;
43 #define dccp_pr_debug(format, a...)	  DCCP_PR_DEBUG(dccp_debug, format, ##a)
44 #define dccp_pr_debug_cat(format, a...)   DCCP_PRINTK(dccp_debug, format, ##a)
45 #define dccp_debug(fmt, a...)		  dccp_pr_debug_cat(KERN_DEBUG fmt, ##a)
46 #else
47 #define dccp_pr_debug(format, a...)
48 #define dccp_pr_debug_cat(format, a...)
49 #define dccp_debug(format, a...)
50 #endif
51 
52 extern struct inet_hashinfo dccp_hashinfo;
53 
54 extern struct percpu_counter dccp_orphan_count;
55 
56 extern void dccp_time_wait(struct sock *sk, int state, int timeo);
57 
58 /*
59  *  Set safe upper bounds for header and option length. Since Data Offset is 8
60  *  bits (RFC 4340, sec. 5.1), the total header length can never be more than
61  *  4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
62  *    - DCCP-Response with ACK Subheader and 4 bytes of Service code      OR
63  *    - DCCP-Reset    with ACK Subheader and 4 bytes of Reset Code fields
64  *  Hence a safe upper bound for the maximum option length is 1020-28 = 992
65  */
66 #define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(uint32_t))
67 #define DCCP_MAX_PACKET_HDR 28
68 #define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
69 #define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
70 
71 /* Upper bound for initial feature-negotiation overhead (padded to 32 bits) */
72 #define DCCP_FEATNEG_OVERHEAD	 (32 * sizeof(uint32_t))
73 
74 #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
75 				     * state, about 60 seconds */
76 
77 /* RFC 1122, 4.2.3.1 initial RTO value */
78 #define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
79 
80 /*
81  * The maximum back-off value for retransmissions. This is needed for
82  *  - retransmitting client-Requests (sec. 8.1.1),
83  *  - retransmitting Close/CloseReq when closing (sec. 8.3),
84  *  - feature-negotiation retransmission (sec. 6.6.3),
85  *  - Acks in client-PARTOPEN state (sec. 8.1.5).
86  */
87 #define DCCP_RTO_MAX ((unsigned)(64 * HZ))
88 
89 /*
90  * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4
91  */
92 #define DCCP_SANE_RTT_MIN	100
93 #define DCCP_FALLBACK_RTT	(USEC_PER_SEC / 5)
94 #define DCCP_SANE_RTT_MAX	(3 * USEC_PER_SEC)
95 
96 /* sysctl variables for DCCP */
97 extern int  sysctl_dccp_request_retries;
98 extern int  sysctl_dccp_retries1;
99 extern int  sysctl_dccp_retries2;
100 extern int  sysctl_dccp_tx_qlen;
101 extern int  sysctl_dccp_sync_ratelimit;
102 
103 /*
104  *	48-bit sequence number arithmetic (signed and unsigned)
105  */
106 #define INT48_MIN	  0x800000000000LL		/* 2^47	    */
107 #define UINT48_MAX	  0xFFFFFFFFFFFFLL		/* 2^48 - 1 */
108 #define COMPLEMENT48(x)	 (0x1000000000000LL - (x))	/* 2^48 - x */
109 #define TO_SIGNED48(x)	 (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
110 #define TO_UNSIGNED48(x) (((x) >= 0)?	     (x) :  COMPLEMENT48(-(x)))
111 #define ADD48(a, b)	 (((a) + (b)) & UINT48_MAX)
112 #define SUB48(a, b)	 ADD48((a), COMPLEMENT48(b))
113 
dccp_set_seqno(u64 * seqno,u64 value)114 static inline void dccp_set_seqno(u64 *seqno, u64 value)
115 {
116 	*seqno = value & UINT48_MAX;
117 }
118 
dccp_inc_seqno(u64 * seqno)119 static inline void dccp_inc_seqno(u64 *seqno)
120 {
121 	*seqno = ADD48(*seqno, 1);
122 }
123 
124 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
dccp_delta_seqno(const u64 seqno1,const u64 seqno2)125 static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
126 {
127 	u64 delta = SUB48(seqno2, seqno1);
128 
129 	return TO_SIGNED48(delta);
130 }
131 
132 /* is seq1 < seq2 ? */
before48(const u64 seq1,const u64 seq2)133 static inline int before48(const u64 seq1, const u64 seq2)
134 {
135 	return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
136 }
137 
138 /* is seq1 > seq2 ? */
139 #define after48(seq1, seq2)	before48(seq2, seq1)
140 
141 /* is seq2 <= seq1 <= seq3 ? */
between48(const u64 seq1,const u64 seq2,const u64 seq3)142 static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
143 {
144 	return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
145 }
146 
max48(const u64 seq1,const u64 seq2)147 static inline u64 max48(const u64 seq1, const u64 seq2)
148 {
149 	return after48(seq1, seq2) ? seq1 : seq2;
150 }
151 
152 /**
153  * dccp_loss_count - Approximate the number of lost data packets in a burst loss
154  * @s1:  last known sequence number before the loss ('hole')
155  * @s2:  first sequence number seen after the 'hole'
156  * @ndp: NDP count on packet with sequence number @s2
157  */
dccp_loss_count(const u64 s1,const u64 s2,const u64 ndp)158 static inline u64 dccp_loss_count(const u64 s1, const u64 s2, const u64 ndp)
159 {
160 	s64 delta = dccp_delta_seqno(s1, s2);
161 
162 	WARN_ON(delta < 0);
163 	delta -= ndp + 1;
164 
165 	return delta > 0 ? delta : 0;
166 }
167 
168 /**
169  * dccp_loss_free - Evaluate condition for data loss from RFC 4340, 7.7.1
170  */
dccp_loss_free(const u64 s1,const u64 s2,const u64 ndp)171 static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
172 {
173 	return dccp_loss_count(s1, s2, ndp) == 0;
174 }
175 
176 enum {
177 	DCCP_MIB_NUM = 0,
178 	DCCP_MIB_ACTIVEOPENS,			/* ActiveOpens */
179 	DCCP_MIB_ESTABRESETS,			/* EstabResets */
180 	DCCP_MIB_CURRESTAB,			/* CurrEstab */
181 	DCCP_MIB_OUTSEGS,			/* OutSegs */
182 	DCCP_MIB_OUTRSTS,
183 	DCCP_MIB_ABORTONTIMEOUT,
184 	DCCP_MIB_TIMEOUTS,
185 	DCCP_MIB_ABORTFAILED,
186 	DCCP_MIB_PASSIVEOPENS,
187 	DCCP_MIB_ATTEMPTFAILS,
188 	DCCP_MIB_OUTDATAGRAMS,
189 	DCCP_MIB_INERRS,
190 	DCCP_MIB_OPTMANDATORYERROR,
191 	DCCP_MIB_INVALIDOPT,
192 	__DCCP_MIB_MAX
193 };
194 
195 #define DCCP_MIB_MAX	__DCCP_MIB_MAX
196 struct dccp_mib {
197 	unsigned long	mibs[DCCP_MIB_MAX];
198 };
199 
200 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
201 #define DCCP_INC_STATS(field)	    SNMP_INC_STATS(dccp_statistics, field)
202 #define DCCP_INC_STATS_BH(field)    SNMP_INC_STATS_BH(dccp_statistics, field)
203 #define DCCP_DEC_STATS(field)	    SNMP_DEC_STATS(dccp_statistics, field)
204 
205 /*
206  * 	Checksumming routines
207  */
dccp_csum_coverage(const struct sk_buff * skb)208 static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
209 {
210 	const struct dccp_hdr* dh = dccp_hdr(skb);
211 
212 	if (dh->dccph_cscov == 0)
213 		return skb->len;
214 	return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
215 }
216 
dccp_csum_outgoing(struct sk_buff * skb)217 static inline void dccp_csum_outgoing(struct sk_buff *skb)
218 {
219 	unsigned int cov = dccp_csum_coverage(skb);
220 
221 	if (cov >= skb->len)
222 		dccp_hdr(skb)->dccph_cscov = 0;
223 
224 	skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
225 }
226 
227 extern void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb);
228 
229 extern int  dccp_retransmit_skb(struct sock *sk);
230 
231 extern void dccp_send_ack(struct sock *sk);
232 extern void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
233 				struct request_sock *rsk);
234 
235 extern void dccp_send_sync(struct sock *sk, const u64 seq,
236 			   const enum dccp_pkt_type pkt_type);
237 
238 /*
239  * TX Packet Dequeueing Interface
240  */
241 extern void		dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb);
242 extern bool		dccp_qpolicy_full(struct sock *sk);
243 extern void		dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb);
244 extern struct sk_buff	*dccp_qpolicy_top(struct sock *sk);
245 extern struct sk_buff	*dccp_qpolicy_pop(struct sock *sk);
246 extern bool		dccp_qpolicy_param_ok(struct sock *sk, __be32 param);
247 
248 /*
249  * TX Packet Output and TX Timers
250  */
251 extern void   dccp_write_xmit(struct sock *sk);
252 extern void   dccp_write_space(struct sock *sk);
253 extern void   dccp_flush_write_queue(struct sock *sk, long *time_budget);
254 
255 extern void dccp_init_xmit_timers(struct sock *sk);
dccp_clear_xmit_timers(struct sock * sk)256 static inline void dccp_clear_xmit_timers(struct sock *sk)
257 {
258 	inet_csk_clear_xmit_timers(sk);
259 }
260 
261 extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
262 
263 extern const char *dccp_packet_name(const int type);
264 
265 extern void dccp_set_state(struct sock *sk, const int state);
266 extern void dccp_done(struct sock *sk);
267 
268 extern int  dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp,
269 			    struct sk_buff const *skb);
270 
271 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
272 
273 extern struct sock *dccp_create_openreq_child(struct sock *sk,
274 					      const struct request_sock *req,
275 					      const struct sk_buff *skb);
276 
277 extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
278 
279 extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
280 					      struct sk_buff *skb,
281 					      struct request_sock *req,
282 					      struct dst_entry *dst);
283 extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
284 				   struct request_sock *req,
285 				   struct request_sock **prev);
286 
287 extern int dccp_child_process(struct sock *parent, struct sock *child,
288 			      struct sk_buff *skb);
289 extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
290 				  struct dccp_hdr *dh, unsigned len);
291 extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
292 				const struct dccp_hdr *dh, const unsigned len);
293 
294 extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
295 extern void dccp_destroy_sock(struct sock *sk);
296 
297 extern void		dccp_close(struct sock *sk, long timeout);
298 extern struct sk_buff	*dccp_make_response(struct sock *sk,
299 					    struct dst_entry *dst,
300 					    struct request_sock *req);
301 
302 extern int	   dccp_connect(struct sock *sk);
303 extern int	   dccp_disconnect(struct sock *sk, int flags);
304 extern int	   dccp_getsockopt(struct sock *sk, int level, int optname,
305 				   char __user *optval, int __user *optlen);
306 extern int	   dccp_setsockopt(struct sock *sk, int level, int optname,
307 				   char __user *optval, unsigned int optlen);
308 #ifdef CONFIG_COMPAT
309 extern int	   compat_dccp_getsockopt(struct sock *sk,
310 				int level, int optname,
311 				char __user *optval, int __user *optlen);
312 extern int	   compat_dccp_setsockopt(struct sock *sk,
313 				int level, int optname,
314 				char __user *optval, unsigned int optlen);
315 #endif
316 extern int	   dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
317 extern int	   dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
318 				struct msghdr *msg, size_t size);
319 extern int	   dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
320 				struct msghdr *msg, size_t len, int nonblock,
321 				int flags, int *addr_len);
322 extern void	   dccp_shutdown(struct sock *sk, int how);
323 extern int	   inet_dccp_listen(struct socket *sock, int backlog);
324 extern unsigned int dccp_poll(struct file *file, struct socket *sock,
325 			     poll_table *wait);
326 extern int	   dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
327 				   int addr_len);
328 
329 extern struct sk_buff *dccp_ctl_make_reset(struct sock *sk,
330 					   struct sk_buff *skb);
331 extern int	   dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
332 extern void	   dccp_send_close(struct sock *sk, const int active);
333 extern int	   dccp_invalid_packet(struct sk_buff *skb);
334 extern u32	   dccp_sample_rtt(struct sock *sk, long delta);
335 
dccp_bad_service_code(const struct sock * sk,const __be32 service)336 static inline int dccp_bad_service_code(const struct sock *sk,
337 					const __be32 service)
338 {
339 	const struct dccp_sock *dp = dccp_sk(sk);
340 
341 	if (dp->dccps_service == service)
342 		return 0;
343 	return !dccp_list_has_service(dp->dccps_service_list, service);
344 }
345 
346 /**
347  * dccp_skb_cb  -  DCCP per-packet control information
348  * @dccpd_type: one of %dccp_pkt_type (or unknown)
349  * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
350  * @dccpd_reset_code: one of %dccp_reset_codes
351  * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
352  * @dccpd_opt_len: total length of all options (5.8) in the packet
353  * @dccpd_seq: sequence number
354  * @dccpd_ack_seq: acknowledgment number subheader field value
355  * This is used for transmission as well as for reception.
356  */
357 struct dccp_skb_cb {
358 	union {
359 		struct inet_skb_parm	h4;
360 #if IS_ENABLED(CONFIG_IPV6)
361 		struct inet6_skb_parm	h6;
362 #endif
363 	} header;
364 	__u8  dccpd_type:4;
365 	__u8  dccpd_ccval:4;
366 	__u8  dccpd_reset_code,
367 	      dccpd_reset_data[3];
368 	__u16 dccpd_opt_len;
369 	__u64 dccpd_seq;
370 	__u64 dccpd_ack_seq;
371 };
372 
373 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
374 
375 /* RFC 4340, sec. 7.7 */
dccp_non_data_packet(const struct sk_buff * skb)376 static inline int dccp_non_data_packet(const struct sk_buff *skb)
377 {
378 	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
379 
380 	return type == DCCP_PKT_ACK	 ||
381 	       type == DCCP_PKT_CLOSE	 ||
382 	       type == DCCP_PKT_CLOSEREQ ||
383 	       type == DCCP_PKT_RESET	 ||
384 	       type == DCCP_PKT_SYNC	 ||
385 	       type == DCCP_PKT_SYNCACK;
386 }
387 
388 /* RFC 4340, sec. 7.7 */
dccp_data_packet(const struct sk_buff * skb)389 static inline int dccp_data_packet(const struct sk_buff *skb)
390 {
391 	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
392 
393 	return type == DCCP_PKT_DATA	 ||
394 	       type == DCCP_PKT_DATAACK  ||
395 	       type == DCCP_PKT_REQUEST  ||
396 	       type == DCCP_PKT_RESPONSE;
397 }
398 
dccp_packet_without_ack(const struct sk_buff * skb)399 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
400 {
401 	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
402 
403 	return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
404 }
405 
406 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
407 
dccp_hdr_set_seq(struct dccp_hdr * dh,const u64 gss)408 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
409 {
410 	struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
411 							   sizeof(*dh));
412 	dh->dccph_seq2 = 0;
413 	dh->dccph_seq = htons((gss >> 32) & 0xfffff);
414 	dhx->dccph_seq_low = htonl(gss & 0xffffffff);
415 }
416 
dccp_hdr_set_ack(struct dccp_hdr_ack_bits * dhack,const u64 gsr)417 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
418 				    const u64 gsr)
419 {
420 	dhack->dccph_reserved1 = 0;
421 	dhack->dccph_ack_nr_high = htons(gsr >> 32);
422 	dhack->dccph_ack_nr_low  = htonl(gsr & 0xffffffff);
423 }
424 
dccp_update_gsr(struct sock * sk,u64 seq)425 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
426 {
427 	struct dccp_sock *dp = dccp_sk(sk);
428 
429 	if (after48(seq, dp->dccps_gsr))
430 		dp->dccps_gsr = seq;
431 	/* Sequence validity window depends on remote Sequence Window (7.5.1) */
432 	dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4);
433 	/*
434 	 * Adjust SWL so that it is not below ISR. In contrast to RFC 4340,
435 	 * 7.5.1 we perform this check beyond the initial handshake: W/W' are
436 	 * always > 32, so for the first W/W' packets in the lifetime of a
437 	 * connection we always have to adjust SWL.
438 	 * A second reason why we are doing this is that the window depends on
439 	 * the feature-remote value of Sequence Window: nothing stops the peer
440 	 * from updating this value while we are busy adjusting SWL for the
441 	 * first W packets (we would have to count from scratch again then).
442 	 * Therefore it is safer to always make sure that the Sequence Window
443 	 * is not artificially extended by a peer who grows SWL downwards by
444 	 * continually updating the feature-remote Sequence-Window.
445 	 * If sequence numbers wrap it is bad luck. But that will take a while
446 	 * (48 bit), and this measure prevents Sequence-number attacks.
447 	 */
448 	if (before48(dp->dccps_swl, dp->dccps_isr))
449 		dp->dccps_swl = dp->dccps_isr;
450 	dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4);
451 }
452 
dccp_update_gss(struct sock * sk,u64 seq)453 static inline void dccp_update_gss(struct sock *sk, u64 seq)
454 {
455 	struct dccp_sock *dp = dccp_sk(sk);
456 
457 	dp->dccps_gss = seq;
458 	/* Ack validity window depends on local Sequence Window value (7.5.1) */
459 	dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win);
460 	/* Adjust AWL so that it is not below ISS - see comment above for SWL */
461 	if (before48(dp->dccps_awl, dp->dccps_iss))
462 		dp->dccps_awl = dp->dccps_iss;
463 	dp->dccps_awh = dp->dccps_gss;
464 }
465 
dccp_ackvec_pending(const struct sock * sk)466 static inline int dccp_ackvec_pending(const struct sock *sk)
467 {
468 	return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL &&
469 	       !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec);
470 }
471 
dccp_ack_pending(const struct sock * sk)472 static inline int dccp_ack_pending(const struct sock *sk)
473 {
474 	return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk);
475 }
476 
477 extern int  dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val);
478 extern int  dccp_feat_finalise_settings(struct dccp_sock *dp);
479 extern int  dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq);
480 extern int  dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*,
481 				  struct sk_buff *skb);
482 extern int  dccp_feat_activate_values(struct sock *sk, struct list_head *fn);
483 extern void dccp_feat_list_purge(struct list_head *fn_list);
484 
485 extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
486 extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
487 extern int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed);
488 extern u32 dccp_timestamp(void);
489 extern void dccp_timestamping_init(void);
490 extern int dccp_insert_option(struct sk_buff *skb, unsigned char option,
491 			      const void *value, unsigned char len);
492 
493 #ifdef CONFIG_SYSCTL
494 extern int dccp_sysctl_init(void);
495 extern void dccp_sysctl_exit(void);
496 #else
dccp_sysctl_init(void)497 static inline int dccp_sysctl_init(void)
498 {
499 	return 0;
500 }
501 
dccp_sysctl_exit(void)502 static inline void dccp_sysctl_exit(void)
503 {
504 }
505 #endif
506 
507 #endif /* _DCCP_H */
508