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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, ...)						\
26  	net_warn_ratelimited("%s: " fmt, __func__, ##__VA_ARGS__)
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  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 int)(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 int)(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(field)	__SNMP_INC_STATS(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  void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb);
228  
229  int dccp_retransmit_skb(struct sock *sk);
230  
231  void dccp_send_ack(struct sock *sk);
232  void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
233  			 struct request_sock *rsk);
234  
235  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  void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb);
242  bool dccp_qpolicy_full(struct sock *sk);
243  void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb);
244  struct sk_buff *dccp_qpolicy_top(struct sock *sk);
245  struct sk_buff *dccp_qpolicy_pop(struct sock *sk);
246  bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param);
247  
248  /*
249   * TX Packet Output and TX Timers
250   */
251  void dccp_write_xmit(struct sock *sk);
252  void dccp_write_space(struct sock *sk);
253  void dccp_flush_write_queue(struct sock *sk, long *time_budget);
254  
255  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  unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
262  
263  const char *dccp_packet_name(const int type);
264  
265  void dccp_set_state(struct sock *sk, const int state);
266  void dccp_done(struct sock *sk);
267  
268  int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp,
269  		    struct sk_buff const *skb);
270  
271  int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
272  
273  struct sock *dccp_create_openreq_child(const struct sock *sk,
274  				       const struct request_sock *req,
275  				       const struct sk_buff *skb);
276  
277  int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
278  
279  struct sock *dccp_v4_request_recv_sock(const struct sock *sk, struct sk_buff *skb,
280  				       struct request_sock *req,
281  				       struct dst_entry *dst,
282  				       struct request_sock *req_unhash,
283  				       bool *own_req);
284  struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
285  			    struct request_sock *req);
286  
287  int dccp_child_process(struct sock *parent, struct sock *child,
288  		       struct sk_buff *skb);
289  int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
290  			   struct dccp_hdr *dh, unsigned int len);
291  int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
292  			 const struct dccp_hdr *dh, const unsigned int len);
293  
294  int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
295  void dccp_destroy_sock(struct sock *sk);
296  
297  void dccp_close(struct sock *sk, long timeout);
298  struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst,
299  				   struct request_sock *req);
300  
301  int dccp_connect(struct sock *sk);
302  int dccp_disconnect(struct sock *sk, int flags);
303  int dccp_getsockopt(struct sock *sk, int level, int optname,
304  		    char __user *optval, int __user *optlen);
305  int dccp_setsockopt(struct sock *sk, int level, int optname,
306  		    char __user *optval, unsigned int optlen);
307  #ifdef CONFIG_COMPAT
308  int compat_dccp_getsockopt(struct sock *sk, int level, int optname,
309  			   char __user *optval, int __user *optlen);
310  int compat_dccp_setsockopt(struct sock *sk, int level, int optname,
311  			   char __user *optval, unsigned int optlen);
312  #endif
313  int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
314  int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
315  int dccp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
316  		 int flags, int *addr_len);
317  void dccp_shutdown(struct sock *sk, int how);
318  int inet_dccp_listen(struct socket *sock, int backlog);
319  unsigned int dccp_poll(struct file *file, struct socket *sock,
320  		       poll_table *wait);
321  int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
322  void dccp_req_err(struct sock *sk, u64 seq);
323  
324  struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *skb);
325  int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
326  void dccp_send_close(struct sock *sk, const int active);
327  int dccp_invalid_packet(struct sk_buff *skb);
328  u32 dccp_sample_rtt(struct sock *sk, long delta);
329  
dccp_bad_service_code(const struct sock * sk,const __be32 service)330  static inline bool dccp_bad_service_code(const struct sock *sk,
331  					const __be32 service)
332  {
333  	const struct dccp_sock *dp = dccp_sk(sk);
334  
335  	if (dp->dccps_service == service)
336  		return false;
337  	return !dccp_list_has_service(dp->dccps_service_list, service);
338  }
339  
340  /**
341   * dccp_skb_cb  -  DCCP per-packet control information
342   * @dccpd_type: one of %dccp_pkt_type (or unknown)
343   * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
344   * @dccpd_reset_code: one of %dccp_reset_codes
345   * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
346   * @dccpd_opt_len: total length of all options (5.8) in the packet
347   * @dccpd_seq: sequence number
348   * @dccpd_ack_seq: acknowledgment number subheader field value
349   *
350   * This is used for transmission as well as for reception.
351   */
352  struct dccp_skb_cb {
353  	union {
354  		struct inet_skb_parm	h4;
355  #if IS_ENABLED(CONFIG_IPV6)
356  		struct inet6_skb_parm	h6;
357  #endif
358  	} header;
359  	__u8  dccpd_type:4;
360  	__u8  dccpd_ccval:4;
361  	__u8  dccpd_reset_code,
362  	      dccpd_reset_data[3];
363  	__u16 dccpd_opt_len;
364  	__u64 dccpd_seq;
365  	__u64 dccpd_ack_seq;
366  };
367  
368  #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
369  
370  /* RFC 4340, sec. 7.7 */
dccp_non_data_packet(const struct sk_buff * skb)371  static inline int dccp_non_data_packet(const struct sk_buff *skb)
372  {
373  	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
374  
375  	return type == DCCP_PKT_ACK	 ||
376  	       type == DCCP_PKT_CLOSE	 ||
377  	       type == DCCP_PKT_CLOSEREQ ||
378  	       type == DCCP_PKT_RESET	 ||
379  	       type == DCCP_PKT_SYNC	 ||
380  	       type == DCCP_PKT_SYNCACK;
381  }
382  
383  /* RFC 4340, sec. 7.7 */
dccp_data_packet(const struct sk_buff * skb)384  static inline int dccp_data_packet(const struct sk_buff *skb)
385  {
386  	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
387  
388  	return type == DCCP_PKT_DATA	 ||
389  	       type == DCCP_PKT_DATAACK  ||
390  	       type == DCCP_PKT_REQUEST  ||
391  	       type == DCCP_PKT_RESPONSE;
392  }
393  
dccp_packet_without_ack(const struct sk_buff * skb)394  static inline int dccp_packet_without_ack(const struct sk_buff *skb)
395  {
396  	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
397  
398  	return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
399  }
400  
401  #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
402  
dccp_hdr_set_seq(struct dccp_hdr * dh,const u64 gss)403  static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
404  {
405  	struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
406  							   sizeof(*dh));
407  	dh->dccph_seq2 = 0;
408  	dh->dccph_seq = htons((gss >> 32) & 0xfffff);
409  	dhx->dccph_seq_low = htonl(gss & 0xffffffff);
410  }
411  
dccp_hdr_set_ack(struct dccp_hdr_ack_bits * dhack,const u64 gsr)412  static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
413  				    const u64 gsr)
414  {
415  	dhack->dccph_reserved1 = 0;
416  	dhack->dccph_ack_nr_high = htons(gsr >> 32);
417  	dhack->dccph_ack_nr_low  = htonl(gsr & 0xffffffff);
418  }
419  
dccp_update_gsr(struct sock * sk,u64 seq)420  static inline void dccp_update_gsr(struct sock *sk, u64 seq)
421  {
422  	struct dccp_sock *dp = dccp_sk(sk);
423  
424  	if (after48(seq, dp->dccps_gsr))
425  		dp->dccps_gsr = seq;
426  	/* Sequence validity window depends on remote Sequence Window (7.5.1) */
427  	dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4);
428  	/*
429  	 * Adjust SWL so that it is not below ISR. In contrast to RFC 4340,
430  	 * 7.5.1 we perform this check beyond the initial handshake: W/W' are
431  	 * always > 32, so for the first W/W' packets in the lifetime of a
432  	 * connection we always have to adjust SWL.
433  	 * A second reason why we are doing this is that the window depends on
434  	 * the feature-remote value of Sequence Window: nothing stops the peer
435  	 * from updating this value while we are busy adjusting SWL for the
436  	 * first W packets (we would have to count from scratch again then).
437  	 * Therefore it is safer to always make sure that the Sequence Window
438  	 * is not artificially extended by a peer who grows SWL downwards by
439  	 * continually updating the feature-remote Sequence-Window.
440  	 * If sequence numbers wrap it is bad luck. But that will take a while
441  	 * (48 bit), and this measure prevents Sequence-number attacks.
442  	 */
443  	if (before48(dp->dccps_swl, dp->dccps_isr))
444  		dp->dccps_swl = dp->dccps_isr;
445  	dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4);
446  }
447  
dccp_update_gss(struct sock * sk,u64 seq)448  static inline void dccp_update_gss(struct sock *sk, u64 seq)
449  {
450  	struct dccp_sock *dp = dccp_sk(sk);
451  
452  	dp->dccps_gss = seq;
453  	/* Ack validity window depends on local Sequence Window value (7.5.1) */
454  	dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win);
455  	/* Adjust AWL so that it is not below ISS - see comment above for SWL */
456  	if (before48(dp->dccps_awl, dp->dccps_iss))
457  		dp->dccps_awl = dp->dccps_iss;
458  	dp->dccps_awh = dp->dccps_gss;
459  }
460  
dccp_ackvec_pending(const struct sock * sk)461  static inline int dccp_ackvec_pending(const struct sock *sk)
462  {
463  	return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL &&
464  	       !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec);
465  }
466  
dccp_ack_pending(const struct sock * sk)467  static inline int dccp_ack_pending(const struct sock *sk)
468  {
469  	return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk);
470  }
471  
472  int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val);
473  int dccp_feat_finalise_settings(struct dccp_sock *dp);
474  int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq);
475  int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*,
476  			  struct sk_buff *skb);
477  int dccp_feat_activate_values(struct sock *sk, struct list_head *fn);
478  void dccp_feat_list_purge(struct list_head *fn_list);
479  
480  int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
481  int dccp_insert_options_rsk(struct dccp_request_sock *, struct sk_buff *);
482  u32 dccp_timestamp(void);
483  void dccp_timestamping_init(void);
484  int dccp_insert_option(struct sk_buff *skb, unsigned char option,
485  		       const void *value, unsigned char len);
486  
487  #ifdef CONFIG_SYSCTL
488  int dccp_sysctl_init(void);
489  void dccp_sysctl_exit(void);
490  #else
dccp_sysctl_init(void)491  static inline int dccp_sysctl_init(void)
492  {
493  	return 0;
494  }
495  
dccp_sysctl_exit(void)496  static inline void dccp_sysctl_exit(void)
497  {
498  }
499  #endif
500  
501  #endif /* _DCCP_H */
502