net/dccp/dccp.h - kernel/msm-5.4 - Gitiles

 #ifndef _DCCP_H
 #define _DCCP_H
 /*
  *  net/dccp/dccp.h
  *
  *  An implementation of the DCCP protocol
  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  *  Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
  *
  *	This program is free software; you can redistribute it and/or modify it
  *	under the terms of the GNU General Public License version 2 as
  *	published by the Free Software Foundation.
  */

 #include <linux/dccp.h>
 #include <linux/ktime.h>
 #include <net/snmp.h>
 #include <net/sock.h>
 #include <net/tcp.h>
 #include "ackvec.h"

 /*
  * 	DCCP - specific warning and debugging macros.
  */
 #define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt,       \
 							__FUNCTION__, ##a)
 #define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \
 					 __FILE__, __LINE__, __FUNCTION__)
 #define DCCP_BUG(a...)       do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0)
 #define DCCP_BUG_ON(cond)    do { if (unlikely((cond) != 0))		   \
 				     DCCP_BUG("\"%s\" holds (exception!)", \
 					      __stringify(cond));          \
 			     } while (0)

 #define DCCP_PRINTK(enable, fmt, args...)	do { if (enable)	     \
 							printk(fmt, ##args); \
 						} while(0)
 #define DCCP_PR_DEBUG(enable, fmt, a...)	DCCP_PRINTK(enable, KERN_DEBUG \
 						  "%s: " fmt, __FUNCTION__, ##a)

 #ifdef CONFIG_IP_DCCP_DEBUG
 extern int dccp_debug;
 #define dccp_pr_debug(format, a...)	  DCCP_PR_DEBUG(dccp_debug, format, ##a)
 #define dccp_pr_debug_cat(format, a...)   DCCP_PRINTK(dccp_debug, format, ##a)
 #else
 #define dccp_pr_debug(format, a...)
 #define dccp_pr_debug_cat(format, a...)
 #endif

 extern struct inet_hashinfo dccp_hashinfo;

 extern atomic_t dccp_orphan_count;

 extern void dccp_time_wait(struct sock *sk, int state, int timeo);

 /*
  *  Set safe upper bounds for header and option length. Since Data Offset is 8
  *  bits (RFC 4340, sec. 5.1), the total header length can never be more than
  *  4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
  *    - DCCP-Response with ACK Subheader and 4 bytes of Service code      OR
  *    - DCCP-Reset    with ACK Subheader and 4 bytes of Reset Code fields
  *  Hence a safe upper bound for the maximum option length is 1020-28 = 992
  */
 #define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int))
 #define DCCP_MAX_PACKET_HDR 28
 #define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
 #define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)

 #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
 				     * state, about 60 seconds */

 /* RFC 1122, 4.2.3.1 initial RTO value */
 #define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))

 #define DCCP_RTO_MAX ((unsigned)(120 * HZ)) /* FIXME: using TCP value */

 /* bounds for sampled RTT values from packet exchanges (in usec) */
 #define DCCP_SANE_RTT_MIN	100
 #define DCCP_SANE_RTT_MAX	(4 * USEC_PER_SEC)

 /* Maximal interval between probes for local resources.  */
 #define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))

 /* sysctl variables for DCCP */
 extern int  sysctl_dccp_request_retries;
 extern int  sysctl_dccp_retries1;
 extern int  sysctl_dccp_retries2;
 extern int  sysctl_dccp_feat_sequence_window;
 extern int  sysctl_dccp_feat_rx_ccid;
 extern int  sysctl_dccp_feat_tx_ccid;
 extern int  sysctl_dccp_feat_ack_ratio;
 extern int  sysctl_dccp_feat_send_ack_vector;
 extern int  sysctl_dccp_feat_send_ndp_count;
 extern int  sysctl_dccp_tx_qlen;

 /*
  *	48-bit sequence number arithmetic (signed and unsigned)
  */
 #define INT48_MIN	  0x800000000000LL		/* 2^47	    */
 #define UINT48_MAX	  0xFFFFFFFFFFFFLL		/* 2^48 - 1 */
 #define COMPLEMENT48(x)	 (0x1000000000000LL - (x))	/* 2^48 - x */
 #define TO_SIGNED48(x)	 (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
 #define TO_UNSIGNED48(x) (((x) >= 0)?	     (x) :  COMPLEMENT48(-(x)))
 #define ADD48(a, b)	 (((a) + (b)) & UINT48_MAX)
 #define SUB48(a, b)	 ADD48((a), COMPLEMENT48(b))

 static inline void dccp_set_seqno(u64 *seqno, u64 value)
 {
 	*seqno = value & UINT48_MAX;
 }

 static inline void dccp_inc_seqno(u64 *seqno)
 {
 	*seqno = ADD48(*seqno, 1);
 }

 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
 static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
 {
 	u64 delta = SUB48(seqno2, seqno1);

 	return TO_SIGNED48(delta);
 }

 /* is seq1 < seq2 ? */
 static inline int before48(const u64 seq1, const u64 seq2)
 {
 	return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
 }

 /* is seq1 > seq2 ? */
 #define after48(seq1, seq2)	before48(seq2, seq1)

 /* is seq2 <= seq1 <= seq3 ? */
 static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
 {
 	return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
 }

 static inline u64 max48(const u64 seq1, const u64 seq2)
 {
 	return after48(seq1, seq2) ? seq1 : seq2;
 }

 /* is seq1 next seqno after seq2 */
 static inline int follows48(const u64 seq1, const u64 seq2)
 {
 	return dccp_delta_seqno(seq2, seq1) == 1;
 }

 enum {
 	DCCP_MIB_NUM = 0,
 	DCCP_MIB_ACTIVEOPENS,			/* ActiveOpens */
 	DCCP_MIB_ESTABRESETS,			/* EstabResets */
 	DCCP_MIB_CURRESTAB,			/* CurrEstab */
 	DCCP_MIB_OUTSEGS,			/* OutSegs */
 	DCCP_MIB_OUTRSTS,
 	DCCP_MIB_ABORTONTIMEOUT,
 	DCCP_MIB_TIMEOUTS,
 	DCCP_MIB_ABORTFAILED,
 	DCCP_MIB_PASSIVEOPENS,
 	DCCP_MIB_ATTEMPTFAILS,
 	DCCP_MIB_OUTDATAGRAMS,
 	DCCP_MIB_INERRS,
 	DCCP_MIB_OPTMANDATORYERROR,
 	DCCP_MIB_INVALIDOPT,
 	__DCCP_MIB_MAX
 };

 #define DCCP_MIB_MAX	__DCCP_MIB_MAX
 struct dccp_mib {
 	unsigned long	mibs[DCCP_MIB_MAX];
 } __SNMP_MIB_ALIGN__;

 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
 #define DCCP_INC_STATS(field)	    SNMP_INC_STATS(dccp_statistics, field)
 #define DCCP_INC_STATS_BH(field)    SNMP_INC_STATS_BH(dccp_statistics, field)
 #define DCCP_INC_STATS_USER(field)  SNMP_INC_STATS_USER(dccp_statistics, field)
 #define DCCP_DEC_STATS(field)	    SNMP_DEC_STATS(dccp_statistics, field)
 #define DCCP_ADD_STATS_BH(field, val) \
 			SNMP_ADD_STATS_BH(dccp_statistics, field, val)
 #define DCCP_ADD_STATS_USER(field, val)	\
 			SNMP_ADD_STATS_USER(dccp_statistics, field, val)

 /*
  * 	Checksumming routines
  */
 static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
 {
 	const struct dccp_hdr* dh = dccp_hdr(skb);

 	if (dh->dccph_cscov == 0)
 		return skb->len;
 	return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
 }

 static inline void dccp_csum_outgoing(struct sk_buff *skb)
 {
 	unsigned int cov = dccp_csum_coverage(skb);

 	if (cov >= skb->len)
 		dccp_hdr(skb)->dccph_cscov = 0;

 	skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
 }

 extern void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);

 extern int  dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);

 extern void dccp_send_ack(struct sock *sk);
 extern void dccp_send_delayed_ack(struct sock *sk);
 extern void dccp_reqsk_send_ack(struct sk_buff *sk, struct request_sock *rsk);

 extern void dccp_send_sync(struct sock *sk, const u64 seq,
 			   const enum dccp_pkt_type pkt_type);

 extern void dccp_write_xmit(struct sock *sk, int block);
 extern void dccp_write_space(struct sock *sk);

 extern void dccp_init_xmit_timers(struct sock *sk);
 static inline void dccp_clear_xmit_timers(struct sock *sk)
 {
 	inet_csk_clear_xmit_timers(sk);
 }

 extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);

 extern const char *dccp_packet_name(const int type);
 extern const char *dccp_state_name(const int state);

 extern void dccp_set_state(struct sock *sk, const int state);
 extern void dccp_done(struct sock *sk);

 extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb);

 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);

 extern struct sock *dccp_create_openreq_child(struct sock *sk,
 					      const struct request_sock *req,
 					      const struct sk_buff *skb);

 extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);

 extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
 					      struct sk_buff *skb,
 					      struct request_sock *req,
 					      struct dst_entry *dst);
 extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
 				   struct request_sock *req,
 				   struct request_sock **prev);

 extern int dccp_child_process(struct sock *parent, struct sock *child,
 			      struct sk_buff *skb);
 extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 				  struct dccp_hdr *dh, unsigned len);
 extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
 				const struct dccp_hdr *dh, const unsigned len);

 extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
 extern int dccp_destroy_sock(struct sock *sk);

 extern void		dccp_close(struct sock *sk, long timeout);
 extern struct sk_buff	*dccp_make_response(struct sock *sk,
 					    struct dst_entry *dst,
 					    struct request_sock *req);

 extern int	   dccp_connect(struct sock *sk);
 extern int	   dccp_disconnect(struct sock *sk, int flags);
 extern void	   dccp_hash(struct sock *sk);
 extern void	   dccp_unhash(struct sock *sk);
 extern int	   dccp_getsockopt(struct sock *sk, int level, int optname,
 				   char __user *optval, int __user *optlen);
 extern int	   dccp_setsockopt(struct sock *sk, int level, int optname,
 				   char __user *optval, int optlen);
 #ifdef CONFIG_COMPAT
 extern int	   compat_dccp_getsockopt(struct sock *sk,
 				int level, int optname,
 				char __user *optval, int __user *optlen);
 extern int	   compat_dccp_setsockopt(struct sock *sk,
 				int level, int optname,
 				char __user *optval, int optlen);
 #endif
 extern int	   dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 extern int	   dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
 				struct msghdr *msg, size_t size);
 extern int	   dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
 				struct msghdr *msg, size_t len, int nonblock,
 				int flags, int *addr_len);
 extern void	   dccp_shutdown(struct sock *sk, int how);
 extern int	   inet_dccp_listen(struct socket *sock, int backlog);
 extern unsigned int dccp_poll(struct file *file, struct socket *sock,
 			     poll_table *wait);
 extern int	   dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
 				   int addr_len);

 extern int	   dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
 extern void	   dccp_send_close(struct sock *sk, const int active);
 extern int	   dccp_invalid_packet(struct sk_buff *skb);
 extern u32	   dccp_sample_rtt(struct sock *sk, ktime_t t_recv,
 				   ktime_t *t_history);

 static inline int dccp_bad_service_code(const struct sock *sk,
 					const __be32 service)
 {
 	const struct dccp_sock *dp = dccp_sk(sk);

 	if (dp->dccps_service == service)
 		return 0;
 	return !dccp_list_has_service(dp->dccps_service_list, service);
 }

 struct dccp_skb_cb {
 	__u8  dccpd_type:4;
 	__u8  dccpd_ccval:4;
 	__u8  dccpd_reset_code;
 	__u16 dccpd_opt_len;
 	__u64 dccpd_seq;
 	__u64 dccpd_ack_seq;
 };

 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))

 static inline int dccp_non_data_packet(const struct sk_buff *skb)
 {
 	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;

 	return type == DCCP_PKT_ACK	 ||
 	       type == DCCP_PKT_CLOSE	 ||
 	       type == DCCP_PKT_CLOSEREQ ||
 	       type == DCCP_PKT_RESET	 ||
 	       type == DCCP_PKT_SYNC	 ||
 	       type == DCCP_PKT_SYNCACK;
 }

 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
 {
 	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;

 	return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
 }

 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)

 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
 {
 	struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
 							   sizeof(*dh));
 	dh->dccph_seq2 = 0;
 	dh->dccph_seq = htons((gss >> 32) & 0xfffff);
 	dhx->dccph_seq_low = htonl(gss & 0xffffffff);
 }

 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
 				    const u64 gsr)
 {
 	dhack->dccph_reserved1 = 0;
 	dhack->dccph_ack_nr_high = htons(gsr >> 32);
 	dhack->dccph_ack_nr_low  = htonl(gsr & 0xffffffff);
 }

 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
 	const struct dccp_minisock *dmsk = dccp_msk(sk);

 	dp->dccps_gsr = seq;
 	dccp_set_seqno(&dp->dccps_swl,
 		       dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
 	dccp_set_seqno(&dp->dccps_swh,
 		       dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
 }

 static inline void dccp_update_gss(struct sock *sk, u64 seq)
 {
 	struct dccp_sock *dp = dccp_sk(sk);

 	dp->dccps_awh = dp->dccps_gss = seq;
 	dccp_set_seqno(&dp->dccps_awl,
 		       (dp->dccps_gss -
 			dccp_msk(sk)->dccpms_sequence_window + 1));
 }

 static inline int dccp_ack_pending(const struct sock *sk)
 {
 	const struct dccp_sock *dp = dccp_sk(sk);
 	return dp->dccps_timestamp_echo != 0 ||
 #ifdef CONFIG_IP_DCCP_ACKVEC
 	       (dccp_msk(sk)->dccpms_send_ack_vector &&
 		dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
 #endif
 	       inet_csk_ack_scheduled(sk);
 }

 extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
 extern int dccp_insert_option_elapsed_time(struct sock *sk,
 					    struct sk_buff *skb,
 					    u32 elapsed_time);
 extern int dccp_insert_option_timestamp(struct sock *sk,
 					 struct sk_buff *skb);
 extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
 			       unsigned char option,
 			       const void *value, unsigned char len);

 #ifdef CONFIG_SYSCTL
 extern int dccp_sysctl_init(void);
 extern void dccp_sysctl_exit(void);
 #else
 static inline int dccp_sysctl_init(void)
 {
 	return 0;
 }

 static inline void dccp_sysctl_exit(void)
 {
 }
 #endif

 #endif /* _DCCP_H */
	#ifndef _DCCP_H
	#define _DCCP_H
	/*
	* net/dccp/dccp.h
	*
	* An implementation of the DCCP protocol
	* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
	* Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/dccp.h>
	#include <linux/ktime.h>
	#include <net/snmp.h>
	#include <net/sock.h>
	#include <net/tcp.h>
	#include "ackvec.h"

	/*
	* DCCP - specific warning and debugging macros.
	*/
	#define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt, \
	__FUNCTION__, ##a)
	#define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \
	__FILE__, __LINE__, __FUNCTION__)
	#define DCCP_BUG(a...) do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0)
	#define DCCP_BUG_ON(cond) do { if (unlikely((cond) != 0)) \
	DCCP_BUG("\"%s\" holds (exception!)", \
	__stringify(cond)); \
	} while (0)

	#define DCCP_PRINTK(enable, fmt, args...) do { if (enable) \
	printk(fmt, ##args); \
	} while(0)
	#define DCCP_PR_DEBUG(enable, fmt, a...) DCCP_PRINTK(enable, KERN_DEBUG \
	"%s: " fmt, __FUNCTION__, ##a)

	#ifdef CONFIG_IP_DCCP_DEBUG
	extern int dccp_debug;
	#define dccp_pr_debug(format, a...) DCCP_PR_DEBUG(dccp_debug, format, ##a)
	#define dccp_pr_debug_cat(format, a...) DCCP_PRINTK(dccp_debug, format, ##a)
	#else
	#define dccp_pr_debug(format, a...)
	#define dccp_pr_debug_cat(format, a...)
	#endif

	extern struct inet_hashinfo dccp_hashinfo;

	extern atomic_t dccp_orphan_count;

	extern void dccp_time_wait(struct sock *sk, int state, int timeo);

	/*
	* Set safe upper bounds for header and option length. Since Data Offset is 8
	* bits (RFC 4340, sec. 5.1), the total header length can never be more than
	* 4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
	* - DCCP-Response with ACK Subheader and 4 bytes of Service code OR
	* - DCCP-Reset with ACK Subheader and 4 bytes of Reset Code fields
	* Hence a safe upper bound for the maximum option length is 1020-28 = 992
	*/
	#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int))
	#define DCCP_MAX_PACKET_HDR 28
	#define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
	#define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)

	#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
	* state, about 60 seconds */

	/* RFC 1122, 4.2.3.1 initial RTO value */
	#define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))

	#define DCCP_RTO_MAX ((unsigned)(120 * HZ)) /* FIXME: using TCP value */

	/* bounds for sampled RTT values from packet exchanges (in usec) */
	#define DCCP_SANE_RTT_MIN 100
	#define DCCP_SANE_RTT_MAX (4 * USEC_PER_SEC)

	/* Maximal interval between probes for local resources. */
	#define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))

	/* sysctl variables for DCCP */
	extern int sysctl_dccp_request_retries;
	extern int sysctl_dccp_retries1;
	extern int sysctl_dccp_retries2;
	extern int sysctl_dccp_feat_sequence_window;
	extern int sysctl_dccp_feat_rx_ccid;
	extern int sysctl_dccp_feat_tx_ccid;
	extern int sysctl_dccp_feat_ack_ratio;
	extern int sysctl_dccp_feat_send_ack_vector;
	extern int sysctl_dccp_feat_send_ndp_count;
	extern int sysctl_dccp_tx_qlen;

	/*
	* 48-bit sequence number arithmetic (signed and unsigned)
	*/
	#define INT48_MIN 0x800000000000LL /* 2^47 */
	#define UINT48_MAX 0xFFFFFFFFFFFFLL /* 2^48 - 1 */
	#define COMPLEMENT48(x) (0x1000000000000LL - (x)) /* 2^48 - x */
	#define TO_SIGNED48(x) (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
	#define TO_UNSIGNED48(x) (((x) >= 0)? (x) : COMPLEMENT48(-(x)))
	#define ADD48(a, b) (((a) + (b)) & UINT48_MAX)
	#define SUB48(a, b) ADD48((a), COMPLEMENT48(b))

	static inline void dccp_set_seqno(u64 *seqno, u64 value)
	{
	*seqno = value & UINT48_MAX;
	}

	static inline void dccp_inc_seqno(u64 *seqno)
	{
	seqno = ADD48(seqno, 1);
	}

	/* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
	static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
	{
	u64 delta = SUB48(seqno2, seqno1);

	return TO_SIGNED48(delta);
	}

	/* is seq1 < seq2 ? */
	static inline int before48(const u64 seq1, const u64 seq2)
	{
	return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
	}

	/* is seq1 > seq2 ? */
	#define after48(seq1, seq2) before48(seq2, seq1)

	/* is seq2 <= seq1 <= seq3 ? */
	static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
	{
	return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
	}

	static inline u64 max48(const u64 seq1, const u64 seq2)
	{
	return after48(seq1, seq2) ? seq1 : seq2;
	}

	/* is seq1 next seqno after seq2 */
	static inline int follows48(const u64 seq1, const u64 seq2)
	{
	return dccp_delta_seqno(seq2, seq1) == 1;
	}

	enum {
	DCCP_MIB_NUM = 0,
	DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */
	DCCP_MIB_ESTABRESETS, /* EstabResets */
	DCCP_MIB_CURRESTAB, /* CurrEstab */
	DCCP_MIB_OUTSEGS, /* OutSegs */
	DCCP_MIB_OUTRSTS,
	DCCP_MIB_ABORTONTIMEOUT,
	DCCP_MIB_TIMEOUTS,
	DCCP_MIB_ABORTFAILED,
	DCCP_MIB_PASSIVEOPENS,
	DCCP_MIB_ATTEMPTFAILS,
	DCCP_MIB_OUTDATAGRAMS,
	DCCP_MIB_INERRS,
	DCCP_MIB_OPTMANDATORYERROR,
	DCCP_MIB_INVALIDOPT,
	__DCCP_MIB_MAX
	};

	#define DCCP_MIB_MAX __DCCP_MIB_MAX
	struct dccp_mib {
	unsigned long mibs[DCCP_MIB_MAX];
	} __SNMP_MIB_ALIGN__;

	DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
	#define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)
	#define DCCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(dccp_statistics, field)
	#define DCCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(dccp_statistics, field)
	#define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field)
	#define DCCP_ADD_STATS_BH(field, val) \
	SNMP_ADD_STATS_BH(dccp_statistics, field, val)
	#define DCCP_ADD_STATS_USER(field, val) \
	SNMP_ADD_STATS_USER(dccp_statistics, field, val)

	/*
	* Checksumming routines
	*/
	static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
	{
	const struct dccp_hdr* dh = dccp_hdr(skb);

	if (dh->dccph_cscov == 0)
	return skb->len;
	return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
	}

	static inline void dccp_csum_outgoing(struct sk_buff *skb)
	{
	unsigned int cov = dccp_csum_coverage(skb);

	if (cov >= skb->len)
	dccp_hdr(skb)->dccph_cscov = 0;

	skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
	}

	extern void dccp_v4_send_check(struct sock sk, int len, struct sk_buff skb);

	extern int dccp_retransmit_skb(struct sock sk, struct sk_buff skb);

	extern void dccp_send_ack(struct sock *sk);
	extern void dccp_send_delayed_ack(struct sock *sk);
	extern void dccp_reqsk_send_ack(struct sk_buff sk, struct request_sock rsk);

	extern void dccp_send_sync(struct sock *sk, const u64 seq,
	const enum dccp_pkt_type pkt_type);

	extern void dccp_write_xmit(struct sock *sk, int block);
	extern void dccp_write_space(struct sock *sk);

	extern void dccp_init_xmit_timers(struct sock *sk);
	static inline void dccp_clear_xmit_timers(struct sock *sk)
	{
	inet_csk_clear_xmit_timers(sk);
	}

	extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);

	extern const char *dccp_packet_name(const int type);
	extern const char *dccp_state_name(const int state);

	extern void dccp_set_state(struct sock *sk, const int state);
	extern void dccp_done(struct sock *sk);

	extern void dccp_reqsk_init(struct request_sock req, struct sk_buff skb);

	extern int dccp_v4_conn_request(struct sock sk, struct sk_buff skb);

	extern struct sock dccp_create_openreq_child(struct sock sk,
	const struct request_sock *req,
	const struct sk_buff *skb);

	extern int dccp_v4_do_rcv(struct sock sk, struct sk_buff skb);

	extern struct sock dccp_v4_request_recv_sock(struct sock sk,
	struct sk_buff *skb,
	struct request_sock *req,
	struct dst_entry *dst);
	extern struct sock dccp_check_req(struct sock sk, struct sk_buff *skb,
	struct request_sock *req,
	struct request_sock **prev);

	extern int dccp_child_process(struct sock parent, struct sock child,
	struct sk_buff *skb);
	extern int dccp_rcv_state_process(struct sock sk, struct sk_buff skb,
	struct dccp_hdr *dh, unsigned len);
	extern int dccp_rcv_established(struct sock sk, struct sk_buff skb,
	const struct dccp_hdr *dh, const unsigned len);

	extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
	extern int dccp_destroy_sock(struct sock *sk);

	extern void dccp_close(struct sock *sk, long timeout);
	extern struct sk_buff dccp_make_response(struct sock sk,
	struct dst_entry *dst,
	struct request_sock *req);

	extern int dccp_connect(struct sock *sk);
	extern int dccp_disconnect(struct sock *sk, int flags);
	extern void dccp_hash(struct sock *sk);
	extern void dccp_unhash(struct sock *sk);
	extern int dccp_getsockopt(struct sock *sk, int level, int optname,
	char __user optval, int __user optlen);
	extern int dccp_setsockopt(struct sock *sk, int level, int optname,
	char __user *optval, int optlen);
	#ifdef CONFIG_COMPAT
	extern int compat_dccp_getsockopt(struct sock *sk,
	int level, int optname,
	char __user optval, int __user optlen);
	extern int compat_dccp_setsockopt(struct sock *sk,
	int level, int optname,
	char __user *optval, int optlen);
	#endif
	extern int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
	extern int dccp_sendmsg(struct kiocb iocb, struct sock sk,
	struct msghdr *msg, size_t size);
	extern int dccp_recvmsg(struct kiocb iocb, struct sock sk,
	struct msghdr *msg, size_t len, int nonblock,
	int flags, int *addr_len);
	extern void dccp_shutdown(struct sock *sk, int how);
	extern int inet_dccp_listen(struct socket *sock, int backlog);
	extern unsigned int dccp_poll(struct file file, struct socket sock,
	poll_table *wait);
	extern int dccp_v4_connect(struct sock sk, struct sockaddr uaddr,
	int addr_len);

	extern int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
	extern void dccp_send_close(struct sock *sk, const int active);
	extern int dccp_invalid_packet(struct sk_buff *skb);
	extern u32 dccp_sample_rtt(struct sock *sk, ktime_t t_recv,
	ktime_t *t_history);

	static inline int dccp_bad_service_code(const struct sock *sk,
	const __be32 service)
	{
	const struct dccp_sock *dp = dccp_sk(sk);

	if (dp->dccps_service == service)
	return 0;
	return !dccp_list_has_service(dp->dccps_service_list, service);
	}

	struct dccp_skb_cb {
	__u8 dccpd_type:4;
	__u8 dccpd_ccval:4;
	__u8 dccpd_reset_code;
	__u16 dccpd_opt_len;
	__u64 dccpd_seq;
	__u64 dccpd_ack_seq;
	};

	#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))

	static inline int dccp_non_data_packet(const struct sk_buff *skb)
	{
	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;

	return type == DCCP_PKT_ACK \|\|
	type == DCCP_PKT_CLOSE \|\|
	type == DCCP_PKT_CLOSEREQ \|\|
	type == DCCP_PKT_RESET \|\|
	type == DCCP_PKT_SYNC \|\|
	type == DCCP_PKT_SYNCACK;
	}

	static inline int dccp_packet_without_ack(const struct sk_buff *skb)
	{
	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;

	return type == DCCP_PKT_DATA \|\| type == DCCP_PKT_REQUEST;
	}

	#define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)

	static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
	{
	struct dccp_hdr_ext dhx = (struct dccp_hdr_ext )((void *)dh +
	sizeof(*dh));
	dh->dccph_seq2 = 0;
	dh->dccph_seq = htons((gss >> 32) & 0xfffff);
	dhx->dccph_seq_low = htonl(gss & 0xffffffff);
	}

	static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
	const u64 gsr)
	{
	dhack->dccph_reserved1 = 0;
	dhack->dccph_ack_nr_high = htons(gsr >> 32);
	dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff);
	}

	static inline void dccp_update_gsr(struct sock *sk, u64 seq)
	{
	struct dccp_sock *dp = dccp_sk(sk);
	const struct dccp_minisock *dmsk = dccp_msk(sk);

	dp->dccps_gsr = seq;
	dccp_set_seqno(&dp->dccps_swl,
	dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
	dccp_set_seqno(&dp->dccps_swh,
	dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
	}

	static inline void dccp_update_gss(struct sock *sk, u64 seq)
	{
	struct dccp_sock *dp = dccp_sk(sk);

	dp->dccps_awh = dp->dccps_gss = seq;
	dccp_set_seqno(&dp->dccps_awl,
	(dp->dccps_gss -
	dccp_msk(sk)->dccpms_sequence_window + 1));
	}

	static inline int dccp_ack_pending(const struct sock *sk)
	{
	const struct dccp_sock *dp = dccp_sk(sk);
	return dp->dccps_timestamp_echo != 0 \|\|
	#ifdef CONFIG_IP_DCCP_ACKVEC
	(dccp_msk(sk)->dccpms_send_ack_vector &&
	dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) \|\|
	#endif
	inet_csk_ack_scheduled(sk);
	}

	extern int dccp_insert_options(struct sock sk, struct sk_buff skb);
	extern int dccp_insert_option_elapsed_time(struct sock *sk,
	struct sk_buff *skb,
	u32 elapsed_time);
	extern int dccp_insert_option_timestamp(struct sock *sk,
	struct sk_buff *skb);
	extern int dccp_insert_option(struct sock sk, struct sk_buff skb,
	unsigned char option,
	const void *value, unsigned char len);

	#ifdef CONFIG_SYSCTL
	extern int dccp_sysctl_init(void);
	extern void dccp_sysctl_exit(void);
	#else
	static inline int dccp_sysctl_init(void)
	{
	return 0;
	}

	static inline void dccp_sysctl_exit(void)
	{
	}
	#endif

	#endif /* _DCCP_H */