dccp_tfrc.h

DCCP协议在linux下的C编程实现 linux C

/*
 * Copyright (c) 2003  Nils-Erik Mattsson 
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $Id: dccp_tfrc.h,v 1.1 2004/09/30 23:00:50 bjohog Exp $
 */


#ifndef _NETINET_DCCP_TFRC_H_
#define _NETINET_DCCP_TFRC_H_

#define TFRC_STD_PACKET_SIZE    256
#define TFRC_MIN_PACKET_SIZE    16
#define TFRC_MAX_PACKET_SIZE    65535

#define TFRC_OPSYS_TIME_GRAN    10000
#define TFRC_WIN_COUNT_LIMIT    256
#define TFRC_WIN_COUNT_PER_RTT  4
#define TFRC_SMALLEST_P         0.00004
/* 
 * TFRC sender 
 */

/* TFRC specific dccp options */
#define TFRC_OPT_WINDOW_COUNT	128

/* TFRC sender states */
#define TFRC_SSTATE_NO_SENT     1
#define TFRC_SSTATE_NO_FBACK	2
#define TFRC_SSTATE_FBACK	3
#define TFRC_SSTATE_TERM	4

/* Mechanism parameters */
#define TFRC_INITIAL_TIMEOUT    2
#define TFRC_MAX_BACK_OFF_TIME  64
#define TFRC_RTT_FILTER_CONST   0.9
#define TFRC_SEND_WAIT_TERM     20

/* Packet history */
STAILQ_HEAD(s_hist_head,s_hist_entry); 
 
struct s_hist_entry {
  STAILQ_ENTRY(s_hist_entry) linfo;    /* Tail queue. */
  u_int32_t seq;            /* Sequence number */
  struct timeval t_sent;    /* When the packet was sent */
  u_int8_t win_count;       /* Windowcounter for packet */
};


/* TFRC sender congestion control block (ccb) */
struct tfrc_send_ccb {
#ifdef LINUX_FROM_BSD
	mtx mutex;
#else
  struct mtx mutex;        /* Lock for this structure */
#endif
  struct dccpcb *pcb;       /* Pointer to associated dccpcb */
  u_int8_t     state;      /* Sender state */

  double        x;          /* Current sending rate */
  double        x_recv;     /* Receive rate */
  double        x_calc;     /* Calculated send (?) rate */ 

  u_int16_t    s;          /* Packet size */
 
  u_int32_t    rtt;        /* Estimate of current round trip time */
  double        p;          /* Current loss event rate */  
  u_int8_t     last_win_count; /* Last window counter sent */
  struct timeval t_last_win_count; /* Timestamp of earliest packet with
				      last_win_count value sent */
  struct callout_handle ch_nftimer;  /* Handle to no feedback timer */
  int stopnftimer;
  u_int8_t     idle;
  u_int32_t    t_rto;      /* Time out value = 4*rtt */
  struct timeval t_ld;        /* Time last doubled during slow start */

  struct timeval t_nom,    /* Nominal send time of next packet */
                 t_ipi,    /* Interpacket (send) interval */
                 delta;    /* Send timer delta */    

//  struct callout_handle ch_stimer;  /* Handle to scheduled send timer */ 

  struct s_hist_head hist;        /* Packet history */
  struct callout_handle term_timer;  /* Handle to scheduled send timer */ 
};

#ifdef _KERNEL

/* Functions declared in struct dccp_cc_sw */

/* Initialises the sender side
 * args: pcb  - pointer to dccpcb of associated connection
 * returns: pointer to a tfrc_send_ccb struct on success, otherwise 0
 */ 
void *tfrc_send_init(struct dccpcb *pcb); 

/* Free the sender side
 * args: ccb - ccb of sender
 */
void tfrc_send_free(void *ccb);

/* Ask TFRC wheter one can send a packet or not 
 * args: ccb  -  ccb block for current connection
 * returns: 1 if ok, else 0.
 */ 
int tfrc_send_packet(void *ccb, long datasize);

/* Notify sender that a packet has been sent 
 * args: ccb - ccb block for current connection
 *	 moreToSend - if there exists more packets to send
 *       datasize   - packet size
 */
void tfrc_send_packet_sent(void *ccb, int moreToSend, long datasize);

/* Notify that a an ack package was received (i.e. a feedback packet)
 * args: ccb  -  ccb block for current connection
 */ 
void tfrc_send_packet_recv(void *ccb,char *, int);

#endif

/* 
 * TFRC Receiver 
 */

/* TFRC specific dccp options */
#define TFRC_OPT_LOSS_RATE	192
#define TFRC_OPT_ELAPSED_TIME	193
#define TFRC_OPT_RECEIVE_RATE	194

/* TFRC receiver states */
#define TFRC_RSTATE_NO_DATA	1
#define TFRC_RSTATE_DATA	2
#define TFRC_RSTATE_TERM        127

/* Receiver mechanism parameters */
#define TFRC_RECV_NEW_SEQ_RANGE 10000000   /* seq_num x,y; 
					      if y-x is smaller than this 
					      number (note, wrap around)
					      then y is newer than x */
#define TFRC_RECV_NUM_LATE_LOSS 3          /* number of later packets received 
					      before one is considered lost */
					      
#define TFRC_RECV_IVAL_F_LENGTH  8          /* length(w[]) */

/* Packet history */
STAILQ_HEAD(r_hist_head,r_hist_entry); 
 
struct r_hist_entry {
  STAILQ_ENTRY(r_hist_entry) linfo;    /* Tail queue. */
  u_int32_t seq;            /* Sequence number */
  struct timeval t_recv;    /* When the packet was received */
  u_int8_t win_count;       /* Window counter for that packet */
  u_int8_t type;            /* Packet type received */
  u_int8_t ndp;             /* no data packets value */
};

/* Loss interval history */
TAILQ_HEAD(li_hist_head,li_hist_entry); 
 
struct li_hist_entry {
  TAILQ_ENTRY(li_hist_entry) linfo;    /* Tail queue. */
  u_int32_t interval;       /* Loss interval */
  u_int32_t seq;            /* Sequence number of the packet that started 
			       the interval */
  u_int8_t win_count;       /* Window counter for previous received packet */
};

/* TFRC receiver congestion control block (ccb) */
struct tfrc_recv_ccb {
#ifdef LINUX_FROM_BSD
	mtx mutex;
#else
  struct mtx mutex;                 /* Lock for this structure */
#endif
  struct dccpcb *pcb;               /* Pointer to associated dccpcb */
  u_int8_t     state;               /* Receiver state */

  double        p;                   /* Loss event rate */
 
  struct li_hist_head li_hist;      /* Loss interval history */

  u_int8_t     last_counter;        /* Highest value of the window counter
                                       received when last feedback was sent */
  u_int32_t    seq_last_counter;    /* Sequence number of the packet above */

  struct timeval t_last_feedback;   /* Timestamp of when last feedback was sent */
  u_int32_t    bytes_recv;          /* Bytes received since t_last_feedback */

  struct r_hist_head hist;          /* Packet history */

  u_int16_t    s;                   /* Packet size */
};

#ifdef _KERNEL

/* Functions declared in struct dccp_cc_sw */

/* Initialises the receiver side
 * args: pcb  -  pointer to dccpcb of associated connection
 * returns: pointer to a tfrc_recv_ccb struct on success, otherwise 0
 */ 
void *tfrc_recv_init(struct dccpcb *pcb); 

/* Free the receiver side
 * args: ccb - ccb of recevier
 */
void tfrc_recv_free(void *ccb);

/*
 * Tell TFRC that a packet has been received
 * args: ccb  -  ccb block for current connection 
 */
void tfrc_recv_packet_recv(void *ccb, char *, int);

#endif

#endif