File:  [Qemu by Fabrice Bellard] / qemu / slirp / tcp_var.h
Revision 1.1.1.3 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 16:54:42 2018 UTC (3 years ago) by root
Branches: qemu, MAIN
CVS tags: qemu0105, qemu0104, qemu0103, qemu0102, qemu0101, qemu0100, HEAD
qemu 0.10.0

    1: /*
    2:  * Copyright (c) 1982, 1986, 1993, 1994
    3:  *	The Regents of the University of California.  All rights reserved.
    4:  *
    5:  * Redistribution and use in source and binary forms, with or without
    6:  * modification, are permitted provided that the following conditions
    7:  * are met:
    8:  * 1. Redistributions of source code must retain the above copyright
    9:  *    notice, this list of conditions and the following disclaimer.
   10:  * 2. Redistributions in binary form must reproduce the above copyright
   11:  *    notice, this list of conditions and the following disclaimer in the
   12:  *    documentation and/or other materials provided with the distribution.
   13:  * 3. Neither the name of the University nor the names of its contributors
   14:  *    may be used to endorse or promote products derived from this software
   15:  *    without specific prior written permission.
   16:  *
   17:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27:  * SUCH DAMAGE.
   28:  *
   29:  *	@(#)tcp_var.h	8.3 (Berkeley) 4/10/94
   30:  * tcp_var.h,v 1.3 1994/08/21 05:27:39 paul Exp
   31:  */
   32: 
   33: #ifndef _TCP_VAR_H_
   34: #define _TCP_VAR_H_
   35: 
   36: #include "tcpip.h"
   37: #include "tcp_timer.h"
   38: 
   39: /*
   40:  * Tcp control block, one per tcp; fields:
   41:  */
   42: struct tcpcb {
   43: 	struct tcpiphdr *seg_next;	/* sequencing queue */
   44: 	struct tcpiphdr *seg_prev;
   45: 	short	t_state;		/* state of this connection */
   46: 	short	t_timer[TCPT_NTIMERS];	/* tcp timers */
   47: 	short	t_rxtshift;		/* log(2) of rexmt exp. backoff */
   48: 	short	t_rxtcur;		/* current retransmit value */
   49: 	short	t_dupacks;		/* consecutive dup acks recd */
   50: 	u_short	t_maxseg;		/* maximum segment size */
   51: 	char	t_force;		/* 1 if forcing out a byte */
   52: 	u_short	t_flags;
   53: #define	TF_ACKNOW	0x0001		/* ack peer immediately */
   54: #define	TF_DELACK	0x0002		/* ack, but try to delay it */
   55: #define	TF_NODELAY	0x0004		/* don't delay packets to coalesce */
   56: #define	TF_NOOPT	0x0008		/* don't use tcp options */
   57: #define	TF_SENTFIN	0x0010		/* have sent FIN */
   58: #define	TF_REQ_SCALE	0x0020		/* have/will request window scaling */
   59: #define	TF_RCVD_SCALE	0x0040		/* other side has requested scaling */
   60: #define	TF_REQ_TSTMP	0x0080		/* have/will request timestamps */
   61: #define	TF_RCVD_TSTMP	0x0100		/* a timestamp was received in SYN */
   62: #define	TF_SACK_PERMIT	0x0200		/* other side said I could SACK */
   63: 
   64: 	/* Make it static  for now */
   65: /*	struct	tcpiphdr *t_template;	/ * skeletal packet for transmit */
   66: 	struct	tcpiphdr t_template;
   67: 
   68: 	struct	socket *t_socket;		/* back pointer to socket */
   69: /*
   70:  * The following fields are used as in the protocol specification.
   71:  * See RFC783, Dec. 1981, page 21.
   72:  */
   73: /* send sequence variables */
   74: 	tcp_seq	snd_una;		/* send unacknowledged */
   75: 	tcp_seq	snd_nxt;		/* send next */
   76: 	tcp_seq	snd_up;			/* send urgent pointer */
   77: 	tcp_seq	snd_wl1;		/* window update seg seq number */
   78: 	tcp_seq	snd_wl2;		/* window update seg ack number */
   79: 	tcp_seq	iss;			/* initial send sequence number */
   80: 	u_int32_t snd_wnd;		/* send window */
   81: /* receive sequence variables */
   82: 	u_int32_t rcv_wnd;		/* receive window */
   83: 	tcp_seq	rcv_nxt;		/* receive next */
   84: 	tcp_seq	rcv_up;			/* receive urgent pointer */
   85: 	tcp_seq	irs;			/* initial receive sequence number */
   86: /*
   87:  * Additional variables for this implementation.
   88:  */
   89: /* receive variables */
   90: 	tcp_seq	rcv_adv;		/* advertised window */
   91: /* retransmit variables */
   92: 	tcp_seq	snd_max;		/* highest sequence number sent;
   93: 					 * used to recognize retransmits
   94: 					 */
   95: /* congestion control (for slow start, source quench, retransmit after loss) */
   96: 	u_int32_t snd_cwnd;		/* congestion-controlled window */
   97: 	u_int32_t snd_ssthresh;		/* snd_cwnd size threshold for
   98: 					 * for slow start exponential to
   99: 					 * linear switch
  100: 					 */
  101: /*
  102:  * transmit timing stuff.  See below for scale of srtt and rttvar.
  103:  * "Variance" is actually smoothed difference.
  104:  */
  105: 	short	t_idle;			/* inactivity time */
  106: 	short	t_rtt;			/* round trip time */
  107: 	tcp_seq	t_rtseq;		/* sequence number being timed */
  108: 	short	t_srtt;			/* smoothed round-trip time */
  109: 	short	t_rttvar;		/* variance in round-trip time */
  110: 	u_short	t_rttmin;		/* minimum rtt allowed */
  111: 	u_int32_t max_sndwnd;		/* largest window peer has offered */
  112: 
  113: /* out-of-band data */
  114: 	char	t_oobflags;		/* have some */
  115: 	char	t_iobc;			/* input character */
  116: #define	TCPOOB_HAVEDATA	0x01
  117: #define	TCPOOB_HADDATA	0x02
  118: 	short	t_softerror;		/* possible error not yet reported */
  119: 
  120: /* RFC 1323 variables */
  121: 	u_char	snd_scale;		/* window scaling for send window */
  122: 	u_char	rcv_scale;		/* window scaling for recv window */
  123: 	u_char	request_r_scale;	/* pending window scaling */
  124: 	u_char	requested_s_scale;
  125: 	u_int32_t	ts_recent;		/* timestamp echo data */
  126: 	u_int32_t	ts_recent_age;		/* when last updated */
  127: 	tcp_seq	last_ack_sent;
  128: 
  129: };
  130: 
  131: #define	sototcpcb(so)	((so)->so_tcpcb)
  132: 
  133: /*
  134:  * The smoothed round-trip time and estimated variance
  135:  * are stored as fixed point numbers scaled by the values below.
  136:  * For convenience, these scales are also used in smoothing the average
  137:  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
  138:  * With these scales, srtt has 3 bits to the right of the binary point,
  139:  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
  140:  * binary point, and is smoothed with an ALPHA of 0.75.
  141:  */
  142: #define	TCP_RTT_SCALE		8	/* multiplier for srtt; 3 bits frac. */
  143: #define	TCP_RTT_SHIFT		3	/* shift for srtt; 3 bits frac. */
  144: #define	TCP_RTTVAR_SCALE	4	/* multiplier for rttvar; 2 bits */
  145: #define	TCP_RTTVAR_SHIFT	2	/* multiplier for rttvar; 2 bits */
  146: 
  147: /*
  148:  * The initial retransmission should happen at rtt + 4 * rttvar.
  149:  * Because of the way we do the smoothing, srtt and rttvar
  150:  * will each average +1/2 tick of bias.  When we compute
  151:  * the retransmit timer, we want 1/2 tick of rounding and
  152:  * 1 extra tick because of +-1/2 tick uncertainty in the
  153:  * firing of the timer.  The bias will give us exactly the
  154:  * 1.5 tick we need.  But, because the bias is
  155:  * statistical, we have to test that we don't drop below
  156:  * the minimum feasible timer (which is 2 ticks).
  157:  * This macro assumes that the value of TCP_RTTVAR_SCALE
  158:  * is the same as the multiplier for rttvar.
  159:  */
  160: #define	TCP_REXMTVAL(tp) \
  161: 	(((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
  162: 
  163: #ifdef LOG_ENABLED
  164: /*
  165:  * TCP statistics.
  166:  * Many of these should be kept per connection,
  167:  * but that's inconvenient at the moment.
  168:  */
  169: struct tcpstat {
  170: 	u_long	tcps_connattempt;	/* connections initiated */
  171: 	u_long	tcps_accepts;		/* connections accepted */
  172: 	u_long	tcps_connects;		/* connections established */
  173: 	u_long	tcps_drops;		/* connections dropped */
  174: 	u_long	tcps_conndrops;		/* embryonic connections dropped */
  175: 	u_long	tcps_closed;		/* conn. closed (includes drops) */
  176: 	u_long	tcps_segstimed;		/* segs where we tried to get rtt */
  177: 	u_long	tcps_rttupdated;	/* times we succeeded */
  178: 	u_long	tcps_delack;		/* delayed acks sent */
  179: 	u_long	tcps_timeoutdrop;	/* conn. dropped in rxmt timeout */
  180: 	u_long	tcps_rexmttimeo;	/* retransmit timeouts */
  181: 	u_long	tcps_persisttimeo;	/* persist timeouts */
  182: 	u_long	tcps_keeptimeo;		/* keepalive timeouts */
  183: 	u_long	tcps_keepprobe;		/* keepalive probes sent */
  184: 	u_long	tcps_keepdrops;		/* connections dropped in keepalive */
  185: 
  186: 	u_long	tcps_sndtotal;		/* total packets sent */
  187: 	u_long	tcps_sndpack;		/* data packets sent */
  188: 	u_long	tcps_sndbyte;		/* data bytes sent */
  189: 	u_long	tcps_sndrexmitpack;	/* data packets retransmitted */
  190: 	u_long	tcps_sndrexmitbyte;	/* data bytes retransmitted */
  191: 	u_long	tcps_sndacks;		/* ack-only packets sent */
  192: 	u_long	tcps_sndprobe;		/* window probes sent */
  193: 	u_long	tcps_sndurg;		/* packets sent with URG only */
  194: 	u_long	tcps_sndwinup;		/* window update-only packets sent */
  195: 	u_long	tcps_sndctrl;		/* control (SYN|FIN|RST) packets sent */
  196: 
  197: 	u_long	tcps_rcvtotal;		/* total packets received */
  198: 	u_long	tcps_rcvpack;		/* packets received in sequence */
  199: 	u_long	tcps_rcvbyte;		/* bytes received in sequence */
  200: 	u_long	tcps_rcvbadsum;		/* packets received with ccksum errs */
  201: 	u_long	tcps_rcvbadoff;		/* packets received with bad offset */
  202: /*	u_long	tcps_rcvshort;	*/	/* packets received too short */
  203: 	u_long	tcps_rcvduppack;	/* duplicate-only packets received */
  204: 	u_long	tcps_rcvdupbyte;	/* duplicate-only bytes received */
  205: 	u_long	tcps_rcvpartduppack;	/* packets with some duplicate data */
  206: 	u_long	tcps_rcvpartdupbyte;	/* dup. bytes in part-dup. packets */
  207: 	u_long	tcps_rcvoopack;		/* out-of-order packets received */
  208: 	u_long	tcps_rcvoobyte;		/* out-of-order bytes received */
  209: 	u_long	tcps_rcvpackafterwin;	/* packets with data after window */
  210: 	u_long	tcps_rcvbyteafterwin;	/* bytes rcvd after window */
  211: 	u_long	tcps_rcvafterclose;	/* packets rcvd after "close" */
  212: 	u_long	tcps_rcvwinprobe;	/* rcvd window probe packets */
  213: 	u_long	tcps_rcvdupack;		/* rcvd duplicate acks */
  214: 	u_long	tcps_rcvacktoomuch;	/* rcvd acks for unsent data */
  215: 	u_long	tcps_rcvackpack;	/* rcvd ack packets */
  216: 	u_long	tcps_rcvackbyte;	/* bytes acked by rcvd acks */
  217: 	u_long	tcps_rcvwinupd;		/* rcvd window update packets */
  218: /*	u_long	tcps_pawsdrop;	*/	/* segments dropped due to PAWS */
  219: 	u_long	tcps_predack;		/* times hdr predict ok for acks */
  220: 	u_long	tcps_preddat;		/* times hdr predict ok for data pkts */
  221: 	u_long	tcps_socachemiss;	/* tcp_last_so misses */
  222: 	u_long	tcps_didnuttin;		/* Times tcp_output didn't do anything XXX */
  223: };
  224: 
  225: extern struct	tcpstat tcpstat;	/* tcp statistics */
  226: #endif
  227: 
  228: extern u_int32_t	tcp_now;		/* for RFC 1323 timestamps */
  229: 
  230: #endif

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