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/*!\file netinet/tcp_var.h
* Internal TCP structures and statistics.
*/
/*
* Copyright (c) 1982, 1986, 1993, 1994, 1995
* The Regents of the University of California. 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
*
* @(#)tcp_var.h 8.4 (Berkeley) 5/24/95
* $Id: tcp_var.h,v 1.36 1996/09/13 23:54:03 pst Exp $
*/
#ifndef __NETINET_TCP_VAR_H
#define __NETINET_TCP_VAR_H
/*
* Kernel variables for tcp.
*/
#ifdef TCP_AUTO
/* AUTO_RCV_HITHRESH flush reassembly queue, drop incoming packets
*/
#define AUTO_RCV_HITHRESH (u_long)(0.95 * NMBCLUSTERS)
/* AUTO_RCV_LOWTHRESH drop incoming packets
*/
#define AUTO_RCV_LOWTHRESH (u_long)(0.9 * NMBCLUSTERS)
/* AUTO_SND_THRESH reduce so_snd.sb_hiwat by acked
*/
#define AUTO_SND_THRESH (u_long)(0.50 * NMBCLUSTERS)
#endif
#if defined(TCP_SACK) || defined(TCP_FACK)
#include <netinet/tcp_scor.h>
struct sackblock {
tcp_seq start;
tcp_seq end;
};
#endif
/*
* Tcp control block, one per tcp; fields:
*/
struct tcpcb {
struct tcpiphdr *seg_next; /* sequencing queue */
struct tcpiphdr *seg_prev;
/* !! struct ipqehead segq; */ /* sequencing queue */
int t_state; /* state of this connection */
int t_timer[TCPT_NTIMERS]; /* tcp timers */
int t_rxtshift; /* log(2) of rexmt exp. backoff */
int t_rxtcur; /* current retransmit value */
#ifdef TCP_FACK
short t_padd; /* filler to preserve alignment */
#else
short t_dupacks; /* consecutive dup acks recd */
#endif
u_int t_maxseg; /* maximum segment size */
u_int t_maxopd; /* mss plus options */
int t_force; /* 1 if forcing out a byte */
u_int t_flags;
#define TF_ACKNOW 0x0001 /* ack peer immediately */
#define TF_DELACK 0x0002 /* ack, but try to delay it */
#define TF_NODELAY 0x0004 /* don't delay packets to coalesce */
#define TF_NOOPT 0x0008 /* don't use tcp options */
#define TF_SENTFIN 0x0010 /* have sent FIN */
#define TF_REQ_SCALE 0x0020 /* have/will request window scaling */
#define TF_RCVD_SCALE 0x0040 /* other side has requested scaling */
#define TF_REQ_TSTMP 0x0080 /* have/will request timestamps */
#define TF_RCVD_TSTMP 0x0100 /* a timestamp was received in SYN */
#define TF_SACK_PERMIT 0x0200 /* other side said I could SACK */
#define TF_NEEDSYN 0x0400 /* send SYN (implicit state) */
#define TF_NEEDFIN 0x0800 /* send FIN (implicit state) */
#define TF_NOPUSH 0x1000 /* don't push */
#define TF_REQ_CC 0x2000 /* have/will request CC */
#define TF_RCVD_CC 0x4000 /* a CC was received in SYN */
#define TF_SENDCCNEW 0x8000 /* send CCnew instead of CC in SYN */
struct tcpiphdr *t_template; /* skeletal packet for transmit */
struct inpcb *t_inpcb; /* back pointer to internet pcb */
/*
* The following fields are used as in the protocol specification.
* See RFC783, Dec. 1981, page 21.
*/
/* send sequence variables */
tcp_seq snd_una; /* send unacknowledged */
tcp_seq snd_nxt; /* send next */
tcp_seq snd_up; /* send urgent pointer */
tcp_seq snd_wl1; /* window update seg seq number */
tcp_seq snd_wl2; /* window update seg ack number */
tcp_seq iss; /* initial send sequence number */
u_long snd_wnd; /* send window */
/* receive sequence variables */
u_long rcv_wnd; /* receive window */
tcp_seq rcv_nxt; /* receive next */
tcp_seq rcv_up; /* receive urgent pointer */
tcp_seq irs; /* initial receive sequence number */
/*
* Additional variables for this implementation.
*/
/* receive variables */
tcp_seq rcv_adv; /* advertised window */
/* retransmit variables */
tcp_seq snd_max; /* highest sequence number sent;
* used to recognize retransmits
*/
/* congestion control (for slow start, source quench, retransmit after loss) */
u_long snd_cwnd; /* congestion-controlled window */
u_long snd_ssthresh; /* snd_cwnd size threshold for
* for slow start exponential to
* linear switch
*/
/*
* transmit timing stuff. See below for scale of srtt and rttvar.
* "Variance" is actually smoothed difference.
*/
u_int t_idle; /* inactivity time */
int t_rtt; /* round trip time */
tcp_seq t_rtseq; /* sequence number being timed */
int t_srtt; /* smoothed round-trip time */
int t_rttvar; /* variance in round-trip time */
u_int t_rttmin; /* minimum rtt allowed */
u_long max_sndwnd; /* largest window peer has offered */
/* out-of-band data */
char t_oobflags; /* have some */
char t_iobc; /* input character */
#define TCPOOB_HAVEDATA 0x01
#define TCPOOB_HADDATA 0x02
int t_softerror; /* possible error not yet reported */
/* RFC 1323 variables */
u_char snd_scale; /* window scaling for send window */
u_char rcv_scale; /* window scaling for recv window */
u_char request_r_scale; /* pending window scaling */
u_char requested_s_scale;
u_long ts_recent; /* timestamp echo data */
u_long ts_recent_age; /* when last updated */
tcp_seq last_ack_sent;
/* RFC 1644 variables */
tcp_cc cc_send; /* send connection count */
tcp_cc cc_recv; /* receive connection count */
u_long t_duration; /* connection duration */
/* TUBA stuff */
caddr_t t_tuba_pcb; /* next level down pcb for TCP over z */
/* More RTT stuff */
u_long t_rttupdated; /* number of times rtt sampled */
#if defined(TCP_FACK) || defined(TCP_AUTO)
u_short t_alt_flags; /* experimental flags */
#define TAF_SACK_SEEN 0x0001 /* other side can send SACKs */
#define TAF_RECOVERY 0x0002 /* We are recovering from a lost segment */
#define TAF_RATEHALF 0x0004 /* We are reducing the window during recovery */
#define TAF_REPAIRED 0x0008 /* We have retransmitted something */
#define TAF_WHOLD 0x0010 /* we are in the window hold state */
#define TAF_TOGGLE 0x0020 /* divide by 2 toggle */
#define TAF_AUTO_OFF 0x0040 /* autotuning is forced off */
#endif
#if defined(TCP_SACK) || defined(TCP_FACK)
#define SACK_LIST_LEN 10
/* Needed for SACK and FACK: */
struct sackblock sack_list[SACK_LIST_LEN]; /* Hack, keep 5 most recent SACKs */
struct scoreboard scrb;
int snd_retran_data;
tcp_seq recover;
#endif
#ifdef TCP_SACK
int pipe;
#endif
#ifdef TCP_FACK
tcp_seq snd_fack;
#define TCP_FACK_REXMTTHRESH 3 /* number of SACKs before retransmitting a block */
u_long lothresh; /* recovery window floor */
u_long hithresh; /* maximum window following recovery */
#endif
};
/*
* Structure to hold TCP options that are only used during segment
* processing (in tcp_input), but not held in the tcpcb.
* It's basically used to reduce the number of parameters
* to tcp_dooptions.
*/
struct tcpopt {
u_long to_flag; /* which options are present */
#define TOF_TS 0x0001 /* timestamp */
#define TOF_CC 0x0002 /* CC and CCnew are exclusive */
#define TOF_CCNEW 0x0004
#define TOF_CCECHO 0x0008
u_long to_tsval;
u_long to_tsecr;
tcp_cc to_cc; /* holds CC or CCnew */
tcp_cc to_ccecho;
};
/*
* The TAO cache entry which is stored in the protocol family specific
* portion of the route metrics.
*/
struct rmxp_tao {
tcp_cc tao_cc; /* latest CC in valid SYN */
tcp_cc tao_ccsent; /* latest CC sent to peer */
u_short tao_mssopt; /* peer's cached MSS */
#ifdef notyet
u_short tao_flags; /* cache status flags */
#define TAOF_DONT 0x0001 /* peer doesn't understand rfc1644 */
#define TAOF_OK 0x0002 /* peer does understand rfc1644 */
#define TAOF_UNDEF 0 /* we don't know yet */
#endif /* notyet */
};
#define rmx_taop(r) ((struct rmxp_tao *)(r).rmx_filler)
#define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
#define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
/*
* The smoothed round-trip time and estimated variance
* are stored as fixed point numbers scaled by the values below.
* For convenience, these scales are also used in smoothing the average
* (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
* With these scales, srtt has 3 bits to the right of the binary point,
* and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
* binary point, and is smoothed with an ALPHA of 0.75.
*/
#define TCP_RTT_SCALE 32 /* multiplier for srtt; 3 bits frac. */
#define TCP_RTT_SHIFT 5 /* shift for srtt; 3 bits frac. */
#define TCP_RTTVAR_SCALE 16 /* multiplier for rttvar; 2 bits */
#define TCP_RTTVAR_SHIFT 4 /* shift for rttvar; 2 bits */
#define TCP_DELTA_SHIFT 2 /* see tcp_input.c */
/*
* The initial retransmission should happen at rtt + 4 * rttvar.
* Because of the way we do the smoothing, srtt and rttvar
* will each average +1/2 tick of bias. When we compute
* the retransmit timer, we want 1/2 tick of rounding and
* 1 extra tick because of +-1/2 tick uncertainty in the
* firing of the timer. The bias will give us exactly the
* 1.5 tick we need. But, because the bias is
* statistical, we have to test that we don't drop below
* the minimum feasible timer (which is 2 ticks).
* This version of the macro adapted from a paper by Lawrence
* Brakmo and Larry Peterson which outlines a problem caused
* by insufficient precision in the original implementation,
* which results in inappropriately large RTO values for very
* fast networks.
*/
#define TCP_REXMTVAL(tp) \
((((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT)) \
+ (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
/* XXX
* We want to avoid doing m_pullup on incoming packets but that
* means avoiding dtom on the tcp reassembly code. That in turn means
* keeping an mbuf pointer in the reassembly queue (since we might
* have a cluster). As a quick hack, the source & destination
* port numbers (which are no longer needed once we've located the
* tcpcb) are overlayed with an mbuf pointer.
*/
#define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t))
/*
* TCP statistics.
* Many of these should be kept per connection,
* but that's inconvenient at the moment.
*/
struct tcpstat {
u_long tcps_connattempt; /* connections initiated */
u_long tcps_accepts; /* connections accepted */
u_long tcps_connects; /* connections established */
u_long tcps_drops; /* connections dropped */
u_long tcps_conndrops; /* embryonic connections dropped */
u_long tcps_closed; /* conn. closed (includes drops) */
u_long tcps_segstimed; /* segs where we tried to get rtt */
u_long tcps_rttupdated; /* times we succeeded */
u_long tcps_delack; /* delayed acks sent */
u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
u_long tcps_rexmttimeo; /* retransmit timeouts */
u_long tcps_persisttimeo; /* persist timeouts */
u_long tcps_keeptimeo; /* keepalive timeouts */
u_long tcps_keepprobe; /* keepalive probes sent */
u_long tcps_keepdrops; /* connections dropped in keepalive */
u_long tcps_sndtotal; /* total packets sent */
u_long tcps_sndpack; /* data packets sent */
u_long tcps_sndbyte; /* data bytes sent */
u_long tcps_sndrexmitpack; /* data packets retransmitted */
u_long tcps_sndrexmitbyte; /* data bytes retransmitted */
u_long tcps_sndacks; /* ack-only packets sent */
u_long tcps_sndprobe; /* window probes sent */
u_long tcps_sndurg; /* packets sent with URG only */
u_long tcps_sndwinup; /* window update-only packets sent */
u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
u_long tcps_rcvtotal; /* total packets received */
u_long tcps_rcvpack; /* packets received in sequence */
u_long tcps_rcvbyte; /* bytes received in sequence */
u_long tcps_rcvbadsum; /* packets received with ccksum errs */
u_long tcps_rcvbadoff; /* packets received with bad offset */
u_long tcps_rcvshort; /* packets received too short */
u_long tcps_rcvduppack; /* duplicate-only packets received */
u_long tcps_rcvdupbyte; /* duplicate-only bytes received */
u_long tcps_rcvpartduppack; /* packets with some duplicate data */
u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
u_long tcps_rcvoopack; /* out-of-order packets received */
u_long tcps_rcvoobyte; /* out-of-order bytes received */
u_long tcps_rcvpackafterwin; /* packets with data after window */
u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */
u_long tcps_rcvafterclose; /* packets rcvd after "close" */
u_long tcps_rcvwinprobe; /* rcvd window probe packets */
u_long tcps_rcvdupack; /* rcvd duplicate acks */
u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */
u_long tcps_rcvackpack; /* rcvd ack packets */
u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */
u_long tcps_rcvwinupd; /* rcvd window update packets */
u_long tcps_pawsdrop; /* segments dropped due to PAWS */
u_long tcps_predack; /* times hdr predict ok for acks */
u_long tcps_preddat; /* times hdr predict ok for data pkts */
u_long tcps_pcbcachemiss;
u_long tcps_cachedrtt; /* times cached RTT in route updated */
u_long tcps_cachedrttvar; /* times cached rttvar updated */
u_long tcps_cachedssthresh; /* times cached ssthresh updated */
u_long tcps_usedrtt; /* times RTT initialized from route */
u_long tcps_usedrttvar; /* times RTTVAR initialized from rt */
u_long tcps_usedssthresh; /* times ssthresh initialized from rt*/
u_long tcps_persistdrop; /* timeout in persist state */
u_long tcps_badsyn; /* bogus SYN, e.g. premature ACK */
u_long tcps_mturesent; /* resends due to MTU discovery */
u_long tcps_listendrop; /* listen queue overflows */
#ifdef TCP_FACK
/* NOTE: This may break some programs that rely on this structure
* being fixed length.
*/
u_long tcps_fack_recovery; /* fack: recovery episodes */
u_long tcps_fack_sndpack; /* fack: data packets sent */
u_long tcps_fack_sndbyte; /* fack: data bytes sent */
u_long tcps_fack_sndrexmitpack;/* fack: data packets retransmitted */
u_long tcps_fack_sndrexmitbyte;/* fack: data bytes retransmitted */
#endif
};
/*
* Names for TCP sysctl objects
*/
#define TCPCTL_DO_RFC1323 1 /* use RFC-1323 extensions */
#define TCPCTL_DO_RFC1644 2 /* use RFC-1644 extensions */
#define TCPCTL_MSSDFLT 3 /* MSS default */
#define TCPCTL_STATS 4 /* statistics (read-only) */
#define TCPCTL_RTTDFLT 5 /* default RTT estimate */
#define TCPCTL_KEEPIDLE 6 /* keepalive idle timer */
#define TCPCTL_KEEPINTVL 7 /* interval to send keepalives */
#define TCPCTL_SENDSPACE 8 /* send buffer space */
#define TCPCTL_RECVSPACE 9 /* receive buffer space */
#define TCPCTL_KEEPINIT 10 /* receive buffer space */
#define TCPCTL_MAXID 11
#define TCPCTL_NAMES { \
{ 0, 0 }, \
{ "rfc1323", CTLTYPE_INT }, \
{ "rfc1644", CTLTYPE_INT }, \
{ "mssdflt", CTLTYPE_INT }, \
{ "stats", CTLTYPE_STRUCT }, \
{ "rttdflt", CTLTYPE_INT }, \
{ "keepidle", CTLTYPE_INT }, \
{ "keepintvl", CTLTYPE_INT }, \
{ "sendspace", CTLTYPE_INT }, \
{ "recvspace", CTLTYPE_INT }, \
{ "keepinit", CTLTYPE_INT }, \
}
#endif