/* $NetBSD: tcp_var.h,v 1.33 1998/01/05 10:32:14 thorpej Exp $ */ /* * 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 */ /* * Kernel variables for tcp. */ /* * Tcp control block, one per tcp; fields: */ struct tcpcb { struct ipqehead segq; /* sequencing queue */ short t_state; /* state of this connection */ short t_timer[TCPT_NTIMERS]; /* tcp timers */ short t_rxtshift; /* log(2) of rexmt exp. backoff */ short t_rxtcur; /* current retransmit value */ short t_dupacks; /* consecutive dup acks recd */ u_short t_peermss; /* peer's maximum segment size */ u_short t_ourmss; /* our's maximum segment size */ u_short t_segsz; /* current segment size in use */ char t_force; /* 1 if forcing out a byte */ u_short 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 */ struct tcpiphdr *t_template; /* skeletal packet for transmit */ struct inpcb *t_inpcb; /* back pointer to internet pcb */ LIST_ENTRY(tcpcb) t_delack; /* delayed ACK queue */ /* * 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 threshhold for * for slow start exponential to * linear switch */ /* * transmit timing stuff. See below for scale of srtt and rttvar. * "Variance" is actually smoothed difference. */ short t_idle; /* inactivity time */ short t_rtt; /* round trip time */ tcp_seq t_rtseq; /* sequence number being timed */ short t_srtt; /* smoothed round-trip time */ short t_rttvar; /* variance in round-trip time */ short 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 short 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_int32_t ts_recent; /* timestamp echo data */ u_int32_t ts_recent_age; /* when last updated */ tcp_seq last_ack_sent; /* TUBA stuff */ caddr_t t_tuba_pcb; /* next level down pcb for TCP over z */ }; /* * Queue for delayed ACK processing. */ LIST_HEAD(tcp_delack_head, tcpcb); #ifdef _KERNEL extern struct tcp_delack_head tcp_delacks; #define TCP_SET_DELACK(tp) \ do { \ if (((tp)->t_flags & TF_DELACK) == 0) { \ (tp)->t_flags |= TF_DELACK; \ LIST_INSERT_HEAD(&tcp_delacks, (tp), t_delack); \ } \ } while (0) #define TCP_CLEAR_DELACK(tp) \ do { \ if ((tp)->t_flags & TF_DELACK) { \ (tp)->t_flags &= ~TF_DELACK; \ LIST_REMOVE((tp), t_delack); \ } \ } while (0) #endif /* _KERNEL */ /* * Handy way of passing around TCP option info. */ struct tcp_opt_info { int ts_present; u_int32_t ts_val; u_int32_t ts_ecr; u_int16_t maxseg; }; /* * This structure should not exceed 32 bytes. * XXX On the Alpha, it's already 36-bytes, which rounds to 40. * XXX Need to eliminate the pointer. * * XXX We've blown 32 bytes on non-Alpha systems, too, since we're * XXX storing the maxseg we advertised to the peer. Should we * XXX create another malloc bucket? Should we care? */ struct syn_cache { struct syn_cache *sc_next; u_int32_t sc_tstmp : 1, sc_hash : 31; struct in_addr sc_src; struct in_addr sc_dst; tcp_seq sc_irs; tcp_seq sc_iss; u_int16_t sc_sport; u_int16_t sc_dport; u_int16_t sc_peermaxseg; u_int16_t sc_ourmaxseg; u_int8_t sc_timer; u_int8_t sc_request_r_scale : 4, sc_requested_s_scale : 4; }; struct syn_cache_head { struct syn_cache *sch_first; /* First entry in the bucket */ struct syn_cache *sch_last; /* Last entry in the bucket */ struct syn_cache_head *sch_headq; /* The next non-empty bucket */ int16_t sch_timer_sum; /* Total time in this bucket */ u_int16_t sch_length; /* @ # elements in bucket */ }; #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_SHIFT 3 /* shift for srtt; 3 bits frac. */ #define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */ /* * 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 macro assumes that the value of 1<t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) >> 2) #ifdef _KERNEL /* * Compute the initial window for slow start. */ extern int tcp_init_win; #define TCP_INITIAL_WINDOW(segsz) \ ((tcp_init_win == 0) ? (min(4 * (segsz), max(2 * (segsz), 4380))) : \ ((segsz) * tcp_init_win)) #endif /* _KERNEL */ /* * 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_persistdrops; /* connections dropped in persist */ u_long tcps_connsdrained; /* connections drained due to memory shortage */ 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_rcvmemdrop; /* packets dropped for lack of memory */ 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_pcbhashmiss; /* input packets missing pcb hash */ u_long tcps_noport; /* no socket on port */ u_long tcps_badsyn; /* received ack for which we have no SYN in compressed state */ /* These statistics deal with the SYN cache. */ u_long tcps_sc_added; /* # of entries added */ u_long tcps_sc_completed; /* # of connections completed */ u_long tcps_sc_timed_out; /* # of entries timed out */ u_long tcps_sc_overflowed; /* # dropped due to overflow */ u_long tcps_sc_reset; /* # dropped due to RST */ u_long tcps_sc_unreach; /* # dropped due to ICMP unreach */ u_long tcps_sc_bucketoverflow; /* # dropped due to bucket overflow */ u_long tcps_sc_aborted; /* # of entries aborted (no mem) */ u_long tcps_sc_dupesyn; /* # of duplicate SYNs received */ u_long tcps_sc_dropped; /* # of SYNs dropped (no route/mem) */ u_long tcps_sc_collisions; /* # of hash collisions */ }; /* * Names for TCP sysctl objects. */ #define TCPCTL_RFC1323 1 /* RFC1323 timestamps/scaling */ #define TCPCTL_SENDSPACE 2 /* default send buffer */ #define TCPCTL_RECVSPACE 3 /* default recv buffer */ #define TCPCTL_MSSDFLT 4 /* default seg size */ #define TCPCTL_SYN_CACHE_LIMIT 5 /* max size of comp. state engine */ #define TCPCTL_SYN_BUCKET_LIMIT 6 /* max size of hash bucket */ #define TCPCTL_SYN_CACHE_INTER 7 /* interval of comp. state timer */ #define TCPCTL_INIT_WIN 8 /* initial window */ #define TCPCTL_MAXID 9 #define TCPCTL_NAMES { \ { 0, 0 }, \ { "rfc1323", CTLTYPE_INT }, \ { "sendspace", CTLTYPE_INT }, \ { "recvspace", CTLTYPE_INT }, \ { "mssdflt", CTLTYPE_INT }, \ { "syn_cache_limit", CTLTYPE_INT }, \ { "syn_bucket_limit", CTLTYPE_INT }, \ { "syn_cache_interval", CTLTYPE_INT },\ { "init_win", CTLTYPE_INT }, \ } #ifdef _KERNEL struct inpcbtable tcbtable; /* head of queue of active tcpcb's */ struct tcpstat tcpstat; /* tcp statistics */ u_int32_t tcp_now; /* for RFC 1323 timestamps */ extern int tcp_do_rfc1323; /* enabled/disabled? */ extern int tcp_mssdflt; /* default seg size */ extern int tcp_init_win; /* initial window */ extern int tcp_syn_cache_limit; /* max entries for compressed state engine */ extern int tcp_syn_bucket_limit;/* max entries per hash bucket */ extern int tcp_syn_cache_interval; /* compressed state timer */ extern int tcp_syn_cache_size; extern int tcp_syn_cache_timeo; extern struct syn_cache_head tcp_syn_cache[], *tcp_syn_cache_first; extern u_long syn_cache_count; int tcp_attach __P((struct socket *)); void tcp_canceltimers __P((struct tcpcb *)); struct tcpcb * tcp_close __P((struct tcpcb *)); void *tcp_ctlinput __P((int, struct sockaddr *, void *)); int tcp_ctloutput __P((int, struct socket *, int, int, struct mbuf **)); struct tcpcb * tcp_disconnect __P((struct tcpcb *)); struct tcpcb * tcp_drop __P((struct tcpcb *, int)); void tcp_dooptions __P((struct tcpcb *, u_char *, int, struct tcpiphdr *, struct tcp_opt_info *)); void tcp_drain __P((void)); void tcp_established __P((struct tcpcb *)); void tcp_fasttimo __P((void)); void tcp_init __P((void)); void tcp_input __P((struct mbuf *, ...)); int tcp_mss_to_advertise __P((const struct tcpcb *)); void tcp_mss_from_peer __P((struct tcpcb *, int)); void tcp_mtudisc __P((struct inpcb *, int)); struct tcpcb * tcp_newtcpcb __P((struct inpcb *)); void tcp_notify __P((struct inpcb *, int)); int tcp_output __P((struct tcpcb *)); void tcp_pulloutofband __P((struct socket *, struct tcpiphdr *, struct mbuf *)); void tcp_quench __P((struct inpcb *, int)); int tcp_reass __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *)); int tcp_respond __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *, tcp_seq, tcp_seq, int)); void tcp_rmx_rtt __P((struct tcpcb *)); void tcp_setpersist __P((struct tcpcb *)); void tcp_slowtimo __P((void)); struct tcpiphdr * tcp_template __P((struct tcpcb *)); struct tcpcb * tcp_timers __P((struct tcpcb *, int)); void tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int)); struct tcpcb * tcp_usrclosed __P((struct tcpcb *)); int tcp_sysctl __P((int *, u_int, void *, size_t *, void *, size_t)); int tcp_usrreq __P((struct socket *, int, struct mbuf *, struct mbuf *, struct mbuf *, struct proc *)); void tcp_xmit_timer __P((struct tcpcb *, int)); tcp_seq tcp_new_iss __P((void *, u_long, tcp_seq)); int syn_cache_add __P((struct socket *, struct mbuf *, u_char *, int, struct tcp_opt_info *)); void syn_cache_unreach __P((struct ip *, struct tcphdr *)); struct socket * syn_cache_get __P((struct socket *so, struct mbuf *)); void syn_cache_insert __P((struct syn_cache *, struct syn_cache ***, struct syn_cache_head **)); struct syn_cache * syn_cache_lookup __P((struct tcpiphdr *, struct syn_cache ***, struct syn_cache_head **)); void syn_cache_reset __P((struct tcpiphdr *)); int syn_cache_respond __P((struct syn_cache *, struct mbuf *, register struct tcpiphdr *, long, u_long)); void syn_cache_timer __P((int)); #endif