+/* --------------- end of TCP config ---------------- */
+
+/*
+ * Kernel variables for tcp.
+ */
+
+/*
+ * Tcp control block, one per tcp; fields:
+ */
+struct tcpcb {
+ struct tcpiphdr *seg_next; /* sequencing queue */
+ struct tcpiphdr *seg_prev;
+ 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_maxseg; /* maximum segment size */
+ char t_force; /* 1 if forcing out a byte */
+ u_char t_flags;
+#define TF_ACKNOW 0x01 /* ack peer immediately */
+#define TF_DELACK 0x02 /* ack, but try to delay it */
+#define TF_NODELAY 0x04 /* don't delay packets to coalesce */
+#define TF_NOOPT 0x08 /* don't use tcp options */
+#define TF_SENTFIN 0x10 /* have sent FIN */
+ 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_short snd_wnd; /* send window */
+/* receive sequence variables */
+ u_short 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_short snd_cwnd; /* congestion-controlled window */
+ u_short snd_ssthresh; /* snd_cwnd size threshhold for
+ * for slow start exponential to
+ * linear switch */
+/*
+ * transmit timing stuff.
+ * srtt and rttvar are stored as fixed point; for convenience in smoothing,
+ * srtt has 3 bits to the right of the binary point, rttvar has 2.
+ * "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 */
+ u_short max_rcvd; /* most peer has sent into window */
+ u_short 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
+};
+
+#define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
+#define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
+
+/*
+ * TCP statistics.
+ * Many of these should be kept per connection,
+ * but that's inconvenient at the moment.
+ */
+struct tcpstat {
+#ifdef OLDSTAT
+ /*
+ * Declare statistics the same as in 4.3
+ * at the start of tcpstat (same size and
+ * position) for netstat.
+ */
+ int tcps_rcvbadsum;
+ int tcps_rcvbadoff;
+ int tcps_rcvshort;
+ int tcps_badsegs;
+ int tcps_unack;
+#define tcps_badsum tcps_rcvbadsum
+#define tcps_badoff tcps_rcvbadoff
+#define tcps_hdrops tcps_rcvshort
+
+#endif OLDSTAT
+#ifdef OLDSTAT
+ /*
+ * Declare statistics the same as in 4.3
+ * at the start of tcpstat (same size and
+ * position) for netstat.
+ */
+ int tcps_rcvbadsum;
+ int tcps_rcvbadoff;
+ int tcps_rcvshort;
+ int tcps_badsegs;
+ int tcps_unack;
+#define tcps_badsum tcps_rcvbadsum
+#define tcps_badoff tcps_rcvbadoff
+#define tcps_hdrops tcps_rcvshort
+
+#endif OLDSTAT
+ 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 */
+#ifndef OLDSTAT
+#ifndef OLDSTAT
+ 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 */