#define RCSTCPHDR "$Header: tcp.h,v 1.19 85/07/31 09:33:34 walsh Exp $"
struct th
{ /* tcp header (fits over ip header) */
struct th
*t_next
; /* -> next tcp on rcv chain */
struct th
*t_prev
; /* -> prev tcp on rcv chain */
u_char t_x1
; /* (unused) */ u_char t_pr
; /* protocol */ u_short t_len
; /* seg length */ struct in_addr t_s
; /* source internet address */
struct in_addr t_d
; /* destination internet address */
u_short t_src
; /* source port */ u_short t_dst
; /* destination port */ sequence t_seq
; /* sequence number */ sequence t_ackno
; /* acknowledgement number */#define t_end(x) (x->t_seq + x->t_len - 1)
t_off
:4; /* data offset */#define T_FIN 0x01 /* fin flag */
#define T_SYN 0x02 /* syn flag */
#define T_RST 0x04 /* reset flag */
#define T_PUSH 0x08 /* push flag */
#define T_ACK 0x10 /* ack flag */
#define T_URG 0x20 /* urgent flag */
u_short t_win
; /* window */ u_short t_sum
; /* checksum */ u_short t_urp
; /* urgent pointer */#define TCP_END_OPT 0 /* end of option list */
#define TCP_NOP_OPT 1 /* nop option */
#define TCP_MAXSEG_OPT 2 /* maximum segment size option */
#define TCP_MAXSEG_OPTLEN 4 /* max seg option length */
#define TCP_MAXSEG_OPTHDR ((TCP_MAXSEG_OPT<<8)|TCP_MAXSEG_OPTLEN)
typedef u_char tcptimerval
; /* in 0.5 second units */
#define MAX_TCPTIMERVAL 255
struct tcpcb
{ /* tcp control block */
/* where store data until gets to socket */
struct th
*t_rcv_next
; /* -> first el on rcv queue */
struct th
*t_rcv_prev
; /* -> last el on rcv queue */
int t_rcv_len
; /* length of rcv queue */
struct inpcb
*t_in_pcb
; /* -> in_pcb */
struct mbuf
*t_rcv_unack
; /* -> unacked message queue */
/* ### how about a tail pointer */
/* sequence number variables */
sequence iss
; /* initial send seq # */ sequence irs
; /* initial recv seq # */ sequence rcv_urp
; /* rcv urgent pointer */ sequence rcv_nxt
; /* next contiguous seq # to rcv */ sequence seq_fin
; /* seq # of FIN sent */ sequence snd_end
; /* send eol pointer. end of PUSH */ sequence snd_urp
; /* snd urgent pointer. end of URG */ sequence snd_lst
; /* seq # of last datum to send */ sequence snd_nxt
; /* seq # of next datum to send */ sequence snd_una
; /* seq # of first unacked datum */ sequence snd_wl
; /* seq # of last sent window */ sequence snd_hi
; /* highest seq # we sent */ sequence t_xmt_val
; /* seq # measuring round trip time of */ /* various flags and state variables
* At one time booleans were a bitfield, but since are using mbufs,
* have space and is quicker to test/set byte than bit.
char ack_due
; /* must we send ACK */
char cancelled
; /* retransmit timer cancelled */
char dropped_txt
; /* dropped incoming data */
char fin_rcvd
; /* FIN received */
char force_one
; /* force sending of one byte */
char new_window
; /* received new window size */
char rexmt
; /* this msg is a retransmission */
char snd_fin
; /* FIN should be sent */
char snd_rst
; /* RST should be sent */
char snd_urg
; /* urgent data to send */
char syn_acked
; /* SYN has been ACKed */
char syn_rcvd
; /* SYN has been received */
char usr_closed
; /* user has closed connection */
char waited_2_ml
; /* wait time for FIN ACK is up */
char usr_abort
; /* user has closed and does not expect
to receive any more data */
char sent_zero
; /* sent zero window */
char force_ack
; /* force sending of ack */
char t_noactprobe
; /* see tcp_newtcpcb() */
u_short snd_wnd
; /* window he advertised */ short t_maxseg
; /* max seg size peer can handle */
u_short t_maxfrag
; /* max IP frag size received */ u_short t_olddata
; /* useless rexmts received */ u_short t_preproc
; /* #segs out of window rcvd */ u_short t_rxtct
; /* # of retransmissions */ u_char t_state
; /* state of this connection */ tcptimerval t_srtt
; /* smoothed round trip time */ * Not used to limit t_srtt, but to estimate limits/values for the
* timers given the rxmitime = 1.5 srtt, and rxmitime doubles for
* This is the srtt on our slowest network connection.
#define TCP_tvMAXSRTT 20 /* 10 seconds */
tcptimerval t_rxmitime
; /* current rexmt time */ * Allow some slop for the maximum in case the network experiences
* a temporary peak loading
#define TCP_tvRXMAX ((3 * TCP_tvMAXSRTT) / 2)
tcptimerval t_itimeo
; /* init timeout value */ /* by default, try 3+ syns to get to the other side */
#define TCP_tvINIT (TCP_tvMAXSRTT + 3 * TCP_tvRXMAX)
tcptimerval t_rttltimeo
; /* rxmit took too long timeout value */ /* by default, try 4+ retransmissions before warn user */
#define TCP_tvRTTL (TCP_tvMAXSRTT + 4 * TCP_tvRXMAX)
tcptimerval t_noact
; /* no activity timeout value (mins.) */#define TCP_tvNOACT 10 /* internal no activity timeout (min) */
tcptimerval t_timers
[NTIMERS
];/* the timers */ #define TCP_tvMINPERSIST 10
#define TCP_tvMAXPERSIST 90
#define TCP_tv2ML 40 /* 2*maximum packet lifetime */
struct mbuf
*oob_data
; /* for 4.2 implementation of urgent */
sequence rcv_urpend
; /* (out-of-band) data */ short sws_qff
; /* silly window syndrome and icmp
* source quench fudge factor */
sequence lastack
; /* with force_ack, for TDELACK */ u_short rcv_wnd
; /* window we advertised */ struct th
*t_template
; /* for send_pkt() */
#if TCP_tvRXMAX > MAX_TCPTIMERVAL
#if TCP_tvINIT > MAX_TCPTIMERVAL
#if TCP_tvRTTL > MAX_TCPTIMERVAL
struct t_debug
{ /* tcp debugging record */
char t_oldstate
; /* old state */
char t_input
; /* input */
char t_timer
; /* timer id */
char t_newstate
; /* new state */
struct tcpcb t_tcb
; /* -> tcb */
struct th t_hdr
; /* valid iff input is INRECV */
#define DB_PER_CHUNK(x) (((x)/sizeof(struct t_debug)) * sizeof(struct t_debug))
#define TDBLEN DB_PER_CHUNK(MLEN)
#define TCDBLEN DB_PER_CHUNK(CLBYTES)
#define t_total t_in.in_total
#define t_badsum t_in.in_badsum
#define t_tooshort t_in.in_tooshort
int t_badsegs
; /* #bad tcp segments (to which we send RST) */
int t_unack
; /* #tcp segs placed on rcv_unack */
int t_retransmit
; /* #retransmissions we sent */
int t_ackonly
; /* #send_pkt just to send ack, no data */
/* size of TCP leader (bytes) */
#define TCPSIZE (sizeof(struct th)-sizeof(struct ip))
* max size of TCP/IP leader. If start using options on tcp connections,
* increase TCPIPMAX accordingly.
#define TCPIPMAX sizeof(struct th)
/* initial maximum segment size */
#define TCPMAXSND (IPMAX - TCPIPMAX)
/* get the tcpcb from the inpcb */
#define inptotcpcb(inp) ((struct tcpcb *)((inp)->inp_ppcb))
#define sototcpcb(so) (inptotcpcb((struct inpcb *)((so)->so_pcb)))
#define tcpcbtoso(tp) ((tp)->t_in_pcb->inp_socket)
#define TCP_CTL 1 /* send/receive control call */
#define TCP_DATA 0 /* send/receive data call */
#define T_LINGERTIME 120 /* two minutes of linger */
/* tcp machine predicates */
* Is there unacked data on this TCP connection?
#define is_unacked(t) (SEQ_LT((t)->snd_una, (t)->snd_hi))
#define ack_fin(x, y) (SEQ_GT((x)->seq_fin, (x)->iss) && \
SEQ_GT((y)->t_ackno, (x)->seq_fin))
/* receive buffer empty */
#define rcv_empty(x) ((x)->usr_abort || \
((x)->t_in_pcb->inp_socket->so_rcv.sb_cc == 0 && \
(x)->t_rcv_next == (struct th *)(x)))
#define t_cancel(tp, timer) ((tp)->t_timers[timer] = 0)
char *tcp_conn_used(); /* see note about return value */
struct th
*tcp_template();
* If we have many incarnations of a connection in a time period, do not
* want the sequence number space of them to overlap and have packets for
* one be mistaken as from another.
* Assume max throughput of 1Mbit/sec == 125kbyte/sec for TCP
#define ISSINCR ((125*1024) / PR_SLOWHZ)
#define TCP_RESERVED 1023 /* <= for root only */
#define TCP_USERRESERVED 5000 /* reserved for applications */
#define TCP_MAXPORT 0xffff
extern struct tcp_stat tcpstat
;
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