BBN-Vax-TCP/bbnnet-oct82/tcp.h
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 */
#ifdef mbb
short t_x0, t_x00; /* (for alignment) */
#endif mbb
u_char t_x1; /* (unused) */
u_char t_pr; /* protocol */
u_short t_len; /* seg length */
struct socket t_s; /* source internet address */
struct socket 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)
#ifndef mbb
u_char
t_x2:4, /* (unused) */
t_off:4; /* data offset */
#else
u_char
t_x21:2, /* (unused) */
t_off:4, /* data offset */
t_x2:4; /* (unused) */
#endif mbb
u_char t_flags;
#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 0x0402 /* max seg opt/len */
struct tcb { /* tcp control block */
/* various pointers */
struct th *t_rcv_next; /* -> first el on rcv queue */
struct th *t_rcv_prev; /* -> last el on rcv queue */
struct tcb *t_tcb_next; /* -> next tcb */
struct tcb *t_tcb_prev; /* -> prev tcb */
struct ucb *t_ucb; /* -> ucb */
struct mbuf *t_rcv_unack; /* -> unacked message queue */
char *t_opts; /* -> ip option string */
/* sequence number variables */
sequence iss; /* initial send seq # */
sequence irs; /* initial recv seq # */
sequence rcv_urp; /* rcv urgent pointer */
sequence rcv_nxt; /* next seq # to rcv */
sequence rcv_end; /* rcv eol pointer */
sequence seq_fin; /* seq # of FIN sent */
sequence snd_end; /* send eol pointer */
sequence snd_urp; /* snd urgent pointer */
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 # sent */
sequence t_rexmt_val; /* val saved in rexmt timer */
sequence t_rtl_val; /* val saved in rexmt too long timer */
sequence t_xmt_val; /* seq # sent when xmt timer started */
/* various flags and state variables */
#ifndef mbb
u_long
#else
u_short
#endif
ack_due:1, /* must we send ACK */
cancelled:1, /* retransmit timer cancelled */
dropped_txt:1, /* dropped incoming data */
fin_rcvd:1, /* FIN received */
force_one:1, /* force sending of one byte */
new_window:1, /* received new window size */
rexmt:1, /* this msg is a retransmission */
snd_fin:1, /* FIN should be sent */
snd_rst:1, /* RST should be sent */
snd_urg:1, /* urgent data to send */
syn_acked:1, /* SYN has been ACKed */
syn_rcvd:1, /* SYN has been received */
usr_closed:1, /* user has closed connection */
waited_2_ml:1, /* wait time for FIN ACK is up */
net_keep:1, /* don't free this net input */
usr_abort:1, /* user has closed and does not expect
to receive any more data */
sent_zero:1; /* sent zero window */
short snd_wnd; /* advertised window */
short t_maxseg; /* max seg size peer can handle */
u_short t_lport; /* local port */
u_short t_fport; /* foreign port */
u_char t_state; /* state of this connection */
u_char t_xmtime; /* current rexmt time */
u_char t_optlen; /* length of ip option string */
u_char t_timers[6]; /* timers */
u_char t_rxtct; /* # of retransmissions */
};
/* size of TCP leader (bytes) */
#define TCPSIZE (sizeof(struct th)-sizeof(struct ip))
/* max size of TCP/IP leader */
#define TCPIPMAX (sizeof(struct th) + IPMAXOPT)
/* initial maximum segment size */
#define TCPMAXSND (IPMAX - TCPIPMAX)
#define ISSINCR 128 /* increment for iss each second */
#define TCPROTO 6 /* TCP-4 protocol number */
#define T_2ML 20 /* 2*maximum packet lifetime */
#define T_PERS 5 /* persist time */
#define T_INIT 30 /* init too long timeout */
#define T_REXMT 2 /* base for retransmission time */
#define T_REXMTTL 30 /* retransmit too long timeout */
#define T_REMAX 30 /* maximum retransmission time */
#define TCP_ACTIVE 1 /* active open */
#define TCP_PASSIVE 0 /* passive open */
#define TCP_CTL 1 /* send/receive control call */
#define TCP_DATA 0 /* send/receive data call */
/* macros for sequence number comparison (32 bit modular arithmatic) */
#ifndef mbb
#define SEQ_LT(a,b) ((long)((a)-(b)) < 0)
#define SEQ_LEQ(a,b) ((long)((a)-(b)) <= 0)
#define SEQ_GT(a,b) ((long)((a)-(b)) > 0)
#define SEQ_GEQ(a,b) ((long)((a)-(b)) >= 0)
#define SEQ_EQ(a,b) ((a) == (b))
#define SEQ_NEQ(a,b) ((a) != (b))
#else
#define NBIT 8
#define BMASK 037777777777
#define SEQ_LT(a,b) ((((a)-(b)) << NBIT) < 0)
#define SEQ_LEQ(a,b) ((((a)-(b)) << NBIT) <= 0)
#define SEQ_GT(a,b) ((((a)-(b)) << NBIT) > 0)
#define SEQ_GEQ(a,b) ((((a)-(b)) << NBIT) >= 0)
#define SEQ_EQ(a,b) ((((a)-(b)) & BMASK) == 0)
#define SEQ_NEQ(a,b) ((((a)-(b)) & BMASK) != 0)
#endif
#define SEQ_MIN(a,b) (SEQ_LT((a),(b)) ? (a) : (b))
#define SEQ_MAX(a,b) (SEQ_GT((a),(b)) ? (a) : (b))
/* tcp machine predicates */
/* acceptable ACK */
#define ack_ok(x, y) (SEQ_LT(x->iss, y->t_ackno) && \
SEQ_LEQ(y->t_ackno, x->snd_hi))
/* ACK of local FIN */
#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_ucb->uc_rbuf == NULL && x->t_rcv_next == x->t_rcv_prev))
/* Enqueue/dequeue segment on tcp sequencing queue */
#ifdef vax
#define tcp_enq(x, y) insque(x, y)
#define tcp_deq(x) remque(x)
#else
#define tcp_enq(p, prev) \
{ register struct th *PREV = prev; \
\
p->t_prev = PREV; \
p->t_next = PREV->t_next; \
PREV->t_next->t_prev = p; \
PREV->t_next = p; \
}
#define tcp_deq(p) \
{ \
p->t_prev->t_next = p->t_next; \
p->t_next->t_prev = p->t_prev; \
}
#endif
sequence firstempty();