1 /* tcp_var.h 4.13 81/12/12 */ 2 3 /* 4 * Kernel variables for tcp. 5 */ 6 7 /* 8 * Tcp control block, one per tcp; fields: 9 */ 10 struct tcpcb { 11 struct tcpiphdr *seg_next; /* sequencing queue */ 12 struct tcpiphdr *seg_prev; 13 short t_state; /* state of this connection */ 14 short t_timer[TCPT_NTIMERS]; /* tcp timers */ 15 short t_rxtshift; /* log(2) of rexmt exp. backoff */ 16 struct mbuf *t_tcpopt; /* tcp options */ 17 struct mbuf *t_ipopt; /* ip options */ 18 short t_maxseg; /* maximum segment size */ 19 char t_force; /* 1 if forcing out a byte */ 20 u_char t_flags; 21 #define TF_ACKNOW 0x01 /* ack peer immediately */ 22 #define TF_DELACK 0x02 /* ack, but try to delay it */ 23 #define TF_PUSH 0x04 /* push mode */ 24 #define TF_URG 0x08 /* urgent mode */ 25 #define TF_DONTKEEP 0x10 /* don't use keep-alives */ 26 struct tcpiphdr *t_template; /* skeletal packet for transmit */ 27 struct inpcb *t_inpcb; /* back pointer to internet pcb */ 28 /* 29 * The following fields are used as in the protocol specification. 30 * See RFC783, Dec. 1981, page 21. 31 */ 32 /* send sequence variables */ 33 tcp_seq snd_una; /* send unacknowledged */ 34 tcp_seq snd_nxt; /* send next */ 35 tcp_seq snd_up; /* send urgent pointer */ 36 tcp_seq snd_wl1; /* window update seg seq number */ 37 tcp_seq snd_wl2; /* window update seg ack number */ 38 tcp_seq iss; /* initial send sequence number */ 39 u_short snd_wnd; /* send window */ 40 /* receive sequence variables */ 41 short rcv_wnd; /* receive window */ 42 tcp_seq rcv_nxt; /* receive next */ 43 tcp_seq rcv_up; /* receive urgent pointer */ 44 tcp_seq irs; /* initial receive sequence number */ 45 /* 46 * Additional variables for this implementation. 47 */ 48 /* receive variables */ 49 tcp_seq rcv_adv; /* advertised window */ 50 /* retransmit variables */ 51 tcp_seq snd_max; /* highest sequence number sent 52 used to recognize retransmits */ 53 /* transmit timing stuff */ 54 short t_idle; /* inactivity time */ 55 short t_rtt; /* round trip time */ 56 tcp_seq t_rtseq; /* sequence number being timed */ 57 float t_srtt; /* smoothed round-trip time */ 58 }; 59 60 #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb) 61 #define sototcpcb(so) (intotcpcb(sotoinpcb(so))) 62 63 struct tcpstat { 64 int tcps_badsum; 65 int tcps_badoff; 66 int tcps_hdrops; 67 int tcps_badsegs; 68 int tcps_unack; 69 }; 70 71 #ifdef KERNEL 72 struct inpcb tcb; /* head of queue of active tcpcb's */ 73 struct tcpstat tcpstat; /* tcp statistics */ 74 struct tcpiphdr *tcp_template(); 75 #endif 76