1 /* tcp.h 1.8 81/10/29 */ 2 3 /* 4 * Tcp header (fits over ip header). 5 */ 6 struct th { 7 struct th *t_next; /* -> next tcp on rcv chain */ 8 struct th *t_prev; /* -> prev tcp on rcv chain */ 9 u_char t_x1; /* (unused) */ 10 u_char t_pr; /* protocol */ 11 /* by rights, t_len should be a u_short, but this makes operations */ 12 /* on it very dangerous as comparisons become unsigned and comparing */ 13 /* against negative numbers then fails... we don't expect any > 32767 */ 14 /* byte segments, so pragmatically delcare it to be a short */ 15 short t_len; /* seg length */ 16 struct socket t_s; /* source internet address */ 17 struct socket t_d; /* destination internet address */ 18 u_short t_src; /* source port */ 19 u_short t_dst; /* destination port */ 20 seq_t t_seq; /* sequence number */ 21 seq_t t_ackno; /* acknowledgement number */ 22 #define t_end(x) (x->t_seq + x->t_len - 1) 23 u_char 24 t_x2:4, /* (unused) */ 25 t_off:4; /* data offset */ 26 u_char th_flags; 27 #define TH_FIN 001 28 #define TH_SYN 002 29 #define TH_RST 004 30 #define TH_EOL 010 31 #define TH_ACK 020 32 #define TH_URG 040 33 u_short t_win; /* window */ 34 u_short t_sum; /* checksum */ 35 u_short t_urp; /* urgent pointer */ 36 }; 37 38 /* 39 * Tcp control block. 40 */ 41 struct tcb { 42 struct th *t_rcv_next; /* first el on rcv queue */ 43 struct th *t_rcv_prev; /* last el on rcv queue */ 44 struct tcb *t_tcb_next; /* next tcb */ 45 struct tcb *t_tcb_prev; /* next tcb */ 46 struct ucb *t_ucb; /* ucb */ 47 struct mbuf *t_rcv_unack; /* unacked message queue */ 48 short seqcnt; 49 short xxx; 50 seq_t iss; /* initial send seq # */ 51 seq_t irs; /* initial recv seq # */ 52 seq_t rcv_urp; /* rcv urgent pointer */ 53 seq_t rcv_nxt; /* next seq # to rcv */ 54 seq_t rcv_end; /* rcv eol pointer */ 55 seq_t snd_off; /* seq # of first datum in send buf */ 56 seq_t seq_fin; /* seq # of FIN sent */ 57 seq_t snd_end; /* send eol pointer */ 58 seq_t snd_urp; /* snd urgent pointer */ 59 seq_t snd_lst; /* seq # of last sent datum */ 60 seq_t snd_nxt; /* seq # of next datum to send */ 61 seq_t snd_una; /* seq # of first unacked datum */ 62 seq_t snd_wl; /* seq # of last sent window */ 63 seq_t snd_hi; /* highest seq # sent */ 64 seq_t snd_wnd; /* send window max */ 65 seq_t t_rexmt_val; /* val saved in rexmt timer */ 66 seq_t t_rtl_val; /* val saved in rexmt too long timer */ 67 seq_t t_xmt_val; /* seq # sent when xmt timer started */ 68 69 /* various flags and state variables */ 70 71 u_short tc_flags; 72 #define TC_ACK_DUE 0x0001 /* must we send ACK */ 73 #define TC_CANCELLED 0x0002 /* retransmit timer cancelled */ 74 #define TC_DROPPED_TXT 0x0004 /* dropped incoming data */ 75 #define TC_FIN_RCVD 0x0008 /* FIN received */ 76 #define TC_FORCE_ONE 0x0010 /* force sending of one byte */ 77 #define TC_NEW_WINDOW 0x0020 /* received new window size */ 78 #define TC_REXMT 0x0040 /* this msg is a retransmission */ 79 #define TC_SND_FIN 0x0080 /* FIN should be sent */ 80 #define TC_SND_RST 0x0100 /* RST should be sent */ 81 #define TC_SND_URG 0x0200 /* urgent data to send */ 82 #define TC_SYN_ACKED 0x0400 /* SYN has been ACKed */ 83 #define TC_SYN_RCVD 0x0800 /* SYN has been received */ 84 #define TC_USR_CLOSED 0x1000 /* user has closed connection */ 85 #define TC_WAITED_2_ML 0x2000 /* wait time for FIN ACK is up */ 86 #define TC_NET_KEEP 0x4000 /* don't free this net input */ 87 #define TC_USR_ABORT 0x8000 /* user has closed and does not expect 88 to receive any more data */ 89 90 u_short t_lport; /* local port */ 91 u_short t_fport; /* foreign port */ 92 u_char t_state; /* state of this connection */ 93 u_char t_xmtime; /* current rexmt time */ 94 95 /* timers */ 96 97 u_char t_init; /* initialization too long */ 98 u_char t_rexmt; /* retransmission */ 99 u_char t_rexmttl; /* retransmit too long */ 100 u_char t_persist; /* retransmit persistance */ 101 u_char t_finack; /* fin acknowledged */ 102 u_char t_xmt; /* round trip transmission time */ 103 }; 104 105 /* 106 * Tcp machine predicates 107 */ 108 #define ack_ok(x, y) \ 109 (((y)->th_flags&TH_ACK)==0 || \ 110 ((x)->iss < (y)->t_ackno && (y)->t_ackno <= (x)->snd_hi)) 111 112 #define syn_ok(x, y) \ 113 ((y)->th_flags&TH_SYN) 114 115 #define ack_fin(x, y) \ 116 ((x)->seq_fin > (x)->iss && (y)->t_ackno > (x)->seq_fin) 117 118 #define rcv_empty(x) \ 119 (((x)->tc_flags&TC_USR_ABORT) || \ 120 ((x)->t_ucb->uc_rbuf == NULL && (x)->t_rcv_next == (x)->t_rcv_prev)) 121 122 #define ISSINCR 128 /* increment for iss each second */ 123 #define TCPROTO 6 /* TCP-4 protocol number */ 124 #define TCPSIZE 20 /* size of TCP leader (bytes) */ 125 #define T_2ML 10 /* 2*maximum packet lifetime */ 126 #define T_PERS 5 /* persist time */ 127 #define T_INIT 30 /* init too long timeout */ 128 #define T_REXMT 1 /* base for retransmission time */ 129 #define T_REXMTTL 30 /* retransmit too long timeout */ 130 #define T_REMAX 30 /* maximum retransmission time */ 131 #define ACTIVE 1 /* active open */ 132 #define PASSIVE 0 /* passive open */ 133 134 #ifdef TCPDEBUG 135 #define TDBSIZE 50 136 /* 137 * Tcp debugging record. 138 */ 139 struct tcp_debug { 140 long td_tod; /* time of day */ 141 struct tcb *td_tcb; /* -> tcb */ 142 char td_old; /* old state */ 143 char td_inp; /* input */ 144 char td_tim; /* timer id */ 145 char td_new; /* new state */ 146 seq_t td_sno; /* seq_t number */ 147 seq_t td_ano; /* acknowledgement */ 148 u_short td_wno; /* window */ 149 u_short td_lno; /* length */ 150 u_char td_flg; /* message flags */ 151 }; 152 #ifdef KERNEL 153 int tcpconsdebug; /* set to 1 traces on console */ 154 struct tcp_debug tcp_debug[TDBSIZE]; 155 int tdbx; /* rotating index into tcp_debug */ 156 #endif 157 #endif 158 159 #define SEQ_LT(a,b) ((int)((a)-(b)) < 0) 160 #define SEQ_LEQ(a,b) ((int)((a)-(b)) <= 0) 161 #define SEQ_GT(a,b) ((int)((a)-(b)) > 0) 162 #define SEQ_GEQ(a,b) ((int)((a)-(b)) >= 0) 163