1 /* tcp.h 1.9 81/10/29 */ 2 3 /* 4 * Tcp header. Fits over the ip header after option removed. 5 * 6 * SHOULD MAKE A CLEAN HEADER FOR USE BY USERS. 7 */ 8 struct th { 9 struct th *t_next; /* -> next tcp on rcv chain */ 10 struct th *t_prev; /* -> prev tcp on rcv chain */ 11 u_char t_x1; /* (unused) */ 12 u_char t_pr; /* protocol */ 13 /* by rights, t_len should be a u_short, but this makes operations */ 14 /* on it very dangerous as comparisons become unsigned and comparing */ 15 /* against negative numbers then fails... we don't expect any > 32767 */ 16 /* byte segments, so pragmatically delcare it to be a short */ 17 short t_len; /* seg length */ 18 struct socket t_s; /* source internet address */ 19 struct socket t_d; /* destination internet address */ 20 u_short t_src; /* source port */ 21 u_short t_dst; /* destination port */ 22 seq_t t_seq; /* sequence number */ 23 seq_t t_ackno; /* acknowledgement number */ 24 #define t_end(x) (x->t_seq + x->t_len - 1) 25 u_char 26 t_x2:4, /* (unused) */ 27 t_off:4; /* data offset */ 28 u_char th_flags; 29 #define TH_FIN 001 30 #define TH_SYN 002 31 #define TH_RST 004 32 #define TH_EOL 010 33 #define TH_ACK 020 34 #define TH_URG 040 35 u_short t_win; /* window */ 36 u_short t_sum; /* checksum */ 37 u_short t_urp; /* urgent pointer */ 38 }; 39 40 /* 41 * Tcp control block. 42 */ 43 struct tcb { 44 struct th *t_rcv_next; /* first el on rcv queue */ 45 struct th *t_rcv_prev; /* last el on rcv queue */ 46 struct tcb *t_tcb_next; /* next tcb */ 47 struct tcb *t_tcb_prev; /* next tcb */ 48 struct ucb *t_ucb; /* ucb */ 49 struct mbuf *t_rcv_unack; /* unacked message queue */ 50 short seqcnt; 51 short xxx; 52 seq_t iss; /* initial send seq # */ 53 seq_t irs; /* initial recv seq # */ 54 seq_t rcv_urp; /* rcv urgent pointer */ 55 seq_t rcv_nxt; /* next seq # to rcv */ 56 seq_t rcv_end; /* rcv eol pointer */ 57 seq_t snd_off; /* seq # of first datum in send buf */ 58 seq_t seq_fin; /* seq # of FIN sent */ 59 seq_t snd_end; /* send eol pointer */ 60 seq_t snd_urp; /* snd urgent pointer */ 61 seq_t snd_lst; /* seq # of last sent datum */ 62 seq_t snd_nxt; /* seq # of next datum to send */ 63 seq_t snd_una; /* seq # of first unacked datum */ 64 seq_t snd_wl; /* seq # of last sent window */ 65 seq_t snd_hi; /* highest seq # sent */ 66 seq_t snd_wnd; /* send window max */ 67 seq_t t_rexmt_val; /* val saved in rexmt timer */ 68 seq_t t_rtl_val; /* val saved in rexmt too long timer */ 69 seq_t t_xmt_val; /* seq # sent when xmt timer started */ 70 71 /* various flags and state variables */ 72 73 u_short tc_flags; 74 #define TC_ACK_DUE 0x0001 /* must we send ACK */ 75 #define TC_CANCELLED 0x0002 /* retransmit timer cancelled */ 76 #define TC_DROPPED_TXT 0x0004 /* dropped incoming data */ 77 #define TC_FIN_RCVD 0x0008 /* FIN received */ 78 #define TC_FORCE_ONE 0x0010 /* force sending of one byte */ 79 #define TC_NEW_WINDOW 0x0020 /* received new window size */ 80 #define TC_REXMT 0x0040 /* this msg is a retransmission */ 81 #define TC_SND_FIN 0x0080 /* FIN should be sent */ 82 #define TC_SND_RST 0x0100 /* RST should be sent */ 83 #define TC_SND_URG 0x0200 /* urgent data to send */ 84 #define TC_SYN_ACKED 0x0400 /* SYN has been ACKed */ 85 #define TC_SYN_RCVD 0x0800 /* SYN has been received */ 86 #define TC_USR_CLOSED 0x1000 /* user has closed connection */ 87 #define TC_WAITED_2_ML 0x2000 /* wait time for FIN ACK is up */ 88 #define TC_NET_KEEP 0x4000 /* don't free this net input */ 89 #define TC_USR_ABORT 0x8000 /* user has closed and does not expect 90 to receive any more data */ 91 92 u_short t_lport; /* local port */ 93 u_short t_fport; /* foreign port */ 94 u_char t_state; /* state of this connection */ 95 u_char t_xmtime; /* current rexmt time */ 96 97 /* timers */ 98 99 u_char t_init; /* initialization too long */ 100 u_char t_rexmt; /* retransmission */ 101 u_char t_rexmttl; /* retransmit too long */ 102 u_char t_persist; /* retransmit persistance */ 103 u_char t_finack; /* fin acknowledged */ 104 u_char t_xmt; /* round trip transmission time */ 105 }; 106 107 /* 108 * TCP timers. 109 */ 110 #define TINIT 1 111 #define TREXMT 2 112 #define TREXMTTL 3 113 #define TPERSIST 4 114 #define TFINACK 5 115 116 /* 117 * Tcp machine predicates 118 */ 119 #define ack_ok(x, y) \ 120 (((y)->th_flags&TH_ACK)==0 || \ 121 ((x)->iss < (y)->t_ackno && (y)->t_ackno <= (x)->snd_hi)) 122 123 #define syn_ok(x, y) \ 124 ((y)->th_flags&TH_SYN) 125 126 #define ack_fin(x, y) \ 127 ((x)->seq_fin > (x)->iss && (y)->t_ackno > (x)->seq_fin) 128 129 #define rcv_empty(x) \ 130 (((x)->tc_flags&TC_USR_ABORT) || \ 131 ((x)->t_ucb->uc_rbuf == NULL && (x)->t_rcv_next == (x)->t_rcv_prev)) 132 133 /* 134 * THESE NEED TO BE JUSTIFIED! 135 */ 136 #define ISSINCR 128 /* increment for iss each second */ 137 #define TCPROTO 6 /* TCP-4 protocol number */ 138 #define TCPSIZE 20 /* size of TCP leader (bytes) */ 139 #define T_2ML 10 /* 2*maximum packet lifetime */ 140 #define T_PERS 5 /* persist time */ 141 #define T_INIT 30 /* init too long timeout */ 142 #define T_REXMT 1 /* base for retransmission time */ 143 #define T_REXMTTL 30 /* retransmit too long timeout */ 144 #define T_REMAX 30 /* maximum retransmission time */ 145 #define ACTIVE 1 /* active open */ 146 #define PASSIVE 0 /* passive open */ 147 148 #ifdef TCPDEBUG 149 #define TDBSIZE 50 150 /* 151 * Tcp debugging record. 152 */ 153 struct tcp_debug { 154 long td_tod; /* time of day */ 155 struct tcb *td_tcb; /* -> tcb */ 156 char td_old; /* old state */ 157 char td_inp; /* input */ 158 char td_tim; /* timer id */ 159 char td_new; /* new state */ 160 seq_t td_sno; /* seq_t number */ 161 seq_t td_ano; /* acknowledgement */ 162 u_short td_wno; /* window */ 163 u_short td_lno; /* length */ 164 u_char td_flg; /* message flags */ 165 }; 166 #endif 167 168 #ifdef KERNEL 169 struct tcb *tcb_head, *tcb_tail; /* tcp tcb list */ 170 seq_t tcp_iss; /* tcp initial send seq # */ 171 int tcpconsdebug; /* set to 1 traces on console */ 172 #ifdef TCPDEBUG 173 struct tcp_debug tcp_debug[TDBSIZE]; 174 #endif 175 int tdbx; /* rotating index into tcp_debug */ 176 struct th *tcp_template(); 177 #endif 178 179 #define SEQ_LT(a,b) ((int)((a)-(b)) < 0) 180 #define SEQ_LEQ(a,b) ((int)((a)-(b)) <= 0) 181 #define SEQ_GT(a,b) ((int)((a)-(b)) > 0) 182 #define SEQ_GEQ(a,b) ((int)((a)-(b)) >= 0) 183