1 /* tcp.h 1.23 82/12/28 */ 2 3 typedef u_long tcp_seq; 4 /* 5 * TCP header. 6 * Per RFC 793, September, 1981. 7 */ 8 struct tcphdr { 9 u_short th_sport; /* source port */ 10 u_short th_dport; /* destination port */ 11 tcp_seq th_seq; /* sequence number */ 12 tcp_seq th_ack; /* acknowledgement number */ 13 #ifdef vax 14 u_char th_x2:4, /* (unused) */ 15 th_off:4; /* data offset */ 16 #endif 17 #ifdef sun 18 u_char th_off:4, /* data offset */ 19 th_x2:4; /* (unused) */ 20 #endif 21 u_char th_flags; 22 #define TH_FIN 0x01 23 #define TH_SYN 0x02 24 #define TH_RST 0x04 25 #define TH_PUSH 0x08 26 #define TH_ACK 0x10 27 #define TH_URG 0x20 28 u_short th_win; /* window */ 29 u_short th_sum; /* checksum */ 30 u_short th_urp; /* urgent pointer */ 31 }; 32 33 #define TCPOPT_EOL 0 34 #define TCPOPT_NOP 1 35 #define TCPOPT_MAXSEG 2 36