1*5065Swnj /* tcp.h 1.18 81/11/24 */ 24573Swnj 34573Swnj /* 44899Swnj * TCP header. 54924Swnj * Per RFC 793, September, 1981. 64573Swnj */ 74899Swnj struct tcphdr { 84899Swnj u_short th_sport; /* source port */ 94899Swnj u_short th_dport; /* destination port */ 104899Swnj seq_t th_seq; /* sequence number */ 114899Swnj seq_t th_ackno; /* acknowledgement number */ 124573Swnj u_char 134899Swnj th_x2:4, /* (unused) */ 144899Swnj th_off:4; /* data offset */ 154575Swnj u_char th_flags; 16*5065Swnj #define TH_FIN 0x01 17*5065Swnj #define TH_SYN 0x02 18*5065Swnj #define TH_RST 0x04 19*5065Swnj #define TH_PUSH 0x08 20*5065Swnj #define TH_ACK 0x10 21*5065Swnj #define TH_URG 0x20 224899Swnj u_short th_win; /* window */ 234899Swnj u_short th_sum; /* checksum */ 244899Swnj u_short th_urp; /* urgent pointer */ 254499Swnj }; 26