+#define TCP_PSH 0x08
+#define TCP_ACK 0x10
+#define TCP_URG 0x20
+
+
+extern void TCP_SendC(const tTCPConn *Conn, uint8_t flags, size_t data_len, const void *data);
+extern void TCP_Send(int IF, int AF, const void *IP, uint16_t sport, uint16_t dport, uint32_t seq, uint32_t ack, uint8_t flags, uint16_t window, size_t data_len, const void *data);
+
+// The following skip the next check of each field
+extern void TCP_SkipCheck_Seq(bool Skip);
+
+extern bool TCP_Pkt_CheckC(size_t len, const void *data, size_t *ofs, size_t *out_len, const tTCPConn *Conn, uint8_t flags);
+extern bool TCP_Pkt_Check(size_t len, const void *data, size_t *ofs, size_t *out_len, int AF, const void *IP, uint16_t sport, uint16_t dport, uint32_t seq, uint32_t ack, uint8_t flags);