#ifndef TCP_H
#define TCP_H

typedef unsigned short int WORD;
typedef unsigned long int DWORD;
typedef int BOOL;
#define TRUE 1
#define FALSE 0

// TCP Header stuff

#define TCPIP_HEADER_SIZE 40  // size in bytes
// Header for a TCP/IP packet
typedef struct TCPIP_Packet {
    // IP fields
    WORD ver_len_qos; // check against common value
    WORD length;      // data len = length - 20, if ver_len_qos check passes
	WORD ident;       // sequence number, should ignore
	WORD flags_offset;// check against common value
	WORD ttl_proto;   // check against common value
	WORD header_checksum; // have to calc and verify this
	DWORD source_IP;  // should ignore, will need for ACK
	DWORD dest_IP;    // should ignore
	// TCP fields
	DWORD ports;  // Put two ports together for one comparison
//	WORD source_port; // handled by NI, will need for ACK
//	WORD dest_port;   // handled by NI
	DWORD seq_number; // check that this is next expected sequence number
	DWORD ack_number; // use to update non-stable packet list
	WORD off_flags;   // check against common value
	WORD window;      // use to update window value
	short checksum;    // have to check this, should be done by NI
	WORD urgent_ptr;  // should ignore
	WORD data;
	} TCPIP_Packet;

// Current maximum queue size
#define MAX_Q_SIZE 64

// What a queue entry holds
typedef struct Q {
    DWORD head, tail; // tail points to first free buffer 
    DWORD number[MAX_Q_SIZE]; // sequence number last byte in packet...not always used
    void *header[MAX_Q_SIZE]; // pointer to header...not always used
    void *data[MAX_Q_SIZE];   // pointer to data or packet
	} Q;

// Wrap-around int operations
#define LESS_THAN(A, B) ((A)-(B)<0)
#define EQUAL(A,B) (A==B)
#define GREATER_THAN(A,B) ((A)-(B)>0)

typedef struct SocketInfo { // This holds info about a socket
	DWORD next_seq_number; // next expected seq number
	DWORD highest_ack;	   // highest ack we have received
	int bytes_unacked;	   // number of bytes we have received without 
  					   //    sending an ACK
	WORD window;           // how much can we send? (receiver's window)
	WORD congestionWindow; // window limit for congestion
	WORD maxSegmentSize;   //
	DWORD highest_seq_number;  // The highest sequence number we have received
					   // This may be different than next_seq_num
	WORD receiveWindow; // max value we can receive at present moment              
	WORD maxReceiveWindow;  // max value we can receive period
	DWORD senderSeqNumber; // Sender's sequence number
	WORD slowStartThreshold; // Threshold where slow start ends
	TCPIP_Packet sendHeader; // cached values for packet to be sent
	} SocketInfo;

#define MAX_OUTSTANDING 64 // Maximum # of packets we can have outstanding at a time
#define MAX_OUT_Q // Maximum # of packets we can have in our outgoing Q

#define TCP_PROTO_NUMBER 4  // This isn't right...fix

#endif //TCP.H