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tcp.h

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/*!     \file include/net/tcp.h
 *      \brief Header for the TCP (Transmition Control Protocol).
 *      \author Andrea Righi <drizzt@inwind.it>
 *      \date 2003-10-27
 *      \note Copyright (C) 2003 Andrea Righi
 */

#ifndef TCP_H
#define TCP_H

/** \ingroup Network
 *  \defgroup NetTCP TCP (Transmition Control Protocol) layer
 *  The TCP (Transmition Control Protocol) layer.
 *  @{
 */

//! TCP connection closed state.
#define TCP_CLOSED      0
//! TCP SYN received state.
#define TCP_SYN_RCVD    1
//! TCP SYN sent state.
#define TCP_SYN_SENT    2
//! TCP connection established state.
#define TCP_ESTABLISHED 3
//! TCP closing state.
#define TCP_CLOSING     4

//! A socket structure.
typedef struct
{
        //! IP source address (in network format).
        in_addr_t ip_src;
        //! Source port.
        uint16_t port_src;
        //! IP destination address (in network format).
        in_addr_t ip_dst;
        //! Destination port.
        uint16_t port_dst;
} socket_t;

//! A TCP connection states machine structure.
typedef struct
{
        // The state of the connection.
        int state;
        //! The socket used in the connection.
        socket_t socket;
        //! The current sequence number.
        int seq_num;
} tcp_state_t;

//! TCP packet structure.
typedef struct tcp
{
        //! Source port.
        uint16_t tcp_src;
        //! Destination port.
        uint16_t tcp_dst;

        //! Sequence number.
        uint32_t tcp_seq_num;
        //! ACK number.
        uint32_t tcp_ack_num;

#if __BYTE_ORDER__ == __LITTLE_ENDIAN__
        //! Reserved (bit 0..3).
        uint8_t tcp_res1:4;
        //! Header length.
        uint8_t tcp_hdr_len:4;
        //! FIN flag.
        uint8_t tcp_fin:1;
        //! SYN flag.
        uint8_t tcp_syn:1;
        //! RST flag.
        uint8_t tcp_rst:1;
        //! PSH flag.
        uint8_t tcp_psh:1;
        //! ACK flag.
        uint8_t tcp_ack:1;
        //! URG flag.
        uint8_t tcp_urg:1;
        //! Reserved (bit 4..6).
        uint8_t tcp_res2:2;
#else
        //! Header length.
        uint8_t tcp_hdr_len:4;
        //! Reserved.
        uint8_t tcp_res:6;
        //! URG flag.
        uint8_t tcp_urg:1;
        //! ACK flag.
        uint8_t tcp_ack:1;
        //! PSH flag.
        uint8_t tcp_psh:1;
        //! RST flag.
        uint8_t tcp_rst:1;
        //! SYN flag.
        uint8_t tcp_syn:1;
        //! FIN flag.
        uint8_t tcp_fin:1;
#endif
        //! Window size.
        uint16_t tcp_win_size;
        //! TCP checksum.
        uint16_t tcp_chk;
        //! Urgent pointer.
        uint16_t tcp_urg_ptr;
        
} __attribute__ ((packed)) tcp_t;

// --- Prototypes ----------------------------------------------------- //

void to_tcp_layer(tcp_t *packet, size_t len, in_addr_t ip_src, in_addr_t ip_dst);
int tcp_module_init();
int tcp_module_close();

/** @} */ // end of NetTCP

#endif

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