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TCP Sockets
[Socket API]

TCP sockets. More...

Data Structures
struct	tcp_socket
	TCP socket information structure. More...
struct	tcp_socket
	TCP socket information structure. More...
Defines
#define	SO_FIN
	Send FIN after all data has been transmitted.
#define	SO_SYN
	Send SYN first.
#define	SO_FORCE
	Force sending ACK.
#define	SO_ACK
	Send ACK.
Typedefs
typedef tcp_socket	TCPSOCKET
	TCP socket type.
Functions
void	NutTcpDestroySocket (TCPSOCKET *sock)
	Destroy a previously allocated socket.
TCPSOCKET *	NutTcpFindSocket (u_short lport, u_short rport, u_long raddr)
	Find a matching socket.
TCPSOCKET *	NutTcpCreateSocket (void)
	Create a TCP socket.
int	NutTcpSetSockOpt (TCPSOCKET *sock, int optname, CONST void *optval, int optlen)
	Set value of a TCP socket option.
int	NutTcpGetSockOpt (TCPSOCKET *sock, int optname, void *optval, int optlen)
	Get a TCP socket option value.
int	NutTcpConnect (TCPSOCKET *sock, u_long addr, u_short port)
	Connect to a remote socket.
int	NutTcpAccept (TCPSOCKET *sock, u_short port)
	Wait for incoming connect from a remote socket.
int	NutTcpSend (TCPSOCKET *sock, CONST void *data, u_short len)
	Send data on a connected TCP socket.
int	NutTcpReceive (TCPSOCKET *sock, void *data, u_short size)
	Receive data on a connected TCP socket.
int	NutTcpCloseSocket (TCPSOCKET *sock)
	Close TCP socket.
int	NutTcpError (TCPSOCKET *sock)
	Return specific code of the last error.
int	NutTcpDeviceRead (TCPSOCKET *sock, void *buffer, int size)
	Read from device.
int	NutTcpDeviceWrite (TCPSOCKET *sock, CONST void *buffer, int size)
	Write to a socket.
int	NutTcpDeviceWrite_P (TCPSOCKET *sock, PGM_P buffer, int size)
	Write to device.
int	NutTcpDeviceIOCtl (TCPSOCKET *sock, int cmd, void *param)
	Driver control function.
Variables
TCPSOCKET *	tcpSocketList

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Detailed Description

TCP sockets.

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Typedef Documentation

typedef struct tcp_socket TCPSOCKET

TCP socket type.

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Function Documentation

int NutTcpAccept (  TCPSOCKET *    sock, u_short    port )

Wait for incoming connect from a remote socket. The calling thread will be suspended until until an incoming connection request is received. This function is typically used by TCP server applications. Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket(). port  Port number to listen to (host byte order). Returns: 0 on success, -1 otherwise. The specific error code can be retrieved by calling NutTcpError(). Examples: httpd/httpserv.c, portdio/portdio.c, and tcps/tcps.c.

int NutTcpCloseSocket (  TCPSOCKET *    sock )

Close TCP socket. Note, that the socket may not be immediately destroyed after calling this function. However, the application must not use the socket after this call. Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket(). Returns: 0 on success, -1 otherwise. Examples: httpd/httpserv.c, inetq/inetq.c, portdio/portdio.c, rs232d/rs232d.c, and tcps/tcps.c.

int NutTcpConnect (  TCPSOCKET *    sock, u_long    addr, u_short    port )

Connect to a remote socket. This function tries to establish a connection to the specified remote port of the specified remote server. The calling thread will be suspended until a connection is successfully established or an error occurs. This function is typically used by TCP client applications. Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket(). addr  IP address of the host to connect (network byte order). port  Port number to connect (host byte order). Returns: 0 on success, -1 otherwise. The specific error code can be retrieved by calling NutTcpError(). Examples: inetq/inetq.c.

TCPSOCKET* NutTcpCreateSocket (  void    )

Create a TCP socket. Allocates a TCPSOCKET structure from heap memory, initializes it and returns a pointer to that structure. The first call will also start the TCP timer, which is required by various timeout checks. Returns: Socket descriptor of the newly created TCP socket or 0 if there is not enough memory left. Todo: Avoid fixed initial sequence number. Configurable buffer size. Allow larger maximum segment size. Examples: httpd/httpserv.c, inetq/inetq.c, portdio/portdio.c, rs232d/rs232d.c, and tcps/tcps.c.

void NutTcpDestroySocket (  TCPSOCKET *    sock )

Destroy a previously allocated socket. Remove socket from the socket list and release occupied memory. Applications typically do not need to call this function. It is automatically called by a timer after the socket has been closed by NutTcpCloseSocket(). Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket().

int NutTcpDeviceIOCtl (  TCPSOCKET *    sock, int    cmd, void *    param )

Driver control function. Used to modify or query device specific settings. Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket().

int NutTcpDeviceRead (  TCPSOCKET *    sock, void *    buffer, int    size )

Read from device. Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket().

int NutTcpDeviceWrite (  TCPSOCKET *    sock, CONST void *    buffer, int    size )

Write to a socket. In contrast to NutTcpSend() this routine provides some buffering. Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket().

int NutTcpDeviceWrite_P (  TCPSOCKET *    sock, PGM_P    buffer, int    size )

Write to device. Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket(). Warning: Inefficient implementation.

int NutTcpError (  TCPSOCKET *    sock )

Return specific code of the last error. Possible error codes (net/errno.h) are: EWOULDBLOCK: Operation would block EINPROGRESS: Operation now in progress EALREADY: Operation already in progress ENOTSOCK: Socket operation on non-socket EDESTADDRREQ: Destination address required EMSGSIZE: Message too long EPROTOTYPE: Protocol wrong type for socket ENOPROTOOPT: Protocol not available EPROTONOSUPPORT: Protocol not supported ESOCKTNOSUPPORT: Socket type not supported EOPNOTSUPP: Operation not supported on socket EPFNOSUPPORT: Protocol family not supported EAFNOSUPPORT: Address family not supported by protocol family EADDRINUSE: Address already in use EADDRNOTAVAIL: Can't assign requested address ENETDOWN: Network is down ENETUNREACH: Network is unreachable ENETRESET: Network dropped connection on reset ECONNABORTED: Software caused connection abort ECONNRESET: Connection reset by peer ENOBUFS: No buffer space available EISCONN: Socket is already connected ENOTCONN: Socket is not connected ESHUTDOWN: Can't send after socket shutdown ETOOMANYREFS: Too many references: can't splice ETIMEDOUT: Connection timed out ECONNREFUSED: Connection refused ELOOP: Too many levels of symbolic links ENAMETOOLONG: File name too long EHOSTDOWN: Host is down EHOSTUNREACH: No route to host ENOTEMPTY: Directory not empty Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket(). Note: Applications must not call this function to retrieve the error code if NutTcpCloseSocket() or NutTcpDestroySocket() failed. Bug: Not all error codes are properly set right now. Some socket functions return an error without setting an error code.

TCPSOCKET* NutTcpFindSocket (  u_short    lport, u_short    rport, u_long    raddr )

Find a matching socket. Loop through all sockets and find a matching connection (prefered) or a listening socket. Applications typically do not need to call this function. Parameters: lport  Local port number. rport  Remote port number. raddr  Remote IP address in network byte order. Returns: Socket descriptor.

int NutTcpGetSockOpt (  TCPSOCKET *    sock, int    optname, void *    optval, int    optlen )

Get a TCP socket option value. The following values can be set: TCP_MAXSEG Maximum segment size (u_short). SO_SNDTIMEO Socket send timeout (u_long). SO_RCVTIMEO Socket receive timeout (u_long). Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket(). optname  Option to get. optval  Points to a buffer receiving the value. optlen  Length of the value buffer. Returns: 0 on success, -1 otherwise. The specific error code can be retrieved by calling NutTcpError().

int NutTcpReceive (  TCPSOCKET *    sock, void *    data, u_short    size )

Receive data on a connected TCP socket. Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket(). In addition a connection must have been established by calling NutTcpConnect or NutTcpAccept. data  Pointer to the buffer that receives the data. size  Size of the buffer. Returns: If successful, the number of received data bytes is returned. This may be less than the specified size of the buffer. The return value 0 indicates a timeout, while -1 is returned in case of an error or broken connection. Call NutTcpError() to determine the specific error code. Examples: inetq/inetq.c, and rs232d/rs232d.c.

int NutTcpSend (  TCPSOCKET *    sock, CONST void *    data, u_short    len )

Send data on a connected TCP socket. Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket(). In addition a connection must have been established by calling NutTcpConnect or NutTcpAccept. data  Pointer to a buffer containing the data to send. len  Number of bytes to be sent. Returns: If successful, the number of bytes added to the socket transmit buffer. This may be less than the specified number of bytes to send. The return value -1 indicates a fatal error. Examples: inetq/inetq.c, and rs232d/rs232d.c.

int NutTcpSetSockOpt (  TCPSOCKET *    sock, int    optname, CONST void *    optval, int    optlen )

Set value of a TCP socket option. The following values can be set: TCP_MAXSEG Maximum segment size (u_short). SO_SNDTIMEO Socket send timeout (u_long). SO_RCVTIMEO Socket receive timeout (u_long). Parameters: sock  Socket descriptor. This pointer must have been retrieved by calling NutTcpCreateSocket(). optname  Option to set. optval  Pointer to the value. optlen  Length of the value. Returns: 0 on success, -1 otherwise. The specific error code can be retrieved by calling NutTcpError().

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Variable Documentation

TCPSOCKET* tcpSocketList

Linked list of all TCP sockets.

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