nmsgLib.c File Reference

Routines for handling formatted network messages. More...

#include <NMSG/nmsgLib.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <pthread.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>

Functions
int	nmsgCheck (void *hndl)
	Check a network connection handle.
int	nmsgClose (void *hndl, int force)
	Terminate a message client or server.
int	nmsgConnect (void **hndl, const char *node, int port)
	Connect to a message server.
int	nmsgConnectAsy (void **hndl, const char *node, int port, int prio, nmsgConnCB_t connRtn, nmsgDiscCB_t discRtn, void *uParm)
	Connect asynchronously (robustly) to a message server.
const char *	nmsgErrorMsg (int status)
	Obtain the text of an error message.
void	nmsgErrorReport (int status, const char *func)
	Display an error message.
int	nmsgListen (void **hndl, int port, int maxConn, int maxData, int prio, nmsgConnCB_t connRtn, nmsgDiscCB_t discRtn, nmsgRcveCB_t rcveRtn, void *uParm)
	Establish a message server.
int	nmsgRemoteIP (void *hndl, int *ip)
	Get the IP address of the remote end.
int	nmsgSend (void *hndl, nmsgBuff_t *msg)
	Send a message and return immediately.
int	nmsgSendW (void *hndl, nmsgBuff_t *msg, nmsgBuff_t **replyP, nmsgBuff_t *reply, int maxData)
	Send a message and receive reply.
int	nmsgStats (void *hndl, nmsgStats_t *stats)
	Get connection statistics.
int	nmsgWait (void *hndl, nmsgBuff_t **replyP, nmsgBuff_t *reply, int maxData)
	Wait for a reply to a sent message.

---

Detailed Description

Routines for handling formatted network messages.

Author:

Owen H Saxton

Id

nmsgLib.c,v 1.14 2011/03/28 18:39:49 saxton Exp

---

Function Documentation

int nmsgCheck

(

void *

hndl

)

Check a network connection handle.

This routine checks whether a network handle is valid or not.

Parameters:

hndl

The handle for the connection.

Return values:

	1	The handle is valid.
	0	The handle is invalid.

References NMSG_MAGIC.

int nmsgClose	(	void *	hndl,
		int	force
	)

Terminate a message client or server.

This routine closes a network connection or stops a network server.

Parameters:

	hndl	The handle of the connection or server.
	force	For a client connection, if TRUE, the connection is closed even if another task is in the process of sending a message. If FALSE, the closing waits until any activity has ceased. Not used for a server.

Return values:

	NMSG_SUCCESS	Success.
	NMSG_INVHNDL	Invalid network handle.

References NMSG_INVHNDL, NMSG_MAGIC, and NMSG_SUCCESS.

int nmsgConnect	(	void **	hndl,
		const char *	node,
		int	port
	)

Connect to a message server.

This routine establishes a network connection to a message server.

Parameters:

	hndl	The address of a pointer to receive the identifying handle for the network connection.
	node	The address of the name of the node containing the message server.
	port	The port number on which to establish the connection.

Return values:

	NMSG_SUCCESS	The connection was established successfully.
	NMSG_NOMEMORY	Insuffucuent memory available.
	NMSG_UNKNHOST	Host is unknown.
	NMSG_NOSEMCRE	Unable to create sync. semaphore (VxWorks)
	NMSG_xxx	Various connection errors.

References NMSG_MAGIC, NMSG_NOMEMORY, NMSG_NOSEMCRE, NMSG_SUCCESS, and NMSG_UNKNHOST.

int nmsgConnectAsy	(	void **	hndl,
		const char *	node,
		int	port,
		int	prio,
		nmsgConnCB_t	connRtn,
		nmsgDiscCB_t	discRtn,
		void *	uParm
	)

Connect asynchronously (robustly) to a message server.

This routine establishes a robust network connection to a message server. The connection is done asynchronously, and the attempt is retried periodically if the initial attempt fails, or if the connection is broken.

Parameters:

	hndl	The address of a pointer to receive the identifying handle for the network connection.
	node	The address of the name of the node containing the message server.
	port	The port number on which to establish the connection.
	prio	The priority of the connection task, where applicable. If 0, the default value (100) is used.
	connRtn	The address of a routine to be called when the connection has been made.
	discRtn	The address of a routine to be called when the connection is broken.
	uParm	A parameter to be passed to the connect and disconnect callback routines.

Return values:

	NMSG_SUCCESS	The connection was established successfully.
	NMSG_NOMEMORY	Insuffucuent memory available.
	NMSG_UNKNHOST	Host is unknown.
	NMSG_NOSEMCRE	Unable to create sync. semaphore (VxWorks)
	NMSG_NOTASKCR	Unable to spawn connection task.

References NMSG_MAGIC, NMSG_NOMEMORY, NMSG_NOSEMCRE, NMSG_SUCCESS, and NMSG_UNKNHOST.

const char* nmsgErrorMsg

(

int

status

)

Obtain the text of an error message.

This routine returns a pointer to the message corresponding to a given NMSG status code.

Parameters:

status

The NMSG status code.

Returns:

The address of the corresponding message text.

References NMSG_ADDRUNAV, NMSG_ADDRUSED, NMSG_ALREADY, NMSG_BADADDRS, NMSG_BADFNMBR, NMSG_BRKNPIPE, NMSG_CONNABRT, NMSG_CONNREF, NMSG_CONNRSET, NMSG_CONNTMO, NMSG_DISCONN, NMSG_FILENFND, NMSG_HOSTDOWN, NMSG_HSTUNRCH, NMSG_INPROGRS, NMSG_INVDARG, NMSG_INVHNDL, NMSG_INVSEMA, NMSG_IOERROR, NMSG_MSGLONG, NMSG_NAMELONG, NMSG_NETDOWN, NMSG_NETRESET, NMSG_NETUNRCH, NMSG_NOACCESS, NMSG_NOBUFSPC, NMSG_NOMEMORY, NMSG_NOSCHDEV, NMSG_NOSEMCRE, NMSG_NOSTREAM, NMSG_NOTADIR, NMSG_NOTAFILE, NMSG_NOTASKCR, NMSG_NOTASOCK, NMSG_NOTCONN, NMSG_OPNTPERM, NMSG_OPNTSUPP, NMSG_OPRNINTR, NMSG_PROTOERR, NMSG_PROTOTYP, NMSG_RDONLYFS, NMSG_SHUTDOWN, NMSG_SNOTCONN, NMSG_SOCKCONN, NMSG_SUCCESS, NMSG_TIMEDOUT, NMSG_TOODEEP, NMSG_TRYAGAIN, NMSG_UNKNERR, NMSG_UNKNHOST, NMSG_UNSUPADF, NMSG_UNSUPPRF, NMSG_UNSUPPRO, NMSG_XSFILDVC, and NMSG_XSFILOPN.

Referenced by nmsgErrorReport().

void nmsgErrorReport	(	int	status,
		const char *	func
	)

Display an error message.

This routine outputs to stderr the message corresponding to a given NMSG status code.

Parameters:

	status	The NMSG status code.
	func	The function name to be displayed at the start of the message.

References nmsgErrorMsg().

int nmsgListen	(	void **	hndl,
		int	port,
		int	maxConn,
		int	maxData,
		int	prio,
		nmsgConnCB_t	connRtn,
		nmsgDiscCB_t	discRtn,
		nmsgRcveCB_t	rcveRtn,
		void *	uParm
	)

Establish a message server.

This routine establishes a network message server (listener).

Parameters:

	hndl	The address of a pointer to receive the identifying handle for the network listener.
	port	The port number on which to establish the server.
	maxConn	The maximum number of concurrent connections that the server will allow.
	maxData	The maximum number of data bytes that can be transferred in a single message.
	prio	The priority of the listener (server) and receiver tasks, where applicable. If 0, the default value (100) is used.
	connRtn	The address of a routine to be called when a new connection has been made. The connection will be rejected if this routine returns ERROR status.
	discRtn	The address of a routine to be called when a connection is broken.
	rcveRtn	The address of a routine to be called whenever a message is received.
	uParm	A parameter to be passed to the connect, disconnect and receive callback routines.

Return values:

	NMSG_SUCCESS	The connection was established successfully.
	NMSG_NOMEMORY	Insuffucuent memory available.
	NMSG_NOTASKCR	Unable to spawn listener task.
	NMSG_xxx	Various system errors.

References NMSG_MAGIC, NMSG_NOMEMORY, and NMSG_SUCCESS.

int nmsgRemoteIP	(	void *	hndl,
		int *	ip
	)

Get the IP address of the remote end.

This routine returns the IP address of the remote end of a connection. It can be used on either end of a connection.

Parameters:

	hndl	The handle for the connection.
	ip	The addressof an integer to receive the IP address.

Return values:

	NMSG_SUCCESS	Success.
	NMSG_INVHNDL	Invalid network handle.

References NMSG_INVHNDL, NMSG_MAGIC, and NMSG_SUCCESS.

int nmsgSend	(	void *	hndl,
		nmsgBuff_t *	msg
	)

Send a message and return immediately.

This routine sends a message on a network connection and returns without waiting for a reply.

Parameters:

	hndl	The handle for the connection.
	msg	The address of message to be sent. It must be formatted using the nmsgBuff_t structure type.

Return values:

	NMSG_SUCCESS	Success.
	NMSG_INVHNDL	Invalid network handle.
	NMSG_NOTCONN	Not connected to server.
	NMSG_INVSEMA	Invalid semaphore.
	NMSG_DISCONN	Server connection was broken.

References nmsgHead_s::func, nmsgBuff_s::head, nmsgHead_s::leng, nmsgHead_s::magic, NMSG_INVHNDL, NMSG_INVSEMA, NMSG_MAGIC, NMSG_NOTCONN, NMSG_SUCCESS, nmsgHead_s::parm, and nmsgHead_s::stat.

int nmsgSendW	(	void *	hndl,
		nmsgBuff_t *	msg,
		nmsgBuff_t **	replyP,
		nmsgBuff_t *	reply,
		int	maxData
	)

Send a message and receive reply.

This routine sends a message on a network connection and waits for a reply.

Parameters:

	hndl	The handle for the connection.
	msg	The address of message to be sent. It must be formatted using the nmsgBuff_t structure type.
	replyP	The address of a pointer to receive the address of the reply. If a reply area is supplied and it is big enough, this will be the address of this area. Otherwise a sufficiently large reply area is allocated and its address returned here. In this latter case, the memory must be relinquished using free() after it is no longer needed.
	reply	The address of an area to receive the reply to the message, or NULL if no area is to be used.
	maxData	The maximum number of data bytes that can be put into the supplied reply area.

Return values:

	NMSG_SUCCESS	Success.
	NMSG_INVHNDL	Invalid network handle.
	NMSG_NOTCONN	Not connected to server.
	NMSG_INVSEMA	Invalid semaphore.
	NMSG_DISCONN	Server connection was broken.

References nmsgHead_s::func, nmsgBuff_s::head, nmsgHead_s::leng, nmsgHead_s::magic, NMSG_DISCONN, NMSG_INVHNDL, NMSG_INVSEMA, NMSG_MAGIC, NMSG_NOTCONN, NMSG_SUCCESS, nmsgHead_s::parm, and nmsgHead_s::stat.

int nmsgStats	(	void *	hndl,
		nmsgStats_t *	stats
	)

Get connection statistics.

This routine returns a block of connection statistics containing the number of connects, disconnects, messages sent/received, bytes sent and bytes received.

Parameters:

	hndl	The handle for the connection.
	stats	The address of an area to receive the statistics block.

Return values:

	NMSG_SUCCESS	Success.
	NMSG_INVHNDL	Invalid network handle.

References nmsgStats_s::nByteR, nmsgStats_s::nByteS, nmsgStats_s::nConn, nmsgStats_s::nDisc, nmsgStats_s::nMsg, NMSG_INVHNDL, NMSG_MAGIC, and NMSG_SUCCESS.

int nmsgWait	(	void *	hndl,
		nmsgBuff_t **	replyP,
		nmsgBuff_t *	reply,
		int	maxData
	)

Wait for a reply to a sent message.

This routine waits for a reply to a previously sent message.

Parameters:

	hndl	The handle for the connection.
	replyP	The address of a pointer to receive the address of the reply. If a reply area is supplied and it is big enough, this will be the address of this area. Otherwise a sufficiently large reply area is allocated and its address returned here. In this latter case, the memory must be relinquished using free() after it is no longer needed.
	reply	The address of an area to receive the reply to the message, or NULL if no area is to be used.
	maxData	The maximum number of data bytes that can be put into the supplied reply area.

Return values:

	NMSG_SUCCESS	Success.
	NMSG_INVHNDL	Invalid network handle.
	NMSG_NOTCONN	Not connected to server.
	NMSG_INVSEMA	Invalid semaphore.
	NMSG_DISCONN	Server connection was broken.

References NMSG_DISCONN, NMSG_INVHNDL, NMSG_INVSEMA, NMSG_MAGIC, NMSG_NOTCONN, and NMSG_SUCCESS.