-The underlying transport mechanism used to send messages is
-configured in *non-blocking* mode. This means that if a
-message cannot be sent immediately the transport mechanism
-will **not** pause with the assumption that the inability to
-send will clear quickly (within a few milliseconds). This
-means that when the retry loop is completely disabled (set to
-0), that the failure to accept a message for sending by the
-underlying mechanisms (software or hardware) will be reported
-immediately to the user application.
-
-It should be noted that depending on the underlying transport
-mechanism being used, it is extremely likely that retry
-conditions will happen during normal operations. These are
-completely out of RMR's control, and there is nothing that
-RMR can do to avoid or mitigate these other than by allowing
-RMR to retry the send operation, and even then it is possible
-(e.g., during connection reattempts), that a single retry
-loop is not enough to guarantee a successful send.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The rmr_call function returns a pointer to a message buffer
-with the state set to reflect the overall state of call
-processing (see Errors below). In some cases a nil pointer
-will be returned; when this is the case only *errno* will be
-available to describe the reason for failure.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-These values are reflected in the state field of the returned
-message.
-
-
-
-RMR_OK
-
- The call was successful and the message buffer references
- the response message.
-
-
-RMR_ERR_CALLFAILED
-
- The call failed and the value of *errno,* as described
- below, should be checked for the specific reason.
-
-
-The global "variable" *errno* will be set to one of the
-following values if the overall call processing was not
-successful.
-
-
-
-ETIMEDOUT
-
- Too many messages were queued before receiving the
- expected response
-
-
-ENOBUFS
-
- The queued message ring is full, messages were dropped
-
-
-EINVAL
-
- A parameter was not valid
-
-
-EAGAIN
-
- The underlying message system was interrupted or the
- device was busy; the message was **not** sent, and the
- user application should call this function with the
- message again.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-The following code snippet shows one way of using the
-rmr_call function, and illustrates how the transaction ID
-must be set.
-
-
-::
-
- int retries_left = 5; // max retries on dev not available
- int retry_delay = 50000; // retry delay (usec)
- static rmr_mbuf_t* mbuf = NULL; // response msg
- msg_t* pm; // application struct for payload
- // get a send buffer and reference the payload
- mbuf = rmr_alloc_msg( mr, sizeof( pm->req ) );
- pm = (msg_t*) mbuf->payload;
- // generate an xaction ID and fill in payload with data and msg type
- snprintf( mbuf->xaction, RMR_MAX_XID, "%s", gen_xaction() );
- snprintf( pm->req, sizeof( pm->req ), "{ \\"req\\": \\"num users\\"}" );
- mbuf->mtype = MT_REQ;
- msg = rmr_call( mr, msg );
- if( ! msg ) { // probably a timeout and no msg received
- return NULL; // let errno trickle up
- }
- if( mbuf->state != RMR_OK ) {
- while( retries_left-- > 0 && // loop as long as eagain
- errno == EAGAIN &&
- (msg = rmr_call( mr, msg )) != NULL &&
- mbuf->state != RMR_OK ) {
- usleep( retry_delay );
- }
- if( mbuf == NULL || mbuf->state != RMR_OK ) {
- rmr_free_msg( mbuf ); // safe if nil
- return NULL;
- }
- }
- // do something with mbuf
-
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_free_msg(3), rmr_init(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_rcv_msg(3),
-rmr_rcv_specific(3), rmr_rts_msg(3), rmr_ready(3),
-rmr_fib(3), rmr_has_str(3), rmr_set_stimeout(3),
-rmr_tokenise(3), rmr_mk_ring(3), rmr_ring_free(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_close
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- void rmr_close( void* vctx )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_close function closes the listen socket effectively
-cutting the application off. The route table listener is also
-stopped. Calls to rmr_rcv_msg() will fail with unpredictable
-error codes, and calls to rmr_send_msg(), rmr_call(), and
-rmr_rts_msg() will have unknown results.
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3),
-rmr_get_rcvfd(3), rmr_payload_size(3), rmr_send_msg(3),
-rmr_rcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3),
-rmr_ready(3), rmr_fib(3), rmr_has_str(3), rmr_tokenise(3),
-rmr_mk_ring(3), rmr_ring_free(3), rmr_wh_open(3),
-rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_free_msg
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- void rmr_free_msg( rmr_mbuf_t* mbuf );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The message buffer is returned to the pool, or the associated
-memory is released depending on the needs of the underlying
-messaging system. This allows the user application to release
-a buffer that is not going to be used. It is safe to pass a
-nil pointer to this function, and doing so does not result in
-a change to the value of errrno.
-
-After calling, the user application should **not** use any of
-the pointers (transaction ID, or payload) which were
-available.
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_init(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_rcv_msg(3),
-rmr_rcv_specific(3), rmr_rts_msg(3), rmr_ready(3),
-rmr_fib(3), rmr_has_str(3), rmr_tokenise(3), rmr_mk_ring(3),
-rmr_ring_free(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_get_const
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- unsigned char* rmr_get_const();
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_get_const function is a convenience function for
-wrappers which do not have the ability to "compile in" RMR
-constants. The function will build a nil terminated string
-containing JSON which defines the RMR constants that C and Go
-applications have at compile time via the rmr.h header file.
-
-All values are represented as strings and the JSON format is
-illustrated in the following (partial) example:
-
-
-::
-
- {
- "RMR_MAX_XID": "32",
- "RMR_OK": "0",
- "RMR_ERR_BADARG", "1",
- "RMR_ERR_NOENDPT" "2"
- }
-
-
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, a pointer to a string containing the JSON
-defining constant and value pairs. On failure a nil pointer
-is returned.
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr(7)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_get_meid
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- char* rmr_get_meid( rmr_mbuf_t* mbuf, unsigned char* dest )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_get_meid function will copy the managed entity ID
-(meid) field from the message into the *dest* buffer provided
-by the user. The buffer referenced by *dest* is assumed to be
-at least RMR_MAX_MEID bytes in length. If *dest* is NULL,
-then a buffer is allocated (the calling application is
-expected to free when the buffer is no longer needed).
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, a pointer to the extracted string is returned. If
-*dest* was supplied, then this is just a pointer to the
-caller's buffer. If *dest* was NULL, this is a pointer to the
-allocated buffer. If an error occurs, a nil pointer is
-returned and errno is set as described below.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-If an error occurs, the value of the global variable errno
-will be set to one of the following with the indicated
-meaning.
-
-
-
-EINVAL
-
- The message, or an internal portion of the message, was
- corrupted or the pointer was invalid.
-
-
-ENOMEM
-
- A nil pointer was passed for *dest,* however it was not
- possible to allocate a buffer using malloc().
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_bytes2xact(3), rmr_bytes2meid(3),
-rmr_call(3), rmr_free_msg(3), rmr_get_rcvfd(3),
-rmr_get_xact(3), rmr_payload_size(3), rmr_send_msg(3),
-rmr_rcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3),
-rmr_ready(3), rmr_fib(3), rmr_has_str(3), rmr_tokenise(3),
-rmr_mk_ring(3), rmr_ring_free(3), rmr_str2meid(3),
-rmr_str2xact(3), rmr_wh_open(3), rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_get_rcvfd
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- void* rmr_get_rcvfd( void* ctx )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_get_rcvfd function returns a file descriptor which
-may be given to epoll_wait() by an application that wishes to
-use event poll in a single thread rather than block on the
-arrival of a message via calls to rmr_rcv_msg(). When
-epoll_wait() indicates that this file descriptor is ready, a
-call to rmr_rcv_msg() will not block as at least one message
-has been received.
-
-The context (ctx) pointer passed in is the pointer returned
-by the call to rmr_init().
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The rmr_get_rcvfd function returns a file descriptor greater
-or equal to 0 on success and -1 on error.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-The following error values are specifically set by this RMR
-function. In some cases the error message of a system call is
-propagated up, and thus this list might be incomplete.
-
-
-EINVAL
-
- The use of this function is invalid in this environment.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-The following short code bit illustrates the use of this
-function. Error checking has been omitted for clarity.
-
-
-::
-
- #include <stdio.h>
- #include <stdlib.h>
- #include <sys/epoll.h>
- #include <rmr/rmr.h>
- int main() {
- int rcv_fd; // pollable fd
- void* mrc; //msg router context
- struct epoll_event events[10]; // support 10 events to poll
- struct epoll_event epe; // event definition for event to listen to
- int ep_fd = -1;
- rmr_mbuf_t* msg = NULL;
- int nready;
- int i;
- int norm_msg_size = 1500; // 95% messages are less than this
- mrc = rmr_init( "43086", norm_msg_size, RMRFL_NONE );
- rcv_fd = rmr_get_rcvfd( mrc );
- ep_fd = epoll_create1( 0 ); // initialise epoll environment
- epe.events = EPOLLIN;
- epe.data.fd = rcv_fd;
- epoll_ctl( ep_fd, EPOLL_CTL_ADD, rcv_fd, &epe ); // add our info to the mix
- while( 1 ) {
- nready = epoll_wait( ep_fd, events, 10, -1 ); // -1 == block forever (no timeout)
- for( i = 0; i < nready && i < 10; i++ ) { // loop through to find what is ready
- if( events[i].data.fd == rcv_fd ) { // RMR has something
- msg = rmr_rcv_msg( mrc, msg );
- if( msg ) {
- // do something with msg
- }
- }
- // check for other ready fds....
- }
- }
- }
-
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_rcv_msg(3),
-rmr_rcv_specific(3), rmr_rts_msg(3), rmr_ready(3),
-rmr_fib(3), rmr_has_str(3), rmr_tokenise(3), rmr_mk_ring(3),
-rmr_ring_free(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_get_src
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- unsigned char* rmr_get_src( rmr_mbuf_t* mbuf, unsigned char* dest )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_get_src function will copy the *source* information
-from the message to a buffer (dest) supplied by the user. In
-an RMr message, the source is the sender's information that
-is used for return to sender function calls, and is generally
-the hostname and port in the form *name*. The source might be
-an IP address port combination; the data is populated by the
-sending process and the only requirement is that it be
-capable of being used to start a TCP session with the sender.
-
-The maximum size allowed by RMr is 64 bytes (including the
-nil string terminator), so the user must ensure that the
-destination buffer given is at least 64 bytes.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, a pointer to the destination buffer is given as a
-convenience to the user programme. On failure, a nil pointer
-is returned and the value of errno is set.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-If an error occurs, the value of the global variable errno
-will be set to one of the following with the indicated
-meaning.
-
-
-
-EINVAL
-
- The message, or an internal portion of the message, was
- corrupted or the pointer was invalid.
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_bytes2xact(3), rmr_bytes2meid(3),
-rmr_call(3), rmr_free_msg(3), rmr_get_rcvfd(3),
-rmr_get_srcip(3), rmr_payload_size(3), rmr_send_msg(3),
-rmr_rcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3),
-rmr_ready(3), rmr_fib(3), rmr_has_str(3), rmr_tokenise(3),
-rmr_mk_ring(3), rmr_ring_free(3), rmr_str2meid(3),
-rmr_str2xact(3), rmr_wh_open(3), rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_get_srcip
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- unsigned char* rmr_get_srcip( rmr_mbuf_t* mbuf, unsigned char* dest )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_get_srcip function will copy the *source IP address*
-from the message to a buffer (dest) supplied by the user. In
-an RMr message, the source IP address is the sender's
-information that is used for return to sender function calls;
-this function makes it available to the user application. The
-address is maintained as IP:port where *IP* could be either
-an IPv6 or IPv4 address depending on what was provided by the
-sending application.
-
-The maximum size allowed by RMr is 64 bytes (including the
-nil string terminator), so the user must ensure that the
-destination buffer given is at least 64 bytes. The user
-application should use the RMr constant RMR_MAX_SRC to ensure
-that the buffer supplied is large enough, and to protect
-against future RMr enhancements which might increase the
-address buffer size requirement.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, a pointer to the destination buffer is given as a
-convenience to the user programme. On failure, a nil pointer
-is returned and the value of errno is set.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-If an error occurs, the value of the global variable errno
-will be set to one of the following with the indicated
-meaning.
-
-
-
-EINVAL
-
- The message, or an internal portion of the message, was
- corrupted or the pointer was invalid.
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_bytes2xact(3), rmr_bytes2meid(3),
-rmr_call(3), rmr_free_msg(3), rmr_get_rcvfd(3),
-rmr_get_src(3), rmr_payload_size(3), rmr_send_msg(3),
-rmr_rcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3),
-rmr_ready(3), rmr_fib(3), rmr_has_str(3), rmr_tokenise(3),
-rmr_mk_ring(3), rmr_ring_free(3), rmr_str2meid(3),
-rmr_str2xact(3), rmr_wh_open(3), rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_get_trace
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- int rmr_get_trace( rmr_mbuf_t* mbuf, unsigned char* dest, int size )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_get_trace function will copy the trace information
-from the message into the user's allocated memory referenced
-by dest. The size parameter is assumed to be the maximum
-number of bytes which can be copied (size of the destination
-buffer).
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, the number of bytes actually copied is returned.
-If the return value is 0, no bytes copied, then the reason
-could be that the message pointer was nil, or the size
-parameter was <= 0.
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_tralloc_msg(3), rmr_bytes2xact(3),
-rmr_bytes2meid(3), rmr_call(3), rmr_free_msg(3),
-rmr_get_rcvfd(3), rmr_get_trlen(3), rmr_init(3),
-rmr_init_trace(3), rmr_payload_size(3), rmr_send_msg(3),
-rmr_rcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3),
-rmr_ready(3), rmr_fib(3), rmr_has_str(3), rmr_tokenise(3),
-rmr_mk_ring(3), rmr_ring_free(3), rmr_str2meid(3),
-rmr_str2xact(3), rmr_wh_open(3), rmr_wh_send_msg(3),
-rmr_set_trace(3), rmr_trace_ref(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_get_trlen
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- int rmr_get_trlen( rmr_mbuf_t* msg );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-Given a message buffer, this function returns the amount of
-space (bytes) that have been allocated for trace data. If no
-trace data has been allocated, then 0 is returned.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The number of bytes allocated for trace information in the
-given message.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-
-
-INVAL
-
- Parameter(s) passed to the function were not valid.
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3),
-rmr_get_trace(3), rmr_init(3), rmr_init_trace(3),
-rmr_send_msg(3), rmr_rcv_msg(3), rmr_rcv_specific(3),
-rmr_rts_msg(3), rmr_ready(3), rmr_fib(3), rmr_has_str(3),
-rmr_tokenise(3), rmr_mk_ring(3), rmr_ring_free(3),
-rmr_set_trace(3), rmr_tralloc_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_get_xact
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- char* rmr_get_xact( rmr_mbuf_t* mbuf, unsigned char* dest )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_get_xact function will copy the transaction field
-from the message into the *dest* buffer provided by the user.
-The buffer referenced by *dest* is assumed to be at least
-RMR_MAX_XID bytes in length. If *dest* is NULL, then a buffer
-is allocated (the calling application is expected to free
-when the buffer is no longer needed).
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, a pointer to the extracted string is returned. If
-*dest* was supplied, then this is just a pointer to the
-caller's buffer. If *dest* was NULL, this is a pointer to the
-allocated buffer. If an error occurs, a nil pointer is
-returned and errno is set as described below.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-If an error occurs, the value of the global variable errno
-will be set to one of the following with the indicated
-meaning.
-
-
-
-EINVAL
-
- The message, or an internal portion of the message, was
- corrupted or the pointer was invalid.
-
-
-ENOMEM
-
- A nil pointer was passed for *dest,* however it was not
- possible to allocate a buffer using malloc().
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_bytes2xact(3), rmr_bytes2meid(3),
-rmr_call(3), rmr_free_msg(3), rmr_get_rcvfd(3),
-rmr_get_meid(3), rmr_payload_size(3), rmr_send_msg(3),
-rmr_rcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3),
-rmr_ready(3), rmr_fib(3), rmr_has_str(3), rmr_tokenise(3),
-rmr_mk_ring(3), rmr_ring_free(3), rmr_str2meid(3),
-rmr_str2xact(3), rmr_wh_open(3), rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_init
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- void* rmr_init( char* proto_port, int norm_msg_size, int flags );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_init function prepares the environment for sending
-and receiving messages. It does so by establishing a worker
-thread (pthread) which subscribes to a route table generator
-which provides the necessary routing information for the RMR
-library to send messages.
-
-*Port* is used to listen for connection requests from other
-RMR based applications. The *norm_msg_size* parameter is used
-to allocate receive buffers and should be set to what the
-user application expects to be a size which will hold the
-vast majority of expected messages. When computing the size,
-the application should consider the usual payload size
-**and** the maximum trace data size that will be used. This
-value is also used as the default message size when
-allocating message buffers (when a zero size is given to
-rmr_alloc_msg(); see the rmr_alloc_msg() manual page).
-Messages arriving which are longer than the given normal size
-will cause RMR to allocate a new buffer which is large enough
-for the arriving message.
-
-Starting with version 3.8.0 RMR no longer places a maximum
-buffer size for received messages. The underlying system
-memory manager might impose such a limit and the attempt to
-allocate a buffer larger than that limit will likely result
-in an application abort. Other than the potential performance
-impact from extra memory allocation and release, there is no
-penality to the user programme for specifyning a normal
-buffer size which is usually smaller than received buffers.
-Similarly, the only penality to the application for over
-specifying the normal buffer size might be a larger memory
-footprint.
-
-*Flags* allows for selection of some RMr options at the time
-of initialisation. These are set by ORing RMRFL constants
-from the RMr header file. Currently the following flags are
-supported:
-
-
-
-RMRFL_NONE
-
- No flags are set.
-
-
-RMRFL_NOTHREAD
-
- The route table collector thread is not to be started.
- This should only be used by the route table generator
- application if it is based on RMr.
-
-
-RMRFL_MTCALL
-
- Enable multi-threaded call support.
-
-
-RMRFL_NOLOCK
-
- Some underlying transport providers (e.g. SI95) enable
- locking to be turned off if the user application is single
- threaded, or otherwise can guarantee that RMR functions
- will not be invoked concurrently from different threads.
- Turning off locking can help make message receipt more
- efficient. If this flag is set when the underlying
- transport does not support disabling locks, it will be
- ignored.
-
-
-Multi-threaded Calling
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The support for an application to issue a *blocking call* by
-the rmr_call() function was limited such that only user
-applications which were operating in a single thread could
-safely use the function. Further, timeouts were message count
-based and not time unit based. Multi-threaded call support
-adds the ability for a user application with multiple threads
-to invoke a blocking call function with the guarantee that
-the correct response message is delivered to the thread. The
-additional support is implemented with the *rmr_mt_call()*
-and *rmr_mt_rcv()* function calls.
-
-Multi-threaded call support requires the user application to
-specifically enable it when RMr is initialised. This is
-necessary because a second, dedicated, receiver thread must
-be started, and requires all messages to be examined and
-queued by this thread. The additional overhead is minimal,
-queuing information is all in the RMr message header, but as
-an additional process is necessary the user application must
-"opt in" to this approach.
-
-
-ENVIRONMENT
---------------------------------------------------------------------------------------------
-
-As a part of the initialisation process rmr_init reads
-environment variables to configure itself. The following
-variables are used if found.
-
-
-
-RMR_ASYNC_CONN
-
- Allows the async connection mode to be turned off (by
- setting the value to 0). When set to 1, or missing from
- the environment, RMR will invoke the connection interface
- in the transport mechanism using the non-blocking (async)
- mode. This will likely result in many "soft failures"
- (retry) until the connection is established, but allows
- the application to continue unimpeded should the
- connection be slow to set up.
-
-
-RMR_BIND_IF
-
- This provides the interface that RMR will bind listen
- ports to, allowing for a single interface to be used
- rather than listening across all interfaces. This should
- be the IP address assigned to the interface that RMR
- should listen on, and if not defined RMR will listen on
- all interfaces.
-
-
-RMR_CTL_PORT
-
- This variable defines the port that RMR should open for
- communications with Route Manager, and other RMR control
- applications. If not defined, the port 4561 is assumed.
-
- Previously, the RMR_RTG_SVC (route table generator service
- port) was used to define this port. However, a future
- version of Route Manager will require RMR to connect and
- request tables, thus that variable is now used to supply
- the Route Manager's well-known address and port.
-
- To maintain backwards compatibility with the older Route
- Manager versions, the presence of this variable in the
- environment will shift RMR's behaviour with respect to the
- default value used when RMR_RTG_SVC is **not** defined.
-
- When RMR_CTL_PORT is **defined:** RMR assumes that Route
- Manager requires RMR to connect and request table updates
- is made, and the default well-known address for Route
- manager is used (routemgr:4561).
-
- When RMR_CTL_PORT is **undefined:** RMR assumes that Route
- Manager will connect and push table updates, thus the
- default listen port (4561) is used.
-
- To avoid any possible misinterpretation and/or incorrect
- assumptions on the part of RMR, it is recommended that
- both the RMR_CTL_PORT and RMR_RTG_SVC be defined. In the
- case where both variables are defined, RMR will behave
- exactly as is communicated with the variable's values.
-
-
-RMR_RTG_SVC
-
- The value of this variable depends on the Route Manager in
- use.
-
- When the Route Manager is expecting to connect to an xAPP
- and push route tables, this variable must indicate the
- port which RMR should use to listen for these connections.
-
- When the Route Manager is expecting RMR to connect and
- request a table update during initialisation, the variable
- should be the host of the Route Manager process.
-
- The RMR_CTL_PORT variable (added with the support of
- sending table update requests to Route manager), controls
- the behaviour if this variable is not set. See the
- description of that variable for details.
-
-
-RMR_HR_LOG
-
- By default RMR writes messages to standard error
- (incorrectly referred to as log messages) in human
- readable format. If this environment variable is set to 0,
- the format of standard error messages might be written in
- some format not easily read by humans. If missing, a value
- of 1 is assumed.
-
-
-RMR_LOG_VLEVEL
-
- This is a numeric value which corresponds to the verbosity
- level used to limit messages written to standard error.
- The lower the number the less chatty RMR functions are
- during execution. The following is the current
- relationship between the value set on this variable and
- the messages written:
-
-
-0
-
- Off; no messages of any sort are written.
-
-
-1
-
- Only critical messages are written (default if this
- variable does not exist)
-
-
-2
-
- Errors and all messages written with a lower value.
-
-
-3
-
- Warnings and all messages written with a lower value.
-
-
-4
-
- Informational and all messages written with a lower
- value.
-
-
-5
-
- Debugging mode -- all messages written, however this
- requires RMR to have been compiled with debugging
- support enabled.
-
-
-
-RMR_RTG_ISRAW
-
- **Deprecated.** Should be set to 1 if the route table
- generator is sending "plain" messages (not using RMR to
- send messages), 0 if the RTG is using RMR to send. The
- default is 1 as we don't expect the RTG to use RMR.
-
- This variable is only recognised when using the NNG
- transport library as it is not possible to support NNG
- "raw" communications with other transport libraries. It is
- also necessary to match the value of this variable with
- the capabilities of the Route Manager; at some point in
- the future RMR will assume that all Route Manager messages
- will arrive via an RMR connection and will ignore this
- variable.
-
-RMR_SEED_RT
-
- This is used to supply a static route table which can be
- used for debugging, testing, or if no route table
- generator process is being used to supply the route table.
- If not defined, no static table is used and RMR will not
- report *ready* until a table is received. The static route
- table may contain both the route table (between newrt
- start and end records), and the MEID map (between meid_map
- start and end records).
-
-RMR_SRC_ID
-
- This is either the name or IP address which is placed into
- outbound messages as the message source. This will used
- when an RMR based application uses the rmr_rts_msg()
- function to return a response to the sender. If not
- supplied RMR will use the hostname which in some container
- environments might not be routable.
-
- The value of this variable is also used for Route Manager
- messages which are sent via an RMR connection.
-
-RMR_VCTL_FILE
-
- This supplies the name of a verbosity control file. The
- core RMR functions do not produce messages unless there is
- a critical failure. However, the route table collection
- thread, not a part of the main message processing
- component, can write additional messages to standard
- error. If this variable is set, RMR will extract the
- verbosity level for these messages (0 is silent) from the
- first line of the file. Changes to the file are detected
- and thus the level can be changed dynamically, however RMR
- will only suss out this variable during initialisation, so
- it is impossible to enable verbosity after startup.
-
-RMR_WARNINGS
-
- If set to 1, RMR will write some warnings which are
- non-performance impacting. If the variable is not defined,
- or set to 0, RMR will not write these additional warnings.
-
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The rmr_init function returns a void pointer (a contex if you
-will) that is passed as the first parameter to nearly all
-other RMR functions. If rmr_init is unable to properly
-initialise the environment, NULL is returned and errno is set
-to an appropriate value.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-The following error values are specifically set by this RMR
-function. In some cases the error message of a system call is
-propagated up, and thus this list might be incomplete.
-
-
-ENOMEM
-
- Unable to allocate memory.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-
-::
-
- void* uh;
- rmr_mbuf* buf = NULL;
- uh = rmr_init( "43086", 4096, 0 );
- buf = rmr_rcv_msg( uh, buf );
-
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3),
-rmr_get_rcvfd(3), rmr_mt_call(3), rmr_mt_rcv(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_rcv_msg(3),
-rmr_rcv_specific(3), rmr_rts_msg(3), rmr_ready(3),
-rmr_fib(3), rmr_has_str(3), rmr_tokenise(3), rmr_mk_ring(3),
-rmr_ring_free(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_init_trace
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- void* rmr_init_trace( void* ctx )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_init_trace function establishes the default trace
-space placed in each message buffer allocated with
-rmr_alloc_msg(). If this function is never called, then no
-trace space is allocated by default into any message buffer.
-
-Trace space allows the user application to pass some trace
-token, or other data with the message, but outside of the
-payload. Trace data may be added to any message with
-rmr_set_trace(), and may be extracted from a message with
-rmr_get_trace(). The number of bytes that a message contains
-for/with trace data can be determined by invoking
-rmr_get_trlen().
-
-This function may be safely called at any time during the
-life of the user programme to (re)set the default trace space
-reserved. If the user programme needs to allocate a message
-with trace space of a different size than is allocated by
-default, without fear of extra overhead of reallocating a
-message later, the rmr_tralloc_msg() function can be used.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-A value of 1 is returned on success, and 0 on failure. A
-failure indicates that the RMr context (a void pointer passed
-to this function was not valid.
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_tr_alloc_msg(3), rmr_call(3),
-rmr_free_msg(3), rmr_get_rcvfd(3), rmr_get_trace(3),
-rmr_get_trlen(3), rmr_payload_size(3), rmr_send_msg(3),
-rmr_rcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3),
-rmr_ready(3), rmr_fib(3), rmr_has_str(3), rmr_tokenise(3),
-rmr_mk_ring(3), rmr_ring_free(3), rmr_set_trace(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_mt_call
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- extern rmr_mbuf_t* rmr_mt_call( void* vctx, rmr_mbuf_t* msg, int id, int timeout );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_mt_call function sends the user application message
-to a remote endpoint, and waits for a corresponding response
-message before returning control to the user application. The
-user application supplies a completed message buffer, as it
-would for a rmr_send_msg call, but unlike with a send, the
-buffer returned will have the response from the application
-that received the message. The thread invoking the
-*rmr_mt_call()* will block until a message arrives or until
-*timeout* milliseconds has passed; which ever comes first.
-Using a timeout value of zero (0) will cause the thread to
-block without a timeout.
-
-The *id* supplied as the third parameter is an integer in the
-range of 2 through 255 inclusive. This is a caller defined
-"thread number" and is used to match the response message
-with the correct user application thread. If the ID value is
-not in the proper range, the attempt to make the call will
-fail.
-
-Messages which are received while waiting for the response
-are queued on a *normal* receive queue and will be delivered
-to the user application with the next invocation of
-*rmr_mt_rcv()* or *rmr_rvv_msg().* by RMR, and are returned
-to the user application when rmr_rcv_msg is invoked. These
-messages are returned in the order received, one per call to
-rmr_rcv_msg.
-
-The Transaction ID
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The user application is responsible for setting the value of
-the transaction ID field before invoking *rmr_mt_call.* The
-transaction ID is a RMR_MAX_XID byte field that is used to
-match the response message when it arrives. RMR will compare
-**all** of the bytes in the field, so the caller must ensure
-that they are set correctly to avoid missing the response
-message. The application which returns the response message
-is also expected to ensure that the return buffer has the
-matching transaction ID. This can be done transparently if
-the application uses the *rmr_rts_msg()* function and does
-not adjust the transaction ID.
-
-Retries
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The send operations in RMR will retry *soft* send failures
-until one of three conditions occurs:
-
-
-
-1.
-
- The message is sent without error
-
-
-2.
-
- The underlying transport reports a *hard* failure
-
-
-3.
-
- The maximum number of retry loops has been attempted
-
-
-A retry loop consists of approximately 1000 send attempts
-**without** any intervening calls to *sleep()* or *usleep().*
-The number of retry loops defaults to 1, thus a maximum of
-1000 send attempts is performed before returning to the user
-application. This value can be set at any point after RMr
-initialisation using the *rmr_set_stimeout()* function
-allowing the user application to completely disable retires
-(set to 0), or to increase the number of retry loops.
-
-Transport Level Blocking
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The underlying transport mechanism used to send messages is
-configured in *non-blocking* mode. This means that if a
-message cannot be sent immediately the transport mechanism
-will **not** pause with the assumption that the inability to
-send will clear quickly (within a few milliseconds). This
-means that when the retry loop is completely disabled (set to
-0), that the failure to accept a message for sending by the
-underlying mechanisms (software or hardware) will be reported
-immediately to the user application.
-
-It should be noted that depending on the underlying transport
-mechanism being used, it is extremely likely that retry
-conditions will happen during normal operations. These are
-completely out of RMR's control, and there is nothing that
-RMR can do to avoid or mitigate these other than by allowing
-RMR to retry the send operation, and even then it is possible
-(e.g., during connection reattempts), that a single retry
-loop is not enough to guarantee a successful send.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The rmr_mt_call function returns a pointer to a message
-buffer with the state set to reflect the overall state of
-call processing. If the state is RMR_OK then the buffer
-contains the response message; otherwise the state indicates
-the error encountered while attempting to send the message.
-
-If no response message is received when the timeout period
-has expired, a nil pointer will be returned (NULL).
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-These values are reflected in the state field of the returned
-message.
-
-
-
-RMR_OK
-
- The call was successful and the message buffer references
- the response message.
-
-
-RMR_ERR_BADARG
-
- An argument passed to the function was invalid.
-
-
-RMR_ERR_CALLFAILED
-
- The call failed and the value of *errno,* as described
- below, should be checked for the specific reason.
-
-
-RMR_ERR_NOENDPT
-
- An endpoint associated with the message type could not be
- found in the route table.
-
-
-RMR_ERR_RETRY
-
- The underlying transport mechanism was unable to accept
- the message for sending. The user application can retry
- the call operation if appropriate to do so.
-
-
-The global "variable" *errno* will be set to one of the
-following values if the overall call processing was not
-successful.
-
-
-
-ETIMEDOUT
-
- Too many messages were queued before receiving the
- expected response
-
-
-ENOBUFS
-
- The queued message ring is full, messages were dropped
-
-
-EINVAL
-
- A parameter was not valid
-
-
-EAGAIN
-
- The underlying message system wsa interrupted or the
- device was busy; the message was **not** sent, and user
- application should call this function with the message
- again.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-The following code bit shows one way of using the rmr_mt_call
-function, and illustrates how the transaction ID must be set.
-
-
-::
-
- int retries_left = 5; // max retries on dev not available
- static rmr_mbuf_t* mbuf = NULL; // response msg
- msg_t* pm; // appl message struct (payload)
- // get a send buffer and reference the payload
- mbuf = rmr_alloc_msg( mr, sizeof( pm->req ) );
- pm = (msg_t*) mbuf->payload;
- // generate an xaction ID and fill in payload with data and msg type
- rmr_bytes2xact( mbuf, xid, RMR_MAX_XID );
- snprintf( pm->req, sizeof( pm->req ), "{ \\"req\\": \\"num users\\"}" );
- mbuf->mtype = MT_USR_RESP;
- msg = rmr_mt_call( mr, msg, my_id, 100 ); // wait up to 100ms
- if( ! msg ) { // probably a timeout and no msg received
- return NULL; // let errno trickle up
- }
- if( mbuf->state != RMR_OK ) {
- while( retries_left-- > 0 && // loop as long as eagain
- mbuf->state == RMR_ERR_RETRY &&
- (msg = rmr_mt_call( mr, msg )) != NULL &&
- mbuf->state != RMR_OK ) {
- usleep( retry_delay );
- }
- if( mbuf == NULL || mbuf->state != RMR_OK ) {
- rmr_free_msg( mbuf ); // safe if nil
- return NULL;
- }
- }
- // do something with mbuf
-
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_free_msg(3), rmr_init(3),
-rmr_mt_rcv(3), rmr_payload_size(3), rmr_send_msg(3),
-rmr_rcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3),
-rmr_ready(3), rmr_fib(3), rmr_has_str(3),
-rmr_set_stimeout(3), rmr_tokenise(3), rmr_mk_ring(3),
-rmr_ring_free(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_mt_rcv
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- rmr_mbuf_t* rmr_mt_rcv( void* vctx, rmr_mbuf_t* old_msg, int timeout );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_mt_rcv function blocks until a message is received,
-or the timeout period (milliseconds) has passed. The result
-is an RMr message buffer which references a received message.
-In the case of a timeout the state will be reflected in an
-"empty buffer" (if old_msg was not nil, or simply with the
-return of a nil pointer. If a timeout value of zero (0) is
-given, then the function will block until the next message
-received.
-
-The *vctx* pointer is the pointer returned by the rmr_init
-function. *Old_msg* is a pointer to a previously used message
-buffer or NULL. The ability to reuse message buffers helps to
-avoid alloc/free cycles in the user application. When no
-buffer is available to supply, the receive function will
-allocate one.
-
-The *old_msg* parameter allows the user to pass a previously
-generated RMR message back to RMR for reuse. Optionally, the
-user application may pass a nil pointer if no reusable
-message is available. When a timeout occurs, and old_msg was
-not nil, the state will be returned by returning a pointer to
-the old message with the state set.
-
-It is possible to use the *rmr_rcv_msg()* function instead of
-this function. Doing so might be advantageous if the user
-programme does not always start the multi-threaded mode and
-the use of *rmr_rcv_msg()* would make the flow of the code
-more simple. The advantages of using this function are the
-ability to set a timeout without using epoll, and a small
-performance gain (if multi-threaded mode is enabled, and the
-*rmr_rcv_msg()* function is used, it simply invokes this
-function without a timeout value, thus there is the small
-cost of a second call that results). Similarly, the
-*rmr_torcv_msg()* call can be used when in multi-threaded
-mode with the same "pass through" overhead to using this
-function directly.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-When a message is received before the timeout period expires,
-a pointer to the RMr message buffer which describes the
-message is returned. This will, with a high probability, be a
-different message buffer than *old_msg;* the user application
-should not continue to use *old_msg* after it is passed to
-this function.
-
-In the event of a timeout the return value will be the old
-msg with the state set, or a nil pointer if no old message
-was provided.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-The *state* field in the message buffer will be set to one of
-the following values:
-
-
-
-RMR_OK
-
- The message was received without error.
-
-
-RMR_ERR_BADARG
-
- A parameter passed to the function was not valid (e.g. a
- nil pointer). indicate either RMR_OK or RMR_ERR_EMPTY if
- an empty message was received.
-
-
-RMR_ERR_EMPTY
-
- The message received had no associated data. The length of
- the message will be 0.
-
-
-RMR_ERR_NOTSUPP
-
- The multi-threaded option was not enabled when RMr was
- initialised. See the man page for *rmr_init()* for
- details.
-
-
-RMR_ERR_RCVFAILED
-
- A hard error occurred preventing the receive from
- completing.
-
-When a nil pointer is returned, or any other state value was
-set in the message buffer, errno will be set to one of the
-following:
-
-
-
-INVAL
-
- Parameter(s) passed to the function were not valid.
-
-
-EBADF
-
- The underlying message transport is unable to process the
- request.
-
-
-ENOTSUP
-
- The underlying message transport is unable to process the
- request.
-
-
-EFSM
-
- The underlying message transport is unable to process the
- request.
-
-
-EAGAIN
-
- The underlying message transport is unable to process the
- request.
-
-
-EINTR
-
- The underlying message transport is unable to process the
- request.
-
-
-ETIMEDOUT
-
- The underlying message transport is unable to process the
- request.
-
-
-ETERM
-
- The underlying message transport is unable to process the
- request.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-
-
-::
-
- rmr_mbuf_t* mbuf = NULL; // received msg
- msg = rmr_mt_recv( mr, mbuf, 100 ); // wait up to 100ms
- if( msg != NULL ) {
- switch( msg->state ) {
- case RMR_OK:
- printf( "got a good message\\n" );
- break;
- case RMR_ERR_EMPTY:
- printf( "received timed out\\n" );
- break;
- default:
- printf( "receive error: %d\\n", mbuf->state );
- break;
- }
- } else {
- printf( "receive timeout (nil)\\n" );
- }
-
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3),
-rmr_get_rcvfd(3), rmr_init(3), rmr_mk_ring(3),
-rmr_mt_call(3), rmr_payload_size(3), rmr_send_msg(3),
-rmr_torcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3),
-rmr_ready(3), rmr_ring_free(3), rmr_torcv_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_payload_size
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- int rmr_payload_size( rmr_mbuf_t* msg );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-Given a message buffer, this function returns the amount of
-space (bytes) available for the user application to consume
-in the message payload. This is different than the message
-length available as a field in the message buffer.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The number of bytes available in the payload.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-
-
-INVAL
-
- Parameter(s) passed to the function were not valid.
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3), rmr_init(3),
-rmr_send_msg(3), rmr_rcv_msg(3), rmr_rcv_specific(3),
-rmr_rts_msg(3), rmr_ready(3), rmr_fib(3), rmr_has_str(3),
-rmr_tokenise(3), rmr_mk_ring(3), rmr_ring_free(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_rcv_msg
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- rmr_mbuf_t* rmr_rcv_msg( void* vctx, rmr_mbuf_t* old_msg );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_rcv_msg function blocks until a message is received,
-returning the message to the caller via a pointer to a
-rmr_mbuf_t structure type. If messages were queued while
-waiting for the response to a previous invocation of
-rmr_call, the oldest message is removed from the queue and
-returned without delay.
-
-The *vctx* pointer is the pointer returned by the rmr_init
-function. *Old_msg* is a pointer to a previously used message
-buffer or NULL. The ability to reuse message buffers helps to
-avoid alloc/free cycles in the user application. When no
-buffer is available to supply, the receive function will
-allocate one.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The function returns a pointer to the rmr_mbuf_t structure
-which references the message information (state, length,
-payload), or a nil pointer in the case of an extreme error.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-The *state* field in the message buffer will indicate RMR_OK
-when the message receive process was successful and the
-message can be used by the caller. Depending on the
-underlying transport mechanism, one of the following RMR
-error stats may be returned:
-
-
-
-RMR_ERR_EMPTY
-
- The message received had no payload, or was completely
- empty.
-
-
-RMR_ERR_TIMEOUT
-
- For some transport mechanisms, or if reading the receive
- queue from multiple threads, it is possible for one thread
- to find no data waiting when it queries the queue. When
- this state is reported, the message buffer does not
- contain message data and the user application should
- reinvoke the receive function.
-
-
-When an RMR error state is reported, the underlying errno
-value might provide more information. The following is a list
-of possible values that might accompany the states listed
-above:
-
-RMR_ERR_EMPTY if an empty message was received. If a nil
-pointer is returned, or any other state value was set in the
-message buffer, errno will be set to one of the following:
-
-
-
-INVAL
-
- Parameter(s) passed to the function were not valid.
-
-
-EBADF
-
- The underlying message transport is unable to process the
- request.
-
-
-ENOTSUP
-
- The underlying message transport is unable to process the
- request.
-
-
-EFSM
-
- The underlying message transport is unable to process the
- request.
-
-
-EAGAIN
-
- The underlying message transport is unable to process the
- request.
-
-
-EINTR
-
- The underlying message transport is unable to process the
- request.
-
-
-ETIMEDOUT
-
- The underlying message transport is unable to process the
- request.
-
-
-ETERM
-
- The underlying message transport is unable to process the
- request.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3),
-rmr_get_rcvfd(3), rmr_init(3), rmr_mk_ring(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_torcv_msg(3),
-rmr_rcv_specific(3), rmr_rts_msg(3), rmr_ready(3),
-rmr_ring_free(3), rmr_torcv_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_ready
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- int rmr_ready( void* vctx );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_ready function checks to see if a routing table has
-been successfully received and installed. The return value
-indicates the state of readiness.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-A return value of 1 (true) indicates that the routing table
-is in place and attempts to send messages can be made. When 0
-is returned (false) the routing table has not been received
-and thus attempts to send messages will fail with *no
-endpoint* errors.
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3), rmr_init(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_rcv_msg(3),
-rmr_rcv_specific(3), rmr_rts_msg(3), rmr_fib(3),
-rmr_has_str(3), rmr_tokenise(3), rmr_mk_ring(3),
-rmr_ring_free(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_realloc_payload
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- extern rmr_mbuf_t* rmr_realloc_payload( rmr_mbuf_t* msg, int new_len, int copy, int clone );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_realloc_payload function will return a pointer to an
-RMR message buffer struct (rmr_mbuf_t) which has a payload
-large enough to accomodate *new_len* bytes. If necessary, the
-underlying payload is reallocated, and the bytes from the
-original payload are copied if the *copy* parameter is true
-(1). If the message passed in has a payload large enough,
-there is no additional memory allocation and copying.
-
-Cloning The Message Buffer
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-This function can also be used to generate a separate copy of
-the original message, with the desired payload size, without
-destroying the original message buffer or the original
-payload. A standalone copy is made only when the *clone*
-parameter is true (1). When cloning, the payload is copied to
-the cloned message **only** if the *copy* parameter is true.
-
-Message Buffer Metadata
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The metadata in the original message buffer (message type,
-subscription ID, and payload length) will be preserved if the
-*copy* parameter is true. When this parameter is not true
-(0), then these values are set to the uninitialised value
-(-1) for type and ID, and the length is set to 0.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The rmr_realloc_payload function returns a pointer to the
-message buffer with the payload which is large enough to hold
-*new_len* bytes. If the *clone* option is true, this will be
-a pointer to the newly cloned message buffer; the original
-message buffer pointer may still be used to reference that
-message. It is the calling application's responsibility to
-free the memory associateed with both messages using the
-rmr_free_msg() function.
-
-When the *clone* option is not used, it is still good
-practice by the calling application to capture and use this
-reference as it is possible that the message buffer, and not
-just the payload buffer, was reallocated. In the event of an
-error, a nil pointer will be returned and the value of
-*errno* will be set to reflect the problem.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-These value of *errno* will reflect the error condition if a
-nil pointer is returned:
-
-
-
-ENOMEM
-
- Memory allocation of the new payload failed.
-
-
-EINVAL
-
- The pointer passed in was nil, or refrenced an invalid
- message, or the required length was not valid.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-The following code bit illustrates how this function can be
-used to reallocate a buffer for a return to sender
-acknowledgement message which is larger than the message
-received.
-
-
-::
-
- if( rmr_payload_size( msg ) < ack_sz ) { // received message too small for ack
- msg = rmr_realloc_payload( msg, ack_sz, 0, 0 ); // reallocate the message with a payload big enough
- if( msg == NULL ) {
- fprintf( stderr, "[ERR] realloc returned a nil pointer: %s\\n", strerror( errno ) );
- } else {
- // populate and send ack message
- }
- }
-
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_free_msg(3), rmr_init(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_rcv_msg(3),
-rmr_rcv_specific(3), rmr_rts_msg(3), rmr_ready(3),
-rmr_fib(3), rmr_has_str(3), rmr_set_stimeout(3),
-rmr_tokenise(3), rmr_mk_ring(3), rmr_ring_free(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_rts_msg
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- rmr_mbuf_t* rmr_rts_msg( void* vctx, rmr_mbuf_t* msg );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_rts_msg function sends a message returning it to the
-endpoint which sent the message rather than selecting an
-endpoint based on the message type and routing table. Other
-than this small difference, the behaviour is exactly the same
-as rmr_send_msg.
-
-Retries
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The send operations in RMR will retry *soft* send failures
-until one of three conditions occurs:
-
-
-
-1.
-
- The message is sent without error
-
-
-2.
-
- The underlying transport reports a *hard* failure
-
-
-3.
-
- The maximum number of retry loops has been attempted
-
-
-A retry loop consists of approximately 1000 send attempts
-**without** any intervening calls to *sleep()* or *usleep().*
-The number of retry loops defaults to 1, thus a maximum of
-1000 send attempts is performed before returning to the user
-application. This value can be set at any point after RMr
-initialisation using the *rmr_set_stimeout()* function
-allowing the user application to completely disable retires
-(set to 0), or to increase the number of retry loops.
-
-Transport Level Blocking
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The underlying transport mechanism used to send messages is
-configured in *non-blocking* mode. This means that if a
-message cannot be sent immediately the transport mechanism
-will **not** pause with the assumption that the inability to
-send will clear quickly (within a few milliseconds). This
-means that when the retry loop is completely disabled (set to
-0), that the failure to accept a message for sending by the
-underlying mechanisms (software or hardware) will be reported
-immediately to the user application.
-
-It should be noted that depending on the underlying transport
-mechanism being used, it is extremely likely that retry
-conditions will happen during normal operations. These are
-completely out of RMR's control, and there is nothing that
-RMR can do to avoid or mitigate these other than by allowing
-RMR to retry the send operation, and even then it is possible
-(e.g., during connection reattempts), that a single retry
-loop is not enough to guarantee a successful send.
-
-PAYLOAD SIZE
---------------------------------------------------------------------------------------------
-
-When crafting a response based on a received message, the
-user application must take care not to write more bytes to
-the message payload than the allocated message has. In the
-case of a received message, it is possible that the response
-needs to be larger than the payload associated with the
-inbound message. In order to use the return to sender
-function, the source information in the original message must
-be present in the response; information which cannot be added
-to a message buffer allocated through the standard RMR
-allocation function. To allocate a buffer with a larger
-payload, and which retains the necessary sender data needed
-by this function, the *rmr_realloc_payload()* function must
-be used to extend the payload to a size suitable for the
-response.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, a new message buffer, with an empty payload, is
-returned for the application to use for the next send. The
-state in this buffer will reflect the overall send operation
-state and should be RMR_OK.
-
-If the state in the returned buffer is anything other than
-RMR_OK, the user application may need to attempt a
-retransmission of the message, or take other action depending
-on the setting of errno as described below.
-
-In the event of extreme failure, a nil pointer is returned.
-In this case the value of errno might be of some use, for
-documentation, but there will be little that the user
-application can do other than to move on.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-The following values may be passed back in the *state* field
-of the returned message buffer.
-
-
-
-RMR_ERR_BADARG
-
- The message buffer pointer did not refer to a valid
- message.
-
-RMR_ERR_NOHDR
-
- The header in the message buffer was not valid or
- corrupted.
-
-RMR_ERR_NOENDPT
-
- The message type in the message buffer did not map to a
- known endpoint.
-
-RMR_ERR_SENDFAILED
-
- The send failed; errno has the possible reason.
-
-
-The following values may be assigned to errno on failure.
-
-
-INVAL
-
- Parameter(s) passed to the function were not valid, or the
- underlying message processing environment was unable to
- interpret the message.
-
-
-ENOKEY
-
- The header information in the message buffer was invalid.
-
-
-ENXIO
-
- No known endpoint for the message could be found.
-
-
-EMSGSIZE
-
- The underlying transport refused to accept the message
- because of a size value issue (message was not attempted
- to be sent).
-
-
-EFAULT
-
- The message referenced by the message buffer is corrupt
- (nil pointer or bad internal length).
-
-
-EBADF
-
- Internal RMR error; information provided to the message
- transport environment was not valid.
-
-
-ENOTSUP
-
- Sending was not supported by the underlying message
- transport.
-
-
-EFSM
-
- The device is not in a state that can accept the message.
-
-
-EAGAIN
-
- The device is not able to accept a message for sending.
- The user application should attempt to resend.
-
-
-EINTR
-
- The operation was interrupted by delivery of a signal
- before the message was sent.
-
-
-ETIMEDOUT
-
- The underlying message environment timed out during the
- send process.
-
-
-ETERM
-
- The underlying message environment is in a shutdown state.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3), rmr_init(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_rcv_msg(3),
-rmr_rcv_specific(3), rmr_ready(3), rmr_fib(3),
-rmr_has_str(3), rmr_set_stimeout(3), rmr_tokenise(3),
-rmr_mk_ring(3), rmr_ring_free(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_send_msg
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- rmr_mbuf_t* rmr_send_msg( void* vctx, rmr_mbuf_t* msg );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_send_msg function accepts a message buffer from the
-user application and attempts to send it. The destination of
-the message is selected based on the message type specified
-in the message buffer, and the matching information in the
-routing tables which are currently in use by the RMR library.
-This may actually result in the sending of the message to
-multiple destinations which could degrade expected overall
-performance of the user application. (Limiting excessive
-sending of messages is the responsibility of the
-application(s) responsible for building the routing table
-used by the RMR library, and not the responsibility of the
-library.)
-
-Retries
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The send operations in RMR will retry *soft* send failures
-until one of three conditions occurs:
-
-
-
-1.
-
- The message is sent without error
-
-
-2.
-
- The underlying transport reports a *hard* failure
-
-
-3.
-
- The maximum number of retry loops has been attempted
-
-
-A retry loop consists of approximately 1000 send attempts
-**without** any intervening calls to *sleep()* or *usleep().*
-The number of retry loops defaults to 1, thus a maximum of
-1000 send attempts is performed before returning to the user
-application. This value can be set at any point after RMr
-initialisation using the *rmr_set_stimeout()* function
-allowing the user application to completely disable retires
-(set to 0), or to increase the number of retry loops.
-
-Transport Level Blocking
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The underlying transport mechanism used to send messages is
-configured in *non-blocking* mode. This means that if a
-message cannot be sent immediately the transport mechanism
-will **not** pause with the assumption that the inability to
-send will clear quickly (within a few milliseconds). This
-means that when the retry loop is completely disabled (set to
-0), that the failure to accept a message for sending by the
-underlying mechanisms (software or hardware) will be reported
-immediately to the user application.
-
-It should be noted that depending on the underlying transport
-mechanism being used, it is extremely likely that retry
-conditions will happen during normal operations. These are
-completely out of RMR's control, and there is nothing that
-RMR can do to avoid or mitigate these other than by allowing
-RMR to retry the send operation, and even then it is possible
-(e.g., during connection reattempts), that a single retry
-loop is not enough to guarantee a successful send.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, a new message buffer, with an empty payload, is
-returned for the application to use for the next send. The
-state in this buffer will reflect the overall send operation
-state and will be RMR_OK when the send was successful.
-
-When the message cannot be successfully sent this function
-will return the unsent (original) message buffer with the
-state set to indicate the reason for failure. The value of
-*errno* may also be set to reflect a more detailed failure
-reason if it is known.
-
-In the event of extreme failure, a nil pointer is returned.
-In this case the value of errno might be of some use, for
-documentation, but there will be little that the user
-application can do other than to move on.
-
-**CAUTION:** In some cases it is extremely likely that the
-message returned by the send function does **not** reference
-the same memory structure. Thus is important for the user
-programme to capture the new pointer for future use or to be
-passed to rmr_free(). If you are experiencing either double
-free errors or segment faults in either rmr_free() or
-rmr_send_msg(), ensure that the return value from this
-function is being captured and used.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-The following values may be passed back in the *state* field
-of the returned message buffer.
-
-
-
-RMR_RETRY
-
- The message could not be sent, but the underlying
- transport mechanism indicates that the failure is
- temporary. If the send operation is tried again it might
- be successful.
-
-RMR_SEND_FAILED
-
- The send operation was not successful and the underlying
- transport mechanism indicates a permanent (hard) failure;
- retrying the send is not possible.
-
-RMR_ERR_BADARG
-
- The message buffer pointer did not refer to a valid
- message.
-
-RMR_ERR_NOHDR
-
- The header in the message buffer was not valid or
- corrupted.
-
-RMR_ERR_NOENDPT
-
- The message type in the message buffer did not map to a
- known endpoint.
-
-
-The following values may be assigned to errno on failure.
-
-
-INVAL
-
- Parameter(s) passed to the function were not valid, or the
- underlying message processing environment was unable to
- interpret the message.
-
-
-ENOKEY
-
- The header information in the message buffer was invalid.
-
-
-ENXIO
-
- No known endpoint for the message could be found.
-
-
-EMSGSIZE
-
- The underlying transport refused to accept the message
- because of a size value issue (message was not attempted
- to be sent).
-
-
-EFAULT
-
- The message referenced by the message buffer is corrupt
- (nil pointer or bad internal length).
-
-
-EBADF
-
- Internal RMR error; information provided to the message
- transport environment was not valid.
-
-
-ENOTSUP
-
- Sending was not supported by the underlying message
- transport.
-
-
-EFSM
-
- The device is not in a state that can accept the message.
-
-
-EAGAIN
-
- The device is not able to accept a message for sending.
- The user application should attempt to resend.
-
-
-EINTR
-
- The operation was interrupted by delivery of a signal
- before the message was sent.
-
-
-ETIMEDOUT
-
- The underlying message environment timed out during the
- send process.
-
-
-ETERM
-
- The underlying message environment is in a shutdown state.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-The following is a simple example of how the rmr_send_msg
-function is called. In this example, the send message buffer
-is saved between calls and reused eliminating alloc/free
-cycles.
-
-
-::
-
- static rmr_mbuf_t* send_msg = NULL; // message to send; reused on each call
- msg_t* send_pm; // payload for send
- msg_t* pm; // our message format in the received payload
- if( send_msg == NULL ) {
- send_msg = rmr_alloc_msg( mr, MAX_SIZE ); // new buffer to send
- }
- // reference payload and fill in message type
- pm = (msg_t*) send_msg->payload;
- send_msg->mtype = MT_ANSWER;
- msg->len = generate_data( pm ); // something that fills the payload in
- msg = rmr_send_msg( mr, send_msg ); // ensure new pointer used after send
- if( ! msg ) {
- return ERROR;
- } else {
- if( msg->state != RMR_OK ) {
- // check for RMR_ERR_RETRY, and resend if needed
- // else return error
- }
- }
- return OK;
-
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3), rmr_init(3),
-rmr_payload_size(3), rmr_rcv_msg(3), rmr_rcv_specific(3),
-rmr_rts_msg(3), rmr_ready(3), rmr_mk_ring(3),
-rmr_ring_free(3), rmr_torcv_rcv(3), rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_set_fack
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- void rmr_set_fack( void* vctx );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_set_fack function enables *fast TCP acknowledgements*
-if the underlying transport library supports it. This might
-be useful for applications which must send messages at a
-maximum rate.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-There is no return value.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-This function does not generate any errors.
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_init(3),
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_set_stimeout
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- rmr_mbuf_t* rmr_set_stimeout( void* vctx, int rloops );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_set_stimeout function sets the configuration for how
-RMr will retry message send operations which complete with
-either a *timeout* or *again* completion value. (Send
-operations include all of the possible message send
-functions: *rmr_send_msg(), rmr_call(), rmr_rts_msg()* and
-*rmr_wh_send_msg().* The *rloops* parameter sets the maximum
-number of retry loops that will be attempted before giving up
-and returning the unsuccessful state to the user application.
-Each retry loop is approximately 1000 attempts, and RMr does
-**not** invoke any sleep function between retries in the
-loop; a small, 1 mu-sec, sleep is executed between loop sets
-if the *rloops* value is greater than 1.
-
-
-Disabling Retries
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-By default, the send operations will execute with an *rloop*
-setting of 1; each send operation will attempt to resend the
-message approximately 1000 times before giving up. If the
-user application does not want to have send operations retry
-when the underlying transport mechanism indicates *timeout*
-or *again,* the application should invoke this function and
-pass a value of 0 (zero) for *rloops.* With this setting, all
-RMr send operations will attempt a send operation only
-**once,** returning immediately to the caller with the state
-of that single attempt.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-This function returns a -1 to indicate that the *rloops*
-value could not be set, and the value *RMR_OK* to indicate
-success.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-Currently errno is **not** set by this function; the only
-cause of a failure is an invalid context (*vctx*) pointer.
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-The following is a simple example of how the rmr_set_stimeout
-function is called.
-
-
-::
-
- #define NO_FLAGS 0
- char* port = "43086"; // port for message router listen
- int max_size = 4096; // max message size for default allocations
- void* mr_context; // message router context
- mr_context = rmr_init( port, max_size, NO_FLAGS );
- if( mr_context != NULL ) {
- rmr_set_stimeout( mr_context, 0 ); // turn off retries
- }
-
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3), rmr_init(3),
-rmr_payload_size(3), rmr_rcv_msg(3), rmr_rcv_specific(3),
-rmr_rts_msg(3), rmr_ready(3), rmr_mk_ring(3),
-rmr_ring_free(3), rmr_send_msg(3), rmr_torcv_rcv(3),
-rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_set_trace
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- int rmr_set_trace( rmr_mbuf_t* mbuf, unsigned char* data, int len )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_set_trace function will copy len bytes from data into
-the trace portion of mbuf. If the trace area of mbuf is not
-the correct size, the message buffer will be reallocated to
-ensure that enough space is available for the trace data.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The rmr_set_trace function returns the number of bytes
-successfully copied to the message. If 0 is returned either
-the message pointer was nil, or the size in the parameters
-was <= 0.
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_tralloc_msg(3), rmr_bytes2xact(3),
-rmr_bytes2payload(3), rmr_call(3), rmr_free_msg(3),
-rmr_get_rcvfd(3), rmr_get_meid(3), rmr_get_trace(3),
-rmr_get_trlen(3), rmr_init(3), rmr_init_trace(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_rcv_msg(3),
-rmr_rcv_specific(3), rmr_rts_msg(3), rmr_ready(3),
-rmr_fib(3), rmr_has_str(3), rmr_tokenise(3), rmr_mk_ring(3),
-rmr_ring_free(3), rmr_str2meid(3), rmr_str2xact(3),
-rmr_wh_open(3), rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_set_vlevel
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- #include <rmr/rmr_logging.h>
- void rmr_set_vlevel( int new_level )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_set_vlevel allows the user programme to set the
-verbosity level which is used to determine the messages RMR
-writes to standard error. The new_vlevel value must be one of
-the following constants which have the indicated meanings:
-
-
-RMR_VL_OFF
-
- Turns off all message writing. This includes the stats and
- debugging messages generated by the route collector thread
- which are normally affected only by the externally managed
- verbose level file (and related environment variable).
-
-
-RMR_VL_CRIT
-
- Write only messages of critical importance. From the point
- of view of RMR, when a critical proper behaviour of the
- library cannot be expected or guaranteed.
-
-RMR_VL_ERR
-
- Include error messages in the output. An error is an event
- from which RMR has no means to recover. Continued proper
- execution is likely except where the affected connection
- and/or component mentioned in the error is concerned.
-
-RMR_VL_WARN
-
- Include warning messages in the output. A warning
- indicates an event which is not considered to be normal,
- but is expected and continued acceptable behaviour of the
- system is assured.
-
-RMR_VL_INFO
-
- Include informational messagees in the output.
- Informational messages include some diagnostic information
- which explain the activities of RMR.
-
-RMR_VL_DEBUG
-
- Include all debugging messages in the output. Debugging
- must have also been enabled during the build as a
- precaution to accidentally enabling this level of output
- as it can grossly affect performance.
-
-
-Generally RMR does not write messages to the standard error
-device from *critical path* functions, therefore it is
-usually not harmful to enable a verbosity level of either
-RMR_VL_CRIT or RMR_VL_ERR.
-
-Messages written from the route table collection thread are
-still governed by the value placed into the verbose level
-control file (see the man page for rmr_init()); those
-messages are affected only when logging is completely
-disabled by passing RMR_VL_OFF to this function.
-
-The verbosity level can also be set via an environment
-variable prior to the start of the RMR based application. The
-environment variable is read only during initialisation; if
-the programme must change the value during execution, this
-function must be used. The default value, if this function is
-never called, and the environment variable is not present, is
-RMR_VL_ERR.
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_init(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_str2meid
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- int rmr_str2meid( rmr_mbuf_t* mbuf, unsigned char* src, int len )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_str2meid function will copy the string pointed to by
-src to the managed entity ID (meid) field in the given
-message. The field is a fixed length, gated by the constant
-RMR_MAX_MEID and if string length is larger than this value,
-then **nothing** will be copied. (Note, this differs slightly
-from the behaviour of the lrmr_bytes2meid() function.)
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, the value RMR_OK is returned. If the string
-cannot be copied to the message, the return value will be one
-of the errors listed below.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-If the return value is not RMR_OK, then it will be set to one
-of the values below.
-
-
-
-RMR_ERR_BADARG
-
- The message, or an internal portion of the message, was
- corrupted or the pointer was invalid.
-
-
-RMR_ERR_OVERFLOW
-
- The length passed in was larger than the maximum length of
- the field; only a portion of the source bytes were copied.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3),
-rmr_get_meid(3), rmr_get_rcvfd(3), rmr_payload_size(3),
-rmr_send_msg(3), rmr_rcv_msg(3), rmr_rcv_specific(3),
-rmr_rts_msg(3), rmr_ready(3), rmr_fib(3), rmr_has_str(3),
-rmr_tokenise(3), rmr_mk_ring(3), rmr_ring_free(3),
-rmr_bytes2meid(3), rmr_wh_open(3), rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_str2xact
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- int rmr_str2xact( rmr_mbuf_t* mbuf, unsigned char* src, int len )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_str2xact function will copy the string pointed to by
-src to the transaction ID (xaction) field in the given
-message. The field is a fixed length, gated by the constant
-RMR_MAX_XID and if string length is larger than this value,
-then **nothing** will be copied. (Note, this differs slightly
-from the behaviour of the lrmr_bytes2xact() function.)
-
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-On success, the value RMR_OK is returned. If the string
-cannot be copied to the message, the return value will be
-one of the errors listed below.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-If the return value is not RMR_OK, then it will be set to
-one of the values below.
-
-
-RMR_ERR_BADARG
-
- The message, or an internal portion of the message, was
- corrupted or the pointer was invalid.
-
-
-RMR_ERR_OVERFLOW
-
- The length passed in was larger than the maximum length of
- the field; only a portion of the source bytes were copied.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_bytes2meid(3), rmr_bytes2xact(3),
-rmr_call(3), rmr_free_msg(3), rmr_get_meid(3),
-rmr_get_rcvfd(3), rmr_get_xact(3), rmr_payload_size(3),
-rmr_send_msg(3), rmr_rcv_msg(3), rmr_rcv_specific(3),
-rmr_rts_msg(3), rmr_ready(3), rmr_fib(3), rmr_has_str(3),
-rmr_tokenise(3), rmr_mk_ring(3), rmr_ring_free(3),
-rmr_str2meid(3), rmr_wh_open(3), rmr_wh_send_msg(3)
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-RMR support functions
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- #include <rmr/ring_inline.h>
- char* rmr_fib( char* fname );
- int rmr_has_str( char const* buf, char const* str, char sep, int max );
- int rmr_tokenise( char* buf, char** tokens, int max, char sep );
- void* rmr_mk_ring( int size );
- void rmr_ring_free( void* vr );
- static inline void* rmr_ring_extract( void* vr )
- static inline int rmr_ring_insert( void* vr, void* new_data )
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-These functions support the RMR library, and are made
-available to user applications as some (e.g. route table
-generators) might need and/or want to make use of them. The
-rmr_fib function accepts a file name and reads the entire
-file into a single buffer. The intent is to provide an easy
-way to load a static route table without a lot of buffered
-I/O hoops.
-
-The rmr_has_str function accepts a *buffer* containing a set
-of delimited tokens (e.g. foo,bar,goo) and returns true if
-the target string, *str,* matches one of the tokens. The
-*sep* parameter provides the separation character in the
-buffer (e.g a comma) and *max* indicates the maximum number
-of tokens to split the buffer into before checking.
-
-The rmr_tokenise function is a simple tokeniser which splits
-*buf* into tokens at each occurrence of *sep*. Multiple
-occurrences of the separator character (e.g. a,,b) result in
-a nil token. Pointers to the tokens are placed into the
-*tokens* array provided by the caller which is assumed to
-have at least enough space for *max* entries.
-
-The rmr_mk_ring function creates a buffer ring with *size*
-entries.
-
-The rmr_ring_free function accepts a pointer to a ring
-context and frees the associated memory.
-
-The rmr_ring_insert and rmr_ring_extract functions are
-provided as static inline functions via the
-*rmr/ring_inline.h* header file. These functions both accept
-the ring *context* returned by mk_ring, and either insert a
-pointer at the next available slot (tail) or extract the data
-at the head.
-
-RETURN VALUES
---------------------------------------------------------------------------------------------
-
-The following are the return values for each of these
-functions.
-
-The rmr_fib function returns a pointer to the buffer
-containing the contents of the file. The buffer is terminated
-with a single nil character (0) making it a legitimate C
-string. If the file was empty or nonexistent, a buffer with
-an immediate nil character. If it is important to the calling
-programme to know if the file was empty or did not exist, the
-caller should use the system stat function call to make that
-determination.
-
-The rmr_has_str function returns 1 if *buf* contains the
-token referenced by &ita and false (0) if it does not. On
-error, a -1 value is returned and errno is set accordingly.
-
-The rmr_tokenise function returns the actual number of token
-pointers placed into *tokens*
-
-The rmr_mk_ring function returns a void pointer which is the
-*context* for the ring.
-
-The rmr_ring_insert function returns 1 if the data was
-successfully inserted into the ring, and 0 if the ring is
-full and the pointer could not be deposited.
-
-The rmr_ring_extract will return the data which is at the
-head of the ring, or NULL if the ring is empty.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-Not many of these functions set the value in errno, however
-the value may be one of the following:
-
-
-INVAL
-
- Parameter(s) passed to the function were not valid.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------
-
-rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3), rmr_init(3),
-rmr_payload_size(3), rmr_send_msg(3), rmr_rcv_msg(3),
-rmr_rcv_specific(3), rmr_rts_msg(3), rmr_ready(3),
-
-
-NAME
---------------------------------------------------------------------------------------------
-
-rmr_torcv_msg
-
-SYNOPSIS
---------------------------------------------------------------------------------------------
-
-
-::
-
- #include <rmr/rmr.h>
- rmr_mbuf_t* rmr_torcv_msg( void* vctx, rmr_mbuf_t* old_msg, int ms_to );
-
-
-
-DESCRIPTION
---------------------------------------------------------------------------------------------
-
-The rmr_torcv_msg function will pause for *ms_to*
-milliseconds waiting for a message to arrive. If a message
-arrives before the timeout expires the message buffer
-returned will have a status of RMR_OK and the payload will
-contain the data received. If the timeout expires before the
-message is received, the status will have the value
-RMR_ERR_TIMEOUT. When a received message is returned the
-message buffer will also contain the message type and length
-set by the sender. If messages were queued while waiting for
-the response to a previous invocation of rmr_call, the oldest
-message is removed from the queue and returned without delay.
-
-The *vctx* pointer is the pointer returned by the rmr_init
-function. *Old_msg* is a pointer to a previously used message
-buffer or NULL. The ability to reuse message buffers helps to
-avoid alloc/free cycles in the user application. When no
-buffer is available to supply, the receive function will
-allocate one.
-
-RETURN VALUE
---------------------------------------------------------------------------------------------
-
-The function returns a pointer to the rmr_mbuf_t structure
-which references the message information (state, length,
-payload), or a nil pointer in the case of an extreme error.
-
-ERRORS
---------------------------------------------------------------------------------------------
-
-The *state* field in the message buffer will be one of the
-following:
-
-
-
-RMR_OK
-
- The message buffer (payload) references the received data.
-
-
-RMR_ERR_INITFAILED
-
- The first call to this function must initialise an
- underlying system notification mechanism. On failure, this
- error is returned and errno will have the system error
- status set. If this function fails to intialise, the poll
- mechansim, it is likely that message receives will never
- be successful.
-
-
-RMR_ERR_TIMEOUT
-
- The timeout expired before a complete message was
- received. All other fields in the message buffer are not
- valid.
-
-
-RMR_ERR_EMPTY
-
- A message was received, but it had no payload. All other
- fields in the message buffer are not valid.
-
-
-
-
-INVAL
-
- Parameter(s) passed to the function were not valid.
-
-
-EBADF
-
- The underlying message transport is unable to process the
- request.
-
-
-ENOTSUP
-
- The underlying message transport is unable to process the
- request.
-
-
-EFSM
-
- The underlying message transport is unable to process the
- request.
-
-
-EAGAIN
-
- The underlying message transport is unable to process the
- request.
-
-
-EINTR
-
- The underlying message transport is unable to process the
- request.
-
-
-ETIMEDOUT
-
- The underlying message transport is unable to process the
- request.
-
-
-ETERM
-
- The underlying message transport is unable to process the
- request.
-
-
-EXAMPLE
---------------------------------------------------------------------------------------------
-
-
-SEE ALSO
---------------------------------------------------------------------------------------------