diff options
Diffstat (limited to 'extras/libmemif/docs/gettingstarted_doc.md')
| -rw-r--r-- | extras/libmemif/docs/gettingstarted_doc.md | 223 |
1 files changed, 0 insertions, 223 deletions
diff --git a/extras/libmemif/docs/gettingstarted_doc.md b/extras/libmemif/docs/gettingstarted_doc.md deleted file mode 100644 index abf9a1a06fd..00000000000 --- a/extras/libmemif/docs/gettingstarted_doc.md +++ /dev/null @@ -1,223 +0,0 @@ -## Getting started {#libmemif_gettingstarted_doc} - -#### Concept (Connecting to VPP) - -For detailed information on api calls and structures please refer to @ref libmemif.h. - -1. Initialize memif - - Declare callback function handling file descriptor event polling. -```C -int -control_fd_update (int fd, uint8_t events) -{ -... -} -``` - - Call memif initialization function. memif\_init -```C -err = memif_init (control_fd_update, APP_NAME, NULL, NULL); -``` - -> If event occurs on any file descriptor returned by this callback, call memif\_control\_fd\_handler function. Since version 2.0, last two optional arguments are used to specify custom memory allocation. -```C -memif_err = memif_control_fd_handler (evt.data.fd, events); -``` -> If callback function parameter for memif\_init function is set to NULL, libmemif will handle file descriptor event polling. - Api call memif\_poll\_event will call epoll\_pwait with user defined timeout to poll event on file descriptors opened by libmemif. -```C -/* main loop */ - while (1) - { - if (memif_poll_event (-1) < 0) - { - DBG ("poll_event error!"); - } - } -``` - -> Memif initialization function will initialize internal structures and create timer file descriptor, which will be used for sending periodic connection requests. Timer is disarmed if no memif interface is created. - -2. Creating interface - - Declare memif connection handle. -```C -memif_conn_handle_t c; -``` -> example app uses struct that contains connection handle, rx/tx buffers and other connection specific information. - - - Specify connection arguments. -```C -memif_conn_args_t args; -memset (&args, 0, sizeof (args)); -args.is_master = is_master; -args.log2_ring_size = 10; -args.buffer_size = 2048; -args.num_s2m_rings = 2; -args.num_m2s_rings = 2; -strncpy ((char *) args.interface_name, IF_NAME, strlen (IF_NAME)); -args.mode = 0; -args.interface_id = 0; -``` - - Declare callback functions called on connected/disconnected/interrupted status changed. -```C -int -on_connect (memif_conn_handle_t conn, void *private_ctx) -{ -... -} - -int -on_disconnect (memif_conn_handle_t conn, void *private_ctx) -{ - INFO ("memif connected!"); - return 0; -} -``` - - Call memif interface create function. memif\_create -```C -err = memif_create (&c->conn, - &args, on_connect, on_disconnect, on_interrupt, &ctx[index]); -``` -> If connection is in slave mode, arms timer file descriptor. -> If on interrupt callback is set to NULL, user will not be notified about interrupt. Use memif\_get\_queue\_efd call to get interrupt file descriptor for specific queue. -```C -int fd = -1; -err = memif_get_queue_efd (c->conn, data->qid, &fd); -``` - -3. Connection establishment - - User application will poll events on all file descriptors returned in memif\_control\_fd\_update\_t callback. - - On event call memif\_control\_fd\_handler. - - Everything else regarding connection establishment will be done internally. - - Once connection has been established, a callback will inform the user about connection status change. - -4. Interrupt packet receive - - If event is polled on interrupt file descriptor, libmemif will call memif\_interrupt\_t callback specified for every connection instance. -```C -int -on_interrupt (memif_conn_handle_t conn, void *private_ctx, uint16_t qid) -{ -... -} -``` - -6. Memif buffers - - Packet data are stored in memif\_buffer\_t. Pointer _data_ points to shared memory buffer, and unsigned integer *_len* contains buffer length. - - flags: MEMIF\_BUFFER\_FLAG\_NEXT states that the buffer is not large enough to contain whole packet, so next buffer contains the rest of the packet. (chained buffers) -```C -typedef struct -{ - uint16_t desc_index; - uint32_t len; - uint8_t flags; - void *data; -} memif_buffer_t; -``` - -5. Packet receive - - Api call memif\_rx\_burst will set all required fields in memif buffers provided by user application, dequeue received buffers and consume interrupt event on receive queue. The event is not consumed, if memif_rx_burst fails. -```C -err = memif_rx_burst (c->conn, qid, c->bufs, MAX_MEMIF_BUFS, &rx); -``` - - User application can then process packets. - - Api call memif\_refill\_queue will enqueue rx buffers. -```C -err = memif_refill_queue (c->conn, qid, rx); -``` - -6. Packet transmit - - Api call memif\_buffer\_alloc will find free tx buffers and set all required fields in memif buffers provided by user application. -```C -err = memif_buffer_alloc (c->conn, qid, c->tx_bufs, n, &r); -``` - - User application can populate shared memory buffers with packets. - - Api call memif\_tx\_burst will enqueue tx buffers -```C -err = memif_tx_burst (c->conn, qid, c->tx_bufs, c->tx_buf_num, &r); -``` - -7. Helper functions - - Memif version -```C -uint16_t memif_ver = memif_get_version (); -``` - - Memif details - - Api call memif\_get\_details will return details about connection. -```C -err = memif_get_details (c->conn, &md, buf, buflen); -``` - - Memif error messages - - Every api call returns error code (integer value) mapped to error string. - - Call memif\_strerror will return error message assigned to specific error code. -```C -if (err != MEMIF_ERR_SUCCESS) - INFO ("memif_get_details: %s", memif_strerror (err)); -``` - - Not all syscall errors are translated to memif error codes. If error code 1 (MEMIF\_ERR\_SYSCALL) is returned then libmemif needs to be compiled with -DMEMIF_DBG flag to print error message. Use _make -B_ to rebuild libmemif in debug mode. - -#### Example app (libmemif fd event polling): - -- @ref extras/libmemif/examples/icmp_responder - -> Optional argument: transmit queue id. -``` -icmpr 1 -``` -> Set transmit queue id to 1. Default is 0. -> Application will create memif interface in slave mode and try to connect to VPP. Exit using Ctrl+C. Application will handle SIGINT signal, free allocated memory and exit with EXIT_SUCCESS. - -#### Example app: - -ICMP Responder custom fd event polling. - -- @ref extras/libmemif/examples/icmp_responder-epoll - -#### Example app (multi-thread queue polling) - -ICMP Responder multi-thread. -- @ref extras/libmemif/examples/icmp_responder-mt - -> Simple example of libmemif multi-thread usage. Connection establishment is handled by main thread. There are two rx/tx queues in this example. One in polling mode and second in interrupt mode. - -VPP config: -``` -# create interface memif id 0 master -# set int state memif0 up -# set int ip address memif0 192.168.1.1/24 -# ping 192.168.1.2 -``` -For multiple rings (queues) support run VPP with worker threads: -example startup.conf: -``` -unix { - interactive - nodaemon - full-coredump -} - -cpu { - workers 2 -} -``` -VPP config: -``` -# create interface memif id 0 master -# set int state memif0 up -# set int ip address memif0 192.168.1.1/24 -# ping 192.168.1.2 -``` -> Master mode queue number is limited by worker threads. Slave mode interface needs to specify number of queues. -``` -# create memif id 0 slave rx-queues 2 tx-queues 2 -``` -> Example applications use VPP default socket file for memif: /run/vpp/memif.sock -> For master mode, socket directory must exist prior to memif\_create call. - -#### Unit tests - -Unit tests use [Check](https://libcheck.github.io/check/index.html) framework. This framework must be installed in order to build *unit\_test* binary. -Ubuntu/Debian: -``` -sudo apt-get install check -``` -[More platforms](https://libcheck.github.io/check/web/install.html) - |