Update README.md

Author: JakubGrajciar

README.md

@@ -11,8 +11,8 @@ Shared memory packet interface (memif) provides high performance packet transmit
   - [x] ICMP responder example app
 - [x] Transmit/receive packets
 - [x] Interrupt mode support
-- [ ] File descriptor event polling in libmemif (optional)
-  - [ ] Simplify file descriptor event polling (one handler for control and interrupt channel)
+- [x] File descriptor event polling in libmemif (optional)
+  - [x] Simplify file descriptor event polling (one handler for control and interrupt channel)
 - [ ] Multiple connections
 - [ ] Multiple regions
 - [ ] Multipe queues
@@ -72,6 +72,10 @@ For detailed information on api calls and structures please refer to [libmemif.h
 
 > If event occures on any file descriptor returned by this callback, call memif\_control\_fd\_handler function.
     
+WIP:
+  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 wit user defined timeout to poll event on file descriptors opend by libmemif.
+    
 > Mmeif 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
@@ -88,9 +92,7 @@ For detailed information on api calls and structures please refer to [libmemif.h
     - Once connection has been established, a callback will inform the user about connection status change.
 
 4. Interrupt packet receive
-   - Interrupt mode is still Work In Progress and will be simplified in furure patch.
-   - For interrupt mode, user application is required to register interrupt file descriptor for event polling. Api call memif\_get\_queue\_efd will return this interrupt file descriptor.
-     - If event occures on this file descriptor, there are packets in shared memory to be received.
+    - If event is polled on interrupt file descriptor, libmemif will call memif\_interrupt\_t callback specified for every connection instance.
 
 6. Memif buffers
     - Packet data are stored in memif\_buffer\_t. Pointer _data_ points to shared memory buffer, and unsigned integer *data\_len* contains packet data length.
@@ -118,10 +120,15 @@ For detailed information on api calls and structures please refer to [libmemif.h
 
 - [ICMP Responder](examples/icmp_responder/main.c)
 
+#### Example app (libmemif fd event polling):
+- [ICMP Responder](examples/icmp_responder2/main.c)
+> WIP! Application will create memif interface in slave mode and try to connect to VPP. Exit using Ctrl+C.
+
 VPP side config:
 ```
 # create memif id 0 master
 # set int state memif0 up
 # set int ip address memif0 192.168.1.1/24
 # ping 192.168.1.2
 ```
+> Example applications use VPP default socket file for memif: /run/vpp/memif.sock