libmemif: refactor connection establishment

per_thread_ namespace fuctionality replaced by memif socket.
Interfaces are grouped by memif socket which holds interface database.
Each thread can create it's unique memif socket. The path name
can be equal across threads so that the app only uses one
UNIX socket. In case of listener socket, listener fd
can be obtained and set using APIs.

This change allows:
  - No lookup on file descriptor events
    - improves interrupt handling
  - Loopback support (connect two interfaces in one app)
    - usefull for debugging and testing
  - Improves code readability by providing control channel
    abstraction for each interface and listener sockets

Type: refactor

Signed-off-by: Jakub Grajciar <jgrajcia@cisco.com>
Change-Id: I1b8261042431c0376646ab4c4c831f6e59dd3eed

1 files changed, 68 insertions, 66 deletions

diff --git a/extras/libmemif/src/memif_private.h b/extras/libmemif/src/memif_private.h
index 9542936983e..71a4bc879f4 100644
--- a/extras/libmemif/src/memif_private.h
+++ b/extras/libmemif/src/memif_private.h
@@ -27,6 +27,7 @@
 #include <limits.h>
 #include <sys/timerfd.h>
 #include <string.h>
+#include <sys/queue.h>
 
 #include <memif.h>
 #include <libmemif.h>
@@ -103,7 +104,7 @@ typedef enum
 typedef struct
 {
   void *addr;
-  uint32_t region_size;
+  memif_region_size_t region_size;
   uint32_t buffer_offset;
   int fd;
   uint8_t is_external;
@@ -125,20 +126,10 @@ typedef struct
   uint32_t next_buf; /* points to next free buffer */
 } memif_queue_t;
 
-typedef struct memif_msg_queue_elt
-{
-  memif_msg_t msg;
-  int fd;
-  struct memif_msg_queue_elt *next;
-} memif_msg_queue_elt_t;
-
 struct memif_connection;
 
 typedef struct memif_connection memif_connection_t;
 
-/* functions called by memif_control_fd_handler */
-typedef int (memif_fn) (memif_connection_t * conn);
-
 typedef struct
 {
   uint8_t num_s2m_rings;
@@ -147,7 +138,7 @@ typedef struct
   memif_log2_ring_size_t log2_ring_size;
 } memif_conn_run_args_t;
 
-struct libmemif_main;
+struct memif_control_channel;
 
 typedef struct memif_connection
 {
@@ -155,17 +146,12 @@ typedef struct memif_connection
   memif_conn_args_t args;
   memif_conn_run_args_t run_args;
 
-  int fd;
-
-  memif_fn *write_fn, *read_fn, *error_fn;
+  struct memif_control_channel *control_channel;
 
   memif_connection_update_t *on_connect, *on_disconnect;
-  memif_interrupt_t *on_interrupt;
+  memif_on_interrupt_t *on_interrupt;
   void *private_ctx;
 
-  /* connection message queue */
-  memif_msg_queue_elt_t *msg_queue;
-
   uint8_t remote_if_name[MEMIF_NAME_LEN];
   uint8_t remote_name[MEMIF_NAME_LEN];
   uint8_t remote_disconnect_string[96];
@@ -180,61 +166,85 @@ typedef struct memif_connection
 
   uint16_t flags;
 #define MEMIF_CONNECTION_FLAG_WRITE (1 << 0)
+
+  TAILQ_ENTRY (memif_connection) next;
 } memif_connection_t;
 
-typedef struct
+/** \brief Memif message queue element
+ * @param msg - memif control message (defined in memif.h)
+ * @param nex - tailq entry
+ * @param fd - File descriptor to be shared with peer endpoint
+ */
+typedef struct memif_msg_queue_elt
 {
-  int key;
-  void *data_struct;
-} memif_list_elt_t;
+  memif_msg_t msg;
+  TAILQ_ENTRY (memif_msg_queue_elt) next;
+  int fd;
+} memif_msg_queue_elt_t;
 
-typedef struct
+struct memif_socket;
+
+/** \brief Memif control channel
+ * @param fd - fd used for communbication
+ * @param msg_queue - message queue
+ * @param conn - memif connection using this control channel
+ * @param sock - socket this control channel belongs to
+ *
+ * Memif controll channel represents one end of communication between two memif
+ * endpoints. The controll channel is responsible for receiving and
+ * transmitting memif control messages via UNIX domain socket.
+ */
+typedef struct memif_control_channel
 {
   int fd;
-  uint16_t use_count;
-  memif_socket_type_t type;
-  uint8_t filename[108];
-  /* unique database */
-  struct libmemif_main *lm;
-  uint16_t interface_list_len;
-  void *private_ctx;
-  memif_list_elt_t *interface_list;	/* memif master interfaces listening on this socket */
-} memif_socket_t;
-
-typedef struct libmemif_main
+  TAILQ_HEAD (, memif_msg_queue_elt) msg_queue;
+  memif_connection_t *conn;
+  struct memif_socket *sock;
+} memif_control_channel_t;
+
+/** \brief Memif socket
+ * @param args - memif socket arguments (from libmemif.h)
+ * @param epfd - epoll fd, used for internal fd polling
+ * @param poll_cancel_fd - if event is received on this fd, interrupt polling
+ * @param listener_fd - listener fd if this socket is listener else -1
+ * @param private_ctx - private context
+ * @param master_interfaces - master interface queue
+ * @param slave_interfaces - slave interface queue
+ * @param control_channels - controll channel queue
+ */
+typedef struct memif_socket
 {
-  memif_control_fd_update_t *control_fd_update;
-  int timerfd;
+  memif_socket_args_t args;
   int epfd;
   int poll_cancel_fd;
-  struct itimerspec arm, disarm;
-  uint16_t disconn_slaves;
-  uint8_t app_name[MEMIF_NAME_LEN];
-
+  int listener_fd;
+  int timer_fd;
+  struct itimerspec timer;
   void *private_ctx;
+  TAILQ_HEAD (, memif_connection) master_interfaces;
+  TAILQ_HEAD (, memif_connection) slave_interfaces;
 
-  memif_socket_handle_t default_socket;
-
+  /* External region callbacks */
   memif_add_external_region_t *add_external_region;
   memif_get_external_region_addr_t *get_external_region_addr;
   memif_del_external_region_t *del_external_region;
   memif_get_external_buffer_offset_t *get_external_buffer_offset;
+} memif_socket_t;
 
-  memif_alloc_t *alloc;
-  memif_realloc_t *realloc;
-  memif_free_t *free;
+typedef int (memif_fd_event_handler_t) (memif_fd_event_type_t type,
+					void *private_ctx);
 
-  uint16_t control_list_len;
-  uint16_t interrupt_list_len;
-  uint16_t socket_list_len;
-  uint16_t pending_list_len;
-  memif_list_elt_t *control_list;
-  memif_list_elt_t *interrupt_list;
-  memif_list_elt_t *socket_list;
-  memif_list_elt_t *pending_list;
-} libmemif_main_t;
+typedef struct memif_fd_event_data
+{
+  memif_fd_event_handler_t *event_handler;
+  void *private_ctx;
+} memif_fd_event_data_t;
 
-extern libmemif_main_t libmemif_main;
+typedef struct memif_interrupt
+{
+  memif_connection_t *c;
+  uint16_t qid;
+} memif_interrupt_t;
 
 /* main.c */
 
@@ -246,19 +256,11 @@ int memif_init_regions_and_queues (memif_connection_t * c);
 
 int memif_disconnect_internal (memif_connection_t * c);
 
+int memif_interrupt_handler (memif_fd_event_type_t type, void *private_ctx);
+
 /* map errno to memif error code */
 int memif_syscall_error_handler (int err_code);
 
-int add_list_elt (libmemif_main_t *lm, memif_list_elt_t * e, memif_list_elt_t ** list,
-		  uint16_t * len);
-
-int get_list_elt (memif_list_elt_t ** e, memif_list_elt_t * list,
-		  uint16_t len, int key);
-
-int free_list_elt (memif_list_elt_t * list, uint16_t len, int key);
-
-libmemif_main_t *get_libmemif_main (memif_socket_t * ms);
-
 #ifndef __NR_memfd_create
 #if defined __x86_64__
 #define __NR_memfd_create 319