Shared memory packet interface (memif) library

Change-Id: I5097462ae85acd705f19e92517c01094dba7565f
Signed-off-by: Jakub Grajciar <grajciar.jakub@gmail.com>

1 files changed, 1810 insertions, 0 deletions

diff --git a/extras/libmemif/src/main.c b/extras/libmemif/src/main.c
new file mode 100644
index 00000000000..d1b59eea8fe
--- /dev/null
+++ b/extras/libmemif/src/main.c
@@ -0,0 +1,1810 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+#include <stdint.h>
+#include <net/if.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/uio.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <inttypes.h>
+#include <string.h>
+#include <stdio.h>
+#include <netdb.h>
+#include <linux/ip.h>
+#include <linux/icmp.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <netinet/if_ether.h>
+#include <net/if_arp.h>
+#include <asm/byteorder.h>
+#include <byteswap.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/eventfd.h>
+#include <sys/timerfd.h>
+#include <sys/epoll.h>
+#include <signal.h>
+
+/* memif protocol msg, ring and descriptor definitions */
+#include <memif.h>
+/* memif api */
+#include <libmemif.h>
+/* socket messaging functions */
+#include <socket.h>
+/* private structs and functions */
+#include <memif_private.h>
+
+#define ERRLIST_LEN 36
+#define MAX_ERRBUF_LEN 256
+
+#if __x86_x64__
+#define MEMIF_MEMORY_BARRIER() __builtin_ia32_sfence ()
+#else
+#define MEMIF_MEORY_BARRIER() __sync_synchronize ()
+#endif /* __x86_x64__ */
+
+libmemif_main_t libmemif_main;
+int memif_epfd;
+
+static char memif_buf[MAX_ERRBUF_LEN];
+
+const char *memif_errlist[ERRLIST_LEN] = {	/* MEMIF_ERR_SUCCESS */
+  "Success.",
+  /* MEMIF_ERR_SYSCALL */
+  "Unspecified syscall error (build with -DMEMIF_DBG or make debug).",
+  /* MEMIF_ERR_ACCES */
+  "Permission to resoure denied.",
+  /* MEMIF_ERR_NO_FILE */
+  "Socket file does not exist",
+  /* MEMIF_ERR_FILE_LIMIT */
+  "System limit on total numer of open files reached.",
+  /* MEMIF_ERR_PROC_FILE_LIMIT */
+  "Per-process limit on total number of open files reached.",
+  /* MEMIF_ERR_ALREADY */
+  "Connection already requested.",
+  /* MEMIF_ERR_AGAIN */
+  "File descriptor refers to file other than socket, or operation would block.",
+  /* MEMIF_ERR_BAD_FD */
+  "Bad file descriptor.",
+  /* MEMIF_ERR_NOMEM */
+  "Out of memory.",
+  /* MEMIF_ERR_INVAL_ARG */
+  "Invalid argument.",
+  /* MEMIF_ERR_NOCONN */
+  "Memif connection handle does not point to existing conenction",
+  /* MEMIF_ERR_CONN */
+  "Memif connection handle points to existing connection",
+  /* MEMIF_ERR_CB_FDUPDATE */
+  "Callback memif_control_fd_update_t returned error",
+  /* MEMIF_ERR_FILE_NOT_SOCK */
+  "File specified by socket filename exists and is not socket.",
+  /* MEMIF_ERR_NO_SHMFD */
+  "Missing shared memory file descriptor. (internal error)",
+  /* MEMIF_ERR_COOKIE */
+  "Invalid cookie on ring. (internal error)",
+  /* MEMIF_ERR_NOBUF_RING */
+  "Ring buffer full.",
+  /* MEMIF_ERR_NOBUF */
+  "Not enough memif buffers. There are unreceived data in shared memory.",
+  /* MEMIF_ERR_NOBUF_DET */
+  "Not enough space for memif details in suplied buffer. String data might be malformed.",
+  /* MEMIF_ERR_INT_WRITE */
+  "Send interrupt error.",
+  /* MEMIF_ERR_MFMSG */
+  "Malformed message received on control channel.",
+  /* MEMIF_ERR_QID */
+  "Invalid queue id",
+  /* MEMIF_ERR_PROTO */
+  "Incompatible memory interface protocol version.",
+  /* MEMIF_ERR_ID */
+  "Unmatched interface id.",
+  /* MEMIF_ERR_ACCSLAVE */
+  "Slave cannot accept connection reqest.",
+  /* MEMIF_ERR_ALRCONN */
+  "Interface is already connected.",
+  /* MEMIF_ERR_MODE */
+  "Mode mismatch.",
+  /* MEMIF_ERR_SECRET */
+  "Secret mismatch.",
+  /* MEMIF_ERR_NOSECRET */
+  "Secret required.",
+  /* MEMIF_ERR_MAXREG */
+  "Limit on total number of regions reached.",
+  /* MEMIF_ERR_MAXRING */
+  "Limit on total number of ring reached.",
+  /* MEMIF_ERR_NO_INTFD */
+  "Missing interrupt file descriptor. (internal error)",
+  /* MEMIF_ERR_DISCONNECT */
+  "Interface received disconnect request.",
+  /* MEMIF_ERR_DISCONNECTED */
+  "Interface is disconnected.",
+  /* MEMIF_ERR_UNKNOWN_MSG */
+  "Unknown message type received on control channel. (internal error)"
+};
+
+#define MEMIF_ERR_UNDEFINED "undefined error"
+
+char *
+memif_strerror (int err_code)
+{
+  if (err_code >= ERRLIST_LEN)
+    {
+      strncpy (memif_buf, MEMIF_ERR_UNDEFINED, strlen (MEMIF_ERR_UNDEFINED));
+      memif_buf[strlen (MEMIF_ERR_UNDEFINED)] = '\0';
+    }
+  else
+    {
+      strncpy (memif_buf, memif_errlist[err_code],
+	       strlen (memif_errlist[err_code]));
+      memif_buf[strlen (memif_errlist[err_code])] = '\0';
+    }
+  return memif_buf;
+}
+
+#define DBG_TX_BUF (0)
+#define DBG_RX_BUF (1)
+
+#ifdef MEMIF_DBG_SHM
+static void
+print_bytes (void *data, uint16_t len, uint8_t q)
+{
+  if (q == DBG_TX_BUF)
+    printf ("\nTX:\n\t");
+  else
+    printf ("\nRX:\n\t");
+  int i;
+  for (i = 0; i < len; i++)
+    {
+      if (i % 8 == 0)
+	printf ("\n%d:\t", i);
+      printf ("%02X ", ((uint8_t *) (data))[i]);
+    }
+  printf ("\n\n");
+}
+#endif /* MEMIF_DBG */
+
+int
+memif_syscall_error_handler (int err_code)
+{
+  DBG_UNIX ("%s", strerror (err_code));
+
+  if (err_code == 0)
+    return MEMIF_ERR_SUCCESS;
+  if (err_code == EACCES)
+    return MEMIF_ERR_ACCES;
+  if (err_code == ENFILE)
+    return MEMIF_ERR_FILE_LIMIT;
+  if (err_code == EMFILE)
+    return MEMIF_ERR_PROC_FILE_LIMIT;
+  if (err_code == ENOMEM)
+    return MEMIF_ERR_NOMEM;
+/* connection refused if master dows not exist
+    this error would spam the user until master was created */
+  if (err_code == ECONNREFUSED)
+    return MEMIF_ERR_SUCCESS;
+  if (err_code == EALREADY)
+    return MEMIF_ERR_ALREADY;
+  if (err_code == EAGAIN)
+    return MEMIF_ERR_AGAIN;
+  if (err_code == EBADF)
+    return MEMIF_ERR_BAD_FD;
+  if (err_code == ENOENT)
+    return MEMIF_ERR_NO_FILE;
+
+  /* other syscall errors */
+  return MEMIF_ERR_SYSCALL;
+}
+
+static int
+memif_add_epoll_fd (int fd, uint32_t events)
+{
+  if (fd < 0)
+    {
+      DBG ("invalid fd %d", fd);
+      return -1;
+    }
+  struct epoll_event evt;
+  memset (&evt, 0, sizeof (evt));
+  evt.events = events;
+  evt.data.fd = fd;
+  if (epoll_ctl (memif_epfd, EPOLL_CTL_ADD, fd, &evt) < 0)
+    {
+      DBG ("epoll_ctl: %s fd %d", strerror (errno), fd);
+      return -1;
+    }
+  DBG ("fd %d added to epoll", fd);
+  return 0;
+}
+
+static int
+memif_mod_epoll_fd (int fd, uint32_t events)
+{
+  if (fd < 0)
+    {
+      DBG ("invalid fd %d", fd);
+      return -1;
+    }
+  struct epoll_event evt;
+  memset (&evt, 0, sizeof (evt));
+  evt.events = events;
+  evt.data.fd = fd;
+  if (epoll_ctl (memif_epfd, EPOLL_CTL_MOD, fd, &evt) < 0)
+    {
+      DBG ("epoll_ctl: %s fd %d", strerror (errno), fd);
+      return -1;
+    }
+  DBG ("fd %d moddified on epoll", fd);
+  return 0;
+}
+
+static int
+memif_del_epoll_fd (int fd)
+{
+  if (fd < 0)
+    {
+      DBG ("invalid fd %d", fd);
+      return -1;
+    }
+  struct epoll_event evt;
+  memset (&evt, 0, sizeof (evt));
+  if (epoll_ctl (memif_epfd, EPOLL_CTL_DEL, fd, &evt) < 0)
+    {
+      DBG ("epoll_ctl: %s fd %d", strerror (errno), fd);
+      return -1;
+    }
+  DBG ("fd %d removed from epoll", fd);
+  return 0;
+}
+
+int
+memif_control_fd_update (int fd, uint8_t events)
+{
+  if (events & MEMIF_FD_EVENT_DEL)
+    return memif_del_epoll_fd (fd);
+
+  uint32_t evt = 0;
+  if (events & MEMIF_FD_EVENT_READ)
+    evt |= EPOLLIN;
+  if (events & MEMIF_FD_EVENT_WRITE)
+    evt |= EPOLLOUT;
+
+  if (events & MEMIF_FD_EVENT_MOD)
+    return memif_mod_epoll_fd (fd, evt);
+
+  return memif_add_epoll_fd (fd, evt);
+}
+
+int
+add_list_elt (memif_list_elt_t * e, memif_list_elt_t ** list, uint16_t * len)
+{
+  libmemif_main_t *lm = &libmemif_main;
+
+  int i;
+  for (i = 0; i < *len; i++)
+    {
+      if ((*list)[i].data_struct == NULL)
+	{
+	  (*list)[i].key = e->key;
+	  (*list)[i].data_struct = e->data_struct;
+	  return i;
+	}
+    }
+  memif_list_elt_t *tmp;
+  tmp = realloc (*list, sizeof (memif_list_elt_t) * *len * 2);
+  if (tmp == NULL)
+    return -1;
+
+  for (i = *len; i < *len * 2; i++)
+    {
+      tmp[i].key = -1;
+      tmp[i].data_struct = NULL;
+    }
+
+  tmp[*len].key = e->key;
+  tmp[*len].data_struct = e->data_struct;
+  i = *len;
+  *len = *len * 2;
+  *list = tmp;
+
+  return i;
+}
+
+int
+get_list_elt (memif_list_elt_t ** e, memif_list_elt_t * list, uint16_t len,
+	      int key)
+{
+  if (key == -1)
+    {
+      *e = NULL;
+      return -1;
+    }
+  int i;
+  for (i = 0; i < len; i++)
+    {
+      if (list[i].key == key)
+	{
+	  *e = &list[i];
+	  return 0;
+	}
+    }
+  *e = NULL;
+  return -1;
+}
+
+/* does not free memory, only marks element as free */
+int
+free_list_elt (memif_list_elt_t * list, uint16_t len, int key)
+{
+  int i;
+  for (i = 0; i < len; i++)
+    {
+      if (list[i].key == key)
+	{
+	  list[i].key = -1;
+	  list[i].data_struct = NULL;
+	  return 0;
+	}
+    }
+
+  return -1;
+}
+
+int
+free_list_elt_ctx (memif_list_elt_t * list, uint16_t len,
+		   memif_connection_t * ctx)
+{
+  int i;
+  for (i = 0; i < len; i++)
+    {
+      if (list[i].key == -1)
+	{
+	  if (list[i].data_struct == ctx)
+	    {
+	      list[i].data_struct = NULL;
+	      return 0;
+	    }
+	}
+    }
+
+  return -1;
+}
+
+static void
+memif_control_fd_update_register (memif_control_fd_update_t * cb)
+{
+  libmemif_main_t *lm = &libmemif_main;
+  lm->control_fd_update = cb;
+}
+
+int
+memif_init (memif_control_fd_update_t * on_control_fd_update, char *app_name)
+{
+  int err = MEMIF_ERR_SUCCESS;	/* 0 */
+  libmemif_main_t *lm = &libmemif_main;
+
+  if (app_name)
+    {
+      lm->app_name = malloc (strlen (app_name) + sizeof (char));
+      memset (lm->app_name, 0, strlen (app_name) + sizeof (char));
+      strncpy ((char *) lm->app_name, app_name, strlen (app_name));
+    }
+  else
+    {
+      lm->app_name = malloc (strlen (MEMIF_DEFAULT_APP_NAME) + sizeof (char));
+      memset (lm->app_name, 0, strlen (app_name) + sizeof (char));
+      strncpy ((char *) lm->app_name, MEMIF_DEFAULT_APP_NAME,
+	       strlen (MEMIF_DEFAULT_APP_NAME));
+    }
+
+  /* register control fd update callback */
+  if (on_control_fd_update != NULL)
+    memif_control_fd_update_register (on_control_fd_update);
+  else
+    {
+      memif_epfd = epoll_create (1);
+      memif_control_fd_update_register (memif_control_fd_update);
+      DBG ("libmemif event polling initialized");
+    }
+
+  memset (&lm->ms, 0, sizeof (memif_socket_t));
+
+  lm->control_list_len = 2;
+  lm->interrupt_list_len = 2;
+  lm->listener_list_len = 1;
+  lm->pending_list_len = 1;
+
+  lm->control_list =
+    malloc (sizeof (memif_list_elt_t) * lm->control_list_len);
+  lm->interrupt_list =
+    malloc (sizeof (memif_list_elt_t) * lm->interrupt_list_len);
+  lm->listener_list =
+    malloc (sizeof (memif_list_elt_t) * lm->listener_list_len);
+  lm->pending_list =
+    malloc (sizeof (memif_list_elt_t) * lm->pending_list_len);
+
+  int i;
+  for (i = 0; i < lm->control_list_len; i++)
+    {
+      lm->control_list[i].key = -1;
+      lm->control_list[i].data_struct = NULL;
+    }
+  for (i = 0; i < lm->interrupt_list_len; i++)
+    {
+      lm->interrupt_list[i].key = -1;
+      lm->interrupt_list[i].data_struct = NULL;
+    }
+  for (i = 0; i < lm->listener_list_len; i++)
+    {
+      lm->listener_list[i].key = -1;
+      lm->listener_list[i].data_struct = NULL;
+    }
+  for (i = 0; i < lm->pending_list_len; i++)
+    {
+      lm->pending_list[i].key = -1;
+      lm->pending_list[i].data_struct = NULL;
+    }
+
+  lm->disconn_slaves = 0;
+
+  lm->timerfd = timerfd_create (CLOCK_REALTIME, TFD_NONBLOCK);
+  if (lm->timerfd < 0)
+    {
+      err = errno;
+      DBG ("timerfd: %s", strerror (err));
+      return memif_syscall_error_handler (err);
+    }
+
+  lm->arm.it_value.tv_sec = 2;
+  lm->arm.it_value.tv_nsec = 0;
+  lm->arm.it_interval.tv_sec = 2;
+  lm->arm.it_interval.tv_nsec = 0;
+  memset (&lm->disarm, 0, sizeof (lm->disarm));
+
+  if (lm->control_fd_update (lm->timerfd, MEMIF_FD_EVENT_READ) < 0)
+    {
+      DBG ("callback type memif_control_fd_update_t error!");
+      return MEMIF_ERR_CB_FDUPDATE;
+    }
+
+  return 0;
+}
+
+static inline memif_ring_t *
+memif_get_ring (memif_connection_t * conn, memif_ring_type_t type,
+		uint16_t ring_num)
+{
+  if (&conn->regions[0] == NULL)
+    return NULL;
+  void *p = conn->regions[0].shm;
+  int ring_size =
+    sizeof (memif_ring_t) +
+    sizeof (memif_desc_t) * (1 << conn->run_args.log2_ring_size);
+  p += (ring_num + type * conn->run_args.num_s2m_rings) * ring_size;
+
+  return (memif_ring_t *) p;
+}
+
+int
+memif_set_rx_mode (memif_conn_handle_t c, memif_rx_mode_t rx_mode,
+		   uint16_t qid)
+{
+  memif_connection_t *conn = (memif_connection_t *) c;
+  if (conn == NULL)
+    return MEMIF_ERR_NOCONN;
+  uint8_t num =
+    (conn->args.is_master) ? conn->run_args.num_s2m_rings : conn->run_args.
+    num_m2s_rings;
+  if (qid >= num)
+    return MEMIF_ERR_QID;
+
+  conn->rx_queues[qid].ring->flags = rx_mode;
+  DBG ("rx_mode flag: %u", conn->rx_queues[qid].ring->flags);
+  return MEMIF_ERR_SUCCESS;
+}
+
+int
+memif_create (memif_conn_handle_t * c, memif_conn_args_t * args,
+	      memif_connection_update_t * on_connect,
+	      memif_connection_update_t * on_disconnect,
+	      memif_interrupt_t * on_interrupt, void *private_ctx)
+{
+  int err, i, index, sockfd = -1;
+  memif_list_elt_t list_elt;
+  memif_connection_t *conn = (memif_connection_t *) * c;
+  if (conn != NULL)
+    {
+      DBG ("This handle already points to existing memif.");
+      return MEMIF_ERR_CONN;
+    }
+  conn = (memif_connection_t *) malloc (sizeof (memif_connection_t));
+  if (conn == NULL)
+    {
+      err = memif_syscall_error_handler (errno);
+      goto error;
+    }
+  memset (conn, 0, sizeof (memif_connection_t));
+
+  libmemif_main_t *lm = &libmemif_main;
+
+  conn->args.interface_id = args->interface_id;
+
+  if (args->log2_ring_size == 0)
+    args->log2_ring_size = MEMIF_DEFAULT_LOG2_RING_SIZE;
+  if (args->buffer_size == 0)
+    args->buffer_size = MEMIF_DEFAULT_BUFFER_SIZE;
+  if (args->num_s2m_rings == 0)
+    args->num_s2m_rings = MEMIF_DEFAULT_TX_QUEUES;
+  if (args->num_m2s_rings == 0)
+    args->num_m2s_rings = MEMIF_DEFAULT_RX_QUEUES;
+
+  conn->args.num_s2m_rings = args->num_s2m_rings;
+  conn->args.num_m2s_rings = args->num_m2s_rings;
+  conn->args.buffer_size = args->buffer_size;
+  conn->args.log2_ring_size = args->log2_ring_size;
+  conn->args.is_master = args->is_master;
+  conn->args.mode = args->mode;
+  conn->msg_queue = NULL;
+  conn->regions = NULL;
+  conn->tx_queues = NULL;
+  conn->rx_queues = NULL;
+  conn->fd = -1;
+  conn->on_connect = on_connect;
+  conn->on_disconnect = on_disconnect;
+  conn->on_interrupt = on_interrupt;
+  conn->private_ctx = private_ctx;
+  memset (&conn->run_args, 0, sizeof (memif_conn_run_args_t));
+
+  uint8_t l = strlen ((char *) args->interface_name);
+  strncpy ((char *) conn->args.interface_name, (char *) args->interface_name,
+	   l);
+
+  l = strlen ((char *) args->instance_name);
+  strncpy ((char *) conn->args.instance_name, (char *) args->instance_name,
+	   l);
+
+  /* allocate and initialize socket_filename so it can be copyed to sun_path
+     without memory leaks */
+  conn->args.socket_filename = malloc (sizeof (char *) * 108);
+  memset (conn->args.socket_filename, 0, 108 * sizeof (char *));
+
+  if (args->socket_filename)
+    {
+      if (conn->args.socket_filename == NULL)
+	{
+	  err = memif_syscall_error_handler (errno);
+	  goto error;
+	}
+      strncpy ((char *) conn->args.socket_filename,
+	       (char *) args->socket_filename,
+	       strlen ((char *) args->socket_filename));
+    }
+  else
+    {
+      uint16_t sdl = strlen (MEMIF_DEFAULT_SOCKET_DIR);
+      uint16_t sfl = strlen (MEMIF_DEFAULT_SOCKET_FILENAME);
+      if (conn->args.socket_filename == NULL)
+	{
+	  err = memif_syscall_error_handler (errno);
+	  goto error;
+	}
+      strncpy ((char *) conn->args.socket_filename,
+	       MEMIF_DEFAULT_SOCKET_DIR, sdl);
+      conn->args.socket_filename[sdl] = '/';
+      strncpy ((char *) (conn->args.socket_filename + 1 + sdl),
+	       MEMIF_DEFAULT_SOCKET_FILENAME, sfl);
+    }
+
+  if (args->secret)
+    {
+      l = strlen ((char *) args->secret);
+      strncpy ((char *) conn->args.secret, (char *) args->secret, l);
+    }
+
+  if (conn->args.is_master)
+    {
+      conn->run_args.buffer_size = conn->args.buffer_size;
+      memif_socket_t *ms;
+      memif_list_elt_t elt;
+      for (i = 0; i < lm->listener_list_len; i++)
+	{
+	  if ((ms =
+	       (memif_socket_t *) lm->listener_list[i].data_struct) != NULL)
+	    {
+	      if (strncmp
+		  ((char *) ms->filename, (char *) conn->args.socket_filename,
+		   strlen ((char *) ms->filename)) == 0)
+		{
+		  /* add interface to listener socket */
+		  elt.key = conn->args.interface_id;
+		  *c = elt.data_struct = conn;
+		  add_list_elt (&elt, &ms->interface_list,
+				&ms->interface_list_len);
+		  ms->use_count++;
+		  conn->listener_fd = ms->fd;
+		  break;
+		}
+	    }
+	  else
+	    {
+	      struct stat file_stat;
+	      if (stat ((char *) conn->args.socket_filename, &file_stat) == 0)
+		{
+		  if (S_ISSOCK (file_stat.st_mode))
+		    unlink ((char *) conn->args.socket_filename);
+		  else
+		    return memif_syscall_error_handler (errno);
+		}
+	      DBG ("creating socket file");
+	      ms = malloc (sizeof (memif_socket_t));
+	      ms->filename = malloc (strlen ((char *) conn->args.
+					     socket_filename) +
+				     sizeof (char));
+	      memset (ms->filename, 0,
+		      strlen ((char *) conn->args.socket_filename) +
+		      sizeof (char));
+	      strncpy ((char *) ms->filename,
+		       (char *) conn->args.socket_filename,
+		       strlen ((char *) conn->args.socket_filename));
+	      ms->interface_list_len = 1;
+	      ms->interface_list =
+		malloc (sizeof (memif_list_elt_t) * ms->interface_list_len);
+	      ms->interface_list[0].key = -1;
+	      ms->interface_list[0].data_struct = NULL;
+	      struct sockaddr_un un = { 0 };
+	      int on = 1;
+
+	      ms->fd = socket (AF_UNIX, SOCK_SEQPACKET, 0);
+	      if (ms->fd < 0)
+		{
+		  err = memif_syscall_error_handler (errno);
+		  goto error;
+		}
+	      DBG ("socket %d created", ms->fd);
+	      un.sun_family = AF_UNIX;
+	      strncpy ((char *) un.sun_path, (char *) ms->filename,
+		       sizeof (un.sun_path) - 1);
+	      DBG ("sockopt");
+	      if (setsockopt
+		  (ms->fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof (on)) < 0)
+		{
+		  err = memif_syscall_error_handler (errno);
+		  goto error;
+		}
+	      DBG ("bind");
+	      if (bind (ms->fd, (struct sockaddr *) &un, sizeof (un)) < 0)
+		{
+		  err = memif_syscall_error_handler (errno);
+		  goto error;
+		}
+	      DBG ("listen");
+	      if (listen (ms->fd, 1) < 0)
+		{
+		  err = memif_syscall_error_handler (errno);
+		  goto error;
+		}
+	      DBG ("stat");
+	      if (stat ((char *) ms->filename, &file_stat) < 0)
+		{
+		  err = memif_syscall_error_handler (errno);
+		  goto error;
+		}
+
+	      /* add interface to listener socket */
+	      elt.key = conn->args.interface_id;
+	      *c = elt.data_struct = conn;
+	      add_list_elt (&elt, &ms->interface_list,
+			    &ms->interface_list_len);
+	      ms->use_count = 1;
+	      conn->listener_fd = ms->fd;
+
+	      /* add listener socket to libmemif main */
+	      elt.key = ms->fd;
+	      elt.data_struct = ms;
+	      add_list_elt (&elt, &lm->listener_list, &lm->listener_list_len);
+	      lm->control_fd_update (ms->fd, MEMIF_FD_EVENT_READ);
+	      break;
+	    }
+	}
+    }
+  else
+    {
+      if (lm->disconn_slaves == 0)
+	{
+	  if (timerfd_settime (lm->timerfd, 0, &lm->arm, NULL) < 0)
+	    {
+	      err = memif_syscall_error_handler (errno);
+	      goto error;
+	    }
+	}
+
+      lm->disconn_slaves++;
+
+      list_elt.key = -1;
+      *c = list_elt.data_struct = conn;
+      if ((index =
+	   add_list_elt (&list_elt, &lm->control_list,
+			 &lm->control_list_len)) < 0)
+	{
+	  err = MEMIF_ERR_NOMEM;
+	  goto error;
+	}
+    }
+
+  conn->index = index;
+
+  return 0;
+
+error:
+  if (sockfd > 0)
+    close (sockfd);
+  sockfd = -1;
+  if (conn->args.socket_filename)
+    free (conn->args.socket_filename);
+  if (conn != NULL)
+    free (conn);
+  *c = conn = NULL;
+  return err;
+}
+
+int
+memif_control_fd_handler (int fd, uint8_t events)
+{
+  int i, rv, sockfd = -1, err = MEMIF_ERR_SUCCESS;	/* 0 */
+  uint16_t num;
+  memif_list_elt_t *e = NULL;
+  memif_connection_t *conn;
+  libmemif_main_t *lm = &libmemif_main;
+  if (fd == lm->timerfd)
+    {
+      uint64_t b;
+      ssize_t size;
+      size = read (fd, &b, sizeof (b));
+      for (i = 0; i < lm->control_list_len; i++)
+	{
+	  if ((lm->control_list[i].key < 0)
+	      && (lm->control_list[i].data_struct != NULL))
+	    {
+	      conn = lm->control_list[i].data_struct;
+	      if (conn->args.is_master)
+		continue;
+
+	      struct sockaddr_un sun;
+	      sockfd = socket (AF_UNIX, SOCK_SEQPACKET, 0);
+	      if (sockfd < 0)
+		{
+		  err = memif_syscall_error_handler (errno);
+		  goto error;
+		}
+
+	      sun.sun_family = AF_UNIX;
+
+	      strncpy (sun.sun_path, conn->args.socket_filename,
+		       sizeof (sun.sun_path) - 1);
+
+	      if (connect (sockfd, (struct sockaddr *) &sun,
+			   sizeof (struct sockaddr_un)) == 0)
+		{
+		  conn->fd = sockfd;
+		  conn->read_fn = memif_conn_fd_read_ready;
+		  conn->write_fn = memif_conn_fd_write_ready;
+		  conn->error_fn = memif_conn_fd_error;
+
+		  lm->control_list[conn->index].key = conn->fd;
+
+		  lm->control_fd_update (sockfd,
+					 MEMIF_FD_EVENT_READ |
+					 MEMIF_FD_EVENT_WRITE);
+
+		  lm->disconn_slaves--;
+		  if (lm->disconn_slaves == 0)
+		    {
+		      if (timerfd_settime (lm->timerfd, 0, &lm->disarm, NULL)
+			  < 0)
+			{
+			  err = memif_syscall_error_handler (errno);
+			  goto error;
+			}
+		    }
+		}
+	      else
+		{
+		  err = memif_syscall_error_handler (errno);
+		  goto error;
+		}
+	    }
+	}
+    }
+  else
+    {
+      get_list_elt (&e, lm->interrupt_list, lm->interrupt_list_len, fd);
+      if (e != NULL)
+	{
+	  if (((memif_connection_t *) e->data_struct)->on_interrupt != NULL)
+	    {
+	      num =
+		(((memif_connection_t *) e->data_struct)->args.
+		 is_master) ? ((memif_connection_t *) e->data_struct)->
+		run_args.num_s2m_rings : ((memif_connection_t *) e->
+					  data_struct)->run_args.
+		num_m2s_rings;
+	      for (i = 0; i < num; i++)
+		{
+		  if (((memif_connection_t *) e->data_struct)->rx_queues[i].
+		      int_fd == fd)
+		    {
+		      ((memif_connection_t *) e->data_struct)->on_interrupt ((void *) e->data_struct, ((memif_connection_t *) e->data_struct)->private_ctx, i);
+		      return MEMIF_ERR_SUCCESS;
+		    }
+		}
+	    }
+	  return MEMIF_ERR_SUCCESS;
+	}
+      get_list_elt (&e, lm->listener_list, lm->listener_list_len, fd);
+      if (e != NULL)
+	{
+	  memif_conn_fd_accept_ready ((memif_socket_t *) e->data_struct);
+	  return MEMIF_ERR_SUCCESS;
+	}
+
+      get_list_elt (&e, lm->pending_list, lm->pending_list_len, fd);
+      if (e != NULL)
+	{
+	  memif_read_ready (fd);
+	  return MEMIF_ERR_SUCCESS;
+	}
+
+      get_list_elt (&e, lm->control_list, lm->control_list_len, fd);
+      if (e != NULL)
+	{
+	  if (events & MEMIF_FD_EVENT_READ)
+	    {
+	      err =
+		((memif_connection_t *) e->data_struct)->read_fn (e->
+								  data_struct);
+	      if (err != MEMIF_ERR_SUCCESS)
+		return err;
+	    }
+	  if (events & MEMIF_FD_EVENT_WRITE)
+	    {
+	      err =
+		((memif_connection_t *) e->data_struct)->write_fn (e->
+								   data_struct);
+	      if (err != MEMIF_ERR_SUCCESS)
+		return err;
+	    }
+	  if (events & MEMIF_FD_EVENT_ERROR)
+	    {
+	      err =
+		((memif_connection_t *) e->data_struct)->error_fn (e->
+								   data_struct);
+	      if (err != MEMIF_ERR_SUCCESS)
+		return err;
+	    }
+	}
+    }
+
+  return MEMIF_ERR_SUCCESS;	/* 0 */
+
+error:
+  if (sockfd > 0)
+    close (sockfd);
+  sockfd = -1;
+  return err;
+}
+
+int
+memif_poll_event (int timeout)
+{
+  libmemif_main_t *lm = &libmemif_main;
+  memif_list_elt_t *elt;
+  struct epoll_event evt, *e;
+  int en = 0, err = MEMIF_ERR_SUCCESS, i = 0;	/* 0 */
+  uint16_t num;
+  uint32_t events = 0;
+  memset (&evt, 0, sizeof (evt));
+  evt.events = EPOLLIN | EPOLLOUT;
+  sigset_t sigset;
+  sigemptyset (&sigset);
+  en = epoll_pwait (memif_epfd, &evt, 1, timeout, &sigset);
+  if (en < 0)
+    {
+      DBG ("epoll_pwait: %s", strerror (errno));
+      return -1;
+    }
+  if (en > 0)
+    {
+      if (evt.events & EPOLLIN)
+	events |= MEMIF_FD_EVENT_READ;
+      if (evt.events & EPOLLOUT)
+	events |= MEMIF_FD_EVENT_WRITE;
+      if (evt.events & EPOLLERR)
+	events |= MEMIF_FD_EVENT_ERROR;
+      err = memif_control_fd_handler (evt.data.fd, events);
+      return err;
+    }
+  return 0;
+}
+
+static void
+memif_msg_queue_free (memif_msg_queue_elt_t ** e)
+{
+  if (*e == NULL)
+    return;
+  memif_msg_queue_free (&(*e)->next);
+  free (*e);
+  *e = NULL;
+  return;
+}
+
+/* send disconnect msg and close interface */
+int
+memif_disconnect_internal (memif_connection_t * c)
+{
+  if (c == NULL)
+    {
+      DBG ("no connection");
+      return MEMIF_ERR_NOCONN;
+    }
+  uint16_t num;
+  int err = MEMIF_ERR_SUCCESS, i;	/* 0 */
+  memif_queue_t *mq;
+  libmemif_main_t *lm = &libmemif_main;
+  memif_list_elt_t *e;
+
+  c->on_disconnect ((void *) c, c->private_ctx);
+
+  if (c->fd > 0)
+    {
+      memif_msg_send_disconnect (c->fd, "interface deleted", 0);
+      lm->control_fd_update (c->fd, MEMIF_FD_EVENT_DEL);
+      close (c->fd);
+    }
+  get_list_elt (&e, lm->control_list, lm->control_list_len, c->fd);
+  if (e != NULL)
+    {
+      if (c->args.is_master)
+	free_list_elt (lm->control_list, lm->control_list_len, c->fd);
+      e->key = c->fd = -1;
+    }
+
+  if (c->tx_queues != NULL)
+    {
+      num =
+	(c->args.is_master) ? c->run_args.num_m2s_rings : c->run_args.
+	num_s2m_rings;
+      for (i = 0; i < num; i++)
+	{
+	  mq = &c->tx_queues[i];
+	  if (mq != NULL)
+	    {
+	      if (mq->int_fd > 0)
+		close (mq->int_fd);
+	      free_list_elt (lm->interrupt_list, lm->interrupt_list_len,
+			     mq->int_fd);
+	      mq->int_fd = -1;
+	    }
+	}
+      free (c->tx_queues);
+      c->tx_queues = NULL;
+    }
+
+  if (c->rx_queues != NULL)
+    {
+      num =
+	(c->args.is_master) ? c->run_args.num_s2m_rings : c->run_args.
+	num_m2s_rings;
+      for (i = 0; i < num; i++)
+	{
+	  mq = &c->rx_queues[i];
+	  if (mq != NULL)
+	    {
+	      if (mq->int_fd > 0)
+		{
+		  if (c->on_interrupt != NULL)
+		    lm->control_fd_update (mq->int_fd, MEMIF_FD_EVENT_DEL);
+		  close (mq->int_fd);
+		}
+	      free_list_elt (lm->interrupt_list, lm->interrupt_list_len,
+			     mq->int_fd);
+	      mq->int_fd = -1;
+	    }
+	}
+      free (c->rx_queues);
+      c->rx_queues = NULL;
+    }
+
+  if (c->regions != NULL)
+    {
+      if (munmap (c->regions[0].shm, c->regions[0].region_size) < 0)
+	return memif_syscall_error_handler (errno);
+      if (c->regions[0].fd > 0)
+	close (c->regions[0].fd);
+      c->regions[0].fd = -1;
+      free (c->regions);
+      c->regions = NULL;
+    }
+
+  memset (&c->run_args, 0, sizeof (memif_conn_run_args_t));
+
+  memif_msg_queue_free (&c->msg_queue);
+
+  if (!(c->args.is_master))
+    {
+      if (lm->disconn_slaves == 0)
+	{
+	  if (timerfd_settime (lm->timerfd, 0, &lm->arm, NULL) < 0)
+	    {
+	      err = memif_syscall_error_handler (errno);
+	      DBG_UNIX ("timerfd_settime: arm");
+	    }
+	}
+      lm->disconn_slaves++;
+    }
+
+  return err;
+}
+
+int
+memif_delete (memif_conn_handle_t * conn)
+{
+  memif_connection_t *c = (memif_connection_t *) * conn;
+  if (c == NULL)
+    {
+      DBG ("no connection");
+      return MEMIF_ERR_NOCONN;
+    }
+  libmemif_main_t *lm = &libmemif_main;
+  memif_list_elt_t *e = NULL;
+  memif_socket_t *ms = NULL;
+
+  int err = MEMIF_ERR_SUCCESS;
+
+  if (c->fd > 0)
+    {
+      DBG ("DISCONNECTING");
+      err = memif_disconnect_internal (c);
+      if (err == MEMIF_ERR_NOCONN)
+	return err;
+    }
+
+  free_list_elt_ctx (lm->control_list, lm->control_list_len, c);
+
+  if (c->args.is_master)
+    {
+      get_list_elt (&e, lm->listener_list, lm->listener_list_len,
+		    c->listener_fd);
+      if (e != NULL)
+	{
+	  ms = (memif_socket_t *) e->data_struct;
+	  ms->use_count--;
+	  free_list_elt (ms->interface_list, ms->interface_list_len,
+			 c->args.interface_id);
+	  if (ms->use_count <= 0)
+	    {
+	      lm->control_fd_update (c->listener_fd, MEMIF_FD_EVENT_DEL);
+	      free_list_elt (lm->listener_list, lm->listener_list_len,
+			     c->listener_fd);
+	      close (c->listener_fd);
+	      c->listener_fd = ms->fd = -1;
+	      free (ms->interface_list);
+	      ms->interface_list = NULL;
+	      free (ms->filename);
+	      ms->filename = NULL;
+	      free (ms);
+	      ms = NULL;
+	    }
+	}
+    }
+  else
+    {
+      lm->disconn_slaves--;
+      if (lm->disconn_slaves <= 0)
+	{
+	  if (timerfd_settime (lm->timerfd, 0, &lm->disarm, NULL) < 0)
+	    {
+	      err = memif_syscall_error_handler (errno);
+	      DBG ("timerfd_settime: disarm");
+	    }
+	}
+    }
+
+  if (c->args.socket_filename)
+    free (c->args.socket_filename);
+  c->args.socket_filename = NULL;
+
+  free (c);
+  c = NULL;
+
+  *conn = c;
+  return err;
+}
+
+int
+memif_connect1 (memif_connection_t * c)
+{
+  libmemif_main_t *lm = &libmemif_main;
+  memif_region_t *mr = c->regions;
+  memif_queue_t *mq;
+  int i;
+  uint16_t num;
+
+  if (mr != NULL)
+    {
+      if (!mr->shm)
+	{
+	  if (mr->fd < 0)
+	    return MEMIF_ERR_NO_SHMFD;
+
+	  if ((mr->shm = mmap (NULL, mr->region_size, PROT_READ | PROT_WRITE,
+			       MAP_SHARED, mr->fd, 0)) == MAP_FAILED)
+	    {
+	      return memif_syscall_error_handler (errno);
+	    }
+	}
+    }
+
+  num =
+    (c->args.is_master) ? c->run_args.num_m2s_rings : c->run_args.
+    num_s2m_rings;
+  for (i = 0; i < num; i++)
+    {
+      mq = &c->tx_queues[i];
+      if (mq != NULL)
+	{
+	  mq->ring = c->regions[mq->region].shm + mq->offset;
+	  if (mq->ring->cookie != MEMIF_COOKIE)
+	    {
+	      DBG ("wrong cookie on tx ring %u", i);
+	      return MEMIF_ERR_COOKIE;
+	    }
+	  mq->ring->head = mq->ring->tail = mq->last_head = mq->alloc_bufs =
+	    0;
+	}
+    }
+  num =
+    (c->args.is_master) ? c->run_args.num_s2m_rings : c->run_args.
+    num_m2s_rings;
+  for (i = 0; i < num; i++)
+    {
+      mq = &c->rx_queues[i];
+      if (mq != NULL)
+	{
+	  mq->ring = c->regions[mq->region].shm + mq->offset;
+	  if (mq->ring->cookie != MEMIF_COOKIE)
+	    {
+	      DBG ("wrong cookie on rx ring %u", i);
+	      return MEMIF_ERR_COOKIE;
+	    }
+	  mq->ring->head = mq->ring->tail = mq->last_head = mq->alloc_bufs =
+	    0;
+	}
+    }
+
+  lm->control_fd_update (c->fd, MEMIF_FD_EVENT_READ | MEMIF_FD_EVENT_MOD);
+
+  return 0;
+}
+
+int
+memif_init_regions_and_queues (memif_connection_t * conn)
+{
+  memif_ring_t *ring = NULL;
+  uint64_t buffer_offset;
+  memif_region_t *r;
+  int i, j;
+  libmemif_main_t *lm = &libmemif_main;
+  memif_list_elt_t e;
+
+  conn->regions = (memif_region_t *) malloc (sizeof (memif_region_t));
+  if (conn->regions == NULL)
+    return memif_syscall_error_handler (errno);
+  r = conn->regions;
+
+  buffer_offset =
+    (conn->run_args.num_s2m_rings +
+     conn->run_args.num_m2s_rings) * (sizeof (memif_ring_t) +
+				      sizeof (memif_desc_t) *
+				      (1 << conn->run_args.log2_ring_size));
+
+  r->region_size = buffer_offset +
+    conn->run_args.buffer_size * (1 << conn->run_args.log2_ring_size) *
+    (conn->run_args.num_s2m_rings + conn->run_args.num_m2s_rings);
+
+  if ((r->fd = memfd_create ("memif region 0", MFD_ALLOW_SEALING)) == -1)
+    return memif_syscall_error_handler (errno);
+/*
+    if ((fcntl (r->fd, F_ADD_SEALS, F_SEAL_SHRINK)) == -1)
+        return memif_syscall_error_handler (errno);
+*/
+  if ((ftruncate (r->fd, r->region_size)) == -1)
+    return memif_syscall_error_handler (errno);
+
+  if ((r->shm = mmap (NULL, r->region_size, PROT_READ | PROT_WRITE,
+		      MAP_SHARED, r->fd, 0)) == MAP_FAILED)
+    return memif_syscall_error_handler (errno);
+
+  for (i = 0; i < conn->run_args.num_s2m_rings; i++)
+    {
+      ring = memif_get_ring (conn, MEMIF_RING_S2M, i);
+      DBG ("RING: %p I: %d", ring, i);
+      ring->head = ring->tail = 0;
+      ring->cookie = MEMIF_COOKIE;
+      ring->flags = 0;
+      for (j = 0; j < (1 << conn->run_args.log2_ring_size); j++)
+	{
+	  uint16_t slot = i * (1 << conn->run_args.log2_ring_size) + j;
+	  ring->desc[j].region = 0;
+	  ring->desc[j].offset = buffer_offset +
+	    (uint32_t) (slot * conn->run_args.buffer_size);
+	  ring->desc[j].buffer_length = conn->run_args.buffer_size;
+	}
+    }
+  for (i = 0; i < conn->run_args.num_m2s_rings; i++)
+    {
+      ring = memif_get_ring (conn, MEMIF_RING_M2S, i);
+      DBG ("RING: %p I: %d", ring, i);
+      ring->head = ring->tail = 0;
+      ring->cookie = MEMIF_COOKIE;
+      ring->flags = 0;
+      for (j = 0; j < (1 << conn->run_args.log2_ring_size); j++)
+	{
+	  uint16_t slot =
+	    (i +
+	     conn->run_args.num_s2m_rings) *
+	    (1 << conn->run_args.log2_ring_size) + j;
+	  ring->desc[j].region = 0;
+	  ring->desc[j].offset = buffer_offset +
+	    (uint32_t) (slot * conn->run_args.buffer_size);
+	  ring->desc[j].buffer_length = conn->run_args.buffer_size;
+	}
+    }
+  memif_queue_t *mq;
+  mq =
+    (memif_queue_t *) malloc (sizeof (memif_queue_t) *
+			      conn->run_args.num_s2m_rings);
+  if (mq == NULL)
+    return memif_syscall_error_handler (errno);
+  int x;
+  for (x = 0; x < conn->run_args.num_s2m_rings; x++)
+    {
+      if ((mq[x].int_fd = eventfd (0, EFD_NONBLOCK)) < 0)
+	return memif_syscall_error_handler (errno);
+      /* add int fd to interrupt fd list */
+      e.key = mq[x].int_fd;
+      e.data_struct = conn;
+      add_list_elt (&e, &lm->interrupt_list, &lm->interrupt_list_len);
+
+      mq[x].ring = memif_get_ring (conn, MEMIF_RING_S2M, x);
+      DBG ("RING: %p I: %d", mq[x].ring, x);
+      mq[x].log2_ring_size = conn->run_args.log2_ring_size;
+      mq[x].region = 0;
+      mq[x].offset =
+	(void *) mq[x].ring - (void *) conn->regions[mq->region].shm;
+      mq[x].last_head = 0;
+      mq[x].alloc_bufs = 0;
+    }
+  conn->tx_queues = mq;
+
+  mq =
+    (memif_queue_t *) malloc (sizeof (memif_queue_t) *
+			      conn->run_args.num_m2s_rings);
+  if (mq == NULL)
+    return memif_syscall_error_handler (errno);
+  for (x = 0; x < conn->run_args.num_m2s_rings; x++)
+    {
+      if ((mq[x].int_fd = eventfd (0, EFD_NONBLOCK)) < 0)
+	return memif_syscall_error_handler (errno);
+      /* add int fd to interrupt fd list */
+      e.key = mq[x].int_fd;
+      e.data_struct = conn;
+      add_list_elt (&e, &lm->interrupt_list, &lm->interrupt_list_len);
+
+      mq[x].ring = memif_get_ring (conn, MEMIF_RING_M2S, x);
+      DBG ("RING: %p I: %d", mq[x].ring, x);
+      mq[x].log2_ring_size = conn->run_args.log2_ring_size;
+      mq[x].region = 0;
+      mq[x].offset =
+	(void *) mq[x].ring - (void *) conn->regions[mq->region].shm;
+      mq[x].last_head = 0;
+      mq[x].alloc_bufs = 0;
+    }
+  conn->rx_queues = mq;
+
+  return 0;
+}
+
+int
+memif_buffer_alloc (memif_conn_handle_t conn, uint16_t qid,
+		    memif_buffer_t * bufs, uint16_t count,
+		    uint16_t * count_out)
+{
+  memif_connection_t *c = (memif_connection_t *) conn;
+  if (c == NULL)
+    return MEMIF_ERR_NOCONN;
+  if (c->fd < 0)
+    return MEMIF_ERR_DISCONNECTED;
+  uint8_t num =
+    (c->args.is_master) ? c->run_args.num_m2s_rings : c->run_args.
+    num_s2m_rings;
+  if (qid >= num)
+    return MEMIF_ERR_QID;
+  memif_queue_t *mq = &c->tx_queues[qid];
+  memif_ring_t *ring = mq->ring;
+  memif_buffer_t *b0, *b1;
+  uint16_t mask = (1 << mq->log2_ring_size) - 1;
+  uint16_t s0, s1, ns;
+  *count_out = 0;
+  int err = MEMIF_ERR_SUCCESS;	/* 0 */
+
+  if (ring->tail != ring->head)
+    {
+      if (ring->head > ring->tail)
+	ns = (1 << mq->log2_ring_size) - ring->head + ring->tail;
+      else
+	ns = ring->tail - ring->head;
+    }
+  else
+    ns = (1 << mq->log2_ring_size);
+
+  /* (head == tail) ? receive function will asume that no packets are available */
+  ns -= 1;
+
+  while (count && ns)
+    {
+      while ((count > 2) && (ns > 2))
+	{
+	  s0 = (ring->head + mq->alloc_bufs + *count_out) & mask;
+	  s1 = (ring->head + mq->alloc_bufs + *count_out + 1) & mask;
+
+	  b0 = (bufs + *count_out);
+	  b1 = (bufs + *count_out + 1);
+
+	  b0->desc_index = s0;
+	  b1->desc_index = s1;
+	  b0->buffer_len = ring->desc[s0].buffer_length;
+	  b1->buffer_len = ring->desc[s1].buffer_length;
+	  /* TODO: support multiple regions -> ring descriptor contains region index */
+	  b0->data = c->regions->shm + ring->desc[s0].offset;
+	  b1->data = c->regions->shm + ring->desc[s1].offset;
+
+	  DBG ("allocated ring slots %u, %u", s0, s1);
+	  count -= 2;
+	  ns -= 2;
+	  *count_out += 2;
+	}
+      s0 = (ring->head + mq->alloc_bufs + *count_out) & mask;
+
+      b0 = (bufs + *count_out);
+
+      b0->desc_index = s0;
+      b0->buffer_len = ring->desc[s0].buffer_length;
+      b0->data = c->regions->shm + ring->desc[s0].offset;
+
+      DBG ("allocated ring slot %u", s0);
+      count--;
+      ns--;
+      *count_out += 1;
+    }
+
+  mq->alloc_bufs += *count_out;
+  DBG ("allocated: %u/%u bufs. Total %u allocated bufs", *count_out, count,
+       mq->alloc_bufs);
+
+  if (count)
+    {
+      DBG ("ring buffer full! qid: %u", qid);
+      err = MEMIF_ERR_NOBUF_RING;
+    }
+
+  return err;
+}
+
+int
+memif_buffer_free (memif_conn_handle_t conn, uint16_t qid,
+		   memif_buffer_t * bufs, uint16_t count,
+		   uint16_t * count_out)
+{
+  memif_connection_t *c = (memif_connection_t *) conn;
+  if (c == NULL)
+    return MEMIF_ERR_NOCONN;
+  if (c->fd < 0)
+    return MEMIF_ERR_DISCONNECTED;
+  uint8_t num =
+    (c->args.is_master) ? c->run_args.num_s2m_rings : c->run_args.
+    num_m2s_rings;
+  if (qid >= num)
+    return MEMIF_ERR_QID;
+  libmemif_main_t *lm = &libmemif_main;
+  memif_queue_t *mq = &c->rx_queues[qid];
+  memif_ring_t *ring = mq->ring;
+  uint16_t tail = ring->tail;
+  uint16_t mask = (1 << mq->log2_ring_size) - 1;
+  memif_buffer_t *b0, *b1;
+  *count_out = 0;
+
+  if (mq->alloc_bufs < count)
+    count = mq->alloc_bufs;
+
+  while (count)
+    {
+      while (count > 2)
+	{
+	  b0 = (bufs + *count_out);
+	  b1 = (bufs + *count_out + 1);
+	  tail = (b0->desc_index + 1) & mask;
+	  tail = (b1->desc_index + 1) & mask;
+	  b0->data = NULL;
+	  b1->data = NULL;
+
+	  count -= 2;
+	  *count_out += 2;
+	  mq->alloc_bufs -= 2;
+	}
+      b0 = (bufs + *count_out);
+      tail = (b0->desc_index + 1) & mask;
+      b0->data = NULL;
+
+      count--;
+      *count_out += 1;
+      mq->alloc_bufs--;
+    }
+  MEMIF_MEORY_BARRIER ();
+  ring->tail = tail;
+
+  return MEMIF_ERR_SUCCESS;	/* 0 */
+}
+
+int
+memif_tx_burst (memif_conn_handle_t conn, uint16_t qid,
+		memif_buffer_t * bufs, uint16_t count, uint16_t * tx)
+{
+  memif_connection_t *c = (memif_connection_t *) conn;
+  if (c == NULL)
+    return MEMIF_ERR_NOCONN;
+  if (c->fd < 0)
+    return MEMIF_ERR_DISCONNECTED;
+  uint8_t num =
+    (c->args.is_master) ? c->run_args.num_m2s_rings : c->run_args.
+    num_s2m_rings;
+  if (qid >= num)
+    return MEMIF_ERR_QID;
+  memif_queue_t *mq = &c->tx_queues[qid];
+  memif_ring_t *ring = mq->ring;
+  uint16_t head = ring->head;
+  uint16_t mask = (1 << mq->log2_ring_size) - 1;
+  *tx = 0;
+  memif_buffer_t *b0, *b1;
+
+  while (count)
+    {
+      while (count > 2)
+	{
+	  b0 = (bufs + *tx);
+	  b1 = (bufs + *tx + 1);
+	  ring->desc[b0->desc_index].length = b0->data_len;
+	  ring->desc[b1->desc_index].length = b1->data_len;
+
+#ifdef MEMIF_DBG_SHM
+	  print_bytes (b0->data, b0->data_len, DBG_TX_BUF);
+	  print_bytes (b1->data, b1->data_len, DBG_TX_BUF);
+#endif
+
+	  head = (b0->desc_index + 1) & mask;
+	  head = (b1->desc_index + 1) & mask;
+
+	  b0->data = NULL;
+	  b0->data_len = 0;
+	  b1->data = NULL;
+	  b1->data_len = 0;
+
+	  count -= 2;
+	  *tx += 2;
+	}
+
+      b0 = (bufs + *tx);
+      ring->desc[b0->desc_index].length = b0->data_len;
+
+#ifdef MEMIF_DBG_SHM
+      print_bytes (b0->data, b0->data_len, DBG_TX_BUF);
+#endif
+
+      head = (b0->desc_index + 1) & mask;
+
+      b0->data = NULL;
+      b0->data_len = 0;
+
+      count--;
+      *tx += 1;
+    }
+  MEMIF_MEORY_BARRIER ();
+  ring->head = head;
+
+  mq->alloc_bufs -= *tx;
+
+  if ((ring->flags & MEMIF_RING_FLAG_MASK_INT) == 0)
+    {
+      uint64_t a = 1;
+      int r = write (mq->int_fd, &a, sizeof (a));
+      if (r < 0)
+	return MEMIF_ERR_INT_WRITE;
+    }
+
+  return MEMIF_ERR_SUCCESS;	/* 0 */
+}
+
+int
+memif_rx_burst (memif_conn_handle_t conn, uint16_t qid,
+		memif_buffer_t * bufs, uint16_t count, uint16_t * rx)
+{
+  memif_connection_t *c = (memif_connection_t *) conn;
+  if (c == NULL)
+    return MEMIF_ERR_NOCONN;
+  if (c->fd < 0)
+    return MEMIF_ERR_DISCONNECTED;
+  uint8_t num =
+    (c->args.is_master) ? c->run_args.num_s2m_rings : c->run_args.
+    num_m2s_rings;
+  if (qid >= num)
+    return MEMIF_ERR_QID;
+  memif_queue_t *mq = &c->rx_queues[qid];
+  memif_ring_t *ring = mq->ring;
+  uint16_t head = ring->head;
+  uint16_t ns;
+  uint16_t mask = (1 << mq->log2_ring_size) - 1;
+  memif_buffer_t *b0, *b1;
+  *rx = 0;
+
+  uint64_t b;
+  ssize_t r = read (mq->int_fd, &b, sizeof (b));
+  if ((r == -1) && (errno != EAGAIN))
+    return memif_syscall_error_handler (errno);
+
+  if (head == mq->last_head)
+    return 0;
+
+  if (head > mq->last_head)
+    ns = head - mq->last_head;
+  else
+    ns = (1 << mq->log2_ring_size) - mq->last_head + head;
+
+  while (ns && count)
+    {
+      while ((ns > 2) && (count > 2))
+	{
+	  b0 = (bufs + *rx);
+	  b1 = (bufs + *rx + 1);
+
+	  b0->desc_index = mq->last_head;
+	  b1->desc_index = mq->last_head + 1;
+	  b0->data = memif_get_buffer (conn, ring, mq->last_head);
+	  b1->data = memif_get_buffer (conn, ring, mq->last_head + 1);
+	  b0->data_len = ring->desc[mq->last_head].length;
+	  b1->data_len = ring->desc[mq->last_head + 1].length;
+	  b0->buffer_len = ring->desc[mq->last_head].buffer_length;
+	  b1->buffer_len = ring->desc[mq->last_head + 1].buffer_length;
+
+#ifdef MEMIF_DBG_SHM
+	  print_bytes (b0->data, b0->data_len, DBG_RX_BUF);
+	  print_bytes (b1->data, b1->data_len, DBG_RX_BUF);
+#endif
+
+	  mq->last_head = (mq->last_head + 2) & mask;
+
+	  ns -= 2;
+	  count -= 2;
+	  *rx += 2;
+	}
+      b0 = (bufs + *rx);
+
+      b0->desc_index = mq->last_head;
+      b0->data = memif_get_buffer (conn, ring, mq->last_head);
+      b0->data_len = ring->desc[mq->last_head].length;
+      b0->buffer_len = ring->desc[mq->last_head].buffer_length;
+
+#ifdef MEMIF_DBG_SHM
+      print_bytes (b0->data, b0->data_len, DBG_RX_BUF);
+#endif
+
+      mq->last_head = (mq->last_head + 1) & mask;
+
+      ns--;
+      count--;
+      *rx += 1;
+    }
+
+  mq->alloc_bufs += *rx;
+
+  if (ns)
+    {
+      DBG ("not enough buffers!");
+      return MEMIF_ERR_NOBUF;
+    }
+
+  return MEMIF_ERR_SUCCESS;	/* 0 */
+}
+
+int
+memif_get_details (memif_conn_handle_t conn, memif_details_t * md,
+		   char *buf, ssize_t buflen)
+{
+  memif_connection_t *c = (memif_connection_t *) conn;
+  if (c == NULL)
+    return MEMIF_ERR_NOCONN;
+
+  int err = MEMIF_ERR_SUCCESS, i;
+  ssize_t l0, l1, total_l;
+  l0 = 0;
+
+  l1 = strlen ((char *) c->args.interface_name);
+  if (l0 + l1 <= buflen)
+    {
+      md->if_name = strncpy (buf + l0, (char *) c->args.interface_name, l1);
+      md->if_name[l0 + l1] = '\0';
+      l0 += l1 + 1;
+    }
+  else
+    err = MEMIF_ERR_NOBUF_DET;
+
+  l1 = strlen ((char *) c->args.instance_name);
+  if (l0 + l1 <= buflen)
+    {
+      md->inst_name = strncpy (buf + l0, (char *) c->args.instance_name, l1);
+      md->inst_name[l0 + l1] = '\0';
+      l0 += l1 + 1;
+    }
+  else
+    err = MEMIF_ERR_NOBUF_DET;
+
+  l1 = strlen ((char *) c->remote_if_name);
+  if (l0 + l1 <= buflen)
+    {
+      md->remote_if_name = strncpy (buf + l0, (char *) c->remote_if_name, l1);
+      md->remote_if_name[l0 + l1] = '\0';
+      l0 += l1 + 1;
+    }
+  else
+    err = MEMIF_ERR_NOBUF_DET;
+
+  l1 = strlen ((char *) c->remote_name);
+  if (l0 + l1 <= buflen)
+    {
+      md->remote_inst_name = strncpy (buf + l0, (char *) c->remote_name, l1);
+      md->remote_inst_name[l0 + l1] = '\0';
+      l0 += l1 + 1;
+    }
+  else
+    err = MEMIF_ERR_NOBUF_DET;
+
+  md->id = c->args.interface_id;
+
+  if (c->args.secret)
+    {
+      l1 = strlen ((char *) c->args.secret);
+      md->secret = strncpy (buf + l0, (char *) c->args.secret, l1);
+      md->secret[l0 + l1] = '\0';
+      l0 += l1 + 1;
+    }
+  else
+    err = MEMIF_ERR_NOBUF_DET;
+
+  md->role = (c->args.is_master) ? 0 : 1;
+  md->mode = c->args.mode;
+
+  l1 = strlen ((char *) c->args.socket_filename);
+  if (l0 + l1 <= buflen)
+    {
+      md->socket_filename =
+	strncpy (buf + l0, (char *) c->args.socket_filename, l1);
+      md->socket_filename[l0 + l1] = '\0';
+      l0 += l1 + 1;
+    }
+  else
+    err = MEMIF_ERR_NOBUF_DET;
+
+  md->rx_queues_num =
+    (c->args.is_master) ? c->run_args.num_s2m_rings : c->run_args.
+    num_m2s_rings;
+
+  l1 = sizeof (memif_queue_details_t) * md->rx_queues_num;
+  if (l0 + l1 <= buflen)
+    {
+      md->rx_queues = (memif_queue_details_t *) buf + l0;
+      l0 = l1 + 1;
+    }
+  else
+    err = MEMIF_ERR_NOBUF_DET;
+
+  for (i = 0; i < md->rx_queues_num; i++)
+    {
+      md->rx_queues[i].qid = i;
+      md->rx_queues[i].ring_size = (1 << c->rx_queues[i].log2_ring_size);
+      md->rx_queues[i].buffer_size = c->run_args.buffer_size;
+    }
+
+  md->tx_queues_num =
+    (c->args.is_master) ? c->run_args.num_m2s_rings : c->run_args.
+    num_s2m_rings;
+
+  l1 = sizeof (memif_queue_details_t) * md->tx_queues_num;
+  if (l0 + l1 <= buflen)
+    {
+      md->tx_queues = (memif_queue_details_t *) buf + l0;
+      l0 = l1 + 1;
+    }
+  else
+    err = MEMIF_ERR_NOBUF_DET;
+
+  for (i = 0; i < md->tx_queues_num; i++)
+    {
+      md->tx_queues[i].qid = i;
+      md->tx_queues[i].ring_size = (1 << c->tx_queues[i].log2_ring_size);
+      md->tx_queues[i].buffer_size = c->run_args.buffer_size;
+    }
+
+  md->link_up_down = (c->fd > 0) ? 1 : 0;
+
+  return err;			/* 0 */
+}
+
+int
+memif_get_queue_efd (memif_conn_handle_t conn, uint16_t qid, int *efd)
+{
+  memif_connection_t *c = (memif_connection_t *) conn;
+  *efd = -1;
+  if (c == NULL)
+    return MEMIF_ERR_NOCONN;
+  if (c->fd < 0)
+    return MEMIF_ERR_DISCONNECTED;
+  uint8_t num =
+    (c->args.is_master) ? c->run_args.num_s2m_rings : c->run_args.
+    num_m2s_rings;
+  if (qid >= num)
+    return MEMIF_ERR_QID;
+
+  *efd = c->rx_queues[qid].int_fd;
+
+  return MEMIF_ERR_SUCCESS;
+}
+
+int
+memif_cleanup ()
+{
+  libmemif_main_t *lm = &libmemif_main;
+  if (lm->app_name)
+    free (lm->app_name);
+  lm->app_name = NULL;
+  if (lm->control_list)
+    free (lm->control_list);
+  lm->control_list = NULL;
+  if (lm->interrupt_list)
+    free (lm->interrupt_list);
+  lm->interrupt_list = NULL;
+  if (lm->listener_list)
+    free (lm->listener_list);
+  lm->listener_list = NULL;
+  if (lm->pending_list)
+    free (lm->pending_list);
+  lm->pending_list = NULL;
+
+  return MEMIF_ERR_SUCCESS;	/* 0 */
+}