Add memif - packet memory interface for intra-host communication

Change-Id: I94c06b07a39f07ceba87bf3e7fcfc70e43231e8a
Signed-off-by: Damjan Marion <damarion@cisco.com>
Co-Authored-By: Milan Lenco <Milan.Lenco@pantheon.tech>

1 files changed, 1045 insertions, 0 deletions

diff --git a/src/plugins/memif/memif.c b/src/plugins/memif/memif.c
new file mode 100644
index 00000000000..7ba67c5b898
--- /dev/null
+++ b/src/plugins/memif/memif.c
@@ -0,0 +1,1045 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2016 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.
+ *------------------------------------------------------------------
+ */
+
+#define _GNU_SOURCE
+#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 <vlib/vlib.h>
+#include <vlib/unix/unix.h>
+#include <vnet/plugin/plugin.h>
+#include <vnet/ethernet/ethernet.h>
+#include <vpp/app/version.h>
+#include <memif/memif.h>
+
+#define MEMIF_DEBUG 1
+
+#if MEMIF_DEBUG == 1
+#define DEBUG_LOG(...) clib_warning(__VA_ARGS__)
+#define DEBUG_UNIX_LOG(...) clib_unix_warning(__VA_ARGS__)
+#else
+#define DEBUG_LOG(...)
+#endif
+
+memif_main_t memif_main;
+
+static clib_error_t *memif_conn_fd_read_ready (unix_file_t * uf);
+static clib_error_t *memif_int_fd_read_ready (unix_file_t * uf);
+
+static u32
+memif_eth_flag_change (vnet_main_t * vnm, vnet_hw_interface_t * hi, u32 flags)
+{
+  /* nothing for now */
+  return 0;
+}
+
+static void
+memif_remove_pending_conn (memif_pending_conn_t * pending_conn)
+{
+  memif_main_t *mm = &memif_main;
+
+  unix_file_del (&unix_main,
+		 unix_main.file_pool + pending_conn->connection.index);
+  pool_put (mm->pending_conns, pending_conn);
+}
+
+static void
+memif_connect (vlib_main_t * vm, memif_if_t * mif)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  int num_rings = mif->num_s2m_rings + mif->num_m2s_rings;
+  memif_ring_data_t *rd = NULL;
+
+  vec_validate_aligned (mif->ring_data, num_rings - 1, CLIB_CACHE_LINE_BYTES);
+  vec_foreach (rd, mif->ring_data)
+  {
+    rd->last_head = 0;
+  }
+
+  mif->flags &= ~MEMIF_IF_FLAG_CONNECTING;
+  mif->flags |= MEMIF_IF_FLAG_CONNECTED;
+  vnet_hw_interface_set_flags (vnm, mif->hw_if_index,
+			       VNET_HW_INTERFACE_FLAG_LINK_UP);
+}
+
+static void
+memif_disconnect (vlib_main_t * vm, memif_if_t * mif)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+
+  mif->flags &= ~(MEMIF_IF_FLAG_CONNECTED | MEMIF_IF_FLAG_CONNECTING);
+  if (mif->hw_if_index != ~0)
+    vnet_hw_interface_set_flags (vnm, mif->hw_if_index, 0);
+
+  if (mif->interrupt_line.index != ~0)
+    {
+      unix_file_del (&unix_main,
+		     unix_main.file_pool + mif->interrupt_line.index);
+      mif->interrupt_line.index = ~0;
+      mif->interrupt_line.fd = -1;	/* closed in unix_file_del */
+    }
+  if (mif->connection.index != ~0)
+    {
+      unix_file_del (&unix_main, unix_main.file_pool + mif->connection.index);
+      mif->connection.index = ~0;
+      mif->connection.fd = -1;	/* closed in unix_file_del */
+    }
+
+  // TODO: properly munmap + close memif-owned shared memory segments
+  vec_free (mif->regions);
+}
+
+static clib_error_t *
+memif_process_connect_req (memif_pending_conn_t * pending_conn,
+			   memif_msg_t * req, struct ucred *slave_cr,
+			   int shm_fd, int int_fd)
+{
+  memif_main_t *mm = &memif_main;
+  vlib_main_t *vm = vlib_get_main ();
+  int fd = pending_conn->connection.fd;
+  unix_file_t *uf = 0;
+  memif_if_t *mif = 0;
+  memif_msg_t resp = { 0 };
+  unix_file_t template = { 0 };
+  void *shm;
+  uword *p;
+  u8 retval = 0;
+  static clib_error_t *error = 0;
+
+  if (shm_fd == -1)
+    {
+      DEBUG_LOG
+	("Connection request is missing shared memory file descriptor");
+      retval = 1;
+      goto response;
+    }
+
+  if (int_fd == -1)
+    {
+      DEBUG_LOG
+	("Connection request is missing interrupt line file descriptor");
+      retval = 2;
+      goto response;
+    }
+
+  if (slave_cr == NULL)
+    {
+      DEBUG_LOG ("Connection request is missing slave credentials");
+      retval = 3;
+      goto response;
+    }
+
+  p = mhash_get (&mm->if_index_by_key, &req->key);
+  if (!p)
+    {
+      DEBUG_LOG
+	("Connection request with unmatched key (0x%" PRIx64 ")", req->key);
+      retval = 4;
+      goto response;
+    }
+
+  mif = vec_elt_at_index (mm->interfaces, *p);
+  if (mif->listener_index != pending_conn->listener_index)
+    {
+      DEBUG_LOG
+	("Connection request with non-matching listener (%d vs. %d)",
+	 pending_conn->listener_index, mif->listener_index);
+      retval = 5;
+      goto response;
+    }
+
+  if (mif->flags & MEMIF_IF_FLAG_IS_SLAVE)
+    {
+      DEBUG_LOG ("Memif slave does not accept connection requests");
+      retval = 6;
+      goto response;
+    }
+
+  if (mif->connection.fd != -1)
+    {
+      DEBUG_LOG
+	("Memif with key 0x%" PRIx64 " is already connected", mif->key);
+      retval = 7;
+      goto response;
+    }
+
+  if ((mif->flags & MEMIF_IF_FLAG_ADMIN_UP) == 0)
+    {
+      /* just silently decline the request */
+      retval = 8;
+      goto response;
+    }
+
+  if (req->shared_mem_size < sizeof (memif_shm_t))
+    {
+      DEBUG_LOG
+	("Unexpectedly small shared memory segment received from slave.");
+      retval = 9;
+      goto response;
+    }
+
+  if ((shm =
+       mmap (NULL, req->shared_mem_size, PROT_READ | PROT_WRITE, MAP_SHARED,
+	     shm_fd, 0)) == MAP_FAILED)
+    {
+      DEBUG_UNIX_LOG
+	("Failed to map shared memory segment received from slave memif");
+      error = clib_error_return_unix (0, "mmap fd %d", shm_fd);
+      retval = 10;
+      goto response;
+    }
+
+  if (((memif_shm_t *) shm)->cookie != 0xdeadbeef)
+    {
+      DEBUG_LOG
+	("Possibly corrupted shared memory segment received from slave memif");
+      munmap (shm, req->shared_mem_size);
+      retval = 11;
+      goto response;
+    }
+
+  mif->log2_ring_size = req->log2_ring_size;
+  mif->num_s2m_rings = req->num_s2m_rings;
+  mif->num_m2s_rings = req->num_m2s_rings;
+  mif->buffer_size = req->buffer_size;
+  mif->remote_pid = slave_cr->pid;
+  mif->remote_uid = slave_cr->uid;
+  vec_add1 (mif->regions, shm);
+
+  /* register interrupt line */
+  mif->interrupt_line.fd = int_fd;
+  template.read_function = memif_int_fd_read_ready;
+  template.file_descriptor = int_fd;
+  template.private_data = mif->if_index;
+  mif->interrupt_line.index = unix_file_add (&unix_main, &template);
+
+  /* change context for future messages */
+  uf = vec_elt_at_index (unix_main.file_pool, pending_conn->connection.index);
+  uf->private_data = mif->if_index << 1;
+  mif->connection = pending_conn->connection;
+  pool_put (mm->pending_conns, pending_conn);
+
+  memif_connect (vm, mif);
+
+response:
+  resp.version = MEMIF_VERSION;
+  resp.type = MEMIF_MSG_TYPE_CONNECT_RESP;
+  resp.retval = retval;
+  send (fd, &resp, sizeof (resp), 0);
+  return error;
+}
+
+static clib_error_t *
+memif_process_connect_resp (memif_if_t * mif, memif_msg_t * resp)
+{
+  vlib_main_t *vm = vlib_get_main ();
+
+  if ((mif->flags & MEMIF_IF_FLAG_IS_SLAVE) == 0)
+    {
+      DEBUG_LOG ("Memif master does not accept connection responses");
+      return 0;
+    }
+
+  if ((mif->flags & MEMIF_IF_FLAG_CONNECTING) == 0)
+    {
+      DEBUG_LOG ("Unexpected connection response");
+      return 0;
+    }
+
+  if (resp->retval == 0)
+    memif_connect (vm, mif);
+  else
+    memif_disconnect (vm, mif);
+
+  return 0;
+}
+
+static clib_error_t *
+memif_conn_fd_read_ready (unix_file_t * uf)
+{
+  memif_main_t *mm = &memif_main;
+  vlib_main_t *vm = vlib_get_main ();
+  memif_if_t *mif = 0;
+  memif_pending_conn_t *pending_conn = 0;
+  int fd_array[2] = { -1, -1 };
+  char ctl[CMSG_SPACE (sizeof (fd_array)) +
+	   CMSG_SPACE (sizeof (struct ucred))] = { 0 };
+  struct msghdr mh = { 0 };
+  struct iovec iov[1];
+  struct ucred *cr = 0;
+  memif_msg_t msg = { 0 };
+  struct cmsghdr *cmsg;
+  ssize_t size;
+  static clib_error_t *error = 0;
+
+  iov[0].iov_base = (void *) &msg;
+  iov[0].iov_len = sizeof (memif_msg_t);
+  mh.msg_iov = iov;
+  mh.msg_iovlen = 1;
+  mh.msg_control = ctl;
+  mh.msg_controllen = sizeof (ctl);
+
+  /* grab the appropriate context */
+  if (uf->private_data & 1)
+    pending_conn = vec_elt_at_index (mm->pending_conns,
+				     uf->private_data >> 1);
+  else
+    mif = vec_elt_at_index (mm->interfaces, uf->private_data >> 1);
+
+  /* receive the incoming message */
+  size = recvmsg (uf->file_descriptor, &mh, 0);
+  if (size != sizeof (memif_msg_t))
+    {
+      if (size != 0)
+	{
+	  DEBUG_UNIX_LOG ("Malformed message received on fd %d",
+			  uf->file_descriptor);
+	  error = clib_error_return_unix (0, "recvmsg fd %d",
+					  uf->file_descriptor);
+	}
+      goto disconnect;
+    }
+
+  /* check version of the sender's memif plugin */
+  if (msg.version != MEMIF_VERSION)
+    {
+      DEBUG_LOG ("Memif version mismatch");
+      goto disconnect;
+    }
+
+  /* process the message based on its type */
+  switch (msg.type)
+    {
+    case MEMIF_MSG_TYPE_CONNECT_REQ:
+      if (pending_conn == 0)
+	{
+	  DEBUG_LOG ("Received unexpected connection request");
+	  return 0;
+	}
+
+      /* Read anciliary data */
+      cmsg = CMSG_FIRSTHDR (&mh);
+      while (cmsg)
+	{
+	  if (cmsg->cmsg_level == SOL_SOCKET
+	      && cmsg->cmsg_type == SCM_CREDENTIALS)
+	    {
+	      cr = (struct ucred *) CMSG_DATA (cmsg);
+	    }
+	  else if (cmsg->cmsg_level == SOL_SOCKET
+		   && cmsg->cmsg_type == SCM_RIGHTS)
+	    {
+	      clib_memcpy (fd_array, CMSG_DATA (cmsg), sizeof (fd_array));
+	    }
+	  cmsg = CMSG_NXTHDR (&mh, cmsg);
+	}
+
+      return memif_process_connect_req (pending_conn, &msg, cr,
+					fd_array[0], fd_array[1]);
+
+    case MEMIF_MSG_TYPE_CONNECT_RESP:
+      if (mif == 0)
+	{
+	  DEBUG_LOG ("Received unexpected connection response");
+	  return 0;
+	}
+      return memif_process_connect_resp (mif, &msg);
+
+    case MEMIF_MSG_TYPE_DISCONNECT:
+      goto disconnect;
+
+    default:
+      DEBUG_LOG ("Received unknown message type");
+      goto disconnect;
+    }
+
+  return 0;
+
+disconnect:
+  if (pending_conn)
+    memif_remove_pending_conn (pending_conn);
+  else
+    memif_disconnect (vm, mif);
+  return error;
+}
+
+static clib_error_t *
+memif_int_fd_read_ready (unix_file_t * uf)
+{
+  memif_main_t *mm = &memif_main;
+  vlib_main_t *vm = vlib_get_main ();
+  memif_if_t *mif = vec_elt_at_index (mm->interfaces, uf->private_data);
+  u8 b;
+  ssize_t size;
+
+  size = read (uf->file_descriptor, &b, sizeof (b));
+  if (0 == size)
+    {
+      /* interrupt line was disconnected */
+      unix_file_del (&unix_main,
+		     unix_main.file_pool + mif->interrupt_line.index);
+      mif->interrupt_line.index = ~0;
+      mif->interrupt_line.fd = -1;
+    }
+  vlib_node_set_interrupt_pending (vm, memif_input_node.index);
+  return 0;
+}
+
+static clib_error_t *
+memif_conn_fd_accept_ready (unix_file_t * uf)
+{
+  memif_main_t *mm = &memif_main;
+  memif_listener_t *listener = 0;
+  memif_pending_conn_t *pending_conn = 0;
+  int addr_len;
+  struct sockaddr_un client;
+  int conn_fd;
+  unix_file_t template = { 0 };
+
+  listener = pool_elt_at_index (mm->listeners, uf->private_data);
+
+  addr_len = sizeof (client);
+  conn_fd = accept (uf->file_descriptor,
+		    (struct sockaddr *) &client, (socklen_t *) & addr_len);
+
+  if (conn_fd < 0)
+    return clib_error_return_unix (0, "accept fd %d", uf->file_descriptor);
+
+  pool_get (mm->pending_conns, pending_conn);
+  pending_conn->index = pending_conn - mm->pending_conns;
+  pending_conn->listener_index = listener->index;
+  pending_conn->connection.fd = conn_fd;
+
+  template.read_function = memif_conn_fd_read_ready;
+  template.file_descriptor = conn_fd;
+  template.private_data = (pending_conn->index << 1) | 1;
+  pending_conn->connection.index = unix_file_add (&unix_main, &template);
+
+  return 0;
+}
+
+static void
+memif_connect_master (vlib_main_t * vm, memif_if_t * mif)
+{
+  memif_msg_t msg;
+  struct msghdr mh = { 0 };
+  struct iovec iov[1];
+  struct cmsghdr *cmsg;
+  int mfd = -1;
+  int rv;
+  int fd_array[2] = { -1, -1 };
+  char ctl[CMSG_SPACE (sizeof (fd_array))];
+  memif_ring_t *ring = NULL;
+  int i, j;
+  void *shm = 0;
+  u64 buffer_offset;
+  unix_file_t template = { 0 };
+
+  msg.version = MEMIF_VERSION;
+  msg.type = MEMIF_MSG_TYPE_CONNECT_REQ;
+  msg.key = mif->key;
+  msg.log2_ring_size = mif->log2_ring_size;
+  msg.num_s2m_rings = mif->num_s2m_rings;
+  msg.num_m2s_rings = mif->num_m2s_rings;
+  msg.buffer_size = mif->buffer_size;
+
+  buffer_offset = sizeof (memif_shm_t) +
+    (mif->num_s2m_rings + mif->num_m2s_rings) *
+    (sizeof (memif_ring_t) +
+     sizeof (memif_desc_t) * (1 << mif->log2_ring_size));
+
+  msg.shared_mem_size = buffer_offset +
+    mif->buffer_size * (1 << mif->log2_ring_size) * (mif->num_s2m_rings +
+						     mif->num_m2s_rings);
+
+  if ((mfd = memfd_create ("shared mem", MFD_ALLOW_SEALING)) == -1)
+    {
+      DEBUG_LOG ("Failed to create anonymous file");
+      goto error;
+    }
+
+  if ((fcntl (mfd, F_ADD_SEALS, F_SEAL_SHRINK)) == -1)
+    {
+      DEBUG_UNIX_LOG ("Failed to seal an anonymous file off from truncating");
+      goto error;
+    }
+
+  if ((ftruncate (mfd, msg.shared_mem_size)) == -1)
+    {
+      DEBUG_UNIX_LOG ("Failed to extend the size of an anonymous file");
+      goto error;
+    }
+
+  if ((shm = mmap (NULL, msg.shared_mem_size, PROT_READ | PROT_WRITE,
+		   MAP_SHARED, mfd, 0)) == MAP_FAILED)
+    {
+      DEBUG_UNIX_LOG ("Failed to map anonymous file into memory");
+      goto error;
+    }
+
+  vec_add1 (mif->regions, shm);
+  ((memif_shm_t *) mif->regions[0])->cookie = 0xdeadbeef;
+
+  for (i = 0; i < mif->num_s2m_rings; i++)
+    {
+      ring = memif_get_ring (mif, MEMIF_RING_S2M, i);
+      ring->head = ring->tail = 0;
+      for (j = 0; j < (1 << mif->log2_ring_size); j++)
+	{
+	  u16 slot = i * (1 << mif->log2_ring_size) + j;
+	  ring->desc[j].region = 0;
+	  ring->desc[j].offset = buffer_offset + (slot * mif->buffer_size);
+	  ring->desc[j].buffer_length = mif->buffer_size;
+	}
+    }
+  for (i = 0; i < mif->num_m2s_rings; i++)
+    {
+      ring = memif_get_ring (mif, MEMIF_RING_M2S, i);
+      ring->head = ring->tail = 0;
+      for (j = 0; j < (1 << mif->log2_ring_size); j++)
+	{
+	  u16 slot =
+	    (i + mif->num_s2m_rings) * (1 << mif->log2_ring_size) + j;
+	  ring->desc[j].region = 0;
+	  ring->desc[j].offset = buffer_offset + (slot * mif->buffer_size);
+	  ring->desc[j].buffer_length = mif->buffer_size;
+	}
+    }
+
+  iov[0].iov_base = (void *) &msg;
+  iov[0].iov_len = sizeof (memif_msg_t);
+  mh.msg_iov = iov;
+  mh.msg_iovlen = 1;
+
+  /* create interrupt socket */
+  if (socketpair (AF_UNIX, SOCK_STREAM, 0, fd_array) < 0)
+    {
+      DEBUG_UNIX_LOG ("Failed to create a pair of connected sockets");
+      goto error;
+    }
+
+  mif->interrupt_line.fd = fd_array[0];
+  template.read_function = memif_int_fd_read_ready;
+  template.file_descriptor = mif->interrupt_line.fd;
+  template.private_data = mif->if_index;
+  mif->interrupt_line.index = unix_file_add (&unix_main, &template);
+
+  memset (&ctl, 0, sizeof (ctl));
+  mh.msg_control = ctl;
+  mh.msg_controllen = sizeof (ctl);
+  cmsg = CMSG_FIRSTHDR (&mh);
+  cmsg->cmsg_len = CMSG_LEN (sizeof (fd_array));
+  cmsg->cmsg_level = SOL_SOCKET;
+  cmsg->cmsg_type = SCM_RIGHTS;
+  fd_array[0] = mfd;
+  clib_memcpy (CMSG_DATA (cmsg), fd_array, sizeof (fd_array));
+
+  mif->flags |= MEMIF_IF_FLAG_CONNECTING;
+  rv = sendmsg (mif->connection.fd, &mh, 0);
+  if (rv < 0)
+    {
+      DEBUG_UNIX_LOG ("Failed to send memif connection request");
+      goto error;
+    }
+
+  /* No need to keep the descriptor open,
+   * mmap creates an extra reference to the underlying file */
+  close (mfd);
+  mfd = -1;
+  /* This FD is given to peer, so we can close it */
+  close (fd_array[1]);
+  fd_array[1] = -1;
+  return;
+
+error:
+  if (mfd > -1)
+    close (mfd);
+  if (fd_array[1] > -1)
+    close (fd_array[1]);
+  memif_disconnect (vm, mif);
+}
+
+static uword
+memif_process (vlib_main_t * vm, vlib_node_runtime_t * rt, vlib_frame_t * f)
+{
+  memif_main_t *mm = &memif_main;
+  memif_if_t *mif;
+  struct sockaddr_un sun;
+  int sockfd;
+  uword *event_data = 0, event_type;
+  unix_file_t template = { 0 };
+  u8 enabled = 0;
+  f64 start_time, last_run_duration = 0, now;
+
+  sockfd = socket (AF_UNIX, SOCK_STREAM, 0);
+  sun.sun_family = AF_UNIX;
+  template.read_function = memif_conn_fd_read_ready;
+
+  while (1)
+    {
+      if (enabled)
+	vlib_process_wait_for_event_or_clock (vm,
+					      (f64) 3 - last_run_duration);
+      else
+	vlib_process_wait_for_event (vm);
+
+      event_type = vlib_process_get_events (vm, &event_data);
+      vec_reset_length (event_data);
+
+      switch (event_type)
+	{
+	case ~0:
+	  break;
+	case MEMIF_PROCESS_EVENT_START:
+	  enabled = 1;
+	  break;
+	case MEMIF_PROCESS_EVENT_STOP:
+	  enabled = 0;
+	  continue;
+	default:
+	  ASSERT (0);
+	}
+
+      last_run_duration = start_time = vlib_time_now (vm);
+      /* *INDENT-OFF* */
+      pool_foreach (mif, mm->interfaces,
+        ({
+	  /* Allow no more than 10us without a pause */
+	  now = vlib_time_now (vm);
+	  if (now > start_time + 10e-6)
+	    {
+	      vlib_process_suspend (vm, 100e-6);	/* suspend for 100 us */
+	      start_time = vlib_time_now (vm);
+	    }
+
+	  if ((mif->flags & MEMIF_IF_FLAG_ADMIN_UP) == 0)
+	    continue;
+
+	  if (mif->flags & MEMIF_IF_FLAG_CONNECTING)
+	    continue;
+
+	  if (mif->flags & MEMIF_IF_FLAG_CONNECTED)
+	    continue;
+
+	  if (mif->flags & MEMIF_IF_FLAG_IS_SLAVE)
+	    {
+	      strncpy (sun.sun_path, (char *) mif->socket_filename,
+		       sizeof (sun.sun_path) - 1);
+
+	      if (connect
+		  (sockfd, (struct sockaddr *) &sun,
+		   sizeof (struct sockaddr_un)) == 0)
+	        {
+		  mif->connection.fd = sockfd;
+		  template.file_descriptor = sockfd;
+		  template.private_data = mif->if_index << 1;
+		  mif->connection.index = unix_file_add (&unix_main, &template);
+		  memif_connect_master (vm, mif);
+
+		  /* grab another fd */
+		  sockfd = socket (AF_UNIX, SOCK_STREAM, 0);
+		  if (sockfd < 0)
+		    {
+		      DEBUG_UNIX_LOG ("socket AF_UNIX");
+		      return 0;
+		    }
+	        }
+	    }
+        }));
+      /* *INDENT-ON* */
+      last_run_duration = vlib_time_now (vm) - last_run_duration;
+    }
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (memif_process_node,static) = {
+  .function = memif_process,
+  .type = VLIB_NODE_TYPE_PROCESS,
+  .name = "memif-process",
+};
+/* *INDENT-ON* */
+
+static void
+memif_close_if (memif_main_t * mm, memif_if_t * mif)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  memif_listener_t *listener = 0;
+  memif_pending_conn_t *pending_conn = 0;
+
+  memif_disconnect (vm, mif);
+
+  if (mif->listener_index != (uword) ~ 0)
+    {
+      listener = pool_elt_at_index (mm->listeners, mif->listener_index);
+      if (--listener->usage_counter == 0)
+	{
+	  /* not used anymore -> remove the socket and pending connections */
+
+	  /* *INDENT-OFF* */
+	  pool_foreach (pending_conn, mm->pending_conns,
+	    ({
+	       if (pending_conn->listener_index == mif->listener_index)
+	         {
+		   memif_remove_pending_conn (pending_conn);
+	         }
+	     }));
+          /* *INDENT-ON* */
+
+	  unix_file_del (&unix_main,
+			 unix_main.file_pool + listener->socket.index);
+	  pool_put (mm->listeners, listener);
+	  unlink ((char *) mif->socket_filename);
+	}
+    }
+
+  if (mif->lockp != 0)
+    {
+      clib_mem_free ((void *) mif->lockp);
+      mif->lockp = 0;
+    }
+
+  mhash_unset (&mm->if_index_by_key, &mif->key, &mif->if_index);
+  vec_free (mif->socket_filename);
+  vec_free (mif->ring_data);
+
+  memset (mif, 0, sizeof (*mif));
+  pool_put (mm->interfaces, mif);
+}
+
+int
+memif_worker_thread_enable ()
+{
+  /* if worker threads are enabled, switch to polling mode */
+  foreach_vlib_main ((
+		       {
+		       vlib_node_set_state (this_vlib_main,
+					    memif_input_node.index,
+					    VLIB_NODE_STATE_POLLING);
+		       }));
+
+  return 0;
+}
+
+int
+memif_worker_thread_disable ()
+{
+  foreach_vlib_main ((
+		       {
+		       vlib_node_set_state (this_vlib_main,
+					    memif_input_node.index,
+					    VLIB_NODE_STATE_INTERRUPT);
+		       }));
+
+  return 0;
+}
+
+int
+memif_create_if (vlib_main_t * vm, memif_create_if_args_t * args)
+{
+  memif_main_t *mm = &memif_main;
+  vlib_thread_main_t *tm = vlib_get_thread_main ();
+  vnet_main_t *vnm = vnet_get_main ();
+  memif_if_t *mif = 0;
+  vnet_sw_interface_t *sw;
+  clib_error_t *error = 0;
+  int ret = 0;
+  uword *p;
+
+  p = mhash_get (&mm->if_index_by_key, &args->key);
+  if (p)
+    return VNET_API_ERROR_SUBIF_ALREADY_EXISTS;
+
+  pool_get (mm->interfaces, mif);
+  memset (mif, 0, sizeof (*mif));
+  mif->key = args->key;
+  mif->if_index = mif - mm->interfaces;
+  mif->sw_if_index = mif->hw_if_index = mif->per_interface_next_index = ~0;
+  mif->listener_index = ~0;
+  mif->connection.index = mif->interrupt_line.index = ~0;
+  mif->connection.fd = mif->interrupt_line.fd = -1;
+
+  if (tm->n_vlib_mains > 1)
+    {
+      mif->lockp = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES,
+					   CLIB_CACHE_LINE_BYTES);
+      memset ((void *) mif->lockp, 0, CLIB_CACHE_LINE_BYTES);
+    }
+
+  if (!args->hw_addr_set)
+    {
+      f64 now = vlib_time_now (vm);
+      u32 rnd;
+      rnd = (u32) (now * 1e6);
+      rnd = random_u32 (&rnd);
+
+      memcpy (args->hw_addr + 2, &rnd, sizeof (rnd));
+      args->hw_addr[0] = 2;
+      args->hw_addr[1] = 0xfe;
+    }
+
+  error = ethernet_register_interface (vnm, memif_device_class.index,
+				       mif->if_index, args->hw_addr,
+				       &mif->hw_if_index,
+				       memif_eth_flag_change);
+
+  if (error)
+    {
+      clib_error_report (error);
+      ret = VNET_API_ERROR_SYSCALL_ERROR_1;
+      goto error;
+    }
+
+  sw = vnet_get_hw_sw_interface (vnm, mif->hw_if_index);
+  mif->sw_if_index = sw->sw_if_index;
+
+  mif->log2_ring_size = args->log2_ring_size;
+  mif->buffer_size = args->buffer_size;
+
+  /* TODO: make configurable */
+  mif->num_s2m_rings = 1;
+  mif->num_m2s_rings = 1;
+
+  mhash_set_mem (&mm->if_index_by_key, &args->key, &mif->if_index, 0);
+
+  if (args->socket_filename != 0)
+    mif->socket_filename = args->socket_filename;
+  else
+    mif->socket_filename = vec_dup (mm->default_socket_filename);
+
+  args->sw_if_index = mif->sw_if_index;
+
+  if (args->is_master)
+    {
+      struct sockaddr_un un = { 0 };
+      struct stat file_stat;
+      int on = 1;
+      memif_listener_t *listener = 0;
+
+      if (stat ((char *) mif->socket_filename, &file_stat) == 0)
+	{
+	  if (!S_ISSOCK (file_stat.st_mode))
+	    {
+	      errno = ENOTSOCK;
+	      ret = VNET_API_ERROR_SYSCALL_ERROR_2;
+	      goto error;
+	    }
+	  /* *INDENT-OFF* */
+	  pool_foreach (listener, mm->listeners,
+	    ({
+	       if (listener->sock_dev == file_stat.st_dev &&
+		   listener->sock_ino == file_stat.st_ino)
+	         {
+		   /* attach memif to the existing listener */
+		   mif->listener_index = listener->index;
+		   ++listener->usage_counter;
+		   goto signal;
+	         }
+	     }));
+          /* *INDENT-ON* */
+	  unlink ((char *) mif->socket_filename);
+	}
+
+      pool_get (mm->listeners, listener);
+      memset (listener, 0, sizeof (*listener));
+      listener->socket.fd = -1;
+      listener->socket.index = ~0;
+      listener->index = listener - mm->listeners;
+      listener->usage_counter = 1;
+
+      if ((listener->socket.fd = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
+	{
+	  ret = VNET_API_ERROR_SYSCALL_ERROR_3;
+	  goto error;
+	}
+
+      un.sun_family = AF_UNIX;
+      strncpy ((char *) un.sun_path, (char *) mif->socket_filename,
+	       sizeof (un.sun_path) - 1);
+
+      if (setsockopt (listener->socket.fd, SOL_SOCKET, SO_PASSCRED,
+		      &on, sizeof (on)) < 0)
+	{
+	  ret = VNET_API_ERROR_SYSCALL_ERROR_4;
+	  goto error;
+	}
+      if (bind (listener->socket.fd, (struct sockaddr *) &un,
+		sizeof (un)) == -1)
+	{
+	  ret = VNET_API_ERROR_SYSCALL_ERROR_5;
+	  goto error;
+	}
+      if (listen (listener->socket.fd, 1) == -1)
+	{
+	  ret = VNET_API_ERROR_SYSCALL_ERROR_6;
+	  goto error;
+	}
+
+      if (stat ((char *) mif->socket_filename, &file_stat) == -1)
+	{
+	  ret = VNET_API_ERROR_SYSCALL_ERROR_7;
+	  goto error;
+	}
+
+      listener->sock_dev = file_stat.st_dev;
+      listener->sock_ino = file_stat.st_ino;
+
+      unix_file_t template = { 0 };
+      template.read_function = memif_conn_fd_accept_ready;
+      template.file_descriptor = listener->socket.fd;
+      template.private_data = listener->index;
+      listener->socket.index = unix_file_add (&unix_main, &template);
+
+      mif->listener_index = listener->index;
+    }
+  else
+    {
+      mif->flags |= MEMIF_IF_FLAG_IS_SLAVE;
+    }
+
+#if 0
+  /* use configured or generate random MAC address */
+  if (!args->hw_addr_set &&
+      tm->n_vlib_mains > 1 && pool_elts (mm->interfaces) == 1)
+    memif_worker_thread_enable ();
+#endif
+
+signal:
+  if (pool_elts (mm->interfaces) == 1)
+    {
+      vlib_process_signal_event (vm, memif_process_node.index,
+				 MEMIF_PROCESS_EVENT_START, 0);
+    }
+  return 0;
+
+error:
+  if (mif->hw_if_index != ~0)
+    {
+      ethernet_delete_interface (vnm, mif->hw_if_index);
+      mif->hw_if_index = ~0;
+    }
+  memif_close_if (mm, mif);
+  return ret;
+}
+
+int
+memif_delete_if (vlib_main_t * vm, u64 key)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  memif_main_t *mm = &memif_main;
+  memif_if_t *mif;
+  uword *p;
+
+  p = mhash_get (&mm->if_index_by_key, &key);
+  if (p == NULL)
+    {
+      clib_warning ("Memory interface with key 0x%" PRIx64 " does not exist",
+		    key);
+      return VNET_API_ERROR_SYSCALL_ERROR_1;
+    }
+  mif = pool_elt_at_index (mm->interfaces, p[0]);
+  mif->flags |= MEMIF_IF_FLAG_DELETING;
+
+  /* bring down the interface */
+  vnet_hw_interface_set_flags (vnm, mif->hw_if_index, 0);
+  vnet_sw_interface_set_flags (vnm, mif->sw_if_index, 0);
+
+  /* remove the interface */
+  ethernet_delete_interface (vnm, mif->hw_if_index);
+  mif->hw_if_index = ~0;
+  memif_close_if (mm, mif);
+
+  if (pool_elts (mm->interfaces) == 0)
+    {
+      vlib_process_signal_event (vm, memif_process_node.index,
+				 MEMIF_PROCESS_EVENT_STOP, 0);
+    }
+
+#if 0
+  if (tm->n_vlib_mains > 1 && pool_elts (mm->interfaces) == 0)
+    memif_worker_thread_disable ();
+#endif
+
+  return 0;
+}
+
+static clib_error_t *
+memif_init (vlib_main_t * vm)
+{
+  memif_main_t *mm = &memif_main;
+  vlib_thread_main_t *tm = vlib_get_thread_main ();
+  vlib_thread_registration_t *tr;
+  uword *p;
+
+  memset (mm, 0, sizeof (memif_main_t));
+
+  mm->input_cpu_first_index = 0;
+  mm->input_cpu_count = 1;
+
+  /* initialize binary API */
+  memif_plugin_api_hookup (vm);
+
+  /* find out which cpus will be used for input */
+  p = hash_get_mem (tm->thread_registrations_by_name, "workers");
+  tr = p ? (vlib_thread_registration_t *) p[0] : 0;
+
+  if (tr && tr->count > 0)
+    {
+      mm->input_cpu_first_index = tr->first_index;
+      mm->input_cpu_count = tr->count;
+    }
+
+  mhash_init (&mm->if_index_by_key, sizeof (uword), sizeof (u64));
+
+  vec_validate_aligned (mm->rx_buffers, tm->n_vlib_mains - 1,
+			CLIB_CACHE_LINE_BYTES);
+
+  /* set default socket filename */
+  vec_validate (mm->default_socket_filename,
+		strlen (MEMIF_DEFAULT_SOCKET_FILENAME));
+  strncpy ((char *) mm->default_socket_filename,
+	   MEMIF_DEFAULT_SOCKET_FILENAME,
+	   vec_len (mm->default_socket_filename) - 1);
+
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (memif_init);
+
+/* *INDENT-OFF* */
+VLIB_PLUGIN_REGISTER () = {
+    .version = VPP_BUILD_VER,
+    .description = "Packet Memory Interface (experimetal)",
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */