X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvcl%2Fvppcom.c;h=2ccb2b8670557ec951f574bb7c65cf4dac39786d;hb=4878cbe276ec1131d0cf30ac5df18aa9ba699bc4;hp=1b1a08e4c060eca85d06e483d621b91c232c61d3;hpb=ac1f96d7cdfb845c08400d27ec566b991e32e24b;p=vpp.git

diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 1b1a08e4c06..2ccb2b86705 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -41,12 +41,18 @@
 #undef vl_printfun
 
 #if (CLIB_DEBUG > 0)
-/* Set VPPCOM_DEBUG 2 for connection debug, 3 for read/write debug output */
-#define VPPCOM_DEBUG 1
+/* Set VPPCOM_DEBUG_INIT 2 for connection debug,
+ *                       3 for read/write debug output
+ * or
+ *    export VCL_DEBUG=<#> to set dynamically.
+ */
+#define VPPCOM_DEBUG_INIT 1
 #else
-#define VPPCOM_DEBUG 0
+#define VPPCOM_DEBUG_INIT 0
 #endif
 
+#define VPPCOM_DEBUG vcm->debug
+
 /*
  * VPPCOM Private definitions and functions.
  */
@@ -60,14 +66,18 @@ typedef enum
 
 typedef enum
 {
-  STATE_START,
-  STATE_CONNECT,
-  STATE_LISTEN,
-  STATE_ACCEPT,
-  STATE_DISCONNECT,
-  STATE_FAILED
+  STATE_START = 0x01,
+  STATE_CONNECT = 0x02,
+  STATE_LISTEN = 0x04,
+  STATE_ACCEPT = 0x08,
+  STATE_CLOSE_ON_EMPTY = 0x10,
+  STATE_DISCONNECT = 0x20,
+  STATE_FAILED = 0x40
 } session_state_t;
 
+#define SERVER_STATE_OPEN  (STATE_ACCEPT|STATE_CLOSE_ON_EMPTY)
+#define CLIENT_STATE_OPEN  (STATE_CONNECT|STATE_CLOSE_ON_EMPTY)
+
 typedef struct epoll_event vppcom_epoll_event_t;
 
 typedef struct
@@ -77,6 +87,7 @@ typedef struct
   u32 vep_idx;
   vppcom_epoll_event_t ev;
 #define VEP_DEFAULT_ET_MASK  (EPOLLIN|EPOLLOUT)
+#define VEP_UNSUPPORTED_EVENTS (EPOLLONESHOT|EPOLLEXCLUSIVE)
   u32 et_mask;
 } vppcom_epoll_t;
 
@@ -92,8 +103,10 @@ typedef struct
 
   svm_fifo_t *server_rx_fifo;
   svm_fifo_t *server_tx_fifo;
+  u8 *segment_name;
   u32 sm_seg_index;
-  u64 vpp_session_handle;
+  u32 client_context;
+  u64 vpp_handle;
   unix_shared_memory_queue_t *vpp_event_queue;
 
   /* Socket configuration state */
@@ -127,6 +140,12 @@ typedef struct vppcom_cfg_t_
   u32 tx_fifo_size;
   u32 event_queue_size;
   u32 listen_queue_size;
+  u8 app_proxy_transport_tcp;
+  u8 app_proxy_transport_udp;
+  u8 app_scope_local;
+  u8 app_scope_global;
+  u8 *namespace_id;
+  u64 namespace_secret;
   f64 app_timeout;
   f64 session_timeout;
   f64 accept_timeout;
@@ -135,8 +154,8 @@ typedef struct vppcom_cfg_t_
 typedef struct vppcom_main_t_
 {
   u8 init;
+  u32 debug;
   u32 *client_session_index_fifo;
-  volatile u32 bind_session_index;
   int main_cpu;
 
   /* vpe input queue */
@@ -163,8 +182,6 @@ typedef struct vppcom_main_t_
   /* unique segment name counter */
   u32 unique_segment_index;
 
-  pid_t my_pid;
-
   /* For deadman timers */
   clib_time_t clib_time;
 
@@ -177,7 +194,29 @@ typedef struct vppcom_main_t_
   uword *error_string_by_error_number;
 } vppcom_main_t;
 
-vppcom_main_t vppcom_main = {.my_client_index = ~0 };
+/* NOTE: _vppcom_main is only used until the heap is allocated.
+ *       Do not access it directly -- use vcm which will point to
+ *       the heap allocated copy after init.
+ */
+static vppcom_main_t _vppcom_main = {
+  .debug = VPPCOM_DEBUG_INIT,
+  .my_client_index = ~0
+};
+
+static vppcom_main_t *vcm = &_vppcom_main;
+
+#define VCL_LOCK_AND_GET_SESSION(I, S)                  \
+do {                                                    \
+  clib_spinlock_lock (&vcm->sessions_lockp);            \
+  rv = vppcom_session_at_index (I, S);                  \
+  if (PREDICT_FALSE (rv))                               \
+    {                                                   \
+      clib_spinlock_unlock (&vcm->sessions_lockp);      \
+      clib_warning ("[%s] ERROR: Invalid ##I (%u)!",    \
+                    getpid (), I);                      \
+      goto done;                                        \
+    }                                                   \
+} while (0)
 
 static const char *
 vppcom_app_state_str (app_state_t state)
@@ -233,6 +272,10 @@ vppcom_session_state_str (session_state_t state)
       st = "STATE_ACCEPT";
       break;
 
+    case STATE_CLOSE_ON_EMPTY:
+      st = "STATE_CLOSE_ON_EMPTY";
+      break;
+
     case STATE_DISCONNECT:
       st = "STATE_DISCONNECT";
       break;
@@ -255,32 +298,72 @@ vppcom_session_state_str (session_state_t state)
 static inline int
 vppcom_session_at_index (u32 session_index, session_t * volatile *sess)
 {
-  vppcom_main_t *vcm = &vppcom_main;
-
   /* Assumes that caller has acquired spinlock: vcm->sessions_lockp */
   if (PREDICT_FALSE ((session_index == ~0) ||
 		     pool_is_free_index (vcm->sessions, session_index)))
     {
       clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		    vcm->my_pid, session_index);
+		    getpid (), session_index);
       return VPPCOM_EBADFD;
     }
   *sess = pool_elt_at_index (vcm->sessions, session_index);
   return VPPCOM_OK;
 }
 
+static inline void
+vppcom_session_table_add_listener (u64 listener_handle, u32 value)
+{
+  /* Session and listener handles have different formats. The latter has
+   * the thread index in the upper 32 bits while the former has the session
+   * type. Knowing that, for listeners we just flip the MSB to 1 */
+  listener_handle |= 1ULL << 63;
+  hash_set (vcm->session_index_by_vpp_handles, listener_handle, value);
+}
+
+static inline session_t *
+vppcom_session_table_lookup_listener (u64 listener_handle)
+{
+  uword *p;
+  u64 handle = listener_handle | (1ULL << 63);
+  session_t *session;
+
+  p = hash_get (vcm->session_index_by_vpp_handles, handle);
+  if (!p)
+    {
+      clib_warning ("[%d] couldn't find listen session: unknown vpp "
+		    "listener handle %llx", getpid (), listener_handle);
+      return 0;
+    }
+  if (pool_is_free_index (vcm->sessions, p[0]))
+    {
+      if (VPPCOM_DEBUG > 1)
+	clib_warning ("[%d] invalid listen session, sid (%u)", getpid (),
+		      p[0]);
+      return 0;
+    }
+
+  session = pool_elt_at_index (vcm->sessions, p[0]);
+  ASSERT (session->is_listen);
+  return session;
+}
+
+static inline void
+vppcom_session_table_del_listener (u64 listener_handle)
+{
+  listener_handle |= 1ULL << 63;
+  hash_unset (vcm->session_index_by_vpp_handles, listener_handle);
+}
+
 static int
 vppcom_connect_to_vpp (char *app_name)
 {
   api_main_t *am = &api_main;
-  vppcom_main_t *vcm = &vppcom_main;
 
   if (VPPCOM_DEBUG > 0)
     printf ("\nConnecting to VPP api...");
   if (vl_client_connect_to_vlib ("/vpe-api", app_name, 32) < 0)
     {
-      clib_warning ("[%d] connect to vpp (%s) failed!",
-		    vcm->my_pid, app_name);
+      clib_warning ("[%d] connect to vpp (%s) failed!", getpid (), app_name);
       return VPPCOM_ECONNREFUSED;
     }
 
@@ -296,7 +379,6 @@ vppcom_connect_to_vpp (char *app_name)
 static u8 *
 format_api_error (u8 * s, va_list * args)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   i32 error = va_arg (*args, u32);
   uword *p;
 
@@ -312,8 +394,6 @@ format_api_error (u8 * s, va_list * args)
 static void
 vppcom_init_error_string_table (void)
 {
-  vppcom_main_t *vcm = &vppcom_main;
-
   vcm->error_string_by_error_number = hash_create (0, sizeof (uword));
 
 #define _(n,v,s) hash_set (vcm->error_string_by_error_number, -v, s);
@@ -326,7 +406,6 @@ vppcom_init_error_string_table (void)
 static inline int
 vppcom_wait_for_app_state_change (app_state_t app_state)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   f64 timeout = clib_time_now (&vcm->clib_time) + vcm->cfg.app_timeout;
 
   while (clib_time_now (&vcm->clib_time) < timeout)
@@ -335,7 +414,7 @@ vppcom_wait_for_app_state_change (app_state_t app_state)
 	return VPPCOM_OK;
     }
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] timeout waiting for state %s (%d)", vcm->my_pid,
+    clib_warning ("[%d] timeout waiting for state %s (%d)", getpid (),
 		  vppcom_app_state_str (app_state), app_state);
   return VPPCOM_ETIMEDOUT;
 }
@@ -345,7 +424,6 @@ vppcom_wait_for_session_state_change (u32 session_index,
 				      session_state_t state,
 				      f64 wait_for_time)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   f64 timeout = clib_time_now (&vcm->clib_time) + wait_for_time;
   session_t *volatile session;
   int rv;
@@ -364,20 +442,25 @@ vppcom_wait_for_session_state_change (u32 session_index,
 	  clib_spinlock_unlock (&vcm->sessions_lockp);
 	  return VPPCOM_OK;
 	}
+      if (session->state == STATE_FAILED)
+	{
+	  clib_spinlock_unlock (&vcm->sessions_lockp);
+	  return VPPCOM_ECONNREFUSED;
+	}
+
       clib_spinlock_unlock (&vcm->sessions_lockp);
     }
   while (clib_time_now (&vcm->clib_time) < timeout);
 
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] timeout waiting for state %s (%d)", vcm->my_pid,
-		  vppcom_session_state_str (state), state);
+    clib_warning ("[%d] timeout waiting for state 0x%x (%s)", getpid (),
+		  state, vppcom_session_state_str (state));
   return VPPCOM_ETIMEDOUT;
 }
 
 static inline int
 vppcom_wait_for_client_session_index (f64 wait_for_time)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   f64 timeout = clib_time_now (&vcm->clib_time) + wait_for_time;
 
   do
@@ -391,8 +474,7 @@ vppcom_wait_for_client_session_index (f64 wait_for_time)
     return VPPCOM_EAGAIN;
 
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] timeout waiting for client_session_index",
-		  vcm->my_pid);
+    clib_warning ("[%d] timeout waiting for client_session_index", getpid ());
   return VPPCOM_ETIMEDOUT;
 }
 
@@ -402,7 +484,6 @@ vppcom_wait_for_client_session_index (f64 wait_for_time)
 static void
 vppcom_send_session_enable_disable (u8 is_enable)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   vl_api_session_enable_disable_t *bmp;
   bmp = vl_msg_api_alloc (sizeof (*bmp));
   memset (bmp, 0, sizeof (*bmp));
@@ -417,7 +498,6 @@ vppcom_send_session_enable_disable (u8 is_enable)
 static int
 vppcom_app_session_enable (void)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   int rv;
 
   if (vcm->app_state != STATE_APP_ENABLED)
@@ -428,7 +508,7 @@ vppcom_app_session_enable (void)
 	{
 	  if (VPPCOM_DEBUG > 0)
 	    clib_warning ("[%d] Session enable timed out, rv = %s (%d)",
-			  vcm->my_pid, vppcom_retval_str (rv), rv);
+			  getpid (), vppcom_retval_str (rv), rv);
 	  return rv;
 	}
     }
@@ -439,11 +519,9 @@ static void
   vl_api_session_enable_disable_reply_t_handler
   (vl_api_session_enable_disable_reply_t * mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
-
   if (mp->retval)
     {
-      clib_warning ("[%d] session_enable_disable failed: %U", vcm->my_pid,
+      clib_warning ("[%d] session_enable_disable failed: %U", getpid (),
 		    format_api_error, ntohl (mp->retval));
     }
   else
@@ -453,8 +531,11 @@ static void
 static void
 vppcom_app_send_attach (void)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   vl_api_application_attach_t *bmp;
+  u8 nsid_len = vec_len (vcm->cfg.namespace_id);
+  u8 app_is_proxy = (vcm->cfg.app_proxy_transport_tcp ||
+		     vcm->cfg.app_proxy_transport_udp);
+
   bmp = vl_msg_api_alloc (sizeof (*bmp));
   memset (bmp, 0, sizeof (*bmp));
 
@@ -463,18 +544,28 @@ vppcom_app_send_attach (void)
   bmp->context = htonl (0xfeedface);
   bmp->options[APP_OPTIONS_FLAGS] =
     APP_OPTIONS_FLAGS_ACCEPT_REDIRECT | APP_OPTIONS_FLAGS_ADD_SEGMENT |
-    APP_OPTIONS_FLAGS_USE_LOCAL_SCOPE | APP_OPTIONS_FLAGS_USE_GLOBAL_SCOPE;
+    (vcm->cfg.app_scope_local ? APP_OPTIONS_FLAGS_USE_LOCAL_SCOPE : 0) |
+    (vcm->cfg.app_scope_global ? APP_OPTIONS_FLAGS_USE_GLOBAL_SCOPE : 0) |
+    (app_is_proxy ? APP_OPTIONS_FLAGS_IS_PROXY : 0);
+  bmp->options[APP_OPTIONS_PROXY_TRANSPORT] =
+    (vcm->cfg.app_proxy_transport_tcp ? 1 << TRANSPORT_PROTO_TCP : 0) |
+    (vcm->cfg.app_proxy_transport_udp ? 1 << TRANSPORT_PROTO_UDP : 0);
   bmp->options[SESSION_OPTIONS_SEGMENT_SIZE] = vcm->cfg.segment_size;
   bmp->options[SESSION_OPTIONS_ADD_SEGMENT_SIZE] = vcm->cfg.add_segment_size;
   bmp->options[SESSION_OPTIONS_RX_FIFO_SIZE] = vcm->cfg.rx_fifo_size;
   bmp->options[SESSION_OPTIONS_TX_FIFO_SIZE] = vcm->cfg.tx_fifo_size;
+  if (nsid_len)
+    {
+      bmp->namespace_id_len = nsid_len;
+      clib_memcpy (bmp->namespace_id, vcm->cfg.namespace_id, nsid_len);
+      bmp->options[APP_OPTIONS_NAMESPACE_SECRET] = vcm->cfg.namespace_secret;
+    }
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & bmp);
 }
 
 static int
 vppcom_app_attach (void)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   int rv;
 
   vppcom_app_send_attach ();
@@ -483,7 +574,7 @@ vppcom_app_attach (void)
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("[%d] application attach timed out, rv = %s (%d)",
-		      vcm->my_pid, vppcom_retval_str (rv), rv);
+		      getpid (), vppcom_retval_str (rv), rv);
       return rv;
     }
   return VPPCOM_OK;
@@ -492,7 +583,6 @@ vppcom_app_attach (void)
 static void
 vppcom_app_detach (void)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   vl_api_application_detach_t *bmp;
   bmp = vl_msg_api_alloc (sizeof (*bmp));
   memset (bmp, 0, sizeof (*bmp));
@@ -507,7 +597,6 @@ static void
 vl_api_application_attach_reply_t_handler (vl_api_application_attach_reply_t *
 					   mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   static svm_fifo_segment_create_args_t _a;
   svm_fifo_segment_create_args_t *a = &_a;
   int rv;
@@ -515,14 +604,14 @@ vl_api_application_attach_reply_t_handler (vl_api_application_attach_reply_t *
   memset (a, 0, sizeof (*a));
   if (mp->retval)
     {
-      clib_warning ("[%d] attach failed: %U", vcm->my_pid,
+      clib_warning ("[%d] attach failed: %U", getpid (),
 		    format_api_error, ntohl (mp->retval));
       return;
     }
 
   if (mp->segment_name_length == 0)
     {
-      clib_warning ("[%d] segment_name_length zero", vcm->my_pid);
+      clib_warning ("[%d] segment_name_length zero", getpid ());
       return;
     }
 
@@ -536,7 +625,7 @@ vl_api_application_attach_reply_t_handler (vl_api_application_attach_reply_t *
   vec_reset_length (a->new_segment_indices);
   if (PREDICT_FALSE (rv))
     {
-      clib_warning ("[%d] svm_fifo_segment_attach ('%s') failed", vcm->my_pid,
+      clib_warning ("[%d] svm_fifo_segment_attach ('%s') failed", getpid (),
 		    mp->segment_name);
       return;
     }
@@ -552,10 +641,8 @@ static void
 vl_api_application_detach_reply_t_handler (vl_api_application_detach_reply_t *
 					   mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
-
   if (mp->retval)
-    clib_warning ("[%d] detach failed: %U", vcm->my_pid, format_api_error,
+    clib_warning ("[%d] detach failed: %U", getpid (), format_api_error,
 		  ntohl (mp->retval));
 
   vcm->app_state = STATE_APP_ENABLED;
@@ -565,42 +652,15 @@ static void
 vl_api_disconnect_session_reply_t_handler (vl_api_disconnect_session_reply_t *
 					   mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
-  uword *p;
-
-  p = hash_get (vcm->session_index_by_vpp_handles, mp->handle);
-  if (p)
-    {
-      session_t *session = 0;
-      int rv;
-      clib_spinlock_lock (&vcm->sessions_lockp);
-      rv = vppcom_session_at_index (p[0], &session);
-      if (PREDICT_FALSE (rv))
-	{
-	  if (VPPCOM_DEBUG > 1)
-	    clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-			  vcm->my_pid, p[0]);
-	}
-      hash_unset (vcm->session_index_by_vpp_handles, mp->handle);
-      session->state = STATE_DISCONNECT;
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-    }
-  else
-    {
-      if (VPPCOM_DEBUG > 1)
-	clib_warning ("[%d] couldn't find session key %llx", vcm->my_pid,
-		      mp->handle);
-    }
-
   if (mp->retval)
-    clib_warning ("[%d] disconnect_session failed: %U", vcm->my_pid,
-		  format_api_error, ntohl (mp->retval));
+    clib_warning ("[%d] vpp handle 0x%llx: disconnect session failed: %U",
+		  getpid (), mp->handle, format_api_error,
+		  ntohl (mp->retval));
 }
 
 static void
 vl_api_map_another_segment_t_handler (vl_api_map_another_segment_t * mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   static svm_fifo_segment_create_args_t _a;
   svm_fifo_segment_create_args_t *a = &_a;
   int rv;
@@ -614,60 +674,51 @@ vl_api_map_another_segment_t_handler (vl_api_map_another_segment_t * mp)
   if (PREDICT_FALSE (rv))
     {
       clib_warning ("[%d] svm_fifo_segment_attach ('%s') failed",
-		    vcm->my_pid, mp->segment_name);
+		    getpid (), mp->segment_name);
       return;
     }
   if (VPPCOM_DEBUG > 1)
-    clib_warning ("[%d] mapped new segment '%s' size %d", vcm->my_pid,
+    clib_warning ("[%d] mapped new segment '%s' size %d", getpid (),
 		  mp->segment_name, mp->segment_size);
 }
 
 static void
 vl_api_disconnect_session_t_handler (vl_api_disconnect_session_t * mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
-  session_t *session = 0;
-  vl_api_disconnect_session_reply_t *rmp;
   uword *p;
-  int rv = 0;
 
   p = hash_get (vcm->session_index_by_vpp_handles, mp->handle);
   if (p)
     {
-      int rval;
-      clib_spinlock_lock (&vcm->sessions_lockp);
-      rval = vppcom_session_at_index (p[0], &session);
-      if (PREDICT_FALSE (rval))
-	{
-	  if (VPPCOM_DEBUG > 1)
-	    clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-			  vcm->my_pid, p[0]);
-	}
-      else
-	pool_put (vcm->sessions, session);
+      int rv;
+      session_t *session = 0;
+      u32 session_index = p[0];
+
+      VCL_LOCK_AND_GET_SESSION (session_index, &session);
+      session->state = STATE_CLOSE_ON_EMPTY;
+
+      if (VPPCOM_DEBUG > 1)
+	clib_warning ("[%d] vpp handle 0x%llx, sid %u: "
+		      "setting state to %d (%s)",
+		      getpid (), mp->handle, session_index, session->state,
+		      vppcom_session_state_str (session->state));
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      hash_unset (vcm->session_index_by_vpp_handles, mp->handle);
+      return;
+
+    done:
+      if (VPPCOM_DEBUG > 1)
+	clib_warning ("[%d] vpp handle 0x%llx, sid %u: "
+		      "session lookup failed!",
+		      getpid (), mp->handle, session_index);
     }
   else
-    {
-      clib_warning ("[%d] couldn't find session key %llx", vcm->my_pid,
-		    mp->handle);
-      rv = -11;
-    }
-
-  rmp = vl_msg_api_alloc (sizeof (*rmp));
-  memset (rmp, 0, sizeof (*rmp));
-
-  rmp->_vl_msg_id = ntohs (VL_API_DISCONNECT_SESSION_REPLY);
-  rmp->retval = htonl (rv);
-  rmp->handle = mp->handle;
-  vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & rmp);
+    clib_warning ("[%d] vpp handle 0x%llx: session lookup by "
+		  "handle failed!", getpid (), mp->handle);
 }
 
 static void
 vl_api_reset_session_t_handler (vl_api_reset_session_t * mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session = 0;
   vl_api_reset_session_reply_t *rmp;
   uword *p;
@@ -681,20 +732,32 @@ vl_api_reset_session_t_handler (vl_api_reset_session_t * mp)
       rval = vppcom_session_at_index (p[0], &session);
       if (PREDICT_FALSE (rval))
 	{
-	  if (VPPCOM_DEBUG > 1)
-	    clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-			  vcm->my_pid, p[0]);
+	  rv = VNET_API_ERROR_INVALID_VALUE_2;
+	  clib_warning ("[%d] ERROR: sid %u: session lookup failed! "
+			"returning %d %U",
+			getpid (), p[0], rv, format_api_error, rv);
 	}
       else
-	pool_put (vcm->sessions, session);
+	{
+	  /* TBD: should this disconnect immediately and
+	   * flush the fifos?
+	   */
+	  session->state = STATE_CLOSE_ON_EMPTY;
+
+	  if (VPPCOM_DEBUG > 1)
+	    clib_warning ("[%d] vpp handle 0x%llx, sid %u: "
+			  "state set to %d (%s)!", getpid (),
+			  mp->handle, p[0], session->state,
+			  vppcom_session_state_str (session->state));
+	}
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      hash_unset (vcm->session_index_by_vpp_handles, mp->handle);
     }
   else
     {
-      clib_warning ("[%d] couldn't find session key %llx", vcm->my_pid,
-		    mp->handle);
-      rv = -11;
+      rv = VNET_API_ERROR_INVALID_VALUE;
+      clib_warning ("[%d] ERROR: vpp handle 0x%llx: session lookup "
+		    "failed! returning %d %U",
+		    getpid (), mp->handle, rv, format_api_error, rv);
     }
 
   rmp = vl_msg_api_alloc (sizeof (*rmp));
@@ -708,32 +771,32 @@ vl_api_reset_session_t_handler (vl_api_reset_session_t * mp)
 static void
 vl_api_connect_session_reply_t_handler (vl_api_connect_session_reply_t * mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session;
   u32 session_index;
   svm_fifo_t *rx_fifo, *tx_fifo;
   u8 is_cut_thru = 0;
   int rv;
 
+  session_index = mp->context;
   if (mp->retval)
     {
-      clib_warning ("[%d] connect failed: %U", vcm->my_pid, format_api_error,
+      clib_warning ("[%d] ERROR: sid %u: connect failed! %U",
+		    getpid (), session_index, format_api_error,
 		    ntohl (mp->retval));
       return;
     }
 
-  session_index = mp->context;
   if (VPPCOM_DEBUG > 1)
-    clib_warning ("[%d] session_index = %d 0x%08x", vcm->my_pid,
-		  session_index, session_index);
+    clib_warning ("[%d] sid %u: got a connect reply!",
+		  getpid (), session_index);
 
   clib_spinlock_lock (&vcm->sessions_lockp);
   if (pool_is_free_index (vcm->sessions, session_index))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
       if (VPPCOM_DEBUG > 1)
-	clib_warning ("[%d] invalid session, sid %d is closed!",
-		      vcm->my_pid, session_index);
+	clib_warning ("[%d] sid %d: session lookup failed!",
+		      getpid (), session_index);
       return;
     }
 
@@ -747,15 +810,16 @@ vl_api_connect_session_reply_t_handler (vl_api_connect_session_reply_t * mp)
       memset (a, 0, sizeof (*a));
       a->segment_name = (char *) mp->segment_name;
       if (VPPCOM_DEBUG > 1)
-	clib_warning ("[%d] cut-thru segment: %s", vcm->my_pid,
-		      a->segment_name);
+	clib_warning ("[%d] cut-thru segment: %s\n",
+		      getpid (), a->segment_name);
+
       rv = svm_fifo_segment_attach (a);
       vec_reset_length (a->new_segment_indices);
       if (PREDICT_FALSE (rv))
 	{
 	  clib_spinlock_unlock (&vcm->sessions_lockp);
 	  clib_warning ("[%d] sm_fifo_segment_attach ('%s') failed",
-			vcm->my_pid, a->segment_name);
+			getpid (), a->segment_name);
 	  return;
 	}
     }
@@ -763,9 +827,6 @@ vl_api_connect_session_reply_t_handler (vl_api_connect_session_reply_t * mp)
   /*
    * Setup session
    */
-  if (VPPCOM_DEBUG > 1)
-    clib_warning ("[%d] client sid %d", vcm->my_pid, session_index);
-
   session = pool_elt_at_index (vcm->sessions, session_index);
   session->is_cut_thru = is_cut_thru;
   session->vpp_event_queue = uword_to_pointer (mp->vpp_event_queue_address,
@@ -778,18 +839,31 @@ vl_api_connect_session_reply_t_handler (vl_api_connect_session_reply_t * mp)
 
   session->server_rx_fifo = rx_fifo;
   session->server_tx_fifo = tx_fifo;
-  session->vpp_session_handle = mp->handle;
+  session->vpp_handle = mp->handle;
+  session->lcl_addr.is_ip4 = mp->is_ip4;
+  clib_memcpy (&session->lcl_addr.ip46, mp->lcl_ip,
+	       sizeof (session->peer_addr.ip46));
+  session->lcl_port = mp->lcl_port;
   session->state = STATE_CONNECT;
 
   /* Add it to lookup table */
   hash_set (vcm->session_index_by_vpp_handles, mp->handle, session_index);
+
+  if (VPPCOM_DEBUG > 1)
+    clib_warning ("[%d] client sid %d, vpp handle 0x%llx\n"
+		  "  session_rx_fifo %p, refcnt %d\n"
+		  "  session_tx_fifo %p, refcnt %d",
+		  getpid (), session_index, mp->handle,
+		  session->server_rx_fifo,
+		  session->server_rx_fifo->refcnt,
+		  session->server_tx_fifo, session->server_tx_fifo->refcnt);
+
   clib_spinlock_unlock (&vcm->sessions_lockp);
 }
 
 static void
 vppcom_send_connect_sock (session_t * session, u32 session_index)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   vl_api_connect_sock_t *cmp;
 
   /* Assumes caller as acquired the spinlock: vcm->sessions_lockp */
@@ -800,10 +874,6 @@ vppcom_send_connect_sock (session_t * session, u32 session_index)
   cmp->client_index = vcm->my_client_index;
   cmp->context = session_index;
 
-  if (VPPCOM_DEBUG > 1)
-    clib_warning ("[%d] session_index = %d 0x%08x",
-		  vcm->my_pid, session_index, session_index);
-
   cmp->vrf = session->vrf;
   cmp->is_ip4 = session->peer_addr.is_ip4;
   clib_memcpy (cmp->ip, &session->peer_addr.ip46, sizeof (cmp->ip));
@@ -813,57 +883,76 @@ vppcom_send_connect_sock (session_t * session, u32 session_index)
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & cmp);
 }
 
-static int
-vppcom_send_disconnect (u32 session_index)
+static inline void
+vppcom_send_disconnect_session_reply (u64 vpp_handle, u32 session_index,
+				      int rv)
+{
+  vl_api_disconnect_session_reply_t *rmp;
+
+  if (VPPCOM_DEBUG > 1)
+    clib_warning ("[%d] vpp handle 0x%llx, sid %u: sending disconnect msg",
+		  getpid (), vpp_handle, session_index);
+
+  rmp = vl_msg_api_alloc (sizeof (*rmp));
+  memset (rmp, 0, sizeof (*rmp));
+
+  rmp->_vl_msg_id = ntohs (VL_API_DISCONNECT_SESSION_REPLY);
+  rmp->retval = htonl (rv);
+  rmp->handle = vpp_handle;
+  vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & rmp);
+}
+
+static inline void
+vppcom_send_disconnect_session (u64 vpp_handle, u32 session_index)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   vl_api_disconnect_session_t *dmp;
-  session_t *session = 0;
-  int rv;
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (session_index, &session);
-  if (PREDICT_FALSE (rv))
-    {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 1)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, session_index);
-      return rv;
-    }
+  if (VPPCOM_DEBUG > 1)
+    clib_warning ("[%d] vpp handle 0x%llx, sid %u: sending disconnect msg",
+		  getpid (), vpp_handle, session_index);
 
   dmp = vl_msg_api_alloc (sizeof (*dmp));
   memset (dmp, 0, sizeof (*dmp));
   dmp->_vl_msg_id = ntohs (VL_API_DISCONNECT_SESSION);
   dmp->client_index = vcm->my_client_index;
-  dmp->handle = session->vpp_session_handle;
-  clib_spinlock_unlock (&vcm->sessions_lockp);
+  dmp->handle = vpp_handle;
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & dmp);
-  return VPPCOM_OK;
 }
 
 static void
 vl_api_bind_sock_reply_t_handler (vl_api_bind_sock_reply_t * mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session = 0;
+  u32 session_index = mp->context;
   int rv;
 
   if (mp->retval)
-    clib_warning ("[%d] bind failed: %U", vcm->my_pid, format_api_error,
-		  ntohl (mp->retval));
-
-  ASSERT (vcm->bind_session_index != ~0);
+    {
+      clib_warning ("[%d] ERROR: sid %u: bind failed: %U",
+		    getpid (), session_index, format_api_error,
+		    ntohl (mp->retval));
+      rv = vppcom_session_at_index (session_index, &session);
+      if (rv == VPPCOM_OK)
+	session->state = STATE_FAILED;
+      return;
+    }
 
   clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (vcm->bind_session_index, &session);
+  rv = vppcom_session_at_index (session_index, &session);
   if (rv == VPPCOM_OK)
     {
-      session->vpp_session_handle = mp->handle;
-      hash_set (vcm->session_index_by_vpp_handles, mp->handle,
-		vcm->bind_session_index);
-      session->state = mp->retval ? STATE_FAILED : STATE_LISTEN;
-      vcm->bind_session_index = ~0;
+      session->vpp_handle = mp->handle;
+      session->lcl_addr.is_ip4 = mp->lcl_is_ip4;
+      clib_memcpy (&session->lcl_addr.ip46, mp->lcl_ip,
+		   sizeof (session->peer_addr.ip46));
+      session->lcl_port = mp->lcl_port;
+      vppcom_session_table_add_listener (mp->handle, session_index);
+      session->is_listen = 1;
+      session->state = STATE_LISTEN;
+
+      if (VPPCOM_DEBUG > 1)
+	clib_warning ("[%d] sid %u: bind succeeded! ", getpid (),
+		      mp->context);
     }
   clib_spinlock_unlock (&vcm->sessions_lockp);
 }
@@ -871,22 +960,13 @@ vl_api_bind_sock_reply_t_handler (vl_api_bind_sock_reply_t * mp)
 static void
 vl_api_unbind_sock_reply_t_handler (vl_api_unbind_sock_reply_t * mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
-  session_t *session = 0;
-  int rv;
-
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (vcm->bind_session_index, &session);
-  if (rv == VPPCOM_OK)
-    {
-      if ((VPPCOM_DEBUG > 1) && (mp->retval))
-	clib_warning ("[%d] unbind failed: %U", vcm->my_pid, format_api_error,
-		      ntohl (mp->retval));
+  if (mp->retval)
+    clib_warning ("[%d] ERROR: sid %u: unbind failed: %U",
+		  getpid (), mp->context, format_api_error,
+		  ntohl (mp->retval));
 
-      vcm->bind_session_index = ~0;
-      session->state = STATE_START;
-    }
-  clib_spinlock_unlock (&vcm->sessions_lockp);
+  else if (VPPCOM_DEBUG > 1)
+    clib_warning ("[%d] sid %u: unbind succeeded!", getpid (), mp->context);
 }
 
 u8 *
@@ -972,32 +1052,45 @@ format_ip46_address (u8 * s, va_list * args)
     format (s, "%U", format_ip6_address, &ip46->ip6);
 }
 
+static inline void
+vppcom_send_accept_session_reply (u32 handle, int retval)
+{
+  vl_api_accept_session_reply_t *rmp;
+
+  rmp = vl_msg_api_alloc (sizeof (*rmp));
+  memset (rmp, 0, sizeof (*rmp));
+  rmp->_vl_msg_id = ntohs (VL_API_ACCEPT_SESSION_REPLY);
+  rmp->retval = htonl (retval);
+  rmp->handle = handle;
+  vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & rmp);
+}
+
 static void
 vl_api_accept_session_t_handler (vl_api_accept_session_t * mp)
 {
-  vppcom_main_t *vcm = &vppcom_main;
-  vl_api_accept_session_reply_t *rmp;
   svm_fifo_t *rx_fifo, *tx_fifo;
-  session_t *session;
+  session_t *session, *listen_session;
   u32 session_index;
-  int rv = 0;
 
+  clib_spinlock_lock (&vcm->sessions_lockp);
   if (!clib_fifo_free_elts (vcm->client_session_index_fifo))
     {
-      clib_warning ("[%d] client session queue is full!", vcm->my_pid);
-      rv = VNET_API_ERROR_QUEUE_FULL;
-      goto send_reply;
+      clib_warning ("[%d] client session queue is full!", getpid ());
+      vppcom_send_accept_session_reply (mp->handle,
+					VNET_API_ERROR_QUEUE_FULL);
+      clib_spinlock_unlock (&vcm->sessions_lockp);
+      return;
     }
 
-  if (VPPCOM_DEBUG > 1)
+  listen_session = vppcom_session_table_lookup_listener (mp->listener_handle);
+  if (!listen_session)
     {
-      u8 *ip_str = format (0, "%U", format_ip46_address, &mp->ip, mp->is_ip4);
-      clib_warning ("[%d] accepted session from: %s:%d", vcm->my_pid, ip_str,
-		    clib_net_to_host_u16 (mp->port));
-      vec_free (ip_str);
+      clib_warning ("[%d] ERROR: couldn't find listen session: unknown vpp "
+		    "listener handle %llx", getpid (), mp->listener_handle);
+      clib_spinlock_unlock (&vcm->sessions_lockp);
+      return;
     }
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
   /* Allocate local session and set it up */
   pool_get (vcm->sessions, session);
   memset (session, 0, sizeof (*session));
@@ -1008,6 +1101,7 @@ vl_api_accept_session_t_handler (vl_api_accept_session_t * mp)
   tx_fifo = uword_to_pointer (mp->server_tx_fifo, svm_fifo_t *);
   tx_fifo->client_session_index = session_index;
 
+  session->vpp_handle = mp->handle;
   session->server_rx_fifo = rx_fifo;
   session->server_tx_fifo = tx_fifo;
   session->vpp_event_queue = uword_to_pointer (mp->vpp_event_queue_address,
@@ -1022,20 +1116,54 @@ vl_api_accept_session_t_handler (vl_api_accept_session_t * mp)
 
   /* Add it to lookup table */
   hash_set (vcm->session_index_by_vpp_handles, mp->handle, session_index);
+  session->lcl_port = listen_session->lcl_port;
+  session->lcl_addr = listen_session->lcl_addr;
 
+  /* TBD: move client_session_index_fifo into listener session */
   clib_fifo_add1 (vcm->client_session_index_fifo, session_index);
+
   clib_spinlock_unlock (&vcm->sessions_lockp);
 
-  /*
-   * Send accept reply to vpp
-   */
-send_reply:
+  if (VPPCOM_DEBUG > 1)
+    {
+      u8 *ip_str = format (0, "%U", format_ip46_address, &mp->ip, mp->is_ip4);
+      clib_warning ("[%d] received request to accept session (sid %d) "
+		    "from %s:%d", getpid (), session_index, ip_str,
+		    clib_net_to_host_u16 (mp->port));
+      vec_free (ip_str);
+    }
+}
+
+static void
+vppcom_send_connect_session_reply (session_t * session, int retval)
+{
+  vl_api_connect_session_reply_t *rmp;
+  u32 len;
+  unix_shared_memory_queue_t *client_q;
+
   rmp = vl_msg_api_alloc (sizeof (*rmp));
   memset (rmp, 0, sizeof (*rmp));
-  rmp->_vl_msg_id = ntohs (VL_API_ACCEPT_SESSION_REPLY);
-  rmp->retval = htonl (rv);
-  rmp->handle = mp->handle;
-  vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & rmp);
+
+  rmp->_vl_msg_id = ntohs (VL_API_CONNECT_SESSION_REPLY);
+  rmp->context = session->client_context;
+  rmp->retval = htonl (retval);
+  rmp->handle = session->vpp_handle;
+  rmp->server_rx_fifo = pointer_to_uword (session->server_rx_fifo);
+  rmp->server_tx_fifo = pointer_to_uword (session->server_tx_fifo);
+  rmp->vpp_event_queue_address = pointer_to_uword (session->vpp_event_queue);
+  rmp->segment_size = vcm->cfg.segment_size;
+  len = vec_len (session->segment_name);
+  rmp->segment_name_length = clib_min (len, sizeof (rmp->segment_name));
+  clib_memcpy (rmp->segment_name, session->segment_name,
+	       rmp->segment_name_length - 1);
+  clib_memcpy (rmp->lcl_ip, session->peer_addr.ip46.as_u8,
+	       sizeof (rmp->lcl_ip));
+  rmp->is_ip4 = session->peer_addr.is_ip4;
+  rmp->lcl_port = session->peer_port;
+  client_q = uword_to_pointer (session->client_queue_address,
+			       unix_shared_memory_queue_t *);
+  ASSERT (client_q);
+  vl_msg_api_send_shmem (client_q, (u8 *) & rmp);
 }
 
 /*
@@ -1044,149 +1172,54 @@ send_reply:
 static void
 vl_api_connect_sock_t_handler (vl_api_connect_sock_t * mp)
 {
-  static svm_fifo_segment_create_args_t _a;
-  svm_fifo_segment_create_args_t *a = &_a;
-  vppcom_main_t *vcm = &vppcom_main;
   u32 session_index;
-  svm_fifo_segment_private_t *seg;
-  unix_shared_memory_queue_t *client_q;
-  vl_api_connect_session_reply_t *rmp;
   session_t *session = 0;
-  int rv = 0;
-  svm_fifo_t *rx_fifo;
-  svm_fifo_t *tx_fifo;
-  unix_shared_memory_queue_t *event_q = 0;
 
   clib_spinlock_lock (&vcm->sessions_lockp);
   if (!clib_fifo_free_elts (vcm->client_session_index_fifo))
     {
-      if (VPPCOM_DEBUG > 1)
-	clib_warning ("[%d] client session queue is full!", vcm->my_pid);
-      rv = VNET_API_ERROR_QUEUE_FULL;
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      goto send_reply;
-    }
 
-  /* Create the segment */
-  memset (a, 0, sizeof (*a));
-  a->segment_name = (char *) format ((u8 *) a->segment_name, "%d:segment%d%c",
-				     vcm->my_pid, vcm->unique_segment_index++,
-				     0);
-  a->segment_size = vcm->cfg.segment_size;
-  a->preallocated_fifo_pairs = vcm->cfg.preallocated_fifo_pairs;
-  a->rx_fifo_size = vcm->cfg.rx_fifo_size;
-  a->tx_fifo_size = vcm->cfg.tx_fifo_size;
-
-  rv = svm_fifo_segment_create (a);
-  if (PREDICT_FALSE (rv))
-    {
       if (VPPCOM_DEBUG > 1)
-	clib_warning ("[%d] svm_fifo_segment_create ('%s') failed",
-		      vcm->my_pid, a->segment_name);
-      vec_reset_length (a->new_segment_indices);
-      rv = VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
-      goto send_reply;
-    }
+	clib_warning ("[%d] client session queue is full!", getpid ());
 
-  if (VPPCOM_DEBUG > 1)
-    clib_warning ("[%d] created segment '%s'", vcm->my_pid, a->segment_name);
+      /* TBD: fix handle missing in api msg. */
+      vppcom_send_accept_session_reply (0, VNET_API_ERROR_QUEUE_FULL);
+      return;
+    }
 
   pool_get (vcm->sessions, session);
   memset (session, 0, sizeof (*session));
   session_index = session - vcm->sessions;
 
-  session->sm_seg_index = a->new_segment_indices[0];
-  vec_reset_length (a->new_segment_indices);
-
-  seg = svm_fifo_segment_get_segment (session->sm_seg_index);
-  rx_fifo = session->server_rx_fifo =
-    svm_fifo_segment_alloc_fifo (seg, vcm->cfg.rx_fifo_size,
-				 FIFO_SEGMENT_RX_FREELIST);
-  if (PREDICT_FALSE (!session->server_rx_fifo))
-    {
-      svm_fifo_segment_delete (seg);
-      clib_warning ("[%d] rx fifo alloc failed, size %ld (0x%lx)",
-		    vcm->my_pid, vcm->cfg.rx_fifo_size,
-		    vcm->cfg.rx_fifo_size);
-      rv = VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      goto send_reply;
-    }
-
-  tx_fifo = session->server_tx_fifo =
-    svm_fifo_segment_alloc_fifo (seg, vcm->cfg.tx_fifo_size,
-				 FIFO_SEGMENT_TX_FREELIST);
-  if (PREDICT_FALSE (!session->server_tx_fifo))
-    {
-      svm_fifo_segment_delete (seg);
-      if (VPPCOM_DEBUG > 1)
-	clib_warning ("[%d] tx fifo alloc failed, size %ld (0x%lx)",
-		      vcm->my_pid, vcm->cfg.tx_fifo_size,
-		      vcm->cfg.tx_fifo_size);
-      rv = VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      goto send_reply;
-    }
-
-  session->server_rx_fifo->master_session_index = session_index;
-  session->server_tx_fifo->master_session_index = session_index;
+  session->client_context = mp->context;
+  session->vpp_handle = session_index;
   session->client_queue_address = mp->client_queue_address;
   session->is_cut_thru = 1;
   session->is_server = 1;
-  session->peer_port = mp->port;
+  session->lcl_port = mp->port;
+  session->lcl_addr.is_ip4 = mp->is_ip4;
+  clib_memcpy (&session->lcl_addr.ip46, mp->ip,
+	       sizeof (session->lcl_addr.ip46));
+
+  /* TBD: missing peer info in api msg.
+   */
   session->peer_addr.is_ip4 = mp->is_ip4;
-  clib_memcpy (&session->peer_addr.ip46, mp->ip,
-	       sizeof (session->peer_addr.ip46));
-  {
-    void *oldheap;
-    ssvm_shared_header_t *sh = seg->ssvm.sh;
-
-    ssvm_lock_non_recursive (sh, 1);
-    oldheap = ssvm_push_heap (sh);
-    event_q = session->vpp_event_queue =
-      unix_shared_memory_queue_init (vcm->cfg.event_queue_size,
-				     sizeof (session_fifo_event_t),
-				     vcm->my_pid, 0 /* signal not sent */ );
-    ssvm_pop_heap (oldheap);
-    ssvm_unlock_non_recursive (sh);
-  }
+  ASSERT (session->lcl_addr.is_ip4 == session->peer_addr.is_ip4);
 
   session->state = STATE_ACCEPT;
-  if (VPPCOM_DEBUG > 1)
-    clib_warning ("[%d] Connected cut-thru to client: sid %d",
-		  vcm->my_pid, session_index);
   clib_fifo_add1 (vcm->client_session_index_fifo, session_index);
+  if (VPPCOM_DEBUG > 1)
+    clib_warning ("[%d] sid %u: Got a cut-thru connect request! "
+		  "clib_fifo_elts %u!\n", getpid (), session_index,
+		  clib_fifo_elts (vcm->client_session_index_fifo));
   clib_spinlock_unlock (&vcm->sessions_lockp);
+}
 
-send_reply:
-  rmp = vl_msg_api_alloc (sizeof (*rmp));
-  memset (rmp, 0, sizeof (*rmp));
-
-  rmp->_vl_msg_id = ntohs (VL_API_CONNECT_SESSION_REPLY);
-  rmp->context = mp->context;
-  rmp->retval = htonl (rv);
-  rmp->segment_name_length = vec_len (a->segment_name);
-  clib_memcpy (rmp->segment_name, a->segment_name, vec_len (a->segment_name));
-  vec_reset_length (a->segment_name);
-
-  if (event_q)
-    {
-      rmp->vpp_event_queue_address = pointer_to_uword (event_q);
-      rmp->server_rx_fifo = pointer_to_uword (rx_fifo);
-      rmp->server_tx_fifo = pointer_to_uword (tx_fifo);
-    }
-  client_q =
-    uword_to_pointer (mp->client_queue_address, unix_shared_memory_queue_t *);
-
-  ASSERT (client_q);
-  vl_msg_api_send_shmem (client_q, (u8 *) & rmp);
-}
-
-static void
-vppcom_send_bind_sock (session_t * session)
-{
-  vppcom_main_t *vcm = &vppcom_main;
-  vl_api_bind_sock_t *bmp;
+static void
+vppcom_send_bind_sock (session_t * session, u32 session_index)
+{
+  vl_api_bind_sock_t *bmp;
 
   /* Assumes caller has acquired spinlock: vcm->sessions_lockp */
   session->is_server = 1;
@@ -1195,7 +1228,7 @@ vppcom_send_bind_sock (session_t * session)
 
   bmp->_vl_msg_id = ntohs (VL_API_BIND_SOCK);
   bmp->client_index = vcm->my_client_index;
-  bmp->context = htonl (0xfeedface);
+  bmp->context = session_index;
   bmp->vrf = session->vrf;
   bmp->is_ip4 = session->lcl_addr.is_ip4;
   clib_memcpy (bmp->ip, &session->lcl_addr.ip46, sizeof (bmp->ip));
@@ -1206,103 +1239,156 @@ vppcom_send_bind_sock (session_t * session)
 }
 
 static void
-vppcom_send_unbind_sock (u32 session_index)
+vppcom_send_unbind_sock (u64 vpp_handle)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   vl_api_unbind_sock_t *ump;
-  session_t *session = 0;
-  int rv;
-
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (session_index, &session);
-  if (PREDICT_FALSE (rv))
-    {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, session_index);
-      return;
-    }
 
   ump = vl_msg_api_alloc (sizeof (*ump));
   memset (ump, 0, sizeof (*ump));
 
   ump->_vl_msg_id = ntohs (VL_API_UNBIND_SOCK);
   ump->client_index = vcm->my_client_index;
-  ump->handle = session->vpp_session_handle;
-  clib_spinlock_unlock (&vcm->sessions_lockp);
+  ump->handle = vpp_handle;
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & ump);
 }
 
 static int
-vppcom_session_unbind_cut_thru (session_t * session)
+vppcom_session_unbind (u32 session_index)
 {
-  svm_fifo_segment_main_t *sm = &svm_fifo_segment_main;
-  svm_fifo_segment_private_t *seg;
-  int rv = VPPCOM_OK;
+  session_t *session = 0;
+  int rv;
+  u64 vpp_handle;
+
+  VCL_LOCK_AND_GET_SESSION (session_index, &session);
+
+  vpp_handle = session->vpp_handle;
+  vppcom_session_table_del_listener (vpp_handle);
+  session->vpp_handle = ~0;
+  session->state = STATE_DISCONNECT;
+
+  clib_spinlock_unlock (&vcm->sessions_lockp);
+
+  if (VPPCOM_DEBUG > 1)
+    clib_warning ("[%d] vpp handle 0x%llx, sid %u: "
+		  "sending unbind msg! new state 0x%x (%s)",
+		  getpid (), vpp_handle, session_index,
+		  session->state, vppcom_session_state_str (session->state));
 
-  seg = vec_elt_at_index (sm->segments, session->sm_seg_index);
-  svm_fifo_segment_free_fifo (seg, session->server_rx_fifo,
-			      FIFO_SEGMENT_RX_FREELIST);
-  svm_fifo_segment_free_fifo (seg, session->server_tx_fifo,
-			      FIFO_SEGMENT_TX_FREELIST);
-  svm_fifo_segment_delete (seg);
+  vppcom_send_unbind_sock (vpp_handle);
 
+done:
   return rv;
 }
 
-static int
-vppcom_session_unbind (u32 session_index)
+static inline int
+vppcom_session_disconnect (u32 session_index)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   int rv;
+  session_t *session;
+  u8 is_cut_thru, is_listen, is_server;
+  u64 vpp_handle;
+  session_state_t state;
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  if (PREDICT_FALSE (pool_is_free_index (vcm->sessions, session_index)))
+  VCL_LOCK_AND_GET_SESSION (session_index, &session);
+
+  vpp_handle = session->vpp_handle;
+  is_server = session->is_server;
+  is_listen = session->is_listen;
+  is_cut_thru = session->is_cut_thru;
+  state = session->state;
+  clib_spinlock_unlock (&vcm->sessions_lockp);
+
+  if (VPPCOM_DEBUG > 1)
     {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 1)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_EBADFD;
+      clib_warning ("[%d] vpp handle 0x%llx, sid %u: %s state 0x%x (%s), "
+		    "is_cut_thru %d, is_listen %d",
+		    getpid (), vpp_handle, session_index,
+		    is_server ? "server" : "client",
+		    state, vppcom_session_state_str (state),
+		    is_cut_thru, is_listen);
     }
-  clib_spinlock_unlock (&vcm->sessions_lockp);
 
-  vcm->bind_session_index = session_index;
-  vppcom_send_unbind_sock (session_index);
-  rv = vppcom_wait_for_session_state_change (session_index, STATE_START,
-					     vcm->cfg.session_timeout);
-  if (PREDICT_FALSE (rv))
+  if (PREDICT_FALSE (is_listen))
     {
-      vcm->bind_session_index = ~0;
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] server unbind timed out, rv = %s (%d)",
-		      vcm->my_pid, vppcom_retval_str (rv), rv);
-      return rv;
+      clib_warning ("[%d] ERROR: sid %u: Cannot disconnect a "
+		    "listen socket!", getpid (), session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
-  return VPPCOM_OK;
-}
 
-static int
-vppcom_session_disconnect (u32 session_index)
-{
-  vppcom_main_t *vcm = &vppcom_main;
-  int rv;
+  /* Through the VPP host stack...
+   */
+  else if (!is_cut_thru)
+    {
+      /* The peer has already initiated the close,
+       * so send the disconnect session reply.
+       */
+      if (state & STATE_CLOSE_ON_EMPTY)
+	{
+	  vppcom_send_disconnect_session_reply (vpp_handle,
+						session_index, 0 /* rv */ );
+	  if (VPPCOM_DEBUG > 1)
+	    clib_warning ("[%d] sid %u: sending disconnect REPLY...",
+			  getpid (), session_index);
+	}
 
-  rv = vppcom_send_disconnect (session_index);
-  if (PREDICT_FALSE (rv))
-    return rv;
+      /* Otherwise, send a disconnect session msg...
+       */
+      else
+	{
+	  if (VPPCOM_DEBUG > 1)
+	    clib_warning ("[%d] sid %u: sending disconnect...",
+			  getpid (), session_index, state,
+			  vppcom_session_state_str (state));
 
-  rv = vppcom_wait_for_session_state_change (session_index, STATE_DISCONNECT,
-					     vcm->cfg.session_timeout);
-  if (PREDICT_FALSE (rv))
+	  vppcom_send_disconnect_session (vpp_handle, session_index);
+	}
+    }
+
+  /* Cut-thru connections...
+   *
+   *   server: free fifos and segment allocated during connect/redirect
+   *   client: no cleanup required
+   */
+  else
     {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] client disconnect timed out, rv = %s (%d)",
-		      vcm->my_pid, vppcom_retval_str (rv), rv);
-      return rv;
+      if (is_server)
+	{
+	  svm_fifo_segment_main_t *sm = &svm_fifo_segment_main;
+	  svm_fifo_segment_private_t *seg;
+
+	  VCL_LOCK_AND_GET_SESSION (session_index, &session);
+
+	  if (VPPCOM_DEBUG > 1)
+	    clib_warning ("[%d] sid %d: freeing cut-thru fifos in "
+			  "sm_seg_index %d\n"
+			  "  server_rx_fifo %p, refcnt = %d\n"
+			  "  server_tx_fifo %p, refcnt = %d",
+			  getpid (), session_index, session->sm_seg_index,
+			  session->server_rx_fifo,
+			  session->server_rx_fifo->refcnt,
+			  session->server_tx_fifo,
+			  session->server_tx_fifo->refcnt);
+
+	  seg = vec_elt_at_index (sm->segments, session->sm_seg_index);
+	  svm_fifo_segment_free_fifo (seg, session->server_rx_fifo,
+				      FIFO_SEGMENT_RX_FREELIST);
+	  svm_fifo_segment_free_fifo (seg, session->server_tx_fifo,
+				      FIFO_SEGMENT_TX_FREELIST);
+	  svm_fifo_segment_delete (seg);
+
+	  /* TBD: Send cut-thru disconnect event to client */
+
+	  clib_spinlock_unlock (&vcm->sessions_lockp);
+	}
+      else
+	{
+	  /* TBD: Send cut-thru disconnect event to server */
+	}
     }
-  return VPPCOM_OK;
+
+done:
+  return rv;
 }
 
 #define foreach_sock_msg                                        \
@@ -1355,7 +1441,6 @@ vppcom_cfg_init (vppcom_cfg_t * vcl_cfg)
 static void
 vppcom_cfg_heapsize (char *conf_fname)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   vppcom_cfg_t *vcl_cfg = &vcm->cfg;
   FILE *fp;
   char inbuf[4096];
@@ -1366,6 +1451,8 @@ vppcom_cfg_heapsize (char *conf_fname)
   int i;
   u8 *sizep;
   u32 size;
+  void *vcl_mem;
+  void *heap;
 
   fp = fopen (conf_fname, "r");
   if (fp == NULL)
@@ -1432,7 +1519,7 @@ vppcom_cfg_heapsize (char *conf_fname)
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] parse error '%s %s', "
 			      "using default heapsize %lld (0x%llx)",
-			      vcm->my_pid, argv[i], argv[i + 1],
+			      getpid (), argv[i], argv[i + 1],
 			      vcl_cfg->heapsize, vcl_cfg->heapsize);
 	      goto defaulted;
 	    }
@@ -1446,7 +1533,7 @@ vppcom_cfg_heapsize (char *conf_fname)
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] parse error '%s %s', "
 			      "using default heapsize %lld (0x%llx)",
-			      vcm->my_pid, argv[i], argv[i + 1],
+			      getpid (), argv[i], argv[i + 1],
 			      vcl_cfg->heapsize, vcl_cfg->heapsize);
 	      goto defaulted;
 	    }
@@ -1458,17 +1545,41 @@ defaulted:
     fclose (fp);
   if (argv != NULL)
     free (argv);
-  if (!clib_mem_init (0, vcl_cfg->heapsize))
-    clib_warning ("[%d] vppcom heap allocation failure!", vcm->my_pid);
-  else if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] allocated vppcom heapsize %lld (0x%llx)",
-		  vcm->my_pid, vcl_cfg->heapsize, vcl_cfg->heapsize);
+
+  vcl_mem = mmap (0, vcl_cfg->heapsize, PROT_READ | PROT_WRITE,
+		  MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+  if (vcl_mem == MAP_FAILED)
+    {
+      clib_unix_error ("[%d] ERROR: mmap(0, %lld == 0x%llx, "
+		       "PROT_READ | PROT_WRITE,MAP_SHARED | MAP_ANONYMOUS, "
+		       "-1, 0) failed!",
+		       getpid (), vcl_cfg->heapsize, vcl_cfg->heapsize);
+      return;
+    }
+  heap = clib_mem_init (vcl_mem, vcl_cfg->heapsize);
+  if (!heap)
+    {
+      clib_warning ("[%d] ERROR: clib_mem_init() failed!", getpid ());
+      return;
+    }
+  vcl_mem = clib_mem_alloc (sizeof (_vppcom_main));
+  if (!vcl_mem)
+    {
+      clib_warning ("[%d] ERROR: clib_mem_alloc() failed!", getpid ());
+      return;
+    }
+
+  clib_memcpy (vcl_mem, &_vppcom_main, sizeof (_vppcom_main));
+  vcm = vcl_mem;
+
+  if (VPPCOM_DEBUG > 0)
+    clib_warning ("[%d] allocated VCL heap = %p, size %lld (0x%llx)",
+		  getpid (), heap, vcl_cfg->heapsize, vcl_cfg->heapsize);
 }
 
 static void
 vppcom_cfg_read (char *conf_fname)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   vppcom_cfg_t *vcl_cfg = &vcm->cfg;
   int fd;
   unformat_input_t _input, *input = &_input;
@@ -1483,22 +1594,21 @@ vppcom_cfg_read (char *conf_fname)
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("[%d] open configuration file '%s' failed!",
-		      vcm->my_pid, conf_fname);
+		      getpid (), conf_fname);
       goto file_done;
     }
 
   if (fstat (fd, &s) < 0)
     {
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] failed to stat `%s'", vcm->my_pid, conf_fname);
+	clib_warning ("[%d] failed to stat `%s'", getpid (), conf_fname);
       goto file_done;
     }
 
   if (!(S_ISREG (s.st_mode) || S_ISLNK (s.st_mode)))
     {
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] not a regular file `%s'", vcm->my_pid,
-		      conf_fname);
+	clib_warning ("[%d] not a regular file `%s'", getpid (), conf_fname);
       goto file_done;
     }
 
@@ -1509,7 +1619,7 @@ vppcom_cfg_read (char *conf_fname)
       (void) unformat_user (input, unformat_line_input, line_input);
       unformat_skip_white_space (line_input);
 
-      if (unformat (line_input, "vppcom {"))
+      if (unformat (line_input, "vcl {"))
 	{
 	  vc_cfg_input = 1;
 	  continue;
@@ -1523,7 +1633,7 @@ vppcom_cfg_read (char *conf_fname)
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured heapsize %s, "
 			      "actual heapsize %lld (0x%llx)",
-			      vcm->my_pid, chroot_path, vcl_cfg->heapsize,
+			      getpid (), chroot_path, vcl_cfg->heapsize,
 			      vcl_cfg->heapsize);
 	      vec_free (chroot_path);
 	    }
@@ -1533,34 +1643,34 @@ vppcom_cfg_read (char *conf_fname)
 	      vl_set_memory_root_path ((char *) chroot_path);
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured api-prefix %s",
-			      vcm->my_pid, chroot_path);
+			      getpid (), chroot_path);
 	      chroot_path = 0;	/* Don't vec_free() it! */
 	    }
 	  else if (unformat (line_input, "uid %d", &uid))
 	    {
 	      vl_set_memory_uid (uid);
 	      if (VPPCOM_DEBUG > 0)
-		clib_warning ("[%d] configured uid %d", vcm->my_pid, uid);
+		clib_warning ("[%d] configured uid %d", getpid (), uid);
 	    }
 	  else if (unformat (line_input, "gid %d", &gid))
 	    {
 	      vl_set_memory_gid (gid);
 	      if (VPPCOM_DEBUG > 0)
-		clib_warning ("[%d] configured gid %d", vcm->my_pid, gid);
+		clib_warning ("[%d] configured gid %d", getpid (), gid);
 	    }
-	  else if (unformat (line_input, "segment-baseva 0x%llx",
+	  else if (unformat (line_input, "segment-baseva 0x%lx",
 			     &vcl_cfg->segment_baseva))
 	    {
 	      if (VPPCOM_DEBUG > 0)
-		clib_warning ("[%d] configured segment_baseva 0x%llx",
-			      vcm->my_pid, vcl_cfg->segment_baseva);
+		clib_warning ("[%d] configured segment_baseva 0x%lx",
+			      getpid (), vcl_cfg->segment_baseva);
 	    }
 	  else if (unformat (line_input, "segment-size 0x%lx",
 			     &vcl_cfg->segment_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured segment_size 0x%lx (%ld)",
-			      vcm->my_pid, vcl_cfg->segment_size,
+			      getpid (), vcl_cfg->segment_size,
 			      vcl_cfg->segment_size);
 	    }
 	  else if (unformat (line_input, "segment-size %ld",
@@ -1568,7 +1678,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured segment_size %ld (0x%lx)",
-			      vcm->my_pid, vcl_cfg->segment_size,
+			      getpid (), vcl_cfg->segment_size,
 			      vcl_cfg->segment_size);
 	    }
 	  else if (unformat (line_input, "add-segment-size 0x%lx",
@@ -1577,7 +1687,7 @@ vppcom_cfg_read (char *conf_fname)
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning
 		  ("[%d] configured add_segment_size 0x%lx (%ld)",
-		   vcm->my_pid, vcl_cfg->add_segment_size,
+		   getpid (), vcl_cfg->add_segment_size,
 		   vcl_cfg->add_segment_size);
 	    }
 	  else if (unformat (line_input, "add-segment-size %ld",
@@ -1586,7 +1696,7 @@ vppcom_cfg_read (char *conf_fname)
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning
 		  ("[%d] configured add_segment_size %ld (0x%lx)",
-		   vcm->my_pid, vcl_cfg->add_segment_size,
+		   getpid (), vcl_cfg->add_segment_size,
 		   vcl_cfg->add_segment_size);
 	    }
 	  else if (unformat (line_input, "preallocated-fifo-pairs %d",
@@ -1594,7 +1704,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured preallocated_fifo_pairs "
-			      "%d (0x%x)", vcm->my_pid,
+			      "%d (0x%x)", getpid (),
 			      vcl_cfg->preallocated_fifo_pairs,
 			      vcl_cfg->preallocated_fifo_pairs);
 	    }
@@ -1603,7 +1713,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured rx_fifo_size 0x%lx (%ld)",
-			      vcm->my_pid, vcl_cfg->rx_fifo_size,
+			      getpid (), vcl_cfg->rx_fifo_size,
 			      vcl_cfg->rx_fifo_size);
 	    }
 	  else if (unformat (line_input, "rx-fifo-size %ld",
@@ -1611,7 +1721,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured rx_fifo_size %ld (0x%lx)",
-			      vcm->my_pid, vcl_cfg->rx_fifo_size,
+			      getpid (), vcl_cfg->rx_fifo_size,
 			      vcl_cfg->rx_fifo_size);
 	    }
 	  else if (unformat (line_input, "tx-fifo-size 0x%lx",
@@ -1619,7 +1729,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured tx_fifo_size 0x%lx (%ld)",
-			      vcm->my_pid, vcl_cfg->tx_fifo_size,
+			      getpid (), vcl_cfg->tx_fifo_size,
 			      vcl_cfg->tx_fifo_size);
 	    }
 	  else if (unformat (line_input, "tx-fifo-size %ld",
@@ -1627,7 +1737,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured tx_fifo_size %ld (0x%lx)",
-			      vcm->my_pid, vcl_cfg->tx_fifo_size,
+			      getpid (), vcl_cfg->tx_fifo_size,
 			      vcl_cfg->tx_fifo_size);
 	    }
 	  else if (unformat (line_input, "event-queue-size 0x%lx",
@@ -1635,7 +1745,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured event_queue_size 0x%lx (%ld)",
-			      vcm->my_pid, vcl_cfg->event_queue_size,
+			      getpid (), vcl_cfg->event_queue_size,
 			      vcl_cfg->event_queue_size);
 	    }
 	  else if (unformat (line_input, "event-queue-size %ld",
@@ -1643,7 +1753,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured event_queue_size %ld (0x%lx)",
-			      vcm->my_pid, vcl_cfg->event_queue_size,
+			      getpid (), vcl_cfg->event_queue_size,
 			      vcl_cfg->event_queue_size);
 	    }
 	  else if (unformat (line_input, "listen-queue-size 0x%lx",
@@ -1651,7 +1761,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured listen_queue_size 0x%lx (%ld)",
-			      vcm->my_pid, vcl_cfg->listen_queue_size,
+			      getpid (), vcl_cfg->listen_queue_size,
 			      vcl_cfg->listen_queue_size);
 	    }
 	  else if (unformat (line_input, "listen-queue-size %ld",
@@ -1659,7 +1769,7 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured listen_queue_size %ld (0x%lx)",
-			      vcm->my_pid, vcl_cfg->listen_queue_size,
+			      getpid (), vcl_cfg->listen_queue_size,
 			      vcl_cfg->listen_queue_size);
 	    }
 	  else if (unformat (line_input, "app-timeout %f",
@@ -1667,28 +1777,84 @@ vppcom_cfg_read (char *conf_fname)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured app_timeout %f",
-			      vcm->my_pid, vcl_cfg->app_timeout);
+			      getpid (), vcl_cfg->app_timeout);
 	    }
 	  else if (unformat (line_input, "session-timeout %f",
 			     &vcl_cfg->session_timeout))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured session_timeout %f",
-			      vcm->my_pid, vcl_cfg->session_timeout);
+			      getpid (), vcl_cfg->session_timeout);
 	    }
 	  else if (unformat (line_input, "accept-timeout %f",
 			     &vcl_cfg->accept_timeout))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] configured accept_timeout %f",
-			      vcm->my_pid, vcl_cfg->accept_timeout);
+			      getpid (), vcl_cfg->accept_timeout);
+	    }
+	  else if (unformat (line_input, "app-proxy-transport-tcp"))
+	    {
+	      vcl_cfg->app_proxy_transport_tcp = 1;
+	      if (VPPCOM_DEBUG > 0)
+		clib_warning ("[%d] configured app_proxy_transport_tcp (%d)",
+			      getpid (), vcl_cfg->app_proxy_transport_tcp);
+	    }
+	  else if (unformat (line_input, "app-proxy-transport-udp"))
+	    {
+	      vcl_cfg->app_proxy_transport_udp = 1;
+	      if (VPPCOM_DEBUG > 0)
+		clib_warning ("[%d] configured app_proxy_transport_udp (%d)",
+			      getpid (), vcl_cfg->app_proxy_transport_udp);
+	    }
+	  else if (unformat (line_input, "app-scope-local"))
+	    {
+	      vcl_cfg->app_scope_local = 1;
+	      if (VPPCOM_DEBUG > 0)
+		clib_warning ("[%d] configured app_scope_local (%d)",
+			      getpid (), vcl_cfg->app_scope_local);
+	    }
+	  else if (unformat (line_input, "app-scope-global"))
+	    {
+	      vcl_cfg->app_scope_global = 1;
+	      if (VPPCOM_DEBUG > 0)
+		clib_warning ("[%d] configured app_scope_global (%d)",
+			      getpid (), vcl_cfg->app_scope_global);
+	    }
+	  else if (unformat (line_input, "namespace-secret %lu",
+			     &vcl_cfg->namespace_secret))
+	    {
+	      if (VPPCOM_DEBUG > 0)
+		clib_warning
+		  ("[%d] configured namespace_secret %lu (0x%lx)",
+		   getpid (), vcl_cfg->namespace_secret,
+		   vcl_cfg->namespace_secret);
+	    }
+	  else if (unformat (line_input, "namespace-id %v",
+			     &vcl_cfg->namespace_id))
+	    {
+	      vl_api_application_attach_t *mp;
+	      u32 max_nsid_vec_len = sizeof (mp->namespace_id) - 1;
+	      u32 nsid_vec_len = vec_len (vcl_cfg->namespace_id);
+	      if (nsid_vec_len > max_nsid_vec_len)
+		{
+		  _vec_len (vcl_cfg->namespace_id) = max_nsid_vec_len;
+		  if (VPPCOM_DEBUG > 0)
+		    clib_warning ("[%d] configured namespace_id is too long,"
+				  " truncated to %d characters!", getpid (),
+				  max_nsid_vec_len);
+		}
+
+	      if (VPPCOM_DEBUG > 0)
+		clib_warning ("[%d] configured namespace_id %v",
+			      getpid (), vcl_cfg->namespace_id);
 	    }
 	  else if (unformat (line_input, "}"))
 	    {
 	      vc_cfg_input = 0;
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("[%d] completed parsing vppcom config!",
-			      vcm->my_pid);
+			      getpid ());
 	      goto input_done;
 	    }
 	  else
@@ -1696,7 +1862,7 @@ vppcom_cfg_read (char *conf_fname)
 	      if (line_input->buffer[line_input->index] != '#')
 		{
 		  clib_warning ("[%d] Unknown vppcom config option: '%s'",
-				vcm->my_pid, (char *)
+				getpid (), (char *)
 				&line_input->buffer[line_input->index]);
 		}
 	    }
@@ -1717,7 +1883,6 @@ file_done:
 int
 vppcom_app_create (char *app_name)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   vppcom_cfg_t *vcl_cfg = &vcm->cfg;
   u8 *heap;
   mheap_t *h;
@@ -1726,23 +1891,103 @@ vppcom_app_create (char *app_name)
   if (!vcm->init)
     {
       char *conf_fname;
+      char *env_var_str;
 
       vcm->init = 1;
-      vcm->my_pid = getpid ();
-      clib_fifo_validate (vcm->client_session_index_fifo,
-			  vcm->cfg.listen_queue_size);
       vppcom_cfg_init (vcl_cfg);
-      conf_fname = getenv (VPPCOM_CONF_ENV);
+      env_var_str = getenv (VPPCOM_ENV_DEBUG);
+      if (env_var_str)
+	{
+	  u32 tmp;
+	  if (sscanf (env_var_str, "%u", &tmp) != 1)
+	    clib_warning ("[%d] Invalid debug level specified in "
+			  "the environment variable "
+			  VPPCOM_ENV_DEBUG
+			  " (%s)!\n", getpid (), env_var_str);
+	  else
+	    {
+	      vcm->debug = tmp;
+	      clib_warning ("[%d] configured debug level (%u) from "
+			    VPPCOM_ENV_DEBUG "!", getpid (), vcm->debug);
+	    }
+	}
+      conf_fname = getenv (VPPCOM_ENV_CONF);
       if (!conf_fname)
 	{
 	  conf_fname = VPPCOM_CONF_DEFAULT;
 	  if (VPPCOM_DEBUG > 0)
-	    clib_warning ("[%d] getenv '%s' failed!", vcm->my_pid,
-			  VPPCOM_CONF_ENV);
+	    clib_warning ("[%d] getenv '%s' failed!", getpid (),
+			  VPPCOM_ENV_CONF);
 	}
       vppcom_cfg_heapsize (conf_fname);
+      clib_fifo_validate (vcm->client_session_index_fifo,
+			  vcm->cfg.listen_queue_size);
       vppcom_cfg_read (conf_fname);
-      vcm->bind_session_index = ~0;
+      env_var_str = getenv (VPPCOM_ENV_APP_NAMESPACE_ID);
+      if (env_var_str)
+	{
+	  u32 ns_id_vec_len = strlen (env_var_str);
+
+	  vec_reset_length (vcm->cfg.namespace_id);
+	  vec_validate (vcm->cfg.namespace_id, ns_id_vec_len - 1);
+	  clib_memcpy (vcm->cfg.namespace_id, env_var_str, ns_id_vec_len);
+
+	  if (VPPCOM_DEBUG > 0)
+	    clib_warning ("[%d] configured namespace_id (%v) from "
+			  VPPCOM_ENV_APP_NAMESPACE_ID "!", getpid (),
+			  vcm->cfg.namespace_id);
+	}
+      env_var_str = getenv (VPPCOM_ENV_APP_NAMESPACE_SECRET);
+      if (env_var_str)
+	{
+	  u64 tmp;
+	  if (sscanf (env_var_str, "%lu", &tmp) != 1)
+	    clib_warning ("[%d] Invalid namespace secret specified in "
+			  "the environment variable "
+			  VPPCOM_ENV_APP_NAMESPACE_SECRET
+			  " (%s)!\n", getpid (), env_var_str);
+	  else
+	    {
+	      vcm->cfg.namespace_secret = tmp;
+	      if (VPPCOM_DEBUG > 0)
+		clib_warning ("[%d] configured namespace secret (%lu) from "
+			      VPPCOM_ENV_APP_NAMESPACE_ID "!", getpid (),
+			      vcm->cfg.namespace_secret);
+	    }
+	}
+      if (getenv (VPPCOM_ENV_APP_PROXY_TRANSPORT_TCP))
+	{
+	  vcm->cfg.app_proxy_transport_tcp = 1;
+	  if (VPPCOM_DEBUG > 0)
+	    clib_warning ("[%d] configured app_proxy_transport_tcp (%u) from "
+			  VPPCOM_ENV_APP_PROXY_TRANSPORT_TCP "!", getpid (),
+			  vcm->cfg.app_proxy_transport_tcp);
+	}
+      if (getenv (VPPCOM_ENV_APP_PROXY_TRANSPORT_UDP))
+	{
+	  vcm->cfg.app_proxy_transport_udp = 1;
+	  if (VPPCOM_DEBUG > 0)
+	    clib_warning ("[%d] configured app_proxy_transport_udp (%u) from "
+			  VPPCOM_ENV_APP_PROXY_TRANSPORT_UDP "!", getpid (),
+			  vcm->cfg.app_proxy_transport_udp);
+	}
+      if (getenv (VPPCOM_ENV_APP_SCOPE_LOCAL))
+	{
+	  vcm->cfg.app_scope_local = 1;
+	  if (VPPCOM_DEBUG > 0)
+	    clib_warning ("[%d] configured app_scope_local (%u) from "
+			  VPPCOM_ENV_APP_SCOPE_LOCAL "!", getpid (),
+			  vcm->cfg.app_scope_local);
+	}
+      if (getenv (VPPCOM_ENV_APP_SCOPE_GLOBAL))
+	{
+	  vcm->cfg.app_scope_global = 1;
+	  if (VPPCOM_DEBUG > 0)
+	    clib_warning ("[%d] configured app_scope_global (%u) from "
+			  VPPCOM_ENV_APP_SCOPE_GLOBAL "!", getpid (),
+			  vcm->cfg.app_scope_global);
+	}
+
       vcm->main_cpu = os_get_thread_index ();
       heap = clib_mem_get_per_cpu_heap ();
       h = mheap_header (heap);
@@ -1766,36 +2011,36 @@ vppcom_app_create (char *app_name)
       rv = vppcom_connect_to_vpp (app_name);
       if (rv)
 	{
-	  clib_warning ("[%d] couldn't connect to VPP.", vcm->my_pid);
+	  clib_warning ("[%d] ERROR: couldn't connect to VPP!", getpid ());
 	  return rv;
 	}
 
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] sending session enable", vcm->my_pid);
+	clib_warning ("[%d] sending session enable", getpid ());
 
       rv = vppcom_app_session_enable ();
       if (rv)
 	{
-	  clib_warning ("[%d] vppcom_app_session_enable() failed!",
-			vcm->my_pid);
+	  clib_warning ("[%d] ERROR: vppcom_app_session_enable() failed!",
+			getpid ());
 	  return rv;
 	}
 
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] sending app attach", vcm->my_pid);
+	clib_warning ("[%d] sending app attach", getpid ());
 
       rv = vppcom_app_attach ();
       if (rv)
 	{
-	  clib_warning ("[%d] vppcom_app_attach() failed!", vcm->my_pid);
+	  clib_warning ("[%d] ERROR: vppcom_app_attach() failed!", getpid ());
 	  return rv;
 	}
-    }
 
-  if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] app_name '%s', my_client_index %d (0x%x)",
-		  vcm->my_pid, app_name, vcm->my_client_index,
-		  vcm->my_client_index);
+      if (VPPCOM_DEBUG > 0)
+	clib_warning ("[%d] app_name '%s', my_client_index %d (0x%x)",
+		      getpid (), app_name, vcm->my_client_index,
+		      vcm->my_client_index);
+    }
 
   return VPPCOM_OK;
 }
@@ -1803,7 +2048,6 @@ vppcom_app_create (char *app_name)
 void
 vppcom_app_destroy (void)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   int rv;
 
   if (vcm->my_client_index == ~0)
@@ -1811,7 +2055,7 @@ vppcom_app_destroy (void)
 
   if (VPPCOM_DEBUG > 0)
     clib_warning ("[%d] detaching from VPP, my_client_index %d (0x%x)",
-		  vcm->my_pid, vcm->my_client_index, vcm->my_client_index);
+		  getpid (), vcm->my_client_index, vcm->my_client_index);
 
   vppcom_app_detach ();
   rv = vppcom_wait_for_app_state_change (STATE_APP_ENABLED);
@@ -1819,7 +2063,7 @@ vppcom_app_destroy (void)
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("[%d] application detach timed out, rv = %s (%d)",
-		      vcm->my_pid, vppcom_retval_str (rv), rv);
+		      getpid (), vppcom_retval_str (rv), rv);
     }
   vl_client_disconnect_from_vlib ();
   vcm->my_client_index = ~0;
@@ -1829,7 +2073,6 @@ vppcom_app_destroy (void)
 int
 vppcom_session_create (u32 vrf, u8 proto, u8 is_nonblocking)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session;
   u32 session_index;
 
@@ -1842,10 +2085,11 @@ vppcom_session_create (u32 vrf, u8 proto, u8 is_nonblocking)
   session->proto = proto;
   session->state = STATE_START;
   session->is_nonblocking = is_nonblocking ? 1 : 0;
+  session->vpp_handle = ~0;
   clib_spinlock_unlock (&vcm->sessions_lockp);
 
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] sid %d", vcm->my_pid, session_index);
+    clib_warning ("[%d] sid %u", getpid (), session_index);
 
   return (int) session_index;
 }
@@ -1853,106 +2097,95 @@ vppcom_session_create (u32 vrf, u8 proto, u8 is_nonblocking)
 int
 vppcom_session_close (uint32_t session_index)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session = 0;
   int rv;
+  u8 is_listen;
+  u8 is_vep;
+  u8 is_vep_session;
+  u32 next_sid;
+  u32 vep_idx;
+  uword *p;
+  session_state_t state;
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (session_index, &session);
-  if (PREDICT_FALSE (rv))
-    {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, session_index);
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      goto done;
-    }
+  VCL_LOCK_AND_GET_SESSION (session_index, &session);
+  is_listen = session->is_listen;
+  is_vep = session->is_vep;
+  is_vep_session = session->is_vep_session;
+  next_sid = session->vep.next_sid;
+  vep_idx = session->vep.vep_idx;
+  state = session->state;
   clib_spinlock_unlock (&vcm->sessions_lockp);
 
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] sid %d", vcm->my_pid, session_index);
+    clib_warning ("[%d] sid %d: closing session...", getpid (),
+		  session_index);
 
-  if (session->is_vep)
+  if (is_vep)
     {
-      u32 next_sid;
-      for (next_sid = session->vep.next_sid; next_sid != ~0;
-	   next_sid = session->vep.next_sid)
+      while (next_sid != ~0)
 	{
 	  rv = vppcom_epoll_ctl (session_index, EPOLL_CTL_DEL, next_sid, 0);
 	  if ((VPPCOM_DEBUG > 0) && (rv < 0))
-	    clib_warning ("[%d] EPOLL_CTL_DEL vep_idx %u, sid %u failed, "
-			  "rv = %s (%d)", session_index, next_sid,
-			  vcm->my_pid, session_index,
-			  vppcom_retval_str (rv), rv);
+	    clib_warning ("[%d] sid %u: EPOLL_CTL_DEL vep_idx %u failed, "
+			  "rv = %d (%s)", getpid (), next_sid, vep_idx,
+			  rv, vppcom_retval_str (rv));
 
-	  clib_spinlock_lock (&vcm->sessions_lockp);
-	  rv = vppcom_session_at_index (session_index, &session);
-	  if (PREDICT_FALSE (rv))
-	    {
-	      if (VPPCOM_DEBUG > 0)
-		clib_warning
-		  ("[%d] invalid session, sid (%u) has been closed!",
-		   vcm->my_pid, session_index);
-	      clib_spinlock_unlock (&vcm->sessions_lockp);
-	      goto done;
-	    }
+	  VCL_LOCK_AND_GET_SESSION (session_index, &session);
+	  next_sid = session->vep.next_sid;
 	  clib_spinlock_unlock (&vcm->sessions_lockp);
 	}
     }
   else
     {
-      if (session->is_vep_session)
+      if (is_vep_session)
 	{
-	  u32 vep_idx = session->vep.vep_idx;
 	  rv = vppcom_epoll_ctl (vep_idx, EPOLL_CTL_DEL, session_index, 0);
 	  if ((VPPCOM_DEBUG > 0) && (rv < 0))
-	    clib_warning ("[%d] EPOLL_CTL_DEL vep_idx %u, sid %u failed, "
-			  "rv = %s (%d)", vep_idx, session_index,
-			  vcm->my_pid, session_index,
-			  vppcom_retval_str (rv), rv);
+	    clib_warning ("[%d] sid %u: EPOLL_CTL_DEL vep_idx %u failed!  "
+			  "rv = %d (%s)", getpid (), session_index, vep_idx,
+			  rv, vppcom_retval_str (rv));
+	}
 
-	  clib_spinlock_lock (&vcm->sessions_lockp);
-	  rv = vppcom_session_at_index (session_index, &session);
-	  if (PREDICT_FALSE (rv))
+      if (is_listen)
+	{
+	  if (state == STATE_LISTEN)
 	    {
-	      if (VPPCOM_DEBUG > 0)
-		clib_warning
-		  ("[%d] invalid session, sid (%u) has been closed!",
-		   vcm->my_pid, session_index);
-	      clib_spinlock_unlock (&vcm->sessions_lockp);
-	      goto done;
+	      rv = vppcom_session_unbind (session_index);
+	      if (PREDICT_FALSE (rv < 0))
+		{
+		  if (VPPCOM_DEBUG > 0)
+		    clib_warning ("[%d] sid %u: listener unbind failed!  "
+				  "rv = %d (%s)",
+				  getpid (), session_index, rv,
+				  vppcom_retval_str (rv));
+		}
 	    }
-	  clib_spinlock_unlock (&vcm->sessions_lockp);
 	}
 
-      if (session->is_cut_thru && session->is_server &&
-	  (session->state == STATE_ACCEPT))
-	{
-	  rv = vppcom_session_unbind_cut_thru (session);
-	  if ((VPPCOM_DEBUG > 0) && (rv < 0))
-	    clib_warning ("[%d] unbind cut-thru (session %d) failed, "
-			  "rv = %s (%d)",
-			  vcm->my_pid, session_index,
-			  vppcom_retval_str (rv), rv);
-	}
-      else if (session->is_server && session->is_listen)
-	{
-	  rv = vppcom_session_unbind (session_index);
-	  if ((VPPCOM_DEBUG > 0) && (rv < 0))
-	    clib_warning ("[%d] unbind (session %d) failed, rv = %s (%d)",
-			  vcm->my_pid, session_index,
-			  vppcom_retval_str (rv), rv);
-	}
-      else if (session->state == STATE_CONNECT)
+      else if (state & (CLIENT_STATE_OPEN | SERVER_STATE_OPEN))
 	{
 	  rv = vppcom_session_disconnect (session_index);
-	  if ((VPPCOM_DEBUG > 0) && (rv < 0))
-	    clib_warning ("[%d] disconnect (session %d) failed, rv = %s (%d)",
-			  vcm->my_pid, session_index,
-			  vppcom_retval_str (rv), rv);
+	  if (PREDICT_FALSE (rv < 0))
+	    clib_warning ("[%d] ERROR: sid %u: session disconnect failed!  "
+			  "rv %d (%s)", getpid (), session_index, rv,
+			  vppcom_retval_str (rv));
 	}
     }
+
+  VCL_LOCK_AND_GET_SESSION (session_index, &session);
+
+  if (session->vpp_handle != ~0)
+    {
+      p = hash_get (vcm->session_index_by_vpp_handles, session->vpp_handle);
+      if (p)
+	hash_unset (vcm->session_index_by_vpp_handles, session->vpp_handle);
+    }
   pool_put_index (vcm->sessions, session_index);
+  clib_spinlock_unlock (&vcm->sessions_lockp);
+
+  if (VPPCOM_DEBUG > 0)
+    clib_warning ("[%d] sid %u: session removed.", getpid (), session_index);
+
 done:
   return rv;
 }
@@ -1960,31 +2193,21 @@ done:
 int
 vppcom_session_bind (uint32_t session_index, vppcom_endpt_t * ep)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session = 0;
   int rv;
 
   if (!ep || !ep->ip)
     return VPPCOM_EINVAL;
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (session_index, &session);
-  if (PREDICT_FALSE (rv))
-    {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, session_index);
-      return rv;
-    }
+  VCL_LOCK_AND_GET_SESSION (session_index, &session);
 
   if (session->is_vep)
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) is an epoll session!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_EBADFD;
+      clib_warning ("[%d] ERROR: sid %u: cannot bind to an epoll session!",
+		    getpid (), session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
 
   session->vrf = ep->vrf;
@@ -1993,126 +2216,103 @@ vppcom_session_bind (uint32_t session_index, vppcom_endpt_t * ep)
   session->lcl_port = ep->port;
 
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] sid %d, bound to lcl address %U lcl port %u",
-		  vcm->my_pid, session_index, format_ip46_address,
+    clib_warning ("[%d] sid %u: bound to local address %U "
+		  "port %u, proto %s",
+		  getpid (), session_index, format_ip46_address,
 		  &session->lcl_addr.ip46, session->lcl_addr.is_ip4,
-		  clib_net_to_host_u16 (session->lcl_port));
+		  clib_net_to_host_u16 (session->lcl_port),
+		  session->proto ? "UDP" : "TCP");
 
   clib_spinlock_unlock (&vcm->sessions_lockp);
-  return VPPCOM_OK;
+done:
+  return rv;
 }
 
 int
 vppcom_session_listen (uint32_t listen_session_index, uint32_t q_len)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *listen_session = 0;
   int rv;
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (listen_session_index, &listen_session);
-  if (PREDICT_FALSE (rv))
+  VCL_LOCK_AND_GET_SESSION (listen_session_index, &listen_session);
+
+  if (listen_session->is_vep)
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, listen_session_index);
-      return rv;
+      clib_warning ("[%d] ERROR: sid %u: cannot listen on an "
+		    "epoll session!", getpid (), listen_session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
 
-  if (listen_session->is_vep)
+  if (listen_session->is_listen)
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) is an epoll session!",
-		      vcm->my_pid, listen_session_index);
-      return VPPCOM_EBADFD;
+	clib_warning ("[%d] sid %u: already in listen state!",
+		      getpid (), listen_session_index);
+      rv = VPPCOM_OK;
+      goto done;
     }
 
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] sid %d", vcm->my_pid, listen_session_index);
+    clib_warning ("[%d] sid %u: sending bind request...",
+		  getpid (), listen_session_index);
 
-  ASSERT (vcm->bind_session_index == ~0);
-  vcm->bind_session_index = listen_session_index;
-  vppcom_send_bind_sock (listen_session);
+  vppcom_send_bind_sock (listen_session, listen_session_index);
   clib_spinlock_unlock (&vcm->sessions_lockp);
   rv =
     vppcom_wait_for_session_state_change (listen_session_index, STATE_LISTEN,
 					  vcm->cfg.session_timeout);
   if (PREDICT_FALSE (rv))
     {
-      vcm->bind_session_index = ~0;
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] server listen timed out, rv = %d (%d)",
-		      vcm->my_pid, vppcom_retval_str (rv), rv);
+	clib_warning ("[%d] sid %u: bind failed! returning %d (%d)",
+		      getpid (), vppcom_retval_str (rv), rv);
       return rv;
     }
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (listen_session_index, &listen_session);
-  if (PREDICT_FALSE (rv))
-    {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, listen_session_index);
-      return rv;
-    }
-  listen_session->is_listen = 1;
+  VCL_LOCK_AND_GET_SESSION (listen_session_index, &listen_session);
   clib_fifo_validate (vcm->client_session_index_fifo, q_len);
   clib_spinlock_unlock (&vcm->sessions_lockp);
-
-  return VPPCOM_OK;
+done:
+  return rv;
 }
 
 int
 vppcom_session_accept (uint32_t listen_session_index, vppcom_endpt_t * ep,
-		       double wait_for_time)
+		       uint32_t flags, double wait_for_time)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *listen_session = 0;
   session_t *client_session = 0;
-  u32 client_session_index;
+  u32 client_session_index = ~0;
   int rv;
   f64 wait_for;
+  char *cut_thru_str;
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (listen_session_index, &listen_session);
-  if (PREDICT_FALSE (rv))
-    {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, listen_session_index);
-      return rv;
-    }
+  VCL_LOCK_AND_GET_SESSION (listen_session_index, &listen_session);
 
   if (listen_session->is_vep)
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) is an epoll session!",
-		      vcm->my_pid, listen_session_index);
-      return VPPCOM_EBADFD;
+      clib_warning ("[%d] ERROR: sid %u: cannot accept on an "
+		    "epoll session!", getpid (), listen_session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
 
   if (listen_session->state != STATE_LISTEN)
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] session not in listen state, state = %s",
-		      vcm->my_pid,
-		      vppcom_session_state_str (listen_session->state));
-      return VPPCOM_EBADFD;
+      clib_warning ("[%d] ERROR: sid %u: not in listen state! "
+		    "state 0x%x (%s)", getpid (), listen_session->state,
+		    vppcom_session_state_str (listen_session->state));
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
-  wait_for = listen_session->is_nonblocking ? 0 :
-    (wait_for_time < 0) ? vcm->cfg.accept_timeout : wait_for_time;
+  wait_for = ((listen_session->is_nonblocking) ? 0 :
+	      (wait_for_time < 0) ? vcm->cfg.accept_timeout : wait_for_time);
 
-  if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] sid %d: %s (%d)", vcm->my_pid,
-		  listen_session_index,
-		  vppcom_session_state_str (listen_session->state),
-		  listen_session->state);
   clib_spinlock_unlock (&vcm->sessions_lockp);
 
   while (1)
@@ -2121,11 +2321,12 @@ vppcom_session_accept (uint32_t listen_session_index, vppcom_endpt_t * ep,
       if (rv)
 	{
 	  if ((VPPCOM_DEBUG > 0))
-	    clib_warning ("[%d] sid %d, accept timed out, rv = %s (%d)",
-			  vcm->my_pid, listen_session_index,
-			  vppcom_retval_str (rv), rv);
+	    clib_warning ("[%d] sid %u: accept failed! "
+			  "returning = %d (%s)",
+			  getpid (), listen_session_index,
+			  rv, vppcom_retval_str (rv));
 	  if ((wait_for == 0) || (wait_for_time > 0))
-	    return rv;
+	    goto done;
 	}
       else
 	break;
@@ -2138,13 +2339,11 @@ vppcom_session_accept (uint32_t listen_session_index, vppcom_endpt_t * ep,
   ASSERT (client_session->peer_addr.is_ip4 ==
 	  listen_session->lcl_addr.is_ip4);
 
+  client_session->is_nonblocking = (flags & O_NONBLOCK) ? 1 : 0;
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] Got a request: client sid %d", vcm->my_pid,
-		  client_session_index);
-
-  // Copy the lcl information from the listening session to the client session
-  //  client_session->lcl_port = listen_session->lcl_port;
-  //  client_session->lcl_addr = listen_session->lcl_addr;
+    clib_warning ("[%d] sid %u: Got a client request! flags %d, "
+		  "is_nonblocking %u", getpid (), client_session_index,
+		  flags, client_session->is_nonblocking);
 
   ep->vrf = client_session->vrf;
   ep->is_cut_thru = client_session->is_cut_thru;
@@ -2156,50 +2355,170 @@ vppcom_session_accept (uint32_t listen_session_index, vppcom_endpt_t * ep,
   else
     clib_memcpy (ep->ip, &client_session->peer_addr.ip46.ip6,
 		 sizeof (ip6_address_t));
+
+  if (client_session->is_server && client_session->is_cut_thru)
+    {
+      static svm_fifo_segment_create_args_t _a;
+      svm_fifo_segment_create_args_t *a = &_a;
+      svm_fifo_segment_private_t *seg;
+
+      cut_thru_str = " cut-thru ";
+
+      /* Create the segment */
+      memset (a, 0, sizeof (*a));
+      a->segment_name = (char *)
+	format ((u8 *) a->segment_name, "%d:segment%d%c",
+		getpid (), vcm->unique_segment_index++, 0);
+      a->segment_size = vcm->cfg.segment_size;
+      a->preallocated_fifo_pairs = vcm->cfg.preallocated_fifo_pairs;
+      a->rx_fifo_size = vcm->cfg.rx_fifo_size;
+      a->tx_fifo_size = vcm->cfg.tx_fifo_size;
+
+      rv = svm_fifo_segment_create (a);
+      if (PREDICT_FALSE (rv))
+	{
+	  clib_warning ("[%d] ERROR: sid %u: "
+			"svm_fifo_segment_create ('%s') failed! rv %d",
+			getpid (), client_session_index, a->segment_name, rv);
+	  vec_reset_length (a->new_segment_indices);
+	  rv = VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
+	  vppcom_send_connect_session_reply (client_session, rv);
+	  clib_spinlock_unlock (&vcm->sessions_lockp);
+	  rv = VPPCOM_ENOMEM;
+	  goto done;
+	}
+
+      client_session->segment_name = vec_dup ((u8 *) a->segment_name);
+      client_session->sm_seg_index = a->new_segment_indices[0];
+      vec_free (a->new_segment_indices);
+
+      seg = svm_fifo_segment_get_segment (client_session->sm_seg_index);
+      client_session->server_rx_fifo =
+	svm_fifo_segment_alloc_fifo (seg, vcm->cfg.rx_fifo_size,
+				     FIFO_SEGMENT_RX_FREELIST);
+      if (PREDICT_FALSE (!client_session->server_rx_fifo))
+	{
+	  svm_fifo_segment_delete (seg);
+	  clib_warning ("[%d] ERROR: sid %u: rx fifo alloc failed! "
+			"size %ld (0x%lx)", getpid (),
+			client_session_index,
+			vcm->cfg.rx_fifo_size, vcm->cfg.rx_fifo_size);
+	  rv = VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
+	  vppcom_send_connect_session_reply (client_session, rv);
+	  clib_spinlock_unlock (&vcm->sessions_lockp);
+	  rv = VPPCOM_ENOMEM;
+	  goto done;
+	}
+      client_session->server_rx_fifo->master_session_index =
+	client_session_index;
+
+      client_session->server_tx_fifo =
+	svm_fifo_segment_alloc_fifo (seg, vcm->cfg.tx_fifo_size,
+				     FIFO_SEGMENT_TX_FREELIST);
+      if (PREDICT_FALSE (!client_session->server_tx_fifo))
+	{
+	  svm_fifo_segment_delete (seg);
+	  clib_warning ("[%d] ERROR: sid %u: tx fifo alloc failed! "
+			"size %ld (0x%lx)",
+			getpid (), client_session_index,
+			vcm->cfg.tx_fifo_size, vcm->cfg.tx_fifo_size);
+	  rv = VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
+	  vppcom_send_connect_session_reply (client_session, rv);
+	  clib_spinlock_unlock (&vcm->sessions_lockp);
+	  rv = VPPCOM_ENOMEM;
+	  goto done;
+	}
+      client_session->server_tx_fifo->master_session_index =
+	client_session_index;
+
+      if (VPPCOM_DEBUG > 1)
+	clib_warning ("[%d] sid %u: created segment '%s', "
+		      "rx_fifo %p, tx_fifo %p",
+		      getpid (), client_session_index,
+		      client_session->segment_name,
+		      client_session->server_rx_fifo,
+		      client_session->server_tx_fifo);
+
+#ifdef CUT_THRU_EVENT_QUEUE	/* TBD */
+      {
+	void *oldheap;
+	ssvm_shared_header_t *sh = seg->ssvm.sh;
+
+	ssvm_lock_non_recursive (sh, 1);
+	oldheap = ssvm_push_heap (sh);
+	event_q = client_session->vpp_event_queue =
+	  unix_shared_memory_queue_init (vcm->cfg.event_queue_size,
+					 sizeof (session_fifo_event_t),
+					 getpid (), 0 /* signal not sent */ );
+	ssvm_pop_heap (oldheap);
+	ssvm_unlock_non_recursive (sh);
+      }
+#endif
+      vppcom_send_connect_session_reply (client_session, 0);
+    }
+  else
+    {
+      cut_thru_str = " ";
+      vppcom_send_accept_session_reply (client_session->vpp_handle, 0);
+    }
+
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] sid %d, accepted peer address %U peer port %u",
-		  vcm->my_pid, client_session_index, format_ip46_address,
-		  &client_session->peer_addr.ip46,
-		  client_session->peer_addr.is_ip4,
-		  clib_net_to_host_u16 (client_session->peer_port));
+    clib_warning ("[%d] sid %u: accepted%sconnection to local %s address "
+		  "%U port %u",
+		  getpid (), client_session_index, cut_thru_str,
+		  client_session->lcl_addr.is_ip4 ? "IPv4" : "IPv6",
+		  format_ip46_address, &client_session->lcl_addr.ip46,
+		  client_session->lcl_addr.is_ip4,
+		  clib_net_to_host_u16 (client_session->lcl_port));
+
   clib_spinlock_unlock (&vcm->sessions_lockp);
-  return (int) client_session_index;
+  rv = (int) client_session_index;
+done:
+  return rv;
 }
 
 int
 vppcom_session_connect (uint32_t session_index, vppcom_endpt_t * server_ep)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session = 0;
   int rv;
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (session_index, &session);
-  if (PREDICT_FALSE (rv))
+  VCL_LOCK_AND_GET_SESSION (session_index, &session);
+
+  if (PREDICT_FALSE (session->is_vep))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, session_index);
-      return rv;
+      clib_warning ("[%d] ERROR: sid %u: cannot connect on an epoll session!",
+		    getpid (), session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
 
-  if (session->is_vep)
+  if (PREDICT_FALSE (session->is_server))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) is an epoll session!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_EBADFD;
+      clib_warning ("[%d] ERROR: sid %u: is in use as a server session!",
+		    getpid (), session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
 
-  if (session->state == STATE_CONNECT)
+  if (PREDICT_FALSE (session->state & CLIENT_STATE_OPEN))
     {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] session, sid (%u) already connected!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_OK;
+	clib_warning ("[%d] sid %u: session already connected to "
+		      "%s %U port %d proto %s, state 0x%x (%s)",
+		      getpid (), session_index,
+		      session->peer_addr.is_ip4 ? "IPv4" : "IPv6",
+		      format_ip46_address,
+		      &session->peer_addr.ip46, session->peer_addr.is_ip4,
+		      clib_net_to_host_u16 (session->peer_port),
+		      session->proto ? "UDP" : "TCP", session->state,
+		      vppcom_session_state_str (session->state));
+
+      clib_spinlock_unlock (&vcm->sessions_lockp);
+      rv = VPPCOM_OK;
+      goto done;
     }
 
   session->vrf = server_ep->vrf;
@@ -2208,153 +2527,232 @@ vppcom_session_connect (uint32_t session_index, vppcom_endpt_t * server_ep)
   session->peer_port = server_ep->port;
 
   if (VPPCOM_DEBUG > 0)
-    {
-      u8 *ip_str = format (0, "%U", format_ip46_address,
-			   &session->peer_addr.ip46,
-			   session->peer_addr.is_ip4);
-      clib_warning ("[%d] connect sid %d to %s server port %d proto %s",
-		    vcm->my_pid, session_index, ip_str,
-		    clib_net_to_host_u16 (session->peer_port),
-		    session->proto ? "UDP" : "TCP");
-      vec_free (ip_str);
-    }
+    clib_warning ("[%d] sid %u: connecting to server %s %U port %d proto %s",
+		  getpid (), session_index,
+		  session->peer_addr.is_ip4 ? "IPv4" : "IPv6",
+		  format_ip46_address,
+		  &session->peer_addr.ip46, session->peer_addr.is_ip4,
+		  clib_net_to_host_u16 (session->peer_port),
+		  session->proto ? "UDP" : "TCP");
 
   vppcom_send_connect_sock (session, session_index);
   clib_spinlock_unlock (&vcm->sessions_lockp);
+
   rv = vppcom_wait_for_session_state_change (session_index, STATE_CONNECT,
 					     vcm->cfg.session_timeout);
   if (PREDICT_FALSE (rv))
     {
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] connect timed out, rv = %s (%d)",
-		      vcm->my_pid, vppcom_retval_str (rv), rv);
-      return rv;
+	clib_warning ("[%d] sid %u: connect failed! returning %d (%s)",
+		      getpid (), session_index, rv, vppcom_retval_str (rv));
     }
-  if (VPPCOM_DEBUG > 0)
-    clib_warning ("[%d] sid %d connected!", vcm->my_pid, session_index);
+  else if (VPPCOM_DEBUG > 0)
+    clib_warning ("[%d] sid %d: connected!", getpid (), session_index);
 
-  return VPPCOM_OK;
+done:
+  return rv;
 }
 
-int
-vppcom_session_read (uint32_t session_index, void *buf, int n)
+static inline int
+vppcom_session_read_internal (uint32_t session_index, void *buf, int n,
+			      u8 peek)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session = 0;
   svm_fifo_t *rx_fifo;
   int n_read = 0;
   int rv;
   char *fifo_str;
   u32 poll_et;
+  session_state_t state;
+  u8 is_server;
+  u8 is_nonblocking;
 
   ASSERT (buf);
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (session_index, &session);
-  if (PREDICT_FALSE (rv))
-    {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, session_index);
-      return rv;
-    }
+  VCL_LOCK_AND_GET_SESSION (session_index, &session);
 
-  if (session->is_vep)
+  if (PREDICT_FALSE (session->is_vep))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) is an epoll session!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_EBADFD;
+      clib_warning ("[%d] ERROR: sid %u: cannot read from an epoll session!",
+		    getpid (), session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
 
-  if (session->state == STATE_DISCONNECT)
+  is_server = session->is_server;
+  is_nonblocking = session->is_nonblocking;
+  state = session->state;
+  if (PREDICT_FALSE (!(state & (SERVER_STATE_OPEN | CLIENT_STATE_OPEN))))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
+      rv = ((state == STATE_DISCONNECT) ?
+	    VPPCOM_ECONNRESET : VPPCOM_ENOTCONN);
+
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] sid (%u) has been closed by remote peer!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_ECONNRESET;
+	clib_warning ("[%d] sid %u: %s session is not open! "
+		      "state 0x%x (%s), returning %d (%s)",
+		      getpid (), session_index, is_server ?
+		      "server" : "client", state,
+		      vppcom_session_state_str (state),
+		      rv, vppcom_retval_str (rv));
+      goto done;
     }
 
-  rx_fifo = ((!session->is_cut_thru || session->is_server) ?
+  rx_fifo = ((!session->is_cut_thru || is_server) ?
 	     session->server_rx_fifo : session->server_tx_fifo);
-  fifo_str = ((!session->is_cut_thru || session->is_server) ?
+  fifo_str = ((!session->is_cut_thru || is_server) ?
 	      "server_rx_fifo" : "server_tx_fifo");
-  poll_et = EPOLLET & session->vep.ev.events;
   clib_spinlock_unlock (&vcm->sessions_lockp);
 
   do
     {
-      n_read = svm_fifo_dequeue_nowait (rx_fifo, n, buf);
+      if (peek)
+	n_read = svm_fifo_peek (rx_fifo, 0, n, buf);
+      else
+	n_read = svm_fifo_dequeue_nowait (rx_fifo, n, buf);
     }
-  while (!session->is_nonblocking && (n_read <= 0));
+  while (!is_nonblocking && (n_read <= 0));
 
-  if (poll_et && (n_read <= 0))
+  if (n_read <= 0)
     {
-      clib_spinlock_lock (&vcm->sessions_lockp);
-      session->vep.et_mask |= EPOLLIN;
+      VCL_LOCK_AND_GET_SESSION (session_index, &session);
+
+      poll_et = (((EPOLLET | EPOLLIN) & session->vep.ev.events) ==
+		 (EPOLLET | EPOLLIN));
+      if (poll_et)
+	session->vep.et_mask |= EPOLLIN;
+
+      if (state == STATE_CLOSE_ON_EMPTY)
+	{
+	  session_state_t new_state = STATE_DISCONNECT;
+	  rv = VPPCOM_ECONNRESET;
+
+	  if (VPPCOM_DEBUG > 1)
+	    {
+	      clib_warning ("[%d] sid %u: Empty fifo with %s session "
+			    "state 0x%x (%s)!\n"
+			    "  Setting state to %d (%s), returning %d (%s)",
+			    getpid (), session_index,
+			    is_server ? "server" : "client",
+			    state, vppcom_session_state_str (state),
+			    new_state, vppcom_session_state_str (new_state),
+			    rv, vppcom_retval_str (rv));
+	    }
+
+	  session->state = new_state;
+	}
+      else
+	rv = VPPCOM_EAGAIN;
+
       clib_spinlock_unlock (&vcm->sessions_lockp);
     }
+  else
+    rv = n_read;
+
+  if (VPPCOM_DEBUG > 2)
+    {
+      if (rv > 0)
+	clib_warning ("[%d] sid %u: read %d bytes from %s (%p)", getpid (),
+		      session_index, n_read, fifo_str, rx_fifo);
+      else
+	clib_warning ("[%d] sid %u: nothing read, returning %d (%s)",
+		      getpid (), session_index, rv, vppcom_retval_str (rv));
+    }
+done:
+  return rv;
+}
 
-  if ((VPPCOM_DEBUG > 2) && (n_read > 0))
-    clib_warning ("[%d] sid %d, read %d bytes from %s (%p)", vcm->my_pid,
-		  session_index, n_read, fifo_str, rx_fifo);
+int
+vppcom_session_read (uint32_t session_index, void *buf, int n)
+{
+  return (vppcom_session_read_internal (session_index, buf, n, 0));
+}
 
-  return (n_read <= 0) ? VPPCOM_EAGAIN : n_read;
+static int
+vppcom_session_peek (uint32_t session_index, void *buf, int n)
+{
+  return (vppcom_session_read_internal (session_index, buf, n, 1));
 }
 
 static inline int
 vppcom_session_read_ready (session_t * session, u32 session_index)
 {
-  vppcom_main_t *vcm = &vppcom_main;
-  svm_fifo_t *rx_fifo;
+  svm_fifo_t *rx_fifo = 0;
   int ready = 0;
+  u32 poll_et;
+  int rv;
+  u8 is_server = session->is_server;
+  session_state_t state = session->state;
 
   /* Assumes caller has acquired spinlock: vcm->sessions_lockp */
-  if (session->is_vep)
-    {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) is an epoll session!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_EBADFD;
-    }
-
-  if (session->state == STATE_DISCONNECT)
+  if (PREDICT_FALSE (session->is_vep))
     {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] sid (%u) has been closed by remote peer!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_ECONNRESET;
+      clib_warning ("[%d] ERROR: sid %u: cannot read from an "
+		    "epoll session!", getpid (), session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
 
   if (session->is_listen)
     ready = clib_fifo_elts (vcm->client_session_index_fifo);
   else
     {
-      rx_fifo = ((!session->is_cut_thru || session->is_server) ?
+      if (!(state & (SERVER_STATE_OPEN | CLIENT_STATE_OPEN | STATE_LISTEN)))
+	{
+	  rv = ((state == STATE_DISCONNECT) ? VPPCOM_ECONNRESET :
+		VPPCOM_ENOTCONN);
+
+	  if (VPPCOM_DEBUG > 1)
+	    clib_warning ("[%d] sid %u: %s session is not open! "
+			  "state 0x%x (%s), returning %d (%s)", getpid (),
+			  session_index, is_server ? "server" : "client",
+			  state, vppcom_session_state_str (state),
+			  rv, vppcom_retval_str (rv));
+	  goto done;
+	}
+
+      rx_fifo = ((!session->is_cut_thru || is_server) ?
 		 session->server_rx_fifo : session->server_tx_fifo);
 
       ready = svm_fifo_max_dequeue (rx_fifo);
     }
 
-  if (VPPCOM_DEBUG > 3)
-    clib_warning ("[%d] sid %d, peek %s (%p), ready = %d", vcm->my_pid,
-		  session_index,
-		  session->is_server ? "server_rx_fifo" : "server_tx_fifo",
-		  rx_fifo, ready);
-  if ((session->vep.ev.events & EPOLLET) && (ready == 0))
-    session->vep.et_mask |= EPOLLIN;
+  if (ready == 0)
+    {
+      poll_et =
+	((EPOLLET | EPOLLIN) & session->vep.ev.events) == (EPOLLET | EPOLLIN);
+      if (poll_et)
+	session->vep.et_mask |= EPOLLIN;
+
+      if (state == STATE_CLOSE_ON_EMPTY)
+	{
+	  rv = VPPCOM_ECONNRESET;
+	  session_state_t new_state = STATE_DISCONNECT;
 
-  return ready;
+	  if (VPPCOM_DEBUG > 1)
+	    {
+	      clib_warning ("[%d] sid %u: Empty fifo with %s session "
+			    "state 0x%x (%s)!\n"
+			    "  Setting state to %d (%s), returning %d (%s)",
+			    getpid (), session_index,
+			    is_server ? "server" : "client",
+			    state, vppcom_session_state_str (state),
+			    new_state, vppcom_session_state_str (new_state),
+			    rv, vppcom_retval_str (rv));
+	    }
+	  session->state = new_state;
+	  goto done;
+	}
+    }
+  rv = ready;
+done:
+  return rv;
 }
 
 int
 vppcom_session_write (uint32_t session_index, void *buf, int n)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session = 0;
   svm_fifo_t *tx_fifo;
   unix_shared_memory_queue_t *q;
@@ -2362,117 +2760,162 @@ vppcom_session_write (uint32_t session_index, void *buf, int n)
   int rv, n_write;
   char *fifo_str;
   u32 poll_et;
+  u8 is_server;
+  u8 is_nonblocking;
+  session_state_t state;
 
   ASSERT (buf);
 
-  clib_spinlock_lock (&vcm->sessions_lockp);
-  rv = vppcom_session_at_index (session_index, &session);
-  if (PREDICT_FALSE (rv))
-    {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-		      vcm->my_pid, session_index);
-      return rv;
-    }
+  VCL_LOCK_AND_GET_SESSION (session_index, &session);
 
-  if (session->is_vep)
+  if (PREDICT_FALSE (session->is_vep))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) is an epoll session!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_EBADFD;
+      clib_warning ("[%d] ERROR: sid %u: cannot write to an epoll session!",
+		    getpid (), session_index);
+
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
 
-  if (session->state == STATE_DISCONNECT)
+  is_server = session->is_server;
+  is_nonblocking = session->is_nonblocking;
+  state = session->state;
+  if (!(state & (SERVER_STATE_OPEN | CLIENT_STATE_OPEN)))
     {
+      rv = ((state == STATE_DISCONNECT) ? VPPCOM_ECONNRESET :
+	    VPPCOM_ENOTCONN);
+
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] sid (%u) has been closed by remote peer!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_ECONNRESET;
+      if (VPPCOM_DEBUG > 1)
+	clib_warning ("[%d] sid %u: %s session is not open! state 0x%x (%s)",
+		      getpid (), session_index, is_server ?
+		      "server" : "client", state,
+		      vppcom_session_state_str (state));
+      goto done;
     }
 
-  tx_fifo = ((!session->is_cut_thru || session->is_server) ?
+  tx_fifo = ((!session->is_cut_thru || is_server) ?
 	     session->server_tx_fifo : session->server_rx_fifo);
-  fifo_str = ((!session->is_cut_thru || session->is_server) ?
+  fifo_str = ((!session->is_cut_thru || is_server) ?
 	      "server_tx_fifo" : "server_rx_fifo");
-  q = session->vpp_event_queue;
-  poll_et = EPOLLET & session->vep.ev.events;
   clib_spinlock_unlock (&vcm->sessions_lockp);
 
   do
     {
       n_write = svm_fifo_enqueue_nowait (tx_fifo, n, buf);
     }
-  while (!session->is_nonblocking && (n_write <= 0));
+  while (!is_nonblocking && (n_write <= 0));
 
   /* If event wasn't set, add one */
   if (!session->is_cut_thru && (n_write > 0) && svm_fifo_set_event (tx_fifo))
     {
-      int rval;
-
       /* Fabricate TX event, send to vpp */
       evt.fifo = tx_fifo;
       evt.event_type = FIFO_EVENT_APP_TX;
 
-      rval = vppcom_session_at_index (session_index, &session);
-      if (PREDICT_FALSE (rval))
-	{
-	  if (VPPCOM_DEBUG > 1)
-	    clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-			  vcm->my_pid, session_index);
-	  return rval;
-	}
+      VCL_LOCK_AND_GET_SESSION (session_index, &session);
+      q = session->vpp_event_queue;
       ASSERT (q);
       unix_shared_memory_queue_add (q, (u8 *) & evt,
 				    0 /* do wait for mutex */ );
+      clib_spinlock_unlock (&vcm->sessions_lockp);
+      if (VPPCOM_DEBUG > 1)
+	clib_warning ("[%d] sid %u: added FIFO_EVENT_APP_TX to "
+		      "vpp_event_q %p, n_write %d", getpid (),
+		      session_index, q, n_write);
     }
 
-  if (poll_et && (n_write <= 0))
+  if (n_write <= 0)
     {
-      clib_spinlock_lock (&vcm->sessions_lockp);
-      session->vep.et_mask |= EPOLLOUT;
+      VCL_LOCK_AND_GET_SESSION (session_index, &session);
+
+      poll_et = (((EPOLLET | EPOLLOUT) & session->vep.ev.events) ==
+		 (EPOLLET | EPOLLOUT));
+      if (poll_et)
+	session->vep.et_mask |= EPOLLOUT;
+
+      if (state == STATE_CLOSE_ON_EMPTY)
+	{
+	  session_state_t new_state = STATE_DISCONNECT;
+	  rv = VPPCOM_ECONNRESET;
+
+	  if (VPPCOM_DEBUG > 1)
+	    {
+	      clib_warning ("[%d] sid %u: Empty fifo with %s session "
+			    "state 0x%x (%s)!\n"
+			    "  Setting state to %d (%s), returning %d (%s)",
+			    getpid (), session_index,
+			    is_server ? "server" : "client",
+			    state, vppcom_session_state_str (state),
+			    new_state, vppcom_session_state_str (new_state),
+			    rv, vppcom_retval_str (rv));
+	    }
+
+	  session->state = new_state;
+	}
+      else
+	rv = VPPCOM_EAGAIN;
+
       clib_spinlock_unlock (&vcm->sessions_lockp);
     }
+  else
+    rv = n_write;
 
   if (VPPCOM_DEBUG > 2)
     {
-      if (n_write == -2)
-	clib_warning ("[%d] sid %d, FIFO-FULL %s (%p)", vcm->my_pid,
+      if (n_write <= 0)
+	clib_warning ("[%d] sid %u: FIFO-FULL %s (%p)", getpid (),
 		      session_index, fifo_str, tx_fifo);
       else
-	clib_warning ("[%d] sid %d, wrote %d bytes to %s (%p)", vcm->my_pid,
+	clib_warning ("[%d] sid %u: wrote %d bytes to %s (%p)", getpid (),
 		      session_index, n_write, fifo_str, tx_fifo);
     }
-  return (n_write < 0) ? VPPCOM_EAGAIN : n_write;
+done:
+  return rv;
 }
 
 static inline int
 vppcom_session_write_ready (session_t * session, u32 session_index)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   svm_fifo_t *tx_fifo;
   char *fifo_str;
   int ready;
+  u32 poll_et;
+  int rv;
+  u8 is_server = session->is_server;
+  session_state_t state = session->state;
 
   /* Assumes caller has acquired spinlock: vcm->sessions_lockp */
-  if (session->is_vep)
+  if (PREDICT_FALSE (session->is_vep))
     {
-      clib_spinlock_unlock (&vcm->sessions_lockp);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] invalid session, sid (%u) is an epoll session!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_EBADFD;
+      clib_warning ("[%d] ERROR: sid %u: cannot write to an "
+		    "epoll session!", getpid (), session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
     }
 
-  if (session->state == STATE_DISCONNECT)
+  if (PREDICT_FALSE (session->is_listen))
     {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("[%d] sid (%u) has been closed by remote peer!",
-		      vcm->my_pid, session_index);
-      return VPPCOM_ECONNRESET;
+      clib_warning ("[%d] ERROR: sid %u: cannot write to a listen session!",
+		    getpid (), session_index);
+      rv = VPPCOM_EBADFD;
+      goto done;
+    }
+
+  if (!(state & (SERVER_STATE_OPEN | CLIENT_STATE_OPEN)))
+    {
+      session_state_t state = session->state;
+
+      rv = ((state == STATE_DISCONNECT) ? VPPCOM_ECONNRESET :
+	    VPPCOM_ENOTCONN);
+
+      clib_warning ("[%d] ERROR: sid %u: %s session is not open! "
+		    "state 0x%x (%s), returning %d (%s)", getpid (),
+		    session_index, is_server ? "server" : "client",
+		    state, vppcom_session_state_str (state),
+		    rv, vppcom_retval_str (rv));
+      goto done;
     }
 
   tx_fifo = ((!session->is_cut_thru || session->is_server) ?
@@ -2483,12 +2926,39 @@ vppcom_session_write_ready (session_t * session, u32 session_index)
   ready = svm_fifo_max_enqueue (tx_fifo);
 
   if (VPPCOM_DEBUG > 3)
-    clib_warning ("[%d] sid %d, peek %s (%p), ready = %d", vcm->my_pid,
+    clib_warning ("[%d] sid %u: peek %s (%p), ready = %d", getpid (),
 		  session_index, fifo_str, tx_fifo, ready);
-  if ((session->vep.ev.events & EPOLLET) && (ready == 0))
-    session->vep.et_mask |= EPOLLOUT;
 
-  return ready;
+  if (ready == 0)
+    {
+      poll_et = (((EPOLLET | EPOLLOUT) & session->vep.ev.events) ==
+		 (EPOLLET | EPOLLOUT));
+      if (poll_et)
+	session->vep.et_mask |= EPOLLOUT;
+
+      if (state == STATE_CLOSE_ON_EMPTY)
+	{
+	  rv = VPPCOM_ECONNRESET;
+	  session_state_t new_state = STATE_DISCONNECT;
+
+	  if (VPPCOM_DEBUG > 1)
+	    {
+	      clib_warning ("[%d] sid %u: Empty fifo with %s session "
+			    "state 0x%x (%s)!\n"
+			    "  Setting state to %d (%s), returning %d (%s)",
+			    getpid (), session_index,
+			    is_server ? "server" : "client",
+			    state, vppcom_session_state_str (state),
+			    new_state, vppcom_session_state_str (new_state),
+			    rv, vppcom_retval_str (rv));
+	    }
+	  session->state = new_state;
+	  goto done;
+	}
+    }
+  rv = ready;
+done:
+  return rv;
 }
 
 int
@@ -2496,7 +2966,6 @@ vppcom_select (unsigned long n_bits, unsigned long *read_map,
 	       unsigned long *write_map, unsigned long *except_map,
 	       double time_to_wait)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   u32 session_index;
   session_t *session = 0;
   int rv, bits_set = 0;
@@ -2540,7 +3009,7 @@ vppcom_select (unsigned long n_bits, unsigned long *read_map,
                       clib_spinlock_unlock (&vcm->sessions_lockp);
                       if (VPPCOM_DEBUG > 1)
                         clib_warning ("[%d] session %d specified in "
-                                      "read_map is closed.", vcm->my_pid,
+                                      "read_map is closed.", getpid (),
                                       session_index);
                       bits_set = VPPCOM_EBADFD;
                       goto select_done;
@@ -2576,7 +3045,7 @@ vppcom_select (unsigned long n_bits, unsigned long *read_map,
                       clib_spinlock_unlock (&vcm->sessions_lockp);
                       if (VPPCOM_DEBUG > 0)
                         clib_warning ("[%d] session %d specified in "
-                                      "write_map is closed.", vcm->my_pid,
+                                      "write_map is closed.", getpid (),
                                       session_index);
                       bits_set = VPPCOM_EBADFD;
                       goto select_done;
@@ -2604,7 +3073,7 @@ vppcom_select (unsigned long n_bits, unsigned long *read_map,
                       clib_spinlock_unlock (&vcm->sessions_lockp);
                       if (VPPCOM_DEBUG > 1)
                         clib_warning ("[%d] session %d specified in "
-                                      "except_map is closed.", vcm->my_pid,
+                                      "except_map is closed.", getpid (),
                                       session_index);
                       bits_set = VPPCOM_EBADFD;
                       goto select_done;
@@ -2635,86 +3104,83 @@ vep_verify_epoll_chain (u32 vep_idx)
   session_t *session;
   vppcom_epoll_t *vep;
   int rv;
-  u32 sid;
+  u32 sid = vep_idx;
 
-  if (VPPCOM_DEBUG < 1)
+  if (VPPCOM_DEBUG <= 1)
     return;
 
   /* Assumes caller has acquired spinlock: vcm->sessions_lockp */
   rv = vppcom_session_at_index (vep_idx, &session);
   if (PREDICT_FALSE (rv))
     {
-      clib_warning ("ERROR: Invalid vep_idx (%u)!", vep_idx);
+      clib_warning ("[%d] ERROR: Invalid vep_idx (%u)!", getpid (), vep_idx);
       goto done;
     }
   if (PREDICT_FALSE (!session->is_vep))
     {
-      clib_warning ("ERROR: vep_idx (%u) is not a vep!", vep_idx);
+      clib_warning ("[%d] ERROR: vep_idx (%u) is not a vep!", getpid (),
+		    vep_idx);
       goto done;
     }
-  if (VPPCOM_DEBUG > 1)
-    clib_warning ("vep_idx (%u): Dumping epoll chain\n"
-		  "{\n"
-		  "   is_vep         = %u\n"
-		  "   is_vep_session = %u\n"
-		  "   wait_cont_idx  = 0x%x (%u)\n"
-		  "}\n",
-		  vep_idx, session->is_vep, session->is_vep_session,
-		  session->wait_cont_idx, session->wait_cont_idx);
-  do
-    {
-      vep = &session->vep;
-      sid = vep->next_sid;
-      if (session->is_vep_session)
+  vep = &session->vep;
+  clib_warning ("[%d] vep_idx (%u): Dumping epoll chain\n"
+		"{\n"
+		"   is_vep         = %u\n"
+		"   is_vep_session = %u\n"
+		"   next_sid       = 0x%x (%u)\n"
+		"   wait_cont_idx  = 0x%x (%u)\n"
+		"}\n", getpid (), vep_idx,
+		session->is_vep, session->is_vep_session,
+		vep->next_sid, vep->next_sid,
+		session->wait_cont_idx, session->wait_cont_idx);
+
+  for (sid = vep->next_sid; sid != ~0; sid = vep->next_sid)
+    {
+      rv = vppcom_session_at_index (sid, &session);
+      if (PREDICT_FALSE (rv))
 	{
-	  if (VPPCOM_DEBUG > 1)
-	    clib_warning ("vep_idx[%u]: sid 0x%x (%u)\n"
-			  "{\n"
-			  "   next_sid       = 0x%x (%u)\n"
-			  "   prev_sid       = 0x%x (%u)\n"
-			  "   vep_idx        = 0x%x (%u)\n"
-			  "   ev.events      = 0x%x\n"
-			  "   ev.data.u64    = 0x%llx\n"
-			  "   et_mask        = 0x%x\n"
-			  "}\n",
-			  vep_idx, sid, sid,
-			  vep->next_sid, vep->next_sid,
-			  vep->prev_sid, vep->prev_sid,
-			  vep->vep_idx, vep->vep_idx,
-			  vep->ev.events, vep->ev.data.u64, vep->et_mask);
+	  clib_warning ("[%d] ERROR: Invalid sid (%u)!", getpid (), sid);
+	  goto done;
 	}
-      if (sid != ~0)
+      if (PREDICT_FALSE (session->is_vep))
+	clib_warning ("[%d] ERROR: sid (%u) is a vep!", getpid (), vep_idx);
+      else if (PREDICT_FALSE (!session->is_vep_session))
 	{
-	  rv = vppcom_session_at_index (sid, &session);
-	  if (PREDICT_FALSE (rv))
-	    {
-	      clib_warning ("ERROR: Invalid sid (%u)!", sid);
-	      goto done;
-	    }
-	  if (PREDICT_FALSE (session->is_vep))
-	    clib_warning ("ERROR: sid (%u) is a vep!", vep_idx);
-	  else if (PREDICT_FALSE (!session->is_vep_session))
-	    {
-	      clib_warning ("ERROR: session (%u) is not a vep session!", sid);
-	      goto done;
-	    }
-	  if (PREDICT_FALSE (session->vep.vep_idx != vep_idx))
-	    clib_warning ("ERROR: session (%u) vep_idx (%u) != "
-			  "vep_idx (%u)!",
-			  sid, session->vep.vep_idx, vep_idx);
+	  clib_warning ("[%d] ERROR: session (%u) is not a vep session!",
+			getpid (), sid);
+	  goto done;
+	}
+      vep = &session->vep;
+      if (PREDICT_FALSE (vep->vep_idx != vep_idx))
+	clib_warning ("[%d] ERROR: session (%u) vep_idx (%u) != "
+		      "vep_idx (%u)!", getpid (),
+		      sid, session->vep.vep_idx, vep_idx);
+      if (session->is_vep_session)
+	{
+	  clib_warning ("vep_idx[%u]: sid 0x%x (%u)\n"
+			"{\n"
+			"   next_sid       = 0x%x (%u)\n"
+			"   prev_sid       = 0x%x (%u)\n"
+			"   vep_idx        = 0x%x (%u)\n"
+			"   ev.events      = 0x%x\n"
+			"   ev.data.u64    = 0x%llx\n"
+			"   et_mask        = 0x%x\n"
+			"}\n",
+			vep_idx, sid, sid,
+			vep->next_sid, vep->next_sid,
+			vep->prev_sid, vep->prev_sid,
+			vep->vep_idx, vep->vep_idx,
+			vep->ev.events, vep->ev.data.u64, vep->et_mask);
 	}
     }
-  while (sid != ~0);
 
 done:
-  if (VPPCOM_DEBUG > 1)
-    clib_warning ("vep_idx (%u): Dump complete!", vep_idx);
+  clib_warning ("[%d] vep_idx (%u): Dump complete!\n", getpid (), vep_idx);
 }
 
 int
 vppcom_epoll_create (void)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *vep_session;
   u32 vep_idx;
 
@@ -2728,10 +3194,11 @@ vppcom_epoll_create (void)
   vep_session->vep.next_sid = ~0;
   vep_session->vep.prev_sid = ~0;
   vep_session->wait_cont_idx = ~0;
+  vep_session->vpp_handle = ~0;
   clib_spinlock_unlock (&vcm->sessions_lockp);
 
   if (VPPCOM_DEBUG > 0)
-    clib_warning ("Created vep_idx %u!", vep_idx);
+    clib_warning ("[%d] Created vep_idx %u!", getpid (), vep_idx);
 
   return (vep_idx);
 }
@@ -2740,15 +3207,14 @@ int
 vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
 		  struct epoll_event *event)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *vep_session;
   session_t *session;
   int rv;
 
   if (vep_idx == session_index)
     {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("ERROR: vep_idx == session_index (%u)!", vep_idx);
+      clib_warning ("[%d] ERROR: vep_idx == session_index (%u)!",
+		    getpid (), vep_idx);
       return VPPCOM_EINVAL;
     }
 
@@ -2756,14 +3222,13 @@ vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
   rv = vppcom_session_at_index (vep_idx, &vep_session);
   if (PREDICT_FALSE (rv))
     {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("ERROR: Invalid vep_idx (%u)!", vep_idx);
+      clib_warning ("[%d] ERROR: Invalid vep_idx (%u)!", vep_idx);
       goto done;
     }
   if (PREDICT_FALSE (!vep_session->is_vep))
     {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("ERROR: vep_idx (%u) is not a vep!", vep_idx);
+      clib_warning ("[%d] ERROR: vep_idx (%u) is not a vep!",
+		    getpid (), vep_idx);
       rv = VPPCOM_EINVAL;
       goto done;
     }
@@ -2775,13 +3240,13 @@ vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
   if (PREDICT_FALSE (rv))
     {
       if (VPPCOM_DEBUG > 0)
-	clib_warning ("ERROR: Invalid session_index (%u)!", session_index);
+	clib_warning ("[%d] ERROR: Invalid session_index (%u)!",
+		      getpid (), session_index);
       goto done;
     }
   if (PREDICT_FALSE (session->is_vep))
     {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("ERROR: session_index (%u) is a vep!", vep_idx);
+      clib_warning ("ERROR: session_index (%u) is a vep!", vep_idx);
       rv = VPPCOM_EINVAL;
       goto done;
     }
@@ -2791,7 +3256,8 @@ vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
     case EPOLL_CTL_ADD:
       if (PREDICT_FALSE (!event))
 	{
-	  clib_warning ("NULL pointer to epoll_event structure!");
+	  clib_warning ("[%d] ERROR: EPOLL_CTL_ADD: NULL pointer to "
+			"epoll_event structure!", getpid ());
 	  rv = VPPCOM_EINVAL;
 	  goto done;
 	}
@@ -2802,10 +3268,9 @@ vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
 					&next_session);
 	  if (PREDICT_FALSE (rv))
 	    {
-	      if (VPPCOM_DEBUG > 0)
-		clib_warning ("EPOLL_CTL_ADD: Invalid vep.next_sid (%u) on"
-			      " vep_idx (%u)!", vep_session->vep.next_sid,
-			      vep_idx);
+	      clib_warning ("[%d] ERROR: EPOLL_CTL_ADD: Invalid "
+			    "vep.next_sid (%u) on vep_idx (%u)!",
+			    getpid (), vep_session->vep.next_sid, vep_idx);
 	      goto done;
 	    }
 	  ASSERT (next_session->vep.prev_sid == vep_idx);
@@ -2816,59 +3281,61 @@ vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
       session->vep.vep_idx = vep_idx;
       session->vep.et_mask = VEP_DEFAULT_ET_MASK;
       session->vep.ev = *event;
+      session->is_vep = 0;
       session->is_vep_session = 1;
       vep_session->vep.next_sid = session_index;
       if (VPPCOM_DEBUG > 1)
-	clib_warning ("EPOLL_CTL_ADD: vep_idx %u, sid %u, events 0x%x,"
-		      " data 0x%llx!", vep_idx, session_index,
+	clib_warning ("[%d] EPOLL_CTL_ADD: vep_idx %u, sid %u, events 0x%x,"
+		      " data 0x%llx!", getpid (), vep_idx, session_index,
 		      event->events, event->data.u64);
       break;
 
     case EPOLL_CTL_MOD:
       if (PREDICT_FALSE (!event))
 	{
-	  clib_warning ("NULL pointer to epoll_event structure!");
+	  clib_warning ("[%d] ERROR: EPOLL_CTL_MOD: NULL pointer to "
+			"epoll_event structure!", getpid ());
 	  rv = VPPCOM_EINVAL;
 	  goto done;
 	}
-      if (PREDICT_FALSE (!session->is_vep_session &&
-			 (session->vep.vep_idx != vep_idx)))
+      else if (PREDICT_FALSE (!session->is_vep_session))
 	{
-	  if (VPPCOM_DEBUG > 0)
-	    {
-	      if (!session->is_vep_session)
-		clib_warning ("EPOLL_CTL_MOD: session (%u) is not "
-			      "a vep session!", session_index);
-	      else
-		clib_warning ("EPOLL_CTL_MOD: session (%u) vep_idx (%u) != "
-			      "vep_idx (%u)!", session_index,
-			      session->vep.vep_idx, vep_idx);
-	    }
+	  clib_warning ("[%d] ERROR: sid %u EPOLL_CTL_MOD: "
+			"not a vep session!", getpid (), session_index);
+	  rv = VPPCOM_EINVAL;
+	  goto done;
+	}
+      else if (PREDICT_FALSE (session->vep.vep_idx != vep_idx))
+	{
+	  clib_warning ("[%d] ERROR: sid %u EPOLL_CTL_MOD: "
+			"vep_idx (%u) != vep_idx (%u)!",
+			getpid (), session_index,
+			session->vep.vep_idx, vep_idx);
 	  rv = VPPCOM_EINVAL;
 	  goto done;
 	}
       session->vep.et_mask = VEP_DEFAULT_ET_MASK;
       session->vep.ev = *event;
       if (VPPCOM_DEBUG > 1)
-	clib_warning ("EPOLL_CTL_MOD: vep_idx %u, sid %u, events 0x%x,"
-		      " data 0x%llx!", vep_idx, session_index,
+	clib_warning ("[%d] EPOLL_CTL_MOD: vep_idx %u, sid %u, events 0x%x,"
+		      " data 0x%llx!", getpid (), vep_idx, session_index,
 		      event->events, event->data.u64);
       break;
 
     case EPOLL_CTL_DEL:
-      if (PREDICT_FALSE (!session->is_vep_session &&
-			 (session->vep.vep_idx != vep_idx)))
+      if (PREDICT_FALSE (!session->is_vep_session))
 	{
-	  if (VPPCOM_DEBUG > 0)
-	    {
-	      if (!session->is_vep_session)
-		clib_warning ("EPOLL_CTL_DEL: session (%u) is not "
-			      "a vep session!", session_index);
-	      else
-		clib_warning ("EPOLL_CTL_DEL: session (%u) vep_idx (%u) != "
-			      "vep_idx (%u)!", session_index,
-			      session->vep.vep_idx, vep_idx);
-	    }
+	  clib_warning ("[%d] ERROR: sid %u EPOLL_CTL_DEL: "
+			"not a vep session!", getpid (), session_index);
+	  rv = VPPCOM_EINVAL;
+	  goto done;
+	}
+      else if (PREDICT_FALSE (session->vep.vep_idx != vep_idx))
+	{
+	  clib_warning ("[%d] ERROR: sid %u EPOLL_CTL_DEL: "
+			"vep_idx (%u) != vep_idx (%u)!",
+			getpid (), session_index,
+			session->vep.vep_idx, vep_idx);
 	  rv = VPPCOM_EINVAL;
 	  goto done;
 	}
@@ -2885,10 +3352,9 @@ vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
 	  rv = vppcom_session_at_index (session->vep.prev_sid, &prev_session);
 	  if (PREDICT_FALSE (rv))
 	    {
-	      if (VPPCOM_DEBUG > 0)
-		clib_warning ("EPOLL_CTL_DEL: Invalid vep.prev_sid (%u) on"
-			      " sid (%u)!", session->vep.prev_sid,
-			      session_index);
+	      clib_warning ("[%d] ERROR: EPOLL_CTL_DEL: Invalid "
+			    "vep.prev_sid (%u) on sid (%u)!",
+			    getpid (), session->vep.prev_sid, session_index);
 	      goto done;
 	    }
 	  ASSERT (prev_session->vep.next_sid == session_index);
@@ -2900,10 +3366,9 @@ vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
 	  rv = vppcom_session_at_index (session->vep.next_sid, &next_session);
 	  if (PREDICT_FALSE (rv))
 	    {
-	      if (VPPCOM_DEBUG > 0)
-		clib_warning ("EPOLL_CTL_DEL: Invalid vep.next_sid (%u) on"
-			      " sid (%u)!", session->vep.next_sid,
-			      session_index);
+	      clib_warning ("[%d] ERROR: EPOLL_CTL_DEL: Invalid "
+			    "vep.next_sid (%u) on sid (%u)!",
+			    getpid (), session->vep.next_sid, session_index);
 	      goto done;
 	    }
 	  ASSERT (next_session->vep.prev_sid == session_index);
@@ -2916,12 +3381,12 @@ vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
       session->vep.vep_idx = ~0;
       session->is_vep_session = 0;
       if (VPPCOM_DEBUG > 1)
-	clib_warning ("EPOLL_CTL_DEL: vep_idx %u, sid %u!", vep_idx,
-		      session_index);
+	clib_warning ("[%d] EPOLL_CTL_DEL: vep_idx %u, sid %u!",
+		      getpid (), vep_idx, session_index);
       break;
 
     default:
-      clib_warning ("Invalid operation (%d)!", op);
+      clib_warning ("[%d] ERROR: Invalid operation (%d)!", getpid (), op);
       rv = VPPCOM_EINVAL;
     }
 
@@ -2932,45 +3397,22 @@ done:
   return rv;
 }
 
-#define VCL_LOCK_AND_GET_SESSION(I, S)                  \
-do {                                                    \
-  vppcom_main_t *vcm = &vppcom_main;                    \
-                                                        \
-  clib_spinlock_lock (&vcm->sessions_lockp);            \
-  rv = vppcom_session_at_index (I, S);                  \
-  if (PREDICT_FALSE (rv))                               \
-    {                                                   \
-      clib_spinlock_unlock (&vcm->sessions_lockp);      \
-                                                        \
-      if (VPPCOM_DEBUG > 0)                             \
-        clib_warning ("ERROR: Invalid ##I (%u)!", I);   \
-                                                        \
-      goto done;                                        \
-    }                                                   \
-} while (0)
-
 int
 vppcom_epoll_wait (uint32_t vep_idx, struct epoll_event *events,
 		   int maxevents, double wait_for_time)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *vep_session;
   int rv;
   f64 timeout = clib_time_now (&vcm->clib_time) + wait_for_time;
+  u32 keep_trying = 1;
   int num_ev = 0;
   u32 vep_next_sid, wait_cont_idx;
   u8 is_vep;
 
   if (PREDICT_FALSE (maxevents <= 0))
     {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("ERROR: Invalid maxevents (%d)!", maxevents);
-      return VPPCOM_EINVAL;
-    }
-  if (PREDICT_FALSE (wait_for_time < 0))
-    {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("ERROR: Invalid wait_for_time (%f)!", wait_for_time);
+      clib_warning ("[%d] ERROR: Invalid maxevents (%d)!",
+		    getpid (), maxevents);
       return VPPCOM_EINVAL;
     }
   memset (events, 0, sizeof (*events) * maxevents);
@@ -2983,14 +3425,16 @@ vppcom_epoll_wait (uint32_t vep_idx, struct epoll_event *events,
 
   if (PREDICT_FALSE (!is_vep))
     {
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("ERROR: vep_idx (%u) is not a vep!", vep_idx);
+      clib_warning ("[%d] ERROR: vep_idx (%u) is not a vep!",
+		    getpid (), vep_idx);
       rv = VPPCOM_EINVAL;
       goto done;
     }
-  if ((VPPCOM_DEBUG > 0) && (PREDICT_FALSE (vep_next_sid == ~0)))
+  if (PREDICT_FALSE (vep_next_sid == ~0))
     {
-      clib_warning ("WARNING: vep_idx (%u) is empty!", vep_idx);
+      if (VPPCOM_DEBUG > 0)
+	clib_warning ("[%d] WARNING: vep_idx (%u) is empty!",
+		      getpid (), vep_idx);
       goto done;
     }
 
@@ -3021,39 +3465,41 @@ vppcom_epoll_wait (uint32_t vep_idx, struct epoll_event *events,
 	  if (PREDICT_FALSE (is_vep))
 	    {
 	      if (VPPCOM_DEBUG > 0)
-		clib_warning ("ERROR: sid (%u) is a vep!", vep_idx);
+		clib_warning ("[%d] ERROR: sid (%u) is a vep!",
+			      getpid (), vep_idx);
 	      rv = VPPCOM_EINVAL;
 	      goto done;
 	    }
 	  if (PREDICT_FALSE (!is_vep_session))
 	    {
 	      if (VPPCOM_DEBUG > 0)
-		clib_warning ("EPOLL_CTL_MOD: session (%u) is not "
-			      "a vep session!", sid);
+		clib_warning ("[%d] ERROR: session (%u) is not "
+			      "a vep session!", getpid (), sid);
 	      rv = VPPCOM_EINVAL;
 	      goto done;
 	    }
 	  if (PREDICT_FALSE (session_vep_idx != vep_idx))
 	    {
-	      clib_warning ("EPOLL_CTL_MOD: session (%u) "
+	      clib_warning ("[%d] ERROR: session (%u) "
 			    "vep_idx (%u) != vep_idx (%u)!",
-			    sid, session->vep.vep_idx, vep_idx);
+			    getpid (), sid, session->vep.vep_idx, vep_idx);
 	      rv = VPPCOM_EINVAL;
 	      goto done;
 	    }
 
 	  add_event = clear_et_mask = 0;
 
-	  if ((EPOLLIN & session_events) && (EPOLLIN & et_mask))
+	  if (EPOLLIN & session_events)
 	    {
 	      VCL_LOCK_AND_GET_SESSION (sid, &session);
 	      ready = vppcom_session_read_ready (session, sid);
 	      clib_spinlock_unlock (&vcm->sessions_lockp);
-	      if (ready > 0)
+	      if ((ready > 0) && (EPOLLIN & et_mask))
 		{
 		  add_event = 1;
 		  events[num_ev].events |= EPOLLIN;
-		  if (EPOLLET & session_events)
+		  if (((EPOLLET | EPOLLIN) & session_events) ==
+		      (EPOLLET | EPOLLIN))
 		    clear_et_mask |= EPOLLIN;
 		}
 	      else if (ready < 0)
@@ -3072,16 +3518,17 @@ vppcom_epoll_wait (uint32_t vep_idx, struct epoll_event *events,
 		}
 	    }
 
-	  if ((EPOLLOUT & session_events) && (EPOLLOUT & et_mask))
+	  if (EPOLLOUT & session_events)
 	    {
 	      VCL_LOCK_AND_GET_SESSION (sid, &session);
 	      ready = vppcom_session_write_ready (session, sid);
 	      clib_spinlock_unlock (&vcm->sessions_lockp);
-	      if (ready > 0)
+	      if ((ready > 0) && (EPOLLOUT & et_mask))
 		{
 		  add_event = 1;
 		  events[num_ev].events |= EPOLLOUT;
-		  if (EPOLLET & session_events)
+		  if (((EPOLLET | EPOLLOUT) & session_events) ==
+		      (EPOLLET | EPOLLOUT))
 		    clear_et_mask |= EPOLLOUT;
 		}
 	      else if (ready < 0)
@@ -3126,8 +3573,10 @@ vppcom_epoll_wait (uint32_t vep_idx, struct epoll_event *events,
 		next_sid = ~0;
 	    }
 	}
+      if (wait_for_time != -1)
+	keep_trying = (clib_time_now (&vcm->clib_time) <= timeout) ? 1 : 0;
     }
-  while ((num_ev == 0) && (clib_time_now (&vcm->clib_time) <= timeout));
+  while ((num_ev == 0) && keep_trying);
 
   if (wait_cont_idx != ~0)
     {
@@ -3143,7 +3592,6 @@ int
 vppcom_session_attr (uint32_t session_index, uint32_t op,
 		     void *buffer, uint32_t * buflen)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   session_t *session;
   int rv = VPPCOM_OK;
   u32 *flags = buffer;
@@ -3154,13 +3602,16 @@ vppcom_session_attr (uint32_t session_index, uint32_t op,
     {
     case VPPCOM_ATTR_GET_NREAD:
       rv = vppcom_session_read_ready (session, session_index);
-      if (VPPCOM_DEBUG > 0)
-	clib_warning ("VPPCOM_ATTR_GET_NREAD: nread = %d", rv);
-
+      if (VPPCOM_DEBUG > 2)
+	clib_warning ("[%d] VPPCOM_ATTR_GET_NREAD: sid %u, nread = %d",
+		      getpid (), rv);
       break;
 
-    case VPPCOM_ATTR_PEEK_NREAD:
-      /* TBD */
+    case VPPCOM_ATTR_GET_NWRITE:
+      rv = vppcom_session_write_ready (session, session_index);
+      if (VPPCOM_DEBUG > 2)
+	clib_warning ("[%d] VPPCOM_ATTR_GET_NWRITE: sid %u, nwrite = %d",
+		      getpid (), session_index, rv);
       break;
 
     case VPPCOM_ATTR_GET_FLAGS:
@@ -3168,10 +3619,10 @@ vppcom_session_attr (uint32_t session_index, uint32_t op,
 	{
 	  *flags = O_RDWR | ((session->is_nonblocking) ? O_NONBLOCK : 0);
 	  *buflen = sizeof (*flags);
-	  if (VPPCOM_DEBUG > 0)
-	    clib_warning ("VPPCOM_ATTR_GET_FLAGS: flags = 0x%08x, "
-			  "is_nonblocking = %u", *flags,
-			  session->is_nonblocking);
+	  if (VPPCOM_DEBUG > 2)
+	    clib_warning ("[%d] VPPCOM_ATTR_GET_FLAGS: sid %u, "
+			  "flags = 0x%08x, is_nonblocking = %u", getpid (),
+			  session_index, *flags, session->is_nonblocking);
 	}
       else
 	rv = VPPCOM_EINVAL;
@@ -3181,9 +3632,10 @@ vppcom_session_attr (uint32_t session_index, uint32_t op,
       if (buffer && buflen && (*buflen >= sizeof (*flags)))
 	{
 	  session->is_nonblocking = (*flags & O_NONBLOCK) ? 1 : 0;
-	  if (VPPCOM_DEBUG > 0)
-	    clib_warning ("VPPCOM_ATTR_SET_FLAGS: flags = 0x%08x, "
-			  "is_nonblocking = %u", *flags,
+	  if (VPPCOM_DEBUG > 2)
+	    clib_warning ("[%d] VPPCOM_ATTR_SET_FLAGS: sid %u, "
+			  "flags = 0x%08x, is_nonblocking = %u",
+			  getpid (), session_index, *flags,
 			  session->is_nonblocking);
 	}
       else
@@ -3203,10 +3655,10 @@ vppcom_session_attr (uint32_t session_index, uint32_t op,
 	    clib_memcpy (ep->ip, &session->peer_addr.ip46.ip6,
 			 sizeof (ip6_address_t));
 	  *buflen = sizeof (*ep);
-	  if (VPPCOM_DEBUG > 0)
-	    clib_warning ("VPPCOM_ATTR_GET_PEER_ADDR: sid %u is_ip4 = %u, "
-			  "addr = %U, port %u", session_index,
-			  ep->is_ip4, format_ip46_address,
+	  if (VPPCOM_DEBUG > 1)
+	    clib_warning ("[%d] VPPCOM_ATTR_GET_PEER_ADDR: sid %u, is_ip4 = "
+			  "%u, addr = %U, port %u", getpid (),
+			  session_index, ep->is_ip4, format_ip46_address,
 			  &session->peer_addr.ip46, ep->is_ip4,
 			  clib_net_to_host_u16 (ep->port));
 	}
@@ -3227,10 +3679,10 @@ vppcom_session_attr (uint32_t session_index, uint32_t op,
 	    clib_memcpy (ep->ip, &session->lcl_addr.ip46.ip6,
 			 sizeof (ip6_address_t));
 	  *buflen = sizeof (*ep);
-	  if (VPPCOM_DEBUG > 0)
-	    clib_warning ("VPPCOM_ATTR_GET_LCL_ADDR: sid %u is_ip4 = %u, "
-			  "addr = %U port %d", session_index,
-			  ep->is_ip4, format_ip46_address,
+	  if (VPPCOM_DEBUG > 1)
+	    clib_warning ("[%d] VPPCOM_ATTR_GET_LCL_ADDR: sid %u, is_ip4 = "
+			  "%u, addr = %U port %d", getpid (),
+			  session_index, ep->is_ip4, format_ip46_address,
 			  &session->lcl_addr.ip46, ep->is_ip4,
 			  clib_net_to_host_u16 (ep->port));
 	}
@@ -3270,7 +3722,6 @@ int
 vppcom_session_recvfrom (uint32_t session_index, void *buffer,
 			 uint32_t buflen, int flags, vppcom_endpt_t * ep)
 {
-  vppcom_main_t *vcm = &vppcom_main;
   int rv = VPPCOM_OK;
   session_t *session = 0;
 
@@ -3283,8 +3734,10 @@ vppcom_session_recvfrom (uint32_t session_index, void *buffer,
 	  clib_spinlock_unlock (&vcm->sessions_lockp);
 	  if (VPPCOM_DEBUG > 0)
 	    clib_warning ("[%d] invalid session, sid (%u) has been closed!",
-			  vcm->my_pid, session_index);
-	  rv = VPPCOM_EINVAL;
+			  getpid (), session_index);
+	  rv = VPPCOM_EBADFD;
+	  clib_spinlock_unlock (&vcm->sessions_lockp);
+	  goto done;
 	}
       ep->vrf = session->vrf;
       ep->is_ip4 = session->peer_addr.is_ip4;
@@ -3296,22 +3749,19 @@ vppcom_session_recvfrom (uint32_t session_index, void *buffer,
 	clib_memcpy (ep->ip, &session->peer_addr.ip46.ip6,
 		     sizeof (ip6_address_t));
       clib_spinlock_unlock (&vcm->sessions_lockp);
-      rv = vppcom_session_read (session_index, buffer, buflen);
     }
-  else if (flags == 0)
+
+  if (flags == 0)
     rv = vppcom_session_read (session_index, buffer, buflen);
   else if (flags & MSG_PEEK)
-    {
-      rv = vppcom_session_attr (session_index, VPPCOM_ATTR_GET_NREAD, 0, 0);
-      if (rv > buflen)
-	rv = buflen;
-    }
+    rv = vppcom_session_peek (session_index, buffer, buflen);
   else
     {
-      clib_warning ("Unsupport flags for recvfro %d", flags);
+      clib_warning ("[%d] Unsupport flags for recvfrom %d", getpid (), flags);
       rv = VPPCOM_EAFNOSUPPORT;
     }
 
+done:
   return rv;
 }
 
@@ -3319,16 +3769,24 @@ int
 vppcom_session_sendto (uint32_t session_index, void *buffer,
 		       uint32_t buflen, int flags, vppcom_endpt_t * ep)
 {
+  if (!buffer)
+    return VPPCOM_EINVAL;
+
   if (ep)
-    // TBD
-    return -1;
-  else if (flags == 0)
-    return (vppcom_session_write (session_index, buffer, buflen));
-  else if (flags)
-    // TBD check the flags and do the right thing
-    return (vppcom_session_write (session_index, buffer, buflen));
-
-  return -1;
+    {
+      // TBD
+      return VPPCOM_EINVAL;
+    }
+
+  if (flags)
+    {
+      // TBD check the flags and do the right thing
+      if (VPPCOM_DEBUG > 2)
+	clib_warning ("[%d] handling flags 0x%u (%d) not implemented yet.",
+		      getpid (), flags, flags);
+    }
+
+  return (vppcom_session_write (session_index, buffer, buflen));
 }
 
 /*