src/vcl/vppcom.c - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2017 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this
  * You may obtain a copy of the License at:
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <signal.h>
 #include <svm/svm_fifo_segment.h>
 #include <vlibmemory/api.h>
 #include <vpp/api/vpe_msg_enum.h>
 #include <vnet/session/application_interface.h>
 #include <vcl/vppcom.h>
 #include <vlib/unix/unix.h>
 #include <vppinfra/vec_bootstrap.h>
 #include <vppinfra/elog.h>

 #define vl_typedefs		/* define message structures */
 #include <vpp/api/vpe_all_api_h.h>
 #undef vl_typedefs

 /* declare message handlers for each api */

 #define vl_endianfun		/* define message structures */
 #include <vpp/api/vpe_all_api_h.h>
 #undef vl_endianfun

 /* instantiate all the print functions we know about */
 #define vl_print(handle, ...)
 #define vl_printfun
 #include <vpp/api/vpe_all_api_h.h>
 #undef vl_printfun

 #if (CLIB_DEBUG > 0)
 /* 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_INIT 0
 #endif

 #define VPPCOM_DEBUG vcm->debug

 /*
  * VPPCOM Private definitions and functions.
  */
 typedef enum
 {
   STATE_APP_START,
   STATE_APP_CONN_VPP,
   STATE_APP_ENABLED,
   STATE_APP_ATTACHED,
 } app_state_t;

 typedef enum
 {
   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
 {
   u32 next_sid;
   u32 prev_sid;
   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;

 typedef struct
 {
   u8 is_ip4;
   ip46_address_t ip46;
 } vppcom_ip46_t;

 enum
 {
   VCL_SESS_ATTR_SERVER,
   VCL_SESS_ATTR_CUT_THRU,
   VCL_SESS_ATTR_VEP,
   VCL_SESS_ATTR_VEP_SESSION,
   VCL_SESS_ATTR_LISTEN,		// SOL_SOCKET,SO_ACCEPTCONN
   VCL_SESS_ATTR_NONBLOCK,	// fcntl,O_NONBLOCK
   VCL_SESS_ATTR_REUSEADDR,	// SOL_SOCKET,SO_REUSEADDR
   VCL_SESS_ATTR_REUSEPORT,	// SOL_SOCKET,SO_REUSEPORT
   VCL_SESS_ATTR_BROADCAST,	// SOL_SOCKET,SO_BROADCAST
   VCL_SESS_ATTR_V6ONLY,		// SOL_TCP,IPV6_V6ONLY
   VCL_SESS_ATTR_KEEPALIVE,	// SOL_SOCKET,SO_KEEPALIVE
   VCL_SESS_ATTR_TCP_NODELAY,	// SOL_TCP,TCP_NODELAY
   VCL_SESS_ATTR_TCP_KEEPIDLE,	// SOL_TCP,TCP_KEEPIDLE
   VCL_SESS_ATTR_TCP_KEEPINTVL,	// SOL_TCP,TCP_KEEPINTVL
   VCL_SESS_ATTR_MAX
 } vppcom_session_attr_t;

 #define VCL_SESS_ATTR_SET(ATTR, VAL)            \
 do {                                            \
   (ATTR) |= 1 << (VAL);                         \
  } while (0)

 #define VCL_SESS_ATTR_CLR(ATTR, VAL)            \
 do {                                            \
   (ATTR) &= ~(1 << (VAL));                      \
  } while (0)

 #define VCL_SESS_ATTR_TEST(ATTR, VAL)           \
   ((ATTR) & (1 << (VAL)) ? 1 : 0)

 typedef struct
 {
   volatile session_state_t state;

   svm_fifo_t *rx_fifo;
   svm_fifo_t *tx_fifo;
   u32 sndbuf_size;		// VPP-TBD: Hack until support setsockopt(SO_SNDBUF)
   u32 rcvbuf_size;		// VPP-TBD: Hack until support setsockopt(SO_RCVBUF)
   u32 user_mss;			// VPP-TBD: Hack until support setsockopt(TCP_MAXSEG)
   u8 *segment_name;
   u32 sm_seg_index;
   u32 client_context;
   u64 vpp_handle;
   svm_queue_t *vpp_event_queue;

   /* Socket configuration state */
   u8 is_vep;
   u8 is_vep_session;
   u32 attr;
   u32 wait_cont_idx;
   vppcom_epoll_t vep;
   int libc_epfd;
   vppcom_ip46_t lcl_addr;
   vppcom_ip46_t peer_addr;
   u16 lcl_port;			// network order
   u16 peer_port;		// network order
   u8 proto;
   u64 client_queue_address;
   u64 options[16];
   elog_track_t elog_track;
 } session_t;

 typedef struct vppcom_cfg_t_
 {
   u64 heapsize;
   u32 vpp_api_q_length;
   u64 segment_baseva;
   u32 segment_size;
   u32 add_segment_size;
   u32 preallocated_fifo_pairs;
   u32 rx_fifo_size;
   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;
   u32 event_ring_size;
   char *event_log_path;
   u8 *vpp_api_filename;
 } vppcom_cfg_t;

 typedef struct vppcom_main_t_
 {
   u8 init;
   u32 debug;
   u32 *client_session_index_fifo;
   int main_cpu;

   /* vpp input queue */
   svm_queue_t *vl_input_queue;

   /* API client handle */
   u32 my_client_index;

   /* Session pool */
   clib_spinlock_t sessions_lockp;
   session_t *sessions;

   /* Hash table for disconnect processing */
   uword *session_index_by_vpp_handles;

   /* Select bitmaps */
   clib_bitmap_t *rd_bitmap;
   clib_bitmap_t *wr_bitmap;
   clib_bitmap_t *ex_bitmap;

   /* Our event queue */
   svm_queue_t *app_event_queue;

   /* unique segment name counter */
   u32 unique_segment_index;

   /* For deadman timers */
   clib_time_t clib_time;

   /* State of the connection, shared between msg RX thread and main thread */
   volatile app_state_t app_state;

   vppcom_cfg_t cfg;

   /* Event logging */
   elog_main_t elog_main;
   elog_track_t elog_track;

   /* VNET_API_ERROR_FOO -> "Foo" hash table */
   uword *error_string_by_error_number;
 } vppcom_main_t;

 /* 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 ("VCL<%d>: ERROR: Invalid ##I (%u)!",        \
                     getpid (), I);                              \
       goto done;                                                \
     }                                                           \
 } while (0)

 static const char *
 vppcom_app_state_str (app_state_t state)
 {
   char *st;

   switch (state)
     {
     case STATE_APP_START:
       st = "STATE_APP_START";
       break;

     case STATE_APP_CONN_VPP:
       st = "STATE_APP_CONN_VPP";
       break;

     case STATE_APP_ENABLED:
       st = "STATE_APP_ENABLED";
       break;

     case STATE_APP_ATTACHED:
       st = "STATE_APP_ATTACHED";
       break;

     default:
       st = "UNKNOWN_APP_STATE";
       break;
     }

   return st;
 }

 static const char *
 vppcom_session_state_str (session_state_t state)
 {
   char *st;

   switch (state)
     {
     case STATE_START:
       st = "STATE_START";
       break;

     case STATE_CONNECT:
       st = "STATE_CONNECT";
       break;

     case STATE_LISTEN:
       st = "STATE_LISTEN";
       break;

     case STATE_ACCEPT:
       st = "STATE_ACCEPT";
       break;

     case STATE_CLOSE_ON_EMPTY:
       st = "STATE_CLOSE_ON_EMPTY";
       break;

     case STATE_DISCONNECT:
       st = "STATE_DISCONNECT";
       break;

     case STATE_FAILED:
       st = "STATE_FAILED";
       break;

     default:
       st = "UNKNOWN_STATE";
       break;
     }

   return st;
 }

 /*
  * VPPCOM Utility Functions
  */
 static inline int
 vppcom_session_at_index (u32 session_index, session_t * volatile *sess)
 {
   /* 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 ("VCL<%d>: invalid session, sid (%u) has been closed!",
 		    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 ("VCL<%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 ("VCL<%d>: invalid listen session, sid (%u)",
 		      getpid (), p[0]);
       return 0;
     }

   session = pool_elt_at_index (vcm->sessions, p[0]);
   ASSERT (session->state & STATE_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 void
 write_elog (void)
 {
   elog_main_t *em = &vcm->elog_main;
   char *chroot_file;
   clib_error_t *error = 0;

   chroot_file =
     (char *) format (0, "%s/%d-%d-vcl-elog%c", vcm->cfg.event_log_path,
 		     vcm->my_client_index, getpid (), 0);
   error = elog_write_file (em, chroot_file, 1 /* flush ring */ );
   if (error)
     {
       clib_error_report (error);
     }
   if (VPPCOM_DEBUG > 0)
     clib_warning ("[%d] Event Log:'%s' ", getpid (), chroot_file);

 }

 static int
 vppcom_connect_to_vpp (char *app_name)
 {
   api_main_t *am = &api_main;
   vppcom_cfg_t *vcl_cfg = &vcm->cfg;
   int rv = VPPCOM_OK;

   if (!vcl_cfg->vpp_api_filename)
     vcl_cfg->vpp_api_filename = format (0, "/vpe-api%c", 0);

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: app (%s) connecting to VPP api (%s)...",
 		  getpid (), app_name, vcl_cfg->vpp_api_filename);

   if (vl_client_connect_to_vlib ((char *) vcl_cfg->vpp_api_filename, app_name,
 				 vcm->cfg.vpp_api_q_length) < 0)
     {
       clib_warning ("VCL<%d>: app (%s) connect failed!", getpid (), app_name);
       rv = VPPCOM_ECONNREFUSED;
     }
   else
     {
       vcm->vl_input_queue = am->shmem_hdr->vl_input_queue;
       vcm->my_client_index = am->my_client_index;
       vcm->app_state = STATE_APP_CONN_VPP;

       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: app (%s) is connected to VPP!",
 		      getpid (), app_name);
     }

   if (VPPCOM_DEBUG > 0)
     {
       vcm->elog_main.lock =
 	clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
       vcm->elog_main.lock[0] = 0;
       vcm->elog_main.event_ring_size = vcm->cfg.event_ring_size;
       elog_init (&vcm->elog_main, vcm->elog_main.event_ring_size);
       elog_enable_disable (&vcm->elog_main, 1);

       vcm->elog_track.name =
 	(char *) format (0, "P:%d:C:%d%c", getpid (),
 			 vcm->my_client_index, 0);
       elog_track_register (&vcm->elog_main, &vcm->elog_track);

       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
       {
 	.format = "connect_vpp:rv:%d",
 	.format_args = "i4",
       };
       struct
       {
 	u32 data;
       } *ed;
       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, vcm->elog_track);
       ed->data = rv;
       /* *INDENT-ON* */
     }
   return rv;
 }

 static u8 *
 format_api_error (u8 * s, va_list * args)
 {
   i32 error = va_arg (*args, u32);
   uword *p;

   p = hash_get (vcm->error_string_by_error_number, -error);

   if (p)
     s = format (s, "%s (%d)", p[0], error);
   else
     s = format (s, "%d", error);
   return s;
 }

 static void
 vppcom_init_error_string_table (void)
 {
   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);
   foreach_vnet_api_error;
 #undef _

   hash_set (vcm->error_string_by_error_number, 99, "Misc");
 }

 static inline int
 vppcom_wait_for_app_state_change (app_state_t app_state)
 {
   f64 timeout = clib_time_now (&vcm->clib_time) + vcm->cfg.app_timeout;

   while (clib_time_now (&vcm->clib_time) < timeout)
     {
       if (vcm->app_state == app_state)
 	return VPPCOM_OK;
     }
   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: timeout waiting for state %s (%d)", getpid (),
 		  vppcom_app_state_str (app_state), app_state);

   if (VPPCOM_DEBUG > 0)
     {
       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
 	{
 	  .format = "ERR: timeout state:%d",
 	  .format_args = "i4",
 	};
       struct
       {
 	u32 data;
       } *ed;

       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, vcm->elog_track);

       ed->data = app_state;
       /* *INDENT-ON* */
     }

   return VPPCOM_ETIMEDOUT;
 }

 static inline int
 vppcom_wait_for_session_state_change (u32 session_index,
 				      session_state_t state,
 				      f64 wait_for_time)
 {
   f64 timeout = clib_time_now (&vcm->clib_time) + wait_for_time;
   session_t *volatile session;
   int rv;

   do
     {
       clib_spinlock_lock (&vcm->sessions_lockp);
       rv = vppcom_session_at_index (session_index, &session);
       if (PREDICT_FALSE (rv))
 	{
 	  clib_spinlock_unlock (&vcm->sessions_lockp);
 	  return rv;
 	}
       if (session->state & state)
 	{
 	  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 ("VCL<%d>: timeout waiting for state 0x%x (%s)", getpid (),
 		  state, vppcom_session_state_str (state));

   if (VPPCOM_DEBUG > 0)
     {
       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
 	{
 	  .format = "ERR: timeout state:%d",
 	  .format_args = "i4",
 	};
       struct
       {
 	u32 data;
       } *ed;

       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

       ed->data = state;
       /* *INDENT-ON* */
     }

   return VPPCOM_ETIMEDOUT;
 }

 static inline int
 vppcom_wait_for_client_session_index (f64 wait_for_time)
 {
   f64 timeout = clib_time_now (&vcm->clib_time) + wait_for_time;

   do
     {
       if (clib_fifo_elts (vcm->client_session_index_fifo))
 	return VPPCOM_OK;
     }
   while (clib_time_now (&vcm->clib_time) < timeout);

   if (wait_for_time == 0)
     return VPPCOM_EAGAIN;

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: timeout waiting for client_session_index",
 		  getpid ());

   if (VPPCOM_DEBUG > 0)
     {
       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
 	{
 	  .format = "ERR: timeout waiting for session index :%d",
 	  .format_args = "i4",
 	};
       struct
       {
 	u32 data;
       } *ed;

       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, vcm->elog_track);

       ed->data = getpid();
       /* *INDENT-ON* */
     }

   return VPPCOM_ETIMEDOUT;
 }

 /*
  * VPP-API message functions
  */
 static void
 vppcom_send_session_enable_disable (u8 is_enable)
 {
   vl_api_session_enable_disable_t *bmp;
   bmp = vl_msg_api_alloc (sizeof (*bmp));
   memset (bmp, 0, sizeof (*bmp));

   bmp->_vl_msg_id = ntohs (VL_API_SESSION_ENABLE_DISABLE);
   bmp->client_index = vcm->my_client_index;
   bmp->context = htonl (0xfeedface);
   bmp->is_enable = is_enable;
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & bmp);
 }

 static int
 vppcom_app_session_enable (void)
 {
   int rv;

   if (vcm->app_state != STATE_APP_ENABLED)
     {
       vppcom_send_session_enable_disable (1 /* is_enabled == TRUE */ );
       rv = vppcom_wait_for_app_state_change (STATE_APP_ENABLED);
       if (PREDICT_FALSE (rv))
 	{
 	  if (VPPCOM_DEBUG > 0)
 	    clib_warning ("VCL<%d>: application session enable timed out! "
 			  "returning %d (%s)",
 			  getpid (), rv, vppcom_retval_str (rv));
 	  return rv;
 	}
     }
   return VPPCOM_OK;
 }

 static void
   vl_api_session_enable_disable_reply_t_handler
   (vl_api_session_enable_disable_reply_t * mp)
 {
   if (mp->retval)
     {
       clib_warning ("VCL<%d>: session_enable_disable failed: %U", getpid (),
 		    format_api_error, ntohl (mp->retval));
     }
   else
     vcm->app_state = STATE_APP_ENABLED;
 }

 static void
 vppcom_app_send_attach (void)
 {
   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));

   bmp->_vl_msg_id = ntohs (VL_API_APPLICATION_ATTACH);
   bmp->client_index = vcm->my_client_index;
   bmp->context = htonl (0xfeedface);
   bmp->options[APP_OPTIONS_FLAGS] =
     APP_OPTIONS_FLAGS_ACCEPT_REDIRECT | APP_OPTIONS_FLAGS_ADD_SEGMENT |
     (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[APP_OPTIONS_SEGMENT_SIZE] = vcm->cfg.segment_size;
   bmp->options[APP_OPTIONS_ADD_SEGMENT_SIZE] = vcm->cfg.add_segment_size;
   bmp->options[APP_OPTIONS_RX_FIFO_SIZE] = vcm->cfg.rx_fifo_size;
   bmp->options[APP_OPTIONS_TX_FIFO_SIZE] = vcm->cfg.tx_fifo_size;
   bmp->options[APP_OPTIONS_PREALLOC_FIFO_PAIRS] =
     vcm->cfg.preallocated_fifo_pairs;
   bmp->options[APP_OPTIONS_EVT_QUEUE_SIZE] = vcm->cfg.event_queue_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)
 {
   int rv;

   vppcom_app_send_attach ();
   rv = vppcom_wait_for_app_state_change (STATE_APP_ATTACHED);
   if (PREDICT_FALSE (rv))
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: application attach timed out! "
 		      "returning %d (%s)",
 		      getpid (), rv, vppcom_retval_str (rv));
       return rv;
     }
   return VPPCOM_OK;
 }

 static void
 vppcom_app_detach (void)
 {
   vl_api_application_detach_t *bmp;
   bmp = vl_msg_api_alloc (sizeof (*bmp));
   memset (bmp, 0, sizeof (*bmp));

   bmp->_vl_msg_id = ntohs (VL_API_APPLICATION_DETACH);
   bmp->client_index = vcm->my_client_index;
   bmp->context = htonl (0xfeedface);
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & bmp);
 }

 static void
 vl_api_application_attach_reply_t_handler (vl_api_application_attach_reply_t *
 					   mp)
 {
   static svm_fifo_segment_create_args_t _a;
   svm_fifo_segment_create_args_t *a = &_a;
   int rv;

   memset (a, 0, sizeof (*a));
   if (mp->retval)
     {
       clib_warning ("VCL<%d>: attach failed: %U", getpid (),
 		    format_api_error, ntohl (mp->retval));
       return;
     }

   if (mp->segment_name_length == 0)
     {
       clib_warning ("VCL<%d>: segment_name_length zero", getpid ());
       return;
     }

   a->segment_name = (char *) mp->segment_name;
   a->segment_size = mp->segment_size;

   ASSERT (mp->app_event_queue_address);

   /* Attach to the segment vpp created */
   rv = svm_fifo_segment_attach (a);
   vec_reset_length (a->new_segment_indices);
   if (PREDICT_FALSE (rv))
     {
       clib_warning ("VCL<%d>: svm_fifo_segment_attach ('%s') failed",
 		    getpid (), mp->segment_name);
       return;
     }

   vcm->app_event_queue =
     uword_to_pointer (mp->app_event_queue_address, svm_queue_t *);

   vcm->app_state = STATE_APP_ATTACHED;
 }

 static void
 vl_api_application_detach_reply_t_handler (vl_api_application_detach_reply_t *
 					   mp)
 {
   if (mp->retval)
     clib_warning ("VCL<%d>: detach failed: %U", getpid (), format_api_error,
 		  ntohl (mp->retval));

   vcm->app_state = STATE_APP_ENABLED;
 }

 static void
 vl_api_disconnect_session_reply_t_handler (vl_api_disconnect_session_reply_t *
 					   mp)
 {
   if (mp->retval)
     clib_warning ("VCL<%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)
 {
   static svm_fifo_segment_create_args_t _a;
   svm_fifo_segment_create_args_t *a = &_a;
   int rv;

   memset (a, 0, sizeof (*a));
   a->segment_name = (char *) mp->segment_name;
   a->segment_size = mp->segment_size;
   /* Attach to the segment vpp created */
   rv = svm_fifo_segment_attach (a);
   vec_reset_length (a->new_segment_indices);
   if (PREDICT_FALSE (rv))
     {
       clib_warning ("VCL<%d>: svm_fifo_segment_attach ('%s') failed",
 		    getpid (), mp->segment_name);
       return;
     }
   if (VPPCOM_DEBUG > 1)
     clib_warning ("VCL<%d>: mapped new segment '%s' size %d", getpid (),
 		  mp->segment_name, mp->segment_size);
 }

 static void
 vl_api_unmap_segment_t_handler (vl_api_unmap_segment_t * mp)
 {

 /*
  * XXX Need segment_name to session_id hash,
  * XXX - have sessionID by handle hash currently
  */
   clib_warning ("Unmapped segment '%s'", mp->segment_name);
 }

 static void
 vl_api_disconnect_session_t_handler (vl_api_disconnect_session_t * mp)
 {
   uword *p;

   p = hash_get (vcm->session_index_by_vpp_handles, mp->handle);
   if (p)
     {
       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 ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		      "setting state to 0x%x (%s)",
 		      getpid (), mp->handle, session_index, session->state,
 		      vppcom_session_state_str (session->state));
       clib_spinlock_unlock (&vcm->sessions_lockp);
       return;

     done:
       if (VPPCOM_DEBUG > 1)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		      "session lookup failed!",
 		      getpid (), mp->handle, session_index);
     }
   else
     clib_warning ("VCL<%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)
 {
   session_t *session = 0;
   vl_api_reset_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))
 	{
 	  rv = VNET_API_ERROR_INVALID_VALUE_2;
 	  clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 			"session lookup failed! returning %d %U",
 			getpid (), mp->handle, p[0],
 			rv, format_api_error, rv);
 	}
       else
 	{
 	  /* TBD: should this disconnect immediately and
 	   * flush the fifos?
 	   */
 	  session->state = STATE_CLOSE_ON_EMPTY;

 	  if (VPPCOM_DEBUG > 1)
 	    clib_warning ("VCL<%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);
     }
   else
     {
       rv = VNET_API_ERROR_INVALID_VALUE;
       clib_warning ("VCL<%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));
   memset (rmp, 0, sizeof (*rmp));
   rmp->_vl_msg_id = ntohs (VL_API_RESET_SESSION_REPLY);
   rmp->retval = htonl (rv);
   rmp->handle = mp->handle;
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & rmp);
 }

 static void
 vl_api_connect_session_reply_t_handler (vl_api_connect_session_reply_t * mp)
 {
   session_t *session = 0;
   u32 session_index;
   svm_fifo_t *rx_fifo, *tx_fifo;
   int rv = VPPCOM_OK;

   session_index = mp->context;
   VCL_LOCK_AND_GET_SESSION (session_index, &session);
 done:
   if (mp->retval)
     {
       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 		    "connect failed! %U",
 		    getpid (), mp->handle, session_index,
 		    format_api_error, ntohl (mp->retval));
       if (session)
 	{
 	  session->state = STATE_FAILED;
 	  session->vpp_handle = mp->handle;
 	}
       else
 	{
 	  clib_warning ("[%s] ERROR: vpp handle 0x%llx, sid %u: "
 			"Invalid session index (%u)!",
 			getpid (), mp->handle, session_index);
 	}
       goto done_unlock;
     }

   if (rv)
     goto done_unlock;

   /*
    * Setup session
    */
   session->vpp_event_queue = uword_to_pointer (mp->vpp_event_queue_address,
 					       svm_queue_t *);

   rx_fifo = uword_to_pointer (mp->server_rx_fifo, svm_fifo_t *);
   rx_fifo->client_session_index = session_index;
   tx_fifo = uword_to_pointer (mp->server_tx_fifo, svm_fifo_t *);
   tx_fifo->client_session_index = session_index;

   session->rx_fifo = rx_fifo;
   session->tx_fifo = tx_fifo;
   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 ("VCL<%d>: vpp handle 0x%llx, sid %u: connect succeeded!"
 		  " session_rx_fifo %p, refcnt %d,"
 		  " session_tx_fifo %p, refcnt %d",
 		  getpid (), mp->handle, session_index,
 		  session->rx_fifo,
 		  session->rx_fifo->refcnt,
 		  session->tx_fifo, session->tx_fifo->refcnt);
 done_unlock:
   clib_spinlock_unlock (&vcm->sessions_lockp);
 }

 static void
 vppcom_send_connect_sock (session_t * session, u32 session_index)
 {
   vl_api_connect_sock_t *cmp;

   /* Assumes caller as acquired the spinlock: vcm->sessions_lockp */
   cmp = vl_msg_api_alloc (sizeof (*cmp));
   memset (cmp, 0, sizeof (*cmp));
   cmp->_vl_msg_id = ntohs (VL_API_CONNECT_SOCK);
   cmp->client_index = vcm->my_client_index;
   cmp->context = session_index;

   cmp->is_ip4 = session->peer_addr.is_ip4;
   clib_memcpy (cmp->ip, &session->peer_addr.ip46, sizeof (cmp->ip));
   cmp->port = session->peer_port;
   cmp->proto = session->proto;
   clib_memcpy (cmp->options, session->options, sizeof (cmp->options));
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & cmp);
 }

 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 ("VCL<%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)
 {
   vl_api_disconnect_session_t *dmp;

   if (VPPCOM_DEBUG > 1)
     clib_warning ("VCL<%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 = vpp_handle;
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & dmp);
 }

 static void
 vl_api_bind_sock_reply_t_handler (vl_api_bind_sock_reply_t * mp)
 {
   session_t *session = 0;
   u32 session_index = mp->context;
   int rv;

   VCL_LOCK_AND_GET_SESSION (session_index, &session);
 done:
   if (mp->retval)
     {
       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, "
 		    "sid %u: bind failed: %U",
 		    getpid (), mp->handle, session_index,
 		    format_api_error, ntohl (mp->retval));
       rv = vppcom_session_at_index (session_index, &session);
       if (rv == VPPCOM_OK)
 	{
 	  session->state = STATE_FAILED;
 	  session->vpp_handle = mp->handle;
 	}
       else
 	{
 	  clib_warning ("[%s] ERROR: vpp handle 0x%llx, sid %u: "
 			"Invalid session index (%u)!",
 			getpid (), mp->handle, session_index);
 	}
       goto done_unlock;
     }

   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->state = STATE_LISTEN;

   if (VPPCOM_DEBUG > 1)
     clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: bind succeeded!",
 		  getpid (), mp->handle, mp->context);
 done_unlock:
   clib_spinlock_unlock (&vcm->sessions_lockp);
 }

 static void
 vl_api_unbind_sock_reply_t_handler (vl_api_unbind_sock_reply_t * mp)
 {
   if (mp->retval)
     clib_warning ("VCL<%d>: ERROR: sid %u: unbind failed: %U",
 		  getpid (), mp->context, format_api_error,
 		  ntohl (mp->retval));

   else if (VPPCOM_DEBUG > 1)
     clib_warning ("VCL<%d>: sid %u: unbind succeeded!",
 		  getpid (), mp->context);
 }

 u8 *
 format_ip4_address (u8 * s, va_list * args)
 {
   u8 *a = va_arg (*args, u8 *);
   return format (s, "%d.%d.%d.%d", a[0], a[1], a[2], a[3]);
 }

 u8 *
 format_ip6_address (u8 * s, va_list * args)
 {
   ip6_address_t *a = va_arg (*args, ip6_address_t *);
   u32 i, i_max_n_zero, max_n_zeros, i_first_zero, n_zeros, last_double_colon;

   i_max_n_zero = ARRAY_LEN (a->as_u16);
   max_n_zeros = 0;
   i_first_zero = i_max_n_zero;
   n_zeros = 0;
   for (i = 0; i < ARRAY_LEN (a->as_u16); i++)
     {
       u32 is_zero = a->as_u16[i] == 0;
       if (is_zero && i_first_zero >= ARRAY_LEN (a->as_u16))
 	{
 	  i_first_zero = i;
 	  n_zeros = 0;
 	}
       n_zeros += is_zero;
       if ((!is_zero && n_zeros > max_n_zeros)
 	  || (i + 1 >= ARRAY_LEN (a->as_u16) && n_zeros > max_n_zeros))
 	{
 	  i_max_n_zero = i_first_zero;
 	  max_n_zeros = n_zeros;
 	  i_first_zero = ARRAY_LEN (a->as_u16);
 	  n_zeros = 0;
 	}
     }

   last_double_colon = 0;
   for (i = 0; i < ARRAY_LEN (a->as_u16); i++)
     {
       if (i == i_max_n_zero && max_n_zeros > 1)
 	{
 	  s = format (s, "::");
 	  i += max_n_zeros - 1;
 	  last_double_colon = 1;
 	}
       else
 	{
 	  s = format (s, "%s%x",
 		      (last_double_colon || i == 0) ? "" : ":",
 		      clib_net_to_host_u16 (a->as_u16[i]));
 	  last_double_colon = 0;
 	}
     }

   return s;
 }

 /* Format an IP46 address. */
 u8 *
 format_ip46_address (u8 * s, va_list * args)
 {
   ip46_address_t *ip46 = va_arg (*args, ip46_address_t *);
   ip46_type_t type = va_arg (*args, ip46_type_t);
   int is_ip4 = 1;

   switch (type)
     {
     case IP46_TYPE_ANY:
       is_ip4 = ip46_address_is_ip4 (ip46);
       break;
     case IP46_TYPE_IP4:
       is_ip4 = 1;
       break;
     case IP46_TYPE_IP6:
       is_ip4 = 0;
       break;
     }

   return is_ip4 ?
     format (s, "%U", format_ip4_address, &ip46->ip4) :
     format (s, "%U", format_ip6_address, &ip46->ip6);
 }

 static inline void
 vppcom_send_accept_session_reply (u64 handle, u32 context, 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->context = context;
   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)
 {
   svm_fifo_t *rx_fifo, *tx_fifo;
   session_t *session, *listen_session;
   u32 session_index;

   clib_spinlock_lock (&vcm->sessions_lockp);
   if (!clib_fifo_free_elts (vcm->client_session_index_fifo))
     {
       clib_warning ("VCL<%d>: client session queue is full!", getpid ());
       vppcom_send_accept_session_reply (mp->handle, mp->context,
 					VNET_API_ERROR_QUEUE_FULL);
       clib_spinlock_unlock (&vcm->sessions_lockp);
       return;
     }

   listen_session = vppcom_session_table_lookup_listener (mp->listener_handle);
   if (!listen_session)
     {
       clib_warning ("VCL<%d>: ERROR: couldn't find listen session: "
 		    "unknown vpp listener handle %llx",
 		    getpid (), mp->listener_handle);
       clib_spinlock_unlock (&vcm->sessions_lockp);
       return;
     }

   /* Allocate local session and set it up */
   pool_get (vcm->sessions, session);
   memset (session, 0, sizeof (*session));
   session_index = session - vcm->sessions;

   rx_fifo = uword_to_pointer (mp->server_rx_fifo, svm_fifo_t *);
   rx_fifo->client_session_index = session_index;
   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->client_context = mp->context;
   session->rx_fifo = rx_fifo;
   session->tx_fifo = tx_fifo;
   session->vpp_event_queue = uword_to_pointer (mp->vpp_event_queue_address,
 					       svm_queue_t *);
   session->state = STATE_ACCEPT;
   session->peer_port = mp->port;
   session->peer_addr.is_ip4 = mp->is_ip4;
   clib_memcpy (&session->peer_addr.ip46, mp->ip,
 	       sizeof (session->peer_addr.ip46));

   /* 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);

   if (VPPCOM_DEBUG > 1)
     clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: client accept "
 		  "request from %s address %U port %d queue %p!", getpid (),
 		  mp->handle, session_index, mp->is_ip4 ? "IPv4" : "IPv6",
 		  format_ip46_address, &mp->ip, mp->is_ip4,
 		  clib_net_to_host_u16 (mp->port), session->vpp_event_queue);

   if (VPPCOM_DEBUG > 0)
     {
       session->elog_track.name =
 	(char *) format (0, "C:%d:S:%d%c", vcm->my_client_index,
 			 session_index, 0);
       elog_track_register (&vcm->elog_main, &session->elog_track);

       if (session->peer_addr.is_ip4)
 	{
           /* *INDENT-OFF* */
 	  ELOG_TYPE_DECLARE (e) =
 	  {
 	    .format =
 	    "client_accept:handle:%x addr:%d.%d.%d.%d:%d",
 	    .format_args = "i8i1i1i1i1i2",
 	  };

 	  CLIB_PACKED (struct {
 	    u64 handle;	//8
 	    u8 addr[4];	//4
 	    u16 port;	//2
 	  }) * ed;

 	  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 	  ed->handle = mp->handle;
 	  ed->addr[0] = session->peer_addr.ip46.ip4.as_u8[0];
 	  ed->addr[1] = session->peer_addr.ip46.ip4.as_u8[1];
 	  ed->addr[2] = session->peer_addr.ip46.ip4.as_u8[2];
 	  ed->addr[3] = session->peer_addr.ip46.ip4.as_u8[3];
 	  ed->port = clib_net_to_host_u16 (session->peer_port);
 	  /* *INDENT-ON* */
 	}
       else
 	{
 	  clib_warning ("ip6");
 	}
     }
   clib_spinlock_unlock (&vcm->sessions_lockp);

 }

 static void
 vppcom_send_connect_session_reply (session_t * session, u32 session_index,
 				   u64 vpp_handle, u32 context, int retval)
 {
   vl_api_connect_session_reply_t *rmp;
   u32 len;
   svm_queue_t *client_q;

   rmp = vl_msg_api_alloc (sizeof (*rmp));
   memset (rmp, 0, sizeof (*rmp));
   rmp->_vl_msg_id = ntohs (VL_API_CONNECT_SESSION_REPLY);

   if (!session)
     {
       rmp->context = context;
       rmp->handle = vpp_handle;
       rmp->retval = htonl (retval);
       vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & rmp);
       return;
     }

   rmp->context = session->client_context;
   rmp->retval = htonl (retval);
   rmp->handle = session->vpp_handle;
   rmp->server_rx_fifo = pointer_to_uword (session->rx_fifo);
   rmp->server_tx_fifo = pointer_to_uword (session->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, svm_queue_t *);
   ASSERT (client_q);
   vl_msg_api_send_shmem (client_q, (u8 *) & rmp);
 }

 /*
  * Acting as server for redirected connect requests
  */
 static void
 vl_api_connect_sock_t_handler (vl_api_connect_sock_t * mp)
 {
   u32 session_index;
   session_t *session = 0;

   clib_spinlock_lock (&vcm->sessions_lockp);
   if (!clib_fifo_free_elts (vcm->client_session_index_fifo))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);

       if (VPPCOM_DEBUG > 1)
 	clib_warning ("VCL<%d>: client session queue is full!", getpid ());

       /* TBD: Fix api to include vpp handle */
       vppcom_send_connect_session_reply (0 /* session */ , 0 /* sid */ ,
 					 0 /* handle */ , mp->context,
 					 VNET_API_ERROR_QUEUE_FULL);
       return;
     }

   pool_get (vcm->sessions, session);
   memset (session, 0, sizeof (*session));
   session_index = session - vcm->sessions;

   session->client_context = mp->context;
   session->vpp_handle = session_index;
   session->client_queue_address = mp->client_queue_address;
   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;
   ASSERT (session->lcl_addr.is_ip4 == session->peer_addr.is_ip4);

   session->state = STATE_ACCEPT;
   clib_fifo_add1 (vcm->client_session_index_fifo, session_index);
   if (VPPCOM_DEBUG > 1)
     clib_warning ("VCL<%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));

   if (VPPCOM_DEBUG > 0)
     {
       session->elog_track.name =
 	(char *) format (0, "C:%d:S:%d%c", vcm->my_client_index,
 			 session_index, 0);
       elog_track_register (&vcm->elog_main, &session->elog_track);

       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
       {
 	.format = "cut-thru-connect:S:%d clib_fifo_elts:%d",
 	.format_args = "i4i4",
       };

       struct
       {
 	u32 data[2];
       } *ed;

       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

       ed->data[0] = session_index;
       ed->data[1] = clib_fifo_elts (vcm->client_session_index_fifo);
       /* *INDENT-ON* */
     }

   clib_spinlock_unlock (&vcm->sessions_lockp);
 }

 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 */
   bmp = vl_msg_api_alloc (sizeof (*bmp));
   memset (bmp, 0, sizeof (*bmp));

   bmp->_vl_msg_id = ntohs (VL_API_BIND_SOCK);
   bmp->client_index = vcm->my_client_index;
   bmp->context = session_index;
   bmp->is_ip4 = session->lcl_addr.is_ip4;
   clib_memcpy (bmp->ip, &session->lcl_addr.ip46, sizeof (bmp->ip));
   bmp->port = session->lcl_port;
   bmp->proto = session->proto;
   clib_memcpy (bmp->options, session->options, sizeof (bmp->options));
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & bmp);
 }

 static void
 vppcom_send_unbind_sock (u64 vpp_handle)
 {
   vl_api_unbind_sock_t *ump;

   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 = vpp_handle;
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & ump);
 }

 static int
 vppcom_session_unbind (u32 session_index)
 {
   session_t *session = 0;
   int rv;
   u64 vpp_handle;
   elog_track_t session_elog_track;

   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;
   session_elog_track = session->elog_track;

   clib_spinlock_unlock (&vcm->sessions_lockp);

   if (VPPCOM_DEBUG > 1)
     clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		  "sending unbind msg! new state 0x%x (%s)",
 		  getpid (), vpp_handle, session_index,
 		  STATE_DISCONNECT,
 		  vppcom_session_state_str (STATE_DISCONNECT));

   if (VPPCOM_DEBUG > 0)
     {
       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
       {
 	.format = "unbind: handle:%x",
 	.format_args = "i8",
       };

       struct
       {
 	u64 handle;
       } *ed;

       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session_elog_track);
       ed->handle = vpp_handle;
       /* *INDENT-ON* */
     }

   vppcom_send_unbind_sock (vpp_handle);

 done:
   return rv;
 }

 static inline int
 vppcom_session_disconnect (u32 session_index)
 {
   int rv;
   session_t *session;
   u64 vpp_handle;
   session_state_t state;

   VCL_LOCK_AND_GET_SESSION (session_index, &session);

   vpp_handle = session->vpp_handle;
   state = session->state;
   clib_spinlock_unlock (&vcm->sessions_lockp);

   if (VPPCOM_DEBUG > 1)
     {
       clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u "
 		    "state 0x%x (%s)",
 		    getpid (), vpp_handle, session_index,
 		    state, vppcom_session_state_str (state));
     }

   if (PREDICT_FALSE (state & STATE_LISTEN))
     {
       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 		    "Cannot disconnect a listen socket!",
 		    getpid (), vpp_handle, session_index);
       rv = VPPCOM_EBADFD;
       goto done;
     }

   /* The peer has already initiated the close,
    * so send the disconnect session reply.
    */
   if (state & STATE_CLOSE_ON_EMPTY)
     {
       //XXX alagalah - Check and drain here?
       vppcom_send_disconnect_session_reply (vpp_handle,
 					    session_index, 0 /* rv */ );
       if (VPPCOM_DEBUG > 1)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		      "sending disconnect REPLY...",
 		      getpid (), vpp_handle, session_index);
     }

   /* Otherwise, send a disconnect session msg...
    */
   else
     {
       if (VPPCOM_DEBUG > 1)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		      "sending disconnect...",
 		      getpid (), vpp_handle, session_index);

       vppcom_send_disconnect_session (vpp_handle, session_index);
     }

 done:
   return rv;
 }

 #define foreach_sock_msg                                        \
 _(SESSION_ENABLE_DISABLE_REPLY, session_enable_disable_reply)   \
 _(BIND_SOCK_REPLY, bind_sock_reply)                             \
 _(UNBIND_SOCK_REPLY, unbind_sock_reply)                         \
 _(ACCEPT_SESSION, accept_session)                               \
 _(CONNECT_SOCK, connect_sock)                                   \
 _(CONNECT_SESSION_REPLY, connect_session_reply)                 \
 _(DISCONNECT_SESSION, disconnect_session)                       \
 _(DISCONNECT_SESSION_REPLY, disconnect_session_reply)           \
 _(RESET_SESSION, reset_session)                                 \
 _(APPLICATION_ATTACH_REPLY, application_attach_reply)           \
 _(APPLICATION_DETACH_REPLY, application_detach_reply)           \
 _(MAP_ANOTHER_SEGMENT, map_another_segment)                     \
 _(UNMAP_SEGMENT, unmap_segment)

 static void
 vppcom_api_hookup (void)
 {
 #define _(N, n)                                                  \
     vl_msg_api_set_handlers(VL_API_##N, #n,                     \
                            vl_api_##n##_t_handler,              \
                            vl_noop_handler,                     \
                            vl_api_##n##_t_endian,               \
                            vl_api_##n##_t_print,                \
                            sizeof(vl_api_##n##_t), 1);
   foreach_sock_msg;
 #undef _
 }

 static void
 vppcom_cfg_init (vppcom_cfg_t * vcl_cfg)
 {
   ASSERT (vcl_cfg);

   vcl_cfg->heapsize = (256ULL << 20);
   vcl_cfg->vpp_api_q_length = 1024;
   vcl_cfg->segment_baseva = 0x200000000ULL;
   vcl_cfg->segment_size = (256 << 20);
   vcl_cfg->add_segment_size = (128 << 20);
   vcl_cfg->preallocated_fifo_pairs = 8;
   vcl_cfg->rx_fifo_size = (1 << 20);
   vcl_cfg->tx_fifo_size = (1 << 20);
   vcl_cfg->event_queue_size = 2048;
   vcl_cfg->listen_queue_size = CLIB_CACHE_LINE_BYTES / sizeof (u32);
   vcl_cfg->app_timeout = 10 * 60.0;
   vcl_cfg->session_timeout = 10 * 60.0;
   vcl_cfg->accept_timeout = 60.0;
   vcl_cfg->event_ring_size = (128 << 10);
   vcl_cfg->event_log_path = "/dev/shm";
 }

 static void
 vppcom_cfg_heapsize (char *conf_fname)
 {
   vppcom_cfg_t *vcl_cfg = &vcm->cfg;
   FILE *fp;
   char inbuf[4096];
   int argc = 1;
   char **argv = NULL;
   char *arg = NULL;
   char *p;
   int i;
   u8 *sizep;
   u32 size;
   void *vcl_mem;
   void *heap;

   fp = fopen (conf_fname, "r");
   if (fp == NULL)
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: using default heapsize %lld (0x%llx)",
 		      getpid (), vcl_cfg->heapsize, vcl_cfg->heapsize);
       goto defaulted;
     }

   argv = calloc (1, sizeof (char *));
   if (argv == NULL)
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: calloc failed, using default "
 		      "heapsize %lld (0x%llx)",
 		      getpid (), vcl_cfg->heapsize, vcl_cfg->heapsize);
       goto defaulted;
     }

   while (1)
     {
       if (fgets (inbuf, 4096, fp) == 0)
 	break;
       p = strtok (inbuf, " \t\n");
       while (p != NULL)
 	{
 	  if (*p == '#')
 	    break;
 	  argc++;
 	  char **tmp = realloc (argv, argc * sizeof (char *));
 	  if (tmp == NULL)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: realloc failed, "
 			      "using default heapsize %lld (0x%llx)",
 			      getpid (), vcl_cfg->heapsize,
 			      vcl_cfg->heapsize);
 	      goto defaulted;
 	    }
 	  argv = tmp;
 	  arg = strndup (p, 1024);
 	  if (arg == NULL)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: strndup failed, "
 			      "using default heapsize %lld (0x%llx)",
 			      getpid (), vcl_cfg->heapsize,
 			      vcl_cfg->heapsize);
 	      goto defaulted;
 	    }
 	  argv[argc - 1] = arg;
 	  p = strtok (NULL, " \t\n");
 	}
     }

   fclose (fp);
   fp = NULL;

   char **tmp = realloc (argv, (argc + 1) * sizeof (char *));
   if (tmp == NULL)
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: realloc failed, "
 		      "using default heapsize %lld (0x%llx)",
 		      getpid (), vcl_cfg->heapsize, vcl_cfg->heapsize);
       goto defaulted;
     }
   argv = tmp;
   argv[argc] = NULL;

   /*
    * Look for and parse the "heapsize" config parameter.
    * Manual since none of the clib infra has been bootstrapped yet.
    *
    * Format: heapsize <nn>[mM][gG]
    */

   for (i = 1; i < (argc - 1); i++)
     {
       if (!strncmp (argv[i], "heapsize", 8))
 	{
 	  sizep = (u8 *) argv[i + 1];
 	  size = 0;
 	  while (*sizep >= '0' && *sizep <= '9')
 	    {
 	      size *= 10;
 	      size += *sizep++ - '0';
 	    }
 	  if (size == 0)
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: parse error '%s %s', "
 			      "using default heapsize %lld (0x%llx)",
 			      getpid (), argv[i], argv[i + 1],
 			      vcl_cfg->heapsize, vcl_cfg->heapsize);
 	      goto defaulted;
 	    }

 	  if (*sizep == 'g' || *sizep == 'G')
 	    vcl_cfg->heapsize = size << 30;
 	  else if (*sizep == 'm' || *sizep == 'M')
 	    vcl_cfg->heapsize = size << 20;
 	  else
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: parse error '%s %s', "
 			      "using default heapsize %lld (0x%llx)",
 			      getpid (), argv[i], argv[i + 1],
 			      vcl_cfg->heapsize, vcl_cfg->heapsize);
 	      goto defaulted;
 	    }
 	}
     }

 defaulted:
   if (fp != NULL)
     fclose (fp);
   if (argv != NULL)
     free (argv);

   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 ("VCL<%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);
       ASSERT (vcl_mem != MAP_FAILED);
       return;
     }
   heap = clib_mem_init (vcl_mem, vcl_cfg->heapsize);
   if (!heap)
     {
       clib_warning ("VCL<%d>: ERROR: clib_mem_init() failed!", getpid ());
       ASSERT (heap);
       return;
     }
   vcl_mem = clib_mem_alloc (sizeof (_vppcom_main));
   if (!vcl_mem)
     {
       clib_warning ("VCL<%d>: ERROR: clib_mem_alloc() failed!", getpid ());
       ASSERT (vcl_mem);
       return;
     }

   clib_memcpy (vcl_mem, &_vppcom_main, sizeof (_vppcom_main));
   vcm = vcl_mem;

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%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_cfg_t *vcl_cfg = &vcm->cfg;
   int fd;
   unformat_input_t _input, *input = &_input;
   unformat_input_t _line_input, *line_input = &_line_input;
   u8 vc_cfg_input = 0;
   u8 *chroot_path;
   struct stat s;
   u32 uid, gid, q_len;

   fd = open (conf_fname, O_RDONLY);
   if (fd < 0)
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: using default configuration.",
 		      getpid (), conf_fname);
       goto file_done;
     }

   if (fstat (fd, &s) < 0)
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: failed to stat `%s', "
 		      "using default configuration", getpid (), conf_fname);
       goto file_done;
     }

   if (!(S_ISREG (s.st_mode) || S_ISLNK (s.st_mode)))
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: not a regular file `%s', "
 		      "using default configuration", getpid (), conf_fname);
       goto file_done;
     }

   unformat_init_clib_file (input, fd);

   while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
     {
       (void) unformat_user (input, unformat_line_input, line_input);
       unformat_skip_white_space (line_input);

       if (unformat (line_input, "vcl {"))
 	{
 	  vc_cfg_input = 1;
 	  continue;
 	}

       if (vc_cfg_input)
 	{
 	  if (unformat (line_input, "heapsize %s", &chroot_path))
 	    {
 	      vec_terminate_c_string (chroot_path);
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured heapsize %s, "
 			      "actual heapsize %lld (0x%llx)",
 			      getpid (), chroot_path, vcl_cfg->heapsize,
 			      vcl_cfg->heapsize);
 	      vec_free (chroot_path);
 	    }
 	  else if (unformat (line_input, "api-prefix %s", &chroot_path))
 	    {
 	      vec_terminate_c_string (chroot_path);
 	      if (vcl_cfg->vpp_api_filename)
 		vec_free (vcl_cfg->vpp_api_filename);
 	      vcl_cfg->vpp_api_filename = format (0, "/%s-vpe-api%c",
 						  chroot_path, 0);
 	      vl_set_memory_root_path ((char *) chroot_path);

 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured api-prefix (%s) and "
 			      "api filename (%s)", getpid (), chroot_path,
 			      vcl_cfg->vpp_api_filename);
 	      chroot_path = 0;	/* Don't vec_free() it! */
 	    }
 	  else if (unformat (line_input, "vpp-api-q-length %d", &q_len))
 	    {
 	      if (q_len < vcl_cfg->vpp_api_q_length)
 		{
 		  clib_warning ("VCL<%d>: ERROR: configured vpp-api-q-length "
 				"(%u) is too small! Using default: %u ",
 				getpid (), q_len, vcl_cfg->vpp_api_q_length);
 		}
 	      else
 		{
 		  vcl_cfg->vpp_api_q_length = q_len;

 		  if (VPPCOM_DEBUG > 0)
 		    clib_warning ("VCL<%d>: configured vpp-api-q-length %u",
 				  getpid (), vcl_cfg->vpp_api_q_length);
 		}
 	    }
 	  else if (unformat (line_input, "uid %d", &uid))
 	    {
 	      vl_set_memory_uid (uid);
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%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 ("VCL<%d>: configured gid %d", getpid (), gid);
 	    }
 	  else if (unformat (line_input, "segment-baseva 0x%lx",
 			     &vcl_cfg->segment_baseva))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%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 ("VCL<%d>: configured segment_size 0x%lx (%ld)",
 			      getpid (), vcl_cfg->segment_size,
 			      vcl_cfg->segment_size);
 	    }
 	  else if (unformat (line_input, "segment-size %ld",
 			     &vcl_cfg->segment_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured segment_size %ld (0x%lx)",
 			      getpid (), vcl_cfg->segment_size,
 			      vcl_cfg->segment_size);
 	    }
 	  else if (unformat (line_input, "add-segment-size 0x%lx",
 			     &vcl_cfg->add_segment_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning
 		  ("VCL<%d>: configured add_segment_size 0x%lx (%ld)",
 		   getpid (), vcl_cfg->add_segment_size,
 		   vcl_cfg->add_segment_size);
 	    }
 	  else if (unformat (line_input, "add-segment-size %ld",
 			     &vcl_cfg->add_segment_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning
 		  ("VCL<%d>: configured add_segment_size %ld (0x%lx)",
 		   getpid (), vcl_cfg->add_segment_size,
 		   vcl_cfg->add_segment_size);
 	    }
 	  else if (unformat (line_input, "preallocated-fifo-pairs %d",
 			     &vcl_cfg->preallocated_fifo_pairs))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured preallocated_fifo_pairs "
 			      "%d (0x%x)", getpid (),
 			      vcl_cfg->preallocated_fifo_pairs,
 			      vcl_cfg->preallocated_fifo_pairs);
 	    }
 	  else if (unformat (line_input, "rx-fifo-size 0x%lx",
 			     &vcl_cfg->rx_fifo_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured rx_fifo_size 0x%lx (%ld)",
 			      getpid (), vcl_cfg->rx_fifo_size,
 			      vcl_cfg->rx_fifo_size);
 	    }
 	  else if (unformat (line_input, "rx-fifo-size %ld",
 			     &vcl_cfg->rx_fifo_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured rx_fifo_size %ld (0x%lx)",
 			      getpid (), vcl_cfg->rx_fifo_size,
 			      vcl_cfg->rx_fifo_size);
 	    }
 	  else if (unformat (line_input, "tx-fifo-size 0x%lx",
 			     &vcl_cfg->tx_fifo_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured tx_fifo_size 0x%lx (%ld)",
 			      getpid (), vcl_cfg->tx_fifo_size,
 			      vcl_cfg->tx_fifo_size);
 	    }
 	  else if (unformat (line_input, "tx-fifo-size %ld",
 			     &vcl_cfg->tx_fifo_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured tx_fifo_size %ld (0x%lx)",
 			      getpid (), vcl_cfg->tx_fifo_size,
 			      vcl_cfg->tx_fifo_size);
 	    }
 	  else if (unformat (line_input, "event-queue-size 0x%lx",
 			     &vcl_cfg->event_queue_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured event_queue_size "
 			      "0x%lx (%ld)",
 			      getpid (), vcl_cfg->event_queue_size,
 			      vcl_cfg->event_queue_size);
 	    }
 	  else if (unformat (line_input, "event-queue-size %ld",
 			     &vcl_cfg->event_queue_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured event_queue_size "
 			      "%ld (0x%lx)",
 			      getpid (), vcl_cfg->event_queue_size,
 			      vcl_cfg->event_queue_size);
 	    }
 	  else if (unformat (line_input, "listen-queue-size 0x%lx",
 			     &vcl_cfg->listen_queue_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured listen_queue_size "
 			      "0x%lx (%ld)",
 			      getpid (), vcl_cfg->listen_queue_size,
 			      vcl_cfg->listen_queue_size);
 	    }
 	  else if (unformat (line_input, "listen-queue-size %ld",
 			     &vcl_cfg->listen_queue_size))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured listen_queue_size "
 			      "%ld (0x%lx)",
 			      getpid (), vcl_cfg->listen_queue_size,
 			      vcl_cfg->listen_queue_size);
 	    }
 	  else if (unformat (line_input, "app-timeout %f",
 			     &vcl_cfg->app_timeout))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured app_timeout %f",
 			      getpid (), vcl_cfg->app_timeout);
 	    }
 	  else if (unformat (line_input, "session-timeout %f",
 			     &vcl_cfg->session_timeout))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured session_timeout %f",
 			      getpid (), vcl_cfg->session_timeout);
 	    }
 	  else if (unformat (line_input, "accept-timeout %f",
 			     &vcl_cfg->accept_timeout))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: configured accept_timeout %f",
 			      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 ("VCL<%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 ("VCL<%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 ("VCL<%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 ("VCL<%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
 		  ("VCL<%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 ("VCL<%d>: configured namespace_id is "
 				  "too long, truncated to %d characters!",
 				  getpid (), max_nsid_vec_len);
 		}

 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%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 ("VCL<%d>: completed parsing vppcom config!",
 			      getpid ());
 	      goto input_done;
 	    }
 	  else
 	    {
 	      if (line_input->buffer[line_input->index] != '#')
 		{
 		  clib_warning ("VCL<%d>: Unknown vppcom config option: '%s'",
 				getpid (), (char *)
 				&line_input->buffer[line_input->index]);
 		}
 	    }
 	}
     }

 input_done:
   unformat_free (input);

 file_done:
   if (fd >= 0)
     close (fd);
 }

 /*
  * VPPCOM Public API functions
  */
 int
 vppcom_app_create (char *app_name)
 {
   vppcom_cfg_t *vcl_cfg = &vcm->cfg;
   u8 *heap;
   mheap_t *h;
   int rv;

   if (!vcm->init)
     {
       char *conf_fname;
       char *env_var_str;

       vcm->init = 1;
       vppcom_cfg_init (vcl_cfg);
       env_var_str = getenv (VPPCOM_ENV_DEBUG);
       if (env_var_str)
 	{
 	  u32 tmp;
 	  if (sscanf (env_var_str, "%u", &tmp) != 1)
 	    clib_warning ("VCL<%d>: Invalid debug level specified in "
 			  "the environment variable "
 			  VPPCOM_ENV_DEBUG
 			  " (%s)!\n", getpid (), env_var_str);
 	  else
 	    {
 	      vcm->debug = tmp;
 	      clib_warning ("VCL<%d>: configured VCL debug level (%u) from "
 			    VPPCOM_ENV_DEBUG "!", getpid (), vcm->debug);
 	    }
 	}
       conf_fname = getenv (VPPCOM_ENV_CONF);
       if (!conf_fname)
 	conf_fname = VPPCOM_CONF_DEFAULT;
       vppcom_cfg_heapsize (conf_fname);
       vcl_cfg = &vcm->cfg;
       clib_fifo_validate (vcm->client_session_index_fifo,
 			  vcm->cfg.listen_queue_size);
       vppcom_cfg_read (conf_fname);

       env_var_str = getenv (VPPCOM_ENV_API_PREFIX);
       if (env_var_str)
 	{
 	  if (vcl_cfg->vpp_api_filename)
 	    vec_free (vcl_cfg->vpp_api_filename);
 	  vcl_cfg->vpp_api_filename = format (0, "/%s-vpe-api%c",
 					      env_var_str, 0);
 	  vl_set_memory_root_path ((char *) env_var_str);

 	  if (VPPCOM_DEBUG > 0)
 	    clib_warning ("VCL<%d>: configured api prefix (%s) and "
 			  "filename (%s) from " VPPCOM_ENV_API_PREFIX "!",
 			  getpid (), env_var_str, vcl_cfg->vpp_api_filename);
 	}

       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 ("VCL<%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 ("VCL<%d>: configured namespace secret "
 			      "(%lu) from " VPPCOM_ENV_APP_NAMESPACE_ID "!",
 			      getpid (), vcm->cfg.namespace_secret);
 	    }
 	}
       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 ("VCL<%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 ("VCL<%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 ("VCL<%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 ("VCL<%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 ("VCL<%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 ("VCL<%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 ("VCL<%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);

       /* make the main heap thread-safe */
       h->flags |= MHEAP_FLAG_THREAD_SAFE;

       vcm->session_index_by_vpp_handles = hash_create (0, sizeof (uword));

       clib_time_init (&vcm->clib_time);
       vppcom_init_error_string_table ();
       svm_fifo_segment_main_init (vcl_cfg->segment_baseva,
 				  20 /* timeout in secs */ );
       clib_spinlock_init (&vcm->sessions_lockp);
     }

   if (vcm->my_client_index == ~0)
     {
       vppcom_api_hookup ();
       vcm->app_state = STATE_APP_START;
       rv = vppcom_connect_to_vpp (app_name);
       if (rv)
 	{
 	  clib_warning ("VCL<%d>: ERROR: couldn't connect to VPP!",
 			getpid ());
 	  return rv;
 	}

       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: sending session enable", getpid ());

       rv = vppcom_app_session_enable ();
       if (rv)
 	{
 	  clib_warning ("VCL<%d>: ERROR: vppcom_app_session_enable() "
 			"failed!", getpid ());
 	  return rv;
 	}

       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: sending app attach", getpid ());

       rv = vppcom_app_attach ();
       if (rv)
 	{
 	  clib_warning ("VCL<%d>: ERROR: vppcom_app_attach() failed!",
 			getpid ());
 	  return rv;
 	}

       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: app_name '%s', my_client_index %d (0x%x)",
 		      getpid (), app_name, vcm->my_client_index,
 		      vcm->my_client_index);
     }

   return VPPCOM_OK;
 }

 void
 vppcom_app_destroy (void)
 {
   int rv;

   if (vcm->my_client_index == ~0)
     return;

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: detaching from VPP, my_client_index %d (0x%x)",
 		  getpid (), vcm->my_client_index, vcm->my_client_index);

   if (VPPCOM_DEBUG > 0)
     {
       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
       {
 	.format = "app_detach:C:%d",
 	.format_args = "i4",
       };

       struct
       {
 	u32 data;
       } *ed;
       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, vcm->elog_track);
       ed->data = vcm->my_client_index;
       /* *INDENT-ON* */
     }

   vppcom_app_detach ();
   rv = vppcom_wait_for_app_state_change (STATE_APP_ENABLED);
   if (PREDICT_FALSE (rv))
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: application detach timed out! "
 		      "returning %d (%s)",
 		      getpid (), rv, vppcom_retval_str (rv));
     }

   /* Finished with logging before client gets reset to ~0 */
   if (VPPCOM_DEBUG > 0)
     write_elog ();

   vl_client_disconnect_from_vlib ();
   vcm->my_client_index = ~0;
   vcm->app_state = STATE_APP_START;
 }

 int
 vppcom_session_create (u8 proto, u8 is_nonblocking)
 {
   session_t *session;
   u32 session_index;
   session_state_t state;
   elog_track_t session_elog_track;

   clib_spinlock_lock (&vcm->sessions_lockp);
   pool_get (vcm->sessions, session);
   memset (session, 0, sizeof (*session));
   session_index = session - vcm->sessions;

   session->proto = proto;
   session->state = STATE_START;
   state = session->state;
   session->vpp_handle = ~0;

   if (is_nonblocking)
     VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_NONBLOCK);
   else
     VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_NONBLOCK);

   if (VPPCOM_DEBUG > 0)
     {
       session->elog_track.name =
 	(char *) format (0, "C:%d:S:%d%c", vcm->my_client_index,
 			 session_index, 0);
       elog_track_register (&vcm->elog_main, &session->elog_track);
       session_elog_track = session->elog_track;
     }

   clib_spinlock_unlock (&vcm->sessions_lockp);

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: sid %u", getpid (), session_index);

   if (VPPCOM_DEBUG > 0)
     {
       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
       {
 	.format = "session_create:proto:%d state:%d is_nonblocking:%d",
 	.format_args = "i4i4i4",
       };

       struct
       {
 	u32 data[3];
       } *ed;

       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session_elog_track);
       ed->data[0] = proto;
       ed->data[1] = state;
       ed->data[2] = is_nonblocking;
       /* *INDENT-ON* */
     }

   return (int) session_index;
 }

 int
 vppcom_session_close (uint32_t session_index)
 {
   session_t *session = 0;
   int rv;
   u8 is_vep;
   u8 is_vep_session;
   u32 next_sid;
   u32 vep_idx;
   u64 vpp_handle;
   uword *p;
   session_state_t state;
   elog_track_t session_elog_track;

   VCL_LOCK_AND_GET_SESSION (session_index, &session);
   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;
   vpp_handle = session->vpp_handle;
   clib_spinlock_unlock (&vcm->sessions_lockp);

   /*
    * Why two if(VPPCOM_DEBUG) checks?
    *
    * Eventually all clib_warnings need their own way of being
    * logged and signalled (like severity) where event logging
    * is a separate debugging tool. It will make the separation
    * easier. ... parting is such sweet sorrow ...
    */
   if (VPPCOM_DEBUG > 0)
     {
       session_elog_track = session->elog_track;
     }

   if (VPPCOM_DEBUG > 0)
     {
       if (is_vep)
 	clib_warning ("VCL<%d>: vep_idx %u / sid %u: "
 		      "closing epoll session...",
 		      getpid (), session_index, session_index);
       else
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %d: "
 		      "closing session...",
 		      getpid (), vpp_handle, session_index);
     }

   if (is_vep)
     {
       while (next_sid != ~0)
 	{
 	  rv = vppcom_epoll_ctl (session_index, EPOLL_CTL_DEL, next_sid, 0);
 	  if ((VPPCOM_DEBUG > 0) && PREDICT_FALSE (rv < 0))
 	    clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 			  "EPOLL_CTL_DEL vep_idx %u failed! rv %d (%s)",
 			  getpid (), vpp_handle, next_sid, vep_idx,
 			  rv, vppcom_retval_str (rv));

 	  VCL_LOCK_AND_GET_SESSION (session_index, &session);
 	  next_sid = session->vep.next_sid;
 	  clib_spinlock_unlock (&vcm->sessions_lockp);
 	}
     }
   else
     {
       if (is_vep_session)
 	{
 	  rv = vppcom_epoll_ctl (vep_idx, EPOLL_CTL_DEL, session_index, 0);
 	  if ((VPPCOM_DEBUG > 0) && (rv < 0))
 	    clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 			  "EPOLL_CTL_DEL vep_idx %u failed! rv %d (%s)",
 			  getpid (), vpp_handle, session_index,
 			  vep_idx, rv, vppcom_retval_str (rv));
 	}

       if (state & STATE_LISTEN)
 	{
 	  rv = vppcom_session_unbind (session_index);
 	  if (PREDICT_FALSE (rv < 0))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 			      "listener unbind failed! rv %d (%s)",
 			      getpid (), vpp_handle, session_index,
 			      rv, vppcom_retval_str (rv));
 	    }
 	}

       else if (state & (CLIENT_STATE_OPEN | SERVER_STATE_OPEN))
 	{
 	  rv = vppcom_session_disconnect (session_index);
 	  if (PREDICT_FALSE (rv < 0))
 	    clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 			  "session disconnect failed! rv %d (%s)",
 			  getpid (), vpp_handle, session_index,
 			  rv, vppcom_retval_str (rv));
 	}
     }

   VCL_LOCK_AND_GET_SESSION (session_index, &session);
   vpp_handle = session->vpp_handle;
   if (vpp_handle != ~0)
     {
       p = hash_get (vcm->session_index_by_vpp_handles, vpp_handle);
       if (p)
 	hash_unset (vcm->session_index_by_vpp_handles, vpp_handle);
     }
   pool_put_index (vcm->sessions, session_index);

   clib_spinlock_unlock (&vcm->sessions_lockp);

   if (VPPCOM_DEBUG > 0)
     {
       if (is_vep)
 	clib_warning ("VCL<%d>: vep_idx %u / sid %u: epoll session removed.",
 		      getpid (), session_index, session_index);
       else
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: session removed.",
 		      getpid (), vpp_handle, session_index);
     }
 done:

   if (VPPCOM_DEBUG > 0)
     {
       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
       {
 	.format = "session_close:rv:%d",
 	.format_args = "i4",
       };

       struct
       {
 	u32 data;
       } *ed;

       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session_elog_track);
       ed->data = rv;
       /* *INDENT-ON* */
     }

   return rv;
 }

 int
 vppcom_session_bind (uint32_t session_index, vppcom_endpt_t * ep)
 {
   session_t *session = 0;
   int rv;

   if (!ep || !ep->ip)
     return VPPCOM_EINVAL;

   VCL_LOCK_AND_GET_SESSION (session_index, &session);

   if (session->is_vep)
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
       clib_warning ("VCL<%d>: ERROR: sid %u: cannot "
 		    "bind to an epoll session!", getpid (), session_index);
       rv = VPPCOM_EBADFD;
       goto done;
     }

   session->lcl_addr.is_ip4 = ep->is_ip4;
   session->lcl_addr.ip46 = to_ip46 (!ep->is_ip4, ep->ip);
   session->lcl_port = ep->port;

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: sid %u: binding to local %s address %U "
 		  "port %u, proto %s", getpid (), session_index,
 		  session->lcl_addr.is_ip4 ? "IPv4" : "IPv6",
 		  format_ip46_address, &session->lcl_addr.ip46,
 		  session->lcl_addr.is_ip4,
 		  clib_net_to_host_u16 (session->lcl_port),
 		  session->proto ? "UDP" : "TCP");

   if (VPPCOM_DEBUG > 0)
     {
       if (session->lcl_addr.is_ip4)
 	{
           /* *INDENT-OFF* */
 	  ELOG_TYPE_DECLARE (e) =
 	  {
 	    .format = "bind local:%s:%d.%d.%d.%d:%d ",
 	    .format_args = "t1i1i1i1i1i2",
 	    .n_enum_strings = 2,
 	    .enum_strings = {"TCP", "UDP",},
 	  };

 	  CLIB_PACKED (struct {
 	    u8 proto;
 	    u8 addr[4];
 	    u16 port;
 	  }) * ed;

 	  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	  ed->proto = session->proto;
 	  ed->addr[0] = session->lcl_addr.ip46.ip4.as_u8[0];
 	  ed->addr[1] = session->lcl_addr.ip46.ip4.as_u8[1];
 	  ed->addr[2] = session->lcl_addr.ip46.ip4.as_u8[2];
 	  ed->addr[3] = session->lcl_addr.ip46.ip4.as_u8[3];
 	  ed->port = clib_net_to_host_u16 (session->lcl_port);
 	  /* *INDENT-ON* */
 	}
     }

   clib_spinlock_unlock (&vcm->sessions_lockp);
 done:
   return rv;
 }

 int
 vppcom_session_listen (uint32_t listen_session_index, uint32_t q_len)
 {
   session_t *listen_session = 0;
   u64 listen_vpp_handle;
   int rv, retval;

   if (q_len == 0 || q_len == ~0)
     q_len = vcm->cfg.listen_queue_size;

   VCL_LOCK_AND_GET_SESSION (listen_session_index, &listen_session);

   if (listen_session->is_vep)
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
       clib_warning ("VCL<%d>: ERROR: sid %u: cannot listen on an "
 		    "epoll session!", getpid (), listen_session_index);
       rv = VPPCOM_EBADFD;
       goto done;
     }

   listen_vpp_handle = listen_session->vpp_handle;
   if (listen_session->state & STATE_LISTEN)
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		      "already in listen state!",
 		      getpid (), listen_vpp_handle, listen_session_index);
       rv = VPPCOM_OK;
       goto done;
     }

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: vpp handle 0x%llx, "
 		  "sid %u: sending bind request...",
 		  getpid (), listen_vpp_handle, listen_session_index);

   vppcom_send_bind_sock (listen_session, listen_session_index);
   clib_spinlock_unlock (&vcm->sessions_lockp);
   retval =
     vppcom_wait_for_session_state_change (listen_session_index, STATE_LISTEN,
 					  vcm->cfg.session_timeout);

   VCL_LOCK_AND_GET_SESSION (listen_session_index, &listen_session);
   if (PREDICT_FALSE (retval))
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: bind failed! "
 		      "returning %d (%s)", getpid (),
 		      listen_session->vpp_handle, listen_session_index,
 		      retval, vppcom_retval_str (retval));
       clib_spinlock_unlock (&vcm->sessions_lockp);
       rv = retval;
       goto done;
     }

   clib_fifo_validate (vcm->client_session_index_fifo, q_len);
   clib_spinlock_unlock (&vcm->sessions_lockp);
 done:
   return rv;
 }

 int
 vppcom_session_accept (uint32_t listen_session_index, vppcom_endpt_t * ep,
 		       uint32_t flags)
 {
   session_t *listen_session = 0;
   session_t *client_session = 0;
   u32 client_session_index = ~0;
   int rv;
   f64 wait_for;
   u64 listen_vpp_handle;

   VCL_LOCK_AND_GET_SESSION (listen_session_index, &listen_session);

   if (listen_session->is_vep)
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
       clib_warning ("VCL<%d>: ERROR: sid %u: cannot accept on an "
 		    "epoll session!", getpid (), listen_session_index);
       rv = VPPCOM_EBADFD;
       goto done;
     }

   listen_vpp_handle = listen_session->vpp_handle;
   if (listen_session->state != STATE_LISTEN)
     {
       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 		    "not in listen state! state 0x%x (%s)", getpid (),
 		    listen_vpp_handle, listen_session_index,
 		    listen_session->state,
 		    vppcom_session_state_str (listen_session->state));
       clib_spinlock_unlock (&vcm->sessions_lockp);
       rv = VPPCOM_EBADFD;
       goto done;
     }
   wait_for = (VCL_SESS_ATTR_TEST (listen_session->attr,
 				  VCL_SESS_ATTR_NONBLOCK))
     ? 0 : vcm->cfg.accept_timeout;

   clib_spinlock_unlock (&vcm->sessions_lockp);

   while (1)
     {
       rv = vppcom_wait_for_client_session_index (wait_for);
       if (rv)
 	{
 	  if ((VPPCOM_DEBUG > 0))
 	    clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 			  "accept failed! returning %d (%s)", getpid (),
 			  listen_vpp_handle, listen_session_index,
 			  rv, vppcom_retval_str (rv));
 	  if (wait_for == 0)
 	    goto done;
 	}
       else
 	break;
     }

   clib_spinlock_lock (&vcm->sessions_lockp);
   clib_fifo_sub1 (vcm->client_session_index_fifo, client_session_index);
   rv = vppcom_session_at_index (client_session_index, &client_session);
   if (PREDICT_FALSE (rv))
     {
       rv = VPPCOM_ECONNABORTED;
       clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: client sid %u "
 		    "lookup failed! returning %d (%s)", getpid (),
 		    listen_vpp_handle, listen_session_index,
 		    client_session_index, rv, vppcom_retval_str (rv));
       goto done;
     }

   if (flags & O_NONBLOCK)
     VCL_SESS_ATTR_SET (client_session->attr, VCL_SESS_ATTR_NONBLOCK);
   else
     VCL_SESS_ATTR_CLR (client_session->attr, VCL_SESS_ATTR_NONBLOCK);

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: Got a client request! "
 		  "vpp handle 0x%llx, sid %u, flags %d, is_nonblocking %u",
 		  getpid (), listen_vpp_handle, listen_session_index,
 		  client_session->vpp_handle, client_session_index,
 		  flags, VCL_SESS_ATTR_TEST (client_session->attr,
 					     VCL_SESS_ATTR_NONBLOCK));

   if (ep)
     {
       ep->is_ip4 = client_session->peer_addr.is_ip4;
       ep->port = client_session->peer_port;
       if (client_session->peer_addr.is_ip4)
 	clib_memcpy (ep->ip, &client_session->peer_addr.ip46.ip4,
 		     sizeof (ip4_address_t));
       else
 	clib_memcpy (ep->ip, &client_session->peer_addr.ip46.ip6,
 		     sizeof (ip6_address_t));
     }

   vppcom_send_accept_session_reply (client_session->vpp_handle,
 				    client_session->client_context,
 				    0 /* retval OK */ );

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: accepted vpp handle "
 		  "0x%llx, sid %u connection to local %s address "
 		  "%U port %u", getpid (), listen_vpp_handle,
 		  listen_session_index, client_session->vpp_handle,
 		  client_session_index,
 		  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));

   if (VPPCOM_DEBUG > 0)
     {
       client_session->elog_track.name =
 	(char *) format (0, "C:%d:S:%d%c", vcm->my_client_index,
 			 client_session_index, 0);
       elog_track_register (&vcm->elog_main, &client_session->elog_track);

       // Two elog entries due to 20-byte per entry constraint.
       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
       {
 	.format = "accept: listen_handle:%x from_handle:%x",
 	.format_args = "i8i8",
       };

       struct
       {
 	u64 handle[2];
       } *ed;

       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, client_session->elog_track);
       ed->handle[0] = listen_vpp_handle;
       ed->handle[1] = client_session->vpp_handle;
       /* *INDENT-ON* */

       if (client_session->lcl_addr.is_ip4)
 	{
           /* *INDENT-OFF* */
 	  ELOG_TYPE_DECLARE (e2) =
 	  {
 	    .format = "accept: S:%d %d.%d.%d.%d:%d ",
 	    .format_args = "i4i1i1i1i1i2",
 	  };

 	  CLIB_PACKED (struct {
 	    u32 session;
 	    u8 addr[4];
 	    u16 port;
 	  }) * ed2;

 	  ed2 =
 	    ELOG_TRACK_DATA (&vcm->elog_main, e2, client_session->elog_track);
 	  ed2->session = client_session_index;
 	  ed2->addr[0] = client_session->lcl_addr.ip46.ip4.as_u8[0];
 	  ed2->addr[1] = client_session->lcl_addr.ip46.ip4.as_u8[1];
 	  ed2->addr[2] = client_session->lcl_addr.ip46.ip4.as_u8[2];
 	  ed2->addr[3] = client_session->lcl_addr.ip46.ip4.as_u8[3];
 	  ed2->port = clib_net_to_host_u16 (client_session->lcl_port);
 	  /* *INDENT-ON* */
 	}
     }

   clib_spinlock_unlock (&vcm->sessions_lockp);
   rv = (int) client_session_index;
 done:
   return rv;
 }

 int
 vppcom_session_connect (uint32_t session_index, vppcom_endpt_t * server_ep)
 {
   session_t *session = 0;
   u64 vpp_handle = 0;
   int rv, retval = VPPCOM_OK;

   VCL_LOCK_AND_GET_SESSION (session_index, &session);

   if (PREDICT_FALSE (session->is_vep))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
       clib_warning ("VCL<%d>: ERROR: sid %u: cannot "
 		    "connect on an epoll session!", getpid (), session_index);
       rv = VPPCOM_EBADFD;
       goto done;
     }

   if (PREDICT_FALSE (session->state & CLIENT_STATE_OPEN))
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: session already "
 		      "connected to %s %U port %d proto %s, state 0x%x (%s)",
 		      getpid (), session->vpp_handle, 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);
       goto done;
     }

   session->peer_addr.is_ip4 = server_ep->is_ip4;
   session->peer_addr.ip46 = to_ip46 (!server_ep->is_ip4, server_ep->ip);
   session->peer_port = server_ep->port;

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: connecting to server "
 		  "%s %U port %d proto %s",
 		  getpid (), session->vpp_handle, 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);

   retval =
     vppcom_wait_for_session_state_change (session_index, STATE_CONNECT,
 					  vcm->cfg.session_timeout);

   VCL_LOCK_AND_GET_SESSION (session_index, &session);
   vpp_handle = session->vpp_handle;
   clib_spinlock_unlock (&vcm->sessions_lockp);

 done:
   if (PREDICT_FALSE (retval))
     {
       rv = retval;
       if (VPPCOM_DEBUG > 0)
 	{
 	  if (session)
 	    clib_warning
 	      ("VCL<%d>: vpp handle 0x%llx, sid %u: connect failed! "
 	       "returning %d (%s)", getpid (), vpp_handle,
 	       session_index, rv, vppcom_retval_str (rv));
 	  else
 	    clib_warning ("VCL<%d>: no session for sid %u: connect failed! "
 			  "returning %d (%s)", getpid (),
 			  session_index, rv, vppcom_retval_str (rv));
 	}
     }
   else if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: connected!",
 		  getpid (), vpp_handle, session_index);

   return rv;
 }

 static inline int
 vppcom_session_read_internal (uint32_t session_index, void *buf, int n,
 			      u8 peek)
 {
   session_t *session = 0;
   svm_fifo_t *rx_fifo;
   int n_read = 0;
   int rv;
   int is_nonblocking;

   u64 vpp_handle;
   u32 poll_et;
   session_state_t state;

   ASSERT (buf);

   VCL_LOCK_AND_GET_SESSION (session_index, &session);

   is_nonblocking = VCL_SESS_ATTR_TEST (session->attr, VCL_SESS_ATTR_NONBLOCK);
   rx_fifo = session->rx_fifo;
   state = session->state;
   vpp_handle = session->vpp_handle;

   if (PREDICT_FALSE (session->is_vep))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
       clib_warning ("VCL<%d>: ERROR: sid %u: cannot "
 		    "read from an epoll session!", getpid (), session_index);
       rv = VPPCOM_EBADFD;
       goto done;
     }

   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 ("VCL<%d>: vpp handle 0x%llx, sid %u: %s session is "
 		      "not open! state 0x%x (%s), returning %d (%s)",
 		      getpid (), vpp_handle, session_index, state,
 		      vppcom_session_state_str (state),
 		      rv, vppcom_retval_str (rv));
       goto done;
     }

   clib_spinlock_unlock (&vcm->sessions_lockp);

   do
     {
       if (peek)
 	n_read = svm_fifo_peek (rx_fifo, 0, n, buf);
       else
 	n_read = svm_fifo_dequeue_nowait (rx_fifo, n, buf);
     }
   while (!is_nonblocking && (n_read <= 0));

   if (n_read <= 0)
     {
       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)
 	{
 	  rv = VPPCOM_ECONNRESET;

 	  if (VPPCOM_DEBUG > 1)
 	    {
 	      clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: Empty fifo "
 			    "with session state 0x%x (%s)!"
 			    "  Setting state to 0x%x (%s), returning %d (%s)",
 			    getpid (), session->vpp_handle, session_index,
 			    state, vppcom_session_state_str (state),
 			    STATE_DISCONNECT,
 			    vppcom_session_state_str (STATE_DISCONNECT), rv,
 			    vppcom_retval_str (rv));
 	    }

 	  session->state = STATE_DISCONNECT;
 	}
       else
 	rv = VPPCOM_EAGAIN;

       clib_spinlock_unlock (&vcm->sessions_lockp);
     }
   else
     rv = n_read;

   if (VPPCOM_DEBUG > 2)
     {
       if (rv > 0)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: read %d bytes "
 		      "from (%p)", getpid (), vpp_handle,
 		      session_index, n_read, rx_fifo);
       else
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: nothing read! "
 		      "returning %d (%s)", getpid (), vpp_handle,
 		      session_index, rv, vppcom_retval_str (rv));
     }
 done:
   return rv;
 }

 int
 vppcom_session_read (uint32_t session_index, void *buf, size_t n)
 {
   return (vppcom_session_read_internal (session_index, buf, n, 0));
 }

 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)
 {
   int ready = 0;
   u32 poll_et;
   int rv;
   session_state_t state = session->state;
   u64 vpp_handle = session->vpp_handle;

   /* Assumes caller has acquired spinlock: vcm->sessions_lockp */
   if (PREDICT_FALSE (session->is_vep))
     {
       clib_warning ("VCL<%d>: ERROR: sid %u: cannot read from an "
 		    "epoll session!", getpid (), session_index);
       rv = VPPCOM_EBADFD;
       goto done;
     }

   if (session->state & STATE_LISTEN)
     ready = clib_fifo_elts (vcm->client_session_index_fifo);
   else
     {
       if (!(state & (SERVER_STATE_OPEN | CLIENT_STATE_OPEN | STATE_LISTEN)))
 	{
 	  rv = ((state & STATE_DISCONNECT) ? VPPCOM_ECONNRESET :
 		VPPCOM_ENOTCONN);

 	  if (VPPCOM_DEBUG > 1)
 	    clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: session is "
 			  "not open! state 0x%x (%s), returning %d (%s)",
 			  getpid (), vpp_handle, session_index,
 			  state, vppcom_session_state_str (state),
 			  rv, vppcom_retval_str (rv));
 	  goto done;
 	}

       ready = svm_fifo_max_dequeue (session->rx_fifo);
     }

   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;

 	  if (VPPCOM_DEBUG > 1)
 	    {
 	      clib_warning ("VCL<%d>: vpp handle 0x%llx, "
 			    "sid %u: Empty fifo with"
 			    " session state 0x%x (%s)! Setting state to "
 			    "0x%x (%s), returning %d (%s)",
 			    getpid (), session_index, vpp_handle,
 			    state, vppcom_session_state_str (state),
 			    STATE_DISCONNECT,
 			    vppcom_session_state_str (STATE_DISCONNECT), rv,
 			    vppcom_retval_str (rv));
 	    }
 	  session->state = STATE_DISCONNECT;
 	  goto done;
 	}
     }
   rv = ready;

   if (vcm->app_event_queue->cursize &&
       !pthread_mutex_trylock (&vcm->app_event_queue->mutex))
     {
       u32 i, n_to_dequeue = vcm->app_event_queue->cursize;
       session_fifo_event_t e;

       for (i = 0; i < n_to_dequeue; i++)
 	svm_queue_sub_raw (vcm->app_event_queue, (u8 *) & e);

       pthread_mutex_unlock (&vcm->app_event_queue->mutex);
     }
 done:
   return rv;
 }

 int
 vppcom_session_write (uint32_t session_index, void *buf, size_t n)
 {
   session_t *session = 0;
   svm_fifo_t *tx_fifo = 0;
   svm_queue_t *q;
   session_fifo_event_t evt;
   session_state_t state;
   int rv, n_write, is_nonblocking;
   u32 poll_et;
   u64 vpp_handle;

   ASSERT (buf);

   VCL_LOCK_AND_GET_SESSION (session_index, &session);

   tx_fifo = session->tx_fifo;
   is_nonblocking = VCL_SESS_ATTR_TEST (session->attr, VCL_SESS_ATTR_NONBLOCK);
   vpp_handle = session->vpp_handle;
   state = session->state;

   if (PREDICT_FALSE (session->is_vep))
     {
       clib_spinlock_unlock (&vcm->sessions_lockp);
       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 		    "cannot write to an epoll session!",
 		    getpid (), vpp_handle, session_index);

       rv = VPPCOM_EBADFD;
       goto done;
     }

   if (!(session->state & (SERVER_STATE_OPEN | CLIENT_STATE_OPEN)))
     {
       rv =
 	((session->state & STATE_DISCONNECT) ? VPPCOM_ECONNRESET :
 	 VPPCOM_ENOTCONN);

       clib_spinlock_unlock (&vcm->sessions_lockp);
       if (VPPCOM_DEBUG > 1)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		      "session is not open! state 0x%x (%s)",
 		      getpid (), vpp_handle, session_index,
 		      state, vppcom_session_state_str (state));
       goto done;
     }

   clib_spinlock_unlock (&vcm->sessions_lockp);

   do
     {
       n_write = svm_fifo_enqueue_nowait (tx_fifo, n, (void *) buf);
     }
   while (!is_nonblocking && (n_write <= 0));

   /* If event wasn't set, add one */
   if ((n_write > 0) && svm_fifo_set_event (tx_fifo))
     {
       /* Fabricate TX event, send to vpp */
       evt.fifo = tx_fifo;
       evt.event_type = FIFO_EVENT_APP_TX;

       VCL_LOCK_AND_GET_SESSION (session_index, &session);
       q = session->vpp_event_queue;
       ASSERT (q);
       svm_queue_add (q, (u8 *) & evt, 0 /* do wait for mutex */ );
       clib_spinlock_unlock (&vcm->sessions_lockp);
       if (VPPCOM_DEBUG > 1)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		      "added FIFO_EVENT_APP_TX to "
 		      "vpp_event_q %p, n_write %d", getpid (),
 		      vpp_handle, session_index, q, n_write);
     }

   if (n_write <= 0)
     {
       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 (session->state & STATE_CLOSE_ON_EMPTY)
 	{
 	  rv = VPPCOM_ECONNRESET;

 	  if (VPPCOM_DEBUG > 1)
 	    {
 	      clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 			    "Empty fifo with session state 0x%x (%s)!"
 			    "  Setting state to 0x%x (%s), returning %d (%s)",
 			    getpid (), session->vpp_handle, session_index,
 			    session->state,
 			    vppcom_session_state_str (session->state),
 			    STATE_DISCONNECT,
 			    vppcom_session_state_str (STATE_DISCONNECT), rv,
 			    vppcom_retval_str (rv));
 	    }

 	  session->state = STATE_DISCONNECT;
 	}
       else
 	rv = VPPCOM_EAGAIN;

       clib_spinlock_unlock (&vcm->sessions_lockp);
     }
   else
     rv = n_write;

   if (VPPCOM_DEBUG > 2)
     {
       if (n_write <= 0)
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		      "FIFO-FULL (%p)", getpid (), vpp_handle,
 		      session_index, tx_fifo);
       else
 	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		      "wrote %d bytes tx-fifo: (%p)", getpid (),
 		      vpp_handle, session_index, n_write, tx_fifo);
     }
 done:
   return rv;
 }

 static inline int
 vppcom_session_write_ready (session_t * session, u32 session_index)
 {
   int ready;
   u32 poll_et;
   int rv;

   ASSERT (session);

   /* Assumes caller has acquired spinlock: vcm->sessions_lockp */
   if (PREDICT_FALSE (session->is_vep))
     {
       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 		    "cannot write to an epoll session!",
 		    getpid (), session->vpp_handle, session_index);
       rv = VPPCOM_EBADFD;
       goto done;
     }

   if (PREDICT_FALSE (session->state & STATE_LISTEN))
     {
       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 		    "cannot write to a listen session!",
 		    getpid (), session->vpp_handle, session_index);
       rv = VPPCOM_EBADFD;
       goto done;
     }

   if (!(session->state & (SERVER_STATE_OPEN | CLIENT_STATE_OPEN)))
     {
       session_state_t state = session->state;

       rv = ((state & STATE_DISCONNECT) ? VPPCOM_ECONNRESET : VPPCOM_ENOTCONN);

       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 		    "session is not open! state 0x%x (%s), "
 		    "returning %d (%s)", getpid (), session->vpp_handle,
 		    session_index,
 		    state, vppcom_session_state_str (state),
 		    rv, vppcom_retval_str (rv));
       goto done;
     }

   ready = svm_fifo_max_enqueue (session->tx_fifo);

   if (VPPCOM_DEBUG > 3)
     clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 		  "peek %s (%p), ready = %d", getpid (),
 		  session->vpp_handle, session_index,
 		  session->tx_fifo, ready);

   if (ready == 0)
     {
       poll_et = (((EPOLLET | EPOLLOUT) & session->vep.ev.events) ==
 		 (EPOLLET | EPOLLOUT));
       if (poll_et)
 	session->vep.et_mask |= EPOLLOUT;

       if (session->state & STATE_CLOSE_ON_EMPTY)
 	{
 	  rv = VPPCOM_ECONNRESET;

 	  if (VPPCOM_DEBUG > 1)
 	    {
 	      clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
 			    "Empty fifo with session "
 			    "state 0x%x (%s)! Setting state to 0x%x (%s), "
 			    "returning %d (%s)", getpid (),
 			    session->vpp_handle, session_index,
 			    session->state,
 			    vppcom_session_state_str (session->state),
 			    STATE_DISCONNECT,
 			    vppcom_session_state_str (STATE_DISCONNECT), rv,
 			    vppcom_retval_str (rv));
 	    }
 	  session->state = STATE_DISCONNECT;
 	  goto done;
 	}
     }
   rv = ready;
 done:
   return rv;
 }

 int
 vppcom_select (unsigned long n_bits, unsigned long *read_map,
 	       unsigned long *write_map, unsigned long *except_map,
 	       double time_to_wait)
 {
   u32 session_index;
   session_t *session = 0;
   int rv, bits_set = 0;
   f64 timeout = clib_time_now (&vcm->clib_time) + time_to_wait;
   u32 minbits = clib_max (n_bits, BITS (uword));

   ASSERT (sizeof (clib_bitmap_t) == sizeof (long int));

   if (n_bits && read_map)
     {
       clib_bitmap_validate (vcm->rd_bitmap, minbits);
       clib_memcpy (vcm->rd_bitmap, read_map,
 		   vec_len (vcm->rd_bitmap) * sizeof (clib_bitmap_t));
       memset (read_map, 0, vec_len (vcm->rd_bitmap) * sizeof (clib_bitmap_t));
     }
   if (n_bits && write_map)
     {
       clib_bitmap_validate (vcm->wr_bitmap, minbits);
       clib_memcpy (vcm->wr_bitmap, write_map,
 		   vec_len (vcm->wr_bitmap) * sizeof (clib_bitmap_t));
       memset (write_map, 0,
 	      vec_len (vcm->wr_bitmap) * sizeof (clib_bitmap_t));
     }
   if (n_bits && except_map)
     {
       clib_bitmap_validate (vcm->ex_bitmap, minbits);
       clib_memcpy (vcm->ex_bitmap, except_map,
 		   vec_len (vcm->ex_bitmap) * sizeof (clib_bitmap_t));
       memset (except_map, 0,
 	      vec_len (vcm->ex_bitmap) * sizeof (clib_bitmap_t));
     }

   do
     {
       /* *INDENT-OFF* */
       if (n_bits)
         {
           if (read_map)
             {
               clib_bitmap_foreach (session_index, vcm->rd_bitmap,
                 ({
                   clib_spinlock_lock (&vcm->sessions_lockp);
                   rv = vppcom_session_at_index (session_index, &session);
                   if (rv < 0)
                     {
                       clib_spinlock_unlock (&vcm->sessions_lockp);
                       if (VPPCOM_DEBUG > 1)
                         clib_warning ("VCL<%d>: session %d specified in "
                                       "read_map is closed.", getpid (),
                                       session_index);
                       bits_set = VPPCOM_EBADFD;
                       goto select_done;
                     }

                   rv = vppcom_session_read_ready (session, session_index);
                   clib_spinlock_unlock (&vcm->sessions_lockp);
                   if (except_map && vcm->ex_bitmap &&
                       clib_bitmap_get (vcm->ex_bitmap, session_index) &&
                       (rv < 0))
                     {
                       clib_bitmap_set_no_check (except_map, session_index, 1);
                       bits_set++;
                     }
                   else if (rv > 0)
                     {
                       clib_bitmap_set_no_check (read_map, session_index, 1);
                       bits_set++;
                     }
                 }));
             }

           if (write_map)
             {
               clib_bitmap_foreach (session_index, vcm->wr_bitmap,
                 ({
                   clib_spinlock_lock (&vcm->sessions_lockp);
                   rv = vppcom_session_at_index (session_index, &session);
                   if (rv < 0)
                     {
                       clib_spinlock_unlock (&vcm->sessions_lockp);
                       if (VPPCOM_DEBUG > 0)
                         clib_warning ("VCL<%d>: session %d specified in "
                                       "write_map is closed.", getpid (),
                                       session_index);
                       bits_set = VPPCOM_EBADFD;
                       goto select_done;
                     }

                   rv = vppcom_session_write_ready (session, session_index);
                   clib_spinlock_unlock (&vcm->sessions_lockp);
                   if (write_map && (rv > 0))
                     {
                       clib_bitmap_set_no_check (write_map, session_index, 1);
                       bits_set++;
                     }
                 }));
             }

           if (except_map)
             {
               clib_bitmap_foreach (session_index, vcm->ex_bitmap,
                 ({
                   clib_spinlock_lock (&vcm->sessions_lockp);
                   rv = vppcom_session_at_index (session_index, &session);
                   if (rv < 0)
                     {
                       clib_spinlock_unlock (&vcm->sessions_lockp);
                       if (VPPCOM_DEBUG > 1)
                         clib_warning ("VCL<%d>: session %d specified in "
                                       "except_map is closed.", getpid (),
                                       session_index);
                       bits_set = VPPCOM_EBADFD;
                       goto select_done;
                     }

                   rv = vppcom_session_read_ready (session, session_index);
                   clib_spinlock_unlock (&vcm->sessions_lockp);
                   if (rv < 0)
                     {
                       clib_bitmap_set_no_check (except_map, session_index, 1);
                       bits_set++;
                     }
                 }));
             }
         }
       /* *INDENT-ON* */
     }
   while ((time_to_wait == -1) || (clib_time_now (&vcm->clib_time) < timeout));

 select_done:
   return (bits_set);
 }

 static inline void
 vep_verify_epoll_chain (u32 vep_idx)
 {
   session_t *session;
   vppcom_epoll_t *vep;
   int rv;
   u32 sid = vep_idx;

   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 ("VCL<%d>: ERROR: Invalid vep_idx (%u)!",
 		    getpid (), vep_idx);
       goto done;
     }
   if (PREDICT_FALSE (!session->is_vep))
     {
       clib_warning ("VCL<%d>: ERROR: vep_idx (%u) is not a vep!",
 		    getpid (), vep_idx);
       goto done;
     }
   vep = &session->vep;
   clib_warning ("VCL<%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))
 	{
 	  clib_warning ("VCL<%d>: ERROR: Invalid sid (%u)!", getpid (), sid);
 	  goto done;
 	}
       if (PREDICT_FALSE (session->is_vep))
 	clib_warning ("VCL<%d>: ERROR: sid (%u) is a vep!",
 		      getpid (), vep_idx);
       else if (PREDICT_FALSE (!session->is_vep_session))
 	{
 	  clib_warning ("VCL<%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 ("VCL<%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);
 	}
     }

 done:
   clib_warning ("VCL<%d>: vep_idx (%u): Dump complete!\n",
 		getpid (), vep_idx);
 }

 int
 vppcom_epoll_create (void)
 {
   session_t *vep_session;
   u32 vep_idx;
   elog_track_t vep_elog_track;

   clib_spinlock_lock (&vcm->sessions_lockp);
   pool_get (vcm->sessions, vep_session);
   memset (vep_session, 0, sizeof (*vep_session));
   vep_idx = vep_session - vcm->sessions;

   vep_session->is_vep = 1;
   vep_session->vep.vep_idx = ~0;
   vep_session->vep.next_sid = ~0;
   vep_session->vep.prev_sid = ~0;
   vep_session->wait_cont_idx = ~0;
   vep_session->vpp_handle = ~0;

   if (VPPCOM_DEBUG > 0)
     {
       vep_session->elog_track.name =
 	(char *) format (0, "C:%d:VEP:%d%c", vcm->my_client_index,
 			 vep_idx, 0);
       elog_track_register (&vcm->elog_main, &vep_session->elog_track);
       vep_elog_track = vep_session->elog_track;
     }

   clib_spinlock_unlock (&vcm->sessions_lockp);

   if (VPPCOM_DEBUG > 0)
     clib_warning ("VCL<%d>: Created vep_idx %u / sid %u!",
 		  getpid (), vep_idx, vep_idx);

   if (VPPCOM_DEBUG > 0)
     {

       /* *INDENT-OFF* */
       ELOG_TYPE_DECLARE (e) =
       {
 	.format = "created epoll session:%d",
 	.format_args = "i4",
       };

       struct
       {
 	u32 data;
       } *ed;

       ed = ELOG_TRACK_DATA (&vcm->elog_main, e, vep_elog_track);
       ed->data = vep_idx;
       /* *INDENT-ON* */
     }

   return (vep_idx);
 }

 int
 vppcom_epoll_ctl (uint32_t vep_idx, int op, uint32_t session_index,
 		  struct epoll_event *event)
 {
   session_t *vep_session;
   session_t *session;
   int rv;

   if (vep_idx == session_index)
     {
       clib_warning ("VCL<%d>: ERROR: vep_idx == session_index (%u)!",
 		    getpid (), vep_idx);
       return VPPCOM_EINVAL;
     }

   clib_spinlock_lock (&vcm->sessions_lockp);
   rv = vppcom_session_at_index (vep_idx, &vep_session);
   if (PREDICT_FALSE (rv))
     {
       clib_warning ("VCL<%d>: ERROR: Invalid vep_idx (%u)!", vep_idx);
       goto done;
     }
   if (PREDICT_FALSE (!vep_session->is_vep))
     {
       clib_warning ("VCL<%d>: ERROR: vep_idx (%u) is not a vep!",
 		    getpid (), vep_idx);
       rv = VPPCOM_EINVAL;
       goto done;
     }

   ASSERT (vep_session->vep.vep_idx == ~0);
   ASSERT (vep_session->vep.prev_sid == ~0);

   rv = vppcom_session_at_index (session_index, &session);
   if (PREDICT_FALSE (rv))
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: ERROR: Invalid session_index (%u)!",
 		      getpid (), session_index);
       goto done;
     }
   if (PREDICT_FALSE (session->is_vep))
     {
       clib_warning ("ERROR: session_index (%u) is a vep!", vep_idx);
       rv = VPPCOM_EINVAL;
       goto done;
     }

   switch (op)
     {
     case EPOLL_CTL_ADD:
       if (PREDICT_FALSE (!event))
 	{
 	  clib_warning ("VCL<%d>: ERROR: EPOLL_CTL_ADD: NULL pointer to "
 			"epoll_event structure!", getpid ());
 	  rv = VPPCOM_EINVAL;
 	  goto done;
 	}
       if (vep_session->vep.next_sid != ~0)
 	{
 	  session_t *next_session;
 	  rv = vppcom_session_at_index (vep_session->vep.next_sid,
 					&next_session);
 	  if (PREDICT_FALSE (rv))
 	    {
 	      clib_warning ("VCL<%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);
 	  next_session->vep.prev_sid = session_index;
 	}
       session->vep.next_sid = vep_session->vep.next_sid;
       session->vep.prev_sid = vep_idx;
       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 ("VCL<%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);
       if (VPPCOM_DEBUG > 0)
 	{
           /* *INDENT-OFF* */
 	  ELOG_TYPE_DECLARE (e) =
 	    {
 	      .format = "epoll_ctladd: events:%x data:%x",
 	      .format_args = "i4i4i8",
 	    };
 	  struct
 	  {
 	    u32 events;
 	    u64 event_data;
 	  } *ed;

 	  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 	  ed->events = event->events;
 	  ed->event_data = event->data.u64;
 	  /* *INDENT-ON* */
 	}
       break;

     case EPOLL_CTL_MOD:
       if (PREDICT_FALSE (!event))
 	{
 	  clib_warning ("VCL<%d>: ERROR: EPOLL_CTL_MOD: NULL pointer to "
 			"epoll_event structure!", getpid ());
 	  rv = VPPCOM_EINVAL;
 	  goto done;
 	}
       else if (PREDICT_FALSE (!session->is_vep_session))
 	{
 	  clib_warning ("VCL<%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 ("VCL<%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
 	  ("VCL<%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))
 	{
 	  clib_warning ("VCL<%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 ("VCL<%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;
 	}

       vep_session->wait_cont_idx =
 	(vep_session->wait_cont_idx == session_index) ?
 	session->vep.next_sid : vep_session->wait_cont_idx;

       if (session->vep.prev_sid == vep_idx)
 	vep_session->vep.next_sid = session->vep.next_sid;
       else
 	{
 	  session_t *prev_session;
 	  rv = vppcom_session_at_index (session->vep.prev_sid, &prev_session);
 	  if (PREDICT_FALSE (rv))
 	    {
 	      clib_warning ("VCL<%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);
 	  prev_session->vep.next_sid = session->vep.next_sid;
 	}
       if (session->vep.next_sid != ~0)
 	{
 	  session_t *next_session;
 	  rv = vppcom_session_at_index (session->vep.next_sid, &next_session);
 	  if (PREDICT_FALSE (rv))
 	    {
 	      clib_warning ("VCL<%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);
 	  next_session->vep.prev_sid = session->vep.prev_sid;
 	}

       memset (&session->vep, 0, sizeof (session->vep));
       session->vep.next_sid = ~0;
       session->vep.prev_sid = ~0;
       session->vep.vep_idx = ~0;
       session->is_vep_session = 0;
       if (VPPCOM_DEBUG > 1)
 	clib_warning ("VCL<%d>: EPOLL_CTL_DEL: vep_idx %u, sid %u!",
 		      getpid (), vep_idx, session_index);
       if (VPPCOM_DEBUG > 0)
 	{
           /* *INDENT-OFF* */
 	  ELOG_TYPE_DECLARE (e) =
 	    {
 	      .format = "epoll_ctldel: vep:%d",
 	      .format_args = "i4",
 	    };
 	  struct
 	  {
 	    u32 data;
 	  } *ed;

 	  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 	  ed->data = vep_idx;
 	  /* *INDENT-ON* */
 	}
       break;

     default:
       clib_warning ("VCL<%d>: ERROR: Invalid operation (%d)!", getpid (), op);
       rv = VPPCOM_EINVAL;
     }

   vep_verify_epoll_chain (vep_idx);

 done:
   clib_spinlock_unlock (&vcm->sessions_lockp);
   return rv;
 }

 int
 vppcom_epoll_wait (uint32_t vep_idx, struct epoll_event *events,
 		   int maxevents, double wait_for_time)
 {
   session_t *vep_session;
   elog_track_t vep_elog_track;
   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))
     {
       clib_warning ("VCL<%d>: ERROR: Invalid maxevents (%d)!",
 		    getpid (), maxevents);
       return VPPCOM_EINVAL;
     }
   memset (events, 0, sizeof (*events) * maxevents);

   VCL_LOCK_AND_GET_SESSION (vep_idx, &vep_session);
   vep_next_sid = vep_session->vep.next_sid;
   is_vep = vep_session->is_vep;
   wait_cont_idx = vep_session->wait_cont_idx;
   vep_elog_track = vep_session->elog_track;
   clib_spinlock_unlock (&vcm->sessions_lockp);

   if (PREDICT_FALSE (!is_vep))
     {
       clib_warning ("VCL<%d>: ERROR: vep_idx (%u) is not a vep!",
 		    getpid (), vep_idx);
       rv = VPPCOM_EINVAL;
       goto done;
     }
   if (PREDICT_FALSE (vep_next_sid == ~0))
     {
       if (VPPCOM_DEBUG > 0)
 	clib_warning ("VCL<%d>: WARNING: vep_idx (%u) is empty!",
 		      getpid (), vep_idx);
       if (VPPCOM_DEBUG > 0)
 	{
           /* *INDENT-OFF* */
 	  ELOG_TYPE_DECLARE (e) =
 	    {
 	      .format = "WRN: vep_idx:%d empty",
 	      .format_args = "i4",
 	    };
 	  struct
 	  {
 	    u32 data;
 	  } *ed;

 	  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, vep_elog_track);

 	  ed->data = vep_idx;
 	  /* *INDENT-ON* */
 	}
       goto done;
     }

   do
     {
       u32 sid;
       u32 next_sid = ~0;
       session_t *session;
       elog_track_t session_elog_track;

       for (sid = (wait_cont_idx == ~0) ? vep_next_sid : wait_cont_idx;
 	   sid != ~0; sid = next_sid)
 	{
 	  u32 session_events, et_mask, clear_et_mask, session_vep_idx;
 	  u8 add_event, is_vep_session;
 	  int ready;
 	  u64 session_ev_data;

 	  VCL_LOCK_AND_GET_SESSION (sid, &session);
 	  next_sid = session->vep.next_sid;
 	  session_events = session->vep.ev.events;
 	  et_mask = session->vep.et_mask;
 	  is_vep = session->is_vep;
 	  is_vep_session = session->is_vep_session;
 	  session_vep_idx = session->vep.vep_idx;
 	  session_ev_data = session->vep.ev.data.u64;

 	  if (VPPCOM_DEBUG > 0)
 	    {
 	      session_elog_track = session->elog_track;
 	    }

 	  clib_spinlock_unlock (&vcm->sessions_lockp);

 	  if (PREDICT_FALSE (is_vep))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: ERROR: sid (%u) is a vep!",
 			      getpid (), vep_idx);
 	      if (VPPCOM_DEBUG > 0)
 		{
                   /* *INDENT-OFF* */
 		  ELOG_TYPE_DECLARE (e) =
 		    {
 		      .format = "ERR:vep_idx:%d is vep",
 		      .format_args = "i4",
 		    };
 		  struct
 		  {
 		    u32 data;
 		  } *ed;

 		  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session_elog_track);

 		  ed->data = vep_idx;
 		  /* *INDENT-ON* */
 		}

 	      rv = VPPCOM_EINVAL;
 	      goto done;
 	    }
 	  if (PREDICT_FALSE (!is_vep_session))
 	    {
 	      if (VPPCOM_DEBUG > 0)
 		clib_warning ("VCL<%d>: ERROR: session (%u) is not "
 			      "a vep session!", getpid (), sid);
 	      if (VPPCOM_DEBUG > 0)
 		{
                   /* *INDENT-OFF* */
 		  ELOG_TYPE_DECLARE (e) =
 		    {
 		      .format = "ERR:SID:%d not vep",
 		      .format_args = "i4",
 		    };
 		  struct
 		  {
 		    u32 data;
 		  } *ed;

 		  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session_elog_track);

 		  ed->data = sid;
 		  /* *INDENT-ON* */
 		}

 	      rv = VPPCOM_EINVAL;
 	      goto done;
 	    }
 	  if (PREDICT_FALSE (session_vep_idx != vep_idx))
 	    {
 	      clib_warning ("VCL<%d>: ERROR: session (%u) "
 			    "vep_idx (%u) != vep_idx (%u)!",
 			    getpid (), sid, session_vep_idx, vep_idx);
 	      rv = VPPCOM_EINVAL;
 	      goto done;
 	    }

 	  add_event = clear_et_mask = 0;

 	  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) && (EPOLLIN & et_mask))
 		{
 		  add_event = 1;
 		  events[num_ev].events |= EPOLLIN;
 		  if (((EPOLLET | EPOLLIN) & session_events) ==
 		      (EPOLLET | EPOLLIN))
 		    clear_et_mask |= EPOLLIN;
 		}
 	      else if (ready < 0)
 		{
 		  add_event = 1;
 		  switch (ready)
 		    {
 		    case VPPCOM_ECONNRESET:
 		      events[num_ev].events |= EPOLLHUP | EPOLLRDHUP;
 		      break;

 		    default:
 		      events[num_ev].events |= EPOLLERR;
 		      break;
 		    }
 		}
 	    }

 	  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) && (EPOLLOUT & et_mask))
 		{
 		  add_event = 1;
 		  events[num_ev].events |= EPOLLOUT;
 		  if (((EPOLLET | EPOLLOUT) & session_events) ==
 		      (EPOLLET | EPOLLOUT))
 		    clear_et_mask |= EPOLLOUT;
 		}
 	      else if (ready < 0)
 		{
 		  add_event = 1;
 		  switch (ready)
 		    {
 		    case VPPCOM_ECONNRESET:
 		      events[num_ev].events |= EPOLLHUP;
 		      break;

 		    default:
 		      events[num_ev].events |= EPOLLERR;
 		      break;
 		    }
 		}
 	    }

 	  if (add_event)
 	    {
 	      events[num_ev].data.u64 = session_ev_data;
 	      if (EPOLLONESHOT & session_events)
 		{
 		  VCL_LOCK_AND_GET_SESSION (sid, &session);
 		  session->vep.ev.events = 0;
 		  clib_spinlock_unlock (&vcm->sessions_lockp);
 		}
 	      num_ev++;
 	      if (num_ev == maxevents)
 		{
 		  VCL_LOCK_AND_GET_SESSION (vep_idx, &vep_session);
 		  vep_session->wait_cont_idx = next_sid;
 		  clib_spinlock_unlock (&vcm->sessions_lockp);
 		  goto done;
 		}
 	    }
 	  if (wait_cont_idx != ~0)
 	    {
 	      if (next_sid == ~0)
 		next_sid = vep_next_sid;
 	      else if (next_sid == wait_cont_idx)
 		next_sid = ~0;
 	    }
 	}
       if (wait_for_time != -1)
 	keep_trying = (clib_time_now (&vcm->clib_time) <= timeout) ? 1 : 0;
     }
   while ((num_ev == 0) && keep_trying);

   if (wait_cont_idx != ~0)
     {
       VCL_LOCK_AND_GET_SESSION (vep_idx, &vep_session);
       vep_session->wait_cont_idx = ~0;
       clib_spinlock_unlock (&vcm->sessions_lockp);
     }
 done:
   return (rv != VPPCOM_OK) ? rv : num_ev;
 }

 int
 vppcom_session_attr (uint32_t session_index, uint32_t op,
 		     void *buffer, uint32_t * buflen)
 {
   session_t *session;
   int rv = VPPCOM_OK;
   u32 *flags = buffer;
   vppcom_endpt_t *ep = buffer;

   VCL_LOCK_AND_GET_SESSION (session_index, &session);

   ASSERT (session);

   switch (op)
     {
     case VPPCOM_ATTR_GET_NREAD:
       rv = vppcom_session_read_ready (session, session_index);
       if (VPPCOM_DEBUG > 2)
 	clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_NREAD: sid %u, nread = %d",
 		      getpid (), rv);
       if (VPPCOM_DEBUG > 0)
 	{
           /* *INDENT-OFF* */
 	  ELOG_TYPE_DECLARE (e) =
 	    {
 	      .format = "VPPCOM_ATTR_GET_NREAD: nread=%d",
 	      .format_args = "i4",
 	    };
 	  struct
 	  {
 	    u32 data;
 	  } *ed;

 	  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 	  ed->data = rv;
 	  /* *INDENT-ON* */
 	}

       break;

     case VPPCOM_ATTR_GET_NWRITE:
       rv = vppcom_session_write_ready (session, session_index);
       if (VPPCOM_DEBUG > 2)
 	clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_NWRITE: sid %u, nwrite = %d",
 		      getpid (), session_index, rv);
       if (VPPCOM_DEBUG > 0)
 	{
           /* *INDENT-OFF* */
 	  ELOG_TYPE_DECLARE (e) =
 	    {
 	      .format = "VPPCOM_ATTR_GET_NWRITE: nwrite=%d",
 	      .format_args = "i4",
 	    };
 	  struct
 	  {
 	    u32 data;
 	  } *ed;

 	  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 	  ed->data = rv;
 	  /* *INDENT-ON* */
 	}
       break;

     case VPPCOM_ATTR_GET_FLAGS:
       if (PREDICT_TRUE (buffer && buflen && (*buflen >= sizeof (*flags))))
 	{
 	  *flags = O_RDWR | (VCL_SESS_ATTR_TEST (session->attr,
 						 VCL_SESS_ATTR_NONBLOCK));
 	  *buflen = sizeof (*flags);
 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_FLAGS: sid %u, "
 			  "flags = 0x%08x, is_nonblocking = %u", getpid (),
 			  session_index, *flags,
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_NONBLOCK));
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_FLAGS: flags=%x is_nonblk=%d",
 		  .format_args = "i4i4",
 		};
 	      struct
 	      {
 		u32 flags;
 		u32 is_nonblk;
 	      } *ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 	      ed->flags = *flags;
 	      ed->is_nonblk = VCL_SESS_ATTR_TEST (session->attr, VCL_SESS_ATTR_NONBLOCK);
 	      /* *INDENT-ON* */
 	    }

 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_FLAGS:
       if (PREDICT_TRUE (buffer && buflen && (*buflen == sizeof (*flags))))
 	{
 	  if (*flags & O_NONBLOCK)
 	    VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_NONBLOCK);
 	  else
 	    VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_NONBLOCK);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_FLAGS: sid %u, "
 			  "flags = 0x%08x, is_nonblocking = %u",
 			  getpid (), session_index, *flags,
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_NONBLOCK));
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_FLAGS: flags=%x is_nonblk=%d",
 		  .format_args = "i4i4",
 		};
 	      struct
 	      {
 		u32 flags;
 		u32 is_nonblk;
 	      } *ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 	      ed->flags = *flags;
 	      ed->is_nonblk = VCL_SESS_ATTR_TEST (session->attr, VCL_SESS_ATTR_NONBLOCK);
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_PEER_ADDR:
       if (PREDICT_TRUE (buffer && buflen &&
 			(*buflen >= sizeof (*ep)) && ep->ip))
 	{
 	  ep->is_ip4 = session->peer_addr.is_ip4;
 	  ep->port = session->peer_port;
 	  if (session->peer_addr.is_ip4)
 	    clib_memcpy (ep->ip, &session->peer_addr.ip46.ip4,
 			 sizeof (ip4_address_t));
 	  else
 	    clib_memcpy (ep->ip, &session->peer_addr.ip46.ip6,
 			 sizeof (ip6_address_t));
 	  *buflen = sizeof (*ep);
 	  if (VPPCOM_DEBUG > 1)
 	    clib_warning ("VCL<%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));
 	  if (VPPCOM_DEBUG > 0)
 	    {
 	      if (ep->is_ip4)
 		{
                     /* *INDENT-OFF* */
 		  ELOG_TYPE_DECLARE (e) =
 		    {
 		      .format = "VPPCOM_ATTR_GET_PEER_ADDR: addr:%d.%d.%d.%d:%d",
 		      .format_args = "i1i1i1i1i2",
 		    };
 		  CLIB_PACKED (struct {
 		    u8 addr[4];	//4
 		    u16 port;	//2
 		  }) * ed;

 		  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 		  ed->addr[0] = session->peer_addr.ip46.ip4.as_u8[0];
 		  ed->addr[1] = session->peer_addr.ip46.ip4.as_u8[1];
 		  ed->addr[2] = session->peer_addr.ip46.ip4.as_u8[2];
 		  ed->addr[3] = session->peer_addr.ip46.ip4.as_u8[3];
 		  ed->port = clib_net_to_host_u16 (session->peer_port);
 		  /* *INDENT-ON* */
 		}
 	      else
 		{
                     /* *INDENT-OFF* */
 		  ELOG_TYPE_DECLARE (e) =
 		    {
 		      .format = "VPPCOM_ATTR_GET_PEER_ADDR: addr:IP6:%d",
 		      .format_args = "i2",
 		    };
 		  CLIB_PACKED (struct {
 		    u16 port;	//2
 		  }) * ed;

 		  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 		  ed->port = clib_net_to_host_u16 (session->peer_port);
 		  /* *INDENT-ON* */
 		}
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_LCL_ADDR:
       if (PREDICT_TRUE (buffer && buflen &&
 			(*buflen >= sizeof (*ep)) && ep->ip))
 	{
 	  ep->is_ip4 = session->lcl_addr.is_ip4;
 	  ep->port = session->lcl_port;
 	  if (session->lcl_addr.is_ip4)
 	    clib_memcpy (ep->ip, &session->lcl_addr.ip46.ip4,
 			 sizeof (ip4_address_t));
 	  else
 	    clib_memcpy (ep->ip, &session->lcl_addr.ip46.ip6,
 			 sizeof (ip6_address_t));
 	  *buflen = sizeof (*ep);
 	  if (VPPCOM_DEBUG > 1)
 	    clib_warning ("VCL<%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));
 	  if (VPPCOM_DEBUG > 0)
 	    {
 	      if (ep->is_ip4)
 		{
                     /* *INDENT-OFF* */
 		  ELOG_TYPE_DECLARE (e) =
 		    {
 		      .format = "VPPCOM_ATTR_GET_LCL_ADDR: addr:%d.%d.%d.%d:%d",
 		      .format_args = "i1i1i1i1i2",
 		    };
 		  CLIB_PACKED (struct {
 		    u8 addr[4];	//4
 		    u16 port;	//2
 		  }) * ed;

 		  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 		  ed->addr[0] = session->lcl_addr.ip46.ip4.as_u8[0];
 		  ed->addr[1] = session->lcl_addr.ip46.ip4.as_u8[1];
 		  ed->addr[2] = session->lcl_addr.ip46.ip4.as_u8[2];
 		  ed->addr[3] = session->lcl_addr.ip46.ip4.as_u8[3];
 		  ed->port = clib_net_to_host_u16 (session->peer_port);
 		  /* *INDENT-ON* */
 		}
 	      else
 		{
                     /* *INDENT-OFF* */
 		  ELOG_TYPE_DECLARE (e) =
 		    {
 		      .format = "VPPCOM_ATTR_GET_LCL_ADDR: addr:IP6:%d",
 		      .format_args = "i2",
 		    };
 		  CLIB_PACKED (struct {
 		    u16 port;	//2
 		  }) * ed;

 		  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 		  ed->port = clib_net_to_host_u16 (session->peer_port);
 		  /* *INDENT-ON* */
 		}
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_LIBC_EPFD:
       rv = session->libc_epfd;
       if (VPPCOM_DEBUG > 2)
 	clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_LIBC_EPFD: libc_epfd %d",
 		      getpid (), rv);
       if (VPPCOM_DEBUG > 0)
 	{
           /* *INDENT-OFF* */
 	  ELOG_TYPE_DECLARE (e) =
 	    {
 	      .format = "VPPCOM_ATTR_GET_LIBC_EPFD: libc_epfd=%d",
 	      .format_args = "i4",
 	    };
 	  CLIB_PACKED (struct {
 	    i32 data;
 	  }) * ed;

 	  ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	  ed->data = session->libc_epfd;
 	  /* *INDENT-ON* */
 	}

       break;

     case VPPCOM_ATTR_SET_LIBC_EPFD:
       if (PREDICT_TRUE (buffer && buflen &&
 			(*buflen == sizeof (session->libc_epfd))))
 	{
 	  session->libc_epfd = *(int *) buffer;
 	  *buflen = sizeof (session->libc_epfd);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_LIBC_EPFD: libc_epfd %d, "
 			  "buflen %d", getpid (), session->libc_epfd,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_LIBC_EPFD: libc_epfd=%s%d buflen=%d",
 		  .format_args = "t1i4i4",
 		  .n_enum_strings = 2,
 		  .enum_strings = {"", "-",},
 		};
 	      CLIB_PACKED (struct {
 		u8 sign;
 		u32 data[2];
 	      }) * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);

 	      ed->sign = (session->libc_epfd < 0);
 	      ed->data[0] = abs(session->libc_epfd);
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_PROTOCOL:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  *(int *) buffer = session->proto;
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_PROTOCOL: %d (%s), "
 			  "buflen %d", getpid (), *(int *) buffer,
 			  *(int *) buffer ? "UDP" : "TCP", *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_PROTOCOL: %s buflen=%d",
 		  .format_args = "t1i4",
 		  .n_enum_strings = 2,
 		  .enum_strings = {"TCP", "UDP",},
 		};

 	      CLIB_PACKED (struct {
 		u8 proto;
 		u32 buflen;
 	      }) * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->proto = session->proto;
 	      ed->buflen = *(int *) buffer;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_LISTEN:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  *(int *) buffer = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_LISTEN);
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_LISTEN: %d, "
 			  "buflen %d", getpid (), *(int *) buffer, *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_LISTEN: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_ERROR:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  *(int *) buffer = 0;
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_ERROR: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  *(int *) buffer, *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_ERROR: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_TX_FIFO_LEN:
       if (buffer && buflen && (*buflen >= sizeof (u32)))
 	{

 	  /* VPP-TBD */
 	  *(size_t *) buffer = (session->sndbuf_size ? session->sndbuf_size :
 				session->tx_fifo ? session->tx_fifo->nitems :
 				vcm->cfg.tx_fifo_size);
 	  *buflen = sizeof (u32);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_TX_FIFO_LEN: %u (0x%x), "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  *(size_t *) buffer, *(size_t *) buffer, *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_TX_FIFO_LEN: 0x%x buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(size_t *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_TX_FIFO_LEN:
       if (buffer && buflen && (*buflen == sizeof (u32)))
 	{
 	  /* VPP-TBD */
 	  session->sndbuf_size = *(u32 *) buffer;
 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_TX_FIFO_LEN: %u (0x%x), "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  session->sndbuf_size, session->sndbuf_size,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_TX_FIFO_LEN: 0x%x buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = session->sndbuf_size;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_RX_FIFO_LEN:
       if (buffer && buflen && (*buflen >= sizeof (u32)))
 	{

 	  /* VPP-TBD */
 	  *(size_t *) buffer = (session->rcvbuf_size ? session->rcvbuf_size :
 				session->rx_fifo ? session->rx_fifo->nitems :
 				vcm->cfg.rx_fifo_size);
 	  *buflen = sizeof (u32);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_RX_FIFO_LEN: %u (0x%x), "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  *(size_t *) buffer, *(size_t *) buffer, *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_RX_FIFO_LEN: 0x%x buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(size_t *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_RX_FIFO_LEN:
       if (buffer && buflen && (*buflen == sizeof (u32)))
 	{
 	  /* VPP-TBD */
 	  session->rcvbuf_size = *(u32 *) buffer;
 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_RX_FIFO_LEN: %u (0x%x), "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  session->sndbuf_size, session->sndbuf_size,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_RX_FIFO_LEN: 0x%x buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = session->sndbuf_size;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_REUSEADDR:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  *(int *) buffer = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_REUSEADDR);
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_REUSEADDR: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (), *(int *) buffer,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_REUSEADDR: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_REUSEADDR:
       if (buffer && buflen && (*buflen == sizeof (int)) &&
 	  !VCL_SESS_ATTR_TEST (session->attr, VCL_SESS_ATTR_LISTEN))
 	{
 	  /* VPP-TBD */
 	  if (*(int *) buffer)
 	    VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_REUSEADDR);
 	  else
 	    VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_REUSEADDR);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_REUSEADDR: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_REUSEADDR),
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_REUSEADDR: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_REUSEADDR);
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_REUSEPORT:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  *(int *) buffer = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_REUSEPORT);
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_REUSEPORT: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (), *(int *) buffer,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_REUSEPORT: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_REUSEPORT:
       if (buffer && buflen && (*buflen == sizeof (int)) &&
 	  !VCL_SESS_ATTR_TEST (session->attr, VCL_SESS_ATTR_LISTEN))
 	{
 	  /* VPP-TBD */
 	  if (*(int *) buffer)
 	    VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_REUSEPORT);
 	  else
 	    VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_REUSEPORT);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_REUSEPORT: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_REUSEPORT),
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_REUSEPORT: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_REUSEPORT);
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_BROADCAST:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  *(int *) buffer = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_BROADCAST);
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_BROADCAST: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (), *(int *) buffer,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_BROADCAST: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_BROADCAST:
       if (buffer && buflen && (*buflen == sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  if (*(int *) buffer)
 	    VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_BROADCAST);
 	  else
 	    VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_BROADCAST);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_BROADCAST: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_BROADCAST),
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_BROADCAST: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_BROADCAST);
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_V6ONLY:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  *(int *) buffer = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_V6ONLY);
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_V6ONLY: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (), *(int *) buffer,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_V6ONLY: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_V6ONLY:
       if (buffer && buflen && (*buflen == sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  if (*(int *) buffer)
 	    VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_V6ONLY);
 	  else
 	    VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_V6ONLY);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_V6ONLY: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_V6ONLY), *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_V6ONLY: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_V6ONLY);
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_KEEPALIVE:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  *(int *) buffer = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_KEEPALIVE);
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_KEEPALIVE: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (), *(int *) buffer,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_KEEPALIVE: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_KEEPALIVE:
       if (buffer && buflen && (*buflen == sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  if (*(int *) buffer)
 	    VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_KEEPALIVE);
 	  else
 	    VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_KEEPALIVE);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_KEEPALIVE: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_KEEPALIVE),
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_KEEPALIVE: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_KEEPALIVE);
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_TCP_NODELAY:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  *(int *) buffer = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_TCP_NODELAY);
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_TCP_NODELAY: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (), *(int *) buffer,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_TCP_NODELAY: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_TCP_NODELAY:
       if (buffer && buflen && (*buflen == sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  if (*(int *) buffer)
 	    VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_TCP_NODELAY);
 	  else
 	    VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_TCP_NODELAY);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_TCP_NODELAY: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_TCP_NODELAY),
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_TCP_NODELAY: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_TCP_NODELAY);
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_TCP_KEEPIDLE:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  *(int *) buffer = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_TCP_KEEPIDLE);
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_TCP_KEEPIDLE: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (), *(int *) buffer,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_TCP_KEEPIDLE: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_TCP_KEEPIDLE:
       if (buffer && buflen && (*buflen == sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  if (*(int *) buffer)
 	    VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_TCP_KEEPIDLE);
 	  else
 	    VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_TCP_KEEPIDLE);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_TCP_KEEPIDLE: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_TCP_KEEPIDLE),
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_TCP_KEEPIDLE: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_TCP_KEEPIDLE);
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_TCP_KEEPINTVL:
       if (buffer && buflen && (*buflen >= sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  *(int *) buffer = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_TCP_KEEPINTVL);
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_TCP_KEEPINTVL: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (), *(int *) buffer,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_TCP_KEEPIDLE: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_TCP_KEEPINTVL:
       if (buffer && buflen && (*buflen == sizeof (int)))
 	{
 	  /* VPP-TBD */
 	  if (*(int *) buffer)
 	    VCL_SESS_ATTR_SET (session->attr, VCL_SESS_ATTR_TCP_KEEPINTVL);
 	  else
 	    VCL_SESS_ATTR_CLR (session->attr, VCL_SESS_ATTR_TCP_KEEPINTVL);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_TCP_KEEPINTVL: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  VCL_SESS_ATTR_TEST (session->attr,
 					      VCL_SESS_ATTR_TCP_KEEPINTVL),
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_TCP_KEEPINTVL: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = VCL_SESS_ATTR_TEST (session->attr,
 						VCL_SESS_ATTR_TCP_KEEPINTVL);
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_GET_TCP_USER_MSS:
       if (buffer && buflen && (*buflen >= sizeof (u32)))
 	{
 	  /* VPP-TBD */
 	  *(u32 *) buffer = session->user_mss;
 	  *buflen = sizeof (int);

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_GET_TCP_USER_MSS: %d, "
 			  "buflen %d, #VPP-TBD#", getpid (), *(int *) buffer,
 			  *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_GET_TCP_USER_MSS: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = *(int *) buffer;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     case VPPCOM_ATTR_SET_TCP_USER_MSS:
       if (buffer && buflen && (*buflen == sizeof (u32)))
 	{
 	  /* VPP-TBD */
 	  session->user_mss = *(u32 *) buffer;

 	  if (VPPCOM_DEBUG > 2)
 	    clib_warning ("VCL<%d>: VPPCOM_ATTR_SET_TCP_USER_MSS: %u, "
 			  "buflen %d, #VPP-TBD#", getpid (),
 			  session->user_mss, *buflen);
 	  if (VPPCOM_DEBUG > 0)
 	    {
                 /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "VPPCOM_ATTR_SET_TCP_USER_MSS: %d buflen=%d",
 		  .format_args = "i4i4",
 		};

 	      struct {
 		u32 data[2];
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, session->elog_track);
 	      ed->data[0] = session->user_mss;
 	      ed->data[1] = *buflen;
 	      /* *INDENT-ON* */
 	    }
 	}
       else
 	rv = VPPCOM_EINVAL;
       break;

     default:
       rv = VPPCOM_EINVAL;
       break;
     }

 done:
   clib_spinlock_unlock (&vcm->sessions_lockp);
   return rv;
 }

 int
 vppcom_session_recvfrom (uint32_t session_index, void *buffer,
 			 uint32_t buflen, int flags, vppcom_endpt_t * ep)
 {
   int rv = VPPCOM_OK;
   session_t *session = 0;

   if (ep)
     {
       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 ("VCL<%d>: invalid session, "
 			  "sid (%u) has been closed!",
 			  getpid (), session_index);
 	  if (VPPCOM_DEBUG > 0)
 	    {
               /* *INDENT-OFF* */
 	      ELOG_TYPE_DECLARE (e) =
 		{
 		  .format = "invalid session: %d closed",
 		  .format_args = "i4",
 		};

 	      struct {
 		u32 data;
 	      } * ed;

 	      ed = ELOG_TRACK_DATA (&vcm->elog_main, e, vcm->elog_track);
 	      ed->data = session_index;
 	      /* *INDENT-ON* */
 	    }
 	  rv = VPPCOM_EBADFD;
 	  clib_spinlock_unlock (&vcm->sessions_lockp);
 	  goto done;
 	}
       ep->is_ip4 = session->peer_addr.is_ip4;
       ep->port = session->peer_port;
       if (session->peer_addr.is_ip4)
 	clib_memcpy (ep->ip, &session->peer_addr.ip46.ip4,
 		     sizeof (ip4_address_t));
       else
 	clib_memcpy (ep->ip, &session->peer_addr.ip46.ip6,
 		     sizeof (ip6_address_t));
       clib_spinlock_unlock (&vcm->sessions_lockp);
     }

   if (flags == 0)
     rv = vppcom_session_read (session_index, buffer, buflen);
   else if (flags & MSG_PEEK)
     rv = vppcom_session_peek (session_index, buffer, buflen);
   else
     {
       clib_warning ("VCL<%d>: Unsupport flags for recvfrom %d",
 		    getpid (), flags);
       rv = VPPCOM_EAFNOSUPPORT;
     }

 done:
   return rv;
 }

 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 VPPCOM_EINVAL;
     }

   if (flags)
     {
       // TBD check the flags and do the right thing
       if (VPPCOM_DEBUG > 2)
 	clib_warning ("VCL<%d>: handling flags 0x%u (%d) "
 		      "not implemented yet.", getpid (), flags, flags);
     }

   return (vppcom_session_write (session_index, buffer, buflen));
 }

 int
 vppcom_poll (vcl_poll_t * vp, uint32_t n_sids, double wait_for_time)
 {
   f64 timeout = clib_time_now (&vcm->clib_time) + wait_for_time;
   u32 i, keep_trying = 1;
   int rv, num_ev = 0;

   if (VPPCOM_DEBUG > 3)
     clib_warning ("VCL<%d>: vp %p, nsids %u, wait_for_time %f",
 		  getpid (), vp, n_sids, wait_for_time);

   if (!vp)
     return VPPCOM_EFAULT;

   do
     {
       session_t *session;

       for (i = 0; i < n_sids; i++)
 	{
 	  ASSERT (vp[i].revents);

 	  VCL_LOCK_AND_GET_SESSION (vp[i].sid, &session);
 	  clib_spinlock_unlock (&vcm->sessions_lockp);

 	  if (*vp[i].revents)
 	    *vp[i].revents = 0;

 	  if (POLLIN & vp[i].events)
 	    {
 	      VCL_LOCK_AND_GET_SESSION (vp[i].sid, &session);
 	      rv = vppcom_session_read_ready (session, vp[i].sid);
 	      clib_spinlock_unlock (&vcm->sessions_lockp);
 	      if (rv > 0)
 		{
 		  *vp[i].revents |= POLLIN;
 		  num_ev++;
 		}
 	      else if (rv < 0)
 		{
 		  switch (rv)
 		    {
 		    case VPPCOM_ECONNRESET:
 		      *vp[i].revents = POLLHUP;
 		      break;

 		    default:
 		      *vp[i].revents = POLLERR;
 		      break;
 		    }
 		  num_ev++;
 		}
 	    }

 	  if (POLLOUT & vp[i].events)
 	    {
 	      VCL_LOCK_AND_GET_SESSION (vp[i].sid, &session);
 	      rv = vppcom_session_write_ready (session, vp[i].sid);
 	      clib_spinlock_unlock (&vcm->sessions_lockp);
 	      if (rv > 0)
 		{
 		  *vp[i].revents |= POLLOUT;
 		  num_ev++;
 		}
 	      else if (rv < 0)
 		{
 		  switch (rv)
 		    {
 		    case VPPCOM_ECONNRESET:
 		      *vp[i].revents = POLLHUP;
 		      break;

 		    default:
 		      *vp[i].revents = POLLERR;
 		      break;
 		    }
 		  num_ev++;
 		}
 	    }

 	  if (0)		// Note "done:" label used by VCL_LOCK_AND_GET_SESSION()
 	    {
 	    done:
 	      *vp[i].revents = POLLNVAL;
 	      num_ev++;
 	    }
 	}
       if (wait_for_time != -1)
 	keep_trying = (clib_time_now (&vcm->clib_time) <= timeout) ? 1 : 0;
     }
   while ((num_ev == 0) && keep_trying);

   if (VPPCOM_DEBUG > 3)
     {
       clib_warning ("VCL<%d>: returning %d", getpid (), num_ev);
       for (i = 0; i < n_sids; i++)
 	{
 	  clib_warning ("VCL<%d>: vp[%d].sid %d (0x%x), .events 0x%x, "
 			".revents 0x%x", getpid (), i, vp[i].sid, vp[i].sid,
 			vp[i].events, *vp[i].revents);
 	}
     }
   return num_ev;
 }

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */