vcl: basic support for apps that fork

- intercept fork and register a new worker with vpp
- share sessions between parent and forked child
- keep binary api state per worker

Change-Id: Ib177517d661724fa042bd2d98d18e777056352a2
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 138 insertions, 117 deletions

diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 589d57c3872..195e6cbc602 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -423,7 +423,7 @@ vcl_session_reset_handler (vcl_worker_t * wrk,
   session->session_state = STATE_CLOSE_ON_EMPTY;
   VDBG (0, "reset handle 0x%llx, sid %u ", reset_msg->handle, sid);
   vcl_send_session_reset_reply (vcl_session_vpp_evt_q (wrk, session),
-				vcm->my_client_index, reset_msg->handle, 0);
+				wrk->my_client_index, reset_msg->handle, 0);
   return sid;
 }
 
@@ -673,7 +673,7 @@ vppcom_session_disconnect (u32 session_handle)
   if (state & STATE_CLOSE_ON_EMPTY)
     {
       vpp_evt_q = vcl_session_vpp_evt_q (wrk, session);
-      vcl_send_session_disconnected_reply (vpp_evt_q, vcm->my_client_index,
+      vcl_send_session_disconnected_reply (vpp_evt_q, wrk->my_client_index,
 					   vpp_handle, 0);
       VDBG (1, "VCL<%d>: vpp handle 0x%llx, sid %u: sending disconnect "
 	    "REPLY...", getpid (), vpp_handle, session_handle);
@@ -691,12 +691,14 @@ vppcom_session_disconnect (u32 session_handle)
 static void
 vcl_cleanup_bapi (void)
 {
+  socket_client_main_t *scm = &socket_client_main;
   api_main_t *am = &api_main;
 
   am->my_client_index = ~0;
   am->my_registration = 0;
   am->vl_input_queue = 0;
   am->msg_index_by_name_and_crc = 0;
+  scm->socket_fd = 0;
 
   vl_client_api_unmap ();
 }
@@ -705,14 +707,22 @@ void
 vcl_app_fork_child_handler (void)
 {
   u8 *child_name;
-  int rv;
-
-  vcm->current_pid = getpid ();
-  vcl_set_worker_index (0);
+  int rv, parent_wrk;
 
   VDBG (0, "initializing forked child");
-  child_name = format (0, "%v-child-%u%c", vcm->app_name, getpid (), 0);
 
+  /*
+   * Allocate worker
+   */
+  parent_wrk = vcl_get_worker_index ();
+  vcl_set_worker_index (~0);
+  if (!vcl_worker_alloc_and_init ())
+    VERR ("couldn't allocate new worker");
+
+  /*
+   * Attach to binary api
+   */
+  child_name = format (0, "%v-child-%u%c", vcm->app_name, getpid (), 0);
   vcl_cleanup_bapi ();
   vppcom_api_hookup ();
   vcm->app_state = STATE_APP_START;
@@ -724,14 +734,23 @@ vcl_app_fork_child_handler (void)
       return;
     }
 
-  vcm->app_state = STATE_APP_ADDING_WORKER;
-  vcl_send_app_worker_add_del (1 /* is_add */ );
-  if (vcl_wait_for_app_state_change (STATE_APP_READY))
-    {
-      VERR ("failed to add worker to vpp");
-      return;
-    }
+  /*
+   * Register worker with vpp and share sessions
+   */
+  vcl_worker_register_with_vpp ();
+  vcl_worker_share_sessions (parent_wrk);
+
   VDBG (0, "forked child main worker initialized");
+  vcm->forking = 0;
+}
+
+void
+vcl_app_fork_parent_handler (void)
+{
+  vcm->forking = 1;
+
+  while (vcm->forking)
+    ;
 }
 
 /*
@@ -743,55 +762,58 @@ vppcom_app_create (char *app_name)
   vppcom_cfg_t *vcl_cfg = &vcm->cfg;
   int rv;
 
-  if (!vcm->is_init)
+  if (vcm->is_init)
     {
-      vcm->is_init = 1;
-      vppcom_cfg (&vcm->cfg);
-      vcl_cfg = &vcm->cfg;
-
-      vcm->main_cpu = pthread_self ();
-      vcm->main_pid = vcm->current_pid = getpid ();
-      vcm->app_name = format (0, "%s", app_name);
-      vppcom_init_error_string_table ();
-      svm_fifo_segment_main_init (vcl_cfg->segment_baseva,
-				  20 /* timeout in secs */ );
-      pool_init_fixed (vcm->workers, vcl_cfg->max_workers);
-      clib_spinlock_init (&vcm->workers_lock);
-      vcl_worker_alloc_and_init ();
-      pthread_atfork (NULL, NULL, vcl_app_fork_child_handler);
+      clib_warning ("already initialized");
+      return -1;
     }
 
-  if (vcm->my_client_index == ~0)
-    {
-      /* API hookup and connect to VPP */
-      vppcom_api_hookup ();
-      vcl_elog_init (vcm);
-      vcm->app_state = STATE_APP_START;
-      rv = vppcom_connect_to_vpp (app_name);
-      if (rv)
-	{
-	  VERR ("couldn't connect to VPP!");
-	  return rv;
-	}
-      VDBG (0, "sending session enable");
-      rv = vppcom_app_session_enable ();
-      if (rv)
-	{
-	  VERR ("vppcom_app_session_enable() failed!");
-	  return rv;
-	}
+  vcm->is_init = 1;
+  vppcom_cfg (&vcm->cfg);
+  vcl_cfg = &vcm->cfg;
 
-      VDBG (0, "sending app attach");
-      rv = vppcom_app_attach ();
-      if (rv)
-	{
-	  VERR ("vppcom_app_attach() failed!");
-	  return rv;
-	}
+  vcm->main_cpu = pthread_self ();
+  vcm->main_pid = getpid ();
+  vcm->app_name = format (0, "%s", app_name);
+  vppcom_init_error_string_table ();
+  svm_fifo_segment_main_init (vcl_cfg->segment_baseva,
+			      20 /* timeout in secs */ );
+  pool_alloc (vcm->workers, vcl_cfg->max_workers);
+  clib_spinlock_init (&vcm->workers_lock);
+  pthread_atfork (NULL, vcl_app_fork_parent_handler,
+		  vcl_app_fork_child_handler);
 
-      VDBG (0, "app_name '%s', my_client_index %d (0x%x)",
-	    app_name, vcm->my_client_index, vcm->my_client_index);
+  /* Allocate default worker */
+  vcl_worker_alloc_and_init ();
+
+  /* API hookup and connect to VPP */
+  vppcom_api_hookup ();
+  vcl_elog_init (vcm);
+  vcm->app_state = STATE_APP_START;
+  rv = vppcom_connect_to_vpp (app_name);
+  if (rv)
+    {
+      VERR ("couldn't connect to VPP!");
+      return rv;
     }
+  VDBG (0, "sending session enable");
+  rv = vppcom_app_session_enable ();
+  if (rv)
+    {
+      VERR ("vppcom_app_session_enable() failed!");
+      return rv;
+    }
+
+  VDBG (0, "sending app attach");
+  rv = vppcom_app_attach ();
+  if (rv)
+    {
+      VERR ("vppcom_app_attach() failed!");
+      return rv;
+    }
+
+  VDBG (0, "app_name '%s', my_client_index %d (0x%x)", app_name,
+	vcm->workers[0].my_client_index, vcm->workers[0].my_client_index);
 
   return VPPCOM_OK;
 }
@@ -802,27 +824,27 @@ vppcom_app_destroy (void)
   int rv;
   f64 orig_app_timeout;
 
-  if (vcm->my_client_index == ~0)
-    return;
-
-  VDBG (0, "detaching from VPP, my_client_index %d (0x%x)",
-	vcm->my_client_index, vcm->my_client_index);
   vcl_evt (VCL_EVT_DETACH, vcm);
 
-  vppcom_app_send_detach ();
-  orig_app_timeout = vcm->cfg.app_timeout;
-  vcm->cfg.app_timeout = 2.0;
-  rv = vcl_wait_for_app_state_change (STATE_APP_ENABLED);
-  vcm->cfg.app_timeout = orig_app_timeout;
-  if (PREDICT_FALSE (rv))
-    VDBG (0, "application detach timed out! returning %d (%s)",
-	  rv, vppcom_retval_str (rv));
+  if (vec_len (vcm->workers) == 1)
+    {
+      vppcom_app_send_detach ();
+      orig_app_timeout = vcm->cfg.app_timeout;
+      vcm->cfg.app_timeout = 2.0;
+      rv = vcl_wait_for_app_state_change (STATE_APP_ENABLED);
+      vcm->cfg.app_timeout = orig_app_timeout;
+      if (PREDICT_FALSE (rv))
+	VDBG (0, "application detach timed out! returning %d (%s)", rv,
+	      vppcom_retval_str (rv));
+    }
+  else
+    {
+      vcl_worker_cleanup ();
+    }
 
   vcl_elog_stop (vcm);
   vl_client_disconnect_from_vlib ();
   vec_free (vcm->app_name);
-  vcm->my_client_index = ~0;
-  vcm->app_state = STATE_APP_START;
 }
 
 int
@@ -853,8 +875,8 @@ int
 vppcom_session_close (uint32_t session_handle)
 {
   vcl_worker_t *wrk = vcl_worker_get_current ();
+  u8 is_vep, do_disconnect = 1;
   vcl_session_t *session = 0;
-  u8 is_vep, is_vep_session;
   session_state_t state;
   u32 next_sh, vep_sh;
   int rv = VPPCOM_OK;
@@ -864,24 +886,17 @@ vppcom_session_close (uint32_t session_handle)
   if (!session)
     return VPPCOM_EBADFD;
 
+  if (session->shared_index != ~0)
+    do_disconnect = vcl_worker_unshare_session (wrk, session);
+
   is_vep = session->is_vep;
-  is_vep_session = session->is_vep_session;
   next_sh = session->vep.next_sh;
   vep_sh = session->vep.vep_sh;
   state = session->session_state;
   vpp_handle = session->vpp_handle;
 
-  if (VPPCOM_DEBUG > 0)
-    {
-      if (is_vep)
-	clib_warning ("VCL<%d>: vep_idx %u / sid %u: "
-		      "closing epoll session...",
-		      getpid (), session_handle, session_handle);
-      else
-	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %d: "
-		      "closing session...",
-		      getpid (), vpp_handle, session_handle);
-    }
+  VDBG (0, "Closing session handle %u vpp handle %u", session_handle,
+	vpp_handle);
 
   if (is_vep)
     {
@@ -889,34 +904,34 @@ vppcom_session_close (uint32_t session_handle)
 	{
 	  rv = vppcom_epoll_ctl (session_handle, EPOLL_CTL_DEL, next_sh, 0);
 	  if (PREDICT_FALSE (rv < 0))
-	    VDBG (0, "VCL<%d>: vpp handle 0x%llx, sid %u: EPOLL_CTL_DEL "
-		  "vep_idx %u failed! rv %d (%s)",
-		  getpid (), vpp_handle, next_sh, vep_sh,
-		  rv, vppcom_retval_str (rv));
+	    VDBG (0, "vpp handle 0x%llx, sid %u: EPOLL_CTL_DEL vep_idx %u"
+		  " failed! rv %d (%s)", vpp_handle, next_sh, vep_sh, rv,
+		  vppcom_retval_str (rv));
 
 	  next_sh = session->vep.next_sh;
 	}
     }
   else
     {
-      if (is_vep_session)
+      if (session->is_vep_session)
 	{
 	  rv = vppcom_epoll_ctl (vep_sh, EPOLL_CTL_DEL, session_handle, 0);
 	  if (rv < 0)
-	    VDBG (0, "VCL<%d>: vpp handle 0x%llx, sid %u: EPOLL_CTL_DEL "
-		  "vep_idx %u failed! rv %d (%s)",
-		  getpid (), vpp_handle, session_handle,
-		  vep_sh, rv, vppcom_retval_str (rv));
+	    VDBG (0, "vpp handle 0x%llx, sid %u: EPOLL_CTL_DEL vep_idx %u "
+		  "failed! rv %d (%s)", vpp_handle, session_handle, vep_sh,
+		  rv, vppcom_retval_str (rv));
 	}
 
+      if (!do_disconnect)
+	goto cleanup;
+
       if (state & STATE_LISTEN)
 	{
 	  rv = vppcom_session_unbind (session_handle);
 	  if (PREDICT_FALSE (rv < 0))
-	    VDBG (0, "VCL<%d>: vpp handle 0x%llx, sid %u: listener unbind "
-		  "failed! rv %d (%s)",
-		  getpid (), vpp_handle, session_handle,
-		  rv, vppcom_retval_str (rv));
+	    VDBG (0, "vpp handle 0x%llx, sid %u: listener unbind failed! "
+		  "rv %d (%s)", vpp_handle, session_handle, rv,
+		  vppcom_retval_str (rv));
 	}
       else if (state & STATE_OPEN)
 	{
@@ -929,6 +944,8 @@ vppcom_session_close (uint32_t session_handle)
 	}
     }
 
+cleanup:
+
   if (vcl_session_is_ct (session))
     {
       vcl_cut_through_registration_t *ctr;
@@ -952,15 +969,8 @@ vppcom_session_close (uint32_t session_handle)
     }
   vcl_session_free (wrk, session);
 
-  if (VPPCOM_DEBUG > 0)
-    {
-      if (is_vep)
-	clib_warning ("VCL<%d>: vep_idx %u / sid %u: epoll session removed.",
-		      getpid (), session_handle, session_handle);
-      else
-	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: session removed.",
-		      getpid (), vpp_handle, session_handle);
-    }
+  VDBG (0, "session handle %u vpp handle %u removed", session_handle,
+	vpp_handle);
 
   vcl_evt (VCL_EVT_CLOSE, session, rv);
 
@@ -1986,9 +1996,9 @@ vppcom_select (unsigned long n_bits, unsigned long *read_map,
   clib_bitmap_foreach (sid, wrk->wr_bitmap, ({
     if (!(session = vcl_session_get (wrk, sid)))
       {
-        VDBG (0, "VCL<%d>: session %d specified in write_map is closed.",
-              getpid (), sid);
-        return VPPCOM_EBADFD;
+        if (except_map && sid < minbits)
+          clib_bitmap_set_no_check (except_map, sid, 1);
+        continue;
       }
 
     rv = svm_fifo_is_full (session->tx_fifo);
@@ -2006,9 +2016,9 @@ check_rd:
   clib_bitmap_foreach (sid, wrk->rd_bitmap, ({
     if (!(session = vcl_session_get (wrk, sid)))
       {
-        VDBG (0, "VCL<%d>: session %d specified in write_map is closed.",
-              getpid (), sid);
-        return VPPCOM_EBADFD;
+        if (except_map && sid < minbits)
+          clib_bitmap_set_no_check (except_map, sid, 1);
+        continue;
       }
 
     rv = vppcom_session_read_ready (session);
@@ -3150,6 +3160,10 @@ vppcom_session_attr (uint32_t session_handle, uint32_t op,
 	rv = VPPCOM_EINVAL;
       break;
 
+    case VPPCOM_ATTR_GET_REFCNT:
+      rv = vcl_session_get_refcnt (session);
+      break;
+
     default:
       rv = VPPCOM_EINVAL;
       break;
@@ -3355,15 +3369,22 @@ vppcom_session_index (uint32_t session_handle)
 int
 vppcom_session_handle (uint32_t session_index)
 {
-  return vcl_get_worker_index () << 24 | session_index;
+  return (vcl_get_worker_index () << 24) | session_index;
 }
 
 int
 vppcom_worker_register (void)
 {
-  if (vcl_worker_alloc_and_init ())
-    return VPPCOM_OK;
-  return VPPCOM_EEXIST;
+  if (!vcl_worker_alloc_and_init ())
+    return VPPCOM_EEXIST;
+
+  if (vcl_worker_set_bapi ())
+    return VPPCOM_EEXIST;
+
+  if (vcl_worker_register_with_vpp ())
+    return VPPCOM_EEXIST;
+
+  return VPPCOM_OK;
 }
 
 int