vcl: add support for reconnect

Supported only when eventfd option is enabled.

Type: feature

Change-Id: Ic9d6e38604e978f7bc8e54d74fe9b8f3fc53622d
Signed-off-by: Filip Tehlar <ftehlar@cisco.com>

4 files changed, 127 insertions, 1 deletions

diff --git a/src/vcl/vcl_private.c b/src/vcl/vcl_private.c
index d12d2d31a8f..b6ef815b53d 100644
--- a/src/vcl/vcl_private.c
+++ b/src/vcl/vcl_private.c
@@ -38,6 +38,25 @@ vcl_mq_evt_conn_get (vcl_worker_t * wrk, u32 mq_conn_idx)
   return pool_elt_at_index (wrk->mq_evt_conns, mq_conn_idx);
 }
 
+/* Add unix socket to epoll.
+ * Used only to get a notification on socket close
+ * We can't use eventfd because we don't get notifications on that fds
+ */
+static int
+vcl_mq_epoll_add_api_sock (vcl_worker_t *wrk)
+{
+  clib_socket_t *cs = &wrk->app_api_sock;
+  struct epoll_event e = { 0 };
+  int rv;
+
+  e.data.u32 = ~0;
+  rv = epoll_ctl (wrk->mqs_epfd, EPOLL_CTL_ADD, cs->fd, &e);
+  if (rv != EEXIST && rv < 0)
+    return -1;
+
+  return 0;
+}
+
 int
 vcl_mq_epoll_add_evfd (vcl_worker_t * wrk, svm_msg_q_t * mq)
 {
@@ -64,6 +83,12 @@ vcl_mq_epoll_add_evfd (vcl_worker_t * wrk, svm_msg_q_t * mq)
       return -1;
     }
 
+  if (vcl_mq_epoll_add_api_sock (wrk))
+    {
+      VDBG (0, "failed to add mq socket to mq epoll fd");
+      return -1;
+    }
+
   return mqc_index;
 }
 
@@ -158,6 +183,33 @@ vcl_worker_cleanup_cb (void *arg)
   VDBG (0, "cleaned up worker %u", wrk_index);
 }
 
+void
+vcl_worker_detach_sessions (vcl_worker_t *wrk)
+{
+  session_event_t *e;
+  vcl_session_t *s;
+
+  close (wrk->app_api_sock.fd);
+  pool_foreach (s, wrk->sessions)
+    {
+      if (s->session_state == VCL_STATE_LISTEN)
+	{
+	  s->session_state = VCL_STATE_LISTEN_NO_MQ;
+	  continue;
+	}
+      if (s->flags & VCL_SESSION_F_IS_VEP)
+	continue;
+
+      s->session_state = VCL_STATE_DETACHED;
+      vec_add2 (wrk->unhandled_evts_vector, e, 1);
+      e->event_type = SESSION_CTRL_EVT_DISCONNECTED;
+      e->session_index = s->session_index;
+      e->postponed = 1;
+    }
+
+  vcl_segment_detach_all ();
+}
+
 vcl_worker_t *
 vcl_worker_alloc_and_init ()
 {
@@ -410,6 +462,24 @@ vcl_segment_detach (u64 segment_handle)
   VDBG (0, "detached segment %u handle %u", segment_index, segment_handle);
 }
 
+void
+vcl_segment_detach_all ()
+{
+  u64 *segs = 0, *seg, key;
+  u32 val;
+
+  clib_rwlock_reader_lock (&vcm->segment_table_lock);
+
+  hash_foreach (key, val, vcm->segment_table, ({ vec_add1 (segs, key); }));
+
+  clib_rwlock_reader_unlock (&vcm->segment_table_lock);
+
+  vec_foreach (seg, segs)
+    vcl_segment_detach (seg[0]);
+
+  vec_free (segs);
+}
+
 int
 vcl_segment_attach_session (uword segment_handle, uword rxf_offset,
 			    uword txf_offset, uword mq_offset, u32 mq_index,
diff --git a/src/vcl/vcl_private.h b/src/vcl/vcl_private.h
index f163de20125..e4f1c149b2d 100644
--- a/src/vcl/vcl_private.h
+++ b/src/vcl/vcl_private.h
@@ -716,6 +716,7 @@ int vcl_send_worker_rpc (u32 dst_wrk_index, void *data, u32 data_len);
 int vcl_segment_attach (u64 segment_handle, char *name,
 			ssvm_segment_type_t type, int fd);
 void vcl_segment_detach (u64 segment_handle);
+void vcl_segment_detach_all ();
 void vcl_send_session_unlisten (vcl_worker_t * wrk, vcl_session_t * s);
 
 int vcl_segment_attach_session (uword segment_handle, uword rxf_offset,
@@ -729,6 +730,7 @@ svm_fifo_chunk_t *vcl_segment_alloc_chunk (uword segment_handle,
 					   uword *offset);
 int vcl_session_share_fifos (vcl_session_t *s, svm_fifo_t *rxf,
 			     svm_fifo_t *txf);
+void vcl_worker_detach_sessions (vcl_worker_t *wrk);
 
 /*
  * VCL Binary API
diff --git a/src/vcl/vcl_sapi.c b/src/vcl/vcl_sapi.c
index 981257ede8d..870a634db8c 100644
--- a/src/vcl/vcl_sapi.c
+++ b/src/vcl/vcl_sapi.c
@@ -30,7 +30,9 @@ vcl_api_connect_app_socket (vcl_worker_t * wrk)
 
   if ((err = clib_socket_init (cs)))
     {
-      clib_error_report (err);
+      /* don't report the error to avoid flood of error messages during
+       * reconnect */
+      clib_error_free (err);
       rv = -1;
       goto done;
     }
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 4a6c46b3f3b..0e81749224e 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -1257,6 +1257,33 @@ vcl_api_attach (void)
 }
 
 static void
+vcl_api_retry_attach (vcl_worker_t *wrk)
+{
+  vcl_session_t *s;
+
+  if (vcl_api_attach ())
+    return;
+
+  /* Treat listeners as configuration that needs to be re-added to vpp */
+  pool_foreach (s, wrk->sessions)
+    {
+      if (s->flags & VCL_SESSION_F_IS_VEP)
+	continue;
+      if (s->session_state == VCL_STATE_LISTEN_NO_MQ)
+	vppcom_session_listen (vcl_session_handle (s), 10);
+      else
+	VDBG (0, "internal error: unexpected state %d", s->session_state);
+    }
+}
+
+static void
+vcl_api_handle_disconnect (vcl_worker_t *wrk)
+{
+  wrk->api_client_handle = ~0;
+  vcl_worker_detach_sessions (wrk);
+}
+
+static void
 vcl_api_detach (vcl_worker_t * wrk)
 {
   vcl_send_app_detach (wrk);
@@ -2468,11 +2495,23 @@ vppcom_select_eventfd (vcl_worker_t * wrk, int n_bits,
   int n_mq_evts, i;
   u64 buf;
 
+  if (PREDICT_FALSE (wrk->api_client_handle == ~0))
+    {
+      vcl_api_retry_attach (wrk);
+      return 0;
+    }
+
   vec_validate (wrk->mq_events, pool_elts (wrk->mq_evt_conns));
   n_mq_evts = epoll_wait (wrk->mqs_epfd, wrk->mq_events,
 			  vec_len (wrk->mq_events), time_to_wait);
   for (i = 0; i < n_mq_evts; i++)
     {
+      if (PREDICT_FALSE (wrk->mq_events[i].data.u32 == ~0))
+	{
+	  vcl_api_handle_disconnect (wrk);
+	  continue;
+	}
+
       mqc = vcl_mq_evt_conn_get (wrk, wrk->mq_events[i].data.u32);
       n_read = read (mqc->mq_fd, &buf, sizeof (buf));
       vcl_select_handle_mq (wrk, mqc->mq, n_bits, read_map, write_map,
@@ -3189,6 +3228,12 @@ vppcom_epoll_wait_eventfd (vcl_worker_t *wrk, struct epoll_event *events,
   double end = -1;
   u64 buf;
 
+  if (PREDICT_FALSE (wrk->api_client_handle == ~0))
+    {
+      vcl_api_retry_attach (wrk);
+      return n_evts;
+    }
+
   vec_validate (wrk->mq_events, pool_elts (wrk->mq_evt_conns));
   if (!n_evts)
     {
@@ -3208,6 +3253,13 @@ vppcom_epoll_wait_eventfd (vcl_worker_t *wrk, struct epoll_event *events,
 
       for (i = 0; i < n_mq_evts; i++)
 	{
+	  if (PREDICT_FALSE (wrk->mq_events[i].data.u32 == ~0))
+	    {
+	      /* api socket was closed */
+	      vcl_api_handle_disconnect (wrk);
+	      continue;
+	    }
+
 	  mqc = vcl_mq_evt_conn_get (wrk, wrk->mq_events[i].data.u32);
 	  n_read = read (mqc->mq_fd, &buf, sizeof (buf));
 	  vcl_epoll_wait_handle_mq (wrk, mqc->mq, events, maxevents, 0,