udp: fix connections move

Without this the use of uc0 is racy between the current thread and the
thread that owns it and will delete it.

This also ensures we don't trigger a read event on the session before
moving it to the right thread and notifying the application.

Type: fix
Change-Id: Icb1ca3ee5805ea3c0d2d424d4b23511465deb3b6
Signed-off-by: Aloys Augustin <aloaugus@cisco.com>

diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index 3d22cc2..33f1e26 100644 (file)
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -565,6 +565,31 @@ session_enqueue_notify (session_t * s)
   return session_enqueue_notify_inline (s);
 }
 
+static void
+session_enqueue_notify_rpc (void *arg)
+{
+  session_handle_t sh = (session_handle_t) arg;
+  session_t *s;
+
+  s = session_get_from_handle_if_valid (sh);
+  if (!s)
+    return;
+
+  session_enqueue_notify (s);
+}
+
+/**
+ * Like session_enqueue_notify, but can be called from a thread that does not
+ * own the session.
+ */
+void
+session_enqueue_notify_thread (session_handle_t sh)
+{
+  u32 thread_index = session_thread_from_handle (sh);
+  session_send_rpc_evt_to_thread (thread_index,
+                                 session_enqueue_notify_rpc, (void *) sh);
+}
+
 int
 session_dequeue_notify (session_t * s)
 {
@@ -739,6 +764,9 @@ session_switch_pool (void *cb_args)
       new_sh = session_make_handle (args->new_session_index,
                                    args->new_thread_index);
       app_worker_migrate_notify (app_wrk, s, new_sh);
+
+      /* Trigger app read on the new thread */
+      session_enqueue_notify_thread (new_sh);
     }
 
   session_free (s);

diff --git a/src/vnet/udp/udp_input.c b/src/vnet/udp/udp_input.c
index 936d94d..ad86f43 100644 (file)
--- a/src/vnet/udp/udp_input.c
+++ b/src/vnet/udp/udp_input.c
@@ -110,6 +110,7 @@ udp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
          int wrote0;
          void *rmt_addr, *lcl_addr;
          session_dgram_hdr_t hdr0;
+         u8 queue_event = 1;
 
          /* speculatively enqueue b0 to the current next frame */
          bi0 = from[0];
@@ -182,6 +183,8 @@ udp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
                      session_dgram_connect_notify (&new_uc0->connection,
                                                    s0->thread_index, &s0);
                      tc0 = &new_uc0->connection;
+                     uc0 = new_uc0;
+                     queue_event = 0;
                    }
                  else
                    s0->session_state = SESSION_STATE_READY;
@@ -254,7 +257,7 @@ udp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
          clib_spinlock_lock (&uc0->rx_lock);
          wrote0 = session_enqueue_dgram_connection (s0, &hdr0, b0,
                                                     TRANSPORT_PROTO_UDP,
-                                                    1 /* queue evt */ );
+                                                    queue_event);
          clib_spinlock_unlock (&uc0->rx_lock);
          ASSERT (wrote0 > 0);