session: support half-close connection

Some app(e.g. Envoy) may call shutdown() instead of close() when
draining connection.

Type: improvement

Signed-off-by: liuyacan <liuyacan@corp.netease.com>
Change-Id: I9543b9ca3caa87b10b134fd1fc4019124e41e4d2

6 files changed, 78 insertions, 1 deletions

diff --git a/src/vcl/ldp.c b/src/vcl/ldp.c
index 64a4e7c77db..f27f6ba8e97 100644
--- a/src/vcl/ldp.c
+++ b/src/vcl/ldp.c
@@ -2219,6 +2219,8 @@ shutdown (int fd, int how)
 
       if (flags == SHUT_RDWR)
 	rv = close (fd);
+      else if (flags == SHUT_WR)
+	rv = vls_shutdown (vlsh);
     }
   else
     {
diff --git a/src/vcl/vcl_locked.c b/src/vcl/vcl_locked.c
index 757c0fc45a7..69f492b8694 100644
--- a/src/vcl/vcl_locked.c
+++ b/src/vcl/vcl_locked.c
@@ -1313,6 +1313,24 @@ vls_close (vls_handle_t vlsh)
   return rv;
 }
 
+int
+vls_shutdown (vls_handle_t vlsh)
+{
+  vcl_locked_session_t *vls;
+  int rv;
+
+  vls_mt_detect ();
+  if (!(vls = vls_get_w_dlock (vlsh)))
+    return VPPCOM_EBADFD;
+
+  vls_mt_guard (vls, VLS_MT_OP_SPOOL);
+  rv = vppcom_session_shutdown (vls_to_sh (vls));
+  vls_mt_unguard ();
+  vls_get_and_unlock (vlsh);
+
+  return rv;
+}
+
 vls_handle_t
 vls_epoll_create (void)
 {
diff --git a/src/vcl/vcl_locked.h b/src/vcl/vcl_locked.h
index 11b71eee4af..3adcf62bc77 100644
--- a/src/vcl/vcl_locked.h
+++ b/src/vcl/vcl_locked.h
@@ -26,6 +26,7 @@
 typedef int vls_handle_t;
 
 vls_handle_t vls_create (uint8_t proto, uint8_t is_nonblocking);
+int vls_shutdown (vls_handle_t vlsh);
 int vls_close (vls_handle_t vlsh);
 int vls_bind (vls_handle_t vlsh, vppcom_endpt_t * ep);
 int vls_listen (vls_handle_t vlsh, int q_len);
diff --git a/src/vcl/vcl_private.h b/src/vcl/vcl_private.h
index 6060ef82357..956f077b880 100644
--- a/src/vcl/vcl_private.h
+++ b/src/vcl/vcl_private.h
@@ -137,6 +137,7 @@ typedef enum vcl_session_flags_
   VCL_SESSION_F_IS_VEP = 1 << 1,
   VCL_SESSION_F_IS_VEP_SESSION = 1 << 2,
   VCL_SESSION_F_HAS_RX_EVT = 1 << 3,
+  VCL_SESSION_F_SHUTDOWN = 1 << 4,
 } __clib_packed vcl_session_flags_t;
 
 typedef struct vcl_session_
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 96a207b741f..0713a7b2d33 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -260,6 +260,23 @@ vcl_send_session_unlisten (vcl_worker_t * wrk, vcl_session_t * s)
 }
 
 static void
+vcl_send_session_shutdown (vcl_worker_t *wrk, vcl_session_t *s)
+{
+  app_session_evt_t _app_evt, *app_evt = &_app_evt;
+  session_shutdown_msg_t *mp;
+  svm_msg_q_t *mq;
+
+  /* Send to thread that owns the session */
+  mq = s->vpp_evt_q;
+  app_alloc_ctrl_evt_to_vpp (mq, app_evt, SESSION_CTRL_EVT_SHUTDOWN);
+  mp = (session_shutdown_msg_t *) app_evt->evt->data;
+  memset (mp, 0, sizeof (*mp));
+  mp->client_index = wrk->api_client_handle;
+  mp->handle = s->vpp_handle;
+  app_send_ctrl_evt_to_vpp (mq, app_evt);
+}
+
+static void
 vcl_send_session_disconnect (vcl_worker_t * wrk, vcl_session_t * s)
 {
   app_session_evt_t _app_evt, *app_evt = &_app_evt;
@@ -789,6 +806,42 @@ vcl_session_disconnected_handler (vcl_worker_t * wrk,
   return session;
 }
 
+int
+vppcom_session_shutdown (uint32_t session_handle)
+{
+  vcl_worker_t *wrk = vcl_worker_get_current ();
+  vcl_session_t *session;
+  vcl_session_state_t state;
+  u64 vpp_handle;
+
+  session = vcl_session_get_w_handle (wrk, session_handle);
+  if (PREDICT_FALSE (!session))
+    return VPPCOM_EBADFD;
+
+  vpp_handle = session->vpp_handle;
+  state = session->session_state;
+
+  VDBG (1, "session %u [0x%llx] state 0x%x (%s)", session->session_index,
+	vpp_handle, state, vppcom_session_state_str (state));
+
+  if (PREDICT_FALSE (state == VCL_STATE_LISTEN))
+    {
+      VDBG (0, "ERROR: Cannot shutdown a listen socket!");
+      return VPPCOM_EBADFD;
+    }
+
+  if (PREDICT_TRUE (state == VCL_STATE_READY))
+    {
+      VDBG (1, "session %u [0x%llx]: sending shutdown...",
+	    session->session_index, vpp_handle);
+
+      vcl_send_session_shutdown (wrk, session);
+      session->flags |= VCL_SESSION_F_SHUTDOWN;
+    }
+
+  return VPPCOM_OK;
+}
+
 static int
 vppcom_session_disconnect (u32 session_handle)
 {
@@ -2101,7 +2154,8 @@ vppcom_session_write_inline (vcl_worker_t * wrk, vcl_session_t * s, void *buf,
       return VPPCOM_EBADFD;
     }
 
-  if (PREDICT_FALSE (!vcl_session_is_open (s)))
+  if (PREDICT_FALSE (!vcl_session_is_open (s) ||
+		     s->flags & VCL_SESSION_F_SHUTDOWN))
     {
       VDBG (1, "session %u [0x%llx]: is not open! state 0x%x (%s)",
 	    s->session_index, s->vpp_handle, s->session_state,
diff --git a/src/vcl/vppcom.h b/src/vcl/vppcom.h
index ae4888566c7..72e5d46bc8f 100644
--- a/src/vcl/vppcom.h
+++ b/src/vcl/vppcom.h
@@ -172,6 +172,7 @@ extern int vppcom_app_create (const char *app_name);
 extern void vppcom_app_destroy (void);
 
 extern int vppcom_session_create (uint8_t proto, uint8_t is_nonblocking);
+extern int vppcom_session_shutdown (uint32_t session_handle);
 extern int vppcom_session_close (uint32_t session_handle);
 extern int vppcom_session_bind (uint32_t session_handle, vppcom_endpt_t * ep);
 extern int vppcom_session_listen (uint32_t session_handle, uint32_t q_len);