3 files changed, 17 insertions, 8 deletions

diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index e634a06b532..138953b4ed4 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -643,14 +643,18 @@ app_send_io_evt_to_vpp (svm_msg_q_t * mq, u32 session_index, u8 evt_type,
     }
 }
 
+#define app_send_dgram_raw(f, at, vpp_evt_q, data, len, evt_type, do_evt,     \
+			   noblock)                                           \
+  app_send_dgram_raw_gso (f, at, vpp_evt_q, data, len, 0, evt_type, do_evt,   \
+			  noblock)
+
 always_inline int
-app_send_dgram_raw (svm_fifo_t * f, app_session_transport_t * at,
-		    svm_msg_q_t * vpp_evt_q, u8 * data, u32 len, u8 evt_type,
-		    u8 do_evt, u8 noblock)
+app_send_dgram_raw_gso (svm_fifo_t *f, app_session_transport_t *at,
+			svm_msg_q_t *vpp_evt_q, u8 *data, u32 len,
+			u16 gso_size, u8 evt_type, u8 do_evt, u8 noblock)
 {
   session_dgram_hdr_t hdr;
   int rv;
-
   if (svm_fifo_max_enqueue_prod (f) < (sizeof (session_dgram_hdr_t) + len))
     return 0;
 
@@ -661,7 +665,7 @@ app_send_dgram_raw (svm_fifo_t * f, app_session_transport_t * at,
   hdr.rmt_port = at->rmt_port;
   clib_memcpy_fast (&hdr.lcl_ip, &at->lcl_ip, sizeof (ip46_address_t));
   hdr.lcl_port = at->lcl_port;
-
+  hdr.gso_size = gso_size;
   /* *INDENT-OFF* */
   svm_fifo_seg_t segs[2] = {{ (u8 *) &hdr, sizeof (hdr) }, { data, len }};
   /* *INDENT-ON* */
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index be00925bb00..150da259da6 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -1222,6 +1222,11 @@ session_tx_set_dequeue_params (vlib_main_t * vm, session_tx_context_t * ctx,
 	  ASSERT (ctx->hdr.data_length > ctx->hdr.data_offset);
 	  len = ctx->hdr.data_length - ctx->hdr.data_offset;
 
+	  if (ctx->hdr.gso_size)
+	    {
+	      ctx->sp.snd_mss = clib_min (ctx->sp.snd_mss, ctx->hdr.gso_size);
+	    }
+
 	  /* Process multiple dgrams if smaller than min (buf_space, mss).
 	   * This avoids handling multiple dgrams if they require buffer
 	   * chains */
diff --git a/src/vnet/session/session_types.h b/src/vnet/session/session_types.h
index 95a88c5ab6e..dcbbd72ef8e 100644
--- a/src/vnet/session/session_types.h
+++ b/src/vnet/session/session_types.h
@@ -461,12 +461,12 @@ typedef struct session_dgram_header_
   u16 rmt_port;
   u16 lcl_port;
   u8 is_ip4;
+  u16 gso_size;
 } __clib_packed session_dgram_hdr_t;
 
 #define SESSION_CONN_ID_LEN 37
-#define SESSION_CONN_HDR_LEN 45
-
-STATIC_ASSERT (sizeof (session_dgram_hdr_t) == (SESSION_CONN_ID_LEN + 8),
+#define SESSION_CONN_HDR_LEN 47
+STATIC_ASSERT (sizeof (session_dgram_hdr_t) == (SESSION_CONN_ID_LEN + 10),
 	       "session conn id wrong length");
 
 #define foreach_session_error                                                 \