Reassembly: add additional_bytes_expected_to_complete_reassembly function

Get how many additional bytes are expected to complete current streaming
reassembly. Used to check if the current streaming reassembly is complete.

epan/reassemble.c

@@ -3533,6 +3533,12 @@ reassemble_streaming_data_and_call_subdissector(
 	return orig_length;
 }
 
+gint
+additional_bytes_expected_to_complete_reassembly(streaming_reassembly_info_t* reassembly_info)
+{
+	return reassembly_info->prev_deseg_len;
+}
+
 /*
  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
  *

epan/reassemble.h

@@ -1119,6 +1119,16 @@ get_virtual_frame_num64(tvbuff_t* tvb, packet_info* pinfo, gint offset)
 		+ ((guint64)tvb_raw_offset(tvb) + offset);
 }
 
+/**
+ * How many additional bytes are still expected to complete this reassembly?
+ *
+ * @return How many additional bytes are expected to complete this reassembly.
+ *         It may also be DESEGMENT_ONE_MORE_SEGMENT.
+ *         0 means this reassembly is completed.
+ */
+WS_DLL_PUBLIC gint
+additional_bytes_expected_to_complete_reassembly(streaming_reassembly_info_t* reassembly_info);
+
 /* ========================================================================= */
 
 #endif

packaging/debian/libwireshark0.symbols

@@ -33,6 +33,7 @@ libwireshark.so.0 libwireshark0 #MINVER#
  add_new_data_source@Base 1.9.1
  add_per_encoded_label@Base 3.7.0
  add_srt_table_data@Base 1.99.8
+ additional_bytes_expected_to_complete_reassembly@Base 4.1.0
  address_to_bytes@Base 2.1.1
  address_to_display@Base 1.99.2
  address_to_name@Base 2.1.0