DLT User: add ability to export PDUs

It can be really useful to share hand crafted captures without the need to configure the DLT User table

Change-Id: Iefab00b741f95b1f3a3247cb28ed01a367fa4ff4
Reviewed-on: https://code.wireshark.org/review/4469
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>
Tested-by: Pascal Quantin <pascal.quantin@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 25 insertions, 1 deletions

diff --git a/epan/dissectors/packet-user_encap.c b/epan/dissectors/packet-user_encap.c
index b220278841..45fc90488b 100644
--- a/epan/dissectors/packet-user_encap.c
+++ b/epan/dissectors/packet-user_encap.c
@@ -31,6 +31,8 @@
 #include <epan/prefs.h>
 #include <epan/uat.h>
 #include <epan/wmem/wmem.h>
+#include <epan/exported_pdu.h>
+#include <epan/tap.h>
 #include <wiretap/wtap.h>
 
 #ifdef _MSC_VER
@@ -82,11 +84,28 @@ static guint num_encaps = 0;
 static uat_t* encaps_uat;
 static dissector_handle_t data_handle;
 
+static gint exported_pdu_tap = -1;
+
 /*
  * Use this for DLT_USER2 if we don't have an encapsulation for it.
  */
 static user_encap_t user2_encap;
 
+static void export_pdu(tvbuff_t *tvb, packet_info* pinfo, char *proto_name)
+{
+    if (have_tap_listener(exported_pdu_tap)) {
+        exp_pdu_data_t *exp_pdu_data;
+        guint8 exp_pdu_data_tag;
+
+        exp_pdu_data_tag = EXP_PDU_TAG_ORIG_FNO_BIT;
+        exp_pdu_data = load_export_pdu_tags(pinfo, proto_name, -1, &exp_pdu_data_tag, 1);
+        exp_pdu_data->tvb_captured_length = tvb_captured_length(tvb);
+        exp_pdu_data->tvb_reported_length = tvb_reported_length(tvb);
+        exp_pdu_data->pdu_tvb = tvb;
+        tap_queue_packet(exported_pdu_tap, pinfo, exp_pdu_data);
+    }
+}
+
 static void dissect_user(tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree) {
     user_encap_t* encap = NULL;
     tvbuff_t* payload_tvb;
@@ -138,6 +157,7 @@ static void dissect_user(tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree) {
 
     if (encap->header_size) {
         tvbuff_t* hdr_tvb = tvb_new_subset_length(tvb, 0, encap->header_size);
+        export_pdu(hdr_tvb, pinfo, encap->header_proto_name);
         call_dissector(encap->header_proto, hdr_tvb, pinfo, tree);
         if (encap->header_proto_name) {
             const char *proto_name = dissector_handle_get_long_name(find_dissector(encap->header_proto_name));
@@ -147,10 +167,11 @@ static void dissect_user(tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree) {
         }
     }
 
-    len = tvb_length(tvb) - (encap->header_size + encap->trailer_size);
+    len = tvb_captured_length(tvb) - (encap->header_size + encap->trailer_size);
     reported_len = tvb_reported_length(tvb) - (encap->header_size + encap->trailer_size);
 
     payload_tvb = tvb_new_subset(tvb, encap->header_size, len, reported_len);
+    export_pdu(payload_tvb, pinfo, encap->payload_proto_name);
     call_dissector(encap->payload_proto, payload_tvb, pinfo, tree);
     if (encap->payload_proto_name) {
         const char *proto_name = dissector_handle_get_long_name(find_dissector(encap->payload_proto_name));
@@ -161,6 +182,7 @@ static void dissect_user(tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree) {
 
     if (encap->trailer_size) {
         tvbuff_t* trailer_tvb = tvb_new_subset_length(tvb, encap->header_size + len, encap->trailer_size);
+        export_pdu(trailer_tvb, pinfo, encap->trailer_proto_name);
         call_dissector(encap->trailer_proto, trailer_tvb, pinfo, tree);
         if (encap->trailer_proto_name) {
             const char *proto_name = dissector_handle_get_long_name(find_dissector(encap->trailer_proto_name));
@@ -282,6 +304,8 @@ void proto_register_user_encap(void)
     prefs_register_protocol_obsolete(proto_register_protocol("DLT User C","DLT_USER_C","user_dlt_c"));
     prefs_register_protocol_obsolete(proto_register_protocol("DLT User D","DLT_USER_D","user_dlt_d"));
     */
+
+    exported_pdu_tap = register_export_pdu_tap("DLT User");
 }
 
 /*