Add code and a preference to use GSM SAPI to call sub dissectors.

https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=9017

svn path=/trunk/; revision=51171

1 files changed, 37 insertions, 3 deletions

diff --git a/epan/dissectors/packet-iua.c b/epan/dissectors/packet-iua.c
index 9fa59dc8d6..23cc2846c2 100644
--- a/epan/dissectors/packet-iua.c
+++ b/epan/dissectors/packet-iua.c
@@ -36,9 +36,16 @@
 #include <epan/packet.h>
 #include <epan/prefs.h>
 #include <epan/sctpppids.h>
+#include <epan/lapd_sapi.h>
 
 static module_t *iua_module;
 
+static dissector_handle_t data_handle;
+static dissector_table_t lapd_gsm_sapi_dissector_table;
+
+/* Whether to use GSM SAPI vals or not */
+static gboolean global_iua_gsm_sapis = TRUE;
+
 /* Initialize the protocol and registered fields */
 static int proto_iua                = -1;
 static int hf_int_interface_id      = -1;
@@ -47,6 +54,7 @@ static int hf_info_string           = -1;
 static int hf_dlci_zero_bit         = -1;
 static int hf_dlci_spare_bit        = -1;
 static int hf_dlci_sapi             = -1;
+static int hf_dlci_gsm_sapi         = -1;
 static int hf_dlci_one_bit          = -1;
 static int hf_dlci_tei              = -1;
 static int hf_dlci_spare            = -1;
@@ -176,6 +184,14 @@ static const value_string sapi_values[] = {
   { 0,                        NULL }
 };
 
+static const value_string gsm_sapi_vals[] = {
+	{ LAPD_GSM_SAPI_RA_SIG_PROC,	"Radio signalling procedures" },
+	{ LAPD_GSM_SAPI_NOT_USED_1,	"(Not used in GSM PLMN)" },
+	{ LAPD_GSM_SAPI_NOT_USED_16,	"(Not used in GSM PLMN)" },
+	{ LAPD_GSM_SAPI_OM_PROC,	"Operation and maintenance procedure" },
+	{ LAPD_SAPI_L2,			"Layer 2 management procedures" },
+	{ 0,				NULL }
+};
 
 static void
 dissect_dlci_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree)
@@ -185,9 +201,12 @@ dissect_dlci_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree)
   proto_tree_add_item(parameter_tree, hf_dlci_spare_bit, parameter_tvb, DLCI_SAPI_OFFSET,  DLCI_SAPI_LENGTH,  ENC_BIG_ENDIAN);
   /* Add the SAPI + some explanatory text, store the SAPI value so that we can later how to
    * dissect the protocol data */
-  sapi_item = proto_tree_add_item(parameter_tree, hf_dlci_sapi, parameter_tvb, DLCI_SAPI_OFFSET,  DLCI_SAPI_LENGTH,  ENC_BIG_ENDIAN);
+  if(global_iua_gsm_sapis){
+    sapi_item = proto_tree_add_item(parameter_tree, hf_dlci_gsm_sapi, parameter_tvb, DLCI_SAPI_OFFSET,  DLCI_SAPI_LENGTH,  ENC_BIG_ENDIAN);
+  }else{
+    sapi_item = proto_tree_add_item(parameter_tree, hf_dlci_sapi, parameter_tvb, DLCI_SAPI_OFFSET,  DLCI_SAPI_LENGTH,  ENC_BIG_ENDIAN);
+  }
   sapi_val = (tvb_get_guint8(parameter_tvb, DLCI_SAPI_OFFSET) & SAPI_MASK) >> SAPI_SHIFT;
-  proto_item_append_text(sapi_item, " (%s)", val_to_str_const( sapi_val, sapi_values, "Unknown/reserved"));
   sapi_val_assigned = TRUE;
 
   proto_tree_add_item(parameter_tree, hf_dlci_one_bit,   parameter_tvb, DLCI_TEI_OFFSET,   DLCI_TEI_LENGTH,   ENC_BIG_ENDIAN);
@@ -409,6 +428,11 @@ dissect_protocol_data_parameter(tvbuff_t *parameter_tvb, proto_item *parameter_i
   {
     return;
   }
+  if(global_iua_gsm_sapis){
+    if (!dissector_try_uint(lapd_gsm_sapi_dissector_table, sapi_val, protocol_data_tvb, pinfo, tree))
+				call_dissector(data_handle, protocol_data_tvb, pinfo, tree);
+    return;
+  }
 
   switch(sapi_val)
   {
@@ -906,7 +930,8 @@ proto_register_iua(void)
     { &hf_info_string,           { "Info string",                  "iua.info_string",               FT_STRING,  BASE_NONE, NULL,                           0x0,            NULL, HFILL } },
     { &hf_dlci_zero_bit,         { "Zero bit",                     "iua.dlci_zero_bit",             FT_BOOLEAN, 8,         NULL,                           ZERO_BIT_MASK,  NULL, HFILL } },
     { &hf_dlci_spare_bit,        { "Spare bit",                    "iua.dlci_spare_bit",            FT_BOOLEAN, 8,         NULL,                           SPARE_BIT_MASK, NULL, HFILL } },
-    { &hf_dlci_sapi,             { "SAPI",                         "iua.dlci_sapi",                 FT_UINT8,   BASE_HEX,  NULL,                           SAPI_MASK,      NULL, HFILL } },
+    { &hf_dlci_sapi,             { "SAPI",                         "iua.dlci_sapi",                 FT_UINT8,   BASE_HEX,  VALS(sapi_values),              SAPI_MASK,      NULL, HFILL } },
+    { &hf_dlci_gsm_sapi,             { "SAPI",                     "iua.dlci_gsm_sapi",             FT_UINT8,   BASE_HEX,  VALS(gsm_sapi_vals),            SAPI_MASK,      NULL, HFILL } },
     { &hf_dlci_one_bit,          { "One bit",                      "iua.dlci_one_bit",              FT_BOOLEAN, 8,         NULL,                           ONE_BIT_MASK,   NULL, HFILL } },
     { &hf_dlci_tei,              { "TEI",                          "iua.dlci_tei",                  FT_UINT8,   BASE_HEX,  NULL,                           TEI_MASK,       NULL, HFILL } },
     { &hf_dlci_spare,            { "Spare",                        "iua.dlci_spare",                FT_UINT16,  BASE_HEX,  NULL,                           0x0,            NULL, HFILL } },
@@ -949,6 +974,11 @@ proto_register_iua(void)
   proto_register_subtree_array(ett, array_length(ett));
   prefs_register_bool_preference(iua_module, "support_ig", "Support Implementers Guide", "Support Implementers Guide (version 01)", &support_IG);
 
+  prefs_register_bool_preference(iua_module, "use_gsm_sapi_values",
+        "Use GSM SAPI values",
+        "Use SAPI values as specified in TS 48 056",
+        &global_iua_gsm_sapis);
+
   /* Allow other dissectors to find this one by name. */
   register_dissector("iua", dissect_iua, proto_iua);
 }
@@ -966,4 +996,8 @@ proto_reg_handoff_iua(void)
 
   dissector_add_uint("sctp.port", SCTP_PORT_IUA,           iua_handle);
   dissector_add_uint("sctp.ppi",  IUA_PAYLOAD_PROTOCOL_ID, iua_handle);
+
+  lapd_gsm_sapi_dissector_table = find_dissector_table("lapd.gsm.sapi");
+  data_handle = find_dissector("data");
+
 }