Add support for BASE_VALS_NO_UNKNOWN

BASE_VALS_NO_UNKNOWN is a special value_string value for only a single
(maybe 2) numerical value(s).  If a field has the numerical value
that doesn't match anything in the value_string, just the number
is supplied for the field (no "Unknown")

Dissectors that had this use case have been converted in the patch.

Change-Id: Ie63a36cceec2fe4436938ec7e3d7f9e690d2b8d9
Reviewed-on: https://code.wireshark.org/review/20736
Petri-Dish: Michael Mann <mmann78@netscape.net>
Reviewed-by: Michael Mann <mmann78@netscape.net>

2 files changed, 15 insertions, 14 deletions

diff --git a/plugins/docsis/packet-docsis.c b/plugins/docsis/packet-docsis.c
index bc17b6eeb5..39a592b6d8 100644
--- a/plugins/docsis/packet-docsis.c
+++ b/plugins/docsis/packet-docsis.c
@@ -254,6 +254,11 @@ static const true_false_string odd_even_tfs = {
   "Even Key",
 };
 
+static const value_string unique_no_phs[] = {
+  { 0, "No PHS on current packet" },
+  { 0, NULL }
+};
+
 /* Fragmentation Flags / Sequence */
 static guint8 frag_flags;
 static guint8 frag_seq;
@@ -288,13 +293,11 @@ static void
 dissect_ehdr (tvbuff_t * tvb, proto_tree * tree, packet_info * pinfo)
 {
   proto_tree *ehdr_tree;
-  proto_item *item_pshi;
   proto_item *eh_length_item;
   gint ehdrlen;
   int pos;
   guint8 type;
   guint8 len;
-  guint8 val;
 
   ehdrlen = tvb_get_guint8 (tvb, 1);
   pos = 4;
@@ -392,12 +395,7 @@ dissect_ehdr (tvbuff_t * tvb, proto_tree * tree, packet_info * pinfo)
         /* Deprecated in DOCSIS 3.1, was Downstream Service Flow EH Element in earlier revisions */
       case EH_SFLOW_HDR_UP:
         /* Deprecated in DOCSIS 3.1, was Upstream Service Flow EH Element in earlier revisions */
-        val = tvb_get_guint8 (tvb, pos+1);
-        item_pshi = proto_tree_add_item(ehdr_tree, hf_docsis_ehdr_phsi, tvb, pos+1, 1, ENC_BIG_ENDIAN);
-        if (val == 0)
-        {
-          proto_item_append_text(item_pshi, " (No PHS on current packet)" );
-        }
+        proto_tree_add_item(ehdr_tree, hf_docsis_ehdr_phsi, tvb, pos+1, 1, ENC_BIG_ENDIAN);
 
         if (len == 2)
         {
@@ -952,7 +950,7 @@ proto_register_docsis (void)
     },
     {&hf_docsis_ehdr_phsi,
      {"Payload Header Suppression Index", "docsis.ehdr.phsi",
-      FT_UINT8, BASE_DEC, NULL, 0x0,
+      FT_UINT8, BASE_DEC|BASE_VALS_NO_UNKNOWN, VALS(unique_no_phs), 0x0,
       NULL, HFILL}
     },
     {&hf_docsis_ehdr_qind,
diff --git a/plugins/docsis/packet-mdd.c b/plugins/docsis/packet-mdd.c
index 614da44357..71d99568d0 100644
--- a/plugins/docsis/packet-mdd.c
+++ b/plugins/docsis/packet-mdd.c
@@ -284,6 +284,12 @@ static const value_string upstream_transmit_power_reporting_vals[] = {
   {0, NULL}
 };
 
+static const value_string unique_unlimited[] = {
+  { 0, "Unlimited" },
+  {0, NULL}
+};
+
+
 /* Windows does not allow data copy between dlls */
 const true_false_string mdd_tfs_on_off = { "On", "Off" };
 
@@ -546,10 +552,7 @@ dissect_mdd (tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree, void* data
                     proto_item_append_text(text_item, " (%d ms)", (256*tvb_get_guint8 (tvb, subpos) + tvb_get_guint8 (tvb, subpos + 1)) * 20);
                     break;
                   case MAXIMUM_NUMBER_OF_REPORTS_PER_EVENT:
-                    text_item = proto_tree_add_item (tlv_tree, hf_docsis_mdd_maximum_number_of_reports_per_event, tvb, subpos, 1, ENC_BIG_ENDIAN);
-                    if ( tvb_get_guint8 (tvb, subpos) == 0) {
-                      proto_item_append_text(text_item, " (Unlimited)");
-                    }
+                    proto_tree_add_item (tlv_tree, hf_docsis_mdd_maximum_number_of_reports_per_event, tvb, subpos, 1, ENC_BIG_ENDIAN);
                     break;
                 }
                 subpos += sublength + 2;
@@ -770,7 +773,7 @@ void proto_register_docsis_mdd (void)
     },
     {&hf_docsis_mdd_maximum_number_of_reports_per_event,
      {"Maximum Number of Reports per Event", "docsis_mdd.maximum_number_of_reports_per_event",
-      FT_UINT8, BASE_DEC, NULL, 0x0,
+      FT_UINT8, BASE_DEC|BASE_VALS_NO_UNKNOWN, VALS(unique_unlimited), 0x0,
       "Mdd Maximum Number of Reports per Event", HFILL}
     },
     {&hf_docsis_mdd_upstream_transmit_power_reporting,