dissect some more E-LMI fields

Change-Id: I9b0cb7c8602f813fd06f1b3ea6107ed6fe8d72ed
Reviewed-on: https://code.wireshark.org/review/1244
Reviewed-by: Martin Kaiser <wireshark@kaiser.cx>
Tested-by: Martin Kaiser <wireshark@kaiser.cx>

1 files changed, 118 insertions, 2 deletions

diff --git a/epan/dissectors/packet-elmi.c b/epan/dissectors/packet-elmi.c
index 70074721ae..c2dc077873 100644
--- a/epan/dissectors/packet-elmi.c
+++ b/epan/dissectors/packet-elmi.c
@@ -41,9 +41,16 @@ void proto_register_elmi(void);
 void proto_reg_handoff_elmi(void);
 
 static gint ett_elmi = -1;
+static gint ett_elmi_info_elem = -1;
 
 static int hf_elmi_ver = -1;
 static int hf_elmi_msg_type = -1;
+static int hf_elmi_info_elem = -1;
+static int hf_elmi_info_elem_len = -1;
+static int hf_elmi_report_type = -1;
+static int hf_elmi_snd_seq_num = -1;
+static int hf_elmi_rcv_seq_num = -1;
+static int hf_elmi_dat_inst = -1;
 
 static const value_string elmi_msg_type[] = {
     { 0x75, "Status enquiry" },
@@ -51,6 +58,85 @@ static const value_string elmi_msg_type[] = {
     { 0, NULL }
 };
 
+#define TAG_REPORT_TYPE 0x01
+#define TAG_SEQ_NUM     0x02
+#define TAG_DATA_INST   0x03
+
+static const value_string elmi_info_elem_tag[] = {
+    { TAG_REPORT_TYPE, "Report type" },
+    { TAG_SEQ_NUM,     "Sequence numbers" },
+    { TAG_DATA_INST,   "Data instance" },
+    { 0, NULL }
+};
+
+static const value_string elmi_report_type[] = {
+    { 0x00, "Full status" },
+    { 0x01, "E-LMI check" },
+    { 0x02, "Single EVC async status" },
+    { 0x03, "Full status continued" },
+    { 0, NULL }
+};
+
+
+static gint
+dissect_elmi_info_elem(
+        tvbuff_t *tvb, gint offset, packet_info *pinfo _U_, proto_tree *tree)
+{
+    gint        offset_start;
+    guint8      tag, len;
+    proto_item *tree_pi;
+    proto_tree *info_elem_tree;
+
+    offset_start = offset;
+
+    tag = tvb_get_guint8(tvb, offset);
+    if (tag==0)
+        return -1;
+
+    tree_pi = proto_tree_add_text(
+            tree, tvb, offset, -1, "Information element: %s",
+            val_to_str_const(tag, elmi_info_elem_tag, "unknown"));
+    info_elem_tree = proto_item_add_subtree(tree_pi, ett_elmi_info_elem);
+
+    proto_tree_add_item(info_elem_tree, hf_elmi_info_elem,
+            tvb, offset, 1, ENC_BIG_ENDIAN);
+    offset++;
+
+    len = tvb_get_guint8(tvb, offset);
+    proto_tree_add_item(info_elem_tree, hf_elmi_info_elem_len,
+            tvb, offset, 1, ENC_BIG_ENDIAN);
+    offset++;
+
+    switch (tag) {
+        case TAG_REPORT_TYPE:
+            proto_tree_add_item(info_elem_tree, hf_elmi_report_type,
+                    tvb, offset, 1, ENC_BIG_ENDIAN);
+            offset++;
+            break;
+        case TAG_SEQ_NUM:
+            proto_tree_add_item(info_elem_tree, hf_elmi_snd_seq_num,
+                    tvb, offset, 1, ENC_BIG_ENDIAN);
+            offset++;
+            proto_tree_add_item(info_elem_tree, hf_elmi_rcv_seq_num,
+                    tvb, offset, 1, ENC_BIG_ENDIAN);
+            offset++;
+            break;
+        case TAG_DATA_INST:
+            proto_tree_add_text(info_elem_tree, tvb, offset, 1, "Reserved");
+            offset++;
+            proto_tree_add_item(info_elem_tree, hf_elmi_dat_inst,
+                    tvb, offset, 4, ENC_BIG_ENDIAN);
+            offset+=4;
+            break;
+        default:
+            offset += len;
+            break;
+    }
+
+    proto_item_set_len(tree_pi, offset-offset_start);
+    return offset-offset_start;
+}
+
 
 static int
 dissect_elmi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
@@ -59,6 +145,7 @@ dissect_elmi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_
     proto_tree *elmi_tree;
     gint        offset=0;
     guint8      msg_type;
+    gint        ret;
 
     col_clear(pinfo->cinfo, COL_INFO);
     col_set_str(pinfo->cinfo, COL_PROTOCOL, "E-LMI");
@@ -76,7 +163,17 @@ dissect_elmi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_
             tvb, offset, 1, ENC_BIG_ENDIAN);
     col_append_fstr(pinfo->cinfo, COL_INFO, "%s",
             val_to_str(msg_type, elmi_msg_type, "unknown (0x%x)"));
+    offset++;
+
+    while (tvb_reported_length_remaining(tvb, offset) > 0) {
+        ret = dissect_elmi_info_elem(tvb, offset, pinfo, elmi_tree);
+        if (ret<=0)
+            break;
+        offset += ret;
+    }
 
+    /* XXX - can we make the eth dissector handle our (standard) padding
+     * and FCS? */
     return tvb_captured_length(tvb);
 }
 
@@ -90,11 +187,30 @@ proto_register_elmi(void)
                 NULL, 0, NULL, HFILL } },
         { &hf_elmi_msg_type,
             { "Message type", "elmi.message_type", FT_UINT8, BASE_HEX,
-                VALS(elmi_msg_type), 0, NULL, HFILL } }
+                VALS(elmi_msg_type), 0, NULL, HFILL } },
+        { &hf_elmi_info_elem,
+            { "Tag", "elmi.info_element.tag", FT_UINT8, BASE_HEX,
+                VALS(elmi_info_elem_tag), 0, NULL, HFILL } },
+        { &hf_elmi_info_elem_len,
+            { "Length", "elmi.info_element.length", FT_UINT8, BASE_DEC,
+                NULL, 0, NULL, HFILL } },
+        { &hf_elmi_report_type,
+            { "Report type", "elmi.report_type", FT_UINT8, BASE_DEC,
+                VALS(elmi_report_type), 0, NULL, HFILL } },
+        { &hf_elmi_snd_seq_num,
+            { "Send sequence number", "elmi.snd_seq_num", FT_UINT8, BASE_DEC,
+                NULL, 0, NULL, HFILL } },
+        { &hf_elmi_rcv_seq_num,
+            { "Receive sequence number", "elmi.rcv_seq_num", FT_UINT8, BASE_DEC,
+                NULL, 0, NULL, HFILL } },
+        { &hf_elmi_dat_inst,
+            { "Data instance", "elmi.data_instance", FT_UINT32, BASE_HEX,
+                NULL, 0, NULL, HFILL } }
     };
 
     static gint *ett[] = {
-        &ett_elmi
+        &ett_elmi,
+        &ett_elmi_info_elem
     };