dissect_uleb128 -> tvb_get_varint/proto_tree_add_item_ret_length

Also update ENC_VARINT_PROTOBUF documentation while we're at it

Change-Id: I72e1f9175adc0c6a8bb03ceddba04ffd4844a12e
Reviewed-on: https://code.wireshark.org/review/24485
Reviewed-by: Michael Mann <mmann78@netscape.net>

6 files changed, 30 insertions, 68 deletions

diff --git a/epan/dissectors/file-elf.c b/epan/dissectors/file-elf.c
index c85f1e360f..3452524b86 100644
--- a/epan/dissectors/file-elf.c
+++ b/epan/dissectors/file-elf.c
@@ -887,7 +887,7 @@ dissect_eh_frame_hdr(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *segment_
     if (efp_length == LENGTH_ULEB128) {
         guint64 value;
 
-        efp_length = dissect_uleb128(tvb, offset, &value);
+        efp_length = tvb_get_varint(tvb, offset, FT_VARINT_MAX_LEN, &value);
     } else if (efp_length == LENGTH_LEB128) {
         gint64 value;
 
@@ -899,7 +899,7 @@ dissect_eh_frame_hdr(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *segment_
 
 
     if (fde_count_length == LENGTH_ULEB128) {
-        fde_count_length = dissect_uleb128(tvb, offset, &fde_count);
+        fde_count_length = tvb_get_varint(tvb, offset, FT_VARINT_MAX_LEN, &fde_count);
     } else if (fde_count_length == LENGTH_LEB128) {
         gint64 value;
 
@@ -932,7 +932,7 @@ dissect_eh_frame_hdr(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *segment_
     if (table_entry_length == LENGTH_ULEB128) {
         guint64 value;
 
-        table_entry_length = dissect_uleb128(tvb, offset, &value);
+        table_entry_length = tvb_get_varint(tvb, offset, FT_VARINT_MAX_LEN, &value);
     } else if (table_entry_length == LENGTH_LEB128) {
         gint64 value;
 
@@ -1064,9 +1064,7 @@ dissect_eh_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *segment_tree,
                                 tvb, offset, size, machine_encoding);
             offset += size;
 
-            size = dissect_uleb128(tvb, offset, &unsigned_value);
-            proto_tree_add_uint64(entry_tree, hf_elf_eh_frame_code_alignment_factor,
-                                  tvb, offset, size, unsigned_value);
+            proto_tree_add_item_ret_length(entry_tree, hf_elf_eh_frame_code_alignment_factor, tvb, offset, -1, ENC_LITTLE_ENDIAN|ENC_VARINT_PROTOBUF, &size);
             offset += size;
 
             size = dissect_leb128(tvb, offset, &signed_value);
@@ -1075,9 +1073,7 @@ dissect_eh_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *segment_tree,
             offset += size;
 
             /* according to DWARF v4 this is uLEB128 */
-            size = dissect_uleb128(tvb, offset, &unsigned_value);
-            proto_tree_add_uint64(entry_tree, hf_elf_eh_frame_return_address_register,
-                                  tvb, offset, size, unsigned_value);
+            proto_tree_add_item_ret_length(entry_tree, hf_elf_eh_frame_return_address_register, tvb, offset, -1, ENC_LITTLE_ENDIAN|ENC_VARINT_PROTOBUF, &size);
             offset += size;
         } else {
             proto_tree_add_item(entry_tree, hf_elf_eh_frame_fde_pc_begin, tvb,
@@ -1092,11 +1088,8 @@ dissect_eh_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *segment_tree,
         /* "A 'z' may be present as the first character of the string. If
          * present, the Augmentation Data field shall be present." (LSB 4.1) */
         if (augmentation_string[0] == 'z') {
-            size = dissect_uleb128(tvb, offset, &unsigned_value);
-            proto_tree_add_uint64(entry_tree, is_cie ?
-                                    hf_elf_eh_frame_augmentation_length :
-                                    hf_elf_eh_frame_fde_augmentation_length,
-                                  tvb, offset, size, unsigned_value);
+            proto_tree_add_item_ret_varint(entry_tree, is_cie ? hf_elf_eh_frame_augmentation_length : hf_elf_eh_frame_fde_augmentation_length,
+                                            tvb, offset, -1, ENC_LITTLE_ENDIAN|ENC_VARINT_PROTOBUF, &unsigned_value, &size);
             offset += size;
 
             proto_tree_add_item(entry_tree, is_cie ?
diff --git a/epan/dissectors/packet-mqtt.c b/epan/dissectors/packet-mqtt.c
index fee3bf962e..c7a9a98683 100644
--- a/epan/dissectors/packet-mqtt.c
+++ b/epan/dissectors/packet-mqtt.c
@@ -368,18 +368,16 @@ static gint ett_mqtt_subscription_flags = -1;
 /* Reassemble SMPP TCP segments */
 static gboolean reassemble_mqtt_over_tcp = TRUE;
 
-#define GET_MQTT_PDU_LEN(msg_len, len_offset)    (msg_len + len_offset + MQTT_HDR_SIZE_BEFORE_LEN)
-
 static guint get_mqtt_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb,
                               int offset, void *data _U_)
 {
   guint64 msg_len;
   guint len_offset;
 
-  len_offset = dissect_uleb128(tvb, (offset + MQTT_HDR_SIZE_BEFORE_LEN), &msg_len);
+  len_offset = tvb_get_varint(tvb, (offset + MQTT_HDR_SIZE_BEFORE_LEN), FT_VARINT_MAX_LEN, &msg_len);
 
   /* Explicitly downcast the value, because the length can never be more than 4 bytes */
-  return (guint)(GET_MQTT_PDU_LEN(msg_len, len_offset));
+  return (guint)(msg_len + len_offset + MQTT_HDR_SIZE_BEFORE_LEN);
 }
 
 static void *mqtt_message_decode_copy_cb(void *dest, const void *orig, size_t len _U_)
@@ -509,7 +507,7 @@ static guint dissect_mqtt_properties(tvbuff_t *tvb, proto_tree *mqtt_tree, guint
   proto_item *ti;
   guint64 vbi;
 
-  const guint mqtt_prop_offset = dissect_uleb128(tvb, offset, &vbi);
+  const guint mqtt_prop_offset = tvb_get_varint(tvb, offset, FT_VARINT_MAX_LEN, &vbi);
   /* Property Length field can be stored in uint32 */
   const guint mqtt_prop_len = (gint)vbi;
 
@@ -563,9 +561,9 @@ static guint dissect_mqtt_properties(tvbuff_t *tvb, proto_tree *mqtt_tree, guint
 
       case PROP_SUBSCRIPTION_IDENTIFIER:
       {
-        guint8 vbi_offset = dissect_uleb128(tvb, offset, &vbi);
-        proto_tree_add_uint(mqtt_prop_tree, hf_mqtt_prop_num, tvb, offset, vbi_offset, (guint32)vbi);
-        offset += vbi_offset;
+        gint vbi_len;
+        proto_tree_add_item_ret_length(mqtt_prop_tree, hf_mqtt_prop_num, tvb, offset, -1, ENC_LITTLE_ENDIAN|ENC_VARINT_PROTOBUF, &vbi_len);
+        offset += vbi_len;
         break;
       }
 
@@ -681,7 +679,7 @@ static int dissect_mqtt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, voi
     conversation_add_proto_data(conv, proto_mqtt, mqtt);
   }
 
-  mqtt_len_offset = dissect_uleb128(tvb, (offset + MQTT_HDR_SIZE_BEFORE_LEN), &msg_len);
+  mqtt_len_offset = tvb_get_varint(tvb, (offset + MQTT_HDR_SIZE_BEFORE_LEN), FT_VARINT_MAX_LEN, &msg_len);
 
   /* Explicit downcast, typically maximum length of message could be 4 bytes */
   mqtt_msg_len = (gint) msg_len;
diff --git a/epan/dissectors/packet-netsync.c b/epan/dissectors/packet-netsync.c
index 33dc93256f..39374424d8 100644
--- a/epan/dissectors/packet-netsync.c
+++ b/epan/dissectors/packet-netsync.c
@@ -158,7 +158,7 @@ static gint dissect_netsync_cmd_error( tvbuff_t *tvb,  gint offset, proto_tree *
 {
 	guint64 len = 0;
 
-	offset += dissect_uleb128( tvb, offset, &len );
+	offset += tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &len );
 
 	proto_tree_add_item(tree, hf_netsync_cmd_error_msg, tvb,
 				offset, (gint)len, ENC_ASCII|ENC_NA );
@@ -177,15 +177,13 @@ static gint dissect_netsync_cmd_hello(tvbuff_t *tvb,  gint offset, proto_tree *t
 {
 	guint64 len = 0;
 
-	offset += dissect_uleb128( tvb, offset, &len );
-
+	offset += tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &len );
 	proto_tree_add_item(tree, hf_netsync_cmd_hello_keyname, tvb,
 				offset, (gint)len, ENC_ASCII|ENC_NA );
 	offset += (gint)len;
 
 
-	offset += dissect_uleb128( tvb, offset, &len );
-
+	offset += tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &len );
 	proto_tree_add_item(tree, hf_netsync_cmd_hello_key, tvb,
 				offset, (gint)len, ENC_NA );
 	offset += (gint)len;
@@ -206,8 +204,7 @@ static gint dissect_netsync_cmd_anonymous(tvbuff_t *tvb,  gint offset, proto_tre
 				offset, 1, ENC_BIG_ENDIAN );
 	offset += 1;
 
-	offset += dissect_uleb128( tvb, offset, &len );
-
+	offset += tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &len );
 	proto_tree_add_item(tree, hf_netsync_cmd_anonymous_collection, tvb,
 				offset, (gint)len, ENC_ASCII|ENC_NA );
 	offset += (gint)len;
@@ -229,8 +226,7 @@ static gint dissect_netsync_cmd_auth(tvbuff_t *tvb,  gint offset, proto_tree *tr
 	offset += 1;
 
 
-	offset += dissect_uleb128( tvb, offset, &len );
-
+	offset += tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &len );
 	proto_tree_add_item(tree, hf_netsync_cmd_auth_collection, tvb,
 				offset, (gint)len, ENC_ASCII|ENC_NA );
 	offset += (gint)len;
@@ -251,8 +247,7 @@ static gint dissect_netsync_cmd_auth(tvbuff_t *tvb,  gint offset, proto_tree *tr
 				offset, NETSNYC_MERKLE_HASH_LENGTH, ENC_NA );
 	offset += NETSNYC_MERKLE_HASH_LENGTH;
 
-	offset += dissect_uleb128( tvb, offset, &len );
-
+	offset += tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &len );
 	proto_tree_add_item(tree, hf_netsync_cmd_auth_sig, tvb,
 				offset, (gint)len, ENC_NA );
 	offset += (gint)len;
@@ -265,8 +260,7 @@ static gint dissect_netsync_cmd_confirm(tvbuff_t *tvb,  gint offset, proto_tree
 {
 	guint64 len = 0;
 
-	offset += dissect_uleb128( tvb, offset, &len );
-
+	offset += tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &len );
 	proto_tree_add_item(tree, hf_netsync_cmd_confirm_sig, tvb,
 				offset, (gint)len, ENC_NA );
 	offset += (gint)len;
@@ -288,13 +282,10 @@ static gint dissect_netsync_cmd_refine(tvbuff_t *tvb,  gint offset, proto_tree *
 
 static gint dissect_netsync_cmd_done(tvbuff_t *tvb,  gint offset, proto_tree *tree, guint size _U_)
 {
-	guint64 len = 0;
-	guint bytes = 0;
-
-	bytes = dissect_uleb128( tvb, offset, &len );
+	gint bytes = 0;
 
-	proto_tree_add_uint(tree, hf_netsync_cmd_done_level, tvb,
-					offset, bytes, (guint32)len );
+	proto_tree_add_item_ret_length(tree, hf_netsync_cmd_done_level, tvb,
+					offset, -1, ENC_LITTLE_ENDIAN|ENC_VARINT_PROTOBUF, &bytes);
 	offset += bytes;
 
 	proto_tree_add_item(tree, hf_netsync_cmd_done_type, tvb,
@@ -354,8 +345,7 @@ static gint dissect_netsync_cmd_data(tvbuff_t *tvb,  gint offset, proto_tree *tr
 				offset, 1, ENC_BIG_ENDIAN );
 	offset += 1;
 
-	offset += dissect_uleb128( tvb, offset, &len );
-
+	offset += tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &len );
 	proto_tree_add_item(tree, hf_netsync_cmd_data_payload, tvb,
 				offset, (gint)len, ENC_NA );
 	offset += (gint)len;
@@ -384,8 +374,7 @@ static gint dissect_netsync_cmd_delta(tvbuff_t *tvb,  gint offset, proto_tree *t
 				offset, 1, ENC_BIG_ENDIAN );
 	offset += 1;
 
-	offset += dissect_uleb128( tvb, offset, &len );
-
+	offset += tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &len );
 	proto_tree_add_item(tree, hf_netsync_cmd_delta_payload, tvb,
 				offset, (gint)len, ENC_NA );
 	offset += (gint)len;
@@ -416,7 +405,7 @@ get_netsync_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *dat
 	/* skip version and command */
 	offset += 2;
 
-	size_bytes = dissect_uleb128( tvb, offset, &size );
+	size_bytes = tvb_get_varint( tvb, offset, FT_VARINT_MAX_LEN, &size );
 
 	/* the calculated size if for the data only, this doesn't
 	 * include the version (1 byte), command (1 byte),
diff --git a/epan/dwarf.c b/epan/dwarf.c
index 86d95e7eb8..8c7a145e9b 100644
--- a/epan/dwarf.c
+++ b/epan/dwarf.c
@@ -27,26 +27,6 @@
 #include "dwarf.h"
 
 gint
-dissect_uleb128(tvbuff_t *tvb, gint offset, guint64 *value)
-{
-    guint  start_offset = offset;
-    guint  shift = 0;
-    guint8 byte;
-
-    *value = 0;
-
-    do {
-        byte = tvb_get_guint8(tvb, offset);
-        offset += 1;
-
-        *value |= ((guint64)(byte & 0x7F) << shift);
-        shift += 7;
-    } while ((byte & 0x80) && (shift < 64));
-
-    return offset - start_offset;
-}
-
-gint
 dissect_leb128(tvbuff_t *tvb, gint offset, gint64 *value)
 {
     guint  start_offset = offset;
diff --git a/epan/dwarf.h b/epan/dwarf.h
index c948c5b315..211aca5713 100644
--- a/epan/dwarf.h
+++ b/epan/dwarf.h
@@ -25,7 +25,6 @@
 
 #include <glib.h>
 
-gint dissect_uleb128(tvbuff_t *tvb, gint offset, guint64 *value);
 gint dissect_leb128(tvbuff_t *tvb, gint offset, gint64 *value);
 
 #endif /* __DWARF_H__ */
diff --git a/epan/proto.h b/epan/proto.h
index cf42174486..2ef8cc7f89 100644
--- a/epan/proto.h
+++ b/epan/proto.h
@@ -525,6 +525,9 @@ WS_DLL_PUBLIC WS_NORETURN void proto_report_dissector_bug(const char *message);
 /* this can't collide with ENC_SEP_* because they can be used simultaneously */
 #define ENC_NUM_PREF    0x00200000
 
+/* Use varint format as described in Protobuf protocol
+ * https://developers.google.cn/protocol-buffers/docs/encoding
+ */
 #define ENC_VARINT_PROTOBUF      0x00000002
 
 /* For cases where a string encoding contains hex, bit-or one or more