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[zvt] the TLV container starts with an overall length field 

new function dissect_zvt_tlv_len(), use it for the total length
and for each tlv entry's length field

Change-Id: I2b7ba6939ddf0326b014c565ffbe5d16e3a88282
Reviewed-on: https://code.wireshark.org/review/9059
Reviewed-by: Martin Kaiser <wireshark@kaiser.cx>
This commit is contained in:
Martin Kaiser 2015-06-22 10:23:36 -07:00
parent ed8ad06ccc
commit 17ac3831d6
1 changed files with 47 additions and 20 deletions
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67
epan/dissectors/packet-zvt.c
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@ -153,6 +153,7 @@ static int hf_zvt_reg_cfg = -1;
static int hf_zvt_cc = -1;
static int hf_zvt_reg_svc_byte = -1;
static int hf_zvt_bitmap = -1;
static int hf_zvt_tlv_total_len = -1;
static int hf_zvt_tlv_tag = -1;
static int hf_zvt_tlv_len = -1;
@ -246,6 +247,37 @@ dissect_zvt_tlv_tag(tvbuff_t *tvb, gint offset,
}
static gint
dissect_zvt_tlv_len(tvbuff_t *tvb, gint offset,
packet_info *pinfo _U_, proto_tree *tree, int hf, guint16 *len)
{
guint16 _len;
gint len_bytes = 1;
_len = tvb_get_guint8(tvb, offset);
if (_len & 0x80) {
if ((_len & 0x03) == 1) {
len_bytes++;
_len = tvb_get_guint8(tvb, offset+1);
}
else if ((_len & 0x03) == 2) {
len_bytes += 2;
_len = tvb_get_ntohs(tvb, offset+1);
}
else {
/* XXX - expert info */
return -1;
}
}
proto_tree_add_uint(tree, hf, tvb, offset, len_bytes, _len);
if (len)
*len = _len;
return len_bytes;
}
static gint
dissect_zvt_tlv_container(tvbuff_t *tvb, gint offset,
packet_info *pinfo, proto_tree *tree)
@ -255,11 +287,16 @@ dissect_zvt_tlv_container(tvbuff_t *tvb, gint offset,
proto_tree *dat_obj_tree;
gint tag_len;
guint32 tag;
guint8 data_len_bytes = 1;
guint16 data_len;
gint total_len_bytes, data_len_bytes;
guint16 data_len = 0;
offset_start = offset;
total_len_bytes = dissect_zvt_tlv_len(tvb, offset, pinfo,
tree, hf_zvt_tlv_total_len, NULL);
if (total_len_bytes > 0)
offset += total_len_bytes;
while (tvb_captured_length_remaining(tvb, offset) > 0) {
dat_obj_tree = proto_tree_add_subtree(tree,
tvb, offset, -1, ett_zvt_tlv_dat_obj, &dat_obj_it,
@ -270,23 +307,10 @@ dissect_zvt_tlv_container(tvbuff_t *tvb, gint offset,
return offset - offset_start;
offset += tag_len;
data_len = tvb_get_guint8(tvb, offset);
if (data_len & 0x80) {
if ((data_len & 0x03) == 1) {
data_len_bytes++;
data_len = tvb_get_guint8(tvb, offset+1);
}
else if ((data_len & 0x03) == 2) {
data_len_bytes += 2;
data_len = tvb_get_ntohs(tvb, offset+1);
}
else {
/* XXX - expert info, exit */
}
}
proto_tree_add_uint(dat_obj_tree, hf_zvt_tlv_len,
tvb, offset, data_len_bytes, data_len);
offset += data_len_bytes;
data_len_bytes = dissect_zvt_tlv_len(tvb, offset, pinfo,
dat_obj_tree,hf_zvt_tlv_len, &data_len);
if (data_len_bytes > 0)
offset += data_len_bytes;
/* XXX - dissect the data-element */
offset += data_len;
@ -787,12 +811,15 @@ proto_register_zvt(void)
{ &hf_zvt_bitmap,
{ "Bitmap", "zvt.bitmap", FT_UINT8,
BASE_HEX|BASE_EXT_STRING, &bitmap_ext, 0, NULL, HFILL } },
{ &hf_zvt_tlv_total_len,
{ "Total length", "zvt.tlv.total_len",
FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL } },
{ &hf_zvt_tlv_tag,
{ "Tag", "zvt.tlv.tag", FT_UINT32,
BASE_HEX|BASE_EXT_STRING, &tlv_tags_ext, 0, NULL, HFILL } },
{ &hf_zvt_tlv_len,
{ "Length", "zvt.tlv.len",
FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } }
FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL } }
};
static ei_register_info ei[] = {