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support extended size boxes, general cleanup 

svn path=/trunk/; revision=50040
This commit is contained in:
Martin Kaiser 2013-06-19 17:34:43 +00:00
parent a17358cf3f
commit 86c30e2abe
1 changed files with 46 additions and 22 deletions
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68
epan/dissectors/packet-mp4.c
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@ -45,6 +45,7 @@ static gint ett_mp4_box = -1;
static int hf_mp4_box_size = -1;
static int hf_mp4_box_type_str = -1;
static int hf_mp4_box_largesize = -1;
static int hf_mp4_full_box_ver = -1;
static int hf_mp4_ftyp_brand = -1;
static int hf_mp4_ftyp_ver = -1;
@ -52,7 +53,9 @@ static int hf_mp4_ftyp_add_brand = -1;
static int hf_mp4_mfhd_seq_num = -1;
/* a box must at least have a 32bit len field and a 32bit type */
#define MIN_BOX_LEN 8
#define MIN_BOX_SIZE 8
/* an extended box has the first length field set to 1 */
#define BOX_SIZE_EXTENDED 1
/* the box type is stored as four text characters
it is in network byte order and contains only printable characters
@ -86,6 +89,7 @@ static int hf_mp4_mfhd_seq_num = -1;
#define BOX_TYPE_TFHD MAKE_TYPE_VAL('t', 'f', 'h', 'd')
#define BOX_TYPE_TRUN MAKE_TYPE_VAL('t', 'r', 'u', 'n')
#define BOX_TYPE_MDAT MAKE_TYPE_VAL('m', 'd', 'a', 't')
#define BOX_TYPE_UDTA MAKE_TYPE_VAL('u', 'd', 't', 'a')
static const value_string box_types[] = {
@ -116,6 +120,7 @@ static const value_string box_types[] = {
{ BOX_TYPE_TFHD, "Track Fragment Header Box" },
{ BOX_TYPE_TRUN, "Track Fragment Run Box" },
{ BOX_TYPE_MDAT, "Media Data Box" },
{ BOX_TYPE_UDTA, "User Data Box" },
{ 0, NULL }
};
@ -177,54 +182,68 @@ dissect_mp4_ftyp_body(tvbuff_t *tvb, guint offset, guint len,
return offset-offset_start;
}
static gint
/* dissect a box, return its (standard or extended) length or 0 for error */
static guint64
dissect_mp4_box(guint32 parent_box_type _U_,
tvbuff_t *tvb, guint offset, packet_info *pinfo, proto_tree *tree)
{
guint offset_start;
guint box_len;
guint64 box_size;
guint32 box_type;
guint8 *box_type_str;
proto_item *pi;
proto_item *type_pi, *size_pi;
proto_tree *box_tree;
gint ret;
guint64 ret;
guint body_size;
offset_start = offset;
/* the following mechanisms are not supported for now
- extended size (size==1, largesize parameter)
- size==0, indicating that the box extends to the end of the file
- extended box types */
box_len = tvb_get_ntohl(tvb, offset);
if (box_len<MIN_BOX_LEN)
return -1;
box_size = (guint64)tvb_get_ntohl(tvb, offset);
if (box_size!=BOX_SIZE_EXTENDED && box_size<MIN_BOX_SIZE)
return 0;
box_type = tvb_get_ntohl(tvb, offset+4);
box_type_str = tvb_get_ephemeral_string(tvb, offset+4, 4);
pi = proto_tree_add_text(tree, tvb, offset, box_len, "%s (%s)",
type_pi = proto_tree_add_text(tree, tvb, offset, -1, "%s (%s)",
val_to_str_const(box_type, box_types, "unknown"), box_type_str);
box_tree = proto_item_add_subtree(pi, ett_mp4_box);
box_tree = proto_item_add_subtree(type_pi, ett_mp4_box);
proto_tree_add_item(box_tree, hf_mp4_box_size,
size_pi = proto_tree_add_item(box_tree, hf_mp4_box_size,
tvb, offset, 4, ENC_BIG_ENDIAN);
if (box_size==BOX_SIZE_EXTENDED)
proto_item_append_text(size_pi, " (actual size is in largesize)");
offset += 4;
proto_tree_add_item(box_tree, hf_mp4_box_type_str,
tvb, offset, 4, ENC_ASCII|ENC_NA);
offset += 4;
if (box_size==BOX_SIZE_EXTENDED) {
box_size = tvb_get_ntoh64(tvb, offset);
proto_tree_add_item(box_tree, hf_mp4_box_largesize,
tvb, offset, 8, ENC_BIG_ENDIAN);
offset += 8;
}
proto_item_set_len(type_pi, (gint)box_size);
body_size = box_size - (offset-offset_start);
/* XXX - check parent box if supplied */
switch (box_type) {
case BOX_TYPE_FTYP:
dissect_mp4_ftyp_body(tvb, offset, box_len-8, pinfo, box_tree);
dissect_mp4_ftyp_body(tvb, offset, body_size, pinfo, box_tree);
break;
case BOX_TYPE_MVHD:
dissect_mp4_mvhd_body(tvb, offset, box_len-8, pinfo, box_tree);
dissect_mp4_mvhd_body(tvb, offset, body_size, pinfo, box_tree);
break;
case BOX_TYPE_MFHD:
dissect_mp4_mfhd_body(tvb, offset, box_len-8, pinfo, box_tree);
dissect_mp4_mfhd_body(tvb, offset, body_size, pinfo, box_tree);
break;
case BOX_TYPE_MOOV:
case BOX_TYPE_MOOF:
@ -235,9 +254,10 @@ dissect_mp4_box(guint32 parent_box_type _U_,
case BOX_TYPE_MINF:
case BOX_TYPE_MVEX:
case BOX_TYPE_DINF:
while (offset-offset_start<box_len) {
case BOX_TYPE_UDTA:
while (offset-offset_start<box_size) {
ret = dissect_mp4_box(box_type, tvb, offset, pinfo, box_tree);
if (ret<=0)
if (ret==0)
break;
offset += ret;
}
@ -246,7 +266,7 @@ dissect_mp4_box(guint32 parent_box_type _U_,
break;
}
return box_len;
return box_size;
}
@ -257,14 +277,15 @@ dissect_mp4(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
guint32 box_type;
proto_item *pi;
proto_tree *mp4_tree;
gint ret;
guint64 ret;
/* to make sure that we have an mp4 file, we check that it starts with
a box of a known type
this should be safe as long as the dissector is only called for
please note that we do not allow the first box to be an extended box
this detection should be safe as long as the dissector is only called for
the video/mp4 mime type
when we read mp4 files directly, we might need stricter checks here */
if (tvb_reported_length(tvb)<MIN_BOX_LEN)
if (tvb_reported_length(tvb)<MIN_BOX_SIZE)
return 0;
box_type = tvb_get_ntohl(tvb, 4);
if (try_val_to_str(box_type, box_types) == NULL)
@ -279,7 +300,7 @@ dissect_mp4(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
while (tvb_reported_length_remaining(tvb, offset) > 0) {
ret = dissect_mp4_box(BOX_TYPE_NONE, tvb, offset, pinfo, mp4_tree);
if (ret<=0)
if (ret==0)
break;
offset += ret;
}
@ -297,6 +318,9 @@ proto_register_mp4(void)
{ &hf_mp4_box_type_str,
{ "Box type", "mp4.box.type_str", FT_STRING, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_mp4_box_largesize,
{ "Box size (largesize)", "mp4.box.largesize", FT_UINT64, BASE_DEC,
NULL, 0, NULL, HFILL } },
{ &hf_mp4_full_box_ver,
{ "Box version", "mp4.full_box.version", FT_UINT8, BASE_DEC,
NULL, 0, NULL, HFILL } },