USB Audio: Split AS format type dissection by version

Format types differ quite a lot between USB Audio version 1 and 2 thus
it is good to clearly separate the dissection into separate functions.

So far only the format type 1 of version 2 USB Audio Audio Streaming is
dissected.

Ping-Bug: 15503
Change-Id: I40544c7efb05810e2281248d1d1d33951b3b42a9
Reviewed-on: https://code.wireshark.org/review/33065
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 51 insertions, 9 deletions

diff --git a/epan/dissectors/packet-usb-audio.c b/epan/dissectors/packet-usb-audio.c
index 4c270f7c0a..1469dc844e 100644
--- a/epan/dissectors/packet-usb-audio.c
+++ b/epan/dissectors/packet-usb-audio.c
@@ -262,6 +262,7 @@ static int hf_as_if_ft_formattype = -1;
 static int hf_as_if_ft_maxbitrate = -1;
 static int hf_as_if_ft_nrchannels = -1;
 static int hf_as_if_ft_subframesize = -1;
+static int hf_as_if_ft_subslotsize = -1;
 static int hf_as_if_ft_bitresolution = -1;
 static int hf_as_if_ft_samplesperframe = -1;
 static int hf_as_if_ft_samfreqtype = -1;
@@ -1304,19 +1305,13 @@ dissect_as_if_general_body(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_,
 }
 
 static gint
-dissect_as_if_format_type_body(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_,
-        proto_tree *tree, usb_conv_info_t *usb_conv_info)
+dissect_as_if_format_type_ver1_body(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_,
+        proto_tree *tree, audio_conv_info_t *audio_conv_info _U_)
 {
-    audio_conv_info_t *audio_conv_info;
-    gint               offset_start;
+    gint   offset_start;
     guint8 SamFreqType;
     guint8 format_type;
 
-    /* the caller has already checked that usb_conv_info!=NULL */
-    audio_conv_info = (audio_conv_info_t *)usb_conv_info->class_data;
-    if (!audio_conv_info)
-        return 0;
-
     offset_start = offset;
 
     proto_tree_add_item(tree, hf_as_if_ft_formattype, tvb, offset, 1, ENC_LITTLE_ENDIAN);
@@ -1384,6 +1379,50 @@ dissect_as_if_format_type_body(tvbuff_t *tvb, gint offset, packet_info *pinfo _U
 }
 
 static gint
+dissect_as_if_format_type_ver2_body(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_,
+        proto_tree *tree, audio_conv_info_t *audio_conv_info _U_)
+{
+    gint   offset_start;
+    guint8 format_type;
+
+    offset_start = offset;
+
+    proto_tree_add_item(tree, hf_as_if_ft_formattype, tvb, offset, 1, ENC_LITTLE_ENDIAN);
+    format_type = tvb_get_guint8(tvb, offset);
+    offset++;
+
+    if (format_type==1) {
+        proto_tree_add_item(tree, hf_as_if_ft_subslotsize, tvb, offset, 1, ENC_LITTLE_ENDIAN);
+        offset += 1;
+
+        proto_tree_add_item(tree, hf_as_if_ft_bitresolution, tvb, offset, 1, ENC_LITTLE_ENDIAN);
+        offset += 1;
+    }
+
+    return offset-offset_start;
+}
+
+static gint
+dissect_as_if_format_type_body(tvbuff_t *tvb, gint offset, packet_info *pinfo,
+        proto_tree *tree, usb_conv_info_t *usb_conv_info)
+{
+    audio_conv_info_t *audio_conv_info;
+
+    /* the caller has already checked that usb_conv_info!=NULL */
+    audio_conv_info = (audio_conv_info_t *)usb_conv_info->class_data;
+    if (!audio_conv_info)
+        return 0;
+
+    if (audio_conv_info->ver_major==1) {
+        return dissect_as_if_format_type_ver1_body(tvb, offset, pinfo, tree, audio_conv_info);
+    } else if (audio_conv_info->ver_major==2) {
+        return dissect_as_if_format_type_ver2_body(tvb, offset, pinfo, tree, audio_conv_info);
+    }
+
+    return 0;
+}
+
+static gint
 dissect_usb_audio_descriptor(tvbuff_t *tvb, packet_info *pinfo,
         proto_tree *tree, void *data)
 {
@@ -2275,6 +2314,9 @@ proto_register_usb_audio(void)
         { &hf_as_if_ft_subframesize,
             { "Subframe Size", "usbaudio.as_if_ft.bSubframeSize",
               FT_UINT8, BASE_DEC, NULL, 0x00, "bSubframeSize", HFILL }},
+        { &hf_as_if_ft_subslotsize,
+            { "Subslot Size", "usbaudio.as_if_ft.bSubslotSize",
+              FT_UINT8, BASE_DEC, NULL, 0x00, "bSubslotSize", HFILL }},
         { &hf_as_if_ft_bitresolution,
             { "Bit Resolution", "usbaudio.as_if_ft.bBitResolution",
               FT_UINT8, BASE_DEC, NULL, 0x00, "bBitResolution", HFILL }},