ref: 52ec96d00007df020f520b2003dec903220726b8
dir: /audio.c/
/* [MS-RDPEA]: Remote Desktop Protocol: Audio Output Virtual Channel Extension */
#include <u.h>
#include <libc.h>
#include "dat.h"
#include "fns.h"
/*
BUG requires RDPDR support...
[MS-RDPEA] "6 Appendix A: Product Behavior":
<1> Section 2.1: In Windows, the client advertises the static virtual
channel named "RDPDR", as defined in [MS-RDPEFS]. If that channel is
not advertised, the server will not issue any communication on the
"RDPSND" channel. Not supported on Windows XP and Windows Server
2003.
*/
static char rdpsnd[] = "RDPSND";
enum /* Audiomsg.type */
{
Awav= 2, /* WaveInfo PDU */
Awavack= 5, /* Wave Confirm PDU */
Aprobe= 6, /* Training PDU or Training Confirm PDU */
Afmt= 7, /* Client/Server Audio Formats and Version PDU */
/* 2.2.1 RDPSND PDU Header (SNDPROLOG) */
};
typedef struct Audiomsg Audiomsg;
struct Audiomsg
{
uint type;
uint nfmt; /* Afmt */
uint ack; /* Afmt */
uint ver; /* Afmt */
uchar *data; /* Afmt */
uint ndata; /* Afmt */
};
static int getaudiomsg(Audiomsg*,uchar*,int);
static int putaudiomsg(uchar*,int, Audiomsg*);
enum
{
FmtPCM= 0x01, /* WAVE_FORMAT_PCM */
FmtMP3= 0x55, /* WAVE_FORMAT_MPEGLAYER3 */
/* RFC2361 Appendix A */
};
void
audiovcfn(Rdp* c, uchar* a, uint nb)
{
Audiomsg r;
USED(c);
fprint(2, " A ");
if(getaudiomsg(&r, a, nb) < 0){
fprint(2, "audio: %r\n");
return;
}
fprint(2, " a%ud ", r.type);
}
/*
* 2.2.1 RDPSND PDU Header (SNDPROLOG)
* msgtype[1] pad[1] bodysize[2]
*
* 2.2.2.1 Server Audio Formats and Version PDU
* hdr[4] flags[4] vol[4] pitch[4] dgport[2] nfmt[2] ack[1] ver[2] pad[1] nfmt*(afmt[*])
*
* 2.2.2.1.1 Audio Format (AUDIO_FORMAT)
* ftag[2] nchan[2] samphz[4] avgbytehz[4] blocksz[2] sampbitsz[2] ndata[2] data[ndata]
*/
static int
getaudiomsg(Audiomsg* m, uchar* a, int nb)
{
ulong len;
if(nb < 4){
werrstr(Eshort);
return -1;
}
m->type = *a;
len = igets(a+2);
switch(m->type){
case Afmt:
if(len < 20 || nb < len+4){
werrstr(Eshort);
return -1;
}
m->nfmt = igets(a+18);
m->ack = a[20];
m->ver = igets(a+21);
m->data = a+24;
m->ndata = len-20;
return len+4;
}
werrstr("unrecognized audio msg type");
return -1;
}