/* [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 virtualchannel named "RDPDR", as defined in [MS-RDPEFS].  If that channel isnot advertised, the server will not issue any communication on the"RDPSND" channel.  Not supported on Windows XP and Windows Server2003.*/ 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 */};  voidaudiovcfn(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 intgetaudiomsg(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;}