rdp5 decompression, but only <= 8-bit depth.

git-svn-id: svn://svn.code.sf.net/p/rdesktop/code/trunk/rdesktop@686 423420c4-83ab-492f-b58f-81f9feb106b5

mppc.c

@@ -3,7 +3,7 @@
 
 #include "rdesktop.h"
 
-/* mppc-like??? decompression               */
+/* mppc decompression                       */
 /* http://www.faqs.org/rfcs/rfc2118.html    */
 
 /* TODO: research the below statements      */
@@ -18,11 +18,15 @@
 /* already paying royalties                 */
 /* through the CAL licenses?                */
 
-/* the dictionary is empty when init. like  */
+/* as the rfc states the algorithm seems to */
-/* LZ78,  which is not patented             */
+/* be LZ77 with a sliding buffer            */
+/* that is empty at init.                   */
+
+/* as of my limited knowledge these patents */
+/* has expired.                             */
 
 
-RDPCOMP mppc_dict;
+RDPCOMP g_mppc_dict;
 
 int
 mppc_expand(uint8 * data, uint32 clen, uint8 ctype, uint32 * roff, uint32 * rlen)
@@ -33,7 +37,7 @@ mppc_expand(uint8 * data, uint32 clen, uint8 ctype, uint32 * roff, uint32 * rlen
 	int match_len;
 	int old_offset, match_bits;
 
-	signed char *dict = &(mppc_dict.hist);
+	signed char *dict = &(g_mppc_dict.hist);
 
 	if ((ctype & RDP_MPPC_COMPRESSED) == 0)
 	{
@@ -44,19 +48,19 @@ mppc_expand(uint8 * data, uint32 clen, uint8 ctype, uint32 * roff, uint32 * rlen
 
 	if ((ctype & RDP_MPPC_RESET) != 0)
 	{
-		mppc_dict.roff = 0;
+		g_mppc_dict.roff = 0;
 	}
 
 	if ((ctype & RDP_MPPC_FLUSH) != 0)
 	{
 		memset(dict, 0, RDP_MPPC_DICT_SIZE);
-		mppc_dict.roff = 0;
+		g_mppc_dict.roff = 0;
 	}
 
 	*roff = 0;
 	*rlen = 0;
 
-	walker = mppc_dict.roff;
+	walker = g_mppc_dict.roff;
 
 	next_offset = walker;
 	old_offset = next_offset;
@@ -267,7 +271,7 @@ mppc_expand(uint8 * data, uint32 clen, uint8 ctype, uint32 * roff, uint32 * rlen
 	while (1);
 
 	/* store history offset */
-	mppc_dict.roff = next_offset;
+	g_mppc_dict.roff = next_offset;
 
 	*roff = old_offset;
 	*rlen = next_offset - old_offset;

rdp.c

@@ -38,7 +38,7 @@ extern BOOL g_bitmap_cache;
 uint8 *g_next_packet;
 uint32 g_rdp_shareid;
 
-extern RDPCOMP mppc_dict;
+extern RDPCOMP g_mppc_dict;
 
 #if WITH_DEBUG
 static uint32 g_packetno;
@@ -176,16 +176,16 @@ rdp_send_logon_info(uint32 flags, char *domain, char *user,
 	time_t t = time(NULL);
 	time_t tzone;
 
+#if 0
+	/* enable rdp compression */
+	/* some problems still exist with rdp5 */
+	flags |= RDP_COMPRESSION;
+#endif
+
 	if (!g_use_rdp5 || 1 == g_server_rdp_version)
 	{
 		DEBUG_RDP5(("Sending RDP4-style Logon packet\n"));
 
-#if 0
-		/* enable rdp compression */
-		/* decompression also works with rdp5 */
-		/* but there are some unknown opcodes */
-		flags |= RDP_COMPRESSION;
-#endif
 		s = sec_init(sec_flags, 18 + len_domain + len_user + len_password
 			     + len_program + len_directory + 10);
 
@@ -962,8 +962,7 @@ process_data_pdu(STREAM s, uint32 * ext_disc_reason)
 
 	uint32 roff, rlen;
 
-	struct stream *ns = &(mppc_dict.ns);
+	struct stream *ns = &(g_mppc_dict.ns);
-	uint8 *dict = (mppc_dict.hist);
 
 	in_uint8s(s, 6);	/* shareid, pad, streamid */
 	in_uint16(s, len);
@@ -978,18 +977,14 @@ process_data_pdu(STREAM s, uint32 * ext_disc_reason)
 		if (mppc_expand(s->p, clen, ctype, &roff, &rlen) == -1)
 			error("error while decompressing packet\n");
 
-		len -= 18;
+		//len -= 18;
-
-		/* this should never happen */
-		if (len != rlen)
-			error("decompression error len != rlen\n");
 
 		/* allocate memory and copy the uncompressed data into the temporary stream */
-		ns->data = xrealloc(ns->data, len);
+		ns->data = xrealloc(ns->data, rlen);
 
-		memcpy((ns->data), (unsigned char *) (mppc_dict.hist + roff), len);
+		memcpy((ns->data), (unsigned char *) (g_mppc_dict.hist + roff), rlen);
 
-		ns->size = len;
+		ns->size = rlen;
 		ns->end = (ns->data + ns->size);
 		ns->p = ns->data;
 		ns->rdp_hdr = ns->p;

rdp5.c

@@ -23,13 +23,19 @@
 
 extern uint8 *g_next_packet;
 
+extern RDPCOMP g_mppc_dict;
+
 void
 rdp5_process(STREAM s, BOOL encryption)
 {
 	uint16 length, count, x, y;
-	uint8 type;
+	uint8 type, ctype;
 	uint8 *next;
 
+	uint32 roff, rlen;
+	struct stream *ns = &(g_mppc_dict.ns);
+	struct stream *ts;
+
 	if (encryption)
 	{
 		in_uint8s(s, 8);	/* signature */
@@ -44,9 +50,40 @@ rdp5_process(STREAM s, BOOL encryption)
 	while (s->p < s->end)
 	{
 		in_uint8(s, type);
-		in_uint16_le(s, length);
+		if (type & RDP_COMPRESSION)
+		{
+			in_uint8(s, ctype);
+			in_uint16_le(s, length);
+			type ^= RDP_COMPRESSION;
+		}
+		else
+		{
+			ctype = 0;
+			in_uint16_le(s, length);
+		}
 		g_next_packet = next = s->p + length;
 
+		if (ctype & RDP_MPPC_COMPRESSED)
+		{
+
+			if (mppc_expand(s->p, length, ctype, &roff, &rlen) == -1)
+				error("error while decompressing packet\n");
+
+			/* allocate memory and copy the uncompressed data into the temporary stream */
+			ns->data = xrealloc(ns->data, rlen);
+
+			memcpy((ns->data), (unsigned char *) (g_mppc_dict.hist + roff), rlen);
+
+			ns->size = rlen;
+			ns->end = (ns->data + ns->size);
+			ns->p = ns->data;
+			ns->rdp_hdr = ns->p;
+
+			ts = ns;
+		}
+		else
+			ts = s;
+
 		switch (type)
 		{
 				/* Thanks to Jeroen Meijer <jdmeijer at yahoo
@@ -54,16 +91,16 @@ rdp5_process(STREAM s, BOOL encryption)
 				   most of the opcodes here. Especially opcode
 				   8! :) */
 			case 0:	/* orders */
-				in_uint16_le(s, count);
+				in_uint16_le(ts, count);
-				process_orders(s, count);
+				process_orders(ts, count);
 				break;
 			case 1:	/* bitmap update (???) */
-				in_uint8s(s, 2);	/* part length */
+				in_uint8s(ts, 2);	/* part length */
-				process_bitmap_updates(s);
+				process_bitmap_updates(ts);
 				break;
 			case 2:	/* palette */
-				in_uint8s(s, 2);	/* uint16 = 2 */
+				in_uint8s(ts, 2);	/* uint16 = 2 */
-				process_palette(s);
+				process_palette(ts);
 				break;
 			case 3:	/* probably an palette with offset 3. Weird */
 				break;
@@ -71,16 +108,16 @@ rdp5_process(STREAM s, BOOL encryption)
 				ui_set_null_cursor();
 				break;
 			case 8:
-				in_uint16_le(s, x);
+				in_uint16_le(ts, x);
-				in_uint16_le(s, y);
+				in_uint16_le(ts, y);
-				if (s_check(s))
+				if (s_check(ts))
 					ui_move_pointer(x, y);
 				break;
 			case 9:
-				process_colour_pointer_pdu(s);
+				process_colour_pointer_pdu(ts);
 				break;
 			case 10:
-				process_cached_pointer_pdu(s);
+				process_cached_pointer_pdu(ts);
 				break;
 			default:
 				unimpl("RDP5 opcode %d\n", type);