rdesktop架构解析(RDP协议分析）
转载自： http://blog.csdn.net/songbohr/article/details/5309650
本文立足于rdesktop的架构层次进行解析，算是抛砖引玉，国内对RDP协议深入解析的资料到本文发布时为空白！
ps:昨天在nokia 5233系统下载了一个symRdp,国外RDP的应用已经遍地开花了。
调用层次：
rdp_--->sec_--->mcs_--->iso_--->tcp_
协议包编解码层次：
rdp_hdr->sec_hdr->mcs_hdr->iso_hdr->data，所有这些指针组成一个STREAM.
/* Parser state */
typedef struct stream
{
unsigned char *p; // 临时指针变量，用于计算定位。
unsigned char *end; // TCP/IP数据的结束位置
unsigned char *data; // TCP/IP数据的起始位置，是申请的一段内存，只当数据尺寸大于size时，进行realloc增大，不缩小
unsigned int size; // TCP/IP数据的尺寸大小
//以上是tcp数据管理变量
/* Offsets of various headers */
unsigned char *iso_hdr; // TCP/IP数据包中iso协议控制头的位置
unsigned char *mcs_hdr; // TCP/IP数据包中mcs协议控制头的位置
unsigned char *sec_hdr; // TCP/IP数据包中sec协议控制头的位置
unsigned char *rdp_hdr; // TCP/IP数据包中rdp协议控制头的位置
unsigned char *channel_hdr;
}
*STREAM;
ISO控制头：7字节
MCS控制头：8字节
SEC控制头：0（如果已经获得许可证—通信协定）、4（未获许可）或12（进行加密时）字节
由SEC头控制的数据段即是RDP的主要数据，一般进行了加密。
主过程：
1、rdp_connect： 按照调用层次依次调用sec_connect……，然后调用rdp_send_logon_info发送登录请求验证信息.其中rdp_send_logon_info调用sec_init初始化数据包,调用sec_send发送数据包，根据flags（包含加密标识）调用加密处理逻辑.
/* Establish a connection up to the RDP layer */
BOOL
rdp_connect(char *server, uint32 flags, char *domain, char *password,
char *command, char *directory)
{
if (!sec_connect(server, g_username))
return False;
rdp_send_logon_info(flags, domain, g_username, password, command, directory);
return True;
}
2、然后进入rdp_main_loop循环，调用rdp_recv,根据触发的事件类型做相应处理。
/* Process incoming packets */
/* nevers gets out of here till app is done */
void
rdp_main_loop(BOOL * deactivated, uint32 * ext_disc_reason)
{
while (rdp_loop(deactivated, ext_disc_reason))
;
}
/* used in uiports and rdp_main_loop, processes the rdp packets waiting */
BOOL
rdp_loop(BOOL * deactivated, uint32 * ext_disc_reason)
{
uint8 type;
BOOL disc = False; /* True when a disconnect PDU was received */
BOOL cont = True;
STREAM s;
while (cont)
{
s = rdp_recv(&type);
if (s == NULL)
return False;
switch (type)
{
case RDP_PDU_DEMAND_ACTIVE:
process_demand_active(s);
*deactivated = False;
break;
case RDP_PDU_DEACTIVATE:
DEBUG(("RDP_PDU_DEACTIVATE\n"));
*deactivated = True;
break;
case RDP_PDU_REDIRECT:
return process_redirect_pdu(s);
break;
case RDP_PDU_DATA:
disc = process_data_pdu(s, ext_disc_reason);
break;
case 0:
break;
default:
unimpl("PDU %d\n", type);
}
if (disc)
return False;
cont = g_next_packet < s->end;
}
return True;
}
3、rdp_disconnect，按照调用层次依次调用sec_disconnect……断开。特殊的，在iso_disconnect中首先调用iso_send_msg(ISO_PDU_DR)发送PDU消息包，然后再调用tcp_disconnect 断开连接。
/* Disconnect from the RDP layer */
void
rdp_disconnect(void)
{
sec_disconnect();
}
/* Disconnect from the ISO layer */
void
iso_disconnect(void)
{
iso_send_msg(ISO_PDU_DR);
tcp_disconnect();
}
/* ISO PDU codes */
enum ISO_PDU_CODE
{
ISO_PDU_CR = 0xE0, /* Connection Request */
ISO_PDU_CC = 0xD0, /* Connection Confirm */
ISO_PDU_DR = 0x80, /* Disconnect Request */
ISO_PDU_DT = 0xF0, /* Data */
ISO_PDU_ER = 0x70 /* Error */
};
/* MCS PDU codes */
enum MCS_PDU_TYPE
{
MCS_EDRQ = 1, /* Erect Domain Request */
MCS_DPUM = 8, /* Disconnect Provider Ultimatum */
MCS_AURQ = 10, /* Attach User Request */
MCS_AUCF = 11, /* Attach User Confirm */
MCS_CJRQ = 14, /* Channel Join Request */
MCS_CJCF = 15, /* Channel Join Confirm */
MCS_SDRQ = 25, /* Send Data Request */
MCS_SDIN = 26 /* Send Data Indication */
};
protocal interface(协议接口)：
/* rdp.c */
void rdp_out_unistr(STREAM s, char *string, int len);
int rdp_in_unistr(STREAM s, char *string, int uni_len);
void rdp_send_input(uint32 time, uint16 message_type, uint16 device_flags, uint16 param1,
uint16 param2);
void rdp_send_client_window_status(int status);
void process_colour_pointer_pdu(STREAM s);
void process_cached_pointer_pdu(STREAM s);
void process_system_pointer_pdu(STREAM s);
void process_bitmap_updates(STREAM s);
void process_palette(STREAM s);
void process_disconnect_pdu(STREAM s, uint32 * ext_disc_reason);
void rdp_main_loop(BOOL * deactivated, uint32 * ext_disc_reason);
BOOL rdp_loop(BOOL * deactivated, uint32 * ext_disc_reason);
BOOL rdp_connect(char *server, uint32 flags, char *domain, char *password, char *command,
char *directory);
BOOL rdp_reconnect(char *server, uint32 flags, char *domain, char *password, char *command,
char *directory, char *cookie);
void rdp_reset_state(void);
void rdp_disconnect(void);
/* rdpdr.c */
int get_device_index(RD_NTHANDLE handle);
void convert_to_unix_filename(char *filename);
BOOL rdpdr_init(void);
void rdpdr_add_fds(int *n, fd_set * rfds, fd_set * wfds, struct timeval *tv, BOOL * timeout);
struct async_iorequest *rdpdr_remove_iorequest(struct async_iorequest *prev,
struct async_iorequest *iorq);
void rdpdr_check_fds(fd_set * rfds, fd_set * wfds, BOOL timed_out);
BOOL rdpdr_abort_io(uint32 fd, uint32 major, RD_NTSTATUS status);
/* rdpsnd.c */
void rdpsnd_send_completion(uint16 tick, uint8 packet_index);
BOOL rdpsnd_init(void);
/* rdpsnd_oss.c */
BOOL wave_out_open(void);
void wave_out_close(void);
BOOL wave_out_format_supported(WAVEFORMATEX * pwfx);
BOOL wave_out_set_format(WAVEFORMATEX * pwfx);
void wave_out_volume(uint16 left, uint16 right);
void wave_out_write(STREAM s, uint16 tick, uint8 index);
void wave_out_play(void);
/* secure.c */
void sec_hash_48(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2, uint8 salt);
void sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2);
void buf_out_uint32(uint8 * buffer, uint32 value);
void sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data,
int datalen);
void sec_decrypt(uint8 * data, int length);
STREAM sec_init(uint32 flags, int maxlen);
void sec_send_to_channel(STREAM s, uint32 flags, uint16 channel);
void sec_send(STREAM s, uint32 flags);
void sec_process_mcs_data(STREAM s);
STREAM sec_recv(uint8 * rdpver);
BOOL sec_connect(char *server, char *username);
BOOL sec_reconnect(char *server);
void sec_disconnect(void);
void sec_reset_state(void);
/* serial.c */
int serial_enum_devices(uint32 * id, char *optarg);
BOOL serial_get_event(RD_NTHANDLE handle, uint32 * result);
BOOL serial_get_timeout(RD_NTHANDLE handle, uint32 length, uint32 * timeout, uint32 * itv_timeout);
/* tcp.c */
STREAM tcp_init(uint32 maxlen);
void tcp_send(STREAM s);
STREAM tcp_recv(STREAM s, uint32 length);
BOOL tcp_connect(char *server);
void tcp_disconnect(void);
char *tcp_get_address(void);
void tcp_reset_state(void);
ui interface（UI接口）
/* xkeymap.c */
BOOL xkeymap_from_locale(const char *locale);
FILE *xkeymap_open(const char *filename);
void xkeymap_init(void);
BOOL handle_special_keys(uint32 keysym, unsigned int state, uint32 ev_time, BOOL pressed);
key_translation xkeymap_translate_key(uint32 keysym, unsigned int keycode, unsigned int state);
void xkeymap_send_keys(uint32 keysym, unsigned int keycode, unsigned int state, uint32 ev_time,
BOOL pressed, uint8 nesting);
uint16 xkeymap_translate_button(unsigned int button);
char *get_ksname(uint32 keysym);
void save_remote_modifiers(uint8 scancode);
void restore_remote_modifiers(uint32 ev_time, uint8 scancode);
void ensure_remote_modifiers(uint32 ev_time, key_translation tr);
unsigned int read_keyboard_state(void);
uint16 ui_get_numlock_state(unsigned int state);
void reset_modifier_keys(void);
void rdp_send_scancode(uint32 time, uint16 flags, uint8 scancode);
/* xwin.c */
BOOL get_key_state(unsigned int state, uint32 keysym);
BOOL ui_init(void);
void ui_deinit(void);
BOOL ui_create_window(void);
void ui_resize_window(void);
void ui_destroy_window(void);
void xwin_toggle_fullscreen(void);
int ui_select(int rdp_socket);
void ui_move_pointer(int x, int y);
RD_HBITMAP ui_create_bitmap(int width, int height, uint8 * data);
void ui_paint_bitmap(int x, int y, int cx, int cy, int width, int height, uint8 * data);
void ui_destroy_bitmap(RD_HBITMAP bmp);
RD_HGLYPH ui_create_glyph(int width, int height, uint8 * data);
void ui_destroy_glyph(RD_HGLYPH glyph);
RD_HCURSOR ui_create_cursor(unsigned int x, unsigned int y, int width, int height, uint8 * andmask,
uint8 * xormask);
void ui_set_cursor(RD_HCURSOR cursor);
void ui_destroy_cursor(RD_HCURSOR cursor);
void ui_set_null_cursor(void);
RD_HCOLOURMAP ui_create_colourmap(COLOURMAP * colours);
void ui_destroy_colourmap(RD_HCOLOURMAP map);
void ui_set_colourmap(RD_HCOLOURMAP map);
void ui_set_clip(int x, int y, int cx, int cy);
void ui_reset_clip(void);
void ui_bell(void);
void ui_destblt(uint8 opcode, int x, int y, int cx, int cy);
void ui_patblt(uint8 opcode, int x, int y, int cx, int cy, BRUSH * brush, int bgcolour,
int fgcolour);
void ui_screenblt(uint8 opcode, int x, int y, int cx, int cy, int srcx, int srcy);
void ui_memblt(uint8 opcode, int x, int y, int cx, int cy, RD_HBITMAP src, int srcx, int srcy);
void ui_triblt(uint8 opcode, int x, int y, int cx, int cy, RD_HBITMAP src, int srcx, int srcy,
BRUSH * brush, int bgcolour, int fgcolour);
void ui_line(uint8 opcode, int startx, int starty, int endx, int endy, PEN * pen);
void ui_rect(int x, int y, int cx, int cy, int colour);
void ui_polygon(uint8 opcode, uint8 fillmode, POINT * point, int npoints, BRUSH * brush,
int bgcolour, int fgcolour);
void ui_polyline(uint8 opcode, POINT * points, int npoints, PEN * pen);
void ui_ellipse(uint8 opcode, uint8 fillmode, int x, int y, int cx, int cy, BRUSH * brush,
int bgcolour, int fgcolour);
void ui_draw_glyph(int mixmode, int x, int y, int cx, int cy, RD_HGLYPH glyph, int srcx, int srcy,
int bgcolour, int fgcolour);
void ui_draw_text(uint8 font, uint8 flags, uint8 opcode, int mixmode, int x, int y, int clipx,
int clipy, int clipcx, int clipcy, int boxx, int boxy, int boxcx, int boxcy,
BRUSH * brush, int bgcolour, int fgcolour, uint8 * text, uint8 length);
void ui_desktop_save(uint32 offset, int x, int y, int cx, int cy);
void ui_desktop_restore(uint32 offset, int x, int y, int cx, int cy);
void ui_begin_update(void);
void ui_end_update(void);
void ui_seamless_begin(BOOL hidden);
void ui_seamless_hide_desktop(void);
void ui_seamless_unhide_desktop(void);
void ui_seamless_toggle(void);
void ui_seamless_create_window(unsigned long id, unsigned long group, unsigned long parent,
unsigned long flags);
void ui_seamless_destroy_window(unsigned long id, unsigned long flags);
void ui_seamless_move_window(unsigned long id, int x, int y, int width, int height,
unsigned long flags);
void ui_seamless_restack_window(unsigned long id, unsigned long behind, unsigned long flags);
void ui_seamless_settitle(unsigned long id, const char *title, unsigned long flags);
void ui_seamless_setstate(unsigned long id, unsigned int state, unsigned long flags);
void ui_seamless_syncbegin(unsigned long flags);
void ui_seamless_ack(unsigned int serial);
其中，ui_select是整个UI的核心，负责UI调度。
cache interface(缓存接口）
/* bitmap.c */
BOOL bitmap_decompress(uint8 * output, int width, int height, uint8 * input, int size, int Bpp);
/* cache.c */
void cache_rebuild_bmpcache_linked_list(uint8 id, sint16 * idx, int count);
void cache_bump_bitmap(uint8 id, uint16 idx, int bump);
void cache_evict_bitmap(uint8 id);
RD_HBITMAP cache_get_bitmap(uint8 id, uint16 idx);
void cache_put_bitmap(uint8 id, uint16 idx, RD_HBITMAP bitmap);
void cache_save_state(void);
FONTGLYPH *cache_get_font(uint8 font, uint16 character);
void cache_put_font(uint8 font, uint16 character, uint16 offset, uint16 baseline, uint16 width,
uint16 height, RD_HGLYPH pixmap);
DATABLOB *cache_get_text(uint8 cache_id);
void cache_put_text(uint8 cache_id, void *data, int length);
uint8 *cache_get_desktop(uint32 offset, int cx, int cy, int bytes_per_pixel);
void cache_put_desktop(uint32 offset, int cx, int cy, int scanline, int bytes_per_pixel,
uint8 * data);
RD_HCURSOR cache_get_cursor(uint16 cache_idx);
void cache_put_cursor(uint16 cache_idx, RD_HCURSOR cursor);
licence证书处理
/* licence.c */
void licence_process(STREAM s);
主进程函数
/* rdesktop.c */
int main(int argc, char *argv[]);
void generate_random(uint8 * random);
void *xmalloc(int size);
char *xstrdup(const char *s);
void *xrealloc(void *oldmem, int size);
void xfree(void *mem);
void error(char *format, ...);
void warning(char *format, ...);
void unimpl(char *format, ...);
void hexdump(unsigned char *p, unsigned int len);
次序处理：
/* orders.c */
void process_orders(STREAM s, uint16 num_orders);
void reset_order_state(void);
协议数据包：
128-bit encryption enabled
Sending encrypted packet:
0000 00 00 00 00 33 00 00 00 00 00 1a 00 00 00 00 00 ....3...........
0010 00 00 00 00 41 00 64 00 6d 00 69 00 6e 00 69 00 ....A.d.m.i.n.i.
0020 73 00 74 00 72 00 61 00 74 00 6f 00 72 00 00 00 s.t.r.a.t.o.r...
0030 00 00 00 00 00 00 ......
Connection successful.
Sending encrypted packet:
0000 22 00 17 00 ec 03 00 00 00 00 00 01 14 00 1c 00 "...............
0010 00 00 01 00 00 00 11 4e 7a 4b 01 80 00 08 cf 01 .......NzK......
0020 91 00 ..
Sending encrypted packet:
0000 22 00 17 00 ec 03 00 00 00 00 00 01 14 00 1c 00 "...............
0010 00 00 01 00 00 00 12 4e 7a 4b 01 80 00 08 cf 01 .......NzK......
0020 91 00 ..
RDP packet (type 1):
0000 67 01 11 00 ea 03 ea 03 01 00 04 00 51 01 52 44 g...........Q.RD
0010 50 00 0d 00 00 00 09 00 08 00 ea 03 65 e3 01 00 P...........e...
0020 18 00 01 00 03 00 00 02 00 00 00 00 1d 04 00 00 ................
0030 00 00 00 00 01 01 14 00 08 00 02 00 00 00 16 00 ................
0040 28 00 01 00 00 00 6c 96 33 b7 01 00 00 00 95 a4 (.....l.3.......
0050 84 80 b0 7d 38 84 b8 5b c4 e1 f4 96 33 b7 ea e8 ...}8..[....3...
0060 84 80 20 02 c9 85 0e 00 04 00 02 00 1c 00 08 00 .. .............
0070 01 00 01 00 01 00 c0 03 e9 02 00 00 01 00 01 00 ................
0080 00 00 01 00 00 00 03 00 58 00 00 00 00 00 00 00 ........X.......
0090 00 00 00 00 00 00 00 00 00 00 40 42 0f 00 01 00 ..........@B....
00a0 14 00 00 00 01 00 00 00 22 00 01 01 01 01 01 00 ........".......
00b0 00 01 01 01 01 01 00 00 00 01 01 01 01 01 01 01 ................
00c0 01 00 01 01 01 01 00 00 00 00 a1 06 00 00 40 42 ..............@B
00d0 0f 00 40 42 0f 00 01 00 00 00 00 00 00 00 0a 00 ..@B............
00e0 08 00 06 00 00 00 12 00 08 00 01 00 00 00 08 00 ................
00f0 0a 00 01 00 19 00 19 00 0d 00 58 00 35 00 00 00 ..........X.5...
0100 a1 06 00 00 40 42 0f 00 0c 96 33 b7 75 7a 6f b7 [email protected].
0110 00 40 43 e1 48 3c 70 b7 40 96 33 b7 04 00 00 00 [email protected].J.P!D
0020 21 23 01 00 00 15 4a 01 50 3f 40 3f 01 ff 01 00 !#....J.P?@?....
0030 15 02 01 50 40 40 40 02 00 15 02 01 50 40 40 40 ...P@@@.....P@@@
0040 03 00 15 02 01 50 40 40 40 01 00 15 0a 01 50 40 .....P@@@.....P@
0050 2f 40 ef 04 00 45 4a 05 12 01 22 01 12 01 11 00 /@...EJ...".....
0060 2f 00 15 4a 01 50 11 1c 11 0b d1 05 00 /..J.P.......
MEMBLT(op=0xcc,x=319,y=297,cx=63,cy=5,id=1,idx=0)
MEMBLT(op=0xcc,x=382,y=297,cx=64,cy=5,id=1,idx=1)
MEMBLT(op=0xcc,x=446,y=297,cx=64,cy=5,id=1,idx=2)
MEMBLT(op=0xcc,x=510,y=297,cx=64,cy=5,id=1,idx=3)
MEMBLT(op=0xcc,x=574,y=297,cx=64,cy=5,id=1,idx=1)
MEMBLT(op=0xcc,x=638,y=297,cx=47,cy=5,id=1,idx=4)
MEMBLT(op=0xcc,x=274,y=297,cx=17,cy=5,id=1,idx=4)
MEMBLT(op=0xcc,x=291,y=297,cx=28,cy=5,id=1,idx=5)
RDP packet (type 7):
0000 1e 00 17 00 ea 03 ea 03 01 00 04 02 1e 00 02 00 ................
0010 00 00 00 00 85 7e 01 00 d5 f5 19 0b 20 01 .....~...... .
DESKSAVE(l=271,t=200,r=687,b=343,off=0,op=1)
RDP packet (type 6):
0000 0d 00 16 00 ea 03 ea 03 01 00 01 00 00 .............
Disconnecting...