/** * xrdp: A Remote Desktop Protocol server. * * Copyright (C) Jay Sorg 2006-2013 * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * channel layer */ #if defined(HAVE_CONFIG_H) #include #endif #include "libxrdp.h" /* todo, move these to constants.h */ //#define CHANNEL_CHUNK_LENGTH 1600 /* todo, why is this so small? */ #define CHANNEL_CHUNK_LENGTH 8192 #define CHANNEL_FLAG_FIRST 0x01 #define CHANNEL_FLAG_LAST 0x02 #define CHANNEL_FLAG_SHOW_PROTOCOL 0x10 /*****************************************************************************/ /* returns pointer or nil on error */ static struct mcs_channel_item * xrdp_channel_get_item(struct xrdp_channel *self, int channel_id) { struct mcs_channel_item *channel; if (self->mcs_layer->channel_list == NULL) { g_writeln("xrdp_channel_get_item - No channel initialized"); return NULL ; } channel = (struct mcs_channel_item *) list_get_item(self->mcs_layer->channel_list, channel_id); return channel; } /*****************************************************************************/ struct xrdp_channel * xrdp_channel_create(struct xrdp_sec *owner, struct xrdp_mcs *mcs_layer) { struct xrdp_channel *self; self = (struct xrdp_channel *)g_malloc(sizeof(struct xrdp_channel), 1); self->sec_layer = owner; self->mcs_layer = mcs_layer; return self; } /*****************************************************************************/ /* returns error */ void xrdp_channel_delete(struct xrdp_channel *self) { if (self == 0) { return; } g_memset(self, 0, sizeof(struct xrdp_channel)); g_free(self); } /*****************************************************************************/ /* returns error */ int xrdp_channel_init(struct xrdp_channel *self, struct stream *s) { if (xrdp_sec_init(self->sec_layer, s) != 0) { return 1; } s_push_layer(s, channel_hdr, 8); return 0; } /*****************************************************************************/ /* returns error */ /* This sends data out to the secure layer. */ int xrdp_channel_send(struct xrdp_channel *self, struct stream *s, int channel_id, int total_data_len, int flags) { struct mcs_channel_item *channel; channel = xrdp_channel_get_item(self, channel_id); if (channel == NULL) { g_writeln("xrdp_channel_send - no such channel"); return 1; } s_pop_layer(s, channel_hdr); out_uint32_le(s, total_data_len); /* * According to 2.2.1.3.4.1 Channel Definition Structure (CHANNEL_DEF): * CHANNEL_OPTION_SHOW_PROTOCOL 0x00200000 * The value of this flag MUST be ignored by the server. The * visibility of the Channel PDU Header (section 2.2.6.1.1) is * determined by the CHANNEL_FLAG_SHOW_PROTOCOL * (0x00000010) flag as defined in the flags field (section * 2.2.6.1.1). * * That's flag makes MSTSC crash when using RAIL channel. */ // if (channel->flags & XR_CHANNEL_OPTION_SHOW_PROTOCOL) // { // flags |= CHANNEL_FLAG_SHOW_PROTOCOL; // } out_uint32_le(s, flags); if (xrdp_sec_send(self->sec_layer, s, channel->chanid) != 0) { g_writeln("xrdp_channel_send - failure sending data"); return 1; } return 0; } /*****************************************************************************/ /* returns error */ /* this will inform the callback, whatever it is that some channel data is ready. the default for this is a call to xrdp_wm.c. */ static int xrdp_channel_call_callback(struct xrdp_channel *self, struct stream *s, int channel_id, int total_data_len, int flags) { struct xrdp_session *session; int rv; int size; rv = 0; session = self->sec_layer->rdp_layer->session; if (session != 0) { if (session->callback != 0) { size = (int)(s->end - s->p); /* in xrdp_wm.c */ rv = session->callback(session->id, 0x5555, MAKELONG(channel_id, flags), size, (tbus)(s->p), total_data_len); } else { g_writeln("in xrdp_channel_call_callback, session->callback is nil"); } } else { g_writeln("in xrdp_channel_call_callback, session is nil"); } return rv; } /*****************************************************************************/ /* returns error */ /* This is called from the secure layer to process an incoming non global channel packet. 'chanid' passed in here is the mcs channel id so it MCS_GLOBAL_CHANNEL plus something. */ int xrdp_channel_process(struct xrdp_channel *self, struct stream *s, int chanid) { int length; int flags; int rv; int channel_id; struct mcs_channel_item *channel; /* this assumes that the channels are in order of chanid(mcs channel id) but they should be, see xrdp_sec_process_mcs_data_channels the first channel should be MCS_GLOBAL_CHANNEL + 1, second one should be MCS_GLOBAL_CHANNEL + 2, and so on */ channel_id = (chanid - MCS_GLOBAL_CHANNEL) - 1; channel = xrdp_channel_get_item(self, channel_id); if (channel == NULL) { g_writeln("xrdp_channel_process, channel not found"); return 1; } rv = 0; in_uint32_le(s, length); in_uint32_le(s, flags); rv = xrdp_channel_call_callback(self, s, channel_id, length, flags); return rv; }