Use proper user-initiated disconnect sequence

A correct user initated disconnect sequence should send
a MCS Disconnect Provider Ultimatum PDU defined in T.128
upon a disconnect. This commit adds the implementation
the mentioned PDU and the actual write of the packet.

Signed-off-by: Henrik Andersson <hean01@cendio.com>

5 files changed, 61 insertions, 3 deletions

diff --git a/constants.h b/constants.h
index 753a250..267522b 100644
--- a/constants.h
+++ b/constants.h
@@ -126,6 +126,17 @@ enum MCS_PDU_TYPE
 #define MCS_GLOBAL_CHANNEL	1003
 #define MCS_USERCHANNEL_BASE    1001
 
+/* ITU-T Rec. T.125, Reason enumeration used with Disconnect Provider
+   Ultimatum, see mcs_send_dpu(reason) */
+enum MCS_DPU_REASON
+{
+  RN_DOMAIN_DISCONNECTED = 0,
+  RN_PROVIDER_INITIATED,
+  RN_TOKEN_PURGED,
+  RN_USER_REQUESTED,
+  RN_CHANNEL_PURGED,
+};
+
 /* RDP secure transport constants */
 #define SEC_RANDOM_SIZE		32
 #define SEC_MODULUS_SIZE	64
diff --git a/mcs.c b/mcs.c
index 8ddf1d0..615aa61 100644
--- a/mcs.c
+++ b/mcs.c
@@ -237,6 +237,32 @@ mcs_recv_cjcf(void)
 	return s_check_end(s);
 }
 
+
+/* Send MCS Disconnect provider ultimatum PDU */
+void
+mcs_send_dpu(unsigned short reason)
+{
+	STREAM s, contents;
+
+	logger(Protocol, Debug, "mcs_send_dpu(), reason=%d", reason);
+
+	contents = malloc(sizeof(struct stream));
+	memset(contents, 0, sizeof(struct stream));
+	s_realloc(contents, 6);
+	s_reset(contents);
+	ber_out_integer(contents, reason);	/* Reason */
+	ber_out_sequence(contents, NULL);	/* SEQUENCE OF NonStandradParameters OPTIONAL */
+	s_mark_end(contents);
+
+	s = iso_init(8);
+	ber_out_sequence(s, contents);
+	s_free(contents);
+
+	s_mark_end(s);
+
+	iso_send(s);
+}
+
 /* Initialise an MCS transport data packet */
 STREAM
 mcs_init(int length)
@@ -353,8 +379,9 @@ mcs_connect_finalize(STREAM mcs_data)
 
 /* Disconnect from the MCS layer */
 void
-mcs_disconnect(void)
+mcs_disconnect(int reason)
 {
+	mcs_send_dpu(reason);
 	iso_disconnect();
 }
 
diff --git a/proto.h b/proto.h
index 54ed81b..a5aa2f5 100644
--- a/proto.h
+++ b/proto.h
@@ -99,7 +99,7 @@ STREAM mcs_recv(uint16 * channel, uint8 * rdpver);
 RD_BOOL mcs_connect_start(char *server, char *username, char *domain, char *password,
 			  RD_BOOL reconnect, uint32 * selected_protocol);
 RD_BOOL mcs_connect_finalize(STREAM s);
-void mcs_disconnect(void);
+void mcs_disconnect(int reason);
 void mcs_reset_state(void);
 /* orders.c */
 void process_orders(STREAM s, uint16 num_orders);
diff --git a/secure.c b/secure.c
index f416aba..679f4a0 100644
--- a/secure.c
+++ b/secure.c
@@ -958,7 +958,9 @@ sec_connect(char *server, char *username, char *domain, char *password, RD_BOOL
 void
 sec_disconnect(void)
 {
-	mcs_disconnect();
+	/* Perform a User-initiated disconnect sequence, see
+	   [MS-RDPBCGR] 1.3.1.4 Disconnect Sequences */
+	mcs_disconnect(RN_USER_REQUESTED);
 }
 
 /* reset the state of the sec layer */
diff --git a/tests/mcs_test.c b/tests/mcs_test.c
index 5799602..37d6ff5 100644
--- a/tests/mcs_test.c
+++ b/tests/mcs_test.c
@@ -81,3 +81,21 @@ Ensure(MCS, should_produce_valid_packet_for_McsSendCJrq)
   mcs_send_cjrq(chan_id);
   s_free(s);
 }
+
+/* Test function */
+Ensure(MCS, should_produce_valid_packet_for_McsSendDPU)
+{
+  int reason = 1;
+  struct stream *s;
+  uint8_t content[] = {0x30, 0x06, 0x02, 0x02, 0x00, reason, 0x30, 0x00};
+
+  s = stream_new(8);
+
+  expect(logger);
+  expect(iso_init, will_return(s));
+
+  expect(iso_send, when(stream->data, is_equal_to_contents_of(content, sizeof(content))));
+
+  mcs_send_dpu(reason);
+  s_free(s);
+}