GUACAMOLE-221: Implement guacd support for verifying that client can accept the required instruction.

src/guacd/proc.c

@@ -340,6 +340,9 @@ static void guacd_exec_proc(guacd_proc* proc, const char* protocol) {
         owner = 0;
 
     }
+    
+    /* Enable keep alive on the broadcast socket */
+    guac_socket_require_keep_alive(client->socket);
 
 cleanup_client:
 

src/libguac/client.c

@@ -478,22 +478,39 @@ int guac_client_load_plugin(guac_client* client, const char* protocol) {
 
 }
 
+/**
+ * Callback function which is invoked by guac_client_owner_send_required() to
+ * send the required parameters to the specified user, who is the owner of the
+ * client session.
+ * 
+ * @param user
+ *     The guac_user that will receive the required parameters, who is the owner
+ *     of the client.
+ * 
+ * @param data
+ *     Pointer to a NULL-terminated array of required parameters that will be
+ *     passed on to the owner to continue the connection.
+ * 
+ * @return
+ *     A pointer to an integer containing the return status of the send
+ *     operation.
+ */
+static void* guac_client_owner_send_required_callback(guac_user* user, void* data) {
+    
+    const char** required = (const char **) data;
+    
+    /* Send required parameters to owner. */
+    return (void*) ((intptr_t) guac_protocol_send_required(user->socket, required));
+    
+}
+
 int guac_client_owner_send_required(guac_client* client, const char** required) {
 
-    int retval;
-
-    pthread_rwlock_rdlock(&(client->__users_lock));
-
-    /* Invoke callback with current owner */
-    retval = guac_protocol_send_required(client->__owner->socket, required);
+    /* Don't send required instruction if client does not support it. */
+    if (!guac_client_owner_supports_required(client))
+        return -1;
     
-    /* Flush the socket */
-    guac_socket_flush(client->__owner->socket);
-
-    pthread_rwlock_unlock(&(client->__users_lock));
-
-    /* Return value from sending required */
-    return retval;
+    return (int) ((intptr_t) guac_client_for_owner(client, guac_client_owner_send_required_callback, required));
 
 }
 
@@ -652,6 +669,44 @@ static void* __webp_support_callback(guac_user* user, void* data) {
 }
 #endif
 
+/**
+ * Callback function which is invoked by guac_client_owner_supports_required()
+ * to determine if the owner of a client supports the "required" instruction,
+ * updating the flag to indicate support.
+ * 
+ * @param user
+ *     The guac_user that will be checked for "required" instruction support.
+ * 
+ * @param data
+ *     Pointer to an int containing the status for support of the "required"
+ *     instruction.  This will be 0 if the owner does not support this
+ *     instruction, or 1 if the owner does support it.
+ * 
+ * @return
+ *     Always NULL.
+ */
+static void* guac_owner_supports_required_callback(guac_user* user, void* data) {
+    
+    int* required_supported = (int *) data;
+    
+    /* Check if owner supports required */
+    if (*required_supported)
+        *required_supported = guac_user_supports_required(user);
+    
+    return NULL;
+    
+}
+
+int guac_client_owner_supports_required(guac_client* client) {
+    
+    int required_supported = 1;
+    
+    guac_client_for_owner(client, guac_owner_supports_required_callback, &required_supported);
+    
+    return required_supported;
+    
+}
+
 int guac_client_supports_webp(guac_client* client) {
 
 #ifdef ENABLE_WEBP

src/libguac/guacamole/client.h

@@ -708,6 +708,21 @@ void guac_client_stream_webp(guac_client* client, guac_socket* socket,
         guac_composite_mode mode, const guac_layer* layer, int x, int y,
         cairo_surface_t* surface, int quality, int lossless);
 
+/**
+ * Returns whether the owner of the given client supports the "required"
+ * instruction, returning non-zero if the client owner does support the
+ * instruction, or zero if the owner does not.
+ * 
+ * @param client
+ *     The Guacamole client whose owner should be checked for supporting
+ *     the "required" instruction.
+ * 
+ * @return 
+ *     Non-zero if the owner of the given client supports the "required"
+ *     instruction, zero otherwise.
+ */
+int guac_client_owner_supports_required(guac_client* client);
+
 /**
  * Returns whether all users of the given client support WebP. If any user does
  * not support WebP, or the server cannot encode WebP images, zero is returned.

src/libguac/guacamole/protocol-constants.h

@@ -38,7 +38,7 @@
  * This version is passed by the __guac_protocol_send_args() function from the
  * server to the client during the client/server handshake.
  */
-#define GUACAMOLE_PROTOCOL_VERSION "VERSION_1_1_0"
+#define GUACAMOLE_PROTOCOL_VERSION "VERSION_1_3_0"
 
 /**
  * The maximum number of bytes that should be sent in any one blob instruction

src/libguac/guacamole/protocol-types.h

@@ -20,6 +20,8 @@
 #ifndef _GUAC_PROTOCOL_TYPES_H
 #define _GUAC_PROTOCOL_TYPES_H
 
+#include <stddef.h>
+
 /**
  * Type definitions related to the Guacamole protocol.
  *
@@ -276,5 +278,38 @@ typedef enum guac_line_join_style {
     GUAC_LINE_JOIN_ROUND = 0x2
 } guac_line_join_style;
 
+/**
+ * Track the various protocol versions supported by guacd to help negotiate
+ * features that may not be supported by various versions of the client.
+ */
+typedef enum guac_protocol_version {
+    
+    /**
+     * An unknown version of the Guacamole protocol.
+     */
+    GUAC_PROTOCOL_VERSION_UNKNOWN = 0x000000,
+    
+    /**
+     * Original protocol version 1.0.0, which lacks support for negotiating
+     * parameters and protocol version.
+     */
+    GUAC_PROTOCOL_VERSION_1_0_0 = 0x010000,
+            
+    /**
+     * Protocol version 1.1.0, which includes support for parameter and version
+     * negotiation and for sending timezone information from the client
+     * to the server.
+     */
+    GUAC_PROTOCOL_VERSION_1_1_0 = 0x010100,
+            
+    /**
+     * Protocol version 1.3.0, which supports the "required" instruction,
+     * allowing connections in guacd to request information from the client and
+     * await a response.
+     */
+    GUAC_PROTOCOL_VERSION_1_3_0 = 0x010300
+
+} guac_protocol_version;
+
 #endif
 

src/libguac/guacamole/protocol.h

@@ -1023,5 +1023,32 @@ int guac_protocol_send_name(guac_socket* socket, const char* name);
  */
 int guac_protocol_decode_base64(char* base64);
 
+/**
+ * Given a string representation of a protocol version, search the mapping
+ * to find the matching enum version, or GUAC_PROTOCOL_VERSION_UNKNOWN if no
+ * match is found.
+ * 
+ * @param version_string
+ *     The string representation of the protocol version.
+ * 
+ * @return 
+ *     The enum value of the protocol version, or GUAC_PROTOCOL_VERSION_UNKNOWN
+ *     if no match is found.
+ */
+guac_protocol_version guac_protocol_string_to_version(char* version_string);
+
+/**
+ * Given the enum value of the protocol version, return a pointer to the string
+ * representation of the version, or NULL if the version is unknown.
+ * 
+ * @param version
+ *     The enum value of the protocol version.
+ * 
+ * @return 
+ *     A pointer to the string representation of the protocol version, or NULL
+ *     if the version is unknown.
+ */
+const char* guac_protocol_version_to_string(guac_protocol_version version);
+
 #endif
 

src/libguac/guacamole/socket.h

@@ -136,10 +136,6 @@ void guac_socket_free(guac_socket* socket);
  * to ensure neither side of the socket times out while the socket is open.
  * This ping will take the form of a "nop" instruction.
  *
- * @deprecated
- *     Manually starting the keep alive process on sockets is no longer
- *     necessary, as the sockets enable the "nop" ping by default.
- * 
  * @param socket
  *     The guac_socket to declare as requiring an automatic keep-alive ping.
  */

src/libguac/guacamole/user.h

@@ -95,6 +95,12 @@ struct guac_user_info {
      * is the standard tzdata naming convention.
      */
     const char* timezone;
+    
+    /**
+     * The Guacamole protocol version that the remote system supports, allowing
+     * for feature support to be negotiated between client and server.
+     */
+    guac_protocol_version protocol_version;
 
 };
 
@@ -823,6 +829,17 @@ void guac_user_stream_webp(guac_user* user, guac_socket* socket,
         guac_composite_mode mode, const guac_layer* layer, int x, int y,
         cairo_surface_t* surface, int quality, int lossless);
 
+/**
+ * Returns whether the given user supports the "required" instruction.
+ * 
+ * @param user
+ *     The Guacamole user to check for support of the "required" instruction.
+ * 
+ * @return 
+ *     Non-zero if the user supports the "required" instruction, otherwise zero.
+ */
+int guac_user_supports_required(guac_user* user);
+
 /**
  * Returns whether the given user supports WebP. If the user does not
  * support WebP, or the server cannot encode WebP images, zero is returned.

src/libguac/protocol.c

@@ -23,6 +23,7 @@
 #include "guacamole/layer.h"
 #include "guacamole/object.h"
 #include "guacamole/protocol.h"
+#include "guacamole/protocol-types.h"
 #include "guacamole/socket.h"
 #include "guacamole/stream.h"
 #include "guacamole/unicode.h"
@@ -39,6 +40,34 @@
 #include <string.h>
 #include <sys/types.h>
 
+/**
+ * Structure mapping the enum value of a protocol version to the string
+ * representation of the version.
+ */
+typedef struct guac_protocol_version_mapping {
+    
+    /**
+     * The enum value representing the selected protocol version.
+     */
+    guac_protocol_version version;
+    
+    /**
+     * The string value representing the protocol version.
+     */
+    char* version_string;
+    
+} guac_protocol_version_mapping;
+
+/**
+ * The map of known protocol version enum to the corresponding string value.
+ */
+guac_protocol_version_mapping guac_protocol_version_table[] = {
+    { GUAC_PROTOCOL_VERSION_1_0_0,   "VERSION_1_0_0" },
+    { GUAC_PROTOCOL_VERSION_1_1_0,   "VERSION_1_1_0" },
+    { GUAC_PROTOCOL_VERSION_1_3_0,   "VERSION_1_3_0" },
+    { GUAC_PROTOCOL_VERSION_UNKNOWN, NULL }
+};
+
 /* Output formatting functions */
 
 ssize_t __guac_socket_write_length_string(guac_socket* socket, const char* str) {
@@ -1275,3 +1304,34 @@ int guac_protocol_decode_base64(char* base64) {
 
 }
 
+guac_protocol_version guac_protocol_string_to_version(char* version_string) {
+    
+    guac_protocol_version_mapping* current = guac_protocol_version_table;
+    while (current->version != GUAC_PROTOCOL_VERSION_UNKNOWN) {
+        
+        if (strcmp(current->version_string, version_string) == 0)
+            return current->version;
+        
+        current++;
+        
+    }
+    
+    return GUAC_PROTOCOL_VERSION_UNKNOWN;
+    
+}
+
+const char* guac_protocol_version_to_string(guac_protocol_version version) {
+    
+    guac_protocol_version_mapping* current = guac_protocol_version_table;
+    while (current->version) {
+        
+        if (current->version == version) {
+            return (const char*) current->version_string;
+        }
+        
+    }
+    
+    return NULL;
+    
+}
+

src/libguac/socket.c

@@ -150,10 +150,8 @@ guac_socket* guac_socket_alloc() {
     socket->state = GUAC_SOCKET_OPEN;
     socket->last_write_timestamp = guac_timestamp_current();
 
-    /* keep alive ping by default */
-    socket->__keep_alive_enabled = 1;
-    pthread_create(&(socket->__keep_alive_thread), NULL,
-                __guac_socket_keep_alive_thread, (void*) socket);
+    /* No keep alive ping by default */
+    socket->__keep_alive_enabled = 0;
 
     /* No handlers yet */
     socket->read_handler   = NULL;

src/libguac/user-handshake.c

@@ -344,12 +344,16 @@ int guac_user_handle_connection(guac_user* user, int usec_timeout) {
         guac_client_log(client, GUAC_LOG_INFO, "User \"%s\" joined connection "
                 "\"%s\" (%i users now present)", user->user_id,
                 client->connection_id, client->connected_users);
-        if (strcmp(parser->argv[0],"") != 0)
+        if (strcmp(parser->argv[0],"") != 0) {
             guac_client_log(client, GUAC_LOG_DEBUG, "Client is using protocol "
                     "version \"%s\"", parser->argv[0]);
-        else
+            user->info.protocol_version = guac_protocol_string_to_version(parser->argv[0]);
+        }
+        else {
             guac_client_log(client, GUAC_LOG_DEBUG, "Client has not defined "
                     "its protocol version.");
+            user->info.protocol_version = GUAC_PROTOCOL_VERSION_1_0_0;
+        }
 
         /* Handle user I/O, wait for connection to terminate */
         guac_user_start(parser, user, usec_timeout);

src/libguac/user.c

@@ -316,6 +316,15 @@ void guac_user_stream_webp(guac_user* user, guac_socket* socket,
 
 }
 
+int guac_user_supports_required(guac_user* user) {
+    
+    if (user == NULL)
+        return 0;
+    
+    return (user->info.protocol_version >= GUAC_PROTOCOL_VERSION_1_3_0);
+    
+}
+
 int guac_user_supports_webp(guac_user* user) {
 
 #ifdef ENABLE_WEBP

src/protocols/rdp/rdp.c

@@ -202,7 +202,7 @@ BOOL rdp_freerdp_pre_connect(freerdp* instance) {
 /**
  * Callback invoked by FreeRDP when authentication is required but a username
  * and password has not already been given. In the case of Guacamole, this
- * function always succeeds but does not populate the usename or password. The
+ * function always succeeds but does not populate the username or password. The
  * username/password must be given within the connection parameters.
  *
  * @param instance
@@ -232,6 +232,11 @@ static BOOL rdp_freerdp_authenticate(freerdp* instance, char** username,
     char* params[4] = {};
     int i = 0;
     
+    /* If the client does not support the "required" instruction, just
+        exit. */
+    if (!guac_client_owner_supports_required(client))
+        return TRUE;
+    
     if (settings->username == NULL) {
         params[i] = GUAC_RDP_PARAMETER_NAME_USERNAME;
         rdp_client->rdp_credential_flags |= GUAC_RDP_CRED_FLAG_USERNAME;
@@ -257,7 +262,7 @@ static BOOL rdp_freerdp_authenticate(freerdp* instance, char** username,
         /* Lock the client thread. */
         pthread_mutex_lock(&(rdp_client->rdp_credential_lock));
         
-        /* Send require parameters to the owner. */
+        /* Send required parameters to the owner. */
         guac_client_owner_send_required(client, (const char**) params);
         
         /* Wait for condition. */

src/protocols/ssh/ssh.c

@@ -74,6 +74,10 @@ static void guac_ssh_get_credential(guac_client *client, char* cred_name) {
 
     guac_ssh_client* ssh_client = (guac_ssh_client*) client->data;
     
+    /* If the client does not support the "required" instruction, just return. */
+    if (!guac_client_owner_supports_required(client))
+        return;
+    
     /* Lock the terminal thread while prompting for the credential. */
     pthread_mutex_lock(&(ssh_client->term_channel_lock));
     

src/protocols/vnc/auth.c

@@ -36,6 +36,11 @@ char* guac_vnc_get_password(rfbClient* client) {
     guac_vnc_client* vnc_client = ((guac_vnc_client*) gc->data);
     guac_vnc_settings* settings = vnc_client->settings;
     
+    /* If the client does not support the "required" instruction, just return
+        the configuration data. */
+    if (!guac_client_owner_supports_required(gc))
+        return ((guac_vnc_client*) gc->data)->settings->password;
+    
     /* If password isn't around, prompt for it. */
     if (settings->password == NULL || strcmp(settings->password, "") == 0) {
         /* Lock the thread. */
@@ -64,10 +69,19 @@ rfbCredential* guac_vnc_get_credentials(rfbClient* client, int credentialType) {
     guac_client* gc = rfbClientGetClientData(client, GUAC_VNC_CLIENT_KEY);
     guac_vnc_client* vnc_client = ((guac_vnc_client*) gc->data);
     guac_vnc_settings* settings = vnc_client->settings;
-
+    
     /* Handle request for Username/Password credentials */
     if (credentialType == rfbCredentialTypeUser) {
         rfbCredential *creds = malloc(sizeof(rfbCredential));
+        
+        /* If the client does not support the "required" instruction, just return
+           the parameters already configured. */
+        if (!guac_client_owner_supports_required(gc)) {
+            creds->userCredential.username = settings->username;
+            creds->userCredential.password = settings->password;
+            return creds;
+        }
+        
         char* params[2] = {NULL};
         int i = 0;