GUACAMOLE-203: Correct implementation of SSH keepalive option for SFTP connections across all protocols.

src/protocols/rdp/rdp.c

@@ -977,7 +977,7 @@ void* guac_rdp_client_thread(void* data) {
         /* Attempt SSH connection */
         rdp_client->sftp_session =
             guac_common_ssh_create_session(client, settings->sftp_hostname,
-                    settings->sftp_port, rdp_client->sftp_user, rdp_client->sftp_keepalive);
+                    settings->sftp_port, rdp_client->sftp_user, settings->sftp_keepalive);
 
         /* Fail if SSH connection does not succeed */
         if (rdp_client->sftp_session == NULL) {

src/protocols/rdp/rdp.h

@@ -141,11 +141,6 @@ typedef struct guac_rdp_client {
      * An SFTP-based filesystem.
      */
     guac_common_ssh_sftp_filesystem* sftp_filesystem;
-
-    /**
-     * A keepalive interval for SFTP connections.
-     */
-    int sftp_keepalive;
 #endif
 
     /**

src/protocols/rdp/rdp_settings.c

@@ -84,6 +84,7 @@ const char* GUAC_RDP_CLIENT_ARGS[] = {
     "sftp-private-key",
     "sftp-passphrase",
     "sftp-directory",
+    "sftp-keepalive",
 #endif
 
     "recording-path",
@@ -366,6 +367,13 @@ enum RDP_ARGS_IDX {
      */
     IDX_SFTP_DIRECTORY,
 
+    /**
+     * The interval at which SSH keepalive messages are sent to the server for
+     * SFTP connections.  The default is 0 (disabling keepalives), and a value
+     * of 1 is automatically increased to 2 by libssh2 to avoid busy loop corner
+     * cases.
+     */
+    IDX_SFTP_KEEPALIVE,
 #endif
 
     /**
@@ -775,6 +783,14 @@ guac_rdp_settings* guac_rdp_parse_args(guac_user* user,
     settings->sftp_directory =
         guac_user_parse_args_string(user, GUAC_RDP_CLIENT_ARGS, argv,
                 IDX_SFTP_DIRECTORY, NULL);
+
+    /* Default keepalive value */
+    settings->sftp_keepalive =
+        guac_user_parse_args_int(user, GUAC_RDP_CLIENT_ARGS, argv,
+                IDX_SFTP_KEEPALIVE, 0);
+    if (settings->sftp_keepalive == 1)
+        guac_user_log(user, GUAC_LOG_WARNING, "The minimum allowed "
+                "value for keepalives by libssh2 is 2 seconds.");
 #endif
 
     /* Read recording path */

src/protocols/rdp/rdp_settings.h

@@ -359,6 +359,14 @@ typedef struct guac_rdp_settings {
      * the destination directory is otherwise ambiguous).
      */
     char* sftp_directory;
+
+    /**
+     * The interval at which SSH keepalive messages are sent to the server for
+     * SFTP connections.  The default is 0 (disabling keepalives), and a value
+     * of 1 is automatically increased to 2 by libssh2 to avoid busy loop corner
+     * cases.
+     */
+    int sftp_keepalive;
 #endif
 
     /**

src/protocols/vnc/settings.c

@@ -66,6 +66,7 @@ const char* GUAC_VNC_CLIENT_ARGS[] = {
     "sftp-private-key",
     "sftp-passphrase",
     "sftp-directory",
+    "sftp-keepalive",
 #endif
 
     "recording-path",
@@ -227,6 +228,14 @@ enum VNC_ARGS_IDX {
      * the destination directory is otherwise ambiguous).
      */
     IDX_SFTP_DIRECTORY,
+
+    /**
+     * The interval at which SSH keepalive messages are sent to the server for
+     * SFTP connections.  The default is 0 (disabling keepalives), and a value
+     * of 1 is automatically increased to 2 by libssh2 to avoid busy loop corner
+     * cases.
+     */
+    IDX_SFTP_KEEPALIVE,
 #endif
 
     /**
@@ -395,6 +404,14 @@ guac_vnc_settings* guac_vnc_parse_args(guac_user* user,
     settings->sftp_directory =
         guac_user_parse_args_string(user, GUAC_VNC_CLIENT_ARGS, argv,
                 IDX_SFTP_DIRECTORY, NULL);
+
+    /* Default keepalive value */
+    settings->sftp_keepalive =
+        guac_user_parse_args_int(user, GUAC_VNC_CLIENT_ARGS, argv,
+                IDX_SFTP_KEEPALIVE, 0);
+    if (settings->sftp_keepalive == 1)
+        guac_user_log(user, GUAC_LOG_WARNING, "The minimum allowed "
+                "value for keepalives by libssh2 is 2 seconds.");
 #endif
 
     /* Read recording path */

src/protocols/vnc/settings.h

@@ -173,6 +173,14 @@ typedef struct guac_vnc_settings {
      * the destination directory is otherwise ambiguous).
      */
     char* sftp_directory;
+
+    /**
+     * The interval at which SSH keepalive messages are sent to the server for
+     * SFTP connections.  The default is 0 (disabling keepalives), and a value
+     * of 1 is automatically increased to 2 by libssh2 to avoid busy loop corner
+     * cases.
+     */
+    int sftp_keepalive;
 #endif
 
     /**

src/protocols/vnc/vnc.c

@@ -261,7 +261,7 @@ void* guac_vnc_client_thread(void* data) {
         /* Attempt SSH connection */
         vnc_client->sftp_session =
             guac_common_ssh_create_session(client, settings->sftp_hostname,
-                    settings->sftp_port, vnc_client->sftp_user, vnc_client->sftp_keepalive);
+                    settings->sftp_port, vnc_client->sftp_user, settings->sftp_keepalive);
 
         /* Fail if SSH connection does not succeed */
         if (vnc_client->sftp_session == NULL) {

src/protocols/vnc/vnc.h

@@ -108,11 +108,6 @@ typedef struct guac_vnc_client {
      * An SFTP-based filesystem.
      */
     guac_common_ssh_sftp_filesystem* sftp_filesystem;
-
-    /**
-     * The interval at which to send SSH keepalive messages for SFTP.
-     */
-    int sftp_keepalive;
 #endif
 
     /**