GUACAMOLE-600: Add support for setting SSH and SFTP timeouts.

src/common-ssh/common-ssh/ssh.h

@@ -114,6 +114,10 @@ void guac_common_ssh_uninit();
  *
  * @param user
  *     The user to authenticate as, once connected.
+ *
+ * @param timeout
+ *     The number of seconds to attempt to connect to the SSH server before
+ *     timing out.
  * 
  * @param keepalive
  *     How frequently the connection should send keepalive packets, in
@@ -138,7 +142,7 @@ void guac_common_ssh_uninit();
  */
 guac_common_ssh_session* guac_common_ssh_create_session(guac_client* client,
         const char* hostname, const char* port, guac_common_ssh_user* user,
-        int keepalive, const char* host_key,
+        int timeout, int keepalive, const char* host_key,
         guac_ssh_credential_handler* credential_handler);
 
 /**

src/common-ssh/ssh.c

@@ -33,6 +33,7 @@
 #include <openssl/ssl.h>
 
 #include <errno.h>
+#include <fcntl.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <pthread.h>
@@ -40,6 +41,7 @@
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/select.h>
 #include <sys/socket.h>
 #include <unistd.h>
 
@@ -405,7 +407,7 @@ static int guac_common_ssh_authenticate(guac_common_ssh_session* common_session)
 
 guac_common_ssh_session* guac_common_ssh_create_session(guac_client* client,
         const char* hostname, const char* port, guac_common_ssh_user* user,
-        int keepalive, const char* host_key,
+        int timeout, int keepalive, const char* host_key,
         guac_ssh_credential_handler* credential_handler) {
 
     int retval;
@@ -453,17 +455,39 @@ guac_common_ssh_session* guac_common_ssh_create_session(guac_client* client,
             return NULL;
         }
 
-        /* Connect */
+        /* Set socket to non-blocking */
-        if (connect(fd, current_address->ai_addr,
+        fcntl(fd, F_SETFL, O_NONBLOCK);
-                        current_address->ai_addrlen) == 0) {
+        
+        /* Set up timeout. */
+        fd_set fdset;
+        FD_ZERO(&fdset);
+        FD_SET(fd, &fdset);
 
+        struct timeval tv;
+        tv.tv_sec = timeout;             /* 10 second timeout */
+        tv.tv_usec = 0;
+
+        /* Connect and wait for timeout */
+        connect(fd, current_address->ai_addr, current_address->ai_addrlen);
+        
+        retval = select(fd + 1, NULL, &fdset, NULL, &tv);
+
+        /* Timeout has occured - log the failure and move to the next address. */
+        if (retval == 0) {
+            guac_client_log(client, GUAC_LOG_DEBUG,
+                    "Timeout connecting to host %s, port %s",
+                    connected_address, connected_port);
+            continue;
+        }
+
+        /* Connection is successful - log it and break the loop. */
+        else if (retval > 0) {
             guac_client_log(client, GUAC_LOG_DEBUG,
                     "Successfully connected to host %s, port %s",
                     connected_address, connected_port);
 
             /* Done if successful connect */
             break;
-
         }
 
         /* Otherwise log information regarding bind failure */

src/protocols/rdp/rdp.c

@@ -776,8 +776,8 @@ 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, settings->sftp_server_alive_interval,
+                    settings->sftp_port, rdp_client->sftp_user, settings->sftp_timeout,
-                    settings->sftp_host_key, NULL);
+                    settings->sftp_server_alive_interval, settings->sftp_host_key, NULL);
 
         /* Fail if SSH connection does not succeed */
         if (rdp_client->sftp_session == NULL) {

src/protocols/rdp/settings.c

@@ -101,6 +101,7 @@ const char* GUAC_RDP_CLIENT_ARGS[] = {
     "sftp-hostname",
     "sftp-host-key",
     "sftp-port",
+    "sftp-timeout",
     "sftp-username",
     "sftp-password",
     "sftp-private-key",
@@ -435,6 +436,12 @@ enum RDP_ARGS_IDX {
      */
     IDX_SFTP_PORT,
 
+    /**
+     * The number of seconds to attempt to connect to the SSH server before
+     * timing out.
+     */
+    IDX_SFTP_TIMEOUT,
+
     /**
      * The username to provide when authenticating with the SSH server for
      * SFTP. If blank, the username provided for the RDP user will be used.
@@ -1051,6 +1058,11 @@ guac_rdp_settings* guac_rdp_parse_args(guac_user* user,
         guac_user_parse_args_string(user, GUAC_RDP_CLIENT_ARGS, argv,
                 IDX_SFTP_PORT, "22");
 
+    /* SFTP timeout */
+    settings->sftp_timeout =
+        guac_user_parse_args_int(user, GUAC_RDP_CLIENT_ARGS, argv,
+                IDX_SFTP_TIMEOUT, RDP_DEFAULT_SFTP_TIMEOUT);
+
     /* Username for SSH/SFTP authentication */
     settings->sftp_username =
         guac_user_parse_args_string(user, GUAC_RDP_CLIENT_ARGS, argv,

src/protocols/rdp/settings.h

@@ -38,6 +38,11 @@
  */
 #define RDP_DEFAULT_PORT 3389
 
+/**
+ * The default SFTP connection timeout, in seconds.
+ */
+#define RDP_DEFAULT_SFTP_TIMEOUT 10
+
 /**
  * The default RDP port used by Hyper-V "VMConnect".
  */
@@ -440,6 +445,12 @@ typedef struct guac_rdp_settings {
      */
     char* sftp_port;
 
+    /**
+     * The number of seconds to attempt to connect to the SSH server before
+     * timing out.
+     */
+    int sftp_timeout;
+
     /**
      * The username to provide when authenticating with the SSH server for
      * SFTP.

src/protocols/ssh/settings.c

@@ -37,6 +37,7 @@ const char* GUAC_SSH_CLIENT_ARGS[] = {
     "hostname",
     "host-key",
     "port",
+    "timeout",
     "username",
     "password",
     GUAC_SSH_ARGV_FONT_NAME,
@@ -95,6 +96,11 @@ enum SSH_ARGS_IDX {
      */
     IDX_PORT,
 
+    /**
+     * The timeout of the connection attempt, in seconds. Optional.
+     */
+    IDX_TIMEOUT,
+
     /**
      * The name of the user to login as. Optional.
      */
@@ -429,6 +435,11 @@ guac_ssh_settings* guac_ssh_parse_args(guac_user* user,
         guac_user_parse_args_string(user, GUAC_SSH_CLIENT_ARGS, argv,
                 IDX_PORT, GUAC_SSH_DEFAULT_PORT);
 
+    /* Parse the timeout value. */
+    settings->timeout =
+        guac_user_parse_args_int(user, GUAC_SSH_CLIENT_ARGS, argv,
+                IDX_TIMEOUT, GUAC_SSH_DEFAULT_TIMEOUT);
+
     /* Read-only mode */
     settings->read_only =
         guac_user_parse_args_boolean(user, GUAC_SSH_CLIENT_ARGS, argv,

src/protocols/ssh/settings.h

@@ -32,6 +32,12 @@
  */
 #define GUAC_SSH_DEFAULT_PORT "22"
 
+/**
+ * The default number of seconds to attempt a connection to the SSH/SFTP
+ * server before giving up.
+ */
+#define GUAC_SSH_DEFAULT_TIMEOUT 10
+
 /**
  * The filename to use for the typescript, if not specified.
  */
@@ -69,6 +75,12 @@ typedef struct guac_ssh_settings {
      */
     char* port;
 
+    /**
+     * The number of seconds to attempt to connect to the SSH server before
+     * timing out.
+     */
+    int timeout;
+
     /**
      * The name of the user to login as, if any. If no username is specified,
      * this will be NULL.

src/protocols/ssh/ssh.c

@@ -288,7 +288,8 @@ void* ssh_client_thread(void* data) {
 
     /* Open SSH session */
     ssh_client->session = guac_common_ssh_create_session(client,
-            settings->hostname, settings->port, ssh_client->user, settings->server_alive_interval,
+            settings->hostname, settings->port, ssh_client->user,
+            settings->timeout, settings->server_alive_interval,
             settings->host_key, guac_ssh_get_credential);
     if (ssh_client->session == NULL) {
         /* Already aborted within guac_common_ssh_create_session() */
@@ -340,8 +341,8 @@ void* ssh_client_thread(void* data) {
         guac_client_log(client, GUAC_LOG_DEBUG, "Reconnecting for SFTP...");
         ssh_client->sftp_session =
             guac_common_ssh_create_session(client, settings->hostname,
-                    settings->port, ssh_client->user, settings->server_alive_interval,
+                    settings->port, ssh_client->user, settings->timeout,
-                    settings->host_key, NULL);
+                    settings->server_alive_interval, settings->host_key, NULL);
         if (ssh_client->sftp_session == NULL) {
             /* Already aborted within guac_common_ssh_create_session() */
             return NULL;

src/protocols/vnc/settings.c

@@ -66,6 +66,7 @@ const char* GUAC_VNC_CLIENT_ARGS[] = {
     "sftp-hostname",
     "sftp-host-key",
     "sftp-port",
+    "sftp-timeout",
     "sftp-username",
     "sftp-password",
     "sftp-private-key",
@@ -228,6 +229,12 @@ enum VNC_ARGS_IDX {
      */
     IDX_SFTP_PORT,
 
+    /**
+     * The number of seconds to attempt to connect to the SFTP server before
+     * timing out.
+     */
+    IDX_SFTP_TIMEOUT,
+
     /**
      * The username to provide when authenticating with the SSH server for
      * SFTP.
@@ -519,6 +526,11 @@ guac_vnc_settings* guac_vnc_parse_args(guac_user* user,
         guac_user_parse_args_string(user, GUAC_VNC_CLIENT_ARGS, argv,
                 IDX_SFTP_PORT, "22");
 
+    /* SFTP connection timeout */
+    settings->sftp_timeout =
+        guac_user_parse_args_int(user, GUAC_VNC_CLIENT_ARGS, argv,
+                IDX_SFTP_TIMEOUT, GUAC_VNC_DEFAULT_SFTP_TIMEOUT);
+
     /* Username for SSH/SFTP authentication */
     settings->sftp_username =
         guac_user_parse_args_string(user, GUAC_VNC_CLIENT_ARGS, argv,

src/protocols/vnc/settings.h

@@ -30,6 +30,11 @@
  */
 #define GUAC_VNC_DEFAULT_RECORDING_NAME "recording"
 
+/**
+ * The default number of seconds to attempt to connect to the SFTP server.
+ */
+#define GUAC_VNC_DEFAULT_SFTP_TIMEOUT 10
+
 /**
  * VNC-specific client data.
  */
@@ -173,6 +178,11 @@ typedef struct guac_vnc_settings {
      */
     char* sftp_port;
 
+    /**
+     * The number of seconds to attempt to connect to the SFTP server.
+     */
+    int sftp_timeout;
+
     /**
      * The username to provide when authenticating with the SSH server for
      * SFTP.

src/protocols/vnc/vnc.c

@@ -376,8 +376,8 @@ 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, settings->sftp_server_alive_interval,
+                    settings->sftp_port, vnc_client->sftp_user, settings->sftp_timeout,
-                    settings->sftp_host_key, NULL);
+                    settings->sftp_server_alive_interval, settings->sftp_host_key, NULL);
 
         /* Fail if SSH connection does not succeed */
         if (vnc_client->sftp_session == NULL) {