add option to set interface state up/down, not working yet (returns "Object busy" from netlink)

interface.cpp

@@ -39,6 +39,84 @@ m_index(-1)
   m_index = Utils::interfaceIndex(interface);
 }
 
+bool Interface::setLinkUp(QString &error) {
+  struct rtnl_link *link, *link_orig = NULL;
+  struct nl_sock *sock = NULL;
+  QByteArray interfaceArray = m_interface.toLatin1();
+  const char *interface = interfaceArray.constData();
+
+  if((sock = Utils::connect())) {
+    rtnl_link_get_kernel(sock, 0, interface, &link_orig);
+
+    if(rtnl_link_get_kernel(sock, 0, interface, &link) < 0) {
+      std::cerr << "error looking up interface" << std::endl;
+      nl_socket_free(sock);
+    }else{
+      unsigned int flags = rtnl_link_get_flags(link);
+      int err = 0;
+
+      flags |= IFF_UP;
+
+      rtnl_link_set_flags(link, flags);
+
+      if((err = rtnl_link_change(sock, link_orig, link, 0)) < 0) {
+        error = nl_geterror(err);
+        rtnl_link_put(link);
+        rtnl_link_put(link_orig);
+        nl_socket_free(sock);
+        return false;
+      }
+
+      rtnl_link_put(link);
+      rtnl_link_put(link_orig);
+      nl_socket_free(sock);
+
+      return true;
+    }
+  }
+
+  return false;
+}
+
+bool Interface::setLinkDown(QString &error) {
+  struct rtnl_link *link, *link_orig = NULL;
+  struct nl_sock *sock = NULL;
+  QByteArray interfaceArray = m_interface.toLatin1();
+  const char *interface = interfaceArray.constData();
+
+  if((sock = Utils::connect())) {
+    rtnl_link_get_kernel(sock, 0, interface, &link_orig);
+
+    if(rtnl_link_get_kernel(sock, 0, interface, &link) < 0) {
+      std::cerr << "error looking up interface" << std::endl;
+      nl_socket_free(sock);
+    }else{
+      unsigned int flags = rtnl_link_get_flags(link);
+      int err = 0;
+
+      flags &= ~IFF_UP;
+
+      rtnl_link_set_flags(link, flags);
+
+      if((err = rtnl_link_change(sock, link_orig, link, 0)) < 0) {
+        error = nl_geterror(err);
+        rtnl_link_put(link);
+        rtnl_link_put(link_orig);
+        nl_socket_free(sock);
+        return false;
+      }
+
+      rtnl_link_put(link);
+      rtnl_link_put(link_orig);
+      nl_socket_free(sock);
+
+      return true;
+    }
+  }
+
+  return false;
+}
+
 /*!
     Add an IP address to the interface using the CIDR notation, e.g. 192.168.1.1/24. Requires that the CAP_NET_ADMIN capability be set on the application binary, or run as root (\a not \a recommended). Returns 0 on success, 1 on error.
 */
@@ -214,6 +292,43 @@ int Interface::deleteAddress(QString addressStr) const {
   return 0;
 }
 
+/*!
+    Returns true if the interface is administratively up, otherwise false if it is administratively down or if there was an error retrieving the status information. If there was an error, *ok will be set to false, otherwise it will be true.
+*/
+bool Interface::hasAdminLink(bool *ok) {
+  struct rtnl_link *link = NULL;
+  struct nl_sock *sock = NULL;
+  QByteArray interfaceArray = m_interface.toLatin1();
+  const char *interface = interfaceArray.constData();
+  bool carrier = false;
+
+  if((sock = Utils::connect())) {
+    if(rtnl_link_get_kernel(sock, 0, interface, &link) < 0) {
+      std::cerr << "error looking up interface" << std::endl;
+      nl_socket_free(sock);
+    }else{
+      unsigned int flags = rtnl_link_get_flags(link);
+
+      carrier = (flags & IFF_UP) == IFF_UP;
+
+      rtnl_link_put(link);
+      nl_socket_free(sock);
+
+      if(ok != NULL) {
+        *ok = true;
+      }
+
+      return carrier;
+    }
+  }
+
+  if(ok != NULL) {
+    *ok = false;
+  }
+
+  return false;
+}
+
 /*!
     Returns true if the interface is up and running (link-layer is up), and false if the link/interface is down, or if there was an error retrieving the status information. If there was an error, *ok will be set to false, otherwise it will be true.
 */

interface.h

@@ -12,6 +12,9 @@ public:
   static QStringList list();
   QStringList addresses() const;
   bool hasCarrier(bool *ok = 0);
+  bool hasAdminLink(bool *ok = 0);
+  bool setLinkUp(QString &error);
+  bool setLinkDown(QString &error);
   int addAddress(QString address) const;
   int deleteAddress(QString address) const;
   const QString& name() const;

tui/menu.cpp

@@ -265,6 +265,15 @@ void Menu::interfaceMenu(WINDOW *window) {
     interface = QString::number(count) + ". " + interface;
     QByteArray interfaceArray = interface.toLatin1();
     const char *interfaceStr = interfaceArray.constData();
+    Interface interfaceObj(orig);
+
+    if(interfaceObj.hasCarrier()) {
+      green(window);
+    }else if(interfaceObj.hasAdminLink()) {
+      cyan(window);
+    }else{
+      red(window);
+    }
 
     mvwaddstr(window, y, 2, interfaceStr);
 
@@ -619,9 +628,11 @@ void Menu::interfaceSelect(WINDOW *window, QString interface) {
   magenta(window);
   mvwaddstr(window, y + 3, 2, "a. Add IP address");
   mvwaddstr(window, y + 4, 2, "d. Delete IP address");
-  mvwaddstr(window, y + 5, 2, "q. Quit");
+  mvwaddstr(window, y + 5, 2, "+. Set link up");
+  mvwaddstr(window, y + 6, 2, "-. Set link down");
+  mvwaddstr(window, y + 7, 2, "q. Quit");
 
-  mvwaddstr(window, y + 7, 2, "Enter selection: ");
+  mvwaddstr(window, y + 9, 2, "Enter selection: ");
   wrefresh(window);
 
   char c = getch();
@@ -633,7 +644,7 @@ void Menu::interfaceSelect(WINDOW *window, QString interface) {
       // no-op, just quit
     }else if(c == 'a') {
       wdeleteln(window);
-      mvwaddstr(window, y + 7, 2, "Enter IP address to add: ");
+      mvwaddstr(window, y + 9, 2, "Enter IP address to add: ");
       wrefresh(window);
 
       char ipToAdd[19] = {0};
@@ -659,7 +670,7 @@ void Menu::interfaceSelect(WINDOW *window, QString interface) {
       QByteArray arr = confirm.toLatin1();
       const char *confirmStr = arr.constData();
 
-      mvwaddstr(window, y + 7, 2, confirmStr);
+      mvwaddstr(window, y + 9, 2, confirmStr);
       wrefresh(window);
 
       c = getch();
@@ -677,7 +688,7 @@ void Menu::interfaceSelect(WINDOW *window, QString interface) {
       }
     }else if(c == 'd') {
       wdeleteln(window);
-      mvwaddstr(window, y + 7, 2, "Enter number of IP address to delete: ");
+      mvwaddstr(window, y + 9, 2, "Enter number of IP address to delete: ");
       wrefresh(window);
       char ipToDelete = getch();
 
@@ -700,7 +711,7 @@ void Menu::interfaceSelect(WINDOW *window, QString interface) {
       QByteArray arr = confirm.toLatin1();
       const char *confirmStr = arr.constData();
 
-      mvwaddstr(window, y + 7, 2, confirmStr);
+      mvwaddstr(window, y + 9, 2, confirmStr);
       wrefresh(window);
 
       c = getch();
@@ -716,6 +727,34 @@ void Menu::interfaceSelect(WINDOW *window, QString interface) {
       }else{
         interfaceSelect(window, interface);
       }
+    }else if(c == '+') {
+      QString error;
+
+      if(!obj.setLinkUp(error)) {
+        QString err = QString("Could not change link state: ") + error;
+        QByteArray arr = err.toLatin1();
+        const char *errorString = arr.constData();
+
+        msgbox(errorString);
+      }else{
+        msgbox("Link state set to UP.");
+      }
+
+      interfaceSelect(window, interface);
+    }else if(c == '-') {
+      QString error;
+
+      if(!obj.setLinkDown(error)) {
+        QString err = QString("Could not change link state: ") + error;
+        QByteArray arr = err.toLatin1();
+        const char *errorString = arr.constData();
+
+        msgbox(errorString);
+      }else{
+        msgbox("Link state set to DOWN.");
+      }
+
+      interfaceSelect(window, interface);
     }else{
       interfaceSelect(window, interface);
     }