app/src/main/java/com/stoutner/privacybrowser/dialogs/SslCertificateErrorDialog.kt

   1 /*
   2  * Copyright © 2016-2021 Soren Stoutner <soren@stoutner.com>.
   3  *
   4  * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
   5  *
   6  * Privacy Browser is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * Privacy Browser is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with Privacy Browser.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 package com.stoutner.privacybrowser.dialogs
  21
  22 import android.annotation.SuppressLint
  23 import android.app.Activity
  24 import android.app.Dialog
  25 import android.content.DialogInterface
  26 import android.content.res.Configuration
  27 import android.net.Uri
  28 import android.net.http.SslError
  29 import android.os.AsyncTask
  30 import android.os.Bundle
  31 import android.text.SpannableStringBuilder
  32 import android.text.Spanned
  33 import android.text.style.ForegroundColorSpan
  34 import android.view.WindowManager
  35 import android.widget.TextView
  36
  37 import androidx.appcompat.app.AlertDialog
  38 import androidx.fragment.app.DialogFragment
  39 import androidx.preference.PreferenceManager
  40
  41 import com.stoutner.privacybrowser.R
  42 import com.stoutner.privacybrowser.activities.MainWebViewActivity
  43 import com.stoutner.privacybrowser.views.NestedScrollWebView
  44
  45 import java.lang.ref.WeakReference
  46 import java.net.InetAddress
  47 import java.net.UnknownHostException
  48 import java.text.DateFormat
  49
  50 // Define the class constants.
  51 private const val PRIMARY_ERROR_INT = "primary_error_int"
  52 private const val URL_WITH_ERRORS = "url_with_errors"
  53 private const val ISSUED_TO_CNAME = "issued_to_cname"
  54 private const val ISSUED_TO_ONAME = "issued_to_oname"
  55 private const val ISSUED_TO_UNAME = "issued_to_uname"
  56 private const val ISSUED_BY_CNAME = "issued_by_cname"
  57 private const val ISSUED_BY_ONAME = "issued_by_oname"
  58 private const val ISSUED_BY_UNAME = "issued_by_uname"
  59 private const val START_DATE = "start_date"
  60 private const val END_DATE = "end_date"
  61 private const val WEBVIEW_FRAGMENT_ID = "webview_fragment_id"
  62
  63 class SslCertificateErrorDialog : DialogFragment() {
  64     companion object {
  65         // `@JvmStatic` will no longer be required once all the code has transitioned to Kotlin.
  66         @JvmStatic
  67         fun displayDialog(sslError: SslError, webViewFragmentId: Long): SslCertificateErrorDialog {
  68             // Get the various components of the SSL error message.
  69             val primaryErrorInt = sslError.primaryError
  70             val urlWithErrors = sslError.url
  71             val sslCertificate = sslError.certificate
  72             val issuedToCName = sslCertificate.issuedTo.cName
  73             val issuedToOName = sslCertificate.issuedTo.oName
  74             val issuedToUName = sslCertificate.issuedTo.uName
  75             val issuedByCName = sslCertificate.issuedBy.cName
  76             val issuedByOName = sslCertificate.issuedBy.oName
  77             val issuedByUName = sslCertificate.issuedBy.uName
  78             val startDate = sslCertificate.validNotBeforeDate
  79             val endDate = sslCertificate.validNotAfterDate
  80
  81             // Create an arguments bundle.
  82             val argumentsBundle = Bundle()
  83
  84             // Store the SSL error message components in the bundle.
  85             argumentsBundle.putInt(PRIMARY_ERROR_INT, primaryErrorInt)
  86             argumentsBundle.putString(URL_WITH_ERRORS, urlWithErrors)
  87             argumentsBundle.putString(ISSUED_TO_CNAME, issuedToCName)
  88             argumentsBundle.putString(ISSUED_TO_ONAME, issuedToOName)
  89             argumentsBundle.putString(ISSUED_TO_UNAME, issuedToUName)
  90             argumentsBundle.putString(ISSUED_BY_CNAME, issuedByCName)
  91             argumentsBundle.putString(ISSUED_BY_ONAME, issuedByOName)
  92             argumentsBundle.putString(ISSUED_BY_UNAME, issuedByUName)
  93             argumentsBundle.putString(START_DATE, DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.LONG).format(startDate))
  94             argumentsBundle.putString(END_DATE, DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.LONG).format(endDate))
  95             argumentsBundle.putLong(WEBVIEW_FRAGMENT_ID, webViewFragmentId)
  96
  97             // Create a new instance of the SSL certificate error dialog.
  98             val thisSslCertificateErrorDialog = SslCertificateErrorDialog()
  99
 100             // Add the arguments bundle to the new dialog.
 101             thisSslCertificateErrorDialog.arguments = argumentsBundle
 102
 103             // Return the new dialog.
 104             return thisSslCertificateErrorDialog
 105         }
 106     }
 107
 108     // `@SuppressLint("InflateParams")` removes the warning about using `null` as the parent view group when inflating the alert dialog.
 109     @SuppressLint("InflateParams")
 110     override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
 111         // Get the variables from the bundle.
 112         val primaryErrorInt = requireArguments().getInt(PRIMARY_ERROR_INT)
 113         val urlWithErrors = requireArguments().getString(URL_WITH_ERRORS)
 114         val issuedToCName = requireArguments().getString(ISSUED_TO_CNAME)
 115         val issuedToOName = requireArguments().getString(ISSUED_TO_ONAME)
 116         val issuedToUName = requireArguments().getString(ISSUED_TO_UNAME)
 117         val issuedByCName = requireArguments().getString(ISSUED_BY_CNAME)
 118         val issuedByOName = requireArguments().getString(ISSUED_BY_ONAME)
 119         val issuedByUName = requireArguments().getString(ISSUED_BY_UNAME)
 120         val startDate = requireArguments().getString(START_DATE)
 121         val endDate = requireArguments().getString(END_DATE)
 122         val webViewFragmentId = requireArguments().getLong(WEBVIEW_FRAGMENT_ID)
 123
 124         // Get the current position of this WebView fragment.
 125         val webViewPosition = MainWebViewActivity.webViewPagerAdapter.getPositionForId(webViewFragmentId)
 126
 127         // Get the WebView tab fragment.
 128         val webViewTabFragment = MainWebViewActivity.webViewPagerAdapter.getPageFragment(webViewPosition)
 129
 130         // Get the fragment view.
 131         val fragmentView = webViewTabFragment.requireView()
 132
 133         // Get a handle for the current WebView.
 134         val nestedScrollWebView: NestedScrollWebView = fragmentView.findViewById(R.id.nestedscroll_webview)
 135
 136         // Get a handle for the SSL error handler.
 137         val sslErrorHandler = nestedScrollWebView.sslErrorHandler
 138
 139         // Use an alert dialog builder to create the alert dialog.
 140         val dialogBuilder = AlertDialog.Builder(requireContext(), R.style.PrivacyBrowserAlertDialog)
 141
 142         // Get the current theme status.
 143         val currentThemeStatus = resources.configuration.uiMode and Configuration.UI_MODE_NIGHT_MASK
 144
 145         // Set the icon according to the theme.
 146         if (currentThemeStatus == Configuration.UI_MODE_NIGHT_NO) {
 147             dialogBuilder.setIcon(R.drawable.ssl_certificate_enabled_day)
 148         } else {
 149             dialogBuilder.setIcon(R.drawable.ssl_certificate_enabled_night)
 150         }
 151
 152         // Set the title.
 153         dialogBuilder.setTitle(R.string.ssl_certificate_error)
 154
 155         // Set the view.  The parent view is null because it will be assigned by the alert dialog.
 156         dialogBuilder.setView(layoutInflater.inflate(R.layout.ssl_certificate_error, null))
 157
 158         // Set a listener on the cancel button.
 159         dialogBuilder.setNegativeButton(R.string.cancel) { _: DialogInterface?, _: Int ->
 160             // Check to make sure the SSL error handler is not null.  This might happen if multiple dialogs are displayed at once.
 161             if (sslErrorHandler != null) {
 162                 // Cancel the request.
 163                 sslErrorHandler.cancel()
 164
 165                 // Reset the SSL error handler.
 166                 nestedScrollWebView.resetSslErrorHandler()
 167             }
 168         }
 169
 170         // Set a listener on the proceed button.
 171         dialogBuilder.setPositiveButton(R.string.proceed) { _: DialogInterface?, _: Int ->
 172             // Check to make sure the SSL error handler is not null.  This might happen if multiple dialogs are displayed at once.
 173             if (sslErrorHandler != null) {
 174                 // Proceed to the website.
 175                 sslErrorHandler.proceed()
 176
 177                 // Reset the SSL error handler.
 178                 nestedScrollWebView.resetSslErrorHandler()
 179             }
 180         }
 181
 182         // Create an alert dialog from the builder.
 183         val alertDialog = dialogBuilder.create()
 184
 185         // Get a handle for the shared preferences.
 186         val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)
 187
 188         // Get the screenshot preference.
 189         val allowScreenshots = sharedPreferences.getBoolean(getString(R.string.allow_screenshots_key), false)
 190
 191         // Disable screenshots if not allowed.
 192         if (!allowScreenshots) {
 193             // Disable screenshots.
 194             alertDialog.window!!.addFlags(WindowManager.LayoutParams.FLAG_SECURE)
 195         }
 196
 197         // Get a URI for the URL with errors.
 198         val uriWithErrors = Uri.parse(urlWithErrors)
 199
 200         // Get the IP addresses for the URI.
 201         GetIpAddresses(requireActivity(), alertDialog).execute(uriWithErrors.host)
 202
 203         // The alert dialog must be shown before the contents can be modified.
 204         alertDialog.show()
 205
 206         // Get handles for the views.
 207         val primaryErrorTextView = alertDialog.findViewById<TextView>(R.id.primary_error)!!
 208         val urlTextView = alertDialog.findViewById<TextView>(R.id.url)!!
 209         val issuedToCNameTextView = alertDialog.findViewById<TextView>(R.id.issued_to_cname)!!
 210         val issuedToONameTextView = alertDialog.findViewById<TextView>(R.id.issued_to_oname)!!
 211         val issuedToUNameTextView = alertDialog.findViewById<TextView>(R.id.issued_to_uname)!!
 212         val issuedByTextView = alertDialog.findViewById<TextView>(R.id.issued_by_textview)!!
 213         val issuedByCNameTextView = alertDialog.findViewById<TextView>(R.id.issued_by_cname)!!
 214         val issuedByONameTextView = alertDialog.findViewById<TextView>(R.id.issued_by_oname)!!
 215         val issuedByUNameTextView = alertDialog.findViewById<TextView>(R.id.issued_by_uname)!!
 216         val validDatesTextView = alertDialog.findViewById<TextView>(R.id.valid_dates_textview)!!
 217         val startDateTextView = alertDialog.findViewById<TextView>(R.id.start_date)!!
 218         val endDateTextView = alertDialog.findViewById<TextView>(R.id.end_date)!!
 219
 220         // Setup the common strings.
 221         val urlLabel = getString(R.string.url_label) + "  "
 222         val cNameLabel = getString(R.string.common_name) + "  "
 223         val oNameLabel = getString(R.string.organization) + "  "
 224         val uNameLabel = getString(R.string.organizational_unit) + "  "
 225         val startDateLabel = getString(R.string.start_date) + "  "
 226         val endDateLabel = getString(R.string.end_date) + "  "
 227
 228         // Create a spannable string builder for each text view that needs multiple colors of text.
 229         val urlStringBuilder = SpannableStringBuilder(urlLabel + urlWithErrors)
 230         val issuedToCNameStringBuilder = SpannableStringBuilder(cNameLabel + issuedToCName)
 231         val issuedToONameStringBuilder = SpannableStringBuilder(oNameLabel + issuedToOName)
 232         val issuedToUNameStringBuilder = SpannableStringBuilder(uNameLabel + issuedToUName)
 233         val issuedByCNameStringBuilder = SpannableStringBuilder(cNameLabel + issuedByCName)
 234         val issuedByONameStringBuilder = SpannableStringBuilder(oNameLabel + issuedByOName)
 235         val issuedByUNameStringBuilder = SpannableStringBuilder(uNameLabel + issuedByUName)
 236         val startDateStringBuilder = SpannableStringBuilder(startDateLabel + startDate)
 237         val endDateStringBuilder = SpannableStringBuilder(endDateLabel + endDate)
 238
 239         // Define the color spans.
 240         val blueColorSpan: ForegroundColorSpan
 241         val redColorSpan: ForegroundColorSpan
 242
 243         // Set the color spans according to the theme.  The deprecated `getColor()` must be used until the minimum API >= 23.
 244         if (currentThemeStatus == Configuration.UI_MODE_NIGHT_NO) {
 245             @Suppress("DEPRECATION")
 246             blueColorSpan = ForegroundColorSpan(resources.getColor(R.color.blue_700))
 247             @Suppress("DEPRECATION")
 248             redColorSpan = ForegroundColorSpan(resources.getColor(R.color.red_a700))
 249         } else {
 250             @Suppress("DEPRECATION")
 251             blueColorSpan = ForegroundColorSpan(resources.getColor(R.color.violet_700))
 252             @Suppress("DEPRECATION")
 253             redColorSpan = ForegroundColorSpan(resources.getColor(R.color.red_900))
 254         }
 255
 256         // Setup the spans to display the certificate information in blue.  `SPAN_INCLUSIVE_INCLUSIVE` allows the span to grow in either direction.
 257         urlStringBuilder.setSpan(blueColorSpan, urlLabel.length, urlStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 258         issuedToCNameStringBuilder.setSpan(blueColorSpan, cNameLabel.length, issuedToCNameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 259         issuedToONameStringBuilder.setSpan(blueColorSpan, oNameLabel.length, issuedToONameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 260         issuedToUNameStringBuilder.setSpan(blueColorSpan, uNameLabel.length, issuedToUNameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 261         issuedByCNameStringBuilder.setSpan(blueColorSpan, cNameLabel.length, issuedByCNameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 262         issuedByONameStringBuilder.setSpan(blueColorSpan, oNameLabel.length, issuedByONameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 263         issuedByUNameStringBuilder.setSpan(blueColorSpan, uNameLabel.length, issuedByUNameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 264         startDateStringBuilder.setSpan(blueColorSpan, startDateLabel.length, startDateStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 265         endDateStringBuilder.setSpan(blueColorSpan, endDateLabel.length, endDateStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 266
 267         // Define the primary error string.
 268         var primaryErrorString = ""
 269
 270         // Highlight the primary error in red and store it in the primary error string.
 271         when (primaryErrorInt) {
 272             SslError.SSL_IDMISMATCH -> {
 273                 // Change the URL span colors to red.
 274                 urlStringBuilder.setSpan(redColorSpan, urlLabel.length, urlStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 275                 issuedToCNameStringBuilder.setSpan(redColorSpan, cNameLabel.length, issuedToCNameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 276
 277                 // Store the primary error string.
 278                 primaryErrorString = getString(R.string.cn_mismatch)
 279             }
 280
 281             SslError.SSL_UNTRUSTED -> {
 282                 // Change the issued by text view text to red.  The deprecated `getColor()` must be used until the minimum API >= 23.
 283                 if (currentThemeStatus == Configuration.UI_MODE_NIGHT_NO) {
 284                     @Suppress("DEPRECATION")
 285                     issuedByTextView.setTextColor(resources.getColor(R.color.red_a700))
 286                 } else {
 287                     @Suppress("DEPRECATION")
 288                     issuedByTextView.setTextColor(resources.getColor(R.color.red_900))
 289                 }
 290
 291                 // Change the issued by span color to red.
 292                 issuedByCNameStringBuilder.setSpan(redColorSpan, cNameLabel.length, issuedByCNameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 293                 issuedByONameStringBuilder.setSpan(redColorSpan, oNameLabel.length, issuedByONameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 294                 issuedByUNameStringBuilder.setSpan(redColorSpan, uNameLabel.length, issuedByUNameStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 295
 296                 // Store the primary error string.
 297                 primaryErrorString = getString(R.string.untrusted)
 298             }
 299
 300             SslError.SSL_DATE_INVALID -> {
 301                 // Change the valid dates text view text to red.  The deprecated `getColor()` must be used until the minimum API >= 23.
 302                 if (currentThemeStatus == Configuration.UI_MODE_NIGHT_NO) {
 303                     @Suppress("DEPRECATION")
 304                     validDatesTextView.setTextColor(resources.getColor(R.color.red_a700))
 305                 } else {
 306                     @Suppress("DEPRECATION")
 307                     validDatesTextView.setTextColor(resources.getColor(R.color.red_900))
 308                 }
 309
 310                 // Change the date span colors to red.
 311                 startDateStringBuilder.setSpan(redColorSpan, startDateLabel.length, startDateStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 312                 endDateStringBuilder.setSpan(redColorSpan, endDateLabel.length, endDateStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 313
 314                 // Store the primary error string.
 315                 primaryErrorString = getString(R.string.invalid_date)
 316             }
 317
 318             SslError.SSL_NOTYETVALID -> {
 319                 // Change the start date span color to red.
 320                 startDateStringBuilder.setSpan(redColorSpan, startDateLabel.length, startDateStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 321
 322                 // Store the primary error string.
 323                 primaryErrorString = getString(R.string.future_certificate)
 324             }
 325
 326             SslError.SSL_EXPIRED -> {
 327                 // Change the end date span color to red.
 328                 endDateStringBuilder.setSpan(redColorSpan, endDateLabel.length, endDateStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 329
 330                 // Store the primary error string.
 331                 primaryErrorString = getString(R.string.expired_certificate)
 332             }
 333
 334             SslError.SSL_INVALID ->
 335                 // Store the primary error string.
 336                 primaryErrorString = getString(R.string.invalid_certificate)
 337         }
 338
 339         // Display the strings.
 340         primaryErrorTextView.text = primaryErrorString
 341         urlTextView.text = urlStringBuilder
 342         issuedToCNameTextView.text = issuedToCNameStringBuilder
 343         issuedToONameTextView.text = issuedToONameStringBuilder
 344         issuedToUNameTextView.text = issuedToUNameStringBuilder
 345         issuedByCNameTextView.text = issuedByCNameStringBuilder
 346         issuedByONameTextView.text = issuedByONameStringBuilder
 347         issuedByUNameTextView.text = issuedByUNameStringBuilder
 348         startDateTextView.text = startDateStringBuilder
 349         endDateTextView.text = endDateStringBuilder
 350
 351         // Return the alert dialog.
 352         return alertDialog
 353     }
 354
 355     // This must run asynchronously because it involves a network request.  `String` declares the parameters.  `Void` does not declare progress units.  `SpannableStringBuilder` contains the results.
 356     private class GetIpAddresses constructor(activity: Activity, alertDialog: AlertDialog) : AsyncTask<String, Void?, SpannableStringBuilder>() {
 357         // Define the weak references.
 358         private val activityWeakReference: WeakReference<Activity> = WeakReference(activity)
 359         private val alertDialogWeakReference: WeakReference<AlertDialog> = WeakReference(alertDialog)
 360
 361         override fun doInBackground(vararg domainName: String): SpannableStringBuilder {
 362             // Get handles for the activity and the alert dialog.
 363             val activity = activityWeakReference.get()
 364             val alertDialog = alertDialogWeakReference.get()
 365
 366             // Abort if the activity or the dialog is gone.
 367             if (activity == null || activity.isFinishing || alertDialog == null) {
 368                 return SpannableStringBuilder()
 369             }
 370
 371             // Initialize an IP address string builder.
 372             val ipAddresses = StringBuilder()
 373
 374             // Get an array with the IP addresses for the host.
 375             try {
 376                 // Get an array with all the IP addresses for the domain.
 377                 val inetAddressesArray = InetAddress.getAllByName(domainName[0])
 378
 379                 // Add each IP address to the string builder.
 380                 for (inetAddress in inetAddressesArray) {
 381                     // Check to see if this is not the first IP address.
 382                     if (ipAddresses.isNotEmpty()) {
 383                         // Add a line break to the string builder first.
 384                         ipAddresses.append("\n")
 385                     }
 386
 387                     // Add the IP Address to the string builder.
 388                     ipAddresses.append(inetAddress.hostAddress)
 389                 }
 390             } catch (exception: UnknownHostException) {
 391                 // Do nothing.
 392             }
 393
 394             // Set the label.
 395             val ipAddressesLabel = activity.getString(R.string.ip_addresses) + "  "
 396
 397             // Create a spannable string builder.
 398             val ipAddressesStringBuilder = SpannableStringBuilder(ipAddressesLabel + ipAddresses)
 399
 400             // Create a blue foreground color span.
 401             val blueColorSpan: ForegroundColorSpan
 402
 403             // Get the current theme status.
 404             val currentThemeStatus = activity.resources.configuration.uiMode and Configuration.UI_MODE_NIGHT_MASK
 405
 406             // Set the blue color span according to the theme.  The deprecated `getColor()` must be used until the minimum API >= 23.
 407             blueColorSpan = if (currentThemeStatus == Configuration.UI_MODE_NIGHT_NO) {
 408                 @Suppress("DEPRECATION")
 409                 ForegroundColorSpan(activity.resources.getColor(R.color.blue_700))
 410             } else {
 411                 @Suppress("DEPRECATION")
 412                 ForegroundColorSpan(activity.resources.getColor(R.color.violet_500))
 413             }
 414
 415             // Set the string builder to display the certificate information in blue.  `SPAN_INCLUSIVE_INCLUSIVE` allows the span to grow in either direction.
 416             ipAddressesStringBuilder.setSpan(blueColorSpan, ipAddressesLabel.length, ipAddressesStringBuilder.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE)
 417
 418             // Return the formatted string.
 419             return ipAddressesStringBuilder
 420         }
 421
 422         // `onPostExecute()` operates on the UI thread.
 423         override fun onPostExecute(ipAddresses: SpannableStringBuilder) {
 424             // Get handles for the activity and the alert dialog.
 425             val activity = activityWeakReference.get()
 426             val alertDialog = alertDialogWeakReference.get()
 427
 428             // Abort if the activity or the alert dialog is gone.
 429             if (activity == null || activity.isFinishing || alertDialog == null) {
 430                 return
 431             }
 432
 433             // Get a handle for the IP addresses text view.
 434             val ipAddressesTextView = alertDialog.findViewById<TextView>(R.id.ip_addresses)!!
 435
 436             // Populate the IP addresses text view.
 437             ipAddressesTextView.text = ipAddresses
 438         }
 439     }
 440 }