Adding error handling to ONC validation.

chrome/browser/chromeos/network_settings/onc_validator.cc

Index: chrome/browser/chromeos/network_settings/onc_validator.cc
diff --git a/chrome/browser/chromeos/network_settings/onc_validator.cc b/chrome/browser/chromeos/network_settings/onc_validator.cc
index ec4922797a060dbcef90e6a6490000da59e9260f..dbbc548db3c7bbdd2d0f9ba3bea60d8ea3a7658e 100644
--- a/chrome/browser/chromeos/network_settings/onc_validator.cc
+++ b/chrome/browser/chromeos/network_settings/onc_validator.cc
@@ -7,15 +7,47 @@
 #include <algorithm>
 #include <string>
 
+#include "base/json/json_writer.h"
 #include "base/logging.h"
+#include "base/string_number_conversions.h"
 #include "base/string_util.h"
+#include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/cros/onc_constants.h"
 #include "chrome/browser/chromeos/network_settings/onc_signature.h"
+#include "grit/generated_resources.h"
+#include "ui/base/l10n/l10n_util.h"
 
 namespace chromeos {
 namespace onc {
 
+namespace {
+
+string16 ValueToString(const base::Value& value) {
+  std::string json;
+  base::JSONWriter::Write(&value, &json);
+  return UTF8ToUTF16(json);
+}
+
+// Copied from policy/configuration_policy_handler.cc.
+// TODO(pneubeck): move to a common place like base/.
+string16 ValueTypeToString(Value::Type type) {
+  static const char* strings[] = {
+    "null",
+    "boolean",
+    "integer",
+    "double",
+    "string",
+    "binary",
+    "dictionary",
+    "list"
+  };
+  DCHECK(static_cast<size_t>(type) < arraysize(strings));
+  return ASCIIToUTF16(strings[type]);
+}
+
+}  // namespace
+
 Validator::Validator(
     bool error_on_unknown_field,
     bool error_on_wrong_recommended,
@@ -32,29 +64,45 @@ Validator::~Validator() {
 
 scoped_ptr<base::DictionaryValue> Validator::ValidateAndRepairObject(
     const OncValueSignature* object_signature,
-    const base::DictionaryValue& onc_object) {
+    const base::DictionaryValue& onc_object,
+    std::string* messages) {
   CHECK(object_signature != NULL);
+  messages_.clear();
+  bool error = false;
   scoped_ptr<base::Value> result_value =
-      MapValue(*object_signature, onc_object);
+      MapValue(*object_signature, onc_object, &error);
+  if (error)
+    result_value.reset();
+
   base::DictionaryValue* result_dict = NULL;
   if (result_value.get() != NULL) {
     result_value.release()->GetAsDictionary(&result_dict);
     CHECK(result_dict != NULL);
   }
 
+  if (messages)
+    *messages = JoinMessages();
+
   return make_scoped_ptr(result_dict);
 }
 
 scoped_ptr<base::Value> Validator::MapValue(
     const OncValueSignature& signature,
-    const base::Value& onc_value) {
+    const base::Value& onc_value,
+    bool* error) {
   if (onc_value.GetType() != signature.onc_type) {
     DVLOG(1) << "Wrong type. Expected " << signature.onc_type
              << ", but found " << onc_value.GetType();
+    AddError(l10n_util::GetStringFUTF8(
+        IDS_NETWORK_CONFIG_ERROR_VALUE_HAS_WRONG_TYPE,
+        ValueToString(onc_value), ValueTypeToString(signature.onc_type),
+        ValueTypeToString(onc_value.GetType())));
+    *error = true;
     return scoped_ptr<base::Value>();
   }
 
-  scoped_ptr<base::Value> repaired = Mapper::MapValue(signature, onc_value);
+  scoped_ptr<base::Value> repaired =
+      Mapper::MapValue(signature, onc_value, error);
   if (repaired.get() != NULL)
     CHECK_EQ(repaired->GetType(), signature.onc_type);
   return repaired.Pass();
@@ -62,11 +110,14 @@ scoped_ptr<base::Value> Validator::MapValue(
 
 scoped_ptr<base::DictionaryValue> Validator::MapObject(
     const OncValueSignature& signature,
-    const base::DictionaryValue& onc_object) {
+    const base::DictionaryValue& onc_object,
+    bool* error) {
   scoped_ptr<base::DictionaryValue> repaired(new base::DictionaryValue);
 
   bool valid;
-  if (&signature == &kNetworkConfigurationSignature)
+  if (&signature == &kToplevelConfigurationSignature)
+    valid = ValidateToplevelConfiguration(onc_object, repaired.get());
+  else if (&signature == &kNetworkConfigurationSignature)
     valid = ValidateNetworkConfiguration(onc_object, repaired.get());
   else if (&signature == &kEthernetSignature)
     valid = ValidateEthernet(onc_object, repaired.get());
@@ -93,10 +144,51 @@ scoped_ptr<base::DictionaryValue> Validator::MapObject(
   else
     valid = ValidateObjectDefault(signature, onc_object, repaired.get());
 
-  if (valid)
+  if (valid) {
     return repaired.Pass();
-  else
+  } else {
+    *error = true;
     return scoped_ptr<base::DictionaryValue>();
+  }
+}
+
+scoped_ptr<base::Value> Validator::MapField(
+    const std::string& field_name,
+    const OncValueSignature& object_signature,
+    const base::Value& onc_value,
+    bool* found_unknown_field,
+    bool* error) {
+  path_.push_back(field_name);
+  bool current_field_unknown = false;
+  scoped_ptr<base::Value> result = Mapper::MapField(
+      field_name, object_signature, onc_value, &current_field_unknown, error);
+
+  DCHECK_EQ(field_name, path_.back());
+  path_.pop_back();
+
+  if (current_field_unknown) {
+    *found_unknown_field = true;
+    DVLOG(1) << (error_on_unknown_field_ ? "Error" : "Warning")
+             << ": Unknown field name '" << field_name << "'.";
+    AddMessage(error_on_unknown_field_, l10n_util::GetStringFUTF8(
+        IDS_NETWORK_CONFIG_ERROR_UNKNOWN_FIELD_NAME,
+        UTF8ToUTF16(field_name)));
+  }
+
+  return result.Pass();
+}
+
+scoped_ptr<base::Value> Validator::MapEntry(int index,
+                                            const OncValueSignature& signature,
+                                            const base::Value& onc_value,
+                                            bool* error) {
+  std::string str = base::IntToString(index);
+  path_.push_back(str);
+  scoped_ptr<base::Value> result = Mapper::MapEntry(index, signature,
+                                                    onc_value, error);
+  DCHECK_EQ(str, path_.back());
+  path_.pop_back();
+  return result.Pass();
 }
 
 bool Validator::ValidateObjectDefault(
@@ -107,17 +199,15 @@ bool Validator::ValidateObjectDefault(
   bool nested_error_occured = false;
   MapFields(signature, onc_object, &found_unknown_field, &nested_error_occured,
             result);
-  if (nested_error_occured)
-    return false;
 
-  if (found_unknown_field) {
-    if (error_on_unknown_field_) {
-      DVLOG(1) << "Unknown field name. Aborting.";
-      return false;
-    }
-    DVLOG(1) << "Unknown field name. Ignoring.";
+  if (found_unknown_field && error_on_unknown_field_) {
+    DVLOG(1) << "Unknown field names are errors: Aborting.";
+    return false;
   }
 
+  if (nested_error_occured)
+    return false;
+
   return ValidateRecommendedField(signature, result);
 }
 
@@ -140,8 +230,11 @@ bool Validator::ValidateRecommendedField(
   recommended.reset(recommended_list);
 
   if (!managed_onc_) {
+    AddWarning(l10n_util::GetStringFUTF8(
+        IDS_NETWORK_CONFIG_ERROR_UNEXPECTED_FIELD_IN_UNMANAGED_CONFIG,
+        ASCIIToUTF16(onc::kRecommended)));
     DVLOG(1) << "Found a " << onc::kRecommended
-             << " field in unmanaged ONC. Removing it.";
+             << " field in an unmanaged ONC. Removing it.";
     return true;
   }
 
@@ -169,8 +262,11 @@ bool Validator::ValidateRecommendedField(
     }
 
     if (found_error) {
+      AddMessage(error_on_wrong_recommended_, l10n_util::GetStringFUTF8(
+          IDS_NETWORK_CONFIG_ERROR_UNKNOWN_FIELD_RECOMMENDED,
+          ASCIIToUTF16(field_name)));
       DVLOG(1) << "Found " << error_cause << " field name '" << field_name
-               << "' in kRecommended array. "
+               << "' in a " << onc::kRecommended << " array. "
                << (error_on_wrong_recommended_ ? "Aborting." : "Ignoring.");
       if (error_on_wrong_recommended_)
         return false;
@@ -185,44 +281,42 @@ bool Validator::ValidateRecommendedField(
   return true;
 }
 
-namespace {
+bool Validator::ValidateToplevelConfiguration(
+    const base::DictionaryValue& onc_object,
+    base::DictionaryValue* result) {
+  if (!ValidateObjectDefault(kToplevelConfigurationSignature,
+                             onc_object, result)) {
+    return false;
+  }
 
-std::string JoinStringRange(const char** range_begin,
-                            const char** range_end,
-                            const std::string& separator) {
-  std::vector<std::string> string_vector;
-  std::copy(range_begin, range_end, std::back_inserter(string_vector));
-  return JoinString(string_vector, separator);
-}
+  static const char* kValidTypes[] =
+      { kUnencryptedConfiguration, kEncryptedConfiguration, NULL };
+  if (FieldExistsAndHasNoValueOf(*result, kType, kValidTypes))
+    return false;
 
-bool RequireAnyOf(const std::string &actual, const char** valid_values) {
-  const char** it = valid_values;
-  for (; *it != NULL; ++it) {
-    if (actual == *it)
-      return true;
-  }
-  DVLOG(1) << "Found " << actual << ", but expected one of "
-           << JoinStringRange(valid_values, it, ", ");
-  return false;
-}
+  bool allRequiredExist = true;
 
-bool IsInRange(int actual, int lower_bound, int upper_bound) {
-  if (lower_bound <= actual && actual <= upper_bound)
-    return true;
-  DVLOG(1) << "Found " << actual << ", which is out of range [" << lower_bound
-           << ", " << upper_bound << "]";
-  return false;
-}
+  // Not part of the ONC spec yet:
+  // We don't require the type field and default to UnencryptedConfiguration.
+  std::string type = kUnencryptedConfiguration;
+  result->GetStringWithoutPathExpansion(kType, &type);
+  if (type == kUnencryptedConfiguration &&
+      !result->HasKey(kNetworkConfigurations) &&
+      !result->HasKey(kCertificates)) {
+    DVLOG(1) << "Neither " << kNetworkConfigurations << " nor "
+             << kCertificates << " present.";
+
+    AddMessage(error_on_missing_field_,
+               l10n_util::GetStringFUTF8(
+                   IDS_NETWORK_CONFIG_ERROR_NETWORKS_OR_CERTS_REQUIRED,
+                   ASCIIToUTF16(kNetworkConfigurations),
+                   ASCIIToUTF16(kCertificates)));
+    allRequiredExist = false;
+  }
 
-bool RequireField(const base::DictionaryValue& dict, std::string key) {
-  if (dict.HasKey(key))
-    return true;
-  DVLOG(1) << "Required field " << key << " missing.";
-  return false;
+  return !error_on_missing_field_ || allRequiredExist;
 }
 
-}  // namespace
-
 bool Validator::ValidateNetworkConfiguration(
     const base::DictionaryValue& onc_object,
     base::DictionaryValue* result) {
@@ -231,12 +325,9 @@ bool Validator::ValidateNetworkConfiguration(
     return false;
   }
 
-  std::string type;
   static const char* kValidTypes[] = { kEthernet, kVPN, kWiFi, NULL };
-  if (result->GetStringWithoutPathExpansion(kType, &type) &&
-      !RequireAnyOf(type, kValidTypes)) {
+  if (FieldExistsAndHasNoValueOf(*result, kType, kValidTypes))
     return false;
-  }
 
   bool allRequiredExist = RequireField(*result, kGUID);
 
@@ -245,6 +336,9 @@ bool Validator::ValidateNetworkConfiguration(
   if (!remove) {
     allRequiredExist &= RequireField(*result, kName);
     allRequiredExist &= RequireField(*result, kType);
+
+    std::string type;
+    result->GetStringWithoutPathExpansion(kType, &type);
     allRequiredExist &= type.empty() || RequireField(*result, type);
   }
 
@@ -258,14 +352,15 @@ bool Validator::ValidateEthernet(
   if (!ValidateObjectDefault(kEthernetSignature, onc_object, result))
     return false;
 
-  std::string auth;
   static const char* kValidAuthentications[] = { kNone, k8021X, NULL };
-  if (result->GetStringWithoutPathExpansion(kAuthentication, &auth) &&
-      !RequireAnyOf(auth, kValidAuthentications)) {
+  if (FieldExistsAndHasNoValueOf(*result, kAuthentication,
+                                 kValidAuthentications)) {
     return false;
   }
 
   bool allRequiredExist = true;
+  std::string auth;
+  result->GetStringWithoutPathExpansion(kAuthentication, &auth);
   if (auth == k8021X)
     allRequiredExist &= RequireField(*result, kEAP);
 
@@ -279,19 +374,17 @@ bool Validator::ValidateIPConfig(
   if (!ValidateObjectDefault(kIPConfigSignature, onc_object, result))
     return false;
 
-  std::string type;
   static const char* kValidTypes[] = { kIPv4, kIPv6, NULL };
-  if (result->GetStringWithoutPathExpansion(ipconfig::kType, &type) &&
-      !RequireAnyOf(type, kValidTypes)) {
+  if (FieldExistsAndHasNoValueOf(*result, ipconfig::kType, kValidTypes))
     return false;
-  }
 
-  int routing_prefix;
+  std::string type;
+  result->GetStringWithoutPathExpansion(ipconfig::kType, &type);
   int lower_bound = 1;
   // In case of missing type, choose higher upper_bound.
   int upper_bound = (type == kIPv4) ? 32 : 128;
-  if (result->GetIntegerWithoutPathExpansion(kRoutingPrefix, &routing_prefix) &&
-      !IsInRange(routing_prefix, lower_bound, upper_bound)) {
+  if (FieldExistsAndIsNotInRange(*result, kRoutingPrefix,
+                                 lower_bound, upper_bound)) {
     return false;
   }
 
@@ -309,16 +402,16 @@ bool Validator::ValidateWiFi(
   if (!ValidateObjectDefault(kWiFiSignature, onc_object, result))
     return false;
 
-  std::string security;
   static const char* kValidSecurities[] =
       { kNone, kWEP_PSK, kWEP_8021X, kWPA_PSK, kWPA_EAP, NULL };
-  if (result->GetStringWithoutPathExpansion(kSecurity, &security) &&
-      !RequireAnyOf(security, kValidSecurities)) {
+  if (FieldExistsAndHasNoValueOf(*result, kSecurity, kValidSecurities))
     return false;
-  }
 
   bool allRequiredExist = RequireField(*result, kSecurity) &
       RequireField(*result, kSSID);
+
+  std::string security;
+  result->GetStringWithoutPathExpansion(kSecurity, &security);
   if (security == kWEP_8021X || security == kWPA_EAP)
     allRequiredExist &= RequireField(*result, kEAP);
   else if (security == kWEP_PSK || security == kWPA_PSK)
@@ -334,16 +427,14 @@ bool Validator::ValidateVPN(
   if (!ValidateObjectDefault(kVPNSignature, onc_object, result))
     return false;
 
-  std::string type;
   static const char* kValidTypes[] =
       { kIPsec, kTypeL2TP_IPsec, kOpenVPN, NULL };
-  if (result->GetStringWithoutPathExpansion(vpn::kType, &type) &&
-      !RequireAnyOf(type, kValidTypes)) {
+  if (FieldExistsAndHasNoValueOf(*result, vpn::kType, kValidTypes))
     return false;
-  }
 
   bool allRequiredExist = RequireField(*result, vpn::kType);
-
+  std::string type;
+  result->GetStringWithoutPathExpansion(vpn::kType, &type);
   if (type == kOpenVPN) {
     allRequiredExist &= RequireField(*result, kOpenVPN);
   } else if (type == kIPsec) {
@@ -364,26 +455,24 @@ bool Validator::ValidateIPsec(
   if (!ValidateObjectDefault(kIPsecSignature, onc_object, result))
     return false;
 
-  std::string auth;
   static const char* kValidAuthentications[] = { kPSK, kCert, NULL };
-  if (result->GetStringWithoutPathExpansion(kAuthenticationType, &auth) &&
-      !RequireAnyOf(auth, kValidAuthentications)) {
-    return false;
-  }
-
-  std::string cert_type;
   static const char* kValidCertTypes[] = { kRef, kPattern, NULL };
-  if (result->GetStringWithoutPathExpansion(kClientCertType, &cert_type) &&
-      !RequireAnyOf(cert_type, kValidCertTypes)) {
+  if (FieldExistsAndHasNoValueOf(*result, kAuthenticationType,
+                                 kValidAuthentications) |
+      FieldExistsAndHasNoValueOf(*result, kClientCertType, kValidCertTypes)) {
     return false;
   }
 
   bool allRequiredExist = RequireField(*result, kAuthenticationType) &
       RequireField(*result, kIKEVersion);
+  std::string auth;
+  result->GetStringWithoutPathExpansion(kAuthenticationType, &auth);
   if (auth == kCert) {
     allRequiredExist &= RequireField(*result, kClientCertType) &
         RequireField(*result, kServerCARef);
   }
+  std::string cert_type;
+  result->GetStringWithoutPathExpansion(kClientCertType, &cert_type);
   if (cert_type == kPattern)
     allRequiredExist &= RequireField(*result, kClientCertPattern);
   else if (cert_type == kRef)
@@ -401,31 +490,23 @@ bool Validator::ValidateOpenVPN(
   if (!ValidateObjectDefault(kOpenVPNSignature, onc_object, result))
     return false;
 
-  std::string auth_retry;
   static const char* kValidAuthRetryValues[] =
       { openvpn::kNone, kInteract, kNoInteract, NULL };
-  if (result->GetStringWithoutPathExpansion(kAuthRetry, &auth_retry) &&
-      !RequireAnyOf(auth_retry, kValidAuthRetryValues)) {
-    return false;
-  }
-
-  std::string cert_type;
   static const char* kValidCertTypes[] =
       { certificate::kNone, kRef, kPattern, NULL };
-  if (result->GetStringWithoutPathExpansion(kClientCertType, &cert_type) &&
-      !RequireAnyOf(cert_type, kValidCertTypes)) {
-    return false;
-  }
-
-  std::string cert_tls;
   static const char* kValidCertTlsValues[] =
       { openvpn::kNone, openvpn::kServer, NULL };
-  if (result->GetStringWithoutPathExpansion(kRemoteCertTLS, &cert_tls) &&
-      !RequireAnyOf(cert_tls, kValidCertTlsValues)) {
+
+  if (FieldExistsAndHasNoValueOf(*result, kAuthRetry, kValidAuthRetryValues) |
+      FieldExistsAndHasNoValueOf(*result, kClientCertType, kValidCertTypes) |
+      FieldExistsAndHasNoValueOf(*result, kRemoteCertTLS,
+                                 kValidCertTlsValues)) {
     return false;
   }
 
   bool allRequiredExist = RequireField(*result, kClientCertType);
+  std::string cert_type;
+  result->GetStringWithoutPathExpansion(kClientCertType, &cert_type);
   if (cert_type == kPattern)
     allRequiredExist &= RequireField(*result, kClientCertPattern);
   else if (cert_type == kRef)
@@ -458,15 +539,13 @@ bool Validator::ValidateProxySettings(const base::DictionaryValue& onc_object,
   if (!ValidateObjectDefault(kProxySettingsSignature, onc_object, result))
     return false;
 
-  std::string type;
   static const char* kValidTypes[] = { kDirect, kManual, kPAC, kWPAD, NULL };
-  if (result->GetStringWithoutPathExpansion(proxy::kType, &type) &&
-      !RequireAnyOf(type, kValidTypes)) {
+  if (FieldExistsAndHasNoValueOf(*result, proxy::kType, kValidTypes))
     return false;
-  }
 
   bool allRequiredExist = RequireField(*result, proxy::kType);
-
+  std::string type;
+  result->GetStringWithoutPathExpansion(proxy::kType, &type);
   if (type == kManual)
     allRequiredExist &= RequireField(*result, kManual);
   else if (type == kPAC)
@@ -494,32 +573,22 @@ bool Validator::ValidateEAP(const base::DictionaryValue& onc_object,
   if (!ValidateObjectDefault(kEAPSignature, onc_object, result))
     return false;
 
-  std::string inner;
   static const char* kValidInnerValues[] =
       { kAutomatic, kMD5, kMSCHAPv2, kPAP, NULL };
-  if (result->GetStringWithoutPathExpansion(kInner, &inner) &&
-      !RequireAnyOf(inner, kValidInnerValues)) {
-    return false;
-  }
-
-  std::string outer;
   static const char* kValidOuterValues[] =
       { kPEAP, kEAP_TLS, kEAP_TTLS, kLEAP, kEAP_SIM, kEAP_FAST, kEAP_AKA,
         NULL };
-  if (result->GetStringWithoutPathExpansion(kOuter, &outer) &&
-      !RequireAnyOf(outer, kValidOuterValues)) {
-    return false;
-  }
-
-  std::string cert_type;
   static const char* kValidCertTypes[] = { kRef, kPattern, NULL };
-  if (result->GetStringWithoutPathExpansion(kClientCertType, &cert_type) &&
-      !RequireAnyOf(cert_type, kValidCertTypes )) {
+
+  if (FieldExistsAndHasNoValueOf(*result, kInner, kValidInnerValues) |
+      FieldExistsAndHasNoValueOf(*result, kOuter, kValidOuterValues) |
+      FieldExistsAndHasNoValueOf(*result, kClientCertType, kValidCertTypes)) {
     return false;
   }
 
   bool allRequiredExist = RequireField(*result, kOuter);
-
+  std::string cert_type;
+  result->GetStringWithoutPathExpansion(kClientCertType, &cert_type);
   if (cert_type == kPattern)
     allRequiredExist &= RequireField(*result, kClientCertPattern);
   else if (cert_type == kRef)
@@ -535,12 +604,9 @@ bool Validator::ValidateCertificate(
   if (!ValidateObjectDefault(kCertificateSignature, onc_object, result))
     return false;
 
-  std::string type;
   static const char* kValidTypes[] = { kClient, kServer, kAuthority, NULL };
-  if (result->GetStringWithoutPathExpansion(certificate::kType, &type) &&
-      !RequireAnyOf(type, kValidTypes)) {
+  if (FieldExistsAndHasNoValueOf(*result, certificate::kType, kValidTypes))
     return false;
-  }
 
   bool allRequiredExist = RequireField(*result, kGUID);
 
@@ -549,6 +615,8 @@ bool Validator::ValidateCertificate(
   if (!remove) {
     allRequiredExist &= RequireField(*result, certificate::kType);
 
+    std::string type;
+    result->GetStringWithoutPathExpansion(certificate::kType, &type);
     if (type == kClient)
       allRequiredExist &= RequireField(*result, kPKCS12);
     else if (type == kServer || type == kAuthority)
@@ -558,5 +626,105 @@ bool Validator::ValidateCertificate(
   return !error_on_missing_field_ || allRequiredExist;
 }
 
+namespace {
+
+std::string JoinStringRange(const char** range_begin,
+                            const char** range_end,
+                            const std::string& separator) {
+  std::vector<std::string> string_vector;
+  std::copy(range_begin, range_end, std::back_inserter(string_vector));
+  return JoinString(string_vector, separator);
+}
+
+}  // namespace
+
+bool Validator::FieldExistsAndHasNoValueOf(const base::DictionaryValue& object,
+                                           const std::string &field_name,
+                                           const char** valid_values) {
+  std::string actual_value;
+  if (!object.GetStringWithoutPathExpansion(field_name, &actual_value))
+    return false;
+
+  const char** it = valid_values;
+  for (; *it != NULL; ++it) {
+    if (actual_value == *it)
+      return false;
+  }
+  std::string valid_values_str =
+      "[" + JoinStringRange(valid_values, it, ", ") + "]";
+  path_.push_back(field_name);
+  AddError(l10n_util::GetStringFUTF8(
+      IDS_NETWORK_CONFIG_ERROR_INVALID_VALUE,
+      UTF8ToUTF16(actual_value),
+      UTF8ToUTF16(valid_values_str)));
+  path_.pop_back();
+  DVLOG(1) << "Found " << actual_value << ", but expected one of "
+           << valid_values_str;
+  return true;
+}
+
+bool Validator::FieldExistsAndIsNotInRange(const base::DictionaryValue& object,
+                                           const std::string &field_name,
+                                           int lower_bound,
+                                           int upper_bound) {
+  int actual_value;
+  if (!object.GetIntegerWithoutPathExpansion(field_name, &actual_value))
+    return false;
+
+  if (lower_bound <= actual_value && actual_value <= upper_bound)
+    return false;
+  path_.push_back(field_name);
+  AddError(l10n_util::GetStringFUTF8(
+      IDS_NETWORK_CONFIG_ERROR_VALUE_OUT_OF_RANGE,
+      base::IntToString16(actual_value),
+      base::IntToString16(lower_bound),
+      base::IntToString16(upper_bound)));
+  path_.pop_back();
+  DVLOG(1) << "Found " << actual_value << ", which is out of range ["
+           << lower_bound << ", " << upper_bound << "]";
+  return true;
+}
+
+bool Validator::RequireField(const base::DictionaryValue& dict,
+                             const std::string& field_name) {
+  if (dict.HasKey(field_name))
+    return true;
+  AddError(l10n_util::GetStringFUTF8(
+      IDS_NETWORK_CONFIG_ERROR_REQUIRED_FIELD_MISSING,
+      UTF8ToUTF16(field_name)));
+  DVLOG(1) << "Required field " << field_name << " missing.";
+  return false;
+}
+
+void Validator::AddWarning(const std::string& msg) {
+  AddMessage(false, msg);
+}
+
+void Validator::AddError(const std::string& msg) {
+  AddMessage(true, msg);
+}
+
+void Validator::AddMessage(bool is_error, const std::string& sub_message) {
+  std::string message;
+  if (path_.empty()) {
+    int message_id = is_error ? IDS_NETWORK_CONFIG_ERROR_AT_TOPLEVEL
+        : IDS_NETWORK_CONFIG_WARNING_AT_TOPLEVEL;
+    message = l10n_util::GetStringUTF8(message_id);
+  } else {
+    int message_id = is_error ?
+        IDS_NETWORK_CONFIG_ERROR_AT_PATH :
+        IDS_NETWORK_CONFIG_WARNING_AT_PATH;
+    message = l10n_util::GetStringFUTF8(message_id,
+                                        ASCIIToUTF16(JoinString(path_, ".")));
+  }
+  message.append(" ");
+  message.append(sub_message);
+  messages_.push_back(message);
+}
+
+std::string Validator::JoinMessages() {
+  return JoinString(messages_, "\n");
+}
+
 }  // namespace onc
 }  // namespace chromeos