Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 798 insertions, 0 deletions

diff --git a/third_party/libwebrtc/api/transport/stun.h b/third_party/libwebrtc/api/transport/stun.h
new file mode 100644
index 0000000000..c2c9ad4b9c
--- /dev/null
+++ b/third_party/libwebrtc/api/transport/stun.h
@@ -0,0 +1,798 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef API_TRANSPORT_STUN_H_
+#define API_TRANSPORT_STUN_H_
+
+// This file contains classes for dealing with the STUN protocol, as specified
+// in RFC 5389, and its descendants.
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <functional>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/array_view.h"
+#include "rtc_base/byte_buffer.h"
+#include "rtc_base/ip_address.h"
+#include "rtc_base/socket_address.h"
+
+namespace cricket {
+
+// These are the types of STUN messages defined in RFC 5389.
+enum StunMessageType : uint16_t {
+  STUN_INVALID_MESSAGE_TYPE = 0x0000,
+  STUN_BINDING_REQUEST = 0x0001,
+  STUN_BINDING_INDICATION = 0x0011,
+  STUN_BINDING_RESPONSE = 0x0101,
+  STUN_BINDING_ERROR_RESPONSE = 0x0111,
+
+  // Method 0x80, GOOG-PING is a variant of STUN BINDING
+  // that is sent instead of a STUN BINDING if the binding
+  // was identical to the one before.
+  GOOG_PING_REQUEST = 0x200,
+  GOOG_PING_RESPONSE = 0x300,
+  GOOG_PING_ERROR_RESPONSE = 0x310,
+};
+
+// These are all known STUN attributes, defined in RFC 5389 and elsewhere.
+// Next to each is the name of the class (T is StunTAttribute) that implements
+// that type.
+// RETRANSMIT_COUNT is the number of outstanding pings without a response at
+// the time the packet is generated.
+enum StunAttributeType {
+  STUN_ATTR_MAPPED_ADDRESS = 0x0001,      // Address
+  STUN_ATTR_USERNAME = 0x0006,            // ByteString
+  STUN_ATTR_MESSAGE_INTEGRITY = 0x0008,   // ByteString, 20 bytes
+  STUN_ATTR_ERROR_CODE = 0x0009,          // ErrorCode
+  STUN_ATTR_UNKNOWN_ATTRIBUTES = 0x000a,  // UInt16List
+  STUN_ATTR_REALM = 0x0014,               // ByteString
+  STUN_ATTR_NONCE = 0x0015,               // ByteString
+  STUN_ATTR_XOR_MAPPED_ADDRESS = 0x0020,  // XorAddress
+  STUN_ATTR_SOFTWARE = 0x8022,            // ByteString
+  STUN_ATTR_ALTERNATE_SERVER = 0x8023,    // Address
+  STUN_ATTR_FINGERPRINT = 0x8028,         // UInt32
+  STUN_ATTR_RETRANSMIT_COUNT = 0xFF00     // UInt32
+};
+
+// These are the types of the values associated with the attributes above.
+// This allows us to perform some basic validation when reading or adding
+// attributes. Note that these values are for our own use, and not defined in
+// RFC 5389.
+enum StunAttributeValueType {
+  STUN_VALUE_UNKNOWN = 0,
+  STUN_VALUE_ADDRESS = 1,
+  STUN_VALUE_XOR_ADDRESS = 2,
+  STUN_VALUE_UINT32 = 3,
+  STUN_VALUE_UINT64 = 4,
+  STUN_VALUE_BYTE_STRING = 5,
+  STUN_VALUE_ERROR_CODE = 6,
+  STUN_VALUE_UINT16_LIST = 7
+};
+
+// These are the types of STUN addresses defined in RFC 5389.
+enum StunAddressFamily {
+  // NB: UNDEF is not part of the STUN spec.
+  STUN_ADDRESS_UNDEF = 0,
+  STUN_ADDRESS_IPV4 = 1,
+  STUN_ADDRESS_IPV6 = 2
+};
+
+// These are the types of STUN error codes defined in RFC 5389.
+enum StunErrorCode {
+  STUN_ERROR_TRY_ALTERNATE = 300,
+  STUN_ERROR_BAD_REQUEST = 400,
+  STUN_ERROR_UNAUTHORIZED = 401,
+  STUN_ERROR_UNKNOWN_ATTRIBUTE = 420,
+  STUN_ERROR_STALE_NONCE = 438,
+  STUN_ERROR_SERVER_ERROR = 500,
+  STUN_ERROR_GLOBAL_FAILURE = 600
+};
+
+// Strings for the error codes above.
+extern const char STUN_ERROR_REASON_TRY_ALTERNATE_SERVER[];
+extern const char STUN_ERROR_REASON_BAD_REQUEST[];
+extern const char STUN_ERROR_REASON_UNAUTHORIZED[];
+extern const char STUN_ERROR_REASON_UNKNOWN_ATTRIBUTE[];
+extern const char STUN_ERROR_REASON_STALE_NONCE[];
+extern const char STUN_ERROR_REASON_SERVER_ERROR[];
+
+// The mask used to determine whether a STUN message is a request/response etc.
+const uint32_t kStunTypeMask = 0x0110;
+
+// STUN Attribute header length.
+const size_t kStunAttributeHeaderSize = 4;
+
+// Following values correspond to RFC5389.
+const size_t kStunHeaderSize = 20;
+const size_t kStunTransactionIdOffset = 8;
+const size_t kStunTransactionIdLength = 12;
+const uint32_t kStunMagicCookie = 0x2112A442;
+constexpr size_t kStunMagicCookieLength = sizeof(kStunMagicCookie);
+
+// Following value corresponds to an earlier version of STUN from
+// RFC3489.
+const size_t kStunLegacyTransactionIdLength = 16;
+
+// STUN Message Integrity HMAC length.
+const size_t kStunMessageIntegritySize = 20;
+// Size of STUN_ATTR_MESSAGE_INTEGRITY_32
+const size_t kStunMessageIntegrity32Size = 4;
+
+class StunAddressAttribute;
+class StunAttribute;
+class StunByteStringAttribute;
+class StunErrorCodeAttribute;
+class StunUInt16ListAttribute;
+class StunUInt32Attribute;
+class StunUInt64Attribute;
+class StunXorAddressAttribute;
+
+// Records a complete STUN/TURN message.  Each message consists of a type and
+// any number of attributes.  Each attribute is parsed into an instance of an
+// appropriate class (see above).  The Get* methods will return instances of
+// that attribute class.
+class StunMessage {
+ public:
+  // Constructs a StunMessage with an invalid type and empty, legacy length
+  // (16 bytes, RFC3489) transaction id.
+  StunMessage();
+
+  // Construct a `StunMessage` with a specific type and generate a new
+  // 12 byte transaction id (RFC5389).
+  explicit StunMessage(uint16_t type);
+
+  StunMessage(uint16_t type, absl::string_view transaction_id);
+
+  virtual ~StunMessage();
+
+  // The verification status of the message. This is checked on parsing,
+  // or set by AddMessageIntegrity.
+  // These values are persisted to logs. Entries should not be renumbered and
+  // numeric values should never be reused.
+  enum class IntegrityStatus {
+    kNotSet = 0,
+    kNoIntegrity = 1,   // Message-integrity attribute missing
+    kIntegrityOk = 2,   // Message-integrity checked OK
+    kIntegrityBad = 3,  // Message-integrity verification failed
+    kMaxValue = kIntegrityBad,
+  };
+
+  int type() const { return type_; }
+  size_t length() const { return length_; }
+  const std::string& transaction_id() const { return transaction_id_; }
+  uint32_t reduced_transaction_id() const { return reduced_transaction_id_; }
+
+  // Returns true if the message confirms to RFC3489 rather than
+  // RFC5389. The main difference between the two versions of the STUN
+  // protocol is the presence of the magic cookie and different length
+  // of transaction ID. For outgoing packets the version of the protocol
+  // is determined by the lengths of the transaction ID.
+  bool IsLegacy() const;
+
+  [[deprecated]] void SetType(int type) { type_ = static_cast<uint16_t>(type); }
+  [[deprecated]] bool SetTransactionID(absl::string_view transaction_id) {
+    if (!IsValidTransactionId(transaction_id))
+      return false;
+    SetTransactionIdForTesting(transaction_id);
+    return true;
+  }
+
+  // Get a list of all of the attribute types in the "comprehension required"
+  // range that were not recognized.
+  std::vector<uint16_t> GetNonComprehendedAttributes() const;
+
+  // Gets the desired attribute value, or NULL if no such attribute type exists.
+  const StunAddressAttribute* GetAddress(int type) const;
+  const StunUInt32Attribute* GetUInt32(int type) const;
+  const StunUInt64Attribute* GetUInt64(int type) const;
+  const StunByteStringAttribute* GetByteString(int type) const;
+  const StunUInt16ListAttribute* GetUInt16List(int type) const;
+
+  // Gets these specific attribute values.
+  const StunErrorCodeAttribute* GetErrorCode() const;
+  // Returns the code inside the error code attribute, if present, and
+  // STUN_ERROR_GLOBAL_FAILURE otherwise.
+  int GetErrorCodeValue() const;
+  const StunUInt16ListAttribute* GetUnknownAttributes() const;
+
+  // Takes ownership of the specified attribute and adds it to the message.
+  void AddAttribute(std::unique_ptr<StunAttribute> attr);
+
+  // Remove the last occurrence of an attribute.
+  std::unique_ptr<StunAttribute> RemoveAttribute(int type);
+
+  // Remote all attributes and releases them.
+  void ClearAttributes();
+
+  // Validates that a STUN message has a correct MESSAGE-INTEGRITY value.
+  // This uses the buffered raw-format message stored by Read().
+  IntegrityStatus ValidateMessageIntegrity(const std::string& password);
+
+  // Revalidates the STUN message with (possibly) a new password.
+  // Indicates that calling logic needs review - probably previous call
+  // was checking with the wrong password.
+  IntegrityStatus RevalidateMessageIntegrity(const std::string& password);
+
+  // Returns the current integrity status of the message.
+  IntegrityStatus integrity() const { return integrity_; }
+
+  // Shortcut for checking if integrity is verified.
+  bool IntegrityOk() const {
+    return integrity_ == IntegrityStatus::kIntegrityOk;
+  }
+
+  // Returns the password attribute used to set or check the integrity.
+  // Can only be called after adding or checking the integrity.
+  std::string password() const {
+    RTC_DCHECK(integrity_ != IntegrityStatus::kNotSet);
+    return password_;
+  }
+
+  // Adds a MESSAGE-INTEGRITY attribute that is valid for the current message.
+  bool AddMessageIntegrity(absl::string_view password);
+
+  // Adds a STUN_ATTR_GOOG_MESSAGE_INTEGRITY_32 attribute that is valid for the
+  // current message.
+  bool AddMessageIntegrity32(absl::string_view password);
+
+  // Verify that a buffer has stun magic cookie and one of the specified
+  // methods. Note that it does not check for the existance of FINGERPRINT.
+  static bool IsStunMethod(rtc::ArrayView<int> methods,
+                           const char* data,
+                           size_t size);
+
+  // Verifies that a given buffer is STUN by checking for a correct FINGERPRINT.
+  static bool ValidateFingerprint(const char* data, size_t size);
+
+  // Generates a new 12 byte (RFC5389) transaction id.
+  static std::string GenerateTransactionId();
+
+  // Adds a FINGERPRINT attribute that is valid for the current message.
+  bool AddFingerprint();
+
+  // Parses the STUN packet in the given buffer and records it here. The
+  // return value indicates whether this was successful.
+  bool Read(rtc::ByteBufferReader* buf);
+
+  // Writes this object into a STUN packet. The return value indicates whether
+  // this was successful.
+  bool Write(rtc::ByteBufferWriter* buf) const;
+
+  // Creates an empty message. Overridable by derived classes.
+  virtual StunMessage* CreateNew() const;
+
+  // Modify the stun magic cookie used for this STUN message.
+  // This is used for testing.
+  [[deprecated]] void SetStunMagicCookie(uint32_t val);
+
+  // Change the internal transaction id. Used only for testing.
+  void SetTransactionIdForTesting(absl::string_view transaction_id);
+
+  // Contruct a copy of `this`.
+  std::unique_ptr<StunMessage> Clone() const;
+
+  // Check if the attributes of this StunMessage equals those of `other`
+  // for all attributes that `attribute_type_mask` return true
+  bool EqualAttributes(const StunMessage* other,
+                       std::function<bool(int type)> attribute_type_mask) const;
+
+  // Validates that a STUN message in byte buffer form
+  // has a correct MESSAGE-INTEGRITY value.
+  // These functions are not recommended and will be deprecated; use
+  // ValidateMessageIntegrity(password) on the parsed form instead.
+  [[deprecated("Use member function")]] static bool ValidateMessageIntegrity(
+      const char* data,
+      size_t size,
+      const std::string& password);
+  [[deprecated("Use member function")]] static bool ValidateMessageIntegrity32(
+      const char* data,
+      size_t size,
+      const std::string& password);
+
+  // Expose raw-buffer ValidateMessageIntegrity function for testing.
+  static bool ValidateMessageIntegrityForTesting(const char* data,
+                                                 size_t size,
+                                                 const std::string& password);
+  // Expose raw-buffer ValidateMessageIntegrity function for testing.
+  static bool ValidateMessageIntegrity32ForTesting(const char* data,
+                                                   size_t size,
+                                                   const std::string& password);
+
+ protected:
+  // Verifies that the given attribute is allowed for this message.
+  virtual StunAttributeValueType GetAttributeValueType(int type) const;
+
+  std::vector<std::unique_ptr<StunAttribute>> attrs_;
+
+ private:
+  StunAttribute* CreateAttribute(int type, size_t length) /* const*/;
+  const StunAttribute* GetAttribute(int type) const;
+  static bool IsValidTransactionId(absl::string_view transaction_id);
+  bool AddMessageIntegrityOfType(int mi_attr_type,
+                                 size_t mi_attr_size,
+                                 absl::string_view key);
+  static bool ValidateMessageIntegrityOfType(int mi_attr_type,
+                                             size_t mi_attr_size,
+                                             const char* data,
+                                             size_t size,
+                                             const std::string& password);
+
+  uint16_t type_ = STUN_INVALID_MESSAGE_TYPE;
+  uint16_t length_ = 0;
+  std::string transaction_id_;
+  uint32_t reduced_transaction_id_ = 0;
+  uint32_t stun_magic_cookie_ = kStunMagicCookie;
+  // The original buffer for messages created by Read().
+  std::string buffer_;
+  IntegrityStatus integrity_ = IntegrityStatus::kNotSet;
+  std::string password_;
+};
+
+// Base class for all STUN/TURN attributes.
+class StunAttribute {
+ public:
+  virtual ~StunAttribute() {}
+
+  int type() const { return type_; }
+  size_t length() const { return length_; }
+
+  // Return the type of this attribute.
+  virtual StunAttributeValueType value_type() const = 0;
+
+  // Only XorAddressAttribute needs this so far.
+  virtual void SetOwner(StunMessage* owner) {}
+
+  // Reads the body (not the type or length) for this type of attribute from
+  // the given buffer.  Return value is true if successful.
+  virtual bool Read(rtc::ByteBufferReader* buf) = 0;
+
+  // Writes the body (not the type or length) to the given buffer.  Return
+  // value is true if successful.
+  virtual bool Write(rtc::ByteBufferWriter* buf) const = 0;
+
+  // Creates an attribute object with the given type and smallest length.
+  static StunAttribute* Create(StunAttributeValueType value_type,
+                               uint16_t type,
+                               uint16_t length,
+                               StunMessage* owner);
+  // TODO(?): Allow these create functions to take parameters, to reduce
+  // the amount of work callers need to do to initialize attributes.
+  static std::unique_ptr<StunAddressAttribute> CreateAddress(uint16_t type);
+  static std::unique_ptr<StunXorAddressAttribute> CreateXorAddress(
+      uint16_t type);
+  static std::unique_ptr<StunUInt32Attribute> CreateUInt32(uint16_t type);
+  static std::unique_ptr<StunUInt64Attribute> CreateUInt64(uint16_t type);
+  static std::unique_ptr<StunByteStringAttribute> CreateByteString(
+      uint16_t type);
+  static std::unique_ptr<StunUInt16ListAttribute> CreateUInt16ListAttribute(
+      uint16_t type);
+  static std::unique_ptr<StunErrorCodeAttribute> CreateErrorCode();
+  static std::unique_ptr<StunUInt16ListAttribute> CreateUnknownAttributes();
+
+ protected:
+  StunAttribute(uint16_t type, uint16_t length);
+  void SetLength(uint16_t length) { length_ = length; }
+  void WritePadding(rtc::ByteBufferWriter* buf) const;
+  void ConsumePadding(rtc::ByteBufferReader* buf) const;
+
+ private:
+  uint16_t type_;
+  uint16_t length_;
+};
+
+// Implements STUN attributes that record an Internet address.
+class StunAddressAttribute : public StunAttribute {
+ public:
+  static const uint16_t SIZE_UNDEF = 0;
+  static const uint16_t SIZE_IP4 = 8;
+  static const uint16_t SIZE_IP6 = 20;
+  StunAddressAttribute(uint16_t type, const rtc::SocketAddress& addr);
+  StunAddressAttribute(uint16_t type, uint16_t length);
+
+  StunAttributeValueType value_type() const override;
+
+  StunAddressFamily family() const {
+    switch (address_.ipaddr().family()) {
+      case AF_INET:
+        return STUN_ADDRESS_IPV4;
+      case AF_INET6:
+        return STUN_ADDRESS_IPV6;
+    }
+    return STUN_ADDRESS_UNDEF;
+  }
+
+  const rtc::SocketAddress& GetAddress() const { return address_; }
+  const rtc::IPAddress& ipaddr() const { return address_.ipaddr(); }
+  uint16_t port() const { return address_.port(); }
+
+  void SetAddress(const rtc::SocketAddress& addr) {
+    address_ = addr;
+    EnsureAddressLength();
+  }
+  void SetIP(const rtc::IPAddress& ip) {
+    address_.SetIP(ip);
+    EnsureAddressLength();
+  }
+  void SetPort(uint16_t port) { address_.SetPort(port); }
+
+  bool Read(rtc::ByteBufferReader* buf) override;
+  bool Write(rtc::ByteBufferWriter* buf) const override;
+
+ private:
+  void EnsureAddressLength() {
+    switch (family()) {
+      case STUN_ADDRESS_IPV4: {
+        SetLength(SIZE_IP4);
+        break;
+      }
+      case STUN_ADDRESS_IPV6: {
+        SetLength(SIZE_IP6);
+        break;
+      }
+      default: {
+        SetLength(SIZE_UNDEF);
+        break;
+      }
+    }
+  }
+  rtc::SocketAddress address_;
+};
+
+// Implements STUN attributes that record an Internet address. When encoded
+// in a STUN message, the address contained in this attribute is XORed with the
+// transaction ID of the message.
+class StunXorAddressAttribute : public StunAddressAttribute {
+ public:
+  StunXorAddressAttribute(uint16_t type, const rtc::SocketAddress& addr);
+  StunXorAddressAttribute(uint16_t type, uint16_t length, StunMessage* owner);
+
+  StunAttributeValueType value_type() const override;
+  void SetOwner(StunMessage* owner) override;
+  bool Read(rtc::ByteBufferReader* buf) override;
+  bool Write(rtc::ByteBufferWriter* buf) const override;
+
+ private:
+  rtc::IPAddress GetXoredIP() const;
+  StunMessage* owner_;
+};
+
+// Implements STUN attributes that record a 32-bit integer.
+class StunUInt32Attribute : public StunAttribute {
+ public:
+  static const uint16_t SIZE = 4;
+  StunUInt32Attribute(uint16_t type, uint32_t value);
+  explicit StunUInt32Attribute(uint16_t type);
+
+  StunAttributeValueType value_type() const override;
+
+  uint32_t value() const { return bits_; }
+  void SetValue(uint32_t bits) { bits_ = bits; }
+
+  bool GetBit(size_t index) const;
+  void SetBit(size_t index, bool value);
+
+  bool Read(rtc::ByteBufferReader* buf) override;
+  bool Write(rtc::ByteBufferWriter* buf) const override;
+
+ private:
+  uint32_t bits_;
+};
+
+class StunUInt64Attribute : public StunAttribute {
+ public:
+  static const uint16_t SIZE = 8;
+  StunUInt64Attribute(uint16_t type, uint64_t value);
+  explicit StunUInt64Attribute(uint16_t type);
+
+  StunAttributeValueType value_type() const override;
+
+  uint64_t value() const { return bits_; }
+  void SetValue(uint64_t bits) { bits_ = bits; }
+
+  bool Read(rtc::ByteBufferReader* buf) override;
+  bool Write(rtc::ByteBufferWriter* buf) const override;
+
+ private:
+  uint64_t bits_;
+};
+
+// Implements STUN attributes that record an arbitrary byte string.
+class StunByteStringAttribute : public StunAttribute {
+ public:
+  explicit StunByteStringAttribute(uint16_t type);
+  StunByteStringAttribute(uint16_t type, absl::string_view str);
+  StunByteStringAttribute(uint16_t type, const void* bytes, size_t length);
+  StunByteStringAttribute(uint16_t type, uint16_t length);
+  ~StunByteStringAttribute() override;
+
+  StunAttributeValueType value_type() const override;
+
+  const char* bytes() const { return bytes_; }
+  absl::string_view string_view() const {
+    return absl::string_view(bytes_, length());
+  }
+
+  [[deprecated]] std::string GetString() const {
+    return std::string(bytes_, length());
+  }
+
+  void CopyBytes(const void* bytes, size_t length);
+  void CopyBytes(absl::string_view bytes);
+
+  uint8_t GetByte(size_t index) const;
+  void SetByte(size_t index, uint8_t value);
+
+  bool Read(rtc::ByteBufferReader* buf) override;
+  bool Write(rtc::ByteBufferWriter* buf) const override;
+
+ private:
+  void SetBytes(char* bytes, size_t length);
+
+  char* bytes_;
+};
+
+// Implements STUN attributes that record an error code.
+class StunErrorCodeAttribute : public StunAttribute {
+ public:
+  static const uint16_t MIN_SIZE;
+  StunErrorCodeAttribute(uint16_t type, int code, const std::string& reason);
+  StunErrorCodeAttribute(uint16_t type, uint16_t length);
+  ~StunErrorCodeAttribute() override;
+
+  StunAttributeValueType value_type() const override;
+
+  // The combined error and class, e.g. 0x400.
+  int code() const;
+  void SetCode(int code);
+
+  // The individual error components.
+  int eclass() const { return class_; }
+  int number() const { return number_; }
+  const std::string& reason() const { return reason_; }
+  void SetClass(uint8_t eclass) { class_ = eclass; }
+  void SetNumber(uint8_t number) { number_ = number; }
+  void SetReason(const std::string& reason);
+
+  bool Read(rtc::ByteBufferReader* buf) override;
+  bool Write(rtc::ByteBufferWriter* buf) const override;
+
+ private:
+  uint8_t class_;
+  uint8_t number_;
+  std::string reason_;
+};
+
+// Implements STUN attributes that record a list of attribute names.
+class StunUInt16ListAttribute : public StunAttribute {
+ public:
+  StunUInt16ListAttribute(uint16_t type, uint16_t length);
+  ~StunUInt16ListAttribute() override;
+
+  StunAttributeValueType value_type() const override;
+
+  size_t Size() const;
+  uint16_t GetType(int index) const;
+  void SetType(int index, uint16_t value);
+  void AddType(uint16_t value);
+  void AddTypeAtIndex(uint16_t index, uint16_t value);
+
+  bool Read(rtc::ByteBufferReader* buf) override;
+  bool Write(rtc::ByteBufferWriter* buf) const override;
+
+ private:
+  std::vector<uint16_t>* attr_types_;
+};
+
+// Return a string e.g "STUN BINDING request".
+std::string StunMethodToString(int msg_type);
+
+// Returns the (successful) response type for the given request type.
+// Returns -1 if `request_type` is not a valid request type.
+int GetStunSuccessResponseType(int request_type);
+
+// Returns the error response type for the given request type.
+// Returns -1 if `request_type` is not a valid request type.
+int GetStunErrorResponseType(int request_type);
+
+// Returns whether a given message is a request type.
+bool IsStunRequestType(int msg_type);
+
+// Returns whether a given message is an indication type.
+bool IsStunIndicationType(int msg_type);
+
+// Returns whether a given response is a success type.
+bool IsStunSuccessResponseType(int msg_type);
+
+// Returns whether a given response is an error type.
+bool IsStunErrorResponseType(int msg_type);
+
+// Computes the STUN long-term credential hash.
+bool ComputeStunCredentialHash(const std::string& username,
+                               const std::string& realm,
+                               const std::string& password,
+                               std::string* hash);
+
+// Make a copy af `attribute` and return a new StunAttribute.
+//   This is useful if you don't care about what kind of attribute you
+//   are handling.
+//
+// The implementation copies by calling Write() followed by Read().
+//
+// If `tmp_buffer` is supplied this buffer will be used, otherwise
+// a buffer will created in the method.
+std::unique_ptr<StunAttribute> CopyStunAttribute(
+    const StunAttribute& attribute,
+    rtc::ByteBufferWriter* tmp_buffer_ptr = 0);
+
+// TODO(?): Move the TURN/ICE stuff below out to separate files.
+extern const char TURN_MAGIC_COOKIE_VALUE[4];
+
+// "GTURN" STUN methods.
+// TODO(?): Rename these methods to GTURN_ to make it clear they aren't
+// part of standard STUN/TURN.
+enum RelayMessageType {
+  // For now, using the same defs from TurnMessageType below.
+  // STUN_ALLOCATE_REQUEST              = 0x0003,
+  // STUN_ALLOCATE_RESPONSE             = 0x0103,
+  // STUN_ALLOCATE_ERROR_RESPONSE       = 0x0113,
+  STUN_SEND_REQUEST = 0x0004,
+  STUN_SEND_RESPONSE = 0x0104,
+  STUN_SEND_ERROR_RESPONSE = 0x0114,
+  STUN_DATA_INDICATION = 0x0115,
+};
+
+// "GTURN"-specific STUN attributes.
+// TODO(?): Rename these attributes to GTURN_ to avoid conflicts.
+enum RelayAttributeType {
+  STUN_ATTR_LIFETIME = 0x000d,             // UInt32
+  STUN_ATTR_MAGIC_COOKIE = 0x000f,         // ByteString, 4 bytes
+  STUN_ATTR_BANDWIDTH = 0x0010,            // UInt32
+  STUN_ATTR_DESTINATION_ADDRESS = 0x0011,  // Address
+  STUN_ATTR_SOURCE_ADDRESS2 = 0x0012,      // Address
+  STUN_ATTR_DATA = 0x0013,                 // ByteString
+  STUN_ATTR_OPTIONS = 0x8001,              // UInt32
+};
+
+// A "GTURN" STUN message.
+class RelayMessage : public StunMessage {
+ public:
+  using StunMessage::StunMessage;
+
+ protected:
+  StunAttributeValueType GetAttributeValueType(int type) const override;
+  StunMessage* CreateNew() const override;
+};
+
+// Defined in TURN RFC 5766.
+enum TurnMessageType : uint16_t {
+  STUN_ALLOCATE_REQUEST = 0x0003,
+  STUN_ALLOCATE_RESPONSE = 0x0103,
+  STUN_ALLOCATE_ERROR_RESPONSE = 0x0113,
+  TURN_REFRESH_REQUEST = 0x0004,
+  TURN_REFRESH_RESPONSE = 0x0104,
+  TURN_REFRESH_ERROR_RESPONSE = 0x0114,
+  TURN_SEND_INDICATION = 0x0016,
+  TURN_DATA_INDICATION = 0x0017,
+  TURN_CREATE_PERMISSION_REQUEST = 0x0008,
+  TURN_CREATE_PERMISSION_RESPONSE = 0x0108,
+  TURN_CREATE_PERMISSION_ERROR_RESPONSE = 0x0118,
+  TURN_CHANNEL_BIND_REQUEST = 0x0009,
+  TURN_CHANNEL_BIND_RESPONSE = 0x0109,
+  TURN_CHANNEL_BIND_ERROR_RESPONSE = 0x0119,
+};
+
+enum TurnAttributeType {
+  STUN_ATTR_CHANNEL_NUMBER = 0x000C,    // UInt32
+  STUN_ATTR_TURN_LIFETIME = 0x000d,     // UInt32
+  STUN_ATTR_XOR_PEER_ADDRESS = 0x0012,  // XorAddress
+  // TODO(mallinath) - Uncomment after RelayAttributes are renamed.
+  // STUN_ATTR_DATA                     = 0x0013,  // ByteString
+  STUN_ATTR_XOR_RELAYED_ADDRESS = 0x0016,  // XorAddress
+  STUN_ATTR_EVEN_PORT = 0x0018,            // ByteString, 1 byte.
+  STUN_ATTR_REQUESTED_TRANSPORT = 0x0019,  // UInt32
+  STUN_ATTR_DONT_FRAGMENT = 0x001A,        // No content, Length = 0
+  STUN_ATTR_RESERVATION_TOKEN = 0x0022,    // ByteString, 8 bytes.
+  // TODO(mallinath) - Rename STUN_ATTR_TURN_LIFETIME to STUN_ATTR_LIFETIME and
+  // STUN_ATTR_TURN_DATA to STUN_ATTR_DATA. Also rename RelayMessage attributes
+  // by appending G to attribute name.
+};
+
+// RFC 5766-defined errors.
+enum TurnErrorType {
+  STUN_ERROR_FORBIDDEN = 403,
+  STUN_ERROR_ALLOCATION_MISMATCH = 437,
+  STUN_ERROR_WRONG_CREDENTIALS = 441,
+  STUN_ERROR_UNSUPPORTED_PROTOCOL = 442
+};
+
+extern const int SERVER_NOT_REACHABLE_ERROR;
+
+extern const char STUN_ERROR_REASON_FORBIDDEN[];
+extern const char STUN_ERROR_REASON_ALLOCATION_MISMATCH[];
+extern const char STUN_ERROR_REASON_WRONG_CREDENTIALS[];
+extern const char STUN_ERROR_REASON_UNSUPPORTED_PROTOCOL[];
+class TurnMessage : public StunMessage {
+ public:
+  using StunMessage::StunMessage;
+
+ protected:
+  StunAttributeValueType GetAttributeValueType(int type) const override;
+  StunMessage* CreateNew() const override;
+};
+
+enum IceAttributeType {
+  // RFC 5245 ICE STUN attributes.
+  STUN_ATTR_PRIORITY = 0x0024,         // UInt32
+  STUN_ATTR_USE_CANDIDATE = 0x0025,    // No content, Length = 0
+  STUN_ATTR_ICE_CONTROLLED = 0x8029,   // UInt64
+  STUN_ATTR_ICE_CONTROLLING = 0x802A,  // UInt64
+  // The following attributes are in the comprehension-optional range
+  // (0xC000-0xFFFF) and are not registered with IANA. These STUN attributes are
+  // intended for ICE and should NOT be used in generic use cases of STUN
+  // messages.
+  //
+  // Note that the value 0xC001 has already been assigned by IANA to
+  // ENF-FLOW-DESCRIPTION
+  // (https://www.iana.org/assignments/stun-parameters/stun-parameters.xml).
+  STUN_ATTR_NOMINATION = 0xC001,  // UInt32
+  // UInt32. The higher 16 bits are the network ID. The lower 16 bits are the
+  // network cost.
+  STUN_ATTR_GOOG_NETWORK_INFO = 0xC057,
+  // Experimental: Transaction ID of the last connectivity check received.
+  STUN_ATTR_GOOG_LAST_ICE_CHECK_RECEIVED = 0xC058,
+  // Uint16List. Miscellaneous attributes for future extension.
+  STUN_ATTR_GOOG_MISC_INFO = 0xC059,
+  // Obsolete.
+  STUN_ATTR_GOOG_OBSOLETE_1 = 0xC05A,
+  STUN_ATTR_GOOG_CONNECTION_ID = 0xC05B,  // Not yet implemented.
+  STUN_ATTR_GOOG_DELTA = 0xC05C,          // Not yet implemented.
+  STUN_ATTR_GOOG_DELTA_ACK = 0xC05D,      // Not yet implemented.
+  // MESSAGE-INTEGRITY truncated to 32-bit.
+  STUN_ATTR_GOOG_MESSAGE_INTEGRITY_32 = 0xC060,
+};
+
+// When adding new attributes to STUN_ATTR_GOOG_MISC_INFO
+// (which is a list of uint16_t), append the indices of these attributes below
+// and do NOT change the existing indices. The indices of attributes must be
+// consistent with those used in ConnectionRequest::Prepare when forming a STUN
+// message for the ICE connectivity check, and they are used when parsing a
+// received STUN message.
+enum class IceGoogMiscInfoBindingRequestAttributeIndex {
+  SUPPORT_GOOG_PING_VERSION = 0,
+};
+
+enum class IceGoogMiscInfoBindingResponseAttributeIndex {
+  SUPPORT_GOOG_PING_VERSION = 0,
+};
+
+// RFC 5245-defined errors.
+enum IceErrorCode {
+  STUN_ERROR_ROLE_CONFLICT = 487,
+};
+extern const char STUN_ERROR_REASON_ROLE_CONFLICT[];
+
+// A RFC 5245 ICE STUN message.
+class IceMessage : public StunMessage {
+ public:
+  using StunMessage::StunMessage;
+
+ protected:
+  StunAttributeValueType GetAttributeValueType(int type) const override;
+  StunMessage* CreateNew() const override;
+};
+
+}  // namespace cricket
+
+#endif  // API_TRANSPORT_STUN_H_