#define MS_CLASS "RTC::StunPacket" // #define MS_LOG_DEV_LEVEL 3 #include "StunPacket.hpp" #include // std::snprintf() #include // std::memcmp(), std::memcpy() namespace RTC { static const uint32_t crc32Table[] = { 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d }; inline uint32_t GetCRC32(const uint8_t *data, size_t size) { uint32_t crc{0xFFFFFFFF}; const uint8_t *p = data; while (size--) { crc = crc32Table[(crc ^ *p++) & 0xFF] ^ (crc >> 8); } return crc ^ ~0U; } static std::string openssl_HMACsha1(const void *key, size_t key_len, const void *data, size_t data_len){ std::string str; str.resize(20); unsigned int out_len; #if defined(OPENSSL_VERSION_NUMBER) && (OPENSSL_VERSION_NUMBER > 0x10100000L) //openssl 1.1.0新增api，老版本api作废 HMAC_CTX *ctx = HMAC_CTX_new(); HMAC_CTX_reset(ctx); HMAC_Init_ex(ctx, key, (int)key_len, EVP_sha1(), NULL); HMAC_Update(ctx, (unsigned char*)data, data_len); HMAC_Final(ctx, (unsigned char *)str.data(), &out_len); HMAC_CTX_reset(ctx); HMAC_CTX_free(ctx); #else HMAC_CTX ctx; HMAC_CTX_init(&ctx); HMAC_Init_ex(&ctx, key, key_len, EVP_sha1(), NULL); HMAC_Update(&ctx, (unsigned char*)data, data_len); HMAC_Final(&ctx, (unsigned char *)str.data(), &out_len); HMAC_CTX_cleanup(&ctx); #endif //defined(OPENSSL_VERSION_NUMBER) && (OPENSSL_VERSION_NUMBER > 0x10100000L) return str; } /* Class variables. */ const uint8_t StunPacket::magicCookie[] = { 0x21, 0x12, 0xA4, 0x42 }; /* Class methods. */ StunPacket* StunPacket::Parse(const uint8_t* data, size_t len) { MS_TRACE(); if (!StunPacket::IsStun(data, len)) return nullptr; /* The message type field is decomposed further into the following structure: 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +--+--+-+-+-+-+-+-+-+-+-+-+-+-+ |M |M |M|M|M|C|M|M|M|C|M|M|M|M| |11|10|9|8|7|1|6|5|4|0|3|2|1|0| +--+--+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: Format of STUN Message Type Field Here the bits in the message type field are shown as most significant (M11) through least significant (M0). M11 through M0 represent a 12- bit encoding of the method. C1 and C0 represent a 2-bit encoding of the class. */ // Get type field. uint16_t msgType = Utils::Byte::Get2Bytes(data, 0); // Get length field. uint16_t msgLength = Utils::Byte::Get2Bytes(data, 2); // length field must be total size minus header's 20 bytes, and must be multiple of 4 Bytes. if ((static_cast(msgLength) != len - 20) || ((msgLength & 0x03) != 0)) { MS_WARN_TAG( ice, "length field + 20 does not match total size (or it is not multiple of 4 bytes), " "packet discarded"); return nullptr; } // Get STUN method. uint16_t msgMethod = (msgType & 0x000f) | ((msgType & 0x00e0) >> 1) | ((msgType & 0x3E00) >> 2); // Get STUN class. uint16_t msgClass = ((data[0] & 0x01) << 1) | ((data[1] & 0x10) >> 4); // Create a new StunPacket (data + 8 points to the received TransactionID field). auto* packet = new StunPacket( static_cast(msgClass), static_cast(msgMethod), data + 8, data, len); /* STUN Attributes After the STUN header are zero or more attributes. Each attribute MUST be TLV encoded, with a 16-bit type, 16-bit length, and value. Each STUN attribute MUST end on a 32-bit boundary. As mentioned above, all fields in an attribute are transmitted most significant bit first. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Value (variable) .... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ // Start looking for attributes after STUN header (Byte #20). size_t pos{ 20 }; // Flags (positions) for special MESSAGE-INTEGRITY and FINGERPRINT attributes. bool hasMessageIntegrity{ false }; bool hasFingerprint{ false }; size_t fingerprintAttrPos; // Will point to the beginning of the attribute. uint32_t fingerprint; // Holds the value of the FINGERPRINT attribute. // Ensure there are at least 4 remaining bytes (attribute with 0 length). while (pos + 4 <= len) { // Get the attribute type. auto attrType = static_cast(Utils::Byte::Get2Bytes(data, pos)); // Get the attribute length. uint16_t attrLength = Utils::Byte::Get2Bytes(data, pos + 2); // Ensure the attribute length is not greater than the remaining size. if ((pos + 4 + attrLength) > len) { MS_WARN_TAG(ice, "the attribute length exceeds the remaining size, packet discarded"); delete packet; return nullptr; } // FINGERPRINT must be the last attribute. if (hasFingerprint) { MS_WARN_TAG(ice, "attribute after FINGERPRINT is not allowed, packet discarded"); delete packet; return nullptr; } // After a MESSAGE-INTEGRITY attribute just FINGERPRINT is allowed. if (hasMessageIntegrity && attrType != Attribute::FINGERPRINT) { MS_WARN_TAG( ice, "attribute after MESSAGE-INTEGRITY other than FINGERPRINT is not allowed, " "packet discarded"); delete packet; return nullptr; } const uint8_t* attrValuePos = data + pos + 4; switch (attrType) { case Attribute::USERNAME: { packet->SetUsername( reinterpret_cast(attrValuePos), static_cast(attrLength)); break; } case Attribute::PRIORITY: { // Ensure attribute length is 4 bytes. if (attrLength != 4) { MS_WARN_TAG(ice, "attribute PRIORITY must be 4 bytes length, packet discarded"); delete packet; return nullptr; } packet->SetPriority(Utils::Byte::Get4Bytes(attrValuePos, 0)); break; } case Attribute::ICE_CONTROLLING: { // Ensure attribute length is 8 bytes. if (attrLength != 8) { MS_WARN_TAG(ice, "attribute ICE-CONTROLLING must be 8 bytes length, packet discarded"); delete packet; return nullptr; } packet->SetIceControlling(Utils::Byte::Get8Bytes(attrValuePos, 0)); break; } case Attribute::ICE_CONTROLLED: { // Ensure attribute length is 8 bytes. if (attrLength != 8) { MS_WARN_TAG(ice, "attribute ICE-CONTROLLED must be 8 bytes length, packet discarded"); delete packet; return nullptr; } packet->SetIceControlled(Utils::Byte::Get8Bytes(attrValuePos, 0)); break; } case Attribute::USE_CANDIDATE: { // Ensure attribute length is 0 bytes. if (attrLength != 0) { MS_WARN_TAG(ice, "attribute USE-CANDIDATE must be 0 bytes length, packet discarded"); delete packet; return nullptr; } packet->SetUseCandidate(); break; } case Attribute::MESSAGE_INTEGRITY: { // Ensure attribute length is 20 bytes. if (attrLength != 20) { MS_WARN_TAG(ice, "attribute MESSAGE-INTEGRITY must be 20 bytes length, packet discarded"); delete packet; return nullptr; } hasMessageIntegrity = true; packet->SetMessageIntegrity(attrValuePos); break; } case Attribute::FINGERPRINT: { // Ensure attribute length is 4 bytes. if (attrLength != 4) { MS_WARN_TAG(ice, "attribute FINGERPRINT must be 4 bytes length, packet discarded"); delete packet; return nullptr; } hasFingerprint = true; fingerprintAttrPos = pos; fingerprint = Utils::Byte::Get4Bytes(attrValuePos, 0); packet->SetFingerprint(); break; } case Attribute::ERROR_CODE: { // Ensure attribute length >= 4bytes. if (attrLength < 4) { MS_WARN_TAG(ice, "attribute ERROR-CODE must be >= 4bytes length, packet discarded"); delete packet; return nullptr; } uint8_t errorClass = Utils::Byte::Get1Byte(attrValuePos, 2); uint8_t errorNumber = Utils::Byte::Get1Byte(attrValuePos, 3); auto errorCode = static_cast(errorClass * 100 + errorNumber); packet->SetErrorCode(errorCode); break; } default:; } // Set next attribute position. pos = static_cast(Utils::Byte::PadTo4Bytes(static_cast(pos + 4 + attrLength))); } // Ensure current position matches the total length. if (pos != len) { MS_WARN_TAG(ice, "computed packet size does not match total size, packet discarded"); delete packet; return nullptr; } // If it has FINGERPRINT attribute then verify it. if (hasFingerprint) { // Compute the CRC32 of the received packet up to (but excluding) the // FINGERPRINT attribute and XOR it with 0x5354554e. uint32_t computedFingerprint = GetCRC32(data, fingerprintAttrPos) ^ 0x5354554e; // Compare with the FINGERPRINT value in the packet. if (fingerprint != computedFingerprint) { MS_WARN_TAG( ice, "computed FINGERPRINT value does not match the value in the packet, " "packet discarded"); delete packet; return nullptr; } } return packet; } /* Instance methods. */ StunPacket::StunPacket( Class klass, Method method, const uint8_t* transactionId, const uint8_t* data, size_t size) : klass(klass), method(method), transactionId(transactionId), data(const_cast(data)), size(size) { MS_TRACE(); } StunPacket::~StunPacket() { MS_TRACE(); } #if 0 void StunPacket::Dump() const { MS_TRACE(); MS_DUMP(""); std::string klass; switch (this->klass) { case Class::REQUEST: klass = "Request"; break; case Class::INDICATION: klass = "Indication"; break; case Class::SUCCESS_RESPONSE: klass = "SuccessResponse"; break; case Class::ERROR_RESPONSE: klass = "ErrorResponse"; break; } if (this->method == Method::BINDING) { MS_DUMP(" Binding %s", klass.c_str()); } else { // This prints the unknown method number. Example: TURN Allocate => 0x003. MS_DUMP(" %s with unknown method %#.3x", klass.c_str(), static_cast(this->method)); } MS_DUMP(" size: %zu bytes", this->size); static char transactionId[25]; for (int i{ 0 }; i < 12; ++i) { // NOTE: n must be 3 because snprintf adds a \0 after printed chars. std::snprintf(transactionId + (i * 2), 3, "%.2x", this->transactionId[i]); } MS_DUMP(" transactionId: %s", transactionId); if (this->errorCode != 0u) MS_DUMP(" errorCode: %" PRIu16, this->errorCode); if (!this->username.empty()) MS_DUMP(" username: %s", this->username.c_str()); if (this->priority != 0u) MS_DUMP(" priority: %" PRIu32, this->priority); if (this->iceControlling != 0u) MS_DUMP(" iceControlling: %" PRIu64, this->iceControlling); if (this->iceControlled != 0u) MS_DUMP(" iceControlled: %" PRIu64, this->iceControlled); if (this->hasUseCandidate) MS_DUMP(" useCandidate"); if (this->xorMappedAddress != nullptr) { int family; uint16_t port; std::string ip; Utils::IP::GetAddressInfo(this->xorMappedAddress, family, ip, port); MS_DUMP(" xorMappedAddress: %s : %" PRIu16, ip.c_str(), port); } if (this->messageIntegrity != nullptr) { static char messageIntegrity[41]; for (int i{ 0 }; i < 20; ++i) { std::snprintf(messageIntegrity + (i * 2), 3, "%.2x", this->messageIntegrity[i]); } MS_DUMP(" messageIntegrity: %s", messageIntegrity); } if (this->hasFingerprint) MS_DUMP(" has fingerprint"); MS_DUMP(""); } #endif StunPacket::Authentication StunPacket::CheckAuthentication( const std::string& localUsername, const std::string& localPassword) { MS_TRACE(); switch (this->klass) { case Class::REQUEST: case Class::INDICATION: { // Both USERNAME and MESSAGE-INTEGRITY must be present. if (!this->messageIntegrity || this->username.empty()) return Authentication::BAD_REQUEST; // Check that USERNAME attribute begins with our local username plus ":". size_t localUsernameLen = localUsername.length(); if ( this->username.length() <= localUsernameLen || this->username.at(localUsernameLen) != ':' || (this->username.compare(0, localUsernameLen, localUsername) != 0)) { return Authentication::UNAUTHORIZED; } break; } // This method cannot check authentication in received responses (as we // are ICE-Lite and don't generate requests). case Class::SUCCESS_RESPONSE: case Class::ERROR_RESPONSE: { MS_ERROR("cannot check authentication for a STUN response"); return Authentication::BAD_REQUEST; } } // If there is FINGERPRINT it must be discarded for MESSAGE-INTEGRITY calculation, // so the header length field must be modified (and later restored). if (this->hasFingerprint) // Set the header length field: full size - header length (20) - FINGERPRINT length (8). Utils::Byte::Set2Bytes(this->data, 2, static_cast(this->size - 20 - 8)); // Calculate the HMAC-SHA1 of the message according to MESSAGE-INTEGRITY rules. auto computedMessageIntegrity = openssl_HMACsha1( localPassword.data(),localPassword.size(), this->data, (this->messageIntegrity - 4) - this->data); Authentication result; // Compare the computed HMAC-SHA1 with the MESSAGE-INTEGRITY in the packet. if (std::memcmp(this->messageIntegrity, computedMessageIntegrity.data(), computedMessageIntegrity.size()) == 0) result = Authentication::OK; else result = Authentication::UNAUTHORIZED; // Restore the header length field. if (this->hasFingerprint) Utils::Byte::Set2Bytes(this->data, 2, static_cast(this->size - 20)); return result; } StunPacket* StunPacket::CreateSuccessResponse() { MS_TRACE(); MS_ASSERT( this->klass == Class::REQUEST, "attempt to create a success response for a non Request STUN packet"); return new StunPacket(Class::SUCCESS_RESPONSE, this->method, this->transactionId, nullptr, 0); } StunPacket* StunPacket::CreateErrorResponse(uint16_t errorCode) { MS_TRACE(); MS_ASSERT( this->klass == Class::REQUEST, "attempt to create an error response for a non Request STUN packet"); auto* response = new StunPacket(Class::ERROR_RESPONSE, this->method, this->transactionId, nullptr, 0); response->SetErrorCode(errorCode); return response; } void StunPacket::Authenticate(const std::string& password) { // Just for Request, Indication and SuccessResponse messages. if (this->klass == Class::ERROR_RESPONSE) { MS_ERROR("cannot set password for ErrorResponse messages"); return; } this->password = password; } void StunPacket::Serialize(uint8_t* buffer) { MS_TRACE(); // Some useful variables. uint16_t usernamePaddedLen{ 0 }; uint16_t xorMappedAddressPaddedLen{ 0 }; bool addXorMappedAddress = ((this->xorMappedAddress != nullptr) && this->method == StunPacket::Method::BINDING && this->klass == Class::SUCCESS_RESPONSE); bool addErrorCode = ((this->errorCode != 0u) && this->klass == Class::ERROR_RESPONSE); bool addMessageIntegrity = (this->klass != Class::ERROR_RESPONSE && !this->password.empty()); bool addFingerprint{ true }; // Do always. // Update data pointer. this->data = buffer; // First calculate the total required size for the entire packet. this->size = 20; // Header. if (!this->username.empty()) { usernamePaddedLen = Utils::Byte::PadTo4Bytes(static_cast(this->username.length())); this->size += 4 + usernamePaddedLen; } if (this->priority != 0u) this->size += 4 + 4; if (this->iceControlling != 0u) this->size += 4 + 8; if (this->iceControlled != 0u) this->size += 4 + 8; if (this->hasUseCandidate) this->size += 4; if (addXorMappedAddress) { switch (this->xorMappedAddress->sa_family) { case AF_INET: { xorMappedAddressPaddedLen = 8; this->size += 4 + 8; break; } case AF_INET6: { xorMappedAddressPaddedLen = 20; this->size += 4 + 20; break; } default: { MS_ERROR("invalid inet family in XOR-MAPPED-ADDRESS attribute"); addXorMappedAddress = false; } } } if (addErrorCode) this->size += 4 + 4; if (addMessageIntegrity) this->size += 4 + 20; if (addFingerprint) this->size += 4 + 4; // Merge class and method fields into type. uint16_t typeField = (static_cast(this->method) & 0x0f80) << 2; typeField |= (static_cast(this->method) & 0x0070) << 1; typeField |= (static_cast(this->method) & 0x000f); typeField |= (static_cast(this->klass) & 0x02) << 7; typeField |= (static_cast(this->klass) & 0x01) << 4; // Set type field. Utils::Byte::Set2Bytes(buffer, 0, typeField); // Set length field. Utils::Byte::Set2Bytes(buffer, 2, static_cast(this->size) - 20); // Set magic cookie. std::memcpy(buffer + 4, StunPacket::magicCookie, 4); // Set TransactionId field. std::memcpy(buffer + 8, this->transactionId, 12); // Update the transaction ID pointer. this->transactionId = buffer + 8; // Add atributes. size_t pos{ 20 }; // Add USERNAME. if (usernamePaddedLen != 0u) { Utils::Byte::Set2Bytes(buffer, pos, static_cast(Attribute::USERNAME)); Utils::Byte::Set2Bytes(buffer, pos + 2, static_cast(this->username.length())); std::memcpy(buffer + pos + 4, this->username.c_str(), this->username.length()); pos += 4 + usernamePaddedLen; } // Add PRIORITY. if (this->priority != 0u) { Utils::Byte::Set2Bytes(buffer, pos, static_cast(Attribute::PRIORITY)); Utils::Byte::Set2Bytes(buffer, pos + 2, 4); Utils::Byte::Set4Bytes(buffer, pos + 4, this->priority); pos += 4 + 4; } // Add ICE-CONTROLLING. if (this->iceControlling != 0u) { Utils::Byte::Set2Bytes(buffer, pos, static_cast(Attribute::ICE_CONTROLLING)); Utils::Byte::Set2Bytes(buffer, pos + 2, 8); Utils::Byte::Set8Bytes(buffer, pos + 4, this->iceControlling); pos += 4 + 8; } // Add ICE-CONTROLLED. if (this->iceControlled != 0u) { Utils::Byte::Set2Bytes(buffer, pos, static_cast(Attribute::ICE_CONTROLLED)); Utils::Byte::Set2Bytes(buffer, pos + 2, 8); Utils::Byte::Set8Bytes(buffer, pos + 4, this->iceControlled); pos += 4 + 8; } // Add USE-CANDIDATE. if (this->hasUseCandidate) { Utils::Byte::Set2Bytes(buffer, pos, static_cast(Attribute::USE_CANDIDATE)); Utils::Byte::Set2Bytes(buffer, pos + 2, 0); pos += 4; } // Add XOR-MAPPED-ADDRESS if (addXorMappedAddress) { Utils::Byte::Set2Bytes(buffer, pos, static_cast(Attribute::XOR_MAPPED_ADDRESS)); Utils::Byte::Set2Bytes(buffer, pos + 2, xorMappedAddressPaddedLen); uint8_t* attrValue = buffer + pos + 4; switch (this->xorMappedAddress->sa_family) { case AF_INET: { // Set first byte to 0. attrValue[0] = 0; // Set inet family. attrValue[1] = 0x01; // Set port and XOR it. std::memcpy( attrValue + 2, &(reinterpret_cast(this->xorMappedAddress))->sin_port, 2); attrValue[2] ^= StunPacket::magicCookie[0]; attrValue[3] ^= StunPacket::magicCookie[1]; // Set address and XOR it. std::memcpy( attrValue + 4, &(reinterpret_cast(this->xorMappedAddress))->sin_addr.s_addr, 4); attrValue[4] ^= StunPacket::magicCookie[0]; attrValue[5] ^= StunPacket::magicCookie[1]; attrValue[6] ^= StunPacket::magicCookie[2]; attrValue[7] ^= StunPacket::magicCookie[3]; pos += 4 + 8; break; } case AF_INET6: { // Set first byte to 0. attrValue[0] = 0; // Set inet family. attrValue[1] = 0x02; // Set port and XOR it. std::memcpy( attrValue + 2, &(reinterpret_cast(this->xorMappedAddress))->sin6_port, 2); attrValue[2] ^= StunPacket::magicCookie[0]; attrValue[3] ^= StunPacket::magicCookie[1]; // Set address and XOR it. std::memcpy( attrValue + 4, &(reinterpret_cast(this->xorMappedAddress))->sin6_addr.s6_addr, 16); attrValue[4] ^= StunPacket::magicCookie[0]; attrValue[5] ^= StunPacket::magicCookie[1]; attrValue[6] ^= StunPacket::magicCookie[2]; attrValue[7] ^= StunPacket::magicCookie[3]; attrValue[8] ^= this->transactionId[0]; attrValue[9] ^= this->transactionId[1]; attrValue[10] ^= this->transactionId[2]; attrValue[11] ^= this->transactionId[3]; attrValue[12] ^= this->transactionId[4]; attrValue[13] ^= this->transactionId[5]; attrValue[14] ^= this->transactionId[6]; attrValue[15] ^= this->transactionId[7]; attrValue[16] ^= this->transactionId[8]; attrValue[17] ^= this->transactionId[9]; attrValue[18] ^= this->transactionId[10]; attrValue[19] ^= this->transactionId[11]; pos += 4 + 20; break; } } } // Add ERROR-CODE. if (addErrorCode) { Utils::Byte::Set2Bytes(buffer, pos, static_cast(Attribute::ERROR_CODE)); Utils::Byte::Set2Bytes(buffer, pos + 2, 4); auto codeClass = static_cast(this->errorCode / 100); uint8_t codeNumber = static_cast(this->errorCode) - (codeClass * 100); Utils::Byte::Set2Bytes(buffer, pos + 4, 0); Utils::Byte::Set1Byte(buffer, pos + 6, codeClass); Utils::Byte::Set1Byte(buffer, pos + 7, codeNumber); pos += 4 + 4; } // Add MESSAGE-INTEGRITY. if (addMessageIntegrity) { // Ignore FINGERPRINT. if (addFingerprint) Utils::Byte::Set2Bytes(buffer, 2, static_cast(this->size - 20 - 8)); // Calculate the HMAC-SHA1 of the packet according to MESSAGE-INTEGRITY rules. auto computedMessageIntegrity = openssl_HMACsha1(this->password.data(), this->password.size(), buffer, pos); Utils::Byte::Set2Bytes(buffer, pos, static_cast(Attribute::MESSAGE_INTEGRITY)); Utils::Byte::Set2Bytes(buffer, pos + 2, 20); std::memcpy(buffer + pos + 4, computedMessageIntegrity.data(), computedMessageIntegrity.size()); // Update the pointer. this->messageIntegrity = buffer + pos + 4; pos += 4 + 20; // Restore length field. if (addFingerprint) Utils::Byte::Set2Bytes(buffer, 2, static_cast(this->size - 20)); } else { // Unset the pointer (if it was set). this->messageIntegrity = nullptr; } // Add FINGERPRINT. if (addFingerprint) { // Compute the CRC32 of the packet up to (but excluding) the FINGERPRINT // attribute and XOR it with 0x5354554e. uint32_t computedFingerprint = GetCRC32(buffer, pos) ^ 0x5354554e; Utils::Byte::Set2Bytes(buffer, pos, static_cast(Attribute::FINGERPRINT)); Utils::Byte::Set2Bytes(buffer, pos + 2, 4); Utils::Byte::Set4Bytes(buffer, pos + 4, computedFingerprint); pos += 4 + 4; // Set flag. this->hasFingerprint = true; } else { this->hasFingerprint = false; } MS_ASSERT(pos == this->size, "pos != this->size"); } } // namespace RTC