| // Copyright 2020 Google LLC |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "connections/implementation/wifi_lan_service_info.h" |
| |
| #include <inttypes.h> |
| |
| #include <cstring> |
| #include <utility> |
| |
| #include "absl/strings/str_cat.h" |
| #include "internal/platform/base64_utils.h" |
| #include "internal/platform/base_input_stream.h" |
| #include "internal/platform/logging.h" |
| |
| namespace location { |
| namespace nearby { |
| namespace connections { |
| |
| // These definitions are necessary before C++17. |
| constexpr absl::string_view WifiLanServiceInfo::kKeyEndpointInfo; |
| constexpr std::uint32_t WifiLanServiceInfo::kServiceIdHashLength; |
| constexpr int WifiLanServiceInfo::kMaxEndpointInfoLength; |
| |
| WifiLanServiceInfo::WifiLanServiceInfo(Version version, Pcp pcp, |
| absl::string_view endpoint_id, |
| const ByteArray& service_id_hash, |
| const ByteArray& endpoint_info, |
| const ByteArray& uwb_address, |
| WebRtcState web_rtc_state) { |
| if (version != Version::kV1 || endpoint_id.empty() || |
| endpoint_id.length() != kEndpointIdLength || |
| service_id_hash.size() != kServiceIdHashLength || |
| endpoint_info.size() > kMaxEndpointInfoLength) { |
| return; |
| } |
| switch (pcp) { |
| case Pcp::kP2pCluster: // Fall through |
| case Pcp::kP2pStar: // Fall through |
| case Pcp::kP2pPointToPoint: |
| break; |
| default: |
| return; |
| } |
| |
| version_ = version; |
| pcp_ = pcp; |
| service_id_hash_ = service_id_hash; |
| endpoint_id_ = std::string(endpoint_id); |
| endpoint_info_ = endpoint_info; |
| uwb_address_ = uwb_address; |
| web_rtc_state_ = web_rtc_state; |
| } |
| |
| WifiLanServiceInfo::WifiLanServiceInfo(const NsdServiceInfo& nsd_service_info) { |
| auto txt_endpoint_info_name = |
| nsd_service_info.GetTxtRecord(std::string(kKeyEndpointInfo)); |
| if (!txt_endpoint_info_name.empty()) { |
| endpoint_info_ = Base64Utils::Decode(txt_endpoint_info_name); |
| if (endpoint_info_.size() > kMaxEndpointInfoLength) { |
| NEARBY_LOG(INFO, |
| "Cannot deserialize EndpointInfo: expecting endpoint info " |
| "max %d raw bytes, got %" PRIu64, |
| kMaxEndpointInfoLength, endpoint_info_.size()); |
| return; |
| } |
| } |
| |
| auto service_info_name = nsd_service_info.GetServiceName(); |
| ByteArray service_info_bytes = Base64Utils::Decode(service_info_name); |
| if (service_info_bytes.Empty()) { |
| NEARBY_LOG( |
| INFO, |
| "Cannot deserialize WifiLanServiceInfo: failed Base64 decoding of %s", |
| std::string(service_info_name).c_str()); |
| return; |
| } |
| |
| if (service_info_bytes.size() < kMinLanServiceNameLength) { |
| NEARBY_LOG(INFO, |
| "Cannot deserialize WifiLanServiceInfo: expecting min %d raw " |
| "bytes, got %" PRIu64, |
| kMinLanServiceNameLength, service_info_bytes.size()); |
| return; |
| } |
| |
| BaseInputStream base_input_stream{service_info_bytes}; |
| // The first 1 byte is supposed to be the version and pcp. |
| auto version_and_pcp_byte = static_cast<char>(base_input_stream.ReadUint8()); |
| // The upper 3 bits are supposed to be the version. |
| version_ = |
| static_cast<Version>((version_and_pcp_byte & kVersionBitmask) >> 5); |
| if (version_ != Version::kV1) { |
| NEARBY_LOG(INFO, |
| "Cannot deserialize WifiLanServiceInfo: unsupported Version %d", |
| version_); |
| return; |
| } |
| // The lower 5 bits are supposed to be the Pcp. |
| pcp_ = static_cast<Pcp>(version_and_pcp_byte & kPcpBitmask); |
| switch (pcp_) { |
| case Pcp::kP2pCluster: // Fall through |
| case Pcp::kP2pStar: // Fall through |
| case Pcp::kP2pPointToPoint: |
| break; |
| default: |
| NEARBY_LOG(INFO, |
| "Cannot deserialize WifiLanServiceInfo: unsupported V1 PCP %d", |
| pcp_); |
| } |
| |
| // The next 4 bytes are supposed to be the endpoint_id. |
| endpoint_id_ = std::string{base_input_stream.ReadBytes(kEndpointIdLength)}; |
| |
| // The next 3 bytes are supposed to be the service_id_hash. |
| service_id_hash_ = base_input_stream.ReadBytes(kServiceIdHashLength); |
| |
| // The next 1 byte is supposed to be the length of the uwb_address. If |
| // available, continues to deserialize UWB address and extra field of WebRtc |
| // state. |
| if (base_input_stream.IsAvailable(1)) { |
| std::uint32_t expected_uwb_address_length = base_input_stream.ReadUint8(); |
| // If the length of uwb_address is not zero, then retrieve it. |
| if (expected_uwb_address_length != 0) { |
| uwb_address_ = base_input_stream.ReadBytes(expected_uwb_address_length); |
| if (uwb_address_.Empty() || |
| uwb_address_.size() != expected_uwb_address_length) { |
| NEARBY_LOG(INFO, |
| "Cannot deserialize WifiLanServiceInfo: expected " |
| "uwbAddress size to be %d bytes, got %" PRIu64, |
| expected_uwb_address_length, uwb_address_.size()); |
| // Clear enpoint_id for validity. |
| endpoint_id_.clear(); |
| return; |
| } |
| } |
| |
| // The next 1 byte is extra field. |
| web_rtc_state_ = WebRtcState::kUndefined; |
| if (base_input_stream.IsAvailable(kExtraFieldLength)) { |
| auto extra_field = static_cast<char>(base_input_stream.ReadUint8()); |
| web_rtc_state_ = (extra_field & kWebRtcConnectableFlagBitmask) == 1 |
| ? WebRtcState::kConnectable |
| : WebRtcState::kUnconnectable; |
| } |
| } |
| } |
| |
| WifiLanServiceInfo::operator NsdServiceInfo() const { |
| if (!IsValid()) { |
| return {}; |
| } |
| |
| // The upper 3 bits are the Version. |
| auto version_and_pcp_byte = static_cast<char>( |
| (static_cast<uint32_t>(Version::kV1) << 5) & kVersionBitmask); |
| // The lower 5 bits are the PCP. |
| version_and_pcp_byte |= |
| static_cast<char>(static_cast<uint32_t>(pcp_) & kPcpBitmask); |
| |
| std::string out = absl::StrCat(std::string(1, version_and_pcp_byte), |
| endpoint_id_, std::string(service_id_hash_)); |
| |
| // The next bytes are UWB address field. |
| if (!uwb_address_.Empty()) { |
| absl::StrAppend(&out, std::string(1, uwb_address_.size())); |
| absl::StrAppend(&out, std::string(uwb_address_)); |
| } else { |
| // Write UWB address with length 0 to be able to read the next field, which |
| // needs to be appended. |
| if (web_rtc_state_ != WebRtcState::kUndefined) |
| absl::StrAppend(&out, std::string(1, uwb_address_.size())); |
| } |
| |
| // The next 1 byte is extra field. |
| if (web_rtc_state_ != WebRtcState::kUndefined) { |
| int web_rtc_connectable_flag = |
| (web_rtc_state_ == WebRtcState::kConnectable) ? 1 : 0; |
| char field_byte = static_cast<char>(web_rtc_connectable_flag) & |
| kWebRtcConnectableFlagBitmask; |
| absl::StrAppend(&out, std::string(1, field_byte)); |
| } |
| |
| NsdServiceInfo nsd_service_info; |
| nsd_service_info.SetServiceName( |
| Base64Utils::Encode(ByteArray{std::move(out)})); |
| nsd_service_info.SetTxtRecord(std::string(kKeyEndpointInfo), |
| Base64Utils::Encode(endpoint_info_)); |
| return nsd_service_info; |
| } |
| |
| } // namespace connections |
| } // namespace nearby |
| } // namespace location |