Mike J. Chen | 6c92951 | 2011-08-15 11:59:47 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2012 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef ANDROID_COMMON_TIME_SERVER_PACKETS_H |
| 18 | #define ANDROID_COMMON_TIME_SERVER_PACKETS_H |
| 19 | |
| 20 | #include <stdint.h> |
| 21 | #include <common_time/ICommonClock.h> |
| 22 | |
| 23 | namespace android { |
| 24 | |
| 25 | /***** time sync protocol packets *****/ |
| 26 | |
| 27 | enum TimeServicePacketType { |
| 28 | TIME_PACKET_WHO_IS_MASTER_REQUEST = 1, |
| 29 | TIME_PACKET_WHO_IS_MASTER_RESPONSE, |
| 30 | TIME_PACKET_SYNC_REQUEST, |
| 31 | TIME_PACKET_SYNC_RESPONSE, |
| 32 | TIME_PACKET_MASTER_ANNOUNCEMENT, |
| 33 | }; |
| 34 | |
| 35 | class TimeServicePacketHeader { |
| 36 | public: |
| 37 | friend class UniversalTimeServicePacket; |
| 38 | // magic number identifying the protocol |
| 39 | uint32_t magic; |
| 40 | |
| 41 | // protocol version of the packet |
| 42 | uint16_t version; |
| 43 | |
| 44 | // type of the packet |
| 45 | TimeServicePacketType packetType; |
| 46 | |
| 47 | // the timeline ID |
| 48 | uint64_t timelineID; |
| 49 | |
| 50 | // synchronization group this packet belongs to (used to operate multiple |
| 51 | // synchronization domains which all use the same master election endpoint) |
| 52 | uint64_t syncGroupID; |
| 53 | |
| 54 | ssize_t serializePacket(uint8_t* data, uint32_t length); |
| 55 | |
| 56 | protected: |
| 57 | void initHeader(TimeServicePacketType type, |
| 58 | const uint64_t tlID, |
| 59 | const uint64_t groupID) { |
| 60 | magic = kMagic; |
| 61 | version = kCurVersion; |
| 62 | packetType = type; |
| 63 | timelineID = tlID; |
| 64 | syncGroupID = groupID; |
| 65 | } |
| 66 | |
| 67 | bool checkPacket(uint64_t expectedSyncGroupID) const { |
| 68 | return ((magic == kMagic) && |
| 69 | (version == kCurVersion) && |
| 70 | (!expectedSyncGroupID || (syncGroupID == expectedSyncGroupID))); |
| 71 | } |
| 72 | |
| 73 | ssize_t serializeHeader(uint8_t* data, uint32_t length); |
| 74 | ssize_t deserializeHeader(const uint8_t* data, uint32_t length); |
| 75 | |
| 76 | private: |
| 77 | static const uint32_t kMagic; |
| 78 | static const uint16_t kCurVersion; |
| 79 | }; |
| 80 | |
| 81 | // packet querying for a suitable master |
| 82 | class WhoIsMasterRequestPacket : public TimeServicePacketHeader { |
| 83 | public: |
| 84 | uint64_t senderDeviceID; |
| 85 | uint8_t senderDevicePriority; |
| 86 | |
| 87 | void initHeader(const uint64_t groupID) { |
| 88 | TimeServicePacketHeader::initHeader(TIME_PACKET_WHO_IS_MASTER_REQUEST, |
| 89 | ICommonClock::kInvalidTimelineID, |
| 90 | groupID); |
| 91 | } |
| 92 | |
| 93 | ssize_t serializePacket(uint8_t* data, uint32_t length); |
| 94 | ssize_t deserializePacket(const uint8_t* data, uint32_t length); |
| 95 | }; |
| 96 | |
| 97 | // response to a WhoIsMaster request |
| 98 | class WhoIsMasterResponsePacket : public TimeServicePacketHeader { |
| 99 | public: |
| 100 | uint64_t deviceID; |
| 101 | uint8_t devicePriority; |
| 102 | |
| 103 | void initHeader(const uint64_t tlID, const uint64_t groupID) { |
| 104 | TimeServicePacketHeader::initHeader(TIME_PACKET_WHO_IS_MASTER_RESPONSE, |
| 105 | tlID, groupID); |
| 106 | } |
| 107 | |
| 108 | ssize_t serializePacket(uint8_t* data, uint32_t length); |
| 109 | ssize_t deserializePacket(const uint8_t* data, uint32_t length); |
| 110 | }; |
| 111 | |
| 112 | // packet sent by a client requesting correspondence between local |
| 113 | // and common time |
| 114 | class SyncRequestPacket : public TimeServicePacketHeader { |
| 115 | public: |
| 116 | // local time when this request was transmitted |
| 117 | int64_t clientTxLocalTime; |
| 118 | |
| 119 | void initHeader(const uint64_t tlID, const uint64_t groupID) { |
| 120 | TimeServicePacketHeader::initHeader(TIME_PACKET_SYNC_REQUEST, |
| 121 | tlID, groupID); |
| 122 | } |
| 123 | |
| 124 | ssize_t serializePacket(uint8_t* data, uint32_t length); |
| 125 | ssize_t deserializePacket(const uint8_t* data, uint32_t length); |
| 126 | }; |
| 127 | |
| 128 | // response to a sync request sent by the master |
| 129 | class SyncResponsePacket : public TimeServicePacketHeader { |
| 130 | public: |
| 131 | // local time when this request was transmitted by the client |
| 132 | int64_t clientTxLocalTime; |
| 133 | |
| 134 | // common time when the master received the request |
| 135 | int64_t masterRxCommonTime; |
| 136 | |
| 137 | // common time when the master transmitted the response |
| 138 | int64_t masterTxCommonTime; |
| 139 | |
| 140 | // flag that is set if the recipient of the sync request is not acting |
| 141 | // as a master for the requested timeline |
| 142 | uint32_t nak; |
| 143 | |
| 144 | void initHeader(const uint64_t tlID, const uint64_t groupID) { |
| 145 | TimeServicePacketHeader::initHeader(TIME_PACKET_SYNC_RESPONSE, |
| 146 | tlID, groupID); |
| 147 | } |
| 148 | |
| 149 | ssize_t serializePacket(uint8_t* data, uint32_t length); |
| 150 | ssize_t deserializePacket(const uint8_t* data, uint32_t length); |
| 151 | }; |
| 152 | |
| 153 | // announcement of the master's presence |
| 154 | class MasterAnnouncementPacket : public TimeServicePacketHeader { |
| 155 | public: |
| 156 | // the master's device ID |
| 157 | uint64_t deviceID; |
| 158 | uint8_t devicePriority; |
| 159 | |
| 160 | void initHeader(const uint64_t tlID, const uint64_t groupID) { |
| 161 | TimeServicePacketHeader::initHeader(TIME_PACKET_MASTER_ANNOUNCEMENT, |
| 162 | tlID, groupID); |
| 163 | } |
| 164 | |
| 165 | ssize_t serializePacket(uint8_t* data, uint32_t length); |
| 166 | ssize_t deserializePacket(const uint8_t* data, uint32_t length); |
| 167 | }; |
| 168 | |
| 169 | class UniversalTimeServicePacket { |
| 170 | public: |
| 171 | uint16_t packetType; |
| 172 | union { |
| 173 | WhoIsMasterRequestPacket who_is_master_request; |
| 174 | WhoIsMasterResponsePacket who_is_master_response; |
| 175 | SyncRequestPacket sync_request; |
| 176 | SyncResponsePacket sync_response; |
| 177 | MasterAnnouncementPacket master_announcement; |
| 178 | } p; |
| 179 | |
| 180 | ssize_t deserializePacket(const uint8_t* data, |
| 181 | uint32_t length, |
| 182 | uint64_t expectedSyncGroupID); |
| 183 | }; |
| 184 | |
| 185 | }; // namespace android |
| 186 | |
| 187 | #endif // ANDROID_COMMON_TIME_SERVER_PACKETS_H |
| 188 | |
| 189 | |