| 119 | } |
| 120 | |
| 121 | void NtpClient::onReceive(pbuf* buf, [[maybe_unused]] IpAddress remoteIP, [[maybe_unused]] uint16_t remotePort) |
| 122 | { |
| 123 | debug_d("NtpClient::onReceive(%s:%u)", remoteIP.toString().c_str(), remotePort); |
| 124 | |
| 125 | stopTimer(); |
| 126 | auto retry = [this]() { startTimer(NTP_RESPONSE_TIMEOUT_MS); }; |
| 127 | |
| 128 | // We do some basic check to see if it really is a ntp packet we receive. |
| 129 | // NTP version should be set to same as we used to send, NTP_VERSION |
| 130 | // NTP_VERSION 3 has time in same location so accept that too |
| 131 | // Mode should be set to NTP_MODE_SERVER |
| 132 | |
| 133 | uint8_t versionMode = pbuf_get_at(buf, 0); |
| 134 | uint8_t ver = (versionMode & 0b00111000) >> 3; |
| 135 | uint8_t mode = (versionMode & 0x07); |
| 136 | |
| 137 | if(mode != NTP_MODE_SERVER) { |
| 138 | // Received response from another client - retry |
| 139 | return retry(); |
| 140 | } |
| 141 | |
| 142 | if(ver != NTP_VERSION && ver != (NTP_VERSION - 1)) { |
| 143 | // Received an unsupported version - retry |
| 144 | return retry(); |
| 145 | } |
| 146 | |
| 147 | uint32_t timestamp; |
| 148 | pbuf_copy_partial(buf, ×tamp, sizeof(timestamp), 40); // Copy only timestamp. |
| 149 | timestamp = ntohl(timestamp); |
| 150 | |
| 151 | if(timestamp == 0) { |
| 152 | // Timestamp is not valid |
| 153 | return retry(); |
| 154 | } |
| 155 | |
| 156 | // Unix time starts on Jan 1 1970, subtract 70 years: |
| 157 | uint32_t epoch = timestamp - 0x83AA7E80; |
| 158 | |
| 159 | if(autoUpdateSystemClock) { |
| 160 | SystemClock.setTime(epoch, eTZ_UTC); // update systemclock utc value |
| 161 | } |
| 162 | |
| 163 | if(delegateCompleted) { |
| 164 | delegateCompleted(*this, epoch); |
| 165 | } |
| 166 | |
| 167 | // If auto query is enabled, schedule the next check |
| 168 | setAutoQuery(autoQueryEnabled); |
| 169 | } |