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NTPClient: ignore invalid timestamps #2041

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merged 1 commit into from
Feb 4, 2020
Merged

NTPClient: ignore invalid timestamps #2041

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45 changes: 27 additions & 18 deletions Sming/Core/Network/NtpClient.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -122,6 +122,7 @@ void NtpClient::onReceive(pbuf* buf, IpAddress remoteIP, uint16_t remotePort)
debug_d("NtpClient::onReceive(%s:%u)", remoteIP.toString().c_str(), remotePort);

stopTimer();
auto retry = [this]() { startTimer(NTP_RESPONSE_TIMEOUT_MS); };

// We do some basic check to see if it really is a ntp packet we receive.
// NTP version should be set to same as we used to send, NTP_VERSION
Expand All @@ -132,28 +133,36 @@ void NtpClient::onReceive(pbuf* buf, IpAddress remoteIP, uint16_t remotePort)
uint8_t ver = (versionMode & 0b00111000) >> 3;
uint8_t mode = (versionMode & 0x07);

if(mode == NTP_MODE_SERVER && (ver == NTP_VERSION || ver == (NTP_VERSION - 1))) {
//Most likely a correct NTP packet received.
if(mode != NTP_MODE_SERVER) {
// Received response from another client - retry
return retry();
}

uint32_t timestamp;
pbuf_copy_partial(buf, &timestamp, sizeof(timestamp), 40); // Copy only timestamp.
timestamp = ntohl(timestamp);
if(ver != NTP_VERSION && ver != (NTP_VERSION - 1)) {
// Received an unsupported version - retry
return retry();
}

// Unix time starts on Jan 1 1970, subtract 70 years:
uint32_t epoch = timestamp - 0x83AA7E80;
uint32_t timestamp;
pbuf_copy_partial(buf, &timestamp, sizeof(timestamp), 40); // Copy only timestamp.
timestamp = ntohl(timestamp);

if(autoUpdateSystemClock) {
SystemClock.setTime(epoch, eTZ_UTC); // update systemclock utc value
}
if(timestamp == 0) {
// Timestamp is not valid
return retry();
}

if(delegateCompleted) {
delegateCompleted(*this, epoch);
}
// Unix time starts on Jan 1 1970, subtract 70 years:
uint32_t epoch = timestamp - 0x83AA7E80;

// If auto query is enabled, schedule the next check
setAutoQuery(autoQueryEnabled);
} else {
// Got a dodgy packet so treat it as we would a response failure
startTimer(NTP_RESPONSE_TIMEOUT_MS);
if(autoUpdateSystemClock) {
SystemClock.setTime(epoch, eTZ_UTC); // update systemclock utc value
}

if(delegateCompleted) {
delegateCompleted(*this, epoch);
}

// If auto query is enabled, schedule the next check
setAutoQuery(autoQueryEnabled);
}