diff options
Diffstat (limited to 'src/ClockTAI.cpp')
| -rw-r--r-- | src/ClockTAI.cpp | 281 |
1 files changed, 123 insertions, 158 deletions
diff --git a/src/ClockTAI.cpp b/src/ClockTAI.cpp index 6d05370..bdef901 100644 --- a/src/ClockTAI.cpp +++ b/src/ClockTAI.cpp @@ -25,9 +25,8 @@ along with ODR-DabMux. If not, see <http://www.gnu.org/licenses/>. */ -/* This file downloads the TAI-UTC bulletins from the USNO servers and/or - * from IETF and parses them so that correct time can be communicated in EDI - * timestamps. +/* This file downloads the TAI-UTC bulletins from the from IETF and parses them + * so that correct time can be communicated in EDI timestamps. * * This file contains self-test code that can be executed by running * g++ -g -Wall -DTEST -DHAVE_CURL -std=c++11 -lcurl -lboost_regex -pthread \ @@ -60,83 +59,67 @@ static bool wait_longer = true; #endif +// Offset between NTP time and POSIX time: +// timestamp_unix = timestamp_ntp - ntp_unix_offset +const int64_t ntp_unix_offset = 2208988800L; + // leap seconds insertion bulletin is available at static const char* tai_ietf_url = "http://www.ietf.org/timezones/data/leap-seconds.list"; // and in the tz distribution static const char* tai_tz_url = "https://raw.githubusercontent.com/eggert/tz/master/leap-seconds.list"; -// leap-seconds.list has a different format from the USNO one - -static const char* tai_usno_url1 = - "http://maia.usno.navy.mil/ser7/tai-utc.dat"; -static const char* tai_usno_url2 = - "http://toshi.nofs.navy.mil/ser7/tai-utc.dat"; -/* Last two lines from USNO bulletin, example: - 2015 JUL 1 =JD 2457204.5 TAI-UTC= 36.0 S + (MJD - 41317.) X 0.0 S - 2017 JAN 1 =JD 2457754.5 TAI-UTC= 37.0 S + (MJD - 41317.) X 0.0 - */ -int ClockTAI::download_offset_task() +static const char* tai_ietf_cache_file = "/tmp/odr-dabmux-leap-seconds.cache"; + +int ClockTAI::get_valid_offset() { int offset = 0; bool offset_valid = false; - // Clear the bulletin - m_bulletin.str(""); - m_bulletin.clear(); - - try { - download_tai_utc_bulletin(tai_ietf_url); + if (bulletin_is_valid()) { +#if TEST + etiLog.level(info) << "Bulletin already valid"; +#endif offset = parse_ietf_bulletin(); offset_valid = true; } - catch (std::runtime_error& e) - { - etiLog.level(warn) << - "TAI-UTC offset from IETF could not be retrieved: " << - e.what(); - } + else { + load_bulletin_from_file(tai_ietf_cache_file); - if (not offset_valid) { - try { - download_tai_utc_bulletin(tai_tz_url); + if (bulletin_is_valid()) { +#if TEST + etiLog.level(info) << "Bulletin from file valid"; +#endif offset = parse_ietf_bulletin(); offset_valid = true; } - catch (std::runtime_error& e) - { - etiLog.level(warn) << - "TAI-UTC offset from TZ distribution could not be retrieved: " << - e.what(); - } - } - - if (not offset_valid) { - try { - download_tai_utc_bulletin(tai_usno_url1); - offset = parse_usno_bulletin(); - offset_valid = true; - } - catch (std::runtime_error& e) - { - etiLog.level(warn) << - "TAI-UTC offset from USNO server #1 could not be retrieved: " << - e.what(); - } - } - - if (not offset_valid) { - try { - download_tai_utc_bulletin(tai_usno_url2); - offset = parse_usno_bulletin(); - offset_valid = true; - } - catch (std::runtime_error& e) - { - etiLog.level(warn) << - "TAI-UTC offset from USNO server #2 could not be retrieved: " << - e.what(); + else { + for (const auto url : {tai_ietf_url, tai_tz_url}) { + try { + download_tai_utc_bulletin(tai_ietf_url); +#if TEST + etiLog.level(info) << "Load bulletin from " << url; +#endif + if (bulletin_is_valid()) { +#if TEST + etiLog.level(info) << "Bulletin from " << url << " valid"; +#endif + offset = parse_ietf_bulletin(); + offset_valid = true; + } + } + catch (std::runtime_error& e) { + etiLog.level(warn) << + "TAI-UTC offset could not be retrieved from " << + url << " : " << e.what(); + } + + if (offset_valid) { + update_cache(tai_ietf_cache_file); + break; + } + } } } @@ -175,7 +158,7 @@ int ClockTAI::get_offset() #else // First time we run we must block until we know // the offset - m_offset = download_offset_task(); + m_offset = get_valid_offset(); m_offset_valid = true; m_bulletin_download_time = std::chrono::system_clock::now(); #endif @@ -217,7 +200,7 @@ int ClockTAI::get_offset() etiLog.level(debug) << " Launch async"; #endif m_offset_future = std::async(std::launch::async, - &ClockTAI::download_offset_task, this); + &ClockTAI::get_valid_offset, this); } } @@ -252,8 +235,6 @@ int ClockTAI::parse_ietf_bulletin() // The difference between NTP timestamps and unix epoch is 70 // years i.e. 2208988800 seconds - const int64_t ntp_unix_offset = 2208988800L; - boost::regex regex_bulletin(R"(([0-9]+)\s+([0-9]+)\s+#.*)"); time_t now = time(nullptr); @@ -262,6 +243,9 @@ int ClockTAI::parse_ietf_bulletin() int tai_utc_offset_valid = false; + m_bulletin.clear(); + m_bulletin.seekg(0); + /* We cannot just take the last line, because it might * be in the future, announcing an upcoming leap second. * @@ -285,10 +269,6 @@ int ClockTAI::parse_ietf_bulletin() std::atol(bulletin_ntp_timestamp.c_str()) - ntp_unix_offset; const int offset = std::atoi(bulletin_offset.c_str()); -#if TEST - std::cerr << "Match for line " << line << std::endl; - std::cerr << " " << timestamp_unix << " < " << now << std::endl; -#endif // Ignore entries announcing leap seconds in the future if (timestamp_unix < now) { tai_utc_offset = offset; @@ -311,114 +291,97 @@ int ClockTAI::parse_ietf_bulletin() return tai_utc_offset; } -int ClockTAI::parse_usno_bulletin() +size_t ClockTAI::fill_bulletin(char *ptr, size_t size, size_t nmemb) { - boost::regex regex_bulletin( - "([0-9]{4}) ([A-Z]{3}) +([0-9]+) =JD +[0-9.]+ +TAI-UTC= *([0-9.]+)"); - /* regex groups: - * Year Month Day Julian date Offset - */ + size_t len = size * nmemb; + for (size_t i = 0; i < len; i++) { + m_bulletin << ptr[i]; + } + return len; +} - const std::array<std::string, 12> months{"JAN", "FEB", "MAR", "APR", "MAY", "JUN", "JUL", "AUG", "SEP", "OCT", "NOV", "DEC"}; +size_t ClockTAI::fill_bulletin_cb( + char *ptr, size_t size, size_t nmemb, void *ctx) +{ + return ((ClockTAI*)ctx)->fill_bulletin(ptr, size, nmemb); +} - /* I'm not certain about the format they would use if the day is a - * two-digit number. Will they keep two spaces after the month? The regex - * should be resilient enough in that case. - */ +void ClockTAI::load_bulletin_from_file(const char* cache_filename) +{ + // Clear the bulletin + m_bulletin.str(""); + m_bulletin.clear(); - time_t now = time(nullptr); - struct tm *utc_time_now = gmtime(&now); + std::ifstream f(cache_filename); + if (not f.good()) { + return; + } - const int year = utc_time_now->tm_year + 1900; - const int month = utc_time_now->tm_mon; // January is 0 - if (month < 0 or month > 11) { - throw std::runtime_error("Invalid value for month"); + m_bulletin << f.rdbuf(); + f.close(); +} + +void ClockTAI::update_cache(const char* cache_filename) +{ + std::ofstream f(cache_filename); + if (not f.good()) { + throw std::runtime_error("TAI-UTC bulletin open cache for writing"); } - const int day = utc_time_now->tm_mday; + m_bulletin.clear(); + m_bulletin.seekg(0); +#if TEST + etiLog.level(info) << "Update cache, state:" << + (m_bulletin.eof() ? " eof" : "") << + (m_bulletin.fail() ? " fail" : "") << + (m_bulletin.bad() ? " bad" : ""); +#endif - int tai_utc_offset = 0; - bool tai_utc_offset_valid = false; + f << m_bulletin.rdbuf(); + f.close(); +} - /* We cannot just take the last line, because it might - * be in the future, announcing an upcoming leap second. - * - * So we need to look at the current date, and compare it - * with the date of the leap second. - */ - for (std::string line; std::getline(m_bulletin, line); ) { +bool ClockTAI::bulletin_is_valid() +{ + // The bulletin contains one line that specifies an expiration date + // in NTP time. If that point in time is in the future, we consider + // the bulletin valid. + // + // The entry looks like this: + //#@ 3707596800 + + boost::regex regex_expiration(R"(#@\s+([0-9]+))"); + time_t now = time(nullptr); + + m_bulletin.clear(); + m_bulletin.seekg(0); + + for (std::string line; std::getline(m_bulletin, line); ) { boost::smatch bulletin_entry; - bool is_match = boost::regex_search(line, bulletin_entry, regex_bulletin); + bool is_match = boost::regex_search(line, bulletin_entry, regex_expiration); if (is_match) { - - if (bulletin_entry.size() != 5) { + if (bulletin_entry.size() != 2) { throw std::runtime_error( - "Incorrect number of matched USNO TAI bulletin entries"); - } - const std::string bulletin_year(bulletin_entry[1]); - const std::string bulletin_month_name(bulletin_entry[2]); - const std::string bulletin_day(bulletin_entry[3]); - const std::string bulletin_offset(bulletin_entry[4]); - - const auto match = std::find(months.begin(), months.end(), bulletin_month_name); - if (match == months.end()) { - std::stringstream s; - s << "Month " << bulletin_month_name << " not in array!"; - std::runtime_error(s.str()); + "Incorrect number of matched TAI IETF bulletin expiration"); } + const std::string expiry_data_str(bulletin_entry[1]); + const int64_t expiry_unix = + std::atol(expiry_data_str.c_str()) - ntp_unix_offset; - if ( (std::atoi(bulletin_year.c_str()) < year) or - - (std::atoi(bulletin_year.c_str()) == year and - std::distance(months.begin(), match) < month) or - - (std::atoi(bulletin_year.c_str()) == year and - std::distance(months.begin(), match) == month and - std::atoi(bulletin_day.c_str()) < day) ) { - tai_utc_offset = std::atoi(bulletin_offset.c_str()); - tai_utc_offset_valid = true; - } -#if TEST - else { - std::cerr << "Ignoring offset " << bulletin_offset << " at date " - << bulletin_year << " " << bulletin_month_name << " " << - bulletin_day << " in the future" << std::endl; - } -#endif - } -#if TEST - else { - std::cerr << "No match for line " << line << std::endl; + return expiry_unix > now; } -#endif - } - - if (not tai_utc_offset_valid) { - throw std::runtime_error("No data in TAI bulletin"); - } - - return tai_utc_offset; -} - -size_t ClockTAI::fill_bulletin(char *ptr, size_t size, size_t nmemb) -{ - size_t len = size * nmemb; - for (size_t i = 0; i < len; i++) { - m_bulletin << ptr[i]; } - return len; -} - -size_t ClockTAI::fill_bulletin_cb( - char *ptr, size_t size, size_t nmemb, void *ctx) -{ - return ((ClockTAI*)ctx)->fill_bulletin(ptr, size, nmemb); + return false; } void ClockTAI::download_tai_utc_bulletin(const char* url) { + // Clear the bulletin + m_bulletin.str(""); + m_bulletin.clear(); + #ifdef HAVE_CURL CURL *curl; CURLcode res; @@ -487,10 +450,12 @@ int main(int argc, char **argv) while (wait_longer) { try { - cerr << "Offset is " << tai.get_offset() << endl; + etiLog.level(info) << + "Offset is " << tai.get_offset(); } catch (std::exception &e) { - cerr << "Exception " << e.what() << endl; + etiLog.level(error) << + "Exception " << e.what(); } std::this_thread::sleep_for(std::chrono::seconds(2)); |