mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-09-11 13:36:13 +03:00
Each of these strings would previously rely on StringView's char const* constructor overload, which would call __builtin_strlen on the string. Since we now have operator ""sv, we can replace these with much simpler versions. This opens the door to being able to remove StringView(char const*). No functional changes.
328 lines
12 KiB
C++
328 lines
12 KiB
C++
/*
|
|
* Copyright (c) 2020, Nico Weber <thakis@chromium.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#define _BSD_SOURCE
|
|
#define _DEFAULT_SOURCE
|
|
#include <AK/Assertions.h>
|
|
#include <AK/Endian.h>
|
|
#include <AK/Random.h>
|
|
#include <LibCore/ArgsParser.h>
|
|
#include <LibCore/System.h>
|
|
#include <LibMain/Main.h>
|
|
#include <arpa/inet.h>
|
|
#include <inttypes.h>
|
|
#include <math.h>
|
|
#include <netdb.h>
|
|
#include <netinet/in.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/time.h>
|
|
#include <sys/uio.h>
|
|
#include <time.h>
|
|
|
|
// An NtpTimestamp is a 64-bit integer that's a 32.32 binary-fixed point number.
|
|
// The integral part in the upper 32 bits represents seconds since 1900-01-01.
|
|
// The fractional part in the lower 32 bits stores fractional bits times 2 ** 32.
|
|
using NtpTimestamp = uint64_t;
|
|
|
|
struct [[gnu::packed]] NtpPacket {
|
|
uint8_t li_vn_mode;
|
|
uint8_t stratum;
|
|
int8_t poll;
|
|
int8_t precision;
|
|
|
|
uint32_t root_delay;
|
|
uint32_t root_dispersion;
|
|
uint32_t reference_id;
|
|
|
|
NtpTimestamp reference_timestamp;
|
|
NtpTimestamp origin_timestamp;
|
|
NtpTimestamp receive_timestamp;
|
|
NtpTimestamp transmit_timestamp;
|
|
|
|
uint8_t leap_information() const { return li_vn_mode >> 6; }
|
|
uint8_t version_number() const { return (li_vn_mode >> 3) & 7; }
|
|
uint8_t mode() const { return li_vn_mode & 7; }
|
|
};
|
|
static_assert(AssertSize<NtpPacket, 48>());
|
|
|
|
// NTP measures time in seconds since 1900-01-01, POSIX in seconds since 1970-01-01.
|
|
// 1900 wasn't a leap year, so there are 70/4 leap years between 1900 and 1970.
|
|
// Overflows a 32-bit signed int, but not a 32-bit unsigned int.
|
|
unsigned const SecondsFrom1900To1970 = (70u * 365u + 70u / 4u) * 24u * 60u * 60u;
|
|
|
|
static NtpTimestamp ntp_timestamp_from_timeval(timeval const& t)
|
|
{
|
|
VERIFY(t.tv_usec >= 0 && t.tv_usec < 1'000'000); // Fits in 20 bits when normalized.
|
|
|
|
// Seconds just need translation to the different origin.
|
|
uint32_t seconds = t.tv_sec + SecondsFrom1900To1970;
|
|
|
|
// Fractional bits are decimal fixed point (*1'000'000) in timeval, but binary fixed-point (* 2**32) in NTP timestamps.
|
|
uint32_t fractional_bits = static_cast<uint32_t>((static_cast<uint64_t>(t.tv_usec) << 32) / 1'000'000);
|
|
|
|
return (static_cast<NtpTimestamp>(seconds) << 32) | fractional_bits;
|
|
}
|
|
|
|
static timeval timeval_from_ntp_timestamp(NtpTimestamp const& ntp_timestamp)
|
|
{
|
|
timeval t;
|
|
t.tv_sec = static_cast<time_t>(ntp_timestamp >> 32) - SecondsFrom1900To1970;
|
|
t.tv_usec = static_cast<suseconds_t>((static_cast<uint64_t>(ntp_timestamp & 0xFFFFFFFFu) * 1'000'000) >> 32);
|
|
return t;
|
|
}
|
|
|
|
static String format_ntp_timestamp(NtpTimestamp ntp_timestamp)
|
|
{
|
|
char buffer[28]; // YYYY-MM-DDTHH:MM:SS.UUUUUUZ is 27 characters long.
|
|
timeval t = timeval_from_ntp_timestamp(ntp_timestamp);
|
|
struct tm tm;
|
|
gmtime_r(&t.tv_sec, &tm);
|
|
size_t written = strftime(buffer, sizeof(buffer), "%Y-%m-%dT%T.", &tm);
|
|
VERIFY(written == 20);
|
|
written += snprintf(buffer + written, sizeof(buffer) - written, "%06d", (int)t.tv_usec);
|
|
VERIFY(written == 26);
|
|
buffer[written++] = 'Z';
|
|
buffer[written] = '\0';
|
|
return buffer;
|
|
}
|
|
#ifdef __serenity__
|
|
ErrorOr<int> serenity_main(Main::Arguments arguments)
|
|
#else
|
|
int main(int argc, char** argv)
|
|
#endif
|
|
{
|
|
#ifdef __serenity__
|
|
TRY(Core::System::pledge("stdio inet unix settime"));
|
|
#endif
|
|
|
|
bool adjust_time = false;
|
|
bool set_time = false;
|
|
bool verbose = false;
|
|
// FIXME: Change to serenityos.pool.ntp.org once https://manage.ntppool.org/manage/vendor/zone?a=km5a8h&id=vz-14154g is approved.
|
|
// Other NTP servers:
|
|
// - time.nist.gov
|
|
// - time.apple.com
|
|
// - time.cloudflare.com (has NTS), https://blog.cloudflare.com/secure-time/
|
|
// - time.windows.com
|
|
//
|
|
// Leap seconds smearing NTP servers:
|
|
// - time.facebook.com , https://engineering.fb.com/production-engineering/ntp-service/ , sine-smears over 18 hours
|
|
// - time.google.com , https://developers.google.com/time/smear , linear-smears over 24 hours
|
|
char const* host = "time.google.com";
|
|
Core::ArgsParser args_parser;
|
|
args_parser.add_option(adjust_time, "Gradually adjust system time (requires root)", "adjust", 'a');
|
|
args_parser.add_option(set_time, "Immediately set system time (requires root)", "set", 's');
|
|
args_parser.add_option(verbose, "Verbose output", "verbose", 'v');
|
|
args_parser.add_positional_argument(host, "NTP server", "host", Core::ArgsParser::Required::No);
|
|
#ifdef __serenity__
|
|
args_parser.parse(arguments);
|
|
#else
|
|
args_parser.parse(argc, argv);
|
|
#endif
|
|
|
|
if (adjust_time && set_time) {
|
|
warnln("-a and -s are mutually exclusive");
|
|
return 1;
|
|
}
|
|
|
|
#ifdef __serenity__
|
|
if (!adjust_time && !set_time) {
|
|
TRY(Core::System::pledge("stdio inet unix"));
|
|
}
|
|
#endif
|
|
|
|
auto* hostent = gethostbyname(host);
|
|
if (!hostent) {
|
|
warnln("Lookup failed for '{}'", host);
|
|
return 1;
|
|
}
|
|
|
|
#ifdef __serenity__
|
|
TRY(Core::System::pledge((adjust_time || set_time) ? "stdio inet settime"sv : "stdio inet"sv));
|
|
TRY(Core::System::unveil(nullptr, nullptr));
|
|
#endif
|
|
|
|
int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
|
|
if (fd < 0) {
|
|
perror("socket");
|
|
return 1;
|
|
}
|
|
|
|
struct timeval timeout {
|
|
5, 0
|
|
};
|
|
if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)) < 0) {
|
|
perror("setsockopt");
|
|
return 1;
|
|
}
|
|
|
|
int enable = 1;
|
|
if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMP, &enable, sizeof(enable)) < 0) {
|
|
perror("setsockopt");
|
|
return 1;
|
|
}
|
|
|
|
sockaddr_in peer_address;
|
|
memset(&peer_address, 0, sizeof(peer_address));
|
|
peer_address.sin_family = AF_INET;
|
|
peer_address.sin_port = htons(123);
|
|
peer_address.sin_addr.s_addr = *(in_addr_t const*)hostent->h_addr_list[0];
|
|
|
|
NtpPacket packet;
|
|
memset(&packet, 0, sizeof(packet));
|
|
packet.li_vn_mode = (4 << 3) | 3; // Version 4, client connection.
|
|
|
|
// The server will copy the transmit_timestamp to origin_timestamp in the reply.
|
|
// To not leak the local time, keep the time we sent the packet locally and
|
|
// send random bytes to the server.
|
|
auto random_transmit_timestamp = get_random<NtpTimestamp>();
|
|
timeval local_transmit_time;
|
|
gettimeofday(&local_transmit_time, nullptr);
|
|
packet.transmit_timestamp = random_transmit_timestamp;
|
|
|
|
ssize_t rc;
|
|
rc = sendto(fd, &packet, sizeof(packet), 0, (const struct sockaddr*)&peer_address, sizeof(peer_address));
|
|
if (rc < 0) {
|
|
perror("sendto");
|
|
return 1;
|
|
}
|
|
if ((size_t)rc < sizeof(packet)) {
|
|
warnln("incomplete packet send");
|
|
return 1;
|
|
}
|
|
|
|
iovec iov { &packet, sizeof(packet) };
|
|
char control_message_buffer[CMSG_SPACE(sizeof(timeval))];
|
|
msghdr msg = { &peer_address, sizeof(peer_address), &iov, 1, control_message_buffer, sizeof(control_message_buffer), 0 };
|
|
rc = recvmsg(fd, &msg, 0);
|
|
if (rc < 0) {
|
|
perror("recvmsg");
|
|
return 1;
|
|
}
|
|
timeval userspace_receive_time;
|
|
gettimeofday(&userspace_receive_time, nullptr);
|
|
if ((size_t)rc < sizeof(packet)) {
|
|
warnln("incomplete packet recv");
|
|
return 1;
|
|
}
|
|
|
|
cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
|
|
VERIFY(cmsg->cmsg_level == SOL_SOCKET);
|
|
VERIFY(cmsg->cmsg_type == SCM_TIMESTAMP);
|
|
VERIFY(!CMSG_NXTHDR(&msg, cmsg));
|
|
timeval kernel_receive_time;
|
|
memcpy(&kernel_receive_time, CMSG_DATA(cmsg), sizeof(kernel_receive_time));
|
|
|
|
// Checks 3 and 4 from end of section 5 of rfc4330.
|
|
if (packet.version_number() != 3 && packet.version_number() != 4) {
|
|
warnln("unexpected version number {}", packet.version_number());
|
|
return 1;
|
|
}
|
|
if (packet.mode() != 4) { // 4 means "server", which should be the reply to our 3 ("client") request.
|
|
warnln("unexpected mode {}", packet.mode());
|
|
return 1;
|
|
}
|
|
if (packet.stratum == 0 || packet.stratum >= 16) {
|
|
warnln("unexpected stratum value {}", packet.stratum);
|
|
return 1;
|
|
}
|
|
if (packet.origin_timestamp != random_transmit_timestamp) {
|
|
warnln("expected {:#016x} as origin timestamp, got {:#016x}", random_transmit_timestamp, packet.origin_timestamp);
|
|
return 1;
|
|
}
|
|
if (packet.transmit_timestamp == 0) {
|
|
warnln("got transmit_timestamp 0");
|
|
return 1;
|
|
}
|
|
|
|
NtpTimestamp origin_timestamp = ntp_timestamp_from_timeval(local_transmit_time);
|
|
NtpTimestamp receive_timestamp = be64toh(packet.receive_timestamp);
|
|
NtpTimestamp transmit_timestamp = be64toh(packet.transmit_timestamp);
|
|
NtpTimestamp destination_timestamp = ntp_timestamp_from_timeval(kernel_receive_time);
|
|
|
|
timeval kernel_to_userspace_latency;
|
|
timersub(&userspace_receive_time, &kernel_receive_time, &kernel_to_userspace_latency);
|
|
|
|
if (set_time) {
|
|
// FIXME: Do all the time filtering described in 5905, or at least correct for time of flight.
|
|
timeval t = timeval_from_ntp_timestamp(transmit_timestamp);
|
|
if (settimeofday(&t, nullptr) < 0) {
|
|
perror("settimeofday");
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
if (verbose) {
|
|
outln("NTP response from {}:", inet_ntoa(peer_address.sin_addr));
|
|
outln("Leap Information: {}", packet.leap_information());
|
|
outln("Version Number: {}", packet.version_number());
|
|
outln("Mode: {}", packet.mode());
|
|
outln("Stratum: {}", packet.stratum);
|
|
outln("Poll: {}", packet.stratum);
|
|
outln("Precision: {}", packet.precision);
|
|
outln("Root delay: {:x}", ntohl(packet.root_delay));
|
|
outln("Root dispersion: {:x}", ntohl(packet.root_dispersion));
|
|
|
|
u32 ref_id = ntohl(packet.reference_id);
|
|
out("Reference ID: {:x}", ref_id);
|
|
if (packet.stratum == 1) {
|
|
out(" ('{:c}{:c}{:c}{:c}')", (ref_id & 0xff000000) >> 24, (ref_id & 0xff0000) >> 16, (ref_id & 0xff00) >> 8, ref_id & 0xff);
|
|
}
|
|
outln();
|
|
|
|
outln("Reference timestamp: {:#016x} ({})", be64toh(packet.reference_timestamp), format_ntp_timestamp(be64toh(packet.reference_timestamp)).characters());
|
|
outln("Origin timestamp: {:#016x} ({})", origin_timestamp, format_ntp_timestamp(origin_timestamp).characters());
|
|
outln("Receive timestamp: {:#016x} ({})", receive_timestamp, format_ntp_timestamp(receive_timestamp).characters());
|
|
outln("Transmit timestamp: {:#016x} ({})", transmit_timestamp, format_ntp_timestamp(transmit_timestamp).characters());
|
|
outln("Destination timestamp: {:#016x} ({})", destination_timestamp, format_ntp_timestamp(destination_timestamp).characters());
|
|
|
|
// When the system isn't under load, user-space t and packet_t are identical. If a shell with `yes` is running, it can be as high as 30ms in this program,
|
|
// which gets user-space time immediately after the recvmsg() call. In programs that have an event loop reading from multiple sockets, it could be higher.
|
|
outln("Receive latency: {}.{:06} s", (i64)kernel_to_userspace_latency.tv_sec, (int)kernel_to_userspace_latency.tv_usec);
|
|
}
|
|
|
|
// Parts of the "Clock Filter" computations, https://tools.ietf.org/html/rfc5905#section-10
|
|
NtpTimestamp T1 = origin_timestamp;
|
|
NtpTimestamp T2 = receive_timestamp;
|
|
NtpTimestamp T3 = transmit_timestamp;
|
|
NtpTimestamp T4 = destination_timestamp;
|
|
auto timestamp_difference_in_seconds = [](NtpTimestamp from, NtpTimestamp to) {
|
|
return static_cast<i64>(to - from) >> 32;
|
|
};
|
|
|
|
// The network round-trip time of the request.
|
|
// T4-T1 is the wall clock roundtrip time, in local ticks.
|
|
// T3-T2 is the server side processing time, in server ticks.
|
|
double delay_s = timestamp_difference_in_seconds(T1, T4) - timestamp_difference_in_seconds(T2, T3);
|
|
|
|
// The offset from local time to server time, ignoring network delay.
|
|
// Both T2-T1 and T3-T4 estimate this; this takes the average of both.
|
|
// Or, equivalently, (T1+T4)/2 estimates local time, (T2+T3)/2 estimate server time, this is the difference.
|
|
double offset_s = 0.5 * (timestamp_difference_in_seconds(T1, T2) + timestamp_difference_in_seconds(T4, T3));
|
|
if (verbose)
|
|
outln("Delay: {}", delay_s);
|
|
outln("Offset: {}", offset_s);
|
|
|
|
if (adjust_time) {
|
|
long delta_us = static_cast<long>(round(offset_s * 1'000'000));
|
|
timeval delta_timeval;
|
|
delta_timeval.tv_sec = delta_us / 1'000'000;
|
|
delta_timeval.tv_usec = delta_us % 1'000'000;
|
|
if (delta_timeval.tv_usec < 0) {
|
|
delta_timeval.tv_sec--;
|
|
delta_timeval.tv_usec += 1'000'000;
|
|
}
|
|
if (adjtime(&delta_timeval, nullptr) < 0) {
|
|
perror("adjtime set");
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|