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//! Types and constants that precisely match the specification. //! //! Provides `ReadBytes` and `WriteBytes` implementations which extend the byteorder crate //! `WriteBytesExt` and `ReadBytesExt` traits with the ability to read and write types from the NTP //! protocol respectively. //! //! Documentation is largely derived (and often copied directly) from IETF RFC 5905. use byteorder::{ReadBytesExt, WriteBytesExt, BE}; use conv::TryFrom; use std::{fmt, io}; /// NTP port number. pub const PORT: u8 = 123; /// Frequency tolerance PHI (s/s). pub const TOLERANCE: f64 = 15e-6; /// Minimum poll exponent (16 s). pub const MINPOLL: u8 = 4; /// Maximum poll exponent (36 h). pub const MAXPOLL: u8 = 17; /// Maximum dispersion (16 s). pub const MAXDISP: f64 = 16.0; /// Minimum dispersion increment (s). pub const MINDISP: f64 = 0.005; /// Distance threshold (1 s). pub const MAXDIST: u8 = 1; /// Maximum stratum number. pub const MAXSTRAT: u8 = 16; /// A trait for writing any of the Network Time Protocol types to network-endian bytes. /// /// A blanket implementation is provided for all types that implement `byteorder::WriteBytesExt`. pub trait WriteBytes { fn write_bytes<P: WriteToBytes>(&mut self, protocol: P) -> io::Result<()>; } /// A trait for reading any of the Network Time Protocol types from network-endian bytes. /// /// A blanket implementation is provided for all types that implement `byteorder::ReadBytesExt`. pub trait ReadBytes { fn read_bytes<P: ReadFromBytes>(&mut self) -> io::Result<P>; } /// Network Time Protocol types that may be written to network endian bytes. pub trait WriteToBytes { /// Write the command to bytes. fn write_to_bytes<W: WriteBytesExt>(&self, writer: W) -> io::Result<()>; } /// Network Time Protocol types that may be read from network endian bytes. pub trait ReadFromBytes: Sized { /// Read the command from bytes. fn read_from_bytes<R: ReadBytesExt>(reader: R) -> io::Result<Self>; } /// Types that have a constant size when written to or read from bytes. pub trait ConstPackedSizeBytes { const PACKED_SIZE_BYTES: usize; } /// **NTP Short Format** - Used in delay and dispersion header fields where the full resolution and /// range of the other formats are not justified. It includes a 16-bit unsigned seconds field and a /// 16-bit fraction field. /// /// ### Layout /// /// ```ignore /// 0 1 2 3 /// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Seconds | Fraction | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// ``` #[repr(C)] #[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)] pub struct ShortFormat { pub seconds: u16, pub fraction: u16, } /// **NTP Timestamp Format** - Used in packet headers and other places with limited word size. It /// includes a 32-bit unsigned seconds field spanning 136 years and a 32-bit fraction field /// resolving 232 picoseconds. /// /// The prime epoch is 0 h 1 January 1900 UTC, when all bits are zero. /// /// ### Layout /// /// ```ignore /// 0 1 2 3 /// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Seconds | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Fraction | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// ``` #[repr(C)] #[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)] pub struct TimestampFormat { pub seconds: u32, pub fraction: u32, } /// **NTP Date Format** - The prime epoch, or base date of era 0, is 0 h 1 January 1900 UTC, when all /// bits are zero. Dates are relative to the prime epoch; values greater than zero represent times /// after that date; values less than zero represent times before it. /// /// Note that the `era_offset` field has the same interpretation as the `seconds` field of the /// `TimestampFormat` type. /// /// ```ignore /// 0 1 2 3 /// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Era Number | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Era Offset | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// | Fraction | /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// ``` #[repr(C)] #[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)] pub struct DateFormat { pub era_number: i32, pub era_offset: u32, pub fraction: u64, } custom_derive! { /// A 2-bit integer warning of an impending leap second to be inserted or deleted in the last /// minute of the current month with values defined below: /// /// Note that this field is packed in the actual header. /// /// As the only constructors are via associated constants, it should be impossible to create an /// invalid `LeapIndicator`. #[repr(u8)] #[derive(Copy, Clone, Debug, Eq, Hash, PartialEq, TryFrom(u8))] pub enum LeapIndicator { /// No leap required. NoWarning = 0, /// Last minute of the day has 61 seconds. AddOne = 1, /// Last minute of the day has 59 seconds. SubOne = 2, /// Clock unsynchronized. Unknown = 3, } } /// A 3-bit integer representing the NTP version number, currently 4. /// /// Note that while this struct is 8-bits, this field is packed to 3 in the actual header. /// /// As the only constructors are via associated constants, it should be impossible to create an /// invalid `Version`. #[derive(Copy, Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)] pub struct Version(u8); custom_derive! { /// A 3-bit integer representing the mode. /// /// Note that while this struct is 8-bits, this field is packed to 3 in the actual header. /// /// As the only constructors are via associated constants, it should be impossible to create an /// invalid `Mode`. #[repr(u8)] #[derive(Copy, Clone, Debug, Eq, Hash, PartialEq, TryFrom(u8))] pub enum Mode { Reserved = 0, SymmetricActive = 1, SymmetricPassive = 2, Client = 3, Server = 4, Broadcast = 5, NtpControlMessage = 6, ReservedForPrivateUse = 7, } } /// An 8-bit integer representing the stratum. /// /// ```ignore /// +--------+-----------------------------------------------------+ /// | Value | Meaning | /// +--------+-----------------------------------------------------+ /// | 0 | unspecified or invalid | /// | 1 | primary server (e.g., equipped with a GPS receiver) | /// | 2-15 | secondary server (via NTP) | /// | 16 | unsynchronized | /// | 17-255 | reserved | /// +--------+-----------------------------------------------------+ /// ``` /// /// It is customary to map the stratum value 0 in received packets to `MAXSTRAT` in the peer /// variable p.stratum and to map p.stratum values of `MAXSTRAT` or greater to 0 in transmitted /// packets. This allows reference clocks, which normally appear at stratum 0, to be conveniently /// mitigated using the same clock selection algorithms used for external sources. #[derive(Copy, Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)] pub struct Stratum(pub u8); /// A 32-bit code identifying the particular server or reference clock. /// /// The interpretation depends on the value in the stratum field: /// /// - For packet stratum 0 (unspecified or invalid), this is a four-character ASCII [RFC1345] /// string, called the "kiss code", used for debugging and monitoring purposes. /// - For stratum 1 (reference clock), this is a four-octet, left-justified, zero-padded ASCII /// string assigned to the reference clock. /// /// The authoritative list of Reference Identifiers is maintained by IANA; however, any string /// beginning with the ASCII character "X" is reserved for unregistered experimentation and /// development. #[repr(u32)] #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] pub enum ReferenceIdentifier { PrimarySource(PrimarySource), /// The reference identifier of the secondary or client server. Can be used to detect timing /// loops. /// /// If using the IPv4 address family, the identifier is the four-octet IPv4 address. /// /// If using the IPv6 address family, it is the first four octets of the MD5 hash of the IPv6 /// address. Note that when using the IPv6 address family on a NTPv4 server with a NTPv3 /// client, the Reference Identifier field appears to be a random value and a timing loop might /// not be detected. SecondaryOrClient([u8; 4]), KissOfDeath(KissOfDeath), } // Convert an ascii string to a big-endian u32. macro_rules! code_to_u32 { ($w:expr) => { (($w[3] as u32) << 0) | (($w[2] as u32) << 8) | (($w[1] as u32) << 16) | (($w[0] as u32) << 24) | ((*$w as [u8; 4])[0] as u32 * 0) }; } custom_derive! { /// A four-octet, left-justified, zero-padded ASCII string assigned to the reference clock. /// /// The authoritative list of Reference Identifiers is maintained by IANA; however, any string /// beginning with the ASCII character "X" is reserved for unregistered experimentation and /// development. #[repr(u32)] #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, TryFrom(u32))] pub enum PrimarySource { Goes = code_to_u32!(b"GOES"), Gps = code_to_u32!(b"GPS\0"), Cdma = code_to_u32!(b"CDMA"), Gal = code_to_u32!(b"GAL\0"), Pps = code_to_u32!(b"PPS\0"), Irig = code_to_u32!(b"IRIG"), Wwvb = code_to_u32!(b"WWVB"), Dcf = code_to_u32!(b"DCF\0"), Hgb = code_to_u32!(b"HGB\0"), Msf = code_to_u32!(b"MSF\0"), Jjy = code_to_u32!(b"JJY\0"), Lorc = code_to_u32!(b"LORC"), Tdf = code_to_u32!(b"TDF\0"), Chu = code_to_u32!(b"CHU\0"), Wwv = code_to_u32!(b"WWV\0"), Wwvh = code_to_u32!(b"WWVH"), Nist = code_to_u32!(b"NIST"), Acts = code_to_u32!(b"ACTS"), Usno = code_to_u32!(b"USNO"), Ptb = code_to_u32!(b"PTB\0"), Goog = code_to_u32!(b"GOOG"), Locl = code_to_u32!(b"LOCL"), Cesm = code_to_u32!(b"CESM"), Rbdm = code_to_u32!(b"RBDM"), Omeg = code_to_u32!(b"OMEG"), Dcn = code_to_u32!(b"DCN\0"), Tsp = code_to_u32!(b"TSP\0"), Dts = code_to_u32!(b"DTS\0"), Atom = code_to_u32!(b"ATOM"), Vlf = code_to_u32!(b"VLF\0"), Opps = code_to_u32!(b"OPPS"), Free = code_to_u32!(b"FREE"), Init = code_to_u32!(b"INIT"), Null = 0, } } custom_derive! { /// If the Stratum field is 0, which implies unspecified or invalid, the Reference Identifier /// field can be used to convey messages useful for status reporting and access control. These /// are called **Kiss-o'-Death** (KoD) packets and the ASCII messages they convey are called /// kiss codes. /// /// The KoD packets got their name because an early use was to tell clients to stop sending /// packets that violate server access controls. The kiss codes can provide useful information /// for an intelligent client, either NTPv4 or SNTPv4. Kiss codes are encoded in four-character /// ASCII strings that are left justified and zero filled. The strings are designed for /// character displays and log files. /// /// Recipients of kiss codes MUST inspect them and, in the following cases, take the actions /// described. #[repr(u32)] #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, TryFrom(u32))] pub enum KissOfDeath { /// The client MUST demobilize any associations to that server and stop sending packets to it. Deny = code_to_u32!(b"DENY"), /// The client MUST demobilize any associations to that server and stop sending packets to it. Rstr = code_to_u32!(b"RSTR"), /// The client MUST immediately reduce its polling interval to that server and continue to /// reduce it each time it receives a RATE kiss code. Rate = code_to_u32!(b"RATE"), } } /// **Packet Header** - The most important state variables from an external point of view are the /// packet header variables described here. /// /// The NTP packet header consists of an integral number of 32-bit (4 octet) words in network byte /// order. The packet format consists of three components: the header itself, one or more optional /// extension fields, and an optional message authentication code (MAC). /// /// ```ignore /// +-----------+------------+-----------------------+ /// | Name | Formula | Description | /// +-----------+------------+-----------------------+ /// | leap | leap | leap indicator (LI) | /// | version | version | version number (VN) | /// | mode | mode | mode | /// | stratum | stratum | stratum | /// | poll | poll | poll exponent | /// | precision | rho | precision exponent | /// | rootdelay | delta_r | root delay | /// | rootdisp | epsilon_r | root dispersion | /// | refid | refid | reference ID | /// | reftime | reftime | reference timestamp | /// | org | T1 | origin timestamp | /// | rec | T2 | receive timestamp | /// | xmt | T3 | transmit timestamp | /// | dst | T4 | destination timestamp | /// | keyid | keyid | key ID | /// | dgst | dgst | message digest | /// +-----------+------------+-----------------------+ /// ``` /// /// ### Format /// /// The NTP packet is a UDP datagram [RFC0768]. Some fields use multiple words and others are /// packed in smaller fields within a word. The NTP packet header shown below has 12 words followed /// by optional extension fields and finally an optional message authentication code (MAC) /// consisting of the Key Identifier field and Message Digest field. /// /// ```ignore /// 0 1 2 3 /// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// |LI | VN |Mode | Stratum | Poll | Precision | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Root Delay | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Root Dispersion | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Reference ID | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// + Reference Timestamp (64) + /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// + Origin Timestamp (64) + /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// + Receive Timestamp (64) + /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// + Transmit Timestamp (64) + /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// . . /// . Extension Field 1 (variable) . /// . . /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// . . /// . Extension Field 2 (variable) . /// . . /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Key Identifier | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// | dgst (128) | /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// ``` #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] pub struct Packet { pub leap_indicator: LeapIndicator, pub version: Version, pub mode: Mode, pub stratum: Stratum, /// 8-bit signed integer representing the maximum interval between successive messages, in log2 /// seconds. Suggested default limits for minimum and maximum poll intervals are 6 and 10, /// respectively. pub poll: i8, /// 8-bit signed integer representing the precision of the system clock, in log2 seconds. For /// instance, a value of -18 corresponds to a precision of about one microsecond. The precision /// can be determined when the service first starts up as the minimum time of several /// iterations to read the system clock. pub precision: i8, /// Total round-trip delay to the reference clock, in NTP short format. pub root_delay: ShortFormat, /// Total dispersion to the reference clock, in NTP short format. pub root_dispersion: ShortFormat, pub reference_id: ReferenceIdentifier, /// Time when the system clock was last set or corrected. pub reference_timestamp: TimestampFormat, /// Time at the client when the request departed for the server. pub origin_timestamp: TimestampFormat, /// Time at the server when the request arrived from the client. pub receive_timestamp: TimestampFormat, /// Time at the server when the response left for the client. pub transmit_timestamp: TimestampFormat, } /// The consecutive types within the first packed byte in the NTP packet. pub type PacketByte1 = (LeapIndicator, Version, Mode); // Inherent implementations. impl PrimarySource { /// The bytestring representation of the primary source. pub fn bytes(&self) -> [u8; 4] { be_u32_to_bytes(*self as u32) } } impl Version { pub const V1: Self = Version(1); pub const V2: Self = Version(2); pub const V3: Self = Version(3); pub const V4: Self = Version(4); /// Whether or not the version is a known, valid version. pub fn is_known(&self) -> bool { self.0 >= 1 && self.0 <= 4 } } impl Stratum { /// Unspecified or invalid. pub const UNSPECIFIED: Self = Stratum(0); /// The primary server (e.g. equipped with a GPS receiver. pub const PRIMARY: Self = Stratum(1); /// The minimum value specifying a secondary server (via NTP). pub const SECONDARY_MIN: Self = Stratum(2); /// The maximum value specifying a secondary server (via NTP). pub const SECONDARY_MAX: Self = Stratum(15); /// An unsynchronized stratum. pub const UNSYNCHRONIZED: Self = Stratum(16); /// The maximum valid stratum value. pub const MAX: Self = Stratum(16); /// Whether or not the stratum represents a secondary server. pub fn is_secondary(&self) -> bool { Self::SECONDARY_MIN <= *self && *self <= Self::SECONDARY_MAX } /// Whether or not the stratum is in the reserved range. pub fn is_reserved(&self) -> bool { *self > Self::MAX } } // Size implementations. impl ConstPackedSizeBytes for ShortFormat { const PACKED_SIZE_BYTES: usize = 4; } impl ConstPackedSizeBytes for TimestampFormat { const PACKED_SIZE_BYTES: usize = 8; } impl ConstPackedSizeBytes for DateFormat { const PACKED_SIZE_BYTES: usize = 16; } impl ConstPackedSizeBytes for Stratum { const PACKED_SIZE_BYTES: usize = 1; } impl ConstPackedSizeBytes for ReferenceIdentifier { const PACKED_SIZE_BYTES: usize = 4; } impl ConstPackedSizeBytes for PacketByte1 { const PACKED_SIZE_BYTES: usize = 1; } impl ConstPackedSizeBytes for Packet { const PACKED_SIZE_BYTES: usize = PacketByte1::PACKED_SIZE_BYTES + Stratum::PACKED_SIZE_BYTES + 2 + ShortFormat::PACKED_SIZE_BYTES * 2 + ReferenceIdentifier::PACKED_SIZE_BYTES + TimestampFormat::PACKED_SIZE_BYTES * 4; } // Writer implementations. impl<W> WriteBytes for W where W: WriteBytesExt, { fn write_bytes<P: WriteToBytes>(&mut self, protocol: P) -> io::Result<()> { protocol.write_to_bytes(self) } } impl<'a, P> WriteToBytes for &'a P where P: WriteToBytes, { fn write_to_bytes<W: WriteBytesExt>(&self, writer: W) -> io::Result<()> { (*self).write_to_bytes(writer) } } impl WriteToBytes for ShortFormat { fn write_to_bytes<W: WriteBytesExt>(&self, mut writer: W) -> io::Result<()> { writer.write_u16::<BE>(self.seconds)?; writer.write_u16::<BE>(self.fraction)?; Ok(()) } } impl WriteToBytes for TimestampFormat { fn write_to_bytes<W: WriteBytesExt>(&self, mut writer: W) -> io::Result<()> { writer.write_u32::<BE>(self.seconds)?; writer.write_u32::<BE>(self.fraction)?; Ok(()) } } impl WriteToBytes for DateFormat { fn write_to_bytes<W: WriteBytesExt>(&self, mut writer: W) -> io::Result<()> { writer.write_i32::<BE>(self.era_number)?; writer.write_u32::<BE>(self.era_offset)?; writer.write_u64::<BE>(self.fraction)?; Ok(()) } } impl WriteToBytes for Stratum { fn write_to_bytes<W: WriteBytesExt>(&self, mut writer: W) -> io::Result<()> { writer.write_u8(self.0)?; Ok(()) } } impl WriteToBytes for ReferenceIdentifier { fn write_to_bytes<W: WriteBytesExt>(&self, mut writer: W) -> io::Result<()> { match *self { ReferenceIdentifier::KissOfDeath(kod) => { writer.write_u32::<BE>(kod as u32)?; } ReferenceIdentifier::PrimarySource(src) => { writer.write_u32::<BE>(src as u32)?; } ReferenceIdentifier::SecondaryOrClient(arr) => { writer.write_u32::<BE>(code_to_u32!(&arr))?; } } Ok(()) } } impl WriteToBytes for (LeapIndicator, Version, Mode) { fn write_to_bytes<W: WriteBytesExt>(&self, mut writer: W) -> io::Result<()> { let (li, vn, mode) = *self; let mut li_vn_mode = 0; li_vn_mode |= (li as u8) << 6; li_vn_mode |= vn.0 << 3; li_vn_mode |= mode as u8; writer.write_u8(li_vn_mode)?; Ok(()) } } impl WriteToBytes for Packet { fn write_to_bytes<W: WriteBytesExt>(&self, mut writer: W) -> io::Result<()> { let li_vn_mode = (self.leap_indicator, self.version, self.mode); writer.write_bytes(li_vn_mode)?; writer.write_bytes(self.stratum)?; writer.write_i8(self.poll)?; writer.write_i8(self.precision)?; writer.write_bytes(self.root_delay)?; writer.write_bytes(self.root_dispersion)?; writer.write_bytes(self.reference_id)?; writer.write_bytes(self.reference_timestamp)?; writer.write_bytes(self.origin_timestamp)?; writer.write_bytes(self.receive_timestamp)?; writer.write_bytes(self.transmit_timestamp)?; Ok(()) } } // Reader implementations. impl<R> ReadBytes for R where R: ReadBytesExt, { fn read_bytes<P: ReadFromBytes>(&mut self) -> io::Result<P> { P::read_from_bytes(self) } } impl ReadFromBytes for ShortFormat { fn read_from_bytes<R: ReadBytesExt>(mut reader: R) -> io::Result<Self> { let seconds = reader.read_u16::<BE>()?; let fraction = reader.read_u16::<BE>()?; let short_format = ShortFormat { seconds, fraction }; Ok(short_format) } } impl ReadFromBytes for TimestampFormat { fn read_from_bytes<R: ReadBytesExt>(mut reader: R) -> io::Result<Self> { let seconds = reader.read_u32::<BE>()?; let fraction = reader.read_u32::<BE>()?; let timestamp_format = TimestampFormat { seconds, fraction }; Ok(timestamp_format) } } impl ReadFromBytes for DateFormat { fn read_from_bytes<R: ReadBytesExt>(mut reader: R) -> io::Result<Self> { let era_number = reader.read_i32::<BE>()?; let era_offset = reader.read_u32::<BE>()?; let fraction = reader.read_u64::<BE>()?; let date_format = DateFormat { era_number, era_offset, fraction }; Ok(date_format) } } impl ReadFromBytes for Stratum { fn read_from_bytes<R: ReadBytesExt>(mut reader: R) -> io::Result<Self> { let stratum = Stratum(reader.read_u8()?); Ok(stratum) } } impl ReadFromBytes for (LeapIndicator, Version, Mode) { fn read_from_bytes<R: ReadBytesExt>(mut reader: R) -> io::Result<Self> { let li_vn_mode = reader.read_u8()?; let li_u8 = li_vn_mode >> 6; let vn_u8 = (li_vn_mode >> 3) & 0b111; let mode_u8 = li_vn_mode & 0b111; let li = match LeapIndicator::try_from(li_u8).ok() { Some(li) => li, None => { let err_msg = "unknown leap indicator"; return Err(io::Error::new(io::ErrorKind::InvalidData, err_msg)); }, }; let vn = Version(vn_u8); let mode = match Mode::try_from(mode_u8).ok() { Some(mode) => mode, None => { let err_msg = "unknown association mode"; return Err(io::Error::new(io::ErrorKind::InvalidData, err_msg)); }, }; Ok((li, vn, mode)) } } impl ReadFromBytes for Packet { fn read_from_bytes<R: ReadBytesExt>(mut reader: R) -> io::Result<Self> { let (leap_indicator, version, mode) = reader.read_bytes()?; let stratum = reader.read_bytes::<Stratum>()?; let poll = reader.read_i8()?; let precision = reader.read_i8()?; let root_delay = reader.read_bytes()?; let root_dispersion = reader.read_bytes()?; let reference_id = { let u = reader.read_u32::<BE>()?; if stratum == Stratum::PRIMARY { match PrimarySource::try_from(u) { Ok(src) => ReferenceIdentifier::PrimarySource(src), Err(_) => match KissOfDeath::try_from(u) { Ok(kod) => ReferenceIdentifier::KissOfDeath(kod), Err(_) => { let err_msg = "unknown reference id"; return Err(io::Error::new(io::ErrorKind::InvalidData, err_msg)); } }, } } else if stratum.is_secondary() { let arr = be_u32_to_bytes(u); ReferenceIdentifier::SecondaryOrClient(arr) } else { let err_msg = "unsupported stratum"; return Err(io::Error::new(io::ErrorKind::InvalidData, err_msg)); } }; let reference_timestamp = reader.read_bytes()?; let origin_timestamp = reader.read_bytes()?; let receive_timestamp = reader.read_bytes()?; let transmit_timestamp = reader.read_bytes()?; Ok(Packet { leap_indicator, version, mode, stratum, poll, precision, root_delay, root_dispersion, reference_id, reference_timestamp, origin_timestamp, receive_timestamp, transmit_timestamp, }) } } // Manual default implementations. impl Default for LeapIndicator { fn default() -> Self { LeapIndicator::NoWarning } } // Display implementations. impl fmt::Display for PrimarySource { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { let bytes = self.bytes(); let s = String::from_utf8_lossy(&bytes); write!(f, "{}", s) } } // Utility functions. fn be_u32_to_bytes(u: u32) -> [u8; 4] { [ (u >> 24 & 0xff) as u8, (u >> 16 & 0xff) as u8, (u >> 8 & 0xff) as u8, (u & 0xff) as u8, ] }