Struct Packet

pub struct Packet {

    pub leap_indicator: LeapIndicator,
    pub version: Version,
    pub mode: Mode,
    pub stratum: Stratum,
    pub poll: i8,
    pub precision: i8,
    pub root_delay: ShortFormat,
    pub root_dispersion: ShortFormat,
    pub reference_id: ReferenceIdentifier,
    pub reference_timestamp: TimestampFormat,
    pub origin_timestamp: TimestampFormat,
    pub receive_timestamp: TimestampFormat,
    pub transmit_timestamp: TimestampFormat,
}

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).

+-----------+------------+-----------------------+
| 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.

 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)                         |
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Fields

leap_indicator: LeapIndicator

version: Version

mode: Mode

stratum: Stratum

poll: i8

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.

precision: 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.

root_delay: ShortFormat

Total round-trip delay to the reference clock, in NTP short format.

root_dispersion: ShortFormat

Total dispersion to the reference clock, in NTP short format.

reference_id: ReferenceIdentifier

reference_timestamp: TimestampFormat

Time when the system clock was last set or corrected.

origin_timestamp: TimestampFormat

Time at the client when the request departed for the server.

receive_timestamp: TimestampFormat

Time at the server when the request arrived from the client.

transmit_timestamp: TimestampFormat

Time at the server when the response left for the client.

Trait Implementations

impl Clone for Packet

fn clone(&self) -> Packet

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl ConstPackedSizeBytes for Packet

const PACKED_SIZE_BYTES: usize = 48usize

impl Debug for Packet

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for Packet

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Packet

fn eq(&self, other: &Packet) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl ReadFromBytes for Packet

fn read_from_bytes<R: ReadBytesExt>(reader: R) -> Result<Self>

Read the command from bytes.

impl WriteToBytes for Packet

fn write_to_bytes<W: WriteBytesExt>(&self, writer: W) -> Result<()>

Write the command to bytes.

impl Copy for Packet

impl Eq for Packet

impl StructuralPartialEq for Packet