Struct etherparse::TcpHeader

pub struct TcpHeader {
    pub source_port: u16,
    pub destination_port: u16,
    pub sequence_number: u32,
    pub acknowledgment_number: u32,
    pub ns: bool,
    pub fin: bool,
    pub syn: bool,
    pub rst: bool,
    pub psh: bool,
    pub ack: bool,
    pub urg: bool,
    pub ece: bool,
    pub cwr: bool,
    pub window_size: u16,
    pub checksum: u16,
    pub urgent_pointer: u16,
    // some fields omitted
}

TCP header according to rfc 793.

Field descriptions copied from RFC 793 page 15++

Fields

source_port: u16

The source port number.

destination_port: u16

The destination port number.

sequence_number: u32

The sequence number of the first data octet in this segment (except when SYN is present).

If SYN is present the sequence number is the initial sequence number (ISN) and the first data octet is ISN+1. [copied from RFC 793, page 16]

acknowledgment_number: u32

If the ACK control bit is set this field contains the value of the next sequence number the sender of the segment is expecting to receive.

Once a connection is established this is always sent.

ns: bool

ECN-nonce - concealment protection (experimental: see RFC 3540)

fin: bool

No more data from sender

syn: bool

Synchronize sequence numbers

rst: bool

Reset the connection

psh: bool

Push Function

ack: bool

Acknowledgment field significant

urg: bool

Urgent Pointer field significant

ece: bool

ECN-Echo (RFC 3168)

cwr: bool

Congestion Window Reduced (CWR) flag

This flag is set by the sending host to indicate that it received a TCP segment with the ECE flag set and had responded in congestion control mechanism (added to header by RFC 3168).

window_size: u16

The number of data octets beginning with the one indicated in the acknowledgment field which the sender of this segment is willing to accept.

checksum: u16

Checksum (16 bit one's complement) of the pseudo ip header, this tcp header and the payload.

urgent_pointer: u16

This field communicates the current value of the urgent pointer as a positive offset from the sequence number in this segment.

The urgent pointer points to the sequence number of the octet following the urgent data. This field is only be interpreted in segments with the URG control bit set.

Methods

impl TcpHeader

pub fn new(
    source_port: u16,
    destination_port: u16,
    sequence_number: u32,
    window_size: u16
) -> TcpHeader

Creates a TcpHeader with the given values and the rest initialized with default values.

pub fn data_offset(&self) -> u8

The number of 32 bit words in the TCP Header.

This indicates where the data begins. The TCP header (even one including options) is an integral number of 32 bits long.

pub fn header_len(&self) -> u16

Returns the length of the header including the options.

pub fn options_len(&self) -> usize

Returns the options size in bytes based on the currently set data_offset. Returns None if the data_offset is smaller then the minimum size or bigger then the maximum supported size.

pub fn options(&self) -> &[u8]

Returns a slice containing the options of the header (size is determined via the data_offset field.

pub fn set_options(
    &mut self,
    options: &[TcpOptionElement]
) -> Result<(), TcpOptionWriteError>

Sets the options (overwrites the current options) or returns an error when there is not enough space.

pub fn set_options_raw(
    &mut self,
    data: &[u8]
) -> Result<(), TcpOptionWriteError>

Sets the options to the data given.

Important traits for TcpOptionsIterator<'a>

impl<'a> Iterator for TcpOptionsIterator<'a> type Item = Result<TcpOptionElement, TcpOptionReadError>;

pub fn options_iterator(&self) -> TcpOptionsIterator

Returns an iterator that allows to iterate through all known TCP header options.

pub fn read_from_slice(slice: &[u8]) -> Result<(TcpHeader, &[u8]), ReadError>

Reads a tcp header from a slice

pub fn read<T: Read + Sized>(reader: &mut T) -> Result<TcpHeader, ReadError>

Read a tcp header from the current position

pub fn write<T: Write + Sized>(&self, writer: &mut T) -> Result<(), Error>

Write the tcp header to a stream (does NOT calculate the checksum).

pub fn calc_checksum_ipv4(
    &self,
    ip_header: &Ipv4Header,
    payload: &[u8]
) -> Result<u16, ValueError>

Calculates the upd header checksum based on a ipv4 header and returns the result. This does NOT set the checksum.

pub fn calc_checksum_ipv4_raw(
    &self,
    source_ip: [u8; 4],
    destination_ip: [u8; 4],
    payload: &[u8]
) -> Result<u16, ValueError>

Calculates the checksum for the current header in ipv4 mode and returns the result. This does NOT set the checksum.

pub fn calc_checksum_ipv6(
    &self,
    ip_header: &Ipv6Header,
    payload: &[u8]
) -> Result<u16, ValueError>

Calculates the upd header checksum based on a ipv6 header and returns the result. This does NOT set the checksum..

pub fn calc_checksum_ipv6_raw(
    &self,
    source: &[u8; 16],
    destination: &[u8; 16],
    payload: &[u8]
) -> Result<u16, ValueError>

Calculates the checksum for the current header in ipv6 mode and returns the result. This does NOT set the checksum.

Trait Implementations

impl Default for TcpHeader

fn default() -> TcpHeader

Returns the "default value" for a type.

impl Clone for TcpHeader

fn clone(&self) -> TcpHeader

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Eq for TcpHeader

impl PartialEq<TcpHeader> for TcpHeader

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

This method tests for self and other values to be equal, and is used by ==.

#[must_use]

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

This method tests for !=.

impl Debug for TcpHeader

fn fmt(&self, fotmatter: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.