Struct TcpFlags 

pub struct TcpFlags {
    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 ns: bool,
}

TCP flags structure (9 bits).

Bit layout (from MSB to LSB in the 16-bit flags/reserved field):

• NS (Nonce Sum) - ECN nonce concealment
• CWR (Congestion Window Reduced)
• ECE (ECN-Echo)
• URG (Urgent)
• ACK (Acknowledgment)
• PSH (Push)
• RST (Reset)
• SYN (Synchronize)
• FIN (Finish)

Scapy uses the string “FSRPAUECN” for flags (reversed order).

Fields

fin: bool

FIN - No more data from sender

syn: bool

SYN - Synchronize sequence numbers

rst: bool

RST - Reset the connection

psh: bool

PSH - Push function

ack: bool

ACK - Acknowledgment field significant

urg: bool

URG - Urgent pointer field significant

ece: bool

ECE - ECN-Echo (RFC 3168)

cwr: bool

CWR - Congestion Window Reduced (RFC 3168)

ns: bool

NS - ECN-nonce concealment protection (RFC 3540)

Implementations

impl TcpFlags

pub const NONE: Self

No flags set

pub const S: Self

SYN flag only (connection initiation)

pub const SA: Self

SYN+ACK flags (connection acknowledgment)

pub const A: Self

ACK flag only

pub const FA: Self

FIN+ACK flags (connection termination)

pub const R: Self

RST flag only (connection reset)

pub const RA: Self

RST+ACK flags

pub const PA: Self

PSH+ACK flags (data push)

pub const FIN_BIT: u16 = 0x001

Flag bit positions (in the 9-bit flags field)

pub const SYN_BIT: u16 = 0x002

pub const RST_BIT: u16 = 0x004

pub const PSH_BIT: u16 = 0x008

pub const ACK_BIT: u16 = 0x010

pub const URG_BIT: u16 = 0x020

pub const ECE_BIT: u16 = 0x040

pub const CWR_BIT: u16 = 0x080

pub const NS_BIT: u16 = 0x100

pub fn from_u16(value: u16) -> Self

Create flags from a raw 16-bit value (data offset + reserved + flags).

The flags are in the lower 9 bits (with NS in bit 8 of the high byte).

pub fn from_byte(byte: u8) -> Self

Create flags from just the flags byte (lower 8 bits).

pub fn from_bytes(hi: u8, lo: u8) -> Self

Create flags from two bytes (data_offset_reserved + flags).

pub fn to_u16(self) -> u16

Convert to a raw 9-bit value.

pub fn to_byte(self) -> u8

Convert to the lower flags byte (without NS).

pub fn ns_bit(self) -> u8

Get the NS bit for the high byte.

pub fn from_str(s: &str) -> Self

Create flags from a string like “S”, “SA”, “FA”, “PA”, “R”, etc. Uses Scapy’s “FSRPAUECN” convention.

pub fn is_syn(&self) -> bool

Check if this is a SYN packet (SYN set, ACK not set).

pub fn is_syn_ack(&self) -> bool

Check if this is a SYN-ACK packet.

pub fn is_ack(&self) -> bool

Check if this is a pure ACK packet.

pub fn is_fin(&self) -> bool

Check if this is a FIN packet.

pub fn is_rst(&self) -> bool

Check if this is a RST packet.

pub fn has_ecn(&self) -> bool

Check if ECN is enabled (ECE or CWR set).

pub fn is_empty(&self) -> bool

Check if any flag is set.

pub fn count(&self) -> u8

Count how many flags are set.

Trait Implementations

impl BitAnd for TcpFlags

type Output = TcpFlags

The resulting type after applying the & operator.

fn bitand(self, rhs: Self) -> Self::Output

Performs the & operation.

impl BitAndAssign for TcpFlags

fn bitand_assign(&mut self, rhs: Self)

Performs the &= operation.

impl BitOr for TcpFlags

type Output = TcpFlags

The resulting type after applying the | operator.

fn bitor(self, rhs: Self) -> Self::Output

Performs the | operation.

impl BitOrAssign for TcpFlags

fn bitor_assign(&mut self, rhs: Self)

Performs the |= operation.

impl Clone for TcpFlags

fn clone(&self) -> TcpFlags

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TcpFlags

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

Formats the value using the given formatter.

impl Default for TcpFlags

fn default() -> TcpFlags

Returns the “default value” for a type.

impl Display for TcpFlags

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

Formats the value using the given formatter.

impl From<&str> for TcpFlags

fn from(s: &str) -> Self

Converts to this type from the input type.

impl From<TcpFlags> for u16

fn from(flags: TcpFlags) -> Self

Converts to this type from the input type.

impl From<TcpFlags> for u8

fn from(flags: TcpFlags) -> Self

Converts to this type from the input type.

impl From<u16> for TcpFlags

fn from(value: u16) -> Self

Converts to this type from the input type.

impl From<u8> for TcpFlags

fn from(value: u8) -> Self

Converts to this type from the input type.

impl Hash for TcpFlags

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 TcpFlags

fn eq(&self, other: &TcpFlags) -> 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 Copy for TcpFlags

impl Eq for TcpFlags

impl StructuralPartialEq for TcpFlags