Struct BufferedReassembler 

pub struct BufferedReassembler { /* private fields */ }

Available on crate feature reassembler only.

Built-in: drop OOO segments, accumulate in-order bytes into a Vec<u8> per direction. Drain via take.

Sync, no channel dep. Users who want a channel send via std::sync::mpsc themselves, or use netring’s TokioChannelReassembler for tokio integration.

Optionally bounded via with_max_buffer. When the cap is reached the OverflowPolicy decides whether to rotate bytes out (sliding window) or poison the reassembler so the driver can tear the flow down on the next tick.

Implementations

impl BufferedReassembler

pub fn new() -> Self

pub fn with_max_buffer(self, max_bytes: usize) -> Self

Set a maximum in-flight buffer size in bytes. When new in-order segments would push buffered_len() past this cap, the configured OverflowPolicy kicks in.

Default policy is OverflowPolicy::SlidingWindow. Pair with with_overflow_policy to switch to OverflowPolicy::DropFlow for framed binary protocols.

pub fn with_overflow_policy(self, policy: OverflowPolicy) -> Self

Override the overflow policy. Has no effect unless with_max_buffer is also called.

pub fn with_high_watermark_threshold(self, percent: u8) -> Self

Fire a crate::AnomalyKind::ReassemblerHighWatermark anomaly when buffer occupancy crosses percent % of max_buffer from below — once per crossing (debounced; occupancy must drop back below before the next event re-arms). Default: off.

No effect unless with_max_buffer is also set. Values outside 1..=100 are clamped.

pub fn take(&mut self) -> Vec<u8>

Drain accumulated in-order bytes, leaving the buffer empty. expected_seq is preserved so subsequent in-order segments keep accumulating. Also re-arms the high-watermark threshold (if configured): once drained, the next time occupancy climbs back above the threshold counts as a fresh crossing.

pub fn dropped_segments(&self) -> u64

Number of segments dropped because they were out of order.

pub fn bytes_dropped_oversize(&self) -> u64

Number of payload bytes dropped because the per-side buffer cap was exceeded. Zero when no cap is set or when the cap has not yet been hit.

pub fn buffered_len(&self) -> usize

Bytes currently buffered (not yet drained).

pub fn is_poisoned(&self) -> bool

True after an OverflowPolicy::DropFlow overflow. The driver checks this once per tick; true triggers an Ended { reason: BufferOverflow } event for the flow.

pub fn high_watermark(&self) -> u64

Peak buffer occupancy ever observed for this reassembler. Updated on every append_with_cap call, reflecting post-rotation state under OverflowPolicy::SlidingWindow. Survives take — useful for tuning crate::FlowTrackerConfig::max_reassembler_buffer.

pub fn retransmits(&self) -> u64

Number of TCP segments classified as retransmits on this side — seq + len <= expected_seq. Distinct from dropped_segments, which counts strictly-out-of-order segments ahead of expected_seq. New in 0.5.0.

impl BufferedReassembler

pub fn high_watermark_crossings(&self) -> u64

Running count of below→above transitions of the configured high-watermark threshold. Zero when no threshold is set.

Trait Implementations

impl Debug for BufferedReassembler

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

Formats the value using the given formatter.

impl Default for BufferedReassembler

fn default() -> BufferedReassembler

Returns the “default value” for a type.

impl Reassembler for BufferedReassembler

fn segment(&mut self, seq: u32, payload: &[u8], ts: Timestamp)

New segment arrived in this direction.

fn dropped_segments(&self) -> u64

Number of TCP segments dropped because they arrived out of order for this side. Default: 0.

fn bytes_dropped_oversize(&self) -> u64

Number of payload bytes dropped because the per-side buffer cap was exceeded. Default: 0.

fn is_poisoned(&self) -> bool

True after a fatal-style overflow (e.g. crate::OverflowPolicy::DropFlow). The driver checks this once per tick; true triggers synthesis of an Ended { reason: BufferOverflow } event for the flow. Default: false.

fn high_watermark(&self) -> u64

Peak in-flight buffer occupancy ever observed for this side. Default: 0 (custom reassemblers may not track this).

fn bytes_in_flight(&self) -> u64

Bytes currently buffered, awaiting parser consumption. Default: 0. Mirrors the contract of Self::high_watermark — only meaningful for impls that actually buffer bytes.

fn high_watermark_crossings(&self) -> u64

Running count of below→above transitions of the configured high-watermark threshold (see [BufferedReassembler:: with_high_watermark_threshold]). Default: 0. The driver uses per-tick deltas of this counter to emit crate::AnomalyKind::ReassemblerHighWatermark events without spamming on repeated above-threshold ticks.

fn high_watermark_threshold(&self) -> Option<(u64, u8)>

Some((cap, percent)) when a high-watermark threshold is configured; None otherwise. Lets the driver enrich crate::AnomalyKind::ReassemblerHighWatermark events with the cap and threshold percent at emission time. Default: None.

fn retransmits(&self) -> u64

Number of TCP segments classified as retransmits — re-deliveries of bytes the reassembler has already accounted for (seq + len <= expected_seq). New in 0.5.0; default 0.

fn current_bytes(&self) -> u64

Current live byte occupancy of the reassembler — bytes in the ready buffer plus any OOO pending. This is the hook a future global-memcap enforcement layer (see crate::FlowTrackerConfig::reassembly_memcap) reads to sum cross-flow usage.

fn fin(&mut self)

FIN observed in this direction. Default: no-op.

fn rst(&mut self)

RST observed in this direction (or session aborted). Default: no-op.

fn on_duplicate(&mut self, _seq: u32, _payload: &[u8], _ts: Timestamp)

Hook called when a segment is classified as a retransmit rather than appended to the buffer. Default no-op. Custom reassemblers can use this to drive RTT estimators, retransmit-rate metrics, etc. Called by BufferedReassembler for each classified retransmit; not called for fresh or OOO segments.

fn rexmit_inconsistencies(&self) -> u64

Running count of retransmits whose bytes differ from what the reassembler previously saw for the overlapping sequence range — the classic Ptacek-Newsham TCP overlap evasion IOC (cf. Zeek’s rexmit_inconsistency). Default 0 for implementations that don’t retain enough history to detect the divergence.