keyexchange

package
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 Go to latest Published: May 8, 2026 License: AGPL-3.0 Imports: 18 Imported by: 0

Documentation

Overview

Package keyexchange is L5 — establishes the per-peer AEAD session key (with optional Ed25519 authentication of identity).

The Manager owns:

  • pendingRekey map[uint32]*PendingRekeyState — tracks key exchanges we sent and are awaiting a reply on. Drives the retransmit loop.
  • peerPubKeys map[uint32]ed25519.PublicKey — cached peer Ed25519 pubkeys (filled from the verifyFunc callback).
  • lastInboundDecrypt map[uint32]time.Time — used by the handleAuthKeyExchange "stale reply" gate.
  • the rekey retransmit goroutine (Loop).

It owns the L5 Store — the per-peer Crypto registry. L6 (envelope) imports Store to look up keys when wrapping/unwrapping AEAD frames.

Per docs/architecture/01-LAYERS.md L5: 

Role: establish the per-peer AEAD session key (with optional
  Ed25519 authentication of identity).
Owns: pendingRekey, peerPubKeys cache, the rekeyRetransmitLoop
  goroutine, AND (post T5.x-followup) the per-peer Crypto Store +
  replay window + salvage ring + decryptFailCount.
Consumes: L1, L2 (sends bootstrap frames; first auth-key-exchange
  is the only frame that bypasses L6 envelope), L3 (signs/verifies),
  L4 (routes the frame).
Exposes: Establish(peer) → SessionKey, RekeyTrigger(peer),
  key-install events.

Per docs/architecture/03-INVARIANTS.md §3 (lock graph): rkPendingMu is a LEAF lock — never held while taking any TunnelManager mutex. All callers obey this by reading state under rkPendingMu, releasing, then mutating tm-side state in a separate critical section.

Per docs/architecture/03-INVARIANTS.md §9 (horizontal-incest): L6 → L5 is the canonical downward import. keyexchange/ MUST NOT import envelope/ — that would be upward and contradict 01-LAYERS.md §"Layer dependencies".

Index

Constants

View Source 
const (
	// RekeyRetransmitInterval is how long we wait for an inbound encrypted
	// packet to confirm the peer received our key_exchange. After this we
	// retransmit on the assumption either our key_exchange or the peer's
	// reply was dropped.
	RekeyRetransmitInterval = 4 * time.Second

	// MaxRekeyAttempts caps the retransmit loop. The first send + this
	// many retries = 1 + MaxRekeyAttempts total attempts. After that we
	// give up — peer is presumed gone.
	MaxRekeyAttempts = 5

	// KeyExchangeReplyStaleThreshold: when an auth_key_exchange arrives
	// and we already have crypto for the peer with no inbound traffic in
	// this window, reply with our key_exchange too (in case our previous
	// reply was dropped). Loosens handleAuthKeyExchange's "send back" gate.
	KeyExchangeReplyStaleThreshold = 6 * time.Second
)

Tunable timing constants. Frozen wire-adjacent behavior — changing these affects observable retransmit cadence + stale-reply gating.

View Source 
const DecryptFailDropGrace = 3 * time.Second

DecryptFailDropGrace is the minimum age a Crypto must reach before repeated decrypt failures can drop it. Set above the typical relay RTT (≤200 ms) plus a comfortable margin: stale ciphertext from before the peer's last rekey takes ~1 RTT to drain, but if salvage replay is in play it can stretch slightly. 3 s covers worst-case drain without holding a genuinely diverged session for long.

View Source 
const DecryptFailDropThreshold = 5

DecryptFailDropThreshold is how many consecutive AEAD-authentication failures from a single peer trigger a full Crypto drop + re-handshake. Sized to swallow a small burst of legitimate packet corruption (kernel buffer overruns, mid-flight key rotation crossing the wire) while still recovering from peer-side AEAD-key divergence within a few seconds — a daemon restart on either side cycles the peer through a fresh handshake; this is the "equivalent recovery without restarting" path.

Lives on L5 with the per-peer state it gates rather than on L6 framing, because the drop decision uses Crypto.CreatedAt (key-install time, an L5 concept) and Crypto.DecryptFailCount (per-peer state).

View Source 
const HKDFInfo = "pilot-tunnel-v1"

HKDFInfo is the frozen HKDF info string used to derive AEAD keys from the X25519 shared secret. Changing it would break wire compatibility with every existing peer — DO NOT change.

View Source 
const MaxCryptoPeers = 16384

MaxCryptoPeers caps the crypto map for unauth key-exchange insertions. HandleAuthFrame is implicitly bounded by the registry-verified pubkey lookup, but HandleUnauthFrame accepts any peerNodeID and performs an X25519 scalar multiplication per packet. Without a cap, a peer spraying unauth key-exchange frames with random node IDs can grow the map to 2^32 entries while also burning CPU on derivation. Set high enough that real deployments never hit it.

Lives on L5 with the per-peer Store rather than as a free constant in L6 framing — the cap is a property of key-state ownership.

View Source 
const ReplayWindowSize = 256

ReplayWindowSize is the number of nonces tracked in the sliding window bitmap for replay detection (H8 fix). Nonces within [maxNonce-ReplayWindowSize, maxNonce] are tracked; nonces below the window are rejected.

Per-peer state — owned with the key, hence on L5 (keyexchange) rather than L6 (envelope).

View Source 
const SalvageMaxAge = 5 * time.Second

SalvageMaxAge is how far back we replay sends after a rekey. The rekey round-trip itself is ~1 RTT plus the rate-limit window (3 s); 5 s gives margin for slow handshakes under loss.

View Source 
const SalvageMaxEntries = 4

SalvageMaxEntries bounds memory + replay-storm size on rekey. Originally 32, but a 32-frame burst replayed on rekey caused receiver-side nonce confusion (concurrent dataexchange retransmits filling salvage + out-of-order delivery on the wire). 4 covers the typical "send-message + a couple of retries" without overwhelming the receiver. Memory at max: 4 × ~1500 B = 6 KiB / peer, ~6 MiB across maxCryptoPeers (1024).

Variables

View Source 
var ErrNoKey = errors.New("keyexchange: no key installed for peer")

ErrNoKey is returned when no Crypto is installed for a peer (encrypt-side: no key to wrap with; decrypt-side: nothing to unwrap with). Caller's responsibility to trigger a rekey request.

View Source 
var ErrNotReady = errors.New("keyexchange: crypto installed but not ready")

ErrNotReady is returned when a Crypto exists but is not yet marked Ready (key exchange in progress).

Functions

This section is empty.

Types

type Crypto 

type Crypto struct {
	AEAD        cipher.AEAD
	Nonce       uint64  // monotonic send counter (atomic)
	NoncePrefix [4]byte // random prefix for nonce domain separation

	// Replay detection (H8 fix): sliding window bitmap instead of simple
	// high-water mark.
	ReplayMu     sync.Mutex
	MaxRecvNonce uint64                        // highest nonce received
	ReplayBitmap [ReplayWindowSize / 64]uint64 // bitmap for nonces in [max-windowSize, max]

	Ready         bool     // true once key exchange is complete
	Authenticated bool     // true if peer proved Ed25519 identity
	PeerX25519Key [32]byte // peer's X25519 public key (for detecting rekeying)

	// DecryptFailCount tracks consecutive AEAD authentication failures
	// since the last successful decrypt. Older-version peer daemons drift
	// into a state where their derived AEAD key no longer matches ours
	// (likely a session-id or info-string mismatch in HKDF), at which
	// point every encrypted packet from the peer fails with "cipher:
	// message authentication failed". Once this counter exceeds
	// DecryptFailDropThreshold the daemon drops this Crypto entirely
	// and triggers a fresh key exchange — equivalent to a daemon-restart
	// recovery without actually restarting. Reset to 0 on any successful
	// decrypt.
	DecryptFailCount int

	// CreatedAt is when this Crypto was installed. Used by L5's
	// handleAuthKeyExchange to decide between preserving existing state
	// (fresh handshake retransmit/reply within seconds) and resetting it
	// (long-lived peer's own state desynced — e.g. older-version daemon
	// rotated its send counter without rotating X25519 keys, which
	// otherwise leaves us with a high MaxRecvNonce that rejects the
	// peer's resumed packets as replays). Also gates the rc5 grace
	// period (see DecryptFailDropGrace).
	CreatedAt time.Time

	// P1-010 desync salvage: ring buffer of recent plaintext sent with
	// this key. On a peer-initiated rekey, these are re-encrypted with
	// the new key and re-sent — recovering the data that was vaporized
	// when the peer dropped our stale-keyed frames.
	SalvageMu sync.Mutex
	Salvage   []SalvageEntry
}

Crypto holds per-peer encryption state. Created by L5 (DeriveSecret) after key derivation; mutated by L6 on every encrypt/decrypt; cleared on rekey or peer drop.

Per docs/architecture/03-INVARIANTS.md §3 (lock graph): Crypto's ReplayMu and SalvageMu are LEAF locks. They are never nested with any TunnelManager-side mutex (tm.mu, tm.rkPendingMu, etc.). Methods on Crypto must not acquire any external lock while holding them.

Ownership lives on L5 (keyexchange) per docs/architecture/01-LAYERS.md: L6 'Consumes: ... L5 (key state)' — the envelope is a downward consumer of L5's per-peer state, not its owner.

func (*Crypto) CheckAndRecordNonce 

func (c *Crypto) CheckAndRecordNonce(counter uint64) bool

CheckAndRecordNonce returns true if the nonce is valid (not replayed, not too old). Must be called with c.ReplayMu held.

Note on nonce wraparound: the counter is uint64, so it wraps after 2^64 packets. At 1 billion packets/sec this takes ~585 years — purely theoretical. If a connection ever approaches this limit, rekeying (new secure handshake) resets the counter naturally.

func (*Crypto) SetReplayBit 

func (c *Crypto) SetReplayBit(counter uint64)

SetReplayBit sets the replay-window bit corresponding to counter. Must be called with c.ReplayMu held.

func (*Crypto) UndoReplayBit 

func (c *Crypto) UndoReplayBit(counter uint64)

UndoReplayBit clears the bit set by a prior SetReplayBit. Used by L6 when AEAD-Open fails to roll back the speculative bookkeeping — without this, a flood of failed-decrypt frames would wedge legitimate later packets out of the replay window. Must be called with c.ReplayMu held.

type EventPublisher 

type EventPublisher func(topic string, payload map[string]any)

EventPublisher is the daemon's event-bus surface; nil-safe. Provided by tunnel.go via a closure over tm.publishEvent.

type FrameSender 

type FrameSender func(peerNodeID uint32, addr *net.UDPAddr, frame []byte) error

FrameSender is L2's contribution to L5: ship a raw UDP frame to a peer (relay-aware). tunnel.go satisfies this with writeFrame.

When sub-pass 4 extracts L2, this becomes an L2 interface; for now the daemon supplies a closure capturing tm.writeFrame.

type Manager 

type Manager struct {
	// contains filtered or unexported fields
}

Manager owns the L5 state.

func New 

func New(store *Store) *Manager

New returns a fresh Manager. The Manager installs into store; pass store=nil to have New construct one. The same Store pointer is imported by L6 (envelope) for AEAD encrypt/decrypt operations.

func (*Manager) BuildAuthFrame 

func (m *Manager) BuildAuthFrame() []byte

BuildAuthFrame builds an authenticated key exchange frame. Returns nil if our X25519 pubkey or Ed25519 identity is unavailable.

Layout: [PILA(4)][nodeID(4 BE)][X25519 pubkey(32)][Ed25519 pubkey(32)][signature(64)] = 136 bytes.

func (*Manager) BuildUnauthFrame 

func (m *Manager) BuildUnauthFrame() []byte

BuildUnauthFrame builds an unauthenticated key exchange frame. Returns nil if our X25519 pubkey is unavailable.

Layout: [PILK(4)][nodeID(4 BE)][X25519 pubkey(32)] = 40 bytes.

func (*Manager) ClearPendingRekey 

func (m *Manager) ClearPendingRekey(peerNodeID uint32)

ClearPendingRekey cancels any in-flight retransmit tracking for peerNodeID. Called from Handle*Frame paths (we received their key exchange, so we no longer need to keep hammering them with ours). Does NOT clear rekeyGaveUp — receiving a key exchange is not proof of bidirectional reachability; only a successful decrypt is. Clearing rekeyGaveUp here caused the bounce to re-arm whenever a peer with no cooldown fix kept sending us key exchanges.

func (*Manager) ClearRekeyGaveUp 

func (m *Manager) ClearRekeyGaveUp(peerNodeID uint32)

ClearRekeyGaveUp lifts the post-give-up cooldown for peerNodeID. Must only be called after a successful decrypt — proof that bidirectional crypto works.

func (*Manager) DeriveSecret 

func (m *Manager) DeriveSecret(peerPubKeyBytes []byte) (*Crypto, error)

DeriveSecret computes a shared AES-256-GCM cipher from the peer's X25519 public key, returning a fresh Crypto ready to be installed.

Uses HKDF-SHA256 (info = "pilot-tunnel-v1", per HKDFInfo) to derive the AEAD key from the X25519 shared secret. Intermediate key material is zeroed before return (H4 fix).

func (*Manager) GetPeerPubKey 

func (m *Manager) GetPeerPubKey(nodeID uint32) (ed25519.PublicKey, error)

GetPeerPubKey returns the cached Ed25519 public key for a peer, fetching from the registry (via verifyFunc) on cache miss.

func (*Manager) HandleAuthFrame 

func (m *Manager) HandleAuthFrame(data []byte, from *net.UDPAddr, fromRelay bool) bool

HandleAuthFrame processes an authenticated key exchange packet (PILA).

Frame layout (after 4-byte magic stripped by caller): 

[4 nodeID][32 X25519 pubkey][32 Ed25519 pubkey][64 Ed25519 signature]

The signature is over: "auth"(4) || nodeID(4 BE) || X25519-pubkey(32). fromRelay indicates this was received via beacon relay — the PostInstallHook decides what to do with the peer-endpoint update.

Returns true if a Crypto was installed (or already-present-and-fresh crypto was kept), false on any reject path (signature mismatch, missing identity, encryption disabled, malformed input).

func (*Manager) HandleUnauthFrame 

func (m *Manager) HandleUnauthFrame(data []byte, from *net.UDPAddr, fromRelay bool) bool

HandleUnauthFrame processes an unauthenticated key exchange packet (PILK).

Frame layout (after 4-byte magic stripped by caller): 

[4 nodeID][32 X25519 pubkey]

If we have an identity AND the peer has a registered pubkey, reject the unauthenticated exchange and reply with our authenticated frame instead.

func (*Manager) HasIdentity 

func (m *Manager) HasIdentity() bool

HasIdentity is a fast path used to gate auth/unauth frame selection.

func (*Manager) HasPeerPubKey 

func (m *Manager) HasPeerPubKey(nodeID uint32) bool

HasPeerPubKey reports whether the cache currently holds an entry for nodeID.

func (*Manager) Identity 

func (m *Manager) Identity() *crypto.Identity

Identity returns the currently-set identity (or nil).

func (*Manager) InboundDecryptStale 

func (m *Manager) InboundDecryptStale(peerNodeID uint32) bool

InboundDecryptStale returns true if we haven't successfully decrypted any packet from peerNodeID within the staleness window.

func (*Manager) InjectPendingRekeyForTest 

func (m *Manager) InjectPendingRekeyForTest(peerNodeID uint32, st *PendingRekeyState)

InjectPendingRekeyForTest sets a state directly. Test-only; production code never bypasses MarkPendingRekey.

func (*Manager) InvalidatePeerPubKey 

func (m *Manager) InvalidatePeerPubKey(nodeID uint32)

InvalidatePeerPubKey deletes a cache entry.

func (*Manager) LastInboundDecryptHas 

func (m *Manager) LastInboundDecryptHas(peerNodeID uint32) bool

LastInboundDecryptHas reports whether we've recorded any successful decrypt timestamp for the peer.

func (*Manager) Loop 

func (m *Manager) Loop(ctx context.Context)

Loop runs the rekey retransmit loop. It scans pendingRekey every RekeyRetransmitInterval, retransmits stale entries via SendKeyExchangeToNode, and gives up after MaxRekeyAttempts.

Cancel via ctx — typical wiring uses tunnel.done as the cancellation source through a tiny adapter goroutine.

func (*Manager) MarkPendingRekey 

func (m *Manager) MarkPendingRekey(peerNodeID uint32) bool

MarkPendingRekey records that we sent a key_exchange to peerNodeID and are awaiting confirmation. Idempotent — re-calls bump LastSentAt and Attempts but preserve FirstSentAt.

Returns false and is a no-op if the peer is within the rekeyGaveUpCooldown window, preventing an immediate restart of a just-failed rekey cycle.

func (*Manager) PeerInRekeyGaveUp 

func (m *Manager) PeerInRekeyGaveUp(peerNodeID uint32) bool

PeerInRekeyGaveUp reports whether peerNodeID is within the give-up cooldown. Used by the tunnel to skip queuing outbound packets for unreachable peers.

func (*Manager) PendingRekeyAttempts 

func (m *Manager) PendingRekeyAttempts(peerNodeID uint32) int

PendingRekeyAttempts returns the current attempts count (0 if not pending).

func (*Manager) PendingRekeyForTest 

func (m *Manager) PendingRekeyForTest(peerNodeID uint32) *PendingRekeyState

PendingRekeyForTest returns the live PendingRekeyState pointer (or nil) for a peer. Exposed so package-internal tests can inspect the FirstSentAt / LastSentAt timestamps without re-deriving them via the public counters. Acquires rkPendingMu briefly; safe for concurrent use.

func (*Manager) PendingRekeyHas 

func (m *Manager) PendingRekeyHas(peerNodeID uint32) bool

PendingRekeyHas reports whether an entry exists.

func (*Manager) PrivKey 

func (m *Manager) PrivKey() *ecdh.PrivateKey

PrivKey returns the local X25519 private key.

func (*Manager) PubKey 

func (m *Manager) PubKey() []byte

PubKey returns the local X25519 public key (32 bytes). May be nil if SetX25519Keys was never called.

func (*Manager) RecordInboundDecrypt 

func (m *Manager) RecordInboundDecrypt(peerNodeID uint32)

RecordInboundDecrypt updates the per-peer last-decrypt timestamp.

func (*Manager) RekeyRetransmitTick 

func (m *Manager) RekeyRetransmitTick()

RekeyRetransmitTick is the per-tick body of Loop, split out for direct testing without a real ticker. Iterates pendingRekey under rkPendingMu, releases it before invoking SendKeyExchangeToNode (which re-takes rkPendingMu via MarkPendingRekey — splitting the lock keeps rkPendingMu a true leaf).

func (*Manager) RemovePeer 

func (m *Manager) RemovePeer(nodeID uint32)

RemovePeer wipes per-peer L5 state (called from TunnelManager.RemovePeer).

func (*Manager) SendKeyExchangeToNode 

func (m *Manager) SendKeyExchangeToNode(peerNodeID uint32)

SendKeyExchangeToNode sends an authenticated key exchange if identity is available, otherwise falls back to unauthenticated.

This function carries the single annotated bootstrap-exception site (see the marker comment inside the body). After Stage 2 sub-pass 2, the canonical home for the marker is here in keyexchange/bootstrap.go; layers.yaml's bootstrap_exception.allowed_call_sites tracks this path.

func (*Manager) SetAddrLookup 

func (m *Manager) SetAddrLookup(f PeerAddrLookup)

SetAddrLookup wires the peer-address resolver.

func (*Manager) SetIdentity 

func (m *Manager) SetIdentity(id *crypto.Identity)

SetIdentity sets our Ed25519 identity for signing authenticated key exchanges. May be called concurrently with HandleAuthFrame / Send.

func (*Manager) SetLastInboundDecryptForTest 

func (m *Manager) SetLastInboundDecryptForTest(peerNodeID uint32, t time.Time)

SetLastInboundDecryptForTest writes a timestamp directly.

func (*Manager) SetLocalNodeIDFn 

func (m *Manager) SetLocalNodeIDFn(f func() uint32)

SetLocalNodeIDFn supplies the closure used to read our own node ID (atomic read living in the daemon).

func (*Manager) SetPeerPubKey 

func (m *Manager) SetPeerPubKey(nodeID uint32, pk ed25519.PublicKey)

SetPeerPubKey installs a cache entry directly. Used by handle paths after verifying a packet-carried Ed25519 pubkey against the registry.

func (*Manager) SetPeerVerifyFunc 

func (m *Manager) SetPeerVerifyFunc(f VerifyFunc)

SetPeerVerifyFunc sets the callback used to fetch a peer's Ed25519 public key from the registry on cache miss.

func (*Manager) SetPostInstallHook 

func (m *Manager) SetPostInstallHook(h PostInstallHook)

SetPostInstallHook wires the post-install daemon callback (peer endpoint bookkeeping, salvage replay, etc.).

func (*Manager) SetPublisher 

func (m *Manager) SetPublisher(p EventPublisher)

SetPublisher wires the daemon's event bus (nil-safe).

func (*Manager) SetSender 

func (m *Manager) SetSender(s FrameSender)

SetSender wires L2's frame-send hook.

func (*Manager) SetX25519Keys 

func (m *Manager) SetX25519Keys(priv *ecdh.PrivateKey, pub []byte)

SetX25519Keys installs our X25519 keypair (used for ECDH on inbound key-exchange frames and for the pubkey slot in outbound frames).

func (*Manager) Store 

func (m *Manager) Store() *Store

Store returns the per-peer Crypto registry owned by this Manager. L6 (envelope) imports it to wrap/unwrap AEAD frames; L7 (tunnel) imports it for membership probes (Has/IsReady) and bookkeeping (Install/Drop) on rekey paths.

type PeerAddrLookup 

type PeerAddrLookup func(peerNodeID uint32) *net.UDPAddr

PeerAddrLookup returns the currently-known UDP address for peerNodeID. Used by sendKeyExchangeToNode to find the destination. tunnel.go satisfies this with a closure reading tm.peers under tm.mu.

type PendingRekeyState 

type PendingRekeyState struct {
	FirstSentAt time.Time
	LastSentAt  time.Time
	Attempts    int
}

PendingRekeyState tracks a key-exchange we sent and are waiting on. Cleared when handleEncrypted records a successful decrypt from peer (proof their crypto matches ours). The retransmit loop bumps LastSentAt and Attempts on each retry; gives up after MaxRekeyAttempts to avoid hammering a peer that's just gone.

type PostInstallEvent 

type PostInstallEvent struct {
	PeerNodeID    uint32
	From          *net.UDPAddr
	FromRelay     bool
	Authenticated bool
	HadCrypto     bool // true if an entry existed before
	KeyChanged    bool // true if the peer's X25519 ephemeral key actually changed
	OldCrypto     *Crypto
	NewCrypto     *Crypto
	PeerEd25519   ed25519.PublicKey // non-nil for auth path
}

PostInstallEvent describes a freshly-installed Crypto.

type PostInstallHook 

type PostInstallHook func(ev PostInstallEvent)

PostInstallHook is invoked AFTER a successful HandleAuthFrame / HandleUnauthFrame installs (or refreshes) a Crypto. Carries enough context for the daemon to do peer-endpoint bookkeeping, salvage replay, flushPending, etc. Implemented in tunnel.go.

type SalvageEntry 

type SalvageEntry struct {
	Plaintext []byte
	When      time.Time
}

SalvageEntry is a single plaintext frame retained for post-rekey replay.

type Store 

type Store struct {

	// EncryptOK / EncryptFail track AEAD operation success/failure
	// counts. Exposed as atomic counters so L7 / metrics readers don't
	// need to take Store.mu. Bumped by the L6 framing functions in
	// pkg/daemon/envelope.
	EncryptOK   atomic.Uint64
	EncryptFail atomic.Uint64
	// contains filtered or unexported fields
}

Store is the per-tunnel key-state registry. It owns the map of node ID → Crypto. Counter, replay-window, and salvage state live on the per-peer Crypto values; Store's mutex only protects the map itself.

The mutex is intentionally a simple sync.RWMutex used as a leaf lock — it must NEVER be held while invoking a TunnelManager-side mutex (tm.mu, tm.rkPendingMu, tm.pendMu). All callers obey this by reading from Store first, then mutating tm state in a separate critical section.

Store is L5-owned. L6 (envelope) imports Store to pull per-peer Crypto pointers when wrapping/unwrapping AEAD frames; the import direction is L6 → L5, matching docs/architecture/01-LAYERS.md.

func NewStore 

func NewStore() *Store

NewStore returns an empty Store.

func (*Store) CompareAndDrop 

func (s *Store) CompareAndDrop(peerNodeID uint32, expected *Crypto) bool

CompareAndDrop deletes the entry only if the currently-installed pointer equals expected. Returns true if a delete occurred. Used by the decrypt-fail drop path to avoid deleting a Crypto that a concurrent rekey already replaced.

func (*Store) DrainSalvage 

func (s *Store) DrainSalvage(c *Crypto) []SalvageEntry

DrainSalvage atomically removes and returns all non-aged salvage entries from c. Returns nil if c is nil or empty. Each returned Plaintext is the same byte slice that was stored — RecordSalvage already copied at insert time.

func (*Store) Drop 

func (s *Store) Drop(peerNodeID uint32)

Drop removes the Crypto for peerNodeID. Safe even if no entry exists.

func (*Store) Get 

func (s *Store) Get(peerNodeID uint32) *Crypto

Get returns the Crypto installed for peerNodeID, or nil if none.

func (*Store) Has 

func (s *Store) Has(peerNodeID uint32) bool

Has returns true if a Crypto is installed for peerNodeID.

func (*Store) Install 

func (s *Store) Install(peerNodeID uint32, c *Crypto)

Install adds (or replaces) the Crypto for the given peer. Caller is responsible for any "preserve on duplicate same-pubkey" logic — Store just unconditionally writes.

func (*Store) IsReady 

func (s *Store) IsReady(peerNodeID uint32) bool

IsReady returns true if a Crypto is installed AND its handshake is complete (Ready=true).

func (*Store) Len 

func (s *Store) Len() int

Len returns the number of installed Cryptos. Used by the MaxCryptoPeers cap pre-check.

func (*Store) LocalNodeID 

func (s *Store) LocalNodeID() uint32

LocalNodeID returns our own node ID.

func (*Store) PeerIDs 

func (s *Store) PeerIDs() []uint32

PeerIDs returns a snapshot of all peer IDs with installed Cryptos.

func (*Store) RecordSalvage 

func (s *Store) RecordSalvage(c *Crypto, plaintext []byte)

RecordSalvage stashes a plaintext send into the per-peer ring buffer. On a subsequent peer-initiated rekey, DrainSalvage will hand back the entries; the caller re-encrypts with the new key and re-sends — recovering data that the peer dropped because our frame was keyed under their now-stale crypto context.

Bounded by SalvageMaxEntries and SalvageMaxAge. The plaintext is copied, not referenced — caller can reuse its buffer.

nil c is a no-op (safe for callers that don't gate on Ready).

func (*Store) SetLocalNodeID 

func (s *Store) SetLocalNodeID(id uint32)

SetLocalNodeID stores our own node ID (used in encrypt-side AAD and secure-frame headers). Safe to call concurrently with other Store operations.

func (*Store) ShouldDropOnDecryptFail 

func (s *Store) ShouldDropOnDecryptFail(peerNodeID uint32, c *Crypto) bool

ShouldDropOnDecryptFail implements the rc5 grace gate: returns true if the failing Crypto's DecryptFailCount has reached DecryptFailDropThreshold AND the Crypto is older than DecryptFailDropGrace AND it is still the currently-installed entry for peerNodeID.

The caller (L6 framing path) is responsible for the side-effect: drop via CompareAndDrop and trigger a fresh key exchange. This split keeps the rekey-trigger / event-publish responsibility OUT of Store.

type VerifyFunc 

type VerifyFunc func(nodeID uint32) (ed25519.PublicKey, error)

VerifyFunc fetches the canonical Ed25519 public key for nodeID (typically from the registry).

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