libp2p

type DHTOptions struct {
	// BootstrapPeers seeds the DHT routing table. Reuse the libp2p
	// host's bootstrap list for simplicity.
	BootstrapPeers []string
	// NetworkName is the Filecoin network identifier used to construct
	// the DHT protocol ID. Defaults to build.MainnetNetworkName.
	//
	// Why this matters: Filecoin's DHT protocol is
	// /fil/kad/<network>/kad/1.0.0 (e.g. /fil/kad/testnetnet/kad/1.0.0
	// on mainnet). A bare /fil/kad/1.0.0 client cannot peer with any
	// real Filecoin node — the protocol negotiation fails and the peer
	// gets evicted from the routing table. We pass
	// build.MainnetNetworkName here to match what Lotus and Forest
	// advertise.
	NetworkName string
	// RefreshInterval controls how often the background loop refreshes
	// the DHT routing table + reconnects to bootstrap peers if peer
	// count fell. Default 5 minutes.
	RefreshInterval time.Duration
	// TargetPeers is the floor below which the refresh loop tries
	// harder (re-bootstraps + dials more aggressively). Default 30.
	TargetPeers int

	// ClosestWalkInterval drives the fast loop that runs
	// dht.GetClosestPeers(self) to populate the routing table from
	// across the swarm. Default 5 minutes.
	ClosestWalkInterval time.Duration
	// DialWalkInterval drives the slower loop that walks the DHT
	// routing table and opportunistically dials peers we don't already
	// have a connection to, capped by the host's connmgr high-water.
	// Default 10 minutes.
	DialWalkInterval time.Duration
	// MaxDialsPerCycle caps the number of outbound dials a single
	// dial-walk cycle initiates. Default 25 — enough to grow the peer
	// set without thundering, and well below the connmgr trim trigger.
	MaxDialsPerCycle int
	// PerDialTimeout caps each outbound dial. Default 8 seconds.
	PerDialTimeout time.Duration
}

type Host struct {
	H      host.Host
	PubSub *pubsub.PubSub

	// Phase 10: BandwidthCounter is the libp2p-standard metrics reporter
	// installed via libp2p.BandwidthReporter on construction. RPC's
	// NetBandwidthStats reads from this counter directly. Nil only when
	// HostConfig.DisableBandwidthCounter is set (used by tests).
	BW *metrics.BandwidthCounter
	// contains filtered or unexported fields
}

type HostConfig struct {
	// Listen multiaddrs. Default: ["/ip4/0.0.0.0/tcp/0", "/ip4/0.0.0.0/udp/0/quic-v1"].
	ListenAddrs []string
	// BootstrapPeers is the list of multiaddrs to dial on startup.
	BootstrapPeers []string
	// MaxPeers is the connection-manager *high-water-mark*: when peer
	// count exceeds this, connmgr starts trimming the lowest-tagged
	// connections after the grace period. Default 200 (V1.2.1 lift;
	// previously 50 hard cap).
	MaxPeers int
	// MinPeers is the connection-manager *low-water-mark*: connmgr keeps
	// at least this many peers around even under trim pressure, and the
	// DHT discovery loop targets this number when dialing fresh peers.
	// Default 50.
	MinPeers int
	// ConnMgrGrace is how long a new connection is protected from trim.
	// Default 20 seconds.
	ConnMgrGrace time.Duration
	// UserAgent overrides the libp2p User-Agent. Default is derived from
	// internal/buildinfo so the wire identifier tracks the release tag.
	UserAgent string
	// DisableBandwidthCounter skips the metrics.BandwidthCounter wiring.
	// Used by tests that don't want to allocate the counter.
	DisableBandwidthCounter bool
	// GossipSubDirectPeers is a list of libp2p multiaddrs that the
	// gossipsub router should treat as direct mesh neighbours for the
	// block / message topics. We use it to pin big fast Filecoin nodes
	// (ChainSafe, chain.love, filincubator, devtty) into our mesh so
	// new heads propagate at the same speed they do for those nodes.
	// Defaults to BootstrapPeers when empty.
	GossipSubDirectPeers []string
	// PubSubTracer, when set, is registered as gossipsub's RawTracer at
	// construction. Used by the head-corroboration tracker (#80 part 2)
	// so duplicate block deliveries are counted per source peer.
	PubSubTracer pubsub.RawTracer
}

type KeepaliveStats struct {
	Cycles        uint64 // total keepalive ticks
	Triggered     uint64 // cycles where we were below MinPeers and acted
	BootstrapDial uint64 // cumulative bootstrap-peer dials
	RoutingDial   uint64 // cumulative routing-table-walk dials
	// Stuck: cumulative count of peers we dialed on the previous tick
	// that were NOT still connected when the next tick fired. High Stuck
	// values relative to RoutingDial indicate peers are accepting the
	// libp2p stream then closing the connection. That's the failure mode
	// the issue #9 follow-up was diagnosed against.
	Stuck uint64
	// ClosestWalks fired by the keepalive (aggressive, only when peer
	// count is below MinPeers/2). Separate from the periodic 5-minute
	// dhtClosestWalkLoop.
	ClosestWalks  uint64
	LastPeerCount int // peer count observed at the last tick
}