core-lightning/gossipd/gossipd.c

/*~ Welcome to the gossip daemon: keeper of maps!
 *
 * This is the last "global" daemon; it has three purposes.
 *
 * 1. To determine routes for payments when lightningd asks.
 * 2. The second purpose is to receive gossip from peers (via their
 *    per-peer daemons) and send it out to them.
 * 3. Talk to `connectd` to to answer address queries for nodes.
 *
 * The gossip protocol itself is fairly simple, but has some twists which
 * add complexity to this daemon.
 */
#include "config.h"
#include <ccan/cast/cast.h>
#include <ccan/tal/str/str.h>
#include <common/blindedpath.h>
#include <common/blinding.h>
#include <common/daemon_conn.h>
#include <common/ecdh_hsmd.h>
#include <common/lease_rates.h>
#include <common/memleak.h>
#include <common/pseudorand.h>
#include <common/sphinx.h>
#include <common/status.h>
#include <common/subdaemon.h>
#include <common/timeout.h>
#include <common/type_to_string.h>
#include <common/wire_error.h>
#include <connectd/connectd_gossipd_wiregen.h>
#include <errno.h>
#include <gossipd/gossip_generation.h>
#include <gossipd/gossip_store_wiregen.h>
#include <gossipd/gossipd.h>
#include <gossipd/gossipd_peerd_wiregen.h>
#include <gossipd/gossipd_wiregen.h>
#include <gossipd/queries.h>
#include <gossipd/routing.h>
#include <gossipd/seeker.h>
#include <sodium/crypto_aead_chacha20poly1305.h>

/*~ A channel consists of a `struct half_chan` for each direction, each of
 * which has a `flags` word from the `channel_update`; bit 1 is
 * ROUTING_FLAGS_DISABLED in the `channel_update`.  But we also keep a local
 * whole-channel flag which indicates it's not available; we use this when a
 * peer disconnects, and generate a `channel_update` to tell the world lazily
 * when someone asks. */
static void peer_disable_channels(struct daemon *daemon, const struct node *node)
{
	/* If this peer had a channel with us, mark it disabled. */
	struct chan_map_iter i;
	const struct chan *c;

	for (c = first_chan(node, &i); c; c = next_chan(node, &i)) {
		int direction;
		if (!local_direction(daemon->rstate, c, &direction))
			continue;
		local_disable_chan(daemon, c, direction);
	}
}

/*~ This cancels the soft-disables when the peer reconnects. */
static void peer_enable_channels(struct daemon *daemon, const struct node *node)
{
	/* If this peer had a channel with us, mark it disabled. */
	struct chan_map_iter i;
	const struct chan *c;

	for (c = first_chan(node, &i); c; c = next_chan(node, &i)) {
		int direction;
		if (!local_direction(daemon->rstate, c, &direction))
			continue;
		local_enable_chan(daemon, c, direction);
	}
}

/*~ Destroy a peer, usually because the per-peer daemon has exited.
 *
 * Were you wondering why we call this "destroy_peer" and not "peer_destroy"?
 * I thought not!  But while CCAN modules are required to keep to their own
 * prefix namespace, leading to unnatural word order, we couldn't stomach that
 * for our own internal use.  We use 'find_foo', 'destroy_foo' and 'new_foo'.
 */
static void destroy_peer(struct peer *peer)
{
	struct node *node;

	/* Remove it from the peers list */
	list_del_from(&peer->daemon->peers, &peer->list);

	/* If we have a channel with this peer, disable it. */
	node = get_node(peer->daemon->rstate, &peer->id);
	if (node)
		peer_disable_channels(peer->daemon, node);

	/* This is tricky: our lifetime is tied to the daemon_conn; it's our
	 * parent, so we are freed if it is, but we need to free it if we're
	 * freed manually.  tal_free() treats this as a noop if it's already
	 * being freed */
	tal_free(peer->dc);
}

/* Search for a peer. */
struct peer *find_peer(struct daemon *daemon, const struct node_id *id)
{
	struct peer *peer;

	list_for_each(&daemon->peers, peer, list)
		if (node_id_eq(&peer->id, id))
			return peer;
	return NULL;
}

/* Increase a peer's gossip_counter, if peer not NULL */
void peer_supplied_good_gossip(struct peer *peer, size_t amount)
{
	if (peer)
		peer->gossip_counter += amount;
}

/* Queue a gossip message for the peer: the subdaemon on the other end simply
 * forwards it to the peer. */
void queue_peer_msg(struct peer *peer, const u8 *msg TAKES)
{
	daemon_conn_send(peer->dc, msg);
}

/*~ We have a helper for messages from the store. */
void queue_peer_from_store(struct peer *peer,
			   const struct broadcastable *bcast)
{
	struct gossip_store *gs = peer->daemon->rstate->gs;
	queue_peer_msg(peer, take(gossip_store_get(NULL, gs, bcast->index)));
}

/*~ We don't actually keep node_announcements in memory; we keep them in
 * a file called `gossip_store`.  If we need some node details, we reload
 * and reparse.  It's slow, but generally rare. */
static bool get_node_announcement(const tal_t *ctx,
				  struct daemon *daemon,
				  const struct node *n,
				  u8 rgb_color[3],
				  u8 alias[32],
				  u8 **features,
				  struct wireaddr **wireaddrs,
				  struct lease_rates **rates)
{
	const u8 *msg;
	struct node_id id;
	secp256k1_ecdsa_signature signature;
	u32 timestamp;
	u8 *addresses;
	struct tlv_node_ann_tlvs *na_tlvs;

	if (!n->bcast.index)
		return false;

	msg = gossip_store_get(tmpctx, daemon->rstate->gs, n->bcast.index);

	/* Note: validity of node_id is already checked. */
	na_tlvs = tlv_node_ann_tlvs_new(ctx);
	if (!fromwire_node_announcement(ctx, msg,
					&signature, features,
					&timestamp,
					&id, rgb_color, alias,
					&addresses,
					na_tlvs)) {
		status_broken("Bad local node_announcement @%u: %s",
			      n->bcast.index, tal_hex(tmpctx, msg));
		return false;
	}

	if (!node_id_eq(&id, &n->id) || timestamp != n->bcast.timestamp) {
		status_broken("Wrong node_announcement @%u:"
			      " expected %s timestamp %u "
			      " got %s timestamp %u",
			      n->bcast.index,
			      type_to_string(tmpctx, struct node_id, &n->id),
			      timestamp,
			      type_to_string(tmpctx, struct node_id, &id),
			      n->bcast.timestamp);
		return false;
	}

	*wireaddrs = fromwire_wireaddr_array(ctx, addresses);
	*rates = tal_steal(ctx, na_tlvs->option_will_fund);

	tal_free(addresses);
	return true;
}

/* Version which also does nodeid lookup */
static bool get_node_announcement_by_id(const tal_t *ctx,
					struct daemon *daemon,
					const struct node_id *node_id,
					u8 rgb_color[3],
					u8 alias[32],
					u8 **features,
					struct wireaddr **wireaddrs,
					struct lease_rates **rates)
{
	struct node *n = get_node(daemon->rstate, node_id);
	if (!n)
		return false;

	return get_node_announcement(ctx, daemon, n, rgb_color, alias,
				     features, wireaddrs, rates);
}

/*~Routines to handle gossip messages from peer, forwarded by subdaemons.
 *-----------------------------------------------------------------------
 *
 * It's not the subdaemon's fault if they're malformed or invalid; so these
 * all return an error packet which gets sent back to the subdaemon in that
 * case.
 */

/* The routing code checks that it's basically valid, returning an
 * error message for the peer or NULL.  NULL means it's OK, but the
 * message might be redundant, in which case scid is also NULL.
 * Otherwise `scid` gives us the short_channel_id claimed by the
 * message, and puts the announcemnt on an internal 'pending'
 * queue.  We'll send a request to lightningd to look it up, and continue
 * processing in `handle_txout_reply`. */
static const u8 *handle_channel_announcement_msg(struct daemon *daemon,
						 struct peer *peer,
						 const u8 *msg)
{
	const struct short_channel_id *scid;
	const u8 *err;

	/* If it's OK, tells us the short_channel_id to lookup; it notes
	 * if this is the unknown channel the peer was looking for (in
	 * which case, it frees and NULLs that ptr) */
	err = handle_channel_announcement(daemon->rstate, msg,
					  daemon->current_blockheight,
					  &scid, peer);
	if (err)
		return err;
	else if (scid) {
		/* We give them some grace period, in case we don't know about
		 * block yet. */
		if (daemon->current_blockheight == 0
		    || !is_scid_depth_announceable(scid,
						   daemon->current_blockheight)) {
			tal_arr_expand(&daemon->deferred_txouts, *scid);
		} else {
			daemon_conn_send(daemon->master,
					 take(towire_gossipd_get_txout(NULL,
								      scid)));
		}
	}
	return NULL;
}

static u8 *handle_channel_update_msg(struct peer *peer, const u8 *msg)
{
	struct short_channel_id unknown_scid;
	/* Hand the channel_update to the routing code */
	u8 *err;

	unknown_scid.u64 = 0;
	err = handle_channel_update(peer->daemon->rstate, msg, peer,
				    &unknown_scid, false);
	if (err)
		return err;

	/* If it's an unknown channel, ask someone about it */
	if (unknown_scid.u64 != 0)
		query_unknown_channel(peer->daemon, peer, &unknown_scid);

	/*~ As a nasty compromise in the spec, we only forward `channel_announce`
	 * once we have a `channel_update`; the channel isn't *usable* for
	 * routing until you have both anyway.  For this reason, we might have
	 * just sent out our own channel_announce, so we check if it's time to
	 * send a node_announcement too. */
	maybe_send_own_node_announce(peer->daemon, false);
	return NULL;
}

static u8 *handle_node_announce(struct peer *peer, const u8 *msg)
{
	bool was_unknown = false;
	u8 *err;

	err = handle_node_announcement(peer->daemon->rstate, msg, peer,
				       &was_unknown);
	if (was_unknown)
		query_unknown_node(peer->daemon->seeker, peer);
	return err;
}

static bool handle_local_channel_announcement(struct daemon *daemon,
					      struct peer *peer,
					      const u8 *msg)
{
	u8 *cannouncement;
	const u8 *err;

	if (!fromwire_gossipd_local_channel_announcement(msg, msg,
							 &cannouncement)) {
		status_broken("peer %s bad local_channel_announcement %s",
			      type_to_string(tmpctx, struct node_id, &peer->id),
			      tal_hex(tmpctx, msg));
		return false;
	}

	err = handle_channel_announcement_msg(daemon, peer, cannouncement);
	if (err) {
		status_broken("peer %s invalid local_channel_announcement %s (%s)",
			      type_to_string(tmpctx, struct node_id, &peer->id),
			      tal_hex(tmpctx, msg),
			      tal_hex(tmpctx, err));
		return false;
	}

	return true;
}

/* Peer sends obsolete onion msg. */
static u8 *handle_obs2_onion_message(struct peer *peer, const u8 *msg)
{
	enum onion_wire badreason;
	struct onionpacket *op;
	struct pubkey blinding, ephemeral;
	struct route_step *rs;
	u8 *onion;
	struct tlv_obs2_onionmsg_payload *om;
	struct secret ss, onion_ss;
	const u8 *cursor;
	size_t max, maxlen;

	/* Ignore unless explicitly turned on. */
	if (!feature_offered(peer->daemon->our_features->bits[NODE_ANNOUNCE_FEATURE],
			     OPT_ONION_MESSAGES))
		return NULL;

	/* FIXME: ratelimit! */
	if (!fromwire_obs2_onion_message(msg, msg, &blinding, &onion))
		return towire_warningfmt(peer, NULL, "Bad onion_message");

	/* We unwrap the onion now. */
	op = parse_onionpacket(tmpctx, onion, tal_bytelen(onion), &badreason);
	if (!op) {
		status_peer_debug(&peer->id, "onion msg: can't parse onionpacket: %s",
				  onion_wire_name(badreason));
		return NULL;
	}

	ephemeral = op->ephemeralkey;
	if (!unblind_onion(&blinding, ecdh, &ephemeral, &ss)) {
		status_peer_debug(&peer->id, "onion msg: can't unblind onionpacket");
		return NULL;
	}

	/* Now get onion shared secret and parse it. */
	ecdh(&ephemeral, &onion_ss);
	rs = process_onionpacket(tmpctx, op, &onion_ss, NULL, 0, false);
	if (!rs) {
		status_peer_debug(&peer->id,
				  "onion msg: can't process onionpacket ss=%s",
				  type_to_string(tmpctx, struct secret, &onion_ss));
		return NULL;
	}

	/* The raw payload is prepended with length in the modern onion. */
	cursor = rs->raw_payload;
	max = tal_bytelen(rs->raw_payload);
	maxlen = fromwire_bigsize(&cursor, &max);
	if (!cursor) {
		status_peer_debug(&peer->id, "onion msg: Invalid hop payload %s",
				  tal_hex(tmpctx, rs->raw_payload));
		return NULL;
	}
	if (maxlen > max) {
		status_peer_debug(&peer->id, "onion msg: overlong hop payload %s",
				  tal_hex(tmpctx, rs->raw_payload));
		return NULL;
	}

	om = tlv_obs2_onionmsg_payload_new(msg);
	if (!fromwire_obs2_onionmsg_payload(&cursor, &maxlen, om)) {
		status_peer_debug(&peer->id, "onion msg: invalid onionmsg_payload %s",
				  tal_hex(tmpctx, rs->raw_payload));
		return NULL;
	}

	if (rs->nextcase == ONION_END) {
		struct pubkey *reply_blinding, *first_node_id, me, alias;
		const struct onionmsg_path **reply_path;
		struct secret *self_id;
		u8 *omsg;

		if (!pubkey_from_node_id(&me, &peer->daemon->id)) {
			status_broken("Failed to convert own id");
			return NULL;
		}

		/* Final enctlv is actually optional */
		if (!om->enctlv) {
			alias = me;
			self_id = NULL;
		} else if (!decrypt_obs2_final_enctlv(tmpctx, &blinding, &ss,
						      om->enctlv, &me, &alias,
						      &self_id)) {
			status_peer_debug(&peer->id,
					  "onion msg: failed to decrypt enctlv"
					  " %s", tal_hex(tmpctx, om->enctlv));
			return NULL;
		}

		if (om->reply_path) {
			first_node_id = &om->reply_path->first_node_id;
			reply_blinding = &om->reply_path->blinding;
			reply_path = cast_const2(const struct onionmsg_path **,
						 om->reply_path->path);
		} else {
			first_node_id = NULL;
			reply_blinding = NULL;
			reply_path = NULL;
		}

		/* We re-marshall here by policy, before handing to lightningd */
		omsg = tal_arr(tmpctx, u8, 0);
		towire_tlvstream_raw(&omsg, om->fields);
		daemon_conn_send(peer->daemon->master,
				 take(towire_gossipd_got_onionmsg_to_us(NULL,
							true, /* obs2 */
							&alias, self_id,
							reply_blinding,
							first_node_id,
							reply_path,
							omsg)));
	} else {
		struct pubkey next_node, next_blinding;
		struct peer *next_peer;
		struct node_id next_node_id;

		/* This fails as expected if no enctlv. */
		if (!decrypt_obs2_enctlv(&blinding, &ss, om->enctlv, &next_node,
					 &next_blinding)) {
			status_peer_debug(&peer->id,
					  "onion msg: invalid enctlv %s",
					  tal_hex(tmpctx, om->enctlv));
			return NULL;
		}

		/* Even though lightningd checks for valid ids, there's a race
		 * where it might vanish before we read this command. */
		node_id_from_pubkey(&next_node_id, &next_node);
		next_peer = find_peer(peer->daemon, &next_node_id);
		if (!next_peer) {
			status_peer_debug(&peer->id,
					  "onion msg: unknown next peer %s",
					  type_to_string(tmpctx,
							 struct pubkey,
							 &next_node));
			return NULL;
		}
		queue_peer_msg(next_peer,
			       take(towire_obs2_onion_message(NULL,
							      &next_blinding,
							      serialize_onionpacket(tmpctx, rs->next))));
	}

	return NULL;
}

static void onionmsg_req(struct daemon *daemon, const u8 *msg)
{
	struct node_id id;
	u8 *onionmsg;
	struct pubkey blinding;
	struct peer *peer;
	bool obs2;

	if (!fromwire_gossipd_send_onionmsg(msg, msg, &obs2, &id, &onionmsg, &blinding))
		master_badmsg(WIRE_GOSSIPD_SEND_ONIONMSG, msg);

	/* Even though lightningd checks for valid ids, there's a race
	 * where it might vanish before we read this command. */
	peer = find_peer(daemon, &id);
	if (peer) {
		u8 *omsg;
		if (obs2)
			omsg = towire_obs2_onion_message(NULL, &blinding, onionmsg);
		else
			omsg = towire_onion_message(NULL, &blinding, onionmsg);
		queue_peer_msg(peer, take(omsg));
	}
}

/* Peer sends an onion msg. */
static u8 *handle_onion_message(struct peer *peer, const u8 *msg)
{
	enum onion_wire badreason;
	struct onionpacket *op;
	struct pubkey blinding, ephemeral;
	struct route_step *rs;
	u8 *onion;
	struct tlv_onionmsg_payload *om;
	struct secret ss, onion_ss;
	const u8 *cursor;
	size_t max, maxlen;

	/* Ignore unless explicitly turned on. */
	if (!feature_offered(peer->daemon->our_features->bits[NODE_ANNOUNCE_FEATURE],
			     OPT_ONION_MESSAGES))
		return NULL;

	/* FIXME: ratelimit! */
	if (!fromwire_onion_message(msg, msg, &blinding, &onion))
		return towire_warningfmt(peer, NULL, "Bad onion_message");

	/* We unwrap the onion now. */
	op = parse_onionpacket(tmpctx, onion, tal_bytelen(onion), &badreason);
	if (!op) {
		status_peer_debug(&peer->id, "onion msg: can't parse onionpacket: %s",
				  onion_wire_name(badreason));
		return NULL;
	}

	ephemeral = op->ephemeralkey;
	if (!unblind_onion(&blinding, ecdh, &ephemeral, &ss)) {
		status_peer_debug(&peer->id, "onion msg: can't unblind onionpacket");
		return NULL;
	}

	/* Now get onion shared secret and parse it. */
	ecdh(&ephemeral, &onion_ss);
	rs = process_onionpacket(tmpctx, op, &onion_ss, NULL, 0, false);
	if (!rs) {
		status_peer_debug(&peer->id,
				  "onion msg: can't process onionpacket ss=%s",
				  type_to_string(tmpctx, struct secret, &onion_ss));
		return NULL;
	}

	/* The raw payload is prepended with length in the modern onion. */
	cursor = rs->raw_payload;
	max = tal_bytelen(rs->raw_payload);
	maxlen = fromwire_bigsize(&cursor, &max);
	if (!cursor) {
		status_peer_debug(&peer->id, "onion msg: Invalid hop payload %s",
				  tal_hex(tmpctx, rs->raw_payload));
		return NULL;
	}
	if (maxlen > max) {
		status_peer_debug(&peer->id, "onion msg: overlong hop payload %s",
				  tal_hex(tmpctx, rs->raw_payload));
		return NULL;
	}

	om = tlv_onionmsg_payload_new(msg);
	if (!fromwire_onionmsg_payload(&cursor, &maxlen, om)) {
		status_peer_debug(&peer->id, "onion msg: invalid onionmsg_payload %s",
				  tal_hex(tmpctx, rs->raw_payload));
		return NULL;
	}

	if (rs->nextcase == ONION_END) {
		struct pubkey *reply_blinding, *first_node_id, me, alias;
		const struct onionmsg_path **reply_path;
		struct secret *self_id;
		u8 *omsg;

		if (!pubkey_from_node_id(&me, &peer->daemon->id)) {
			status_broken("Failed to convert own id");
			return NULL;
		}

		/* Final enctlv is actually optional */
		if (!om->encrypted_data_tlv) {
			alias = me;
			self_id = NULL;
		} else if (!decrypt_final_enctlv(tmpctx, &blinding, &ss,
						 om->encrypted_data_tlv, &me, &alias,
						 &self_id)) {
			status_peer_debug(&peer->id,
					  "onion msg: failed to decrypt enctlv"
					  " %s", tal_hex(tmpctx, om->encrypted_data_tlv));
			return NULL;
		}

		if (om->reply_path) {
			first_node_id = &om->reply_path->first_node_id;
			reply_blinding = &om->reply_path->blinding;
			reply_path = cast_const2(const struct onionmsg_path **,
						 om->reply_path->path);
		} else {
			first_node_id = NULL;
			reply_blinding = NULL;
			reply_path = NULL;
		}

		/* We re-marshall here by policy, before handing to lightningd */
		omsg = tal_arr(tmpctx, u8, 0);
		towire_tlvstream_raw(&omsg, om->fields);
		daemon_conn_send(peer->daemon->master,
				 take(towire_gossipd_got_onionmsg_to_us(NULL,
							false, /* !obs2 */
							&alias, self_id,
							reply_blinding,
							first_node_id,
							reply_path,
							omsg)));
	} else {
		struct pubkey next_node, next_blinding;
		struct peer *next_peer;
		struct node_id next_node_id;

		/* This fails as expected if no enctlv. */
		if (!decrypt_enctlv(&blinding, &ss, om->encrypted_data_tlv, &next_node,
					 &next_blinding)) {
			status_peer_debug(&peer->id,
					  "onion msg: invalid enctlv %s",
					  tal_hex(tmpctx, om->encrypted_data_tlv));
			return NULL;
		}

		/* FIXME: Handle short_channel_id! */
		node_id_from_pubkey(&next_node_id, &next_node);
		next_peer = find_peer(peer->daemon, &next_node_id);
		if (!next_peer) {
			status_peer_debug(&peer->id,
					  "onion msg: unknown next peer %s",
					  type_to_string(tmpctx,
							 struct pubkey,
							 &next_node));
			return NULL;
		}
		queue_peer_msg(next_peer,
			       take(towire_onion_message(NULL,
							 &next_blinding,
							 serialize_onionpacket(tmpctx, rs->next))));
	}

	return NULL;
}

/*~ This is where the per-peer daemons send us messages.  It's either forwarded
 * gossip, or a request for information.  We deliberately use non-overlapping
 * message types so we can distinguish them. */
static struct io_plan *peer_msg_in(struct io_conn *conn,
				    const u8 *msg,
				    struct peer *peer)
{
	const u8 *err;
	bool ok;

	/* These are messages relayed from peer */
	switch ((enum peer_wire)fromwire_peektype(msg)) {
	case WIRE_CHANNEL_ANNOUNCEMENT:
		err = handle_channel_announcement_msg(peer->daemon, peer, msg);
		goto handled_relay;
	case WIRE_CHANNEL_UPDATE:
		err = handle_channel_update_msg(peer, msg);
		goto handled_relay;
	case WIRE_NODE_ANNOUNCEMENT:
		err = handle_node_announce(peer, msg);
		goto handled_relay;
	case WIRE_QUERY_CHANNEL_RANGE:
		err = handle_query_channel_range(peer, msg);
		goto handled_relay;
	case WIRE_REPLY_CHANNEL_RANGE:
		err = handle_reply_channel_range(peer, msg);
		goto handled_relay;
	case WIRE_QUERY_SHORT_CHANNEL_IDS:
		err = handle_query_short_channel_ids(peer, msg);
		goto handled_relay;
	case WIRE_REPLY_SHORT_CHANNEL_IDS_END:
		err = handle_reply_short_channel_ids_end(peer, msg);
		goto handled_relay;
	case WIRE_OBS2_ONION_MESSAGE:
		err = handle_obs2_onion_message(peer, msg);
		goto handled_relay;
	case WIRE_ONION_MESSAGE:
		err = handle_onion_message(peer, msg);
		goto handled_relay;

	/* These are non-gossip messages (!is_msg_for_gossipd()) */
	case WIRE_WARNING:
	case WIRE_INIT:
	case WIRE_ERROR:
	case WIRE_PING:
	case WIRE_PONG:
	case WIRE_OPEN_CHANNEL:
	case WIRE_ACCEPT_CHANNEL:
	case WIRE_FUNDING_CREATED:
	case WIRE_FUNDING_SIGNED:
	case WIRE_FUNDING_LOCKED:
	case WIRE_SHUTDOWN:
	case WIRE_CLOSING_SIGNED:
	case WIRE_UPDATE_ADD_HTLC:
	case WIRE_UPDATE_FULFILL_HTLC:
	case WIRE_UPDATE_FAIL_HTLC:
	case WIRE_UPDATE_FAIL_MALFORMED_HTLC:
	case WIRE_COMMITMENT_SIGNED:
	case WIRE_REVOKE_AND_ACK:
	case WIRE_UPDATE_FEE:
	case WIRE_UPDATE_BLOCKHEIGHT:
	case WIRE_CHANNEL_REESTABLISH:
	case WIRE_ANNOUNCEMENT_SIGNATURES:
	case WIRE_GOSSIP_TIMESTAMP_FILTER:
	case WIRE_TX_ADD_INPUT:
	case WIRE_TX_REMOVE_INPUT:
	case WIRE_TX_ADD_OUTPUT:
	case WIRE_TX_REMOVE_OUTPUT:
	case WIRE_TX_COMPLETE:
	case WIRE_TX_SIGNATURES:
	case WIRE_OPEN_CHANNEL2:
	case WIRE_ACCEPT_CHANNEL2:
	case WIRE_INIT_RBF:
	case WIRE_ACK_RBF:
#if EXPERIMENTAL_FEATURES
	case WIRE_STFU:
#endif
		status_broken("peer %s: relayed unexpected msg of type %s",
			      type_to_string(tmpctx, struct node_id, &peer->id),
			      peer_wire_name(fromwire_peektype(msg)));
		return io_close(conn);
	}

	/* Must be a gossipd_peerd_wire_type asking us to do something. */
	switch ((enum gossipd_peerd_wire)fromwire_peektype(msg)) {
	case WIRE_GOSSIPD_LOCAL_CHANNEL_UPDATE:
		ok = handle_local_channel_update(peer->daemon, &peer->id, msg);
		goto handled_cmd;
	case WIRE_GOSSIPD_LOCAL_CHANNEL_ANNOUNCEMENT:
		ok = handle_local_channel_announcement(peer->daemon, peer, msg);
		goto handled_cmd;
	}

	if (fromwire_peektype(msg) == WIRE_GOSSIP_STORE_PRIVATE_CHANNEL) {
		ok = routing_add_private_channel(peer->daemon->rstate, peer,
						 msg, 0);
		goto handled_cmd;
	}

	/* Anything else should not have been sent to us: close on it */
	status_peer_broken(&peer->id, "unexpected cmd of type %i %s",
			   fromwire_peektype(msg),
			   gossipd_peerd_wire_name(fromwire_peektype(msg)));
	return io_close(conn);

	/* Commands should always be OK. */
handled_cmd:
	if (!ok)
		return io_close(conn);
	goto done;

	/* Forwarded messages may be bad, so we have error which the per-peer
	 * daemon will forward to the peer. */
handled_relay:
	if (err)
		queue_peer_msg(peer, take(err));
done:
	return daemon_conn_read_next(conn, peer->dc);
}

/*~ This is where connectd tells us about a new peer, and we hand back an fd for
 * it to send us messages via peer_msg_in above */
static struct io_plan *connectd_new_peer(struct io_conn *conn,
					 struct daemon *daemon,
					 const u8 *msg)
{
	struct peer *peer = tal(conn, struct peer);
	struct node *node;
	int fds[2];

	if (!fromwire_gossipd_new_peer(msg, &peer->id,
				      &peer->gossip_queries_feature)) {
		status_broken("Bad new_peer msg from connectd: %s",
			      tal_hex(tmpctx, msg));
		return io_close(conn);
	}

	/* This can happen: we handle it gracefully, returning a `failed` msg. */
	if (socketpair(AF_LOCAL, SOCK_STREAM, 0, fds) != 0) {
		status_broken("Failed to create socketpair: %s",
			      strerror(errno));
		daemon_conn_send(daemon->connectd,
				 take(towire_gossipd_new_peer_reply(NULL,
								    false)));
		goto done;
	}

	/* We might not have noticed old peer is dead; kill it now. */
	tal_free(find_peer(daemon, &peer->id));

	/* Populate the rest of the peer info. */
	peer->daemon = daemon;
	peer->gossip_counter = 0;
	peer->scid_queries = NULL;
	peer->scid_query_idx = 0;
	peer->scid_query_nodes = NULL;
	peer->scid_query_nodes_idx = 0;
	peer->scid_query_outstanding = false;
	peer->range_replies = NULL;
	peer->query_channel_range_cb = NULL;

	/* We keep a list so we can find peer by id */
	list_add_tail(&peer->daemon->peers, &peer->list);
	tal_add_destructor(peer, destroy_peer);

	/* This is the new connection: calls maybe_send_query_responses when
	 * nothing else to send. */
	peer->dc = daemon_conn_new(daemon, fds[0],
				   peer_msg_in,
				   maybe_send_query_responses, peer);
	/* Free peer if conn closed (destroy_peer closes conn if peer freed) */
	tal_steal(peer->dc, peer);

	node = get_node(daemon->rstate, &peer->id);
	if (node)
		peer_enable_channels(daemon, node);

	/* This sends the initial timestamp filter. */
	seeker_setup_peer_gossip(daemon->seeker, peer);

	/* Reply with success, and the new fd and gossip_state. */
	daemon_conn_send(daemon->connectd,
			 take(towire_gossipd_new_peer_reply(NULL, true)));
	daemon_conn_send_fd(daemon->connectd, fds[1]);

done:
	return daemon_conn_read_next(conn, daemon->connectd);
}

/*~ lightningd asks us if we know any addresses for a given id. */
static struct io_plan *handle_get_address(struct io_conn *conn,
					  struct daemon *daemon,
					  const u8 *msg)
{
	struct node_id id;
	u8 rgb_color[3];
	u8 alias[32];
	u8 *features;
	struct wireaddr *addrs;
	struct lease_rates *rates;

	if (!fromwire_gossipd_get_addrs(msg, &id))
		master_badmsg(WIRE_GOSSIPD_GET_ADDRS, msg);

	if (!get_node_announcement_by_id(tmpctx, daemon, &id,
					 rgb_color, alias, &features, &addrs,
					 &rates))
		addrs = NULL;

	daemon_conn_send(daemon->master,
			 take(towire_gossipd_get_addrs_reply(NULL, addrs)));
	return daemon_conn_read_next(conn, daemon->master);
}

/*~ connectd's input handler is very simple. */
static struct io_plan *connectd_req(struct io_conn *conn,
				    const u8 *msg,
				    struct daemon *daemon)
{
	enum connectd_gossipd_wire t = fromwire_peektype(msg);

	switch (t) {
	case WIRE_GOSSIPD_NEW_PEER:
		return connectd_new_peer(conn, daemon, msg);

	/* We send these, don't receive them. */
	case WIRE_GOSSIPD_NEW_PEER_REPLY:
		break;
	}

	status_broken("Bad msg from connectd: %s",
		      tal_hex(tmpctx, msg));
	return io_close(conn);
}

/* BOLT #7:
 *
 * A node:
 *  - if a channel's oldest `channel_update`s `timestamp` is older than two weeks
 *    (1209600 seconds):
 *     - MAY prune the channel.
 *     - MAY ignore the channel.
 */
static void gossip_refresh_network(struct daemon *daemon)
{
	u64 now = gossip_time_now(daemon->rstate).ts.tv_sec;
	s64 highwater;
	struct node *n;

	/* Send out 1 day before deadline */
	highwater = now - (GOSSIP_PRUNE_INTERVAL(daemon->rstate->dev_fast_gossip)
			   - GOSSIP_BEFORE_DEADLINE(daemon->rstate->dev_fast_gossip_prune));

	/* Schedule next run now */
	notleak(new_reltimer(&daemon->timers, daemon,
			     time_from_sec(GOSSIP_PRUNE_INTERVAL(daemon->rstate->dev_fast_gossip_prune)/4),
			     gossip_refresh_network, daemon));

	/* Find myself in the network */
	n = get_node(daemon->rstate, &daemon->id);
	if (n) {
		/* Iterate through all outgoing connection and check whether
		 * it's time to re-announce */
		struct chan_map_iter i;
		struct chan *c;

		for (c = first_chan(n, &i); c; c = next_chan(n, &i)) {
			struct half_chan *hc;
			int direction;

			if (!local_direction(daemon->rstate, c, &direction))
				continue;

			hc = &c->half[direction];

			if (!is_halfchan_defined(hc)) {
				/* Connection is not announced yet, so don't even
				 * try to re-announce it */
				continue;
			}

			if (hc->bcast.timestamp > highwater) {
				/* No need to send a keepalive update message */
				continue;
			}

			status_debug("Sending keepalive channel_update"
				     " for %s/%u",
				     type_to_string(tmpctx,
						    struct short_channel_id,
						    &c->scid), direction);
			refresh_local_channel(daemon, c, direction);
		}
	}

	/* Now we've refreshed our channels, we can prune without clobbering
	 * them */
	route_prune(daemon->rstate);
}

/* Disables all channels connected to our node. */
static void gossip_disable_local_channels(struct daemon *daemon)
{
	struct node *local_node = get_node(daemon->rstate, &daemon->id);
	struct chan_map_iter i;
	struct chan *c;

	/* We don't have a local_node, so we don't have any channels yet
	 * either */
	if (!local_node)
		return;

	for (c = first_chan(local_node, &i); c; c = next_chan(local_node, &i))
		local_disable_chan(daemon, c, half_chan_idx(local_node, c));
}

struct peer *random_peer(struct daemon *daemon,
			 bool (*check_peer)(const struct peer *peer))
{
	u64 target = UINT64_MAX;
	struct peer *best = NULL, *i;

	/* Reservoir sampling */
	list_for_each(&daemon->peers, i, list) {
		u64 r;

		if (!check_peer(i))
			continue;

		r = pseudorand_u64();
		if (r <= target) {
			best = i;
			target = r;
		}
	}
	return best;
}

/*~ Parse init message from lightningd: starts the daemon properly. */
static void gossip_init(struct daemon *daemon, const u8 *msg)
{
	u32 *dev_gossip_time;
	bool dev_fast_gossip, dev_fast_gossip_prune;
	u32 timestamp;

	if (!fromwire_gossipd_init(daemon, msg,
				     &chainparams,
				     &daemon->our_features,
				     &daemon->id,
				     daemon->rgb,
				     daemon->alias,
				     &daemon->announcable,
				     &dev_gossip_time,
				     &dev_fast_gossip,
				     &dev_fast_gossip_prune)) {
		master_badmsg(WIRE_GOSSIPD_INIT, msg);
	}

	daemon->rstate = new_routing_state(daemon,
					   &daemon->id,
					   &daemon->peers,
					   &daemon->timers,
					   take(dev_gossip_time),
					   dev_fast_gossip,
					   dev_fast_gossip_prune);

	/* Load stored gossip messages, get last modified time of file */
	timestamp = gossip_store_load(daemon->rstate, daemon->rstate->gs);

	/* If last_timestamp was > modified time of file, reduce it.
	 * Usually it's capped to "now", but in the reload case it needs to
	 * be the gossip_store mtime. */
	if (daemon->rstate->last_timestamp > timestamp)
		daemon->rstate->last_timestamp = timestamp;

	/* Now disable all local channels, they can't be connected yet. */
	gossip_disable_local_channels(daemon);

	/* If that announced channels, we can announce ourselves (options
	 * or addresses might have changed!) */
	maybe_send_own_node_announce(daemon, true);

	/* Start the twice- weekly refresh timer. */
	notleak(new_reltimer(&daemon->timers, daemon,
			     time_from_sec(GOSSIP_PRUNE_INTERVAL(daemon->rstate->dev_fast_gossip_prune) / 4),
			     gossip_refresh_network, daemon));

	/* Fire up the seeker! */
	daemon->seeker = new_seeker(daemon);

	/* connectd is already started, and uses this fd to ask us things. */
	daemon->connectd = daemon_conn_new(daemon, CONNECTD_FD,
					   connectd_req, NULL, daemon);

	/* OK, we are ready. */
	daemon_conn_send(daemon->master,
			 take(towire_gossipd_init_reply(NULL)));
}

static void new_blockheight(struct daemon *daemon, const u8 *msg)
{
	if (!fromwire_gossipd_new_blockheight(msg, &daemon->current_blockheight))
		master_badmsg(WIRE_GOSSIPD_NEW_BLOCKHEIGHT, msg);

	/* Check if we can now send any deferred queries. */
	for (size_t i = 0; i < tal_count(daemon->deferred_txouts); i++) {
		const struct short_channel_id *scid
			= &daemon->deferred_txouts[i];

		if (!is_scid_depth_announceable(scid,
						daemon->current_blockheight))
			continue;

		/* short_channel_id is deep enough, now ask about it. */
		daemon_conn_send(daemon->master,
				 take(towire_gossipd_get_txout(NULL, scid)));

		tal_arr_remove(&daemon->deferred_txouts, i);
		i--;
	}

	daemon_conn_send(daemon->master,
			 take(towire_gossipd_new_blockheight_reply(NULL)));
}

#if DEVELOPER
/* Another testing hack */
static void dev_gossip_suppress(struct daemon *daemon, const u8 *msg)
{
	if (!fromwire_gossipd_dev_suppress(msg))
		master_badmsg(WIRE_GOSSIPD_DEV_SUPPRESS, msg);

	status_unusual("Suppressing all gossip");
	dev_suppress_gossip = true;
}

static void dev_gossip_memleak(struct daemon *daemon, const u8 *msg)
{
	struct htable *memtable;
	bool found_leak;

	memtable = memleak_find_allocations(tmpctx, msg, msg);

	/* Now delete daemon and those which it has pointers to. */
	memleak_remove_region(memtable, daemon, sizeof(*daemon));

	found_leak = dump_memleak(memtable, memleak_status_broken);
	daemon_conn_send(daemon->master,
			 take(towire_gossipd_dev_memleak_reply(NULL,
							      found_leak)));
}

static void dev_compact_store(struct daemon *daemon, const u8 *msg)
{
	bool done = gossip_store_compact(daemon->rstate->gs);

	daemon_conn_send(daemon->master,
			 take(towire_gossipd_dev_compact_store_reply(NULL,
								    done)));
}

static void dev_gossip_set_time(struct daemon *daemon, const u8 *msg)
{
	u32 time;

	if (!fromwire_gossipd_dev_set_time(msg, &time))
		master_badmsg(WIRE_GOSSIPD_DEV_SET_TIME, msg);
	if (!daemon->rstate->gossip_time)
		daemon->rstate->gossip_time = tal(daemon->rstate, struct timeabs);
	daemon->rstate->gossip_time->ts.tv_sec = time;
	daemon->rstate->gossip_time->ts.tv_nsec = 0;
}
#endif /* DEVELOPER */

/*~ We queue incoming channel_announcement pending confirmation from lightningd
 * that it really is an unspent output.  Here's its reply. */
static void handle_txout_reply(struct daemon *daemon, const u8 *msg)
{
	struct short_channel_id scid;
	u8 *outscript;
	struct amount_sat sat;
	bool good;

	if (!fromwire_gossipd_get_txout_reply(msg, msg, &scid, &sat, &outscript))
		master_badmsg(WIRE_GOSSIPD_GET_TXOUT_REPLY, msg);

	/* Outscript is NULL if it's not an unspent output */
	good = handle_pending_cannouncement(daemon, daemon->rstate,
					    &scid, sat, outscript);

	/* If we looking specifically for this, we no longer are. */
	remove_unknown_scid(daemon->seeker, &scid, good);

	/* Anywhere we might have announced a channel, we check if it's time to
	 * announce ourselves (ie. if we just announced our own first channel) */
	maybe_send_own_node_announce(daemon, false);
}

/*~ lightningd tells us when about a gossip message directly, when told to by
 * the addgossip RPC call.  That's usually used when a plugin gets an update
 * returned in an payment error. */
static void inject_gossip(struct daemon *daemon, const u8 *msg)
{
	u8 *goss;
	const u8 *errmsg;
	const char *err;

	if (!fromwire_gossipd_addgossip(msg, msg, &goss))
		master_badmsg(WIRE_GOSSIPD_ADDGOSSIP, msg);

	switch (fromwire_peektype(goss)) {
	case WIRE_CHANNEL_ANNOUNCEMENT:
		errmsg = handle_channel_announcement_msg(daemon, NULL, goss);
		break;
	case WIRE_NODE_ANNOUNCEMENT:
		errmsg = handle_node_announcement(daemon->rstate, goss,
						  NULL, NULL);
		break;
	case WIRE_CHANNEL_UPDATE:
		errmsg = handle_channel_update(daemon->rstate, goss,
					       NULL, NULL, true);
		break;
	default:
		err = tal_fmt(tmpctx, "unknown gossip type %i",
			      fromwire_peektype(goss));
		goto err_extracted;
	}

	/* The APIs above are designed to send error messages back to peers:
	 * we extract the raw string instead. */
	if (errmsg) {
		err = sanitize_error(tmpctx, errmsg, NULL);
		tal_free(errmsg);
	} else
		/* Send empty string if no error. */
		err = "";

err_extracted:
	daemon_conn_send(daemon->master,
			 take(towire_gossipd_addgossip_reply(NULL, err)));
}

static void handle_new_lease_rates(struct daemon *daemon, const u8 *msg)
{
	struct lease_rates *rates = tal(daemon, struct lease_rates);

	if (!fromwire_gossipd_new_lease_rates(msg, rates))
		master_badmsg(WIRE_GOSSIPD_NEW_LEASE_RATES, msg);

	daemon->rates = tal_free(daemon->rates);
	if (!lease_rates_empty(rates))
		daemon->rates = rates;
	else
		tal_free(rates);

	/* Send the update over to the peer */
	maybe_send_own_node_announce(daemon, false);
}

/*~ This is where lightningd tells us that a channel's funding transaction has
 * been spent. */
static void handle_outpoint_spent(struct daemon *daemon, const u8 *msg)
{
	struct short_channel_id scid;
	struct chan *chan;
	struct routing_state *rstate = daemon->rstate;
	if (!fromwire_gossipd_outpoint_spent(msg, &scid))
		master_badmsg(WIRE_GOSSIPD_OUTPOINT_SPENT, msg);

	chan = get_channel(rstate, &scid);
	if (chan) {
		status_debug(
		    "Deleting channel %s due to the funding outpoint being "
		    "spent",
		    type_to_string(msg, struct short_channel_id, &scid));
		/* Suppress any now-obsolete updates/announcements */
		add_to_txout_failures(rstate, &scid);
		remove_channel_from_store(rstate, chan);
		/* Freeing is sufficient since everything else is allocated off
		 * of the channel and this takes care of unregistering
		 * the channel */
		free_chan(rstate, chan);
	}
}

/*~ This is sent by lightningd when it kicks off 'closingd': we disable it
 * in both directions.
 *
 * We'll leave it to handle_outpoint_spent to delete the channel from our view
 * once the close gets confirmed. This avoids having strange states in which the
 * channel is list in our peer list but won't be returned when listing public
 * channels. This does not send out updates since that's triggered by the peer
 * connection closing.
 */
static void handle_local_channel_close(struct daemon *daemon, const u8 *msg)
{
	struct short_channel_id scid;
	struct chan *chan;
	struct routing_state *rstate = daemon->rstate;
	if (!fromwire_gossipd_local_channel_close(msg, &scid))
		master_badmsg(WIRE_GOSSIPD_LOCAL_CHANNEL_CLOSE, msg);

	chan = get_channel(rstate, &scid);
	if (chan) {
		int direction;

		if (!local_direction(rstate, chan, &direction)) {
			status_broken("Non-local channel close %s",
				      type_to_string(tmpctx,
						     struct short_channel_id,
						     &scid));
		} else {
			local_disable_chan(daemon, chan, direction);
		}
	}
}

/*~ This routine handles all the commands from lightningd. */
static struct io_plan *recv_req(struct io_conn *conn,
				const u8 *msg,
				struct daemon *daemon)
{
	enum gossipd_wire t = fromwire_peektype(msg);

	switch (t) {
	case WIRE_GOSSIPD_INIT:
		gossip_init(daemon, msg);
		goto done;

	case WIRE_GOSSIPD_GET_TXOUT_REPLY:
		handle_txout_reply(daemon, msg);
		goto done;

	case WIRE_GOSSIPD_OUTPOINT_SPENT:
		handle_outpoint_spent(daemon, msg);
		goto done;

	case WIRE_GOSSIPD_LOCAL_CHANNEL_CLOSE:
		handle_local_channel_close(daemon, msg);
		goto done;

	case WIRE_GOSSIPD_NEW_BLOCKHEIGHT:
		new_blockheight(daemon, msg);
		goto done;

	case WIRE_GOSSIPD_ADDGOSSIP:
		inject_gossip(daemon, msg);
		goto done;

	case WIRE_GOSSIPD_NEW_LEASE_RATES:
		handle_new_lease_rates(daemon, msg);
		goto done;

	case WIRE_GOSSIPD_GET_ADDRS:
		return handle_get_address(conn, daemon, msg);

	case WIRE_GOSSIPD_USED_LOCAL_CHANNEL_UPDATE:
		handle_used_local_channel_update(daemon, msg);
		goto done;

#if DEVELOPER
	case WIRE_GOSSIPD_DEV_SET_MAX_SCIDS_ENCODE_SIZE:
		dev_set_max_scids_encode_size(daemon, msg);
		goto done;
	case WIRE_GOSSIPD_DEV_SUPPRESS:
		dev_gossip_suppress(daemon, msg);
		goto done;
	case WIRE_GOSSIPD_DEV_MEMLEAK:
		dev_gossip_memleak(daemon, msg);
		goto done;
	case WIRE_GOSSIPD_DEV_COMPACT_STORE:
		dev_compact_store(daemon, msg);
		goto done;
	case WIRE_GOSSIPD_DEV_SET_TIME:
		dev_gossip_set_time(daemon, msg);
		goto done;
#else
	case WIRE_GOSSIPD_DEV_SET_MAX_SCIDS_ENCODE_SIZE:
	case WIRE_GOSSIPD_DEV_SUPPRESS:
	case WIRE_GOSSIPD_DEV_MEMLEAK:
	case WIRE_GOSSIPD_DEV_COMPACT_STORE:
	case WIRE_GOSSIPD_DEV_SET_TIME:
		break;
#endif /* !DEVELOPER */

	case WIRE_GOSSIPD_SEND_ONIONMSG:
		onionmsg_req(daemon, msg);
		goto done;

	/* We send these, we don't receive them */
	case WIRE_GOSSIPD_INIT_REPLY:
	case WIRE_GOSSIPD_GET_TXOUT:
	case WIRE_GOSSIPD_DEV_MEMLEAK_REPLY:
	case WIRE_GOSSIPD_DEV_COMPACT_STORE_REPLY:
	case WIRE_GOSSIPD_GOT_ONIONMSG_TO_US:
	case WIRE_GOSSIPD_ADDGOSSIP_REPLY:
	case WIRE_GOSSIPD_NEW_BLOCKHEIGHT_REPLY:
	case WIRE_GOSSIPD_GET_ADDRS_REPLY:
	case WIRE_GOSSIPD_GOT_LOCAL_CHANNEL_UPDATE:
		break;
	}

	/* Master shouldn't give bad requests. */
	status_failed(STATUS_FAIL_MASTER_IO, "%i: %s",
		      t, tal_hex(tmpctx, msg));

done:
	return daemon_conn_read_next(conn, daemon->master);
}

/* This is called when lightningd closes its connection to us.  We simply
 * exit. */
static void master_gone(struct daemon_conn *master UNUSED)
{
	daemon_shutdown();
	/* Can't tell master, it's gone. */
	exit(2);
}

int main(int argc, char *argv[])
{
	setup_locale();

	struct daemon *daemon;

	subdaemon_setup(argc, argv);

	daemon = tal(NULL, struct daemon);
	list_head_init(&daemon->peers);
	daemon->deferred_txouts = tal_arr(daemon, struct short_channel_id, 0);
	daemon->node_announce_timer = NULL;
	daemon->current_blockheight = 0; /* i.e. unknown */
	daemon->rates = NULL;
	list_head_init(&daemon->deferred_updates);

	/* Tell the ecdh() function how to talk to hsmd */
	ecdh_hsmd_setup(HSM_FD, status_failed);

	/* Note the use of time_mono() here.  That's a monotonic clock, which
	 * is really useful: it can only be used to measure relative events
	 * (there's no correspondence to time-since-Ken-grew-a-beard or
	 * anything), but unlike time_now(), this will never jump backwards by
	 * half a second and leave me wondering how my tests failed CI! */
	timers_init(&daemon->timers, time_mono());

	/* Our daemons always use STDIN for commands from lightningd. */
	daemon->master = daemon_conn_new(daemon, STDIN_FILENO,
					 recv_req, NULL, daemon);
	tal_add_destructor(daemon->master, master_gone);

	status_setup_async(daemon->master);

	/* This loop never exits.  io_loop() only returns if a timer has
	 * expired, or io_break() is called, or all fds are closed.  We don't
	 * use io_break and closing the lightningd fd calls master_gone()
	 * which exits. */
	for (;;) {
		struct timer *expired = NULL;
		io_loop(&daemon->timers, &expired);

		timer_expired(expired);
	}
}

/*~ Note that the actual routing stuff is in routing.c; you might want to
 * check that out later.
 *
 * But that's the last of the global daemons.  We now move on to the first of
 * the per-peer daemons: openingd/openingd.c.
 */