Function handle_onion_message

connectd/onion_message.c:39–186

Peer sends an onion msg. */

/* Peer sends an onion msg. */
void handle_onion_message(struct daemon *daemon,
			  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(daemon->our_features->bits[NODE_ANNOUNCE_FEATURE],
			     OPT_ONION_MESSAGES))
		return;

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

	/* 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;
	}

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

	/* 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;
	}

	/* 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;