Function extract_channel_id

wire/peer_wire.c:148–426

Extract channel_id from various packets, return true if possible. */

/* Extract channel_id from various packets, return true if possible. */
bool extract_channel_id(const u8 *in_pkt, struct channel_id *channel_id)
{
	const u8 *cursor = in_pkt;
	size_t max = tal_bytelen(in_pkt);
	enum peer_wire t;

	t = fromwire_u16(&cursor, &max);

	/* We carefully quote bolts here, in case anything changes! */
	switch (t) {
	/* These ones don't have a channel_id */
	case WIRE_INIT:
	case WIRE_PING:
	case WIRE_PONG:
	case WIRE_CHANNEL_ANNOUNCEMENT:
	case WIRE_NODE_ANNOUNCEMENT:
	case WIRE_CHANNEL_UPDATE:
	case WIRE_QUERY_SHORT_CHANNEL_IDS:
	case WIRE_REPLY_SHORT_CHANNEL_IDS_END:
	case WIRE_QUERY_CHANNEL_RANGE:
	case WIRE_REPLY_CHANNEL_RANGE:
	case WIRE_GOSSIP_TIMESTAMP_FILTER:
	case WIRE_ONION_MESSAGE:
	case WIRE_PEER_STORAGE:
	case WIRE_PEER_STORAGE_RETRIEVAL:
	case WIRE_PROTOCOL_BATCH_ELEMENT:
		return false;

	/* Special cases: */
	case WIRE_ERROR:
		/* BOLT #1:
		 * 1. type: 17 (`error`)
		 * 2. data:
		 *    * [`channel_id`:`channel_id`]
		 */
		/* fall thru */
	case WIRE_WARNING:
		/* BOLT #1:
		 * 1. type: 1 (`warning`)
		 * 2. data:
		 *    * [`channel_id`:`channel_id`]
		 */
		/* BOLT #1:
		 *
		 * The channel is referred to by `channel_id`, unless
		 * `channel_id` is 0
		 */
		if (!fromwire_channel_id(&cursor, &max, channel_id))
			return false;
		if (memeqzero(channel_id->id, sizeof(channel_id->id)))
			return false;
		return true;

	case WIRE_OPEN_CHANNEL:
		/* BOLT #2:
		 * 1. type: 32 (`open_channel`)
		 * 2. data:
		 *    * [`chain_hash`:`chain_hash`]