Function sigcheck_channel_update

gossipd/sigcheck.c:9–43

Verify the signature of a channel_update message */

/* Verify the signature of a channel_update message */
const char *sigcheck_channel_update(const tal_t *ctx,
				    const struct node_id *node_id,
				    const secp256k1_ecdsa_signature *node_sig,
				    const u8 *update)
{
	/* BOLT #7:
	 * 1. type: 258 (`channel_update`)
	 * 2. data:
	 *     * [`signature`:`signature`]
	 *     * [`chain_hash`:`chain_hash`]
	 *     * [`short_channel_id`:`short_channel_id`]
	 *     * [`u32`:`timestamp`]
	 *     * [`byte`:`message_flags`]
	 *     * [`byte`:`channel_flags`]
	 *     * [`u16`:`cltv_expiry_delta`]
	 *     * [`u64`:`htlc_minimum_msat`]
	 *     * [`u32`:`fee_base_msat`]
	 *     * [`u32`:`fee_proportional_millionths`]
	 *     * [`u64`:`htlc_maximum_msat`]
	 */
	/* 2 byte msg type + 64 byte signatures */
	int offset = 66;
	struct sha256_double hash;

	sha256_double(&hash, update + offset, tal_count(update) - offset);

	if (!check_signed_hash_nodeid(&hash, node_sig, node_id))
		return tal_fmt(ctx,
			       "Bad signature for %s hash %s"
			       " on channel_update %s",
			       fmt_secp256k1_ecdsa_signature(tmpctx, node_sig),
			       fmt_sha256_double(tmpctx, &hash),
			       tal_hex(tmpctx, update));
	return NULL;
}

const char *sigcheck_channel_announcement(const tal_t *ctx,
					  const struct node_id *node1_id,