channel_config: convenient structure for handling open/accept config info.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/Makefile

@@ -27,6 +27,7 @@ LIGHTNINGD_OLD_OBJS := $(LIGHTNINGD_OLD_SRC:.c=.o)
 LIGHTNINGD_OLD_HEADERS := $(LIGHTNINGD_OLD_SRC:.c=.h)
 
 LIGHTNINGD_LIB_SRC :=				\
+	lightningd/channel_config.c		\
 	lightningd/cryptomsg.c			\
 	lightningd/key_derive.c
 

lightningd/channel_config.c

@@ -0,0 +1,31 @@
+#include <lightningd/channel_config.h>
+#include <wire/wire.h>
+
+void towire_channel_config(u8 **pptr, const struct channel_config *config)
+{
+	towire_u64(pptr, config->dust_limit_satoshis);
+	towire_u64(pptr, config->max_htlc_value_in_flight_msat);
+	towire_u64(pptr, config->channel_reserve_satoshis);
+	towire_u32(pptr, config->minimum_depth);
+	towire_u32(pptr, config->htlc_minimum_msat);
+	towire_u16(pptr, config->to_self_delay);
+	towire_u16(pptr, config->max_accepted_htlcs);
+}
+
+struct channel_config *fromwire_channel_config(const tal_t *ctx,
+				       const u8 **ptr, size_t *max)
+{
+	struct channel_config *config = tal(ctx, struct channel_config);
+
+	config->dust_limit_satoshis = fromwire_u64(ptr, max);
+	config->max_htlc_value_in_flight_msat = fromwire_u64(ptr, max);
+	config->channel_reserve_satoshis = fromwire_u64(ptr, max);
+	config->minimum_depth = fromwire_u32(ptr, max);
+	config->htlc_minimum_msat = fromwire_u32(ptr, max);
+	config->to_self_delay = fromwire_u16(ptr, max);
+	config->max_accepted_htlcs = fromwire_u16(ptr, max);
+
+	if (!*ptr)
+		return tal_free(config);
+	return config;
+}

lightningd/channel_config.h

@@ -0,0 +1,46 @@
+#ifndef LIGHTNING_LIGHTNINGD_CHANNEL_CONFIG_H
+#define LIGHTNING_LIGHTNINGD_CHANNEL_CONFIG_H
+#include "config.h"
+#include <ccan/short_types/short_types.h>
+#include <ccan/tal/tal.h>
+
+/* BOLT #2:
+ *
+ * 1. type: 32 (`open_channel`)
+ * 2. data:
+ *    * [8:temporary-channel-id]
+ *    * [8:funding-satoshis]
+ *    * [8:push-msat]
+ *    * [8:dust-limit-satoshis]
+ *    * [8:max-htlc-value-in-flight-msat]
+ *    * [8:channel-reserve-satoshis]
+ *    * [4:htlc-minimum-msat]
+ *    * [4:feerate-per-kw]
+ *    * [2:to-self-delay]
+ *    * [2:max-accepted-htlcs]
+ *...
+ * 1. type: 33 (`accept_channel`)
+ * 2. data:
+ *    * [8:temporary-channel-id]
+ *    * [8:dust-limit-satoshis]
+ *    * [8:max-htlc-value-in-flight-msat]
+ *    * [8:channel-reserve-satoshis]
+ *    * [4:minimum-depth]
+ *    * [4:htlc-minimum-msat]
+ *    * [2:to-self-delay]
+ *    * [2:max-accepted-htlcs]
+ */
+struct channel_config {
+	u64 dust_limit_satoshis;
+	u64 max_htlc_value_in_flight_msat;
+	u64 channel_reserve_satoshis;
+	u32 minimum_depth;
+	u32 htlc_minimum_msat;
+	u16 to_self_delay;
+	u16 max_accepted_htlcs;
+};
+
+void towire_channel_config(u8 **pptr, const struct channel_config *config);
+struct channel_config *fromwire_channel_config(const tal_t *ctx,
+					       const u8 **ptr, size_t *max);
+#endif /* LIGHTNING_LIGHTNINGD_CHANNEL_CONFIG_H */