daemon: config file support.

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

daemon/lightningd.c

@@ -13,6 +13,7 @@
 #include <ccan/tal/tal.h>
 #include <ccan/timer/timer.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
@@ -20,6 +21,93 @@
 #include <unistd.h>
 #include <version.h>
 
+static char *opt_set_u64(const char *arg, u64 *u)
+{
+	char *endp;
+	unsigned long long l;
+
+	/* This is how the manpage says to do it.  Yech. */
+	errno = 0;
+	l = strtoull(arg, &endp, 0);
+	if (*endp || !arg[0])
+		return tal_fmt(NULL, "'%s' is not a number", arg);
+	*u = l;
+	if (errno || *u != l)
+		return tal_fmt(NULL, "'%s' is out of range", arg);
+	return NULL;
+}
+
+static char *opt_set_u32(const char *arg, u32 *u)
+{
+	char *endp;
+	unsigned long l;
+
+	/* This is how the manpage says to do it.  Yech. */
+	errno = 0;
+	l = strtoul(arg, &endp, 0);
+	if (*endp || !arg[0])
+		return tal_fmt(NULL, "'%s' is not a number", arg);
+	*u = l;
+	if (errno || *u != l)
+		return tal_fmt(NULL, "'%s' is out of range", arg);
+	return NULL;
+}
+
+static void opt_show_u64(char buf[OPT_SHOW_LEN], const u64 *u)
+{
+	snprintf(buf, OPT_SHOW_LEN, "%"PRIu64, *u);
+}
+
+static void opt_show_u32(char buf[OPT_SHOW_LEN], const u32 *u)
+{
+	snprintf(buf, OPT_SHOW_LEN, "%"PRIu32, *u);
+}
+
+static void config_register_opts(struct lightningd_state *state)
+{
+	opt_register_arg("--locktime", opt_set_u32, opt_show_u32,
+			 &state->config.rel_locktime,
+			 "Seconds before peer can unilaterally spend funds");
+	opt_register_arg("--max-locktime", opt_set_u32, opt_show_u32,
+			 &state->config.rel_locktime_max,
+			 "Maximum seconds peer can lock up our funds");
+	opt_register_arg("--anchor-confirms", opt_set_u32, opt_show_u32,
+			 &state->config.anchor_confirms,
+			 "Confirmations required for anchor transaction");
+	opt_register_arg("--max-anchor-confirms", opt_set_u32, opt_show_u32,
+			 &state->config.anchor_confirms_max,
+			 "Maximum confirmations other side can wait for anchor transaction");
+	opt_register_arg("--commit-fee", opt_set_u64, opt_show_u64,
+			 &state->config.commitment_fee,
+			 "Satoshis to offer for commitment transaction fee");
+	opt_register_arg("--min-commit-fee", opt_set_u64, opt_show_u64,
+			 &state->config.commitment_fee_min,
+			 "Minimum satoshis to accept for commitment transaction fee");
+}
+
+static void default_config(struct config *config)
+{
+	/* One day to catch cheating attempts. */
+	config->rel_locktime = 60 * 60 * 24;
+
+	/* They can have up to 3 days. */
+	config->rel_locktime_max = 60 * 60 * 24 * 3;
+
+	/* We're fairly trusting, under normal circumstances. */
+	config->anchor_confirms = 3;
+
+	/* More than 10 confirms seems overkill. */
+	config->anchor_confirms_max = 10;
+
+	/* FIXME: These should float with bitcoind's recommendations! */
+
+	/* Pay hefty fee (10x current suggested minimum). */
+	config->commitment_fee = 50000;
+
+	/* Don't accept less than double the current standard fee. */
+	config->commitment_fee_min = 10000;
+}
+
 static struct lightningd_state *lightningd_state(void)
 {
 	struct lightningd_state *state = tal(NULL, struct lightningd_state);
@@ -32,6 +120,7 @@ static struct lightningd_state *lightningd_state(void)
 	timers_init(&state->timers, time_now());
 	state->secpctx = secp256k1_context_create(SECP256K1_CONTEXT_VERIFY
 						  | SECP256K1_CONTEXT_SIGN);
+	default_config(&state->config);
 	return state;
 }
 
@@ -74,6 +163,7 @@ int main(int argc, char *argv[])
 
 	configdir_register_opts(state,
 				&state->config_dir, &state->rpc_filename);
+	config_register_opts(state);
 
 	/* Get any configdir options first. */
 	opt_early_parse(argc, argv, opt_log_stderr_exit);

daemon/lightningd.h

@@ -3,10 +3,32 @@
 #include "config.h"
 #include "bitcoin/pubkey.h"
 #include <ccan/list/list.h>
+#include <ccan/short_types/short_types.h>
 #include <ccan/timer/timer.h>
 #include <secp256k1.h>
 #include <stdio.h>
 
+/* Various adjustable things. */
+struct config {
+	/* How long do we want them to lock up their funds? (seconds) */
+	u32 rel_locktime;
+
+	/* How long do we let them lock up our funds? (seconds) */
+	u32 rel_locktime_max;
+
+	/* How many confirms until we consider an anchor "settled". */
+	u32 anchor_confirms;
+
+	/* How long will we accept them waiting? */
+	u32 anchor_confirms_max;
+
+	/* What are we prepared to pay in commitment fee (satoshis). */
+	u64 commitment_fee;
+
+	/* How little are we prepared to have them pay? */
+	u64 commitment_fee_min;
+};
+
 /* Here's where the global variables hide! */
 struct lightningd_state {
 	/* Where all our logging goes. */ 
@@ -18,6 +40,9 @@ struct lightningd_state {
 	char *config_dir;
 	char *rpc_filename;
 
+	/* Configuration settings. */
+	struct config config;
+
 	/* Any pending timers. */
 	struct timers timers;