lightningd/runes: Added last_time_check for validating rune for per…

… restriction

Changelog-Added: runes: `per=Nsec/min/hour/msec/usec/nsec` for general ratelimiting

doc/lightning-createrune.7.md

@@ -36,6 +36,7 @@ being run:
 * id: the node\_id of the peer, e.g. "id=024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605".
 * method: the command being run, e.g. "method=withdraw".
 * rate: the rate limit, per minute, e.g. "rate=60".
+* per: how often the rune can be used, with suffix "sec" (default), "min", "hour", "day" or "msec", "usec" or "nsec". e.g. "per=5sec".
 * pnum: the number of parameters. e.g. "pnum<2".
 * pnameX: the parameter named X (with any punctuation like `_` removed). e.g. "pnamedestination=1RustyRX2oai4EYYDpQGWvEL62BBGqN9T".
 * parrN: the N'th parameter. e.g. "parr0=1RustyRX2oai4EYYDpQGWvEL62BBGqN9T".

lightningd/runes.c

@@ -8,6 +8,7 @@
 #include <common/json_param.h>
 #include <common/json_stream.h>
 #include <common/memleak.h>
+#include <common/overflows.h>
 #include <common/timeout.h>
 #include <common/type_to_string.h>
 #include <db/exec.h>
@@ -45,6 +46,7 @@ struct cond_info {
 	const struct node_id *peer;
 	const char *buf;
 	const char *method;
+	struct timeabs now;
 	const jsmntok_t *params;
 	STRMAP(const jsmntok_t *) cached_params;
 	struct usage *usage;
@@ -114,6 +116,58 @@ u64 rune_unique_id(const struct rune *rune)
 	return num;
 }
 
+static const char *last_time_check(const tal_t *ctx,
+				    const struct runes *runes,
+				    const struct rune *rune,
+				    const struct rune_altern *alt,
+				    struct cond_info *cinfo)
+{
+	u64 r, multiplier, diff;
+	struct timeabs last_used;
+	char *endp;
+	const u64 sec_per_nsec = 1000000000;
+
+	if (alt->condition != '=')
+		return "per operator must be =";
+
+	r = strtoul(alt->value, &endp, 10);
+	if (endp == alt->value || r == 0 || r >= UINT32_MAX)
+		return "malformed per";
+	if (streq(endp, "") || streq(endp, "sec")) {
+		multiplier = sec_per_nsec;
+	} else if (streq(endp, "nsec")) {
+		multiplier = 1;
+	} else if (streq(endp, "usec")) {
+		multiplier = 1000;
+	} else if (streq(endp, "msec")) {
+		multiplier = 1000000;
+	} else if (streq(endp, "min")) {
+		multiplier = 60 * sec_per_nsec;
+	} else if (streq(endp, "hour")) {
+		multiplier = 60 * 60 * sec_per_nsec;
+	} else if (streq(endp, "day")) {
+		multiplier = 24 * 60 * 60 * sec_per_nsec;
+	} else {
+		return "malformed suffix";
+	}
+	if (mul_overflows_u64(r, multiplier)) {
+		return "per overflow";
+	}
+	if (!wallet_get_rune(tmpctx, cinfo->runes->ld->wallet, atol(rune->unique_id), &last_used)) {
+		/* FIXME: If we do not know the rune, per does not work */
+		return NULL;
+	}
+	if (time_before(cinfo->now, last_used)) {
+		last_used = cinfo->now;
+	}
+	diff = time_to_nsec(time_between(cinfo->now, last_used));
+
+	if (diff < (r * multiplier)) {
+		return "too soon";
+	}
+	return NULL;
+}
+
 static const char *rate_limit_check(const tal_t *ctx,
 				    const struct runes *runes,
 				    const struct rune *rune,
@@ -722,7 +776,7 @@ static const char *check_condition(const tal_t *ctx,
 	const jsmntok_t *ptok;
 
 	if (streq(alt->fieldname, "time")) {
-		return rune_alt_single_int(ctx, alt, time_now().ts.tv_sec);
+		return rune_alt_single_int(ctx, alt, cinfo->now.ts.tv_sec);
 	} else if (streq(alt->fieldname, "id")) {
 		if (cinfo->peer) {
 			const char *id = node_id_to_hexstr(tmpctx, cinfo->peer);
@@ -739,6 +793,8 @@ static const char *check_condition(const tal_t *ctx,
 		return rune_alt_single_int(ctx, alt, (cinfo && cinfo->params) ? cinfo->params->size : 0);
 	} else if (streq(alt->fieldname, "rate")) {
 		return rate_limit_check(ctx, cinfo->runes, rune, alt, cinfo);
+	} else if (streq(alt->fieldname, "per")) {
+		return last_time_check(ctx, cinfo->runes, rune, alt, cinfo);
 	}
 
 	/* Rest are params looksup: generate this once! */
@@ -791,9 +847,9 @@ static const char *check_condition(const tal_t *ctx,
 }
 
 static void update_rune_usage_time(struct runes *runes,
-						 struct rune *rune)
+						 struct rune *rune, struct timeabs now)
 {
-	wallet_rune_update_last_used(runes->ld->wallet, rune, time_now());
+	wallet_rune_update_last_used(runes->ld->wallet, rune, now);
 }
 
 static struct command_result *json_checkrune(struct command *cmd,
@@ -824,6 +880,7 @@ static struct command_result *json_checkrune(struct command *cmd,
 	cinfo.buf = buffer;
 	cinfo.method = method;
 	cinfo.params = methodparams;
+	cinfo.now = time_now();
 	/* We will populate it in rate_limit_check if required. */
 	cinfo.usage = NULL;
 	strmap_init(&cinfo.cached_params);
@@ -845,7 +902,7 @@ static struct command_result *json_checkrune(struct command *cmd,
 	/* If it succeeded, *now* we increment any associated usage counter. */
 	if (cinfo.usage)
 		cinfo.usage->counter++;
-	update_rune_usage_time(cmd->ld->runes, ras->rune);
+	update_rune_usage_time(cmd->ld->runes, ras->rune, cinfo.now);
 
 	js = json_stream_success(cmd);
 	json_add_bool(js, "valid", true);