config: adds htlc_minimum_msat htlc_maximum_msat announce_discovered_ip

This adds config and commandline options for htlc_min_msat, htlc_max_msat and
announce_discovered_ip. The default is 0msat for htlc_min_msat, unlimited for
htlc_max_msat and enabled for announce_discovered_ip.

The announce_discovered_ip gets the disable commandline switch --disable-ip-discovery

Changelog-added: Config options for htlc_min_msat, htlc_max_msat and announce_discovered_ip.

lightningd/lightningd.h

@@ -33,6 +33,10 @@ struct config {
 	/* htlcs per channel */
 	u32 max_concurrent_htlcs;
 
+	/* htlc min/max values */
+	struct amount_msat htlc_minimum_msat;
+	struct amount_msat htlc_maximum_msat;
+
 	/* Max amount of dust allowed per channel */
 	struct amount_msat max_dust_htlc_exposure_msat;
 
@@ -52,6 +56,9 @@ struct config {
 	/* Are we allowed to use DNS lookup for peers. */
 	bool use_dns;
 
+	/* Turn off IP address announcement discovered via peer `remote_addr` */
+	bool disable_ip_discovery;
+
 	/* Minimal amount of effective funding_satoshis for accepting channels */
 	u64 min_capacity_sat;
 

lightningd/opening_common.c

@@ -147,7 +147,7 @@ void channel_config(struct lightningd *ld,
 		= ld->config.max_dust_htlc_exposure_msat;
 
 	/* Don't care */
-	ours->htlc_minimum = AMOUNT_MSAT(0);
+	ours->htlc_minimum = ld->config.htlc_minimum_msat;
 
 	/* BOLT #2:
 	 *

lightningd/opening_control.c

@@ -211,8 +211,8 @@ wallet_commit_channel(struct lightningd *ld,
 			      take(new_height_states(NULL, uc->fc ? LOCAL : REMOTE,
 						     &lease_start_blockheight)),
 			      0, NULL, 0, 0, /* No leases on v1s */
-			      AMOUNT_MSAT(0), /* No htlc_minimum_msat */
-			      AMOUNT_MSAT(-1ULL)); /* No htlc_maximum_msat */
+			      ld->config.htlc_minimum_msat,
+			      ld->config.htlc_maximum_msat);
 
 	/* Now we finally put it in the database. */
 	wallet_channel_insert(ld->wallet, channel);

lightningd/options.c

@@ -760,6 +760,10 @@ static const struct config testnet_config = {
 	/* Testnet blockspace is free. */
 	.max_concurrent_htlcs = 483,
 
+	/* channel defaults for htlc min/max values */
+	.htlc_minimum_msat = AMOUNT_MSAT(0),
+	.htlc_maximum_msat = AMOUNT_MSAT(-1ULL),  /* no limit */
+
 	/* Max amount of dust allowed per channel (50ksat) */
 	.max_dust_htlc_exposure_msat = AMOUNT_MSAT(50000000),
 
@@ -783,6 +787,9 @@ static const struct config testnet_config = {
 
 	.use_dns = true,
 
+	/* Turn off IP address announcement discovered via peer `remote_addr` */
+	.disable_ip_discovery = false,
+
 	/* Sets min_effective_htlc_capacity - at 1000$/BTC this is 10ct */
 	.min_capacity_sat = 10000,
 
@@ -809,6 +816,10 @@ static const struct config mainnet_config = {
 	/* While up to 483 htlcs are possible we do 30 by default (as eclair does) to save blockspace */
 	.max_concurrent_htlcs = 30,
 
+	/* defaults for htlc min/max values */
+	.htlc_minimum_msat = AMOUNT_MSAT(0),
+	.htlc_maximum_msat = AMOUNT_MSAT(-1ULL),  /* no limit */
+
 	/* Max amount of dust allowed per channel (50ksat) */
 	.max_dust_htlc_exposure_msat = AMOUNT_MSAT(50000000),
 
@@ -842,6 +853,9 @@ static const struct config mainnet_config = {
 
 	.use_dns = true,
 
+	/* Turn off IP address announcement discovered via peer `remote_addr` */
+	.disable_ip_discovery = false,
+
 	/* Sets min_effective_htlc_capacity - at 1000$/BTC this is 10ct */
 	.min_capacity_sat = 10000,
 
@@ -1105,6 +1119,12 @@ static void register_opts(struct lightningd *ld)
 	opt_register_arg("--fee-per-satoshi", opt_set_u32, opt_show_u32,
 			 &ld->config.fee_per_satoshi,
 			 "Microsatoshi fee for every satoshi in HTLC");
+	opt_register_arg("--htlc-minimum-msat", opt_set_msat, NULL,
+			 &ld->config.htlc_minimum_msat,
+			 "The default minimal value an HTLC must carry in order to be forwardable for new channels");
+	opt_register_arg("--htlc-maximum-msat", opt_set_msat, NULL,
+			 &ld->config.htlc_maximum_msat,
+			 "The default maximal value an HTLC must carry in order to be forwardable for new channel");
 	opt_register_arg("--max-concurrent-htlcs", opt_set_u32, opt_show_u32,
 			 &ld->config.max_concurrent_htlcs,
 			 "Number of HTLCs one channel can handle concurrently. Should be between 1 and 483");
@@ -1123,6 +1143,9 @@ static void register_opts(struct lightningd *ld)
 	opt_register_arg("--announce-addr", opt_add_announce_addr, NULL,
 			 ld,
 			 "Set an IP address (v4 or v6) or .onion v3 to announce, but not listen on");
+	opt_register_noarg("--disable-ip-discovery", opt_set_bool,
+			 &ld->config.disable_ip_discovery,
+			 "Turn off announcement of discovered public IPs");
 
 	opt_register_noarg("--offline", opt_set_offline, ld,
 			   "Start in offline-mode (do not automatically reconnect and do not accept incoming connections)");

lightningd/peer_control.c

@@ -1076,7 +1076,7 @@ static void update_remote_addr(struct lightningd *ld,
 			       const struct node_id peer_id)
 {
 	/* failsafe to prevent privacy leakage. */
-	if (ld->always_use_proxy)
+	if (ld->always_use_proxy || ld->config.disable_ip_discovery)
 		return;
 
 	switch (remote_addr->type) {