bolt7: dns support

.gitignore

@@ -51,7 +51,6 @@ contrib/pyln-*/.eggs/
 contrib/pyln-*/pyln/*/__version__.py
 release/
 tests/plugins/test_selfdisable_after_getmanifest
-.DS_Store
 
 # Ignore generated files
 devtools/features
@@ -60,3 +59,7 @@ doc/lightning*.[1578]
 *_wiregen.[ch]
 *_printgen.[ch]
 *_gettextgen.po
+
+# Ignore unrelated stuff
+.DS_Store
+.gdb_history

common/json_helpers.c

@@ -281,6 +281,10 @@ void json_add_address(struct json_stream *response, const char *fieldname,
 		json_add_string(response, "type", "torv3");
 		json_add_string(response, "address", fmt_wireaddr_without_port(tmpctx, addr));
 		json_add_num(response, "port", addr->port);
+	} else if (addr->type == ADDR_TYPE_DNS) {
+		json_add_string(response, "type", "dns");
+		json_add_string(response, "address", fmt_wireaddr_without_port(tmpctx, addr));
+		json_add_num(response, "port", addr->port);
 	} else if (addr->type == ADDR_TYPE_WEBSOCKET) {
 		json_add_string(response, "type", "websocket");
 		json_add_num(response, "port", addr->port);

common/test/run-ip_port_parsing.c

@@ -117,6 +117,26 @@ int main(int argc, char *argv[])
 
 	common_setup(argv[0]);
 
+	/* Check IP/TOR/DNS parser */
+	assert(is_ipaddr("192.168.1.2"));
+	assert(!is_ipaddr("foo.bar.1.2"));
+	assert(is_toraddr("qubesosfasa4zl44o4tws22di6kepyzfeqv3tg4e3ztknltfxqrymdad.onion"));
+	assert(is_toraddr("qubesos4rrrrz6n4.onion"));
+	assert(!is_toraddr("QUBESOSfasa4zl44o4tws22di6kepyzfeqv3tg4e3ztknltfxqrymdad.onion"));
+	assert(!is_toraddr("QUBESOS4rrrrz6n4.onion"));
+	assert(!is_toraddr("qubesos-asa4zl44o4tws22di6kepyzfeqv3tg4e3ztknltfxqrymdad.onion"));
+	assert(is_dnsaddr("example.com"));
+	assert(is_dnsaddr("example.digits123.com"));
+	assert(is_dnsaddr("example-hyphen.com"));
+	assert(is_dnsaddr("123example.com"));
+	assert(is_dnsaddr("example123.com"));
+	assert(is_dnsaddr("is-valid.3hostname123.com"));
+	assert(!is_dnsaddr("UPPERCASE.invalid.com"));
+	assert(!is_dnsaddr("-.invalid.com"));
+	assert(!is_dnsaddr("invalid.-example.com"));
+	assert(!is_dnsaddr("invalid.example-.com"));
+	assert(!is_dnsaddr("invalid..example.com"));
+
 	/* Grossly invalid. */
 	assert(!separate_address_and_port(tmpctx, "[", &ip, &port));
 	assert(!separate_address_and_port(tmpctx, "[123", &ip, &port));
@@ -148,6 +168,19 @@ int main(int argc, char *argv[])
 	assert(streq(ip, "192.168.2.255"));
 	assert(port == 0);
 
+	/* DNS types */
+	assert(separate_address_and_port(tmpctx, "example.com:42", &ip, &port));
+	assert(streq(ip, "example.com"));
+	assert(port == 42);
+	assert(separate_address_and_port(tmpctx, "sub.example.com:21", &ip, &port));
+	assert(streq(ip, "sub.example.com"));
+	assert(port == 21);
+	port = 123;
+	assert(separate_address_and_port(tmpctx, "sub.example.com", &ip, &port));
+	assert(streq(ip, "sub.example.com"));
+	assert(port == 123);
+	port = 0;
+
 	// unusual but possibly valid case
 	assert(separate_address_and_port(tmpctx, "[::1]", &ip, &port));
 	assert(streq(ip, "::1"));

common/wireaddr.c

@@ -37,6 +37,11 @@ bool fromwire_wireaddr(const u8 **cursor, size_t *max, struct wireaddr *addr)
 	case ADDR_TYPE_TOR_V3:
 		addr->addrlen = TOR_V3_ADDRLEN;
 		break;
+	case ADDR_TYPE_DNS:
+		addr->addrlen = fromwire_u8(cursor, max);
+		memset(&addr->addr, 0, sizeof(addr->addr));
+		addr->addr[addr->addrlen] = 0;
+		break;
 	case ADDR_TYPE_WEBSOCKET:
 		addr->addrlen = 0;
 		break;
@@ -52,6 +57,8 @@ bool fromwire_wireaddr(const u8 **cursor, size_t *max, struct wireaddr *addr)
 void towire_wireaddr(u8 **pptr, const struct wireaddr *addr)
 {
 	towire_u8(pptr, addr->type);
+	if (addr->type == ADDR_TYPE_DNS)
+		towire_u8(pptr, addr->addrlen);
 	towire(pptr, addr->addr, addr->addrlen);
 	towire_u16(pptr, addr->port);
 }
@@ -211,6 +218,7 @@ bool wireaddr_is_wildcard(const struct wireaddr *addr)
 		return memeqzero(addr->addr, addr->addrlen);
 	case ADDR_TYPE_TOR_V2_REMOVED:
 	case ADDR_TYPE_TOR_V3:
+	case ADDR_TYPE_DNS:
 	case ADDR_TYPE_WEBSOCKET:
 		return false;
 	}
@@ -259,6 +267,8 @@ char *fmt_wireaddr_without_port(const tal_t * ctx, const struct wireaddr *a)
 	case ADDR_TYPE_TOR_V3:
 		return tal_fmt(ctx, "%s.onion",
 			       b32_encode(tmpctx, a->addr, a->addrlen));
+	case ADDR_TYPE_DNS:
+		return tal_fmt(ctx, "%s", a->addr);
 	case ADDR_TYPE_WEBSOCKET:
 		return tal_strdup(ctx, "websocket");
 	}
@@ -287,8 +297,8 @@ REGISTER_TYPE_TO_STRING(wireaddr, fmt_wireaddr);
  * Returns false if it wasn't one of these forms.  If it returns true,
  * it only overwrites *port if it was specified by <number> above.
  */
-static bool separate_address_and_port(const tal_t *ctx, const char *arg,
-				      char **addr, u16 *port)
+bool separate_address_and_port(const tal_t *ctx, const char *arg,
+			       char **addr, u16 *port)
 {
 	char *portcolon;
 
@@ -322,6 +332,81 @@ static bool separate_address_and_port(const tal_t *ctx, const char *arg,
 	return true;
 }
 
+bool is_ipaddr(const char *arg)
+{
+	struct in_addr v4;
+	struct in6_addr v6;
+	if (inet_pton(AF_INET, arg, &v4))
+		return true;
+	if (inet_pton(AF_INET6, arg, &v6))
+		return true;
+	return false;
+}
+
+bool is_toraddr(const char *arg)
+{
+	size_t i, arglen;
+	arglen = strlen(arg);
+	if (!strends(arg, ".onion"))
+		return false;
+	if (arglen != 16 + 6 && arglen != 56 + 6)
+		return false;
+	for (i = 0; i < arglen - 6; i++) {
+		if (arg[i] >= 'a' && arg[i] <= 'z')
+			continue;
+		if (arg[i] >= '0' && arg[i] <= '9')
+			continue;
+		return false;
+	}
+	return true;
+}
+
+/* Rules:
+ *
+ * - not longer than 255
+ * - segments are separated with . dot
+ * - segments do not start or end with - hyphen
+ * - segments must be longer thant zero
+ * - lowercase a-z and digits 0-9 and - hyphen
+ */
+bool is_dnsaddr(const char *arg)
+{
+	size_t i, arglen;
+	int lastdot;
+
+	if (is_ipaddr(arg) || is_toraddr(arg))
+		return false;
+
+	/* now that its not IP or TOR, check its a DNS name */
+	arglen = strlen(arg);
+	if (arglen > 255)
+		return false;
+	lastdot = -1;
+	for (i = 0; i < arglen; i++) {
+		if (arg[i] == '.') {
+			/* segment must be longer than zero */
+			if (i - lastdot == 1)
+				return false;
+			/* last segment can not end with hypen */
+			if (i != 0 && arg[i-1] == '-')
+				return false;
+			lastdot = i;
+			continue;
+		}
+		/* segment cannot start with hyphen */
+		if (i == lastdot + 1 && arg[i] == '-')
+			return false;
+		if (arg[i] >= 'a' && arg[i] <= 'z')
+			continue;
+		if (arg[i] >= '0' && arg[i] <= '9')
+			continue;
+		if (arg[i] == '-')
+			continue;
+		return false;
+	}
+	return true;
+}
+
 struct wireaddr *
 wireaddr_from_hostname(const tal_t *ctx,
 		       const char *hostname,
@@ -714,6 +799,7 @@ struct addrinfo *wireaddr_to_addrinfo(const tal_t *ctx,
 		return ai;
 	case ADDR_TYPE_TOR_V2_REMOVED:
 	case ADDR_TYPE_TOR_V3:
+	case ADDR_TYPE_DNS:
 	case ADDR_TYPE_WEBSOCKET:
 		break;
 	}
@@ -766,6 +852,7 @@ bool all_tor_addresses(const struct wireaddr_internal *wireaddr)
 			switch (wireaddr[i].u.wireaddr.type) {
 			case ADDR_TYPE_IPV4:
 			case ADDR_TYPE_IPV6:
+			case ADDR_TYPE_DNS:
 				return false;
 			case ADDR_TYPE_TOR_V2_REMOVED:
 			case ADDR_TYPE_TOR_V3:

common/wireaddr.h

@@ -37,13 +37,18 @@ struct sockaddr_un;
  *             where `checksum = sha3(".onion checksum" | pubkey || version)[:2]`
  */
 
+/* BOLT-hostnames #7:
+ *   * `5`: DNS hostname; data = `[byte:len][len*byte:hostname][u16:port]` (length up to 258)
+ */
+
 /* BOLT-websockets #7:
  *    * `6`: WebSocket port; data = `[2:port]` (length 2)
  */
 
 #define	TOR_V2_ADDRLEN 10
 #define	TOR_V3_ADDRLEN 35
-#define	LARGEST_ADDRLEN TOR_V3_ADDRLEN
+#define	DNS_ADDRLEN 255
+#define	LARGEST_ADDRLEN DNS_ADDRLEN
 #define	TOR_V3_BLOBLEN 64
 #define	STATIC_TOR_MAGIC_STRING "gen-default-toraddress"
 
@@ -52,10 +57,10 @@ enum wire_addr_type {
 	ADDR_TYPE_IPV6 = 2,
 	ADDR_TYPE_TOR_V2_REMOVED = 3,
 	ADDR_TYPE_TOR_V3 = 4,
-	ADDR_TYPE_WEBSOCKET = 6,
+	ADDR_TYPE_DNS = 5,
+	ADDR_TYPE_WEBSOCKET = 6
 };
 
-/* Structure now fit for tor support */
 struct wireaddr {
 	enum wire_addr_type type;
 	u8 addrlen;
@@ -149,6 +154,16 @@ struct wireaddr_internal {
 
 bool wireaddr_internal_eq(const struct wireaddr_internal *a,
 			  const struct wireaddr_internal *b);
+
+bool separate_address_and_port(const tal_t *ctx, const char *arg,
+			       char **addr, u16 *port);
+
+bool is_ipaddr(const char *arg);
+
+bool is_toraddr(const char *arg);
+
+bool is_dnsaddr(const char *arg);
+
 bool parse_wireaddr_internal(const char *arg, struct wireaddr_internal *addr,
 			     u16 port, bool wildcard_ok, bool dns_ok,
 			     bool unresolved_ok, bool allow_deprecated,

connectd/connectd.c

@@ -874,7 +874,10 @@ static struct io_plan *conn_init(struct io_conn *conn,
 			      "Can't connect to forproxy address");
 		break;
 	case ADDR_INTERNAL_WIREADDR:
+		/* DNS should have been resolved before */
+		assert(addr->u.wireaddr.type != ADDR_TYPE_DNS);
 		/* If it was a Tor address, we wouldn't be here. */
+		assert(!is_toraddr((char*)addr->u.wireaddr.addr));
 		ai = wireaddr_to_addrinfo(tmpctx, &addr->u.wireaddr);
 		break;
 	}
@@ -925,6 +928,14 @@ static void try_connect_one_addr(struct connecting *connect)
 	bool use_proxy = connect->daemon->always_use_proxy;
 	const struct wireaddr_internal *addr = &connect->addrs[connect->addrnum];
 	struct io_conn *conn;
+#if EXPERIMENTAL_FEATURES /* BOLT7 DNS RFC #911 */
+	bool use_dns = connect->daemon->use_dns;
+	struct addrinfo hints, *ais, *aii;
+	struct wireaddr_internal addrhint;
+	int gai_err;
+	struct sockaddr_in *sa4;
+	struct sockaddr_in6 *sa6;
+#endif
 
 	/* In case we fail without a connection, make destroy_io_conn happy */
 	connect->conn = NULL;
@@ -974,6 +985,51 @@ static void try_connect_one_addr(struct connecting *connect)
 		case ADDR_TYPE_IPV6:
 			af = AF_INET6;
 			break;
+		case ADDR_TYPE_DNS:
+#if EXPERIMENTAL_FEATURES /* BOLT7 DNS RFC #911 */
+			if (use_proxy) /* hand it to the proxy */
+				break;
+			if (!use_dns)  /* ignore DNS when we can't use it */
+				goto next;
+			/* Resolve with getaddrinfo */
+			memset(&hints, 0, sizeof(hints));
+			hints.ai_socktype = SOCK_STREAM;
+			hints.ai_family = AF_UNSPEC;
+			hints.ai_protocol = 0;
+			hints.ai_flags = AI_ADDRCONFIG;
+			gai_err = getaddrinfo((char *)addr->u.wireaddr.addr,
+					      tal_fmt(tmpctx, "%d",
+						      addr->u.wireaddr.port),
+					      &hints, &ais);
+			if (gai_err != 0) {
+				status_debug("DNS with getaddrinfo gave: %s",
+					     gai_strerror(gai_err));
+				goto next;
+			}
+			/* create new addrhints on-the-fly per result ... */
+			for (aii = ais; aii; aii = aii->ai_next) {
+				addrhint.itype = ADDR_INTERNAL_WIREADDR;
+				if (aii->ai_family == AF_INET) {
+					sa4 = (struct sockaddr_in *) aii->ai_addr;
+					wireaddr_from_ipv4(&addrhint.u.wireaddr,
+							   &sa4->sin_addr,
+							   addr->u.wireaddr.port);
+				} else if (aii->ai_family == AF_INET6) {
+					sa6 = (struct sockaddr_in6 *) aii->ai_addr;
+					wireaddr_from_ipv6(&addrhint.u.wireaddr,
+							   &sa6->sin6_addr,
+							   addr->u.wireaddr.port);
+				} else {
+					/* skip unsupported ai_family */
+					continue;
+				}
+				tal_arr_expand(&connect->addrs, addrhint);
+				/* don't forget to update convenience pointer */
+				addr = &connect->addrs[connect->addrnum];
+			}
+			freeaddrinfo(ais);
+#endif
+			goto next;
 		case ADDR_TYPE_WEBSOCKET:
 			af = -1;
 			break;
@@ -1158,6 +1214,7 @@ static bool handle_wireaddr_listen(struct daemon *daemon,
 	case ADDR_TYPE_WEBSOCKET:
 	case ADDR_TYPE_TOR_V2_REMOVED:
 	case ADDR_TYPE_TOR_V3:
+	case ADDR_TYPE_DNS:
 		break;
 	}
 	status_failed(STATUS_FAIL_INTERNAL_ERROR,
@@ -1613,6 +1670,10 @@ static void add_seed_addrs(struct wireaddr_internal **addrs,
 		                                   NULL, broken_reply, NULL);
 		if (new_addrs) {
 			for (size_t j = 0; j < tal_count(new_addrs); j++) {
+#if EXPERIMENTAL_FEATURES /* BOLT7 DNS RFC #911 */
+				if (new_addrs[j].type == ADDR_TYPE_DNS)
+					continue;
+#endif
 				struct wireaddr_internal a;
 				a.itype = ADDR_INTERNAL_WIREADDR;
 				a.u.wireaddr = new_addrs[j];

connectd/netaddress.c

@@ -258,6 +258,7 @@ bool guess_address(struct wireaddr *addr)
     }
     case ADDR_TYPE_TOR_V2_REMOVED:
     case ADDR_TYPE_TOR_V3:
+    case ADDR_TYPE_DNS:
     case ADDR_TYPE_WEBSOCKET:
         status_broken("Cannot guess address type %u", addr->type);
         break;

devtools/gossipwith.c

@@ -324,6 +324,9 @@ int main(int argc, char *argv[])
 		case ADDR_TYPE_WEBSOCKET:
 			opt_usage_exit_fail("Don't support websockets");
 			break;
+		case ADDR_TYPE_DNS:
+			opt_usage_exit_fail("Don't support DNS");
+			break;
 		case ADDR_TYPE_IPV4:
 			af = AF_INET;
 			break;