feature: add option srv-record support SRV.

etc/smartdns/smartdns.conf

@@ -265,6 +265,11 @@ log-level info
 # specific cname to domain
 # cname /domain/target
 
+# add srv record, support multiple srv record.
+# srv-record /domain/[target][,port][,priority][,weight]
+# srv-record /_ldap._tcp.example.com/ldapserver.example.com,389
+# srv-record /_ldap._tcp.example.com/
+
 # enalbe DNS64 feature
 # dns64 [ip/subnet]
 # dns64 64:ff9b::/96

src/dns_conf.c

@@ -66,6 +66,9 @@ int dns_hosts_record_num;
 /* DNS64 */
 struct dns_dns64 dns_conf_dns_dns64;
 
+/* SRV-HOST */
+struct dns_srv_record_table dns_conf_srv_record_table;
+
 /* server ip/port  */
 struct dns_bind_ip dns_conf_bind_ip[DNS_MAX_BIND_IP];
 int dns_conf_bind_ip_num = 0;
@@ -505,6 +508,26 @@ static void _config_proxy_table_destroy(void)
 	}
 }
 
+static void _config_srv_record_table_destroy(void)
+{
+	struct dns_srv_records *srv_records = NULL;
+	struct dns_srv_record *srv_record, *tmp1 = NULL;
+	struct hlist_node *tmp = NULL;
+	unsigned int i;
+
+	hash_for_each_safe(dns_conf_srv_record_table.srv, i, tmp, srv_records, node)
+	{
+		list_for_each_entry_safe(srv_record, tmp1, &srv_records->list, list)
+		{
+			list_del(&srv_record->list);
+			free(srv_record);
+		}
+
+		hlist_del_init(&srv_records->node);
+		free(srv_records);
+	}
+}
+
 static int _config_server(int argc, char *argv[], dns_server_type_t type, int default_port)
 {
 	int index = dns_conf_server_num;
@@ -1860,6 +1883,122 @@ static int _config_cname(void *data, int argc, char *argv[])
 	return 0;
 }
 
+struct dns_srv_records *dns_server_get_srv_record(const char *domain)
+{
+	uint32_t key = 0;
+
+	key = hash_string(domain);
+	struct dns_srv_records *srv_records = NULL;
+	hash_for_each_possible(dns_conf_srv_record_table.srv, srv_records, node, key)
+	{
+		if (strncmp(srv_records->domain, domain, DNS_MAX_CONF_CNAME_LEN) == 0) {
+			return srv_records;
+		}
+	}
+
+	return NULL;
+}
+
+static int _confg_srv_record_add(const char *domain, const char *host, unsigned short priority, unsigned short weight,
+							   unsigned short port)
+{
+	struct dns_srv_records *srv_records = NULL;
+	struct dns_srv_record *srv_record = NULL;
+	uint32_t key = 0;
+
+	srv_records = dns_server_get_srv_record(domain);
+	if (srv_records == NULL) {
+		srv_records = malloc(sizeof(*srv_records));
+		if (srv_records == NULL) {
+			goto errout;
+		}
+		memset(srv_records, 0, sizeof(*srv_records));
+		safe_strncpy(srv_records->domain, domain, DNS_MAX_CONF_CNAME_LEN);
+		INIT_LIST_HEAD(&srv_records->list);
+		key = hash_string(domain);
+		hash_add(dns_conf_srv_record_table.srv, &srv_records->node, key);
+	}
+
+	srv_record = malloc(sizeof(*srv_record));
+	if (srv_record == NULL) {
+		goto errout;
+	}
+	memset(srv_record, 0, sizeof(*srv_record));
+	safe_strncpy(srv_record->host, host, DNS_MAX_CONF_CNAME_LEN);
+	srv_record->priority = priority;
+	srv_record->weight = weight;
+	srv_record->port = port;
+	list_add_tail(&srv_record->list, &srv_records->list);
+
+	return 0;
+errout:
+	if (srv_record != NULL) {
+		free(srv_record);
+	}
+	return -1;
+}
+
+static int _config_srv_record(void *data, int argc, char *argv[])
+{
+	char *value = NULL;
+	char domain[DNS_MAX_CONF_CNAME_LEN];
+	char buff[DNS_MAX_CONF_CNAME_LEN];
+	char *ptr = NULL;
+	int ret = -1;
+
+	char *host_s;
+	char *priority_s;
+	char *weight_s;
+	char *port_s;
+
+	unsigned short priority = 0;
+	unsigned short weight = 0;
+	unsigned short port = 1;
+
+	if (argc < 2) {
+		goto errout;
+	}
+
+	value = argv[1];
+	if (_get_domain(value, domain, DNS_MAX_CONF_CNAME_LEN, &value) != 0) {
+		goto errout;
+	}
+
+	safe_strncpy(buff, value, sizeof(buff));
+
+	host_s = strtok_r(buff, ",", &ptr);
+	if (host_s == NULL) {
+		host_s = "";
+		goto out;
+	}
+
+	port_s = strtok_r(NULL, ",", &ptr);
+	if (port_s != NULL) {
+		port = atoi(port_s);
+	}
+
+	priority_s = strtok_r(NULL, ",", &ptr);
+	if (priority_s != NULL) {
+		priority = atoi(priority_s);
+	}
+
+	weight_s = strtok_r(NULL, ",", &ptr);
+	if (weight_s != NULL) {
+		weight = atoi(weight_s);
+	}
+out:
+	ret = _confg_srv_record_add(domain, host_s, priority, weight, port);
+	if (ret != 0) {
+		goto errout;
+	}
+
+	return 0;
+
+errout:
+	tlog(TLOG_ERROR, "add srv-record %s:%s failed", domain, value);
+	return -1;
+}
+
 static void _config_speed_check_mode_clear(struct dns_domain_check_orders *check_orders)
 {
 	memset(check_orders->orders, 0, sizeof(check_orders->orders));
@@ -4154,6 +4293,7 @@ static struct config_item _config_item[] = {
 	CONF_YESNO("expand-ptr-from-address", &dns_conf_expand_ptr_from_address),
 	CONF_CUSTOM("address", _config_address, NULL),
 	CONF_CUSTOM("cname", _config_cname, NULL),
+	CONF_CUSTOM("srv-record", _config_srv_record, NULL),
 	CONF_CUSTOM("proxy-server", _config_proxy_server, NULL),
 	CONF_YESNO("ipset-timeout", &dns_conf_ipset_timeout_enable),
 	CONF_CUSTOM("ipset", _config_ipset, NULL),
@@ -4406,6 +4546,7 @@ static int _dns_server_load_conf_init(void)
 	hash_init(dns_ptr_table.ptr);
 	hash_init(dns_domain_set_name_table.names);
 	hash_init(dns_ip_set_name_table.names);
+	hash_init(dns_conf_srv_record_table.srv);
 
 	return 0;
 }
@@ -4456,6 +4597,7 @@ void dns_server_load_exit(void)
 	_config_host_table_destroy(0);
 	_config_qtype_soa_table_destroy();
 	_config_proxy_table_destroy();
+	_config_srv_record_table_destroy();
 
 	dns_conf_server_num = 0;
 	dns_server_bind_destroy();

src/dns_conf.h

@@ -488,6 +488,25 @@ struct dns_dns64 {
 	uint32_t prefix_len;
 };
 
+struct dns_srv_record {
+	struct list_head list;
+	char host[DNS_MAX_CNAME_LEN];
+	unsigned short priority;
+	unsigned short weight;
+	unsigned short port;
+};
+
+struct dns_srv_records {
+	char domain[DNS_MAX_CNAME_LEN];
+	struct hlist_node node;
+	struct list_head list;
+};
+
+struct dns_srv_record_table {
+	DECLARE_HASHTABLE(srv, 4);
+};
+extern struct dns_srv_record_table dns_conf_srv_record_table;
+
 extern struct dns_dns64 dns_conf_dns_dns64;
 
 extern struct dns_bind_ip dns_conf_bind_ip[DNS_MAX_BIND_IP];
@@ -584,6 +603,8 @@ int dns_server_check_update_hosts(void);
 
 struct dns_proxy_names *dns_server_get_proxy_nams(const char *proxyname);
 
+struct dns_srv_records *dns_server_get_srv_record(const char *domain);
+
 extern int config_additional_file(void *data, int argc, char *argv[]);
 
 const char *dns_conf_get_cache_dir(void);

src/dns_server.c

@@ -276,6 +276,8 @@ struct dns_request {
 	int has_soa;
 	int force_soa;
 
+	struct dns_srv_records *srv_records;
+
 	atomic_t notified;
 	atomic_t do_callback;
 	atomic_t adblock;
@@ -949,6 +951,29 @@ static void _dns_server_setup_soa(struct dns_request *request)
 	soa->minimum = 86400;
 }
 
+static int _dns_server_add_srv(struct dns_server_post_context *context)
+{
+	struct dns_request *request = context->request;
+	struct dns_srv_records *srv_records = request->srv_records;
+	struct dns_srv_record *srv_record = NULL;
+	int ret = 0;
+
+	if (srv_records == NULL) {
+		return 0;
+	}
+
+	list_for_each_entry(srv_record, &srv_records->list, list)
+	{
+		ret = dns_add_SRV(context->packet, DNS_RRS_AN, request->domain, request->ip_ttl, srv_record->priority,
+						  srv_record->weight, srv_record->port, srv_record->host);
+		if (ret != 0) {
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
 static int _dns_add_rrs(struct dns_server_post_context *context)
 {
 	struct dns_request *request = context->request;
@@ -1011,6 +1036,10 @@ static int _dns_add_rrs(struct dns_server_post_context *context)
 		ret |= dns_add_OPT_ECS(context->packet, &request->ecs);
 	}
 
+	if (request->srv_records != NULL) {
+		ret |= _dns_server_add_srv(context);
+	}
+
 	if (request->rcode != DNS_RC_NOERROR) {
 		tlog(TLOG_INFO, "result: %s, qtype: %d, rtcode: %d, id: %d", domain, context->qtype, request->rcode,
 			 request->id);
@@ -4159,6 +4188,28 @@ static int _dns_server_process_DDR(struct dns_request *request)
 }
 
 static int _dns_server_process_srv(struct dns_request *request)
+{
+	struct dns_srv_records *srv_records = dns_server_get_srv_record(request->domain);
+	if (srv_records == NULL) {
+		return -1;
+	}
+
+	request->rcode = DNS_RC_NOERROR;
+	request->ip_ttl = _dns_server_get_local_ttl(request);
+	request->srv_records = srv_records;
+
+	struct dns_server_post_context context;
+	_dns_server_post_context_init(&context, request);
+	context.do_audit = 1;
+	context.do_reply = 1;
+	context.do_cache = 0;
+	context.do_force_soa = 0;
+	_dns_request_post(&context);
+
+	return 0;
+}
+
+static int _dns_server_process_svcb(struct dns_request *request)
 {
 	if (strncmp("_dns.resolver.arpa", request->domain, DNS_MAX_CNAME_LEN) == 0) {
 		return _dns_server_process_DDR(request);
@@ -5268,7 +5319,7 @@ static int _dns_server_process_special_query(struct dns_request *request)
 	switch (request->qtype) {
 	case DNS_T_PTR:
 		break;
-	case DNS_T_SVCB:
+	case DNS_T_SRV:
 		ret = _dns_server_process_srv(request);
 		if (ret == 0) {
 			goto clean_exit;
@@ -5277,6 +5328,15 @@ static int _dns_server_process_special_query(struct dns_request *request)
 			request->passthrough = 1;
 		}
 		break;
+	case DNS_T_SVCB:
+		ret = _dns_server_process_svcb(request);
+		if (ret == 0) {
+			goto clean_exit;
+		} else {
+			/* pass to upstream server */
+			request->passthrough = 1;
+		}
+		break;
 	case DNS_T_A:
 		break;
 	case DNS_T_AAAA:

src/smartdns.c

@@ -1112,7 +1112,7 @@ int main(int argc, char *argv[])
 errout:
 	if (is_run_as_daemon) {
 		daemon_kickoff(ret, dns_conf_log_console | verbose_screen);
-	} else {
+	} else if (dns_conf_log_console == 0 && verbose_screen == 0) {
 		_smartdns_print_error_tip();
 	}
 	smartdns_test_notify(2);