feature: support marking packet on upstream server

ReadMe.md

@@ -584,10 +584,10 @@ entware|ipkg update<br>ipkg install smartdns|软件源路径：https://bin.entwa
 | audit-size | 审计大小 | 128K | 数字 + K、M 或 G | audit-size 128K |
 | audit-num | 审计归档个数 | 2 | 大于等于 0 的数字 | audit-num 2 |
 | conf-file | 附加配置文件 | 无 | 合法路径字符串 | conf-file /etc/smartdns/smartdns.more.conf |
-| server | 上游 UDP DNS | 无 | 可重复。<br>[ip][:port]：服务器 IP:端口（可选）<br>[-blacklist-ip]：配置 IP 过滤结果。<br>[-whitelist-ip]：指定仅接受参数中配置的 IP 范围<br>[-group [group] ...]：DNS 服务器所属组，比如 office 和 foreign，和 nameserver 配套使用<br>[-exclude-default-group]：将 DNS 服务器从默认组中排除 | server 8.8.8.8:53 -blacklist-ip -group g1 |
-| server-tcp | 上游 TCP DNS | 无 | 可重复。<br>[ip][:port]：服务器 IP:端口（可选）<br>[-blacklist-ip]：配置 IP 过滤结果<br>[-whitelist-ip]：指定仅接受参数中配置的 IP 范围。<br>[-group [group] ...]：DNS 服务器所属组，比如 office 和 foreign，和 nameserver 配套使用<br>[-exclude-default-group]：将 DNS 服务器从默认组中排除  | server-tcp 8.8.8.8:53 |
-| server-tls | 上游 TLS DNS | 无 | 可重复。<br>[ip][:port]：服务器 IP:端口（可选)<br>[-spki-pin [sha256-pin]]：TLS 合法性校验 SPKI 值，base64 编码的 sha256 SPKI pin 值<br>[-host-name]：TLS SNI 名称, 名称设置为-，表示停用SNI名称<br>[-tls-host-verify]：TLS 证书主机名校验<br> [-no-check-certificate]：跳过证书校验<br>[-blacklist-ip]：配置 IP 过滤结果<br>[-whitelist-ip]：仅接受参数中配置的 IP 范围<br>[-group [group] ...]：DNS 服务器所属组，比如 office 和 foreign，和 nameserver 配套使用<br>[-exclude-default-group]：将 DNS 服务器从默认组中排除 | server-tls 8.8.8.8:853 |
-| server-https | 上游 HTTPS DNS | 无 | 可重复。<br>https://[host][:port]/path：服务器 IP:端口（可选）<br>[-spki-pin [sha256-pin]]：TLS 合法性校验 SPKI 值，base64 编码的 sha256 SPKI pin 值<br>[-host-name]：TLS SNI 名称<br>[-http-host]：http 协议头主机名<br>[-tls-host-verify]：TLS 证书主机名校验<br> [-no-check-certificate]：跳过证书校验<br>[-blacklist-ip]：配置 IP 过滤结果<br>[-whitelist-ip]：仅接受参数中配置的 IP 范围。<br>[-group [group] ...]：DNS 服务器所属组，比如 office 和 foreign，和 nameserver 配套使用<br>[-exclude-default-group]：将 DNS 服务器从默认组中排除 | server-https https://cloudflare-dns.com/dns-query |
+| server | 上游 UDP DNS | 无 | 可重复。<br>[ip][:port]：服务器 IP:端口（可选）<br>[-blacklist-ip]：配置 IP 过滤结果。<br>[-whitelist-ip]：指定仅接受参数中配置的 IP 范围<br>[-group [group] ...]：DNS 服务器所属组，比如 office 和 foreign，和 nameserver 配套使用<br>[-exclude-default-group]：将 DNS 服务器从默认组中排除。<br>[-set-mark]：设置数据包标记so-mark| server 8.8.8.8:53 -blacklist-ip -group g1 |
+| server-tcp | 上游 TCP DNS | 无 | 可重复。<br>[ip][:port]：服务器 IP:端口（可选）<br>[-blacklist-ip]：配置 IP 过滤结果<br>[-whitelist-ip]：指定仅接受参数中配置的 IP 范围。<br>[-group [group] ...]：DNS 服务器所属组，比如 office 和 foreign，和 nameserver 配套使用<br>[-exclude-default-group]：将 DNS 服务器从默认组中排除。<br>[-set-mark]：设置数据包标记so-mark | server-tcp 8.8.8.8:53 |
+| server-tls | 上游 TLS DNS | 无 | 可重复。<br>[ip][:port]：服务器 IP:端口（可选)<br>[-spki-pin [sha256-pin]]：TLS 合法性校验 SPKI 值，base64 编码的 sha256 SPKI pin 值<br>[-host-name]：TLS SNI 名称, 名称设置为-，表示停用SNI名称<br>[-tls-host-verify]：TLS 证书主机名校验<br> [-no-check-certificate]：跳过证书校验<br>[-blacklist-ip]：配置 IP 过滤结果<br>[-whitelist-ip]：仅接受参数中配置的 IP 范围<br>[-group [group] ...]：DNS 服务器所属组，比如 office 和 foreign，和 nameserver 配套使用<br>[-exclude-default-group]：将 DNS 服务器从默认组中排除。<br>[-set-mark]：设置数据包标记so-mark | server-tls 8.8.8.8:853 |
+| server-https | 上游 HTTPS DNS | 无 | 可重复。<br>https://[host][:port]/path：服务器 IP:端口（可选）<br>[-spki-pin [sha256-pin]]：TLS 合法性校验 SPKI 值，base64 编码的 sha256 SPKI pin 值<br>[-host-name]：TLS SNI 名称<br>[-http-host]：http 协议头主机名<br>[-tls-host-verify]：TLS 证书主机名校验<br> [-no-check-certificate]：跳过证书校验<br>[-blacklist-ip]：配置 IP 过滤结果<br>[-whitelist-ip]：仅接受参数中配置的 IP 范围。<br>[-group [group] ...]：DNS 服务器所属组，比如 office 和 foreign，和 nameserver 配套使用<br>[-exclude-default-group]：将 DNS 服务器从默认组中排除。<br>[-set-mark]：设置数据包标记so-mark | server-https https://cloudflare-dns.com/dns-query |
 | speed-check-mode | 测速模式选择 | 无 | [ping\|tcp:[80]\|none] | speed-check-mode ping,tcp:80,tcp:443 |
 | response-mode | 首次查询响应模式 | first-ping |模式：[fisrt-ping\|fastest-ip\|fastest-response]<br> [first-ping]: 最快ping响应地址模式，DNS上游最快查询时延+ping时延最短，查询等待与链接体验最佳;<br>[fastest-ip]: 最快IP地址模式，查询到的所有IP地址中ping最短的IP。需等待IP测速; <br>[fastest-response]: 最快响应的DNS结果，DNS查询等待时间最短，返回的IP地址可能不是最快。| response-mode first-ping |
 | address | 指定域名 IP 地址 | 无 | address /domain/[ip\|-\|-4\|-6\|#\|#4\|#6] <br>- 表示忽略 <br># 表示返回 SOA <br>4 表示 IPv4 <br>6 表示 IPv6 | address /www.example.com/1.2.3.4 |

ReadMe_en.md

@@ -118,6 +118,9 @@ From the comparison, smartdns found the fastest IP address to visit www.baidu.co
 8. **High performance, low resource consumption**  
    Multi-threaded asynchronous IO mode, cache cache query results.
 
+9. **DNS domain forwarding**
+   Support DNS forwarding, ipset and nftables.
+
 ## Architecture
 
 ![Architecture](doc/architecture.png)
@@ -543,10 +546,10 @@ Note: Merlin firmware is derived from ASUS firmware and can theoretically be use
 |audit-size|audit log size|128K|number+K,M,G|audit-size 128K
 |audit-num|archived audit log number|2|Integer, 0 means turn off the log|audit-num 2
 |conf-file|additional conf file|None|File path|conf-file /etc/smartdns/smartdns.more.conf
-|server|Upstream UDP DNS server|None|Repeatable <br>`[ip][:port]`: Server IP, port optional. <br>`[-blacklist-ip]`: The "-blacklist-ip" parameter is to filtering IPs which is configured by "blacklist-ip". <br>`[-whitelist-ip]`: whitelist-ip parameter specifies that only the IP range configured in whitelist-ip is accepted. <br>`[-group [group] ...]`: The group to which the DNS server belongs, such as office, foreign, use with nameserver. <br>`[-exclude-default-group]`: Exclude DNS servers from the default group| server 8.8.8.8:53 -blacklist-ip
-|server-tcp|Upstream TCP DNS server|None|Repeatable <br>`[ip][:port]`: Server IP, port optional. <br>`[-blacklist-ip]`: The "-blacklist-ip" parameter is to filtering IPs which is configured by "blacklist-ip". <br>`[-whitelist-ip]`: whitelist-ip parameter specifies that only the IP range configured in whitelist-ip is accepted. <br>`[-group [group] ...]`: The group to which the DNS server belongs, such as office, foreign, use with nameserver. <br>`[-exclude-default-group]`: Exclude DNS servers from the default group| server-tcp 8.8.8.8:53
-|server-tls|Upstream TLS DNS server|None|Repeatable <br>`[ip][:port]`: Server IP, port optional. <br>`[-spki-pin [sha256-pin]]`: TLS verify SPKI value, a base64 encoded SHA256 hash<br>`[-host-name]`:TLS Server name. `-` to disable SNI name.<br>`[-tls-host-verify]`: TLS cert hostname to verify. <br>`-no-check-certificate:`: No check certificate. <br>`[-blacklist-ip]`: The "-blacklist-ip" parameter is to filtering IPs which is configured by "blacklist-ip". <br>`[-whitelist-ip]`: whitelist-ip parameter specifies that only the IP range configured in whitelist-ip is accepted. <br>`[-group [group] ...]`: The group to which the DNS server belongs, such as office, foreign, use with nameserver. <br>`[-exclude-default-group]`: Exclude DNS servers from the default group| server-tls 8.8.8.8:853
-|server-https|Upstream HTTPS DNS server|None|Repeatable <br>`https://[host][:port]/path`: Server IP, port optional. <br>`[-spki-pin [sha256-pin]]`: TLS verify SPKI value, a base64 encoded SHA256 hash<br>`[-host-name]`:TLS Server name<br>`[-http-host]`：http header host. <br>`[-tls-host-verify]`: TLS cert hostname to verify. <br>`-no-check-certificate:`: No check certificate. <br>`[-blacklist-ip]`: The "-blacklist-ip" parameter is to filtering IPs which is configured by "blacklist-ip". <br>`[-whitelist-ip]`: whitelist-ip parameter specifies that only the IP range configured in whitelist-ip is accepted. <br>`[-group [group] ...]`: The group to which the DNS server belongs, such as office, foreign, use with nameserver. <br>`[-exclude-default-group]`: Exclude DNS servers from the default group| server-https https://cloudflare-dns.com/dns-query
+|server|Upstream UDP DNS server|None|Repeatable <br>`[ip][:port]`: Server IP, port optional. <br>`[-blacklist-ip]`: The "-blacklist-ip" parameter is to filtering IPs which is configured by "blacklist-ip". <br>`[-whitelist-ip]`: whitelist-ip parameter specifies that only the IP range configured in whitelist-ip is accepted. <br>`[-group [group] ...]`: The group to which the DNS server belongs, such as office, foreign, use with nameserver. <br>`[-exclude-default-group]`: Exclude DNS servers from the default group. <br>`[-set-mark]`：set mark on packets | server 8.8.8.8:53 -blacklist-ip
+|server-tcp|Upstream TCP DNS server|None|Repeatable <br>`[ip][:port]`: Server IP, port optional. <br>`[-blacklist-ip]`: The "-blacklist-ip" parameter is to filtering IPs which is configured by "blacklist-ip". <br>`[-whitelist-ip]`: whitelist-ip parameter specifies that only the IP range configured in whitelist-ip is accepted. <br>`[-group [group] ...]`: The group to which the DNS server belongs, such as office, foreign, use with nameserver. <br>`[-exclude-default-group]`: Exclude DNS servers from the default group <br>`[-set-mark]`：set mark on packets | server-tcp 8.8.8.8:53
+|server-tls|Upstream TLS DNS server|None|Repeatable <br>`[ip][:port]`: Server IP, port optional. <br>`[-spki-pin [sha256-pin]]`: TLS verify SPKI value, a base64 encoded SHA256 hash<br>`[-host-name]`:TLS Server name. `-` to disable SNI name.<br>`[-tls-host-verify]`: TLS cert hostname to verify. <br>`-no-check-certificate:`: No check certificate. <br>`[-blacklist-ip]`: The "-blacklist-ip" parameter is to filtering IPs which is configured by "blacklist-ip". <br>`[-whitelist-ip]`: whitelist-ip parameter specifies that only the IP range configured in whitelist-ip is accepted. <br>`[-group [group] ...]`: The group to which the DNS server belongs, such as office, foreign, use with nameserver. <br>`[-exclude-default-group]`: Exclude DNS servers from the default group <br> `[-set-mark]`：set mark on packets | server-tls 8.8.8.8:853
+|server-https|Upstream HTTPS DNS server|None|Repeatable <br>`https://[host][:port]/path`: Server IP, port optional. <br>`[-spki-pin [sha256-pin]]`: TLS verify SPKI value, a base64 encoded SHA256 hash<br>`[-host-name]`:TLS Server name<br>`[-http-host]`：http header host. <br>`[-tls-host-verify]`: TLS cert hostname to verify. <br>`-no-check-certificate:`: No check certificate. <br>`[-blacklist-ip]`: The "-blacklist-ip" parameter is to filtering IPs which is configured by "blacklist-ip". <br>`[-whitelist-ip]`: whitelist-ip parameter specifies that only the IP range configured in whitelist-ip is accepted. <br>`[-group [group] ...]`: The group to which the DNS server belongs, such as office, foreign, use with nameserver. <br>`[-exclude-default-group]`: Exclude DNS servers from the default group <br> `[-set-mark]`：set mark on packets | server-https https://cloudflare-dns.com/dns-query
 |speed-check-mode|Speed ​​mode|None|[ping\|tcp:[80]\|none]|speed-check-mode ping,tcp:80,tcp:443
 |response-mode|First query response mode|first-ping|Mode: [fisrt-ping\|fastest-ip\|fastest-response]<br> [first-ping]: The fastest dns + ping response mode, DNS query delay + ping delay is the shortest;<br>[fastest-ip]: The fastest IP address mode, return the fastest ip address, may take some time to test speed. <br>[fastest-response]: The fastest response DNS result mode, the DNS query waiting time is the shortest. | response-mode first-ping |
 |address|Domain IP address|None|address /domain/[ip\|-\|-4\|-6\|#\|#4\|#6], `-` for ignore, `#` for return SOA, `4` for IPV4, `6` for IPV6| address /www.example.com/1.2.3.4

etc/smartdns/smartdns.conf

@@ -32,6 +32,7 @@
 #   -no-rule-soa: Skip address SOA(#) rules.
 #   -no-dualstack-selection: Disable dualstack ip selection.
 #   -force-aaaa-soa: force AAAA query return SOA.
+#   -set-mark: set mark on packets.
 # example: 
 #  IPV4: 
 #    bind :53

package/luci-compat/files/luci/i18n/smartdns.zh-cn.po

@@ -230,6 +230,12 @@ msgstr "下载的文件列表。"
 msgid "Local Port"
 msgstr "本地端口"
 
+msgid "Marking Packets"
+msgstr "数据包标记"
+
+msgid "Set mark on packets."
+msgstr "设置数据包标记。"
+
 msgid "Maximum TTL for all domain result."
 msgstr "所有域名的最大 TTL 值。"
 

package/luci-compat/files/luci/model/cbi/smartdns/upstream.lua

@@ -127,6 +127,12 @@ o.rempty      = true
 o:depends("type", "tls")
 o:depends("type", "https")
 
+---- mark
+o = s:option(Value, "set_mark", translate("Marking Packets"), translate("Set mark on packets."))
+o.default     = ""
+o.rempty      = true
+o.datatype    = "uinteger"
+
 ---- other args
 o = s:option(Value, "addition_arg", translate("Additional Server Args"), translate("Additional Args for upstream dns servers"))
 o.default     = ""

package/luci/files/luci/i18n/smartdns.zh-cn.po

@@ -256,6 +256,12 @@ msgstr "下载文件列表"
 msgid "Local Port"
 msgstr "本地端口"
 
+msgid "Marking Packets"
+msgstr "数据包标记"
+
+msgid "Set mark on packets."
+msgstr "设置数据包标记。"
+
 msgid "Maximum TTL for all domain result."
 msgstr "所有域名的最大 TTL 值。"
 

package/luci/files/root/www/luci-static/resources/view/smartdns/smartdns.js

@@ -584,6 +584,14 @@ return view.extend({
 		o.depends("type", "tls")
 		o.depends("type", "https")
 
+		// mark
+		o = s.taboption("advanced", form.Value, "set_mark", _("Marking Packets"),
+			_("Set mark on packets."))
+		o.default = ""
+		o.rempty = true
+		o.datatype = "uinteger"
+		o.modalonly = true;
+		
 		// other args
 		o = s.taboption("advanced", form.Value, "addition_arg", _("Additional Server Args"),
 			_("Additional Args for upstream dns servers"))

package/openwrt/files/etc/init.d/smartdns

@@ -183,6 +183,7 @@ load_server()
 	config_get check_edns "$section" "check_edns" "0"
 	config_get spki_pin "$section" "spki_pin" ""
 	config_get addition_arg "$section" "addition_arg" ""
+	config_get set_mark "$section" "set_mark" ""
 
 	[ "$enabled" = "0" ] && return
 
@@ -214,6 +215,7 @@ load_server()
 	[ "$blacklist_ip" = "0" ] || ADDITIONAL_ARGS="$ADDITIONAL_ARGS -blacklist-ip"
 	[ "$check_edns" = "0" ] || ADDITIONAL_ARGS="$ADDITIONAL_ARGS -check-edns"
 	[ -z "$spki_pin" ] || ADDITIONAL_ARGS="$ADDITIONAL_ARGS -spki-pin $spki_pin"
+	[ -z "$set_mark" ] || ADDITIONAL_ARGS="$ADDITIONAL_ARGS -set-mark $set_mark"
 
 	if [ -z "$port" ]; then
 		DNS_ADDRESS="$ip"

src/dns_client.c

@@ -93,6 +93,7 @@ struct dns_server_info {
 	int port;
 	/* server type */
 	dns_server_type_t type;
+	long long so_mark;
 
 	/* client socket */
 	int fd;
@@ -1045,6 +1046,7 @@ static int _dns_client_server_add(char *server_ip, char *server_host, int port,
 	server_info->ttl_range = 0;
 	server_info->skip_check_cert = skip_check_cert;
 	server_info->prohibit = 0;
+	server_info->so_mark = flags->set_mark;
 	pthread_mutex_init(&server_info->lock, NULL);
 	memcpy(&server_info->flags, flags, sizeof(server_info->flags));
 
@@ -1694,6 +1696,13 @@ static int _dns_client_create_socket_udp(struct dns_server_info *server_info)
 		return -1;
 	}
 
+	if (server_info->so_mark >= 0) {
+		unsigned int so_mark = server_info->so_mark;
+		if (setsockopt(fd, SOL_SOCKET, SO_MARK, &so_mark, sizeof(so_mark)) != 0) {
+			tlog(TLOG_DEBUG, "set socket mark failed, %s", strerror(errno));
+		}
+	}
+
 	setsockopt(server_info->fd, IPPROTO_IP, IP_RECVTTL, &on, sizeof(on));
 	setsockopt(server_info->fd, SOL_IP, IP_TTL, &val, sizeof(val));
 	setsockopt(server_info->fd, SOL_SOCKET, SO_PRIORITY, &priority, sizeof(priority));
@@ -1736,6 +1745,13 @@ static int _DNS_client_create_socket_tcp(struct dns_server_info *server_info)
 		goto errout;
 	}
 
+	if (server_info->so_mark >= 0) {
+		unsigned int so_mark = server_info->so_mark;
+		if (setsockopt(fd, SOL_SOCKET, SO_MARK, &so_mark, sizeof(so_mark)) != 0) {
+			tlog(TLOG_DEBUG, "set socket mark failed, %s", strerror(errno));
+		}
+	}
+
 	/* enable tcp fast open */
 	if (setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN_CONNECT, &yes, sizeof(yes)) != 0) {
 		tlog(TLOG_DEBUG, "enable TCP fast open failed, %s", strerror(errno));
@@ -1818,6 +1834,13 @@ static int _DNS_client_create_socket_tls(struct dns_server_info *server_info, ch
 		goto errout;
 	}
 
+	if (server_info->so_mark >= 0) {
+		unsigned int so_mark = server_info->so_mark;
+		if (setsockopt(fd, SOL_SOCKET, SO_MARK, &so_mark, sizeof(so_mark)) != 0) {
+			tlog(TLOG_DEBUG, "set socket mark failed, %s", strerror(errno));
+		}
+	}
+
 	if (setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN_CONNECT, &yes, sizeof(yes)) != 0) {
 		tlog(TLOG_DEBUG, "enable TCP fast open failed.");
 	}

src/dns_client.h

@@ -111,6 +111,7 @@ struct client_dns_server_flags {
 	dns_server_type_t type;
 	unsigned int server_flag;
 	unsigned int result_flag;
+	long long set_mark;
 
 	union {
 		struct client_dns_server_flag_udp udp;

src/dns_conf.c

@@ -370,6 +370,7 @@ static int _config_server(int argc, char *argv[], dns_server_type_t type, int de
 		{"tls-host-verify", required_argument, NULL, 'V' }, /* verify tls hostname */
 		{"group", required_argument, NULL, 'g'}, /* add to group */
 		{"exclude-default-group", no_argument, NULL, 'E'}, /* ecluse this from default group */
+		{"set-mark", required_argument, NULL, 254}, /* set mark */
 		{NULL, no_argument, NULL, 0}
 	};
 	/* clang-format on */
@@ -390,6 +391,7 @@ static int _config_server(int argc, char *argv[], dns_server_type_t type, int de
 	server->hostname[0] = '\0';
 	server->httphost[0] = '\0';
 	server->tls_host_verify[0] = '\0';
+	server->set_mark = -1;
 
 	if (type == DNS_SERVER_HTTPS) {
 		if (parse_uri(ip, NULL, server->server, &port, server->path) != 0) {
@@ -467,6 +469,10 @@ static int _config_server(int argc, char *argv[], dns_server_type_t type, int de
 			server->skip_check_cert = 1;
 			break;
 		}
+		case 254: {
+			server->set_mark = atoll(optarg);
+			break;
+		}
 		default:
 			break;
 		}
@@ -533,7 +539,7 @@ static void _config_address_destroy(radix_node_t *node, void *cbctx)
 	node->data = NULL;
 }
 
-static int _config_domain_set_rule_add_ext(char *set_name, enum domain_rule type, void *rule, unsigned int flags,
+static int _config_domain_set_rule_add_ext(const char *set_name, enum domain_rule type, void *rule, unsigned int flags,
 										   int is_clear_flag)
 {
 	struct dns_domain_set_rule *set_rule = NULL;
@@ -587,7 +593,7 @@ errout:
 	return -1;
 }
 
-static int _config_domian_set_rule_flags(char *set_name, unsigned int flags, int is_clear_flag)
+static int _config_domian_set_rule_flags(const char *set_name, unsigned int flags, int is_clear_flag)
 {
 	return _config_domain_set_rule_add_ext(set_name, DOMAIN_RULE_FLAGS, NULL, flags, is_clear_flag);
 }
@@ -664,7 +670,7 @@ errout:
 	return -1;
 }
 
-static int _config_domain_rule_flag_set(char *domain, unsigned int flag, unsigned int is_clear)
+static int _config_domain_rule_flag_set(const char *domain, unsigned int flag, unsigned int is_clear)
 {
 	struct dns_domain_rule *domain_rule = NULL;
 	struct dns_domain_rule *old_domain_rule = NULL;

src/dns_conf.h

@@ -231,6 +231,7 @@ struct dns_servers {
 	unsigned int server_flag;
 	int ttl;
 	dns_server_type_t type;
+	long long set_mark;
 	char skip_check_cert;
 	char spki[DNS_MAX_SPKI_LEN];
 	char hostname[DNS_MAX_CNAME_LEN];

src/smartdns.c

@@ -269,6 +269,7 @@ static int _smartdns_add_servers(void)
 		flags.type = dns_conf_servers[i].type;
 		flags.server_flag = dns_conf_servers[i].server_flag;
 		flags.result_flag = dns_conf_servers[i].result_flag;
+		flags.set_mark = dns_conf_servers[i].set_mark;
 		ret = dns_client_add_server(dns_conf_servers[i].server, dns_conf_servers[i].port, dns_conf_servers[i].type,
 									&flags);
 		if (ret != 0) {