server: support bind to device

ReadMe.md

@@ -567,8 +567,8 @@ entware|ipkg update<br>ipkg install smartdns|软件源路径：https://bin.entwa
 | 键名 | 功能说明 | 默认值 | 可用值/要求 | 举例 |
 | :--- | :--- | :--- | :--- | :--- |
 | server-name | DNS 服务器名称 | 操作系统主机名 / smartdns | 符合主机名规格的字符串 | server-name smartdns |
-| bind | DNS 监听端口号  | [::]:53 | 可绑定多个端口。<br>IP:PORT: 服务器 IP:端口号<br>[-group]: 请求时使用的 DNS 服务器组<br>[-no-rule-addr]：跳过 address 规则<br>[-no-rule-nameserver]：跳过 Nameserver 规则<br>[-no-rule-ipset]：跳过 ipset 和 nftset 规则<br>[-no-rule-soa]：跳过 SOA(#) 规则<br>[-no-dualstack-selection]：停用双栈测速<br>[-no-speed-check]：停用测速<br>[-no-cache]：停止缓存 | bind :53 |
-| bind-tcp | DNS TCP 监听端口号 | [::]:53 | 可绑定多个端口。<br>IP:PORT: 服务器 IP:端口号<br>[-group]: 请求时使用的 DNS 服务器组<br>[-no-rule-addr]：跳过 address 规则<br>[-no-rule-nameserver]：跳过 nameserver 规则<br>[-no-rule-ipset]：跳过 ipset 和 nftset 规则。<br>[-no-rule-soa]：跳过 SOA(#) 规则<br>[-no-dualstack-selection]：停用双栈测速<br>[-no-speed-check]：停用测速<br>[-no-cache]：停止缓存 | bind-tcp :53 |
+| bind | DNS 监听端口号  | [::]:53 | 可绑定多个端口。<br>IP:PORT@DEVICE: 服务器 IP:端口号@设备名<br>[-group]: 请求时使用的 DNS 服务器组<br>[-no-rule-addr]：跳过 address 规则<br>[-no-rule-nameserver]：跳过 Nameserver 规则<br>[-no-rule-ipset]：跳过 ipset 和 nftset 规则<br>[-no-rule-soa]：跳过 SOA(#) 规则<br>[-no-dualstack-selection]：停用双栈测速<br>[-no-speed-check]：停用测速<br>[-no-cache]：停止缓存 | bind :53@eth0 |
+| bind-tcp | DNS TCP 监听端口号 | [::]:53 | 可绑定多个端口。<br>IP:PORT@DEVICE: 服务器 IP:端口号@设备名<br>[-group]: 请求时使用的 DNS 服务器组<br>[-no-rule-addr]：跳过 address 规则<br>[-no-rule-nameserver]：跳过 nameserver 规则<br>[-no-rule-ipset]：跳过 ipset 和 nftset 规则。<br>[-no-rule-soa]：跳过 SOA(#) 规则<br>[-no-dualstack-selection]：停用双栈测速<br>[-no-speed-check]：停用测速<br>[-no-cache]：停止缓存 | bind-tcp :53 |
 | cache-size | 域名结果缓存个数 | 512 | 大于等于 0 的数字 | cache-size 512 |
 | cache-persist | 是否持久化缓存 | 自动。<br>当 cache-file 所在的位置有超过 128 MB 的可用空间时启用，否则禁用。 | [yes\|no] | cache-persist yes |
 | cache-file | 缓存持久化文件路径 | /tmp/smartdns.cache | 合法路径字符串 | cache-file /tmp/smartdns.cache |

ReadMe_en.md

@@ -529,8 +529,8 @@ Note: Merlin firmware is derived from ASUS firmware and can theoretically be use
 |parameter|Parameter function|Default value|Value type|Example|
 |--|--|--|--|--|
 |server-name|DNS name|host name/smartdns|any string like hosname|server-name smartdns
-|bind|DNS listening port number|[::]:53|Support binding multiple ports<br>`IP:PORT`: server IP, port number. <br>`[-group]`: The DNS server group used when requesting. <br>`[-no-rule-addr]`: Skip the address rule. <br>`[-no-rule-nameserver]`: Skip the Nameserver rule. <br>`[-no-rule-ipset]`: Skip the Ipset or nftset rules. <br>`[-no-rule-soa]`: Skip address SOA(#) rules.<br>`[-no-dualstack-selection]`: Disable dualstack ip selection.<br>`[-no-speed-check]`: Disable speed measurement. <br>`[-no-cache]`: stop caching |bind :53
-|bind-tcp|TCP mode DNS listening port number|[::]:53|Support binding multiple ports<br>`IP:PORT`: server IP, port number. <br>`[-group]`: The DNS server group used when requesting. <br>`[-no-rule-addr]`: Skip the address rule. <br>`[-no-rule-nameserver]`: Skip the Nameserver rule. <br>`[-no-rule-ipset]`: Skip the Ipset or nftset rules. <br>`[-no-rule-soa]`: Skip address SOA(#) rules.<br>`[-no-dualstack-selection]`: Disable dualstack ip selection.<br>`[-no-speed-check]`: Disable speed measurement. <br>`[-no-cache]`: stop caching |bind-tcp :53
+|bind|DNS listening port number|[::]:53|Support binding multiple ports<br>`IP:PORT@DEVICE`: server IP, port number, and device. <br>`[-group]`: The DNS server group used when requesting. <br>`[-no-rule-addr]`: Skip the address rule. <br>`[-no-rule-nameserver]`: Skip the Nameserver rule. <br>`[-no-rule-ipset]`: Skip the Ipset or nftset rules. <br>`[-no-rule-soa]`: Skip address SOA(#) rules.<br>`[-no-dualstack-selection]`: Disable dualstack ip selection.<br>`[-no-speed-check]`: Disable speed measurement. <br>`[-no-cache]`: stop caching |bind :53@eth0
+|bind-tcp|TCP mode DNS listening port number|[::]:53|Support binding multiple ports<br>`IP:PORT@DEVICE`: server IP, port number and device. <br>`[-group]`: The DNS server group used when requesting. <br>`[-no-rule-addr]`: Skip the address rule. <br>`[-no-rule-nameserver]`: Skip the Nameserver rule. <br>`[-no-rule-ipset]`: Skip the Ipset or nftset rules. <br>`[-no-rule-soa]`: Skip address SOA(#) rules.<br>`[-no-dualstack-selection]`: Disable dualstack ip selection.<br>`[-no-speed-check]`: Disable speed measurement. <br>`[-no-cache]`: stop caching |bind-tcp :53
 |cache-size|Domain name result cache number|512|integer|cache-size 512
 |cache-persist|enable persist cache|Auto: Enabled if the location of `cache-file` has more than 128MB of free space.|[yes\|no]|cache-persist yes
 |cache-file|cache persist file|/tmp/smartdns.cache|路径|cache-file /tmp/smartdns.cache

etc/smartdns/smartdns.conf

@@ -19,9 +19,9 @@
 
 # dns server bind ip and port, default dns server port is 53, support binding multi ip and port
 # bind udp server
-#   bind [IP]:[port] [-group [group]] [-no-rule-addr] [-no-rule-nameserver] [-no-rule-ipset] [-no-speed-check] [-no-cache] [-no-rule-soa] [-no-dualstack-selection]
+#   bind [IP]:[port][@device] [-group [group]] [-no-rule-addr] [-no-rule-nameserver] [-no-rule-ipset] [-no-speed-check] [-no-cache] [-no-rule-soa] [-no-dualstack-selection]
 # bind tcp server
-#   bind-tcp [IP]:[port] [-group [group]] [-no-rule-addr] [-no-rule-nameserver] [-no-rule-ipset] [-no-speed-check] [-no-cache] [-no-rule-soa] [-no-dualstack-selection]
+#   bind-tcp [IP]:[port][@device] [-group [group]] [-no-rule-addr] [-no-rule-nameserver] [-no-rule-ipset] [-no-speed-check] [-no-cache] [-no-rule-soa] [-no-dualstack-selection]
 # option:
 #   -group: set domain request to use the appropriate server group.
 #   -no-rule-addr: skip address rule.
@@ -36,9 +36,11 @@
 # example: 
 #  IPV4: 
 #    bind :53
+#    bind :53@eth0
 #    bind :6053 -group office -no-speed-check
 #  IPV6:
 #    bind [::]:53
+#    bind [::]:53@eth0
 #    bind-tcp [::]:53
 bind [::]:53
 

src/dns_server.c

@@ -34,6 +34,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <ifaddrs.h>
+#include <net/if.h>
 #include <netinet/ip.h>
 #include <netinet/tcp.h>
 #include <pthread.h>
@@ -42,6 +43,7 @@
 #include <string.h>
 #include <sys/epoll.h>
 #include <sys/eventfd.h>
+#include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 
@@ -5333,14 +5335,19 @@ static int _dns_create_socket(const char *host_ip, int type)
 	struct addrinfo *gai = NULL;
 	char port_str[8];
 	char ip[MAX_IP_LEN];
+	char host_ip_device[MAX_IP_LEN * 2];
 	int port = 0;
 	char *host = NULL;
 	int optval = 1;
 	int yes = 1;
 	const int priority = SOCKET_PRIORITY;
 	const int ip_tos = SOCKET_IP_TOS;
+	const char *ifname = NULL;
 
-	if (parse_ip(host_ip, ip, &port) == 0) {
+	safe_strncpy(host_ip_device, host_ip, sizeof(host_ip_device));
+	ifname = strstr(host_ip_device, "@");
+
+	if (parse_ip(host_ip_device, ip, &port) == 0) {
 		host = ip;
 	}
 
@@ -5375,6 +5382,17 @@ static int _dns_create_socket(const char *host_ip, int type)
 	setsockopt(fd, SOL_SOCKET, SO_PRIORITY, &priority, sizeof(priority));
 	setsockopt(fd, IPPROTO_IP, IP_TOS, &ip_tos, sizeof(ip_tos));
 
+	if (ifname != NULL) {
+		struct ifreq ifr;
+		memset(&ifr, 0, sizeof(struct ifreq));
+		safe_strncpy(ifr.ifr_name, ifname + 1, sizeof(ifr.ifr_name));
+		ioctl(fd, SIOCGIFINDEX, &ifr);
+		if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(struct ifreq)) < 0) {
+			tlog(TLOG_ERROR, "bind socket to device %s faild, %s\n", ifr.ifr_name, strerror(errno));
+			goto errout;
+		}
+	}
+
 	if (bind(fd, gai->ai_addr, gai->ai_addrlen) != 0) {
 		tlog(TLOG_ERROR, "bind service %s failed, %s\n", host_ip, strerror(errno));
 		goto errout;