Merge pull request #33 from cxz66666/add-custom-dns

feat: support custom dns config

README.md

@@ -226,6 +226,8 @@ $ docker compose up -d
 
 + `udp-port-forwarding`: UDP 端口转发，格式为 `本地地址-远程地址,本地地址-远程地址,...`，例如 `127.0.0.1:53-10.10.0.21:53`。多个转发用 `,` 分隔
 
++ `custom-dns`: 指定自定义DNS解析结果，格式为 `域名:IP,域名:IP,...`，例如 `www.cc98.org:10.10.98.98,appservice.zju.edu.cn:10.203.8.198`。多个解析用 `,` 分隔:
+
 + `twf-id`: twfID 登录，调试用途，一般不需要加此参数
 
 + `config`: 指定配置文件，内容参考 `config.toml.example`。启用配置文件时其他参数无效

config.toml.example

@@ -23,4 +23,9 @@ port_forwarding = [
  { network_type = "tcp", bind_address = "127.0.0.1:9898", remote_address = "10.10.98.98:80" },
  { network_type = "tcp", bind_address = "127.0.0.1:9899", remote_address = "10.10.98.98:80" },
  { network_type = "udp", bind_address = "127.0.0.1:1053", remote_address = "10.10.0.21:53" }
+]
+
+custom_dns = [
+ { host_name = "appservice.zju.edu.cn", ip = "10.203.8.198"},
+ { host_name = "www.cc98.org", ip = "10.10.98.98"}
 ]

core/EasyConnectClient.go

@@ -21,6 +21,11 @@ type Forwarding struct {
  RemoteAddress string
 }
 
+type CustomDNS struct {
+ HostName string
+ IP string
+}
+
 var SocksBind string
 var SocksUser string
 var SocksPasswd string
@@ -35,6 +40,7 @@ var ProxyAll bool
 var ForwardingList []Forwarding
 var EnableKeepAlive bool
 var ZjuDnsServer string
+var CustomDNSList []CustomDNS
 
 type EasyConnectClient struct {
  queryConn net.Conn
@@ -140,6 +146,15 @@ func StartClient(host string, port int, username string, password string, twfId
  go client.ServeForwarding(strings.ToLower(singleForwarding.NetworkType), singleForwarding.BindAddress, singleForwarding.RemoteAddress)
  }
 
+ for _, customDNS := range CustomDNSList {
+ ipAddr := net.ParseIP(customDNS.IP)
+ if ipAddr == nil {
+ log.Printf("Custom DNS for host_name %s is invalid, SKIP", customDNS.HostName)
+ }
+ SetPermantDns(customDNS.HostName, ipAddr)
+ log.Printf("Custom DNS %s -> %s\n", customDNS.HostName, customDNS.IP)
+ }
+
  if EnableKeepAlive {
  go client.ServeSocks5(SocksBind, ZjuDnsServer)
  client.KeepAlive(ZjuDnsServer)

core/dns_cache.go

@@ -47,3 +47,15 @@ func SetDnsCache(host string, ip net.IP) {
  }
  dnsCaches.cache.Set(host, ip, cache.DefaultExpiration)
 }
+
+func SetPermantDns(host string, ip net.IP) {
+ once.Do(func() {
+ dnsCaches = &DnsCache{
+ cache: cache.New(time.Duration(DnsTTL)*time.Second, time.Duration(DnsTTL)*2*time.Second),
+ }
+ })
+ if DebugDump {
+ log.Printf("SetPermantDnsCache: %s -> %s", host, ip.String())
+ }
+ dnsCaches.cache.Set(host, ip, cache.NoExpiration)
+}

main.go

@@ -30,13 +30,19 @@ type (
  ZjuDnsServer *string `toml:"zju_dns_server"`
  DebugDump *bool `toml:"debug_dump"`
  PortForwarding []SinglePortForwarding `toml:"port_forwarding"`
+ CustomDns []SingleCustomDns `toml:"custom_dns"`
  }
 
  SinglePortForwarding struct {
  NetworkType *string `toml:"network_type"`
  BindAddress *string `toml:"bind_address"`
  RemoteAddress *string `toml:"remote_address"`
  }
+
+ SingleCustomDns struct {
+ HostName *string `toml:"host_name"`
+ IP *string `toml:"ip"`
+ }
 )
 
 func getTomlVal[T int | uint64 | string | bool](valPointer *T, defaultVal T) T {
@@ -51,7 +57,7 @@ func main() {
  // CLI args
  host, port, username, password := "", 0, "", ""
  disableServerConfig, disableZjuConfig, disableZjuDns, disableMultiLine, disableKeepAlive := false, false, false, false, false
- twfId, configFile, tcpPortForwarding, udpPortForwarding := "", "", "", ""
+ twfId, configFile, tcpPortForwarding, udpPortForwarding, customDns := "", "", "", "", ""
 
  flag.StringVar(&host, "server", "rvpn.zju.edu.cn", "EasyConnect server address")
  flag.IntVar(&port, "port", 443, "EasyConnect port address")
@@ -70,6 +76,7 @@ func main() {
  flag.BoolVar(&core.DebugDump, "debug-dump", false, "Enable traffic debug dump (only for debug usage)")
  flag.StringVar(&tcpPortForwarding, "tcp-port-forwarding", "", "TCP port forwarding (e.g. 0.0.0.0:9898-10.10.98.98:80,127.0.0.1:9899-10.10.98.98:80)")
  flag.StringVar(&udpPortForwarding, "udp-port-forwarding", "", "UDP port forwarding (e.g. 127.0.0.1:53-10.10.0.21:53)")
+ flag.StringVar(&customDns, "custom-dns", "", "Custom set dns lookup (e.g. www.cc98.org:10.10.98.98,appservice.zju.edu.cn:10.203.8.198)")
  flag.BoolVar(&disableKeepAlive, "disable-keep-alive", false, "Disable keep alive")
  flag.StringVar(&core.ZjuDnsServer, "zju-dns-server", "10.10.0.21", "ZJU DNS server address")
  flag.StringVar(&twfId, "twf-id", "", "Login using twfID captured (mostly for debug usage)")
@@ -140,6 +147,23 @@ func main() {
  })
  }
 
+ for _, singleCustomDns := range conf.CustomDns {
+ if singleCustomDns.HostName == nil {
+ fmt.Println("ZJU Connect: host_name is not set")
+ return
+ }
+
+ if singleCustomDns.IP == nil {
+ fmt.Println("ZJU Connect: IP is not set")
+ return
+ }
+
+ core.CustomDNSList = append(core.CustomDNSList, core.CustomDNS{
+ HostName: *singleCustomDns.HostName,
+ IP: *singleCustomDns.IP,
+ })
+ }
+
  if host == "" || (username == "" || password == "") {
  fmt.Println("ZJU Connect: host, username and password can not be empty")
  return
@@ -185,6 +209,22 @@ func main() {
  }
  }
 
+ if customDns != "" {
+ customDnsList := strings.Split(customDns, ",")
+ for _, singleCustomDns := range customDnsList {
+ singleCustomDnsSplit := strings.Split(singleCustomDns, ":")
+ if len(singleCustomDnsSplit) != 2 {
+ fmt.Println("ZJU Connect: wrong custom dns format")
+ return
+ }
+
+ core.CustomDNSList = append(core.CustomDNSList, core.CustomDNS{
+ HostName: singleCustomDnsSplit[0],
+ IP: singleCustomDnsSplit[1],
+ })
+ }
+ }
+
  if host == "" || ((username == "" || password == "") && twfId == "") {
  fmt.Println("ZJU Connect")
  fmt.Println("Please see: https://github.com/mythologyli/zju-connect")