mirror of
https://github.com/nadoo/glider.git
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dnstun: add the ability to support both udp and tcp dns request
This commit is contained in:
nadoo
parent
1a14762d84
commit
b29d972adc
124
dns.go
Normal file
124
dns.go
Normal file
@ -0,0 +1,124 @@
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// https://tools.ietf.org/html/rfc1035
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package main
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import (
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"encoding/binary"
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"io/ioutil"
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"net"
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)
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// UDPDNSHeaderLen is the length of UDP dns msg header
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const UDPDNSHeaderLen = 12
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// TCPDNSHEADERLen is the length of TCP dns msg header
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const TCPDNSHEADERLen = 2 + UDPDNSHeaderLen
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// MaxUDPDNSLen is the max size of udp dns request.
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// https://tools.ietf.org/html/rfc1035#section-4.2.1
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// Messages carried by UDP are restricted to 512 bytes (not counting the IP
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// or UDP headers). Longer messages are truncated and the TC bit is set in
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// the header.
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// TODO: If the request length > 512 then the client will send TCP packets instead,
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// so we should also serve tcp requests.
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const MaxUDPDNSLen = 512
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type dns struct {
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*proxy
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raddr string
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}
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// DNSForwarder returns a dns forwarder. client -> dns.udp -> glider -> forwarder -> remote dns addr
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func DNSForwarder(addr, raddr string, upProxy Proxy) (Proxy, error) {
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s := &dns{
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proxy: newProxy(addr, upProxy),
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raddr: raddr,
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}
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return s, nil
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}
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// ListenAndServe .
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func (s *dns) ListenAndServe() {
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l, err := net.ListenPacket("udp", s.addr)
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if err != nil {
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logf("failed to listen on %s: %v", s.addr, err)
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return
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}
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defer l.Close()
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logf("listening UDP on %s", s.addr)
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for {
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data := make([]byte, MaxUDPDNSLen)
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n, clientAddr, err := l.ReadFrom(data)
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if err != nil {
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logf("DNS local read error: %v", err)
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continue
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}
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data = data[:n]
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go func() {
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// TODO: check domain rules and get a proper upstream name server.
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domain := getDomain(data)
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rc, err := s.GetProxy(s.raddr).Dial("tcp", s.raddr)
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if err != nil {
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logf("failed to connect to server %v: %v", s.raddr, err)
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return
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}
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defer rc.Close()
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logf("proxy-dns %s, %s <-> %s", domain, clientAddr.String(), s.raddr)
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// 2 bytes length after tcp header, before dns message
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length := make([]byte, 2)
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binary.BigEndian.PutUint16(length, uint16(len(data)))
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rc.Write(length)
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rc.Write(data)
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resp, err := ioutil.ReadAll(rc)
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if err != nil {
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logf("error in ioutil.ReadAll: %s\n", err)
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return
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}
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// length is not needed in udp dns response. (2 bytes)
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// SEE RFC1035, section 4.2.2 TCP: The message is prefixed with a two byte length field which gives the message length, excluding the two byte length field.
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if len(resp) > 2 {
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msg := resp[2:]
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_, err = l.WriteTo(msg, clientAddr)
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if err != nil {
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logf("error in local write: %s\n", err)
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}
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}
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}()
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}
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}
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// getDomain from dns request playload, return []byte like:
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// []byte{'w', 'w', 'w', '.', 'm', 's', 'n', '.', 'c', 'o', 'm', '.'}
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// []byte("www.msn.com.")
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func getDomain(p []byte) []byte {
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var ret []byte
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for i := UDPDNSHeaderLen; i < len(p); {
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l := int(p[i])
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if l == 0 {
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break
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}
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ret = append(ret, p[i+1:i+l+1]...)
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ret = append(ret, '.')
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i = i + l + 1
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}
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// TODO: check here
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// domain name could not be null, so the length of ret always >= 1?
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return ret[:len(ret)-1]
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}
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113
dnstun.go
113
dnstun.go
@ -2,123 +2,34 @@
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package main
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import (
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"encoding/binary"
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"io/ioutil"
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"net"
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)
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// UDPDNSHeaderLen is the length of UDP dns msg header
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const UDPDNSHeaderLen = 12
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// TCPDNSHEADERLen is the length of TCP dns msg header
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const TCPDNSHEADERLen = 2 + UDPDNSHeaderLen
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// MaxUDPDNSLen is the max size of udp dns request.
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// https://tools.ietf.org/html/rfc1035#section-4.2.1
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// Messages carried by UDP are restricted to 512 bytes (not counting the IP
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// or UDP headers). Longer messages are truncated and the TC bit is set in
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// the header.
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// TODO: If the request length > 512 then the client will send TCP packets instead,
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// so we should also serve tcp requests.
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const MaxUDPDNSLen = 512
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type dnstun struct {
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*proxy
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raddr string
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udp Proxy
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tcp Proxy
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}
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// DNSTunProxy returns a dns forwarder. client -> dns.udp -> glider -> forwarder -> remote dns addr
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func DNSTunProxy(addr, raddr string, upProxy Proxy) (Proxy, error) {
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// DNSTun returns a dns forwarder. client -> dns.udp -> glider -> forwarder -> remote dns addr
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func DNSTun(addr, raddr string, upProxy Proxy) (Proxy, error) {
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s := &dnstun{
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proxy: newProxy(addr, upProxy),
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raddr: raddr,
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}
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s.udp, _ = DNSForwarder(addr, raddr, upProxy)
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s.tcp, _ = TCPTun(addr, raddr, upProxy)
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return s, nil
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}
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// ListenAndServe .
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func (s *dnstun) ListenAndServe() {
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l, err := net.ListenPacket("udp", s.addr)
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if err != nil {
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logf("failed to listen on %s: %v", s.addr, err)
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return
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if s.udp != nil {
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go s.udp.ListenAndServe()
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}
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defer l.Close()
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logf("listening UDP on %s", s.addr)
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for {
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data := make([]byte, MaxUDPDNSLen)
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n, clientAddr, err := l.ReadFrom(data)
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if err != nil {
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logf("DNS local read error: %v", err)
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continue
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}
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data = data[:n]
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go func() {
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// TODO: check domain rules and get a proper upstream name server.
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domain := getDomain(data)
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rc, err := s.GetProxy(s.raddr).Dial("tcp", s.raddr)
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if err != nil {
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logf("failed to connect to server %v: %v", s.raddr, err)
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return
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}
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defer rc.Close()
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logf("proxy-dnstun %s, %s <-> %s", domain, clientAddr.String(), s.raddr)
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// 2 bytes length after tcp header, before dns message
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length := make([]byte, 2)
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binary.BigEndian.PutUint16(length, uint16(len(data)))
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rc.Write(length)
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rc.Write(data)
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resp, err := ioutil.ReadAll(rc)
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if err != nil {
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logf("error in ioutil.ReadAll: %s\n", err)
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return
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}
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// length is not needed in udp dns response. (2 bytes)
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// SEE RFC1035, section 4.2.2 TCP: The message is prefixed with a two byte length field which gives the message length, excluding the two byte length field.
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if len(resp) > 2 {
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msg := resp[2:]
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_, err = l.WriteTo(msg, clientAddr)
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if err != nil {
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logf("error in local write: %s\n", err)
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}
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}
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}()
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if s.tcp != nil {
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s.tcp.ListenAndServe()
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}
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}
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// getDomain from dns request playload, return []byte like:
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// []byte{'w', 'w', 'w', '.', 'm', 's', 'n', '.', 'c', 'o', 'm', '.'}
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// []byte("www.msn.com.")
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func getDomain(p []byte) []byte {
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var ret []byte
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for i := UDPDNSHeaderLen; i < len(p); {
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l := int(p[i])
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if l == 0 {
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break
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}
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ret = append(ret, p[i+1:i+l+1]...)
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ret = append(ret, '.')
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i = i + l + 1
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}
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// TODO: check here
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// domain name could not be null, so the length of ret always >= 1?
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return ret[:len(ret)-1]
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}
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16
proxy.go
16
proxy.go
@ -90,23 +90,23 @@ func ProxyFromURL(s string, forwarder Proxy) (Proxy, error) {
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}
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switch u.Scheme {
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case "mixed":
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return MixedProxy("tcp", addr, user, pass, forwarder)
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case "http":
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return HTTPProxy(addr, forwarder)
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case "socks5":
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return SOCKS5Proxy("tcp", addr, user, pass, forwarder)
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case "ss":
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p, err := SSProxy(addr, user, pass, forwarder)
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return p, err
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case "socks5":
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return SOCKS5Proxy("tcp", addr, user, pass, forwarder)
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case "redir":
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return RedirProxy(addr, forwarder)
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case "tcptun":
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d := strings.Split(addr, "=")
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return TCPTunProxy(d[0], d[1], forwarder)
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return TCPTun(d[0], d[1], forwarder)
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case "dnstun":
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d := strings.Split(addr, "=")
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return DNSTunProxy(d[0], d[1], forwarder)
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case "http":
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return HTTPProxy(addr, forwarder)
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case "mixed":
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return MixedProxy("tcp", addr, user, pass, forwarder)
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return DNSTun(d[0], d[1], forwarder)
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}
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return nil, errors.New("unknown schema '" + u.Scheme + "'")
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@ -7,8 +7,8 @@ type tcptun struct {
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raddr string
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}
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// TCPTunProxy returns a redirect proxy.
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func TCPTunProxy(addr, raddr string, upProxy Proxy) (Proxy, error) {
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// TCPTun returns a redirect proxy.
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func TCPTun(addr, raddr string, upProxy Proxy) (Proxy, error) {
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s := &tcptun{
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proxy: newProxy(addr, upProxy),
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raddr: raddr,
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