mirror of
https://github.com/nadoo/glider.git
synced 2025-02-23 01:15:41 +08:00
dns: rewrite codes
This commit is contained in:
nadoo
parent
7dc21908d5
commit
d5e3ea539a
6
conf.go
6
conf.go
@ -71,9 +71,9 @@ func confInit() {
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}
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if conf.RulesDir != "" {
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if !path.IsAbs(conf.RulesDir) {
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conf.RulesDir = path.Join(flag.ConfDir(), conf.RulesDir)
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}
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if !path.IsAbs(conf.RulesDir) {
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conf.RulesDir = path.Join(flag.ConfDir(), conf.RulesDir)
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}
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ruleFolderFiles, _ := listDir(conf.RulesDir, ".rule")
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for _, ruleFile := range ruleFolderFiles {
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140
dns/client.go
Normal file
140
dns/client.go
Normal file
@ -0,0 +1,140 @@
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package dns
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import (
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"encoding/binary"
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"io"
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"strings"
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"github.com/nadoo/glider/common/log"
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"github.com/nadoo/glider/proxy"
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)
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// HandleFunc function handles the dns TypeA or TypeAAAA answer
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type HandleFunc func(Domain, ip string) error
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// Client is a dns client struct
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type Client struct {
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dialer proxy.Dialer
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UPServers []string
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UPServerMap map[string][]string
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Handlers []HandleFunc
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tcp bool
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}
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// NewClient returns a new dns client
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func NewClient(dialer proxy.Dialer, upServers ...string) (*Client, error) {
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c := &Client{
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dialer: dialer,
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UPServers: upServers,
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UPServerMap: make(map[string][]string),
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}
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return c, nil
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}
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// Exchange handles request msg and returns response msg
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// reqBytes = reqLen + reqMsg
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func (c *Client) Exchange(reqBytes []byte, clientAddr string) (respBytes []byte, err error) {
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reqMsg := reqBytes[2:]
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reqM := NewMessage()
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err = UnmarshalMessage(reqMsg, reqM)
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if err != nil {
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return
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}
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if reqM.Question.QTYPE == QTypeA || reqM.Question.QTYPE == QTypeAAAA {
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// TODO: if query.QNAME in cache
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// get respMsg from cache
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// set msg id
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// return respMsg, nil
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}
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dnsServer := c.GetServer(reqM.Question.QNAME)
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rc, err := c.dialer.NextDialer(reqM.Question.QNAME+":53").Dial("tcp", dnsServer)
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if err != nil {
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log.F("[dns] failed to connect to server %v: %v", dnsServer, err)
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return
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}
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defer rc.Close()
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if err = binary.Write(rc, binary.BigEndian, reqBytes); err != nil {
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log.F("[dns] failed to write req message: %v", err)
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return
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}
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var respLen uint16
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if err = binary.Read(rc, binary.BigEndian, &respLen); err != nil {
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log.F("[dns] failed to read response length: %v", err)
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return
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}
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respBytes = make([]byte, respLen+2)
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binary.BigEndian.PutUint16(respBytes[:2], respLen)
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respMsg := respBytes[2:]
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_, err = io.ReadFull(rc, respMsg)
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if err != nil {
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log.F("[dns] error in read respMsg %s\n", err)
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return
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}
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if reqM.Question.QTYPE != QTypeA && reqM.Question.QTYPE != QTypeAAAA {
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return
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}
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respM := NewMessage()
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err = UnmarshalMessage(respMsg, respM)
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if err != nil {
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return
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}
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ip := ""
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for _, answer := range respM.Answers {
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if answer.TYPE == QTypeA {
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for _, h := range c.Handlers {
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h(reqM.Question.QNAME, answer.IP)
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}
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if answer.IP != "" {
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ip += answer.IP + ","
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}
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}
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log.F("rr: %+v", answer)
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}
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// add to cache
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log.F("[dns] %s <-> %s, type: %d, %s: %s",
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clientAddr, dnsServer, reqM.Question.QTYPE, reqM.Question.QNAME, ip)
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return
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}
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// SetServer .
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func (c *Client) SetServer(domain string, servers ...string) {
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c.UPServerMap[domain] = append(c.UPServerMap[domain], servers...)
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}
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// GetServer .
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func (c *Client) GetServer(domain string) string {
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domainParts := strings.Split(domain, ".")
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length := len(domainParts)
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for i := length - 2; i >= 0; i-- {
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domain := strings.Join(domainParts[i:length], ".")
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if servers, ok := c.UPServerMap[domain]; ok {
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return servers[0]
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}
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}
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// TODO:
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return c.UPServers[0]
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}
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// AddHandler .
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func (c *Client) AddHandler(h HandleFunc) {
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c.Handlers = append(c.Handlers, h)
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}
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474
dns/dns.go
474
dns/dns.go
@ -1,474 +0,0 @@
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// https://tools.ietf.org/html/rfc1035
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package dns
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import (
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"encoding/binary"
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"errors"
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"io"
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"net"
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"strings"
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"github.com/nadoo/glider/common/log"
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"github.com/nadoo/glider/proxy"
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)
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// HeaderLen is the length of dns msg header
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const HeaderLen = 12
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// UDPMaxLen 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 UDPMaxLen = 512
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// QType .
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const (
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QTypeA = 1 //ipv4
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QTypeAAAA = 28 ///ipv6
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)
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// Msg format
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// https://tools.ietf.org/html/rfc1035#section-4.1
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// All communications inside of the domain protocol are carried in a single
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// format called a message. The top level format of message is divided
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// into 5 sections (some of which are empty in certain cases) shown below:
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//
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// +---------------------+
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// | Header |
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// +---------------------+
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// | Question | the question for the name server
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// +---------------------+
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// | Answer | RRs answering the question
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// +---------------------+
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// | Authority | RRs pointing toward an authority
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// +---------------------+
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// | Additional | RRs holding additional information
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// type Msg struct {
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// Header
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// Questions []Question
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// Answers []RR
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// }
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// Header format
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// https://tools.ietf.org/html/rfc1035#section-4.1.1
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// The header contains the following fields:
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//
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// 1 1 1 1 1 1
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// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | ID |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// |QR| Opcode |AA|TC|RD|RA| Z | RCODE |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | QDCOUNT |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | ANCOUNT |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | NSCOUNT |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | ARCOUNT |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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//
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// type Header struct {
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// ID uint16
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// }
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// Question format
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// https://tools.ietf.org/html/rfc1035#section-4.1.2
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// The question section is used to carry the "question" in most queries,
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// i.e., the parameters that define what is being asked. The section
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// contains QDCOUNT (usually 1) entries, each of the following format:
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//
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// 1 1 1 1 1 1
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// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | |
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// / QNAME /
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// / /
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | QTYPE |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | QCLASS |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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type Question struct {
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QNAME string
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QTYPE uint16
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QCLASS uint16
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Offset int
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}
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// RR format
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// https://tools.ietf.org/html/rfc1035#section-3.2.1
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// https://tools.ietf.org/html/rfc1035#section-4.1.3
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// The answer, authority, and additional sections all share the same
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// format: a variable number of resource records, where the number of
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// records is specified in the corresponding count field in the header.
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// Each resource record has the following format:
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//
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// 1 1 1 1 1 1
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// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | |
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// / /
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// / NAME /
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// | |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | TYPE |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | CLASS |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | TTL |
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// | |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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// | RDLENGTH |
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
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// / RDATA /
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// / /
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// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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type RR struct {
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// NAME string
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TYPE uint16
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CLASS uint16
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TTL uint32
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RDLENGTH uint16
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RDATA []byte
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IP string
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}
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// AnswerHandler function handles the dns TypeA or TypeAAAA answer
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type AnswerHandler func(Domain, ip string) error
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// DNS .
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type DNS struct {
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dialer proxy.Dialer
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addr string
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Tunnel bool
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DNSServer string
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DNSServerMap map[string]string
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AnswerHandlers []AnswerHandler
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}
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// NewDNS returns a dns forwarder. client[dns.udp] -> glider[tcp] -> forwarder[dns.tcp] -> remote dns addr
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func NewDNS(addr, raddr string, dialer proxy.Dialer, tunnel bool) (*DNS, error) {
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s := &DNS{
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dialer: dialer,
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addr: addr,
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Tunnel: tunnel,
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DNSServer: raddr,
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DNSServerMap: make(map[string]string),
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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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go s.ListenAndServeTCP()
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s.ListenAndServeUDP()
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}
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// ListenAndServeUDP .
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func (s *DNS) ListenAndServeUDP() {
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c, err := net.ListenPacket("udp", s.addr)
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if err != nil {
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log.F("[dns] failed to listen on %s, error: %v", s.addr, err)
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return
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}
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defer c.Close()
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log.F("[dns] listening UDP on %s", s.addr)
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for {
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b := make([]byte, UDPMaxLen)
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n, clientAddr, err := c.ReadFrom(b)
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if err != nil {
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log.F("[dns] local read error: %v", err)
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continue
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}
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reqLen := uint16(n)
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// TODO: check here
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if reqLen <= HeaderLen+2 {
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log.F("[dns] not enough data")
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continue
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}
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reqMsg := b[:n]
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go func() {
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_, respMsg, err := s.Exchange(reqLen, reqMsg, clientAddr.String())
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if err != nil {
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log.F("[dns] error in exchange: %s", err)
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return
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}
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_, err = c.WriteTo(respMsg, clientAddr)
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if err != nil {
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log.F("[dns] error in local write: %s", err)
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return
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}
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}()
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}
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}
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// ListenAndServeTCP .
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func (s *DNS) ListenAndServeTCP() {
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l, err := net.Listen("tcp", s.addr)
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if err != nil {
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log.F("[dns]-tcp error: %v", err)
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return
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}
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log.F("[dns]-tcp listening TCP on %s", s.addr)
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for {
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c, err := l.Accept()
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if err != nil {
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log.F("[dns]-tcp error: failed to accept: %v", err)
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continue
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}
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go s.ServeTCP(c)
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}
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}
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// ServeTCP .
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func (s *DNS) ServeTCP(c net.Conn) {
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defer c.Close()
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if c, ok := c.(*net.TCPConn); ok {
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c.SetKeepAlive(true)
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}
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var reqLen uint16
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if err := binary.Read(c, binary.BigEndian, &reqLen); err != nil {
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log.F("[dns]-tcp failed to get request length: %v", err)
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return
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}
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// TODO: check here
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if reqLen <= HeaderLen+2 {
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log.F("[dns]-tcp not enough data")
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return
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}
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reqMsg := make([]byte, reqLen)
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_, err := io.ReadFull(c, reqMsg)
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if err != nil {
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log.F("[dns]-tcp error in read reqMsg %s", err)
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return
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}
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respLen, respMsg, err := s.Exchange(reqLen, reqMsg, c.RemoteAddr().String())
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if err != nil {
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log.F("[dns]-tcp error in exchange: %s", err)
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return
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}
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if err := binary.Write(c, binary.BigEndian, respLen); err != nil {
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log.F("[dns]-tcp error in local write respLen: %s", err)
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return
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}
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if err := binary.Write(c, binary.BigEndian, respMsg); err != nil {
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log.F("[dns]-tcp error in local write respMsg: %s", err)
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return
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}
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}
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// Exchange handles request msg and returns response msg
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// TODO: multiple questions support, parse header to get the number of questions
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func (s *DNS) Exchange(reqLen uint16, reqMsg []byte, addr string) (respLen uint16, respMsg []byte, err error) {
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// fmt.Printf("\ndns req len %d:\n%s\n", reqLen, hex.Dump(reqMsg[:]))
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query, err := parseQuestion(reqMsg)
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if err != nil {
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log.F("[dns] error in parseQuestion reqMsg: %s", err)
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return
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}
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dnsServer := s.GetServer(query.QNAME)
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rc, err := s.dialer.NextDialer(query.QNAME+":53").Dial("tcp", dnsServer)
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if err != nil {
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log.F("[dns] failed to connect to server %v: %v", dnsServer, err)
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return
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}
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defer rc.Close()
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if err = binary.Write(rc, binary.BigEndian, reqLen); err != nil {
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log.F("[dns] failed to write req length: %v", err)
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return
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}
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if err = binary.Write(rc, binary.BigEndian, reqMsg); err != nil {
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log.F("[dns] failed to write req message: %v", err)
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return
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}
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if err = binary.Read(rc, binary.BigEndian, &respLen); err != nil {
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log.F("[dns] failed to read response length: %v", err)
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return
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}
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respMsg = make([]byte, respLen)
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_, err = io.ReadFull(rc, respMsg)
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if err != nil {
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log.F("[dns] error in read respMsg %s\n", err)
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return
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}
|
||||
|
||||
// fmt.Printf("\ndns resp len %d:\n%s\n", respLen, hex.Dump(respMsg[:]))
|
||||
|
||||
var ip string
|
||||
respReq, err := parseQuestion(respMsg)
|
||||
if err != nil {
|
||||
log.F("[dns] error in parseQuestion respMsg: %s", err)
|
||||
return
|
||||
}
|
||||
|
||||
if (respReq.QTYPE == QTypeA || respReq.QTYPE == QTypeAAAA) &&
|
||||
len(respMsg) > respReq.Offset {
|
||||
|
||||
var answers []*RR
|
||||
answers, err = parseAnswers(respMsg[respReq.Offset:])
|
||||
if err != nil {
|
||||
log.F("[dns] error in parseAnswers: %s", err)
|
||||
return
|
||||
}
|
||||
|
||||
for _, answer := range answers {
|
||||
for _, h := range s.AnswerHandlers {
|
||||
h(respReq.QNAME, answer.IP)
|
||||
}
|
||||
|
||||
if answer.IP != "" {
|
||||
ip += answer.IP + ","
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
log.F("[dns] %s <-> %s, type: %d, %s: %s", addr, dnsServer, query.QTYPE, query.QNAME, ip)
|
||||
return
|
||||
}
|
||||
|
||||
// SetServer .
|
||||
func (s *DNS) SetServer(domain, server string) {
|
||||
s.DNSServerMap[domain] = server
|
||||
}
|
||||
|
||||
// GetServer .
|
||||
func (s *DNS) GetServer(domain string) string {
|
||||
if !s.Tunnel {
|
||||
domainParts := strings.Split(domain, ".")
|
||||
length := len(domainParts)
|
||||
for i := length - 2; i >= 0; i-- {
|
||||
domain := strings.Join(domainParts[i:length], ".")
|
||||
|
||||
if server, ok := s.DNSServerMap[domain]; ok {
|
||||
return server
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return s.DNSServer
|
||||
}
|
||||
|
||||
// AddAnswerHandler .
|
||||
func (s *DNS) AddAnswerHandler(h AnswerHandler) {
|
||||
s.AnswerHandlers = append(s.AnswerHandlers, h)
|
||||
}
|
||||
|
||||
func parseQuestion(p []byte) (*Question, error) {
|
||||
q := &Question{}
|
||||
lenP := len(p)
|
||||
|
||||
var i int
|
||||
var domain []byte
|
||||
for i = HeaderLen; i < lenP; {
|
||||
l := int(p[i])
|
||||
|
||||
if l == 0 {
|
||||
i++
|
||||
break
|
||||
}
|
||||
|
||||
if lenP <= i+l+1 {
|
||||
return nil, errors.New("not enough data for QNAME")
|
||||
}
|
||||
|
||||
domain = append(domain, p[i+1:i+l+1]...)
|
||||
domain = append(domain, '.')
|
||||
|
||||
i = i + l + 1
|
||||
}
|
||||
|
||||
if len(domain) == 0 {
|
||||
return nil, errors.New("no QNAME")
|
||||
}
|
||||
|
||||
q.QNAME = string(domain[:len(domain)-1])
|
||||
|
||||
if lenP < i+4 {
|
||||
return nil, errors.New("not enough data")
|
||||
}
|
||||
|
||||
q.QTYPE = binary.BigEndian.Uint16(p[i:])
|
||||
q.QCLASS = binary.BigEndian.Uint16(p[i+2:])
|
||||
q.Offset = i + 4
|
||||
|
||||
return q, nil
|
||||
}
|
||||
|
||||
func parseAnswers(p []byte) ([]*RR, error) {
|
||||
var answers []*RR
|
||||
lenP := len(p)
|
||||
|
||||
for i := 0; i < lenP; {
|
||||
|
||||
// https://tools.ietf.org/html/rfc1035#section-4.1.4
|
||||
// "Message compression",
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | 1 1| OFFSET |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
|
||||
if p[i]>>6 == 3 {
|
||||
i += 2
|
||||
} else {
|
||||
// TODO: none compressed query name and Additional records will be ignored
|
||||
break
|
||||
}
|
||||
|
||||
if lenP <= i+10 {
|
||||
return nil, errors.New("not enough data")
|
||||
}
|
||||
|
||||
answer := &RR{}
|
||||
|
||||
answer.TYPE = binary.BigEndian.Uint16(p[i:])
|
||||
answer.CLASS = binary.BigEndian.Uint16(p[i+2:])
|
||||
answer.TTL = binary.BigEndian.Uint32(p[i+4:])
|
||||
answer.RDLENGTH = binary.BigEndian.Uint16(p[i+8:])
|
||||
answer.RDATA = p[i+10 : i+10+int(answer.RDLENGTH)]
|
||||
|
||||
if answer.TYPE == QTypeA {
|
||||
answer.IP = net.IP(answer.RDATA[:net.IPv4len]).String()
|
||||
} else if answer.TYPE == QTypeAAAA {
|
||||
answer.IP = net.IP(answer.RDATA[:net.IPv6len]).String()
|
||||
}
|
||||
|
||||
answers = append(answers, answer)
|
||||
|
||||
i = i + 10 + int(answer.RDLENGTH)
|
||||
}
|
||||
|
||||
return answers, nil
|
||||
}
|
||||
425
dns/message.go
Normal file
425
dns/message.go
Normal file
@ -0,0 +1,425 @@
|
||||
package dns
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
"encoding/binary"
|
||||
"errors"
|
||||
"fmt"
|
||||
"math/rand"
|
||||
"net"
|
||||
"strings"
|
||||
)
|
||||
|
||||
// UDPMaxLen is the max size of udp dns request.
|
||||
// https://tools.ietf.org/html/rfc1035#section-4.2.1
|
||||
// Messages carried by UDP are restricted to 512 bytes (not counting the IP
|
||||
// or UDP headers). Longer messages are truncated and the TC bit is set in
|
||||
// the header.
|
||||
const UDPMaxLen = 512
|
||||
|
||||
// HeaderLen is the length of dns msg header
|
||||
const HeaderLen = 12
|
||||
|
||||
// QR types
|
||||
const (
|
||||
QRQuery = 0
|
||||
QRResponse = 1
|
||||
)
|
||||
|
||||
// QType .
|
||||
const (
|
||||
QTypeA uint16 = 1 //ipv4
|
||||
QTypeAAAA uint16 = 28 ///ipv6
|
||||
)
|
||||
|
||||
// Message format
|
||||
// https://tools.ietf.org/html/rfc1035#section-4.1
|
||||
// All communications inside of the domain protocol are carried in a single
|
||||
// format called a message. The top level format of message is divided
|
||||
// into 5 sections (some of which are empty in certain cases) shown below:
|
||||
//
|
||||
// +---------------------+
|
||||
// | Header |
|
||||
// +---------------------+
|
||||
// | Question | the question for the name server
|
||||
// +---------------------+
|
||||
// | Answer | RRs answering the question
|
||||
// +---------------------+
|
||||
// | Authority | RRs pointing toward an authority
|
||||
// +---------------------+
|
||||
// | Additional | RRs holding additional information
|
||||
type Message struct {
|
||||
// all dns messages should start with a 12 byte dns header
|
||||
*Header
|
||||
// most dns implementation only support 1 question
|
||||
Question *Question
|
||||
Answers []*RR
|
||||
Authority []*RR
|
||||
Additional []*RR
|
||||
|
||||
// used in UnmarshalMessage
|
||||
unMarshaled []byte
|
||||
}
|
||||
|
||||
// NewMessage returns a new message
|
||||
func NewMessage() *Message {
|
||||
return &Message{
|
||||
Header: &Header{},
|
||||
}
|
||||
}
|
||||
|
||||
// SetQuestion sets a question to dns message,
|
||||
func (m *Message) SetQuestion(q *Question) error {
|
||||
m.Question = q
|
||||
m.Header.SetQdcount(1)
|
||||
return nil
|
||||
}
|
||||
|
||||
// AddAnswer adds an answer to dns message
|
||||
func (m *Message) AddAnswer(rr *RR) error {
|
||||
m.Answers = append(m.Answers, rr)
|
||||
return nil
|
||||
}
|
||||
|
||||
// Marshal marshals message struct to []byte
|
||||
func (m *Message) Marshal() ([]byte, error) {
|
||||
var buf bytes.Buffer
|
||||
|
||||
m.Header.SetQdcount(1)
|
||||
m.Header.SetAncount(len(m.Answers))
|
||||
|
||||
b, err := m.Header.Marshal()
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
buf.Write(b)
|
||||
|
||||
b, err = m.Question.Marshal()
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
buf.Write(b)
|
||||
|
||||
// for _, answer := range m.Answers {
|
||||
// b, err := answer.Marshal()
|
||||
// if err != nil {
|
||||
// return nil, err
|
||||
// }
|
||||
// buf.Write(b)
|
||||
// }
|
||||
|
||||
return buf.Bytes(), nil
|
||||
}
|
||||
|
||||
// UnmarshalMessage unmarshals []bytes to Message
|
||||
func UnmarshalMessage(b []byte, msg *Message) error {
|
||||
msg.unMarshaled = b
|
||||
|
||||
err := UnmarshalHeader(b[:HeaderLen], msg.Header)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
q := &Question{}
|
||||
qLen, err := msg.UnmarshalQuestion(b[HeaderLen:], q)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
msg.SetQuestion(q)
|
||||
|
||||
// resp answers
|
||||
rrLen := 0
|
||||
for i := 0; i < int(msg.Header.ANCOUNT); i++ {
|
||||
rr := &RR{}
|
||||
rrLen, err = msg.UnmarshalRR(HeaderLen+qLen+rrLen, rr)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
msg.AddAnswer(rr)
|
||||
rrLen += rrLen
|
||||
}
|
||||
|
||||
msg.Header.SetAncount(len(msg.Answers))
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// Header format
|
||||
// https://tools.ietf.org/html/rfc1035#section-4.1.1
|
||||
// The header contains the following fields:
|
||||
//
|
||||
// 1 1 1 1 1 1
|
||||
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | ID |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// |QR| Opcode |AA|TC|RD|RA| Z | RCODE |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | QDCOUNT |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | ANCOUNT |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | NSCOUNT |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | ARCOUNT |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
//
|
||||
type Header struct {
|
||||
ID uint16
|
||||
Bits uint16
|
||||
QDCOUNT uint16
|
||||
ANCOUNT uint16
|
||||
NSCOUNT uint16
|
||||
ARCOUNT uint16
|
||||
}
|
||||
|
||||
// NewHeader returns a new dns header
|
||||
func NewHeader(id uint16, qr int) *Header {
|
||||
if id == 0 {
|
||||
id = uint16(rand.Uint32())
|
||||
}
|
||||
|
||||
h := &Header{ID: id}
|
||||
h.SetQR(qr)
|
||||
return h
|
||||
}
|
||||
|
||||
// SetQR .
|
||||
func (h *Header) SetQR(qr int) {
|
||||
h.Bits |= uint16(qr) << 15
|
||||
}
|
||||
|
||||
// SetQdcount sets query count, most dns servers only support 1 query per request
|
||||
func (h *Header) SetQdcount(qdcount int) {
|
||||
h.QDCOUNT = uint16(qdcount)
|
||||
}
|
||||
|
||||
// SetAncount sets answers count
|
||||
func (h *Header) SetAncount(ancount int) {
|
||||
h.ANCOUNT = uint16(ancount)
|
||||
}
|
||||
|
||||
func (h *Header) setFlag(QR uint16, Opcode uint16, AA uint16,
|
||||
TC uint16, RD uint16, RA uint16, RCODE uint16) {
|
||||
h.Bits = QR<<15 + Opcode<<11 + AA<<10 + TC<<9 + RD<<8 + RA<<7 + RCODE
|
||||
}
|
||||
|
||||
// Marshal marshals header struct to []byte
|
||||
func (h *Header) Marshal() ([]byte, error) {
|
||||
var buf bytes.Buffer
|
||||
err := binary.Write(&buf, binary.BigEndian, h)
|
||||
return buf.Bytes(), err
|
||||
}
|
||||
|
||||
// UnmarshalHeader unmarshals []bytes to Header
|
||||
func UnmarshalHeader(b []byte, h *Header) error {
|
||||
if h == nil {
|
||||
return errors.New("unmarshal header must not be nil")
|
||||
}
|
||||
|
||||
if len(b) != HeaderLen {
|
||||
return errors.New("unmarshal header bytes has an unexpected size")
|
||||
}
|
||||
|
||||
h.ID = binary.BigEndian.Uint16(b[:2])
|
||||
h.Bits = binary.BigEndian.Uint16(b[2:4])
|
||||
h.QDCOUNT = binary.BigEndian.Uint16(b[4:6])
|
||||
h.ANCOUNT = binary.BigEndian.Uint16(b[6:8])
|
||||
h.NSCOUNT = binary.BigEndian.Uint16(b[8:10])
|
||||
h.ARCOUNT = binary.BigEndian.Uint16(b[10:])
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// Question format
|
||||
// https://tools.ietf.org/html/rfc1035#section-4.1.2
|
||||
// The question section is used to carry the "question" in most queries,
|
||||
// i.e., the parameters that define what is being asked. The section
|
||||
// contains QDCOUNT (usually 1) entries, each of the following format:
|
||||
//
|
||||
// 1 1 1 1 1 1
|
||||
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | |
|
||||
// / QNAME /
|
||||
// / /
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | QTYPE |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | QCLASS |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
type Question struct {
|
||||
QNAME string
|
||||
QTYPE uint16
|
||||
QCLASS uint16
|
||||
}
|
||||
|
||||
// NewQuestion returns a new dns question
|
||||
func NewQuestion(qtype uint16, domain string) *Question {
|
||||
return &Question{
|
||||
QNAME: domain,
|
||||
QTYPE: qtype,
|
||||
QCLASS: 1,
|
||||
}
|
||||
}
|
||||
|
||||
// Marshal marshals Question struct to []byte
|
||||
func (q *Question) Marshal() ([]byte, error) {
|
||||
var buf bytes.Buffer
|
||||
|
||||
buf.Write(MarshalDomain(q.QNAME))
|
||||
binary.Write(&buf, binary.BigEndian, q.QTYPE)
|
||||
binary.Write(&buf, binary.BigEndian, q.QCLASS)
|
||||
|
||||
return buf.Bytes(), nil
|
||||
}
|
||||
|
||||
// UnmarshalQuestion unmarshals []bytes to Question
|
||||
func (m *Message) UnmarshalQuestion(b []byte, q *Question) (n int, err error) {
|
||||
if q == nil {
|
||||
return 0, errors.New("unmarshal question must not be nil")
|
||||
}
|
||||
|
||||
domain, idx := m.GetDomain(b)
|
||||
q.QNAME = domain
|
||||
q.QTYPE = binary.BigEndian.Uint16(b[idx : idx+2])
|
||||
q.QCLASS = binary.BigEndian.Uint16(b[idx+2 : idx+4])
|
||||
|
||||
return idx + 3 + 1, nil
|
||||
}
|
||||
|
||||
// RR format
|
||||
// https://tools.ietf.org/html/rfc1035#section-3.2.1
|
||||
// https://tools.ietf.org/html/rfc1035#section-4.1.3
|
||||
// The answer, authority, and additional sections all share the same
|
||||
// format: a variable number of resource records, where the number of
|
||||
// records is specified in the corresponding count field in the header.
|
||||
// Each resource record has the following format:
|
||||
//
|
||||
// 1 1 1 1 1 1
|
||||
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | |
|
||||
// / /
|
||||
// / NAME /
|
||||
// | |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | TYPE |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | CLASS |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | TTL |
|
||||
// | |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | RDLENGTH |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
|
||||
// / RDATA /
|
||||
// / /
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
type RR struct {
|
||||
NAME string
|
||||
TYPE uint16
|
||||
CLASS uint16
|
||||
TTL uint32
|
||||
RDLENGTH uint16
|
||||
RDATA []byte
|
||||
|
||||
IP string
|
||||
}
|
||||
|
||||
// NewRR returns a new dns rr
|
||||
func NewRR() *RR {
|
||||
rr := &RR{}
|
||||
return rr
|
||||
}
|
||||
|
||||
// UnmarshalRR unmarshals []bytes to RR
|
||||
func (m *Message) UnmarshalRR(start int, rr *RR) (n int, err error) {
|
||||
if rr == nil {
|
||||
return 0, errors.New("unmarshal question must not be nil")
|
||||
}
|
||||
|
||||
// https://tools.ietf.org/html/rfc1035#section-4.1.4
|
||||
// "Message compression",
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
// | 1 1| OFFSET |
|
||||
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
||||
p := m.unMarshaled[start:]
|
||||
if p[0]>>6 == 3 {
|
||||
offset := binary.BigEndian.Uint16(p[:2])
|
||||
rr.NAME = m.GetDomainByPoint(int(offset) & 0x3F)
|
||||
n += 2
|
||||
} else {
|
||||
// TODO: none compressed query name and Additional records will be ignored
|
||||
return 0, nil
|
||||
}
|
||||
// domain, n := m.GetDomain(p)
|
||||
// rr.NAME = domain
|
||||
|
||||
if len(p) <= n+10 {
|
||||
return 0, errors.New("not enough data")
|
||||
}
|
||||
|
||||
rr.TYPE = binary.BigEndian.Uint16(p[n:])
|
||||
rr.CLASS = binary.BigEndian.Uint16(p[n+2:])
|
||||
rr.TTL = binary.BigEndian.Uint32(p[n+4:])
|
||||
rr.RDLENGTH = binary.BigEndian.Uint16(p[n+8:])
|
||||
rr.RDATA = p[n+10 : n+10+int(rr.RDLENGTH)]
|
||||
|
||||
if rr.TYPE == QTypeA {
|
||||
rr.IP = net.IP(rr.RDATA[:net.IPv4len]).String()
|
||||
} else if rr.TYPE == QTypeAAAA {
|
||||
rr.IP = net.IP(rr.RDATA[:net.IPv6len]).String()
|
||||
}
|
||||
|
||||
n = n + 10 + int(rr.RDLENGTH)
|
||||
|
||||
return n, nil
|
||||
}
|
||||
|
||||
// MarshalDomain marshals domain string struct to []byte
|
||||
func MarshalDomain(domain string) []byte {
|
||||
var buf bytes.Buffer
|
||||
|
||||
for _, seg := range strings.Split(domain, ".") {
|
||||
binary.Write(&buf, binary.BigEndian, byte(len(seg)))
|
||||
binary.Write(&buf, binary.BigEndian, []byte(seg))
|
||||
}
|
||||
binary.Write(&buf, binary.BigEndian, byte(0x00))
|
||||
|
||||
return buf.Bytes()
|
||||
}
|
||||
|
||||
// GetDomain gets domain from bytes
|
||||
func (m *Message) GetDomain(b []byte) (string, int) {
|
||||
var idx, size int
|
||||
var labels = []string{}
|
||||
|
||||
for {
|
||||
if b[idx]&0xC0 == 0xC0 {
|
||||
fmt.Println("aaaaaaaaaaaaaa")
|
||||
offset := binary.BigEndian.Uint16(b[idx : idx+2])
|
||||
lable := m.GetDomainByPoint(int(offset) & 0x3F)
|
||||
labels = append(labels, lable)
|
||||
idx += 2
|
||||
break
|
||||
} else {
|
||||
size = int(b[idx])
|
||||
if size == 0 {
|
||||
idx++
|
||||
break
|
||||
}
|
||||
labels = append(labels, string(b[idx+1:idx+size+1]))
|
||||
idx += (size + 1)
|
||||
}
|
||||
}
|
||||
|
||||
return strings.Join(labels, "."), idx
|
||||
}
|
||||
|
||||
// GetDomainByPoint gets domain from
|
||||
func (m *Message) GetDomainByPoint(offset int) string {
|
||||
domain, _ := m.GetDomain(m.unMarshaled[offset:])
|
||||
return domain
|
||||
}
|
||||
72
dns/server.go
Normal file
72
dns/server.go
Normal file
@ -0,0 +1,72 @@
|
||||
package dns
|
||||
|
||||
import (
|
||||
"encoding/binary"
|
||||
"net"
|
||||
|
||||
"github.com/nadoo/glider/common/log"
|
||||
"github.com/nadoo/glider/proxy"
|
||||
)
|
||||
|
||||
// Server is a dns server struct
|
||||
type Server struct {
|
||||
addr string
|
||||
// Client is used to communicate with upstream dns servers
|
||||
*Client
|
||||
}
|
||||
|
||||
// NewServer returns a new dns server
|
||||
func NewServer(addr string, dialer proxy.Dialer, upServers ...string) (*Server, error) {
|
||||
c, err := NewClient(dialer, upServers...)
|
||||
s := &Server{
|
||||
addr: addr,
|
||||
Client: c,
|
||||
}
|
||||
|
||||
return s, err
|
||||
}
|
||||
|
||||
// ListenAndServe .
|
||||
func (s *Server) ListenAndServe() {
|
||||
c, err := net.ListenPacket("udp", s.addr)
|
||||
if err != nil {
|
||||
log.F("[dns] failed to listen on %s, error: %v", s.addr, err)
|
||||
return
|
||||
}
|
||||
defer c.Close()
|
||||
|
||||
log.F("[dns] listening UDP on %s", s.addr)
|
||||
|
||||
for {
|
||||
reqBytes := make([]byte, 2+UDPMaxLen)
|
||||
n, caddr, err := c.ReadFrom(reqBytes[2:])
|
||||
if err != nil {
|
||||
log.F("[dns] local read error: %v", err)
|
||||
continue
|
||||
}
|
||||
|
||||
reqLen := uint16(n)
|
||||
if reqLen <= HeaderLen+2 {
|
||||
log.F("[dns] not enough message data")
|
||||
continue
|
||||
}
|
||||
|
||||
binary.BigEndian.PutUint16(reqBytes[:2], reqLen)
|
||||
|
||||
go func() {
|
||||
respBytes, err := s.Client.Exchange(reqBytes[:2+n], caddr.String())
|
||||
if err != nil {
|
||||
log.F("[dns] error in exchange: %s", err)
|
||||
return
|
||||
}
|
||||
|
||||
_, err = c.WriteTo(respBytes[2:], caddr)
|
||||
if err != nil {
|
||||
log.F("[dns] error in local write: %s", err)
|
||||
return
|
||||
}
|
||||
|
||||
}()
|
||||
}
|
||||
|
||||
}
|
||||
8
main.go
8
main.go
@ -11,7 +11,7 @@ import (
|
||||
"github.com/nadoo/glider/dns"
|
||||
"github.com/nadoo/glider/proxy"
|
||||
|
||||
_ "github.com/nadoo/glider/proxy/dnstun"
|
||||
// _ "github.com/nadoo/glider/proxy/dnstun"
|
||||
_ "github.com/nadoo/glider/proxy/http"
|
||||
_ "github.com/nadoo/glider/proxy/mixed"
|
||||
_ "github.com/nadoo/glider/proxy/socks5"
|
||||
@ -58,7 +58,7 @@ func main() {
|
||||
dialer := NewRuleDialer(conf.rules, dialerFromConf())
|
||||
ipsetM, _ := NewIPSetManager(conf.IPSet, conf.rules)
|
||||
if conf.DNS != "" {
|
||||
d, err := dns.NewDNS(conf.DNS, conf.DNSServer[0], dialer, false)
|
||||
d, err := dns.NewServer(conf.DNS, dialer, conf.DNSServer...)
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
@ -73,9 +73,9 @@ func main() {
|
||||
}
|
||||
|
||||
// add a handler to update proxy rules when a domain resolved
|
||||
d.AddAnswerHandler(dialer.AddDomainIP)
|
||||
d.AddHandler(dialer.AddDomainIP)
|
||||
if ipsetM != nil {
|
||||
d.AddAnswerHandler(ipsetM.AddDomainIP)
|
||||
d.AddHandler(ipsetM.AddDomainIP)
|
||||
}
|
||||
|
||||
go d.ListenAndServe()
|
||||
|
||||
@ -31,7 +31,6 @@ func (d *direct) Dial(network, addr string) (net.Conn, error) {
|
||||
return c, err
|
||||
}
|
||||
|
||||
// DialUDP connects to the given address via the proxy
|
||||
func (d *direct) DialUDP(network, addr string) (net.PacketConn, net.Addr, error) {
|
||||
pc, err := net.ListenPacket(network, "")
|
||||
if err != nil {
|
||||
|
||||
Loading…
Reference in New Issue
Block a user