Adding support for DOH (json web api + RFC8484)

doh/doh_client.go

@@ -0,0 +1,130 @@
+package doh
+
+import (
+	"bytes"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/miekg/dns"
+	"github.com/projectdiscovery/retryablehttp-go"
+)
+
+type Client struct {
+	DefaultResolver Resolver
+	httpClient      *retryablehttp.Client
+}
+
+func NewWithOptions(options Options) *Client {
+	return &Client{DefaultResolver: options.DefaultResolver, httpClient: options.httpClient}
+}
+
+func New() *Client {
+	return NewWithOptions(Options{DefaultResolver: Cloudflare, httpClient: retryablehttp.NewClient(retryablehttp.DefaultOptionsSingle)})
+}
+
+func (c *Client) Query(name string, question QuestionType) (*Response, error) {
+	return c.QueryWithResolver(c.DefaultResolver, name, question)
+}
+
+func (c *Client) QueryWithResolver(r Resolver, name string, question QuestionType) (*Response, error) {
+	return c.QueryWithJsonAPI(r, name, question)
+}
+
+func (c *Client) QueryWithJsonAPI(r Resolver, name string, question QuestionType) (*Response, error) {
+	req, err := retryablehttp.NewRequest(http.MethodGet, r.URL, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Accept", "application/dns-json")
+	q := req.URL.Query()
+	q.Add("name", name)
+	q.Add("type", question.ToString())
+	req.URL.RawQuery = q.Encode()
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.Body == nil {
+		return nil, errors.New("empty response body")
+	}
+
+	var response Response
+
+	err = json.NewDecoder(resp.Body).Decode(&response)
+	if err != nil {
+		return nil, err
+	}
+
+	return &response, nil
+}
+
+func (c *Client) QueryWithDOH(method Method, r Resolver, name string, question uint16) (*dns.Msg, error) {
+	msg := &dns.Msg{}
+	msg.Id = 0
+	msg.Question = make([]dns.Question, 1)
+	msg.Question[0] = dns.Question{
+		Name:   dns.Fqdn(name),
+		Qtype:  question,
+		Qclass: dns.ClassINET,
+	}
+	return c.QueryWithDOHMsg(method, r, msg)
+}
+
+func (c *Client) QueryWithDOHMsg(method Method, r Resolver, msg *dns.Msg) (*dns.Msg, error) {
+	packedMsg, err := msg.Pack()
+	if err != nil {
+		return nil, err
+	}
+
+	var body []byte
+	var dnsParam string
+	switch method {
+	case MethodPost:
+		dnsParam = ""
+		body = packedMsg
+	case MethodGet:
+		dnsParam = base64.RawURLEncoding.EncodeToString(packedMsg)
+		body = nil
+	default:
+		return nil, errors.New("unsupported method")
+	}
+	req, err := retryablehttp.NewRequest(string(method), r.URL, bytes.NewReader(body))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Accept", "application/dns-message")
+	if dnsParam != "" {
+		q := req.URL.Query()
+		q.Add("dns", dnsParam)
+		req.URL.RawQuery = q.Encode()
+	} else if len(body) > 0 {
+		req.Header.Set("Content-Type", "application/dns-message")
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.Body == nil {
+		return nil, errors.New("empty response body")
+	}
+
+	respBodyBytes, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	respMsg := &dns.Msg{}
+	if err := respMsg.Unpack(respBodyBytes); err != nil {
+		return nil, err
+	}
+	return respMsg, nil
+}

doh/doh_client_test.go

@@ -0,0 +1,32 @@
+package doh
+
+import (
+	"testing"
+
+	"github.com/miekg/dns"
+	"github.com/stretchr/testify/require"
+)
+
+func TestConsistentResolve(t *testing.T) {
+	client := New()
+	var lastAnswer string
+	for i := 0; i < 10; i++ {
+		d, err := client.Query("example.com", A)
+		require.Nil(t, err, "could not resolve dns")
+		if lastAnswer == "" {
+			lastAnswer = d.Answer[0].Data
+		} else {
+			require.Equal(t, lastAnswer, d.Answer[0].Data, "got another data from previous")
+		}
+	}
+}
+
+func TestResolvers(t *testing.T) {
+	client := New()
+	d, err := client.QueryWithDOH(MethodGet, OpenDNS, "www.example.com", dns.TypeA)
+	require.Nil(t, err, "could not resolve dns")
+	require.NotNil(t, d, "could not retrieve data")
+	d, err = client.QueryWithDOH(MethodPost, OpenDNS, "www.example.com", dns.TypeA)
+	require.Nil(t, err, "could not resolve dns")
+	require.NotNil(t, d, "could not retrieve data")
+}

doh/options.go

@@ -0,0 +1,72 @@
+package doh
+
+import (
+	"fmt"
+	"net/http"
+
+	retryablehttp "github.com/projectdiscovery/retryablehttp-go"
+)
+
+type Options struct {
+	DefaultResolver Resolver
+	httpClient      *retryablehttp.Client
+}
+
+type Resolver struct {
+	Name string
+	URL  string
+}
+
+var (
+	Cloudflare = Resolver{Name: "Cloudflare", URL: "https://cloudflare-dns.com/dns-query"}
+	Google     = Resolver{Name: "Google", URL: "https://dns.google.com/resolve"}
+	Quad9      = Resolver{Name: "Cloudflare", URL: "https://dns.quad9.net:5053/dns-query"}
+	PowerDNS   = Resolver{Name: "PowerDNS", URL: "https://doh.powerdns.org/dns-query"}
+	OpenDNS    = Resolver{Name: "OpenDNS", URL: "https://doh.opendns.com/dns-query"}
+)
+
+type QuestionType string
+
+func (q QuestionType) ToString() string {
+	return fmt.Sprint(q)
+}
+
+const (
+	A     QuestionType = "A"
+	AAAA  QuestionType = "AAAA"
+	MX    QuestionType = "MX"
+	NS    QuestionType = "NS"
+	SOA   QuestionType = "SOA"
+	PTR   QuestionType = "PTR"
+	CNAME QuestionType = "CNAME"
+)
+
+type Response struct {
+	Status   int        `json:"Status"`
+	TC       bool       `json:"TC"`
+	RD       bool       `json:"RD"`
+	RA       bool       `json:"RA"`
+	AD       bool       `json:"AD"`
+	CD       bool       `json:"CD"`
+	Question []Question `json:"Question"`
+	Answer   []Answer   `json:"Answer"`
+	Comment  string
+}
+
+type Question struct {
+	Name string `json:"name"`
+	Type int    `json:"type"`
+}
+type Answer struct {
+	Name string `json:"name"`
+	Type int    `json:"type"`
+	TTL  int    `json:"TTL"`
+	Data string `json:"data"`
+}
+
+type Method string
+
+const (
+	MethodGet  Method = http.MethodGet
+	MethodPost Method = http.MethodPost
+)

go.mod

@@ -3,6 +3,8 @@ module github.com/projectdiscovery/retryabledns
 go 1.14
 
 require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/miekg/dns v1.1.29
+	github.com/projectdiscovery/retryablehttp-go v1.0.2
 	github.com/stretchr/testify v1.7.0
 )

go.sum

@@ -1,9 +1,12 @@
-github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/miekg/dns v1.1.29 h1:xHBEhR+t5RzcFJjBLJlax2daXOrTYtr9z4WdKEfWFzg=
 github.com/miekg/dns v1.1.29/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/projectdiscovery/retryablehttp-go v1.0.2 h1:LV1/KAQU+yeWhNVlvveaYFsjBYRwXlNEq0PvrezMV0U=
+github.com/projectdiscovery/retryablehttp-go v1.0.2/go.mod h1:dx//aY9V247qHdsRf0vdWHTBZuBQ2vm6Dq5dagxrDYI=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
@@ -13,15 +16,22 @@ golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8U
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-golang.org/x/net v0.0.0-20190923162816-aa69164e4478 h1:l5EDrHhldLYb3ZRHDUhXF7Om7MvYXnkV9/iQNo1lX6g=
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+golang.org/x/net v0.0.0-20210521195947-fe42d452be8f h1:Si4U+UcgJzya9kpiEUJKQvjr512OLli+gL4poHrz93U=
+golang.org/x/net v0.0.0-20210521195947-fe42d452be8f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
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