SpoofDPI/dns/resolver/doh.go
2024-08-19 11:00:26 +09:00

96 lines
1.9 KiB
Go

package resolver
import (
"bytes"
"context"
"encoding/base64"
"errors"
"fmt"
"net"
"net/http"
"regexp"
"time"
"github.com/miekg/dns"
)
type DOHResolver struct {
upstream string
client *http.Client
}
func NewDOHResolver(host string) *DOHResolver {
c := &http.Client{
Timeout: 5 * time.Second,
Transport: &http.Transport{
DialContext: (&net.Dialer{
Timeout: 3 * time.Second,
KeepAlive: 30 * time.Second,
}).DialContext,
TLSHandshakeTimeout: 5 * time.Second,
MaxIdleConnsPerHost: 100,
MaxIdleConns: 100,
},
}
host = regexp.MustCompile(`^https:\/\/|\/dns-query$`).ReplaceAllString(host, "")
return &DOHResolver{
upstream: "https://" + host + "/dns-query",
client: c,
}
}
func (r *DOHResolver) Resolve(ctx context.Context, host string, qTypes []uint16) ([]net.IPAddr, error) {
resultCh := lookupAllTypes(ctx, host, qTypes, r.exchange)
addrs, err := processResults(ctx, resultCh)
return addrs, err
}
func (r *DOHResolver) String() string {
return fmt.Sprintf("doh resolver(%s)", r.upstream)
}
func (r *DOHResolver) exchange(ctx context.Context, msg *dns.Msg) (*dns.Msg, error) {
pack, err := msg.Pack()
if err != nil {
return nil, err
}
url := fmt.Sprintf("%s?dns=%s", r.upstream, base64.RawStdEncoding.EncodeToString(pack))
req, err := http.NewRequest("GET", url, nil)
if err != nil {
return nil, err
}
req = req.WithContext(ctx)
req.Header.Set("Accept", "application/dns-message")
resp, err := r.client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
return nil, errors.New("doh status error")
}
buf := bytes.Buffer{}
_, err = buf.ReadFrom(resp.Body)
if err != nil {
return nil, err
}
resultMsg := new(dns.Msg)
err = resultMsg.Unpack(buf.Bytes())
if err != nil {
return nil, err
}
if resultMsg.Rcode != dns.RcodeSuccess {
return nil, errors.New("doh rcode wasn't successful")
}
return resultMsg, nil
}