refactor wip

proxychain/requestmodifers/resolve_with_google_doh.go

@@ -0,0 +1,80 @@
+package requestmodifers
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"ladder/proxychain"
+	"net"
+	"net/http"
+	"time"
+)
+
+// resolveWithGoogleDoH resolves DNS using Google's DNS-over-HTTPS
+func resolveWithGoogleDoH(host string) (string, error) {
+	url := "https://dns.google/resolve?name=" + host + "&type=A"
+	resp, err := http.Get(url)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	var result struct {
+		Answer []struct {
+			Data string `json:"data"`
+		} `json:"Answer"`
+	}
+	err = json.NewDecoder(resp.Body).Decode(&result)
+	if err != nil {
+		return "", err
+	}
+
+	// Get the first A record
+	if len(result.Answer) > 0 {
+		return result.Answer[0].Data, nil
+	}
+	return "", fmt.Errorf("no DoH DNS record found for %s", host)
+}
+
+// ResolveWithGoogleDoH modifies a ProxyChain's client to make the request but resolve the URL
+// using Google's DNS over HTTPs service
+func ResolveWithGoogleDoH() proxychain.RequestModification {
+	return func(px *proxychain.ProxyChain) error {
+		client := &http.Client{
+			Timeout: px.Client.Timeout,
+		}
+
+		dialer := &net.Dialer{
+			Timeout:   5 * time.Second,
+			KeepAlive: 5 * time.Second,
+		}
+
+		customDialContext := func(ctx context.Context, network, addr string) (net.Conn, error) {
+			host, port, err := net.SplitHostPort(addr)
+			if err != nil {
+				// If the addr doesn't include a port, determine it based on the URL scheme
+				if px.Request.URL.Scheme == "https" {
+					port = "443"
+				} else {
+					port = "80"
+				}
+				host = addr // assume the entire addr is the host
+			}
+
+			resolvedHost, err := resolveWithGoogleDoH(host)
+			if err != nil {
+				return nil, err
+			}
+
+			return dialer.DialContext(ctx, network, net.JoinHostPort(resolvedHost, port))
+		}
+
+		patchedTransportWithDoH := &http.Transport{
+			DialContext: customDialContext,
+		}
+
+		client.Transport = patchedTransportWithDoH
+		px.Client = client // Assign the modified client to the ProxyChain
+		return nil
+	}
+}