Add randomized relay headers and configurable user-agent rotation

internal/client/http_headers.go

@@ -0,0 +1,239 @@
+// ==============================================================================
+// MasterHttpRelayVPN
+// Author: MasterkinG32
+// Github: https://github.com/masterking32
+// Year: 2026
+// ==============================================================================
+package client
+
+import (
+	"bufio"
+	"crypto/rand"
+	"encoding/hex"
+	"math/big"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"masterhttprelayvpn/internal/config"
+	"masterhttprelayvpn/internal/logger"
+)
+
+type relayHeaderBuilder struct {
+	cfg               config.Config
+	userAgents        []string
+	refererCandidates []string
+}
+
+func newRelayHeaderBuilder(cfg config.Config, log *logger.Logger) *relayHeaderBuilder {
+	builder := &relayHeaderBuilder{
+		cfg:        cfg,
+		userAgents: loadUserAgents(cfg.HTTPUserAgentsFile, log),
+	}
+
+	builder.refererCandidates = buildRefererCandidates(cfg)
+	return builder
+}
+
+func (b *relayHeaderBuilder) Apply(req *http.Request) {
+	if ua := b.pickUserAgent(); ua != "" {
+		req.Header.Set("User-Agent", ua)
+	}
+
+	if b.cfg.HTTPHeaderProfile == "browser" {
+		req.Header.Set("Accept", pickRandomString(
+			"*/*",
+			"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
+			"application/json,text/plain,*/*",
+		))
+
+		req.Header.Set("Accept-Language", b.pickAcceptLanguage())
+		req.Header.Set("Cache-Control", pickRandomString("no-cache", "max-age=0", "no-store"))
+		req.Header.Set("Pragma", "no-cache")
+		req.Header.Set("Sec-Fetch-Dest", "empty")
+		req.Header.Set("Sec-Fetch-Mode", "cors")
+		req.Header.Set("Sec-Fetch-Site", pickRandomString("same-origin", "same-site", "cross-site"))
+		req.Header.Set("Priority", pickRandomString("u=0, i", "u=1, i"))
+		if referer := b.pickReferer(); referer != "" {
+			req.Header.Set("Referer", referer)
+		}
+	}
+
+	if b.cfg.HTTPRandomizeHeaders {
+		padding := randomPadding(b.cfg.HTTPPaddingMinBytes, b.cfg.HTTPPaddingMaxBytes)
+		if padding != "" {
+			headerName := strings.TrimSpace(b.cfg.HTTPPaddingHeader)
+			if headerName == "" {
+				headerName = "X-Padding"
+			}
+			req.Header.Set(headerName, padding)
+		}
+
+		req.Header.Set("X-Request-Nonce", randomHex(8))
+	}
+}
+
+func (b *relayHeaderBuilder) pickUserAgent() string {
+	if len(b.userAgents) == 0 {
+		return ""
+	}
+
+	return b.userAgents[randomIndex(len(b.userAgents))]
+}
+
+func (b *relayHeaderBuilder) pickReferer() string {
+	if len(b.refererCandidates) == 0 {
+		return ""
+	}
+
+	return b.refererCandidates[randomIndex(len(b.refererCandidates))]
+}
+
+func (b *relayHeaderBuilder) pickAcceptLanguage() string {
+	if strings.TrimSpace(b.cfg.HTTPAcceptLanguage) != "" {
+		return b.cfg.HTTPAcceptLanguage
+	}
+
+	return pickRandomString(
+		"en-US,en;q=0.9",
+		"en-GB,en;q=0.9",
+		"fa-IR,fa;q=0.9,en-US;q=0.7,en;q=0.6",
+		"de-DE,de;q=0.9,en-US;q=0.7,en;q=0.6",
+	)
+}
+
+func loadUserAgents(path string, log *logger.Logger) []string {
+	userAgents := readUserAgentsFromFile(path)
+	if len(userAgents) > 0 {
+		return userAgents
+	}
+
+	if log != nil {
+		log.Warnf("<yellow>user agents file <cyan>%s</cyan> not found or empty, using built-in defaults</yellow>", path)
+	}
+
+	return []string{
+		"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36",
+		"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0",
+		"Mozilla/5.0 (Macintosh; Intel Mac OS X 14_5) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.5 Safari/605.1.15",
+	}
+}
+
+func readUserAgentsFromFile(path string) []string {
+	if strings.TrimSpace(path) == "" {
+		return nil
+	}
+
+	candidates := []string{path}
+	if !filepath.IsAbs(path) {
+		candidates = append(candidates, filepath.Join(".", path))
+	}
+
+	for _, candidate := range candidates {
+		file, err := os.Open(candidate)
+		if err != nil {
+			continue
+		}
+
+		userAgents := make([]string, 0, 16)
+		scanner := bufio.NewScanner(file)
+		for scanner.Scan() {
+			line := strings.TrimSpace(scanner.Text())
+			if line == "" || strings.HasPrefix(line, "#") {
+				continue
+			}
+			userAgents = append(userAgents, line)
+		}
+
+		if len(userAgents) > 0 {
+			_ = file.Close()
+			return userAgents
+		}
+
+		_ = file.Close()
+	}
+
+	return nil
+}
+
+func buildRefererCandidates(cfg config.Config) []string {
+	if strings.TrimSpace(cfg.HTTPReferer) != "" {
+		return []string{cfg.HTTPReferer}
+	}
+
+	relayURL, err := url.Parse(cfg.RelayURL)
+	if err != nil || relayURL.Scheme == "" || relayURL.Host == "" {
+		return nil
+	}
+
+	base := relayURL.Scheme + "://" + relayURL.Host
+	return []string{
+		base + "/",
+		base + "/index.html",
+		base + "/home",
+		base + "/api/status",
+	}
+}
+
+func pickRandomString(values ...string) string {
+	if len(values) == 0 {
+		return ""
+	}
+
+	return values[randomIndex(len(values))]
+}
+
+func randomIndex(length int) int {
+	if length <= 1 {
+		return 0
+	}
+
+	n, err := rand.Int(rand.Reader, big.NewInt(int64(length)))
+	if err != nil {
+		return 0
+	}
+
+	return int(n.Int64())
+}
+
+func randomPadding(minBytes int, maxBytes int) string {
+	if maxBytes <= 0 || maxBytes < minBytes {
+		return ""
+	}
+
+	length := minBytes
+	if maxBytes > minBytes {
+		length += randomIndex(maxBytes - minBytes + 1)
+	}
+
+	if length <= 0 {
+		return ""
+	}
+
+	raw := make([]byte, (length+1)/2)
+	if _, err := rand.Read(raw); err != nil {
+		return ""
+	}
+
+	padding := hex.EncodeToString(raw)
+	if len(padding) > length {
+		padding = padding[:length]
+	}
+
+	return padding
+}
+
+func randomHex(byteCount int) string {
+	if byteCount <= 0 {
+		return ""
+	}
+
+	raw := make([]byte, byteCount)
+	if _, err := rand.Read(raw); err != nil {
+		return ""
+	}
+
+	return hex.EncodeToString(raw)
+}