path: root/tunnel/tools/libwg-go/http-proxy.go

package main

import (
	"fmt"
	"io"
	"net"
	"net/http"
	"net/netip"
	"net/url"
	"strings"
	"sync"

	"github.com/elazarl/goproxy"

	"golang.zx2c4.com/wireguard/device"

	"gopkg.in/olebedev/go-duktape.v3"
)

const (
	// Imported from Firefox' ProxyAutoConfig.cpp
	// https://searchfox.org/mozilla-central/source/netwerk/base/ProxyAutoConfig.cpp
	// This Source Code Form is subject to the terms of the Mozilla Public
	// License, v. 2.0. If a copy of the MPL was not distributed with this
	// file, You can obtain one at http://mozilla.org/MPL/2.0/.
	ASCII_PAC_UTILS = "function dnsDomainIs(host, domain) {\n" +
		"    return (host.length >= domain.length &&\n" +
		"            host.substring(host.length - domain.length) == domain);\n" +
		"}\n" +
		"" +
		"function dnsDomainLevels(host) {\n" +
		"    return host.split('.').length - 1;\n" +
		"}\n" +
		"" +
		"function isValidIpAddress(ipchars) {\n" +
		"    var matches = " +
		"/^(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})$/.exec(ipchars);\n" +
		"    if (matches == null) {\n" +
		"        return false;\n" +
		"    } else if (matches[1] > 255 || matches[2] > 255 || \n" +
		"               matches[3] > 255 || matches[4] > 255) {\n" +
		"        return false;\n" +
		"    }\n" +
		"    return true;\n" +
		"}\n" +
		"" +
		"function convert_addr(ipchars) {\n" +
		"    var bytes = ipchars.split('.');\n" +
		"    var result = ((bytes[0] & 0xff) << 24) |\n" +
		"                 ((bytes[1] & 0xff) << 16) |\n" +
		"                 ((bytes[2] & 0xff) <<  8) |\n" +
		"                  (bytes[3] & 0xff);\n" +
		"    return result;\n" +
		"}\n" +
		"" +
		"function isInNet(ipaddr, pattern, maskstr) {\n" +
		"    if (!isValidIpAddress(pattern) || !isValidIpAddress(maskstr)) {\n" +
		"        return false;\n" +
		"    }\n" +
		"    if (!isValidIpAddress(ipaddr)) {\n" +
		"        ipaddr = dnsResolve(ipaddr);\n" +
		"        if (ipaddr == null) {\n" +
		"            return false;\n" +
		"        }\n" +
		"    }\n" +
		"    var host = convert_addr(ipaddr);\n" +
		"    var pat  = convert_addr(pattern);\n" +
		"    var mask = convert_addr(maskstr);\n" +
		"    return ((host & mask) == (pat & mask));\n" +
		"    \n" +
		"}\n" +
		"" +
		"function isPlainHostName(host) {\n" +
		"    return (host.search('(\\\\.)|:') == -1);\n" +
		"}\n" +
		"" +
		"function isResolvable(host) {\n" +
		"    var ip = dnsResolve(host);\n" +
		"    return (ip != null);\n" +
		"}\n" +
		"" +
		"function localHostOrDomainIs(host, hostdom) {\n" +
		"    return (host == hostdom) ||\n" +
		"           (hostdom.lastIndexOf(host + '.', 0) == 0);\n" +
		"}\n" +
		"" +
		"function shExpMatch(url, pattern) {\n" +
		"   pattern = pattern.replace(/\\./g, '\\\\.');\n" +
		"   pattern = pattern.replace(/\\*/g, '.*');\n" +
		"   pattern = pattern.replace(/\\?/g, '.');\n" +
		"   var newRe = new RegExp('^'+pattern+'$');\n" +
		"   return newRe.test(url);\n" +
		"}\n" +
		"" +
		"var wdays = {SUN: 0, MON: 1, TUE: 2, WED: 3, THU: 4, FRI: 5, SAT: 6};\n" +
		"var months = {JAN: 0, FEB: 1, MAR: 2, APR: 3, MAY: 4, JUN: 5, JUL: 6, " +
		"AUG: 7, SEP: 8, OCT: 9, NOV: 10, DEC: 11};\n" +
		"" +
		"function weekdayRange() {\n" +
		"    function getDay(weekday) {\n" +
		"        if (weekday in wdays) {\n" +
		"            return wdays[weekday];\n" +
		"        }\n" +
		"        return -1;\n" +
		"    }\n" +
		"    var date = new Date();\n" +
		"    var argc = arguments.length;\n" +
		"    var wday;\n" +
		"    if (argc < 1)\n" +
		"        return false;\n" +
		"    if (arguments[argc - 1] == 'GMT') {\n" +
		"        argc--;\n" +
		"        wday = date.getUTCDay();\n" +
		"    } else {\n" +
		"        wday = date.getDay();\n" +
		"    }\n" +
		"    var wd1 = getDay(arguments[0]);\n" +
		"    var wd2 = (argc == 2) ? getDay(arguments[1]) : wd1;\n" +
		"    return (wd1 == -1 || wd2 == -1) ? false\n" +
		"                                    : (wd1 <= wd2) ? (wd1 <= wday && wday " +
		"<= wd2)\n" +
		"                                                   : (wd2 >= wday || wday " +
		">= wd1);\n" +
		"}\n" +
		"" +
		"function dateRange() {\n" +
		"    function getMonth(name) {\n" +
		"        if (name in months) {\n" +
		"            return months[name];\n" +
		"        }\n" +
		"        return -1;\n" +
		"    }\n" +
		"    var date = new Date();\n" +
		"    var argc = arguments.length;\n" +
		"    if (argc < 1) {\n" +
		"        return false;\n" +
		"    }\n" +
		"    var isGMT = (arguments[argc - 1] == 'GMT');\n" +
		"\n" +
		"    if (isGMT) {\n" +
		"        argc--;\n" +
		"    }\n" +
		"    // function will work even without explict handling of this case\n" +
		"    if (argc == 1) {\n" +
		"        var tmp = parseInt(arguments[0]);\n" +
		"        if (isNaN(tmp)) {\n" +
		"            return ((isGMT ? date.getUTCMonth() : date.getMonth()) ==\n" +
		"                     getMonth(arguments[0]));\n" +
		"        } else if (tmp < 32) {\n" +
		"            return ((isGMT ? date.getUTCDate() : date.getDate()) == " +
		"tmp);\n" +
		"        } else { \n" +
		"            return ((isGMT ? date.getUTCFullYear() : date.getFullYear()) " +
		"==\n" +
		"                     tmp);\n" +
		"        }\n" +
		"    }\n" +
		"    var year = date.getFullYear();\n" +
		"    var date1, date2;\n" +
		"    date1 = new Date(year,  0,  1,  0,  0,  0);\n" +
		"    date2 = new Date(year, 11, 31, 23, 59, 59);\n" +
		"    var adjustMonth = false;\n" +
		"    for (var i = 0; i < (argc >> 1); i++) {\n" +
		"        var tmp = parseInt(arguments[i]);\n" +
		"        if (isNaN(tmp)) {\n" +
		"            var mon = getMonth(arguments[i]);\n" +
		"            date1.setMonth(mon);\n" +
		"        } else if (tmp < 32) {\n" +
		"            adjustMonth = (argc <= 2);\n" +
		"            date1.setDate(tmp);\n" +
		"        } else {\n" +
		"            date1.setFullYear(tmp);\n" +
		"        }\n" +
		"    }\n" +
		"    for (var i = (argc >> 1); i < argc; i++) {\n" +
		"        var tmp = parseInt(arguments[i]);\n" +
		"        if (isNaN(tmp)) {\n" +
		"            var mon = getMonth(arguments[i]);\n" +
		"            date2.setMonth(mon);\n" +
		"        } else if (tmp < 32) {\n" +
		"            date2.setDate(tmp);\n" +
		"        } else {\n" +
		"            date2.setFullYear(tmp);\n" +
		"        }\n" +
		"    }\n" +
		"    if (adjustMonth) {\n" +
		"        date1.setMonth(date.getMonth());\n" +
		"        date2.setMonth(date.getMonth());\n" +
		"    }\n" +
		"    if (isGMT) {\n" +
		"    var tmp = date;\n" +
		"        tmp.setFullYear(date.getUTCFullYear());\n" +
		"        tmp.setMonth(date.getUTCMonth());\n" +
		"        tmp.setDate(date.getUTCDate());\n" +
		"        tmp.setHours(date.getUTCHours());\n" +
		"        tmp.setMinutes(date.getUTCMinutes());\n" +
		"        tmp.setSeconds(date.getUTCSeconds());\n" +
		"        date = tmp;\n" +
		"    }\n" +
		"    return (date1 <= date2) ? (date1 <= date) && (date <= date2)\n" +
		"                            : (date2 >= date) || (date >= date1);\n" +
		"}\n" +
		"" +
		"function timeRange() {\n" +
		"    var argc = arguments.length;\n" +
		"    var date = new Date();\n" +
		"    var isGMT= false;\n" +
		"" +
		"    if (argc < 1) {\n" +
		"        return false;\n" +
		"    }\n" +
		"    if (arguments[argc - 1] == 'GMT') {\n" +
		"        isGMT = true;\n" +
		"        argc--;\n" +
		"    }\n" +
		"\n" +
		"    var hour = isGMT ? date.getUTCHours() : date.getHours();\n" +
		"    var date1, date2;\n" +
		"    date1 = new Date();\n" +
		"    date2 = new Date();\n" +
		"\n" +
		"    if (argc == 1) {\n" +
		"        return (hour == arguments[0]);\n" +
		"    } else if (argc == 2) {\n" +
		"        return ((arguments[0] <= hour) && (hour <= arguments[1]));\n" +
		"    } else {\n" +
		"        switch (argc) {\n" +
		"        case 6:\n" +
		"            date1.setSeconds(arguments[2]);\n" +
		"            date2.setSeconds(arguments[5]);\n" +
		"        case 4:\n" +
		"            var middle = argc >> 1;\n" +
		"            date1.setHours(arguments[0]);\n" +
		"            date1.setMinutes(arguments[1]);\n" +
		"            date2.setHours(arguments[middle]);\n" +
		"            date2.setMinutes(arguments[middle + 1]);\n" +
		"            if (middle == 2) {\n" +
		"                date2.setSeconds(59);\n" +
		"            }\n" +
		"            break;\n" +
		"        default:\n" +
		"          throw 'timeRange: bad number of arguments'\n" +
		"        }\n" +
		"    }\n" +
		"\n" +
		"    if (isGMT) {\n" +
		"        date.setFullYear(date.getUTCFullYear());\n" +
		"        date.setMonth(date.getUTCMonth());\n" +
		"        date.setDate(date.getUTCDate());\n" +
		"        date.setHours(date.getUTCHours());\n" +
		"        date.setMinutes(date.getUTCMinutes());\n" +
		"        date.setSeconds(date.getUTCSeconds());\n" +
		"    }\n" +
		"    return (date1 <= date2) ? (date1 <= date) && (date <= date2)\n" +
		"                            : (date2 >= date) || (date >= date1);\n" +
		"\n" +
		"}\n"
)

type HttpProxy struct {
	listener net.Listener
	tlsListener net.Listener
	logger *device.Logger
	addrPort netip.AddrPort
	tlsAddrPort netip.AddrPort
	ctx *duktape.Context
	defaultProxy *goproxy.ProxyHttpServer
	uidRequest chan UidRequest
	handlers []*HttpHandler
}

func NewHttpProxy(uidRequest chan UidRequest, logger *device.Logger) *HttpProxy {
	logger.Verbosef("NewHttpProxy")
	return &HttpProxy{
		listener: nil,
		logger: logger,
		uidRequest: uidRequest,
		handlers: make([]*HttpHandler, 0, 2),
	}
}

var (
	ASCII_PAC_UTILS_NAMES = []string{"dnsDomainIs", "dnsDomainLevels", "isValidIpAddress", "convert_addr", "isInNet", "isPlainHostName", "isResolvable", "localHostOrDomainIs", "shExpMatch", "weekdayRange", "dateRange", "timeRange"}
)

func (p *HttpProxy) GetAddrPort() netip.AddrPort {
	return p.addrPort
}

type Logger struct {
	logger *device.Logger
}

func (l *Logger) Printf(format string, v ...interface{}) {
	l.logger.Verbosef(format, v...)
}

func (p *HttpProxy) newGoProxy(proxyUrl string) *goproxy.ProxyHttpServer {
	proxy := goproxy.NewProxyHttpServer()
	proxy.Logger = &Logger{logger: p.logger}
	proxy.Verbose = true
	proxy.NonproxyHandler = http.HandlerFunc(func (w http.ResponseWriter, req *http.Request) {
		if req.Host == "" {
			fmt.Fprintln(w, "Cannot handle requests without Host header, e.g., HTTP 1.0")
			return
		}
		req.URL.Scheme = "http"
		req.URL.Host = req.Host
		proxy.ServeHTTP(w, req)
	})

	if proxyUrl != "" {
		proxy.Tr.Proxy = func(req *http.Request) (*url.URL, error) {
			return url.Parse(proxyUrl)
		}
		proxy.ConnectDial = proxy.NewConnectDialToProxy(proxyUrl)
	}

	return proxy
}

func FindProxyForURL(ctx *duktape.Context, url, host string, logger *device.Logger) (res string, err error) {
	if !ctx.GetGlobalString("FindProxyForURL") {
		ctx.Pop()
		return "", fmt.Errorf("FindProxyForURL not found")
	}

	ctx.PushString(url)
	ctx.PushString(host)

	res = "DIRECT"
	logger.Verbosef("Before pcall")
	r := ctx.Pcall(2)
	logger.Verbosef("After pcall")
	if r == 0 {
		res = ctx.GetString(-1)
	} else if ctx.IsError(-1) {
		ctx.GetPropString(-1, "stack")
		err = fmt.Errorf("Error: %v", ctx.SafeToString(-1))
	} else {
		err = fmt.Errorf("Error: %v", ctx.SafeToString(-1))
	}
	ctx.Pop()
	return
}


func FindProxyForPkg(ctx *duktape.Context, pkg string, logger *device.Logger) (res string, err error) {
	if !ctx.GetGlobalString("FindProxyForPkg") {
		ctx.Pop()
		return "", fmt.Errorf("FindProxyForPkg not found")
	}

	ctx.PushString(pkg)

	res = "DIRECT"
	logger.Verbosef("Before pcall")
	r := ctx.Pcall(1)
	logger.Verbosef("After pcall")
	if r == 0 {
		res = ctx.GetString(-1)
	} else if ctx.IsError(-1) {
		ctx.GetPropString(-1, "stack")
		err = fmt.Errorf("Error: %v", ctx.SafeToString(-1))
	} else {
		err = fmt.Errorf("Error: %v", ctx.SafeToString(-1))
	}
	ctx.Pop()
	return
}

func newPacBodyCtx(body string, logger *device.Logger) *duktape.Context {
	ctx := duktape.New()
	ctx.PushGlobalGoFunction("dnsResolve",
		func(ctx *duktape.Context) int {
			// Check stack
			host := ctx.GetString(-1)
			ctx.Pop()
			ips, err := net.LookupIP(host)
			if err != nil {
				return 0
			}

			for _, ip := range(ips) {
				ipStr := string(ip)
				if strings.Contains(ipStr, ".") {
					// Found IPv4
					ctx.PushString(ipStr)
					return 1
				}
			}
			// No IPv4
			return 0
		})

	ctx.PevalString(ASCII_PAC_UTILS)
	logger.Verbosef("ASCII_PAC_UTILS result is: %v stack:%v", ctx.GetType(-1), ctx.GetTop())
	ctx.Pop()

	ctx.PevalString(string(body))
	logger.Verbosef("result is: %v stack:%v", ctx.GetType(-1), ctx.GetTop())
	ctx.Pop()
	FindProxyForURL(ctx, "http://www.jabra.se/", "www.jabra.se", logger)
	return ctx
}

func (p *HttpProxy) newPacFileCtx(pacFileUrl *url.URL) (*duktape.Context, error) {
	var pacFileBody = ""
	if pacFileUrl == nil {
		return nil, nil
	}

	resp, err := http.Get(pacFileUrl.String())
	p.logger.Verbosef("pacFile: %v, %v", resp, err)

	if err == nil {
		defer resp.Body.Close()
		ct, ok := resp.Header["Content-Type"]
		if ok && len(ct) == 1 && ct[0] == "application/x-ns-proxy-autoconfig" {
			body, err := io.ReadAll(resp.Body)
			if err == nil {
				pacFileBody = string(body)
				return newPacBodyCtx(pacFileBody, p.logger), nil
			}
		}
	}

	return nil, err
}

func (p *HttpProxy) SetPacFileUrl(pacFileUrl *url.URL) error {
	ctx, err := p.newPacFileCtx(pacFileUrl)
	if err != nil {
		return err
	}

	for _, handler := range(p.handlers) {
		handler.setPacCtx(ctx)
	}

	if p.ctx != nil {
		p.ctx.Destroy()
	}
	p.ctx = ctx
	return nil
}

func (p *HttpProxy) SetPacFileContent(pacFile string) error {
	ctx := newPacBodyCtx(pacFile, p.logger)

	for _, handler := range(p.handlers) {
		handler.setPacCtx(ctx)
	}

	if p.ctx != nil {
		p.ctx.Destroy()
	}
	p.ctx = ctx
	return nil
}

func (p *HttpProxy) Start() (listen_port uint16, err error) {
	p.logger.Verbosef("HttpProxy.Start()")
	listen_port = 0


	proxyMap := make(map[string]*goproxy.ProxyHttpServer)

	p.defaultProxy = p.newGoProxy("")
	proxyMap[""] = p.defaultProxy

	listen_port, handler, err := p.startRegularProxy(proxyMap)
	if err != nil {
		return
	}
	p.handlers = append(p.handlers, handler)

	return
}

func (p *HttpProxy) startRegularProxy(proxyMap map[string]*goproxy.ProxyHttpServer) (listen_port uint16, handler *HttpHandler, err error) {
	p.listener, err = net.Listen("tcp", "[::]:")
	if err != nil {
		return
	}

	p.addrPort, err = netip.ParseAddrPort(p.listener.Addr().String())
	if err != nil {
		return
	}

	listen_port = p.addrPort.Port()

	handler = NewHttpHandler(p, p.defaultProxy, proxyMap, p.logger)

	go http.Serve(NewListener(p.listener, handler, p.logger), handler)
	return
}

func (p *HttpProxy) Stop() {
	if p.listener != nil {
		p.logger.Verbosef("Close: %v", p.listener)
		p.listener.Close()
//		p.listener = nil
	}
	if p.tlsListener != nil {
		p.logger.Verbosef("Close: %v", p.tlsListener)
		p.tlsListener.Close()
//		p.tlsListener = nil
	}
	if p.ctx != nil {
		p.ctx.DestroyHeap()
		p.ctx = nil
	}
}

type HttpHandler struct {
	p *HttpProxy
	defaultProxy *goproxy.ProxyHttpServer
	logger *device.Logger
	remoteAddrPkgMapMutex sync.RWMutex
	remoteAddrPkgMap map[string]*goproxy.ProxyHttpServer
	uidRequest chan UidRequest
	ctx *duktape.Context
	proxyMap map[string]*goproxy.ProxyHttpServer
}

func NewHttpHandler(p *HttpProxy, defaultProxy *goproxy.ProxyHttpServer, proxyMap map[string]*goproxy.ProxyHttpServer, logger *device.Logger) *HttpHandler{
	h := &HttpHandler{
		p: p,
		defaultProxy: defaultProxy,
		logger: logger,
		remoteAddrPkgMapMutex: sync.RWMutex{},
		remoteAddrPkgMap: make(map[string]*goproxy.ProxyHttpServer),
		uidRequest: p.uidRequest,
		proxyMap: proxyMap,
	}

	return h
}

// TODO fix multi-threading
func (h *HttpHandler) setPacCtx(ctx *duktape.Context) {
	h.ctx = ctx
}

func (h *HttpHandler) addConnToProxyMap(c net.Conn) error {
	h.logger.Verbosef("Accept: %v -> %v", c.RemoteAddr().String(), c.LocalAddr().String())
	local, err := netip.ParseAddrPort(c.RemoteAddr().String())
	if err != nil {
		return fmt.Errorf("Bad local address (%v): %v", c.RemoteAddr(), err)
	}
	// Remove IPv6 zone, NOOP on IPv4
	local = netip.AddrPortFrom(local.Addr().WithZone(""), local.Port())

	remote, err := netip.ParseAddrPort(c.LocalAddr().String())
	if err != nil {
		return fmt.Errorf("Bad remote address (%v): %v", c.LocalAddr(), err)
	}

	h.logger.Verbosef("uidRequest: %v -> %v", local, remote)
	addrPortPair := AddrPortPair{local: local, remote: remote}
	retCh := make(chan string)
	h.uidRequest <- UidRequest{Data: addrPortPair, RetCh: retCh}

	select {
	case pkg := <-retCh:
		h.logger.Verbosef("uidResponse: '%v'", pkg)

		proxy, ok := h.proxyMap[pkg]
		if !ok {
			proxy = h.findProxyForPkg(pkg)
		}

		if proxy != nil {
			h.remoteAddrPkgMapMutex.Lock()
			h.remoteAddrPkgMap[c.RemoteAddr().String()] = proxy
			h.remoteAddrPkgMapMutex.Unlock()
		}
	}

	return nil
}

func (h *HttpHandler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
	h.remoteAddrPkgMapMutex.Lock()
	proxy, ok := h.remoteAddrPkgMap[req.RemoteAddr]
	if ok && proxy != nil {
		delete(h.remoteAddrPkgMap, req.RemoteAddr)
		h.remoteAddrPkgMapMutex.Unlock()

		proxyStr := "nil"
		proxyUrl, err := proxy.Tr.Proxy(req)
		if err == nil && proxyUrl != nil {
			proxyStr = proxyUrl.String()
		}
		h.logger.Verbosef("ServeHTTP remote:%s proxy:%v", req.RemoteAddr, proxyStr)

		proxy.ServeHTTP(rw, req)
	} else {
		h.remoteAddrPkgMapMutex.Unlock()
		h.defaultProxy.ServeHTTP(rw, req)
	}
}

func (h *HttpHandler) findProxyForPkg(pkg string) *goproxy.ProxyHttpServer {
	if h.ctx == nil {
		return nil
	}

	find := func() (cat string, res string, err error) {
		h.logger.Verbosef("Call FindProxyForPkg %v %v", pkg)
		res, err = FindProxyForPkg(h.ctx, pkg, h.logger)
		h.logger.Verbosef("FindProxyForPkg res %v %v", res, err)
		if err != nil {
			h.logger.Verbosef("FindProxyForPkg result is: %v stack:%v", res, h.ctx.GetTop())
				return "", "", err
		} else {
			values := strings.Split(strings.Trim(res, " "), ";")
			for _, v := range values {
				value := strings.Trim(v, " ")
				parts := strings.SplitN(value, " ", 2)
				if parts[0] == "PROXY" {
					return parts[0], parts[1], nil
				} else if parts[0] == "DIRECT" {
					return parts[0], "", nil
				}
			}
			}
		return "", "", fmt.Errorf("No result")
	}
	cat, res, err := find()
	if err != nil {
		return nil
	}

	var proxy *goproxy.ProxyHttpServer
	if cat == "PROXY" {
		proxy = h.p.newGoProxy("http://" + res)
	} else {
		proxy = h.defaultProxy
	}
	h.proxyMap[pkg] = proxy

	return proxy
}

type AddrPortPair struct {
	local netip.AddrPort
	remote netip.AddrPort
}

// Listener
type Listener struct {
	l net.Listener
	handler *HttpHandler
	logger *device.Logger
}

func NewListener(listener net.Listener, handler *HttpHandler, logger *device.Logger) *Listener{
	l := &Listener{
		l: listener,
		handler: handler,
		logger: logger,
	}

	return l
}

func (l *Listener) Accept() (net.Conn, error) {
	c, err := l.l.Accept()
	if err != nil {
		l.logger.Verbosef("Accept failed: %v", err)
		return c, err
	}

	if err := l.handler.addConnToProxyMap(c); err != nil {
		err = fmt.Errorf("Reject connection (%v): %v", c, err)
		c.Close()
		return nil, err
	}

	return c, nil
}

func (l *Listener) Close() error {
	return l.l.Close()
}

func (l *Listener) Addr() net.Addr {
	return l.l.Addr()
}