* move ./*.go files into ./home/ directory

2019-06-10 11:33:19 +03:00
parent 9fe34818e3
commit dc682763ff
27 changed files with 37 additions and 28 deletions
--- a/home/helpers.go
+++ b/home/helpers.go
@@ -0,0 +1,405 @@
+package home
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/AdguardTeam/dnsproxy/upstream"
+	"github.com/AdguardTeam/golibs/log"
+	"github.com/joomcode/errorx"
+)
+
+// ----------------------------------
+// helper functions for HTTP handlers
+// ----------------------------------
+func ensure(method string, handler func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != method {
+			http.Error(w, "This request must be "+method, http.StatusMethodNotAllowed)
+			return
+		}
+
+		if method == "POST" || method == "PUT" || method == "DELETE" {
+			controlLock.Lock()
+			defer controlLock.Unlock()
+		}
+
+		handler(w, r)
+	}
+}
+
+func ensurePOST(handler func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
+	return ensure("POST", handler)
+}
+
+func ensureGET(handler func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
+	return ensure("GET", handler)
+}
+
+// Bridge between http.Handler object and Go function
+type httpHandler struct {
+	handler func(http.ResponseWriter, *http.Request)
+}
+
+func (h *httpHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	h.handler(w, r)
+}
+
+func ensureGETHandler(handler func(http.ResponseWriter, *http.Request)) http.Handler {
+	h := httpHandler{}
+	h.handler = ensure("GET", handler)
+	return &h
+}
+
+func optionalAuth(handler func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if config.AuthName == "" || config.AuthPass == "" {
+			handler(w, r)
+			return
+		}
+		user, pass, ok := r.BasicAuth()
+		if !ok || user != config.AuthName || pass != config.AuthPass {
+			w.Header().Set("WWW-Authenticate", `Basic realm="dnsfilter"`)
+			w.WriteHeader(http.StatusUnauthorized)
+			w.Write([]byte("Unauthorised.\n"))
+			return
+		}
+		handler(w, r)
+	}
+}
+
+type authHandler struct {
+	handler http.Handler
+}
+
+func (a *authHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	optionalAuth(a.handler.ServeHTTP)(w, r)
+}
+
+func optionalAuthHandler(handler http.Handler) http.Handler {
+	return &authHandler{handler}
+}
+
+// -------------------
+// first run / install
+// -------------------
+func detectFirstRun() bool {
+	configfile := config.ourConfigFilename
+	if !filepath.IsAbs(configfile) {
+		configfile = filepath.Join(config.ourWorkingDir, config.ourConfigFilename)
+	}
+	_, err := os.Stat(configfile)
+	if !os.IsNotExist(err) {
+		// do nothing, file exists
+		return false
+	}
+	return true
+}
+
+// preInstall lets the handler run only if firstRun is true, no redirects
+func preInstall(handler func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if !config.firstRun {
+			// if it's not first run, don't let users access it (for example /install.html when configuration is done)
+			http.Error(w, http.StatusText(http.StatusForbidden), http.StatusForbidden)
+			return
+		}
+		handler(w, r)
+	}
+}
+
+// preInstallStruct wraps preInstall into a struct that can be returned as an interface where necessary
+type preInstallHandlerStruct struct {
+	handler http.Handler
+}
+
+func (p *preInstallHandlerStruct) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	preInstall(p.handler.ServeHTTP)(w, r)
+}
+
+// preInstallHandler returns http.Handler interface for preInstall wrapper
+func preInstallHandler(handler http.Handler) http.Handler {
+	return &preInstallHandlerStruct{handler}
+}
+
+// postInstall lets the handler run only if firstRun is false, and redirects to /install.html otherwise
+// it also enforces HTTPS if it is enabled and configured
+func postInstall(handler func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if config.firstRun &&
+			!strings.HasPrefix(r.URL.Path, "/install.") &&
+			r.URL.Path != "/favicon.png" {
+			http.Redirect(w, r, "/install.html", http.StatusSeeOther) // should not be cacheable
+			return
+		}
+		// enforce https?
+		if config.TLS.ForceHTTPS && r.TLS == nil && config.TLS.Enabled && config.TLS.PortHTTPS != 0 && httpsServer.server != nil {
+			// yes, and we want host from host:port
+			host, _, err := net.SplitHostPort(r.Host)
+			if err != nil {
+				// no port in host
+				host = r.Host
+			}
+			// construct new URL to redirect to
+			newURL := url.URL{
+				Scheme:   "https",
+				Host:     net.JoinHostPort(host, strconv.Itoa(config.TLS.PortHTTPS)),
+				Path:     r.URL.Path,
+				RawQuery: r.URL.RawQuery,
+			}
+			http.Redirect(w, r, newURL.String(), http.StatusTemporaryRedirect)
+			return
+		}
+		w.Header().Set("Access-Control-Allow-Origin", "*")
+		handler(w, r)
+	}
+}
+
+type postInstallHandlerStruct struct {
+	handler http.Handler
+}
+
+func (p *postInstallHandlerStruct) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	postInstall(p.handler.ServeHTTP)(w, r)
+}
+
+func postInstallHandler(handler http.Handler) http.Handler {
+	return &postInstallHandlerStruct{handler}
+}
+
+// -------------------------------------------------
+// helper functions for parsing parameters from body
+// -------------------------------------------------
+func parseParametersFromBody(r io.Reader) (map[string]string, error) {
+	parameters := map[string]string{}
+
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if len(line) == 0 {
+			// skip empty lines
+			continue
+		}
+		parts := strings.SplitN(line, "=", 2)
+		if len(parts) != 2 {
+			return parameters, errors.New("Got invalid request body")
+		}
+		parameters[strings.TrimSpace(parts[0])] = strings.TrimSpace(parts[1])
+	}
+
+	return parameters, nil
+}
+
+// ------------------
+// network interfaces
+// ------------------
+type netInterface struct {
+	Name         string   `json:"name"`
+	MTU          int      `json:"mtu"`
+	HardwareAddr string   `json:"hardware_address"`
+	Addresses    []string `json:"ip_addresses"`
+	Flags        string   `json:"flags"`
+}
+
+// getValidNetInterfaces returns interfaces that are eligible for DNS and/or DHCP
+// invalid interface is a ppp interface or the one that doesn't allow broadcasts
+func getValidNetInterfaces() ([]net.Interface, error) {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return nil, fmt.Errorf("Couldn't get list of interfaces: %s", err)
+	}
+
+	netIfaces := []net.Interface{}
+
+	for i := range ifaces {
+		if ifaces[i].Flags&net.FlagPointToPoint != 0 {
+			// this interface is ppp, we're not interested in this one
+			continue
+		}
+
+		iface := ifaces[i]
+		netIfaces = append(netIfaces, iface)
+	}
+
+	return netIfaces, nil
+}
+
+// getValidNetInterfacesMap returns interfaces that are eligible for DNS and WEB only
+// we do not return link-local addresses here
+func getValidNetInterfacesForWeb() ([]netInterface, error) {
+	ifaces, err := getValidNetInterfaces()
+	if err != nil {
+		return nil, errorx.Decorate(err, "Couldn't get interfaces")
+	}
+	if len(ifaces) == 0 {
+		return nil, errors.New("couldn't find any legible interface")
+	}
+
+	var netInterfaces []netInterface
+
+	for _, iface := range ifaces {
+		addrs, e := iface.Addrs()
+		if e != nil {
+			return nil, errorx.Decorate(e, "Failed to get addresses for interface %s", iface.Name)
+		}
+
+		netIface := netInterface{
+			Name:         iface.Name,
+			MTU:          iface.MTU,
+			HardwareAddr: iface.HardwareAddr.String(),
+		}
+
+		if iface.Flags != 0 {
+			netIface.Flags = iface.Flags.String()
+		}
+
+		// we don't want link-local addresses in json, so skip them
+		for _, addr := range addrs {
+			ipnet, ok := addr.(*net.IPNet)
+			if !ok {
+				// not an IPNet, should not happen
+				return nil, fmt.Errorf("SHOULD NOT HAPPEN: got iface.Addrs() element %s that is not net.IPNet, it is %T", addr, addr)
+			}
+			// ignore link-local
+			if ipnet.IP.IsLinkLocalUnicast() {
+				continue
+			}
+			netIface.Addresses = append(netIface.Addresses, ipnet.IP.String())
+		}
+		if len(netIface.Addresses) != 0 {
+			netInterfaces = append(netInterfaces, netIface)
+		}
+	}
+
+	return netInterfaces, nil
+}
+
+// checkPortAvailable is not a cheap test to see if the port is bindable, because it's actually doing the bind momentarily
+func checkPortAvailable(host string, port int) error {
+	ln, err := net.Listen("tcp", net.JoinHostPort(host, strconv.Itoa(port)))
+	if err != nil {
+		return err
+	}
+	ln.Close()
+	return nil
+}
+
+func checkPacketPortAvailable(host string, port int) error {
+	ln, err := net.ListenPacket("udp", net.JoinHostPort(host, strconv.Itoa(port)))
+	if err != nil {
+		return err
+	}
+	ln.Close()
+	return err
+}
+
+// Connect to a remote server resolving hostname using our own DNS server
+func customDialContext(ctx context.Context, network, addr string) (net.Conn, error) {
+	log.Tracef("network:%v  addr:%v", network, addr)
+
+	host, port, err := net.SplitHostPort(addr)
+	if err != nil {
+		return nil, err
+	}
+
+	dialer := &net.Dialer{
+		Timeout: time.Minute * 5,
+	}
+
+	if net.ParseIP(host) != nil || config.DNS.Port == 0 {
+		con, err := dialer.DialContext(ctx, network, addr)
+		return con, err
+	}
+
+	bindhost := config.DNS.BindHost
+	if config.DNS.BindHost == "0.0.0.0" {
+		bindhost = "127.0.0.1"
+	}
+	resolverAddr := fmt.Sprintf("%s:%d", bindhost, config.DNS.Port)
+	r := upstream.NewResolver(resolverAddr, 30*time.Second)
+	addrs, e := r.LookupIPAddr(ctx, host)
+	log.Tracef("LookupIPAddr: %s: %v", host, addrs)
+	if e != nil {
+		return nil, e
+	}
+
+	var firstErr error
+	firstErr = nil
+	for _, a := range addrs {
+		addr = net.JoinHostPort(a.String(), port)
+		con, err := dialer.DialContext(ctx, network, addr)
+		if err != nil {
+			if firstErr == nil {
+				firstErr = err
+			}
+			continue
+		}
+		return con, err
+	}
+	return nil, firstErr
+}
+
+// check if error is "address already in use"
+func errorIsAddrInUse(err error) bool {
+	errOpError, ok := err.(*net.OpError)
+	if !ok {
+		return false
+	}
+
+	errSyscallError, ok := errOpError.Err.(*os.SyscallError)
+	if !ok {
+		return false
+	}
+
+	errErrno, ok := errSyscallError.Err.(syscall.Errno)
+	if !ok {
+		return false
+	}
+
+	if runtime.GOOS == "windows" {
+		const WSAEADDRINUSE = 10048
+		return errErrno == WSAEADDRINUSE
+	}
+
+	return errErrno == syscall.EADDRINUSE
+}
+
+// ---------------------
+// debug logging helpers
+// ---------------------
+func _Func() string {
+	pc := make([]uintptr, 10) // at least 1 entry needed
+	runtime.Callers(2, pc)
+	f := runtime.FuncForPC(pc[0])
+	return path.Base(f.Name())
+}
+
+// Parse input string and return IPv4 address
+func parseIPv4(s string) net.IP {
+	ip := net.ParseIP(s)
+	if ip == nil {
+		return nil
+	}
+
+	v4InV6Prefix := []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff}
+	if !bytes.Equal(ip[0:12], v4InV6Prefix) {
+		return nil
+	}
+
+	return ip.To4()
+}