bump snap version

feat: Hola API communication failover

Dockerfile

@@ -1,8 +1,10 @@
 FROM golang AS build
 
+ARG GIT_DESC=undefined
+
 WORKDIR /go/src/github.com/Snawoot/hola-proxy
 COPY . .
-RUN CGO_ENABLED=0 go build -a -tags netgo -ldflags '-s -w -extldflags "-static"'
+RUN CGO_ENABLED=0 go build -a -tags netgo -ldflags '-s -w -extldflags "-static" -X main.version='"$GIT_DESC"
 ADD https://curl.haxx.se/ca/cacert.pem /certs.crt
 RUN chmod 0644 /certs.crt
 

Makefile

@@ -1,7 +1,8 @@
 PROGNAME = hola-proxy
 OUTSUFFIX = bin/$(PROGNAME)
+VERSION := $(shell git describe)
 BUILDOPTS = -a -tags netgo
-LDFLAGS = -ldflags '-s -w -extldflags "-static"'
+LDFLAGS = -ldflags '-s -w -extldflags "-static" -X main.version=$(VERSION)'
 
 src = $(wildcard *.go)
 
@@ -59,9 +60,12 @@ fmt:
 	go fmt ./...
 
 run:
-	go run .
+	go run $(LDFLAGS) .
 
-.PHONY: clean all native fmt \
+install:
+	go install $(BUILDOPTS) $(LDFLAGS) .
+
+.PHONY: clean all native fmt install \
 	bin-native \
 	bin-linux-amd64 \
 	bin-linux-386 \

README.md

@@ -44,7 +44,7 @@ Pre-built binaries available on [releases](https://github.com/Snawoot/hola-proxy
 Alternatively, you may install hola-proxy from source. Run within source directory
 
 ```
-go install
+make install
 ```
 
 #### Docker

credservice.go

@@ -2,12 +2,12 @@ package main
 
 import (
 	"context"
+	"net/http"
 	"sync"
 	"time"
 )
 
 const DEFAULT_LIST_LIMIT = 3
-const API_CALL_ATTEMPTS = 3
 
 func CredService(interval, timeout time.Duration,
 	country string,
@@ -24,15 +24,21 @@ func CredService(interval, timeout time.Duration,
 		return
 	}
 
-	for i := 0; i < API_CALL_ATTEMPTS; i++ {
-		ctx, _ := context.WithTimeout(context.Background(), timeout)
-		tunnels, user_uuid, err = Tunnels(ctx, country, proxytype, DEFAULT_LIST_LIMIT)
-		if err == nil {
-			break
+	tx_res, tx_err := EnsureTransaction(context.Background(), timeout, func(ctx context.Context, client *http.Client) bool {
+		tunnels, user_uuid, err = Tunnels(ctx, client, country, proxytype, DEFAULT_LIST_LIMIT)
+		if err != nil {
+			logger.Error("Configuration bootstrap error: %v. Retrying with the fallback mechanism...", err)
+			return false
 		}
+		return true
+	})
+	if tx_err != nil {
+		logger.Critical("Transaction recovery mechanism failure: %v", tx_err)
+		err = tx_err
+		return
 	}
-	if err != nil {
-		logger.Critical("Configuration bootstrap failed: %v", err)
+	if !tx_res {
+		logger.Critical("All attempts failed.")
 		return
 	}
 	auth_header = basic_auth_header(LOGIN_PREFIX+user_uuid,
@@ -48,23 +54,28 @@ func CredService(interval, timeout time.Duration,
 		for {
 			<-ticker.C
 			logger.Info("Rotating credentials...")
-			for i := 0; i < API_CALL_ATTEMPTS; i++ {
-				ctx, _ := context.WithTimeout(context.Background(), timeout)
-				tuns, user_uuid, err = Tunnels(ctx, country, proxytype, DEFAULT_LIST_LIMIT)
-				if err == nil {
-					break
+			tx_res, tx_err := EnsureTransaction(context.Background(), timeout, func(ctx context.Context, client *http.Client) bool {
+				tuns, user_uuid, err = Tunnels(ctx, client, country, proxytype, DEFAULT_LIST_LIMIT)
+				if err != nil {
+					logger.Error("Credential rotation error: %v. Retrying with the fallback mechanism...", err)
+					return false
 				}
+				return true
+			})
+			if tx_err != nil {
+				logger.Critical("Transaction recovery mechanism failure: %v", tx_err)
+				err = tx_err
+				continue
 			}
-			if err != nil {
-				logger.Error("Credential rotation failed after %d attempts. Error: %v",
-					API_CALL_ATTEMPTS, err)
-			} else {
-				(&mux).Lock()
-				auth_header = basic_auth_header(LOGIN_PREFIX+user_uuid,
-					tuns.AgentKey)
-				(&mux).Unlock()
-				logger.Info("Credentials rotated successfully.")
+			if !tx_res {
+				logger.Critical("All rotation attempts failed.")
+				continue
 			}
+			(&mux).Lock()
+			auth_header = basic_auth_header(LOGIN_PREFIX+user_uuid,
+				tuns.AgentKey)
+			(&mux).Unlock()
+			logger.Info("Credentials rotated successfully.")
 		}
 	}()
 	return

csrand.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	crand "crypto/rand"
+	"math/big"
+)
+
+type secureRandomSource struct{}
+
+var RandomSource secureRandomSource
+
+var int63Limit = big.NewInt(0).Lsh(big.NewInt(1), 63)
+
+func (_ secureRandomSource) Seed(_ int64) {
+}
+
+func (_ secureRandomSource) Int63() int64 {
+	randNum, err := crand.Int(crand.Reader, int63Limit)
+	if err != nil {
+		panic(err)
+	}
+	return randNum.Int64()
+}

holaapi.go

@@ -3,17 +3,22 @@ package main
 import (
 	"bytes"
 	"context"
+	"encoding/base64"
 	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/campoy/unique"
-	"github.com/google/uuid"
 	"io/ioutil"
 	"math/rand"
+	"net"
 	"net/http"
 	"net/url"
 	"strconv"
+	"sync"
+	"time"
+
+	"github.com/campoy/unique"
+	"github.com/google/uuid"
 )
 
 const USER_AGENT = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.72 Safari/537.36"
@@ -25,6 +30,8 @@ const VPN_COUNTRIES_URL = CCGI_URL + "vpn_countries.json"
 const BG_INIT_URL = CCGI_URL + "background_init"
 const ZGETTUNNELS_URL = CCGI_URL + "zgettunnels"
 const LOGIN_PREFIX = "user-uuid-"
+const FALLBACK_CONF_URL = "https://www.dropbox.com/s/jemizcvpmf2qb9v/cloud_failover.conf?dl=1"
+const AGENT_SUFFIX = ".hola.org"
 
 var TemporaryBanError = errors.New("temporary ban detected")
 var PermanentBanError = errors.New("permanent ban detected")
@@ -57,11 +64,66 @@ type ZGetTunnelsResponse struct {
 	Ztun       map[string][]string `json:"ztun"`
 }
 
-func do_req(ctx context.Context, method, url string, query, data url.Values) ([]byte, error) {
+type FallbackAgent struct {
+	Name string `json:"name"`
+	IP   string `json:"ip"`
+	Port uint16 `json:"port"`
+}
+
+type fallbackConfResponse struct {
+	Agents    []FallbackAgent `json:"agents"`
+	UpdatedAt int64           `json:"updated_ts"`
+	TTL       int64           `json:"ttl_ms"`
+}
+
+type FallbackConfig struct {
+	Agents    []FallbackAgent
+	UpdatedAt time.Time
+	TTL       time.Duration
+}
+
+func (c *FallbackConfig) UnmarshalJSON(data []byte) error {
+	r := fallbackConfResponse{}
+	err := json.Unmarshal(data, &r)
+	if err != nil {
+		return err
+	}
+	c.Agents = r.Agents
+	c.UpdatedAt = time.Unix(r.UpdatedAt/1000, (r.UpdatedAt%1000)*1000000)
+	c.TTL = time.Duration(r.TTL * 1000000)
+	return nil
+}
+
+func (c *FallbackConfig) Expired() bool {
+	return time.Now().After(c.UpdatedAt.Add(c.TTL))
+}
+
+func (c *FallbackConfig) ShuffleAgents() {
+	rand.New(RandomSource).Shuffle(len(c.Agents), func(i, j int) {
+		c.Agents[i], c.Agents[j] = c.Agents[j], c.Agents[i]
+	})
+}
+
+func (c *FallbackConfig) Clone() *FallbackConfig {
+	return &FallbackConfig{
+		Agents: append([]FallbackAgent(nil), c.Agents...),
+		UpdatedAt: c.UpdatedAt,
+		TTL: c.TTL,
+	}
+}
+
+func (a *FallbackAgent) ToProxy() *url.URL {
+	return &url.URL{
+		Scheme: "https",
+		Host: net.JoinHostPort(a.Name+AGENT_SUFFIX,
+			fmt.Sprintf("%d", a.Port)),
+	}
+}
+
+func do_req(ctx context.Context, client *http.Client, method, url string, query, data url.Values) ([]byte, error) {
 	var (
-		client http.Client
-		req    *http.Request
-		err    error
+		req *http.Request
+		err error
 	)
 	if method == "" {
 		method = "GET"
@@ -91,7 +153,7 @@ func do_req(ctx context.Context, method, url string, query, data url.Values) ([]
 	switch resp.StatusCode {
 	case http.StatusOK, http.StatusCreated, http.StatusAccepted, http.StatusNoContent:
 	default:
-		return nil, errors.New(fmt.Sprintf("Bad HTTP response: %d %s", resp.StatusCode, resp.Status))
+		return nil, errors.New(fmt.Sprintf("Bad HTTP response: %s", resp.Status))
 	}
 	body, err := ioutil.ReadAll(resp.Body)
 	resp.Body.Close()
@@ -101,10 +163,10 @@ func do_req(ctx context.Context, method, url string, query, data url.Values) ([]
 	return body, nil
 }
 
-func VPNCountries(ctx context.Context) (res CountryList, err error) {
+func VPNCountries(ctx context.Context, client *http.Client) (res CountryList, err error) {
 	params := make(url.Values)
 	params.Add("browser", EXT_BROWSER)
-	data, err := do_req(ctx, "", VPN_COUNTRIES_URL, params, nil)
+	data, err := do_req(ctx, client, "", VPN_COUNTRIES_URL, params, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -119,13 +181,13 @@ func VPNCountries(ctx context.Context) (res CountryList, err error) {
 	return
 }
 
-func background_init(ctx context.Context, user_uuid string) (res BgInitResponse, reterr error) {
+func background_init(ctx context.Context, client *http.Client, user_uuid string) (res BgInitResponse, reterr error) {
 	post_data := make(url.Values)
 	post_data.Add("login", "1")
 	post_data.Add("ver", EXT_VER)
 	qs := make(url.Values)
 	qs.Add("uuid", user_uuid)
-	resp, err := do_req(ctx, "POST", BG_INIT_URL, qs, post_data)
+	resp, err := do_req(ctx, client, "POST", BG_INIT_URL, qs, post_data)
 	if err != nil {
 		reterr = err
 		return
@@ -143,6 +205,7 @@ func background_init(ctx context.Context, user_uuid string) (res BgInitResponse,
 }
 
 func zgettunnels(ctx context.Context,
+	client *http.Client,
 	user_uuid string,
 	session_key int64,
 	country string,
@@ -163,14 +226,14 @@ func zgettunnels(ctx context.Context,
 		params.Add("country", country)
 	}
 	params.Add("limit", strconv.FormatInt(int64(limit), 10))
-	params.Add("ping_id", strconv.FormatFloat(rand.Float64(), 'f', -1, 64))
+	params.Add("ping_id", strconv.FormatFloat(rand.New(RandomSource).Float64(), 'f', -1, 64))
 	params.Add("ext_ver", EXT_VER)
 	params.Add("browser", EXT_BROWSER)
 	params.Add("product", PRODUCT)
 	params.Add("uuid", user_uuid)
 	params.Add("session_key", strconv.FormatInt(session_key, 10))
 	params.Add("is_premium", "0")
-	data, err := do_req(ctx, "", ZGETTUNNELS_URL, params, nil)
+	data, err := do_req(ctx, client, "", ZGETTUNNELS_URL, params, nil)
 	if err != nil {
 		reterr = err
 		return
@@ -180,17 +243,137 @@ func zgettunnels(ctx context.Context,
 	return
 }
 
+func fetchFallbackConfig(ctx context.Context) (*FallbackConfig, error) {
+	confRaw, err := do_req(ctx, &http.Client{}, "", FALLBACK_CONF_URL, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	l := len(confRaw)
+	if l < 4 {
+		return nil, errors.New("bad response length from fallback conf URL")
+	}
+
+	buf := &bytes.Buffer{}
+	buf.Grow(l)
+	buf.Write(confRaw[l-3:])
+	buf.Write(confRaw[:l-3])
+
+	b64dec := base64.NewDecoder(base64.RawStdEncoding, buf)
+	jdec := json.NewDecoder(b64dec)
+	fbc := &FallbackConfig{}
+
+	err = jdec.Decode(fbc)
+	if err != nil {
+		return nil, err
+	}
+
+	if fbc.Expired() {
+		return nil, errors.New("fetched expired fallback config")
+	}
+
+	fbc.ShuffleAgents()
+	return fbc, nil
+}
+
+var (
+	fbcMux    sync.Mutex
+	cachedFBC *FallbackConfig
+)
+
+func GetFallbackProxies(ctx context.Context) (*FallbackConfig, error) {
+	fbcMux.Lock()
+	defer fbcMux.Unlock()
+
+	var (
+		fbc *FallbackConfig
+		err error
+	)
+
+	if cachedFBC == nil || cachedFBC.Expired() {
+		fbc, err = fetchFallbackConfig(ctx)
+		if err != nil {
+			return nil, err
+		}
+		cachedFBC = fbc
+	} else {
+		fbc = cachedFBC
+	}
+
+	return fbc.Clone(), nil
+}
+
 func Tunnels(ctx context.Context,
+	client *http.Client,
 	country string,
 	proxy_type string,
 	limit uint) (res *ZGetTunnelsResponse, user_uuid string, reterr error) {
 	u := uuid.New()
 	user_uuid = hex.EncodeToString(u[:])
-	initres, err := background_init(ctx, user_uuid)
+	initres, err := background_init(ctx, client, user_uuid)
 	if err != nil {
 		reterr = err
 		return
 	}
-	res, reterr = zgettunnels(ctx, user_uuid, initres.Key, country, proxy_type, limit)
+	res, reterr = zgettunnels(ctx, client, user_uuid, initres.Key, country, proxy_type, limit)
 	return
 }
+
+// Returns default http client with a proxy override
+func httpClientWithProxy(agent *FallbackAgent) *http.Client {
+	t := &http.Transport{
+		ForceAttemptHTTP2:     true,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+	}
+	dialer := &net.Dialer{
+		Timeout:   30 * time.Second,
+		KeepAlive: 30 * time.Second,
+	}
+	if agent == nil {
+		t.DialContext = dialer.DialContext
+	} else {
+		t.Proxy = http.ProxyURL(agent.ToProxy())
+		addr := net.JoinHostPort(agent.IP, fmt.Sprintf("%d", agent.Port))
+		t.DialContext = func(ctx context.Context, _, _ string) (net.Conn, error) {
+			return dialer.DialContext(ctx, "tcp4", addr)
+		}
+	}
+	return &http.Client{
+		Transport: t,
+	}
+}
+
+func EnsureTransaction(baseCtx context.Context, txnTimeout time.Duration, txn func(context.Context, *http.Client) bool) (bool, error) {
+	client := httpClientWithProxy(nil)
+	defer client.CloseIdleConnections()
+
+	ctx, cancel := context.WithTimeout(baseCtx, txnTimeout)
+	defer cancel()
+
+	if txn(ctx, client) {
+		return true, nil
+	}
+
+	// Fallback needed
+	fbc, err := GetFallbackProxies(baseCtx)
+	if err != nil {
+		return false, err
+	}
+
+	for _, agent := range fbc.Agents {
+		client = httpClientWithProxy(&agent)
+		defer client.CloseIdleConnections()
+
+		ctx, cancel = context.WithTimeout(baseCtx, txnTimeout)
+		defer cancel()
+
+		if txn(ctx, client) {
+			return true, nil
+		}
+	}
+
+	return false, nil
+}

hooks/build

@@ -0,0 +1,2 @@
+#!/bin/bash
+docker build --build-arg GIT_DESC="$(git describe)" -f "$DOCKERFILE_PATH" -t "$IMAGE_NAME" .

main.go

@@ -13,6 +13,7 @@ import (
 
 var (
 	PROTOCOL_WHITELIST map[string]bool
+	version            = "undefined"
 )
 
 func init() {
@@ -44,6 +45,7 @@ type CLIArgs struct {
 	proxy_type                              string
 	resolver                                string
 	force_port_field                        string
+	showVersion                             bool
 }
 
 func parse_args() CLIArgs {
@@ -64,6 +66,7 @@ func parse_args() CLIArgs {
 		"DNS/DoH/DoT resolver to workaround Hola blocked hosts. "+
 			"See https://github.com/ameshkov/dnslookup/ for upstream DNS URL format.")
 	flag.BoolVar(&args.use_trial, "dont-use-trial", false, "use regular ports instead of trial ports") // would be nice to not show in help page
+	flag.BoolVar(&args.showVersion, "version", false, "show program version and exit")
 	flag.Parse()
 	if args.country == "" {
 		arg_fail("Country can't be empty string.")
@@ -79,6 +82,11 @@ func parse_args() CLIArgs {
 
 func run() int {
 	args := parse_args()
+	if args.showVersion {
+		fmt.Println(version)
+		return 0
+	}
+
 	if args.list_countries {
 		return print_countries(args.timeout)
 	}
@@ -98,6 +106,7 @@ func run() int {
 	proxyLogger := NewCondLogger(log.New(logWriter, "PROXY   : ",
 		log.LstdFlags|log.Lshortfile),
 		args.verbosity)
+	mainLogger.Info("hola-proxy client version %s is starting...", version)
 	mainLogger.Info("Constructing fallback DNS upstream...")
 	resolver, err := NewResolver(args.resolver, args.timeout)
 	if err != nil {
@@ -120,6 +129,7 @@ func run() int {
 	mainLogger.Info("Endpoint: %s", endpoint)
 	mainLogger.Info("Starting proxy server...")
 	handler := NewProxyHandler(endpoint, auth, resolver, proxyLogger)
+	mainLogger.Info("Init complete.")
 	err = http.ListenAndServe(args.bind_address, handler)
 	mainLogger.Critical("Server terminated with a reason: %v", err)
 	mainLogger.Info("Shutting down...")

snapcraft.yaml

@@ -1,5 +1,5 @@
 name: hola-proxy
-version: '1.4.2'
+version: '1.4.4'
 summary: Standalone Hola proxy client.
 description: |
   Standalone Hola proxy client. Just run it and it'll start plain HTTP proxy server forwarding traffic via Hola proxies of your choice.
@@ -10,15 +10,18 @@ base: core18
 parts:
   hola-proxy:
     plugin: go
-    go-importpath: github.com/Snawoot/hola-proxy
-    source: https://github.com/Snawoot/hola-proxy
-    source-type: git
+    source: .
     build-packages:
       - gcc
+    override-build:
+      make &&
+      cp bin/hola-proxy "$SNAPCRAFT_PART_INSTALL"
+    stage:
+      - hola-proxy
 
 apps:
   hola-proxy:
-    command: bin/hola-proxy
+    command: hola-proxy
     plugs:
       - network
       - network-bind

utils.go

@@ -50,10 +50,24 @@ func proxy(ctx context.Context, left, right net.Conn) {
 }
 
 func print_countries(timeout time.Duration) int {
-	ctx, _ := context.WithTimeout(context.Background(), timeout)
-	countries, err := VPNCountries(ctx)
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+	var (
+		countries CountryList
+		err       error
+	)
+	tx_res, tx_err := EnsureTransaction(context.Background(), timeout, func(ctx context.Context, client *http.Client) bool {
+		countries, err = VPNCountries(ctx, client)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Transaction error: %v. Retrying with the fallback mechanism...\n", err)
+			return false
+		}
+		return true
+	})
+	if tx_err != nil {
+		fmt.Fprintf(os.Stderr, "Transaction recovery mechanism failure: %v.\n", tx_err)
+		return 4
+	}
+	if !tx_res {
+		fmt.Fprintf(os.Stderr, "All attempts failed.")
 		return 3
 	}
 	for _, code := range countries {
@@ -63,10 +77,25 @@ func print_countries(timeout time.Duration) int {
 }
 
 func print_proxies(country string, proxy_type string, limit uint, timeout time.Duration) int {
-	ctx, _ := context.WithTimeout(context.Background(), timeout)
-	tunnels, user_uuid, err := Tunnels(ctx, country, proxy_type, limit)
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+	var (
+		tunnels   *ZGetTunnelsResponse
+		user_uuid string
+		err       error
+	)
+	tx_res, tx_err := EnsureTransaction(context.Background(), timeout, func(ctx context.Context, client *http.Client) bool {
+		tunnels, user_uuid, err = Tunnels(ctx, client, country, proxy_type, limit)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Transaction error: %v. Retrying with the fallback mechanism...\n", err)
+			return false
+		}
+		return true
+	})
+	if tx_err != nil {
+		fmt.Fprintf(os.Stderr, "Transaction recovery mechanism failure: %v.\n", tx_err)
+		return 4
+	}
+	if !tx_res {
+		fmt.Fprintf(os.Stderr, "All attempts failed.")
 		return 3
 	}
 	wr := csv.NewWriter(os.Stdout)