bump snap version

Major network stack rework

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

@@ -3,14 +3,19 @@ OUTSUFFIX = bin/$(PROGNAME)
 VERSION := $(shell git describe)
 BUILDOPTS = -a -tags netgo
 LDFLAGS = -ldflags '-s -w -extldflags "-static" -X main.version=$(VERSION)'
+LDFLAGS_NATIVE = -ldflags '-s -w -X main.version=$(VERSION)'
+
+GO := go
 
 src = $(wildcard *.go)
 
 native: bin-native
 all: bin-linux-amd64 bin-linux-386 bin-linux-arm \
 	bin-freebsd-amd64 bin-freebsd-386 bin-freebsd-arm \
-	bin-darwin-amd64 \
-	bin-windows-amd64 bin-windows-386
+	bin-netbsd-amd64 bin-netbsd-386 \
+	bin-openbsd-amd64 bin-openbsd-386 \
+	bin-darwin-amd64 bin-darwin-arm64 \
+	bin-windows-amd64 bin-windows-386 bin-windows-arm
 
 bin-native: $(OUTSUFFIX)
 bin-linux-amd64: $(OUTSUFFIX).linux-amd64
@@ -19,51 +24,75 @@ bin-linux-arm: $(OUTSUFFIX).linux-arm
 bin-freebsd-amd64: $(OUTSUFFIX).freebsd-amd64
 bin-freebsd-386: $(OUTSUFFIX).freebsd-386
 bin-freebsd-arm: $(OUTSUFFIX).freebsd-arm
+bin-netbsd-amd64: $(OUTSUFFIX).netbsd-amd64
+bin-netbsd-386: $(OUTSUFFIX).netbsd-386
+bin-openbsd-amd64: $(OUTSUFFIX).openbsd-amd64
+bin-openbsd-386: $(OUTSUFFIX).openbsd-386
 bin-darwin-amd64: $(OUTSUFFIX).darwin-amd64
+bin-darwin-arm64: $(OUTSUFFIX).darwin-arm64
 bin-windows-amd64: $(OUTSUFFIX).windows-amd64.exe
 bin-windows-386: $(OUTSUFFIX).windows-386.exe
+bin-windows-arm: $(OUTSUFFIX).windows-arm.exe
 
 $(OUTSUFFIX): $(src)
-	CGO_ENABLED=0 go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	$(GO) build $(LDFLAGS_NATIVE) -o $@
 
 $(OUTSUFFIX).linux-amd64: $(src)
-	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
 
 $(OUTSUFFIX).linux-386: $(src)
-	CGO_ENABLED=0 GOOS=linux GOARCH=386 go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	CGO_ENABLED=0 GOOS=linux GOARCH=386 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
 
 $(OUTSUFFIX).linux-arm: $(src)
-	CGO_ENABLED=0 GOOS=linux GOARCH=arm go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	CGO_ENABLED=0 GOOS=linux GOARCH=arm $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
 
 $(OUTSUFFIX).freebsd-amd64: $(src)
-	CGO_ENABLED=0 GOOS=freebsd GOARCH=amd64 go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	CGO_ENABLED=0 GOOS=freebsd GOARCH=amd64 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
 
 $(OUTSUFFIX).freebsd-386: $(src)
-	CGO_ENABLED=0 GOOS=freebsd GOARCH=386 go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	CGO_ENABLED=0 GOOS=freebsd GOARCH=386 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
 
 $(OUTSUFFIX).freebsd-arm: $(src)
-	CGO_ENABLED=0 GOOS=freebsd GOARCH=arm go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	CGO_ENABLED=0 GOOS=freebsd GOARCH=arm $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
+
+$(OUTSUFFIX).netbsd-amd64: $(src)
+	CGO_ENABLED=0 GOOS=netbsd GOARCH=amd64 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
+
+$(OUTSUFFIX).netbsd-386: $(src)
+	CGO_ENABLED=0 GOOS=netbsd GOARCH=386 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
+
+$(OUTSUFFIX).openbsd-amd64: $(src)
+	CGO_ENABLED=0 GOOS=openbsd GOARCH=amd64 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
+
+$(OUTSUFFIX).openbsd-386: $(src)
+	CGO_ENABLED=0 GOOS=openbsd GOARCH=386 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
 
 $(OUTSUFFIX).darwin-amd64: $(src)
-	CGO_ENABLED=0 GOOS=darwin GOARCH=amd64 go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	CGO_ENABLED=0 GOOS=darwin GOARCH=amd64 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
+
+$(OUTSUFFIX).darwin-arm64: $(src)
+	CGO_ENABLED=0 GOOS=darwin GOARCH=arm64 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
 
 $(OUTSUFFIX).windows-amd64.exe: $(src)
-	CGO_ENABLED=0 GOOS=windows GOARCH=amd64 go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	CGO_ENABLED=0 GOOS=windows GOARCH=amd64 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
 
 $(OUTSUFFIX).windows-386.exe: $(src)
-	CGO_ENABLED=0 GOOS=windows GOARCH=386 go build $(BUILDOPTS) $(LDFLAGS) -o $@
+	CGO_ENABLED=0 GOOS=windows GOARCH=386 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
+
+$(OUTSUFFIX).windows-arm.exe: $(src)
+	CGO_ENABLED=0 GOOS=windows GOARCH=arm GOARM=7 $(GO) build $(BUILDOPTS) $(LDFLAGS) -o $@
 
 clean:
 	rm -f bin/*
 
 fmt:
-	go fmt ./...
+	$(GO) fmt ./...
 
 run:
-	go run $(LDFLAGS) .
+	$(GO) run $(LDFLAGS) .
 
 install:
-	go install $(BUILDOPTS) $(LDFLAGS) .
+	$(GO) install $(LDFLAGS_NATIVE) .
 
 .PHONY: clean all native fmt install \
 	bin-native \

README.md

@@ -2,7 +2,8 @@
 
 [![hola-proxy](https://snapcraft.io//hola-proxy/badge.svg)](https://snapcraft.io/hola-proxy)
 
-Standalone Hola proxy client. Just run it and it'll start plain HTTP proxy server forwarding traffic via Hola proxies of your choice. By default application listens port on 127.0.0.1:8080.
+Standalone Hola proxy client. Just run it and it'll start a plain HTTP proxy server forwarding traffic through Hola proxies of your choice.
+By default the application listens on 127.0.0.1:8080.
 
 Application is capable to forward traffic via proxies in datacenters (flag `-proxy-type direct`, default) or via peer proxies on residental IPs (consumer ISP) in that country (flag `-proxy-type pool` or `-proxy-type lum`).
 
@@ -31,17 +32,18 @@ git clone https://ipfs.io/ipns/k51qzi5uqu5dkrgx0hozpy1tlggw5o0whtquyrjlc6pprhvbm
 
 * Cross-platform (Windows/Mac OS/Linux/Android (via shell)/\*BSD)
 * Uses TLS for secure communication with upstream proxies
-* Zero-configuration
+* Zero configuration
+* Simple and straight forward
 
 ## Installation
 
-#### Binary download
+#### Binaries
 
-Pre-built binaries available on [releases](https://github.com/Snawoot/hola-proxy/releases/latest) page.
+Pre-built binaries are available [here](https://github.com/Snawoot/hola-proxy/releases/latest).
 
-#### From source
+#### Build from source
 
-Alternatively, you may install hola-proxy from source. Run within source directory
+Alternatively, you may install hola-proxy from source. Run the following within the source directory:
 
 ```
 make install
@@ -49,7 +51,7 @@ make install
 
 #### Docker
 
-Docker image is available as well. Here is an example for running proxy via DE as a background service:
+A docker image is available as well. Here is an example of running hola-proxy via DE as a background service:
 
 ```sh
 docker run -d \
@@ -73,7 +75,7 @@ sudo snap install hola-proxy
 List available countries:
 
 ```
-$ ~/go/bin/hola-proxy -list-countries
+$ ./hola-proxy -list-countries
 ar - Argentina
 at - Austria
 au - Australia
@@ -121,19 +123,19 @@ us - United States of America
 Run proxy via country of your choice:
 
 ```
-$ ~/go/bin/hola-proxy -country de
+$ ./hola-proxy -country de
 ```
 
-Or run proxy on residental IP:
+Or run proxy on residential IP:
 
 ```
-$ ~/go/bin/hola-proxy -country de -proxy-type lum
+$ ./hola-proxy -proxy-type lum
 ```
 
 Also it is possible to export proxy addresses and credentials:
 
 ```
-$ ~/go/bin/hola-proxy -country de -list-proxies -limit 3
+$ ./hola-proxy -country de -list-proxies -limit 3
 Login: user-uuid-0a67c797b3214cbdb432b089c4b801cd
 Password: cd123c465901
 Proxy-Authorization: basic dXNlci11dWlkLTBhNjdjNzk3YjMyMTRjYmRiNDMyYjA4OWM0YjgwMWNkOmNkMTIzYzQ2NTkwMQ==
@@ -144,33 +146,19 @@ zagent830.hola.org,104.248.24.64,22222,22223,22224,22225,22226,digitalocean
 zagent248.hola.org,165.22.65.3,22222,22223,22224,22225,22226,digitalocean
 ```
 
-## Synopsis
+## List of arguments
 
-```
-$ ~/go/bin/hola-proxy -h
-Usage of /home/user/go/bin/hola-proxy:
-  -bind-address string
-    	HTTP proxy listen address (default "127.0.0.1:8080")
-  -country string
-    	desired proxy location (default "us")
-  -dont-use-trial
-    	use regular ports instead of trial ports
-  -force-port-field string
-    	force specific port field/num (example 24232 or lum)
-  -limit uint
-    	amount of proxies in retrieved list (default 3)
-  -list-countries
-    	list available countries and exit
-  -list-proxies
-    	output proxy list and exit
-  -proxy-type string
-    	proxy type: direct or peer or lum or virt or pool (default "direct")
-  -resolver string
-    	DNS/DoH/DoT resolver to workaround Hola blocked hosts. See https://github.com/ameshkov/dnslookup/ for upstream DNS URL format. (default "https://cloudflare-dns.com/dns-query")
-  -rotate duration
-    	rotate user ID once per given period (default 1h0m0s)
-  -timeout duration
-    	timeout for network operations (default 10s)
-  -verbosity int
-    	logging verbosity (10 - debug, 20 - info, 30 - warning, 40 - error, 50 - critical) (default 20)
-```
+| Argument | Type | Description |
+| -------- | ---- | ----------- |
+| bind-address | String | HTTP proxy address to listen to (default "127.0.0.1:8080") |
+| country | String | desired proxy location (default "us") |
+| dont-use-trial | - | use regular ports instead of trial ports |
+| force-port-field | Number | force specific port field/num (example 24232 or lum) |
+| limit | Unsigned Integer (Number) | amount of proxies in retrieved list (default 3) |
+| list-countries | String | list available countries and exit |
+| list-proxies | - | output proxy list and exit |
+| proxy-type | String | proxy type (Datacenter: direct, virt) (Residential: peer, lum, pool) (default "direct") |
+| resolver | String | DNS/DoH/DoT resolver to workaround Hola blocked hosts. See https://github.com/ameshkov/dnslookup/ for upstream DNS URL format. (default "https://cloudflare-dns.com/dns-query") |
+| rotate | Duration | rotate user ID once per given period (default 1h0m0s) |
+| timeout | Duration | timeout for network operations (default 10s) |
+| verbosity | Number | logging verbosity (10 - debug, 20 - info, 30 - warning, 40 - error, 50 - critical) (default 20) |

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()
+}

handler.go

@@ -1,122 +1,48 @@
 package main
 
 import (
-	"bufio"
-	"crypto/tls"
-	"io"
+	"fmt"
 	"net/http"
-	"net/http/httputil"
-	"net/url"
 	"strings"
+	"time"
 )
 
+const BAD_REQ_MSG = "Bad Request\n"
+
 type AuthProvider func() string
 
 type ProxyHandler struct {
-	auth          AuthProvider
-	upstream      string
 	logger        *CondLogger
+	dialer        ContextDialer
 	httptransport http.RoundTripper
-	resolver      *Resolver
 }
 
-func NewProxyHandler(upstream string, auth AuthProvider, resolver *Resolver, logger *CondLogger) *ProxyHandler {
-	proxyurl, err := url.Parse("https://" + upstream)
-	if err != nil {
-		panic(err)
-	}
+func NewProxyHandler(dialer ContextDialer, resolver *Resolver, logger *CondLogger) *ProxyHandler {
+	dialer = NewRetryDialer(dialer, resolver, logger)
 	httptransport := &http.Transport{
-		Proxy: http.ProxyURL(proxyurl),
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+		DialContext:           dialer.DialContext,
 	}
 	return &ProxyHandler{
-		auth:          auth,
-		upstream:      upstream,
 		logger:        logger,
+		dialer:        dialer,
 		httptransport: httptransport,
-		resolver:      resolver,
 	}
 }
 
-func (s *ProxyHandler) ServeHTTP(wr http.ResponseWriter, req *http.Request) {
-	s.logger.Info("Request: %v %v %v", req.RemoteAddr, req.Method, req.URL)
-	if strings.ToUpper(req.Method) == "CONNECT" {
-		req.Header.Set("Proxy-Authorization", s.auth())
-		rawreq, err := httputil.DumpRequest(req, false)
-		if err != nil {
-			s.logger.Error("Can't dump request: %v", err)
-			http.Error(wr, "Can't dump request", http.StatusInternalServerError)
-			return
-		}
-
-		conn, err := tls.Dial("tcp", s.upstream, nil)
-		if err != nil {
-			s.logger.Error("Can't dial tls upstream: %v", err)
-			http.Error(wr, "Can't dial tls upstream", http.StatusBadGateway)
-			return
-		}
-
-		_, err = conn.Write(rawreq)
-		if err != nil {
-			s.logger.Error("Can't write tls upstream: %v", err)
-			http.Error(wr, "Can't write tls upstream", http.StatusBadGateway)
-			return
-		}
-		bufrd := bufio.NewReader(conn)
-		proxyResp, err := http.ReadResponse(bufrd, req)
-		responseBytes := make([]byte, 0)
-		if err != nil {
-			s.logger.Error("Can't read response from upstream: %v", err)
-			http.Error(wr, "Can't read response from upstream", http.StatusBadGateway)
-			return
-		}
-
-		if proxyResp.StatusCode == http.StatusForbidden &&
-			proxyResp.Header.Get("X-Hola-Error") == "Forbidden Host" {
-			s.logger.Info("Request %s denied by upstream. Rescuing it with resolve&rewrite workaround.",
-				req.URL.String())
-			conn.Close()
-			conn, err = tls.Dial("tcp", s.upstream, nil)
-			if err != nil {
-				s.logger.Error("Can't dial tls upstream: %v", err)
-				http.Error(wr, "Can't dial tls upstream", http.StatusBadGateway)
-				return
-			}
-			defer conn.Close()
-			err = rewriteConnectReq(req, s.resolver)
-			if err != nil {
-				s.logger.Error("Can't rewrite request: %v", err)
-				http.Error(wr, "Can't rewrite request", http.StatusInternalServerError)
-				return
-			}
-			rawreq, err = httputil.DumpRequest(req, false)
-			if err != nil {
-				s.logger.Error("Can't dump request: %v", err)
-				http.Error(wr, "Can't dump request", http.StatusInternalServerError)
-				return
-			}
-			_, err = conn.Write(rawreq)
-			if err != nil {
-				s.logger.Error("Can't write tls upstream: %v", err)
-				http.Error(wr, "Can't write tls upstream", http.StatusBadGateway)
-				return
-			}
-		} else {
-			defer conn.Close()
-			responseBytes, err = httputil.DumpResponse(proxyResp, false)
-			if err != nil {
-				s.logger.Error("Can't dump response: %v", err)
-				http.Error(wr, "Can't dump response", http.StatusInternalServerError)
-				return
-			}
-			buffered := bufrd.Buffered()
-			if buffered > 0 {
-				trailer := make([]byte, buffered)
-				bufrd.Read(trailer)
-				responseBytes = append(responseBytes, trailer...)
-			}
-		}
-		bufrd = nil
+func (s *ProxyHandler) HandleTunnel(wr http.ResponseWriter, req *http.Request) {
+	ctx := req.Context()
+	conn, err := s.dialer.DialContext(ctx, "tcp", req.RequestURI)
+	if err != nil {
+		s.logger.Error("Can't satisfy CONNECT request: %v", err)
+		http.Error(wr, "Can't satisfy CONNECT request", http.StatusBadGateway)
+		return
+	}
 
+	if req.ProtoMajor == 0 || req.ProtoMajor == 1 {
 		// Upgrade client connection
 		localconn, _, err := hijack(wr)
 		if err != nil {
@@ -126,95 +52,56 @@ func (s *ProxyHandler) ServeHTTP(wr http.ResponseWriter, req *http.Request) {
 		}
 		defer localconn.Close()
 
-		if len(responseBytes) > 0 {
-			_, err = localconn.Write(responseBytes)
-			if err != nil {
-				return
-			}
-		}
+		// Inform client connection is built
+		fmt.Fprintf(localconn, "HTTP/%d.%d 200 OK\r\n\r\n", req.ProtoMajor, req.ProtoMinor)
+
 		proxy(req.Context(), localconn, conn)
+	} else if req.ProtoMajor == 2 {
+		wr.Header()["Date"] = nil
+		wr.WriteHeader(http.StatusOK)
+		flush(wr)
+		proxyh2(req.Context(), req.Body, wr, conn)
 	} else {
-		delHopHeaders(req.Header)
-		orig_req := req.Clone(req.Context())
-		req.RequestURI = ""
-		req.Header.Set("Proxy-Authorization", s.auth())
-		resp, err := s.httptransport.RoundTrip(req)
-		if err != nil {
-			s.logger.Error("HTTP fetch error: %v", err)
-			http.Error(wr, "Server Error", http.StatusInternalServerError)
-			return
-		}
-		if resp.StatusCode == http.StatusForbidden &&
-			resp.Header.Get("X-Hola-Error") == "Forbidden Host" {
-			s.logger.Info("Request %s denied by upstream. Rescuing it with resolve&tunnel workaround.",
-				req.URL.String())
-			resp.Body.Close()
-
-			// Prepare tunnel request
-			proxyReq, err := makeConnReq(orig_req.RequestURI, s.resolver)
-			if err != nil {
-				s.logger.Error("Can't rewrite request: %v", err)
-				http.Error(wr, "Can't rewrite request", http.StatusBadGateway)
-				return
-			}
-			proxyReq.Header.Set("Proxy-Authorization", s.auth())
-			rawreq, _ := httputil.DumpRequest(proxyReq, false)
-
-			// Prepare upstream TLS conn
-			conn, err := tls.Dial("tcp", s.upstream, nil)
-			if err != nil {
-				s.logger.Error("Can't dial tls upstream: %v", err)
-				http.Error(wr, "Can't dial tls upstream", http.StatusBadGateway)
-				return
-			}
-			defer conn.Close()
-
-			// Send proxy request
-			_, err = conn.Write(rawreq)
-			if err != nil {
-				s.logger.Error("Can't write tls upstream: %v", err)
-				http.Error(wr, "Can't write tls upstream", http.StatusBadGateway)
-				return
-			}
-
-			// Read proxy response
-			bufrd := bufio.NewReader(conn)
-			proxyResp, err := http.ReadResponse(bufrd, proxyReq)
-			if err != nil {
-				s.logger.Error("Can't read response from upstream: %v", err)
-				http.Error(wr, "Can't read response from upstream", http.StatusBadGateway)
-				return
-			}
-			if proxyResp.StatusCode != http.StatusOK {
-				delHopHeaders(proxyResp.Header)
-				copyHeader(wr.Header(), proxyResp.Header)
-				wr.WriteHeader(proxyResp.StatusCode)
-			}
-
-			// Send tunneled request
-			orig_req.RequestURI = ""
-			orig_req.Header.Set("Connection", "close")
-			rawreq, _ = httputil.DumpRequest(orig_req, false)
-			_, err = conn.Write(rawreq)
-			if err != nil {
-				s.logger.Error("Can't write tls upstream: %v", err)
-				http.Error(wr, "Can't write tls upstream", http.StatusBadGateway)
-				return
-			}
-
-			// Read tunneled response
-			resp, err = http.ReadResponse(bufrd, orig_req)
-			if err != nil {
-				s.logger.Error("Can't read response from upstream: %v", err)
-				http.Error(wr, "Can't read response from upstream", http.StatusBadGateway)
-				return
-			}
-		}
-		defer resp.Body.Close()
-		s.logger.Info("%v %v %v %v", req.RemoteAddr, req.Method, req.URL, resp.Status)
-		delHopHeaders(resp.Header)
-		copyHeader(wr.Header(), resp.Header)
-		wr.WriteHeader(resp.StatusCode)
-		io.Copy(wr, resp.Body)
+		s.logger.Error("Unsupported protocol version: %s", req.Proto)
+		http.Error(wr, "Unsupported protocol version.", http.StatusBadRequest)
+		return
+	}
+}
+
+func (s *ProxyHandler) HandleRequest(wr http.ResponseWriter, req *http.Request) {
+	req.RequestURI = ""
+	if req.ProtoMajor == 2 {
+		req.URL.Scheme = "http" // We can't access :scheme pseudo-header, so assume http
+		req.URL.Host = req.Host
+	}
+	resp, err := s.httptransport.RoundTrip(req)
+	if err != nil {
+		s.logger.Error("HTTP fetch error: %v", err)
+		http.Error(wr, "Server Error", http.StatusInternalServerError)
+		return
+	}
+	defer resp.Body.Close()
+	s.logger.Info("%v %v %v %v", req.RemoteAddr, req.Method, req.URL, resp.Status)
+	delHopHeaders(resp.Header)
+	copyHeader(wr.Header(), resp.Header)
+	wr.WriteHeader(resp.StatusCode)
+	flush(wr)
+	copyBody(wr, resp.Body)
+}
+
+func (s *ProxyHandler) ServeHTTP(wr http.ResponseWriter, req *http.Request) {
+	s.logger.Info("Request: %v %v %v %v", req.RemoteAddr, req.Proto, req.Method, req.URL)
+
+	isConnect := strings.ToUpper(req.Method) == "CONNECT"
+	if (req.URL.Host == "" || req.URL.Scheme == "" && !isConnect) && req.ProtoMajor < 2 ||
+		req.Host == "" && req.ProtoMajor == 2 {
+		http.Error(wr, BAD_REQ_MSG, http.StatusBadRequest)
+		return
+	}
+	delHopHeaders(req.Header)
+	if isConnect {
+		s.HandleTunnel(wr, req)
+	} else {
+		s.HandleRequest(wr, req)
 	}
 }

helper.sh

@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+
+# arguments <country> <proxytype(default direct, needs explicit country)> <port(default autogen using country+proxytype, needs explicit proxytype)>
+country=${1-us}
+proxytype=${2-direct}
+
+if [ -z "$3" ]
+then
+	port=17160
+	for x in {a..z}{a..z} # loop over all possible country codes (676 possibilities)
+	do
+		port=$((port+1))
+		if [ "$x" == "$country" ]
+		then
+			true
+			break
+		else
+			false
+		fi
+	done || { echo "country code $country is invalid" >&2; exit 1;}
+
+	case $proxytype in # port range = 17160+1 -> 17160+676*5
+		direct) port=$((676*0+port))                     ;;
+		peer)   port=$((676*1+port))                     ;;
+		lum)    port=$((676*2+port))                     ;;
+		virt)   port=$((676*3+port))                     ;;
+		pool)   port=$((676*4+port))                     ;;
+		*)      echo "proxy-type $proxytype invalid" >&2
+                        exit 1                                   ;;
+	esac
+else
+	port=$3
+fi
+
+try_binary() {
+	for x in "${@}"
+	do
+		type -a "$x" >/dev/null 2>&1 && { echo "$x"; return 0; } || false
+	done || return 1
+}
+
+binary=$(try_binary "hola-proxy" "$HOME/go/bin/hola-proxy")
+if [ -n "$binary" ]
+then
+	echo "country    $country"
+	echo "proxytype  $proxytype"
+	echo "proxy      127.0.0.1:$port"
+	echo
+	exec "$binary" -bind-address "127.0.0.1:$port" -country "$country" -proxy-type "$proxytype" -verbosity 50
+else
+	echo "hola-proxy binary cannot be found" >&2
+	exit 1
+fi

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 +64,74 @@ 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 (a *FallbackAgent) Hostname() string {
+	return a.Name + AGENT_SUFFIX
+}
+
+func (a *FallbackAgent) NetAddr() string {
+	return net.JoinHostPort(a.IP, 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"
@@ -101,10 +171,10 @@ 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 +189,13 @@ 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 +213,7 @@ 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 +234,14 @@ 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 +251,132 @@ 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,
+	}
+	var dialer ContextDialer = &net.Dialer{
+		Timeout:   30 * time.Second,
+		KeepAlive: 30 * time.Second,
+	}
+	if agent != nil {
+		dialer = NewProxyDialer(agent.NetAddr(), agent.Hostname(), nil, dialer)
+	}
+	t.DialContext = dialer.DialContext
+	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

@@ -4,10 +4,9 @@ import (
 	"flag"
 	"fmt"
 	"log"
-	"os"
-	//    "os/signal"
-	//    "syscall"
+	"net"
 	"net/http"
+	"os"
 	"time"
 )
 
@@ -126,9 +125,13 @@ func run() int {
 		logWriter.Close()
 		return 5
 	}
-	mainLogger.Info("Endpoint: %s", endpoint)
+	var dialer ContextDialer = NewProxyDialer(endpoint.NetAddr(), endpoint.TLSName, auth, &net.Dialer{
+		Timeout:   30 * time.Second,
+		KeepAlive: 30 * time.Second,
+	})
+	mainLogger.Info("Endpoint: %s", endpoint.URL().String())
 	mainLogger.Info("Starting proxy server...")
-	handler := NewProxyHandler(endpoint, auth, resolver, proxyLogger)
+	handler := NewProxyHandler(dialer, resolver, proxyLogger)
 	mainLogger.Info("Init complete.")
 	err = http.ListenAndServe(args.bind_address, handler)
 	mainLogger.Critical("Server terminated with a reason: %v", err)

retry.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"context"
+	"net"
+)
+
+type RetryDialer struct {
+	dialer   ContextDialer
+	resolver *Resolver
+	logger   *CondLogger
+}
+
+func NewRetryDialer(dialer ContextDialer, resolver *Resolver, logger *CondLogger) *RetryDialer {
+	return &RetryDialer{
+		dialer:   dialer,
+		resolver: resolver,
+		logger:   logger,
+	}
+}
+
+func (d *RetryDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	conn, err := d.dialer.DialContext(ctx, network, address)
+	if err == UpstreamBlockedError {
+		d.logger.Info("Destination %s blocked by upstream. Rescuing it with resolve&tunnel workaround.", address)
+		host, port, err1 := net.SplitHostPort(address)
+		if err1 != nil {
+			return conn, err
+		}
+
+		ips := d.resolver.Resolve(host)
+		if len(ips) == 0 {
+			return conn, err
+		}
+
+		return d.dialer.DialContext(ctx, network, net.JoinHostPort(ips[0], port))
+	}
+	return conn, err
+}

snapcraft.yaml

@@ -1,5 +1,5 @@
 name: hola-proxy
-version: '1.4.2'
+version: '1.4.6'
 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

upstream.go

@@ -0,0 +1,144 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httputil"
+)
+
+const (
+	PROXY_CONNECT_METHOD       = "CONNECT"
+	PROXY_HOST_HEADER          = "Host"
+	PROXY_AUTHORIZATION_HEADER = "Proxy-Authorization"
+)
+
+var UpstreamBlockedError = errors.New("blocked by upstream")
+
+type ContextDialer interface {
+	DialContext(ctx context.Context, network, address string) (net.Conn, error)
+}
+
+type ProxyDialer struct {
+	address       string
+	tlsServerName string
+	auth          AuthProvider
+	next          ContextDialer
+}
+
+func NewProxyDialer(address, tlsServerName string, auth AuthProvider, nextDialer ContextDialer) *ProxyDialer {
+	return &ProxyDialer{
+		address:       address,
+		tlsServerName: tlsServerName,
+		auth:          auth,
+		next:          nextDialer,
+	}
+}
+
+func (d *ProxyDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	switch network {
+	case "tcp", "tcp4", "tcp6":
+	default:
+		return nil, errors.New("bad network specified for DialContext: only tcp is supported")
+	}
+
+	conn, err := d.next.DialContext(ctx, "tcp", d.address)
+	if err != nil {
+		return nil, err
+	}
+
+	if d.tlsServerName != "" {
+		// Custom cert verification logic:
+		// DO NOT send SNI extension of TLS ClientHello
+		// DO peer certificate verification against specified servername
+		conn = tls.Client(conn, &tls.Config{
+			ServerName:         "",
+			InsecureSkipVerify: true,
+			VerifyConnection: func(cs tls.ConnectionState) error {
+				opts := x509.VerifyOptions{
+					DNSName:       d.tlsServerName,
+					Intermediates: x509.NewCertPool(),
+				}
+				for _, cert := range cs.PeerCertificates[1:] {
+					opts.Intermediates.AddCert(cert)
+				}
+				_, err := cs.PeerCertificates[0].Verify(opts)
+				return err
+			},
+		})
+	}
+
+	req := &http.Request{
+		Method:     PROXY_CONNECT_METHOD,
+		Proto:      "HTTP/1.1",
+		ProtoMajor: 1,
+		ProtoMinor: 1,
+		RequestURI: address,
+		Host:       address,
+		Header: http.Header{
+			PROXY_HOST_HEADER: []string{address},
+		},
+	}
+
+	if d.auth != nil {
+		req.Header.Set(PROXY_AUTHORIZATION_HEADER, d.auth())
+	}
+
+	rawreq, err := httputil.DumpRequest(req, false)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = conn.Write(rawreq)
+	if err != nil {
+		return nil, err
+	}
+
+	proxyResp, err := readResponse(conn, req)
+	if err != nil {
+		return nil, err
+	}
+
+	if proxyResp.StatusCode != http.StatusOK {
+		if proxyResp.StatusCode == http.StatusForbidden &&
+			proxyResp.Header.Get("X-Hola-Error") == "Forbidden Host" {
+			return nil, UpstreamBlockedError
+		}
+		return nil, errors.New("Bad response from upstream proxy server")
+	}
+
+	return conn, nil
+}
+
+func readResponse(r io.Reader, req *http.Request) (*http.Response, error) {
+	endOfResponse := []byte("\r\n\r\n")
+	buf := &bytes.Buffer{}
+	b := make([]byte, 1)
+	for {
+		n, err := r.Read(b)
+		if n < 1 && err == nil {
+			continue
+		}
+
+		buf.Write(b)
+		sl := buf.Bytes()
+		if len(sl) < len(endOfResponse) {
+			continue
+		}
+
+		if bytes.Equal(sl[len(sl)-4:], endOfResponse) {
+			break
+		}
+
+		if err != nil {
+			return nil, err
+		}
+	}
+	return http.ReadResponse(bufio.NewReader(buf), req)
+}

utils.go

@@ -18,6 +18,32 @@ import (
 	"time"
 )
 
+const COPY_BUF = 128 * 1024
+
+type Endpoint struct {
+	Host    string
+	Port    uint16
+	TLSName string
+}
+
+func (e *Endpoint) URL() *url.URL {
+	if e.TLSName == "" {
+		return &url.URL{
+			Scheme: "http",
+			Host:   net.JoinHostPort(e.Host, fmt.Sprintf("%d", e.Port)),
+		}
+	} else {
+		return &url.URL{
+			Scheme: "https",
+			Host:   net.JoinHostPort(e.TLSName, fmt.Sprintf("%d", e.Port)),
+		}
+	}
+}
+
+func (e *Endpoint) NetAddr() string {
+	return net.JoinHostPort(e.Host, fmt.Sprintf("%d", e.Port))
+}
+
 func basic_auth_header(login, password string) string {
 	return "basic " + base64.StdEncoding.EncodeToString(
 		[]byte(login+":"+password))
@@ -49,11 +75,55 @@ func proxy(ctx context.Context, left, right net.Conn) {
 	return
 }
 
+func proxyh2(ctx context.Context, leftreader io.ReadCloser, leftwriter io.Writer, right net.Conn) {
+	wg := sync.WaitGroup{}
+	ltr := func(dst net.Conn, src io.Reader) {
+		defer wg.Done()
+		io.Copy(dst, src)
+		dst.Close()
+	}
+	rtl := func(dst io.Writer, src io.Reader) {
+		defer wg.Done()
+		copyBody(dst, src)
+	}
+	wg.Add(2)
+	go ltr(right, leftreader)
+	go rtl(leftwriter, right)
+	groupdone := make(chan struct{}, 1)
+	go func() {
+		wg.Wait()
+		groupdone <- struct{}{}
+	}()
+	select {
+	case <-ctx.Done():
+		leftreader.Close()
+		right.Close()
+	case <-groupdone:
+		return
+	}
+	<-groupdone
+	return
+}
+
 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 +133,25 @@ 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)
@@ -94,14 +179,15 @@ func print_proxies(country string, proxy_type string, limit uint, timeout time.D
 	return 0
 }
 
-func get_endpoint(tunnels *ZGetTunnelsResponse, typ string, trial bool, force_port_field string) (string, error) {
-	var hostname string
-	for k := range tunnels.IPList {
+func get_endpoint(tunnels *ZGetTunnelsResponse, typ string, trial bool, force_port_field string) (*Endpoint, error) {
+	var hostname, ip string
+	for k, v := range tunnels.IPList {
 		hostname = k
+		ip = v
 		break
 	}
-	if hostname == "" {
-		return "", errors.New("No tunnels found in API response")
+	if hostname == "" || ip == "" {
+		return nil, errors.New("No tunnels found in API response")
 	}
 
 	var port uint16
@@ -128,10 +214,14 @@ func get_endpoint(tunnels *ZGetTunnelsResponse, typ string, trial bool, force_po
 				port = tunnels.Port.Peer
 			}
 		} else {
-			return "", errors.New("Unsupported port type")
+			return nil, errors.New("Unsupported port type")
 		}
 	}
-	return net.JoinHostPort(hostname, strconv.FormatUint(uint64(port), 10)), nil
+	return &Endpoint{
+		Host:    ip,
+		Port:    port,
+		TLSName: hostname,
+	}, nil
 }
 
 // Hop-by-hop headers. These are removed when sent to the backend.
@@ -179,76 +269,26 @@ func hijack(hijackable interface{}) (net.Conn, *bufio.ReadWriter, error) {
 	return conn, rw, nil
 }
 
-func rewriteConnectReq(req *http.Request, resolver *Resolver) error {
-	origHost := req.Host
-	origAddr, origPort, err := net.SplitHostPort(origHost)
-	if err == nil {
-		origHost = origAddr
+func flush(flusher interface{}) bool {
+	f, ok := flusher.(http.Flusher)
+	if !ok {
+		return false
 	}
-	addrs := resolver.Resolve(origHost)
-	if len(addrs) == 0 {
-		return errors.New("Can't resolve host")
-	}
-	if origPort == "" {
-		req.URL.Host = addrs[0]
-		req.Host = addrs[0]
-		req.RequestURI = addrs[0]
-	} else {
-		req.URL.Host = net.JoinHostPort(addrs[0], origPort)
-		req.Host = net.JoinHostPort(addrs[0], origPort)
-		req.RequestURI = net.JoinHostPort(addrs[0], origPort)
-	}
-	return nil
+	f.Flush()
+	return true
 }
 
-func rewriteReq(req *http.Request, resolver *Resolver) error {
-	origHost := req.URL.Host
-	origAddr, origPort, err := net.SplitHostPort(origHost)
-	if err == nil {
-		origHost = origAddr
-	}
-	addrs := resolver.Resolve(origHost)
-	if len(addrs) == 0 {
-		return errors.New("Can't resolve host")
-	}
-	if origPort == "" {
-		req.URL.Host = addrs[0]
-		req.Host = addrs[0]
-	} else {
-		req.URL.Host = net.JoinHostPort(addrs[0], origPort)
-		req.Host = net.JoinHostPort(addrs[0], origPort)
-	}
-	req.Header.Set("Host", origHost)
-	return nil
-}
-
-func makeConnReq(uri string, resolver *Resolver) (*http.Request, error) {
-	parsed_url, err := url.Parse(uri)
-	if err != nil {
-		return nil, err
-	}
-	origAddr, origPort, err := net.SplitHostPort(parsed_url.Host)
-	if err != nil {
-		origAddr = parsed_url.Host
-		switch strings.ToLower(parsed_url.Scheme) {
-		case "https":
-			origPort = "443"
-		case "http":
-			origPort = "80"
-		default:
-			return nil, errors.New("Unknown scheme")
+func copyBody(wr io.Writer, body io.Reader) {
+	buf := make([]byte, COPY_BUF)
+	for {
+		bread, read_err := body.Read(buf)
+		var write_err error
+		if bread > 0 {
+			_, write_err = wr.Write(buf[:bread])
+			flush(wr)
+		}
+		if read_err != nil || write_err != nil {
+			break
 		}
 	}
-	addrs := resolver.Resolve(origAddr)
-	if len(addrs) == 0 {
-		return nil, errors.New("Can't resolve host")
-	}
-	new_uri := net.JoinHostPort(addrs[0], origPort)
-	req, err := http.NewRequest("CONNECT", "http://"+new_uri, nil)
-	if err != nil {
-		return nil, err
-	}
-	req.RequestURI = new_uri
-	req.Host = new_uri
-	return req, nil
 }