fix docker example

add docker support

.dockerignore

@@ -0,0 +1 @@
+bin/

Dockerfile

@@ -0,0 +1,14 @@
+FROM golang AS build
+
+WORKDIR /go/src/github.com/Snawoot/hola-proxy
+COPY . .
+RUN CGO_ENABLED=0 go build -a -tags netgo -ldflags '-s -w -extldflags "-static"'
+ADD https://curl.haxx.se/ca/cacert.pem /certs.crt
+RUN chmod 0644 /certs.crt
+
+FROM scratch
+COPY --from=build /go/src/github.com/Snawoot/hola-proxy/hola-proxy /
+COPY --from=build /certs.crt /etc/ssl/certs/ca-certificates.crt
+USER 9999:9999
+EXPOSE 8080/tcp
+ENTRYPOINT ["/hola-proxy", "-bind-address", "0.0.0.0:8080"]

README.md

@@ -14,10 +14,21 @@ Application is capable to forward traffic via proxies in datacenters (flag `-pro
 
 Pre-built binaries available on [releases](https://github.com/Snawoot/hola-proxy/releases/latest) page.
 
-Alternatively, you may install hola-proxy from source:
+Alternatively, you may install hola-proxy from source. Run within source directory
 
 ```
-go get github.com/Snawoot/hola-proxy
+go install
+```
+
+Docker image is available as well. Here is an example for running proxy via DE as a background service:
+
+```sh
+docker run -d \
+    --security-opt no-new-privileges \
+    -p 127.0.0.1:8080:8080 \
+    --restart unless-stopped \
+    --name hola-proxy \
+    yarmak/hola-proxy -country de
 ```
 
 ## Usage
@@ -111,10 +122,13 @@ Usage of /home/user/go/bin/hola-proxy:
     	output proxy list and exit
   -proxy-type string
     	proxy type: direct or peer (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)
+
 ```

go.mod

@@ -2,4 +2,8 @@ module github.com/Snawoot/hola-proxy
 
 go 1.13
 
-require github.com/google/uuid v1.1.1
+require (
+	github.com/AdguardTeam/dnsproxy v0.25.0
+	github.com/google/uuid v1.1.1
+	github.com/miekg/dns v1.1.29
+)

go.sum

@@ -1,2 +1,62 @@
+github.com/AdguardTeam/dnsproxy v0.25.0 h1:BTUPrrwB01GeQW5d2Xx4pH5HOFXcZxN1MTeNXXuy6vQ=
+github.com/AdguardTeam/dnsproxy v0.25.0/go.mod h1:z2EljVLJQXFGZcP9pWABftXm9UxpLNqls7H6bMcIvEY=
+github.com/AdguardTeam/golibs v0.4.0 h1:4VX6LoOqFe9p9Gf55BeD8BvJD6M6RDYmgEiHrENE9KU=
+github.com/AdguardTeam/golibs v0.4.0/go.mod h1:skKsDKIBB7kkFflLJBpfGX+G8QFTx0WKUzB6TIgtUj4=
+github.com/aead/chacha20 v0.0.0-20180709150244-8b13a72661da h1:KjTM2ks9d14ZYCvmHS9iAKVt9AyzRSqNU1qabPih5BY=
+github.com/aead/chacha20 v0.0.0-20180709150244-8b13a72661da/go.mod h1:eHEWzANqSiWQsof+nXEI9bUVUyV6F53Fp89EuCh2EAA=
+github.com/aead/poly1305 v0.0.0-20180717145839-3fee0db0b635 h1:52m0LGchQBBVqJRyYYufQuIbVqRawmubW3OFGqK1ekw=
+github.com/aead/poly1305 v0.0.0-20180717145839-3fee0db0b635/go.mod h1:lmLxL+FV291OopO93Bwf9fQLQeLyt33VJRUg5VJ30us=
+github.com/ameshkov/dnscrypt v1.1.0 h1:2vAt5dD6ZmqlAxEAfzRcLBnkvdf8NI46Kn9InSwQbSI=
+github.com/ameshkov/dnscrypt v1.1.0/go.mod h1:ikduAxNLCTEfd1AaCgpIA5TgroIVQ8JY3Vb095fiFJg=
+github.com/ameshkov/dnsstamps v1.0.1 h1:LhGvgWDzhNJh+kBQd/AfUlq1vfVe109huiXw4JhnPug=
+github.com/ameshkov/dnsstamps v1.0.1/go.mod h1:Ii3eUu73dx4Vw5O4wjzmT5+lkCwovjzaEZZ4gKyIH5A=
+github.com/beefsack/go-rate v0.0.0-20180408011153-efa7637bb9b6/go.mod h1:6YNgTHLutezwnBvyneBbwvB8C82y3dcoOj5EQJIdGXA=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-test/deep v1.0.5/go.mod h1:QV8Hv/iy04NyLBxAdO9njL0iVPN1S4d/A3NVv1V36o8=
 github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
+github.com/joomcode/errorx v1.0.1 h1:CalpDWz14ZHd68fIqluJasJosAewpz2TFaJALrUxjrk=
+github.com/joomcode/errorx v1.0.1/go.mod h1:kgco15ekB6cs+4Xjzo7SPeXzx38PbJzBwbnu9qfVNHQ=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/miekg/dns v1.1.29 h1:xHBEhR+t5RzcFJjBLJlax2daXOrTYtr9z4WdKEfWFzg=
+github.com/miekg/dns v1.1.29/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
+github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
+github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sparrc/go-ping v0.0.0-20190613174326-4e5b6552494c/go.mod h1:eMyUVp6f/5jnzM+3zahzl7q6UXLbgSc3MKg/+ow9QW0=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20200323165209-0ec3e9974c59/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/crypto v0.0.0-20200403201458-baeed622b8d8 h1:fpnn/HnJONpIu6hkXi1u/7rR0NzilgWr4T0JmWkEitk=
+golang.org/x/crypto v0.0.0-20200403201458-baeed622b8d8/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20190923162816-aa69164e4478/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e h1:3G+cUijn7XD+S4eJFddp53Pv7+slrESplyjG25HgL+k=
+golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20200317015054-43a5402ce75a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200331124033-c3d80250170d h1:nc5K6ox/4lTFbMVSL9WRR81ixkcwXThoiF6yf+R9scA=
+golang.org/x/sys v0.0.0-20200331124033-c3d80250170d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
+golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191216052735-49a3e744a425/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

handler.go

@@ -6,9 +6,8 @@ import (
     "net/http/httputil"
     "crypto/tls"
     "strings"
-    "context"
-    "time"
     "net/url"
+    "bufio"
 )
 
 type AuthProvider func() string
@@ -18,9 +17,10 @@ type ProxyHandler struct {
     upstream string
     logger *CondLogger
     httptransport http.RoundTripper
+    resolver *Resolver
 }
 
-func NewProxyHandler(upstream string, auth AuthProvider, logger *CondLogger) *ProxyHandler {
+func NewProxyHandler(upstream string, auth AuthProvider, resolver *Resolver, logger *CondLogger) *ProxyHandler {
     proxyurl, err := url.Parse("https://" + upstream)
     if err != nil {
         panic(err)
@@ -33,56 +33,183 @@ func NewProxyHandler(upstream string, auth AuthProvider, logger *CondLogger) *Pr
         upstream: upstream,
         logger: logger,
         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)
-    req.Header.Set("Proxy-Authorization", s.auth())
     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.StatusInternalServerError)
+            http.Error(wr, "Can't dial tls upstream", http.StatusBadGateway)
             return
-        defer conn.Close()
         }
-        hj, ok := wr.(http.Hijacker)
-		if !ok {
-            s.logger.Critical("Webserver doesn't support hijacking")
-			http.Error(wr, "Webserver doesn't support hijacking", http.StatusInternalServerError)
-			return
-		}
-        localconn, _, err := hj.Hijack()
+
+        _, 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
+
+        // Upgrade client connection
+        localconn, _, err := hijack(wr)
         if err != nil {
             s.logger.Error("Can't hijack client connection: %v", err)
             http.Error(wr, "Can't hijack client connection", http.StatusInternalServerError)
             return
         }
-        var emptytime time.Time
-        err = localconn.SetDeadline(emptytime)
-        if err != nil {
-            s.logger.Error("Can't clear deadlines on local connection: %v", err)
-            http.Error(wr, "Can't clear deadlines on local connection", http.StatusInternalServerError)
-            return
+        defer localconn.Close()
+
+        if len(responseBytes) > 0 {
+            _, err = localconn.Write(responseBytes)
+            if err != nil {
+                return
+            }
         }
-        conn.Write(rawreq)
-        proxy(context.TODO(), localconn, conn)
+        proxy(req.Context(), localconn, conn)
     } else {
-        req.RequestURI = ""
         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)

main.go

@@ -42,6 +42,7 @@ type CLIArgs struct {
     verbosity int
     timeout, rotate time.Duration
     proxy_type string
+    resolver string
 }
 
 
@@ -57,6 +58,9 @@ func parse_args() CLIArgs {
     flag.DurationVar(&args.timeout, "timeout", 10 * time.Second, "timeout for network operations")
     flag.DurationVar(&args.rotate, "rotate", 1 * time.Hour, "rotate user ID once per given period")
     flag.StringVar(&args.proxy_type, "proxy-type", "direct", "proxy type: direct or peer")
+    flag.StringVar(&args.resolver, "resolver", "https://cloudflare-dns.com/dns-query",
+                   "DNS/DoH/DoT resolver to workaround Hola blocked hosts. " +
+                   "See https://github.com/ameshkov/dnslookup/ for upstream DNS URL format.")
     flag.Parse()
     if args.country == "" {
         arg_fail("Country can't be empty string.")
@@ -67,13 +71,13 @@ func parse_args() CLIArgs {
     return args
 }
 
-func main() {
+func run() int {
     args := parse_args()
     if args.list_countries {
-        os.Exit(print_countries(args.timeout))
+        return print_countries(args.timeout)
     }
     if args.list_proxies {
-        os.Exit(print_proxies(args.country, args.limit, args.timeout))
+        return print_proxies(args.country, args.limit, args.timeout)
     }
 
     logWriter := NewLogWriter(os.Stderr)
@@ -88,19 +92,33 @@ func main() {
     proxyLogger := NewCondLogger(log.New(logWriter, "PROXY   : ",
                                 log.LstdFlags | log.Lshortfile),
                                 args.verbosity)
+    mainLogger.Info("Constructing fallback DNS upstream...")
+    resolver, err := NewResolver(args.resolver, args.timeout)
+    if err != nil {
+        mainLogger.Critical("Unable to instantiate DNS resolver: %v", err)
+        return 6
+    }
     mainLogger.Info("Initializing configuration provider...")
     auth, tunnels, err := CredService(args.rotate, args.timeout, args.country, credLogger)
     if err != nil {
-        os.Exit(4)
+        mainLogger.Critical("Unable to instantiate credential service: %v", err)
+        logWriter.Close()
+        return 4
     }
     endpoint, err := get_endpoint(tunnels, args.proxy_type)
     if err != nil {
         mainLogger.Critical("Unable to determine proxy endpoint: %v", err)
-        os.Exit(5)
+        logWriter.Close()
+        return 5
     }
     mainLogger.Info("Starting proxy server...")
-    handler := NewProxyHandler(endpoint, auth, proxyLogger)
+    handler := NewProxyHandler(endpoint, auth, resolver, proxyLogger)
     err = http.ListenAndServe(args.bind_address, handler)
     mainLogger.Critical("Server terminated with a reason: %v", err)
     mainLogger.Info("Shutting down...")
+    return 0
+}
+
+func main() {
+    os.Exit(run())
 }

resolver.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"github.com/AdguardTeam/dnsproxy/upstream"
+	"github.com/miekg/dns"
+    "time"
+)
+
+type Resolver struct {
+    upstream upstream.Upstream
+}
+
+const DOT = 0x2e
+
+func NewResolver(address string, timeout time.Duration) (*Resolver, error) {
+    opts := upstream.Options{Timeout: timeout}
+	u, err := upstream.AddressToUpstream(address, opts)
+	if err != nil {
+        return nil, err
+    }
+    return &Resolver{upstream: u}, nil
+}
+
+func (r *Resolver) ResolveA(domain string) []string {
+    res := make([]string, 0)
+    if len(domain) == 0 {
+        return res
+    }
+    if domain[len(domain)-1] != DOT {
+        domain = domain + "."
+    }
+    req := dns.Msg{}
+    req.Id = dns.Id()
+    req.RecursionDesired = true
+    req.Question = []dns.Question{
+        {Name: domain, Qtype: dns.TypeA, Qclass: dns.ClassINET},
+    }
+    reply, err := r.upstream.Exchange(&req)
+    if err != nil {
+        return res
+    }
+    for _, rr := range reply.Answer {
+        if a, ok := rr.(*dns.A); ok {
+            res = append(res, a.A.String())
+        }
+    }
+    return res
+}
+
+func (r *Resolver) ResolveAAAA(domain string) []string {
+    res := make([]string, 0)
+    if len(domain) == 0 {
+        return res
+    }
+    if domain[len(domain)-1] != DOT {
+        domain = domain + "."
+    }
+    req := dns.Msg{}
+    req.Id = dns.Id()
+    req.RecursionDesired = true
+    req.Question = []dns.Question{
+        {Name: domain, Qtype: dns.TypeAAAA, Qclass: dns.ClassINET},
+    }
+    reply, err := r.upstream.Exchange(&req)
+    if err != nil {
+        return res
+    }
+    for _, rr := range reply.Answer {
+        if a, ok := rr.(*dns.AAAA); ok {
+            res = append(res, a.AAAA.String())
+        }
+    }
+    return res
+}
+
+func (r *Resolver) Resolve(domain string) []string {
+    res := r.ResolveA(domain)
+    if len(res) == 0 {
+        res = r.ResolveAAAA(domain)
+    }
+    return res
+}

utils.go

@@ -14,6 +14,8 @@ import (
     "strings"
     "strconv"
     "net/http"
+    "net/url"
+    "bufio"
 )
 
 func basic_auth_header(login, password string) string {
@@ -115,6 +117,7 @@ var hopHeaders = []string{
 	"Connection",
 	"Keep-Alive",
 	"Proxy-Authenticate",
+	"Proxy-Connection",
 	"Te", // canonicalized version of "TE"
 	"Trailers",
 	"Transfer-Encoding",
@@ -135,3 +138,94 @@ func delHopHeaders(header http.Header) {
 	}
 }
 
+func hijack(hijackable interface{}) (net.Conn, *bufio.ReadWriter, error) {
+    hj, ok := hijackable.(http.Hijacker)
+    if !ok {
+        return nil, nil, errors.New("Connection doesn't support hijacking")
+    }
+    conn, rw, err := hj.Hijack()
+    if err != nil {
+        return nil, nil, err
+    }
+    var emptytime time.Time
+    err = conn.SetDeadline(emptytime)
+    if err != nil {
+        conn.Close()
+        return nil, nil, err
+    }
+    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
+    }
+    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
+}
+
+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")
+        }
+    }
+    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
+}