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feat: create local proxy library that is Go Mobile-friendly (#64)
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fortuna authored Sep 7, 2023
1 parent 4eeee61 commit a5564f7
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Showing 8 changed files with 421 additions and 32 deletions.
8 changes: 5 additions & 3 deletions README.md
Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,8 @@ To integrate the SDK into a mobile app, follow these steps:

> **Note**: You must use `gomobile bind` on a package you create, not directly on the SDK packages.
An easy way to integrate with the SDK in a mobile app is by using the [`x/mobileproxy` library](./x/mobileproxy/)
to run a local web proxy that you can use to configure your app's networking libraries.

### Side Service

Expand Down Expand Up @@ -119,15 +121,15 @@ Beta features:
- Transport client strategies
- Proxyless strategies
- [ ] Encrypted DNS
- [x] Packet splitting
- [x] Packet splitting ([reference](https://pkg.go.dev/github.com/Jigsaw-Code/outline-sdk/transport/split))
- Proxy-based strategies
- [ ] HTTP Connect
- [x] SOCKS5 StreamDialer
- [x] SOCKS5 StreamDialer ([reference](https://pkg.go.dev/github.com/Jigsaw-Code/outline-sdk/transport/socks5))
- [ ] SOCKS5 PacketDialer

- Integration resources
- For Mobile apps
- [ ] Library to run a local SOCKS5 or HTTP-Connect proxy
- [x] Library to run a local SOCKS5 or HTTP-Connect proxy ([source](./x/mobileproxy/mobileproxy.go), [example Go usage](./x/examples/fetch-proxy/main.go), [example mobile usage](./x/examples/mobileproxy)).
- [x] Documentation on how to integrate the SDK into mobile apps
- [ ] Connectivity Test mobile app using [Capacitor](https://capacitorjs.com/)
- For Go apps
Expand Down
56 changes: 56 additions & 0 deletions x/examples/fetch-proxy/main.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,56 @@
// Copyright 2023 Jigsaw Operations LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package main

import (
"flag"
"io"
"log"
"net/http"
"net/url"
"os"

"github.com/Jigsaw-Code/outline-sdk/x/mobileproxy"
)

func main() {
transportFlag := flag.String("transport", "", "Transport config")
flag.Parse()

urlToFetch := flag.Arg(0)
if urlToFetch == "" {
log.Fatal("Need to pass the URL to fetch in the command-line")
}

proxy, err := mobileproxy.RunProxy("localhost:0", *transportFlag)
if err != nil {
log.Fatalf("Cmobileproxy start proxy: %v", err)
}

httpClient := &http.Client{Transport: &http.Transport{Proxy: http.ProxyURL(&url.URL{Scheme: "http", Host: proxy.Address()})}}

resp, err := httpClient.Get(urlToFetch)
if err != nil {
log.Fatalf("URL GET failed: %v", err)
}
defer resp.Body.Close()

_, err = io.Copy(os.Stdout, resp.Body)
if err != nil {
log.Fatalf("Read of page body failed: %v", err)
}

proxy.Stop(5)
}
12 changes: 7 additions & 5 deletions x/go.mod
Original file line number Diff line number Diff line change
Expand Up @@ -6,17 +6,19 @@ require (
github.com/Jigsaw-Code/outline-sdk v0.0.6
github.com/miekg/dns v1.1.54
github.com/stretchr/testify v1.8.2
golang.org/x/sys v0.8.0
golang.org/x/mobile v0.0.0-20230905140555-fbe1c053b6a9
golang.org/x/sys v0.11.0
)

require (
github.com/davecgh/go-spew v1.1.1 // indirect
github.com/kr/text v0.2.0 // indirect
github.com/pmezard/go-difflib v1.0.0 // indirect
github.com/shadowsocks/go-shadowsocks2 v0.1.5 // indirect
golang.org/x/crypto v0.9.0 // indirect
golang.org/x/mod v0.10.0 // indirect
golang.org/x/net v0.10.0 // indirect
golang.org/x/tools v0.9.1 // indirect
golang.org/x/crypto v0.12.0 // indirect
golang.org/x/mod v0.12.0 // indirect
golang.org/x/net v0.14.0 // indirect
golang.org/x/sync v0.3.0 // indirect
golang.org/x/tools v0.12.1-0.20230818130535-1517d1a3ba60 // indirect
gopkg.in/yaml.v3 v3.0.1 // indirect
)
25 changes: 14 additions & 11 deletions x/go.sum
Original file line number Diff line number Diff line change
Expand Up @@ -24,22 +24,25 @@ github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ
github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/crypto v0.0.0-20210220033148-5ea612d1eb83/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
golang.org/x/crypto v0.9.0 h1:LF6fAI+IutBocDJ2OT0Q1g8plpYljMZ4+lty+dsqw3g=
golang.org/x/crypto v0.9.0/go.mod h1:yrmDGqONDYtNj3tH8X9dzUun2m2lzPa9ngI6/RUPGR0=
golang.org/x/mod v0.10.0 h1:lFO9qtOdlre5W1jxS3r/4szv2/6iXxScdzjoBMXNhYk=
golang.org/x/mod v0.10.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
golang.org/x/crypto v0.12.0 h1:tFM/ta59kqch6LlvYnPa0yx5a83cL2nHflFhYKvv9Yk=
golang.org/x/crypto v0.12.0/go.mod h1:NF0Gs7EO5K4qLn+Ylc+fih8BSTeIjAP05siRnAh98yw=
golang.org/x/mobile v0.0.0-20230905140555-fbe1c053b6a9 h1:LaLfQUz4L1tfuOlrtEouZLZ0qHDwKn87E1NKoiudP/o=
golang.org/x/mobile v0.0.0-20230905140555-fbe1c053b6a9/go.mod h1:2jxcxt/JNJik+N+QcB8q308+SyrE3bu43+sGZDmJ02M=
golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
golang.org/x/net v0.10.0 h1:X2//UzNDwYmtCLn7To6G58Wr6f5ahEAQgKNzv9Y951M=
golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
golang.org/x/sync v0.2.0 h1:PUR+T4wwASmuSTYdKjYHI5TD22Wy5ogLU5qZCOLxBrI=
golang.org/x/net v0.14.0 h1:BONx9s002vGdD9umnlX1Po8vOZmrgH34qlHcD1MfK14=
golang.org/x/net v0.14.0/go.mod h1:PpSgVXXLK0OxS0F31C1/tv6XNguvCrnXIDrFMspZIUI=
golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.8.0 h1:EBmGv8NaZBZTWvrbjNoL6HVt+IVy3QDQpJs7VRIw3tU=
golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.11.0 h1:eG7RXZHdqOJ1i+0lgLgCpSXAp6M3LYlAo6osgSi0xOM=
golang.org/x/sys v0.11.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/tools v0.9.1 h1:8WMNJAz3zrtPmnYC7ISf5dEn3MT0gY7jBJfw27yrrLo=
golang.org/x/tools v0.9.1/go.mod h1:owI94Op576fPu3cIGQeHs3joujW/2Oc6MtlxbF5dfNc=
golang.org/x/tools v0.12.1-0.20230818130535-1517d1a3ba60 h1:o4bs4seAAlSiZQAZbO6/RP5XBCZCooQS3Pgc0AUjWts=
golang.org/x/tools v0.12.1-0.20230818130535-1517d1a3ba60/go.mod h1:Sc0INKfu04TlqNoRA1hgpFZbhYXHPr4V5DzpSBTPqQM=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
Expand Down
62 changes: 49 additions & 13 deletions x/httpproxy/connect_handler.go
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,6 @@
package httpproxy

import (
"fmt"
"io"
"net"
"net/http"
Expand All @@ -25,47 +24,84 @@ import (

type handler struct {
dialer transport.StreamDialer
client http.Client
}

var _ http.Handler = (*handler)(nil)

// ServeHTTP implements [http.Handler].ServeHTTP for CONNECT requests, using the internal [transport.StreamDialer].
func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
func (h *handler) ServeHTTP(proxyResp http.ResponseWriter, proxyReq *http.Request) {
// TODO(fortuna): For public services (not local), we need authentication and drain on failures to avoid fingerprinting.
if r.Method != http.MethodConnect {
http.Error(w, fmt.Sprintf("Method %v is not supported", r.Method), http.StatusMethodNotAllowed)
if proxyReq.Method == http.MethodConnect {
h.handleConnect(proxyResp, proxyReq)
return
} else if proxyReq.URL.Host != "" {
h.handleHTTPProxyRequest(proxyResp, proxyReq)
} else {
http.Error(proxyResp, "Not Found", http.StatusNotFound)
}
}

func (h *handler) handleHTTPProxyRequest(proxyResp http.ResponseWriter, proxyReq *http.Request) {
// We create a new request that uses a relative path + Host header, instead of the absolute URL in the proxy request.
targetReq, err := http.NewRequestWithContext(proxyReq.Context(), proxyReq.Method, proxyReq.URL.String(), proxyReq.Body)
if err != nil {
http.Error(proxyResp, "Error creating target request", http.StatusInternalServerError)
return
}
for key, values := range proxyReq.Header {
for _, value := range values {
targetReq.Header.Add(key, value)
}
}
targetResp, err := h.client.Do(targetReq)
if err != nil {
http.Error(proxyResp, "Failed to fetch destination", http.StatusServiceUnavailable)
return
}
defer targetResp.Body.Close()
for key, values := range targetResp.Header {
for _, value := range values {
proxyResp.Header().Add(key, value)
}
}
_, err = io.Copy(proxyResp, targetResp.Body)
if err != nil {
http.Error(proxyResp, "Failed write response", http.StatusServiceUnavailable)
return
}
}

func (h *handler) handleConnect(proxyResp http.ResponseWriter, proxyReq *http.Request) {
// Validate the target address.
_, portStr, err := net.SplitHostPort(r.Host)
_, portStr, err := net.SplitHostPort(proxyReq.Host)
if err != nil {
http.Error(w, "Authority is not a valid host:port", http.StatusBadRequest)
http.Error(proxyResp, "Authority is not a valid host:port", http.StatusBadRequest)
return
}
if portStr == "" {
// As per https://httpwg.org/specs/rfc9110.html#CONNECT.
http.Error(w, "Port number must be specified", http.StatusBadRequest)
http.Error(proxyResp, "Port number must be specified", http.StatusBadRequest)
return
}

// Dial the target.
targetConn, err := h.dialer.Dial(r.Context(), r.Host)
targetConn, err := h.dialer.Dial(proxyReq.Context(), proxyReq.Host)
if err != nil {
http.Error(w, "Failed to connect to target", http.StatusServiceUnavailable)
http.Error(proxyResp, "Failed to connect to target", http.StatusServiceUnavailable)
return
}
defer targetConn.Close()

hijacker, ok := w.(http.Hijacker)
hijacker, ok := proxyResp.(http.Hijacker)
if !ok {
http.Error(w, "Webserver doesn't support hijacking", http.StatusInternalServerError)
http.Error(proxyResp, "Webserver doesn't support hijacking", http.StatusInternalServerError)
return
}

httpConn, _, err := hijacker.Hijack()
if err != nil {
http.Error(w, "Failed to hijack connection", http.StatusInternalServerError)
http.Error(proxyResp, "Failed to hijack connection", http.StatusInternalServerError)
return
}
defer httpConn.Close()
Expand All @@ -88,5 +124,5 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// The resulting handler is currently vulnerable to probing attacks. It's ok as a localhost proxy
// but it may be vulnerable if used as a public proxy.
func NewConnectHandler(dialer transport.StreamDialer) http.Handler {
return &handler{dialer}
return &handler{dialer, *http.DefaultClient}
}
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