From 6aefe40b6dc86e76d77d86f5911a55e50c033254 Mon Sep 17 00:00:00 2001
From: Tom Wilkie <tom@weave.works>
Date: Wed, 12 Aug 2015 10:21:46 +0000
Subject: [PATCH] Add socks proxy.

---
 .gitignore       |  2 ++
 socks/Dockerfile |  7 ++++
 socks/Makefile   | 29 ++++++++++++++++
 socks/connect.sh | 23 +++++++++++++
 socks/main.go    | 87 ++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 148 insertions(+)
 create mode 100644 socks/Dockerfile
 create mode 100644 socks/Makefile
 create mode 100755 socks/connect.sh
 create mode 100644 socks/main.go

diff --git a/.gitignore b/.gitignore
index 5cd748c0c..78fe8261e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
 cover/cover
+socks/proxy
+socks/image.tar
diff --git a/socks/Dockerfile b/socks/Dockerfile
new file mode 100644
index 000000000..867cd6bc5
--- /dev/null
+++ b/socks/Dockerfile
@@ -0,0 +1,7 @@
+FROM gliderlabs/alpine
+MAINTAINER Weaveworks Inc <help@weave.works>
+WORKDIR /
+COPY proxy /
+EXPOSE 8000
+EXPOSE 8080
+ENTRYPOINT ["/proxy"]
diff --git a/socks/Makefile b/socks/Makefile
new file mode 100644
index 000000000..2daeda643
--- /dev/null
+++ b/socks/Makefile
@@ -0,0 +1,29 @@
+.PHONY: all clean
+
+IMAGE_TAR=image.tar
+IMAGE_NAME=weaveworks/socksproxy
+PROXY_EXE=proxy
+NETGO_CHECK=@strings $@ | grep cgo_stub\\\.go >/dev/null || { \
+	rm $@; \
+	echo "\nYour go standard library was built without the 'netgo' build tag."; \
+	echo "To fix that, run"; \
+	echo "    sudo go clean -i net"; \
+	echo "    sudo go install -tags netgo std"; \
+	false; \
+}
+
+all: $(IMAGE_TAR)
+
+$(IMAGE_TAR): Dockerfile $(PROXY_EXE)
+	docker build -t $(IMAGE_NAME) .
+	docker save $(IMAGE_NAME):latest > $@
+
+$(PROXY_EXE): *.go
+	go get -tags netgo ./$(@D)
+	go build -ldflags "-extldflags \"-static\" -linkmode=external" -tags netgo -o $@ ./$(@D)
+	$(NETGO_CHECK)
+
+clean:
+	-docker rmi $(IMAGE_NAME)
+	rm -rf $(PROXY_EXE) $(IMAGE_TAR)
+	go clean ./...
diff --git a/socks/connect.sh b/socks/connect.sh
new file mode 100755
index 000000000..0d5ef84da
--- /dev/null
+++ b/socks/connect.sh
@@ -0,0 +1,23 @@
+#!/bin/bash
+
+set -eu
+
+if [ $# -ne 1 ]; then
+	echo "Usage: $0 <host>"
+	exit 1
+fi
+
+HOST=$1
+
+echo "Starting proxy container..."
+PROXY_CONTAINER=$(ssh $HOST weave run -d weaveworks/socksproxy)
+
+function finish {
+	echo "Removing proxy container.."
+	ssh $HOST docker rm -f $PROXY_CONTAINER
+}
+trap finish EXIT
+
+PROXY_IP=$(ssh $HOST -- "docker inspect --format='{{.NetworkSettings.IPAddress}}' $PROXY_CONTAINER")
+echo 'Please configure your browser for proxy http://localhost:8080/proxy.pac'
+ssh -L8000:$PROXY_IP:8000 -L8080:$PROXY_IP:8080 $HOST docker attach $PROXY_CONTAINER
diff --git a/socks/main.go b/socks/main.go
new file mode 100644
index 000000000..c86ded74b
--- /dev/null
+++ b/socks/main.go
@@ -0,0 +1,87 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"strings"
+	"os"
+	"text/template"
+
+	socks5 "github.com/armon/go-socks5"
+	"github.com/weaveworks/weave/common"
+	"github.com/docker/docker/pkg/mflag"
+)
+
+const (
+	pacfile = `
+function FindProxyForURL(url, host) {
+	if(shExpMatch(host, "*.weave.local")) {
+		return "SOCKS5 localhost:8000";
+	}
+	{{range $key, $value := .}}
+	if (host == "{{$key}}") {
+		return "SOCKS5 localhost:8000";
+	}
+	{{end}}
+	return "DIRECT";
+}
+`
+)
+
+func main() {
+	var as []string
+	common.ListVar(&as, []string{"a", "-alias"}, []string{}, "Specify hostname aliases in the form alias:hostname.  Can be repeated.")
+	mflag.Parse()
+
+	var aliases = map[string]string{}
+	for _, a := range as {
+		parts := strings.SplitN(a, ":", 2)
+		if len(parts) != 2 {
+			fmt.Printf("'%s' is not a valid alias.\n", a)
+			mflag.Usage()
+			os.Exit(1)
+		}
+		aliases[parts[0]] = parts[1]
+	}
+
+	go socksProxy(aliases)
+
+	t := template.Must(template.New("pacfile").Parse(pacfile))
+	http.HandleFunc("/proxy.pac", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/x-ns-proxy-autoconfig")
+		t.Execute(w, aliases)
+	})
+
+	if err := http.ListenAndServe(":8080", nil); err != nil {
+		panic(err)
+	}
+}
+
+type aliasingResolver struct {
+	aliases map[string]string
+	socks5.NameResolver
+}
+
+func (r aliasingResolver) Resolve(name string) (net.IP, error) {
+	if alias, ok := r.aliases[name]; ok {
+		return r.NameResolver.Resolve(alias)
+	}
+	return r.NameResolver.Resolve(name)
+}
+
+func socksProxy(aliases map[string]string) {
+	conf := &socks5.Config{
+		Resolver: aliasingResolver{
+			aliases: aliases,
+			NameResolver: socks5.DNSResolver{},
+		},
+	}
+	server, err := socks5.New(conf)
+	if err != nil {
+		panic(err)
+	}
+	if err := server.ListenAndServe("tcp", ":8000"); err != nil {
+		panic(err)
+	}
+}