initial commit

README.md

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+# Mole
+
+Mole creates publicly accessible HTTP/HTTPS/TCP/UDP tunnels for local development.
+Tunnels are implemented using ssh remote port forwarding. Subdomains are assigned
+using an auto-incrementing id for every forwarding request.
+
+## Installation
+
+Install the mole server. You will need go and openssh installed before preceeding.
+
+```bash
+go get -u github.com/michalnicp/mole
+```
+
+Generate the ssh host key file.
+
+```bash
+ssh-keygen -t rsa -b 2048 -f /etc/mole/ssh_host_key
+```
+
+Start mole.
+
+```bash
+$ mole
+mole version 0.0.0
+```
+
+## Configuration
+
+Mole is configured using environment variables
+
+| Variable              | Default           | Description                                 |
+|-----------------------|-------------------|---------------------------------------------|
+| `SERVER_NAME`         |                   | The fully qualified domain name (hostname). |
+| `HTTP_ADDR`           | `:8080`           | The http server address to listen on.       |
+| `SSH_ADDR`            | `:2022`           | The ssh server address to listen on.        |
+| `SSH_HOST_KEY_PATH`   | `ssh_host_key`    | The path to the ssh server host key file.   |
+| `SSH_AUTHORIZED_KEYS` | `authorized_keys` | The path to the authorized keys file.       |
+
+## Quickstart
+
+This quickstart assumes that the `mole` server is running and available at `example.com`.
+You can use any ssh client that supports remote forwarding. For example, using `openssh`
+
+```bash
+$ ssh example.com -p 2022 -R 8000:localhost:8000
+mole version 0.0.0
+forwarding http://1.example.com->localhost:8000
+```
+
+Test using `ncat`. The following will start `ncat` listening on port `8000`
+
+```bash
+$ printf 'HTTP/1.1 200 OK\r\n' | ncat -l 8000
+```
+
+Then, in another terminal, make an http request using `curl`
+
+```bash
+$ curl 1.example.com
+```
+
+You should see the following output from `ncat`
+
+```bash
+$ printf 'HTTP/1.1 200 OK\r\n' | ncat -l 8000
+GET / HTTP/1.1
+Host: 1.example.com
+User-Agent: curl/7.68.0
+Accept: */*
+
+```

go.mod

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+module github.com/michalnicp/mole
+
+go 1.13
+
+require (
+	github.com/caarlos0/env v3.5.0+incompatible
+	github.com/fsnotify/fsnotify v1.4.7
+	golang.org/x/crypto v0.0.0-20191128160524-b544559bb6d1
+	golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3
+	golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e // indirect
+)

go.sum

@@ -0,0 +1,14 @@
+github.com/caarlos0/env v3.5.0+incompatible h1:Yy0UN8o9Wtr/jGHZDpCBLpNrzcFLLM2yixi/rBrKyJs=
+github.com/caarlos0/env v3.5.0+incompatible/go.mod h1:tdCsowwCzMLdkqRYDlHpZCp2UooDD3MspDBjZ2AD02Y=
+github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
+github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191128160524-b544559bb6d1 h1:anGSYQpPhQwXlwsu5wmfq0nWkCNaMEMUwAv13Y92hd8=
+golang.org/x/crypto v0.0.0-20191128160524-b544559bb6d1/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 h1:0GoQqolDA55aaLxZyTzK/Y2ePZzZTUrRacwib7cNsYQ=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+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 v0.0.0-20191120155948-bd437916bb0e h1:N7DeIrjYszNmSW409R3frPPwglRwMkXSBzwVbkOjLLA=
+golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

main.go

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+package main
+
+import (
+	"log"
+	"net/http"
+	"net/http/httputil"
+	"os"
+	"os/signal"
+	"strconv"
+	"strings"
+	"syscall"
+
+	"github.com/caarlos0/env"
+	"github.com/michalnicp/mole/ssh"
+)
+
+type config struct {
+	// ServerName is the server's fully qualified domain name (hostname).
+	ServerName        string `env:"SERVER_NAME"`
+	HTTPAddr          string `env:"HTTP_ADDR" envDefault:":8080"`
+	SSHAddr           string `env:"SSH_ADDR" envDefault:":2022"`
+	SSHHostKey        string `env:"SSH_HOST_KEY" envDefault:"ssh_host_key"`
+	SSHAuthorizedKeys string `env:"SSH_AUTHORIZED_KEYS" envDefault:"authorized_keys"`
+}
+
+func main() {
+	log.SetFlags(log.LstdFlags | log.Lshortfile)
+
+	// read config from env
+	var cfg config
+	if err := env.Parse(&cfg); err != nil {
+		log.Fatalf("parse environment: %v", err)
+	}
+
+	// create ssh server
+	sshServer, err := ssh.NewServer(cfg.SSHAddr)
+	if err != nil {
+		log.Fatalf("create ssh server: %v", err)
+	}
+
+	if err := sshServer.Start(); err != nil {
+		log.Fatalf("start ssh server: %v", err)
+	}
+
+	// create reverse proxy
+	domain := cfg.ServerName
+	proxy := &httputil.ReverseProxy{
+		Director: func(req *http.Request) {
+			subdomain := strings.TrimSuffix(req.Host, "."+domain)
+			id64, err := strconv.ParseUint(subdomain, 10, 64)
+			if err != nil {
+				log.Printf("parse host: %s: %v", req.Host, err)
+				return
+			}
+			id := uint(id64)
+
+			addr, ok := sshServer.GetForwardAddr(id)
+			if !ok {
+				log.Printf("forward address not found: %d", id)
+				return
+			}
+
+			// If there was an error above this line, the scheme will not be set.
+			// This results in the request failing with a 502 Bad Gateway, which
+			// is what we want. See proxy.ErrorHandler.
+
+			req.URL.Scheme = "http"
+			req.URL.Host = addr
+
+			// TODO: Should we modify req.Host as well?
+			// req.Host = req.URL.Host
+		},
+		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
+			if err.Error() != "unsupported protocol scheme \"\"" {
+				log.Printf("http: proxy error: %v", err)
+			}
+			w.WriteHeader(http.StatusBadGateway)
+		},
+	}
+
+	httpServer := http.Server{
+		Addr:    cfg.HTTPAddr,
+		Handler: proxy,
+	}
+
+	go func() {
+		log.Printf("starting http server; http_addr=%s", cfg.HTTPAddr)
+		if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			log.Printf("start http server: %v", err)
+		}
+	}()
+
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+
+	s := <-sigs
+	log.Printf("caught %s, shutting down", s)
+
+	if err := httpServer.Close(); err != nil {
+		log.Printf("close http server: %v", err)
+	}
+
+	if err := sshServer.Close(); err != nil {
+		log.Printf("close ssh server: %v", err)
+	}
+
+	// FIXME: get this down to 2
+	// time.Sleep(300 * time.Millisecond)
+	// pprof.Lookup("goroutine").WriteTo(os.Stdout, 1)
+}