sshfwd/main.go

116 lines
2.3 KiB
Go

package main
import (
"context"
"log"
"net"
"net/http"
"os"
"os/signal"
"path/filepath"
"regexp"
"strconv"
"strings"
"github.com/gliderlabs/ssh"
)
const (
domainName = "prox.int"
portRange = "7000-7999"
bindHost = "[::1]"
)
var filterName = regexp.MustCompile("[^a-z0-9-]+")
func main() {
ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, os.Kill)
defer stop()
run(ctx)
}
func run(ctx context.Context) {
lis, err := net.Listen("tcp", envMust("SSH_LISTEN"))
if err != nil {
log.Fatal(err.Error())
}
var opts []ssh.Option
opts = append(
opts,
ssh.NoPty(),
)
hostKeys := envMust("SSH_HOSTKEYS")
files, err := os.ReadDir(hostKeys)
if err != nil {
log.Fatal(err)
}
for _, f := range files {
opts = append(opts, ssh.HostKeyFile(filepath.Join(hostKeys, f.Name())))
}
loadTemplates()
srv := &server{
bindHost: envDefault("SSH_HOST", bindHost),
domainName: envDefault("SSH_DOMAIN", domainName),
domainSuffix: envDefault("SSH_DOMAIN_SUFFIX", "."+domainName),
}
opts = append(opts, srv.optAuthUser()...)
http.HandleFunc("/", srv.handleHTTP)
mux := New(lis, srv.serveHTTP(ctx), srv.serveSSH(ctx, opts...))
listen := mux.Listener.Addr().String()
if idx := strings.LastIndex(listen, ":"); idx >= 0 {
if i, err := strconv.Atoi(listen[idx+1:]); err == nil {
srv.listenPort = uint32(i)
}
}
if r := envDefault("SSH_PORTRANGE", portRange); r != "" {
sp := strings.SplitN(r, "-", 2)
if len(sp) == 1 {
log.Fatal("SSH_PORTRANGE should have start and end like 7000-7999")
}
var p uint64
if p, err = strconv.ParseUint(sp[0], 10, 32); err != nil {
log.Fatal("SSH_PORTRANGE start port invalid:", sp[0])
}
srv.portStart = uint32(p)
if p, err = strconv.ParseUint(sp[1], 10, 32); err != nil {
log.Fatal("SSH_PORTRANGE end port invalid:", sp[1])
}
srv.portEnd = uint32(p)
if srv.portStart > srv.portEnd {
log.Fatalf("SSH_PORTRANGE is reversed %d > %d", srv.portStart, srv.portEnd)
}
}
if err = mux.Serve(ctx); err != nil {
log.Fatal()
}
}
func envMust(s string) string {
v := os.Getenv(s)
if v == "" {
log.Fatal("missing env ", s)
}
log.Println("env", s, "==", v)
return v
}
func envDefault(s, d string) string {
v := os.Getenv(s)
if v == "" {
v = d
}
log.Println("env", s, "==", v)
return v
}