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|
package main
import (
"bytes"
"errors"
"flag"
"fmt"
"net"
"net/http"
"os"
"time"
"github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/container"
"github.com/docker/docker/api/types/network"
"github.com/docker/go-connections/nat"
)
const (
vpnContainerName = "registry.darknebu.la/circus/vpn"
)
var vpnContainerID string
var remoteAddress *string
var remotePort *int
func registerAccessFlags() {
remoteAddress = flag.String("vpnRemoteAddress", "", "The remote domain name or IP the VPN will run on")
remotePort = flag.Int("vpnRemotePort", 1194, "The port the VPN should listen on")
}
func startVPN() (err error) {
// First: try to stop an existing container with that name, to avoid collision
// This container may exist if we didn't properly clean up on the last run, e.g. if the companion crashed.
stopVPN()
// stopVPN() as first command in startVPN()... This looks strange, but is perfectly fine ;)
// Set up our context and Docker CLI connection
setupContext()
setupDockerCLI()
// Set up VPN host network
if vpnHostNetworkID == "" {
id, err := setupNetwork(getVPNNetworkName(), false)
if err != nil {
return err
}
vpnHostNetworkID = id
}
// Set up container network
if containerNetworkID == "" {
id, err := setupNetwork(getChallengeNetworkName(), true)
if err != nil {
return err
}
containerNetworkID = id
}
// Get subnet of challenge container network, to hand it over to our VPN container for routes
inspectResp, err := dockerCli.NetworkInspect(dockerCtx, containerNetworkID, types.NetworkInspectOptions{})
if err != nil {
return err
}
// Parse subnet (in CIDR notation)
_, ipnet, err := net.ParseCIDR(inspectResp.IPAM.Config[0].Subnet)
if err != nil {
return err
}
// Create VPN container
resp, err := dockerCli.ContainerCreate(dockerCtx, &container.Config{
Image: vpnContainerName,
Env: []string{
fmt.Sprintf("remoteAddress=%s", *remoteAddress),
fmt.Sprintf("remotePort=%d", *remotePort),
fmt.Sprintf("subnet=%s", ipnet.IP.String()),
fmt.Sprintf("subnetMask=%d.%d.%d.%d", ipnet.Mask[0], ipnet.Mask[1], ipnet.Mask[2], ipnet.Mask[3]),
},
ExposedPorts: map[nat.Port]struct{}{
"1194/udp": {},
},
}, &container.HostConfig{
Privileged: true,
PortBindings: nat.PortMap{
"1194/udp": []nat.PortBinding{
{
HostIP: "0.0.0.0",
HostPort: fmt.Sprintf("%d", *remotePort),
},
},
},
}, &network.NetworkingConfig{
EndpointsConfig: map[string]*network.EndpointSettings{
"startpoint": {
NetworkID: vpnHostNetworkID,
},
},
}, "")
if err != nil {
return err
}
// Attach container network to VPN container
err = dockerCli.NetworkConnect(dockerCtx, containerNetworkID, resp.ID, &network.EndpointSettings{})
if err != nil {
return err
}
// Start container
err = dockerCli.ContainerStart(dockerCtx, resp.ID, types.ContainerStartOptions{})
if err != nil {
return err
}
// We now need to do a little stunt. If the companion is started inside a container, it's not possible to dial to port 9999 of the VPN container.
// However, getCertificate() requires that port 9999 of the VPN container hosts the configuration files for our client.
// That means we need to attach our own container - thanks to --privileged mode - into the VPN container network.
// We get the ID of our container from the "hostname" environment variable. That's a bit dirty, but works for the moment. TODO: solve this better.
err = dockerCli.NetworkConnect(dockerCtx, vpnHostNetworkID, os.Getenv("HOSTNAME"), &network.EndpointSettings{})
if err != nil {
return err
}
vpnContainerID = resp.ID
return nil
}
func stopVPN() {
setupContext()
setupDockerCLI()
timeout := time.Second * 5
dockerCli.ContainerStop(dockerCtx, vpnContainerID, &timeout)
// We need to undo our stunt! Else, the network won't be deletable because "there are active endpoints"
dockerCli.NetworkDisconnect(dockerCtx, vpnHostNetworkID, os.Getenv("HOSTNAME"), true)
vpnContainerID = ""
}
func getCertificate() (string, error) {
if vpnContainerID == "" {
return "", errors.New("VPN container not up")
}
// Get IP of VPN container
inspectJSON, err := dockerCli.ContainerInspect(dockerCtx, vpnContainerID)
if err != nil {
return "", err
}
// get certificate
var certResponse *http.Response
// retry for 10 seconds to dial to the VPN container
for i := 0; i < 10; i++ {
// Check if the VPN container is already part of our challenge container network
if inspectJSON.NetworkSettings.Networks[getVPNNetworkName()] != nil {
// it is - get the IP address and dial to it
certResponse, err = http.Get(fmt.Sprintf("http://%s:9999/", inspectJSON.NetworkSettings.Networks[getVPNNetworkName()].IPAddress))
if err == nil {
break
}
}
time.Sleep(time.Second)
}
if err != nil || certResponse == nil {
return "", err
}
buffer := make([]byte, 1024)
certResponse.Body.Read(buffer)
return string(bytes.Trim(buffer, "\x00")), nil
}
|
