Fix #90 add env variable OPENVPN_TARGET_IP

Dockerfile

@@ -34,6 +34,7 @@ ENV VPNSP=pia \
     PROTOCOL=udp \
     OPENVPN_VERBOSITY=1 \
     OPENVPN_ROOT=no \
+    OPENVPN_TARGET_IP= \
     TZ= \
     # PIA only
     PASSWORD= \

README.md

@@ -161,6 +161,7 @@ docker run --rm --network=container:pia alpine:3.11 wget -qO- https://ipinfo.io
 | `TZ` | | Specify a timezone to use i.e. `Europe/London` |
 | `OPENVPN_VERBOSITY` | `1` | Openvpn verbosity level from 0 to 6 |
 | `OPENVPN_ROOT` | `no` | Run OpenVPN as root, `yes` or `no` |
+| `OPENVPN_TARGET_IP` | | Specify a target VPN server IP address to use, valid for Mullvad and Private Internet Access |
 
 ## Connect to it
 

cmd/main.go

@@ -130,12 +130,12 @@ func main() {
 	var connections []models.OpenVPNConnection
 	switch allSettings.VPNSP {
 	case "pia":
-		connections, err = piaConf.GetOpenVPNConnections(allSettings.PIA.Region, allSettings.OpenVPN.NetworkProtocol, allSettings.PIA.Encryption)
+		connections, err = piaConf.GetOpenVPNConnections(allSettings.PIA.Region, allSettings.OpenVPN.NetworkProtocol, allSettings.PIA.Encryption, allSettings.OpenVPN.TargetIP)
 		e.FatalOnError(err)
 		err = piaConf.BuildConf(connections, allSettings.PIA.Encryption, allSettings.OpenVPN.Verbosity, uid, gid, allSettings.OpenVPN.Root)
 		e.FatalOnError(err)
 	case "mullvad":
-		connections, err = mullvadConf.GetOpenVPNConnections(allSettings.Mullvad.Country, allSettings.Mullvad.City, allSettings.Mullvad.ISP, allSettings.OpenVPN.NetworkProtocol, allSettings.Mullvad.Port)
+		connections, err = mullvadConf.GetOpenVPNConnections(allSettings.Mullvad.Country, allSettings.Mullvad.City, allSettings.Mullvad.ISP, allSettings.OpenVPN.NetworkProtocol, allSettings.Mullvad.Port, allSettings.OpenVPN.TargetIP)
 		e.FatalOnError(err)
 		err = mullvadConf.BuildConf(connections, allSettings.OpenVPN.Verbosity, uid, gid, allSettings.OpenVPN.Root)
 		e.FatalOnError(err)

docker-compose.yml

@@ -19,6 +19,7 @@ services:
       - PROTOCOL=udp
       - OPENVPN_VERBOSITY=1
       - OPENVPN_ROOT=no
+      - OPENVPN_TARGET_IP=
       - TZ=
 
       # PIA only

internal/mullvad/conf.go

@@ -2,13 +2,14 @@ package mullvad
 
 import (
 	"fmt"
+	"net"
 
 	"github.com/qdm12/golibs/files"
 	"github.com/qdm12/private-internet-access-docker/internal/constants"
 	"github.com/qdm12/private-internet-access-docker/internal/models"
 )
 
-func (c *configurator) GetOpenVPNConnections(country models.MullvadCountry, city models.MullvadCity, provider models.MullvadProvider, protocol models.NetworkProtocol, customPort uint16) (connections []models.OpenVPNConnection, err error) {
+func (c *configurator) GetOpenVPNConnections(country models.MullvadCountry, city models.MullvadCity, provider models.MullvadProvider, protocol models.NetworkProtocol, customPort uint16, targetIP net.IP) (connections []models.OpenVPNConnection, err error) {
 	servers := constants.MullvadServerFilter(country, city, provider)
 	if len(servers) == 0 {
 		return nil, fmt.Errorf("no server found for country %q, city %q and ISP %q", country, city, provider)
@@ -19,9 +20,18 @@ func (c *configurator) GetOpenVPNConnections(country models.MullvadCountry, city
 			port = customPort
 		}
 		for _, IP := range server.IPs {
-			connections = append(connections, models.OpenVPNConnection{IP: IP, Port: port, Protocol: protocol})
+			if targetIP != nil {
+				if targetIP.Equal(IP) {
+					return []models.OpenVPNConnection{{IP: IP, Port: port, Protocol: protocol}}, nil
+				}
+			} else {
+				connections = append(connections, models.OpenVPNConnection{IP: IP, Port: port, Protocol: protocol})
+			}
 		}
 	}
+	if targetIP != nil {
+		return nil, fmt.Errorf("target IP address %q not found in IP addresses", targetIP)
+	}
 	return connections, nil
 }
 

internal/mullvad/mullvad.go

@@ -1,6 +1,8 @@
 package mullvad
 
 import (
+	"net"
+
 	"github.com/qdm12/golibs/files"
 	"github.com/qdm12/golibs/logging"
 	"github.com/qdm12/golibs/network"
@@ -11,7 +13,7 @@ const logPrefix = "Mullvad configurator"
 
 // Configurator contains methods to download, read and modify the openvpn configuration to connect as a client
 type Configurator interface {
-	GetOpenVPNConnections(country models.MullvadCountry, city models.MullvadCity, provider models.MullvadProvider, protocol models.NetworkProtocol, customPort uint16) (connections []models.OpenVPNConnection, err error)
+	GetOpenVPNConnections(country models.MullvadCountry, city models.MullvadCity, provider models.MullvadProvider, protocol models.NetworkProtocol, customPort uint16, targetIP net.IP) (connections []models.OpenVPNConnection, err error)
 	BuildConf(connections []models.OpenVPNConnection, verbosity, uid, gid int, root bool) (err error)
 }
 

internal/params/openvpn.go

@@ -1,6 +1,9 @@
 package params
 
 import (
+	"fmt"
+	"net"
+
 	libparams "github.com/qdm12/golibs/params"
 	"github.com/qdm12/private-internet-access-docker/internal/models"
 )
@@ -45,3 +48,18 @@ func (p *paramsReader) GetOpenVPNVerbosity() (verbosity int, err error) {
 func (p *paramsReader) GetOpenVPNRoot() (root bool, err error) {
 	return p.envParams.GetYesNo("OPENVPN_ROOT", libparams.Default("no"))
 }
+
+// GetTargetIP obtains the IP address to choose from the list of IP addresses
+// available for a particular region, from the environment variable
+// OPENVPN_TARGET_IP
+func (p *paramsReader) GetTargetIP() (ip net.IP, err error) {
+	s, err := p.envParams.GetEnv("OPENVPN_TARGET_IP")
+	if len(s) == 0 {
+		return nil, nil
+	}
+	ip = net.ParseIP(s)
+	if ip == nil {
+		return nil, fmt.Errorf("target IP address %q is not valid", s)
+	}
+	return ip, nil
+}

internal/params/params.go

@@ -37,6 +37,7 @@ type ParamsReader interface {
 	GetNetworkProtocol() (protocol models.NetworkProtocol, err error)
 	GetOpenVPNVerbosity() (verbosity int, err error)
 	GetOpenVPNRoot() (root bool, err error)
+	GetTargetIP() (ip net.IP, err error)
 
 	// PIA getters
 	GetPortForwarding() (activated bool, err error)

internal/pia/conf.go

@@ -2,6 +2,7 @@ package pia
 
 import (
 	"fmt"
+	"net"
 	"strings"
 
 	"github.com/qdm12/golibs/files"
@@ -9,7 +10,7 @@ import (
 	"github.com/qdm12/private-internet-access-docker/internal/models"
 )
 
-func (c *configurator) GetOpenVPNConnections(region models.PIARegion, protocol models.NetworkProtocol, encryption models.PIAEncryption) (connections []models.OpenVPNConnection, err error) {
+func (c *configurator) GetOpenVPNConnections(region models.PIARegion, protocol models.NetworkProtocol, encryption models.PIAEncryption, targetIP net.IP) (connections []models.OpenVPNConnection, err error) {
 	geoMapping := constants.PIAGeoToSubdomainMapping()
 	var subdomain string
 	for r, s := range geoMapping {
@@ -24,10 +25,24 @@ func (c *configurator) GetOpenVPNConnections(region models.PIARegion, protocol m
 	if err != nil {
 		return nil, err
 	}
-	IPs, err := c.lookupIP(subdomain + ".privateinternetaccess.com")
+	hostname := subdomain + ".privateinternetaccess.com"
+	IPs, err := c.lookupIP(hostname)
 	if err != nil {
 		return nil, err
 	}
+	if targetIP != nil {
+		found := false
+		for i := range IPs {
+			if IPs[i].Equal(targetIP) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return nil, fmt.Errorf("target IP address %q not found from IP addresses resolved from %s", targetIP, hostname)
+		}
+		IPs = []net.IP{targetIP}
+	}
 	var port uint16
 	switch protocol {
 	case constants.TCP:

internal/pia/pia.go

@@ -17,7 +17,7 @@ const logPrefix = "PIA configurator"
 // Configurator contains methods to download, read and modify the openvpn configuration to connect as a client
 type Configurator interface {
 	GetOpenVPNConnections(region models.PIARegion, protocol models.NetworkProtocol,
-		encryption models.PIAEncryption) (connections []models.OpenVPNConnection, err error)
+		encryption models.PIAEncryption, targetIP net.IP) (connections []models.OpenVPNConnection, err error)
 	BuildConf(connections []models.OpenVPNConnection, encryption models.PIAEncryption, verbosity, uid, gid int, root bool) (err error)
 	GetPortForward() (port uint16, err error)
 	WritePortForward(filepath models.Filepath, port uint16) (err error)

internal/settings/openvpn.go

@@ -2,6 +2,7 @@ package settings
 
 import (
 	"fmt"
+	"net"
 	"strings"
 
 	"github.com/qdm12/private-internet-access-docker/internal/models"
@@ -13,6 +14,7 @@ type OpenVPN struct {
 	NetworkProtocol models.NetworkProtocol
 	Verbosity       int
 	Root            bool
+	TargetIP        net.IP
 }
 
 // GetOpenVPNSettings obtains the OpenVPN settings using the params functions
@@ -26,6 +28,13 @@ func GetOpenVPNSettings(params params.ParamsReader) (settings OpenVPN, err error
 		return settings, err
 	}
 	settings.Root, err = params.GetOpenVPNRoot()
+	if err != nil {
+		return settings, err
+	}
+	settings.TargetIP, err = params.GetTargetIP()
+	if err != nil {
+		return settings, err
+	}
 	return settings, nil
 }
 
@@ -39,6 +48,7 @@ func (o *OpenVPN) String() string {
 		"Network protocol: " + string(o.NetworkProtocol),
 		"Verbosity level: " + fmt.Sprintf("%d", o.Verbosity),
 		"Run as root: " + runAsRoot,
+		"Target IP address: " + o.TargetIP.String(),
 	}
 	return strings.Join(settingsList, "\n|--")
 }