Fix: Support for IPv6 ( issue #2 ) and backup IPv4 DNS, ability to override DNS option inside client configs

Author: AndrianBdn

README.md

@@ -93,7 +93,7 @@ client configuration files.
 
 `ClientRoute` - AllowedIPs for client config
 
-`ClientDNS` - DNS for client config
+`ClientDNS` - DNS configuration value for all clients
 
 `ClientServerEndpoint` - Endpoint for client config
 
@@ -105,7 +105,10 @@ client configuration files.
 
 Contains `ClientRoute` that overrides the one from server config.
 
-`MTU` - Override server MTU with a different value for this client
+`MTU` - Override server MTU with a different value for this client. Set to -1 to omit MTU from this WireGuard client config.
+
+`DNS` - Override server `ClientDNS` setting for all clients. Specify a comma separated IP list. 
+Set to `no` or `none` to omit DNS from this WireGuard client config.
 
 Client configuration files contain `PrivateKey` field. 
 If you find it unacceptable, you can remove it from the file after you exported 

backend/client.go

@@ -21,6 +21,7 @@ type Client struct {
 	PrivateKey  string
 	ClientRoute string
 	MTU         int
+	DNS         string
 }
 
 func ReadClient(dir string, fileName string, ipNum int, name string) (*Client, error) {

backend/generator.go

@@ -44,8 +44,12 @@ func (c *Client) generateClientConfig(server *Server, w io.Writer) error {
 	_, _ = fmt.Fprintln(w, "PrivateKey =", c.PrivateKey)
 	_, _ = fmt.Fprintln(w, "Address =", c.AllowedIps(server))
 
-	if server.ClientDNS != "" {
-		_, _ = fmt.Fprintln(w, "DNS =", server.ClientDNS)
+	if c.DNS != "no" && c.DNS != "none" {
+		if c.DNS == "" && server.ClientDNS != "" {
+			_, _ = fmt.Fprintln(w, "DNS =", server.ClientDNS)
+		} else if c.DNS != "" {
+			_, _ = fmt.Fprintln(w, "DNS =", c.DNS)
+		}
 	}
 
 	_, _ = fmt.Fprintln(w, "\n[Peer]")
@@ -65,9 +69,9 @@ func (c *Client) generateClientConfig(server *Server, w io.Writer) error {
 		_, _ = fmt.Fprintln(w, "PersistentKeepalive =", server.ClientPersistentKeepalive)
 	}
 
-	if c.MTU != 0 {
+	if c.MTU > 0 {
 		_, _ = fmt.Fprintln(w, "MTU =", c.MTU)
-	} else if server.MTU != 0 {
+	} else if server.MTU != 0 && c.MTU == 0 {
 		_, _ = fmt.Fprintln(w, "MTU =", server.MTU)
 	}
 

backend/server.go

@@ -24,7 +24,7 @@ type ServerBlueprint struct {
 	Nat6          bool
 	Net4          string
 	Net6          string
-	DNS           string
+	DNS           []string
 }
 
 type Server struct {
@@ -108,7 +108,7 @@ func NewServerWithBlueprint(b ServerBlueprint) *Server {
 		}
 	}
 
-	s.ClientDNS = b.DNS
+	s.ClientDNS = dnsString(b.DNS, b.Net6 != "" && b.Nat6)
 	s.ClientServerEndpoint = b.Endpoint
 	s.ClientPersistentKeepalive = 42
 	return &s

backend/utils.go

@@ -61,3 +61,15 @@ func concatIfNotEmpty(str string, add string) string {
 	}
 	return str
 }
+
+func dnsString(dns []string, ipv6 bool) string {
+	var dnsStr string
+	for _, d := range dns {
+		if strings.Contains(d, ":") && !ipv6 {
+			continue
+		}
+		dnsStr = concatIfNotEmpty(dnsStr, ", ")
+		dnsStr += d
+	}
+	return dnsStr
+}

wizard/dns.go

@@ -0,0 +1,8 @@
+package wizard
+
+var dnsDict = map[string][]string{
+	"google":     {"2001:4860:4860::8888", "2001:4860:4860::8844", "8.8.8.8", "8.8.4.4"},
+	"cloudflare": {"2606:4700:4700::1111", "2606:4700:4700::1001", "1.1.1.1", "1.0.0.1"},
+	"quad9":      {"2620:fe::fe", "2620:fe::9", "9.9.9.9", "149.112.112.112"},
+	"opendns":    {"2620:119:35::35", "2620:119:53::53", "208.67.222.222", "208.67.220.220"},
+}

wizard/wizard.go

@@ -50,9 +50,22 @@ func (m RootModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		m.sSize = msg
 	}
 
+	if do, m, c := m.WizardStateUpdate(msg); do {
+		return m, c
+	}
+
+	if m.currentModel != nil {
+		w, c := m.currentModel.Update(msg)
+		m.currentModel = w
+		return m, c
+	}
+	return m, nil
+}
+
+func (m RootModel) WizardStateUpdate(msg tea.Msg) (bool, tea.Model, tea.Cmd) {
 	if _, ok := msg.(welcomeScreenResult); ok {
 		m.currentModel = newInterfaceScreen(m.app, m.sSize)
-		return m, m.currentModel.Init()
+		return true, m, m.currentModel.Init()
 	}
 
 	if msg, ok := msg.(interfaceScreenResult); ok {
@@ -61,28 +74,29 @@ func (m RootModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 		portStep := newPortScreen(m.sSize)
 		m.currentModel = portStep
-		return m, portStep.Init()
+		return true, m, portStep.Init()
 	}
 
 	if msg, ok := msg.(portStepResult); ok {
 		m.blueprint.Port = uint16(msg)
 
 		endStep := newEndpointStep(m.sSize)
 		m.currentModel = endStep
-		return m, endStep.Init()
+		return true, m, endStep.Init()
 	}
 
 	if msg, ok := msg.(endpointStepResult); ok {
 		m.blueprint.Endpoint = string(msg)
 		netStep := newNetScreen(m.sSize)
 		m.currentModel = netStep
-		return m, netStep.Init()
+		return true, m, netStep.Init()
 	}
 
 	if msg, ok := msg.(netStepResult); ok {
 		m.blueprint.Net4 = msg.net4
 		m.blueprint.Net6 = msg.net6
-		return m.presentNatDialog()
+		m, c := m.presentNatDialog()
+		return true, m, c
 	}
 
 	if msg, ok := msg.(optScreenResult); ok {
@@ -99,14 +113,15 @@ func (m RootModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 				m.blueprint.Nat6 = false
 			}
 
-			return m.presentDNSDialog()
+			m, c := m.presentDNSDialog()
+			return true, m, c
 		}
 
 		if msg.id == optIdDNS {
-			m.blueprint.DNS = msg.result.id
+			m.blueprint.DNS = dnsDict[msg.result.id]
 			doneStep := newDoneScreen(m.app, m.sSize, m.blueprint)
 			m.currentModel = doneStep
-			return m, doneStep.Init()
+			return true, m, doneStep.Init()
 		}
 
 	}
@@ -118,27 +133,22 @@ func (m RootModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			// extra step to check NAT and setup systemd
 			rootLinux := newLinuxMoreScreen(m.app, m.sSize, m.blueprint)
 			m.currentModel = rootLinux
-			return m, rootLinux.Init()
+			return true, m, rootLinux.Init()
 		}
 
-		return m, func() tea.Msg {
+		return true, m, func() tea.Msg {
 			return Done{InterfaceName: m.blueprint.InterfaceName}
 		}
 	}
 
 	if _, ok := msg.(linuxMoreDone); ok {
 		m.currentModel = nil
-		return m, func() tea.Msg {
+		return true, m, func() tea.Msg {
 			return Done{InterfaceName: m.blueprint.InterfaceName}
 		}
 	}
 
-	if m.currentModel != nil {
-		w, c := m.currentModel.Update(msg)
-		m.currentModel = w
-		return m, c
-	}
-	return m, nil
+	return false, nil, nil
 }
 
 func (m RootModel) View() string {
@@ -168,10 +178,10 @@ func (m RootModel) presentNatDialog() (tea.Model, tea.Cmd) {
 
 func (m RootModel) presentDNSDialog() (tea.Model, tea.Cmd) {
 	opts := []opt{
-		{"1.1.1.1", "Use Cloudflare DNS https://1.1.1.1"},
-		{"8.8.8.8", "Use Google DNS https://developers.google.com/speed/public-dns"},
-		{"9.9.9.9", "Use Quad9 DNS https://www.quad9.net/"},
-		{"208.67.222.222", "Use OpenDNS https://use.opendns.com/"},
+		{"cloudflare", "Use Cloudflare DNS https://1.1.1.1"},
+		{"google", "Use Google DNS https://developers.google.com/speed/public-dns"},
+		{"quad9", "Use Quad9 DNS https://www.quad9.net/"},
+		{"opendns", "Use OpenDNS https://use.opendns.com/"},
 	}
 
 	// shuffle options, so no service will get default treatment (on avarage)