Add auto setup support for DD-WRT

install.sh

@@ -172,6 +172,8 @@ detect_os() {
         ASUSWRT-Merlin)
             echo "asuswrt-merlin"; return 0
             ;;
+        DD-WRT)
+            echo "ddwrt"; return 0
         esac
         ;;
     Darwin)
@@ -328,6 +330,29 @@ uninstall_openwrt() {
     opkg remove nextdns
 }
 
+install_ddwrt() {
+    if [ "$(nvram get enable_jffs2)" = "0" ]; then
+        log_error "JFFS support not enabled"
+        log_info "To enabled JFFS:"
+        log_info " 1. On the router web page click on Administration."
+        log_info " 2. Scroll down until you see JFFS2 Support section."
+        log_info " 3. Click Enable JFFS."
+        log_info " 4. Click Save."
+        log_info " 5. Wait couple seconds, then click Apply."
+        log_info " 6. Wait again. Go back to the Enable JFFS section, and enable Clean JFFS."
+        log_info " 7. Do not click Save. Click Apply instead."
+        log_info " 8. Wait till you get the web-GUI back, then disable Clean JFFS again."
+        log_info " 9. Click Save."
+        log_info "10. Relaunch this installer."
+        exit 1
+    fi
+    install_bin
+}
+
+uninstall_ddwrt() {
+    uninstall_bin
+}
+
 install_brew() {
     silent_exec brew install nextdns/tap/nextdns
 }
@@ -381,6 +406,9 @@ install_type() {
     asuswrt-merlin|edgeos)
         echo "bin"
         ;;
+    ddwrt)
+        echo "ddwrt"
+        ;;
     darwin)
         if [ -x /usr/local/bin/brew ]; then
             echo "brew"

router/ddwrt/setup.go

@@ -0,0 +1,106 @@
+package ddwrt
+
+import (
+	"bytes"
+	"fmt"
+	"os/exec"
+	"strings"
+	"text/template"
+
+	"github.com/nextdns/nextdns/config"
+	"github.com/nextdns/nextdns/router/internal"
+)
+
+type Router struct {
+	ListenPort      string
+	ClientReporting bool
+	savedParams     []string
+}
+
+func New() (*Router, bool) {
+	if b, err := exec.Command("uname", "-o").Output(); err != nil ||
+		!strings.HasPrefix(string(b), "DD-WRT") {
+		return nil, false
+	}
+	return &Router{
+		ListenPort: "5342",
+	}, true
+}
+
+func (r *Router) Configure(c *config.Config) {
+	c.Listen = "127.0.0.1:" + r.ListenPort
+	r.ClientReporting = c.ReportClientInfo
+}
+
+func (r *Router) Setup() error {
+	t, err := template.New("").Parse(tmpl)
+	if err != nil {
+		return err
+	}
+
+	var buf bytes.Buffer
+	if err = t.Execute(&buf, r); err != nil {
+		return err
+	}
+
+	// Save nvram values so we can restore them.
+	if r.savedParams, err = internal.NVRAM(
+		"dns_dnsmasq",
+		"dnsmasq_options",
+		"dns_crypt",
+		"dnssec",
+		"dnsmasq_no_dns_rebind",
+		"dnsmasq_add_mac"); err != nil {
+		return err
+	}
+
+	// Configure the firmware:
+	// * Add dnsmasq options to route queries to nextdns
+	// * DNS rebinding is disabled, as DNS blocking uses 0.0.0.0 to block domains.
+	//   The rebinding protection can be setup and enforced at NextDNS level.
+	// * DNSCrypt is disabled as it would conflict.
+	// * DNSSEC validation is disabled as when a DNSSEC supported domain is blocked,
+	//   the validation will fail as blocking alters the response. NextDNS takes care
+	//   of DNS validation for non blocked queries.
+	// * DNS over TLS is disabled so stubby does not run for nothing.
+	if err := internal.SetNVRAM(
+		"dns_dnsmasq=1",
+		"dnsmasq_options="+buf.String(),
+		"dns_crypt=0",
+		"dnssec=0",
+		"dnsmasq_no_dns_rebind=0",
+		"dnsmasq_add_mac=0"); err != nil {
+		return err
+	}
+
+	// Restart dnsmasq service to apply changes.
+	return restartDNSMasq()
+}
+
+func (r *Router) Restore() error {
+	// Restore previous settings.
+	if err := internal.SetNVRAM(r.savedParams...); err != nil {
+		return err
+	}
+	// Restart dnsmasq service to apply changes.
+	return restartDNSMasq()
+}
+
+func restartDNSMasq() error {
+	if err := exec.Command("stopservice", "dnsmasq").Run(); err != nil {
+		return fmt.Errorf("stopservice dnsmasq: %v", err)
+	}
+	if err := exec.Command("startservice", "dnsmasq").Run(); err != nil {
+		return fmt.Errorf("startservice dnsmasq: %v", err)
+	}
+	return nil
+}
+
+var tmpl = `# Configuration generated by NextDNS
+no-resolv
+server=127.0.0.1#{{.ListenPort}}
+{{- if .ClientReporting}}
+add-mac
+add-subnet=32,128
+{{- end}}
+`