From 59dc74ffbbbfe404b414b00dd6043af9133ecd23 Mon Sep 17 00:00:00 2001
From: Cuong Manh Le <cuong@windscribe.com>
Date: Tue, 25 Jul 2023 20:28:30 +0000
Subject: [PATCH] internal: record correct interfaces for queries from router
 on Firewalla

---
 internal/clientinfo/dhcp.go        | 23 +++++++++++--
 internal/router/dnsmasq/dnsmasq.go | 52 ++++++++++++++++++------------
 internal/router/router.go          | 10 ++++++
 3 files changed, 62 insertions(+), 23 deletions(-)

diff --git a/internal/clientinfo/dhcp.go b/internal/clientinfo/dhcp.go
index bcad26a..ad423bd 100644
--- a/internal/clientinfo/dhcp.go
+++ b/internal/clientinfo/dhcp.go
@@ -11,11 +11,12 @@ import (
 	"strings"
 	"sync"
 
-	"github.com/Control-D-Inc/ctrld"
+	"github.com/fsnotify/fsnotify"
 	"tailscale.com/net/interfaces"
 	"tailscale.com/util/lineread"
 
-	"github.com/fsnotify/fsnotify"
+	"github.com/Control-D-Inc/ctrld"
+	"github.com/Control-D-Inc/ctrld/internal/router"
 )
 
 type dhcp struct {
@@ -279,4 +280,22 @@ func (d *dhcp) addSelf() {
 			}
 		}
 	})
+	for _, netIface := range router.SelfInterfaces() {
+		mac := netIface.HardwareAddr.String()
+		if mac == "" {
+			return
+		}
+		d.mac2name.Store(mac, hostname)
+		addrs, _ := netIface.Addrs()
+		for _, addr := range addrs {
+			ipNet, ok := addr.(*net.IPNet)
+			if !ok {
+				continue
+			}
+			ip := ipNet.IP
+			d.mac.LoadOrStore(ip.String(), mac)
+			d.ip.LoadOrStore(mac, ip.String())
+			d.ip2name.Store(ip.String(), hostname)
+		}
+	}
 }
diff --git a/internal/router/dnsmasq/dnsmasq.go b/internal/router/dnsmasq/dnsmasq.go
index 0b051aa..a25f564 100644
--- a/internal/router/dnsmasq/dnsmasq.go
+++ b/internal/router/dnsmasq/dnsmasq.go
@@ -13,7 +13,7 @@ import (
 const ConfigContentTmpl = `# GENERATED BY ctrld - DO NOT MODIFY
 no-resolv
 {{- range .Upstreams}}
-server={{ .Ip }}#{{ .Port }}
+server={{ .IP }}#{{ .Port }}
 {{- end}}
 {{- if .SendClientInfo}}
 add-mac
@@ -36,7 +36,7 @@ if [ -n "$pid" ] && [ -f "/proc/${pid}/cmdline" ]; then
   # use ctrld as upstream
   pc_delete "server=" "$config_file"
   {{- range .Upstreams}}
-  pc_append "server={{ .Ip }}#{{ .Port }}" "$config_file"
+  pc_append "server={{ .IP }}#{{ .Port }}" "$config_file"
   {{- end}}
   {{- if .SendClientInfo}}
   pc_append "add-mac" "$config_file"                # add client mac
@@ -56,7 +56,7 @@ fi
 `
 
 type Upstream struct {
-	Ip   string
+	IP   string
 	Port int
 }
 
@@ -69,7 +69,7 @@ func ConfTmpl(tmplText string, cfg *ctrld.Config) (string, error) {
 	if ip == "0.0.0.0" || ip == "::" || ip == "" {
 		ip = "127.0.0.1"
 	}
-	upstreams := []Upstream{{Ip: ip, Port: listener.Port}}
+	upstreams := []Upstream{{IP: ip, Port: listener.Port}}
 	return confTmpl(tmplText, upstreams, cfg.HasUpstreamSendClientInfo())
 }
 
@@ -97,25 +97,35 @@ func confTmpl(tmplText string, upstreams []Upstream, sendClientInfo bool) (strin
 }
 
 func firewallaUpstreams(port int) []Upstream {
-	matches, err := filepath.Glob("/home/pi/firerouter/etc/dnsmasq.dns.*.conf")
-	if err != nil {
-		return nil
-	}
-	upstreams := make([]Upstream, 0, len(matches))
-	for _, match := range matches {
-		// Trim prefix and suffix to get the iface name only.
-		ifaceName := strings.TrimSuffix(strings.TrimPrefix(match, "/home/pi/firerouter/etc/dnsmasq.dns."), ".conf")
-		if netIface, _ := net.InterfaceByName(ifaceName); netIface != nil {
-			addrs, _ := netIface.Addrs()
-			for _, addr := range addrs {
-				if netIP, ok := addr.(*net.IPNet); ok && netIP.IP.To4() != nil {
-					upstreams = append(upstreams, Upstream{
-						Ip:   netIP.IP.To4().String(),
-						Port: port,
-					})
-				}
+	ifaces := FirewallaSelfInterfaces()
+	upstreams := make([]Upstream, 0, len(ifaces))
+	for _, netIface := range ifaces {
+		addrs, _ := netIface.Addrs()
+		for _, addr := range addrs {
+			if netIP, ok := addr.(*net.IPNet); ok && netIP.IP.To4() != nil {
+				upstreams = append(upstreams, Upstream{
+					IP:   netIP.IP.To4().String(),
+					Port: port,
+				})
 			}
 		}
 	}
 	return upstreams
 }
+
+// FirewallaSelfInterfaces returns list of interfaces that will be configured with default dnsmasq setup on Firewalla.
+func FirewallaSelfInterfaces() []*net.Interface {
+	matches, err := filepath.Glob("/home/pi/firerouter/etc/dnsmasq.dns.*.conf")
+	if err != nil {
+		return nil
+	}
+	ifaces := make([]*net.Interface, 0, len(matches))
+	for _, match := range matches {
+		// Trim prefix and suffix to get the iface name only.
+		ifaceName := strings.TrimSuffix(strings.TrimPrefix(match, "/home/pi/firerouter/etc/dnsmasq.dns."), ".conf")
+		if netIface, _ := net.InterfaceByName(ifaceName); netIface != nil {
+			ifaces = append(ifaces, netIface)
+		}
+	}
+	return ifaces
+}
diff --git a/internal/router/router.go b/internal/router/router.go
index 6cae16e..90882c9 100644
--- a/internal/router/router.go
+++ b/internal/router/router.go
@@ -188,6 +188,16 @@ func ServiceDependencies() []string {
 	return nil
 }
 
+// SelfInterfaces return list of *net.Interface that will be source of requests from router itself.
+func SelfInterfaces() []*net.Interface {
+	switch Name() {
+	case firewalla.Name:
+		return dnsmasq.FirewallaSelfInterfaces()
+	default:
+		return nil
+	}
+}
+
 func distroName() string {
 	switch {
 	case bytes.HasPrefix(unameO(), []byte("DD-WRT")):