new: net.probe is now be able to actively discover mDNS services

modules/net_probe/net_probe.go

@@ -116,6 +116,10 @@ func (mod *Prober) Start() error {
 			mod.Fatal("%s", err)
 		}
 
+		if mod.probes.MDNS {
+			go mod.mdnsProber()
+		}
+
 		fromIP := mod.Session.Interface.IP
 		fromHW := mod.Session.Interface.HW
 		addresses := list.Expand()

modules/net_probe/net_probe_mdns.go

@@ -1,11 +1,31 @@
 package net_probe
 
 import (
+	"fmt"
+	"io/ioutil"
+	"log"
 	"net"
+	"sync"
+	"time"
 
 	"github.com/bettercap/bettercap/packets"
+
+	"github.com/hashicorp/mdns"
 )
 
+var services = []string{
+	"_hap._tcp.local",
+	"_homekit._tcp.local",
+	"_airplay._tcp.local",
+	"_raop._tcp.local",
+	"_sleep-proxy._udp.local",
+	"_companion-link._tcp.local",
+	"_googlezone._tcp.local",
+	"_googlerpc._tcp.local",
+	"_googlecast._tcp.local",
+	"local",
+}
+
 func (mod *Prober) sendProbeMDNS(from net.IP, from_hw net.HardwareAddr) {
 	err, raw := packets.NewMDNSProbe(from, from_hw)
 	if err != nil {
@@ -17,3 +37,59 @@ func (mod *Prober) sendProbeMDNS(from net.IP, from_hw net.HardwareAddr) {
 		mod.Debug("sent %d bytes of MDNS probe", len(raw))
 	}
 }
+
+func (mod *Prober) mdnsProber() {
+	mod.waitGroup.Add(1)
+	defer mod.waitGroup.Done()
+
+	mod.Debug("mdns prober started")
+	defer mod.Debug("mdns.prober stopped")
+
+	log.SetOutput(ioutil.Discard)
+
+	ch := make(chan *mdns.ServiceEntry)
+	wait := sync.WaitGroup{}
+
+	defer close(ch)
+
+	go func(c chan *mdns.ServiceEntry) {
+		mod.Debug("mdns channel read started")
+		defer mod.Debug("mdns channel read stopped")
+
+		for entry := range c {
+			if host := mod.Session.Lan.GetByIp(entry.AddrV4.String()); host != nil {
+				meta := make(map[string]string)
+
+				meta["mdns:name"] = entry.Name
+				meta["mdns:hostname"] = entry.Host
+				meta["mdns:ipv4"] = entry.AddrV4.String()
+
+				if entry.AddrV6 != nil {
+					meta["mdns:ipv6"] = entry.AddrV6.String()
+				}
+
+				meta["mdns:port"] = fmt.Sprintf("%d", entry.Port)
+
+				host.OnMeta(meta)
+			} else {
+				mod.Debug("got mdns entry for known ip %s", entry.AddrV4)
+			}
+		}
+	}(ch)
+
+	for mod.Running() {
+		for _, svc := range services {
+			go func(svc string, w *sync.WaitGroup) {
+				w.Add(1)
+				defer w.Done()
+
+				params := mdns.DefaultParams(svc)
+				params.Entries = ch
+				params.Timeout = time.Duration(5) * time.Second
+
+				mdns.Query(params)
+			}(svc, &wait)
+		}
+		wait.Wait()
+	}
+}