Audit changes.

peer/multicast/receiver.go

@@ -7,18 +7,29 @@ import (
 	"net"
 	"net/netip"
 	"time"
+
+	"git.crumpington.com/lib/go/ratelimiter"
 )
 
 func Receiver(selfVPNIP netip.Addr, ch chan<- Packet) {
+	limiters := make([]*ratelimiter.Limiter, 256)
+	for i := range limiters {
+		limiters[i] = ratelimiter.New(ratelimiter.Config{
+			BurstLimit:   1,
+			FillPeriod:   broadcastInterval / 2,
+			MaxWaitCount: 0,
+		})
+	}
+
 	for {
-		if err := receiver(selfVPNIP, ch); err != nil {
+		if err := receiver(selfVPNIP, limiters, ch); err != nil {
 			log.Printf("[MCReader] %v", err)
 		}
 		time.Sleep(errorTimeout)
 	}
 }
 
-func receiver(selfVPNIP netip.Addr, ch chan<- Packet) error {
+func receiver(selfVPNIP netip.Addr, limiters []*ratelimiter.Limiter, ch chan<- Packet) error {
 	selfIP := selfVPNIP.As4()[3]
 
 	conn, err := net.ListenMulticastUDP("udp", nil, multicastAddr(selfVPNIP))
@@ -44,6 +55,9 @@ func receiver(selfVPNIP netip.Addr, ch chan<- Packet) error {
 		}
 
 		packet := unmarshal(buf[:n])
+		if err := limiters[packet.PeerIP].Limit(); err != nil {
+			continue
+		}
 
 		if packet.PeerIP == selfIP {
 			continue