⚠️ change multicast ttl

Author: Yuzz1e

go.mod

@@ -11,4 +11,7 @@ require (
 	gopkg.in/yaml.v3 v3.0.1
 )
 
-require golang.org/x/net v0.23.0 // indirect
+require (
+	golang.org/x/net v0.23.0 // indirect
+	golang.org/x/sys v0.18.0 // indirect
+)

go.sum

@@ -10,6 +10,8 @@ github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 golang.org/x/net v0.23.0 h1:7EYJ93RZ9vYSZAIb2x3lnuvqO5zneoD6IvWjuhfxjTs=
 golang.org/x/net v0.23.0/go.mod h1:JKghWKKOSdJwpW2GEx0Ja7fmaKnMsbu+MWVZTokSYmg=
+golang.org/x/sys v0.18.0 h1:DBdB3niSjOA/O0blCZBqDefyWNYveAYMNF1Wum0DYQ4=
+golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=

internal/app/publish/publisher.go

@@ -1,10 +1,12 @@
 package publish
 
 import (
-	"github.com/RoboCup-SSL/ssl-game-controller/internal/app/state"
-	"google.golang.org/protobuf/proto"
 	"log"
 	"net"
+
+	"github.com/RoboCup-SSL/ssl-game-controller/internal/app/state"
+	"golang.org/x/net/ipv4"
+	"google.golang.org/protobuf/proto"
 )
 
 const maxDatagramSize = 8192
@@ -51,6 +53,11 @@ func (p *Publisher) connect() bool {
 			log.Printf("Could not connect to '%v': %v", addr, err)
 			continue
 		}
+		conn2 := ipv4.NewPacketConn(conn)
+		err = conn2.SetMulticastTTL(32)
+		if err != nil {
+			log.Printf("Could not set TTL to 32: %v", err)
+		}
 
 		if err := conn.SetWriteBuffer(maxDatagramSize); err != nil {
 			log.Printf("Could not set write buffer to %v.", maxDatagramSize)