Fix error use of WriteTo with pre-connected connection

nextmn · Dec 10, 2024 · 788cba7 · 788cba7
1 parent bb992be
commit 788cba7
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Showing 3 changed files with 13 additions and 2 deletions.
diff --git a/pfcp/api/entity_interface.go b/pfcp/api/entity_interface.go
@@ -6,10 +6,13 @@
 package api
 
 import (
+	"net/netip"
+
 	"github.com/wmnsk/go-pfcp/ie"
 )
 
 type PFCPEntityInterface interface {
+	ListenAddr() netip.Addr
 	IsUserPlane() bool
 	IsControlPlane() bool
 	NodeID() *ie.IE

diff --git a/pfcp/entity.go b/pfcp/entity.go
@@ -85,6 +85,10 @@ func (e *PFCPEntity) closePfcpConn() error {
 	return nil
 }
 
+func (e *PFCPEntity) ListenAddr() netip.Addr {
+	return e.listenAddr
+}
+
 func (e *PFCPEntity) Options() api.EntityOptionsInterface {
 	return e.options
 }

diff --git a/pfcp/peer.go b/pfcp/peer.go
@@ -63,7 +63,7 @@ func newPFCPPeer(srv api.PFCPEntityInterface, nodeID *ie.IE, kind string) (peer
 
 	raddr := net.UDPAddrFromAddrPort(netip.AddrPortFrom(ips[0], pfcputil.PFCP_PORT))
 
-	conn, err := net.DialUDP("udp", nil, raddr)
+	conn, err := net.ListenUDP("udp", net.UDPAddrFromAddrPort(netip.AddrPortFrom(srv.ListenAddr(), 0)))
 	if err != nil {
 		return nil, err
 	}
@@ -112,11 +112,15 @@ func (peer *PFCPPeer) startLoop() {
 
 func (peer *PFCPPeer) loopUnwrapped() {
 	b := make([]byte, pfcputil.DEFAULT_MTU) // TODO: detect MTU for interface instead of using DEFAULT_MTU
-	n, _, err := peer.conn.ReadFromUDP(b)
+	n, addr, err := peer.conn.ReadFromUDP(b)
 	if err != nil {
 		// socket has been closed
 		return
 	}
+	if addr.String() != peer.udpAddr.String() {
+		// peer usurpated
+		return
+	}
 	// Processing of message in a new thread to avoid blocking
 	go func(msgArray []byte, size int, e *PFCPPeer) {
 		msg, err := message.ParseHeader(msgArray[:size])