Add ping proxy support

stack_system_packet.go

@@ -5,6 +5,7 @@ import (
 	"syscall"
 
 	"github.com/sagernet/sing-tun/internal/gtcpip/header"
+	"github.com/sagernet/sing/common"
 )
 
 func PacketIPVersion(packet []byte) int {
@@ -13,6 +14,7 @@ func PacketIPVersion(packet []byte) int {
 
 func PacketFillHeader(packet []byte, ipVersion int) {
 	if PacketOffset > 0 {
+		common.ClearArray(packet[:3])
 		switch ipVersion {
 		case header.IPv4Version:
 			packet[3] = syscall.AF_INET