Chore: update stack icmp

stack/icmp.go

@@ -1,10 +1,8 @@
 package stack
 
 import (
-	"fmt"
-	"net"
-
 	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
 )
 
 func withICMPHandler() Option {
@@ -13,28 +11,14 @@ func withICMPHandler() Option {
 		// This will handle all incoming ICMP packets.
 		s.SetRouteTable([]tcpip.Route{
 			{
-				Destination: mustSubnet("0.0.0.0/0"),
+				Destination: header.IPv4EmptySubnet,
 				NIC:         s.nicID,
 			},
 			{
-				Destination: mustSubnet("::/0"),
+				Destination: header.IPv6EmptySubnet,
 				NIC:         s.nicID,
 			},
 		})
 		return nil
 	}
 }
-
-// mustSubnet returns tcpip.Subnet from CIDR string.
-func mustSubnet(s string) tcpip.Subnet {
-	_, ipNet, err := net.ParseCIDR(s)
-	if err != nil {
-		panic(fmt.Errorf("parse CIDR: %w", err))
-	}
-
-	subnet, err := tcpip.NewSubnet(tcpip.Address(ipNet.IP), tcpip.AddressMask(ipNet.Mask))
-	if err != nil {
-		panic(fmt.Errorf("new subnet: %w", err))
-	}
-	return subnet
-}