link, veth: remove useless call to retrieve ethtool strings

It's not needed for retrieving the veth peer ifindex, and we already
get the set count via earlier ETHTOOL_GSSET_INFO call. Both are copying
veth_get_sset_count() up to user space in veth case (which is the only
user of this anyway).

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

ioctl_linux.go

@@ -56,14 +56,6 @@ type ethtoolSset struct {
 	data     [1]uint32
 }
 
-// ethtoolGstrings is string set for data tagging
-type ethtoolGstrings struct {
-	cmd       uint32
-	stringSet uint32
-	length    uint32
-	data      [32]byte
-}
-
 type ethtoolStats struct {
 	cmd    uint32
 	nStats uint32

link_linux.go

@@ -2933,20 +2933,9 @@ func VethPeerIndex(link *Veth) (int, error) {
 		return -1, fmt.Errorf("SIOCETHTOOL request for %q failed, errno=%v", link.Attrs().Name, errno)
 	}
 
-	gstrings := &ethtoolGstrings{
-		cmd:       ETHTOOL_GSTRINGS,
-		stringSet: ETH_SS_STATS,
-		length:    sSet.data[0],
-	}
-	ifreq.Data = uintptr(unsafe.Pointer(gstrings))
-	_, _, errno = syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), SIOCETHTOOL, uintptr(unsafe.Pointer(ifreq)))
-	if errno != 0 {
-		return -1, fmt.Errorf("SIOCETHTOOL request for %q failed, errno=%v", link.Attrs().Name, errno)
-	}
-
 	stats := &ethtoolStats{
 		cmd:    ETHTOOL_GSTATS,
-		nStats: gstrings.length,
+		nStats: sSet.data[0],
 	}
 	ifreq.Data = uintptr(unsafe.Pointer(stats))
 	_, _, errno = syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), SIOCETHTOOL, uintptr(unsafe.Pointer(ifreq)))