diff options
Diffstat (limited to 'pkg/tcpip')
| -rw-r--r-- | pkg/tcpip/header/ipv4.go | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/pkg/tcpip/header/ipv4.go b/pkg/tcpip/header/ipv4.go index 7e32b31b4..3d465e28a 100644 --- a/pkg/tcpip/header/ipv4.go +++ b/pkg/tcpip/header/ipv4.go @@ -374,8 +374,14 @@ func (b IPv4) Encode(i *IPv4Fields) { if hdrLen > len(b) { panic(fmt.Sprintf("encode received %d bytes, wanted >= %d", len(b), hdrLen)) } - if aLen != copy(b[options:], i.Options) { - _ = copy(b[options+len(i.Options):options+aLen], []byte{0, 0, 0, 0}) + opts := b[options:] + // This avoids bounds checks on the next line(s) which would happen even + // if there's no work to do. + if n := copy(opts, i.Options); n != aLen { + padding := opts[n:][:aLen-n] + for i := range padding { + padding[i] = 0 + } } } b.SetHeaderLength(uint8(hdrLen)) |