keksvpn/vendor/github.com/mdlayher/netlink/align.go

38 lines
1.1 KiB
Go
Raw Normal View History

2022-02-27 03:22:11 +00:00
package netlink
import "unsafe"
// Functions and values used to properly align netlink messages, headers,
// and attributes. Definitions taken from Linux kernel source.
// #define NLMSG_ALIGNTO 4U
const nlmsgAlignTo = 4
// #define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
func nlmsgAlign(len int) int {
return ((len) + nlmsgAlignTo - 1) & ^(nlmsgAlignTo - 1)
}
// #define NLMSG_LENGTH(len) ((len) + NLMSG_HDRLEN)
func nlmsgLength(len int) int {
return len + nlmsgHeaderLen
}
// #define NLMSG_HDRLEN ((int) NLMSG_ALIGN(sizeof(struct nlmsghdr)))
var nlmsgHeaderLen = nlmsgAlign(int(unsafe.Sizeof(Header{})))
// #define NLA_ALIGNTO 4
const nlaAlignTo = 4
// #define NLA_ALIGN(len) (((len) + NLA_ALIGNTO - 1) & ~(NLA_ALIGNTO - 1))
func nlaAlign(len int) int {
return ((len) + nlaAlignTo - 1) & ^(nlaAlignTo - 1)
}
// Because this package's Attribute type contains a byte slice, unsafe.Sizeof
// can't be used to determine the correct length.
const sizeofAttribute = 4
// #define NLA_HDRLEN ((int) NLA_ALIGN(sizeof(struct nlattr)))
var nlaHeaderLen = nlaAlign(sizeofAttribute)