nebula/udp/udp_linux_32.go

//go:build linux && (386 || amd64p32 || arm || mips || mipsle) && !android && !e2e_testing
// +build linux
// +build 386 amd64p32 arm mips mipsle
// +build !android
// +build !e2e_testing

package udp

import (
	"golang.org/x/sys/unix"
)

type iovec struct {
	Base *byte
	Len  uint32
}

type msghdr struct {
	Name       *byte
	Namelen    uint32
	Iov        *iovec
	Iovlen     uint32
	Control    *byte
	Controllen uint32
	Flags      int32
}

type rawMessage struct {
	Hdr msghdr
	Len uint32
}

func (u *StdConn) PrepareRawMessages(n int, bufSize int) ([]rawMessage, [][]byte, [][]byte) {
	if bufSize <= 0 {
		bufSize = MTU
	}
	msgs := make([]rawMessage, n)
	buffers := make([][]byte, n)
	names := make([][]byte, n)

	for i := range msgs {
		buffers[i] = make([]byte, bufSize)
		names[i] = make([]byte, unix.SizeofSockaddrInet6)

		vs := []iovec{
			{Base: &buffers[i][0], Len: uint32(len(buffers[i]))},
		}

		msgs[i].Hdr.Iov = &vs[0]
		msgs[i].Hdr.Iovlen = uint32(len(vs))

		msgs[i].Hdr.Name = &names[i][0]
		msgs[i].Hdr.Namelen = uint32(len(names[i]))
	}

	return msgs, buffers, names
}

func setRawMessageControl(msg *rawMessage, buf []byte) {
	if len(buf) == 0 {
		msg.Hdr.Control = nil
		msg.Hdr.Controllen = 0
		return
	}
	msg.Hdr.Control = &buf[0]
	msg.Hdr.Controllen = uint32(len(buf))
}

func getRawMessageControlLen(msg *rawMessage) int {
	return int(msg.Hdr.Controllen)
}

func getRawMessageFlags(msg *rawMessage) int {
	return int(msg.Hdr.Flags)
}

func setCmsgLen(h *unix.Cmsghdr, l int) {
	h.Len = uint32(l)
}