mirror of https://github.com/jetkvm/kvm.git
86 lines
1.8 KiB
Go
86 lines
1.8 KiB
Go
package lldp
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import (
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"fmt"
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"net"
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"os"
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"syscall"
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"unsafe"
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"github.com/google/gopacket/afpacket"
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"golang.org/x/sys/unix"
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)
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const (
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afPacketBufferSize = 2 // in MiB
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afPacketSnaplen = 9216
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)
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func afPacketComputeSize(targetSizeMb int, snaplen int, pageSize int) (
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frameSize int, blockSize int, numBlocks int, err error) {
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if snaplen < pageSize {
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frameSize = pageSize / (pageSize / snaplen)
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} else {
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frameSize = (snaplen/pageSize + 1) * pageSize
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}
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// 128 is the default from the gopacket library so just use that
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blockSize = frameSize * 128
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numBlocks = (targetSizeMb * 1024 * 1024) / blockSize
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if numBlocks == 0 {
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return 0, 0, 0, fmt.Errorf("interface buffersize is too small")
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}
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return frameSize, blockSize, numBlocks, nil
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}
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func afPacketNewTPacket(ifName string) (*afpacket.TPacket, error) {
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szFrame, szBlock, numBlocks, err := afPacketComputeSize(
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afPacketBufferSize,
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afPacketSnaplen,
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os.Getpagesize())
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if err != nil {
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return nil, err
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}
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return afpacket.NewTPacket(
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afpacket.OptInterface(ifName),
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afpacket.OptFrameSize(szFrame),
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afpacket.OptBlockSize(szBlock),
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afpacket.OptNumBlocks(numBlocks),
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afpacket.OptAddVLANHeader(false),
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afpacket.SocketRaw,
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afpacket.TPacketVersion3)
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}
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type ifreq struct {
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ifrName [IFNAMSIZ]byte
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ifrHwaddr syscall.RawSockaddr
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}
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func addMulticastAddr(ifName string, addr net.HardwareAddr) error {
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fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, 0)
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if err != nil {
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return err
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}
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defer syscall.Close(fd)
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var name [IFNAMSIZ]byte
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copy(name[:], []byte(ifName))
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ifr := &ifreq{
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ifrName: name,
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ifrHwaddr: toRawSockaddr(addr),
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}
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_, _, ep := unix.Syscall(unix.SYS_IOCTL, uintptr(fd),
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unix.SIOCADDMULTI, uintptr(unsafe.Pointer(ifr)))
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if ep != 0 {
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return syscall.Errno(ep)
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}
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return nil
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}
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