k3s/vendor/github.com/j-keck/arping/arping_bsd.go
Darren Shepherd fa08d6076c Update vendor
2019-01-11 21:58:27 -07:00

102 lines
2.2 KiB
Go

// +build darwin freebsd openbsd
package arping
import (
"errors"
"fmt"
"net"
"os"
"runtime"
"syscall"
"time"
)
var bpf *os.File
var bpfFd int
var buflen int
var bpfArpFilter = []syscall.BpfInsn{
// make sure this is an arp packet
*syscall.BpfStmt(syscall.BPF_LD+syscall.BPF_H+syscall.BPF_ABS, 12),
*syscall.BpfJump(syscall.BPF_JMP+syscall.BPF_JEQ+syscall.BPF_K, 0x0806, 0, 1),
// if we passed all the tests, ask for the whole packet.
*syscall.BpfStmt(syscall.BPF_RET+syscall.BPF_K, -1),
// otherwise, drop it.
*syscall.BpfStmt(syscall.BPF_RET+syscall.BPF_K, 0),
}
func initialize(iface net.Interface) (err error) {
verboseLog.Println("search available /dev/bpfX")
for i := 0; i <= 10; i++ {
bpfPath := fmt.Sprintf("/dev/bpf%d", i)
bpf, err = os.OpenFile(bpfPath, os.O_RDWR, 0666)
if err != nil {
verboseLog.Printf(" open failed: %s - %s\n", bpfPath, err.Error())
} else {
verboseLog.Printf(" open success: %s\n", bpfPath)
break
}
}
bpfFd = int(bpf.Fd())
if bpfFd == -1 {
return errors.New("unable to open /dev/bpfX")
}
if err := syscall.SetBpfInterface(bpfFd, iface.Name); err != nil {
return err
}
if err := syscall.SetBpfImmediate(bpfFd, 1); err != nil {
return err
}
buflen, err = syscall.BpfBuflen(bpfFd)
if err != nil {
return err
}
if err := syscall.SetBpf(bpfFd, bpfArpFilter); err != nil {
return err
}
if err := syscall.FlushBpf(bpfFd); err != nil {
return err
}
return nil
}
func send(request arpDatagram) (time.Time, error) {
_, err := syscall.Write(bpfFd, request.MarshalWithEthernetHeader())
return time.Now(), err
}
func receive() (arpDatagram, time.Time, error) {
buffer := make([]byte, buflen)
n, err := syscall.Read(bpfFd, buffer)
if err != nil {
return arpDatagram{}, time.Now(), err
}
//
// FreeBSD uses a different bpf header (bh_tstamp differ in it's size)
// https://www.freebsd.org/cgi/man.cgi?bpf(4)#BPF_HEADER
//
var bpfHdrLength int
if runtime.GOOS == "freebsd" {
bpfHdrLength = 26
} else {
bpfHdrLength = 18
}
// skip bpf header + 14 bytes ethernet header
var hdrLength = bpfHdrLength + 14
return parseArpDatagram(buffer[hdrLength:n]), time.Now(), nil
}
func deinitialize() error {
return bpf.Close()
}