func (d *afpacket) Write(from ethernet.Frame) (err error) {
copy(d.sockaddrLL.Addr[:6], []byte(from.Destination()))
err = unix.Sendto(d.fd, []byte(from), 0, d.sockaddrLL)
if err != nil {
return
}
return
}
func TestWriteFrame(t *testing.T) {
var (
ifce *net.Interface
err error
d Dev
)
if ifce, err = net.InterfaceByName(*dev); err != nil {
t.Fatalf("getting interface error: %v", err)
}
d, err = NewDev(ifce, nil)
if err != nil {
t.Fatal(err)
}
dst, err := net.ParseMAC("ff:ff:ff:ff:ff:ff")
if err != nil {
t.Fatal(err)
}
src, err := net.ParseMAC("12:34:56:78:9a:bc")
if err != nil {
t.Fatal(err)
}
var frame ethernet.Frame
w := func() (err error) {
(&frame).Prepare(dst, src, ethernet.NotTagged, ethernet.WSMP, 13)
copy(frame.Payload(), "Hello, World!")
err = d.Write(frame)
if err != nil {
return
}
return
}
for i := 0; i < 16; i++ {
if nil != w() {
t.Fatal(err)
}
}
(&frame).Resize(d.Interface().MTU)
if err = d.Write(frame); err != nil {
t.Fatalf("writing frame with payload size equal to MTU fails: %v", err)
}
(&frame).Resize(d.Interface().MTU + 1)
if nil == d.Write(frame) {
t.Fatalf("writing frame with payload larger than MTU does not fail")
}
err = d.Close()
if err != nil {
t.Fatal(err)
}
if err = w(); nil == err {
t.Fatal("closed Dev can still write")
}
}
func (d *afpacket) Read(to *ethernet.Frame) (err error) {
to.Resize(d.ifce.MTU)
for {
*to = (*to)[:cap(*to)]
var n int
n, _, err = unix.Recvfrom(d.fd, []byte(*to), 0)
if err != nil {
return
}
*to = (*to)[:n]
if !equalMAC(to.Source(), d.ifce.HardwareAddr) && (d.filter == nil || d.filter(*to)) {
return
}
}
}
func (d *bpfDev) Read(to *ethernet.Frame) (err error) {
to.Resize(d.ifce.MTU)
for {
for d.p < d.n {
hdr := (*bpfHdr)(unsafe.Pointer(&d.readBuf[d.p]))
frameStart := d.p + int(hdr.hdrlen)
n := int(hdr.caplen)
*to = (*to)[:n]
copy(*to, d.readBuf[frameStart:frameStart+n])
d.p += bpfWordalign(int(hdr.hdrlen) + int(hdr.caplen))
if !equalMAC(to.Source(), d.ifce.HardwareAddr) && (d.filter == nil || d.filter(*to)) {
return
}
}
d.n, err = d.fd.Read(d.readBuf)
if err != nil {
return
}
d.p = 0
}
}
func TestReadFrame(t *testing.T) {
var (
ifce *net.Interface
err error
d Dev
)
if ifce, err = net.InterfaceByName(*dev); err != nil {
t.Fatalf("getting interface error: %v", err)
}
d, err = NewDev(ifce, nil)
if err != nil {
t.Fatal(err)
}
var to ethernet.Frame
for i := 0; i < 16; i++ {
err = d.Read(&to)
t.Logf("got frame: from %v to %v (ethertype %v): % x\n", to.Source(), to.Destination(), to.Ethertype(), to.Payload())
if err != nil {
t.Fatal(err)
}
}
err = d.Close()
if err != nil {
t.Fatal(err)
}
for i := 0; i < 1024; i++ {
err = d.Read(&to)
if err != nil {
break
}
}
if err == nil {
t.Fatal("closed Dev can still read")
}
}