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ringbuf: Windows support
Signed-off-by: Lorenz Bauer <[email protected]>
1 parent c9de606 commit ae22611

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11 files changed

+578
-189
lines changed

11 files changed

+578
-189
lines changed

‎internal/efw/map.go‎

Lines changed: 109 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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//go:build windows
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package efw
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import (
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"runtime"
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"syscall"
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"unsafe"
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"golang.org/x/sys/windows"
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)
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/*
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ebpf_ring_buffer_map_map_buffer(
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fd_t map_fd,
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_Outptr_result_maybenull_ void** consumer,
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_Outptr_result_maybenull_ const void** producer,
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_Outptr_result_buffer_maybenull_(*data_size) const uint8_t** data,
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_Out_ size_t* data_size) EBPF_NO_EXCEPT;
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*/
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var ebpfRingBufferMapMapBufferProc = newProc("ebpf_ring_buffer_map_map_buffer")
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func EbpfRingBufferMapMapBuffer(mapFd int) (consumer, producer, data *uint8, dataLen Size, _ error) {
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addr, err := ebpfRingBufferMapMapBufferProc.Find()
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if err != nil {
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return nil, nil, nil, 0, err
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}
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err = errorResult(syscall.SyscallN(addr,
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uintptr(mapFd),
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uintptr(unsafe.Pointer(&consumer)),
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uintptr(unsafe.Pointer(&producer)),
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uintptr(unsafe.Pointer(&data)),
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uintptr(unsafe.Pointer(&dataLen)),
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))
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if err != nil {
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return nil, nil, nil, 0, err
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}
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return consumer, producer, data, dataLen, nil
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}
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/*
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ebpf_ring_buffer_map_unmap_buffer(
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fd_t map_fd, _In_ void* consumer, _In_ const void* producer, _In_ const void* data) EBPF_NO_EXCEPT;
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*/
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var ebpfRingBufferMapUnmapBufferProc = newProc("ebpf_ring_buffer_map_unmap_buffer")
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func EbpfRingBufferMapUnmapBuffer(mapFd int, consumer, producer, data *uint8) error {
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addr, err := ebpfRingBufferMapUnmapBufferProc.Find()
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if err != nil {
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return err
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}
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return errorResult(syscall.SyscallN(addr,
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uintptr(mapFd),
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uintptr(unsafe.Pointer(consumer)),
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uintptr(unsafe.Pointer(producer)),
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uintptr(unsafe.Pointer(data)),
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))
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}
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/*
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ebpf_result_t ebpf_map_set_wait_handle(
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fd_t map_fd,
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uint64_t index,
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ebpf_handle_t handle)
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*/
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var ebpfMapSetWaitHandleProc = newProc("ebpf_map_set_wait_handle")
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func EbpfMapSetWaitHandle(mapFd int, index uint64, handle windows.Handle) error {
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addr, err := ebpfMapSetWaitHandleProc.Find()
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if err != nil {
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return err
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}
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return errorResult(syscall.SyscallN(addr,
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uintptr(mapFd),
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uintptr(index),
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uintptr(handle),
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))
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}
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/*
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ebpf_result_t ebpf_ring_buffer_map_write(
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fd_t ring_buffer_map_fd,
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const void* data,
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size_t data_length)
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*/
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var ebpfRingBufferMapWriteProc = newProc("ebpf_ring_buffer_map_write")
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func EbpfRingBufferMapWrite(ringBufferMapFd int, data []byte) error {
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addr, err := ebpfRingBufferMapWriteProc.Find()
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if err != nil {
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return err
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}
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err = errorResult(syscall.SyscallN(addr,
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uintptr(ringBufferMapFd),
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uintptr(unsafe.Pointer(&data[0])),
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uintptr(len(data)),
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))
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runtime.KeepAlive(data)
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return err
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}

‎ringbuf/doc.go‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
// Package ringbuf allows interacting with Linux BPF ring buffer.
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// Package ringbuf allows interacting with the BPF ring buffer.
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//
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// BPF allows submitting custom events to a BPF ring buffer map set up
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// by userspace. This is very useful to push things like packet samples

‎ringbuf/helper_other_test.go‎

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//go:build !windows
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package ringbuf
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import (
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"testing"
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"github.com/go-quicktest/qt"
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"github.com/cilium/ebpf"
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"github.com/cilium/ebpf/asm"
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)
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func mustOutputSamplesProg(tb testing.TB, sampleMessages ...sampleMessage) (*ebpf.Program, *ebpf.Map) {
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tb.Helper()
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events, err := ebpf.NewMap(&ebpf.MapSpec{
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Type: ebpf.RingBuf,
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MaxEntries: 4096,
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})
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qt.Assert(tb, qt.IsNil(err))
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tb.Cleanup(func() {
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events.Close()
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})
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var maxSampleSize int
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for _, sampleMessage := range sampleMessages {
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if sampleMessage.size > maxSampleSize {
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maxSampleSize = sampleMessage.size
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}
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}
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insns := asm.Instructions{
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asm.LoadImm(asm.R0, 0x0102030404030201, asm.DWord),
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asm.Mov.Reg(asm.R9, asm.R1),
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}
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bufDwords := (maxSampleSize / 8) + 1
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for i := range bufDwords {
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insns = append(insns,
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asm.StoreMem(asm.RFP, int16(i+1)*-8, asm.R0, asm.DWord),
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)
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}
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for _, sampleMessage := range sampleMessages {
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insns = append(insns,
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asm.LoadMapPtr(asm.R1, events.FD()),
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asm.Mov.Imm(asm.R2, int32(sampleMessage.size)),
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asm.Mov.Imm(asm.R3, int32(0)),
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asm.FnRingbufReserve.Call(),
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asm.JEq.Imm(asm.R0, 0, "exit"),
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asm.Mov.Reg(asm.R5, asm.R0),
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)
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for i := range sampleMessage.size {
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insns = append(insns,
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asm.LoadMem(asm.R4, asm.RFP, int16(i+1)*-1, asm.Byte),
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asm.StoreMem(asm.R5, int16(i), asm.R4, asm.Byte),
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)
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}
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if sampleMessage.discard {
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insns = append(insns,
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asm.Mov.Reg(asm.R1, asm.R5),
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asm.Mov.Imm(asm.R2, sampleMessage.flags),
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asm.FnRingbufDiscard.Call(),
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)
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} else {
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insns = append(insns,
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asm.Mov.Reg(asm.R1, asm.R5),
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asm.Mov.Imm(asm.R2, sampleMessage.flags),
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asm.FnRingbufSubmit.Call(),
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)
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}
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}
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insns = append(insns,
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asm.Mov.Imm(asm.R0, int32(0)).WithSymbol("exit"),
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asm.Return(),
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)
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prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
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License: "MIT",
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Type: ebpf.XDP,
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Instructions: insns,
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})
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qt.Assert(tb, qt.IsNil(err))
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tb.Cleanup(func() {
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prog.Close()
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})
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return prog, events
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}

‎ringbuf/helper_windows_test.go‎

Lines changed: 75 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,75 @@
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package ringbuf
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import (
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"testing"
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"github.com/go-quicktest/qt"
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"github.com/cilium/ebpf"
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"github.com/cilium/ebpf/asm"
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)
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func mustOutputSamplesProg(tb testing.TB, sampleMessages ...sampleMessage) (*ebpf.Program, *ebpf.Map) {
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tb.Helper()
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events, err := ebpf.NewMap(&ebpf.MapSpec{
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Type: ebpf.WindowsRingBuf,
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MaxEntries: 4096,
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})
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qt.Assert(tb, qt.IsNil(err))
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tb.Cleanup(func() {
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events.Close()
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})
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var maxSampleSize int
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for _, sampleMessage := range sampleMessages {
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if sampleMessage.size > maxSampleSize {
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maxSampleSize = sampleMessage.size
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}
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}
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insns := asm.Instructions{
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asm.LoadImm(asm.R0, 0x0102030404030201, asm.DWord),
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asm.Mov.Reg(asm.R9, asm.R1),
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}
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bufDwords := (maxSampleSize / 8) + 1
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for i := range bufDwords {
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insns = append(insns,
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asm.StoreMem(asm.RFP, int16(i+1)*-8, asm.R0, asm.DWord),
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)
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}
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for _, sampleMessage := range sampleMessages {
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if sampleMessage.discard {
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tb.Skip("discard is not supported on Windows")
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}
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insns = append(insns,
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asm.LoadMapPtr(asm.R1, events.FD()),
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asm.Mov.Reg(asm.R2, asm.RFP),
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asm.Add.Imm(asm.R2, -int32(8*bufDwords)),
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asm.Mov.Imm(asm.R3, int32(sampleMessage.size)),
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asm.Mov.Imm(asm.R4, sampleMessage.flags),
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asm.WindowsFnRingbufOutput.Call(),
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asm.JNE.Imm(asm.R0, 0, "exit"),
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)
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}
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insns = append(insns,
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asm.Mov.Imm(asm.R0, int32(0)),
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asm.Return().WithSymbol("exit"),
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)
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prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
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License: "MIT",
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Type: ebpf.WindowsXDPTest,
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Instructions: insns,
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})
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qt.Assert(tb, qt.IsNil(err))
70+
tb.Cleanup(func() {
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prog.Close()
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})
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return prog, events
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}

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