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296 lines (259 loc) · 6.47 KB
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package ebpf
import (
"bytes"
"errors"
"fmt"
"os"
"runtime"
"github.com/cilium/ebpf/asm"
"github.com/cilium/ebpf/internal"
"github.com/cilium/ebpf/internal/sys"
"github.com/cilium/ebpf/internal/tracefs"
"github.com/cilium/ebpf/internal/unix"
)
// invalidBPFObjNameChar returns true if char may not appear in
// a BPF object name.
func invalidBPFObjNameChar(char rune) bool {
dotAllowed := objNameAllowsDot() == nil
switch {
case char >= 'A' && char <= 'Z':
return false
case char >= 'a' && char <= 'z':
return false
case char >= '0' && char <= '9':
return false
case dotAllowed && char == '.':
return false
case char == '_':
return false
default:
return true
}
}
func progLoad(insns asm.Instructions, typ ProgramType, license string) (*sys.FD, error) {
buf := bytes.NewBuffer(make([]byte, 0, insns.Size()))
if err := insns.Marshal(buf, internal.NativeEndian); err != nil {
return nil, err
}
bytecode := buf.Bytes()
return sys.ProgLoad(&sys.ProgLoadAttr{
ProgType: sys.ProgType(typ),
License: sys.NewStringPointer(license),
Insns: sys.NewSlicePointer(bytecode),
InsnCnt: uint32(len(bytecode) / asm.InstructionSize),
})
}
var haveNestedMaps = internal.NewFeatureTest("nested maps", "4.12", func() error {
_, err := sys.MapCreate(&sys.MapCreateAttr{
MapType: sys.MapType(ArrayOfMaps),
KeySize: 4,
ValueSize: 4,
MaxEntries: 1,
// Invalid file descriptor.
InnerMapFd: ^uint32(0),
})
if errors.Is(err, unix.EINVAL) {
return internal.ErrNotSupported
}
if errors.Is(err, unix.EBADF) {
return nil
}
return err
})
var haveMapMutabilityModifiers = internal.NewFeatureTest("read- and write-only maps", "5.2", func() error {
// This checks BPF_F_RDONLY_PROG and BPF_F_WRONLY_PROG. Since
// BPF_MAP_FREEZE appeared in 5.2 as well we don't do a separate check.
m, err := sys.MapCreate(&sys.MapCreateAttr{
MapType: sys.MapType(Array),
KeySize: 4,
ValueSize: 4,
MaxEntries: 1,
MapFlags: unix.BPF_F_RDONLY_PROG,
})
if err != nil {
return internal.ErrNotSupported
}
_ = m.Close()
return nil
})
var haveMmapableMaps = internal.NewFeatureTest("mmapable maps", "5.5", func() error {
// This checks BPF_F_MMAPABLE, which appeared in 5.5 for array maps.
m, err := sys.MapCreate(&sys.MapCreateAttr{
MapType: sys.MapType(Array),
KeySize: 4,
ValueSize: 4,
MaxEntries: 1,
MapFlags: unix.BPF_F_MMAPABLE,
})
if err != nil {
return internal.ErrNotSupported
}
_ = m.Close()
return nil
})
var haveInnerMaps = internal.NewFeatureTest("inner maps", "5.10", func() error {
// This checks BPF_F_INNER_MAP, which appeared in 5.10.
m, err := sys.MapCreate(&sys.MapCreateAttr{
MapType: sys.MapType(Array),
KeySize: 4,
ValueSize: 4,
MaxEntries: 1,
MapFlags: unix.BPF_F_INNER_MAP,
})
if err != nil {
return internal.ErrNotSupported
}
_ = m.Close()
return nil
})
var haveNoPreallocMaps = internal.NewFeatureTest("prealloc maps", "4.6", func() error {
// This checks BPF_F_NO_PREALLOC, which appeared in 4.6.
m, err := sys.MapCreate(&sys.MapCreateAttr{
MapType: sys.MapType(Hash),
KeySize: 4,
ValueSize: 4,
MaxEntries: 1,
MapFlags: unix.BPF_F_NO_PREALLOC,
})
if err != nil {
return internal.ErrNotSupported
}
_ = m.Close()
return nil
})
func wrapMapError(err error) error {
if err == nil {
return nil
}
if errors.Is(err, unix.ENOENT) {
return sys.Error(ErrKeyNotExist, unix.ENOENT)
}
if errors.Is(err, unix.EEXIST) {
return sys.Error(ErrKeyExist, unix.EEXIST)
}
if errors.Is(err, sys.ENOTSUPP) {
return sys.Error(ErrNotSupported, sys.ENOTSUPP)
}
if errors.Is(err, unix.E2BIG) {
return fmt.Errorf("key too big for map: %w", err)
}
return err
}
var haveObjName = internal.NewFeatureTest("object names", "4.15", func() error {
attr := sys.MapCreateAttr{
MapType: sys.MapType(Array),
KeySize: 4,
ValueSize: 4,
MaxEntries: 1,
MapName: sys.NewObjName("feature_test"),
}
fd, err := sys.MapCreate(&attr)
if err != nil {
return internal.ErrNotSupported
}
_ = fd.Close()
return nil
})
var objNameAllowsDot = internal.NewFeatureTest("dot in object names", "5.2", func() error {
if err := haveObjName(); err != nil {
return err
}
attr := sys.MapCreateAttr{
MapType: sys.MapType(Array),
KeySize: 4,
ValueSize: 4,
MaxEntries: 1,
MapName: sys.NewObjName(".test"),
}
fd, err := sys.MapCreate(&attr)
if err != nil {
return internal.ErrNotSupported
}
_ = fd.Close()
return nil
})
var haveBatchAPI = internal.NewFeatureTest("map batch api", "5.6", func() error {
var maxEntries uint32 = 2
attr := sys.MapCreateAttr{
MapType: sys.MapType(Hash),
KeySize: 4,
ValueSize: 4,
MaxEntries: maxEntries,
}
fd, err := sys.MapCreate(&attr)
if err != nil {
return internal.ErrNotSupported
}
defer fd.Close()
keys := []uint32{1, 2}
values := []uint32{3, 4}
kp, _ := marshalPtr(keys, 8)
vp, _ := marshalPtr(values, 8)
err = sys.MapUpdateBatch(&sys.MapUpdateBatchAttr{
MapFd: fd.Uint(),
Keys: kp,
Values: vp,
Count: maxEntries,
})
if err != nil {
return internal.ErrNotSupported
}
return nil
})
var haveProbeReadKernel = internal.NewFeatureTest("bpf_probe_read_kernel", "5.5", func() error {
insns := asm.Instructions{
asm.Mov.Reg(asm.R1, asm.R10),
asm.Add.Imm(asm.R1, -8),
asm.Mov.Imm(asm.R2, 8),
asm.Mov.Imm(asm.R3, 0),
asm.FnProbeReadKernel.Call(),
asm.Return(),
}
fd, err := progLoad(insns, Kprobe, "GPL")
if err != nil {
return internal.ErrNotSupported
}
_ = fd.Close()
return nil
})
var haveBPFToBPFCalls = internal.NewFeatureTest("bpf2bpf calls", "4.16", func() error {
insns := asm.Instructions{
asm.Call.Label("prog2").WithSymbol("prog1"),
asm.Return(),
asm.Mov.Imm(asm.R0, 0).WithSymbol("prog2"),
asm.Return(),
}
fd, err := progLoad(insns, SocketFilter, "MIT")
if errors.Is(err, unix.EINVAL) {
return internal.ErrNotSupported
}
if err != nil {
return err
}
_ = fd.Close()
return nil
})
var haveSyscallWrapper = internal.NewFeatureTest("syscall wrapper", "4.17", func() error {
prefix := internal.PlatformPrefix()
if prefix == "" {
return fmt.Errorf("unable to find the platform prefix for (%s)", runtime.GOARCH)
}
args := tracefs.ProbeArgs{
Type: tracefs.Kprobe,
Symbol: prefix + "sys_bpf",
Pid: -1,
}
var err error
args.Group, err = tracefs.RandomGroup("ebpf_probe")
if err != nil {
return err
}
evt, err := tracefs.NewEvent(args)
if errors.Is(err, os.ErrNotExist) {
return internal.ErrNotSupported
}
if err != nil {
return err
}
return evt.Close()
})