492 lines
12 KiB
Go
492 lines
12 KiB
Go
package ebpf
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import (
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"errors"
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"fmt"
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"unsafe"
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"github.com/cilium/ebpf/internal"
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"github.com/cilium/ebpf/internal/btf"
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"github.com/cilium/ebpf/internal/unix"
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)
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// Generic errors returned by BPF syscalls.
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var ErrNotExist = errors.New("requested object does not exist")
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// bpfObjName is a null-terminated string made up of
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// 'A-Za-z0-9_' characters.
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type bpfObjName [unix.BPF_OBJ_NAME_LEN]byte
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// newBPFObjName truncates the result if it is too long.
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func newBPFObjName(name string) bpfObjName {
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var result bpfObjName
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copy(result[:unix.BPF_OBJ_NAME_LEN-1], name)
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return result
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}
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// invalidBPFObjNameChar returns true if char may not appear in
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// a BPF object name.
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func invalidBPFObjNameChar(char rune) bool {
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dotAllowed := objNameAllowsDot() == nil
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switch {
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case char >= 'A' && char <= 'Z':
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return false
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case char >= 'a' && char <= 'z':
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return false
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case char >= '0' && char <= '9':
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return false
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case dotAllowed && char == '.':
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return false
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case char == '_':
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return false
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default:
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return true
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}
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}
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type bpfMapCreateAttr struct {
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mapType MapType
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keySize uint32
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valueSize uint32
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maxEntries uint32
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flags uint32
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innerMapFd uint32 // since 4.12 56f668dfe00d
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numaNode uint32 // since 4.14 96eabe7a40aa
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mapName bpfObjName // since 4.15 ad5b177bd73f
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mapIfIndex uint32
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btfFd uint32
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btfKeyTypeID btf.TypeID
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btfValueTypeID btf.TypeID
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}
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type bpfMapOpAttr struct {
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mapFd uint32
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padding uint32
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key internal.Pointer
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value internal.Pointer
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flags uint64
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}
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type bpfBatchMapOpAttr struct {
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inBatch internal.Pointer
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outBatch internal.Pointer
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keys internal.Pointer
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values internal.Pointer
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count uint32
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mapFd uint32
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elemFlags uint64
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flags uint64
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}
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type bpfMapInfo struct {
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map_type uint32 // since 4.12 1e2709769086
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id uint32
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key_size uint32
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value_size uint32
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max_entries uint32
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map_flags uint32
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name bpfObjName // since 4.15 ad5b177bd73f
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ifindex uint32 // since 4.16 52775b33bb50
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btf_vmlinux_value_type_id uint32 // since 5.6 85d33df357b6
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netns_dev uint64 // since 4.16 52775b33bb50
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netns_ino uint64
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btf_id uint32 // since 4.18 78958fca7ead
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btf_key_type_id uint32 // since 4.18 9b2cf328b2ec
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btf_value_type_id uint32
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}
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type bpfProgLoadAttr struct {
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progType ProgramType
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insCount uint32
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instructions internal.Pointer
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license internal.Pointer
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logLevel uint32
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logSize uint32
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logBuf internal.Pointer
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kernelVersion uint32 // since 4.1 2541517c32be
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progFlags uint32 // since 4.11 e07b98d9bffe
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progName bpfObjName // since 4.15 067cae47771c
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progIfIndex uint32 // since 4.15 1f6f4cb7ba21
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expectedAttachType AttachType // since 4.17 5e43f899b03a
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progBTFFd uint32
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funcInfoRecSize uint32
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funcInfo internal.Pointer
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funcInfoCnt uint32
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lineInfoRecSize uint32
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lineInfo internal.Pointer
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lineInfoCnt uint32
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attachBTFID btf.TypeID
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attachProgFd uint32
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}
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type bpfProgInfo struct {
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prog_type uint32
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id uint32
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tag [unix.BPF_TAG_SIZE]byte
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jited_prog_len uint32
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xlated_prog_len uint32
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jited_prog_insns internal.Pointer
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xlated_prog_insns internal.Pointer
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load_time uint64 // since 4.15 cb4d2b3f03d8
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created_by_uid uint32
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nr_map_ids uint32
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map_ids internal.Pointer
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name bpfObjName // since 4.15 067cae47771c
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ifindex uint32
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gpl_compatible uint32
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netns_dev uint64
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netns_ino uint64
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nr_jited_ksyms uint32
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nr_jited_func_lens uint32
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jited_ksyms internal.Pointer
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jited_func_lens internal.Pointer
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btf_id uint32
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func_info_rec_size uint32
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func_info internal.Pointer
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nr_func_info uint32
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nr_line_info uint32
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line_info internal.Pointer
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jited_line_info internal.Pointer
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nr_jited_line_info uint32
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line_info_rec_size uint32
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jited_line_info_rec_size uint32
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nr_prog_tags uint32
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prog_tags internal.Pointer
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run_time_ns uint64
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run_cnt uint64
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}
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type bpfProgTestRunAttr struct {
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fd uint32
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retval uint32
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dataSizeIn uint32
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dataSizeOut uint32
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dataIn internal.Pointer
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dataOut internal.Pointer
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repeat uint32
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duration uint32
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}
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type bpfGetFDByIDAttr struct {
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id uint32
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next uint32
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}
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type bpfMapFreezeAttr struct {
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mapFd uint32
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}
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type bpfObjGetNextIDAttr struct {
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startID uint32
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nextID uint32
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openFlags uint32
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}
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func bpfProgLoad(attr *bpfProgLoadAttr) (*internal.FD, error) {
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for {
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fd, err := internal.BPF(internal.BPF_PROG_LOAD, unsafe.Pointer(attr), unsafe.Sizeof(*attr))
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// As of ~4.20 the verifier can be interrupted by a signal,
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// and returns EAGAIN in that case.
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if err == unix.EAGAIN {
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continue
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}
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if err != nil {
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return nil, err
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}
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return internal.NewFD(uint32(fd)), nil
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}
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}
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func bpfProgTestRun(attr *bpfProgTestRunAttr) error {
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_, err := internal.BPF(internal.BPF_PROG_TEST_RUN, unsafe.Pointer(attr), unsafe.Sizeof(*attr))
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return err
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}
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func bpfMapCreate(attr *bpfMapCreateAttr) (*internal.FD, error) {
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fd, err := internal.BPF(internal.BPF_MAP_CREATE, unsafe.Pointer(attr), unsafe.Sizeof(*attr))
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if err != nil {
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return nil, err
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}
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return internal.NewFD(uint32(fd)), nil
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}
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var haveNestedMaps = internal.FeatureTest("nested maps", "4.12", func() error {
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_, err := bpfMapCreate(&bpfMapCreateAttr{
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mapType: ArrayOfMaps,
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keySize: 4,
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valueSize: 4,
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maxEntries: 1,
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// Invalid file descriptor.
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innerMapFd: ^uint32(0),
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})
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if errors.Is(err, unix.EINVAL) {
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return internal.ErrNotSupported
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}
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if errors.Is(err, unix.EBADF) {
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return nil
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}
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return err
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})
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var haveMapMutabilityModifiers = internal.FeatureTest("read- and write-only maps", "5.2", func() error {
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// This checks BPF_F_RDONLY_PROG and BPF_F_WRONLY_PROG. Since
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// BPF_MAP_FREEZE appeared in 5.2 as well we don't do a separate check.
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m, err := bpfMapCreate(&bpfMapCreateAttr{
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mapType: Array,
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keySize: 4,
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valueSize: 4,
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maxEntries: 1,
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flags: unix.BPF_F_RDONLY_PROG,
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})
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if err != nil {
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return internal.ErrNotSupported
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}
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_ = m.Close()
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return nil
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})
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func bpfMapLookupElem(m *internal.FD, key, valueOut internal.Pointer) error {
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fd, err := m.Value()
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if err != nil {
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return err
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}
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attr := bpfMapOpAttr{
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mapFd: fd,
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key: key,
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value: valueOut,
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}
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_, err = internal.BPF(internal.BPF_MAP_LOOKUP_ELEM, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
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return wrapMapError(err)
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}
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func bpfMapLookupAndDelete(m *internal.FD, key, valueOut internal.Pointer) error {
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fd, err := m.Value()
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if err != nil {
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return err
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}
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attr := bpfMapOpAttr{
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mapFd: fd,
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key: key,
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value: valueOut,
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}
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_, err = internal.BPF(internal.BPF_MAP_LOOKUP_AND_DELETE_ELEM, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
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return wrapMapError(err)
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}
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func bpfMapUpdateElem(m *internal.FD, key, valueOut internal.Pointer, flags uint64) error {
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fd, err := m.Value()
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if err != nil {
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return err
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}
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attr := bpfMapOpAttr{
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mapFd: fd,
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key: key,
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value: valueOut,
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flags: flags,
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}
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_, err = internal.BPF(internal.BPF_MAP_UPDATE_ELEM, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
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return wrapMapError(err)
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}
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func bpfMapDeleteElem(m *internal.FD, key internal.Pointer) error {
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fd, err := m.Value()
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if err != nil {
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return err
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}
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attr := bpfMapOpAttr{
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mapFd: fd,
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key: key,
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}
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_, err = internal.BPF(internal.BPF_MAP_DELETE_ELEM, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
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return wrapMapError(err)
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}
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func bpfMapGetNextKey(m *internal.FD, key, nextKeyOut internal.Pointer) error {
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fd, err := m.Value()
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if err != nil {
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return err
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}
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attr := bpfMapOpAttr{
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mapFd: fd,
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key: key,
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value: nextKeyOut,
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}
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_, err = internal.BPF(internal.BPF_MAP_GET_NEXT_KEY, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
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return wrapMapError(err)
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}
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func objGetNextID(cmd internal.BPFCmd, start uint32) (uint32, error) {
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attr := bpfObjGetNextIDAttr{
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startID: start,
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}
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_, err := internal.BPF(cmd, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
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return attr.nextID, wrapObjError(err)
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}
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func bpfMapBatch(cmd internal.BPFCmd, m *internal.FD, inBatch, outBatch, keys, values internal.Pointer, count uint32, opts *BatchOptions) (uint32, error) {
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fd, err := m.Value()
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if err != nil {
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return 0, err
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}
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attr := bpfBatchMapOpAttr{
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inBatch: inBatch,
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outBatch: outBatch,
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keys: keys,
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values: values,
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count: count,
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mapFd: fd,
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}
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if opts != nil {
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attr.elemFlags = opts.ElemFlags
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attr.flags = opts.Flags
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}
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_, err = internal.BPF(cmd, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
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// always return count even on an error, as things like update might partially be fulfilled.
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return attr.count, wrapMapError(err)
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}
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func wrapObjError(err error) error {
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if err == nil {
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return nil
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}
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if errors.Is(err, unix.ENOENT) {
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return fmt.Errorf("%w", ErrNotExist)
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}
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return errors.New(err.Error())
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}
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func wrapMapError(err error) error {
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if err == nil {
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return nil
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}
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if errors.Is(err, unix.ENOENT) {
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return ErrKeyNotExist
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}
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if errors.Is(err, unix.EEXIST) {
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return ErrKeyExist
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}
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if errors.Is(err, unix.ENOTSUPP) {
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return ErrNotSupported
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}
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return errors.New(err.Error())
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}
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func bpfMapFreeze(m *internal.FD) error {
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fd, err := m.Value()
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if err != nil {
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return err
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}
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attr := bpfMapFreezeAttr{
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mapFd: fd,
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}
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_, err = internal.BPF(internal.BPF_MAP_FREEZE, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
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return err
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}
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func bpfGetProgInfoByFD(fd *internal.FD) (*bpfProgInfo, error) {
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var info bpfProgInfo
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if err := internal.BPFObjGetInfoByFD(fd, unsafe.Pointer(&info), unsafe.Sizeof(info)); err != nil {
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return nil, fmt.Errorf("can't get program info: %w", err)
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}
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return &info, nil
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}
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func bpfGetMapInfoByFD(fd *internal.FD) (*bpfMapInfo, error) {
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var info bpfMapInfo
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err := internal.BPFObjGetInfoByFD(fd, unsafe.Pointer(&info), unsafe.Sizeof(info))
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if err != nil {
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return nil, fmt.Errorf("can't get map info: %w", err)
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}
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return &info, nil
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}
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var haveObjName = internal.FeatureTest("object names", "4.15", func() error {
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attr := bpfMapCreateAttr{
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mapType: Array,
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keySize: 4,
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valueSize: 4,
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maxEntries: 1,
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mapName: newBPFObjName("feature_test"),
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}
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fd, err := bpfMapCreate(&attr)
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if err != nil {
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return internal.ErrNotSupported
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}
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_ = fd.Close()
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return nil
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})
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var objNameAllowsDot = internal.FeatureTest("dot in object names", "5.2", func() error {
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if err := haveObjName(); err != nil {
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return err
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}
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attr := bpfMapCreateAttr{
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mapType: Array,
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keySize: 4,
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valueSize: 4,
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maxEntries: 1,
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mapName: newBPFObjName(".test"),
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}
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fd, err := bpfMapCreate(&attr)
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if err != nil {
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return internal.ErrNotSupported
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}
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_ = fd.Close()
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return nil
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})
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var haveBatchAPI = internal.FeatureTest("map batch api", "5.6", func() error {
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var maxEntries uint32 = 2
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attr := bpfMapCreateAttr{
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mapType: Hash,
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keySize: 4,
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valueSize: 4,
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maxEntries: maxEntries,
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}
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fd, err := bpfMapCreate(&attr)
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if err != nil {
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return internal.ErrNotSupported
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}
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defer fd.Close()
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keys := []uint32{1, 2}
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values := []uint32{3, 4}
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kp, _ := marshalPtr(keys, 8)
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vp, _ := marshalPtr(values, 8)
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nilPtr := internal.NewPointer(nil)
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_, err = bpfMapBatch(internal.BPF_MAP_UPDATE_BATCH, fd, nilPtr, nilPtr, kp, vp, maxEntries, nil)
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if err != nil {
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return internal.ErrNotSupported
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}
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return nil
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})
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func bpfObjGetFDByID(cmd internal.BPFCmd, id uint32) (*internal.FD, error) {
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attr := bpfGetFDByIDAttr{
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id: id,
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}
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ptr, err := internal.BPF(cmd, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
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return internal.NewFD(uint32(ptr)), wrapObjError(err)
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}
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