package ebpf import ( "errors" "fmt" "io" "path/filepath" "reflect" "strings" "github.com/cilium/ebpf/internal" "github.com/cilium/ebpf/internal/btf" "github.com/cilium/ebpf/internal/unix" ) // Errors returned by Map and MapIterator methods. var ( ErrKeyNotExist = errors.New("key does not exist") ErrKeyExist = errors.New("key already exists") ErrIterationAborted = errors.New("iteration aborted") ) // MapOptions control loading a map into the kernel. type MapOptions struct { // The base path to pin maps in if requested via PinByName. // Existing maps will be re-used if they are compatible, otherwise an // error is returned. PinPath string LoadPinOptions LoadPinOptions } // MapID represents the unique ID of an eBPF map type MapID uint32 // MapSpec defines a Map. type MapSpec struct { // Name is passed to the kernel as a debug aid. Must only contain // alpha numeric and '_' characters. Name string Type MapType KeySize uint32 ValueSize uint32 MaxEntries uint32 // Flags is passed to the kernel and specifies additional map // creation attributes. Flags uint32 // Automatically pin and load a map from MapOptions.PinPath. // Generates an error if an existing pinned map is incompatible with the MapSpec. Pinning PinType // Specify numa node during map creation // (effective only if unix.BPF_F_NUMA_NODE flag is set, // which can be imported from golang.org/x/sys/unix) NumaNode uint32 // The initial contents of the map. May be nil. Contents []MapKV // Whether to freeze a map after setting its initial contents. Freeze bool // InnerMap is used as a template for ArrayOfMaps and HashOfMaps InnerMap *MapSpec // The BTF associated with this map. BTF *btf.Map } func (ms *MapSpec) String() string { return fmt.Sprintf("%s(keySize=%d, valueSize=%d, maxEntries=%d, flags=%d)", ms.Type, ms.KeySize, ms.ValueSize, ms.MaxEntries, ms.Flags) } // Copy returns a copy of the spec. // // MapSpec.Contents is a shallow copy. func (ms *MapSpec) Copy() *MapSpec { if ms == nil { return nil } cpy := *ms cpy.Contents = make([]MapKV, len(ms.Contents)) copy(cpy.Contents, ms.Contents) cpy.InnerMap = ms.InnerMap.Copy() return &cpy } // MapKV is used to initialize the contents of a Map. type MapKV struct { Key interface{} Value interface{} } func (ms *MapSpec) checkCompatibility(m *Map) error { switch { case m.typ != ms.Type: return fmt.Errorf("expected type %v, got %v", ms.Type, m.typ) case m.keySize != ms.KeySize: return fmt.Errorf("expected key size %v, got %v", ms.KeySize, m.keySize) case m.valueSize != ms.ValueSize: return fmt.Errorf("expected value size %v, got %v", ms.ValueSize, m.valueSize) case m.maxEntries != ms.MaxEntries: return fmt.Errorf("expected max entries %v, got %v", ms.MaxEntries, m.maxEntries) case m.flags != ms.Flags: return fmt.Errorf("expected flags %v, got %v", ms.Flags, m.flags) } return nil } // Map represents a Map file descriptor. // // It is not safe to close a map which is used by other goroutines. // // Methods which take interface{} arguments by default encode // them using binary.Read/Write in the machine's native endianness. // // Implement encoding.BinaryMarshaler or encoding.BinaryUnmarshaler // if you require custom encoding. type Map struct { name string fd *internal.FD typ MapType keySize uint32 valueSize uint32 maxEntries uint32 flags uint32 pinnedPath string // Per CPU maps return values larger than the size in the spec fullValueSize int } // NewMapFromFD creates a map from a raw fd. // // You should not use fd after calling this function. func NewMapFromFD(fd int) (*Map, error) { if fd < 0 { return nil, errors.New("invalid fd") } return newMapFromFD(internal.NewFD(uint32(fd))) } func newMapFromFD(fd *internal.FD) (*Map, error) { info, err := newMapInfoFromFd(fd) if err != nil { fd.Close() return nil, fmt.Errorf("get map info: %s", err) } return newMap(fd, info.Name, info.Type, info.KeySize, info.ValueSize, info.MaxEntries, info.Flags) } // NewMap creates a new Map. // // It's equivalent to calling NewMapWithOptions with default options. func NewMap(spec *MapSpec) (*Map, error) { return NewMapWithOptions(spec, MapOptions{}) } // NewMapWithOptions creates a new Map. // // Creating a map for the first time will perform feature detection // by creating small, temporary maps. // // The caller is responsible for ensuring the process' rlimit is set // sufficiently high for locking memory during map creation. This can be done // by calling unix.Setrlimit with unix.RLIMIT_MEMLOCK prior to calling NewMapWithOptions. func NewMapWithOptions(spec *MapSpec, opts MapOptions) (*Map, error) { btfs := make(btfHandleCache) defer btfs.close() return newMapWithOptions(spec, opts, btfs) } func newMapWithOptions(spec *MapSpec, opts MapOptions, btfs btfHandleCache) (_ *Map, err error) { closeOnError := func(c io.Closer) { if err != nil { c.Close() } } switch spec.Pinning { case PinByName: if spec.Name == "" || opts.PinPath == "" { return nil, fmt.Errorf("pin by name: missing Name or PinPath") } path := filepath.Join(opts.PinPath, spec.Name) m, err := LoadPinnedMap(path, &opts.LoadPinOptions) if errors.Is(err, unix.ENOENT) { break } if err != nil { return nil, fmt.Errorf("load pinned map: %w", err) } defer closeOnError(m) if err := spec.checkCompatibility(m); err != nil { return nil, fmt.Errorf("use pinned map %s: %s", spec.Name, err) } return m, nil case PinNone: // Nothing to do here default: return nil, fmt.Errorf("unsupported pin type %d", int(spec.Pinning)) } var innerFd *internal.FD if spec.Type == ArrayOfMaps || spec.Type == HashOfMaps { if spec.InnerMap == nil { return nil, fmt.Errorf("%s requires InnerMap", spec.Type) } if spec.InnerMap.Pinning != PinNone { return nil, errors.New("inner maps cannot be pinned") } template, err := createMap(spec.InnerMap, nil, opts, btfs) if err != nil { return nil, err } defer template.Close() innerFd = template.fd } m, err := createMap(spec, innerFd, opts, btfs) if err != nil { return nil, err } defer closeOnError(m) if spec.Pinning == PinByName { path := filepath.Join(opts.PinPath, spec.Name) if err := m.Pin(path); err != nil { return nil, fmt.Errorf("pin map: %s", err) } } return m, nil } func createMap(spec *MapSpec, inner *internal.FD, opts MapOptions, btfs btfHandleCache) (_ *Map, err error) { closeOnError := func(closer io.Closer) { if err != nil { closer.Close() } } spec = spec.Copy() switch spec.Type { case ArrayOfMaps: fallthrough case HashOfMaps: if err := haveNestedMaps(); err != nil { return nil, err } if spec.ValueSize != 0 && spec.ValueSize != 4 { return nil, errors.New("ValueSize must be zero or four for map of map") } spec.ValueSize = 4 case PerfEventArray: if spec.KeySize != 0 && spec.KeySize != 4 { return nil, errors.New("KeySize must be zero or four for perf event array") } spec.KeySize = 4 if spec.ValueSize != 0 && spec.ValueSize != 4 { return nil, errors.New("ValueSize must be zero or four for perf event array") } spec.ValueSize = 4 if spec.MaxEntries == 0 { n, err := internal.PossibleCPUs() if err != nil { return nil, fmt.Errorf("perf event array: %w", err) } spec.MaxEntries = uint32(n) } } if spec.Flags&(unix.BPF_F_RDONLY_PROG|unix.BPF_F_WRONLY_PROG) > 0 || spec.Freeze { if err := haveMapMutabilityModifiers(); err != nil { return nil, fmt.Errorf("map create: %w", err) } } attr := bpfMapCreateAttr{ mapType: spec.Type, keySize: spec.KeySize, valueSize: spec.ValueSize, maxEntries: spec.MaxEntries, flags: spec.Flags, numaNode: spec.NumaNode, } if inner != nil { var err error attr.innerMapFd, err = inner.Value() if err != nil { return nil, fmt.Errorf("map create: %w", err) } } if haveObjName() == nil { attr.mapName = newBPFObjName(spec.Name) } var btfDisabled bool if spec.BTF != nil { handle, err := btfs.load(btf.MapSpec(spec.BTF)) btfDisabled = errors.Is(err, btf.ErrNotSupported) if err != nil && !btfDisabled { return nil, fmt.Errorf("load BTF: %w", err) } if handle != nil { attr.btfFd = uint32(handle.FD()) attr.btfKeyTypeID = btf.MapKey(spec.BTF).ID() attr.btfValueTypeID = btf.MapValue(spec.BTF).ID() } } fd, err := bpfMapCreate(&attr) if err != nil { if errors.Is(err, unix.EPERM) { return nil, fmt.Errorf("map create: RLIMIT_MEMLOCK may be too low: %w", err) } if btfDisabled { return nil, fmt.Errorf("map create without BTF: %w", err) } return nil, fmt.Errorf("map create: %w", err) } defer closeOnError(fd) m, err := newMap(fd, spec.Name, spec.Type, spec.KeySize, spec.ValueSize, spec.MaxEntries, spec.Flags) if err != nil { return nil, fmt.Errorf("map create: %w", err) } if err := m.populate(spec.Contents); err != nil { return nil, fmt.Errorf("map create: can't set initial contents: %w", err) } if spec.Freeze { if err := m.Freeze(); err != nil { return nil, fmt.Errorf("can't freeze map: %w", err) } } return m, nil } func newMap(fd *internal.FD, name string, typ MapType, keySize, valueSize, maxEntries, flags uint32) (*Map, error) { m := &Map{ name, fd, typ, keySize, valueSize, maxEntries, flags, "", int(valueSize), } if !typ.hasPerCPUValue() { return m, nil } possibleCPUs, err := internal.PossibleCPUs() if err != nil { return nil, err } m.fullValueSize = align(int(valueSize), 8) * possibleCPUs return m, nil } func (m *Map) String() string { if m.name != "" { return fmt.Sprintf("%s(%s)#%v", m.typ, m.name, m.fd) } return fmt.Sprintf("%s#%v", m.typ, m.fd) } // Type returns the underlying type of the map. func (m *Map) Type() MapType { return m.typ } // KeySize returns the size of the map key in bytes. func (m *Map) KeySize() uint32 { return m.keySize } // ValueSize returns the size of the map value in bytes. func (m *Map) ValueSize() uint32 { return m.valueSize } // MaxEntries returns the maximum number of elements the map can hold. func (m *Map) MaxEntries() uint32 { return m.maxEntries } // Flags returns the flags of the map. func (m *Map) Flags() uint32 { return m.flags } // Info returns metadata about the map. func (m *Map) Info() (*MapInfo, error) { return newMapInfoFromFd(m.fd) } // Lookup retrieves a value from a Map. // // Calls Close() on valueOut if it is of type **Map or **Program, // and *valueOut is not nil. // // Returns an error if the key doesn't exist, see ErrKeyNotExist. func (m *Map) Lookup(key, valueOut interface{}) error { valuePtr, valueBytes := makeBuffer(valueOut, m.fullValueSize) if err := m.lookup(key, valuePtr); err != nil { return err } return m.unmarshalValue(valueOut, valueBytes) } // LookupAndDelete retrieves and deletes a value from a Map. // // Returns ErrKeyNotExist if the key doesn't exist. func (m *Map) LookupAndDelete(key, valueOut interface{}) error { valuePtr, valueBytes := makeBuffer(valueOut, m.fullValueSize) keyPtr, err := m.marshalKey(key) if err != nil { return fmt.Errorf("can't marshal key: %w", err) } if err := bpfMapLookupAndDelete(m.fd, keyPtr, valuePtr); err != nil { return fmt.Errorf("lookup and delete failed: %w", err) } return m.unmarshalValue(valueOut, valueBytes) } // LookupBytes gets a value from Map. // // Returns a nil value if a key doesn't exist. func (m *Map) LookupBytes(key interface{}) ([]byte, error) { valueBytes := make([]byte, m.fullValueSize) valuePtr := internal.NewSlicePointer(valueBytes) err := m.lookup(key, valuePtr) if errors.Is(err, ErrKeyNotExist) { return nil, nil } return valueBytes, err } func (m *Map) lookup(key interface{}, valueOut internal.Pointer) error { keyPtr, err := m.marshalKey(key) if err != nil { return fmt.Errorf("can't marshal key: %w", err) } if err = bpfMapLookupElem(m.fd, keyPtr, valueOut); err != nil { return fmt.Errorf("lookup failed: %w", err) } return nil } // MapUpdateFlags controls the behaviour of the Map.Update call. // // The exact semantics depend on the specific MapType. type MapUpdateFlags uint64 const ( // UpdateAny creates a new element or update an existing one. UpdateAny MapUpdateFlags = iota // UpdateNoExist creates a new element. UpdateNoExist MapUpdateFlags = 1 << (iota - 1) // UpdateExist updates an existing element. UpdateExist ) // Put replaces or creates a value in map. // // It is equivalent to calling Update with UpdateAny. func (m *Map) Put(key, value interface{}) error { return m.Update(key, value, UpdateAny) } // Update changes the value of a key. func (m *Map) Update(key, value interface{}, flags MapUpdateFlags) error { keyPtr, err := m.marshalKey(key) if err != nil { return fmt.Errorf("can't marshal key: %w", err) } valuePtr, err := m.marshalValue(value) if err != nil { return fmt.Errorf("can't marshal value: %w", err) } if err = bpfMapUpdateElem(m.fd, keyPtr, valuePtr, uint64(flags)); err != nil { return fmt.Errorf("update failed: %w", err) } return nil } // Delete removes a value. // // Returns ErrKeyNotExist if the key does not exist. func (m *Map) Delete(key interface{}) error { keyPtr, err := m.marshalKey(key) if err != nil { return fmt.Errorf("can't marshal key: %w", err) } if err = bpfMapDeleteElem(m.fd, keyPtr); err != nil { return fmt.Errorf("delete failed: %w", err) } return nil } // NextKey finds the key following an initial key. // // See NextKeyBytes for details. // // Returns ErrKeyNotExist if there is no next key. func (m *Map) NextKey(key, nextKeyOut interface{}) error { nextKeyPtr, nextKeyBytes := makeBuffer(nextKeyOut, int(m.keySize)) if err := m.nextKey(key, nextKeyPtr); err != nil { return err } if err := m.unmarshalKey(nextKeyOut, nextKeyBytes); err != nil { return fmt.Errorf("can't unmarshal next key: %w", err) } return nil } // NextKeyBytes returns the key following an initial key as a byte slice. // // Passing nil will return the first key. // // Use Iterate if you want to traverse all entries in the map. // // Returns nil if there are no more keys. func (m *Map) NextKeyBytes(key interface{}) ([]byte, error) { nextKey := make([]byte, m.keySize) nextKeyPtr := internal.NewSlicePointer(nextKey) err := m.nextKey(key, nextKeyPtr) if errors.Is(err, ErrKeyNotExist) { return nil, nil } return nextKey, err } func (m *Map) nextKey(key interface{}, nextKeyOut internal.Pointer) error { var ( keyPtr internal.Pointer err error ) if key != nil { keyPtr, err = m.marshalKey(key) if err != nil { return fmt.Errorf("can't marshal key: %w", err) } } if err = bpfMapGetNextKey(m.fd, keyPtr, nextKeyOut); err != nil { return fmt.Errorf("next key failed: %w", err) } return nil } // BatchLookup looks up many elements in a map at once. // // "keysOut" and "valuesOut" must be of type slice, a pointer // to a slice or buffer will not work. // "prevKey" is the key to start the batch lookup from, it will // *not* be included in the results. Use nil to start at the first key. // // ErrKeyNotExist is returned when the batch lookup has reached // the end of all possible results, even when partial results // are returned. It should be used to evaluate when lookup is "done". func (m *Map) BatchLookup(prevKey, nextKeyOut, keysOut, valuesOut interface{}, opts *BatchOptions) (int, error) { return m.batchLookup(internal.BPF_MAP_LOOKUP_BATCH, prevKey, nextKeyOut, keysOut, valuesOut, opts) } // BatchLookupAndDelete looks up many elements in a map at once, // // It then deletes all those elements. // "keysOut" and "valuesOut" must be of type slice, a pointer // to a slice or buffer will not work. // "prevKey" is the key to start the batch lookup from, it will // *not* be included in the results. Use nil to start at the first key. // // ErrKeyNotExist is returned when the batch lookup has reached // the end of all possible results, even when partial results // are returned. It should be used to evaluate when lookup is "done". func (m *Map) BatchLookupAndDelete(prevKey, nextKeyOut, keysOut, valuesOut interface{}, opts *BatchOptions) (int, error) { return m.batchLookup(internal.BPF_MAP_LOOKUP_AND_DELETE_BATCH, prevKey, nextKeyOut, keysOut, valuesOut, opts) } func (m *Map) batchLookup(cmd internal.BPFCmd, startKey, nextKeyOut, keysOut, valuesOut interface{}, opts *BatchOptions) (int, error) { if err := haveBatchAPI(); err != nil { return 0, err } if m.typ.hasPerCPUValue() { return 0, ErrNotSupported } keysValue := reflect.ValueOf(keysOut) if keysValue.Kind() != reflect.Slice { return 0, fmt.Errorf("keys must be a slice") } valuesValue := reflect.ValueOf(valuesOut) if valuesValue.Kind() != reflect.Slice { return 0, fmt.Errorf("valuesOut must be a slice") } count := keysValue.Len() if count != valuesValue.Len() { return 0, fmt.Errorf("keysOut and valuesOut must be the same length") } keyBuf := make([]byte, count*int(m.keySize)) keyPtr := internal.NewSlicePointer(keyBuf) valueBuf := make([]byte, count*int(m.fullValueSize)) valuePtr := internal.NewSlicePointer(valueBuf) var ( startPtr internal.Pointer err error retErr error ) if startKey != nil { startPtr, err = marshalPtr(startKey, int(m.keySize)) if err != nil { return 0, err } } nextPtr, nextBuf := makeBuffer(nextKeyOut, int(m.keySize)) ct, err := bpfMapBatch(cmd, m.fd, startPtr, nextPtr, keyPtr, valuePtr, uint32(count), opts) if err != nil { if !errors.Is(err, ErrKeyNotExist) { return 0, err } retErr = ErrKeyNotExist } err = m.unmarshalKey(nextKeyOut, nextBuf) if err != nil { return 0, err } err = unmarshalBytes(keysOut, keyBuf) if err != nil { return 0, err } err = unmarshalBytes(valuesOut, valueBuf) if err != nil { retErr = err } return int(ct), retErr } // BatchUpdate updates the map with multiple keys and values // simultaneously. // "keys" and "values" must be of type slice, a pointer // to a slice or buffer will not work. func (m *Map) BatchUpdate(keys, values interface{}, opts *BatchOptions) (int, error) { if err := haveBatchAPI(); err != nil { return 0, err } if m.typ.hasPerCPUValue() { return 0, ErrNotSupported } keysValue := reflect.ValueOf(keys) if keysValue.Kind() != reflect.Slice { return 0, fmt.Errorf("keys must be a slice") } valuesValue := reflect.ValueOf(values) if valuesValue.Kind() != reflect.Slice { return 0, fmt.Errorf("values must be a slice") } var ( count = keysValue.Len() valuePtr internal.Pointer err error ) if count != valuesValue.Len() { return 0, fmt.Errorf("keys and values must be the same length") } keyPtr, err := marshalPtr(keys, count*int(m.keySize)) if err != nil { return 0, err } valuePtr, err = marshalPtr(values, count*int(m.valueSize)) if err != nil { return 0, err } var nilPtr internal.Pointer ct, err := bpfMapBatch(internal.BPF_MAP_UPDATE_BATCH, m.fd, nilPtr, nilPtr, keyPtr, valuePtr, uint32(count), opts) return int(ct), err } // BatchDelete batch deletes entries in the map by keys. // "keys" must be of type slice, a pointer to a slice or buffer will not work. func (m *Map) BatchDelete(keys interface{}, opts *BatchOptions) (int, error) { if err := haveBatchAPI(); err != nil { return 0, err } if m.typ.hasPerCPUValue() { return 0, ErrNotSupported } keysValue := reflect.ValueOf(keys) if keysValue.Kind() != reflect.Slice { return 0, fmt.Errorf("keys must be a slice") } count := keysValue.Len() keyPtr, err := marshalPtr(keys, count*int(m.keySize)) if err != nil { return 0, fmt.Errorf("cannot marshal keys: %v", err) } var nilPtr internal.Pointer ct, err := bpfMapBatch(internal.BPF_MAP_DELETE_BATCH, m.fd, nilPtr, nilPtr, keyPtr, nilPtr, uint32(count), opts) return int(ct), err } // Iterate traverses a map. // // It's safe to create multiple iterators at the same time. // // It's not possible to guarantee that all keys in a map will be // returned if there are concurrent modifications to the map. func (m *Map) Iterate() *MapIterator { return newMapIterator(m) } // Close removes a Map func (m *Map) Close() error { if m == nil { // This makes it easier to clean up when iterating maps // of maps / programs. return nil } return m.fd.Close() } // FD gets the file descriptor of the Map. // // Calling this function is invalid after Close has been called. func (m *Map) FD() int { fd, err := m.fd.Value() if err != nil { // Best effort: -1 is the number most likely to be an // invalid file descriptor. return -1 } return int(fd) } // Clone creates a duplicate of the Map. // // Closing the duplicate does not affect the original, and vice versa. // Changes made to the map are reflected by both instances however. // If the original map was pinned, the cloned map will not be pinned by default. // // Cloning a nil Map returns nil. func (m *Map) Clone() (*Map, error) { if m == nil { return nil, nil } dup, err := m.fd.Dup() if err != nil { return nil, fmt.Errorf("can't clone map: %w", err) } return &Map{ m.name, dup, m.typ, m.keySize, m.valueSize, m.maxEntries, m.flags, "", m.fullValueSize, }, nil } // Pin persists the map on the BPF virtual file system past the lifetime of // the process that created it . // // Calling Pin on a previously pinned map will overwrite the path, except when // the new path already exists. Re-pinning across filesystems is not supported. // You can Clone a map to pin it to a different path. // // This requires bpffs to be mounted above fileName. See https://docs.cilium.io/en/k8s-doc/admin/#admin-mount-bpffs func (m *Map) Pin(fileName string) error { if err := internal.Pin(m.pinnedPath, fileName, m.fd); err != nil { return err } m.pinnedPath = fileName return nil } // Unpin removes the persisted state for the map from the BPF virtual filesystem. // // Failed calls to Unpin will not alter the state returned by IsPinned. // // Unpinning an unpinned Map returns nil. func (m *Map) Unpin() error { if err := internal.Unpin(m.pinnedPath); err != nil { return err } m.pinnedPath = "" return nil } // IsPinned returns true if the map has a non-empty pinned path. func (m *Map) IsPinned() bool { return m.pinnedPath != "" } // Freeze prevents a map to be modified from user space. // // It makes no changes to kernel-side restrictions. func (m *Map) Freeze() error { if err := haveMapMutabilityModifiers(); err != nil { return fmt.Errorf("can't freeze map: %w", err) } if err := bpfMapFreeze(m.fd); err != nil { return fmt.Errorf("can't freeze map: %w", err) } return nil } func (m *Map) populate(contents []MapKV) error { for _, kv := range contents { if err := m.Put(kv.Key, kv.Value); err != nil { return fmt.Errorf("key %v: %w", kv.Key, err) } } return nil } func (m *Map) marshalKey(data interface{}) (internal.Pointer, error) { if data == nil { if m.keySize == 0 { // Queues have a key length of zero, so passing nil here is valid. return internal.NewPointer(nil), nil } return internal.Pointer{}, errors.New("can't use nil as key of map") } return marshalPtr(data, int(m.keySize)) } func (m *Map) unmarshalKey(data interface{}, buf []byte) error { if buf == nil { // This is from a makeBuffer call, nothing do do here. return nil } return unmarshalBytes(data, buf) } func (m *Map) marshalValue(data interface{}) (internal.Pointer, error) { if m.typ.hasPerCPUValue() { return marshalPerCPUValue(data, int(m.valueSize)) } var ( buf []byte err error ) switch value := data.(type) { case *Map: if !m.typ.canStoreMap() { return internal.Pointer{}, fmt.Errorf("can't store map in %s", m.typ) } buf, err = marshalMap(value, int(m.valueSize)) case *Program: if !m.typ.canStoreProgram() { return internal.Pointer{}, fmt.Errorf("can't store program in %s", m.typ) } buf, err = marshalProgram(value, int(m.valueSize)) default: return marshalPtr(data, int(m.valueSize)) } if err != nil { return internal.Pointer{}, err } return internal.NewSlicePointer(buf), nil } func (m *Map) unmarshalValue(value interface{}, buf []byte) error { if buf == nil { // This is from a makeBuffer call, nothing do do here. return nil } if m.typ.hasPerCPUValue() { return unmarshalPerCPUValue(value, int(m.valueSize), buf) } switch value := value.(type) { case **Map: if !m.typ.canStoreMap() { return fmt.Errorf("can't read a map from %s", m.typ) } other, err := unmarshalMap(buf) if err != nil { return err } // The caller might close the map externally, so ignore errors. _ = (*value).Close() *value = other return nil case *Map: if !m.typ.canStoreMap() { return fmt.Errorf("can't read a map from %s", m.typ) } return errors.New("require pointer to *Map") case **Program: if !m.typ.canStoreProgram() { return fmt.Errorf("can't read a program from %s", m.typ) } other, err := unmarshalProgram(buf) if err != nil { return err } // The caller might close the program externally, so ignore errors. _ = (*value).Close() *value = other return nil case *Program: if !m.typ.canStoreProgram() { return fmt.Errorf("can't read a program from %s", m.typ) } return errors.New("require pointer to *Program") } return unmarshalBytes(value, buf) } // LoadPinnedMap loads a Map from a BPF file. func LoadPinnedMap(fileName string, opts *LoadPinOptions) (*Map, error) { fd, err := internal.BPFObjGet(fileName, opts.Marshal()) if err != nil { return nil, err } m, err := newMapFromFD(fd) if err == nil { m.pinnedPath = fileName } return m, err } // unmarshalMap creates a map from a map ID encoded in host endianness. func unmarshalMap(buf []byte) (*Map, error) { if len(buf) != 4 { return nil, errors.New("map id requires 4 byte value") } id := internal.NativeEndian.Uint32(buf) return NewMapFromID(MapID(id)) } // marshalMap marshals the fd of a map into a buffer in host endianness. func marshalMap(m *Map, length int) ([]byte, error) { if length != 4 { return nil, fmt.Errorf("can't marshal map to %d bytes", length) } fd, err := m.fd.Value() if err != nil { return nil, err } buf := make([]byte, 4) internal.NativeEndian.PutUint32(buf, fd) return buf, nil } func patchValue(value []byte, typ btf.Type, replacements map[string]interface{}) error { replaced := make(map[string]bool) replace := func(name string, offset, size int, replacement interface{}) error { if offset+size > len(value) { return fmt.Errorf("%s: offset %d(+%d) is out of bounds", name, offset, size) } buf, err := marshalBytes(replacement, size) if err != nil { return fmt.Errorf("marshal %s: %w", name, err) } copy(value[offset:offset+size], buf) replaced[name] = true return nil } switch parent := typ.(type) { case *btf.Datasec: for _, secinfo := range parent.Vars { name := string(secinfo.Type.(*btf.Var).Name) replacement, ok := replacements[name] if !ok { continue } err := replace(name, int(secinfo.Offset), int(secinfo.Size), replacement) if err != nil { return err } } default: return fmt.Errorf("patching %T is not supported", typ) } if len(replaced) == len(replacements) { return nil } var missing []string for name := range replacements { if !replaced[name] { missing = append(missing, name) } } if len(missing) == 1 { return fmt.Errorf("unknown field: %s", missing[0]) } return fmt.Errorf("unknown fields: %s", strings.Join(missing, ",")) } // MapIterator iterates a Map. // // See Map.Iterate. type MapIterator struct { target *Map prevKey interface{} prevBytes []byte count, maxEntries uint32 done bool err error } func newMapIterator(target *Map) *MapIterator { return &MapIterator{ target: target, maxEntries: target.maxEntries, prevBytes: make([]byte, target.keySize), } } // Next decodes the next key and value. // // Iterating a hash map from which keys are being deleted is not // safe. You may see the same key multiple times. Iteration may // also abort with an error, see IsIterationAborted. // // Returns false if there are no more entries. You must check // the result of Err afterwards. // // See Map.Get for further caveats around valueOut. func (mi *MapIterator) Next(keyOut, valueOut interface{}) bool { if mi.err != nil || mi.done { return false } // For array-like maps NextKeyBytes returns nil only on after maxEntries // iterations. for mi.count <= mi.maxEntries { var nextBytes []byte nextBytes, mi.err = mi.target.NextKeyBytes(mi.prevKey) if mi.err != nil { return false } if nextBytes == nil { mi.done = true return false } // The user can get access to nextBytes since unmarshalBytes // does not copy when unmarshaling into a []byte. // Make a copy to prevent accidental corruption of // iterator state. copy(mi.prevBytes, nextBytes) mi.prevKey = mi.prevBytes mi.count++ mi.err = mi.target.Lookup(nextBytes, valueOut) if errors.Is(mi.err, ErrKeyNotExist) { // Even though the key should be valid, we couldn't look up // its value. If we're iterating a hash map this is probably // because a concurrent delete removed the value before we // could get it. This means that the next call to NextKeyBytes // is very likely to restart iteration. // If we're iterating one of the fd maps like // ProgramArray it means that a given slot doesn't have // a valid fd associated. It's OK to continue to the next slot. continue } if mi.err != nil { return false } mi.err = mi.target.unmarshalKey(keyOut, nextBytes) return mi.err == nil } mi.err = fmt.Errorf("%w", ErrIterationAborted) return false } // Err returns any encountered error. // // The method must be called after Next returns nil. // // Returns ErrIterationAborted if it wasn't possible to do a full iteration. func (mi *MapIterator) Err() error { return mi.err } // MapGetNextID returns the ID of the next eBPF map. // // Returns ErrNotExist, if there is no next eBPF map. func MapGetNextID(startID MapID) (MapID, error) { id, err := objGetNextID(internal.BPF_MAP_GET_NEXT_ID, uint32(startID)) return MapID(id), err } // NewMapFromID returns the map for a given id. // // Returns ErrNotExist, if there is no eBPF map with the given id. func NewMapFromID(id MapID) (*Map, error) { fd, err := bpfObjGetFDByID(internal.BPF_MAP_GET_FD_BY_ID, uint32(id)) if err != nil { return nil, err } return newMapFromFD(fd) } // ID returns the systemwide unique ID of the map. // // Deprecated: use MapInfo.ID() instead. func (m *Map) ID() (MapID, error) { info, err := bpfGetMapInfoByFD(m.fd) if err != nil { return MapID(0), err } return MapID(info.id), nil }