1 files changed, 498 insertions, 0 deletions
diff --git a/vendor/github.com/cilium/ebpf/asm/instruction.go b/vendor/github.com/cilium/ebpf/asm/instruction.go
new file mode 100644
index 000000000..5d9d820e5
--- /dev/null
+++ b/vendor/github.com/cilium/ebpf/asm/instruction.go
@@ -0,0 +1,498 @@
+package asm
+
+import (
+	"crypto/sha1"
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"math"
+	"strings"
+
+	"github.com/cilium/ebpf/internal/unix"
+)
+
+// InstructionSize is the size of a BPF instruction in bytes
+const InstructionSize = 8
+
+// RawInstructionOffset is an offset in units of raw BPF instructions.
+type RawInstructionOffset uint64
+
+// Bytes returns the offset of an instruction in bytes.
+func (rio RawInstructionOffset) Bytes() uint64 {
+	return uint64(rio) * InstructionSize
+}
+
+// Instruction is a single eBPF instruction.
+type Instruction struct {
+	OpCode    OpCode
+	Dst       Register
+	Src       Register
+	Offset    int16
+	Constant  int64
+	Reference string
+	Symbol    string
+}
+
+// Sym creates a symbol.
+func (ins Instruction) Sym(name string) Instruction {
+	ins.Symbol = name
+	return ins
+}
+
+// Unmarshal decodes a BPF instruction.
+func (ins *Instruction) Unmarshal(r io.Reader, bo binary.ByteOrder) (uint64, error) {
+	var bi bpfInstruction
+	err := binary.Read(r, bo, &bi)
+	if err != nil {
+		return 0, err
+	}
+
+	ins.OpCode = bi.OpCode
+	ins.Offset = bi.Offset
+	ins.Constant = int64(bi.Constant)
+	ins.Dst, ins.Src, err = bi.Registers.Unmarshal(bo)
+	if err != nil {
+		return 0, fmt.Errorf("can't unmarshal registers: %s", err)
+	}
+
+	if !bi.OpCode.isDWordLoad() {
+		return InstructionSize, nil
+	}
+
+	var bi2 bpfInstruction
+	if err := binary.Read(r, bo, &bi2); err != nil {
+		// No Wrap, to avoid io.EOF clash
+		return 0, errors.New("64bit immediate is missing second half")
+	}
+	if bi2.OpCode != 0 || bi2.Offset != 0 || bi2.Registers != 0 {
+		return 0, errors.New("64bit immediate has non-zero fields")
+	}
+	ins.Constant = int64(uint64(uint32(bi2.Constant))<<32 | uint64(uint32(bi.Constant)))
+
+	return 2 * InstructionSize, nil
+}
+
+// Marshal encodes a BPF instruction.
+func (ins Instruction) Marshal(w io.Writer, bo binary.ByteOrder) (uint64, error) {
+	if ins.OpCode == InvalidOpCode {
+		return 0, errors.New("invalid opcode")
+	}
+
+	isDWordLoad := ins.OpCode.isDWordLoad()
+
+	cons := int32(ins.Constant)
+	if isDWordLoad {
+		// Encode least significant 32bit first for 64bit operations.
+		cons = int32(uint32(ins.Constant))
+	}
+
+	regs, err := newBPFRegisters(ins.Dst, ins.Src, bo)
+	if err != nil {
+		return 0, fmt.Errorf("can't marshal registers: %s", err)
+	}
+
+	bpfi := bpfInstruction{
+		ins.OpCode,
+		regs,
+		ins.Offset,
+		cons,
+	}
+
+	if err := binary.Write(w, bo, &bpfi); err != nil {
+		return 0, err
+	}
+
+	if !isDWordLoad {
+		return InstructionSize, nil
+	}
+
+	bpfi = bpfInstruction{
+		Constant: int32(ins.Constant >> 32),
+	}
+
+	if err := binary.Write(w, bo, &bpfi); err != nil {
+		return 0, err
+	}
+
+	return 2 * InstructionSize, nil
+}
+
+// RewriteMapPtr changes an instruction to use a new map fd.
+//
+// Returns an error if the instruction doesn't load a map.
+func (ins *Instruction) RewriteMapPtr(fd int) error {
+	if !ins.OpCode.isDWordLoad() {
+		return fmt.Errorf("%s is not a 64 bit load", ins.OpCode)
+	}
+
+	if ins.Src != PseudoMapFD && ins.Src != PseudoMapValue {
+		return errors.New("not a load from a map")
+	}
+
+	// Preserve the offset value for direct map loads.
+	offset := uint64(ins.Constant) & (math.MaxUint32 << 32)
+	rawFd := uint64(uint32(fd))
+	ins.Constant = int64(offset | rawFd)
+	return nil
+}
+
+func (ins *Instruction) mapPtr() uint32 {
+	return uint32(uint64(ins.Constant) & math.MaxUint32)
+}
+
+// RewriteMapOffset changes the offset of a direct load from a map.
+//
+// Returns an error if the instruction is not a direct load.
+func (ins *Instruction) RewriteMapOffset(offset uint32) error {
+	if !ins.OpCode.isDWordLoad() {
+		return fmt.Errorf("%s is not a 64 bit load", ins.OpCode)
+	}
+
+	if ins.Src != PseudoMapValue {
+		return errors.New("not a direct load from a map")
+	}
+
+	fd := uint64(ins.Constant) & math.MaxUint32
+	ins.Constant = int64(uint64(offset)<<32 | fd)
+	return nil
+}
+
+func (ins *Instruction) mapOffset() uint32 {
+	return uint32(uint64(ins.Constant) >> 32)
+}
+
+// isLoadFromMap returns true if the instruction loads from a map.
+//
+// This covers both loading the map pointer and direct map value loads.
+func (ins *Instruction) isLoadFromMap() bool {
+	return ins.OpCode == LoadImmOp(DWord) && (ins.Src == PseudoMapFD || ins.Src == PseudoMapValue)
+}
+
+// IsFunctionCall returns true if the instruction calls another BPF function.
+//
+// This is not the same thing as a BPF helper call.
+func (ins *Instruction) IsFunctionCall() bool {
+	return ins.OpCode.JumpOp() == Call && ins.Src == PseudoCall
+}
+
+// Format implements fmt.Formatter.
+func (ins Instruction) Format(f fmt.State, c rune) {
+	if c != 'v' {
+		fmt.Fprintf(f, "{UNRECOGNIZED: %c}", c)
+		return
+	}
+
+	op := ins.OpCode
+
+	if op == InvalidOpCode {
+		fmt.Fprint(f, "INVALID")
+		return
+	}
+
+	// Omit trailing space for Exit
+	if op.JumpOp() == Exit {
+		fmt.Fprint(f, op)
+		return
+	}
+
+	if ins.isLoadFromMap() {
+		fd := int32(ins.mapPtr())
+		switch ins.Src {
+		case PseudoMapFD:
+			fmt.Fprintf(f, "LoadMapPtr dst: %s fd: %d", ins.Dst, fd)
+
+		case PseudoMapValue:
+			fmt.Fprintf(f, "LoadMapValue dst: %s, fd: %d off: %d", ins.Dst, fd, ins.mapOffset())
+		}
+
+		goto ref
+	}
+
+	fmt.Fprintf(f, "%v ", op)
+	switch cls := op.Class(); cls {
+	case LdClass, LdXClass, StClass, StXClass:
+		switch op.Mode() {
+		case ImmMode:
+			fmt.Fprintf(f, "dst: %s imm: %d", ins.Dst, ins.Constant)
+		case AbsMode:
+			fmt.Fprintf(f, "imm: %d", ins.Constant)
+		case IndMode:
+			fmt.Fprintf(f, "dst: %s src: %s imm: %d", ins.Dst, ins.Src, ins.Constant)
+		case MemMode:
+			fmt.Fprintf(f, "dst: %s src: %s off: %d imm: %d", ins.Dst, ins.Src, ins.Offset, ins.Constant)
+		case XAddMode:
+			fmt.Fprintf(f, "dst: %s src: %s", ins.Dst, ins.Src)
+		}
+
+	case ALU64Class, ALUClass:
+		fmt.Fprintf(f, "dst: %s ", ins.Dst)
+		if op.ALUOp() == Swap || op.Source() == ImmSource {
+			fmt.Fprintf(f, "imm: %d", ins.Constant)
+		} else {
+			fmt.Fprintf(f, "src: %s", ins.Src)
+		}
+
+	case JumpClass:
+		switch jop := op.JumpOp(); jop {
+		case Call:
+			if ins.Src == PseudoCall {
+				// bpf-to-bpf call
+				fmt.Fprint(f, ins.Constant)
+			} else {
+				fmt.Fprint(f, BuiltinFunc(ins.Constant))
+			}
+
+		default:
+			fmt.Fprintf(f, "dst: %s off: %d ", ins.Dst, ins.Offset)
+			if op.Source() == ImmSource {
+				fmt.Fprintf(f, "imm: %d", ins.Constant)
+			} else {
+				fmt.Fprintf(f, "src: %s", ins.Src)
+			}
+		}
+	}
+
+ref:
+	if ins.Reference != "" {
+		fmt.Fprintf(f, " <%s>", ins.Reference)
+	}
+}
+
+// Instructions is an eBPF program.
+type Instructions []Instruction
+
+func (insns Instructions) String() string {
+	return fmt.Sprint(insns)
+}
+
+// RewriteMapPtr rewrites all loads of a specific map pointer to a new fd.
+//
+// Returns an error if the symbol isn't used, see IsUnreferencedSymbol.
+func (insns Instructions) RewriteMapPtr(symbol string, fd int) error {
+	if symbol == "" {
+		return errors.New("empty symbol")
+	}
+
+	found := false
+	for i := range insns {
+		ins := &insns[i]
+		if ins.Reference != symbol {
+			continue
+		}
+
+		if err := ins.RewriteMapPtr(fd); err != nil {
+			return err
+		}
+
+		found = true
+	}
+
+	if !found {
+		return &unreferencedSymbolError{symbol}
+	}
+
+	return nil
+}
+
+// SymbolOffsets returns the set of symbols and their offset in
+// the instructions.
+func (insns Instructions) SymbolOffsets() (map[string]int, error) {
+	offsets := make(map[string]int)
+
+	for i, ins := range insns {
+		if ins.Symbol == "" {
+			continue
+		}
+
+		if _, ok := offsets[ins.Symbol]; ok {
+			return nil, fmt.Errorf("duplicate symbol %s", ins.Symbol)
+		}
+
+		offsets[ins.Symbol] = i
+	}
+
+	return offsets, nil
+}
+
+// ReferenceOffsets returns the set of references and their offset in
+// the instructions.
+func (insns Instructions) ReferenceOffsets() map[string][]int {
+	offsets := make(map[string][]int)
+
+	for i, ins := range insns {
+		if ins.Reference == "" {
+			continue
+		}
+
+		offsets[ins.Reference] = append(offsets[ins.Reference], i)
+	}
+
+	return offsets
+}
+
+// Format implements fmt.Formatter.
+//
+// You can control indentation of symbols by
+// specifying a width. Setting a precision controls the indentation of
+// instructions.
+// The default character is a tab, which can be overriden by specifying
+// the ' ' space flag.
+func (insns Instructions) Format(f fmt.State, c rune) {
+	if c != 's' && c != 'v' {
+		fmt.Fprintf(f, "{UNKNOWN FORMAT '%c'}", c)
+		return
+	}
+
+	// Precision is better in this case, because it allows
+	// specifying 0 padding easily.
+	padding, ok := f.Precision()
+	if !ok {
+		padding = 1
+	}
+
+	indent := strings.Repeat("\t", padding)
+	if f.Flag(' ') {
+		indent = strings.Repeat(" ", padding)
+	}
+
+	symPadding, ok := f.Width()
+	if !ok {
+		symPadding = padding - 1
+	}
+	if symPadding < 0 {
+		symPadding = 0
+	}
+
+	symIndent := strings.Repeat("\t", symPadding)
+	if f.Flag(' ') {
+		symIndent = strings.Repeat(" ", symPadding)
+	}
+
+	// Guess how many digits we need at most, by assuming that all instructions
+	// are double wide.
+	highestOffset := len(insns) * 2
+	offsetWidth := int(math.Ceil(math.Log10(float64(highestOffset))))
+
+	iter := insns.Iterate()
+	for iter.Next() {
+		if iter.Ins.Symbol != "" {
+			fmt.Fprintf(f, "%s%s:\n", symIndent, iter.Ins.Symbol)
+		}
+		fmt.Fprintf(f, "%s%*d: %v\n", indent, offsetWidth, iter.Offset, iter.Ins)
+	}
+
+	return
+}
+
+// Marshal encodes a BPF program into the kernel format.
+func (insns Instructions) Marshal(w io.Writer, bo binary.ByteOrder) error {
+	for i, ins := range insns {
+		_, err := ins.Marshal(w, bo)
+		if err != nil {
+			return fmt.Errorf("instruction %d: %w", i, err)
+		}
+	}
+	return nil
+}
+
+// Tag calculates the kernel tag for a series of instructions.
+//
+// It mirrors bpf_prog_calc_tag in the kernel and so can be compared
+// to ProgramInfo.Tag to figure out whether a loaded program matches
+// certain instructions.
+func (insns Instructions) Tag(bo binary.ByteOrder) (string, error) {
+	h := sha1.New()
+	for i, ins := range insns {
+		if ins.isLoadFromMap() {
+			ins.Constant = 0
+		}
+		_, err := ins.Marshal(h, bo)
+		if err != nil {
+			return "", fmt.Errorf("instruction %d: %w", i, err)
+		}
+	}
+	return hex.EncodeToString(h.Sum(nil)[:unix.BPF_TAG_SIZE]), nil
+}
+
+// Iterate allows iterating a BPF program while keeping track of
+// various offsets.
+//
+// Modifying the instruction slice will lead to undefined behaviour.
+func (insns Instructions) Iterate() *InstructionIterator {
+	return &InstructionIterator{insns: insns}
+}
+
+// InstructionIterator iterates over a BPF program.
+type InstructionIterator struct {
+	insns Instructions
+	// The instruction in question.
+	Ins *Instruction
+	// The index of the instruction in the original instruction slice.
+	Index int
+	// The offset of the instruction in raw BPF instructions. This accounts
+	// for double-wide instructions.
+	Offset RawInstructionOffset
+}
+
+// Next returns true as long as there are any instructions remaining.
+func (iter *InstructionIterator) Next() bool {
+	if len(iter.insns) == 0 {
+		return false
+	}
+
+	if iter.Ins != nil {
+		iter.Index++
+		iter.Offset += RawInstructionOffset(iter.Ins.OpCode.rawInstructions())
+	}
+	iter.Ins = &iter.insns[0]
+	iter.insns = iter.insns[1:]
+	return true
+}
+
+type bpfInstruction struct {
+	OpCode    OpCode
+	Registers bpfRegisters
+	Offset    int16
+	Constant  int32
+}
+
+type bpfRegisters uint8
+
+func newBPFRegisters(dst, src Register, bo binary.ByteOrder) (bpfRegisters, error) {
+	switch bo {
+	case binary.LittleEndian:
+		return bpfRegisters((src << 4) | (dst & 0xF)), nil
+	case binary.BigEndian:
+		return bpfRegisters((dst << 4) | (src & 0xF)), nil
+	default:
+		return 0, fmt.Errorf("unrecognized ByteOrder %T", bo)
+	}
+}
+
+func (r bpfRegisters) Unmarshal(bo binary.ByteOrder) (dst, src Register, err error) {
+	switch bo {
+	case binary.LittleEndian:
+		return Register(r & 0xF), Register(r >> 4), nil
+	case binary.BigEndian:
+		return Register(r >> 4), Register(r & 0xf), nil
+	default:
+		return 0, 0, fmt.Errorf("unrecognized ByteOrder %T", bo)
+	}
+}
+
+type unreferencedSymbolError struct {
+	symbol string
+}
+
+func (use *unreferencedSymbolError) Error() string {
+	return fmt.Sprintf("unreferenced symbol %s", use.symbol)
+}
+
+// IsUnreferencedSymbol returns true if err was caused by
+// an unreferenced symbol.
+func IsUnreferencedSymbol(err error) bool {
+	_, ok := err.(*unreferencedSymbolError)
+	return ok
+}