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vendor: add d2g/dhcp4server

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This commit is contained in:
Dan Williams
2017-05-26 23:32:35 -05:00
parent 461d433911
commit 26ef6e312d
115 changed files with 13027 additions and 0 deletions
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41
vendor/golang.org/x/net/bpf/asm.go generated vendored Normal file
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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf
import "fmt"
// Assemble converts insts into raw instructions suitable for loading
// into a BPF virtual machine.
//
// Currently, no optimization is attempted, the assembled program flow
// is exactly as provided.
func Assemble(insts []Instruction) ([]RawInstruction, error) {
ret := make([]RawInstruction, len(insts))
var err error
for i, inst := range insts {
ret[i], err = inst.Assemble()
if err != nil {
return nil, fmt.Errorf("assembling instruction %d: %s", i+1, err)
}
}
return ret, nil
}
// Disassemble attempts to parse raw back into
// Instructions. Unrecognized RawInstructions are assumed to be an
// extension not implemented by this package, and are passed through
// unchanged to the output. The allDecoded value reports whether insts
// contains no RawInstructions.
func Disassemble(raw []RawInstruction) (insts []Instruction, allDecoded bool) {
insts = make([]Instruction, len(raw))
allDecoded = true
for i, r := range raw {
insts[i] = r.Disassemble()
if _, ok := insts[i].(RawInstruction); ok {
allDecoded = false
}
}
return insts, allDecoded
}

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf
// A Register is a register of the BPF virtual machine.
type Register uint16
const (
// RegA is the accumulator register. RegA is always the
// destination register of ALU operations.
RegA Register = iota
// RegX is the indirection register, used by LoadIndirect
// operations.
RegX
)
// An ALUOp is an arithmetic or logic operation.
type ALUOp uint16
// ALU binary operation types.
const (
ALUOpAdd ALUOp = iota << 4
ALUOpSub
ALUOpMul
ALUOpDiv
ALUOpOr
ALUOpAnd
ALUOpShiftLeft
ALUOpShiftRight
aluOpNeg // Not exported because it's the only unary ALU operation, and gets its own instruction type.
ALUOpMod
ALUOpXor
)
// A JumpTest is a comparison operator used in conditional jumps.
type JumpTest uint16
// Supported operators for conditional jumps.
const (
// K == A
JumpEqual JumpTest = iota
// K != A
JumpNotEqual
// K > A
JumpGreaterThan
// K < A
JumpLessThan
// K >= A
JumpGreaterOrEqual
// K <= A
JumpLessOrEqual
// K & A != 0
JumpBitsSet
// K & A == 0
JumpBitsNotSet
)
// An Extension is a function call provided by the kernel that
// performs advanced operations that are expensive or impossible
// within the BPF virtual machine.
//
// Extensions are only implemented by the Linux kernel.
//
// TODO: should we prune this list? Some of these extensions seem
// either broken or near-impossible to use correctly, whereas other
// (len, random, ifindex) are quite useful.
type Extension int
// Extension functions available in the Linux kernel.
const (
// ExtLen returns the length of the packet.
ExtLen Extension = 1
// ExtProto returns the packet's L3 protocol type.
ExtProto = 0
// ExtType returns the packet's type (skb->pkt_type in the kernel)
//
// TODO: better documentation. How nice an API do we want to
// provide for these esoteric extensions?
ExtType = 4
// ExtPayloadOffset returns the offset of the packet payload, or
// the first protocol header that the kernel does not know how to
// parse.
ExtPayloadOffset = 52
// ExtInterfaceIndex returns the index of the interface on which
// the packet was received.
ExtInterfaceIndex = 8
// ExtNetlinkAttr returns the netlink attribute of type X at
// offset A.
ExtNetlinkAttr = 12
// ExtNetlinkAttrNested returns the nested netlink attribute of
// type X at offset A.
ExtNetlinkAttrNested = 16
// ExtMark returns the packet's mark value.
ExtMark = 20
// ExtQueue returns the packet's assigned hardware queue.
ExtQueue = 24
// ExtLinkLayerType returns the packet's hardware address type
// (e.g. Ethernet, Infiniband).
ExtLinkLayerType = 28
// ExtRXHash returns the packets receive hash.
//
// TODO: figure out what this rxhash actually is.
ExtRXHash = 32
// ExtCPUID returns the ID of the CPU processing the current
// packet.
ExtCPUID = 36
// ExtVLANTag returns the packet's VLAN tag.
ExtVLANTag = 44
// ExtVLANTagPresent returns non-zero if the packet has a VLAN
// tag.
//
// TODO: I think this might be a lie: it reads bit 0x1000 of the
// VLAN header, which changed meaning in recent revisions of the
// spec - this extension may now return meaningless information.
ExtVLANTagPresent = 48
// ExtVLANProto returns 0x8100 if the frame has a VLAN header,
// 0x88a8 if the frame has a "Q-in-Q" double VLAN header, or some
// other value if no VLAN information is present.
ExtVLANProto = 60
// ExtRand returns a uniformly random uint32.
ExtRand = 56
)
// The following gives names to various bit patterns used in opcode construction.
const (
opMaskCls uint16 = 0x7
// opClsLoad masks
opMaskLoadDest = 0x01
opMaskLoadWidth = 0x18
opMaskLoadMode = 0xe0
// opClsALU
opMaskOperandSrc = 0x08
opMaskOperator = 0xf0
// opClsJump
opMaskJumpConst = 0x0f
opMaskJumpCond = 0xf0
)
const (
// +---------------+-----------------+---+---+---+
// | AddrMode (3b) | LoadWidth (2b) | 0 | 0 | 0 |
// +---------------+-----------------+---+---+---+
opClsLoadA uint16 = iota
// +---------------+-----------------+---+---+---+
// | AddrMode (3b) | LoadWidth (2b) | 0 | 0 | 1 |
// +---------------+-----------------+---+---+---+
opClsLoadX
// +---+---+---+---+---+---+---+---+
// | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
// +---+---+---+---+---+---+---+---+
opClsStoreA
// +---+---+---+---+---+---+---+---+
// | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
// +---+---+---+---+---+---+---+---+
opClsStoreX
// +---------------+-----------------+---+---+---+
// | Operator (4b) | OperandSrc (1b) | 1 | 0 | 0 |
// +---------------+-----------------+---+---+---+
opClsALU
// +-----------------------------+---+---+---+---+
// | TestOperator (4b) | 0 | 1 | 0 | 1 |
// +-----------------------------+---+---+---+---+
opClsJump
// +---+-------------------------+---+---+---+---+
// | 0 | 0 | 0 | RetSrc (1b) | 0 | 1 | 1 | 0 |
// +---+-------------------------+---+---+---+---+
opClsReturn
// +---+-------------------------+---+---+---+---+
// | 0 | 0 | 0 | TXAorTAX (1b) | 0 | 1 | 1 | 1 |
// +---+-------------------------+---+---+---+---+
opClsMisc
)
const (
opAddrModeImmediate uint16 = iota << 5
opAddrModeAbsolute
opAddrModeIndirect
opAddrModeScratch
opAddrModePacketLen // actually an extension, not an addressing mode.
opAddrModeMemShift
)
const (
opLoadWidth4 uint16 = iota << 3
opLoadWidth2
opLoadWidth1
)
// Operator defined by ALUOp*
const (
opALUSrcConstant uint16 = iota << 3
opALUSrcX
)
const (
opJumpAlways = iota << 4
opJumpEqual
opJumpGT
opJumpGE
opJumpSet
)
const (
opRetSrcConstant uint16 = iota << 4
opRetSrcA
)
const (
opMiscTAX = 0x00
opMiscTXA = 0x80
)

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
/*
Package bpf implements marshaling and unmarshaling of programs for the
Berkeley Packet Filter virtual machine, and provides a Go implementation
of the virtual machine.
BPF's main use is to specify a packet filter for network taps, so that
the kernel doesn't have to expensively copy every packet it sees to
userspace. However, it's been repurposed to other areas where running
user code in-kernel is needed. For example, Linux's seccomp uses BPF
to apply security policies to system calls. For simplicity, this
documentation refers only to packets, but other uses of BPF have their
own data payloads.
BPF programs run in a restricted virtual machine. It has almost no
access to kernel functions, and while conditional branches are
allowed, they can only jump forwards, to guarantee that there are no
infinite loops.
The virtual machine
The BPF VM is an accumulator machine. Its main register, called
register A, is an implicit source and destination in all arithmetic
and logic operations. The machine also has 16 scratch registers for
temporary storage, and an indirection register (register X) for
indirect memory access. All registers are 32 bits wide.
Each run of a BPF program is given one packet, which is placed in the
VM's read-only "main memory". LoadAbsolute and LoadIndirect
instructions can fetch up to 32 bits at a time into register A for
examination.
The goal of a BPF program is to produce and return a verdict (uint32),
which tells the kernel what to do with the packet. In the context of
packet filtering, the returned value is the number of bytes of the
packet to forward to userspace, or 0 to ignore the packet. Other
contexts like seccomp define their own return values.
In order to simplify programs, attempts to read past the end of the
packet terminate the program execution with a verdict of 0 (ignore
packet). This means that the vast majority of BPF programs don't need
to do any explicit bounds checking.
In addition to the bytes of the packet, some BPF programs have access
to extensions, which are essentially calls to kernel utility
functions. Currently, the only extensions supported by this package
are the Linux packet filter extensions.
Examples
This packet filter selects all ARP packets.
bpf.Assemble([]bpf.Instruction{
// Load "EtherType" field from the ethernet header.
bpf.LoadAbsolute{Off: 12, Size: 2},
// Skip over the next instruction if EtherType is not ARP.
bpf.JumpIf{Cond: bpf.JumpNotEqual, Val: 0x0806, SkipTrue: 1},
// Verdict is "send up to 4k of the packet to userspace."
bpf.RetConstant{Val: 4096},
// Verdict is "ignore packet."
bpf.RetConstant{Val: 0},
})
This packet filter captures a random 1% sample of traffic.
bpf.Assemble([]bpf.Instruction{
// Get a 32-bit random number from the Linux kernel.
bpf.LoadExtension{Num: bpf.ExtRand},
// 1% dice roll?
bpf.JumpIf{Cond: bpf.JumpLessThan, Val: 2^32/100, SkipFalse: 1},
// Capture.
bpf.RetConstant{Val: 4096},
// Ignore.
bpf.RetConstant{Val: 0},
})
*/
package bpf // import "golang.org/x/net/bpf"

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf
import "fmt"
// An Instruction is one instruction executed by the BPF virtual
// machine.
type Instruction interface {
// Assemble assembles the Instruction into a RawInstruction.
Assemble() (RawInstruction, error)
}
// A RawInstruction is a raw BPF virtual machine instruction.
type RawInstruction struct {
// Operation to execute.
Op uint16
// For conditional jump instructions, the number of instructions
// to skip if the condition is true/false.
Jt uint8
Jf uint8
// Constant parameter. The meaning depends on the Op.
K uint32
}
// Assemble implements the Instruction Assemble method.
func (ri RawInstruction) Assemble() (RawInstruction, error) { return ri, nil }
// Disassemble parses ri into an Instruction and returns it. If ri is
// not recognized by this package, ri itself is returned.
func (ri RawInstruction) Disassemble() Instruction {
switch ri.Op & opMaskCls {
case opClsLoadA, opClsLoadX:
reg := Register(ri.Op & opMaskLoadDest)
sz := 0
switch ri.Op & opMaskLoadWidth {
case opLoadWidth4:
sz = 4
case opLoadWidth2:
sz = 2
case opLoadWidth1:
sz = 1
default:
return ri
}
switch ri.Op & opMaskLoadMode {
case opAddrModeImmediate:
if sz != 4 {
return ri
}
return LoadConstant{Dst: reg, Val: ri.K}
case opAddrModeScratch:
if sz != 4 || ri.K > 15 {
return ri
}
return LoadScratch{Dst: reg, N: int(ri.K)}
case opAddrModeAbsolute:
return LoadAbsolute{Size: sz, Off: ri.K}
case opAddrModeIndirect:
return LoadIndirect{Size: sz, Off: ri.K}
case opAddrModePacketLen:
if sz != 4 {
return ri
}
return LoadExtension{Num: ExtLen}
case opAddrModeMemShift:
return LoadMemShift{Off: ri.K}
default:
return ri
}
case opClsStoreA:
if ri.Op != opClsStoreA || ri.K > 15 {
return ri
}
return StoreScratch{Src: RegA, N: int(ri.K)}
case opClsStoreX:
if ri.Op != opClsStoreX || ri.K > 15 {
return ri
}
return StoreScratch{Src: RegX, N: int(ri.K)}
case opClsALU:
switch op := ALUOp(ri.Op & opMaskOperator); op {
case ALUOpAdd, ALUOpSub, ALUOpMul, ALUOpDiv, ALUOpOr, ALUOpAnd, ALUOpShiftLeft, ALUOpShiftRight, ALUOpMod, ALUOpXor:
if ri.Op&opMaskOperandSrc != 0 {
return ALUOpX{Op: op}
}
return ALUOpConstant{Op: op, Val: ri.K}
case aluOpNeg:
return NegateA{}
default:
return ri
}
case opClsJump:
if ri.Op&opMaskJumpConst != opClsJump {
return ri
}
switch ri.Op & opMaskJumpCond {
case opJumpAlways:
return Jump{Skip: ri.K}
case opJumpEqual:
return JumpIf{
Cond: JumpEqual,
Val: ri.K,
SkipTrue: ri.Jt,
SkipFalse: ri.Jf,
}
case opJumpGT:
return JumpIf{
Cond: JumpGreaterThan,
Val: ri.K,
SkipTrue: ri.Jt,
SkipFalse: ri.Jf,
}
case opJumpGE:
return JumpIf{
Cond: JumpGreaterOrEqual,
Val: ri.K,
SkipTrue: ri.Jt,
SkipFalse: ri.Jf,
}
case opJumpSet:
return JumpIf{
Cond: JumpBitsSet,
Val: ri.K,
SkipTrue: ri.Jt,
SkipFalse: ri.Jf,
}
default:
return ri
}
case opClsReturn:
switch ri.Op {
case opClsReturn | opRetSrcA:
return RetA{}
case opClsReturn | opRetSrcConstant:
return RetConstant{Val: ri.K}
default:
return ri
}
case opClsMisc:
switch ri.Op {
case opClsMisc | opMiscTAX:
return TAX{}
case opClsMisc | opMiscTXA:
return TXA{}
default:
return ri
}
default:
panic("unreachable") // switch is exhaustive on the bit pattern
}
}
// LoadConstant loads Val into register Dst.
type LoadConstant struct {
Dst Register
Val uint32
}
// Assemble implements the Instruction Assemble method.
func (a LoadConstant) Assemble() (RawInstruction, error) {
return assembleLoad(a.Dst, 4, opAddrModeImmediate, a.Val)
}
// LoadScratch loads scratch[N] into register Dst.
type LoadScratch struct {
Dst Register
N int // 0-15
}
// Assemble implements the Instruction Assemble method.
func (a LoadScratch) Assemble() (RawInstruction, error) {
if a.N < 0 || a.N > 15 {
return RawInstruction{}, fmt.Errorf("invalid scratch slot %d", a.N)
}
return assembleLoad(a.Dst, 4, opAddrModeScratch, uint32(a.N))
}
// LoadAbsolute loads packet[Off:Off+Size] as an integer value into
// register A.
type LoadAbsolute struct {
Off uint32
Size int // 1, 2 or 4
}
// Assemble implements the Instruction Assemble method.
func (a LoadAbsolute) Assemble() (RawInstruction, error) {
return assembleLoad(RegA, a.Size, opAddrModeAbsolute, a.Off)
}
// LoadIndirect loads packet[X+Off:X+Off+Size] as an integer value
// into register A.
type LoadIndirect struct {
Off uint32
Size int // 1, 2 or 4
}
// Assemble implements the Instruction Assemble method.
func (a LoadIndirect) Assemble() (RawInstruction, error) {
return assembleLoad(RegA, a.Size, opAddrModeIndirect, a.Off)
}
// LoadMemShift multiplies the first 4 bits of the byte at packet[Off]
// by 4 and stores the result in register X.
//
// This instruction is mainly useful to load into X the length of an
// IPv4 packet header in a single instruction, rather than have to do
// the arithmetic on the header's first byte by hand.
type LoadMemShift struct {
Off uint32
}
// Assemble implements the Instruction Assemble method.
func (a LoadMemShift) Assemble() (RawInstruction, error) {
return assembleLoad(RegX, 1, opAddrModeMemShift, a.Off)
}
// LoadExtension invokes a linux-specific extension and stores the
// result in register A.
type LoadExtension struct {
Num Extension
}
// Assemble implements the Instruction Assemble method.
func (a LoadExtension) Assemble() (RawInstruction, error) {
if a.Num == ExtLen {
return assembleLoad(RegA, 4, opAddrModePacketLen, 0)
}
return assembleLoad(RegA, 4, opAddrModeAbsolute, uint32(-0x1000+a.Num))
}
// StoreScratch stores register Src into scratch[N].
type StoreScratch struct {
Src Register
N int // 0-15
}
// Assemble implements the Instruction Assemble method.
func (a StoreScratch) Assemble() (RawInstruction, error) {
if a.N < 0 || a.N > 15 {
return RawInstruction{}, fmt.Errorf("invalid scratch slot %d", a.N)
}
var op uint16
switch a.Src {
case RegA:
op = opClsStoreA
case RegX:
op = opClsStoreX
default:
return RawInstruction{}, fmt.Errorf("invalid source register %v", a.Src)
}
return RawInstruction{
Op: op,
K: uint32(a.N),
}, nil
}
// ALUOpConstant executes A = A <Op> Val.
type ALUOpConstant struct {
Op ALUOp
Val uint32
}
// Assemble implements the Instruction Assemble method.
func (a ALUOpConstant) Assemble() (RawInstruction, error) {
return RawInstruction{
Op: opClsALU | opALUSrcConstant | uint16(a.Op),
K: a.Val,
}, nil
}
// ALUOpX executes A = A <Op> X
type ALUOpX struct {
Op ALUOp
}
// Assemble implements the Instruction Assemble method.
func (a ALUOpX) Assemble() (RawInstruction, error) {
return RawInstruction{
Op: opClsALU | opALUSrcX | uint16(a.Op),
}, nil
}
// NegateA executes A = -A.
type NegateA struct{}
// Assemble implements the Instruction Assemble method.
func (a NegateA) Assemble() (RawInstruction, error) {
return RawInstruction{
Op: opClsALU | uint16(aluOpNeg),
}, nil
}
// Jump skips the following Skip instructions in the program.
type Jump struct {
Skip uint32
}
// Assemble implements the Instruction Assemble method.
func (a Jump) Assemble() (RawInstruction, error) {
return RawInstruction{
Op: opClsJump | opJumpAlways,
K: a.Skip,
}, nil
}
// JumpIf skips the following Skip instructions in the program if A
// <Cond> Val is true.
type JumpIf struct {
Cond JumpTest
Val uint32
SkipTrue uint8
SkipFalse uint8
}
// Assemble implements the Instruction Assemble method.
func (a JumpIf) Assemble() (RawInstruction, error) {
var (
cond uint16
flip bool
)
switch a.Cond {
case JumpEqual:
cond = opJumpEqual
case JumpNotEqual:
cond, flip = opJumpEqual, true
case JumpGreaterThan:
cond = opJumpGT
case JumpLessThan:
cond, flip = opJumpGE, true
case JumpGreaterOrEqual:
cond = opJumpGE
case JumpLessOrEqual:
cond, flip = opJumpGT, true
case JumpBitsSet:
cond = opJumpSet
case JumpBitsNotSet:
cond, flip = opJumpSet, true
default:
return RawInstruction{}, fmt.Errorf("unknown JumpTest %v", a.Cond)
}
jt, jf := a.SkipTrue, a.SkipFalse
if flip {
jt, jf = jf, jt
}
return RawInstruction{
Op: opClsJump | cond,
Jt: jt,
Jf: jf,
K: a.Val,
}, nil
}
// RetA exits the BPF program, returning the value of register A.
type RetA struct{}
// Assemble implements the Instruction Assemble method.
func (a RetA) Assemble() (RawInstruction, error) {
return RawInstruction{
Op: opClsReturn | opRetSrcA,
}, nil
}
// RetConstant exits the BPF program, returning a constant value.
type RetConstant struct {
Val uint32
}
// Assemble implements the Instruction Assemble method.
func (a RetConstant) Assemble() (RawInstruction, error) {
return RawInstruction{
Op: opClsReturn | opRetSrcConstant,
K: a.Val,
}, nil
}
// TXA copies the value of register X to register A.
type TXA struct{}
// Assemble implements the Instruction Assemble method.
func (a TXA) Assemble() (RawInstruction, error) {
return RawInstruction{
Op: opClsMisc | opMiscTXA,
}, nil
}
// TAX copies the value of register A to register X.
type TAX struct{}
// Assemble implements the Instruction Assemble method.
func (a TAX) Assemble() (RawInstruction, error) {
return RawInstruction{
Op: opClsMisc | opMiscTAX,
}, nil
}
func assembleLoad(dst Register, loadSize int, mode uint16, k uint32) (RawInstruction, error) {
var (
cls uint16
sz uint16
)
switch dst {
case RegA:
cls = opClsLoadA
case RegX:
cls = opClsLoadX
default:
return RawInstruction{}, fmt.Errorf("invalid target register %v", dst)
}
switch loadSize {
case 1:
sz = opLoadWidth1
case 2:
sz = opLoadWidth2
case 4:
sz = opLoadWidth4
default:
return RawInstruction{}, fmt.Errorf("invalid load byte length %d", sz)
}
return RawInstruction{
Op: cls | sz | mode,
K: k,
}, nil
}

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf
import (
"io/ioutil"
"reflect"
"strconv"
"strings"
"testing"
)
// This is a direct translation of the program in
// testdata/all_instructions.txt.
var allInstructions = []Instruction{
LoadConstant{Dst: RegA, Val: 42},
LoadConstant{Dst: RegX, Val: 42},
LoadScratch{Dst: RegA, N: 3},
LoadScratch{Dst: RegX, N: 3},
LoadAbsolute{Off: 42, Size: 1},
LoadAbsolute{Off: 42, Size: 2},
LoadAbsolute{Off: 42, Size: 4},
LoadIndirect{Off: 42, Size: 1},
LoadIndirect{Off: 42, Size: 2},
LoadIndirect{Off: 42, Size: 4},
LoadMemShift{Off: 42},
LoadExtension{Num: ExtLen},
LoadExtension{Num: ExtProto},
LoadExtension{Num: ExtType},
LoadExtension{Num: ExtRand},
StoreScratch{Src: RegA, N: 3},
StoreScratch{Src: RegX, N: 3},
ALUOpConstant{Op: ALUOpAdd, Val: 42},
ALUOpConstant{Op: ALUOpSub, Val: 42},
ALUOpConstant{Op: ALUOpMul, Val: 42},
ALUOpConstant{Op: ALUOpDiv, Val: 42},
ALUOpConstant{Op: ALUOpOr, Val: 42},
ALUOpConstant{Op: ALUOpAnd, Val: 42},
ALUOpConstant{Op: ALUOpShiftLeft, Val: 42},
ALUOpConstant{Op: ALUOpShiftRight, Val: 42},
ALUOpConstant{Op: ALUOpMod, Val: 42},
ALUOpConstant{Op: ALUOpXor, Val: 42},
ALUOpX{Op: ALUOpAdd},
ALUOpX{Op: ALUOpSub},
ALUOpX{Op: ALUOpMul},
ALUOpX{Op: ALUOpDiv},
ALUOpX{Op: ALUOpOr},
ALUOpX{Op: ALUOpAnd},
ALUOpX{Op: ALUOpShiftLeft},
ALUOpX{Op: ALUOpShiftRight},
ALUOpX{Op: ALUOpMod},
ALUOpX{Op: ALUOpXor},
NegateA{},
Jump{Skip: 10},
JumpIf{Cond: JumpEqual, Val: 42, SkipTrue: 8, SkipFalse: 9},
JumpIf{Cond: JumpNotEqual, Val: 42, SkipTrue: 8},
JumpIf{Cond: JumpLessThan, Val: 42, SkipTrue: 7},
JumpIf{Cond: JumpLessOrEqual, Val: 42, SkipTrue: 6},
JumpIf{Cond: JumpGreaterThan, Val: 42, SkipTrue: 4, SkipFalse: 5},
JumpIf{Cond: JumpGreaterOrEqual, Val: 42, SkipTrue: 3, SkipFalse: 4},
JumpIf{Cond: JumpBitsSet, Val: 42, SkipTrue: 2, SkipFalse: 3},
TAX{},
TXA{},
RetA{},
RetConstant{Val: 42},
}
var allInstructionsExpected = "testdata/all_instructions.bpf"
// Check that we produce the same output as the canonical bpf_asm
// linux kernel tool.
func TestInterop(t *testing.T) {
out, err := Assemble(allInstructions)
if err != nil {
t.Fatalf("assembly of allInstructions program failed: %s", err)
}
t.Logf("Assembled program is %d instructions long", len(out))
bs, err := ioutil.ReadFile(allInstructionsExpected)
if err != nil {
t.Fatalf("reading %s: %s", allInstructionsExpected, err)
}
// First statement is the number of statements, last statement is
// empty. We just ignore both and rely on slice length.
stmts := strings.Split(string(bs), ",")
if len(stmts)-2 != len(out) {
t.Fatalf("test program lengths don't match: %s has %d, Go implementation has %d", allInstructionsExpected, len(stmts)-2, len(allInstructions))
}
for i, stmt := range stmts[1 : len(stmts)-2] {
nums := strings.Split(stmt, " ")
if len(nums) != 4 {
t.Fatalf("malformed instruction %d in %s: %s", i+1, allInstructionsExpected, stmt)
}
actual := out[i]
op, err := strconv.ParseUint(nums[0], 10, 16)
if err != nil {
t.Fatalf("malformed opcode %s in instruction %d of %s", nums[0], i+1, allInstructionsExpected)
}
if actual.Op != uint16(op) {
t.Errorf("opcode mismatch on instruction %d (%#v): got 0x%02x, want 0x%02x", i+1, allInstructions[i], actual.Op, op)
}
jt, err := strconv.ParseUint(nums[1], 10, 8)
if err != nil {
t.Fatalf("malformed jt offset %s in instruction %d of %s", nums[1], i+1, allInstructionsExpected)
}
if actual.Jt != uint8(jt) {
t.Errorf("jt mismatch on instruction %d (%#v): got %d, want %d", i+1, allInstructions[i], actual.Jt, jt)
}
jf, err := strconv.ParseUint(nums[2], 10, 8)
if err != nil {
t.Fatalf("malformed jf offset %s in instruction %d of %s", nums[2], i+1, allInstructionsExpected)
}
if actual.Jf != uint8(jf) {
t.Errorf("jf mismatch on instruction %d (%#v): got %d, want %d", i+1, allInstructions[i], actual.Jf, jf)
}
k, err := strconv.ParseUint(nums[3], 10, 32)
if err != nil {
t.Fatalf("malformed constant %s in instruction %d of %s", nums[3], i+1, allInstructionsExpected)
}
if actual.K != uint32(k) {
t.Errorf("constant mismatch on instruction %d (%#v): got %d, want %d", i+1, allInstructions[i], actual.K, k)
}
}
}
// Check that assembly and disassembly match each other.
//
// Because we offer "fake" jump conditions that don't appear in the
// machine code, disassembly won't be a 1:1 match with the original
// source, although the behavior will be identical. However,
// reassembling the disassembly should produce an identical program.
func TestAsmDisasm(t *testing.T) {
prog1, err := Assemble(allInstructions)
if err != nil {
t.Fatalf("assembly of allInstructions program failed: %s", err)
}
t.Logf("Assembled program is %d instructions long", len(prog1))
src, allDecoded := Disassemble(prog1)
if !allDecoded {
t.Errorf("Disassemble(Assemble(allInstructions)) produced unrecognized instructions:")
for i, inst := range src {
if r, ok := inst.(RawInstruction); ok {
t.Logf(" insn %d, %#v --> %#v", i+1, allInstructions[i], r)
}
}
}
prog2, err := Assemble(src)
if err != nil {
t.Fatalf("assembly of Disassemble(Assemble(allInstructions)) failed: %s", err)
}
if len(prog2) != len(prog1) {
t.Fatalf("disassembly changed program size: %d insns before, %d insns after", len(prog1), len(prog2))
}
if !reflect.DeepEqual(prog1, prog2) {
t.Errorf("program mutated by disassembly:")
for i := range prog2 {
if !reflect.DeepEqual(prog1[i], prog2[i]) {
t.Logf(" insn %d, s: %#v, p1: %#v, p2: %#v", i+1, allInstructions[i], prog1[i], prog2[i])
}
}
}
}

1
vendor/golang.org/x/net/bpf/testdata/all_instructions.bpf generated vendored Normal file
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@ -0,0 +1 @@
50,0 0 0 42,1 0 0 42,96 0 0 3,97 0 0 3,48 0 0 42,40 0 0 42,32 0 0 42,80 0 0 42,72 0 0 42,64 0 0 42,177 0 0 42,128 0 0 0,32 0 0 4294963200,32 0 0 4294963204,32 0 0 4294963256,2 0 0 3,3 0 0 3,4 0 0 42,20 0 0 42,36 0 0 42,52 0 0 42,68 0 0 42,84 0 0 42,100 0 0 42,116 0 0 42,148 0 0 42,164 0 0 42,12 0 0 0,28 0 0 0,44 0 0 0,60 0 0 0,76 0 0 0,92 0 0 0,108 0 0 0,124 0 0 0,156 0 0 0,172 0 0 0,132 0 0 0,5 0 0 10,21 8 9 42,21 0 8 42,53 0 7 42,37 0 6 42,37 4 5 42,53 3 4 42,69 2 3 42,7 0 0 0,135 0 0 0,22 0 0 0,6 0 0 0,

79
vendor/golang.org/x/net/bpf/testdata/all_instructions.txt generated vendored Normal file
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@ -0,0 +1,79 @@
# This filter is compiled to all_instructions.bpf by the `bpf_asm`
# tool, which can be found in the linux kernel source tree under
# tools/net.
# Load immediate
ld #42
ldx #42
# Load scratch
ld M[3]
ldx M[3]
# Load absolute
ldb [42]
ldh [42]
ld [42]
# Load indirect
ldb [x + 42]
ldh [x + 42]
ld [x + 42]
# Load IPv4 header length
ldx 4*([42]&0xf)
# Run extension function
ld #len
ld #proto
ld #type
ld #rand
# Store scratch
st M[3]
stx M[3]
# A <op> constant
add #42
sub #42
mul #42
div #42
or #42
and #42
lsh #42
rsh #42
mod #42
xor #42
# A <op> X
add x
sub x
mul x
div x
or x
and x
lsh x
rsh x
mod x
xor x
# !A
neg
# Jumps
ja end
jeq #42,prev,end
jne #42,end
jlt #42,end
jle #42,end
jgt #42,prev,end
jge #42,prev,end
jset #42,prev,end
# Register transfers
tax
txa
# Returns
prev: ret a
end: ret #42

140
vendor/golang.org/x/net/bpf/vm.go generated vendored Normal file
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@ -0,0 +1,140 @@
// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf
import (
"errors"
"fmt"
)
// A VM is an emulated BPF virtual machine.
type VM struct {
filter []Instruction
}
// NewVM returns a new VM using the input BPF program.
func NewVM(filter []Instruction) (*VM, error) {
if len(filter) == 0 {
return nil, errors.New("one or more Instructions must be specified")
}
for i, ins := range filter {
check := len(filter) - (i + 1)
switch ins := ins.(type) {
// Check for out-of-bounds jumps in instructions
case Jump:
if check <= int(ins.Skip) {
return nil, fmt.Errorf("cannot jump %d instructions; jumping past program bounds", ins.Skip)
}
case JumpIf:
if check <= int(ins.SkipTrue) {
return nil, fmt.Errorf("cannot jump %d instructions in true case; jumping past program bounds", ins.SkipTrue)
}
if check <= int(ins.SkipFalse) {
return nil, fmt.Errorf("cannot jump %d instructions in false case; jumping past program bounds", ins.SkipFalse)
}
// Check for division or modulus by zero
case ALUOpConstant:
if ins.Val != 0 {
break
}
switch ins.Op {
case ALUOpDiv, ALUOpMod:
return nil, errors.New("cannot divide by zero using ALUOpConstant")
}
// Check for unknown extensions
case LoadExtension:
switch ins.Num {
case ExtLen:
default:
return nil, fmt.Errorf("extension %d not implemented", ins.Num)
}
}
}
// Make sure last instruction is a return instruction
switch filter[len(filter)-1].(type) {
case RetA, RetConstant:
default:
return nil, errors.New("BPF program must end with RetA or RetConstant")
}
// Though our VM works using disassembled instructions, we
// attempt to assemble the input filter anyway to ensure it is compatible
// with an operating system VM.
_, err := Assemble(filter)
return &VM{
filter: filter,
}, err
}
// Run runs the VM's BPF program against the input bytes.
// Run returns the number of bytes accepted by the BPF program, and any errors
// which occurred while processing the program.
func (v *VM) Run(in []byte) (int, error) {
var (
// Registers of the virtual machine
regA uint32
regX uint32
regScratch [16]uint32
// OK is true if the program should continue processing the next
// instruction, or false if not, causing the loop to break
ok = true
)
// TODO(mdlayher): implement:
// - NegateA:
// - would require a change from uint32 registers to int32
// registers
// TODO(mdlayher): add interop tests that check signedness of ALU
// operations against kernel implementation, and make sure Go
// implementation matches behavior
for i := 0; i < len(v.filter) && ok; i++ {
ins := v.filter[i]
switch ins := ins.(type) {
case ALUOpConstant:
regA = aluOpConstant(ins, regA)
case ALUOpX:
regA, ok = aluOpX(ins, regA, regX)
case Jump:
i += int(ins.Skip)
case JumpIf:
jump := jumpIf(ins, regA)
i += jump
case LoadAbsolute:
regA, ok = loadAbsolute(ins, in)
case LoadConstant:
regA, regX = loadConstant(ins, regA, regX)
case LoadExtension:
regA = loadExtension(ins, in)
case LoadIndirect:
regA, ok = loadIndirect(ins, in, regX)
case LoadMemShift:
regX, ok = loadMemShift(ins, in)
case LoadScratch:
regA, regX = loadScratch(ins, regScratch, regA, regX)
case RetA:
return int(regA), nil
case RetConstant:
return int(ins.Val), nil
case StoreScratch:
regScratch = storeScratch(ins, regScratch, regA, regX)
case TAX:
regX = regA
case TXA:
regA = regX
default:
return 0, fmt.Errorf("unknown Instruction at index %d: %T", i, ins)
}
}
return 0, nil
}

512
vendor/golang.org/x/net/bpf/vm_aluop_test.go generated vendored Normal file
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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf_test
import (
"testing"
"golang.org/x/net/bpf"
)
func TestVMALUOpAdd(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpAdd,
Val: 3,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
8, 2, 3,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 3, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpSub(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.TAX{},
bpf.ALUOpX{
Op: bpf.ALUOpSub,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
1, 2, 3,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpMul(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpMul,
Val: 2,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
6, 2, 3, 4,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 4, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpDiv(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpDiv,
Val: 2,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
20, 2, 3, 4,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 2, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpDivByZeroALUOpConstant(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.ALUOpConstant{
Op: bpf.ALUOpDiv,
Val: 0,
},
bpf.RetA{},
})
if errStr(err) != "cannot divide by zero using ALUOpConstant" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMALUOpDivByZeroALUOpX(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
// Load byte 0 into X
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.TAX{},
// Load byte 1 into A
bpf.LoadAbsolute{
Off: 9,
Size: 1,
},
// Attempt to perform 1/0
bpf.ALUOpX{
Op: bpf.ALUOpDiv,
},
// Return 4 bytes if program does not terminate
bpf.LoadConstant{
Val: 12,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1, 3, 4,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpOr(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 2,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpOr,
Val: 0x01,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0x00, 0x10, 0x03, 0x04,
0x05, 0x06, 0x07, 0x08,
0x09, 0xff,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 9, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpAnd(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 2,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpAnd,
Val: 0x0019,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0xaa, 0x09,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpShiftLeft(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpShiftLeft,
Val: 0x01,
},
bpf.JumpIf{
Cond: bpf.JumpEqual,
Val: 0x02,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 9,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0x01, 0xaa,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpShiftRight(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpShiftRight,
Val: 0x01,
},
bpf.JumpIf{
Cond: bpf.JumpEqual,
Val: 0x04,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 9,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0x08, 0xff, 0xff,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpMod(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpMod,
Val: 20,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
30, 0, 0,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 2, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpModByZeroALUOpConstant(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpMod,
Val: 0,
},
bpf.RetA{},
})
if errStr(err) != "cannot divide by zero using ALUOpConstant" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMALUOpModByZeroALUOpX(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
// Load byte 0 into X
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.TAX{},
// Load byte 1 into A
bpf.LoadAbsolute{
Off: 9,
Size: 1,
},
// Attempt to perform 1%0
bpf.ALUOpX{
Op: bpf.ALUOpMod,
},
// Return 4 bytes if program does not terminate
bpf.LoadConstant{
Val: 12,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1, 3, 4,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpXor(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpXor,
Val: 0x0a,
},
bpf.JumpIf{
Cond: bpf.JumpEqual,
Val: 0x01,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 9,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0x0b, 0x00, 0x00, 0x00,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMALUOpUnknown(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.ALUOpConstant{
Op: bpf.ALUOpAdd,
Val: 1,
},
// Verify that an unknown operation is a no-op
bpf.ALUOpConstant{
Op: 100,
},
bpf.JumpIf{
Cond: bpf.JumpEqual,
Val: 0x02,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 9,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
1,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}

192
vendor/golang.org/x/net/bpf/vm_bpf_test.go generated vendored Normal file
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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf_test
import (
"net"
"runtime"
"testing"
"time"
"golang.org/x/net/bpf"
"golang.org/x/net/ipv4"
)
// A virtualMachine is a BPF virtual machine which can process an
// input packet against a BPF program and render a verdict.
type virtualMachine interface {
Run(in []byte) (int, error)
}
// canUseOSVM indicates if the OS BPF VM is available on this platform.
func canUseOSVM() bool {
// OS BPF VM can only be used on platforms where x/net/ipv4 supports
// attaching a BPF program to a socket.
switch runtime.GOOS {
case "linux":
return true
}
return false
}
// All BPF tests against both the Go VM and OS VM are assumed to
// be used with a UDP socket. As a result, the entire contents
// of a UDP datagram is sent through the BPF program, but only
// the body after the UDP header will ever be returned in output.
// testVM sets up a Go BPF VM, and if available, a native OS BPF VM
// for integration testing.
func testVM(t *testing.T, filter []bpf.Instruction) (virtualMachine, func(), error) {
goVM, err := bpf.NewVM(filter)
if err != nil {
// Some tests expect an error, so this error must be returned
// instead of fatally exiting the test
return nil, nil, err
}
mvm := &multiVirtualMachine{
goVM: goVM,
t: t,
}
// If available, add the OS VM for tests which verify that both the Go
// VM and OS VM have exactly the same output for the same input program
// and packet.
done := func() {}
if canUseOSVM() {
osVM, osVMDone := testOSVM(t, filter)
done = func() { osVMDone() }
mvm.osVM = osVM
}
return mvm, done, nil
}
// udpHeaderLen is the length of a UDP header.
const udpHeaderLen = 8
// A multiVirtualMachine is a virtualMachine which can call out to both the Go VM
// and the native OS VM, if the OS VM is available.
type multiVirtualMachine struct {
goVM virtualMachine
osVM virtualMachine
t *testing.T
}
func (mvm *multiVirtualMachine) Run(in []byte) (int, error) {
if len(in) < udpHeaderLen {
mvm.t.Fatalf("input must be at least length of UDP header (%d), got: %d",
udpHeaderLen, len(in))
}
// All tests have a UDP header as part of input, because the OS VM
// packets always will. For the Go VM, this output is trimmed before
// being sent back to tests.
goOut, goErr := mvm.goVM.Run(in)
if goOut >= udpHeaderLen {
goOut -= udpHeaderLen
}
// If Go output is larger than the size of the packet, packet filtering
// interop tests must trim the output bytes to the length of the packet.
// The BPF VM should not do this on its own, as other uses of it do
// not trim the output byte count.
trim := len(in) - udpHeaderLen
if goOut > trim {
goOut = trim
}
// When the OS VM is not available, process using the Go VM alone
if mvm.osVM == nil {
return goOut, goErr
}
// The OS VM will apply its own UDP header, so remove the pseudo header
// that the Go VM needs.
osOut, err := mvm.osVM.Run(in[udpHeaderLen:])
if err != nil {
mvm.t.Fatalf("error while running OS VM: %v", err)
}
// Verify both VMs return same number of bytes
var mismatch bool
if goOut != osOut {
mismatch = true
mvm.t.Logf("output byte count does not match:\n- go: %v\n- os: %v", goOut, osOut)
}
if mismatch {
mvm.t.Fatal("Go BPF and OS BPF packet outputs do not match")
}
return goOut, goErr
}
// An osVirtualMachine is a virtualMachine which uses the OS's BPF VM for
// processing BPF programs.
type osVirtualMachine struct {
l net.PacketConn
s net.Conn
}
// testOSVM creates a virtualMachine which uses the OS's BPF VM by injecting
// packets into a UDP listener with a BPF program attached to it.
func testOSVM(t *testing.T, filter []bpf.Instruction) (virtualMachine, func()) {
l, err := net.ListenPacket("udp4", "127.0.0.1:0")
if err != nil {
t.Fatalf("failed to open OS VM UDP listener: %v", err)
}
prog, err := bpf.Assemble(filter)
if err != nil {
t.Fatalf("failed to compile BPF program: %v", err)
}
p := ipv4.NewPacketConn(l)
if err = p.SetBPF(prog); err != nil {
t.Fatalf("failed to attach BPF program to listener: %v", err)
}
s, err := net.Dial("udp4", l.LocalAddr().String())
if err != nil {
t.Fatalf("failed to dial connection to listener: %v", err)
}
done := func() {
_ = s.Close()
_ = l.Close()
}
return &osVirtualMachine{
l: l,
s: s,
}, done
}
// Run sends the input bytes into the OS's BPF VM and returns its verdict.
func (vm *osVirtualMachine) Run(in []byte) (int, error) {
go func() {
_, _ = vm.s.Write(in)
}()
vm.l.SetDeadline(time.Now().Add(50 * time.Millisecond))
var b [512]byte
n, _, err := vm.l.ReadFrom(b[:])
if err != nil {
// A timeout indicates that BPF filtered out the packet, and thus,
// no input should be returned.
if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
return n, nil
}
return n, err
}
return n, nil
}

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vendor/golang.org/x/net/bpf/vm_extension_test.go generated vendored Normal file
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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf_test
import (
"testing"
"golang.org/x/net/bpf"
)
func TestVMLoadExtensionNotImplemented(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.LoadExtension{
Num: 100,
},
bpf.RetA{},
})
if errStr(err) != "extension 100 not implemented" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMLoadExtensionExtLen(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadExtension{
Num: bpf.ExtLen,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1, 2, 3,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 4, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}

174
vendor/golang.org/x/net/bpf/vm_instructions.go generated vendored Normal file
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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf
import (
"encoding/binary"
"fmt"
)
func aluOpConstant(ins ALUOpConstant, regA uint32) uint32 {
return aluOpCommon(ins.Op, regA, ins.Val)
}
func aluOpX(ins ALUOpX, regA uint32, regX uint32) (uint32, bool) {
// Guard against division or modulus by zero by terminating
// the program, as the OS BPF VM does
if regX == 0 {
switch ins.Op {
case ALUOpDiv, ALUOpMod:
return 0, false
}
}
return aluOpCommon(ins.Op, regA, regX), true
}
func aluOpCommon(op ALUOp, regA uint32, value uint32) uint32 {
switch op {
case ALUOpAdd:
return regA + value
case ALUOpSub:
return regA - value
case ALUOpMul:
return regA * value
case ALUOpDiv:
// Division by zero not permitted by NewVM and aluOpX checks
return regA / value
case ALUOpOr:
return regA | value
case ALUOpAnd:
return regA & value
case ALUOpShiftLeft:
return regA << value
case ALUOpShiftRight:
return regA >> value
case ALUOpMod:
// Modulus by zero not permitted by NewVM and aluOpX checks
return regA % value
case ALUOpXor:
return regA ^ value
default:
return regA
}
}
func jumpIf(ins JumpIf, value uint32) int {
var ok bool
inV := uint32(ins.Val)
switch ins.Cond {
case JumpEqual:
ok = value == inV
case JumpNotEqual:
ok = value != inV
case JumpGreaterThan:
ok = value > inV
case JumpLessThan:
ok = value < inV
case JumpGreaterOrEqual:
ok = value >= inV
case JumpLessOrEqual:
ok = value <= inV
case JumpBitsSet:
ok = (value & inV) != 0
case JumpBitsNotSet:
ok = (value & inV) == 0
}
if ok {
return int(ins.SkipTrue)
}
return int(ins.SkipFalse)
}
func loadAbsolute(ins LoadAbsolute, in []byte) (uint32, bool) {
offset := int(ins.Off)
size := int(ins.Size)
return loadCommon(in, offset, size)
}
func loadConstant(ins LoadConstant, regA uint32, regX uint32) (uint32, uint32) {
switch ins.Dst {
case RegA:
regA = ins.Val
case RegX:
regX = ins.Val
}
return regA, regX
}
func loadExtension(ins LoadExtension, in []byte) uint32 {
switch ins.Num {
case ExtLen:
return uint32(len(in))
default:
panic(fmt.Sprintf("unimplemented extension: %d", ins.Num))
}
}
func loadIndirect(ins LoadIndirect, in []byte, regX uint32) (uint32, bool) {
offset := int(ins.Off) + int(regX)
size := int(ins.Size)
return loadCommon(in, offset, size)
}
func loadMemShift(ins LoadMemShift, in []byte) (uint32, bool) {
offset := int(ins.Off)
if !inBounds(len(in), offset, 0) {
return 0, false
}
// Mask off high 4 bits and multiply low 4 bits by 4
return uint32(in[offset]&0x0f) * 4, true
}
func inBounds(inLen int, offset int, size int) bool {
return offset+size <= inLen
}
func loadCommon(in []byte, offset int, size int) (uint32, bool) {
if !inBounds(len(in), offset, size) {
return 0, false
}
switch size {
case 1:
return uint32(in[offset]), true
case 2:
return uint32(binary.BigEndian.Uint16(in[offset : offset+size])), true
case 4:
return uint32(binary.BigEndian.Uint32(in[offset : offset+size])), true
default:
panic(fmt.Sprintf("invalid load size: %d", size))
}
}
func loadScratch(ins LoadScratch, regScratch [16]uint32, regA uint32, regX uint32) (uint32, uint32) {
switch ins.Dst {
case RegA:
regA = regScratch[ins.N]
case RegX:
regX = regScratch[ins.N]
}
return regA, regX
}
func storeScratch(ins StoreScratch, regScratch [16]uint32, regA uint32, regX uint32) [16]uint32 {
switch ins.Src {
case RegA:
regScratch[ins.N] = regA
case RegX:
regScratch[ins.N] = regX
}
return regScratch
}

380
vendor/golang.org/x/net/bpf/vm_jump_test.go generated vendored Normal file
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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf_test
import (
"testing"
"golang.org/x/net/bpf"
)
func TestVMJumpOne(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.Jump{
Skip: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 9,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
1,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMJumpOutOfProgram(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.Jump{
Skip: 1,
},
bpf.RetA{},
})
if errStr(err) != "cannot jump 1 instructions; jumping past program bounds" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMJumpIfTrueOutOfProgram(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.JumpIf{
Cond: bpf.JumpEqual,
SkipTrue: 2,
},
bpf.RetA{},
})
if errStr(err) != "cannot jump 2 instructions in true case; jumping past program bounds" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMJumpIfFalseOutOfProgram(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.JumpIf{
Cond: bpf.JumpEqual,
SkipFalse: 3,
},
bpf.RetA{},
})
if errStr(err) != "cannot jump 3 instructions in false case; jumping past program bounds" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMJumpIfEqual(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.JumpIf{
Cond: bpf.JumpEqual,
Val: 1,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 9,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
1,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMJumpIfNotEqual(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.JumpIf{
Cond: bpf.JumpNotEqual,
Val: 1,
SkipFalse: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 9,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
1,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMJumpIfGreaterThan(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 4,
},
bpf.JumpIf{
Cond: bpf.JumpGreaterThan,
Val: 0x00010202,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 12,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1, 2, 3,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 4, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMJumpIfLessThan(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 4,
},
bpf.JumpIf{
Cond: bpf.JumpLessThan,
Val: 0xff010203,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 12,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1, 2, 3,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 4, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMJumpIfGreaterOrEqual(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 4,
},
bpf.JumpIf{
Cond: bpf.JumpGreaterOrEqual,
Val: 0x00010203,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 12,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1, 2, 3,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 4, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMJumpIfLessOrEqual(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 4,
},
bpf.JumpIf{
Cond: bpf.JumpLessOrEqual,
Val: 0xff010203,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 12,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1, 2, 3,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 4, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMJumpIfBitsSet(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 2,
},
bpf.JumpIf{
Cond: bpf.JumpBitsSet,
Val: 0x1122,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 10,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0x01, 0x02,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 2, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMJumpIfBitsNotSet(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 2,
},
bpf.JumpIf{
Cond: bpf.JumpBitsNotSet,
Val: 0x1221,
SkipTrue: 1,
},
bpf.RetConstant{
Val: 0,
},
bpf.RetConstant{
Val: 10,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0x01, 0x02,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 2, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}

246
vendor/golang.org/x/net/bpf/vm_load_test.go generated vendored Normal file
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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf_test
import (
"net"
"testing"
"golang.org/x/net/bpf"
"golang.org/x/net/ipv4"
)
func TestVMLoadAbsoluteOffsetOutOfBounds(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 100,
Size: 2,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1, 2, 3,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadAbsoluteOffsetPlusSizeOutOfBounds(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 2,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadAbsoluteBadInstructionSize(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Size: 5,
},
bpf.RetA{},
})
if errStr(err) != "assembling instruction 1: invalid load byte length 0" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMLoadConstantOK(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadConstant{
Dst: bpf.RegX,
Val: 9,
},
bpf.TXA{},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadIndirectOutOfBounds(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadIndirect{
Off: 100,
Size: 1,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadMemShiftOutOfBounds(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadMemShift{
Off: 100,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
const (
dhcp4Port = 53
)
func TestVMLoadMemShiftLoadIndirectNoResult(t *testing.T) {
vm, in, done := testDHCPv4(t)
defer done()
// Append mostly empty UDP header with incorrect DHCPv4 port
in = append(in, []byte{
0, 0,
0, dhcp4Port + 1,
0, 0,
0, 0,
}...)
out, err := vm.Run(in)
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadMemShiftLoadIndirectOK(t *testing.T) {
vm, in, done := testDHCPv4(t)
defer done()
// Append mostly empty UDP header with correct DHCPv4 port
in = append(in, []byte{
0, 0,
0, dhcp4Port,
0, 0,
0, 0,
}...)
out, err := vm.Run(in)
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := len(in)-8, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func testDHCPv4(t *testing.T) (virtualMachine, []byte, func()) {
// DHCPv4 test data courtesy of David Anderson:
// https://github.com/google/netboot/blob/master/dhcp4/conn_linux.go#L59-L70
vm, done, err := testVM(t, []bpf.Instruction{
// Load IPv4 packet length
bpf.LoadMemShift{Off: 8},
// Get UDP dport
bpf.LoadIndirect{Off: 8 + 2, Size: 2},
// Correct dport?
bpf.JumpIf{Cond: bpf.JumpEqual, Val: dhcp4Port, SkipFalse: 1},
// Accept
bpf.RetConstant{Val: 1500},
// Ignore
bpf.RetConstant{Val: 0},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
// Minimal requirements to make a valid IPv4 header
h := &ipv4.Header{
Len: ipv4.HeaderLen,
Src: net.IPv4(192, 168, 1, 1),
Dst: net.IPv4(192, 168, 1, 2),
}
hb, err := h.Marshal()
if err != nil {
t.Fatalf("failed to marshal IPv4 header: %v", err)
}
hb = append([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
}, hb...)
return vm, hb, done
}

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf_test
import (
"testing"
"golang.org/x/net/bpf"
)
func TestVMRetA(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
9,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMRetALargerThanInput(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: 8,
Size: 2,
},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 255,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 2, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMRetConstant(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.RetConstant{
Val: 9,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMRetConstantLargerThanInput(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.RetConstant{
Val: 16,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 2, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf_test
import (
"testing"
"golang.org/x/net/bpf"
)
func TestVMStoreScratchInvalidScratchRegisterTooSmall(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.StoreScratch{
Src: bpf.RegA,
N: -1,
},
bpf.RetA{},
})
if errStr(err) != "assembling instruction 1: invalid scratch slot -1" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMStoreScratchInvalidScratchRegisterTooLarge(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.StoreScratch{
Src: bpf.RegA,
N: 16,
},
bpf.RetA{},
})
if errStr(err) != "assembling instruction 1: invalid scratch slot 16" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMStoreScratchUnknownSourceRegister(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.StoreScratch{
Src: 100,
N: 0,
},
bpf.RetA{},
})
if errStr(err) != "assembling instruction 1: invalid source register 100" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMLoadScratchInvalidScratchRegisterTooSmall(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.LoadScratch{
Dst: bpf.RegX,
N: -1,
},
bpf.RetA{},
})
if errStr(err) != "assembling instruction 1: invalid scratch slot -1" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMLoadScratchInvalidScratchRegisterTooLarge(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.LoadScratch{
Dst: bpf.RegX,
N: 16,
},
bpf.RetA{},
})
if errStr(err) != "assembling instruction 1: invalid scratch slot 16" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMLoadScratchUnknownDestinationRegister(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.LoadScratch{
Dst: 100,
N: 0,
},
bpf.RetA{},
})
if errStr(err) != "assembling instruction 1: invalid target register 100" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMStoreScratchLoadScratchOneValue(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
// Load byte 255
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
// Copy to X and store in scratch[0]
bpf.TAX{},
bpf.StoreScratch{
Src: bpf.RegX,
N: 0,
},
// Load byte 1
bpf.LoadAbsolute{
Off: 9,
Size: 1,
},
// Overwrite 1 with 255 from scratch[0]
bpf.LoadScratch{
Dst: bpf.RegA,
N: 0,
},
// Return 255
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
255, 1, 2,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 3, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMStoreScratchLoadScratchMultipleValues(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
// Load byte 10
bpf.LoadAbsolute{
Off: 8,
Size: 1,
},
// Store in scratch[0]
bpf.StoreScratch{
Src: bpf.RegA,
N: 0,
},
// Load byte 20
bpf.LoadAbsolute{
Off: 9,
Size: 1,
},
// Store in scratch[1]
bpf.StoreScratch{
Src: bpf.RegA,
N: 1,
},
// Load byte 30
bpf.LoadAbsolute{
Off: 10,
Size: 1,
},
// Store in scratch[2]
bpf.StoreScratch{
Src: bpf.RegA,
N: 2,
},
// Load byte 1
bpf.LoadAbsolute{
Off: 11,
Size: 1,
},
// Store in scratch[3]
bpf.StoreScratch{
Src: bpf.RegA,
N: 3,
},
// Load in byte 10 to X
bpf.LoadScratch{
Dst: bpf.RegX,
N: 0,
},
// Copy X -> A
bpf.TXA{},
// Verify value is 10
bpf.JumpIf{
Cond: bpf.JumpEqual,
Val: 10,
SkipTrue: 1,
},
// Fail test if incorrect
bpf.RetConstant{
Val: 0,
},
// Load in byte 20 to A
bpf.LoadScratch{
Dst: bpf.RegA,
N: 1,
},
// Verify value is 20
bpf.JumpIf{
Cond: bpf.JumpEqual,
Val: 20,
SkipTrue: 1,
},
// Fail test if incorrect
bpf.RetConstant{
Val: 0,
},
// Load in byte 30 to A
bpf.LoadScratch{
Dst: bpf.RegA,
N: 2,
},
// Verify value is 30
bpf.JumpIf{
Cond: bpf.JumpEqual,
Val: 30,
SkipTrue: 1,
},
// Fail test if incorrect
bpf.RetConstant{
Val: 0,
},
// Return first two bytes on success
bpf.RetConstant{
Val: 10,
},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
10, 20, 30, 1,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 2, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf_test
import (
"fmt"
"testing"
"golang.org/x/net/bpf"
)
var _ bpf.Instruction = unknown{}
type unknown struct{}
func (unknown) Assemble() (bpf.RawInstruction, error) {
return bpf.RawInstruction{}, nil
}
func TestVMUnknownInstruction(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadConstant{
Dst: bpf.RegA,
Val: 100,
},
// Should terminate the program with an error immediately
unknown{},
bpf.RetA{},
})
if err != nil {
t.Fatalf("unexpected error: %v", err)
}
defer done()
_, err = vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0x00, 0x00,
})
if errStr(err) != "unknown Instruction at index 1: bpf_test.unknown" {
t.Fatalf("unexpected error while running program: %v", err)
}
}
func TestVMNoReturnInstruction(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.LoadConstant{
Dst: bpf.RegA,
Val: 1,
},
})
if errStr(err) != "BPF program must end with RetA or RetConstant" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMNoInputInstructions(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{})
if errStr(err) != "one or more Instructions must be specified" {
t.Fatalf("unexpected error: %v", err)
}
}
// ExampleNewVM demonstrates usage of a VM, using an Ethernet frame
// as input and checking its EtherType to determine if it should be accepted.
func ExampleNewVM() {
// Offset | Length | Comment
// -------------------------
// 00 | 06 | Ethernet destination MAC address
// 06 | 06 | Ethernet source MAC address
// 12 | 02 | Ethernet EtherType
const (
etOff = 12
etLen = 2
etARP = 0x0806
)
// Set up a VM to filter traffic based on if its EtherType
// matches the ARP EtherType.
vm, err := bpf.NewVM([]bpf.Instruction{
// Load EtherType value from Ethernet header
bpf.LoadAbsolute{
Off: etOff,
Size: etLen,
},
// If EtherType is equal to the ARP EtherType, jump to allow
// packet to be accepted
bpf.JumpIf{
Cond: bpf.JumpEqual,
Val: etARP,
SkipTrue: 1,
},
// EtherType does not match the ARP EtherType
bpf.RetConstant{
Val: 0,
},
// EtherType matches the ARP EtherType, accept up to 1500
// bytes of packet
bpf.RetConstant{
Val: 1500,
},
})
if err != nil {
panic(fmt.Sprintf("failed to load BPF program: %v", err))
}
// Create an Ethernet frame with the ARP EtherType for testing
frame := []byte{
0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0x00, 0x11, 0x22, 0x33, 0x44, 0x55,
0x08, 0x06,
// Payload omitted for brevity
}
// Run our VM's BPF program using the Ethernet frame as input
out, err := vm.Run(frame)
if err != nil {
panic(fmt.Sprintf("failed to accept Ethernet frame: %v", err))
}
// BPF VM can return a byte count greater than the number of input
// bytes, so trim the output to match the input byte length
if out > len(frame) {
out = len(frame)
}
fmt.Printf("out: %d bytes", out)
// Output:
// out: 14 bytes
}
// errStr returns the string representation of an error, or
// "<nil>" if it is nil.
func errStr(err error) string {
if err == nil {
return "<nil>"
}
return err.Error()
}