libbpfgo

README

libbpfgo

libbpfgo is a Go library that allows working with the Linux eBPF subsystem via libbpf. libbpf is a C library that's developed as part of the Linux kernel tree which provides an accessible layer of abstraction on top of the raw eBPF system APIs. libbpfgo is just a thin wrapper in Go around libbpf.

Installing

libbpfgo is using CGO to interop with libbpf and will expect to be linked with libbpf at run or link time. Simply importing libbpfgo is not enough to get started, and you will need to fulfill the required dependency in one of the following ways:

1. Install the libbpf as a shared object in the system. Libbpf may already be packaged for you distribution, if not, you can build and install from source. More info here.
2. Embed libbpf into your Go project as a vendored dependency. This means that the libbpf code is statically linked into the resulting binary, and there are no runtime dependencies. Tracee takes this approach and you can take example from it's Makefile.

Concepts

libbpfgo tries to make it natural for Go developers to use, by abstracting away C technicalities. For example, it will translate low level return codes into Go error, it will organize functionality around Go struct, and it will use channel as to let you consume events.

In a high level, this is a typical workflow for working with the library:

1. Compile your bpf program into an object file.
2. Initialize a Module struct - that is a unit of BPF functionality around your compiled object file.
3. Load bpf programs from the object file using the BPFProg struct.
4. Attach BPFProg to system facilities, for example to "raw tracepoints" or "kprobes" using the BPFProg's associated functions.
5. Instantiate and manipulate BPF Maps via the BPFMap struct and it's associated methods.
6. Instantiate and manipulate Perf Buffer for communicating events from your BPF program to the driving userspace program, using the PerfBuffer struct and it's associated objects.

Example

// initializing
import bpf "github.com/aquasecurity/tracee/libbpfgo"
...
bpfModule := bpf.NewModuleFromFile(bpfObjectPath)
bpfModule.BPFLoadObject()

// maps
mymap, _ := bpfModule.GetMap("mymap")
mymap.Update(key, value)

// perf buffer
pb, _ := bpfModule.InitPerfBuf("events", eventsChannel, lostEvChannel, buffSize)
pb.Start()
e := <-eventsChannel

There are many more methods supported and functionality available. We will be documenting this library more extensively in the future, but in the meantime, you can take a look at the libbpf_wrapper.go code to get an idea of what's possible, or look at the Tracee code as a consumer of this library, or just ask us by creating a new Discussion and we'd love to help.

Documentation

Index

• Constants
• func GetUnsafePointer(data interface{}) (unsafe.Pointer, error)
• type BPFLink
• type BPFMap
  • func (b *BPFMap) DeleteKey(key interface{}) error
  • func (b *BPFMap) GetMaxEntries() uint32
  • func (b *BPFMap) GetValue(key interface{}, valueSize int) ([]byte, error)
  • func (b *BPFMap) Iterator(keySize int) *BPFMapIterator
  • func (b *BPFMap) Pin(pinPath string) error
  • func (b *BPFMap) Resize(maxEntries uint32) error
  • func (b *BPFMap) SetPinPath(pinPath string) error
  • func (b *BPFMap) Unpin(pinPath string) error
  • func (b *BPFMap) Update(key, value interface{}) error
• type BPFMapIterator
  • func (it *BPFMapIterator) Err() error
  • func (it *BPFMapIterator) Key() []byte
  • func (it *BPFMapIterator) Next() bool
• type BPFProg
  • func (p *BPFProg) AttachKprobe(kp string) (*BPFLink, error)
  • func (p *BPFProg) AttachKprobeLegacy(kp string) (*BPFLink, error)
  • func (p *BPFProg) AttachKretprobe(kp string) (*BPFLink, error)
  • func (p *BPFProg) AttachKretprobeLegacy(kp string) (*BPFLink, error)
  • func (p *BPFProg) AttachLSM() (*BPFLink, error)
  • func (p *BPFProg) AttachPerfEvent(fd int) (*BPFLink, error)
  • func (p *BPFProg) AttachRawTracepoint(tpEvent string) (*BPFLink, error)
  • func (p *BPFProg) AttachTracepoint(tp string) (*BPFLink, error)
  • func (p *BPFProg) GetFd() C.int
  • func (p *BPFProg) GetType() uint32
  • func (p *BPFProg) SetAutoload(autoload bool) error
  • func (p *BPFProg) SetTracepoint() error
• type BPFProgType
• type LinkType
• type Module
  • func NewModuleFromBuffer(bpfObjBuff []byte, bpfObjName string) (*Module, error)
  • func NewModuleFromFile(bpfObjFile string) (*Module, error)
  • func (m *Module) BPFLoadObject() error
  • func (m *Module) Close()
  • func (m *Module) GetMap(mapName string) (*BPFMap, error)
  • func (m *Module) GetProgram(progName string) (*BPFProg, error)
  • func (m *Module) InitPerfBuf(mapName string, eventsChan chan []byte, lostChan chan uint64, pageCnt int) (*PerfBuffer, error)
  • func (m *Module) InitRingBuf(mapName string, eventsChan chan []byte) (*RingBuffer, error)
• type PerfBuffer
  • func (pb *PerfBuffer) Close()
  • func (pb *PerfBuffer) Start()
  • func (pb *PerfBuffer) Stop()
• type RingBuffer
  • func (rb *RingBuffer) Close()
  • func (rb *RingBuffer) Start()
  • func (rb *RingBuffer) Stop()

Constants

const (
	BPFProgTypeUnspec uint32 = iota
	BPFProgTypeSocketFilter
	BPFProgTypeKprobe
	BPFProgTypeSchedCls
	BPFProgTypeSchedAct
	BPFProgTypeTracepoint
	BPFProgTypeXdp
	BPFProgTypePerfEvent
	BPFProgTypeCgroupSkb
	BPFProgTypeCgroupSock
	BPFProgTypeLwtIn
	BPFProgTypeLwtOut
	BPFProgTypeLwtXmit
	BPFProgTypeSockOps
	BPFProgTypeSkSkb
	BPFProgTypeCgroupDevice
	BPFProgTypeSkMsg
	BPFProgTypeRawTracepoint
	BPFProgTypeCgroupSockAddr
	BPFProgTypeLwtSeg6Local
	BPFProgTypeLircMode2
	BPFProgTypeSkReuseport
	BPFProgTypeFlowDissector
	BPFProgTypeCgroupSysctl
	BPFProgTypeRawTracepointWritable
	BPFProgTypeCgroupSockopt
	BPFProgTypeTracing
	BPFProgTypeStructOps
	BPFProgTypeExt
	BPFProgTypeLsm
	BPFProgTypeSkLookup
)

Functions

func GetUnsafePointer

func GetUnsafePointer(data interface{}) (unsafe.Pointer, error)

Types

type BPFLink

type BPFLink struct {
	// contains filtered or unexported fields
}

type BPFMap

type BPFMap struct {
	// contains filtered or unexported fields
}

func (*BPFMap) DeleteKey

func (b *BPFMap) DeleteKey(key interface{}) error

func (*BPFMap) GetMaxEntries

func (b *BPFMap) GetMaxEntries() uint32

GetMaxEntries returns the map's capacity. Note: for ring buffer and perf buffer, maxEntries is the capacity in bytes.

func (*BPFMap) GetValue

func (b *BPFMap) GetValue(key interface{}, valueSize int) ([]byte, error)

func (*BPFMap) Iterator

func (b *BPFMap) Iterator(keySize int) *BPFMapIterator

func (*BPFMap) Pin

func (b *BPFMap) Pin(pinPath string) error

func (*BPFMap) Resize

func (b *BPFMap) Resize(maxEntries uint32) error

Resize changes the map's capacity to maxEntries. It should be called after the module was initialized but prior to it being loaded with BPFLoadObject. Note: for ring buffer and perf buffer, maxEntries is the capacity in bytes.

func (*BPFMap) SetPinPath

func (b *BPFMap) SetPinPath(pinPath string) error

func (*BPFMap) Unpin

func (b *BPFMap) Unpin(pinPath string) error

func (*BPFMap) Update

func (b *BPFMap) Update(key, value interface{}) error

type BPFMapIterator

type BPFMapIterator struct {
	// contains filtered or unexported fields
}

func (*BPFMapIterator) Err

func (it *BPFMapIterator) Err() error

Err returns the last error that ocurred while table.Iter or iter.Next

func (*BPFMapIterator) Key

func (it *BPFMapIterator) Key() []byte

Key returns the current key value of the iterator, if the most recent call to Next returned true. The slice is valid only until the next call to Next.

func (*BPFMapIterator) Next

func (it *BPFMapIterator) Next() bool

type BPFProg

type BPFProg struct {
	// contains filtered or unexported fields
}

func (*BPFProg) AttachKprobe

func (p *BPFProg) AttachKprobe(kp string) (*BPFLink, error)

this API should be used for kernels > 4.17

func (*BPFProg) AttachKprobeLegacy

func (p *BPFProg) AttachKprobeLegacy(kp string) (*BPFLink, error)

func (*BPFProg) AttachKretprobe

func (p *BPFProg) AttachKretprobe(kp string) (*BPFLink, error)

this API should be used for kernels > 4.17

func (*BPFProg) AttachKretprobeLegacy

func (p *BPFProg) AttachKretprobeLegacy(kp string) (*BPFLink, error)

func (*BPFProg) AttachLSM

func (p *BPFProg) AttachLSM() (*BPFLink, error)

func (*BPFProg) AttachPerfEvent

func (p *BPFProg) AttachPerfEvent(fd int) (*BPFLink, error)

func (*BPFProg) AttachRawTracepoint

func (p *BPFProg) AttachRawTracepoint(tpEvent string) (*BPFLink, error)

func (*BPFProg) AttachTracepoint

func (p *BPFProg) AttachTracepoint(tp string) (*BPFLink, error)

func (*BPFProg) GetFd

func (p *BPFProg) GetFd() C.int

func (*BPFProg) GetType

func (p *BPFProg) GetType() uint32

func (*BPFProg) SetAutoload

func (p *BPFProg) SetAutoload(autoload bool) error

func (*BPFProg) SetTracepoint

func (p *BPFProg) SetTracepoint() error

type BPFProgType

type BPFProgType uint32

BPFProgType is an enum as defined in https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/bpf.h

type LinkType

type LinkType int

const (
	Tracepoint LinkType = iota
	RawTracepoint
	Kprobe
	Kretprobe
	KprobeLegacy
	KretprobeLegacy
	LSM
	PerfEvent
)

type Module

type Module struct {
	// contains filtered or unexported fields
}

func NewModuleFromBuffer

func NewModuleFromBuffer(bpfObjBuff []byte, bpfObjName string) (*Module, error)

func NewModuleFromFile

func NewModuleFromFile(bpfObjFile string) (*Module, error)

func (*Module) BPFLoadObject

func (m *Module) BPFLoadObject() error

func (*Module) Close

func (m *Module) Close()

func (*Module) GetMap

func (m *Module) GetMap(mapName string) (*BPFMap, error)

func (*Module) GetProgram

func (m *Module) GetProgram(progName string) (*BPFProg, error)

func (*Module) InitPerfBuf

func (m *Module) InitPerfBuf(mapName string, eventsChan chan []byte, lostChan chan uint64, pageCnt int) (*PerfBuffer, error)

func (*Module) InitRingBuf

func (m *Module) InitRingBuf(mapName string, eventsChan chan []byte) (*RingBuffer, error)

type PerfBuffer

type PerfBuffer struct {
	// contains filtered or unexported fields
}

func (*PerfBuffer) Close

func (pb *PerfBuffer) Close()

func (*PerfBuffer) Start

func (pb *PerfBuffer) Start()

func (*PerfBuffer) Stop

func (pb *PerfBuffer) Stop()

type RingBuffer

type RingBuffer struct {
	// contains filtered or unexported fields
}

func (*RingBuffer) Close

func (rb *RingBuffer) Close()

func (*RingBuffer) Start

func (rb *RingBuffer) Start()

func (*RingBuffer) Stop

func (rb *RingBuffer) Stop()