libbpfgo

package module
v0.2.1-libbpf-0.4.0 Latest Latest
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 Go to latest Published: Sep 3, 2021 License: Apache-2.0 Imports: 9 Imported by: 120

README

libbpfgo

libbpfgo is a Go library for Linux's eBPF project. It was created for Tracee, our open source Runtime Security, and eBPF tracing tool, written in Go. If you are interested in eBPF and its applications, check out Tracee at Github: https://github.com/aquasecurity/tracee.

libbpfgo is built around libbpf - the standard library for interacting with eBPF programs from userspace - which is a C library maintained in Linux upstream. We have created libbpfgo as a thin Go wrapper around the libbpf project.

Installing

libbpfgo uses 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 libbpf as a shared object in the system. Libbpf may already be packaged for your distribution and, 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.

Building

Currently you will find the following GNU Makefile rules:

Makefile Rule Description
all builds libbpfgo (dynamic)
clean cleans entire tree
selftest builds all selftests (static)
selftest-run runs all selftests (static)
  • libbpf dynamically linked (libbpf from OS)
Makefile Rule Description
libbpfgo-dynamic builds dynamic libbpfgo (libbpf)
libbpfgo-dynamic-test 'go test' with dynamic libbpfgo
selftest-dynamic build tests with dynamic libbpfgo
selftest-dynamic-run run tests using dynamic libbpfgo
  • statically compiled (libbpf submodule)
Makefile Rule Description
libbpfgo-static builds static libbpfgo (libbpf)
libbpfgo-static-test 'go test' with static libbpfgo
selftest-static build tests with static libbpfgo
selftest-static-run run tests using static libbpfgo
  • examples
$ make libbpfgo-static => libbpfgo statically linked with libbpf
$ make -C selftest/perfbuffers => single selftest build (static libbpf)
$ make -C selftest/perfbuffers run-dynamic => single selftest run (dynamic libbpf)
$ make selftest-static-run => will build & run all static selftests

Note 01: dynamic builds need your OS to have a recent enough libbpf package (and its headers) installed. Sometimes, recent features might require the use of backported OS packages in order for your OS to contain latest libbpf features (sometimes required by libbpfgo). Note 02: static builds need git submodule init first. Make sure to sync the libbpf git submodule before trying to statically compile or test the libbpfgo repository.

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 RingBuffer struct and it's associated objects.

Example

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

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

// ring buffer
rb, _ := bpfModule.InitRingBuffer("events", eventsChannel, buffSize)
rb.Start()
e := <-eventsChannel

Releases

libbpfgo does not yet have a regular schedule for cutting releases. There has not yet been a major release but API backwards compatibility will be maintained for all releases with the same major release number. Milestones are created when preparing for release.

  • Major releases are cut when backwards compatibility is broken or major milestones are completed, such as reaching parity with libbpf's API.
  • Minor releases are cut to incorporate new support for libbpf APIs.
  • Patch releases are cut to incorporate important individual or groupings of bug fixes.
  • libbpf support numbering indicates the minimum required libbpf version that must be linked in order to ensure libbpfgo compatibility. For example, v0.2.1-libbpf_0.4.0 means that version 0.2.1 of libbpfgo requires v0.4.0 or newer of libbpf.

Note: some distributions might have local changes to their libbpf package and their version might include backports and/or fixes differently than upstream versions. In those cases we recommend that libbpfgo is used statically compiled.

Learn more

Please check our github milestones for an idea of the project roadmap. The general goal is to fully implement/expose libbpf's API in Go as seamlessly as possible.

Documentation

Index

Constants

View Source 
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
)

Variables

This section is empty.

Functions

func GetUnsafePointer 

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

Types 

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

func (*BPFLink) Destroy 

func (l *BPFLink) Destroy() error

type BPFMap 

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

func (*BPFMap) DeleteKey 

func (b *BPFMap) DeleteKey(key unsafe.Pointer) error

DeleteKey takes a pointer to the key which is stored in the map. It removes the key and associated value from the BPFMap. All basic types, and structs are supported as keys.

NOTE: Slices and arrays are also supported but special care should be taken as to take a reference to the first element in the slice or array instead of the slice/array itself, as to avoid undefined behavior.

func (*BPFMap) GetFd 

func (b *BPFMap) GetFd() int

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) GetModule 

func (b *BPFMap) GetModule() *Module

func (*BPFMap) GetName 

func (b *BPFMap) GetName() string

func (*BPFMap) GetPinPath 

func (b *BPFMap) GetPinPath() string

func (*BPFMap) GetValue 

func (b *BPFMap) GetValue(key unsafe.Pointer) ([]byte, error)

GetValue takes a pointer to the key which is stored in the map. It returns the associated value as a slice of bytes. All basic types, and structs are supported as keys.

NOTE: Slices and arrays are also supported but special care should be taken as to take a reference to the first element in the slice or array instead of the slice/array itself, as to avoid undefined behavior.

func (*BPFMap) IsPinned 

func (b *BPFMap) IsPinned() bool

func (*BPFMap) Iterator 

func (b *BPFMap) Iterator() *BPFMapIterator

func (*BPFMap) KeySize 

func (b *BPFMap) KeySize() int

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 unsafe.Pointer) error

Update takes a pointer to a key and a value to associate it with in the BPFMap. The unsafe.Pointer should be taken on a reference to the underlying datatype. All basic types, and structs are supported

NOTE: Slices and arrays are supported but references should be passed to the first element in the slice or array.

For example: 

key := 1
value := []byte{'a', 'b', 'c'}
keyPtr := unsafe.Pointer(&key)
valuePtr := unsafe.Pointer(&value[0])
bpfmap.Update(keyPtr, valuePtr)

func (*BPFMap) ValueSize 

func (b *BPFMap) ValueSize() int

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) AttachURetprobe 

func (p *BPFProg) AttachURetprobe(pid int, path string, offset uint32) (*BPFLink, error)

AttachURetprobe attaches the BPFProgram to exit of the symbol in the library or binary at 'path' which can be relative or absolute. A pid can be provided to attach to, or -1 can be specified to attach to all processes

func (*BPFProg) AttachUprobe 

func (p *BPFProg) AttachUprobe(pid int, path string, offset uint32) (*BPFLink, error)

AttachUprobe attaches the BPFProgram to entry of the symbol in the library or binary at 'path' which can be relative or absolute. A pid can be provided to attach to, or -1 can be specified to attach to all processes

func (*BPFProg) GetFd 

func (p *BPFProg) GetFd() int

func (*BPFProg) GetModule 

func (p *BPFProg) GetModule() *Module

func (*BPFProg) GetName 

func (p *BPFProg) GetName() string

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
	Uprobe
	Uretprobe
)

type Module 

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

func NewModuleFromBuffer 

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

func NewModuleFromBufferArgs 

func NewModuleFromBufferArgs(args NewModuleArgs) (*Module, error)

func NewModuleFromFile 

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

func NewModuleFromFileArgs 

func NewModuleFromFileArgs(args NewModuleArgs) (*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)

func (*Module) TcHookInit 

func (m *Module) TcHookInit() *TcHook

type NewModuleArgs 

type NewModuleArgs struct {
	KConfigFilePath string
	BTFObjPath      string
	BPFObjName      string
	BPFObjPath      string
	BPFObjBuff      []byte
}

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()

type TcAttachPoint 

type TcAttachPoint uint32
const (
	BPFTcIngress       TcAttachPoint = C.BPF_TC_INGRESS
	BPFTcEgress        TcAttachPoint = C.BPF_TC_EGRESS
	BPFTcIngressEgress TcAttachPoint = C.BPF_TC_INGRESS | C.BPF_TC_EGRESS
	BPFTcCustom        TcAttachPoint = C.BPF_TC_CUSTOM
)

type TcFlags 

type TcFlags uint32
const (
	BpfTcFReplace TcFlags = C.BPF_TC_F_REPLACE
)

type TcHook 

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

func (*TcHook) Attach 

func (hook *TcHook) Attach(tcOpts *TcOpts) error

func (*TcHook) Create 

func (hook *TcHook) Create() error

func (*TcHook) Destroy 

func (hook *TcHook) Destroy() error

func (*TcHook) Detach 

func (hook *TcHook) Detach(tcOpts *TcOpts) error

func (*TcHook) GetInterfaceIndex 

func (hook *TcHook) GetInterfaceIndex() int

func (*TcHook) Query 

func (hook *TcHook) Query(tcOpts *TcOpts) error

func (*TcHook) SetAttachPoint 

func (hook *TcHook) SetAttachPoint(attachPoint TcAttachPoint)

func (*TcHook) SetInterfaceByIndex 

func (hook *TcHook) SetInterfaceByIndex(ifaceIdx int)

func (*TcHook) SetInterfaceByName 

func (hook *TcHook) SetInterfaceByName(ifaceName string) error

func (*TcHook) SetParent 

func (hook *TcHook) SetParent(a int, b int)

type TcOpts 

type TcOpts struct {
	ProgFd   int
	Flags    TcFlags
	ProgId   uint
	Handle   uint
	Priority uint
}

Source Files

View all Source files

Directories

Path Synopsis
selftest
attachgenericfd Module
global-variable Module
iter Module
iterators Module
log-callbacks Module
map-pin-info Module
map-update Module
module-attach-detach Module
perfbuffers Module
tracing Module
tracing-by-offset Module
uprobe Module

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