inspektor-gadget

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// Copyright 2019-2024 The Inspektor Gadget authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//     http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:build !withoutebpf
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package tracer
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import (
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	"context"
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	"errors"
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	"fmt"
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	"unsafe"
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	gadgetcontext "github.com/inspektor-gadget/inspektor-gadget/pkg/gadget-context"
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	"github.com/inspektor-gadget/inspektor-gadget/pkg/gadgets"
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	"github.com/inspektor-gadget/inspektor-gadget/pkg/gadgets/trace/sni/types"
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	"github.com/inspektor-gadget/inspektor-gadget/pkg/networktracer"
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	eventtypes "github.com/inspektor-gadget/inspektor-gadget/pkg/types"
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)
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//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -target bpfel -cc clang -cflags ${CFLAGS} -type event_t snisnoop ./bpf/snisnoop.c -- $CLANG_OS_FLAGS -I./bpf/
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const (
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	TLSMaxServerNameLen = len(snisnoopEventT{}.Name)
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)
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type Tracer struct {
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	*networktracer.Tracer[types.Event]
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	ctx    context.Context
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	cancel context.CancelFunc
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}
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func NewTracer() (*Tracer, error) {
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	t := &Tracer{}
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	if err := t.install(); err != nil {
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		t.Close()
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		return nil, fmt.Errorf("installing tracer: %w", err)
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	}
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	if err := t.run(); err != nil {
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		t.Close()
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		return nil, fmt.Errorf("running tracer: %w", err)
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	}
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	return t, nil
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}
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func parseSNIEvent(sample []byte, netns uint64) (*types.Event, error) {
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	bpfEvent := (*snisnoopEventT)(unsafe.Pointer(&sample[0]))
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	if len(sample) < int(unsafe.Sizeof(*bpfEvent)) {
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		return nil, errors.New("invalid sample size")
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	}
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	timestamp := gadgets.WallTimeFromBootTime(bpfEvent.Timestamp)
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	name := gadgets.FromCString(bpfEvent.Name[:])
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	if len(name) == 0 {
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		return nil, nil
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	}
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	event := types.Event{
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		Event: eventtypes.Event{
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			Type:      eventtypes.NORMAL,
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			Timestamp: timestamp,
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		},
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		Pid:           bpfEvent.Pid,
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		Tid:           bpfEvent.Tid,
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		Uid:           bpfEvent.Uid,
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		Gid:           bpfEvent.Gid,
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		WithMountNsID: eventtypes.WithMountNsID{MountNsID: bpfEvent.MountNsId},
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		WithNetNsID:   eventtypes.WithNetNsID{NetNsID: netns},
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		Comm:          gadgets.FromCString(bpfEvent.Task[:]),
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		Name: name,
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	}
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	return &event, nil
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}
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// --- Registry changes
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func (g *GadgetDesc) NewInstance() (gadgets.Gadget, error) {
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	return &Tracer{}, nil
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}
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func (t *Tracer) Init(gadgetCtx gadgets.GadgetContext) error {
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	if err := t.install(); err != nil {
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		t.Close()
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		return fmt.Errorf("installing tracer: %w", err)
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	}
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	t.ctx, t.cancel = gadgetcontext.WithTimeoutOrCancel(gadgetCtx.Context(), gadgetCtx.Timeout())
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	return nil
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}
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func (t *Tracer) install() error {
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	networkTracer, err := networktracer.NewTracer[types.Event]()
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	if err != nil {
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		return fmt.Errorf("creating network tracer: %w", err)
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	}
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	t.Tracer = networkTracer
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	return nil
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}
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func (t *Tracer) run() error {
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	spec, err := loadSnisnoop()
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	if err != nil {
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		return fmt.Errorf("loading asset: %w", err)
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	}
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	err = t.Tracer.Run(spec, types.Base, parseSNIEvent)
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	if err != nil {
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		return fmt.Errorf("setting network tracer spec: %w", err)
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	}
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	return nil
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}
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func (t *Tracer) Run(gadgetCtx gadgets.GadgetContext) error {
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	if err := t.run(); err != nil {
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		return nil
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	}
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	<-t.ctx.Done()
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	return nil
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}
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func (t *Tracer) Close() {
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	if t.cancel != nil {
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		t.cancel()
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	}
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	if t.Tracer != nil {
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		t.Tracer.Close()
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	}
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}
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