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main.go
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main.go
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package main
import "C"
import (
"encoding/binary"
"os"
"os/exec"
"syscall"
"fmt"
bpf "github.com/aquasecurity/libbpfgo"
)
func main() {
bpfModule, err := bpf.NewModuleFromFile("main.bpf.o")
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(-1)
}
defer bpfModule.Close()
err = bpfModule.BPFLoadObject()
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(-1)
}
hook := bpfModule.TcHookInit()
defer func() {
if err := hook.Destroy(); err != nil {
fmt.Fprintln(os.Stderr, err)
}
}()
err = hook.SetInterfaceByName("lo")
if err != nil {
fmt.Fprintln(os.Stderr, "failed to set tc hook on interface lo: %v", err)
os.Exit(-1)
}
hook.SetAttachPoint(bpf.BPFTcEgress)
err = hook.Create()
if err != nil {
if errno, ok := err.(syscall.Errno); ok && errno != syscall.EEXIST {
fmt.Fprintln(os.Stderr, "tc hook create: %v", err)
}
}
tcProg, err := bpfModule.GetProgram("target")
if tcProg == nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(-1)
}
var tcOpts bpf.TcOpts
tcOpts.ProgFd = int(tcProg.GetFd())
tcOpts.Flags = bpf.BpfTcFReplace
tcOpts.Handle = 1
err = hook.Attach(&tcOpts)
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(-1)
}
// test for query
tcOpts.Flags = 0
tcOpts.ProgFd = 0
tcOpts.ProgId = 0
err = hook.Query(&tcOpts)
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(-1)
}
if tcOpts.Handle != 1 {
fmt.Fprintln(os.Stderr, "query info error, handle:%d", tcOpts.Handle)
os.Exit(-1)
}
// test for detach
defer func() {
tcOpts.Flags = 0
tcOpts.ProgFd = 0
tcOpts.ProgId = 0
err = hook.Detach(&tcOpts)
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(-1)
}
}()
eventsChannel := make(chan []byte)
rb, err := bpfModule.InitRingBuf("events", eventsChannel)
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(-1)
}
rb.Poll(300)
numberOfEventsReceived := 0
go func() {
_, err := exec.Command("ping", "localhost", "-c 10").Output()
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(-1)
}
}()
recvLoop:
for {
b := <-eventsChannel
if binary.LittleEndian.Uint32(b) != 2021 {
fmt.Fprintf(os.Stderr, "invalid data retrieved\n")
os.Exit(-1)
}
numberOfEventsReceived++
if numberOfEventsReceived > 5 {
break recvLoop
}
}
rb.Stop()
rb.Close()
}