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//go:build linux
// getting_started_main {
package main
import (
"log"
"net"
"os"
"os/signal"
"time"
"github.com/cilium/ebpf/link"
"github.com/cilium/ebpf/rlimit"
)
func main() {
// Remove resource limits for kernels <5.11.
if err := rlimit.RemoveMemlock(); err != nil { // (1)!
log.Fatal("Removing memlock:", err)
}
// Load the compiled eBPF ELF and load it into the kernel.
var objs counterObjects // (2)!
if err := loadCounterObjects(&objs, nil); err != nil {
log.Fatal("Loading eBPF objects:", err)
}
defer objs.Close() // (3)!
ifname := "eth0" // Change this to an interface on your machine.
iface, err := net.InterfaceByName(ifname)
if err != nil {
log.Fatalf("Getting interface %s: %s", ifname, err)
}
// Attach count_packets to the network interface.
link, err := link.AttachXDP(link.XDPOptions{ // (4)!
Program: objs.CountPackets,
Interface: iface.Index,
})
if err != nil {
log.Fatal("Attaching XDP:", err)
}
defer link.Close() // (5)!
log.Printf("Counting incoming packets on %s..", ifname)
// Periodically fetch the packet counter from PktCount,
// exit the program when interrupted.
tick := time.Tick(time.Second)
stop := make(chan os.Signal, 5)
signal.Notify(stop, os.Interrupt)
for {
select {
case <-tick:
var count uint64
err := objs.PktCount.Lookup(uint32(0), &count) // (6)!
if err != nil {
log.Fatal("Map lookup:", err)
}
log.Printf("Received %d packets", count)
case <-stop:
log.Print("Received signal, exiting..")
return
}
}
}
// }
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