Add ebpf

Author: halfrost

ebpf/ebpf-kernel/bpf_bpfeb.go

@@ -0,0 +1,144 @@
+//go:build linux
+// +build linux
+
+package main
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"log"
+	"net"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+	
+	"github.com/cilium/ebpf"
+	"github.com/cilium/ebpf/link"
+	"github.com/cilium/ebpf/ringbuf"
+	"github.com/cilium/ebpf/rlimit"
+)
+
+// $BPF_CLANG and $BPF_CFLAGS are set by the Makefile.
+//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc $BPF_CLANG -cflags $BPF_CFLAGS -type event bpf fentry.c -- -I../headers
+
+func main() {
+	if len(os.Args) < 2 {
+		log.Fatalf("Please specify a network interface")
+	}
+
+	ifaceName := os.Args[1]
+	iface, err := net.InterfaceByName(ifaceName)
+	if err != nil {
+		log.Fatalf("lookup network iface %q: %s", ifaceName, err)
+	}
+
+	objs := bpfObjects{}
+	if err := loadBpfObjects(&objs, nil); err != nil {
+		log.Fatalf("loading objects: %s", err)
+	}
+	defer objs.Close()
+
+	l, err := link.AttachXDP(link.XDPOptions{
+		Program:   objs.XdpProgFunc,
+		Interface: iface.Index,
+	})
+	if err != nil {
+		log.Fatalf("could not attach XDP program: %s", err)
+	}
+	defer l.Close()
+
+	log.Printf("Attached XDP program to iface %q (index %d)", iface.Name, iface.Index)
+
+	ticker := time.NewTicker(1 * time.Second)
+	defer ticker.Stop()
+	for range ticker.C {
+		s, err := formatMapContents(objs.XdpStatsMap)
+		if err != nil {
+			log.Printf("Error reading map: %s", err)
+			continue
+		}
+		log.Printf("Map contents:\n%s", s)
+	}
+}
+
+func intToIP(ipNum uint32) net.IP {
+	ip := make(net.IP, 4)
+	binary.BigEndian.PutUint32(ip, ipNum)
+	return ip
+}
+
+func saveDataToMap(desPort, srcAddr, port string) {
+		// Allow the current process to lock memory for eBPF resources.
+		if err := rlimit.RemoveMemlock(); err != nil {
+			log.Fatal(err)
+		}
+	
+		outerMapSpec := ebpf.MapSpec{
+			Name:       "outer_map",
+			Type:       ebpf.ArrayOfMaps,
+			KeySize:    10000,
+			ValueSize:  10000,
+			MaxEntries: 10000,
+			Contents:   make([]ebpf.MapKV, 5),
+			InnerMap: &ebpf.MapSpec{
+				Name:      "inner_map",
+				Type:      ebpf.Array,
+				KeySize:   100,
+				ValueSize: 100,
+				Flags: unix.BPF_F_INNER_MAP,
+				MaxEntries: 1,
+			},
+		}
+	
+		innerMapSpec := outerMapSpec.InnerMap.Copy()
+		innerMapSpec.MaxEntries = 1000
+		innerMapSpec.Contents = make([]ebpf.MapKV, innerMapSpec.MaxEntries)
+		innerMapSpec = append(innerMapSpec, ebpf.MapKV{Key: desPort, Value: srcAddr+port})
+		innerMap, err := ebpf.NewMap(innerMapSpec)
+		if err != nil {
+			log.Fatalf("inner_map: %v", err)
+		}
+		defer innerMap.Close()
+		outerMapSpec.Contents = append(outerMapSpec.Contents, ebpf.MapKV{Key: i, Value: innerMap})
+}
+
+func readMap(outerMapSpec ebpf.MapSpec) {
+	outerMap, err := ebpf.NewMap(&outerMapSpec)
+	if err != nil {
+		log.Fatalf("outer_map: %v", err)
+	}
+	defer outerMap.Close()
+
+	mapIter := outerMap.Iterate()
+	var outerMapKey uint32
+	var innerMapID ebpf.MapID
+	for mapIter.Next(&outerMapKey, &innerMapID) {
+		innerMap, err := ebpf.NewMapFromID(innerMapID)
+		if err != nil {
+			log.Fatal(err)
+		}
+		innerMapInfo, err := innerMap.Info()
+		if err != nil {
+			log.Fatal(err)
+		}
+		log.Printf("outerMapKey %d, innerMap.Info: %+v", outerMapKey, innerMapInfo.)
+	}
+}
+
+func formatMapContents(m *ebpf.Map) (string, error) {
+	var (
+		sb  strings.Builder
+		key []byte
+		val uint32
+	)
+	iter := m.Iterate()
+	for iter.Next(&key, &val) {
+		sourceIP := net.IP(key) // IPv4 source address in network byte order.
+		packetCount := val
+		sb.WriteString(fmt.Sprintf("\t%s => %d\n", sourceIP, packetCount))
+	}
+	return sb.String(), iter.Err()
+}