1 files changed, 215 insertions, 0 deletions
diff --git a/usage/main.go b/usage/main.go
new file mode 100644
index 0000000..8015aa0
--- /dev/null
+++ b/usage/main.go
@@ -0,0 +1,215 @@
+package usage
+
+import (
+	"context"
+	"errors"
+	"log"
+	"net"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/cilium/ebpf"
+	"github.com/cilium/ebpf/link"
+	"github.com/jackc/pgx/v5/pgtype"
+	"sinanmohd.com/redq/db"
+)
+
+type UsageStat struct {
+	lastSeen         time.Time
+	lastDbPush       time.Time
+	BandwidthIngress uint64
+	BandwidthEgress  uint64
+	Ingress          uint64
+	Egress           uint64
+}
+
+type UsageMap map[uint64]UsageStat
+type Usage struct {
+	Data UsageMap
+	Mutex sync.Mutex
+}
+
+func (u *Usage) Run(iface *net.Interface, queries *db.Queries, ctxDb context.Context) {
+	objs := bpfObjects{}
+	if err := loadBpfObjects(&objs, nil); err != nil {
+		log.Fatalf("loading objects: %s", err)
+	}
+	defer objs.Close()
+
+	ingressLink, err := link.AttachTCX(link.TCXOptions{
+		Interface: iface.Index,
+		Program:   objs.IngressFunc,
+		Attach:    ebpf.AttachTCXIngress,
+	})
+	if err != nil {
+		log.Fatalf("could not attach TCx program: %s", err)
+	}
+	defer ingressLink.Close()
+
+	egressLink, err := link.AttachTCX(link.TCXOptions{
+		Interface: iface.Index,
+		Program:   objs.EgressFunc,
+		Attach:    ebpf.AttachTCXEgress,
+	})
+	if err != nil {
+		log.Fatalf("could not attach TCx program: %s", err)
+	}
+	defer egressLink.Close()
+
+	bpfTicker := time.NewTicker(time.Second)
+	defer bpfTicker.Stop()
+	dbTicker := time.NewTicker(time.Minute)
+	defer dbTicker.Stop()
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, os.Interrupt, os.Kill, syscall.SIGTERM)
+
+	for {
+		select {
+		case <-bpfTicker.C:
+			err := u.update(objs.IngressIp4UsageMap, objs.EgressIp4UsageMap)
+			if err != nil {
+				log.Printf("updating usageMap: %s", err)
+			}
+		case <-sigs:
+			err := u.updateDb(queries, ctxDb, false)
+			if err != nil {
+				log.Printf("updating Database: %s", err)
+			}
+			os.Exit(0)
+		case <-dbTicker.C:
+			err := u.updateDb(queries, ctxDb, true)
+			if err != nil {
+				log.Printf("updating Database: %s", err)
+			}
+		}
+	}
+}
+
+func (usageStat *UsageStat) expired(timeStart *time.Time) bool {
+	timeDiff := timeStart.Sub(usageStat.lastSeen)
+	if timeDiff > time.Minute {
+		return true
+	}
+
+	timeDiff = timeStart.Sub(usageStat.lastDbPush)
+	if timeDiff > time.Hour {
+		return true
+	}
+
+	return false
+}
+
+func (u *Usage) updateDb(queries *db.Queries, ctxDb context.Context, ifExpired bool) error {
+	timeStart := time.Now()
+
+	u.Mutex.Lock()
+	for key, value := range u.Data {
+		if ifExpired && !value.expired(&timeStart) {
+			continue
+		}
+
+		err := queries.EnterUsage(ctxDb, db.EnterUsageParams{
+			Hardwareaddr: int64(key),
+			Starttime: pgtype.Timestamp{
+				Time:  value.lastDbPush,
+				Valid: true,
+			},
+			Stoptime: pgtype.Timestamp{
+				Time:  value.lastSeen,
+				Valid: true,
+			},
+			Egress:  int64(value.Egress),
+			Ingress: int64(value.Ingress),
+		})
+		if err != nil {
+			return err
+		}
+
+		delete(u.Data, key)
+	}
+	u.Mutex.Unlock()
+
+	return nil
+}
+
+func (u *Usage) update(ingress *ebpf.Map, egress *ebpf.Map) error {
+	timeStart := time.Now()
+	batchKeys := make([]uint64, 4096)
+	batchValues := make([]uint64, 4096)
+	var key uint64
+
+	cursor := ebpf.MapBatchCursor{}
+	for {
+		_, err := ingress.BatchLookupAndDelete(&cursor, batchKeys, batchValues, nil)
+		for i := range batchKeys {
+			/* TODO: maybe BatchLookupAndDelete is not the best idea with mostly empty map */
+			if batchValues[i] == 0 {
+				continue
+			}
+
+			key = batchKeys[i]
+			u.Mutex.Lock()
+			usage, ok := u.Data[key]
+			if ok {
+				usage.BandwidthIngress = batchValues[i] - usage.Ingress
+				usage.Ingress += batchValues[i]
+				usage.lastSeen = timeStart
+				u.Data[key] = usage
+			} else {
+				u.Data[key] = UsageStat{
+					BandwidthIngress: batchValues[i],
+					Ingress:          batchValues[i],
+					lastDbPush:       timeStart,
+					lastSeen:         timeStart,
+				}
+			}
+			u.Mutex.Unlock()
+		}
+
+		if errors.Is(err, ebpf.ErrKeyNotExist) {
+			break
+		} else if err != nil {
+			return err
+		}
+	}
+
+	cursor = ebpf.MapBatchCursor{}
+	for {
+		_, err := egress.BatchLookupAndDelete(&cursor, batchKeys, batchValues, nil)
+		for i := range batchKeys {
+			/* TODO: maybe BatchLookupAndDelete is not the best idea with mostly empty map */
+			if batchValues[i] == 0 {
+				continue
+			}
+
+			key = batchKeys[i]
+			u.Mutex.Lock()
+			usage, ok := u.Data[key]
+			if ok {
+				usage.BandwidthEgress = batchValues[i] - usage.Egress
+				usage.Egress += batchValues[i]
+				usage.lastSeen = timeStart
+				u.Data[key] = usage
+			} else {
+				u.Data[key] = UsageStat{
+					BandwidthEgress: batchValues[i],
+					Egress:          batchValues[i],
+					lastDbPush:      timeStart,
+					lastSeen:        timeStart,
+				}
+			}
+			u.Mutex.Unlock()
+		}
+
+		if errors.Is(err, ebpf.ErrKeyNotExist) {
+			break
+		} else if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}