Example: Add netem example with a 100ms delay

example_netem_test.go

@@ -7,6 +7,7 @@ import (
  "fmt"
  "net"
  "os"
+ "time"
 
  "github.com/florianl/go-tc"
  "github.com/florianl/go-tc/core"
@@ -92,3 +93,87 @@ func ExampleNetem() {
  fmt.Printf("%20s\t%s\n", iface.Name, qdisc.Kind)
  }
 }
+
+func ExampleNetemDelay() {
+ tcIface := "ExampleNetemDelay"
+
+ rtnl, err := setupDummyInterface(tcIface)
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "could not setup dummy interface: %v\n", err)
+ return
+ }
+ defer rtnl.Close()
+
+ devID, err := net.InterfaceByName(tcIface)
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "could not get interface ID: %v\n", err)
+ return
+ }
+ defer func(devID uint32, rtnl *rtnetlink.Conn) {
+ if err := rtnl.Link.Delete(devID); err != nil {
+ fmt.Fprintf(os.Stderr, "could not delete interface: %v\n", err)
+ }
+ }(uint32(devID.Index), rtnl)
+
+ tcnl, err := tc.Open(&tc.Config{})
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "could not open rtnetlink socket: %v\n", err)
+ return
+ }
+ defer func() {
+ if err := tcnl.Close(); err != nil {
+ fmt.Fprintf(os.Stderr, "could not close rtnetlink socket: %v\n", err)
+ }
+ }()
+
+ tcTime, err := core.Duration2TcTime(100 * time.Millisecond)
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "could not convert duration to TC time: %v\n", err)
+ return
+ }
+ ticks := core.Time2Tick(tcTime)
+
+ qdisc := tc.Object{
+ tc.Msg{
+ Family: unix.AF_UNSPEC,
+ Ifindex: uint32(devID.Index),
+ Handle: core.BuildHandle(0x1, 0x0),
+ Parent: tc.HandleRoot,
+ Info: 0,
+ },
+ tc.Attribute{
+ Kind: "netem",
+ // tc qdisc add dev tcDev root netem delay 100ms
+ Netem: &tc.Netem{
+ Qopt: tc.NetemQopt{
+ Latency: ticks,
+ Limit: 1000,
+ },
+ },
+ },
+ }
+
+ if err := tcnl.Qdisc().Replace(&qdisc); err != nil {
+ fmt.Fprintf(os.Stderr, "could not assign qdisc netem to lo: %v\n", err)
+ return
+ }
+ defer func() {
+ if err := tcnl.Qdisc().Delete(&qdisc); err != nil {
+ fmt.Fprintf(os.Stderr, "could not delete netem qdisc of lo: %v\n", err)
+ return
+ }
+ }()
+ qdiscs, err := tcnl.Qdisc().Get()
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "could not get all qdiscs: %v\n", err)
+ }
+
+ for _, qdisc := range qdiscs {
+ iface, err := net.InterfaceByIndex(int(qdisc.Ifindex))
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "could not get interface from id %d: %v", qdisc.Ifindex, err)
+ return
+ }
+ fmt.Printf("%20s\t%s\n", iface.Name, qdisc.Kind)
+ }
+}