From 94360d2c4f6b62b4ef849cca802b5db605cd36b7 Mon Sep 17 00:00:00 2001
From: Levente Kale <levente.kale@nokia.com>
Date: Thu, 30 Apr 2020 12:52:02 +0200
Subject: [PATCH 1/2] Disabling DAD on DANM allocated IPv6 addresses to avoid
 intermittent startup filures

---
 pkg/danmep/ep.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/pkg/danmep/ep.go b/pkg/danmep/ep.go
index f2def9a2..0fab1929 100644
--- a/pkg/danmep/ep.go
+++ b/pkg/danmep/ep.go
@@ -7,6 +7,7 @@ import (
   "os"
   "runtime"
   "strconv"
+  "syscall"
   "github.com/vishvananda/netlink"
   "github.com/containernetworking/plugins/pkg/ns"
   danmtypes "github.com/nokia/danm/crd/apis/danm/v1"
@@ -128,6 +129,10 @@ func addIpToLink(ip string, iface netlink.Link) error {
     return errors.New("cannot parse IP address because:" + err.Error())
   }
   ipAddr := &netlink.Addr{IPNet: &net.IPNet{IP: addr, Mask: pref.Mask}}
+  if addr.To4() == nil {
+    //Disable unnecessary DAD for IPv6 addresses managed by DANM
+    ipAddr.Flags = syscall.IFA_F_NODAD
+  }
   err = netlink.AddrAdd(iface, ipAddr)
   if err != nil {
     return errors.New("cannot add IP address to link because:" + err.Error())

From 1f1ba243d59d485cf5b5814b3d3f578d6e9be192 Mon Sep 17 00:00:00 2001
From: Levente Kale <levente.kale@nokia.com>
Date: Thu, 30 Apr 2020 15:19:11 +0200
Subject: [PATCH 2/2] Adding NODAD flag to V6 addresses provisioned by delegate
 CNIs.

We do this my "replacing" the provisioned IP address on the link with itself,
but with the right flag set.
---
 pkg/danmep/danmep.go |  8 ++++++--
 pkg/danmep/ep.go     | 13 +++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/pkg/danmep/danmep.go b/pkg/danmep/danmep.go
index d2d48435..ee177e04 100644
--- a/pkg/danmep/danmep.go
+++ b/pkg/danmep/danmep.go
@@ -183,7 +183,11 @@ func PostProcessInterface(ep *danmtypes.DanmEp, dnet *danmtypes.DanmNet) error {
   }
   err = setDanmEpSysctls(ep)
   if err != nil {
-    return errors.New("failed to set kernel configs for interface" + ep.Spec.Iface.Name + " beause:" + err.Error())
+    return errors.New("failed to set kernel configs for interface" + ep.Spec.Iface.Name + " because:" + err.Error())
+  }
+  err = disableDadOnIface(ep, isVfAttachedToDpdkDriver)
+  if err != nil {
+    return errors.New("failed to disable DAD for address" + ep.Spec.Iface.AddressIPv6 + " because:" + err.Error())
   }
   return addIpRoutes(ep,dnet)
 }
@@ -382,7 +386,7 @@ func getVfMac(pciId string) net.HardwareAddr {
   pfLink, err := netlink.LinkByName(pfName)
   if err != nil {
     return net.HardwareAddr{}
-  } 
+  }
   if pfLink.Attrs() != nil && len(pfLink.Attrs().Vfs) >= vfId {
     return pfLink.Attrs().Vfs[vfId].Mac
   }
diff --git a/pkg/danmep/ep.go b/pkg/danmep/ep.go
index 0fab1929..05ff449a 100644
--- a/pkg/danmep/ep.go
+++ b/pkg/danmep/ep.go
@@ -324,4 +324,17 @@ func createDummyInterface(ep *danmtypes.DanmEp, dnet *danmtypes.DanmNet) error {
     return errors.New("cannot find freshly created dummy interface because:" + err.Error())
   }
   return configureLink(iface, ep)
+}
+
+func disableDadOnIface(ep *danmtypes.DanmEp, isDummyIface bool) error {
+  if isDummyIface || ep.Spec.NetworkType == "ipvlan" || ep.Spec.Iface.AddressIPv6 == "" || ep.Spec.Iface.AddressIPv6 == ipam.NoneAllocType {
+    return nil
+  }
+  link, err := netlink.LinkByName(ep.Spec.Iface.Name)
+  if err != nil {
+    return errors.New("cannot find interface to disable DAD on its V6 address because:" + err.Error())
+  }
+  addr, pref, _ := net.ParseCIDR(ep.Spec.Iface.AddressIPv6)
+  dadlessAddress := &netlink.Addr{IPNet: &net.IPNet{IP: addr, Mask: pref.Mask}, Flags: syscall.IFA_F_NODAD,}
+  return netlink.AddrReplace(link, dadlessAddress)
 }
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