From 8914c8cd076716a82021058f52798fd0da3cbd54 Mon Sep 17 00:00:00 2001
From: zhangzujian <zhangzujian.7@gmail.com>
Date: Mon, 26 Aug 2024 05:59:45 +0000
Subject: [PATCH] cni: always enable ipv6

Signed-off-by: zhangzujian <zhangzujian.7@gmail.com>
---
 cmd/cni/cni.go            |  4 ++++
 cmd/cni/sysctl.go         | 32 ++++++++++++++++++++++++++++++++
 cmd/cni/sysctl_windows.go |  6 ++++++
 3 files changed, 42 insertions(+)
 create mode 100644 cmd/cni/sysctl.go
 create mode 100644 cmd/cni/sysctl_windows.go

diff --git a/cmd/cni/cni.go b/cmd/cni/cni.go
index 48b540c5f9f..65ca2fe1e92 100644
--- a/cmd/cni/cni.go
+++ b/cmd/cni/cni.go
@@ -50,6 +50,10 @@ func cmdAdd(args *skel.CmdArgs) error {
 		netConf.Provider = util.OvnProvider
 	}
 
+	if err = sysctlEnableIPv6(args.Netns); err != nil {
+		return err
+	}
+
 	client := request.NewCniServerClient(netConf.ServerSocket)
 	response, err := client.Add(request.CniRequest{
 		CniType:                    netConf.Type,
diff --git a/cmd/cni/sysctl.go b/cmd/cni/sysctl.go
new file mode 100644
index 00000000000..d98fc596fa5
--- /dev/null
+++ b/cmd/cni/sysctl.go
@@ -0,0 +1,32 @@
+//go:build !windows
+// +build !windows
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/containernetworking/plugins/pkg/ns"
+	"github.com/containernetworking/plugins/pkg/utils/sysctl"
+)
+
+// For docker version >=17.x the "none" network will disable ipv6 by default.
+// We have to enable ipv6 here to add v6 address and gateway.
+// See https://github.com/containernetworking/cni/issues/531
+func sysctlEnableIPv6(nsPath string) error {
+	return ns.WithNetNSPath(nsPath, func(_ ns.NetNS) error {
+		for _, conf := range [...]string{"all", "default"} {
+			name := fmt.Sprintf("net.ipv6.conf.%s.disable_ipv6", conf)
+			value, err := sysctl.Sysctl(name)
+			if err != nil {
+				return fmt.Errorf("failed to get sysctl variable %s: %w", name, err)
+			}
+			if value != "0" {
+				if _, err = sysctl.Sysctl(name, "0"); err != nil {
+					return fmt.Errorf("failed to set sysctl variable %s to 0: %w", name, err)
+				}
+			}
+		}
+		return nil
+	})
+}
diff --git a/cmd/cni/sysctl_windows.go b/cmd/cni/sysctl_windows.go
new file mode 100644
index 00000000000..b3078815ee7
--- /dev/null
+++ b/cmd/cni/sysctl_windows.go
@@ -0,0 +1,6 @@
+package main
+
+func sysctlEnableIPv6(nsPath string) error {
+	// nothing to do on Windows
+	return nil
+}