From 6b0aa1db32a955c9972f09654edebf58b2c37c8c Mon Sep 17 00:00:00 2001
From: Adrian Pistol <vifino@tty.sh>
Date: Tue, 25 Apr 2023 18:37:27 +0200
Subject: [PATCH] link: add LinkSetIP6AddrGenMode

---
 handle_unspecified.go  |  4 ++++
 link_linux.go          | 29 +++++++++++++++++++++++++++++
 netlink_unspecified.go |  4 ++++
 nl/link_linux.go       |  7 +++++++
 4 files changed, 44 insertions(+)

diff --git a/handle_unspecified.go b/handle_unspecified.go
index 693ca0a5..4e6231f2 100644
--- a/handle_unspecified.go
+++ b/handle_unspecified.go
@@ -171,6 +171,10 @@ func (h *Handle) LinkSetGROMaxSize(link Link, maxSize int) error {
 	return ErrNotImplemented
 }
 
+func (h *Handle) LinkSetIP6AddrGenMode(link Link, mode int) error {
+	return ErrNotImplemented
+}
+
 func (h *Handle) setProtinfoAttr(link Link, mode bool, attr int) error {
 	return ErrNotImplemented
 }
diff --git a/link_linux.go b/link_linux.go
index 524a93bb..988461dd 100644
--- a/link_linux.go
+++ b/link_linux.go
@@ -1010,6 +1010,35 @@ func (h *Handle) LinkSetGROMaxSize(link Link, maxSize int) error {
 	return err
 }
 
+// LinkSetIP6AddrGenMode sets the IPv6 address generation mode of the link device.
+// Equivalent to: `ip link set $link addrgenmode $mode`
+func LinkSetIP6AddrGenMode(link Link, mode int) error {
+	return pkgHandle.LinkSetIP6AddrGenMode(link, mode)
+}
+
+// LinkSetIP6AddrGenMode sets the IPv6 address generation mode of the link device.
+// Equivalent to: `ip link set $link addrgenmode $mode`
+func (h *Handle) LinkSetIP6AddrGenMode(link Link, mode int) error {
+	base := link.Attrs()
+	h.ensureIndex(base)
+	req := h.newNetlinkRequest(unix.RTM_SETLINK, unix.NLM_F_ACK)
+
+	msg := nl.NewIfInfomsg(unix.AF_UNSPEC)
+	msg.Index = int32(base.Index)
+	req.AddData(msg)
+
+	b := make([]byte, 1)
+	b[0] = uint8(mode)
+
+	data := nl.NewRtAttr(unix.IFLA_INET6_ADDR_GEN_MODE, b)
+	af := nl.NewRtAttr(unix.AF_INET6, data.Serialize())
+	spec := nl.NewRtAttr(unix.IFLA_AF_SPEC, af.Serialize())
+	req.AddData(spec)
+
+	_, err := req.Execute(unix.NETLINK_ROUTE, 0)
+	return err
+}
+
 func boolAttr(val bool) []byte {
 	var v uint8
 	if val {
diff --git a/netlink_unspecified.go b/netlink_unspecified.go
index c6419490..d1b9d455 100644
--- a/netlink_unspecified.go
+++ b/netlink_unspecified.go
@@ -132,6 +132,10 @@ func LinkSetGROMaxSize(link Link, maxSize int) error {
 	return ErrNotImplemented
 }
 
+func LinkSetIP6AddrGenMode(link Link, mode int) error {
+	return ErrNotImplemented
+}
+
 func LinkAdd(link Link) error {
 	return ErrNotImplemented
 }
diff --git a/nl/link_linux.go b/nl/link_linux.go
index e10edbc0..49913606 100644
--- a/nl/link_linux.go
+++ b/nl/link_linux.go
@@ -718,3 +718,10 @@ const (
 	IFLA_BAREUDP_MULTIPROTO_MODE
 	IFLA_BAREUDP_MAX = IFLA_BAREUDP_MULTIPROTO_MODE
 )
+
+const (
+	IN6_ADDR_GEN_MODE_EUI64 = iota
+	IN6_ADDR_GEN_MODE_NONE
+	IN6_ADDR_GEN_MODE_STABLE_PRIVACY
+	IN6_ADDR_GEN_MODE_RANDOM
+)