[PATCH 1/1] fixup! ipv6 addrconf: introduce IFA_F_MANAGETEMPADDR to tell kernel to manage temporary addresses

[Thomas Haller <thaller@redhat.com>]

Handle IFA_F_MANAGETEMPADDR flag when modifying existing addresses too.

Signed-off-by: Thomas Haller <thaller@redhat.com>
---
Hi,

I'd like to suggest this change, I think it makes it easier for the user space
application to set this flag of (potentially) existing addresses.

Note, that if the flag gets cleared if the ifa had it set before
and the temporary addresses will exprire immediatly. This makes sense
for me.

Or if we don't want this, then the command should fail (EEXIST?) when trying
to set MANAGETEMPADDR for an existing address that doesn't have the flag already.

Thomas

 net/ipv6/addrconf.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9e217b8..9e726c8 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3613,20 +3613,21 @@ inet6_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 	return inet6_addr_del(net, ifm->ifa_index, pfx, ifm->ifa_prefixlen);
 }
 
 static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags,
 			     u32 prefered_lft, u32 valid_lft)
 {
 	u32 flags;
 	clock_t expires;
 	unsigned long timeout;
+	int mngtmp;
 
 	if (!valid_lft || (prefered_lft > valid_lft))
 		return -EINVAL;
 
 	timeout = addrconf_timeout_fixup(valid_lft, HZ);
 	if (addrconf_finite_timeout(timeout)) {
 		expires = jiffies_to_clock_t(timeout * HZ);
 		valid_lft = timeout;
 		flags = RTF_EXPIRES;
 	} else {
@@ -3636,35 +3637,48 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags,
 	}
 
 	timeout = addrconf_timeout_fixup(prefered_lft, HZ);
 	if (addrconf_finite_timeout(timeout)) {
 		if (timeout == 0)
 			ifa_flags |= IFA_F_DEPRECATED;
 		prefered_lft = timeout;
 	}
 
 	spin_lock_bh(&ifp->lock);
-	ifp->flags = (ifp->flags & ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD | IFA_F_HOMEADDRESS)) | ifa_flags;
+	if (ifa_flags & IFA_F_MANAGETEMPADDR &&
+	    (ifp->prefix_len != 64 || ifp->flags & IFA_F_TEMPORARY)) {
+		spin_unlock_bh(&ifp->lock);
+		return -EEXIST;
+	}
+	mngtmp = ifp->flags & IFA_F_MANAGETEMPADDR;
+	ifp->flags = (ifp->flags & ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD | IFA_F_HOMEADDRESS |
+				     IFA_F_MANAGETEMPADDR)) | ifa_flags;
 	ifp->tstamp = jiffies;
 	ifp->valid_lft = valid_lft;
 	ifp->prefered_lft = prefered_lft;
 
 	spin_unlock_bh(&ifp->lock);
 	if (!(ifp->flags&IFA_F_TENTATIVE))
 		ipv6_ifa_notify(0, ifp);
 
 	addrconf_prefix_route(&ifp->addr, ifp->prefix_len, ifp->idev->dev,
 			      expires, flags);
 
-	if (ifp->flags & IFA_F_MANAGETEMPADDR)
-		manage_tempaddrs(ifp->idev, ifp, valid_lft, prefered_lft,
+	if (mngtmp && !(ifa_flags & IFA_F_MANAGETEMPADDR)) {
+		/* expire the life time of the temporary addresses */
+		manage_tempaddrs(ifp->idev, ifp, 0, 0,
 				 false, jiffies);
+	} else if (ifa_flags & IFA_F_MANAGETEMPADDR) {
+		/* if we did not yet mngtmp, create temporary addresses */
+		manage_tempaddrs(ifp->idev, ifp, valid_lft, prefered_lft,
+				 !mngtmp, jiffies);
+	}
 
 	addrconf_verify(0);
 
 	return 0;
 }
 
 static int
 inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct net *net = sock_net(skb->sk);
@@ -3710,23 +3724,20 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
 	if (ifa == NULL) {
 		/*
 		 * It would be best to check for !NLM_F_CREATE here but
 		 * userspace alreay relies on not having to provide this.
 		 */
 		return inet6_addr_add(net, ifm->ifa_index, pfx, peer_pfx,
 				      ifm->ifa_prefixlen, ifa_flags,
 				      preferred_lft, valid_lft);
 	}
 
-	/* We ignore IFA_F_MANAGETEMPADDR for modify. */
-	ifa_flags &= ~IFA_F_MANAGETEMPADDR;
-
 	if (nlh->nlmsg_flags & NLM_F_EXCL ||
 	    !(nlh->nlmsg_flags & NLM_F_REPLACE))
 		err = -EEXIST;
 	else
 		err = inet6_addr_modify(ifa, ifa_flags, preferred_lft, valid_lft);
 
 	in6_ifa_put(ifa);
 
 	return err;
 }
-- 
1.8.4.1.559.gdb9bdfb