ipv6 addrconf: add IFA_F_NOPREFIXROUTE flag to suppress creation of IP6 routes

When adding/modifying an IPv6 address, the userspace application needs
a way to suppress adding a prefix route. This is for example relevant
together with IFA_F_MANAGERTEMPADDR, where userspace creates autoconf
generated addresses, but depending on on-link, no route for the
prefix should be added.

Signed-off-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 6 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1b2e4ee3ce5e..85100c1ac761 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2434,8 +2434,11 @@ static int inet6_addr_add(struct net *net, int ifindex,
                             valid_lft, prefered_lft);
 
         if (!IS_ERR(ifp)) {
-                addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev,
-                                      expires, flags);
+                if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) {
+                        addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev,
+                                              expires, flags);
+                }
+
                 /*
                  * Note that section 3.1 of RFC 4429 indicates
                  * that the Optimistic flag should not be set for
@@ -3662,7 +3665,8 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags,
         spin_lock_bh(&ifp->lock);
         was_managetempaddr = ifp->flags & IFA_F_MANAGETEMPADDR;
         ifp->flags &= ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD |
-                        IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR);
+                        IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR |
+                        IFA_F_NOPREFIXROUTE);
         ifp->flags |= ifa_flags;
         ifp->tstamp = jiffies;
         ifp->valid_lft = valid_lft;
@@ -3672,8 +3676,10 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags,
         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 (!(ifa_flags & IFA_F_NOPREFIXROUTE)) {
+                addrconf_prefix_route(&ifp->addr, ifp->prefix_len, ifp->idev->dev,
+                                      expires, flags);
+        }
 
         if (was_managetempaddr || ifp->flags & IFA_F_MANAGETEMPADDR) {
                 if (was_managetempaddr && !(ifp->flags & IFA_F_MANAGETEMPADDR))
@@ -3727,7 +3733,8 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
         ifa_flags = tb[IFA_FLAGS] ? nla_get_u32(tb[IFA_FLAGS]) : ifm->ifa_flags;
 
         /* We ignore other flags so far. */
-        ifa_flags &= IFA_F_NODAD | IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR;
+        ifa_flags &= IFA_F_NODAD | IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR |
+                     IFA_F_NOPREFIXROUTE;
 
         ifa = ipv6_get_ifaddr(net, pfx, dev, 1);
         if (ifa == NULL) {