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>

diff --git a/include/uapi/linux/if_addr.h b/include/uapi/linux/if_addr.h
index cfed10b..dea10a8 100644 (file)
--- a/include/uapi/linux/if_addr.h
+++ b/include/uapi/linux/if_addr.h
@@ -49,6 +49,7 @@ enum {
 #define IFA_F_TENTATIVE                0x40
 #define IFA_F_PERMANENT                0x80
 #define IFA_F_MANAGETEMPADDR   0x100
+#define IFA_F_NOPREFIXROUTE    0x200
 
 struct ifa_cacheinfo {
        __u32   ifa_prefered;

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1b2e4ee..85100c1 100644 (file)
--- 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) {