| Message ID | e6dcb4c793eda200142ae7834c1e342f994451cf.1472815982.git.jbenc@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index c0dda6fc0921..6358e35d74b7 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2842,6 +2842,9 @@ static int vxlan_dev_configure(struct net *src_net, struct net_device *dev, dev->mtu = lowerdev->mtu - (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM); needed_headroom = lowerdev->hard_header_len; + } else if (vxlan_addr_multicast(&dst->remote_ip)) { + pr_info("multicast destination requires interface to be specified\n"); + return -EINVAL; } if (conf->mtu) {
Currently, kernel accepts configurations such as: ip l a type vxlan dstport 4789 id 1 group 239.192.0.1 ip l a type vxlan dstport 4789 id 1 group ff0e::110 However, neither of those really works. In the IPv4 case, the interface cannot be brought up ("RTNETLINK answers: No such device"). This is because multicast join will be rejected without the interface being specified. In the IPv6 case, multicast wil be joined on the first interface found. This is not what the user wants as it depends on random factors (order of interfaces). Note that it's possible to add a local address but it doesn't solve anything. For IPv4, it's not considered in the multicast join (thus the same error as above is returned on ifup). This could be added but it wouldn't help for IPv6 anyway. For IPv6, we do need the interface. Just reject a configuration that sets multicast address and does not provide an interface. Nobody can depend on the previous behavior as it never worked. Signed-off-by: Jiri Benc <jbenc@redhat.com> --- drivers/net/vxlan.c | 3 +++ 1 file changed, 3 insertions(+)