net/ipv6: Add support for onlink flag
Similar to IPv4 allow routes to be added with the RTNH_F_ONLINK flag.
The onlink option requires a gateway and a nexthop device. Any unicast
gateway is allowed (including IPv4 mapped addresses and unresolved
ones) as long as the gateway is not a local address and if it resolves
it must match the given device.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index db27086..fe3966a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2470,6 +2470,31 @@ static struct rt6_info *ip6_nh_lookup_table(struct net *net,
return rt;
}
+static int ip6_route_check_nh_onlink(struct net *net,
+ struct fib6_config *cfg,
+ struct net_device *dev,
+ struct netlink_ext_ack *extack)
+{
+ u32 tbid = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
+ const struct in6_addr *gw_addr = &cfg->fc_gateway;
+ u32 flags = RTF_LOCAL | RTF_ANYCAST | RTF_REJECT;
+ struct rt6_info *grt;
+ int err;
+
+ err = 0;
+ grt = ip6_nh_lookup_table(net, cfg, gw_addr, tbid, 0);
+ if (grt) {
+ if (grt->rt6i_flags & flags || dev != grt->dst.dev) {
+ NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
+ err = -EINVAL;
+ }
+
+ ip6_rt_put(grt);
+ }
+
+ return err;
+}
+
static int ip6_route_check_nh(struct net *net,
struct fib6_config *cfg,
struct net_device **_dev,
@@ -2572,6 +2597,21 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
if (cfg->fc_metric == 0)
cfg->fc_metric = IP6_RT_PRIO_USER;
+ if (cfg->fc_flags & RTNH_F_ONLINK) {
+ if (!dev) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop device required for onlink");
+ err = -ENODEV;
+ goto out;
+ }
+
+ if (!(dev->flags & IFF_UP)) {
+ NL_SET_ERR_MSG(extack, "Nexthop device is not up");
+ err = -ENETDOWN;
+ goto out;
+ }
+ }
+
err = -ENOBUFS;
if (cfg->fc_nlinfo.nlh &&
!(cfg->fc_nlinfo.nlh->nlmsg_flags & NLM_F_CREATE)) {
@@ -2732,7 +2772,12 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
goto out;
}
- err = ip6_route_check_nh(net, cfg, &dev, &idev);
+ if (cfg->fc_flags & RTNH_F_ONLINK) {
+ err = ip6_route_check_nh_onlink(net, cfg, dev,
+ extack);
+ } else {
+ err = ip6_route_check_nh(net, cfg, &dev, &idev);
+ }
if (err)
goto out;
}
@@ -2774,6 +2819,7 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
if (!(rt->rt6i_flags & (RTF_LOCAL | RTF_ANYCAST)) &&
!netif_carrier_ok(dev))
rt->rt6i_nh_flags |= RTNH_F_LINKDOWN;
+ rt->rt6i_nh_flags |= (cfg->fc_flags & RTNH_F_ONLINK);
rt->dst.dev = dev;
rt->rt6i_idev = idev;
rt->rt6i_table = table;
@@ -3843,6 +3889,8 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
if (rtm->rtm_flags & RTM_F_CLONED)
cfg->fc_flags |= RTF_CACHE;
+ cfg->fc_flags |= (rtm->rtm_flags & RTNH_F_ONLINK);
+
cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
cfg->fc_nlinfo.nlh = nlh;
cfg->fc_nlinfo.nl_net = sock_net(skb->sk);
@@ -4248,6 +4296,7 @@ static int rt6_nexthop_info(struct sk_buff *skb, struct rt6_info *rt,
goto nla_put_failure;
}
+ *flags |= (rt->rt6i_nh_flags & RTNH_F_ONLINK);
if (rt->rt6i_nh_flags & RTNH_F_OFFLOAD)
*flags |= RTNH_F_OFFLOAD;