Re: [PATCH net-next 3/3] net/ipv6: Add support for onlink flag

[David Miller]

From: David Ahern 
Date: Wed, 24 Jan 2018 15:08:39 -0700

> On 1/23/18 8:00 PM, David Ahern wrote:
>> +tbid = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
>> +if (cfg->fc_table && cfg->fc_table != tbid) {
>> +NL_SET_ERR_MSG(extack,
>> +   "Table id mismatch between given table and 
>> device");
>> +return -EINVAL;
>> +}
>> +
>> +cfg->fc_table = tbid;
>> +
>> +return 0;
> 
> This table check is too restrictive for some PBR cases.
> 
> Dave: please drop this set; I'll repost.

Ok.

Re: [PATCH net-next 3/3] net/ipv6: Add support for onlink flag

[David Ahern]

On 1/23/18 8:00 PM, David Ahern wrote:
> + tbid = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
> + if (cfg->fc_table && cfg->fc_table != tbid) {
> + NL_SET_ERR_MSG(extack,
> +"Table id mismatch between given table and 
> device");
> + return -EINVAL;
> + }
> +
> + cfg->fc_table = tbid;
> +
> + return 0;

This table check is too restrictive for some PBR cases.

Dave: please drop this set; I'll repost.

[PATCH net-next 3/3] net/ipv6: Add support for onlink flag

[David Ahern]

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 
---
 net/ipv6/route.c | 69 +++-
 1 file changed, 68 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 00acf0103037..842b2646f1c0 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2470,6 +2470,58 @@ static struct rt6_info *ip6_nh_lookup_table(struct net 
*net,
return rt;
 }
 
+static int ip6_route_onlink_check(struct fib6_config *cfg,
+ struct net_device *dev,
+ struct netlink_ext_ack *extack)
+{
+   u32 tbid;
+
+   if (!dev) {
+   NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
+   return -ENODEV;
+   }
+
+   if (!(dev->flags & IFF_UP)) {
+   NL_SET_ERR_MSG(extack, "Nexthop device is not up");
+   return -ENETDOWN;
+   }
+
+   tbid = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
+   if (cfg->fc_table && cfg->fc_table != tbid) {
+   NL_SET_ERR_MSG(extack,
+  "Table id mismatch between given table and 
device");
+   return -EINVAL;
+   }
+
+   cfg->fc_table = tbid;
+
+   return 0;
+}
+
+static int ip6_route_check_nh_onlink(struct net *net,
+struct fib6_config *cfg,
+struct net_device *dev,
+struct netlink_ext_ack *extack)
+{
+   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, 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,
@@ -2571,6 +2623,12 @@ 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) {
+   err = ip6_route_onlink_check(cfg, dev, extack);
+   if (err)
+   goto out;
+   }
+
err = -ENOBUFS;
if (cfg->fc_nlinfo.nlh &&
!(cfg->fc_nlinfo.nlh->nlmsg_flags & NLM_F_CREATE)) {
@@ -2731,7 +2789,12 @@ 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;
}
@@ -2767,6 +2830,7 @@ 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;
@@ -3836,6 +3900,8 @@ 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);
@@ -4241,6 +4307,7 @@ 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;
 
-- 
2.11.0