net: vrf: Add l3mdev rules on first device create

Add l3mdev rule per address family when the first VRF device is
created. The rules are installed with a default preference of 1000.
Users can replace the default rule as desired.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 1b214ea4619a5838d6478a2835f8e73da85bef78..e3e693bf0dec344fd83469cf2ce04797c3bc3cee 100644 (file)
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -35,6 +35,7 @@
 #include <net/route.h>
 #include <net/addrconf.h>
 #include <net/l3mdev.h>
+#include <net/fib_rules.h>
 
 #define RT_FL_TOS(oldflp4) \
        ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
@@ -42,6 +43,9 @@
 #define DRV_NAME       "vrf"
 #define DRV_VERSION    "1.0"
 
+#define FIB_RULE_PREF  1000       /* default preference for FIB rules */
+static bool add_fib_rules = true;
+
 struct net_vrf {
        struct rtable __rcu     *rth;
        struct rtable __rcu     *rth_local;
@@ -897,6 +901,91 @@ static const struct ethtool_ops vrf_ethtool_ops = {
        .get_drvinfo    = vrf_get_drvinfo,
 };
 
+static inline size_t vrf_fib_rule_nl_size(void)
+{
+       size_t sz;
+
+       sz  = NLMSG_ALIGN(sizeof(struct fib_rule_hdr));
+       sz += nla_total_size(sizeof(u8));       /* FRA_L3MDEV */
+       sz += nla_total_size(sizeof(u32));      /* FRA_PRIORITY */
+
+       return sz;
+}
+
+static int vrf_fib_rule(const struct net_device *dev, __u8 family, bool add_it)
+{
+       struct fib_rule_hdr *frh;
+       struct nlmsghdr *nlh;
+       struct sk_buff *skb;
+       int err;
+
+       skb = nlmsg_new(vrf_fib_rule_nl_size(), GFP_KERNEL);
+       if (!skb)
+               return -ENOMEM;
+
+       nlh = nlmsg_put(skb, 0, 0, 0, sizeof(*frh), 0);
+       if (!nlh)
+               goto nla_put_failure;
+
+       /* rule only needs to appear once */
+       nlh->nlmsg_flags &= NLM_F_EXCL;
+
+       frh = nlmsg_data(nlh);
+       memset(frh, 0, sizeof(*frh));
+       frh->family = family;
+       frh->action = FR_ACT_TO_TBL;
+
+       if (nla_put_u32(skb, FRA_L3MDEV, 1))
+               goto nla_put_failure;
+
+       if (nla_put_u32(skb, FRA_PRIORITY, FIB_RULE_PREF))
+               goto nla_put_failure;
+
+       nlmsg_end(skb, nlh);
+
+       /* fib_nl_{new,del}rule handling looks for net from skb->sk */
+       skb->sk = dev_net(dev)->rtnl;
+       if (add_it) {
+               err = fib_nl_newrule(skb, nlh);
+               if (err == -EEXIST)
+                       err = 0;
+       } else {
+               err = fib_nl_delrule(skb, nlh);
+               if (err == -ENOENT)
+                       err = 0;
+       }
+       nlmsg_free(skb);
+
+       return err;
+
+nla_put_failure:
+       nlmsg_free(skb);
+
+       return -EMSGSIZE;
+}
+
+static int vrf_add_fib_rules(const struct net_device *dev)
+{
+       int err;
+
+       err = vrf_fib_rule(dev, AF_INET,  true);
+       if (err < 0)
+               goto out_err;
+
+       err = vrf_fib_rule(dev, AF_INET6, true);
+       if (err < 0)
+               goto ipv6_err;
+
+       return 0;
+
+ipv6_err:
+       vrf_fib_rule(dev, AF_INET,  false);
+
+out_err:
+       netdev_err(dev, "Failed to add FIB rules.\n");
+       return err;
+}
+
 static void vrf_setup(struct net_device *dev)
 {
        ether_setup(dev);
@@ -937,6 +1026,7 @@ static int vrf_newlink(struct net *src_net, struct net_device *dev,
                       struct nlattr *tb[], struct nlattr *data[])
 {
        struct net_vrf *vrf = netdev_priv(dev);
+       int err;
 
        if (!data || !data[IFLA_VRF_TABLE])
                return -EINVAL;
@@ -945,7 +1035,21 @@ static int vrf_newlink(struct net *src_net, struct net_device *dev,
 
        dev->priv_flags |= IFF_L3MDEV_MASTER;
 
-       return register_netdevice(dev);
+       err = register_netdevice(dev);
+       if (err)
+               goto out;
+
+       if (add_fib_rules) {
+               err = vrf_add_fib_rules(dev);
+               if (err) {
+                       unregister_netdevice(dev);
+                       goto out;
+               }
+               add_fib_rules = false;
+       }
+
+out:
+       return err;
 }
 
 static size_t vrf_nl_getsize(const struct net_device *dev)