ipvlan: introduce 'private' attribute for all existing modes.

IPvlan has always operated in bridge mode. However there are scenarios
where each slave should be able to talk through the master device but
not necessarily across each other. Think of an environment where each
of a namespace is a private and independant customer. In this scenario
the machine which is hosting these namespaces neither want to tell who
their neighbor is nor the individual namespaces care to talk to neighbor
on short-circuited network path.

This patch implements the mode that is very similar to the 'private' mode
in macvlan where individual slaves can send and receive traffic through
the master device, just that they can not talk among slave devices.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 36 insertions, 2 deletions

diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index f0ab55df57f1..4368afb1934c 100644
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -462,11 +462,24 @@ static int ipvlan_nl_changelink(struct net_device *dev,
         struct ipvl_port *port = ipvlan_port_get_rtnl(ipvlan->phy_dev);
         int err = 0;
 
-        if (data && data[IFLA_IPVLAN_MODE]) {
+        if (!data)
+                return 0;
+
+        if (data[IFLA_IPVLAN_MODE]) {
                 u16 nmode = nla_get_u16(data[IFLA_IPVLAN_MODE]);
 
                 err = ipvlan_set_port_mode(port, nmode);
         }
+
+        if (!err && data[IFLA_IPVLAN_FLAGS]) {
+                u16 flags = nla_get_u16(data[IFLA_IPVLAN_FLAGS]);
+
+                if (flags & IPVLAN_F_PRIVATE)
+                        ipvlan_mark_private(port);
+                else
+                        ipvlan_clear_private(port);
+        }
+
         return err;
 }
 
@@ -474,18 +487,30 @@ static size_t ipvlan_nl_getsize(const struct net_device *dev)
 {
         return (0
                 + nla_total_size(2) /* IFLA_IPVLAN_MODE */
+                + nla_total_size(2) /* IFLA_IPVLAN_FLAGS */
                 );
 }
 
 static int ipvlan_nl_validate(struct nlattr *tb[], struct nlattr *data[],
                               struct netlink_ext_ack *extack)
 {
-        if (data && data[IFLA_IPVLAN_MODE]) {
+        if (!data)
+                return 0;
+
+        if (data[IFLA_IPVLAN_MODE]) {
                 u16 mode = nla_get_u16(data[IFLA_IPVLAN_MODE]);
 
                 if (mode < IPVLAN_MODE_L2 || mode >= IPVLAN_MODE_MAX)
                         return -EINVAL;
         }
+        if (data[IFLA_IPVLAN_FLAGS]) {
+                u16 flags = nla_get_u16(data[IFLA_IPVLAN_FLAGS]);
+
+                /* Only one bit is used at this moment. */
+                if (flags & ~IPVLAN_F_PRIVATE)
+                        return -EINVAL;
+        }
+
         return 0;
 }
 
@@ -502,6 +527,8 @@ static int ipvlan_nl_fillinfo(struct sk_buff *skb,
         ret = -EMSGSIZE;
         if (nla_put_u16(skb, IFLA_IPVLAN_MODE, port->mode))
                 goto err;
+        if (nla_put_u16(skb, IFLA_IPVLAN_FLAGS, port->flags))
+                goto err;
 
         return 0;
 
@@ -549,6 +576,12 @@ int ipvlan_link_new(struct net *src_net, struct net_device *dev,
         ipvlan_adjust_mtu(ipvlan, phy_dev);
         INIT_LIST_HEAD(&ipvlan->addrs);
 
+        /* Flags are per port and latest update overrides. User has
+         * to be consistent in setting it just like the mode attribute.
+         */
+        if (data && data[IFLA_IPVLAN_FLAGS])
+                ipvlan->port->flags = nla_get_u16(data[IFLA_IPVLAN_FLAGS]);
+
         /* If the port-id base is at the MAX value, then wrap it around and
          * begin from 0x1 again. This may be due to a busy system where lots
          * of slaves are getting created and deleted.
@@ -644,6 +677,7 @@ EXPORT_SYMBOL_GPL(ipvlan_link_setup);
 static const struct nla_policy ipvlan_nl_policy[IFLA_IPVLAN_MAX + 1] =
 {
         [IFLA_IPVLAN_MODE] = { .type = NLA_U16 },
+        [IFLA_IPVLAN_FLAGS] = { .type = NLA_U16 },
 };
 
 static struct rtnl_link_ops ipvlan_link_ops = {