Add net.vrf.strict_mode sysctl parameter.
When net.vrf.strict_mode=0 (default) it is possible to associate multiple
VRF devices to the same table. Conversely, when net.vrf.strict_mode=1 a
table can be associated to a single VRF device.
When switching from net.vrf.strict_mode=0 to net.vrf.strict_mode=1, a check
is performed to verify that all tables have at most one VRF associated,
otherwise the switch is not allowed.
The net.vrf.strict_mode parameter is per network namespace.
Signed-off-by: Andrea Mayer <andrea.mayer@xxxxxxxxxxx>
---
drivers/net/vrf.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 119 insertions(+)
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index f772aac6a04c..bac118b615bc 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -102,6 +102,7 @@ struct netns_vrf {
bool add_fib_rules;
struct vrf_map vmap;
+ struct ctl_table_header *ctl_hdr;
};
struct net_vrf {
@@ -245,6 +246,52 @@ static void vrf_map_unlock(struct vrf_map *vmap) __releases(&vmap->vmap_lock)
spin_unlock(&vmap->vmap_lock);
}
+static bool vrf_strict_mode(struct vrf_map *vmap)
+{
+ bool strict_mode;
+
+ vrf_map_lock(vmap);
+ strict_mode = vmap->strict_mode;
+ vrf_map_unlock(vmap);
+
+ return strict_mode;
+}
+
+static int vrf_strict_mode_change(struct vrf_map *vmap, bool new_mode)
+{
+ bool *cur_mode;
+ int res = 0;
+
+ vrf_map_lock(vmap);
+
+ cur_mode = &vmap->strict_mode;
+ if (*cur_mode == new_mode)
+ goto unlock;
+
+ if (*cur_mode) {
+ /* disable strict mode */
+ *cur_mode = false;
+ } else {
+ if (vmap->shared_tables) {
+ /* we cannot allow strict_mode because there are some
+ * vrfs that share one or more tables.
+ */
+ res = -EBUSY;
+ goto unlock;
+ }
+
+ /* no tables are shared among vrfs, so we can go back
+ * to 1:1 association between a vrf with its table.
+ */
+ *cur_mode = true;
+ }
+
+unlock:
+ vrf_map_unlock(vmap);
+
+ return res;
+}
+
/* called with rtnl lock held */
static int
vrf_map_register_dev(struct net_device *dev, struct netlink_ext_ack *extack)
@@ -1701,19 +1748,91 @@ static int vrf_map_init(struct vrf_map *vmap)
return 0;
}
+static int vrf_shared_table_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ struct net *net = (struct net *)table->extra1;
+ struct vrf_map *vmap = netns_vrf_map(net);
+ int proc_strict_mode = 0;
+ struct ctl_table tmp = {
+ .procname = table->procname,
+ .data = &proc_strict_mode,
+ .maxlen = sizeof(int),
+ .mode = table->mode,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ };
+ int ret;
+
+ if (!write)
+ proc_strict_mode = vrf_strict_mode(vmap);
+
+ ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+
+ if (write && ret == 0)
+ ret = vrf_strict_mode_change(vmap, (bool)proc_strict_mode);
+
+ return ret;
+}
+
+static const struct ctl_table vrf_table[] = {
+ {
+ .procname = "strict_mode",
+ .data = NULL,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = vrf_shared_table_handler,
+ /* set by the vrf_netns_init */
+ .extra1 = NULL,
+ },
+ { },
+};
+
/* Initialize per network namespace state */
static int __net_init vrf_netns_init(struct net *net)
{
struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id);
+ struct ctl_table *table;
+ int res;
nn_vrf->add_fib_rules = true;
vrf_map_init(&nn_vrf->vmap);
+ table = kmemdup(vrf_table, sizeof(vrf_table), GFP_KERNEL);
+ if (!table)
+ return -ENOMEM;
+
+ /* init the extra1 parameter with the reference to current netns */
+ table[0].extra1 = net;
+
+ nn_vrf->ctl_hdr = register_net_sysctl(net, "net/vrf", table);
+ if (!nn_vrf->ctl_hdr) {
+ res = -ENOMEM;
+ goto free_table;
+ }
+
return 0;
+
+free_table:
+ kfree(table);
+
+ return res;
+}
+
+static void __net_exit vrf_netns_exit(struct net *net)
+{
+ struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id);
+ struct ctl_table *table;
+
+ table = nn_vrf->ctl_hdr->ctl_table_arg;
+ unregister_net_sysctl_table(nn_vrf->ctl_hdr);
+ kfree(table);
}
static struct pernet_operations vrf_net_ops __net_initdata = {
.init = vrf_netns_init,
+ .exit = vrf_netns_exit,
.id = &vrf_net_id,
.size = sizeof(struct netns_vrf),
};
--
2.20.1
