Add the data structures and the processing logic to keep track of the associations between VRF devices and routing tables. When a VRF is instantiated, it needs to refer to a given routing table. For each table, we explicitly keep track of the existing VRFs that refer to the table.
Signed-off-by: Andrea Mayer andrea.mayer@uniroma2.it --- drivers/net/vrf.c | 273 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 268 insertions(+), 5 deletions(-)
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c index 43928a1c2f2a..098fdabaa4c5 100644 --- a/drivers/net/vrf.c +++ b/drivers/net/vrf.c @@ -21,6 +21,7 @@ #include <net/rtnetlink.h> #include <linux/u64_stats_sync.h> #include <linux/hashtable.h> +#include <linux/spinlock_types.h>
#include <linux/inetdevice.h> #include <net/arp.h> @@ -35,12 +36,75 @@ #include <net/netns/generic.h>
#define DRV_NAME "vrf" -#define DRV_VERSION "1.0" +#define DRV_VERSION "1.1"
#define FIB_RULE_PREF 1000 /* default preference for FIB rules */
+#define HT_MAP_BITS 4 +#define HASH_INITVAL ((u32)0xcafef00d) + +struct vrf_map { + DECLARE_HASHTABLE(ht, HT_MAP_BITS); + spinlock_t vmap_lock; + + /* shared_tables: + * count how many distinct tables do not comply with the strict mode + * requirement. + * shared_tables value must be 0 in order to enable the strict mode. + * + * example of the evolution of shared_tables: + * | time + * add vrf0 --> table 100 shared_tables = 0 | t0 + * add vrf1 --> table 101 shared_tables = 0 | t1 + * add vrf2 --> table 100 shared_tables = 1 | t2 + * add vrf3 --> table 100 shared_tables = 1 | t3 + * add vrf4 --> table 101 shared_tables = 2 v t4 + * + * shared_tables is a "step function" (or "staircase function") + * and it is increased by one when the second vrf is associated to a + * table. + * + * at t2, vrf0 and vrf2 are bound to table 100: shared_tables = 1. + * + * at t3, another dev (vrf3) is bound to the same table 100 but the + * value of shared_tables is still 1. + * This means that no matter how many new vrfs will register on the + * table 100, the shared_tables will not increase (considering only + * table 100). + * + * at t4, vrf4 is bound to table 101, and shared_tables = 2. + * + * Looking at the value of shared_tables we can immediately know if + * the strict_mode can or cannot be enforced. Indeed, strict_mode + * can be enforced iff shared_tables = 0. + * + * Conversely, shared_tables is decreased when a vrf is de-associated + * from a table with exactly two associated vrfs. + */ + u32 shared_tables; + + bool strict_mode; +}; + +struct vrf_map_elem { + struct hlist_node hnode; + struct list_head vrf_list; /* VRFs registered to this table */ + + u32 table_id; + int users; + int ifindex; +}; + static unsigned int vrf_net_id;
+/* per netns vrf data */ +struct netns_vrf { + /* protected by rtnl lock */ + bool add_fib_rules; + + struct vrf_map vmap; +}; + struct net_vrf { struct rtable __rcu *rth; struct rt6_info __rcu *rt6; @@ -48,6 +112,9 @@ struct net_vrf { struct fib6_table *fib6_table; #endif u32 tb_id; + + struct list_head me_list; /* entry in vrf_map_elem */ + int ifindex; };
struct pcpu_dstats { @@ -103,6 +170,173 @@ static void vrf_get_stats64(struct net_device *dev, } }
+static struct vrf_map *netns_vrf_map(struct net *net) +{ + struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id); + + return &nn_vrf->vmap; +} + +static struct vrf_map *netns_vrf_map_by_dev(struct net_device *dev) +{ + return netns_vrf_map(dev_net(dev)); +} + +static struct vrf_map_elem *vrf_map_elem_alloc(gfp_t flags) +{ + struct vrf_map_elem *me; + + me = kmalloc(sizeof(*me), flags); + if (!me) + return NULL; + + return me; +} + +static void vrf_map_elem_free(struct vrf_map_elem *me) +{ + kfree(me); +} + +static void vrf_map_elem_init(struct vrf_map_elem *me, int table_id, + int ifindex, int users) +{ + me->table_id = table_id; + me->ifindex = ifindex; + me->users = users; + INIT_LIST_HEAD(&me->vrf_list); +} + +static struct vrf_map_elem *vrf_map_lookup_elem(struct vrf_map *vmap, + u32 table_id) +{ + struct vrf_map_elem *me; + u32 key; + + key = jhash_1word(table_id, HASH_INITVAL); + hash_for_each_possible(vmap->ht, me, hnode, key) { + if (me->table_id == table_id) + return me; + } + + return NULL; +} + +static void vrf_map_add_elem(struct vrf_map *vmap, struct vrf_map_elem *me) +{ + u32 table_id = me->table_id; + u32 key; + + key = jhash_1word(table_id, HASH_INITVAL); + hash_add(vmap->ht, &me->hnode, key); +} + +static void vrf_map_del_elem(struct vrf_map_elem *me) +{ + hash_del(&me->hnode); +} + +static void vrf_map_lock(struct vrf_map *vmap) __acquires(&vmap->vmap_lock) +{ + spin_lock(&vmap->vmap_lock); +} + +static void vrf_map_unlock(struct vrf_map *vmap) __releases(&vmap->vmap_lock) +{ + spin_unlock(&vmap->vmap_lock); +} + +/* called with rtnl lock held */ +static int +vrf_map_register_dev(struct net_device *dev, struct netlink_ext_ack *extack) +{ + struct vrf_map *vmap = netns_vrf_map_by_dev(dev); + struct net_vrf *vrf = netdev_priv(dev); + struct vrf_map_elem *new_me, *me; + u32 table_id = vrf->tb_id; + bool free_new_me = false; + int users; + int res; + + /* we pre-allocate elements used in the spin-locked section (so that we + * keep the spinlock as short as possibile). + */ + new_me = vrf_map_elem_alloc(GFP_KERNEL); + if (!new_me) + return -ENOMEM; + + vrf_map_elem_init(new_me, table_id, dev->ifindex, 0); + + vrf_map_lock(vmap); + + me = vrf_map_lookup_elem(vmap, table_id); + if (!me) { + me = new_me; + vrf_map_add_elem(vmap, me); + goto link_vrf; + } + + /* we already have an entry in the vrf_map, so it means there is (at + * least) a vrf registered on the specific table. + */ + free_new_me = true; + if (vmap->strict_mode) { + /* vrfs cannot share the same table */ + NL_SET_ERR_MSG(extack, "Table is used by another VRF"); + res = -EBUSY; + goto unlock; + } + +link_vrf: + users = ++me->users; + if (users == 2) + ++vmap->shared_tables; + + list_add(&vrf->me_list, &me->vrf_list); + + res = 0; + +unlock: + vrf_map_unlock(vmap); + + /* clean-up, if needed */ + if (free_new_me) + vrf_map_elem_free(new_me); + + return res; +} + +/* called with rtnl lock held */ +static void vrf_map_unregister_dev(struct net_device *dev) +{ + struct vrf_map *vmap = netns_vrf_map_by_dev(dev); + struct net_vrf *vrf = netdev_priv(dev); + u32 table_id = vrf->tb_id; + struct vrf_map_elem *me; + int users; + + vrf_map_lock(vmap); + + me = vrf_map_lookup_elem(vmap, table_id); + if (!me) + goto unlock; + + list_del(&vrf->me_list); + + users = --me->users; + if (users == 1) { + --vmap->shared_tables; + } else if (users == 0) { + vrf_map_del_elem(me); + + /* no one will refer to this element anymore */ + vrf_map_elem_free(me); + } + +unlock: + vrf_map_unlock(vmap); +} + /* by default VRF devices do not have a qdisc and are expected * to be created with only a single queue. */ @@ -1319,6 +1553,8 @@ static void vrf_dellink(struct net_device *dev, struct list_head *head) netdev_for_each_lower_dev(dev, port_dev, iter) vrf_del_slave(dev, port_dev);
+ vrf_map_unregister_dev(dev); + unregister_netdevice_queue(dev, head); }
@@ -1327,6 +1563,7 @@ static int vrf_newlink(struct net *src_net, struct net_device *dev, struct netlink_ext_ack *extack) { struct net_vrf *vrf = netdev_priv(dev); + struct netns_vrf *nn_vrf; bool *add_fib_rules; struct net *net; int err; @@ -1349,11 +1586,26 @@ static int vrf_newlink(struct net *src_net, struct net_device *dev, if (err) goto out;
+ /* mapping between table_id and vrf; + * note: such binding could not be done in the dev init function + * because dev->ifindex id is not available yet. + */ + vrf->ifindex = dev->ifindex; + + err = vrf_map_register_dev(dev, extack); + if (err) { + unregister_netdevice(dev); + goto out; + } + net = dev_net(dev); - add_fib_rules = net_generic(net, vrf_net_id); + nn_vrf = net_generic(net, vrf_net_id); + + add_fib_rules = &nn_vrf->add_fib_rules; if (*add_fib_rules) { err = vrf_add_fib_rules(dev); if (err) { + vrf_map_unregister_dev(dev); unregister_netdevice(dev); goto out; } @@ -1440,12 +1692,23 @@ static struct notifier_block vrf_notifier_block __read_mostly = { .notifier_call = vrf_device_event, };
+static int vrf_map_init(struct vrf_map *vmap) +{ + spin_lock_init(&vmap->vmap_lock); + hash_init(vmap->ht); + + vmap->strict_mode = false; + + return 0; +} + /* Initialize per network namespace state */ static int __net_init vrf_netns_init(struct net *net) { - bool *add_fib_rules = net_generic(net, vrf_net_id); + struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id);
- *add_fib_rules = true; + nn_vrf->add_fib_rules = true; + vrf_map_init(&nn_vrf->vmap);
return 0; } @@ -1453,7 +1716,7 @@ static int __net_init vrf_netns_init(struct net *net) static struct pernet_operations vrf_net_ops __net_initdata = { .init = vrf_netns_init, .id = &vrf_net_id, - .size = sizeof(bool), + .size = sizeof(struct netns_vrf), };
static int __init vrf_init_module(void)