* notifier hook walks the map we know that new dev references can not be
* added by the user because core infrastructure ensures dev_get_by_index()
* calls will fail at this point.
+ *
+ * The devmap_hash type is a map type which interprets keys as ifindexes and
+ * indexes these using a hashmap. This allows maps that use ifindex as key to be
+ * densely packed instead of having holes in the lookup array for unused
+ * ifindexes. The setup and packet enqueue/send code is shared between the two
+ * types of devmap; only the lookup and insertion is different.
*/
#include <linux/bpf.h>
#include <net/xdp.h>
struct bpf_dtab_netdev {
struct net_device *dev; /* must be first member, due to tracepoint */
+ struct hlist_node index_hlist;
struct bpf_dtab *dtab;
struct xdp_bulk_queue __percpu *bulkq;
struct rcu_head rcu;
struct bpf_dtab_netdev **netdev_map;
struct list_head __percpu *flush_list;
struct list_head list;
+
+ /* these are only used for DEVMAP_HASH type maps */
+ struct hlist_head *dev_index_head;
+ spinlock_t index_lock;
+ unsigned int items;
+ u32 n_buckets;
};
static DEFINE_SPINLOCK(dev_map_lock);
static LIST_HEAD(dev_map_list);
+static struct hlist_head *dev_map_create_hash(unsigned int entries)
+{
+ int i;
+ struct hlist_head *hash;
+
+ hash = kmalloc_array(entries, sizeof(*hash), GFP_KERNEL);
+ if (hash != NULL)
+ for (i = 0; i < entries; i++)
+ INIT_HLIST_HEAD(&hash[i]);
+
+ return hash;
+}
+
static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
{
int err, cpu;
cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
cost += sizeof(struct list_head) * num_possible_cpus();
+ if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+ dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
+
+ if (!dtab->n_buckets) /* Overflow check */
+ return -EINVAL;
+ cost += sizeof(struct hlist_head) * dtab->n_buckets;
+ }
+
/* if map size is larger than memlock limit, reject it */
err = bpf_map_charge_init(&dtab->map.memory, cost);
if (err)
if (!dtab->netdev_map)
goto free_percpu;
+ if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+ dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets);
+ if (!dtab->dev_index_head)
+ goto free_map_area;
+
+ spin_lock_init(&dtab->index_lock);
+ }
+
return 0;
+free_map_area:
+ bpf_map_area_free(dtab->netdev_map);
free_percpu:
free_percpu(dtab->flush_list);
free_charge:
free_percpu(dtab->flush_list);
bpf_map_area_free(dtab->netdev_map);
+ kfree(dtab->dev_index_head);
kfree(dtab);
}
return 0;
}
+static inline struct hlist_head *dev_map_index_hash(struct bpf_dtab *dtab,
+ int idx)
+{
+ return &dtab->dev_index_head[idx & (dtab->n_buckets - 1)];
+}
+
+struct bpf_dtab_netdev *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key)
+{
+ struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+ struct hlist_head *head = dev_map_index_hash(dtab, key);
+ struct bpf_dtab_netdev *dev;
+
+ hlist_for_each_entry_rcu(dev, head, index_hlist)
+ if (dev->idx == key)
+ return dev;
+
+ return NULL;
+}
+
+static int dev_map_hash_get_next_key(struct bpf_map *map, void *key,
+ void *next_key)
+{
+ struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+ u32 idx, *next = next_key;
+ struct bpf_dtab_netdev *dev, *next_dev;
+ struct hlist_head *head;
+ int i = 0;
+
+ if (!key)
+ goto find_first;
+
+ idx = *(u32 *)key;
+
+ dev = __dev_map_hash_lookup_elem(map, idx);
+ if (!dev)
+ goto find_first;
+
+ next_dev = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&dev->index_hlist)),
+ struct bpf_dtab_netdev, index_hlist);
+
+ if (next_dev) {
+ *next = next_dev->idx;
+ return 0;
+ }
+
+ i = idx & (dtab->n_buckets - 1);
+ i++;
+
+ find_first:
+ for (; i < dtab->n_buckets; i++) {
+ head = dev_map_index_hash(dtab, i);
+
+ next_dev = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
+ struct bpf_dtab_netdev,
+ index_hlist);
+ if (next_dev) {
+ *next = next_dev->idx;
+ return 0;
+ }
+ }
+
+ return -ENOENT;
+}
+
static int bq_xmit_all(struct xdp_bulk_queue *bq, u32 flags,
bool in_napi_ctx)
{
return dev ? &dev->ifindex : NULL;
}
+static void *dev_map_hash_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_dtab_netdev *obj = __dev_map_hash_lookup_elem(map,
+ *(u32 *)key);
+ struct net_device *dev = obj ? obj->dev : NULL;
+
+ return dev ? &dev->ifindex : NULL;
+}
+
static void dev_map_flush_old(struct bpf_dtab_netdev *dev)
{
if (dev->dev->netdev_ops->ndo_xdp_xmit) {
return 0;
}
+static int dev_map_hash_delete_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+ struct bpf_dtab_netdev *old_dev;
+ int k = *(u32 *)key;
+ unsigned long flags;
+ int ret = -ENOENT;
+
+ spin_lock_irqsave(&dtab->index_lock, flags);
+
+ old_dev = __dev_map_hash_lookup_elem(map, k);
+ if (old_dev) {
+ dtab->items--;
+ hlist_del_init_rcu(&old_dev->index_hlist);
+ call_rcu(&old_dev->rcu, __dev_map_entry_free);
+ ret = 0;
+ }
+ spin_unlock_irqrestore(&dtab->index_lock, flags);
+
+ return ret;
+}
+
static struct bpf_dtab_netdev *__dev_map_alloc_node(struct net *net,
struct bpf_dtab *dtab,
u32 ifindex,
map, key, value, map_flags);
}
+static int __dev_map_hash_update_elem(struct net *net, struct bpf_map *map,
+ void *key, void *value, u64 map_flags)
+{
+ struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+ struct bpf_dtab_netdev *dev, *old_dev;
+ u32 ifindex = *(u32 *)value;
+ u32 idx = *(u32 *)key;
+ unsigned long flags;
+
+ if (unlikely(map_flags > BPF_EXIST || !ifindex))
+ return -EINVAL;
+
+ old_dev = __dev_map_hash_lookup_elem(map, idx);
+ if (old_dev && (map_flags & BPF_NOEXIST))
+ return -EEXIST;
+
+ dev = __dev_map_alloc_node(net, dtab, ifindex, idx);
+ if (IS_ERR(dev))
+ return PTR_ERR(dev);
+
+ spin_lock_irqsave(&dtab->index_lock, flags);
+
+ if (old_dev) {
+ hlist_del_rcu(&old_dev->index_hlist);
+ } else {
+ if (dtab->items >= dtab->map.max_entries) {
+ spin_unlock_irqrestore(&dtab->index_lock, flags);
+ call_rcu(&dev->rcu, __dev_map_entry_free);
+ return -E2BIG;
+ }
+ dtab->items++;
+ }
+
+ hlist_add_head_rcu(&dev->index_hlist,
+ dev_map_index_hash(dtab, idx));
+ spin_unlock_irqrestore(&dtab->index_lock, flags);
+
+ if (old_dev)
+ call_rcu(&old_dev->rcu, __dev_map_entry_free);
+
+ return 0;
+}
+
+static int dev_map_hash_update_elem(struct bpf_map *map, void *key, void *value,
+ u64 map_flags)
+{
+ return __dev_map_hash_update_elem(current->nsproxy->net_ns,
+ map, key, value, map_flags);
+}
+
const struct bpf_map_ops dev_map_ops = {
.map_alloc = dev_map_alloc,
.map_free = dev_map_free,
.map_check_btf = map_check_no_btf,
};
+const struct bpf_map_ops dev_map_hash_ops = {
+ .map_alloc = dev_map_alloc,
+ .map_free = dev_map_free,
+ .map_get_next_key = dev_map_hash_get_next_key,
+ .map_lookup_elem = dev_map_hash_lookup_elem,
+ .map_update_elem = dev_map_hash_update_elem,
+ .map_delete_elem = dev_map_hash_delete_elem,
+ .map_check_btf = map_check_no_btf,
+};
+
static int dev_map_notification(struct notifier_block *notifier,
ulong event, void *ptr)
{
projects / users / hch / configfs.git / commitdiff