1166 lines
30 KiB
C
1166 lines
30 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
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*/
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/* Devmaps primary use is as a backend map for XDP BPF helper call
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* bpf_redirect_map(). Because XDP is mostly concerned with performance we
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* spent some effort to ensure the datapath with redirect maps does not use
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* any locking. This is a quick note on the details.
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*
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* We have three possible paths to get into the devmap control plane bpf
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* syscalls, bpf programs, and driver side xmit/flush operations. A bpf syscall
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* will invoke an update, delete, or lookup operation. To ensure updates and
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* deletes appear atomic from the datapath side xchg() is used to modify the
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* netdev_map array. Then because the datapath does a lookup into the netdev_map
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* array (read-only) from an RCU critical section we use call_rcu() to wait for
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* an rcu grace period before free'ing the old data structures. This ensures the
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* datapath always has a valid copy. However, the datapath does a "flush"
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* operation that pushes any pending packets in the driver outside the RCU
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* critical section. Each bpf_dtab_netdev tracks these pending operations using
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* a per-cpu flush list. The bpf_dtab_netdev object will not be destroyed until
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* this list is empty, indicating outstanding flush operations have completed.
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*
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* BPF syscalls may race with BPF program calls on any of the update, delete
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* or lookup operations. As noted above the xchg() operation also keep the
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* netdev_map consistent in this case. From the devmap side BPF programs
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* calling into these operations are the same as multiple user space threads
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* making system calls.
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*
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* Finally, any of the above may race with a netdev_unregister notifier. The
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* unregister notifier must search for net devices in the map structure that
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* contain a reference to the net device and remove them. This is a two step
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* process (a) dereference the bpf_dtab_netdev object in netdev_map and (b)
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* check to see if the ifindex is the same as the net_device being removed.
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* When removing the dev a cmpxchg() is used to ensure the correct dev is
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* removed, in the case of a concurrent update or delete operation it is
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* possible that the initially referenced dev is no longer in the map. As the
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* notifier hook walks the map we know that new dev references can not be
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* added by the user because core infrastructure ensures dev_get_by_index()
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* calls will fail at this point.
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*
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* The devmap_hash type is a map type which interprets keys as ifindexes and
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* indexes these using a hashmap. This allows maps that use ifindex as key to be
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* densely packed instead of having holes in the lookup array for unused
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* ifindexes. The setup and packet enqueue/send code is shared between the two
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* types of devmap; only the lookup and insertion is different.
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*/
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#include <linux/bpf.h>
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#include <net/xdp.h>
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#include <linux/filter.h>
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#include <trace/events/xdp.h>
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#include <linux/btf_ids.h>
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#define DEV_CREATE_FLAG_MASK \
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(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
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struct xdp_dev_bulk_queue {
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struct xdp_frame *q[DEV_MAP_BULK_SIZE];
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struct list_head flush_node;
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struct net_device *dev;
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struct net_device *dev_rx;
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struct bpf_prog *xdp_prog;
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unsigned int count;
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};
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struct bpf_dtab_netdev {
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struct net_device *dev; /* must be first member, due to tracepoint */
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struct hlist_node index_hlist;
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struct bpf_dtab *dtab;
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struct bpf_prog *xdp_prog;
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struct rcu_head rcu;
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unsigned int idx;
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struct bpf_devmap_val val;
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};
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struct bpf_dtab {
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struct bpf_map map;
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struct bpf_dtab_netdev __rcu **netdev_map; /* DEVMAP type only */
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struct list_head list;
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/* these are only used for DEVMAP_HASH type maps */
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struct hlist_head *dev_index_head;
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spinlock_t index_lock;
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unsigned int items;
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u32 n_buckets;
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};
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static DEFINE_PER_CPU(struct list_head, dev_flush_list);
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static DEFINE_SPINLOCK(dev_map_lock);
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static LIST_HEAD(dev_map_list);
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static struct hlist_head *dev_map_create_hash(unsigned int entries,
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int numa_node)
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{
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int i;
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struct hlist_head *hash;
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hash = bpf_map_area_alloc((u64) entries * sizeof(*hash), numa_node);
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if (hash != NULL)
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for (i = 0; i < entries; i++)
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INIT_HLIST_HEAD(&hash[i]);
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return hash;
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}
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static inline struct hlist_head *dev_map_index_hash(struct bpf_dtab *dtab,
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int idx)
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{
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return &dtab->dev_index_head[idx & (dtab->n_buckets - 1)];
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}
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static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
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{
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u32 valsize = attr->value_size;
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/* check sanity of attributes. 2 value sizes supported:
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* 4 bytes: ifindex
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* 8 bytes: ifindex + prog fd
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*/
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if (attr->max_entries == 0 || attr->key_size != 4 ||
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(valsize != offsetofend(struct bpf_devmap_val, ifindex) &&
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valsize != offsetofend(struct bpf_devmap_val, bpf_prog.fd)) ||
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attr->map_flags & ~DEV_CREATE_FLAG_MASK)
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return -EINVAL;
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/* Lookup returns a pointer straight to dev->ifindex, so make sure the
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* verifier prevents writes from the BPF side
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*/
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attr->map_flags |= BPF_F_RDONLY_PROG;
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bpf_map_init_from_attr(&dtab->map, attr);
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if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
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dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
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if (!dtab->n_buckets) /* Overflow check */
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return -EINVAL;
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}
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if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
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dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets,
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dtab->map.numa_node);
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if (!dtab->dev_index_head)
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return -ENOMEM;
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spin_lock_init(&dtab->index_lock);
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} else {
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dtab->netdev_map = bpf_map_area_alloc((u64) dtab->map.max_entries *
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sizeof(struct bpf_dtab_netdev *),
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dtab->map.numa_node);
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if (!dtab->netdev_map)
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return -ENOMEM;
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}
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return 0;
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}
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static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
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{
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struct bpf_dtab *dtab;
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int err;
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if (!capable(CAP_NET_ADMIN))
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return ERR_PTR(-EPERM);
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dtab = bpf_map_area_alloc(sizeof(*dtab), NUMA_NO_NODE);
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if (!dtab)
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return ERR_PTR(-ENOMEM);
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err = dev_map_init_map(dtab, attr);
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if (err) {
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bpf_map_area_free(dtab);
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return ERR_PTR(err);
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}
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spin_lock(&dev_map_lock);
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list_add_tail_rcu(&dtab->list, &dev_map_list);
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spin_unlock(&dev_map_lock);
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return &dtab->map;
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}
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static void dev_map_free(struct bpf_map *map)
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{
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struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
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int i;
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/* At this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
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* so the programs (can be more than one that used this map) were
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* disconnected from events. The following synchronize_rcu() guarantees
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* both rcu read critical sections complete and waits for
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* preempt-disable regions (NAPI being the relevant context here) so we
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* are certain there will be no further reads against the netdev_map and
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* all flush operations are complete. Flush operations can only be done
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* from NAPI context for this reason.
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*/
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spin_lock(&dev_map_lock);
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list_del_rcu(&dtab->list);
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spin_unlock(&dev_map_lock);
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bpf_clear_redirect_map(map);
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synchronize_rcu();
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/* Make sure prior __dev_map_entry_free() have completed. */
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rcu_barrier();
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if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
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for (i = 0; i < dtab->n_buckets; i++) {
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struct bpf_dtab_netdev *dev;
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struct hlist_head *head;
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struct hlist_node *next;
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head = dev_map_index_hash(dtab, i);
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hlist_for_each_entry_safe(dev, next, head, index_hlist) {
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hlist_del_rcu(&dev->index_hlist);
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if (dev->xdp_prog)
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bpf_prog_put(dev->xdp_prog);
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dev_put(dev->dev);
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kfree(dev);
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}
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}
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bpf_map_area_free(dtab->dev_index_head);
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} else {
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for (i = 0; i < dtab->map.max_entries; i++) {
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struct bpf_dtab_netdev *dev;
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dev = rcu_dereference_raw(dtab->netdev_map[i]);
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if (!dev)
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continue;
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if (dev->xdp_prog)
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bpf_prog_put(dev->xdp_prog);
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dev_put(dev->dev);
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kfree(dev);
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}
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bpf_map_area_free(dtab->netdev_map);
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}
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bpf_map_area_free(dtab);
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}
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static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
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{
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struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
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u32 index = key ? *(u32 *)key : U32_MAX;
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u32 *next = next_key;
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if (index >= dtab->map.max_entries) {
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*next = 0;
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return 0;
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}
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if (index == dtab->map.max_entries - 1)
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return -ENOENT;
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*next = index + 1;
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return 0;
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}
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/* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or
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* by local_bh_disable() (from XDP calls inside NAPI). The
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* rcu_read_lock_bh_held() below makes lockdep accept both.
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*/
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static void *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key)
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{
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struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
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struct hlist_head *head = dev_map_index_hash(dtab, key);
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struct bpf_dtab_netdev *dev;
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hlist_for_each_entry_rcu(dev, head, index_hlist,
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lockdep_is_held(&dtab->index_lock))
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if (dev->idx == key)
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return dev;
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return NULL;
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}
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static int dev_map_hash_get_next_key(struct bpf_map *map, void *key,
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void *next_key)
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{
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struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
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u32 idx, *next = next_key;
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struct bpf_dtab_netdev *dev, *next_dev;
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struct hlist_head *head;
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int i = 0;
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if (!key)
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goto find_first;
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idx = *(u32 *)key;
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dev = __dev_map_hash_lookup_elem(map, idx);
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if (!dev)
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goto find_first;
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next_dev = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&dev->index_hlist)),
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struct bpf_dtab_netdev, index_hlist);
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if (next_dev) {
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*next = next_dev->idx;
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return 0;
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}
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i = idx & (dtab->n_buckets - 1);
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i++;
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find_first:
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for (; i < dtab->n_buckets; i++) {
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head = dev_map_index_hash(dtab, i);
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next_dev = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
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struct bpf_dtab_netdev,
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index_hlist);
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if (next_dev) {
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*next = next_dev->idx;
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return 0;
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}
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}
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return -ENOENT;
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}
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static int dev_map_bpf_prog_run(struct bpf_prog *xdp_prog,
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struct xdp_frame **frames, int n,
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struct net_device *dev)
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{
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struct xdp_txq_info txq = { .dev = dev };
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struct xdp_buff xdp;
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int i, nframes = 0;
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for (i = 0; i < n; i++) {
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struct xdp_frame *xdpf = frames[i];
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u32 act;
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int err;
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xdp_convert_frame_to_buff(xdpf, &xdp);
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xdp.txq = &txq;
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act = bpf_prog_run_xdp(xdp_prog, &xdp);
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switch (act) {
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case XDP_PASS:
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err = xdp_update_frame_from_buff(&xdp, xdpf);
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if (unlikely(err < 0))
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xdp_return_frame_rx_napi(xdpf);
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else
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frames[nframes++] = xdpf;
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break;
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default:
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bpf_warn_invalid_xdp_action(NULL, xdp_prog, act);
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fallthrough;
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case XDP_ABORTED:
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trace_xdp_exception(dev, xdp_prog, act);
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fallthrough;
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case XDP_DROP:
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xdp_return_frame_rx_napi(xdpf);
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break;
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}
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}
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return nframes; /* sent frames count */
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}
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static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags)
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{
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struct net_device *dev = bq->dev;
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unsigned int cnt = bq->count;
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int sent = 0, err = 0;
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int to_send = cnt;
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int i;
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if (unlikely(!cnt))
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return;
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for (i = 0; i < cnt; i++) {
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struct xdp_frame *xdpf = bq->q[i];
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prefetch(xdpf);
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}
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if (bq->xdp_prog) {
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to_send = dev_map_bpf_prog_run(bq->xdp_prog, bq->q, cnt, dev);
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if (!to_send)
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goto out;
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}
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sent = dev->netdev_ops->ndo_xdp_xmit(dev, to_send, bq->q, flags);
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if (sent < 0) {
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/* If ndo_xdp_xmit fails with an errno, no frames have
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* been xmit'ed.
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*/
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err = sent;
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sent = 0;
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}
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/* If not all frames have been transmitted, it is our
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* responsibility to free them
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*/
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for (i = sent; unlikely(i < to_send); i++)
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xdp_return_frame_rx_napi(bq->q[i]);
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out:
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bq->count = 0;
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trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, cnt - sent, err);
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}
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/* __dev_flush is called from xdp_do_flush() which _must_ be signalled from the
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* driver before returning from its napi->poll() routine. See the comment above
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* xdp_do_flush() in filter.c.
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*/
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void __dev_flush(void)
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{
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struct list_head *flush_list = this_cpu_ptr(&dev_flush_list);
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struct xdp_dev_bulk_queue *bq, *tmp;
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list_for_each_entry_safe(bq, tmp, flush_list, flush_node) {
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bq_xmit_all(bq, XDP_XMIT_FLUSH);
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bq->dev_rx = NULL;
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bq->xdp_prog = NULL;
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__list_del_clearprev(&bq->flush_node);
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}
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}
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/* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or
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* by local_bh_disable() (from XDP calls inside NAPI). The
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* rcu_read_lock_bh_held() below makes lockdep accept both.
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*/
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static void *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
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{
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struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
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struct bpf_dtab_netdev *obj;
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if (key >= map->max_entries)
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return NULL;
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obj = rcu_dereference_check(dtab->netdev_map[key],
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rcu_read_lock_bh_held());
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return obj;
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}
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/* Runs in NAPI, i.e., softirq under local_bh_disable(). Thus, safe percpu
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* variable access, and map elements stick around. See comment above
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* xdp_do_flush() in filter.c.
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*/
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static void bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
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struct net_device *dev_rx, struct bpf_prog *xdp_prog)
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{
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struct list_head *flush_list = this_cpu_ptr(&dev_flush_list);
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struct xdp_dev_bulk_queue *bq = this_cpu_ptr(dev->xdp_bulkq);
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if (unlikely(bq->count == DEV_MAP_BULK_SIZE))
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bq_xmit_all(bq, 0);
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/* Ingress dev_rx will be the same for all xdp_frame's in
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* bulk_queue, because bq stored per-CPU and must be flushed
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* from net_device drivers NAPI func end.
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*
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* Do the same with xdp_prog and flush_list since these fields
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* are only ever modified together.
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*/
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if (!bq->dev_rx) {
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bq->dev_rx = dev_rx;
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bq->xdp_prog = xdp_prog;
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list_add(&bq->flush_node, flush_list);
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}
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bq->q[bq->count++] = xdpf;
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}
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static inline int __xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
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struct net_device *dev_rx,
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struct bpf_prog *xdp_prog)
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{
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int err;
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|
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if (!(dev->xdp_features & NETDEV_XDP_ACT_NDO_XMIT))
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return -EOPNOTSUPP;
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|
|
if (unlikely(!(dev->xdp_features & NETDEV_XDP_ACT_NDO_XMIT_SG) &&
|
|
xdp_frame_has_frags(xdpf)))
|
|
return -EOPNOTSUPP;
|
|
|
|
err = xdp_ok_fwd_dev(dev, xdp_get_frame_len(xdpf));
|
|
if (unlikely(err))
|
|
return err;
|
|
|
|
bq_enqueue(dev, xdpf, dev_rx, xdp_prog);
|
|
return 0;
|
|
}
|
|
|
|
static u32 dev_map_bpf_prog_run_skb(struct sk_buff *skb, struct bpf_dtab_netdev *dst)
|
|
{
|
|
struct xdp_txq_info txq = { .dev = dst->dev };
|
|
struct xdp_buff xdp;
|
|
u32 act;
|
|
|
|
if (!dst->xdp_prog)
|
|
return XDP_PASS;
|
|
|
|
__skb_pull(skb, skb->mac_len);
|
|
xdp.txq = &txq;
|
|
|
|
act = bpf_prog_run_generic_xdp(skb, &xdp, dst->xdp_prog);
|
|
switch (act) {
|
|
case XDP_PASS:
|
|
__skb_push(skb, skb->mac_len);
|
|
break;
|
|
default:
|
|
bpf_warn_invalid_xdp_action(NULL, dst->xdp_prog, act);
|
|
fallthrough;
|
|
case XDP_ABORTED:
|
|
trace_xdp_exception(dst->dev, dst->xdp_prog, act);
|
|
fallthrough;
|
|
case XDP_DROP:
|
|
kfree_skb(skb);
|
|
break;
|
|
}
|
|
|
|
return act;
|
|
}
|
|
|
|
int dev_xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
|
|
struct net_device *dev_rx)
|
|
{
|
|
return __xdp_enqueue(dev, xdpf, dev_rx, NULL);
|
|
}
|
|
|
|
int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_frame *xdpf,
|
|
struct net_device *dev_rx)
|
|
{
|
|
struct net_device *dev = dst->dev;
|
|
|
|
return __xdp_enqueue(dev, xdpf, dev_rx, dst->xdp_prog);
|
|
}
|
|
|
|
static bool is_valid_dst(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf)
|
|
{
|
|
if (!obj)
|
|
return false;
|
|
|
|
if (!(obj->dev->xdp_features & NETDEV_XDP_ACT_NDO_XMIT))
|
|
return false;
|
|
|
|
if (unlikely(!(obj->dev->xdp_features & NETDEV_XDP_ACT_NDO_XMIT_SG) &&
|
|
xdp_frame_has_frags(xdpf)))
|
|
return false;
|
|
|
|
if (xdp_ok_fwd_dev(obj->dev, xdp_get_frame_len(xdpf)))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static int dev_map_enqueue_clone(struct bpf_dtab_netdev *obj,
|
|
struct net_device *dev_rx,
|
|
struct xdp_frame *xdpf)
|
|
{
|
|
struct xdp_frame *nxdpf;
|
|
|
|
nxdpf = xdpf_clone(xdpf);
|
|
if (!nxdpf)
|
|
return -ENOMEM;
|
|
|
|
bq_enqueue(obj->dev, nxdpf, dev_rx, obj->xdp_prog);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline bool is_ifindex_excluded(int *excluded, int num_excluded, int ifindex)
|
|
{
|
|
while (num_excluded--) {
|
|
if (ifindex == excluded[num_excluded])
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/* Get ifindex of each upper device. 'indexes' must be able to hold at
|
|
* least MAX_NEST_DEV elements.
|
|
* Returns the number of ifindexes added.
|
|
*/
|
|
static int get_upper_ifindexes(struct net_device *dev, int *indexes)
|
|
{
|
|
struct net_device *upper;
|
|
struct list_head *iter;
|
|
int n = 0;
|
|
|
|
netdev_for_each_upper_dev_rcu(dev, upper, iter) {
|
|
indexes[n++] = upper->ifindex;
|
|
}
|
|
return n;
|
|
}
|
|
|
|
int dev_map_enqueue_multi(struct xdp_frame *xdpf, struct net_device *dev_rx,
|
|
struct bpf_map *map, bool exclude_ingress)
|
|
{
|
|
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
|
|
struct bpf_dtab_netdev *dst, *last_dst = NULL;
|
|
int excluded_devices[1+MAX_NEST_DEV];
|
|
struct hlist_head *head;
|
|
int num_excluded = 0;
|
|
unsigned int i;
|
|
int err;
|
|
|
|
if (exclude_ingress) {
|
|
num_excluded = get_upper_ifindexes(dev_rx, excluded_devices);
|
|
excluded_devices[num_excluded++] = dev_rx->ifindex;
|
|
}
|
|
|
|
if (map->map_type == BPF_MAP_TYPE_DEVMAP) {
|
|
for (i = 0; i < map->max_entries; i++) {
|
|
dst = rcu_dereference_check(dtab->netdev_map[i],
|
|
rcu_read_lock_bh_held());
|
|
if (!is_valid_dst(dst, xdpf))
|
|
continue;
|
|
|
|
if (is_ifindex_excluded(excluded_devices, num_excluded, dst->dev->ifindex))
|
|
continue;
|
|
|
|
/* we only need n-1 clones; last_dst enqueued below */
|
|
if (!last_dst) {
|
|
last_dst = dst;
|
|
continue;
|
|
}
|
|
|
|
err = dev_map_enqueue_clone(last_dst, dev_rx, xdpf);
|
|
if (err)
|
|
return err;
|
|
|
|
last_dst = dst;
|
|
}
|
|
} else { /* BPF_MAP_TYPE_DEVMAP_HASH */
|
|
for (i = 0; i < dtab->n_buckets; i++) {
|
|
head = dev_map_index_hash(dtab, i);
|
|
hlist_for_each_entry_rcu(dst, head, index_hlist,
|
|
lockdep_is_held(&dtab->index_lock)) {
|
|
if (!is_valid_dst(dst, xdpf))
|
|
continue;
|
|
|
|
if (is_ifindex_excluded(excluded_devices, num_excluded,
|
|
dst->dev->ifindex))
|
|
continue;
|
|
|
|
/* we only need n-1 clones; last_dst enqueued below */
|
|
if (!last_dst) {
|
|
last_dst = dst;
|
|
continue;
|
|
}
|
|
|
|
err = dev_map_enqueue_clone(last_dst, dev_rx, xdpf);
|
|
if (err)
|
|
return err;
|
|
|
|
last_dst = dst;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* consume the last copy of the frame */
|
|
if (last_dst)
|
|
bq_enqueue(last_dst->dev, xdpf, dev_rx, last_dst->xdp_prog);
|
|
else
|
|
xdp_return_frame_rx_napi(xdpf); /* dtab is empty */
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
|
|
struct bpf_prog *xdp_prog)
|
|
{
|
|
int err;
|
|
|
|
err = xdp_ok_fwd_dev(dst->dev, skb->len);
|
|
if (unlikely(err))
|
|
return err;
|
|
|
|
/* Redirect has already succeeded semantically at this point, so we just
|
|
* return 0 even if packet is dropped. Helper below takes care of
|
|
* freeing skb.
|
|
*/
|
|
if (dev_map_bpf_prog_run_skb(skb, dst) != XDP_PASS)
|
|
return 0;
|
|
|
|
skb->dev = dst->dev;
|
|
generic_xdp_tx(skb, xdp_prog);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int dev_map_redirect_clone(struct bpf_dtab_netdev *dst,
|
|
struct sk_buff *skb,
|
|
struct bpf_prog *xdp_prog)
|
|
{
|
|
struct sk_buff *nskb;
|
|
int err;
|
|
|
|
nskb = skb_clone(skb, GFP_ATOMIC);
|
|
if (!nskb)
|
|
return -ENOMEM;
|
|
|
|
err = dev_map_generic_redirect(dst, nskb, xdp_prog);
|
|
if (unlikely(err)) {
|
|
consume_skb(nskb);
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
|
|
struct bpf_prog *xdp_prog, struct bpf_map *map,
|
|
bool exclude_ingress)
|
|
{
|
|
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
|
|
struct bpf_dtab_netdev *dst, *last_dst = NULL;
|
|
int excluded_devices[1+MAX_NEST_DEV];
|
|
struct hlist_head *head;
|
|
struct hlist_node *next;
|
|
int num_excluded = 0;
|
|
unsigned int i;
|
|
int err;
|
|
|
|
if (exclude_ingress) {
|
|
num_excluded = get_upper_ifindexes(dev, excluded_devices);
|
|
excluded_devices[num_excluded++] = dev->ifindex;
|
|
}
|
|
|
|
if (map->map_type == BPF_MAP_TYPE_DEVMAP) {
|
|
for (i = 0; i < map->max_entries; i++) {
|
|
dst = rcu_dereference_check(dtab->netdev_map[i],
|
|
rcu_read_lock_bh_held());
|
|
if (!dst)
|
|
continue;
|
|
|
|
if (is_ifindex_excluded(excluded_devices, num_excluded, dst->dev->ifindex))
|
|
continue;
|
|
|
|
/* we only need n-1 clones; last_dst enqueued below */
|
|
if (!last_dst) {
|
|
last_dst = dst;
|
|
continue;
|
|
}
|
|
|
|
err = dev_map_redirect_clone(last_dst, skb, xdp_prog);
|
|
if (err)
|
|
return err;
|
|
|
|
last_dst = dst;
|
|
|
|
}
|
|
} else { /* BPF_MAP_TYPE_DEVMAP_HASH */
|
|
for (i = 0; i < dtab->n_buckets; i++) {
|
|
head = dev_map_index_hash(dtab, i);
|
|
hlist_for_each_entry_safe(dst, next, head, index_hlist) {
|
|
if (!dst)
|
|
continue;
|
|
|
|
if (is_ifindex_excluded(excluded_devices, num_excluded,
|
|
dst->dev->ifindex))
|
|
continue;
|
|
|
|
/* we only need n-1 clones; last_dst enqueued below */
|
|
if (!last_dst) {
|
|
last_dst = dst;
|
|
continue;
|
|
}
|
|
|
|
err = dev_map_redirect_clone(last_dst, skb, xdp_prog);
|
|
if (err)
|
|
return err;
|
|
|
|
last_dst = dst;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* consume the first skb and return */
|
|
if (last_dst)
|
|
return dev_map_generic_redirect(last_dst, skb, xdp_prog);
|
|
|
|
/* dtab is empty */
|
|
consume_skb(skb);
|
|
return 0;
|
|
}
|
|
|
|
static void *dev_map_lookup_elem(struct bpf_map *map, void *key)
|
|
{
|
|
struct bpf_dtab_netdev *obj = __dev_map_lookup_elem(map, *(u32 *)key);
|
|
|
|
return obj ? &obj->val : 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);
|
|
return obj ? &obj->val : NULL;
|
|
}
|
|
|
|
static void __dev_map_entry_free(struct rcu_head *rcu)
|
|
{
|
|
struct bpf_dtab_netdev *dev;
|
|
|
|
dev = container_of(rcu, struct bpf_dtab_netdev, rcu);
|
|
if (dev->xdp_prog)
|
|
bpf_prog_put(dev->xdp_prog);
|
|
dev_put(dev->dev);
|
|
kfree(dev);
|
|
}
|
|
|
|
static int dev_map_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;
|
|
|
|
if (k >= map->max_entries)
|
|
return -EINVAL;
|
|
|
|
old_dev = unrcu_pointer(xchg(&dtab->netdev_map[k], NULL));
|
|
if (old_dev) {
|
|
call_rcu(&old_dev->rcu, __dev_map_entry_free);
|
|
atomic_dec((atomic_t *)&dtab->items);
|
|
}
|
|
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,
|
|
struct bpf_devmap_val *val,
|
|
unsigned int idx)
|
|
{
|
|
struct bpf_prog *prog = NULL;
|
|
struct bpf_dtab_netdev *dev;
|
|
|
|
dev = bpf_map_kmalloc_node(&dtab->map, sizeof(*dev),
|
|
GFP_NOWAIT | __GFP_NOWARN,
|
|
dtab->map.numa_node);
|
|
if (!dev)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
dev->dev = dev_get_by_index(net, val->ifindex);
|
|
if (!dev->dev)
|
|
goto err_out;
|
|
|
|
if (val->bpf_prog.fd > 0) {
|
|
prog = bpf_prog_get_type_dev(val->bpf_prog.fd,
|
|
BPF_PROG_TYPE_XDP, false);
|
|
if (IS_ERR(prog))
|
|
goto err_put_dev;
|
|
if (prog->expected_attach_type != BPF_XDP_DEVMAP ||
|
|
!bpf_prog_map_compatible(&dtab->map, prog))
|
|
goto err_put_prog;
|
|
}
|
|
|
|
dev->idx = idx;
|
|
dev->dtab = dtab;
|
|
if (prog) {
|
|
dev->xdp_prog = prog;
|
|
dev->val.bpf_prog.id = prog->aux->id;
|
|
} else {
|
|
dev->xdp_prog = NULL;
|
|
dev->val.bpf_prog.id = 0;
|
|
}
|
|
dev->val.ifindex = val->ifindex;
|
|
|
|
return dev;
|
|
err_put_prog:
|
|
bpf_prog_put(prog);
|
|
err_put_dev:
|
|
dev_put(dev->dev);
|
|
err_out:
|
|
kfree(dev);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
static int __dev_map_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;
|
|
struct bpf_devmap_val val = {};
|
|
u32 i = *(u32 *)key;
|
|
|
|
if (unlikely(map_flags > BPF_EXIST))
|
|
return -EINVAL;
|
|
if (unlikely(i >= dtab->map.max_entries))
|
|
return -E2BIG;
|
|
if (unlikely(map_flags == BPF_NOEXIST))
|
|
return -EEXIST;
|
|
|
|
/* already verified value_size <= sizeof val */
|
|
memcpy(&val, value, map->value_size);
|
|
|
|
if (!val.ifindex) {
|
|
dev = NULL;
|
|
/* can not specify fd if ifindex is 0 */
|
|
if (val.bpf_prog.fd > 0)
|
|
return -EINVAL;
|
|
} else {
|
|
dev = __dev_map_alloc_node(net, dtab, &val, i);
|
|
if (IS_ERR(dev))
|
|
return PTR_ERR(dev);
|
|
}
|
|
|
|
/* Use call_rcu() here to ensure rcu critical sections have completed
|
|
* Remembering the driver side flush operation will happen before the
|
|
* net device is removed.
|
|
*/
|
|
old_dev = unrcu_pointer(xchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev)));
|
|
if (old_dev)
|
|
call_rcu(&old_dev->rcu, __dev_map_entry_free);
|
|
else
|
|
atomic_inc((atomic_t *)&dtab->items);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int dev_map_update_elem(struct bpf_map *map, void *key, void *value,
|
|
u64 map_flags)
|
|
{
|
|
return __dev_map_update_elem(current->nsproxy->net_ns,
|
|
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;
|
|
struct bpf_devmap_val val = {};
|
|
u32 idx = *(u32 *)key;
|
|
unsigned long flags;
|
|
int err = -EEXIST;
|
|
|
|
/* already verified value_size <= sizeof val */
|
|
memcpy(&val, value, map->value_size);
|
|
|
|
if (unlikely(map_flags > BPF_EXIST || !val.ifindex))
|
|
return -EINVAL;
|
|
|
|
spin_lock_irqsave(&dtab->index_lock, flags);
|
|
|
|
old_dev = __dev_map_hash_lookup_elem(map, idx);
|
|
if (old_dev && (map_flags & BPF_NOEXIST))
|
|
goto out_err;
|
|
|
|
dev = __dev_map_alloc_node(net, dtab, &val, idx);
|
|
if (IS_ERR(dev)) {
|
|
err = PTR_ERR(dev);
|
|
goto out_err;
|
|
}
|
|
|
|
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;
|
|
|
|
out_err:
|
|
spin_unlock_irqrestore(&dtab->index_lock, flags);
|
|
return err;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
static int dev_map_redirect(struct bpf_map *map, u64 ifindex, u64 flags)
|
|
{
|
|
return __bpf_xdp_redirect_map(map, ifindex, flags,
|
|
BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS,
|
|
__dev_map_lookup_elem);
|
|
}
|
|
|
|
static int dev_hash_map_redirect(struct bpf_map *map, u64 ifindex, u64 flags)
|
|
{
|
|
return __bpf_xdp_redirect_map(map, ifindex, flags,
|
|
BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS,
|
|
__dev_map_hash_lookup_elem);
|
|
}
|
|
|
|
static u64 dev_map_mem_usage(const struct bpf_map *map)
|
|
{
|
|
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
|
|
u64 usage = sizeof(struct bpf_dtab);
|
|
|
|
if (map->map_type == BPF_MAP_TYPE_DEVMAP_HASH)
|
|
usage += (u64)dtab->n_buckets * sizeof(struct hlist_head);
|
|
else
|
|
usage += (u64)map->max_entries * sizeof(struct bpf_dtab_netdev *);
|
|
usage += atomic_read((atomic_t *)&dtab->items) *
|
|
(u64)sizeof(struct bpf_dtab_netdev);
|
|
return usage;
|
|
}
|
|
|
|
BTF_ID_LIST_SINGLE(dev_map_btf_ids, struct, bpf_dtab)
|
|
const struct bpf_map_ops dev_map_ops = {
|
|
.map_meta_equal = bpf_map_meta_equal,
|
|
.map_alloc = dev_map_alloc,
|
|
.map_free = dev_map_free,
|
|
.map_get_next_key = dev_map_get_next_key,
|
|
.map_lookup_elem = dev_map_lookup_elem,
|
|
.map_update_elem = dev_map_update_elem,
|
|
.map_delete_elem = dev_map_delete_elem,
|
|
.map_check_btf = map_check_no_btf,
|
|
.map_mem_usage = dev_map_mem_usage,
|
|
.map_btf_id = &dev_map_btf_ids[0],
|
|
.map_redirect = dev_map_redirect,
|
|
};
|
|
|
|
const struct bpf_map_ops dev_map_hash_ops = {
|
|
.map_meta_equal = bpf_map_meta_equal,
|
|
.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,
|
|
.map_mem_usage = dev_map_mem_usage,
|
|
.map_btf_id = &dev_map_btf_ids[0],
|
|
.map_redirect = dev_hash_map_redirect,
|
|
};
|
|
|
|
static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab,
|
|
struct net_device *netdev)
|
|
{
|
|
unsigned long flags;
|
|
u32 i;
|
|
|
|
spin_lock_irqsave(&dtab->index_lock, flags);
|
|
for (i = 0; i < dtab->n_buckets; i++) {
|
|
struct bpf_dtab_netdev *dev;
|
|
struct hlist_head *head;
|
|
struct hlist_node *next;
|
|
|
|
head = dev_map_index_hash(dtab, i);
|
|
|
|
hlist_for_each_entry_safe(dev, next, head, index_hlist) {
|
|
if (netdev != dev->dev)
|
|
continue;
|
|
|
|
dtab->items--;
|
|
hlist_del_rcu(&dev->index_hlist);
|
|
call_rcu(&dev->rcu, __dev_map_entry_free);
|
|
}
|
|
}
|
|
spin_unlock_irqrestore(&dtab->index_lock, flags);
|
|
}
|
|
|
|
static int dev_map_notification(struct notifier_block *notifier,
|
|
ulong event, void *ptr)
|
|
{
|
|
struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
|
|
struct bpf_dtab *dtab;
|
|
int i, cpu;
|
|
|
|
switch (event) {
|
|
case NETDEV_REGISTER:
|
|
if (!netdev->netdev_ops->ndo_xdp_xmit || netdev->xdp_bulkq)
|
|
break;
|
|
|
|
/* will be freed in free_netdev() */
|
|
netdev->xdp_bulkq = alloc_percpu(struct xdp_dev_bulk_queue);
|
|
if (!netdev->xdp_bulkq)
|
|
return NOTIFY_BAD;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
per_cpu_ptr(netdev->xdp_bulkq, cpu)->dev = netdev;
|
|
break;
|
|
case NETDEV_UNREGISTER:
|
|
/* This rcu_read_lock/unlock pair is needed because
|
|
* dev_map_list is an RCU list AND to ensure a delete
|
|
* operation does not free a netdev_map entry while we
|
|
* are comparing it against the netdev being unregistered.
|
|
*/
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(dtab, &dev_map_list, list) {
|
|
if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
|
|
dev_map_hash_remove_netdev(dtab, netdev);
|
|
continue;
|
|
}
|
|
|
|
for (i = 0; i < dtab->map.max_entries; i++) {
|
|
struct bpf_dtab_netdev *dev, *odev;
|
|
|
|
dev = rcu_dereference(dtab->netdev_map[i]);
|
|
if (!dev || netdev != dev->dev)
|
|
continue;
|
|
odev = unrcu_pointer(cmpxchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev), NULL));
|
|
if (dev == odev) {
|
|
call_rcu(&dev->rcu,
|
|
__dev_map_entry_free);
|
|
atomic_dec((atomic_t *)&dtab->items);
|
|
}
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block dev_map_notifier = {
|
|
.notifier_call = dev_map_notification,
|
|
};
|
|
|
|
static int __init dev_map_init(void)
|
|
{
|
|
int cpu;
|
|
|
|
/* Assure tracepoint shadow struct _bpf_dtab_netdev is in sync */
|
|
BUILD_BUG_ON(offsetof(struct bpf_dtab_netdev, dev) !=
|
|
offsetof(struct _bpf_dtab_netdev, dev));
|
|
register_netdevice_notifier(&dev_map_notifier);
|
|
|
|
for_each_possible_cpu(cpu)
|
|
INIT_LIST_HEAD(&per_cpu(dev_flush_list, cpu));
|
|
return 0;
|
|
}
|
|
|
|
subsys_initcall(dev_map_init);
|