| // SPDX-License-Identifier: GPL-2.0-only |
| /* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io |
| */ |
| |
| /* Devmaps primary use is as a backend map for XDP BPF helper call |
| * bpf_redirect_map(). Because XDP is mostly concerned with performance we |
| * spent some effort to ensure the datapath with redirect maps does not use |
| * any locking. This is a quick note on the details. |
| * |
| * We have three possible paths to get into the devmap control plane bpf |
| * syscalls, bpf programs, and driver side xmit/flush operations. A bpf syscall |
| * will invoke an update, delete, or lookup operation. To ensure updates and |
| * deletes appear atomic from the datapath side xchg() is used to modify the |
| * netdev_map array. Then because the datapath does a lookup into the netdev_map |
| * array (read-only) from an RCU critical section we use call_rcu() to wait for |
| * an rcu grace period before free'ing the old data structures. This ensures the |
| * datapath always has a valid copy. However, the datapath does a "flush" |
| * operation that pushes any pending packets in the driver outside the RCU |
| * critical section. Each bpf_dtab_netdev tracks these pending operations using |
| * a per-cpu flush list. The bpf_dtab_netdev object will not be destroyed until |
| * this list is empty, indicating outstanding flush operations have completed. |
| * |
| * BPF syscalls may race with BPF program calls on any of the update, delete |
| * or lookup operations. As noted above the xchg() operation also keep the |
| * netdev_map consistent in this case. From the devmap side BPF programs |
| * calling into these operations are the same as multiple user space threads |
| * making system calls. |
| * |
| * Finally, any of the above may race with a netdev_unregister notifier. The |
| * unregister notifier must search for net devices in the map structure that |
| * contain a reference to the net device and remove them. This is a two step |
| * process (a) dereference the bpf_dtab_netdev object in netdev_map and (b) |
| * check to see if the ifindex is the same as the net_device being removed. |
| * When removing the dev a cmpxchg() is used to ensure the correct dev is |
| * removed, in the case of a concurrent update or delete operation it is |
| * possible that the initially referenced dev is no longer in the map. As the |
| * 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> |
| #include <linux/filter.h> |
| #include <trace/events/xdp.h> |
| #include <linux/btf_ids.h> |
| |
| #define DEV_CREATE_FLAG_MASK \ |
| (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY) |
| |
| struct xdp_dev_bulk_queue { |
| struct xdp_frame *q[DEV_MAP_BULK_SIZE]; |
| struct list_head flush_node; |
| struct net_device *dev; |
| struct net_device *dev_rx; |
| struct bpf_prog *xdp_prog; |
| unsigned int count; |
| }; |
| |
| 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 bpf_prog *xdp_prog; |
| struct rcu_head rcu; |
| unsigned int idx; |
| struct bpf_devmap_val val; |
| }; |
| |
| struct bpf_dtab { |
| struct bpf_map map; |
| struct bpf_dtab_netdev __rcu **netdev_map; /* DEVMAP type only */ |
| 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_PER_CPU(struct list_head, dev_flush_list); |
| static DEFINE_SPINLOCK(dev_map_lock); |
| static LIST_HEAD(dev_map_list); |
| |
| static struct hlist_head *dev_map_create_hash(unsigned int entries, |
| int numa_node) |
| { |
| int i; |
| struct hlist_head *hash; |
| |
| hash = bpf_map_area_alloc((u64) entries * sizeof(*hash), numa_node); |
| if (hash != NULL) |
| for (i = 0; i < entries; i++) |
| INIT_HLIST_HEAD(&hash[i]); |
| |
| return hash; |
| } |
| |
| 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)]; |
| } |
| |
| static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr) |
| { |
| u32 valsize = attr->value_size; |
| |
| /* check sanity of attributes. 2 value sizes supported: |
| * 4 bytes: ifindex |
| * 8 bytes: ifindex + prog fd |
| */ |
| if (attr->max_entries == 0 || attr->key_size != 4 || |
| (valsize != offsetofend(struct bpf_devmap_val, ifindex) && |
| valsize != offsetofend(struct bpf_devmap_val, bpf_prog.fd)) || |
| attr->map_flags & ~DEV_CREATE_FLAG_MASK) |
| return -EINVAL; |
| |
| /* Lookup returns a pointer straight to dev->ifindex, so make sure the |
| * verifier prevents writes from the BPF side |
| */ |
| attr->map_flags |= BPF_F_RDONLY_PROG; |
| |
| |
| bpf_map_init_from_attr(&dtab->map, attr); |
| |
| 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; |
| } |
| |
| if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) { |
| dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets, |
| dtab->map.numa_node); |
| if (!dtab->dev_index_head) |
| return -ENOMEM; |
| |
| spin_lock_init(&dtab->index_lock); |
| } else { |
| dtab->netdev_map = bpf_map_area_alloc((u64) dtab->map.max_entries * |
| sizeof(struct bpf_dtab_netdev *), |
| dtab->map.numa_node); |
| if (!dtab->netdev_map) |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| static struct bpf_map *dev_map_alloc(union bpf_attr *attr) |
| { |
| struct bpf_dtab *dtab; |
| int err; |
| |
| if (!capable(CAP_NET_ADMIN)) |
| return ERR_PTR(-EPERM); |
| |
| dtab = kzalloc(sizeof(*dtab), GFP_USER | __GFP_ACCOUNT); |
| if (!dtab) |
| return ERR_PTR(-ENOMEM); |
| |
| err = dev_map_init_map(dtab, attr); |
| if (err) { |
| kfree(dtab); |
| return ERR_PTR(err); |
| } |
| |
| spin_lock(&dev_map_lock); |
| list_add_tail_rcu(&dtab->list, &dev_map_list); |
| spin_unlock(&dev_map_lock); |
| |
| return &dtab->map; |
| } |
| |
| static void dev_map_free(struct bpf_map *map) |
| { |
| struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); |
| int i; |
| |
| /* At this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, |
| * so the programs (can be more than one that used this map) were |
| * disconnected from events. The following synchronize_rcu() guarantees |
| * both rcu read critical sections complete and waits for |
| * preempt-disable regions (NAPI being the relevant context here) so we |
| * are certain there will be no further reads against the netdev_map and |
| * all flush operations are complete. Flush operations can only be done |
| * from NAPI context for this reason. |
| */ |
| |
| spin_lock(&dev_map_lock); |
| list_del_rcu(&dtab->list); |
| spin_unlock(&dev_map_lock); |
| |
| bpf_clear_redirect_map(map); |
| synchronize_rcu(); |
| |
| /* Make sure prior __dev_map_entry_free() have completed. */ |
| rcu_barrier(); |
| |
| if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) { |
| 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) { |
| hlist_del_rcu(&dev->index_hlist); |
| if (dev->xdp_prog) |
| bpf_prog_put(dev->xdp_prog); |
| dev_put(dev->dev); |
| kfree(dev); |
| } |
| } |
| |
| bpf_map_area_free(dtab->dev_index_head); |
| } else { |
| for (i = 0; i < dtab->map.max_entries; i++) { |
| struct bpf_dtab_netdev *dev; |
| |
| dev = rcu_dereference_raw(dtab->netdev_map[i]); |
| if (!dev) |
| continue; |
| |
| if (dev->xdp_prog) |
| bpf_prog_put(dev->xdp_prog); |
| dev_put(dev->dev); |
| kfree(dev); |
| } |
| |
| bpf_map_area_free(dtab->netdev_map); |
| } |
| |
| kfree(dtab); |
| } |
| |
| static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) |
| { |
| struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); |
| u32 index = key ? *(u32 *)key : U32_MAX; |
| u32 *next = next_key; |
| |
| if (index >= dtab->map.max_entries) { |
| *next = 0; |
| return 0; |
| } |
| |
| if (index == dtab->map.max_entries - 1) |
| return -ENOENT; |
| *next = index + 1; |
| return 0; |
| } |
| |
| /* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or |
| * by local_bh_disable() (from XDP calls inside NAPI). The |
| * rcu_read_lock_bh_held() below makes lockdep accept both. |
| */ |
| static void *__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, |
| lockdep_is_held(&dtab->index_lock)) |
| 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 dev_map_bpf_prog_run(struct bpf_prog *xdp_prog, |
| struct xdp_frame **frames, int n, |
| struct net_device *dev) |
| { |
| struct xdp_txq_info txq = { .dev = dev }; |
| struct xdp_buff xdp; |
| int i, nframes = 0; |
| |
| for (i = 0; i < n; i++) { |
| struct xdp_frame *xdpf = frames[i]; |
| u32 act; |
| int err; |
| |
| xdp_convert_frame_to_buff(xdpf, &xdp); |
| xdp.txq = &txq; |
| |
| act = bpf_prog_run_xdp(xdp_prog, &xdp); |
| switch (act) { |
| case XDP_PASS: |
| err = xdp_update_frame_from_buff(&xdp, xdpf); |
| if (unlikely(err < 0)) |
| xdp_return_frame_rx_napi(xdpf); |
| else |
| frames[nframes++] = xdpf; |
| break; |
| default: |
| bpf_warn_invalid_xdp_action(NULL, xdp_prog, act); |
| fallthrough; |
| case XDP_ABORTED: |
| trace_xdp_exception(dev, xdp_prog, act); |
| fallthrough; |
| case XDP_DROP: |
| xdp_return_frame_rx_napi(xdpf); |
| break; |
| } |
| } |
| return nframes; /* sent frames count */ |
| } |
| |
| static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) |
| { |
| struct net_device *dev = bq->dev; |
| unsigned int cnt = bq->count; |
| int sent = 0, err = 0; |
| int to_send = cnt; |
| int i; |
| |
| if (unlikely(!cnt)) |
| return; |
| |
| for (i = 0; i < cnt; i++) { |
| struct xdp_frame *xdpf = bq->q[i]; |
| |
| prefetch(xdpf); |
| } |
| |
| if (bq->xdp_prog) { |
| to_send = dev_map_bpf_prog_run(bq->xdp_prog, bq->q, cnt, dev); |
| if (!to_send) |
| goto out; |
| } |
| |
| sent = dev->netdev_ops->ndo_xdp_xmit(dev, to_send, bq->q, flags); |
| if (sent < 0) { |
| /* If ndo_xdp_xmit fails with an errno, no frames have |
| * been xmit'ed. |
| */ |
| err = sent; |
| sent = 0; |
| } |
| |
| /* If not all frames have been transmitted, it is our |
| * responsibility to free them |
| */ |
| for (i = sent; unlikely(i < to_send); i++) |
| xdp_return_frame_rx_napi(bq->q[i]); |
| |
| out: |
| bq->count = 0; |
| trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, cnt - sent, err); |
| } |
| |
| /* __dev_flush is called from xdp_do_flush() which _must_ be signalled from the |
| * driver before returning from its napi->poll() routine. See the comment above |
| * xdp_do_flush() in filter.c. |
| */ |
| void __dev_flush(void) |
| { |
| struct list_head *flush_list = this_cpu_ptr(&dev_flush_list); |
| struct xdp_dev_bulk_queue *bq, *tmp; |
| |
| list_for_each_entry_safe(bq, tmp, flush_list, flush_node) { |
| bq_xmit_all(bq, XDP_XMIT_FLUSH); |
| bq->dev_rx = NULL; |
| bq->xdp_prog = NULL; |
| __list_del_clearprev(&bq->flush_node); |
| } |
| } |
| |
| /* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or |
| * by local_bh_disable() (from XDP calls inside NAPI). The |
| * rcu_read_lock_bh_held() below makes lockdep accept both. |
| */ |
| static void *__dev_map_lookup_elem(struct bpf_map *map, u32 key) |
| { |
| struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); |
| struct bpf_dtab_netdev *obj; |
| |
| if (key >= map->max_entries) |
| return NULL; |
| |
| obj = rcu_dereference_check(dtab->netdev_map[key], |
| rcu_read_lock_bh_held()); |
| return obj; |
| } |
| |
| /* Runs in NAPI, i.e., softirq under local_bh_disable(). Thus, safe percpu |
| * variable access, and map elements stick around. See comment above |
| * xdp_do_flush() in filter.c. |
| */ |
| static void bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf, |
| struct net_device *dev_rx, struct bpf_prog *xdp_prog) |
| { |
| struct list_head *flush_list = this_cpu_ptr(&dev_flush_list); |
| struct xdp_dev_bulk_queue *bq = this_cpu_ptr(dev->xdp_bulkq); |
| |
| if (unlikely(bq->count == DEV_MAP_BULK_SIZE)) |
| bq_xmit_all(bq, 0); |
| |
| /* Ingress dev_rx will be the same for all xdp_frame's in |
| * bulk_queue, because bq stored per-CPU and must be flushed |
| * from net_device drivers NAPI func end. |
| * |
| * Do the same with xdp_prog and flush_list since these fields |
| * are only ever modified together. |
| */ |
| if (!bq->dev_rx) { |
| bq->dev_rx = dev_rx; |
| bq->xdp_prog = xdp_prog; |
| list_add(&bq->flush_node, flush_list); |
| } |
| |
| bq->q[bq->count++] = xdpf; |
| } |
| |
| static inline int __xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf, |
| struct net_device *dev_rx, |
| struct bpf_prog *xdp_prog) |
| { |
| int err; |
| |
| if (!dev->netdev_ops->ndo_xdp_xmit) |
| return -EOPNOTSUPP; |
| |
| err = xdp_ok_fwd_dev(dev, xdpf->len); |
| 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 || |
| !obj->dev->netdev_ops->ndo_xdp_xmit) |
| return false; |
| |
| if (xdp_ok_fwd_dev(obj->dev, xdpf->len)) |
| 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); |
| 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_ATOMIC | __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); |
| |
| 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, u32 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, u32 ifindex, u64 flags) |
| { |
| return __bpf_xdp_redirect_map(map, ifindex, flags, |
| BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS, |
| __dev_map_hash_lookup_elem); |
| } |
| |
| 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_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_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); |
| } |
| } |
| 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); |