From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/kernel/bpf/devmap.c | 710 +++++++++++++++++++++++++++++++++++++++++++----------------
1 files changed, 517 insertions(+), 193 deletions(-)
diff --git a/kernel/kernel/bpf/devmap.c b/kernel/kernel/bpf/devmap.c
index 1defea4..0114982 100644
--- a/kernel/kernel/bpf/devmap.c
+++ b/kernel/kernel/bpf/devmap.c
@@ -1,13 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
*/
/* Devmaps primary use is as a backend map for XDP BPF helper call
@@ -25,9 +17,8 @@
* 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
- * an atomic per-cpu bitmap. The bpf_dtab_netdev object will not be destroyed
- * until all bits are cleared indicating outstanding flush operations have
- * completed.
+ * 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
@@ -46,6 +37,12 @@
* 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>
@@ -55,106 +52,159 @@
#define DEV_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
-#define DEV_MAP_BULK_SIZE 16
-struct xdp_bulk_queue {
+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;
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;
- unsigned int bit;
- struct xdp_bulk_queue __percpu *bulkq;
+ 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 **netdev_map;
- unsigned long __percpu *flush_needed;
+ struct bpf_dtab_netdev **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 u64 dev_map_bitmap_size(const union bpf_attr *attr)
+static struct hlist_head *dev_map_create_hash(unsigned int entries,
+ int numa_node)
{
- return BITS_TO_LONGS((u64) attr->max_entries) * sizeof(unsigned long);
+ 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;
+ u64 cost = 0;
+ int err;
+
+ /* 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;
+ cost += (u64) sizeof(struct hlist_head) * dtab->n_buckets;
+ } else {
+ cost += (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
+ }
+
+ /* if map size is larger than memlock limit, reject it */
+ err = bpf_map_charge_init(&dtab->map.memory, cost);
+ if (err)
+ 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)
+ goto free_charge;
+
+ 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)
+ goto free_charge;
+ }
+
+ return 0;
+
+free_charge:
+ bpf_map_charge_finish(&dtab->map.memory);
+ return -ENOMEM;
}
static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
{
struct bpf_dtab *dtab;
- int err = -EINVAL;
- u64 cost;
+ int err;
if (!capable(CAP_NET_ADMIN))
return ERR_PTR(-EPERM);
-
- /* check sanity of attributes */
- if (attr->max_entries == 0 || attr->key_size != 4 ||
- attr->value_size != 4 || attr->map_flags & ~DEV_CREATE_FLAG_MASK)
- return ERR_PTR(-EINVAL);
dtab = kzalloc(sizeof(*dtab), GFP_USER);
if (!dtab)
return ERR_PTR(-ENOMEM);
- bpf_map_init_from_attr(&dtab->map, attr);
-
- /* make sure page count doesn't overflow */
- cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
- cost += dev_map_bitmap_size(attr) * num_possible_cpus();
- if (cost >= U32_MAX - PAGE_SIZE)
- goto free_dtab;
-
- dtab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
-
- /* if map size is larger than memlock limit, reject it early */
- err = bpf_map_precharge_memlock(dtab->map.pages);
- if (err)
- goto free_dtab;
-
- err = -ENOMEM;
-
- /* A per cpu bitfield with a bit per possible net device */
- dtab->flush_needed = __alloc_percpu_gfp(dev_map_bitmap_size(attr),
- __alignof__(unsigned long),
- GFP_KERNEL | __GFP_NOWARN);
- if (!dtab->flush_needed)
- goto free_dtab;
-
- dtab->netdev_map = bpf_map_area_alloc(dtab->map.max_entries *
- sizeof(struct bpf_dtab_netdev *),
- dtab->map.numa_node);
- if (!dtab->netdev_map)
- goto free_dtab;
+ 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;
-free_dtab:
- free_percpu(dtab->flush_needed);
- kfree(dtab);
- return ERR_PTR(err);
}
static void dev_map_free(struct bpf_map *map)
{
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
- int i, cpu;
+ 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. Wait for outstanding critical sections in
- * these programs to complete. The rcu critical section only guarantees
- * no further reads against netdev_map. It does __not__ ensure pending
- * flush operations (if any) are complete.
+ * 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);
@@ -167,32 +217,41 @@
/* Make sure prior __dev_map_entry_free() have completed. */
rcu_barrier();
- /* To ensure all pending flush operations have completed wait for flush
- * bitmap to indicate all flush_needed bits to be zero on _all_ cpus.
- * Because the above synchronize_rcu() ensures the map is disconnected
- * from the program we can assume no new bits will be set.
- */
- for_each_online_cpu(cpu) {
- unsigned long *bitmap = per_cpu_ptr(dtab->flush_needed, cpu);
+ 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;
- while (!bitmap_empty(bitmap, dtab->map.max_entries))
- cond_resched();
+ 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 = 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);
}
- for (i = 0; i < dtab->map.max_entries; i++) {
- struct bpf_dtab_netdev *dev;
-
- dev = dtab->netdev_map[i];
- if (!dev)
- continue;
-
- free_percpu(dev->bulkq);
- dev_put(dev->dev);
- kfree(dev);
- }
-
- free_percpu(dtab->flush_needed);
- bpf_map_area_free(dtab->netdev_map);
kfree(dtab);
}
@@ -213,24 +272,83 @@
return 0;
}
-void __dev_map_insert_ctx(struct bpf_map *map, u32 bit)
+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);
- unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed);
+ struct hlist_head *head = dev_map_index_hash(dtab, key);
+ struct bpf_dtab_netdev *dev;
- __set_bit(bit, bitmap);
+ 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 bq_xmit_all(struct bpf_dtab_netdev *obj,
- struct xdp_bulk_queue *bq, u32 flags,
- bool in_napi_ctx)
+static int dev_map_hash_get_next_key(struct bpf_map *map, void *key,
+ void *next_key)
{
- struct net_device *dev = obj->dev;
+ 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;
+}
+
+bool dev_map_can_have_prog(struct bpf_map *map)
+{
+ if ((map->map_type == BPF_MAP_TYPE_DEVMAP ||
+ map->map_type == BPF_MAP_TYPE_DEVMAP_HASH) &&
+ map->value_size != offsetofend(struct bpf_devmap_val, ifindex))
+ return true;
+
+ return false;
+}
+
+static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags)
+{
+ struct net_device *dev = bq->dev;
int sent = 0, drops = 0, err = 0;
int i;
if (unlikely(!bq->count))
- return 0;
+ return;
for (i = 0; i < bq->count; i++) {
struct xdp_frame *xdpf = bq->q[i];
@@ -248,10 +366,10 @@
out:
bq->count = 0;
- trace_xdp_devmap_xmit(&obj->dtab->map, obj->bit,
- sent, drops, bq->dev_rx, dev, err);
+ trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, drops, err);
bq->dev_rx = NULL;
- return 0;
+ __list_del_clearprev(&bq->flush_node);
+ return;
error:
/* If ndo_xdp_xmit fails with an errno, no frames have been
* xmit'ed and it's our responsibility to them free all.
@@ -259,46 +377,29 @@
for (i = 0; i < bq->count; i++) {
struct xdp_frame *xdpf = bq->q[i];
- /* RX path under NAPI protection, can return frames faster */
- if (likely(in_napi_ctx))
- xdp_return_frame_rx_napi(xdpf);
- else
- xdp_return_frame(xdpf);
+ xdp_return_frame_rx_napi(xdpf);
drops++;
}
goto out;
}
-/* __dev_map_flush is called from xdp_do_flush_map() which _must_ be signaled
+/* __dev_flush is called from xdp_do_flush() which _must_ be signaled
* from the driver before returning from its napi->poll() routine. The poll()
* routine is called either from busy_poll context or net_rx_action signaled
* from NET_RX_SOFTIRQ. Either way the poll routine must complete before the
- * net device can be torn down. On devmap tear down we ensure the ctx bitmap
- * is zeroed before completing to ensure all flush operations have completed.
+ * net device can be torn down. On devmap tear down we ensure the flush list
+ * is empty before completing to ensure all flush operations have completed.
+ * When drivers update the bpf program they may need to ensure any flush ops
+ * are also complete. Using synchronize_rcu or call_rcu will suffice for this
+ * because both wait for napi context to exit.
*/
-void __dev_map_flush(struct bpf_map *map)
+void __dev_flush(void)
{
- struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
- unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed);
- u32 bit;
+ struct list_head *flush_list = this_cpu_ptr(&dev_flush_list);
+ struct xdp_dev_bulk_queue *bq, *tmp;
- rcu_read_lock();
- for_each_set_bit(bit, bitmap, map->max_entries) {
- struct bpf_dtab_netdev *dev = READ_ONCE(dtab->netdev_map[bit]);
- struct xdp_bulk_queue *bq;
-
- /* This is possible if the dev entry is removed by user space
- * between xdp redirect and flush op.
- */
- if (unlikely(!dev))
- continue;
-
- bq = this_cpu_ptr(dev->bulkq);
- bq_xmit_all(dev, bq, XDP_XMIT_FLUSH, true);
-
- __clear_bit(bit, bitmap);
- }
- rcu_read_unlock();
+ list_for_each_entry_safe(bq, tmp, flush_list, flush_node)
+ bq_xmit_all(bq, XDP_XMIT_FLUSH);
}
/* rcu_read_lock (from syscall and BPF contexts) ensures that if a delete and/or
@@ -320,14 +421,14 @@
/* Runs under RCU-read-side, plus in softirq under NAPI protection.
* Thus, safe percpu variable access.
*/
-static int bq_enqueue(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf,
- struct net_device *dev_rx)
-
+static void bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
+ struct net_device *dev_rx)
{
- struct xdp_bulk_queue *bq = this_cpu_ptr(obj->bulkq);
+ 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(obj, bq, 0, true);
+ 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
@@ -337,13 +438,14 @@
bq->dev_rx = dev_rx;
bq->q[bq->count++] = xdpf;
- return 0;
+
+ if (!bq->flush_node.prev)
+ list_add(&bq->flush_node, flush_list);
}
-int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
- struct net_device *dev_rx)
+static inline int __xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
+ struct net_device *dev_rx)
{
- struct net_device *dev = dst->dev;
struct xdp_frame *xdpf;
int err;
@@ -354,11 +456,59 @@
if (unlikely(err))
return err;
- xdpf = convert_to_xdp_frame(xdp);
+ xdpf = xdp_convert_buff_to_frame(xdp);
if (unlikely(!xdpf))
return -EOVERFLOW;
- return bq_enqueue(dst, xdpf, dev_rx);
+ bq_enqueue(dev, xdpf, dev_rx);
+ return 0;
+}
+
+static struct xdp_buff *dev_map_run_prog(struct net_device *dev,
+ struct xdp_buff *xdp,
+ struct bpf_prog *xdp_prog)
+{
+ struct xdp_txq_info txq = { .dev = dev };
+ u32 act;
+
+ xdp_set_data_meta_invalid(xdp);
+ xdp->txq = &txq;
+
+ act = bpf_prog_run_xdp(xdp_prog, xdp);
+ switch (act) {
+ case XDP_PASS:
+ return xdp;
+ case XDP_DROP:
+ break;
+ default:
+ bpf_warn_invalid_xdp_action(act);
+ fallthrough;
+ case XDP_ABORTED:
+ trace_xdp_exception(dev, xdp_prog, act);
+ break;
+ }
+
+ xdp_return_buff(xdp);
+ return NULL;
+}
+
+int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
+ struct net_device *dev_rx)
+{
+ return __xdp_enqueue(dev, xdp, dev_rx);
+}
+
+int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
+ struct net_device *dev_rx)
+{
+ struct net_device *dev = dst->dev;
+
+ if (dst->xdp_prog) {
+ xdp = dev_map_run_prog(dev, xdp, dst->xdp_prog);
+ if (!xdp)
+ return 0;
+ }
+ return __xdp_enqueue(dev, xdp, dev_rx);
}
int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
@@ -378,29 +528,15 @@
static void *dev_map_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_dtab_netdev *obj = __dev_map_lookup_elem(map, *(u32 *)key);
- struct net_device *dev = obj ? obj->dev : NULL;
- return dev ? &dev->ifindex : NULL;
+ return obj ? &obj->val : NULL;
}
-static void dev_map_flush_old(struct bpf_dtab_netdev *dev)
+static void *dev_map_hash_lookup_elem(struct bpf_map *map, void *key)
{
- if (dev->dev->netdev_ops->ndo_xdp_xmit) {
- struct xdp_bulk_queue *bq;
- unsigned long *bitmap;
-
- int cpu;
-
- rcu_read_lock();
- for_each_online_cpu(cpu) {
- bitmap = per_cpu_ptr(dev->dtab->flush_needed, cpu);
- __clear_bit(dev->bit, bitmap);
-
- bq = per_cpu_ptr(dev->bulkq, cpu);
- bq_xmit_all(dev, bq, XDP_XMIT_FLUSH, false);
- }
- rcu_read_unlock();
- }
+ 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)
@@ -408,8 +544,8 @@
struct bpf_dtab_netdev *dev;
dev = container_of(rcu, struct bpf_dtab_netdev, rcu);
- dev_map_flush_old(dev);
- free_percpu(dev->bulkq);
+ if (dev->xdp_prog)
+ bpf_prog_put(dev->xdp_prog);
dev_put(dev->dev);
kfree(dev);
}
@@ -424,12 +560,11 @@
return -EINVAL;
/* Use call_rcu() here to ensure any rcu critical sections have
- * completed, but this does not guarantee a flush has happened
- * yet. Because driver side rcu_read_lock/unlock only protects the
- * running XDP program. However, for pending flush operations the
- * dev and ctx are stored in another per cpu map. And additionally,
- * the driver tear down ensures all soft irqs are complete before
- * removing the net device in the case of dev_put equals zero.
+ * completed as well as any flush operations because call_rcu
+ * will wait for preempt-disable region to complete, NAPI in this
+ * context. And additionally, the driver tear down ensures all
+ * soft irqs are complete before removing the net device in the
+ * case of dev_put equals zero.
*/
old_dev = xchg(&dtab->netdev_map[k], NULL);
if (old_dev)
@@ -437,15 +572,82 @@
return 0;
}
-static int dev_map_update_elem(struct bpf_map *map, void *key, void *value,
- u64 map_flags)
+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 net *net = current->nsproxy->net_ns;
- gfp_t gfp = GFP_ATOMIC | __GFP_NOWARN;
+ 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 = kmalloc_node(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)
+ 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;
- u32 ifindex = *(u32 *)value;
if (unlikely(map_flags > BPF_EXIST))
return -EINVAL;
@@ -454,29 +656,18 @@
if (unlikely(map_flags == BPF_NOEXIST))
return -EEXIST;
- if (!ifindex) {
+ /* already verified value_size <= sizeof val */
+ memcpy(&val, value, map->value_size);
+
+ if (!val.ifindex) {
dev = NULL;
- } else {
- dev = kmalloc_node(sizeof(*dev), gfp, map->numa_node);
- if (!dev)
- return -ENOMEM;
-
- dev->bulkq = __alloc_percpu_gfp(sizeof(*dev->bulkq),
- sizeof(void *), gfp);
- if (!dev->bulkq) {
- kfree(dev);
- return -ENOMEM;
- }
-
- dev->dev = dev_get_by_index(net, ifindex);
- if (!dev->dev) {
- free_percpu(dev->bulkq);
- kfree(dev);
+ /* can not specify fd if ifindex is 0 */
+ if (val.bpf_prog.fd > 0)
return -EINVAL;
- }
-
- dev->bit = i;
- dev->dtab = dtab;
+ } 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
@@ -490,7 +681,76 @@
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_btf_id;
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,
@@ -498,16 +758,70 @@
.map_update_elem = dev_map_update_elem,
.map_delete_elem = dev_map_delete_elem,
.map_check_btf = map_check_no_btf,
+ .map_btf_name = "bpf_dtab",
+ .map_btf_id = &dev_map_btf_id,
};
+
+static int dev_map_hash_map_btf_id;
+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_name = "bpf_dtab",
+ .map_btf_id = &dev_map_hash_map_btf_id,
+};
+
+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;
+ 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
@@ -516,6 +830,11 @@
*/
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;
@@ -542,10 +861,15 @@
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;
}
--
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