offload.c
16.3 KB
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/*
* Copyright (C) 2017-2018 Netronome Systems, Inc.
*
* This software is licensed under the GNU General License Version 2,
* June 1991 as shown in the file COPYING in the top-level directory of this
* source tree.
*
* THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
* WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
* OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
* THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
*/
#include <linux/bpf.h>
#include <linux/bpf_verifier.h>
#include <linux/bug.h>
#include <linux/kdev_t.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/printk.h>
#include <linux/proc_ns.h>
#include <linux/rhashtable.h>
#include <linux/rtnetlink.h>
#include <linux/rwsem.h>
/* Protects offdevs, members of bpf_offload_netdev and offload members
* of all progs.
* RTNL lock cannot be taken when holding this lock.
*/
static DECLARE_RWSEM(bpf_devs_lock);
struct bpf_offload_dev {
const struct bpf_prog_offload_ops *ops;
struct list_head netdevs;
void *priv;
};
struct bpf_offload_netdev {
struct rhash_head l;
struct net_device *netdev;
struct bpf_offload_dev *offdev;
struct list_head progs;
struct list_head maps;
struct list_head offdev_netdevs;
};
static const struct rhashtable_params offdevs_params = {
.nelem_hint = 4,
.key_len = sizeof(struct net_device *),
.key_offset = offsetof(struct bpf_offload_netdev, netdev),
.head_offset = offsetof(struct bpf_offload_netdev, l),
.automatic_shrinking = true,
};
static struct rhashtable offdevs;
static bool offdevs_inited;
static int bpf_dev_offload_check(struct net_device *netdev)
{
if (!netdev)
return -EINVAL;
if (!netdev->netdev_ops->ndo_bpf)
return -EOPNOTSUPP;
return 0;
}
static struct bpf_offload_netdev *
bpf_offload_find_netdev(struct net_device *netdev)
{
lockdep_assert_held(&bpf_devs_lock);
if (!offdevs_inited)
return NULL;
return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
}
int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
{
struct bpf_offload_netdev *ondev;
struct bpf_prog_offload *offload;
int err;
if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS &&
attr->prog_type != BPF_PROG_TYPE_XDP)
return -EINVAL;
if (attr->prog_flags)
return -EINVAL;
offload = kzalloc(sizeof(*offload), GFP_USER);
if (!offload)
return -ENOMEM;
offload->prog = prog;
offload->netdev = dev_get_by_index(current->nsproxy->net_ns,
attr->prog_ifindex);
err = bpf_dev_offload_check(offload->netdev);
if (err)
goto err_maybe_put;
down_write(&bpf_devs_lock);
ondev = bpf_offload_find_netdev(offload->netdev);
if (!ondev) {
err = -EINVAL;
goto err_unlock;
}
offload->offdev = ondev->offdev;
prog->aux->offload = offload;
list_add_tail(&offload->offloads, &ondev->progs);
dev_put(offload->netdev);
up_write(&bpf_devs_lock);
return 0;
err_unlock:
up_write(&bpf_devs_lock);
err_maybe_put:
if (offload->netdev)
dev_put(offload->netdev);
kfree(offload);
return err;
}
int bpf_prog_offload_verifier_prep(struct bpf_prog *prog)
{
struct bpf_prog_offload *offload;
int ret = -ENODEV;
down_read(&bpf_devs_lock);
offload = prog->aux->offload;
if (offload) {
ret = offload->offdev->ops->prepare(prog);
offload->dev_state = !ret;
}
up_read(&bpf_devs_lock);
return ret;
}
int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
int insn_idx, int prev_insn_idx)
{
struct bpf_prog_offload *offload;
int ret = -ENODEV;
down_read(&bpf_devs_lock);
offload = env->prog->aux->offload;
if (offload)
ret = offload->offdev->ops->insn_hook(env, insn_idx,
prev_insn_idx);
up_read(&bpf_devs_lock);
return ret;
}
int bpf_prog_offload_finalize(struct bpf_verifier_env *env)
{
struct bpf_prog_offload *offload;
int ret = -ENODEV;
down_read(&bpf_devs_lock);
offload = env->prog->aux->offload;
if (offload) {
if (offload->offdev->ops->finalize)
ret = offload->offdev->ops->finalize(env);
else
ret = 0;
}
up_read(&bpf_devs_lock);
return ret;
}
void
bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
struct bpf_insn *insn)
{
const struct bpf_prog_offload_ops *ops;
struct bpf_prog_offload *offload;
int ret = -EOPNOTSUPP;
down_read(&bpf_devs_lock);
offload = env->prog->aux->offload;
if (offload) {
ops = offload->offdev->ops;
if (!offload->opt_failed && ops->replace_insn)
ret = ops->replace_insn(env, off, insn);
offload->opt_failed |= ret;
}
up_read(&bpf_devs_lock);
}
void
bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
{
struct bpf_prog_offload *offload;
int ret = -EOPNOTSUPP;
down_read(&bpf_devs_lock);
offload = env->prog->aux->offload;
if (offload) {
if (!offload->opt_failed && offload->offdev->ops->remove_insns)
ret = offload->offdev->ops->remove_insns(env, off, cnt);
offload->opt_failed |= ret;
}
up_read(&bpf_devs_lock);
}
static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
{
struct bpf_prog_offload *offload = prog->aux->offload;
if (offload->dev_state)
offload->offdev->ops->destroy(prog);
/* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */
bpf_prog_free_id(prog, true);
list_del_init(&offload->offloads);
kfree(offload);
prog->aux->offload = NULL;
}
void bpf_prog_offload_destroy(struct bpf_prog *prog)
{
down_write(&bpf_devs_lock);
if (prog->aux->offload)
__bpf_prog_offload_destroy(prog);
up_write(&bpf_devs_lock);
}
static int bpf_prog_offload_translate(struct bpf_prog *prog)
{
struct bpf_prog_offload *offload;
int ret = -ENODEV;
down_read(&bpf_devs_lock);
offload = prog->aux->offload;
if (offload)
ret = offload->offdev->ops->translate(prog);
up_read(&bpf_devs_lock);
return ret;
}
static unsigned int bpf_prog_warn_on_exec(const void *ctx,
const struct bpf_insn *insn)
{
WARN(1, "attempt to execute device eBPF program on the host!");
return 0;
}
int bpf_prog_offload_compile(struct bpf_prog *prog)
{
prog->bpf_func = bpf_prog_warn_on_exec;
return bpf_prog_offload_translate(prog);
}
struct ns_get_path_bpf_prog_args {
struct bpf_prog *prog;
struct bpf_prog_info *info;
};
static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data)
{
struct ns_get_path_bpf_prog_args *args = private_data;
struct bpf_prog_aux *aux = args->prog->aux;
struct ns_common *ns;
struct net *net;
rtnl_lock();
down_read(&bpf_devs_lock);
if (aux->offload) {
args->info->ifindex = aux->offload->netdev->ifindex;
net = dev_net(aux->offload->netdev);
get_net(net);
ns = &net->ns;
} else {
args->info->ifindex = 0;
ns = NULL;
}
up_read(&bpf_devs_lock);
rtnl_unlock();
return ns;
}
int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
struct bpf_prog *prog)
{
struct ns_get_path_bpf_prog_args args = {
.prog = prog,
.info = info,
};
struct bpf_prog_aux *aux = prog->aux;
struct inode *ns_inode;
struct path ns_path;
char __user *uinsns;
int res;
u32 ulen;
res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
if (res) {
if (!info->ifindex)
return -ENODEV;
return res;
}
down_read(&bpf_devs_lock);
if (!aux->offload) {
up_read(&bpf_devs_lock);
return -ENODEV;
}
ulen = info->jited_prog_len;
info->jited_prog_len = aux->offload->jited_len;
if (info->jited_prog_len & ulen) {
uinsns = u64_to_user_ptr(info->jited_prog_insns);
ulen = min_t(u32, info->jited_prog_len, ulen);
if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {
up_read(&bpf_devs_lock);
return -EFAULT;
}
}
up_read(&bpf_devs_lock);
ns_inode = ns_path.dentry->d_inode;
info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
info->netns_ino = ns_inode->i_ino;
path_put(&ns_path);
return 0;
}
const struct bpf_prog_ops bpf_offload_prog_ops = {
};
static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap,
enum bpf_netdev_command cmd)
{
struct netdev_bpf data = {};
struct net_device *netdev;
ASSERT_RTNL();
data.command = cmd;
data.offmap = offmap;
/* Caller must make sure netdev is valid */
netdev = offmap->netdev;
return netdev->netdev_ops->ndo_bpf(netdev, &data);
}
struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr)
{
struct net *net = current->nsproxy->net_ns;
struct bpf_offload_netdev *ondev;
struct bpf_offloaded_map *offmap;
int err;
if (!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
attr->map_type != BPF_MAP_TYPE_HASH)
return ERR_PTR(-EINVAL);
offmap = kzalloc(sizeof(*offmap), GFP_USER);
if (!offmap)
return ERR_PTR(-ENOMEM);
bpf_map_init_from_attr(&offmap->map, attr);
rtnl_lock();
down_write(&bpf_devs_lock);
offmap->netdev = __dev_get_by_index(net, attr->map_ifindex);
err = bpf_dev_offload_check(offmap->netdev);
if (err)
goto err_unlock;
ondev = bpf_offload_find_netdev(offmap->netdev);
if (!ondev) {
err = -EINVAL;
goto err_unlock;
}
err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC);
if (err)
goto err_unlock;
list_add_tail(&offmap->offloads, &ondev->maps);
up_write(&bpf_devs_lock);
rtnl_unlock();
return &offmap->map;
err_unlock:
up_write(&bpf_devs_lock);
rtnl_unlock();
kfree(offmap);
return ERR_PTR(err);
}
static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap)
{
WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE));
/* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */
bpf_map_free_id(&offmap->map, true);
list_del_init(&offmap->offloads);
offmap->netdev = NULL;
}
void bpf_map_offload_map_free(struct bpf_map *map)
{
struct bpf_offloaded_map *offmap = map_to_offmap(map);
rtnl_lock();
down_write(&bpf_devs_lock);
if (offmap->netdev)
__bpf_map_offload_destroy(offmap);
up_write(&bpf_devs_lock);
rtnl_unlock();
kfree(offmap);
}
int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value)
{
struct bpf_offloaded_map *offmap = map_to_offmap(map);
int ret = -ENODEV;
down_read(&bpf_devs_lock);
if (offmap->netdev)
ret = offmap->dev_ops->map_lookup_elem(offmap, key, value);
up_read(&bpf_devs_lock);
return ret;
}
int bpf_map_offload_update_elem(struct bpf_map *map,
void *key, void *value, u64 flags)
{
struct bpf_offloaded_map *offmap = map_to_offmap(map);
int ret = -ENODEV;
if (unlikely(flags > BPF_EXIST))
return -EINVAL;
down_read(&bpf_devs_lock);
if (offmap->netdev)
ret = offmap->dev_ops->map_update_elem(offmap, key, value,
flags);
up_read(&bpf_devs_lock);
return ret;
}
int bpf_map_offload_delete_elem(struct bpf_map *map, void *key)
{
struct bpf_offloaded_map *offmap = map_to_offmap(map);
int ret = -ENODEV;
down_read(&bpf_devs_lock);
if (offmap->netdev)
ret = offmap->dev_ops->map_delete_elem(offmap, key);
up_read(&bpf_devs_lock);
return ret;
}
int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key)
{
struct bpf_offloaded_map *offmap = map_to_offmap(map);
int ret = -ENODEV;
down_read(&bpf_devs_lock);
if (offmap->netdev)
ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key);
up_read(&bpf_devs_lock);
return ret;
}
struct ns_get_path_bpf_map_args {
struct bpf_offloaded_map *offmap;
struct bpf_map_info *info;
};
static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data)
{
struct ns_get_path_bpf_map_args *args = private_data;
struct ns_common *ns;
struct net *net;
rtnl_lock();
down_read(&bpf_devs_lock);
if (args->offmap->netdev) {
args->info->ifindex = args->offmap->netdev->ifindex;
net = dev_net(args->offmap->netdev);
get_net(net);
ns = &net->ns;
} else {
args->info->ifindex = 0;
ns = NULL;
}
up_read(&bpf_devs_lock);
rtnl_unlock();
return ns;
}
int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map)
{
struct ns_get_path_bpf_map_args args = {
.offmap = map_to_offmap(map),
.info = info,
};
struct inode *ns_inode;
struct path ns_path;
int res;
res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
if (res) {
if (!info->ifindex)
return -ENODEV;
return res;
}
ns_inode = ns_path.dentry->d_inode;
info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
info->netns_ino = ns_inode->i_ino;
path_put(&ns_path);
return 0;
}
static bool __bpf_offload_dev_match(struct bpf_prog *prog,
struct net_device *netdev)
{
struct bpf_offload_netdev *ondev1, *ondev2;
struct bpf_prog_offload *offload;
if (!bpf_prog_is_dev_bound(prog->aux))
return false;
offload = prog->aux->offload;
if (!offload)
return false;
if (offload->netdev == netdev)
return true;
ondev1 = bpf_offload_find_netdev(offload->netdev);
ondev2 = bpf_offload_find_netdev(netdev);
return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev;
}
bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev)
{
bool ret;
down_read(&bpf_devs_lock);
ret = __bpf_offload_dev_match(prog, netdev);
up_read(&bpf_devs_lock);
return ret;
}
EXPORT_SYMBOL_GPL(bpf_offload_dev_match);
bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map)
{
struct bpf_offloaded_map *offmap;
bool ret;
if (!bpf_map_is_dev_bound(map))
return bpf_map_offload_neutral(map);
offmap = map_to_offmap(map);
down_read(&bpf_devs_lock);
ret = __bpf_offload_dev_match(prog, offmap->netdev);
up_read(&bpf_devs_lock);
return ret;
}
int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
struct net_device *netdev)
{
struct bpf_offload_netdev *ondev;
int err;
ondev = kzalloc(sizeof(*ondev), GFP_KERNEL);
if (!ondev)
return -ENOMEM;
ondev->netdev = netdev;
ondev->offdev = offdev;
INIT_LIST_HEAD(&ondev->progs);
INIT_LIST_HEAD(&ondev->maps);
down_write(&bpf_devs_lock);
err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params);
if (err) {
netdev_warn(netdev, "failed to register for BPF offload\n");
goto err_unlock_free;
}
list_add(&ondev->offdev_netdevs, &offdev->netdevs);
up_write(&bpf_devs_lock);
return 0;
err_unlock_free:
up_write(&bpf_devs_lock);
kfree(ondev);
return err;
}
EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register);
void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
struct net_device *netdev)
{
struct bpf_offload_netdev *ondev, *altdev;
struct bpf_offloaded_map *offmap, *mtmp;
struct bpf_prog_offload *offload, *ptmp;
ASSERT_RTNL();
down_write(&bpf_devs_lock);
ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
if (WARN_ON(!ondev))
goto unlock;
WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params));
list_del(&ondev->offdev_netdevs);
/* Try to move the objects to another netdev of the device */
altdev = list_first_entry_or_null(&offdev->netdevs,
struct bpf_offload_netdev,
offdev_netdevs);
if (altdev) {
list_for_each_entry(offload, &ondev->progs, offloads)
offload->netdev = altdev->netdev;
list_splice_init(&ondev->progs, &altdev->progs);
list_for_each_entry(offmap, &ondev->maps, offloads)
offmap->netdev = altdev->netdev;
list_splice_init(&ondev->maps, &altdev->maps);
} else {
list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads)
__bpf_prog_offload_destroy(offload->prog);
list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads)
__bpf_map_offload_destroy(offmap);
}
WARN_ON(!list_empty(&ondev->progs));
WARN_ON(!list_empty(&ondev->maps));
kfree(ondev);
unlock:
up_write(&bpf_devs_lock);
}
EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister);
struct bpf_offload_dev *
bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops, void *priv)
{
struct bpf_offload_dev *offdev;
int err;
down_write(&bpf_devs_lock);
if (!offdevs_inited) {
err = rhashtable_init(&offdevs, &offdevs_params);
if (err) {
up_write(&bpf_devs_lock);
return ERR_PTR(err);
}
offdevs_inited = true;
}
up_write(&bpf_devs_lock);
offdev = kzalloc(sizeof(*offdev), GFP_KERNEL);
if (!offdev)
return ERR_PTR(-ENOMEM);
offdev->ops = ops;
offdev->priv = priv;
INIT_LIST_HEAD(&offdev->netdevs);
return offdev;
}
EXPORT_SYMBOL_GPL(bpf_offload_dev_create);
void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev)
{
WARN_ON(!list_empty(&offdev->netdevs));
kfree(offdev);
}
EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy);
void *bpf_offload_dev_priv(struct bpf_offload_dev *offdev)
{
return offdev->priv;
}
EXPORT_SYMBOL_GPL(bpf_offload_dev_priv);