linux/kernel/bpf/offload.c

545 lines
12 KiB
C

/*
* 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/netdevice.h>
#include <linux/printk.h>
#include <linux/proc_ns.h>
#include <linux/rtnetlink.h>
#include <linux/rwsem.h>
/* Protects bpf_prog_offload_devs, bpf_map_offload_devs and offload members
* of all progs.
* RTNL lock cannot be taken when holding this lock.
*/
static DECLARE_RWSEM(bpf_devs_lock);
static LIST_HEAD(bpf_prog_offload_devs);
static LIST_HEAD(bpf_map_offload_devs);
static int bpf_dev_offload_check(struct net_device *netdev)
{
if (!netdev)
return -EINVAL;
if (!netdev->netdev_ops->ndo_bpf)
return -EOPNOTSUPP;
return 0;
}
int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
{
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);
if (offload->netdev->reg_state != NETREG_REGISTERED) {
err = -EINVAL;
goto err_unlock;
}
prog->aux->offload = offload;
list_add_tail(&offload->offloads, &bpf_prog_offload_devs);
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;
}
static int __bpf_offload_ndo(struct bpf_prog *prog, enum bpf_netdev_command cmd,
struct netdev_bpf *data)
{
struct bpf_prog_offload *offload = prog->aux->offload;
struct net_device *netdev;
ASSERT_RTNL();
if (!offload)
return -ENODEV;
netdev = offload->netdev;
data->command = cmd;
return netdev->netdev_ops->ndo_bpf(netdev, data);
}
int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env)
{
struct netdev_bpf data = {};
int err;
data.verifier.prog = env->prog;
rtnl_lock();
err = __bpf_offload_ndo(env->prog, BPF_OFFLOAD_VERIFIER_PREP, &data);
if (err)
goto exit_unlock;
env->prog->aux->offload->dev_ops = data.verifier.ops;
env->prog->aux->offload->dev_state = true;
exit_unlock:
rtnl_unlock();
return err;
}
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->dev_ops->insn_hook(env, insn_idx, prev_insn_idx);
up_read(&bpf_devs_lock);
return ret;
}
static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
{
struct bpf_prog_offload *offload = prog->aux->offload;
struct netdev_bpf data = {};
data.offload.prog = prog;
if (offload->dev_state)
WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data));
/* 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)
{
rtnl_lock();
down_write(&bpf_devs_lock);
if (prog->aux->offload)
__bpf_prog_offload_destroy(prog);
up_write(&bpf_devs_lock);
rtnl_unlock();
}
static int bpf_prog_offload_translate(struct bpf_prog *prog)
{
struct netdev_bpf data = {};
int ret;
data.offload.prog = prog;
rtnl_lock();
ret = __bpf_offload_ndo(prog, BPF_OFFLOAD_TRANSLATE, &data);
rtnl_unlock();
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;
void *res;
u32 ulen;
res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
if (IS_ERR(res)) {
if (!info->ifindex)
return -ENODEV;
return PTR_ERR(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_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;
err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC);
if (err)
goto err_unlock;
list_add_tail(&offmap->offloads, &bpf_map_offload_devs);
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;
void *res;
res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
if (IS_ERR(res)) {
if (!info->ifindex)
return -ENODEV;
return PTR_ERR(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;
}
bool bpf_offload_dev_match(struct bpf_prog *prog, struct bpf_map *map)
{
struct bpf_offloaded_map *offmap;
struct bpf_prog_offload *offload;
bool ret;
if (!bpf_prog_is_dev_bound(prog->aux))
return false;
if (!bpf_map_is_dev_bound(map))
return bpf_map_offload_neutral(map);
down_read(&bpf_devs_lock);
offload = prog->aux->offload;
offmap = map_to_offmap(map);
ret = offload && offload->netdev == offmap->netdev;
up_read(&bpf_devs_lock);
return ret;
}
static void bpf_offload_orphan_all_progs(struct net_device *netdev)
{
struct bpf_prog_offload *offload, *tmp;
list_for_each_entry_safe(offload, tmp, &bpf_prog_offload_devs, offloads)
if (offload->netdev == netdev)
__bpf_prog_offload_destroy(offload->prog);
}
static void bpf_offload_orphan_all_maps(struct net_device *netdev)
{
struct bpf_offloaded_map *offmap, *tmp;
list_for_each_entry_safe(offmap, tmp, &bpf_map_offload_devs, offloads)
if (offmap->netdev == netdev)
__bpf_map_offload_destroy(offmap);
}
static int bpf_offload_notification(struct notifier_block *notifier,
ulong event, void *ptr)
{
struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
ASSERT_RTNL();
switch (event) {
case NETDEV_UNREGISTER:
/* ignore namespace changes */
if (netdev->reg_state != NETREG_UNREGISTERING)
break;
down_write(&bpf_devs_lock);
bpf_offload_orphan_all_progs(netdev);
bpf_offload_orphan_all_maps(netdev);
up_write(&bpf_devs_lock);
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block bpf_offload_notifier = {
.notifier_call = bpf_offload_notification,
};
static int __init bpf_offload_init(void)
{
register_netdevice_notifier(&bpf_offload_notifier);
return 0;
}
subsys_initcall(bpf_offload_init);