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#include <linux/bpf.h>
#include <linux/bpf_verifier.h>
#include <linux/bug.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/printk.h>
#include <linux/rtnetlink.h>
/* protected by RTNL */
static LIST_HEAD(bpf_prog_offload_devs);
int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
{
struct net *net = current->nsproxy->net_ns;
struct bpf_dev_offload *offload;
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;
init_waitqueue_head(&offload->verifier_done);
rtnl_lock();
offload->netdev = __dev_get_by_index(net, attr->prog_ifindex);
if (!offload->netdev) {
rtnl_unlock();
kfree(offload);
return -EINVAL;
}
prog->aux->offload = offload;
list_add_tail(&offload->offloads, &bpf_prog_offload_devs);
rtnl_unlock();
return 0;
}
static int __bpf_offload_ndo(struct bpf_prog *prog, enum bpf_netdev_command cmd,
struct netdev_bpf *data)
{
struct net_device *netdev = prog->aux->offload->netdev;
ASSERT_RTNL();
if (!netdev)
return -ENODEV;
if (!netdev->netdev_ops->ndo_bpf)
return -EOPNOTSUPP;
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->dev_ops = data.verifier.ops;
env->prog->aux->offload->dev_state = true;
env->prog->aux->offload->verifier_running = true;
exit_unlock:
rtnl_unlock();
return err;
}
static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
{
struct bpf_dev_offload *offload = prog->aux->offload;
struct netdev_bpf data = {};
/* Caution - if netdev is destroyed before the program, this function
* will be called twice.
*/
data.offload.prog = prog;
if (offload->verifier_running)
wait_event(offload->verifier_done, !offload->verifier_running);
if (offload->dev_state)
WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data));
offload->dev_state = false;
list_del_init(&offload->offloads);
offload->netdev = NULL;
}
void bpf_prog_offload_destroy(struct bpf_prog *prog)
{
struct bpf_dev_offload *offload = prog->aux->offload;
offload->verifier_running = false;
wake_up(&offload->verifier_done);
rtnl_lock();
__bpf_prog_offload_destroy(prog);
rtnl_unlock();
kfree(offload);
}
static int bpf_prog_offload_translate(struct bpf_prog *prog)
{
struct bpf_dev_offload *offload = prog->aux->offload;
struct netdev_bpf data = {};
int ret;
data.offload.prog = prog;
offload->verifier_running = false;
wake_up(&offload->verifier_done);
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);
}
u32 bpf_prog_offload_ifindex(struct bpf_prog *prog)
{
struct bpf_dev_offload *offload = prog->aux->offload;
u32 ifindex;
rtnl_lock();
ifindex = offload->netdev ? offload->netdev->ifindex : 0;
rtnl_unlock();
return ifindex;
}
const struct bpf_prog_ops bpf_offload_prog_ops = {
};
static int bpf_offload_notification(struct notifier_block *notifier,
ulong event, void *ptr)
{
struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
struct bpf_dev_offload *offload, *tmp;
ASSERT_RTNL();
switch (event) {
case NETDEV_UNREGISTER:
/* ignore namespace changes */
if (netdev->reg_state != NETREG_UNREGISTERING)
break;
list_for_each_entry_safe(offload, tmp, &bpf_prog_offload_devs,
offloads) {
if (offload->netdev == netdev)
__bpf_prog_offload_destroy(offload->prog);
}
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);
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