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linux/net/vmw_vsock/af_vsock_tap.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Tap functions for AF_VSOCK sockets.
*
* Code based on net/netlink/af_netlink.c tap functions.
*/
#include <linux/module.h>
#include <net/sock.h>
#include <net/af_vsock.h>
#include <linux/if_arp.h>
static DEFINE_SPINLOCK(vsock_tap_lock);
static struct list_head vsock_tap_all __read_mostly =
LIST_HEAD_INIT(vsock_tap_all);
int vsock_add_tap(struct vsock_tap *vt)
{
if (unlikely(vt->dev->type != ARPHRD_VSOCKMON))
return -EINVAL;
__module_get(vt->module);
spin_lock(&vsock_tap_lock);
list_add_rcu(&vt->list, &vsock_tap_all);
spin_unlock(&vsock_tap_lock);
return 0;
}
EXPORT_SYMBOL_GPL(vsock_add_tap);
int vsock_remove_tap(struct vsock_tap *vt)
{
struct vsock_tap *tmp;
bool found = false;
spin_lock(&vsock_tap_lock);
list_for_each_entry(tmp, &vsock_tap_all, list) {
if (vt == tmp) {
list_del_rcu(&vt->list);
found = true;
goto out;
}
}
pr_warn("vsock_remove_tap: %p not found\n", vt);
out:
spin_unlock(&vsock_tap_lock);
synchronize_net();
if (found)
module_put(vt->module);
return found ? 0 : -ENODEV;
}
EXPORT_SYMBOL_GPL(vsock_remove_tap);
static int __vsock_deliver_tap_skb(struct sk_buff *skb,
struct net_device *dev)
{
int ret = 0;
struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
if (nskb) {
dev_hold(dev);
nskb->dev = dev;
ret = dev_queue_xmit(nskb);
if (unlikely(ret > 0))
ret = net_xmit_errno(ret);
dev_put(dev);
}
return ret;
}
static void __vsock_deliver_tap(struct sk_buff *skb)
{
int ret;
struct vsock_tap *tmp;
list_for_each_entry_rcu(tmp, &vsock_tap_all, list) {
ret = __vsock_deliver_tap_skb(skb, tmp->dev);
if (unlikely(ret))
break;
}
}
void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque)
{
struct sk_buff *skb;
rcu_read_lock();
if (likely(list_empty(&vsock_tap_all)))
goto out;
skb = build_skb(opaque);
if (skb) {
__vsock_deliver_tap(skb);
consume_skb(skb);
}
out:
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(vsock_deliver_tap);