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