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net/vmw_vsock/af_vsock_tap.c 2.19 KB
531b37483   Gerard Garcia   VSOCK: Add vsockm...
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  /*
   * Tap functions for AF_VSOCK sockets.
   *
   * Code based on net/netlink/af_netlink.c tap functions.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  
  #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
  ", 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);