LXR linux/net/vmw_vsock/af_vsock

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Tap functions for AF_VSOCK sockets.
   4 *
   5 * Code based on net/netlink/af_netlink.c tap functions.
   6 */
   7
   8#include <linux/module.h>
   9#include <net/sock.h>
  10#include <net/af_vsock.h>
  11#include <linux/if_arp.h>
  12
  13static DEFINE_SPINLOCK(vsock_tap_lock);
  14static struct list_head vsock_tap_all __read_mostly =
  15                                LIST_HEAD_INIT(vsock_tap_all);
  16
  17int vsock_add_tap(struct vsock_tap *vt)
  18{
  19        if (unlikely(vt->dev->type != ARPHRD_VSOCKMON))
  20                return -EINVAL;
  21
  22        __module_get(vt->module);
  23
  24        spin_lock(&vsock_tap_lock);
  25        list_add_rcu(&vt->list, &vsock_tap_all);
  26        spin_unlock(&vsock_tap_lock);
  27
  28        return 0;
  29}
  30EXPORT_SYMBOL_GPL(vsock_add_tap);
  31
  32int vsock_remove_tap(struct vsock_tap *vt)
  33{
  34        struct vsock_tap *tmp;
  35        bool found = false;
  36
  37        spin_lock(&vsock_tap_lock);
  38
  39        list_for_each_entry(tmp, &vsock_tap_all, list) {
  40                if (vt == tmp) {
  41                        list_del_rcu(&vt->list);
  42                        found = true;
  43                        goto out;
  44                }
  45        }
  46
  47        pr_warn("vsock_remove_tap: %p not found\n", vt);
  48out:
  49        spin_unlock(&vsock_tap_lock);
  50
  51        synchronize_net();
  52
  53        if (found)
  54                module_put(vt->module);
  55
  56        return found ? 0 : -ENODEV;
  57}
  58EXPORT_SYMBOL_GPL(vsock_remove_tap);
  59
  60static int __vsock_deliver_tap_skb(struct sk_buff *skb,
  61                                   struct net_device *dev)
  62{
  63        int ret = 0;
  64        struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
  65
  66        if (nskb) {
  67                dev_hold(dev);
  68
  69                nskb->dev = dev;
  70                ret = dev_queue_xmit(nskb);
  71                if (unlikely(ret > 0))
  72                        ret = net_xmit_errno(ret);
  73
  74                dev_put(dev);
  75        }
  76
  77        return ret;
  78}
  79
  80static void __vsock_deliver_tap(struct sk_buff *skb)
  81{
  82        int ret;
  83        struct vsock_tap *tmp;
  84
  85        list_for_each_entry_rcu(tmp, &vsock_tap_all, list) {
  86                ret = __vsock_deliver_tap_skb(skb, tmp->dev);
  87                if (unlikely(ret))
  88                        break;
  89        }
  90}
  91
  92void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque)
  93{
  94        struct sk_buff *skb;
  95
  96        rcu_read_lock();
  97
  98        if (likely(list_empty(&vsock_tap_all)))
  99                goto out;
 100
 101        skb = build_skb(opaque);
 102        if (skb) {
 103                __vsock_deliver_tap(skb);
 104                consume_skb(skb);
 105        }
 106
 107out:
 108        rcu_read_unlock();
 109}
 110EXPORT_SYMBOL_GPL(vsock_deliver_tap);
 111