1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Tap functions for AF_VSOCK sockets.
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Code based on net/netlink/af_netlink.c tap functions.
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/module.h>
9*4882a593Smuzhiyun #include <net/sock.h>
10*4882a593Smuzhiyun #include <net/af_vsock.h>
11*4882a593Smuzhiyun #include <linux/if_arp.h>
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun static DEFINE_SPINLOCK(vsock_tap_lock);
14*4882a593Smuzhiyun static struct list_head vsock_tap_all __read_mostly =
15*4882a593Smuzhiyun LIST_HEAD_INIT(vsock_tap_all);
16*4882a593Smuzhiyun
vsock_add_tap(struct vsock_tap * vt)17*4882a593Smuzhiyun int vsock_add_tap(struct vsock_tap *vt)
18*4882a593Smuzhiyun {
19*4882a593Smuzhiyun if (unlikely(vt->dev->type != ARPHRD_VSOCKMON))
20*4882a593Smuzhiyun return -EINVAL;
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun __module_get(vt->module);
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun spin_lock(&vsock_tap_lock);
25*4882a593Smuzhiyun list_add_rcu(&vt->list, &vsock_tap_all);
26*4882a593Smuzhiyun spin_unlock(&vsock_tap_lock);
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun return 0;
29*4882a593Smuzhiyun }
30*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(vsock_add_tap);
31*4882a593Smuzhiyun
vsock_remove_tap(struct vsock_tap * vt)32*4882a593Smuzhiyun int vsock_remove_tap(struct vsock_tap *vt)
33*4882a593Smuzhiyun {
34*4882a593Smuzhiyun struct vsock_tap *tmp;
35*4882a593Smuzhiyun bool found = false;
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun spin_lock(&vsock_tap_lock);
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun list_for_each_entry(tmp, &vsock_tap_all, list) {
40*4882a593Smuzhiyun if (vt == tmp) {
41*4882a593Smuzhiyun list_del_rcu(&vt->list);
42*4882a593Smuzhiyun found = true;
43*4882a593Smuzhiyun goto out;
44*4882a593Smuzhiyun }
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun pr_warn("vsock_remove_tap: %p not found\n", vt);
48*4882a593Smuzhiyun out:
49*4882a593Smuzhiyun spin_unlock(&vsock_tap_lock);
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun synchronize_net();
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun if (found)
54*4882a593Smuzhiyun module_put(vt->module);
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun return found ? 0 : -ENODEV;
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(vsock_remove_tap);
59*4882a593Smuzhiyun
__vsock_deliver_tap_skb(struct sk_buff * skb,struct net_device * dev)60*4882a593Smuzhiyun static int __vsock_deliver_tap_skb(struct sk_buff *skb,
61*4882a593Smuzhiyun struct net_device *dev)
62*4882a593Smuzhiyun {
63*4882a593Smuzhiyun int ret = 0;
64*4882a593Smuzhiyun struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun if (nskb) {
67*4882a593Smuzhiyun dev_hold(dev);
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun nskb->dev = dev;
70*4882a593Smuzhiyun ret = dev_queue_xmit(nskb);
71*4882a593Smuzhiyun if (unlikely(ret > 0))
72*4882a593Smuzhiyun ret = net_xmit_errno(ret);
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun dev_put(dev);
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun return ret;
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
__vsock_deliver_tap(struct sk_buff * skb)80*4882a593Smuzhiyun static void __vsock_deliver_tap(struct sk_buff *skb)
81*4882a593Smuzhiyun {
82*4882a593Smuzhiyun int ret;
83*4882a593Smuzhiyun struct vsock_tap *tmp;
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun list_for_each_entry_rcu(tmp, &vsock_tap_all, list) {
86*4882a593Smuzhiyun ret = __vsock_deliver_tap_skb(skb, tmp->dev);
87*4882a593Smuzhiyun if (unlikely(ret))
88*4882a593Smuzhiyun break;
89*4882a593Smuzhiyun }
90*4882a593Smuzhiyun }
91*4882a593Smuzhiyun
vsock_deliver_tap(struct sk_buff * build_skb (void * opaque),void * opaque)92*4882a593Smuzhiyun void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque)
93*4882a593Smuzhiyun {
94*4882a593Smuzhiyun struct sk_buff *skb;
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun rcu_read_lock();
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun if (likely(list_empty(&vsock_tap_all)))
99*4882a593Smuzhiyun goto out;
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun skb = build_skb(opaque);
102*4882a593Smuzhiyun if (skb) {
103*4882a593Smuzhiyun __vsock_deliver_tap(skb);
104*4882a593Smuzhiyun consume_skb(skb);
105*4882a593Smuzhiyun }
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun out:
108*4882a593Smuzhiyun rcu_read_unlock();
109*4882a593Smuzhiyun }
110*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(vsock_deliver_tap);
111