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 | |
13 | static DEFINE_SPINLOCK(vsock_tap_lock); |
14 | static struct list_head vsock_tap_all __read_mostly = |
15 | LIST_HEAD_INIT(vsock_tap_all); |
16 | |
17 | int vsock_add_tap(struct vsock_tap *vt) |
18 | { |
19 | if (unlikely(vt->dev->type != ARPHRD_VSOCKMON)) |
20 | return -EINVAL; |
21 | |
22 | __module_get(module: vt->module); |
23 | |
24 | spin_lock(lock: &vsock_tap_lock); |
25 | list_add_rcu(new: &vt->list, head: &vsock_tap_all); |
26 | spin_unlock(lock: &vsock_tap_lock); |
27 | |
28 | return 0; |
29 | } |
30 | EXPORT_SYMBOL_GPL(vsock_add_tap); |
31 | |
32 | int vsock_remove_tap(struct vsock_tap *vt) |
33 | { |
34 | struct vsock_tap *tmp; |
35 | bool found = false; |
36 | |
37 | spin_lock(lock: &vsock_tap_lock); |
38 | |
39 | list_for_each_entry(tmp, &vsock_tap_all, list) { |
40 | if (vt == tmp) { |
41 | list_del_rcu(entry: &vt->list); |
42 | found = true; |
43 | goto out; |
44 | } |
45 | } |
46 | |
47 | pr_warn("vsock_remove_tap: %p not found\n" , vt); |
48 | out: |
49 | spin_unlock(lock: &vsock_tap_lock); |
50 | |
51 | synchronize_net(); |
52 | |
53 | if (found) |
54 | module_put(module: vt->module); |
55 | |
56 | return found ? 0 : -ENODEV; |
57 | } |
58 | EXPORT_SYMBOL_GPL(vsock_remove_tap); |
59 | |
60 | static 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(skb: nskb); |
71 | if (unlikely(ret > 0)) |
72 | ret = net_xmit_errno(ret); |
73 | |
74 | dev_put(dev); |
75 | } |
76 | |
77 | return ret; |
78 | } |
79 | |
80 | static 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, dev: tmp->dev); |
87 | if (unlikely(ret)) |
88 | break; |
89 | } |
90 | } |
91 | |
92 | void 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 | |
107 | out: |
108 | rcu_read_unlock(); |
109 | } |
110 | EXPORT_SYMBOL_GPL(vsock_deliver_tap); |
111 | |