1 /* 2 * Tap functions for AF_VSOCK sockets. 3 * 4 * Code based on net/netlink/af_netlink.c tap functions. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 12 #include <linux/module.h> 13 #include <net/sock.h> 14 #include <net/af_vsock.h> 15 #include <linux/if_arp.h> 16 17 static DEFINE_SPINLOCK(vsock_tap_lock); 18 static struct list_head vsock_tap_all __read_mostly = 19 LIST_HEAD_INIT(vsock_tap_all); 20 21 int vsock_add_tap(struct vsock_tap *vt) 22 { 23 if (unlikely(vt->dev->type != ARPHRD_VSOCKMON)) 24 return -EINVAL; 25 26 __module_get(vt->module); 27 28 spin_lock(&vsock_tap_lock); 29 list_add_rcu(&vt->list, &vsock_tap_all); 30 spin_unlock(&vsock_tap_lock); 31 32 return 0; 33 } 34 EXPORT_SYMBOL_GPL(vsock_add_tap); 35 36 int vsock_remove_tap(struct vsock_tap *vt) 37 { 38 struct vsock_tap *tmp; 39 bool found = false; 40 41 spin_lock(&vsock_tap_lock); 42 43 list_for_each_entry(tmp, &vsock_tap_all, list) { 44 if (vt == tmp) { 45 list_del_rcu(&vt->list); 46 found = true; 47 goto out; 48 } 49 } 50 51 pr_warn("vsock_remove_tap: %p not found\n", vt); 52 out: 53 spin_unlock(&vsock_tap_lock); 54 55 synchronize_net(); 56 57 if (found) 58 module_put(vt->module); 59 60 return found ? 0 : -ENODEV; 61 } 62 EXPORT_SYMBOL_GPL(vsock_remove_tap); 63 64 static int __vsock_deliver_tap_skb(struct sk_buff *skb, 65 struct net_device *dev) 66 { 67 int ret = 0; 68 struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC); 69 70 if (nskb) { 71 dev_hold(dev); 72 73 nskb->dev = dev; 74 ret = dev_queue_xmit(nskb); 75 if (unlikely(ret > 0)) 76 ret = net_xmit_errno(ret); 77 78 dev_put(dev); 79 } 80 81 return ret; 82 } 83 84 static void __vsock_deliver_tap(struct sk_buff *skb) 85 { 86 int ret; 87 struct vsock_tap *tmp; 88 89 list_for_each_entry_rcu(tmp, &vsock_tap_all, list) { 90 ret = __vsock_deliver_tap_skb(skb, tmp->dev); 91 if (unlikely(ret)) 92 break; 93 } 94 } 95 96 void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque) 97 { 98 struct sk_buff *skb; 99 100 rcu_read_lock(); 101 102 if (likely(list_empty(&vsock_tap_all))) 103 goto out; 104 105 skb = build_skb(opaque); 106 if (skb) { 107 __vsock_deliver_tap(skb); 108 consume_skb(skb); 109 } 110 111 out: 112 rcu_read_unlock(); 113 } 114 EXPORT_SYMBOL_GPL(vsock_deliver_tap); 115