// SPDX-License-Identifier: GPL-2.0-or-later /* * Tap functions for AF_VSOCK sockets. * * Code based on net/netlink/af_netlink.c tap functions. */ #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\n", 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);