// SPDX-License-Identifier: GPL-2.0-only/* loopback transport for vsock using virtio_transport_common APIs * * Copyright (C) 2013-2019 Red Hat, Inc. * Authors: Asias He <asias@redhat.com> *          Stefan Hajnoczi <stefanha@redhat.com> *          Stefano Garzarella <sgarzare@redhat.com> * */#include <linux/spinlock.h>#include <linux/module.h>#include <linux/list.h>#include <linux/virtio_vsock.h> struct vsock_loopback {	struct workqueue_struct *workqueue; 	struct sk_buff_head pkt_queue;	struct work_struct pkt_work;}; static struct vsock_loopback the_vsock_loopback; static u32 vsock_loopback_get_local_cid(void){	return VMADDR_CID_LOCAL;} static int vsock_loopback_send_pkt(struct sk_buff *skb, struct net *net){	struct vsock_loopback *vsock = &the_vsock_loopback;	int len = skb->len; 	virtio_vsock_skb_queue_tail(&vsock->pkt_queue, skb);	queue_work(vsock->workqueue, &vsock->pkt_work); 	return len;} static int vsock_loopback_cancel_pkt(struct vsock_sock *vsk){	struct vsock_loopback *vsock = &the_vsock_loopback; 	virtio_transport_purge_skbs(vsk, &vsock->pkt_queue); 	return 0;} static bool vsock_loopback_seqpacket_allow(struct vsock_sock *vsk,					   u32 remote_cid); static bool vsock_loopback_stream_allow(struct vsock_sock *vsk, u32 cid,					u32 port){	return true;} static bool vsock_loopback_msgzerocopy_allow(void){	return true;} static struct virtio_transport loopback_transport = {	.transport = {		.module                   = THIS_MODULE, 		.get_local_cid            = vsock_loopback_get_local_cid, 		.init                     = virtio_transport_do_socket_init,		.destruct                 = virtio_transport_destruct,		.release                  = virtio_transport_release,		.connect                  = virtio_transport_connect,		.shutdown                 = virtio_transport_shutdown,		.cancel_pkt               = vsock_loopback_cancel_pkt, 		.dgram_bind               = virtio_transport_dgram_bind,		.dgram_dequeue            = virtio_transport_dgram_dequeue,		.dgram_enqueue            = virtio_transport_dgram_enqueue,		.dgram_allow              = virtio_transport_dgram_allow, 		.stream_dequeue           = virtio_transport_stream_dequeue,		.stream_enqueue           = virtio_transport_stream_enqueue,		.stream_has_data          = virtio_transport_stream_has_data,		.stream_has_space         = virtio_transport_stream_has_space,		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,		.stream_is_active         = virtio_transport_stream_is_active,		.stream_allow             = vsock_loopback_stream_allow, 		.seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,		.seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,		.seqpacket_allow          = vsock_loopback_seqpacket_allow,		.seqpacket_has_data       = virtio_transport_seqpacket_has_data, 		.msgzerocopy_allow        = vsock_loopback_msgzerocopy_allow, 		.notify_poll_in           = virtio_transport_notify_poll_in,		.notify_poll_out          = virtio_transport_notify_poll_out,		.notify_recv_init         = virtio_transport_notify_recv_init,		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,		.notify_send_init         = virtio_transport_notify_send_init,		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,		.notify_buffer_size       = virtio_transport_notify_buffer_size,		.notify_set_rcvlowat      = virtio_transport_notify_set_rcvlowat, 		.unsent_bytes             = virtio_transport_unsent_bytes, 		.read_skb = virtio_transport_read_skb,	}, 	.send_pkt = vsock_loopback_send_pkt,}; static boolvsock_loopback_seqpacket_allow(struct vsock_sock *vsk, u32 remote_cid){	return vsock_net_mode_global(vsk);} static void vsock_loopback_work(struct work_struct *work){	struct vsock_loopback *vsock =		container_of(work, struct vsock_loopback, pkt_work);	struct sk_buff_head pkts;	struct sk_buff *skb; 	skb_queue_head_init(&pkts); 	spin_lock_bh(&vsock->pkt_queue.lock);	skb_queue_splice_init(&vsock->pkt_queue, &pkts);	spin_unlock_bh(&vsock->pkt_queue.lock); 	while ((skb = __skb_dequeue(&pkts))) {		/* Decrement the bytes_unsent counter without deallocating skb		 * It is freed by the receiver.		 */		virtio_transport_consume_skb_sent(skb, false);		virtio_transport_deliver_tap_pkt(skb);		virtio_transport_recv_pkt(&loopback_transport, skb,					  sock_net(skb->sk));	}} static int __init vsock_loopback_init(void){	struct vsock_loopback *vsock = &the_vsock_loopback;	int ret; 	vsock->workqueue = alloc_workqueue("vsock-loopback", WQ_PERCPU, 0);	if (!vsock->workqueue)		return -ENOMEM; 	skb_queue_head_init(&vsock->pkt_queue);	INIT_WORK(&vsock->pkt_work, vsock_loopback_work); 	ret = vsock_core_register(&loopback_transport.transport,				  VSOCK_TRANSPORT_F_LOCAL);	if (ret)		goto out_wq; 	return 0; out_wq:	destroy_workqueue(vsock->workqueue);	return ret;} static void __exit vsock_loopback_exit(void){	struct vsock_loopback *vsock = &the_vsock_loopback; 	vsock_core_unregister(&loopback_transport.transport); 	flush_work(&vsock->pkt_work); 	virtio_vsock_skb_queue_purge(&vsock->pkt_queue); 	destroy_workqueue(vsock->workqueue);} module_init(vsock_loopback_init);module_exit(vsock_loopback_exit);MODULE_LICENSE("GPL v2");MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");MODULE_DESCRIPTION("loopback transport for vsock");MODULE_ALIAS_NETPROTO(PF_VSOCK);