1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2019 Vincenzo Maffione <vmaffione@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
19 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
20 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
21 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
22 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
24 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
25 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef __NET_BACKENDS_PRIV_H__
29#define __NET_BACKENDS_PRIV_H__
30
31#include <sys/linker_set.h>
32
33/*
34 * Each network backend registers a set of function pointers that are
35 * used to implement the net backends API.  Frontends should not invoke
36 * these functions directly, but should instead use the interface provided by
37 * net_backends.h.
38 */
39struct net_backend {
40	const char *prefix;	/* prefix matching this backend */
41
42	/*
43	 * Routines used to initialize and cleanup the resources needed
44	 * by a backend. The cleanup function is used internally,
45	 * and should not be called by the frontend.
46	 */
47	int (*init)(struct net_backend *be, const char *devname,
48	    nvlist_t *nvl, net_be_rxeof_t cb, void *param);
49	void (*cleanup)(struct net_backend *be);
50
51	/*
52	 * Called to serve a guest transmit request. The scatter-gather
53	 * vector provided by the caller has 'iovcnt' elements and contains
54	 * the packet to send.
55	 */
56	ssize_t (*send)(struct net_backend *be, const struct iovec *iov,
57	    int iovcnt);
58
59	/*
60	 * Get the length of the next packet that can be received from
61	 * the backend. If no packets are currently available, this
62	 * function returns 0.
63	 */
64	ssize_t (*peek_recvlen)(struct net_backend *be);
65
66	/*
67	 * Called to receive a packet from the backend. When the function
68	 * returns a positive value 'len', the scatter-gather vector
69	 * provided by the caller contains a packet with such length.
70	 * The function returns 0 if the backend doesn't have a new packet to
71	 * receive.
72	 */
73	ssize_t (*recv)(struct net_backend *be, const struct iovec *iov,
74	    int iovcnt);
75
76	/*
77	 * Ask the backend to enable or disable receive operation in the
78	 * backend. On return from a disable operation, it is guaranteed
79	 * that the receive callback won't be called until receive is
80	 * enabled again. Note however that it is up to the caller to make
81	 * sure that netbe_recv() is not currently being executed by another
82	 * thread.
83	 */
84	void (*recv_enable)(struct net_backend *be);
85	void (*recv_disable)(struct net_backend *be);
86
87	/*
88	 * Ask the backend for the virtio-net features it is able to
89	 * support. Possible features are TSO, UFO and checksum offloading
90	 * in both rx and tx direction and for both IPv4 and IPv6.
91	 */
92	uint64_t (*get_cap)(struct net_backend *be);
93
94	/*
95	 * Tell the backend to enable/disable the specified virtio-net
96	 * features (capabilities).
97	 */
98	int (*set_cap)(struct net_backend *be, uint64_t features,
99	    unsigned int vnet_hdr_len);
100
101	struct pci_vtnet_softc *sc;
102	int fd;
103
104	/*
105	 * Length of the virtio-net header used by the backend and the
106	 * frontend, respectively. A zero value means that the header
107	 * is not used.
108	 */
109	unsigned int be_vnet_hdr_len;
110	unsigned int fe_vnet_hdr_len;
111
112	/* Size of backend-specific private data. */
113	size_t priv_size;
114
115	/* Backend-specific private data follows. */
116};
117
118#define	NET_BE_PRIV(be)		((void *)((be) + 1))
119
120SET_DECLARE(net_backend_set, struct net_backend);
121
122#define VNET_HDR_LEN	sizeof(struct virtio_net_rxhdr)
123
124/*
125 * Export the tap backend routines for the benefit of other backends which have
126 * a similar interface to the kernel, i.e., they send and receive data using
127 * standard I/O system calls with a single file descriptor.
128 */
129
130struct tap_priv {
131	struct mevent *mevp;
132	/*
133	 * A bounce buffer that allows us to implement the peek_recvlen
134	 * callback. In the future we may get the same information from
135	 * the kevent data.
136	 */
137	char bbuf[1 << 16];
138	ssize_t bbuflen;
139};
140
141void	tap_cleanup(struct net_backend *be);
142ssize_t	tap_send(struct net_backend *be, const struct iovec *iov, int iovcnt);
143ssize_t	tap_recv(struct net_backend *be, const struct iovec *iov, int iovcnt);
144ssize_t	tap_peek_recvlen(struct net_backend *be);
145void	tap_recv_enable(struct net_backend *be);
146ssize_t	tap_recv(struct net_backend *be, const struct iovec *iov, int iovcnt);
147void	tap_recv_disable(struct net_backend *be);
148uint64_t tap_get_cap(struct net_backend *be);
149int	tap_set_cap(struct net_backend *be, uint64_t features,
150	    unsigned vnet_hdr_len);
151
152#endif /* !__NET_BACKENDS_PRIV_H__ */
153