1/*-
2 * Copyright (c) 1982, 1986, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following edsclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following edsclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE EDSCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	From: @(#)if_loop.c	8.1 (Berkeley) 6/10/93
30 * $FreeBSD$
31 */
32
33/*
34 * Discard interface driver for protocol testing and timing.
35 * Mimics an Ethernet device so that VLANs can be attached to it etc.
36 */
37
38#include <sys/param.h>		/* types, important constants */
39#include <sys/kernel.h>		/* SYSINIT for load-time initializations */
40#include <sys/malloc.h>		/* malloc(9) */
41#include <sys/module.h>		/* module(9) */
42#include <sys/mbuf.h>		/* mbuf(9) */
43#include <sys/socket.h>		/* struct ifreq */
44#include <sys/sockio.h>		/* socket ioctl's */
45/* #include <sys/systm.h> if you need printf(9) or other all-purpose globals */
46
47#include <net/bpf.h>		/* bpf(9) */
48#include <net/ethernet.h>	/* Ethernet related constants and types */
49#include <net/if.h>		/* basic part of ifnet(9) */
50#include <net/if_clone.h>	/* network interface cloning */
51#include <net/if_types.h>	/* IFT_ETHER and friends */
52#include <net/if_var.h>		/* kernel-only part of ifnet(9) */
53
54static const char edscname[] = "edsc";
55
56/*
57 * Software configuration of an interface specific to this device type.
58 */
59struct edsc_softc {
60	struct ifnet	*sc_ifp; /* ptr to generic interface configuration */
61
62	/*
63	 * A non-null driver can keep various things here, for instance,
64	 * the hardware revision, cached values of write-only registers, etc.
65	 */
66};
67
68/*
69 * Attach to the interface cloning framework.
70 */
71static struct if_clone *edsc_cloner;
72static int	edsc_clone_create(struct if_clone *, int, caddr_t);
73static void	edsc_clone_destroy(struct ifnet *);
74
75/*
76 * Interface driver methods.
77 */
78static void	edsc_init(void *dummy);
79/* static void edsc_input(struct ifnet *ifp, struct mbuf *m); would be here */
80static int	edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
81static void	edsc_start(struct ifnet *ifp);
82
83/*
84 * We'll allocate softc instances from this.
85 */
86static		MALLOC_DEFINE(M_EDSC, edscname, "Ethernet discard interface");
87
88/*
89 * Create an interface instance.
90 */
91static int
92edsc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
93{
94	struct edsc_softc	*sc;
95	struct ifnet		*ifp;
96	static u_char		 eaddr[ETHER_ADDR_LEN];	/* 0:0:0:0:0:0 */
97
98	/*
99	 * Allocate soft and ifnet structures.  Link each to the other.
100	 */
101	sc = malloc(sizeof(struct edsc_softc), M_EDSC, M_WAITOK | M_ZERO);
102	ifp = sc->sc_ifp = if_alloc(IFT_ETHER);
103	if (ifp == NULL) {
104		free(sc, M_EDSC);
105		return (ENOSPC);
106	}
107
108	ifp->if_softc = sc;
109
110	/*
111	 * Get a name for this particular interface in its ifnet structure.
112	 */
113	if_initname(ifp, edscname, unit);
114
115	/*
116	 * Typical Ethernet interface flags: we can do broadcast and
117	 * multicast but can't hear our own broadcasts or multicasts.
118	 */
119	ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST | IFF_SIMPLEX;
120
121	/*
122	 * We can pretent we have the whole set of hardware features
123	 * because we just discard all packets we get from the upper layer.
124	 * However, the features are disabled initially.  They can be
125	 * enabled via edsc_ioctl() when needed.
126	 */
127	ifp->if_capabilities =
128	    IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_HWCSUM |
129	    IFCAP_HWCSUM | IFCAP_TSO |
130	    IFCAP_JUMBO_MTU;
131	ifp->if_capenable = 0;
132
133	/*
134	 * Set the interface driver methods.
135	 */
136	ifp->if_init = edsc_init;
137	/* ifp->if_input = edsc_input; */
138	ifp->if_ioctl = edsc_ioctl;
139	ifp->if_start = edsc_start;
140
141	/*
142	 * Set the maximum output queue length from the global parameter.
143	 */
144	ifp->if_snd.ifq_maxlen = ifqmaxlen;
145
146	/*
147	 * Do ifnet initializations common to all Ethernet drivers
148	 * and attach to the network interface framework.
149	 * TODO: Pick a non-zero link level address.
150	 */
151	ether_ifattach(ifp, eaddr);
152
153	/*
154	 * Now we can mark the interface as running, i.e., ready
155	 * for operation.
156	 */
157	ifp->if_drv_flags |= IFF_DRV_RUNNING;
158
159	return (0);
160}
161
162/*
163 * Destroy an interface instance.
164 */
165static void
166edsc_clone_destroy(struct ifnet *ifp)
167{
168	struct edsc_softc	*sc = ifp->if_softc;
169
170	/*
171	 * Detach from the network interface framework.
172	 */
173	ether_ifdetach(ifp);
174
175	/*
176	 * Free memory occupied by ifnet and softc.
177	 */
178	if_free(ifp);
179	free(sc, M_EDSC);
180}
181
182/*
183 * This method is invoked from ether_ioctl() when it's time
184 * to bring up the hardware.
185 */
186static void
187edsc_init(void *dummy)
188{
189#if 0	/* what a hardware driver would do here... */
190	struct edsc_soft	*sc = (struct edsc_softc *)dummy;
191	struct ifnet		*ifp = sc->sc_ifp;
192
193	/* blah-blah-blah */
194#endif
195}
196
197/*
198 * Network interfaces are controlled via the ioctl(2) syscall.
199 */
200static int
201edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
202{
203	struct ifreq		*ifr = (struct ifreq *)data;
204
205	switch (cmd) {
206	case SIOCSIFCAP:
207#if 1
208		/*
209		 * Just turn on any capabilities requested.
210		 * The generic ifioctl() function has already made sure
211		 * that they are supported, i.e., set in if_capabilities.
212		 */
213		ifp->if_capenable = ifr->ifr_reqcap;
214#else
215		/*
216		 * A h/w driver would need to analyze the requested
217		 * bits and program the hardware, e.g.:
218		 */
219		mask = ifp->if_capenable ^ ifr->ifr_reqcap;
220
221		if (mask & IFCAP_VLAN_HWTAGGING) {
222			ifp->if_capenable ^= IFCAP_VLAN_HWTAGGING;
223
224			if (ifp->if_capenable & IFCAP_VLAN_HWTAGGING)
225				/* blah-blah-blah */
226			else
227				/* etc-etc-etc */
228		}
229#endif
230		break;
231
232	default:
233		/*
234		 * Offload the rest onto the common Ethernet handler.
235		 */
236		return (ether_ioctl(ifp, cmd, data));
237	}
238
239	return (0);
240}
241
242/*
243 * Process the output queue.
244 */
245static void
246edsc_start(struct ifnet *ifp)
247{
248	struct mbuf		*m;
249
250	/*
251	 * A hardware interface driver can set IFF_DRV_OACTIVE
252	 * in ifp->if_drv_flags:
253	 *
254	 * ifp->if_drv_flags |= IFF_DRV_OACTIVE;
255	 *
256	 * to prevent if_start from being invoked again while the
257	 * transmission is under way.  The flag is to protect the
258	 * device's transmitter, not the method itself.  The output
259	 * queue is locked and several threads can process it in
260	 * parallel safely, so the driver can use other means to
261	 * serialize access to the transmitter.
262	 *
263	 * If using IFF_DRV_OACTIVE, the driver should clear the flag
264	 * not earlier than the current transmission is complete, e.g.,
265	 * upon an interrupt from the device, not just before returning
266	 * from if_start.  This method merely starts the transmission,
267	 * which may proceed asynchronously.
268	 */
269
270	/*
271	 * We loop getting packets from the queue until it's empty.
272	 * A h/w driver would loop until the device can accept more
273	 * data into its buffer, or while there are free transmit
274	 * descriptors, or whatever.
275	 */
276	for (;;) {
277		/*
278		 * Try to dequeue one packet.  Stop if the queue is empty.
279		 * Use IF_DEQUEUE() here if ALTQ(9) support is unneeded.
280		 */
281		IFQ_DEQUEUE(&ifp->if_snd, m);
282		if (m == NULL)
283			break;
284
285		/*
286		 * Let bpf(9) at the packet.
287		 */
288		BPF_MTAP(ifp, m);
289
290		/*
291		 * Update the interface counters.
292		 */
293		ifp->if_obytes += m->m_pkthdr.len;
294		ifp->if_opackets++;
295
296		/*
297		 * Finally, just drop the packet.
298		 * TODO: Reply to ARP requests unless IFF_NOARP is set.
299		 */
300		m_freem(m);
301	}
302
303	/*
304	 * ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
305	 * would be here only if the transmission were synchronous.
306	 */
307}
308
309/*
310 * This function provides handlers for module events, namely load and unload.
311 */
312static int
313edsc_modevent(module_t mod, int type, void *data)
314{
315
316	switch (type) {
317	case MOD_LOAD:
318		/*
319		 * Connect to the network interface cloning framework.
320		 * The last argument is the number of units to be created
321		 * from the outset.  It's also the minimum number of units
322		 * allowed.  We don't want any units created as soon as the
323		 * driver is loaded.
324		 */
325		edsc_cloner = if_clone_simple(edscname, edsc_clone_create,
326		    edsc_clone_destroy, 0);
327		break;
328
329	case MOD_UNLOAD:
330		/*
331		 * Disconnect from the cloning framework.
332		 * Existing interfaces will be disposed of properly.
333		 */
334		if_clone_detach(edsc_cloner);
335		break;
336
337	default:
338		/*
339		 * There are other event types, but we don't handle them.
340		 * See module(9).
341		 */
342		return (EOPNOTSUPP);
343	}
344	return (0);
345}
346
347static moduledata_t edsc_mod = {
348	"if_edsc",			/* name */
349	edsc_modevent,			/* event handler */
350	NULL				/* additional data */
351};
352
353DECLARE_MODULE(if_edsc, edsc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
354