FreeBSD/Linux Kernel Cross Reference
sys/net/if_edsc.c
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
54 static const char edscname[] = "edsc";
55
56 /*
57 * Software configuration of an interface specific to this device type.
58 */
59 struct 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 */
71 static struct if_clone *edsc_cloner;
72 static int edsc_clone_create(struct if_clone *, int, caddr_t);
73 static void edsc_clone_destroy(struct ifnet *);
74
75 /*
76 * Interface driver methods.
77 */
78 static void edsc_init(void *dummy);
79 /* static void edsc_input(struct ifnet *ifp, struct mbuf *m); would be here */
80 static int edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
81 static void edsc_start(struct ifnet *ifp);
82
83 /*
84 * We'll allocate softc instances from this.
85 */
86 static MALLOC_DEFINE(M_EDSC, edscname, "Ethernet discard interface");
87
88 /*
89 * Create an interface instance.
90 */
91 static int
92 edsc_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 */
165 static void
166 edsc_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 */
186 static void
187 edsc_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 */
200 static int
201 edsc_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 */
245 static void
246 edsc_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 */
312 static int
313 edsc_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
347 static moduledata_t edsc_mod = {
348 "if_edsc", /* name */
349 edsc_modevent, /* event handler */
350 NULL /* additional data */
351 };
352
353 DECLARE_MODULE(if_edsc, edsc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
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