if_shmem.c revision 1.2 1 1.2 pooka /* $NetBSD: if_shmem.c,v 1.2 2009/02/28 16:15:19 pooka Exp $ */
2 1.1 pooka
3 1.1 pooka /*
4 1.1 pooka * Copyright (c) 2009 Antti Kantee. All Rights Reserved.
5 1.1 pooka *
6 1.1 pooka * Development of this software was supported by The Nokia Foundation.
7 1.1 pooka *
8 1.1 pooka * Redistribution and use in source and binary forms, with or without
9 1.1 pooka * modification, are permitted provided that the following conditions
10 1.1 pooka * are met:
11 1.1 pooka * 1. Redistributions of source code must retain the above copyright
12 1.1 pooka * notice, this list of conditions and the following disclaimer.
13 1.1 pooka * 2. Redistributions in binary form must reproduce the above copyright
14 1.1 pooka * notice, this list of conditions and the following disclaimer in the
15 1.1 pooka * documentation and/or other materials provided with the distribution.
16 1.1 pooka *
17 1.1 pooka * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
18 1.1 pooka * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 1.1 pooka * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 1.1 pooka * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 1.1 pooka * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 1.1 pooka * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23 1.1 pooka * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 1.1 pooka * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 1.1 pooka * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 1.1 pooka * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 1.1 pooka * SUCH DAMAGE.
28 1.1 pooka */
29 1.1 pooka
30 1.1 pooka #include <sys/cdefs.h>
31 1.2 pooka __KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.2 2009/02/28 16:15:19 pooka Exp $");
32 1.1 pooka
33 1.1 pooka #include <sys/param.h>
34 1.1 pooka #include <sys/condvar.h>
35 1.1 pooka #include <sys/fcntl.h>
36 1.1 pooka #include <sys/kmem.h>
37 1.1 pooka #include <sys/kthread.h>
38 1.1 pooka #include <sys/lock.h>
39 1.1 pooka
40 1.1 pooka #include <net/if.h>
41 1.1 pooka #include <net/if_ether.h>
42 1.1 pooka
43 1.1 pooka #include <netinet/in.h>
44 1.1 pooka #include <netinet/in_var.h>
45 1.1 pooka
46 1.1 pooka #include <rump/rump.h>
47 1.1 pooka #include <rump/rumpuser.h>
48 1.1 pooka
49 1.1 pooka #include "rump_private.h"
50 1.1 pooka
51 1.1 pooka /*
52 1.1 pooka * A virtual ethernet interface which uses shared memory from a
53 1.1 pooka * memory mapped file as the bus.
54 1.1 pooka */
55 1.1 pooka
56 1.1 pooka static int shmif_init(struct ifnet *);
57 1.1 pooka static int shmif_ioctl(struct ifnet *, u_long, void *);
58 1.1 pooka static void shmif_start(struct ifnet *);
59 1.1 pooka static void shmif_stop(struct ifnet *, int);
60 1.1 pooka
61 1.1 pooka struct shmif_sc {
62 1.1 pooka struct ethercom sc_ec;
63 1.1 pooka uint8_t sc_myaddr[6];
64 1.1 pooka uint8_t *sc_busmem;
65 1.1 pooka int sc_memfd;
66 1.1 pooka int sc_kq;
67 1.1 pooka
68 1.1 pooka uint32_t sc_nextpacket;
69 1.1 pooka uint32_t sc_prevgen;
70 1.1 pooka };
71 1.1 pooka #define IFMEM_LOCK (0)
72 1.1 pooka #define IFMEM_GENERATION (8)
73 1.1 pooka #define IFMEM_LASTPACKET (12)
74 1.1 pooka #define IFMEM_WAKEUP (16)
75 1.1 pooka #define IFMEM_DATA (20)
76 1.1 pooka
77 1.1 pooka #define BUSCTRL_ATOFF(sc, off) ((uint32_t *)(sc->sc_busmem+(off)))
78 1.1 pooka
79 1.1 pooka #define BUSMEM_SIZE 65536 /* enough? */
80 1.1 pooka
81 1.1 pooka static void shmif_rcv(void *);
82 1.1 pooka
83 1.1 pooka static uint32_t numif;
84 1.1 pooka
85 1.2 pooka /*
86 1.2 pooka * This locking needs work and will misbehave severely if:
87 1.2 pooka * 1) the backing memory has to be paged in
88 1.2 pooka * 2) some lockholder exits while holding the lock
89 1.2 pooka */
90 1.1 pooka static void
91 1.1 pooka lockbus(struct shmif_sc *sc)
92 1.1 pooka {
93 1.1 pooka
94 1.1 pooka __cpu_simple_lock((__cpu_simple_lock_t *)sc->sc_busmem);
95 1.1 pooka }
96 1.1 pooka
97 1.1 pooka static void
98 1.1 pooka unlockbus(struct shmif_sc *sc)
99 1.1 pooka {
100 1.1 pooka
101 1.1 pooka __cpu_simple_unlock((__cpu_simple_lock_t *)sc->sc_busmem);
102 1.1 pooka }
103 1.1 pooka
104 1.1 pooka static uint32_t
105 1.1 pooka busread(struct shmif_sc *sc, void *dest, uint32_t off, size_t len)
106 1.1 pooka {
107 1.1 pooka size_t chunk;
108 1.1 pooka
109 1.1 pooka KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE);
110 1.1 pooka chunk = MIN(len, BUSMEM_SIZE - off);
111 1.1 pooka memcpy(dest, sc->sc_busmem + off, chunk);
112 1.1 pooka len -= chunk;
113 1.1 pooka
114 1.1 pooka if (len == 0)
115 1.1 pooka return off + chunk;
116 1.1 pooka
117 1.1 pooka /* else, wraps around */
118 1.1 pooka off = IFMEM_DATA;
119 1.1 pooka sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
120 1.1 pooka
121 1.1 pooka /* finish reading */
122 1.1 pooka memcpy((uint8_t *)dest + chunk, sc->sc_busmem + off, len);
123 1.1 pooka return off + len;
124 1.1 pooka }
125 1.1 pooka
126 1.1 pooka static uint32_t
127 1.1 pooka buswrite(struct shmif_sc *sc, uint32_t off, void *data, size_t len)
128 1.1 pooka {
129 1.1 pooka size_t chunk;
130 1.1 pooka
131 1.1 pooka KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE);
132 1.1 pooka
133 1.1 pooka chunk = MIN(len, BUSMEM_SIZE - off);
134 1.1 pooka memcpy(sc->sc_busmem + off, data, chunk);
135 1.1 pooka len -= chunk;
136 1.1 pooka
137 1.1 pooka if (len == 0)
138 1.1 pooka return off + chunk;
139 1.1 pooka
140 1.1 pooka DPRINTF(("buswrite wrap: wrote %d bytes to %d, left %d to %d",
141 1.1 pooka chunk, off, len, IFMEM_DATA));
142 1.1 pooka
143 1.1 pooka /* else, wraps around */
144 1.1 pooka off = IFMEM_DATA;
145 1.1 pooka (*BUSCTRL_ATOFF(sc, IFMEM_GENERATION))++;
146 1.1 pooka sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
147 1.1 pooka
148 1.1 pooka /* finish writing */
149 1.1 pooka memcpy(sc->sc_busmem + off, (uint8_t *)data + chunk, len);
150 1.1 pooka return off + len;
151 1.1 pooka }
152 1.1 pooka
153 1.1 pooka static inline uint32_t
154 1.1 pooka advance(uint32_t oldoff, uint32_t delta)
155 1.1 pooka {
156 1.1 pooka uint32_t newoff;
157 1.1 pooka
158 1.1 pooka newoff = oldoff + delta;
159 1.1 pooka if (newoff >= BUSMEM_SIZE)
160 1.1 pooka newoff -= (BUSMEM_SIZE - IFMEM_DATA);
161 1.1 pooka return newoff;
162 1.1 pooka
163 1.1 pooka }
164 1.1 pooka
165 1.1 pooka static uint32_t
166 1.1 pooka nextpktoff(struct shmif_sc *sc, uint32_t oldoff)
167 1.1 pooka {
168 1.1 pooka uint32_t oldlen;
169 1.1 pooka
170 1.1 pooka busread(sc, &oldlen, oldoff, 4);
171 1.1 pooka KASSERT(oldlen < BUSMEM_SIZE - IFMEM_DATA);
172 1.1 pooka
173 1.1 pooka return advance(oldoff, 4 + oldlen);
174 1.1 pooka }
175 1.1 pooka
176 1.1 pooka int rump_shmif_create(const char *, int *); /* XXX */
177 1.1 pooka
178 1.1 pooka int
179 1.1 pooka rump_shmif_create(const char *path, int *ifnum)
180 1.1 pooka {
181 1.1 pooka struct shmif_sc *sc;
182 1.1 pooka struct ifnet *ifp;
183 1.1 pooka uint8_t enaddr[ETHER_ADDR_LEN] = { 0xb2, 0xa0, 0x00, 0x00, 0x00, 0x00 };
184 1.1 pooka uint32_t randnum;
185 1.1 pooka unsigned mynum;
186 1.1 pooka int error;
187 1.1 pooka
188 1.1 pooka randnum = arc4random();
189 1.1 pooka memcpy(&enaddr[2], &randnum, 4);
190 1.1 pooka mynum = atomic_inc_uint_nv(&numif)-1;
191 1.1 pooka
192 1.1 pooka sc = kmem_zalloc(sizeof(*sc), KM_SLEEP);
193 1.1 pooka ifp = &sc->sc_ec.ec_if;
194 1.1 pooka memcpy(sc->sc_myaddr, enaddr, sizeof(enaddr));
195 1.1 pooka
196 1.1 pooka sc->sc_memfd = rumpuser_open(path, O_RDWR | O_CREAT, &error);
197 1.1 pooka if (sc->sc_memfd == -1)
198 1.1 pooka goto fail;
199 1.1 pooka sc->sc_busmem = rumpuser_filemmap(sc->sc_memfd, 0, BUSMEM_SIZE,
200 1.1 pooka 1, 1, &error);
201 1.1 pooka if (error)
202 1.1 pooka goto fail;
203 1.1 pooka
204 1.1 pooka lockbus(sc);
205 1.1 pooka if (*BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) == 0)
206 1.1 pooka *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = IFMEM_DATA;
207 1.1 pooka sc->sc_nextpacket = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET);
208 1.1 pooka sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
209 1.1 pooka unlockbus(sc);
210 1.1 pooka
211 1.1 pooka sc->sc_kq = rumpuser_writewatchfile_setup(-1, sc->sc_memfd, 0, &error);
212 1.1 pooka if (sc->sc_kq == -1)
213 1.1 pooka goto fail;
214 1.1 pooka
215 1.1 pooka if (rump_threads) {
216 1.1 pooka error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL,
217 1.1 pooka shmif_rcv, ifp, NULL, "shmif");
218 1.1 pooka if (error) {
219 1.1 pooka goto fail;
220 1.1 pooka }
221 1.1 pooka } else {
222 1.1 pooka printf("WARNING: threads not enabled, shmif NOT working\n");
223 1.1 pooka }
224 1.1 pooka
225 1.1 pooka sprintf(ifp->if_xname, "shmif%d", mynum);
226 1.1 pooka ifp->if_softc = sc;
227 1.1 pooka ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
228 1.1 pooka ifp->if_init = shmif_init;
229 1.1 pooka ifp->if_ioctl = shmif_ioctl;
230 1.1 pooka ifp->if_start = shmif_start;
231 1.1 pooka ifp->if_stop = shmif_stop;
232 1.1 pooka ifp->if_mtu = 1518;
233 1.1 pooka
234 1.1 pooka if_attach(ifp);
235 1.1 pooka ether_ifattach(ifp, enaddr);
236 1.1 pooka
237 1.2 pooka if (ifnum)
238 1.2 pooka *ifnum = mynum;
239 1.1 pooka return 0;
240 1.1 pooka
241 1.1 pooka fail:
242 1.1 pooka panic("rump_shmemif_create: fixme");
243 1.1 pooka }
244 1.1 pooka
245 1.1 pooka static int
246 1.1 pooka shmif_init(struct ifnet *ifp)
247 1.1 pooka {
248 1.1 pooka
249 1.1 pooka ifp->if_flags |= IFF_RUNNING;
250 1.1 pooka return 0;
251 1.1 pooka }
252 1.1 pooka
253 1.1 pooka static int
254 1.1 pooka shmif_ioctl(struct ifnet *ifp, u_long cmd, void *data)
255 1.1 pooka {
256 1.1 pooka int s, rv;
257 1.1 pooka
258 1.1 pooka s = splnet();
259 1.1 pooka rv = ether_ioctl(ifp, cmd, data);
260 1.1 pooka splx(s);
261 1.1 pooka
262 1.1 pooka return rv;
263 1.1 pooka }
264 1.1 pooka
265 1.1 pooka /* send everything in-context */
266 1.1 pooka static void
267 1.1 pooka shmif_start(struct ifnet *ifp)
268 1.1 pooka {
269 1.1 pooka struct shmif_sc *sc = ifp->if_softc;
270 1.1 pooka struct mbuf *m, *m0;
271 1.1 pooka uint32_t lastoff, dataoff, npktlenoff;
272 1.1 pooka uint32_t pktsize = 0;
273 1.1 pooka bool wrote = false;
274 1.1 pooka int error;
275 1.1 pooka
276 1.1 pooka for (;;) {
277 1.1 pooka IF_DEQUEUE(&ifp->if_snd, m0);
278 1.1 pooka if (m0 == NULL) {
279 1.1 pooka break;
280 1.1 pooka }
281 1.1 pooka
282 1.1 pooka lockbus(sc);
283 1.1 pooka lastoff = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET);
284 1.1 pooka
285 1.1 pooka npktlenoff = nextpktoff(sc, lastoff);
286 1.1 pooka dataoff = advance(npktlenoff, 4);
287 1.1 pooka
288 1.1 pooka for (m = m0; m != NULL; m = m->m_next) {
289 1.1 pooka pktsize += m->m_len;
290 1.1 pooka dataoff = buswrite(sc, dataoff, mtod(m, void *),
291 1.1 pooka m->m_len);
292 1.1 pooka }
293 1.1 pooka buswrite(sc, npktlenoff, &pktsize, 4);
294 1.1 pooka *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = npktlenoff;
295 1.1 pooka unlockbus(sc);
296 1.1 pooka
297 1.1 pooka m_freem(m0);
298 1.1 pooka wrote = true;
299 1.1 pooka
300 1.1 pooka DPRINTF(("shmif_start: send %d bytes at off %d\n",
301 1.1 pooka pktsize, npktlenoff));
302 1.1 pooka }
303 1.1 pooka /* wakeup */
304 1.1 pooka if (wrote)
305 1.1 pooka rumpuser_pwrite(sc->sc_memfd, &error, 4, IFMEM_WAKEUP, &error);
306 1.1 pooka }
307 1.1 pooka
308 1.1 pooka static void
309 1.1 pooka shmif_stop(struct ifnet *ifp, int disable)
310 1.1 pooka {
311 1.1 pooka
312 1.1 pooka panic("%s: unimpl", __func__);
313 1.1 pooka }
314 1.1 pooka
315 1.1 pooka static void
316 1.1 pooka shmif_rcv(void *arg)
317 1.1 pooka {
318 1.1 pooka struct ifnet *ifp = arg;
319 1.1 pooka struct shmif_sc *sc = ifp->if_softc;
320 1.1 pooka struct mbuf *m = NULL;
321 1.1 pooka struct ether_header *eth;
322 1.1 pooka uint32_t nextpkt, pktlen, lastpkt, busgen, lastnext;
323 1.1 pooka int error;
324 1.1 pooka
325 1.1 pooka for (;;) {
326 1.1 pooka if (m == NULL) {
327 1.1 pooka m = m_gethdr(M_WAIT, MT_DATA);
328 1.1 pooka MCLGET(m, M_WAIT);
329 1.1 pooka }
330 1.1 pooka
331 1.1 pooka DPRINTF(("waiting %d/%d\n", sc->sc_nextpacket, sc->sc_prevgen));
332 1.1 pooka
333 1.1 pooka KASSERT(m->m_flags & M_EXT);
334 1.1 pooka lockbus(sc);
335 1.1 pooka lastpkt = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET);
336 1.1 pooka busgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
337 1.1 pooka lastnext = nextpktoff(sc, lastpkt);
338 1.1 pooka if ((lastnext > sc->sc_nextpacket && busgen > sc->sc_prevgen)
339 1.1 pooka || (busgen > sc->sc_prevgen+1)) {
340 1.1 pooka nextpkt = lastpkt;
341 1.1 pooka sc->sc_prevgen = busgen;
342 1.1 pooka printf("DROPPING\n");
343 1.1 pooka } else {
344 1.1 pooka nextpkt = sc->sc_nextpacket;
345 1.1 pooka }
346 1.1 pooka
347 1.1 pooka /* need more data? */
348 1.1 pooka if (lastnext == nextpkt && sc->sc_prevgen == busgen){
349 1.1 pooka unlockbus(sc);
350 1.1 pooka error = 0;
351 1.1 pooka rumpuser_writewatchfile_wait(sc->sc_kq, NULL, &error);
352 1.1 pooka if (__predict_false(error))
353 1.1 pooka printf("shmif_rcv: wait failed %d\n", error);
354 1.1 pooka continue;
355 1.1 pooka }
356 1.1 pooka
357 1.1 pooka busread(sc, &pktlen, nextpkt, 4);
358 1.1 pooka busread(sc, mtod(m, void *), advance(nextpkt, 4), pktlen);
359 1.1 pooka
360 1.1 pooka DPRINTF(("shmif_rcv: read packet of length %d at %d\n",
361 1.1 pooka pktlen, nextpkt));
362 1.1 pooka
363 1.1 pooka sc->sc_nextpacket = nextpktoff(sc, nextpkt);
364 1.1 pooka sc->sc_prevgen = busgen;
365 1.1 pooka unlockbus(sc);
366 1.1 pooka
367 1.1 pooka m->m_len = m->m_pkthdr.len = pktlen;
368 1.1 pooka m->m_pkthdr.rcvif = ifp;
369 1.1 pooka
370 1.1 pooka /* if it's to us, don't pass up and reuse storage space */
371 1.1 pooka eth = mtod(m, struct ether_header *);
372 1.1 pooka if (memcmp(eth->ether_shost, sc->sc_myaddr, 6) != 0) {
373 1.1 pooka ifp->if_input(ifp, m);
374 1.1 pooka m = NULL;
375 1.1 pooka }
376 1.1 pooka }
377 1.1 pooka
378 1.1 pooka panic("shmif_worker is a lazy boy %d\n", error);
379 1.1 pooka }
380