if_shmem.c revision 1.9
1 /* $NetBSD: if_shmem.c,v 1.9 2009/10/20 23:29:57 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 2009 Antti Kantee. All Rights Reserved. 5 * 6 * Development of this software was supported by The Nokia Foundation. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 18 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 20 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR 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 OR 23 * 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 30 #include <sys/cdefs.h> 31 __KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.9 2009/10/20 23:29:57 pooka Exp $"); 32 33 #include <sys/param.h> 34 #include <sys/fcntl.h> 35 #include <sys/kmem.h> 36 #include <sys/kthread.h> 37 #include <sys/lock.h> 38 #include <sys/atomic.h> 39 40 #include <net/if.h> 41 #include <net/if_ether.h> 42 43 #include <netinet/in.h> 44 #include <netinet/in_var.h> 45 46 #include <rump/rump.h> 47 #include <rump/rumpuser.h> 48 49 #include "rump_private.h" 50 #include "rump_net_private.h" 51 52 #if 0 53 #define DPRINTF(x) rumpuser_dprintf x 54 #else 55 #define DPRINTF(x) 56 #endif 57 58 /* 59 * A virtual ethernet interface which uses shared memory from a 60 * memory mapped file as the bus. 61 */ 62 63 static int shmif_init(struct ifnet *); 64 static int shmif_ioctl(struct ifnet *, u_long, void *); 65 static void shmif_start(struct ifnet *); 66 static void shmif_stop(struct ifnet *, int); 67 68 struct shmif_sc { 69 struct ethercom sc_ec; 70 uint8_t sc_myaddr[6]; 71 uint8_t *sc_busmem; 72 int sc_memfd; 73 int sc_kq; 74 75 uint32_t sc_nextpacket; 76 uint32_t sc_prevgen; 77 }; 78 #define IFMEM_LOCK (0) 79 #define IFMEM_GENERATION (8) 80 #define IFMEM_LASTPACKET (12) 81 #define IFMEM_WAKEUP (16) 82 #define IFMEM_DATA (20) 83 84 #define BUSCTRL_ATOFF(sc, off) ((uint32_t *)(sc->sc_busmem+(off))) 85 86 #define BUSMEM_SIZE 65536 /* enough? */ 87 88 static void shmif_rcv(void *); 89 90 static uint32_t numif; 91 92 /* 93 * This locking needs work and will misbehave severely if: 94 * 1) the backing memory has to be paged in 95 * 2) some lockholder exits while holding the lock 96 */ 97 static void 98 lockbus(struct shmif_sc *sc) 99 { 100 101 __cpu_simple_lock((__cpu_simple_lock_t *)sc->sc_busmem); 102 } 103 104 static void 105 unlockbus(struct shmif_sc *sc) 106 { 107 108 __cpu_simple_unlock((__cpu_simple_lock_t *)sc->sc_busmem); 109 } 110 111 static uint32_t 112 busread(struct shmif_sc *sc, void *dest, uint32_t off, size_t len) 113 { 114 size_t chunk; 115 116 KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE); 117 chunk = MIN(len, BUSMEM_SIZE - off); 118 memcpy(dest, sc->sc_busmem + off, chunk); 119 len -= chunk; 120 121 if (len == 0) 122 return off + chunk; 123 124 /* else, wraps around */ 125 off = IFMEM_DATA; 126 sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION); 127 128 /* finish reading */ 129 memcpy((uint8_t *)dest + chunk, sc->sc_busmem + off, len); 130 return off + len; 131 } 132 133 static uint32_t 134 buswrite(struct shmif_sc *sc, uint32_t off, void *data, size_t len) 135 { 136 size_t chunk; 137 138 KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE); 139 140 chunk = MIN(len, BUSMEM_SIZE - off); 141 memcpy(sc->sc_busmem + off, data, chunk); 142 len -= chunk; 143 144 if (len == 0) 145 return off + chunk; 146 147 DPRINTF(("buswrite wrap: wrote %d bytes to %d, left %d to %d", 148 chunk, off, len, IFMEM_DATA)); 149 150 /* else, wraps around */ 151 off = IFMEM_DATA; 152 (*BUSCTRL_ATOFF(sc, IFMEM_GENERATION))++; 153 sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION); 154 155 /* finish writing */ 156 memcpy(sc->sc_busmem + off, (uint8_t *)data + chunk, len); 157 return off + len; 158 } 159 160 static inline uint32_t 161 advance(uint32_t oldoff, uint32_t delta) 162 { 163 uint32_t newoff; 164 165 newoff = oldoff + delta; 166 if (newoff >= BUSMEM_SIZE) 167 newoff -= (BUSMEM_SIZE - IFMEM_DATA); 168 return newoff; 169 170 } 171 172 static uint32_t 173 nextpktoff(struct shmif_sc *sc, uint32_t oldoff) 174 { 175 uint32_t oldlen; 176 177 busread(sc, &oldlen, oldoff, 4); 178 KASSERT(oldlen < BUSMEM_SIZE - IFMEM_DATA); 179 180 return advance(oldoff, 4 + oldlen); 181 } 182 183 int 184 rump_shmif_create(const char *path, int *ifnum) 185 { 186 struct shmif_sc *sc; 187 struct ifnet *ifp; 188 uint8_t enaddr[ETHER_ADDR_LEN] = { 0xb2, 0xa0, 0x00, 0x00, 0x00, 0x00 }; 189 uint32_t randnum; 190 unsigned mynum; 191 int error; 192 193 randnum = arc4random(); 194 memcpy(&enaddr[2], &randnum, 4); 195 mynum = atomic_inc_uint_nv(&numif)-1; 196 197 sc = kmem_zalloc(sizeof(*sc), KM_SLEEP); 198 ifp = &sc->sc_ec.ec_if; 199 memcpy(sc->sc_myaddr, enaddr, sizeof(enaddr)); 200 201 sc->sc_memfd = rumpuser_open(path, O_RDWR | O_CREAT, &error); 202 if (sc->sc_memfd == -1) 203 goto fail; 204 sc->sc_busmem = rumpuser_filemmap(sc->sc_memfd, 0, BUSMEM_SIZE, 205 RUMPUSER_FILEMMAP_TRUNCATE | RUMPUSER_FILEMMAP_SHARED 206 | RUMPUSER_FILEMMAP_READ | RUMPUSER_FILEMMAP_WRITE, &error); 207 if (error) 208 goto fail; 209 210 lockbus(sc); 211 if (*BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) == 0) 212 *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = IFMEM_DATA; 213 sc->sc_nextpacket = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET); 214 sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION); 215 unlockbus(sc); 216 217 sc->sc_kq = rumpuser_writewatchfile_setup(-1, sc->sc_memfd, 0, &error); 218 if (sc->sc_kq == -1) 219 goto fail; 220 221 sprintf(ifp->if_xname, "shmif%d", mynum); 222 ifp->if_softc = sc; 223 ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST; 224 ifp->if_init = shmif_init; 225 ifp->if_ioctl = shmif_ioctl; 226 ifp->if_start = shmif_start; 227 ifp->if_stop = shmif_stop; 228 ifp->if_mtu = 1518; 229 230 if_attach(ifp); 231 ether_ifattach(ifp, enaddr); 232 233 if (ifnum) 234 *ifnum = mynum; 235 return 0; 236 237 fail: 238 panic("rump_shmemif_create: fixme"); 239 } 240 241 static int 242 shmif_init(struct ifnet *ifp) 243 { 244 int error = 0; 245 246 if (rump_threads) { 247 error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, 248 shmif_rcv, ifp, NULL, "shmif"); 249 } else { 250 printf("WARNING: threads not enabled, shmif NOT working\n"); 251 } 252 253 ifp->if_flags |= IFF_RUNNING; 254 return error; 255 } 256 257 static int 258 shmif_ioctl(struct ifnet *ifp, u_long cmd, void *data) 259 { 260 int s, rv; 261 262 s = splnet(); 263 rv = ether_ioctl(ifp, cmd, data); 264 if (rv == ENETRESET) 265 rv = 0; 266 splx(s); 267 268 return rv; 269 } 270 271 /* send everything in-context */ 272 static void 273 shmif_start(struct ifnet *ifp) 274 { 275 struct shmif_sc *sc = ifp->if_softc; 276 struct mbuf *m, *m0; 277 uint32_t lastoff, dataoff, npktlenoff; 278 uint32_t pktsize = 0; 279 bool wrote = false; 280 int error; 281 282 for (;;) { 283 IF_DEQUEUE(&ifp->if_snd, m0); 284 if (m0 == NULL) { 285 break; 286 } 287 288 lockbus(sc); 289 lastoff = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET); 290 291 npktlenoff = nextpktoff(sc, lastoff); 292 dataoff = advance(npktlenoff, 4); 293 294 for (m = m0; m != NULL; m = m->m_next) { 295 pktsize += m->m_len; 296 dataoff = buswrite(sc, dataoff, mtod(m, void *), 297 m->m_len); 298 } 299 buswrite(sc, npktlenoff, &pktsize, 4); 300 *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = npktlenoff; 301 unlockbus(sc); 302 303 m_freem(m0); 304 wrote = true; 305 306 DPRINTF(("shmif_start: send %d bytes at off %d\n", 307 pktsize, npktlenoff)); 308 } 309 /* wakeup */ 310 if (wrote) 311 rumpuser_pwrite(sc->sc_memfd, &error, 4, IFMEM_WAKEUP, &error); 312 } 313 314 static void 315 shmif_stop(struct ifnet *ifp, int disable) 316 { 317 318 panic("%s: unimpl", __func__); 319 } 320 321 static void 322 shmif_rcv(void *arg) 323 { 324 struct ifnet *ifp = arg; 325 struct shmif_sc *sc = ifp->if_softc; 326 struct mbuf *m = NULL; 327 struct ether_header *eth; 328 uint32_t nextpkt, pktlen, lastpkt, busgen, lastnext; 329 int error; 330 331 for (;;) { 332 if (m == NULL) { 333 m = m_gethdr(M_WAIT, MT_DATA); 334 MCLGET(m, M_WAIT); 335 } 336 337 DPRINTF(("waiting %d/%d\n", sc->sc_nextpacket, sc->sc_prevgen)); 338 339 KASSERT(m->m_flags & M_EXT); 340 lockbus(sc); 341 lastpkt = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET); 342 busgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION); 343 lastnext = nextpktoff(sc, lastpkt); 344 if ((lastnext > sc->sc_nextpacket && busgen > sc->sc_prevgen) 345 || (busgen > sc->sc_prevgen+1)) { 346 nextpkt = lastpkt; 347 sc->sc_prevgen = busgen; 348 rumpuser_dprintf("DROPPING\n"); 349 } else { 350 nextpkt = sc->sc_nextpacket; 351 } 352 353 /* need more data? */ 354 if (lastnext == nextpkt && sc->sc_prevgen == busgen){ 355 unlockbus(sc); 356 error = 0; 357 rumpuser_writewatchfile_wait(sc->sc_kq, NULL, &error); 358 if (__predict_false(error)) 359 printf("shmif_rcv: wait failed %d\n", error); 360 continue; 361 } 362 363 busread(sc, &pktlen, nextpkt, 4); 364 busread(sc, mtod(m, void *), advance(nextpkt, 4), pktlen); 365 366 DPRINTF(("shmif_rcv: read packet of length %d at %d\n", 367 pktlen, nextpkt)); 368 369 sc->sc_nextpacket = nextpktoff(sc, nextpkt); 370 sc->sc_prevgen = busgen; 371 unlockbus(sc); 372 373 m->m_len = m->m_pkthdr.len = pktlen; 374 m->m_pkthdr.rcvif = ifp; 375 376 /* if it's to us, don't pass up and reuse storage space */ 377 eth = mtod(m, struct ether_header *); 378 if (memcmp(eth->ether_shost, sc->sc_myaddr, 6) != 0) { 379 ifp->if_input(ifp, m); 380 m = NULL; 381 } 382 } 383 384 panic("shmif_worker is a lazy boy %d\n", error); 385 } 386
Indexes created Tue Sep 23 07:09:52 GMT 2025