if_shmem.c revision 1.1
1 /* $NetBSD: if_shmem.c,v 1.1 2009/02/28 15:28:46 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 1.1 2009/02/28 15:28:46 pooka Exp $"); 32 33 #include <sys/param.h> 34 #include <sys/condvar.h> 35 #include <sys/fcntl.h> 36 #include <sys/kmem.h> 37 #include <sys/kthread.h> 38 #include <sys/lock.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 51 /* 52 * A virtual ethernet interface which uses shared memory from a 53 * memory mapped file as the bus. 54 */ 55 56 static int shmif_init(struct ifnet *); 57 static int shmif_ioctl(struct ifnet *, u_long, void *); 58 static void shmif_start(struct ifnet *); 59 static void shmif_stop(struct ifnet *, int); 60 61 struct shmif_sc { 62 struct ethercom sc_ec; 63 uint8_t sc_myaddr[6]; 64 uint8_t *sc_busmem; 65 int sc_memfd; 66 int sc_kq; 67 68 uint32_t sc_nextpacket; 69 uint32_t sc_prevgen; 70 }; 71 #define IFMEM_LOCK (0) 72 #define IFMEM_GENERATION (8) 73 #define IFMEM_LASTPACKET (12) 74 #define IFMEM_WAKEUP (16) 75 #define IFMEM_DATA (20) 76 77 #define BUSCTRL_ATOFF(sc, off) ((uint32_t *)(sc->sc_busmem+(off))) 78 79 #define BUSMEM_SIZE 65536 /* enough? */ 80 81 static void shmif_rcv(void *); 82 83 static uint32_t numif; 84 85 static void 86 lockbus(struct shmif_sc *sc) 87 { 88 89 __cpu_simple_lock((__cpu_simple_lock_t *)sc->sc_busmem); 90 } 91 92 static void 93 unlockbus(struct shmif_sc *sc) 94 { 95 96 __cpu_simple_unlock((__cpu_simple_lock_t *)sc->sc_busmem); 97 } 98 99 static uint32_t 100 busread(struct shmif_sc *sc, void *dest, uint32_t off, size_t len) 101 { 102 size_t chunk; 103 104 KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE); 105 chunk = MIN(len, BUSMEM_SIZE - off); 106 memcpy(dest, sc->sc_busmem + off, chunk); 107 len -= chunk; 108 109 if (len == 0) 110 return off + chunk; 111 112 /* else, wraps around */ 113 off = IFMEM_DATA; 114 sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION); 115 116 /* finish reading */ 117 memcpy((uint8_t *)dest + chunk, sc->sc_busmem + off, len); 118 return off + len; 119 } 120 121 static uint32_t 122 buswrite(struct shmif_sc *sc, uint32_t off, void *data, size_t len) 123 { 124 size_t chunk; 125 126 KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE); 127 128 chunk = MIN(len, BUSMEM_SIZE - off); 129 memcpy(sc->sc_busmem + off, data, chunk); 130 len -= chunk; 131 132 if (len == 0) 133 return off + chunk; 134 135 DPRINTF(("buswrite wrap: wrote %d bytes to %d, left %d to %d", 136 chunk, off, len, IFMEM_DATA)); 137 138 /* else, wraps around */ 139 off = IFMEM_DATA; 140 (*BUSCTRL_ATOFF(sc, IFMEM_GENERATION))++; 141 sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION); 142 143 /* finish writing */ 144 memcpy(sc->sc_busmem + off, (uint8_t *)data + chunk, len); 145 return off + len; 146 } 147 148 static inline uint32_t 149 advance(uint32_t oldoff, uint32_t delta) 150 { 151 uint32_t newoff; 152 153 newoff = oldoff + delta; 154 if (newoff >= BUSMEM_SIZE) 155 newoff -= (BUSMEM_SIZE - IFMEM_DATA); 156 return newoff; 157 158 } 159 160 static uint32_t 161 nextpktoff(struct shmif_sc *sc, uint32_t oldoff) 162 { 163 uint32_t oldlen; 164 165 busread(sc, &oldlen, oldoff, 4); 166 KASSERT(oldlen < BUSMEM_SIZE - IFMEM_DATA); 167 168 return advance(oldoff, 4 + oldlen); 169 } 170 171 int rump_shmif_create(const char *, int *); /* XXX */ 172 173 int 174 rump_shmif_create(const char *path, int *ifnum) 175 { 176 struct shmif_sc *sc; 177 struct ifnet *ifp; 178 uint8_t enaddr[ETHER_ADDR_LEN] = { 0xb2, 0xa0, 0x00, 0x00, 0x00, 0x00 }; 179 uint32_t randnum; 180 unsigned mynum; 181 int error; 182 183 randnum = arc4random(); 184 memcpy(&enaddr[2], &randnum, 4); 185 mynum = atomic_inc_uint_nv(&numif)-1; 186 187 sc = kmem_zalloc(sizeof(*sc), KM_SLEEP); 188 ifp = &sc->sc_ec.ec_if; 189 memcpy(sc->sc_myaddr, enaddr, sizeof(enaddr)); 190 191 sc->sc_memfd = rumpuser_open(path, O_RDWR | O_CREAT, &error); 192 if (sc->sc_memfd == -1) 193 goto fail; 194 sc->sc_busmem = rumpuser_filemmap(sc->sc_memfd, 0, BUSMEM_SIZE, 195 1, 1, &error); 196 if (error) 197 goto fail; 198 199 lockbus(sc); 200 if (*BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) == 0) 201 *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = IFMEM_DATA; 202 sc->sc_nextpacket = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET); 203 sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION); 204 unlockbus(sc); 205 206 sc->sc_kq = rumpuser_writewatchfile_setup(-1, sc->sc_memfd, 0, &error); 207 if (sc->sc_kq == -1) 208 goto fail; 209 210 if (rump_threads) { 211 error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, 212 shmif_rcv, ifp, NULL, "shmif"); 213 if (error) { 214 goto fail; 215 } 216 } else { 217 printf("WARNING: threads not enabled, shmif NOT working\n"); 218 } 219 220 sprintf(ifp->if_xname, "shmif%d", mynum); 221 ifp->if_softc = sc; 222 ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST; 223 ifp->if_init = shmif_init; 224 ifp->if_ioctl = shmif_ioctl; 225 ifp->if_start = shmif_start; 226 ifp->if_stop = shmif_stop; 227 ifp->if_mtu = 1518; 228 229 if_attach(ifp); 230 ether_ifattach(ifp, enaddr); 231 232 *ifnum = mynum; 233 return 0; 234 235 fail: 236 panic("rump_shmemif_create: fixme"); 237 } 238 239 static int 240 shmif_init(struct ifnet *ifp) 241 { 242 243 ifp->if_flags |= IFF_RUNNING; 244 return 0; 245 } 246 247 static int 248 shmif_ioctl(struct ifnet *ifp, u_long cmd, void *data) 249 { 250 int s, rv; 251 252 s = splnet(); 253 rv = ether_ioctl(ifp, cmd, data); 254 splx(s); 255 256 return rv; 257 } 258 259 /* send everything in-context */ 260 static void 261 shmif_start(struct ifnet *ifp) 262 { 263 struct shmif_sc *sc = ifp->if_softc; 264 struct mbuf *m, *m0; 265 uint32_t lastoff, dataoff, npktlenoff; 266 uint32_t pktsize = 0; 267 bool wrote = false; 268 int error; 269 270 for (;;) { 271 IF_DEQUEUE(&ifp->if_snd, m0); 272 if (m0 == NULL) { 273 break; 274 } 275 276 lockbus(sc); 277 lastoff = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET); 278 279 npktlenoff = nextpktoff(sc, lastoff); 280 dataoff = advance(npktlenoff, 4); 281 282 for (m = m0; m != NULL; m = m->m_next) { 283 pktsize += m->m_len; 284 dataoff = buswrite(sc, dataoff, mtod(m, void *), 285 m->m_len); 286 } 287 buswrite(sc, npktlenoff, &pktsize, 4); 288 *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = npktlenoff; 289 unlockbus(sc); 290 291 m_freem(m0); 292 wrote = true; 293 294 DPRINTF(("shmif_start: send %d bytes at off %d\n", 295 pktsize, npktlenoff)); 296 } 297 /* wakeup */ 298 if (wrote) 299 rumpuser_pwrite(sc->sc_memfd, &error, 4, IFMEM_WAKEUP, &error); 300 } 301 302 static void 303 shmif_stop(struct ifnet *ifp, int disable) 304 { 305 306 panic("%s: unimpl", __func__); 307 } 308 309 static void 310 shmif_rcv(void *arg) 311 { 312 struct ifnet *ifp = arg; 313 struct shmif_sc *sc = ifp->if_softc; 314 struct mbuf *m = NULL; 315 struct ether_header *eth; 316 uint32_t nextpkt, pktlen, lastpkt, busgen, lastnext; 317 int error; 318 319 for (;;) { 320 if (m == NULL) { 321 m = m_gethdr(M_WAIT, MT_DATA); 322 MCLGET(m, M_WAIT); 323 } 324 325 DPRINTF(("waiting %d/%d\n", sc->sc_nextpacket, sc->sc_prevgen)); 326 327 KASSERT(m->m_flags & M_EXT); 328 lockbus(sc); 329 lastpkt = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET); 330 busgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION); 331 lastnext = nextpktoff(sc, lastpkt); 332 if ((lastnext > sc->sc_nextpacket && busgen > sc->sc_prevgen) 333 || (busgen > sc->sc_prevgen+1)) { 334 nextpkt = lastpkt; 335 sc->sc_prevgen = busgen; 336 printf("DROPPING\n"); 337 } else { 338 nextpkt = sc->sc_nextpacket; 339 } 340 341 /* need more data? */ 342 if (lastnext == nextpkt && sc->sc_prevgen == busgen){ 343 unlockbus(sc); 344 error = 0; 345 rumpuser_writewatchfile_wait(sc->sc_kq, NULL, &error); 346 if (__predict_false(error)) 347 printf("shmif_rcv: wait failed %d\n", error); 348 continue; 349 } 350 351 busread(sc, &pktlen, nextpkt, 4); 352 busread(sc, mtod(m, void *), advance(nextpkt, 4), pktlen); 353 354 DPRINTF(("shmif_rcv: read packet of length %d at %d\n", 355 pktlen, nextpkt)); 356 357 sc->sc_nextpacket = nextpktoff(sc, nextpkt); 358 sc->sc_prevgen = busgen; 359 unlockbus(sc); 360 361 m->m_len = m->m_pkthdr.len = pktlen; 362 m->m_pkthdr.rcvif = ifp; 363 364 /* if it's to us, don't pass up and reuse storage space */ 365 eth = mtod(m, struct ether_header *); 366 if (memcmp(eth->ether_shost, sc->sc_myaddr, 6) != 0) { 367 ifp->if_input(ifp, m); 368 m = NULL; 369 } 370 } 371 372 panic("shmif_worker is a lazy boy %d\n", error); 373 } 374
Indexes created Tue Sep 23 02:09:52 GMT 2025