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if_shmem.c revision 1.4.2.3
      1  1.4.2.3  skrll /*	$NetBSD: if_shmem.c,v 1.4.2.3 2009/04/28 07:37:52 skrll Exp $	*/
      2  1.4.2.2  skrll 
      3  1.4.2.2  skrll /*
      4  1.4.2.2  skrll  * Copyright (c) 2009 Antti Kantee.  All Rights Reserved.
      5  1.4.2.2  skrll  *
      6  1.4.2.2  skrll  * Development of this software was supported by The Nokia Foundation.
      7  1.4.2.2  skrll  *
      8  1.4.2.2  skrll  * Redistribution and use in source and binary forms, with or without
      9  1.4.2.2  skrll  * modification, are permitted provided that the following conditions
     10  1.4.2.2  skrll  * are met:
     11  1.4.2.2  skrll  * 1. Redistributions of source code must retain the above copyright
     12  1.4.2.2  skrll  *    notice, this list of conditions and the following disclaimer.
     13  1.4.2.2  skrll  * 2. Redistributions in binary form must reproduce the above copyright
     14  1.4.2.2  skrll  *    notice, this list of conditions and the following disclaimer in the
     15  1.4.2.2  skrll  *    documentation and/or other materials provided with the distribution.
     16  1.4.2.2  skrll  *
     17  1.4.2.2  skrll  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     18  1.4.2.2  skrll  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  1.4.2.2  skrll  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  1.4.2.2  skrll  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     21  1.4.2.2  skrll  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     22  1.4.2.2  skrll  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     23  1.4.2.2  skrll  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     24  1.4.2.2  skrll  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     25  1.4.2.2  skrll  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     26  1.4.2.2  skrll  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     27  1.4.2.2  skrll  * SUCH DAMAGE.
     28  1.4.2.2  skrll  */
     29  1.4.2.2  skrll 
     30  1.4.2.2  skrll #include <sys/cdefs.h>
     31  1.4.2.3  skrll __KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.4.2.3 2009/04/28 07:37:52 skrll Exp $");
     32  1.4.2.2  skrll 
     33  1.4.2.2  skrll #include <sys/param.h>
     34  1.4.2.2  skrll #include <sys/fcntl.h>
     35  1.4.2.2  skrll #include <sys/kmem.h>
     36  1.4.2.2  skrll #include <sys/kthread.h>
     37  1.4.2.2  skrll #include <sys/lock.h>
     38  1.4.2.2  skrll #include <sys/atomic.h>
     39  1.4.2.2  skrll 
     40  1.4.2.2  skrll #include <net/if.h>
     41  1.4.2.2  skrll #include <net/if_ether.h>
     42  1.4.2.2  skrll 
     43  1.4.2.2  skrll #include <netinet/in.h>
     44  1.4.2.2  skrll #include <netinet/in_var.h>
     45  1.4.2.2  skrll 
     46  1.4.2.2  skrll #include <rump/rump.h>
     47  1.4.2.2  skrll #include <rump/rumpuser.h>
     48  1.4.2.2  skrll 
     49  1.4.2.2  skrll #include "rump_private.h"
     50  1.4.2.2  skrll 
     51  1.4.2.3  skrll #if 0
     52  1.4.2.3  skrll #define DPRINTF(x) printf x
     53  1.4.2.3  skrll #else
     54  1.4.2.3  skrll #define DPRINTF(x)
     55  1.4.2.3  skrll #endif
     56  1.4.2.3  skrll 
     57  1.4.2.2  skrll /*
     58  1.4.2.2  skrll  * A virtual ethernet interface which uses shared memory from a
     59  1.4.2.2  skrll  * memory mapped file as the bus.
     60  1.4.2.2  skrll  */
     61  1.4.2.2  skrll 
     62  1.4.2.2  skrll static int	shmif_init(struct ifnet *);
     63  1.4.2.2  skrll static int	shmif_ioctl(struct ifnet *, u_long, void *);
     64  1.4.2.2  skrll static void	shmif_start(struct ifnet *);
     65  1.4.2.2  skrll static void	shmif_stop(struct ifnet *, int);
     66  1.4.2.2  skrll 
     67  1.4.2.2  skrll struct shmif_sc {
     68  1.4.2.2  skrll 	struct ethercom sc_ec;
     69  1.4.2.2  skrll 	uint8_t sc_myaddr[6];
     70  1.4.2.2  skrll 	uint8_t *sc_busmem;
     71  1.4.2.2  skrll 	int sc_memfd;
     72  1.4.2.2  skrll 	int sc_kq;
     73  1.4.2.2  skrll 
     74  1.4.2.2  skrll 	uint32_t sc_nextpacket;
     75  1.4.2.2  skrll 	uint32_t sc_prevgen;
     76  1.4.2.2  skrll };
     77  1.4.2.2  skrll #define IFMEM_LOCK		(0)
     78  1.4.2.2  skrll #define IFMEM_GENERATION	(8)
     79  1.4.2.2  skrll #define IFMEM_LASTPACKET	(12)
     80  1.4.2.2  skrll #define IFMEM_WAKEUP		(16)
     81  1.4.2.2  skrll #define IFMEM_DATA		(20)
     82  1.4.2.2  skrll 
     83  1.4.2.2  skrll #define BUSCTRL_ATOFF(sc, off)	((uint32_t *)(sc->sc_busmem+(off)))
     84  1.4.2.2  skrll 
     85  1.4.2.2  skrll #define BUSMEM_SIZE 65536 /* enough? */
     86  1.4.2.2  skrll 
     87  1.4.2.2  skrll static void shmif_rcv(void *);
     88  1.4.2.2  skrll 
     89  1.4.2.2  skrll static uint32_t numif;
     90  1.4.2.2  skrll 
     91  1.4.2.2  skrll /*
     92  1.4.2.2  skrll  * This locking needs work and will misbehave severely if:
     93  1.4.2.2  skrll  * 1) the backing memory has to be paged in
     94  1.4.2.2  skrll  * 2) some lockholder exits while holding the lock
     95  1.4.2.2  skrll  */
     96  1.4.2.2  skrll static void
     97  1.4.2.2  skrll lockbus(struct shmif_sc *sc)
     98  1.4.2.2  skrll {
     99  1.4.2.2  skrll 
    100  1.4.2.2  skrll 	__cpu_simple_lock((__cpu_simple_lock_t *)sc->sc_busmem);
    101  1.4.2.2  skrll }
    102  1.4.2.2  skrll 
    103  1.4.2.2  skrll static void
    104  1.4.2.2  skrll unlockbus(struct shmif_sc *sc)
    105  1.4.2.2  skrll {
    106  1.4.2.2  skrll 
    107  1.4.2.2  skrll 	__cpu_simple_unlock((__cpu_simple_lock_t *)sc->sc_busmem);
    108  1.4.2.2  skrll }
    109  1.4.2.2  skrll 
    110  1.4.2.2  skrll static uint32_t
    111  1.4.2.2  skrll busread(struct shmif_sc *sc, void *dest, uint32_t off, size_t len)
    112  1.4.2.2  skrll {
    113  1.4.2.2  skrll 	size_t chunk;
    114  1.4.2.2  skrll 
    115  1.4.2.2  skrll 	KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE);
    116  1.4.2.2  skrll 	chunk = MIN(len, BUSMEM_SIZE - off);
    117  1.4.2.2  skrll 	memcpy(dest, sc->sc_busmem + off, chunk);
    118  1.4.2.2  skrll 	len -= chunk;
    119  1.4.2.2  skrll 
    120  1.4.2.2  skrll 	if (len == 0)
    121  1.4.2.2  skrll 		return off + chunk;
    122  1.4.2.2  skrll 
    123  1.4.2.2  skrll 	/* else, wraps around */
    124  1.4.2.2  skrll 	off = IFMEM_DATA;
    125  1.4.2.2  skrll 	sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
    126  1.4.2.2  skrll 
    127  1.4.2.2  skrll 	/* finish reading */
    128  1.4.2.2  skrll 	memcpy((uint8_t *)dest + chunk, sc->sc_busmem + off, len);
    129  1.4.2.2  skrll 	return off + len;
    130  1.4.2.2  skrll }
    131  1.4.2.2  skrll 
    132  1.4.2.2  skrll static uint32_t
    133  1.4.2.2  skrll buswrite(struct shmif_sc *sc, uint32_t off, void *data, size_t len)
    134  1.4.2.2  skrll {
    135  1.4.2.2  skrll 	size_t chunk;
    136  1.4.2.2  skrll 
    137  1.4.2.2  skrll 	KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE);
    138  1.4.2.2  skrll 
    139  1.4.2.2  skrll 	chunk = MIN(len, BUSMEM_SIZE - off);
    140  1.4.2.2  skrll 	memcpy(sc->sc_busmem + off, data, chunk);
    141  1.4.2.2  skrll 	len -= chunk;
    142  1.4.2.2  skrll 
    143  1.4.2.2  skrll 	if (len == 0)
    144  1.4.2.2  skrll 		return off + chunk;
    145  1.4.2.2  skrll 
    146  1.4.2.2  skrll 	DPRINTF(("buswrite wrap: wrote %d bytes to %d, left %d to %d",
    147  1.4.2.2  skrll 	    chunk, off, len, IFMEM_DATA));
    148  1.4.2.2  skrll 
    149  1.4.2.2  skrll 	/* else, wraps around */
    150  1.4.2.2  skrll 	off = IFMEM_DATA;
    151  1.4.2.2  skrll 	(*BUSCTRL_ATOFF(sc, IFMEM_GENERATION))++;
    152  1.4.2.2  skrll 	sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
    153  1.4.2.2  skrll 
    154  1.4.2.2  skrll 	/* finish writing */
    155  1.4.2.2  skrll 	memcpy(sc->sc_busmem + off, (uint8_t *)data + chunk, len);
    156  1.4.2.2  skrll 	return off + len;
    157  1.4.2.2  skrll }
    158  1.4.2.2  skrll 
    159  1.4.2.2  skrll static inline uint32_t
    160  1.4.2.2  skrll advance(uint32_t oldoff, uint32_t delta)
    161  1.4.2.2  skrll {
    162  1.4.2.2  skrll 	uint32_t newoff;
    163  1.4.2.2  skrll 
    164  1.4.2.2  skrll 	newoff = oldoff + delta;
    165  1.4.2.2  skrll 	if (newoff >= BUSMEM_SIZE)
    166  1.4.2.2  skrll 		newoff -= (BUSMEM_SIZE - IFMEM_DATA);
    167  1.4.2.2  skrll 	return newoff;
    168  1.4.2.2  skrll 
    169  1.4.2.2  skrll }
    170  1.4.2.2  skrll 
    171  1.4.2.2  skrll static uint32_t
    172  1.4.2.2  skrll nextpktoff(struct shmif_sc *sc, uint32_t oldoff)
    173  1.4.2.2  skrll {
    174  1.4.2.2  skrll 	uint32_t oldlen;
    175  1.4.2.2  skrll 
    176  1.4.2.2  skrll 	busread(sc, &oldlen, oldoff, 4);
    177  1.4.2.2  skrll 	KASSERT(oldlen < BUSMEM_SIZE - IFMEM_DATA);
    178  1.4.2.2  skrll 
    179  1.4.2.2  skrll 	return advance(oldoff, 4 + oldlen);
    180  1.4.2.2  skrll }
    181  1.4.2.2  skrll 
    182  1.4.2.2  skrll int rump_shmif_create(const char *, int *); /* XXX */
    183  1.4.2.2  skrll 
    184  1.4.2.2  skrll int
    185  1.4.2.2  skrll rump_shmif_create(const char *path, int *ifnum)
    186  1.4.2.2  skrll {
    187  1.4.2.2  skrll 	struct shmif_sc *sc;
    188  1.4.2.2  skrll 	struct ifnet *ifp;
    189  1.4.2.2  skrll 	uint8_t enaddr[ETHER_ADDR_LEN] = { 0xb2, 0xa0, 0x00, 0x00, 0x00, 0x00 };
    190  1.4.2.2  skrll 	uint32_t randnum;
    191  1.4.2.2  skrll 	unsigned mynum;
    192  1.4.2.2  skrll 	int error;
    193  1.4.2.2  skrll 
    194  1.4.2.2  skrll 	randnum = arc4random();
    195  1.4.2.2  skrll 	memcpy(&enaddr[2], &randnum, 4);
    196  1.4.2.2  skrll 	mynum = atomic_inc_uint_nv(&numif)-1;
    197  1.4.2.2  skrll 
    198  1.4.2.2  skrll 	sc = kmem_zalloc(sizeof(*sc), KM_SLEEP);
    199  1.4.2.2  skrll 	ifp = &sc->sc_ec.ec_if;
    200  1.4.2.2  skrll 	memcpy(sc->sc_myaddr, enaddr, sizeof(enaddr));
    201  1.4.2.2  skrll 
    202  1.4.2.2  skrll 	sc->sc_memfd = rumpuser_open(path, O_RDWR | O_CREAT, &error);
    203  1.4.2.2  skrll 	if (sc->sc_memfd == -1)
    204  1.4.2.2  skrll 		goto fail;
    205  1.4.2.2  skrll 	sc->sc_busmem = rumpuser_filemmap(sc->sc_memfd, 0, BUSMEM_SIZE,
    206  1.4.2.3  skrll 	    RUMPUSER_FILEMMAP_TRUNCATE | RUMPUSER_FILEMMAP_SHARED
    207  1.4.2.3  skrll 	    | RUMPUSER_FILEMMAP_READ | RUMPUSER_FILEMMAP_WRITE, &error);
    208  1.4.2.2  skrll 	if (error)
    209  1.4.2.2  skrll 		goto fail;
    210  1.4.2.2  skrll 
    211  1.4.2.2  skrll 	lockbus(sc);
    212  1.4.2.2  skrll 	if (*BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) == 0)
    213  1.4.2.2  skrll 		*BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = IFMEM_DATA;
    214  1.4.2.2  skrll 	sc->sc_nextpacket = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET);
    215  1.4.2.2  skrll 	sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
    216  1.4.2.2  skrll 	unlockbus(sc);
    217  1.4.2.2  skrll 
    218  1.4.2.2  skrll 	sc->sc_kq = rumpuser_writewatchfile_setup(-1, sc->sc_memfd, 0, &error);
    219  1.4.2.2  skrll 	if (sc->sc_kq == -1)
    220  1.4.2.2  skrll 		goto fail;
    221  1.4.2.2  skrll 
    222  1.4.2.2  skrll 	sprintf(ifp->if_xname, "shmif%d", mynum);
    223  1.4.2.2  skrll 	ifp->if_softc = sc;
    224  1.4.2.2  skrll 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
    225  1.4.2.2  skrll 	ifp->if_init = shmif_init;
    226  1.4.2.2  skrll 	ifp->if_ioctl = shmif_ioctl;
    227  1.4.2.2  skrll 	ifp->if_start = shmif_start;
    228  1.4.2.2  skrll 	ifp->if_stop = shmif_stop;
    229  1.4.2.2  skrll 	ifp->if_mtu = 1518;
    230  1.4.2.2  skrll 
    231  1.4.2.2  skrll 	if_attach(ifp);
    232  1.4.2.2  skrll 	ether_ifattach(ifp, enaddr);
    233  1.4.2.2  skrll 
    234  1.4.2.2  skrll 	if (ifnum)
    235  1.4.2.2  skrll 		*ifnum = mynum;
    236  1.4.2.2  skrll 	return 0;
    237  1.4.2.2  skrll 
    238  1.4.2.2  skrll  fail:
    239  1.4.2.2  skrll 	panic("rump_shmemif_create: fixme");
    240  1.4.2.2  skrll }
    241  1.4.2.2  skrll 
    242  1.4.2.2  skrll static int
    243  1.4.2.2  skrll shmif_init(struct ifnet *ifp)
    244  1.4.2.2  skrll {
    245  1.4.2.2  skrll 	int error = 0;
    246  1.4.2.2  skrll 
    247  1.4.2.2  skrll 	if (rump_threads) {
    248  1.4.2.2  skrll 		error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL,
    249  1.4.2.2  skrll 		    shmif_rcv, ifp, NULL, "shmif");
    250  1.4.2.2  skrll 	} else {
    251  1.4.2.2  skrll 		printf("WARNING: threads not enabled, shmif NOT working\n");
    252  1.4.2.2  skrll 	}
    253  1.4.2.2  skrll 
    254  1.4.2.2  skrll 	ifp->if_flags |= IFF_RUNNING;
    255  1.4.2.2  skrll 	return error;
    256  1.4.2.2  skrll }
    257  1.4.2.2  skrll 
    258  1.4.2.2  skrll static int
    259  1.4.2.2  skrll shmif_ioctl(struct ifnet *ifp, u_long cmd, void *data)
    260  1.4.2.2  skrll {
    261  1.4.2.2  skrll 	int s, rv;
    262  1.4.2.2  skrll 
    263  1.4.2.2  skrll 	s = splnet();
    264  1.4.2.2  skrll 	rv = ether_ioctl(ifp, cmd, data);
    265  1.4.2.2  skrll 	splx(s);
    266  1.4.2.2  skrll 
    267  1.4.2.2  skrll 	return rv;
    268  1.4.2.2  skrll }
    269  1.4.2.2  skrll 
    270  1.4.2.2  skrll /* send everything in-context */
    271  1.4.2.2  skrll static void
    272  1.4.2.2  skrll shmif_start(struct ifnet *ifp)
    273  1.4.2.2  skrll {
    274  1.4.2.2  skrll 	struct shmif_sc *sc = ifp->if_softc;
    275  1.4.2.2  skrll 	struct mbuf *m, *m0;
    276  1.4.2.2  skrll 	uint32_t lastoff, dataoff, npktlenoff;
    277  1.4.2.2  skrll 	uint32_t pktsize = 0;
    278  1.4.2.2  skrll 	bool wrote = false;
    279  1.4.2.2  skrll 	int error;
    280  1.4.2.2  skrll 
    281  1.4.2.2  skrll 	for (;;) {
    282  1.4.2.2  skrll 		IF_DEQUEUE(&ifp->if_snd, m0);
    283  1.4.2.2  skrll 		if (m0 == NULL) {
    284  1.4.2.2  skrll 			break;
    285  1.4.2.2  skrll 		}
    286  1.4.2.2  skrll 
    287  1.4.2.2  skrll 		lockbus(sc);
    288  1.4.2.2  skrll 		lastoff = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET);
    289  1.4.2.2  skrll 
    290  1.4.2.2  skrll 		npktlenoff = nextpktoff(sc, lastoff);
    291  1.4.2.2  skrll 		dataoff = advance(npktlenoff, 4);
    292  1.4.2.2  skrll 
    293  1.4.2.2  skrll 		for (m = m0; m != NULL; m = m->m_next) {
    294  1.4.2.2  skrll 			pktsize += m->m_len;
    295  1.4.2.2  skrll 			dataoff = buswrite(sc, dataoff, mtod(m, void *),
    296  1.4.2.2  skrll 			    m->m_len);
    297  1.4.2.2  skrll 		}
    298  1.4.2.2  skrll 		buswrite(sc, npktlenoff, &pktsize, 4);
    299  1.4.2.2  skrll 		*BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = npktlenoff;
    300  1.4.2.2  skrll 		unlockbus(sc);
    301  1.4.2.2  skrll 
    302  1.4.2.2  skrll 		m_freem(m0);
    303  1.4.2.2  skrll 		wrote = true;
    304  1.4.2.2  skrll 
    305  1.4.2.2  skrll 		DPRINTF(("shmif_start: send %d bytes at off %d\n",
    306  1.4.2.2  skrll 		    pktsize, npktlenoff));
    307  1.4.2.2  skrll 	}
    308  1.4.2.2  skrll 	/* wakeup */
    309  1.4.2.2  skrll 	if (wrote)
    310  1.4.2.2  skrll 		rumpuser_pwrite(sc->sc_memfd, &error, 4, IFMEM_WAKEUP, &error);
    311  1.4.2.2  skrll }
    312  1.4.2.2  skrll 
    313  1.4.2.2  skrll static void
    314  1.4.2.2  skrll shmif_stop(struct ifnet *ifp, int disable)
    315  1.4.2.2  skrll {
    316  1.4.2.2  skrll 
    317  1.4.2.2  skrll 	panic("%s: unimpl", __func__);
    318  1.4.2.2  skrll }
    319  1.4.2.2  skrll 
    320  1.4.2.2  skrll static void
    321  1.4.2.2  skrll shmif_rcv(void *arg)
    322  1.4.2.2  skrll {
    323  1.4.2.2  skrll 	struct ifnet *ifp = arg;
    324  1.4.2.2  skrll 	struct shmif_sc *sc = ifp->if_softc;
    325  1.4.2.2  skrll 	struct mbuf *m = NULL;
    326  1.4.2.2  skrll 	struct ether_header *eth;
    327  1.4.2.2  skrll 	uint32_t nextpkt, pktlen, lastpkt, busgen, lastnext;
    328  1.4.2.2  skrll 	int error;
    329  1.4.2.2  skrll 
    330  1.4.2.2  skrll 	for (;;) {
    331  1.4.2.2  skrll 		if (m == NULL) {
    332  1.4.2.2  skrll 			m = m_gethdr(M_WAIT, MT_DATA);
    333  1.4.2.2  skrll 			MCLGET(m, M_WAIT);
    334  1.4.2.2  skrll 		}
    335  1.4.2.2  skrll 
    336  1.4.2.2  skrll 		DPRINTF(("waiting %d/%d\n", sc->sc_nextpacket, sc->sc_prevgen));
    337  1.4.2.2  skrll 
    338  1.4.2.2  skrll 		KASSERT(m->m_flags & M_EXT);
    339  1.4.2.2  skrll 		lockbus(sc);
    340  1.4.2.2  skrll 		lastpkt = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET);
    341  1.4.2.2  skrll 		busgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
    342  1.4.2.2  skrll 		lastnext = nextpktoff(sc, lastpkt);
    343  1.4.2.2  skrll 		if ((lastnext > sc->sc_nextpacket && busgen > sc->sc_prevgen)
    344  1.4.2.2  skrll 		    || (busgen > sc->sc_prevgen+1)) {
    345  1.4.2.2  skrll 			nextpkt = lastpkt;
    346  1.4.2.2  skrll 			sc->sc_prevgen = busgen;
    347  1.4.2.2  skrll 			printf("DROPPING\n");
    348  1.4.2.2  skrll 		} else {
    349  1.4.2.2  skrll 			nextpkt = sc->sc_nextpacket;
    350  1.4.2.2  skrll 		}
    351  1.4.2.2  skrll 
    352  1.4.2.2  skrll 		/* need more data? */
    353  1.4.2.2  skrll 		if (lastnext == nextpkt && sc->sc_prevgen == busgen){
    354  1.4.2.2  skrll 			unlockbus(sc);
    355  1.4.2.2  skrll 			error = 0;
    356  1.4.2.2  skrll 			rumpuser_writewatchfile_wait(sc->sc_kq, NULL, &error);
    357  1.4.2.2  skrll 			if (__predict_false(error))
    358  1.4.2.2  skrll 				printf("shmif_rcv: wait failed %d\n", error);
    359  1.4.2.2  skrll 			continue;
    360  1.4.2.2  skrll 		}
    361  1.4.2.2  skrll 
    362  1.4.2.2  skrll 		busread(sc, &pktlen, nextpkt, 4);
    363  1.4.2.2  skrll 		busread(sc, mtod(m, void *), advance(nextpkt, 4), pktlen);
    364  1.4.2.2  skrll 
    365  1.4.2.2  skrll 		DPRINTF(("shmif_rcv: read packet of length %d at %d\n",
    366  1.4.2.2  skrll 		    pktlen, nextpkt));
    367  1.4.2.2  skrll 
    368  1.4.2.2  skrll 		sc->sc_nextpacket = nextpktoff(sc, nextpkt);
    369  1.4.2.2  skrll 		sc->sc_prevgen = busgen;
    370  1.4.2.2  skrll 		unlockbus(sc);
    371  1.4.2.2  skrll 
    372  1.4.2.2  skrll 		m->m_len = m->m_pkthdr.len = pktlen;
    373  1.4.2.2  skrll 		m->m_pkthdr.rcvif = ifp;
    374  1.4.2.2  skrll 
    375  1.4.2.2  skrll 		/* if it's to us, don't pass up and reuse storage space */
    376  1.4.2.2  skrll 		eth = mtod(m, struct ether_header *);
    377  1.4.2.2  skrll 		if (memcmp(eth->ether_shost, sc->sc_myaddr, 6) != 0) {
    378  1.4.2.2  skrll 			ifp->if_input(ifp, m);
    379  1.4.2.2  skrll 			m = NULL;
    380  1.4.2.2  skrll 		}
    381  1.4.2.2  skrll 	}
    382  1.4.2.2  skrll 
    383  1.4.2.2  skrll 	panic("shmif_worker is a lazy boy %d\n", error);
    384  1.4.2.2  skrll }
    385