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if_shmem.c revision 1.13
      1  1.13   pooka /*	$NetBSD: if_shmem.c,v 1.13 2010/08/10 18:17:12 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  1.13   pooka __KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.13 2010/08/10 18:17:12 pooka Exp $");
     32   1.1   pooka 
     33   1.1   pooka #include <sys/param.h>
     34  1.13   pooka #include <sys/atomic.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   1.3  martin #include <sys/atomic.h>
     40   1.1   pooka 
     41   1.1   pooka #include <net/if.h>
     42   1.1   pooka #include <net/if_ether.h>
     43   1.1   pooka 
     44   1.1   pooka #include <netinet/in.h>
     45   1.1   pooka #include <netinet/in_var.h>
     46   1.1   pooka 
     47   1.1   pooka #include <rump/rump.h>
     48   1.1   pooka #include <rump/rumpuser.h>
     49   1.1   pooka 
     50   1.1   pooka #include "rump_private.h"
     51   1.9   pooka #include "rump_net_private.h"
     52   1.1   pooka 
     53   1.6   pooka #if 0
     54   1.8   pooka #define DPRINTF(x) rumpuser_dprintf x
     55   1.6   pooka #else
     56   1.6   pooka #define DPRINTF(x)
     57   1.6   pooka #endif
     58   1.6   pooka 
     59   1.1   pooka /*
     60   1.1   pooka  * A virtual ethernet interface which uses shared memory from a
     61   1.1   pooka  * memory mapped file as the bus.
     62   1.1   pooka  */
     63   1.1   pooka 
     64   1.1   pooka static int	shmif_init(struct ifnet *);
     65   1.1   pooka static int	shmif_ioctl(struct ifnet *, u_long, void *);
     66   1.1   pooka static void	shmif_start(struct ifnet *);
     67   1.1   pooka static void	shmif_stop(struct ifnet *, int);
     68   1.1   pooka 
     69   1.1   pooka struct shmif_sc {
     70   1.1   pooka 	struct ethercom sc_ec;
     71   1.1   pooka 	uint8_t sc_myaddr[6];
     72   1.1   pooka 	uint8_t *sc_busmem;
     73   1.1   pooka 	int sc_memfd;
     74   1.1   pooka 	int sc_kq;
     75   1.1   pooka 
     76   1.1   pooka 	uint32_t sc_nextpacket;
     77   1.1   pooka 	uint32_t sc_prevgen;
     78   1.1   pooka };
     79   1.1   pooka #define IFMEM_LOCK		(0)
     80   1.1   pooka #define IFMEM_GENERATION	(8)
     81   1.1   pooka #define IFMEM_LASTPACKET	(12)
     82   1.1   pooka #define IFMEM_WAKEUP		(16)
     83   1.1   pooka #define IFMEM_DATA		(20)
     84   1.1   pooka 
     85   1.1   pooka #define BUSCTRL_ATOFF(sc, off)	((uint32_t *)(sc->sc_busmem+(off)))
     86   1.1   pooka 
     87  1.11   pooka #define BUSMEM_SIZE (1024*1024) /* need write throttling? */
     88   1.1   pooka 
     89   1.1   pooka static void shmif_rcv(void *);
     90   1.1   pooka 
     91   1.1   pooka static uint32_t numif;
     92   1.1   pooka 
     93  1.13   pooka #define LOCK_UNLOCKED	0
     94  1.13   pooka #define LOCK_LOCKED	1
     95  1.13   pooka 
     96   1.2   pooka /*
     97   1.2   pooka  * This locking needs work and will misbehave severely if:
     98   1.2   pooka  * 1) the backing memory has to be paged in
     99   1.2   pooka  * 2) some lockholder exits while holding the lock
    100   1.2   pooka  */
    101   1.1   pooka static void
    102   1.1   pooka lockbus(struct shmif_sc *sc)
    103   1.1   pooka {
    104   1.1   pooka 
    105  1.13   pooka 	while (atomic_cas_uint((void *)sc->sc_busmem,
    106  1.13   pooka 	    LOCK_UNLOCKED, LOCK_LOCKED) == LOCK_LOCKED)
    107  1.13   pooka 		continue;
    108  1.13   pooka 	membar_enter();
    109   1.1   pooka }
    110   1.1   pooka 
    111   1.1   pooka static void
    112   1.1   pooka unlockbus(struct shmif_sc *sc)
    113   1.1   pooka {
    114  1.13   pooka 	unsigned int old;
    115   1.1   pooka 
    116  1.13   pooka 	membar_exit();
    117  1.13   pooka 	old = atomic_swap_uint((void *)sc->sc_busmem, LOCK_UNLOCKED);
    118  1.13   pooka 	KASSERT(old == LOCK_LOCKED);
    119   1.1   pooka }
    120   1.1   pooka 
    121   1.1   pooka static uint32_t
    122   1.1   pooka busread(struct shmif_sc *sc, void *dest, uint32_t off, size_t len)
    123   1.1   pooka {
    124   1.1   pooka 	size_t chunk;
    125   1.1   pooka 
    126   1.1   pooka 	KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE);
    127   1.1   pooka 	chunk = MIN(len, BUSMEM_SIZE - off);
    128   1.1   pooka 	memcpy(dest, sc->sc_busmem + off, chunk);
    129   1.1   pooka 	len -= chunk;
    130   1.1   pooka 
    131   1.1   pooka 	if (len == 0)
    132   1.1   pooka 		return off + chunk;
    133   1.1   pooka 
    134   1.1   pooka 	/* else, wraps around */
    135   1.1   pooka 	off = IFMEM_DATA;
    136   1.1   pooka 	sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
    137   1.1   pooka 
    138   1.1   pooka 	/* finish reading */
    139   1.1   pooka 	memcpy((uint8_t *)dest + chunk, sc->sc_busmem + off, len);
    140   1.1   pooka 	return off + len;
    141   1.1   pooka }
    142   1.1   pooka 
    143   1.1   pooka static uint32_t
    144   1.1   pooka buswrite(struct shmif_sc *sc, uint32_t off, void *data, size_t len)
    145   1.1   pooka {
    146   1.1   pooka 	size_t chunk;
    147   1.1   pooka 
    148  1.12   pooka 	KASSERT(len < (BUSMEM_SIZE - IFMEM_DATA) && off <= BUSMEM_SIZE
    149  1.12   pooka 	    && off >= IFMEM_DATA);
    150   1.1   pooka 
    151   1.1   pooka 	chunk = MIN(len, BUSMEM_SIZE - off);
    152   1.1   pooka 	memcpy(sc->sc_busmem + off, data, chunk);
    153   1.1   pooka 	len -= chunk;
    154   1.1   pooka 
    155   1.1   pooka 	if (len == 0)
    156   1.1   pooka 		return off + chunk;
    157   1.1   pooka 
    158   1.1   pooka 	DPRINTF(("buswrite wrap: wrote %d bytes to %d, left %d to %d",
    159   1.1   pooka 	    chunk, off, len, IFMEM_DATA));
    160   1.1   pooka 
    161   1.1   pooka 	/* else, wraps around */
    162   1.1   pooka 	off = IFMEM_DATA;
    163   1.1   pooka 	(*BUSCTRL_ATOFF(sc, IFMEM_GENERATION))++;
    164   1.1   pooka 	sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
    165   1.1   pooka 
    166   1.1   pooka 	/* finish writing */
    167   1.1   pooka 	memcpy(sc->sc_busmem + off, (uint8_t *)data + chunk, len);
    168   1.1   pooka 	return off + len;
    169   1.1   pooka }
    170   1.1   pooka 
    171   1.1   pooka static inline uint32_t
    172   1.1   pooka advance(uint32_t oldoff, uint32_t delta)
    173   1.1   pooka {
    174   1.1   pooka 	uint32_t newoff;
    175   1.1   pooka 
    176   1.1   pooka 	newoff = oldoff + delta;
    177   1.1   pooka 	if (newoff >= BUSMEM_SIZE)
    178   1.1   pooka 		newoff -= (BUSMEM_SIZE - IFMEM_DATA);
    179   1.1   pooka 	return newoff;
    180   1.1   pooka 
    181   1.1   pooka }
    182   1.1   pooka 
    183   1.1   pooka static uint32_t
    184   1.1   pooka nextpktoff(struct shmif_sc *sc, uint32_t oldoff)
    185   1.1   pooka {
    186   1.1   pooka 	uint32_t oldlen;
    187   1.1   pooka 
    188   1.1   pooka 	busread(sc, &oldlen, oldoff, 4);
    189   1.1   pooka 	KASSERT(oldlen < BUSMEM_SIZE - IFMEM_DATA);
    190   1.1   pooka 
    191   1.1   pooka 	return advance(oldoff, 4 + oldlen);
    192   1.1   pooka }
    193   1.1   pooka 
    194   1.1   pooka int
    195   1.1   pooka rump_shmif_create(const char *path, int *ifnum)
    196   1.1   pooka {
    197   1.1   pooka 	struct shmif_sc *sc;
    198   1.1   pooka 	struct ifnet *ifp;
    199   1.1   pooka 	uint8_t enaddr[ETHER_ADDR_LEN] = { 0xb2, 0xa0, 0x00, 0x00, 0x00, 0x00 };
    200   1.1   pooka 	uint32_t randnum;
    201   1.1   pooka 	unsigned mynum;
    202   1.1   pooka 	int error;
    203   1.1   pooka 
    204   1.1   pooka 	randnum = arc4random();
    205   1.1   pooka 	memcpy(&enaddr[2], &randnum, 4);
    206   1.1   pooka 	mynum = atomic_inc_uint_nv(&numif)-1;
    207   1.1   pooka 
    208   1.1   pooka 	sc = kmem_zalloc(sizeof(*sc), KM_SLEEP);
    209   1.1   pooka 	ifp = &sc->sc_ec.ec_if;
    210   1.1   pooka 	memcpy(sc->sc_myaddr, enaddr, sizeof(enaddr));
    211   1.1   pooka 
    212   1.1   pooka 	sc->sc_memfd = rumpuser_open(path, O_RDWR | O_CREAT, &error);
    213   1.1   pooka 	if (sc->sc_memfd == -1)
    214   1.1   pooka 		goto fail;
    215   1.1   pooka 	sc->sc_busmem = rumpuser_filemmap(sc->sc_memfd, 0, BUSMEM_SIZE,
    216   1.5   pooka 	    RUMPUSER_FILEMMAP_TRUNCATE | RUMPUSER_FILEMMAP_SHARED
    217   1.5   pooka 	    | RUMPUSER_FILEMMAP_READ | RUMPUSER_FILEMMAP_WRITE, &error);
    218   1.1   pooka 	if (error)
    219   1.1   pooka 		goto fail;
    220   1.1   pooka 
    221   1.1   pooka 	lockbus(sc);
    222   1.1   pooka 	if (*BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) == 0)
    223   1.1   pooka 		*BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = IFMEM_DATA;
    224   1.1   pooka 	sc->sc_nextpacket = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET);
    225   1.1   pooka 	sc->sc_prevgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
    226   1.1   pooka 	unlockbus(sc);
    227   1.1   pooka 
    228   1.1   pooka 	sc->sc_kq = rumpuser_writewatchfile_setup(-1, sc->sc_memfd, 0, &error);
    229   1.1   pooka 	if (sc->sc_kq == -1)
    230   1.1   pooka 		goto fail;
    231   1.1   pooka 
    232   1.1   pooka 	sprintf(ifp->if_xname, "shmif%d", mynum);
    233   1.1   pooka 	ifp->if_softc = sc;
    234  1.13   pooka 	ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST;
    235   1.1   pooka 	ifp->if_init = shmif_init;
    236   1.1   pooka 	ifp->if_ioctl = shmif_ioctl;
    237   1.1   pooka 	ifp->if_start = shmif_start;
    238   1.1   pooka 	ifp->if_stop = shmif_stop;
    239   1.1   pooka 	ifp->if_mtu = 1518;
    240   1.1   pooka 
    241   1.1   pooka 	if_attach(ifp);
    242   1.1   pooka 	ether_ifattach(ifp, enaddr);
    243   1.1   pooka 
    244  1.12   pooka 	aprint_verbose("shmif%d: bus %s\n", mynum, path);
    245  1.12   pooka 	aprint_verbose("shmif%d: Ethernet address %s\n",
    246  1.12   pooka 	    mynum, ether_sprintf(enaddr));
    247  1.12   pooka 
    248   1.2   pooka 	if (ifnum)
    249   1.2   pooka 		*ifnum = mynum;
    250   1.1   pooka 	return 0;
    251   1.1   pooka 
    252   1.1   pooka  fail:
    253   1.1   pooka 	panic("rump_shmemif_create: fixme");
    254   1.1   pooka }
    255   1.1   pooka 
    256   1.1   pooka static int
    257   1.1   pooka shmif_init(struct ifnet *ifp)
    258   1.1   pooka {
    259   1.4   pooka 	int error = 0;
    260   1.4   pooka 
    261   1.4   pooka 	if (rump_threads) {
    262   1.4   pooka 		error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL,
    263   1.4   pooka 		    shmif_rcv, ifp, NULL, "shmif");
    264   1.4   pooka 	} else {
    265   1.4   pooka 		printf("WARNING: threads not enabled, shmif NOT working\n");
    266   1.4   pooka 	}
    267   1.1   pooka 
    268   1.1   pooka 	ifp->if_flags |= IFF_RUNNING;
    269   1.4   pooka 	return error;
    270   1.1   pooka }
    271   1.1   pooka 
    272   1.1   pooka static int
    273   1.1   pooka shmif_ioctl(struct ifnet *ifp, u_long cmd, void *data)
    274   1.1   pooka {
    275   1.1   pooka 	int s, rv;
    276   1.1   pooka 
    277   1.1   pooka 	s = splnet();
    278   1.1   pooka 	rv = ether_ioctl(ifp, cmd, data);
    279   1.7   pooka 	if (rv == ENETRESET)
    280   1.7   pooka 		rv = 0;
    281   1.1   pooka 	splx(s);
    282   1.1   pooka 
    283   1.1   pooka 	return rv;
    284   1.1   pooka }
    285   1.1   pooka 
    286   1.1   pooka /* send everything in-context */
    287   1.1   pooka static void
    288   1.1   pooka shmif_start(struct ifnet *ifp)
    289   1.1   pooka {
    290   1.1   pooka 	struct shmif_sc *sc = ifp->if_softc;
    291   1.1   pooka 	struct mbuf *m, *m0;
    292   1.1   pooka 	uint32_t lastoff, dataoff, npktlenoff;
    293   1.1   pooka 	uint32_t pktsize = 0;
    294   1.1   pooka 	bool wrote = false;
    295   1.1   pooka 	int error;
    296   1.1   pooka 
    297   1.1   pooka 	for (;;) {
    298   1.1   pooka 		IF_DEQUEUE(&ifp->if_snd, m0);
    299   1.1   pooka 		if (m0 == NULL) {
    300   1.1   pooka 			break;
    301   1.1   pooka 		}
    302   1.1   pooka 
    303   1.1   pooka 		lockbus(sc);
    304   1.1   pooka 		lastoff = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET);
    305   1.1   pooka 
    306   1.1   pooka 		npktlenoff = nextpktoff(sc, lastoff);
    307   1.1   pooka 		dataoff = advance(npktlenoff, 4);
    308   1.1   pooka 
    309   1.1   pooka 		for (m = m0; m != NULL; m = m->m_next) {
    310   1.1   pooka 			pktsize += m->m_len;
    311   1.1   pooka 			dataoff = buswrite(sc, dataoff, mtod(m, void *),
    312   1.1   pooka 			    m->m_len);
    313   1.1   pooka 		}
    314   1.1   pooka 		buswrite(sc, npktlenoff, &pktsize, 4);
    315   1.1   pooka 		*BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET) = npktlenoff;
    316   1.1   pooka 		unlockbus(sc);
    317   1.1   pooka 
    318   1.1   pooka 		m_freem(m0);
    319   1.1   pooka 		wrote = true;
    320   1.1   pooka 
    321   1.1   pooka 		DPRINTF(("shmif_start: send %d bytes at off %d\n",
    322   1.1   pooka 		    pktsize, npktlenoff));
    323   1.1   pooka 	}
    324   1.1   pooka 	/* wakeup */
    325   1.1   pooka 	if (wrote)
    326   1.1   pooka 		rumpuser_pwrite(sc->sc_memfd, &error, 4, IFMEM_WAKEUP, &error);
    327   1.1   pooka }
    328   1.1   pooka 
    329   1.1   pooka static void
    330   1.1   pooka shmif_stop(struct ifnet *ifp, int disable)
    331   1.1   pooka {
    332   1.1   pooka 
    333   1.1   pooka 	panic("%s: unimpl", __func__);
    334   1.1   pooka }
    335   1.1   pooka 
    336   1.1   pooka static void
    337   1.1   pooka shmif_rcv(void *arg)
    338   1.1   pooka {
    339   1.1   pooka 	struct ifnet *ifp = arg;
    340   1.1   pooka 	struct shmif_sc *sc = ifp->if_softc;
    341   1.1   pooka 	struct mbuf *m = NULL;
    342   1.1   pooka 	struct ether_header *eth;
    343   1.1   pooka 	uint32_t nextpkt, pktlen, lastpkt, busgen, lastnext;
    344   1.1   pooka 	int error;
    345   1.1   pooka 
    346   1.1   pooka 	for (;;) {
    347   1.1   pooka 		if (m == NULL) {
    348   1.1   pooka 			m = m_gethdr(M_WAIT, MT_DATA);
    349   1.1   pooka 			MCLGET(m, M_WAIT);
    350   1.1   pooka 		}
    351   1.1   pooka 
    352   1.1   pooka 		DPRINTF(("waiting %d/%d\n", sc->sc_nextpacket, sc->sc_prevgen));
    353   1.1   pooka 
    354   1.1   pooka 		KASSERT(m->m_flags & M_EXT);
    355   1.1   pooka 		lockbus(sc);
    356   1.1   pooka 		lastpkt = *BUSCTRL_ATOFF(sc, IFMEM_LASTPACKET);
    357   1.1   pooka 		busgen = *BUSCTRL_ATOFF(sc, IFMEM_GENERATION);
    358   1.1   pooka 		lastnext = nextpktoff(sc, lastpkt);
    359   1.1   pooka 		if ((lastnext > sc->sc_nextpacket && busgen > sc->sc_prevgen)
    360   1.1   pooka 		    || (busgen > sc->sc_prevgen+1)) {
    361   1.1   pooka 			nextpkt = lastpkt;
    362   1.1   pooka 			sc->sc_prevgen = busgen;
    363  1.11   pooka 			rumpuser_dprintf("shmif_rcv: generation overrun, "
    364  1.11   pooka 			    "skipping invalid packets\n");
    365   1.1   pooka 		} else {
    366   1.1   pooka 			nextpkt = sc->sc_nextpacket;
    367   1.1   pooka 		}
    368   1.1   pooka 
    369   1.1   pooka 		/* need more data? */
    370   1.1   pooka 		if (lastnext == nextpkt && sc->sc_prevgen == busgen){
    371   1.1   pooka 			unlockbus(sc);
    372   1.1   pooka 			error = 0;
    373   1.1   pooka 			rumpuser_writewatchfile_wait(sc->sc_kq, NULL, &error);
    374   1.1   pooka 			if (__predict_false(error))
    375   1.1   pooka 				printf("shmif_rcv: wait failed %d\n", error);
    376   1.1   pooka 			continue;
    377   1.1   pooka 		}
    378   1.1   pooka 
    379   1.1   pooka 		busread(sc, &pktlen, nextpkt, 4);
    380   1.1   pooka 		busread(sc, mtod(m, void *), advance(nextpkt, 4), pktlen);
    381   1.1   pooka 
    382   1.1   pooka 		DPRINTF(("shmif_rcv: read packet of length %d at %d\n",
    383   1.1   pooka 		    pktlen, nextpkt));
    384   1.1   pooka 
    385   1.1   pooka 		sc->sc_nextpacket = nextpktoff(sc, nextpkt);
    386   1.1   pooka 		sc->sc_prevgen = busgen;
    387   1.1   pooka 		unlockbus(sc);
    388   1.1   pooka 
    389   1.1   pooka 		m->m_len = m->m_pkthdr.len = pktlen;
    390   1.1   pooka 		m->m_pkthdr.rcvif = ifp;
    391   1.1   pooka 
    392  1.10   pooka 		/* if it's from us, don't pass up and reuse storage space */
    393   1.1   pooka 		eth = mtod(m, struct ether_header *);
    394   1.1   pooka 		if (memcmp(eth->ether_shost, sc->sc_myaddr, 6) != 0) {
    395   1.1   pooka 			ifp->if_input(ifp, m);
    396   1.1   pooka 			m = NULL;
    397   1.1   pooka 		}
    398   1.1   pooka 	}
    399   1.1   pooka 
    400   1.1   pooka 	panic("shmif_worker is a lazy boy %d\n", error);
    401   1.1   pooka }
    402