Module Name: src
Committed By: pooka
Date: Thu Aug 12 21:41:47 UTC 2010
Modified Files:
src/sys/rump/net/lib/libshmif: Makefile dumpbus.c if_shmem.c shmifvar.h
Added Files:
src/sys/rump/net/lib/libshmif: shmif_busops.c
Log Message:
Include a pointer to the beginning of the buffer and add support
to the packet dumper. This helps in situations where the juicy
details are in a bus multiple generations old.
To generate a diff of this commit:
cvs rdiff -u -r1.1 -r1.2 src/sys/rump/net/lib/libshmif/Makefile
cvs rdiff -u -r1.5 -r1.6 src/sys/rump/net/lib/libshmif/dumpbus.c
cvs rdiff -u -r1.18 -r1.19 src/sys/rump/net/lib/libshmif/if_shmem.c
cvs rdiff -u -r0 -r1.1 src/sys/rump/net/lib/libshmif/shmif_busops.c
cvs rdiff -u -r1.2 -r1.3 src/sys/rump/net/lib/libshmif/shmifvar.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/rump/net/lib/libshmif/Makefile
diff -u src/sys/rump/net/lib/libshmif/Makefile:1.1 src/sys/rump/net/lib/libshmif/Makefile:1.2
--- src/sys/rump/net/lib/libshmif/Makefile:1.1 Sat Feb 28 15:28:46 2009
+++ src/sys/rump/net/lib/libshmif/Makefile Thu Aug 12 21:41:47 2010
@@ -1,9 +1,9 @@
-# $NetBSD: Makefile,v 1.1 2009/02/28 15:28:46 pooka Exp $
+# $NetBSD: Makefile,v 1.2 2010/08/12 21:41:47 pooka Exp $
#
LIB= rumpnet_shmif
-SRCS= if_shmem.c
+SRCS= if_shmem.c shmif_busops.c
CPPFLAGS+= -I${.CURDIR}/../../../librump/rumpkern
Index: src/sys/rump/net/lib/libshmif/dumpbus.c
diff -u src/sys/rump/net/lib/libshmif/dumpbus.c:1.5 src/sys/rump/net/lib/libshmif/dumpbus.c:1.6
--- src/sys/rump/net/lib/libshmif/dumpbus.c:1.5 Thu Aug 12 18:22:40 2010
+++ src/sys/rump/net/lib/libshmif/dumpbus.c Thu Aug 12 21:41:47 2010
@@ -1,4 +1,4 @@
-/* $NetBSD: dumpbus.c,v 1.5 2010/08/12 18:22:40 pooka Exp $ */
+/* $NetBSD: dumpbus.c,v 1.6 2010/08/12 21:41:47 pooka Exp $ */
/*
* Little utility to convert shmif bus traffic to a pcap file
@@ -13,12 +13,14 @@
#include <err.h>
#include <fcntl.h>
#include <pcap.h>
+#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "shmifvar.h"
+#include "shmif_busops.c"
static void
usage(void)
@@ -28,16 +30,19 @@
exit(1);
}
+#define BUFSIZE 64*1024
int
main(int argc, char *argv[])
{
struct stat sb;
void *busmem;
const char *pcapfile = NULL;
- uint8_t *curbus, *buslast;
+ uint32_t curbus, buslast;
struct shmif_mem *bmem;
int fd, pfd, i, ch;
uint32_t pktlen;
+ int bonus;
+ char *buf;
while ((ch = getopt(argc, argv, "p:")) != -1) {
switch (ch) {
@@ -55,6 +60,10 @@
if (argc != 1)
usage();
+ buf = malloc(BUFSIZE);
+ if (buf == NULL)
+ err(1, "malloc");
+
fd = open(argv[0], O_RDONLY);
if (fd == -1)
err(1, "open bus");
@@ -72,13 +81,10 @@
if (bmem->shm_version != SHMIF_VERSION)
errx(1, "bus vesrsion %d, program %d",
bmem->shm_version, SHMIF_VERSION);
- printf("bus version %d, lock: %d, generation: %d, lastoff: 0x%x\n",
- bmem->shm_version, bmem->shm_lock, bmem->shm_gen, bmem->shm_last);
-
- if (bmem->shm_gen != 0) {
- printf("this dumper can manage only generation 0, sorry\n");
- exit(0);
- }
+ printf("bus version %d, lock: %d, generation: %" PRIu64
+ ", firstoff: 0x%04x, lastoff: 0x%04x\n",
+ bmem->shm_version, bmem->shm_lock, bmem->shm_gen,
+ bmem->shm_first, bmem->shm_last);
if (pcapfile) {
struct pcap_file_header phdr;
@@ -102,25 +108,41 @@
err(1, "phdr write");
}
- curbus = bmem->shm_data;
- buslast = bmem->shm_data + bmem->shm_last;
+ curbus = bmem->shm_first;
+ buslast = bmem->shm_last;
+ if (curbus == BUSMEM_DATASIZE)
+ curbus = 0;
+
+ bonus = 0;
+ if (buslast < curbus)
+ bonus = 1;
+
assert(sizeof(pktlen) == PKTLEN_SIZE);
i = 0;
- while (curbus <= buslast) {
+ while (curbus <= buslast || bonus) {
struct pcap_pkthdr packhdr;
+ uint32_t oldoff;
+ bool wrap;
- pktlen = *(uint32_t *)curbus;
- curbus += sizeof(pktlen);
+ wrap = false;
+ oldoff = curbus;
+ curbus = shmif_busread(bmem,
+ &pktlen, oldoff, PKTLEN_SIZE, &wrap);
+ if (wrap)
+ bonus = 0;
if (pktlen == 0)
continue;
- printf("packet %d, offset 0x%x, length 0x%x\n",
- i++, curbus - bmem->shm_data, pktlen);
+ printf("packet %d, offset 0x%04x, length 0x%04x\n",
+ i++, curbus, pktlen);
if (!pcapfile || pktlen == 0) {
- curbus += pktlen;
+ curbus = shmif_busread(bmem,
+ buf, curbus, pktlen, &wrap);
+ if (wrap)
+ bonus = 0;
continue;
}
@@ -129,9 +151,11 @@
if (write(pfd, &packhdr, sizeof(packhdr)) != sizeof(packhdr))
err(1, "error writing packethdr");
- if (write(pfd, curbus, pktlen) != pktlen)
+ curbus = shmif_busread(bmem, buf, curbus, pktlen, &wrap);
+ if (write(pfd, buf, pktlen) != pktlen)
err(1, "write packet");
- curbus += pktlen;
+ if (wrap)
+ bonus = 0;
}
return 0;
Index: src/sys/rump/net/lib/libshmif/if_shmem.c
diff -u src/sys/rump/net/lib/libshmif/if_shmem.c:1.18 src/sys/rump/net/lib/libshmif/if_shmem.c:1.19
--- src/sys/rump/net/lib/libshmif/if_shmem.c:1.18 Thu Aug 12 18:39:54 2010
+++ src/sys/rump/net/lib/libshmif/if_shmem.c Thu Aug 12 21:41:47 2010
@@ -1,4 +1,4 @@
-/* $NetBSD: if_shmem.c,v 1.18 2010/08/12 18:39:54 pooka Exp $ */
+/* $NetBSD: if_shmem.c,v 1.19 2010/08/12 21:41:47 pooka Exp $ */
/*
* Copyright (c) 2009 Antti Kantee. All Rights Reserved.
@@ -28,7 +28,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.18 2010/08/12 18:39:54 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.19 2010/08/12 21:41:47 pooka Exp $");
#include <sys/param.h>
#include <sys/atomic.h>
@@ -50,12 +50,6 @@
#include "rump_private.h"
#include "rump_net_private.h"
-#if 0
-#define DPRINTF(x) rumpuser_dprintf x
-#else
-#define DPRINTF(x)
-#endif
-
/*
* A virtual ethernet interface which uses shared memory from a
* memory mapped file as the bus.
@@ -79,115 +73,12 @@
uint32_t sc_prevgen;
};
-#define BUSMEM_SIZE (1024*1024)
-#define BUSMEM_DATASIZE (BUSMEM_SIZE - sizeof(struct shmif_mem))
-
static const uint32_t busversion = SHMIF_VERSION;
static void shmif_rcv(void *);
static uint32_t numif;
-#define LOCK_UNLOCKED 0
-#define LOCK_LOCKED 1
-
-/*
- * This locking needs work and will misbehave severely if:
- * 1) the backing memory has to be paged in
- * 2) some lockholder exits while holding the lock
- */
-static void
-lockbus(struct shmif_sc *sc)
-{
-
- while (atomic_cas_32(&sc->sc_busmem->shm_lock,
- LOCK_UNLOCKED, LOCK_LOCKED) == LOCK_LOCKED)
- continue;
- membar_enter();
-}
-
-static void
-unlockbus(struct shmif_sc *sc)
-{
- unsigned int old;
-
- membar_exit();
- old = atomic_swap_32(&sc->sc_busmem->shm_lock, LOCK_UNLOCKED);
- KASSERT(old == LOCK_LOCKED);
-}
-
-static uint32_t
-busread(struct shmif_sc *sc, void *dest, uint32_t off, size_t len)
-{
- size_t chunk;
-
- KASSERT(len < (BUSMEM_DATASIZE) && off <= BUSMEM_DATASIZE);
- chunk = MIN(len, BUSMEM_DATASIZE - off);
- memcpy(dest, sc->sc_busmem->shm_data + off, chunk);
- len -= chunk;
-
- if (len == 0)
- return off + chunk;
-
- /* else, wraps around */
- off = 0;
- sc->sc_prevgen = sc->sc_busmem->shm_gen;
-
- /* finish reading */
- memcpy((uint8_t *)dest + chunk, sc->sc_busmem->shm_data + off, len);
- return off + len;
-}
-
-static uint32_t
-buswrite(struct shmif_sc *sc, uint32_t off, void *data, size_t len)
-{
- size_t chunk;
-
- KASSERT(len < (BUSMEM_DATASIZE) && off <= BUSMEM_DATASIZE);
-
- chunk = MIN(len, BUSMEM_DATASIZE - off);
- memcpy(sc->sc_busmem->shm_data + off, data, chunk);
- len -= chunk;
-
- if (len == 0)
- return off + chunk;
-
- DPRINTF(("buswrite wrap: wrote %d bytes to %d, left %d to 0",
- chunk, off, len));
-
- /* else, wraps around */
- off = 0;
- sc->sc_prevgen = sc->sc_busmem->shm_gen;
- sc->sc_busmem->shm_gen++;
-
- /* finish writing */
- memcpy(sc->sc_busmem->shm_data + off, (uint8_t *)data + chunk, len);
- return off + len;
-}
-
-static inline uint32_t
-advance(uint32_t oldoff, uint32_t delta)
-{
- uint32_t newoff;
-
- newoff = oldoff + delta;
- if (newoff >= BUSMEM_DATASIZE)
- newoff -= (BUSMEM_DATASIZE);
- return newoff;
-
-}
-
-static uint32_t
-nextpktoff(struct shmif_sc *sc, uint32_t oldoff)
-{
- uint32_t oldlen;
-
- busread(sc, &oldlen, oldoff, PKTLEN_SIZE);
- KASSERT(oldlen < BUSMEM_DATASIZE);
-
- return advance(oldoff, PKTLEN_SIZE + oldlen);
-}
-
int
rump_shmif_create(const char *path, int *ifnum)
{
@@ -217,12 +108,17 @@
if (sc->sc_busmem->shm_magic && sc->sc_busmem->shm_magic != SHMIF_MAGIC)
panic("bus is not magical");
- sc->sc_busmem->shm_magic = SHMIF_MAGIC;
- lockbus(sc);
+ shmif_lockbus(sc->sc_busmem);
+ /* we're first? initialize bus */
+ if (sc->sc_busmem->shm_magic == 0) {
+ sc->sc_busmem->shm_magic = SHMIF_MAGIC;
+ sc->sc_busmem->shm_first = BUSMEM_DATASIZE;
+ }
+
sc->sc_nextpacket = sc->sc_busmem->shm_last;
sc->sc_prevgen = sc->sc_busmem->shm_gen;
- unlockbus(sc);
+ shmif_unlockbus(sc->sc_busmem);
sc->sc_kq = rumpuser_writewatchfile_setup(-1, sc->sc_memfd, 0, &error);
if (sc->sc_kq == -1)
@@ -291,6 +187,7 @@
uint32_t lastoff, dataoff, npktlenoff;
uint32_t pktsize = 0;
bool wrote = false;
+ bool wrap = false;
int error;
for (;;) {
@@ -299,20 +196,25 @@
break;
}
- lockbus(sc);
- lastoff = sc->sc_busmem->shm_last;
+ for (m = m0; m != NULL; m = m->m_next) {
+ pktsize += m->m_len;
+ }
- npktlenoff = nextpktoff(sc, lastoff);
- dataoff = advance(npktlenoff, PKTLEN_SIZE);
+ shmif_lockbus(sc->sc_busmem);
+ lastoff = sc->sc_busmem->shm_last;
+ npktlenoff = shmif_nextpktoff(sc->sc_busmem, lastoff);
+ dataoff = shmif_buswrite(sc->sc_busmem,
+ npktlenoff, &pktsize, PKTLEN_SIZE, &wrap);
for (m = m0; m != NULL; m = m->m_next) {
- pktsize += m->m_len;
- dataoff = buswrite(sc, dataoff, mtod(m, void *),
- m->m_len);
+ dataoff = shmif_buswrite(sc->sc_busmem, dataoff,
+ mtod(m, void *), m->m_len, &wrap);
}
- buswrite(sc, npktlenoff, &pktsize, PKTLEN_SIZE);
+
+ if (wrap)
+ sc->sc_busmem->shm_gen++;
sc->sc_busmem->shm_last = npktlenoff;
- unlockbus(sc);
+ shmif_unlockbus(sc->sc_busmem);
m_freem(m0);
wrote = true;
@@ -341,6 +243,7 @@
struct mbuf *m = NULL;
struct ether_header *eth;
uint32_t nextpkt, pktlen, lastpkt, busgen, lastnext;
+ bool wrap = false;
int error;
for (;;) {
@@ -352,10 +255,10 @@
DPRINTF(("waiting %d/%d\n", sc->sc_nextpacket, sc->sc_prevgen));
KASSERT(m->m_flags & M_EXT);
- lockbus(sc);
+ shmif_lockbus(sc->sc_busmem);
lastpkt = sc->sc_busmem->shm_last;
busgen = sc->sc_busmem->shm_gen;
- lastnext = nextpktoff(sc, lastpkt);
+ lastnext = shmif_nextpktoff(sc->sc_busmem, lastpkt);
if ((lastnext > sc->sc_nextpacket && busgen > sc->sc_prevgen)
|| (busgen > sc->sc_prevgen+1)) {
nextpkt = lastpkt;
@@ -368,7 +271,7 @@
/* need more data? */
if (lastnext == nextpkt && sc->sc_prevgen == busgen){
- unlockbus(sc);
+ shmif_unlockbus(sc->sc_busmem);
error = 0;
rumpuser_writewatchfile_wait(sc->sc_kq, NULL, &error);
if (__predict_false(error))
@@ -376,16 +279,19 @@
continue;
}
- busread(sc, &pktlen, nextpkt, PKTLEN_SIZE);
- busread(sc, mtod(m, void *),
- advance(nextpkt, PKTLEN_SIZE), pktlen);
+ shmif_busread(sc->sc_busmem,
+ &pktlen, nextpkt, PKTLEN_SIZE, &wrap);
+ shmif_busread(sc->sc_busmem, mtod(m, void *),
+ shmif_advance(nextpkt, PKTLEN_SIZE), pktlen, &wrap);
+ if (wrap)
+ sc->sc_prevgen = sc->sc_busmem->shm_gen;
DPRINTF(("shmif_rcv: read packet of length %d at %d\n",
pktlen, nextpkt));
- sc->sc_nextpacket = nextpktoff(sc, nextpkt);
+ sc->sc_nextpacket = shmif_nextpktoff(sc->sc_busmem, nextpkt);
sc->sc_prevgen = busgen;
- unlockbus(sc);
+ shmif_unlockbus(sc->sc_busmem);
m->m_len = m->m_pkthdr.len = pktlen;
m->m_pkthdr.rcvif = ifp;
Index: src/sys/rump/net/lib/libshmif/shmifvar.h
diff -u src/sys/rump/net/lib/libshmif/shmifvar.h:1.2 src/sys/rump/net/lib/libshmif/shmifvar.h:1.3
--- src/sys/rump/net/lib/libshmif/shmifvar.h:1.2 Thu Aug 12 18:17:23 2010
+++ src/sys/rump/net/lib/libshmif/shmifvar.h Thu Aug 12 21:41:47 2010
@@ -1,4 +1,4 @@
-/* $NetBSD: shmifvar.h,v 1.2 2010/08/12 18:17:23 pooka Exp $ */
+/* $NetBSD: shmifvar.h,v 1.3 2010/08/12 21:41:47 pooka Exp $ */
/*-
* Copyright (c) 2009 Antti Kantee. All Rights Reserved.
@@ -37,12 +37,13 @@
uint32_t shm_magic;
uint32_t shm_version;
- uint32_t shm_gen;
+ uint64_t shm_gen;
+
uint32_t shm_first;
uint32_t shm_last;
uint32_t shm_lock;
- uint32_t shm_spare[2];
+ uint32_t shm_spare[1];
uint8_t shm_data[0];
};
@@ -51,4 +52,27 @@
#define IFMEM_WAKEUP (offsetof(struct shmif_mem, shm_version))
#define PKTLEN_SIZE (sizeof(uint32_t))
+#define BUSMEM_SIZE (1024*1024)
+#define BUSMEM_DATASIZE (BUSMEM_SIZE - sizeof(struct shmif_mem))
+
+#if 0
+#ifdef _KERNEL
+#define DPRINTF(x) rumpuser_dprintf x
+#else
+#define DPRINTF(x) printf x
+#endif
+#else
+#define DPRINTF(x)
+#endif
+
+void shmif_lockbus(struct shmif_mem *);
+void shmif_unlockbus(struct shmif_mem *);
+uint32_t shmif_advance(uint32_t, uint32_t);
+uint32_t shmif_busread(struct shmif_mem *,
+ void *, uint32_t, size_t, bool *);
+void shmif_advancefirst(struct shmif_mem *, uint32_t, size_t);
+uint32_t shmif_buswrite(struct shmif_mem *, uint32_t,
+ void *, size_t, bool *);
+uint32_t shmif_nextpktoff(struct shmif_mem *, uint32_t);
+
#endif
Added files:
Index: src/sys/rump/net/lib/libshmif/shmif_busops.c
diff -u /dev/null src/sys/rump/net/lib/libshmif/shmif_busops.c:1.1
--- /dev/null Thu Aug 12 21:41:47 2010
+++ src/sys/rump/net/lib/libshmif/shmif_busops.c Thu Aug 12 21:41:47 2010
@@ -0,0 +1,165 @@
+/* $NetBSD: shmif_busops.c,v 1.1 2010/08/12 21:41:47 pooka Exp $ */
+
+/*
+ * Copyright (c) 2009 Antti Kantee. All Rights Reserved.
+ *
+ * Development of this software was supported by The Nokia Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: shmif_busops.c,v 1.1 2010/08/12 21:41:47 pooka Exp $");
+
+#include <sys/param.h>
+#include <sys/atomic.h>
+
+#include "shmifvar.h"
+
+#ifndef _KERNEL
+#include <assert.h>
+#define KASSERT(a) assert(a)
+#else
+#include <rump/rumpuser.h>
+#endif
+
+#define LOCK_UNLOCKED 0
+#define LOCK_LOCKED 1
+
+/*
+ * This locking needs work and will misbehave severely if:
+ * 1) the backing memory has to be paged in
+ * 2) some lockholder exits while holding the lock
+ */
+void
+shmif_lockbus(struct shmif_mem *busmem)
+{
+
+ while (atomic_cas_32(&busmem->shm_lock,
+ LOCK_UNLOCKED, LOCK_LOCKED) == LOCK_LOCKED)
+ continue;
+ membar_enter();
+}
+
+void
+shmif_unlockbus(struct shmif_mem *busmem)
+{
+ unsigned int old;
+
+ membar_exit();
+ old = atomic_swap_32(&busmem->shm_lock, LOCK_UNLOCKED);
+ KASSERT(old == LOCK_LOCKED);
+}
+
+uint32_t
+shmif_advance(uint32_t oldoff, uint32_t delta)
+{
+ uint32_t newoff;
+
+ newoff = oldoff + delta;
+ if (newoff >= BUSMEM_DATASIZE)
+ newoff -= (BUSMEM_DATASIZE);
+ return newoff;
+
+}
+
+uint32_t
+shmif_busread(struct shmif_mem *busmem, void *dest, uint32_t off, size_t len,
+ bool *wrap)
+{
+ size_t chunk;
+
+ KASSERT(len < (BUSMEM_DATASIZE) && off <= BUSMEM_DATASIZE);
+ chunk = MIN(len, BUSMEM_DATASIZE - off);
+ memcpy(dest, busmem->shm_data + off, chunk);
+ len -= chunk;
+
+ if (len == 0)
+ return off + chunk;
+
+ /* else, wraps around */
+ off = 0;
+ *wrap = true;
+
+ /* finish reading */
+ memcpy((uint8_t *)dest + chunk, busmem->shm_data + off, len);
+ return off + len;
+}
+
+void
+shmif_advancefirst(struct shmif_mem *busmem, uint32_t off, size_t len)
+{
+
+ while (off <= busmem->shm_first + PKTLEN_SIZE
+ && off+len > busmem->shm_first) {
+ DPRINTF(("advancefirst: old offset %d, ", busmem->shm_first));
+ busmem->shm_first = shmif_nextpktoff(busmem, busmem->shm_first);
+ DPRINTF(("new offset: %d\n", busmem->shm_first));
+ }
+}
+
+uint32_t
+shmif_buswrite(struct shmif_mem *busmem, uint32_t off, void *data, size_t len,
+ bool *wrap)
+{
+ size_t chunk;
+
+ KASSERT(len < (BUSMEM_DATASIZE) && off <= BUSMEM_DATASIZE);
+
+ chunk = MIN(len, BUSMEM_DATASIZE - off);
+ len -= chunk;
+
+ shmif_advancefirst(busmem, off, chunk + (len ? 1 : 0));
+
+ memcpy(busmem->shm_data + off, data, chunk);
+
+ DPRINTF(("buswrite: wrote %d bytes to %d", chunk, off));
+
+ if (len == 0) {
+ DPRINTF(("\n"));
+ return off + chunk;
+ }
+
+ DPRINTF((", wrapped bytes %d to 0\n", len));
+
+ /* else, wraps around */
+ off = 0;
+ *wrap = true;
+
+ shmif_advancefirst(busmem, off, len);
+
+ /* finish writing */
+ memcpy(busmem->shm_data + off, (uint8_t *)data + chunk, len);
+ return off + len;
+}
+
+uint32_t
+shmif_nextpktoff(struct shmif_mem *busmem, uint32_t oldoff)
+{
+ uint32_t oldlen;
+ bool dummy;
+
+ shmif_busread(busmem, &oldlen, oldoff, PKTLEN_SIZE, &dummy);
+ KASSERT(oldlen < BUSMEM_DATASIZE);
+
+ return shmif_advance(oldoff, PKTLEN_SIZE + oldlen);
+}
