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freebsd-nq/sys/dev/netmap/netmap.c
Luigi Rizzo bcda432e01 indentation and whitespace fixes
2012-01-13 11:58:06 +00:00

1695 lines
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/*
* Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
*
* 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 AND CONTRIBUTORS ``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.
*/
/*
* $FreeBSD$
* $Id: netmap.c 9795 2011-12-02 11:39:08Z luigi $
*
* This module supports memory mapped access to network devices,
* see netmap(4).
*
* The module uses a large, memory pool allocated by the kernel
* and accessible as mmapped memory by multiple userspace threads/processes.
* The memory pool contains packet buffers and "netmap rings",
* i.e. user-accessible copies of the interface's queues.
*
* Access to the network card works like this:
* 1. a process/thread issues one or more open() on /dev/netmap, to create
* select()able file descriptor on which events are reported.
* 2. on each descriptor, the process issues an ioctl() to identify
* the interface that should report events to the file descriptor.
* 3. on each descriptor, the process issues an mmap() request to
* map the shared memory region within the process' address space.
* The list of interesting queues is indicated by a location in
* the shared memory region.
* 4. using the functions in the netmap(4) userspace API, a process
* can look up the occupation state of a queue, access memory buffers,
* and retrieve received packets or enqueue packets to transmit.
* 5. using some ioctl()s the process can synchronize the userspace view
* of the queue with the actual status in the kernel. This includes both
* receiving the notification of new packets, and transmitting new
* packets on the output interface.
* 6. select() or poll() can be used to wait for events on individual
* transmit or receive queues (or all queues for a given interface).
*/
#include <sys/cdefs.h> /* prerequisite */
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/module.h>
#include <sys/errno.h>
#include <sys/param.h> /* defines used in kernel.h */
#include <sys/jail.h>
#include <sys/kernel.h> /* types used in module initialization */
#include <sys/conf.h> /* cdevsw struct */
#include <sys/uio.h> /* uio struct */
#include <sys/sockio.h>
#include <sys/socketvar.h> /* struct socket */
#include <sys/malloc.h>
#include <sys/mman.h> /* PROT_EXEC */
#include <sys/poll.h>
#include <sys/proc.h>
#include <vm/vm.h> /* vtophys */
#include <vm/pmap.h> /* vtophys */
#include <sys/socket.h> /* sockaddrs */
#include <machine/bus.h>
#include <sys/selinfo.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/bpf.h> /* BIOCIMMEDIATE */
#include <net/vnet.h>
#include <net/netmap.h>
#include <dev/netmap/netmap_kern.h>
#include <machine/bus.h> /* bus_dmamap_* */
MALLOC_DEFINE(M_NETMAP, "netmap", "Network memory map");
/*
* lock and unlock for the netmap memory allocator
*/
#define NMA_LOCK() mtx_lock(&netmap_mem_d->nm_mtx);
#define NMA_UNLOCK() mtx_unlock(&netmap_mem_d->nm_mtx);
/*
* Default amount of memory pre-allocated by the module.
* We start with a large size and then shrink our demand
* according to what is avalable when the module is loaded.
* At the moment the block is contiguous, but we can easily
* restrict our demand to smaller units (16..64k)
*/
#define NETMAP_MEMORY_SIZE (64 * 1024 * PAGE_SIZE)
static void * netmap_malloc(size_t size, const char *msg);
static void netmap_free(void *addr, const char *msg);
#define netmap_if_malloc(len) netmap_malloc(len, "nifp")
#define netmap_if_free(v) netmap_free((v), "nifp")
#define netmap_ring_malloc(len) netmap_malloc(len, "ring")
#define netmap_free_rings(na) \
netmap_free((na)->tx_rings[0].ring, "shadow rings");
/*
* Allocator for a pool of packet buffers. For each buffer we have
* one entry in the bitmap to signal the state. Allocation scans
* the bitmap, but since this is done only on attach, we are not
* too worried about performance
* XXX if we need to allocate small blocks, a translation
* table is used both for kernel virtual address and physical
* addresses.
*/
struct netmap_buf_pool {
u_int total_buffers; /* total buffers. */
u_int free;
u_int bufsize;
char *base; /* buffer base address */
uint32_t *bitmap; /* one bit per buffer, 1 means free */
};
struct netmap_buf_pool nm_buf_pool;
/* XXX move these two vars back into netmap_buf_pool */
u_int netmap_total_buffers;
char *netmap_buffer_base; /* address of an invalid buffer */
/* user-controlled variables */
int netmap_verbose;
static int no_timestamp; /* don't timestamp on rxsync */
SYSCTL_NODE(_dev, OID_AUTO, netmap, CTLFLAG_RW, 0, "Netmap args");
SYSCTL_INT(_dev_netmap, OID_AUTO, verbose,
CTLFLAG_RW, &netmap_verbose, 0, "Verbose mode");
SYSCTL_INT(_dev_netmap, OID_AUTO, no_timestamp,
CTLFLAG_RW, &no_timestamp, 0, "no_timestamp");
SYSCTL_INT(_dev_netmap, OID_AUTO, total_buffers,
CTLFLAG_RD, &nm_buf_pool.total_buffers, 0, "total_buffers");
SYSCTL_INT(_dev_netmap, OID_AUTO, free_buffers,
CTLFLAG_RD, &nm_buf_pool.free, 0, "free_buffers");
/*
* Allocate n buffers from the ring, and fill the slot.
* Buffer 0 is the 'junk' buffer.
*/
static void
netmap_new_bufs(struct netmap_if *nifp __unused,
struct netmap_slot *slot, u_int n)
{
struct netmap_buf_pool *p = &nm_buf_pool;
uint32_t bi = 0; /* index in the bitmap */
uint32_t mask, j, i = 0; /* slot counter */
if (n > p->free) {
D("only %d out of %d buffers available", i, n);
return;
}
/* termination is guaranteed by p->free */
while (i < n && p->free > 0) {
uint32_t cur = p->bitmap[bi];
if (cur == 0) { /* bitmask is fully used */
bi++;
continue;
}
/* locate a slot */
for (j = 0, mask = 1; (cur & mask) == 0; j++, mask <<= 1) ;
p->bitmap[bi] &= ~mask; /* slot in use */
p->free--;
slot[i].buf_idx = bi*32+j;
slot[i].len = p->bufsize;
slot[i].flags = NS_BUF_CHANGED;
i++;
}
ND("allocated %d buffers, %d available", n, p->free);
}
static void
netmap_free_buf(struct netmap_if *nifp __unused, uint32_t i)
{
struct netmap_buf_pool *p = &nm_buf_pool;
uint32_t pos, mask;
if (i >= p->total_buffers) {
D("invalid free index %d", i);
return;
}
pos = i / 32;
mask = 1 << (i % 32);
if (p->bitmap[pos] & mask) {
D("slot %d already free", i);
return;
}
p->bitmap[pos] |= mask;
p->free++;
}
/* Descriptor of the memory objects handled by our memory allocator. */
struct netmap_mem_obj {
TAILQ_ENTRY(netmap_mem_obj) nmo_next; /* next object in the
chain. */
int nmo_used; /* flag set on used memory objects. */
size_t nmo_size; /* size of the memory area reserved for the
object. */
void *nmo_data; /* pointer to the memory area. */
};
/* Wrap our memory objects to make them ``chainable``. */
TAILQ_HEAD(netmap_mem_obj_h, netmap_mem_obj);
/* Descriptor of our custom memory allocator. */
struct netmap_mem_d {
struct mtx nm_mtx; /* lock used to handle the chain of memory
objects. */
struct netmap_mem_obj_h nm_molist; /* list of memory objects */
size_t nm_size; /* total amount of memory used for rings etc. */
size_t nm_totalsize; /* total amount of allocated memory
(the difference is used for buffers) */
size_t nm_buf_start; /* offset of packet buffers.
This is page-aligned. */
size_t nm_buf_len; /* total memory for buffers */
void *nm_buffer; /* pointer to the whole pre-allocated memory
area. */
};
/* Structure associated to each thread which registered an interface. */
struct netmap_priv_d {
struct netmap_if *np_nifp; /* netmap interface descriptor. */
struct ifnet *np_ifp; /* device for which we hold a reference */
int np_ringid; /* from the ioctl */
u_int np_qfirst, np_qlast; /* range of rings to scan */
uint16_t np_txpoll;
};
/* Shorthand to compute a netmap interface offset. */
#define netmap_if_offset(v) \
((char *) (v) - (char *) netmap_mem_d->nm_buffer)
/* .. and get a physical address given a memory offset */
#define netmap_ofstophys(o) \
(vtophys(netmap_mem_d->nm_buffer) + (o))
static struct cdev *netmap_dev; /* /dev/netmap character device. */
static struct netmap_mem_d *netmap_mem_d; /* Our memory allocator. */
static d_mmap_t netmap_mmap;
static d_ioctl_t netmap_ioctl;
static d_poll_t netmap_poll;
#ifdef NETMAP_KEVENT
static d_kqfilter_t netmap_kqfilter;
#endif
static struct cdevsw netmap_cdevsw = {
.d_version = D_VERSION,
.d_name = "netmap",
.d_mmap = netmap_mmap,
.d_ioctl = netmap_ioctl,
.d_poll = netmap_poll,
#ifdef NETMAP_KEVENT
.d_kqfilter = netmap_kqfilter,
#endif
};
#ifdef NETMAP_KEVENT
static int netmap_kqread(struct knote *, long);
static int netmap_kqwrite(struct knote *, long);
static void netmap_kqdetach(struct knote *);
static struct filterops netmap_read_filterops = {
.f_isfd = 1,
.f_attach = NULL,
.f_detach = netmap_kqdetach,
.f_event = netmap_kqread,
};
static struct filterops netmap_write_filterops = {
.f_isfd = 1,
.f_attach = NULL,
.f_detach = netmap_kqdetach,
.f_event = netmap_kqwrite,
};
/*
* support for the kevent() system call.
*
* This is the kevent filter, and is executed each time a new event
* is triggered on the device. This function execute some operation
* depending on the received filter.
*
* The implementation should test the filters and should implement
* filter operations we are interested on (a full list in /sys/event.h).
*
* On a match we should:
* - set kn->kn_fop
* - set kn->kn_hook
* - call knlist_add() to deliver the event to the application.
*
* Return 0 if the event should be delivered to the application.
*/
static int
netmap_kqfilter(struct cdev *dev, struct knote *kn)
{
/* declare variables needed to read/write */
switch(kn->kn_filter) {
case EVFILT_READ:
if (netmap_verbose)
D("%s kqfilter: EVFILT_READ" ifp->if_xname);
/* read operations */
kn->kn_fop = &netmap_read_filterops;
break;
case EVFILT_WRITE:
if (netmap_verbose)
D("%s kqfilter: EVFILT_WRITE" ifp->if_xname);
/* write operations */
kn->kn_fop = &netmap_write_filterops;
break;
default:
if (netmap_verbose)
D("%s kqfilter: invalid filter" ifp->if_xname);
return(EINVAL);
}
kn->kn_hook = 0;//
knlist_add(&netmap_sc->tun_rsel.si_note, kn, 0);
return (0);
}
#endif /* NETMAP_KEVENT */
/*
* File descriptor's private data destructor.
*
* Call nm_register(ifp,0) to stop netmap mode on the interface and
* revert to normal operation. We expect that np_ifp has not gone.
*/
static void
netmap_dtor(void *data)
{
struct netmap_priv_d *priv = data;
struct ifnet *ifp = priv->np_ifp;
struct netmap_adapter *na = NA(ifp);
struct netmap_if *nifp = priv->np_nifp;
if (0)
printf("%s starting for %p ifp %p\n", __FUNCTION__, priv,
priv ? priv->np_ifp : NULL);
na->nm_lock(ifp->if_softc, NETMAP_CORE_LOCK, 0);
na->refcount--;
if (na->refcount <= 0) { /* last instance */
u_int i;
D("deleting last netmap instance for %s", ifp->if_xname);
/*
* there is a race here with *_netmap_task() and
* netmap_poll(), which don't run under NETMAP_CORE_LOCK.
* na->refcount == 0 && na->ifp->if_capenable & IFCAP_NETMAP
* (aka NETMAP_DELETING(na)) are a unique marker that the
* device is dying.
* Before destroying stuff we sleep a bit, and then complete
* the job. NIOCREG should realize the condition and
* loop until they can continue; the other routines
* should check the condition at entry and quit if
* they cannot run.
*/
na->nm_lock(ifp->if_softc, NETMAP_CORE_UNLOCK, 0);
tsleep(na, 0, "NIOCUNREG", 4);
na->nm_lock(ifp->if_softc, NETMAP_CORE_LOCK, 0);
na->nm_register(ifp, 0); /* off, clear IFCAP_NETMAP */
/* Wake up any sleeping threads. netmap_poll will
* then return POLLERR
*/
for (i = 0; i < na->num_queues + 2; i++) {
selwakeuppri(&na->tx_rings[i].si, PI_NET);
selwakeuppri(&na->rx_rings[i].si, PI_NET);
}
/* release all buffers */
NMA_LOCK();
for (i = 0; i < na->num_queues + 1; i++) {
int j, lim;
struct netmap_ring *ring;
ND("tx queue %d", i);
ring = na->tx_rings[i].ring;
lim = na->tx_rings[i].nkr_num_slots;
for (j = 0; j < lim; j++)
netmap_free_buf(nifp, ring->slot[j].buf_idx);
ND("rx queue %d", i);
ring = na->rx_rings[i].ring;
lim = na->rx_rings[i].nkr_num_slots;
for (j = 0; j < lim; j++)
netmap_free_buf(nifp, ring->slot[j].buf_idx);
}
NMA_UNLOCK();
netmap_free_rings(na);
wakeup(na);
}
netmap_if_free(nifp);
na->nm_lock(ifp->if_softc, NETMAP_CORE_UNLOCK, 0);
if_rele(ifp);
bzero(priv, sizeof(*priv)); /* XXX for safety */
free(priv, M_DEVBUF);
}
/*
* Create and return a new ``netmap_if`` object, and possibly also
* rings and packet buffors.
*
* Return NULL on failure.
*/
static void *
netmap_if_new(const char *ifname, struct netmap_adapter *na)
{
struct netmap_if *nifp;
struct netmap_ring *ring;
char *buff;
u_int i, len, ofs;
u_int n = na->num_queues + 1; /* shorthand, include stack queue */
/*
* the descriptor is followed inline by an array of offsets
* to the tx and rx rings in the shared memory region.
*/
len = sizeof(struct netmap_if) + 2 * n * sizeof(ssize_t);
nifp = netmap_if_malloc(len);
if (nifp == NULL)
return (NULL);
/* initialize base fields */
*(int *)(uintptr_t)&nifp->ni_num_queues = na->num_queues;
strncpy(nifp->ni_name, ifname, IFNAMSIZ);
(na->refcount)++; /* XXX atomic ? we are under lock */
if (na->refcount > 1)
goto final;
/*
* If this is the first instance, allocate the shadow rings and
* buffers for this card (one for each hw queue, one for the host).
* The rings are contiguous, but have variable size.
* The entire block is reachable at
* na->tx_rings[0].ring
*/
len = n * (2 * sizeof(struct netmap_ring) +
(na->num_tx_desc + na->num_rx_desc) *
sizeof(struct netmap_slot) );
buff = netmap_ring_malloc(len);
if (buff == NULL) {
D("failed to allocate %d bytes for %s shadow ring",
len, ifname);
error:
(na->refcount)--;
netmap_if_free(nifp);
return (NULL);
}
/* do we have the bufers ? we are in need of num_tx_desc buffers for
* each tx ring and num_tx_desc buffers for each rx ring. */
len = n * (na->num_tx_desc + na->num_rx_desc);
NMA_LOCK();
if (nm_buf_pool.free < len) {
NMA_UNLOCK();
netmap_free(buff, "not enough bufs");
goto error;
}
/*
* in the kring, store the pointers to the shared rings
* and initialize the rings. We are under NMA_LOCK().
*/
ofs = 0;
for (i = 0; i < n; i++) {
struct netmap_kring *kring;
int numdesc;
/* Transmit rings */
kring = &na->tx_rings[i];
numdesc = na->num_tx_desc;
bzero(kring, sizeof(*kring));
kring->na = na;
ring = kring->ring = (struct netmap_ring *)(buff + ofs);
*(ssize_t *)(uintptr_t)&ring->buf_ofs =
nm_buf_pool.base - (char *)ring;
ND("txring[%d] at %p ofs %d", i, ring, ring->buf_ofs);
*(int *)(int *)(uintptr_t)&ring->num_slots =
kring->nkr_num_slots = numdesc;
/*
* IMPORTANT:
* Always keep one slot empty, so we can detect new
* transmissions comparing cur and nr_hwcur (they are
* the same only if there are no new transmissions).
*/
ring->avail = kring->nr_hwavail = numdesc - 1;
ring->cur = kring->nr_hwcur = 0;
netmap_new_bufs(nifp, ring->slot, numdesc);
ofs += sizeof(struct netmap_ring) +
numdesc * sizeof(struct netmap_slot);
/* Receive rings */
kring = &na->rx_rings[i];
numdesc = na->num_rx_desc;
bzero(kring, sizeof(*kring));
kring->na = na;
ring = kring->ring = (struct netmap_ring *)(buff + ofs);
*(ssize_t *)(uintptr_t)&ring->buf_ofs =
nm_buf_pool.base - (char *)ring;
ND("rxring[%d] at %p offset %d", i, ring, ring->buf_ofs);
*(int *)(int *)(uintptr_t)&ring->num_slots =
kring->nkr_num_slots = numdesc;
ring->cur = kring->nr_hwcur = 0;
ring->avail = kring->nr_hwavail = 0; /* empty */
netmap_new_bufs(nifp, ring->slot, numdesc);
ofs += sizeof(struct netmap_ring) +
numdesc * sizeof(struct netmap_slot);
}
NMA_UNLOCK();
for (i = 0; i < n+1; i++) {
// XXX initialize the selrecord structs.
}
final:
/*
* fill the slots for the rx and tx queues. They contain the offset
* between the ring and nifp, so the information is usable in
* userspace to reach the ring from the nifp.
*/
for (i = 0; i < n; i++) {
char *base = (char *)nifp;
*(ssize_t *)(uintptr_t)&nifp->ring_ofs[i] =
(char *)na->tx_rings[i].ring - base;
*(ssize_t *)(uintptr_t)&nifp->ring_ofs[i+n] =
(char *)na->rx_rings[i].ring - base;
}
return (nifp);
}
/*
* mmap(2) support for the "netmap" device.
*
* Expose all the memory previously allocated by our custom memory
* allocator: this way the user has only to issue a single mmap(2), and
* can work on all the data structures flawlessly.
*
* Return 0 on success, -1 otherwise.
*/
static int
#if __FreeBSD_version < 900000
netmap_mmap(__unused struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr,
int nprot)
#else
netmap_mmap(__unused struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
int nprot, __unused vm_memattr_t *memattr)
#endif
{
if (nprot & PROT_EXEC)
return (-1); // XXX -1 or EINVAL ?
ND("request for offset 0x%x", (uint32_t)offset);
*paddr = netmap_ofstophys(offset);
return (0);
}
/*
* Handlers for synchronization of the queues from/to the host.
*
* netmap_sync_to_host() passes packets up. We are called from a
* system call in user process context, and the only contention
* can be among multiple user threads erroneously calling
* this routine concurrently. In principle we should not even
* need to lock.
*/
static void
netmap_sync_to_host(struct netmap_adapter *na)
{
struct netmap_kring *kring = &na->tx_rings[na->num_queues];
struct netmap_ring *ring = kring->ring;
struct mbuf *head = NULL, *tail = NULL, *m;
u_int k, n, lim = kring->nkr_num_slots - 1;
k = ring->cur;
if (k > lim) {
netmap_ring_reinit(kring);
return;
}
// na->nm_lock(na->ifp->if_softc, NETMAP_CORE_LOCK, 0);
/* Take packets from hwcur to cur and pass them up.
* In case of no buffers we give up. At the end of the loop,
* the queue is drained in all cases.
*/
for (n = kring->nr_hwcur; n != k;) {
struct netmap_slot *slot = &ring->slot[n];
n = (n == lim) ? 0 : n + 1;
if (slot->len < 14 || slot->len > NETMAP_BUF_SIZE) {
D("bad pkt at %d len %d", n, slot->len);
continue;
}
m = m_devget(NMB(slot), slot->len, 0, na->ifp, NULL);
if (m == NULL)
break;
if (tail)
tail->m_nextpkt = m;
else
head = m;
tail = m;
m->m_nextpkt = NULL;
}
kring->nr_hwcur = k;
kring->nr_hwavail = ring->avail = lim;
// na->nm_lock(na->ifp->if_softc, NETMAP_CORE_UNLOCK, 0);
/* send packets up, outside the lock */
while ((m = head) != NULL) {
head = head->m_nextpkt;
m->m_nextpkt = NULL;
m->m_pkthdr.rcvif = na->ifp;
if (netmap_verbose & NM_VERB_HOST)
D("sending up pkt %p size %d", m, m->m_pkthdr.len);
(na->ifp->if_input)(na->ifp, m);
}
}
/*
* rxsync backend for packets coming from the host stack.
* They have been put in the queue by netmap_start() so we
* need to protect access to the kring using a lock.
*
* This routine also does the selrecord if called from the poll handler
* (we know because td != NULL).
*/
static void
netmap_sync_from_host(struct netmap_adapter *na, struct thread *td)
{
struct netmap_kring *kring = &na->rx_rings[na->num_queues];
struct netmap_ring *ring = kring->ring;
int error = 1, delta;
u_int k = ring->cur, lim = kring->nkr_num_slots;
na->nm_lock(na->ifp->if_softc, NETMAP_CORE_LOCK, 0);
if (k >= lim) /* bad value */
goto done;
delta = k - kring->nr_hwcur;
if (delta < 0)
delta += lim;
kring->nr_hwavail -= delta;
if (kring->nr_hwavail < 0) /* error */
goto done;
kring->nr_hwcur = k;
error = 0;
k = ring->avail = kring->nr_hwavail;
if (k == 0 && td)
selrecord(td, &kring->si);
if (k && (netmap_verbose & NM_VERB_HOST))
D("%d pkts from stack", k);
done:
na->nm_lock(na->ifp->if_softc, NETMAP_CORE_UNLOCK, 0);
if (error)
netmap_ring_reinit(kring);
}
/*
* get a refcounted reference to an interface.
* Return ENXIO if the interface does not exist, EINVAL if netmap
* is not supported by the interface.
* If successful, hold a reference.
*/
static int
get_ifp(const char *name, struct ifnet **ifp)
{
*ifp = ifunit_ref(name);
if (*ifp == NULL)
return (ENXIO);
/* can do this if the capability exists and if_pspare[0]
* points to the netmap descriptor.
*/
if ((*ifp)->if_capabilities & IFCAP_NETMAP && NA(*ifp))
return 0; /* valid pointer, we hold the refcount */
if_rele(*ifp);
return EINVAL; // not NETMAP capable
}
/*
* Error routine called when txsync/rxsync detects an error.
* Can't do much more than resetting cur = hwcur, avail = hwavail.
* Return 1 on reinit.
*
* This routine is only called by the upper half of the kernel.
* It only reads hwcur (which is changed only by the upper half, too)
* and hwavail (which may be changed by the lower half, but only on
* a tx ring and only to increase it, so any error will be recovered
* on the next call). For the above, we don't strictly need to call
* it under lock.
*/
int
netmap_ring_reinit(struct netmap_kring *kring)
{
struct netmap_ring *ring = kring->ring;
u_int i, lim = kring->nkr_num_slots - 1;
int errors = 0;
D("called for %s", kring->na->ifp->if_xname);
if (ring->cur > lim)
errors++;
for (i = 0; i <= lim; i++) {
u_int idx = ring->slot[i].buf_idx;
u_int len = ring->slot[i].len;
if (idx < 2 || idx >= netmap_total_buffers) {
if (!errors++)
D("bad buffer at slot %d idx %d len %d ", i, idx, len);
ring->slot[i].buf_idx = 0;
ring->slot[i].len = 0;
} else if (len > NETMAP_BUF_SIZE) {
ring->slot[i].len = 0;
if (!errors++)
D("bad len %d at slot %d idx %d",
len, i, idx);
}
}
if (errors) {
int pos = kring - kring->na->tx_rings;
int n = kring->na->num_queues + 2;
D("total %d errors", errors);
errors++;
D("%s %s[%d] reinit, cur %d -> %d avail %d -> %d",
kring->na->ifp->if_xname,
pos < n ? "TX" : "RX", pos < n ? pos : pos - n,
ring->cur, kring->nr_hwcur,
ring->avail, kring->nr_hwavail);
ring->cur = kring->nr_hwcur;
ring->avail = kring->nr_hwavail;
}
return (errors ? 1 : 0);
}
/*
* Set the ring ID. For devices with a single queue, a request
* for all rings is the same as a single ring.
*/
static int
netmap_set_ringid(struct netmap_priv_d *priv, u_int ringid)
{
struct ifnet *ifp = priv->np_ifp;
struct netmap_adapter *na = NA(ifp);
void *adapter = na->ifp->if_softc; /* shorthand */
u_int i = ringid & NETMAP_RING_MASK;
/* first time we don't lock */
int need_lock = (priv->np_qfirst != priv->np_qlast);
if ( (ringid & NETMAP_HW_RING) && i >= na->num_queues) {
D("invalid ring id %d", i);
return (EINVAL);
}
if (need_lock)
na->nm_lock(adapter, NETMAP_CORE_LOCK, 0);
priv->np_ringid = ringid;
if (ringid & NETMAP_SW_RING) {
priv->np_qfirst = na->num_queues;
priv->np_qlast = na->num_queues + 1;
} else if (ringid & NETMAP_HW_RING) {
priv->np_qfirst = i;
priv->np_qlast = i + 1;
} else {
priv->np_qfirst = 0;
priv->np_qlast = na->num_queues;
}
priv->np_txpoll = (ringid & NETMAP_NO_TX_POLL) ? 0 : 1;
if (need_lock)
na->nm_lock(adapter, NETMAP_CORE_UNLOCK, 0);
if (ringid & NETMAP_SW_RING)
D("ringid %s set to SW RING", ifp->if_xname);
else if (ringid & NETMAP_HW_RING)
D("ringid %s set to HW RING %d", ifp->if_xname,
priv->np_qfirst);
else
D("ringid %s set to all %d HW RINGS", ifp->if_xname,
priv->np_qlast);
return 0;
}
/*
* ioctl(2) support for the "netmap" device.
*
* Following a list of accepted commands:
* - NIOCGINFO
* - SIOCGIFADDR just for convenience
* - NIOCREGIF
* - NIOCUNREGIF
* - NIOCTXSYNC
* - NIOCRXSYNC
*
* Return 0 on success, errno otherwise.
*/
static int
netmap_ioctl(__unused struct cdev *dev, u_long cmd, caddr_t data,
__unused int fflag, struct thread *td)
{
struct netmap_priv_d *priv = NULL;
struct ifnet *ifp;
struct nmreq *nmr = (struct nmreq *) data;
struct netmap_adapter *na;
void *adapter;
int error;
u_int i;
struct netmap_if *nifp;
CURVNET_SET(TD_TO_VNET(td));
error = devfs_get_cdevpriv((void **)&priv);
if (error != ENOENT && error != 0) {
CURVNET_RESTORE();
return (error);
}
error = 0; /* Could be ENOENT */
switch (cmd) {
case NIOCGINFO: /* return capabilities etc */
/* memsize is always valid */
nmr->nr_memsize = netmap_mem_d->nm_totalsize;
nmr->nr_offset = 0;
nmr->nr_numrings = 0;
nmr->nr_numslots = 0;
if (nmr->nr_name[0] == '\0') /* just get memory info */
break;
error = get_ifp(nmr->nr_name, &ifp); /* get a refcount */
if (error)
break;
na = NA(ifp); /* retrieve netmap_adapter */
nmr->nr_numrings = na->num_queues;
nmr->nr_numslots = na->num_tx_desc;
if_rele(ifp); /* return the refcount */
break;
case NIOCREGIF:
if (priv != NULL) { /* thread already registered */
error = netmap_set_ringid(priv, nmr->nr_ringid);
break;
}
/* find the interface and a reference */
error = get_ifp(nmr->nr_name, &ifp); /* keep reference */
if (error)
break;
na = NA(ifp); /* retrieve netmap adapter */
adapter = na->ifp->if_softc; /* shorthand */
/*
* Allocate the private per-thread structure.
* XXX perhaps we can use a blocking malloc ?
*/
priv = malloc(sizeof(struct netmap_priv_d), M_DEVBUF,
M_NOWAIT | M_ZERO);
if (priv == NULL) {
error = ENOMEM;
if_rele(ifp); /* return the refcount */
break;
}
for (i = 10; i > 0; i--) {
na->nm_lock(adapter, NETMAP_CORE_LOCK, 0);
if (!NETMAP_DELETING(na))
break;
na->nm_lock(adapter, NETMAP_CORE_UNLOCK, 0);
tsleep(na, 0, "NIOCREGIF", hz/10);
}
if (i == 0) {
D("too many NIOCREGIF attempts, give up");
error = EINVAL;
free(priv, M_DEVBUF);
if_rele(ifp); /* return the refcount */
break;
}
priv->np_ifp = ifp; /* store the reference */
error = netmap_set_ringid(priv, nmr->nr_ringid);
if (error)
goto error;
priv->np_nifp = nifp = netmap_if_new(nmr->nr_name, na);
if (nifp == NULL) { /* allocation failed */
error = ENOMEM;
} else if (ifp->if_capenable & IFCAP_NETMAP) {
/* was already set */
} else {
/* Otherwise set the card in netmap mode
* and make it use the shared buffers.
*/
error = na->nm_register(ifp, 1); /* mode on */
if (error) {
/*
* do something similar to netmap_dtor().
*/
netmap_free_rings(na);
// XXX tx_rings is inline, must not be freed.
// free(na->tx_rings, M_DEVBUF); // XXX wrong ?
na->tx_rings = na->rx_rings = NULL;
na->refcount--;
netmap_if_free(nifp);
nifp = NULL;
}
}
if (error) { /* reg. failed, release priv and ref */
error:
na->nm_lock(adapter, NETMAP_CORE_UNLOCK, 0);
free(priv, M_DEVBUF);
if_rele(ifp); /* return the refcount */
break;
}
na->nm_lock(adapter, NETMAP_CORE_UNLOCK, 0);
error = devfs_set_cdevpriv(priv, netmap_dtor);
if (error != 0) {
/* could not assign the private storage for the
* thread, call the destructor explicitly.
*/
netmap_dtor(priv);
break;
}
/* return the offset of the netmap_if object */
nmr->nr_numrings = na->num_queues;
nmr->nr_numslots = na->num_tx_desc;
nmr->nr_memsize = netmap_mem_d->nm_totalsize;
nmr->nr_offset = netmap_if_offset(nifp);
break;
case NIOCUNREGIF:
if (priv == NULL) {
error = ENXIO;
break;
}
/* the interface is unregistered inside the
destructor of the private data. */
devfs_clear_cdevpriv();
break;
case NIOCTXSYNC:
case NIOCRXSYNC:
if (priv == NULL) {
error = ENXIO;
break;
}
ifp = priv->np_ifp; /* we have a reference */
na = NA(ifp); /* retrieve netmap adapter */
adapter = ifp->if_softc; /* shorthand */
if (priv->np_qfirst == na->num_queues) {
/* queues to/from host */
if (cmd == NIOCTXSYNC)
netmap_sync_to_host(na);
else
netmap_sync_from_host(na, NULL);
break;
}
for (i = priv->np_qfirst; i < priv->np_qlast; i++) {
if (cmd == NIOCTXSYNC) {
struct netmap_kring *kring = &na->tx_rings[i];
if (netmap_verbose & NM_VERB_TXSYNC)
D("sync tx ring %d cur %d hwcur %d",
i, kring->ring->cur,
kring->nr_hwcur);
na->nm_txsync(adapter, i, 1 /* do lock */);
if (netmap_verbose & NM_VERB_TXSYNC)
D("after sync tx ring %d cur %d hwcur %d",
i, kring->ring->cur,
kring->nr_hwcur);
} else {
na->nm_rxsync(adapter, i, 1 /* do lock */);
microtime(&na->rx_rings[i].ring->ts);
}
}
break;
case BIOCIMMEDIATE:
case BIOCGHDRCMPLT:
case BIOCSHDRCMPLT:
case BIOCSSEESENT:
D("ignore BIOCIMMEDIATE/BIOCSHDRCMPLT/BIOCSHDRCMPLT/BIOCSSEESENT");
break;
default:
{
/*
* allow device calls
*/
struct socket so;
bzero(&so, sizeof(so));
error = get_ifp(nmr->nr_name, &ifp); /* keep reference */
if (error)
break;
so.so_vnet = ifp->if_vnet;
// so->so_proto not null.
error = ifioctl(&so, cmd, data, td);
if_rele(ifp);
}
}
CURVNET_RESTORE();
return (error);
}
/*
* select(2) and poll(2) handlers for the "netmap" device.
*
* Can be called for one or more queues.
* Return true the event mask corresponding to ready events.
* If there are no ready events, do a selrecord on either individual
* selfd or on the global one.
* Device-dependent parts (locking and sync of tx/rx rings)
* are done through callbacks.
*/
static int
netmap_poll(__unused struct cdev *dev, int events, struct thread *td)
{
struct netmap_priv_d *priv = NULL;
struct netmap_adapter *na;
struct ifnet *ifp;
struct netmap_kring *kring;
u_int core_lock, i, check_all, want_tx, want_rx, revents = 0;
void *adapter;
enum {NO_CL, NEED_CL, LOCKED_CL }; /* see below */
if (devfs_get_cdevpriv((void **)&priv) != 0 || priv == NULL)
return POLLERR;
ifp = priv->np_ifp;
// XXX check for deleting() ?
if ( (ifp->if_capenable & IFCAP_NETMAP) == 0)
return POLLERR;
if (netmap_verbose & 0x8000)
D("device %s events 0x%x", ifp->if_xname, events);
want_tx = events & (POLLOUT | POLLWRNORM);
want_rx = events & (POLLIN | POLLRDNORM);
adapter = ifp->if_softc;
na = NA(ifp); /* retrieve netmap adapter */
/* how many queues we are scanning */
i = priv->np_qfirst;
if (i == na->num_queues) { /* from/to host */
if (priv->np_txpoll || want_tx) {
/* push any packets up, then we are always ready */
kring = &na->tx_rings[i];
netmap_sync_to_host(na);
revents |= want_tx;
}
if (want_rx) {
kring = &na->rx_rings[i];
if (kring->ring->avail == 0)
netmap_sync_from_host(na, td);
if (kring->ring->avail > 0) {
revents |= want_rx;
}
}
return (revents);
}
/*
* check_all is set if the card has more than one queue and
* the client is polling all of them. If true, we sleep on
* the "global" selfd, otherwise we sleep on individual selfd
* (we can only sleep on one of them per direction).
* The interrupt routine in the driver should always wake on
* the individual selfd, and also on the global one if the card
* has more than one ring.
*
* If the card has only one lock, we just use that.
* If the card has separate ring locks, we just use those
* unless we are doing check_all, in which case the whole
* loop is wrapped by the global lock.
* We acquire locks only when necessary: if poll is called
* when buffers are available, we can just return without locks.
*
* rxsync() is only called if we run out of buffers on a POLLIN.
* txsync() is called if we run out of buffers on POLLOUT, or
* there are pending packets to send. The latter can be disabled
* passing NETMAP_NO_TX_POLL in the NIOCREG call.
*/
check_all = (i + 1 != priv->np_qlast);
/*
* core_lock indicates what to do with the core lock.
* The core lock is used when either the card has no individual
* locks, or it has individual locks but we are cheking all
* rings so we need the core lock to avoid missing wakeup events.
*
* It has three possible states:
* NO_CL we don't need to use the core lock, e.g.
* because we are protected by individual locks.
* NEED_CL we need the core lock. In this case, when we
* call the lock routine, move to LOCKED_CL
* to remember to release the lock once done.
* LOCKED_CL core lock is set, so we need to release it.
*/
core_lock = (check_all || !na->separate_locks) ? NEED_CL : NO_CL;
/*
* We start with a lock free round which is good if we have
* data available. If this fails, then lock and call the sync
* routines.
*/
for (i = priv->np_qfirst; want_rx && i < priv->np_qlast; i++) {
kring = &na->rx_rings[i];
if (kring->ring->avail > 0) {
revents |= want_rx;
want_rx = 0; /* also breaks the loop */
}
}
for (i = priv->np_qfirst; want_tx && i < priv->np_qlast; i++) {
kring = &na->tx_rings[i];
if (kring->ring->avail > 0) {
revents |= want_tx;
want_tx = 0; /* also breaks the loop */
}
}
/*
* If we to push packets out (priv->np_txpoll) or want_tx is
* still set, we do need to run the txsync calls (on all rings,
* to avoid that the tx rings stall).
*/
if (priv->np_txpoll || want_tx) {
for (i = priv->np_qfirst; i < priv->np_qlast; i++) {
kring = &na->tx_rings[i];
if (!want_tx && kring->ring->cur == kring->nr_hwcur)
continue;
if (core_lock == NEED_CL) {
na->nm_lock(adapter, NETMAP_CORE_LOCK, 0);
core_lock = LOCKED_CL;
}
if (na->separate_locks)
na->nm_lock(adapter, NETMAP_TX_LOCK, i);
if (netmap_verbose & NM_VERB_TXSYNC)
D("send %d on %s %d",
kring->ring->cur,
ifp->if_xname, i);
if (na->nm_txsync(adapter, i, 0 /* no lock */))
revents |= POLLERR;
if (want_tx) {
if (kring->ring->avail > 0) {
/* stop at the first ring. We don't risk
* starvation.
*/
revents |= want_tx;
want_tx = 0;
} else if (!check_all)
selrecord(td, &kring->si);
}
if (na->separate_locks)
na->nm_lock(adapter, NETMAP_TX_UNLOCK, i);
}
}
/*
* now if want_rx is still set we need to lock and rxsync.
* Do it on all rings because otherwise we starve.
*/
if (want_rx) {
for (i = priv->np_qfirst; i < priv->np_qlast; i++) {
kring = &na->rx_rings[i];
if (core_lock == NEED_CL) {
na->nm_lock(adapter, NETMAP_CORE_LOCK, 0);
core_lock = LOCKED_CL;
}
if (na->separate_locks)
na->nm_lock(adapter, NETMAP_RX_LOCK, i);
if (na->nm_rxsync(adapter, i, 0 /* no lock */))
revents |= POLLERR;
if (no_timestamp == 0 ||
kring->ring->flags & NR_TIMESTAMP)
microtime(&kring->ring->ts);
if (kring->ring->avail > 0)
revents |= want_rx;
else if (!check_all)
selrecord(td, &kring->si);
if (na->separate_locks)
na->nm_lock(adapter, NETMAP_RX_UNLOCK, i);
}
}
if (check_all && revents == 0) {
i = na->num_queues + 1; /* the global queue */
if (want_tx)
selrecord(td, &na->tx_rings[i].si);
if (want_rx)
selrecord(td, &na->rx_rings[i].si);
}
if (core_lock == LOCKED_CL)
na->nm_lock(adapter, NETMAP_CORE_UNLOCK, 0);
return (revents);
}
/*------- driver support routines ------*/
/*
* Initialize a ``netmap_adapter`` object created by driver on attach.
* We allocate a block of memory with room for a struct netmap_adapter
* plus two sets of N+2 struct netmap_kring (where N is the number
* of hardware rings):
* krings 0..N-1 are for the hardware queues.
* kring N is for the host stack queue
* kring N+1 is only used for the selinfo for all queues.
* Return 0 on success, ENOMEM otherwise.
*/
int
netmap_attach(struct netmap_adapter *na, int num_queues)
{
int n = num_queues + 2;
int size = sizeof(*na) + 2 * n * sizeof(struct netmap_kring);
void *buf;
struct ifnet *ifp = na->ifp;
if (ifp == NULL) {
D("ifp not set, giving up");
return EINVAL;
}
na->refcount = 0;
na->num_queues = num_queues;
buf = malloc(size, M_DEVBUF, M_NOWAIT | M_ZERO);
if (buf) {
WNA(ifp) = buf;
na->tx_rings = (void *)((char *)buf + sizeof(*na));
na->rx_rings = na->tx_rings + n;
bcopy(na, buf, sizeof(*na));
ifp->if_capabilities |= IFCAP_NETMAP;
}
D("%s for %s", buf ? "ok" : "failed", ifp->if_xname);
return (buf ? 0 : ENOMEM);
}
/*
* Free the allocated memory linked to the given ``netmap_adapter``
* object.
*/
void
netmap_detach(struct ifnet *ifp)
{
u_int i;
struct netmap_adapter *na = NA(ifp);
if (!na)
return;
for (i = 0; i < na->num_queues + 2; i++) {
knlist_destroy(&na->tx_rings[i].si.si_note);
knlist_destroy(&na->rx_rings[i].si.si_note);
}
bzero(na, sizeof(*na));
WNA(ifp) = NULL;
free(na, M_DEVBUF);
}
/*
* Intercept packets from the network stack and pass them
* to netmap as incoming packets on the 'software' ring.
* We are not locked when called.
*/
int
netmap_start(struct ifnet *ifp, struct mbuf *m)
{
struct netmap_adapter *na = NA(ifp);
struct netmap_kring *kring = &na->rx_rings[na->num_queues];
u_int i, len = m->m_pkthdr.len;
int error = EBUSY, lim = kring->nkr_num_slots - 1;
struct netmap_slot *slot;
if (netmap_verbose & NM_VERB_HOST)
D("%s packet %d len %d from the stack", ifp->if_xname,
kring->nr_hwcur + kring->nr_hwavail, len);
na->nm_lock(ifp->if_softc, NETMAP_CORE_LOCK, 0);
if (kring->nr_hwavail >= lim) {
D("stack ring %s full\n", ifp->if_xname);
goto done; /* no space */
}
if (len > na->buff_size) {
D("drop packet size %d > %d", len, na->buff_size);
goto done; /* too long for us */
}
/* compute the insert position */
i = kring->nr_hwcur + kring->nr_hwavail;
if (i > lim)
i -= lim + 1;
slot = &kring->ring->slot[i];
m_copydata(m, 0, len, NMB(slot));
slot->len = len;
kring->nr_hwavail++;
if (netmap_verbose & NM_VERB_HOST)
D("wake up host ring %s %d", na->ifp->if_xname, na->num_queues);
selwakeuppri(&kring->si, PI_NET);
error = 0;
done:
na->nm_lock(ifp->if_softc, NETMAP_CORE_UNLOCK, 0);
/* release the mbuf in either cases of success or failure. As an
* alternative, put the mbuf in a free list and free the list
* only when really necessary.
*/
m_freem(m);
return (error);
}
/*
* netmap_reset() is called by the driver routines when reinitializing
* a ring. The driver is in charge of locking to protect the kring.
* If netmap mode is not set just return NULL.
*/
struct netmap_slot *
netmap_reset(struct netmap_adapter *na, enum txrx tx, int n,
u_int new_cur)
{
struct netmap_kring *kring;
struct netmap_ring *ring;
int new_hwofs, lim;
if (na == NULL)
return NULL; /* no netmap support here */
if (!(na->ifp->if_capenable & IFCAP_NETMAP))
return NULL; /* nothing to reinitialize */
kring = tx == NR_TX ? na->tx_rings + n : na->rx_rings + n;
ring = kring->ring;
lim = kring->nkr_num_slots - 1;
if (tx == NR_TX)
new_hwofs = kring->nr_hwcur - new_cur;
else
new_hwofs = kring->nr_hwcur + kring->nr_hwavail - new_cur;
if (new_hwofs > lim)
new_hwofs -= lim + 1;
/* Alwayws set the new offset value and realign the ring. */
kring->nkr_hwofs = new_hwofs;
if (tx == NR_TX)
kring->nr_hwavail = kring->nkr_num_slots - 1;
D("new hwofs %d on %s %s[%d]",
kring->nkr_hwofs, na->ifp->if_xname,
tx == NR_TX ? "TX" : "RX", n);
/*
* We do the wakeup here, but the ring is not yet reconfigured.
* However, we are under lock so there are no races.
*/
selwakeuppri(&kring->si, PI_NET);
selwakeuppri(&kring[na->num_queues + 1 - n].si, PI_NET);
return kring->ring->slot;
}
/*------ netmap memory allocator -------*/
/*
* Request for a chunk of memory.
*
* Memory objects are arranged into a list, hence we need to walk this
* list until we find an object with the needed amount of data free.
* This sounds like a completely inefficient implementation, but given
* the fact that data allocation is done once, we can handle it
* flawlessly.
*
* Return NULL on failure.
*/
static void *
netmap_malloc(size_t size, __unused const char *msg)
{
struct netmap_mem_obj *mem_obj, *new_mem_obj;
void *ret = NULL;
NMA_LOCK();
TAILQ_FOREACH(mem_obj, &netmap_mem_d->nm_molist, nmo_next) {
if (mem_obj->nmo_used != 0 || mem_obj->nmo_size < size)
continue;
new_mem_obj = malloc(sizeof(struct netmap_mem_obj), M_NETMAP,
M_WAITOK | M_ZERO);
TAILQ_INSERT_BEFORE(mem_obj, new_mem_obj, nmo_next);
new_mem_obj->nmo_used = 1;
new_mem_obj->nmo_size = size;
new_mem_obj->nmo_data = mem_obj->nmo_data;
memset(new_mem_obj->nmo_data, 0, new_mem_obj->nmo_size);
mem_obj->nmo_size -= size;
mem_obj->nmo_data = (char *) mem_obj->nmo_data + size;
if (mem_obj->nmo_size == 0) {
TAILQ_REMOVE(&netmap_mem_d->nm_molist, mem_obj,
nmo_next);
free(mem_obj, M_NETMAP);
}
ret = new_mem_obj->nmo_data;
break;
}
NMA_UNLOCK();
ND("%s: %d bytes at %p", msg, size, ret);
return (ret);
}
/*
* Return the memory to the allocator.
*
* While freeing a memory object, we try to merge adjacent chunks in
* order to reduce memory fragmentation.
*/
static void
netmap_free(void *addr, const char *msg)
{
size_t size;
struct netmap_mem_obj *cur, *prev, *next;
if (addr == NULL) {
D("NULL addr for %s", msg);
return;
}
NMA_LOCK();
TAILQ_FOREACH(cur, &netmap_mem_d->nm_molist, nmo_next) {
if (cur->nmo_data == addr && cur->nmo_used)
break;
}
if (cur == NULL) {
NMA_UNLOCK();
D("invalid addr %s %p", msg, addr);
return;
}
size = cur->nmo_size;
cur->nmo_used = 0;
/* merge current chunk of memory with the previous one,
if present. */
prev = TAILQ_PREV(cur, netmap_mem_obj_h, nmo_next);
if (prev && prev->nmo_used == 0) {
TAILQ_REMOVE(&netmap_mem_d->nm_molist, cur, nmo_next);
prev->nmo_size += cur->nmo_size;
free(cur, M_NETMAP);
cur = prev;
}
/* merge with the next one */
next = TAILQ_NEXT(cur, nmo_next);
if (next && next->nmo_used == 0) {
TAILQ_REMOVE(&netmap_mem_d->nm_molist, next, nmo_next);
cur->nmo_size += next->nmo_size;
free(next, M_NETMAP);
}
NMA_UNLOCK();
ND("freed %s %d bytes at %p", msg, size, addr);
}
/*
* Initialize the memory allocator.
*
* Create the descriptor for the memory , allocate the pool of memory
* and initialize the list of memory objects with a single chunk
* containing the whole pre-allocated memory marked as free.
*
* Start with a large size, then halve as needed if we fail to
* allocate the block. While halving, always add one extra page
* because buffers 0 and 1 are used for special purposes.
* Return 0 on success, errno otherwise.
*/
static int
netmap_memory_init(void)
{
struct netmap_mem_obj *mem_obj;
void *buf = NULL;
int i, n, sz = NETMAP_MEMORY_SIZE;
int extra_sz = 0; // space for rings and two spare buffers
for (; sz >= 1<<20; sz >>=1) {
extra_sz = sz/200;
extra_sz = (extra_sz + 2*PAGE_SIZE - 1) & ~(PAGE_SIZE-1);
buf = contigmalloc(sz + extra_sz,
M_NETMAP,
M_WAITOK | M_ZERO,
0, /* low address */
-1UL, /* high address */
PAGE_SIZE, /* alignment */
0 /* boundary */
);
if (buf)
break;
}
if (buf == NULL)
return (ENOMEM);
sz += extra_sz;
netmap_mem_d = malloc(sizeof(struct netmap_mem_d), M_NETMAP,
M_WAITOK | M_ZERO);
mtx_init(&netmap_mem_d->nm_mtx, "netmap memory allocator lock", NULL,
MTX_DEF);
TAILQ_INIT(&netmap_mem_d->nm_molist);
netmap_mem_d->nm_buffer = buf;
netmap_mem_d->nm_totalsize = sz;
/*
* A buffer takes 2k, a slot takes 8 bytes + ring overhead,
* so the ratio is 200:1. In other words, we can use 1/200 of
* the memory for the rings, and the rest for the buffers,
* and be sure we never run out.
*/
netmap_mem_d->nm_size = sz/200;
netmap_mem_d->nm_buf_start =
(netmap_mem_d->nm_size + PAGE_SIZE - 1) & ~(PAGE_SIZE-1);
netmap_mem_d->nm_buf_len = sz - netmap_mem_d->nm_buf_start;
nm_buf_pool.base = netmap_mem_d->nm_buffer;
nm_buf_pool.base += netmap_mem_d->nm_buf_start;
netmap_buffer_base = nm_buf_pool.base;
D("netmap_buffer_base %p (offset %d)",
netmap_buffer_base, (int)netmap_mem_d->nm_buf_start);
/* number of buffers, they all start as free */
netmap_total_buffers = nm_buf_pool.total_buffers =
netmap_mem_d->nm_buf_len / NETMAP_BUF_SIZE;
nm_buf_pool.bufsize = NETMAP_BUF_SIZE;
D("Have %d MB, use %dKB for rings, %d buffers at %p",
(sz >> 20), (int)(netmap_mem_d->nm_size >> 10),
nm_buf_pool.total_buffers, nm_buf_pool.base);
/* allocate and initialize the bitmap. Entry 0 is considered
* always busy (used as default when there are no buffers left).
*/
n = (nm_buf_pool.total_buffers + 31) / 32;
nm_buf_pool.bitmap = malloc(sizeof(uint32_t) * n, M_NETMAP,
M_WAITOK | M_ZERO);
nm_buf_pool.bitmap[0] = ~3; /* slot 0 and 1 always busy */
for (i = 1; i < n; i++)
nm_buf_pool.bitmap[i] = ~0;
nm_buf_pool.free = nm_buf_pool.total_buffers - 2;
mem_obj = malloc(sizeof(struct netmap_mem_obj), M_NETMAP,
M_WAITOK | M_ZERO);
TAILQ_INSERT_HEAD(&netmap_mem_d->nm_molist, mem_obj, nmo_next);
mem_obj->nmo_used = 0;
mem_obj->nmo_size = netmap_mem_d->nm_size;
mem_obj->nmo_data = netmap_mem_d->nm_buffer;
return (0);
}
/*
* Finalize the memory allocator.
*
* Free all the memory objects contained inside the list, and deallocate
* the pool of memory; finally free the memory allocator descriptor.
*/
static void
netmap_memory_fini(void)
{
struct netmap_mem_obj *mem_obj;
while (!TAILQ_EMPTY(&netmap_mem_d->nm_molist)) {
mem_obj = TAILQ_FIRST(&netmap_mem_d->nm_molist);
TAILQ_REMOVE(&netmap_mem_d->nm_molist, mem_obj, nmo_next);
if (mem_obj->nmo_used == 1) {
printf("netmap: leaked %d bytes at %p\n",
(int)mem_obj->nmo_size,
mem_obj->nmo_data);
}
free(mem_obj, M_NETMAP);
}
contigfree(netmap_mem_d->nm_buffer, netmap_mem_d->nm_totalsize, M_NETMAP);
// XXX mutex_destroy(nm_mtx);
free(netmap_mem_d, M_NETMAP);
}
/*
* Module loader.
*
* Create the /dev/netmap device and initialize all global
* variables.
*
* Return 0 on success, errno on failure.
*/
static int
netmap_init(void)
{
int error;
error = netmap_memory_init();
if (error != 0) {
printf("netmap: unable to initialize the memory allocator.");
return (error);
}
printf("netmap: loaded module with %d Mbytes\n",
(int)(netmap_mem_d->nm_totalsize >> 20));
netmap_dev = make_dev(&netmap_cdevsw, 0, UID_ROOT, GID_WHEEL, 0660,
"netmap");
return (0);
}
/*
* Module unloader.
*
* Free all the memory, and destroy the ``/dev/netmap`` device.
*/
static void
netmap_fini(void)
{
destroy_dev(netmap_dev);
netmap_memory_fini();
printf("netmap: unloaded module.\n");
}
/*
* Kernel entry point.
*
* Initialize/finalize the module and return.
*
* Return 0 on success, errno on failure.
*/
static int
netmap_loader(__unused struct module *module, int event, __unused void *arg)
{
int error = 0;
switch (event) {
case MOD_LOAD:
error = netmap_init();
break;
case MOD_UNLOAD:
netmap_fini();
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
DEV_MODULE(netmap, netmap_loader, NULL);
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