netfront.c revision 291239
1/*-
2 * Copyright (c) 2004-2006 Kip Macy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/10/sys/dev/xen/netfront/netfront.c 291239 2015-11-24 08:41:27Z royger $");
29
30#include "opt_inet.h"
31#include "opt_inet6.h"
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/sockio.h>
36#include <sys/mbuf.h>
37#include <sys/malloc.h>
38#include <sys/module.h>
39#include <sys/kernel.h>
40#include <sys/socket.h>
41#include <sys/sysctl.h>
42#include <sys/queue.h>
43#include <sys/lock.h>
44#include <sys/sx.h>
45#include <sys/limits.h>
46
47#include <net/if.h>
48#include <net/if_arp.h>
49#include <net/ethernet.h>
50#include <net/if_dl.h>
51#include <net/if_media.h>
52
53#include <net/bpf.h>
54
55#include <net/if_types.h>
56#include <net/if.h>
57
58#include <netinet/in_systm.h>
59#include <netinet/in.h>
60#include <netinet/ip.h>
61#include <netinet/if_ether.h>
62#if __FreeBSD_version >= 700000
63#include <netinet/tcp.h>
64#include <netinet/tcp_lro.h>
65#endif
66
67#include <vm/vm.h>
68#include <vm/pmap.h>
69
70#include <machine/clock.h>      /* for DELAY */
71#include <machine/bus.h>
72#include <machine/resource.h>
73#include <machine/frame.h>
74#include <machine/vmparam.h>
75
76#include <sys/bus.h>
77#include <sys/rman.h>
78
79#include <machine/intr_machdep.h>
80
81#include <xen/xen-os.h>
82#include <xen/hypervisor.h>
83#include <xen/xen_intr.h>
84#include <xen/gnttab.h>
85#include <xen/interface/memory.h>
86#include <xen/interface/io/netif.h>
87#include <xen/xenbus/xenbusvar.h>
88
89#include <machine/xen/xenvar.h>
90
91#include <dev/xen/netfront/mbufq.h>
92
93#include "xenbus_if.h"
94
95/* Features supported by all backends.  TSO and LRO can be negotiated */
96#define XN_CSUM_FEATURES	(CSUM_TCP | CSUM_UDP)
97
98#define NET_TX_RING_SIZE __RING_SIZE((netif_tx_sring_t *)0, PAGE_SIZE)
99#define NET_RX_RING_SIZE __RING_SIZE((netif_rx_sring_t *)0, PAGE_SIZE)
100
101#if __FreeBSD_version >= 700000
102/*
103 * Should the driver do LRO on the RX end
104 *  this can be toggled on the fly, but the
105 *  interface must be reset (down/up) for it
106 *  to take effect.
107 */
108static int xn_enable_lro = 1;
109TUNABLE_INT("hw.xn.enable_lro", &xn_enable_lro);
110#else
111
112#define IFCAP_TSO4	0
113#define CSUM_TSO	0
114
115#endif
116
117#ifdef CONFIG_XEN
118static int MODPARM_rx_copy = 0;
119module_param_named(rx_copy, MODPARM_rx_copy, bool, 0);
120MODULE_PARM_DESC(rx_copy, "Copy packets from network card (rather than flip)");
121static int MODPARM_rx_flip = 0;
122module_param_named(rx_flip, MODPARM_rx_flip, bool, 0);
123MODULE_PARM_DESC(rx_flip, "Flip packets from network card (rather than copy)");
124#else
125static const int MODPARM_rx_copy = 1;
126static const int MODPARM_rx_flip = 0;
127#endif
128
129/**
130 * \brief The maximum allowed data fragments in a single transmit
131 *        request.
132 *
133 * This limit is imposed by the backend driver.  We assume here that
134 * we are dealing with a Linux driver domain and have set our limit
135 * to mirror the Linux MAX_SKB_FRAGS constant.
136 */
137#define	MAX_TX_REQ_FRAGS (65536 / PAGE_SIZE + 2)
138
139#define RX_COPY_THRESHOLD 256
140
141#define net_ratelimit() 0
142
143struct netfront_info;
144struct netfront_rx_info;
145
146static void xn_txeof(struct netfront_info *);
147static void xn_rxeof(struct netfront_info *);
148static void network_alloc_rx_buffers(struct netfront_info *);
149
150static void xn_tick_locked(struct netfront_info *);
151static void xn_tick(void *);
152
153static void xn_intr(void *);
154static inline int xn_count_frags(struct mbuf *m);
155static int  xn_assemble_tx_request(struct netfront_info *sc,
156				   struct mbuf *m_head);
157static void xn_start_locked(struct ifnet *);
158static void xn_start(struct ifnet *);
159static int  xn_ioctl(struct ifnet *, u_long, caddr_t);
160static void xn_ifinit_locked(struct netfront_info *);
161static void xn_ifinit(void *);
162static void xn_stop(struct netfront_info *);
163static void xn_query_features(struct netfront_info *np);
164static int  xn_configure_features(struct netfront_info *np);
165#ifdef notyet
166static void xn_watchdog(struct ifnet *);
167#endif
168
169#ifdef notyet
170static void netfront_closing(device_t dev);
171#endif
172static void netif_free(struct netfront_info *info);
173static int netfront_detach(device_t dev);
174
175static int talk_to_backend(device_t dev, struct netfront_info *info);
176static int create_netdev(device_t dev);
177static void netif_disconnect_backend(struct netfront_info *info);
178static int setup_device(device_t dev, struct netfront_info *info);
179static void free_ring(int *ref, void *ring_ptr_ref);
180
181static int  xn_ifmedia_upd(struct ifnet *ifp);
182static void xn_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr);
183
184/* Xenolinux helper functions */
185int network_connect(struct netfront_info *);
186
187static void xn_free_rx_ring(struct netfront_info *);
188
189static void xn_free_tx_ring(struct netfront_info *);
190
191static int xennet_get_responses(struct netfront_info *np,
192	struct netfront_rx_info *rinfo, RING_IDX rp, RING_IDX *cons,
193	struct mbuf **list, int *pages_flipped_p);
194
195#define virt_to_mfn(x) (vtomach(x) >> PAGE_SHIFT)
196
197#define INVALID_P2M_ENTRY (~0UL)
198
199/*
200 * Mbuf pointers. We need these to keep track of the virtual addresses
201 * of our mbuf chains since we can only convert from virtual to physical,
202 * not the other way around.  The size must track the free index arrays.
203 */
204struct xn_chain_data {
205	struct mbuf    *xn_tx_chain[NET_TX_RING_SIZE+1];
206	int		xn_tx_chain_cnt;
207	struct mbuf    *xn_rx_chain[NET_RX_RING_SIZE+1];
208};
209
210struct net_device_stats
211{
212	u_long	rx_packets;		/* total packets received	*/
213	u_long	tx_packets;		/* total packets transmitted	*/
214	u_long	rx_bytes;		/* total bytes received 	*/
215	u_long	tx_bytes;		/* total bytes transmitted	*/
216	u_long	rx_errors;		/* bad packets received		*/
217	u_long	tx_errors;		/* packet transmit problems	*/
218	u_long	rx_dropped;		/* no space in linux buffers	*/
219	u_long	tx_dropped;		/* no space available in linux	*/
220	u_long	multicast;		/* multicast packets received	*/
221	u_long	collisions;
222
223	/* detailed rx_errors: */
224	u_long	rx_length_errors;
225	u_long	rx_over_errors;		/* receiver ring buff overflow	*/
226	u_long	rx_crc_errors;		/* recved pkt with crc error	*/
227	u_long	rx_frame_errors;	/* recv'd frame alignment error */
228	u_long	rx_fifo_errors;		/* recv'r fifo overrun		*/
229	u_long	rx_missed_errors;	/* receiver missed packet	*/
230
231	/* detailed tx_errors */
232	u_long	tx_aborted_errors;
233	u_long	tx_carrier_errors;
234	u_long	tx_fifo_errors;
235	u_long	tx_heartbeat_errors;
236	u_long	tx_window_errors;
237
238	/* for cslip etc */
239	u_long	rx_compressed;
240	u_long	tx_compressed;
241};
242
243struct netfront_info {
244	struct ifnet *xn_ifp;
245#if __FreeBSD_version >= 700000
246	struct lro_ctrl xn_lro;
247#endif
248
249	struct net_device_stats stats;
250	u_int tx_full;
251
252	netif_tx_front_ring_t tx;
253	netif_rx_front_ring_t rx;
254
255	struct mtx   tx_lock;
256	struct mtx   rx_lock;
257	struct mtx   sc_lock;
258
259	xen_intr_handle_t xen_intr_handle;
260	u_int copying_receiver;
261	u_int carrier;
262	u_int maxfrags;
263
264	/* Receive-ring batched refills. */
265#define RX_MIN_TARGET 32
266#define RX_MAX_TARGET NET_RX_RING_SIZE
267	int rx_min_target;
268	int rx_max_target;
269	int rx_target;
270
271	grant_ref_t gref_tx_head;
272	grant_ref_t grant_tx_ref[NET_TX_RING_SIZE + 1];
273	grant_ref_t gref_rx_head;
274	grant_ref_t grant_rx_ref[NET_TX_RING_SIZE + 1];
275
276	device_t		xbdev;
277	int			tx_ring_ref;
278	int			rx_ring_ref;
279	uint8_t			mac[ETHER_ADDR_LEN];
280	struct xn_chain_data	xn_cdata;	/* mbufs */
281	struct mbuf_head	xn_rx_batch;	/* head of the batch queue */
282
283	int			xn_if_flags;
284	struct callout	        xn_stat_ch;
285
286	u_long			rx_pfn_array[NET_RX_RING_SIZE];
287	multicall_entry_t	rx_mcl[NET_RX_RING_SIZE+1];
288	mmu_update_t		rx_mmu[NET_RX_RING_SIZE];
289	struct ifmedia		sc_media;
290
291	bool			xn_resume;
292};
293
294#define rx_mbufs xn_cdata.xn_rx_chain
295#define tx_mbufs xn_cdata.xn_tx_chain
296
297#define XN_LOCK_INIT(_sc, _name) \
298        mtx_init(&(_sc)->tx_lock, #_name"_tx", "network transmit lock", MTX_DEF); \
299        mtx_init(&(_sc)->rx_lock, #_name"_rx", "network receive lock", MTX_DEF);  \
300        mtx_init(&(_sc)->sc_lock, #_name"_sc", "netfront softc lock", MTX_DEF)
301
302#define XN_RX_LOCK(_sc)           mtx_lock(&(_sc)->rx_lock)
303#define XN_RX_UNLOCK(_sc)         mtx_unlock(&(_sc)->rx_lock)
304
305#define XN_TX_LOCK(_sc)           mtx_lock(&(_sc)->tx_lock)
306#define XN_TX_UNLOCK(_sc)         mtx_unlock(&(_sc)->tx_lock)
307
308#define XN_LOCK(_sc)           mtx_lock(&(_sc)->sc_lock);
309#define XN_UNLOCK(_sc)         mtx_unlock(&(_sc)->sc_lock);
310
311#define XN_LOCK_ASSERT(_sc)    mtx_assert(&(_sc)->sc_lock, MA_OWNED);
312#define XN_RX_LOCK_ASSERT(_sc)    mtx_assert(&(_sc)->rx_lock, MA_OWNED);
313#define XN_TX_LOCK_ASSERT(_sc)    mtx_assert(&(_sc)->tx_lock, MA_OWNED);
314#define XN_LOCK_DESTROY(_sc)   mtx_destroy(&(_sc)->rx_lock); \
315                               mtx_destroy(&(_sc)->tx_lock); \
316                               mtx_destroy(&(_sc)->sc_lock);
317
318struct netfront_rx_info {
319	struct netif_rx_response rx;
320	struct netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
321};
322
323#define netfront_carrier_on(netif)	((netif)->carrier = 1)
324#define netfront_carrier_off(netif)	((netif)->carrier = 0)
325#define netfront_carrier_ok(netif)	((netif)->carrier)
326
327/* Access macros for acquiring freeing slots in xn_free_{tx,rx}_idxs[]. */
328
329static inline void
330add_id_to_freelist(struct mbuf **list, uintptr_t id)
331{
332	KASSERT(id != 0,
333		("%s: the head item (0) must always be free.", __func__));
334	list[id] = list[0];
335	list[0]  = (struct mbuf *)id;
336}
337
338static inline unsigned short
339get_id_from_freelist(struct mbuf **list)
340{
341	uintptr_t id;
342
343	id = (uintptr_t)list[0];
344	KASSERT(id != 0,
345		("%s: the head item (0) must always remain free.", __func__));
346	list[0] = list[id];
347	return (id);
348}
349
350static inline int
351xennet_rxidx(RING_IDX idx)
352{
353	return idx & (NET_RX_RING_SIZE - 1);
354}
355
356static inline struct mbuf *
357xennet_get_rx_mbuf(struct netfront_info *np, RING_IDX ri)
358{
359	int i = xennet_rxidx(ri);
360	struct mbuf *m;
361
362	m = np->rx_mbufs[i];
363	np->rx_mbufs[i] = NULL;
364	return (m);
365}
366
367static inline grant_ref_t
368xennet_get_rx_ref(struct netfront_info *np, RING_IDX ri)
369{
370	int i = xennet_rxidx(ri);
371	grant_ref_t ref = np->grant_rx_ref[i];
372	KASSERT(ref != GRANT_REF_INVALID, ("Invalid grant reference!\n"));
373	np->grant_rx_ref[i] = GRANT_REF_INVALID;
374	return ref;
375}
376
377#define IPRINTK(fmt, args...) \
378    printf("[XEN] " fmt, ##args)
379#ifdef INVARIANTS
380#define WPRINTK(fmt, args...) \
381    printf("[XEN] " fmt, ##args)
382#else
383#define WPRINTK(fmt, args...)
384#endif
385#ifdef DEBUG
386#define DPRINTK(fmt, args...) \
387    printf("[XEN] %s: " fmt, __func__, ##args)
388#else
389#define DPRINTK(fmt, args...)
390#endif
391
392/**
393 * Read the 'mac' node at the given device's node in the store, and parse that
394 * as colon-separated octets, placing result the given mac array.  mac must be
395 * a preallocated array of length ETH_ALEN (as declared in linux/if_ether.h).
396 * Return 0 on success, or errno on error.
397 */
398static int
399xen_net_read_mac(device_t dev, uint8_t mac[])
400{
401	int error, i;
402	char *s, *e, *macstr;
403	const char *path;
404
405	path = xenbus_get_node(dev);
406	error = xs_read(XST_NIL, path, "mac", NULL, (void **) &macstr);
407	if (error == ENOENT) {
408		/*
409		 * Deal with missing mac XenStore nodes on devices with
410		 * HVM emulation (the 'ioemu' configuration attribute)
411		 * enabled.
412		 *
413		 * The HVM emulator may execute in a stub device model
414		 * domain which lacks the permission, only given to Dom0,
415		 * to update the guest's XenStore tree.  For this reason,
416		 * the HVM emulator doesn't even attempt to write the
417		 * front-side mac node, even when operating in Dom0.
418		 * However, there should always be a mac listed in the
419		 * backend tree.  Fallback to this version if our query
420		 * of the front side XenStore location doesn't find
421		 * anything.
422		 */
423		path = xenbus_get_otherend_path(dev);
424		error = xs_read(XST_NIL, path, "mac", NULL, (void **) &macstr);
425	}
426	if (error != 0) {
427		xenbus_dev_fatal(dev, error, "parsing %s/mac", path);
428		return (error);
429	}
430
431	s = macstr;
432	for (i = 0; i < ETHER_ADDR_LEN; i++) {
433		mac[i] = strtoul(s, &e, 16);
434		if (s == e || (e[0] != ':' && e[0] != 0)) {
435			free(macstr, M_XENBUS);
436			return (ENOENT);
437		}
438		s = &e[1];
439	}
440	free(macstr, M_XENBUS);
441	return (0);
442}
443
444/**
445 * Entry point to this code when a new device is created.  Allocate the basic
446 * structures and the ring buffers for communication with the backend, and
447 * inform the backend of the appropriate details for those.  Switch to
448 * Connected state.
449 */
450static int
451netfront_probe(device_t dev)
452{
453
454#ifdef XENHVM
455	if (xen_disable_pv_nics != 0)
456		return (ENXIO);
457#endif
458
459	if (!strcmp(xenbus_get_type(dev), "vif")) {
460		device_set_desc(dev, "Virtual Network Interface");
461		return (0);
462	}
463
464	return (ENXIO);
465}
466
467static int
468netfront_attach(device_t dev)
469{
470	int err;
471
472	err = create_netdev(dev);
473	if (err) {
474		xenbus_dev_fatal(dev, err, "creating netdev");
475		return (err);
476	}
477
478#if __FreeBSD_version >= 700000
479	SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
480	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
481	    OID_AUTO, "enable_lro", CTLFLAG_RW,
482	    &xn_enable_lro, 0, "Large Receive Offload");
483#endif
484
485	return (0);
486}
487
488static int
489netfront_suspend(device_t dev)
490{
491	struct netfront_info *info = device_get_softc(dev);
492
493	XN_RX_LOCK(info);
494	XN_TX_LOCK(info);
495	netfront_carrier_off(info);
496	XN_TX_UNLOCK(info);
497	XN_RX_UNLOCK(info);
498	return (0);
499}
500
501/**
502 * We are reconnecting to the backend, due to a suspend/resume, or a backend
503 * driver restart.  We tear down our netif structure and recreate it, but
504 * leave the device-layer structures intact so that this is transparent to the
505 * rest of the kernel.
506 */
507static int
508netfront_resume(device_t dev)
509{
510	struct netfront_info *info = device_get_softc(dev);
511
512	info->xn_resume = true;
513	netif_disconnect_backend(info);
514	return (0);
515}
516
517/* Common code used when first setting up, and when resuming. */
518static int
519talk_to_backend(device_t dev, struct netfront_info *info)
520{
521	const char *message;
522	struct xs_transaction xst;
523	const char *node = xenbus_get_node(dev);
524	int err;
525
526	err = xen_net_read_mac(dev, info->mac);
527	if (err) {
528		xenbus_dev_fatal(dev, err, "parsing %s/mac", node);
529		goto out;
530	}
531
532	/* Create shared ring, alloc event channel. */
533	err = setup_device(dev, info);
534	if (err)
535		goto out;
536
537 again:
538	err = xs_transaction_start(&xst);
539	if (err) {
540		xenbus_dev_fatal(dev, err, "starting transaction");
541		goto destroy_ring;
542	}
543	err = xs_printf(xst, node, "tx-ring-ref","%u",
544			info->tx_ring_ref);
545	if (err) {
546		message = "writing tx ring-ref";
547		goto abort_transaction;
548	}
549	err = xs_printf(xst, node, "rx-ring-ref","%u",
550			info->rx_ring_ref);
551	if (err) {
552		message = "writing rx ring-ref";
553		goto abort_transaction;
554	}
555	err = xs_printf(xst, node,
556			"event-channel", "%u",
557			xen_intr_port(info->xen_intr_handle));
558	if (err) {
559		message = "writing event-channel";
560		goto abort_transaction;
561	}
562	err = xs_printf(xst, node, "request-rx-copy", "%u",
563			info->copying_receiver);
564	if (err) {
565		message = "writing request-rx-copy";
566		goto abort_transaction;
567	}
568	err = xs_printf(xst, node, "feature-rx-notify", "%d", 1);
569	if (err) {
570		message = "writing feature-rx-notify";
571		goto abort_transaction;
572	}
573	err = xs_printf(xst, node, "feature-sg", "%d", 1);
574	if (err) {
575		message = "writing feature-sg";
576		goto abort_transaction;
577	}
578#if __FreeBSD_version >= 700000
579	err = xs_printf(xst, node, "feature-gso-tcpv4", "%d", 1);
580	if (err) {
581		message = "writing feature-gso-tcpv4";
582		goto abort_transaction;
583	}
584#endif
585
586	err = xs_transaction_end(xst, 0);
587	if (err) {
588		if (err == EAGAIN)
589			goto again;
590		xenbus_dev_fatal(dev, err, "completing transaction");
591		goto destroy_ring;
592	}
593
594	return 0;
595
596 abort_transaction:
597	xs_transaction_end(xst, 1);
598	xenbus_dev_fatal(dev, err, "%s", message);
599 destroy_ring:
600	netif_free(info);
601 out:
602	return err;
603}
604
605static int
606setup_device(device_t dev, struct netfront_info *info)
607{
608	netif_tx_sring_t *txs;
609	netif_rx_sring_t *rxs;
610	int error;
611	struct ifnet *ifp;
612
613	ifp = info->xn_ifp;
614
615	info->tx_ring_ref = GRANT_REF_INVALID;
616	info->rx_ring_ref = GRANT_REF_INVALID;
617	info->rx.sring = NULL;
618	info->tx.sring = NULL;
619
620	txs = (netif_tx_sring_t *)malloc(PAGE_SIZE, M_DEVBUF, M_NOWAIT|M_ZERO);
621	if (!txs) {
622		error = ENOMEM;
623		xenbus_dev_fatal(dev, error, "allocating tx ring page");
624		goto fail;
625	}
626	SHARED_RING_INIT(txs);
627	FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
628	error = xenbus_grant_ring(dev, virt_to_mfn(txs), &info->tx_ring_ref);
629	if (error)
630		goto fail;
631
632	rxs = (netif_rx_sring_t *)malloc(PAGE_SIZE, M_DEVBUF, M_NOWAIT|M_ZERO);
633	if (!rxs) {
634		error = ENOMEM;
635		xenbus_dev_fatal(dev, error, "allocating rx ring page");
636		goto fail;
637	}
638	SHARED_RING_INIT(rxs);
639	FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
640
641	error = xenbus_grant_ring(dev, virt_to_mfn(rxs), &info->rx_ring_ref);
642	if (error)
643		goto fail;
644
645	error = xen_intr_alloc_and_bind_local_port(dev,
646	    xenbus_get_otherend_id(dev), /*filter*/NULL, xn_intr, info,
647	    INTR_TYPE_NET | INTR_MPSAFE | INTR_ENTROPY, &info->xen_intr_handle);
648
649	if (error) {
650		xenbus_dev_fatal(dev, error,
651				 "xen_intr_alloc_and_bind_local_port failed");
652		goto fail;
653	}
654
655	return (0);
656
657 fail:
658	netif_free(info);
659	return (error);
660}
661
662#ifdef INET
663/**
664 * If this interface has an ipv4 address, send an arp for it. This
665 * helps to get the network going again after migrating hosts.
666 */
667static void
668netfront_send_fake_arp(device_t dev, struct netfront_info *info)
669{
670	struct ifnet *ifp;
671	struct ifaddr *ifa;
672
673	ifp = info->xn_ifp;
674	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
675		if (ifa->ifa_addr->sa_family == AF_INET) {
676			arp_ifinit(ifp, ifa);
677		}
678	}
679}
680#endif
681
682/**
683 * Callback received when the backend's state changes.
684 */
685static void
686netfront_backend_changed(device_t dev, XenbusState newstate)
687{
688	struct netfront_info *sc = device_get_softc(dev);
689
690	DPRINTK("newstate=%d\n", newstate);
691
692	switch (newstate) {
693	case XenbusStateInitialising:
694	case XenbusStateInitialised:
695	case XenbusStateUnknown:
696	case XenbusStateClosed:
697	case XenbusStateReconfigured:
698	case XenbusStateReconfiguring:
699		break;
700	case XenbusStateInitWait:
701		if (xenbus_get_state(dev) != XenbusStateInitialising)
702			break;
703		if (network_connect(sc) != 0)
704			break;
705		xenbus_set_state(dev, XenbusStateConnected);
706		break;
707	case XenbusStateClosing:
708		xenbus_set_state(dev, XenbusStateClosed);
709		break;
710	case XenbusStateConnected:
711#ifdef INET
712		netfront_send_fake_arp(dev, sc);
713#endif
714		break;
715	}
716}
717
718static void
719xn_free_rx_ring(struct netfront_info *sc)
720{
721#if 0
722	int i;
723
724	for (i = 0; i < NET_RX_RING_SIZE; i++) {
725		if (sc->xn_cdata.rx_mbufs[i] != NULL) {
726			m_freem(sc->rx_mbufs[i]);
727			sc->rx_mbufs[i] = NULL;
728		}
729	}
730
731	sc->rx.rsp_cons = 0;
732	sc->xn_rx_if->req_prod = 0;
733	sc->xn_rx_if->event = sc->rx.rsp_cons ;
734#endif
735}
736
737static void
738xn_free_tx_ring(struct netfront_info *sc)
739{
740#if 0
741	int i;
742
743	for (i = 0; i < NET_TX_RING_SIZE; i++) {
744		if (sc->tx_mbufs[i] != NULL) {
745			m_freem(sc->tx_mbufs[i]);
746			sc->xn_cdata.xn_tx_chain[i] = NULL;
747		}
748	}
749
750	return;
751#endif
752}
753
754/**
755 * \brief Verify that there is sufficient space in the Tx ring
756 *        buffer for a maximally sized request to be enqueued.
757 *
758 * A transmit request requires a transmit descriptor for each packet
759 * fragment, plus up to 2 entries for "options" (e.g. TSO).
760 */
761static inline int
762xn_tx_slot_available(struct netfront_info *np)
763{
764	return (RING_FREE_REQUESTS(&np->tx) > (MAX_TX_REQ_FRAGS + 2));
765}
766
767static void
768netif_release_tx_bufs(struct netfront_info *np)
769{
770	int i;
771
772	for (i = 1; i <= NET_TX_RING_SIZE; i++) {
773		struct mbuf *m;
774
775		m = np->tx_mbufs[i];
776
777		/*
778		 * We assume that no kernel addresses are
779		 * less than NET_TX_RING_SIZE.  Any entry
780		 * in the table that is below this number
781		 * must be an index from free-list tracking.
782		 */
783		if (((uintptr_t)m) <= NET_TX_RING_SIZE)
784			continue;
785		gnttab_end_foreign_access_ref(np->grant_tx_ref[i]);
786		gnttab_release_grant_reference(&np->gref_tx_head,
787		    np->grant_tx_ref[i]);
788		np->grant_tx_ref[i] = GRANT_REF_INVALID;
789		add_id_to_freelist(np->tx_mbufs, i);
790		np->xn_cdata.xn_tx_chain_cnt--;
791		if (np->xn_cdata.xn_tx_chain_cnt < 0) {
792			panic("%s: tx_chain_cnt must be >= 0", __func__);
793		}
794		m_free(m);
795	}
796}
797
798static void
799network_alloc_rx_buffers(struct netfront_info *sc)
800{
801	int otherend_id = xenbus_get_otherend_id(sc->xbdev);
802	unsigned short id;
803	struct mbuf *m_new;
804	int i, batch_target, notify;
805	RING_IDX req_prod;
806	struct xen_memory_reservation reservation;
807	grant_ref_t ref;
808	int nr_flips;
809	netif_rx_request_t *req;
810	vm_offset_t vaddr;
811	u_long pfn;
812
813	req_prod = sc->rx.req_prod_pvt;
814
815	if (__predict_false(sc->carrier == 0))
816		return;
817
818	/*
819	 * Allocate mbufs greedily, even though we batch updates to the
820	 * receive ring. This creates a less bursty demand on the memory
821	 * allocator, and so should reduce the chance of failed allocation
822	 * requests both for ourself and for other kernel subsystems.
823	 *
824	 * Here we attempt to maintain rx_target buffers in flight, counting
825	 * buffers that we have yet to process in the receive ring.
826	 */
827	batch_target = sc->rx_target - (req_prod - sc->rx.rsp_cons);
828	for (i = mbufq_len(&sc->xn_rx_batch); i < batch_target; i++) {
829		MGETHDR(m_new, M_NOWAIT, MT_DATA);
830		if (m_new == NULL) {
831			printf("%s: MGETHDR failed\n", __func__);
832			goto no_mbuf;
833		}
834
835		m_cljget(m_new, M_NOWAIT, MJUMPAGESIZE);
836		if ((m_new->m_flags & M_EXT) == 0) {
837			printf("%s: m_cljget failed\n", __func__);
838			m_freem(m_new);
839
840no_mbuf:
841			if (i != 0)
842				goto refill;
843			/*
844			 * XXX set timer
845			 */
846			break;
847		}
848		m_new->m_len = m_new->m_pkthdr.len = MJUMPAGESIZE;
849
850		/* queue the mbufs allocated */
851		mbufq_tail(&sc->xn_rx_batch, m_new);
852	}
853
854	/*
855	 * If we've allocated at least half of our target number of entries,
856	 * submit them to the backend - we have enough to make the overhead
857	 * of submission worthwhile.  Otherwise wait for more mbufs and
858	 * request entries to become available.
859	 */
860	if (i < (sc->rx_target/2)) {
861		if (req_prod >sc->rx.sring->req_prod)
862			goto push;
863		return;
864	}
865
866	/*
867	 * Double floating fill target if we risked having the backend
868	 * run out of empty buffers for receive traffic.  We define "running
869	 * low" as having less than a fourth of our target buffers free
870	 * at the time we refilled the queue.
871	 */
872	if ((req_prod - sc->rx.sring->rsp_prod) < (sc->rx_target / 4)) {
873		sc->rx_target *= 2;
874		if (sc->rx_target > sc->rx_max_target)
875			sc->rx_target = sc->rx_max_target;
876	}
877
878refill:
879	for (nr_flips = i = 0; ; i++) {
880		if ((m_new = mbufq_dequeue(&sc->xn_rx_batch)) == NULL)
881			break;
882
883		m_new->m_ext.ext_arg1 = (vm_paddr_t *)(uintptr_t)(
884				vtophys(m_new->m_ext.ext_buf) >> PAGE_SHIFT);
885
886		id = xennet_rxidx(req_prod + i);
887
888		KASSERT(sc->rx_mbufs[id] == NULL, ("non-NULL xm_rx_chain"));
889		sc->rx_mbufs[id] = m_new;
890
891		ref = gnttab_claim_grant_reference(&sc->gref_rx_head);
892		KASSERT(ref != GNTTAB_LIST_END,
893			("reserved grant references exhuasted"));
894		sc->grant_rx_ref[id] = ref;
895
896		vaddr = mtod(m_new, vm_offset_t);
897		pfn = vtophys(vaddr) >> PAGE_SHIFT;
898		req = RING_GET_REQUEST(&sc->rx, req_prod + i);
899
900		if (sc->copying_receiver == 0) {
901			gnttab_grant_foreign_transfer_ref(ref,
902			    otherend_id, pfn);
903			sc->rx_pfn_array[nr_flips] = PFNTOMFN(pfn);
904			if (!xen_feature(XENFEAT_auto_translated_physmap)) {
905				/* Remove this page before passing
906				 * back to Xen.
907				 */
908				set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
909				MULTI_update_va_mapping(&sc->rx_mcl[i],
910				    vaddr, 0, 0);
911			}
912			nr_flips++;
913		} else {
914			gnttab_grant_foreign_access_ref(ref,
915			    otherend_id,
916			    PFNTOMFN(pfn), 0);
917		}
918		req->id = id;
919		req->gref = ref;
920
921		sc->rx_pfn_array[i] =
922		    vtomach(mtod(m_new,vm_offset_t)) >> PAGE_SHIFT;
923	}
924
925	KASSERT(i, ("no mbufs processed")); /* should have returned earlier */
926	KASSERT(mbufq_len(&sc->xn_rx_batch) == 0, ("not all mbufs processed"));
927	/*
928	 * We may have allocated buffers which have entries outstanding
929	 * in the page * update queue -- make sure we flush those first!
930	 */
931	PT_UPDATES_FLUSH();
932	if (nr_flips != 0) {
933#ifdef notyet
934		/* Tell the ballon driver what is going on. */
935		balloon_update_driver_allowance(i);
936#endif
937		set_xen_guest_handle(reservation.extent_start, sc->rx_pfn_array);
938		reservation.nr_extents   = i;
939		reservation.extent_order = 0;
940		reservation.address_bits = 0;
941		reservation.domid        = DOMID_SELF;
942
943		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
944			/* After all PTEs have been zapped, flush the TLB. */
945			sc->rx_mcl[i-1].args[MULTI_UVMFLAGS_INDEX] =
946			    UVMF_TLB_FLUSH|UVMF_ALL;
947
948			/* Give away a batch of pages. */
949			sc->rx_mcl[i].op = __HYPERVISOR_memory_op;
950			sc->rx_mcl[i].args[0] = XENMEM_decrease_reservation;
951			sc->rx_mcl[i].args[1] =  (u_long)&reservation;
952			/* Zap PTEs and give away pages in one big multicall. */
953			(void)HYPERVISOR_multicall(sc->rx_mcl, i+1);
954
955			if (__predict_false(sc->rx_mcl[i].result != i ||
956			    HYPERVISOR_memory_op(XENMEM_decrease_reservation,
957			    &reservation) != i))
958				panic("%s: unable to reduce memory "
959				    "reservation\n", __func__);
960		}
961	} else {
962		wmb();
963	}
964
965	/* Above is a suitable barrier to ensure backend will see requests. */
966	sc->rx.req_prod_pvt = req_prod + i;
967push:
968	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->rx, notify);
969	if (notify)
970		xen_intr_signal(sc->xen_intr_handle);
971}
972
973static void
974xn_rxeof(struct netfront_info *np)
975{
976	struct ifnet *ifp;
977#if __FreeBSD_version >= 700000 && (defined(INET) || defined(INET6))
978	struct lro_ctrl *lro = &np->xn_lro;
979	struct lro_entry *queued;
980#endif
981	struct netfront_rx_info rinfo;
982	struct netif_rx_response *rx = &rinfo.rx;
983	struct netif_extra_info *extras = rinfo.extras;
984	RING_IDX i, rp;
985	multicall_entry_t *mcl;
986	struct mbuf *m;
987	struct mbuf_head rxq, errq;
988	int err, pages_flipped = 0, work_to_do;
989
990	do {
991		XN_RX_LOCK_ASSERT(np);
992		if (!netfront_carrier_ok(np))
993			return;
994
995		mbufq_init(&errq);
996		mbufq_init(&rxq);
997
998		ifp = np->xn_ifp;
999
1000		rp = np->rx.sring->rsp_prod;
1001		rmb();	/* Ensure we see queued responses up to 'rp'. */
1002
1003		i = np->rx.rsp_cons;
1004		while ((i != rp)) {
1005			memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx));
1006			memset(extras, 0, sizeof(rinfo.extras));
1007
1008			m = NULL;
1009			err = xennet_get_responses(np, &rinfo, rp, &i, &m,
1010			    &pages_flipped);
1011
1012			if (__predict_false(err)) {
1013				if (m)
1014					mbufq_tail(&errq, m);
1015				np->stats.rx_errors++;
1016				continue;
1017			}
1018
1019			m->m_pkthdr.rcvif = ifp;
1020			if ( rx->flags & NETRXF_data_validated ) {
1021				/* Tell the stack the checksums are okay */
1022				/*
1023				 * XXX this isn't necessarily the case - need to add
1024				 * check
1025				 */
1026
1027				m->m_pkthdr.csum_flags |=
1028					(CSUM_IP_CHECKED | CSUM_IP_VALID | CSUM_DATA_VALID
1029					    | CSUM_PSEUDO_HDR);
1030				m->m_pkthdr.csum_data = 0xffff;
1031			}
1032
1033			np->stats.rx_packets++;
1034			np->stats.rx_bytes += m->m_pkthdr.len;
1035
1036			mbufq_tail(&rxq, m);
1037			np->rx.rsp_cons = i;
1038		}
1039
1040		if (pages_flipped) {
1041			/* Some pages are no longer absent... */
1042#ifdef notyet
1043			balloon_update_driver_allowance(-pages_flipped);
1044#endif
1045			/* Do all the remapping work, and M->P updates, in one big
1046			 * hypercall.
1047			 */
1048			if (!!xen_feature(XENFEAT_auto_translated_physmap)) {
1049				mcl = np->rx_mcl + pages_flipped;
1050				mcl->op = __HYPERVISOR_mmu_update;
1051				mcl->args[0] = (u_long)np->rx_mmu;
1052				mcl->args[1] = pages_flipped;
1053				mcl->args[2] = 0;
1054				mcl->args[3] = DOMID_SELF;
1055				(void)HYPERVISOR_multicall(np->rx_mcl,
1056				    pages_flipped + 1);
1057			}
1058		}
1059
1060		while ((m = mbufq_dequeue(&errq)))
1061			m_freem(m);
1062
1063		/*
1064		 * Process all the mbufs after the remapping is complete.
1065		 * Break the mbuf chain first though.
1066		 */
1067		while ((m = mbufq_dequeue(&rxq)) != NULL) {
1068			ifp->if_ipackets++;
1069
1070			/*
1071			 * Do we really need to drop the rx lock?
1072			 */
1073			XN_RX_UNLOCK(np);
1074#if __FreeBSD_version >= 700000 && (defined(INET) || defined(INET6))
1075			/* Use LRO if possible */
1076			if ((ifp->if_capenable & IFCAP_LRO) == 0 ||
1077			    lro->lro_cnt == 0 || tcp_lro_rx(lro, m, 0)) {
1078				/*
1079				 * If LRO fails, pass up to the stack
1080				 * directly.
1081				 */
1082				(*ifp->if_input)(ifp, m);
1083			}
1084#else
1085			(*ifp->if_input)(ifp, m);
1086#endif
1087			XN_RX_LOCK(np);
1088		}
1089
1090		np->rx.rsp_cons = i;
1091
1092#if __FreeBSD_version >= 700000 && (defined(INET) || defined(INET6))
1093		/*
1094		 * Flush any outstanding LRO work
1095		 */
1096		while (!SLIST_EMPTY(&lro->lro_active)) {
1097			queued = SLIST_FIRST(&lro->lro_active);
1098			SLIST_REMOVE_HEAD(&lro->lro_active, next);
1099			tcp_lro_flush(lro, queued);
1100		}
1101#endif
1102
1103#if 0
1104		/* If we get a callback with very few responses, reduce fill target. */
1105		/* NB. Note exponential increase, linear decrease. */
1106		if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) >
1107			((3*np->rx_target) / 4)) && (--np->rx_target < np->rx_min_target))
1108			np->rx_target = np->rx_min_target;
1109#endif
1110
1111		network_alloc_rx_buffers(np);
1112
1113		RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, work_to_do);
1114	} while (work_to_do);
1115}
1116
1117static void
1118xn_txeof(struct netfront_info *np)
1119{
1120	RING_IDX i, prod;
1121	unsigned short id;
1122	struct ifnet *ifp;
1123	netif_tx_response_t *txr;
1124	struct mbuf *m;
1125
1126	XN_TX_LOCK_ASSERT(np);
1127
1128	if (!netfront_carrier_ok(np))
1129		return;
1130
1131	ifp = np->xn_ifp;
1132
1133	do {
1134		prod = np->tx.sring->rsp_prod;
1135		rmb(); /* Ensure we see responses up to 'rp'. */
1136
1137		for (i = np->tx.rsp_cons; i != prod; i++) {
1138			txr = RING_GET_RESPONSE(&np->tx, i);
1139			if (txr->status == NETIF_RSP_NULL)
1140				continue;
1141
1142			if (txr->status != NETIF_RSP_OKAY) {
1143				printf("%s: WARNING: response is %d!\n",
1144				       __func__, txr->status);
1145			}
1146			id = txr->id;
1147			m = np->tx_mbufs[id];
1148			KASSERT(m != NULL, ("mbuf not found in xn_tx_chain"));
1149			KASSERT((uintptr_t)m > NET_TX_RING_SIZE,
1150				("mbuf already on the free list, but we're "
1151				"trying to free it again!"));
1152			M_ASSERTVALID(m);
1153
1154			/*
1155			 * Increment packet count if this is the last
1156			 * mbuf of the chain.
1157			 */
1158			if (!m->m_next)
1159				ifp->if_opackets++;
1160			if (__predict_false(gnttab_query_foreign_access(
1161			    np->grant_tx_ref[id]) != 0)) {
1162				panic("%s: grant id %u still in use by the "
1163				    "backend", __func__, id);
1164			}
1165			gnttab_end_foreign_access_ref(
1166				np->grant_tx_ref[id]);
1167			gnttab_release_grant_reference(
1168				&np->gref_tx_head, np->grant_tx_ref[id]);
1169			np->grant_tx_ref[id] = GRANT_REF_INVALID;
1170
1171			np->tx_mbufs[id] = NULL;
1172			add_id_to_freelist(np->tx_mbufs, id);
1173			np->xn_cdata.xn_tx_chain_cnt--;
1174			m_free(m);
1175			/* Only mark the queue active if we've freed up at least one slot to try */
1176			ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
1177		}
1178		np->tx.rsp_cons = prod;
1179
1180		/*
1181		 * Set a new event, then check for race with update of
1182		 * tx_cons. Note that it is essential to schedule a
1183		 * callback, no matter how few buffers are pending. Even if
1184		 * there is space in the transmit ring, higher layers may
1185		 * be blocked because too much data is outstanding: in such
1186		 * cases notification from Xen is likely to be the only kick
1187		 * that we'll get.
1188		 */
1189		np->tx.sring->rsp_event =
1190		    prod + ((np->tx.sring->req_prod - prod) >> 1) + 1;
1191
1192		mb();
1193	} while (prod != np->tx.sring->rsp_prod);
1194
1195	if (np->tx_full &&
1196	    ((np->tx.sring->req_prod - prod) < NET_TX_RING_SIZE)) {
1197		np->tx_full = 0;
1198#if 0
1199		if (np->user_state == UST_OPEN)
1200			netif_wake_queue(dev);
1201#endif
1202	}
1203}
1204
1205static void
1206xn_intr(void *xsc)
1207{
1208	struct netfront_info *np = xsc;
1209	struct ifnet *ifp = np->xn_ifp;
1210
1211#if 0
1212	if (!(np->rx.rsp_cons != np->rx.sring->rsp_prod &&
1213	    likely(netfront_carrier_ok(np)) &&
1214	    ifp->if_drv_flags & IFF_DRV_RUNNING))
1215		return;
1216#endif
1217	if (RING_HAS_UNCONSUMED_RESPONSES(&np->tx)) {
1218		XN_TX_LOCK(np);
1219		xn_txeof(np);
1220		XN_TX_UNLOCK(np);
1221	}
1222
1223	XN_RX_LOCK(np);
1224	xn_rxeof(np);
1225	XN_RX_UNLOCK(np);
1226
1227	if (ifp->if_drv_flags & IFF_DRV_RUNNING &&
1228	    !IFQ_DRV_IS_EMPTY(&ifp->if_snd))
1229		xn_start(ifp);
1230}
1231
1232static void
1233xennet_move_rx_slot(struct netfront_info *np, struct mbuf *m,
1234	grant_ref_t ref)
1235{
1236	int new = xennet_rxidx(np->rx.req_prod_pvt);
1237
1238	KASSERT(np->rx_mbufs[new] == NULL, ("rx_mbufs != NULL"));
1239	np->rx_mbufs[new] = m;
1240	np->grant_rx_ref[new] = ref;
1241	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
1242	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
1243	np->rx.req_prod_pvt++;
1244}
1245
1246static int
1247xennet_get_extras(struct netfront_info *np,
1248    struct netif_extra_info *extras, RING_IDX rp, RING_IDX *cons)
1249{
1250	struct netif_extra_info *extra;
1251
1252	int err = 0;
1253
1254	do {
1255		struct mbuf *m;
1256		grant_ref_t ref;
1257
1258		if (__predict_false(*cons + 1 == rp)) {
1259#if 0
1260			if (net_ratelimit())
1261				WPRINTK("Missing extra info\n");
1262#endif
1263			err = EINVAL;
1264			break;
1265		}
1266
1267		extra = (struct netif_extra_info *)
1268		RING_GET_RESPONSE(&np->rx, ++(*cons));
1269
1270		if (__predict_false(!extra->type ||
1271			extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1272#if 0
1273			if (net_ratelimit())
1274				WPRINTK("Invalid extra type: %d\n",
1275					extra->type);
1276#endif
1277			err = EINVAL;
1278		} else {
1279			memcpy(&extras[extra->type - 1], extra, sizeof(*extra));
1280		}
1281
1282		m = xennet_get_rx_mbuf(np, *cons);
1283		ref = xennet_get_rx_ref(np, *cons);
1284		xennet_move_rx_slot(np, m, ref);
1285	} while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
1286
1287	return err;
1288}
1289
1290static int
1291xennet_get_responses(struct netfront_info *np,
1292	struct netfront_rx_info *rinfo, RING_IDX rp, RING_IDX *cons,
1293	struct mbuf  **list,
1294	int *pages_flipped_p)
1295{
1296	int pages_flipped = *pages_flipped_p;
1297	struct mmu_update *mmu;
1298	struct multicall_entry *mcl;
1299	struct netif_rx_response *rx = &rinfo->rx;
1300	struct netif_extra_info *extras = rinfo->extras;
1301	struct mbuf *m, *m0, *m_prev;
1302	grant_ref_t ref = xennet_get_rx_ref(np, *cons);
1303	RING_IDX ref_cons = *cons;
1304	int frags = 1;
1305	int err = 0;
1306	u_long ret;
1307
1308	m0 = m = m_prev = xennet_get_rx_mbuf(np, *cons);
1309
1310	if (rx->flags & NETRXF_extra_info) {
1311		err = xennet_get_extras(np, extras, rp, cons);
1312	}
1313
1314	if (m0 != NULL) {
1315		m0->m_pkthdr.len = 0;
1316		m0->m_next = NULL;
1317	}
1318
1319	for (;;) {
1320		u_long mfn;
1321
1322#if 0
1323		DPRINTK("rx->status=%hd rx->offset=%hu frags=%u\n",
1324			rx->status, rx->offset, frags);
1325#endif
1326		if (__predict_false(rx->status < 0 ||
1327			rx->offset + rx->status > PAGE_SIZE)) {
1328
1329#if 0
1330			if (net_ratelimit())
1331				WPRINTK("rx->offset: %x, size: %u\n",
1332					rx->offset, rx->status);
1333#endif
1334			xennet_move_rx_slot(np, m, ref);
1335			if (m0 == m)
1336				m0 = NULL;
1337			m = NULL;
1338			err = EINVAL;
1339			goto next_skip_queue;
1340		}
1341
1342		/*
1343		 * This definitely indicates a bug, either in this driver or in
1344		 * the backend driver. In future this should flag the bad
1345		 * situation to the system controller to reboot the backed.
1346		 */
1347		if (ref == GRANT_REF_INVALID) {
1348
1349#if 0
1350			if (net_ratelimit())
1351				WPRINTK("Bad rx response id %d.\n", rx->id);
1352#endif
1353			printf("%s: Bad rx response id %d.\n", __func__,rx->id);
1354			err = EINVAL;
1355			goto next;
1356		}
1357
1358		if (!np->copying_receiver) {
1359			/* Memory pressure, insufficient buffer
1360			 * headroom, ...
1361			 */
1362			if (!(mfn = gnttab_end_foreign_transfer_ref(ref))) {
1363				WPRINTK("Unfulfilled rx req (id=%d, st=%d).\n",
1364					rx->id, rx->status);
1365				xennet_move_rx_slot(np, m, ref);
1366				err = ENOMEM;
1367				goto next;
1368			}
1369
1370			if (!xen_feature( XENFEAT_auto_translated_physmap)) {
1371				/* Remap the page. */
1372				void *vaddr = mtod(m, void *);
1373				uint32_t pfn;
1374
1375				mcl = np->rx_mcl + pages_flipped;
1376				mmu = np->rx_mmu + pages_flipped;
1377
1378				MULTI_update_va_mapping(mcl, (u_long)vaddr,
1379				    (((vm_paddr_t)mfn) << PAGE_SHIFT) | PG_RW |
1380				    PG_V | PG_M | PG_A, 0);
1381				pfn = (uintptr_t)m->m_ext.ext_arg1;
1382				mmu->ptr = ((vm_paddr_t)mfn << PAGE_SHIFT) |
1383				    MMU_MACHPHYS_UPDATE;
1384				mmu->val = pfn;
1385
1386				set_phys_to_machine(pfn, mfn);
1387			}
1388			pages_flipped++;
1389		} else {
1390			ret = gnttab_end_foreign_access_ref(ref);
1391			KASSERT(ret, ("ret != 0"));
1392		}
1393
1394		gnttab_release_grant_reference(&np->gref_rx_head, ref);
1395
1396next:
1397		if (m == NULL)
1398			break;
1399
1400		m->m_len = rx->status;
1401		m->m_data += rx->offset;
1402		m0->m_pkthdr.len += rx->status;
1403
1404next_skip_queue:
1405		if (!(rx->flags & NETRXF_more_data))
1406			break;
1407
1408		if (*cons + frags == rp) {
1409			if (net_ratelimit())
1410				WPRINTK("Need more frags\n");
1411			err = ENOENT;
1412			printf("%s: cons %u frags %u rp %u, not enough frags\n",
1413			       __func__, *cons, frags, rp);
1414			break;
1415		}
1416		/*
1417		 * Note that m can be NULL, if rx->status < 0 or if
1418		 * rx->offset + rx->status > PAGE_SIZE above.
1419		 */
1420		m_prev = m;
1421
1422		rx = RING_GET_RESPONSE(&np->rx, *cons + frags);
1423		m = xennet_get_rx_mbuf(np, *cons + frags);
1424
1425		/*
1426		 * m_prev == NULL can happen if rx->status < 0 or if
1427		 * rx->offset + * rx->status > PAGE_SIZE above.
1428		 */
1429		if (m_prev != NULL)
1430			m_prev->m_next = m;
1431
1432		/*
1433		 * m0 can be NULL if rx->status < 0 or if * rx->offset +
1434		 * rx->status > PAGE_SIZE above.
1435		 */
1436		if (m0 == NULL)
1437			m0 = m;
1438		m->m_next = NULL;
1439		ref = xennet_get_rx_ref(np, *cons + frags);
1440		ref_cons = *cons + frags;
1441		frags++;
1442	}
1443	*list = m0;
1444	*cons += frags;
1445	*pages_flipped_p = pages_flipped;
1446
1447	return (err);
1448}
1449
1450static void
1451xn_tick_locked(struct netfront_info *sc)
1452{
1453	XN_RX_LOCK_ASSERT(sc);
1454	callout_reset(&sc->xn_stat_ch, hz, xn_tick, sc);
1455
1456	/* XXX placeholder for printing debug information */
1457}
1458
1459static void
1460xn_tick(void *xsc)
1461{
1462	struct netfront_info *sc;
1463
1464	sc = xsc;
1465	XN_RX_LOCK(sc);
1466	xn_tick_locked(sc);
1467	XN_RX_UNLOCK(sc);
1468}
1469
1470/**
1471 * \brief Count the number of fragments in an mbuf chain.
1472 *
1473 * Surprisingly, there isn't an M* macro for this.
1474 */
1475static inline int
1476xn_count_frags(struct mbuf *m)
1477{
1478	int nfrags;
1479
1480	for (nfrags = 0; m != NULL; m = m->m_next)
1481		nfrags++;
1482
1483	return (nfrags);
1484}
1485
1486/**
1487 * Given an mbuf chain, make sure we have enough room and then push
1488 * it onto the transmit ring.
1489 */
1490static int
1491xn_assemble_tx_request(struct netfront_info *sc, struct mbuf *m_head)
1492{
1493	struct ifnet *ifp;
1494	struct mbuf *m;
1495	u_int nfrags;
1496	netif_extra_info_t *extra;
1497	int otherend_id;
1498
1499	ifp = sc->xn_ifp;
1500
1501	/**
1502	 * Defragment the mbuf if necessary.
1503	 */
1504	nfrags = xn_count_frags(m_head);
1505
1506	/*
1507	 * Check to see whether this request is longer than netback
1508	 * can handle, and try to defrag it.
1509	 */
1510	/**
1511	 * It is a bit lame, but the netback driver in Linux can't
1512	 * deal with nfrags > MAX_TX_REQ_FRAGS, which is a quirk of
1513	 * the Linux network stack.
1514	 */
1515	if (nfrags > sc->maxfrags) {
1516		m = m_defrag(m_head, M_NOWAIT);
1517		if (!m) {
1518			/*
1519			 * Defrag failed, so free the mbuf and
1520			 * therefore drop the packet.
1521			 */
1522			m_freem(m_head);
1523			return (EMSGSIZE);
1524		}
1525		m_head = m;
1526	}
1527
1528	/* Determine how many fragments now exist */
1529	nfrags = xn_count_frags(m_head);
1530
1531	/*
1532	 * Check to see whether the defragmented packet has too many
1533	 * segments for the Linux netback driver.
1534	 */
1535	/**
1536	 * The FreeBSD TCP stack, with TSO enabled, can produce a chain
1537	 * of mbufs longer than Linux can handle.  Make sure we don't
1538	 * pass a too-long chain over to the other side by dropping the
1539	 * packet.  It doesn't look like there is currently a way to
1540	 * tell the TCP stack to generate a shorter chain of packets.
1541	 */
1542	if (nfrags > MAX_TX_REQ_FRAGS) {
1543#ifdef DEBUG
1544		printf("%s: nfrags %d > MAX_TX_REQ_FRAGS %d, netback "
1545		       "won't be able to handle it, dropping\n",
1546		       __func__, nfrags, MAX_TX_REQ_FRAGS);
1547#endif
1548		m_freem(m_head);
1549		return (EMSGSIZE);
1550	}
1551
1552	/*
1553	 * This check should be redundant.  We've already verified that we
1554	 * have enough slots in the ring to handle a packet of maximum
1555	 * size, and that our packet is less than the maximum size.  Keep
1556	 * it in here as an assert for now just to make certain that
1557	 * xn_tx_chain_cnt is accurate.
1558	 */
1559	KASSERT((sc->xn_cdata.xn_tx_chain_cnt + nfrags) <= NET_TX_RING_SIZE,
1560		("%s: xn_tx_chain_cnt (%d) + nfrags (%d) > NET_TX_RING_SIZE "
1561		 "(%d)!", __func__, (int) sc->xn_cdata.xn_tx_chain_cnt,
1562                    (int) nfrags, (int) NET_TX_RING_SIZE));
1563
1564	/*
1565	 * Start packing the mbufs in this chain into
1566	 * the fragment pointers. Stop when we run out
1567	 * of fragments or hit the end of the mbuf chain.
1568	 */
1569	m = m_head;
1570	extra = NULL;
1571	otherend_id = xenbus_get_otherend_id(sc->xbdev);
1572	for (m = m_head; m; m = m->m_next) {
1573		netif_tx_request_t *tx;
1574		uintptr_t id;
1575		grant_ref_t ref;
1576		u_long mfn; /* XXX Wrong type? */
1577
1578		tx = RING_GET_REQUEST(&sc->tx, sc->tx.req_prod_pvt);
1579		id = get_id_from_freelist(sc->tx_mbufs);
1580		if (id == 0)
1581			panic("%s: was allocated the freelist head!\n",
1582			    __func__);
1583		sc->xn_cdata.xn_tx_chain_cnt++;
1584		if (sc->xn_cdata.xn_tx_chain_cnt > NET_TX_RING_SIZE)
1585			panic("%s: tx_chain_cnt must be <= NET_TX_RING_SIZE\n",
1586			    __func__);
1587		sc->tx_mbufs[id] = m;
1588		tx->id = id;
1589		ref = gnttab_claim_grant_reference(&sc->gref_tx_head);
1590		KASSERT((short)ref >= 0, ("Negative ref"));
1591		mfn = virt_to_mfn(mtod(m, vm_offset_t));
1592		gnttab_grant_foreign_access_ref(ref, otherend_id,
1593		    mfn, GNTMAP_readonly);
1594		tx->gref = sc->grant_tx_ref[id] = ref;
1595		tx->offset = mtod(m, vm_offset_t) & (PAGE_SIZE - 1);
1596		tx->flags = 0;
1597		if (m == m_head) {
1598			/*
1599			 * The first fragment has the entire packet
1600			 * size, subsequent fragments have just the
1601			 * fragment size. The backend works out the
1602			 * true size of the first fragment by
1603			 * subtracting the sizes of the other
1604			 * fragments.
1605			 */
1606			tx->size = m->m_pkthdr.len;
1607
1608			/*
1609			 * The first fragment contains the checksum flags
1610			 * and is optionally followed by extra data for
1611			 * TSO etc.
1612			 */
1613			/**
1614			 * CSUM_TSO requires checksum offloading.
1615			 * Some versions of FreeBSD fail to
1616			 * set CSUM_TCP in the CSUM_TSO case,
1617			 * so we have to test for CSUM_TSO
1618			 * explicitly.
1619			 */
1620			if (m->m_pkthdr.csum_flags
1621			    & (CSUM_DELAY_DATA | CSUM_TSO)) {
1622				tx->flags |= (NETTXF_csum_blank
1623				    | NETTXF_data_validated);
1624			}
1625#if __FreeBSD_version >= 700000
1626			if (m->m_pkthdr.csum_flags & CSUM_TSO) {
1627				struct netif_extra_info *gso =
1628					(struct netif_extra_info *)
1629					RING_GET_REQUEST(&sc->tx,
1630							 ++sc->tx.req_prod_pvt);
1631
1632				tx->flags |= NETTXF_extra_info;
1633
1634				gso->u.gso.size = m->m_pkthdr.tso_segsz;
1635				gso->u.gso.type =
1636					XEN_NETIF_GSO_TYPE_TCPV4;
1637				gso->u.gso.pad = 0;
1638				gso->u.gso.features = 0;
1639
1640				gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
1641				gso->flags = 0;
1642			}
1643#endif
1644		} else {
1645			tx->size = m->m_len;
1646		}
1647		if (m->m_next)
1648			tx->flags |= NETTXF_more_data;
1649
1650		sc->tx.req_prod_pvt++;
1651	}
1652	BPF_MTAP(ifp, m_head);
1653
1654	sc->stats.tx_bytes += m_head->m_pkthdr.len;
1655	sc->stats.tx_packets++;
1656
1657	return (0);
1658}
1659
1660static void
1661xn_start_locked(struct ifnet *ifp)
1662{
1663	struct netfront_info *sc;
1664	struct mbuf *m_head;
1665	int notify;
1666
1667	sc = ifp->if_softc;
1668
1669	if (!netfront_carrier_ok(sc))
1670		return;
1671
1672	/*
1673	 * While we have enough transmit slots available for at least one
1674	 * maximum-sized packet, pull mbufs off the queue and put them on
1675	 * the transmit ring.
1676	 */
1677	while (xn_tx_slot_available(sc)) {
1678		IF_DEQUEUE(&ifp->if_snd, m_head);
1679		if (m_head == NULL)
1680			break;
1681
1682		if (xn_assemble_tx_request(sc, m_head) != 0)
1683			break;
1684	}
1685
1686	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->tx, notify);
1687	if (notify)
1688		xen_intr_signal(sc->xen_intr_handle);
1689
1690	if (RING_FULL(&sc->tx)) {
1691		sc->tx_full = 1;
1692#if 0
1693		netif_stop_queue(dev);
1694#endif
1695	}
1696}
1697
1698static void
1699xn_start(struct ifnet *ifp)
1700{
1701	struct netfront_info *sc;
1702	sc = ifp->if_softc;
1703	XN_TX_LOCK(sc);
1704	xn_start_locked(ifp);
1705	XN_TX_UNLOCK(sc);
1706}
1707
1708/* equivalent of network_open() in Linux */
1709static void
1710xn_ifinit_locked(struct netfront_info *sc)
1711{
1712	struct ifnet *ifp;
1713
1714	XN_LOCK_ASSERT(sc);
1715
1716	ifp = sc->xn_ifp;
1717
1718	if (ifp->if_drv_flags & IFF_DRV_RUNNING)
1719		return;
1720
1721	xn_stop(sc);
1722
1723	network_alloc_rx_buffers(sc);
1724	sc->rx.sring->rsp_event = sc->rx.rsp_cons + 1;
1725
1726	ifp->if_drv_flags |= IFF_DRV_RUNNING;
1727	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
1728	if_link_state_change(ifp, LINK_STATE_UP);
1729
1730	callout_reset(&sc->xn_stat_ch, hz, xn_tick, sc);
1731}
1732
1733static void
1734xn_ifinit(void *xsc)
1735{
1736	struct netfront_info *sc = xsc;
1737
1738	XN_LOCK(sc);
1739	xn_ifinit_locked(sc);
1740	XN_UNLOCK(sc);
1741}
1742
1743static int
1744xn_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
1745{
1746	struct netfront_info *sc = ifp->if_softc;
1747	struct ifreq *ifr = (struct ifreq *) data;
1748#ifdef INET
1749	struct ifaddr *ifa = (struct ifaddr *)data;
1750#endif
1751
1752	int mask, error = 0;
1753	switch(cmd) {
1754	case SIOCSIFADDR:
1755	case SIOCGIFADDR:
1756#ifdef INET
1757		XN_LOCK(sc);
1758		if (ifa->ifa_addr->sa_family == AF_INET) {
1759			ifp->if_flags |= IFF_UP;
1760			if (!(ifp->if_drv_flags & IFF_DRV_RUNNING))
1761				xn_ifinit_locked(sc);
1762			arp_ifinit(ifp, ifa);
1763			XN_UNLOCK(sc);
1764		} else {
1765			XN_UNLOCK(sc);
1766#endif
1767			error = ether_ioctl(ifp, cmd, data);
1768#ifdef INET
1769		}
1770#endif
1771		break;
1772	case SIOCSIFMTU:
1773		/* XXX can we alter the MTU on a VN ?*/
1774#ifdef notyet
1775		if (ifr->ifr_mtu > XN_JUMBO_MTU)
1776			error = EINVAL;
1777		else
1778#endif
1779		{
1780			ifp->if_mtu = ifr->ifr_mtu;
1781			ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
1782			xn_ifinit(sc);
1783		}
1784		break;
1785	case SIOCSIFFLAGS:
1786		XN_LOCK(sc);
1787		if (ifp->if_flags & IFF_UP) {
1788			/*
1789			 * If only the state of the PROMISC flag changed,
1790			 * then just use the 'set promisc mode' command
1791			 * instead of reinitializing the entire NIC. Doing
1792			 * a full re-init means reloading the firmware and
1793			 * waiting for it to start up, which may take a
1794			 * second or two.
1795			 */
1796#ifdef notyet
1797			/* No promiscuous mode with Xen */
1798			if (ifp->if_drv_flags & IFF_DRV_RUNNING &&
1799			    ifp->if_flags & IFF_PROMISC &&
1800			    !(sc->xn_if_flags & IFF_PROMISC)) {
1801				XN_SETBIT(sc, XN_RX_MODE,
1802					  XN_RXMODE_RX_PROMISC);
1803			} else if (ifp->if_drv_flags & IFF_DRV_RUNNING &&
1804				   !(ifp->if_flags & IFF_PROMISC) &&
1805				   sc->xn_if_flags & IFF_PROMISC) {
1806				XN_CLRBIT(sc, XN_RX_MODE,
1807					  XN_RXMODE_RX_PROMISC);
1808			} else
1809#endif
1810				xn_ifinit_locked(sc);
1811		} else {
1812			if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
1813				xn_stop(sc);
1814			}
1815		}
1816		sc->xn_if_flags = ifp->if_flags;
1817		XN_UNLOCK(sc);
1818		error = 0;
1819		break;
1820	case SIOCSIFCAP:
1821		mask = ifr->ifr_reqcap ^ ifp->if_capenable;
1822		if (mask & IFCAP_TXCSUM) {
1823			if (IFCAP_TXCSUM & ifp->if_capenable) {
1824				ifp->if_capenable &= ~(IFCAP_TXCSUM|IFCAP_TSO4);
1825				ifp->if_hwassist &= ~(CSUM_TCP | CSUM_UDP
1826				    | CSUM_IP | CSUM_TSO);
1827			} else {
1828				ifp->if_capenable |= IFCAP_TXCSUM;
1829				ifp->if_hwassist |= (CSUM_TCP | CSUM_UDP
1830				    | CSUM_IP);
1831			}
1832		}
1833		if (mask & IFCAP_RXCSUM) {
1834			ifp->if_capenable ^= IFCAP_RXCSUM;
1835		}
1836#if __FreeBSD_version >= 700000
1837		if (mask & IFCAP_TSO4) {
1838			if (IFCAP_TSO4 & ifp->if_capenable) {
1839				ifp->if_capenable &= ~IFCAP_TSO4;
1840				ifp->if_hwassist &= ~CSUM_TSO;
1841			} else if (IFCAP_TXCSUM & ifp->if_capenable) {
1842				ifp->if_capenable |= IFCAP_TSO4;
1843				ifp->if_hwassist |= CSUM_TSO;
1844			} else {
1845				IPRINTK("Xen requires tx checksum offload"
1846				    " be enabled to use TSO\n");
1847				error = EINVAL;
1848			}
1849		}
1850		if (mask & IFCAP_LRO) {
1851			ifp->if_capenable ^= IFCAP_LRO;
1852
1853		}
1854#endif
1855		error = 0;
1856		break;
1857	case SIOCADDMULTI:
1858	case SIOCDELMULTI:
1859#ifdef notyet
1860		if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
1861			XN_LOCK(sc);
1862			xn_setmulti(sc);
1863			XN_UNLOCK(sc);
1864			error = 0;
1865		}
1866#endif
1867		/* FALLTHROUGH */
1868	case SIOCSIFMEDIA:
1869	case SIOCGIFMEDIA:
1870		error = ifmedia_ioctl(ifp, ifr, &sc->sc_media, cmd);
1871		break;
1872	default:
1873		error = ether_ioctl(ifp, cmd, data);
1874	}
1875
1876	return (error);
1877}
1878
1879static void
1880xn_stop(struct netfront_info *sc)
1881{
1882	struct ifnet *ifp;
1883
1884	XN_LOCK_ASSERT(sc);
1885
1886	ifp = sc->xn_ifp;
1887
1888	callout_stop(&sc->xn_stat_ch);
1889
1890	xn_free_rx_ring(sc);
1891	xn_free_tx_ring(sc);
1892
1893	ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
1894	if_link_state_change(ifp, LINK_STATE_DOWN);
1895}
1896
1897/* START of Xenolinux helper functions adapted to FreeBSD */
1898int
1899network_connect(struct netfront_info *np)
1900{
1901	int i, requeue_idx, error;
1902	grant_ref_t ref;
1903	netif_rx_request_t *req;
1904	u_int feature_rx_copy, feature_rx_flip;
1905
1906	error = xs_scanf(XST_NIL, xenbus_get_otherend_path(np->xbdev),
1907	    "feature-rx-copy", NULL, "%u", &feature_rx_copy);
1908	if (error)
1909		feature_rx_copy = 0;
1910	error = xs_scanf(XST_NIL, xenbus_get_otherend_path(np->xbdev),
1911	    "feature-rx-flip", NULL, "%u", &feature_rx_flip);
1912	if (error)
1913		feature_rx_flip = 1;
1914
1915	/*
1916	 * Copy packets on receive path if:
1917	 *  (a) This was requested by user, and the backend supports it; or
1918	 *  (b) Flipping was requested, but this is unsupported by the backend.
1919	 */
1920	np->copying_receiver = ((MODPARM_rx_copy && feature_rx_copy) ||
1921				(MODPARM_rx_flip && !feature_rx_flip));
1922
1923	/* Recovery procedure: */
1924	error = talk_to_backend(np->xbdev, np);
1925	if (error)
1926		return (error);
1927
1928	/* Step 1: Reinitialise variables. */
1929	xn_query_features(np);
1930	xn_configure_features(np);
1931	netif_release_tx_bufs(np);
1932
1933	/* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
1934	for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
1935		struct mbuf *m;
1936		u_long pfn;
1937
1938		if (np->rx_mbufs[i] == NULL)
1939			continue;
1940
1941		m = np->rx_mbufs[requeue_idx] = xennet_get_rx_mbuf(np, i);
1942		ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i);
1943
1944		req = RING_GET_REQUEST(&np->rx, requeue_idx);
1945		pfn = vtophys(mtod(m, vm_offset_t)) >> PAGE_SHIFT;
1946
1947		if (!np->copying_receiver) {
1948			gnttab_grant_foreign_transfer_ref(ref,
1949			    xenbus_get_otherend_id(np->xbdev),
1950			    pfn);
1951		} else {
1952			gnttab_grant_foreign_access_ref(ref,
1953			    xenbus_get_otherend_id(np->xbdev),
1954			    PFNTOMFN(pfn), 0);
1955		}
1956		req->gref = ref;
1957		req->id   = requeue_idx;
1958
1959		requeue_idx++;
1960	}
1961
1962	np->rx.req_prod_pvt = requeue_idx;
1963
1964	/* Step 3: All public and private state should now be sane.  Get
1965	 * ready to start sending and receiving packets and give the driver
1966	 * domain a kick because we've probably just requeued some
1967	 * packets.
1968	 */
1969	netfront_carrier_on(np);
1970	xen_intr_signal(np->xen_intr_handle);
1971	XN_TX_LOCK(np);
1972	xn_txeof(np);
1973	XN_TX_UNLOCK(np);
1974	network_alloc_rx_buffers(np);
1975
1976	return (0);
1977}
1978
1979static void
1980xn_query_features(struct netfront_info *np)
1981{
1982	int val;
1983
1984	device_printf(np->xbdev, "backend features:");
1985
1986	if (xs_scanf(XST_NIL, xenbus_get_otherend_path(np->xbdev),
1987		"feature-sg", NULL, "%d", &val) < 0)
1988		val = 0;
1989
1990	np->maxfrags = 1;
1991	if (val) {
1992		np->maxfrags = MAX_TX_REQ_FRAGS;
1993		printf(" feature-sg");
1994	}
1995
1996	if (xs_scanf(XST_NIL, xenbus_get_otherend_path(np->xbdev),
1997		"feature-gso-tcpv4", NULL, "%d", &val) < 0)
1998		val = 0;
1999
2000	np->xn_ifp->if_capabilities &= ~(IFCAP_TSO4|IFCAP_LRO);
2001	if (val) {
2002		np->xn_ifp->if_capabilities |= IFCAP_TSO4|IFCAP_LRO;
2003		printf(" feature-gso-tcp4");
2004	}
2005
2006	printf("\n");
2007}
2008
2009static int
2010xn_configure_features(struct netfront_info *np)
2011{
2012	int err, cap_enabled;
2013
2014	err = 0;
2015
2016	if (np->xn_resume &&
2017	    ((np->xn_ifp->if_capenable & np->xn_ifp->if_capabilities)
2018	    == np->xn_ifp->if_capenable)) {
2019		/* Current options are available, no need to do anything. */
2020		return (0);
2021	}
2022
2023	/* Try to preserve as many options as possible. */
2024	if (np->xn_resume)
2025		cap_enabled = np->xn_ifp->if_capenable;
2026	else
2027		cap_enabled = UINT_MAX;
2028
2029#if __FreeBSD_version >= 700000 && (defined(INET) || defined(INET6))
2030	if ((np->xn_ifp->if_capenable & IFCAP_LRO) == (cap_enabled & IFCAP_LRO))
2031		tcp_lro_free(&np->xn_lro);
2032#endif
2033    	np->xn_ifp->if_capenable =
2034	    np->xn_ifp->if_capabilities & ~(IFCAP_LRO|IFCAP_TSO4) & cap_enabled;
2035	np->xn_ifp->if_hwassist &= ~CSUM_TSO;
2036#if __FreeBSD_version >= 700000 && (defined(INET) || defined(INET6))
2037	if (xn_enable_lro && (np->xn_ifp->if_capabilities & IFCAP_LRO) ==
2038	    (cap_enabled & IFCAP_LRO)) {
2039		err = tcp_lro_init(&np->xn_lro);
2040		if (err) {
2041			device_printf(np->xbdev, "LRO initialization failed\n");
2042		} else {
2043			np->xn_lro.ifp = np->xn_ifp;
2044			np->xn_ifp->if_capenable |= IFCAP_LRO;
2045		}
2046	}
2047	if ((np->xn_ifp->if_capabilities & IFCAP_TSO4) ==
2048	    (cap_enabled & IFCAP_TSO4)) {
2049		np->xn_ifp->if_capenable |= IFCAP_TSO4;
2050		np->xn_ifp->if_hwassist |= CSUM_TSO;
2051	}
2052#endif
2053	return (err);
2054}
2055
2056/**
2057 * Create a network device.
2058 * @param dev  Newbus device representing this virtual NIC.
2059 */
2060int
2061create_netdev(device_t dev)
2062{
2063	int i;
2064	struct netfront_info *np;
2065	int err;
2066	struct ifnet *ifp;
2067
2068	np = device_get_softc(dev);
2069
2070	np->xbdev         = dev;
2071
2072	XN_LOCK_INIT(np, xennetif);
2073
2074	ifmedia_init(&np->sc_media, 0, xn_ifmedia_upd, xn_ifmedia_sts);
2075	ifmedia_add(&np->sc_media, IFM_ETHER|IFM_MANUAL, 0, NULL);
2076	ifmedia_set(&np->sc_media, IFM_ETHER|IFM_MANUAL);
2077
2078	np->rx_target     = RX_MIN_TARGET;
2079	np->rx_min_target = RX_MIN_TARGET;
2080	np->rx_max_target = RX_MAX_TARGET;
2081
2082	/* Initialise {tx,rx}_skbs to be a free chain containing every entry. */
2083	for (i = 0; i <= NET_TX_RING_SIZE; i++) {
2084		np->tx_mbufs[i] = (void *) ((u_long) i+1);
2085		np->grant_tx_ref[i] = GRANT_REF_INVALID;
2086	}
2087	np->tx_mbufs[NET_TX_RING_SIZE] = (void *)0;
2088
2089	for (i = 0; i <= NET_RX_RING_SIZE; i++) {
2090
2091		np->rx_mbufs[i] = NULL;
2092		np->grant_rx_ref[i] = GRANT_REF_INVALID;
2093	}
2094	/* A grant for every tx ring slot */
2095	if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
2096					  &np->gref_tx_head) != 0) {
2097		IPRINTK("#### netfront can't alloc tx grant refs\n");
2098		err = ENOMEM;
2099		goto exit;
2100	}
2101	/* A grant for every rx ring slot */
2102	if (gnttab_alloc_grant_references(RX_MAX_TARGET,
2103					  &np->gref_rx_head) != 0) {
2104		WPRINTK("#### netfront can't alloc rx grant refs\n");
2105		gnttab_free_grant_references(np->gref_tx_head);
2106		err = ENOMEM;
2107		goto exit;
2108	}
2109
2110	err = xen_net_read_mac(dev, np->mac);
2111	if (err)
2112		goto out;
2113
2114	/* Set up ifnet structure */
2115	ifp = np->xn_ifp = if_alloc(IFT_ETHER);
2116    	ifp->if_softc = np;
2117    	if_initname(ifp, "xn",  device_get_unit(dev));
2118    	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
2119    	ifp->if_ioctl = xn_ioctl;
2120    	ifp->if_output = ether_output;
2121    	ifp->if_start = xn_start;
2122#ifdef notyet
2123    	ifp->if_watchdog = xn_watchdog;
2124#endif
2125    	ifp->if_init = xn_ifinit;
2126    	ifp->if_snd.ifq_maxlen = NET_TX_RING_SIZE - 1;
2127
2128    	ifp->if_hwassist = XN_CSUM_FEATURES;
2129    	ifp->if_capabilities = IFCAP_HWCSUM;
2130	ifp->if_hw_tsomax = 65536 - (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN);
2131	ifp->if_hw_tsomaxsegcount = MAX_TX_REQ_FRAGS;
2132	ifp->if_hw_tsomaxsegsize = PAGE_SIZE;
2133
2134    	ether_ifattach(ifp, np->mac);
2135    	callout_init(&np->xn_stat_ch, CALLOUT_MPSAFE);
2136	netfront_carrier_off(np);
2137
2138	return (0);
2139
2140exit:
2141	gnttab_free_grant_references(np->gref_tx_head);
2142out:
2143	return (err);
2144}
2145
2146/**
2147 * Handle the change of state of the backend to Closing.  We must delete our
2148 * device-layer structures now, to ensure that writes are flushed through to
2149 * the backend.  Once is this done, we can switch to Closed in
2150 * acknowledgement.
2151 */
2152#if 0
2153static void
2154netfront_closing(device_t dev)
2155{
2156#if 0
2157	struct netfront_info *info = dev->dev_driver_data;
2158
2159	DPRINTK("netfront_closing: %s removed\n", dev->nodename);
2160
2161	close_netdev(info);
2162#endif
2163	xenbus_switch_state(dev, XenbusStateClosed);
2164}
2165#endif
2166
2167static int
2168netfront_detach(device_t dev)
2169{
2170	struct netfront_info *info = device_get_softc(dev);
2171
2172	DPRINTK("%s\n", xenbus_get_node(dev));
2173
2174	netif_free(info);
2175
2176	return 0;
2177}
2178
2179static void
2180netif_free(struct netfront_info *info)
2181{
2182	XN_LOCK(info);
2183	xn_stop(info);
2184	XN_UNLOCK(info);
2185	callout_drain(&info->xn_stat_ch);
2186	netif_disconnect_backend(info);
2187	if (info->xn_ifp != NULL) {
2188		ether_ifdetach(info->xn_ifp);
2189		if_free(info->xn_ifp);
2190		info->xn_ifp = NULL;
2191	}
2192	ifmedia_removeall(&info->sc_media);
2193}
2194
2195static void
2196netif_disconnect_backend(struct netfront_info *info)
2197{
2198	XN_RX_LOCK(info);
2199	XN_TX_LOCK(info);
2200	netfront_carrier_off(info);
2201	XN_TX_UNLOCK(info);
2202	XN_RX_UNLOCK(info);
2203
2204	free_ring(&info->tx_ring_ref, &info->tx.sring);
2205	free_ring(&info->rx_ring_ref, &info->rx.sring);
2206
2207	xen_intr_unbind(&info->xen_intr_handle);
2208}
2209
2210static void
2211free_ring(int *ref, void *ring_ptr_ref)
2212{
2213	void **ring_ptr_ptr = ring_ptr_ref;
2214
2215	if (*ref != GRANT_REF_INVALID) {
2216		/* This API frees the associated storage. */
2217		gnttab_end_foreign_access(*ref, *ring_ptr_ptr);
2218		*ref = GRANT_REF_INVALID;
2219	}
2220	*ring_ptr_ptr = NULL;
2221}
2222
2223static int
2224xn_ifmedia_upd(struct ifnet *ifp)
2225{
2226	return (0);
2227}
2228
2229static void
2230xn_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr)
2231{
2232	ifmr->ifm_status = IFM_AVALID|IFM_ACTIVE;
2233	ifmr->ifm_active = IFM_ETHER|IFM_MANUAL;
2234}
2235
2236/* ** Driver registration ** */
2237static device_method_t netfront_methods[] = {
2238	/* Device interface */
2239	DEVMETHOD(device_probe,         netfront_probe),
2240	DEVMETHOD(device_attach,        netfront_attach),
2241	DEVMETHOD(device_detach,        netfront_detach),
2242	DEVMETHOD(device_shutdown,      bus_generic_shutdown),
2243	DEVMETHOD(device_suspend,       netfront_suspend),
2244	DEVMETHOD(device_resume,        netfront_resume),
2245
2246	/* Xenbus interface */
2247	DEVMETHOD(xenbus_otherend_changed, netfront_backend_changed),
2248
2249	DEVMETHOD_END
2250};
2251
2252static driver_t netfront_driver = {
2253	"xn",
2254	netfront_methods,
2255	sizeof(struct netfront_info),
2256};
2257devclass_t netfront_devclass;
2258
2259DRIVER_MODULE(xe, xenbusb_front, netfront_driver, netfront_devclass, NULL,
2260    NULL);
2261