xref: /openbmc/linux/drivers/net/hyperv/netvsc_drv.c (revision 6774def6)
1 /*
2  * Copyright (c) 2009, Microsoft Corporation.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; if not, see <http://www.gnu.org/licenses/>.
15  *
16  * Authors:
17  *   Haiyang Zhang <haiyangz@microsoft.com>
18  *   Hank Janssen  <hjanssen@microsoft.com>
19  */
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 
22 #include <linux/init.h>
23 #include <linux/atomic.h>
24 #include <linux/module.h>
25 #include <linux/highmem.h>
26 #include <linux/device.h>
27 #include <linux/io.h>
28 #include <linux/delay.h>
29 #include <linux/netdevice.h>
30 #include <linux/inetdevice.h>
31 #include <linux/etherdevice.h>
32 #include <linux/skbuff.h>
33 #include <linux/if_vlan.h>
34 #include <linux/in.h>
35 #include <linux/slab.h>
36 #include <net/arp.h>
37 #include <net/route.h>
38 #include <net/sock.h>
39 #include <net/pkt_sched.h>
40 
41 #include "hyperv_net.h"
42 
43 struct net_device_context {
44 	/* point back to our device context */
45 	struct hv_device *device_ctx;
46 	struct delayed_work dwork;
47 	struct work_struct work;
48 };
49 
50 #define RING_SIZE_MIN 64
51 static int ring_size = 128;
52 module_param(ring_size, int, S_IRUGO);
53 MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
54 
55 static void do_set_multicast(struct work_struct *w)
56 {
57 	struct net_device_context *ndevctx =
58 		container_of(w, struct net_device_context, work);
59 	struct netvsc_device *nvdev;
60 	struct rndis_device *rdev;
61 
62 	nvdev = hv_get_drvdata(ndevctx->device_ctx);
63 	if (nvdev == NULL || nvdev->ndev == NULL)
64 		return;
65 
66 	rdev = nvdev->extension;
67 	if (rdev == NULL)
68 		return;
69 
70 	if (nvdev->ndev->flags & IFF_PROMISC)
71 		rndis_filter_set_packet_filter(rdev,
72 			NDIS_PACKET_TYPE_PROMISCUOUS);
73 	else
74 		rndis_filter_set_packet_filter(rdev,
75 			NDIS_PACKET_TYPE_BROADCAST |
76 			NDIS_PACKET_TYPE_ALL_MULTICAST |
77 			NDIS_PACKET_TYPE_DIRECTED);
78 }
79 
80 static void netvsc_set_multicast_list(struct net_device *net)
81 {
82 	struct net_device_context *net_device_ctx = netdev_priv(net);
83 
84 	schedule_work(&net_device_ctx->work);
85 }
86 
87 static int netvsc_open(struct net_device *net)
88 {
89 	struct net_device_context *net_device_ctx = netdev_priv(net);
90 	struct hv_device *device_obj = net_device_ctx->device_ctx;
91 	struct netvsc_device *nvdev;
92 	struct rndis_device *rdev;
93 	int ret = 0;
94 
95 	netif_carrier_off(net);
96 
97 	/* Open up the device */
98 	ret = rndis_filter_open(device_obj);
99 	if (ret != 0) {
100 		netdev_err(net, "unable to open device (ret %d).\n", ret);
101 		return ret;
102 	}
103 
104 	netif_tx_start_all_queues(net);
105 
106 	nvdev = hv_get_drvdata(device_obj);
107 	rdev = nvdev->extension;
108 	if (!rdev->link_state)
109 		netif_carrier_on(net);
110 
111 	return ret;
112 }
113 
114 static int netvsc_close(struct net_device *net)
115 {
116 	struct net_device_context *net_device_ctx = netdev_priv(net);
117 	struct hv_device *device_obj = net_device_ctx->device_ctx;
118 	int ret;
119 
120 	netif_tx_disable(net);
121 
122 	/* Make sure netvsc_set_multicast_list doesn't re-enable filter! */
123 	cancel_work_sync(&net_device_ctx->work);
124 	ret = rndis_filter_close(device_obj);
125 	if (ret != 0)
126 		netdev_err(net, "unable to close device (ret %d).\n", ret);
127 
128 	return ret;
129 }
130 
131 static void *init_ppi_data(struct rndis_message *msg, u32 ppi_size,
132 				int pkt_type)
133 {
134 	struct rndis_packet *rndis_pkt;
135 	struct rndis_per_packet_info *ppi;
136 
137 	rndis_pkt = &msg->msg.pkt;
138 	rndis_pkt->data_offset += ppi_size;
139 
140 	ppi = (struct rndis_per_packet_info *)((void *)rndis_pkt +
141 		rndis_pkt->per_pkt_info_offset + rndis_pkt->per_pkt_info_len);
142 
143 	ppi->size = ppi_size;
144 	ppi->type = pkt_type;
145 	ppi->ppi_offset = sizeof(struct rndis_per_packet_info);
146 
147 	rndis_pkt->per_pkt_info_len += ppi_size;
148 
149 	return ppi;
150 }
151 
152 union sub_key {
153 	u64 k;
154 	struct {
155 		u8 pad[3];
156 		u8 kb;
157 		u32 ka;
158 	};
159 };
160 
161 /* Toeplitz hash function
162  * data: network byte order
163  * return: host byte order
164  */
165 static u32 comp_hash(u8 *key, int klen, void *data, int dlen)
166 {
167 	union sub_key subk;
168 	int k_next = 4;
169 	u8 dt;
170 	int i, j;
171 	u32 ret = 0;
172 
173 	subk.k = 0;
174 	subk.ka = ntohl(*(u32 *)key);
175 
176 	for (i = 0; i < dlen; i++) {
177 		subk.kb = key[k_next];
178 		k_next = (k_next + 1) % klen;
179 		dt = ((u8 *)data)[i];
180 		for (j = 0; j < 8; j++) {
181 			if (dt & 0x80)
182 				ret ^= subk.ka;
183 			dt <<= 1;
184 			subk.k <<= 1;
185 		}
186 	}
187 
188 	return ret;
189 }
190 
191 static bool netvsc_set_hash(u32 *hash, struct sk_buff *skb)
192 {
193 	struct flow_keys flow;
194 	int data_len;
195 
196 	if (!skb_flow_dissect(skb, &flow) || flow.n_proto != htons(ETH_P_IP))
197 		return false;
198 
199 	if (flow.ip_proto == IPPROTO_TCP)
200 		data_len = 12;
201 	else
202 		data_len = 8;
203 
204 	*hash = comp_hash(netvsc_hash_key, HASH_KEYLEN, &flow, data_len);
205 
206 	return true;
207 }
208 
209 static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
210 			void *accel_priv, select_queue_fallback_t fallback)
211 {
212 	struct net_device_context *net_device_ctx = netdev_priv(ndev);
213 	struct hv_device *hdev =  net_device_ctx->device_ctx;
214 	struct netvsc_device *nvsc_dev = hv_get_drvdata(hdev);
215 	u32 hash;
216 	u16 q_idx = 0;
217 
218 	if (nvsc_dev == NULL || ndev->real_num_tx_queues <= 1)
219 		return 0;
220 
221 	if (netvsc_set_hash(&hash, skb)) {
222 		q_idx = nvsc_dev->send_table[hash % VRSS_SEND_TAB_SIZE] %
223 			ndev->real_num_tx_queues;
224 		skb_set_hash(skb, hash, PKT_HASH_TYPE_L3);
225 	}
226 
227 	return q_idx;
228 }
229 
230 static void netvsc_xmit_completion(void *context)
231 {
232 	struct hv_netvsc_packet *packet = (struct hv_netvsc_packet *)context;
233 	struct sk_buff *skb = (struct sk_buff *)
234 		(unsigned long)packet->send_completion_tid;
235 	u32 index = packet->send_buf_index;
236 
237 	kfree(packet);
238 
239 	if (skb && (index == NETVSC_INVALID_INDEX))
240 		dev_kfree_skb_any(skb);
241 }
242 
243 static u32 fill_pg_buf(struct page *page, u32 offset, u32 len,
244 			struct hv_page_buffer *pb)
245 {
246 	int j = 0;
247 
248 	/* Deal with compund pages by ignoring unused part
249 	 * of the page.
250 	 */
251 	page += (offset >> PAGE_SHIFT);
252 	offset &= ~PAGE_MASK;
253 
254 	while (len > 0) {
255 		unsigned long bytes;
256 
257 		bytes = PAGE_SIZE - offset;
258 		if (bytes > len)
259 			bytes = len;
260 		pb[j].pfn = page_to_pfn(page);
261 		pb[j].offset = offset;
262 		pb[j].len = bytes;
263 
264 		offset += bytes;
265 		len -= bytes;
266 
267 		if (offset == PAGE_SIZE && len) {
268 			page++;
269 			offset = 0;
270 			j++;
271 		}
272 	}
273 
274 	return j + 1;
275 }
276 
277 static u32 init_page_array(void *hdr, u32 len, struct sk_buff *skb,
278 			   struct hv_page_buffer *pb)
279 {
280 	u32 slots_used = 0;
281 	char *data = skb->data;
282 	int frags = skb_shinfo(skb)->nr_frags;
283 	int i;
284 
285 	/* The packet is laid out thus:
286 	 * 1. hdr
287 	 * 2. skb linear data
288 	 * 3. skb fragment data
289 	 */
290 	if (hdr != NULL)
291 		slots_used += fill_pg_buf(virt_to_page(hdr),
292 					offset_in_page(hdr),
293 					len, &pb[slots_used]);
294 
295 	slots_used += fill_pg_buf(virt_to_page(data),
296 				offset_in_page(data),
297 				skb_headlen(skb), &pb[slots_used]);
298 
299 	for (i = 0; i < frags; i++) {
300 		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
301 
302 		slots_used += fill_pg_buf(skb_frag_page(frag),
303 					frag->page_offset,
304 					skb_frag_size(frag), &pb[slots_used]);
305 	}
306 	return slots_used;
307 }
308 
309 static int count_skb_frag_slots(struct sk_buff *skb)
310 {
311 	int i, frags = skb_shinfo(skb)->nr_frags;
312 	int pages = 0;
313 
314 	for (i = 0; i < frags; i++) {
315 		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
316 		unsigned long size = skb_frag_size(frag);
317 		unsigned long offset = frag->page_offset;
318 
319 		/* Skip unused frames from start of page */
320 		offset &= ~PAGE_MASK;
321 		pages += PFN_UP(offset + size);
322 	}
323 	return pages;
324 }
325 
326 static int netvsc_get_slots(struct sk_buff *skb)
327 {
328 	char *data = skb->data;
329 	unsigned int offset = offset_in_page(data);
330 	unsigned int len = skb_headlen(skb);
331 	int slots;
332 	int frag_slots;
333 
334 	slots = DIV_ROUND_UP(offset + len, PAGE_SIZE);
335 	frag_slots = count_skb_frag_slots(skb);
336 	return slots + frag_slots;
337 }
338 
339 static u32 get_net_transport_info(struct sk_buff *skb, u32 *trans_off)
340 {
341 	u32 ret_val = TRANSPORT_INFO_NOT_IP;
342 
343 	if ((eth_hdr(skb)->h_proto != htons(ETH_P_IP)) &&
344 		(eth_hdr(skb)->h_proto != htons(ETH_P_IPV6))) {
345 		goto not_ip;
346 	}
347 
348 	*trans_off = skb_transport_offset(skb);
349 
350 	if ((eth_hdr(skb)->h_proto == htons(ETH_P_IP))) {
351 		struct iphdr *iphdr = ip_hdr(skb);
352 
353 		if (iphdr->protocol == IPPROTO_TCP)
354 			ret_val = TRANSPORT_INFO_IPV4_TCP;
355 		else if (iphdr->protocol == IPPROTO_UDP)
356 			ret_val = TRANSPORT_INFO_IPV4_UDP;
357 	} else {
358 		if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
359 			ret_val = TRANSPORT_INFO_IPV6_TCP;
360 		else if (ipv6_hdr(skb)->nexthdr == IPPROTO_UDP)
361 			ret_val = TRANSPORT_INFO_IPV6_UDP;
362 	}
363 
364 not_ip:
365 	return ret_val;
366 }
367 
368 static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
369 {
370 	struct net_device_context *net_device_ctx = netdev_priv(net);
371 	struct hv_netvsc_packet *packet;
372 	int ret;
373 	unsigned int num_data_pgs;
374 	struct rndis_message *rndis_msg;
375 	struct rndis_packet *rndis_pkt;
376 	u32 rndis_msg_size;
377 	bool isvlan;
378 	struct rndis_per_packet_info *ppi;
379 	struct ndis_tcp_ip_checksum_info *csum_info;
380 	struct ndis_tcp_lso_info *lso_info;
381 	int  hdr_offset;
382 	u32 net_trans_info;
383 	u32 hash;
384 	u32 skb_length = skb->len;
385 
386 
387 	/* We will atmost need two pages to describe the rndis
388 	 * header. We can only transmit MAX_PAGE_BUFFER_COUNT number
389 	 * of pages in a single packet.
390 	 */
391 	num_data_pgs = netvsc_get_slots(skb) + 2;
392 	if (num_data_pgs > MAX_PAGE_BUFFER_COUNT) {
393 		netdev_err(net, "Packet too big: %u\n", skb->len);
394 		dev_kfree_skb(skb);
395 		net->stats.tx_dropped++;
396 		return NETDEV_TX_OK;
397 	}
398 
399 	/* Allocate a netvsc packet based on # of frags. */
400 	packet = kzalloc(sizeof(struct hv_netvsc_packet) +
401 			 (num_data_pgs * sizeof(struct hv_page_buffer)) +
402 			 sizeof(struct rndis_message) +
403 			 NDIS_VLAN_PPI_SIZE + NDIS_CSUM_PPI_SIZE +
404 			 NDIS_LSO_PPI_SIZE + NDIS_HASH_PPI_SIZE, GFP_ATOMIC);
405 	if (!packet) {
406 		/* out of memory, drop packet */
407 		netdev_err(net, "unable to allocate hv_netvsc_packet\n");
408 
409 		dev_kfree_skb(skb);
410 		net->stats.tx_dropped++;
411 		return NETDEV_TX_OK;
412 	}
413 
414 	packet->vlan_tci = skb->vlan_tci;
415 
416 	packet->q_idx = skb_get_queue_mapping(skb);
417 
418 	packet->is_data_pkt = true;
419 	packet->total_data_buflen = skb->len;
420 
421 	packet->rndis_msg = (struct rndis_message *)((unsigned long)packet +
422 				sizeof(struct hv_netvsc_packet) +
423 				(num_data_pgs * sizeof(struct hv_page_buffer)));
424 
425 	/* Set the completion routine */
426 	packet->send_completion = netvsc_xmit_completion;
427 	packet->send_completion_ctx = packet;
428 	packet->send_completion_tid = (unsigned long)skb;
429 
430 	isvlan = packet->vlan_tci & VLAN_TAG_PRESENT;
431 
432 	/* Add the rndis header */
433 	rndis_msg = packet->rndis_msg;
434 	rndis_msg->ndis_msg_type = RNDIS_MSG_PACKET;
435 	rndis_msg->msg_len = packet->total_data_buflen;
436 	rndis_pkt = &rndis_msg->msg.pkt;
437 	rndis_pkt->data_offset = sizeof(struct rndis_packet);
438 	rndis_pkt->data_len = packet->total_data_buflen;
439 	rndis_pkt->per_pkt_info_offset = sizeof(struct rndis_packet);
440 
441 	rndis_msg_size = RNDIS_MESSAGE_SIZE(struct rndis_packet);
442 
443 	hash = skb_get_hash_raw(skb);
444 	if (hash != 0 && net->real_num_tx_queues > 1) {
445 		rndis_msg_size += NDIS_HASH_PPI_SIZE;
446 		ppi = init_ppi_data(rndis_msg, NDIS_HASH_PPI_SIZE,
447 				    NBL_HASH_VALUE);
448 		*(u32 *)((void *)ppi + ppi->ppi_offset) = hash;
449 	}
450 
451 	if (isvlan) {
452 		struct ndis_pkt_8021q_info *vlan;
453 
454 		rndis_msg_size += NDIS_VLAN_PPI_SIZE;
455 		ppi = init_ppi_data(rndis_msg, NDIS_VLAN_PPI_SIZE,
456 					IEEE_8021Q_INFO);
457 		vlan = (struct ndis_pkt_8021q_info *)((void *)ppi +
458 						ppi->ppi_offset);
459 		vlan->vlanid = packet->vlan_tci & VLAN_VID_MASK;
460 		vlan->pri = (packet->vlan_tci & VLAN_PRIO_MASK) >>
461 				VLAN_PRIO_SHIFT;
462 	}
463 
464 	net_trans_info = get_net_transport_info(skb, &hdr_offset);
465 	if (net_trans_info == TRANSPORT_INFO_NOT_IP)
466 		goto do_send;
467 
468 	/*
469 	 * Setup the sendside checksum offload only if this is not a
470 	 * GSO packet.
471 	 */
472 	if (skb_is_gso(skb))
473 		goto do_lso;
474 
475 	if ((skb->ip_summed == CHECKSUM_NONE) ||
476 	    (skb->ip_summed == CHECKSUM_UNNECESSARY))
477 		goto do_send;
478 
479 	rndis_msg_size += NDIS_CSUM_PPI_SIZE;
480 	ppi = init_ppi_data(rndis_msg, NDIS_CSUM_PPI_SIZE,
481 			    TCPIP_CHKSUM_PKTINFO);
482 
483 	csum_info = (struct ndis_tcp_ip_checksum_info *)((void *)ppi +
484 			ppi->ppi_offset);
485 
486 	if (net_trans_info & (INFO_IPV4 << 16))
487 		csum_info->transmit.is_ipv4 = 1;
488 	else
489 		csum_info->transmit.is_ipv6 = 1;
490 
491 	if (net_trans_info & INFO_TCP) {
492 		csum_info->transmit.tcp_checksum = 1;
493 		csum_info->transmit.tcp_header_offset = hdr_offset;
494 	} else if (net_trans_info & INFO_UDP) {
495 		/* UDP checksum offload is not supported on ws2008r2.
496 		 * Furthermore, on ws2012 and ws2012r2, there are some
497 		 * issues with udp checksum offload from Linux guests.
498 		 * (these are host issues).
499 		 * For now compute the checksum here.
500 		 */
501 		struct udphdr *uh;
502 		u16 udp_len;
503 
504 		ret = skb_cow_head(skb, 0);
505 		if (ret)
506 			goto drop;
507 
508 		uh = udp_hdr(skb);
509 		udp_len = ntohs(uh->len);
510 		uh->check = 0;
511 		uh->check = csum_tcpudp_magic(ip_hdr(skb)->saddr,
512 					      ip_hdr(skb)->daddr,
513 					      udp_len, IPPROTO_UDP,
514 					      csum_partial(uh, udp_len, 0));
515 		if (uh->check == 0)
516 			uh->check = CSUM_MANGLED_0;
517 
518 		csum_info->transmit.udp_checksum = 0;
519 	}
520 	goto do_send;
521 
522 do_lso:
523 	rndis_msg_size += NDIS_LSO_PPI_SIZE;
524 	ppi = init_ppi_data(rndis_msg, NDIS_LSO_PPI_SIZE,
525 			    TCP_LARGESEND_PKTINFO);
526 
527 	lso_info = (struct ndis_tcp_lso_info *)((void *)ppi +
528 			ppi->ppi_offset);
529 
530 	lso_info->lso_v2_transmit.type = NDIS_TCP_LARGE_SEND_OFFLOAD_V2_TYPE;
531 	if (net_trans_info & (INFO_IPV4 << 16)) {
532 		lso_info->lso_v2_transmit.ip_version =
533 			NDIS_TCP_LARGE_SEND_OFFLOAD_IPV4;
534 		ip_hdr(skb)->tot_len = 0;
535 		ip_hdr(skb)->check = 0;
536 		tcp_hdr(skb)->check =
537 		~csum_tcpudp_magic(ip_hdr(skb)->saddr,
538 				   ip_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
539 	} else {
540 		lso_info->lso_v2_transmit.ip_version =
541 			NDIS_TCP_LARGE_SEND_OFFLOAD_IPV6;
542 		ipv6_hdr(skb)->payload_len = 0;
543 		tcp_hdr(skb)->check =
544 		~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
545 				&ipv6_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
546 	}
547 	lso_info->lso_v2_transmit.tcp_header_offset = hdr_offset;
548 	lso_info->lso_v2_transmit.mss = skb_shinfo(skb)->gso_size;
549 
550 do_send:
551 	/* Start filling in the page buffers with the rndis hdr */
552 	rndis_msg->msg_len += rndis_msg_size;
553 	packet->total_data_buflen = rndis_msg->msg_len;
554 	packet->page_buf_cnt = init_page_array(rndis_msg, rndis_msg_size,
555 					skb, &packet->page_buf[0]);
556 
557 	ret = netvsc_send(net_device_ctx->device_ctx, packet);
558 
559 drop:
560 	if (ret == 0) {
561 		net->stats.tx_bytes += skb_length;
562 		net->stats.tx_packets++;
563 	} else {
564 		kfree(packet);
565 		if (ret != -EAGAIN) {
566 			dev_kfree_skb_any(skb);
567 			net->stats.tx_dropped++;
568 		}
569 	}
570 
571 	return (ret == -EAGAIN) ? NETDEV_TX_BUSY : NETDEV_TX_OK;
572 }
573 
574 /*
575  * netvsc_linkstatus_callback - Link up/down notification
576  */
577 void netvsc_linkstatus_callback(struct hv_device *device_obj,
578 				struct rndis_message *resp)
579 {
580 	struct rndis_indicate_status *indicate = &resp->msg.indicate_status;
581 	struct net_device *net;
582 	struct net_device_context *ndev_ctx;
583 	struct netvsc_device *net_device;
584 	struct rndis_device *rdev;
585 
586 	net_device = hv_get_drvdata(device_obj);
587 	rdev = net_device->extension;
588 
589 	switch (indicate->status) {
590 	case RNDIS_STATUS_MEDIA_CONNECT:
591 		rdev->link_state = false;
592 		break;
593 	case RNDIS_STATUS_MEDIA_DISCONNECT:
594 		rdev->link_state = true;
595 		break;
596 	case RNDIS_STATUS_NETWORK_CHANGE:
597 		rdev->link_change = true;
598 		break;
599 	default:
600 		return;
601 	}
602 
603 	net = net_device->ndev;
604 
605 	if (!net || net->reg_state != NETREG_REGISTERED)
606 		return;
607 
608 	ndev_ctx = netdev_priv(net);
609 	if (!rdev->link_state) {
610 		schedule_delayed_work(&ndev_ctx->dwork, 0);
611 		schedule_delayed_work(&ndev_ctx->dwork, msecs_to_jiffies(20));
612 	} else {
613 		schedule_delayed_work(&ndev_ctx->dwork, 0);
614 	}
615 }
616 
617 /*
618  * netvsc_recv_callback -  Callback when we receive a packet from the
619  * "wire" on the specified device.
620  */
621 int netvsc_recv_callback(struct hv_device *device_obj,
622 				struct hv_netvsc_packet *packet,
623 				struct ndis_tcp_ip_checksum_info *csum_info)
624 {
625 	struct net_device *net;
626 	struct sk_buff *skb;
627 
628 	net = ((struct netvsc_device *)hv_get_drvdata(device_obj))->ndev;
629 	if (!net || net->reg_state != NETREG_REGISTERED) {
630 		packet->status = NVSP_STAT_FAIL;
631 		return 0;
632 	}
633 
634 	/* Allocate a skb - TODO direct I/O to pages? */
635 	skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
636 	if (unlikely(!skb)) {
637 		++net->stats.rx_dropped;
638 		packet->status = NVSP_STAT_FAIL;
639 		return 0;
640 	}
641 
642 	/*
643 	 * Copy to skb. This copy is needed here since the memory pointed by
644 	 * hv_netvsc_packet cannot be deallocated
645 	 */
646 	memcpy(skb_put(skb, packet->total_data_buflen), packet->data,
647 		packet->total_data_buflen);
648 
649 	skb->protocol = eth_type_trans(skb, net);
650 	if (csum_info) {
651 		/* We only look at the IP checksum here.
652 		 * Should we be dropping the packet if checksum
653 		 * failed? How do we deal with other checksums - TCP/UDP?
654 		 */
655 		if (csum_info->receive.ip_checksum_succeeded)
656 			skb->ip_summed = CHECKSUM_UNNECESSARY;
657 		else
658 			skb->ip_summed = CHECKSUM_NONE;
659 	}
660 
661 	if (packet->vlan_tci & VLAN_TAG_PRESENT)
662 		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
663 				       packet->vlan_tci);
664 
665 	skb_record_rx_queue(skb, packet->channel->
666 			    offermsg.offer.sub_channel_index);
667 
668 	net->stats.rx_packets++;
669 	net->stats.rx_bytes += packet->total_data_buflen;
670 
671 	/*
672 	 * Pass the skb back up. Network stack will deallocate the skb when it
673 	 * is done.
674 	 * TODO - use NAPI?
675 	 */
676 	netif_rx(skb);
677 
678 	return 0;
679 }
680 
681 static void netvsc_get_drvinfo(struct net_device *net,
682 			       struct ethtool_drvinfo *info)
683 {
684 	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
685 	strlcpy(info->fw_version, "N/A", sizeof(info->fw_version));
686 }
687 
688 static int netvsc_change_mtu(struct net_device *ndev, int mtu)
689 {
690 	struct net_device_context *ndevctx = netdev_priv(ndev);
691 	struct hv_device *hdev =  ndevctx->device_ctx;
692 	struct netvsc_device *nvdev = hv_get_drvdata(hdev);
693 	struct netvsc_device_info device_info;
694 	int limit = ETH_DATA_LEN;
695 
696 	if (nvdev == NULL || nvdev->destroy)
697 		return -ENODEV;
698 
699 	if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)
700 		limit = NETVSC_MTU;
701 
702 	if (mtu < 68 || mtu > limit)
703 		return -EINVAL;
704 
705 	nvdev->start_remove = true;
706 	cancel_work_sync(&ndevctx->work);
707 	netif_tx_disable(ndev);
708 	rndis_filter_device_remove(hdev);
709 
710 	ndev->mtu = mtu;
711 
712 	ndevctx->device_ctx = hdev;
713 	hv_set_drvdata(hdev, ndev);
714 	device_info.ring_size = ring_size;
715 	rndis_filter_device_add(hdev, &device_info);
716 	netif_tx_wake_all_queues(ndev);
717 
718 	return 0;
719 }
720 
721 
722 static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
723 {
724 	struct net_device_context *ndevctx = netdev_priv(ndev);
725 	struct hv_device *hdev =  ndevctx->device_ctx;
726 	struct sockaddr *addr = p;
727 	char save_adr[ETH_ALEN];
728 	unsigned char save_aatype;
729 	int err;
730 
731 	memcpy(save_adr, ndev->dev_addr, ETH_ALEN);
732 	save_aatype = ndev->addr_assign_type;
733 
734 	err = eth_mac_addr(ndev, p);
735 	if (err != 0)
736 		return err;
737 
738 	err = rndis_filter_set_device_mac(hdev, addr->sa_data);
739 	if (err != 0) {
740 		/* roll back to saved MAC */
741 		memcpy(ndev->dev_addr, save_adr, ETH_ALEN);
742 		ndev->addr_assign_type = save_aatype;
743 	}
744 
745 	return err;
746 }
747 
748 #ifdef CONFIG_NET_POLL_CONTROLLER
749 static void netvsc_poll_controller(struct net_device *net)
750 {
751 	/* As netvsc_start_xmit() works synchronous we don't have to
752 	 * trigger anything here.
753 	 */
754 }
755 #endif
756 
757 static const struct ethtool_ops ethtool_ops = {
758 	.get_drvinfo	= netvsc_get_drvinfo,
759 	.get_link	= ethtool_op_get_link,
760 };
761 
762 static const struct net_device_ops device_ops = {
763 	.ndo_open =			netvsc_open,
764 	.ndo_stop =			netvsc_close,
765 	.ndo_start_xmit =		netvsc_start_xmit,
766 	.ndo_set_rx_mode =		netvsc_set_multicast_list,
767 	.ndo_change_mtu =		netvsc_change_mtu,
768 	.ndo_validate_addr =		eth_validate_addr,
769 	.ndo_set_mac_address =		netvsc_set_mac_addr,
770 	.ndo_select_queue =		netvsc_select_queue,
771 #ifdef CONFIG_NET_POLL_CONTROLLER
772 	.ndo_poll_controller =		netvsc_poll_controller,
773 #endif
774 };
775 
776 /*
777  * Send GARP packet to network peers after migrations.
778  * After Quick Migration, the network is not immediately operational in the
779  * current context when receiving RNDIS_STATUS_MEDIA_CONNECT event. So, add
780  * another netif_notify_peers() into a delayed work, otherwise GARP packet
781  * will not be sent after quick migration, and cause network disconnection.
782  * Also, we update the carrier status here.
783  */
784 static void netvsc_link_change(struct work_struct *w)
785 {
786 	struct net_device_context *ndev_ctx;
787 	struct net_device *net;
788 	struct netvsc_device *net_device;
789 	struct rndis_device *rdev;
790 	bool notify, refresh = false;
791 	char *argv[] = { "/etc/init.d/network", "restart", NULL };
792 	char *envp[] = { "HOME=/", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
793 
794 	rtnl_lock();
795 
796 	ndev_ctx = container_of(w, struct net_device_context, dwork.work);
797 	net_device = hv_get_drvdata(ndev_ctx->device_ctx);
798 	rdev = net_device->extension;
799 	net = net_device->ndev;
800 
801 	if (rdev->link_state) {
802 		netif_carrier_off(net);
803 		notify = false;
804 	} else {
805 		netif_carrier_on(net);
806 		notify = true;
807 		if (rdev->link_change) {
808 			rdev->link_change = false;
809 			refresh = true;
810 		}
811 	}
812 
813 	rtnl_unlock();
814 
815 	if (refresh)
816 		call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
817 
818 	if (notify)
819 		netdev_notify_peers(net);
820 }
821 
822 
823 static int netvsc_probe(struct hv_device *dev,
824 			const struct hv_vmbus_device_id *dev_id)
825 {
826 	struct net_device *net = NULL;
827 	struct net_device_context *net_device_ctx;
828 	struct netvsc_device_info device_info;
829 	struct netvsc_device *nvdev;
830 	int ret;
831 
832 	net = alloc_etherdev_mq(sizeof(struct net_device_context),
833 				num_online_cpus());
834 	if (!net)
835 		return -ENOMEM;
836 
837 	netif_carrier_off(net);
838 
839 	net_device_ctx = netdev_priv(net);
840 	net_device_ctx->device_ctx = dev;
841 	hv_set_drvdata(dev, net);
842 	INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
843 	INIT_WORK(&net_device_ctx->work, do_set_multicast);
844 
845 	net->netdev_ops = &device_ops;
846 
847 	net->hw_features = NETIF_F_RXCSUM | NETIF_F_SG | NETIF_F_IP_CSUM |
848 				NETIF_F_TSO;
849 	net->features = NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_SG | NETIF_F_RXCSUM |
850 			NETIF_F_IP_CSUM | NETIF_F_TSO;
851 
852 	net->ethtool_ops = &ethtool_ops;
853 	SET_NETDEV_DEV(net, &dev->device);
854 
855 	/* Notify the netvsc driver of the new device */
856 	device_info.ring_size = ring_size;
857 	ret = rndis_filter_device_add(dev, &device_info);
858 	if (ret != 0) {
859 		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
860 		free_netdev(net);
861 		hv_set_drvdata(dev, NULL);
862 		return ret;
863 	}
864 	memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);
865 
866 	nvdev = hv_get_drvdata(dev);
867 	netif_set_real_num_tx_queues(net, nvdev->num_chn);
868 	netif_set_real_num_rx_queues(net, nvdev->num_chn);
869 
870 	ret = register_netdev(net);
871 	if (ret != 0) {
872 		pr_err("Unable to register netdev.\n");
873 		rndis_filter_device_remove(dev);
874 		free_netdev(net);
875 	} else {
876 		schedule_delayed_work(&net_device_ctx->dwork, 0);
877 	}
878 
879 	return ret;
880 }
881 
882 static int netvsc_remove(struct hv_device *dev)
883 {
884 	struct net_device *net;
885 	struct net_device_context *ndev_ctx;
886 	struct netvsc_device *net_device;
887 
888 	net_device = hv_get_drvdata(dev);
889 	net = net_device->ndev;
890 
891 	if (net == NULL) {
892 		dev_err(&dev->device, "No net device to remove\n");
893 		return 0;
894 	}
895 
896 	net_device->start_remove = true;
897 
898 	ndev_ctx = netdev_priv(net);
899 	cancel_delayed_work_sync(&ndev_ctx->dwork);
900 	cancel_work_sync(&ndev_ctx->work);
901 
902 	/* Stop outbound asap */
903 	netif_tx_disable(net);
904 
905 	unregister_netdev(net);
906 
907 	/*
908 	 * Call to the vsc driver to let it know that the device is being
909 	 * removed
910 	 */
911 	rndis_filter_device_remove(dev);
912 
913 	free_netdev(net);
914 	return 0;
915 }
916 
917 static const struct hv_vmbus_device_id id_table[] = {
918 	/* Network guid */
919 	{ HV_NIC_GUID, },
920 	{ },
921 };
922 
923 MODULE_DEVICE_TABLE(vmbus, id_table);
924 
925 /* The one and only one */
926 static struct  hv_driver netvsc_drv = {
927 	.name = KBUILD_MODNAME,
928 	.id_table = id_table,
929 	.probe = netvsc_probe,
930 	.remove = netvsc_remove,
931 };
932 
933 static void __exit netvsc_drv_exit(void)
934 {
935 	vmbus_driver_unregister(&netvsc_drv);
936 }
937 
938 static int __init netvsc_drv_init(void)
939 {
940 	if (ring_size < RING_SIZE_MIN) {
941 		ring_size = RING_SIZE_MIN;
942 		pr_info("Increased ring_size to %d (min allowed)\n",
943 			ring_size);
944 	}
945 	return vmbus_driver_register(&netvsc_drv);
946 }
947 
948 MODULE_LICENSE("GPL");
949 MODULE_DESCRIPTION("Microsoft Hyper-V network driver");
950 
951 module_init(netvsc_drv_init);
952 module_exit(netvsc_drv_exit);
953