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[mirror_ubuntu-bionic-kernel.git] / net / core / netpoll.c
1 /*
2 * Common framework for low-level network console, dump, and debugger code
3 *
4 * Sep 8 2003 Matt Mackall <mpm@selenic.com>
5 *
6 * based on the netconsole code from:
7 *
8 * Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
9 * Copyright (C) 2002 Red Hat, Inc.
10 */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/moduleparam.h>
15 #include <linux/netdevice.h>
16 #include <linux/etherdevice.h>
17 #include <linux/string.h>
18 #include <linux/if_arp.h>
19 #include <linux/inetdevice.h>
20 #include <linux/inet.h>
21 #include <linux/interrupt.h>
22 #include <linux/netpoll.h>
23 #include <linux/sched.h>
24 #include <linux/delay.h>
25 #include <linux/rcupdate.h>
26 #include <linux/workqueue.h>
27 #include <linux/slab.h>
28 #include <linux/export.h>
29 #include <linux/if_vlan.h>
30 #include <net/tcp.h>
31 #include <net/udp.h>
32 #include <net/addrconf.h>
33 #include <net/ndisc.h>
34 #include <net/ip6_checksum.h>
35 #include <asm/unaligned.h>
36 #include <trace/events/napi.h>
37
38 /*
39 * We maintain a small pool of fully-sized skbs, to make sure the
40 * message gets out even in extreme OOM situations.
41 */
42
43 #define MAX_UDP_CHUNK 1460
44 #define MAX_SKBS 32
45
46 static struct sk_buff_head skb_pool;
47
48 static atomic_t trapped;
49
50 DEFINE_STATIC_SRCU(netpoll_srcu);
51
52 #define USEC_PER_POLL 50
53 #define NETPOLL_RX_ENABLED 1
54 #define NETPOLL_RX_DROP 2
55
56 #define MAX_SKB_SIZE \
57 (sizeof(struct ethhdr) + \
58 sizeof(struct iphdr) + \
59 sizeof(struct udphdr) + \
60 MAX_UDP_CHUNK)
61
62 static void zap_completion_queue(void);
63 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo);
64 static void netpoll_async_cleanup(struct work_struct *work);
65
66 static unsigned int carrier_timeout = 4;
67 module_param(carrier_timeout, uint, 0644);
68
69 #define np_info(np, fmt, ...) \
70 pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
71 #define np_err(np, fmt, ...) \
72 pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
73 #define np_notice(np, fmt, ...) \
74 pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
75
76 static void queue_process(struct work_struct *work)
77 {
78 struct netpoll_info *npinfo =
79 container_of(work, struct netpoll_info, tx_work.work);
80 struct sk_buff *skb;
81 unsigned long flags;
82
83 while ((skb = skb_dequeue(&npinfo->txq))) {
84 struct net_device *dev = skb->dev;
85 const struct net_device_ops *ops = dev->netdev_ops;
86 struct netdev_queue *txq;
87
88 if (!netif_device_present(dev) || !netif_running(dev)) {
89 __kfree_skb(skb);
90 continue;
91 }
92
93 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
94
95 local_irq_save(flags);
96 __netif_tx_lock(txq, smp_processor_id());
97 if (netif_xmit_frozen_or_stopped(txq) ||
98 ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
99 skb_queue_head(&npinfo->txq, skb);
100 __netif_tx_unlock(txq);
101 local_irq_restore(flags);
102
103 schedule_delayed_work(&npinfo->tx_work, HZ/10);
104 return;
105 }
106 __netif_tx_unlock(txq);
107 local_irq_restore(flags);
108 }
109 }
110
111 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
112 unsigned short ulen, __be32 saddr, __be32 daddr)
113 {
114 __wsum psum;
115
116 if (uh->check == 0 || skb_csum_unnecessary(skb))
117 return 0;
118
119 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
120
121 if (skb->ip_summed == CHECKSUM_COMPLETE &&
122 !csum_fold(csum_add(psum, skb->csum)))
123 return 0;
124
125 skb->csum = psum;
126
127 return __skb_checksum_complete(skb);
128 }
129
130 /*
131 * Check whether delayed processing was scheduled for our NIC. If so,
132 * we attempt to grab the poll lock and use ->poll() to pump the card.
133 * If this fails, either we've recursed in ->poll() or it's already
134 * running on another CPU.
135 *
136 * Note: we don't mask interrupts with this lock because we're using
137 * trylock here and interrupts are already disabled in the softirq
138 * case. Further, we test the poll_owner to avoid recursion on UP
139 * systems where the lock doesn't exist.
140 *
141 * In cases where there is bi-directional communications, reading only
142 * one message at a time can lead to packets being dropped by the
143 * network adapter, forcing superfluous retries and possibly timeouts.
144 * Thus, we set our budget to greater than 1.
145 */
146 static int poll_one_napi(struct netpoll_info *npinfo,
147 struct napi_struct *napi, int budget)
148 {
149 int work;
150
151 /* net_rx_action's ->poll() invocations and our's are
152 * synchronized by this test which is only made while
153 * holding the napi->poll_lock.
154 */
155 if (!test_bit(NAPI_STATE_SCHED, &napi->state))
156 return budget;
157
158 npinfo->rx_flags |= NETPOLL_RX_DROP;
159 atomic_inc(&trapped);
160 set_bit(NAPI_STATE_NPSVC, &napi->state);
161
162 work = napi->poll(napi, budget);
163 trace_napi_poll(napi);
164
165 clear_bit(NAPI_STATE_NPSVC, &napi->state);
166 atomic_dec(&trapped);
167 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
168
169 return budget - work;
170 }
171
172 static void poll_napi(struct net_device *dev)
173 {
174 struct napi_struct *napi;
175 int budget = 16;
176
177 list_for_each_entry(napi, &dev->napi_list, dev_list) {
178 if (napi->poll_owner != smp_processor_id() &&
179 spin_trylock(&napi->poll_lock)) {
180 budget = poll_one_napi(rcu_dereference_bh(dev->npinfo),
181 napi, budget);
182 spin_unlock(&napi->poll_lock);
183
184 if (!budget)
185 break;
186 }
187 }
188 }
189
190 static void service_neigh_queue(struct netpoll_info *npi)
191 {
192 if (npi) {
193 struct sk_buff *skb;
194
195 while ((skb = skb_dequeue(&npi->neigh_tx)))
196 netpoll_neigh_reply(skb, npi);
197 }
198 }
199
200 static void netpoll_poll_dev(struct net_device *dev)
201 {
202 const struct net_device_ops *ops;
203 struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
204
205 /* Don't do any rx activity if the dev_lock mutex is held
206 * the dev_open/close paths use this to block netpoll activity
207 * while changing device state
208 */
209 if (!mutex_trylock(&ni->dev_lock))
210 return;
211
212 if (!netif_running(dev)) {
213 mutex_unlock(&ni->dev_lock);
214 return;
215 }
216
217 ops = dev->netdev_ops;
218 if (!ops->ndo_poll_controller) {
219 mutex_unlock(&ni->dev_lock);
220 return;
221 }
222
223 /* Process pending work on NIC */
224 ops->ndo_poll_controller(dev);
225
226 poll_napi(dev);
227
228 mutex_unlock(&ni->dev_lock);
229
230 if (dev->flags & IFF_SLAVE) {
231 if (ni) {
232 struct net_device *bond_dev;
233 struct sk_buff *skb;
234 struct netpoll_info *bond_ni;
235
236 bond_dev = netdev_master_upper_dev_get_rcu(dev);
237 bond_ni = rcu_dereference_bh(bond_dev->npinfo);
238 while ((skb = skb_dequeue(&ni->neigh_tx))) {
239 skb->dev = bond_dev;
240 skb_queue_tail(&bond_ni->neigh_tx, skb);
241 }
242 }
243 }
244
245 service_neigh_queue(ni);
246
247 zap_completion_queue();
248 }
249
250 int netpoll_rx_disable(struct net_device *dev)
251 {
252 struct netpoll_info *ni;
253 int idx;
254 might_sleep();
255 idx = srcu_read_lock(&netpoll_srcu);
256 ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
257 if (ni)
258 mutex_lock(&ni->dev_lock);
259 srcu_read_unlock(&netpoll_srcu, idx);
260 return 0;
261 }
262 EXPORT_SYMBOL(netpoll_rx_disable);
263
264 void netpoll_rx_enable(struct net_device *dev)
265 {
266 struct netpoll_info *ni;
267 rcu_read_lock();
268 ni = rcu_dereference(dev->npinfo);
269 if (ni)
270 mutex_unlock(&ni->dev_lock);
271 rcu_read_unlock();
272 }
273 EXPORT_SYMBOL(netpoll_rx_enable);
274
275 static void refill_skbs(void)
276 {
277 struct sk_buff *skb;
278 unsigned long flags;
279
280 spin_lock_irqsave(&skb_pool.lock, flags);
281 while (skb_pool.qlen < MAX_SKBS) {
282 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
283 if (!skb)
284 break;
285
286 __skb_queue_tail(&skb_pool, skb);
287 }
288 spin_unlock_irqrestore(&skb_pool.lock, flags);
289 }
290
291 static void zap_completion_queue(void)
292 {
293 unsigned long flags;
294 struct softnet_data *sd = &get_cpu_var(softnet_data);
295
296 if (sd->completion_queue) {
297 struct sk_buff *clist;
298
299 local_irq_save(flags);
300 clist = sd->completion_queue;
301 sd->completion_queue = NULL;
302 local_irq_restore(flags);
303
304 while (clist != NULL) {
305 struct sk_buff *skb = clist;
306 clist = clist->next;
307 if (skb->destructor) {
308 atomic_inc(&skb->users);
309 dev_kfree_skb_any(skb); /* put this one back */
310 } else {
311 __kfree_skb(skb);
312 }
313 }
314 }
315
316 put_cpu_var(softnet_data);
317 }
318
319 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
320 {
321 int count = 0;
322 struct sk_buff *skb;
323
324 zap_completion_queue();
325 refill_skbs();
326 repeat:
327
328 skb = alloc_skb(len, GFP_ATOMIC);
329 if (!skb)
330 skb = skb_dequeue(&skb_pool);
331
332 if (!skb) {
333 if (++count < 10) {
334 netpoll_poll_dev(np->dev);
335 goto repeat;
336 }
337 return NULL;
338 }
339
340 atomic_set(&skb->users, 1);
341 skb_reserve(skb, reserve);
342 return skb;
343 }
344
345 static int netpoll_owner_active(struct net_device *dev)
346 {
347 struct napi_struct *napi;
348
349 list_for_each_entry(napi, &dev->napi_list, dev_list) {
350 if (napi->poll_owner == smp_processor_id())
351 return 1;
352 }
353 return 0;
354 }
355
356 /* call with IRQ disabled */
357 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
358 struct net_device *dev)
359 {
360 int status = NETDEV_TX_BUSY;
361 unsigned long tries;
362 const struct net_device_ops *ops = dev->netdev_ops;
363 /* It is up to the caller to keep npinfo alive. */
364 struct netpoll_info *npinfo;
365
366 WARN_ON_ONCE(!irqs_disabled());
367
368 npinfo = rcu_dereference_bh(np->dev->npinfo);
369 if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
370 __kfree_skb(skb);
371 return;
372 }
373
374 /* don't get messages out of order, and no recursion */
375 if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
376 struct netdev_queue *txq;
377
378 txq = netdev_pick_tx(dev, skb);
379
380 /* try until next clock tick */
381 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
382 tries > 0; --tries) {
383 if (__netif_tx_trylock(txq)) {
384 if (!netif_xmit_stopped(txq)) {
385 if (vlan_tx_tag_present(skb) &&
386 !(netif_skb_features(skb) & NETIF_F_HW_VLAN_CTAG_TX)) {
387 skb = __vlan_put_tag(skb, vlan_tx_tag_get(skb));
388 if (unlikely(!skb))
389 break;
390 skb->vlan_tci = 0;
391 }
392
393 status = ops->ndo_start_xmit(skb, dev);
394 if (status == NETDEV_TX_OK)
395 txq_trans_update(txq);
396 }
397 __netif_tx_unlock(txq);
398
399 if (status == NETDEV_TX_OK)
400 break;
401
402 }
403
404 /* tickle device maybe there is some cleanup */
405 netpoll_poll_dev(np->dev);
406
407 udelay(USEC_PER_POLL);
408 }
409
410 WARN_ONCE(!irqs_disabled(),
411 "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
412 dev->name, ops->ndo_start_xmit);
413
414 }
415
416 if (status != NETDEV_TX_OK) {
417 skb_queue_tail(&npinfo->txq, skb);
418 schedule_delayed_work(&npinfo->tx_work,0);
419 }
420 }
421 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
422
423 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
424 {
425 int total_len, ip_len, udp_len;
426 struct sk_buff *skb;
427 struct udphdr *udph;
428 struct iphdr *iph;
429 struct ethhdr *eth;
430 static atomic_t ip_ident;
431 struct ipv6hdr *ip6h;
432
433 udp_len = len + sizeof(*udph);
434 if (np->ipv6)
435 ip_len = udp_len + sizeof(*ip6h);
436 else
437 ip_len = udp_len + sizeof(*iph);
438
439 total_len = ip_len + LL_RESERVED_SPACE(np->dev);
440
441 skb = find_skb(np, total_len + np->dev->needed_tailroom,
442 total_len - len);
443 if (!skb)
444 return;
445
446 skb_copy_to_linear_data(skb, msg, len);
447 skb_put(skb, len);
448
449 skb_push(skb, sizeof(*udph));
450 skb_reset_transport_header(skb);
451 udph = udp_hdr(skb);
452 udph->source = htons(np->local_port);
453 udph->dest = htons(np->remote_port);
454 udph->len = htons(udp_len);
455
456 if (np->ipv6) {
457 udph->check = 0;
458 udph->check = csum_ipv6_magic(&np->local_ip.in6,
459 &np->remote_ip.in6,
460 udp_len, IPPROTO_UDP,
461 csum_partial(udph, udp_len, 0));
462 if (udph->check == 0)
463 udph->check = CSUM_MANGLED_0;
464
465 skb_push(skb, sizeof(*ip6h));
466 skb_reset_network_header(skb);
467 ip6h = ipv6_hdr(skb);
468
469 /* ip6h->version = 6; ip6h->priority = 0; */
470 put_unaligned(0x60, (unsigned char *)ip6h);
471 ip6h->flow_lbl[0] = 0;
472 ip6h->flow_lbl[1] = 0;
473 ip6h->flow_lbl[2] = 0;
474
475 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
476 ip6h->nexthdr = IPPROTO_UDP;
477 ip6h->hop_limit = 32;
478 ip6h->saddr = np->local_ip.in6;
479 ip6h->daddr = np->remote_ip.in6;
480
481 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
482 skb_reset_mac_header(skb);
483 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
484 } else {
485 udph->check = 0;
486 udph->check = csum_tcpudp_magic(np->local_ip.ip,
487 np->remote_ip.ip,
488 udp_len, IPPROTO_UDP,
489 csum_partial(udph, udp_len, 0));
490 if (udph->check == 0)
491 udph->check = CSUM_MANGLED_0;
492
493 skb_push(skb, sizeof(*iph));
494 skb_reset_network_header(skb);
495 iph = ip_hdr(skb);
496
497 /* iph->version = 4; iph->ihl = 5; */
498 put_unaligned(0x45, (unsigned char *)iph);
499 iph->tos = 0;
500 put_unaligned(htons(ip_len), &(iph->tot_len));
501 iph->id = htons(atomic_inc_return(&ip_ident));
502 iph->frag_off = 0;
503 iph->ttl = 64;
504 iph->protocol = IPPROTO_UDP;
505 iph->check = 0;
506 put_unaligned(np->local_ip.ip, &(iph->saddr));
507 put_unaligned(np->remote_ip.ip, &(iph->daddr));
508 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
509
510 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
511 skb_reset_mac_header(skb);
512 skb->protocol = eth->h_proto = htons(ETH_P_IP);
513 }
514
515 memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
516 memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
517
518 skb->dev = np->dev;
519
520 netpoll_send_skb(np, skb);
521 }
522 EXPORT_SYMBOL(netpoll_send_udp);
523
524 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo)
525 {
526 int size, type = ARPOP_REPLY;
527 __be32 sip, tip;
528 unsigned char *sha;
529 struct sk_buff *send_skb;
530 struct netpoll *np, *tmp;
531 unsigned long flags;
532 int hlen, tlen;
533 int hits = 0, proto;
534
535 if (list_empty(&npinfo->rx_np))
536 return;
537
538 /* Before checking the packet, we do some early
539 inspection whether this is interesting at all */
540 spin_lock_irqsave(&npinfo->rx_lock, flags);
541 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
542 if (np->dev == skb->dev)
543 hits++;
544 }
545 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
546
547 /* No netpoll struct is using this dev */
548 if (!hits)
549 return;
550
551 proto = ntohs(eth_hdr(skb)->h_proto);
552 if (proto == ETH_P_IP) {
553 struct arphdr *arp;
554 unsigned char *arp_ptr;
555 /* No arp on this interface */
556 if (skb->dev->flags & IFF_NOARP)
557 return;
558
559 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
560 return;
561
562 skb_reset_network_header(skb);
563 skb_reset_transport_header(skb);
564 arp = arp_hdr(skb);
565
566 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
567 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
568 arp->ar_pro != htons(ETH_P_IP) ||
569 arp->ar_op != htons(ARPOP_REQUEST))
570 return;
571
572 arp_ptr = (unsigned char *)(arp+1);
573 /* save the location of the src hw addr */
574 sha = arp_ptr;
575 arp_ptr += skb->dev->addr_len;
576 memcpy(&sip, arp_ptr, 4);
577 arp_ptr += 4;
578 /* If we actually cared about dst hw addr,
579 it would get copied here */
580 arp_ptr += skb->dev->addr_len;
581 memcpy(&tip, arp_ptr, 4);
582
583 /* Should we ignore arp? */
584 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
585 return;
586
587 size = arp_hdr_len(skb->dev);
588
589 spin_lock_irqsave(&npinfo->rx_lock, flags);
590 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
591 if (tip != np->local_ip.ip)
592 continue;
593
594 hlen = LL_RESERVED_SPACE(np->dev);
595 tlen = np->dev->needed_tailroom;
596 send_skb = find_skb(np, size + hlen + tlen, hlen);
597 if (!send_skb)
598 continue;
599
600 skb_reset_network_header(send_skb);
601 arp = (struct arphdr *) skb_put(send_skb, size);
602 send_skb->dev = skb->dev;
603 send_skb->protocol = htons(ETH_P_ARP);
604
605 /* Fill the device header for the ARP frame */
606 if (dev_hard_header(send_skb, skb->dev, ETH_P_ARP,
607 sha, np->dev->dev_addr,
608 send_skb->len) < 0) {
609 kfree_skb(send_skb);
610 continue;
611 }
612
613 /*
614 * Fill out the arp protocol part.
615 *
616 * we only support ethernet device type,
617 * which (according to RFC 1390) should
618 * always equal 1 (Ethernet).
619 */
620
621 arp->ar_hrd = htons(np->dev->type);
622 arp->ar_pro = htons(ETH_P_IP);
623 arp->ar_hln = np->dev->addr_len;
624 arp->ar_pln = 4;
625 arp->ar_op = htons(type);
626
627 arp_ptr = (unsigned char *)(arp + 1);
628 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
629 arp_ptr += np->dev->addr_len;
630 memcpy(arp_ptr, &tip, 4);
631 arp_ptr += 4;
632 memcpy(arp_ptr, sha, np->dev->addr_len);
633 arp_ptr += np->dev->addr_len;
634 memcpy(arp_ptr, &sip, 4);
635
636 netpoll_send_skb(np, send_skb);
637
638 /* If there are several rx_hooks for the same address,
639 we're fine by sending a single reply */
640 break;
641 }
642 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
643 } else if( proto == ETH_P_IPV6) {
644 #if IS_ENABLED(CONFIG_IPV6)
645 struct nd_msg *msg;
646 u8 *lladdr = NULL;
647 struct ipv6hdr *hdr;
648 struct icmp6hdr *icmp6h;
649 const struct in6_addr *saddr;
650 const struct in6_addr *daddr;
651 struct inet6_dev *in6_dev = NULL;
652 struct in6_addr *target;
653
654 in6_dev = in6_dev_get(skb->dev);
655 if (!in6_dev || !in6_dev->cnf.accept_ra)
656 return;
657
658 if (!pskb_may_pull(skb, skb->len))
659 return;
660
661 msg = (struct nd_msg *)skb_transport_header(skb);
662
663 __skb_push(skb, skb->data - skb_transport_header(skb));
664
665 if (ipv6_hdr(skb)->hop_limit != 255)
666 return;
667 if (msg->icmph.icmp6_code != 0)
668 return;
669 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
670 return;
671
672 saddr = &ipv6_hdr(skb)->saddr;
673 daddr = &ipv6_hdr(skb)->daddr;
674
675 size = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
676
677 spin_lock_irqsave(&npinfo->rx_lock, flags);
678 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
679 if (!ipv6_addr_equal(daddr, &np->local_ip.in6))
680 continue;
681
682 hlen = LL_RESERVED_SPACE(np->dev);
683 tlen = np->dev->needed_tailroom;
684 send_skb = find_skb(np, size + hlen + tlen, hlen);
685 if (!send_skb)
686 continue;
687
688 send_skb->protocol = htons(ETH_P_IPV6);
689 send_skb->dev = skb->dev;
690
691 skb_reset_network_header(send_skb);
692 skb_put(send_skb, sizeof(struct ipv6hdr));
693 hdr = ipv6_hdr(send_skb);
694
695 *(__be32*)hdr = htonl(0x60000000);
696
697 hdr->payload_len = htons(size);
698 hdr->nexthdr = IPPROTO_ICMPV6;
699 hdr->hop_limit = 255;
700 hdr->saddr = *saddr;
701 hdr->daddr = *daddr;
702
703 send_skb->transport_header = send_skb->tail;
704 skb_put(send_skb, size);
705
706 icmp6h = (struct icmp6hdr *)skb_transport_header(skb);
707 icmp6h->icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
708 icmp6h->icmp6_router = 0;
709 icmp6h->icmp6_solicited = 1;
710 target = (struct in6_addr *)(skb_transport_header(send_skb) + sizeof(struct icmp6hdr));
711 *target = msg->target;
712 icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, size,
713 IPPROTO_ICMPV6,
714 csum_partial(icmp6h,
715 size, 0));
716
717 if (dev_hard_header(send_skb, skb->dev, ETH_P_IPV6,
718 lladdr, np->dev->dev_addr,
719 send_skb->len) < 0) {
720 kfree_skb(send_skb);
721 continue;
722 }
723
724 netpoll_send_skb(np, send_skb);
725
726 /* If there are several rx_hooks for the same address,
727 we're fine by sending a single reply */
728 break;
729 }
730 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
731 #endif
732 }
733 }
734
735 static bool pkt_is_ns(struct sk_buff *skb)
736 {
737 struct nd_msg *msg;
738 struct ipv6hdr *hdr;
739
740 if (skb->protocol != htons(ETH_P_ARP))
741 return false;
742 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct nd_msg)))
743 return false;
744
745 msg = (struct nd_msg *)skb_transport_header(skb);
746 __skb_push(skb, skb->data - skb_transport_header(skb));
747 hdr = ipv6_hdr(skb);
748
749 if (hdr->nexthdr != IPPROTO_ICMPV6)
750 return false;
751 if (hdr->hop_limit != 255)
752 return false;
753 if (msg->icmph.icmp6_code != 0)
754 return false;
755 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
756 return false;
757
758 return true;
759 }
760
761 int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo)
762 {
763 int proto, len, ulen;
764 int hits = 0;
765 const struct iphdr *iph;
766 struct udphdr *uh;
767 struct netpoll *np, *tmp;
768
769 if (list_empty(&npinfo->rx_np))
770 goto out;
771
772 if (skb->dev->type != ARPHRD_ETHER)
773 goto out;
774
775 /* check if netpoll clients need ARP */
776 if (skb->protocol == htons(ETH_P_ARP) && atomic_read(&trapped)) {
777 skb_queue_tail(&npinfo->neigh_tx, skb);
778 return 1;
779 } else if (pkt_is_ns(skb) && atomic_read(&trapped)) {
780 skb_queue_tail(&npinfo->neigh_tx, skb);
781 return 1;
782 }
783
784 if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
785 skb = vlan_untag(skb);
786 if (unlikely(!skb))
787 goto out;
788 }
789
790 proto = ntohs(eth_hdr(skb)->h_proto);
791 if (proto != ETH_P_IP && proto != ETH_P_IPV6)
792 goto out;
793 if (skb->pkt_type == PACKET_OTHERHOST)
794 goto out;
795 if (skb_shared(skb))
796 goto out;
797
798 if (proto == ETH_P_IP) {
799 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
800 goto out;
801 iph = (struct iphdr *)skb->data;
802 if (iph->ihl < 5 || iph->version != 4)
803 goto out;
804 if (!pskb_may_pull(skb, iph->ihl*4))
805 goto out;
806 iph = (struct iphdr *)skb->data;
807 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
808 goto out;
809
810 len = ntohs(iph->tot_len);
811 if (skb->len < len || len < iph->ihl*4)
812 goto out;
813
814 /*
815 * Our transport medium may have padded the buffer out.
816 * Now We trim to the true length of the frame.
817 */
818 if (pskb_trim_rcsum(skb, len))
819 goto out;
820
821 iph = (struct iphdr *)skb->data;
822 if (iph->protocol != IPPROTO_UDP)
823 goto out;
824
825 len -= iph->ihl*4;
826 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
827 ulen = ntohs(uh->len);
828
829 if (ulen != len)
830 goto out;
831 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
832 goto out;
833 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
834 if (np->local_ip.ip && np->local_ip.ip != iph->daddr)
835 continue;
836 if (np->remote_ip.ip && np->remote_ip.ip != iph->saddr)
837 continue;
838 if (np->local_port && np->local_port != ntohs(uh->dest))
839 continue;
840
841 np->rx_hook(np, ntohs(uh->source),
842 (char *)(uh+1),
843 ulen - sizeof(struct udphdr));
844 hits++;
845 }
846 } else {
847 #if IS_ENABLED(CONFIG_IPV6)
848 const struct ipv6hdr *ip6h;
849
850 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
851 goto out;
852 ip6h = (struct ipv6hdr *)skb->data;
853 if (ip6h->version != 6)
854 goto out;
855 len = ntohs(ip6h->payload_len);
856 if (!len)
857 goto out;
858 if (len + sizeof(struct ipv6hdr) > skb->len)
859 goto out;
860 if (pskb_trim_rcsum(skb, len + sizeof(struct ipv6hdr)))
861 goto out;
862 ip6h = ipv6_hdr(skb);
863 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
864 goto out;
865 uh = udp_hdr(skb);
866 ulen = ntohs(uh->len);
867 if (ulen != skb->len)
868 goto out;
869 if (udp6_csum_init(skb, uh, IPPROTO_UDP))
870 goto out;
871 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
872 if (!ipv6_addr_equal(&np->local_ip.in6, &ip6h->daddr))
873 continue;
874 if (!ipv6_addr_equal(&np->remote_ip.in6, &ip6h->saddr))
875 continue;
876 if (np->local_port && np->local_port != ntohs(uh->dest))
877 continue;
878
879 np->rx_hook(np, ntohs(uh->source),
880 (char *)(uh+1),
881 ulen - sizeof(struct udphdr));
882 hits++;
883 }
884 #endif
885 }
886
887 if (!hits)
888 goto out;
889
890 kfree_skb(skb);
891 return 1;
892
893 out:
894 if (atomic_read(&trapped)) {
895 kfree_skb(skb);
896 return 1;
897 }
898
899 return 0;
900 }
901
902 void netpoll_print_options(struct netpoll *np)
903 {
904 np_info(np, "local port %d\n", np->local_port);
905 if (np->ipv6)
906 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
907 else
908 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
909 np_info(np, "interface '%s'\n", np->dev_name);
910 np_info(np, "remote port %d\n", np->remote_port);
911 if (np->ipv6)
912 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
913 else
914 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
915 np_info(np, "remote ethernet address %pM\n", np->remote_mac);
916 }
917 EXPORT_SYMBOL(netpoll_print_options);
918
919 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
920 {
921 const char *end;
922
923 if (!strchr(str, ':') &&
924 in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
925 if (!*end)
926 return 0;
927 }
928 if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
929 #if IS_ENABLED(CONFIG_IPV6)
930 if (!*end)
931 return 1;
932 #else
933 return -1;
934 #endif
935 }
936 return -1;
937 }
938
939 int netpoll_parse_options(struct netpoll *np, char *opt)
940 {
941 char *cur=opt, *delim;
942 int ipv6;
943
944 if (*cur != '@') {
945 if ((delim = strchr(cur, '@')) == NULL)
946 goto parse_failed;
947 *delim = 0;
948 if (kstrtou16(cur, 10, &np->local_port))
949 goto parse_failed;
950 cur = delim;
951 }
952 cur++;
953
954 if (*cur != '/') {
955 if ((delim = strchr(cur, '/')) == NULL)
956 goto parse_failed;
957 *delim = 0;
958 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
959 if (ipv6 < 0)
960 goto parse_failed;
961 else
962 np->ipv6 = (bool)ipv6;
963 cur = delim;
964 }
965 cur++;
966
967 if (*cur != ',') {
968 /* parse out dev name */
969 if ((delim = strchr(cur, ',')) == NULL)
970 goto parse_failed;
971 *delim = 0;
972 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
973 cur = delim;
974 }
975 cur++;
976
977 if (*cur != '@') {
978 /* dst port */
979 if ((delim = strchr(cur, '@')) == NULL)
980 goto parse_failed;
981 *delim = 0;
982 if (*cur == ' ' || *cur == '\t')
983 np_info(np, "warning: whitespace is not allowed\n");
984 if (kstrtou16(cur, 10, &np->remote_port))
985 goto parse_failed;
986 cur = delim;
987 }
988 cur++;
989
990 /* dst ip */
991 if ((delim = strchr(cur, '/')) == NULL)
992 goto parse_failed;
993 *delim = 0;
994 ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
995 if (ipv6 < 0)
996 goto parse_failed;
997 else if (np->ipv6 != (bool)ipv6)
998 goto parse_failed;
999 else
1000 np->ipv6 = (bool)ipv6;
1001 cur = delim + 1;
1002
1003 if (*cur != 0) {
1004 /* MAC address */
1005 if (!mac_pton(cur, np->remote_mac))
1006 goto parse_failed;
1007 }
1008
1009 netpoll_print_options(np);
1010
1011 return 0;
1012
1013 parse_failed:
1014 np_info(np, "couldn't parse config at '%s'!\n", cur);
1015 return -1;
1016 }
1017 EXPORT_SYMBOL(netpoll_parse_options);
1018
1019 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
1020 {
1021 struct netpoll_info *npinfo;
1022 const struct net_device_ops *ops;
1023 unsigned long flags;
1024 int err;
1025
1026 np->dev = ndev;
1027 strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
1028 INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
1029
1030 if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
1031 !ndev->netdev_ops->ndo_poll_controller) {
1032 np_err(np, "%s doesn't support polling, aborting\n",
1033 np->dev_name);
1034 err = -ENOTSUPP;
1035 goto out;
1036 }
1037
1038 if (!ndev->npinfo) {
1039 npinfo = kmalloc(sizeof(*npinfo), gfp);
1040 if (!npinfo) {
1041 err = -ENOMEM;
1042 goto out;
1043 }
1044
1045 npinfo->rx_flags = 0;
1046 INIT_LIST_HEAD(&npinfo->rx_np);
1047
1048 spin_lock_init(&npinfo->rx_lock);
1049 mutex_init(&npinfo->dev_lock);
1050 skb_queue_head_init(&npinfo->neigh_tx);
1051 skb_queue_head_init(&npinfo->txq);
1052 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
1053
1054 atomic_set(&npinfo->refcnt, 1);
1055
1056 ops = np->dev->netdev_ops;
1057 if (ops->ndo_netpoll_setup) {
1058 err = ops->ndo_netpoll_setup(ndev, npinfo, gfp);
1059 if (err)
1060 goto free_npinfo;
1061 }
1062 } else {
1063 npinfo = rtnl_dereference(ndev->npinfo);
1064 atomic_inc(&npinfo->refcnt);
1065 }
1066
1067 npinfo->netpoll = np;
1068
1069 if (np->rx_hook) {
1070 spin_lock_irqsave(&npinfo->rx_lock, flags);
1071 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
1072 list_add_tail(&np->rx, &npinfo->rx_np);
1073 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1074 }
1075
1076 /* last thing to do is link it to the net device structure */
1077 rcu_assign_pointer(ndev->npinfo, npinfo);
1078
1079 return 0;
1080
1081 free_npinfo:
1082 kfree(npinfo);
1083 out:
1084 return err;
1085 }
1086 EXPORT_SYMBOL_GPL(__netpoll_setup);
1087
1088 int netpoll_setup(struct netpoll *np)
1089 {
1090 struct net_device *ndev = NULL;
1091 struct in_device *in_dev;
1092 int err;
1093
1094 rtnl_lock();
1095 if (np->dev_name) {
1096 struct net *net = current->nsproxy->net_ns;
1097 ndev = __dev_get_by_name(net, np->dev_name);
1098 }
1099 if (!ndev) {
1100 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
1101 err = -ENODEV;
1102 goto unlock;
1103 }
1104 dev_hold(ndev);
1105
1106 if (netdev_master_upper_dev_get(ndev)) {
1107 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
1108 err = -EBUSY;
1109 goto put;
1110 }
1111
1112 if (!netif_running(ndev)) {
1113 unsigned long atmost, atleast;
1114
1115 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
1116
1117 err = dev_open(ndev);
1118
1119 if (err) {
1120 np_err(np, "failed to open %s\n", ndev->name);
1121 goto put;
1122 }
1123
1124 rtnl_unlock();
1125 atleast = jiffies + HZ/10;
1126 atmost = jiffies + carrier_timeout * HZ;
1127 while (!netif_carrier_ok(ndev)) {
1128 if (time_after(jiffies, atmost)) {
1129 np_notice(np, "timeout waiting for carrier\n");
1130 break;
1131 }
1132 msleep(1);
1133 }
1134
1135 /* If carrier appears to come up instantly, we don't
1136 * trust it and pause so that we don't pump all our
1137 * queued console messages into the bitbucket.
1138 */
1139
1140 if (time_before(jiffies, atleast)) {
1141 np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
1142 msleep(4000);
1143 }
1144 rtnl_lock();
1145 }
1146
1147 if (!np->local_ip.ip) {
1148 if (!np->ipv6) {
1149 in_dev = __in_dev_get_rtnl(ndev);
1150
1151 if (!in_dev || !in_dev->ifa_list) {
1152 np_err(np, "no IP address for %s, aborting\n",
1153 np->dev_name);
1154 err = -EDESTADDRREQ;
1155 goto put;
1156 }
1157
1158 np->local_ip.ip = in_dev->ifa_list->ifa_local;
1159 np_info(np, "local IP %pI4\n", &np->local_ip.ip);
1160 } else {
1161 #if IS_ENABLED(CONFIG_IPV6)
1162 struct inet6_dev *idev;
1163
1164 err = -EDESTADDRREQ;
1165 idev = __in6_dev_get(ndev);
1166 if (idev) {
1167 struct inet6_ifaddr *ifp;
1168
1169 read_lock_bh(&idev->lock);
1170 list_for_each_entry(ifp, &idev->addr_list, if_list) {
1171 if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
1172 continue;
1173 np->local_ip.in6 = ifp->addr;
1174 err = 0;
1175 break;
1176 }
1177 read_unlock_bh(&idev->lock);
1178 }
1179 if (err) {
1180 np_err(np, "no IPv6 address for %s, aborting\n",
1181 np->dev_name);
1182 goto put;
1183 } else
1184 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
1185 #else
1186 np_err(np, "IPv6 is not supported %s, aborting\n",
1187 np->dev_name);
1188 err = -EINVAL;
1189 goto put;
1190 #endif
1191 }
1192 }
1193
1194 /* fill up the skb queue */
1195 refill_skbs();
1196
1197 err = __netpoll_setup(np, ndev, GFP_KERNEL);
1198 if (err)
1199 goto put;
1200
1201 rtnl_unlock();
1202 return 0;
1203
1204 put:
1205 dev_put(ndev);
1206 unlock:
1207 rtnl_unlock();
1208 return err;
1209 }
1210 EXPORT_SYMBOL(netpoll_setup);
1211
1212 static int __init netpoll_init(void)
1213 {
1214 skb_queue_head_init(&skb_pool);
1215 return 0;
1216 }
1217 core_initcall(netpoll_init);
1218
1219 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
1220 {
1221 struct netpoll_info *npinfo =
1222 container_of(rcu_head, struct netpoll_info, rcu);
1223
1224 skb_queue_purge(&npinfo->neigh_tx);
1225 skb_queue_purge(&npinfo->txq);
1226
1227 /* we can't call cancel_delayed_work_sync here, as we are in softirq */
1228 cancel_delayed_work(&npinfo->tx_work);
1229
1230 /* clean after last, unfinished work */
1231 __skb_queue_purge(&npinfo->txq);
1232 /* now cancel it again */
1233 cancel_delayed_work(&npinfo->tx_work);
1234 kfree(npinfo);
1235 }
1236
1237 void __netpoll_cleanup(struct netpoll *np)
1238 {
1239 struct netpoll_info *npinfo;
1240 unsigned long flags;
1241
1242 /* rtnl_dereference would be preferable here but
1243 * rcu_cleanup_netpoll path can put us in here safely without
1244 * holding the rtnl, so plain rcu_dereference it is
1245 */
1246 npinfo = rtnl_dereference(np->dev->npinfo);
1247 if (!npinfo)
1248 return;
1249
1250 if (!list_empty(&npinfo->rx_np)) {
1251 spin_lock_irqsave(&npinfo->rx_lock, flags);
1252 list_del(&np->rx);
1253 if (list_empty(&npinfo->rx_np))
1254 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
1255 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1256 }
1257
1258 synchronize_srcu(&netpoll_srcu);
1259
1260 if (atomic_dec_and_test(&npinfo->refcnt)) {
1261 const struct net_device_ops *ops;
1262
1263 ops = np->dev->netdev_ops;
1264 if (ops->ndo_netpoll_cleanup)
1265 ops->ndo_netpoll_cleanup(np->dev);
1266
1267 rcu_assign_pointer(np->dev->npinfo, NULL);
1268 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
1269 }
1270 }
1271 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
1272
1273 static void netpoll_async_cleanup(struct work_struct *work)
1274 {
1275 struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
1276
1277 rtnl_lock();
1278 __netpoll_cleanup(np);
1279 rtnl_unlock();
1280 kfree(np);
1281 }
1282
1283 void __netpoll_free_async(struct netpoll *np)
1284 {
1285 schedule_work(&np->cleanup_work);
1286 }
1287 EXPORT_SYMBOL_GPL(__netpoll_free_async);
1288
1289 void netpoll_cleanup(struct netpoll *np)
1290 {
1291 if (!np->dev)
1292 return;
1293
1294 rtnl_lock();
1295 __netpoll_cleanup(np);
1296 rtnl_unlock();
1297
1298 dev_put(np->dev);
1299 np->dev = NULL;
1300 }
1301 EXPORT_SYMBOL(netpoll_cleanup);
1302
1303 int netpoll_trap(void)
1304 {
1305 return atomic_read(&trapped);
1306 }
1307 EXPORT_SYMBOL(netpoll_trap);
1308
1309 void netpoll_set_trap(int trap)
1310 {
1311 if (trap)
1312 atomic_inc(&trapped);
1313 else
1314 atomic_dec(&trapped);
1315 }
1316 EXPORT_SYMBOL(netpoll_set_trap);
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