GNU Linux-libre 5.10.219-gnu1
[releases.git] / net / core / netpoll.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Common framework for low-level network console, dump, and debugger code
4  *
5  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
6  *
7  * based on the netconsole code from:
8  *
9  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
10  * Copyright (C) 2002  Red Hat, Inc.
11  */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/moduleparam.h>
16 #include <linux/kernel.h>
17 #include <linux/netdevice.h>
18 #include <linux/etherdevice.h>
19 #include <linux/string.h>
20 #include <linux/if_arp.h>
21 #include <linux/inetdevice.h>
22 #include <linux/inet.h>
23 #include <linux/interrupt.h>
24 #include <linux/netpoll.h>
25 #include <linux/sched.h>
26 #include <linux/delay.h>
27 #include <linux/rcupdate.h>
28 #include <linux/workqueue.h>
29 #include <linux/slab.h>
30 #include <linux/export.h>
31 #include <linux/if_vlan.h>
32 #include <net/dsa.h>
33 #include <net/tcp.h>
34 #include <net/udp.h>
35 #include <net/addrconf.h>
36 #include <net/ndisc.h>
37 #include <net/ip6_checksum.h>
38 #include <asm/unaligned.h>
39 #include <trace/events/napi.h>
40
41 /*
42  * We maintain a small pool of fully-sized skbs, to make sure the
43  * message gets out even in extreme OOM situations.
44  */
45
46 #define MAX_UDP_CHUNK 1460
47 #define MAX_SKBS 32
48
49 static struct sk_buff_head skb_pool;
50
51 DEFINE_STATIC_SRCU(netpoll_srcu);
52
53 #define USEC_PER_POLL   50
54
55 #define MAX_SKB_SIZE                                                    \
56         (sizeof(struct ethhdr) +                                        \
57          sizeof(struct iphdr) +                                         \
58          sizeof(struct udphdr) +                                        \
59          MAX_UDP_CHUNK)
60
61 static void zap_completion_queue(void);
62
63 static unsigned int carrier_timeout = 4;
64 module_param(carrier_timeout, uint, 0644);
65
66 #define np_info(np, fmt, ...)                           \
67         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
68 #define np_err(np, fmt, ...)                            \
69         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
70 #define np_notice(np, fmt, ...)                         \
71         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
72
73 static netdev_tx_t netpoll_start_xmit(struct sk_buff *skb,
74                                       struct net_device *dev,
75                                       struct netdev_queue *txq)
76 {
77         netdev_tx_t status = NETDEV_TX_OK;
78         netdev_features_t features;
79
80         features = netif_skb_features(skb);
81
82         if (skb_vlan_tag_present(skb) &&
83             !vlan_hw_offload_capable(features, skb->vlan_proto)) {
84                 skb = __vlan_hwaccel_push_inside(skb);
85                 if (unlikely(!skb)) {
86                         /* This is actually a packet drop, but we
87                          * don't want the code that calls this
88                          * function to try and operate on a NULL skb.
89                          */
90                         goto out;
91                 }
92         }
93
94         status = netdev_start_xmit(skb, dev, txq, false);
95
96 out:
97         return status;
98 }
99
100 static void queue_process(struct work_struct *work)
101 {
102         struct netpoll_info *npinfo =
103                 container_of(work, struct netpoll_info, tx_work.work);
104         struct sk_buff *skb;
105         unsigned long flags;
106
107         while ((skb = skb_dequeue(&npinfo->txq))) {
108                 struct net_device *dev = skb->dev;
109                 struct netdev_queue *txq;
110                 unsigned int q_index;
111
112                 if (!netif_device_present(dev) || !netif_running(dev)) {
113                         kfree_skb(skb);
114                         continue;
115                 }
116
117                 local_irq_save(flags);
118                 /* check if skb->queue_mapping is still valid */
119                 q_index = skb_get_queue_mapping(skb);
120                 if (unlikely(q_index >= dev->real_num_tx_queues)) {
121                         q_index = q_index % dev->real_num_tx_queues;
122                         skb_set_queue_mapping(skb, q_index);
123                 }
124                 txq = netdev_get_tx_queue(dev, q_index);
125                 HARD_TX_LOCK(dev, txq, smp_processor_id());
126                 if (netif_xmit_frozen_or_stopped(txq) ||
127                     !dev_xmit_complete(netpoll_start_xmit(skb, dev, txq))) {
128                         skb_queue_head(&npinfo->txq, skb);
129                         HARD_TX_UNLOCK(dev, txq);
130                         local_irq_restore(flags);
131
132                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
133                         return;
134                 }
135                 HARD_TX_UNLOCK(dev, txq);
136                 local_irq_restore(flags);
137         }
138 }
139
140 static int netif_local_xmit_active(struct net_device *dev)
141 {
142         int i;
143
144         for (i = 0; i < dev->num_tx_queues; i++) {
145                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
146
147                 if (READ_ONCE(txq->xmit_lock_owner) == smp_processor_id())
148                         return 1;
149         }
150
151         return 0;
152 }
153
154 static void poll_one_napi(struct napi_struct *napi)
155 {
156         int work;
157
158         /* If we set this bit but see that it has already been set,
159          * that indicates that napi has been disabled and we need
160          * to abort this operation
161          */
162         if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
163                 return;
164
165         /* We explicilty pass the polling call a budget of 0 to
166          * indicate that we are clearing the Tx path only.
167          */
168         work = napi->poll(napi, 0);
169         WARN_ONCE(work, "%pS exceeded budget in poll\n", napi->poll);
170         trace_napi_poll(napi, work, 0);
171
172         clear_bit(NAPI_STATE_NPSVC, &napi->state);
173 }
174
175 static void poll_napi(struct net_device *dev)
176 {
177         struct napi_struct *napi;
178         int cpu = smp_processor_id();
179
180         list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
181                 if (cmpxchg(&napi->poll_owner, -1, cpu) == -1) {
182                         poll_one_napi(napi);
183                         smp_store_release(&napi->poll_owner, -1);
184                 }
185         }
186 }
187
188 void netpoll_poll_dev(struct net_device *dev)
189 {
190         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
191         const struct net_device_ops *ops;
192
193         /* Don't do any rx activity if the dev_lock mutex is held
194          * the dev_open/close paths use this to block netpoll activity
195          * while changing device state
196          */
197         if (!ni || down_trylock(&ni->dev_lock))
198                 return;
199
200         /* Some drivers will take the same locks in poll and xmit,
201          * we can't poll if local CPU is already in xmit.
202          */
203         if (!netif_running(dev) || netif_local_xmit_active(dev)) {
204                 up(&ni->dev_lock);
205                 return;
206         }
207
208         ops = dev->netdev_ops;
209         if (ops->ndo_poll_controller)
210                 ops->ndo_poll_controller(dev);
211
212         poll_napi(dev);
213
214         up(&ni->dev_lock);
215
216         zap_completion_queue();
217 }
218 EXPORT_SYMBOL(netpoll_poll_dev);
219
220 void netpoll_poll_disable(struct net_device *dev)
221 {
222         struct netpoll_info *ni;
223         int idx;
224         might_sleep();
225         idx = srcu_read_lock(&netpoll_srcu);
226         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
227         if (ni)
228                 down(&ni->dev_lock);
229         srcu_read_unlock(&netpoll_srcu, idx);
230 }
231 EXPORT_SYMBOL(netpoll_poll_disable);
232
233 void netpoll_poll_enable(struct net_device *dev)
234 {
235         struct netpoll_info *ni;
236         rcu_read_lock();
237         ni = rcu_dereference(dev->npinfo);
238         if (ni)
239                 up(&ni->dev_lock);
240         rcu_read_unlock();
241 }
242 EXPORT_SYMBOL(netpoll_poll_enable);
243
244 static void refill_skbs(void)
245 {
246         struct sk_buff *skb;
247         unsigned long flags;
248
249         spin_lock_irqsave(&skb_pool.lock, flags);
250         while (skb_pool.qlen < MAX_SKBS) {
251                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
252                 if (!skb)
253                         break;
254
255                 __skb_queue_tail(&skb_pool, skb);
256         }
257         spin_unlock_irqrestore(&skb_pool.lock, flags);
258 }
259
260 static void zap_completion_queue(void)
261 {
262         unsigned long flags;
263         struct softnet_data *sd = &get_cpu_var(softnet_data);
264
265         if (sd->completion_queue) {
266                 struct sk_buff *clist;
267
268                 local_irq_save(flags);
269                 clist = sd->completion_queue;
270                 sd->completion_queue = NULL;
271                 local_irq_restore(flags);
272
273                 while (clist != NULL) {
274                         struct sk_buff *skb = clist;
275                         clist = clist->next;
276                         if (!skb_irq_freeable(skb)) {
277                                 refcount_set(&skb->users, 1);
278                                 dev_kfree_skb_any(skb); /* put this one back */
279                         } else {
280                                 __kfree_skb(skb);
281                         }
282                 }
283         }
284
285         put_cpu_var(softnet_data);
286 }
287
288 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
289 {
290         int count = 0;
291         struct sk_buff *skb;
292
293         zap_completion_queue();
294         refill_skbs();
295 repeat:
296
297         skb = alloc_skb(len, GFP_ATOMIC);
298         if (!skb)
299                 skb = skb_dequeue(&skb_pool);
300
301         if (!skb) {
302                 if (++count < 10) {
303                         netpoll_poll_dev(np->dev);
304                         goto repeat;
305                 }
306                 return NULL;
307         }
308
309         refcount_set(&skb->users, 1);
310         skb_reserve(skb, reserve);
311         return skb;
312 }
313
314 static int netpoll_owner_active(struct net_device *dev)
315 {
316         struct napi_struct *napi;
317
318         list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
319                 if (napi->poll_owner == smp_processor_id())
320                         return 1;
321         }
322         return 0;
323 }
324
325 /* call with IRQ disabled */
326 static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
327 {
328         netdev_tx_t status = NETDEV_TX_BUSY;
329         struct net_device *dev;
330         unsigned long tries;
331         /* It is up to the caller to keep npinfo alive. */
332         struct netpoll_info *npinfo;
333
334         lockdep_assert_irqs_disabled();
335
336         dev = np->dev;
337         npinfo = rcu_dereference_bh(dev->npinfo);
338
339         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
340                 dev_kfree_skb_irq(skb);
341                 return NET_XMIT_DROP;
342         }
343
344         /* don't get messages out of order, and no recursion */
345         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
346                 struct netdev_queue *txq;
347
348                 txq = netdev_core_pick_tx(dev, skb, NULL);
349
350                 /* try until next clock tick */
351                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
352                      tries > 0; --tries) {
353                         if (HARD_TX_TRYLOCK(dev, txq)) {
354                                 if (!netif_xmit_stopped(txq))
355                                         status = netpoll_start_xmit(skb, dev, txq);
356
357                                 HARD_TX_UNLOCK(dev, txq);
358
359                                 if (dev_xmit_complete(status))
360                                         break;
361
362                         }
363
364                         /* tickle device maybe there is some cleanup */
365                         netpoll_poll_dev(np->dev);
366
367                         udelay(USEC_PER_POLL);
368                 }
369
370                 WARN_ONCE(!irqs_disabled(),
371                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pS)\n",
372                         dev->name, dev->netdev_ops->ndo_start_xmit);
373
374         }
375
376         if (!dev_xmit_complete(status)) {
377                 skb_queue_tail(&npinfo->txq, skb);
378                 schedule_delayed_work(&npinfo->tx_work,0);
379         }
380         return NETDEV_TX_OK;
381 }
382
383 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
384 {
385         unsigned long flags;
386         netdev_tx_t ret;
387
388         if (unlikely(!np)) {
389                 dev_kfree_skb_irq(skb);
390                 ret = NET_XMIT_DROP;
391         } else {
392                 local_irq_save(flags);
393                 ret = __netpoll_send_skb(np, skb);
394                 local_irq_restore(flags);
395         }
396         return ret;
397 }
398 EXPORT_SYMBOL(netpoll_send_skb);
399
400 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
401 {
402         int total_len, ip_len, udp_len;
403         struct sk_buff *skb;
404         struct udphdr *udph;
405         struct iphdr *iph;
406         struct ethhdr *eth;
407         static atomic_t ip_ident;
408         struct ipv6hdr *ip6h;
409
410         WARN_ON_ONCE(!irqs_disabled());
411
412         udp_len = len + sizeof(*udph);
413         if (np->ipv6)
414                 ip_len = udp_len + sizeof(*ip6h);
415         else
416                 ip_len = udp_len + sizeof(*iph);
417
418         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
419
420         skb = find_skb(np, total_len + np->dev->needed_tailroom,
421                        total_len - len);
422         if (!skb)
423                 return;
424
425         skb_copy_to_linear_data(skb, msg, len);
426         skb_put(skb, len);
427
428         skb_push(skb, sizeof(*udph));
429         skb_reset_transport_header(skb);
430         udph = udp_hdr(skb);
431         udph->source = htons(np->local_port);
432         udph->dest = htons(np->remote_port);
433         udph->len = htons(udp_len);
434
435         if (np->ipv6) {
436                 udph->check = 0;
437                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
438                                               &np->remote_ip.in6,
439                                               udp_len, IPPROTO_UDP,
440                                               csum_partial(udph, udp_len, 0));
441                 if (udph->check == 0)
442                         udph->check = CSUM_MANGLED_0;
443
444                 skb_push(skb, sizeof(*ip6h));
445                 skb_reset_network_header(skb);
446                 ip6h = ipv6_hdr(skb);
447
448                 /* ip6h->version = 6; ip6h->priority = 0; */
449                 put_unaligned(0x60, (unsigned char *)ip6h);
450                 ip6h->flow_lbl[0] = 0;
451                 ip6h->flow_lbl[1] = 0;
452                 ip6h->flow_lbl[2] = 0;
453
454                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
455                 ip6h->nexthdr = IPPROTO_UDP;
456                 ip6h->hop_limit = 32;
457                 ip6h->saddr = np->local_ip.in6;
458                 ip6h->daddr = np->remote_ip.in6;
459
460                 eth = skb_push(skb, ETH_HLEN);
461                 skb_reset_mac_header(skb);
462                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
463         } else {
464                 udph->check = 0;
465                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
466                                                 np->remote_ip.ip,
467                                                 udp_len, IPPROTO_UDP,
468                                                 csum_partial(udph, udp_len, 0));
469                 if (udph->check == 0)
470                         udph->check = CSUM_MANGLED_0;
471
472                 skb_push(skb, sizeof(*iph));
473                 skb_reset_network_header(skb);
474                 iph = ip_hdr(skb);
475
476                 /* iph->version = 4; iph->ihl = 5; */
477                 put_unaligned(0x45, (unsigned char *)iph);
478                 iph->tos      = 0;
479                 put_unaligned(htons(ip_len), &(iph->tot_len));
480                 iph->id       = htons(atomic_inc_return(&ip_ident));
481                 iph->frag_off = 0;
482                 iph->ttl      = 64;
483                 iph->protocol = IPPROTO_UDP;
484                 iph->check    = 0;
485                 put_unaligned(np->local_ip.ip, &(iph->saddr));
486                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
487                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
488
489                 eth = skb_push(skb, ETH_HLEN);
490                 skb_reset_mac_header(skb);
491                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
492         }
493
494         ether_addr_copy(eth->h_source, np->dev->dev_addr);
495         ether_addr_copy(eth->h_dest, np->remote_mac);
496
497         skb->dev = np->dev;
498
499         netpoll_send_skb(np, skb);
500 }
501 EXPORT_SYMBOL(netpoll_send_udp);
502
503 void netpoll_print_options(struct netpoll *np)
504 {
505         np_info(np, "local port %d\n", np->local_port);
506         if (np->ipv6)
507                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
508         else
509                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
510         np_info(np, "interface '%s'\n", np->dev_name);
511         np_info(np, "remote port %d\n", np->remote_port);
512         if (np->ipv6)
513                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
514         else
515                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
516         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
517 }
518 EXPORT_SYMBOL(netpoll_print_options);
519
520 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
521 {
522         const char *end;
523
524         if (!strchr(str, ':') &&
525             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
526                 if (!*end)
527                         return 0;
528         }
529         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
530 #if IS_ENABLED(CONFIG_IPV6)
531                 if (!*end)
532                         return 1;
533 #else
534                 return -1;
535 #endif
536         }
537         return -1;
538 }
539
540 int netpoll_parse_options(struct netpoll *np, char *opt)
541 {
542         char *cur=opt, *delim;
543         int ipv6;
544         bool ipversion_set = false;
545
546         if (*cur != '@') {
547                 if ((delim = strchr(cur, '@')) == NULL)
548                         goto parse_failed;
549                 *delim = 0;
550                 if (kstrtou16(cur, 10, &np->local_port))
551                         goto parse_failed;
552                 cur = delim;
553         }
554         cur++;
555
556         if (*cur != '/') {
557                 ipversion_set = true;
558                 if ((delim = strchr(cur, '/')) == NULL)
559                         goto parse_failed;
560                 *delim = 0;
561                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
562                 if (ipv6 < 0)
563                         goto parse_failed;
564                 else
565                         np->ipv6 = (bool)ipv6;
566                 cur = delim;
567         }
568         cur++;
569
570         if (*cur != ',') {
571                 /* parse out dev name */
572                 if ((delim = strchr(cur, ',')) == NULL)
573                         goto parse_failed;
574                 *delim = 0;
575                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
576                 cur = delim;
577         }
578         cur++;
579
580         if (*cur != '@') {
581                 /* dst port */
582                 if ((delim = strchr(cur, '@')) == NULL)
583                         goto parse_failed;
584                 *delim = 0;
585                 if (*cur == ' ' || *cur == '\t')
586                         np_info(np, "warning: whitespace is not allowed\n");
587                 if (kstrtou16(cur, 10, &np->remote_port))
588                         goto parse_failed;
589                 cur = delim;
590         }
591         cur++;
592
593         /* dst ip */
594         if ((delim = strchr(cur, '/')) == NULL)
595                 goto parse_failed;
596         *delim = 0;
597         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
598         if (ipv6 < 0)
599                 goto parse_failed;
600         else if (ipversion_set && np->ipv6 != (bool)ipv6)
601                 goto parse_failed;
602         else
603                 np->ipv6 = (bool)ipv6;
604         cur = delim + 1;
605
606         if (*cur != 0) {
607                 /* MAC address */
608                 if (!mac_pton(cur, np->remote_mac))
609                         goto parse_failed;
610         }
611
612         netpoll_print_options(np);
613
614         return 0;
615
616  parse_failed:
617         np_info(np, "couldn't parse config at '%s'!\n", cur);
618         return -1;
619 }
620 EXPORT_SYMBOL(netpoll_parse_options);
621
622 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
623 {
624         struct netpoll_info *npinfo;
625         const struct net_device_ops *ops;
626         int err;
627
628         np->dev = ndev;
629         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
630
631         if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {
632                 np_err(np, "%s doesn't support polling, aborting\n",
633                        np->dev_name);
634                 err = -ENOTSUPP;
635                 goto out;
636         }
637
638         if (!ndev->npinfo) {
639                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
640                 if (!npinfo) {
641                         err = -ENOMEM;
642                         goto out;
643                 }
644
645                 sema_init(&npinfo->dev_lock, 1);
646                 skb_queue_head_init(&npinfo->txq);
647                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
648
649                 refcount_set(&npinfo->refcnt, 1);
650
651                 ops = np->dev->netdev_ops;
652                 if (ops->ndo_netpoll_setup) {
653                         err = ops->ndo_netpoll_setup(ndev, npinfo);
654                         if (err)
655                                 goto free_npinfo;
656                 }
657         } else {
658                 npinfo = rtnl_dereference(ndev->npinfo);
659                 refcount_inc(&npinfo->refcnt);
660         }
661
662         npinfo->netpoll = np;
663
664         /* last thing to do is link it to the net device structure */
665         rcu_assign_pointer(ndev->npinfo, npinfo);
666
667         return 0;
668
669 free_npinfo:
670         kfree(npinfo);
671 out:
672         return err;
673 }
674 EXPORT_SYMBOL_GPL(__netpoll_setup);
675
676 int netpoll_setup(struct netpoll *np)
677 {
678         struct net_device *ndev = NULL, *dev = NULL;
679         struct net *net = current->nsproxy->net_ns;
680         struct in_device *in_dev;
681         int err;
682
683         rtnl_lock();
684         if (np->dev_name[0])
685                 ndev = __dev_get_by_name(net, np->dev_name);
686
687         if (!ndev) {
688                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
689                 err = -ENODEV;
690                 goto unlock;
691         }
692         dev_hold(ndev);
693
694         /* bring up DSA management network devices up first */
695         for_each_netdev(net, dev) {
696                 if (!netdev_uses_dsa(dev))
697                         continue;
698
699                 err = dev_change_flags(dev, dev->flags | IFF_UP, NULL);
700                 if (err < 0) {
701                         np_err(np, "%s failed to open %s\n",
702                                np->dev_name, dev->name);
703                         goto put;
704                 }
705         }
706
707         if (netdev_master_upper_dev_get(ndev)) {
708                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
709                 err = -EBUSY;
710                 goto put;
711         }
712
713         if (!netif_running(ndev)) {
714                 unsigned long atmost, atleast;
715
716                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
717
718                 err = dev_open(ndev, NULL);
719
720                 if (err) {
721                         np_err(np, "failed to open %s\n", ndev->name);
722                         goto put;
723                 }
724
725                 rtnl_unlock();
726                 atleast = jiffies + HZ/10;
727                 atmost = jiffies + carrier_timeout * HZ;
728                 while (!netif_carrier_ok(ndev)) {
729                         if (time_after(jiffies, atmost)) {
730                                 np_notice(np, "timeout waiting for carrier\n");
731                                 break;
732                         }
733                         msleep(1);
734                 }
735
736                 /* If carrier appears to come up instantly, we don't
737                  * trust it and pause so that we don't pump all our
738                  * queued console messages into the bitbucket.
739                  */
740
741                 if (time_before(jiffies, atleast)) {
742                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
743                         msleep(4000);
744                 }
745                 rtnl_lock();
746         }
747
748         if (!np->local_ip.ip) {
749                 if (!np->ipv6) {
750                         const struct in_ifaddr *ifa;
751
752                         in_dev = __in_dev_get_rtnl(ndev);
753                         if (!in_dev)
754                                 goto put_noaddr;
755
756                         ifa = rtnl_dereference(in_dev->ifa_list);
757                         if (!ifa) {
758 put_noaddr:
759                                 np_err(np, "no IP address for %s, aborting\n",
760                                        np->dev_name);
761                                 err = -EDESTADDRREQ;
762                                 goto put;
763                         }
764
765                         np->local_ip.ip = ifa->ifa_local;
766                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
767                 } else {
768 #if IS_ENABLED(CONFIG_IPV6)
769                         struct inet6_dev *idev;
770
771                         err = -EDESTADDRREQ;
772                         idev = __in6_dev_get(ndev);
773                         if (idev) {
774                                 struct inet6_ifaddr *ifp;
775
776                                 read_lock_bh(&idev->lock);
777                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
778                                         if (!!(ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL) !=
779                                             !!(ipv6_addr_type(&np->remote_ip.in6) & IPV6_ADDR_LINKLOCAL))
780                                                 continue;
781                                         np->local_ip.in6 = ifp->addr;
782                                         err = 0;
783                                         break;
784                                 }
785                                 read_unlock_bh(&idev->lock);
786                         }
787                         if (err) {
788                                 np_err(np, "no IPv6 address for %s, aborting\n",
789                                        np->dev_name);
790                                 goto put;
791                         } else
792                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
793 #else
794                         np_err(np, "IPv6 is not supported %s, aborting\n",
795                                np->dev_name);
796                         err = -EINVAL;
797                         goto put;
798 #endif
799                 }
800         }
801
802         /* fill up the skb queue */
803         refill_skbs();
804
805         err = __netpoll_setup(np, ndev);
806         if (err)
807                 goto put;
808
809         rtnl_unlock();
810         return 0;
811
812 put:
813         dev_put(ndev);
814 unlock:
815         rtnl_unlock();
816         return err;
817 }
818 EXPORT_SYMBOL(netpoll_setup);
819
820 static int __init netpoll_init(void)
821 {
822         skb_queue_head_init(&skb_pool);
823         return 0;
824 }
825 core_initcall(netpoll_init);
826
827 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
828 {
829         struct netpoll_info *npinfo =
830                         container_of(rcu_head, struct netpoll_info, rcu);
831
832         skb_queue_purge(&npinfo->txq);
833
834         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
835         cancel_delayed_work(&npinfo->tx_work);
836
837         /* clean after last, unfinished work */
838         __skb_queue_purge(&npinfo->txq);
839         /* now cancel it again */
840         cancel_delayed_work(&npinfo->tx_work);
841         kfree(npinfo);
842 }
843
844 void __netpoll_cleanup(struct netpoll *np)
845 {
846         struct netpoll_info *npinfo;
847
848         npinfo = rtnl_dereference(np->dev->npinfo);
849         if (!npinfo)
850                 return;
851
852         synchronize_srcu(&netpoll_srcu);
853
854         if (refcount_dec_and_test(&npinfo->refcnt)) {
855                 const struct net_device_ops *ops;
856
857                 ops = np->dev->netdev_ops;
858                 if (ops->ndo_netpoll_cleanup)
859                         ops->ndo_netpoll_cleanup(np->dev);
860
861                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
862                 call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info);
863         } else
864                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
865 }
866 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
867
868 void __netpoll_free(struct netpoll *np)
869 {
870         ASSERT_RTNL();
871
872         /* Wait for transmitting packets to finish before freeing. */
873         synchronize_rcu();
874         __netpoll_cleanup(np);
875         kfree(np);
876 }
877 EXPORT_SYMBOL_GPL(__netpoll_free);
878
879 void netpoll_cleanup(struct netpoll *np)
880 {
881         rtnl_lock();
882         if (!np->dev)
883                 goto out;
884         __netpoll_cleanup(np);
885         dev_put(np->dev);
886         np->dev = NULL;
887 out:
888         rtnl_unlock();
889 }
890 EXPORT_SYMBOL(netpoll_cleanup);