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TOMOYO Linux Cross Reference
Linux/net/core/netpoll.c

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

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