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

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.75 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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

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