net/core/netpoll.c

   1 /*
   2  * Common framework for low-level network console, dump, and debugger code
   3  *
   4  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
   5  *
   6  * based on the netconsole code from:
   7  *
   8  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
   9  * Copyright (C) 2002  Red Hat, Inc.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/moduleparam.h>
  15 #include <linux/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 #ifdef CONFIG_NETPOLL_TRAP
  50 static atomic_t trapped;
  51 #endif
  52
  53 DEFINE_STATIC_SRCU(netpoll_srcu);
  54
  55 #define USEC_PER_POLL   50
  56
  57 #define MAX_SKB_SIZE                                                    \
  58         (sizeof(struct ethhdr) +                                        \
  59          sizeof(struct iphdr) +                                         \
  60          sizeof(struct udphdr) +                                        \
  61          MAX_UDP_CHUNK)
  62
  63 static void zap_completion_queue(void);
  64 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo);
  65 static void netpoll_async_cleanup(struct work_struct *work);
  66
  67 static unsigned int carrier_timeout = 4;
  68 module_param(carrier_timeout, uint, 0644);
  69
  70 #define np_info(np, fmt, ...)                           \
  71         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  72 #define np_err(np, fmt, ...)                            \
  73         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  74 #define np_notice(np, fmt, ...)                         \
  75         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  76
  77 static void queue_process(struct work_struct *work)
  78 {
  79         struct netpoll_info *npinfo =
  80                 container_of(work, struct netpoll_info, tx_work.work);
  81         struct sk_buff *skb;
  82         unsigned long flags;
  83
  84         while ((skb = skb_dequeue(&npinfo->txq))) {
  85                 struct net_device *dev = skb->dev;
  86                 const struct net_device_ops *ops = dev->netdev_ops;
  87                 struct netdev_queue *txq;
  88
  89                 if (!netif_device_present(dev) || !netif_running(dev)) {
  90                         __kfree_skb(skb);
  91                         continue;
  92                 }
  93
  94                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  95
  96                 local_irq_save(flags);
  97                 __netif_tx_lock(txq, smp_processor_id());
  98                 if (netif_xmit_frozen_or_stopped(txq) ||
  99                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
 100                         skb_queue_head(&npinfo->txq, skb);
 101                         __netif_tx_unlock(txq);
 102                         local_irq_restore(flags);
 103
 104                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 105                         return;
 106                 }
 107                 __netif_tx_unlock(txq);
 108                 local_irq_restore(flags);
 109         }
 110 }
 111
 112 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 113                             unsigned short ulen, __be32 saddr, __be32 daddr)
 114 {
 115         __wsum psum;
 116
 117         if (uh->check == 0 || skb_csum_unnecessary(skb))
 118                 return 0;
 119
 120         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 121
 122         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 123             !csum_fold(csum_add(psum, skb->csum)))
 124                 return 0;
 125
 126         skb->csum = psum;
 127
 128         return __skb_checksum_complete(skb);
 129 }
 130
 131 /*
 132  * Check whether delayed processing was scheduled for our NIC. If so,
 133  * we attempt to grab the poll lock and use ->poll() to pump the card.
 134  * If this fails, either we've recursed in ->poll() or it's already
 135  * running on another CPU.
 136  *
 137  * Note: we don't mask interrupts with this lock because we're using
 138  * trylock here and interrupts are already disabled in the softirq
 139  * case. Further, we test the poll_owner to avoid recursion on UP
 140  * systems where the lock doesn't exist.
 141  *
 142  * In cases where there is bi-directional communications, reading only
 143  * one message at a time can lead to packets being dropped by the
 144  * network adapter, forcing superfluous retries and possibly timeouts.
 145  * Thus, we set our budget to greater than 1.
 146  */
 147 static int poll_one_napi(struct napi_struct *napi, int budget)
 148 {
 149         int work;
 150
 151         /* net_rx_action's ->poll() invocations and our's are
 152          * synchronized by this test which is only made while
 153          * holding the napi->poll_lock.
 154          */
 155         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 156                 return budget;
 157
 158         set_bit(NAPI_STATE_NPSVC, &napi->state);
 159
 160         work = napi->poll(napi, budget);
 161         WARN_ONCE(work > budget, "%pF exceeded budget in poll\n", napi->poll);
 162         trace_napi_poll(napi);
 163
 164         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 165
 166         return budget - work;
 167 }
 168
 169 static void poll_napi(struct net_device *dev, int budget)
 170 {
 171         struct napi_struct *napi;
 172
 173         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 174                 if (napi->poll_owner != smp_processor_id() &&
 175                     spin_trylock(&napi->poll_lock)) {
 176                         budget = poll_one_napi(napi, budget);
 177                         spin_unlock(&napi->poll_lock);
 178                 }
 179         }
 180 }
 181
 182 static void service_neigh_queue(struct netpoll_info *npi)
 183 {
 184         if (npi) {
 185                 struct sk_buff *skb;
 186
 187                 while ((skb = skb_dequeue(&npi->neigh_tx)))
 188                         netpoll_neigh_reply(skb, npi);
 189         }
 190 }
 191
 192 static void netpoll_poll_dev(struct net_device *dev)
 193 {
 194         const struct net_device_ops *ops;
 195         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 196         bool rx_processing = netpoll_rx_processing(ni);
 197         int budget = rx_processing? 16 : 0;
 198
 199         /* Don't do any rx activity if the dev_lock mutex is held
 200          * the dev_open/close paths use this to block netpoll activity
 201          * while changing device state
 202          */
 203         if (down_trylock(&ni->dev_lock))
 204                 return;
 205
 206         if (!netif_running(dev)) {
 207                 up(&ni->dev_lock);
 208                 return;
 209         }
 210
 211         if (rx_processing)
 212                 netpoll_set_trap(1);
 213
 214         ops = dev->netdev_ops;
 215         if (!ops->ndo_poll_controller) {
 216                 up(&ni->dev_lock);
 217                 return;
 218         }
 219
 220         /* Process pending work on NIC */
 221         ops->ndo_poll_controller(dev);
 222
 223         poll_napi(dev, budget);
 224
 225         if (rx_processing)
 226                 netpoll_set_trap(0);
 227
 228         up(&ni->dev_lock);
 229
 230         if (dev->flags & IFF_SLAVE) {
 231                 if (ni) {
 232                         struct net_device *bond_dev;
 233                         struct sk_buff *skb;
 234                         struct netpoll_info *bond_ni;
 235
 236                         bond_dev = netdev_master_upper_dev_get_rcu(dev);
 237                         bond_ni = rcu_dereference_bh(bond_dev->npinfo);
 238                         while ((skb = skb_dequeue(&ni->neigh_tx))) {
 239                                 skb->dev = bond_dev;
 240                                 skb_queue_tail(&bond_ni->neigh_tx, skb);
 241                         }
 242                 }
 243         }
 244
 245         service_neigh_queue(ni);
 246
 247         zap_completion_queue();
 248 }
 249
 250 void netpoll_rx_disable(struct net_device *dev)
 251 {
 252         struct netpoll_info *ni;
 253         int idx;
 254         might_sleep();
 255         idx = srcu_read_lock(&netpoll_srcu);
 256         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 257         if (ni)
 258                 down(&ni->dev_lock);
 259         srcu_read_unlock(&netpoll_srcu, idx);
 260 }
 261 EXPORT_SYMBOL(netpoll_rx_disable);
 262
 263 void netpoll_rx_enable(struct net_device *dev)
 264 {
 265         struct netpoll_info *ni;
 266         rcu_read_lock();
 267         ni = rcu_dereference(dev->npinfo);
 268         if (ni)
 269                 up(&ni->dev_lock);
 270         rcu_read_unlock();
 271 }
 272 EXPORT_SYMBOL(netpoll_rx_enable);
 273
 274 static void refill_skbs(void)
 275 {
 276         struct sk_buff *skb;
 277         unsigned long flags;
 278
 279         spin_lock_irqsave(&skb_pool.lock, flags);
 280         while (skb_pool.qlen < MAX_SKBS) {
 281                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 282                 if (!skb)
 283                         break;
 284
 285                 __skb_queue_tail(&skb_pool, skb);
 286         }
 287         spin_unlock_irqrestore(&skb_pool.lock, flags);
 288 }
 289
 290 static void zap_completion_queue(void)
 291 {
 292         unsigned long flags;
 293         struct softnet_data *sd = &get_cpu_var(softnet_data);
 294
 295         if (sd->completion_queue) {
 296                 struct sk_buff *clist;
 297
 298                 local_irq_save(flags);
 299                 clist = sd->completion_queue;
 300                 sd->completion_queue = NULL;
 301                 local_irq_restore(flags);
 302
 303                 while (clist != NULL) {
 304                         struct sk_buff *skb = clist;
 305                         clist = clist->next;
 306                         if (skb->destructor) {
 307                                 atomic_inc(&skb->users);
 308                                 dev_kfree_skb_any(skb); /* put this one back */
 309                         } else {
 310                                 __kfree_skb(skb);
 311                         }
 312                 }
 313         }
 314
 315         put_cpu_var(softnet_data);
 316 }
 317
 318 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 319 {
 320         int count = 0;
 321         struct sk_buff *skb;
 322
 323         zap_completion_queue();
 324         refill_skbs();
 325 repeat:
 326
 327         skb = alloc_skb(len, GFP_ATOMIC);
 328         if (!skb)
 329                 skb = skb_dequeue(&skb_pool);
 330
 331         if (!skb) {
 332                 if (++count < 10) {
 333                         netpoll_poll_dev(np->dev);
 334                         goto repeat;
 335                 }
 336                 return NULL;
 337         }
 338
 339         atomic_set(&skb->users, 1);
 340         skb_reserve(skb, reserve);
 341         return skb;
 342 }
 343
 344 static int netpoll_owner_active(struct net_device *dev)
 345 {
 346         struct napi_struct *napi;
 347
 348         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 349                 if (napi->poll_owner == smp_processor_id())
 350                         return 1;
 351         }
 352         return 0;
 353 }
 354
 355 /* call with IRQ disabled */
 356 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 357                              struct net_device *dev)
 358 {
 359         int status = NETDEV_TX_BUSY;
 360         unsigned long tries;
 361         const struct net_device_ops *ops = dev->netdev_ops;
 362         /* It is up to the caller to keep npinfo alive. */
 363         struct netpoll_info *npinfo;
 364
 365         WARN_ON_ONCE(!irqs_disabled());
 366
 367         npinfo = rcu_dereference_bh(np->dev->npinfo);
 368         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 369                 __kfree_skb(skb);
 370                 return;
 371         }
 372
 373         /* don't get messages out of order, and no recursion */
 374         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 375                 struct netdev_queue *txq;
 376
 377                 txq = netdev_pick_tx(dev, skb, NULL);
 378
 379                 /* try until next clock tick */
 380                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 381                      tries > 0; --tries) {
 382                         if (__netif_tx_trylock(txq)) {
 383                                 if (!netif_xmit_stopped(txq)) {
 384                                         if (vlan_tx_tag_present(skb) &&
 385                                             !vlan_hw_offload_capable(netif_skb_features(skb),
 386                                                                      skb->vlan_proto)) {
 387                                                 skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
 388                                                 if (unlikely(!skb)) {
 389                                                         /* This is actually a packet drop, but we
 390                                                          * don't want the code at the end of this
 391                                                          * function to try and re-queue a NULL skb.
 392                                                          */
 393                                                         status = NETDEV_TX_OK;
 394                                                         goto unlock_txq;
 395                                                 }
 396                                                 skb->vlan_tci = 0;
 397                                         }
 398
 399                                         status = ops->ndo_start_xmit(skb, dev);
 400                                         if (status == NETDEV_TX_OK)
 401                                                 txq_trans_update(txq);
 402                                 }
 403                         unlock_txq:
 404                                 __netif_tx_unlock(txq);
 405
 406                                 if (status == NETDEV_TX_OK)
 407                                         break;
 408
 409                         }
 410
 411                         /* tickle device maybe there is some cleanup */
 412                         netpoll_poll_dev(np->dev);
 413
 414                         udelay(USEC_PER_POLL);
 415                 }
 416
 417                 WARN_ONCE(!irqs_disabled(),
 418                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 419                         dev->name, ops->ndo_start_xmit);
 420
 421         }
 422
 423         if (status != NETDEV_TX_OK) {
 424                 skb_queue_tail(&npinfo->txq, skb);
 425                 schedule_delayed_work(&npinfo->tx_work,0);
 426         }
 427 }
 428 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 429
 430 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 431 {
 432         int total_len, ip_len, udp_len;
 433         struct sk_buff *skb;
 434         struct udphdr *udph;
 435         struct iphdr *iph;
 436         struct ethhdr *eth;
 437         static atomic_t ip_ident;
 438         struct ipv6hdr *ip6h;
 439
 440         udp_len = len + sizeof(*udph);
 441         if (np->ipv6)
 442                 ip_len = udp_len + sizeof(*ip6h);
 443         else
 444                 ip_len = udp_len + sizeof(*iph);
 445
 446         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 447
 448         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 449                        total_len - len);
 450         if (!skb)
 451                 return;
 452
 453         skb_copy_to_linear_data(skb, msg, len);
 454         skb_put(skb, len);
 455
 456         skb_push(skb, sizeof(*udph));
 457         skb_reset_transport_header(skb);
 458         udph = udp_hdr(skb);
 459         udph->source = htons(np->local_port);
 460         udph->dest = htons(np->remote_port);
 461         udph->len = htons(udp_len);
 462
 463         if (np->ipv6) {
 464                 udph->check = 0;
 465                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 466                                               &np->remote_ip.in6,
 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(*ip6h));
 473                 skb_reset_network_header(skb);
 474                 ip6h = ipv6_hdr(skb);
 475
 476                 /* ip6h->version = 6; ip6h->priority = 0; */
 477                 put_unaligned(0x60, (unsigned char *)ip6h);
 478                 ip6h->flow_lbl[0] = 0;
 479                 ip6h->flow_lbl[1] = 0;
 480                 ip6h->flow_lbl[2] = 0;
 481
 482                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 483                 ip6h->nexthdr = IPPROTO_UDP;
 484                 ip6h->hop_limit = 32;
 485                 ip6h->saddr = np->local_ip.in6;
 486                 ip6h->daddr = np->remote_ip.in6;
 487
 488                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 489                 skb_reset_mac_header(skb);
 490                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 491         } else {
 492                 udph->check = 0;
 493                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 494                                                 np->remote_ip.ip,
 495                                                 udp_len, IPPROTO_UDP,
 496                                                 csum_partial(udph, udp_len, 0));
 497                 if (udph->check == 0)
 498                         udph->check = CSUM_MANGLED_0;
 499
 500                 skb_push(skb, sizeof(*iph));
 501                 skb_reset_network_header(skb);
 502                 iph = ip_hdr(skb);
 503
 504                 /* iph->version = 4; iph->ihl = 5; */
 505                 put_unaligned(0x45, (unsigned char *)iph);
 506                 iph->tos      = 0;
 507                 put_unaligned(htons(ip_len), &(iph->tot_len));
 508                 iph->id       = htons(atomic_inc_return(&ip_ident));
 509                 iph->frag_off = 0;
 510                 iph->ttl      = 64;
 511                 iph->protocol = IPPROTO_UDP;
 512                 iph->check    = 0;
 513                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 514                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 515                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 516
 517                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 518                 skb_reset_mac_header(skb);
 519                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 520         }
 521
 522         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 523         ether_addr_copy(eth->h_dest, np->remote_mac);
 524
 525         skb->dev = np->dev;
 526
 527         netpoll_send_skb(np, skb);
 528 }
 529 EXPORT_SYMBOL(netpoll_send_udp);
 530
 531 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo)
 532 {
 533         int size, type = ARPOP_REPLY;
 534         __be32 sip, tip;
 535         unsigned char *sha;
 536         struct sk_buff *send_skb;
 537         struct netpoll *np, *tmp;
 538         unsigned long flags;
 539         int hlen, tlen;
 540         int hits = 0, proto;
 541
 542         if (!netpoll_rx_processing(npinfo))
 543                 return;
 544
 545         /* Before checking the packet, we do some early
 546            inspection whether this is interesting at all */
 547         spin_lock_irqsave(&npinfo->rx_lock, flags);
 548         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 549                 if (np->dev == skb->dev)
 550                         hits++;
 551         }
 552         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 553
 554         /* No netpoll struct is using this dev */
 555         if (!hits)
 556                 return;
 557
 558         proto = ntohs(eth_hdr(skb)->h_proto);
 559         if (proto == ETH_P_ARP) {
 560                 struct arphdr *arp;
 561                 unsigned char *arp_ptr;
 562                 /* No arp on this interface */
 563                 if (skb->dev->flags & IFF_NOARP)
 564                         return;
 565
 566                 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 567                         return;
 568
 569                 skb_reset_network_header(skb);
 570                 skb_reset_transport_header(skb);
 571                 arp = arp_hdr(skb);
 572
 573                 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 574                      arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 575                     arp->ar_pro != htons(ETH_P_IP) ||
 576                     arp->ar_op != htons(ARPOP_REQUEST))
 577                         return;
 578
 579                 arp_ptr = (unsigned char *)(arp+1);
 580                 /* save the location of the src hw addr */
 581                 sha = arp_ptr;
 582                 arp_ptr += skb->dev->addr_len;
 583                 memcpy(&sip, arp_ptr, 4);
 584                 arp_ptr += 4;
 585                 /* If we actually cared about dst hw addr,
 586                    it would get copied here */
 587                 arp_ptr += skb->dev->addr_len;
 588                 memcpy(&tip, arp_ptr, 4);
 589
 590                 /* Should we ignore arp? */
 591                 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 592                         return;
 593
 594                 size = arp_hdr_len(skb->dev);
 595
 596                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 597                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 598                         if (tip != np->local_ip.ip)
 599                                 continue;
 600
 601                         hlen = LL_RESERVED_SPACE(np->dev);
 602                         tlen = np->dev->needed_tailroom;
 603                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 604                         if (!send_skb)
 605                                 continue;
 606
 607                         skb_reset_network_header(send_skb);
 608                         arp = (struct arphdr *) skb_put(send_skb, size);
 609                         send_skb->dev = skb->dev;
 610                         send_skb->protocol = htons(ETH_P_ARP);
 611
 612                         /* Fill the device header for the ARP frame */
 613                         if (dev_hard_header(send_skb, skb->dev, ETH_P_ARP,
 614                                             sha, np->dev->dev_addr,
 615                                             send_skb->len) < 0) {
 616                                 kfree_skb(send_skb);
 617                                 continue;
 618                         }
 619
 620                         /*
 621                          * Fill out the arp protocol part.
 622                          *
 623                          * we only support ethernet device type,
 624                          * which (according to RFC 1390) should
 625                          * always equal 1 (Ethernet).
 626                          */
 627
 628                         arp->ar_hrd = htons(np->dev->type);
 629                         arp->ar_pro = htons(ETH_P_IP);
 630                         arp->ar_hln = np->dev->addr_len;
 631                         arp->ar_pln = 4;
 632                         arp->ar_op = htons(type);
 633
 634                         arp_ptr = (unsigned char *)(arp + 1);
 635                         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 636                         arp_ptr += np->dev->addr_len;
 637                         memcpy(arp_ptr, &tip, 4);
 638                         arp_ptr += 4;
 639                         memcpy(arp_ptr, sha, np->dev->addr_len);
 640                         arp_ptr += np->dev->addr_len;
 641                         memcpy(arp_ptr, &sip, 4);
 642
 643                         netpoll_send_skb(np, send_skb);
 644
 645                         /* If there are several rx_skb_hooks for the same
 646                          * address we're fine by sending a single reply
 647                          */
 648                         break;
 649                 }
 650                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 651         } else if( proto == ETH_P_IPV6) {
 652 #if IS_ENABLED(CONFIG_IPV6)
 653                 struct nd_msg *msg;
 654                 u8 *lladdr = NULL;
 655                 struct ipv6hdr *hdr;
 656                 struct icmp6hdr *icmp6h;
 657                 const struct in6_addr *saddr;
 658                 const struct in6_addr *daddr;
 659                 struct inet6_dev *in6_dev = NULL;
 660                 struct in6_addr *target;
 661
 662                 in6_dev = in6_dev_get(skb->dev);
 663                 if (!in6_dev || !in6_dev->cnf.accept_ra)
 664                         return;
 665
 666                 if (!pskb_may_pull(skb, skb->len))
 667                         return;
 668
 669                 msg = (struct nd_msg *)skb_transport_header(skb);
 670
 671                 __skb_push(skb, skb->data - skb_transport_header(skb));
 672
 673                 if (ipv6_hdr(skb)->hop_limit != 255)
 674                         return;
 675                 if (msg->icmph.icmp6_code != 0)
 676                         return;
 677                 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 678                         return;
 679
 680                 saddr = &ipv6_hdr(skb)->saddr;
 681                 daddr = &ipv6_hdr(skb)->daddr;
 682
 683                 size = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
 684
 685                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 686                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 687                         if (!ipv6_addr_equal(daddr, &np->local_ip.in6))
 688                                 continue;
 689
 690                         hlen = LL_RESERVED_SPACE(np->dev);
 691                         tlen = np->dev->needed_tailroom;
 692                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 693                         if (!send_skb)
 694                                 continue;
 695
 696                         send_skb->protocol = htons(ETH_P_IPV6);
 697                         send_skb->dev = skb->dev;
 698
 699                         skb_reset_network_header(send_skb);
 700                         hdr = (struct ipv6hdr *) skb_put(send_skb, sizeof(struct ipv6hdr));
 701                         *(__be32*)hdr = htonl(0x60000000);
 702                         hdr->payload_len = htons(size);
 703                         hdr->nexthdr = IPPROTO_ICMPV6;
 704                         hdr->hop_limit = 255;
 705                         hdr->saddr = *saddr;
 706                         hdr->daddr = *daddr;
 707
 708                         icmp6h = (struct icmp6hdr *) skb_put(send_skb, sizeof(struct icmp6hdr));
 709                         icmp6h->icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
 710                         icmp6h->icmp6_router = 0;
 711                         icmp6h->icmp6_solicited = 1;
 712
 713                         target = (struct in6_addr *) skb_put(send_skb, sizeof(struct in6_addr));
 714                         *target = msg->target;
 715                         icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, size,
 716                                                               IPPROTO_ICMPV6,
 717                                                               csum_partial(icmp6h,
 718                                                                            size, 0));
 719
 720                         if (dev_hard_header(send_skb, skb->dev, ETH_P_IPV6,
 721                                             lladdr, np->dev->dev_addr,
 722                                             send_skb->len) < 0) {
 723                                 kfree_skb(send_skb);
 724                                 continue;
 725                         }
 726
 727                         netpoll_send_skb(np, send_skb);
 728
 729                         /* If there are several rx_skb_hooks for the same
 730                          * address, we're fine by sending a single reply
 731                          */
 732                         break;
 733                 }
 734                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 735 #endif
 736         }
 737 }
 738
 739 static bool pkt_is_ns(struct sk_buff *skb)
 740 {
 741         struct nd_msg *msg;
 742         struct ipv6hdr *hdr;
 743
 744         if (skb->protocol != htons(ETH_P_ARP))
 745                 return false;
 746         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct nd_msg)))
 747                 return false;
 748
 749         msg = (struct nd_msg *)skb_transport_header(skb);
 750         __skb_push(skb, skb->data - skb_transport_header(skb));
 751         hdr = ipv6_hdr(skb);
 752
 753         if (hdr->nexthdr != IPPROTO_ICMPV6)
 754                 return false;
 755         if (hdr->hop_limit != 255)
 756                 return false;
 757         if (msg->icmph.icmp6_code != 0)
 758                 return false;
 759         if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 760                 return false;
 761
 762         return true;
 763 }
 764
 765 int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo)
 766 {
 767         int proto, len, ulen, data_len;
 768         int hits = 0, offset;
 769         const struct iphdr *iph;
 770         struct udphdr *uh;
 771         struct netpoll *np, *tmp;
 772         uint16_t source;
 773
 774         if (!netpoll_rx_processing(npinfo))
 775                 goto out;
 776
 777         if (skb->dev->type != ARPHRD_ETHER)
 778                 goto out;
 779
 780         /* check if netpoll clients need ARP */
 781         if (skb->protocol == htons(ETH_P_ARP) && netpoll_trap()) {
 782                 skb_queue_tail(&npinfo->neigh_tx, skb);
 783                 return 1;
 784         } else if (pkt_is_ns(skb) && netpoll_trap()) {
 785                 skb_queue_tail(&npinfo->neigh_tx, skb);
 786                 return 1;
 787         }
 788
 789         if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
 790                 skb = vlan_untag(skb);
 791                 if (unlikely(!skb))
 792                         goto out;
 793         }
 794
 795         proto = ntohs(eth_hdr(skb)->h_proto);
 796         if (proto != ETH_P_IP && proto != ETH_P_IPV6)
 797                 goto out;
 798         if (skb->pkt_type == PACKET_OTHERHOST)
 799                 goto out;
 800         if (skb_shared(skb))
 801                 goto out;
 802
 803         if (proto == ETH_P_IP) {
 804                 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 805                         goto out;
 806                 iph = (struct iphdr *)skb->data;
 807                 if (iph->ihl < 5 || iph->version != 4)
 808                         goto out;
 809                 if (!pskb_may_pull(skb, iph->ihl*4))
 810                         goto out;
 811                 iph = (struct iphdr *)skb->data;
 812                 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 813                         goto out;
 814
 815                 len = ntohs(iph->tot_len);
 816                 if (skb->len < len || len < iph->ihl*4)
 817                         goto out;
 818
 819                 /*
 820                  * Our transport medium may have padded the buffer out.
 821                  * Now We trim to the true length of the frame.
 822                  */
 823                 if (pskb_trim_rcsum(skb, len))
 824                         goto out;
 825
 826                 iph = (struct iphdr *)skb->data;
 827                 if (iph->protocol != IPPROTO_UDP)
 828                         goto out;
 829
 830                 len -= iph->ihl*4;
 831                 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 832                 offset = (unsigned char *)(uh + 1) - skb->data;
 833                 ulen = ntohs(uh->len);
 834                 data_len = skb->len - offset;
 835                 source = ntohs(uh->source);
 836
 837                 if (ulen != len)
 838                         goto out;
 839                 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 840                         goto out;
 841                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 842                         if (np->local_ip.ip && np->local_ip.ip != iph->daddr)
 843                                 continue;
 844                         if (np->remote_ip.ip && np->remote_ip.ip != iph->saddr)
 845                                 continue;
 846                         if (np->local_port && np->local_port != ntohs(uh->dest))
 847                                 continue;
 848
 849                         np->rx_skb_hook(np, source, skb, offset, data_len);
 850                         hits++;
 851                 }
 852         } else {
 853 #if IS_ENABLED(CONFIG_IPV6)
 854                 const struct ipv6hdr *ip6h;
 855
 856                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 857                         goto out;
 858                 ip6h = (struct ipv6hdr *)skb->data;
 859                 if (ip6h->version != 6)
 860                         goto out;
 861                 len = ntohs(ip6h->payload_len);
 862                 if (!len)
 863                         goto out;
 864                 if (len + sizeof(struct ipv6hdr) > skb->len)
 865                         goto out;
 866                 if (pskb_trim_rcsum(skb, len + sizeof(struct ipv6hdr)))
 867                         goto out;
 868                 ip6h = ipv6_hdr(skb);
 869                 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 870                         goto out;
 871                 uh = udp_hdr(skb);
 872                 offset = (unsigned char *)(uh + 1) - skb->data;
 873                 ulen = ntohs(uh->len);
 874                 data_len = skb->len - offset;
 875                 source = ntohs(uh->source);
 876                 if (ulen != skb->len)
 877                         goto out;
 878                 if (udp6_csum_init(skb, uh, IPPROTO_UDP))
 879                         goto out;
 880                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 881                         if (!ipv6_addr_equal(&np->local_ip.in6, &ip6h->daddr))
 882                                 continue;
 883                         if (!ipv6_addr_equal(&np->remote_ip.in6, &ip6h->saddr))
 884                                 continue;
 885                         if (np->local_port && np->local_port != ntohs(uh->dest))
 886                                 continue;
 887
 888                         np->rx_skb_hook(np, source, skb, offset, data_len);
 889                         hits++;
 890                 }
 891 #endif
 892         }
 893
 894         if (!hits)
 895                 goto out;
 896
 897         kfree_skb(skb);
 898         return 1;
 899
 900 out:
 901         if (netpoll_trap()) {
 902                 kfree_skb(skb);
 903                 return 1;
 904         }
 905
 906         return 0;
 907 }
 908
 909 void netpoll_print_options(struct netpoll *np)
 910 {
 911         np_info(np, "local port %d\n", np->local_port);
 912         if (np->ipv6)
 913                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 914         else
 915                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 916         np_info(np, "interface '%s'\n", np->dev_name);
 917         np_info(np, "remote port %d\n", np->remote_port);
 918         if (np->ipv6)
 919                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 920         else
 921                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 922         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 923 }
 924 EXPORT_SYMBOL(netpoll_print_options);
 925
 926 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 927 {
 928         const char *end;
 929
 930         if (!strchr(str, ':') &&
 931             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 932                 if (!*end)
 933                         return 0;
 934         }
 935         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 936 #if IS_ENABLED(CONFIG_IPV6)
 937                 if (!*end)
 938                         return 1;
 939 #else
 940                 return -1;
 941 #endif
 942         }
 943         return -1;
 944 }
 945
 946 int netpoll_parse_options(struct netpoll *np, char *opt)
 947 {
 948         char *cur=opt, *delim;
 949         int ipv6;
 950         bool ipversion_set = false;
 951
 952         if (*cur != '@') {
 953                 if ((delim = strchr(cur, '@')) == NULL)
 954                         goto parse_failed;
 955                 *delim = 0;
 956                 if (kstrtou16(cur, 10, &np->local_port))
 957                         goto parse_failed;
 958                 cur = delim;
 959         }
 960         cur++;
 961
 962         if (*cur != '/') {
 963                 ipversion_set = true;
 964                 if ((delim = strchr(cur, '/')) == NULL)
 965                         goto parse_failed;
 966                 *delim = 0;
 967                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 968                 if (ipv6 < 0)
 969                         goto parse_failed;
 970                 else
 971                         np->ipv6 = (bool)ipv6;
 972                 cur = delim;
 973         }
 974         cur++;
 975
 976         if (*cur != ',') {
 977                 /* parse out dev name */
 978                 if ((delim = strchr(cur, ',')) == NULL)
 979                         goto parse_failed;
 980                 *delim = 0;
 981                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 982                 cur = delim;
 983         }
 984         cur++;
 985
 986         if (*cur != '@') {
 987                 /* dst port */
 988                 if ((delim = strchr(cur, '@')) == NULL)
 989                         goto parse_failed;
 990                 *delim = 0;
 991                 if (*cur == ' ' || *cur == '\t')
 992                         np_info(np, "warning: whitespace is not allowed\n");
 993                 if (kstrtou16(cur, 10, &np->remote_port))
 994                         goto parse_failed;
 995                 cur = delim;
 996         }
 997         cur++;
 998
 999         /* dst ip */
1000         if ((delim = strchr(cur, '/')) == NULL)
1001                 goto parse_failed;
1002         *delim = 0;
1003         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
1004         if (ipv6 < 0)
1005                 goto parse_failed;
1006         else if (ipversion_set && np->ipv6 != (bool)ipv6)
1007                 goto parse_failed;
1008         else
1009                 np->ipv6 = (bool)ipv6;
1010         cur = delim + 1;
1011
1012         if (*cur != 0) {
1013                 /* MAC address */
1014                 if (!mac_pton(cur, np->remote_mac))
1015                         goto parse_failed;
1016         }
1017
1018         netpoll_print_options(np);
1019
1020         return 0;
1021
1022  parse_failed:
1023         np_info(np, "couldn't parse config at '%s'!\n", cur);
1024         return -1;
1025 }
1026 EXPORT_SYMBOL(netpoll_parse_options);
1027
1028 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
1029 {
1030         struct netpoll_info *npinfo;
1031         const struct net_device_ops *ops;
1032         unsigned long flags;
1033         int err;
1034
1035         np->dev = ndev;
1036         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
1037         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
1038
1039         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
1040             !ndev->netdev_ops->ndo_poll_controller) {
1041                 np_err(np, "%s doesn't support polling, aborting\n",
1042                        np->dev_name);
1043                 err = -ENOTSUPP;
1044                 goto out;
1045         }
1046
1047         if (!ndev->npinfo) {
1048                 npinfo = kmalloc(sizeof(*npinfo), gfp);
1049                 if (!npinfo) {
1050                         err = -ENOMEM;
1051                         goto out;
1052                 }
1053
1054                 INIT_LIST_HEAD(&npinfo->rx_np);
1055
1056                 spin_lock_init(&npinfo->rx_lock);
1057                 sema_init(&npinfo->dev_lock, 1);
1058                 skb_queue_head_init(&npinfo->neigh_tx);
1059                 skb_queue_head_init(&npinfo->txq);
1060                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
1061
1062                 atomic_set(&npinfo->refcnt, 1);
1063
1064                 ops = np->dev->netdev_ops;
1065                 if (ops->ndo_netpoll_setup) {
1066                         err = ops->ndo_netpoll_setup(ndev, npinfo, gfp);
1067                         if (err)
1068                                 goto free_npinfo;
1069                 }
1070         } else {
1071                 npinfo = rtnl_dereference(ndev->npinfo);
1072                 atomic_inc(&npinfo->refcnt);
1073         }
1074
1075         npinfo->netpoll = np;
1076
1077         if (np->rx_skb_hook) {
1078                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1079                 list_add_tail(&np->rx, &npinfo->rx_np);
1080                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1081         }
1082
1083         /* last thing to do is link it to the net device structure */
1084         rcu_assign_pointer(ndev->npinfo, npinfo);
1085
1086         return 0;
1087
1088 free_npinfo:
1089         kfree(npinfo);
1090 out:
1091         return err;
1092 }
1093 EXPORT_SYMBOL_GPL(__netpoll_setup);
1094
1095 int netpoll_setup(struct netpoll *np)
1096 {
1097         struct net_device *ndev = NULL;
1098         struct in_device *in_dev;
1099         int err;
1100
1101         rtnl_lock();
1102         if (np->dev_name) {
1103                 struct net *net = current->nsproxy->net_ns;
1104                 ndev = __dev_get_by_name(net, np->dev_name);
1105         }
1106         if (!ndev) {
1107                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
1108                 err = -ENODEV;
1109                 goto unlock;
1110         }
1111         dev_hold(ndev);
1112
1113         if (netdev_master_upper_dev_get(ndev)) {
1114                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
1115                 err = -EBUSY;
1116                 goto put;
1117         }
1118
1119         if (!netif_running(ndev)) {
1120                 unsigned long atmost, atleast;
1121
1122                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
1123
1124                 err = dev_open(ndev);
1125
1126                 if (err) {
1127                         np_err(np, "failed to open %s\n", ndev->name);
1128                         goto put;
1129                 }
1130
1131                 rtnl_unlock();
1132                 atleast = jiffies + HZ/10;
1133                 atmost = jiffies + carrier_timeout * HZ;
1134                 while (!netif_carrier_ok(ndev)) {
1135                         if (time_after(jiffies, atmost)) {
1136                                 np_notice(np, "timeout waiting for carrier\n");
1137                                 break;
1138                         }
1139                         msleep(1);
1140                 }
1141
1142                 /* If carrier appears to come up instantly, we don't
1143                  * trust it and pause so that we don't pump all our
1144                  * queued console messages into the bitbucket.
1145                  */
1146
1147                 if (time_before(jiffies, atleast)) {
1148                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
1149                         msleep(4000);
1150                 }
1151                 rtnl_lock();
1152         }
1153
1154         if (!np->local_ip.ip) {
1155                 if (!np->ipv6) {
1156                         in_dev = __in_dev_get_rtnl(ndev);
1157
1158                         if (!in_dev || !in_dev->ifa_list) {
1159                                 np_err(np, "no IP address for %s, aborting\n",
1160                                        np->dev_name);
1161                                 err = -EDESTADDRREQ;
1162                                 goto put;
1163                         }
1164
1165                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
1166                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
1167                 } else {
1168 #if IS_ENABLED(CONFIG_IPV6)
1169                         struct inet6_dev *idev;
1170
1171                         err = -EDESTADDRREQ;
1172                         idev = __in6_dev_get(ndev);
1173                         if (idev) {
1174                                 struct inet6_ifaddr *ifp;
1175
1176                                 read_lock_bh(&idev->lock);
1177                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
1178                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
1179                                                 continue;
1180                                         np->local_ip.in6 = ifp->addr;
1181                                         err = 0;
1182                                         break;
1183                                 }
1184                                 read_unlock_bh(&idev->lock);
1185                         }
1186                         if (err) {
1187                                 np_err(np, "no IPv6 address for %s, aborting\n",
1188                                        np->dev_name);
1189                                 goto put;
1190                         } else
1191                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
1192 #else
1193                         np_err(np, "IPv6 is not supported %s, aborting\n",
1194                                np->dev_name);
1195                         err = -EINVAL;
1196                         goto put;
1197 #endif
1198                 }
1199         }
1200
1201         /* fill up the skb queue */
1202         refill_skbs();
1203
1204         err = __netpoll_setup(np, ndev, GFP_KERNEL);
1205         if (err)
1206                 goto put;
1207
1208         rtnl_unlock();
1209         return 0;
1210
1211 put:
1212         dev_put(ndev);
1213 unlock:
1214         rtnl_unlock();
1215         return err;
1216 }
1217 EXPORT_SYMBOL(netpoll_setup);
1218
1219 static int __init netpoll_init(void)
1220 {
1221         skb_queue_head_init(&skb_pool);
1222         return 0;
1223 }
1224 core_initcall(netpoll_init);
1225
1226 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
1227 {
1228         struct netpoll_info *npinfo =
1229                         container_of(rcu_head, struct netpoll_info, rcu);
1230
1231         skb_queue_purge(&npinfo->neigh_tx);
1232         skb_queue_purge(&npinfo->txq);
1233
1234         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
1235         cancel_delayed_work(&npinfo->tx_work);
1236
1237         /* clean after last, unfinished work */
1238         __skb_queue_purge(&npinfo->txq);
1239         /* now cancel it again */
1240         cancel_delayed_work(&npinfo->tx_work);
1241         kfree(npinfo);
1242 }
1243
1244 void __netpoll_cleanup(struct netpoll *np)
1245 {
1246         struct netpoll_info *npinfo;
1247         unsigned long flags;
1248
1249         /* rtnl_dereference would be preferable here but
1250          * rcu_cleanup_netpoll path can put us in here safely without
1251          * holding the rtnl, so plain rcu_dereference it is
1252          */
1253         npinfo = rtnl_dereference(np->dev->npinfo);
1254         if (!npinfo)
1255                 return;
1256
1257         if (!list_empty(&npinfo->rx_np)) {
1258                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1259                 list_del(&np->rx);
1260                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1261         }
1262
1263         synchronize_srcu(&netpoll_srcu);
1264
1265         if (atomic_dec_and_test(&npinfo->refcnt)) {
1266                 const struct net_device_ops *ops;
1267
1268                 ops = np->dev->netdev_ops;
1269                 if (ops->ndo_netpoll_cleanup)
1270                         ops->ndo_netpoll_cleanup(np->dev);
1271
1272                 rcu_assign_pointer(np->dev->npinfo, NULL);
1273                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
1274         }
1275 }
1276 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
1277
1278 static void netpoll_async_cleanup(struct work_struct *work)
1279 {
1280         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
1281
1282         rtnl_lock();
1283         __netpoll_cleanup(np);
1284         rtnl_unlock();
1285         kfree(np);
1286 }
1287
1288 void __netpoll_free_async(struct netpoll *np)
1289 {
1290         schedule_work(&np->cleanup_work);
1291 }
1292 EXPORT_SYMBOL_GPL(__netpoll_free_async);
1293
1294 void netpoll_cleanup(struct netpoll *np)
1295 {
1296         rtnl_lock();
1297         if (!np->dev)
1298                 goto out;
1299         __netpoll_cleanup(np);
1300         dev_put(np->dev);
1301         np->dev = NULL;
1302 out:
1303         rtnl_unlock();
1304 }
1305 EXPORT_SYMBOL(netpoll_cleanup);
1306
1307 #ifdef CONFIG_NETPOLL_TRAP
1308 int netpoll_trap(void)
1309 {
1310         return atomic_read(&trapped);
1311 }
1312 EXPORT_SYMBOL(netpoll_trap);
1313
1314 void netpoll_set_trap(int trap)
1315 {
1316         if (trap)
1317                 atomic_inc(&trapped);
1318         else
1319                 atomic_dec(&trapped);
1320 }
1321 EXPORT_SYMBOL(netpoll_set_trap);
1322 #endif /* CONFIG_NETPOLL_TRAP */