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 static atomic_t trapped;
  50
  51 DEFINE_STATIC_SRCU(netpoll_srcu);
  52
  53 #define USEC_PER_POLL   50
  54 #define NETPOLL_RX_ENABLED  1
  55 #define NETPOLL_RX_DROP     2
  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 netpoll_info *npinfo,
 148                          struct napi_struct *napi, int budget)
 149 {
 150         int work;
 151
 152         /* net_rx_action's ->poll() invocations and our's are
 153          * synchronized by this test which is only made while
 154          * holding the napi->poll_lock.
 155          */
 156         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 157                 return budget;
 158
 159         npinfo->rx_flags |= NETPOLL_RX_DROP;
 160         atomic_inc(&trapped);
 161         set_bit(NAPI_STATE_NPSVC, &napi->state);
 162
 163         work = napi->poll(napi, budget);
 164         trace_napi_poll(napi);
 165
 166         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 167         atomic_dec(&trapped);
 168         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 169
 170         return budget - work;
 171 }
 172
 173 static void poll_napi(struct net_device *dev)
 174 {
 175         struct napi_struct *napi;
 176         int budget = 16;
 177
 178         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 179                 if (napi->poll_owner != smp_processor_id() &&
 180                     spin_trylock(&napi->poll_lock)) {
 181                         budget = poll_one_napi(rcu_dereference_bh(dev->npinfo),
 182                                                napi, budget);
 183                         spin_unlock(&napi->poll_lock);
 184
 185                         if (!budget)
 186                                 break;
 187                 }
 188         }
 189 }
 190
 191 static void service_neigh_queue(struct netpoll_info *npi)
 192 {
 193         if (npi) {
 194                 struct sk_buff *skb;
 195
 196                 while ((skb = skb_dequeue(&npi->neigh_tx)))
 197                         netpoll_neigh_reply(skb, npi);
 198         }
 199 }
 200
 201 static void netpoll_poll_dev(struct net_device *dev)
 202 {
 203         const struct net_device_ops *ops;
 204         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 205
 206         /* Don't do any rx activity if the dev_lock mutex is held
 207          * the dev_open/close paths use this to block netpoll activity
 208          * while changing device state
 209          */
 210         if (down_trylock(&ni->dev_lock))
 211                 return;
 212
 213         if (!netif_running(dev)) {
 214                 up(&ni->dev_lock);
 215                 return;
 216         }
 217
 218         ops = dev->netdev_ops;
 219         if (!ops->ndo_poll_controller) {
 220                 up(&ni->dev_lock);
 221                 return;
 222         }
 223
 224         /* Process pending work on NIC */
 225         ops->ndo_poll_controller(dev);
 226
 227         poll_napi(dev);
 228
 229         up(&ni->dev_lock);
 230
 231         if (dev->flags & IFF_SLAVE) {
 232                 if (ni) {
 233                         struct net_device *bond_dev;
 234                         struct sk_buff *skb;
 235                         struct netpoll_info *bond_ni;
 236
 237                         bond_dev = netdev_master_upper_dev_get_rcu(dev);
 238                         bond_ni = rcu_dereference_bh(bond_dev->npinfo);
 239                         while ((skb = skb_dequeue(&ni->neigh_tx))) {
 240                                 skb->dev = bond_dev;
 241                                 skb_queue_tail(&bond_ni->neigh_tx, skb);
 242                         }
 243                 }
 244         }
 245
 246         service_neigh_queue(ni);
 247
 248         zap_completion_queue();
 249 }
 250
 251 int netpoll_rx_disable(struct net_device *dev)
 252 {
 253         struct netpoll_info *ni;
 254         int idx;
 255         might_sleep();
 256         idx = srcu_read_lock(&netpoll_srcu);
 257         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 258         if (ni)
 259                 down(&ni->dev_lock);
 260         srcu_read_unlock(&netpoll_srcu, idx);
 261         return 0;
 262 }
 263 EXPORT_SYMBOL(netpoll_rx_disable);
 264
 265 void netpoll_rx_enable(struct net_device *dev)
 266 {
 267         struct netpoll_info *ni;
 268         rcu_read_lock();
 269         ni = rcu_dereference(dev->npinfo);
 270         if (ni)
 271                 up(&ni->dev_lock);
 272         rcu_read_unlock();
 273 }
 274 EXPORT_SYMBOL(netpoll_rx_enable);
 275
 276 static void refill_skbs(void)
 277 {
 278         struct sk_buff *skb;
 279         unsigned long flags;
 280
 281         spin_lock_irqsave(&skb_pool.lock, flags);
 282         while (skb_pool.qlen < MAX_SKBS) {
 283                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 284                 if (!skb)
 285                         break;
 286
 287                 __skb_queue_tail(&skb_pool, skb);
 288         }
 289         spin_unlock_irqrestore(&skb_pool.lock, flags);
 290 }
 291
 292 static void zap_completion_queue(void)
 293 {
 294         unsigned long flags;
 295         struct softnet_data *sd = &get_cpu_var(softnet_data);
 296
 297         if (sd->completion_queue) {
 298                 struct sk_buff *clist;
 299
 300                 local_irq_save(flags);
 301                 clist = sd->completion_queue;
 302                 sd->completion_queue = NULL;
 303                 local_irq_restore(flags);
 304
 305                 while (clist != NULL) {
 306                         struct sk_buff *skb = clist;
 307                         clist = clist->next;
 308                         if (skb->destructor) {
 309                                 atomic_inc(&skb->users);
 310                                 dev_kfree_skb_any(skb); /* put this one back */
 311                         } else {
 312                                 __kfree_skb(skb);
 313                         }
 314                 }
 315         }
 316
 317         put_cpu_var(softnet_data);
 318 }
 319
 320 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 321 {
 322         int count = 0;
 323         struct sk_buff *skb;
 324
 325         zap_completion_queue();
 326         refill_skbs();
 327 repeat:
 328
 329         skb = alloc_skb(len, GFP_ATOMIC);
 330         if (!skb)
 331                 skb = skb_dequeue(&skb_pool);
 332
 333         if (!skb) {
 334                 if (++count < 10) {
 335                         netpoll_poll_dev(np->dev);
 336                         goto repeat;
 337                 }
 338                 return NULL;
 339         }
 340
 341         atomic_set(&skb->users, 1);
 342         skb_reserve(skb, reserve);
 343         return skb;
 344 }
 345
 346 static int netpoll_owner_active(struct net_device *dev)
 347 {
 348         struct napi_struct *napi;
 349
 350         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 351                 if (napi->poll_owner == smp_processor_id())
 352                         return 1;
 353         }
 354         return 0;
 355 }
 356
 357 /* call with IRQ disabled */
 358 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 359                              struct net_device *dev)
 360 {
 361         int status = NETDEV_TX_BUSY;
 362         unsigned long tries;
 363         const struct net_device_ops *ops = dev->netdev_ops;
 364         /* It is up to the caller to keep npinfo alive. */
 365         struct netpoll_info *npinfo;
 366
 367         WARN_ON_ONCE(!irqs_disabled());
 368
 369         npinfo = rcu_dereference_bh(np->dev->npinfo);
 370         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 371                 __kfree_skb(skb);
 372                 return;
 373         }
 374
 375         /* don't get messages out of order, and no recursion */
 376         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 377                 struct netdev_queue *txq;
 378
 379                 txq = netdev_pick_tx(dev, skb);
 380
 381                 /* try until next clock tick */
 382                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 383                      tries > 0; --tries) {
 384                         if (__netif_tx_trylock(txq)) {
 385                                 if (!netif_xmit_stopped(txq)) {
 386                                         if (vlan_tx_tag_present(skb) &&
 387                                             !vlan_hw_offload_capable(netif_skb_features(skb),
 388                                                                      skb->vlan_proto)) {
 389                                                 skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
 390                                                 if (unlikely(!skb))
 391                                                         break;
 392                                                 skb->vlan_tci = 0;
 393                                         }
 394
 395                                         status = ops->ndo_start_xmit(skb, dev);
 396                                         if (status == NETDEV_TX_OK)
 397                                                 txq_trans_update(txq);
 398                                 }
 399                                 __netif_tx_unlock(txq);
 400
 401                                 if (status == NETDEV_TX_OK)
 402                                         break;
 403
 404                         }
 405
 406                         /* tickle device maybe there is some cleanup */
 407                         netpoll_poll_dev(np->dev);
 408
 409                         udelay(USEC_PER_POLL);
 410                 }
 411
 412                 WARN_ONCE(!irqs_disabled(),
 413                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 414                         dev->name, ops->ndo_start_xmit);
 415
 416         }
 417
 418         if (status != NETDEV_TX_OK) {
 419                 skb_queue_tail(&npinfo->txq, skb);
 420                 schedule_delayed_work(&npinfo->tx_work,0);
 421         }
 422 }
 423 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 424
 425 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 426 {
 427         int total_len, ip_len, udp_len;
 428         struct sk_buff *skb;
 429         struct udphdr *udph;
 430         struct iphdr *iph;
 431         struct ethhdr *eth;
 432         static atomic_t ip_ident;
 433         struct ipv6hdr *ip6h;
 434
 435         udp_len = len + sizeof(*udph);
 436         if (np->ipv6)
 437                 ip_len = udp_len + sizeof(*ip6h);
 438         else
 439                 ip_len = udp_len + sizeof(*iph);
 440
 441         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 442
 443         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 444                        total_len - len);
 445         if (!skb)
 446                 return;
 447
 448         skb_copy_to_linear_data(skb, msg, len);
 449         skb_put(skb, len);
 450
 451         skb_push(skb, sizeof(*udph));
 452         skb_reset_transport_header(skb);
 453         udph = udp_hdr(skb);
 454         udph->source = htons(np->local_port);
 455         udph->dest = htons(np->remote_port);
 456         udph->len = htons(udp_len);
 457
 458         if (np->ipv6) {
 459                 udph->check = 0;
 460                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 461                                               &np->remote_ip.in6,
 462                                               udp_len, IPPROTO_UDP,
 463                                               csum_partial(udph, udp_len, 0));
 464                 if (udph->check == 0)
 465                         udph->check = CSUM_MANGLED_0;
 466
 467                 skb_push(skb, sizeof(*ip6h));
 468                 skb_reset_network_header(skb);
 469                 ip6h = ipv6_hdr(skb);
 470
 471                 /* ip6h->version = 6; ip6h->priority = 0; */
 472                 put_unaligned(0x60, (unsigned char *)ip6h);
 473                 ip6h->flow_lbl[0] = 0;
 474                 ip6h->flow_lbl[1] = 0;
 475                 ip6h->flow_lbl[2] = 0;
 476
 477                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 478                 ip6h->nexthdr = IPPROTO_UDP;
 479                 ip6h->hop_limit = 32;
 480                 ip6h->saddr = np->local_ip.in6;
 481                 ip6h->daddr = np->remote_ip.in6;
 482
 483                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 484                 skb_reset_mac_header(skb);
 485                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 486         } else {
 487                 udph->check = 0;
 488                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 489                                                 np->remote_ip.ip,
 490                                                 udp_len, IPPROTO_UDP,
 491                                                 csum_partial(udph, udp_len, 0));
 492                 if (udph->check == 0)
 493                         udph->check = CSUM_MANGLED_0;
 494
 495                 skb_push(skb, sizeof(*iph));
 496                 skb_reset_network_header(skb);
 497                 iph = ip_hdr(skb);
 498
 499                 /* iph->version = 4; iph->ihl = 5; */
 500                 put_unaligned(0x45, (unsigned char *)iph);
 501                 iph->tos      = 0;
 502                 put_unaligned(htons(ip_len), &(iph->tot_len));
 503                 iph->id       = htons(atomic_inc_return(&ip_ident));
 504                 iph->frag_off = 0;
 505                 iph->ttl      = 64;
 506                 iph->protocol = IPPROTO_UDP;
 507                 iph->check    = 0;
 508                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 509                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 510                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 511
 512                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 513                 skb_reset_mac_header(skb);
 514                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 515         }
 516
 517         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 518         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 519
 520         skb->dev = np->dev;
 521
 522         netpoll_send_skb(np, skb);
 523 }
 524 EXPORT_SYMBOL(netpoll_send_udp);
 525
 526 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo)
 527 {
 528         int size, type = ARPOP_REPLY;
 529         __be32 sip, tip;
 530         unsigned char *sha;
 531         struct sk_buff *send_skb;
 532         struct netpoll *np, *tmp;
 533         unsigned long flags;
 534         int hlen, tlen;
 535         int hits = 0, proto;
 536
 537         if (list_empty(&npinfo->rx_np))
 538                 return;
 539
 540         /* Before checking the packet, we do some early
 541            inspection whether this is interesting at all */
 542         spin_lock_irqsave(&npinfo->rx_lock, flags);
 543         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 544                 if (np->dev == skb->dev)
 545                         hits++;
 546         }
 547         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 548
 549         /* No netpoll struct is using this dev */
 550         if (!hits)
 551                 return;
 552
 553         proto = ntohs(eth_hdr(skb)->h_proto);
 554         if (proto == ETH_P_IP) {
 555                 struct arphdr *arp;
 556                 unsigned char *arp_ptr;
 557                 /* No arp on this interface */
 558                 if (skb->dev->flags & IFF_NOARP)
 559                         return;
 560
 561                 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 562                         return;
 563
 564                 skb_reset_network_header(skb);
 565                 skb_reset_transport_header(skb);
 566                 arp = arp_hdr(skb);
 567
 568                 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 569                      arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 570                     arp->ar_pro != htons(ETH_P_IP) ||
 571                     arp->ar_op != htons(ARPOP_REQUEST))
 572                         return;
 573
 574                 arp_ptr = (unsigned char *)(arp+1);
 575                 /* save the location of the src hw addr */
 576                 sha = arp_ptr;
 577                 arp_ptr += skb->dev->addr_len;
 578                 memcpy(&sip, arp_ptr, 4);
 579                 arp_ptr += 4;
 580                 /* If we actually cared about dst hw addr,
 581                    it would get copied here */
 582                 arp_ptr += skb->dev->addr_len;
 583                 memcpy(&tip, arp_ptr, 4);
 584
 585                 /* Should we ignore arp? */
 586                 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 587                         return;
 588
 589                 size = arp_hdr_len(skb->dev);
 590
 591                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 592                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 593                         if (tip != np->local_ip.ip)
 594                                 continue;
 595
 596                         hlen = LL_RESERVED_SPACE(np->dev);
 597                         tlen = np->dev->needed_tailroom;
 598                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 599                         if (!send_skb)
 600                                 continue;
 601
 602                         skb_reset_network_header(send_skb);
 603                         arp = (struct arphdr *) skb_put(send_skb, size);
 604                         send_skb->dev = skb->dev;
 605                         send_skb->protocol = htons(ETH_P_ARP);
 606
 607                         /* Fill the device header for the ARP frame */
 608                         if (dev_hard_header(send_skb, skb->dev, ETH_P_ARP,
 609                                             sha, np->dev->dev_addr,
 610                                             send_skb->len) < 0) {
 611                                 kfree_skb(send_skb);
 612                                 continue;
 613                         }
 614
 615                         /*
 616                          * Fill out the arp protocol part.
 617                          *
 618                          * we only support ethernet device type,
 619                          * which (according to RFC 1390) should
 620                          * always equal 1 (Ethernet).
 621                          */
 622
 623                         arp->ar_hrd = htons(np->dev->type);
 624                         arp->ar_pro = htons(ETH_P_IP);
 625                         arp->ar_hln = np->dev->addr_len;
 626                         arp->ar_pln = 4;
 627                         arp->ar_op = htons(type);
 628
 629                         arp_ptr = (unsigned char *)(arp + 1);
 630                         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 631                         arp_ptr += np->dev->addr_len;
 632                         memcpy(arp_ptr, &tip, 4);
 633                         arp_ptr += 4;
 634                         memcpy(arp_ptr, sha, np->dev->addr_len);
 635                         arp_ptr += np->dev->addr_len;
 636                         memcpy(arp_ptr, &sip, 4);
 637
 638                         netpoll_send_skb(np, send_skb);
 639
 640                         /* If there are several rx_hooks for the same address,
 641                            we're fine by sending a single reply */
 642                         break;
 643                 }
 644                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 645         } else if( proto == ETH_P_IPV6) {
 646 #if IS_ENABLED(CONFIG_IPV6)
 647                 struct nd_msg *msg;
 648                 u8 *lladdr = NULL;
 649                 struct ipv6hdr *hdr;
 650                 struct icmp6hdr *icmp6h;
 651                 const struct in6_addr *saddr;
 652                 const struct in6_addr *daddr;
 653                 struct inet6_dev *in6_dev = NULL;
 654                 struct in6_addr *target;
 655
 656                 in6_dev = in6_dev_get(skb->dev);
 657                 if (!in6_dev || !in6_dev->cnf.accept_ra)
 658                         return;
 659
 660                 if (!pskb_may_pull(skb, skb->len))
 661                         return;
 662
 663                 msg = (struct nd_msg *)skb_transport_header(skb);
 664
 665                 __skb_push(skb, skb->data - skb_transport_header(skb));
 666
 667                 if (ipv6_hdr(skb)->hop_limit != 255)
 668                         return;
 669                 if (msg->icmph.icmp6_code != 0)
 670                         return;
 671                 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 672                         return;
 673
 674                 saddr = &ipv6_hdr(skb)->saddr;
 675                 daddr = &ipv6_hdr(skb)->daddr;
 676
 677                 size = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
 678
 679                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 680                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 681                         if (!ipv6_addr_equal(daddr, &np->local_ip.in6))
 682                                 continue;
 683
 684                         hlen = LL_RESERVED_SPACE(np->dev);
 685                         tlen = np->dev->needed_tailroom;
 686                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 687                         if (!send_skb)
 688                                 continue;
 689
 690                         send_skb->protocol = htons(ETH_P_IPV6);
 691                         send_skb->dev = skb->dev;
 692
 693                         skb_reset_network_header(send_skb);
 694                         skb_put(send_skb, sizeof(struct ipv6hdr));
 695                         hdr = ipv6_hdr(send_skb);
 696
 697                         *(__be32*)hdr = htonl(0x60000000);
 698
 699                         hdr->payload_len = htons(size);
 700                         hdr->nexthdr = IPPROTO_ICMPV6;
 701                         hdr->hop_limit = 255;
 702                         hdr->saddr = *saddr;
 703                         hdr->daddr = *daddr;
 704
 705                         send_skb->transport_header = send_skb->tail;
 706                         skb_put(send_skb, size);
 707
 708                         icmp6h = (struct icmp6hdr *)skb_transport_header(skb);
 709                         icmp6h->icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
 710                         icmp6h->icmp6_router = 0;
 711                         icmp6h->icmp6_solicited = 1;
 712                         target = (struct in6_addr *)(skb_transport_header(send_skb) + sizeof(struct icmp6hdr));
 713                         *target = msg->target;
 714                         icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, size,
 715                                                               IPPROTO_ICMPV6,
 716                                                               csum_partial(icmp6h,
 717                                                                            size, 0));
 718
 719                         if (dev_hard_header(send_skb, skb->dev, ETH_P_IPV6,
 720                                             lladdr, np->dev->dev_addr,
 721                                             send_skb->len) < 0) {
 722                                 kfree_skb(send_skb);
 723                                 continue;
 724                         }
 725
 726                         netpoll_send_skb(np, send_skb);
 727
 728                         /* If there are several rx_hooks for the same address,
 729                            we're fine by sending a single reply */
 730                         break;
 731                 }
 732                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 733 #endif
 734         }
 735 }
 736
 737 static bool pkt_is_ns(struct sk_buff *skb)
 738 {
 739         struct nd_msg *msg;
 740         struct ipv6hdr *hdr;
 741
 742         if (skb->protocol != htons(ETH_P_ARP))
 743                 return false;
 744         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct nd_msg)))
 745                 return false;
 746
 747         msg = (struct nd_msg *)skb_transport_header(skb);
 748         __skb_push(skb, skb->data - skb_transport_header(skb));
 749         hdr = ipv6_hdr(skb);
 750
 751         if (hdr->nexthdr != IPPROTO_ICMPV6)
 752                 return false;
 753         if (hdr->hop_limit != 255)
 754                 return false;
 755         if (msg->icmph.icmp6_code != 0)
 756                 return false;
 757         if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 758                 return false;
 759
 760         return true;
 761 }
 762
 763 int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo)
 764 {
 765         int proto, len, ulen;
 766         int hits = 0;
 767         const struct iphdr *iph;
 768         struct udphdr *uh;
 769         struct netpoll *np, *tmp;
 770
 771         if (list_empty(&npinfo->rx_np))
 772                 goto out;
 773
 774         if (skb->dev->type != ARPHRD_ETHER)
 775                 goto out;
 776
 777         /* check if netpoll clients need ARP */
 778         if (skb->protocol == htons(ETH_P_ARP) && atomic_read(&trapped)) {
 779                 skb_queue_tail(&npinfo->neigh_tx, skb);
 780                 return 1;
 781         } else if (pkt_is_ns(skb) && atomic_read(&trapped)) {
 782                 skb_queue_tail(&npinfo->neigh_tx, skb);
 783                 return 1;
 784         }
 785
 786         if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
 787                 skb = vlan_untag(skb);
 788                 if (unlikely(!skb))
 789                         goto out;
 790         }
 791
 792         proto = ntohs(eth_hdr(skb)->h_proto);
 793         if (proto != ETH_P_IP && proto != ETH_P_IPV6)
 794                 goto out;
 795         if (skb->pkt_type == PACKET_OTHERHOST)
 796                 goto out;
 797         if (skb_shared(skb))
 798                 goto out;
 799
 800         if (proto == ETH_P_IP) {
 801                 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 802                         goto out;
 803                 iph = (struct iphdr *)skb->data;
 804                 if (iph->ihl < 5 || iph->version != 4)
 805                         goto out;
 806                 if (!pskb_may_pull(skb, iph->ihl*4))
 807                         goto out;
 808                 iph = (struct iphdr *)skb->data;
 809                 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 810                         goto out;
 811
 812                 len = ntohs(iph->tot_len);
 813                 if (skb->len < len || len < iph->ihl*4)
 814                         goto out;
 815
 816                 /*
 817                  * Our transport medium may have padded the buffer out.
 818                  * Now We trim to the true length of the frame.
 819                  */
 820                 if (pskb_trim_rcsum(skb, len))
 821                         goto out;
 822
 823                 iph = (struct iphdr *)skb->data;
 824                 if (iph->protocol != IPPROTO_UDP)
 825                         goto out;
 826
 827                 len -= iph->ihl*4;
 828                 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 829                 ulen = ntohs(uh->len);
 830
 831                 if (ulen != len)
 832                         goto out;
 833                 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 834                         goto out;
 835                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 836                         if (np->local_ip.ip && np->local_ip.ip != iph->daddr)
 837                                 continue;
 838                         if (np->remote_ip.ip && np->remote_ip.ip != iph->saddr)
 839                                 continue;
 840                         if (np->local_port && np->local_port != ntohs(uh->dest))
 841                                 continue;
 842
 843                         np->rx_hook(np, ntohs(uh->source),
 844                                        (char *)(uh+1),
 845                                        ulen - sizeof(struct udphdr));
 846                         hits++;
 847                 }
 848         } else {
 849 #if IS_ENABLED(CONFIG_IPV6)
 850                 const struct ipv6hdr *ip6h;
 851
 852                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 853                         goto out;
 854                 ip6h = (struct ipv6hdr *)skb->data;
 855                 if (ip6h->version != 6)
 856                         goto out;
 857                 len = ntohs(ip6h->payload_len);
 858                 if (!len)
 859                         goto out;
 860                 if (len + sizeof(struct ipv6hdr) > skb->len)
 861                         goto out;
 862                 if (pskb_trim_rcsum(skb, len + sizeof(struct ipv6hdr)))
 863                         goto out;
 864                 ip6h = ipv6_hdr(skb);
 865                 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 866                         goto out;
 867                 uh = udp_hdr(skb);
 868                 ulen = ntohs(uh->len);
 869                 if (ulen != skb->len)
 870                         goto out;
 871                 if (udp6_csum_init(skb, uh, IPPROTO_UDP))
 872                         goto out;
 873                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 874                         if (!ipv6_addr_equal(&np->local_ip.in6, &ip6h->daddr))
 875                                 continue;
 876                         if (!ipv6_addr_equal(&np->remote_ip.in6, &ip6h->saddr))
 877                                 continue;
 878                         if (np->local_port && np->local_port != ntohs(uh->dest))
 879                                 continue;
 880
 881                         np->rx_hook(np, ntohs(uh->source),
 882                                        (char *)(uh+1),
 883                                        ulen - sizeof(struct udphdr));
 884                         hits++;
 885                 }
 886 #endif
 887         }
 888
 889         if (!hits)
 890                 goto out;
 891
 892         kfree_skb(skb);
 893         return 1;
 894
 895 out:
 896         if (atomic_read(&trapped)) {
 897                 kfree_skb(skb);
 898                 return 1;
 899         }
 900
 901         return 0;
 902 }
 903
 904 void netpoll_print_options(struct netpoll *np)
 905 {
 906         np_info(np, "local port %d\n", np->local_port);
 907         if (np->ipv6)
 908                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 909         else
 910                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 911         np_info(np, "interface '%s'\n", np->dev_name);
 912         np_info(np, "remote port %d\n", np->remote_port);
 913         if (np->ipv6)
 914                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 915         else
 916                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 917         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 918 }
 919 EXPORT_SYMBOL(netpoll_print_options);
 920
 921 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 922 {
 923         const char *end;
 924
 925         if (!strchr(str, ':') &&
 926             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 927                 if (!*end)
 928                         return 0;
 929         }
 930         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 931 #if IS_ENABLED(CONFIG_IPV6)
 932                 if (!*end)
 933                         return 1;
 934 #else
 935                 return -1;
 936 #endif
 937         }
 938         return -1;
 939 }
 940
 941 int netpoll_parse_options(struct netpoll *np, char *opt)
 942 {
 943         char *cur=opt, *delim;
 944         int ipv6;
 945
 946         if (*cur != '@') {
 947                 if ((delim = strchr(cur, '@')) == NULL)
 948                         goto parse_failed;
 949                 *delim = 0;
 950                 if (kstrtou16(cur, 10, &np->local_port))
 951                         goto parse_failed;
 952                 cur = delim;
 953         }
 954         cur++;
 955
 956         if (*cur != '/') {
 957                 if ((delim = strchr(cur, '/')) == NULL)
 958                         goto parse_failed;
 959                 *delim = 0;
 960                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 961                 if (ipv6 < 0)
 962                         goto parse_failed;
 963                 else
 964                         np->ipv6 = (bool)ipv6;
 965                 cur = delim;
 966         }
 967         cur++;
 968
 969         if (*cur != ',') {
 970                 /* parse out dev name */
 971                 if ((delim = strchr(cur, ',')) == NULL)
 972                         goto parse_failed;
 973                 *delim = 0;
 974                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 975                 cur = delim;
 976         }
 977         cur++;
 978
 979         if (*cur != '@') {
 980                 /* dst port */
 981                 if ((delim = strchr(cur, '@')) == NULL)
 982                         goto parse_failed;
 983                 *delim = 0;
 984                 if (*cur == ' ' || *cur == '\t')
 985                         np_info(np, "warning: whitespace is not allowed\n");
 986                 if (kstrtou16(cur, 10, &np->remote_port))
 987                         goto parse_failed;
 988                 cur = delim;
 989         }
 990         cur++;
 991
 992         /* dst ip */
 993         if ((delim = strchr(cur, '/')) == NULL)
 994                 goto parse_failed;
 995         *delim = 0;
 996         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 997         if (ipv6 < 0)
 998                 goto parse_failed;
 999         else if (np->ipv6 != (bool)ipv6)
1000                 goto parse_failed;
1001         else
1002                 np->ipv6 = (bool)ipv6;
1003         cur = delim + 1;
1004
1005         if (*cur != 0) {
1006                 /* MAC address */
1007                 if (!mac_pton(cur, np->remote_mac))
1008                         goto parse_failed;
1009         }
1010
1011         netpoll_print_options(np);
1012
1013         return 0;
1014
1015  parse_failed:
1016         np_info(np, "couldn't parse config at '%s'!\n", cur);
1017         return -1;
1018 }
1019 EXPORT_SYMBOL(netpoll_parse_options);
1020
1021 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
1022 {
1023         struct netpoll_info *npinfo;
1024         const struct net_device_ops *ops;
1025         unsigned long flags;
1026         int err;
1027
1028         np->dev = ndev;
1029         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
1030         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
1031
1032         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
1033             !ndev->netdev_ops->ndo_poll_controller) {
1034                 np_err(np, "%s doesn't support polling, aborting\n",
1035                        np->dev_name);
1036                 err = -ENOTSUPP;
1037                 goto out;
1038         }
1039
1040         if (!ndev->npinfo) {
1041                 npinfo = kmalloc(sizeof(*npinfo), gfp);
1042                 if (!npinfo) {
1043                         err = -ENOMEM;
1044                         goto out;
1045                 }
1046
1047                 npinfo->rx_flags = 0;
1048                 INIT_LIST_HEAD(&npinfo->rx_np);
1049
1050                 spin_lock_init(&npinfo->rx_lock);
1051                 sema_init(&npinfo->dev_lock, 1);
1052                 skb_queue_head_init(&npinfo->neigh_tx);
1053                 skb_queue_head_init(&npinfo->txq);
1054                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
1055
1056                 atomic_set(&npinfo->refcnt, 1);
1057
1058                 ops = np->dev->netdev_ops;
1059                 if (ops->ndo_netpoll_setup) {
1060                         err = ops->ndo_netpoll_setup(ndev, npinfo, gfp);
1061                         if (err)
1062                                 goto free_npinfo;
1063                 }
1064         } else {
1065                 npinfo = rtnl_dereference(ndev->npinfo);
1066                 atomic_inc(&npinfo->refcnt);
1067         }
1068
1069         npinfo->netpoll = np;
1070
1071         if (np->rx_hook) {
1072                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1073                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
1074                 list_add_tail(&np->rx, &npinfo->rx_np);
1075                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1076         }
1077
1078         /* last thing to do is link it to the net device structure */
1079         rcu_assign_pointer(ndev->npinfo, npinfo);
1080
1081         return 0;
1082
1083 free_npinfo:
1084         kfree(npinfo);
1085 out:
1086         return err;
1087 }
1088 EXPORT_SYMBOL_GPL(__netpoll_setup);
1089
1090 int netpoll_setup(struct netpoll *np)
1091 {
1092         struct net_device *ndev = NULL;
1093         struct in_device *in_dev;
1094         int err;
1095
1096         rtnl_lock();
1097         if (np->dev_name) {
1098                 struct net *net = current->nsproxy->net_ns;
1099                 ndev = __dev_get_by_name(net, np->dev_name);
1100         }
1101         if (!ndev) {
1102                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
1103                 err = -ENODEV;
1104                 goto unlock;
1105         }
1106         dev_hold(ndev);
1107
1108         if (netdev_master_upper_dev_get(ndev)) {
1109                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
1110                 err = -EBUSY;
1111                 goto put;
1112         }
1113
1114         if (!netif_running(ndev)) {
1115                 unsigned long atmost, atleast;
1116
1117                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
1118
1119                 err = dev_open(ndev);
1120
1121                 if (err) {
1122                         np_err(np, "failed to open %s\n", ndev->name);
1123                         goto put;
1124                 }
1125
1126                 rtnl_unlock();
1127                 atleast = jiffies + HZ/10;
1128                 atmost = jiffies + carrier_timeout * HZ;
1129                 while (!netif_carrier_ok(ndev)) {
1130                         if (time_after(jiffies, atmost)) {
1131                                 np_notice(np, "timeout waiting for carrier\n");
1132                                 break;
1133                         }
1134                         msleep(1);
1135                 }
1136
1137                 /* If carrier appears to come up instantly, we don't
1138                  * trust it and pause so that we don't pump all our
1139                  * queued console messages into the bitbucket.
1140                  */
1141
1142                 if (time_before(jiffies, atleast)) {
1143                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
1144                         msleep(4000);
1145                 }
1146                 rtnl_lock();
1147         }
1148
1149         if (!np->local_ip.ip) {
1150                 if (!np->ipv6) {
1151                         in_dev = __in_dev_get_rtnl(ndev);
1152
1153                         if (!in_dev || !in_dev->ifa_list) {
1154                                 np_err(np, "no IP address for %s, aborting\n",
1155                                        np->dev_name);
1156                                 err = -EDESTADDRREQ;
1157                                 goto put;
1158                         }
1159
1160                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
1161                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
1162                 } else {
1163 #if IS_ENABLED(CONFIG_IPV6)
1164                         struct inet6_dev *idev;
1165
1166                         err = -EDESTADDRREQ;
1167                         idev = __in6_dev_get(ndev);
1168                         if (idev) {
1169                                 struct inet6_ifaddr *ifp;
1170
1171                                 read_lock_bh(&idev->lock);
1172                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
1173                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
1174                                                 continue;
1175                                         np->local_ip.in6 = ifp->addr;
1176                                         err = 0;
1177                                         break;
1178                                 }
1179                                 read_unlock_bh(&idev->lock);
1180                         }
1181                         if (err) {
1182                                 np_err(np, "no IPv6 address for %s, aborting\n",
1183                                        np->dev_name);
1184                                 goto put;
1185                         } else
1186                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
1187 #else
1188                         np_err(np, "IPv6 is not supported %s, aborting\n",
1189                                np->dev_name);
1190                         err = -EINVAL;
1191                         goto put;
1192 #endif
1193                 }
1194         }
1195
1196         /* fill up the skb queue */
1197         refill_skbs();
1198
1199         err = __netpoll_setup(np, ndev, GFP_KERNEL);
1200         if (err)
1201                 goto put;
1202
1203         rtnl_unlock();
1204         return 0;
1205
1206 put:
1207         dev_put(ndev);
1208 unlock:
1209         rtnl_unlock();
1210         return err;
1211 }
1212 EXPORT_SYMBOL(netpoll_setup);
1213
1214 static int __init netpoll_init(void)
1215 {
1216         skb_queue_head_init(&skb_pool);
1217         return 0;
1218 }
1219 core_initcall(netpoll_init);
1220
1221 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
1222 {
1223         struct netpoll_info *npinfo =
1224                         container_of(rcu_head, struct netpoll_info, rcu);
1225
1226         skb_queue_purge(&npinfo->neigh_tx);
1227         skb_queue_purge(&npinfo->txq);
1228
1229         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
1230         cancel_delayed_work(&npinfo->tx_work);
1231
1232         /* clean after last, unfinished work */
1233         __skb_queue_purge(&npinfo->txq);
1234         /* now cancel it again */
1235         cancel_delayed_work(&npinfo->tx_work);
1236         kfree(npinfo);
1237 }
1238
1239 void __netpoll_cleanup(struct netpoll *np)
1240 {
1241         struct netpoll_info *npinfo;
1242         unsigned long flags;
1243
1244         /* rtnl_dereference would be preferable here but
1245          * rcu_cleanup_netpoll path can put us in here safely without
1246          * holding the rtnl, so plain rcu_dereference it is
1247          */
1248         npinfo = rtnl_dereference(np->dev->npinfo);
1249         if (!npinfo)
1250                 return;
1251
1252         if (!list_empty(&npinfo->rx_np)) {
1253                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1254                 list_del(&np->rx);
1255                 if (list_empty(&npinfo->rx_np))
1256                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
1257                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1258         }
1259
1260         synchronize_srcu(&netpoll_srcu);
1261
1262         if (atomic_dec_and_test(&npinfo->refcnt)) {
1263                 const struct net_device_ops *ops;
1264
1265                 ops = np->dev->netdev_ops;
1266                 if (ops->ndo_netpoll_cleanup)
1267                         ops->ndo_netpoll_cleanup(np->dev);
1268
1269                 rcu_assign_pointer(np->dev->npinfo, NULL);
1270                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
1271         }
1272 }
1273 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
1274
1275 static void netpoll_async_cleanup(struct work_struct *work)
1276 {
1277         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
1278
1279         rtnl_lock();
1280         __netpoll_cleanup(np);
1281         rtnl_unlock();
1282         kfree(np);
1283 }
1284
1285 void __netpoll_free_async(struct netpoll *np)
1286 {
1287         schedule_work(&np->cleanup_work);
1288 }
1289 EXPORT_SYMBOL_GPL(__netpoll_free_async);
1290
1291 void netpoll_cleanup(struct netpoll *np)
1292 {
1293         if (!np->dev)
1294                 return;
1295
1296         rtnl_lock();
1297         __netpoll_cleanup(np);
1298         rtnl_unlock();
1299
1300         dev_put(np->dev);
1301         np->dev = NULL;
1302 }
1303 EXPORT_SYMBOL(netpoll_cleanup);
1304
1305 int netpoll_trap(void)
1306 {
1307         return atomic_read(&trapped);
1308 }
1309 EXPORT_SYMBOL(netpoll_trap);
1310
1311 void netpoll_set_trap(int trap)
1312 {
1313         if (trap)
1314                 atomic_inc(&trapped);
1315         else
1316                 atomic_dec(&trapped);
1317 }
1318 EXPORT_SYMBOL(netpoll_set_trap);