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/netdevice.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/string.h>
  18 #include <linux/if_arp.h>
  19 #include <linux/inetdevice.h>
  20 #include <linux/inet.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/netpoll.h>
  23 #include <linux/sched.h>
  24 #include <linux/delay.h>
  25 #include <linux/rcupdate.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/slab.h>
  28 #include <linux/export.h>
  29 #include <linux/if_vlan.h>
  30 #include <net/tcp.h>
  31 #include <net/udp.h>
  32 #include <net/addrconf.h>
  33 #include <net/ndisc.h>
  34 #include <net/ip6_checksum.h>
  35 #include <asm/unaligned.h>
  36 #include <trace/events/napi.h>
  37
  38 /*
  39  * We maintain a small pool of fully-sized skbs, to make sure the
  40  * message gets out even in extreme OOM situations.
  41  */
  42
  43 #define MAX_UDP_CHUNK 1460
  44 #define MAX_SKBS 32
  45
  46 static struct sk_buff_head skb_pool;
  47
  48 static atomic_t trapped;
  49
  50 DEFINE_STATIC_SRCU(netpoll_srcu);
  51
  52 #define USEC_PER_POLL   50
  53 #define NETPOLL_RX_ENABLED  1
  54 #define NETPOLL_RX_DROP     2
  55
  56 #define MAX_SKB_SIZE                                                    \
  57         (sizeof(struct ethhdr) +                                        \
  58          sizeof(struct iphdr) +                                         \
  59          sizeof(struct udphdr) +                                        \
  60          MAX_UDP_CHUNK)
  61
  62 static void zap_completion_queue(void);
  63 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo);
  64 static void netpoll_async_cleanup(struct work_struct *work);
  65
  66 static unsigned int carrier_timeout = 4;
  67 module_param(carrier_timeout, uint, 0644);
  68
  69 #define np_info(np, fmt, ...)                           \
  70         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  71 #define np_err(np, fmt, ...)                            \
  72         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  73 #define np_notice(np, fmt, ...)                         \
  74         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  75
  76 static void queue_process(struct work_struct *work)
  77 {
  78         struct netpoll_info *npinfo =
  79                 container_of(work, struct netpoll_info, tx_work.work);
  80         struct sk_buff *skb;
  81         unsigned long flags;
  82
  83         while ((skb = skb_dequeue(&npinfo->txq))) {
  84                 struct net_device *dev = skb->dev;
  85                 const struct net_device_ops *ops = dev->netdev_ops;
  86                 struct netdev_queue *txq;
  87
  88                 if (!netif_device_present(dev) || !netif_running(dev)) {
  89                         __kfree_skb(skb);
  90                         continue;
  91                 }
  92
  93                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  94
  95                 local_irq_save(flags);
  96                 __netif_tx_lock(txq, smp_processor_id());
  97                 if (netif_xmit_frozen_or_stopped(txq) ||
  98                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  99                         skb_queue_head(&npinfo->txq, skb);
 100                         __netif_tx_unlock(txq);
 101                         local_irq_restore(flags);
 102
 103                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 104                         return;
 105                 }
 106                 __netif_tx_unlock(txq);
 107                 local_irq_restore(flags);
 108         }
 109 }
 110
 111 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 112                             unsigned short ulen, __be32 saddr, __be32 daddr)
 113 {
 114         __wsum psum;
 115
 116         if (uh->check == 0 || skb_csum_unnecessary(skb))
 117                 return 0;
 118
 119         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 120
 121         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 122             !csum_fold(csum_add(psum, skb->csum)))
 123                 return 0;
 124
 125         skb->csum = psum;
 126
 127         return __skb_checksum_complete(skb);
 128 }
 129
 130 /*
 131  * Check whether delayed processing was scheduled for our NIC. If so,
 132  * we attempt to grab the poll lock and use ->poll() to pump the card.
 133  * If this fails, either we've recursed in ->poll() or it's already
 134  * running on another CPU.
 135  *
 136  * Note: we don't mask interrupts with this lock because we're using
 137  * trylock here and interrupts are already disabled in the softirq
 138  * case. Further, we test the poll_owner to avoid recursion on UP
 139  * systems where the lock doesn't exist.
 140  *
 141  * In cases where there is bi-directional communications, reading only
 142  * one message at a time can lead to packets being dropped by the
 143  * network adapter, forcing superfluous retries and possibly timeouts.
 144  * Thus, we set our budget to greater than 1.
 145  */
 146 static int poll_one_napi(struct netpoll_info *npinfo,
 147                          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         npinfo->rx_flags |= NETPOLL_RX_DROP;
 159         atomic_inc(&trapped);
 160         set_bit(NAPI_STATE_NPSVC, &napi->state);
 161
 162         work = napi->poll(napi, budget);
 163         trace_napi_poll(napi);
 164
 165         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 166         atomic_dec(&trapped);
 167         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 168
 169         return budget - work;
 170 }
 171
 172 static void poll_napi(struct net_device *dev)
 173 {
 174         struct napi_struct *napi;
 175         int budget = 16;
 176
 177         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 178                 if (napi->poll_owner != smp_processor_id() &&
 179                     spin_trylock(&napi->poll_lock)) {
 180                         budget = poll_one_napi(rcu_dereference_bh(dev->npinfo),
 181                                                napi, budget);
 182                         spin_unlock(&napi->poll_lock);
 183
 184                         if (!budget)
 185                                 break;
 186                 }
 187         }
 188 }
 189
 190 static void service_neigh_queue(struct netpoll_info *npi)
 191 {
 192         if (npi) {
 193                 struct sk_buff *skb;
 194
 195                 while ((skb = skb_dequeue(&npi->neigh_tx)))
 196                         netpoll_neigh_reply(skb, npi);
 197         }
 198 }
 199
 200 static void netpoll_poll_dev(struct net_device *dev)
 201 {
 202         const struct net_device_ops *ops;
 203         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 204
 205         /* Don't do any rx activity if the dev_lock mutex is held
 206          * the dev_open/close paths use this to block netpoll activity
 207          * while changing device state
 208          */
 209         if (down_trylock(&ni->dev_lock))
 210                 return;
 211
 212         if (!netif_running(dev)) {
 213                 up(&ni->dev_lock);
 214                 return;
 215         }
 216
 217         ops = dev->netdev_ops;
 218         if (!ops->ndo_poll_controller) {
 219                 up(&ni->dev_lock);
 220                 return;
 221         }
 222
 223         /* Process pending work on NIC */
 224         ops->ndo_poll_controller(dev);
 225
 226         poll_napi(dev);
 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 int 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         return 0;
 261 }
 262 EXPORT_SYMBOL(netpoll_rx_disable);
 263
 264 void netpoll_rx_enable(struct net_device *dev)
 265 {
 266         struct netpoll_info *ni;
 267         rcu_read_lock();
 268         ni = rcu_dereference(dev->npinfo);
 269         if (ni)
 270                 up(&ni->dev_lock);
 271         rcu_read_unlock();
 272 }
 273 EXPORT_SYMBOL(netpoll_rx_enable);
 274
 275 static void refill_skbs(void)
 276 {
 277         struct sk_buff *skb;
 278         unsigned long flags;
 279
 280         spin_lock_irqsave(&skb_pool.lock, flags);
 281         while (skb_pool.qlen < MAX_SKBS) {
 282                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 283                 if (!skb)
 284                         break;
 285
 286                 __skb_queue_tail(&skb_pool, skb);
 287         }
 288         spin_unlock_irqrestore(&skb_pool.lock, flags);
 289 }
 290
 291 static void zap_completion_queue(void)
 292 {
 293         unsigned long flags;
 294         struct softnet_data *sd = &get_cpu_var(softnet_data);
 295
 296         if (sd->completion_queue) {
 297                 struct sk_buff *clist;
 298
 299                 local_irq_save(flags);
 300                 clist = sd->completion_queue;
 301                 sd->completion_queue = NULL;
 302                 local_irq_restore(flags);
 303
 304                 while (clist != NULL) {
 305                         struct sk_buff *skb = clist;
 306                         clist = clist->next;
 307                         if (skb->destructor) {
 308                                 atomic_inc(&skb->users);
 309                                 dev_kfree_skb_any(skb); /* put this one back */
 310                         } else {
 311                                 __kfree_skb(skb);
 312                         }
 313                 }
 314         }
 315
 316         put_cpu_var(softnet_data);
 317 }
 318
 319 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 320 {
 321         int count = 0;
 322         struct sk_buff *skb;
 323
 324         zap_completion_queue();
 325         refill_skbs();
 326 repeat:
 327
 328         skb = alloc_skb(len, GFP_ATOMIC);
 329         if (!skb)
 330                 skb = skb_dequeue(&skb_pool);
 331
 332         if (!skb) {
 333                 if (++count < 10) {
 334                         netpoll_poll_dev(np->dev);
 335                         goto repeat;
 336                 }
 337                 return NULL;
 338         }
 339
 340         atomic_set(&skb->users, 1);
 341         skb_reserve(skb, reserve);
 342         return skb;
 343 }
 344
 345 static int netpoll_owner_active(struct net_device *dev)
 346 {
 347         struct napi_struct *napi;
 348
 349         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 350                 if (napi->poll_owner == smp_processor_id())
 351                         return 1;
 352         }
 353         return 0;
 354 }
 355
 356 /* call with IRQ disabled */
 357 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 358                              struct net_device *dev)
 359 {
 360         int status = NETDEV_TX_BUSY;
 361         unsigned long tries;
 362         const struct net_device_ops *ops = dev->netdev_ops;
 363         /* It is up to the caller to keep npinfo alive. */
 364         struct netpoll_info *npinfo;
 365
 366         WARN_ON_ONCE(!irqs_disabled());
 367
 368         npinfo = rcu_dereference_bh(np->dev->npinfo);
 369         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 370                 __kfree_skb(skb);
 371                 return;
 372         }
 373
 374         /* don't get messages out of order, and no recursion */
 375         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 376                 struct netdev_queue *txq;
 377
 378                 txq = netdev_pick_tx(dev, skb);
 379
 380                 /* try until next clock tick */
 381                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 382                      tries > 0; --tries) {
 383                         if (__netif_tx_trylock(txq)) {
 384                                 if (!netif_xmit_stopped(txq)) {
 385                                         if (vlan_tx_tag_present(skb) &&
 386                                             !vlan_hw_offload_capable(netif_skb_features(skb),
 387                                                                      skb->vlan_proto)) {
 388                                                 skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
 389                                                 if (unlikely(!skb))
 390                                                         break;
 391                                                 skb->vlan_tci = 0;
 392                                         }
 393
 394                                         status = ops->ndo_start_xmit(skb, dev);
 395                                         if (status == NETDEV_TX_OK)
 396                                                 txq_trans_update(txq);
 397                                 }
 398                                 __netif_tx_unlock(txq);
 399
 400                                 if (status == NETDEV_TX_OK)
 401                                         break;
 402
 403                         }
 404
 405                         /* tickle device maybe there is some cleanup */
 406                         netpoll_poll_dev(np->dev);
 407
 408                         udelay(USEC_PER_POLL);
 409                 }
 410
 411                 WARN_ONCE(!irqs_disabled(),
 412                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 413                         dev->name, ops->ndo_start_xmit);
 414
 415         }
 416
 417         if (status != NETDEV_TX_OK) {
 418                 skb_queue_tail(&npinfo->txq, skb);
 419                 schedule_delayed_work(&npinfo->tx_work,0);
 420         }
 421 }
 422 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 423
 424 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 425 {
 426         int total_len, ip_len, udp_len;
 427         struct sk_buff *skb;
 428         struct udphdr *udph;
 429         struct iphdr *iph;
 430         struct ethhdr *eth;
 431         static atomic_t ip_ident;
 432         struct ipv6hdr *ip6h;
 433
 434         udp_len = len + sizeof(*udph);
 435         if (np->ipv6)
 436                 ip_len = udp_len + sizeof(*ip6h);
 437         else
 438                 ip_len = udp_len + sizeof(*iph);
 439
 440         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 441
 442         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 443                        total_len - len);
 444         if (!skb)
 445                 return;
 446
 447         skb_copy_to_linear_data(skb, msg, len);
 448         skb_put(skb, len);
 449
 450         skb_push(skb, sizeof(*udph));
 451         skb_reset_transport_header(skb);
 452         udph = udp_hdr(skb);
 453         udph->source = htons(np->local_port);
 454         udph->dest = htons(np->remote_port);
 455         udph->len = htons(udp_len);
 456
 457         if (np->ipv6) {
 458                 udph->check = 0;
 459                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 460                                               &np->remote_ip.in6,
 461                                               udp_len, IPPROTO_UDP,
 462                                               csum_partial(udph, udp_len, 0));
 463                 if (udph->check == 0)
 464                         udph->check = CSUM_MANGLED_0;
 465
 466                 skb_push(skb, sizeof(*ip6h));
 467                 skb_reset_network_header(skb);
 468                 ip6h = ipv6_hdr(skb);
 469
 470                 /* ip6h->version = 6; ip6h->priority = 0; */
 471                 put_unaligned(0x60, (unsigned char *)ip6h);
 472                 ip6h->flow_lbl[0] = 0;
 473                 ip6h->flow_lbl[1] = 0;
 474                 ip6h->flow_lbl[2] = 0;
 475
 476                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 477                 ip6h->nexthdr = IPPROTO_UDP;
 478                 ip6h->hop_limit = 32;
 479                 ip6h->saddr = np->local_ip.in6;
 480                 ip6h->daddr = np->remote_ip.in6;
 481
 482                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 483                 skb_reset_mac_header(skb);
 484                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 485         } else {
 486                 udph->check = 0;
 487                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 488                                                 np->remote_ip.ip,
 489                                                 udp_len, IPPROTO_UDP,
 490                                                 csum_partial(udph, udp_len, 0));
 491                 if (udph->check == 0)
 492                         udph->check = CSUM_MANGLED_0;
 493
 494                 skb_push(skb, sizeof(*iph));
 495                 skb_reset_network_header(skb);
 496                 iph = ip_hdr(skb);
 497
 498                 /* iph->version = 4; iph->ihl = 5; */
 499                 put_unaligned(0x45, (unsigned char *)iph);
 500                 iph->tos      = 0;
 501                 put_unaligned(htons(ip_len), &(iph->tot_len));
 502                 iph->id       = htons(atomic_inc_return(&ip_ident));
 503                 iph->frag_off = 0;
 504                 iph->ttl      = 64;
 505                 iph->protocol = IPPROTO_UDP;
 506                 iph->check    = 0;
 507                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 508                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 509                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 510
 511                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 512                 skb_reset_mac_header(skb);
 513                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 514         }
 515
 516         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 517         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 518
 519         skb->dev = np->dev;
 520
 521         netpoll_send_skb(np, skb);
 522 }
 523 EXPORT_SYMBOL(netpoll_send_udp);
 524
 525 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo)
 526 {
 527         int size, type = ARPOP_REPLY;
 528         __be32 sip, tip;
 529         unsigned char *sha;
 530         struct sk_buff *send_skb;
 531         struct netpoll *np, *tmp;
 532         unsigned long flags;
 533         int hlen, tlen;
 534         int hits = 0, proto;
 535
 536         if (list_empty(&npinfo->rx_np))
 537                 return;
 538
 539         /* Before checking the packet, we do some early
 540            inspection whether this is interesting at all */
 541         spin_lock_irqsave(&npinfo->rx_lock, flags);
 542         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 543                 if (np->dev == skb->dev)
 544                         hits++;
 545         }
 546         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 547
 548         /* No netpoll struct is using this dev */
 549         if (!hits)
 550                 return;
 551
 552         proto = ntohs(eth_hdr(skb)->h_proto);
 553         if (proto == ETH_P_IP) {
 554                 struct arphdr *arp;
 555                 unsigned char *arp_ptr;
 556                 /* No arp on this interface */
 557                 if (skb->dev->flags & IFF_NOARP)
 558                         return;
 559
 560                 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 561                         return;
 562
 563                 skb_reset_network_header(skb);
 564                 skb_reset_transport_header(skb);
 565                 arp = arp_hdr(skb);
 566
 567                 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 568                      arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 569                     arp->ar_pro != htons(ETH_P_IP) ||
 570                     arp->ar_op != htons(ARPOP_REQUEST))
 571                         return;
 572
 573                 arp_ptr = (unsigned char *)(arp+1);
 574                 /* save the location of the src hw addr */
 575                 sha = arp_ptr;
 576                 arp_ptr += skb->dev->addr_len;
 577                 memcpy(&sip, arp_ptr, 4);
 578                 arp_ptr += 4;
 579                 /* If we actually cared about dst hw addr,
 580                    it would get copied here */
 581                 arp_ptr += skb->dev->addr_len;
 582                 memcpy(&tip, arp_ptr, 4);
 583
 584                 /* Should we ignore arp? */
 585                 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 586                         return;
 587
 588                 size = arp_hdr_len(skb->dev);
 589
 590                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 591                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 592                         if (tip != np->local_ip.ip)
 593                                 continue;
 594
 595                         hlen = LL_RESERVED_SPACE(np->dev);
 596                         tlen = np->dev->needed_tailroom;
 597                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 598                         if (!send_skb)
 599                                 continue;
 600
 601                         skb_reset_network_header(send_skb);
 602                         arp = (struct arphdr *) skb_put(send_skb, size);
 603                         send_skb->dev = skb->dev;
 604                         send_skb->protocol = htons(ETH_P_ARP);
 605
 606                         /* Fill the device header for the ARP frame */
 607                         if (dev_hard_header(send_skb, skb->dev, ETH_P_ARP,
 608                                             sha, np->dev->dev_addr,
 609                                             send_skb->len) < 0) {
 610                                 kfree_skb(send_skb);
 611                                 continue;
 612                         }
 613
 614                         /*
 615                          * Fill out the arp protocol part.
 616                          *
 617                          * we only support ethernet device type,
 618                          * which (according to RFC 1390) should
 619                          * always equal 1 (Ethernet).
 620                          */
 621
 622                         arp->ar_hrd = htons(np->dev->type);
 623                         arp->ar_pro = htons(ETH_P_IP);
 624                         arp->ar_hln = np->dev->addr_len;
 625                         arp->ar_pln = 4;
 626                         arp->ar_op = htons(type);
 627
 628                         arp_ptr = (unsigned char *)(arp + 1);
 629                         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 630                         arp_ptr += np->dev->addr_len;
 631                         memcpy(arp_ptr, &tip, 4);
 632                         arp_ptr += 4;
 633                         memcpy(arp_ptr, sha, np->dev->addr_len);
 634                         arp_ptr += np->dev->addr_len;
 635                         memcpy(arp_ptr, &sip, 4);
 636
 637                         netpoll_send_skb(np, send_skb);
 638
 639                         /* If there are several rx_hooks for the same address,
 640                            we're fine by sending a single reply */
 641                         break;
 642                 }
 643                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 644         } else if( proto == ETH_P_IPV6) {
 645 #if IS_ENABLED(CONFIG_IPV6)
 646                 struct nd_msg *msg;
 647                 u8 *lladdr = NULL;
 648                 struct ipv6hdr *hdr;
 649                 struct icmp6hdr *icmp6h;
 650                 const struct in6_addr *saddr;
 651                 const struct in6_addr *daddr;
 652                 struct inet6_dev *in6_dev = NULL;
 653                 struct in6_addr *target;
 654
 655                 in6_dev = in6_dev_get(skb->dev);
 656                 if (!in6_dev || !in6_dev->cnf.accept_ra)
 657                         return;
 658
 659                 if (!pskb_may_pull(skb, skb->len))
 660                         return;
 661
 662                 msg = (struct nd_msg *)skb_transport_header(skb);
 663
 664                 __skb_push(skb, skb->data - skb_transport_header(skb));
 665
 666                 if (ipv6_hdr(skb)->hop_limit != 255)
 667                         return;
 668                 if (msg->icmph.icmp6_code != 0)
 669                         return;
 670                 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 671                         return;
 672
 673                 saddr = &ipv6_hdr(skb)->saddr;
 674                 daddr = &ipv6_hdr(skb)->daddr;
 675
 676                 size = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
 677
 678                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 679                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 680                         if (!ipv6_addr_equal(daddr, &np->local_ip.in6))
 681                                 continue;
 682
 683                         hlen = LL_RESERVED_SPACE(np->dev);
 684                         tlen = np->dev->needed_tailroom;
 685                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 686                         if (!send_skb)
 687                                 continue;
 688
 689                         send_skb->protocol = htons(ETH_P_IPV6);
 690                         send_skb->dev = skb->dev;
 691
 692                         skb_reset_network_header(send_skb);
 693                         skb_put(send_skb, sizeof(struct ipv6hdr));
 694                         hdr = ipv6_hdr(send_skb);
 695
 696                         *(__be32*)hdr = htonl(0x60000000);
 697
 698                         hdr->payload_len = htons(size);
 699                         hdr->nexthdr = IPPROTO_ICMPV6;
 700                         hdr->hop_limit = 255;
 701                         hdr->saddr = *saddr;
 702                         hdr->daddr = *daddr;
 703
 704                         send_skb->transport_header = send_skb->tail;
 705                         skb_put(send_skb, size);
 706
 707                         icmp6h = (struct icmp6hdr *)skb_transport_header(skb);
 708                         icmp6h->icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
 709                         icmp6h->icmp6_router = 0;
 710                         icmp6h->icmp6_solicited = 1;
 711                         target = (struct in6_addr *)(skb_transport_header(send_skb) + sizeof(struct icmp6hdr));
 712                         *target = msg->target;
 713                         icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, size,
 714                                                               IPPROTO_ICMPV6,
 715                                                               csum_partial(icmp6h,
 716                                                                            size, 0));
 717
 718                         if (dev_hard_header(send_skb, skb->dev, ETH_P_IPV6,
 719                                             lladdr, np->dev->dev_addr,
 720                                             send_skb->len) < 0) {
 721                                 kfree_skb(send_skb);
 722                                 continue;
 723                         }
 724
 725                         netpoll_send_skb(np, send_skb);
 726
 727                         /* If there are several rx_hooks for the same address,
 728                            we're fine by sending a single reply */
 729                         break;
 730                 }
 731                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 732 #endif
 733         }
 734 }
 735
 736 static bool pkt_is_ns(struct sk_buff *skb)
 737 {
 738         struct nd_msg *msg;
 739         struct ipv6hdr *hdr;
 740
 741         if (skb->protocol != htons(ETH_P_ARP))
 742                 return false;
 743         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct nd_msg)))
 744                 return false;
 745
 746         msg = (struct nd_msg *)skb_transport_header(skb);
 747         __skb_push(skb, skb->data - skb_transport_header(skb));
 748         hdr = ipv6_hdr(skb);
 749
 750         if (hdr->nexthdr != IPPROTO_ICMPV6)
 751                 return false;
 752         if (hdr->hop_limit != 255)
 753                 return false;
 754         if (msg->icmph.icmp6_code != 0)
 755                 return false;
 756         if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 757                 return false;
 758
 759         return true;
 760 }
 761
 762 int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo)
 763 {
 764         int proto, len, ulen;
 765         int hits = 0;
 766         const struct iphdr *iph;
 767         struct udphdr *uh;
 768         struct netpoll *np, *tmp;
 769
 770         if (list_empty(&npinfo->rx_np))
 771                 goto out;
 772
 773         if (skb->dev->type != ARPHRD_ETHER)
 774                 goto out;
 775
 776         /* check if netpoll clients need ARP */
 777         if (skb->protocol == htons(ETH_P_ARP) && atomic_read(&trapped)) {
 778                 skb_queue_tail(&npinfo->neigh_tx, skb);
 779                 return 1;
 780         } else if (pkt_is_ns(skb) && atomic_read(&trapped)) {
 781                 skb_queue_tail(&npinfo->neigh_tx, skb);
 782                 return 1;
 783         }
 784
 785         if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
 786                 skb = vlan_untag(skb);
 787                 if (unlikely(!skb))
 788                         goto out;
 789         }
 790
 791         proto = ntohs(eth_hdr(skb)->h_proto);
 792         if (proto != ETH_P_IP && proto != ETH_P_IPV6)
 793                 goto out;
 794         if (skb->pkt_type == PACKET_OTHERHOST)
 795                 goto out;
 796         if (skb_shared(skb))
 797                 goto out;
 798
 799         if (proto == ETH_P_IP) {
 800                 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 801                         goto out;
 802                 iph = (struct iphdr *)skb->data;
 803                 if (iph->ihl < 5 || iph->version != 4)
 804                         goto out;
 805                 if (!pskb_may_pull(skb, iph->ihl*4))
 806                         goto out;
 807                 iph = (struct iphdr *)skb->data;
 808                 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 809                         goto out;
 810
 811                 len = ntohs(iph->tot_len);
 812                 if (skb->len < len || len < iph->ihl*4)
 813                         goto out;
 814
 815                 /*
 816                  * Our transport medium may have padded the buffer out.
 817                  * Now We trim to the true length of the frame.
 818                  */
 819                 if (pskb_trim_rcsum(skb, len))
 820                         goto out;
 821
 822                 iph = (struct iphdr *)skb->data;
 823                 if (iph->protocol != IPPROTO_UDP)
 824                         goto out;
 825
 826                 len -= iph->ihl*4;
 827                 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 828                 ulen = ntohs(uh->len);
 829
 830                 if (ulen != len)
 831                         goto out;
 832                 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 833                         goto out;
 834                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 835                         if (np->local_ip.ip && np->local_ip.ip != iph->daddr)
 836                                 continue;
 837                         if (np->remote_ip.ip && np->remote_ip.ip != iph->saddr)
 838                                 continue;
 839                         if (np->local_port && np->local_port != ntohs(uh->dest))
 840                                 continue;
 841
 842                         np->rx_hook(np, ntohs(uh->source),
 843                                        (char *)(uh+1),
 844                                        ulen - sizeof(struct udphdr));
 845                         hits++;
 846                 }
 847         } else {
 848 #if IS_ENABLED(CONFIG_IPV6)
 849                 const struct ipv6hdr *ip6h;
 850
 851                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 852                         goto out;
 853                 ip6h = (struct ipv6hdr *)skb->data;
 854                 if (ip6h->version != 6)
 855                         goto out;
 856                 len = ntohs(ip6h->payload_len);
 857                 if (!len)
 858                         goto out;
 859                 if (len + sizeof(struct ipv6hdr) > skb->len)
 860                         goto out;
 861                 if (pskb_trim_rcsum(skb, len + sizeof(struct ipv6hdr)))
 862                         goto out;
 863                 ip6h = ipv6_hdr(skb);
 864                 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 865                         goto out;
 866                 uh = udp_hdr(skb);
 867                 ulen = ntohs(uh->len);
 868                 if (ulen != skb->len)
 869                         goto out;
 870                 if (udp6_csum_init(skb, uh, IPPROTO_UDP))
 871                         goto out;
 872                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 873                         if (!ipv6_addr_equal(&np->local_ip.in6, &ip6h->daddr))
 874                                 continue;
 875                         if (!ipv6_addr_equal(&np->remote_ip.in6, &ip6h->saddr))
 876                                 continue;
 877                         if (np->local_port && np->local_port != ntohs(uh->dest))
 878                                 continue;
 879
 880                         np->rx_hook(np, ntohs(uh->source),
 881                                        (char *)(uh+1),
 882                                        ulen - sizeof(struct udphdr));
 883                         hits++;
 884                 }
 885 #endif
 886         }
 887
 888         if (!hits)
 889                 goto out;
 890
 891         kfree_skb(skb);
 892         return 1;
 893
 894 out:
 895         if (atomic_read(&trapped)) {
 896                 kfree_skb(skb);
 897                 return 1;
 898         }
 899
 900         return 0;
 901 }
 902
 903 void netpoll_print_options(struct netpoll *np)
 904 {
 905         np_info(np, "local port %d\n", np->local_port);
 906         if (np->ipv6)
 907                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 908         else
 909                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 910         np_info(np, "interface '%s'\n", np->dev_name);
 911         np_info(np, "remote port %d\n", np->remote_port);
 912         if (np->ipv6)
 913                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 914         else
 915                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 916         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 917 }
 918 EXPORT_SYMBOL(netpoll_print_options);
 919
 920 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 921 {
 922         const char *end;
 923
 924         if (!strchr(str, ':') &&
 925             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 926                 if (!*end)
 927                         return 0;
 928         }
 929         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 930 #if IS_ENABLED(CONFIG_IPV6)
 931                 if (!*end)
 932                         return 1;
 933 #else
 934                 return -1;
 935 #endif
 936         }
 937         return -1;
 938 }
 939
 940 int netpoll_parse_options(struct netpoll *np, char *opt)
 941 {
 942         char *cur=opt, *delim;
 943         int ipv6;
 944
 945         if (*cur != '@') {
 946                 if ((delim = strchr(cur, '@')) == NULL)
 947                         goto parse_failed;
 948                 *delim = 0;
 949                 if (kstrtou16(cur, 10, &np->local_port))
 950                         goto parse_failed;
 951                 cur = delim;
 952         }
 953         cur++;
 954
 955         if (*cur != '/') {
 956                 if ((delim = strchr(cur, '/')) == NULL)
 957                         goto parse_failed;
 958                 *delim = 0;
 959                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 960                 if (ipv6 < 0)
 961                         goto parse_failed;
 962                 else
 963                         np->ipv6 = (bool)ipv6;
 964                 cur = delim;
 965         }
 966         cur++;
 967
 968         if (*cur != ',') {
 969                 /* parse out dev name */
 970                 if ((delim = strchr(cur, ',')) == NULL)
 971                         goto parse_failed;
 972                 *delim = 0;
 973                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 974                 cur = delim;
 975         }
 976         cur++;
 977
 978         if (*cur != '@') {
 979                 /* dst port */
 980                 if ((delim = strchr(cur, '@')) == NULL)
 981                         goto parse_failed;
 982                 *delim = 0;
 983                 if (*cur == ' ' || *cur == '\t')
 984                         np_info(np, "warning: whitespace is not allowed\n");
 985                 if (kstrtou16(cur, 10, &np->remote_port))
 986                         goto parse_failed;
 987                 cur = delim;
 988         }
 989         cur++;
 990
 991         /* dst ip */
 992         if ((delim = strchr(cur, '/')) == NULL)
 993                 goto parse_failed;
 994         *delim = 0;
 995         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 996         if (ipv6 < 0)
 997                 goto parse_failed;
 998         else if (np->ipv6 != (bool)ipv6)
 999                 goto parse_failed;
1000         else
1001                 np->ipv6 = (bool)ipv6;
1002         cur = delim + 1;
1003
1004         if (*cur != 0) {
1005                 /* MAC address */
1006                 if (!mac_pton(cur, np->remote_mac))
1007                         goto parse_failed;
1008         }
1009
1010         netpoll_print_options(np);
1011
1012         return 0;
1013
1014  parse_failed:
1015         np_info(np, "couldn't parse config at '%s'!\n", cur);
1016         return -1;
1017 }
1018 EXPORT_SYMBOL(netpoll_parse_options);
1019
1020 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
1021 {
1022         struct netpoll_info *npinfo;
1023         const struct net_device_ops *ops;
1024         unsigned long flags;
1025         int err;
1026
1027         np->dev = ndev;
1028         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
1029         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
1030
1031         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
1032             !ndev->netdev_ops->ndo_poll_controller) {
1033                 np_err(np, "%s doesn't support polling, aborting\n",
1034                        np->dev_name);
1035                 err = -ENOTSUPP;
1036                 goto out;
1037         }
1038
1039         if (!ndev->npinfo) {
1040                 npinfo = kmalloc(sizeof(*npinfo), gfp);
1041                 if (!npinfo) {
1042                         err = -ENOMEM;
1043                         goto out;
1044                 }
1045
1046                 npinfo->rx_flags = 0;
1047                 INIT_LIST_HEAD(&npinfo->rx_np);
1048
1049                 spin_lock_init(&npinfo->rx_lock);
1050                 sema_init(&npinfo->dev_lock, 1);
1051                 skb_queue_head_init(&npinfo->neigh_tx);
1052                 skb_queue_head_init(&npinfo->txq);
1053                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
1054
1055                 atomic_set(&npinfo->refcnt, 1);
1056
1057                 ops = np->dev->netdev_ops;
1058                 if (ops->ndo_netpoll_setup) {
1059                         err = ops->ndo_netpoll_setup(ndev, npinfo, gfp);
1060                         if (err)
1061                                 goto free_npinfo;
1062                 }
1063         } else {
1064                 npinfo = rtnl_dereference(ndev->npinfo);
1065                 atomic_inc(&npinfo->refcnt);
1066         }
1067
1068         npinfo->netpoll = np;
1069
1070         if (np->rx_hook) {
1071                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1072                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
1073                 list_add_tail(&np->rx, &npinfo->rx_np);
1074                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1075         }
1076
1077         /* last thing to do is link it to the net device structure */
1078         rcu_assign_pointer(ndev->npinfo, npinfo);
1079
1080         return 0;
1081
1082 free_npinfo:
1083         kfree(npinfo);
1084 out:
1085         return err;
1086 }
1087 EXPORT_SYMBOL_GPL(__netpoll_setup);
1088
1089 int netpoll_setup(struct netpoll *np)
1090 {
1091         struct net_device *ndev = NULL;
1092         struct in_device *in_dev;
1093         int err;
1094
1095         rtnl_lock();
1096         if (np->dev_name) {
1097                 struct net *net = current->nsproxy->net_ns;
1098                 ndev = __dev_get_by_name(net, np->dev_name);
1099         }
1100         if (!ndev) {
1101                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
1102                 err = -ENODEV;
1103                 goto unlock;
1104         }
1105         dev_hold(ndev);
1106
1107         if (netdev_master_upper_dev_get(ndev)) {
1108                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
1109                 err = -EBUSY;
1110                 goto put;
1111         }
1112
1113         if (!netif_running(ndev)) {
1114                 unsigned long atmost, atleast;
1115
1116                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
1117
1118                 err = dev_open(ndev);
1119
1120                 if (err) {
1121                         np_err(np, "failed to open %s\n", ndev->name);
1122                         goto put;
1123                 }
1124
1125                 rtnl_unlock();
1126                 atleast = jiffies + HZ/10;
1127                 atmost = jiffies + carrier_timeout * HZ;
1128                 while (!netif_carrier_ok(ndev)) {
1129                         if (time_after(jiffies, atmost)) {
1130                                 np_notice(np, "timeout waiting for carrier\n");
1131                                 break;
1132                         }
1133                         msleep(1);
1134                 }
1135
1136                 /* If carrier appears to come up instantly, we don't
1137                  * trust it and pause so that we don't pump all our
1138                  * queued console messages into the bitbucket.
1139                  */
1140
1141                 if (time_before(jiffies, atleast)) {
1142                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
1143                         msleep(4000);
1144                 }
1145                 rtnl_lock();
1146         }
1147
1148         if (!np->local_ip.ip) {
1149                 if (!np->ipv6) {
1150                         in_dev = __in_dev_get_rtnl(ndev);
1151
1152                         if (!in_dev || !in_dev->ifa_list) {
1153                                 np_err(np, "no IP address for %s, aborting\n",
1154                                        np->dev_name);
1155                                 err = -EDESTADDRREQ;
1156                                 goto put;
1157                         }
1158
1159                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
1160                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
1161                 } else {
1162 #if IS_ENABLED(CONFIG_IPV6)
1163                         struct inet6_dev *idev;
1164
1165                         err = -EDESTADDRREQ;
1166                         idev = __in6_dev_get(ndev);
1167                         if (idev) {
1168                                 struct inet6_ifaddr *ifp;
1169
1170                                 read_lock_bh(&idev->lock);
1171                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
1172                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
1173                                                 continue;
1174                                         np->local_ip.in6 = ifp->addr;
1175                                         err = 0;
1176                                         break;
1177                                 }
1178                                 read_unlock_bh(&idev->lock);
1179                         }
1180                         if (err) {
1181                                 np_err(np, "no IPv6 address for %s, aborting\n",
1182                                        np->dev_name);
1183                                 goto put;
1184                         } else
1185                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
1186 #else
1187                         np_err(np, "IPv6 is not supported %s, aborting\n",
1188                                np->dev_name);
1189                         err = -EINVAL;
1190                         goto put;
1191 #endif
1192                 }
1193         }
1194
1195         /* fill up the skb queue */
1196         refill_skbs();
1197
1198         err = __netpoll_setup(np, ndev, GFP_KERNEL);
1199         if (err)
1200                 goto put;
1201
1202         rtnl_unlock();
1203         return 0;
1204
1205 put:
1206         dev_put(ndev);
1207 unlock:
1208         rtnl_unlock();
1209         return err;
1210 }
1211 EXPORT_SYMBOL(netpoll_setup);
1212
1213 static int __init netpoll_init(void)
1214 {
1215         skb_queue_head_init(&skb_pool);
1216         return 0;
1217 }
1218 core_initcall(netpoll_init);
1219
1220 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
1221 {
1222         struct netpoll_info *npinfo =
1223                         container_of(rcu_head, struct netpoll_info, rcu);
1224
1225         skb_queue_purge(&npinfo->neigh_tx);
1226         skb_queue_purge(&npinfo->txq);
1227
1228         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
1229         cancel_delayed_work(&npinfo->tx_work);
1230
1231         /* clean after last, unfinished work */
1232         __skb_queue_purge(&npinfo->txq);
1233         /* now cancel it again */
1234         cancel_delayed_work(&npinfo->tx_work);
1235         kfree(npinfo);
1236 }
1237
1238 void __netpoll_cleanup(struct netpoll *np)
1239 {
1240         struct netpoll_info *npinfo;
1241         unsigned long flags;
1242
1243         /* rtnl_dereference would be preferable here but
1244          * rcu_cleanup_netpoll path can put us in here safely without
1245          * holding the rtnl, so plain rcu_dereference it is
1246          */
1247         npinfo = rtnl_dereference(np->dev->npinfo);
1248         if (!npinfo)
1249                 return;
1250
1251         if (!list_empty(&npinfo->rx_np)) {
1252                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1253                 list_del(&np->rx);
1254                 if (list_empty(&npinfo->rx_np))
1255                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
1256                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1257         }
1258
1259         synchronize_srcu(&netpoll_srcu);
1260
1261         if (atomic_dec_and_test(&npinfo->refcnt)) {
1262                 const struct net_device_ops *ops;
1263
1264                 ops = np->dev->netdev_ops;
1265                 if (ops->ndo_netpoll_cleanup)
1266                         ops->ndo_netpoll_cleanup(np->dev);
1267
1268                 rcu_assign_pointer(np->dev->npinfo, NULL);
1269                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
1270         }
1271 }
1272 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
1273
1274 static void netpoll_async_cleanup(struct work_struct *work)
1275 {
1276         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
1277
1278         rtnl_lock();
1279         __netpoll_cleanup(np);
1280         rtnl_unlock();
1281         kfree(np);
1282 }
1283
1284 void __netpoll_free_async(struct netpoll *np)
1285 {
1286         schedule_work(&np->cleanup_work);
1287 }
1288 EXPORT_SYMBOL_GPL(__netpoll_free_async);
1289
1290 void netpoll_cleanup(struct netpoll *np)
1291 {
1292         if (!np->dev)
1293                 return;
1294
1295         rtnl_lock();
1296         __netpoll_cleanup(np);
1297         rtnl_unlock();
1298
1299         dev_put(np->dev);
1300         np->dev = NULL;
1301 }
1302 EXPORT_SYMBOL(netpoll_cleanup);
1303
1304 int netpoll_trap(void)
1305 {
1306         return atomic_read(&trapped);
1307 }
1308 EXPORT_SYMBOL(netpoll_trap);
1309
1310 void netpoll_set_trap(int trap)
1311 {
1312         if (trap)
1313                 atomic_inc(&trapped);
1314         else
1315                 atomic_dec(&trapped);
1316 }
1317 EXPORT_SYMBOL(netpoll_set_trap);