net/core/netpoll.c

   1 /*
   2  * Common framework for low-level network console, dump, and debugger code
   3  *
   4  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
   5  *
   6  * based on the netconsole code from:
   7  *
   8  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
   9  * Copyright (C) 2002  Red Hat, Inc.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/moduleparam.h>
  15 #include <linux/kernel.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/string.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/inetdevice.h>
  21 #include <linux/inet.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/netpoll.h>
  24 #include <linux/sched.h>
  25 #include <linux/delay.h>
  26 #include <linux/rcupdate.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/slab.h>
  29 #include <linux/export.h>
  30 #include <linux/if_vlan.h>
  31 #include <net/tcp.h>
  32 #include <net/udp.h>
  33 #include <net/addrconf.h>
  34 #include <net/ndisc.h>
  35 #include <net/ip6_checksum.h>
  36 #include <asm/unaligned.h>
  37 #include <trace/events/napi.h>
  38
  39 /*
  40  * We maintain a small pool of fully-sized skbs, to make sure the
  41  * message gets out even in extreme OOM situations.
  42  */
  43
  44 #define MAX_UDP_CHUNK 1460
  45 #define MAX_SKBS 32
  46
  47 static struct sk_buff_head skb_pool;
  48
  49 #ifdef CONFIG_NETPOLL_TRAP
  50 static atomic_t trapped;
  51 #endif
  52
  53 DEFINE_STATIC_SRCU(netpoll_srcu);
  54
  55 #define USEC_PER_POLL   50
  56
  57 #define MAX_SKB_SIZE                                                    \
  58         (sizeof(struct ethhdr) +                                        \
  59          sizeof(struct iphdr) +                                         \
  60          sizeof(struct udphdr) +                                        \
  61          MAX_UDP_CHUNK)
  62
  63 static void zap_completion_queue(void);
  64 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo);
  65 static void netpoll_async_cleanup(struct work_struct *work);
  66
  67 static unsigned int carrier_timeout = 4;
  68 module_param(carrier_timeout, uint, 0644);
  69
  70 #define np_info(np, fmt, ...)                           \
  71         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  72 #define np_err(np, fmt, ...)                            \
  73         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  74 #define np_notice(np, fmt, ...)                         \
  75         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  76
  77 static void queue_process(struct work_struct *work)
  78 {
  79         struct netpoll_info *npinfo =
  80                 container_of(work, struct netpoll_info, tx_work.work);
  81         struct sk_buff *skb;
  82         unsigned long flags;
  83
  84         while ((skb = skb_dequeue(&npinfo->txq))) {
  85                 struct net_device *dev = skb->dev;
  86                 const struct net_device_ops *ops = dev->netdev_ops;
  87                 struct netdev_queue *txq;
  88
  89                 if (!netif_device_present(dev) || !netif_running(dev)) {
  90                         __kfree_skb(skb);
  91                         continue;
  92                 }
  93
  94                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  95
  96                 local_irq_save(flags);
  97                 __netif_tx_lock(txq, smp_processor_id());
  98                 if (netif_xmit_frozen_or_stopped(txq) ||
  99                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
 100                         skb_queue_head(&npinfo->txq, skb);
 101                         __netif_tx_unlock(txq);
 102                         local_irq_restore(flags);
 103
 104                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 105                         return;
 106                 }
 107                 __netif_tx_unlock(txq);
 108                 local_irq_restore(flags);
 109         }
 110 }
 111
 112 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 113                             unsigned short ulen, __be32 saddr, __be32 daddr)
 114 {
 115         __wsum psum;
 116
 117         if (uh->check == 0 || skb_csum_unnecessary(skb))
 118                 return 0;
 119
 120         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 121
 122         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 123             !csum_fold(csum_add(psum, skb->csum)))
 124                 return 0;
 125
 126         skb->csum = psum;
 127
 128         return __skb_checksum_complete(skb);
 129 }
 130
 131 /*
 132  * Check whether delayed processing was scheduled for our NIC. If so,
 133  * we attempt to grab the poll lock and use ->poll() to pump the card.
 134  * If this fails, either we've recursed in ->poll() or it's already
 135  * running on another CPU.
 136  *
 137  * Note: we don't mask interrupts with this lock because we're using
 138  * trylock here and interrupts are already disabled in the softirq
 139  * case. Further, we test the poll_owner to avoid recursion on UP
 140  * systems where the lock doesn't exist.
 141  *
 142  * In cases where there is bi-directional communications, reading only
 143  * one message at a time can lead to packets being dropped by the
 144  * network adapter, forcing superfluous retries and possibly timeouts.
 145  * Thus, we set our budget to greater than 1.
 146  */
 147 static int poll_one_napi(struct napi_struct *napi, int budget)
 148 {
 149         int work;
 150
 151         /* net_rx_action's ->poll() invocations and our's are
 152          * synchronized by this test which is only made while
 153          * holding the napi->poll_lock.
 154          */
 155         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 156                 return budget;
 157
 158         set_bit(NAPI_STATE_NPSVC, &napi->state);
 159
 160         work = napi->poll(napi, budget);
 161         WARN_ONCE(work > budget, "%pF exceeded budget in poll\n", napi->poll);
 162         trace_napi_poll(napi);
 163
 164         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 165
 166         return budget - work;
 167 }
 168
 169 static void poll_napi(struct net_device *dev, int budget)
 170 {
 171         struct napi_struct *napi;
 172
 173         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 174                 if (napi->poll_owner != smp_processor_id() &&
 175                     spin_trylock(&napi->poll_lock)) {
 176                         budget = poll_one_napi(napi, budget);
 177                         spin_unlock(&napi->poll_lock);
 178                 }
 179         }
 180 }
 181
 182 static void service_neigh_queue(struct net_device *dev,
 183                                 struct netpoll_info *npi)
 184 {
 185         struct sk_buff *skb;
 186         if (dev->flags & IFF_SLAVE) {
 187                 struct net_device *bond_dev;
 188                 struct netpoll_info *bond_ni;
 189
 190                 bond_dev = netdev_master_upper_dev_get_rcu(dev);
 191                 bond_ni = rcu_dereference_bh(bond_dev->npinfo);
 192                 while ((skb = skb_dequeue(&npi->neigh_tx))) {
 193                         skb->dev = bond_dev;
 194                         skb_queue_tail(&bond_ni->neigh_tx, skb);
 195                 }
 196         }
 197         while ((skb = skb_dequeue(&npi->neigh_tx)))
 198                 netpoll_neigh_reply(skb, npi);
 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         bool rx_processing = netpoll_rx_processing(ni);
 206         int budget = rx_processing? 16 : 0;
 207
 208         /* Don't do any rx activity if the dev_lock mutex is held
 209          * the dev_open/close paths use this to block netpoll activity
 210          * while changing device state
 211          */
 212         if (down_trylock(&ni->dev_lock))
 213                 return;
 214
 215         if (!netif_running(dev)) {
 216                 up(&ni->dev_lock);
 217                 return;
 218         }
 219
 220         if (rx_processing)
 221                 netpoll_set_trap(1);
 222
 223         ops = dev->netdev_ops;
 224         if (!ops->ndo_poll_controller) {
 225                 up(&ni->dev_lock);
 226                 return;
 227         }
 228
 229         /* Process pending work on NIC */
 230         ops->ndo_poll_controller(dev);
 231
 232         poll_napi(dev, budget);
 233
 234         if (rx_processing)
 235                 netpoll_set_trap(0);
 236
 237         up(&ni->dev_lock);
 238
 239         service_neigh_queue(dev, ni);
 240
 241         zap_completion_queue();
 242 }
 243
 244 void netpoll_rx_disable(struct net_device *dev)
 245 {
 246         struct netpoll_info *ni;
 247         int idx;
 248         might_sleep();
 249         idx = srcu_read_lock(&netpoll_srcu);
 250         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 251         if (ni)
 252                 down(&ni->dev_lock);
 253         srcu_read_unlock(&netpoll_srcu, idx);
 254 }
 255 EXPORT_SYMBOL(netpoll_rx_disable);
 256
 257 void netpoll_rx_enable(struct net_device *dev)
 258 {
 259         struct netpoll_info *ni;
 260         rcu_read_lock();
 261         ni = rcu_dereference(dev->npinfo);
 262         if (ni)
 263                 up(&ni->dev_lock);
 264         rcu_read_unlock();
 265 }
 266 EXPORT_SYMBOL(netpoll_rx_enable);
 267
 268 static void refill_skbs(void)
 269 {
 270         struct sk_buff *skb;
 271         unsigned long flags;
 272
 273         spin_lock_irqsave(&skb_pool.lock, flags);
 274         while (skb_pool.qlen < MAX_SKBS) {
 275                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 276                 if (!skb)
 277                         break;
 278
 279                 __skb_queue_tail(&skb_pool, skb);
 280         }
 281         spin_unlock_irqrestore(&skb_pool.lock, flags);
 282 }
 283
 284 static void zap_completion_queue(void)
 285 {
 286         unsigned long flags;
 287         struct softnet_data *sd = &get_cpu_var(softnet_data);
 288
 289         if (sd->completion_queue) {
 290                 struct sk_buff *clist;
 291
 292                 local_irq_save(flags);
 293                 clist = sd->completion_queue;
 294                 sd->completion_queue = NULL;
 295                 local_irq_restore(flags);
 296
 297                 while (clist != NULL) {
 298                         struct sk_buff *skb = clist;
 299                         clist = clist->next;
 300                         if (skb->destructor) {
 301                                 atomic_inc(&skb->users);
 302                                 dev_kfree_skb_any(skb); /* put this one back */
 303                         } else {
 304                                 __kfree_skb(skb);
 305                         }
 306                 }
 307         }
 308
 309         put_cpu_var(softnet_data);
 310 }
 311
 312 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 313 {
 314         int count = 0;
 315         struct sk_buff *skb;
 316
 317         zap_completion_queue();
 318         refill_skbs();
 319 repeat:
 320
 321         skb = alloc_skb(len, GFP_ATOMIC);
 322         if (!skb)
 323                 skb = skb_dequeue(&skb_pool);
 324
 325         if (!skb) {
 326                 if (++count < 10) {
 327                         netpoll_poll_dev(np->dev);
 328                         goto repeat;
 329                 }
 330                 return NULL;
 331         }
 332
 333         atomic_set(&skb->users, 1);
 334         skb_reserve(skb, reserve);
 335         return skb;
 336 }
 337
 338 static int netpoll_owner_active(struct net_device *dev)
 339 {
 340         struct napi_struct *napi;
 341
 342         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 343                 if (napi->poll_owner == smp_processor_id())
 344                         return 1;
 345         }
 346         return 0;
 347 }
 348
 349 /* call with IRQ disabled */
 350 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 351                              struct net_device *dev)
 352 {
 353         int status = NETDEV_TX_BUSY;
 354         unsigned long tries;
 355         const struct net_device_ops *ops = dev->netdev_ops;
 356         /* It is up to the caller to keep npinfo alive. */
 357         struct netpoll_info *npinfo;
 358
 359         WARN_ON_ONCE(!irqs_disabled());
 360
 361         npinfo = rcu_dereference_bh(np->dev->npinfo);
 362         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 363                 __kfree_skb(skb);
 364                 return;
 365         }
 366
 367         /* don't get messages out of order, and no recursion */
 368         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 369                 struct netdev_queue *txq;
 370
 371                 txq = netdev_pick_tx(dev, skb, NULL);
 372
 373                 /* try until next clock tick */
 374                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 375                      tries > 0; --tries) {
 376                         if (__netif_tx_trylock(txq)) {
 377                                 if (!netif_xmit_stopped(txq)) {
 378                                         if (vlan_tx_tag_present(skb) &&
 379                                             !vlan_hw_offload_capable(netif_skb_features(skb),
 380                                                                      skb->vlan_proto)) {
 381                                                 skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
 382                                                 if (unlikely(!skb)) {
 383                                                         /* This is actually a packet drop, but we
 384                                                          * don't want the code at the end of this
 385                                                          * function to try and re-queue a NULL skb.
 386                                                          */
 387                                                         status = NETDEV_TX_OK;
 388                                                         goto unlock_txq;
 389                                                 }
 390                                                 skb->vlan_tci = 0;
 391                                         }
 392
 393                                         status = ops->ndo_start_xmit(skb, dev);
 394                                         if (status == NETDEV_TX_OK)
 395                                                 txq_trans_update(txq);
 396                                 }
 397                         unlock_txq:
 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         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 517         ether_addr_copy(eth->h_dest, np->remote_mac);
 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 (!netpoll_rx_processing(npinfo))
 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_ARP) {
 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_skb_hooks for the same
 640                          * address we're fine by sending a single reply
 641                          */
 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                         hdr = (struct ipv6hdr *) skb_put(send_skb, sizeof(struct ipv6hdr));
 695                         *(__be32*)hdr = htonl(0x60000000);
 696                         hdr->payload_len = htons(size);
 697                         hdr->nexthdr = IPPROTO_ICMPV6;
 698                         hdr->hop_limit = 255;
 699                         hdr->saddr = *saddr;
 700                         hdr->daddr = *daddr;
 701
 702                         icmp6h = (struct icmp6hdr *) skb_put(send_skb, sizeof(struct icmp6hdr));
 703                         icmp6h->icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
 704                         icmp6h->icmp6_router = 0;
 705                         icmp6h->icmp6_solicited = 1;
 706
 707                         target = (struct in6_addr *) skb_put(send_skb, sizeof(struct in6_addr));
 708                         *target = msg->target;
 709                         icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, size,
 710                                                               IPPROTO_ICMPV6,
 711                                                               csum_partial(icmp6h,
 712                                                                            size, 0));
 713
 714                         if (dev_hard_header(send_skb, skb->dev, ETH_P_IPV6,
 715                                             lladdr, np->dev->dev_addr,
 716                                             send_skb->len) < 0) {
 717                                 kfree_skb(send_skb);
 718                                 continue;
 719                         }
 720
 721                         netpoll_send_skb(np, send_skb);
 722
 723                         /* If there are several rx_skb_hooks for the same
 724                          * address, we're fine by sending a single reply
 725                          */
 726                         break;
 727                 }
 728                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 729 #endif
 730         }
 731 }
 732
 733 static bool pkt_is_ns(struct sk_buff *skb)
 734 {
 735         struct nd_msg *msg;
 736         struct ipv6hdr *hdr;
 737
 738         if (skb->protocol != htons(ETH_P_ARP))
 739                 return false;
 740         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct nd_msg)))
 741                 return false;
 742
 743         msg = (struct nd_msg *)skb_transport_header(skb);
 744         __skb_push(skb, skb->data - skb_transport_header(skb));
 745         hdr = ipv6_hdr(skb);
 746
 747         if (hdr->nexthdr != IPPROTO_ICMPV6)
 748                 return false;
 749         if (hdr->hop_limit != 255)
 750                 return false;
 751         if (msg->icmph.icmp6_code != 0)
 752                 return false;
 753         if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 754                 return false;
 755
 756         return true;
 757 }
 758
 759 int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo)
 760 {
 761         int proto, len, ulen, data_len;
 762         int hits = 0, offset;
 763         const struct iphdr *iph;
 764         struct udphdr *uh;
 765         struct netpoll *np, *tmp;
 766         uint16_t source;
 767
 768         if (!netpoll_rx_processing(npinfo))
 769                 goto out;
 770
 771         if (skb->dev->type != ARPHRD_ETHER)
 772                 goto out;
 773
 774         /* check if netpoll clients need ARP */
 775         if (skb->protocol == htons(ETH_P_ARP) && netpoll_trap()) {
 776                 skb_queue_tail(&npinfo->neigh_tx, skb);
 777                 return 1;
 778         } else if (pkt_is_ns(skb) && netpoll_trap()) {
 779                 skb_queue_tail(&npinfo->neigh_tx, skb);
 780                 return 1;
 781         }
 782
 783         if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
 784                 skb = vlan_untag(skb);
 785                 if (unlikely(!skb))
 786                         goto out;
 787         }
 788
 789         proto = ntohs(eth_hdr(skb)->h_proto);
 790         if (proto != ETH_P_IP && proto != ETH_P_IPV6)
 791                 goto out;
 792         if (skb->pkt_type == PACKET_OTHERHOST)
 793                 goto out;
 794         if (skb_shared(skb))
 795                 goto out;
 796
 797         if (proto == ETH_P_IP) {
 798                 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 799                         goto out;
 800                 iph = (struct iphdr *)skb->data;
 801                 if (iph->ihl < 5 || iph->version != 4)
 802                         goto out;
 803                 if (!pskb_may_pull(skb, iph->ihl*4))
 804                         goto out;
 805                 iph = (struct iphdr *)skb->data;
 806                 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 807                         goto out;
 808
 809                 len = ntohs(iph->tot_len);
 810                 if (skb->len < len || len < iph->ihl*4)
 811                         goto out;
 812
 813                 /*
 814                  * Our transport medium may have padded the buffer out.
 815                  * Now We trim to the true length of the frame.
 816                  */
 817                 if (pskb_trim_rcsum(skb, len))
 818                         goto out;
 819
 820                 iph = (struct iphdr *)skb->data;
 821                 if (iph->protocol != IPPROTO_UDP)
 822                         goto out;
 823
 824                 len -= iph->ihl*4;
 825                 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 826                 offset = (unsigned char *)(uh + 1) - skb->data;
 827                 ulen = ntohs(uh->len);
 828                 data_len = skb->len - offset;
 829                 source = ntohs(uh->source);
 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_skb_hook(np, source, skb, offset, data_len);
 844                         hits++;
 845                 }
 846         } else {
 847 #if IS_ENABLED(CONFIG_IPV6)
 848                 const struct ipv6hdr *ip6h;
 849
 850                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 851                         goto out;
 852                 ip6h = (struct ipv6hdr *)skb->data;
 853                 if (ip6h->version != 6)
 854                         goto out;
 855                 len = ntohs(ip6h->payload_len);
 856                 if (!len)
 857                         goto out;
 858                 if (len + sizeof(struct ipv6hdr) > skb->len)
 859                         goto out;
 860                 if (pskb_trim_rcsum(skb, len + sizeof(struct ipv6hdr)))
 861                         goto out;
 862                 ip6h = ipv6_hdr(skb);
 863                 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 864                         goto out;
 865                 uh = udp_hdr(skb);
 866                 offset = (unsigned char *)(uh + 1) - skb->data;
 867                 ulen = ntohs(uh->len);
 868                 data_len = skb->len - offset;
 869                 source = ntohs(uh->source);
 870                 if (ulen != skb->len)
 871                         goto out;
 872                 if (udp6_csum_init(skb, uh, IPPROTO_UDP))
 873                         goto out;
 874                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 875                         if (!ipv6_addr_equal(&np->local_ip.in6, &ip6h->daddr))
 876                                 continue;
 877                         if (!ipv6_addr_equal(&np->remote_ip.in6, &ip6h->saddr))
 878                                 continue;
 879                         if (np->local_port && np->local_port != ntohs(uh->dest))
 880                                 continue;
 881
 882                         np->rx_skb_hook(np, source, skb, offset, data_len);
 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 (netpoll_trap()) {
 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         bool ipversion_set = false;
 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                 ipversion_set = true;
 958                 if ((delim = strchr(cur, '/')) == NULL)
 959                         goto parse_failed;
 960                 *delim = 0;
 961                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 962                 if (ipv6 < 0)
 963                         goto parse_failed;
 964                 else
 965                         np->ipv6 = (bool)ipv6;
 966                 cur = delim;
 967         }
 968         cur++;
 969
 970         if (*cur != ',') {
 971                 /* parse out dev name */
 972                 if ((delim = strchr(cur, ',')) == NULL)
 973                         goto parse_failed;
 974                 *delim = 0;
 975                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 976                 cur = delim;
 977         }
 978         cur++;
 979
 980         if (*cur != '@') {
 981                 /* dst port */
 982                 if ((delim = strchr(cur, '@')) == NULL)
 983                         goto parse_failed;
 984                 *delim = 0;
 985                 if (*cur == ' ' || *cur == '\t')
 986                         np_info(np, "warning: whitespace is not allowed\n");
 987                 if (kstrtou16(cur, 10, &np->remote_port))
 988                         goto parse_failed;
 989                 cur = delim;
 990         }
 991         cur++;
 992
 993         /* dst ip */
 994         if ((delim = strchr(cur, '/')) == NULL)
 995                 goto parse_failed;
 996         *delim = 0;
 997         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 998         if (ipv6 < 0)
 999                 goto parse_failed;
1000         else if (ipversion_set && np->ipv6 != (bool)ipv6)
1001                 goto parse_failed;
1002         else
1003                 np->ipv6 = (bool)ipv6;
1004         cur = delim + 1;
1005
1006         if (*cur != 0) {
1007                 /* MAC address */
1008                 if (!mac_pton(cur, np->remote_mac))
1009                         goto parse_failed;
1010         }
1011
1012         netpoll_print_options(np);
1013
1014         return 0;
1015
1016  parse_failed:
1017         np_info(np, "couldn't parse config at '%s'!\n", cur);
1018         return -1;
1019 }
1020 EXPORT_SYMBOL(netpoll_parse_options);
1021
1022 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
1023 {
1024         struct netpoll_info *npinfo;
1025         const struct net_device_ops *ops;
1026         unsigned long flags;
1027         int err;
1028
1029         np->dev = ndev;
1030         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
1031         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
1032
1033         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
1034             !ndev->netdev_ops->ndo_poll_controller) {
1035                 np_err(np, "%s doesn't support polling, aborting\n",
1036                        np->dev_name);
1037                 err = -ENOTSUPP;
1038                 goto out;
1039         }
1040
1041         if (!ndev->npinfo) {
1042                 npinfo = kmalloc(sizeof(*npinfo), gfp);
1043                 if (!npinfo) {
1044                         err = -ENOMEM;
1045                         goto out;
1046                 }
1047
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_skb_hook) {
1072                 spin_lock_irqsave(&npinfo->rx_lock, flags);
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                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1255         }
1256
1257         synchronize_srcu(&netpoll_srcu);
1258
1259         if (atomic_dec_and_test(&npinfo->refcnt)) {
1260                 const struct net_device_ops *ops;
1261
1262                 ops = np->dev->netdev_ops;
1263                 if (ops->ndo_netpoll_cleanup)
1264                         ops->ndo_netpoll_cleanup(np->dev);
1265
1266                 rcu_assign_pointer(np->dev->npinfo, NULL);
1267                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
1268         }
1269 }
1270 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
1271
1272 static void netpoll_async_cleanup(struct work_struct *work)
1273 {
1274         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
1275
1276         rtnl_lock();
1277         __netpoll_cleanup(np);
1278         rtnl_unlock();
1279         kfree(np);
1280 }
1281
1282 void __netpoll_free_async(struct netpoll *np)
1283 {
1284         schedule_work(&np->cleanup_work);
1285 }
1286 EXPORT_SYMBOL_GPL(__netpoll_free_async);
1287
1288 void netpoll_cleanup(struct netpoll *np)
1289 {
1290         rtnl_lock();
1291         if (!np->dev)
1292                 goto out;
1293         __netpoll_cleanup(np);
1294         dev_put(np->dev);
1295         np->dev = NULL;
1296 out:
1297         rtnl_unlock();
1298 }
1299 EXPORT_SYMBOL(netpoll_cleanup);
1300
1301 #ifdef CONFIG_NETPOLL_TRAP
1302 int netpoll_trap(void)
1303 {
1304         return atomic_read(&trapped);
1305 }
1306 EXPORT_SYMBOL(netpoll_trap);
1307
1308 void netpoll_set_trap(int trap)
1309 {
1310         if (trap)
1311                 atomic_inc(&trapped);
1312         else
1313                 atomic_dec(&trapped);
1314 }
1315 EXPORT_SYMBOL(netpoll_set_trap);
1316 #endif /* CONFIG_NETPOLL_TRAP */