net/core/netpoll.c

   1 /*
   2  * Common framework for low-level network console, dump, and debugger code
   3  *
   4  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
   5  *
   6  * based on the netconsole code from:
   7  *
   8  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
   9  * Copyright (C) 2002  Red Hat, Inc.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/moduleparam.h>
  15 #include <linux/kernel.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/string.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/inetdevice.h>
  21 #include <linux/inet.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/netpoll.h>
  24 #include <linux/sched.h>
  25 #include <linux/delay.h>
  26 #include <linux/rcupdate.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/slab.h>
  29 #include <linux/export.h>
  30 #include <linux/if_vlan.h>
  31 #include <net/tcp.h>
  32 #include <net/udp.h>
  33 #include <net/addrconf.h>
  34 #include <net/ndisc.h>
  35 #include <net/ip6_checksum.h>
  36 #include <asm/unaligned.h>
  37 #include <trace/events/napi.h>
  38
  39 /*
  40  * We maintain a small pool of fully-sized skbs, to make sure the
  41  * message gets out even in extreme OOM situations.
  42  */
  43
  44 #define MAX_UDP_CHUNK 1460
  45 #define MAX_SKBS 32
  46
  47 static struct sk_buff_head skb_pool;
  48
  49 static atomic_t trapped;
  50
  51 DEFINE_STATIC_SRCU(netpoll_srcu);
  52
  53 #define USEC_PER_POLL   50
  54 #define NETPOLL_RX_ENABLED  1
  55 #define NETPOLL_RX_DROP     2
  56
  57 #define MAX_SKB_SIZE                                                    \
  58         (sizeof(struct ethhdr) +                                        \
  59          sizeof(struct iphdr) +                                         \
  60          sizeof(struct udphdr) +                                        \
  61          MAX_UDP_CHUNK)
  62
  63 static void zap_completion_queue(void);
  64 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo);
  65 static void netpoll_async_cleanup(struct work_struct *work);
  66
  67 static unsigned int carrier_timeout = 4;
  68 module_param(carrier_timeout, uint, 0644);
  69
  70 #define np_info(np, fmt, ...)                           \
  71         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  72 #define np_err(np, fmt, ...)                            \
  73         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  74 #define np_notice(np, fmt, ...)                         \
  75         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  76
  77 static void queue_process(struct work_struct *work)
  78 {
  79         struct netpoll_info *npinfo =
  80                 container_of(work, struct netpoll_info, tx_work.work);
  81         struct sk_buff *skb;
  82         unsigned long flags;
  83
  84         while ((skb = skb_dequeue(&npinfo->txq))) {
  85                 struct net_device *dev = skb->dev;
  86                 const struct net_device_ops *ops = dev->netdev_ops;
  87                 struct netdev_queue *txq;
  88
  89                 if (!netif_device_present(dev) || !netif_running(dev)) {
  90                         __kfree_skb(skb);
  91                         continue;
  92                 }
  93
  94                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  95
  96                 local_irq_save(flags);
  97                 __netif_tx_lock(txq, smp_processor_id());
  98                 if (netif_xmit_frozen_or_stopped(txq) ||
  99                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
 100                         skb_queue_head(&npinfo->txq, skb);
 101                         __netif_tx_unlock(txq);
 102                         local_irq_restore(flags);
 103
 104                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 105                         return;
 106                 }
 107                 __netif_tx_unlock(txq);
 108                 local_irq_restore(flags);
 109         }
 110 }
 111
 112 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 113                             unsigned short ulen, __be32 saddr, __be32 daddr)
 114 {
 115         __wsum psum;
 116
 117         if (uh->check == 0 || skb_csum_unnecessary(skb))
 118                 return 0;
 119
 120         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 121
 122         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 123             !csum_fold(csum_add(psum, skb->csum)))
 124                 return 0;
 125
 126         skb->csum = psum;
 127
 128         return __skb_checksum_complete(skb);
 129 }
 130
 131 /*
 132  * Check whether delayed processing was scheduled for our NIC. If so,
 133  * we attempt to grab the poll lock and use ->poll() to pump the card.
 134  * If this fails, either we've recursed in ->poll() or it's already
 135  * running on another CPU.
 136  *
 137  * Note: we don't mask interrupts with this lock because we're using
 138  * trylock here and interrupts are already disabled in the softirq
 139  * case. Further, we test the poll_owner to avoid recursion on UP
 140  * systems where the lock doesn't exist.
 141  *
 142  * In cases where there is bi-directional communications, reading only
 143  * one message at a time can lead to packets being dropped by the
 144  * network adapter, forcing superfluous retries and possibly timeouts.
 145  * Thus, we set our budget to greater than 1.
 146  */
 147 static int poll_one_napi(struct napi_struct *napi, int budget)
 148 {
 149         int work;
 150
 151         /* net_rx_action's ->poll() invocations and our's are
 152          * synchronized by this test which is only made while
 153          * holding the napi->poll_lock.
 154          */
 155         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 156                 return budget;
 157
 158         set_bit(NAPI_STATE_NPSVC, &napi->state);
 159
 160         work = napi->poll(napi, budget);
 161         WARN_ONCE(work > budget, "%pF exceeded budget in poll\n", napi->poll);
 162         trace_napi_poll(napi);
 163
 164         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 165
 166         return budget - work;
 167 }
 168
 169 static void poll_napi(struct net_device *dev, int budget)
 170 {
 171         struct napi_struct *napi;
 172
 173         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 174                 if (napi->poll_owner != smp_processor_id() &&
 175                     spin_trylock(&napi->poll_lock)) {
 176                         budget = poll_one_napi(napi, budget);
 177                         spin_unlock(&napi->poll_lock);
 178                 }
 179         }
 180 }
 181
 182 static void service_neigh_queue(struct netpoll_info *npi)
 183 {
 184         if (npi) {
 185                 struct sk_buff *skb;
 186
 187                 while ((skb = skb_dequeue(&npi->neigh_tx)))
 188                         netpoll_neigh_reply(skb, npi);
 189         }
 190 }
 191
 192 static void netpoll_poll_dev(struct net_device *dev)
 193 {
 194         const struct net_device_ops *ops;
 195         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 196         int budget = 16;
 197
 198         /* Don't do any rx activity if the dev_lock mutex is held
 199          * the dev_open/close paths use this to block netpoll activity
 200          * while changing device state
 201          */
 202         if (down_trylock(&ni->dev_lock))
 203                 return;
 204
 205         if (!netif_running(dev)) {
 206                 up(&ni->dev_lock);
 207                 return;
 208         }
 209
 210         ni->rx_flags |= NETPOLL_RX_DROP;
 211         atomic_inc(&trapped);
 212
 213         ops = dev->netdev_ops;
 214         if (!ops->ndo_poll_controller) {
 215                 up(&ni->dev_lock);
 216                 return;
 217         }
 218
 219         /* Process pending work on NIC */
 220         ops->ndo_poll_controller(dev);
 221
 222         poll_napi(dev, budget);
 223
 224         atomic_dec(&trapped);
 225         ni->rx_flags &= ~NETPOLL_RX_DROP;
 226
 227         up(&ni->dev_lock);
 228
 229         if (dev->flags & IFF_SLAVE) {
 230                 if (ni) {
 231                         struct net_device *bond_dev;
 232                         struct sk_buff *skb;
 233                         struct netpoll_info *bond_ni;
 234
 235                         bond_dev = netdev_master_upper_dev_get_rcu(dev);
 236                         bond_ni = rcu_dereference_bh(bond_dev->npinfo);
 237                         while ((skb = skb_dequeue(&ni->neigh_tx))) {
 238                                 skb->dev = bond_dev;
 239                                 skb_queue_tail(&bond_ni->neigh_tx, skb);
 240                         }
 241                 }
 242         }
 243
 244         service_neigh_queue(ni);
 245
 246         zap_completion_queue();
 247 }
 248
 249 void netpoll_rx_disable(struct net_device *dev)
 250 {
 251         struct netpoll_info *ni;
 252         int idx;
 253         might_sleep();
 254         idx = srcu_read_lock(&netpoll_srcu);
 255         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 256         if (ni)
 257                 down(&ni->dev_lock);
 258         srcu_read_unlock(&netpoll_srcu, idx);
 259 }
 260 EXPORT_SYMBOL(netpoll_rx_disable);
 261
 262 void netpoll_rx_enable(struct net_device *dev)
 263 {
 264         struct netpoll_info *ni;
 265         rcu_read_lock();
 266         ni = rcu_dereference(dev->npinfo);
 267         if (ni)
 268                 up(&ni->dev_lock);
 269         rcu_read_unlock();
 270 }
 271 EXPORT_SYMBOL(netpoll_rx_enable);
 272
 273 static void refill_skbs(void)
 274 {
 275         struct sk_buff *skb;
 276         unsigned long flags;
 277
 278         spin_lock_irqsave(&skb_pool.lock, flags);
 279         while (skb_pool.qlen < MAX_SKBS) {
 280                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 281                 if (!skb)
 282                         break;
 283
 284                 __skb_queue_tail(&skb_pool, skb);
 285         }
 286         spin_unlock_irqrestore(&skb_pool.lock, flags);
 287 }
 288
 289 static void zap_completion_queue(void)
 290 {
 291         unsigned long flags;
 292         struct softnet_data *sd = &get_cpu_var(softnet_data);
 293
 294         if (sd->completion_queue) {
 295                 struct sk_buff *clist;
 296
 297                 local_irq_save(flags);
 298                 clist = sd->completion_queue;
 299                 sd->completion_queue = NULL;
 300                 local_irq_restore(flags);
 301
 302                 while (clist != NULL) {
 303                         struct sk_buff *skb = clist;
 304                         clist = clist->next;
 305                         if (skb->destructor) {
 306                                 atomic_inc(&skb->users);
 307                                 dev_kfree_skb_any(skb); /* put this one back */
 308                         } else {
 309                                 __kfree_skb(skb);
 310                         }
 311                 }
 312         }
 313
 314         put_cpu_var(softnet_data);
 315 }
 316
 317 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 318 {
 319         int count = 0;
 320         struct sk_buff *skb;
 321
 322         zap_completion_queue();
 323         refill_skbs();
 324 repeat:
 325
 326         skb = alloc_skb(len, GFP_ATOMIC);
 327         if (!skb)
 328                 skb = skb_dequeue(&skb_pool);
 329
 330         if (!skb) {
 331                 if (++count < 10) {
 332                         netpoll_poll_dev(np->dev);
 333                         goto repeat;
 334                 }
 335                 return NULL;
 336         }
 337
 338         atomic_set(&skb->users, 1);
 339         skb_reserve(skb, reserve);
 340         return skb;
 341 }
 342
 343 static int netpoll_owner_active(struct net_device *dev)
 344 {
 345         struct napi_struct *napi;
 346
 347         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 348                 if (napi->poll_owner == smp_processor_id())
 349                         return 1;
 350         }
 351         return 0;
 352 }
 353
 354 /* call with IRQ disabled */
 355 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 356                              struct net_device *dev)
 357 {
 358         int status = NETDEV_TX_BUSY;
 359         unsigned long tries;
 360         const struct net_device_ops *ops = dev->netdev_ops;
 361         /* It is up to the caller to keep npinfo alive. */
 362         struct netpoll_info *npinfo;
 363
 364         WARN_ON_ONCE(!irqs_disabled());
 365
 366         npinfo = rcu_dereference_bh(np->dev->npinfo);
 367         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 368                 __kfree_skb(skb);
 369                 return;
 370         }
 371
 372         /* don't get messages out of order, and no recursion */
 373         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 374                 struct netdev_queue *txq;
 375
 376                 txq = netdev_pick_tx(dev, skb, NULL);
 377
 378                 /* try until next clock tick */
 379                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 380                      tries > 0; --tries) {
 381                         if (__netif_tx_trylock(txq)) {
 382                                 if (!netif_xmit_stopped(txq)) {
 383                                         if (vlan_tx_tag_present(skb) &&
 384                                             !vlan_hw_offload_capable(netif_skb_features(skb),
 385                                                                      skb->vlan_proto)) {
 386                                                 skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
 387                                                 if (unlikely(!skb)) {
 388                                                         /* This is actually a packet drop, but we
 389                                                          * don't want the code at the end of this
 390                                                          * function to try and re-queue a NULL skb.
 391                                                          */
 392                                                         status = NETDEV_TX_OK;
 393                                                         goto unlock_txq;
 394                                                 }
 395                                                 skb->vlan_tci = 0;
 396                                         }
 397
 398                                         status = ops->ndo_start_xmit(skb, dev);
 399                                         if (status == NETDEV_TX_OK)
 400                                                 txq_trans_update(txq);
 401                                 }
 402                         unlock_txq:
 403                                 __netif_tx_unlock(txq);
 404
 405                                 if (status == NETDEV_TX_OK)
 406                                         break;
 407
 408                         }
 409
 410                         /* tickle device maybe there is some cleanup */
 411                         netpoll_poll_dev(np->dev);
 412
 413                         udelay(USEC_PER_POLL);
 414                 }
 415
 416                 WARN_ONCE(!irqs_disabled(),
 417                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 418                         dev->name, ops->ndo_start_xmit);
 419
 420         }
 421
 422         if (status != NETDEV_TX_OK) {
 423                 skb_queue_tail(&npinfo->txq, skb);
 424                 schedule_delayed_work(&npinfo->tx_work,0);
 425         }
 426 }
 427 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 428
 429 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 430 {
 431         int total_len, ip_len, udp_len;
 432         struct sk_buff *skb;
 433         struct udphdr *udph;
 434         struct iphdr *iph;
 435         struct ethhdr *eth;
 436         static atomic_t ip_ident;
 437         struct ipv6hdr *ip6h;
 438
 439         udp_len = len + sizeof(*udph);
 440         if (np->ipv6)
 441                 ip_len = udp_len + sizeof(*ip6h);
 442         else
 443                 ip_len = udp_len + sizeof(*iph);
 444
 445         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 446
 447         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 448                        total_len - len);
 449         if (!skb)
 450                 return;
 451
 452         skb_copy_to_linear_data(skb, msg, len);
 453         skb_put(skb, len);
 454
 455         skb_push(skb, sizeof(*udph));
 456         skb_reset_transport_header(skb);
 457         udph = udp_hdr(skb);
 458         udph->source = htons(np->local_port);
 459         udph->dest = htons(np->remote_port);
 460         udph->len = htons(udp_len);
 461
 462         if (np->ipv6) {
 463                 udph->check = 0;
 464                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 465                                               &np->remote_ip.in6,
 466                                               udp_len, IPPROTO_UDP,
 467                                               csum_partial(udph, udp_len, 0));
 468                 if (udph->check == 0)
 469                         udph->check = CSUM_MANGLED_0;
 470
 471                 skb_push(skb, sizeof(*ip6h));
 472                 skb_reset_network_header(skb);
 473                 ip6h = ipv6_hdr(skb);
 474
 475                 /* ip6h->version = 6; ip6h->priority = 0; */
 476                 put_unaligned(0x60, (unsigned char *)ip6h);
 477                 ip6h->flow_lbl[0] = 0;
 478                 ip6h->flow_lbl[1] = 0;
 479                 ip6h->flow_lbl[2] = 0;
 480
 481                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 482                 ip6h->nexthdr = IPPROTO_UDP;
 483                 ip6h->hop_limit = 32;
 484                 ip6h->saddr = np->local_ip.in6;
 485                 ip6h->daddr = np->remote_ip.in6;
 486
 487                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 488                 skb_reset_mac_header(skb);
 489                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 490         } else {
 491                 udph->check = 0;
 492                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 493                                                 np->remote_ip.ip,
 494                                                 udp_len, IPPROTO_UDP,
 495                                                 csum_partial(udph, udp_len, 0));
 496                 if (udph->check == 0)
 497                         udph->check = CSUM_MANGLED_0;
 498
 499                 skb_push(skb, sizeof(*iph));
 500                 skb_reset_network_header(skb);
 501                 iph = ip_hdr(skb);
 502
 503                 /* iph->version = 4; iph->ihl = 5; */
 504                 put_unaligned(0x45, (unsigned char *)iph);
 505                 iph->tos      = 0;
 506                 put_unaligned(htons(ip_len), &(iph->tot_len));
 507                 iph->id       = htons(atomic_inc_return(&ip_ident));
 508                 iph->frag_off = 0;
 509                 iph->ttl      = 64;
 510                 iph->protocol = IPPROTO_UDP;
 511                 iph->check    = 0;
 512                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 513                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 514                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 515
 516                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 517                 skb_reset_mac_header(skb);
 518                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 519         }
 520
 521         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 522         ether_addr_copy(eth->h_dest, np->remote_mac);
 523
 524         skb->dev = np->dev;
 525
 526         netpoll_send_skb(np, skb);
 527 }
 528 EXPORT_SYMBOL(netpoll_send_udp);
 529
 530 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo)
 531 {
 532         int size, type = ARPOP_REPLY;
 533         __be32 sip, tip;
 534         unsigned char *sha;
 535         struct sk_buff *send_skb;
 536         struct netpoll *np, *tmp;
 537         unsigned long flags;
 538         int hlen, tlen;
 539         int hits = 0, proto;
 540
 541         if (!netpoll_rx_processing(npinfo))
 542                 return;
 543
 544         /* Before checking the packet, we do some early
 545            inspection whether this is interesting at all */
 546         spin_lock_irqsave(&npinfo->rx_lock, flags);
 547         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 548                 if (np->dev == skb->dev)
 549                         hits++;
 550         }
 551         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 552
 553         /* No netpoll struct is using this dev */
 554         if (!hits)
 555                 return;
 556
 557         proto = ntohs(eth_hdr(skb)->h_proto);
 558         if (proto == ETH_P_ARP) {
 559                 struct arphdr *arp;
 560                 unsigned char *arp_ptr;
 561                 /* No arp on this interface */
 562                 if (skb->dev->flags & IFF_NOARP)
 563                         return;
 564
 565                 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 566                         return;
 567
 568                 skb_reset_network_header(skb);
 569                 skb_reset_transport_header(skb);
 570                 arp = arp_hdr(skb);
 571
 572                 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 573                      arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 574                     arp->ar_pro != htons(ETH_P_IP) ||
 575                     arp->ar_op != htons(ARPOP_REQUEST))
 576                         return;
 577
 578                 arp_ptr = (unsigned char *)(arp+1);
 579                 /* save the location of the src hw addr */
 580                 sha = arp_ptr;
 581                 arp_ptr += skb->dev->addr_len;
 582                 memcpy(&sip, arp_ptr, 4);
 583                 arp_ptr += 4;
 584                 /* If we actually cared about dst hw addr,
 585                    it would get copied here */
 586                 arp_ptr += skb->dev->addr_len;
 587                 memcpy(&tip, arp_ptr, 4);
 588
 589                 /* Should we ignore arp? */
 590                 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 591                         return;
 592
 593                 size = arp_hdr_len(skb->dev);
 594
 595                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 596                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 597                         if (tip != np->local_ip.ip)
 598                                 continue;
 599
 600                         hlen = LL_RESERVED_SPACE(np->dev);
 601                         tlen = np->dev->needed_tailroom;
 602                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 603                         if (!send_skb)
 604                                 continue;
 605
 606                         skb_reset_network_header(send_skb);
 607                         arp = (struct arphdr *) skb_put(send_skb, size);
 608                         send_skb->dev = skb->dev;
 609                         send_skb->protocol = htons(ETH_P_ARP);
 610
 611                         /* Fill the device header for the ARP frame */
 612                         if (dev_hard_header(send_skb, skb->dev, ETH_P_ARP,
 613                                             sha, np->dev->dev_addr,
 614                                             send_skb->len) < 0) {
 615                                 kfree_skb(send_skb);
 616                                 continue;
 617                         }
 618
 619                         /*
 620                          * Fill out the arp protocol part.
 621                          *
 622                          * we only support ethernet device type,
 623                          * which (according to RFC 1390) should
 624                          * always equal 1 (Ethernet).
 625                          */
 626
 627                         arp->ar_hrd = htons(np->dev->type);
 628                         arp->ar_pro = htons(ETH_P_IP);
 629                         arp->ar_hln = np->dev->addr_len;
 630                         arp->ar_pln = 4;
 631                         arp->ar_op = htons(type);
 632
 633                         arp_ptr = (unsigned char *)(arp + 1);
 634                         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 635                         arp_ptr += np->dev->addr_len;
 636                         memcpy(arp_ptr, &tip, 4);
 637                         arp_ptr += 4;
 638                         memcpy(arp_ptr, sha, np->dev->addr_len);
 639                         arp_ptr += np->dev->addr_len;
 640                         memcpy(arp_ptr, &sip, 4);
 641
 642                         netpoll_send_skb(np, send_skb);
 643
 644                         /* If there are several rx_skb_hooks for the same
 645                          * address we're fine by sending a single reply
 646                          */
 647                         break;
 648                 }
 649                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 650         } else if( proto == ETH_P_IPV6) {
 651 #if IS_ENABLED(CONFIG_IPV6)
 652                 struct nd_msg *msg;
 653                 u8 *lladdr = NULL;
 654                 struct ipv6hdr *hdr;
 655                 struct icmp6hdr *icmp6h;
 656                 const struct in6_addr *saddr;
 657                 const struct in6_addr *daddr;
 658                 struct inet6_dev *in6_dev = NULL;
 659                 struct in6_addr *target;
 660
 661                 in6_dev = in6_dev_get(skb->dev);
 662                 if (!in6_dev || !in6_dev->cnf.accept_ra)
 663                         return;
 664
 665                 if (!pskb_may_pull(skb, skb->len))
 666                         return;
 667
 668                 msg = (struct nd_msg *)skb_transport_header(skb);
 669
 670                 __skb_push(skb, skb->data - skb_transport_header(skb));
 671
 672                 if (ipv6_hdr(skb)->hop_limit != 255)
 673                         return;
 674                 if (msg->icmph.icmp6_code != 0)
 675                         return;
 676                 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 677                         return;
 678
 679                 saddr = &ipv6_hdr(skb)->saddr;
 680                 daddr = &ipv6_hdr(skb)->daddr;
 681
 682                 size = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
 683
 684                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 685                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 686                         if (!ipv6_addr_equal(daddr, &np->local_ip.in6))
 687                                 continue;
 688
 689                         hlen = LL_RESERVED_SPACE(np->dev);
 690                         tlen = np->dev->needed_tailroom;
 691                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 692                         if (!send_skb)
 693                                 continue;
 694
 695                         send_skb->protocol = htons(ETH_P_IPV6);
 696                         send_skb->dev = skb->dev;
 697
 698                         skb_reset_network_header(send_skb);
 699                         hdr = (struct ipv6hdr *) skb_put(send_skb, sizeof(struct ipv6hdr));
 700                         *(__be32*)hdr = htonl(0x60000000);
 701                         hdr->payload_len = htons(size);
 702                         hdr->nexthdr = IPPROTO_ICMPV6;
 703                         hdr->hop_limit = 255;
 704                         hdr->saddr = *saddr;
 705                         hdr->daddr = *daddr;
 706
 707                         icmp6h = (struct icmp6hdr *) skb_put(send_skb, sizeof(struct icmp6hdr));
 708                         icmp6h->icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
 709                         icmp6h->icmp6_router = 0;
 710                         icmp6h->icmp6_solicited = 1;
 711
 712                         target = (struct in6_addr *) skb_put(send_skb, sizeof(struct in6_addr));
 713                         *target = msg->target;
 714                         icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, size,
 715                                                               IPPROTO_ICMPV6,
 716                                                               csum_partial(icmp6h,
 717                                                                            size, 0));
 718
 719                         if (dev_hard_header(send_skb, skb->dev, ETH_P_IPV6,
 720                                             lladdr, np->dev->dev_addr,
 721                                             send_skb->len) < 0) {
 722                                 kfree_skb(send_skb);
 723                                 continue;
 724                         }
 725
 726                         netpoll_send_skb(np, send_skb);
 727
 728                         /* If there are several rx_skb_hooks for the same
 729                          * address, we're fine by sending a single reply
 730                          */
 731                         break;
 732                 }
 733                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 734 #endif
 735         }
 736 }
 737
 738 static bool pkt_is_ns(struct sk_buff *skb)
 739 {
 740         struct nd_msg *msg;
 741         struct ipv6hdr *hdr;
 742
 743         if (skb->protocol != htons(ETH_P_ARP))
 744                 return false;
 745         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct nd_msg)))
 746                 return false;
 747
 748         msg = (struct nd_msg *)skb_transport_header(skb);
 749         __skb_push(skb, skb->data - skb_transport_header(skb));
 750         hdr = ipv6_hdr(skb);
 751
 752         if (hdr->nexthdr != IPPROTO_ICMPV6)
 753                 return false;
 754         if (hdr->hop_limit != 255)
 755                 return false;
 756         if (msg->icmph.icmp6_code != 0)
 757                 return false;
 758         if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 759                 return false;
 760
 761         return true;
 762 }
 763
 764 int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo)
 765 {
 766         int proto, len, ulen, data_len;
 767         int hits = 0, offset;
 768         const struct iphdr *iph;
 769         struct udphdr *uh;
 770         struct netpoll *np, *tmp;
 771         uint16_t source;
 772
 773         if (!netpoll_rx_processing(npinfo))
 774                 goto out;
 775
 776         if (skb->dev->type != ARPHRD_ETHER)
 777                 goto out;
 778
 779         /* check if netpoll clients need ARP */
 780         if (skb->protocol == htons(ETH_P_ARP) && atomic_read(&trapped)) {
 781                 skb_queue_tail(&npinfo->neigh_tx, skb);
 782                 return 1;
 783         } else if (pkt_is_ns(skb) && atomic_read(&trapped)) {
 784                 skb_queue_tail(&npinfo->neigh_tx, skb);
 785                 return 1;
 786         }
 787
 788         if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
 789                 skb = vlan_untag(skb);
 790                 if (unlikely(!skb))
 791                         goto out;
 792         }
 793
 794         proto = ntohs(eth_hdr(skb)->h_proto);
 795         if (proto != ETH_P_IP && proto != ETH_P_IPV6)
 796                 goto out;
 797         if (skb->pkt_type == PACKET_OTHERHOST)
 798                 goto out;
 799         if (skb_shared(skb))
 800                 goto out;
 801
 802         if (proto == ETH_P_IP) {
 803                 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 804                         goto out;
 805                 iph = (struct iphdr *)skb->data;
 806                 if (iph->ihl < 5 || iph->version != 4)
 807                         goto out;
 808                 if (!pskb_may_pull(skb, iph->ihl*4))
 809                         goto out;
 810                 iph = (struct iphdr *)skb->data;
 811                 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 812                         goto out;
 813
 814                 len = ntohs(iph->tot_len);
 815                 if (skb->len < len || len < iph->ihl*4)
 816                         goto out;
 817
 818                 /*
 819                  * Our transport medium may have padded the buffer out.
 820                  * Now We trim to the true length of the frame.
 821                  */
 822                 if (pskb_trim_rcsum(skb, len))
 823                         goto out;
 824
 825                 iph = (struct iphdr *)skb->data;
 826                 if (iph->protocol != IPPROTO_UDP)
 827                         goto out;
 828
 829                 len -= iph->ihl*4;
 830                 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 831                 offset = (unsigned char *)(uh + 1) - skb->data;
 832                 ulen = ntohs(uh->len);
 833                 data_len = skb->len - offset;
 834                 source = ntohs(uh->source);
 835
 836                 if (ulen != len)
 837                         goto out;
 838                 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 839                         goto out;
 840                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 841                         if (np->local_ip.ip && np->local_ip.ip != iph->daddr)
 842                                 continue;
 843                         if (np->remote_ip.ip && np->remote_ip.ip != iph->saddr)
 844                                 continue;
 845                         if (np->local_port && np->local_port != ntohs(uh->dest))
 846                                 continue;
 847
 848                         np->rx_skb_hook(np, source, skb, offset, data_len);
 849                         hits++;
 850                 }
 851         } else {
 852 #if IS_ENABLED(CONFIG_IPV6)
 853                 const struct ipv6hdr *ip6h;
 854
 855                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 856                         goto out;
 857                 ip6h = (struct ipv6hdr *)skb->data;
 858                 if (ip6h->version != 6)
 859                         goto out;
 860                 len = ntohs(ip6h->payload_len);
 861                 if (!len)
 862                         goto out;
 863                 if (len + sizeof(struct ipv6hdr) > skb->len)
 864                         goto out;
 865                 if (pskb_trim_rcsum(skb, len + sizeof(struct ipv6hdr)))
 866                         goto out;
 867                 ip6h = ipv6_hdr(skb);
 868                 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 869                         goto out;
 870                 uh = udp_hdr(skb);
 871                 offset = (unsigned char *)(uh + 1) - skb->data;
 872                 ulen = ntohs(uh->len);
 873                 data_len = skb->len - offset;
 874                 source = ntohs(uh->source);
 875                 if (ulen != skb->len)
 876                         goto out;
 877                 if (udp6_csum_init(skb, uh, IPPROTO_UDP))
 878                         goto out;
 879                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 880                         if (!ipv6_addr_equal(&np->local_ip.in6, &ip6h->daddr))
 881                                 continue;
 882                         if (!ipv6_addr_equal(&np->remote_ip.in6, &ip6h->saddr))
 883                                 continue;
 884                         if (np->local_port && np->local_port != ntohs(uh->dest))
 885                                 continue;
 886
 887                         np->rx_skb_hook(np, source, skb, offset, data_len);
 888                         hits++;
 889                 }
 890 #endif
 891         }
 892
 893         if (!hits)
 894                 goto out;
 895
 896         kfree_skb(skb);
 897         return 1;
 898
 899 out:
 900         if (atomic_read(&trapped)) {
 901                 kfree_skb(skb);
 902                 return 1;
 903         }
 904
 905         return 0;
 906 }
 907
 908 void netpoll_print_options(struct netpoll *np)
 909 {
 910         np_info(np, "local port %d\n", np->local_port);
 911         if (np->ipv6)
 912                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 913         else
 914                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 915         np_info(np, "interface '%s'\n", np->dev_name);
 916         np_info(np, "remote port %d\n", np->remote_port);
 917         if (np->ipv6)
 918                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 919         else
 920                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 921         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 922 }
 923 EXPORT_SYMBOL(netpoll_print_options);
 924
 925 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 926 {
 927         const char *end;
 928
 929         if (!strchr(str, ':') &&
 930             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 931                 if (!*end)
 932                         return 0;
 933         }
 934         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 935 #if IS_ENABLED(CONFIG_IPV6)
 936                 if (!*end)
 937                         return 1;
 938 #else
 939                 return -1;
 940 #endif
 941         }
 942         return -1;
 943 }
 944
 945 int netpoll_parse_options(struct netpoll *np, char *opt)
 946 {
 947         char *cur=opt, *delim;
 948         int ipv6;
 949         bool ipversion_set = false;
 950
 951         if (*cur != '@') {
 952                 if ((delim = strchr(cur, '@')) == NULL)
 953                         goto parse_failed;
 954                 *delim = 0;
 955                 if (kstrtou16(cur, 10, &np->local_port))
 956                         goto parse_failed;
 957                 cur = delim;
 958         }
 959         cur++;
 960
 961         if (*cur != '/') {
 962                 ipversion_set = true;
 963                 if ((delim = strchr(cur, '/')) == NULL)
 964                         goto parse_failed;
 965                 *delim = 0;
 966                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 967                 if (ipv6 < 0)
 968                         goto parse_failed;
 969                 else
 970                         np->ipv6 = (bool)ipv6;
 971                 cur = delim;
 972         }
 973         cur++;
 974
 975         if (*cur != ',') {
 976                 /* parse out dev name */
 977                 if ((delim = strchr(cur, ',')) == NULL)
 978                         goto parse_failed;
 979                 *delim = 0;
 980                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 981                 cur = delim;
 982         }
 983         cur++;
 984
 985         if (*cur != '@') {
 986                 /* dst port */
 987                 if ((delim = strchr(cur, '@')) == NULL)
 988                         goto parse_failed;
 989                 *delim = 0;
 990                 if (*cur == ' ' || *cur == '\t')
 991                         np_info(np, "warning: whitespace is not allowed\n");
 992                 if (kstrtou16(cur, 10, &np->remote_port))
 993                         goto parse_failed;
 994                 cur = delim;
 995         }
 996         cur++;
 997
 998         /* dst ip */
 999         if ((delim = strchr(cur, '/')) == NULL)
1000                 goto parse_failed;
1001         *delim = 0;
1002         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
1003         if (ipv6 < 0)
1004                 goto parse_failed;
1005         else if (ipversion_set && np->ipv6 != (bool)ipv6)
1006                 goto parse_failed;
1007         else
1008                 np->ipv6 = (bool)ipv6;
1009         cur = delim + 1;
1010
1011         if (*cur != 0) {
1012                 /* MAC address */
1013                 if (!mac_pton(cur, np->remote_mac))
1014                         goto parse_failed;
1015         }
1016
1017         netpoll_print_options(np);
1018
1019         return 0;
1020
1021  parse_failed:
1022         np_info(np, "couldn't parse config at '%s'!\n", cur);
1023         return -1;
1024 }
1025 EXPORT_SYMBOL(netpoll_parse_options);
1026
1027 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
1028 {
1029         struct netpoll_info *npinfo;
1030         const struct net_device_ops *ops;
1031         unsigned long flags;
1032         int err;
1033
1034         np->dev = ndev;
1035         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
1036         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
1037
1038         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
1039             !ndev->netdev_ops->ndo_poll_controller) {
1040                 np_err(np, "%s doesn't support polling, aborting\n",
1041                        np->dev_name);
1042                 err = -ENOTSUPP;
1043                 goto out;
1044         }
1045
1046         if (!ndev->npinfo) {
1047                 npinfo = kmalloc(sizeof(*npinfo), gfp);
1048                 if (!npinfo) {
1049                         err = -ENOMEM;
1050                         goto out;
1051                 }
1052
1053                 npinfo->rx_flags = 0;
1054                 INIT_LIST_HEAD(&npinfo->rx_np);
1055
1056                 spin_lock_init(&npinfo->rx_lock);
1057                 sema_init(&npinfo->dev_lock, 1);
1058                 skb_queue_head_init(&npinfo->neigh_tx);
1059                 skb_queue_head_init(&npinfo->txq);
1060                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
1061
1062                 atomic_set(&npinfo->refcnt, 1);
1063
1064                 ops = np->dev->netdev_ops;
1065                 if (ops->ndo_netpoll_setup) {
1066                         err = ops->ndo_netpoll_setup(ndev, npinfo, gfp);
1067                         if (err)
1068                                 goto free_npinfo;
1069                 }
1070         } else {
1071                 npinfo = rtnl_dereference(ndev->npinfo);
1072                 atomic_inc(&npinfo->refcnt);
1073         }
1074
1075         npinfo->netpoll = np;
1076
1077         if (np->rx_skb_hook) {
1078                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1079                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
1080                 list_add_tail(&np->rx, &npinfo->rx_np);
1081                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1082         }
1083
1084         /* last thing to do is link it to the net device structure */
1085         rcu_assign_pointer(ndev->npinfo, npinfo);
1086
1087         return 0;
1088
1089 free_npinfo:
1090         kfree(npinfo);
1091 out:
1092         return err;
1093 }
1094 EXPORT_SYMBOL_GPL(__netpoll_setup);
1095
1096 int netpoll_setup(struct netpoll *np)
1097 {
1098         struct net_device *ndev = NULL;
1099         struct in_device *in_dev;
1100         int err;
1101
1102         rtnl_lock();
1103         if (np->dev_name) {
1104                 struct net *net = current->nsproxy->net_ns;
1105                 ndev = __dev_get_by_name(net, np->dev_name);
1106         }
1107         if (!ndev) {
1108                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
1109                 err = -ENODEV;
1110                 goto unlock;
1111         }
1112         dev_hold(ndev);
1113
1114         if (netdev_master_upper_dev_get(ndev)) {
1115                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
1116                 err = -EBUSY;
1117                 goto put;
1118         }
1119
1120         if (!netif_running(ndev)) {
1121                 unsigned long atmost, atleast;
1122
1123                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
1124
1125                 err = dev_open(ndev);
1126
1127                 if (err) {
1128                         np_err(np, "failed to open %s\n", ndev->name);
1129                         goto put;
1130                 }
1131
1132                 rtnl_unlock();
1133                 atleast = jiffies + HZ/10;
1134                 atmost = jiffies + carrier_timeout * HZ;
1135                 while (!netif_carrier_ok(ndev)) {
1136                         if (time_after(jiffies, atmost)) {
1137                                 np_notice(np, "timeout waiting for carrier\n");
1138                                 break;
1139                         }
1140                         msleep(1);
1141                 }
1142
1143                 /* If carrier appears to come up instantly, we don't
1144                  * trust it and pause so that we don't pump all our
1145                  * queued console messages into the bitbucket.
1146                  */
1147
1148                 if (time_before(jiffies, atleast)) {
1149                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
1150                         msleep(4000);
1151                 }
1152                 rtnl_lock();
1153         }
1154
1155         if (!np->local_ip.ip) {
1156                 if (!np->ipv6) {
1157                         in_dev = __in_dev_get_rtnl(ndev);
1158
1159                         if (!in_dev || !in_dev->ifa_list) {
1160                                 np_err(np, "no IP address for %s, aborting\n",
1161                                        np->dev_name);
1162                                 err = -EDESTADDRREQ;
1163                                 goto put;
1164                         }
1165
1166                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
1167                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
1168                 } else {
1169 #if IS_ENABLED(CONFIG_IPV6)
1170                         struct inet6_dev *idev;
1171
1172                         err = -EDESTADDRREQ;
1173                         idev = __in6_dev_get(ndev);
1174                         if (idev) {
1175                                 struct inet6_ifaddr *ifp;
1176
1177                                 read_lock_bh(&idev->lock);
1178                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
1179                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
1180                                                 continue;
1181                                         np->local_ip.in6 = ifp->addr;
1182                                         err = 0;
1183                                         break;
1184                                 }
1185                                 read_unlock_bh(&idev->lock);
1186                         }
1187                         if (err) {
1188                                 np_err(np, "no IPv6 address for %s, aborting\n",
1189                                        np->dev_name);
1190                                 goto put;
1191                         } else
1192                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
1193 #else
1194                         np_err(np, "IPv6 is not supported %s, aborting\n",
1195                                np->dev_name);
1196                         err = -EINVAL;
1197                         goto put;
1198 #endif
1199                 }
1200         }
1201
1202         /* fill up the skb queue */
1203         refill_skbs();
1204
1205         err = __netpoll_setup(np, ndev, GFP_KERNEL);
1206         if (err)
1207                 goto put;
1208
1209         rtnl_unlock();
1210         return 0;
1211
1212 put:
1213         dev_put(ndev);
1214 unlock:
1215         rtnl_unlock();
1216         return err;
1217 }
1218 EXPORT_SYMBOL(netpoll_setup);
1219
1220 static int __init netpoll_init(void)
1221 {
1222         skb_queue_head_init(&skb_pool);
1223         return 0;
1224 }
1225 core_initcall(netpoll_init);
1226
1227 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
1228 {
1229         struct netpoll_info *npinfo =
1230                         container_of(rcu_head, struct netpoll_info, rcu);
1231
1232         skb_queue_purge(&npinfo->neigh_tx);
1233         skb_queue_purge(&npinfo->txq);
1234
1235         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
1236         cancel_delayed_work(&npinfo->tx_work);
1237
1238         /* clean after last, unfinished work */
1239         __skb_queue_purge(&npinfo->txq);
1240         /* now cancel it again */
1241         cancel_delayed_work(&npinfo->tx_work);
1242         kfree(npinfo);
1243 }
1244
1245 void __netpoll_cleanup(struct netpoll *np)
1246 {
1247         struct netpoll_info *npinfo;
1248         unsigned long flags;
1249
1250         /* rtnl_dereference would be preferable here but
1251          * rcu_cleanup_netpoll path can put us in here safely without
1252          * holding the rtnl, so plain rcu_dereference it is
1253          */
1254         npinfo = rtnl_dereference(np->dev->npinfo);
1255         if (!npinfo)
1256                 return;
1257
1258         if (!list_empty(&npinfo->rx_np)) {
1259                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1260                 list_del(&np->rx);
1261                 if (list_empty(&npinfo->rx_np))
1262                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
1263                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1264         }
1265
1266         synchronize_srcu(&netpoll_srcu);
1267
1268         if (atomic_dec_and_test(&npinfo->refcnt)) {
1269                 const struct net_device_ops *ops;
1270
1271                 ops = np->dev->netdev_ops;
1272                 if (ops->ndo_netpoll_cleanup)
1273                         ops->ndo_netpoll_cleanup(np->dev);
1274
1275                 rcu_assign_pointer(np->dev->npinfo, NULL);
1276                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
1277         }
1278 }
1279 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
1280
1281 static void netpoll_async_cleanup(struct work_struct *work)
1282 {
1283         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
1284
1285         rtnl_lock();
1286         __netpoll_cleanup(np);
1287         rtnl_unlock();
1288         kfree(np);
1289 }
1290
1291 void __netpoll_free_async(struct netpoll *np)
1292 {
1293         schedule_work(&np->cleanup_work);
1294 }
1295 EXPORT_SYMBOL_GPL(__netpoll_free_async);
1296
1297 void netpoll_cleanup(struct netpoll *np)
1298 {
1299         rtnl_lock();
1300         if (!np->dev)
1301                 goto out;
1302         __netpoll_cleanup(np);
1303         dev_put(np->dev);
1304         np->dev = NULL;
1305 out:
1306         rtnl_unlock();
1307 }
1308 EXPORT_SYMBOL(netpoll_cleanup);
1309
1310 int netpoll_trap(void)
1311 {
1312         return atomic_read(&trapped);
1313 }
1314 EXPORT_SYMBOL(netpoll_trap);
1315
1316 void netpoll_set_trap(int trap)
1317 {
1318         if (trap)
1319                 atomic_inc(&trapped);
1320         else
1321                 atomic_dec(&trapped);
1322 }
1323 EXPORT_SYMBOL(netpoll_set_trap);