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 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo);
  52 #endif
  53
  54 DEFINE_STATIC_SRCU(netpoll_srcu);
  55
  56 #define USEC_PER_POLL   50
  57
  58 #define MAX_SKB_SIZE                                                    \
  59         (sizeof(struct ethhdr) +                                        \
  60          sizeof(struct iphdr) +                                         \
  61          sizeof(struct udphdr) +                                        \
  62          MAX_UDP_CHUNK)
  63
  64 static void zap_completion_queue(void);
  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 #ifdef CONFIG_NETPOLL_TRAP
 113 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 114                             unsigned short ulen, __be32 saddr, __be32 daddr)
 115 {
 116         __wsum psum;
 117
 118         if (uh->check == 0 || skb_csum_unnecessary(skb))
 119                 return 0;
 120
 121         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 122
 123         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 124             !csum_fold(csum_add(psum, skb->csum)))
 125                 return 0;
 126
 127         skb->csum = psum;
 128
 129         return __skb_checksum_complete(skb);
 130 }
 131 #endif /* CONFIG_NETPOLL_TRAP */
 132
 133 /*
 134  * Check whether delayed processing was scheduled for our NIC. If so,
 135  * we attempt to grab the poll lock and use ->poll() to pump the card.
 136  * If this fails, either we've recursed in ->poll() or it's already
 137  * running on another CPU.
 138  *
 139  * Note: we don't mask interrupts with this lock because we're using
 140  * trylock here and interrupts are already disabled in the softirq
 141  * case. Further, we test the poll_owner to avoid recursion on UP
 142  * systems where the lock doesn't exist.
 143  *
 144  * In cases where there is bi-directional communications, reading only
 145  * one message at a time can lead to packets being dropped by the
 146  * network adapter, forcing superfluous retries and possibly timeouts.
 147  * Thus, we set our budget to greater than 1.
 148  */
 149 static int poll_one_napi(struct napi_struct *napi, int budget)
 150 {
 151         int work;
 152
 153         /* net_rx_action's ->poll() invocations and our's are
 154          * synchronized by this test which is only made while
 155          * holding the napi->poll_lock.
 156          */
 157         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 158                 return budget;
 159
 160         set_bit(NAPI_STATE_NPSVC, &napi->state);
 161
 162         work = napi->poll(napi, budget);
 163         WARN_ONCE(work > budget, "%pF exceeded budget in poll\n", napi->poll);
 164         trace_napi_poll(napi);
 165
 166         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 167
 168         return budget - work;
 169 }
 170
 171 static void poll_napi(struct net_device *dev, int budget)
 172 {
 173         struct napi_struct *napi;
 174
 175         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 176                 if (napi->poll_owner != smp_processor_id() &&
 177                     spin_trylock(&napi->poll_lock)) {
 178                         budget = poll_one_napi(napi, budget);
 179                         spin_unlock(&napi->poll_lock);
 180                 }
 181         }
 182 }
 183
 184 #ifdef CONFIG_NETPOLL_TRAP
 185 static void service_neigh_queue(struct net_device *dev,
 186                                 struct netpoll_info *npi)
 187 {
 188         struct sk_buff *skb;
 189         if (dev->flags & IFF_SLAVE) {
 190                 struct net_device *bond_dev;
 191                 struct netpoll_info *bond_ni;
 192
 193                 bond_dev = netdev_master_upper_dev_get_rcu(dev);
 194                 bond_ni = rcu_dereference_bh(bond_dev->npinfo);
 195                 while ((skb = skb_dequeue(&npi->neigh_tx))) {
 196                         skb->dev = bond_dev;
 197                         skb_queue_tail(&bond_ni->neigh_tx, skb);
 198                 }
 199         }
 200         while ((skb = skb_dequeue(&npi->neigh_tx)))
 201                 netpoll_neigh_reply(skb, npi);
 202 }
 203 #else /* !CONFIG_NETPOLL_TRAP */
 204 static inline void service_neigh_queue(struct net_device *dev,
 205                                 struct netpoll_info *npi)
 206 {
 207 }
 208 #endif /* CONFIG_NETPOLL_TRAP */
 209
 210 static void netpoll_poll_dev(struct net_device *dev)
 211 {
 212         const struct net_device_ops *ops;
 213         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 214         bool rx_processing = netpoll_rx_processing(ni);
 215         int budget = rx_processing? 16 : 0;
 216
 217         /* Don't do any rx activity if the dev_lock mutex is held
 218          * the dev_open/close paths use this to block netpoll activity
 219          * while changing device state
 220          */
 221         if (down_trylock(&ni->dev_lock))
 222                 return;
 223
 224         if (!netif_running(dev)) {
 225                 up(&ni->dev_lock);
 226                 return;
 227         }
 228
 229         if (rx_processing)
 230                 netpoll_set_trap(1);
 231
 232         ops = dev->netdev_ops;
 233         if (!ops->ndo_poll_controller) {
 234                 up(&ni->dev_lock);
 235                 return;
 236         }
 237
 238         /* Process pending work on NIC */
 239         ops->ndo_poll_controller(dev);
 240
 241         poll_napi(dev, budget);
 242
 243         if (rx_processing)
 244                 netpoll_set_trap(0);
 245
 246         up(&ni->dev_lock);
 247
 248         service_neigh_queue(dev, ni);
 249
 250         zap_completion_queue();
 251 }
 252
 253 void netpoll_rx_disable(struct net_device *dev)
 254 {
 255         struct netpoll_info *ni;
 256         int idx;
 257         might_sleep();
 258         idx = srcu_read_lock(&netpoll_srcu);
 259         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 260         if (ni)
 261                 down(&ni->dev_lock);
 262         srcu_read_unlock(&netpoll_srcu, idx);
 263 }
 264 EXPORT_SYMBOL(netpoll_rx_disable);
 265
 266 void netpoll_rx_enable(struct net_device *dev)
 267 {
 268         struct netpoll_info *ni;
 269         rcu_read_lock();
 270         ni = rcu_dereference(dev->npinfo);
 271         if (ni)
 272                 up(&ni->dev_lock);
 273         rcu_read_unlock();
 274 }
 275 EXPORT_SYMBOL(netpoll_rx_enable);
 276
 277 static void refill_skbs(void)
 278 {
 279         struct sk_buff *skb;
 280         unsigned long flags;
 281
 282         spin_lock_irqsave(&skb_pool.lock, flags);
 283         while (skb_pool.qlen < MAX_SKBS) {
 284                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 285                 if (!skb)
 286                         break;
 287
 288                 __skb_queue_tail(&skb_pool, skb);
 289         }
 290         spin_unlock_irqrestore(&skb_pool.lock, flags);
 291 }
 292
 293 static void zap_completion_queue(void)
 294 {
 295         unsigned long flags;
 296         struct softnet_data *sd = &get_cpu_var(softnet_data);
 297
 298         if (sd->completion_queue) {
 299                 struct sk_buff *clist;
 300
 301                 local_irq_save(flags);
 302                 clist = sd->completion_queue;
 303                 sd->completion_queue = NULL;
 304                 local_irq_restore(flags);
 305
 306                 while (clist != NULL) {
 307                         struct sk_buff *skb = clist;
 308                         clist = clist->next;
 309                         if (skb->destructor) {
 310                                 atomic_inc(&skb->users);
 311                                 dev_kfree_skb_any(skb); /* put this one back */
 312                         } else {
 313                                 __kfree_skb(skb);
 314                         }
 315                 }
 316         }
 317
 318         put_cpu_var(softnet_data);
 319 }
 320
 321 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 322 {
 323         int count = 0;
 324         struct sk_buff *skb;
 325
 326         zap_completion_queue();
 327         refill_skbs();
 328 repeat:
 329
 330         skb = alloc_skb(len, GFP_ATOMIC);
 331         if (!skb)
 332                 skb = skb_dequeue(&skb_pool);
 333
 334         if (!skb) {
 335                 if (++count < 10) {
 336                         netpoll_poll_dev(np->dev);
 337                         goto repeat;
 338                 }
 339                 return NULL;
 340         }
 341
 342         atomic_set(&skb->users, 1);
 343         skb_reserve(skb, reserve);
 344         return skb;
 345 }
 346
 347 static int netpoll_owner_active(struct net_device *dev)
 348 {
 349         struct napi_struct *napi;
 350
 351         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 352                 if (napi->poll_owner == smp_processor_id())
 353                         return 1;
 354         }
 355         return 0;
 356 }
 357
 358 /* call with IRQ disabled */
 359 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 360                              struct net_device *dev)
 361 {
 362         int status = NETDEV_TX_BUSY;
 363         unsigned long tries;
 364         const struct net_device_ops *ops = dev->netdev_ops;
 365         /* It is up to the caller to keep npinfo alive. */
 366         struct netpoll_info *npinfo;
 367
 368         WARN_ON_ONCE(!irqs_disabled());
 369
 370         npinfo = rcu_dereference_bh(np->dev->npinfo);
 371         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 372                 __kfree_skb(skb);
 373                 return;
 374         }
 375
 376         /* don't get messages out of order, and no recursion */
 377         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 378                 struct netdev_queue *txq;
 379
 380                 txq = netdev_pick_tx(dev, skb, NULL);
 381
 382                 /* try until next clock tick */
 383                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 384                      tries > 0; --tries) {
 385                         if (__netif_tx_trylock(txq)) {
 386                                 if (!netif_xmit_stopped(txq)) {
 387                                         if (vlan_tx_tag_present(skb) &&
 388                                             !vlan_hw_offload_capable(netif_skb_features(skb),
 389                                                                      skb->vlan_proto)) {
 390                                                 skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
 391                                                 if (unlikely(!skb)) {
 392                                                         /* This is actually a packet drop, but we
 393                                                          * don't want the code at the end of this
 394                                                          * function to try and re-queue a NULL skb.
 395                                                          */
 396                                                         status = NETDEV_TX_OK;
 397                                                         goto unlock_txq;
 398                                                 }
 399                                                 skb->vlan_tci = 0;
 400                                         }
 401
 402                                         status = ops->ndo_start_xmit(skb, dev);
 403                                         if (status == NETDEV_TX_OK)
 404                                                 txq_trans_update(txq);
 405                                 }
 406                         unlock_txq:
 407                                 __netif_tx_unlock(txq);
 408
 409                                 if (status == NETDEV_TX_OK)
 410                                         break;
 411
 412                         }
 413
 414                         /* tickle device maybe there is some cleanup */
 415                         netpoll_poll_dev(np->dev);
 416
 417                         udelay(USEC_PER_POLL);
 418                 }
 419
 420                 WARN_ONCE(!irqs_disabled(),
 421                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 422                         dev->name, ops->ndo_start_xmit);
 423
 424         }
 425
 426         if (status != NETDEV_TX_OK) {
 427                 skb_queue_tail(&npinfo->txq, skb);
 428                 schedule_delayed_work(&npinfo->tx_work,0);
 429         }
 430 }
 431 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 432
 433 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 434 {
 435         int total_len, ip_len, udp_len;
 436         struct sk_buff *skb;
 437         struct udphdr *udph;
 438         struct iphdr *iph;
 439         struct ethhdr *eth;
 440         static atomic_t ip_ident;
 441         struct ipv6hdr *ip6h;
 442
 443         udp_len = len + sizeof(*udph);
 444         if (np->ipv6)
 445                 ip_len = udp_len + sizeof(*ip6h);
 446         else
 447                 ip_len = udp_len + sizeof(*iph);
 448
 449         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 450
 451         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 452                        total_len - len);
 453         if (!skb)
 454                 return;
 455
 456         skb_copy_to_linear_data(skb, msg, len);
 457         skb_put(skb, len);
 458
 459         skb_push(skb, sizeof(*udph));
 460         skb_reset_transport_header(skb);
 461         udph = udp_hdr(skb);
 462         udph->source = htons(np->local_port);
 463         udph->dest = htons(np->remote_port);
 464         udph->len = htons(udp_len);
 465
 466         if (np->ipv6) {
 467                 udph->check = 0;
 468                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 469                                               &np->remote_ip.in6,
 470                                               udp_len, IPPROTO_UDP,
 471                                               csum_partial(udph, udp_len, 0));
 472                 if (udph->check == 0)
 473                         udph->check = CSUM_MANGLED_0;
 474
 475                 skb_push(skb, sizeof(*ip6h));
 476                 skb_reset_network_header(skb);
 477                 ip6h = ipv6_hdr(skb);
 478
 479                 /* ip6h->version = 6; ip6h->priority = 0; */
 480                 put_unaligned(0x60, (unsigned char *)ip6h);
 481                 ip6h->flow_lbl[0] = 0;
 482                 ip6h->flow_lbl[1] = 0;
 483                 ip6h->flow_lbl[2] = 0;
 484
 485                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 486                 ip6h->nexthdr = IPPROTO_UDP;
 487                 ip6h->hop_limit = 32;
 488                 ip6h->saddr = np->local_ip.in6;
 489                 ip6h->daddr = np->remote_ip.in6;
 490
 491                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 492                 skb_reset_mac_header(skb);
 493                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 494         } else {
 495                 udph->check = 0;
 496                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 497                                                 np->remote_ip.ip,
 498                                                 udp_len, IPPROTO_UDP,
 499                                                 csum_partial(udph, udp_len, 0));
 500                 if (udph->check == 0)
 501                         udph->check = CSUM_MANGLED_0;
 502
 503                 skb_push(skb, sizeof(*iph));
 504                 skb_reset_network_header(skb);
 505                 iph = ip_hdr(skb);
 506
 507                 /* iph->version = 4; iph->ihl = 5; */
 508                 put_unaligned(0x45, (unsigned char *)iph);
 509                 iph->tos      = 0;
 510                 put_unaligned(htons(ip_len), &(iph->tot_len));
 511                 iph->id       = htons(atomic_inc_return(&ip_ident));
 512                 iph->frag_off = 0;
 513                 iph->ttl      = 64;
 514                 iph->protocol = IPPROTO_UDP;
 515                 iph->check    = 0;
 516                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 517                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 518                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 519
 520                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 521                 skb_reset_mac_header(skb);
 522                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 523         }
 524
 525         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 526         ether_addr_copy(eth->h_dest, np->remote_mac);
 527
 528         skb->dev = np->dev;
 529
 530         netpoll_send_skb(np, skb);
 531 }
 532 EXPORT_SYMBOL(netpoll_send_udp);
 533
 534 #ifdef CONFIG_NETPOLL_TRAP
 535 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo)
 536 {
 537         int size, type = ARPOP_REPLY;
 538         __be32 sip, tip;
 539         unsigned char *sha;
 540         struct sk_buff *send_skb;
 541         struct netpoll *np, *tmp;
 542         unsigned long flags;
 543         int hlen, tlen;
 544         int hits = 0, proto;
 545
 546         if (!netpoll_rx_processing(npinfo))
 547                 return;
 548
 549         /* Before checking the packet, we do some early
 550            inspection whether this is interesting at all */
 551         spin_lock_irqsave(&npinfo->rx_lock, flags);
 552         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 553                 if (np->dev == skb->dev)
 554                         hits++;
 555         }
 556         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 557
 558         /* No netpoll struct is using this dev */
 559         if (!hits)
 560                 return;
 561
 562         proto = ntohs(eth_hdr(skb)->h_proto);
 563         if (proto == ETH_P_ARP) {
 564                 struct arphdr *arp;
 565                 unsigned char *arp_ptr;
 566                 /* No arp on this interface */
 567                 if (skb->dev->flags & IFF_NOARP)
 568                         return;
 569
 570                 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 571                         return;
 572
 573                 skb_reset_network_header(skb);
 574                 skb_reset_transport_header(skb);
 575                 arp = arp_hdr(skb);
 576
 577                 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 578                      arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 579                     arp->ar_pro != htons(ETH_P_IP) ||
 580                     arp->ar_op != htons(ARPOP_REQUEST))
 581                         return;
 582
 583                 arp_ptr = (unsigned char *)(arp+1);
 584                 /* save the location of the src hw addr */
 585                 sha = arp_ptr;
 586                 arp_ptr += skb->dev->addr_len;
 587                 memcpy(&sip, arp_ptr, 4);
 588                 arp_ptr += 4;
 589                 /* If we actually cared about dst hw addr,
 590                    it would get copied here */
 591                 arp_ptr += skb->dev->addr_len;
 592                 memcpy(&tip, arp_ptr, 4);
 593
 594                 /* Should we ignore arp? */
 595                 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 596                         return;
 597
 598                 size = arp_hdr_len(skb->dev);
 599
 600                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 601                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 602                         if (tip != np->local_ip.ip)
 603                                 continue;
 604
 605                         hlen = LL_RESERVED_SPACE(np->dev);
 606                         tlen = np->dev->needed_tailroom;
 607                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 608                         if (!send_skb)
 609                                 continue;
 610
 611                         skb_reset_network_header(send_skb);
 612                         arp = (struct arphdr *) skb_put(send_skb, size);
 613                         send_skb->dev = skb->dev;
 614                         send_skb->protocol = htons(ETH_P_ARP);
 615
 616                         /* Fill the device header for the ARP frame */
 617                         if (dev_hard_header(send_skb, skb->dev, ETH_P_ARP,
 618                                             sha, np->dev->dev_addr,
 619                                             send_skb->len) < 0) {
 620                                 kfree_skb(send_skb);
 621                                 continue;
 622                         }
 623
 624                         /*
 625                          * Fill out the arp protocol part.
 626                          *
 627                          * we only support ethernet device type,
 628                          * which (according to RFC 1390) should
 629                          * always equal 1 (Ethernet).
 630                          */
 631
 632                         arp->ar_hrd = htons(np->dev->type);
 633                         arp->ar_pro = htons(ETH_P_IP);
 634                         arp->ar_hln = np->dev->addr_len;
 635                         arp->ar_pln = 4;
 636                         arp->ar_op = htons(type);
 637
 638                         arp_ptr = (unsigned char *)(arp + 1);
 639                         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 640                         arp_ptr += np->dev->addr_len;
 641                         memcpy(arp_ptr, &tip, 4);
 642                         arp_ptr += 4;
 643                         memcpy(arp_ptr, sha, np->dev->addr_len);
 644                         arp_ptr += np->dev->addr_len;
 645                         memcpy(arp_ptr, &sip, 4);
 646
 647                         netpoll_send_skb(np, send_skb);
 648
 649                         /* If there are several rx_skb_hooks for the same
 650                          * address we're fine by sending a single reply
 651                          */
 652                         break;
 653                 }
 654                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 655         } else if( proto == ETH_P_IPV6) {
 656 #if IS_ENABLED(CONFIG_IPV6)
 657                 struct nd_msg *msg;
 658                 u8 *lladdr = NULL;
 659                 struct ipv6hdr *hdr;
 660                 struct icmp6hdr *icmp6h;
 661                 const struct in6_addr *saddr;
 662                 const struct in6_addr *daddr;
 663                 struct inet6_dev *in6_dev = NULL;
 664                 struct in6_addr *target;
 665
 666                 in6_dev = in6_dev_get(skb->dev);
 667                 if (!in6_dev || !in6_dev->cnf.accept_ra)
 668                         return;
 669
 670                 if (!pskb_may_pull(skb, skb->len))
 671                         return;
 672
 673                 msg = (struct nd_msg *)skb_transport_header(skb);
 674
 675                 __skb_push(skb, skb->data - skb_transport_header(skb));
 676
 677                 if (ipv6_hdr(skb)->hop_limit != 255)
 678                         return;
 679                 if (msg->icmph.icmp6_code != 0)
 680                         return;
 681                 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 682                         return;
 683
 684                 saddr = &ipv6_hdr(skb)->saddr;
 685                 daddr = &ipv6_hdr(skb)->daddr;
 686
 687                 size = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
 688
 689                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 690                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 691                         if (!ipv6_addr_equal(daddr, &np->local_ip.in6))
 692                                 continue;
 693
 694                         hlen = LL_RESERVED_SPACE(np->dev);
 695                         tlen = np->dev->needed_tailroom;
 696                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 697                         if (!send_skb)
 698                                 continue;
 699
 700                         send_skb->protocol = htons(ETH_P_IPV6);
 701                         send_skb->dev = skb->dev;
 702
 703                         skb_reset_network_header(send_skb);
 704                         hdr = (struct ipv6hdr *) skb_put(send_skb, sizeof(struct ipv6hdr));
 705                         *(__be32*)hdr = htonl(0x60000000);
 706                         hdr->payload_len = htons(size);
 707                         hdr->nexthdr = IPPROTO_ICMPV6;
 708                         hdr->hop_limit = 255;
 709                         hdr->saddr = *saddr;
 710                         hdr->daddr = *daddr;
 711
 712                         icmp6h = (struct icmp6hdr *) skb_put(send_skb, sizeof(struct icmp6hdr));
 713                         icmp6h->icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
 714                         icmp6h->icmp6_router = 0;
 715                         icmp6h->icmp6_solicited = 1;
 716
 717                         target = (struct in6_addr *) skb_put(send_skb, sizeof(struct in6_addr));
 718                         *target = msg->target;
 719                         icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, size,
 720                                                               IPPROTO_ICMPV6,
 721                                                               csum_partial(icmp6h,
 722                                                                            size, 0));
 723
 724                         if (dev_hard_header(send_skb, skb->dev, ETH_P_IPV6,
 725                                             lladdr, np->dev->dev_addr,
 726                                             send_skb->len) < 0) {
 727                                 kfree_skb(send_skb);
 728                                 continue;
 729                         }
 730
 731                         netpoll_send_skb(np, send_skb);
 732
 733                         /* If there are several rx_skb_hooks for the same
 734                          * address, we're fine by sending a single reply
 735                          */
 736                         break;
 737                 }
 738                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 739 #endif
 740         }
 741 }
 742
 743 static bool pkt_is_ns(struct sk_buff *skb)
 744 {
 745         struct nd_msg *msg;
 746         struct ipv6hdr *hdr;
 747
 748         if (skb->protocol != htons(ETH_P_ARP))
 749                 return false;
 750         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct nd_msg)))
 751                 return false;
 752
 753         msg = (struct nd_msg *)skb_transport_header(skb);
 754         __skb_push(skb, skb->data - skb_transport_header(skb));
 755         hdr = ipv6_hdr(skb);
 756
 757         if (hdr->nexthdr != IPPROTO_ICMPV6)
 758                 return false;
 759         if (hdr->hop_limit != 255)
 760                 return false;
 761         if (msg->icmph.icmp6_code != 0)
 762                 return false;
 763         if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 764                 return false;
 765
 766         return true;
 767 }
 768
 769 int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo)
 770 {
 771         int proto, len, ulen, data_len;
 772         int hits = 0, offset;
 773         const struct iphdr *iph;
 774         struct udphdr *uh;
 775         struct netpoll *np, *tmp;
 776         uint16_t source;
 777
 778         if (!netpoll_rx_processing(npinfo))
 779                 goto out;
 780
 781         if (skb->dev->type != ARPHRD_ETHER)
 782                 goto out;
 783
 784         /* check if netpoll clients need ARP */
 785         if (skb->protocol == htons(ETH_P_ARP) && netpoll_trap()) {
 786                 skb_queue_tail(&npinfo->neigh_tx, skb);
 787                 return 1;
 788         } else if (pkt_is_ns(skb) && netpoll_trap()) {
 789                 skb_queue_tail(&npinfo->neigh_tx, skb);
 790                 return 1;
 791         }
 792
 793         if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
 794                 skb = vlan_untag(skb);
 795                 if (unlikely(!skb))
 796                         goto out;
 797         }
 798
 799         proto = ntohs(eth_hdr(skb)->h_proto);
 800         if (proto != ETH_P_IP && proto != ETH_P_IPV6)
 801                 goto out;
 802         if (skb->pkt_type == PACKET_OTHERHOST)
 803                 goto out;
 804         if (skb_shared(skb))
 805                 goto out;
 806
 807         if (proto == ETH_P_IP) {
 808                 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 809                         goto out;
 810                 iph = (struct iphdr *)skb->data;
 811                 if (iph->ihl < 5 || iph->version != 4)
 812                         goto out;
 813                 if (!pskb_may_pull(skb, iph->ihl*4))
 814                         goto out;
 815                 iph = (struct iphdr *)skb->data;
 816                 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 817                         goto out;
 818
 819                 len = ntohs(iph->tot_len);
 820                 if (skb->len < len || len < iph->ihl*4)
 821                         goto out;
 822
 823                 /*
 824                  * Our transport medium may have padded the buffer out.
 825                  * Now We trim to the true length of the frame.
 826                  */
 827                 if (pskb_trim_rcsum(skb, len))
 828                         goto out;
 829
 830                 iph = (struct iphdr *)skb->data;
 831                 if (iph->protocol != IPPROTO_UDP)
 832                         goto out;
 833
 834                 len -= iph->ihl*4;
 835                 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 836                 offset = (unsigned char *)(uh + 1) - skb->data;
 837                 ulen = ntohs(uh->len);
 838                 data_len = skb->len - offset;
 839                 source = ntohs(uh->source);
 840
 841                 if (ulen != len)
 842                         goto out;
 843                 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 844                         goto out;
 845                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 846                         if (np->local_ip.ip && np->local_ip.ip != iph->daddr)
 847                                 continue;
 848                         if (np->remote_ip.ip && np->remote_ip.ip != iph->saddr)
 849                                 continue;
 850                         if (np->local_port && np->local_port != ntohs(uh->dest))
 851                                 continue;
 852
 853                         np->rx_skb_hook(np, source, skb, offset, data_len);
 854                         hits++;
 855                 }
 856         } else {
 857 #if IS_ENABLED(CONFIG_IPV6)
 858                 const struct ipv6hdr *ip6h;
 859
 860                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 861                         goto out;
 862                 ip6h = (struct ipv6hdr *)skb->data;
 863                 if (ip6h->version != 6)
 864                         goto out;
 865                 len = ntohs(ip6h->payload_len);
 866                 if (!len)
 867                         goto out;
 868                 if (len + sizeof(struct ipv6hdr) > skb->len)
 869                         goto out;
 870                 if (pskb_trim_rcsum(skb, len + sizeof(struct ipv6hdr)))
 871                         goto out;
 872                 ip6h = ipv6_hdr(skb);
 873                 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 874                         goto out;
 875                 uh = udp_hdr(skb);
 876                 offset = (unsigned char *)(uh + 1) - skb->data;
 877                 ulen = ntohs(uh->len);
 878                 data_len = skb->len - offset;
 879                 source = ntohs(uh->source);
 880                 if (ulen != skb->len)
 881                         goto out;
 882                 if (udp6_csum_init(skb, uh, IPPROTO_UDP))
 883                         goto out;
 884                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 885                         if (!ipv6_addr_equal(&np->local_ip.in6, &ip6h->daddr))
 886                                 continue;
 887                         if (!ipv6_addr_equal(&np->remote_ip.in6, &ip6h->saddr))
 888                                 continue;
 889                         if (np->local_port && np->local_port != ntohs(uh->dest))
 890                                 continue;
 891
 892                         np->rx_skb_hook(np, source, skb, offset, data_len);
 893                         hits++;
 894                 }
 895 #endif
 896         }
 897
 898         if (!hits)
 899                 goto out;
 900
 901         kfree_skb(skb);
 902         return 1;
 903
 904 out:
 905         if (netpoll_trap()) {
 906                 kfree_skb(skb);
 907                 return 1;
 908         }
 909
 910         return 0;
 911 }
 912
 913 static void netpoll_trap_setup_info(struct netpoll_info *npinfo)
 914 {
 915         INIT_LIST_HEAD(&npinfo->rx_np);
 916         spin_lock_init(&npinfo->rx_lock);
 917         skb_queue_head_init(&npinfo->neigh_tx);
 918 }
 919
 920 static void netpoll_trap_cleanup_info(struct netpoll_info *npinfo)
 921 {
 922         skb_queue_purge(&npinfo->neigh_tx);
 923 }
 924
 925 static void netpoll_trap_setup(struct netpoll *np, struct netpoll_info *npinfo)
 926 {
 927         unsigned long flags;
 928         if (np->rx_skb_hook) {
 929                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 930                 list_add_tail(&np->rx, &npinfo->rx_np);
 931                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 932         }
 933 }
 934
 935 static void netpoll_trap_cleanup(struct netpoll *np, struct netpoll_info *npinfo)
 936 {
 937         unsigned long flags;
 938         if (!list_empty(&npinfo->rx_np)) {
 939                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 940                 list_del(&np->rx);
 941                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 942         }
 943 }
 944
 945 #else /* !CONFIG_NETPOLL_TRAP */
 946 static inline void netpoll_trap_setup_info(struct netpoll_info *npinfo)
 947 {
 948 }
 949 static inline void netpoll_trap_cleanup_info(struct netpoll_info *npinfo)
 950 {
 951 }
 952 static inline
 953 void netpoll_trap_setup(struct netpoll *np, struct netpoll_info *npinfo)
 954 {
 955 }
 956 static inline
 957 void netpoll_trap_cleanup(struct netpoll *np, struct netpoll_info *npinfo)
 958 {
 959 }
 960 #endif /* CONFIG_NETPOLL_TRAP */
 961
 962 void netpoll_print_options(struct netpoll *np)
 963 {
 964         np_info(np, "local port %d\n", np->local_port);
 965         if (np->ipv6)
 966                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 967         else
 968                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 969         np_info(np, "interface '%s'\n", np->dev_name);
 970         np_info(np, "remote port %d\n", np->remote_port);
 971         if (np->ipv6)
 972                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 973         else
 974                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 975         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 976 }
 977 EXPORT_SYMBOL(netpoll_print_options);
 978
 979 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 980 {
 981         const char *end;
 982
 983         if (!strchr(str, ':') &&
 984             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 985                 if (!*end)
 986                         return 0;
 987         }
 988         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 989 #if IS_ENABLED(CONFIG_IPV6)
 990                 if (!*end)
 991                         return 1;
 992 #else
 993                 return -1;
 994 #endif
 995         }
 996         return -1;
 997 }
 998
 999 int netpoll_parse_options(struct netpoll *np, char *opt)
1000 {
1001         char *cur=opt, *delim;
1002         int ipv6;
1003         bool ipversion_set = false;
1004
1005         if (*cur != '@') {
1006                 if ((delim = strchr(cur, '@')) == NULL)
1007                         goto parse_failed;
1008                 *delim = 0;
1009                 if (kstrtou16(cur, 10, &np->local_port))
1010                         goto parse_failed;
1011                 cur = delim;
1012         }
1013         cur++;
1014
1015         if (*cur != '/') {
1016                 ipversion_set = true;
1017                 if ((delim = strchr(cur, '/')) == NULL)
1018                         goto parse_failed;
1019                 *delim = 0;
1020                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
1021                 if (ipv6 < 0)
1022                         goto parse_failed;
1023                 else
1024                         np->ipv6 = (bool)ipv6;
1025                 cur = delim;
1026         }
1027         cur++;
1028
1029         if (*cur != ',') {
1030                 /* parse out dev name */
1031                 if ((delim = strchr(cur, ',')) == NULL)
1032                         goto parse_failed;
1033                 *delim = 0;
1034                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
1035                 cur = delim;
1036         }
1037         cur++;
1038
1039         if (*cur != '@') {
1040                 /* dst port */
1041                 if ((delim = strchr(cur, '@')) == NULL)
1042                         goto parse_failed;
1043                 *delim = 0;
1044                 if (*cur == ' ' || *cur == '\t')
1045                         np_info(np, "warning: whitespace is not allowed\n");
1046                 if (kstrtou16(cur, 10, &np->remote_port))
1047                         goto parse_failed;
1048                 cur = delim;
1049         }
1050         cur++;
1051
1052         /* dst ip */
1053         if ((delim = strchr(cur, '/')) == NULL)
1054                 goto parse_failed;
1055         *delim = 0;
1056         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
1057         if (ipv6 < 0)
1058                 goto parse_failed;
1059         else if (ipversion_set && np->ipv6 != (bool)ipv6)
1060                 goto parse_failed;
1061         else
1062                 np->ipv6 = (bool)ipv6;
1063         cur = delim + 1;
1064
1065         if (*cur != 0) {
1066                 /* MAC address */
1067                 if (!mac_pton(cur, np->remote_mac))
1068                         goto parse_failed;
1069         }
1070
1071         netpoll_print_options(np);
1072
1073         return 0;
1074
1075  parse_failed:
1076         np_info(np, "couldn't parse config at '%s'!\n", cur);
1077         return -1;
1078 }
1079 EXPORT_SYMBOL(netpoll_parse_options);
1080
1081 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
1082 {
1083         struct netpoll_info *npinfo;
1084         const struct net_device_ops *ops;
1085         int err;
1086
1087         np->dev = ndev;
1088         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
1089         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
1090
1091         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
1092             !ndev->netdev_ops->ndo_poll_controller) {
1093                 np_err(np, "%s doesn't support polling, aborting\n",
1094                        np->dev_name);
1095                 err = -ENOTSUPP;
1096                 goto out;
1097         }
1098
1099         if (!ndev->npinfo) {
1100                 npinfo = kmalloc(sizeof(*npinfo), gfp);
1101                 if (!npinfo) {
1102                         err = -ENOMEM;
1103                         goto out;
1104                 }
1105
1106                 netpoll_trap_setup_info(npinfo);
1107
1108                 sema_init(&npinfo->dev_lock, 1);
1109                 skb_queue_head_init(&npinfo->txq);
1110                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
1111
1112                 atomic_set(&npinfo->refcnt, 1);
1113
1114                 ops = np->dev->netdev_ops;
1115                 if (ops->ndo_netpoll_setup) {
1116                         err = ops->ndo_netpoll_setup(ndev, npinfo, gfp);
1117                         if (err)
1118                                 goto free_npinfo;
1119                 }
1120         } else {
1121                 npinfo = rtnl_dereference(ndev->npinfo);
1122                 atomic_inc(&npinfo->refcnt);
1123         }
1124
1125         npinfo->netpoll = np;
1126
1127         netpoll_trap_setup(np, npinfo);
1128
1129         /* last thing to do is link it to the net device structure */
1130         rcu_assign_pointer(ndev->npinfo, npinfo);
1131
1132         return 0;
1133
1134 free_npinfo:
1135         kfree(npinfo);
1136 out:
1137         return err;
1138 }
1139 EXPORT_SYMBOL_GPL(__netpoll_setup);
1140
1141 int netpoll_setup(struct netpoll *np)
1142 {
1143         struct net_device *ndev = NULL;
1144         struct in_device *in_dev;
1145         int err;
1146
1147         rtnl_lock();
1148         if (np->dev_name) {
1149                 struct net *net = current->nsproxy->net_ns;
1150                 ndev = __dev_get_by_name(net, np->dev_name);
1151         }
1152         if (!ndev) {
1153                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
1154                 err = -ENODEV;
1155                 goto unlock;
1156         }
1157         dev_hold(ndev);
1158
1159         if (netdev_master_upper_dev_get(ndev)) {
1160                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
1161                 err = -EBUSY;
1162                 goto put;
1163         }
1164
1165         if (!netif_running(ndev)) {
1166                 unsigned long atmost, atleast;
1167
1168                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
1169
1170                 err = dev_open(ndev);
1171
1172                 if (err) {
1173                         np_err(np, "failed to open %s\n", ndev->name);
1174                         goto put;
1175                 }
1176
1177                 rtnl_unlock();
1178                 atleast = jiffies + HZ/10;
1179                 atmost = jiffies + carrier_timeout * HZ;
1180                 while (!netif_carrier_ok(ndev)) {
1181                         if (time_after(jiffies, atmost)) {
1182                                 np_notice(np, "timeout waiting for carrier\n");
1183                                 break;
1184                         }
1185                         msleep(1);
1186                 }
1187
1188                 /* If carrier appears to come up instantly, we don't
1189                  * trust it and pause so that we don't pump all our
1190                  * queued console messages into the bitbucket.
1191                  */
1192
1193                 if (time_before(jiffies, atleast)) {
1194                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
1195                         msleep(4000);
1196                 }
1197                 rtnl_lock();
1198         }
1199
1200         if (!np->local_ip.ip) {
1201                 if (!np->ipv6) {
1202                         in_dev = __in_dev_get_rtnl(ndev);
1203
1204                         if (!in_dev || !in_dev->ifa_list) {
1205                                 np_err(np, "no IP address for %s, aborting\n",
1206                                        np->dev_name);
1207                                 err = -EDESTADDRREQ;
1208                                 goto put;
1209                         }
1210
1211                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
1212                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
1213                 } else {
1214 #if IS_ENABLED(CONFIG_IPV6)
1215                         struct inet6_dev *idev;
1216
1217                         err = -EDESTADDRREQ;
1218                         idev = __in6_dev_get(ndev);
1219                         if (idev) {
1220                                 struct inet6_ifaddr *ifp;
1221
1222                                 read_lock_bh(&idev->lock);
1223                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
1224                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
1225                                                 continue;
1226                                         np->local_ip.in6 = ifp->addr;
1227                                         err = 0;
1228                                         break;
1229                                 }
1230                                 read_unlock_bh(&idev->lock);
1231                         }
1232                         if (err) {
1233                                 np_err(np, "no IPv6 address for %s, aborting\n",
1234                                        np->dev_name);
1235                                 goto put;
1236                         } else
1237                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
1238 #else
1239                         np_err(np, "IPv6 is not supported %s, aborting\n",
1240                                np->dev_name);
1241                         err = -EINVAL;
1242                         goto put;
1243 #endif
1244                 }
1245         }
1246
1247         /* fill up the skb queue */
1248         refill_skbs();
1249
1250         err = __netpoll_setup(np, ndev, GFP_KERNEL);
1251         if (err)
1252                 goto put;
1253
1254         rtnl_unlock();
1255         return 0;
1256
1257 put:
1258         dev_put(ndev);
1259 unlock:
1260         rtnl_unlock();
1261         return err;
1262 }
1263 EXPORT_SYMBOL(netpoll_setup);
1264
1265 static int __init netpoll_init(void)
1266 {
1267         skb_queue_head_init(&skb_pool);
1268         return 0;
1269 }
1270 core_initcall(netpoll_init);
1271
1272 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
1273 {
1274         struct netpoll_info *npinfo =
1275                         container_of(rcu_head, struct netpoll_info, rcu);
1276
1277         netpoll_trap_cleanup_info(npinfo);
1278         skb_queue_purge(&npinfo->txq);
1279
1280         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
1281         cancel_delayed_work(&npinfo->tx_work);
1282
1283         /* clean after last, unfinished work */
1284         __skb_queue_purge(&npinfo->txq);
1285         /* now cancel it again */
1286         cancel_delayed_work(&npinfo->tx_work);
1287         kfree(npinfo);
1288 }
1289
1290 void __netpoll_cleanup(struct netpoll *np)
1291 {
1292         struct netpoll_info *npinfo;
1293
1294         /* rtnl_dereference would be preferable here but
1295          * rcu_cleanup_netpoll path can put us in here safely without
1296          * holding the rtnl, so plain rcu_dereference it is
1297          */
1298         npinfo = rtnl_dereference(np->dev->npinfo);
1299         if (!npinfo)
1300                 return;
1301
1302         netpoll_trap_cleanup(np, npinfo);
1303
1304         synchronize_srcu(&netpoll_srcu);
1305
1306         if (atomic_dec_and_test(&npinfo->refcnt)) {
1307                 const struct net_device_ops *ops;
1308
1309                 ops = np->dev->netdev_ops;
1310                 if (ops->ndo_netpoll_cleanup)
1311                         ops->ndo_netpoll_cleanup(np->dev);
1312
1313                 rcu_assign_pointer(np->dev->npinfo, NULL);
1314                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
1315         }
1316 }
1317 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
1318
1319 static void netpoll_async_cleanup(struct work_struct *work)
1320 {
1321         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
1322
1323         rtnl_lock();
1324         __netpoll_cleanup(np);
1325         rtnl_unlock();
1326         kfree(np);
1327 }
1328
1329 void __netpoll_free_async(struct netpoll *np)
1330 {
1331         schedule_work(&np->cleanup_work);
1332 }
1333 EXPORT_SYMBOL_GPL(__netpoll_free_async);
1334
1335 void netpoll_cleanup(struct netpoll *np)
1336 {
1337         rtnl_lock();
1338         if (!np->dev)
1339                 goto out;
1340         __netpoll_cleanup(np);
1341         dev_put(np->dev);
1342         np->dev = NULL;
1343 out:
1344         rtnl_unlock();
1345 }
1346 EXPORT_SYMBOL(netpoll_cleanup);
1347
1348 #ifdef CONFIG_NETPOLL_TRAP
1349 int netpoll_trap(void)
1350 {
1351         return atomic_read(&trapped);
1352 }
1353 EXPORT_SYMBOL(netpoll_trap);
1354
1355 void netpoll_set_trap(int trap)
1356 {
1357         if (trap)
1358                 atomic_inc(&trapped);
1359         else
1360                 atomic_dec(&trapped);
1361 }
1362 EXPORT_SYMBOL(netpoll_set_trap);
1363 #endif /* CONFIG_NETPOLL_TRAP */