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 DEFINE_STATIC_SRCU(netpoll_srcu);
  50
  51 #define USEC_PER_POLL   50
  52
  53 #define MAX_SKB_SIZE                                                    \
  54         (sizeof(struct ethhdr) +                                        \
  55          sizeof(struct iphdr) +                                         \
  56          sizeof(struct udphdr) +                                        \
  57          MAX_UDP_CHUNK)
  58
  59 static void zap_completion_queue(void);
  60 static void netpoll_async_cleanup(struct work_struct *work);
  61
  62 static unsigned int carrier_timeout = 4;
  63 module_param(carrier_timeout, uint, 0644);
  64
  65 #define np_info(np, fmt, ...)                           \
  66         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  67 #define np_err(np, fmt, ...)                            \
  68         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  69 #define np_notice(np, fmt, ...)                         \
  70         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  71
  72 static int netpoll_start_xmit(struct sk_buff *skb, struct net_device *dev,
  73                               struct netdev_queue *txq)
  74 {
  75         const struct net_device_ops *ops = dev->netdev_ops;
  76         int status = NETDEV_TX_OK;
  77         netdev_features_t features;
  78
  79         features = netif_skb_features(skb);
  80
  81         if (vlan_tx_tag_present(skb) &&
  82             !vlan_hw_offload_capable(features, skb->vlan_proto)) {
  83                 skb = __vlan_put_tag(skb, skb->vlan_proto,
  84                                      vlan_tx_tag_get(skb));
  85                 if (unlikely(!skb)) {
  86                         /* This is actually a packet drop, but we
  87                          * don't want the code that calls this
  88                          * function to try and operate on a NULL skb.
  89                          */
  90                         goto out;
  91                 }
  92                 skb->vlan_tci = 0;
  93         }
  94
  95         status = ops->ndo_start_xmit(skb, dev);
  96         if (status == NETDEV_TX_OK)
  97                 txq_trans_update(txq);
  98
  99 out:
 100         return status;
 101 }
 102
 103 static void queue_process(struct work_struct *work)
 104 {
 105         struct netpoll_info *npinfo =
 106                 container_of(work, struct netpoll_info, tx_work.work);
 107         struct sk_buff *skb;
 108         unsigned long flags;
 109
 110         while ((skb = skb_dequeue(&npinfo->txq))) {
 111                 struct net_device *dev = skb->dev;
 112                 struct netdev_queue *txq;
 113
 114                 if (!netif_device_present(dev) || !netif_running(dev)) {
 115                         kfree_skb(skb);
 116                         continue;
 117                 }
 118
 119                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 120
 121                 local_irq_save(flags);
 122                 HARD_TX_LOCK(dev, txq, smp_processor_id());
 123                 if (netif_xmit_frozen_or_stopped(txq) ||
 124                     netpoll_start_xmit(skb, dev, txq) != NETDEV_TX_OK) {
 125                         skb_queue_head(&npinfo->txq, skb);
 126                         HARD_TX_UNLOCK(dev, txq);
 127                         local_irq_restore(flags);
 128
 129                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 130                         return;
 131                 }
 132                 HARD_TX_UNLOCK(dev, txq);
 133                 local_irq_restore(flags);
 134         }
 135 }
 136
 137 /*
 138  * Check whether delayed processing was scheduled for our NIC. If so,
 139  * we attempt to grab the poll lock and use ->poll() to pump the card.
 140  * If this fails, either we've recursed in ->poll() or it's already
 141  * running on another CPU.
 142  *
 143  * Note: we don't mask interrupts with this lock because we're using
 144  * trylock here and interrupts are already disabled in the softirq
 145  * case. Further, we test the poll_owner to avoid recursion on UP
 146  * systems where the lock doesn't exist.
 147  */
 148 static int poll_one_napi(struct napi_struct *napi, int budget)
 149 {
 150         int work;
 151
 152         /* net_rx_action's ->poll() invocations and our's are
 153          * synchronized by this test which is only made while
 154          * holding the napi->poll_lock.
 155          */
 156         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 157                 return budget;
 158
 159         set_bit(NAPI_STATE_NPSVC, &napi->state);
 160
 161         work = napi->poll(napi, budget);
 162         WARN_ONCE(work > budget, "%pF exceeded budget in poll\n", napi->poll);
 163         trace_napi_poll(napi);
 164
 165         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 166
 167         return budget - work;
 168 }
 169
 170 static void poll_napi(struct net_device *dev, int budget)
 171 {
 172         struct napi_struct *napi;
 173
 174         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 175                 if (napi->poll_owner != smp_processor_id() &&
 176                     spin_trylock(&napi->poll_lock)) {
 177                         budget = poll_one_napi(napi, budget);
 178                         spin_unlock(&napi->poll_lock);
 179                 }
 180         }
 181 }
 182
 183 static void netpoll_poll_dev(struct net_device *dev)
 184 {
 185         const struct net_device_ops *ops;
 186         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 187         int budget = 0;
 188
 189         /* Don't do any rx activity if the dev_lock mutex is held
 190          * the dev_open/close paths use this to block netpoll activity
 191          * while changing device state
 192          */
 193         if (down_trylock(&ni->dev_lock))
 194                 return;
 195
 196         if (!netif_running(dev)) {
 197                 up(&ni->dev_lock);
 198                 return;
 199         }
 200
 201         ops = dev->netdev_ops;
 202         if (!ops->ndo_poll_controller) {
 203                 up(&ni->dev_lock);
 204                 return;
 205         }
 206
 207         /* Process pending work on NIC */
 208         ops->ndo_poll_controller(dev);
 209
 210         poll_napi(dev, budget);
 211
 212         up(&ni->dev_lock);
 213
 214         zap_completion_queue();
 215 }
 216
 217 void netpoll_poll_disable(struct net_device *dev)
 218 {
 219         struct netpoll_info *ni;
 220         int idx;
 221         might_sleep();
 222         idx = srcu_read_lock(&netpoll_srcu);
 223         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 224         if (ni)
 225                 down(&ni->dev_lock);
 226         srcu_read_unlock(&netpoll_srcu, idx);
 227 }
 228 EXPORT_SYMBOL(netpoll_poll_disable);
 229
 230 void netpoll_poll_enable(struct net_device *dev)
 231 {
 232         struct netpoll_info *ni;
 233         rcu_read_lock();
 234         ni = rcu_dereference(dev->npinfo);
 235         if (ni)
 236                 up(&ni->dev_lock);
 237         rcu_read_unlock();
 238 }
 239 EXPORT_SYMBOL(netpoll_poll_enable);
 240
 241 static void refill_skbs(void)
 242 {
 243         struct sk_buff *skb;
 244         unsigned long flags;
 245
 246         spin_lock_irqsave(&skb_pool.lock, flags);
 247         while (skb_pool.qlen < MAX_SKBS) {
 248                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 249                 if (!skb)
 250                         break;
 251
 252                 __skb_queue_tail(&skb_pool, skb);
 253         }
 254         spin_unlock_irqrestore(&skb_pool.lock, flags);
 255 }
 256
 257 static void zap_completion_queue(void)
 258 {
 259         unsigned long flags;
 260         struct softnet_data *sd = &get_cpu_var(softnet_data);
 261
 262         if (sd->completion_queue) {
 263                 struct sk_buff *clist;
 264
 265                 local_irq_save(flags);
 266                 clist = sd->completion_queue;
 267                 sd->completion_queue = NULL;
 268                 local_irq_restore(flags);
 269
 270                 while (clist != NULL) {
 271                         struct sk_buff *skb = clist;
 272                         clist = clist->next;
 273                         if (!skb_irq_freeable(skb)) {
 274                                 atomic_inc(&skb->users);
 275                                 dev_kfree_skb_any(skb); /* put this one back */
 276                         } else {
 277                                 __kfree_skb(skb);
 278                         }
 279                 }
 280         }
 281
 282         put_cpu_var(softnet_data);
 283 }
 284
 285 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 286 {
 287         int count = 0;
 288         struct sk_buff *skb;
 289
 290         zap_completion_queue();
 291         refill_skbs();
 292 repeat:
 293
 294         skb = alloc_skb(len, GFP_ATOMIC);
 295         if (!skb)
 296                 skb = skb_dequeue(&skb_pool);
 297
 298         if (!skb) {
 299                 if (++count < 10) {
 300                         netpoll_poll_dev(np->dev);
 301                         goto repeat;
 302                 }
 303                 return NULL;
 304         }
 305
 306         atomic_set(&skb->users, 1);
 307         skb_reserve(skb, reserve);
 308         return skb;
 309 }
 310
 311 static int netpoll_owner_active(struct net_device *dev)
 312 {
 313         struct napi_struct *napi;
 314
 315         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 316                 if (napi->poll_owner == smp_processor_id())
 317                         return 1;
 318         }
 319         return 0;
 320 }
 321
 322 /* call with IRQ disabled */
 323 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 324                              struct net_device *dev)
 325 {
 326         int status = NETDEV_TX_BUSY;
 327         unsigned long tries;
 328         /* It is up to the caller to keep npinfo alive. */
 329         struct netpoll_info *npinfo;
 330
 331         WARN_ON_ONCE(!irqs_disabled());
 332
 333         npinfo = rcu_dereference_bh(np->dev->npinfo);
 334         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 335                 dev_kfree_skb_irq(skb);
 336                 return;
 337         }
 338
 339         /* don't get messages out of order, and no recursion */
 340         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 341                 struct netdev_queue *txq;
 342
 343                 txq = netdev_pick_tx(dev, skb, NULL);
 344
 345                 /* try until next clock tick */
 346                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 347                      tries > 0; --tries) {
 348                         if (HARD_TX_TRYLOCK(dev, txq)) {
 349                                 if (!netif_xmit_stopped(txq))
 350                                         status = netpoll_start_xmit(skb, dev, txq);
 351
 352                                 HARD_TX_UNLOCK(dev, txq);
 353
 354                                 if (status == NETDEV_TX_OK)
 355                                         break;
 356
 357                         }
 358
 359                         /* tickle device maybe there is some cleanup */
 360                         netpoll_poll_dev(np->dev);
 361
 362                         udelay(USEC_PER_POLL);
 363                 }
 364
 365                 WARN_ONCE(!irqs_disabled(),
 366                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 367                         dev->name, dev->netdev_ops->ndo_start_xmit);
 368
 369         }
 370
 371         if (status != NETDEV_TX_OK) {
 372                 skb_queue_tail(&npinfo->txq, skb);
 373                 schedule_delayed_work(&npinfo->tx_work,0);
 374         }
 375 }
 376 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 377
 378 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 379 {
 380         int total_len, ip_len, udp_len;
 381         struct sk_buff *skb;
 382         struct udphdr *udph;
 383         struct iphdr *iph;
 384         struct ethhdr *eth;
 385         static atomic_t ip_ident;
 386         struct ipv6hdr *ip6h;
 387
 388         udp_len = len + sizeof(*udph);
 389         if (np->ipv6)
 390                 ip_len = udp_len + sizeof(*ip6h);
 391         else
 392                 ip_len = udp_len + sizeof(*iph);
 393
 394         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 395
 396         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 397                        total_len - len);
 398         if (!skb)
 399                 return;
 400
 401         skb_copy_to_linear_data(skb, msg, len);
 402         skb_put(skb, len);
 403
 404         skb_push(skb, sizeof(*udph));
 405         skb_reset_transport_header(skb);
 406         udph = udp_hdr(skb);
 407         udph->source = htons(np->local_port);
 408         udph->dest = htons(np->remote_port);
 409         udph->len = htons(udp_len);
 410
 411         if (np->ipv6) {
 412                 udph->check = 0;
 413                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 414                                               &np->remote_ip.in6,
 415                                               udp_len, IPPROTO_UDP,
 416                                               csum_partial(udph, udp_len, 0));
 417                 if (udph->check == 0)
 418                         udph->check = CSUM_MANGLED_0;
 419
 420                 skb_push(skb, sizeof(*ip6h));
 421                 skb_reset_network_header(skb);
 422                 ip6h = ipv6_hdr(skb);
 423
 424                 /* ip6h->version = 6; ip6h->priority = 0; */
 425                 put_unaligned(0x60, (unsigned char *)ip6h);
 426                 ip6h->flow_lbl[0] = 0;
 427                 ip6h->flow_lbl[1] = 0;
 428                 ip6h->flow_lbl[2] = 0;
 429
 430                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 431                 ip6h->nexthdr = IPPROTO_UDP;
 432                 ip6h->hop_limit = 32;
 433                 ip6h->saddr = np->local_ip.in6;
 434                 ip6h->daddr = np->remote_ip.in6;
 435
 436                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 437                 skb_reset_mac_header(skb);
 438                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 439         } else {
 440                 udph->check = 0;
 441                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 442                                                 np->remote_ip.ip,
 443                                                 udp_len, IPPROTO_UDP,
 444                                                 csum_partial(udph, udp_len, 0));
 445                 if (udph->check == 0)
 446                         udph->check = CSUM_MANGLED_0;
 447
 448                 skb_push(skb, sizeof(*iph));
 449                 skb_reset_network_header(skb);
 450                 iph = ip_hdr(skb);
 451
 452                 /* iph->version = 4; iph->ihl = 5; */
 453                 put_unaligned(0x45, (unsigned char *)iph);
 454                 iph->tos      = 0;
 455                 put_unaligned(htons(ip_len), &(iph->tot_len));
 456                 iph->id       = htons(atomic_inc_return(&ip_ident));
 457                 iph->frag_off = 0;
 458                 iph->ttl      = 64;
 459                 iph->protocol = IPPROTO_UDP;
 460                 iph->check    = 0;
 461                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 462                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 463                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 464
 465                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 466                 skb_reset_mac_header(skb);
 467                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 468         }
 469
 470         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 471         ether_addr_copy(eth->h_dest, np->remote_mac);
 472
 473         skb->dev = np->dev;
 474
 475         netpoll_send_skb(np, skb);
 476 }
 477 EXPORT_SYMBOL(netpoll_send_udp);
 478
 479 void netpoll_print_options(struct netpoll *np)
 480 {
 481         np_info(np, "local port %d\n", np->local_port);
 482         if (np->ipv6)
 483                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 484         else
 485                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 486         np_info(np, "interface '%s'\n", np->dev_name);
 487         np_info(np, "remote port %d\n", np->remote_port);
 488         if (np->ipv6)
 489                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 490         else
 491                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 492         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 493 }
 494 EXPORT_SYMBOL(netpoll_print_options);
 495
 496 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 497 {
 498         const char *end;
 499
 500         if (!strchr(str, ':') &&
 501             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 502                 if (!*end)
 503                         return 0;
 504         }
 505         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 506 #if IS_ENABLED(CONFIG_IPV6)
 507                 if (!*end)
 508                         return 1;
 509 #else
 510                 return -1;
 511 #endif
 512         }
 513         return -1;
 514 }
 515
 516 int netpoll_parse_options(struct netpoll *np, char *opt)
 517 {
 518         char *cur=opt, *delim;
 519         int ipv6;
 520         bool ipversion_set = false;
 521
 522         if (*cur != '@') {
 523                 if ((delim = strchr(cur, '@')) == NULL)
 524                         goto parse_failed;
 525                 *delim = 0;
 526                 if (kstrtou16(cur, 10, &np->local_port))
 527                         goto parse_failed;
 528                 cur = delim;
 529         }
 530         cur++;
 531
 532         if (*cur != '/') {
 533                 ipversion_set = true;
 534                 if ((delim = strchr(cur, '/')) == NULL)
 535                         goto parse_failed;
 536                 *delim = 0;
 537                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 538                 if (ipv6 < 0)
 539                         goto parse_failed;
 540                 else
 541                         np->ipv6 = (bool)ipv6;
 542                 cur = delim;
 543         }
 544         cur++;
 545
 546         if (*cur != ',') {
 547                 /* parse out dev name */
 548                 if ((delim = strchr(cur, ',')) == NULL)
 549                         goto parse_failed;
 550                 *delim = 0;
 551                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 552                 cur = delim;
 553         }
 554         cur++;
 555
 556         if (*cur != '@') {
 557                 /* dst port */
 558                 if ((delim = strchr(cur, '@')) == NULL)
 559                         goto parse_failed;
 560                 *delim = 0;
 561                 if (*cur == ' ' || *cur == '\t')
 562                         np_info(np, "warning: whitespace is not allowed\n");
 563                 if (kstrtou16(cur, 10, &np->remote_port))
 564                         goto parse_failed;
 565                 cur = delim;
 566         }
 567         cur++;
 568
 569         /* dst ip */
 570         if ((delim = strchr(cur, '/')) == NULL)
 571                 goto parse_failed;
 572         *delim = 0;
 573         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 574         if (ipv6 < 0)
 575                 goto parse_failed;
 576         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 577                 goto parse_failed;
 578         else
 579                 np->ipv6 = (bool)ipv6;
 580         cur = delim + 1;
 581
 582         if (*cur != 0) {
 583                 /* MAC address */
 584                 if (!mac_pton(cur, np->remote_mac))
 585                         goto parse_failed;
 586         }
 587
 588         netpoll_print_options(np);
 589
 590         return 0;
 591
 592  parse_failed:
 593         np_info(np, "couldn't parse config at '%s'!\n", cur);
 594         return -1;
 595 }
 596 EXPORT_SYMBOL(netpoll_parse_options);
 597
 598 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 599 {
 600         struct netpoll_info *npinfo;
 601         const struct net_device_ops *ops;
 602         int err;
 603
 604         np->dev = ndev;
 605         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 606         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
 607
 608         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 609             !ndev->netdev_ops->ndo_poll_controller) {
 610                 np_err(np, "%s doesn't support polling, aborting\n",
 611                        np->dev_name);
 612                 err = -ENOTSUPP;
 613                 goto out;
 614         }
 615
 616         if (!ndev->npinfo) {
 617                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 618                 if (!npinfo) {
 619                         err = -ENOMEM;
 620                         goto out;
 621                 }
 622
 623                 sema_init(&npinfo->dev_lock, 1);
 624                 skb_queue_head_init(&npinfo->txq);
 625                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 626
 627                 atomic_set(&npinfo->refcnt, 1);
 628
 629                 ops = np->dev->netdev_ops;
 630                 if (ops->ndo_netpoll_setup) {
 631                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 632                         if (err)
 633                                 goto free_npinfo;
 634                 }
 635         } else {
 636                 npinfo = rtnl_dereference(ndev->npinfo);
 637                 atomic_inc(&npinfo->refcnt);
 638         }
 639
 640         npinfo->netpoll = np;
 641
 642         /* last thing to do is link it to the net device structure */
 643         rcu_assign_pointer(ndev->npinfo, npinfo);
 644
 645         return 0;
 646
 647 free_npinfo:
 648         kfree(npinfo);
 649 out:
 650         return err;
 651 }
 652 EXPORT_SYMBOL_GPL(__netpoll_setup);
 653
 654 int netpoll_setup(struct netpoll *np)
 655 {
 656         struct net_device *ndev = NULL;
 657         struct in_device *in_dev;
 658         int err;
 659
 660         rtnl_lock();
 661         if (np->dev_name) {
 662                 struct net *net = current->nsproxy->net_ns;
 663                 ndev = __dev_get_by_name(net, np->dev_name);
 664         }
 665         if (!ndev) {
 666                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 667                 err = -ENODEV;
 668                 goto unlock;
 669         }
 670         dev_hold(ndev);
 671
 672         if (netdev_master_upper_dev_get(ndev)) {
 673                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 674                 err = -EBUSY;
 675                 goto put;
 676         }
 677
 678         if (!netif_running(ndev)) {
 679                 unsigned long atmost, atleast;
 680
 681                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 682
 683                 err = dev_open(ndev);
 684
 685                 if (err) {
 686                         np_err(np, "failed to open %s\n", ndev->name);
 687                         goto put;
 688                 }
 689
 690                 rtnl_unlock();
 691                 atleast = jiffies + HZ/10;
 692                 atmost = jiffies + carrier_timeout * HZ;
 693                 while (!netif_carrier_ok(ndev)) {
 694                         if (time_after(jiffies, atmost)) {
 695                                 np_notice(np, "timeout waiting for carrier\n");
 696                                 break;
 697                         }
 698                         msleep(1);
 699                 }
 700
 701                 /* If carrier appears to come up instantly, we don't
 702                  * trust it and pause so that we don't pump all our
 703                  * queued console messages into the bitbucket.
 704                  */
 705
 706                 if (time_before(jiffies, atleast)) {
 707                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 708                         msleep(4000);
 709                 }
 710                 rtnl_lock();
 711         }
 712
 713         if (!np->local_ip.ip) {
 714                 if (!np->ipv6) {
 715                         in_dev = __in_dev_get_rtnl(ndev);
 716
 717                         if (!in_dev || !in_dev->ifa_list) {
 718                                 np_err(np, "no IP address for %s, aborting\n",
 719                                        np->dev_name);
 720                                 err = -EDESTADDRREQ;
 721                                 goto put;
 722                         }
 723
 724                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
 725                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 726                 } else {
 727 #if IS_ENABLED(CONFIG_IPV6)
 728                         struct inet6_dev *idev;
 729
 730                         err = -EDESTADDRREQ;
 731                         idev = __in6_dev_get(ndev);
 732                         if (idev) {
 733                                 struct inet6_ifaddr *ifp;
 734
 735                                 read_lock_bh(&idev->lock);
 736                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 737                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
 738                                                 continue;
 739                                         np->local_ip.in6 = ifp->addr;
 740                                         err = 0;
 741                                         break;
 742                                 }
 743                                 read_unlock_bh(&idev->lock);
 744                         }
 745                         if (err) {
 746                                 np_err(np, "no IPv6 address for %s, aborting\n",
 747                                        np->dev_name);
 748                                 goto put;
 749                         } else
 750                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 751 #else
 752                         np_err(np, "IPv6 is not supported %s, aborting\n",
 753                                np->dev_name);
 754                         err = -EINVAL;
 755                         goto put;
 756 #endif
 757                 }
 758         }
 759
 760         /* fill up the skb queue */
 761         refill_skbs();
 762
 763         err = __netpoll_setup(np, ndev);
 764         if (err)
 765                 goto put;
 766
 767         rtnl_unlock();
 768         return 0;
 769
 770 put:
 771         dev_put(ndev);
 772 unlock:
 773         rtnl_unlock();
 774         return err;
 775 }
 776 EXPORT_SYMBOL(netpoll_setup);
 777
 778 static int __init netpoll_init(void)
 779 {
 780         skb_queue_head_init(&skb_pool);
 781         return 0;
 782 }
 783 core_initcall(netpoll_init);
 784
 785 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 786 {
 787         struct netpoll_info *npinfo =
 788                         container_of(rcu_head, struct netpoll_info, rcu);
 789
 790         skb_queue_purge(&npinfo->txq);
 791
 792         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 793         cancel_delayed_work(&npinfo->tx_work);
 794
 795         /* clean after last, unfinished work */
 796         __skb_queue_purge(&npinfo->txq);
 797         /* now cancel it again */
 798         cancel_delayed_work(&npinfo->tx_work);
 799         kfree(npinfo);
 800 }
 801
 802 void __netpoll_cleanup(struct netpoll *np)
 803 {
 804         struct netpoll_info *npinfo;
 805
 806         /* rtnl_dereference would be preferable here but
 807          * rcu_cleanup_netpoll path can put us in here safely without
 808          * holding the rtnl, so plain rcu_dereference it is
 809          */
 810         npinfo = rtnl_dereference(np->dev->npinfo);
 811         if (!npinfo)
 812                 return;
 813
 814         synchronize_srcu(&netpoll_srcu);
 815
 816         if (atomic_dec_and_test(&npinfo->refcnt)) {
 817                 const struct net_device_ops *ops;
 818
 819                 ops = np->dev->netdev_ops;
 820                 if (ops->ndo_netpoll_cleanup)
 821                         ops->ndo_netpoll_cleanup(np->dev);
 822
 823                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 824                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
 825         }
 826 }
 827 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 828
 829 static void netpoll_async_cleanup(struct work_struct *work)
 830 {
 831         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
 832
 833         rtnl_lock();
 834         __netpoll_cleanup(np);
 835         rtnl_unlock();
 836         kfree(np);
 837 }
 838
 839 void __netpoll_free_async(struct netpoll *np)
 840 {
 841         schedule_work(&np->cleanup_work);
 842 }
 843 EXPORT_SYMBOL_GPL(__netpoll_free_async);
 844
 845 void netpoll_cleanup(struct netpoll *np)
 846 {
 847         rtnl_lock();
 848         if (!np->dev)
 849                 goto out;
 850         __netpoll_cleanup(np);
 851         dev_put(np->dev);
 852         np->dev = NULL;
 853 out:
 854         rtnl_unlock();
 855 }
 856 EXPORT_SYMBOL(netpoll_cleanup);