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         int status = NETDEV_TX_OK;
  76         netdev_features_t features;
  77
  78         features = netif_skb_features(skb);
  79
  80         if (skb_vlan_tag_present(skb) &&
  81             !vlan_hw_offload_capable(features, skb->vlan_proto)) {
  82                 skb = __vlan_hwaccel_push_inside(skb);
  83                 if (unlikely(!skb)) {
  84                         /* This is actually a packet drop, but we
  85                          * don't want the code that calls this
  86                          * function to try and operate on a NULL skb.
  87                          */
  88                         goto out;
  89                 }
  90         }
  91
  92         status = netdev_start_xmit(skb, dev, txq, false);
  93
  94 out:
  95         return status;
  96 }
  97
  98 static void queue_process(struct work_struct *work)
  99 {
 100         struct netpoll_info *npinfo =
 101                 container_of(work, struct netpoll_info, tx_work.work);
 102         struct sk_buff *skb;
 103         unsigned long flags;
 104
 105         while ((skb = skb_dequeue(&npinfo->txq))) {
 106                 struct net_device *dev = skb->dev;
 107                 struct netdev_queue *txq;
 108
 109                 if (!netif_device_present(dev) || !netif_running(dev)) {
 110                         kfree_skb(skb);
 111                         continue;
 112                 }
 113
 114                 txq = skb_get_tx_queue(dev, skb);
 115
 116                 local_irq_save(flags);
 117                 HARD_TX_LOCK(dev, txq, smp_processor_id());
 118                 if (netif_xmit_frozen_or_stopped(txq) ||
 119                     netpoll_start_xmit(skb, dev, txq) != NETDEV_TX_OK) {
 120                         skb_queue_head(&npinfo->txq, skb);
 121                         HARD_TX_UNLOCK(dev, txq);
 122                         local_irq_restore(flags);
 123
 124                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 125                         return;
 126                 }
 127                 HARD_TX_UNLOCK(dev, txq);
 128                 local_irq_restore(flags);
 129         }
 130 }
 131
 132 /*
 133  * Check whether delayed processing was scheduled for our NIC. If so,
 134  * we attempt to grab the poll lock and use ->poll() to pump the card.
 135  * If this fails, either we've recursed in ->poll() or it's already
 136  * running on another CPU.
 137  *
 138  * Note: we don't mask interrupts with this lock because we're using
 139  * trylock here and interrupts are already disabled in the softirq
 140  * case. Further, we test the poll_owner to avoid recursion on UP
 141  * systems where the lock doesn't exist.
 142  */
 143 static void poll_one_napi(struct napi_struct *napi)
 144 {
 145         int work = 0;
 146
 147         /* net_rx_action's ->poll() invocations and our's are
 148          * synchronized by this test which is only made while
 149          * holding the napi->poll_lock.
 150          */
 151         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 152                 return;
 153
 154         /* If we set this bit but see that it has already been set,
 155          * that indicates that napi has been disabled and we need
 156          * to abort this operation
 157          */
 158         if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
 159                 return;
 160
 161         /* We explicilty pass the polling call a budget of 0 to
 162          * indicate that we are clearing the Tx path only.
 163          */
 164         work = napi->poll(napi, 0);
 165         WARN_ONCE(work, "%pF exceeded budget in poll\n", napi->poll);
 166         trace_napi_poll(napi);
 167
 168         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 169 }
 170
 171 static void poll_napi(struct net_device *dev)
 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                         poll_one_napi(napi);
 179                         spin_unlock(&napi->poll_lock);
 180                 }
 181         }
 182 }
 183
 184 static void netpoll_poll_dev(struct net_device *dev)
 185 {
 186         const struct net_device_ops *ops;
 187         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 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);
 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         WARN_ON_ONCE(!irqs_disabled());
 389
 390         udp_len = len + sizeof(*udph);
 391         if (np->ipv6)
 392                 ip_len = udp_len + sizeof(*ip6h);
 393         else
 394                 ip_len = udp_len + sizeof(*iph);
 395
 396         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 397
 398         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 399                        total_len - len);
 400         if (!skb)
 401                 return;
 402
 403         skb_copy_to_linear_data(skb, msg, len);
 404         skb_put(skb, len);
 405
 406         skb_push(skb, sizeof(*udph));
 407         skb_reset_transport_header(skb);
 408         udph = udp_hdr(skb);
 409         udph->source = htons(np->local_port);
 410         udph->dest = htons(np->remote_port);
 411         udph->len = htons(udp_len);
 412
 413         if (np->ipv6) {
 414                 udph->check = 0;
 415                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 416                                               &np->remote_ip.in6,
 417                                               udp_len, IPPROTO_UDP,
 418                                               csum_partial(udph, udp_len, 0));
 419                 if (udph->check == 0)
 420                         udph->check = CSUM_MANGLED_0;
 421
 422                 skb_push(skb, sizeof(*ip6h));
 423                 skb_reset_network_header(skb);
 424                 ip6h = ipv6_hdr(skb);
 425
 426                 /* ip6h->version = 6; ip6h->priority = 0; */
 427                 put_unaligned(0x60, (unsigned char *)ip6h);
 428                 ip6h->flow_lbl[0] = 0;
 429                 ip6h->flow_lbl[1] = 0;
 430                 ip6h->flow_lbl[2] = 0;
 431
 432                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 433                 ip6h->nexthdr = IPPROTO_UDP;
 434                 ip6h->hop_limit = 32;
 435                 ip6h->saddr = np->local_ip.in6;
 436                 ip6h->daddr = np->remote_ip.in6;
 437
 438                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 439                 skb_reset_mac_header(skb);
 440                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 441         } else {
 442                 udph->check = 0;
 443                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 444                                                 np->remote_ip.ip,
 445                                                 udp_len, IPPROTO_UDP,
 446                                                 csum_partial(udph, udp_len, 0));
 447                 if (udph->check == 0)
 448                         udph->check = CSUM_MANGLED_0;
 449
 450                 skb_push(skb, sizeof(*iph));
 451                 skb_reset_network_header(skb);
 452                 iph = ip_hdr(skb);
 453
 454                 /* iph->version = 4; iph->ihl = 5; */
 455                 put_unaligned(0x45, (unsigned char *)iph);
 456                 iph->tos      = 0;
 457                 put_unaligned(htons(ip_len), &(iph->tot_len));
 458                 iph->id       = htons(atomic_inc_return(&ip_ident));
 459                 iph->frag_off = 0;
 460                 iph->ttl      = 64;
 461                 iph->protocol = IPPROTO_UDP;
 462                 iph->check    = 0;
 463                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 464                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 465                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 466
 467                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 468                 skb_reset_mac_header(skb);
 469                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 470         }
 471
 472         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 473         ether_addr_copy(eth->h_dest, np->remote_mac);
 474
 475         skb->dev = np->dev;
 476
 477         netpoll_send_skb(np, skb);
 478 }
 479 EXPORT_SYMBOL(netpoll_send_udp);
 480
 481 void netpoll_print_options(struct netpoll *np)
 482 {
 483         np_info(np, "local port %d\n", np->local_port);
 484         if (np->ipv6)
 485                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 486         else
 487                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 488         np_info(np, "interface '%s'\n", np->dev_name);
 489         np_info(np, "remote port %d\n", np->remote_port);
 490         if (np->ipv6)
 491                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 492         else
 493                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 494         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 495 }
 496 EXPORT_SYMBOL(netpoll_print_options);
 497
 498 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 499 {
 500         const char *end;
 501
 502         if (!strchr(str, ':') &&
 503             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 504                 if (!*end)
 505                         return 0;
 506         }
 507         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 508 #if IS_ENABLED(CONFIG_IPV6)
 509                 if (!*end)
 510                         return 1;
 511 #else
 512                 return -1;
 513 #endif
 514         }
 515         return -1;
 516 }
 517
 518 int netpoll_parse_options(struct netpoll *np, char *opt)
 519 {
 520         char *cur=opt, *delim;
 521         int ipv6;
 522         bool ipversion_set = false;
 523
 524         if (*cur != '@') {
 525                 if ((delim = strchr(cur, '@')) == NULL)
 526                         goto parse_failed;
 527                 *delim = 0;
 528                 if (kstrtou16(cur, 10, &np->local_port))
 529                         goto parse_failed;
 530                 cur = delim;
 531         }
 532         cur++;
 533
 534         if (*cur != '/') {
 535                 ipversion_set = true;
 536                 if ((delim = strchr(cur, '/')) == NULL)
 537                         goto parse_failed;
 538                 *delim = 0;
 539                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 540                 if (ipv6 < 0)
 541                         goto parse_failed;
 542                 else
 543                         np->ipv6 = (bool)ipv6;
 544                 cur = delim;
 545         }
 546         cur++;
 547
 548         if (*cur != ',') {
 549                 /* parse out dev name */
 550                 if ((delim = strchr(cur, ',')) == NULL)
 551                         goto parse_failed;
 552                 *delim = 0;
 553                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 554                 cur = delim;
 555         }
 556         cur++;
 557
 558         if (*cur != '@') {
 559                 /* dst port */
 560                 if ((delim = strchr(cur, '@')) == NULL)
 561                         goto parse_failed;
 562                 *delim = 0;
 563                 if (*cur == ' ' || *cur == '\t')
 564                         np_info(np, "warning: whitespace is not allowed\n");
 565                 if (kstrtou16(cur, 10, &np->remote_port))
 566                         goto parse_failed;
 567                 cur = delim;
 568         }
 569         cur++;
 570
 571         /* dst ip */
 572         if ((delim = strchr(cur, '/')) == NULL)
 573                 goto parse_failed;
 574         *delim = 0;
 575         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 576         if (ipv6 < 0)
 577                 goto parse_failed;
 578         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 579                 goto parse_failed;
 580         else
 581                 np->ipv6 = (bool)ipv6;
 582         cur = delim + 1;
 583
 584         if (*cur != 0) {
 585                 /* MAC address */
 586                 if (!mac_pton(cur, np->remote_mac))
 587                         goto parse_failed;
 588         }
 589
 590         netpoll_print_options(np);
 591
 592         return 0;
 593
 594  parse_failed:
 595         np_info(np, "couldn't parse config at '%s'!\n", cur);
 596         return -1;
 597 }
 598 EXPORT_SYMBOL(netpoll_parse_options);
 599
 600 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 601 {
 602         struct netpoll_info *npinfo;
 603         const struct net_device_ops *ops;
 604         int err;
 605
 606         np->dev = ndev;
 607         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 608         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
 609
 610         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 611             !ndev->netdev_ops->ndo_poll_controller) {
 612                 np_err(np, "%s doesn't support polling, aborting\n",
 613                        np->dev_name);
 614                 err = -ENOTSUPP;
 615                 goto out;
 616         }
 617
 618         if (!ndev->npinfo) {
 619                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 620                 if (!npinfo) {
 621                         err = -ENOMEM;
 622                         goto out;
 623                 }
 624
 625                 sema_init(&npinfo->dev_lock, 1);
 626                 skb_queue_head_init(&npinfo->txq);
 627                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 628
 629                 atomic_set(&npinfo->refcnt, 1);
 630
 631                 ops = np->dev->netdev_ops;
 632                 if (ops->ndo_netpoll_setup) {
 633                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 634                         if (err)
 635                                 goto free_npinfo;
 636                 }
 637         } else {
 638                 npinfo = rtnl_dereference(ndev->npinfo);
 639                 atomic_inc(&npinfo->refcnt);
 640         }
 641
 642         npinfo->netpoll = np;
 643
 644         /* last thing to do is link it to the net device structure */
 645         rcu_assign_pointer(ndev->npinfo, npinfo);
 646
 647         return 0;
 648
 649 free_npinfo:
 650         kfree(npinfo);
 651 out:
 652         return err;
 653 }
 654 EXPORT_SYMBOL_GPL(__netpoll_setup);
 655
 656 int netpoll_setup(struct netpoll *np)
 657 {
 658         struct net_device *ndev = NULL;
 659         struct in_device *in_dev;
 660         int err;
 661
 662         rtnl_lock();
 663         if (np->dev_name) {
 664                 struct net *net = current->nsproxy->net_ns;
 665                 ndev = __dev_get_by_name(net, np->dev_name);
 666         }
 667         if (!ndev) {
 668                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 669                 err = -ENODEV;
 670                 goto unlock;
 671         }
 672         dev_hold(ndev);
 673
 674         if (netdev_master_upper_dev_get(ndev)) {
 675                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 676                 err = -EBUSY;
 677                 goto put;
 678         }
 679
 680         if (!netif_running(ndev)) {
 681                 unsigned long atmost, atleast;
 682
 683                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 684
 685                 err = dev_open(ndev);
 686
 687                 if (err) {
 688                         np_err(np, "failed to open %s\n", ndev->name);
 689                         goto put;
 690                 }
 691
 692                 rtnl_unlock();
 693                 atleast = jiffies + HZ/10;
 694                 atmost = jiffies + carrier_timeout * HZ;
 695                 while (!netif_carrier_ok(ndev)) {
 696                         if (time_after(jiffies, atmost)) {
 697                                 np_notice(np, "timeout waiting for carrier\n");
 698                                 break;
 699                         }
 700                         msleep(1);
 701                 }
 702
 703                 /* If carrier appears to come up instantly, we don't
 704                  * trust it and pause so that we don't pump all our
 705                  * queued console messages into the bitbucket.
 706                  */
 707
 708                 if (time_before(jiffies, atleast)) {
 709                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 710                         msleep(4000);
 711                 }
 712                 rtnl_lock();
 713         }
 714
 715         if (!np->local_ip.ip) {
 716                 if (!np->ipv6) {
 717                         in_dev = __in_dev_get_rtnl(ndev);
 718
 719                         if (!in_dev || !in_dev->ifa_list) {
 720                                 np_err(np, "no IP address for %s, aborting\n",
 721                                        np->dev_name);
 722                                 err = -EDESTADDRREQ;
 723                                 goto put;
 724                         }
 725
 726                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
 727                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 728                 } else {
 729 #if IS_ENABLED(CONFIG_IPV6)
 730                         struct inet6_dev *idev;
 731
 732                         err = -EDESTADDRREQ;
 733                         idev = __in6_dev_get(ndev);
 734                         if (idev) {
 735                                 struct inet6_ifaddr *ifp;
 736
 737                                 read_lock_bh(&idev->lock);
 738                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 739                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
 740                                                 continue;
 741                                         np->local_ip.in6 = ifp->addr;
 742                                         err = 0;
 743                                         break;
 744                                 }
 745                                 read_unlock_bh(&idev->lock);
 746                         }
 747                         if (err) {
 748                                 np_err(np, "no IPv6 address for %s, aborting\n",
 749                                        np->dev_name);
 750                                 goto put;
 751                         } else
 752                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 753 #else
 754                         np_err(np, "IPv6 is not supported %s, aborting\n",
 755                                np->dev_name);
 756                         err = -EINVAL;
 757                         goto put;
 758 #endif
 759                 }
 760         }
 761
 762         /* fill up the skb queue */
 763         refill_skbs();
 764
 765         err = __netpoll_setup(np, ndev);
 766         if (err)
 767                 goto put;
 768
 769         rtnl_unlock();
 770         return 0;
 771
 772 put:
 773         dev_put(ndev);
 774 unlock:
 775         rtnl_unlock();
 776         return err;
 777 }
 778 EXPORT_SYMBOL(netpoll_setup);
 779
 780 static int __init netpoll_init(void)
 781 {
 782         skb_queue_head_init(&skb_pool);
 783         return 0;
 784 }
 785 core_initcall(netpoll_init);
 786
 787 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 788 {
 789         struct netpoll_info *npinfo =
 790                         container_of(rcu_head, struct netpoll_info, rcu);
 791
 792         skb_queue_purge(&npinfo->txq);
 793
 794         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 795         cancel_delayed_work(&npinfo->tx_work);
 796
 797         /* clean after last, unfinished work */
 798         __skb_queue_purge(&npinfo->txq);
 799         /* now cancel it again */
 800         cancel_delayed_work(&npinfo->tx_work);
 801         kfree(npinfo);
 802 }
 803
 804 void __netpoll_cleanup(struct netpoll *np)
 805 {
 806         struct netpoll_info *npinfo;
 807
 808         /* rtnl_dereference would be preferable here but
 809          * rcu_cleanup_netpoll path can put us in here safely without
 810          * holding the rtnl, so plain rcu_dereference it is
 811          */
 812         npinfo = rtnl_dereference(np->dev->npinfo);
 813         if (!npinfo)
 814                 return;
 815
 816         synchronize_srcu(&netpoll_srcu);
 817
 818         if (atomic_dec_and_test(&npinfo->refcnt)) {
 819                 const struct net_device_ops *ops;
 820
 821                 ops = np->dev->netdev_ops;
 822                 if (ops->ndo_netpoll_cleanup)
 823                         ops->ndo_netpoll_cleanup(np->dev);
 824
 825                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 826                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
 827         } else
 828                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 829 }
 830 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 831
 832 static void netpoll_async_cleanup(struct work_struct *work)
 833 {
 834         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
 835
 836         rtnl_lock();
 837         __netpoll_cleanup(np);
 838         rtnl_unlock();
 839         kfree(np);
 840 }
 841
 842 void __netpoll_free_async(struct netpoll *np)
 843 {
 844         schedule_work(&np->cleanup_work);
 845 }
 846 EXPORT_SYMBOL_GPL(__netpoll_free_async);
 847
 848 void netpoll_cleanup(struct netpoll *np)
 849 {
 850         rtnl_lock();
 851         if (!np->dev)
 852                 goto out;
 853         __netpoll_cleanup(np);
 854         dev_put(np->dev);
 855         np->dev = NULL;
 856 out:
 857         rtnl_unlock();
 858 }
 859 EXPORT_SYMBOL(netpoll_cleanup);