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