net/core/netpoll.c

   1 /*
   2  * Common framework for low-level network console, dump, and debugger code
   3  *
   4  * Sep 8 2003  Matt Mackall <[email protected]>
   5  *
   6  * based on the netconsole code from:
   7  *
   8  * Copyright (C) 2001  Ingo Molnar <[email protected]>
   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 int poll_one_napi(struct napi_struct *napi, int budget)
 144 {
 145         int work;
 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 budget;
 153
 154         set_bit(NAPI_STATE_NPSVC, &napi->state);
 155
 156         work = napi->poll(napi, budget);
 157         WARN_ONCE(work > budget, "%pF exceeded budget in poll\n", napi->poll);
 158         trace_napi_poll(napi);
 159
 160         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 161
 162         return budget - work;
 163 }
 164
 165 static void poll_napi(struct net_device *dev, int budget)
 166 {
 167         struct napi_struct *napi;
 168
 169         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 170                 if (napi->poll_owner != smp_processor_id() &&
 171                     spin_trylock(&napi->poll_lock)) {
 172                         budget = poll_one_napi(napi, budget);
 173                         spin_unlock(&napi->poll_lock);
 174                 }
 175         }
 176 }
 177
 178 static void netpoll_poll_dev(struct net_device *dev)
 179 {
 180         const struct net_device_ops *ops;
 181         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 182         int budget = 0;
 183
 184         /* Don't do any rx activity if the dev_lock mutex is held
 185          * the dev_open/close paths use this to block netpoll activity
 186          * while changing device state
 187          */
 188         if (down_trylock(&ni->dev_lock))
 189                 return;
 190
 191         if (!netif_running(dev)) {
 192                 up(&ni->dev_lock);
 193                 return;
 194         }
 195
 196         ops = dev->netdev_ops;
 197         if (!ops->ndo_poll_controller) {
 198                 up(&ni->dev_lock);
 199                 return;
 200         }
 201
 202         /* Process pending work on NIC */
 203         ops->ndo_poll_controller(dev);
 204
 205         poll_napi(dev, budget);
 206
 207         up(&ni->dev_lock);
 208
 209         zap_completion_queue();
 210 }
 211
 212 void netpoll_poll_disable(struct net_device *dev)
 213 {
 214         struct netpoll_info *ni;
 215         int idx;
 216         might_sleep();
 217         idx = srcu_read_lock(&netpoll_srcu);
 218         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 219         if (ni)
 220                 down(&ni->dev_lock);
 221         srcu_read_unlock(&netpoll_srcu, idx);
 222 }
 223 EXPORT_SYMBOL(netpoll_poll_disable);
 224
 225 void netpoll_poll_enable(struct net_device *dev)
 226 {
 227         struct netpoll_info *ni;
 228         rcu_read_lock();
 229         ni = rcu_dereference(dev->npinfo);
 230         if (ni)
 231                 up(&ni->dev_lock);
 232         rcu_read_unlock();
 233 }
 234 EXPORT_SYMBOL(netpoll_poll_enable);
 235
 236 static void refill_skbs(void)
 237 {
 238         struct sk_buff *skb;
 239         unsigned long flags;
 240
 241         spin_lock_irqsave(&skb_pool.lock, flags);
 242         while (skb_pool.qlen < MAX_SKBS) {
 243                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 244                 if (!skb)
 245                         break;
 246
 247                 __skb_queue_tail(&skb_pool, skb);
 248         }
 249         spin_unlock_irqrestore(&skb_pool.lock, flags);
 250 }
 251
 252 static void zap_completion_queue(void)
 253 {
 254         unsigned long flags;
 255         struct softnet_data *sd = &get_cpu_var(softnet_data);
 256
 257         if (sd->completion_queue) {
 258                 struct sk_buff *clist;
 259
 260                 local_irq_save(flags);
 261                 clist = sd->completion_queue;
 262                 sd->completion_queue = NULL;
 263                 local_irq_restore(flags);
 264
 265                 while (clist != NULL) {
 266                         struct sk_buff *skb = clist;
 267                         clist = clist->next;
 268                         if (!skb_irq_freeable(skb)) {
 269                                 atomic_inc(&skb->users);
 270                                 dev_kfree_skb_any(skb); /* put this one back */
 271                         } else {
 272                                 __kfree_skb(skb);
 273                         }
 274                 }
 275         }
 276
 277         put_cpu_var(softnet_data);
 278 }
 279
 280 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 281 {
 282         int count = 0;
 283         struct sk_buff *skb;
 284
 285         zap_completion_queue();
 286         refill_skbs();
 287 repeat:
 288
 289         skb = alloc_skb(len, GFP_ATOMIC);
 290         if (!skb)
 291                 skb = skb_dequeue(&skb_pool);
 292
 293         if (!skb) {
 294                 if (++count < 10) {
 295                         netpoll_poll_dev(np->dev);
 296                         goto repeat;
 297                 }
 298                 return NULL;
 299         }
 300
 301         atomic_set(&skb->users, 1);
 302         skb_reserve(skb, reserve);
 303         return skb;
 304 }
 305
 306 static int netpoll_owner_active(struct net_device *dev)
 307 {
 308         struct napi_struct *napi;
 309
 310         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 311                 if (napi->poll_owner == smp_processor_id())
 312                         return 1;
 313         }
 314         return 0;
 315 }
 316
 317 /* call with IRQ disabled */
 318 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 319                              struct net_device *dev)
 320 {
 321         int status = NETDEV_TX_BUSY;
 322         unsigned long tries;
 323         /* It is up to the caller to keep npinfo alive. */
 324         struct netpoll_info *npinfo;
 325
 326         WARN_ON_ONCE(!irqs_disabled());
 327
 328         npinfo = rcu_dereference_bh(np->dev->npinfo);
 329         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 330                 dev_kfree_skb_irq(skb);
 331                 return;
 332         }
 333
 334         /* don't get messages out of order, and no recursion */
 335         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 336                 struct netdev_queue *txq;
 337
 338                 txq = netdev_pick_tx(dev, skb, NULL);
 339
 340                 /* try until next clock tick */
 341                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 342                      tries > 0; --tries) {
 343                         if (HARD_TX_TRYLOCK(dev, txq)) {
 344                                 if (!netif_xmit_stopped(txq))
 345                                         status = netpoll_start_xmit(skb, dev, txq);
 346
 347                                 HARD_TX_UNLOCK(dev, txq);
 348
 349                                 if (status == NETDEV_TX_OK)
 350                                         break;
 351
 352                         }
 353
 354                         /* tickle device maybe there is some cleanup */
 355                         netpoll_poll_dev(np->dev);
 356
 357                         udelay(USEC_PER_POLL);
 358                 }
 359
 360                 WARN_ONCE(!irqs_disabled(),
 361                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 362                         dev->name, dev->netdev_ops->ndo_start_xmit);
 363
 364         }
 365
 366         if (status != NETDEV_TX_OK) {
 367                 skb_queue_tail(&npinfo->txq, skb);
 368                 schedule_delayed_work(&npinfo->tx_work,0);
 369         }
 370 }
 371 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 372
 373 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 374 {
 375         int total_len, ip_len, udp_len;
 376         struct sk_buff *skb;
 377         struct udphdr *udph;
 378         struct iphdr *iph;
 379         struct ethhdr *eth;
 380         static atomic_t ip_ident;
 381         struct ipv6hdr *ip6h;
 382
 383         udp_len = len + sizeof(*udph);
 384         if (np->ipv6)
 385                 ip_len = udp_len + sizeof(*ip6h);
 386         else
 387                 ip_len = udp_len + sizeof(*iph);
 388
 389         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 390
 391         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 392                        total_len - len);
 393         if (!skb)
 394                 return;
 395
 396         skb_copy_to_linear_data(skb, msg, len);
 397         skb_put(skb, len);
 398
 399         skb_push(skb, sizeof(*udph));
 400         skb_reset_transport_header(skb);
 401         udph = udp_hdr(skb);
 402         udph->source = htons(np->local_port);
 403         udph->dest = htons(np->remote_port);
 404         udph->len = htons(udp_len);
 405
 406         if (np->ipv6) {
 407                 udph->check = 0;
 408                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 409                                               &np->remote_ip.in6,
 410                                               udp_len, IPPROTO_UDP,
 411                                               csum_partial(udph, udp_len, 0));
 412                 if (udph->check == 0)
 413                         udph->check = CSUM_MANGLED_0;
 414
 415                 skb_push(skb, sizeof(*ip6h));
 416                 skb_reset_network_header(skb);
 417                 ip6h = ipv6_hdr(skb);
 418
 419                 /* ip6h->version = 6; ip6h->priority = 0; */
 420                 put_unaligned(0x60, (unsigned char *)ip6h);
 421                 ip6h->flow_lbl[0] = 0;
 422                 ip6h->flow_lbl[1] = 0;
 423                 ip6h->flow_lbl[2] = 0;
 424
 425                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 426                 ip6h->nexthdr = IPPROTO_UDP;
 427                 ip6h->hop_limit = 32;
 428                 ip6h->saddr = np->local_ip.in6;
 429                 ip6h->daddr = np->remote_ip.in6;
 430
 431                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 432                 skb_reset_mac_header(skb);
 433                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 434         } else {
 435                 udph->check = 0;
 436                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 437                                                 np->remote_ip.ip,
 438                                                 udp_len, IPPROTO_UDP,
 439                                                 csum_partial(udph, udp_len, 0));
 440                 if (udph->check == 0)
 441                         udph->check = CSUM_MANGLED_0;
 442
 443                 skb_push(skb, sizeof(*iph));
 444                 skb_reset_network_header(skb);
 445                 iph = ip_hdr(skb);
 446
 447                 /* iph->version = 4; iph->ihl = 5; */
 448                 put_unaligned(0x45, (unsigned char *)iph);
 449                 iph->tos      = 0;
 450                 put_unaligned(htons(ip_len), &(iph->tot_len));
 451                 iph->id       = htons(atomic_inc_return(&ip_ident));
 452                 iph->frag_off = 0;
 453                 iph->ttl      = 64;
 454                 iph->protocol = IPPROTO_UDP;
 455                 iph->check    = 0;
 456                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 457                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 458                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 459
 460                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 461                 skb_reset_mac_header(skb);
 462                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 463         }
 464
 465         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 466         ether_addr_copy(eth->h_dest, np->remote_mac);
 467
 468         skb->dev = np->dev;
 469
 470         netpoll_send_skb(np, skb);
 471 }
 472 EXPORT_SYMBOL(netpoll_send_udp);
 473
 474 void netpoll_print_options(struct netpoll *np)
 475 {
 476         np_info(np, "local port %d\n", np->local_port);
 477         if (np->ipv6)
 478                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 479         else
 480                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 481         np_info(np, "interface '%s'\n", np->dev_name);
 482         np_info(np, "remote port %d\n", np->remote_port);
 483         if (np->ipv6)
 484                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 485         else
 486                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 487         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 488 }
 489 EXPORT_SYMBOL(netpoll_print_options);
 490
 491 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 492 {
 493         const char *end;
 494
 495         if (!strchr(str, ':') &&
 496             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 497                 if (!*end)
 498                         return 0;
 499         }
 500         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 501 #if IS_ENABLED(CONFIG_IPV6)
 502                 if (!*end)
 503                         return 1;
 504 #else
 505                 return -1;
 506 #endif
 507         }
 508         return -1;
 509 }
 510
 511 int netpoll_parse_options(struct netpoll *np, char *opt)
 512 {
 513         char *cur=opt, *delim;
 514         int ipv6;
 515         bool ipversion_set = false;
 516
 517         if (*cur != '@') {
 518                 if ((delim = strchr(cur, '@')) == NULL)
 519                         goto parse_failed;
 520                 *delim = 0;
 521                 if (kstrtou16(cur, 10, &np->local_port))
 522                         goto parse_failed;
 523                 cur = delim;
 524         }
 525         cur++;
 526
 527         if (*cur != '/') {
 528                 ipversion_set = true;
 529                 if ((delim = strchr(cur, '/')) == NULL)
 530                         goto parse_failed;
 531                 *delim = 0;
 532                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 533                 if (ipv6 < 0)
 534                         goto parse_failed;
 535                 else
 536                         np->ipv6 = (bool)ipv6;
 537                 cur = delim;
 538         }
 539         cur++;
 540
 541         if (*cur != ',') {
 542                 /* parse out dev name */
 543                 if ((delim = strchr(cur, ',')) == NULL)
 544                         goto parse_failed;
 545                 *delim = 0;
 546                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 547                 cur = delim;
 548         }
 549         cur++;
 550
 551         if (*cur != '@') {
 552                 /* dst port */
 553                 if ((delim = strchr(cur, '@')) == NULL)
 554                         goto parse_failed;
 555                 *delim = 0;
 556                 if (*cur == ' ' || *cur == '\t')
 557                         np_info(np, "warning: whitespace is not allowed\n");
 558                 if (kstrtou16(cur, 10, &np->remote_port))
 559                         goto parse_failed;
 560                 cur = delim;
 561         }
 562         cur++;
 563
 564         /* dst ip */
 565         if ((delim = strchr(cur, '/')) == NULL)
 566                 goto parse_failed;
 567         *delim = 0;
 568         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 569         if (ipv6 < 0)
 570                 goto parse_failed;
 571         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 572                 goto parse_failed;
 573         else
 574                 np->ipv6 = (bool)ipv6;
 575         cur = delim + 1;
 576
 577         if (*cur != 0) {
 578                 /* MAC address */
 579                 if (!mac_pton(cur, np->remote_mac))
 580                         goto parse_failed;
 581         }
 582
 583         netpoll_print_options(np);
 584
 585         return 0;
 586
 587  parse_failed:
 588         np_info(np, "couldn't parse config at '%s'!\n", cur);
 589         return -1;
 590 }
 591 EXPORT_SYMBOL(netpoll_parse_options);
 592
 593 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 594 {
 595         struct netpoll_info *npinfo;
 596         const struct net_device_ops *ops;
 597         int err;
 598
 599         np->dev = ndev;
 600         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 601         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
 602
 603         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 604             !ndev->netdev_ops->ndo_poll_controller) {
 605                 np_err(np, "%s doesn't support polling, aborting\n",
 606                        np->dev_name);
 607                 err = -ENOTSUPP;
 608                 goto out;
 609         }
 610
 611         if (!ndev->npinfo) {
 612                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 613                 if (!npinfo) {
 614                         err = -ENOMEM;
 615                         goto out;
 616                 }
 617
 618                 sema_init(&npinfo->dev_lock, 1);
 619                 skb_queue_head_init(&npinfo->txq);
 620                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 621
 622                 atomic_set(&npinfo->refcnt, 1);
 623
 624                 ops = np->dev->netdev_ops;
 625                 if (ops->ndo_netpoll_setup) {
 626                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 627                         if (err)
 628                                 goto free_npinfo;
 629                 }
 630         } else {
 631                 npinfo = rtnl_dereference(ndev->npinfo);
 632                 atomic_inc(&npinfo->refcnt);
 633         }
 634
 635         npinfo->netpoll = np;
 636
 637         /* last thing to do is link it to the net device structure */
 638         rcu_assign_pointer(ndev->npinfo, npinfo);
 639
 640         return 0;
 641
 642 free_npinfo:
 643         kfree(npinfo);
 644 out:
 645         return err;
 646 }
 647 EXPORT_SYMBOL_GPL(__netpoll_setup);
 648
 649 int netpoll_setup(struct netpoll *np)
 650 {
 651         struct net_device *ndev = NULL;
 652         struct in_device *in_dev;
 653         int err;
 654
 655         rtnl_lock();
 656         if (np->dev_name) {
 657                 struct net *net = current->nsproxy->net_ns;
 658                 ndev = __dev_get_by_name(net, np->dev_name);
 659         }
 660         if (!ndev) {
 661                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 662                 err = -ENODEV;
 663                 goto unlock;
 664         }
 665         dev_hold(ndev);
 666
 667         if (netdev_master_upper_dev_get(ndev)) {
 668                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 669                 err = -EBUSY;
 670                 goto put;
 671         }
 672
 673         if (!netif_running(ndev)) {
 674                 unsigned long atmost, atleast;
 675
 676                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 677
 678                 err = dev_open(ndev);
 679
 680                 if (err) {
 681                         np_err(np, "failed to open %s\n", ndev->name);
 682                         goto put;
 683                 }
 684
 685                 rtnl_unlock();
 686                 atleast = jiffies + HZ/10;
 687                 atmost = jiffies + carrier_timeout * HZ;
 688                 while (!netif_carrier_ok(ndev)) {
 689                         if (time_after(jiffies, atmost)) {
 690                                 np_notice(np, "timeout waiting for carrier\n");
 691                                 break;
 692                         }
 693                         msleep(1);
 694                 }
 695
 696                 /* If carrier appears to come up instantly, we don't
 697                  * trust it and pause so that we don't pump all our
 698                  * queued console messages into the bitbucket.
 699                  */
 700
 701                 if (time_before(jiffies, atleast)) {
 702                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 703                         msleep(4000);
 704                 }
 705                 rtnl_lock();
 706         }
 707
 708         if (!np->local_ip.ip) {
 709                 if (!np->ipv6) {
 710                         in_dev = __in_dev_get_rtnl(ndev);
 711
 712                         if (!in_dev || !in_dev->ifa_list) {
 713                                 np_err(np, "no IP address for %s, aborting\n",
 714                                        np->dev_name);
 715                                 err = -EDESTADDRREQ;
 716                                 goto put;
 717                         }
 718
 719                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
 720                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 721                 } else {
 722 #if IS_ENABLED(CONFIG_IPV6)
 723                         struct inet6_dev *idev;
 724
 725                         err = -EDESTADDRREQ;
 726                         idev = __in6_dev_get(ndev);
 727                         if (idev) {
 728                                 struct inet6_ifaddr *ifp;
 729
 730                                 read_lock_bh(&idev->lock);
 731                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 732                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
 733                                                 continue;
 734                                         np->local_ip.in6 = ifp->addr;
 735                                         err = 0;
 736                                         break;
 737                                 }
 738                                 read_unlock_bh(&idev->lock);
 739                         }
 740                         if (err) {
 741                                 np_err(np, "no IPv6 address for %s, aborting\n",
 742                                        np->dev_name);
 743                                 goto put;
 744                         } else
 745                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 746 #else
 747                         np_err(np, "IPv6 is not supported %s, aborting\n",
 748                                np->dev_name);
 749                         err = -EINVAL;
 750                         goto put;
 751 #endif
 752                 }
 753         }
 754
 755         /* fill up the skb queue */
 756         refill_skbs();
 757
 758         err = __netpoll_setup(np, ndev);
 759         if (err)
 760                 goto put;
 761
 762         rtnl_unlock();
 763         return 0;
 764
 765 put:
 766         dev_put(ndev);
 767 unlock:
 768         rtnl_unlock();
 769         return err;
 770 }
 771 EXPORT_SYMBOL(netpoll_setup);
 772
 773 static int __init netpoll_init(void)
 774 {
 775         skb_queue_head_init(&skb_pool);
 776         return 0;
 777 }
 778 core_initcall(netpoll_init);
 779
 780 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 781 {
 782         struct netpoll_info *npinfo =
 783                         container_of(rcu_head, struct netpoll_info, rcu);
 784
 785         skb_queue_purge(&npinfo->txq);
 786
 787         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 788         cancel_delayed_work(&npinfo->tx_work);
 789
 790         /* clean after last, unfinished work */
 791         __skb_queue_purge(&npinfo->txq);
 792         /* now cancel it again */
 793         cancel_delayed_work(&npinfo->tx_work);
 794         kfree(npinfo);
 795 }
 796
 797 void __netpoll_cleanup(struct netpoll *np)
 798 {
 799         struct netpoll_info *npinfo;
 800
 801         /* rtnl_dereference would be preferable here but
 802          * rcu_cleanup_netpoll path can put us in here safely without
 803          * holding the rtnl, so plain rcu_dereference it is
 804          */
 805         npinfo = rtnl_dereference(np->dev->npinfo);
 806         if (!npinfo)
 807                 return;
 808
 809         synchronize_srcu(&netpoll_srcu);
 810
 811         if (atomic_dec_and_test(&npinfo->refcnt)) {
 812                 const struct net_device_ops *ops;
 813
 814                 ops = np->dev->netdev_ops;
 815                 if (ops->ndo_netpoll_cleanup)
 816                         ops->ndo_netpoll_cleanup(np->dev);
 817
 818                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 819                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
 820         } else
 821                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 822 }
 823 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 824
 825 static void netpoll_async_cleanup(struct work_struct *work)
 826 {
 827         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
 828
 829         rtnl_lock();
 830         __netpoll_cleanup(np);
 831         rtnl_unlock();
 832         kfree(np);
 833 }
 834
 835 void __netpoll_free_async(struct netpoll *np)
 836 {
 837         schedule_work(&np->cleanup_work);
 838 }
 839 EXPORT_SYMBOL_GPL(__netpoll_free_async);
 840
 841 void netpoll_cleanup(struct netpoll *np)
 842 {
 843         rtnl_lock();
 844         if (!np->dev)
 845                 goto out;
 846         __netpoll_cleanup(np);
 847         dev_put(np->dev);
 848         np->dev = NULL;
 849 out:
 850         rtnl_unlock();
 851 }
 852 EXPORT_SYMBOL(netpoll_cleanup);