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