net/core/netpoll.c

   1 /*
   2  * Common framework for low-level network console, dump, and debugger code
   3  *
   4  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
   5  *
   6  * based on the netconsole code from:
   7  *
   8  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
   9  * Copyright (C) 2002  Red Hat, Inc.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/moduleparam.h>
  15 #include <linux/kernel.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/string.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/inetdevice.h>
  21 #include <linux/inet.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/netpoll.h>
  24 #include <linux/sched.h>
  25 #include <linux/delay.h>
  26 #include <linux/rcupdate.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/slab.h>
  29 #include <linux/export.h>
  30 #include <linux/if_vlan.h>
  31 #include <net/tcp.h>
  32 #include <net/udp.h>
  33 #include <net/addrconf.h>
  34 #include <net/ndisc.h>
  35 #include <net/ip6_checksum.h>
  36 #include <asm/unaligned.h>
  37 #include <trace/events/napi.h>
  38
  39 /*
  40  * We maintain a small pool of fully-sized skbs, to make sure the
  41  * message gets out even in extreme OOM situations.
  42  */
  43
  44 #define MAX_UDP_CHUNK 1460
  45 #define MAX_SKBS 32
  46
  47 static struct sk_buff_head skb_pool;
  48
  49 DEFINE_STATIC_SRCU(netpoll_srcu);
  50
  51 #define USEC_PER_POLL   50
  52
  53 #define MAX_SKB_SIZE                                                    \
  54         (sizeof(struct ethhdr) +                                        \
  55          sizeof(struct iphdr) +                                         \
  56          sizeof(struct udphdr) +                                        \
  57          MAX_UDP_CHUNK)
  58
  59 static void zap_completion_queue(void);
  60 static void netpoll_async_cleanup(struct work_struct *work);
  61
  62 static unsigned int carrier_timeout = 4;
  63 module_param(carrier_timeout, uint, 0644);
  64
  65 #define np_info(np, fmt, ...)                           \
  66         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  67 #define np_err(np, fmt, ...)                            \
  68         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  69 #define np_notice(np, fmt, ...)                         \
  70         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  71
  72 static int netpoll_start_xmit(struct sk_buff *skb, struct net_device *dev,
  73                               struct netdev_queue *txq)
  74 {
  75         int status = NETDEV_TX_OK;
  76         netdev_features_t features;
  77
  78         features = netif_skb_features(skb);
  79
  80         if (skb_vlan_tag_present(skb) &&
  81             !vlan_hw_offload_capable(features, skb->vlan_proto)) {
  82                 skb = __vlan_hwaccel_push_inside(skb);
  83                 if (unlikely(!skb)) {
  84                         /* This is actually a packet drop, but we
  85                          * don't want the code that calls this
  86                          * function to try and operate on a NULL skb.
  87                          */
  88                         goto out;
  89                 }
  90         }
  91
  92         status = netdev_start_xmit(skb, dev, txq, false);
  93
  94 out:
  95         return status;
  96 }
  97
  98 static void queue_process(struct work_struct *work)
  99 {
 100         struct netpoll_info *npinfo =
 101                 container_of(work, struct netpoll_info, tx_work.work);
 102         struct sk_buff *skb;
 103         unsigned long flags;
 104
 105         while ((skb = skb_dequeue(&npinfo->txq))) {
 106                 struct net_device *dev = skb->dev;
 107                 struct netdev_queue *txq;
 108
 109                 if (!netif_device_present(dev) || !netif_running(dev)) {
 110                         kfree_skb(skb);
 111                         continue;
 112                 }
 113
 114                 txq = skb_get_tx_queue(dev, skb);
 115
 116                 local_irq_save(flags);
 117                 HARD_TX_LOCK(dev, txq, smp_processor_id());
 118                 if (netif_xmit_frozen_or_stopped(txq) ||
 119                     netpoll_start_xmit(skb, dev, txq) != NETDEV_TX_OK) {
 120                         skb_queue_head(&npinfo->txq, skb);
 121                         HARD_TX_UNLOCK(dev, txq);
 122                         local_irq_restore(flags);
 123
 124                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 125                         return;
 126                 }
 127                 HARD_TX_UNLOCK(dev, txq);
 128                 local_irq_restore(flags);
 129         }
 130 }
 131
 132 /*
 133  * Check whether delayed processing was scheduled for our NIC. If so,
 134  * we attempt to grab the poll lock and use ->poll() to pump the card.
 135  * If this fails, either we've recursed in ->poll() or it's already
 136  * running on another CPU.
 137  *
 138  * Note: we don't mask interrupts with this lock because we're using
 139  * trylock here and interrupts are already disabled in the softirq
 140  * case. Further, we test the poll_owner to avoid recursion on UP
 141  * systems where the lock doesn't exist.
 142  */
 143 static int poll_one_napi(struct napi_struct *napi, int budget)
 144 {
 145         int work = 0;
 146
 147         /* net_rx_action's ->poll() invocations and our's are
 148          * synchronized by this test which is only made while
 149          * holding the napi->poll_lock.
 150          */
 151         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 152                 return budget;
 153
 154         /* If we set this bit but see that it has already been set,
 155          * that indicates that napi has been disabled and we need
 156          * to abort this operation
 157          */
 158         if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
 159                 goto out;
 160
 161         work = napi->poll(napi, budget);
 162         WARN_ONCE(work > budget, "%pF exceeded budget in poll\n", napi->poll);
 163         trace_napi_poll(napi);
 164
 165         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 166
 167 out:
 168         return budget - work;
 169 }
 170
 171 static void poll_napi(struct net_device *dev, int budget)
 172 {
 173         struct napi_struct *napi;
 174
 175         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 176                 if (napi->poll_owner != smp_processor_id() &&
 177                     spin_trylock(&napi->poll_lock)) {
 178                         budget = poll_one_napi(napi, budget);
 179                         spin_unlock(&napi->poll_lock);
 180                 }
 181         }
 182 }
 183
 184 static void netpoll_poll_dev(struct net_device *dev)
 185 {
 186         const struct net_device_ops *ops;
 187         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 188         int budget = 0;
 189
 190         /* Don't do any rx activity if the dev_lock mutex is held
 191          * the dev_open/close paths use this to block netpoll activity
 192          * while changing device state
 193          */
 194         if (down_trylock(&ni->dev_lock))
 195                 return;
 196
 197         if (!netif_running(dev)) {
 198                 up(&ni->dev_lock);
 199                 return;
 200         }
 201
 202         ops = dev->netdev_ops;
 203         if (!ops->ndo_poll_controller) {
 204                 up(&ni->dev_lock);
 205                 return;
 206         }
 207
 208         /* Process pending work on NIC */
 209         ops->ndo_poll_controller(dev);
 210
 211         poll_napi(dev, budget);
 212
 213         up(&ni->dev_lock);
 214
 215         zap_completion_queue();
 216 }
 217
 218 void netpoll_poll_disable(struct net_device *dev)
 219 {
 220         struct netpoll_info *ni;
 221         int idx;
 222         might_sleep();
 223         idx = srcu_read_lock(&netpoll_srcu);
 224         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 225         if (ni)
 226                 down(&ni->dev_lock);
 227         srcu_read_unlock(&netpoll_srcu, idx);
 228 }
 229 EXPORT_SYMBOL(netpoll_poll_disable);
 230
 231 void netpoll_poll_enable(struct net_device *dev)
 232 {
 233         struct netpoll_info *ni;
 234         rcu_read_lock();
 235         ni = rcu_dereference(dev->npinfo);
 236         if (ni)
 237                 up(&ni->dev_lock);
 238         rcu_read_unlock();
 239 }
 240 EXPORT_SYMBOL(netpoll_poll_enable);
 241
 242 static void refill_skbs(void)
 243 {
 244         struct sk_buff *skb;
 245         unsigned long flags;
 246
 247         spin_lock_irqsave(&skb_pool.lock, flags);
 248         while (skb_pool.qlen < MAX_SKBS) {
 249                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 250                 if (!skb)
 251                         break;
 252
 253                 __skb_queue_tail(&skb_pool, skb);
 254         }
 255         spin_unlock_irqrestore(&skb_pool.lock, flags);
 256 }
 257
 258 static void zap_completion_queue(void)
 259 {
 260         unsigned long flags;
 261         struct softnet_data *sd = &get_cpu_var(softnet_data);
 262
 263         if (sd->completion_queue) {
 264                 struct sk_buff *clist;
 265
 266                 local_irq_save(flags);
 267                 clist = sd->completion_queue;
 268                 sd->completion_queue = NULL;
 269                 local_irq_restore(flags);
 270
 271                 while (clist != NULL) {
 272                         struct sk_buff *skb = clist;
 273                         clist = clist->next;
 274                         if (!skb_irq_freeable(skb)) {
 275                                 atomic_inc(&skb->users);
 276                                 dev_kfree_skb_any(skb); /* put this one back */
 277                         } else {
 278                                 __kfree_skb(skb);
 279                         }
 280                 }
 281         }
 282
 283         put_cpu_var(softnet_data);
 284 }
 285
 286 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 287 {
 288         int count = 0;
 289         struct sk_buff *skb;
 290
 291         zap_completion_queue();
 292         refill_skbs();
 293 repeat:
 294
 295         skb = alloc_skb(len, GFP_ATOMIC);
 296         if (!skb)
 297                 skb = skb_dequeue(&skb_pool);
 298
 299         if (!skb) {
 300                 if (++count < 10) {
 301                         netpoll_poll_dev(np->dev);
 302                         goto repeat;
 303                 }
 304                 return NULL;
 305         }
 306
 307         atomic_set(&skb->users, 1);
 308         skb_reserve(skb, reserve);
 309         return skb;
 310 }
 311
 312 static int netpoll_owner_active(struct net_device *dev)
 313 {
 314         struct napi_struct *napi;
 315
 316         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 317                 if (napi->poll_owner == smp_processor_id())
 318                         return 1;
 319         }
 320         return 0;
 321 }
 322
 323 /* call with IRQ disabled */
 324 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 325                              struct net_device *dev)
 326 {
 327         int status = NETDEV_TX_BUSY;
 328         unsigned long tries;
 329         /* It is up to the caller to keep npinfo alive. */
 330         struct netpoll_info *npinfo;
 331
 332         WARN_ON_ONCE(!irqs_disabled());
 333
 334         npinfo = rcu_dereference_bh(np->dev->npinfo);
 335         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 336                 dev_kfree_skb_irq(skb);
 337                 return;
 338         }
 339
 340         /* don't get messages out of order, and no recursion */
 341         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 342                 struct netdev_queue *txq;
 343
 344                 txq = netdev_pick_tx(dev, skb, NULL);
 345
 346                 /* try until next clock tick */
 347                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 348                      tries > 0; --tries) {
 349                         if (HARD_TX_TRYLOCK(dev, txq)) {
 350                                 if (!netif_xmit_stopped(txq))
 351                                         status = netpoll_start_xmit(skb, dev, txq);
 352
 353                                 HARD_TX_UNLOCK(dev, txq);
 354
 355                                 if (status == NETDEV_TX_OK)
 356                                         break;
 357
 358                         }
 359
 360                         /* tickle device maybe there is some cleanup */
 361                         netpoll_poll_dev(np->dev);
 362
 363                         udelay(USEC_PER_POLL);
 364                 }
 365
 366                 WARN_ONCE(!irqs_disabled(),
 367                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 368                         dev->name, dev->netdev_ops->ndo_start_xmit);
 369
 370         }
 371
 372         if (status != NETDEV_TX_OK) {
 373                 skb_queue_tail(&npinfo->txq, skb);
 374                 schedule_delayed_work(&npinfo->tx_work,0);
 375         }
 376 }
 377 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 378
 379 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 380 {
 381         int total_len, ip_len, udp_len;
 382         struct sk_buff *skb;
 383         struct udphdr *udph;
 384         struct iphdr *iph;
 385         struct ethhdr *eth;
 386         static atomic_t ip_ident;
 387         struct ipv6hdr *ip6h;
 388
 389         WARN_ON_ONCE(!irqs_disabled());
 390
 391         udp_len = len + sizeof(*udph);
 392         if (np->ipv6)
 393                 ip_len = udp_len + sizeof(*ip6h);
 394         else
 395                 ip_len = udp_len + sizeof(*iph);
 396
 397         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 398
 399         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 400                        total_len - len);
 401         if (!skb)
 402                 return;
 403
 404         skb_copy_to_linear_data(skb, msg, len);
 405         skb_put(skb, len);
 406
 407         skb_push(skb, sizeof(*udph));
 408         skb_reset_transport_header(skb);
 409         udph = udp_hdr(skb);
 410         udph->source = htons(np->local_port);
 411         udph->dest = htons(np->remote_port);
 412         udph->len = htons(udp_len);
 413
 414         if (np->ipv6) {
 415                 udph->check = 0;
 416                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 417                                               &np->remote_ip.in6,
 418                                               udp_len, IPPROTO_UDP,
 419                                               csum_partial(udph, udp_len, 0));
 420                 if (udph->check == 0)
 421                         udph->check = CSUM_MANGLED_0;
 422
 423                 skb_push(skb, sizeof(*ip6h));
 424                 skb_reset_network_header(skb);
 425                 ip6h = ipv6_hdr(skb);
 426
 427                 /* ip6h->version = 6; ip6h->priority = 0; */
 428                 put_unaligned(0x60, (unsigned char *)ip6h);
 429                 ip6h->flow_lbl[0] = 0;
 430                 ip6h->flow_lbl[1] = 0;
 431                 ip6h->flow_lbl[2] = 0;
 432
 433                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 434                 ip6h->nexthdr = IPPROTO_UDP;
 435                 ip6h->hop_limit = 32;
 436                 ip6h->saddr = np->local_ip.in6;
 437                 ip6h->daddr = np->remote_ip.in6;
 438
 439                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 440                 skb_reset_mac_header(skb);
 441                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 442         } else {
 443                 udph->check = 0;
 444                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 445                                                 np->remote_ip.ip,
 446                                                 udp_len, IPPROTO_UDP,
 447                                                 csum_partial(udph, udp_len, 0));
 448                 if (udph->check == 0)
 449                         udph->check = CSUM_MANGLED_0;
 450
 451                 skb_push(skb, sizeof(*iph));
 452                 skb_reset_network_header(skb);
 453                 iph = ip_hdr(skb);
 454
 455                 /* iph->version = 4; iph->ihl = 5; */
 456                 put_unaligned(0x45, (unsigned char *)iph);
 457                 iph->tos      = 0;
 458                 put_unaligned(htons(ip_len), &(iph->tot_len));
 459                 iph->id       = htons(atomic_inc_return(&ip_ident));
 460                 iph->frag_off = 0;
 461                 iph->ttl      = 64;
 462                 iph->protocol = IPPROTO_UDP;
 463                 iph->check    = 0;
 464                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 465                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 466                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 467
 468                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 469                 skb_reset_mac_header(skb);
 470                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 471         }
 472
 473         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 474         ether_addr_copy(eth->h_dest, np->remote_mac);
 475
 476         skb->dev = np->dev;
 477
 478         netpoll_send_skb(np, skb);
 479 }
 480 EXPORT_SYMBOL(netpoll_send_udp);
 481
 482 void netpoll_print_options(struct netpoll *np)
 483 {
 484         np_info(np, "local port %d\n", np->local_port);
 485         if (np->ipv6)
 486                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 487         else
 488                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 489         np_info(np, "interface '%s'\n", np->dev_name);
 490         np_info(np, "remote port %d\n", np->remote_port);
 491         if (np->ipv6)
 492                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 493         else
 494                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 495         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 496 }
 497 EXPORT_SYMBOL(netpoll_print_options);
 498
 499 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 500 {
 501         const char *end;
 502
 503         if (!strchr(str, ':') &&
 504             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 505                 if (!*end)
 506                         return 0;
 507         }
 508         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 509 #if IS_ENABLED(CONFIG_IPV6)
 510                 if (!*end)
 511                         return 1;
 512 #else
 513                 return -1;
 514 #endif
 515         }
 516         return -1;
 517 }
 518
 519 int netpoll_parse_options(struct netpoll *np, char *opt)
 520 {
 521         char *cur=opt, *delim;
 522         int ipv6;
 523         bool ipversion_set = false;
 524
 525         if (*cur != '@') {
 526                 if ((delim = strchr(cur, '@')) == NULL)
 527                         goto parse_failed;
 528                 *delim = 0;
 529                 if (kstrtou16(cur, 10, &np->local_port))
 530                         goto parse_failed;
 531                 cur = delim;
 532         }
 533         cur++;
 534
 535         if (*cur != '/') {
 536                 ipversion_set = true;
 537                 if ((delim = strchr(cur, '/')) == NULL)
 538                         goto parse_failed;
 539                 *delim = 0;
 540                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 541                 if (ipv6 < 0)
 542                         goto parse_failed;
 543                 else
 544                         np->ipv6 = (bool)ipv6;
 545                 cur = delim;
 546         }
 547         cur++;
 548
 549         if (*cur != ',') {
 550                 /* parse out dev name */
 551                 if ((delim = strchr(cur, ',')) == NULL)
 552                         goto parse_failed;
 553                 *delim = 0;
 554                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 555                 cur = delim;
 556         }
 557         cur++;
 558
 559         if (*cur != '@') {
 560                 /* dst port */
 561                 if ((delim = strchr(cur, '@')) == NULL)
 562                         goto parse_failed;
 563                 *delim = 0;
 564                 if (*cur == ' ' || *cur == '\t')
 565                         np_info(np, "warning: whitespace is not allowed\n");
 566                 if (kstrtou16(cur, 10, &np->remote_port))
 567                         goto parse_failed;
 568                 cur = delim;
 569         }
 570         cur++;
 571
 572         /* dst ip */
 573         if ((delim = strchr(cur, '/')) == NULL)
 574                 goto parse_failed;
 575         *delim = 0;
 576         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 577         if (ipv6 < 0)
 578                 goto parse_failed;
 579         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 580                 goto parse_failed;
 581         else
 582                 np->ipv6 = (bool)ipv6;
 583         cur = delim + 1;
 584
 585         if (*cur != 0) {
 586                 /* MAC address */
 587                 if (!mac_pton(cur, np->remote_mac))
 588                         goto parse_failed;
 589         }
 590
 591         netpoll_print_options(np);
 592
 593         return 0;
 594
 595  parse_failed:
 596         np_info(np, "couldn't parse config at '%s'!\n", cur);
 597         return -1;
 598 }
 599 EXPORT_SYMBOL(netpoll_parse_options);
 600
 601 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 602 {
 603         struct netpoll_info *npinfo;
 604         const struct net_device_ops *ops;
 605         int err;
 606
 607         np->dev = ndev;
 608         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 609         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
 610
 611         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 612             !ndev->netdev_ops->ndo_poll_controller) {
 613                 np_err(np, "%s doesn't support polling, aborting\n",
 614                        np->dev_name);
 615                 err = -ENOTSUPP;
 616                 goto out;
 617         }
 618
 619         if (!ndev->npinfo) {
 620                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 621                 if (!npinfo) {
 622                         err = -ENOMEM;
 623                         goto out;
 624                 }
 625
 626                 sema_init(&npinfo->dev_lock, 1);
 627                 skb_queue_head_init(&npinfo->txq);
 628                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 629
 630                 atomic_set(&npinfo->refcnt, 1);
 631
 632                 ops = np->dev->netdev_ops;
 633                 if (ops->ndo_netpoll_setup) {
 634                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 635                         if (err)
 636                                 goto free_npinfo;
 637                 }
 638         } else {
 639                 npinfo = rtnl_dereference(ndev->npinfo);
 640                 atomic_inc(&npinfo->refcnt);
 641         }
 642
 643         npinfo->netpoll = np;
 644
 645         /* last thing to do is link it to the net device structure */
 646         rcu_assign_pointer(ndev->npinfo, npinfo);
 647
 648         return 0;
 649
 650 free_npinfo:
 651         kfree(npinfo);
 652 out:
 653         return err;
 654 }
 655 EXPORT_SYMBOL_GPL(__netpoll_setup);
 656
 657 int netpoll_setup(struct netpoll *np)
 658 {
 659         struct net_device *ndev = NULL;
 660         struct in_device *in_dev;
 661         int err;
 662
 663         rtnl_lock();
 664         if (np->dev_name) {
 665                 struct net *net = current->nsproxy->net_ns;
 666                 ndev = __dev_get_by_name(net, np->dev_name);
 667         }
 668         if (!ndev) {
 669                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 670                 err = -ENODEV;
 671                 goto unlock;
 672         }
 673         dev_hold(ndev);
 674
 675         if (netdev_master_upper_dev_get(ndev)) {
 676                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 677                 err = -EBUSY;
 678                 goto put;
 679         }
 680
 681         if (!netif_running(ndev)) {
 682                 unsigned long atmost, atleast;
 683
 684                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 685
 686                 err = dev_open(ndev);
 687
 688                 if (err) {
 689                         np_err(np, "failed to open %s\n", ndev->name);
 690                         goto put;
 691                 }
 692
 693                 rtnl_unlock();
 694                 atleast = jiffies + HZ/10;
 695                 atmost = jiffies + carrier_timeout * HZ;
 696                 while (!netif_carrier_ok(ndev)) {
 697                         if (time_after(jiffies, atmost)) {
 698                                 np_notice(np, "timeout waiting for carrier\n");
 699                                 break;
 700                         }
 701                         msleep(1);
 702                 }
 703
 704                 /* If carrier appears to come up instantly, we don't
 705                  * trust it and pause so that we don't pump all our
 706                  * queued console messages into the bitbucket.
 707                  */
 708
 709                 if (time_before(jiffies, atleast)) {
 710                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 711                         msleep(4000);
 712                 }
 713                 rtnl_lock();
 714         }
 715
 716         if (!np->local_ip.ip) {
 717                 if (!np->ipv6) {
 718                         in_dev = __in_dev_get_rtnl(ndev);
 719
 720                         if (!in_dev || !in_dev->ifa_list) {
 721                                 np_err(np, "no IP address for %s, aborting\n",
 722                                        np->dev_name);
 723                                 err = -EDESTADDRREQ;
 724                                 goto put;
 725                         }
 726
 727                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
 728                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 729                 } else {
 730 #if IS_ENABLED(CONFIG_IPV6)
 731                         struct inet6_dev *idev;
 732
 733                         err = -EDESTADDRREQ;
 734                         idev = __in6_dev_get(ndev);
 735                         if (idev) {
 736                                 struct inet6_ifaddr *ifp;
 737
 738                                 read_lock_bh(&idev->lock);
 739                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 740                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
 741                                                 continue;
 742                                         np->local_ip.in6 = ifp->addr;
 743                                         err = 0;
 744                                         break;
 745                                 }
 746                                 read_unlock_bh(&idev->lock);
 747                         }
 748                         if (err) {
 749                                 np_err(np, "no IPv6 address for %s, aborting\n",
 750                                        np->dev_name);
 751                                 goto put;
 752                         } else
 753                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 754 #else
 755                         np_err(np, "IPv6 is not supported %s, aborting\n",
 756                                np->dev_name);
 757                         err = -EINVAL;
 758                         goto put;
 759 #endif
 760                 }
 761         }
 762
 763         /* fill up the skb queue */
 764         refill_skbs();
 765
 766         err = __netpoll_setup(np, ndev);
 767         if (err)
 768                 goto put;
 769
 770         rtnl_unlock();
 771         return 0;
 772
 773 put:
 774         dev_put(ndev);
 775 unlock:
 776         rtnl_unlock();
 777         return err;
 778 }
 779 EXPORT_SYMBOL(netpoll_setup);
 780
 781 static int __init netpoll_init(void)
 782 {
 783         skb_queue_head_init(&skb_pool);
 784         return 0;
 785 }
 786 core_initcall(netpoll_init);
 787
 788 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 789 {
 790         struct netpoll_info *npinfo =
 791                         container_of(rcu_head, struct netpoll_info, rcu);
 792
 793         skb_queue_purge(&npinfo->txq);
 794
 795         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 796         cancel_delayed_work(&npinfo->tx_work);
 797
 798         /* clean after last, unfinished work */
 799         __skb_queue_purge(&npinfo->txq);
 800         /* now cancel it again */
 801         cancel_delayed_work(&npinfo->tx_work);
 802         kfree(npinfo);
 803 }
 804
 805 void __netpoll_cleanup(struct netpoll *np)
 806 {
 807         struct netpoll_info *npinfo;
 808
 809         /* rtnl_dereference would be preferable here but
 810          * rcu_cleanup_netpoll path can put us in here safely without
 811          * holding the rtnl, so plain rcu_dereference it is
 812          */
 813         npinfo = rtnl_dereference(np->dev->npinfo);
 814         if (!npinfo)
 815                 return;
 816
 817         synchronize_srcu(&netpoll_srcu);
 818
 819         if (atomic_dec_and_test(&npinfo->refcnt)) {
 820                 const struct net_device_ops *ops;
 821
 822                 ops = np->dev->netdev_ops;
 823                 if (ops->ndo_netpoll_cleanup)
 824                         ops->ndo_netpoll_cleanup(np->dev);
 825
 826                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 827                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
 828         } else
 829                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 830 }
 831 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 832
 833 static void netpoll_async_cleanup(struct work_struct *work)
 834 {
 835         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
 836
 837         rtnl_lock();
 838         __netpoll_cleanup(np);
 839         rtnl_unlock();
 840         kfree(np);
 841 }
 842
 843 void __netpoll_free_async(struct netpoll *np)
 844 {
 845         schedule_work(&np->cleanup_work);
 846 }
 847 EXPORT_SYMBOL_GPL(__netpoll_free_async);
 848
 849 void netpoll_cleanup(struct netpoll *np)
 850 {
 851         rtnl_lock();
 852         if (!np->dev)
 853                 goto out;
 854         __netpoll_cleanup(np);
 855         dev_put(np->dev);
 856         np->dev = NULL;
 857 out:
 858         rtnl_unlock();
 859 }
 860 EXPORT_SYMBOL(netpoll_cleanup);