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/dsa.h>
  32 #include <net/tcp.h>
  33 #include <net/udp.h>
  34 #include <net/addrconf.h>
  35 #include <net/ndisc.h>
  36 #include <net/ip6_checksum.h>
  37 #include <asm/unaligned.h>
  38 #include <trace/events/napi.h>
  39
  40 /*
  41  * We maintain a small pool of fully-sized skbs, to make sure the
  42  * message gets out even in extreme OOM situations.
  43  */
  44
  45 #define MAX_UDP_CHUNK 1460
  46 #define MAX_SKBS 32
  47
  48 static struct sk_buff_head skb_pool;
  49
  50 DEFINE_STATIC_SRCU(netpoll_srcu);
  51
  52 #define USEC_PER_POLL   50
  53
  54 #define MAX_SKB_SIZE                                                    \
  55         (sizeof(struct ethhdr) +                                        \
  56          sizeof(struct iphdr) +                                         \
  57          sizeof(struct udphdr) +                                        \
  58          MAX_UDP_CHUNK)
  59
  60 static void zap_completion_queue(void);
  61 static void netpoll_async_cleanup(struct work_struct *work);
  62
  63 static unsigned int carrier_timeout = 4;
  64 module_param(carrier_timeout, uint, 0644);
  65
  66 #define np_info(np, fmt, ...)                           \
  67         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  68 #define np_err(np, fmt, ...)                            \
  69         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  70 #define np_notice(np, fmt, ...)                         \
  71         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  72
  73 static int netpoll_start_xmit(struct sk_buff *skb, struct net_device *dev,
  74                               struct netdev_queue *txq)
  75 {
  76         int status = NETDEV_TX_OK;
  77         netdev_features_t features;
  78
  79         features = netif_skb_features(skb);
  80
  81         if (skb_vlan_tag_present(skb) &&
  82             !vlan_hw_offload_capable(features, skb->vlan_proto)) {
  83                 skb = __vlan_hwaccel_push_inside(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         }
  92
  93         status = netdev_start_xmit(skb, dev, txq, false);
  94
  95 out:
  96         return status;
  97 }
  98
  99 static void queue_process(struct work_struct *work)
 100 {
 101         struct netpoll_info *npinfo =
 102                 container_of(work, struct netpoll_info, tx_work.work);
 103         struct sk_buff *skb;
 104         unsigned long flags;
 105
 106         while ((skb = skb_dequeue(&npinfo->txq))) {
 107                 struct net_device *dev = skb->dev;
 108                 struct netdev_queue *txq;
 109                 unsigned int q_index;
 110
 111                 if (!netif_device_present(dev) || !netif_running(dev)) {
 112                         kfree_skb(skb);
 113                         continue;
 114                 }
 115
 116                 local_irq_save(flags);
 117                 /* check if skb->queue_mapping is still valid */
 118                 q_index = skb_get_queue_mapping(skb);
 119                 if (unlikely(q_index >= dev->real_num_tx_queues)) {
 120                         q_index = q_index % dev->real_num_tx_queues;
 121                         skb_set_queue_mapping(skb, q_index);
 122                 }
 123                 txq = netdev_get_tx_queue(dev, q_index);
 124                 HARD_TX_LOCK(dev, txq, smp_processor_id());
 125                 if (netif_xmit_frozen_or_stopped(txq) ||
 126                     !dev_xmit_complete(netpoll_start_xmit(skb, dev, txq))) {
 127                         skb_queue_head(&npinfo->txq, skb);
 128                         HARD_TX_UNLOCK(dev, txq);
 129                         local_irq_restore(flags);
 130
 131                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 132                         return;
 133                 }
 134                 HARD_TX_UNLOCK(dev, txq);
 135                 local_irq_restore(flags);
 136         }
 137 }
 138
 139 /*
 140  * Check whether delayed processing was scheduled for our NIC. If so,
 141  * we attempt to grab the poll lock and use ->poll() to pump the card.
 142  * If this fails, either we've recursed in ->poll() or it's already
 143  * running on another CPU.
 144  *
 145  * Note: we don't mask interrupts with this lock because we're using
 146  * trylock here and interrupts are already disabled in the softirq
 147  * case. Further, we test the poll_owner to avoid recursion on UP
 148  * systems where the lock doesn't exist.
 149  */
 150 static void poll_one_napi(struct napi_struct *napi)
 151 {
 152         int work = 0;
 153
 154         /* net_rx_action's ->poll() invocations and our's are
 155          * synchronized by this test which is only made while
 156          * holding the napi->poll_lock.
 157          */
 158         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 159                 return;
 160
 161         /* If we set this bit but see that it has already been set,
 162          * that indicates that napi has been disabled and we need
 163          * to abort this operation
 164          */
 165         if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
 166                 return;
 167
 168         /* We explicilty pass the polling call a budget of 0 to
 169          * indicate that we are clearing the Tx path only.
 170          */
 171         work = napi->poll(napi, 0);
 172         WARN_ONCE(work, "%pF exceeded budget in poll\n", napi->poll);
 173         trace_napi_poll(napi, work, 0);
 174
 175         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 176 }
 177
 178 static void poll_napi(struct net_device *dev)
 179 {
 180         struct napi_struct *napi;
 181
 182         list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
 183                 if (napi->poll_owner != smp_processor_id() &&
 184                     spin_trylock(&napi->poll_lock)) {
 185                         poll_one_napi(napi);
 186                         spin_unlock(&napi->poll_lock);
 187                 }
 188         }
 189 }
 190
 191 static void netpoll_poll_dev(struct net_device *dev)
 192 {
 193         const struct net_device_ops *ops;
 194         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 195
 196         /* Don't do any rx activity if the dev_lock mutex is held
 197          * the dev_open/close paths use this to block netpoll activity
 198          * while changing device state
 199          */
 200         if (down_trylock(&ni->dev_lock))
 201                 return;
 202
 203         if (!netif_running(dev)) {
 204                 up(&ni->dev_lock);
 205                 return;
 206         }
 207
 208         ops = dev->netdev_ops;
 209         if (!ops->ndo_poll_controller) {
 210                 up(&ni->dev_lock);
 211                 return;
 212         }
 213
 214         /* Process pending work on NIC */
 215         ops->ndo_poll_controller(dev);
 216
 217         poll_napi(dev);
 218
 219         up(&ni->dev_lock);
 220
 221         zap_completion_queue();
 222 }
 223
 224 void netpoll_poll_disable(struct net_device *dev)
 225 {
 226         struct netpoll_info *ni;
 227         int idx;
 228         might_sleep();
 229         idx = srcu_read_lock(&netpoll_srcu);
 230         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 231         if (ni)
 232                 down(&ni->dev_lock);
 233         srcu_read_unlock(&netpoll_srcu, idx);
 234 }
 235 EXPORT_SYMBOL(netpoll_poll_disable);
 236
 237 void netpoll_poll_enable(struct net_device *dev)
 238 {
 239         struct netpoll_info *ni;
 240         rcu_read_lock();
 241         ni = rcu_dereference(dev->npinfo);
 242         if (ni)
 243                 up(&ni->dev_lock);
 244         rcu_read_unlock();
 245 }
 246 EXPORT_SYMBOL(netpoll_poll_enable);
 247
 248 static void refill_skbs(void)
 249 {
 250         struct sk_buff *skb;
 251         unsigned long flags;
 252
 253         spin_lock_irqsave(&skb_pool.lock, flags);
 254         while (skb_pool.qlen < MAX_SKBS) {
 255                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 256                 if (!skb)
 257                         break;
 258
 259                 __skb_queue_tail(&skb_pool, skb);
 260         }
 261         spin_unlock_irqrestore(&skb_pool.lock, flags);
 262 }
 263
 264 static void zap_completion_queue(void)
 265 {
 266         unsigned long flags;
 267         struct softnet_data *sd = &get_cpu_var(softnet_data);
 268
 269         if (sd->completion_queue) {
 270                 struct sk_buff *clist;
 271
 272                 local_irq_save(flags);
 273                 clist = sd->completion_queue;
 274                 sd->completion_queue = NULL;
 275                 local_irq_restore(flags);
 276
 277                 while (clist != NULL) {
 278                         struct sk_buff *skb = clist;
 279                         clist = clist->next;
 280                         if (!skb_irq_freeable(skb)) {
 281                                 atomic_inc(&skb->users);
 282                                 dev_kfree_skb_any(skb); /* put this one back */
 283                         } else {
 284                                 __kfree_skb(skb);
 285                         }
 286                 }
 287         }
 288
 289         put_cpu_var(softnet_data);
 290 }
 291
 292 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 293 {
 294         int count = 0;
 295         struct sk_buff *skb;
 296
 297         zap_completion_queue();
 298         refill_skbs();
 299 repeat:
 300
 301         skb = alloc_skb(len, GFP_ATOMIC);
 302         if (!skb)
 303                 skb = skb_dequeue(&skb_pool);
 304
 305         if (!skb) {
 306                 if (++count < 10) {
 307                         netpoll_poll_dev(np->dev);
 308                         goto repeat;
 309                 }
 310                 return NULL;
 311         }
 312
 313         atomic_set(&skb->users, 1);
 314         skb_reserve(skb, reserve);
 315         return skb;
 316 }
 317
 318 static int netpoll_owner_active(struct net_device *dev)
 319 {
 320         struct napi_struct *napi;
 321
 322         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 323                 if (napi->poll_owner == smp_processor_id())
 324                         return 1;
 325         }
 326         return 0;
 327 }
 328
 329 /* call with IRQ disabled */
 330 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 331                              struct net_device *dev)
 332 {
 333         int status = NETDEV_TX_BUSY;
 334         unsigned long tries;
 335         /* It is up to the caller to keep npinfo alive. */
 336         struct netpoll_info *npinfo;
 337
 338         WARN_ON_ONCE(!irqs_disabled());
 339
 340         npinfo = rcu_dereference_bh(np->dev->npinfo);
 341         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 342                 dev_kfree_skb_irq(skb);
 343                 return;
 344         }
 345
 346         /* don't get messages out of order, and no recursion */
 347         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 348                 struct netdev_queue *txq;
 349
 350                 txq = netdev_pick_tx(dev, skb, NULL);
 351
 352                 /* try until next clock tick */
 353                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 354                      tries > 0; --tries) {
 355                         if (HARD_TX_TRYLOCK(dev, txq)) {
 356                                 if (!netif_xmit_stopped(txq))
 357                                         status = netpoll_start_xmit(skb, dev, txq);
 358
 359                                 HARD_TX_UNLOCK(dev, txq);
 360
 361                                 if (dev_xmit_complete(status))
 362                                         break;
 363
 364                         }
 365
 366                         /* tickle device maybe there is some cleanup */
 367                         netpoll_poll_dev(np->dev);
 368
 369                         udelay(USEC_PER_POLL);
 370                 }
 371
 372                 WARN_ONCE(!irqs_disabled(),
 373                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 374                         dev->name, dev->netdev_ops->ndo_start_xmit);
 375
 376         }
 377
 378         if (!dev_xmit_complete(status)) {
 379                 skb_queue_tail(&npinfo->txq, skb);
 380                 schedule_delayed_work(&npinfo->tx_work,0);
 381         }
 382 }
 383 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 384
 385 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 386 {
 387         int total_len, ip_len, udp_len;
 388         struct sk_buff *skb;
 389         struct udphdr *udph;
 390         struct iphdr *iph;
 391         struct ethhdr *eth;
 392         static atomic_t ip_ident;
 393         struct ipv6hdr *ip6h;
 394
 395         WARN_ON_ONCE(!irqs_disabled());
 396
 397         udp_len = len + sizeof(*udph);
 398         if (np->ipv6)
 399                 ip_len = udp_len + sizeof(*ip6h);
 400         else
 401                 ip_len = udp_len + sizeof(*iph);
 402
 403         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 404
 405         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 406                        total_len - len);
 407         if (!skb)
 408                 return;
 409
 410         skb_copy_to_linear_data(skb, msg, len);
 411         skb_put(skb, len);
 412
 413         skb_push(skb, sizeof(*udph));
 414         skb_reset_transport_header(skb);
 415         udph = udp_hdr(skb);
 416         udph->source = htons(np->local_port);
 417         udph->dest = htons(np->remote_port);
 418         udph->len = htons(udp_len);
 419
 420         if (np->ipv6) {
 421                 udph->check = 0;
 422                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 423                                               &np->remote_ip.in6,
 424                                               udp_len, IPPROTO_UDP,
 425                                               csum_partial(udph, udp_len, 0));
 426                 if (udph->check == 0)
 427                         udph->check = CSUM_MANGLED_0;
 428
 429                 skb_push(skb, sizeof(*ip6h));
 430                 skb_reset_network_header(skb);
 431                 ip6h = ipv6_hdr(skb);
 432
 433                 /* ip6h->version = 6; ip6h->priority = 0; */
 434                 put_unaligned(0x60, (unsigned char *)ip6h);
 435                 ip6h->flow_lbl[0] = 0;
 436                 ip6h->flow_lbl[1] = 0;
 437                 ip6h->flow_lbl[2] = 0;
 438
 439                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 440                 ip6h->nexthdr = IPPROTO_UDP;
 441                 ip6h->hop_limit = 32;
 442                 ip6h->saddr = np->local_ip.in6;
 443                 ip6h->daddr = np->remote_ip.in6;
 444
 445                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 446                 skb_reset_mac_header(skb);
 447                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 448         } else {
 449                 udph->check = 0;
 450                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 451                                                 np->remote_ip.ip,
 452                                                 udp_len, IPPROTO_UDP,
 453                                                 csum_partial(udph, udp_len, 0));
 454                 if (udph->check == 0)
 455                         udph->check = CSUM_MANGLED_0;
 456
 457                 skb_push(skb, sizeof(*iph));
 458                 skb_reset_network_header(skb);
 459                 iph = ip_hdr(skb);
 460
 461                 /* iph->version = 4; iph->ihl = 5; */
 462                 put_unaligned(0x45, (unsigned char *)iph);
 463                 iph->tos      = 0;
 464                 put_unaligned(htons(ip_len), &(iph->tot_len));
 465                 iph->id       = htons(atomic_inc_return(&ip_ident));
 466                 iph->frag_off = 0;
 467                 iph->ttl      = 64;
 468                 iph->protocol = IPPROTO_UDP;
 469                 iph->check    = 0;
 470                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 471                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 472                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 473
 474                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 475                 skb_reset_mac_header(skb);
 476                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 477         }
 478
 479         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 480         ether_addr_copy(eth->h_dest, np->remote_mac);
 481
 482         skb->dev = np->dev;
 483
 484         netpoll_send_skb(np, skb);
 485 }
 486 EXPORT_SYMBOL(netpoll_send_udp);
 487
 488 void netpoll_print_options(struct netpoll *np)
 489 {
 490         np_info(np, "local port %d\n", np->local_port);
 491         if (np->ipv6)
 492                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 493         else
 494                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 495         np_info(np, "interface '%s'\n", np->dev_name);
 496         np_info(np, "remote port %d\n", np->remote_port);
 497         if (np->ipv6)
 498                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 499         else
 500                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 501         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 502 }
 503 EXPORT_SYMBOL(netpoll_print_options);
 504
 505 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 506 {
 507         const char *end;
 508
 509         if (!strchr(str, ':') &&
 510             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 511                 if (!*end)
 512                         return 0;
 513         }
 514         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 515 #if IS_ENABLED(CONFIG_IPV6)
 516                 if (!*end)
 517                         return 1;
 518 #else
 519                 return -1;
 520 #endif
 521         }
 522         return -1;
 523 }
 524
 525 int netpoll_parse_options(struct netpoll *np, char *opt)
 526 {
 527         char *cur=opt, *delim;
 528         int ipv6;
 529         bool ipversion_set = false;
 530
 531         if (*cur != '@') {
 532                 if ((delim = strchr(cur, '@')) == NULL)
 533                         goto parse_failed;
 534                 *delim = 0;
 535                 if (kstrtou16(cur, 10, &np->local_port))
 536                         goto parse_failed;
 537                 cur = delim;
 538         }
 539         cur++;
 540
 541         if (*cur != '/') {
 542                 ipversion_set = true;
 543                 if ((delim = strchr(cur, '/')) == NULL)
 544                         goto parse_failed;
 545                 *delim = 0;
 546                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 547                 if (ipv6 < 0)
 548                         goto parse_failed;
 549                 else
 550                         np->ipv6 = (bool)ipv6;
 551                 cur = delim;
 552         }
 553         cur++;
 554
 555         if (*cur != ',') {
 556                 /* parse out dev name */
 557                 if ((delim = strchr(cur, ',')) == NULL)
 558                         goto parse_failed;
 559                 *delim = 0;
 560                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 561                 cur = delim;
 562         }
 563         cur++;
 564
 565         if (*cur != '@') {
 566                 /* dst port */
 567                 if ((delim = strchr(cur, '@')) == NULL)
 568                         goto parse_failed;
 569                 *delim = 0;
 570                 if (*cur == ' ' || *cur == '\t')
 571                         np_info(np, "warning: whitespace is not allowed\n");
 572                 if (kstrtou16(cur, 10, &np->remote_port))
 573                         goto parse_failed;
 574                 cur = delim;
 575         }
 576         cur++;
 577
 578         /* dst ip */
 579         if ((delim = strchr(cur, '/')) == NULL)
 580                 goto parse_failed;
 581         *delim = 0;
 582         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 583         if (ipv6 < 0)
 584                 goto parse_failed;
 585         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 586                 goto parse_failed;
 587         else
 588                 np->ipv6 = (bool)ipv6;
 589         cur = delim + 1;
 590
 591         if (*cur != 0) {
 592                 /* MAC address */
 593                 if (!mac_pton(cur, np->remote_mac))
 594                         goto parse_failed;
 595         }
 596
 597         netpoll_print_options(np);
 598
 599         return 0;
 600
 601  parse_failed:
 602         np_info(np, "couldn't parse config at '%s'!\n", cur);
 603         return -1;
 604 }
 605 EXPORT_SYMBOL(netpoll_parse_options);
 606
 607 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 608 {
 609         struct netpoll_info *npinfo;
 610         const struct net_device_ops *ops;
 611         int err;
 612
 613         np->dev = ndev;
 614         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 615         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
 616
 617         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 618             !ndev->netdev_ops->ndo_poll_controller) {
 619                 np_err(np, "%s doesn't support polling, aborting\n",
 620                        np->dev_name);
 621                 err = -ENOTSUPP;
 622                 goto out;
 623         }
 624
 625         if (!ndev->npinfo) {
 626                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 627                 if (!npinfo) {
 628                         err = -ENOMEM;
 629                         goto out;
 630                 }
 631
 632                 sema_init(&npinfo->dev_lock, 1);
 633                 skb_queue_head_init(&npinfo->txq);
 634                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 635
 636                 atomic_set(&npinfo->refcnt, 1);
 637
 638                 ops = np->dev->netdev_ops;
 639                 if (ops->ndo_netpoll_setup) {
 640                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 641                         if (err)
 642                                 goto free_npinfo;
 643                 }
 644         } else {
 645                 npinfo = rtnl_dereference(ndev->npinfo);
 646                 atomic_inc(&npinfo->refcnt);
 647         }
 648
 649         npinfo->netpoll = np;
 650
 651         /* last thing to do is link it to the net device structure */
 652         rcu_assign_pointer(ndev->npinfo, npinfo);
 653
 654         return 0;
 655
 656 free_npinfo:
 657         kfree(npinfo);
 658 out:
 659         return err;
 660 }
 661 EXPORT_SYMBOL_GPL(__netpoll_setup);
 662
 663 int netpoll_setup(struct netpoll *np)
 664 {
 665         struct net_device *ndev = NULL, *dev = NULL;
 666         struct net *net = current->nsproxy->net_ns;
 667         struct in_device *in_dev;
 668         int err;
 669
 670         rtnl_lock();
 671         if (np->dev_name[0])
 672                 ndev = __dev_get_by_name(net, np->dev_name);
 673
 674         if (!ndev) {
 675                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 676                 err = -ENODEV;
 677                 goto unlock;
 678         }
 679         dev_hold(ndev);
 680
 681         /* bring up DSA management network devices up first */
 682         for_each_netdev(net, dev) {
 683                 if (!netdev_uses_dsa(dev))
 684                         continue;
 685
 686                 err = dev_change_flags(dev, dev->flags | IFF_UP);
 687                 if (err < 0) {
 688                         np_err(np, "%s failed to open %s\n",
 689                                np->dev_name, dev->name);
 690                         goto put;
 691                 }
 692         }
 693
 694         if (netdev_master_upper_dev_get(ndev)) {
 695                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 696                 err = -EBUSY;
 697                 goto put;
 698         }
 699
 700         if (!netif_running(ndev)) {
 701                 unsigned long atmost, atleast;
 702
 703                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 704
 705                 err = dev_open(ndev);
 706
 707                 if (err) {
 708                         np_err(np, "failed to open %s\n", ndev->name);
 709                         goto put;
 710                 }
 711
 712                 rtnl_unlock();
 713                 atleast = jiffies + HZ/10;
 714                 atmost = jiffies + carrier_timeout * HZ;
 715                 while (!netif_carrier_ok(ndev)) {
 716                         if (time_after(jiffies, atmost)) {
 717                                 np_notice(np, "timeout waiting for carrier\n");
 718                                 break;
 719                         }
 720                         msleep(1);
 721                 }
 722
 723                 /* If carrier appears to come up instantly, we don't
 724                  * trust it and pause so that we don't pump all our
 725                  * queued console messages into the bitbucket.
 726                  */
 727
 728                 if (time_before(jiffies, atleast)) {
 729                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 730                         msleep(4000);
 731                 }
 732                 rtnl_lock();
 733         }
 734
 735         if (!np->local_ip.ip) {
 736                 if (!np->ipv6) {
 737                         in_dev = __in_dev_get_rtnl(ndev);
 738
 739                         if (!in_dev || !in_dev->ifa_list) {
 740                                 np_err(np, "no IP address for %s, aborting\n",
 741                                        np->dev_name);
 742                                 err = -EDESTADDRREQ;
 743                                 goto put;
 744                         }
 745
 746                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
 747                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 748                 } else {
 749 #if IS_ENABLED(CONFIG_IPV6)
 750                         struct inet6_dev *idev;
 751
 752                         err = -EDESTADDRREQ;
 753                         idev = __in6_dev_get(ndev);
 754                         if (idev) {
 755                                 struct inet6_ifaddr *ifp;
 756
 757                                 read_lock_bh(&idev->lock);
 758                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 759                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
 760                                                 continue;
 761                                         np->local_ip.in6 = ifp->addr;
 762                                         err = 0;
 763                                         break;
 764                                 }
 765                                 read_unlock_bh(&idev->lock);
 766                         }
 767                         if (err) {
 768                                 np_err(np, "no IPv6 address for %s, aborting\n",
 769                                        np->dev_name);
 770                                 goto put;
 771                         } else
 772                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 773 #else
 774                         np_err(np, "IPv6 is not supported %s, aborting\n",
 775                                np->dev_name);
 776                         err = -EINVAL;
 777                         goto put;
 778 #endif
 779                 }
 780         }
 781
 782         /* fill up the skb queue */
 783         refill_skbs();
 784
 785         err = __netpoll_setup(np, ndev);
 786         if (err)
 787                 goto put;
 788
 789         rtnl_unlock();
 790         return 0;
 791
 792 put:
 793         dev_put(ndev);
 794 unlock:
 795         rtnl_unlock();
 796         return err;
 797 }
 798 EXPORT_SYMBOL(netpoll_setup);
 799
 800 static int __init netpoll_init(void)
 801 {
 802         skb_queue_head_init(&skb_pool);
 803         return 0;
 804 }
 805 core_initcall(netpoll_init);
 806
 807 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 808 {
 809         struct netpoll_info *npinfo =
 810                         container_of(rcu_head, struct netpoll_info, rcu);
 811
 812         skb_queue_purge(&npinfo->txq);
 813
 814         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 815         cancel_delayed_work(&npinfo->tx_work);
 816
 817         /* clean after last, unfinished work */
 818         __skb_queue_purge(&npinfo->txq);
 819         /* now cancel it again */
 820         cancel_delayed_work(&npinfo->tx_work);
 821         kfree(npinfo);
 822 }
 823
 824 void __netpoll_cleanup(struct netpoll *np)
 825 {
 826         struct netpoll_info *npinfo;
 827
 828         /* rtnl_dereference would be preferable here but
 829          * rcu_cleanup_netpoll path can put us in here safely without
 830          * holding the rtnl, so plain rcu_dereference it is
 831          */
 832         npinfo = rtnl_dereference(np->dev->npinfo);
 833         if (!npinfo)
 834                 return;
 835
 836         synchronize_srcu(&netpoll_srcu);
 837
 838         if (atomic_dec_and_test(&npinfo->refcnt)) {
 839                 const struct net_device_ops *ops;
 840
 841                 ops = np->dev->netdev_ops;
 842                 if (ops->ndo_netpoll_cleanup)
 843                         ops->ndo_netpoll_cleanup(np->dev);
 844
 845                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 846                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
 847         } else
 848                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 849 }
 850 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 851
 852 static void netpoll_async_cleanup(struct work_struct *work)
 853 {
 854         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
 855
 856         rtnl_lock();
 857         __netpoll_cleanup(np);
 858         rtnl_unlock();
 859         kfree(np);
 860 }
 861
 862 void __netpoll_free_async(struct netpoll *np)
 863 {
 864         schedule_work(&np->cleanup_work);
 865 }
 866 EXPORT_SYMBOL_GPL(__netpoll_free_async);
 867
 868 void netpoll_cleanup(struct netpoll *np)
 869 {
 870         rtnl_lock();
 871         if (!np->dev)
 872                 goto out;
 873         __netpoll_cleanup(np);
 874         dev_put(np->dev);
 875         np->dev = NULL;
 876 out:
 877         rtnl_unlock();
 878 }
 879 EXPORT_SYMBOL(netpoll_cleanup);