net/core/netpoll.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Common framework for low-level network console, dump, and debugger code
   4  *
   5  * Sep 8 2003  Matt Mackall <[email protected]>
   6  *
   7  * based on the netconsole code from:
   8  *
   9  * Copyright (C) 2001  Ingo Molnar <[email protected]>
  10  * Copyright (C) 2002  Red Hat, Inc.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/moduleparam.h>
  16 #include <linux/kernel.h>
  17 #include <linux/netdevice.h>
  18 #include <linux/etherdevice.h>
  19 #include <linux/string.h>
  20 #include <linux/if_arp.h>
  21 #include <linux/inetdevice.h>
  22 #include <linux/inet.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/netpoll.h>
  25 #include <linux/sched.h>
  26 #include <linux/delay.h>
  27 #include <linux/rcupdate.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/slab.h>
  30 #include <linux/export.h>
  31 #include <linux/if_vlan.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
  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 netdev_tx_t netpoll_start_xmit(struct sk_buff *skb,
  73                                       struct net_device *dev,
  74                                       struct netdev_queue *txq)
  75 {
  76         netdev_tx_t 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 static void poll_one_napi(struct napi_struct *napi)
 140 {
 141         int work;
 142
 143         /* If we set this bit but see that it has already been set,
 144          * that indicates that napi has been disabled and we need
 145          * to abort this operation
 146          */
 147         if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
 148                 return;
 149
 150         /* We explicilty pass the polling call a budget of 0 to
 151          * indicate that we are clearing the Tx path only.
 152          */
 153         work = napi->poll(napi, 0);
 154         WARN_ONCE(work, "%pS exceeded budget in poll\n", napi->poll);
 155         trace_napi_poll(napi, work, 0);
 156
 157         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 158 }
 159
 160 static void poll_napi(struct net_device *dev)
 161 {
 162         struct napi_struct *napi;
 163         int cpu = smp_processor_id();
 164
 165         list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
 166                 if (cmpxchg(&napi->poll_owner, -1, cpu) == -1) {
 167                         poll_one_napi(napi);
 168                         smp_store_release(&napi->poll_owner, -1);
 169                 }
 170         }
 171 }
 172
 173 void netpoll_poll_dev(struct net_device *dev)
 174 {
 175         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 176         const struct net_device_ops *ops;
 177
 178         /* Don't do any rx activity if the dev_lock mutex is held
 179          * the dev_open/close paths use this to block netpoll activity
 180          * while changing device state
 181          */
 182         if (!ni || down_trylock(&ni->dev_lock))
 183                 return;
 184
 185         if (!netif_running(dev)) {
 186                 up(&ni->dev_lock);
 187                 return;
 188         }
 189
 190         ops = dev->netdev_ops;
 191         if (ops->ndo_poll_controller)
 192                 ops->ndo_poll_controller(dev);
 193
 194         poll_napi(dev);
 195
 196         up(&ni->dev_lock);
 197
 198         zap_completion_queue();
 199 }
 200 EXPORT_SYMBOL(netpoll_poll_dev);
 201
 202 void netpoll_poll_disable(struct net_device *dev)
 203 {
 204         struct netpoll_info *ni;
 205         int idx;
 206         might_sleep();
 207         idx = srcu_read_lock(&netpoll_srcu);
 208         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 209         if (ni)
 210                 down(&ni->dev_lock);
 211         srcu_read_unlock(&netpoll_srcu, idx);
 212 }
 213 EXPORT_SYMBOL(netpoll_poll_disable);
 214
 215 void netpoll_poll_enable(struct net_device *dev)
 216 {
 217         struct netpoll_info *ni;
 218         rcu_read_lock();
 219         ni = rcu_dereference(dev->npinfo);
 220         if (ni)
 221                 up(&ni->dev_lock);
 222         rcu_read_unlock();
 223 }
 224 EXPORT_SYMBOL(netpoll_poll_enable);
 225
 226 static void refill_skbs(void)
 227 {
 228         struct sk_buff *skb;
 229         unsigned long flags;
 230
 231         spin_lock_irqsave(&skb_pool.lock, flags);
 232         while (skb_pool.qlen < MAX_SKBS) {
 233                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 234                 if (!skb)
 235                         break;
 236
 237                 __skb_queue_tail(&skb_pool, skb);
 238         }
 239         spin_unlock_irqrestore(&skb_pool.lock, flags);
 240 }
 241
 242 static void zap_completion_queue(void)
 243 {
 244         unsigned long flags;
 245         struct softnet_data *sd = &get_cpu_var(softnet_data);
 246
 247         if (sd->completion_queue) {
 248                 struct sk_buff *clist;
 249
 250                 local_irq_save(flags);
 251                 clist = sd->completion_queue;
 252                 sd->completion_queue = NULL;
 253                 local_irq_restore(flags);
 254
 255                 while (clist != NULL) {
 256                         struct sk_buff *skb = clist;
 257                         clist = clist->next;
 258                         if (!skb_irq_freeable(skb)) {
 259                                 refcount_set(&skb->users, 1);
 260                                 dev_kfree_skb_any(skb); /* put this one back */
 261                         } else {
 262                                 __kfree_skb(skb);
 263                         }
 264                 }
 265         }
 266
 267         put_cpu_var(softnet_data);
 268 }
 269
 270 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 271 {
 272         int count = 0;
 273         struct sk_buff *skb;
 274
 275         zap_completion_queue();
 276         refill_skbs();
 277 repeat:
 278
 279         skb = alloc_skb(len, GFP_ATOMIC);
 280         if (!skb)
 281                 skb = skb_dequeue(&skb_pool);
 282
 283         if (!skb) {
 284                 if (++count < 10) {
 285                         netpoll_poll_dev(np->dev);
 286                         goto repeat;
 287                 }
 288                 return NULL;
 289         }
 290
 291         refcount_set(&skb->users, 1);
 292         skb_reserve(skb, reserve);
 293         return skb;
 294 }
 295
 296 static int netpoll_owner_active(struct net_device *dev)
 297 {
 298         struct napi_struct *napi;
 299
 300         list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
 301                 if (napi->poll_owner == smp_processor_id())
 302                         return 1;
 303         }
 304         return 0;
 305 }
 306
 307 /* call with IRQ disabled */
 308 static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 309 {
 310         netdev_tx_t status = NETDEV_TX_BUSY;
 311         struct net_device *dev;
 312         unsigned long tries;
 313         /* It is up to the caller to keep npinfo alive. */
 314         struct netpoll_info *npinfo;
 315
 316         lockdep_assert_irqs_disabled();
 317
 318         dev = np->dev;
 319         npinfo = rcu_dereference_bh(dev->npinfo);
 320
 321         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 322                 dev_kfree_skb_irq(skb);
 323                 return NET_XMIT_DROP;
 324         }
 325
 326         /* don't get messages out of order, and no recursion */
 327         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 328                 struct netdev_queue *txq;
 329
 330                 txq = netdev_core_pick_tx(dev, skb, NULL);
 331
 332                 /* try until next clock tick */
 333                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 334                      tries > 0; --tries) {
 335                         if (HARD_TX_TRYLOCK(dev, txq)) {
 336                                 if (!netif_xmit_stopped(txq))
 337                                         status = netpoll_start_xmit(skb, dev, txq);
 338
 339                                 HARD_TX_UNLOCK(dev, txq);
 340
 341                                 if (dev_xmit_complete(status))
 342                                         break;
 343
 344                         }
 345
 346                         /* tickle device maybe there is some cleanup */
 347                         netpoll_poll_dev(np->dev);
 348
 349                         udelay(USEC_PER_POLL);
 350                 }
 351
 352                 WARN_ONCE(!irqs_disabled(),
 353                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pS)\n",
 354                         dev->name, dev->netdev_ops->ndo_start_xmit);
 355
 356         }
 357
 358         if (!dev_xmit_complete(status)) {
 359                 skb_queue_tail(&npinfo->txq, skb);
 360                 schedule_delayed_work(&npinfo->tx_work,0);
 361         }
 362         return NETDEV_TX_OK;
 363 }
 364
 365 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 366 {
 367         unsigned long flags;
 368         netdev_tx_t ret;
 369
 370         if (unlikely(!np)) {
 371                 dev_kfree_skb_irq(skb);
 372                 ret = NET_XMIT_DROP;
 373         } else {
 374                 local_irq_save(flags);
 375                 ret = __netpoll_send_skb(np, skb);
 376                 local_irq_restore(flags);
 377         }
 378         return ret;
 379 }
 380 EXPORT_SYMBOL(netpoll_send_skb);
 381
 382 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 383 {
 384         int total_len, ip_len, udp_len;
 385         struct sk_buff *skb;
 386         struct udphdr *udph;
 387         struct iphdr *iph;
 388         struct ethhdr *eth;
 389         static atomic_t ip_ident;
 390         struct ipv6hdr *ip6h;
 391
 392         WARN_ON_ONCE(!irqs_disabled());
 393
 394         udp_len = len + sizeof(*udph);
 395         if (np->ipv6)
 396                 ip_len = udp_len + sizeof(*ip6h);
 397         else
 398                 ip_len = udp_len + sizeof(*iph);
 399
 400         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 401
 402         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 403                        total_len - len);
 404         if (!skb)
 405                 return;
 406
 407         skb_copy_to_linear_data(skb, msg, len);
 408         skb_put(skb, len);
 409
 410         skb_push(skb, sizeof(*udph));
 411         skb_reset_transport_header(skb);
 412         udph = udp_hdr(skb);
 413         udph->source = htons(np->local_port);
 414         udph->dest = htons(np->remote_port);
 415         udph->len = htons(udp_len);
 416
 417         if (np->ipv6) {
 418                 udph->check = 0;
 419                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 420                                               &np->remote_ip.in6,
 421                                               udp_len, IPPROTO_UDP,
 422                                               csum_partial(udph, udp_len, 0));
 423                 if (udph->check == 0)
 424                         udph->check = CSUM_MANGLED_0;
 425
 426                 skb_push(skb, sizeof(*ip6h));
 427                 skb_reset_network_header(skb);
 428                 ip6h = ipv6_hdr(skb);
 429
 430                 /* ip6h->version = 6; ip6h->priority = 0; */
 431                 put_unaligned(0x60, (unsigned char *)ip6h);
 432                 ip6h->flow_lbl[0] = 0;
 433                 ip6h->flow_lbl[1] = 0;
 434                 ip6h->flow_lbl[2] = 0;
 435
 436                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 437                 ip6h->nexthdr = IPPROTO_UDP;
 438                 ip6h->hop_limit = 32;
 439                 ip6h->saddr = np->local_ip.in6;
 440                 ip6h->daddr = np->remote_ip.in6;
 441
 442                 eth = skb_push(skb, ETH_HLEN);
 443                 skb_reset_mac_header(skb);
 444                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 445         } else {
 446                 udph->check = 0;
 447                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 448                                                 np->remote_ip.ip,
 449                                                 udp_len, IPPROTO_UDP,
 450                                                 csum_partial(udph, udp_len, 0));
 451                 if (udph->check == 0)
 452                         udph->check = CSUM_MANGLED_0;
 453
 454                 skb_push(skb, sizeof(*iph));
 455                 skb_reset_network_header(skb);
 456                 iph = ip_hdr(skb);
 457
 458                 /* iph->version = 4; iph->ihl = 5; */
 459                 put_unaligned(0x45, (unsigned char *)iph);
 460                 iph->tos      = 0;
 461                 put_unaligned(htons(ip_len), &(iph->tot_len));
 462                 iph->id       = htons(atomic_inc_return(&ip_ident));
 463                 iph->frag_off = 0;
 464                 iph->ttl      = 64;
 465                 iph->protocol = IPPROTO_UDP;
 466                 iph->check    = 0;
 467                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 468                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 469                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 470
 471                 eth = skb_push(skb, ETH_HLEN);
 472                 skb_reset_mac_header(skb);
 473                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 474         }
 475
 476         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 477         ether_addr_copy(eth->h_dest, np->remote_mac);
 478
 479         skb->dev = np->dev;
 480
 481         netpoll_send_skb(np, skb);
 482 }
 483 EXPORT_SYMBOL(netpoll_send_udp);
 484
 485 void netpoll_print_options(struct netpoll *np)
 486 {
 487         np_info(np, "local port %d\n", np->local_port);
 488         if (np->ipv6)
 489                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 490         else
 491                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 492         np_info(np, "interface '%s'\n", np->dev_name);
 493         np_info(np, "remote port %d\n", np->remote_port);
 494         if (np->ipv6)
 495                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 496         else
 497                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 498         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 499 }
 500 EXPORT_SYMBOL(netpoll_print_options);
 501
 502 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 503 {
 504         const char *end;
 505
 506         if (!strchr(str, ':') &&
 507             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 508                 if (!*end)
 509                         return 0;
 510         }
 511         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 512 #if IS_ENABLED(CONFIG_IPV6)
 513                 if (!*end)
 514                         return 1;
 515 #else
 516                 return -1;
 517 #endif
 518         }
 519         return -1;
 520 }
 521
 522 int netpoll_parse_options(struct netpoll *np, char *opt)
 523 {
 524         char *cur=opt, *delim;
 525         int ipv6;
 526         bool ipversion_set = false;
 527
 528         if (*cur != '@') {
 529                 if ((delim = strchr(cur, '@')) == NULL)
 530                         goto parse_failed;
 531                 *delim = 0;
 532                 if (kstrtou16(cur, 10, &np->local_port))
 533                         goto parse_failed;
 534                 cur = delim;
 535         }
 536         cur++;
 537
 538         if (*cur != '/') {
 539                 ipversion_set = true;
 540                 if ((delim = strchr(cur, '/')) == NULL)
 541                         goto parse_failed;
 542                 *delim = 0;
 543                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 544                 if (ipv6 < 0)
 545                         goto parse_failed;
 546                 else
 547                         np->ipv6 = (bool)ipv6;
 548                 cur = delim;
 549         }
 550         cur++;
 551
 552         if (*cur != ',') {
 553                 /* parse out dev name */
 554                 if ((delim = strchr(cur, ',')) == NULL)
 555                         goto parse_failed;
 556                 *delim = 0;
 557                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 558                 cur = delim;
 559         }
 560         cur++;
 561
 562         if (*cur != '@') {
 563                 /* dst port */
 564                 if ((delim = strchr(cur, '@')) == NULL)
 565                         goto parse_failed;
 566                 *delim = 0;
 567                 if (*cur == ' ' || *cur == '\t')
 568                         np_info(np, "warning: whitespace is not allowed\n");
 569                 if (kstrtou16(cur, 10, &np->remote_port))
 570                         goto parse_failed;
 571                 cur = delim;
 572         }
 573         cur++;
 574
 575         /* dst ip */
 576         if ((delim = strchr(cur, '/')) == NULL)
 577                 goto parse_failed;
 578         *delim = 0;
 579         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 580         if (ipv6 < 0)
 581                 goto parse_failed;
 582         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 583                 goto parse_failed;
 584         else
 585                 np->ipv6 = (bool)ipv6;
 586         cur = delim + 1;
 587
 588         if (*cur != 0) {
 589                 /* MAC address */
 590                 if (!mac_pton(cur, np->remote_mac))
 591                         goto parse_failed;
 592         }
 593
 594         netpoll_print_options(np);
 595
 596         return 0;
 597
 598  parse_failed:
 599         np_info(np, "couldn't parse config at '%s'!\n", cur);
 600         return -1;
 601 }
 602 EXPORT_SYMBOL(netpoll_parse_options);
 603
 604 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 605 {
 606         struct netpoll_info *npinfo;
 607         const struct net_device_ops *ops;
 608         int err;
 609
 610         np->dev = ndev;
 611         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 612
 613         if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {
 614                 np_err(np, "%s doesn't support polling, aborting\n",
 615                        np->dev_name);
 616                 err = -ENOTSUPP;
 617                 goto out;
 618         }
 619
 620         if (!ndev->npinfo) {
 621                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 622                 if (!npinfo) {
 623                         err = -ENOMEM;
 624                         goto out;
 625                 }
 626
 627                 sema_init(&npinfo->dev_lock, 1);
 628                 skb_queue_head_init(&npinfo->txq);
 629                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 630
 631                 refcount_set(&npinfo->refcnt, 1);
 632
 633                 ops = np->dev->netdev_ops;
 634                 if (ops->ndo_netpoll_setup) {
 635                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 636                         if (err)
 637                                 goto free_npinfo;
 638                 }
 639         } else {
 640                 npinfo = rtnl_dereference(ndev->npinfo);
 641                 refcount_inc(&npinfo->refcnt);
 642         }
 643
 644         npinfo->netpoll = np;
 645
 646         /* last thing to do is link it to the net device structure */
 647         rcu_assign_pointer(ndev->npinfo, npinfo);
 648
 649         return 0;
 650
 651 free_npinfo:
 652         kfree(npinfo);
 653 out:
 654         return err;
 655 }
 656 EXPORT_SYMBOL_GPL(__netpoll_setup);
 657
 658 int netpoll_setup(struct netpoll *np)
 659 {
 660         struct net_device *ndev = NULL;
 661         struct in_device *in_dev;
 662         int err;
 663
 664         rtnl_lock();
 665         if (np->dev_name[0]) {
 666                 struct net *net = current->nsproxy->net_ns;
 667                 ndev = __dev_get_by_name(net, np->dev_name);
 668         }
 669         if (!ndev) {
 670                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 671                 err = -ENODEV;
 672                 goto unlock;
 673         }
 674         dev_hold(ndev);
 675
 676         if (netdev_master_upper_dev_get(ndev)) {
 677                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 678                 err = -EBUSY;
 679                 goto put;
 680         }
 681
 682         if (!netif_running(ndev)) {
 683                 unsigned long atmost, atleast;
 684
 685                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 686
 687                 err = dev_open(ndev, NULL);
 688
 689                 if (err) {
 690                         np_err(np, "failed to open %s\n", ndev->name);
 691                         goto put;
 692                 }
 693
 694                 rtnl_unlock();
 695                 atleast = jiffies + HZ/10;
 696                 atmost = jiffies + carrier_timeout * HZ;
 697                 while (!netif_carrier_ok(ndev)) {
 698                         if (time_after(jiffies, atmost)) {
 699                                 np_notice(np, "timeout waiting for carrier\n");
 700                                 break;
 701                         }
 702                         msleep(1);
 703                 }
 704
 705                 /* If carrier appears to come up instantly, we don't
 706                  * trust it and pause so that we don't pump all our
 707                  * queued console messages into the bitbucket.
 708                  */
 709
 710                 if (time_before(jiffies, atleast)) {
 711                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 712                         msleep(4000);
 713                 }
 714                 rtnl_lock();
 715         }
 716
 717         if (!np->local_ip.ip) {
 718                 if (!np->ipv6) {
 719                         const struct in_ifaddr *ifa;
 720
 721                         in_dev = __in_dev_get_rtnl(ndev);
 722                         if (!in_dev)
 723                                 goto put_noaddr;
 724
 725                         ifa = rtnl_dereference(in_dev->ifa_list);
 726                         if (!ifa) {
 727 put_noaddr:
 728                                 np_err(np, "no IP address for %s, aborting\n",
 729                                        np->dev_name);
 730                                 err = -EDESTADDRREQ;
 731                                 goto put;
 732                         }
 733
 734                         np->local_ip.ip = ifa->ifa_local;
 735                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 736                 } else {
 737 #if IS_ENABLED(CONFIG_IPV6)
 738                         struct inet6_dev *idev;
 739
 740                         err = -EDESTADDRREQ;
 741                         idev = __in6_dev_get(ndev);
 742                         if (idev) {
 743                                 struct inet6_ifaddr *ifp;
 744
 745                                 read_lock_bh(&idev->lock);
 746                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 747                                         if (!!(ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL) !=
 748                                             !!(ipv6_addr_type(&np->remote_ip.in6) & IPV6_ADDR_LINKLOCAL))
 749                                                 continue;
 750                                         np->local_ip.in6 = ifp->addr;
 751                                         err = 0;
 752                                         break;
 753                                 }
 754                                 read_unlock_bh(&idev->lock);
 755                         }
 756                         if (err) {
 757                                 np_err(np, "no IPv6 address for %s, aborting\n",
 758                                        np->dev_name);
 759                                 goto put;
 760                         } else
 761                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 762 #else
 763                         np_err(np, "IPv6 is not supported %s, aborting\n",
 764                                np->dev_name);
 765                         err = -EINVAL;
 766                         goto put;
 767 #endif
 768                 }
 769         }
 770
 771         /* fill up the skb queue */
 772         refill_skbs();
 773
 774         err = __netpoll_setup(np, ndev);
 775         if (err)
 776                 goto put;
 777
 778         rtnl_unlock();
 779         return 0;
 780
 781 put:
 782         dev_put(ndev);
 783 unlock:
 784         rtnl_unlock();
 785         return err;
 786 }
 787 EXPORT_SYMBOL(netpoll_setup);
 788
 789 static int __init netpoll_init(void)
 790 {
 791         skb_queue_head_init(&skb_pool);
 792         return 0;
 793 }
 794 core_initcall(netpoll_init);
 795
 796 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 797 {
 798         struct netpoll_info *npinfo =
 799                         container_of(rcu_head, struct netpoll_info, rcu);
 800
 801         skb_queue_purge(&npinfo->txq);
 802
 803         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 804         cancel_delayed_work(&npinfo->tx_work);
 805
 806         /* clean after last, unfinished work */
 807         __skb_queue_purge(&npinfo->txq);
 808         /* now cancel it again */
 809         cancel_delayed_work(&npinfo->tx_work);
 810         kfree(npinfo);
 811 }
 812
 813 void __netpoll_cleanup(struct netpoll *np)
 814 {
 815         struct netpoll_info *npinfo;
 816
 817         npinfo = rtnl_dereference(np->dev->npinfo);
 818         if (!npinfo)
 819                 return;
 820
 821         synchronize_srcu(&netpoll_srcu);
 822
 823         if (refcount_dec_and_test(&npinfo->refcnt)) {
 824                 const struct net_device_ops *ops;
 825
 826                 ops = np->dev->netdev_ops;
 827                 if (ops->ndo_netpoll_cleanup)
 828                         ops->ndo_netpoll_cleanup(np->dev);
 829
 830                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 831                 call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info);
 832         } else
 833                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 834 }
 835 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 836
 837 void __netpoll_free(struct netpoll *np)
 838 {
 839         ASSERT_RTNL();
 840
 841         /* Wait for transmitting packets to finish before freeing. */
 842         synchronize_rcu();
 843         __netpoll_cleanup(np);
 844         kfree(np);
 845 }
 846 EXPORT_SYMBOL_GPL(__netpoll_free);
 847
 848 void netpoll_cleanup(struct netpoll *np)
 849 {
 850         rtnl_lock();
 851         if (!np->dev)
 852                 goto out;
 853         __netpoll_cleanup(np);
 854         dev_put(np->dev);
 855         np->dev = NULL;
 856 out:
 857         rtnl_unlock();
 858 }
 859 EXPORT_SYMBOL(netpoll_cleanup);