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 <mpm@selenic.com>
   6  *
   7  * based on the netconsole code from:
   8  *
   9  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
  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 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                 unsigned int q_index;
 109
 110                 if (!netif_device_present(dev) || !netif_running(dev)) {
 111                         kfree_skb(skb);
 112                         continue;
 113                 }
 114
 115                 local_irq_save(flags);
 116                 /* check if skb->queue_mapping is still valid */
 117                 q_index = skb_get_queue_mapping(skb);
 118                 if (unlikely(q_index >= dev->real_num_tx_queues)) {
 119                         q_index = q_index % dev->real_num_tx_queues;
 120                         skb_set_queue_mapping(skb, q_index);
 121                 }
 122                 txq = netdev_get_tx_queue(dev, q_index);
 123                 HARD_TX_LOCK(dev, txq, smp_processor_id());
 124                 if (netif_xmit_frozen_or_stopped(txq) ||
 125                     !dev_xmit_complete(netpoll_start_xmit(skb, dev, txq))) {
 126                         skb_queue_head(&npinfo->txq, skb);
 127                         HARD_TX_UNLOCK(dev, txq);
 128                         local_irq_restore(flags);
 129
 130                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 131                         return;
 132                 }
 133                 HARD_TX_UNLOCK(dev, txq);
 134                 local_irq_restore(flags);
 135         }
 136 }
 137
 138 static void poll_one_napi(struct napi_struct *napi)
 139 {
 140         int work;
 141
 142         /* If we set this bit but see that it has already been set,
 143          * that indicates that napi has been disabled and we need
 144          * to abort this operation
 145          */
 146         if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
 147                 return;
 148
 149         /* We explicilty pass the polling call a budget of 0 to
 150          * indicate that we are clearing the Tx path only.
 151          */
 152         work = napi->poll(napi, 0);
 153         WARN_ONCE(work, "%pS exceeded budget in poll\n", napi->poll);
 154         trace_napi_poll(napi, work, 0);
 155
 156         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 157 }
 158
 159 static void poll_napi(struct net_device *dev)
 160 {
 161         struct napi_struct *napi;
 162         int cpu = smp_processor_id();
 163
 164         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 165                 if (cmpxchg(&napi->poll_owner, -1, cpu) == -1) {
 166                         poll_one_napi(napi);
 167                         smp_store_release(&napi->poll_owner, -1);
 168                 }
 169         }
 170 }
 171
 172 void netpoll_poll_dev(struct net_device *dev)
 173 {
 174         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 175         const struct net_device_ops *ops;
 176
 177         /* Don't do any rx activity if the dev_lock mutex is held
 178          * the dev_open/close paths use this to block netpoll activity
 179          * while changing device state
 180          */
 181         if (!ni || down_trylock(&ni->dev_lock))
 182                 return;
 183
 184         if (!netif_running(dev)) {
 185                 up(&ni->dev_lock);
 186                 return;
 187         }
 188
 189         ops = dev->netdev_ops;
 190         if (ops->ndo_poll_controller)
 191                 ops->ndo_poll_controller(dev);
 192
 193         poll_napi(dev);
 194
 195         up(&ni->dev_lock);
 196
 197         zap_completion_queue();
 198 }
 199 EXPORT_SYMBOL(netpoll_poll_dev);
 200
 201 void netpoll_poll_disable(struct net_device *dev)
 202 {
 203         struct netpoll_info *ni;
 204         int idx;
 205         might_sleep();
 206         idx = srcu_read_lock(&netpoll_srcu);
 207         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 208         if (ni)
 209                 down(&ni->dev_lock);
 210         srcu_read_unlock(&netpoll_srcu, idx);
 211 }
 212 EXPORT_SYMBOL(netpoll_poll_disable);
 213
 214 void netpoll_poll_enable(struct net_device *dev)
 215 {
 216         struct netpoll_info *ni;
 217         rcu_read_lock();
 218         ni = rcu_dereference(dev->npinfo);
 219         if (ni)
 220                 up(&ni->dev_lock);
 221         rcu_read_unlock();
 222 }
 223 EXPORT_SYMBOL(netpoll_poll_enable);
 224
 225 static void refill_skbs(void)
 226 {
 227         struct sk_buff *skb;
 228         unsigned long flags;
 229
 230         spin_lock_irqsave(&skb_pool.lock, flags);
 231         while (skb_pool.qlen < MAX_SKBS) {
 232                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 233                 if (!skb)
 234                         break;
 235
 236                 __skb_queue_tail(&skb_pool, skb);
 237         }
 238         spin_unlock_irqrestore(&skb_pool.lock, flags);
 239 }
 240
 241 static void zap_completion_queue(void)
 242 {
 243         unsigned long flags;
 244         struct softnet_data *sd = &get_cpu_var(softnet_data);
 245
 246         if (sd->completion_queue) {
 247                 struct sk_buff *clist;
 248
 249                 local_irq_save(flags);
 250                 clist = sd->completion_queue;
 251                 sd->completion_queue = NULL;
 252                 local_irq_restore(flags);
 253
 254                 while (clist != NULL) {
 255                         struct sk_buff *skb = clist;
 256                         clist = clist->next;
 257                         if (!skb_irq_freeable(skb)) {
 258                                 refcount_set(&skb->users, 1);
 259                                 dev_kfree_skb_any(skb); /* put this one back */
 260                         } else {
 261                                 __kfree_skb(skb);
 262                         }
 263                 }
 264         }
 265
 266         put_cpu_var(softnet_data);
 267 }
 268
 269 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 270 {
 271         int count = 0;
 272         struct sk_buff *skb;
 273
 274         zap_completion_queue();
 275         refill_skbs();
 276 repeat:
 277
 278         skb = alloc_skb(len, GFP_ATOMIC);
 279         if (!skb)
 280                 skb = skb_dequeue(&skb_pool);
 281
 282         if (!skb) {
 283                 if (++count < 10) {
 284                         netpoll_poll_dev(np->dev);
 285                         goto repeat;
 286                 }
 287                 return NULL;
 288         }
 289
 290         refcount_set(&skb->users, 1);
 291         skb_reserve(skb, reserve);
 292         return skb;
 293 }
 294
 295 static int netpoll_owner_active(struct net_device *dev)
 296 {
 297         struct napi_struct *napi;
 298
 299         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 300                 if (napi->poll_owner == smp_processor_id())
 301                         return 1;
 302         }
 303         return 0;
 304 }
 305
 306 /* call with IRQ disabled */
 307 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 308                              struct net_device *dev)
 309 {
 310         int status = NETDEV_TX_BUSY;
 311         unsigned long tries;
 312         /* It is up to the caller to keep npinfo alive. */
 313         struct netpoll_info *npinfo;
 314
 315         lockdep_assert_irqs_disabled();
 316
 317         npinfo = rcu_dereference_bh(np->dev->npinfo);
 318         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 319                 dev_kfree_skb_irq(skb);
 320                 return;
 321         }
 322
 323         /* don't get messages out of order, and no recursion */
 324         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 325                 struct netdev_queue *txq;
 326
 327                 txq = netdev_core_pick_tx(dev, skb, NULL);
 328
 329                 /* try until next clock tick */
 330                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 331                      tries > 0; --tries) {
 332                         if (HARD_TX_TRYLOCK(dev, txq)) {
 333                                 if (!netif_xmit_stopped(txq))
 334                                         status = netpoll_start_xmit(skb, dev, txq);
 335
 336                                 HARD_TX_UNLOCK(dev, txq);
 337
 338                                 if (dev_xmit_complete(status))
 339                                         break;
 340
 341                         }
 342
 343                         /* tickle device maybe there is some cleanup */
 344                         netpoll_poll_dev(np->dev);
 345
 346                         udelay(USEC_PER_POLL);
 347                 }
 348
 349                 WARN_ONCE(!irqs_disabled(),
 350                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pS)\n",
 351                         dev->name, dev->netdev_ops->ndo_start_xmit);
 352
 353         }
 354
 355         if (!dev_xmit_complete(status)) {
 356                 skb_queue_tail(&npinfo->txq, skb);
 357                 schedule_delayed_work(&npinfo->tx_work,0);
 358         }
 359 }
 360 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 361
 362 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 363 {
 364         int total_len, ip_len, udp_len;
 365         struct sk_buff *skb;
 366         struct udphdr *udph;
 367         struct iphdr *iph;
 368         struct ethhdr *eth;
 369         static atomic_t ip_ident;
 370         struct ipv6hdr *ip6h;
 371
 372         WARN_ON_ONCE(!irqs_disabled());
 373
 374         udp_len = len + sizeof(*udph);
 375         if (np->ipv6)
 376                 ip_len = udp_len + sizeof(*ip6h);
 377         else
 378                 ip_len = udp_len + sizeof(*iph);
 379
 380         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 381
 382         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 383                        total_len - len);
 384         if (!skb)
 385                 return;
 386
 387         skb_copy_to_linear_data(skb, msg, len);
 388         skb_put(skb, len);
 389
 390         skb_push(skb, sizeof(*udph));
 391         skb_reset_transport_header(skb);
 392         udph = udp_hdr(skb);
 393         udph->source = htons(np->local_port);
 394         udph->dest = htons(np->remote_port);
 395         udph->len = htons(udp_len);
 396
 397         if (np->ipv6) {
 398                 udph->check = 0;
 399                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 400                                               &np->remote_ip.in6,
 401                                               udp_len, IPPROTO_UDP,
 402                                               csum_partial(udph, udp_len, 0));
 403                 if (udph->check == 0)
 404                         udph->check = CSUM_MANGLED_0;
 405
 406                 skb_push(skb, sizeof(*ip6h));
 407                 skb_reset_network_header(skb);
 408                 ip6h = ipv6_hdr(skb);
 409
 410                 /* ip6h->version = 6; ip6h->priority = 0; */
 411                 put_unaligned(0x60, (unsigned char *)ip6h);
 412                 ip6h->flow_lbl[0] = 0;
 413                 ip6h->flow_lbl[1] = 0;
 414                 ip6h->flow_lbl[2] = 0;
 415
 416                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 417                 ip6h->nexthdr = IPPROTO_UDP;
 418                 ip6h->hop_limit = 32;
 419                 ip6h->saddr = np->local_ip.in6;
 420                 ip6h->daddr = np->remote_ip.in6;
 421
 422                 eth = skb_push(skb, ETH_HLEN);
 423                 skb_reset_mac_header(skb);
 424                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 425         } else {
 426                 udph->check = 0;
 427                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 428                                                 np->remote_ip.ip,
 429                                                 udp_len, IPPROTO_UDP,
 430                                                 csum_partial(udph, udp_len, 0));
 431                 if (udph->check == 0)
 432                         udph->check = CSUM_MANGLED_0;
 433
 434                 skb_push(skb, sizeof(*iph));
 435                 skb_reset_network_header(skb);
 436                 iph = ip_hdr(skb);
 437
 438                 /* iph->version = 4; iph->ihl = 5; */
 439                 put_unaligned(0x45, (unsigned char *)iph);
 440                 iph->tos      = 0;
 441                 put_unaligned(htons(ip_len), &(iph->tot_len));
 442                 iph->id       = htons(atomic_inc_return(&ip_ident));
 443                 iph->frag_off = 0;
 444                 iph->ttl      = 64;
 445                 iph->protocol = IPPROTO_UDP;
 446                 iph->check    = 0;
 447                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 448                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 449                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 450
 451                 eth = skb_push(skb, ETH_HLEN);
 452                 skb_reset_mac_header(skb);
 453                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 454         }
 455
 456         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 457         ether_addr_copy(eth->h_dest, np->remote_mac);
 458
 459         skb->dev = np->dev;
 460
 461         netpoll_send_skb(np, skb);
 462 }
 463 EXPORT_SYMBOL(netpoll_send_udp);
 464
 465 void netpoll_print_options(struct netpoll *np)
 466 {
 467         np_info(np, "local port %d\n", np->local_port);
 468         if (np->ipv6)
 469                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 470         else
 471                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 472         np_info(np, "interface '%s'\n", np->dev_name);
 473         np_info(np, "remote port %d\n", np->remote_port);
 474         if (np->ipv6)
 475                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 476         else
 477                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 478         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 479 }
 480 EXPORT_SYMBOL(netpoll_print_options);
 481
 482 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 483 {
 484         const char *end;
 485
 486         if (!strchr(str, ':') &&
 487             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 488                 if (!*end)
 489                         return 0;
 490         }
 491         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 492 #if IS_ENABLED(CONFIG_IPV6)
 493                 if (!*end)
 494                         return 1;
 495 #else
 496                 return -1;
 497 #endif
 498         }
 499         return -1;
 500 }
 501
 502 int netpoll_parse_options(struct netpoll *np, char *opt)
 503 {
 504         char *cur=opt, *delim;
 505         int ipv6;
 506         bool ipversion_set = false;
 507
 508         if (*cur != '@') {
 509                 if ((delim = strchr(cur, '@')) == NULL)
 510                         goto parse_failed;
 511                 *delim = 0;
 512                 if (kstrtou16(cur, 10, &np->local_port))
 513                         goto parse_failed;
 514                 cur = delim;
 515         }
 516         cur++;
 517
 518         if (*cur != '/') {
 519                 ipversion_set = true;
 520                 if ((delim = strchr(cur, '/')) == NULL)
 521                         goto parse_failed;
 522                 *delim = 0;
 523                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 524                 if (ipv6 < 0)
 525                         goto parse_failed;
 526                 else
 527                         np->ipv6 = (bool)ipv6;
 528                 cur = delim;
 529         }
 530         cur++;
 531
 532         if (*cur != ',') {
 533                 /* parse out dev name */
 534                 if ((delim = strchr(cur, ',')) == NULL)
 535                         goto parse_failed;
 536                 *delim = 0;
 537                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 538                 cur = delim;
 539         }
 540         cur++;
 541
 542         if (*cur != '@') {
 543                 /* dst port */
 544                 if ((delim = strchr(cur, '@')) == NULL)
 545                         goto parse_failed;
 546                 *delim = 0;
 547                 if (*cur == ' ' || *cur == '\t')
 548                         np_info(np, "warning: whitespace is not allowed\n");
 549                 if (kstrtou16(cur, 10, &np->remote_port))
 550                         goto parse_failed;
 551                 cur = delim;
 552         }
 553         cur++;
 554
 555         /* dst ip */
 556         if ((delim = strchr(cur, '/')) == NULL)
 557                 goto parse_failed;
 558         *delim = 0;
 559         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 560         if (ipv6 < 0)
 561                 goto parse_failed;
 562         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 563                 goto parse_failed;
 564         else
 565                 np->ipv6 = (bool)ipv6;
 566         cur = delim + 1;
 567
 568         if (*cur != 0) {
 569                 /* MAC address */
 570                 if (!mac_pton(cur, np->remote_mac))
 571                         goto parse_failed;
 572         }
 573
 574         netpoll_print_options(np);
 575
 576         return 0;
 577
 578  parse_failed:
 579         np_info(np, "couldn't parse config at '%s'!\n", cur);
 580         return -1;
 581 }
 582 EXPORT_SYMBOL(netpoll_parse_options);
 583
 584 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 585 {
 586         struct netpoll_info *npinfo;
 587         const struct net_device_ops *ops;
 588         int err;
 589
 590         np->dev = ndev;
 591         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 592
 593         if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {
 594                 np_err(np, "%s doesn't support polling, aborting\n",
 595                        np->dev_name);
 596                 err = -ENOTSUPP;
 597                 goto out;
 598         }
 599
 600         if (!ndev->npinfo) {
 601                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 602                 if (!npinfo) {
 603                         err = -ENOMEM;
 604                         goto out;
 605                 }
 606
 607                 sema_init(&npinfo->dev_lock, 1);
 608                 skb_queue_head_init(&npinfo->txq);
 609                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 610
 611                 refcount_set(&npinfo->refcnt, 1);
 612
 613                 ops = np->dev->netdev_ops;
 614                 if (ops->ndo_netpoll_setup) {
 615                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 616                         if (err)
 617                                 goto free_npinfo;
 618                 }
 619         } else {
 620                 npinfo = rtnl_dereference(ndev->npinfo);
 621                 refcount_inc(&npinfo->refcnt);
 622         }
 623
 624         npinfo->netpoll = np;
 625
 626         /* last thing to do is link it to the net device structure */
 627         rcu_assign_pointer(ndev->npinfo, npinfo);
 628
 629         return 0;
 630
 631 free_npinfo:
 632         kfree(npinfo);
 633 out:
 634         return err;
 635 }
 636 EXPORT_SYMBOL_GPL(__netpoll_setup);
 637
 638 int netpoll_setup(struct netpoll *np)
 639 {
 640         struct net_device *ndev = NULL;
 641         struct in_device *in_dev;
 642         int err;
 643
 644         rtnl_lock();
 645         if (np->dev_name[0]) {
 646                 struct net *net = current->nsproxy->net_ns;
 647                 ndev = __dev_get_by_name(net, np->dev_name);
 648         }
 649         if (!ndev) {
 650                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 651                 err = -ENODEV;
 652                 goto unlock;
 653         }
 654         dev_hold(ndev);
 655
 656         if (netdev_master_upper_dev_get(ndev)) {
 657                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 658                 err = -EBUSY;
 659                 goto put;
 660         }
 661
 662         if (!netif_running(ndev)) {
 663                 unsigned long atmost, atleast;
 664
 665                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 666
 667                 err = dev_open(ndev, NULL);
 668
 669                 if (err) {
 670                         np_err(np, "failed to open %s\n", ndev->name);
 671                         goto put;
 672                 }
 673
 674                 rtnl_unlock();
 675                 atleast = jiffies + HZ/10;
 676                 atmost = jiffies + carrier_timeout * HZ;
 677                 while (!netif_carrier_ok(ndev)) {
 678                         if (time_after(jiffies, atmost)) {
 679                                 np_notice(np, "timeout waiting for carrier\n");
 680                                 break;
 681                         }
 682                         msleep(1);
 683                 }
 684
 685                 /* If carrier appears to come up instantly, we don't
 686                  * trust it and pause so that we don't pump all our
 687                  * queued console messages into the bitbucket.
 688                  */
 689
 690                 if (time_before(jiffies, atleast)) {
 691                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 692                         msleep(4000);
 693                 }
 694                 rtnl_lock();
 695         }
 696
 697         if (!np->local_ip.ip) {
 698                 if (!np->ipv6) {
 699                         const struct in_ifaddr *ifa;
 700
 701                         in_dev = __in_dev_get_rtnl(ndev);
 702                         if (!in_dev)
 703                                 goto put_noaddr;
 704
 705                         ifa = rtnl_dereference(in_dev->ifa_list);
 706                         if (!ifa) {
 707 put_noaddr:
 708                                 np_err(np, "no IP address for %s, aborting\n",
 709                                        np->dev_name);
 710                                 err = -EDESTADDRREQ;
 711                                 goto put;
 712                         }
 713
 714                         np->local_ip.ip = ifa->ifa_local;
 715                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 716                 } else {
 717 #if IS_ENABLED(CONFIG_IPV6)
 718                         struct inet6_dev *idev;
 719
 720                         err = -EDESTADDRREQ;
 721                         idev = __in6_dev_get(ndev);
 722                         if (idev) {
 723                                 struct inet6_ifaddr *ifp;
 724
 725                                 read_lock_bh(&idev->lock);
 726                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 727                                         if (!!(ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL) !=
 728                                             !!(ipv6_addr_type(&np->remote_ip.in6) & IPV6_ADDR_LINKLOCAL))
 729                                                 continue;
 730                                         np->local_ip.in6 = ifp->addr;
 731                                         err = 0;
 732                                         break;
 733                                 }
 734                                 read_unlock_bh(&idev->lock);
 735                         }
 736                         if (err) {
 737                                 np_err(np, "no IPv6 address for %s, aborting\n",
 738                                        np->dev_name);
 739                                 goto put;
 740                         } else
 741                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 742 #else
 743                         np_err(np, "IPv6 is not supported %s, aborting\n",
 744                                np->dev_name);
 745                         err = -EINVAL;
 746                         goto put;
 747 #endif
 748                 }
 749         }
 750
 751         /* fill up the skb queue */
 752         refill_skbs();
 753
 754         err = __netpoll_setup(np, ndev);
 755         if (err)
 756                 goto put;
 757
 758         rtnl_unlock();
 759         return 0;
 760
 761 put:
 762         dev_put(ndev);
 763 unlock:
 764         rtnl_unlock();
 765         return err;
 766 }
 767 EXPORT_SYMBOL(netpoll_setup);
 768
 769 static int __init netpoll_init(void)
 770 {
 771         skb_queue_head_init(&skb_pool);
 772         return 0;
 773 }
 774 core_initcall(netpoll_init);
 775
 776 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 777 {
 778         struct netpoll_info *npinfo =
 779                         container_of(rcu_head, struct netpoll_info, rcu);
 780
 781         skb_queue_purge(&npinfo->txq);
 782
 783         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 784         cancel_delayed_work(&npinfo->tx_work);
 785
 786         /* clean after last, unfinished work */
 787         __skb_queue_purge(&npinfo->txq);
 788         /* now cancel it again */
 789         cancel_delayed_work(&npinfo->tx_work);
 790         kfree(npinfo);
 791 }
 792
 793 void __netpoll_cleanup(struct netpoll *np)
 794 {
 795         struct netpoll_info *npinfo;
 796
 797         npinfo = rtnl_dereference(np->dev->npinfo);
 798         if (!npinfo)
 799                 return;
 800
 801         synchronize_srcu(&netpoll_srcu);
 802
 803         if (refcount_dec_and_test(&npinfo->refcnt)) {
 804                 const struct net_device_ops *ops;
 805
 806                 ops = np->dev->netdev_ops;
 807                 if (ops->ndo_netpoll_cleanup)
 808                         ops->ndo_netpoll_cleanup(np->dev);
 809
 810                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 811                 call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info);
 812         } else
 813                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 814 }
 815 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 816
 817 void __netpoll_free(struct netpoll *np)
 818 {
 819         ASSERT_RTNL();
 820
 821         /* Wait for transmitting packets to finish before freeing. */
 822         synchronize_rcu();
 823         __netpoll_cleanup(np);
 824         kfree(np);
 825 }
 826 EXPORT_SYMBOL_GPL(__netpoll_free);
 827
 828 void netpoll_cleanup(struct netpoll *np)
 829 {
 830         rtnl_lock();
 831         if (!np->dev)
 832                 goto out;
 833         __netpoll_cleanup(np);
 834         dev_put(np->dev);
 835         np->dev = NULL;
 836 out:
 837         rtnl_unlock();
 838 }
 839 EXPORT_SYMBOL(netpoll_cleanup);