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