net/core/netpoll.c

   1 /*
   2  * Common framework for low-level network console, dump, and debugger code
   3  *
   4  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
   5  *
   6  * based on the netconsole code from:
   7  *
   8  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
   9  * Copyright (C) 2002  Red Hat, Inc.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/moduleparam.h>
  15 #include <linux/kernel.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/string.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/inetdevice.h>
  21 #include <linux/inet.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/netpoll.h>
  24 #include <linux/sched.h>
  25 #include <linux/delay.h>
  26 #include <linux/rcupdate.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/slab.h>
  29 #include <linux/export.h>
  30 #include <linux/if_vlan.h>
  31 #include <net/tcp.h>
  32 #include <net/udp.h>
  33 #include <net/addrconf.h>
  34 #include <net/ndisc.h>
  35 #include <net/ip6_checksum.h>
  36 #include <asm/unaligned.h>
  37 #include <trace/events/napi.h>
  38
  39 /*
  40  * We maintain a small pool of fully-sized skbs, to make sure the
  41  * message gets out even in extreme OOM situations.
  42  */
  43
  44 #define MAX_UDP_CHUNK 1460
  45 #define MAX_SKBS 32
  46
  47 static struct sk_buff_head skb_pool;
  48
  49 DEFINE_STATIC_SRCU(netpoll_srcu);
  50
  51 #define USEC_PER_POLL   50
  52
  53 #define MAX_SKB_SIZE                                                    \
  54         (sizeof(struct ethhdr) +                                        \
  55          sizeof(struct iphdr) +                                         \
  56          sizeof(struct udphdr) +                                        \
  57          MAX_UDP_CHUNK)
  58
  59 static void zap_completion_queue(void);
  60 static void netpoll_async_cleanup(struct work_struct *work);
  61
  62 static unsigned int carrier_timeout = 4;
  63 module_param(carrier_timeout, uint, 0644);
  64
  65 #define np_info(np, fmt, ...)                           \
  66         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  67 #define np_err(np, fmt, ...)                            \
  68         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  69 #define np_notice(np, fmt, ...)                         \
  70         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  71
  72 static int netpoll_start_xmit(struct sk_buff *skb, struct net_device *dev,
  73                               struct netdev_queue *txq)
  74 {
  75         int status = NETDEV_TX_OK;
  76         netdev_features_t features;
  77
  78         features = netif_skb_features(skb);
  79
  80         if (skb_vlan_tag_present(skb) &&
  81             !vlan_hw_offload_capable(features, skb->vlan_proto)) {
  82                 skb = __vlan_hwaccel_push_inside(skb);
  83                 if (unlikely(!skb)) {
  84                         /* This is actually a packet drop, but we
  85                          * don't want the code that calls this
  86                          * function to try and operate on a NULL skb.
  87                          */
  88                         goto out;
  89                 }
  90         }
  91
  92         status = netdev_start_xmit(skb, dev, txq, false);
  93
  94 out:
  95         return status;
  96 }
  97
  98 static void queue_process(struct work_struct *work)
  99 {
 100         struct netpoll_info *npinfo =
 101                 container_of(work, struct netpoll_info, tx_work.work);
 102         struct sk_buff *skb;
 103         unsigned long flags;
 104
 105         while ((skb = skb_dequeue(&npinfo->txq))) {
 106                 struct net_device *dev = skb->dev;
 107                 struct netdev_queue *txq;
 108                 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                     netpoll_start_xmit(skb, dev, txq) != NETDEV_TX_OK) {
 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, "%pF 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         rcu_read_lock_bh();
 316         lockdep_assert_irqs_disabled();
 317
 318         npinfo = rcu_dereference_bh(np->dev->npinfo);
 319         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 320                 dev_kfree_skb_irq(skb);
 321                 return;
 322         }
 323
 324         /* don't get messages out of order, and no recursion */
 325         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 326                 struct netdev_queue *txq;
 327
 328                 txq = netdev_pick_tx(dev, skb, NULL);
 329
 330                 /* try until next clock tick */
 331                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 332                      tries > 0; --tries) {
 333                         if (HARD_TX_TRYLOCK(dev, txq)) {
 334                                 if (!netif_xmit_stopped(txq))
 335                                         status = netpoll_start_xmit(skb, dev, txq);
 336
 337                                 HARD_TX_UNLOCK(dev, txq);
 338
 339                                 if (status == NETDEV_TX_OK)
 340                                         break;
 341
 342                         }
 343
 344                         /* tickle device maybe there is some cleanup */
 345                         netpoll_poll_dev(np->dev);
 346
 347                         udelay(USEC_PER_POLL);
 348                 }
 349
 350                 WARN_ONCE(!irqs_disabled(),
 351                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 352                         dev->name, dev->netdev_ops->ndo_start_xmit);
 353
 354         }
 355
 356         if (status != NETDEV_TX_OK) {
 357                 skb_queue_tail(&npinfo->txq, skb);
 358                 schedule_delayed_work(&npinfo->tx_work,0);
 359         }
 360         rcu_read_unlock_bh();
 361 }
 362 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 363
 364 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 365 {
 366         int total_len, ip_len, udp_len;
 367         struct sk_buff *skb;
 368         struct udphdr *udph;
 369         struct iphdr *iph;
 370         struct ethhdr *eth;
 371         static atomic_t ip_ident;
 372         struct ipv6hdr *ip6h;
 373
 374         WARN_ON_ONCE(!irqs_disabled());
 375
 376         udp_len = len + sizeof(*udph);
 377         if (np->ipv6)
 378                 ip_len = udp_len + sizeof(*ip6h);
 379         else
 380                 ip_len = udp_len + sizeof(*iph);
 381
 382         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 383
 384         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 385                        total_len - len);
 386         if (!skb)
 387                 return;
 388
 389         skb_copy_to_linear_data(skb, msg, len);
 390         skb_put(skb, len);
 391
 392         skb_push(skb, sizeof(*udph));
 393         skb_reset_transport_header(skb);
 394         udph = udp_hdr(skb);
 395         udph->source = htons(np->local_port);
 396         udph->dest = htons(np->remote_port);
 397         udph->len = htons(udp_len);
 398
 399         if (np->ipv6) {
 400                 udph->check = 0;
 401                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 402                                               &np->remote_ip.in6,
 403                                               udp_len, IPPROTO_UDP,
 404                                               csum_partial(udph, udp_len, 0));
 405                 if (udph->check == 0)
 406                         udph->check = CSUM_MANGLED_0;
 407
 408                 skb_push(skb, sizeof(*ip6h));
 409                 skb_reset_network_header(skb);
 410                 ip6h = ipv6_hdr(skb);
 411
 412                 /* ip6h->version = 6; ip6h->priority = 0; */
 413                 put_unaligned(0x60, (unsigned char *)ip6h);
 414                 ip6h->flow_lbl[0] = 0;
 415                 ip6h->flow_lbl[1] = 0;
 416                 ip6h->flow_lbl[2] = 0;
 417
 418                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 419                 ip6h->nexthdr = IPPROTO_UDP;
 420                 ip6h->hop_limit = 32;
 421                 ip6h->saddr = np->local_ip.in6;
 422                 ip6h->daddr = np->remote_ip.in6;
 423
 424                 eth = skb_push(skb, ETH_HLEN);
 425                 skb_reset_mac_header(skb);
 426                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 427         } else {
 428                 udph->check = 0;
 429                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 430                                                 np->remote_ip.ip,
 431                                                 udp_len, IPPROTO_UDP,
 432                                                 csum_partial(udph, udp_len, 0));
 433                 if (udph->check == 0)
 434                         udph->check = CSUM_MANGLED_0;
 435
 436                 skb_push(skb, sizeof(*iph));
 437                 skb_reset_network_header(skb);
 438                 iph = ip_hdr(skb);
 439
 440                 /* iph->version = 4; iph->ihl = 5; */
 441                 put_unaligned(0x45, (unsigned char *)iph);
 442                 iph->tos      = 0;
 443                 put_unaligned(htons(ip_len), &(iph->tot_len));
 444                 iph->id       = htons(atomic_inc_return(&ip_ident));
 445                 iph->frag_off = 0;
 446                 iph->ttl      = 64;
 447                 iph->protocol = IPPROTO_UDP;
 448                 iph->check    = 0;
 449                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 450                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 451                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 452
 453                 eth = skb_push(skb, ETH_HLEN);
 454                 skb_reset_mac_header(skb);
 455                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 456         }
 457
 458         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 459         ether_addr_copy(eth->h_dest, np->remote_mac);
 460
 461         skb->dev = np->dev;
 462
 463         netpoll_send_skb(np, skb);
 464 }
 465 EXPORT_SYMBOL(netpoll_send_udp);
 466
 467 void netpoll_print_options(struct netpoll *np)
 468 {
 469         np_info(np, "local port %d\n", np->local_port);
 470         if (np->ipv6)
 471                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 472         else
 473                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 474         np_info(np, "interface '%s'\n", np->dev_name);
 475         np_info(np, "remote port %d\n", np->remote_port);
 476         if (np->ipv6)
 477                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 478         else
 479                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 480         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 481 }
 482 EXPORT_SYMBOL(netpoll_print_options);
 483
 484 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 485 {
 486         const char *end;
 487
 488         if (!strchr(str, ':') &&
 489             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 490                 if (!*end)
 491                         return 0;
 492         }
 493         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 494 #if IS_ENABLED(CONFIG_IPV6)
 495                 if (!*end)
 496                         return 1;
 497 #else
 498                 return -1;
 499 #endif
 500         }
 501         return -1;
 502 }
 503
 504 int netpoll_parse_options(struct netpoll *np, char *opt)
 505 {
 506         char *cur=opt, *delim;
 507         int ipv6;
 508         bool ipversion_set = false;
 509
 510         if (*cur != '@') {
 511                 if ((delim = strchr(cur, '@')) == NULL)
 512                         goto parse_failed;
 513                 *delim = 0;
 514                 if (kstrtou16(cur, 10, &np->local_port))
 515                         goto parse_failed;
 516                 cur = delim;
 517         }
 518         cur++;
 519
 520         if (*cur != '/') {
 521                 ipversion_set = true;
 522                 if ((delim = strchr(cur, '/')) == NULL)
 523                         goto parse_failed;
 524                 *delim = 0;
 525                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 526                 if (ipv6 < 0)
 527                         goto parse_failed;
 528                 else
 529                         np->ipv6 = (bool)ipv6;
 530                 cur = delim;
 531         }
 532         cur++;
 533
 534         if (*cur != ',') {
 535                 /* parse out dev name */
 536                 if ((delim = strchr(cur, ',')) == NULL)
 537                         goto parse_failed;
 538                 *delim = 0;
 539                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 540                 cur = delim;
 541         }
 542         cur++;
 543
 544         if (*cur != '@') {
 545                 /* dst port */
 546                 if ((delim = strchr(cur, '@')) == NULL)
 547                         goto parse_failed;
 548                 *delim = 0;
 549                 if (*cur == ' ' || *cur == '\t')
 550                         np_info(np, "warning: whitespace is not allowed\n");
 551                 if (kstrtou16(cur, 10, &np->remote_port))
 552                         goto parse_failed;
 553                 cur = delim;
 554         }
 555         cur++;
 556
 557         /* dst ip */
 558         if ((delim = strchr(cur, '/')) == NULL)
 559                 goto parse_failed;
 560         *delim = 0;
 561         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 562         if (ipv6 < 0)
 563                 goto parse_failed;
 564         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 565                 goto parse_failed;
 566         else
 567                 np->ipv6 = (bool)ipv6;
 568         cur = delim + 1;
 569
 570         if (*cur != 0) {
 571                 /* MAC address */
 572                 if (!mac_pton(cur, np->remote_mac))
 573                         goto parse_failed;
 574         }
 575
 576         netpoll_print_options(np);
 577
 578         return 0;
 579
 580  parse_failed:
 581         np_info(np, "couldn't parse config at '%s'!\n", cur);
 582         return -1;
 583 }
 584 EXPORT_SYMBOL(netpoll_parse_options);
 585
 586 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 587 {
 588         struct netpoll_info *npinfo;
 589         const struct net_device_ops *ops;
 590         int err;
 591
 592         np->dev = ndev;
 593         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 594         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
 595
 596         if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {
 597                 np_err(np, "%s doesn't support polling, aborting\n",
 598                        np->dev_name);
 599                 err = -ENOTSUPP;
 600                 goto out;
 601         }
 602
 603         if (!ndev->npinfo) {
 604                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 605                 if (!npinfo) {
 606                         err = -ENOMEM;
 607                         goto out;
 608                 }
 609
 610                 sema_init(&npinfo->dev_lock, 1);
 611                 skb_queue_head_init(&npinfo->txq);
 612                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 613
 614                 refcount_set(&npinfo->refcnt, 1);
 615
 616                 ops = np->dev->netdev_ops;
 617                 if (ops->ndo_netpoll_setup) {
 618                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 619                         if (err)
 620                                 goto free_npinfo;
 621                 }
 622         } else {
 623                 npinfo = rtnl_dereference(ndev->npinfo);
 624                 refcount_inc(&npinfo->refcnt);
 625         }
 626
 627         npinfo->netpoll = np;
 628
 629         /* last thing to do is link it to the net device structure */
 630         rcu_assign_pointer(ndev->npinfo, npinfo);
 631
 632         return 0;
 633
 634 free_npinfo:
 635         kfree(npinfo);
 636 out:
 637         return err;
 638 }
 639 EXPORT_SYMBOL_GPL(__netpoll_setup);
 640
 641 int netpoll_setup(struct netpoll *np)
 642 {
 643         struct net_device *ndev = NULL;
 644         struct in_device *in_dev;
 645         int err;
 646
 647         rtnl_lock();
 648         if (np->dev_name[0]) {
 649                 struct net *net = current->nsproxy->net_ns;
 650                 ndev = __dev_get_by_name(net, np->dev_name);
 651         }
 652         if (!ndev) {
 653                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 654                 err = -ENODEV;
 655                 goto unlock;
 656         }
 657         dev_hold(ndev);
 658
 659         if (netdev_master_upper_dev_get(ndev)) {
 660                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 661                 err = -EBUSY;
 662                 goto put;
 663         }
 664
 665         if (!netif_running(ndev)) {
 666                 unsigned long atmost, atleast;
 667
 668                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 669
 670                 err = dev_open(ndev);
 671
 672                 if (err) {
 673                         np_err(np, "failed to open %s\n", ndev->name);
 674                         goto put;
 675                 }
 676
 677                 rtnl_unlock();
 678                 atleast = jiffies + HZ/10;
 679                 atmost = jiffies + carrier_timeout * HZ;
 680                 while (!netif_carrier_ok(ndev)) {
 681                         if (time_after(jiffies, atmost)) {
 682                                 np_notice(np, "timeout waiting for carrier\n");
 683                                 break;
 684                         }
 685                         msleep(1);
 686                 }
 687
 688                 /* If carrier appears to come up instantly, we don't
 689                  * trust it and pause so that we don't pump all our
 690                  * queued console messages into the bitbucket.
 691                  */
 692
 693                 if (time_before(jiffies, atleast)) {
 694                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 695                         msleep(4000);
 696                 }
 697                 rtnl_lock();
 698         }
 699
 700         if (!np->local_ip.ip) {
 701                 if (!np->ipv6) {
 702                         in_dev = __in_dev_get_rtnl(ndev);
 703
 704                         if (!in_dev || !in_dev->ifa_list) {
 705                                 np_err(np, "no IP address for %s, aborting\n",
 706                                        np->dev_name);
 707                                 err = -EDESTADDRREQ;
 708                                 goto put;
 709                         }
 710
 711                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
 712                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 713                 } else {
 714 #if IS_ENABLED(CONFIG_IPV6)
 715                         struct inet6_dev *idev;
 716
 717                         err = -EDESTADDRREQ;
 718                         idev = __in6_dev_get(ndev);
 719                         if (idev) {
 720                                 struct inet6_ifaddr *ifp;
 721
 722                                 read_lock_bh(&idev->lock);
 723                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 724                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
 725                                                 continue;
 726                                         np->local_ip.in6 = ifp->addr;
 727                                         err = 0;
 728                                         break;
 729                                 }
 730                                 read_unlock_bh(&idev->lock);
 731                         }
 732                         if (err) {
 733                                 np_err(np, "no IPv6 address for %s, aborting\n",
 734                                        np->dev_name);
 735                                 goto put;
 736                         } else
 737                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 738 #else
 739                         np_err(np, "IPv6 is not supported %s, aborting\n",
 740                                np->dev_name);
 741                         err = -EINVAL;
 742                         goto put;
 743 #endif
 744                 }
 745         }
 746
 747         /* fill up the skb queue */
 748         refill_skbs();
 749
 750         err = __netpoll_setup(np, ndev);
 751         if (err)
 752                 goto put;
 753
 754         rtnl_unlock();
 755         return 0;
 756
 757 put:
 758         dev_put(ndev);
 759 unlock:
 760         rtnl_unlock();
 761         return err;
 762 }
 763 EXPORT_SYMBOL(netpoll_setup);
 764
 765 static int __init netpoll_init(void)
 766 {
 767         skb_queue_head_init(&skb_pool);
 768         return 0;
 769 }
 770 core_initcall(netpoll_init);
 771
 772 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 773 {
 774         struct netpoll_info *npinfo =
 775                         container_of(rcu_head, struct netpoll_info, rcu);
 776
 777         skb_queue_purge(&npinfo->txq);
 778
 779         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 780         cancel_delayed_work(&npinfo->tx_work);
 781
 782         /* clean after last, unfinished work */
 783         __skb_queue_purge(&npinfo->txq);
 784         /* now cancel it again */
 785         cancel_delayed_work(&npinfo->tx_work);
 786         kfree(npinfo);
 787 }
 788
 789 void __netpoll_cleanup(struct netpoll *np)
 790 {
 791         struct netpoll_info *npinfo;
 792
 793         /* rtnl_dereference would be preferable here but
 794          * rcu_cleanup_netpoll path can put us in here safely without
 795          * holding the rtnl, so plain rcu_dereference it is
 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_bh(&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 static void netpoll_async_cleanup(struct work_struct *work)
 818 {
 819         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
 820
 821         rtnl_lock();
 822         __netpoll_cleanup(np);
 823         rtnl_unlock();
 824         kfree(np);
 825 }
 826
 827 void __netpoll_free_async(struct netpoll *np)
 828 {
 829         schedule_work(&np->cleanup_work);
 830 }
 831 EXPORT_SYMBOL_GPL(__netpoll_free_async);
 832
 833 void netpoll_cleanup(struct netpoll *np)
 834 {
 835         rtnl_lock();
 836         if (!np->dev)
 837                 goto out;
 838         __netpoll_cleanup(np);
 839         dev_put(np->dev);
 840         np->dev = NULL;
 841 out:
 842         rtnl_unlock();
 843 }
 844 EXPORT_SYMBOL(netpoll_cleanup);