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 int netif_local_xmit_active(struct net_device *dev)
 141 {
 142         int i;
 143
 144         for (i = 0; i < dev->num_tx_queues; i++) {
 145                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 146
 147                 if (READ_ONCE(txq->xmit_lock_owner) == smp_processor_id())
 148                         return 1;
 149         }
 150
 151         return 0;
 152 }
 153
 154 static void poll_one_napi(struct napi_struct *napi)
 155 {
 156         int work;
 157
 158         /* If we set this bit but see that it has already been set,
 159          * that indicates that napi has been disabled and we need
 160          * to abort this operation
 161          */
 162         if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
 163                 return;
 164
 165         /* We explicilty pass the polling call a budget of 0 to
 166          * indicate that we are clearing the Tx path only.
 167          */
 168         work = napi->poll(napi, 0);
 169         WARN_ONCE(work, "%pS exceeded budget in poll\n", napi->poll);
 170         trace_napi_poll(napi, work, 0);
 171
 172         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 173 }
 174
 175 static void poll_napi(struct net_device *dev)
 176 {
 177         struct napi_struct *napi;
 178         int cpu = smp_processor_id();
 179
 180         list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
 181                 if (cmpxchg(&napi->poll_owner, -1, cpu) == -1) {
 182                         poll_one_napi(napi);
 183                         smp_store_release(&napi->poll_owner, -1);
 184                 }
 185         }
 186 }
 187
 188 void netpoll_poll_dev(struct net_device *dev)
 189 {
 190         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 191         const struct net_device_ops *ops;
 192
 193         /* Don't do any rx activity if the dev_lock mutex is held
 194          * the dev_open/close paths use this to block netpoll activity
 195          * while changing device state
 196          */
 197         if (!ni || down_trylock(&ni->dev_lock))
 198                 return;
 199
 200         /* Some drivers will take the same locks in poll and xmit,
 201          * we can't poll if local CPU is already in xmit.
 202          */
 203         if (!netif_running(dev) || netif_local_xmit_active(dev)) {
 204                 up(&ni->dev_lock);
 205                 return;
 206         }
 207
 208         ops = dev->netdev_ops;
 209         if (ops->ndo_poll_controller)
 210                 ops->ndo_poll_controller(dev);
 211
 212         poll_napi(dev);
 213
 214         up(&ni->dev_lock);
 215
 216         zap_completion_queue();
 217 }
 218 EXPORT_SYMBOL(netpoll_poll_dev);
 219
 220 void netpoll_poll_disable(struct net_device *dev)
 221 {
 222         struct netpoll_info *ni;
 223         int idx;
 224         might_sleep();
 225         idx = srcu_read_lock(&netpoll_srcu);
 226         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 227         if (ni)
 228                 down(&ni->dev_lock);
 229         srcu_read_unlock(&netpoll_srcu, idx);
 230 }
 231
 232 void netpoll_poll_enable(struct net_device *dev)
 233 {
 234         struct netpoll_info *ni;
 235         rcu_read_lock();
 236         ni = rcu_dereference(dev->npinfo);
 237         if (ni)
 238                 up(&ni->dev_lock);
 239         rcu_read_unlock();
 240 }
 241
 242 static void refill_skbs(void)
 243 {
 244         struct sk_buff *skb;
 245         unsigned long flags;
 246
 247         spin_lock_irqsave(&skb_pool.lock, flags);
 248         while (skb_pool.qlen < MAX_SKBS) {
 249                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 250                 if (!skb)
 251                         break;
 252
 253                 __skb_queue_tail(&skb_pool, skb);
 254         }
 255         spin_unlock_irqrestore(&skb_pool.lock, flags);
 256 }
 257
 258 static void zap_completion_queue(void)
 259 {
 260         unsigned long flags;
 261         struct softnet_data *sd = &get_cpu_var(softnet_data);
 262
 263         if (sd->completion_queue) {
 264                 struct sk_buff *clist;
 265
 266                 local_irq_save(flags);
 267                 clist = sd->completion_queue;
 268                 sd->completion_queue = NULL;
 269                 local_irq_restore(flags);
 270
 271                 while (clist != NULL) {
 272                         struct sk_buff *skb = clist;
 273                         clist = clist->next;
 274                         if (!skb_irq_freeable(skb)) {
 275                                 refcount_set(&skb->users, 1);
 276                                 dev_kfree_skb_any(skb); /* put this one back */
 277                         } else {
 278                                 __kfree_skb(skb);
 279                         }
 280                 }
 281         }
 282
 283         put_cpu_var(softnet_data);
 284 }
 285
 286 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 287 {
 288         int count = 0;
 289         struct sk_buff *skb;
 290
 291         zap_completion_queue();
 292         refill_skbs();
 293 repeat:
 294
 295         skb = alloc_skb(len, GFP_ATOMIC);
 296         if (!skb)
 297                 skb = skb_dequeue(&skb_pool);
 298
 299         if (!skb) {
 300                 if (++count < 10) {
 301                         netpoll_poll_dev(np->dev);
 302                         goto repeat;
 303                 }
 304                 return NULL;
 305         }
 306
 307         refcount_set(&skb->users, 1);
 308         skb_reserve(skb, reserve);
 309         return skb;
 310 }
 311
 312 static int netpoll_owner_active(struct net_device *dev)
 313 {
 314         struct napi_struct *napi;
 315
 316         list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
 317                 if (READ_ONCE(napi->poll_owner) == smp_processor_id())
 318                         return 1;
 319         }
 320         return 0;
 321 }
 322
 323 /* call with IRQ disabled */
 324 static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 325 {
 326         netdev_tx_t status = NETDEV_TX_BUSY;
 327         struct net_device *dev;
 328         unsigned long tries;
 329         /* It is up to the caller to keep npinfo alive. */
 330         struct netpoll_info *npinfo;
 331
 332         lockdep_assert_irqs_disabled();
 333
 334         dev = np->dev;
 335         npinfo = rcu_dereference_bh(dev->npinfo);
 336
 337         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 338                 dev_kfree_skb_irq(skb);
 339                 return NET_XMIT_DROP;
 340         }
 341
 342         /* don't get messages out of order, and no recursion */
 343         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 344                 struct netdev_queue *txq;
 345
 346                 txq = netdev_core_pick_tx(dev, skb, NULL);
 347
 348                 /* try until next clock tick */
 349                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 350                      tries > 0; --tries) {
 351                         if (HARD_TX_TRYLOCK(dev, txq)) {
 352                                 if (!netif_xmit_stopped(txq))
 353                                         status = netpoll_start_xmit(skb, dev, txq);
 354
 355                                 HARD_TX_UNLOCK(dev, txq);
 356
 357                                 if (dev_xmit_complete(status))
 358                                         break;
 359
 360                         }
 361
 362                         /* tickle device maybe there is some cleanup */
 363                         netpoll_poll_dev(np->dev);
 364
 365                         udelay(USEC_PER_POLL);
 366                 }
 367
 368                 WARN_ONCE(!irqs_disabled(),
 369                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pS)\n",
 370                         dev->name, dev->netdev_ops->ndo_start_xmit);
 371
 372         }
 373
 374         if (!dev_xmit_complete(status)) {
 375                 skb_queue_tail(&npinfo->txq, skb);
 376                 schedule_delayed_work(&npinfo->tx_work,0);
 377         }
 378         return NETDEV_TX_OK;
 379 }
 380
 381 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 382 {
 383         unsigned long flags;
 384         netdev_tx_t ret;
 385
 386         if (unlikely(!np)) {
 387                 dev_kfree_skb_irq(skb);
 388                 ret = NET_XMIT_DROP;
 389         } else {
 390                 local_irq_save(flags);
 391                 ret = __netpoll_send_skb(np, skb);
 392                 local_irq_restore(flags);
 393         }
 394         return ret;
 395 }
 396 EXPORT_SYMBOL(netpoll_send_skb);
 397
 398 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 399 {
 400         int total_len, ip_len, udp_len;
 401         struct sk_buff *skb;
 402         struct udphdr *udph;
 403         struct iphdr *iph;
 404         struct ethhdr *eth;
 405         static atomic_t ip_ident;
 406         struct ipv6hdr *ip6h;
 407
 408         if (!IS_ENABLED(CONFIG_PREEMPT_RT))
 409                 WARN_ON_ONCE(!irqs_disabled());
 410
 411         udp_len = len + sizeof(*udph);
 412         if (np->ipv6)
 413                 ip_len = udp_len + sizeof(*ip6h);
 414         else
 415                 ip_len = udp_len + sizeof(*iph);
 416
 417         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 418
 419         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 420                        total_len - len);
 421         if (!skb)
 422                 return;
 423
 424         skb_copy_to_linear_data(skb, msg, len);
 425         skb_put(skb, len);
 426
 427         skb_push(skb, sizeof(*udph));
 428         skb_reset_transport_header(skb);
 429         udph = udp_hdr(skb);
 430         udph->source = htons(np->local_port);
 431         udph->dest = htons(np->remote_port);
 432         udph->len = htons(udp_len);
 433
 434         if (np->ipv6) {
 435                 udph->check = 0;
 436                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 437                                               &np->remote_ip.in6,
 438                                               udp_len, IPPROTO_UDP,
 439                                               csum_partial(udph, udp_len, 0));
 440                 if (udph->check == 0)
 441                         udph->check = CSUM_MANGLED_0;
 442
 443                 skb_push(skb, sizeof(*ip6h));
 444                 skb_reset_network_header(skb);
 445                 ip6h = ipv6_hdr(skb);
 446
 447                 /* ip6h->version = 6; ip6h->priority = 0; */
 448                 *(unsigned char *)ip6h = 0x60;
 449                 ip6h->flow_lbl[0] = 0;
 450                 ip6h->flow_lbl[1] = 0;
 451                 ip6h->flow_lbl[2] = 0;
 452
 453                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 454                 ip6h->nexthdr = IPPROTO_UDP;
 455                 ip6h->hop_limit = 32;
 456                 ip6h->saddr = np->local_ip.in6;
 457                 ip6h->daddr = np->remote_ip.in6;
 458
 459                 eth = skb_push(skb, ETH_HLEN);
 460                 skb_reset_mac_header(skb);
 461                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 462         } else {
 463                 udph->check = 0;
 464                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 465                                                 np->remote_ip.ip,
 466                                                 udp_len, IPPROTO_UDP,
 467                                                 csum_partial(udph, udp_len, 0));
 468                 if (udph->check == 0)
 469                         udph->check = CSUM_MANGLED_0;
 470
 471                 skb_push(skb, sizeof(*iph));
 472                 skb_reset_network_header(skb);
 473                 iph = ip_hdr(skb);
 474
 475                 /* iph->version = 4; iph->ihl = 5; */
 476                 *(unsigned char *)iph = 0x45;
 477                 iph->tos      = 0;
 478                 put_unaligned(htons(ip_len), &(iph->tot_len));
 479                 iph->id       = htons(atomic_inc_return(&ip_ident));
 480                 iph->frag_off = 0;
 481                 iph->ttl      = 64;
 482                 iph->protocol = IPPROTO_UDP;
 483                 iph->check    = 0;
 484                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 485                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 486                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 487
 488                 eth = skb_push(skb, ETH_HLEN);
 489                 skb_reset_mac_header(skb);
 490                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 491         }
 492
 493         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 494         ether_addr_copy(eth->h_dest, np->remote_mac);
 495
 496         skb->dev = np->dev;
 497
 498         netpoll_send_skb(np, skb);
 499 }
 500 EXPORT_SYMBOL(netpoll_send_udp);
 501
 502 void netpoll_print_options(struct netpoll *np)
 503 {
 504         np_info(np, "local port %d\n", np->local_port);
 505         if (np->ipv6)
 506                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 507         else
 508                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 509         np_info(np, "interface '%s'\n", np->dev_name);
 510         np_info(np, "remote port %d\n", np->remote_port);
 511         if (np->ipv6)
 512                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 513         else
 514                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 515         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 516 }
 517 EXPORT_SYMBOL(netpoll_print_options);
 518
 519 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 520 {
 521         const char *end;
 522
 523         if (!strchr(str, ':') &&
 524             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 525                 if (!*end)
 526                         return 0;
 527         }
 528         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 529 #if IS_ENABLED(CONFIG_IPV6)
 530                 if (!*end)
 531                         return 1;
 532 #else
 533                 return -1;
 534 #endif
 535         }
 536         return -1;
 537 }
 538
 539 int netpoll_parse_options(struct netpoll *np, char *opt)
 540 {
 541         char *cur=opt, *delim;
 542         int ipv6;
 543         bool ipversion_set = false;
 544
 545         if (*cur != '@') {
 546                 if ((delim = strchr(cur, '@')) == NULL)
 547                         goto parse_failed;
 548                 *delim = 0;
 549                 if (kstrtou16(cur, 10, &np->local_port))
 550                         goto parse_failed;
 551                 cur = delim;
 552         }
 553         cur++;
 554
 555         if (*cur != '/') {
 556                 ipversion_set = true;
 557                 if ((delim = strchr(cur, '/')) == NULL)
 558                         goto parse_failed;
 559                 *delim = 0;
 560                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 561                 if (ipv6 < 0)
 562                         goto parse_failed;
 563                 else
 564                         np->ipv6 = (bool)ipv6;
 565                 cur = delim;
 566         }
 567         cur++;
 568
 569         if (*cur != ',') {
 570                 /* parse out dev name */
 571                 if ((delim = strchr(cur, ',')) == NULL)
 572                         goto parse_failed;
 573                 *delim = 0;
 574                 strscpy(np->dev_name, cur, sizeof(np->dev_name));
 575                 cur = delim;
 576         }
 577         cur++;
 578
 579         if (*cur != '@') {
 580                 /* dst port */
 581                 if ((delim = strchr(cur, '@')) == NULL)
 582                         goto parse_failed;
 583                 *delim = 0;
 584                 if (*cur == ' ' || *cur == '\t')
 585                         np_info(np, "warning: whitespace is not allowed\n");
 586                 if (kstrtou16(cur, 10, &np->remote_port))
 587                         goto parse_failed;
 588                 cur = delim;
 589         }
 590         cur++;
 591
 592         /* dst ip */
 593         if ((delim = strchr(cur, '/')) == NULL)
 594                 goto parse_failed;
 595         *delim = 0;
 596         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 597         if (ipv6 < 0)
 598                 goto parse_failed;
 599         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 600                 goto parse_failed;
 601         else
 602                 np->ipv6 = (bool)ipv6;
 603         cur = delim + 1;
 604
 605         if (*cur != 0) {
 606                 /* MAC address */
 607                 if (!mac_pton(cur, np->remote_mac))
 608                         goto parse_failed;
 609         }
 610
 611         netpoll_print_options(np);
 612
 613         return 0;
 614
 615  parse_failed:
 616         np_info(np, "couldn't parse config at '%s'!\n", cur);
 617         return -1;
 618 }
 619 EXPORT_SYMBOL(netpoll_parse_options);
 620
 621 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 622 {
 623         struct netpoll_info *npinfo;
 624         const struct net_device_ops *ops;
 625         int err;
 626
 627         np->dev = ndev;
 628         strscpy(np->dev_name, ndev->name, IFNAMSIZ);
 629
 630         if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {
 631                 np_err(np, "%s doesn't support polling, aborting\n",
 632                        np->dev_name);
 633                 err = -ENOTSUPP;
 634                 goto out;
 635         }
 636
 637         if (!ndev->npinfo) {
 638                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 639                 if (!npinfo) {
 640                         err = -ENOMEM;
 641                         goto out;
 642                 }
 643
 644                 sema_init(&npinfo->dev_lock, 1);
 645                 skb_queue_head_init(&npinfo->txq);
 646                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 647
 648                 refcount_set(&npinfo->refcnt, 1);
 649
 650                 ops = np->dev->netdev_ops;
 651                 if (ops->ndo_netpoll_setup) {
 652                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 653                         if (err)
 654                                 goto free_npinfo;
 655                 }
 656         } else {
 657                 npinfo = rtnl_dereference(ndev->npinfo);
 658                 refcount_inc(&npinfo->refcnt);
 659         }
 660
 661         npinfo->netpoll = np;
 662
 663         /* last thing to do is link it to the net device structure */
 664         rcu_assign_pointer(ndev->npinfo, npinfo);
 665
 666         return 0;
 667
 668 free_npinfo:
 669         kfree(npinfo);
 670 out:
 671         return err;
 672 }
 673 EXPORT_SYMBOL_GPL(__netpoll_setup);
 674
 675 int netpoll_setup(struct netpoll *np)
 676 {
 677         struct net_device *ndev = NULL;
 678         struct in_device *in_dev;
 679         int err;
 680
 681         rtnl_lock();
 682         if (np->dev_name[0]) {
 683                 struct net *net = current->nsproxy->net_ns;
 684                 ndev = __dev_get_by_name(net, np->dev_name);
 685         }
 686         if (!ndev) {
 687                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 688                 err = -ENODEV;
 689                 goto unlock;
 690         }
 691         netdev_hold(ndev, &np->dev_tracker, GFP_KERNEL);
 692
 693         if (netdev_master_upper_dev_get(ndev)) {
 694                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 695                 err = -EBUSY;
 696                 goto put;
 697         }
 698
 699         if (!netif_running(ndev)) {
 700                 unsigned long atmost;
 701
 702                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 703
 704                 err = dev_open(ndev, NULL);
 705
 706                 if (err) {
 707                         np_err(np, "failed to open %s\n", ndev->name);
 708                         goto put;
 709                 }
 710
 711                 rtnl_unlock();
 712                 atmost = jiffies + carrier_timeout * HZ;
 713                 while (!netif_carrier_ok(ndev)) {
 714                         if (time_after(jiffies, atmost)) {
 715                                 np_notice(np, "timeout waiting for carrier\n");
 716                                 break;
 717                         }
 718                         msleep(1);
 719                 }
 720
 721                 rtnl_lock();
 722         }
 723
 724         if (!np->local_ip.ip) {
 725                 if (!np->ipv6) {
 726                         const struct in_ifaddr *ifa;
 727
 728                         in_dev = __in_dev_get_rtnl(ndev);
 729                         if (!in_dev)
 730                                 goto put_noaddr;
 731
 732                         ifa = rtnl_dereference(in_dev->ifa_list);
 733                         if (!ifa) {
 734 put_noaddr:
 735                                 np_err(np, "no IP address for %s, aborting\n",
 736                                        np->dev_name);
 737                                 err = -EDESTADDRREQ;
 738                                 goto put;
 739                         }
 740
 741                         np->local_ip.ip = ifa->ifa_local;
 742                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 743                 } else {
 744 #if IS_ENABLED(CONFIG_IPV6)
 745                         struct inet6_dev *idev;
 746
 747                         err = -EDESTADDRREQ;
 748                         idev = __in6_dev_get(ndev);
 749                         if (idev) {
 750                                 struct inet6_ifaddr *ifp;
 751
 752                                 read_lock_bh(&idev->lock);
 753                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 754                                         if (!!(ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL) !=
 755                                             !!(ipv6_addr_type(&np->remote_ip.in6) & IPV6_ADDR_LINKLOCAL))
 756                                                 continue;
 757                                         np->local_ip.in6 = ifp->addr;
 758                                         err = 0;
 759                                         break;
 760                                 }
 761                                 read_unlock_bh(&idev->lock);
 762                         }
 763                         if (err) {
 764                                 np_err(np, "no IPv6 address for %s, aborting\n",
 765                                        np->dev_name);
 766                                 goto put;
 767                         } else
 768                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 769 #else
 770                         np_err(np, "IPv6 is not supported %s, aborting\n",
 771                                np->dev_name);
 772                         err = -EINVAL;
 773                         goto put;
 774 #endif
 775                 }
 776         }
 777
 778         /* fill up the skb queue */
 779         refill_skbs();
 780
 781         err = __netpoll_setup(np, ndev);
 782         if (err)
 783                 goto put;
 784         rtnl_unlock();
 785         return 0;
 786
 787 put:
 788         netdev_put(ndev, &np->dev_tracker);
 789 unlock:
 790         rtnl_unlock();
 791         return err;
 792 }
 793 EXPORT_SYMBOL(netpoll_setup);
 794
 795 static int __init netpoll_init(void)
 796 {
 797         skb_queue_head_init(&skb_pool);
 798         return 0;
 799 }
 800 core_initcall(netpoll_init);
 801
 802 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 803 {
 804         struct netpoll_info *npinfo =
 805                         container_of(rcu_head, struct netpoll_info, rcu);
 806
 807         skb_queue_purge(&npinfo->txq);
 808
 809         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 810         cancel_delayed_work(&npinfo->tx_work);
 811
 812         /* clean after last, unfinished work */
 813         __skb_queue_purge(&npinfo->txq);
 814         /* now cancel it again */
 815         cancel_delayed_work(&npinfo->tx_work);
 816         kfree(npinfo);
 817 }
 818
 819 void __netpoll_cleanup(struct netpoll *np)
 820 {
 821         struct netpoll_info *npinfo;
 822
 823         npinfo = rtnl_dereference(np->dev->npinfo);
 824         if (!npinfo)
 825                 return;
 826
 827         synchronize_srcu(&netpoll_srcu);
 828
 829         if (refcount_dec_and_test(&npinfo->refcnt)) {
 830                 const struct net_device_ops *ops;
 831
 832                 ops = np->dev->netdev_ops;
 833                 if (ops->ndo_netpoll_cleanup)
 834                         ops->ndo_netpoll_cleanup(np->dev);
 835
 836                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 837                 call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info);
 838         } else
 839                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 840 }
 841 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 842
 843 void __netpoll_free(struct netpoll *np)
 844 {
 845         ASSERT_RTNL();
 846
 847         /* Wait for transmitting packets to finish before freeing. */
 848         synchronize_rcu();
 849         __netpoll_cleanup(np);
 850         kfree(np);
 851 }
 852 EXPORT_SYMBOL_GPL(__netpoll_free);
 853
 854 void netpoll_cleanup(struct netpoll *np)
 855 {
 856         rtnl_lock();
 857         if (!np->dev)
 858                 goto out;
 859         __netpoll_cleanup(np);
 860         netdev_put(np->dev, &np->dev_tracker);
 861         np->dev = NULL;
 862 out:
 863         rtnl_unlock();
 864 }
 865 EXPORT_SYMBOL(netpoll_cleanup);