linux/net/core/netpoll.c
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   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
  47static struct sk_buff_head skb_pool;
  48
  49DEFINE_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
  59static void zap_completion_queue(void);
  60static void netpoll_async_cleanup(struct work_struct *work);
  61
  62static unsigned int carrier_timeout = 4;
  63module_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
  72static 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
  94out:
  95        return status;
  96}
  97
  98static 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/*
 139 * Check whether delayed processing was scheduled for our NIC. If so,
 140 * we attempt to grab the poll lock and use ->poll() to pump the card.
 141 * If this fails, either we've recursed in ->poll() or it's already
 142 * running on another CPU.
 143 *
 144 * Note: we don't mask interrupts with this lock because we're using
 145 * trylock here and interrupts are already disabled in the softirq
 146 * case. Further, we test the poll_owner to avoid recursion on UP
 147 * systems where the lock doesn't exist.
 148 */
 149static void poll_one_napi(struct napi_struct *napi)
 150{
 151        int work = 0;
 152
 153        /* net_rx_action's ->poll() invocations and our's are
 154         * synchronized by this test which is only made while
 155         * holding the napi->poll_lock.
 156         */
 157        if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 158                return;
 159
 160        /* If we set this bit but see that it has already been set,
 161         * that indicates that napi has been disabled and we need
 162         * to abort this operation
 163         */
 164        if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
 165                return;
 166
 167        /* We explicilty pass the polling call a budget of 0 to
 168         * indicate that we are clearing the Tx path only.
 169         */
 170        work = napi->poll(napi, 0);
 171        WARN_ONCE(work, "%pF exceeded budget in poll\n", napi->poll);
 172        trace_napi_poll(napi, work, 0);
 173
 174        clear_bit(NAPI_STATE_NPSVC, &napi->state);
 175}
 176
 177static void poll_napi(struct net_device *dev)
 178{
 179        struct napi_struct *napi;
 180        int cpu = smp_processor_id();
 181
 182        list_for_each_entry(napi, &dev->napi_list, dev_list) {
 183                if (cmpxchg(&napi->poll_owner, -1, cpu) == -1) {
 184                        poll_one_napi(napi);
 185                        smp_store_release(&napi->poll_owner, -1);
 186                }
 187        }
 188}
 189
 190static void netpoll_poll_dev(struct net_device *dev)
 191{
 192        const struct net_device_ops *ops;
 193        struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 194
 195        /* Don't do any rx activity if the dev_lock mutex is held
 196         * the dev_open/close paths use this to block netpoll activity
 197         * while changing device state
 198         */
 199        if (down_trylock(&ni->dev_lock))
 200                return;
 201
 202        if (!netif_running(dev)) {
 203                up(&ni->dev_lock);
 204                return;
 205        }
 206
 207        ops = dev->netdev_ops;
 208        if (!ops->ndo_poll_controller) {
 209                up(&ni->dev_lock);
 210                return;
 211        }
 212
 213        /* Process pending work on NIC */
 214        ops->ndo_poll_controller(dev);
 215
 216        poll_napi(dev);
 217
 218        up(&ni->dev_lock);
 219
 220        zap_completion_queue();
 221}
 222
 223void netpoll_poll_disable(struct net_device *dev)
 224{
 225        struct netpoll_info *ni;
 226        int idx;
 227        might_sleep();
 228        idx = srcu_read_lock(&netpoll_srcu);
 229        ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 230        if (ni)
 231                down(&ni->dev_lock);
 232        srcu_read_unlock(&netpoll_srcu, idx);
 233}
 234EXPORT_SYMBOL(netpoll_poll_disable);
 235
 236void netpoll_poll_enable(struct net_device *dev)
 237{
 238        struct netpoll_info *ni;
 239        rcu_read_lock();
 240        ni = rcu_dereference(dev->npinfo);
 241        if (ni)
 242                up(&ni->dev_lock);
 243        rcu_read_unlock();
 244}
 245EXPORT_SYMBOL(netpoll_poll_enable);
 246
 247static void refill_skbs(void)
 248{
 249        struct sk_buff *skb;
 250        unsigned long flags;
 251
 252        spin_lock_irqsave(&skb_pool.lock, flags);
 253        while (skb_pool.qlen < MAX_SKBS) {
 254                skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 255                if (!skb)
 256                        break;
 257
 258                __skb_queue_tail(&skb_pool, skb);
 259        }
 260        spin_unlock_irqrestore(&skb_pool.lock, flags);
 261}
 262
 263static void zap_completion_queue(void)
 264{
 265        unsigned long flags;
 266        struct softnet_data *sd = &get_cpu_var(softnet_data);
 267
 268        if (sd->completion_queue) {
 269                struct sk_buff *clist;
 270
 271                local_irq_save(flags);
 272                clist = sd->completion_queue;
 273                sd->completion_queue = NULL;
 274                local_irq_restore(flags);
 275
 276                while (clist != NULL) {
 277                        struct sk_buff *skb = clist;
 278                        clist = clist->next;
 279                        if (!skb_irq_freeable(skb)) {
 280                                refcount_set(&skb->users, 1);
 281                                dev_kfree_skb_any(skb); /* put this one back */
 282                        } else {
 283                                __kfree_skb(skb);
 284                        }
 285                }
 286        }
 287
 288        put_cpu_var(softnet_data);
 289}
 290
 291static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 292{
 293        int count = 0;
 294        struct sk_buff *skb;
 295
 296        zap_completion_queue();
 297        refill_skbs();
 298repeat:
 299
 300        skb = alloc_skb(len, GFP_ATOMIC);
 301        if (!skb)
 302                skb = skb_dequeue(&skb_pool);
 303
 304        if (!skb) {
 305                if (++count < 10) {
 306                        netpoll_poll_dev(np->dev);
 307                        goto repeat;
 308                }
 309                return NULL;
 310        }
 311
 312        refcount_set(&skb->users, 1);
 313        skb_reserve(skb, reserve);
 314        return skb;
 315}
 316
 317static int netpoll_owner_active(struct net_device *dev)
 318{
 319        struct napi_struct *napi;
 320
 321        list_for_each_entry(napi, &dev->napi_list, dev_list) {
 322                if (napi->poll_owner == smp_processor_id())
 323                        return 1;
 324        }
 325        return 0;
 326}
 327
 328/* call with IRQ disabled */
 329void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 330                             struct net_device *dev)
 331{
 332        int status = NETDEV_TX_BUSY;
 333        unsigned long tries;
 334        /* It is up to the caller to keep npinfo alive. */
 335        struct netpoll_info *npinfo;
 336
 337        lockdep_assert_irqs_disabled();
 338
 339        npinfo = rcu_dereference_bh(np->dev->npinfo);
 340        if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 341                dev_kfree_skb_irq(skb);
 342                return;
 343        }
 344
 345        /* don't get messages out of order, and no recursion */
 346        if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 347                struct netdev_queue *txq;
 348
 349                txq = netdev_pick_tx(dev, skb, NULL);
 350
 351                /* try until next clock tick */
 352                for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 353                     tries > 0; --tries) {
 354                        if (HARD_TX_TRYLOCK(dev, txq)) {
 355                                if (!netif_xmit_stopped(txq))
 356                                        status = netpoll_start_xmit(skb, dev, txq);
 357
 358                                HARD_TX_UNLOCK(dev, txq);
 359
 360                                if (status == NETDEV_TX_OK)
 361                                        break;
 362
 363                        }
 364
 365                        /* tickle device maybe there is some cleanup */
 366                        netpoll_poll_dev(np->dev);
 367
 368                        udelay(USEC_PER_POLL);
 369                }
 370
 371                WARN_ONCE(!irqs_disabled(),
 372                        "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 373                        dev->name, dev->netdev_ops->ndo_start_xmit);
 374
 375        }
 376
 377        if (status != NETDEV_TX_OK) {
 378                skb_queue_tail(&npinfo->txq, skb);
 379                schedule_delayed_work(&npinfo->tx_work,0);
 380        }
 381}
 382EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 383
 384void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 385{
 386        int total_len, ip_len, udp_len;
 387        struct sk_buff *skb;
 388        struct udphdr *udph;
 389        struct iphdr *iph;
 390        struct ethhdr *eth;
 391        static atomic_t ip_ident;
 392        struct ipv6hdr *ip6h;
 393
 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                put_unaligned(0x60, (unsigned char *)ip6h);
 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                put_unaligned(0x45, (unsigned char *)iph);
 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}
 485EXPORT_SYMBOL(netpoll_send_udp);
 486
 487void 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}
 502EXPORT_SYMBOL(netpoll_print_options);
 503
 504static 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
 524int 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}
 604EXPORT_SYMBOL(netpoll_parse_options);
 605
 606int __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        INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
 615
 616        if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 617            !ndev->netdev_ops->ndo_poll_controller) {
 618                np_err(np, "%s doesn't support polling, aborting\n",
 619                       np->dev_name);
 620                err = -ENOTSUPP;
 621                goto out;
 622        }
 623
 624        if (!ndev->npinfo) {
 625                npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 626                if (!npinfo) {
 627                        err = -ENOMEM;
 628                        goto out;
 629                }
 630
 631                sema_init(&npinfo->dev_lock, 1);
 632                skb_queue_head_init(&npinfo->txq);
 633                INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 634
 635                refcount_set(&npinfo->refcnt, 1);
 636
 637                ops = np->dev->netdev_ops;
 638                if (ops->ndo_netpoll_setup) {
 639                        err = ops->ndo_netpoll_setup(ndev, npinfo);
 640                        if (err)
 641                                goto free_npinfo;
 642                }
 643        } else {
 644                npinfo = rtnl_dereference(ndev->npinfo);
 645                refcount_inc(&npinfo->refcnt);
 646        }
 647
 648        npinfo->netpoll = np;
 649
 650        /* last thing to do is link it to the net device structure */
 651        rcu_assign_pointer(ndev->npinfo, npinfo);
 652
 653        return 0;
 654
 655free_npinfo:
 656        kfree(npinfo);
 657out:
 658        return err;
 659}
 660EXPORT_SYMBOL_GPL(__netpoll_setup);
 661
 662int netpoll_setup(struct netpoll *np)
 663{
 664        struct net_device *ndev = NULL;
 665        struct in_device *in_dev;
 666        int err;
 667
 668        rtnl_lock();
 669        if (np->dev_name[0]) {
 670                struct net *net = current->nsproxy->net_ns;
 671                ndev = __dev_get_by_name(net, np->dev_name);
 672        }
 673        if (!ndev) {
 674                np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 675                err = -ENODEV;
 676                goto unlock;
 677        }
 678        dev_hold(ndev);
 679
 680        if (netdev_master_upper_dev_get(ndev)) {
 681                np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 682                err = -EBUSY;
 683                goto put;
 684        }
 685
 686        if (!netif_running(ndev)) {
 687                unsigned long atmost, atleast;
 688
 689                np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 690
 691                err = dev_open(ndev);
 692
 693                if (err) {
 694                        np_err(np, "failed to open %s\n", ndev->name);
 695                        goto put;
 696                }
 697
 698                rtnl_unlock();
 699                atleast = jiffies + HZ/10;
 700                atmost = jiffies + carrier_timeout * HZ;
 701                while (!netif_carrier_ok(ndev)) {
 702                        if (time_after(jiffies, atmost)) {
 703                                np_notice(np, "timeout waiting for carrier\n");
 704                                break;
 705                        }
 706                        msleep(1);
 707                }
 708
 709                /* If carrier appears to come up instantly, we don't
 710                 * trust it and pause so that we don't pump all our
 711                 * queued console messages into the bitbucket.
 712                 */
 713
 714                if (time_before(jiffies, atleast)) {
 715                        np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 716                        msleep(4000);
 717                }
 718                rtnl_lock();
 719        }
 720
 721        if (!np->local_ip.ip) {
 722                if (!np->ipv6) {
 723                        in_dev = __in_dev_get_rtnl(ndev);
 724
 725                        if (!in_dev || !in_dev->ifa_list) {
 726                                np_err(np, "no IP address for %s, aborting\n",
 727                                       np->dev_name);
 728                                err = -EDESTADDRREQ;
 729                                goto put;
 730                        }
 731
 732                        np->local_ip.ip = in_dev->ifa_list->ifa_local;
 733                        np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 734                } else {
 735#if IS_ENABLED(CONFIG_IPV6)
 736                        struct inet6_dev *idev;
 737
 738                        err = -EDESTADDRREQ;
 739                        idev = __in6_dev_get(ndev);
 740                        if (idev) {
 741                                struct inet6_ifaddr *ifp;
 742
 743                                read_lock_bh(&idev->lock);
 744                                list_for_each_entry(ifp, &idev->addr_list, if_list) {
 745                                        if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
 746                                                continue;
 747                                        np->local_ip.in6 = ifp->addr;
 748                                        err = 0;
 749                                        break;
 750                                }
 751                                read_unlock_bh(&idev->lock);
 752                        }
 753                        if (err) {
 754                                np_err(np, "no IPv6 address for %s, aborting\n",
 755                                       np->dev_name);
 756                                goto put;
 757                        } else
 758                                np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 759#else
 760                        np_err(np, "IPv6 is not supported %s, aborting\n",
 761                               np->dev_name);
 762                        err = -EINVAL;
 763                        goto put;
 764#endif
 765                }
 766        }
 767
 768        /* fill up the skb queue */
 769        refill_skbs();
 770
 771        err = __netpoll_setup(np, ndev);
 772        if (err)
 773                goto put;
 774
 775        rtnl_unlock();
 776        return 0;
 777
 778put:
 779        dev_put(ndev);
 780unlock:
 781        rtnl_unlock();
 782        return err;
 783}
 784EXPORT_SYMBOL(netpoll_setup);
 785
 786static int __init netpoll_init(void)
 787{
 788        skb_queue_head_init(&skb_pool);
 789        return 0;
 790}
 791core_initcall(netpoll_init);
 792
 793static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 794{
 795        struct netpoll_info *npinfo =
 796                        container_of(rcu_head, struct netpoll_info, rcu);
 797
 798        skb_queue_purge(&npinfo->txq);
 799
 800        /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 801        cancel_delayed_work(&npinfo->tx_work);
 802
 803        /* clean after last, unfinished work */
 804        __skb_queue_purge(&npinfo->txq);
 805        /* now cancel it again */
 806        cancel_delayed_work(&npinfo->tx_work);
 807        kfree(npinfo);
 808}
 809
 810void __netpoll_cleanup(struct netpoll *np)
 811{
 812        struct netpoll_info *npinfo;
 813
 814        /* rtnl_dereference would be preferable here but
 815         * rcu_cleanup_netpoll path can put us in here safely without
 816         * holding the rtnl, so plain rcu_dereference it is
 817         */
 818        npinfo = rtnl_dereference(np->dev->npinfo);
 819        if (!npinfo)
 820                return;
 821
 822        synchronize_srcu(&netpoll_srcu);
 823
 824        if (refcount_dec_and_test(&npinfo->refcnt)) {
 825                const struct net_device_ops *ops;
 826
 827                ops = np->dev->netdev_ops;
 828                if (ops->ndo_netpoll_cleanup)
 829                        ops->ndo_netpoll_cleanup(np->dev);
 830
 831                RCU_INIT_POINTER(np->dev->npinfo, NULL);
 832                call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
 833        } else
 834                RCU_INIT_POINTER(np->dev->npinfo, NULL);
 835}
 836EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 837
 838static void netpoll_async_cleanup(struct work_struct *work)
 839{
 840        struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
 841
 842        rtnl_lock();
 843        __netpoll_cleanup(np);
 844        rtnl_unlock();
 845        kfree(np);
 846}
 847
 848void __netpoll_free_async(struct netpoll *np)
 849{
 850        schedule_work(&np->cleanup_work);
 851}
 852EXPORT_SYMBOL_GPL(__netpoll_free_async);
 853
 854void netpoll_cleanup(struct netpoll *np)
 855{
 856        rtnl_lock();
 857        if (!np->dev)
 858                goto out;
 859        __netpoll_cleanup(np);
 860        dev_put(np->dev);
 861        np->dev = NULL;
 862out:
 863        rtnl_unlock();
 864}
 865EXPORT_SYMBOL(netpoll_cleanup);
 866