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 #include <linux/moduleparam.h>
  13 #include <linux/netdevice.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/string.h>
  16 #include <linux/if_arp.h>
  17 #include <linux/inetdevice.h>
  18 #include <linux/inet.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/netpoll.h>
  21 #include <linux/sched.h>
  22 #include <linux/delay.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/workqueue.h>
  25 #include <linux/slab.h>
  26 #include <net/tcp.h>
  27 #include <net/udp.h>
  28 #include <asm/unaligned.h>
  29 #include <trace/events/napi.h>
  30
  31 /*
  32  * We maintain a small pool of fully-sized skbs, to make sure the
  33  * message gets out even in extreme OOM situations.
  34  */
  35
  36 #define MAX_UDP_CHUNK 1460
  37 #define MAX_SKBS 32
  38
  39 static struct sk_buff_head skb_pool;
  40
  41 static atomic_t trapped;
  42
  43 #define USEC_PER_POLL   50
  44 #define NETPOLL_RX_ENABLED  1
  45 #define NETPOLL_RX_DROP     2
  46
  47 #define MAX_SKB_SIZE \
  48                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  49                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  50
  51 static void zap_completion_queue(void);
  52 static void arp_reply(struct sk_buff *skb);
  53
  54 static unsigned int carrier_timeout = 4;
  55 module_param(carrier_timeout, uint, 0644);
  56
  57 static void queue_process(struct work_struct *work)
  58 {
  59         struct netpoll_info *npinfo =
  60                 container_of(work, struct netpoll_info, tx_work.work);
  61         struct sk_buff *skb;
  62         unsigned long flags;
  63
  64         while ((skb = skb_dequeue(&npinfo->txq))) {
  65                 struct net_device *dev = skb->dev;
  66                 const struct net_device_ops *ops = dev->netdev_ops;
  67                 struct netdev_queue *txq;
  68
  69                 if (!netif_device_present(dev) || !netif_running(dev)) {
  70                         __kfree_skb(skb);
  71                         continue;
  72                 }
  73
  74                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  75
  76                 local_irq_save(flags);
  77                 __netif_tx_lock(txq, smp_processor_id());
  78                 if (netif_tx_queue_frozen_or_stopped(txq) ||
  79                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  80                         skb_queue_head(&npinfo->txq, skb);
  81                         __netif_tx_unlock(txq);
  82                         local_irq_restore(flags);
  83
  84                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  85                         return;
  86                 }
  87                 __netif_tx_unlock(txq);
  88                 local_irq_restore(flags);
  89         }
  90 }
  91
  92 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  93                             unsigned short ulen, __be32 saddr, __be32 daddr)
  94 {
  95         __wsum psum;
  96
  97         if (uh->check == 0 || skb_csum_unnecessary(skb))
  98                 return 0;
  99
 100         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 101
 102         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 103             !csum_fold(csum_add(psum, skb->csum)))
 104                 return 0;
 105
 106         skb->csum = psum;
 107
 108         return __skb_checksum_complete(skb);
 109 }
 110
 111 /*
 112  * Check whether delayed processing was scheduled for our NIC. If so,
 113  * we attempt to grab the poll lock and use ->poll() to pump the card.
 114  * If this fails, either we've recursed in ->poll() or it's already
 115  * running on another CPU.
 116  *
 117  * Note: we don't mask interrupts with this lock because we're using
 118  * trylock here and interrupts are already disabled in the softirq
 119  * case. Further, we test the poll_owner to avoid recursion on UP
 120  * systems where the lock doesn't exist.
 121  *
 122  * In cases where there is bi-directional communications, reading only
 123  * one message at a time can lead to packets being dropped by the
 124  * network adapter, forcing superfluous retries and possibly timeouts.
 125  * Thus, we set our budget to greater than 1.
 126  */
 127 static int poll_one_napi(struct netpoll_info *npinfo,
 128                          struct napi_struct *napi, int budget)
 129 {
 130         int work;
 131
 132         /* net_rx_action's ->poll() invocations and our's are
 133          * synchronized by this test which is only made while
 134          * holding the napi->poll_lock.
 135          */
 136         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 137                 return budget;
 138
 139         npinfo->rx_flags |= NETPOLL_RX_DROP;
 140         atomic_inc(&trapped);
 141         set_bit(NAPI_STATE_NPSVC, &napi->state);
 142
 143         work = napi->poll(napi, budget);
 144         trace_napi_poll(napi);
 145
 146         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 147         atomic_dec(&trapped);
 148         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 149
 150         return budget - work;
 151 }
 152
 153 static void poll_napi(struct net_device *dev)
 154 {
 155         struct napi_struct *napi;
 156         int budget = 16;
 157
 158         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 159                 if (napi->poll_owner != smp_processor_id() &&
 160                     spin_trylock(&napi->poll_lock)) {
 161                         budget = poll_one_napi(dev->npinfo, napi, budget);
 162                         spin_unlock(&napi->poll_lock);
 163
 164                         if (!budget)
 165                                 break;
 166                 }
 167         }
 168 }
 169
 170 static void service_arp_queue(struct netpoll_info *npi)
 171 {
 172         if (npi) {
 173                 struct sk_buff *skb;
 174
 175                 while ((skb = skb_dequeue(&npi->arp_tx)))
 176                         arp_reply(skb);
 177         }
 178 }
 179
 180 static void netpoll_poll_dev(struct net_device *dev)
 181 {
 182         const struct net_device_ops *ops;
 183
 184         if (!dev || !netif_running(dev))
 185                 return;
 186
 187         ops = dev->netdev_ops;
 188         if (!ops->ndo_poll_controller)
 189                 return;
 190
 191         /* Process pending work on NIC */
 192         ops->ndo_poll_controller(dev);
 193
 194         poll_napi(dev);
 195
 196         if (dev->priv_flags & IFF_SLAVE) {
 197                 if (dev->npinfo) {
 198                         struct net_device *bond_dev = dev->master;
 199                         struct sk_buff *skb;
 200                         while ((skb = skb_dequeue(&dev->npinfo->arp_tx))) {
 201                                 skb->dev = bond_dev;
 202                                 skb_queue_tail(&bond_dev->npinfo->arp_tx, skb);
 203                         }
 204                 }
 205         }
 206
 207         service_arp_queue(dev->npinfo);
 208
 209         zap_completion_queue();
 210 }
 211
 212 static void refill_skbs(void)
 213 {
 214         struct sk_buff *skb;
 215         unsigned long flags;
 216
 217         spin_lock_irqsave(&skb_pool.lock, flags);
 218         while (skb_pool.qlen < MAX_SKBS) {
 219                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 220                 if (!skb)
 221                         break;
 222
 223                 __skb_queue_tail(&skb_pool, skb);
 224         }
 225         spin_unlock_irqrestore(&skb_pool.lock, flags);
 226 }
 227
 228 static void zap_completion_queue(void)
 229 {
 230         unsigned long flags;
 231         struct softnet_data *sd = &get_cpu_var(softnet_data);
 232
 233         if (sd->completion_queue) {
 234                 struct sk_buff *clist;
 235
 236                 local_irq_save(flags);
 237                 clist = sd->completion_queue;
 238                 sd->completion_queue = NULL;
 239                 local_irq_restore(flags);
 240
 241                 while (clist != NULL) {
 242                         struct sk_buff *skb = clist;
 243                         clist = clist->next;
 244                         if (skb->destructor) {
 245                                 atomic_inc(&skb->users);
 246                                 dev_kfree_skb_any(skb); /* put this one back */
 247                         } else {
 248                                 __kfree_skb(skb);
 249                         }
 250                 }
 251         }
 252
 253         put_cpu_var(softnet_data);
 254 }
 255
 256 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 257 {
 258         int count = 0;
 259         struct sk_buff *skb;
 260
 261         zap_completion_queue();
 262         refill_skbs();
 263 repeat:
 264
 265         skb = alloc_skb(len, GFP_ATOMIC);
 266         if (!skb)
 267                 skb = skb_dequeue(&skb_pool);
 268
 269         if (!skb) {
 270                 if (++count < 10) {
 271                         netpoll_poll_dev(np->dev);
 272                         goto repeat;
 273                 }
 274                 return NULL;
 275         }
 276
 277         atomic_set(&skb->users, 1);
 278         skb_reserve(skb, reserve);
 279         return skb;
 280 }
 281
 282 static int netpoll_owner_active(struct net_device *dev)
 283 {
 284         struct napi_struct *napi;
 285
 286         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 287                 if (napi->poll_owner == smp_processor_id())
 288                         return 1;
 289         }
 290         return 0;
 291 }
 292
 293 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 294                              struct net_device *dev)
 295 {
 296         int status = NETDEV_TX_BUSY;
 297         unsigned long tries;
 298         const struct net_device_ops *ops = dev->netdev_ops;
 299         /* It is up to the caller to keep npinfo alive. */
 300         struct netpoll_info *npinfo = np->dev->npinfo;
 301
 302         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 303                 __kfree_skb(skb);
 304                 return;
 305         }
 306
 307         /* don't get messages out of order, and no recursion */
 308         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 309                 struct netdev_queue *txq;
 310                 unsigned long flags;
 311
 312                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 313
 314                 local_irq_save(flags);
 315                 /* try until next clock tick */
 316                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 317                      tries > 0; --tries) {
 318                         if (__netif_tx_trylock(txq)) {
 319                                 if (!netif_tx_queue_stopped(txq)) {
 320                                         status = ops->ndo_start_xmit(skb, dev);
 321                                         if (status == NETDEV_TX_OK)
 322                                                 txq_trans_update(txq);
 323                                 }
 324                                 __netif_tx_unlock(txq);
 325
 326                                 if (status == NETDEV_TX_OK)
 327                                         break;
 328
 329                         }
 330
 331                         /* tickle device maybe there is some cleanup */
 332                         netpoll_poll_dev(np->dev);
 333
 334                         udelay(USEC_PER_POLL);
 335                 }
 336
 337                 WARN_ONCE(!irqs_disabled(),
 338                         "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
 339                         dev->name, ops->ndo_start_xmit);
 340
 341                 local_irq_restore(flags);
 342         }
 343
 344         if (status != NETDEV_TX_OK) {
 345                 skb_queue_tail(&npinfo->txq, skb);
 346                 schedule_delayed_work(&npinfo->tx_work,0);
 347         }
 348 }
 349 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 350
 351 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 352 {
 353         int total_len, eth_len, ip_len, udp_len;
 354         struct sk_buff *skb;
 355         struct udphdr *udph;
 356         struct iphdr *iph;
 357         struct ethhdr *eth;
 358
 359         udp_len = len + sizeof(*udph);
 360         ip_len = eth_len = udp_len + sizeof(*iph);
 361         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 362
 363         skb = find_skb(np, total_len, total_len - len);
 364         if (!skb)
 365                 return;
 366
 367         skb_copy_to_linear_data(skb, msg, len);
 368         skb->len += len;
 369
 370         skb_push(skb, sizeof(*udph));
 371         skb_reset_transport_header(skb);
 372         udph = udp_hdr(skb);
 373         udph->source = htons(np->local_port);
 374         udph->dest = htons(np->remote_port);
 375         udph->len = htons(udp_len);
 376         udph->check = 0;
 377         udph->check = csum_tcpudp_magic(np->local_ip,
 378                                         np->remote_ip,
 379                                         udp_len, IPPROTO_UDP,
 380                                         csum_partial(udph, udp_len, 0));
 381         if (udph->check == 0)
 382                 udph->check = CSUM_MANGLED_0;
 383
 384         skb_push(skb, sizeof(*iph));
 385         skb_reset_network_header(skb);
 386         iph = ip_hdr(skb);
 387
 388         /* iph->version = 4; iph->ihl = 5; */
 389         put_unaligned(0x45, (unsigned char *)iph);
 390         iph->tos      = 0;
 391         put_unaligned(htons(ip_len), &(iph->tot_len));
 392         iph->id       = 0;
 393         iph->frag_off = 0;
 394         iph->ttl      = 64;
 395         iph->protocol = IPPROTO_UDP;
 396         iph->check    = 0;
 397         put_unaligned(np->local_ip, &(iph->saddr));
 398         put_unaligned(np->remote_ip, &(iph->daddr));
 399         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 400
 401         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 402         skb_reset_mac_header(skb);
 403         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 404         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 405         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 406
 407         skb->dev = np->dev;
 408
 409         netpoll_send_skb(np, skb);
 410 }
 411 EXPORT_SYMBOL(netpoll_send_udp);
 412
 413 static void arp_reply(struct sk_buff *skb)
 414 {
 415         struct netpoll_info *npinfo = skb->dev->npinfo;
 416         struct arphdr *arp;
 417         unsigned char *arp_ptr;
 418         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 419         __be32 sip, tip;
 420         unsigned char *sha;
 421         struct sk_buff *send_skb;
 422         struct netpoll *np, *tmp;
 423         unsigned long flags;
 424         int hits = 0;
 425
 426         if (list_empty(&npinfo->rx_np))
 427                 return;
 428
 429         /* Before checking the packet, we do some early
 430            inspection whether this is interesting at all */
 431         spin_lock_irqsave(&npinfo->rx_lock, flags);
 432         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 433                 if (np->dev == skb->dev)
 434                         hits++;
 435         }
 436         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 437
 438         /* No netpoll struct is using this dev */
 439         if (!hits)
 440                 return;
 441
 442         /* No arp on this interface */
 443         if (skb->dev->flags & IFF_NOARP)
 444                 return;
 445
 446         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 447                 return;
 448
 449         skb_reset_network_header(skb);
 450         skb_reset_transport_header(skb);
 451         arp = arp_hdr(skb);
 452
 453         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 454              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 455             arp->ar_pro != htons(ETH_P_IP) ||
 456             arp->ar_op != htons(ARPOP_REQUEST))
 457                 return;
 458
 459         arp_ptr = (unsigned char *)(arp+1);
 460         /* save the location of the src hw addr */
 461         sha = arp_ptr;
 462         arp_ptr += skb->dev->addr_len;
 463         memcpy(&sip, arp_ptr, 4);
 464         arp_ptr += 4;
 465         /* If we actually cared about dst hw addr,
 466            it would get copied here */
 467         arp_ptr += skb->dev->addr_len;
 468         memcpy(&tip, arp_ptr, 4);
 469
 470         /* Should we ignore arp? */
 471         if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 472                 return;
 473
 474         size = arp_hdr_len(skb->dev);
 475
 476         spin_lock_irqsave(&npinfo->rx_lock, flags);
 477         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 478                 if (tip != np->local_ip)
 479                         continue;
 480
 481                 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 482                                     LL_RESERVED_SPACE(np->dev));
 483                 if (!send_skb)
 484                         continue;
 485
 486                 skb_reset_network_header(send_skb);
 487                 arp = (struct arphdr *) skb_put(send_skb, size);
 488                 send_skb->dev = skb->dev;
 489                 send_skb->protocol = htons(ETH_P_ARP);
 490
 491                 /* Fill the device header for the ARP frame */
 492                 if (dev_hard_header(send_skb, skb->dev, ptype,
 493                                     sha, np->dev->dev_addr,
 494                                     send_skb->len) < 0) {
 495                         kfree_skb(send_skb);
 496                         continue;
 497                 }
 498
 499                 /*
 500                  * Fill out the arp protocol part.
 501                  *
 502                  * we only support ethernet device type,
 503                  * which (according to RFC 1390) should
 504                  * always equal 1 (Ethernet).
 505                  */
 506
 507                 arp->ar_hrd = htons(np->dev->type);
 508                 arp->ar_pro = htons(ETH_P_IP);
 509                 arp->ar_hln = np->dev->addr_len;
 510                 arp->ar_pln = 4;
 511                 arp->ar_op = htons(type);
 512
 513                 arp_ptr = (unsigned char *)(arp + 1);
 514                 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 515                 arp_ptr += np->dev->addr_len;
 516                 memcpy(arp_ptr, &tip, 4);
 517                 arp_ptr += 4;
 518                 memcpy(arp_ptr, sha, np->dev->addr_len);
 519                 arp_ptr += np->dev->addr_len;
 520                 memcpy(arp_ptr, &sip, 4);
 521
 522                 netpoll_send_skb(np, send_skb);
 523
 524                 /* If there are several rx_hooks for the same address,
 525                    we're fine by sending a single reply */
 526                 break;
 527         }
 528         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 529 }
 530
 531 int __netpoll_rx(struct sk_buff *skb)
 532 {
 533         int proto, len, ulen;
 534         int hits = 0;
 535         const struct iphdr *iph;
 536         struct udphdr *uh;
 537         struct netpoll_info *npinfo = skb->dev->npinfo;
 538         struct netpoll *np, *tmp;
 539
 540         if (list_empty(&npinfo->rx_np))
 541                 goto out;
 542
 543         if (skb->dev->type != ARPHRD_ETHER)
 544                 goto out;
 545
 546         /* check if netpoll clients need ARP */
 547         if (skb->protocol == htons(ETH_P_ARP) &&
 548             atomic_read(&trapped)) {
 549                 skb_queue_tail(&npinfo->arp_tx, skb);
 550                 return 1;
 551         }
 552
 553         proto = ntohs(eth_hdr(skb)->h_proto);
 554         if (proto != ETH_P_IP)
 555                 goto out;
 556         if (skb->pkt_type == PACKET_OTHERHOST)
 557                 goto out;
 558         if (skb_shared(skb))
 559                 goto out;
 560
 561         iph = (struct iphdr *)skb->data;
 562         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 563                 goto out;
 564         if (iph->ihl < 5 || iph->version != 4)
 565                 goto out;
 566         if (!pskb_may_pull(skb, iph->ihl*4))
 567                 goto out;
 568         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 569                 goto out;
 570
 571         len = ntohs(iph->tot_len);
 572         if (skb->len < len || len < iph->ihl*4)
 573                 goto out;
 574
 575         /*
 576          * Our transport medium may have padded the buffer out.
 577          * Now We trim to the true length of the frame.
 578          */
 579         if (pskb_trim_rcsum(skb, len))
 580                 goto out;
 581
 582         if (iph->protocol != IPPROTO_UDP)
 583                 goto out;
 584
 585         len -= iph->ihl*4;
 586         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 587         ulen = ntohs(uh->len);
 588
 589         if (ulen != len)
 590                 goto out;
 591         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 592                 goto out;
 593
 594         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 595                 if (np->local_ip && np->local_ip != iph->daddr)
 596                         continue;
 597                 if (np->remote_ip && np->remote_ip != iph->saddr)
 598                         continue;
 599                 if (np->local_port && np->local_port != ntohs(uh->dest))
 600                         continue;
 601
 602                 np->rx_hook(np, ntohs(uh->source),
 603                                (char *)(uh+1),
 604                                ulen - sizeof(struct udphdr));
 605                 hits++;
 606         }
 607
 608         if (!hits)
 609                 goto out;
 610
 611         kfree_skb(skb);
 612         return 1;
 613
 614 out:
 615         if (atomic_read(&trapped)) {
 616                 kfree_skb(skb);
 617                 return 1;
 618         }
 619
 620         return 0;
 621 }
 622
 623 void netpoll_print_options(struct netpoll *np)
 624 {
 625         printk(KERN_INFO "%s: local port %d\n",
 626                          np->name, np->local_port);
 627         printk(KERN_INFO "%s: local IP %pI4\n",
 628                          np->name, &np->local_ip);
 629         printk(KERN_INFO "%s: interface '%s'\n",
 630                          np->name, np->dev_name);
 631         printk(KERN_INFO "%s: remote port %d\n",
 632                          np->name, np->remote_port);
 633         printk(KERN_INFO "%s: remote IP %pI4\n",
 634                          np->name, &np->remote_ip);
 635         printk(KERN_INFO "%s: remote ethernet address %pM\n",
 636                          np->name, np->remote_mac);
 637 }
 638 EXPORT_SYMBOL(netpoll_print_options);
 639
 640 int netpoll_parse_options(struct netpoll *np, char *opt)
 641 {
 642         char *cur=opt, *delim;
 643
 644         if (*cur != '@') {
 645                 if ((delim = strchr(cur, '@')) == NULL)
 646                         goto parse_failed;
 647                 *delim = 0;
 648                 np->local_port = simple_strtol(cur, NULL, 10);
 649                 cur = delim;
 650         }
 651         cur++;
 652
 653         if (*cur != '/') {
 654                 if ((delim = strchr(cur, '/')) == NULL)
 655                         goto parse_failed;
 656                 *delim = 0;
 657                 np->local_ip = in_aton(cur);
 658                 cur = delim;
 659         }
 660         cur++;
 661
 662         if (*cur != ',') {
 663                 /* parse out dev name */
 664                 if ((delim = strchr(cur, ',')) == NULL)
 665                         goto parse_failed;
 666                 *delim = 0;
 667                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 668                 cur = delim;
 669         }
 670         cur++;
 671
 672         if (*cur != '@') {
 673                 /* dst port */
 674                 if ((delim = strchr(cur, '@')) == NULL)
 675                         goto parse_failed;
 676                 *delim = 0;
 677                 if (*cur == ' ' || *cur == '\t')
 678                         printk(KERN_INFO "%s: warning: whitespace"
 679                                         "is not allowed\n", np->name);
 680                 np->remote_port = simple_strtol(cur, NULL, 10);
 681                 cur = delim;
 682         }
 683         cur++;
 684
 685         /* dst ip */
 686         if ((delim = strchr(cur, '/')) == NULL)
 687                 goto parse_failed;
 688         *delim = 0;
 689         np->remote_ip = in_aton(cur);
 690         cur = delim + 1;
 691
 692         if (*cur != 0) {
 693                 /* MAC address */
 694                 if (!mac_pton(cur, np->remote_mac))
 695                         goto parse_failed;
 696         }
 697
 698         netpoll_print_options(np);
 699
 700         return 0;
 701
 702  parse_failed:
 703         printk(KERN_INFO "%s: couldn't parse config at '%s'!\n",
 704                np->name, cur);
 705         return -1;
 706 }
 707 EXPORT_SYMBOL(netpoll_parse_options);
 708
 709 int __netpoll_setup(struct netpoll *np)
 710 {
 711         struct net_device *ndev = np->dev;
 712         struct netpoll_info *npinfo;
 713         const struct net_device_ops *ops;
 714         unsigned long flags;
 715         int err;
 716
 717         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 718             !ndev->netdev_ops->ndo_poll_controller) {
 719                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 720                        np->name, np->dev_name);
 721                 err = -ENOTSUPP;
 722                 goto out;
 723         }
 724
 725         if (!ndev->npinfo) {
 726                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 727                 if (!npinfo) {
 728                         err = -ENOMEM;
 729                         goto out;
 730                 }
 731
 732                 npinfo->rx_flags = 0;
 733                 INIT_LIST_HEAD(&npinfo->rx_np);
 734
 735                 spin_lock_init(&npinfo->rx_lock);
 736                 skb_queue_head_init(&npinfo->arp_tx);
 737                 skb_queue_head_init(&npinfo->txq);
 738                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 739
 740                 atomic_set(&npinfo->refcnt, 1);
 741
 742                 ops = np->dev->netdev_ops;
 743                 if (ops->ndo_netpoll_setup) {
 744                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 745                         if (err)
 746                                 goto free_npinfo;
 747                 }
 748         } else {
 749                 npinfo = ndev->npinfo;
 750                 atomic_inc(&npinfo->refcnt);
 751         }
 752
 753         npinfo->netpoll = np;
 754
 755         if (np->rx_hook) {
 756                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 757                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 758                 list_add_tail(&np->rx, &npinfo->rx_np);
 759                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 760         }
 761
 762         /* last thing to do is link it to the net device structure */
 763         rcu_assign_pointer(ndev->npinfo, npinfo);
 764
 765         return 0;
 766
 767 free_npinfo:
 768         kfree(npinfo);
 769 out:
 770         return err;
 771 }
 772 EXPORT_SYMBOL_GPL(__netpoll_setup);
 773
 774 int netpoll_setup(struct netpoll *np)
 775 {
 776         struct net_device *ndev = NULL;
 777         struct in_device *in_dev;
 778         int err;
 779
 780         if (np->dev_name)
 781                 ndev = dev_get_by_name(&init_net, np->dev_name);
 782         if (!ndev) {
 783                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 784                        np->name, np->dev_name);
 785                 return -ENODEV;
 786         }
 787
 788         if (ndev->master) {
 789                 printk(KERN_ERR "%s: %s is a slave device, aborting.\n",
 790                        np->name, np->dev_name);
 791                 err = -EBUSY;
 792                 goto put;
 793         }
 794
 795         if (!netif_running(ndev)) {
 796                 unsigned long atmost, atleast;
 797
 798                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 799                        np->name, np->dev_name);
 800
 801                 rtnl_lock();
 802                 err = dev_open(ndev);
 803                 rtnl_unlock();
 804
 805                 if (err) {
 806                         printk(KERN_ERR "%s: failed to open %s\n",
 807                                np->name, ndev->name);
 808                         goto put;
 809                 }
 810
 811                 atleast = jiffies + HZ/10;
 812                 atmost = jiffies + carrier_timeout * HZ;
 813                 while (!netif_carrier_ok(ndev)) {
 814                         if (time_after(jiffies, atmost)) {
 815                                 printk(KERN_NOTICE
 816                                        "%s: timeout waiting for carrier\n",
 817                                        np->name);
 818                                 break;
 819                         }
 820                         msleep(1);
 821                 }
 822
 823                 /* If carrier appears to come up instantly, we don't
 824                  * trust it and pause so that we don't pump all our
 825                  * queued console messages into the bitbucket.
 826                  */
 827
 828                 if (time_before(jiffies, atleast)) {
 829                         printk(KERN_NOTICE "%s: carrier detect appears"
 830                                " untrustworthy, waiting 4 seconds\n",
 831                                np->name);
 832                         msleep(4000);
 833                 }
 834         }
 835
 836         if (!np->local_ip) {
 837                 rcu_read_lock();
 838                 in_dev = __in_dev_get_rcu(ndev);
 839
 840                 if (!in_dev || !in_dev->ifa_list) {
 841                         rcu_read_unlock();
 842                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 843                                np->name, np->dev_name);
 844                         err = -EDESTADDRREQ;
 845                         goto put;
 846                 }
 847
 848                 np->local_ip = in_dev->ifa_list->ifa_local;
 849                 rcu_read_unlock();
 850                 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
 851         }
 852
 853         np->dev = ndev;
 854
 855         /* fill up the skb queue */
 856         refill_skbs();
 857
 858         rtnl_lock();
 859         err = __netpoll_setup(np);
 860         rtnl_unlock();
 861
 862         if (err)
 863                 goto put;
 864
 865         return 0;
 866
 867 put:
 868         dev_put(ndev);
 869         return err;
 870 }
 871 EXPORT_SYMBOL(netpoll_setup);
 872
 873 static int __init netpoll_init(void)
 874 {
 875         skb_queue_head_init(&skb_pool);
 876         return 0;
 877 }
 878 core_initcall(netpoll_init);
 879
 880 void __netpoll_cleanup(struct netpoll *np)
 881 {
 882         struct netpoll_info *npinfo;
 883         unsigned long flags;
 884
 885         npinfo = np->dev->npinfo;
 886         if (!npinfo)
 887                 return;
 888
 889         if (!list_empty(&npinfo->rx_np)) {
 890                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 891                 list_del(&np->rx);
 892                 if (list_empty(&npinfo->rx_np))
 893                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 894                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 895         }
 896
 897         if (atomic_dec_and_test(&npinfo->refcnt)) {
 898                 const struct net_device_ops *ops;
 899
 900                 ops = np->dev->netdev_ops;
 901                 if (ops->ndo_netpoll_cleanup)
 902                         ops->ndo_netpoll_cleanup(np->dev);
 903
 904                 rcu_assign_pointer(np->dev->npinfo, NULL);
 905
 906                 /* avoid racing with NAPI reading npinfo */
 907                 synchronize_rcu_bh();
 908
 909                 skb_queue_purge(&npinfo->arp_tx);
 910                 skb_queue_purge(&npinfo->txq);
 911                 cancel_delayed_work_sync(&npinfo->tx_work);
 912
 913                 /* clean after last, unfinished work */
 914                 __skb_queue_purge(&npinfo->txq);
 915                 kfree(npinfo);
 916         }
 917 }
 918 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 919
 920 void netpoll_cleanup(struct netpoll *np)
 921 {
 922         if (!np->dev)
 923                 return;
 924
 925         rtnl_lock();
 926         __netpoll_cleanup(np);
 927         rtnl_unlock();
 928
 929         dev_put(np->dev);
 930         np->dev = NULL;
 931 }
 932 EXPORT_SYMBOL(netpoll_cleanup);
 933
 934 int netpoll_trap(void)
 935 {
 936         return atomic_read(&trapped);
 937 }
 938 EXPORT_SYMBOL(netpoll_trap);
 939
 940 void netpoll_set_trap(int trap)
 941 {
 942         if (trap)
 943                 atomic_inc(&trapped);
 944         else
 945                 atomic_dec(&trapped);
 946 }
 947 EXPORT_SYMBOL(netpoll_set_trap);