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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 #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 <net/tcp.h>
  26 #include <net/udp.h>
  27 #include <asm/unaligned.h>
  28 #include <trace/events/napi.h>
  29
  30 /*
  31  * We maintain a small pool of fully-sized skbs, to make sure the
  32  * message gets out even in extreme OOM situations.
  33  */
  34
  35 #define MAX_UDP_CHUNK 1460
  36 #define MAX_SKBS 32
  37 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
  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_stopped(txq) ||
  79                     netif_tx_queue_frozen(txq) ||
  80                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  81                         skb_queue_head(&npinfo->txq, skb);
  82                         __netif_tx_unlock(txq);
  83                         local_irq_restore(flags);
  84
  85                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  86                         return;
  87                 }
  88                 __netif_tx_unlock(txq);
  89                 local_irq_restore(flags);
  90         }
  91 }
  92
  93 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  94                             unsigned short ulen, __be32 saddr, __be32 daddr)
  95 {
  96         __wsum psum;
  97
  98         if (uh->check == 0 || skb_csum_unnecessary(skb))
  99                 return 0;
 100
 101         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 102
 103         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 104             !csum_fold(csum_add(psum, skb->csum)))
 105                 return 0;
 106
 107         skb->csum = psum;
 108
 109         return __skb_checksum_complete(skb);
 110 }
 111
 112 /*
 113  * Check whether delayed processing was scheduled for our NIC. If so,
 114  * we attempt to grab the poll lock and use ->poll() to pump the card.
 115  * If this fails, either we've recursed in ->poll() or it's already
 116  * running on another CPU.
 117  *
 118  * Note: we don't mask interrupts with this lock because we're using
 119  * trylock here and interrupts are already disabled in the softirq
 120  * case. Further, we test the poll_owner to avoid recursion on UP
 121  * systems where the lock doesn't exist.
 122  *
 123  * In cases where there is bi-directional communications, reading only
 124  * one message at a time can lead to packets being dropped by the
 125  * network adapter, forcing superfluous retries and possibly timeouts.
 126  * Thus, we set our budget to greater than 1.
 127  */
 128 static int poll_one_napi(struct netpoll_info *npinfo,
 129                          struct napi_struct *napi, int budget)
 130 {
 131         int work;
 132
 133         /* net_rx_action's ->poll() invocations and our's are
 134          * synchronized by this test which is only made while
 135          * holding the napi->poll_lock.
 136          */
 137         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 138                 return budget;
 139
 140         npinfo->rx_flags |= NETPOLL_RX_DROP;
 141         atomic_inc(&trapped);
 142         set_bit(NAPI_STATE_NPSVC, &napi->state);
 143
 144         work = napi->poll(napi, budget);
 145         trace_napi_poll(napi);
 146
 147         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 148         atomic_dec(&trapped);
 149         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 150
 151         return budget - work;
 152 }
 153
 154 static void poll_napi(struct net_device *dev)
 155 {
 156         struct napi_struct *napi;
 157         int budget = 16;
 158
 159         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 160                 if (napi->poll_owner != smp_processor_id() &&
 161                     spin_trylock(&napi->poll_lock)) {
 162                         budget = poll_one_napi(dev->npinfo, napi, budget);
 163                         spin_unlock(&napi->poll_lock);
 164
 165                         if (!budget)
 166                                 break;
 167                 }
 168         }
 169 }
 170
 171 static void service_arp_queue(struct netpoll_info *npi)
 172 {
 173         if (npi) {
 174                 struct sk_buff *skb;
 175
 176                 while ((skb = skb_dequeue(&npi->arp_tx)))
 177                         arp_reply(skb);
 178         }
 179 }
 180
 181 void netpoll_poll(struct netpoll *np)
 182 {
 183         struct net_device *dev = np->dev;
 184         const struct net_device_ops *ops;
 185
 186         if (!dev || !netif_running(dev))
 187                 return;
 188
 189         ops = dev->netdev_ops;
 190         if (!ops->ndo_poll_controller)
 191                 return;
 192
 193         /* Process pending work on NIC */
 194         ops->ndo_poll_controller(dev);
 195
 196         poll_napi(dev);
 197
 198         service_arp_queue(dev->npinfo);
 199
 200         zap_completion_queue();
 201 }
 202
 203 static void refill_skbs(void)
 204 {
 205         struct sk_buff *skb;
 206         unsigned long flags;
 207
 208         spin_lock_irqsave(&skb_pool.lock, flags);
 209         while (skb_pool.qlen < MAX_SKBS) {
 210                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 211                 if (!skb)
 212                         break;
 213
 214                 __skb_queue_tail(&skb_pool, skb);
 215         }
 216         spin_unlock_irqrestore(&skb_pool.lock, flags);
 217 }
 218
 219 static void zap_completion_queue(void)
 220 {
 221         unsigned long flags;
 222         struct softnet_data *sd = &get_cpu_var(softnet_data);
 223
 224         if (sd->completion_queue) {
 225                 struct sk_buff *clist;
 226
 227                 local_irq_save(flags);
 228                 clist = sd->completion_queue;
 229                 sd->completion_queue = NULL;
 230                 local_irq_restore(flags);
 231
 232                 while (clist != NULL) {
 233                         struct sk_buff *skb = clist;
 234                         clist = clist->next;
 235                         if (skb->destructor) {
 236                                 atomic_inc(&skb->users);
 237                                 dev_kfree_skb_any(skb); /* put this one back */
 238                         } else {
 239                                 __kfree_skb(skb);
 240                         }
 241                 }
 242         }
 243
 244         put_cpu_var(softnet_data);
 245 }
 246
 247 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 248 {
 249         int count = 0;
 250         struct sk_buff *skb;
 251
 252         zap_completion_queue();
 253         refill_skbs();
 254 repeat:
 255
 256         skb = alloc_skb(len, GFP_ATOMIC);
 257         if (!skb)
 258                 skb = skb_dequeue(&skb_pool);
 259
 260         if (!skb) {
 261                 if (++count < 10) {
 262                         netpoll_poll(np);
 263                         goto repeat;
 264                 }
 265                 return NULL;
 266         }
 267
 268         atomic_set(&skb->users, 1);
 269         skb_reserve(skb, reserve);
 270         return skb;
 271 }
 272
 273 static int netpoll_owner_active(struct net_device *dev)
 274 {
 275         struct napi_struct *napi;
 276
 277         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 278                 if (napi->poll_owner == smp_processor_id())
 279                         return 1;
 280         }
 281         return 0;
 282 }
 283
 284 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 285 {
 286         int status = NETDEV_TX_BUSY;
 287         unsigned long tries;
 288         struct net_device *dev = np->dev;
 289         const struct net_device_ops *ops = dev->netdev_ops;
 290         struct netpoll_info *npinfo = np->dev->npinfo;
 291
 292         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 293                 __kfree_skb(skb);
 294                 return;
 295         }
 296
 297         /* don't get messages out of order, and no recursion */
 298         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 299                 struct netdev_queue *txq;
 300                 unsigned long flags;
 301
 302                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 303
 304                 local_irq_save(flags);
 305                 /* try until next clock tick */
 306                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 307                      tries > 0; --tries) {
 308                         if (__netif_tx_trylock(txq)) {
 309                                 if (!netif_tx_queue_stopped(txq)) {
 310                                         status = ops->ndo_start_xmit(skb, dev);
 311                                         if (status == NETDEV_TX_OK)
 312                                                 txq_trans_update(txq);
 313                                 }
 314                                 __netif_tx_unlock(txq);
 315
 316                                 if (status == NETDEV_TX_OK)
 317                                         break;
 318
 319                         }
 320
 321                         /* tickle device maybe there is some cleanup */
 322                         netpoll_poll(np);
 323
 324                         udelay(USEC_PER_POLL);
 325                 }
 326
 327                 WARN_ONCE(!irqs_disabled(),
 328                         "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
 329                         dev->name, ops->ndo_start_xmit);
 330
 331                 local_irq_restore(flags);
 332         }
 333
 334         if (status != NETDEV_TX_OK) {
 335                 skb_queue_tail(&npinfo->txq, skb);
 336                 schedule_delayed_work(&npinfo->tx_work,0);
 337         }
 338 }
 339
 340 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 341 {
 342         int total_len, eth_len, ip_len, udp_len;
 343         struct sk_buff *skb;
 344         struct udphdr *udph;
 345         struct iphdr *iph;
 346         struct ethhdr *eth;
 347
 348         udp_len = len + sizeof(*udph);
 349         ip_len = eth_len = udp_len + sizeof(*iph);
 350         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 351
 352         skb = find_skb(np, total_len, total_len - len);
 353         if (!skb)
 354                 return;
 355
 356         skb_copy_to_linear_data(skb, msg, len);
 357         skb->len += len;
 358
 359         skb_push(skb, sizeof(*udph));
 360         skb_reset_transport_header(skb);
 361         udph = udp_hdr(skb);
 362         udph->source = htons(np->local_port);
 363         udph->dest = htons(np->remote_port);
 364         udph->len = htons(udp_len);
 365         udph->check = 0;
 366         udph->check = csum_tcpudp_magic(np->local_ip,
 367                                         np->remote_ip,
 368                                         udp_len, IPPROTO_UDP,
 369                                         csum_partial(udph, udp_len, 0));
 370         if (udph->check == 0)
 371                 udph->check = CSUM_MANGLED_0;
 372
 373         skb_push(skb, sizeof(*iph));
 374         skb_reset_network_header(skb);
 375         iph = ip_hdr(skb);
 376
 377         /* iph->version = 4; iph->ihl = 5; */
 378         put_unaligned(0x45, (unsigned char *)iph);
 379         iph->tos      = 0;
 380         put_unaligned(htons(ip_len), &(iph->tot_len));
 381         iph->id       = 0;
 382         iph->frag_off = 0;
 383         iph->ttl      = 64;
 384         iph->protocol = IPPROTO_UDP;
 385         iph->check    = 0;
 386         put_unaligned(np->local_ip, &(iph->saddr));
 387         put_unaligned(np->remote_ip, &(iph->daddr));
 388         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 389
 390         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 391         skb_reset_mac_header(skb);
 392         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 393         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 394         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 395
 396         skb->dev = np->dev;
 397
 398         netpoll_send_skb(np, skb);
 399 }
 400
 401 static void arp_reply(struct sk_buff *skb)
 402 {
 403         struct netpoll_info *npinfo = skb->dev->npinfo;
 404         struct arphdr *arp;
 405         unsigned char *arp_ptr;
 406         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 407         __be32 sip, tip;
 408         unsigned char *sha;
 409         struct sk_buff *send_skb;
 410         struct netpoll *np, *tmp;
 411         unsigned long flags;
 412         int hits = 0;
 413
 414         if (list_empty(&npinfo->rx_np))
 415                 return;
 416
 417         /* Before checking the packet, we do some early
 418            inspection whether this is interesting at all */
 419         spin_lock_irqsave(&npinfo->rx_lock, flags);
 420         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 421                 if (np->dev == skb->dev)
 422                         hits++;
 423         }
 424         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 425
 426         /* No netpoll struct is using this dev */
 427         if (!hits)
 428                 return;
 429
 430         /* No arp on this interface */
 431         if (skb->dev->flags & IFF_NOARP)
 432                 return;
 433
 434         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 435                 return;
 436
 437         skb_reset_network_header(skb);
 438         skb_reset_transport_header(skb);
 439         arp = arp_hdr(skb);
 440
 441         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 442              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 443             arp->ar_pro != htons(ETH_P_IP) ||
 444             arp->ar_op != htons(ARPOP_REQUEST))
 445                 return;
 446
 447         arp_ptr = (unsigned char *)(arp+1);
 448         /* save the location of the src hw addr */
 449         sha = arp_ptr;
 450         arp_ptr += skb->dev->addr_len;
 451         memcpy(&sip, arp_ptr, 4);
 452         arp_ptr += 4;
 453         /* If we actually cared about dst hw addr,
 454            it would get copied here */
 455         arp_ptr += skb->dev->addr_len;
 456         memcpy(&tip, arp_ptr, 4);
 457
 458         /* Should we ignore arp? */
 459         if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 460                 return;
 461
 462         size = arp_hdr_len(skb->dev);
 463
 464         spin_lock_irqsave(&npinfo->rx_lock, flags);
 465         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 466                 if (tip != np->local_ip)
 467                         continue;
 468
 469                 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 470                                     LL_RESERVED_SPACE(np->dev));
 471                 if (!send_skb)
 472                         continue;
 473
 474                 skb_reset_network_header(send_skb);
 475                 arp = (struct arphdr *) skb_put(send_skb, size);
 476                 send_skb->dev = skb->dev;
 477                 send_skb->protocol = htons(ETH_P_ARP);
 478
 479                 /* Fill the device header for the ARP frame */
 480                 if (dev_hard_header(send_skb, skb->dev, ptype,
 481                                     sha, np->dev->dev_addr,
 482                                     send_skb->len) < 0) {
 483                         kfree_skb(send_skb);
 484                         continue;
 485                 }
 486
 487                 /*
 488                  * Fill out the arp protocol part.
 489                  *
 490                  * we only support ethernet device type,
 491                  * which (according to RFC 1390) should
 492                  * always equal 1 (Ethernet).
 493                  */
 494
 495                 arp->ar_hrd = htons(np->dev->type);
 496                 arp->ar_pro = htons(ETH_P_IP);
 497                 arp->ar_hln = np->dev->addr_len;
 498                 arp->ar_pln = 4;
 499                 arp->ar_op = htons(type);
 500
 501                 arp_ptr = (unsigned char *)(arp + 1);
 502                 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 503                 arp_ptr += np->dev->addr_len;
 504                 memcpy(arp_ptr, &tip, 4);
 505                 arp_ptr += 4;
 506                 memcpy(arp_ptr, sha, np->dev->addr_len);
 507                 arp_ptr += np->dev->addr_len;
 508                 memcpy(arp_ptr, &sip, 4);
 509
 510                 netpoll_send_skb(np, send_skb);
 511
 512                 /* If there are several rx_hooks for the same address,
 513                    we're fine by sending a single reply */
 514                 break;
 515         }
 516         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 517 }
 518
 519 int __netpoll_rx(struct sk_buff *skb)
 520 {
 521         int proto, len, ulen;
 522         int hits = 0;
 523         struct iphdr *iph;
 524         struct udphdr *uh;
 525         struct netpoll_info *npinfo = skb->dev->npinfo;
 526         struct netpoll *np, *tmp;
 527
 528         if (list_empty(&npinfo->rx_np))
 529                 goto out;
 530
 531         if (skb->dev->type != ARPHRD_ETHER)
 532                 goto out;
 533
 534         /* check if netpoll clients need ARP */
 535         if (skb->protocol == htons(ETH_P_ARP) &&
 536             atomic_read(&trapped)) {
 537                 skb_queue_tail(&npinfo->arp_tx, skb);
 538                 return 1;
 539         }
 540
 541         proto = ntohs(eth_hdr(skb)->h_proto);
 542         if (proto != ETH_P_IP)
 543                 goto out;
 544         if (skb->pkt_type == PACKET_OTHERHOST)
 545                 goto out;
 546         if (skb_shared(skb))
 547                 goto out;
 548
 549         iph = (struct iphdr *)skb->data;
 550         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 551                 goto out;
 552         if (iph->ihl < 5 || iph->version != 4)
 553                 goto out;
 554         if (!pskb_may_pull(skb, iph->ihl*4))
 555                 goto out;
 556         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 557                 goto out;
 558
 559         len = ntohs(iph->tot_len);
 560         if (skb->len < len || len < iph->ihl*4)
 561                 goto out;
 562
 563         /*
 564          * Our transport medium may have padded the buffer out.
 565          * Now We trim to the true length of the frame.
 566          */
 567         if (pskb_trim_rcsum(skb, len))
 568                 goto out;
 569
 570         if (iph->protocol != IPPROTO_UDP)
 571                 goto out;
 572
 573         len -= iph->ihl*4;
 574         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 575         ulen = ntohs(uh->len);
 576
 577         if (ulen != len)
 578                 goto out;
 579         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 580                 goto out;
 581
 582         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 583                 if (np->local_ip && np->local_ip != iph->daddr)
 584                         continue;
 585                 if (np->remote_ip && np->remote_ip != iph->saddr)
 586                         continue;
 587                 if (np->local_port && np->local_port != ntohs(uh->dest))
 588                         continue;
 589
 590                 np->rx_hook(np, ntohs(uh->source),
 591                                (char *)(uh+1),
 592                                ulen - sizeof(struct udphdr));
 593                 hits++;
 594         }
 595
 596         if (!hits)
 597                 goto out;
 598
 599         kfree_skb(skb);
 600         return 1;
 601
 602 out:
 603         if (atomic_read(&trapped)) {
 604                 kfree_skb(skb);
 605                 return 1;
 606         }
 607
 608         return 0;
 609 }
 610
 611 void netpoll_print_options(struct netpoll *np)
 612 {
 613         printk(KERN_INFO "%s: local port %d\n",
 614                          np->name, np->local_port);
 615         printk(KERN_INFO "%s: local IP %pI4\n",
 616                          np->name, &np->local_ip);
 617         printk(KERN_INFO "%s: interface '%s'\n",
 618                          np->name, np->dev_name);
 619         printk(KERN_INFO "%s: remote port %d\n",
 620                          np->name, np->remote_port);
 621         printk(KERN_INFO "%s: remote IP %pI4\n",
 622                          np->name, &np->remote_ip);
 623         printk(KERN_INFO "%s: remote ethernet address %pM\n",
 624                          np->name, np->remote_mac);
 625 }
 626
 627 int netpoll_parse_options(struct netpoll *np, char *opt)
 628 {
 629         char *cur=opt, *delim;
 630
 631         if (*cur != '@') {
 632                 if ((delim = strchr(cur, '@')) == NULL)
 633                         goto parse_failed;
 634                 *delim = 0;
 635                 np->local_port = simple_strtol(cur, NULL, 10);
 636                 cur = delim;
 637         }
 638         cur++;
 639
 640         if (*cur != '/') {
 641                 if ((delim = strchr(cur, '/')) == NULL)
 642                         goto parse_failed;
 643                 *delim = 0;
 644                 np->local_ip = in_aton(cur);
 645                 cur = delim;
 646         }
 647         cur++;
 648
 649         if (*cur != ',') {
 650                 /* parse out dev name */
 651                 if ((delim = strchr(cur, ',')) == NULL)
 652                         goto parse_failed;
 653                 *delim = 0;
 654                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 655                 cur = delim;
 656         }
 657         cur++;
 658
 659         if (*cur != '@') {
 660                 /* dst port */
 661                 if ((delim = strchr(cur, '@')) == NULL)
 662                         goto parse_failed;
 663                 *delim = 0;
 664                 if (*cur == ' ' || *cur == '\t')
 665                         printk(KERN_INFO "%s: warning: whitespace"
 666                                         "is not allowed\n", np->name);
 667                 np->remote_port = simple_strtol(cur, NULL, 10);
 668                 cur = delim;
 669         }
 670         cur++;
 671
 672         /* dst ip */
 673         if ((delim = strchr(cur, '/')) == NULL)
 674                 goto parse_failed;
 675         *delim = 0;
 676         np->remote_ip = in_aton(cur);
 677         cur = delim + 1;
 678
 679         if (*cur != 0) {
 680                 /* MAC address */
 681                 if ((delim = strchr(cur, ':')) == NULL)
 682                         goto parse_failed;
 683                 *delim = 0;
 684                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 685                 cur = delim + 1;
 686                 if ((delim = strchr(cur, ':')) == NULL)
 687                         goto parse_failed;
 688                 *delim = 0;
 689                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 690                 cur = delim + 1;
 691                 if ((delim = strchr(cur, ':')) == NULL)
 692                         goto parse_failed;
 693                 *delim = 0;
 694                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 695                 cur = delim + 1;
 696                 if ((delim = strchr(cur, ':')) == NULL)
 697                         goto parse_failed;
 698                 *delim = 0;
 699                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 700                 cur = delim + 1;
 701                 if ((delim = strchr(cur, ':')) == NULL)
 702                         goto parse_failed;
 703                 *delim = 0;
 704                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 705                 cur = delim + 1;
 706                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 707         }
 708
 709         netpoll_print_options(np);
 710
 711         return 0;
 712
 713  parse_failed:
 714         printk(KERN_INFO "%s: couldn't parse config at '%s'!\n",
 715                np->name, cur);
 716         return -1;
 717 }
 718
 719 int netpoll_setup(struct netpoll *np)
 720 {
 721         struct net_device *ndev = NULL;
 722         struct in_device *in_dev;
 723         struct netpoll_info *npinfo;
 724         struct netpoll *npe, *tmp;
 725         unsigned long flags;
 726         int err;
 727
 728         if (np->dev_name)
 729                 ndev = dev_get_by_name(&init_net, np->dev_name);
 730         if (!ndev) {
 731                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 732                        np->name, np->dev_name);
 733                 return -ENODEV;
 734         }
 735
 736         np->dev = ndev;
 737         if (!ndev->npinfo) {
 738                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 739                 if (!npinfo) {
 740                         err = -ENOMEM;
 741                         goto put;
 742                 }
 743
 744                 npinfo->rx_flags = 0;
 745                 INIT_LIST_HEAD(&npinfo->rx_np);
 746
 747                 spin_lock_init(&npinfo->rx_lock);
 748                 skb_queue_head_init(&npinfo->arp_tx);
 749                 skb_queue_head_init(&npinfo->txq);
 750                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 751
 752                 atomic_set(&npinfo->refcnt, 1);
 753         } else {
 754                 npinfo = ndev->npinfo;
 755                 atomic_inc(&npinfo->refcnt);
 756         }
 757
 758         if (!ndev->netdev_ops->ndo_poll_controller) {
 759                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 760                        np->name, np->dev_name);
 761                 err = -ENOTSUPP;
 762                 goto release;
 763         }
 764
 765         if (!netif_running(ndev)) {
 766                 unsigned long atmost, atleast;
 767
 768                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 769                        np->name, np->dev_name);
 770
 771                 rtnl_lock();
 772                 err = dev_open(ndev);
 773                 rtnl_unlock();
 774
 775                 if (err) {
 776                         printk(KERN_ERR "%s: failed to open %s\n",
 777                                np->name, ndev->name);
 778                         goto release;
 779                 }
 780
 781                 atleast = jiffies + HZ/10;
 782                 atmost = jiffies + carrier_timeout * HZ;
 783                 while (!netif_carrier_ok(ndev)) {
 784                         if (time_after(jiffies, atmost)) {
 785                                 printk(KERN_NOTICE
 786                                        "%s: timeout waiting for carrier\n",
 787                                        np->name);
 788                                 break;
 789                         }
 790                         msleep(1);
 791                 }
 792
 793                 /* If carrier appears to come up instantly, we don't
 794                  * trust it and pause so that we don't pump all our
 795                  * queued console messages into the bitbucket.
 796                  */
 797
 798                 if (time_before(jiffies, atleast)) {
 799                         printk(KERN_NOTICE "%s: carrier detect appears"
 800                                " untrustworthy, waiting 4 seconds\n",
 801                                np->name);
 802                         msleep(4000);
 803                 }
 804         }
 805
 806         if (!np->local_ip) {
 807                 rcu_read_lock();
 808                 in_dev = __in_dev_get_rcu(ndev);
 809
 810                 if (!in_dev || !in_dev->ifa_list) {
 811                         rcu_read_unlock();
 812                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 813                                np->name, np->dev_name);
 814                         err = -EDESTADDRREQ;
 815                         goto release;
 816                 }
 817
 818                 np->local_ip = in_dev->ifa_list->ifa_local;
 819                 rcu_read_unlock();
 820                 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
 821         }
 822
 823         if (np->rx_hook) {
 824                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 825                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 826                 list_add_tail(&np->rx, &npinfo->rx_np);
 827                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 828         }
 829
 830         /* fill up the skb queue */
 831         refill_skbs();
 832
 833         /* last thing to do is link it to the net device structure */
 834         ndev->npinfo = npinfo;
 835
 836         /* avoid racing with NAPI reading npinfo */
 837         synchronize_rcu();
 838
 839         return 0;
 840
 841  release:
 842         if (!ndev->npinfo) {
 843                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 844                 list_for_each_entry_safe(npe, tmp, &npinfo->rx_np, rx) {
 845                         npe->dev = NULL;
 846                 }
 847                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 848
 849                 kfree(npinfo);
 850         }
 851 put:
 852         dev_put(ndev);
 853         return err;
 854 }
 855
 856 static int __init netpoll_init(void)
 857 {
 858         skb_queue_head_init(&skb_pool);
 859         return 0;
 860 }
 861 core_initcall(netpoll_init);
 862
 863 void netpoll_cleanup(struct netpoll *np)
 864 {
 865         struct netpoll_info *npinfo;
 866         unsigned long flags;
 867
 868         if (np->dev) {
 869                 npinfo = np->dev->npinfo;
 870                 if (npinfo) {
 871                         if (!list_empty(&npinfo->rx_np)) {
 872                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 873                                 list_del(&np->rx);
 874                                 if (list_empty(&npinfo->rx_np))
 875                                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 876                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 877                         }
 878
 879                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 880                                 skb_queue_purge(&npinfo->arp_tx);
 881                                 skb_queue_purge(&npinfo->txq);
 882                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 883
 884                                 /* clean after last, unfinished work */
 885                                 __skb_queue_purge(&npinfo->txq);
 886                                 kfree(npinfo);
 887                                 np->dev->npinfo = NULL;
 888                         }
 889                 }
 890
 891                 dev_put(np->dev);
 892         }
 893
 894         np->dev = NULL;
 895 }
 896
 897 int netpoll_trap(void)
 898 {
 899         return atomic_read(&trapped);
 900 }
 901
 902 void netpoll_set_trap(int trap)
 903 {
 904         if (trap)
 905                 atomic_inc(&trapped);
 906         else
 907                 atomic_dec(&trapped);
 908 }
 909
 910 EXPORT_SYMBOL(netpoll_set_trap);
 911 EXPORT_SYMBOL(netpoll_trap);
 912 EXPORT_SYMBOL(netpoll_print_options);
 913 EXPORT_SYMBOL(netpoll_parse_options);
 914 EXPORT_SYMBOL(netpoll_setup);
 915 EXPORT_SYMBOL(netpoll_cleanup);
 916 EXPORT_SYMBOL(netpoll_send_udp);
 917 EXPORT_SYMBOL(netpoll_poll);