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 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
  39
  40 static struct sk_buff_head skb_pool;
  41
  42 static atomic_t trapped;
  43
  44 #define USEC_PER_POLL   50
  45 #define NETPOLL_RX_ENABLED  1
  46 #define NETPOLL_RX_DROP     2
  47
  48 #define MAX_SKB_SIZE \
  49                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  50                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  51
  52 static void zap_completion_queue(void);
  53 static void arp_reply(struct sk_buff *skb);
  54
  55 static unsigned int carrier_timeout = 4;
  56 module_param(carrier_timeout, uint, 0644);
  57
  58 static void queue_process(struct work_struct *work)
  59 {
  60         struct netpoll_info *npinfo =
  61                 container_of(work, struct netpoll_info, tx_work.work);
  62         struct sk_buff *skb;
  63         unsigned long flags;
  64
  65         while ((skb = skb_dequeue(&npinfo->txq))) {
  66                 struct net_device *dev = skb->dev;
  67                 const struct net_device_ops *ops = dev->netdev_ops;
  68                 struct netdev_queue *txq;
  69
  70                 if (!netif_device_present(dev) || !netif_running(dev)) {
  71                         __kfree_skb(skb);
  72                         continue;
  73                 }
  74
  75                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  76
  77                 local_irq_save(flags);
  78                 __netif_tx_lock(txq, smp_processor_id());
  79                 if (netif_tx_queue_stopped(txq) ||
  80                     netif_tx_queue_frozen(txq) ||
  81                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  82                         skb_queue_head(&npinfo->txq, skb);
  83                         __netif_tx_unlock(txq);
  84                         local_irq_restore(flags);
  85
  86                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  87                         return;
  88                 }
  89                 __netif_tx_unlock(txq);
  90                 local_irq_restore(flags);
  91         }
  92 }
  93
  94 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  95                             unsigned short ulen, __be32 saddr, __be32 daddr)
  96 {
  97         __wsum psum;
  98
  99         if (uh->check == 0 || skb_csum_unnecessary(skb))
 100                 return 0;
 101
 102         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 103
 104         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 105             !csum_fold(csum_add(psum, skb->csum)))
 106                 return 0;
 107
 108         skb->csum = psum;
 109
 110         return __skb_checksum_complete(skb);
 111 }
 112
 113 /*
 114  * Check whether delayed processing was scheduled for our NIC. If so,
 115  * we attempt to grab the poll lock and use ->poll() to pump the card.
 116  * If this fails, either we've recursed in ->poll() or it's already
 117  * running on another CPU.
 118  *
 119  * Note: we don't mask interrupts with this lock because we're using
 120  * trylock here and interrupts are already disabled in the softirq
 121  * case. Further, we test the poll_owner to avoid recursion on UP
 122  * systems where the lock doesn't exist.
 123  *
 124  * In cases where there is bi-directional communications, reading only
 125  * one message at a time can lead to packets being dropped by the
 126  * network adapter, forcing superfluous retries and possibly timeouts.
 127  * Thus, we set our budget to greater than 1.
 128  */
 129 static int poll_one_napi(struct netpoll_info *npinfo,
 130                          struct napi_struct *napi, int budget)
 131 {
 132         int work;
 133
 134         /* net_rx_action's ->poll() invocations and our's are
 135          * synchronized by this test which is only made while
 136          * holding the napi->poll_lock.
 137          */
 138         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 139                 return budget;
 140
 141         npinfo->rx_flags |= NETPOLL_RX_DROP;
 142         atomic_inc(&trapped);
 143         set_bit(NAPI_STATE_NPSVC, &napi->state);
 144
 145         work = napi->poll(napi, budget);
 146         trace_napi_poll(napi);
 147
 148         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 149         atomic_dec(&trapped);
 150         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 151
 152         return budget - work;
 153 }
 154
 155 static void poll_napi(struct net_device *dev)
 156 {
 157         struct napi_struct *napi;
 158         int budget = 16;
 159
 160         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 161                 if (napi->poll_owner != smp_processor_id() &&
 162                     spin_trylock(&napi->poll_lock)) {
 163                         budget = poll_one_napi(dev->npinfo, napi, budget);
 164                         spin_unlock(&napi->poll_lock);
 165
 166                         if (!budget)
 167                                 break;
 168                 }
 169         }
 170 }
 171
 172 static void service_arp_queue(struct netpoll_info *npi)
 173 {
 174         if (npi) {
 175                 struct sk_buff *skb;
 176
 177                 while ((skb = skb_dequeue(&npi->arp_tx)))
 178                         arp_reply(skb);
 179         }
 180 }
 181
 182 void netpoll_poll(struct netpoll *np)
 183 {
 184         struct net_device *dev = np->dev;
 185         const struct net_device_ops *ops;
 186
 187         if (!dev || !netif_running(dev))
 188                 return;
 189
 190         ops = dev->netdev_ops;
 191         if (!ops->ndo_poll_controller)
 192                 return;
 193
 194         /* Process pending work on NIC */
 195         ops->ndo_poll_controller(dev);
 196
 197         poll_napi(dev);
 198
 199         service_arp_queue(dev->npinfo);
 200
 201         zap_completion_queue();
 202 }
 203
 204 static void refill_skbs(void)
 205 {
 206         struct sk_buff *skb;
 207         unsigned long flags;
 208
 209         spin_lock_irqsave(&skb_pool.lock, flags);
 210         while (skb_pool.qlen < MAX_SKBS) {
 211                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 212                 if (!skb)
 213                         break;
 214
 215                 __skb_queue_tail(&skb_pool, skb);
 216         }
 217         spin_unlock_irqrestore(&skb_pool.lock, flags);
 218 }
 219
 220 static void zap_completion_queue(void)
 221 {
 222         unsigned long flags;
 223         struct softnet_data *sd = &get_cpu_var(softnet_data);
 224
 225         if (sd->completion_queue) {
 226                 struct sk_buff *clist;
 227
 228                 local_irq_save(flags);
 229                 clist = sd->completion_queue;
 230                 sd->completion_queue = NULL;
 231                 local_irq_restore(flags);
 232
 233                 while (clist != NULL) {
 234                         struct sk_buff *skb = clist;
 235                         clist = clist->next;
 236                         if (skb->destructor) {
 237                                 atomic_inc(&skb->users);
 238                                 dev_kfree_skb_any(skb); /* put this one back */
 239                         } else {
 240                                 __kfree_skb(skb);
 241                         }
 242                 }
 243         }
 244
 245         put_cpu_var(softnet_data);
 246 }
 247
 248 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 249 {
 250         int count = 0;
 251         struct sk_buff *skb;
 252
 253         zap_completion_queue();
 254         refill_skbs();
 255 repeat:
 256
 257         skb = alloc_skb(len, GFP_ATOMIC);
 258         if (!skb)
 259                 skb = skb_dequeue(&skb_pool);
 260
 261         if (!skb) {
 262                 if (++count < 10) {
 263                         netpoll_poll(np);
 264                         goto repeat;
 265                 }
 266                 return NULL;
 267         }
 268
 269         atomic_set(&skb->users, 1);
 270         skb_reserve(skb, reserve);
 271         return skb;
 272 }
 273
 274 static int netpoll_owner_active(struct net_device *dev)
 275 {
 276         struct napi_struct *napi;
 277
 278         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 279                 if (napi->poll_owner == smp_processor_id())
 280                         return 1;
 281         }
 282         return 0;
 283 }
 284
 285 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 286 {
 287         int status = NETDEV_TX_BUSY;
 288         unsigned long tries;
 289         struct net_device *dev = np->dev;
 290         const struct net_device_ops *ops = dev->netdev_ops;
 291         struct netpoll_info *npinfo = np->dev->npinfo;
 292
 293         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 294                 __kfree_skb(skb);
 295                 return;
 296         }
 297
 298         /* don't get messages out of order, and no recursion */
 299         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 300                 struct netdev_queue *txq;
 301                 unsigned long flags;
 302
 303                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 304
 305                 local_irq_save(flags);
 306                 /* try until next clock tick */
 307                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 308                      tries > 0; --tries) {
 309                         if (__netif_tx_trylock(txq)) {
 310                                 if (!netif_tx_queue_stopped(txq)) {
 311                                         status = ops->ndo_start_xmit(skb, dev);
 312                                         if (status == NETDEV_TX_OK)
 313                                                 txq_trans_update(txq);
 314                                 }
 315                                 __netif_tx_unlock(txq);
 316
 317                                 if (status == NETDEV_TX_OK)
 318                                         break;
 319
 320                         }
 321
 322                         /* tickle device maybe there is some cleanup */
 323                         netpoll_poll(np);
 324
 325                         udelay(USEC_PER_POLL);
 326                 }
 327
 328                 WARN_ONCE(!irqs_disabled(),
 329                         "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
 330                         dev->name, ops->ndo_start_xmit);
 331
 332                 local_irq_restore(flags);
 333         }
 334
 335         if (status != NETDEV_TX_OK) {
 336                 skb_queue_tail(&npinfo->txq, skb);
 337                 schedule_delayed_work(&npinfo->tx_work,0);
 338         }
 339 }
 340
 341 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 342 {
 343         int total_len, eth_len, ip_len, udp_len;
 344         struct sk_buff *skb;
 345         struct udphdr *udph;
 346         struct iphdr *iph;
 347         struct ethhdr *eth;
 348
 349         udp_len = len + sizeof(*udph);
 350         ip_len = eth_len = udp_len + sizeof(*iph);
 351         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 352
 353         skb = find_skb(np, total_len, total_len - len);
 354         if (!skb)
 355                 return;
 356
 357         skb_copy_to_linear_data(skb, msg, len);
 358         skb->len += len;
 359
 360         skb_push(skb, sizeof(*udph));
 361         skb_reset_transport_header(skb);
 362         udph = udp_hdr(skb);
 363         udph->source = htons(np->local_port);
 364         udph->dest = htons(np->remote_port);
 365         udph->len = htons(udp_len);
 366         udph->check = 0;
 367         udph->check = csum_tcpudp_magic(np->local_ip,
 368                                         np->remote_ip,
 369                                         udp_len, IPPROTO_UDP,
 370                                         csum_partial(udph, udp_len, 0));
 371         if (udph->check == 0)
 372                 udph->check = CSUM_MANGLED_0;
 373
 374         skb_push(skb, sizeof(*iph));
 375         skb_reset_network_header(skb);
 376         iph = ip_hdr(skb);
 377
 378         /* iph->version = 4; iph->ihl = 5; */
 379         put_unaligned(0x45, (unsigned char *)iph);
 380         iph->tos      = 0;
 381         put_unaligned(htons(ip_len), &(iph->tot_len));
 382         iph->id       = 0;
 383         iph->frag_off = 0;
 384         iph->ttl      = 64;
 385         iph->protocol = IPPROTO_UDP;
 386         iph->check    = 0;
 387         put_unaligned(np->local_ip, &(iph->saddr));
 388         put_unaligned(np->remote_ip, &(iph->daddr));
 389         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 390
 391         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 392         skb_reset_mac_header(skb);
 393         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 394         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 395         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 396
 397         skb->dev = np->dev;
 398
 399         netpoll_send_skb(np, skb);
 400 }
 401
 402 static void arp_reply(struct sk_buff *skb)
 403 {
 404         struct netpoll_info *npinfo = skb->dev->npinfo;
 405         struct arphdr *arp;
 406         unsigned char *arp_ptr;
 407         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 408         __be32 sip, tip;
 409         unsigned char *sha;
 410         struct sk_buff *send_skb;
 411         struct netpoll *np, *tmp;
 412         unsigned long flags;
 413         int hits = 0;
 414
 415         if (list_empty(&npinfo->rx_np))
 416                 return;
 417
 418         /* Before checking the packet, we do some early
 419            inspection whether this is interesting at all */
 420         spin_lock_irqsave(&npinfo->rx_lock, flags);
 421         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 422                 if (np->dev == skb->dev)
 423                         hits++;
 424         }
 425         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 426
 427         /* No netpoll struct is using this dev */
 428         if (!hits)
 429                 return;
 430
 431         /* No arp on this interface */
 432         if (skb->dev->flags & IFF_NOARP)
 433                 return;
 434
 435         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 436                 return;
 437
 438         skb_reset_network_header(skb);
 439         skb_reset_transport_header(skb);
 440         arp = arp_hdr(skb);
 441
 442         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 443              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 444             arp->ar_pro != htons(ETH_P_IP) ||
 445             arp->ar_op != htons(ARPOP_REQUEST))
 446                 return;
 447
 448         arp_ptr = (unsigned char *)(arp+1);
 449         /* save the location of the src hw addr */
 450         sha = arp_ptr;
 451         arp_ptr += skb->dev->addr_len;
 452         memcpy(&sip, arp_ptr, 4);
 453         arp_ptr += 4;
 454         /* If we actually cared about dst hw addr,
 455            it would get copied here */
 456         arp_ptr += skb->dev->addr_len;
 457         memcpy(&tip, arp_ptr, 4);
 458
 459         /* Should we ignore arp? */
 460         if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 461                 return;
 462
 463         size = arp_hdr_len(skb->dev);
 464
 465         spin_lock_irqsave(&npinfo->rx_lock, flags);
 466         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 467                 if (tip != np->local_ip)
 468                         continue;
 469
 470                 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 471                                     LL_RESERVED_SPACE(np->dev));
 472                 if (!send_skb)
 473                         continue;
 474
 475                 skb_reset_network_header(send_skb);
 476                 arp = (struct arphdr *) skb_put(send_skb, size);
 477                 send_skb->dev = skb->dev;
 478                 send_skb->protocol = htons(ETH_P_ARP);
 479
 480                 /* Fill the device header for the ARP frame */
 481                 if (dev_hard_header(send_skb, skb->dev, ptype,
 482                                     sha, np->dev->dev_addr,
 483                                     send_skb->len) < 0) {
 484                         kfree_skb(send_skb);
 485                         continue;
 486                 }
 487
 488                 /*
 489                  * Fill out the arp protocol part.
 490                  *
 491                  * we only support ethernet device type,
 492                  * which (according to RFC 1390) should
 493                  * always equal 1 (Ethernet).
 494                  */
 495
 496                 arp->ar_hrd = htons(np->dev->type);
 497                 arp->ar_pro = htons(ETH_P_IP);
 498                 arp->ar_hln = np->dev->addr_len;
 499                 arp->ar_pln = 4;
 500                 arp->ar_op = htons(type);
 501
 502                 arp_ptr = (unsigned char *)(arp + 1);
 503                 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 504                 arp_ptr += np->dev->addr_len;
 505                 memcpy(arp_ptr, &tip, 4);
 506                 arp_ptr += 4;
 507                 memcpy(arp_ptr, sha, np->dev->addr_len);
 508                 arp_ptr += np->dev->addr_len;
 509                 memcpy(arp_ptr, &sip, 4);
 510
 511                 netpoll_send_skb(np, send_skb);
 512
 513                 /* If there are several rx_hooks for the same address,
 514                    we're fine by sending a single reply */
 515                 break;
 516         }
 517         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 518 }
 519
 520 int __netpoll_rx(struct sk_buff *skb)
 521 {
 522         int proto, len, ulen;
 523         int hits = 0;
 524         struct iphdr *iph;
 525         struct udphdr *uh;
 526         struct netpoll_info *npinfo = skb->dev->npinfo;
 527         struct netpoll *np, *tmp;
 528
 529         if (list_empty(&npinfo->rx_np))
 530                 goto out;
 531
 532         if (skb->dev->type != ARPHRD_ETHER)
 533                 goto out;
 534
 535         /* check if netpoll clients need ARP */
 536         if (skb->protocol == htons(ETH_P_ARP) &&
 537             atomic_read(&trapped)) {
 538                 skb_queue_tail(&npinfo->arp_tx, skb);
 539                 return 1;
 540         }
 541
 542         proto = ntohs(eth_hdr(skb)->h_proto);
 543         if (proto != ETH_P_IP)
 544                 goto out;
 545         if (skb->pkt_type == PACKET_OTHERHOST)
 546                 goto out;
 547         if (skb_shared(skb))
 548                 goto out;
 549
 550         iph = (struct iphdr *)skb->data;
 551         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 552                 goto out;
 553         if (iph->ihl < 5 || iph->version != 4)
 554                 goto out;
 555         if (!pskb_may_pull(skb, iph->ihl*4))
 556                 goto out;
 557         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 558                 goto out;
 559
 560         len = ntohs(iph->tot_len);
 561         if (skb->len < len || len < iph->ihl*4)
 562                 goto out;
 563
 564         /*
 565          * Our transport medium may have padded the buffer out.
 566          * Now We trim to the true length of the frame.
 567          */
 568         if (pskb_trim_rcsum(skb, len))
 569                 goto out;
 570
 571         if (iph->protocol != IPPROTO_UDP)
 572                 goto out;
 573
 574         len -= iph->ihl*4;
 575         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 576         ulen = ntohs(uh->len);
 577
 578         if (ulen != len)
 579                 goto out;
 580         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 581                 goto out;
 582
 583         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 584                 if (np->local_ip && np->local_ip != iph->daddr)
 585                         continue;
 586                 if (np->remote_ip && np->remote_ip != iph->saddr)
 587                         continue;
 588                 if (np->local_port && np->local_port != ntohs(uh->dest))
 589                         continue;
 590
 591                 np->rx_hook(np, ntohs(uh->source),
 592                                (char *)(uh+1),
 593                                ulen - sizeof(struct udphdr));
 594                 hits++;
 595         }
 596
 597         if (!hits)
 598                 goto out;
 599
 600         kfree_skb(skb);
 601         return 1;
 602
 603 out:
 604         if (atomic_read(&trapped)) {
 605                 kfree_skb(skb);
 606                 return 1;
 607         }
 608
 609         return 0;
 610 }
 611
 612 void netpoll_print_options(struct netpoll *np)
 613 {
 614         printk(KERN_INFO "%s: local port %d\n",
 615                          np->name, np->local_port);
 616         printk(KERN_INFO "%s: local IP %pI4\n",
 617                          np->name, &np->local_ip);
 618         printk(KERN_INFO "%s: interface '%s'\n",
 619                          np->name, np->dev_name);
 620         printk(KERN_INFO "%s: remote port %d\n",
 621                          np->name, np->remote_port);
 622         printk(KERN_INFO "%s: remote IP %pI4\n",
 623                          np->name, &np->remote_ip);
 624         printk(KERN_INFO "%s: remote ethernet address %pM\n",
 625                          np->name, np->remote_mac);
 626 }
 627
 628 int netpoll_parse_options(struct netpoll *np, char *opt)
 629 {
 630         char *cur=opt, *delim;
 631
 632         if (*cur != '@') {
 633                 if ((delim = strchr(cur, '@')) == NULL)
 634                         goto parse_failed;
 635                 *delim = 0;
 636                 np->local_port = simple_strtol(cur, NULL, 10);
 637                 cur = delim;
 638         }
 639         cur++;
 640
 641         if (*cur != '/') {
 642                 if ((delim = strchr(cur, '/')) == NULL)
 643                         goto parse_failed;
 644                 *delim = 0;
 645                 np->local_ip = in_aton(cur);
 646                 cur = delim;
 647         }
 648         cur++;
 649
 650         if (*cur != ',') {
 651                 /* parse out dev name */
 652                 if ((delim = strchr(cur, ',')) == NULL)
 653                         goto parse_failed;
 654                 *delim = 0;
 655                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 656                 cur = delim;
 657         }
 658         cur++;
 659
 660         if (*cur != '@') {
 661                 /* dst port */
 662                 if ((delim = strchr(cur, '@')) == NULL)
 663                         goto parse_failed;
 664                 *delim = 0;
 665                 if (*cur == ' ' || *cur == '\t')
 666                         printk(KERN_INFO "%s: warning: whitespace"
 667                                         "is not allowed\n", np->name);
 668                 np->remote_port = simple_strtol(cur, NULL, 10);
 669                 cur = delim;
 670         }
 671         cur++;
 672
 673         /* dst ip */
 674         if ((delim = strchr(cur, '/')) == NULL)
 675                 goto parse_failed;
 676         *delim = 0;
 677         np->remote_ip = in_aton(cur);
 678         cur = delim + 1;
 679
 680         if (*cur != 0) {
 681                 /* MAC address */
 682                 if ((delim = strchr(cur, ':')) == NULL)
 683                         goto parse_failed;
 684                 *delim = 0;
 685                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 686                 cur = delim + 1;
 687                 if ((delim = strchr(cur, ':')) == NULL)
 688                         goto parse_failed;
 689                 *delim = 0;
 690                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 691                 cur = delim + 1;
 692                 if ((delim = strchr(cur, ':')) == NULL)
 693                         goto parse_failed;
 694                 *delim = 0;
 695                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 696                 cur = delim + 1;
 697                 if ((delim = strchr(cur, ':')) == NULL)
 698                         goto parse_failed;
 699                 *delim = 0;
 700                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 701                 cur = delim + 1;
 702                 if ((delim = strchr(cur, ':')) == NULL)
 703                         goto parse_failed;
 704                 *delim = 0;
 705                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 706                 cur = delim + 1;
 707                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 708         }
 709
 710         netpoll_print_options(np);
 711
 712         return 0;
 713
 714  parse_failed:
 715         printk(KERN_INFO "%s: couldn't parse config at '%s'!\n",
 716                np->name, cur);
 717         return -1;
 718 }
 719
 720 int netpoll_setup(struct netpoll *np)
 721 {
 722         struct net_device *ndev = NULL;
 723         struct in_device *in_dev;
 724         struct netpoll_info *npinfo;
 725         struct netpoll *npe, *tmp;
 726         unsigned long flags;
 727         int err;
 728
 729         if (np->dev_name)
 730                 ndev = dev_get_by_name(&init_net, np->dev_name);
 731         if (!ndev) {
 732                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 733                        np->name, np->dev_name);
 734                 return -ENODEV;
 735         }
 736
 737         np->dev = ndev;
 738         if (!ndev->npinfo) {
 739                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 740                 if (!npinfo) {
 741                         err = -ENOMEM;
 742                         goto put;
 743                 }
 744
 745                 npinfo->rx_flags = 0;
 746                 INIT_LIST_HEAD(&npinfo->rx_np);
 747
 748                 spin_lock_init(&npinfo->rx_lock);
 749                 skb_queue_head_init(&npinfo->arp_tx);
 750                 skb_queue_head_init(&npinfo->txq);
 751                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 752
 753                 atomic_set(&npinfo->refcnt, 1);
 754         } else {
 755                 npinfo = ndev->npinfo;
 756                 atomic_inc(&npinfo->refcnt);
 757         }
 758
 759         if (!ndev->netdev_ops->ndo_poll_controller) {
 760                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 761                        np->name, np->dev_name);
 762                 err = -ENOTSUPP;
 763                 goto release;
 764         }
 765
 766         if (!netif_running(ndev)) {
 767                 unsigned long atmost, atleast;
 768
 769                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 770                        np->name, np->dev_name);
 771
 772                 rtnl_lock();
 773                 err = dev_open(ndev);
 774                 rtnl_unlock();
 775
 776                 if (err) {
 777                         printk(KERN_ERR "%s: failed to open %s\n",
 778                                np->name, ndev->name);
 779                         goto release;
 780                 }
 781
 782                 atleast = jiffies + HZ/10;
 783                 atmost = jiffies + carrier_timeout * HZ;
 784                 while (!netif_carrier_ok(ndev)) {
 785                         if (time_after(jiffies, atmost)) {
 786                                 printk(KERN_NOTICE
 787                                        "%s: timeout waiting for carrier\n",
 788                                        np->name);
 789                                 break;
 790                         }
 791                         msleep(1);
 792                 }
 793
 794                 /* If carrier appears to come up instantly, we don't
 795                  * trust it and pause so that we don't pump all our
 796                  * queued console messages into the bitbucket.
 797                  */
 798
 799                 if (time_before(jiffies, atleast)) {
 800                         printk(KERN_NOTICE "%s: carrier detect appears"
 801                                " untrustworthy, waiting 4 seconds\n",
 802                                np->name);
 803                         msleep(4000);
 804                 }
 805         }
 806
 807         if (!np->local_ip) {
 808                 rcu_read_lock();
 809                 in_dev = __in_dev_get_rcu(ndev);
 810
 811                 if (!in_dev || !in_dev->ifa_list) {
 812                         rcu_read_unlock();
 813                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 814                                np->name, np->dev_name);
 815                         err = -EDESTADDRREQ;
 816                         goto release;
 817                 }
 818
 819                 np->local_ip = in_dev->ifa_list->ifa_local;
 820                 rcu_read_unlock();
 821                 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
 822         }
 823
 824         if (np->rx_hook) {
 825                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 826                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 827                 list_add_tail(&np->rx, &npinfo->rx_np);
 828                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 829         }
 830
 831         /* fill up the skb queue */
 832         refill_skbs();
 833
 834         /* last thing to do is link it to the net device structure */
 835         ndev->npinfo = npinfo;
 836
 837         /* avoid racing with NAPI reading npinfo */
 838         synchronize_rcu();
 839
 840         return 0;
 841
 842  release:
 843         if (!ndev->npinfo) {
 844                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 845                 list_for_each_entry_safe(npe, tmp, &npinfo->rx_np, rx) {
 846                         npe->dev = NULL;
 847                 }
 848                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 849
 850                 kfree(npinfo);
 851         }
 852 put:
 853         dev_put(ndev);
 854         return err;
 855 }
 856
 857 static int __init netpoll_init(void)
 858 {
 859         skb_queue_head_init(&skb_pool);
 860         return 0;
 861 }
 862 core_initcall(netpoll_init);
 863
 864 void netpoll_cleanup(struct netpoll *np)
 865 {
 866         struct netpoll_info *npinfo;
 867         unsigned long flags;
 868
 869         if (np->dev) {
 870                 npinfo = np->dev->npinfo;
 871                 if (npinfo) {
 872                         if (!list_empty(&npinfo->rx_np)) {
 873                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 874                                 list_del(&np->rx);
 875                                 if (list_empty(&npinfo->rx_np))
 876                                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 877                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 878                         }
 879
 880                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 881                                 skb_queue_purge(&npinfo->arp_tx);
 882                                 skb_queue_purge(&npinfo->txq);
 883                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 884
 885                                 /* clean after last, unfinished work */
 886                                 __skb_queue_purge(&npinfo->txq);
 887                                 kfree(npinfo);
 888                                 np->dev->npinfo = NULL;
 889                         }
 890                 }
 891
 892                 dev_put(np->dev);
 893         }
 894
 895         np->dev = NULL;
 896 }
 897
 898 int netpoll_trap(void)
 899 {
 900         return atomic_read(&trapped);
 901 }
 902
 903 void netpoll_set_trap(int trap)
 904 {
 905         if (trap)
 906                 atomic_inc(&trapped);
 907         else
 908                 atomic_dec(&trapped);
 909 }
 910
 911 EXPORT_SYMBOL(netpoll_set_trap);
 912 EXPORT_SYMBOL(netpoll_trap);
 913 EXPORT_SYMBOL(netpoll_print_options);
 914 EXPORT_SYMBOL(netpoll_parse_options);
 915 EXPORT_SYMBOL(netpoll_setup);
 916 EXPORT_SYMBOL(netpoll_cleanup);
 917 EXPORT_SYMBOL(netpoll_send_udp);
 918 EXPORT_SYMBOL(netpoll_poll);