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/smp_lock.h>
  13 #include <linux/netdevice.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/string.h>
  16 #include <linux/inetdevice.h>
  17 #include <linux/inet.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/netpoll.h>
  20 #include <linux/sched.h>
  21 #include <linux/rcupdate.h>
  22 #include <net/tcp.h>
  23 #include <net/udp.h>
  24 #include <asm/unaligned.h>
  25
  26 /*
  27  * We maintain a small pool of fully-sized skbs, to make sure the
  28  * message gets out even in extreme OOM situations.
  29  */
  30
  31 #define MAX_SKBS 32
  32 #define MAX_UDP_CHUNK 1460
  33
  34 static spinlock_t skb_list_lock = SPIN_LOCK_UNLOCKED;
  35 static int nr_skbs;
  36 static struct sk_buff *skbs;
  37
  38 static spinlock_t rx_list_lock = SPIN_LOCK_UNLOCKED;
  39 static LIST_HEAD(rx_list);
  40
  41 static atomic_t trapped;
  42 spinlock_t netpoll_poll_lock = SPIN_LOCK_UNLOCKED;
  43
  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
  53 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  54                              unsigned short ulen, u32 saddr, u32 daddr)
  55 {
  56         if (uh->check == 0)
  57                 return 0;
  58
  59         if (skb->ip_summed == CHECKSUM_HW)
  60                 return csum_tcpudp_magic(
  61                         saddr, daddr, ulen, IPPROTO_UDP, skb->csum);
  62
  63         skb->csum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
  64
  65         return csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
  66 }
  67
  68 void netpoll_poll(struct netpoll *np)
  69 {
  70         /*
  71          * In cases where there is bi-directional communications, reading
  72          * only one message at a time can lead to packets being dropped by
  73          * the network adapter, forcing superfluous retries and possibly
  74          * timeouts.  Thus, we set our budget to a more reasonable value.
  75          */
  76         int budget = 16;
  77         unsigned long flags;
  78
  79         if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
  80                 return;
  81
  82         /* Process pending work on NIC */
  83         np->dev->poll_controller(np->dev);
  84
  85         /* If scheduling is stopped, tickle NAPI bits */
  86         spin_lock_irqsave(&netpoll_poll_lock, flags);
  87         if (np->dev->poll &&
  88             test_bit(__LINK_STATE_RX_SCHED, &np->dev->state)) {
  89                 np->dev->netpoll_rx |= NETPOLL_RX_DROP;
  90                 atomic_inc(&trapped);
  91
  92                 np->dev->poll(np->dev, &budget);
  93
  94                 atomic_dec(&trapped);
  95                 np->dev->netpoll_rx &= ~NETPOLL_RX_DROP;
  96         }
  97         spin_unlock_irqrestore(&netpoll_poll_lock, flags);
  98
  99         zap_completion_queue();
 100 }
 101
 102 static void refill_skbs(void)
 103 {
 104         struct sk_buff *skb;
 105         unsigned long flags;
 106
 107         spin_lock_irqsave(&skb_list_lock, flags);
 108         while (nr_skbs < MAX_SKBS) {
 109                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 110                 if (!skb)
 111                         break;
 112
 113                 skb->next = skbs;
 114                 skbs = skb;
 115                 nr_skbs++;
 116         }
 117         spin_unlock_irqrestore(&skb_list_lock, flags);
 118 }
 119
 120 static void zap_completion_queue(void)
 121 {
 122         unsigned long flags;
 123         struct softnet_data *sd = &get_cpu_var(softnet_data);
 124
 125         if (sd->completion_queue) {
 126                 struct sk_buff *clist;
 127
 128                 local_irq_save(flags);
 129                 clist = sd->completion_queue;
 130                 sd->completion_queue = NULL;
 131                 local_irq_restore(flags);
 132
 133                 while (clist != NULL) {
 134                         struct sk_buff *skb = clist;
 135                         clist = clist->next;
 136                         __kfree_skb(skb);
 137                 }
 138         }
 139
 140         put_cpu_var(softnet_data);
 141 }
 142
 143 static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
 144 {
 145         int once = 1, count = 0;
 146         unsigned long flags;
 147         struct sk_buff *skb = NULL;
 148
 149         zap_completion_queue();
 150 repeat:
 151         if (nr_skbs < MAX_SKBS)
 152                 refill_skbs();
 153
 154         skb = alloc_skb(len, GFP_ATOMIC);
 155
 156         if (!skb) {
 157                 spin_lock_irqsave(&skb_list_lock, flags);
 158                 skb = skbs;
 159                 if (skb)
 160                         skbs = skb->next;
 161                 skb->next = NULL;
 162                 nr_skbs--;
 163                 spin_unlock_irqrestore(&skb_list_lock, flags);
 164         }
 165
 166         if(!skb) {
 167                 count++;
 168                 if (once && (count == 1000000)) {
 169                         printk("out of netpoll skbs!\n");
 170                         once = 0;
 171                 }
 172                 netpoll_poll(np);
 173                 goto repeat;
 174         }
 175
 176         atomic_set(&skb->users, 1);
 177         skb_reserve(skb, reserve);
 178         return skb;
 179 }
 180
 181 void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 182 {
 183         int status;
 184
 185 repeat:
 186         if(!np || !np->dev || !netif_running(np->dev)) {
 187                 __kfree_skb(skb);
 188                 return;
 189         }
 190
 191         spin_lock(&np->dev->xmit_lock);
 192         np->dev->xmit_lock_owner = smp_processor_id();
 193
 194         /*
 195          * network drivers do not expect to be called if the queue is
 196          * stopped.
 197          */
 198         if (netif_queue_stopped(np->dev)) {
 199                 np->dev->xmit_lock_owner = -1;
 200                 spin_unlock(&np->dev->xmit_lock);
 201
 202                 netpoll_poll(np);
 203                 goto repeat;
 204         }
 205
 206         status = np->dev->hard_start_xmit(skb, np->dev);
 207         np->dev->xmit_lock_owner = -1;
 208         spin_unlock(&np->dev->xmit_lock);
 209
 210         /* transmit busy */
 211         if(status) {
 212                 netpoll_poll(np);
 213                 goto repeat;
 214         }
 215 }
 216
 217 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 218 {
 219         int total_len, eth_len, ip_len, udp_len;
 220         struct sk_buff *skb;
 221         struct udphdr *udph;
 222         struct iphdr *iph;
 223         struct ethhdr *eth;
 224
 225         udp_len = len + sizeof(*udph);
 226         ip_len = eth_len = udp_len + sizeof(*iph);
 227         total_len = eth_len + ETH_HLEN;
 228
 229         skb = find_skb(np, total_len, total_len - len);
 230         if (!skb)
 231                 return;
 232
 233         memcpy(skb->data, msg, len);
 234         skb->len += len;
 235
 236         udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 237         udph->source = htons(np->local_port);
 238         udph->dest = htons(np->remote_port);
 239         udph->len = htons(udp_len);
 240         udph->check = 0;
 241
 242         iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 243
 244         /* iph->version = 4; iph->ihl = 5; */
 245         put_unaligned(0x45, (unsigned char *)iph);
 246         iph->tos      = 0;
 247         put_unaligned(htons(ip_len), &(iph->tot_len));
 248         iph->id       = 0;
 249         iph->frag_off = 0;
 250         iph->ttl      = 64;
 251         iph->protocol = IPPROTO_UDP;
 252         iph->check    = 0;
 253         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 254         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 255         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 256
 257         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 258
 259         eth->h_proto = htons(ETH_P_IP);
 260         memcpy(eth->h_source, np->local_mac, 6);
 261         memcpy(eth->h_dest, np->remote_mac, 6);
 262
 263         netpoll_send_skb(np, skb);
 264 }
 265
 266 static void arp_reply(struct sk_buff *skb)
 267 {
 268         struct arphdr *arp;
 269         unsigned char *arp_ptr;
 270         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 271         u32 sip, tip;
 272         struct sk_buff *send_skb;
 273         unsigned long flags;
 274         struct list_head *p;
 275         struct netpoll *np = NULL;
 276
 277         spin_lock_irqsave(&rx_list_lock, flags);
 278         list_for_each(p, &rx_list) {
 279                 np = list_entry(p, struct netpoll, rx_list);
 280                 if ( np->dev == skb->dev )
 281                         break;
 282                 np = NULL;
 283         }
 284         spin_unlock_irqrestore(&rx_list_lock, flags);
 285
 286         if (!np) return;
 287
 288         /* No arp on this interface */
 289         if (skb->dev->flags & IFF_NOARP)
 290                 return;
 291
 292         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 293                                  (2 * skb->dev->addr_len) +
 294                                  (2 * sizeof(u32)))))
 295                 return;
 296
 297         skb->h.raw = skb->nh.raw = skb->data;
 298         arp = skb->nh.arph;
 299
 300         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 301              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 302             arp->ar_pro != htons(ETH_P_IP) ||
 303             arp->ar_op != htons(ARPOP_REQUEST))
 304                 return;
 305
 306         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
 307         memcpy(&sip, arp_ptr, 4);
 308         arp_ptr += 4 + skb->dev->addr_len;
 309         memcpy(&tip, arp_ptr, 4);
 310
 311         /* Should we ignore arp? */
 312         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 313                 return;
 314
 315         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 316         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 317                             LL_RESERVED_SPACE(np->dev));
 318
 319         if (!send_skb)
 320                 return;
 321
 322         send_skb->nh.raw = send_skb->data;
 323         arp = (struct arphdr *) skb_put(send_skb, size);
 324         send_skb->dev = skb->dev;
 325         send_skb->protocol = htons(ETH_P_ARP);
 326
 327         /* Fill the device header for the ARP frame */
 328
 329         if (np->dev->hard_header &&
 330             np->dev->hard_header(send_skb, skb->dev, ptype,
 331                                        np->remote_mac, np->local_mac,
 332                                        send_skb->len) < 0) {
 333                 kfree_skb(send_skb);
 334                 return;
 335         }
 336
 337         /*
 338          * Fill out the arp protocol part.
 339          *
 340          * we only support ethernet device type,
 341          * which (according to RFC 1390) should always equal 1 (Ethernet).
 342          */
 343
 344         arp->ar_hrd = htons(np->dev->type);
 345         arp->ar_pro = htons(ETH_P_IP);
 346         arp->ar_hln = np->dev->addr_len;
 347         arp->ar_pln = 4;
 348         arp->ar_op = htons(type);
 349
 350         arp_ptr=(unsigned char *)(arp + 1);
 351         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 352         arp_ptr += np->dev->addr_len;
 353         memcpy(arp_ptr, &tip, 4);
 354         arp_ptr += 4;
 355         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
 356         arp_ptr += np->dev->addr_len;
 357         memcpy(arp_ptr, &sip, 4);
 358
 359         netpoll_send_skb(np, send_skb);
 360 }
 361
 362 int netpoll_rx(struct sk_buff *skb)
 363 {
 364         int proto, len, ulen;
 365         struct iphdr *iph;
 366         struct udphdr *uh;
 367         struct netpoll *np;
 368         struct list_head *p;
 369         unsigned long flags;
 370
 371         if (skb->dev->type != ARPHRD_ETHER)
 372                 goto out;
 373
 374         /* check if netpoll clients need ARP */
 375         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 376             atomic_read(&trapped)) {
 377                 arp_reply(skb);
 378                 return 1;
 379         }
 380
 381         proto = ntohs(eth_hdr(skb)->h_proto);
 382         if (proto != ETH_P_IP)
 383                 goto out;
 384         if (skb->pkt_type == PACKET_OTHERHOST)
 385                 goto out;
 386         if (skb_shared(skb))
 387                 goto out;
 388
 389         iph = (struct iphdr *)skb->data;
 390         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 391                 goto out;
 392         if (iph->ihl < 5 || iph->version != 4)
 393                 goto out;
 394         if (!pskb_may_pull(skb, iph->ihl*4))
 395                 goto out;
 396         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 397                 goto out;
 398
 399         len = ntohs(iph->tot_len);
 400         if (skb->len < len || len < iph->ihl*4)
 401                 goto out;
 402
 403         if (iph->protocol != IPPROTO_UDP)
 404                 goto out;
 405
 406         len -= iph->ihl*4;
 407         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 408         ulen = ntohs(uh->len);
 409
 410         if (ulen != len)
 411                 goto out;
 412         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr) < 0)
 413                 goto out;
 414
 415         spin_lock_irqsave(&rx_list_lock, flags);
 416         list_for_each(p, &rx_list) {
 417                 np = list_entry(p, struct netpoll, rx_list);
 418                 if (np->dev && np->dev != skb->dev)
 419                         continue;
 420                 if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 421                         continue;
 422                 if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 423                         continue;
 424                 if (np->local_port && np->local_port != ntohs(uh->dest))
 425                         continue;
 426
 427                 spin_unlock_irqrestore(&rx_list_lock, flags);
 428
 429                 if (np->rx_hook)
 430                         np->rx_hook(np, ntohs(uh->source),
 431                                     (char *)(uh+1),
 432                                     ulen - sizeof(struct udphdr));
 433
 434                 return 1;
 435         }
 436         spin_unlock_irqrestore(&rx_list_lock, flags);
 437
 438 out:
 439         return atomic_read(&trapped);
 440 }
 441
 442 int netpoll_parse_options(struct netpoll *np, char *opt)
 443 {
 444         char *cur=opt, *delim;
 445
 446         if(*cur != '@') {
 447                 if ((delim = strchr(cur, '@')) == NULL)
 448                         goto parse_failed;
 449                 *delim=0;
 450                 np->local_port=simple_strtol(cur, NULL, 10);
 451                 cur=delim;
 452         }
 453         cur++;
 454         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 455
 456         if(*cur != '/') {
 457                 if ((delim = strchr(cur, '/')) == NULL)
 458                         goto parse_failed;
 459                 *delim=0;
 460                 np->local_ip=ntohl(in_aton(cur));
 461                 cur=delim;
 462
 463                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 464                        np->name, HIPQUAD(np->local_ip));
 465         }
 466         cur++;
 467
 468         if ( *cur != ',') {
 469                 /* parse out dev name */
 470                 if ((delim = strchr(cur, ',')) == NULL)
 471                         goto parse_failed;
 472                 *delim=0;
 473                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 474                 cur=delim;
 475         }
 476         cur++;
 477
 478         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 479
 480         if ( *cur != '@' ) {
 481                 /* dst port */
 482                 if ((delim = strchr(cur, '@')) == NULL)
 483                         goto parse_failed;
 484                 *delim=0;
 485                 np->remote_port=simple_strtol(cur, NULL, 10);
 486                 cur=delim;
 487         }
 488         cur++;
 489         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 490
 491         /* dst ip */
 492         if ((delim = strchr(cur, '/')) == NULL)
 493                 goto parse_failed;
 494         *delim=0;
 495         np->remote_ip=ntohl(in_aton(cur));
 496         cur=delim+1;
 497
 498         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 499                        np->name, HIPQUAD(np->remote_ip));
 500
 501         if( *cur != 0 )
 502         {
 503                 /* MAC address */
 504                 if ((delim = strchr(cur, ':')) == NULL)
 505                         goto parse_failed;
 506                 *delim=0;
 507                 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
 508                 cur=delim+1;
 509                 if ((delim = strchr(cur, ':')) == NULL)
 510                         goto parse_failed;
 511                 *delim=0;
 512                 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
 513                 cur=delim+1;
 514                 if ((delim = strchr(cur, ':')) == NULL)
 515                         goto parse_failed;
 516                 *delim=0;
 517                 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
 518                 cur=delim+1;
 519                 if ((delim = strchr(cur, ':')) == NULL)
 520                         goto parse_failed;
 521                 *delim=0;
 522                 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
 523                 cur=delim+1;
 524                 if ((delim = strchr(cur, ':')) == NULL)
 525                         goto parse_failed;
 526                 *delim=0;
 527                 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
 528                 cur=delim+1;
 529                 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
 530         }
 531
 532         printk(KERN_INFO "%s: remote ethernet address "
 533                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 534                np->name,
 535                np->remote_mac[0],
 536                np->remote_mac[1],
 537                np->remote_mac[2],
 538                np->remote_mac[3],
 539                np->remote_mac[4],
 540                np->remote_mac[5]);
 541
 542         return 0;
 543
 544  parse_failed:
 545         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 546                np->name, cur);
 547         return -1;
 548 }
 549
 550 int netpoll_setup(struct netpoll *np)
 551 {
 552         struct net_device *ndev = NULL;
 553         struct in_device *in_dev;
 554
 555         if (np->dev_name)
 556                 ndev = dev_get_by_name(np->dev_name);
 557         if (!ndev) {
 558                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 559                        np->name, np->dev_name);
 560                 return -1;
 561         }
 562         if (!ndev->poll_controller) {
 563                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 564                        np->name, np->dev_name);
 565                 goto release;
 566         }
 567
 568         if (!(ndev->flags & IFF_UP)) {
 569                 unsigned short oflags;
 570                 unsigned long atmost, atleast;
 571
 572                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 573                        np->name, np->dev_name);
 574
 575                 oflags = ndev->flags;
 576
 577                 rtnl_shlock();
 578                 if (dev_change_flags(ndev, oflags | IFF_UP) < 0) {
 579                         printk(KERN_ERR "%s: failed to open %s\n",
 580                                np->name, np->dev_name);
 581                         rtnl_shunlock();
 582                         goto release;
 583                 }
 584                 rtnl_shunlock();
 585
 586                 atleast = jiffies + HZ/10;
 587                 atmost = jiffies + 10*HZ;
 588                 while (!netif_carrier_ok(ndev)) {
 589                         if (time_after(jiffies, atmost)) {
 590                                 printk(KERN_NOTICE
 591                                        "%s: timeout waiting for carrier\n",
 592                                        np->name);
 593                                 break;
 594                         }
 595                         cond_resched();
 596                 }
 597
 598                 if (time_before(jiffies, atleast)) {
 599                         printk(KERN_NOTICE "%s: carrier detect appears flaky,"
 600                                " waiting 10 seconds\n",
 601                                np->name);
 602                         while (time_before(jiffies, atmost))
 603                                 cond_resched();
 604                 }
 605         }
 606
 607         if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
 608                 memcpy(np->local_mac, ndev->dev_addr, 6);
 609
 610         if (!np->local_ip) {
 611                 rcu_read_lock();
 612                 in_dev = __in_dev_get(ndev);
 613
 614                 if (!in_dev) {
 615                         rcu_read_unlock();
 616                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 617                                np->name, np->dev_name);
 618                         goto release;
 619                 }
 620
 621                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 622                 rcu_read_unlock();
 623                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 624                        np->name, HIPQUAD(np->local_ip));
 625         }
 626
 627         np->dev = ndev;
 628
 629         if(np->rx_hook) {
 630                 unsigned long flags;
 631
 632                 np->dev->netpoll_rx = NETPOLL_RX_ENABLED;
 633
 634                 spin_lock_irqsave(&rx_list_lock, flags);
 635                 list_add(&np->rx_list, &rx_list);
 636                 spin_unlock_irqrestore(&rx_list_lock, flags);
 637         }
 638
 639         return 0;
 640  release:
 641         dev_put(ndev);
 642         return -1;
 643 }
 644
 645 void netpoll_cleanup(struct netpoll *np)
 646 {
 647         if (np->rx_hook) {
 648                 unsigned long flags;
 649
 650                 spin_lock_irqsave(&rx_list_lock, flags);
 651                 list_del(&np->rx_list);
 652                 spin_unlock_irqrestore(&rx_list_lock, flags);
 653         }
 654
 655         if (np->dev)
 656                 np->dev->netpoll_rx = 0;
 657         dev_put(np->dev);
 658         np->dev = NULL;
 659 }
 660
 661 int netpoll_trap(void)
 662 {
 663         return atomic_read(&trapped);
 664 }
 665
 666 void netpoll_set_trap(int trap)
 667 {
 668         if (trap)
 669                 atomic_inc(&trapped);
 670         else
 671                 atomic_dec(&trapped);
 672 }
 673
 674 EXPORT_SYMBOL(netpoll_set_trap);
 675 EXPORT_SYMBOL(netpoll_trap);
 676 EXPORT_SYMBOL(netpoll_parse_options);
 677 EXPORT_SYMBOL(netpoll_setup);
 678 EXPORT_SYMBOL(netpoll_cleanup);
 679 EXPORT_SYMBOL(netpoll_send_skb);
 680 EXPORT_SYMBOL(netpoll_send_udp);
 681 EXPORT_SYMBOL(netpoll_poll);