SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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/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
  29 /*
  30  * We maintain a small pool of fully-sized skbs, to make sure the
  31  * message gets out even in extreme OOM situations.
  32  */
  33
  34 #define MAX_UDP_CHUNK 1460
  35 #define MAX_SKBS 32
  36 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
  37
  38 static struct sk_buff_head skb_pool;
  39
  40 static atomic_t trapped;
  41
  42 #define USEC_PER_POLL   50
  43 #define NETPOLL_RX_ENABLED  1
  44 #define NETPOLL_RX_DROP     2
  45
  46 #define MAX_SKB_SIZE \
  47                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  48                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  49
  50 static void zap_completion_queue(void);
  51 static void arp_reply(struct sk_buff *skb);
  52
  53 static void queue_process(void *p)
  54 {
  55         struct netpoll_info *npinfo = p;
  56         struct sk_buff *skb;
  57
  58         while ((skb = skb_dequeue(&npinfo->txq))) {
  59                 struct net_device *dev = skb->dev;
  60
  61                 if (!netif_device_present(dev) || !netif_running(dev)) {
  62                         __kfree_skb(skb);
  63                         continue;
  64                 }
  65
  66                 netif_tx_lock_bh(dev);
  67                 if (netif_queue_stopped(dev) ||
  68                     dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
  69                         skb_queue_head(&npinfo->txq, skb);
  70                         netif_tx_unlock_bh(dev);
  71
  72                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  73                         return;
  74                 }
  75
  76                 netif_tx_unlock_bh(dev);
  77         }
  78 }
  79
  80 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  81                              unsigned short ulen, u32 saddr, u32 daddr)
  82 {
  83         unsigned int psum;
  84
  85         if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY)
  86                 return 0;
  87
  88         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
  89
  90         if (skb->ip_summed == CHECKSUM_COMPLETE &&
  91             !(u16)csum_fold(csum_add(psum, skb->csum)))
  92                 return 0;
  93
  94         skb->csum = psum;
  95
  96         return __skb_checksum_complete(skb);
  97 }
  98
  99 /*
 100  * Check whether delayed processing was scheduled for our NIC. If so,
 101  * we attempt to grab the poll lock and use ->poll() to pump the card.
 102  * If this fails, either we've recursed in ->poll() or it's already
 103  * running on another CPU.
 104  *
 105  * Note: we don't mask interrupts with this lock because we're using
 106  * trylock here and interrupts are already disabled in the softirq
 107  * case. Further, we test the poll_owner to avoid recursion on UP
 108  * systems where the lock doesn't exist.
 109  *
 110  * In cases where there is bi-directional communications, reading only
 111  * one message at a time can lead to packets being dropped by the
 112  * network adapter, forcing superfluous retries and possibly timeouts.
 113  * Thus, we set our budget to greater than 1.
 114  */
 115 static void poll_napi(struct netpoll *np)
 116 {
 117         struct netpoll_info *npinfo = np->dev->npinfo;
 118         int budget = 16;
 119
 120         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
 121             npinfo->poll_owner != smp_processor_id() &&
 122             spin_trylock(&npinfo->poll_lock)) {
 123                 npinfo->rx_flags |= NETPOLL_RX_DROP;
 124                 atomic_inc(&trapped);
 125
 126                 np->dev->poll(np->dev, &budget);
 127
 128                 atomic_dec(&trapped);
 129                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 130                 spin_unlock(&npinfo->poll_lock);
 131         }
 132 }
 133
 134 static void service_arp_queue(struct netpoll_info *npi)
 135 {
 136         struct sk_buff *skb;
 137
 138         if (unlikely(!npi))
 139                 return;
 140
 141         skb = skb_dequeue(&npi->arp_tx);
 142
 143         while (skb != NULL) {
 144                 arp_reply(skb);
 145                 skb = skb_dequeue(&npi->arp_tx);
 146         }
 147         return;
 148 }
 149
 150 void netpoll_poll(struct netpoll *np)
 151 {
 152         if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
 153                 return;
 154
 155         /* Process pending work on NIC */
 156         np->dev->poll_controller(np->dev);
 157         if (np->dev->poll)
 158                 poll_napi(np);
 159
 160         service_arp_queue(np->dev->npinfo);
 161
 162         zap_completion_queue();
 163 }
 164
 165 static void refill_skbs(void)
 166 {
 167         struct sk_buff *skb;
 168         unsigned long flags;
 169
 170         spin_lock_irqsave(&skb_pool.lock, flags);
 171         while (skb_pool.qlen < MAX_SKBS) {
 172                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 173                 if (!skb)
 174                         break;
 175
 176                 __skb_queue_tail(&skb_pool, skb);
 177         }
 178         spin_unlock_irqrestore(&skb_pool.lock, flags);
 179 }
 180
 181 static void zap_completion_queue(void)
 182 {
 183         unsigned long flags;
 184         struct softnet_data *sd = &get_cpu_var(softnet_data);
 185
 186         if (sd->completion_queue) {
 187                 struct sk_buff *clist;
 188
 189                 local_irq_save(flags);
 190                 clist = sd->completion_queue;
 191                 sd->completion_queue = NULL;
 192                 local_irq_restore(flags);
 193
 194                 while (clist != NULL) {
 195                         struct sk_buff *skb = clist;
 196                         clist = clist->next;
 197                         if(skb->destructor)
 198                                 dev_kfree_skb_any(skb); /* put this one back */
 199                         else
 200                                 __kfree_skb(skb);
 201                 }
 202         }
 203
 204         put_cpu_var(softnet_data);
 205 }
 206
 207 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 208 {
 209         int count = 0;
 210         struct sk_buff *skb;
 211
 212         zap_completion_queue();
 213         refill_skbs();
 214 repeat:
 215
 216         skb = alloc_skb(len, GFP_ATOMIC);
 217         if (!skb)
 218                 skb = skb_dequeue(&skb_pool);
 219
 220         if(!skb) {
 221                 if (++count < 10) {
 222                         netpoll_poll(np);
 223                         goto repeat;
 224                 }
 225                 return NULL;
 226         }
 227
 228         atomic_set(&skb->users, 1);
 229         skb_reserve(skb, reserve);
 230         return skb;
 231 }
 232
 233 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 234 {
 235         int status = NETDEV_TX_BUSY;
 236         unsigned long tries;
 237         struct net_device *dev = np->dev;
 238         struct netpoll_info *npinfo = np->dev->npinfo;
 239
 240         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 241                 __kfree_skb(skb);
 242                 return;
 243         }
 244
 245         /* don't get messages out of order, and no recursion */
 246         if ( skb_queue_len(&npinfo->txq) == 0
 247              && npinfo->poll_owner != smp_processor_id()
 248              && netif_tx_trylock(dev)) {
 249
 250                 /* try until next clock tick */
 251                 for(tries = jiffies_to_usecs(1)/USEC_PER_POLL; tries > 0; --tries) {
 252                         if (!netif_queue_stopped(dev))
 253                                 status = dev->hard_start_xmit(skb, dev);
 254
 255                         if (status == NETDEV_TX_OK)
 256                                 break;
 257
 258                         /* tickle device maybe there is some cleanup */
 259                         netpoll_poll(np);
 260
 261                         udelay(USEC_PER_POLL);
 262                 }
 263                 netif_tx_unlock(dev);
 264         }
 265
 266         if (status != NETDEV_TX_OK) {
 267                 skb_queue_tail(&npinfo->txq, skb);
 268                 schedule_work(&npinfo->tx_work);
 269         }
 270 }
 271
 272 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 273 {
 274         int total_len, eth_len, ip_len, udp_len;
 275         struct sk_buff *skb;
 276         struct udphdr *udph;
 277         struct iphdr *iph;
 278         struct ethhdr *eth;
 279
 280         udp_len = len + sizeof(*udph);
 281         ip_len = eth_len = udp_len + sizeof(*iph);
 282         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 283
 284         skb = find_skb(np, total_len, total_len - len);
 285         if (!skb)
 286                 return;
 287
 288         memcpy(skb->data, msg, len);
 289         skb->len += len;
 290
 291         skb->h.uh = udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 292         udph->source = htons(np->local_port);
 293         udph->dest = htons(np->remote_port);
 294         udph->len = htons(udp_len);
 295         udph->check = 0;
 296         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
 297                                         htonl(np->remote_ip),
 298                                         udp_len, IPPROTO_UDP,
 299                                         csum_partial((unsigned char *)udph, udp_len, 0));
 300         if (udph->check == 0)
 301                 udph->check = -1;
 302
 303         skb->nh.iph = iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 304
 305         /* iph->version = 4; iph->ihl = 5; */
 306         put_unaligned(0x45, (unsigned char *)iph);
 307         iph->tos      = 0;
 308         put_unaligned(htons(ip_len), &(iph->tot_len));
 309         iph->id       = 0;
 310         iph->frag_off = 0;
 311         iph->ttl      = 64;
 312         iph->protocol = IPPROTO_UDP;
 313         iph->check    = 0;
 314         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 315         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 316         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 317
 318         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 319         skb->mac.raw = skb->data;
 320         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 321         memcpy(eth->h_source, np->local_mac, 6);
 322         memcpy(eth->h_dest, np->remote_mac, 6);
 323
 324         skb->dev = np->dev;
 325
 326         netpoll_send_skb(np, skb);
 327 }
 328
 329 static void arp_reply(struct sk_buff *skb)
 330 {
 331         struct netpoll_info *npinfo = skb->dev->npinfo;
 332         struct arphdr *arp;
 333         unsigned char *arp_ptr;
 334         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 335         u32 sip, tip;
 336         struct sk_buff *send_skb;
 337         struct netpoll *np = NULL;
 338
 339         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 340                 np = npinfo->rx_np;
 341         if (!np)
 342                 return;
 343
 344         /* No arp on this interface */
 345         if (skb->dev->flags & IFF_NOARP)
 346                 return;
 347
 348         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 349                                  (2 * skb->dev->addr_len) +
 350                                  (2 * sizeof(u32)))))
 351                 return;
 352
 353         skb->h.raw = skb->nh.raw = skb->data;
 354         arp = skb->nh.arph;
 355
 356         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 357              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 358             arp->ar_pro != htons(ETH_P_IP) ||
 359             arp->ar_op != htons(ARPOP_REQUEST))
 360                 return;
 361
 362         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
 363         memcpy(&sip, arp_ptr, 4);
 364         arp_ptr += 4 + skb->dev->addr_len;
 365         memcpy(&tip, arp_ptr, 4);
 366
 367         /* Should we ignore arp? */
 368         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 369                 return;
 370
 371         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 372         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 373                             LL_RESERVED_SPACE(np->dev));
 374
 375         if (!send_skb)
 376                 return;
 377
 378         send_skb->nh.raw = send_skb->data;
 379         arp = (struct arphdr *) skb_put(send_skb, size);
 380         send_skb->dev = skb->dev;
 381         send_skb->protocol = htons(ETH_P_ARP);
 382
 383         /* Fill the device header for the ARP frame */
 384
 385         if (np->dev->hard_header &&
 386             np->dev->hard_header(send_skb, skb->dev, ptype,
 387                                        np->remote_mac, np->local_mac,
 388                                        send_skb->len) < 0) {
 389                 kfree_skb(send_skb);
 390                 return;
 391         }
 392
 393         /*
 394          * Fill out the arp protocol part.
 395          *
 396          * we only support ethernet device type,
 397          * which (according to RFC 1390) should always equal 1 (Ethernet).
 398          */
 399
 400         arp->ar_hrd = htons(np->dev->type);
 401         arp->ar_pro = htons(ETH_P_IP);
 402         arp->ar_hln = np->dev->addr_len;
 403         arp->ar_pln = 4;
 404         arp->ar_op = htons(type);
 405
 406         arp_ptr=(unsigned char *)(arp + 1);
 407         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 408         arp_ptr += np->dev->addr_len;
 409         memcpy(arp_ptr, &tip, 4);
 410         arp_ptr += 4;
 411         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
 412         arp_ptr += np->dev->addr_len;
 413         memcpy(arp_ptr, &sip, 4);
 414
 415         netpoll_send_skb(np, send_skb);
 416 }
 417
 418 int __netpoll_rx(struct sk_buff *skb)
 419 {
 420         int proto, len, ulen;
 421         struct iphdr *iph;
 422         struct udphdr *uh;
 423         struct netpoll_info *npi = skb->dev->npinfo;
 424         struct netpoll *np = npi->rx_np;
 425
 426
 427         if (!np)
 428                 goto out;
 429         if (skb->dev->type != ARPHRD_ETHER)
 430                 goto out;
 431
 432         /* check if netpoll clients need ARP */
 433         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 434             atomic_read(&trapped)) {
 435                 skb_queue_tail(&npi->arp_tx, skb);
 436                 return 1;
 437         }
 438
 439         proto = ntohs(eth_hdr(skb)->h_proto);
 440         if (proto != ETH_P_IP)
 441                 goto out;
 442         if (skb->pkt_type == PACKET_OTHERHOST)
 443                 goto out;
 444         if (skb_shared(skb))
 445                 goto out;
 446
 447         iph = (struct iphdr *)skb->data;
 448         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 449                 goto out;
 450         if (iph->ihl < 5 || iph->version != 4)
 451                 goto out;
 452         if (!pskb_may_pull(skb, iph->ihl*4))
 453                 goto out;
 454         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 455                 goto out;
 456
 457         len = ntohs(iph->tot_len);
 458         if (skb->len < len || len < iph->ihl*4)
 459                 goto out;
 460
 461         if (iph->protocol != IPPROTO_UDP)
 462                 goto out;
 463
 464         len -= iph->ihl*4;
 465         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 466         ulen = ntohs(uh->len);
 467
 468         if (ulen != len)
 469                 goto out;
 470         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 471                 goto out;
 472         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 473                 goto out;
 474         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 475                 goto out;
 476         if (np->local_port && np->local_port != ntohs(uh->dest))
 477                 goto out;
 478
 479         np->rx_hook(np, ntohs(uh->source),
 480                     (char *)(uh+1),
 481                     ulen - sizeof(struct udphdr));
 482
 483         kfree_skb(skb);
 484         return 1;
 485
 486 out:
 487         if (atomic_read(&trapped)) {
 488                 kfree_skb(skb);
 489                 return 1;
 490         }
 491
 492         return 0;
 493 }
 494
 495 int netpoll_parse_options(struct netpoll *np, char *opt)
 496 {
 497         char *cur=opt, *delim;
 498
 499         if(*cur != '@') {
 500                 if ((delim = strchr(cur, '@')) == NULL)
 501                         goto parse_failed;
 502                 *delim=0;
 503                 np->local_port=simple_strtol(cur, NULL, 10);
 504                 cur=delim;
 505         }
 506         cur++;
 507         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 508
 509         if(*cur != '/') {
 510                 if ((delim = strchr(cur, '/')) == NULL)
 511                         goto parse_failed;
 512                 *delim=0;
 513                 np->local_ip=ntohl(in_aton(cur));
 514                 cur=delim;
 515
 516                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 517                        np->name, HIPQUAD(np->local_ip));
 518         }
 519         cur++;
 520
 521         if ( *cur != ',') {
 522                 /* parse out dev name */
 523                 if ((delim = strchr(cur, ',')) == NULL)
 524                         goto parse_failed;
 525                 *delim=0;
 526                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 527                 cur=delim;
 528         }
 529         cur++;
 530
 531         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 532
 533         if ( *cur != '@' ) {
 534                 /* dst port */
 535                 if ((delim = strchr(cur, '@')) == NULL)
 536                         goto parse_failed;
 537                 *delim=0;
 538                 np->remote_port=simple_strtol(cur, NULL, 10);
 539                 cur=delim;
 540         }
 541         cur++;
 542         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 543
 544         /* dst ip */
 545         if ((delim = strchr(cur, '/')) == NULL)
 546                 goto parse_failed;
 547         *delim=0;
 548         np->remote_ip=ntohl(in_aton(cur));
 549         cur=delim+1;
 550
 551         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 552                        np->name, HIPQUAD(np->remote_ip));
 553
 554         if( *cur != 0 )
 555         {
 556                 /* MAC address */
 557                 if ((delim = strchr(cur, ':')) == NULL)
 558                         goto parse_failed;
 559                 *delim=0;
 560                 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
 561                 cur=delim+1;
 562                 if ((delim = strchr(cur, ':')) == NULL)
 563                         goto parse_failed;
 564                 *delim=0;
 565                 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
 566                 cur=delim+1;
 567                 if ((delim = strchr(cur, ':')) == NULL)
 568                         goto parse_failed;
 569                 *delim=0;
 570                 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
 571                 cur=delim+1;
 572                 if ((delim = strchr(cur, ':')) == NULL)
 573                         goto parse_failed;
 574                 *delim=0;
 575                 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
 576                 cur=delim+1;
 577                 if ((delim = strchr(cur, ':')) == NULL)
 578                         goto parse_failed;
 579                 *delim=0;
 580                 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
 581                 cur=delim+1;
 582                 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
 583         }
 584
 585         printk(KERN_INFO "%s: remote ethernet address "
 586                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 587                np->name,
 588                np->remote_mac[0],
 589                np->remote_mac[1],
 590                np->remote_mac[2],
 591                np->remote_mac[3],
 592                np->remote_mac[4],
 593                np->remote_mac[5]);
 594
 595         return 0;
 596
 597  parse_failed:
 598         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 599                np->name, cur);
 600         return -1;
 601 }
 602
 603 int netpoll_setup(struct netpoll *np)
 604 {
 605         struct net_device *ndev = NULL;
 606         struct in_device *in_dev;
 607         struct netpoll_info *npinfo;
 608         unsigned long flags;
 609         int err;
 610
 611         if (np->dev_name)
 612                 ndev = dev_get_by_name(np->dev_name);
 613         if (!ndev) {
 614                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 615                        np->name, np->dev_name);
 616                 return -ENODEV;
 617         }
 618
 619         np->dev = ndev;
 620         if (!ndev->npinfo) {
 621                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 622                 if (!npinfo) {
 623                         err = -ENOMEM;
 624                         goto release;
 625                 }
 626
 627                 npinfo->rx_flags = 0;
 628                 npinfo->rx_np = NULL;
 629                 spin_lock_init(&npinfo->poll_lock);
 630                 npinfo->poll_owner = -1;
 631
 632                 spin_lock_init(&npinfo->rx_lock);
 633                 skb_queue_head_init(&npinfo->arp_tx);
 634                 skb_queue_head_init(&npinfo->txq);
 635                 INIT_WORK(&npinfo->tx_work, queue_process, npinfo);
 636
 637                 atomic_set(&npinfo->refcnt, 1);
 638         } else {
 639                 npinfo = ndev->npinfo;
 640                 atomic_inc(&npinfo->refcnt);
 641         }
 642
 643         if (!ndev->poll_controller) {
 644                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 645                        np->name, np->dev_name);
 646                 err = -ENOTSUPP;
 647                 goto release;
 648         }
 649
 650         if (!netif_running(ndev)) {
 651                 unsigned long atmost, atleast;
 652
 653                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 654                        np->name, np->dev_name);
 655
 656                 rtnl_lock();
 657                 err = dev_open(ndev);
 658                 rtnl_unlock();
 659
 660                 if (err) {
 661                         printk(KERN_ERR "%s: failed to open %s\n",
 662                                np->name, ndev->name);
 663                         goto release;
 664                 }
 665
 666                 atleast = jiffies + HZ/10;
 667                 atmost = jiffies + 4*HZ;
 668                 while (!netif_carrier_ok(ndev)) {
 669                         if (time_after(jiffies, atmost)) {
 670                                 printk(KERN_NOTICE
 671                                        "%s: timeout waiting for carrier\n",
 672                                        np->name);
 673                                 break;
 674                         }
 675                         cond_resched();
 676                 }
 677
 678                 /* If carrier appears to come up instantly, we don't
 679                  * trust it and pause so that we don't pump all our
 680                  * queued console messages into the bitbucket.
 681                  */
 682
 683                 if (time_before(jiffies, atleast)) {
 684                         printk(KERN_NOTICE "%s: carrier detect appears"
 685                                " untrustworthy, waiting 4 seconds\n",
 686                                np->name);
 687                         msleep(4000);
 688                 }
 689         }
 690
 691         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
 692                 memcpy(np->local_mac, ndev->dev_addr, 6);
 693
 694         if (!np->local_ip) {
 695                 rcu_read_lock();
 696                 in_dev = __in_dev_get_rcu(ndev);
 697
 698                 if (!in_dev || !in_dev->ifa_list) {
 699                         rcu_read_unlock();
 700                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 701                                np->name, np->dev_name);
 702                         err = -EDESTADDRREQ;
 703                         goto release;
 704                 }
 705
 706                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 707                 rcu_read_unlock();
 708                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 709                        np->name, HIPQUAD(np->local_ip));
 710         }
 711
 712         if (np->rx_hook) {
 713                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 714                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 715                 npinfo->rx_np = np;
 716                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 717         }
 718
 719         /* fill up the skb queue */
 720         refill_skbs();
 721
 722         /* last thing to do is link it to the net device structure */
 723         ndev->npinfo = npinfo;
 724
 725         /* avoid racing with NAPI reading npinfo */
 726         synchronize_rcu();
 727
 728         return 0;
 729
 730  release:
 731         if (!ndev->npinfo)
 732                 kfree(npinfo);
 733         np->dev = NULL;
 734         dev_put(ndev);
 735         return err;
 736 }
 737
 738 static int __init netpoll_init(void) {
 739         skb_queue_head_init(&skb_pool);
 740         return 0;
 741 }
 742 core_initcall(netpoll_init);
 743
 744 void netpoll_cleanup(struct netpoll *np)
 745 {
 746         struct netpoll_info *npinfo;
 747         unsigned long flags;
 748
 749         if (np->dev) {
 750                 npinfo = np->dev->npinfo;
 751                 if (npinfo) {
 752                         if (npinfo->rx_np == np) {
 753                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 754                                 npinfo->rx_np = NULL;
 755                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 756                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 757                         }
 758
 759                         np->dev->npinfo = NULL;
 760                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 761                                 skb_queue_purge(&npinfo->arp_tx);
 762                                 skb_queue_purge(&npinfo->txq);
 763                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 764                                 flush_scheduled_work();
 765
 766                                 kfree(npinfo);
 767                         }
 768                 }
 769
 770                 dev_put(np->dev);
 771         }
 772
 773         np->dev = NULL;
 774 }
 775
 776 int netpoll_trap(void)
 777 {
 778         return atomic_read(&trapped);
 779 }
 780
 781 void netpoll_set_trap(int trap)
 782 {
 783         if (trap)
 784                 atomic_inc(&trapped);
 785         else
 786                 atomic_dec(&trapped);
 787 }
 788
 789 EXPORT_SYMBOL(netpoll_set_trap);
 790 EXPORT_SYMBOL(netpoll_trap);
 791 EXPORT_SYMBOL(netpoll_parse_options);
 792 EXPORT_SYMBOL(netpoll_setup);
 793 EXPORT_SYMBOL(netpoll_cleanup);
 794 EXPORT_SYMBOL(netpoll_send_udp);
 795 EXPORT_SYMBOL(netpoll_poll);