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/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/delay.h>
  22 #include <linux/rcupdate.h>
  23 #include <linux/workqueue.h>
  24 #include <net/tcp.h>
  25 #include <net/udp.h>
  26 #include <asm/unaligned.h>
  27
  28 /*
  29  * We maintain a small pool of fully-sized skbs, to make sure the
  30  * message gets out even in extreme OOM situations.
  31  */
  32
  33 #define MAX_UDP_CHUNK 1460
  34 #define MAX_SKBS 32
  35 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
  36 #define MAX_RETRIES 20000
  37
  38 static DEFINE_SPINLOCK(skb_list_lock);
  39 static int nr_skbs;
  40 static struct sk_buff *skbs;
  41
  42 static DEFINE_SPINLOCK(queue_lock);
  43 static int queue_depth;
  44 static struct sk_buff *queue_head, *queue_tail;
  45
  46 static atomic_t trapped;
  47
  48 #define NETPOLL_RX_ENABLED  1
  49 #define NETPOLL_RX_DROP     2
  50
  51 #define MAX_SKB_SIZE \
  52                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  53                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  54
  55 static void zap_completion_queue(void);
  56
  57 static void queue_process(void *p)
  58 {
  59         unsigned long flags;
  60         struct sk_buff *skb;
  61
  62         while (queue_head) {
  63                 spin_lock_irqsave(&queue_lock, flags);
  64
  65                 skb = queue_head;
  66                 queue_head = skb->next;
  67                 if (skb == queue_tail)
  68                         queue_head = NULL;
  69
  70                 queue_depth--;
  71
  72                 spin_unlock_irqrestore(&queue_lock, flags);
  73
  74                 dev_queue_xmit(skb);
  75         }
  76 }
  77
  78 static DECLARE_WORK(send_queue, queue_process, NULL);
  79
  80 void netpoll_queue(struct sk_buff *skb)
  81 {
  82         unsigned long flags;
  83
  84         if (queue_depth == MAX_QUEUE_DEPTH) {
  85                 __kfree_skb(skb);
  86                 return;
  87         }
  88
  89         spin_lock_irqsave(&queue_lock, flags);
  90         if (!queue_head)
  91                 queue_head = skb;
  92         else
  93                 queue_tail->next = skb;
  94         queue_tail = skb;
  95         queue_depth++;
  96         spin_unlock_irqrestore(&queue_lock, flags);
  97
  98         schedule_work(&send_queue);
  99 }
 100
 101 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 102                              unsigned short ulen, u32 saddr, u32 daddr)
 103 {
 104         unsigned int psum;
 105
 106         if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY)
 107                 return 0;
 108
 109         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 110
 111         if (skb->ip_summed == CHECKSUM_HW &&
 112             !(u16)csum_fold(csum_add(psum, skb->csum)))
 113                 return 0;
 114
 115         skb->csum = psum;
 116
 117         return __skb_checksum_complete(skb);
 118 }
 119
 120 /*
 121  * Check whether delayed processing was scheduled for our NIC. If so,
 122  * we attempt to grab the poll lock and use ->poll() to pump the card.
 123  * If this fails, either we've recursed in ->poll() or it's already
 124  * running on another CPU.
 125  *
 126  * Note: we don't mask interrupts with this lock because we're using
 127  * trylock here and interrupts are already disabled in the softirq
 128  * case. Further, we test the poll_owner to avoid recursion on UP
 129  * systems where the lock doesn't exist.
 130  *
 131  * In cases where there is bi-directional communications, reading only
 132  * one message at a time can lead to packets being dropped by the
 133  * network adapter, forcing superfluous retries and possibly timeouts.
 134  * Thus, we set our budget to greater than 1.
 135  */
 136 static void poll_napi(struct netpoll *np)
 137 {
 138         struct netpoll_info *npinfo = np->dev->npinfo;
 139         int budget = 16;
 140
 141         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
 142             npinfo->poll_owner != smp_processor_id() &&
 143             spin_trylock(&npinfo->poll_lock)) {
 144                 npinfo->rx_flags |= NETPOLL_RX_DROP;
 145                 atomic_inc(&trapped);
 146
 147                 np->dev->poll(np->dev, &budget);
 148
 149                 atomic_dec(&trapped);
 150                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 151                 spin_unlock(&npinfo->poll_lock);
 152         }
 153 }
 154
 155 void netpoll_poll(struct netpoll *np)
 156 {
 157         if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
 158                 return;
 159
 160         /* Process pending work on NIC */
 161         np->dev->poll_controller(np->dev);
 162         if (np->dev->poll)
 163                 poll_napi(np);
 164
 165         zap_completion_queue();
 166 }
 167
 168 static void refill_skbs(void)
 169 {
 170         struct sk_buff *skb;
 171         unsigned long flags;
 172
 173         spin_lock_irqsave(&skb_list_lock, flags);
 174         while (nr_skbs < MAX_SKBS) {
 175                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 176                 if (!skb)
 177                         break;
 178
 179                 skb->next = skbs;
 180                 skbs = skb;
 181                 nr_skbs++;
 182         }
 183         spin_unlock_irqrestore(&skb_list_lock, flags);
 184 }
 185
 186 static void zap_completion_queue(void)
 187 {
 188         unsigned long flags;
 189         struct softnet_data *sd = &get_cpu_var(softnet_data);
 190
 191         if (sd->completion_queue) {
 192                 struct sk_buff *clist;
 193
 194                 local_irq_save(flags);
 195                 clist = sd->completion_queue;
 196                 sd->completion_queue = NULL;
 197                 local_irq_restore(flags);
 198
 199                 while (clist != NULL) {
 200                         struct sk_buff *skb = clist;
 201                         clist = clist->next;
 202                         if(skb->destructor)
 203                                 dev_kfree_skb_any(skb); /* put this one back */
 204                         else
 205                                 __kfree_skb(skb);
 206                 }
 207         }
 208
 209         put_cpu_var(softnet_data);
 210 }
 211
 212 static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
 213 {
 214         int once = 1, count = 0;
 215         unsigned long flags;
 216         struct sk_buff *skb = NULL;
 217
 218         zap_completion_queue();
 219 repeat:
 220         if (nr_skbs < MAX_SKBS)
 221                 refill_skbs();
 222
 223         skb = alloc_skb(len, GFP_ATOMIC);
 224
 225         if (!skb) {
 226                 spin_lock_irqsave(&skb_list_lock, flags);
 227                 skb = skbs;
 228                 if (skb) {
 229                         skbs = skb->next;
 230                         skb->next = NULL;
 231                         nr_skbs--;
 232                 }
 233                 spin_unlock_irqrestore(&skb_list_lock, flags);
 234         }
 235
 236         if(!skb) {
 237                 count++;
 238                 if (once && (count == 1000000)) {
 239                         printk("out of netpoll skbs!\n");
 240                         once = 0;
 241                 }
 242                 netpoll_poll(np);
 243                 goto repeat;
 244         }
 245
 246         atomic_set(&skb->users, 1);
 247         skb_reserve(skb, reserve);
 248         return skb;
 249 }
 250
 251 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 252 {
 253         int status;
 254         struct netpoll_info *npinfo;
 255
 256         if (!np || !np->dev || !netif_running(np->dev)) {
 257                 __kfree_skb(skb);
 258                 return;
 259         }
 260
 261         npinfo = np->dev->npinfo;
 262
 263         /* avoid recursion */
 264         if (npinfo->poll_owner == smp_processor_id() ||
 265             np->dev->xmit_lock_owner == smp_processor_id()) {
 266                 if (np->drop)
 267                         np->drop(skb);
 268                 else
 269                         __kfree_skb(skb);
 270                 return;
 271         }
 272
 273         do {
 274                 npinfo->tries--;
 275                 spin_lock(&np->dev->xmit_lock);
 276                 np->dev->xmit_lock_owner = smp_processor_id();
 277
 278                 /*
 279                  * network drivers do not expect to be called if the queue is
 280                  * stopped.
 281                  */
 282                 if (netif_queue_stopped(np->dev)) {
 283                         np->dev->xmit_lock_owner = -1;
 284                         spin_unlock(&np->dev->xmit_lock);
 285                         netpoll_poll(np);
 286                         udelay(50);
 287                         continue;
 288                 }
 289
 290                 status = np->dev->hard_start_xmit(skb, np->dev);
 291                 np->dev->xmit_lock_owner = -1;
 292                 spin_unlock(&np->dev->xmit_lock);
 293
 294                 /* success */
 295                 if(!status) {
 296                         npinfo->tries = MAX_RETRIES; /* reset */
 297                         return;
 298                 }
 299
 300                 /* transmit busy */
 301                 netpoll_poll(np);
 302                 udelay(50);
 303         } while (npinfo->tries > 0);
 304 }
 305
 306 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 307 {
 308         int total_len, eth_len, ip_len, udp_len;
 309         struct sk_buff *skb;
 310         struct udphdr *udph;
 311         struct iphdr *iph;
 312         struct ethhdr *eth;
 313
 314         udp_len = len + sizeof(*udph);
 315         ip_len = eth_len = udp_len + sizeof(*iph);
 316         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 317
 318         skb = find_skb(np, total_len, total_len - len);
 319         if (!skb)
 320                 return;
 321
 322         memcpy(skb->data, msg, len);
 323         skb->len += len;
 324
 325         udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 326         udph->source = htons(np->local_port);
 327         udph->dest = htons(np->remote_port);
 328         udph->len = htons(udp_len);
 329         udph->check = 0;
 330
 331         iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 332
 333         /* iph->version = 4; iph->ihl = 5; */
 334         put_unaligned(0x45, (unsigned char *)iph);
 335         iph->tos      = 0;
 336         put_unaligned(htons(ip_len), &(iph->tot_len));
 337         iph->id       = 0;
 338         iph->frag_off = 0;
 339         iph->ttl      = 64;
 340         iph->protocol = IPPROTO_UDP;
 341         iph->check    = 0;
 342         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 343         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 344         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 345
 346         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 347
 348         eth->h_proto = htons(ETH_P_IP);
 349         memcpy(eth->h_source, np->local_mac, 6);
 350         memcpy(eth->h_dest, np->remote_mac, 6);
 351
 352         skb->dev = np->dev;
 353
 354         netpoll_send_skb(np, skb);
 355 }
 356
 357 static void arp_reply(struct sk_buff *skb)
 358 {
 359         struct netpoll_info *npinfo = skb->dev->npinfo;
 360         struct arphdr *arp;
 361         unsigned char *arp_ptr;
 362         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 363         u32 sip, tip;
 364         struct sk_buff *send_skb;
 365         struct netpoll *np = NULL;
 366
 367         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 368                 np = npinfo->rx_np;
 369         if (!np)
 370                 return;
 371
 372         /* No arp on this interface */
 373         if (skb->dev->flags & IFF_NOARP)
 374                 return;
 375
 376         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 377                                  (2 * skb->dev->addr_len) +
 378                                  (2 * sizeof(u32)))))
 379                 return;
 380
 381         skb->h.raw = skb->nh.raw = skb->data;
 382         arp = skb->nh.arph;
 383
 384         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 385              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 386             arp->ar_pro != htons(ETH_P_IP) ||
 387             arp->ar_op != htons(ARPOP_REQUEST))
 388                 return;
 389
 390         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
 391         memcpy(&sip, arp_ptr, 4);
 392         arp_ptr += 4 + skb->dev->addr_len;
 393         memcpy(&tip, arp_ptr, 4);
 394
 395         /* Should we ignore arp? */
 396         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 397                 return;
 398
 399         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 400         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 401                             LL_RESERVED_SPACE(np->dev));
 402
 403         if (!send_skb)
 404                 return;
 405
 406         send_skb->nh.raw = send_skb->data;
 407         arp = (struct arphdr *) skb_put(send_skb, size);
 408         send_skb->dev = skb->dev;
 409         send_skb->protocol = htons(ETH_P_ARP);
 410
 411         /* Fill the device header for the ARP frame */
 412
 413         if (np->dev->hard_header &&
 414             np->dev->hard_header(send_skb, skb->dev, ptype,
 415                                        np->remote_mac, np->local_mac,
 416                                        send_skb->len) < 0) {
 417                 kfree_skb(send_skb);
 418                 return;
 419         }
 420
 421         /*
 422          * Fill out the arp protocol part.
 423          *
 424          * we only support ethernet device type,
 425          * which (according to RFC 1390) should always equal 1 (Ethernet).
 426          */
 427
 428         arp->ar_hrd = htons(np->dev->type);
 429         arp->ar_pro = htons(ETH_P_IP);
 430         arp->ar_hln = np->dev->addr_len;
 431         arp->ar_pln = 4;
 432         arp->ar_op = htons(type);
 433
 434         arp_ptr=(unsigned char *)(arp + 1);
 435         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 436         arp_ptr += np->dev->addr_len;
 437         memcpy(arp_ptr, &tip, 4);
 438         arp_ptr += 4;
 439         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
 440         arp_ptr += np->dev->addr_len;
 441         memcpy(arp_ptr, &sip, 4);
 442
 443         netpoll_send_skb(np, send_skb);
 444 }
 445
 446 int __netpoll_rx(struct sk_buff *skb)
 447 {
 448         int proto, len, ulen;
 449         struct iphdr *iph;
 450         struct udphdr *uh;
 451         struct netpoll *np = skb->dev->npinfo->rx_np;
 452
 453         if (!np)
 454                 goto out;
 455         if (skb->dev->type != ARPHRD_ETHER)
 456                 goto out;
 457
 458         /* check if netpoll clients need ARP */
 459         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 460             atomic_read(&trapped)) {
 461                 arp_reply(skb);
 462                 return 1;
 463         }
 464
 465         proto = ntohs(eth_hdr(skb)->h_proto);
 466         if (proto != ETH_P_IP)
 467                 goto out;
 468         if (skb->pkt_type == PACKET_OTHERHOST)
 469                 goto out;
 470         if (skb_shared(skb))
 471                 goto out;
 472
 473         iph = (struct iphdr *)skb->data;
 474         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 475                 goto out;
 476         if (iph->ihl < 5 || iph->version != 4)
 477                 goto out;
 478         if (!pskb_may_pull(skb, iph->ihl*4))
 479                 goto out;
 480         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 481                 goto out;
 482
 483         len = ntohs(iph->tot_len);
 484         if (skb->len < len || len < iph->ihl*4)
 485                 goto out;
 486
 487         if (iph->protocol != IPPROTO_UDP)
 488                 goto out;
 489
 490         len -= iph->ihl*4;
 491         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 492         ulen = ntohs(uh->len);
 493
 494         if (ulen != len)
 495                 goto out;
 496         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 497                 goto out;
 498         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 499                 goto out;
 500         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 501                 goto out;
 502         if (np->local_port && np->local_port != ntohs(uh->dest))
 503                 goto out;
 504
 505         np->rx_hook(np, ntohs(uh->source),
 506                     (char *)(uh+1),
 507                     ulen - sizeof(struct udphdr));
 508
 509         kfree_skb(skb);
 510         return 1;
 511
 512 out:
 513         if (atomic_read(&trapped)) {
 514                 kfree_skb(skb);
 515                 return 1;
 516         }
 517
 518         return 0;
 519 }
 520
 521 int netpoll_parse_options(struct netpoll *np, char *opt)
 522 {
 523         char *cur=opt, *delim;
 524
 525         if(*cur != '@') {
 526                 if ((delim = strchr(cur, '@')) == NULL)
 527                         goto parse_failed;
 528                 *delim=0;
 529                 np->local_port=simple_strtol(cur, NULL, 10);
 530                 cur=delim;
 531         }
 532         cur++;
 533         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 534
 535         if(*cur != '/') {
 536                 if ((delim = strchr(cur, '/')) == NULL)
 537                         goto parse_failed;
 538                 *delim=0;
 539                 np->local_ip=ntohl(in_aton(cur));
 540                 cur=delim;
 541
 542                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 543                        np->name, HIPQUAD(np->local_ip));
 544         }
 545         cur++;
 546
 547         if ( *cur != ',') {
 548                 /* parse out dev name */
 549                 if ((delim = strchr(cur, ',')) == NULL)
 550                         goto parse_failed;
 551                 *delim=0;
 552                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 553                 cur=delim;
 554         }
 555         cur++;
 556
 557         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 558
 559         if ( *cur != '@' ) {
 560                 /* dst port */
 561                 if ((delim = strchr(cur, '@')) == NULL)
 562                         goto parse_failed;
 563                 *delim=0;
 564                 np->remote_port=simple_strtol(cur, NULL, 10);
 565                 cur=delim;
 566         }
 567         cur++;
 568         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 569
 570         /* dst ip */
 571         if ((delim = strchr(cur, '/')) == NULL)
 572                 goto parse_failed;
 573         *delim=0;
 574         np->remote_ip=ntohl(in_aton(cur));
 575         cur=delim+1;
 576
 577         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 578                        np->name, HIPQUAD(np->remote_ip));
 579
 580         if( *cur != 0 )
 581         {
 582                 /* MAC address */
 583                 if ((delim = strchr(cur, ':')) == NULL)
 584                         goto parse_failed;
 585                 *delim=0;
 586                 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
 587                 cur=delim+1;
 588                 if ((delim = strchr(cur, ':')) == NULL)
 589                         goto parse_failed;
 590                 *delim=0;
 591                 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
 592                 cur=delim+1;
 593                 if ((delim = strchr(cur, ':')) == NULL)
 594                         goto parse_failed;
 595                 *delim=0;
 596                 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
 597                 cur=delim+1;
 598                 if ((delim = strchr(cur, ':')) == NULL)
 599                         goto parse_failed;
 600                 *delim=0;
 601                 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
 602                 cur=delim+1;
 603                 if ((delim = strchr(cur, ':')) == NULL)
 604                         goto parse_failed;
 605                 *delim=0;
 606                 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
 607                 cur=delim+1;
 608                 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
 609         }
 610
 611         printk(KERN_INFO "%s: remote ethernet address "
 612                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 613                np->name,
 614                np->remote_mac[0],
 615                np->remote_mac[1],
 616                np->remote_mac[2],
 617                np->remote_mac[3],
 618                np->remote_mac[4],
 619                np->remote_mac[5]);
 620
 621         return 0;
 622
 623  parse_failed:
 624         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 625                np->name, cur);
 626         return -1;
 627 }
 628
 629 int netpoll_setup(struct netpoll *np)
 630 {
 631         struct net_device *ndev = NULL;
 632         struct in_device *in_dev;
 633         struct netpoll_info *npinfo;
 634         unsigned long flags;
 635
 636         if (np->dev_name)
 637                 ndev = dev_get_by_name(np->dev_name);
 638         if (!ndev) {
 639                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 640                        np->name, np->dev_name);
 641                 return -1;
 642         }
 643
 644         np->dev = ndev;
 645         if (!ndev->npinfo) {
 646                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 647                 if (!npinfo)
 648                         goto release;
 649
 650                 npinfo->rx_flags = 0;
 651                 npinfo->rx_np = NULL;
 652                 spin_lock_init(&npinfo->poll_lock);
 653                 npinfo->poll_owner = -1;
 654                 npinfo->tries = MAX_RETRIES;
 655                 spin_lock_init(&npinfo->rx_lock);
 656         } else
 657                 npinfo = ndev->npinfo;
 658
 659         if (!ndev->poll_controller) {
 660                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 661                        np->name, np->dev_name);
 662                 goto release;
 663         }
 664
 665         if (!netif_running(ndev)) {
 666                 unsigned long atmost, atleast;
 667
 668                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 669                        np->name, np->dev_name);
 670
 671                 rtnl_shlock();
 672                 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
 673                         printk(KERN_ERR "%s: failed to open %s\n",
 674                                np->name, np->dev_name);
 675                         rtnl_shunlock();
 676                         goto release;
 677                 }
 678                 rtnl_shunlock();
 679
 680                 atleast = jiffies + HZ/10;
 681                 atmost = jiffies + 4*HZ;
 682                 while (!netif_carrier_ok(ndev)) {
 683                         if (time_after(jiffies, atmost)) {
 684                                 printk(KERN_NOTICE
 685                                        "%s: timeout waiting for carrier\n",
 686                                        np->name);
 687                                 break;
 688                         }
 689                         cond_resched();
 690                 }
 691
 692                 /* If carrier appears to come up instantly, we don't
 693                  * trust it and pause so that we don't pump all our
 694                  * queued console messages into the bitbucket.
 695                  */
 696
 697                 if (time_before(jiffies, atleast)) {
 698                         printk(KERN_NOTICE "%s: carrier detect appears"
 699                                " untrustworthy, waiting 4 seconds\n",
 700                                np->name);
 701                         msleep(4000);
 702                 }
 703         }
 704
 705         if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
 706                 memcpy(np->local_mac, ndev->dev_addr, 6);
 707
 708         if (!np->local_ip) {
 709                 rcu_read_lock();
 710                 in_dev = __in_dev_get_rcu(ndev);
 711
 712                 if (!in_dev || !in_dev->ifa_list) {
 713                         rcu_read_unlock();
 714                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 715                                np->name, np->dev_name);
 716                         goto release;
 717                 }
 718
 719                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 720                 rcu_read_unlock();
 721                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 722                        np->name, HIPQUAD(np->local_ip));
 723         }
 724
 725         if (np->rx_hook) {
 726                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 727                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 728                 npinfo->rx_np = np;
 729                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 730         }
 731
 732         /* fill up the skb queue */
 733         refill_skbs();
 734
 735         /* last thing to do is link it to the net device structure */
 736         ndev->npinfo = npinfo;
 737
 738         /* avoid racing with NAPI reading npinfo */
 739         synchronize_rcu();
 740
 741         return 0;
 742
 743  release:
 744         if (!ndev->npinfo)
 745                 kfree(npinfo);
 746         np->dev = NULL;
 747         dev_put(ndev);
 748         return -1;
 749 }
 750
 751 void netpoll_cleanup(struct netpoll *np)
 752 {
 753         struct netpoll_info *npinfo;
 754         unsigned long flags;
 755
 756         if (np->dev) {
 757                 npinfo = np->dev->npinfo;
 758                 if (npinfo && npinfo->rx_np == np) {
 759                         spin_lock_irqsave(&npinfo->rx_lock, flags);
 760                         npinfo->rx_np = NULL;
 761                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 762                         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 763                 }
 764                 dev_put(np->dev);
 765         }
 766
 767         np->dev = NULL;
 768 }
 769
 770 int netpoll_trap(void)
 771 {
 772         return atomic_read(&trapped);
 773 }
 774
 775 void netpoll_set_trap(int trap)
 776 {
 777         if (trap)
 778                 atomic_inc(&trapped);
 779         else
 780                 atomic_dec(&trapped);
 781 }
 782
 783 EXPORT_SYMBOL(netpoll_set_trap);
 784 EXPORT_SYMBOL(netpoll_trap);
 785 EXPORT_SYMBOL(netpoll_parse_options);
 786 EXPORT_SYMBOL(netpoll_setup);
 787 EXPORT_SYMBOL(netpoll_cleanup);
 788 EXPORT_SYMBOL(netpoll_send_udp);
 789 EXPORT_SYMBOL(netpoll_poll);
 790 EXPORT_SYMBOL(netpoll_queue);