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 #define MAX_RETRIES 20000
  38
  39 static struct sk_buff_head skb_pool;
  40
  41 static DEFINE_SPINLOCK(queue_lock);
  42 static int queue_depth;
  43 static struct sk_buff *queue_head, *queue_tail;
  44
  45 static atomic_t trapped;
  46
  47 #define NETPOLL_RX_ENABLED  1
  48 #define NETPOLL_RX_DROP     2
  49
  50 #define MAX_SKB_SIZE \
  51                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  52                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  53
  54 static void zap_completion_queue(void);
  55 static void arp_reply(struct sk_buff *skb);
  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_COMPLETE &&
 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 static void service_arp_queue(struct netpoll_info *npi)
 156 {
 157         struct sk_buff *skb;
 158
 159         if (unlikely(!npi))
 160                 return;
 161
 162         skb = skb_dequeue(&npi->arp_tx);
 163
 164         while (skb != NULL) {
 165                 arp_reply(skb);
 166                 skb = skb_dequeue(&npi->arp_tx);
 167         }
 168         return;
 169 }
 170
 171 void netpoll_poll(struct netpoll *np)
 172 {
 173         if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
 174                 return;
 175
 176         /* Process pending work on NIC */
 177         np->dev->poll_controller(np->dev);
 178         if (np->dev->poll)
 179                 poll_napi(np);
 180
 181         service_arp_queue(np->dev->npinfo);
 182
 183         zap_completion_queue();
 184 }
 185
 186 static void refill_skbs(void)
 187 {
 188         struct sk_buff *skb;
 189         unsigned long flags;
 190
 191         spin_lock_irqsave(&skb_pool.lock, flags);
 192         while (skb_pool.qlen < MAX_SKBS) {
 193                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 194                 if (!skb)
 195                         break;
 196
 197                 __skb_queue_tail(&skb_pool, skb);
 198         }
 199         spin_unlock_irqrestore(&skb_pool.lock, flags);
 200 }
 201
 202 static void zap_completion_queue(void)
 203 {
 204         unsigned long flags;
 205         struct softnet_data *sd = &get_cpu_var(softnet_data);
 206
 207         if (sd->completion_queue) {
 208                 struct sk_buff *clist;
 209
 210                 local_irq_save(flags);
 211                 clist = sd->completion_queue;
 212                 sd->completion_queue = NULL;
 213                 local_irq_restore(flags);
 214
 215                 while (clist != NULL) {
 216                         struct sk_buff *skb = clist;
 217                         clist = clist->next;
 218                         if(skb->destructor)
 219                                 dev_kfree_skb_any(skb); /* put this one back */
 220                         else
 221                                 __kfree_skb(skb);
 222                 }
 223         }
 224
 225         put_cpu_var(softnet_data);
 226 }
 227
 228 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 229 {
 230         int count = 0;
 231         struct sk_buff *skb;
 232
 233         zap_completion_queue();
 234         refill_skbs();
 235 repeat:
 236
 237         skb = alloc_skb(len, GFP_ATOMIC);
 238         if (!skb)
 239                 skb = skb_dequeue(&skb_pool);
 240
 241         if(!skb) {
 242                 if (++count < 10) {
 243                         netpoll_poll(np);
 244                         goto repeat;
 245                 }
 246                 return NULL;
 247         }
 248
 249         atomic_set(&skb->users, 1);
 250         skb_reserve(skb, reserve);
 251         return skb;
 252 }
 253
 254 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 255 {
 256         int status;
 257         struct netpoll_info *npinfo;
 258
 259         if (!np || !np->dev || !netif_running(np->dev)) {
 260                 __kfree_skb(skb);
 261                 return;
 262         }
 263
 264         npinfo = np->dev->npinfo;
 265
 266         /* avoid recursion */
 267         if (npinfo->poll_owner == smp_processor_id() ||
 268             np->dev->xmit_lock_owner == smp_processor_id()) {
 269                 if (np->drop)
 270                         np->drop(skb);
 271                 else
 272                         __kfree_skb(skb);
 273                 return;
 274         }
 275
 276         do {
 277                 npinfo->tries--;
 278                 netif_tx_lock(np->dev);
 279
 280                 /*
 281                  * network drivers do not expect to be called if the queue is
 282                  * stopped.
 283                  */
 284                 status = NETDEV_TX_BUSY;
 285                 if (!netif_queue_stopped(np->dev))
 286                         status = np->dev->hard_start_xmit(skb, np->dev);
 287
 288                 netif_tx_unlock(np->dev);
 289
 290                 /* success */
 291                 if(!status) {
 292                         npinfo->tries = MAX_RETRIES; /* reset */
 293                         return;
 294                 }
 295
 296                 /* transmit busy */
 297                 netpoll_poll(np);
 298                 udelay(50);
 299         } while (npinfo->tries > 0);
 300 }
 301
 302 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 303 {
 304         int total_len, eth_len, ip_len, udp_len;
 305         struct sk_buff *skb;
 306         struct udphdr *udph;
 307         struct iphdr *iph;
 308         struct ethhdr *eth;
 309
 310         udp_len = len + sizeof(*udph);
 311         ip_len = eth_len = udp_len + sizeof(*iph);
 312         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 313
 314         skb = find_skb(np, total_len, total_len - len);
 315         if (!skb)
 316                 return;
 317
 318         memcpy(skb->data, msg, len);
 319         skb->len += len;
 320
 321         skb->h.uh = udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 322         udph->source = htons(np->local_port);
 323         udph->dest = htons(np->remote_port);
 324         udph->len = htons(udp_len);
 325         udph->check = 0;
 326         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
 327                                         htonl(np->remote_ip),
 328                                         udp_len, IPPROTO_UDP,
 329                                         csum_partial((unsigned char *)udph, udp_len, 0));
 330         if (udph->check == 0)
 331                 udph->check = -1;
 332
 333         skb->nh.iph = iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 334
 335         /* iph->version = 4; iph->ihl = 5; */
 336         put_unaligned(0x45, (unsigned char *)iph);
 337         iph->tos      = 0;
 338         put_unaligned(htons(ip_len), &(iph->tot_len));
 339         iph->id       = 0;
 340         iph->frag_off = 0;
 341         iph->ttl      = 64;
 342         iph->protocol = IPPROTO_UDP;
 343         iph->check    = 0;
 344         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 345         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 346         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 347
 348         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 349         skb->mac.raw = skb->data;
 350         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 351         memcpy(eth->h_source, np->local_mac, 6);
 352         memcpy(eth->h_dest, np->remote_mac, 6);
 353
 354         skb->dev = np->dev;
 355
 356         netpoll_send_skb(np, skb);
 357 }
 358
 359 static void arp_reply(struct sk_buff *skb)
 360 {
 361         struct netpoll_info *npinfo = skb->dev->npinfo;
 362         struct arphdr *arp;
 363         unsigned char *arp_ptr;
 364         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 365         u32 sip, tip;
 366         struct sk_buff *send_skb;
 367         struct netpoll *np = NULL;
 368
 369         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 370                 np = npinfo->rx_np;
 371         if (!np)
 372                 return;
 373
 374         /* No arp on this interface */
 375         if (skb->dev->flags & IFF_NOARP)
 376                 return;
 377
 378         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 379                                  (2 * skb->dev->addr_len) +
 380                                  (2 * sizeof(u32)))))
 381                 return;
 382
 383         skb->h.raw = skb->nh.raw = skb->data;
 384         arp = skb->nh.arph;
 385
 386         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 387              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 388             arp->ar_pro != htons(ETH_P_IP) ||
 389             arp->ar_op != htons(ARPOP_REQUEST))
 390                 return;
 391
 392         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
 393         memcpy(&sip, arp_ptr, 4);
 394         arp_ptr += 4 + skb->dev->addr_len;
 395         memcpy(&tip, arp_ptr, 4);
 396
 397         /* Should we ignore arp? */
 398         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 399                 return;
 400
 401         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 402         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 403                             LL_RESERVED_SPACE(np->dev));
 404
 405         if (!send_skb)
 406                 return;
 407
 408         send_skb->nh.raw = send_skb->data;
 409         arp = (struct arphdr *) skb_put(send_skb, size);
 410         send_skb->dev = skb->dev;
 411         send_skb->protocol = htons(ETH_P_ARP);
 412
 413         /* Fill the device header for the ARP frame */
 414
 415         if (np->dev->hard_header &&
 416             np->dev->hard_header(send_skb, skb->dev, ptype,
 417                                        np->remote_mac, np->local_mac,
 418                                        send_skb->len) < 0) {
 419                 kfree_skb(send_skb);
 420                 return;
 421         }
 422
 423         /*
 424          * Fill out the arp protocol part.
 425          *
 426          * we only support ethernet device type,
 427          * which (according to RFC 1390) should always equal 1 (Ethernet).
 428          */
 429
 430         arp->ar_hrd = htons(np->dev->type);
 431         arp->ar_pro = htons(ETH_P_IP);
 432         arp->ar_hln = np->dev->addr_len;
 433         arp->ar_pln = 4;
 434         arp->ar_op = htons(type);
 435
 436         arp_ptr=(unsigned char *)(arp + 1);
 437         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 438         arp_ptr += np->dev->addr_len;
 439         memcpy(arp_ptr, &tip, 4);
 440         arp_ptr += 4;
 441         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
 442         arp_ptr += np->dev->addr_len;
 443         memcpy(arp_ptr, &sip, 4);
 444
 445         netpoll_send_skb(np, send_skb);
 446 }
 447
 448 int __netpoll_rx(struct sk_buff *skb)
 449 {
 450         int proto, len, ulen;
 451         struct iphdr *iph;
 452         struct udphdr *uh;
 453         struct netpoll_info *npi = skb->dev->npinfo;
 454         struct netpoll *np = npi->rx_np;
 455
 456
 457         if (!np)
 458                 goto out;
 459         if (skb->dev->type != ARPHRD_ETHER)
 460                 goto out;
 461
 462         /* check if netpoll clients need ARP */
 463         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 464             atomic_read(&trapped)) {
 465                 skb_queue_tail(&npi->arp_tx, skb);
 466                 return 1;
 467         }
 468
 469         proto = ntohs(eth_hdr(skb)->h_proto);
 470         if (proto != ETH_P_IP)
 471                 goto out;
 472         if (skb->pkt_type == PACKET_OTHERHOST)
 473                 goto out;
 474         if (skb_shared(skb))
 475                 goto out;
 476
 477         iph = (struct iphdr *)skb->data;
 478         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 479                 goto out;
 480         if (iph->ihl < 5 || iph->version != 4)
 481                 goto out;
 482         if (!pskb_may_pull(skb, iph->ihl*4))
 483                 goto out;
 484         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 485                 goto out;
 486
 487         len = ntohs(iph->tot_len);
 488         if (skb->len < len || len < iph->ihl*4)
 489                 goto out;
 490
 491         if (iph->protocol != IPPROTO_UDP)
 492                 goto out;
 493
 494         len -= iph->ihl*4;
 495         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 496         ulen = ntohs(uh->len);
 497
 498         if (ulen != len)
 499                 goto out;
 500         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 501                 goto out;
 502         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 503                 goto out;
 504         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 505                 goto out;
 506         if (np->local_port && np->local_port != ntohs(uh->dest))
 507                 goto out;
 508
 509         np->rx_hook(np, ntohs(uh->source),
 510                     (char *)(uh+1),
 511                     ulen - sizeof(struct udphdr));
 512
 513         kfree_skb(skb);
 514         return 1;
 515
 516 out:
 517         if (atomic_read(&trapped)) {
 518                 kfree_skb(skb);
 519                 return 1;
 520         }
 521
 522         return 0;
 523 }
 524
 525 int netpoll_parse_options(struct netpoll *np, char *opt)
 526 {
 527         char *cur=opt, *delim;
 528
 529         if(*cur != '@') {
 530                 if ((delim = strchr(cur, '@')) == NULL)
 531                         goto parse_failed;
 532                 *delim=0;
 533                 np->local_port=simple_strtol(cur, NULL, 10);
 534                 cur=delim;
 535         }
 536         cur++;
 537         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 538
 539         if(*cur != '/') {
 540                 if ((delim = strchr(cur, '/')) == NULL)
 541                         goto parse_failed;
 542                 *delim=0;
 543                 np->local_ip=ntohl(in_aton(cur));
 544                 cur=delim;
 545
 546                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 547                        np->name, HIPQUAD(np->local_ip));
 548         }
 549         cur++;
 550
 551         if ( *cur != ',') {
 552                 /* parse out dev name */
 553                 if ((delim = strchr(cur, ',')) == NULL)
 554                         goto parse_failed;
 555                 *delim=0;
 556                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 557                 cur=delim;
 558         }
 559         cur++;
 560
 561         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 562
 563         if ( *cur != '@' ) {
 564                 /* dst port */
 565                 if ((delim = strchr(cur, '@')) == NULL)
 566                         goto parse_failed;
 567                 *delim=0;
 568                 np->remote_port=simple_strtol(cur, NULL, 10);
 569                 cur=delim;
 570         }
 571         cur++;
 572         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 573
 574         /* dst ip */
 575         if ((delim = strchr(cur, '/')) == NULL)
 576                 goto parse_failed;
 577         *delim=0;
 578         np->remote_ip=ntohl(in_aton(cur));
 579         cur=delim+1;
 580
 581         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 582                        np->name, HIPQUAD(np->remote_ip));
 583
 584         if( *cur != 0 )
 585         {
 586                 /* MAC address */
 587                 if ((delim = strchr(cur, ':')) == NULL)
 588                         goto parse_failed;
 589                 *delim=0;
 590                 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
 591                 cur=delim+1;
 592                 if ((delim = strchr(cur, ':')) == NULL)
 593                         goto parse_failed;
 594                 *delim=0;
 595                 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
 596                 cur=delim+1;
 597                 if ((delim = strchr(cur, ':')) == NULL)
 598                         goto parse_failed;
 599                 *delim=0;
 600                 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
 601                 cur=delim+1;
 602                 if ((delim = strchr(cur, ':')) == NULL)
 603                         goto parse_failed;
 604                 *delim=0;
 605                 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
 606                 cur=delim+1;
 607                 if ((delim = strchr(cur, ':')) == NULL)
 608                         goto parse_failed;
 609                 *delim=0;
 610                 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
 611                 cur=delim+1;
 612                 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
 613         }
 614
 615         printk(KERN_INFO "%s: remote ethernet address "
 616                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 617                np->name,
 618                np->remote_mac[0],
 619                np->remote_mac[1],
 620                np->remote_mac[2],
 621                np->remote_mac[3],
 622                np->remote_mac[4],
 623                np->remote_mac[5]);
 624
 625         return 0;
 626
 627  parse_failed:
 628         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 629                np->name, cur);
 630         return -1;
 631 }
 632
 633 int netpoll_setup(struct netpoll *np)
 634 {
 635         struct net_device *ndev = NULL;
 636         struct in_device *in_dev;
 637         struct netpoll_info *npinfo;
 638         unsigned long flags;
 639
 640         if (np->dev_name)
 641                 ndev = dev_get_by_name(np->dev_name);
 642         if (!ndev) {
 643                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 644                        np->name, np->dev_name);
 645                 return -1;
 646         }
 647
 648         np->dev = ndev;
 649         if (!ndev->npinfo) {
 650                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 651                 if (!npinfo)
 652                         goto release;
 653
 654                 npinfo->rx_flags = 0;
 655                 npinfo->rx_np = NULL;
 656                 spin_lock_init(&npinfo->poll_lock);
 657                 npinfo->poll_owner = -1;
 658                 npinfo->tries = MAX_RETRIES;
 659                 spin_lock_init(&npinfo->rx_lock);
 660                 skb_queue_head_init(&npinfo->arp_tx);
 661         } else
 662                 npinfo = ndev->npinfo;
 663
 664         if (!ndev->poll_controller) {
 665                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 666                        np->name, np->dev_name);
 667                 goto release;
 668         }
 669
 670         if (!netif_running(ndev)) {
 671                 unsigned long atmost, atleast;
 672
 673                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 674                        np->name, np->dev_name);
 675
 676                 rtnl_lock();
 677                 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
 678                         printk(KERN_ERR "%s: failed to open %s\n",
 679                                np->name, np->dev_name);
 680                         rtnl_unlock();
 681                         goto release;
 682                 }
 683                 rtnl_unlock();
 684
 685                 atleast = jiffies + HZ/10;
 686                 atmost = jiffies + 4*HZ;
 687                 while (!netif_carrier_ok(ndev)) {
 688                         if (time_after(jiffies, atmost)) {
 689                                 printk(KERN_NOTICE
 690                                        "%s: timeout waiting for carrier\n",
 691                                        np->name);
 692                                 break;
 693                         }
 694                         cond_resched();
 695                 }
 696
 697                 /* If carrier appears to come up instantly, we don't
 698                  * trust it and pause so that we don't pump all our
 699                  * queued console messages into the bitbucket.
 700                  */
 701
 702                 if (time_before(jiffies, atleast)) {
 703                         printk(KERN_NOTICE "%s: carrier detect appears"
 704                                " untrustworthy, waiting 4 seconds\n",
 705                                np->name);
 706                         msleep(4000);
 707                 }
 708         }
 709
 710         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
 711                 memcpy(np->local_mac, ndev->dev_addr, 6);
 712
 713         if (!np->local_ip) {
 714                 rcu_read_lock();
 715                 in_dev = __in_dev_get_rcu(ndev);
 716
 717                 if (!in_dev || !in_dev->ifa_list) {
 718                         rcu_read_unlock();
 719                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 720                                np->name, np->dev_name);
 721                         goto release;
 722                 }
 723
 724                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 725                 rcu_read_unlock();
 726                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 727                        np->name, HIPQUAD(np->local_ip));
 728         }
 729
 730         if (np->rx_hook) {
 731                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 732                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 733                 npinfo->rx_np = np;
 734                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 735         }
 736
 737         /* fill up the skb queue */
 738         refill_skbs();
 739
 740         /* last thing to do is link it to the net device structure */
 741         ndev->npinfo = npinfo;
 742
 743         /* avoid racing with NAPI reading npinfo */
 744         synchronize_rcu();
 745
 746         return 0;
 747
 748  release:
 749         if (!ndev->npinfo)
 750                 kfree(npinfo);
 751         np->dev = NULL;
 752         dev_put(ndev);
 753         return -1;
 754 }
 755
 756 static int __init netpoll_init(void) {
 757         skb_queue_head_init(&skb_pool);
 758         return 0;
 759 }
 760 core_initcall(netpoll_init);
 761
 762 void netpoll_cleanup(struct netpoll *np)
 763 {
 764         struct netpoll_info *npinfo;
 765         unsigned long flags;
 766
 767         if (np->dev) {
 768                 npinfo = np->dev->npinfo;
 769                 if (npinfo && npinfo->rx_np == np) {
 770                         spin_lock_irqsave(&npinfo->rx_lock, flags);
 771                         npinfo->rx_np = NULL;
 772                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 773                         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 774                 }
 775                 dev_put(np->dev);
 776         }
 777
 778         np->dev = NULL;
 779 }
 780
 781 int netpoll_trap(void)
 782 {
 783         return atomic_read(&trapped);
 784 }
 785
 786 void netpoll_set_trap(int trap)
 787 {
 788         if (trap)
 789                 atomic_inc(&trapped);
 790         else
 791                 atomic_dec(&trapped);
 792 }
 793
 794 EXPORT_SYMBOL(netpoll_set_trap);
 795 EXPORT_SYMBOL(netpoll_trap);
 796 EXPORT_SYMBOL(netpoll_parse_options);
 797 EXPORT_SYMBOL(netpoll_setup);
 798 EXPORT_SYMBOL(netpoll_cleanup);
 799 EXPORT_SYMBOL(netpoll_send_udp);
 800 EXPORT_SYMBOL(netpoll_poll);
 801 EXPORT_SYMBOL(netpoll_queue);