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