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