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         if (!np || !np->dev || !netif_running(np->dev)) {
 252                 __kfree_skb(skb);
 253                 return;
 254         }
 255
 256         npinfo = np->dev->npinfo;
 257
 258         /* avoid recursion */
 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         while (1) {
 269                 spin_lock(&np->dev->xmit_lock);
 270                 np->dev->xmit_lock_owner = smp_processor_id();
 271
 272                 /*
 273                  * network drivers do not expect to be called if the queue is
 274                  * stopped.
 275                  */
 276                 if (netif_queue_stopped(np->dev)) {
 277                         np->dev->xmit_lock_owner = -1;
 278                         spin_unlock(&np->dev->xmit_lock);
 279                         netpoll_poll(np);
 280                         continue;
 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                 /* success */
 288                 if(!status)
 289                         return;
 290
 291                 /* transmit busy */
 292                 netpoll_poll(np);
 293         }
 294 }
 295
 296 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 297 {
 298         int total_len, eth_len, ip_len, udp_len;
 299         struct sk_buff *skb;
 300         struct udphdr *udph;
 301         struct iphdr *iph;
 302         struct ethhdr *eth;
 303
 304         udp_len = len + sizeof(*udph);
 305         ip_len = eth_len = udp_len + sizeof(*iph);
 306         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 307
 308         skb = find_skb(np, total_len, total_len - len);
 309         if (!skb)
 310                 return;
 311
 312         memcpy(skb->data, msg, len);
 313         skb->len += len;
 314
 315         udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 316         udph->source = htons(np->local_port);
 317         udph->dest = htons(np->remote_port);
 318         udph->len = htons(udp_len);
 319         udph->check = 0;
 320
 321         iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 322
 323         /* iph->version = 4; iph->ihl = 5; */
 324         put_unaligned(0x45, (unsigned char *)iph);
 325         iph->tos      = 0;
 326         put_unaligned(htons(ip_len), &(iph->tot_len));
 327         iph->id       = 0;
 328         iph->frag_off = 0;
 329         iph->ttl      = 64;
 330         iph->protocol = IPPROTO_UDP;
 331         iph->check    = 0;
 332         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 333         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 334         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 335
 336         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 337
 338         eth->h_proto = htons(ETH_P_IP);
 339         memcpy(eth->h_source, np->local_mac, 6);
 340         memcpy(eth->h_dest, np->remote_mac, 6);
 341
 342         skb->dev = np->dev;
 343
 344         netpoll_send_skb(np, skb);
 345 }
 346
 347 static void arp_reply(struct sk_buff *skb)
 348 {
 349         struct netpoll_info *npinfo = skb->dev->npinfo;
 350         struct arphdr *arp;
 351         unsigned char *arp_ptr;
 352         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 353         u32 sip, tip;
 354         unsigned long flags;
 355         struct sk_buff *send_skb;
 356         struct netpoll *np = NULL;
 357
 358         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 359                 np = npinfo->rx_np;
 360         if (!np)
 361                 return;
 362
 363         /* No arp on this interface */
 364         if (skb->dev->flags & IFF_NOARP)
 365                 return;
 366
 367         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 368                                  (2 * skb->dev->addr_len) +
 369                                  (2 * sizeof(u32)))))
 370                 return;
 371
 372         skb->h.raw = skb->nh.raw = skb->data;
 373         arp = skb->nh.arph;
 374
 375         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 376              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 377             arp->ar_pro != htons(ETH_P_IP) ||
 378             arp->ar_op != htons(ARPOP_REQUEST))
 379                 return;
 380
 381         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
 382         memcpy(&sip, arp_ptr, 4);
 383         arp_ptr += 4 + skb->dev->addr_len;
 384         memcpy(&tip, arp_ptr, 4);
 385
 386         /* Should we ignore arp? */
 387         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 388                 return;
 389
 390         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 391         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 392                             LL_RESERVED_SPACE(np->dev));
 393
 394         if (!send_skb)
 395                 return;
 396
 397         send_skb->nh.raw = send_skb->data;
 398         arp = (struct arphdr *) skb_put(send_skb, size);
 399         send_skb->dev = skb->dev;
 400         send_skb->protocol = htons(ETH_P_ARP);
 401
 402         /* Fill the device header for the ARP frame */
 403
 404         if (np->dev->hard_header &&
 405             np->dev->hard_header(send_skb, skb->dev, ptype,
 406                                        np->remote_mac, np->local_mac,
 407                                        send_skb->len) < 0) {
 408                 kfree_skb(send_skb);
 409                 return;
 410         }
 411
 412         /*
 413          * Fill out the arp protocol part.
 414          *
 415          * we only support ethernet device type,
 416          * which (according to RFC 1390) should always equal 1 (Ethernet).
 417          */
 418
 419         arp->ar_hrd = htons(np->dev->type);
 420         arp->ar_pro = htons(ETH_P_IP);
 421         arp->ar_hln = np->dev->addr_len;
 422         arp->ar_pln = 4;
 423         arp->ar_op = htons(type);
 424
 425         arp_ptr=(unsigned char *)(arp + 1);
 426         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 427         arp_ptr += np->dev->addr_len;
 428         memcpy(arp_ptr, &tip, 4);
 429         arp_ptr += 4;
 430         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
 431         arp_ptr += np->dev->addr_len;
 432         memcpy(arp_ptr, &sip, 4);
 433
 434         netpoll_send_skb(np, send_skb);
 435 }
 436
 437 int __netpoll_rx(struct sk_buff *skb)
 438 {
 439         int proto, len, ulen;
 440         struct iphdr *iph;
 441         struct udphdr *uh;
 442         struct netpoll *np = skb->dev->npinfo->rx_np;
 443
 444         if (!np)
 445                 goto out;
 446         if (skb->dev->type != ARPHRD_ETHER)
 447                 goto out;
 448
 449         /* check if netpoll clients need ARP */
 450         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 451             atomic_read(&trapped)) {
 452                 arp_reply(skb);
 453                 return 1;
 454         }
 455
 456         proto = ntohs(eth_hdr(skb)->h_proto);
 457         if (proto != ETH_P_IP)
 458                 goto out;
 459         if (skb->pkt_type == PACKET_OTHERHOST)
 460                 goto out;
 461         if (skb_shared(skb))
 462                 goto out;
 463
 464         iph = (struct iphdr *)skb->data;
 465         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 466                 goto out;
 467         if (iph->ihl < 5 || iph->version != 4)
 468                 goto out;
 469         if (!pskb_may_pull(skb, iph->ihl*4))
 470                 goto out;
 471         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 472                 goto out;
 473
 474         len = ntohs(iph->tot_len);
 475         if (skb->len < len || len < iph->ihl*4)
 476                 goto out;
 477
 478         if (iph->protocol != IPPROTO_UDP)
 479                 goto out;
 480
 481         len -= iph->ihl*4;
 482         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 483         ulen = ntohs(uh->len);
 484
 485         if (ulen != len)
 486                 goto out;
 487         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr) < 0)
 488                 goto out;
 489         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 490                 goto out;
 491         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 492                 goto out;
 493         if (np->local_port && np->local_port != ntohs(uh->dest))
 494                 goto out;
 495
 496         np->rx_hook(np, ntohs(uh->source),
 497                     (char *)(uh+1),
 498                     ulen - sizeof(struct udphdr));
 499
 500         kfree_skb(skb);
 501         return 1;
 502
 503 out:
 504         if (atomic_read(&trapped)) {
 505                 kfree_skb(skb);
 506                 return 1;
 507         }
 508
 509         return 0;
 510 }
 511
 512 int netpoll_parse_options(struct netpoll *np, char *opt)
 513 {
 514         char *cur=opt, *delim;
 515
 516         if(*cur != '@') {
 517                 if ((delim = strchr(cur, '@')) == NULL)
 518                         goto parse_failed;
 519                 *delim=0;
 520                 np->local_port=simple_strtol(cur, NULL, 10);
 521                 cur=delim;
 522         }
 523         cur++;
 524         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 525
 526         if(*cur != '/') {
 527                 if ((delim = strchr(cur, '/')) == NULL)
 528                         goto parse_failed;
 529                 *delim=0;
 530                 np->local_ip=ntohl(in_aton(cur));
 531                 cur=delim;
 532
 533                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 534                        np->name, HIPQUAD(np->local_ip));
 535         }
 536         cur++;
 537
 538         if ( *cur != ',') {
 539                 /* parse out dev name */
 540                 if ((delim = strchr(cur, ',')) == NULL)
 541                         goto parse_failed;
 542                 *delim=0;
 543                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 544                 cur=delim;
 545         }
 546         cur++;
 547
 548         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 549
 550         if ( *cur != '@' ) {
 551                 /* dst port */
 552                 if ((delim = strchr(cur, '@')) == NULL)
 553                         goto parse_failed;
 554                 *delim=0;
 555                 np->remote_port=simple_strtol(cur, NULL, 10);
 556                 cur=delim;
 557         }
 558         cur++;
 559         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 560
 561         /* dst ip */
 562         if ((delim = strchr(cur, '/')) == NULL)
 563                 goto parse_failed;
 564         *delim=0;
 565         np->remote_ip=ntohl(in_aton(cur));
 566         cur=delim+1;
 567
 568         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 569                        np->name, HIPQUAD(np->remote_ip));
 570
 571         if( *cur != 0 )
 572         {
 573                 /* MAC address */
 574                 if ((delim = strchr(cur, ':')) == NULL)
 575                         goto parse_failed;
 576                 *delim=0;
 577                 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
 578                 cur=delim+1;
 579                 if ((delim = strchr(cur, ':')) == NULL)
 580                         goto parse_failed;
 581                 *delim=0;
 582                 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
 583                 cur=delim+1;
 584                 if ((delim = strchr(cur, ':')) == NULL)
 585                         goto parse_failed;
 586                 *delim=0;
 587                 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
 588                 cur=delim+1;
 589                 if ((delim = strchr(cur, ':')) == NULL)
 590                         goto parse_failed;
 591                 *delim=0;
 592                 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
 593                 cur=delim+1;
 594                 if ((delim = strchr(cur, ':')) == NULL)
 595                         goto parse_failed;
 596                 *delim=0;
 597                 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
 598                 cur=delim+1;
 599                 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
 600         }
 601
 602         printk(KERN_INFO "%s: remote ethernet address "
 603                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 604                np->name,
 605                np->remote_mac[0],
 606                np->remote_mac[1],
 607                np->remote_mac[2],
 608                np->remote_mac[3],
 609                np->remote_mac[4],
 610                np->remote_mac[5]);
 611
 612         return 0;
 613
 614  parse_failed:
 615         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 616                np->name, cur);
 617         return -1;
 618 }
 619
 620 int netpoll_setup(struct netpoll *np)
 621 {
 622         struct net_device *ndev = NULL;
 623         struct in_device *in_dev;
 624         struct netpoll_info *npinfo;
 625         unsigned long flags;
 626
 627         if (np->dev_name)
 628                 ndev = dev_get_by_name(np->dev_name);
 629         if (!ndev) {
 630                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 631                        np->name, np->dev_name);
 632                 return -1;
 633         }
 634
 635         np->dev = ndev;
 636         if (!ndev->npinfo) {
 637                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 638                 if (!npinfo)
 639                         goto release;
 640
 641                 npinfo->rx_flags = 0;
 642                 npinfo->rx_np = NULL;
 643                 npinfo->poll_lock = SPIN_LOCK_UNLOCKED;
 644                 npinfo->poll_owner = -1;
 645                 npinfo->rx_lock = SPIN_LOCK_UNLOCKED;
 646         } else
 647                 npinfo = ndev->npinfo;
 648
 649         if (!ndev->poll_controller) {
 650                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 651                        np->name, np->dev_name);
 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_shlock();
 662                 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
 663                         printk(KERN_ERR "%s: failed to open %s\n",
 664                                np->name, np->dev_name);
 665                         rtnl_shunlock();
 666                         goto release;
 667                 }
 668                 rtnl_shunlock();
 669
 670                 atleast = jiffies + HZ/10;
 671                 atmost = jiffies + 4*HZ;
 672                 while (!netif_carrier_ok(ndev)) {
 673                         if (time_after(jiffies, atmost)) {
 674                                 printk(KERN_NOTICE
 675                                        "%s: timeout waiting for carrier\n",
 676                                        np->name);
 677                                 break;
 678                         }
 679                         cond_resched();
 680                 }
 681
 682                 /* If carrier appears to come up instantly, we don't
 683                  * trust it and pause so that we don't pump all our
 684                  * queued console messages into the bitbucket.
 685                  */
 686
 687                 if (time_before(jiffies, atleast)) {
 688                         printk(KERN_NOTICE "%s: carrier detect appears"
 689                                " untrustworthy, waiting 4 seconds\n",
 690                                np->name);
 691                         msleep(4000);
 692                 }
 693         }
 694
 695         if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
 696                 memcpy(np->local_mac, ndev->dev_addr, 6);
 697
 698         if (!np->local_ip) {
 699                 rcu_read_lock();
 700                 in_dev = __in_dev_get(ndev);
 701
 702                 if (!in_dev || !in_dev->ifa_list) {
 703                         rcu_read_unlock();
 704                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 705                                np->name, np->dev_name);
 706                         goto release;
 707                 }
 708
 709                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 710                 rcu_read_unlock();
 711                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 712                        np->name, HIPQUAD(np->local_ip));
 713         }
 714
 715         if (np->rx_hook) {
 716                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 717                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 718                 npinfo->rx_np = np;
 719                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 720         }
 721         /* last thing to do is link it to the net device structure */
 722         ndev->npinfo = npinfo;
 723
 724         return 0;
 725
 726  release:
 727         if (!ndev->npinfo)
 728                 kfree(npinfo);
 729         np->dev = NULL;
 730         dev_put(ndev);
 731         return -1;
 732 }
 733
 734 void netpoll_cleanup(struct netpoll *np)
 735 {
 736         struct netpoll_info *npinfo;
 737         unsigned long flags;
 738
 739         if (np->dev) {
 740                 npinfo = np->dev->npinfo;
 741                 if (npinfo && npinfo->rx_np == np) {
 742                         spin_lock_irqsave(&npinfo->rx_lock, flags);
 743                         npinfo->rx_np = NULL;
 744                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 745                         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 746                 }
 747                 dev_put(np->dev);
 748         }
 749
 750         np->dev = NULL;
 751 }
 752
 753 int netpoll_trap(void)
 754 {
 755         return atomic_read(&trapped);
 756 }
 757
 758 void netpoll_set_trap(int trap)
 759 {
 760         if (trap)
 761                 atomic_inc(&trapped);
 762         else
 763                 atomic_dec(&trapped);
 764 }
 765
 766 EXPORT_SYMBOL(netpoll_set_trap);
 767 EXPORT_SYMBOL(netpoll_trap);
 768 EXPORT_SYMBOL(netpoll_parse_options);
 769 EXPORT_SYMBOL(netpoll_setup);
 770 EXPORT_SYMBOL(netpoll_cleanup);
 771 EXPORT_SYMBOL(netpoll_send_udp);
 772 EXPORT_SYMBOL(netpoll_poll);
 773 EXPORT_SYMBOL(netpoll_queue);