net/core/netpoll.c

   1 /*
   2  * Common framework for low-level network console, dump, and debugger code
   3  *
   4  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
   5  *
   6  * based on the netconsole code from:
   7  *
   8  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
   9  * Copyright (C) 2002  Red Hat, Inc.
  10  */
  11
  12 #include <linux/smp_lock.h>
  13 #include <linux/netdevice.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/string.h>
  16 #include <linux/inetdevice.h>
  17 #include <linux/inet.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/netpoll.h>
  20 #include <linux/sched.h>
  21 #include <linux/delay.h>
  22 #include <linux/rcupdate.h>
  23 #include <linux/workqueue.h>
  24 #include <net/tcp.h>
  25 #include <net/udp.h>
  26 #include <asm/unaligned.h>
  27
  28 /*
  29  * We maintain a small pool of fully-sized skbs, to make sure the
  30  * message gets out even in extreme OOM situations.
  31  */
  32
  33 #define MAX_UDP_CHUNK 1460
  34 #define MAX_SKBS 32
  35 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
  36 #define MAX_RETRIES 20000
  37
  38 static DEFINE_SPINLOCK(skb_list_lock);
  39 static int nr_skbs;
  40 static struct sk_buff *skbs;
  41
  42 static DEFINE_SPINLOCK(queue_lock);
  43 static int queue_depth;
  44 static struct sk_buff *queue_head, *queue_tail;
  45
  46 static atomic_t trapped;
  47
  48 #define NETPOLL_RX_ENABLED  1
  49 #define NETPOLL_RX_DROP     2
  50
  51 #define MAX_SKB_SIZE \
  52                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  53                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  54
  55 static void zap_completion_queue(void);
  56
  57 static void queue_process(void *p)
  58 {
  59         unsigned long flags;
  60         struct sk_buff *skb;
  61
  62         while (queue_head) {
  63                 spin_lock_irqsave(&queue_lock, flags);
  64
  65                 skb = queue_head;
  66                 queue_head = skb->next;
  67                 if (skb == queue_tail)
  68                         queue_head = NULL;
  69
  70                 queue_depth--;
  71
  72                 spin_unlock_irqrestore(&queue_lock, flags);
  73
  74                 dev_queue_xmit(skb);
  75         }
  76 }
  77
  78 static DECLARE_WORK(send_queue, queue_process, NULL);
  79
  80 void netpoll_queue(struct sk_buff *skb)
  81 {
  82         unsigned long flags;
  83
  84         if (queue_depth == MAX_QUEUE_DEPTH) {
  85                 __kfree_skb(skb);
  86                 return;
  87         }
  88
  89         spin_lock_irqsave(&queue_lock, flags);
  90         if (!queue_head)
  91                 queue_head = skb;
  92         else
  93                 queue_tail->next = skb;
  94         queue_tail = skb;
  95         queue_depth++;
  96         spin_unlock_irqrestore(&queue_lock, flags);
  97
  98         schedule_work(&send_queue);
  99 }
 100
 101 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 102                              unsigned short ulen, u32 saddr, u32 daddr)
 103 {
 104         if (uh->check == 0)
 105                 return 0;
 106
 107         if (skb->ip_summed == CHECKSUM_HW)
 108                 return csum_tcpudp_magic(
 109                         saddr, daddr, ulen, IPPROTO_UDP, skb->csum);
 110
 111         skb->csum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 112
 113         return csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
 114 }
 115
 116 /*
 117  * Check whether delayed processing was scheduled for our NIC. If so,
 118  * we attempt to grab the poll lock and use ->poll() to pump the card.
 119  * If this fails, either we've recursed in ->poll() or it's already
 120  * running on another CPU.
 121  *
 122  * Note: we don't mask interrupts with this lock because we're using
 123  * trylock here and interrupts are already disabled in the softirq
 124  * case. Further, we test the poll_owner to avoid recursion on UP
 125  * systems where the lock doesn't exist.
 126  *
 127  * In cases where there is bi-directional communications, reading only
 128  * one message at a time can lead to packets being dropped by the
 129  * network adapter, forcing superfluous retries and possibly timeouts.
 130  * Thus, we set our budget to greater than 1.
 131  */
 132 static void poll_napi(struct netpoll *np)
 133 {
 134         struct netpoll_info *npinfo = np->dev->npinfo;
 135         int budget = 16;
 136
 137         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
 138             npinfo->poll_owner != smp_processor_id() &&
 139             spin_trylock(&npinfo->poll_lock)) {
 140                 npinfo->rx_flags |= NETPOLL_RX_DROP;
 141                 atomic_inc(&trapped);
 142
 143                 np->dev->poll(np->dev, &budget);
 144
 145                 atomic_dec(&trapped);
 146                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 147                 spin_unlock(&npinfo->poll_lock);
 148         }
 149 }
 150
 151 void netpoll_poll(struct netpoll *np)
 152 {
 153         if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
 154                 return;
 155
 156         /* Process pending work on NIC */
 157         np->dev->poll_controller(np->dev);
 158         if (np->dev->poll)
 159                 poll_napi(np);
 160
 161         zap_completion_queue();
 162 }
 163
 164 static void refill_skbs(void)
 165 {
 166         struct sk_buff *skb;
 167         unsigned long flags;
 168
 169         spin_lock_irqsave(&skb_list_lock, flags);
 170         while (nr_skbs < MAX_SKBS) {
 171                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 172                 if (!skb)
 173                         break;
 174
 175                 skb->next = skbs;
 176                 skbs = skb;
 177                 nr_skbs++;
 178         }
 179         spin_unlock_irqrestore(&skb_list_lock, flags);
 180 }
 181
 182 static void zap_completion_queue(void)
 183 {
 184         unsigned long flags;
 185         struct softnet_data *sd = &get_cpu_var(softnet_data);
 186
 187         if (sd->completion_queue) {
 188                 struct sk_buff *clist;
 189
 190                 local_irq_save(flags);
 191                 clist = sd->completion_queue;
 192                 sd->completion_queue = NULL;
 193                 local_irq_restore(flags);
 194
 195                 while (clist != NULL) {
 196                         struct sk_buff *skb = clist;
 197                         clist = clist->next;
 198                         if(skb->destructor)
 199                                 dev_kfree_skb_any(skb); /* put this one back */
 200                         else
 201                                 __kfree_skb(skb);
 202                 }
 203         }
 204
 205         put_cpu_var(softnet_data);
 206 }
 207
 208 static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
 209 {
 210         int once = 1, count = 0;
 211         unsigned long flags;
 212         struct sk_buff *skb = NULL;
 213
 214         zap_completion_queue();
 215 repeat:
 216         if (nr_skbs < MAX_SKBS)
 217                 refill_skbs();
 218
 219         skb = alloc_skb(len, GFP_ATOMIC);
 220
 221         if (!skb) {
 222                 spin_lock_irqsave(&skb_list_lock, flags);
 223                 skb = skbs;
 224                 if (skb) {
 225                         skbs = skb->next;
 226                         skb->next = NULL;
 227                         nr_skbs--;
 228                 }
 229                 spin_unlock_irqrestore(&skb_list_lock, flags);
 230         }
 231
 232         if(!skb) {
 233                 count++;
 234                 if (once && (count == 1000000)) {
 235                         printk("out of netpoll skbs!\n");
 236                         once = 0;
 237                 }
 238                 netpoll_poll(np);
 239                 goto repeat;
 240         }
 241
 242         atomic_set(&skb->users, 1);
 243         skb_reserve(skb, reserve);
 244         return skb;
 245 }
 246
 247 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 248 {
 249         int status;
 250         struct netpoll_info *npinfo;
 251
 252         if (!np || !np->dev || !netif_running(np->dev)) {
 253                 __kfree_skb(skb);
 254                 return;
 255         }
 256
 257         npinfo = np->dev->npinfo;
 258
 259         /* avoid recursion */
 260         if (npinfo->poll_owner == smp_processor_id() ||
 261             np->dev->xmit_lock_owner == smp_processor_id()) {
 262                 if (np->drop)
 263                         np->drop(skb);
 264                 else
 265                         __kfree_skb(skb);
 266                 return;
 267         }
 268
 269         do {
 270                 npinfo->tries--;
 271                 spin_lock(&np->dev->xmit_lock);
 272                 np->dev->xmit_lock_owner = smp_processor_id();
 273
 274                 /*
 275                  * network drivers do not expect to be called if the queue is
 276                  * stopped.
 277                  */
 278                 if (netif_queue_stopped(np->dev)) {
 279                         np->dev->xmit_lock_owner = -1;
 280                         spin_unlock(&np->dev->xmit_lock);
 281                         netpoll_poll(np);
 282                         udelay(50);
 283                         continue;
 284                 }
 285
 286                 status = np->dev->hard_start_xmit(skb, np->dev);
 287                 np->dev->xmit_lock_owner = -1;
 288                 spin_unlock(&np->dev->xmit_lock);
 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         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
 327         iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 328
 329         /* iph->version = 4; iph->ihl = 5; */
 330         put_unaligned(0x45, (unsigned char *)iph);
 331         iph->tos      = 0;
 332         put_unaligned(htons(ip_len), &(iph->tot_len));
 333         iph->id       = 0;
 334         iph->frag_off = 0;
 335         iph->ttl      = 64;
 336         iph->protocol = IPPROTO_UDP;
 337         iph->check    = 0;
 338         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 339         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 340         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 341
 342         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 343
 344         eth->h_proto = htons(ETH_P_IP);
 345         memcpy(eth->h_source, np->local_mac, 6);
 346         memcpy(eth->h_dest, np->remote_mac, 6);
 347
 348         skb->dev = np->dev;
 349
 350         netpoll_send_skb(np, skb);
 351 }
 352
 353 static void arp_reply(struct sk_buff *skb)
 354 {
 355         struct netpoll_info *npinfo = skb->dev->npinfo;
 356         struct arphdr *arp;
 357         unsigned char *arp_ptr;
 358         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 359         u32 sip, tip;
 360         struct sk_buff *send_skb;
 361         struct netpoll *np = NULL;
 362
 363         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 364                 np = npinfo->rx_np;
 365         if (!np)
 366                 return;
 367
 368         /* No arp on this interface */
 369         if (skb->dev->flags & IFF_NOARP)
 370                 return;
 371
 372         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 373                                  (2 * skb->dev->addr_len) +
 374                                  (2 * sizeof(u32)))))
 375                 return;
 376
 377         skb->h.raw = skb->nh.raw = skb->data;
 378         arp = skb->nh.arph;
 379
 380         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 381              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 382             arp->ar_pro != htons(ETH_P_IP) ||
 383             arp->ar_op != htons(ARPOP_REQUEST))
 384                 return;
 385
 386         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
 387         memcpy(&sip, arp_ptr, 4);
 388         arp_ptr += 4 + skb->dev->addr_len;
 389         memcpy(&tip, arp_ptr, 4);
 390
 391         /* Should we ignore arp? */
 392         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 393                 return;
 394
 395         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 396         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 397                             LL_RESERVED_SPACE(np->dev));
 398
 399         if (!send_skb)
 400                 return;
 401
 402         send_skb->nh.raw = send_skb->data;
 403         arp = (struct arphdr *) skb_put(send_skb, size);
 404         send_skb->dev = skb->dev;
 405         send_skb->protocol = htons(ETH_P_ARP);
 406
 407         /* Fill the device header for the ARP frame */
 408
 409         if (np->dev->hard_header &&
 410             np->dev->hard_header(send_skb, skb->dev, ptype,
 411                                        np->remote_mac, np->local_mac,
 412                                        send_skb->len) < 0) {
 413                 kfree_skb(send_skb);
 414                 return;
 415         }
 416
 417         /*
 418          * Fill out the arp protocol part.
 419          *
 420          * we only support ethernet device type,
 421          * which (according to RFC 1390) should always equal 1 (Ethernet).
 422          */
 423
 424         arp->ar_hrd = htons(np->dev->type);
 425         arp->ar_pro = htons(ETH_P_IP);
 426         arp->ar_hln = np->dev->addr_len;
 427         arp->ar_pln = 4;
 428         arp->ar_op = htons(type);
 429
 430         arp_ptr=(unsigned char *)(arp + 1);
 431         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 432         arp_ptr += np->dev->addr_len;
 433         memcpy(arp_ptr, &tip, 4);
 434         arp_ptr += 4;
 435         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
 436         arp_ptr += np->dev->addr_len;
 437         memcpy(arp_ptr, &sip, 4);
 438
 439         netpoll_send_skb(np, send_skb);
 440 }
 441
 442 int __netpoll_rx(struct sk_buff *skb)
 443 {
 444         int proto, len, ulen;
 445         struct iphdr *iph;
 446         struct udphdr *uh;
 447         struct netpoll *np = skb->dev->npinfo->rx_np;
 448
 449         if (!np)
 450                 goto out;
 451         if (skb->dev->type != ARPHRD_ETHER)
 452                 goto out;
 453
 454         /* check if netpoll clients need ARP */
 455         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 456             atomic_read(&trapped)) {
 457                 arp_reply(skb);
 458                 return 1;
 459         }
 460
 461         proto = ntohs(eth_hdr(skb)->h_proto);
 462         if (proto != ETH_P_IP)
 463                 goto out;
 464         if (skb->pkt_type == PACKET_OTHERHOST)
 465                 goto out;
 466         if (skb_shared(skb))
 467                 goto out;
 468
 469         iph = (struct iphdr *)skb->data;
 470         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 471                 goto out;
 472         if (iph->ihl < 5 || iph->version != 4)
 473                 goto out;
 474         if (!pskb_may_pull(skb, iph->ihl*4))
 475                 goto out;
 476         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 477                 goto out;
 478
 479         len = ntohs(iph->tot_len);
 480         if (skb->len < len || len < iph->ihl*4)
 481                 goto out;
 482
 483         if (iph->protocol != IPPROTO_UDP)
 484                 goto out;
 485
 486         len -= iph->ihl*4;
 487         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 488         ulen = ntohs(uh->len);
 489
 490         if (ulen != len)
 491                 goto out;
 492         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr) < 0)
 493                 goto out;
 494         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 495                 goto out;
 496         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 497                 goto out;
 498         if (np->local_port && np->local_port != ntohs(uh->dest))
 499                 goto out;
 500
 501         np->rx_hook(np, ntohs(uh->source),
 502                     (char *)(uh+1),
 503                     ulen - sizeof(struct udphdr));
 504
 505         kfree_skb(skb);
 506         return 1;
 507
 508 out:
 509         if (atomic_read(&trapped)) {
 510                 kfree_skb(skb);
 511                 return 1;
 512         }
 513
 514         return 0;
 515 }
 516
 517 int netpoll_parse_options(struct netpoll *np, char *opt)
 518 {
 519         char *cur=opt, *delim;
 520
 521         if(*cur != '@') {
 522                 if ((delim = strchr(cur, '@')) == NULL)
 523                         goto parse_failed;
 524                 *delim=0;
 525                 np->local_port=simple_strtol(cur, NULL, 10);
 526                 cur=delim;
 527         }
 528         cur++;
 529         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 530
 531         if(*cur != '/') {
 532                 if ((delim = strchr(cur, '/')) == NULL)
 533                         goto parse_failed;
 534                 *delim=0;
 535                 np->local_ip=ntohl(in_aton(cur));
 536                 cur=delim;
 537
 538                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 539                        np->name, HIPQUAD(np->local_ip));
 540         }
 541         cur++;
 542
 543         if ( *cur != ',') {
 544                 /* parse out dev name */
 545                 if ((delim = strchr(cur, ',')) == NULL)
 546                         goto parse_failed;
 547                 *delim=0;
 548                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 549                 cur=delim;
 550         }
 551         cur++;
 552
 553         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 554
 555         if ( *cur != '@' ) {
 556                 /* dst port */
 557                 if ((delim = strchr(cur, '@')) == NULL)
 558                         goto parse_failed;
 559                 *delim=0;
 560                 np->remote_port=simple_strtol(cur, NULL, 10);
 561                 cur=delim;
 562         }
 563         cur++;
 564         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 565
 566         /* dst ip */
 567         if ((delim = strchr(cur, '/')) == NULL)
 568                 goto parse_failed;
 569         *delim=0;
 570         np->remote_ip=ntohl(in_aton(cur));
 571         cur=delim+1;
 572
 573         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 574                        np->name, HIPQUAD(np->remote_ip));
 575
 576         if( *cur != 0 )
 577         {
 578                 /* MAC address */
 579                 if ((delim = strchr(cur, ':')) == NULL)
 580                         goto parse_failed;
 581                 *delim=0;
 582                 np->remote_mac[0]=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[1]=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[2]=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[3]=simple_strtol(cur, NULL, 16);
 598                 cur=delim+1;
 599                 if ((delim = strchr(cur, ':')) == NULL)
 600                         goto parse_failed;
 601                 *delim=0;
 602                 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
 603                 cur=delim+1;
 604                 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
 605         }
 606
 607         printk(KERN_INFO "%s: remote ethernet address "
 608                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 609                np->name,
 610                np->remote_mac[0],
 611                np->remote_mac[1],
 612                np->remote_mac[2],
 613                np->remote_mac[3],
 614                np->remote_mac[4],
 615                np->remote_mac[5]);
 616
 617         return 0;
 618
 619  parse_failed:
 620         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 621                np->name, cur);
 622         return -1;
 623 }
 624
 625 int netpoll_setup(struct netpoll *np)
 626 {
 627         struct net_device *ndev = NULL;
 628         struct in_device *in_dev;
 629         struct netpoll_info *npinfo;
 630         unsigned long flags;
 631
 632         if (np->dev_name)
 633                 ndev = dev_get_by_name(np->dev_name);
 634         if (!ndev) {
 635                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 636                        np->name, np->dev_name);
 637                 return -1;
 638         }
 639
 640         np->dev = ndev;
 641         if (!ndev->npinfo) {
 642                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 643                 if (!npinfo)
 644                         goto release;
 645
 646                 npinfo->rx_flags = 0;
 647                 npinfo->rx_np = NULL;
 648                 spin_lock_init(&npinfo->poll_lock);
 649                 npinfo->poll_owner = -1;
 650                 npinfo->tries = MAX_RETRIES;
 651                 spin_lock_init(&npinfo->rx_lock);
 652         } else
 653                 npinfo = ndev->npinfo;
 654
 655         if (!ndev->poll_controller) {
 656                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 657                        np->name, np->dev_name);
 658                 goto release;
 659         }
 660
 661         if (!netif_running(ndev)) {
 662                 unsigned long atmost, atleast;
 663
 664                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 665                        np->name, np->dev_name);
 666
 667                 rtnl_shlock();
 668                 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
 669                         printk(KERN_ERR "%s: failed to open %s\n",
 670                                np->name, np->dev_name);
 671                         rtnl_shunlock();
 672                         goto release;
 673                 }
 674                 rtnl_shunlock();
 675
 676                 atleast = jiffies + HZ/10;
 677                 atmost = jiffies + 4*HZ;
 678                 while (!netif_carrier_ok(ndev)) {
 679                         if (time_after(jiffies, atmost)) {
 680                                 printk(KERN_NOTICE
 681                                        "%s: timeout waiting for carrier\n",
 682                                        np->name);
 683                                 break;
 684                         }
 685                         cond_resched();
 686                 }
 687
 688                 /* If carrier appears to come up instantly, we don't
 689                  * trust it and pause so that we don't pump all our
 690                  * queued console messages into the bitbucket.
 691                  */
 692
 693                 if (time_before(jiffies, atleast)) {
 694                         printk(KERN_NOTICE "%s: carrier detect appears"
 695                                " untrustworthy, waiting 4 seconds\n",
 696                                np->name);
 697                         msleep(4000);
 698                 }
 699         }
 700
 701         if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
 702                 memcpy(np->local_mac, ndev->dev_addr, 6);
 703
 704         if (!np->local_ip) {
 705                 rcu_read_lock();
 706                 in_dev = __in_dev_get(ndev);
 707
 708                 if (!in_dev || !in_dev->ifa_list) {
 709                         rcu_read_unlock();
 710                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 711                                np->name, np->dev_name);
 712                         goto release;
 713                 }
 714
 715                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 716                 rcu_read_unlock();
 717                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 718                        np->name, HIPQUAD(np->local_ip));
 719         }
 720
 721         if (np->rx_hook) {
 722                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 723                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 724                 npinfo->rx_np = np;
 725                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 726         }
 727
 728         /* fill up the skb queue */
 729         refill_skbs();
 730
 731         /* last thing to do is link it to the net device structure */
 732         ndev->npinfo = npinfo;
 733
 734         /* avoid racing with NAPI reading npinfo */
 735         synchronize_rcu();
 736
 737         return 0;
 738
 739  release:
 740         if (!ndev->npinfo)
 741                 kfree(npinfo);
 742         np->dev = NULL;
 743         dev_put(ndev);
 744         return -1;
 745 }
 746
 747 void netpoll_cleanup(struct netpoll *np)
 748 {
 749         struct netpoll_info *npinfo;
 750         unsigned long flags;
 751
 752         if (np->dev) {
 753                 npinfo = np->dev->npinfo;
 754                 if (npinfo && npinfo->rx_np == np) {
 755                         spin_lock_irqsave(&npinfo->rx_lock, flags);
 756                         npinfo->rx_np = NULL;
 757                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 758                         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 759                 }
 760                 dev_put(np->dev);
 761         }
 762
 763         np->dev = NULL;
 764 }
 765
 766 int netpoll_trap(void)
 767 {
 768         return atomic_read(&trapped);
 769 }
 770
 771 void netpoll_set_trap(int trap)
 772 {
 773         if (trap)
 774                 atomic_inc(&trapped);
 775         else
 776                 atomic_dec(&trapped);
 777 }
 778
 779 EXPORT_SYMBOL(netpoll_set_trap);
 780 EXPORT_SYMBOL(netpoll_trap);
 781 EXPORT_SYMBOL(netpoll_parse_options);
 782 EXPORT_SYMBOL(netpoll_setup);
 783 EXPORT_SYMBOL(netpoll_cleanup);
 784 EXPORT_SYMBOL(netpoll_send_udp);
 785 EXPORT_SYMBOL(netpoll_poll);
 786 EXPORT_SYMBOL(netpoll_queue);