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 DEFINE_SPINLOCK(skb_list_lock);
  40 static int nr_skbs;
  41 static struct sk_buff *skbs;
  42
  43 static DEFINE_SPINLOCK(queue_lock);
  44 static int queue_depth;
  45 static struct sk_buff *queue_head, *queue_tail;
  46
  47 static atomic_t trapped;
  48
  49 #define NETPOLL_RX_ENABLED  1
  50 #define NETPOLL_RX_DROP     2
  51
  52 #define MAX_SKB_SIZE \
  53                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  54                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  55
  56 static void zap_completion_queue(void);
  57 static void arp_reply(struct sk_buff *skb);
  58
  59 static void queue_process(void *p)
  60 {
  61         unsigned long flags;
  62         struct sk_buff *skb;
  63
  64         while (queue_head) {
  65                 spin_lock_irqsave(&queue_lock, flags);
  66
  67                 skb = queue_head;
  68                 queue_head = skb->next;
  69                 if (skb == queue_tail)
  70                         queue_head = NULL;
  71
  72                 queue_depth--;
  73
  74                 spin_unlock_irqrestore(&queue_lock, flags);
  75
  76                 dev_queue_xmit(skb);
  77         }
  78 }
  79
  80 static DECLARE_WORK(send_queue, queue_process, NULL);
  81
  82 void netpoll_queue(struct sk_buff *skb)
  83 {
  84         unsigned long flags;
  85
  86         if (queue_depth == MAX_QUEUE_DEPTH) {
  87                 __kfree_skb(skb);
  88                 return;
  89         }
  90
  91         spin_lock_irqsave(&queue_lock, flags);
  92         if (!queue_head)
  93                 queue_head = skb;
  94         else
  95                 queue_tail->next = skb;
  96         queue_tail = skb;
  97         queue_depth++;
  98         spin_unlock_irqrestore(&queue_lock, flags);
  99
 100         schedule_work(&send_queue);
 101 }
 102
 103 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 104                              unsigned short ulen, u32 saddr, u32 daddr)
 105 {
 106         unsigned int psum;
 107
 108         if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY)
 109                 return 0;
 110
 111         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 112
 113         if (skb->ip_summed == CHECKSUM_HW &&
 114             !(u16)csum_fold(csum_add(psum, skb->csum)))
 115                 return 0;
 116
 117         skb->csum = psum;
 118
 119         return __skb_checksum_complete(skb);
 120 }
 121
 122 /*
 123  * Check whether delayed processing was scheduled for our NIC. If so,
 124  * we attempt to grab the poll lock and use ->poll() to pump the card.
 125  * If this fails, either we've recursed in ->poll() or it's already
 126  * running on another CPU.
 127  *
 128  * Note: we don't mask interrupts with this lock because we're using
 129  * trylock here and interrupts are already disabled in the softirq
 130  * case. Further, we test the poll_owner to avoid recursion on UP
 131  * systems where the lock doesn't exist.
 132  *
 133  * In cases where there is bi-directional communications, reading only
 134  * one message at a time can lead to packets being dropped by the
 135  * network adapter, forcing superfluous retries and possibly timeouts.
 136  * Thus, we set our budget to greater than 1.
 137  */
 138 static void poll_napi(struct netpoll *np)
 139 {
 140         struct netpoll_info *npinfo = np->dev->npinfo;
 141         int budget = 16;
 142
 143         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
 144             npinfo->poll_owner != smp_processor_id() &&
 145             spin_trylock(&npinfo->poll_lock)) {
 146                 npinfo->rx_flags |= NETPOLL_RX_DROP;
 147                 atomic_inc(&trapped);
 148
 149                 np->dev->poll(np->dev, &budget);
 150
 151                 atomic_dec(&trapped);
 152                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 153                 spin_unlock(&npinfo->poll_lock);
 154         }
 155 }
 156
 157 static void service_arp_queue(struct netpoll_info *npi)
 158 {
 159         struct sk_buff *skb;
 160
 161         if (unlikely(!npi))
 162                 return;
 163
 164         skb = skb_dequeue(&npi->arp_tx);
 165
 166         while (skb != NULL) {
 167                 arp_reply(skb);
 168                 skb = skb_dequeue(&npi->arp_tx);
 169         }
 170         return;
 171 }
 172
 173 void netpoll_poll(struct netpoll *np)
 174 {
 175         if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
 176                 return;
 177
 178         /* Process pending work on NIC */
 179         np->dev->poll_controller(np->dev);
 180         if (np->dev->poll)
 181                 poll_napi(np);
 182
 183         service_arp_queue(np->dev->npinfo);
 184
 185         zap_completion_queue();
 186 }
 187
 188 static void refill_skbs(void)
 189 {
 190         struct sk_buff *skb;
 191         unsigned long flags;
 192
 193         spin_lock_irqsave(&skb_list_lock, flags);
 194         while (nr_skbs < MAX_SKBS) {
 195                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 196                 if (!skb)
 197                         break;
 198
 199                 skb->next = skbs;
 200                 skbs = skb;
 201                 nr_skbs++;
 202         }
 203         spin_unlock_irqrestore(&skb_list_lock, flags);
 204 }
 205
 206 static void zap_completion_queue(void)
 207 {
 208         unsigned long flags;
 209         struct softnet_data *sd = &get_cpu_var(softnet_data);
 210
 211         if (sd->completion_queue) {
 212                 struct sk_buff *clist;
 213
 214                 local_irq_save(flags);
 215                 clist = sd->completion_queue;
 216                 sd->completion_queue = NULL;
 217                 local_irq_restore(flags);
 218
 219                 while (clist != NULL) {
 220                         struct sk_buff *skb = clist;
 221                         clist = clist->next;
 222                         if(skb->destructor)
 223                                 dev_kfree_skb_any(skb); /* put this one back */
 224                         else
 225                                 __kfree_skb(skb);
 226                 }
 227         }
 228
 229         put_cpu_var(softnet_data);
 230 }
 231
 232 static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
 233 {
 234         int once = 1, count = 0;
 235         unsigned long flags;
 236         struct sk_buff *skb = NULL;
 237
 238         zap_completion_queue();
 239 repeat:
 240         if (nr_skbs < MAX_SKBS)
 241                 refill_skbs();
 242
 243         skb = alloc_skb(len, GFP_ATOMIC);
 244
 245         if (!skb) {
 246                 spin_lock_irqsave(&skb_list_lock, flags);
 247                 skb = skbs;
 248                 if (skb) {
 249                         skbs = skb->next;
 250                         skb->next = NULL;
 251                         nr_skbs--;
 252                 }
 253                 spin_unlock_irqrestore(&skb_list_lock, flags);
 254         }
 255
 256         if(!skb) {
 257                 count++;
 258                 if (once && (count == 1000000)) {
 259                         printk("out of netpoll skbs!\n");
 260                         once = 0;
 261                 }
 262                 netpoll_poll(np);
 263                 goto repeat;
 264         }
 265
 266         atomic_set(&skb->users, 1);
 267         skb_reserve(skb, reserve);
 268         return skb;
 269 }
 270
 271 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 272 {
 273         int status;
 274         struct netpoll_info *npinfo;
 275
 276         if (!np || !np->dev || !netif_running(np->dev))
 277                 goto free_skb;
 278
 279         npinfo = np->dev->npinfo;
 280
 281         /* avoid recursion */
 282         if (npinfo->poll_owner == smp_processor_id() ||
 283             np->dev->xmit_lock_owner == smp_processor_id()) {
 284                 if (np->drop)
 285                         np->drop(skb);
 286                 else
 287                         __kfree_skb(skb);
 288                 return;
 289         }
 290
 291         do {
 292                 npinfo->tries--;
 293                 netif_tx_lock(np->dev);
 294
 295                 /*
 296                  * network drivers do not expect to be called if the queue is
 297                  * stopped.
 298                  */
 299                 status = NETDEV_TX_BUSY;
 300                 if (!netif_queue_stopped(np->dev))
 301                         status = np->dev->hard_start_xmit(skb, np->dev);
 302
 303                 netif_tx_unlock(np->dev);
 304
 305                 /* success */
 306                 if(!status) {
 307                         npinfo->tries = MAX_RETRIES; /* reset */
 308                         return;
 309                 }
 310
 311                 /* transmit busy */
 312                 netpoll_poll(np);
 313                 udelay(50);
 314         } while (npinfo->tries > 0);
 315 free_skb:
 316         __kfree_skb(skb);
 317 }
 318
 319 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 320 {
 321         int total_len, eth_len, ip_len, udp_len;
 322         struct sk_buff *skb;
 323         struct udphdr *udph;
 324         struct iphdr *iph;
 325         struct ethhdr *eth;
 326
 327         udp_len = len + sizeof(*udph);
 328         ip_len = eth_len = udp_len + sizeof(*iph);
 329         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 330
 331         skb = find_skb(np, total_len, total_len - len);
 332         if (!skb)
 333                 return;
 334
 335         memcpy(skb->data, msg, len);
 336         skb->len += len;
 337
 338         skb->h.uh = udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 339         udph->source = htons(np->local_port);
 340         udph->dest = htons(np->remote_port);
 341         udph->len = htons(udp_len);
 342         udph->check = 0;
 343
 344         skb->nh.iph = iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 345
 346         /* iph->version = 4; iph->ihl = 5; */
 347         put_unaligned(0x45, (unsigned char *)iph);
 348         iph->tos      = 0;
 349         put_unaligned(htons(ip_len), &(iph->tot_len));
 350         iph->id       = 0;
 351         iph->frag_off = 0;
 352         iph->ttl      = 64;
 353         iph->protocol = IPPROTO_UDP;
 354         iph->check    = 0;
 355         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 356         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 357         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 358
 359         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 360         skb->mac.raw = skb->data;
 361         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 362         memcpy(eth->h_source, np->local_mac, 6);
 363         memcpy(eth->h_dest, np->remote_mac, 6);
 364
 365         skb->dev = np->dev;
 366
 367         netpoll_send_skb(np, skb);
 368 }
 369
 370 static void arp_reply(struct sk_buff *skb)
 371 {
 372         struct netpoll_info *npinfo = skb->dev->npinfo;
 373         struct arphdr *arp;
 374         unsigned char *arp_ptr;
 375         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 376         u32 sip, tip;
 377         struct sk_buff *send_skb;
 378         struct netpoll *np = NULL;
 379
 380         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 381                 np = npinfo->rx_np;
 382         if (!np)
 383                 return;
 384
 385         /* No arp on this interface */
 386         if (skb->dev->flags & IFF_NOARP)
 387                 return;
 388
 389         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 390                                  (2 * skb->dev->addr_len) +
 391                                  (2 * sizeof(u32)))))
 392                 return;
 393
 394         skb->h.raw = skb->nh.raw = skb->data;
 395         arp = skb->nh.arph;
 396
 397         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 398              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 399             arp->ar_pro != htons(ETH_P_IP) ||
 400             arp->ar_op != htons(ARPOP_REQUEST))
 401                 return;
 402
 403         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
 404         memcpy(&sip, arp_ptr, 4);
 405         arp_ptr += 4 + skb->dev->addr_len;
 406         memcpy(&tip, arp_ptr, 4);
 407
 408         /* Should we ignore arp? */
 409         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 410                 return;
 411
 412         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 413         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 414                             LL_RESERVED_SPACE(np->dev));
 415
 416         if (!send_skb)
 417                 return;
 418
 419         send_skb->nh.raw = send_skb->data;
 420         arp = (struct arphdr *) skb_put(send_skb, size);
 421         send_skb->dev = skb->dev;
 422         send_skb->protocol = htons(ETH_P_ARP);
 423
 424         /* Fill the device header for the ARP frame */
 425
 426         if (np->dev->hard_header &&
 427             np->dev->hard_header(send_skb, skb->dev, ptype,
 428                                        np->remote_mac, np->local_mac,
 429                                        send_skb->len) < 0) {
 430                 kfree_skb(send_skb);
 431                 return;
 432         }
 433
 434         /*
 435          * Fill out the arp protocol part.
 436          *
 437          * we only support ethernet device type,
 438          * which (according to RFC 1390) should always equal 1 (Ethernet).
 439          */
 440
 441         arp->ar_hrd = htons(np->dev->type);
 442         arp->ar_pro = htons(ETH_P_IP);
 443         arp->ar_hln = np->dev->addr_len;
 444         arp->ar_pln = 4;
 445         arp->ar_op = htons(type);
 446
 447         arp_ptr=(unsigned char *)(arp + 1);
 448         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 449         arp_ptr += np->dev->addr_len;
 450         memcpy(arp_ptr, &tip, 4);
 451         arp_ptr += 4;
 452         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
 453         arp_ptr += np->dev->addr_len;
 454         memcpy(arp_ptr, &sip, 4);
 455
 456         netpoll_send_skb(np, send_skb);
 457 }
 458
 459 int __netpoll_rx(struct sk_buff *skb)
 460 {
 461         int proto, len, ulen;
 462         struct iphdr *iph;
 463         struct udphdr *uh;
 464         struct netpoll_info *npi = skb->dev->npinfo;
 465         struct netpoll *np = npi->rx_np;
 466
 467
 468         if (!np)
 469                 goto out;
 470         if (skb->dev->type != ARPHRD_ETHER)
 471                 goto out;
 472
 473         /* check if netpoll clients need ARP */
 474         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 475             atomic_read(&trapped)) {
 476                 skb_queue_tail(&npi->arp_tx, skb);
 477                 return 1;
 478         }
 479
 480         proto = ntohs(eth_hdr(skb)->h_proto);
 481         if (proto != ETH_P_IP)
 482                 goto out;
 483         if (skb->pkt_type == PACKET_OTHERHOST)
 484                 goto out;
 485         if (skb_shared(skb))
 486                 goto out;
 487
 488         iph = (struct iphdr *)skb->data;
 489         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 490                 goto out;
 491         if (iph->ihl < 5 || iph->version != 4)
 492                 goto out;
 493         if (!pskb_may_pull(skb, iph->ihl*4))
 494                 goto out;
 495         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 496                 goto out;
 497
 498         len = ntohs(iph->tot_len);
 499         if (skb->len < len || len < iph->ihl*4)
 500                 goto out;
 501
 502         if (iph->protocol != IPPROTO_UDP)
 503                 goto out;
 504
 505         len -= iph->ihl*4;
 506         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 507         ulen = ntohs(uh->len);
 508
 509         if (ulen != len)
 510                 goto out;
 511         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 512                 goto out;
 513         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 514                 goto out;
 515         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 516                 goto out;
 517         if (np->local_port && np->local_port != ntohs(uh->dest))
 518                 goto out;
 519
 520         np->rx_hook(np, ntohs(uh->source),
 521                     (char *)(uh+1),
 522                     ulen - sizeof(struct udphdr));
 523
 524         kfree_skb(skb);
 525         return 1;
 526
 527 out:
 528         if (atomic_read(&trapped)) {
 529                 kfree_skb(skb);
 530                 return 1;
 531         }
 532
 533         return 0;
 534 }
 535
 536 int netpoll_parse_options(struct netpoll *np, char *opt)
 537 {
 538         char *cur=opt, *delim;
 539
 540         if(*cur != '@') {
 541                 if ((delim = strchr(cur, '@')) == NULL)
 542                         goto parse_failed;
 543                 *delim=0;
 544                 np->local_port=simple_strtol(cur, NULL, 10);
 545                 cur=delim;
 546         }
 547         cur++;
 548         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 549
 550         if(*cur != '/') {
 551                 if ((delim = strchr(cur, '/')) == NULL)
 552                         goto parse_failed;
 553                 *delim=0;
 554                 np->local_ip=ntohl(in_aton(cur));
 555                 cur=delim;
 556
 557                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 558                        np->name, HIPQUAD(np->local_ip));
 559         }
 560         cur++;
 561
 562         if ( *cur != ',') {
 563                 /* parse out dev name */
 564                 if ((delim = strchr(cur, ',')) == NULL)
 565                         goto parse_failed;
 566                 *delim=0;
 567                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 568                 cur=delim;
 569         }
 570         cur++;
 571
 572         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 573
 574         if ( *cur != '@' ) {
 575                 /* dst port */
 576                 if ((delim = strchr(cur, '@')) == NULL)
 577                         goto parse_failed;
 578                 *delim=0;
 579                 np->remote_port=simple_strtol(cur, NULL, 10);
 580                 cur=delim;
 581         }
 582         cur++;
 583         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 584
 585         /* dst ip */
 586         if ((delim = strchr(cur, '/')) == NULL)
 587                 goto parse_failed;
 588         *delim=0;
 589         np->remote_ip=ntohl(in_aton(cur));
 590         cur=delim+1;
 591
 592         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 593                        np->name, HIPQUAD(np->remote_ip));
 594
 595         if( *cur != 0 )
 596         {
 597                 /* MAC address */
 598                 if ((delim = strchr(cur, ':')) == NULL)
 599                         goto parse_failed;
 600                 *delim=0;
 601                 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
 602                 cur=delim+1;
 603                 if ((delim = strchr(cur, ':')) == NULL)
 604                         goto parse_failed;
 605                 *delim=0;
 606                 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
 607                 cur=delim+1;
 608                 if ((delim = strchr(cur, ':')) == NULL)
 609                         goto parse_failed;
 610                 *delim=0;
 611                 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
 612                 cur=delim+1;
 613                 if ((delim = strchr(cur, ':')) == NULL)
 614                         goto parse_failed;
 615                 *delim=0;
 616                 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
 617                 cur=delim+1;
 618                 if ((delim = strchr(cur, ':')) == NULL)
 619                         goto parse_failed;
 620                 *delim=0;
 621                 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
 622                 cur=delim+1;
 623                 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
 624         }
 625
 626         printk(KERN_INFO "%s: remote ethernet address "
 627                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 628                np->name,
 629                np->remote_mac[0],
 630                np->remote_mac[1],
 631                np->remote_mac[2],
 632                np->remote_mac[3],
 633                np->remote_mac[4],
 634                np->remote_mac[5]);
 635
 636         return 0;
 637
 638  parse_failed:
 639         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 640                np->name, cur);
 641         return -1;
 642 }
 643
 644 int netpoll_setup(struct netpoll *np)
 645 {
 646         struct net_device *ndev = NULL;
 647         struct in_device *in_dev;
 648         struct netpoll_info *npinfo;
 649         unsigned long flags;
 650
 651         if (np->dev_name)
 652                 ndev = dev_get_by_name(np->dev_name);
 653         if (!ndev) {
 654                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 655                        np->name, np->dev_name);
 656                 return -1;
 657         }
 658
 659         np->dev = ndev;
 660         if (!ndev->npinfo) {
 661                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 662                 if (!npinfo)
 663                         goto release;
 664
 665                 npinfo->rx_flags = 0;
 666                 npinfo->rx_np = NULL;
 667                 spin_lock_init(&npinfo->poll_lock);
 668                 npinfo->poll_owner = -1;
 669                 npinfo->tries = MAX_RETRIES;
 670                 spin_lock_init(&npinfo->rx_lock);
 671                 skb_queue_head_init(&npinfo->arp_tx);
 672         } else
 673                 npinfo = ndev->npinfo;
 674
 675         if (!ndev->poll_controller) {
 676                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 677                        np->name, np->dev_name);
 678                 goto release;
 679         }
 680
 681         if (!netif_running(ndev)) {
 682                 unsigned long atmost, atleast;
 683
 684                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 685                        np->name, np->dev_name);
 686
 687                 rtnl_lock();
 688                 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
 689                         printk(KERN_ERR "%s: failed to open %s\n",
 690                                np->name, np->dev_name);
 691                         rtnl_unlock();
 692                         goto release;
 693                 }
 694                 rtnl_unlock();
 695
 696                 atleast = jiffies + HZ/10;
 697                 atmost = jiffies + 4*HZ;
 698                 while (!netif_carrier_ok(ndev)) {
 699                         if (time_after(jiffies, atmost)) {
 700                                 printk(KERN_NOTICE
 701                                        "%s: timeout waiting for carrier\n",
 702                                        np->name);
 703                                 break;
 704                         }
 705                         cond_resched();
 706                 }
 707
 708                 /* If carrier appears to come up instantly, we don't
 709                  * trust it and pause so that we don't pump all our
 710                  * queued console messages into the bitbucket.
 711                  */
 712
 713                 if (time_before(jiffies, atleast)) {
 714                         printk(KERN_NOTICE "%s: carrier detect appears"
 715                                " untrustworthy, waiting 4 seconds\n",
 716                                np->name);
 717                         msleep(4000);
 718                 }
 719         }
 720
 721         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
 722                 memcpy(np->local_mac, ndev->dev_addr, 6);
 723
 724         if (!np->local_ip) {
 725                 rcu_read_lock();
 726                 in_dev = __in_dev_get_rcu(ndev);
 727
 728                 if (!in_dev || !in_dev->ifa_list) {
 729                         rcu_read_unlock();
 730                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 731                                np->name, np->dev_name);
 732                         goto release;
 733                 }
 734
 735                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 736                 rcu_read_unlock();
 737                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 738                        np->name, HIPQUAD(np->local_ip));
 739         }
 740
 741         if (np->rx_hook) {
 742                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 743                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 744                 npinfo->rx_np = np;
 745                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 746         }
 747
 748         /* fill up the skb queue */
 749         refill_skbs();
 750
 751         /* last thing to do is link it to the net device structure */
 752         ndev->npinfo = npinfo;
 753
 754         /* avoid racing with NAPI reading npinfo */
 755         synchronize_rcu();
 756
 757         return 0;
 758
 759  release:
 760         if (!ndev->npinfo)
 761                 kfree(npinfo);
 762         np->dev = NULL;
 763         dev_put(ndev);
 764         return -1;
 765 }
 766
 767 void netpoll_cleanup(struct netpoll *np)
 768 {
 769         struct netpoll_info *npinfo;
 770         unsigned long flags;
 771
 772         if (np->dev) {
 773                 npinfo = np->dev->npinfo;
 774                 if (npinfo && npinfo->rx_np == np) {
 775                         spin_lock_irqsave(&npinfo->rx_lock, flags);
 776                         npinfo->rx_np = NULL;
 777                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 778                         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 779                 }
 780                 dev_put(np->dev);
 781         }
 782
 783         np->dev = NULL;
 784 }
 785
 786 int netpoll_trap(void)
 787 {
 788         return atomic_read(&trapped);
 789 }
 790
 791 void netpoll_set_trap(int trap)
 792 {
 793         if (trap)
 794                 atomic_inc(&trapped);
 795         else
 796                 atomic_dec(&trapped);
 797 }
 798
 799 EXPORT_SYMBOL(netpoll_set_trap);
 800 EXPORT_SYMBOL(netpoll_trap);
 801 EXPORT_SYMBOL(netpoll_parse_options);
 802 EXPORT_SYMBOL(netpoll_setup);
 803 EXPORT_SYMBOL(netpoll_cleanup);
 804 EXPORT_SYMBOL(netpoll_send_udp);
 805 EXPORT_SYMBOL(netpoll_poll);
 806 EXPORT_SYMBOL(netpoll_queue);