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
  38 static struct sk_buff_head skb_pool;
  39
  40 static atomic_t trapped;
  41
  42 #define USEC_PER_POLL   50
  43 #define NETPOLL_RX_ENABLED  1
  44 #define NETPOLL_RX_DROP     2
  45
  46 #define MAX_SKB_SIZE \
  47                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  48                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  49
  50 static void zap_completion_queue(void);
  51 static void arp_reply(struct sk_buff *skb);
  52
  53 static void queue_process(struct work_struct *work)
  54 {
  55         struct netpoll_info *npinfo =
  56                 container_of(work, struct netpoll_info, tx_work.work);
  57         struct sk_buff *skb;
  58
  59         while ((skb = skb_dequeue(&npinfo->txq))) {
  60                 struct net_device *dev = skb->dev;
  61
  62                 if (!netif_device_present(dev) || !netif_running(dev)) {
  63                         __kfree_skb(skb);
  64                         continue;
  65                 }
  66
  67                 netif_tx_lock_bh(dev);
  68                 if (netif_queue_stopped(dev) ||
  69                     dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
  70                         skb_queue_head(&npinfo->txq, skb);
  71                         netif_tx_unlock_bh(dev);
  72
  73                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  74                         return;
  75                 }
  76         }
  77 }
  78
  79 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  80                             unsigned short ulen, __be32 saddr, __be32 daddr)
  81 {
  82         __wsum psum;
  83
  84         if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY)
  85                 return 0;
  86
  87         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
  88
  89         if (skb->ip_summed == CHECKSUM_COMPLETE &&
  90             !csum_fold(csum_add(psum, skb->csum)))
  91                 return 0;
  92
  93         skb->csum = psum;
  94
  95         return __skb_checksum_complete(skb);
  96 }
  97
  98 /*
  99  * Check whether delayed processing was scheduled for our NIC. If so,
 100  * we attempt to grab the poll lock and use ->poll() to pump the card.
 101  * If this fails, either we've recursed in ->poll() or it's already
 102  * running on another CPU.
 103  *
 104  * Note: we don't mask interrupts with this lock because we're using
 105  * trylock here and interrupts are already disabled in the softirq
 106  * case. Further, we test the poll_owner to avoid recursion on UP
 107  * systems where the lock doesn't exist.
 108  *
 109  * In cases where there is bi-directional communications, reading only
 110  * one message at a time can lead to packets being dropped by the
 111  * network adapter, forcing superfluous retries and possibly timeouts.
 112  * Thus, we set our budget to greater than 1.
 113  */
 114 static void poll_napi(struct netpoll *np)
 115 {
 116         struct netpoll_info *npinfo = np->dev->npinfo;
 117         int budget = 16;
 118
 119         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
 120             npinfo->poll_owner != smp_processor_id() &&
 121             spin_trylock(&npinfo->poll_lock)) {
 122                 npinfo->rx_flags |= NETPOLL_RX_DROP;
 123                 atomic_inc(&trapped);
 124
 125                 np->dev->poll(np->dev, &budget);
 126
 127                 atomic_dec(&trapped);
 128                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 129                 spin_unlock(&npinfo->poll_lock);
 130         }
 131 }
 132
 133 static void service_arp_queue(struct netpoll_info *npi)
 134 {
 135         struct sk_buff *skb;
 136
 137         if (unlikely(!npi))
 138                 return;
 139
 140         skb = skb_dequeue(&npi->arp_tx);
 141
 142         while (skb != NULL) {
 143                 arp_reply(skb);
 144                 skb = skb_dequeue(&npi->arp_tx);
 145         }
 146 }
 147
 148 void netpoll_poll(struct netpoll *np)
 149 {
 150         if (!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
 151                 return;
 152
 153         /* Process pending work on NIC */
 154         np->dev->poll_controller(np->dev);
 155         if (np->dev->poll)
 156                 poll_napi(np);
 157
 158         service_arp_queue(np->dev->npinfo);
 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_pool.lock, flags);
 169         while (skb_pool.qlen < MAX_SKBS) {
 170                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 171                 if (!skb)
 172                         break;
 173
 174                 __skb_queue_tail(&skb_pool, skb);
 175         }
 176         spin_unlock_irqrestore(&skb_pool.lock, flags);
 177 }
 178
 179 static void zap_completion_queue(void)
 180 {
 181         unsigned long flags;
 182         struct softnet_data *sd = &get_cpu_var(softnet_data);
 183
 184         if (sd->completion_queue) {
 185                 struct sk_buff *clist;
 186
 187                 local_irq_save(flags);
 188                 clist = sd->completion_queue;
 189                 sd->completion_queue = NULL;
 190                 local_irq_restore(flags);
 191
 192                 while (clist != NULL) {
 193                         struct sk_buff *skb = clist;
 194                         clist = clist->next;
 195                         if (skb->destructor)
 196                                 dev_kfree_skb_any(skb); /* put this one back */
 197                         else
 198                                 __kfree_skb(skb);
 199                 }
 200         }
 201
 202         put_cpu_var(softnet_data);
 203 }
 204
 205 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 206 {
 207         int count = 0;
 208         struct sk_buff *skb;
 209
 210         zap_completion_queue();
 211         refill_skbs();
 212 repeat:
 213
 214         skb = alloc_skb(len, GFP_ATOMIC);
 215         if (!skb)
 216                 skb = skb_dequeue(&skb_pool);
 217
 218         if (!skb) {
 219                 if (++count < 10) {
 220                         netpoll_poll(np);
 221                         goto repeat;
 222                 }
 223                 return NULL;
 224         }
 225
 226         atomic_set(&skb->users, 1);
 227         skb_reserve(skb, reserve);
 228         return skb;
 229 }
 230
 231 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 232 {
 233         int status = NETDEV_TX_BUSY;
 234         unsigned long tries;
 235         struct net_device *dev = np->dev;
 236         struct netpoll_info *npinfo = np->dev->npinfo;
 237
 238         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 239                 __kfree_skb(skb);
 240                 return;
 241         }
 242
 243         /* don't get messages out of order, and no recursion */
 244         if (skb_queue_len(&npinfo->txq) == 0 &&
 245             npinfo->poll_owner != smp_processor_id() &&
 246             netif_tx_trylock(dev)) {
 247                 /* try until next clock tick */
 248                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL; tries > 0; --tries) {
 249                         if (!netif_queue_stopped(dev))
 250                                 status = dev->hard_start_xmit(skb, dev);
 251
 252                         if (status == NETDEV_TX_OK)
 253                                 break;
 254
 255                         /* tickle device maybe there is some cleanup */
 256                         netpoll_poll(np);
 257
 258                         udelay(USEC_PER_POLL);
 259                 }
 260                 netif_tx_unlock(dev);
 261         }
 262
 263         if (status != NETDEV_TX_OK) {
 264                 skb_queue_tail(&npinfo->txq, skb);
 265                 schedule_delayed_work(&npinfo->tx_work,0);
 266         }
 267 }
 268
 269 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 270 {
 271         int total_len, eth_len, ip_len, udp_len;
 272         struct sk_buff *skb;
 273         struct udphdr *udph;
 274         struct iphdr *iph;
 275         struct ethhdr *eth;
 276
 277         udp_len = len + sizeof(*udph);
 278         ip_len = eth_len = udp_len + sizeof(*iph);
 279         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 280
 281         skb = find_skb(np, total_len, total_len - len);
 282         if (!skb)
 283                 return;
 284
 285         memcpy(skb->data, msg, len);
 286         skb->len += len;
 287
 288         skb->h.uh = udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 289         udph->source = htons(np->local_port);
 290         udph->dest = htons(np->remote_port);
 291         udph->len = htons(udp_len);
 292         udph->check = 0;
 293         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
 294                                         htonl(np->remote_ip),
 295                                         udp_len, IPPROTO_UDP,
 296                                         csum_partial((unsigned char *)udph, udp_len, 0));
 297         if (udph->check == 0)
 298                 udph->check = CSUM_MANGLED_0;
 299
 300         skb->nh.iph = iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 301
 302         /* iph->version = 4; iph->ihl = 5; */
 303         put_unaligned(0x45, (unsigned char *)iph);
 304         iph->tos      = 0;
 305         put_unaligned(htons(ip_len), &(iph->tot_len));
 306         iph->id       = 0;
 307         iph->frag_off = 0;
 308         iph->ttl      = 64;
 309         iph->protocol = IPPROTO_UDP;
 310         iph->check    = 0;
 311         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 312         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 313         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 314
 315         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 316         skb->mac.raw = skb->data;
 317         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 318         memcpy(eth->h_source, np->local_mac, 6);
 319         memcpy(eth->h_dest, np->remote_mac, 6);
 320
 321         skb->dev = np->dev;
 322
 323         netpoll_send_skb(np, skb);
 324 }
 325
 326 static void arp_reply(struct sk_buff *skb)
 327 {
 328         struct netpoll_info *npinfo = skb->dev->npinfo;
 329         struct arphdr *arp;
 330         unsigned char *arp_ptr;
 331         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 332         __be32 sip, tip;
 333         struct sk_buff *send_skb;
 334         struct netpoll *np = NULL;
 335
 336         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 337                 np = npinfo->rx_np;
 338         if (!np)
 339                 return;
 340
 341         /* No arp on this interface */
 342         if (skb->dev->flags & IFF_NOARP)
 343                 return;
 344
 345         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 346                                  (2 * skb->dev->addr_len) +
 347                                  (2 * sizeof(u32)))))
 348                 return;
 349
 350         skb->h.raw = skb->nh.raw = skb->data;
 351         arp = skb->nh.arph;
 352
 353         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 354              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 355             arp->ar_pro != htons(ETH_P_IP) ||
 356             arp->ar_op != htons(ARPOP_REQUEST))
 357                 return;
 358
 359         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
 360         memcpy(&sip, arp_ptr, 4);
 361         arp_ptr += 4 + skb->dev->addr_len;
 362         memcpy(&tip, arp_ptr, 4);
 363
 364         /* Should we ignore arp? */
 365         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 366                 return;
 367
 368         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 369         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 370                             LL_RESERVED_SPACE(np->dev));
 371
 372         if (!send_skb)
 373                 return;
 374
 375         send_skb->nh.raw = send_skb->data;
 376         arp = (struct arphdr *) skb_put(send_skb, size);
 377         send_skb->dev = skb->dev;
 378         send_skb->protocol = htons(ETH_P_ARP);
 379
 380         /* Fill the device header for the ARP frame */
 381
 382         if (np->dev->hard_header &&
 383             np->dev->hard_header(send_skb, skb->dev, ptype,
 384                                  np->remote_mac, np->local_mac,
 385                                  send_skb->len) < 0) {
 386                 kfree_skb(send_skb);
 387                 return;
 388         }
 389
 390         /*
 391          * Fill out the arp protocol part.
 392          *
 393          * we only support ethernet device type,
 394          * which (according to RFC 1390) should always equal 1 (Ethernet).
 395          */
 396
 397         arp->ar_hrd = htons(np->dev->type);
 398         arp->ar_pro = htons(ETH_P_IP);
 399         arp->ar_hln = np->dev->addr_len;
 400         arp->ar_pln = 4;
 401         arp->ar_op = htons(type);
 402
 403         arp_ptr=(unsigned char *)(arp + 1);
 404         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 405         arp_ptr += np->dev->addr_len;
 406         memcpy(arp_ptr, &tip, 4);
 407         arp_ptr += 4;
 408         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
 409         arp_ptr += np->dev->addr_len;
 410         memcpy(arp_ptr, &sip, 4);
 411
 412         netpoll_send_skb(np, send_skb);
 413 }
 414
 415 int __netpoll_rx(struct sk_buff *skb)
 416 {
 417         int proto, len, ulen;
 418         struct iphdr *iph;
 419         struct udphdr *uh;
 420         struct netpoll_info *npi = skb->dev->npinfo;
 421         struct netpoll *np = npi->rx_np;
 422
 423         if (!np)
 424                 goto out;
 425         if (skb->dev->type != ARPHRD_ETHER)
 426                 goto out;
 427
 428         /* check if netpoll clients need ARP */
 429         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 430             atomic_read(&trapped)) {
 431                 skb_queue_tail(&npi->arp_tx, skb);
 432                 return 1;
 433         }
 434
 435         proto = ntohs(eth_hdr(skb)->h_proto);
 436         if (proto != ETH_P_IP)
 437                 goto out;
 438         if (skb->pkt_type == PACKET_OTHERHOST)
 439                 goto out;
 440         if (skb_shared(skb))
 441                 goto out;
 442
 443         iph = (struct iphdr *)skb->data;
 444         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 445                 goto out;
 446         if (iph->ihl < 5 || iph->version != 4)
 447                 goto out;
 448         if (!pskb_may_pull(skb, iph->ihl*4))
 449                 goto out;
 450         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 451                 goto out;
 452
 453         len = ntohs(iph->tot_len);
 454         if (skb->len < len || len < iph->ihl*4)
 455                 goto out;
 456
 457         if (iph->protocol != IPPROTO_UDP)
 458                 goto out;
 459
 460         len -= iph->ihl*4;
 461         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 462         ulen = ntohs(uh->len);
 463
 464         if (ulen != len)
 465                 goto out;
 466         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 467                 goto out;
 468         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 469                 goto out;
 470         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 471                 goto out;
 472         if (np->local_port && np->local_port != ntohs(uh->dest))
 473                 goto out;
 474
 475         np->rx_hook(np, ntohs(uh->source),
 476                     (char *)(uh+1),
 477                     ulen - sizeof(struct udphdr));
 478
 479         kfree_skb(skb);
 480         return 1;
 481
 482 out:
 483         if (atomic_read(&trapped)) {
 484                 kfree_skb(skb);
 485                 return 1;
 486         }
 487
 488         return 0;
 489 }
 490
 491 int netpoll_parse_options(struct netpoll *np, char *opt)
 492 {
 493         char *cur=opt, *delim;
 494
 495         if (*cur != '@') {
 496                 if ((delim = strchr(cur, '@')) == NULL)
 497                         goto parse_failed;
 498                 *delim = 0;
 499                 np->local_port = simple_strtol(cur, NULL, 10);
 500                 cur = delim;
 501         }
 502         cur++;
 503         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 504
 505         if (*cur != '/') {
 506                 if ((delim = strchr(cur, '/')) == NULL)
 507                         goto parse_failed;
 508                 *delim = 0;
 509                 np->local_ip = ntohl(in_aton(cur));
 510                 cur = delim;
 511
 512                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 513                        np->name, HIPQUAD(np->local_ip));
 514         }
 515         cur++;
 516
 517         if (*cur != ',') {
 518                 /* parse out dev name */
 519                 if ((delim = strchr(cur, ',')) == NULL)
 520                         goto parse_failed;
 521                 *delim = 0;
 522                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 523                 cur = delim;
 524         }
 525         cur++;
 526
 527         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 528
 529         if (*cur != '@') {
 530                 /* dst port */
 531                 if ((delim = strchr(cur, '@')) == NULL)
 532                         goto parse_failed;
 533                 *delim = 0;
 534                 np->remote_port = simple_strtol(cur, NULL, 10);
 535                 cur = delim;
 536         }
 537         cur++;
 538         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 539
 540         /* dst ip */
 541         if ((delim = strchr(cur, '/')) == NULL)
 542                 goto parse_failed;
 543         *delim = 0;
 544         np->remote_ip = ntohl(in_aton(cur));
 545         cur = delim + 1;
 546
 547         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 548                np->name, HIPQUAD(np->remote_ip));
 549
 550         if (*cur != 0) {
 551                 /* MAC address */
 552                 if ((delim = strchr(cur, ':')) == NULL)
 553                         goto parse_failed;
 554                 *delim = 0;
 555                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 556                 cur = delim + 1;
 557                 if ((delim = strchr(cur, ':')) == NULL)
 558                         goto parse_failed;
 559                 *delim = 0;
 560                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 561                 cur = delim + 1;
 562                 if ((delim = strchr(cur, ':')) == NULL)
 563                         goto parse_failed;
 564                 *delim = 0;
 565                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 566                 cur = delim + 1;
 567                 if ((delim = strchr(cur, ':')) == NULL)
 568                         goto parse_failed;
 569                 *delim = 0;
 570                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 571                 cur = delim + 1;
 572                 if ((delim = strchr(cur, ':')) == NULL)
 573                         goto parse_failed;
 574                 *delim = 0;
 575                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 576                 cur = delim + 1;
 577                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 578         }
 579
 580         printk(KERN_INFO "%s: remote ethernet address "
 581                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 582                np->name,
 583                np->remote_mac[0],
 584                np->remote_mac[1],
 585                np->remote_mac[2],
 586                np->remote_mac[3],
 587                np->remote_mac[4],
 588                np->remote_mac[5]);
 589
 590         return 0;
 591
 592  parse_failed:
 593         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 594                np->name, cur);
 595         return -1;
 596 }
 597
 598 int netpoll_setup(struct netpoll *np)
 599 {
 600         struct net_device *ndev = NULL;
 601         struct in_device *in_dev;
 602         struct netpoll_info *npinfo;
 603         unsigned long flags;
 604         int err;
 605
 606         if (np->dev_name)
 607                 ndev = dev_get_by_name(np->dev_name);
 608         if (!ndev) {
 609                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 610                        np->name, np->dev_name);
 611                 return -ENODEV;
 612         }
 613
 614         np->dev = ndev;
 615         if (!ndev->npinfo) {
 616                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 617                 if (!npinfo) {
 618                         err = -ENOMEM;
 619                         goto release;
 620                 }
 621
 622                 npinfo->rx_flags = 0;
 623                 npinfo->rx_np = NULL;
 624                 spin_lock_init(&npinfo->poll_lock);
 625                 npinfo->poll_owner = -1;
 626
 627                 spin_lock_init(&npinfo->rx_lock);
 628                 skb_queue_head_init(&npinfo->arp_tx);
 629                 skb_queue_head_init(&npinfo->txq);
 630                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 631
 632                 atomic_set(&npinfo->refcnt, 1);
 633         } else {
 634                 npinfo = ndev->npinfo;
 635                 atomic_inc(&npinfo->refcnt);
 636         }
 637
 638         if (!ndev->poll_controller) {
 639                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 640                        np->name, np->dev_name);
 641                 err = -ENOTSUPP;
 642                 goto release;
 643         }
 644
 645         if (!netif_running(ndev)) {
 646                 unsigned long atmost, atleast;
 647
 648                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 649                        np->name, np->dev_name);
 650
 651                 rtnl_lock();
 652                 err = dev_open(ndev);
 653                 rtnl_unlock();
 654
 655                 if (err) {
 656                         printk(KERN_ERR "%s: failed to open %s\n",
 657                                np->name, ndev->name);
 658                         goto release;
 659                 }
 660
 661                 atleast = jiffies + HZ/10;
 662                 atmost = jiffies + 4*HZ;
 663                 while (!netif_carrier_ok(ndev)) {
 664                         if (time_after(jiffies, atmost)) {
 665                                 printk(KERN_NOTICE
 666                                        "%s: timeout waiting for carrier\n",
 667                                        np->name);
 668                                 break;
 669                         }
 670                         cond_resched();
 671                 }
 672
 673                 /* If carrier appears to come up instantly, we don't
 674                  * trust it and pause so that we don't pump all our
 675                  * queued console messages into the bitbucket.
 676                  */
 677
 678                 if (time_before(jiffies, atleast)) {
 679                         printk(KERN_NOTICE "%s: carrier detect appears"
 680                                " untrustworthy, waiting 4 seconds\n",
 681                                np->name);
 682                         msleep(4000);
 683                 }
 684         }
 685
 686         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
 687                 memcpy(np->local_mac, ndev->dev_addr, 6);
 688
 689         if (!np->local_ip) {
 690                 rcu_read_lock();
 691                 in_dev = __in_dev_get_rcu(ndev);
 692
 693                 if (!in_dev || !in_dev->ifa_list) {
 694                         rcu_read_unlock();
 695                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 696                                np->name, np->dev_name);
 697                         err = -EDESTADDRREQ;
 698                         goto release;
 699                 }
 700
 701                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 702                 rcu_read_unlock();
 703                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 704                        np->name, HIPQUAD(np->local_ip));
 705         }
 706
 707         if (np->rx_hook) {
 708                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 709                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 710                 npinfo->rx_np = np;
 711                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 712         }
 713
 714         /* fill up the skb queue */
 715         refill_skbs();
 716
 717         /* last thing to do is link it to the net device structure */
 718         ndev->npinfo = npinfo;
 719
 720         /* avoid racing with NAPI reading npinfo */
 721         synchronize_rcu();
 722
 723         return 0;
 724
 725  release:
 726         if (!ndev->npinfo)
 727                 kfree(npinfo);
 728         np->dev = NULL;
 729         dev_put(ndev);
 730         return err;
 731 }
 732
 733 static int __init netpoll_init(void)
 734 {
 735         skb_queue_head_init(&skb_pool);
 736         return 0;
 737 }
 738 core_initcall(netpoll_init);
 739
 740 void netpoll_cleanup(struct netpoll *np)
 741 {
 742         struct netpoll_info *npinfo;
 743         unsigned long flags;
 744
 745         if (np->dev) {
 746                 npinfo = np->dev->npinfo;
 747                 if (npinfo) {
 748                         if (npinfo->rx_np == np) {
 749                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 750                                 npinfo->rx_np = NULL;
 751                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 752                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 753                         }
 754
 755                         np->dev->npinfo = NULL;
 756                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 757                                 skb_queue_purge(&npinfo->arp_tx);
 758                                 skb_queue_purge(&npinfo->txq);
 759                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 760                                 flush_scheduled_work();
 761
 762                                 kfree(npinfo);
 763                         }
 764                 }
 765
 766                 dev_put(np->dev);
 767         }
 768
 769         np->dev = NULL;
 770 }
 771
 772 int netpoll_trap(void)
 773 {
 774         return atomic_read(&trapped);
 775 }
 776
 777 void netpoll_set_trap(int trap)
 778 {
 779         if (trap)
 780                 atomic_inc(&trapped);
 781         else
 782                 atomic_dec(&trapped);
 783 }
 784
 785 EXPORT_SYMBOL(netpoll_set_trap);
 786 EXPORT_SYMBOL(netpoll_trap);
 787 EXPORT_SYMBOL(netpoll_parse_options);
 788 EXPORT_SYMBOL(netpoll_setup);
 789 EXPORT_SYMBOL(netpoll_cleanup);
 790 EXPORT_SYMBOL(netpoll_send_udp);
 791 EXPORT_SYMBOL(netpoll_poll);