git.oblomov.eu Git - linux-2.6/blob - net/core/netpoll.c

   1 /*
   2  * Common framework for low-level network console, dump, and debugger code
   3  *
   4  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
   5  *
   6  * based on the netconsole code from:
   7  *
   8  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
   9  * Copyright (C) 2002  Red Hat, Inc.
  10  */
  11
  12 #include <linux/smp_lock.h>
  13 #include <linux/netdevice.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/string.h>
  16 #include <linux/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                 local_bh_disable();     /* Where's netif_tx_trylock_bh()? */
 247                 if (netif_tx_trylock(dev)) {
 248                         /* try until next clock tick */
 249                         for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 250                                         tries > 0; --tries) {
 251                                 if (!netif_queue_stopped(dev))
 252                                         status = dev->hard_start_xmit(skb, dev);
 253
 254                                 if (status == NETDEV_TX_OK)
 255                                         break;
 256
 257                                 /* tickle device maybe there is some cleanup */
 258                                 netpoll_poll(np);
 259
 260                                 udelay(USEC_PER_POLL);
 261                         }
 262                         netif_tx_unlock(dev);
 263                 }
 264                 local_bh_enable();
 265         }
 266
 267         if (status != NETDEV_TX_OK) {
 268                 skb_queue_tail(&npinfo->txq, skb);
 269                 schedule_delayed_work(&npinfo->tx_work,0);
 270         }
 271 }
 272
 273 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 274 {
 275         int total_len, eth_len, ip_len, udp_len;
 276         struct sk_buff *skb;
 277         struct udphdr *udph;
 278         struct iphdr *iph;
 279         struct ethhdr *eth;
 280
 281         udp_len = len + sizeof(*udph);
 282         ip_len = eth_len = udp_len + sizeof(*iph);
 283         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 284
 285         skb = find_skb(np, total_len, total_len - len);
 286         if (!skb)
 287                 return;
 288
 289         memcpy(skb->data, msg, len);
 290         skb->len += len;
 291
 292         skb->h.uh = udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 293         udph->source = htons(np->local_port);
 294         udph->dest = htons(np->remote_port);
 295         udph->len = htons(udp_len);
 296         udph->check = 0;
 297         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
 298                                         htonl(np->remote_ip),
 299                                         udp_len, IPPROTO_UDP,
 300                                         csum_partial((unsigned char *)udph, udp_len, 0));
 301         if (udph->check == 0)
 302                 udph->check = CSUM_MANGLED_0;
 303
 304         skb->nh.iph = iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 305
 306         /* iph->version = 4; iph->ihl = 5; */
 307         put_unaligned(0x45, (unsigned char *)iph);
 308         iph->tos      = 0;
 309         put_unaligned(htons(ip_len), &(iph->tot_len));
 310         iph->id       = 0;
 311         iph->frag_off = 0;
 312         iph->ttl      = 64;
 313         iph->protocol = IPPROTO_UDP;
 314         iph->check    = 0;
 315         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 316         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 317         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 318
 319         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 320         skb->mac.raw = skb->data;
 321         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 322         memcpy(eth->h_source, np->local_mac, 6);
 323         memcpy(eth->h_dest, np->remote_mac, 6);
 324
 325         skb->dev = np->dev;
 326
 327         netpoll_send_skb(np, skb);
 328 }
 329
 330 static void arp_reply(struct sk_buff *skb)
 331 {
 332         struct netpoll_info *npinfo = skb->dev->npinfo;
 333         struct arphdr *arp;
 334         unsigned char *arp_ptr;
 335         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 336         __be32 sip, tip;
 337         unsigned char *sha;
 338         struct sk_buff *send_skb;
 339         struct netpoll *np = NULL;
 340
 341         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 342                 np = npinfo->rx_np;
 343         if (!np)
 344                 return;
 345
 346         /* No arp on this interface */
 347         if (skb->dev->flags & IFF_NOARP)
 348                 return;
 349
 350         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 351                                  (2 * skb->dev->addr_len) +
 352                                  (2 * sizeof(u32)))))
 353                 return;
 354
 355         skb->h.raw = skb->nh.raw = skb->data;
 356         arp = skb->nh.arph;
 357
 358         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 359              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 360             arp->ar_pro != htons(ETH_P_IP) ||
 361             arp->ar_op != htons(ARPOP_REQUEST))
 362                 return;
 363
 364         arp_ptr = (unsigned char *)(arp+1);
 365         /* save the location of the src hw addr */
 366         sha = arp_ptr;
 367         arp_ptr += skb->dev->addr_len;
 368         memcpy(&sip, arp_ptr, 4);
 369         arp_ptr += 4;
 370         /* if we actually cared about dst hw addr, it would get copied here */
 371         arp_ptr += skb->dev->addr_len;
 372         memcpy(&tip, arp_ptr, 4);
 373
 374         /* Should we ignore arp? */
 375         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 376                 return;
 377
 378         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 379         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 380                             LL_RESERVED_SPACE(np->dev));
 381
 382         if (!send_skb)
 383                 return;
 384
 385         send_skb->nh.raw = send_skb->data;
 386         arp = (struct arphdr *) skb_put(send_skb, size);
 387         send_skb->dev = skb->dev;
 388         send_skb->protocol = htons(ETH_P_ARP);
 389
 390         /* Fill the device header for the ARP frame */
 391
 392         if (np->dev->hard_header &&
 393             np->dev->hard_header(send_skb, skb->dev, ptype,
 394                                  sha, np->local_mac,
 395                                  send_skb->len) < 0) {
 396                 kfree_skb(send_skb);
 397                 return;
 398         }
 399
 400         /*
 401          * Fill out the arp protocol part.
 402          *
 403          * we only support ethernet device type,
 404          * which (according to RFC 1390) should always equal 1 (Ethernet).
 405          */
 406
 407         arp->ar_hrd = htons(np->dev->type);
 408         arp->ar_pro = htons(ETH_P_IP);
 409         arp->ar_hln = np->dev->addr_len;
 410         arp->ar_pln = 4;
 411         arp->ar_op = htons(type);
 412
 413         arp_ptr=(unsigned char *)(arp + 1);
 414         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 415         arp_ptr += np->dev->addr_len;
 416         memcpy(arp_ptr, &tip, 4);
 417         arp_ptr += 4;
 418         memcpy(arp_ptr, sha, np->dev->addr_len);
 419         arp_ptr += np->dev->addr_len;
 420         memcpy(arp_ptr, &sip, 4);
 421
 422         netpoll_send_skb(np, send_skb);
 423 }
 424
 425 int __netpoll_rx(struct sk_buff *skb)
 426 {
 427         int proto, len, ulen;
 428         struct iphdr *iph;
 429         struct udphdr *uh;
 430         struct netpoll_info *npi = skb->dev->npinfo;
 431         struct netpoll *np = npi->rx_np;
 432
 433         if (!np)
 434                 goto out;
 435         if (skb->dev->type != ARPHRD_ETHER)
 436                 goto out;
 437
 438         /* check if netpoll clients need ARP */
 439         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 440             atomic_read(&trapped)) {
 441                 skb_queue_tail(&npi->arp_tx, skb);
 442                 return 1;
 443         }
 444
 445         proto = ntohs(eth_hdr(skb)->h_proto);
 446         if (proto != ETH_P_IP)
 447                 goto out;
 448         if (skb->pkt_type == PACKET_OTHERHOST)
 449                 goto out;
 450         if (skb_shared(skb))
 451                 goto out;
 452
 453         iph = (struct iphdr *)skb->data;
 454         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 455                 goto out;
 456         if (iph->ihl < 5 || iph->version != 4)
 457                 goto out;
 458         if (!pskb_may_pull(skb, iph->ihl*4))
 459                 goto out;
 460         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 461                 goto out;
 462
 463         len = ntohs(iph->tot_len);
 464         if (skb->len < len || len < iph->ihl*4)
 465                 goto out;
 466
 467         if (iph->protocol != IPPROTO_UDP)
 468                 goto out;
 469
 470         len -= iph->ihl*4;
 471         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 472         ulen = ntohs(uh->len);
 473
 474         if (ulen != len)
 475                 goto out;
 476         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 477                 goto out;
 478         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 479                 goto out;
 480         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 481                 goto out;
 482         if (np->local_port && np->local_port != ntohs(uh->dest))
 483                 goto out;
 484
 485         np->rx_hook(np, ntohs(uh->source),
 486                     (char *)(uh+1),
 487                     ulen - sizeof(struct udphdr));
 488
 489         kfree_skb(skb);
 490         return 1;
 491
 492 out:
 493         if (atomic_read(&trapped)) {
 494                 kfree_skb(skb);
 495                 return 1;
 496         }
 497
 498         return 0;
 499 }
 500
 501 int netpoll_parse_options(struct netpoll *np, char *opt)
 502 {
 503         char *cur=opt, *delim;
 504
 505         if (*cur != '@') {
 506                 if ((delim = strchr(cur, '@')) == NULL)
 507                         goto parse_failed;
 508                 *delim = 0;
 509                 np->local_port = simple_strtol(cur, NULL, 10);
 510                 cur = delim;
 511         }
 512         cur++;
 513         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 514
 515         if (*cur != '/') {
 516                 if ((delim = strchr(cur, '/')) == NULL)
 517                         goto parse_failed;
 518                 *delim = 0;
 519                 np->local_ip = ntohl(in_aton(cur));
 520                 cur = delim;
 521
 522                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 523                        np->name, HIPQUAD(np->local_ip));
 524         }
 525         cur++;
 526
 527         if (*cur != ',') {
 528                 /* parse out dev name */
 529                 if ((delim = strchr(cur, ',')) == NULL)
 530                         goto parse_failed;
 531                 *delim = 0;
 532                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 533                 cur = delim;
 534         }
 535         cur++;
 536
 537         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 538
 539         if (*cur != '@') {
 540                 /* dst port */
 541                 if ((delim = strchr(cur, '@')) == NULL)
 542                         goto parse_failed;
 543                 *delim = 0;
 544                 np->remote_port = simple_strtol(cur, NULL, 10);
 545                 cur = delim;
 546         }
 547         cur++;
 548         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 549
 550         /* dst ip */
 551         if ((delim = strchr(cur, '/')) == NULL)
 552                 goto parse_failed;
 553         *delim = 0;
 554         np->remote_ip = ntohl(in_aton(cur));
 555         cur = delim + 1;
 556
 557         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 558                np->name, HIPQUAD(np->remote_ip));
 559
 560         if (*cur != 0) {
 561                 /* MAC address */
 562                 if ((delim = strchr(cur, ':')) == NULL)
 563                         goto parse_failed;
 564                 *delim = 0;
 565                 np->remote_mac[0] = 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[1] = 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[2] = simple_strtol(cur, NULL, 16);
 576                 cur = delim + 1;
 577                 if ((delim = strchr(cur, ':')) == NULL)
 578                         goto parse_failed;
 579                 *delim = 0;
 580                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 581                 cur = delim + 1;
 582                 if ((delim = strchr(cur, ':')) == NULL)
 583                         goto parse_failed;
 584                 *delim = 0;
 585                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 586                 cur = delim + 1;
 587                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 588         }
 589
 590         printk(KERN_INFO "%s: remote ethernet address "
 591                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 592                np->name,
 593                np->remote_mac[0],
 594                np->remote_mac[1],
 595                np->remote_mac[2],
 596                np->remote_mac[3],
 597                np->remote_mac[4],
 598                np->remote_mac[5]);
 599
 600         return 0;
 601
 602  parse_failed:
 603         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 604                np->name, cur);
 605         return -1;
 606 }
 607
 608 int netpoll_setup(struct netpoll *np)
 609 {
 610         struct net_device *ndev = NULL;
 611         struct in_device *in_dev;
 612         struct netpoll_info *npinfo;
 613         unsigned long flags;
 614         int err;
 615
 616         if (np->dev_name)
 617                 ndev = dev_get_by_name(np->dev_name);
 618         if (!ndev) {
 619                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 620                        np->name, np->dev_name);
 621                 return -ENODEV;
 622         }
 623
 624         np->dev = ndev;
 625         if (!ndev->npinfo) {
 626                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 627                 if (!npinfo) {
 628                         err = -ENOMEM;
 629                         goto release;
 630                 }
 631
 632                 npinfo->rx_flags = 0;
 633                 npinfo->rx_np = NULL;
 634                 spin_lock_init(&npinfo->poll_lock);
 635                 npinfo->poll_owner = -1;
 636
 637                 spin_lock_init(&npinfo->rx_lock);
 638                 skb_queue_head_init(&npinfo->arp_tx);
 639                 skb_queue_head_init(&npinfo->txq);
 640                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 641
 642                 atomic_set(&npinfo->refcnt, 1);
 643         } else {
 644                 npinfo = ndev->npinfo;
 645                 atomic_inc(&npinfo->refcnt);
 646         }
 647
 648         if (!ndev->poll_controller) {
 649                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 650                        np->name, np->dev_name);
 651                 err = -ENOTSUPP;
 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_lock();
 662                 err = dev_open(ndev);
 663                 rtnl_unlock();
 664
 665                 if (err) {
 666                         printk(KERN_ERR "%s: failed to open %s\n",
 667                                np->name, ndev->name);
 668                         goto release;
 669                 }
 670
 671                 atleast = jiffies + HZ/10;
 672                 atmost = jiffies + 4*HZ;
 673                 while (!netif_carrier_ok(ndev)) {
 674                         if (time_after(jiffies, atmost)) {
 675                                 printk(KERN_NOTICE
 676                                        "%s: timeout waiting for carrier\n",
 677                                        np->name);
 678                                 break;
 679                         }
 680                         cond_resched();
 681                 }
 682
 683                 /* If carrier appears to come up instantly, we don't
 684                  * trust it and pause so that we don't pump all our
 685                  * queued console messages into the bitbucket.
 686                  */
 687
 688                 if (time_before(jiffies, atleast)) {
 689                         printk(KERN_NOTICE "%s: carrier detect appears"
 690                                " untrustworthy, waiting 4 seconds\n",
 691                                np->name);
 692                         msleep(4000);
 693                 }
 694         }
 695
 696         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
 697                 memcpy(np->local_mac, ndev->dev_addr, 6);
 698
 699         if (!np->local_ip) {
 700                 rcu_read_lock();
 701                 in_dev = __in_dev_get_rcu(ndev);
 702
 703                 if (!in_dev || !in_dev->ifa_list) {
 704                         rcu_read_unlock();
 705                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 706                                np->name, np->dev_name);
 707                         err = -EDESTADDRREQ;
 708                         goto release;
 709                 }
 710
 711                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 712                 rcu_read_unlock();
 713                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 714                        np->name, HIPQUAD(np->local_ip));
 715         }
 716
 717         if (np->rx_hook) {
 718                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 719                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 720                 npinfo->rx_np = np;
 721                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 722         }
 723
 724         /* fill up the skb queue */
 725         refill_skbs();
 726
 727         /* last thing to do is link it to the net device structure */
 728         ndev->npinfo = npinfo;
 729
 730         /* avoid racing with NAPI reading npinfo */
 731         synchronize_rcu();
 732
 733         return 0;
 734
 735  release:
 736         if (!ndev->npinfo)
 737                 kfree(npinfo);
 738         np->dev = NULL;
 739         dev_put(ndev);
 740         return err;
 741 }
 742
 743 static int __init netpoll_init(void)
 744 {
 745         skb_queue_head_init(&skb_pool);
 746         return 0;
 747 }
 748 core_initcall(netpoll_init);
 749
 750 void netpoll_cleanup(struct netpoll *np)
 751 {
 752         struct netpoll_info *npinfo;
 753         unsigned long flags;
 754
 755         if (np->dev) {
 756                 npinfo = np->dev->npinfo;
 757                 if (npinfo) {
 758                         if (npinfo->rx_np == np) {
 759                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 760                                 npinfo->rx_np = NULL;
 761                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 762                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 763                         }
 764
 765                         np->dev->npinfo = NULL;
 766                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 767                                 skb_queue_purge(&npinfo->arp_tx);
 768                                 skb_queue_purge(&npinfo->txq);
 769                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 770                                 flush_scheduled_work();
 771
 772                                 kfree(npinfo);
 773                         }
 774                 }
 775
 776                 dev_put(np->dev);
 777         }
 778
 779         np->dev = NULL;
 780 }
 781
 782 int netpoll_trap(void)
 783 {
 784         return atomic_read(&trapped);
 785 }
 786
 787 void netpoll_set_trap(int trap)
 788 {
 789         if (trap)
 790                 atomic_inc(&trapped);
 791         else
 792                 atomic_dec(&trapped);
 793 }
 794
 795 EXPORT_SYMBOL(netpoll_set_trap);
 796 EXPORT_SYMBOL(netpoll_trap);
 797 EXPORT_SYMBOL(netpoll_parse_options);
 798 EXPORT_SYMBOL(netpoll_setup);
 799 EXPORT_SYMBOL(netpoll_cleanup);
 800 EXPORT_SYMBOL(netpoll_send_udp);
 801 EXPORT_SYMBOL(netpoll_poll);