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         unsigned char *sha;
 334         struct sk_buff *send_skb;
 335         struct netpoll *np = NULL;
 336
 337         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 338                 np = npinfo->rx_np;
 339         if (!np)
 340                 return;
 341
 342         /* No arp on this interface */
 343         if (skb->dev->flags & IFF_NOARP)
 344                 return;
 345
 346         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 347                                  (2 * skb->dev->addr_len) +
 348                                  (2 * sizeof(u32)))))
 349                 return;
 350
 351         skb->h.raw = skb->nh.raw = skb->data;
 352         arp = skb->nh.arph;
 353
 354         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 355              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 356             arp->ar_pro != htons(ETH_P_IP) ||
 357             arp->ar_op != htons(ARPOP_REQUEST))
 358                 return;
 359
 360         arp_ptr = (unsigned char *)(arp+1);
 361         /* save the location of the src hw addr */
 362         sha = arp_ptr;
 363         arp_ptr += skb->dev->addr_len;
 364         memcpy(&sip, arp_ptr, 4);
 365         arp_ptr += 4;
 366         /* if we actually cared about dst hw addr, it would get copied here */
 367         arp_ptr += skb->dev->addr_len;
 368         memcpy(&tip, arp_ptr, 4);
 369
 370         /* Should we ignore arp? */
 371         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 372                 return;
 373
 374         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 375         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 376                             LL_RESERVED_SPACE(np->dev));
 377
 378         if (!send_skb)
 379                 return;
 380
 381         send_skb->nh.raw = send_skb->data;
 382         arp = (struct arphdr *) skb_put(send_skb, size);
 383         send_skb->dev = skb->dev;
 384         send_skb->protocol = htons(ETH_P_ARP);
 385
 386         /* Fill the device header for the ARP frame */
 387
 388         if (np->dev->hard_header &&
 389             np->dev->hard_header(send_skb, skb->dev, ptype,
 390                                  sha, np->local_mac,
 391                                  send_skb->len) < 0) {
 392                 kfree_skb(send_skb);
 393                 return;
 394         }
 395
 396         /*
 397          * Fill out the arp protocol part.
 398          *
 399          * we only support ethernet device type,
 400          * which (according to RFC 1390) should always equal 1 (Ethernet).
 401          */
 402
 403         arp->ar_hrd = htons(np->dev->type);
 404         arp->ar_pro = htons(ETH_P_IP);
 405         arp->ar_hln = np->dev->addr_len;
 406         arp->ar_pln = 4;
 407         arp->ar_op = htons(type);
 408
 409         arp_ptr=(unsigned char *)(arp + 1);
 410         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 411         arp_ptr += np->dev->addr_len;
 412         memcpy(arp_ptr, &tip, 4);
 413         arp_ptr += 4;
 414         memcpy(arp_ptr, sha, np->dev->addr_len);
 415         arp_ptr += np->dev->addr_len;
 416         memcpy(arp_ptr, &sip, 4);
 417
 418         netpoll_send_skb(np, send_skb);
 419 }
 420
 421 int __netpoll_rx(struct sk_buff *skb)
 422 {
 423         int proto, len, ulen;
 424         struct iphdr *iph;
 425         struct udphdr *uh;
 426         struct netpoll_info *npi = skb->dev->npinfo;
 427         struct netpoll *np = npi->rx_np;
 428
 429         if (!np)
 430                 goto out;
 431         if (skb->dev->type != ARPHRD_ETHER)
 432                 goto out;
 433
 434         /* check if netpoll clients need ARP */
 435         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 436             atomic_read(&trapped)) {
 437                 skb_queue_tail(&npi->arp_tx, skb);
 438                 return 1;
 439         }
 440
 441         proto = ntohs(eth_hdr(skb)->h_proto);
 442         if (proto != ETH_P_IP)
 443                 goto out;
 444         if (skb->pkt_type == PACKET_OTHERHOST)
 445                 goto out;
 446         if (skb_shared(skb))
 447                 goto out;
 448
 449         iph = (struct iphdr *)skb->data;
 450         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 451                 goto out;
 452         if (iph->ihl < 5 || iph->version != 4)
 453                 goto out;
 454         if (!pskb_may_pull(skb, iph->ihl*4))
 455                 goto out;
 456         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 457                 goto out;
 458
 459         len = ntohs(iph->tot_len);
 460         if (skb->len < len || len < iph->ihl*4)
 461                 goto out;
 462
 463         if (iph->protocol != IPPROTO_UDP)
 464                 goto out;
 465
 466         len -= iph->ihl*4;
 467         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 468         ulen = ntohs(uh->len);
 469
 470         if (ulen != len)
 471                 goto out;
 472         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 473                 goto out;
 474         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 475                 goto out;
 476         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 477                 goto out;
 478         if (np->local_port && np->local_port != ntohs(uh->dest))
 479                 goto out;
 480
 481         np->rx_hook(np, ntohs(uh->source),
 482                     (char *)(uh+1),
 483                     ulen - sizeof(struct udphdr));
 484
 485         kfree_skb(skb);
 486         return 1;
 487
 488 out:
 489         if (atomic_read(&trapped)) {
 490                 kfree_skb(skb);
 491                 return 1;
 492         }
 493
 494         return 0;
 495 }
 496
 497 int netpoll_parse_options(struct netpoll *np, char *opt)
 498 {
 499         char *cur=opt, *delim;
 500
 501         if (*cur != '@') {
 502                 if ((delim = strchr(cur, '@')) == NULL)
 503                         goto parse_failed;
 504                 *delim = 0;
 505                 np->local_port = simple_strtol(cur, NULL, 10);
 506                 cur = delim;
 507         }
 508         cur++;
 509         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 510
 511         if (*cur != '/') {
 512                 if ((delim = strchr(cur, '/')) == NULL)
 513                         goto parse_failed;
 514                 *delim = 0;
 515                 np->local_ip = ntohl(in_aton(cur));
 516                 cur = delim;
 517
 518                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 519                        np->name, HIPQUAD(np->local_ip));
 520         }
 521         cur++;
 522
 523         if (*cur != ',') {
 524                 /* parse out dev name */
 525                 if ((delim = strchr(cur, ',')) == NULL)
 526                         goto parse_failed;
 527                 *delim = 0;
 528                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 529                 cur = delim;
 530         }
 531         cur++;
 532
 533         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 534
 535         if (*cur != '@') {
 536                 /* dst port */
 537                 if ((delim = strchr(cur, '@')) == NULL)
 538                         goto parse_failed;
 539                 *delim = 0;
 540                 np->remote_port = simple_strtol(cur, NULL, 10);
 541                 cur = delim;
 542         }
 543         cur++;
 544         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 545
 546         /* dst ip */
 547         if ((delim = strchr(cur, '/')) == NULL)
 548                 goto parse_failed;
 549         *delim = 0;
 550         np->remote_ip = ntohl(in_aton(cur));
 551         cur = delim + 1;
 552
 553         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 554                np->name, HIPQUAD(np->remote_ip));
 555
 556         if (*cur != 0) {
 557                 /* MAC address */
 558                 if ((delim = strchr(cur, ':')) == NULL)
 559                         goto parse_failed;
 560                 *delim = 0;
 561                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 562                 cur = delim + 1;
 563                 if ((delim = strchr(cur, ':')) == NULL)
 564                         goto parse_failed;
 565                 *delim = 0;
 566                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 567                 cur = delim + 1;
 568                 if ((delim = strchr(cur, ':')) == NULL)
 569                         goto parse_failed;
 570                 *delim = 0;
 571                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 572                 cur = delim + 1;
 573                 if ((delim = strchr(cur, ':')) == NULL)
 574                         goto parse_failed;
 575                 *delim = 0;
 576                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 577                 cur = delim + 1;
 578                 if ((delim = strchr(cur, ':')) == NULL)
 579                         goto parse_failed;
 580                 *delim = 0;
 581                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 582                 cur = delim + 1;
 583                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 584         }
 585
 586         printk(KERN_INFO "%s: remote ethernet address "
 587                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 588                np->name,
 589                np->remote_mac[0],
 590                np->remote_mac[1],
 591                np->remote_mac[2],
 592                np->remote_mac[3],
 593                np->remote_mac[4],
 594                np->remote_mac[5]);
 595
 596         return 0;
 597
 598  parse_failed:
 599         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 600                np->name, cur);
 601         return -1;
 602 }
 603
 604 int netpoll_setup(struct netpoll *np)
 605 {
 606         struct net_device *ndev = NULL;
 607         struct in_device *in_dev;
 608         struct netpoll_info *npinfo;
 609         unsigned long flags;
 610         int err;
 611
 612         if (np->dev_name)
 613                 ndev = dev_get_by_name(np->dev_name);
 614         if (!ndev) {
 615                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 616                        np->name, np->dev_name);
 617                 return -ENODEV;
 618         }
 619
 620         np->dev = ndev;
 621         if (!ndev->npinfo) {
 622                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 623                 if (!npinfo) {
 624                         err = -ENOMEM;
 625                         goto release;
 626                 }
 627
 628                 npinfo->rx_flags = 0;
 629                 npinfo->rx_np = NULL;
 630                 spin_lock_init(&npinfo->poll_lock);
 631                 npinfo->poll_owner = -1;
 632
 633                 spin_lock_init(&npinfo->rx_lock);
 634                 skb_queue_head_init(&npinfo->arp_tx);
 635                 skb_queue_head_init(&npinfo->txq);
 636                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 637
 638                 atomic_set(&npinfo->refcnt, 1);
 639         } else {
 640                 npinfo = ndev->npinfo;
 641                 atomic_inc(&npinfo->refcnt);
 642         }
 643
 644         if (!ndev->poll_controller) {
 645                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 646                        np->name, np->dev_name);
 647                 err = -ENOTSUPP;
 648                 goto release;
 649         }
 650
 651         if (!netif_running(ndev)) {
 652                 unsigned long atmost, atleast;
 653
 654                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 655                        np->name, np->dev_name);
 656
 657                 rtnl_lock();
 658                 err = dev_open(ndev);
 659                 rtnl_unlock();
 660
 661                 if (err) {
 662                         printk(KERN_ERR "%s: failed to open %s\n",
 663                                np->name, ndev->name);
 664                         goto release;
 665                 }
 666
 667                 atleast = jiffies + HZ/10;
 668                 atmost = jiffies + 4*HZ;
 669                 while (!netif_carrier_ok(ndev)) {
 670                         if (time_after(jiffies, atmost)) {
 671                                 printk(KERN_NOTICE
 672                                        "%s: timeout waiting for carrier\n",
 673                                        np->name);
 674                                 break;
 675                         }
 676                         cond_resched();
 677                 }
 678
 679                 /* If carrier appears to come up instantly, we don't
 680                  * trust it and pause so that we don't pump all our
 681                  * queued console messages into the bitbucket.
 682                  */
 683
 684                 if (time_before(jiffies, atleast)) {
 685                         printk(KERN_NOTICE "%s: carrier detect appears"
 686                                " untrustworthy, waiting 4 seconds\n",
 687                                np->name);
 688                         msleep(4000);
 689                 }
 690         }
 691
 692         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
 693                 memcpy(np->local_mac, ndev->dev_addr, 6);
 694
 695         if (!np->local_ip) {
 696                 rcu_read_lock();
 697                 in_dev = __in_dev_get_rcu(ndev);
 698
 699                 if (!in_dev || !in_dev->ifa_list) {
 700                         rcu_read_unlock();
 701                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 702                                np->name, np->dev_name);
 703                         err = -EDESTADDRREQ;
 704                         goto release;
 705                 }
 706
 707                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 708                 rcu_read_unlock();
 709                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 710                        np->name, HIPQUAD(np->local_ip));
 711         }
 712
 713         if (np->rx_hook) {
 714                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 715                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 716                 npinfo->rx_np = np;
 717                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 718         }
 719
 720         /* fill up the skb queue */
 721         refill_skbs();
 722
 723         /* last thing to do is link it to the net device structure */
 724         ndev->npinfo = npinfo;
 725
 726         /* avoid racing with NAPI reading npinfo */
 727         synchronize_rcu();
 728
 729         return 0;
 730
 731  release:
 732         if (!ndev->npinfo)
 733                 kfree(npinfo);
 734         np->dev = NULL;
 735         dev_put(ndev);
 736         return err;
 737 }
 738
 739 static int __init netpoll_init(void)
 740 {
 741         skb_queue_head_init(&skb_pool);
 742         return 0;
 743 }
 744 core_initcall(netpoll_init);
 745
 746 void netpoll_cleanup(struct netpoll *np)
 747 {
 748         struct netpoll_info *npinfo;
 749         unsigned long flags;
 750
 751         if (np->dev) {
 752                 npinfo = np->dev->npinfo;
 753                 if (npinfo) {
 754                         if (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
 761                         np->dev->npinfo = NULL;
 762                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 763                                 skb_queue_purge(&npinfo->arp_tx);
 764                                 skb_queue_purge(&npinfo->txq);
 765                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 766                                 flush_scheduled_work();
 767
 768                                 kfree(npinfo);
 769                         }
 770                 }
 771
 772                 dev_put(np->dev);
 773         }
 774
 775         np->dev = NULL;
 776 }
 777
 778 int netpoll_trap(void)
 779 {
 780         return atomic_read(&trapped);
 781 }
 782
 783 void netpoll_set_trap(int trap)
 784 {
 785         if (trap)
 786                 atomic_inc(&trapped);
 787         else
 788                 atomic_dec(&trapped);
 789 }
 790
 791 EXPORT_SYMBOL(netpoll_set_trap);
 792 EXPORT_SYMBOL(netpoll_trap);
 793 EXPORT_SYMBOL(netpoll_parse_options);
 794 EXPORT_SYMBOL(netpoll_setup);
 795 EXPORT_SYMBOL(netpoll_cleanup);
 796 EXPORT_SYMBOL(netpoll_send_udp);
 797 EXPORT_SYMBOL(netpoll_poll);