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/netdevice.h>
  13 #include <linux/etherdevice.h>
  14 #include <linux/string.h>
  15 #include <linux/if_arp.h>
  16 #include <linux/inetdevice.h>
  17 #include <linux/inet.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/netpoll.h>
  20 #include <linux/sched.h>
  21 #include <linux/delay.h>
  22 #include <linux/rcupdate.h>
  23 #include <linux/workqueue.h>
  24 #include <net/tcp.h>
  25 #include <net/udp.h>
  26 #include <asm/unaligned.h>
  27
  28 /*
  29  * We maintain a small pool of fully-sized skbs, to make sure the
  30  * message gets out even in extreme OOM situations.
  31  */
  32
  33 #define MAX_UDP_CHUNK 1460
  34 #define MAX_SKBS 32
  35 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
  36
  37 static struct sk_buff_head skb_pool;
  38
  39 static atomic_t trapped;
  40
  41 #define USEC_PER_POLL   50
  42 #define NETPOLL_RX_ENABLED  1
  43 #define NETPOLL_RX_DROP     2
  44
  45 #define MAX_SKB_SIZE \
  46                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  47                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  48
  49 static void zap_completion_queue(void);
  50 static void arp_reply(struct sk_buff *skb);
  51
  52 static void queue_process(struct work_struct *work)
  53 {
  54         struct netpoll_info *npinfo =
  55                 container_of(work, struct netpoll_info, tx_work.work);
  56         struct sk_buff *skb;
  57         unsigned long flags;
  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                 local_irq_save(flags);
  68                 netif_tx_lock(dev);
  69                 if (netif_queue_stopped(dev) ||
  70                     dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
  71                         skb_queue_head(&npinfo->txq, skb);
  72                         netif_tx_unlock(dev);
  73                         local_irq_restore(flags);
  74
  75                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  76                         return;
  77                 }
  78                 netif_tx_unlock(dev);
  79                 local_irq_restore(flags);
  80         }
  81 }
  82
  83 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  84                             unsigned short ulen, __be32 saddr, __be32 daddr)
  85 {
  86         __wsum psum;
  87
  88         if (uh->check == 0 || skb_csum_unnecessary(skb))
  89                 return 0;
  90
  91         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
  92
  93         if (skb->ip_summed == CHECKSUM_COMPLETE &&
  94             !csum_fold(csum_add(psum, skb->csum)))
  95                 return 0;
  96
  97         skb->csum = psum;
  98
  99         return __skb_checksum_complete(skb);
 100 }
 101
 102 /*
 103  * Check whether delayed processing was scheduled for our NIC. If so,
 104  * we attempt to grab the poll lock and use ->poll() to pump the card.
 105  * If this fails, either we've recursed in ->poll() or it's already
 106  * running on another CPU.
 107  *
 108  * Note: we don't mask interrupts with this lock because we're using
 109  * trylock here and interrupts are already disabled in the softirq
 110  * case. Further, we test the poll_owner to avoid recursion on UP
 111  * systems where the lock doesn't exist.
 112  *
 113  * In cases where there is bi-directional communications, reading only
 114  * one message at a time can lead to packets being dropped by the
 115  * network adapter, forcing superfluous retries and possibly timeouts.
 116  * Thus, we set our budget to greater than 1.
 117  */
 118 static void poll_napi(struct netpoll *np)
 119 {
 120         struct netpoll_info *npinfo = np->dev->npinfo;
 121         int budget = 16;
 122
 123         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
 124             npinfo->poll_owner != smp_processor_id() &&
 125             spin_trylock(&npinfo->poll_lock)) {
 126                 npinfo->rx_flags |= NETPOLL_RX_DROP;
 127                 atomic_inc(&trapped);
 128
 129                 np->dev->poll(np->dev, &budget);
 130
 131                 atomic_dec(&trapped);
 132                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 133                 spin_unlock(&npinfo->poll_lock);
 134         }
 135 }
 136
 137 static void service_arp_queue(struct netpoll_info *npi)
 138 {
 139         struct sk_buff *skb;
 140
 141         if (unlikely(!npi))
 142                 return;
 143
 144         skb = skb_dequeue(&npi->arp_tx);
 145
 146         while (skb != NULL) {
 147                 arp_reply(skb);
 148                 skb = skb_dequeue(&npi->arp_tx);
 149         }
 150 }
 151
 152 void netpoll_poll(struct netpoll *np)
 153 {
 154         if (!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
 155                 return;
 156
 157         /* Process pending work on NIC */
 158         np->dev->poll_controller(np->dev);
 159         if (np->dev->poll)
 160                 poll_napi(np);
 161
 162         service_arp_queue(np->dev->npinfo);
 163
 164         zap_completion_queue();
 165 }
 166
 167 static void refill_skbs(void)
 168 {
 169         struct sk_buff *skb;
 170         unsigned long flags;
 171
 172         spin_lock_irqsave(&skb_pool.lock, flags);
 173         while (skb_pool.qlen < MAX_SKBS) {
 174                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 175                 if (!skb)
 176                         break;
 177
 178                 __skb_queue_tail(&skb_pool, skb);
 179         }
 180         spin_unlock_irqrestore(&skb_pool.lock, flags);
 181 }
 182
 183 static void zap_completion_queue(void)
 184 {
 185         unsigned long flags;
 186         struct softnet_data *sd = &get_cpu_var(softnet_data);
 187
 188         if (sd->completion_queue) {
 189                 struct sk_buff *clist;
 190
 191                 local_irq_save(flags);
 192                 clist = sd->completion_queue;
 193                 sd->completion_queue = NULL;
 194                 local_irq_restore(flags);
 195
 196                 while (clist != NULL) {
 197                         struct sk_buff *skb = clist;
 198                         clist = clist->next;
 199                         if (skb->destructor)
 200                                 dev_kfree_skb_any(skb); /* put this one back */
 201                         else
 202                                 __kfree_skb(skb);
 203                 }
 204         }
 205
 206         put_cpu_var(softnet_data);
 207 }
 208
 209 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 210 {
 211         int count = 0;
 212         struct sk_buff *skb;
 213
 214         zap_completion_queue();
 215         refill_skbs();
 216 repeat:
 217
 218         skb = alloc_skb(len, GFP_ATOMIC);
 219         if (!skb)
 220                 skb = skb_dequeue(&skb_pool);
 221
 222         if (!skb) {
 223                 if (++count < 10) {
 224                         netpoll_poll(np);
 225                         goto repeat;
 226                 }
 227                 return NULL;
 228         }
 229
 230         atomic_set(&skb->users, 1);
 231         skb_reserve(skb, reserve);
 232         return skb;
 233 }
 234
 235 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 236 {
 237         int status = NETDEV_TX_BUSY;
 238         unsigned long tries;
 239         struct net_device *dev = np->dev;
 240         struct netpoll_info *npinfo = np->dev->npinfo;
 241
 242         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 243                 __kfree_skb(skb);
 244                 return;
 245         }
 246
 247         /* don't get messages out of order, and no recursion */
 248         if (skb_queue_len(&npinfo->txq) == 0 &&
 249                     npinfo->poll_owner != smp_processor_id()) {
 250                 unsigned long flags;
 251
 252                 local_irq_save(flags);
 253                 if (netif_tx_trylock(dev)) {
 254                         /* try until next clock tick */
 255                         for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 256                                         tries > 0; --tries) {
 257                                 if (!netif_queue_stopped(dev))
 258                                         status = dev->hard_start_xmit(skb, dev);
 259
 260                                 if (status == NETDEV_TX_OK)
 261                                         break;
 262
 263                                 /* tickle device maybe there is some cleanup */
 264                                 netpoll_poll(np);
 265
 266                                 udelay(USEC_PER_POLL);
 267                         }
 268                         netif_tx_unlock(dev);
 269                 }
 270                 local_irq_restore(flags);
 271         }
 272
 273         if (status != NETDEV_TX_OK) {
 274                 skb_queue_tail(&npinfo->txq, skb);
 275                 schedule_delayed_work(&npinfo->tx_work,0);
 276         }
 277 }
 278
 279 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 280 {
 281         int total_len, eth_len, ip_len, udp_len;
 282         struct sk_buff *skb;
 283         struct udphdr *udph;
 284         struct iphdr *iph;
 285         struct ethhdr *eth;
 286
 287         udp_len = len + sizeof(*udph);
 288         ip_len = eth_len = udp_len + sizeof(*iph);
 289         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 290
 291         skb = find_skb(np, total_len, total_len - len);
 292         if (!skb)
 293                 return;
 294
 295         skb_copy_to_linear_data(skb, msg, len);
 296         skb->len += len;
 297
 298         skb_push(skb, sizeof(*udph));
 299         skb_reset_transport_header(skb);
 300         udph = udp_hdr(skb);
 301         udph->source = htons(np->local_port);
 302         udph->dest = htons(np->remote_port);
 303         udph->len = htons(udp_len);
 304         udph->check = 0;
 305         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
 306                                         htonl(np->remote_ip),
 307                                         udp_len, IPPROTO_UDP,
 308                                         csum_partial((unsigned char *)udph, udp_len, 0));
 309         if (udph->check == 0)
 310                 udph->check = CSUM_MANGLED_0;
 311
 312         skb_push(skb, sizeof(*iph));
 313         skb_reset_network_header(skb);
 314         iph = ip_hdr(skb);
 315
 316         /* iph->version = 4; iph->ihl = 5; */
 317         put_unaligned(0x45, (unsigned char *)iph);
 318         iph->tos      = 0;
 319         put_unaligned(htons(ip_len), &(iph->tot_len));
 320         iph->id       = 0;
 321         iph->frag_off = 0;
 322         iph->ttl      = 64;
 323         iph->protocol = IPPROTO_UDP;
 324         iph->check    = 0;
 325         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 326         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 327         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 328
 329         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 330         skb_reset_mac_header(skb);
 331         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 332         memcpy(eth->h_source, np->local_mac, 6);
 333         memcpy(eth->h_dest, np->remote_mac, 6);
 334
 335         skb->dev = np->dev;
 336
 337         netpoll_send_skb(np, skb);
 338 }
 339
 340 static void arp_reply(struct sk_buff *skb)
 341 {
 342         struct netpoll_info *npinfo = skb->dev->npinfo;
 343         struct arphdr *arp;
 344         unsigned char *arp_ptr;
 345         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 346         __be32 sip, tip;
 347         unsigned char *sha;
 348         struct sk_buff *send_skb;
 349         struct netpoll *np = NULL;
 350
 351         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 352                 np = npinfo->rx_np;
 353         if (!np)
 354                 return;
 355
 356         /* No arp on this interface */
 357         if (skb->dev->flags & IFF_NOARP)
 358                 return;
 359
 360         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 361                                  (2 * skb->dev->addr_len) +
 362                                  (2 * sizeof(u32)))))
 363                 return;
 364
 365         skb_reset_network_header(skb);
 366         skb_reset_transport_header(skb);
 367         arp = arp_hdr(skb);
 368
 369         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 370              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 371             arp->ar_pro != htons(ETH_P_IP) ||
 372             arp->ar_op != htons(ARPOP_REQUEST))
 373                 return;
 374
 375         arp_ptr = (unsigned char *)(arp+1);
 376         /* save the location of the src hw addr */
 377         sha = arp_ptr;
 378         arp_ptr += skb->dev->addr_len;
 379         memcpy(&sip, arp_ptr, 4);
 380         arp_ptr += 4;
 381         /* if we actually cared about dst hw addr, it would get copied here */
 382         arp_ptr += skb->dev->addr_len;
 383         memcpy(&tip, arp_ptr, 4);
 384
 385         /* Should we ignore arp? */
 386         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 387                 return;
 388
 389         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 390         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 391                             LL_RESERVED_SPACE(np->dev));
 392
 393         if (!send_skb)
 394                 return;
 395
 396         skb_reset_network_header(send_skb);
 397         arp = (struct arphdr *) skb_put(send_skb, size);
 398         send_skb->dev = skb->dev;
 399         send_skb->protocol = htons(ETH_P_ARP);
 400
 401         /* Fill the device header for the ARP frame */
 402
 403         if (np->dev->hard_header &&
 404             np->dev->hard_header(send_skb, skb->dev, ptype,
 405                                  sha, np->local_mac,
 406                                  send_skb->len) < 0) {
 407                 kfree_skb(send_skb);
 408                 return;
 409         }
 410
 411         /*
 412          * Fill out the arp protocol part.
 413          *
 414          * we only support ethernet device type,
 415          * which (according to RFC 1390) should always equal 1 (Ethernet).
 416          */
 417
 418         arp->ar_hrd = htons(np->dev->type);
 419         arp->ar_pro = htons(ETH_P_IP);
 420         arp->ar_hln = np->dev->addr_len;
 421         arp->ar_pln = 4;
 422         arp->ar_op = htons(type);
 423
 424         arp_ptr=(unsigned char *)(arp + 1);
 425         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 426         arp_ptr += np->dev->addr_len;
 427         memcpy(arp_ptr, &tip, 4);
 428         arp_ptr += 4;
 429         memcpy(arp_ptr, sha, np->dev->addr_len);
 430         arp_ptr += np->dev->addr_len;
 431         memcpy(arp_ptr, &sip, 4);
 432
 433         netpoll_send_skb(np, send_skb);
 434 }
 435
 436 int __netpoll_rx(struct sk_buff *skb)
 437 {
 438         int proto, len, ulen;
 439         struct iphdr *iph;
 440         struct udphdr *uh;
 441         struct netpoll_info *npi = skb->dev->npinfo;
 442         struct netpoll *np = npi->rx_np;
 443
 444         if (!np)
 445                 goto out;
 446         if (skb->dev->type != ARPHRD_ETHER)
 447                 goto out;
 448
 449         /* check if netpoll clients need ARP */
 450         if (skb->protocol == htons(ETH_P_ARP) &&
 451             atomic_read(&trapped)) {
 452                 skb_queue_tail(&npi->arp_tx, skb);
 453                 return 1;
 454         }
 455
 456         proto = ntohs(eth_hdr(skb)->h_proto);
 457         if (proto != ETH_P_IP)
 458                 goto out;
 459         if (skb->pkt_type == PACKET_OTHERHOST)
 460                 goto out;
 461         if (skb_shared(skb))
 462                 goto out;
 463
 464         iph = (struct iphdr *)skb->data;
 465         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 466                 goto out;
 467         if (iph->ihl < 5 || iph->version != 4)
 468                 goto out;
 469         if (!pskb_may_pull(skb, iph->ihl*4))
 470                 goto out;
 471         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 472                 goto out;
 473
 474         len = ntohs(iph->tot_len);
 475         if (skb->len < len || len < iph->ihl*4)
 476                 goto out;
 477
 478         /*
 479          * Our transport medium may have padded the buffer out.
 480          * Now We trim to the true length of the frame.
 481          */
 482         if (pskb_trim_rcsum(skb, len))
 483                 goto out;
 484
 485         if (iph->protocol != IPPROTO_UDP)
 486                 goto out;
 487
 488         len -= iph->ihl*4;
 489         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 490         ulen = ntohs(uh->len);
 491
 492         if (ulen != len)
 493                 goto out;
 494         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 495                 goto out;
 496         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 497                 goto out;
 498         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 499                 goto out;
 500         if (np->local_port && np->local_port != ntohs(uh->dest))
 501                 goto out;
 502
 503         np->rx_hook(np, ntohs(uh->source),
 504                     (char *)(uh+1),
 505                     ulen - sizeof(struct udphdr));
 506
 507         kfree_skb(skb);
 508         return 1;
 509
 510 out:
 511         if (atomic_read(&trapped)) {
 512                 kfree_skb(skb);
 513                 return 1;
 514         }
 515
 516         return 0;
 517 }
 518
 519 int netpoll_parse_options(struct netpoll *np, char *opt)
 520 {
 521         char *cur=opt, *delim;
 522
 523         if (*cur != '@') {
 524                 if ((delim = strchr(cur, '@')) == NULL)
 525                         goto parse_failed;
 526                 *delim = 0;
 527                 np->local_port = simple_strtol(cur, NULL, 10);
 528                 cur = delim;
 529         }
 530         cur++;
 531         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 532
 533         if (*cur != '/') {
 534                 if ((delim = strchr(cur, '/')) == NULL)
 535                         goto parse_failed;
 536                 *delim = 0;
 537                 np->local_ip = ntohl(in_aton(cur));
 538                 cur = delim;
 539
 540                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 541                        np->name, HIPQUAD(np->local_ip));
 542         }
 543         cur++;
 544
 545         if (*cur != ',') {
 546                 /* parse out dev name */
 547                 if ((delim = strchr(cur, ',')) == NULL)
 548                         goto parse_failed;
 549                 *delim = 0;
 550                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 551                 cur = delim;
 552         }
 553         cur++;
 554
 555         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 556
 557         if (*cur != '@') {
 558                 /* dst port */
 559                 if ((delim = strchr(cur, '@')) == NULL)
 560                         goto parse_failed;
 561                 *delim = 0;
 562                 np->remote_port = simple_strtol(cur, NULL, 10);
 563                 cur = delim;
 564         }
 565         cur++;
 566         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 567
 568         /* dst ip */
 569         if ((delim = strchr(cur, '/')) == NULL)
 570                 goto parse_failed;
 571         *delim = 0;
 572         np->remote_ip = ntohl(in_aton(cur));
 573         cur = delim + 1;
 574
 575         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 576                np->name, HIPQUAD(np->remote_ip));
 577
 578         if (*cur != 0) {
 579                 /* MAC address */
 580                 if ((delim = strchr(cur, ':')) == NULL)
 581                         goto parse_failed;
 582                 *delim = 0;
 583                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 584                 cur = delim + 1;
 585                 if ((delim = strchr(cur, ':')) == NULL)
 586                         goto parse_failed;
 587                 *delim = 0;
 588                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 589                 cur = delim + 1;
 590                 if ((delim = strchr(cur, ':')) == NULL)
 591                         goto parse_failed;
 592                 *delim = 0;
 593                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 594                 cur = delim + 1;
 595                 if ((delim = strchr(cur, ':')) == NULL)
 596                         goto parse_failed;
 597                 *delim = 0;
 598                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 599                 cur = delim + 1;
 600                 if ((delim = strchr(cur, ':')) == NULL)
 601                         goto parse_failed;
 602                 *delim = 0;
 603                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 604                 cur = delim + 1;
 605                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 606         }
 607
 608         printk(KERN_INFO "%s: remote ethernet address "
 609                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 610                np->name,
 611                np->remote_mac[0],
 612                np->remote_mac[1],
 613                np->remote_mac[2],
 614                np->remote_mac[3],
 615                np->remote_mac[4],
 616                np->remote_mac[5]);
 617
 618         return 0;
 619
 620  parse_failed:
 621         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 622                np->name, cur);
 623         return -1;
 624 }
 625
 626 int netpoll_setup(struct netpoll *np)
 627 {
 628         struct net_device *ndev = NULL;
 629         struct in_device *in_dev;
 630         struct netpoll_info *npinfo;
 631         unsigned long flags;
 632         int err;
 633
 634         if (np->dev_name)
 635                 ndev = dev_get_by_name(np->dev_name);
 636         if (!ndev) {
 637                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 638                        np->name, np->dev_name);
 639                 return -ENODEV;
 640         }
 641
 642         np->dev = ndev;
 643         if (!ndev->npinfo) {
 644                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 645                 if (!npinfo) {
 646                         err = -ENOMEM;
 647                         goto release;
 648                 }
 649
 650                 npinfo->rx_flags = 0;
 651                 npinfo->rx_np = NULL;
 652                 spin_lock_init(&npinfo->poll_lock);
 653                 npinfo->poll_owner = -1;
 654
 655                 spin_lock_init(&npinfo->rx_lock);
 656                 skb_queue_head_init(&npinfo->arp_tx);
 657                 skb_queue_head_init(&npinfo->txq);
 658                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 659
 660                 atomic_set(&npinfo->refcnt, 1);
 661         } else {
 662                 npinfo = ndev->npinfo;
 663                 atomic_inc(&npinfo->refcnt);
 664         }
 665
 666         if (!ndev->poll_controller) {
 667                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 668                        np->name, np->dev_name);
 669                 err = -ENOTSUPP;
 670                 goto release;
 671         }
 672
 673         if (!netif_running(ndev)) {
 674                 unsigned long atmost, atleast;
 675
 676                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 677                        np->name, np->dev_name);
 678
 679                 rtnl_lock();
 680                 err = dev_open(ndev);
 681                 rtnl_unlock();
 682
 683                 if (err) {
 684                         printk(KERN_ERR "%s: failed to open %s\n",
 685                                np->name, ndev->name);
 686                         goto release;
 687                 }
 688
 689                 atleast = jiffies + HZ/10;
 690                 atmost = jiffies + 4*HZ;
 691                 while (!netif_carrier_ok(ndev)) {
 692                         if (time_after(jiffies, atmost)) {
 693                                 printk(KERN_NOTICE
 694                                        "%s: timeout waiting for carrier\n",
 695                                        np->name);
 696                                 break;
 697                         }
 698                         cond_resched();
 699                 }
 700
 701                 /* If carrier appears to come up instantly, we don't
 702                  * trust it and pause so that we don't pump all our
 703                  * queued console messages into the bitbucket.
 704                  */
 705
 706                 if (time_before(jiffies, atleast)) {
 707                         printk(KERN_NOTICE "%s: carrier detect appears"
 708                                " untrustworthy, waiting 4 seconds\n",
 709                                np->name);
 710                         msleep(4000);
 711                 }
 712         }
 713
 714         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
 715                 memcpy(np->local_mac, ndev->dev_addr, 6);
 716
 717         if (!np->local_ip) {
 718                 rcu_read_lock();
 719                 in_dev = __in_dev_get_rcu(ndev);
 720
 721                 if (!in_dev || !in_dev->ifa_list) {
 722                         rcu_read_unlock();
 723                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 724                                np->name, np->dev_name);
 725                         err = -EDESTADDRREQ;
 726                         goto release;
 727                 }
 728
 729                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 730                 rcu_read_unlock();
 731                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 732                        np->name, HIPQUAD(np->local_ip));
 733         }
 734
 735         if (np->rx_hook) {
 736                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 737                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 738                 npinfo->rx_np = np;
 739                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 740         }
 741
 742         /* fill up the skb queue */
 743         refill_skbs();
 744
 745         /* last thing to do is link it to the net device structure */
 746         ndev->npinfo = npinfo;
 747
 748         /* avoid racing with NAPI reading npinfo */
 749         synchronize_rcu();
 750
 751         return 0;
 752
 753  release:
 754         if (!ndev->npinfo)
 755                 kfree(npinfo);
 756         np->dev = NULL;
 757         dev_put(ndev);
 758         return err;
 759 }
 760
 761 static int __init netpoll_init(void)
 762 {
 763         skb_queue_head_init(&skb_pool);
 764         return 0;
 765 }
 766 core_initcall(netpoll_init);
 767
 768 void netpoll_cleanup(struct netpoll *np)
 769 {
 770         struct netpoll_info *npinfo;
 771         unsigned long flags;
 772
 773         if (np->dev) {
 774                 npinfo = np->dev->npinfo;
 775                 if (npinfo) {
 776                         if (npinfo->rx_np == np) {
 777                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 778                                 npinfo->rx_np = NULL;
 779                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 780                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 781                         }
 782
 783                         np->dev->npinfo = NULL;
 784                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 785                                 skb_queue_purge(&npinfo->arp_tx);
 786                                 skb_queue_purge(&npinfo->txq);
 787                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 788                                 flush_scheduled_work();
 789
 790                                 kfree(npinfo);
 791                         }
 792                 }
 793
 794                 dev_put(np->dev);
 795         }
 796
 797         np->dev = NULL;
 798 }
 799
 800 int netpoll_trap(void)
 801 {
 802         return atomic_read(&trapped);
 803 }
 804
 805 void netpoll_set_trap(int trap)
 806 {
 807         if (trap)
 808                 atomic_inc(&trapped);
 809         else
 810                 atomic_dec(&trapped);
 811 }
 812
 813 EXPORT_SYMBOL(netpoll_set_trap);
 814 EXPORT_SYMBOL(netpoll_trap);
 815 EXPORT_SYMBOL(netpoll_parse_options);
 816 EXPORT_SYMBOL(netpoll_setup);
 817 EXPORT_SYMBOL(netpoll_cleanup);
 818 EXPORT_SYMBOL(netpoll_send_udp);
 819 EXPORT_SYMBOL(netpoll_poll);