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         unsigned long flags;
  59
  60         while ((skb = skb_dequeue(&npinfo->txq))) {
  61                 struct net_device *dev = skb->dev;
  62
  63                 if (!netif_device_present(dev) || !netif_running(dev)) {
  64                         __kfree_skb(skb);
  65                         continue;
  66                 }
  67
  68                 local_irq_save(flags);
  69                 netif_tx_lock(dev);
  70                 if (netif_queue_stopped(dev) ||
  71                     dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
  72                         skb_queue_head(&npinfo->txq, skb);
  73                         netif_tx_unlock(dev);
  74                         local_irq_restore(flags);
  75
  76                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  77                         return;
  78                 }
  79                 netif_tx_unlock(dev);
  80                 local_irq_restore(flags);
  81         }
  82 }
  83
  84 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  85                             unsigned short ulen, __be32 saddr, __be32 daddr)
  86 {
  87         __wsum psum;
  88
  89         if (uh->check == 0 || skb_csum_unnecessary(skb))
  90                 return 0;
  91
  92         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
  93
  94         if (skb->ip_summed == CHECKSUM_COMPLETE &&
  95             !csum_fold(csum_add(psum, skb->csum)))
  96                 return 0;
  97
  98         skb->csum = psum;
  99
 100         return __skb_checksum_complete(skb);
 101 }
 102
 103 /*
 104  * Check whether delayed processing was scheduled for our NIC. If so,
 105  * we attempt to grab the poll lock and use ->poll() to pump the card.
 106  * If this fails, either we've recursed in ->poll() or it's already
 107  * running on another CPU.
 108  *
 109  * Note: we don't mask interrupts with this lock because we're using
 110  * trylock here and interrupts are already disabled in the softirq
 111  * case. Further, we test the poll_owner to avoid recursion on UP
 112  * systems where the lock doesn't exist.
 113  *
 114  * In cases where there is bi-directional communications, reading only
 115  * one message at a time can lead to packets being dropped by the
 116  * network adapter, forcing superfluous retries and possibly timeouts.
 117  * Thus, we set our budget to greater than 1.
 118  */
 119 static void poll_napi(struct netpoll *np)
 120 {
 121         struct netpoll_info *npinfo = np->dev->npinfo;
 122         int budget = 16;
 123
 124         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
 125             npinfo->poll_owner != smp_processor_id() &&
 126             spin_trylock(&npinfo->poll_lock)) {
 127                 npinfo->rx_flags |= NETPOLL_RX_DROP;
 128                 atomic_inc(&trapped);
 129
 130                 np->dev->poll(np->dev, &budget);
 131
 132                 atomic_dec(&trapped);
 133                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 134                 spin_unlock(&npinfo->poll_lock);
 135         }
 136 }
 137
 138 static void service_arp_queue(struct netpoll_info *npi)
 139 {
 140         struct sk_buff *skb;
 141
 142         if (unlikely(!npi))
 143                 return;
 144
 145         skb = skb_dequeue(&npi->arp_tx);
 146
 147         while (skb != NULL) {
 148                 arp_reply(skb);
 149                 skb = skb_dequeue(&npi->arp_tx);
 150         }
 151 }
 152
 153 void netpoll_poll(struct netpoll *np)
 154 {
 155         if (!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
 156                 return;
 157
 158         /* Process pending work on NIC */
 159         np->dev->poll_controller(np->dev);
 160         if (np->dev->poll)
 161                 poll_napi(np);
 162
 163         service_arp_queue(np->dev->npinfo);
 164
 165         zap_completion_queue();
 166 }
 167
 168 static void refill_skbs(void)
 169 {
 170         struct sk_buff *skb;
 171         unsigned long flags;
 172
 173         spin_lock_irqsave(&skb_pool.lock, flags);
 174         while (skb_pool.qlen < MAX_SKBS) {
 175                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 176                 if (!skb)
 177                         break;
 178
 179                 __skb_queue_tail(&skb_pool, skb);
 180         }
 181         spin_unlock_irqrestore(&skb_pool.lock, flags);
 182 }
 183
 184 static void zap_completion_queue(void)
 185 {
 186         unsigned long flags;
 187         struct softnet_data *sd = &get_cpu_var(softnet_data);
 188
 189         if (sd->completion_queue) {
 190                 struct sk_buff *clist;
 191
 192                 local_irq_save(flags);
 193                 clist = sd->completion_queue;
 194                 sd->completion_queue = NULL;
 195                 local_irq_restore(flags);
 196
 197                 while (clist != NULL) {
 198                         struct sk_buff *skb = clist;
 199                         clist = clist->next;
 200                         if (skb->destructor)
 201                                 dev_kfree_skb_any(skb); /* put this one back */
 202                         else
 203                                 __kfree_skb(skb);
 204                 }
 205         }
 206
 207         put_cpu_var(softnet_data);
 208 }
 209
 210 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 211 {
 212         int count = 0;
 213         struct sk_buff *skb;
 214
 215         zap_completion_queue();
 216         refill_skbs();
 217 repeat:
 218
 219         skb = alloc_skb(len, GFP_ATOMIC);
 220         if (!skb)
 221                 skb = skb_dequeue(&skb_pool);
 222
 223         if (!skb) {
 224                 if (++count < 10) {
 225                         netpoll_poll(np);
 226                         goto repeat;
 227                 }
 228                 return NULL;
 229         }
 230
 231         atomic_set(&skb->users, 1);
 232         skb_reserve(skb, reserve);
 233         return skb;
 234 }
 235
 236 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 237 {
 238         int status = NETDEV_TX_BUSY;
 239         unsigned long tries;
 240         struct net_device *dev = np->dev;
 241         struct netpoll_info *npinfo = np->dev->npinfo;
 242
 243         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 244                 __kfree_skb(skb);
 245                 return;
 246         }
 247
 248         /* don't get messages out of order, and no recursion */
 249         if (skb_queue_len(&npinfo->txq) == 0 &&
 250                     npinfo->poll_owner != smp_processor_id()) {
 251                 unsigned long flags;
 252
 253                 local_irq_save(flags);
 254                 if (netif_tx_trylock(dev)) {
 255                         /* try until next clock tick */
 256                         for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 257                                         tries > 0; --tries) {
 258                                 if (!netif_queue_stopped(dev))
 259                                         status = dev->hard_start_xmit(skb, dev);
 260
 261                                 if (status == NETDEV_TX_OK)
 262                                         break;
 263
 264                                 /* tickle device maybe there is some cleanup */
 265                                 netpoll_poll(np);
 266
 267                                 udelay(USEC_PER_POLL);
 268                         }
 269                         netif_tx_unlock(dev);
 270                 }
 271                 local_irq_restore(flags);
 272         }
 273
 274         if (status != NETDEV_TX_OK) {
 275                 skb_queue_tail(&npinfo->txq, skb);
 276                 schedule_delayed_work(&npinfo->tx_work,0);
 277         }
 278 }
 279
 280 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 281 {
 282         int total_len, eth_len, ip_len, udp_len;
 283         struct sk_buff *skb;
 284         struct udphdr *udph;
 285         struct iphdr *iph;
 286         struct ethhdr *eth;
 287
 288         udp_len = len + sizeof(*udph);
 289         ip_len = eth_len = udp_len + sizeof(*iph);
 290         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 291
 292         skb = find_skb(np, total_len, total_len - len);
 293         if (!skb)
 294                 return;
 295
 296         skb_copy_to_linear_data(skb, msg, len);
 297         skb->len += len;
 298
 299         skb_push(skb, sizeof(*udph));
 300         skb_reset_transport_header(skb);
 301         udph = udp_hdr(skb);
 302         udph->source = htons(np->local_port);
 303         udph->dest = htons(np->remote_port);
 304         udph->len = htons(udp_len);
 305         udph->check = 0;
 306         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
 307                                         htonl(np->remote_ip),
 308                                         udp_len, IPPROTO_UDP,
 309                                         csum_partial((unsigned char *)udph, udp_len, 0));
 310         if (udph->check == 0)
 311                 udph->check = CSUM_MANGLED_0;
 312
 313         skb_push(skb, sizeof(*iph));
 314         skb_reset_network_header(skb);
 315         iph = ip_hdr(skb);
 316
 317         /* iph->version = 4; iph->ihl = 5; */
 318         put_unaligned(0x45, (unsigned char *)iph);
 319         iph->tos      = 0;
 320         put_unaligned(htons(ip_len), &(iph->tot_len));
 321         iph->id       = 0;
 322         iph->frag_off = 0;
 323         iph->ttl      = 64;
 324         iph->protocol = IPPROTO_UDP;
 325         iph->check    = 0;
 326         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 327         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 328         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 329
 330         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 331         skb_reset_mac_header(skb);
 332         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 333         memcpy(eth->h_source, np->local_mac, 6);
 334         memcpy(eth->h_dest, np->remote_mac, 6);
 335
 336         skb->dev = np->dev;
 337
 338         netpoll_send_skb(np, skb);
 339 }
 340
 341 static void arp_reply(struct sk_buff *skb)
 342 {
 343         struct netpoll_info *npinfo = skb->dev->npinfo;
 344         struct arphdr *arp;
 345         unsigned char *arp_ptr;
 346         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 347         __be32 sip, tip;
 348         unsigned char *sha;
 349         struct sk_buff *send_skb;
 350         struct netpoll *np = NULL;
 351
 352         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 353                 np = npinfo->rx_np;
 354         if (!np)
 355                 return;
 356
 357         /* No arp on this interface */
 358         if (skb->dev->flags & IFF_NOARP)
 359                 return;
 360
 361         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 362                                  (2 * skb->dev->addr_len) +
 363                                  (2 * sizeof(u32)))))
 364                 return;
 365
 366         skb_reset_network_header(skb);
 367         skb_reset_transport_header(skb);
 368         arp = arp_hdr(skb);
 369
 370         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 371              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 372             arp->ar_pro != htons(ETH_P_IP) ||
 373             arp->ar_op != htons(ARPOP_REQUEST))
 374                 return;
 375
 376         arp_ptr = (unsigned char *)(arp+1);
 377         /* save the location of the src hw addr */
 378         sha = arp_ptr;
 379         arp_ptr += skb->dev->addr_len;
 380         memcpy(&sip, arp_ptr, 4);
 381         arp_ptr += 4;
 382         /* if we actually cared about dst hw addr, it would get copied here */
 383         arp_ptr += skb->dev->addr_len;
 384         memcpy(&tip, arp_ptr, 4);
 385
 386         /* Should we ignore arp? */
 387         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 388                 return;
 389
 390         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 391         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 392                             LL_RESERVED_SPACE(np->dev));
 393
 394         if (!send_skb)
 395                 return;
 396
 397         skb_reset_network_header(send_skb);
 398         arp = (struct arphdr *) skb_put(send_skb, size);
 399         send_skb->dev = skb->dev;
 400         send_skb->protocol = htons(ETH_P_ARP);
 401
 402         /* Fill the device header for the ARP frame */
 403
 404         if (np->dev->hard_header &&
 405             np->dev->hard_header(send_skb, skb->dev, ptype,
 406                                  sha, np->local_mac,
 407                                  send_skb->len) < 0) {
 408                 kfree_skb(send_skb);
 409                 return;
 410         }
 411
 412         /*
 413          * Fill out the arp protocol part.
 414          *
 415          * we only support ethernet device type,
 416          * which (according to RFC 1390) should always equal 1 (Ethernet).
 417          */
 418
 419         arp->ar_hrd = htons(np->dev->type);
 420         arp->ar_pro = htons(ETH_P_IP);
 421         arp->ar_hln = np->dev->addr_len;
 422         arp->ar_pln = 4;
 423         arp->ar_op = htons(type);
 424
 425         arp_ptr=(unsigned char *)(arp + 1);
 426         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 427         arp_ptr += np->dev->addr_len;
 428         memcpy(arp_ptr, &tip, 4);
 429         arp_ptr += 4;
 430         memcpy(arp_ptr, sha, np->dev->addr_len);
 431         arp_ptr += np->dev->addr_len;
 432         memcpy(arp_ptr, &sip, 4);
 433
 434         netpoll_send_skb(np, send_skb);
 435 }
 436
 437 int __netpoll_rx(struct sk_buff *skb)
 438 {
 439         int proto, len, ulen;
 440         struct iphdr *iph;
 441         struct udphdr *uh;
 442         struct netpoll_info *npi = skb->dev->npinfo;
 443         struct netpoll *np = npi->rx_np;
 444
 445         if (!np)
 446                 goto out;
 447         if (skb->dev->type != ARPHRD_ETHER)
 448                 goto out;
 449
 450         /* check if netpoll clients need ARP */
 451         if (skb->protocol == htons(ETH_P_ARP) &&
 452             atomic_read(&trapped)) {
 453                 skb_queue_tail(&npi->arp_tx, skb);
 454                 return 1;
 455         }
 456
 457         proto = ntohs(eth_hdr(skb)->h_proto);
 458         if (proto != ETH_P_IP)
 459                 goto out;
 460         if (skb->pkt_type == PACKET_OTHERHOST)
 461                 goto out;
 462         if (skb_shared(skb))
 463                 goto out;
 464
 465         iph = (struct iphdr *)skb->data;
 466         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 467                 goto out;
 468         if (iph->ihl < 5 || iph->version != 4)
 469                 goto out;
 470         if (!pskb_may_pull(skb, iph->ihl*4))
 471                 goto out;
 472         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 473                 goto out;
 474
 475         len = ntohs(iph->tot_len);
 476         if (skb->len < len || len < iph->ihl*4)
 477                 goto out;
 478
 479         /*
 480          * Our transport medium may have padded the buffer out.
 481          * Now We trim to the true length of the frame.
 482          */
 483         if (pskb_trim_rcsum(skb, len))
 484                 goto out;
 485
 486         if (iph->protocol != IPPROTO_UDP)
 487                 goto out;
 488
 489         len -= iph->ihl*4;
 490         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 491         ulen = ntohs(uh->len);
 492
 493         if (ulen != len)
 494                 goto out;
 495         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 496                 goto out;
 497         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 498                 goto out;
 499         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 500                 goto out;
 501         if (np->local_port && np->local_port != ntohs(uh->dest))
 502                 goto out;
 503
 504         np->rx_hook(np, ntohs(uh->source),
 505                     (char *)(uh+1),
 506                     ulen - sizeof(struct udphdr));
 507
 508         kfree_skb(skb);
 509         return 1;
 510
 511 out:
 512         if (atomic_read(&trapped)) {
 513                 kfree_skb(skb);
 514                 return 1;
 515         }
 516
 517         return 0;
 518 }
 519
 520 int netpoll_parse_options(struct netpoll *np, char *opt)
 521 {
 522         char *cur=opt, *delim;
 523
 524         if (*cur != '@') {
 525                 if ((delim = strchr(cur, '@')) == NULL)
 526                         goto parse_failed;
 527                 *delim = 0;
 528                 np->local_port = simple_strtol(cur, NULL, 10);
 529                 cur = delim;
 530         }
 531         cur++;
 532         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 533
 534         if (*cur != '/') {
 535                 if ((delim = strchr(cur, '/')) == NULL)
 536                         goto parse_failed;
 537                 *delim = 0;
 538                 np->local_ip = ntohl(in_aton(cur));
 539                 cur = delim;
 540
 541                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 542                        np->name, HIPQUAD(np->local_ip));
 543         }
 544         cur++;
 545
 546         if (*cur != ',') {
 547                 /* parse out dev name */
 548                 if ((delim = strchr(cur, ',')) == NULL)
 549                         goto parse_failed;
 550                 *delim = 0;
 551                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 552                 cur = delim;
 553         }
 554         cur++;
 555
 556         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 557
 558         if (*cur != '@') {
 559                 /* dst port */
 560                 if ((delim = strchr(cur, '@')) == NULL)
 561                         goto parse_failed;
 562                 *delim = 0;
 563                 np->remote_port = simple_strtol(cur, NULL, 10);
 564                 cur = delim;
 565         }
 566         cur++;
 567         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 568
 569         /* dst ip */
 570         if ((delim = strchr(cur, '/')) == NULL)
 571                 goto parse_failed;
 572         *delim = 0;
 573         np->remote_ip = ntohl(in_aton(cur));
 574         cur = delim + 1;
 575
 576         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 577                np->name, HIPQUAD(np->remote_ip));
 578
 579         if (*cur != 0) {
 580                 /* MAC address */
 581                 if ((delim = strchr(cur, ':')) == NULL)
 582                         goto parse_failed;
 583                 *delim = 0;
 584                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 585                 cur = delim + 1;
 586                 if ((delim = strchr(cur, ':')) == NULL)
 587                         goto parse_failed;
 588                 *delim = 0;
 589                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 590                 cur = delim + 1;
 591                 if ((delim = strchr(cur, ':')) == NULL)
 592                         goto parse_failed;
 593                 *delim = 0;
 594                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 595                 cur = delim + 1;
 596                 if ((delim = strchr(cur, ':')) == NULL)
 597                         goto parse_failed;
 598                 *delim = 0;
 599                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 600                 cur = delim + 1;
 601                 if ((delim = strchr(cur, ':')) == NULL)
 602                         goto parse_failed;
 603                 *delim = 0;
 604                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 605                 cur = delim + 1;
 606                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 607         }
 608
 609         printk(KERN_INFO "%s: remote ethernet address "
 610                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 611                np->name,
 612                np->remote_mac[0],
 613                np->remote_mac[1],
 614                np->remote_mac[2],
 615                np->remote_mac[3],
 616                np->remote_mac[4],
 617                np->remote_mac[5]);
 618
 619         return 0;
 620
 621  parse_failed:
 622         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 623                np->name, cur);
 624         return -1;
 625 }
 626
 627 int netpoll_setup(struct netpoll *np)
 628 {
 629         struct net_device *ndev = NULL;
 630         struct in_device *in_dev;
 631         struct netpoll_info *npinfo;
 632         unsigned long flags;
 633         int err;
 634
 635         if (np->dev_name)
 636                 ndev = dev_get_by_name(np->dev_name);
 637         if (!ndev) {
 638                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 639                        np->name, np->dev_name);
 640                 return -ENODEV;
 641         }
 642
 643         np->dev = ndev;
 644         if (!ndev->npinfo) {
 645                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 646                 if (!npinfo) {
 647                         err = -ENOMEM;
 648                         goto release;
 649                 }
 650
 651                 npinfo->rx_flags = 0;
 652                 npinfo->rx_np = NULL;
 653                 spin_lock_init(&npinfo->poll_lock);
 654                 npinfo->poll_owner = -1;
 655
 656                 spin_lock_init(&npinfo->rx_lock);
 657                 skb_queue_head_init(&npinfo->arp_tx);
 658                 skb_queue_head_init(&npinfo->txq);
 659                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 660
 661                 atomic_set(&npinfo->refcnt, 1);
 662         } else {
 663                 npinfo = ndev->npinfo;
 664                 atomic_inc(&npinfo->refcnt);
 665         }
 666
 667         if (!ndev->poll_controller) {
 668                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 669                        np->name, np->dev_name);
 670                 err = -ENOTSUPP;
 671                 goto release;
 672         }
 673
 674         if (!netif_running(ndev)) {
 675                 unsigned long atmost, atleast;
 676
 677                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 678                        np->name, np->dev_name);
 679
 680                 rtnl_lock();
 681                 err = dev_open(ndev);
 682                 rtnl_unlock();
 683
 684                 if (err) {
 685                         printk(KERN_ERR "%s: failed to open %s\n",
 686                                np->name, ndev->name);
 687                         goto release;
 688                 }
 689
 690                 atleast = jiffies + HZ/10;
 691                 atmost = jiffies + 4*HZ;
 692                 while (!netif_carrier_ok(ndev)) {
 693                         if (time_after(jiffies, atmost)) {
 694                                 printk(KERN_NOTICE
 695                                        "%s: timeout waiting for carrier\n",
 696                                        np->name);
 697                                 break;
 698                         }
 699                         cond_resched();
 700                 }
 701
 702                 /* If carrier appears to come up instantly, we don't
 703                  * trust it and pause so that we don't pump all our
 704                  * queued console messages into the bitbucket.
 705                  */
 706
 707                 if (time_before(jiffies, atleast)) {
 708                         printk(KERN_NOTICE "%s: carrier detect appears"
 709                                " untrustworthy, waiting 4 seconds\n",
 710                                np->name);
 711                         msleep(4000);
 712                 }
 713         }
 714
 715         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
 716                 memcpy(np->local_mac, ndev->dev_addr, 6);
 717
 718         if (!np->local_ip) {
 719                 rcu_read_lock();
 720                 in_dev = __in_dev_get_rcu(ndev);
 721
 722                 if (!in_dev || !in_dev->ifa_list) {
 723                         rcu_read_unlock();
 724                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 725                                np->name, np->dev_name);
 726                         err = -EDESTADDRREQ;
 727                         goto release;
 728                 }
 729
 730                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 731                 rcu_read_unlock();
 732                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 733                        np->name, HIPQUAD(np->local_ip));
 734         }
 735
 736         if (np->rx_hook) {
 737                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 738                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 739                 npinfo->rx_np = np;
 740                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 741         }
 742
 743         /* fill up the skb queue */
 744         refill_skbs();
 745
 746         /* last thing to do is link it to the net device structure */
 747         ndev->npinfo = npinfo;
 748
 749         /* avoid racing with NAPI reading npinfo */
 750         synchronize_rcu();
 751
 752         return 0;
 753
 754  release:
 755         if (!ndev->npinfo)
 756                 kfree(npinfo);
 757         np->dev = NULL;
 758         dev_put(ndev);
 759         return err;
 760 }
 761
 762 static int __init netpoll_init(void)
 763 {
 764         skb_queue_head_init(&skb_pool);
 765         return 0;
 766 }
 767 core_initcall(netpoll_init);
 768
 769 void netpoll_cleanup(struct netpoll *np)
 770 {
 771         struct netpoll_info *npinfo;
 772         unsigned long flags;
 773
 774         if (np->dev) {
 775                 npinfo = np->dev->npinfo;
 776                 if (npinfo) {
 777                         if (npinfo->rx_np == np) {
 778                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 779                                 npinfo->rx_np = NULL;
 780                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 781                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 782                         }
 783
 784                         np->dev->npinfo = NULL;
 785                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 786                                 skb_queue_purge(&npinfo->arp_tx);
 787                                 skb_queue_purge(&npinfo->txq);
 788                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 789                                 flush_scheduled_work();
 790
 791                                 kfree(npinfo);
 792                         }
 793                 }
 794
 795                 dev_put(np->dev);
 796         }
 797
 798         np->dev = NULL;
 799 }
 800
 801 int netpoll_trap(void)
 802 {
 803         return atomic_read(&trapped);
 804 }
 805
 806 void netpoll_set_trap(int trap)
 807 {
 808         if (trap)
 809                 atomic_inc(&trapped);
 810         else
 811                 atomic_dec(&trapped);
 812 }
 813
 814 EXPORT_SYMBOL(netpoll_set_trap);
 815 EXPORT_SYMBOL(netpoll_trap);
 816 EXPORT_SYMBOL(netpoll_parse_options);
 817 EXPORT_SYMBOL(netpoll_setup);
 818 EXPORT_SYMBOL(netpoll_cleanup);
 819 EXPORT_SYMBOL(netpoll_send_udp);
 820 EXPORT_SYMBOL(netpoll_poll);