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/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 DEFINE_SPINLOCK(skb_list_lock);
  38 static int nr_skbs;
  39 static struct sk_buff *skbs;
  40
  41 static DEFINE_SPINLOCK(queue_lock);
  42 static int queue_depth;
  43 static struct sk_buff *queue_head, *queue_tail;
  44
  45 static atomic_t trapped;
  46
  47 #define NETPOLL_RX_ENABLED  1
  48 #define NETPOLL_RX_DROP     2
  49
  50 #define MAX_SKB_SIZE \
  51                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  52                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  53
  54 static void zap_completion_queue(void);
  55
  56 static void queue_process(void *p)
  57 {
  58         unsigned long flags;
  59         struct sk_buff *skb;
  60
  61         while (queue_head) {
  62                 spin_lock_irqsave(&queue_lock, flags);
  63
  64                 skb = queue_head;
  65                 queue_head = skb->next;
  66                 if (skb == queue_tail)
  67                         queue_head = NULL;
  68
  69                 queue_depth--;
  70
  71                 spin_unlock_irqrestore(&queue_lock, flags);
  72
  73                 dev_queue_xmit(skb);
  74         }
  75 }
  76
  77 static DECLARE_WORK(send_queue, queue_process, NULL);
  78
  79 void netpoll_queue(struct sk_buff *skb)
  80 {
  81         unsigned long flags;
  82
  83         if (queue_depth == MAX_QUEUE_DEPTH) {
  84                 __kfree_skb(skb);
  85                 return;
  86         }
  87
  88         spin_lock_irqsave(&queue_lock, flags);
  89         if (!queue_head)
  90                 queue_head = skb;
  91         else
  92                 queue_tail->next = skb;
  93         queue_tail = skb;
  94         queue_depth++;
  95         spin_unlock_irqrestore(&queue_lock, flags);
  96
  97         schedule_work(&send_queue);
  98 }
  99
 100 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 101                              unsigned short ulen, u32 saddr, u32 daddr)
 102 {
 103         if (uh->check == 0)
 104                 return 0;
 105
 106         if (skb->ip_summed == CHECKSUM_HW)
 107                 return csum_tcpudp_magic(
 108                         saddr, daddr, ulen, IPPROTO_UDP, skb->csum);
 109
 110         skb->csum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 111
 112         return csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
 113 }
 114
 115 /*
 116  * Check whether delayed processing was scheduled for our NIC. If so,
 117  * we attempt to grab the poll lock and use ->poll() to pump the card.
 118  * If this fails, either we've recursed in ->poll() or it's already
 119  * running on another CPU.
 120  *
 121  * Note: we don't mask interrupts with this lock because we're using
 122  * trylock here and interrupts are already disabled in the softirq
 123  * case. Further, we test the poll_owner to avoid recursion on UP
 124  * systems where the lock doesn't exist.
 125  *
 126  * In cases where there is bi-directional communications, reading only
 127  * one message at a time can lead to packets being dropped by the
 128  * network adapter, forcing superfluous retries and possibly timeouts.
 129  * Thus, we set our budget to greater than 1.
 130  */
 131 static void poll_napi(struct netpoll *np)
 132 {
 133         int budget = 16;
 134
 135         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
 136             np->poll_owner != smp_processor_id() &&
 137             spin_trylock(&np->poll_lock)) {
 138                 np->rx_flags |= NETPOLL_RX_DROP;
 139                 atomic_inc(&trapped);
 140
 141                 np->dev->poll(np->dev, &budget);
 142
 143                 atomic_dec(&trapped);
 144                 np->rx_flags &= ~NETPOLL_RX_DROP;
 145                 spin_unlock(&np->poll_lock);
 146         }
 147 }
 148
 149 void netpoll_poll(struct netpoll *np)
 150 {
 151         if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
 152                 return;
 153
 154         /* Process pending work on NIC */
 155         np->dev->poll_controller(np->dev);
 156         if (np->dev->poll)
 157                 poll_napi(np);
 158
 159         zap_completion_queue();
 160 }
 161
 162 static void refill_skbs(void)
 163 {
 164         struct sk_buff *skb;
 165         unsigned long flags;
 166
 167         spin_lock_irqsave(&skb_list_lock, flags);
 168         while (nr_skbs < MAX_SKBS) {
 169                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 170                 if (!skb)
 171                         break;
 172
 173                 skb->next = skbs;
 174                 skbs = skb;
 175                 nr_skbs++;
 176         }
 177         spin_unlock_irqrestore(&skb_list_lock, flags);
 178 }
 179
 180 static void zap_completion_queue(void)
 181 {
 182         unsigned long flags;
 183         struct softnet_data *sd = &get_cpu_var(softnet_data);
 184
 185         if (sd->completion_queue) {
 186                 struct sk_buff *clist;
 187
 188                 local_irq_save(flags);
 189                 clist = sd->completion_queue;
 190                 sd->completion_queue = NULL;
 191                 local_irq_restore(flags);
 192
 193                 while (clist != NULL) {
 194                         struct sk_buff *skb = clist;
 195                         clist = clist->next;
 196                         if(skb->destructor)
 197                                 dev_kfree_skb_any(skb); /* put this one back */
 198                         else
 199                                 __kfree_skb(skb);
 200                 }
 201         }
 202
 203         put_cpu_var(softnet_data);
 204 }
 205
 206 static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
 207 {
 208         int once = 1, count = 0;
 209         unsigned long flags;
 210         struct sk_buff *skb = NULL;
 211
 212         zap_completion_queue();
 213 repeat:
 214         if (nr_skbs < MAX_SKBS)
 215                 refill_skbs();
 216
 217         skb = alloc_skb(len, GFP_ATOMIC);
 218
 219         if (!skb) {
 220                 spin_lock_irqsave(&skb_list_lock, flags);
 221                 skb = skbs;
 222                 if (skb) {
 223                         skbs = skb->next;
 224                         skb->next = NULL;
 225                         nr_skbs--;
 226                 }
 227                 spin_unlock_irqrestore(&skb_list_lock, flags);
 228         }
 229
 230         if(!skb) {
 231                 count++;
 232                 if (once && (count == 1000000)) {
 233                         printk("out of netpoll skbs!\n");
 234                         once = 0;
 235                 }
 236                 netpoll_poll(np);
 237                 goto repeat;
 238         }
 239
 240         atomic_set(&skb->users, 1);
 241         skb_reserve(skb, reserve);
 242         return skb;
 243 }
 244
 245 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 246 {
 247         int status;
 248
 249 repeat:
 250         if(!np || !np->dev || !netif_running(np->dev)) {
 251                 __kfree_skb(skb);
 252                 return;
 253         }
 254
 255         /* avoid recursion */
 256         if(np->poll_owner == smp_processor_id() ||
 257            np->dev->xmit_lock_owner == smp_processor_id()) {
 258                 if (np->drop)
 259                         np->drop(skb);
 260                 else
 261                         __kfree_skb(skb);
 262                 return;
 263         }
 264
 265         spin_lock(&np->dev->xmit_lock);
 266         np->dev->xmit_lock_owner = smp_processor_id();
 267
 268         /*
 269          * network drivers do not expect to be called if the queue is
 270          * stopped.
 271          */
 272         if (netif_queue_stopped(np->dev)) {
 273                 np->dev->xmit_lock_owner = -1;
 274                 spin_unlock(&np->dev->xmit_lock);
 275
 276                 netpoll_poll(np);
 277                 goto repeat;
 278         }
 279
 280         status = np->dev->hard_start_xmit(skb, np->dev);
 281         np->dev->xmit_lock_owner = -1;
 282         spin_unlock(&np->dev->xmit_lock);
 283
 284         /* transmit busy */
 285         if(status) {
 286                 netpoll_poll(np);
 287                 goto repeat;
 288         }
 289 }
 290
 291 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 292 {
 293         int total_len, eth_len, ip_len, udp_len;
 294         struct sk_buff *skb;
 295         struct udphdr *udph;
 296         struct iphdr *iph;
 297         struct ethhdr *eth;
 298
 299         udp_len = len + sizeof(*udph);
 300         ip_len = eth_len = udp_len + sizeof(*iph);
 301         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 302
 303         skb = find_skb(np, total_len, total_len - len);
 304         if (!skb)
 305                 return;
 306
 307         memcpy(skb->data, msg, len);
 308         skb->len += len;
 309
 310         udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 311         udph->source = htons(np->local_port);
 312         udph->dest = htons(np->remote_port);
 313         udph->len = htons(udp_len);
 314         udph->check = 0;
 315
 316         iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 317
 318         /* iph->version = 4; iph->ihl = 5; */
 319         put_unaligned(0x45, (unsigned char *)iph);
 320         iph->tos      = 0;
 321         put_unaligned(htons(ip_len), &(iph->tot_len));
 322         iph->id       = 0;
 323         iph->frag_off = 0;
 324         iph->ttl      = 64;
 325         iph->protocol = IPPROTO_UDP;
 326         iph->check    = 0;
 327         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 328         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 329         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 330
 331         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 332
 333         eth->h_proto = htons(ETH_P_IP);
 334         memcpy(eth->h_source, np->local_mac, 6);
 335         memcpy(eth->h_dest, np->remote_mac, 6);
 336
 337         skb->dev = np->dev;
 338
 339         netpoll_send_skb(np, skb);
 340 }
 341
 342 static void arp_reply(struct sk_buff *skb)
 343 {
 344         struct arphdr *arp;
 345         unsigned char *arp_ptr;
 346         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 347         u32 sip, tip;
 348         struct sk_buff *send_skb;
 349         struct netpoll *np = skb->dev->np;
 350
 351         if (!np) return;
 352
 353         /* No arp on this interface */
 354         if (skb->dev->flags & IFF_NOARP)
 355                 return;
 356
 357         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
 358                                  (2 * skb->dev->addr_len) +
 359                                  (2 * sizeof(u32)))))
 360                 return;
 361
 362         skb->h.raw = skb->nh.raw = skb->data;
 363         arp = skb->nh.arph;
 364
 365         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 366              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 367             arp->ar_pro != htons(ETH_P_IP) ||
 368             arp->ar_op != htons(ARPOP_REQUEST))
 369                 return;
 370
 371         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
 372         memcpy(&sip, arp_ptr, 4);
 373         arp_ptr += 4 + skb->dev->addr_len;
 374         memcpy(&tip, arp_ptr, 4);
 375
 376         /* Should we ignore arp? */
 377         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
 378                 return;
 379
 380         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
 381         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
 382                             LL_RESERVED_SPACE(np->dev));
 383
 384         if (!send_skb)
 385                 return;
 386
 387         send_skb->nh.raw = send_skb->data;
 388         arp = (struct arphdr *) skb_put(send_skb, size);
 389         send_skb->dev = skb->dev;
 390         send_skb->protocol = htons(ETH_P_ARP);
 391
 392         /* Fill the device header for the ARP frame */
 393
 394         if (np->dev->hard_header &&
 395             np->dev->hard_header(send_skb, skb->dev, ptype,
 396                                        np->remote_mac, np->local_mac,
 397                                        send_skb->len) < 0) {
 398                 kfree_skb(send_skb);
 399                 return;
 400         }
 401
 402         /*
 403          * Fill out the arp protocol part.
 404          *
 405          * we only support ethernet device type,
 406          * which (according to RFC 1390) should always equal 1 (Ethernet).
 407          */
 408
 409         arp->ar_hrd = htons(np->dev->type);
 410         arp->ar_pro = htons(ETH_P_IP);
 411         arp->ar_hln = np->dev->addr_len;
 412         arp->ar_pln = 4;
 413         arp->ar_op = htons(type);
 414
 415         arp_ptr=(unsigned char *)(arp + 1);
 416         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 417         arp_ptr += np->dev->addr_len;
 418         memcpy(arp_ptr, &tip, 4);
 419         arp_ptr += 4;
 420         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
 421         arp_ptr += np->dev->addr_len;
 422         memcpy(arp_ptr, &sip, 4);
 423
 424         netpoll_send_skb(np, send_skb);
 425 }
 426
 427 int __netpoll_rx(struct sk_buff *skb)
 428 {
 429         int proto, len, ulen;
 430         struct iphdr *iph;
 431         struct udphdr *uh;
 432         struct netpoll *np = skb->dev->np;
 433
 434         if (!np->rx_hook)
 435                 goto out;
 436         if (skb->dev->type != ARPHRD_ETHER)
 437                 goto out;
 438
 439         /* check if netpoll clients need ARP */
 440         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
 441             atomic_read(&trapped)) {
 442                 arp_reply(skb);
 443                 return 1;
 444         }
 445
 446         proto = ntohs(eth_hdr(skb)->h_proto);
 447         if (proto != ETH_P_IP)
 448                 goto out;
 449         if (skb->pkt_type == PACKET_OTHERHOST)
 450                 goto out;
 451         if (skb_shared(skb))
 452                 goto out;
 453
 454         iph = (struct iphdr *)skb->data;
 455         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 456                 goto out;
 457         if (iph->ihl < 5 || iph->version != 4)
 458                 goto out;
 459         if (!pskb_may_pull(skb, iph->ihl*4))
 460                 goto out;
 461         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 462                 goto out;
 463
 464         len = ntohs(iph->tot_len);
 465         if (skb->len < len || len < iph->ihl*4)
 466                 goto out;
 467
 468         if (iph->protocol != IPPROTO_UDP)
 469                 goto out;
 470
 471         len -= iph->ihl*4;
 472         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 473         ulen = ntohs(uh->len);
 474
 475         if (ulen != len)
 476                 goto out;
 477         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr) < 0)
 478                 goto out;
 479         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 480                 goto out;
 481         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 482                 goto out;
 483         if (np->local_port && np->local_port != ntohs(uh->dest))
 484                 goto out;
 485
 486         np->rx_hook(np, ntohs(uh->source),
 487                     (char *)(uh+1),
 488                     ulen - sizeof(struct udphdr));
 489
 490         kfree_skb(skb);
 491         return 1;
 492
 493 out:
 494         if (atomic_read(&trapped)) {
 495                 kfree_skb(skb);
 496                 return 1;
 497         }
 498
 499         return 0;
 500 }
 501
 502 int netpoll_parse_options(struct netpoll *np, char *opt)
 503 {
 504         char *cur=opt, *delim;
 505
 506         if(*cur != '@') {
 507                 if ((delim = strchr(cur, '@')) == NULL)
 508                         goto parse_failed;
 509                 *delim=0;
 510                 np->local_port=simple_strtol(cur, NULL, 10);
 511                 cur=delim;
 512         }
 513         cur++;
 514         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
 515
 516         if(*cur != '/') {
 517                 if ((delim = strchr(cur, '/')) == NULL)
 518                         goto parse_failed;
 519                 *delim=0;
 520                 np->local_ip=ntohl(in_aton(cur));
 521                 cur=delim;
 522
 523                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 524                        np->name, HIPQUAD(np->local_ip));
 525         }
 526         cur++;
 527
 528         if ( *cur != ',') {
 529                 /* parse out dev name */
 530                 if ((delim = strchr(cur, ',')) == NULL)
 531                         goto parse_failed;
 532                 *delim=0;
 533                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 534                 cur=delim;
 535         }
 536         cur++;
 537
 538         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
 539
 540         if ( *cur != '@' ) {
 541                 /* dst port */
 542                 if ((delim = strchr(cur, '@')) == NULL)
 543                         goto parse_failed;
 544                 *delim=0;
 545                 np->remote_port=simple_strtol(cur, NULL, 10);
 546                 cur=delim;
 547         }
 548         cur++;
 549         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
 550
 551         /* dst ip */
 552         if ((delim = strchr(cur, '/')) == NULL)
 553                 goto parse_failed;
 554         *delim=0;
 555         np->remote_ip=ntohl(in_aton(cur));
 556         cur=delim+1;
 557
 558         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 559                        np->name, HIPQUAD(np->remote_ip));
 560
 561         if( *cur != 0 )
 562         {
 563                 /* MAC address */
 564                 if ((delim = strchr(cur, ':')) == NULL)
 565                         goto parse_failed;
 566                 *delim=0;
 567                 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
 568                 cur=delim+1;
 569                 if ((delim = strchr(cur, ':')) == NULL)
 570                         goto parse_failed;
 571                 *delim=0;
 572                 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
 573                 cur=delim+1;
 574                 if ((delim = strchr(cur, ':')) == NULL)
 575                         goto parse_failed;
 576                 *delim=0;
 577                 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
 578                 cur=delim+1;
 579                 if ((delim = strchr(cur, ':')) == NULL)
 580                         goto parse_failed;
 581                 *delim=0;
 582                 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
 583                 cur=delim+1;
 584                 if ((delim = strchr(cur, ':')) == NULL)
 585                         goto parse_failed;
 586                 *delim=0;
 587                 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
 588                 cur=delim+1;
 589                 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
 590         }
 591
 592         printk(KERN_INFO "%s: remote ethernet address "
 593                "%02x:%02x:%02x:%02x:%02x:%02x\n",
 594                np->name,
 595                np->remote_mac[0],
 596                np->remote_mac[1],
 597                np->remote_mac[2],
 598                np->remote_mac[3],
 599                np->remote_mac[4],
 600                np->remote_mac[5]);
 601
 602         return 0;
 603
 604  parse_failed:
 605         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 606                np->name, cur);
 607         return -1;
 608 }
 609
 610 int netpoll_setup(struct netpoll *np)
 611 {
 612         struct net_device *ndev = NULL;
 613         struct in_device *in_dev;
 614
 615         np->poll_lock = SPIN_LOCK_UNLOCKED;
 616         np->poll_owner = -1;
 617
 618         if (np->dev_name)
 619                 ndev = dev_get_by_name(np->dev_name);
 620         if (!ndev) {
 621                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 622                        np->name, np->dev_name);
 623                 return -1;
 624         }
 625
 626         np->dev = ndev;
 627         ndev->np = np;
 628
 629         if (!ndev->poll_controller) {
 630                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 631                        np->name, np->dev_name);
 632                 goto release;
 633         }
 634
 635         if (!netif_running(ndev)) {
 636                 unsigned long atmost, atleast;
 637
 638                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 639                        np->name, np->dev_name);
 640
 641                 rtnl_shlock();
 642                 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
 643                         printk(KERN_ERR "%s: failed to open %s\n",
 644                                np->name, np->dev_name);
 645                         rtnl_shunlock();
 646                         goto release;
 647                 }
 648                 rtnl_shunlock();
 649
 650                 atleast = jiffies + HZ/10;
 651                 atmost = jiffies + 4*HZ;
 652                 while (!netif_carrier_ok(ndev)) {
 653                         if (time_after(jiffies, atmost)) {
 654                                 printk(KERN_NOTICE
 655                                        "%s: timeout waiting for carrier\n",
 656                                        np->name);
 657                                 break;
 658                         }
 659                         cond_resched();
 660                 }
 661
 662                 /* If carrier appears to come up instantly, we don't
 663                  * trust it and pause so that we don't pump all our
 664                  * queued console messages into the bitbucket.
 665                  */
 666
 667                 if (time_before(jiffies, atleast)) {
 668                         printk(KERN_NOTICE "%s: carrier detect appears"
 669                                " untrustworthy, waiting 4 seconds\n",
 670                                np->name);
 671                         msleep(4000);
 672                 }
 673         }
 674
 675         if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
 676                 memcpy(np->local_mac, ndev->dev_addr, 6);
 677
 678         if (!np->local_ip) {
 679                 rcu_read_lock();
 680                 in_dev = __in_dev_get(ndev);
 681
 682                 if (!in_dev || !in_dev->ifa_list) {
 683                         rcu_read_unlock();
 684                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 685                                np->name, np->dev_name);
 686                         goto release;
 687                 }
 688
 689                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 690                 rcu_read_unlock();
 691                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 692                        np->name, HIPQUAD(np->local_ip));
 693         }
 694
 695         if(np->rx_hook)
 696                 np->rx_flags = NETPOLL_RX_ENABLED;
 697
 698         return 0;
 699
 700  release:
 701         ndev->np = NULL;
 702         np->dev = NULL;
 703         dev_put(ndev);
 704         return -1;
 705 }
 706
 707 void netpoll_cleanup(struct netpoll *np)
 708 {
 709         if (np->dev)
 710                 np->dev->np = NULL;
 711         dev_put(np->dev);
 712         np->dev = NULL;
 713 }
 714
 715 int netpoll_trap(void)
 716 {
 717         return atomic_read(&trapped);
 718 }
 719
 720 void netpoll_set_trap(int trap)
 721 {
 722         if (trap)
 723                 atomic_inc(&trapped);
 724         else
 725                 atomic_dec(&trapped);
 726 }
 727
 728 EXPORT_SYMBOL(netpoll_set_trap);
 729 EXPORT_SYMBOL(netpoll_trap);
 730 EXPORT_SYMBOL(netpoll_parse_options);
 731 EXPORT_SYMBOL(netpoll_setup);
 732 EXPORT_SYMBOL(netpoll_cleanup);
 733 EXPORT_SYMBOL(netpoll_send_udp);
 734 EXPORT_SYMBOL(netpoll_poll);
 735 EXPORT_SYMBOL(netpoll_queue);