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/moduleparam.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 <linux/slab.h>
  26 #include <net/tcp.h>
  27 #include <net/udp.h>
  28 #include <asm/unaligned.h>
  29 #include <trace/events/napi.h>
  30
  31 /*
  32  * We maintain a small pool of fully-sized skbs, to make sure the
  33  * message gets out even in extreme OOM situations.
  34  */
  35
  36 #define MAX_UDP_CHUNK 1460
  37 #define MAX_SKBS 32
  38 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
  39
  40 static struct sk_buff_head skb_pool;
  41
  42 static atomic_t trapped;
  43
  44 #define USEC_PER_POLL   50
  45 #define NETPOLL_RX_ENABLED  1
  46 #define NETPOLL_RX_DROP     2
  47
  48 #define MAX_SKB_SIZE \
  49                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  50                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  51
  52 static void arp_reply(struct sk_buff *skb);
  53
  54 static unsigned int carrier_timeout = 4;
  55 module_param(carrier_timeout, uint, 0644);
  56
  57 static void queue_process(struct work_struct *work)
  58 {
  59         struct netpoll_info *npinfo =
  60                 container_of(work, struct netpoll_info, tx_work.work);
  61         struct sk_buff *skb;
  62         unsigned long flags;
  63
  64         while ((skb = skb_dequeue(&npinfo->txq))) {
  65                 struct net_device *dev = skb->dev;
  66                 const struct net_device_ops *ops = dev->netdev_ops;
  67                 struct netdev_queue *txq;
  68
  69                 if (!netif_device_present(dev) || !netif_running(dev)) {
  70                         __kfree_skb(skb);
  71                         continue;
  72                 }
  73
  74                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  75
  76                 local_irq_save(flags);
  77                 __netif_tx_lock(txq, smp_processor_id());
  78                 if (netif_tx_queue_stopped(txq) ||
  79                     netif_tx_queue_frozen(txq) ||
  80                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  81                         skb_queue_head(&npinfo->txq, skb);
  82                         __netif_tx_unlock(txq);
  83                         local_irq_restore(flags);
  84
  85                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  86                         return;
  87                 }
  88                 __netif_tx_unlock(txq);
  89                 local_irq_restore(flags);
  90         }
  91 }
  92
  93 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  94                             unsigned short ulen, __be32 saddr, __be32 daddr)
  95 {
  96         __wsum psum;
  97
  98         if (uh->check == 0 || skb_csum_unnecessary(skb))
  99                 return 0;
 100
 101         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 102
 103         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 104             !csum_fold(csum_add(psum, skb->csum)))
 105                 return 0;
 106
 107         skb->csum = psum;
 108
 109         return __skb_checksum_complete(skb);
 110 }
 111
 112 /*
 113  * Check whether delayed processing was scheduled for our NIC. If so,
 114  * we attempt to grab the poll lock and use ->poll() to pump the card.
 115  * If this fails, either we've recursed in ->poll() or it's already
 116  * running on another CPU.
 117  *
 118  * Note: we don't mask interrupts with this lock because we're using
 119  * trylock here and interrupts are already disabled in the softirq
 120  * case. Further, we test the poll_owner to avoid recursion on UP
 121  * systems where the lock doesn't exist.
 122  *
 123  * In cases where there is bi-directional communications, reading only
 124  * one message at a time can lead to packets being dropped by the
 125  * network adapter, forcing superfluous retries and possibly timeouts.
 126  * Thus, we set our budget to greater than 1.
 127  */
 128 static int poll_one_napi(struct netpoll_info *npinfo,
 129                          struct napi_struct *napi, int budget)
 130 {
 131         int work;
 132
 133         /* net_rx_action's ->poll() invocations and our's are
 134          * synchronized by this test which is only made while
 135          * holding the napi->poll_lock.
 136          */
 137         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 138                 return budget;
 139
 140         npinfo->rx_flags |= NETPOLL_RX_DROP;
 141         atomic_inc(&trapped);
 142         set_bit(NAPI_STATE_NPSVC, &napi->state);
 143
 144         work = napi->poll(napi, budget);
 145         trace_napi_poll(napi);
 146
 147         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 148         atomic_dec(&trapped);
 149         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 150
 151         return budget - work;
 152 }
 153
 154 static void poll_napi(struct net_device *dev)
 155 {
 156         struct napi_struct *napi;
 157         int budget = 16;
 158
 159         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 160                 if (napi->poll_owner != smp_processor_id() &&
 161                     spin_trylock(&napi->poll_lock)) {
 162                         budget = poll_one_napi(dev->npinfo, napi, budget);
 163                         spin_unlock(&napi->poll_lock);
 164
 165                         if (!budget)
 166                                 break;
 167                 }
 168         }
 169 }
 170
 171 static void service_arp_queue(struct netpoll_info *npi)
 172 {
 173         if (npi) {
 174                 struct sk_buff *skb;
 175
 176                 while ((skb = skb_dequeue(&npi->arp_tx)))
 177                         arp_reply(skb);
 178         }
 179 }
 180
 181 void netpoll_poll_dev(struct net_device *dev)
 182 {
 183         const struct net_device_ops *ops;
 184
 185         if (!dev || !netif_running(dev))
 186                 return;
 187
 188         ops = dev->netdev_ops;
 189         if (!ops->ndo_poll_controller)
 190                 return;
 191
 192         /* Process pending work on NIC */
 193         ops->ndo_poll_controller(dev);
 194
 195         poll_napi(dev);
 196
 197         service_arp_queue(dev->npinfo);
 198
 199 }
 200
 201 void netpoll_poll(struct netpoll *np)
 202 {
 203         netpoll_poll_dev(np->dev);
 204 }
 205
 206 static void refill_skbs(void)
 207 {
 208         struct sk_buff *skb;
 209         unsigned long flags;
 210
 211         spin_lock_irqsave(&skb_pool.lock, flags);
 212         while (skb_pool.qlen < MAX_SKBS) {
 213                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 214                 if (!skb)
 215                         break;
 216
 217                 __skb_queue_tail(&skb_pool, skb);
 218         }
 219         spin_unlock_irqrestore(&skb_pool.lock, flags);
 220 }
 221
 222 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 223 {
 224         int count = 0;
 225         struct sk_buff *skb;
 226
 227         refill_skbs();
 228 repeat:
 229
 230         skb = alloc_skb(len, GFP_ATOMIC);
 231         if (!skb)
 232                 skb = skb_dequeue(&skb_pool);
 233
 234         if (!skb) {
 235                 if (++count < 10) {
 236                         netpoll_poll(np);
 237                         goto repeat;
 238                 }
 239                 return NULL;
 240         }
 241
 242         atomic_set(&skb->users, 1);
 243         skb_reserve(skb, reserve);
 244         return skb;
 245 }
 246
 247 static int netpoll_owner_active(struct net_device *dev)
 248 {
 249         struct napi_struct *napi;
 250
 251         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 252                 if (napi->poll_owner == smp_processor_id())
 253                         return 1;
 254         }
 255         return 0;
 256 }
 257
 258 void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 259 {
 260         int status = NETDEV_TX_BUSY;
 261         unsigned long tries;
 262         struct net_device *dev = np->dev;
 263         const struct net_device_ops *ops = dev->netdev_ops;
 264         /* It is up to the caller to keep npinfo alive. */
 265         struct netpoll_info *npinfo = np->dev->npinfo;
 266
 267         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 268                 __kfree_skb(skb);
 269                 return;
 270         }
 271
 272         /* don't get messages out of order, and no recursion */
 273         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 274                 struct netdev_queue *txq;
 275                 unsigned long flags;
 276
 277                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 278
 279                 local_irq_save(flags);
 280                 /* try until next clock tick */
 281                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 282                      tries > 0; --tries) {
 283                         if (__netif_tx_trylock(txq)) {
 284                                 if (!netif_tx_queue_stopped(txq)) {
 285                                         dev->priv_flags |= IFF_IN_NETPOLL;
 286                                         status = ops->ndo_start_xmit(skb, dev);
 287                                         dev->priv_flags &= ~IFF_IN_NETPOLL;
 288                                         if (status == NETDEV_TX_OK)
 289                                                 txq_trans_update(txq);
 290                                 }
 291                                 __netif_tx_unlock(txq);
 292
 293                                 if (status == NETDEV_TX_OK)
 294                                         break;
 295
 296                         }
 297
 298                         /* tickle device maybe there is some cleanup */
 299                         netpoll_poll(np);
 300
 301                         udelay(USEC_PER_POLL);
 302                 }
 303
 304                 WARN_ONCE(!irqs_disabled(),
 305                         "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
 306                         dev->name, ops->ndo_start_xmit);
 307
 308                 local_irq_restore(flags);
 309         }
 310
 311         if (status != NETDEV_TX_OK) {
 312                 skb_queue_tail(&npinfo->txq, skb);
 313                 schedule_delayed_work(&npinfo->tx_work,0);
 314         }
 315 }
 316
 317 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 318 {
 319         int total_len, eth_len, ip_len, udp_len;
 320         struct sk_buff *skb;
 321         struct udphdr *udph;
 322         struct iphdr *iph;
 323         struct ethhdr *eth;
 324
 325         udp_len = len + sizeof(*udph);
 326         ip_len = eth_len = udp_len + sizeof(*iph);
 327         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 328
 329         skb = find_skb(np, total_len, total_len - len);
 330         if (!skb)
 331                 return;
 332
 333         skb_copy_to_linear_data(skb, msg, len);
 334         skb->len += len;
 335
 336         skb_push(skb, sizeof(*udph));
 337         skb_reset_transport_header(skb);
 338         udph = udp_hdr(skb);
 339         udph->source = htons(np->local_port);
 340         udph->dest = htons(np->remote_port);
 341         udph->len = htons(udp_len);
 342         udph->check = 0;
 343         udph->check = csum_tcpudp_magic(np->local_ip,
 344                                         np->remote_ip,
 345                                         udp_len, IPPROTO_UDP,
 346                                         csum_partial(udph, udp_len, 0));
 347         if (udph->check == 0)
 348                 udph->check = CSUM_MANGLED_0;
 349
 350         skb_push(skb, sizeof(*iph));
 351         skb_reset_network_header(skb);
 352         iph = ip_hdr(skb);
 353
 354         /* iph->version = 4; iph->ihl = 5; */
 355         put_unaligned(0x45, (unsigned char *)iph);
 356         iph->tos      = 0;
 357         put_unaligned(htons(ip_len), &(iph->tot_len));
 358         iph->id       = 0;
 359         iph->frag_off = 0;
 360         iph->ttl      = 64;
 361         iph->protocol = IPPROTO_UDP;
 362         iph->check    = 0;
 363         put_unaligned(np->local_ip, &(iph->saddr));
 364         put_unaligned(np->remote_ip, &(iph->daddr));
 365         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 366
 367         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 368         skb_reset_mac_header(skb);
 369         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 370         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 371         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 372
 373         skb->dev = np->dev;
 374
 375         netpoll_send_skb(np, skb);
 376 }
 377
 378 static void arp_reply(struct sk_buff *skb)
 379 {
 380         struct netpoll_info *npinfo = skb->dev->npinfo;
 381         struct arphdr *arp;
 382         unsigned char *arp_ptr;
 383         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 384         __be32 sip, tip;
 385         unsigned char *sha;
 386         struct sk_buff *send_skb;
 387         struct netpoll *np, *tmp;
 388         unsigned long flags;
 389         int hits = 0;
 390
 391         if (list_empty(&npinfo->rx_np))
 392                 return;
 393
 394         /* Before checking the packet, we do some early
 395            inspection whether this is interesting at all */
 396         spin_lock_irqsave(&npinfo->rx_lock, flags);
 397         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 398                 if (np->dev == skb->dev)
 399                         hits++;
 400         }
 401         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 402
 403         /* No netpoll struct is using this dev */
 404         if (!hits)
 405                 return;
 406
 407         /* No arp on this interface */
 408         if (skb->dev->flags & IFF_NOARP)
 409                 return;
 410
 411         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 412                 return;
 413
 414         skb_reset_network_header(skb);
 415         skb_reset_transport_header(skb);
 416         arp = arp_hdr(skb);
 417
 418         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 419              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 420             arp->ar_pro != htons(ETH_P_IP) ||
 421             arp->ar_op != htons(ARPOP_REQUEST))
 422                 return;
 423
 424         arp_ptr = (unsigned char *)(arp+1);
 425         /* save the location of the src hw addr */
 426         sha = arp_ptr;
 427         arp_ptr += skb->dev->addr_len;
 428         memcpy(&sip, arp_ptr, 4);
 429         arp_ptr += 4;
 430         /* If we actually cared about dst hw addr,
 431            it would get copied here */
 432         arp_ptr += skb->dev->addr_len;
 433         memcpy(&tip, arp_ptr, 4);
 434
 435         /* Should we ignore arp? */
 436         if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 437                 return;
 438
 439         size = arp_hdr_len(skb->dev);
 440
 441         spin_lock_irqsave(&npinfo->rx_lock, flags);
 442         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 443                 if (tip != np->local_ip)
 444                         continue;
 445
 446                 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 447                                     LL_RESERVED_SPACE(np->dev));
 448                 if (!send_skb)
 449                         continue;
 450
 451                 skb_reset_network_header(send_skb);
 452                 arp = (struct arphdr *) skb_put(send_skb, size);
 453                 send_skb->dev = skb->dev;
 454                 send_skb->protocol = htons(ETH_P_ARP);
 455
 456                 /* Fill the device header for the ARP frame */
 457                 if (dev_hard_header(send_skb, skb->dev, ptype,
 458                                     sha, np->dev->dev_addr,
 459                                     send_skb->len) < 0) {
 460                         kfree_skb(send_skb);
 461                         continue;
 462                 }
 463
 464                 /*
 465                  * Fill out the arp protocol part.
 466                  *
 467                  * we only support ethernet device type,
 468                  * which (according to RFC 1390) should
 469                  * always equal 1 (Ethernet).
 470                  */
 471
 472                 arp->ar_hrd = htons(np->dev->type);
 473                 arp->ar_pro = htons(ETH_P_IP);
 474                 arp->ar_hln = np->dev->addr_len;
 475                 arp->ar_pln = 4;
 476                 arp->ar_op = htons(type);
 477
 478                 arp_ptr = (unsigned char *)(arp + 1);
 479                 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 480                 arp_ptr += np->dev->addr_len;
 481                 memcpy(arp_ptr, &tip, 4);
 482                 arp_ptr += 4;
 483                 memcpy(arp_ptr, sha, np->dev->addr_len);
 484                 arp_ptr += np->dev->addr_len;
 485                 memcpy(arp_ptr, &sip, 4);
 486
 487                 netpoll_send_skb(np, send_skb);
 488
 489                 /* If there are several rx_hooks for the same address,
 490                    we're fine by sending a single reply */
 491                 break;
 492         }
 493         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 494 }
 495
 496 int __netpoll_rx(struct sk_buff *skb)
 497 {
 498         int proto, len, ulen;
 499         int hits = 0;
 500         struct iphdr *iph;
 501         struct udphdr *uh;
 502         struct netpoll_info *npinfo = skb->dev->npinfo;
 503         struct netpoll *np, *tmp;
 504
 505         if (list_empty(&npinfo->rx_np))
 506                 goto out;
 507
 508         if (skb->dev->type != ARPHRD_ETHER)
 509                 goto out;
 510
 511         /* check if netpoll clients need ARP */
 512         if (skb->protocol == htons(ETH_P_ARP) &&
 513             atomic_read(&trapped)) {
 514                 skb_queue_tail(&npinfo->arp_tx, skb);
 515                 return 1;
 516         }
 517
 518         proto = ntohs(eth_hdr(skb)->h_proto);
 519         if (proto != ETH_P_IP)
 520                 goto out;
 521         if (skb->pkt_type == PACKET_OTHERHOST)
 522                 goto out;
 523         if (skb_shared(skb))
 524                 goto out;
 525
 526         iph = (struct iphdr *)skb->data;
 527         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 528                 goto out;
 529         if (iph->ihl < 5 || iph->version != 4)
 530                 goto out;
 531         if (!pskb_may_pull(skb, iph->ihl*4))
 532                 goto out;
 533         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 534                 goto out;
 535
 536         len = ntohs(iph->tot_len);
 537         if (skb->len < len || len < iph->ihl*4)
 538                 goto out;
 539
 540         /*
 541          * Our transport medium may have padded the buffer out.
 542          * Now We trim to the true length of the frame.
 543          */
 544         if (pskb_trim_rcsum(skb, len))
 545                 goto out;
 546
 547         if (iph->protocol != IPPROTO_UDP)
 548                 goto out;
 549
 550         len -= iph->ihl*4;
 551         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 552         ulen = ntohs(uh->len);
 553
 554         if (ulen != len)
 555                 goto out;
 556         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 557                 goto out;
 558
 559         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 560                 if (np->local_ip && np->local_ip != iph->daddr)
 561                         continue;
 562                 if (np->remote_ip && np->remote_ip != iph->saddr)
 563                         continue;
 564                 if (np->local_port && np->local_port != ntohs(uh->dest))
 565                         continue;
 566
 567                 np->rx_hook(np, ntohs(uh->source),
 568                                (char *)(uh+1),
 569                                ulen - sizeof(struct udphdr));
 570                 hits++;
 571         }
 572
 573         if (!hits)
 574                 goto out;
 575
 576         kfree_skb(skb);
 577         return 1;
 578
 579 out:
 580         if (atomic_read(&trapped)) {
 581                 kfree_skb(skb);
 582                 return 1;
 583         }
 584
 585         return 0;
 586 }
 587
 588 void netpoll_print_options(struct netpoll *np)
 589 {
 590         printk(KERN_INFO "%s: local port %d\n",
 591                          np->name, np->local_port);
 592         printk(KERN_INFO "%s: local IP %pI4\n",
 593                          np->name, &np->local_ip);
 594         printk(KERN_INFO "%s: interface '%s'\n",
 595                          np->name, np->dev_name);
 596         printk(KERN_INFO "%s: remote port %d\n",
 597                          np->name, np->remote_port);
 598         printk(KERN_INFO "%s: remote IP %pI4\n",
 599                          np->name, &np->remote_ip);
 600         printk(KERN_INFO "%s: remote ethernet address %pM\n",
 601                          np->name, np->remote_mac);
 602 }
 603
 604 int netpoll_parse_options(struct netpoll *np, char *opt)
 605 {
 606         char *cur=opt, *delim;
 607
 608         if (*cur != '@') {
 609                 if ((delim = strchr(cur, '@')) == NULL)
 610                         goto parse_failed;
 611                 *delim = 0;
 612                 np->local_port = simple_strtol(cur, NULL, 10);
 613                 cur = delim;
 614         }
 615         cur++;
 616
 617         if (*cur != '/') {
 618                 if ((delim = strchr(cur, '/')) == NULL)
 619                         goto parse_failed;
 620                 *delim = 0;
 621                 np->local_ip = in_aton(cur);
 622                 cur = delim;
 623         }
 624         cur++;
 625
 626         if (*cur != ',') {
 627                 /* parse out dev name */
 628                 if ((delim = strchr(cur, ',')) == NULL)
 629                         goto parse_failed;
 630                 *delim = 0;
 631                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 632                 cur = delim;
 633         }
 634         cur++;
 635
 636         if (*cur != '@') {
 637                 /* dst port */
 638                 if ((delim = strchr(cur, '@')) == NULL)
 639                         goto parse_failed;
 640                 *delim = 0;
 641                 if (*cur == ' ' || *cur == '\t')
 642                         printk(KERN_INFO "%s: warning: whitespace"
 643                                         "is not allowed\n", np->name);
 644                 np->remote_port = simple_strtol(cur, NULL, 10);
 645                 cur = delim;
 646         }
 647         cur++;
 648
 649         /* dst ip */
 650         if ((delim = strchr(cur, '/')) == NULL)
 651                 goto parse_failed;
 652         *delim = 0;
 653         np->remote_ip = in_aton(cur);
 654         cur = delim + 1;
 655
 656         if (*cur != 0) {
 657                 /* MAC address */
 658                 if ((delim = strchr(cur, ':')) == NULL)
 659                         goto parse_failed;
 660                 *delim = 0;
 661                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 662                 cur = delim + 1;
 663                 if ((delim = strchr(cur, ':')) == NULL)
 664                         goto parse_failed;
 665                 *delim = 0;
 666                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 667                 cur = delim + 1;
 668                 if ((delim = strchr(cur, ':')) == NULL)
 669                         goto parse_failed;
 670                 *delim = 0;
 671                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 672                 cur = delim + 1;
 673                 if ((delim = strchr(cur, ':')) == NULL)
 674                         goto parse_failed;
 675                 *delim = 0;
 676                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 677                 cur = delim + 1;
 678                 if ((delim = strchr(cur, ':')) == NULL)
 679                         goto parse_failed;
 680                 *delim = 0;
 681                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 682                 cur = delim + 1;
 683                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 684         }
 685
 686         netpoll_print_options(np);
 687
 688         return 0;
 689
 690  parse_failed:
 691         printk(KERN_INFO "%s: couldn't parse config at '%s'!\n",
 692                np->name, cur);
 693         return -1;
 694 }
 695
 696 int netpoll_setup(struct netpoll *np)
 697 {
 698         struct net_device *ndev = NULL;
 699         struct in_device *in_dev;
 700         struct netpoll_info *npinfo;
 701         struct netpoll *npe, *tmp;
 702         unsigned long flags;
 703         int err;
 704
 705         if (np->dev_name)
 706                 ndev = dev_get_by_name(&init_net, np->dev_name);
 707         if (!ndev) {
 708                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 709                        np->name, np->dev_name);
 710                 return -ENODEV;
 711         }
 712
 713         np->dev = ndev;
 714         if (!ndev->npinfo) {
 715                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 716                 if (!npinfo) {
 717                         err = -ENOMEM;
 718                         goto put;
 719                 }
 720
 721                 npinfo->rx_flags = 0;
 722                 INIT_LIST_HEAD(&npinfo->rx_np);
 723
 724                 spin_lock_init(&npinfo->rx_lock);
 725                 skb_queue_head_init(&npinfo->arp_tx);
 726                 skb_queue_head_init(&npinfo->txq);
 727                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 728
 729                 atomic_set(&npinfo->refcnt, 1);
 730         } else {
 731                 npinfo = ndev->npinfo;
 732                 atomic_inc(&npinfo->refcnt);
 733         }
 734
 735         npinfo->netpoll = np;
 736
 737         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 738             !ndev->netdev_ops->ndo_poll_controller) {
 739                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 740                        np->name, np->dev_name);
 741                 err = -ENOTSUPP;
 742                 goto release;
 743         }
 744
 745         if (!netif_running(ndev)) {
 746                 unsigned long atmost, atleast;
 747
 748                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 749                        np->name, np->dev_name);
 750
 751                 rtnl_lock();
 752                 err = dev_open(ndev);
 753                 rtnl_unlock();
 754
 755                 if (err) {
 756                         printk(KERN_ERR "%s: failed to open %s\n",
 757                                np->name, ndev->name);
 758                         goto release;
 759                 }
 760
 761                 atleast = jiffies + HZ/10;
 762                 atmost = jiffies + carrier_timeout * HZ;
 763                 while (!netif_carrier_ok(ndev)) {
 764                         if (time_after(jiffies, atmost)) {
 765                                 printk(KERN_NOTICE
 766                                        "%s: timeout waiting for carrier\n",
 767                                        np->name);
 768                                 break;
 769                         }
 770                         msleep(1);
 771                 }
 772
 773                 /* If carrier appears to come up instantly, we don't
 774                  * trust it and pause so that we don't pump all our
 775                  * queued console messages into the bitbucket.
 776                  */
 777
 778                 if (time_before(jiffies, atleast)) {
 779                         printk(KERN_NOTICE "%s: carrier detect appears"
 780                                " untrustworthy, waiting 4 seconds\n",
 781                                np->name);
 782                         msleep(4000);
 783                 }
 784         }
 785
 786         if (!np->local_ip) {
 787                 rcu_read_lock();
 788                 in_dev = __in_dev_get_rcu(ndev);
 789
 790                 if (!in_dev || !in_dev->ifa_list) {
 791                         rcu_read_unlock();
 792                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 793                                np->name, np->dev_name);
 794                         err = -EDESTADDRREQ;
 795                         goto release;
 796                 }
 797
 798                 np->local_ip = in_dev->ifa_list->ifa_local;
 799                 rcu_read_unlock();
 800                 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
 801         }
 802
 803         if (np->rx_hook) {
 804                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 805                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 806                 list_add_tail(&np->rx, &npinfo->rx_np);
 807                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 808         }
 809
 810         /* fill up the skb queue */
 811         refill_skbs();
 812
 813         /* last thing to do is link it to the net device structure */
 814         rcu_assign_pointer(ndev->npinfo, npinfo);
 815
 816         return 0;
 817
 818  release:
 819         if (!ndev->npinfo) {
 820                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 821                 list_for_each_entry_safe(npe, tmp, &npinfo->rx_np, rx) {
 822                         npe->dev = NULL;
 823                 }
 824                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 825
 826                 kfree(npinfo);
 827         }
 828 put:
 829         dev_put(ndev);
 830         return err;
 831 }
 832
 833 static int __init netpoll_init(void)
 834 {
 835         skb_queue_head_init(&skb_pool);
 836         return 0;
 837 }
 838 core_initcall(netpoll_init);
 839
 840 void netpoll_cleanup(struct netpoll *np)
 841 {
 842         struct netpoll_info *npinfo;
 843         unsigned long flags;
 844
 845         if (np->dev) {
 846                 npinfo = np->dev->npinfo;
 847                 if (npinfo) {
 848                         if (!list_empty(&npinfo->rx_np)) {
 849                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 850                                 list_del(&np->rx);
 851                                 if (list_empty(&npinfo->rx_np))
 852                                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 853                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 854                         }
 855
 856                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 857                                 const struct net_device_ops *ops;
 858
 859                                 ops = np->dev->netdev_ops;
 860                                 if (ops->ndo_netpoll_cleanup)
 861                                         ops->ndo_netpoll_cleanup(np->dev);
 862
 863                                 rcu_assign_pointer(np->dev->npinfo, NULL);
 864
 865                                 /* avoid racing with NAPI reading npinfo */
 866                                 synchronize_rcu_bh();
 867
 868                                 skb_queue_purge(&npinfo->arp_tx);
 869                                 skb_queue_purge(&npinfo->txq);
 870                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 871
 872                                 /* clean after last, unfinished work */
 873                                 __skb_queue_purge(&npinfo->txq);
 874                                 kfree(npinfo);
 875                         }
 876                 }
 877
 878                 dev_put(np->dev);
 879         }
 880
 881         np->dev = NULL;
 882 }
 883
 884 int netpoll_trap(void)
 885 {
 886         return atomic_read(&trapped);
 887 }
 888
 889 void netpoll_set_trap(int trap)
 890 {
 891         if (trap)
 892                 atomic_inc(&trapped);
 893         else
 894                 atomic_dec(&trapped);
 895 }
 896
 897 EXPORT_SYMBOL(netpoll_send_skb);
 898 EXPORT_SYMBOL(netpoll_set_trap);
 899 EXPORT_SYMBOL(netpoll_trap);
 900 EXPORT_SYMBOL(netpoll_print_options);
 901 EXPORT_SYMBOL(netpoll_parse_options);
 902 EXPORT_SYMBOL(netpoll_setup);
 903 EXPORT_SYMBOL(netpoll_cleanup);
 904 EXPORT_SYMBOL(netpoll_send_udp);
 905 EXPORT_SYMBOL(netpoll_poll_dev);
 906 EXPORT_SYMBOL(netpoll_poll);