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 37static struct sk_buff_head skb_pool; 38 39static 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 49static void zap_completion_queue(void); 50static void arp_reply(struct sk_buff *skb); 51 52static 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 83static __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 */ 118static 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 137static 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 152void 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 167static 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 183static 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 209static 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(); 216repeat: 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 235static 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 /* try until next clock tick */ 254 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL; 255 tries > 0; --tries) { 256 if (netif_tx_trylock(dev)) { 257 if (!netif_queue_stopped(dev)) 258 status = dev->hard_start_xmit(skb, dev); 259 netif_tx_unlock(dev); 260 261 if (status == NETDEV_TX_OK) 262 break; 263 264 } 265 266 /* tickle device maybe there is some cleanup */ 267 netpoll_poll(np); 268 269 udelay(USEC_PER_POLL); 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 280void 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 341static 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 437int __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 511out: 512 if (atomic_read(&trapped)) { 513 kfree_skb(skb); 514 return 1; 515 } 516 517 return 0; 518} 519 520int 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 627int 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 762static int __init netpoll_init(void) 763{ 764 skb_queue_head_init(&skb_pool); 765 return 0; 766} 767core_initcall(netpoll_init); 768 769void 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); 789 790 /* clean after last, unfinished work */ 791 if (!skb_queue_empty(&npinfo->txq)) { 792 struct sk_buff *skb; 793 skb = __skb_dequeue(&npinfo->txq); 794 kfree_skb(skb); 795 } 796 kfree(npinfo); 797 } 798 } 799 800 dev_put(np->dev); 801 } 802 803 np->dev = NULL; 804} 805 806int netpoll_trap(void) 807{ 808 return atomic_read(&trapped); 809} 810 811void netpoll_set_trap(int trap) 812{ 813 if (trap) 814 atomic_inc(&trapped); 815 else 816 atomic_dec(&trapped); 817} 818 819EXPORT_SYMBOL(netpoll_set_trap); 820EXPORT_SYMBOL(netpoll_trap); 821EXPORT_SYMBOL(netpoll_parse_options); 822EXPORT_SYMBOL(netpoll_setup); 823EXPORT_SYMBOL(netpoll_cleanup); 824EXPORT_SYMBOL(netpoll_send_udp); 825EXPORT_SYMBOL(netpoll_poll); 826