linux/net/core/netpoll.c
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   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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14#include <linux/moduleparam.h>
  15#include <linux/netdevice.h>
  16#include <linux/etherdevice.h>
  17#include <linux/string.h>
  18#include <linux/if_arp.h>
  19#include <linux/inetdevice.h>
  20#include <linux/inet.h>
  21#include <linux/interrupt.h>
  22#include <linux/netpoll.h>
  23#include <linux/sched.h>
  24#include <linux/delay.h>
  25#include <linux/rcupdate.h>
  26#include <linux/workqueue.h>
  27#include <linux/slab.h>
  28#include <linux/export.h>
  29#include <linux/if_vlan.h>
  30#include <net/tcp.h>
  31#include <net/udp.h>
  32#include <asm/unaligned.h>
  33#include <trace/events/napi.h>
  34
  35/*
  36 * We maintain a small pool of fully-sized skbs, to make sure the
  37 * message gets out even in extreme OOM situations.
  38 */
  39
  40#define MAX_UDP_CHUNK 1460
  41#define MAX_SKBS 32
  42
  43static struct sk_buff_head skb_pool;
  44
  45static atomic_t trapped;
  46
  47#define USEC_PER_POLL   50
  48#define NETPOLL_RX_ENABLED  1
  49#define NETPOLL_RX_DROP     2
  50
  51#define MAX_SKB_SIZE                                                    \
  52        (sizeof(struct ethhdr) +                                        \
  53         sizeof(struct iphdr) +                                         \
  54         sizeof(struct udphdr) +                                        \
  55         MAX_UDP_CHUNK)
  56
  57static void zap_completion_queue(void);
  58static void netpoll_arp_reply(struct sk_buff *skb, struct netpoll_info *npinfo);
  59
  60static unsigned int carrier_timeout = 4;
  61module_param(carrier_timeout, uint, 0644);
  62
  63#define np_info(np, fmt, ...)                           \
  64        pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  65#define np_err(np, fmt, ...)                            \
  66        pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  67#define np_notice(np, fmt, ...)                         \
  68        pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  69
  70static void queue_process(struct work_struct *work)
  71{
  72        struct netpoll_info *npinfo =
  73                container_of(work, struct netpoll_info, tx_work.work);
  74        struct sk_buff *skb;
  75        unsigned long flags;
  76
  77        while ((skb = skb_dequeue(&npinfo->txq))) {
  78                struct net_device *dev = skb->dev;
  79                const struct net_device_ops *ops = dev->netdev_ops;
  80                struct netdev_queue *txq;
  81
  82                if (!netif_device_present(dev) || !netif_running(dev)) {
  83                        __kfree_skb(skb);
  84                        continue;
  85                }
  86
  87                txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  88
  89                local_irq_save(flags);
  90                __netif_tx_lock(txq, smp_processor_id());
  91                if (netif_xmit_frozen_or_stopped(txq) ||
  92                    ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  93                        skb_queue_head(&npinfo->txq, skb);
  94                        __netif_tx_unlock(txq);
  95                        local_irq_restore(flags);
  96
  97                        schedule_delayed_work(&npinfo->tx_work, HZ/10);
  98                        return;
  99                }
 100                __netif_tx_unlock(txq);
 101                local_irq_restore(flags);
 102        }
 103}
 104
 105static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 106                            unsigned short ulen, __be32 saddr, __be32 daddr)
 107{
 108        __wsum psum;
 109
 110        if (uh->check == 0 || skb_csum_unnecessary(skb))
 111                return 0;
 112
 113        psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 114
 115        if (skb->ip_summed == CHECKSUM_COMPLETE &&
 116            !csum_fold(csum_add(psum, skb->csum)))
 117                return 0;
 118
 119        skb->csum = psum;
 120
 121        return __skb_checksum_complete(skb);
 122}
 123
 124/*
 125 * Check whether delayed processing was scheduled for our NIC. If so,
 126 * we attempt to grab the poll lock and use ->poll() to pump the card.
 127 * If this fails, either we've recursed in ->poll() or it's already
 128 * running on another CPU.
 129 *
 130 * Note: we don't mask interrupts with this lock because we're using
 131 * trylock here and interrupts are already disabled in the softirq
 132 * case. Further, we test the poll_owner to avoid recursion on UP
 133 * systems where the lock doesn't exist.
 134 *
 135 * In cases where there is bi-directional communications, reading only
 136 * one message at a time can lead to packets being dropped by the
 137 * network adapter, forcing superfluous retries and possibly timeouts.
 138 * Thus, we set our budget to greater than 1.
 139 */
 140static int poll_one_napi(struct netpoll_info *npinfo,
 141                         struct napi_struct *napi, int budget)
 142{
 143        int work;
 144
 145        /* net_rx_action's ->poll() invocations and our's are
 146         * synchronized by this test which is only made while
 147         * holding the napi->poll_lock.
 148         */
 149        if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 150                return budget;
 151
 152        npinfo->rx_flags |= NETPOLL_RX_DROP;
 153        atomic_inc(&trapped);
 154        set_bit(NAPI_STATE_NPSVC, &napi->state);
 155
 156        work = napi->poll(napi, budget);
 157        trace_napi_poll(napi);
 158
 159        clear_bit(NAPI_STATE_NPSVC, &napi->state);
 160        atomic_dec(&trapped);
 161        npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 162
 163        return budget - work;
 164}
 165
 166static void poll_napi(struct net_device *dev)
 167{
 168        struct napi_struct *napi;
 169        int budget = 16;
 170
 171        list_for_each_entry(napi, &dev->napi_list, dev_list) {
 172                if (napi->poll_owner != smp_processor_id() &&
 173                    spin_trylock(&napi->poll_lock)) {
 174                        budget = poll_one_napi(rcu_dereference_bh(dev->npinfo),
 175                                               napi, budget);
 176                        spin_unlock(&napi->poll_lock);
 177
 178                        if (!budget)
 179                                break;
 180                }
 181        }
 182}
 183
 184static void service_arp_queue(struct netpoll_info *npi)
 185{
 186        if (npi) {
 187                struct sk_buff *skb;
 188
 189                while ((skb = skb_dequeue(&npi->arp_tx)))
 190                        netpoll_arp_reply(skb, npi);
 191        }
 192}
 193
 194static void netpoll_poll_dev(struct net_device *dev)
 195{
 196        const struct net_device_ops *ops;
 197        struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 198
 199        if (!dev || !netif_running(dev))
 200                return;
 201
 202        ops = dev->netdev_ops;
 203        if (!ops->ndo_poll_controller)
 204                return;
 205
 206        /* Process pending work on NIC */
 207        ops->ndo_poll_controller(dev);
 208
 209        poll_napi(dev);
 210
 211        if (dev->flags & IFF_SLAVE) {
 212                if (ni) {
 213                        struct net_device *bond_dev = dev->master;
 214                        struct sk_buff *skb;
 215                        struct netpoll_info *bond_ni = rcu_dereference_bh(bond_dev->npinfo);
 216                        while ((skb = skb_dequeue(&ni->arp_tx))) {
 217                                skb->dev = bond_dev;
 218                                skb_queue_tail(&bond_ni->arp_tx, skb);
 219                        }
 220                }
 221        }
 222
 223        service_arp_queue(ni);
 224
 225        zap_completion_queue();
 226}
 227
 228static void refill_skbs(void)
 229{
 230        struct sk_buff *skb;
 231        unsigned long flags;
 232
 233        spin_lock_irqsave(&skb_pool.lock, flags);
 234        while (skb_pool.qlen < MAX_SKBS) {
 235                skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 236                if (!skb)
 237                        break;
 238
 239                __skb_queue_tail(&skb_pool, skb);
 240        }
 241        spin_unlock_irqrestore(&skb_pool.lock, flags);
 242}
 243
 244static void zap_completion_queue(void)
 245{
 246        unsigned long flags;
 247        struct softnet_data *sd = &get_cpu_var(softnet_data);
 248
 249        if (sd->completion_queue) {
 250                struct sk_buff *clist;
 251
 252                local_irq_save(flags);
 253                clist = sd->completion_queue;
 254                sd->completion_queue = NULL;
 255                local_irq_restore(flags);
 256
 257                while (clist != NULL) {
 258                        struct sk_buff *skb = clist;
 259                        clist = clist->next;
 260                        if (skb->destructor) {
 261                                atomic_inc(&skb->users);
 262                                dev_kfree_skb_any(skb); /* put this one back */
 263                        } else {
 264                                __kfree_skb(skb);
 265                        }
 266                }
 267        }
 268
 269        put_cpu_var(softnet_data);
 270}
 271
 272static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 273{
 274        int count = 0;
 275        struct sk_buff *skb;
 276
 277        zap_completion_queue();
 278        refill_skbs();
 279repeat:
 280
 281        skb = alloc_skb(len, GFP_ATOMIC);
 282        if (!skb)
 283                skb = skb_dequeue(&skb_pool);
 284
 285        if (!skb) {
 286                if (++count < 10) {
 287                        netpoll_poll_dev(np->dev);
 288                        goto repeat;
 289                }
 290                return NULL;
 291        }
 292
 293        atomic_set(&skb->users, 1);
 294        skb_reserve(skb, reserve);
 295        return skb;
 296}
 297
 298static int netpoll_owner_active(struct net_device *dev)
 299{
 300        struct napi_struct *napi;
 301
 302        list_for_each_entry(napi, &dev->napi_list, dev_list) {
 303                if (napi->poll_owner == smp_processor_id())
 304                        return 1;
 305        }
 306        return 0;
 307}
 308
 309/* call with IRQ disabled */
 310void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 311                             struct net_device *dev)
 312{
 313        int status = NETDEV_TX_BUSY;
 314        unsigned long tries;
 315        const struct net_device_ops *ops = dev->netdev_ops;
 316        /* It is up to the caller to keep npinfo alive. */
 317        struct netpoll_info *npinfo;
 318
 319        WARN_ON_ONCE(!irqs_disabled());
 320
 321        npinfo = rcu_dereference_bh(np->dev->npinfo);
 322        if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 323                __kfree_skb(skb);
 324                return;
 325        }
 326
 327        /* don't get messages out of order, and no recursion */
 328        if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 329                struct netdev_queue *txq;
 330
 331                txq = netdev_pick_tx(dev, skb);
 332
 333                /* try until next clock tick */
 334                for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 335                     tries > 0; --tries) {
 336                        if (__netif_tx_trylock(txq)) {
 337                                if (!netif_xmit_stopped(txq)) {
 338                                        if (vlan_tx_tag_present(skb) &&
 339                                            !(netif_skb_features(skb) & NETIF_F_HW_VLAN_TX)) {
 340                                                skb = __vlan_put_tag(skb, vlan_tx_tag_get(skb));
 341                                                if (unlikely(!skb))
 342                                                        break;
 343                                                skb->vlan_tci = 0;
 344                                        }
 345
 346                                        status = ops->ndo_start_xmit(skb, dev);
 347                                        if (status == NETDEV_TX_OK)
 348                                                txq_trans_update(txq);
 349                                }
 350                                __netif_tx_unlock(txq);
 351
 352                                if (status == NETDEV_TX_OK)
 353                                        break;
 354
 355                        }
 356
 357                        /* tickle device maybe there is some cleanup */
 358                        netpoll_poll_dev(np->dev);
 359
 360                        udelay(USEC_PER_POLL);
 361                }
 362
 363                WARN_ONCE(!irqs_disabled(),
 364                        "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 365                        dev->name, ops->ndo_start_xmit);
 366
 367        }
 368
 369        if (status != NETDEV_TX_OK) {
 370                skb_queue_tail(&npinfo->txq, skb);
 371                schedule_delayed_work(&npinfo->tx_work,0);
 372        }
 373}
 374EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 375
 376void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 377{
 378        int total_len, ip_len, udp_len;
 379        struct sk_buff *skb;
 380        struct udphdr *udph;
 381        struct iphdr *iph;
 382        struct ethhdr *eth;
 383        static atomic_t ip_ident;
 384
 385        udp_len = len + sizeof(*udph);
 386        ip_len = udp_len + sizeof(*iph);
 387        total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 388
 389        skb = find_skb(np, total_len + np->dev->needed_tailroom,
 390                       total_len - len);
 391        if (!skb)
 392                return;
 393
 394        skb_copy_to_linear_data(skb, msg, len);
 395        skb_put(skb, len);
 396
 397        skb_push(skb, sizeof(*udph));
 398        skb_reset_transport_header(skb);
 399        udph = udp_hdr(skb);
 400        udph->source = htons(np->local_port);
 401        udph->dest = htons(np->remote_port);
 402        udph->len = htons(udp_len);
 403        udph->check = 0;
 404        udph->check = csum_tcpudp_magic(np->local_ip,
 405                                        np->remote_ip,
 406                                        udp_len, IPPROTO_UDP,
 407                                        csum_partial(udph, udp_len, 0));
 408        if (udph->check == 0)
 409                udph->check = CSUM_MANGLED_0;
 410
 411        skb_push(skb, sizeof(*iph));
 412        skb_reset_network_header(skb);
 413        iph = ip_hdr(skb);
 414
 415        /* iph->version = 4; iph->ihl = 5; */
 416        put_unaligned(0x45, (unsigned char *)iph);
 417        iph->tos      = 0;
 418        put_unaligned(htons(ip_len), &(iph->tot_len));
 419        iph->id       = htons(atomic_inc_return(&ip_ident));
 420        iph->frag_off = 0;
 421        iph->ttl      = 64;
 422        iph->protocol = IPPROTO_UDP;
 423        iph->check    = 0;
 424        put_unaligned(np->local_ip, &(iph->saddr));
 425        put_unaligned(np->remote_ip, &(iph->daddr));
 426        iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 427
 428        eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 429        skb_reset_mac_header(skb);
 430        skb->protocol = eth->h_proto = htons(ETH_P_IP);
 431        memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 432        memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 433
 434        skb->dev = np->dev;
 435
 436        netpoll_send_skb(np, skb);
 437}
 438EXPORT_SYMBOL(netpoll_send_udp);
 439
 440static void netpoll_arp_reply(struct sk_buff *skb, struct netpoll_info *npinfo)
 441{
 442        struct arphdr *arp;
 443        unsigned char *arp_ptr;
 444        int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 445        __be32 sip, tip;
 446        unsigned char *sha;
 447        struct sk_buff *send_skb;
 448        struct netpoll *np, *tmp;
 449        unsigned long flags;
 450        int hlen, tlen;
 451        int hits = 0;
 452
 453        if (list_empty(&npinfo->rx_np))
 454                return;
 455
 456        /* Before checking the packet, we do some early
 457           inspection whether this is interesting at all */
 458        spin_lock_irqsave(&npinfo->rx_lock, flags);
 459        list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 460                if (np->dev == skb->dev)
 461                        hits++;
 462        }
 463        spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 464
 465        /* No netpoll struct is using this dev */
 466        if (!hits)
 467                return;
 468
 469        /* No arp on this interface */
 470        if (skb->dev->flags & IFF_NOARP)
 471                return;
 472
 473        if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 474                return;
 475
 476        skb_reset_network_header(skb);
 477        skb_reset_transport_header(skb);
 478        arp = arp_hdr(skb);
 479
 480        if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 481             arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 482            arp->ar_pro != htons(ETH_P_IP) ||
 483            arp->ar_op != htons(ARPOP_REQUEST))
 484                return;
 485
 486        arp_ptr = (unsigned char *)(arp+1);
 487        /* save the location of the src hw addr */
 488        sha = arp_ptr;
 489        arp_ptr += skb->dev->addr_len;
 490        memcpy(&sip, arp_ptr, 4);
 491        arp_ptr += 4;
 492        /* If we actually cared about dst hw addr,
 493           it would get copied here */
 494        arp_ptr += skb->dev->addr_len;
 495        memcpy(&tip, arp_ptr, 4);
 496
 497        /* Should we ignore arp? */
 498        if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 499                return;
 500
 501        size = arp_hdr_len(skb->dev);
 502
 503        spin_lock_irqsave(&npinfo->rx_lock, flags);
 504        list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 505                if (tip != np->local_ip)
 506                        continue;
 507
 508                hlen = LL_RESERVED_SPACE(np->dev);
 509                tlen = np->dev->needed_tailroom;
 510                send_skb = find_skb(np, size + hlen + tlen, hlen);
 511                if (!send_skb)
 512                        continue;
 513
 514                skb_reset_network_header(send_skb);
 515                arp = (struct arphdr *) skb_put(send_skb, size);
 516                send_skb->dev = skb->dev;
 517                send_skb->protocol = htons(ETH_P_ARP);
 518
 519                /* Fill the device header for the ARP frame */
 520                if (dev_hard_header(send_skb, skb->dev, ptype,
 521                                    sha, np->dev->dev_addr,
 522                                    send_skb->len) < 0) {
 523                        kfree_skb(send_skb);
 524                        continue;
 525                }
 526
 527                /*
 528                 * Fill out the arp protocol part.
 529                 *
 530                 * we only support ethernet device type,
 531                 * which (according to RFC 1390) should
 532                 * always equal 1 (Ethernet).
 533                 */
 534
 535                arp->ar_hrd = htons(np->dev->type);
 536                arp->ar_pro = htons(ETH_P_IP);
 537                arp->ar_hln = np->dev->addr_len;
 538                arp->ar_pln = 4;
 539                arp->ar_op = htons(type);
 540
 541                arp_ptr = (unsigned char *)(arp + 1);
 542                memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 543                arp_ptr += np->dev->addr_len;
 544                memcpy(arp_ptr, &tip, 4);
 545                arp_ptr += 4;
 546                memcpy(arp_ptr, sha, np->dev->addr_len);
 547                arp_ptr += np->dev->addr_len;
 548                memcpy(arp_ptr, &sip, 4);
 549
 550                netpoll_send_skb(np, send_skb);
 551
 552                /* If there are several rx_hooks for the same address,
 553                   we're fine by sending a single reply */
 554                break;
 555        }
 556        spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 557}
 558
 559int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo)
 560{
 561        int proto, len, ulen;
 562        int hits = 0;
 563        const struct iphdr *iph;
 564        struct udphdr *uh;
 565        struct netpoll *np, *tmp;
 566
 567        if (list_empty(&npinfo->rx_np))
 568                goto out;
 569
 570        if (skb->dev->type != ARPHRD_ETHER)
 571                goto out;
 572
 573        /* check if netpoll clients need ARP */
 574        if (skb->protocol == htons(ETH_P_ARP) &&
 575            atomic_read(&trapped)) {
 576                skb_queue_tail(&npinfo->arp_tx, skb);
 577                return 1;
 578        }
 579
 580        if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
 581                skb = vlan_untag(skb);
 582                if (unlikely(!skb))
 583                        goto out;
 584        }
 585
 586        proto = ntohs(eth_hdr(skb)->h_proto);
 587        if (proto != ETH_P_IP)
 588                goto out;
 589        if (skb->pkt_type == PACKET_OTHERHOST)
 590                goto out;
 591        if (skb_shared(skb))
 592                goto out;
 593
 594        if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 595                goto out;
 596        iph = (struct iphdr *)skb->data;
 597        if (iph->ihl < 5 || iph->version != 4)
 598                goto out;
 599        if (!pskb_may_pull(skb, iph->ihl*4))
 600                goto out;
 601        iph = (struct iphdr *)skb->data;
 602        if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 603                goto out;
 604
 605        len = ntohs(iph->tot_len);
 606        if (skb->len < len || len < iph->ihl*4)
 607                goto out;
 608
 609        /*
 610         * Our transport medium may have padded the buffer out.
 611         * Now We trim to the true length of the frame.
 612         */
 613        if (pskb_trim_rcsum(skb, len))
 614                goto out;
 615
 616        iph = (struct iphdr *)skb->data;
 617        if (iph->protocol != IPPROTO_UDP)
 618                goto out;
 619
 620        len -= iph->ihl*4;
 621        uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 622        ulen = ntohs(uh->len);
 623
 624        if (ulen != len)
 625                goto out;
 626        if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 627                goto out;
 628
 629        list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 630                if (np->local_ip && np->local_ip != iph->daddr)
 631                        continue;
 632                if (np->remote_ip && np->remote_ip != iph->saddr)
 633                        continue;
 634                if (np->local_port && np->local_port != ntohs(uh->dest))
 635                        continue;
 636
 637                np->rx_hook(np, ntohs(uh->source),
 638                               (char *)(uh+1),
 639                               ulen - sizeof(struct udphdr));
 640                hits++;
 641        }
 642
 643        if (!hits)
 644                goto out;
 645
 646        kfree_skb(skb);
 647        return 1;
 648
 649out:
 650        if (atomic_read(&trapped)) {
 651                kfree_skb(skb);
 652                return 1;
 653        }
 654
 655        return 0;
 656}
 657
 658void netpoll_print_options(struct netpoll *np)
 659{
 660        np_info(np, "local port %d\n", np->local_port);
 661        np_info(np, "local IP %pI4\n", &np->local_ip);
 662        np_info(np, "interface '%s'\n", np->dev_name);
 663        np_info(np, "remote port %d\n", np->remote_port);
 664        np_info(np, "remote IP %pI4\n", &np->remote_ip);
 665        np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 666}
 667EXPORT_SYMBOL(netpoll_print_options);
 668
 669int netpoll_parse_options(struct netpoll *np, char *opt)
 670{
 671        char *cur=opt, *delim;
 672
 673        if (*cur != '@') {
 674                if ((delim = strchr(cur, '@')) == NULL)
 675                        goto parse_failed;
 676                *delim = 0;
 677                np->local_port = simple_strtol(cur, NULL, 10);
 678                cur = delim;
 679        }
 680        cur++;
 681
 682        if (*cur != '/') {
 683                if ((delim = strchr(cur, '/')) == NULL)
 684                        goto parse_failed;
 685                *delim = 0;
 686                np->local_ip = in_aton(cur);
 687                cur = delim;
 688        }
 689        cur++;
 690
 691        if (*cur != ',') {
 692                /* parse out dev name */
 693                if ((delim = strchr(cur, ',')) == NULL)
 694                        goto parse_failed;
 695                *delim = 0;
 696                strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 697                cur = delim;
 698        }
 699        cur++;
 700
 701        if (*cur != '@') {
 702                /* dst port */
 703                if ((delim = strchr(cur, '@')) == NULL)
 704                        goto parse_failed;
 705                *delim = 0;
 706                if (*cur == ' ' || *cur == '\t')
 707                        np_info(np, "warning: whitespace is not allowed\n");
 708                np->remote_port = simple_strtol(cur, NULL, 10);
 709                cur = delim;
 710        }
 711        cur++;
 712
 713        /* dst ip */
 714        if ((delim = strchr(cur, '/')) == NULL)
 715                goto parse_failed;
 716        *delim = 0;
 717        np->remote_ip = in_aton(cur);
 718        cur = delim + 1;
 719
 720        if (*cur != 0) {
 721                /* MAC address */
 722                if (!mac_pton(cur, np->remote_mac))
 723                        goto parse_failed;
 724        }
 725
 726        netpoll_print_options(np);
 727
 728        return 0;
 729
 730 parse_failed:
 731        np_info(np, "couldn't parse config at '%s'!\n", cur);
 732        return -1;
 733}
 734EXPORT_SYMBOL(netpoll_parse_options);
 735
 736int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
 737{
 738        struct netpoll_info *npinfo;
 739        const struct net_device_ops *ops;
 740        unsigned long flags;
 741        int err;
 742
 743        np->dev = ndev;
 744        strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 745
 746        if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 747            !ndev->netdev_ops->ndo_poll_controller) {
 748                np_err(np, "%s doesn't support polling, aborting\n",
 749                       np->dev_name);
 750                err = -ENOTSUPP;
 751                goto out;
 752        }
 753
 754        if (!ndev->npinfo) {
 755                npinfo = kmalloc(sizeof(*npinfo), gfp);
 756                if (!npinfo) {
 757                        err = -ENOMEM;
 758                        goto out;
 759                }
 760
 761                npinfo->rx_flags = 0;
 762                INIT_LIST_HEAD(&npinfo->rx_np);
 763
 764                spin_lock_init(&npinfo->rx_lock);
 765                skb_queue_head_init(&npinfo->arp_tx);
 766                skb_queue_head_init(&npinfo->txq);
 767                INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 768
 769                atomic_set(&npinfo->refcnt, 1);
 770
 771                ops = np->dev->netdev_ops;
 772                if (ops->ndo_netpoll_setup) {
 773                        err = ops->ndo_netpoll_setup(ndev, npinfo, gfp);
 774                        if (err)
 775                                goto free_npinfo;
 776                }
 777        } else {
 778                npinfo = ndev->npinfo;
 779                atomic_inc(&npinfo->refcnt);
 780        }
 781
 782        npinfo->netpoll = np;
 783
 784        if (np->rx_hook) {
 785                spin_lock_irqsave(&npinfo->rx_lock, flags);
 786                npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 787                list_add_tail(&np->rx, &npinfo->rx_np);
 788                spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 789        }
 790
 791        /* last thing to do is link it to the net device structure */
 792        rcu_assign_pointer(ndev->npinfo, npinfo);
 793
 794        return 0;
 795
 796free_npinfo:
 797        kfree(npinfo);
 798out:
 799        return err;
 800}
 801EXPORT_SYMBOL_GPL(__netpoll_setup);
 802
 803int netpoll_setup(struct netpoll *np)
 804{
 805        struct net_device *ndev = NULL;
 806        struct in_device *in_dev;
 807        int err;
 808
 809        if (np->dev_name)
 810                ndev = dev_get_by_name(&init_net, np->dev_name);
 811        if (!ndev) {
 812                np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 813                return -ENODEV;
 814        }
 815
 816        if (ndev->master) {
 817                np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 818                err = -EBUSY;
 819                goto put;
 820        }
 821
 822        if (!netif_running(ndev)) {
 823                unsigned long atmost, atleast;
 824
 825                np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 826
 827                rtnl_lock();
 828                err = dev_open(ndev);
 829                rtnl_unlock();
 830
 831                if (err) {
 832                        np_err(np, "failed to open %s\n", ndev->name);
 833                        goto put;
 834                }
 835
 836                atleast = jiffies + HZ/10;
 837                atmost = jiffies + carrier_timeout * HZ;
 838                while (!netif_carrier_ok(ndev)) {
 839                        if (time_after(jiffies, atmost)) {
 840                                np_notice(np, "timeout waiting for carrier\n");
 841                                break;
 842                        }
 843                        msleep(1);
 844                }
 845
 846                /* If carrier appears to come up instantly, we don't
 847                 * trust it and pause so that we don't pump all our
 848                 * queued console messages into the bitbucket.
 849                 */
 850
 851                if (time_before(jiffies, atleast)) {
 852                        np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 853                        msleep(4000);
 854                }
 855        }
 856
 857        if (!np->local_ip) {
 858                rcu_read_lock();
 859                in_dev = __in_dev_get_rcu(ndev);
 860
 861                if (!in_dev || !in_dev->ifa_list) {
 862                        rcu_read_unlock();
 863                        np_err(np, "no IP address for %s, aborting\n",
 864                               np->dev_name);
 865                        err = -EDESTADDRREQ;
 866                        goto put;
 867                }
 868
 869                np->local_ip = in_dev->ifa_list->ifa_local;
 870                rcu_read_unlock();
 871                np_info(np, "local IP %pI4\n", &np->local_ip);
 872        }
 873
 874        /* fill up the skb queue */
 875        refill_skbs();
 876
 877        rtnl_lock();
 878        err = __netpoll_setup(np, ndev, GFP_KERNEL);
 879        rtnl_unlock();
 880
 881        if (err)
 882                goto put;
 883
 884        return 0;
 885
 886put:
 887        dev_put(ndev);
 888        return err;
 889}
 890EXPORT_SYMBOL(netpoll_setup);
 891
 892static int __init netpoll_init(void)
 893{
 894        skb_queue_head_init(&skb_pool);
 895        return 0;
 896}
 897core_initcall(netpoll_init);
 898
 899static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 900{
 901        struct netpoll_info *npinfo =
 902                        container_of(rcu_head, struct netpoll_info, rcu);
 903
 904        skb_queue_purge(&npinfo->arp_tx);
 905        skb_queue_purge(&npinfo->txq);
 906
 907        /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 908        cancel_delayed_work(&npinfo->tx_work);
 909
 910        /* clean after last, unfinished work */
 911        __skb_queue_purge(&npinfo->txq);
 912        /* now cancel it again */
 913        cancel_delayed_work(&npinfo->tx_work);
 914        kfree(npinfo);
 915}
 916
 917void __netpoll_cleanup(struct netpoll *np)
 918{
 919        struct netpoll_info *npinfo;
 920        unsigned long flags;
 921
 922        npinfo = np->dev->npinfo;
 923        if (!npinfo)
 924                return;
 925
 926        if (!list_empty(&npinfo->rx_np)) {
 927                spin_lock_irqsave(&npinfo->rx_lock, flags);
 928                list_del(&np->rx);
 929                if (list_empty(&npinfo->rx_np))
 930                        npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 931                spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 932        }
 933
 934        if (atomic_dec_and_test(&npinfo->refcnt)) {
 935                const struct net_device_ops *ops;
 936
 937                ops = np->dev->netdev_ops;
 938                if (ops->ndo_netpoll_cleanup)
 939                        ops->ndo_netpoll_cleanup(np->dev);
 940
 941                RCU_INIT_POINTER(np->dev->npinfo, NULL);
 942                call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
 943        }
 944}
 945EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 946
 947static void rcu_cleanup_netpoll(struct rcu_head *rcu_head)
 948{
 949        struct netpoll *np = container_of(rcu_head, struct netpoll, rcu);
 950
 951        __netpoll_cleanup(np);
 952        kfree(np);
 953}
 954
 955void __netpoll_free_rcu(struct netpoll *np)
 956{
 957        call_rcu_bh(&np->rcu, rcu_cleanup_netpoll);
 958}
 959EXPORT_SYMBOL_GPL(__netpoll_free_rcu);
 960
 961void netpoll_cleanup(struct netpoll *np)
 962{
 963        if (!np->dev)
 964                return;
 965
 966        rtnl_lock();
 967        __netpoll_cleanup(np);
 968        rtnl_unlock();
 969
 970        dev_put(np->dev);
 971        np->dev = NULL;
 972}
 973EXPORT_SYMBOL(netpoll_cleanup);
 974
 975int netpoll_trap(void)
 976{
 977        return atomic_read(&trapped);
 978}
 979EXPORT_SYMBOL(netpoll_trap);
 980
 981void netpoll_set_trap(int trap)
 982{
 983        if (trap)
 984                atomic_inc(&trapped);
 985        else
 986                atomic_dec(&trapped);
 987}
 988EXPORT_SYMBOL(netpoll_set_trap);
 989
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