net/core/netpoll.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Common framework for low-level network console, dump, and debugger code
0004  *
0005  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
0006  *
0007  * based on the netconsole code from:
0008  *
0009  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
0010  * Copyright (C) 2002  Red Hat, Inc.
0011  */
0012
0013 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0014
0015 #include <linux/moduleparam.h>
0016 #include <linux/kernel.h>
0017 #include <linux/netdevice.h>
0018 #include <linux/etherdevice.h>
0019 #include <linux/string.h>
0020 #include <linux/if_arp.h>
0021 #include <linux/inetdevice.h>
0022 #include <linux/inet.h>
0023 #include <linux/interrupt.h>
0024 #include <linux/netpoll.h>
0025 #include <linux/sched.h>
0026 #include <linux/delay.h>
0027 #include <linux/rcupdate.h>
0028 #include <linux/workqueue.h>
0029 #include <linux/slab.h>
0030 #include <linux/export.h>
0031 #include <linux/if_vlan.h>
0032 #include <net/tcp.h>
0033 #include <net/udp.h>
0034 #include <net/addrconf.h>
0035 #include <net/ndisc.h>
0036 #include <net/ip6_checksum.h>
0037 #include <asm/unaligned.h>
0038 #include <trace/events/napi.h>
0039 #include <linux/kconfig.h>
0040
0041 /*
0042  * We maintain a small pool of fully-sized skbs, to make sure the
0043  * message gets out even in extreme OOM situations.
0044  */
0045
0046 #define MAX_UDP_CHUNK 1460
0047 #define MAX_SKBS 32
0048
0049 static struct sk_buff_head skb_pool;
0050
0051 DEFINE_STATIC_SRCU(netpoll_srcu);
0052
0053 #define USEC_PER_POLL   50
0054
0055 #define MAX_SKB_SIZE                            \
0056     (sizeof(struct ethhdr) +                    \
0057      sizeof(struct iphdr) +                     \
0058      sizeof(struct udphdr) +                    \
0059      MAX_UDP_CHUNK)
0060
0061 static void zap_completion_queue(void);
0062
0063 static unsigned int carrier_timeout = 4;
0064 module_param(carrier_timeout, uint, 0644);
0065
0066 #define np_info(np, fmt, ...)               \
0067     pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
0068 #define np_err(np, fmt, ...)                \
0069     pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
0070 #define np_notice(np, fmt, ...)             \
0071     pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
0072
0073 static netdev_tx_t netpoll_start_xmit(struct sk_buff *skb,
0074                       struct net_device *dev,
0075                       struct netdev_queue *txq)
0076 {
0077     netdev_tx_t status = NETDEV_TX_OK;
0078     netdev_features_t features;
0079
0080     features = netif_skb_features(skb);
0081
0082     if (skb_vlan_tag_present(skb) &&
0083         !vlan_hw_offload_capable(features, skb->vlan_proto)) {
0084         skb = __vlan_hwaccel_push_inside(skb);
0085         if (unlikely(!skb)) {
0086             /* This is actually a packet drop, but we
0087              * don't want the code that calls this
0088              * function to try and operate on a NULL skb.
0089              */
0090             goto out;
0091         }
0092     }
0093
0094     status = netdev_start_xmit(skb, dev, txq, false);
0095
0096 out:
0097     return status;
0098 }
0099
0100 static void queue_process(struct work_struct *work)
0101 {
0102     struct netpoll_info *npinfo =
0103         container_of(work, struct netpoll_info, tx_work.work);
0104     struct sk_buff *skb;
0105     unsigned long flags;
0106
0107     while ((skb = skb_dequeue(&npinfo->txq))) {
0108         struct net_device *dev = skb->dev;
0109         struct netdev_queue *txq;
0110         unsigned int q_index;
0111
0112         if (!netif_device_present(dev) || !netif_running(dev)) {
0113             kfree_skb(skb);
0114             continue;
0115         }
0116
0117         local_irq_save(flags);
0118         /* check if skb->queue_mapping is still valid */
0119         q_index = skb_get_queue_mapping(skb);
0120         if (unlikely(q_index >= dev->real_num_tx_queues)) {
0121             q_index = q_index % dev->real_num_tx_queues;
0122             skb_set_queue_mapping(skb, q_index);
0123         }
0124         txq = netdev_get_tx_queue(dev, q_index);
0125         HARD_TX_LOCK(dev, txq, smp_processor_id());
0126         if (netif_xmit_frozen_or_stopped(txq) ||
0127             !dev_xmit_complete(netpoll_start_xmit(skb, dev, txq))) {
0128             skb_queue_head(&npinfo->txq, skb);
0129             HARD_TX_UNLOCK(dev, txq);
0130             local_irq_restore(flags);
0131
0132             schedule_delayed_work(&npinfo->tx_work, HZ/10);
0133             return;
0134         }
0135         HARD_TX_UNLOCK(dev, txq);
0136         local_irq_restore(flags);
0137     }
0138 }
0139
0140 static void poll_one_napi(struct napi_struct *napi)
0141 {
0142     int work;
0143
0144     /* If we set this bit but see that it has already been set,
0145      * that indicates that napi has been disabled and we need
0146      * to abort this operation
0147      */
0148     if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
0149         return;
0150
0151     /* We explicilty pass the polling call a budget of 0 to
0152      * indicate that we are clearing the Tx path only.
0153      */
0154     work = napi->poll(napi, 0);
0155     WARN_ONCE(work, "%pS exceeded budget in poll\n", napi->poll);
0156     trace_napi_poll(napi, work, 0);
0157
0158     clear_bit(NAPI_STATE_NPSVC, &napi->state);
0159 }
0160
0161 static void poll_napi(struct net_device *dev)
0162 {
0163     struct napi_struct *napi;
0164     int cpu = smp_processor_id();
0165
0166     list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
0167         if (cmpxchg(&napi->poll_owner, -1, cpu) == -1) {
0168             poll_one_napi(napi);
0169             smp_store_release(&napi->poll_owner, -1);
0170         }
0171     }
0172 }
0173
0174 void netpoll_poll_dev(struct net_device *dev)
0175 {
0176     struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
0177     const struct net_device_ops *ops;
0178
0179     /* Don't do any rx activity if the dev_lock mutex is held
0180      * the dev_open/close paths use this to block netpoll activity
0181      * while changing device state
0182      */
0183     if (!ni || down_trylock(&ni->dev_lock))
0184         return;
0185
0186     if (!netif_running(dev)) {
0187         up(&ni->dev_lock);
0188         return;
0189     }
0190
0191     ops = dev->netdev_ops;
0192     if (ops->ndo_poll_controller)
0193         ops->ndo_poll_controller(dev);
0194
0195     poll_napi(dev);
0196
0197     up(&ni->dev_lock);
0198
0199     zap_completion_queue();
0200 }
0201 EXPORT_SYMBOL(netpoll_poll_dev);
0202
0203 void netpoll_poll_disable(struct net_device *dev)
0204 {
0205     struct netpoll_info *ni;
0206     int idx;
0207     might_sleep();
0208     idx = srcu_read_lock(&netpoll_srcu);
0209     ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
0210     if (ni)
0211         down(&ni->dev_lock);
0212     srcu_read_unlock(&netpoll_srcu, idx);
0213 }
0214 EXPORT_SYMBOL(netpoll_poll_disable);
0215
0216 void netpoll_poll_enable(struct net_device *dev)
0217 {
0218     struct netpoll_info *ni;
0219     rcu_read_lock();
0220     ni = rcu_dereference(dev->npinfo);
0221     if (ni)
0222         up(&ni->dev_lock);
0223     rcu_read_unlock();
0224 }
0225 EXPORT_SYMBOL(netpoll_poll_enable);
0226
0227 static void refill_skbs(void)
0228 {
0229     struct sk_buff *skb;
0230     unsigned long flags;
0231
0232     spin_lock_irqsave(&skb_pool.lock, flags);
0233     while (skb_pool.qlen < MAX_SKBS) {
0234         skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
0235         if (!skb)
0236             break;
0237
0238         __skb_queue_tail(&skb_pool, skb);
0239     }
0240     spin_unlock_irqrestore(&skb_pool.lock, flags);
0241 }
0242
0243 static void zap_completion_queue(void)
0244 {
0245     unsigned long flags;
0246     struct softnet_data *sd = &get_cpu_var(softnet_data);
0247
0248     if (sd->completion_queue) {
0249         struct sk_buff *clist;
0250
0251         local_irq_save(flags);
0252         clist = sd->completion_queue;
0253         sd->completion_queue = NULL;
0254         local_irq_restore(flags);
0255
0256         while (clist != NULL) {
0257             struct sk_buff *skb = clist;
0258             clist = clist->next;
0259             if (!skb_irq_freeable(skb)) {
0260                 refcount_set(&skb->users, 1);
0261                 dev_kfree_skb_any(skb); /* put this one back */
0262             } else {
0263                 __kfree_skb(skb);
0264             }
0265         }
0266     }
0267
0268     put_cpu_var(softnet_data);
0269 }
0270
0271 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
0272 {
0273     int count = 0;
0274     struct sk_buff *skb;
0275
0276     zap_completion_queue();
0277     refill_skbs();
0278 repeat:
0279
0280     skb = alloc_skb(len, GFP_ATOMIC);
0281     if (!skb)
0282         skb = skb_dequeue(&skb_pool);
0283
0284     if (!skb) {
0285         if (++count < 10) {
0286             netpoll_poll_dev(np->dev);
0287             goto repeat;
0288         }
0289         return NULL;
0290     }
0291
0292     refcount_set(&skb->users, 1);
0293     skb_reserve(skb, reserve);
0294     return skb;
0295 }
0296
0297 static int netpoll_owner_active(struct net_device *dev)
0298 {
0299     struct napi_struct *napi;
0300
0301     list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
0302         if (napi->poll_owner == smp_processor_id())
0303             return 1;
0304     }
0305     return 0;
0306 }
0307
0308 /* call with IRQ disabled */
0309 static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
0310 {
0311     netdev_tx_t status = NETDEV_TX_BUSY;
0312     struct net_device *dev;
0313     unsigned long tries;
0314     /* It is up to the caller to keep npinfo alive. */
0315     struct netpoll_info *npinfo;
0316
0317     lockdep_assert_irqs_disabled();
0318
0319     dev = np->dev;
0320     npinfo = rcu_dereference_bh(dev->npinfo);
0321
0322     if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
0323         dev_kfree_skb_irq(skb);
0324         return NET_XMIT_DROP;
0325     }
0326
0327     /* don't get messages out of order, and no recursion */
0328     if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
0329         struct netdev_queue *txq;
0330
0331         txq = netdev_core_pick_tx(dev, skb, NULL);
0332
0333         /* try until next clock tick */
0334         for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
0335              tries > 0; --tries) {
0336             if (HARD_TX_TRYLOCK(dev, txq)) {
0337                 if (!netif_xmit_stopped(txq))
0338                     status = netpoll_start_xmit(skb, dev, txq);
0339
0340                 HARD_TX_UNLOCK(dev, txq);
0341
0342                 if (dev_xmit_complete(status))
0343                     break;
0344
0345             }
0346
0347             /* tickle device maybe there is some cleanup */
0348             netpoll_poll_dev(np->dev);
0349
0350             udelay(USEC_PER_POLL);
0351         }
0352
0353         WARN_ONCE(!irqs_disabled(),
0354             "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pS)\n",
0355             dev->name, dev->netdev_ops->ndo_start_xmit);
0356
0357     }
0358
0359     if (!dev_xmit_complete(status)) {
0360         skb_queue_tail(&npinfo->txq, skb);
0361         schedule_delayed_work(&npinfo->tx_work,0);
0362     }
0363     return NETDEV_TX_OK;
0364 }
0365
0366 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
0367 {
0368     unsigned long flags;
0369     netdev_tx_t ret;
0370
0371     if (unlikely(!np)) {
0372         dev_kfree_skb_irq(skb);
0373         ret = NET_XMIT_DROP;
0374     } else {
0375         local_irq_save(flags);
0376         ret = __netpoll_send_skb(np, skb);
0377         local_irq_restore(flags);
0378     }
0379     return ret;
0380 }
0381 EXPORT_SYMBOL(netpoll_send_skb);
0382
0383 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
0384 {
0385     int total_len, ip_len, udp_len;
0386     struct sk_buff *skb;
0387     struct udphdr *udph;
0388     struct iphdr *iph;
0389     struct ethhdr *eth;
0390     static atomic_t ip_ident;
0391     struct ipv6hdr *ip6h;
0392
0393     if (!IS_ENABLED(CONFIG_PREEMPT_RT))
0394         WARN_ON_ONCE(!irqs_disabled());
0395
0396     udp_len = len + sizeof(*udph);
0397     if (np->ipv6)
0398         ip_len = udp_len + sizeof(*ip6h);
0399     else
0400         ip_len = udp_len + sizeof(*iph);
0401
0402     total_len = ip_len + LL_RESERVED_SPACE(np->dev);
0403
0404     skb = find_skb(np, total_len + np->dev->needed_tailroom,
0405                total_len - len);
0406     if (!skb)
0407         return;
0408
0409     skb_copy_to_linear_data(skb, msg, len);
0410     skb_put(skb, len);
0411
0412     skb_push(skb, sizeof(*udph));
0413     skb_reset_transport_header(skb);
0414     udph = udp_hdr(skb);
0415     udph->source = htons(np->local_port);
0416     udph->dest = htons(np->remote_port);
0417     udph->len = htons(udp_len);
0418
0419     if (np->ipv6) {
0420         udph->check = 0;
0421         udph->check = csum_ipv6_magic(&np->local_ip.in6,
0422                           &np->remote_ip.in6,
0423                           udp_len, IPPROTO_UDP,
0424                           csum_partial(udph, udp_len, 0));
0425         if (udph->check == 0)
0426             udph->check = CSUM_MANGLED_0;
0427
0428         skb_push(skb, sizeof(*ip6h));
0429         skb_reset_network_header(skb);
0430         ip6h = ipv6_hdr(skb);
0431
0432         /* ip6h->version = 6; ip6h->priority = 0; */
0433         *(unsigned char *)ip6h = 0x60;
0434         ip6h->flow_lbl[0] = 0;
0435         ip6h->flow_lbl[1] = 0;
0436         ip6h->flow_lbl[2] = 0;
0437
0438         ip6h->payload_len = htons(sizeof(struct udphdr) + len);
0439         ip6h->nexthdr = IPPROTO_UDP;
0440         ip6h->hop_limit = 32;
0441         ip6h->saddr = np->local_ip.in6;
0442         ip6h->daddr = np->remote_ip.in6;
0443
0444         eth = skb_push(skb, ETH_HLEN);
0445         skb_reset_mac_header(skb);
0446         skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
0447     } else {
0448         udph->check = 0;
0449         udph->check = csum_tcpudp_magic(np->local_ip.ip,
0450                         np->remote_ip.ip,
0451                         udp_len, IPPROTO_UDP,
0452                         csum_partial(udph, udp_len, 0));
0453         if (udph->check == 0)
0454             udph->check = CSUM_MANGLED_0;
0455
0456         skb_push(skb, sizeof(*iph));
0457         skb_reset_network_header(skb);
0458         iph = ip_hdr(skb);
0459
0460         /* iph->version = 4; iph->ihl = 5; */
0461         *(unsigned char *)iph = 0x45;
0462         iph->tos      = 0;
0463         put_unaligned(htons(ip_len), &(iph->tot_len));
0464         iph->id       = htons(atomic_inc_return(&ip_ident));
0465         iph->frag_off = 0;
0466         iph->ttl      = 64;
0467         iph->protocol = IPPROTO_UDP;
0468         iph->check    = 0;
0469         put_unaligned(np->local_ip.ip, &(iph->saddr));
0470         put_unaligned(np->remote_ip.ip, &(iph->daddr));
0471         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
0472
0473         eth = skb_push(skb, ETH_HLEN);
0474         skb_reset_mac_header(skb);
0475         skb->protocol = eth->h_proto = htons(ETH_P_IP);
0476     }
0477
0478     ether_addr_copy(eth->h_source, np->dev->dev_addr);
0479     ether_addr_copy(eth->h_dest, np->remote_mac);
0480
0481     skb->dev = np->dev;
0482
0483     netpoll_send_skb(np, skb);
0484 }
0485 EXPORT_SYMBOL(netpoll_send_udp);
0486
0487 void netpoll_print_options(struct netpoll *np)
0488 {
0489     np_info(np, "local port %d\n", np->local_port);
0490     if (np->ipv6)
0491         np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
0492     else
0493         np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
0494     np_info(np, "interface '%s'\n", np->dev_name);
0495     np_info(np, "remote port %d\n", np->remote_port);
0496     if (np->ipv6)
0497         np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
0498     else
0499         np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
0500     np_info(np, "remote ethernet address %pM\n", np->remote_mac);
0501 }
0502 EXPORT_SYMBOL(netpoll_print_options);
0503
0504 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
0505 {
0506     const char *end;
0507
0508     if (!strchr(str, ':') &&
0509         in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
0510         if (!*end)
0511             return 0;
0512     }
0513     if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
0514 #if IS_ENABLED(CONFIG_IPV6)
0515         if (!*end)
0516             return 1;
0517 #else
0518         return -1;
0519 #endif
0520     }
0521     return -1;
0522 }
0523
0524 int netpoll_parse_options(struct netpoll *np, char *opt)
0525 {
0526     char *cur=opt, *delim;
0527     int ipv6;
0528     bool ipversion_set = false;
0529
0530     if (*cur != '@') {
0531         if ((delim = strchr(cur, '@')) == NULL)
0532             goto parse_failed;
0533         *delim = 0;
0534         if (kstrtou16(cur, 10, &np->local_port))
0535             goto parse_failed;
0536         cur = delim;
0537     }
0538     cur++;
0539
0540     if (*cur != '/') {
0541         ipversion_set = true;
0542         if ((delim = strchr(cur, '/')) == NULL)
0543             goto parse_failed;
0544         *delim = 0;
0545         ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
0546         if (ipv6 < 0)
0547             goto parse_failed;
0548         else
0549             np->ipv6 = (bool)ipv6;
0550         cur = delim;
0551     }
0552     cur++;
0553
0554     if (*cur != ',') {
0555         /* parse out dev name */
0556         if ((delim = strchr(cur, ',')) == NULL)
0557             goto parse_failed;
0558         *delim = 0;
0559         strlcpy(np->dev_name, cur, sizeof(np->dev_name));
0560         cur = delim;
0561     }
0562     cur++;
0563
0564     if (*cur != '@') {
0565         /* dst port */
0566         if ((delim = strchr(cur, '@')) == NULL)
0567             goto parse_failed;
0568         *delim = 0;
0569         if (*cur == ' ' || *cur == '\t')
0570             np_info(np, "warning: whitespace is not allowed\n");
0571         if (kstrtou16(cur, 10, &np->remote_port))
0572             goto parse_failed;
0573         cur = delim;
0574     }
0575     cur++;
0576
0577     /* dst ip */
0578     if ((delim = strchr(cur, '/')) == NULL)
0579         goto parse_failed;
0580     *delim = 0;
0581     ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
0582     if (ipv6 < 0)
0583         goto parse_failed;
0584     else if (ipversion_set && np->ipv6 != (bool)ipv6)
0585         goto parse_failed;
0586     else
0587         np->ipv6 = (bool)ipv6;
0588     cur = delim + 1;
0589
0590     if (*cur != 0) {
0591         /* MAC address */
0592         if (!mac_pton(cur, np->remote_mac))
0593             goto parse_failed;
0594     }
0595
0596     netpoll_print_options(np);
0597
0598     return 0;
0599
0600  parse_failed:
0601     np_info(np, "couldn't parse config at '%s'!\n", cur);
0602     return -1;
0603 }
0604 EXPORT_SYMBOL(netpoll_parse_options);
0605
0606 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
0607 {
0608     struct netpoll_info *npinfo;
0609     const struct net_device_ops *ops;
0610     int err;
0611
0612     np->dev = ndev;
0613     strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
0614
0615     if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {
0616         np_err(np, "%s doesn't support polling, aborting\n",
0617                np->dev_name);
0618         err = -ENOTSUPP;
0619         goto out;
0620     }
0621
0622     if (!ndev->npinfo) {
0623         npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
0624         if (!npinfo) {
0625             err = -ENOMEM;
0626             goto out;
0627         }
0628
0629         sema_init(&npinfo->dev_lock, 1);
0630         skb_queue_head_init(&npinfo->txq);
0631         INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
0632
0633         refcount_set(&npinfo->refcnt, 1);
0634
0635         ops = np->dev->netdev_ops;
0636         if (ops->ndo_netpoll_setup) {
0637             err = ops->ndo_netpoll_setup(ndev, npinfo);
0638             if (err)
0639                 goto free_npinfo;
0640         }
0641     } else {
0642         npinfo = rtnl_dereference(ndev->npinfo);
0643         refcount_inc(&npinfo->refcnt);
0644     }
0645
0646     npinfo->netpoll = np;
0647
0648     /* last thing to do is link it to the net device structure */
0649     rcu_assign_pointer(ndev->npinfo, npinfo);
0650
0651     return 0;
0652
0653 free_npinfo:
0654     kfree(npinfo);
0655 out:
0656     return err;
0657 }
0658 EXPORT_SYMBOL_GPL(__netpoll_setup);
0659
0660 int netpoll_setup(struct netpoll *np)
0661 {
0662     struct net_device *ndev = NULL;
0663     struct in_device *in_dev;
0664     int err;
0665
0666     rtnl_lock();
0667     if (np->dev_name[0]) {
0668         struct net *net = current->nsproxy->net_ns;
0669         ndev = __dev_get_by_name(net, np->dev_name);
0670     }
0671     if (!ndev) {
0672         np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
0673         err = -ENODEV;
0674         goto unlock;
0675     }
0676     dev_hold(ndev);
0677
0678     if (netdev_master_upper_dev_get(ndev)) {
0679         np_err(np, "%s is a slave device, aborting\n", np->dev_name);
0680         err = -EBUSY;
0681         goto put;
0682     }
0683
0684     if (!netif_running(ndev)) {
0685         unsigned long atmost, atleast;
0686
0687         np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
0688
0689         err = dev_open(ndev, NULL);
0690
0691         if (err) {
0692             np_err(np, "failed to open %s\n", ndev->name);
0693             goto put;
0694         }
0695
0696         rtnl_unlock();
0697         atleast = jiffies + HZ/10;
0698         atmost = jiffies + carrier_timeout * HZ;
0699         while (!netif_carrier_ok(ndev)) {
0700             if (time_after(jiffies, atmost)) {
0701                 np_notice(np, "timeout waiting for carrier\n");
0702                 break;
0703             }
0704             msleep(1);
0705         }
0706
0707         /* If carrier appears to come up instantly, we don't
0708          * trust it and pause so that we don't pump all our
0709          * queued console messages into the bitbucket.
0710          */
0711
0712         if (time_before(jiffies, atleast)) {
0713             np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
0714             msleep(4000);
0715         }
0716         rtnl_lock();
0717     }
0718
0719     if (!np->local_ip.ip) {
0720         if (!np->ipv6) {
0721             const struct in_ifaddr *ifa;
0722
0723             in_dev = __in_dev_get_rtnl(ndev);
0724             if (!in_dev)
0725                 goto put_noaddr;
0726
0727             ifa = rtnl_dereference(in_dev->ifa_list);
0728             if (!ifa) {
0729 put_noaddr:
0730                 np_err(np, "no IP address for %s, aborting\n",
0731                        np->dev_name);
0732                 err = -EDESTADDRREQ;
0733                 goto put;
0734             }
0735
0736             np->local_ip.ip = ifa->ifa_local;
0737             np_info(np, "local IP %pI4\n", &np->local_ip.ip);
0738         } else {
0739 #if IS_ENABLED(CONFIG_IPV6)
0740             struct inet6_dev *idev;
0741
0742             err = -EDESTADDRREQ;
0743             idev = __in6_dev_get(ndev);
0744             if (idev) {
0745                 struct inet6_ifaddr *ifp;
0746
0747                 read_lock_bh(&idev->lock);
0748                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
0749                     if (!!(ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL) !=
0750                         !!(ipv6_addr_type(&np->remote_ip.in6) & IPV6_ADDR_LINKLOCAL))
0751                         continue;
0752                     np->local_ip.in6 = ifp->addr;
0753                     err = 0;
0754                     break;
0755                 }
0756                 read_unlock_bh(&idev->lock);
0757             }
0758             if (err) {
0759                 np_err(np, "no IPv6 address for %s, aborting\n",
0760                        np->dev_name);
0761                 goto put;
0762             } else
0763                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
0764 #else
0765             np_err(np, "IPv6 is not supported %s, aborting\n",
0766                    np->dev_name);
0767             err = -EINVAL;
0768             goto put;
0769 #endif
0770         }
0771     }
0772
0773     /* fill up the skb queue */
0774     refill_skbs();
0775
0776     err = __netpoll_setup(np, ndev);
0777     if (err)
0778         goto put;
0779     netdev_tracker_alloc(ndev, &np->dev_tracker, GFP_KERNEL);
0780     rtnl_unlock();
0781     return 0;
0782
0783 put:
0784     dev_put(ndev);
0785 unlock:
0786     rtnl_unlock();
0787     return err;
0788 }
0789 EXPORT_SYMBOL(netpoll_setup);
0790
0791 static int __init netpoll_init(void)
0792 {
0793     skb_queue_head_init(&skb_pool);
0794     return 0;
0795 }
0796 core_initcall(netpoll_init);
0797
0798 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
0799 {
0800     struct netpoll_info *npinfo =
0801             container_of(rcu_head, struct netpoll_info, rcu);
0802
0803     skb_queue_purge(&npinfo->txq);
0804
0805     /* we can't call cancel_delayed_work_sync here, as we are in softirq */
0806     cancel_delayed_work(&npinfo->tx_work);
0807
0808     /* clean after last, unfinished work */
0809     __skb_queue_purge(&npinfo->txq);
0810     /* now cancel it again */
0811     cancel_delayed_work(&npinfo->tx_work);
0812     kfree(npinfo);
0813 }
0814
0815 void __netpoll_cleanup(struct netpoll *np)
0816 {
0817     struct netpoll_info *npinfo;
0818
0819     npinfo = rtnl_dereference(np->dev->npinfo);
0820     if (!npinfo)
0821         return;
0822
0823     synchronize_srcu(&netpoll_srcu);
0824
0825     if (refcount_dec_and_test(&npinfo->refcnt)) {
0826         const struct net_device_ops *ops;
0827
0828         ops = np->dev->netdev_ops;
0829         if (ops->ndo_netpoll_cleanup)
0830             ops->ndo_netpoll_cleanup(np->dev);
0831
0832         RCU_INIT_POINTER(np->dev->npinfo, NULL);
0833         call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info);
0834     } else
0835         RCU_INIT_POINTER(np->dev->npinfo, NULL);
0836 }
0837 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
0838
0839 void __netpoll_free(struct netpoll *np)
0840 {
0841     ASSERT_RTNL();
0842
0843     /* Wait for transmitting packets to finish before freeing. */
0844     synchronize_rcu();
0845     __netpoll_cleanup(np);
0846     kfree(np);
0847 }
0848 EXPORT_SYMBOL_GPL(__netpoll_free);
0849
0850 void netpoll_cleanup(struct netpoll *np)
0851 {
0852     rtnl_lock();
0853     if (!np->dev)
0854         goto out;
0855     __netpoll_cleanup(np);
0856     netdev_put(np->dev, &np->dev_tracker);
0857     np->dev = NULL;
0858 out:
0859     rtnl_unlock();
0860 }
0861 EXPORT_SYMBOL(netpoll_cleanup);