// SPDX-License-Identifier: GPL-2.0-only
/*
* Common framework for low-level network console, dump, and debugger code
*
* Sep 8 2003 Matt Mackall <[email protected]>
*
* based on the netconsole code from:
*
* Copyright (C) 2001 Ingo Molnar <[email protected]>
* Copyright (C) 2002 Red Hat, Inc.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/string.h>
#include <linux/if_arp.h>
#include <linux/inetdevice.h>
#include <linux/inet.h>
#include <linux/interrupt.h>
#include <linux/netpoll.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/if_vlan.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/addrconf.h>
#include <net/ndisc.h>
#include <net/ip6_checksum.h>
#include <linux/unaligned.h>
#include <trace/events/napi.h>
#include <linux/kconfig.h>
/*
* We maintain a small pool of fully-sized skbs, to make sure the
* message gets out even in extreme OOM situations.
*/
#define MAX_UDP_CHUNK 1460
#define MAX_SKBS 32
static struct sk_buff_head skb_pool;
#define USEC_PER_POLL 50
#define MAX_SKB_SIZE \
(sizeof(struct ethhdr) + \
sizeof(struct iphdr) + \
sizeof(struct udphdr) + \
MAX_UDP_CHUNK)
static void zap_completion_queue(void);
static unsigned int carrier_timeout = 4;
module_param(carrier_timeout, uint, 0644);
#define np_info(np, fmt, ...) \
pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
#define np_err(np, fmt, ...) \
pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
#define np_notice(np, fmt, ...) \
pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
static netdev_tx_t netpoll_start_xmit(struct sk_buff *skb,
struct net_device *dev,
struct netdev_queue *txq)
{
netdev_tx_t status = NETDEV_TX_OK;
netdev_features_t features;
features = netif_skb_features(skb);
if (skb_vlan_tag_present(skb) &&
!vlan_hw_offload_capable(features, skb->vlan_proto)) {
skb = __vlan_hwaccel_push_inside(skb);
if (unlikely(!skb)) {
/* This is actually a packet drop, but we
* don't want the code that calls this
* function to try and operate on a NULL skb.
*/
goto out;
}
}
status = netdev_start_xmit(skb, dev, txq, false);
out:
return status;
}
static void queue_process(struct work_struct *work)
{
struct netpoll_info *npinfo =
container_of(work, struct netpoll_info, tx_work.work);
struct sk_buff *skb;
unsigned long flags;
while ((skb = skb_dequeue(&npinfo->txq))) {
struct net_device *dev = skb->dev;
struct netdev_queue *txq;
unsigned int q_index;
if (!netif_device_present(dev) || !netif_running(dev)) {
kfree_skb(skb);
continue;
}
local_irq_save(flags);
/* check if skb->queue_mapping is still valid */
q_index = skb_get_queue_mapping(skb);
if (unlikely(q_index >= dev->real_num_tx_queues)) {
q_index = q_index % dev->real_num_tx_queues;
skb_set_queue_mapping(skb, q_index);
}
txq = netdev_get_tx_queue(dev, q_index);
HARD_TX_LOCK(dev, txq, smp_processor_id());
if (netif_xmit_frozen_or_stopped(txq) ||
!dev_xmit_complete(netpoll_start_xmit(skb, dev, txq))) {
skb_queue_head(&npinfo->txq, skb);
HARD_TX_UNLOCK(dev, txq);
local_irq_restore(flags);
schedule_delayed_work(&npinfo->tx_work, HZ/10);
return;
}
HARD_TX_UNLOCK(dev, txq);
local_irq_restore(flags);
}
}
static int netif_local_xmit_active(struct net_device *dev)
{
int i;
for (i = 0; i < dev->num_tx_queues; i++) {
struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
if (READ_ONCE(txq->xmit_lock_owner) == smp_processor_id())
return 1;
}
return 0;
}
static void poll_one_napi(struct napi_struct *napi)
{
int work;
/* If we set this bit but see that it has already been set,
* that indicates that napi has been disabled and we need
* to abort this operation
*/
if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
return;
/* We explicitly pass the polling call a budget of 0 to
* indicate that we are clearing the Tx path only.
*/
work = napi->poll(napi, 0);
WARN_ONCE(work, "%pS exceeded budget in poll\n", napi->poll);
trace_napi_poll(napi, work, 0);
clear_bit(NAPI_STATE_NPSVC, &napi->state);
}
static void poll_napi(struct net_device *dev)
{
struct napi_struct *napi;
int cpu = smp_processor_id();
list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
if (cmpxchg(&napi->poll_owner, -1, cpu) == -1) {
poll_one_napi(napi);
smp_store_release(&napi->poll_owner, -1);
}
}
}
void netpoll_poll_dev(struct net_device *dev)
{
struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
const struct net_device_ops *ops;
/* Don't do any rx activity if the dev_lock mutex is held
* the dev_open/close paths use this to block netpoll activity
* while changing device state
*/
if (!ni || down_trylock(&ni->dev_lock))
return;
/* Some drivers will take the same locks in poll and xmit,
* we can't poll if local CPU is already in xmit.
*/
if (!netif_running(dev) || netif_local_xmit_active(dev)) {
up(&ni->dev_lock);
return;
}
ops = dev->netdev_ops;
if (ops->ndo_poll_controller)
ops->ndo_poll_controller(dev);
poll_napi(dev);
up(&ni->dev_lock);
zap_completion_queue();
}
EXPORT_SYMBOL(netpoll_poll_dev);
void netpoll_poll_disable(struct net_device *dev)
{
struct netpoll_info *ni;
might_sleep();
ni = rtnl_dereference(dev->npinfo);
if (ni)
down(&ni->dev_lock);
}
void netpoll_poll_enable(struct net_device *dev)
{
struct netpoll_info *ni;
ni = rtnl_dereference(dev->npinfo);
if (ni)
up(&ni->dev_lock);
}
static void refill_skbs(void)
{
struct sk_buff *skb;
unsigned long flags;
spin_lock_irqsave(&skb_pool.lock, flags);
while (skb_pool.qlen < MAX_SKBS) {
skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
if (!skb)
break;
__skb_queue_tail(&skb_pool, skb);
}
spin_unlock_irqrestore(&skb_pool.lock, flags);
}
static void zap_completion_queue(void)
{
unsigned long flags;
struct softnet_data *sd = &get_cpu_var(softnet_data);
if (sd->completion_queue) {
struct sk_buff *clist;
local_irq_save(flags);
clist = sd->completion_queue;
sd->completion_queue = NULL;
local_irq_restore(flags);
while (clist != NULL) {
struct sk_buff *skb = clist;
clist = clist->next;
if (!skb_irq_freeable(skb)) {
refcount_set(&skb->users, 1);
dev_kfree_skb_any(skb); /* put this one back */
} else {
__kfree_skb(skb);
}
}
}
put_cpu_var(softnet_data);
}
static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
{
int count = 0;
struct sk_buff *skb;
zap_completion_queue();
refill_skbs();
repeat:
skb = alloc_skb(len, GFP_ATOMIC);
if (!skb)
skb = skb_dequeue(&skb_pool);
if (!skb) {
if (++count < 10) {
netpoll_poll_dev(np->dev);
goto repeat;
}
return NULL;
}
refcount_set(&skb->users, 1);
skb_reserve(skb, reserve);
return skb;
}
static int netpoll_owner_active(struct net_device *dev)
{
struct napi_struct *napi;
list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
if (READ_ONCE(napi->poll_owner) == smp_processor_id())
return 1;
}
return 0;
}
/* call with IRQ disabled */
static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
{
netdev_tx_t status = NETDEV_TX_BUSY;
struct net_device *dev;
unsigned long tries;
/* It is up to the caller to keep npinfo alive. */
struct netpoll_info *npinfo;
lockdep_assert_irqs_disabled();
dev = np->dev;
npinfo = rcu_dereference_bh(dev->npinfo);
if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
dev_kfree_skb_irq(skb);
return NET_XMIT_DROP;
}
/* don't get messages out of order, and no recursion */
if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
struct netdev_queue *txq;
txq = netdev_core_pick_tx(dev, skb, NULL);
/* try until next clock tick */
for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
tries > 0; --tries) {
if (HARD_TX_TRYLOCK(dev, txq)) {
if (!netif_xmit_stopped(txq))
status = netpoll_start_xmit(skb, dev, txq);
HARD_TX_UNLOCK(dev, txq);
if (dev_xmit_complete(status))
break;
}
/* tickle device maybe there is some cleanup */
netpoll_poll_dev(np->dev);
udelay(USEC_PER_POLL);
}
WARN_ONCE(!irqs_disabled(),
"netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pS)\n",
dev->name, dev->netdev_ops->ndo_start_xmit);
}
if (!dev_xmit_complete(status)) {
skb_queue_tail(&npinfo->txq, skb);
schedule_delayed_work(&npinfo->tx_work,0);
}
return NETDEV_TX_OK;
}
netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
{
unsigned long flags;
netdev_tx_t ret;
if (unlikely(!np)) {
dev_kfree_skb_irq(skb);
ret = NET_XMIT_DROP;
} else {
local_irq_save(flags);
ret = __netpoll_send_skb(np, skb);
local_irq_restore(flags);
}
return ret;
}
EXPORT_SYMBOL(netpoll_send_skb);
void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
{
int total_len, ip_len, udp_len;
struct sk_buff *skb;
struct udphdr *udph;
struct iphdr *iph;
struct ethhdr *eth;
static atomic_t ip_ident;
struct ipv6hdr *ip6h;
if (!IS_ENABLED(CONFIG_PREEMPT_RT))
WARN_ON_ONCE(!irqs_disabled());
udp_len = len + sizeof(*udph);
if (np->ipv6)
ip_len = udp_len + sizeof(*ip6h);
else
ip_len = udp_len + sizeof(*iph);
total_len = ip_len + LL_RESERVED_SPACE(np->dev);
skb = find_skb(np, total_len + np->dev->needed_tailroom,
total_len - len);
if (!skb)
return;
skb_copy_to_linear_data(skb, msg, len);
skb_put(skb, len);
skb_push(skb, sizeof(*udph));
skb_reset_transport_header(skb);
udph = udp_hdr(skb);
udph->source = htons(np->local_port);
udph->dest = htons(np->remote_port);
udph->len = htons(udp_len);
if (np->ipv6) {
udph->check = 0;
udph->check = csum_ipv6_magic(&np->local_ip.in6,
&np->remote_ip.in6,
udp_len, IPPROTO_UDP,
csum_partial(udph, udp_len, 0));
if (udph->check == 0)
udph->check = CSUM_MANGLED_0;
skb_push(skb, sizeof(*ip6h));
skb_reset_network_header(skb);
ip6h = ipv6_hdr(skb);
/* ip6h->version = 6; ip6h->priority = 0; */
*(unsigned char *)ip6h = 0x60;
ip6h->flow_lbl[0] = 0;
ip6h->flow_lbl[1] = 0;
ip6h->flow_lbl[2] = 0;
ip6h->payload_len = htons(sizeof(struct udphdr) + len);
ip6h->nexthdr = IPPROTO_UDP;
ip6h->hop_limit = 32;
ip6h->saddr = np->local_ip.in6;
ip6h->daddr = np->remote_ip.in6;
eth = skb_push(skb, ETH_HLEN);
skb_reset_mac_header(skb);
skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
} else {
udph->check = 0;
udph->check = csum_tcpudp_magic(np->local_ip.ip,
np->remote_ip.ip,
udp_len, IPPROTO_UDP,
csum_partial(udph, udp_len, 0));
if (udph->check == 0)
udph->check = CSUM_MANGLED_0;
skb_push(skb, sizeof(*iph));
skb_reset_network_header(skb);
iph = ip_hdr(skb);
/* iph->version = 4; iph->ihl = 5; */
*(unsigned char *)iph = 0x45;
iph->tos = 0;
put_unaligned(htons(ip_len), &(iph->tot_len));
iph->id = htons(atomic_inc_return(&ip_ident));
iph->frag_off = 0;
iph->ttl = 64;
iph->protocol = IPPROTO_UDP;
iph->check = 0;
put_unaligned(np->local_ip.ip, &(iph->saddr));
put_unaligned(np->remote_ip.ip, &(iph->daddr));
iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
eth = skb_push(skb, ETH_HLEN);
skb_reset_mac_header(skb);
skb->protocol = eth->h_proto = htons(ETH_P_IP);
}
ether_addr_copy(eth->h_source, np->dev->dev_addr);
ether_addr_copy(eth->h_dest, np->remote_mac);
skb->dev = np->dev;
netpoll_send_skb(np, skb);
}
EXPORT_SYMBOL(netpoll_send_udp);
void netpoll_print_options(struct netpoll *np)
{
np_info(np, "local port %d\n", np->local_port);
if (np->ipv6)
np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
else
np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
np_info(np, "interface '%s'\n", np->dev_name);
np_info(np, "remote port %d\n", np->remote_port);
if (np->ipv6)
np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
else
np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
np_info(np, "remote ethernet address %pM\n", np->remote_mac);
}
EXPORT_SYMBOL(netpoll_print_options);
static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
{
const char *end;
if (!strchr(str, ':') &&
in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
if (!*end)
return 0;
}
if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
#if IS_ENABLED(CONFIG_IPV6)
if (!*end)
return 1;
#else
return -1;
#endif
}
return -1;
}
int netpoll_parse_options(struct netpoll *np, char *opt)
{
char *cur=opt, *delim;
int ipv6;
bool ipversion_set = false;
if (*cur != '@') {
if ((delim = strchr(cur, '@')) == NULL)
goto parse_failed;
*delim = 0;
if (kstrtou16(cur, 10, &np->local_port))
goto parse_failed;
cur = delim;
}
cur++;
if (*cur != '/') {
ipversion_set = true;
if ((delim = strchr(cur, '/')) == NULL)
goto parse_failed;
*delim = 0;
ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
if (ipv6 < 0)
goto parse_failed;
else
np->ipv6 = (bool)ipv6;
cur = delim;
}
cur++;
if (*cur != ',') {
/* parse out dev name */
if ((delim = strchr(cur, ',')) == NULL)
goto parse_failed;
*delim = 0;
strscpy(np->dev_name, cur, sizeof(np->dev_name));
cur = delim;
}
cur++;
if (*cur != '@') {
/* dst port */
if ((delim = strchr(cur, '@')) == NULL)
goto parse_failed;
*delim = 0;
if (*cur == ' ' || *cur == '\t')
np_info(np, "warning: whitespace is not allowed\n");
if (kstrtou16(cur, 10, &np->remote_port))
goto parse_failed;
cur = delim;
}
cur++;
/* dst ip */
if ((delim = strchr(cur, '/')) == NULL)
goto parse_failed;
*delim = 0;
ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
if (ipv6 < 0)
goto parse_failed;
else if (ipversion_set && np->ipv6 != (bool)ipv6)
goto parse_failed;
else
np->ipv6 = (bool)ipv6;
cur = delim + 1;
if (*cur != 0) {
/* MAC address */
if (!mac_pton(cur, np->remote_mac))
goto parse_failed;
}
netpoll_print_options(np);
return 0;
parse_failed:
np_info(np, "couldn't parse config at '%s'!\n", cur);
return -1;
}
EXPORT_SYMBOL(netpoll_parse_options);
int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
{
struct netpoll_info *npinfo;
const struct net_device_ops *ops;
int err;
if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {
np_err(np, "%s doesn't support polling, aborting\n",
ndev->name);
err = -ENOTSUPP;
goto out;
}
if (!ndev->npinfo) {
npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
if (!npinfo) {
err = -ENOMEM;
goto out;
}
sema_init(&npinfo->dev_lock, 1);
skb_queue_head_init(&npinfo->txq);
INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
refcount_set(&npinfo->refcnt, 1);
ops = ndev->netdev_ops;
if (ops->ndo_netpoll_setup) {
err = ops->ndo_netpoll_setup(ndev, npinfo);
if (err)
goto free_npinfo;
}
} else {
npinfo = rtnl_dereference(ndev->npinfo);
refcount_inc(&npinfo->refcnt);
}
np->dev = ndev;
strscpy(np->dev_name, ndev->name, IFNAMSIZ);
npinfo->netpoll = np;
/* last thing to do is link it to the net device structure */
rcu_assign_pointer(ndev->npinfo, npinfo);
return 0;
free_npinfo:
kfree(npinfo);
out:
return err;
}
EXPORT_SYMBOL_GPL(__netpoll_setup);
int netpoll_setup(struct netpoll *np)
{
struct net_device *ndev = NULL;
bool ip_overwritten = false;
struct in_device *in_dev;
int err;
rtnl_lock();
if (np->dev_name[0]) {
struct net *net = current->nsproxy->net_ns;
ndev = __dev_get_by_name(net, np->dev_name);
}
if (!ndev) {
np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
err = -ENODEV;
goto unlock;
}
netdev_hold(ndev, &np->dev_tracker, GFP_KERNEL);
if (netdev_master_upper_dev_get(ndev)) {
np_err(np, "%s is a slave device, aborting\n", np->dev_name);
err = -EBUSY;
goto put;
}
if (!netif_running(ndev)) {
unsigned long atmost;
np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
err = dev_open(ndev, NULL);
if (err) {
np_err(np, "failed to open %s\n", ndev->name);
goto put;
}
rtnl_unlock();
atmost = jiffies + carrier_timeout * HZ;
while (!netif_carrier_ok(ndev)) {
if (time_after(jiffies, atmost)) {
np_notice(np, "timeout waiting for carrier\n");
break;
}
msleep(1);
}
rtnl_lock();
}
if (!np->local_ip.ip) {
if (!np->ipv6) {
const struct in_ifaddr *ifa;
in_dev = __in_dev_get_rtnl(ndev);
if (!in_dev)
goto put_noaddr;
ifa = rtnl_dereference(in_dev->ifa_list);
if (!ifa) {
put_noaddr:
np_err(np, "no IP address for %s, aborting\n",
np->dev_name);
err = -EDESTADDRREQ;
goto put;
}
np->local_ip.ip = ifa->ifa_local;
ip_overwritten = true;
np_info(np, "local IP %pI4\n", &np->local_ip.ip);
} else {
#if IS_ENABLED(CONFIG_IPV6)
struct inet6_dev *idev;
err = -EDESTADDRREQ;
idev = __in6_dev_get(ndev);
if (idev) {
struct inet6_ifaddr *ifp;
read_lock_bh(&idev->lock);
list_for_each_entry(ifp, &idev->addr_list, if_list) {
if (!!(ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL) !=
!!(ipv6_addr_type(&np->remote_ip.in6) & IPV6_ADDR_LINKLOCAL))
continue;
np->local_ip.in6 = ifp->addr;
ip_overwritten = true;
err = 0;
break;
}
read_unlock_bh(&idev->lock);
}
if (err) {
np_err(np, "no IPv6 address for %s, aborting\n",
np->dev_name);
goto put;
} else
np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
#else
np_err(np, "IPv6 is not supported %s, aborting\n",
np->dev_name);
err = -EINVAL;
goto put;
#endif
}
}
/* fill up the skb queue */
refill_skbs();
err = __netpoll_setup(np, ndev);
if (err)
goto put;
rtnl_unlock();
return 0;
put:
DEBUG_NET_WARN_ON_ONCE(np->dev);
if (ip_overwritten)
memset(&np->local_ip, 0, sizeof(np->local_ip));
netdev_put(ndev, &np->dev_tracker);
unlock:
rtnl_unlock();
return err;
}
EXPORT_SYMBOL(netpoll_setup);
static int __init netpoll_init(void)
{
skb_queue_head_init(&skb_pool);
return 0;
}
core_initcall(netpoll_init);
static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
{
struct netpoll_info *npinfo =
container_of(rcu_head, struct netpoll_info, rcu);
skb_queue_purge(&npinfo->txq);
/* we can't call cancel_delayed_work_sync here, as we are in softirq */
cancel_delayed_work(&npinfo->tx_work);
/* clean after last, unfinished work */
__skb_queue_purge(&npinfo->txq);
/* now cancel it again */
cancel_delayed_work(&npinfo->tx_work);
kfree(npinfo);
}
void __netpoll_cleanup(struct netpoll *np)
{
struct netpoll_info *npinfo;
npinfo = rtnl_dereference(np->dev->npinfo);
if (!npinfo)
return;
if (refcount_dec_and_test(&npinfo->refcnt)) {
const struct net_device_ops *ops;
ops = np->dev->netdev_ops;
if (ops->ndo_netpoll_cleanup)
ops->ndo_netpoll_cleanup(np->dev);
RCU_INIT_POINTER(np->dev->npinfo, NULL);
call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info);
} else
RCU_INIT_POINTER(np->dev->npinfo, NULL);
}
EXPORT_SYMBOL_GPL(__netpoll_cleanup);
void __netpoll_free(struct netpoll *np)
{
ASSERT_RTNL();
/* Wait for transmitting packets to finish before freeing. */
synchronize_rcu();
__netpoll_cleanup(np);
kfree(np);
}
EXPORT_SYMBOL_GPL(__netpoll_free);
void do_netpoll_cleanup(struct netpoll *np)
{
__netpoll_cleanup(np);
netdev_put(np->dev, &np->dev_tracker);
np->dev = NULL;
}
EXPORT_SYMBOL(do_netpoll_cleanup);
void netpoll_cleanup(struct netpoll *np)
{
rtnl_lock();
if (!np->dev)
goto out;
do_netpoll_cleanup(np);
out:
rtnl_unlock();
}
EXPORT_SYMBOL(netpoll_cleanup);
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