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drop_monitor.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Monitoring code for network dropped packet alerts
*
* Copyright (C) 2009 Neil Horman <[email protected]>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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/types.h>
#include <linux/workqueue.h>
#include <linux/netlink.h>
#include <linux/net_dropmon.h>
#include <linux/percpu.h>
#include <linux/timer.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <net/drop_monitor.h>
#include <net/genetlink.h>
#include <net/netevent.h>
#include <trace/events/skb.h>
#include <trace/events/napi.h>
#include <asm/unaligned.h>
#define TRACE_ON 1
#define TRACE_OFF 0
/*
* Globals, our netlink socket pointer
* and the work handle that will send up
* netlink alerts
*/
static int trace_state = TRACE_OFF;
static bool monitor_hw;
/* net_dm_mutex
*
* An overall lock guarding every operation coming from userspace.
* It also guards the global 'hw_stats_list' list.
*/
static DEFINE_MUTEX(net_dm_mutex);
struct net_dm_stats {
u64 dropped;
struct u64_stats_sync syncp;
};
#define NET_DM_MAX_HW_TRAP_NAME_LEN 40
struct net_dm_hw_entry {
char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
u32 count;
};
struct net_dm_hw_entries {
u32 num_entries;
struct net_dm_hw_entry entries[0];
};
struct per_cpu_dm_data {
spinlock_t lock; /* Protects 'skb', 'hw_entries' and
* 'send_timer'
*/
union {
struct sk_buff *skb;
struct net_dm_hw_entries *hw_entries;
};
struct sk_buff_head drop_queue;
struct work_struct dm_alert_work;
struct timer_list send_timer;
struct net_dm_stats stats;
};
struct dm_hw_stat_delta {
struct net_device *dev;
unsigned long last_rx;
struct list_head list;
struct rcu_head rcu;
unsigned long last_drop_val;
};
static struct genl_family net_drop_monitor_family;
static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
static int dm_hit_limit = 64;
static int dm_delay = 1;
static unsigned long dm_hw_check_delta = 2*HZ;
static LIST_HEAD(hw_stats_list);
static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
static u32 net_dm_trunc_len;
static u32 net_dm_queue_len = 1000;
struct net_dm_alert_ops {
void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
void *location);
void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
int work, int budget);
void (*work_item_func)(struct work_struct *work);
void (*hw_work_item_func)(struct work_struct *work);
void (*hw_probe)(struct sk_buff *skb,
const struct net_dm_hw_metadata *hw_metadata);
};
struct net_dm_skb_cb {
union {
struct net_dm_hw_metadata *hw_metadata;
void *pc;
};
};
#define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
{
size_t al;
struct net_dm_alert_msg *msg;
struct nlattr *nla;
struct sk_buff *skb;
unsigned long flags;
void *msg_header;
al = sizeof(struct net_dm_alert_msg);
al += dm_hit_limit * sizeof(struct net_dm_drop_point);
al += sizeof(struct nlattr);
skb = genlmsg_new(al, GFP_KERNEL);
if (!skb)
goto err;
msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
0, NET_DM_CMD_ALERT);
if (!msg_header) {
nlmsg_free(skb);
skb = NULL;
goto err;
}
nla = nla_reserve(skb, NLA_UNSPEC,
sizeof(struct net_dm_alert_msg));
if (!nla) {
nlmsg_free(skb);
skb = NULL;
goto err;
}
msg = nla_data(nla);
memset(msg, 0, al);
goto out;
err:
mod_timer(&data->send_timer, jiffies + HZ / 10);
out:
spin_lock_irqsave(&data->lock, flags);
swap(data->skb, skb);
spin_unlock_irqrestore(&data->lock, flags);
if (skb) {
struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
genlmsg_end(skb, genlmsg_data(gnlh));
}
return skb;
}
static const struct genl_multicast_group dropmon_mcgrps[] = {
{ .name = "events", },
};
static void send_dm_alert(struct work_struct *work)
{
struct sk_buff *skb;
struct per_cpu_dm_data *data;
data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
skb = reset_per_cpu_data(data);
if (skb)
genlmsg_multicast(&net_drop_monitor_family, skb, 0,
0, GFP_KERNEL);
}
/*
* This is the timer function to delay the sending of an alert
* in the event that more drops will arrive during the
* hysteresis period.
*/
static void sched_send_work(struct timer_list *t)
{
struct per_cpu_dm_data *data = from_timer(data, t, send_timer);
schedule_work(&data->dm_alert_work);
}
static void trace_drop_common(struct sk_buff *skb, void *location)
{
struct net_dm_alert_msg *msg;
struct nlmsghdr *nlh;
struct nlattr *nla;
int i;
struct sk_buff *dskb;
struct per_cpu_dm_data *data;
unsigned long flags;
local_irq_save(flags);
data = this_cpu_ptr(&dm_cpu_data);
spin_lock(&data->lock);
dskb = data->skb;
if (!dskb)
goto out;
nlh = (struct nlmsghdr *)dskb->data;
nla = genlmsg_data(nlmsg_data(nlh));
msg = nla_data(nla);
for (i = 0; i < msg->entries; i++) {
if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
msg->points[i].count++;
goto out;
}
}
if (msg->entries == dm_hit_limit)
goto out;
/*
* We need to create a new entry
*/
__nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
msg->points[msg->entries].count = 1;
msg->entries++;
if (!timer_pending(&data->send_timer)) {
data->send_timer.expires = jiffies + dm_delay * HZ;
add_timer(&data->send_timer);
}
out:
spin_unlock_irqrestore(&data->lock, flags);
}
static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location)
{
trace_drop_common(skb, location);
}
static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
int work, int budget)
{
struct dm_hw_stat_delta *new_stat;
/*
* Don't check napi structures with no associated device
*/
if (!napi->dev)
return;
rcu_read_lock();
list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
/*
* only add a note to our monitor buffer if:
* 1) this is the dev we received on
* 2) its after the last_rx delta
* 3) our rx_dropped count has gone up
*/
if ((new_stat->dev == napi->dev) &&
(time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) &&
(napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
trace_drop_common(NULL, NULL);
new_stat->last_drop_val = napi->dev->stats.rx_dropped;
new_stat->last_rx = jiffies;
break;
}
}
rcu_read_unlock();
}
static struct net_dm_hw_entries *
net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
{
struct net_dm_hw_entries *hw_entries;
unsigned long flags;
hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
GFP_KERNEL);
if (!hw_entries) {
/* If the memory allocation failed, we try to perform another
* allocation in 1/10 second. Otherwise, the probe function
* will constantly bail out.
*/
mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
}
spin_lock_irqsave(&hw_data->lock, flags);
swap(hw_data->hw_entries, hw_entries);
spin_unlock_irqrestore(&hw_data->lock, flags);
return hw_entries;
}
static int net_dm_hw_entry_put(struct sk_buff *msg,
const struct net_dm_hw_entry *hw_entry)
{
struct nlattr *attr;
attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
if (!attr)
return -EMSGSIZE;
if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
goto nla_put_failure;
if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
goto nla_put_failure;
nla_nest_end(msg, attr);
return 0;
nla_put_failure:
nla_nest_cancel(msg, attr);
return -EMSGSIZE;
}
static int net_dm_hw_entries_put(struct sk_buff *msg,
const struct net_dm_hw_entries *hw_entries)
{
struct nlattr *attr;
int i;
attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
if (!attr)
return -EMSGSIZE;
for (i = 0; i < hw_entries->num_entries; i++) {
int rc;
rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
if (rc)
goto nla_put_failure;
}
nla_nest_end(msg, attr);
return 0;
nla_put_failure:
nla_nest_cancel(msg, attr);
return -EMSGSIZE;
}
static int
net_dm_hw_summary_report_fill(struct sk_buff *msg,
const struct net_dm_hw_entries *hw_entries)
{
struct net_dm_alert_msg anc_hdr = { 0 };
void *hdr;
int rc;
hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
NET_DM_CMD_ALERT);
if (!hdr)
return -EMSGSIZE;
/* We need to put the ancillary header in order not to break user
* space.
*/
if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
goto nla_put_failure;
rc = net_dm_hw_entries_put(msg, hw_entries);
if (rc)
goto nla_put_failure;
genlmsg_end(msg, hdr);
return 0;
nla_put_failure:
genlmsg_cancel(msg, hdr);
return -EMSGSIZE;
}
static void net_dm_hw_summary_work(struct work_struct *work)
{
struct net_dm_hw_entries *hw_entries;
struct per_cpu_dm_data *hw_data;
struct sk_buff *msg;
int rc;
hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
if (!hw_entries)
return;
msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (!msg)
goto out;
rc = net_dm_hw_summary_report_fill(msg, hw_entries);
if (rc) {
nlmsg_free(msg);
goto out;
}
genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
out:
kfree(hw_entries);
}
static void
net_dm_hw_summary_probe(struct sk_buff *skb,
const struct net_dm_hw_metadata *hw_metadata)
{
struct net_dm_hw_entries *hw_entries;
struct net_dm_hw_entry *hw_entry;
struct per_cpu_dm_data *hw_data;
unsigned long flags;
int i;
hw_data = this_cpu_ptr(&dm_hw_cpu_data);
spin_lock_irqsave(&hw_data->lock, flags);
hw_entries = hw_data->hw_entries;
if (!hw_entries)
goto out;
for (i = 0; i < hw_entries->num_entries; i++) {
hw_entry = &hw_entries->entries[i];
if (!strncmp(hw_entry->trap_name, hw_metadata->trap_name,
NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
hw_entry->count++;
goto out;
}
}
if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
goto out;
hw_entry = &hw_entries->entries[hw_entries->num_entries];
strlcpy(hw_entry->trap_name, hw_metadata->trap_name,
NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
hw_entry->count = 1;
hw_entries->num_entries++;
if (!timer_pending(&hw_data->send_timer)) {
hw_data->send_timer.expires = jiffies + dm_delay * HZ;
add_timer(&hw_data->send_timer);
}
out:
spin_unlock_irqrestore(&hw_data->lock, flags);
}
static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
.kfree_skb_probe = trace_kfree_skb_hit,
.napi_poll_probe = trace_napi_poll_hit,
.work_item_func = send_dm_alert,
.hw_work_item_func = net_dm_hw_summary_work,
.hw_probe = net_dm_hw_summary_probe,
};
static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
struct sk_buff *skb,
void *location)
{
ktime_t tstamp = ktime_get_real();
struct per_cpu_dm_data *data;
struct sk_buff *nskb;
unsigned long flags;
if (!skb_mac_header_was_set(skb))
return;
nskb = skb_clone(skb, GFP_ATOMIC);
if (!nskb)
return;
NET_DM_SKB_CB(nskb)->pc = location;
/* Override the timestamp because we care about the time when the
* packet was dropped.
*/
nskb->tstamp = tstamp;
data = this_cpu_ptr(&dm_cpu_data);
spin_lock_irqsave(&data->drop_queue.lock, flags);
if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
__skb_queue_tail(&data->drop_queue, nskb);
else
goto unlock_free;
spin_unlock_irqrestore(&data->drop_queue.lock, flags);
schedule_work(&data->dm_alert_work);
return;
unlock_free:
spin_unlock_irqrestore(&data->drop_queue.lock, flags);
u64_stats_update_begin(&data->stats.syncp);
data->stats.dropped++;
u64_stats_update_end(&data->stats.syncp);
consume_skb(nskb);
}
static void net_dm_packet_trace_napi_poll_hit(void *ignore,
struct napi_struct *napi,
int work, int budget)
{
}
static size_t net_dm_in_port_size(void)
{
/* NET_DM_ATTR_IN_PORT nest */
return nla_total_size(0) +
/* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
nla_total_size(sizeof(u32)) +
/* NET_DM_ATTR_PORT_NETDEV_NAME */
nla_total_size(IFNAMSIZ + 1);
}
#define NET_DM_MAX_SYMBOL_LEN 40
static size_t net_dm_packet_report_size(size_t payload_len)
{
size_t size;
size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
return NLMSG_ALIGN(size) +
/* NET_DM_ATTR_ORIGIN */
nla_total_size(sizeof(u16)) +
/* NET_DM_ATTR_PC */
nla_total_size(sizeof(u64)) +
/* NET_DM_ATTR_SYMBOL */
nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
/* NET_DM_ATTR_IN_PORT */
net_dm_in_port_size() +
/* NET_DM_ATTR_TIMESTAMP */
nla_total_size(sizeof(u64)) +
/* NET_DM_ATTR_ORIG_LEN */
nla_total_size(sizeof(u32)) +
/* NET_DM_ATTR_PROTO */
nla_total_size(sizeof(u16)) +
/* NET_DM_ATTR_PAYLOAD */
nla_total_size(payload_len);
}
static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
const char *name)
{
struct nlattr *attr;
attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
if (!attr)
return -EMSGSIZE;
if (ifindex &&
nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
goto nla_put_failure;
if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
goto nla_put_failure;
nla_nest_end(msg, attr);
return 0;
nla_put_failure:
nla_nest_cancel(msg, attr);
return -EMSGSIZE;
}
static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
size_t payload_len)
{
u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc;
char buf[NET_DM_MAX_SYMBOL_LEN];
struct nlattr *attr;
void *hdr;
int rc;
hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
NET_DM_CMD_PACKET_ALERT);
if (!hdr)
return -EMSGSIZE;
if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
goto nla_put_failure;
if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD))
goto nla_put_failure;
snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc);
if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
goto nla_put_failure;
rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
if (rc)
goto nla_put_failure;
if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
goto nla_put_failure;
if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
goto nla_put_failure;
if (!payload_len)
goto out;
if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
goto nla_put_failure;
attr = skb_put(msg, nla_total_size(payload_len));
attr->nla_type = NET_DM_ATTR_PAYLOAD;
attr->nla_len = nla_attr_size(payload_len);
if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
goto nla_put_failure;
out:
genlmsg_end(msg, hdr);
return 0;
nla_put_failure:
genlmsg_cancel(msg, hdr);
return -EMSGSIZE;
}
#define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
static void net_dm_packet_report(struct sk_buff *skb)
{
struct sk_buff *msg;
size_t payload_len;
int rc;
/* Make sure we start copying the packet from the MAC header */
if (skb->data > skb_mac_header(skb))
skb_push(skb, skb->data - skb_mac_header(skb));
else
skb_pull(skb, skb_mac_header(skb) - skb->data);
/* Ensure packet fits inside a single netlink attribute */
payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
if (net_dm_trunc_len)
payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
if (!msg)
goto out;
rc = net_dm_packet_report_fill(msg, skb, payload_len);
if (rc) {
nlmsg_free(msg);
goto out;
}
genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
out:
consume_skb(skb);
}
static void net_dm_packet_work(struct work_struct *work)
{
struct per_cpu_dm_data *data;
struct sk_buff_head list;
struct sk_buff *skb;
unsigned long flags;
data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
__skb_queue_head_init(&list);
spin_lock_irqsave(&data->drop_queue.lock, flags);
skb_queue_splice_tail_init(&data->drop_queue, &list);
spin_unlock_irqrestore(&data->drop_queue.lock, flags);
while ((skb = __skb_dequeue(&list)))
net_dm_packet_report(skb);
}
static size_t
net_dm_hw_packet_report_size(size_t payload_len,
const struct net_dm_hw_metadata *hw_metadata)
{
size_t size;
size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
return NLMSG_ALIGN(size) +
/* NET_DM_ATTR_ORIGIN */
nla_total_size(sizeof(u16)) +
/* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
/* NET_DM_ATTR_HW_TRAP_NAME */
nla_total_size(strlen(hw_metadata->trap_name) + 1) +
/* NET_DM_ATTR_IN_PORT */
net_dm_in_port_size() +
/* NET_DM_ATTR_TIMESTAMP */
nla_total_size(sizeof(u64)) +
/* NET_DM_ATTR_ORIG_LEN */
nla_total_size(sizeof(u32)) +
/* NET_DM_ATTR_PROTO */
nla_total_size(sizeof(u16)) +
/* NET_DM_ATTR_PAYLOAD */
nla_total_size(payload_len);
}
static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
struct sk_buff *skb, size_t payload_len)
{
struct net_dm_hw_metadata *hw_metadata;
struct nlattr *attr;
void *hdr;
hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
NET_DM_CMD_PACKET_ALERT);
if (!hdr)
return -EMSGSIZE;
if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
goto nla_put_failure;
if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
hw_metadata->trap_group_name))
goto nla_put_failure;
if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
hw_metadata->trap_name))
goto nla_put_failure;
if (hw_metadata->input_dev) {
struct net_device *dev = hw_metadata->input_dev;
int rc;
rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
dev->name);
if (rc)
goto nla_put_failure;
}
if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
goto nla_put_failure;
if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
goto nla_put_failure;
if (!payload_len)
goto out;
if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
goto nla_put_failure;
attr = skb_put(msg, nla_total_size(payload_len));
attr->nla_type = NET_DM_ATTR_PAYLOAD;
attr->nla_len = nla_attr_size(payload_len);
if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
goto nla_put_failure;
out:
genlmsg_end(msg, hdr);
return 0;
nla_put_failure:
genlmsg_cancel(msg, hdr);
return -EMSGSIZE;
}
static struct net_dm_hw_metadata *
net_dm_hw_metadata_clone(const struct net_dm_hw_metadata *hw_metadata)
{
struct net_dm_hw_metadata *n_hw_metadata;
const char *trap_group_name;
const char *trap_name;
n_hw_metadata = kmalloc(sizeof(*hw_metadata), GFP_ATOMIC);
if (!n_hw_metadata)
return NULL;
trap_group_name = kmemdup(hw_metadata->trap_group_name,
strlen(hw_metadata->trap_group_name) + 1,
GFP_ATOMIC | __GFP_ZERO);
if (!trap_group_name)
goto free_hw_metadata;
n_hw_metadata->trap_group_name = trap_group_name;
trap_name = kmemdup(hw_metadata->trap_name,
strlen(hw_metadata->trap_name) + 1,
GFP_ATOMIC | __GFP_ZERO);
if (!trap_name)
goto free_trap_group;
n_hw_metadata->trap_name = trap_name;
n_hw_metadata->input_dev = hw_metadata->input_dev;
if (n_hw_metadata->input_dev)
dev_hold(n_hw_metadata->input_dev);
return n_hw_metadata;
free_trap_group:
kfree(trap_group_name);
free_hw_metadata:
kfree(n_hw_metadata);
return NULL;
}
static void
net_dm_hw_metadata_free(const struct net_dm_hw_metadata *hw_metadata)
{
if (hw_metadata->input_dev)
dev_put(hw_metadata->input_dev);
kfree(hw_metadata->trap_name);
kfree(hw_metadata->trap_group_name);
kfree(hw_metadata);
}
static void net_dm_hw_packet_report(struct sk_buff *skb)
{
struct net_dm_hw_metadata *hw_metadata;
struct sk_buff *msg;
size_t payload_len;
int rc;
if (skb->data > skb_mac_header(skb))
skb_push(skb, skb->data - skb_mac_header(skb));
else
skb_pull(skb, skb_mac_header(skb) - skb->data);
payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
if (net_dm_trunc_len)
payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
GFP_KERNEL);
if (!msg)
goto out;
rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
if (rc) {
nlmsg_free(msg);
goto out;
}
genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
out:
net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
consume_skb(skb);
}
static void net_dm_hw_packet_work(struct work_struct *work)
{
struct per_cpu_dm_data *hw_data;
struct sk_buff_head list;
struct sk_buff *skb;
unsigned long flags;
hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
__skb_queue_head_init(&list);
spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
while ((skb = __skb_dequeue(&list)))
net_dm_hw_packet_report(skb);
}
static void
net_dm_hw_packet_probe(struct sk_buff *skb,
const struct net_dm_hw_metadata *hw_metadata)
{
struct net_dm_hw_metadata *n_hw_metadata;
ktime_t tstamp = ktime_get_real();
struct per_cpu_dm_data *hw_data;
struct sk_buff *nskb;
unsigned long flags;
if (!skb_mac_header_was_set(skb))
return;
nskb = skb_clone(skb, GFP_ATOMIC);
if (!nskb)
return;
n_hw_metadata = net_dm_hw_metadata_clone(hw_metadata);
if (!n_hw_metadata)
goto free;
NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
nskb->tstamp = tstamp;
hw_data = this_cpu_ptr(&dm_hw_cpu_data);
spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
__skb_queue_tail(&hw_data->drop_queue, nskb);
else
goto unlock_free;
spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
schedule_work(&hw_data->dm_alert_work);
return;
unlock_free:
spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
u64_stats_update_begin(&hw_data->stats.syncp);
hw_data->stats.dropped++;
u64_stats_update_end(&hw_data->stats.syncp);
net_dm_hw_metadata_free(n_hw_metadata);
free:
consume_skb(nskb);
}
static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
.kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit,
.napi_poll_probe = net_dm_packet_trace_napi_poll_hit,
.work_item_func = net_dm_packet_work,
.hw_work_item_func = net_dm_hw_packet_work,
.hw_probe = net_dm_hw_packet_probe,
};
static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
[NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops,
[NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops,
};
void net_dm_hw_report(struct sk_buff *skb,
const struct net_dm_hw_metadata *hw_metadata)
{
rcu_read_lock();
if (!monitor_hw)
goto out;
net_dm_alert_ops_arr[net_dm_alert_mode]->hw_probe(skb, hw_metadata);
out:
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(net_dm_hw_report);
static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
{
const struct net_dm_alert_ops *ops;
int cpu;
if (monitor_hw) {
NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
return -EAGAIN;
}
ops = net_dm_alert_ops_arr[net_dm_alert_mode];
if (!try_module_get(THIS_MODULE)) {
NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
return -ENODEV;
}
for_each_possible_cpu(cpu) {
struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
struct net_dm_hw_entries *hw_entries;
INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
timer_setup(&hw_data->send_timer, sched_send_work, 0);
hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
kfree(hw_entries);
}
monitor_hw = true;
return 0;