397 lines
8.7 KiB
C
397 lines
8.7 KiB
C
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/*
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* Monitoring code for network dropped packet alerts
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*
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* Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
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*/
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/string.h>
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#include <linux/if_arp.h>
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#include <linux/inetdevice.h>
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#include <linux/inet.h>
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#include <linux/interrupt.h>
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#include <linux/netpoll.h>
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#include <linux/sched.h>
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#include <linux/delay.h>
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#include <linux/types.h>
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#include <linux/workqueue.h>
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#include <linux/netlink.h>
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#include <linux/net_dropmon.h>
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#include <linux/percpu.h>
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#include <linux/timer.h>
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#include <linux/bitops.h>
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#include <net/genetlink.h>
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#include <net/netevent.h>
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#include <trace/events/skb.h>
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#include <trace/events/napi.h>
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#include <asm/unaligned.h>
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#define TRACE_ON 1
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#define TRACE_OFF 0
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static void send_dm_alert(struct work_struct *unused);
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/*
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* Globals, our netlink socket pointer
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* and the work handle that will send up
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* netlink alerts
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*/
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static int trace_state = TRACE_OFF;
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static spinlock_t trace_state_lock = SPIN_LOCK_UNLOCKED;
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struct per_cpu_dm_data {
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struct work_struct dm_alert_work;
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struct sk_buff *skb;
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atomic_t dm_hit_count;
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struct timer_list send_timer;
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};
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struct dm_hw_stat_delta {
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struct net_device *dev;
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unsigned long last_rx;
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struct list_head list;
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struct rcu_head rcu;
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unsigned long last_drop_val;
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};
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static struct genl_family net_drop_monitor_family = {
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.id = GENL_ID_GENERATE,
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.hdrsize = 0,
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.name = "NET_DM",
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.version = 2,
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.maxattr = NET_DM_CMD_MAX,
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};
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static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
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static int dm_hit_limit = 64;
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static int dm_delay = 1;
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static unsigned long dm_hw_check_delta = 2*HZ;
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static LIST_HEAD(hw_stats_list);
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static void reset_per_cpu_data(struct per_cpu_dm_data *data)
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{
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size_t al;
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struct net_dm_alert_msg *msg;
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struct nlattr *nla;
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al = sizeof(struct net_dm_alert_msg);
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al += dm_hit_limit * sizeof(struct net_dm_drop_point);
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al += sizeof(struct nlattr);
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data->skb = genlmsg_new(al, GFP_KERNEL);
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genlmsg_put(data->skb, 0, 0, &net_drop_monitor_family,
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0, NET_DM_CMD_ALERT);
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nla = nla_reserve(data->skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg));
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msg = nla_data(nla);
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memset(msg, 0, al);
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atomic_set(&data->dm_hit_count, dm_hit_limit);
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}
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static void send_dm_alert(struct work_struct *unused)
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{
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struct sk_buff *skb;
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struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
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/*
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* Grab the skb we're about to send
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*/
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skb = data->skb;
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/*
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* Replace it with a new one
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*/
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reset_per_cpu_data(data);
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/*
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* Ship it!
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*/
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genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
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}
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/*
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* This is the timer function to delay the sending of an alert
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* in the event that more drops will arrive during the
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* hysteresis period. Note that it operates under the timer interrupt
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* so we don't need to disable preemption here
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*/
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static void sched_send_work(unsigned long unused)
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{
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struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
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schedule_work(&data->dm_alert_work);
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}
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static void trace_drop_common(struct sk_buff *skb, void *location)
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{
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struct net_dm_alert_msg *msg;
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struct nlmsghdr *nlh;
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struct nlattr *nla;
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int i;
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struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
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if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) {
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/*
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* we're already at zero, discard this hit
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*/
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goto out;
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}
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nlh = (struct nlmsghdr *)data->skb->data;
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nla = genlmsg_data(nlmsg_data(nlh));
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msg = nla_data(nla);
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for (i = 0; i < msg->entries; i++) {
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if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
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msg->points[i].count++;
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goto out;
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}
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}
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/*
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* We need to create a new entry
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*/
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__nla_reserve_nohdr(data->skb, sizeof(struct net_dm_drop_point));
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nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
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memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
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msg->points[msg->entries].count = 1;
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msg->entries++;
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if (!timer_pending(&data->send_timer)) {
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data->send_timer.expires = jiffies + dm_delay * HZ;
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add_timer_on(&data->send_timer, smp_processor_id());
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}
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out:
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return;
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}
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static void trace_kfree_skb_hit(struct sk_buff *skb, void *location)
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{
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trace_drop_common(skb, location);
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}
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static void trace_napi_poll_hit(struct napi_struct *napi)
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{
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struct dm_hw_stat_delta *new_stat;
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/*
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* Don't check napi structures with no associated device
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*/
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if (!napi->dev)
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return;
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rcu_read_lock();
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list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
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/*
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* only add a note to our monitor buffer if:
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* 1) this is the dev we received on
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* 2) its after the last_rx delta
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* 3) our rx_dropped count has gone up
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*/
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if ((new_stat->dev == napi->dev) &&
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(time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) &&
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(napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
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trace_drop_common(NULL, NULL);
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new_stat->last_drop_val = napi->dev->stats.rx_dropped;
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new_stat->last_rx = jiffies;
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break;
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}
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}
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rcu_read_unlock();
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}
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static void free_dm_hw_stat(struct rcu_head *head)
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{
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struct dm_hw_stat_delta *n;
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n = container_of(head, struct dm_hw_stat_delta, rcu);
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kfree(n);
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}
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static int set_all_monitor_traces(int state)
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{
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int rc = 0;
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struct dm_hw_stat_delta *new_stat = NULL;
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struct dm_hw_stat_delta *temp;
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spin_lock(&trace_state_lock);
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switch (state) {
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case TRACE_ON:
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rc |= register_trace_kfree_skb(trace_kfree_skb_hit);
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rc |= register_trace_napi_poll(trace_napi_poll_hit);
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break;
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case TRACE_OFF:
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rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit);
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rc |= unregister_trace_napi_poll(trace_napi_poll_hit);
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tracepoint_synchronize_unregister();
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/*
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* Clean the device list
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*/
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list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
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if (new_stat->dev == NULL) {
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list_del_rcu(&new_stat->list);
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call_rcu(&new_stat->rcu, free_dm_hw_stat);
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}
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}
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break;
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default:
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rc = 1;
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break;
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}
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if (!rc)
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trace_state = state;
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spin_unlock(&trace_state_lock);
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if (rc)
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return -EINPROGRESS;
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return rc;
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}
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static int net_dm_cmd_config(struct sk_buff *skb,
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struct genl_info *info)
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{
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return -ENOTSUPP;
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}
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static int net_dm_cmd_trace(struct sk_buff *skb,
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struct genl_info *info)
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{
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switch (info->genlhdr->cmd) {
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case NET_DM_CMD_START:
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return set_all_monitor_traces(TRACE_ON);
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break;
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case NET_DM_CMD_STOP:
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return set_all_monitor_traces(TRACE_OFF);
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break;
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}
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return -ENOTSUPP;
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}
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static int dropmon_net_event(struct notifier_block *ev_block,
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unsigned long event, void *ptr)
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{
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struct net_device *dev = ptr;
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struct dm_hw_stat_delta *new_stat = NULL;
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struct dm_hw_stat_delta *tmp;
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switch (event) {
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case NETDEV_REGISTER:
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new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
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if (!new_stat)
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goto out;
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new_stat->dev = dev;
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new_stat->last_rx = jiffies;
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INIT_RCU_HEAD(&new_stat->rcu);
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spin_lock(&trace_state_lock);
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list_add_rcu(&new_stat->list, &hw_stats_list);
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spin_unlock(&trace_state_lock);
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break;
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case NETDEV_UNREGISTER:
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spin_lock(&trace_state_lock);
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list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
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if (new_stat->dev == dev) {
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new_stat->dev = NULL;
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if (trace_state == TRACE_OFF) {
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list_del_rcu(&new_stat->list);
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call_rcu(&new_stat->rcu, free_dm_hw_stat);
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break;
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}
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}
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}
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spin_unlock(&trace_state_lock);
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break;
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}
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out:
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return NOTIFY_DONE;
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}
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static struct genl_ops dropmon_ops[] = {
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{
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.cmd = NET_DM_CMD_CONFIG,
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.doit = net_dm_cmd_config,
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},
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{
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.cmd = NET_DM_CMD_START,
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.doit = net_dm_cmd_trace,
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},
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{
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.cmd = NET_DM_CMD_STOP,
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.doit = net_dm_cmd_trace,
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},
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};
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static struct notifier_block dropmon_net_notifier = {
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.notifier_call = dropmon_net_event
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};
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static int __init init_net_drop_monitor(void)
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{
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int cpu;
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int rc, i, ret;
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struct per_cpu_dm_data *data;
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printk(KERN_INFO "Initalizing network drop monitor service\n");
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if (sizeof(void *) > 8) {
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printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n");
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return -ENOSPC;
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}
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if (genl_register_family(&net_drop_monitor_family) < 0) {
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printk(KERN_ERR "Could not create drop monitor netlink family\n");
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return -EFAULT;
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}
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rc = -EFAULT;
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for (i = 0; i < ARRAY_SIZE(dropmon_ops); i++) {
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ret = genl_register_ops(&net_drop_monitor_family,
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&dropmon_ops[i]);
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if (ret) {
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printk(KERN_CRIT "Failed to register operation %d\n",
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dropmon_ops[i].cmd);
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goto out_unreg;
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}
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}
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rc = register_netdevice_notifier(&dropmon_net_notifier);
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if (rc < 0) {
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printk(KERN_CRIT "Failed to register netdevice notifier\n");
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goto out_unreg;
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}
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rc = 0;
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for_each_present_cpu(cpu) {
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data = &per_cpu(dm_cpu_data, cpu);
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reset_per_cpu_data(data);
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INIT_WORK(&data->dm_alert_work, send_dm_alert);
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init_timer(&data->send_timer);
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data->send_timer.data = cpu;
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data->send_timer.function = sched_send_work;
|
||
|
|
}
|
||
|
|
|
||
|
|
goto out;
|
||
|
|
|
||
|
|
out_unreg:
|
||
|
|
genl_unregister_family(&net_drop_monitor_family);
|
||
|
|
out:
|
||
|
|
return rc;
|
||
|
|
}
|
||
|
|
|
||
|
|
late_initcall(init_net_drop_monitor);
|