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Network Drop Monitor: Adding drop monitor implementation & Netlink protocol
Signed-off-by: Neil Horman <nhorman@tuxdriver.com> include/linux/net_dropmon.h | 56 +++++++++ net/core/drop_monitor.c | 263 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 319 insertions(+) Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Neil Horman
David S. Miller
parent
ead2ceb0ec
commit
9a8afc8d39
56
include/linux/net_dropmon.h
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56
include/linux/net_dropmon.h
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@ -0,0 +1,56 @@
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#ifndef __NET_DROPMON_H
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#define __NET_DROPMON_H
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#include <linux/netlink.h>
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struct net_dm_drop_point {
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__u8 pc[8];
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__u32 count;
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};
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#define NET_DM_CFG_VERSION 0
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#define NET_DM_CFG_ALERT_COUNT 1
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#define NET_DM_CFG_ALERT_DELAY 2
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#define NET_DM_CFG_MAX 3
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struct net_dm_config_entry {
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__u32 type;
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__u64 data __attribute__((aligned(8)));
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};
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struct net_dm_config_msg {
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__u32 entries;
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struct net_dm_config_entry options[0];
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};
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struct net_dm_alert_msg {
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__u32 entries;
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struct net_dm_drop_point points[0];
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};
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struct net_dm_user_msg {
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union {
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struct net_dm_config_msg user;
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struct net_dm_alert_msg alert;
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} u;
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};
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/* These are the netlink message types for this protocol */
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enum {
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NET_DM_CMD_UNSPEC = 0,
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NET_DM_CMD_ALERT,
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NET_DM_CMD_CONFIG,
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NET_DM_CMD_START,
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NET_DM_CMD_STOP,
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_NET_DM_CMD_MAX,
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};
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#define NET_DM_CMD_MAX (_NET_DM_CMD_MAX - 1)
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/*
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* Our group identifiers
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*/
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#define NET_DM_GRP_ALERT 1
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#endif
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263
net/core/drop_monitor.c
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263
net/core/drop_monitor.c
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@ -0,0 +1,263 @@
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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 <trace/skb.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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struct sock *dm_sock;
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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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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 = 1,
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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 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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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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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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msg = __nla_reserve_nohdr(data->skb, sizeof(struct net_dm_alert_msg));
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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_kfree_skb_hit(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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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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msg = genlmsg_data(nlmsg_data(nlh));
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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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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 int set_all_monitor_traces(int state)
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{
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int rc = 0;
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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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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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tracepoint_synchronize_unregister();
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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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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 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 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 = 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;
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}
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goto out;
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out_unreg:
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genl_unregister_family(&net_drop_monitor_family);
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out:
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return rc;
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}
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late_initcall(init_net_drop_monitor);
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