diff options
| -rw-r--r-- | include/linux/net_dropmon.h | 56 | ||||
| -rw-r--r-- | net/core/drop_monitor.c | 263 |
2 files changed, 319 insertions, 0 deletions
diff --git a/include/linux/net_dropmon.h b/include/linux/net_dropmon.h new file mode 100644 index 00000000000..0217fb81a63 --- /dev/null +++ b/include/linux/net_dropmon.h @@ -0,0 +1,56 @@ +#ifndef __NET_DROPMON_H +#define __NET_DROPMON_H + +#include <linux/netlink.h> + +struct net_dm_drop_point { + __u8 pc[8]; + __u32 count; +}; + +#define NET_DM_CFG_VERSION 0 +#define NET_DM_CFG_ALERT_COUNT 1 +#define NET_DM_CFG_ALERT_DELAY 2 +#define NET_DM_CFG_MAX 3 + +struct net_dm_config_entry { + __u32 type; + __u64 data __attribute__((aligned(8))); +}; + +struct net_dm_config_msg { + __u32 entries; + struct net_dm_config_entry options[0]; +}; + +struct net_dm_alert_msg { + __u32 entries; + struct net_dm_drop_point points[0]; +}; + +struct net_dm_user_msg { + union { + struct net_dm_config_msg user; + struct net_dm_alert_msg alert; + } u; +}; + + +/* These are the netlink message types for this protocol */ + +enum { + NET_DM_CMD_UNSPEC = 0, + NET_DM_CMD_ALERT, + NET_DM_CMD_CONFIG, + NET_DM_CMD_START, + NET_DM_CMD_STOP, + _NET_DM_CMD_MAX, +}; + +#define NET_DM_CMD_MAX (_NET_DM_CMD_MAX - 1) + +/* + * Our group identifiers + */ +#define NET_DM_GRP_ALERT 1 +#endif diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c new file mode 100644 index 00000000000..9fd0dc3cca9 --- /dev/null +++ b/net/core/drop_monitor.c @@ -0,0 +1,263 @@ +/* + * Monitoring code for network dropped packet alerts + * + * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com> + */ + +#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 <net/genetlink.h> + +#include <trace/skb.h> + +#include <asm/unaligned.h> + +#define TRACE_ON 1 +#define TRACE_OFF 0 + +static void send_dm_alert(struct work_struct *unused); + + +/* + * Globals, our netlink socket pointer + * and the work handle that will send up + * netlink alerts + */ +struct sock *dm_sock; + +struct per_cpu_dm_data { + struct work_struct dm_alert_work; + struct sk_buff *skb; + atomic_t dm_hit_count; + struct timer_list send_timer; +}; + +static struct genl_family net_drop_monitor_family = { + .id = GENL_ID_GENERATE, + .hdrsize = 0, + .name = "NET_DM", + .version = 1, + .maxattr = NET_DM_CMD_MAX, +}; + +static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data); + +static int dm_hit_limit = 64; +static int dm_delay = 1; + + +static void reset_per_cpu_data(struct per_cpu_dm_data *data) +{ + size_t al; + struct net_dm_alert_msg *msg; + + al = sizeof(struct net_dm_alert_msg); + al += dm_hit_limit * sizeof(struct net_dm_drop_point); + data->skb = genlmsg_new(al, GFP_KERNEL); + genlmsg_put(data->skb, 0, 0, &net_drop_monitor_family, + 0, NET_DM_CMD_ALERT); + msg = __nla_reserve_nohdr(data->skb, sizeof(struct net_dm_alert_msg)); + memset(msg, 0, al); + atomic_set(&data->dm_hit_count, dm_hit_limit); +} + +static void send_dm_alert(struct work_struct *unused) +{ + struct sk_buff *skb; + struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data); + + /* + * Grab the skb we're about to send + */ + skb = data->skb; + + /* + * Replace it with a new one + */ + reset_per_cpu_data(data); + + /* + * Ship it! + */ + genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, 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. Note that it operates under the timer interrupt + * so we don't need to disable preemption here + */ +static void sched_send_work(unsigned long unused) +{ + struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data); + + schedule_work(&data->dm_alert_work); +} + +static void trace_kfree_skb_hit(struct sk_buff *skb, void *location) +{ + struct net_dm_alert_msg *msg; + struct nlmsghdr *nlh; + int i; + struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data); + + + if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) { + /* + * we're already at zero, discard this hit + */ + goto out; + } + + nlh = (struct nlmsghdr *)data->skb->data; + msg = genlmsg_data(nlmsg_data(nlh)); + for (i = 0; i < msg->entries; i++) { + if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) { + msg->points[i].count++; + goto out; + } + } + + /* + * We need to create a new entry + */ + __nla_reserve_nohdr(data->skb, 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_on(&data->send_timer, smp_processor_id()); + } + +out: + return; +} + +static int set_all_monitor_traces(int state) +{ + int rc = 0; + + switch (state) { + case TRACE_ON: + rc |= register_trace_kfree_skb(trace_kfree_skb_hit); + break; + case TRACE_OFF: + rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit); + + tracepoint_synchronize_unregister(); + break; + default: + rc = 1; + break; + } + + if (rc) + return -EINPROGRESS; + return rc; +} + + +static int net_dm_cmd_config(struct sk_buff *skb, + struct genl_info *info) +{ + return -ENOTSUPP; +} + +static int net_dm_cmd_trace(struct sk_buff *skb, + struct genl_info *info) +{ + switch (info->genlhdr->cmd) { + case NET_DM_CMD_START: + return set_all_monitor_traces(TRACE_ON); + break; + case NET_DM_CMD_STOP: + return set_all_monitor_traces(TRACE_OFF); + break; + } + + return -ENOTSUPP; +} + + +static struct genl_ops dropmon_ops[] = { + { + .cmd = NET_DM_CMD_CONFIG, + .doit = net_dm_cmd_config, + }, + { + .cmd = NET_DM_CMD_START, + .doit = net_dm_cmd_trace, + }, + { + .cmd = NET_DM_CMD_STOP, + .doit = net_dm_cmd_trace, + }, +}; + +static int __init init_net_drop_monitor(void) +{ + int cpu; + int rc, i, ret; + struct per_cpu_dm_data *data; + printk(KERN_INFO "Initalizing network drop monitor service\n"); + + if (sizeof(void *) > 8) { + printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n"); + return -ENOSPC; + } + + if (genl_register_family(&net_drop_monitor_family) < 0) { + printk(KERN_ERR "Could not create drop monitor netlink family\n"); + return -EFAULT; + } + + rc = -EFAULT; + + for (i = 0; i < ARRAY_SIZE(dropmon_ops); i++) { + ret = genl_register_ops(&net_drop_monitor_family, + &dropmon_ops[i]); + if (ret) { + printk(KERN_CRIT "failed to register operation %d\n", + dropmon_ops[i].cmd); + goto out_unreg; + } + } + + rc = 0; + + for_each_present_cpu(cpu) { + data = &per_cpu(dm_cpu_data, cpu); + reset_per_cpu_data(data); + INIT_WORK(&data->dm_alert_work, send_dm_alert); + init_timer(&data->send_timer); + data->send_timer.data = cpu; + 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); |