From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:02:30 +0200 Subject: Adding upstream version 4.19.249. Signed-off-by: Daniel Baumann --- net/core/drop_monitor.c | 472 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 472 insertions(+) create mode 100644 net/core/drop_monitor.c (limited to 'net/core/drop_monitor.c') diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c new file mode 100644 index 000000000..2ed600012 --- /dev/null +++ b/net/core/drop_monitor.c @@ -0,0 +1,472 @@ +/* + * Monitoring code for network dropped packet alerts + * + * Copyright (C) 2009 Neil Horman + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include + +#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 DEFINE_MUTEX(trace_state_mutex); + +struct per_cpu_dm_data { + spinlock_t lock; + struct sk_buff *skb; + struct work_struct dm_alert_work; + struct timer_list send_timer; +}; + +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 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 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 net_dm_drop_point *point; + 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); + point = msg->points; + for (i = 0; i < msg->entries; i++) { + if (!memcmp(&location, &point->pc, sizeof(void *))) { + point->count++; + goto out; + } + point++; + } + 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(point->pc, &location, sizeof(void *)); + point->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) { + struct net_device *dev; + + /* + * 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 + */ + /* Paired with WRITE_ONCE() in dropmon_net_event() */ + dev = READ_ONCE(new_stat->dev); + if ((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 int set_all_monitor_traces(int state) +{ + int rc = 0; + struct dm_hw_stat_delta *new_stat = NULL; + struct dm_hw_stat_delta *temp; + + mutex_lock(&trace_state_mutex); + + if (state == trace_state) { + rc = -EAGAIN; + goto out_unlock; + } + + switch (state) { + case TRACE_ON: + if (!try_module_get(THIS_MODULE)) { + rc = -ENODEV; + break; + } + + rc |= register_trace_kfree_skb(trace_kfree_skb_hit, NULL); + rc |= register_trace_napi_poll(trace_napi_poll_hit, NULL); + break; + + case TRACE_OFF: + rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit, NULL); + rc |= unregister_trace_napi_poll(trace_napi_poll_hit, NULL); + + tracepoint_synchronize_unregister(); + + /* + * Clean the device list + */ + list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) { + if (new_stat->dev == NULL) { + list_del_rcu(&new_stat->list); + kfree_rcu(new_stat, rcu); + } + } + + module_put(THIS_MODULE); + + break; + default: + rc = 1; + break; + } + + if (!rc) + trace_state = state; + else + rc = -EINPROGRESS; + +out_unlock: + mutex_unlock(&trace_state_mutex); + + 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); + case NET_DM_CMD_STOP: + return set_all_monitor_traces(TRACE_OFF); + } + + return -ENOTSUPP; +} + +static int dropmon_net_event(struct notifier_block *ev_block, + unsigned long event, void *ptr) +{ + struct net_device *dev = netdev_notifier_info_to_dev(ptr); + struct dm_hw_stat_delta *new_stat = NULL; + struct dm_hw_stat_delta *tmp; + + switch (event) { + case NETDEV_REGISTER: + new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL); + + if (!new_stat) + goto out; + + new_stat->dev = dev; + new_stat->last_rx = jiffies; + mutex_lock(&trace_state_mutex); + list_add_rcu(&new_stat->list, &hw_stats_list); + mutex_unlock(&trace_state_mutex); + break; + case NETDEV_UNREGISTER: + mutex_lock(&trace_state_mutex); + list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) { + if (new_stat->dev == dev) { + + /* Paired with READ_ONCE() in trace_napi_poll_hit() */ + WRITE_ONCE(new_stat->dev, NULL); + + if (trace_state == TRACE_OFF) { + list_del_rcu(&new_stat->list); + kfree_rcu(new_stat, rcu); + break; + } + } + } + mutex_unlock(&trace_state_mutex); + break; + } +out: + return NOTIFY_DONE; +} + +static const 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 struct genl_family net_drop_monitor_family __ro_after_init = { + .hdrsize = 0, + .name = "NET_DM", + .version = 2, + .module = THIS_MODULE, + .ops = dropmon_ops, + .n_ops = ARRAY_SIZE(dropmon_ops), + .mcgrps = dropmon_mcgrps, + .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), +}; + +static struct notifier_block dropmon_net_notifier = { + .notifier_call = dropmon_net_event +}; + +static int __init init_net_drop_monitor(void) +{ + struct per_cpu_dm_data *data; + int cpu, rc; + + pr_info("Initializing network drop monitor service\n"); + + if (sizeof(void *) > 8) { + pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); + return -ENOSPC; + } + + rc = genl_register_family(&net_drop_monitor_family); + if (rc) { + pr_err("Could not create drop monitor netlink family\n"); + return rc; + } + WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); + + rc = register_netdevice_notifier(&dropmon_net_notifier); + if (rc < 0) { + pr_crit("Failed to register netdevice notifier\n"); + goto out_unreg; + } + + rc = 0; + + for_each_possible_cpu(cpu) { + data = &per_cpu(dm_cpu_data, cpu); + INIT_WORK(&data->dm_alert_work, send_dm_alert); + timer_setup(&data->send_timer, sched_send_work, 0); + spin_lock_init(&data->lock); + reset_per_cpu_data(data); + } + + + goto out; + +out_unreg: + genl_unregister_family(&net_drop_monitor_family); +out: + return rc; +} + +static void exit_net_drop_monitor(void) +{ + struct per_cpu_dm_data *data; + int cpu; + + BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); + + /* + * Because of the module_get/put we do in the trace state change path + * we are guarnateed not to have any current users when we get here + * all we need to do is make sure that we don't have any running timers + * or pending schedule calls + */ + + for_each_possible_cpu(cpu) { + data = &per_cpu(dm_cpu_data, cpu); + del_timer_sync(&data->send_timer); + cancel_work_sync(&data->dm_alert_work); + /* + * At this point, we should have exclusive access + * to this struct and can free the skb inside it + */ + kfree_skb(data->skb); + } + + BUG_ON(genl_unregister_family(&net_drop_monitor_family)); +} + +module_init(init_net_drop_monitor); +module_exit(exit_net_drop_monitor); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Neil Horman "); +MODULE_ALIAS_GENL_FAMILY("NET_DM"); -- cgit v1.2.3