diff options
Diffstat (limited to 'net/core/drop_monitor.c')
| -rw-r--r-- | net/core/drop_monitor.c | 1772 |
1 files changed, 1772 insertions, 0 deletions
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c new file mode 100644 index 000000000..8e0a90b45 --- /dev/null +++ b/net/core/drop_monitor.c @@ -0,0 +1,1772 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Monitoring code for network dropped packet alerts + * + * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com> + */ + +#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/genetlink.h> +#include <net/netevent.h> +#include <net/flow_offload.h> +#include <net/devlink.h> + +#include <trace/events/skb.h> +#include <trace/events/napi.h> +#include <trace/events/devlink.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. + */ +static DEFINE_MUTEX(net_dm_mutex); + +struct net_dm_stats { + u64_stats_t 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[]; +}; + +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 { + unsigned long last_rx; + unsigned long last_drop_val; + struct rcu_head rcu; +}; + +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 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, + enum skb_drop_reason reason); + 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_trap_probe)(void *ignore, const struct devlink *devlink, + struct sk_buff *skb, + const struct devlink_trap_metadata *metadata); +}; + +struct net_dm_skb_cb { + union { + struct devlink_trap_metadata *hw_metadata; + void *pc; + }; + enum skb_drop_reason reason; +}; + +#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", .cap_sys_admin = 1 }, +}; + +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, + enum skb_drop_reason reason) +{ + trace_drop_common(skb, location); +} + +static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi, + int work, int budget) +{ + struct net_device *dev = napi->dev; + struct dm_hw_stat_delta *stat; + /* + * Don't check napi structures with no associated device + */ + if (!dev) + return; + + rcu_read_lock(); + stat = rcu_dereference(dev->dm_private); + if (stat) { + /* + * only add a note to our monitor buffer if: + * 1) its after the last_rx delta + * 2) our rx_dropped count has gone up + */ + if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) && + (dev->stats.rx_dropped != stat->last_drop_val)) { + trace_drop_common(NULL, NULL); + stat->last_drop_val = dev->stats.rx_dropped; + stat->last_rx = jiffies; + } + } + 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_trap_summary_probe(void *ignore, const struct devlink *devlink, + struct sk_buff *skb, + const struct devlink_trap_metadata *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; + + if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) + return; + + 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, 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]; + strscpy(hw_entry->trap_name, 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_trap_probe = net_dm_hw_trap_summary_probe, +}; + +static void net_dm_packet_trace_kfree_skb_hit(void *ignore, + struct sk_buff *skb, + void *location, + enum skb_drop_reason reason) +{ + ktime_t tstamp = ktime_get_real(); + struct per_cpu_dm_data *data; + struct net_dm_skb_cb *cb; + struct sk_buff *nskb; + unsigned long flags; + + if (!skb_mac_header_was_set(skb)) + return; + + nskb = skb_clone(skb, GFP_ATOMIC); + if (!nskb) + return; + + if (unlikely(reason >= SKB_DROP_REASON_MAX || reason <= 0)) + reason = SKB_DROP_REASON_NOT_SPECIFIED; + cb = NET_DM_SKB_CB(nskb); + cb->reason = reason; + cb->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); + u64_stats_inc(&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, + enum skb_drop_reason reason) +{ + 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_REASON */ + nla_total_size(strlen(drop_reasons[reason]) + 1) + + /* 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) +{ + struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb); + 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, (u64)(uintptr_t)cb->pc, + NET_DM_ATTR_PAD)) + goto nla_put_failure; + + if (nla_put_string(msg, NET_DM_ATTR_REASON, + drop_reasons[cb->reason])) + goto nla_put_failure; + + snprintf(buf, sizeof(buf), "%pS", cb->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, + NET_DM_SKB_CB(skb)->reason), + 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_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata) +{ + return hw_metadata->fa_cookie ? + nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0; +} + +static size_t +net_dm_hw_packet_report_size(size_t payload_len, + const struct devlink_trap_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_FLOW_ACTION_COOKIE */ + net_dm_flow_action_cookie_size(hw_metadata) + + /* 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 devlink_trap_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 (hw_metadata->fa_cookie && + nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE, + hw_metadata->fa_cookie->cookie_len, + hw_metadata->fa_cookie->cookie)) + 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 devlink_trap_metadata * +net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata) +{ + const struct flow_action_cookie *fa_cookie; + struct devlink_trap_metadata *hw_metadata; + const char *trap_group_name; + const char *trap_name; + + hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC); + if (!hw_metadata) + return NULL; + + trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC); + if (!trap_group_name) + goto free_hw_metadata; + hw_metadata->trap_group_name = trap_group_name; + + trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC); + if (!trap_name) + goto free_trap_group; + hw_metadata->trap_name = trap_name; + + if (metadata->fa_cookie) { + size_t cookie_size = sizeof(*fa_cookie) + + metadata->fa_cookie->cookie_len; + + fa_cookie = kmemdup(metadata->fa_cookie, cookie_size, + GFP_ATOMIC); + if (!fa_cookie) + goto free_trap_name; + hw_metadata->fa_cookie = fa_cookie; + } + + hw_metadata->input_dev = metadata->input_dev; + netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker, + GFP_ATOMIC); + + return hw_metadata; + +free_trap_name: + kfree(trap_name); +free_trap_group: + kfree(trap_group_name); +free_hw_metadata: + kfree(hw_metadata); + return NULL; +} + +static void +net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata) +{ + netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker); + kfree(hw_metadata->fa_cookie); + 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 devlink_trap_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_trap_packet_probe(void *ignore, const struct devlink *devlink, + struct sk_buff *skb, + const struct devlink_trap_metadata *metadata) +{ + struct devlink_trap_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 (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) + return; + + if (!skb_mac_header_was_set(skb)) + return; + + nskb = skb_clone(skb, GFP_ATOMIC); + if (!nskb) + return; + + n_hw_metadata = net_dm_hw_metadata_copy(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); + u64_stats_inc(&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_trap_probe = net_dm_hw_trap_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, +}; + +#if IS_ENABLED(CONFIG_NET_DEVLINK) +static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) +{ + return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL); +} + +static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) +{ + unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL); + tracepoint_synchronize_unregister(); +} +#else +static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) +{ + return -EOPNOTSUPP; +} + +static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) +{ +} +#endif + +static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack) +{ + const struct net_dm_alert_ops *ops; + int cpu, rc; + + 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); + } + + rc = net_dm_hw_probe_register(ops); + if (rc) { + NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint"); + goto err_module_put; + } + + monitor_hw = true; + + return 0; + +err_module_put: + for_each_possible_cpu(cpu) { + struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); + struct sk_buff *skb; + + del_timer_sync(&hw_data->send_timer); + cancel_work_sync(&hw_data->dm_alert_work); + while ((skb = __skb_dequeue(&hw_data->drop_queue))) { + struct devlink_trap_metadata *hw_metadata; + + hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; + net_dm_hw_metadata_free(hw_metadata); + consume_skb(skb); + } + } + module_put(THIS_MODULE); + return rc; +} + +static void net_dm_hw_monitor_stop(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 disabled"); + return; + } + + ops = net_dm_alert_ops_arr[net_dm_alert_mode]; + + monitor_hw = false; + + net_dm_hw_probe_unregister(ops); + + for_each_possible_cpu(cpu) { + struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); + struct sk_buff *skb; + + del_timer_sync(&hw_data->send_timer); + cancel_work_sync(&hw_data->dm_alert_work); + while ((skb = __skb_dequeue(&hw_data->drop_queue))) { + struct devlink_trap_metadata *hw_metadata; + + hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; + net_dm_hw_metadata_free(hw_metadata); + consume_skb(skb); + } + } + + module_put(THIS_MODULE); +} + +static int net_dm_trace_on_set(struct netlink_ext_ack *extack) +{ + const struct net_dm_alert_ops *ops; + int cpu, rc; + + 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 *data = &per_cpu(dm_cpu_data, cpu); + struct sk_buff *skb; + + INIT_WORK(&data->dm_alert_work, ops->work_item_func); + timer_setup(&data->send_timer, sched_send_work, 0); + /* Allocate a new per-CPU skb for the summary alert message and + * free the old one which might contain stale data from + * previous tracing. + */ + skb = reset_per_cpu_data(data); + consume_skb(skb); + } + + rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL); + if (rc) { + NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint"); + goto err_module_put; + } + + rc = register_trace_napi_poll(ops->napi_poll_probe, NULL); + if (rc) { + NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint"); + goto err_unregister_trace; + } + + return 0; + +err_unregister_trace: + unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); +err_module_put: + for_each_possible_cpu(cpu) { + struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); + struct sk_buff *skb; + + del_timer_sync(&data->send_timer); + cancel_work_sync(&data->dm_alert_work); + while ((skb = __skb_dequeue(&data->drop_queue))) + consume_skb(skb); + } + module_put(THIS_MODULE); + return rc; +} + +static void net_dm_trace_off_set(void) +{ + const struct net_dm_alert_ops *ops; + int cpu; + + ops = net_dm_alert_ops_arr[net_dm_alert_mode]; + + unregister_trace_napi_poll(ops->napi_poll_probe, NULL); + unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); + + tracepoint_synchronize_unregister(); + + /* Make sure we do not send notifications to user space after request + * to stop tracing returns. + */ + for_each_possible_cpu(cpu) { + struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); + struct sk_buff *skb; + + del_timer_sync(&data->send_timer); + cancel_work_sync(&data->dm_alert_work); + while ((skb = __skb_dequeue(&data->drop_queue))) + consume_skb(skb); + } + + module_put(THIS_MODULE); +} + +static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) +{ + int rc = 0; + + if (state == trace_state) { + NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state"); + return -EAGAIN; + } + + switch (state) { + case TRACE_ON: + rc = net_dm_trace_on_set(extack); + break; + case TRACE_OFF: + net_dm_trace_off_set(); + break; + default: + rc = 1; + break; + } + + if (!rc) + trace_state = state; + else + rc = -EINPROGRESS; + + return rc; +} + +static bool net_dm_is_monitoring(void) +{ + return trace_state == TRACE_ON || monitor_hw; +} + +static int net_dm_alert_mode_get_from_info(struct genl_info *info, + enum net_dm_alert_mode *p_alert_mode) +{ + u8 val; + + val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]); + + switch (val) { + case NET_DM_ALERT_MODE_SUMMARY: + case NET_DM_ALERT_MODE_PACKET: + *p_alert_mode = val; + break; + default: + return -EINVAL; + } + + return 0; +} + +static int net_dm_alert_mode_set(struct genl_info *info) +{ + struct netlink_ext_ack *extack = info->extack; + enum net_dm_alert_mode alert_mode; + int rc; + + if (!info->attrs[NET_DM_ATTR_ALERT_MODE]) + return 0; + + rc = net_dm_alert_mode_get_from_info(info, &alert_mode); + if (rc) { + NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode"); + return -EINVAL; + } + + net_dm_alert_mode = alert_mode; + + return 0; +} + +static void net_dm_trunc_len_set(struct genl_info *info) +{ + if (!info->attrs[NET_DM_ATTR_TRUNC_LEN]) + return; + + net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]); +} + +static void net_dm_queue_len_set(struct genl_info *info) +{ + if (!info->attrs[NET_DM_ATTR_QUEUE_LEN]) + return; + + net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]); +} + +static int net_dm_cmd_config(struct sk_buff *skb, + struct genl_info *info) +{ + struct netlink_ext_ack *extack = info->extack; + int rc; + + if (net_dm_is_monitoring()) { + NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring"); + return -EBUSY; + } + + rc = net_dm_alert_mode_set(info); + if (rc) + return rc; + + net_dm_trunc_len_set(info); + + net_dm_queue_len_set(info); + + return 0; +} + +static int net_dm_monitor_start(bool set_sw, bool set_hw, + struct netlink_ext_ack *extack) +{ + bool sw_set = false; + int rc; + + if (set_sw) { + rc = set_all_monitor_traces(TRACE_ON, extack); + if (rc) + return rc; + sw_set = true; + } + + if (set_hw) { + rc = net_dm_hw_monitor_start(extack); + if (rc) + goto err_monitor_hw; + } + + return 0; + +err_monitor_hw: + if (sw_set) + set_all_monitor_traces(TRACE_OFF, extack); + return rc; +} + +static void net_dm_monitor_stop(bool set_sw, bool set_hw, + struct netlink_ext_ack *extack) +{ + if (set_hw) + net_dm_hw_monitor_stop(extack); + if (set_sw) + set_all_monitor_traces(TRACE_OFF, extack); +} + +static int net_dm_cmd_trace(struct sk_buff *skb, + struct genl_info *info) +{ + bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS]; + bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS]; + struct netlink_ext_ack *extack = info->extack; + + /* To maintain backward compatibility, we start / stop monitoring of + * software drops if no flag is specified. + */ + if (!set_sw && !set_hw) + set_sw = true; + + switch (info->genlhdr->cmd) { + case NET_DM_CMD_START: + return net_dm_monitor_start(set_sw, set_hw, extack); + case NET_DM_CMD_STOP: + net_dm_monitor_stop(set_sw, set_hw, extack); + return 0; + } + + return -EOPNOTSUPP; +} + +static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info) +{ + void *hdr; + + hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, + &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW); + if (!hdr) + return -EMSGSIZE; + + if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode)) + goto nla_put_failure; + + if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len)) + goto nla_put_failure; + + if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len)) + goto nla_put_failure; + + genlmsg_end(msg, hdr); + + return 0; + +nla_put_failure: + genlmsg_cancel(msg, hdr); + return -EMSGSIZE; +} + +static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) +{ + struct sk_buff *msg; + int rc; + + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (!msg) + return -ENOMEM; + + rc = net_dm_config_fill(msg, info); + if (rc) + goto free_msg; + + return genlmsg_reply(msg, info); + +free_msg: + nlmsg_free(msg); + return rc; +} + +static void net_dm_stats_read(struct net_dm_stats *stats) +{ + int cpu; + + memset(stats, 0, sizeof(*stats)); + for_each_possible_cpu(cpu) { + struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); + struct net_dm_stats *cpu_stats = &data->stats; + unsigned int start; + u64 dropped; + + do { + start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); + dropped = u64_stats_read(&cpu_stats->dropped); + } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); + + u64_stats_add(&stats->dropped, dropped); + } +} + +static int net_dm_stats_put(struct sk_buff *msg) +{ + struct net_dm_stats stats; + struct nlattr *attr; + + net_dm_stats_read(&stats); + + attr = nla_nest_start(msg, NET_DM_ATTR_STATS); + if (!attr) + return -EMSGSIZE; + + if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, + u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) + goto nla_put_failure; + + nla_nest_end(msg, attr); + + return 0; + +nla_put_failure: + nla_nest_cancel(msg, attr); + return -EMSGSIZE; +} + +static void net_dm_hw_stats_read(struct net_dm_stats *stats) +{ + int cpu; + + memset(stats, 0, sizeof(*stats)); + for_each_possible_cpu(cpu) { + struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); + struct net_dm_stats *cpu_stats = &hw_data->stats; + unsigned int start; + u64 dropped; + + do { + start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); + dropped = u64_stats_read(&cpu_stats->dropped); + } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); + + u64_stats_add(&stats->dropped, dropped); + } +} + +static int net_dm_hw_stats_put(struct sk_buff *msg) +{ + struct net_dm_stats stats; + struct nlattr *attr; + + net_dm_hw_stats_read(&stats); + + attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS); + if (!attr) + return -EMSGSIZE; + + if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, + u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) + 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_stats_fill(struct sk_buff *msg, struct genl_info *info) +{ + void *hdr; + int rc; + + hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, + &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW); + if (!hdr) + return -EMSGSIZE; + + rc = net_dm_stats_put(msg); + if (rc) + goto nla_put_failure; + + rc = net_dm_hw_stats_put(msg); + if (rc) + goto nla_put_failure; + + genlmsg_end(msg, hdr); + + return 0; + +nla_put_failure: + genlmsg_cancel(msg, hdr); + return -EMSGSIZE; +} + +static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info) +{ + struct sk_buff *msg; + int rc; + + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (!msg) + return -ENOMEM; + + rc = net_dm_stats_fill(msg, info); + if (rc) + goto free_msg; + + return genlmsg_reply(msg, info); + +free_msg: + nlmsg_free(msg); + return rc; +} + +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 *stat; + + switch (event) { + case NETDEV_REGISTER: + if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private))) + break; + stat = kzalloc(sizeof(*stat), GFP_KERNEL); + if (!stat) + break; + + stat->last_rx = jiffies; + rcu_assign_pointer(dev->dm_private, stat); + + break; + case NETDEV_UNREGISTER: + stat = rtnl_dereference(dev->dm_private); + if (stat) { + rcu_assign_pointer(dev->dm_private, NULL); + kfree_rcu(stat, rcu); + } + break; + } + return NOTIFY_DONE; +} + +static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = { + [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 }, + [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 }, + [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 }, + [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 }, + [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG }, + [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG }, +}; + +static const struct genl_small_ops dropmon_ops[] = { + { + .cmd = NET_DM_CMD_CONFIG, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .doit = net_dm_cmd_config, + .flags = GENL_ADMIN_PERM, + }, + { + .cmd = NET_DM_CMD_START, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .doit = net_dm_cmd_trace, + .flags = GENL_ADMIN_PERM, + }, + { + .cmd = NET_DM_CMD_STOP, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .doit = net_dm_cmd_trace, + .flags = GENL_ADMIN_PERM, + }, + { + .cmd = NET_DM_CMD_CONFIG_GET, + .doit = net_dm_cmd_config_get, + }, + { + .cmd = NET_DM_CMD_STATS_GET, + .doit = net_dm_cmd_stats_get, + }, +}; + +static int net_dm_nl_pre_doit(const struct genl_ops *ops, + struct sk_buff *skb, struct genl_info *info) +{ + mutex_lock(&net_dm_mutex); + + return 0; +} + +static void net_dm_nl_post_doit(const struct genl_ops *ops, + struct sk_buff *skb, struct genl_info *info) +{ + mutex_unlock(&net_dm_mutex); +} + +static struct genl_family net_drop_monitor_family __ro_after_init = { + .hdrsize = 0, + .name = "NET_DM", + .version = 2, + .maxattr = NET_DM_ATTR_MAX, + .policy = net_dm_nl_policy, + .pre_doit = net_dm_nl_pre_doit, + .post_doit = net_dm_nl_post_doit, + .module = THIS_MODULE, + .small_ops = dropmon_ops, + .n_small_ops = ARRAY_SIZE(dropmon_ops), + .resv_start_op = NET_DM_CMD_STATS_GET + 1, + .mcgrps = dropmon_mcgrps, + .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), +}; + +static struct notifier_block dropmon_net_notifier = { + .notifier_call = dropmon_net_event +}; + +static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data) +{ + spin_lock_init(&data->lock); + skb_queue_head_init(&data->drop_queue); + u64_stats_init(&data->stats.syncp); +} + +static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data) +{ + WARN_ON(!skb_queue_empty(&data->drop_queue)); +} + +static void net_dm_cpu_data_init(int cpu) +{ + struct per_cpu_dm_data *data; + + data = &per_cpu(dm_cpu_data, cpu); + __net_dm_cpu_data_init(data); +} + +static void net_dm_cpu_data_fini(int cpu) +{ + struct per_cpu_dm_data *data; + + data = &per_cpu(dm_cpu_data, cpu); + /* At this point, we should have exclusive access + * to this struct and can free the skb inside it. + */ + consume_skb(data->skb); + __net_dm_cpu_data_fini(data); +} + +static void net_dm_hw_cpu_data_init(int cpu) +{ + struct per_cpu_dm_data *hw_data; + + hw_data = &per_cpu(dm_hw_cpu_data, cpu); + __net_dm_cpu_data_init(hw_data); +} + +static void net_dm_hw_cpu_data_fini(int cpu) +{ + struct per_cpu_dm_data *hw_data; + + hw_data = &per_cpu(dm_hw_cpu_data, cpu); + kfree(hw_data->hw_entries); + __net_dm_cpu_data_fini(hw_data); +} + +static int __init init_net_drop_monitor(void) +{ + 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) { + net_dm_cpu_data_init(cpu); + net_dm_hw_cpu_data_init(cpu); + } + + goto out; + +out_unreg: + genl_unregister_family(&net_drop_monitor_family); +out: + return rc; +} + +static void exit_net_drop_monitor(void) +{ + 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 guaranteed not to have any current users when we get here + */ + + for_each_possible_cpu(cpu) { + net_dm_hw_cpu_data_fini(cpu); + net_dm_cpu_data_fini(cpu); + } + + 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 <nhorman@tuxdriver.com>"); +MODULE_ALIAS_GENL_FAMILY("NET_DM"); +MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts"); |