diff options
| -rw-r--r-- | include/uapi/linux/net_dropmon.h | 27 | ||||
| -rw-r--r-- | net/core/drop_monitor.c | 280 |
2 files changed, 305 insertions, 2 deletions
diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h index 0fecdedeb6ca..cfaaf75371b8 100644 --- a/include/uapi/linux/net_dropmon.h +++ b/include/uapi/linux/net_dropmon.h @@ -53,6 +53,7 @@ enum { NET_DM_CMD_CONFIG, NET_DM_CMD_START, NET_DM_CMD_STOP, + NET_DM_CMD_PACKET_ALERT, _NET_DM_CMD_MAX, }; @@ -63,12 +64,38 @@ enum { */ #define NET_DM_GRP_ALERT 1 +enum net_dm_attr { + NET_DM_ATTR_UNSPEC, + + NET_DM_ATTR_ALERT_MODE, /* u8 */ + NET_DM_ATTR_PC, /* u64 */ + NET_DM_ATTR_SYMBOL, /* string */ + NET_DM_ATTR_IN_PORT, /* nested */ + NET_DM_ATTR_TIMESTAMP, /* struct timespec */ + NET_DM_ATTR_PROTO, /* u16 */ + NET_DM_ATTR_PAYLOAD, /* binary */ + NET_DM_ATTR_PAD, + + __NET_DM_ATTR_MAX, + NET_DM_ATTR_MAX = __NET_DM_ATTR_MAX - 1 +}; + /** * enum net_dm_alert_mode - Alert mode. * @NET_DM_ALERT_MODE_SUMMARY: A summary of recent drops is sent to user space. + * @NET_DM_ALERT_MODE_PACKET: Each dropped packet is sent to user space along + * with metadata. */ enum net_dm_alert_mode { NET_DM_ALERT_MODE_SUMMARY, + NET_DM_ALERT_MODE_PACKET, +}; + +enum { + NET_DM_ATTR_PORT_NETDEV_IFINDEX, /* u32 */ + + __NET_DM_ATTR_PORT_MAX, + NET_DM_ATTR_PORT_MAX = __NET_DM_ATTR_PORT_MAX - 1 }; #endif diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index 9cd2f662cb9e..ba765832413b 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -54,6 +54,7 @@ static DEFINE_MUTEX(net_dm_mutex); struct per_cpu_dm_data { spinlock_t lock; /* Protects 'skb' and 'send_timer' */ struct sk_buff *skb; + struct sk_buff_head drop_queue; struct work_struct dm_alert_work; struct timer_list send_timer; }; @@ -85,6 +86,14 @@ struct net_dm_alert_ops { void (*work_item_func)(struct work_struct *work); }; +struct net_dm_skb_cb { + void *pc; +}; + +#define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0])) + +#define NET_DM_QUEUE_LEN 1000 + static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data) { size_t al; @@ -257,8 +266,214 @@ static const struct net_dm_alert_ops net_dm_alert_summary_ops = { .work_item_func = send_dm_alert, }; +static void net_dm_packet_trace_kfree_skb_hit(void *ignore, + struct sk_buff *skb, + void *location) +{ + ktime_t tstamp = ktime_get_real(); + struct per_cpu_dm_data *data; + struct sk_buff *nskb; + unsigned long flags; + + nskb = skb_clone(skb, GFP_ATOMIC); + if (!nskb) + return; + + NET_DM_SKB_CB(nskb)->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); + 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)); +} + +#define NET_DM_MAX_SYMBOL_LEN 40 + +static size_t net_dm_packet_report_size(size_t payload_len) +{ + size_t size; + + size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); + + return NLMSG_ALIGN(size) + + /* 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(struct timespec)) + + /* NET_DM_ATTR_PROTO */ + nla_total_size(sizeof(u16)) + + /* NET_DM_ATTR_PAYLOAD */ + nla_total_size(payload_len); +} + +static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex) +{ + 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; + + 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) +{ + u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc; + char buf[NET_DM_MAX_SYMBOL_LEN]; + struct nlattr *attr; + struct timespec ts; + 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_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD)) + goto nla_put_failure; + + snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->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); + if (rc) + goto nla_put_failure; + + if (ktime_to_timespec_cond(skb->tstamp, &ts) && + nla_put(msg, NET_DM_ATTR_TIMESTAMP, sizeof(ts), &ts)) + 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); + + msg = nlmsg_new(net_dm_packet_report_size(payload_len), 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 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, +}; + 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, }; static int net_dm_trace_on_set(struct netlink_ext_ack *extack) @@ -326,9 +541,12 @@ static void net_dm_trace_off_set(void) */ 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); } list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) { @@ -370,12 +588,61 @@ static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) return rc; } +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: /* fall-through */ + 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 int net_dm_cmd_config(struct sk_buff *skb, struct genl_info *info) { - NL_SET_ERR_MSG_MOD(info->extack, "Command not supported"); + struct netlink_ext_ack *extack = info->extack; + int rc; - return -EOPNOTSUPP; + if (trace_state == TRACE_ON) { + NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor while tracing is on"); + return -EBUSY; + } + + rc = net_dm_alert_mode_set(info); + if (rc) + return rc; + + return 0; } static int net_dm_cmd_trace(struct sk_buff *skb, @@ -430,6 +697,11 @@ out: 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 }, +}; + static const struct genl_ops dropmon_ops[] = { { .cmd = NET_DM_CMD_CONFIG, @@ -467,6 +739,8 @@ 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, @@ -510,6 +784,7 @@ static int __init init_net_drop_monitor(void) for_each_possible_cpu(cpu) { data = &per_cpu(dm_cpu_data, cpu); spin_lock_init(&data->lock); + skb_queue_head_init(&data->drop_queue); } goto out; @@ -539,6 +814,7 @@ static void exit_net_drop_monitor(void) * to this struct and can free the skb inside it */ kfree_skb(data->skb); + WARN_ON(!skb_queue_empty(&data->drop_queue)); } BUG_ON(genl_unregister_family(&net_drop_monitor_family)); |