# Suricata Input Plugin This plugin reports internal performance counters of the Suricata IDS/IPS engine, such as captured traffic volume, memory usage, uptime, flow counters, and much more. It provides a socket for the Suricata log output to write JSON stats output to, and processes the incoming data to fit Telegraf's format. It can also report for triggered Suricata IDS/IPS alerts. ## Service Input This plugin is a service input. Normal plugins gather metrics determined by the interval setting. Service plugins start a service to listen and wait for metrics or events to occur. Service plugins have two key differences from normal plugins: 1. The global or plugin specific `interval` setting may not apply 2. The CLI options of `--test`, `--test-wait`, and `--once` may not produce output for this plugin ## Global configuration options In addition to the plugin-specific configuration settings, plugins support additional global and plugin configuration settings. These settings are used to modify metrics, tags, and field or create aliases and configure ordering, etc. See the [CONFIGURATION.md][CONFIGURATION.md] for more details. [CONFIGURATION.md]: ../../../docs/CONFIGURATION.md#plugins ## Configuration ```toml @sample.conf # Suricata stats and alerts plugin [[inputs.suricata]] ## Source ## Data sink for Suricata stats log. This is expected to be a filename of a ## unix socket to be created for listening. # source = "/var/run/suricata-stats.sock" ## Delimiter ## Used for flattening field keys, e.g. subitem "alert" of "detect" becomes ## "detect_alert" when delimiter is "_". # delimiter = "_" ## Metric version ## Version 1 only collects stats and optionally will look for alerts if ## the configuration setting alerts is set to true. ## Version 2 parses any event type message by default and produced metrics ## under a single metric name using a tag to differentiate between event ## types. The timestamp for the message is applied to the generated metric. ## Additional tags and fields are included as well. # version = "1" ## Alerts ## In metric version 1, only status is captured by default, alerts must be ## turned on with this configuration option. This option does not apply for ## metric version 2. # alerts = false ``` ## Metrics Fields in the 'suricata' measurement follow the JSON format used by Suricata's stats output. See for more information. All fields for Suricata stats are numeric. - suricata - tags: - thread: `Global` for global statistics (if enabled), thread IDs (e.g. `W#03-enp0s31f6`) for thread-specific statistics - fields: - app_layer_flow_dcerpc_udp - app_layer_flow_dns_tcp - app_layer_flow_dns_udp - app_layer_flow_enip_udp - app_layer_flow_failed_tcp - app_layer_flow_failed_udp - app_layer_flow_http - app_layer_flow_ssh - app_layer_flow_tls - app_layer_tx_dns_tcp - app_layer_tx_dns_udp - app_layer_tx_enip_udp - app_layer_tx_http - app_layer_tx_smtp - capture_kernel_drops - capture_kernel_packets - decoder_avg_pkt_size - decoder_bytes - decoder_ethernet - decoder_gre - decoder_icmpv4 - decoder_icmpv4_ipv4_unknown_ver - decoder_icmpv6 - decoder_invalid - decoder_ipv4 - decoder_ipv6 - decoder_max_pkt_size - decoder_pkts - decoder_tcp - decoder_tcp_hlen_too_small - decoder_tcp_invalid_optlen - decoder_teredo - decoder_udp - decoder_vlan - detect_alert - dns_memcap_global - dns_memuse - flow_memuse - flow_mgr_closed_pruned - flow_mgr_est_pruned - flow_mgr_flows_checked - flow_mgr_flows_notimeout - flow_mgr_flows_removed - flow_mgr_flows_timeout - flow_mgr_flows_timeout_inuse - flow_mgr_new_pruned - flow_mgr_rows_checked - flow_mgr_rows_empty - flow_mgr_rows_maxlen - flow_mgr_rows_skipped - flow_spare - flow_tcp_reuse - http_memuse - tcp_memuse - tcp_pseudo - tcp_reassembly_gap - tcp_reassembly_memuse - tcp_rst - tcp_sessions - tcp_syn - tcp_synack - ... Some fields of the Suricata alerts are strings, for example the signatures. See the Suricata [event docs][1] for more information. - suricata_alert - fields: - action - gid - severity - signature - source_ip - source_port - target_port - target_port - ... [1]: https://suricata.readthedocs.io/en/suricata-6.0.0/output/eve/eve-json-format.html?highlight=priority#event-type-alert ### Suricata configuration Suricata needs to deliver the 'stats' event type to a given unix socket for this plugin to pick up. This can be done, for example, by creating an additional output in the Suricata configuration file: ```yaml - eve-log: enabled: yes filetype: unix_stream filename: /tmp/suricata-stats.sock types: - stats: threads: yes ``` ### FreeBSD tuning Under FreeBSD it is necessary to increase the localhost buffer space to at least 16384, default is 8192 otherwise messages from Suricata are truncated as they exceed the default available buffer space, consequently no statistics are processed by the plugin. ```text sysctl -w net.local.stream.recvspace=16384 sysctl -w net.local.stream.sendspace=16384 ``` ## Example Output ```text suricata,host=myhost,thread=FM#01 flow_mgr_rows_empty=0,flow_mgr_rows_checked=65536,flow_mgr_closed_pruned=0,flow_emerg_mode_over=0,flow_mgr_flows_timeout_inuse=0,flow_mgr_rows_skipped=65535,flow_mgr_bypassed_pruned=0,flow_mgr_flows_removed=0,flow_mgr_est_pruned=0,flow_mgr_flows_notimeout=1,flow_mgr_flows_checked=1,flow_mgr_rows_busy=0,flow_spare=10000,flow_mgr_rows_maxlen=1,flow_mgr_new_pruned=0,flow_emerg_mode_entered=0,flow_tcp_reuse=0,flow_mgr_flows_timeout=0 1568368562545197545 suricata,host=myhost,thread=W#04-wlp4s0 decoder_ltnull_pkt_too_small=0,decoder_ipraw_invalid_ip_version=0,defrag_ipv4_reassembled=0,tcp_no_flow=0,app_layer_flow_tls=1,decoder_udp=25,defrag_ipv6_fragments=0,defrag_ipv4_fragments=0,decoder_tcp=59,decoder_vlan=0,decoder_pkts=84,decoder_vlan_qinq=0,decoder_avg_pkt_size=574,flow_memcap=0,defrag_max_frag_hits=0,tcp_ssn_memcap_drop=0,capture_kernel_packets=84,app_layer_flow_dcerpc_udp=0,app_layer_tx_dns_tcp=0,tcp_rst=0,decoder_icmpv4=0,app_layer_tx_tls=0,decoder_ipv4=84,decoder_erspan=0,decoder_ltnull_unsupported_type=0,decoder_invalid=0,app_layer_flow_ssh=0,capture_kernel_drops=0,app_layer_flow_ftp=0,app_layer_tx_http=0,tcp_pseudo_failed=0,defrag_ipv6_reassembled=0,defrag_ipv6_timeouts=0,tcp_pseudo=0,tcp_sessions=1,decoder_ethernet=84,decoder_raw=0,decoder_sctp=0,app_layer_flow_dns_udp=1,decoder_gre=0,app_layer_flow_http=0,app_layer_flow_imap=0,tcp_segment_memcap_drop=0,detect_alert=0,app_layer_flow_failed_tcp=0,decoder_teredo=0,decoder_mpls=0,decoder_ppp=0,decoder_max_pkt_size=1422,decoder_ipv6=0,tcp_reassembly_gap=0,app_layer_flow_dcerpc_tcp=0,decoder_ipv4_in_ipv6=0,tcp_stream_depth_reached=0,app_layer_flow_dns_tcp=0,app_layer_flow_smtp=0,tcp_syn=1,decoder_sll=0,tcp_invalid_checksum=0,app_layer_tx_dns_udp=1,decoder_bytes=48258,defrag_ipv4_timeouts=0,app_layer_flow_msn=0,decoder_pppoe=0,decoder_null=0,app_layer_flow_failed_udp=3,app_layer_tx_smtp=0,decoder_icmpv6=0,decoder_ipv6_in_ipv6=0,tcp_synack=1,app_layer_flow_smb=0,decoder_dce_pkt_too_small=0 1568368562545174807 suricata,host=myhost,thread=W#01-wlp4s0 tcp_synack=0,app_layer_flow_imap=0,decoder_ipv4_in_ipv6=0,decoder_max_pkt_size=684,decoder_gre=0,defrag_ipv4_timeouts=0,tcp_invalid_checksum=0,decoder_ipv4=53,flow_memcap=0,app_layer_tx_http=0,app_layer_tx_smtp=0,decoder_null=0,tcp_no_flow=0,app_layer_tx_tls=0,app_layer_flow_ssh=0,app_layer_flow_smtp=0,decoder_pppoe=0,decoder_teredo=0,decoder_ipraw_invalid_ip_version=0,decoder_ltnull_pkt_too_small=0,tcp_rst=0,decoder_ppp=0,decoder_ipv6=29,app_layer_flow_dns_udp=3,decoder_vlan=0,app_layer_flow_dcerpc_tcp=0,tcp_syn=0,defrag_ipv4_fragments=0,defrag_ipv6_timeouts=0,decoder_raw=0,defrag_ipv6_reassembled=0,tcp_reassembly_gap=0,tcp_sessions=0,decoder_udp=44,tcp_segment_memcap_drop=0,app_layer_tx_dns_udp=3,app_layer_flow_tls=0,decoder_tcp=37,defrag_ipv4_reassembled=0,app_layer_flow_failed_udp=6,app_layer_flow_ftp=0,decoder_icmpv6=1,tcp_stream_depth_reached=0,capture_kernel_drops=0,decoder_sll=0,decoder_bytes=15883,decoder_ethernet=91,tcp_pseudo=0,app_layer_flow_http=0,decoder_sctp=0,decoder_pkts=91,decoder_avg_pkt_size=174,decoder_erspan=0,app_layer_flow_msn=0,app_layer_flow_smb=0,capture_kernel_packets=91,decoder_icmpv4=0,decoder_ipv6_in_ipv6=0,tcp_ssn_memcap_drop=0,decoder_vlan_qinq=0,decoder_ltnull_unsupported_type=0,decoder_invalid=0,defrag_max_frag_hits=0,tcp_pseudo_failed=0,detect_alert=0,app_layer_tx_dns_tcp=0,app_layer_flow_failed_tcp=0,app_layer_flow_dcerpc_udp=0,app_layer_flow_dns_tcp=0,defrag_ipv6_fragments=0,decoder_mpls=0,decoder_dce_pkt_too_small=0 1568368562545148438 suricata,host=myhost flow_memuse=7094464,tcp_memuse=3276800,tcp_reassembly_memuse=12332832,dns_memuse=0,dns_memcap_state=0,dns_memcap_global=0,http_memuse=0,http_memcap=0 1568368562545144569 suricata,host=myhost,thread=W#07-wlp4s0 app_layer_tx_http=0,app_layer_tx_dns_tcp=0,decoder_vlan=0,decoder_pppoe=0,decoder_sll=0,decoder_tcp=0,flow_memcap=0,app_layer_flow_msn=0,tcp_no_flow=0,tcp_rst=0,tcp_segment_memcap_drop=0,tcp_sessions=0,detect_alert=0,defrag_ipv6_reassembled=0,decoder_ipraw_invalid_ip_version=0,decoder_erspan=0,decoder_icmpv4=0,app_layer_tx_dns_udp=2,decoder_ltnull_pkt_too_small=0,decoder_bytes=1998,decoder_ipv6=1,defrag_ipv4_fragments=0,defrag_ipv6_fragments=0,app_layer_tx_smtp=0,decoder_ltnull_unsupported_type=0,decoder_max_pkt_size=342,app_layer_flow_ftp=0,decoder_ipv6_in_ipv6=0,defrag_ipv4_reassembled=0,defrag_ipv6_timeouts=0,app_layer_flow_dns_tcp=0,decoder_avg_pkt_size=181,defrag_ipv4_timeouts=0,tcp_stream_depth_reached=0,decoder_mpls=0,app_layer_flow_dns_udp=2,tcp_ssn_memcap_drop=0,app_layer_flow_dcerpc_tcp=0,app_layer_flow_failed_udp=2,app_layer_flow_smb=0,app_layer_flow_failed_tcp=0,decoder_invalid=0,decoder_null=0,decoder_gre=0,decoder_ethernet=11,app_layer_flow_ssh=0,defrag_max_frag_hits=0,capture_kernel_drops=0,tcp_pseudo_failed=0,app_layer_flow_smtp=0,decoder_udp=10,decoder_sctp=0,decoder_teredo=0,decoder_icmpv6=1,tcp_pseudo=0,tcp_synack=0,app_layer_tx_tls=0,app_layer_flow_imap=0,capture_kernel_packets=11,decoder_pkts=11,decoder_raw=0,decoder_ppp=0,tcp_syn=0,tcp_invalid_checksum=0,app_layer_flow_tls=0,decoder_ipv4_in_ipv6=0,app_layer_flow_http=0,decoder_dce_pkt_too_small=0,decoder_ipv4=10,decoder_vlan_qinq=0,tcp_reassembly_gap=0,app_layer_flow_dcerpc_udp=0 1568368562545110847 suricata,host=myhost,thread=W#06-wlp4s0 app_layer_tx_smtp=0,decoder_ipv6_in_ipv6=0,decoder_dce_pkt_too_small=0,tcp_segment_memcap_drop=0,tcp_sessions=1,decoder_ppp=0,tcp_pseudo_failed=0,app_layer_tx_dns_tcp=0,decoder_invalid=0,defrag_ipv4_timeouts=0,app_layer_flow_smb=0,app_layer_flow_ssh=0,decoder_bytes=19407,decoder_null=0,app_layer_flow_tls=1,decoder_avg_pkt_size=473,decoder_pkts=41,decoder_pppoe=0,decoder_tcp=32,defrag_ipv4_reassembled=0,tcp_reassembly_gap=0,decoder_raw=0,flow_memcap=0,defrag_ipv6_timeouts=0,app_layer_flow_smtp=0,app_layer_tx_http=0,decoder_sll=0,decoder_udp=8,decoder_ltnull_pkt_too_small=0,decoder_ltnull_unsupported_type=0,decoder_ipv4_in_ipv6=0,decoder_vlan=0,decoder_max_pkt_size=1422,tcp_no_flow=0,app_layer_flow_failed_tcp=0,app_layer_flow_dns_tcp=0,app_layer_flow_ftp=0,decoder_icmpv4=0,defrag_max_frag_hits=0,tcp_rst=0,app_layer_flow_msn=0,app_layer_flow_failed_udp=2,app_layer_flow_dns_udp=0,app_layer_flow_dcerpc_udp=0,decoder_ipv4=39,decoder_ethernet=41,defrag_ipv6_reassembled=0,tcp_ssn_memcap_drop=0,app_layer_tx_tls=0,decoder_gre=0,decoder_vlan_qinq=0,tcp_pseudo=0,app_layer_flow_imap=0,app_layer_flow_dcerpc_tcp=0,defrag_ipv4_fragments=0,defrag_ipv6_fragments=0,tcp_synack=1,app_layer_flow_http=0,app_layer_tx_dns_udp=0,capture_kernel_packets=41,decoder_ipv6=2,tcp_invalid_checksum=0,tcp_stream_depth_reached=0,decoder_ipraw_invalid_ip_version=0,decoder_icmpv6=1,tcp_syn=1,detect_alert=0,capture_kernel_drops=0,decoder_teredo=0,decoder_erspan=0,decoder_sctp=0,decoder_mpls=0 1568368562545084670 suricata,host=myhost,thread=W#02-wlp4s0 decoder_tcp=53,tcp_rst=3,tcp_reassembly_gap=0,defrag_ipv6_timeouts=0,tcp_ssn_memcap_drop=0,app_layer_flow_dcerpc_tcp=0,decoder_max_pkt_size=1422,decoder_ipv6_in_ipv6=0,tcp_no_flow=0,app_layer_flow_ftp=0,app_layer_flow_ssh=0,decoder_pkts=82,decoder_sctp=0,tcp_invalid_checksum=0,app_layer_flow_dns_tcp=0,decoder_ipraw_invalid_ip_version=0,decoder_bytes=26441,decoder_erspan=0,tcp_pseudo_failed=0,tcp_syn=1,app_layer_tx_http=0,app_layer_tx_smtp=0,decoder_teredo=0,decoder_ipv4=80,defrag_ipv4_fragments=0,tcp_stream_depth_reached=0,app_layer_flow_smb=0,capture_kernel_packets=82,decoder_null=0,decoder_ltnull_pkt_too_small=0,decoder_ppp=0,decoder_icmpv6=1,app_layer_flow_dns_udp=2,app_layer_flow_http=0,app_layer_tx_dns_udp=3,decoder_mpls=0,decoder_sll=0,defrag_ipv4_reassembled=0,tcp_segment_memcap_drop=0,app_layer_flow_imap=0,decoder_ltnull_unsupported_type=0,decoder_icmpv4=0,decoder_raw=0,defrag_ipv4_timeouts=0,app_layer_flow_failed_udp=8,decoder_gre=0,capture_kernel_drops=0,defrag_ipv6_reassembled=0,tcp_pseudo=0,app_layer_flow_tls=1,decoder_avg_pkt_size=322,decoder_dce_pkt_too_small=0,decoder_ethernet=82,defrag_ipv6_fragments=0,tcp_sessions=1,tcp_synack=1,app_layer_tx_dns_tcp=0,decoder_vlan=0,flow_memcap=0,decoder_vlan_qinq=0,decoder_udp=28,decoder_invalid=0,detect_alert=0,app_layer_flow_failed_tcp=0,app_layer_tx_tls=0,decoder_pppoe=0,decoder_ipv6=2,decoder_ipv4_in_ipv6=0,defrag_max_frag_hits=0,app_layer_flow_dcerpc_udp=0,app_layer_flow_smtp=0,app_layer_flow_msn=0 1568368562545061864 suricata,host=myhost,thread=W#08-wlp4s0 decoder_dce_pkt_too_small=0,app_layer_tx_dns_tcp=0,decoder_pkts=58,decoder_ppp=0,decoder_raw=0,decoder_ipv4_in_ipv6=0,decoder_max_pkt_size=1392,tcp_invalid_checksum=0,tcp_syn=0,decoder_ipv4=51,decoder_ipv6_in_ipv6=0,decoder_tcp=0,decoder_ltnull_pkt_too_small=0,flow_memcap=0,decoder_udp=58,tcp_ssn_memcap_drop=0,tcp_pseudo=0,app_layer_flow_dcerpc_udp=0,app_layer_flow_dns_udp=5,app_layer_tx_http=0,capture_kernel_drops=0,decoder_vlan=0,tcp_segment_memcap_drop=0,app_layer_flow_ftp=0,app_layer_flow_imap=0,app_layer_flow_http=0,app_layer_flow_tls=0,decoder_icmpv4=0,decoder_sctp=0,defrag_ipv4_timeouts=0,tcp_reassembly_gap=0,detect_alert=0,decoder_ethernet=58,tcp_pseudo_failed=0,decoder_teredo=0,defrag_ipv4_reassembled=0,tcp_sessions=0,app_layer_flow_msn=0,decoder_ipraw_invalid_ip_version=0,tcp_no_flow=0,app_layer_flow_dns_tcp=0,decoder_null=0,defrag_ipv4_fragments=0,app_layer_flow_dcerpc_tcp=0,app_layer_flow_failed_udp=8,app_layer_tx_tls=0,decoder_bytes=15800,decoder_ipv6=7,tcp_stream_depth_reached=0,decoder_invalid=0,decoder_ltnull_unsupported_type=0,app_layer_tx_dns_udp=6,decoder_pppoe=0,decoder_avg_pkt_size=272,decoder_erspan=0,defrag_ipv6_timeouts=0,app_layer_flow_failed_tcp=0,decoder_gre=0,decoder_sll=0,defrag_max_frag_hits=0,app_layer_flow_ssh=0,capture_kernel_packets=58,decoder_mpls=0,decoder_vlan_qinq=0,tcp_rst=0,app_layer_flow_smb=0,app_layer_tx_smtp=0,decoder_icmpv6=0,defrag_ipv6_fragments=0,defrag_ipv6_reassembled=0,tcp_synack=0,app_layer_flow_smtp=0 1568368562545035575 suricata,host=myhost,thread=W#05-wlp4s0 tcp_reassembly_gap=0,capture_kernel_drops=0,decoder_ltnull_unsupported_type=0,tcp_sessions=0,tcp_stream_depth_reached=0,tcp_pseudo_failed=0,app_layer_flow_failed_tcp=0,app_layer_tx_dns_tcp=0,decoder_null=0,decoder_dce_pkt_too_small=0,decoder_udp=7,tcp_rst=3,app_layer_flow_dns_tcp=0,decoder_invalid=0,defrag_ipv4_reassembled=0,tcp_synack=0,app_layer_flow_ftp=0,decoder_bytes=3117,decoder_pppoe=0,app_layer_flow_dcerpc_tcp=0,app_layer_flow_smb=0,decoder_ipv6_in_ipv6=0,decoder_ipraw_invalid_ip_version=0,app_layer_flow_imap=0,app_layer_tx_dns_udp=2,decoder_ppp=0,decoder_ipv4=21,decoder_tcp=14,flow_memcap=0,tcp_syn=0,tcp_invalid_checksum=0,decoder_teredo=0,decoder_ltnull_pkt_too_small=0,defrag_max_frag_hits=0,app_layer_tx_tls=0,decoder_pkts=24,decoder_sll=0,defrag_ipv6_fragments=0,app_layer_flow_dcerpc_udp=0,app_layer_flow_smtp=0,decoder_icmpv6=3,defrag_ipv6_timeouts=0,decoder_ipv6=3,decoder_raw=0,defrag_ipv6_reassembled=0,tcp_no_flow=0,detect_alert=0,app_layer_flow_tls=0,decoder_ethernet=24,decoder_vlan=0,decoder_icmpv4=0,decoder_ipv4_in_ipv6=0,app_layer_flow_failed_udp=1,decoder_mpls=0,decoder_max_pkt_size=653,decoder_sctp=0,defrag_ipv4_timeouts=0,tcp_ssn_memcap_drop=0,app_layer_flow_dns_udp=1,app_layer_tx_smtp=0,capture_kernel_packets=24,decoder_vlan_qinq=0,decoder_gre=0,app_layer_flow_ssh=0,app_layer_flow_msn=0,defrag_ipv4_fragments=0,app_layer_flow_http=0,tcp_segment_memcap_drop=0,tcp_pseudo=0,app_layer_tx_http=0,decoder_erspan=0,decoder_avg_pkt_size=129 1568368562545009684 suricata,host=myhost,thread=W#03-wlp4s0 app_layer_flow_failed_tcp=0,decoder_teredo=0,decoder_ipv6_in_ipv6=0,tcp_pseudo_failed=0,tcp_stream_depth_reached=0,tcp_syn=0,decoder_gre=0,tcp_segment_memcap_drop=0,tcp_ssn_memcap_drop=0,app_layer_tx_smtp=0,decoder_raw=0,decoder_ltnull_pkt_too_small=0,tcp_sessions=0,tcp_reassembly_gap=0,app_layer_flow_ssh=0,app_layer_flow_imap=0,decoder_ipv4=463,decoder_ethernet=463,capture_kernel_packets=463,decoder_pppoe=0,defrag_ipv4_reassembled=0,app_layer_flow_tls=0,app_layer_flow_dcerpc_udp=0,app_layer_flow_dns_udp=0,decoder_vlan=0,decoder_ipraw_invalid_ip_version=0,decoder_mpls=0,tcp_no_flow=0,decoder_avg_pkt_size=445,decoder_udp=432,flow_memcap=0,app_layer_tx_dns_udp=0,app_layer_flow_msn=0,app_layer_flow_http=0,app_layer_flow_dcerpc_tcp=0,decoder_ipv6=0,decoder_ipv4_in_ipv6=0,defrag_ipv4_timeouts=0,defrag_ipv4_fragments=0,defrag_ipv6_timeouts=0,decoder_sctp=0,defrag_ipv6_fragments=0,app_layer_flow_dns_tcp=0,app_layer_tx_tls=0,defrag_max_frag_hits=0,decoder_bytes=206345,decoder_vlan_qinq=0,decoder_invalid=0,decoder_ppp=0,tcp_rst=0,detect_alert=0,capture_kernel_drops=0,app_layer_flow_failed_udp=4,decoder_null=0,decoder_icmpv4=0,decoder_icmpv6=0,decoder_ltnull_unsupported_type=0,defrag_ipv6_reassembled=0,tcp_invalid_checksum=0,tcp_synack=0,decoder_tcp=31,tcp_pseudo=0,app_layer_flow_smb=0,app_layer_flow_smtp=0,decoder_max_pkt_size=1463,decoder_dce_pkt_too_small=0,app_layer_tx_http=0,decoder_pkts=463,decoder_sll=0,app_layer_flow_ftp=0,app_layer_tx_dns_tcp=0,decoder_erspan=0 1568368562544966078 ```