Add system socket MetricSet

The system.socket metricset reports an event for each new TCP socket that it
sees. It does this by polling the kernel to get a dump of all sockets.
So using a short polling interval with this metricset is important to
not miss short lived connections.

The metricset reports the process that has the socket open. It does this
by associating the socket's inode to the process that has a file
descriptor open pointing to the socket's inode. It reads /proc and
/proc/<pid>/fd just prior to polling the kernel to get all sockets.

A reverse lookup can be performed by the metricset on the remote IP and the
returned hostname will be added to the event and cached. The is disabled by
default and can be enabled through the configuration.  If a hostname is found
then the eTLD+1 (effective top-level domain plus one level) value will also be
added to the event.

For the IP address fields the index template for Elasticsearch 5.x uses
the ip field type. But for Elasticsearch 2.x it uses string because the
ip field type in 2.x does not support IPv6 addresses.

CHANGELOG.asciidoc

@@ -57,6 +57,7 @@ https://github.com/elastic/beats/compare/v5.1.1...master[Check the HEAD diff]
 - Add a couchbase module with metricsets for node, cluster and bucket. {pull}3081[3081]
 - Export number of cores for cpu module. {pull}3192[3192]
 - Experimental Prometheus module. {pull}3202[3202]
+- Add system socket module that reports all TCP sockets. {pull}3246[3246]
 
 *Packetbeat*
 

libbeat/scripts/generate_template.py

@@ -205,6 +205,18 @@ def fill_field_properties(args, field, defaults, path):
                 "ignore_above": 1024
             }
 
+    elif field["type"] == "ip":
+        if args.es2x:
+            properties[field["name"]] = {
+                "type": "string",
+                "index": "not_analyzed",
+                "ignore_above": 1024
+            }
+        else:
+            properties[field["name"]] = {
+                "type": "ip"
+            }
+
     elif field["type"] in ["geo_point", "date", "long", "integer",
                            "double", "float", "half_float", "scaled_float",
                            "boolean"]:

metricbeat/_meta/beat.full.yml

@@ -39,6 +39,9 @@ metricbeat.modules:
 
     # Per process stats
     - process
+
+    # Sockets and connection info (linux only)
+    #- socket
   enabled: true
   period: 10s
   processes: ['.*']
@@ -49,6 +52,11 @@ metricbeat.modules:
   # EXPERIMENTAL: cgroups can be enabled for the process metricset.
   #cgroups: false
 
+  # Configure reverse DNS lookup on remote IP addresses in the socket metricset.
+  #socket.reverse_lookup.enabled: false
+  #socket.reverse_lookup.success_ttl: 60s
+  #socket.reverse_lookup.failure_ttl: 60s
+
 #------------------------------- Apache Module -------------------------------
 #- module: apache
   #metricsets: ["status"]

metricbeat/_meta/beat.yml

@@ -39,6 +39,9 @@ metricbeat.modules:
 
     # Per process stats
     - process
+
+    # Sockets (linux only)
+    #- socket
   enabled: true
   period: 10s
   processes: ['.*']

metricbeat/docs/fields.asciidoc

@@ -6206,6 +6206,148 @@ type: long
 Total number of I/O operations performed on all devices by processes in the cgroup as seen by the throttling policy.
 
 
+[float]
+== socket Fields
+
+TCP sockets that are active.
+
+
+
+[float]
+=== system.socket.direction
+
+type: keyword
+
+example: incoming
+
+How the socket was initiated. Possible values are incoming, outgoing, or listening.
+
+
+[float]
+=== system.socket.family
+
+type: keyword
+
+example: ipv4
+
+Address family.
+
+
+[float]
+=== system.socket.local.ip
+
+type: ip
+
+example: 192.0.2.1 or 2001:0DB8:ABED:8536::1
+
+Local IP address. This can be an IPv4 or IPv6 address.
+
+
+[float]
+=== system.socket.local.port
+
+type: long
+
+example: 22
+
+Local port.
+
+
+[float]
+=== system.socket.remote.ip
+
+type: ip
+
+example: 192.0.2.1 or 2001:0DB8:ABED:8536::1
+
+Remote IP address. This can be an IPv4 or IPv6 address
+
+
+[float]
+=== system.socket.remote.port
+
+type: long
+
+example: 22
+
+Remote port.
+
+
+[float]
+=== system.socket.remote.host
+
+type: keyword
+
+example: 76-211-117-36.nw.example.com.
+
+PTR record associated with the remote IP. It is obtained via reverse IP lookup.
+
+
+[float]
+=== system.socket.remote.etld_plus_one
+
+type: keyword
+
+example: example.com.
+
+The effective top-level domain (eTLD) of the remote host plus one more label. For example, the eTLD+1 for "foo.bar.golang.org." is "golang.org.". The data for determining the eTLD comes from an embedded copy of the data from http://publicsuffix.org.
+
+
+[float]
+=== system.socket.remote.host_error
+
+type: keyword
+
+Error describing the cause of the reverse lookup failure.
+
+
+[float]
+=== system.socket.process.pid
+
+type: long
+
+ID of the process that opened the socket.
+
+
+[float]
+=== system.socket.process.command
+
+type: keyword
+
+Name of the command (limited to 20 chars by the OS).
+
+
+[float]
+=== system.socket.process.cmdline
+
+type: keyword
+
+
+
+[float]
+=== system.socket.process.exe
+
+type: keyword
+
+Absolute path to the executable.
+
+
+[float]
+=== system.socket.user.id
+
+type: long
+
+UID of the user running the process.
+
+
+[float]
+=== system.socket.user.name
+
+type: keyword
+
+Name of the user running the process.
+
+
 [[exported-fields-zookeeper]]
 == ZooKeeper Fields
 

metricbeat/docs/modules/system.asciidoc

@@ -93,6 +93,9 @@ metricbeat.modules:
 
     # Per process stats
     - process
+
+    # Sockets (linux only)
+    #- socket
   enabled: true
   period: 10s
   processes: ['.*']
@@ -121,6 +124,8 @@ The following metricsets are available:
 
 * <<metricbeat-metricset-system-process,process>>
 
+* <<metricbeat-metricset-system-socket,socket>>
+
 include::system/core.asciidoc[]
 
 include::system/cpu.asciidoc[]
@@ -139,3 +144,5 @@ include::system/network.asciidoc[]
 
 include::system/process.asciidoc[]
 
+include::system/socket.asciidoc[]
+

metricbeat/docs/modules/system/socket.asciidoc

@@ -0,0 +1,19 @@
+////
+This file is generated! See scripts/docs_collector.py
+////
+
+[[metricbeat-metricset-system-socket]]
+include::../../../module/system/socket/_meta/docs.asciidoc[]
+
+
+==== Fields
+
+For a description of each field in the metricset, see the
+<<exported-fields-system,exported fields>> section.
+
+Here is an example document generated by this metricset:
+
+[source,json]
+----
+include::../../../module/system/socket/_meta/data.json[]
+----

metricbeat/include/list.go

@@ -52,6 +52,7 @@ import (
 	_ "github.com/elastic/beats/metricbeat/module/system/memory"
 	_ "github.com/elastic/beats/metricbeat/module/system/network"
 	_ "github.com/elastic/beats/metricbeat/module/system/process"
+	_ "github.com/elastic/beats/metricbeat/module/system/socket"
 	_ "github.com/elastic/beats/metricbeat/module/zookeeper"
 	_ "github.com/elastic/beats/metricbeat/module/zookeeper/mntr"
 )

metricbeat/mb/testing/data_generator.go

@@ -3,6 +3,7 @@ package testing
 import (
 	"encoding/json"
 	"flag"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"testing"
@@ -33,15 +34,18 @@ func WriteEvent(f mb.EventFetcher, t *testing.T) error {
 }
 
 func WriteEvents(f mb.EventsFetcher, t *testing.T) error {
-
 	if !*dataFlag {
 		t.Skip("Skip data generation tests")
 	}
+
 	events, err := f.Fetch()
 	if err != nil {
 		return err
 	}
 
+	if len(events) == 0 {
+		return fmt.Errorf("no events were generated")
+	}
 	return createEvent(events[0], f)
 }
 

metricbeat/metricbeat.full.yml

@@ -39,6 +39,9 @@ metricbeat.modules:
 
     # Per process stats
     - process
+
+    # Sockets and connection info (linux only)
+    #- socket
   enabled: true
   period: 10s
   processes: ['.*']
@@ -49,6 +52,11 @@ metricbeat.modules:
   # EXPERIMENTAL: cgroups can be enabled for the process metricset.
   #cgroups: false
 
+  # Configure reverse DNS lookup on remote IP addresses in the socket metricset.
+  #socket.reverse_lookup.enabled: false
+  #socket.reverse_lookup.success_ttl: 60s
+  #socket.reverse_lookup.failure_ttl: 60s
+
 #------------------------------- Apache Module -------------------------------
 #- module: apache
   #metricsets: ["status"]