initial push to github

.github/workflows/docker-hub-build-push.yml

@@ -0,0 +1,25 @@
+name: build docker image and push to docker hub
+
+on:
+  release:
+    types: # This configuration does not affect the page_build event above
+      - created
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout code
+        uses: actions/checkout@v2
+      - name: install buildx
+        id: buildx
+        uses: crazy-max/ghaction-docker-buildx@v1
+        with:
+          version: latest
+      - name: login to docker hub
+        run: echo "${{ secrets.DOCKER_PASSWORD }}" | docker login -u "${{ secrets.DOCKER_USERNAME }}" --password-stdin
+      - name: build the image
+        run: |
+          docker buildx build --push \
+            --tag shizunge/endlessh-go:latest \
+            --platform linux/amd64,linux/arm/v7,linux/arm64 .

Dockerfile

@@ -0,0 +1,19 @@
+FROM golang:alpine AS build
+
+ADD . /go/src/app
+WORKDIR /go/src/app
+RUN go mod tidy
+RUN go build -o endlessh .
+
+FROM alpine:latest
+
+LABEL org.opencontainers.image.title=endlessh-go
+LABEL org.opencontainers.image.description="Endlessh: an SSH tarpit"
+LABEL org.opencontainers.image.vendor="Shizun Ge"
+LABEL org.opencontainers.image.licenses=GPLv3
+
+COPY --from=build /go/src/app/endlessh /usr/bin/endlessh
+EXPOSE 2222 2112
+USER nobody
+ENTRYPOINT  ["/usr/bin/endlessh"]
+CMD ["-logtostderr", "-v=1"]

LICENSE

@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
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+  The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

README.md

@@ -0,0 +1,96 @@
+# endlessh-go
+
+Golang implementation of [endlessh](https://nullprogram.com/blog/2019/03/22/) exporting Prometheus metrics.
+
+## Introduction
+
+Endlessh is a great idea that not only blocks the brute force SSH attacks, but also wastes attackers time as a kind of counter-attack. Besides trapping the attackers, I also want to virtualize the Geolocations and other statistics of the sources of attacks. Unfortunately the wonderful [C implementation of endlessh](https://github.com/skeeto/endlessh) only provides text based log, but I do not like the solution that writing extra scripts to parse the log outputs, then exporting the results to a dashboard, because it would introduce extra layers in my current setup and it would depend on the format of the text log file rather than some structured data. Thus I create this golang implementation of endlessh to export [Prometheus](https://prometheus.io/) metrics and a [Grafana](https://grafana.com/) dashboard to virtualize them.
+
+If you want a dashboard of sources of attacks and do not mind the endlessh server, besides trapping the attackers, does extra things including: translating IP to Geohash, exporting Prometheus metrics, and using more memory (about 10MB), this is the solution for you.
+
+## Getting Started
+
+Clone the repo then build from source:
+
+```
+go build .
+./endlessh-go
+```
+
+Alternatively, you can use the [docker image](https://hub.docker.com/r/shizunge/endlessh-go):
+
+```
+sudo docker run -d shizunge/endlessh-go
+```
+
+It listens to port `2222` by default.
+
+If you want log like the [C implementation](https://github.com/skeeto/endlessh), you need to set both CLI arguments `-logtostderr` and `-v=1`, then the log will go to the stderr. You can set different log destinations via CLI arguments.
+
+## Usage
+
+Usage of `./endlessh-go`
+
+* -alsologtostderr
+  * log to standard error as well as files
+* -conn_type string
+  * Connection type. Possible values are tcp, tcp4, tcp6 (default "tcp")
+* -enable_prometheus
+  * Enable prometheus
+* -geoip_supplier string
+  * Supplier to obtain Geohash of IPs. Possible values are "off", "ip-api", "freegeoip" (default "off")
+* -host string
+  * Listening address (default "0.0.0.0")
+* -interval_ms int
+  * Message millisecond delay (default 1000)
+* -line_length int
+  * Maximum banner line length (default 32)
+* -log_backtrace_at value
+  * when logging hits line file:N, emit a stack trace
+* -log_dir string
+  * If non-empty, write log files in this directory
+* -logtostderr
+  * log to standard error instead of files
+* -max_clients int
+  * Maximum number of clients (default 4096)
+* -port string
+  * Listening port (default "2222")
+* -prometheus_entry string
+  * Entry point for prometheus (default "metrics")
+* -prometheus_port string
+  * The port for prometheus (default "2112")
+* -stderrthreshold value
+  * logs at or above this threshold go to stderr
+* -v value
+  * log level for V logs
+* -vmodule value
+  * comma-separated list of pattern=N settings for file-filtered logging
+
+## Metrics
+
+This golang implementation exports the following Prometheus metrics.
+
+| Metric                               | Type  | Description  |
+|--------------------------------------|-------|--------------|
+| endlessh_client_open_count_total     | count | Total number of clients that tried to connect to this host. |
+| endlessh_client_closed_count_total   | count | Total number of clients that stopped connecting to this host. |
+| endlessh_sent_bytes_total            | count | Total bytes sent to clients that tried to connect to this host. |
+| endlessh_trapped_time_seconds_total  | count | Total seconds clients spent on endlessh. |
+| endlessh_client_open_count           | count | Number of connections of clients. <br> Labals: <br> <ul><li> `ip`: IP of the client </li> <li>  `country`: Country of the IP </li> <li>  `location`: Country, Region, and City </li> <li>  `geohash`: Geohash of the location </li></ul> |
+| endlessh_client_trapped_time_seconds | count | Seconds a client spends on endlessh. <br> Labals: <br> <ul><li>  `ip`: IP of the client </li></ul> |
+
+The metrics is off by default, you can turn it via the CLI argument `-enable_prometheus`.
+
+It listens to port `2112` and entry point is `/metrics` by default. The port and entry point can be changed via CLI arguments.
+
+The endlessh-go server stores the geohash of attackers as a label on `endlessh_client_open_count`, which is also off by default. You can turn it on via the CLI argument `-geoip_supplier`. The endlessh-go uses service from either [ip-api](https://ip-api.com/) or [freegeoip](https://freegeoip.live/), which may enforce a query rate and limit commercial use. Visit their website for their terms and policies.
+
+## Dashboard
+
+![screenshot](dashboard/screenshot.png)
+
+The dashboard requires Grafana 8.2.
+
+You can import the dashboard from Grafana.com using ID [15156](https://grafana.com/grafana/dashboards/15156)
+
+The IP addresses are clickable and link you to the [ARIN](https://www.arin.net/) database.

client.go

@@ -0,0 +1,105 @@
+// Copyright (C) 2021 Shizun Ge
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+package main
+
+import (
+	"math/rand"
+	"net"
+	"sync/atomic"
+	"time"
+
+	"github.com/golang/glog"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var letterBytes = []byte(" abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890!@#$%^&*()-=_+[]{}|;:',./<>?")
+
+func randStringBytes(n int64) []byte {
+	b := make([]byte, n+1)
+	for i := range b {
+		b[i] = letterBytes[rand.Intn(len(letterBytes))]
+	}
+	b[n] = '\n'
+	return b
+}
+
+type client struct {
+	conn          net.Conn
+	last          time.Time
+	next          time.Time
+	start         time.Time
+	interval      time.Duration
+	geoipSupplier string
+	geohash       string
+	country       string
+	location      string
+	bytes_sent    int
+}
+
+func NewClient(conn net.Conn, interval time.Duration, maxClient int64, geoipSupplier string) *client {
+	addr := conn.RemoteAddr().(*net.TCPAddr)
+	atomic.AddInt64(&numCurrentClients, 1)
+	atomic.AddInt64(&numTotalClients, 1)
+	geohash, country, location, err := geohashAndLocation(addr.IP.String(), geoipSupplier)
+	if err != nil {
+		glog.Warningf("Failed to obatin the geohash of %v: %v.", addr.IP, err)
+	}
+	clientIP.With(prometheus.Labels{
+		"ip":       addr.IP.String(),
+		"geohash":  geohash,
+		"country":  country,
+		"location": location}).Inc()
+	glog.V(1).Infof("ACCEPT host=%v port=%v n=%v/%v\n", addr.IP, addr.Port, numCurrentClients, maxClient)
+	return &client{
+		conn:       conn,
+		last:       time.Now(),
+		next:       time.Now().Add(interval),
+		start:      time.Now(),
+		interval:   interval,
+		geohash:    geohash,
+		country:    country,
+		location:   location,
+		bytes_sent: 0,
+	}
+}
+
+func (c *client) Send(bannerMaxLength int64) error {
+	defer func(c *client) {
+		addr := c.conn.RemoteAddr().(*net.TCPAddr)
+		millisecondsSpent := time.Now().Sub(c.last).Milliseconds()
+		c.last = time.Now()
+		c.next = time.Now().Add(c.interval)
+		atomic.AddInt64(&numTotalMilliseconds, millisecondsSpent)
+		clientSeconds.With(prometheus.Labels{"ip": addr.IP.String()}).Add(float64(millisecondsSpent) / 1000)
+	}(c)
+	length := rand.Int63n(bannerMaxLength)
+	bytes_sent, err := c.conn.Write(randStringBytes(length))
+	if err != nil {
+		return err
+	}
+	c.bytes_sent += bytes_sent
+	atomic.AddInt64(&numTotalBytes, int64(bytes_sent))
+	return nil
+}
+
+func (c *client) Close() {
+	addr := c.conn.RemoteAddr().(*net.TCPAddr)
+	atomic.AddInt64(&numCurrentClients, -1)
+	atomic.AddInt64(&numTotalClientsClosed, 1)
+	glog.V(1).Infof("CLOSE host=%v port=%v time=%v bytes=%v\n", addr.IP, addr.Port, time.Now().Sub(c.start).Seconds(), c.bytes_sent)
+	c.conn.Close()
+}

geoip.go

@@ -0,0 +1,146 @@
+// Copyright (C) 2021 Shizun Ge
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
+
+	"github.com/pierrre/geohash"
+)
+
+type freegeoip struct {
+	Ip          string  `json:"ip"`
+	CountryCode string  `json:"country_code"`
+	CountryName string  `json:"country_name"`
+	RegionCode  string  `json:"region_code"`
+	RegionName  string  `json:"region_name"`
+	City        string  `json:"city"`
+	Zipcode     string  `json:"zipcode"`
+	Latitude    float64 `json:"latitude"`
+	Longitude   float64 `json:"longitude"`
+	MetroCode   int     `json:"metro_code"`
+	AreaCode    int     `json:"area_code"`
+}
+
+func geohashAndLocationFromFreegeoip(address string) (string, string, string, error) {
+	var geo freegeoip
+	response, err := http.Get("https://freegeoip.live/json/" + address)
+	if err != nil {
+		return "s000", "Unknown", "Unknown", err
+	}
+	defer response.Body.Close()
+
+	body, err := ioutil.ReadAll(response.Body)
+	if err != nil {
+		return "s000", "Unknown", "Unknown", err
+	}
+
+	err = json.Unmarshal(body, &geo)
+	if err != nil {
+		return "s000", "Unknown", "Unknown", err
+	}
+
+	var locations []string
+	for _, s := range []string{geo.CountryName, geo.RegionName, geo.City} {
+		if strings.TrimSpace(s) != "" {
+			locations = append(locations, s)
+		}
+	}
+	location := strings.Join(locations, ", ")
+	if location == "" {
+		location = "Unknown"
+	}
+	country := geo.CountryName
+	if country == "" {
+		country = "Unknown"
+	}
+	gh := geohash.EncodeAuto(geo.Latitude, geo.Longitude)
+
+	return gh, country, location, nil
+}
+
+type ipapi struct {
+	Status      string  `json:"status"`
+	Message     string  `json:"message"`
+	Ip          string  `json:"query"`
+	CountryCode string  `json:"countryCode"`
+	CountryName string  `json:"country"`
+	RegionCode  string  `json:"region"`
+	RegionName  string  `json:"regionName"`
+	City        string  `json:"city"`
+	Zipcode     string  `json:"zip"`
+	Latitude    float64 `json:"lat"`
+	Longitude   float64 `json:"lon"`
+}
+
+func geohashAndLocationFromIpapi(address string) (string, string, string, error) {
+	var geo ipapi
+	response, err := http.Get("http://ip-api.com/json/" + address)
+	if err != nil {
+		return "s000", "Unknown", "Unknown", err
+	}
+	defer response.Body.Close()
+
+	body, err := ioutil.ReadAll(response.Body)
+	if err != nil {
+		return "s000", "Unknown", "Unknown", err
+	}
+
+	err = json.Unmarshal(body, &geo)
+	if err != nil {
+		return "s000", "Unknown", "Unknown", err
+	}
+
+	if geo.Status != "success" {
+		return "s000", "Unknown", "Unknown", fmt.Errorf("failed to query %v via ip-api: status: %v, message: %v", address, geo.Status, geo.Message)
+	}
+
+	var locations []string
+	for _, s := range []string{geo.CountryName, geo.RegionName, geo.City} {
+		if strings.TrimSpace(s) != "" {
+			locations = append(locations, s)
+		}
+	}
+	location := strings.Join(locations, ", ")
+	if location == "" {
+		location = "Unknown"
+	}
+	country := geo.CountryName
+	if country == "" {
+		country = "Unknown"
+	}
+	gh := geohash.EncodeAuto(geo.Latitude, geo.Longitude)
+
+	return gh, country, location, nil
+}
+
+func geohashAndLocation(address string, geoipSupplier string) (string, string, string, error) {
+	switch geoipSupplier {
+	case "off":
+		return "s000", "Geohash off", "Geohash off", nil
+	case "ip-api":
+		return geohashAndLocationFromIpapi(address)
+	case "freegeoip":
+		return geohashAndLocationFromFreegeoip(address)
+	default:
+		return "s000", "Unknown", "Unknown", fmt.Errorf("unknown geoipSupplier %v.", geoipSupplier)
+	}
+}

go.mod

@@ -1,3 +1,21 @@
 module endlessh-go
 
 go 1.17
+
+require (
+	github.com/golang/glog v1.0.0
+	github.com/pierrre/geohash v1.0.0
+	github.com/prometheus/client_golang v1.11.0
+)
+
+require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.1.1 // indirect
+	github.com/golang/protobuf v1.4.3 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
+	github.com/prometheus/client_model v0.2.0 // indirect
+	github.com/prometheus/common v0.26.0 // indirect
+	github.com/prometheus/procfs v0.6.0 // indirect
+	golang.org/x/sys v0.0.0-20210603081109-ebe580a85c40 // indirect
+	google.golang.org/protobuf v1.26.0-rc.1 // indirect
+)

go.sum

@@ -0,0 +1,156 @@
+cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+github.com/Codefor/geohash v0.0.0-20140723084247-1b41c28e3a9d h1:iG9B49Q218F/XxXNRM7k/vWf7MKmLIS8AcJV9cGN4nA=
+github.com/Codefor/geohash v0.0.0-20140723084247-1b41c28e3a9d/go.mod h1:RVnhzAX71far8Kc3TQeA0k/dcaEKUnTDSOyet/JCmGI=
+github.com/TomiHiltunen/geohash-golang v0.0.0-20150112065804-b3e4e625abfb h1:wumPkzt4zaxO4rHPBrjDK8iZMR41C1qs7njNqlacwQg=
+github.com/TomiHiltunen/geohash-golang v0.0.0-20150112065804-b3e4e625abfb/go.mod h1:QiYsIBRQEO+Z4Rz7GoI+dsHVneZNONvhczuA+llOZNM=
+github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
+github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
+github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
+github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
+github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
+github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
+github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
+github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
+github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
+github.com/broady/gogeohash v0.0.0-20120525094510-7b2c40d64042 h1:iEdmkrNMLXbM7ecffOAtZJQOQUTE4iMonxrb5opUgE4=
+github.com/broady/gogeohash v0.0.0-20120525094510-7b2c40d64042/go.mod h1:f1L9YvXvlt9JTa+A17trQjSMM6bV40f+tHjB+Pi+Fqk=
+github.com/cespare/xxhash/v2 v2.1.1 h1:6MnRN8NT7+YBpUIWxHtefFZOKTAPgGjpQSxqLNn0+qY=
+github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fanixk/geohash v0.0.0-20150324002647-c1f9b5fa157a h1:Fyfh/dsHFrC6nkX7H7+nFdTd1wROlX/FxEIWVpKYf1U=
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+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.5/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

main.go

@@ -1,68 +1,91 @@
 package main
 
-//  echo -n "test out the server" | nc localhost 3333
-
 import (
 	"flag"
 	"fmt"
 	"math/rand"
 	"net"
+	"net/http"
 	"os"
-	"sync/atomic"
 	"time"
+
+	"github.com/golang/glog"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 var (
-	numCurrentClients int64
+	numCurrentClients     int64
-	numTotalClients   uint64
+	numTotalClients       int64
-	numTotalBytes     uint64
+	numTotalClientsClosed int64
+	numTotalBytes         int64
+	numTotalMilliseconds  int64
+	totalClients          prometheus.CounterFunc
+	totalClientsClosed    prometheus.CounterFunc
+	totalBytes            prometheus.CounterFunc
+	totalSeconds          prometheus.CounterFunc
+	clientIP              *prometheus.CounterVec
+	clientSeconds         *prometheus.CounterVec
 )
 
-var letterBytes = []byte(" abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890!@#$%^&*()-=_+[]{}|;:',./<>?")
+func initPrometheus(connHost, prometheusPort, prometheusEntry string) {
-
+	totalClients = prometheus.NewCounterFunc(
-func randStringBytes(n int64) []byte {
+		prometheus.CounterOpts{
-	b := make([]byte, n+1)
+			Name: "endlessh_client_open_count_total",
-	for i := range b {
+			Help: "Total number of clients that tried to connect to this host.",
-		b[i] = letterBytes[rand.Intn(len(letterBytes))]
+		}, func() float64 {
-	}
+			return float64(numTotalClients)
-	b[n] = '\n'
+		},
-	return b
+	)
-}
+	totalClientsClosed = prometheus.NewCounterFunc(
-
+		prometheus.CounterOpts{
-type client struct {
+			Name: "endlessh_client_closed_count_total",
-	conn       net.Conn
+			Help: "Total number of clients that stopped connecting to this host.",
-	next       time.Time
+		}, func() float64 {
-	start      time.Time
+			return float64(numTotalClientsClosed)
-	bytes_sent int
+		},
-}
+	)
-
+	totalBytes = prometheus.NewCounterFunc(
-func NewClient(conn net.Conn, interval time.Duration, maxClient int64) *client {
+		prometheus.CounterOpts{
-	atomic.AddInt64(&numCurrentClients, 1)
+			Name: "endlessh_sent_bytes_total",
-	atomic.AddUint64(&numTotalClients, 1)
+			Help: "Total bytes sent to clients that tried to connect to this host.",
-	fmt.Printf("%v ACCEPT host=%v n=%v/%v\n", time.Now(), conn.RemoteAddr(), numCurrentClients, maxClient)
+		}, func() float64 {
-	return &client{
+			return float64(numTotalBytes)
-		conn:       conn,
+		},
-		next:       time.Now().Add(interval),
+	)
-		start:      time.Now(),
+	totalSeconds = prometheus.NewCounterFunc(
-		bytes_sent: 0,
+		prometheus.CounterOpts{
-	}
+			Name: "endlessh_trapped_time_seconds_total",
-}
+			Help: "Total seconds clients spent on endlessh.",
-
+		}, func() float64 {
-func (c *client) Send(bannerMaxLength int64) error {
+			return float64(numTotalMilliseconds) / 1000
-	length := rand.Int63n(bannerMaxLength)
+		},
-	bytes_sent, err := c.conn.Write(randStringBytes(length))
+	)
-	if err != nil {
+	clientIP = prometheus.NewCounterVec(
-		return err
+		prometheus.CounterOpts{
-	}
+			Name: "endlessh_client_open_count",
-	c.bytes_sent += bytes_sent
+			Help: "Number of connections of clients.",
-	atomic.AddUint64(&numTotalBytes, uint64(bytes_sent))
+		},
-	return nil
+		[]string{"ip", "geohash", "country", "location"},
-}
+	)
-
+	clientSeconds = prometheus.NewCounterVec(
-func (c *client) Close() {
+		prometheus.CounterOpts{
-	atomic.AddInt64(&numCurrentClients, -1)
+			Name: "endlessh_client_trapped_time_seconds",
-	fmt.Printf("%v CLOSE host=%v time=%v bytes=%v\n", time.Now(), c.conn.RemoteAddr(), time.Now().Sub(c.start), c.bytes_sent)
+			Help: "Seconds a client spends on endlessh.",
-	c.conn.Close()
+		},
+		[]string{"ip"},
+	)
+	prometheus.MustRegister(totalClients)
+	prometheus.MustRegister(totalClientsClosed)
+	prometheus.MustRegister(totalBytes)
+	prometheus.MustRegister(totalSeconds)
+	prometheus.MustRegister(clientIP)
+	prometheus.MustRegister(clientSeconds)
+	http.Handle("/"+prometheusEntry, promhttp.Handler())
+	go func() {
+		glog.Infof("Starting Prometheus on %v:%v, entry point is /%v", connHost, prometheusPort, prometheusEntry)
+		http.ListenAndServe(connHost+":"+prometheusPort, nil)
+	}()
 }
 
 func main() {
@@ -70,28 +93,40 @@ func main() {
 	bannerMaxLength := flag.Int64("line_length", 32, "Maximum banner line length")
 	maxClients := flag.Int64("max_clients", 4096, "Maximum number of clients")
 	connType := flag.String("conn_type", "tcp", "Connection type. Possible values are tcp, tcp4, tcp6")
-	connHost := flag.String("host", "localhost", "Listening address")
+	connHost := flag.String("host", "0.0.0.0", "Listening address")
 	connPort := flag.String("port", "2222", "Listening port")
+	enablePrometheus := flag.Bool("enable_prometheus", false, "Enable prometheus")
+	prometheusPort := flag.String("prometheus_port", "2112", "The port for prometheus")
+	prometheusEntry := flag.String("prometheus_entry", "metrics", "Entry point for prometheus")
+	geoipSupplier := flag.String("geoip_supplier", "ip-api", "Supplier to obtain Geohash of IPs. Possible values are \"ip-api\", \"freegeoip\"")
+
 	flag.Usage = func() {
 		fmt.Fprintf(flag.CommandLine.Output(), "Usage of %v \n", os.Args[0])
 		flag.PrintDefaults()
 	}
 	flag.Parse()
 
+	if *enablePrometheus {
+		initPrometheus(*connHost, *prometheusPort, *prometheusEntry)
+	}
+
 	rand.Seed(time.Now().UnixNano())
 	interval := time.Duration(*intervalMs) * time.Millisecond
 	// Listen for incoming connections.
+	if *connType == "tcp6" && *connHost == "0.0.0.0" {
+		*connHost = "[::]"
+	}
 	l, err := net.Listen(*connType, *connHost+":"+*connPort)
 	if err != nil {
-		fmt.Println("Error listening:", err.Error())
+		glog.Errorf("Error listening: %v", err)
 		os.Exit(1)
 	}
 	// Close the listener when the application closes.
 	defer l.Close()
-	fmt.Println("Listening on " + *connHost + ":" + *connPort)
+	glog.Infof("Listening on %v:%v", *connHost, *connPort)
 
 	clients := make(chan *client, *maxClients)
-	go func(clients chan *client, interval time.Duration, bannerMaxLength int64) {
+	go func() {
 		for {
 			c, more := <-clients
 			if !more {
@@ -100,26 +135,28 @@ func main() {
 			if time.Now().Before(c.next) {
 				time.Sleep(c.next.Sub(time.Now()))
 			}
-			err := c.Send(bannerMaxLength)
+			err := c.Send(*bannerMaxLength)
 			if err != nil {
 				c.Close()
 				continue
 			}
-			c.next = time.Now().Add(interval)
 			go func() { clients <- c }()
 		}
-	}(clients, interval, *bannerMaxLength)
+	}()
-	for {
+	listener := func() {
-		// Listen for an incoming connection.
+		for {
-		conn, err := l.Accept()
+			// Listen for an incoming connection.
-		if err != nil {
+			conn, err := l.Accept()
-			fmt.Println("Error accepting: ", err.Error())
+			if err != nil {
-			os.Exit(1)
+				glog.Errorf("Error accepting: %v", err)
+				os.Exit(1)
+			}
+			// Handle connections in a new goroutine.
+			for numCurrentClients >= *maxClients {
+				time.Sleep(interval)
+			}
+			clients <- NewClient(conn, interval, *maxClients, *geoipSupplier)
 		}
-		// Handle connections in a new goroutine.
-		for numCurrentClients >= *maxClients {
-			time.Sleep(interval)
-		}
-		clients <- NewClient(conn, interval, *maxClients)
 	}
+	listener()
 }