FEAT: simple TCP port scanner (module)

related to: Oldes/Rebol-issues#1422

src/modules/port-scanner.reb

@@ -0,0 +1,100 @@
+Rebol [
+ Title: "TCP Port scanner"
+ File: %port-scanner.reb
+ Type: module
+ Name: port-scanner
+ Version: 1.0.0
+ Date: 16-Feb-2021
+ Exports: [scan-ports]
+ Note: {
+ If you use anything other than `localhost` you had better have permission
+ for the host name you do use, or you will suddenly be an *internet bad guy*.
+ Don't.}
+]
+
+; result:
+found: copy []
+
+; options:
+batch-size: 8000 ; higher batch size means higher CPU use!
+timeout: 0:0:0.5 ; setting timeout too low may result in not resolved opened ports!
+
+; actor:
+on-awake: func [event /local port id] [
+ port: event/port
+ ;print [as-green "==TCP-event:" as-red event/type "port:" as-red port/spec/port-id]
+ switch/default event/type [
+ lookup [open port]
+ connect [
+ id: port/spec/port-id
+ print ["Open port found:" as-red id]
+ append found id
+ false
+ ]
+ ][true]
+]
+
+scan-ports: function [
+ from [integer!] "lowest port numer"
+ to [integer!] "max port number"
+ /host name [tuple! string!]
+][
+ clear found
+ checking: make block! batch-size
+ started: now/time/precise
+
+ if to < from [id: to to: from from: id]
+
+ id: low: 
+ from: max 1 from
+ to: max 1 min to 65535
+
+ total: 1 + to - from
+
+ try/except [
+ ip: either tuple? name [ name ][
+ read join dns:// any [name 'localhost]
+ ]
+ ][
+ sys/log/error 'REBOL system/state/last-error
+ return none
+ ]
+
+ print [
+ as-green "Using IP:" as-yellow ip
+ as-green "timeout:" as-yellow timeout
+ as-green "batch size:" as-yellow batch-size
+ newline
+ ]
+
+ while [id <= to][
+ port: make port! compose [
+ scheme: 'tcp
+ host: (ip)
+ port-id: (id)
+ awake: :on-awake
+ ]
+ open port
+ append checking port
+ if any [
+ id = to
+ batch-size = length? checking
+ ][
+ print [as-green "Checking range:" as-yellow low "-" as-yellow id]
+ ; wait some time...
+ wait timeout
+ ; and check what was opened...
+ foreach port checking [ close port ]
+ clear checking
+ if id < to [ low: low + batch-size ]
+ ]
+ ++ id
+ ]
+ checking: none
+ print ajoin [
+ as-green "^/Scan of " as-yellow total
+ as-green " ports finished in time: " as-yellow now/time/precise - started
+ as-green ".^/Found " as-red length? found as-green " listening TCP ports!^/"
+ ]
+ found
+]

src/tests/test-port-scanner.r3

@@ -0,0 +1,21 @@
+Rebol [
+ Title: "Test async TCP port scanner"
+ File: %test-port-scanner.r3
+ Date: 16-Feb-2021
+]
+
+scanner: import 'port-scanner
+
+;- higher batch size means higher CPU use!
+;scanner/batch-size: 10000
+;- low timeout may result in not founding all listening ports!
+;- if the scenner is used on non local ip, the timeout should
+;- count with netword latency!
+;scanner/timeout: 0:0:0.25
+
+scan-ports/host 1 65535 127.0.0.1
+
+if system/options/script [
+ ?? scanner/found
+ ask "^/DONE"
+]