netutils/netcat: Add netcat tool

Check readme for usage and demo:

[![weboftwins-osvehicle-2020-rzr](
https://files.mastodon.social/media_attachments/files/105/163/916/892/863/178/original/05468e28b4463f95.png
)](
https://mastodon.social/@rzr/105225153152922220#weboftwins-osvehicle-2020-rzr
"weboftwins-osvehicle-2020-rzr")

Change-Id: I2eac915954ca6cf585f01addb53df581631a7ae6
Bug: apache/nuttx#1999
Relate-to: rzr/aframe-smart-home#3
Origin: https://github.com/CrossStream/nuttx-apps/tree/sandbox/rzr/review/master/netutils/netcat
Forwarded: apache#482
Signed-off-by: Philippe Coval <rzr@users.sf.net>

netutils/netcat/Kconfig

@@ -0,0 +1,52 @@
+#############################################################################
+#
+# netutils/netcat/Kconfig
+# netcat networking application
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+#############################################################################
+
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config NETUTILS_NETCAT
+	bool "NetCat tool"
+	default n
+	select NET
+	select NET_TCP
+	---help---
+		Enable the NetCat TCP/IP swiss army tool
+
+if NETUTILS_NETCAT
+
+config NETUTILS_NETCAT_PROGNAME
+	string "Program name"
+	default "netcat"
+	---help---
+		This is the name of the program that will be use when the NSH ELF
+		program is installed.
+
+config NETUTILS_NETCAT_PRIORITY
+	int "netcat task priority"
+	default 100
+
+config NETUTILS_NETCAT_STACKSIZE
+	int "netcat stack size"
+	default DEFAULT_TASK_STACKSIZE
+
+endif

netutils/netcat/Make.defs

@@ -0,0 +1,25 @@
+#############################################################################
+#
+# netutils/netcat/Make.defs
+# netcat sample networking application
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+#############################################################################
+
+ifeq ($(CONFIG_NETUTILS_NETCAT),y)
+CONFIGURED_APPS += netutils/netcat
+endif

netutils/netcat/Makefile

@@ -0,0 +1,38 @@
+#############################################################################
+#
+# netutils/netcat/Makefile
+# Netcat networking application
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+#############################################################################
+
+include $(APPDIR)/Make.defs
+-include $(SDKDIR)/Make.defs
+
+# built-in application info
+
+PROGNAME = $(CONFIG_NETUTILS_NETCAT_PROGNAME)
+PRIORITY = $(CONFIG_NETUTILS_NETCAT_PRIORITY)
+STACKSIZE = $(CONFIG_NETUTILS_NETCAT_STACKSIZE)
+
+# Example
+
+ASRCS =
+CSRCS =
+MAINSRC = netcat_main.c
+
+include $(APPDIR)/Application.mk

netutils/netcat/README.md

@@ -0,0 +1,69 @@
+# Network Utilities / `netcat` tool
+
+netcat TCP/IP swiss army knife
+
+It was reimplemented from scratch for NuttX
+
+
+## DEMO ##
+
+[![weboftwins-osvehicle-2020-rzr](
+https://files.mastodon.social/media_attachments/files/105/163/916/892/863/178/original/05468e28b4463f95.png
+)](
+https://mastodon.social/@rzr/105225153152922220#weboftwins-osvehicle-2020-rzr
+"weboftwins-osvehicle-2020-rzr")
+
+  * https://purl.org/rzr/weboftwins
+
+## USAGE ##
+
+Usage is straigtforward:
+
+    nsh> help ; netcat
+    Usage: netcat [-l] [destination] [port] [file]
+
+    nsh> renew eth0 ; ifconfig
+
+    eth0    Link encap:Ethernet HWaddr 52:13:FF:FF:FF:FF at UP
+            inet addr:192.168.1.42 DRaddr:192.168.1.254 Mask:255.255.255.0
+
+In the following examples, following configuration is used:
+
+- target (nuttx) is 192.168.1.42
+- host (linux) is 192.168.1.55
+
+### Server ###
+
+As a server on NuttX and Linux's netcat as client
+
+    nsh> netcat -l
+
+    sh> cat /proc/version | netcat 192.168.1.42 31337
+    Linux ...
+
+Default port is 31337 but it can changed.
+
+    nsh> renew eth0 ; ifconfig ; netcat -l
+    log: net: listening on :31337
+    Linux ...
+
+### Client ###
+
+Start Server on GNU/Linux:
+
+    sh> ip addr show && netcat -l 31337
+
+Client side on nuttx, we create
+
+    nsh> help ; renew eth0 ; ifconfig
+    nsh> netcat 192.168.1.55 31337 /proc/version
+
+### Using pipes ###
+
+    mkfifo /dev/fifo
+    netcat 192.168.1.55 31337 /proc/fifo
+    help > /dev/fifo
+
+    fxos8700cq > /dev/fifo &
+    fxos8700cq [7:100]
+    netcat 192.168.1.55 31337  /dev/fifo