Network Utilities

Contents

• uIP Applications
• Other Network Applications
• Tips for Using Telnetd
• Tips for Using DHCPC

uIP Applications

This directory contains most of the network applications contained under the uIP-1.0 apps directory. As the uIP apps/README.md says, these applications are not all heavily tested. These uIP-based apps include:

• dhcpc – Dynamic Host Configuration Protocol (DHCP) client. See apps/include/netutils/dhcpc.h for interface information.

• smtp – Simple Mail Transfer Protocol (SMTP) client. See apps/include/netutils/smtp.h for interface information.

• webclient – HTTP web client. See apps/include/netutils/webclient.h for interface information.

• webserver – HTTP web server. See apps/include/netutils/httpd.h for interface information.

You may find additional information on these apps in the uIP forum accessible through: http://www.sics.se/~adam/uip/index.php/Main_Page. Some of these (such as the uIP web server) have grown some additional functionality due primarily to NuttX user contributions.

Other Network Applications

Additional applications that were not part of uIP (but which are highly influenced by uIP) include:

• dhcpd – Dynamic Host Configuration Protocol (DHCP) server. See apps/include/netutils/dhcpd.h for interface information.

• discover – This daemon is useful for discovering devices in local networks, especially with DHCP configured devices. It listens for UDP broadcasts which also can include a device class so that groups of devices can be discovered. It is also possible to address all classes with a kind of broadcast discover. (Contributed by Max Holtzberg).

• esp8266 – An ESP8266 networking layer contributed by Pierre-Noel Bouteville.

• json – cJSON is an ultra-lightweight, portable, single-file, simple-as-can-be ANSI-C compliant JSON parser, under MIT license. Embeddable Lightweight XML-RPC Server discussed at http://www.drdobbs.com/web-development/an-embeddable-lightweight-xml-rpc-server/184405364.

This code was taken from http://sourceforge.net/projects/cjson/ and adapted for NuttX by Darcy Gong.

• tftpc – TFTP client. See apps/include/netutils/tftp.h for interface information.

• telnetc – This is a port of libtelnet to NuttX. This is a public domain Telnet client library available from https://github.com/seanmiddleditch/libtelnet modified for use with NuttX. Original Authors: Sean Middleditch sean@sourcemud.org, Jack Kelly endgame.dos@gmail.com and Katherine Flavel kate@elide.org

• telnetd – TELNET server. This is the Telnet logic adapted from uIP and generalized for use as the front end to any shell. The telnet daemon creates sessions that are wrapped as character devices and mapped to stdin, stdout and stderr. Now the telnet session can be inherited by spawned tasks.

• ftpc – FTP client. See apps/include/netutils/ftpc.h for interface information.

• ftpd – FTP server. See apps/include/netutils/ftpd.h for interface information.

• ntpclient – This is a fragmentary NTP client. It neither well-tested nor mature nor complete at this point in time.

• thttpd – This is a port of Jef Poskanzer's THTTPD HTPPD server. See http://acme.com/software/thttpd/ for general THTTPD information. See apps/include/netutils/thttpd.h for interface information. Applications using this thttpd will need to provide the following definitions in the defconfig file to select the appropriate netutils libraries:

  CONFIG_NETUTILS_NETLIB=y
  CONFIG_NETUTILS_THTTPD=y

• xmlrpc – The Embeddable Lightweight XML-RPC Server discussed at http://www.drdobbs.com/web-development/an-embeddable-lightweight-xml-rpc-server/184405364

• ping – This is an unfinished implementation of ping and ping6 using raw sockets. It is not yet hooked into the configuration or build systems.

Current ping/ping6 logic in NSH makes illegal calls into the OS in order to implement ping/ping6. One correct implementation would be to use raw sockets to implement ping/ping6 as a user application. This is a first cut at such an implementation.

Tips for Using Telnetd

Telnetd is set up to be the front end for a shell. The primary use of Telnetd in NuttX is to support the NuttShell (NSH) Telnet front end. See apps/include/netutils/telnetd.h for information about how to incorporate Telnetd into your custom applications.

To enable and link the Telnetd daemon, you need to include the following in in your defconfig file:

CONFIG_NETUTILS_NETLIB=y
CONFIG_NETUTILS_TELNETD=y

Also if the Telnet console is enabled, make sure that you have the following set in the NuttX configuration file or else the performance will be very bad (because there will be only one character per TCP transfer):

• CONFIG_STDIO_BUFFER_SIZE – Some value >= 64.
• CONFIG_STDIO_LINEBUFFER=y – Since Telnetd is line oriented, line buffering is optimal.

Tips for Using DHCPC

If you use DHCPC/D, then some special configuration network options are required. These include:

• CONFIG_NET=y
• CONFIG_NET_UDP=y – UDP support is required for DHCP (as well as various other UDP-related configuration settings).
• CONFIG_NET_BROADCAST=y – UDP broadcast support is needed.
• CONFIG_NET_ETH_PKTSIZE=650 or larger. The client must be prepared to receive DHCP messages of up to 576 bytes (excluding Ethernet, IP or UDP headers and FCS). Note: Note that the actual MTU setting will depend upon the specific link protocol. Here Ethernet is indicated.