Mumps Compiler Server-Client Manual

This manual is meant to make the user familiar with the method used to compile and run mumps programs with the Mumps compiler which contact a server for their global data. It is fairly simple once the Mumps compiler package is compiled and running.

Running the server

First, you must choose which server you would like to run to make the global data accessible. You currently have three choices:

• UDP server - This server is the fastest of the three servers available, but is extremely error and crash prone in situations where network traffic is unreliable. It is also insecure, as all data is transferred in cleartext both ways. It is recommended for private LANs where there is little other traffic.
• TCP server - This server is slightly slower than the UDP server, but can overcome network errors which occur. It is recommended for Internet usage where it is not important if the data is intercepted in transmission. It provides no encryption of any kind and all data is sent and recieved in cleartext.
• SSL server - This server is the slowest of the three (a factor of 3 slower than TCP according to in-house tests). However, this server does provide moderate encryption. Data is encrypted using OpenSSL. Currently there is no authentication mechanism however. This server is recommended for data which you wish to be kept private in transmission. WARNING: Because this server provides no authentication, anyone who can connect to this server can retrieve any and all data stored in the global database. Future versions will incorporate a authentication method to counteract this.

Once you have chosen which server to run, you can run the server by executing it in a shell:

• UDP server - mumps-udp-server
• TCP server - mumps-tcp-server
• SSL server - mumps-ssl-server

The server is now running and ready for connections! If you need to stop the server at any time, send it a SIGINT. All servers also will output minimal information on client connections, and can optionally print out statistics on the amount of transactions at regular intervals.

Global data will persist through server runs, just as a local mumps program would. This allows you to switch between TCP, SSL and UDP servers while serving the same data.

Please note that while you can run both the UDP and TCP or UDP and SSL servers at the same time, the TCP and SSL server cannot ever be run at the same time, as SSL is run over TCP and they both use the same port number.

Compiling the client

To compile a Mumps program as a client to a server, use the -s option to mumpsc. This option takes one of three characters depending on which server type you will be connecting to:

• -sU - compiles a client to connect via UDP
• -sT - compiles a client to connect via TCP
• -sS - compiles a client to connect via SSL

Once a Mumps client is compiled, it will by default attempt to connect to localhost in order to contact the server. You can override this at any time by passing an option to the Mumps client as it is being run. For example: ./foo 192.168.9.1 would connect to the server running at 192.168.9.1. If a client will most likely be connecting to an IP that is different from localhost, you can change the default server by running mumpsc with the -d<IP> option. This will change the default server to <IP>.

The client should behave as a normal Mumps program would, as if it was accessing a local global database.

Special considerations for Mumps subfunctions

If for some reason you are compiling a subfunction from mumps to C and executing it from C only, you should place a call to the client_init() function at the beginning of the subfunction, and a client_close() at the end of the subfunction. These functions behave as follows:

• int client_init(char *host) - connect to host. Returns a 1 if successful, 0 otherwise.
• int client_close() - disconnect. Returns 1.

This document was written for the Mumps compiler by Michael Janssen. Any questions or comments can be sent to him at janssen@cns.uni.edu.