Howdy all, I have been examining the licenses of the ‘lwipv6’ source package in Debian <URL:https://sources.debian.net/src/lwipv6/>.
Many of the files have copyright claimed by several copyright holders, and some of the copyright holders have applied different license conditions over time. By my understanding of copyright as the Debian project interprets the conventions, a work subject to several sets of license conditions is subject to the total set of restrictions. Prior license conditions do not cease to hold merely by applying a new license on top. The overall code base is distributed with copyright clamed (in <URL:https://sources.debian.net/src/lwipv6/1.5a-2/README.LICENSE/>) by: © 2004–2011 Renzo Davoli University of Bologna - Italy © 2001–2004 Swedish Institute of Computer Science When I inspect the copyright license conditions of, e.g., ‘chap.c’ <URL:https://sources.debian.net/src/lwipv6/1.5a-2/lwip-v6/src/netif/ppp/chap.c/> the declared copyright holders are: © 2003 Marc Boucher, Services Informatiques (MBSI) inc. © 1997 Global Election Systems Inc. © 1993 The Australian National University © 1991 Gregory M. Christy So by my reading, copyright in that file is under license conditions as set by *all* those copyright holders in that file, simultaneously. The specified license conditions are: * Gregory M. Christy grants license under equivalent of BSD 4-clause with advertising requirement. * The Australian National University grants license under equivalent of BSD 4-clause with advertising requirement. * Global Election Systems Inc., and Marc Boucher, Services Informatiques (MBSI) inc., both grant license under equivalent of BSD 2-clause. As for the overall code base: * Swedish Institute of Computer Science grants license under BSD 3-clause. * Renzo Davoli University of Bologna - Italy grants license under GNU GPL v2. The recipient only has license if all those license conditions can be satisfied, IIUC. So is a work under conditions of the BSD 4-clause license with its “obnoxious advertising clause”, or other license conditions with an equivalent clause, DFSG-free? I think the answer is no. Does this mean the ‘lwipv6’ work is non-free with the inclusion of files as per the example above? There are quite a few of them. Do those files need to be removed to make the work free? I don't know whether that's feasible. -- \ “… whoever claims any right that he is unwilling to accord to | `\ his fellow-men is dishonest and infamous.” —Robert G. | _o__) Ingersoll, _The Liberty of Man, Woman and Child_, 1877 | Ben Finney
