From owner-freebsd-net@FreeBSD.ORG Mon May 5 20:54:43 2008 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9CACB106564A for ; Mon, 5 May 2008 20:54:43 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from mail-out3.apple.com (mail-out3.apple.com [17.254.13.22]) by mx1.freebsd.org (Postfix) with ESMTP id 887A18FC19 for ; Mon, 5 May 2008 20:54:43 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from relay14.apple.com (relay14.apple.com [17.128.113.52]) by mail-out3.apple.com (Postfix) with ESMTP id 4CADA2AC361B; Mon, 5 May 2008 13:54:43 -0700 (PDT) Received: from relay14.apple.com (unknown [127.0.0.1]) by relay14.apple.com (Symantec Mail Security) with ESMTP id 2EA492808B; Mon, 5 May 2008 13:54:43 -0700 (PDT) X-AuditID: 11807134-a8ecdbb000000ed7-ac-481f741352ee Received: from cswiger1.apple.com (cswiger1.apple.com [17.214.13.96]) by relay14.apple.com (Apple SCV relay) with ESMTP id 095C52804C; Mon, 5 May 2008 13:54:43 -0700 (PDT) Message-Id: <2CE7D37B-CC67-4732-9562-6B2ED0857854@mac.com> From: Chuck Swiger To: hlwhyw@shtel.net.cn In-Reply-To: <424543f9f5.3f9f542454@shtel.net.cn> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v919.2) Date: Mon, 5 May 2008 13:54:42 -0700 References: <424543f9f5.3f9f542454@shtel.net.cn> X-Mailer: Apple Mail (2.919.2) X-Brightmail-Tracker: AAAAAA== Cc: freebsd-net@freebsd.org Subject: Re: Can I port 4.4BSD-Lite's TCP/IP protocol stack soure code to my own OS kernel which is GPL Licenced? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 May 2008 20:54:43 -0000 On May 4, 2008, at 6:32 AM, hlwhyw@shtel.net.cn wrote: > Can I port 4.4BSD-Lite's TCP/IP protocol stack soure code to my own > OS kernel which is GPL Licence? Modern 2- or 3-clause BSD licenses are fully compatible with the GPL, as are most "simple, permissive" licenses like the MIT/X11, Zlib, and similar licenses. The old 4-clause license with the "advertising clause" is not GPL-compatible. > I know that 4.4BSD-Lite is BSD Licenced. Is it legal to port BSD > Licenced code and change it to GPL licence? You are not allowed to remove the copyright statement or the original BSD license, but you can take BSD-licensed code and combine it with other software to create a derivative work which you then distribute under the GPL or even a proprietary license, if you wish. Eric Raymond and his wife, Catherine (who is a lawyer), have written some documentation about this specific issue here: http://catb.org/~esr/Licensing-HOWTO.html#id2787981 http://catb.org/~esr/Licensing-HOWTO.html#changing There was also a thread here: http://www.crynwr.com/cgi-bin/ezmlm-cgi?3:sss:15819:200804:ohmgonchmnecmnandlnk#b Regards, -- -Chuck