From mboxrd@z Thu Jan 1 00:00:00 1970 From: Friedrich Lobenstock Subject: Re: extra/pptp-conntrack-nat.patch Date: Fri, 11 Apr 2003 12:48:40 +0200 Sender: netfilter-devel-admin@lists.netfilter.org Message-ID: <3E969D88.4070005@fl.priv.at> References: Reply-To: netfilter-devel@lists.netfilter.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: Harald Welte Return-path: To: netfilter-devel@lists.netfilter.org In-Reply-To: Errors-To: netfilter-devel-admin@lists.netfilter.org List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Id: netfilter-devel.vger.kernel.org Jeff Hall wrote: > On Thu, 10 Apr 2003, Friedrich Lobenstock wrote: >> May I recall that I really have to remove the // to get it running. >> >> /* track caller id inside control connection, call expect_related */ >> static int >> conntrack_pptp_help(const struct iphdr *iph, size_t len, >> struct ip_conntrack *ct, enum ip_conntrack_info ctinfo) >> >> { ... >> >> /* checksum invalid? */ >> if (tcp_v4_check(tcph, tcplen, iph->saddr, iph->daddr, >> csum_partial((char *) tcph, tcplen, 0))) { >> printk(KERN_NOTICE __FILE__ ": bad csum\n"); >> // return NF_ACCEPT; >> } >> >> If I take a look at the cvs version of the patch there's a comment >> above the // line that says that w2k servers send out false csums. >> >> So do I understand this correct that if I remove the //, the pptp >> contrack module actually is more RFC conform than before? Or is >> it just the other way round? > > If you remove the comment and include the line "return NF_ACCEPT", then any > packet with an invalid checksum is NOT processed by the PPTP helper function. > With the line commented out the incorrect checksum is ignored and the packet > is processed by the rest of the PPTP helper function. Why this solved your > problem I can't say. I don't know either. Because of this I ask the author of this module to make this an option to the module, so I do not have to create two different versions of devil linux to support both possibilities. -- MfG / Regards Friedrich Lobenstock