From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: From: erik quanstrom Date: Mon, 21 Apr 2008 10:56:42 -0400 To: 9fans@9fans.net In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: Re: [9fans] telnet vs. godaddy whois Topicbox-Message-UUID: 963fc9e8-ead3-11e9-9d60-3106f5b1d025 On Thu Apr 17 19:07:09 EDT 2008, forsyth@terzarima.net wrote: > anyway, perhaps the more important question, at least for erik, is: will > his change cause trouble elsewhere? unfortunately, we don't know, but we'll > see how he gets along! > not setting the PSH bit when there's no data does fix the problem and has run for several days on some well-used machines without causing any issues with telnet, http, smtp, srv, cpu, import -E ssl &c. i would be surprised if the change caused any problem between plan 9 machines as the PSH bit may be set but is never tested. bwc points out that godaddy's behavior is very likely a violation of the rfc. while the PSH bit may be mistaken, compliant implementations are supposed to be liberal with what they accept. i can only assume that they are trying to defend against some sort of dos attack. perhaps someone has a better suggestion? it was suggested that the } was prehaps misplaced. i think this is not correct as the preceeding if modifieds dsize so i believe the ifs need to be seperate. /n/sources/plan9//sys/src/9/ip/tcp.c:2529,2535 - tcp.c:2529,2535 } } - if(sent+dsize == sndcnt) + if(sent+dsize == sndcnt && dsize) seg.flags |= PSH; /* keep track of balance of resent data */ - erik