Date: Tue, 17 Feb 2004 04:36:07 -0800 (PST) From: Alexander Motin <mav@alkar.net> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/62957: When created dummynet pipe on output router interface with lower MTU system stops to generate 'Fragment Needed but DF was Set' ICMP in cases when it must Message-ID: <200402171236.i1HCa7p2054112@www.freebsd.org> Resent-Message-ID: <200402171240.i1HCeKRU002449@freefall.freebsd.org>
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>Number: 62957 >Category: kern >Synopsis: When created dummynet pipe on output router interface with lower MTU system stops to generate 'Fragment Needed but DF was Set' ICMP in cases when it must >Confidential: no >Severity: serious >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Tue Feb 17 04:40:20 PST 2004 >Closed-Date: >Last-Modified: >Originator: Alexander Motin >Release: 4.8 and 5.2 >Organization: Alkar-Teleport ISP >Environment: FreeBSD ghsdr3-dp.alkar.net 4.8-RELEASE FreeBSD 4.8-RELEASE #2: Thu Oct 2 18:36:09 EEST 2003 povar@ghsdr3-dp.alkar.net:/usr/src/sys/compile/GHSDR2-DP i386 FreeBSD orphanage.alkar.net 5.2-RELEASE FreeBSD 5.2-RELEASE #0: Wed Jan 14 04:41:35 EET 2004 mav@orphanage.alkar.net:/usr/obj/usr/src/sys/orphanage i386 >Description: When I create dummynet pipe on output router interface with lower MTU system stops to generate 'Fragment Needed but DF was Set' ICMP in cases when it must. If I create this pipe on incoming interface there is no problem. >How-To-Repeat: Take router with 2 interfaces and small MTU on one of them. Create output dummynet pipe on interface with small MTU. Send big packet with DF flag set. >Fix: Check result code of ip_output() in ip_dummynet.c and send requires ICMP message. Here is no any check of result code: case DN_TO_IP_OUT: (void)ip_output((struct mbuf *)pkt, NULL, NULL, 0, NULL, NULL); rt_unref (pkt->ro.ro_rt, __func__) ; break ; >Release-Note: >Audit-Trail: >Unformatted:
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