Date: Thu, 06 Oct 2011 15:16:02 +0400 From: "Alexander V. Chernikov" <melifaro@yandex-team.ru> To: Oleg Strizhak <oleg@pcbtech.ru> Cc: "Andrey V. Elsukov" <ae@FreeBSD.org>, melifaro@FreeBSD.org, freebsd-ipfw@FreeBSD.org Subject: Re: ipfw nat drops icmp packets from localhost Message-ID: <4E8D8DF2.8060309@yandex-team.ru> In-Reply-To: <4E8D860F.2030505@pcbtech.ru> References: <4E8D6702.9070707@pcbtech.ru> <4E8D7728.6050608@FreeBSD.org> <4E8D860F.2030505@pcbtech.ru>
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This is a multi-part message in MIME format. --------------020200020808050701040903 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit On 06.10.2011 14:42, Oleg Strizhak wrote: > Hello, Andrey V. Elsukov! > > You wrote on 06.10.2011 at 13:38: > >> On 06.10.2011 12:29, Oleg Strizhak wrote: >>> After an investigation I've found out a very strange situation - it >>> seems to me, that ipfw nat drops >>> some (type 11?) icmp reply packets, whose udp request packets it >>> hasn't rewritten/seen before, e.g: >>> >>> So, I wonder whether someone else has seen the same case under the >>> similar circumstances? Isn't it a >>> bug within ipfw nat module and is there any work-around/patch for >>> that? I've surely googled, but in >>> vain =( The only thing, that seems alike to my problem, is >>> http://www.freebsd.org/cgi/query-pr.cgi?pr=129093, but the patch for >>> 8 branch didn't cure anything =( >> >> Can you describe how you did apply and test this patch? > > in a usual way =) Unfortunately, copy-pasted from the mentioned above > page patch couldn't be applied w/ error: svn diff -c 223835 svn://svn.freebsd.org/base/stable/8 > ~/r223835.diff Can you try the patch attached (just to be sure) ? This is exact situation from this (and some related PRs) and this revision definitely fixes it. Btw, what is the value of net.inet.ip.fw.one_pass sysctl ? Are you sure that ipfw is the single enabled firewall on this machine ? Are you sure that system is using new kernel ? > >> $ patch < ~/ip_fw_nat.patch >> Hmm... Looks like a unified diff to me... >> The text leading up to this was: >> -------------------------- >> |--- stable/8/sys/netinet/ipfw/ip_fw_nat.c Thu Jul 7 08:33:58 >> 2011 (r223834) >> |+++ stable/8/sys/netinet/ipfw/ip_fw_nat.c Thu Jul 7 09:29:11 >> 2011 (r223835) >> -------------------------- >> Patching file ip_fw_nat.c using Plan A... >> patch: **** malformed patch at line 4: else > > the same results were obtained with combinations of -p5 -l and tail +2 > ~/ip_fw_nat.patch options & commands > Finally, I modified the patch (which applies w/o a word =) a little bit > w/o any difference to the original one: > >> $ /usr/bin/diff -wBbu3 ~/ip_fw_nat.patch ~/ip_fw_nat.patch.my >> --- /root/ip_fw_nat.patch 2011-10-04 14:08:32.000000000 +0400 >> +++ /root/ip_fw_nat.patch.my 2011-10-04 14:29:53.000000000 +0400 >> @@ -1,5 +1,5 @@ >> ---- stable/8/sys/netinet/ipfw/ip_fw_nat.c Thu Jul 7 08:33:58 >> 2011 (r223834) >> -+++ stable/8/sys/netinet/ipfw/ip_fw_nat.c Thu Jul 7 09:29:11 >> 2011 (r223835) >> +--- ip_fw_nat.c.orig 2010-12-21 20:09:25.000000000 +0300 >> ++++ ip_fw_nat.c 2011-10-04 14:27:02.000000000 +0400 >> @@ -263,17 +263,27 @@ >> else >> retval = LibAliasOut(t->lib, c, > > then I recompiled the kernel, rebooted server and.. all is just the same =( > > WBR, > Oleg > --------------020200020808050701040903 Content-Type: text/plain; name="r223835.diff" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="r223835.diff" Index: sys/netinet/ipfw/ip_fw_nat.c =================================================================== --- sys/netinet/ipfw/ip_fw_nat.c (revision 223834) +++ sys/netinet/ipfw/ip_fw_nat.c (revision 223835) @@ -263,17 +263,27 @@ else retval = LibAliasOut(t->lib, c, mcl->m_len + M_TRAILINGSPACE(mcl)); - if (retval == PKT_ALIAS_RESPOND) { - m->m_flags |= M_SKIP_FIREWALL; - retval = PKT_ALIAS_OK; - } - if (retval != PKT_ALIAS_OK && - retval != PKT_ALIAS_FOUND_HEADER_FRAGMENT) { + + /* + * We drop packet when: + * 1. libalias returns PKT_ALIAS_ERROR; + * 2. For incoming packets: + * a) for unresolved fragments; + * b) libalias returns PKT_ALIAS_IGNORED and + * PKT_ALIAS_DENY_INCOMING flag is set. + */ + if (retval == PKT_ALIAS_ERROR || + (args->oif == NULL && (retval == PKT_ALIAS_UNRESOLVED_FRAGMENT || + (retval == PKT_ALIAS_IGNORED && + (t->lib->packetAliasMode & PKT_ALIAS_DENY_INCOMING) != 0)))) { /* XXX - should i add some logging? */ m_free(mcl); args->m = NULL; return (IP_FW_DENY); } + + if (retval == PKT_ALIAS_RESPOND) + m->m_flags |= M_SKIP_FIREWALL; mcl->m_pkthdr.len = mcl->m_len = ntohs(ip->ip_len); /* Property changes on: sys/contrib/pf ___________________________________________________________________ Modified: svn:mergeinfo Merged /head/sys/contrib/pf:r222806 Property changes on: sys/contrib/dev/acpica ___________________________________________________________________ Modified: svn:mergeinfo Merged /head/sys/contrib/dev/acpica:r222806 Property changes on: sys/cddl/contrib/opensolaris ___________________________________________________________________ Modified: svn:mergeinfo Merged /head/sys/cddl/contrib/opensolaris:r222806 Property changes on: sys/amd64/include/xen ___________________________________________________________________ Modified: svn:mergeinfo Merged /head/sys/amd64/include/xen:r222806 Property changes on: sys ___________________________________________________________________ Modified: svn:mergeinfo Merged /head/sys:r222806 --------------020200020808050701040903--
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