Date: Thu, 13 Sep 2012 12:01:56 -0500 From: Soren Dreijer <dreijer+bsd@echobit.net> To: Luigi Rizzo <rizzo@iet.unipi.it> Cc: freebsd-ipfw@freebsd.org, Ian Smith <smithi@nimnet.asn.au> Subject: Re: Significant network latency when using ipfw and in-kernel NAT Message-ID: <CALoZf3iRzx5V=1th32LE8OCa0_GTBNGSZeGuH9qTp4Fk1j3ZRw@mail.gmail.com> In-Reply-To: <20120913163013.GA22049@onelab2.iet.unipi.it> References: <CALoZf3hfZDQQ4ZEXMrGUkYiGvb5QPoAcbpUikAq1adqVY4fLyg@mail.gmail.com> <20120913221758.E51539@sola.nimnet.asn.au> <CALoZf3iCf1_fHgAWUXa3fgudOe66sbk35P0CYhgsneBuhCORJg@mail.gmail.com> <20120913163013.GA22049@onelab2.iet.unipi.it>
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Luigi and Ian, As Ian mentioned, we had some off-list discussion by accident and he suggested the TSO approach too (although I don't know how that would affect e.g. ICMP traffic). It seems to have been a known issue for a while (http://lists.freebsd.org/pipermail/freebsd-net/2010-July/025743.html). Does anybody know if this is still the case in 9-0-RELEASE? I've already done "ifconfig ix1 -tso" to disable TSO on the public nic, but there was no difference. I'm not sure what VLAN_HWTSO means, though. Is the nic doing TSO on its own? Do I need to turn that off as well?. also, do I need to turn off TSO on ix0, which is what the ip tunnel runs over? Thanks, Soren On Thu, Sep 13, 2012 at 11:30 AM, Luigi Rizzo <rizzo@iet.unipi.it> wrote: > > [top posting for readability] > i have seen this kind of issues related to bad interaction > between the nat code and the various accelerations > (mostly TSO/RSC, but i would also try to disable the > checksums). > Try to remove tso,csum, possibly rsc if you have it, and see > if the problem continues. Please post the result so people > reading this thread in the future can tell whether my suggestion > was useful or not. > > cheers > luigi > > > On Thu, Sep 13, 2012 at 10:48:01AM -0500, Soren Dreijer wrote: >> Definitely. Since this is a server in production, I've obfuscated some >> of the IPs, etc. >> >> First off, here's the ifconfig. Our setup consists of a private (ix0) >> and a public nic (ix1) and an ip tunnel (gif0), which is what we use >> in ipfw to forward incoming packets to our internal boxes: >> >> ix0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 >> options=401bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO> >> ether XX:XX:XX:XX:XX:XX >> inet <private VLAN IP> netmask 0xffffffc0 broadcast xx >> inet6 xxxx::xxx:xxxx:xxxx:xxxx%ix0 prefixlen 64 scopeid 0x7 >> nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> >> media: Ethernet autoselect (10Gbase-Twinax <full-duplex>) >> status: active >> ix1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 >> options=400bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,VLAN_HWTSO> >> ether XX:XX:XX:XX:XX:XX >> inet <public IP> netmask 0xfffffff8 broadcast xx >> inet6 xxxx::xxx:xxxx:xxxx:xxxx%ix1 prefixlen 64 scopeid 0x8 >> inet <alias public IP> netmask 0xffffffff broadcast xx >> inet <alias public IP> netmask 0xffffffff broadcast xx >> nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> >> media: Ethernet autoselect (10Gbase-Twinax <full-duplex>) >> status: active >> ipfw0: flags=8801<UP,SIMPLEX,MULTICAST> metric 0 mtu 65536 >> nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> >> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384 >> options=3<RXCSUM,TXCSUM> >> inet6 ::1 prefixlen 128 >> inet6 fe80::1%lo0 prefixlen 64 scopeid 0xa >> inet 127.0.0.1 netmask 0xff000000 >> nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL> >> gif0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> metric 0 mtu 1500 >> tunnel inet <private VLAN IP> --> <private VLAN IP> >> inet 172.16.1.1 --> 172.16.1.2 netmask 0xffff0000 >> nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> >> options=1<ACCEPT_REV_ETHIP_VER> >> >> The basic ruleset looks like this. One-pass is off so that packets are >> reinjected after going through NAT'ing and pipes: >> >> 00001 16653 4417407 allow ip from any to any via ix0 >> 00003 14588 2860344 allow ip from any to any via gif1 >> 00006 0 0 allow ip from any to any via lo0 >> 00010 0 0 deny ip from 192.168.0.0/16 to any in via ix1 >> 00011 0 0 deny ip from 172.16.0.0/12 to any in via ix1 >> 00012 0 0 deny ip from 10.0.0.0/8 to any in via ix1 >> 00013 0 0 deny ip from 127.0.0.0/8 to any in via ix1 >> 00014 0 0 deny ip from 0.0.0.0/8 to any in via ix1 >> 00015 0 0 deny ip from 169.254.0.0/16 to any in via ix1 >> 00016 0 0 deny ip from 192.0.2.0/24 to any in via ix1 >> 00017 0 0 deny ip from 204.152.64.0/23 to any in via ix1 >> 00018 0 0 deny ip from 224.0.0.0/3 to any in via ix1 >> 00019 15 1020 allow icmp from any to any via ix1 # For >> testing purposes, allow all ICMP in and out of the public adapter >> 00020 7537 647951 nat 1 ip from any to any in via ix1 # NAT all >> incoming traffic >> 00030 0 0 check-state # For some reason, this never gets >> matched even though rule #100 is matched >> 00100 161 124340 skipto 805 tcp from any to any out via ix1 >> setup keep-state # For testing purposes, allow all TCP originating >> from the box out of the public adapter >> 00110 0 0 skipto 805 icmp from any to any out via ix1 keep-state >> 00200 36557 1996626 skipto 500 tcp from any to 172.16.1.2 dst-port >> 443 in via ix1 # Forward NAT'ed traffic for port 443 over the ip >> tunnel >> 00201 46593 63973143 skipto 805 tcp from 172.16.1.2 443 to any out via ix1 >> 00400 8 6192 deny ip from any to any via ix1 >> 00500 0 0 pipe 1 ip from any to any in via ix1 # Packet shaping >> 00501 0 0 allow ip from any to any in via ix1 >> 00805 8963 3412995 nat 1 ip from any to any out via ix1 >> 00806 8963 3412995 allow ip from any to any >> 10000 0 0 deny ip from any to any via ix1 # Last ditch catch >> 65535 864357 867120912 allow ip from any to any >> >> 'ipfw nat show config' yields: >> >> ipfw nat 1 config if ix1 log reset redirect_port tcp 172.16.1.2:443 >> <public IP>:443 >> >> And finally, here are the horrifying ping times (furthermore, all >> outgoing TCP traffic originating from this box, such as wget or >> pkg_add, time out. I've managed to get an outgoing telnet working, but >> it's horrible slow and takes a while to establish): >> >> PING google.com (74.125.227.14): 56 data bytes >> 64 bytes from 74.125.227.14: icmp_seq=0 ttl=56 time=2746.953 ms >> 64 bytes from 74.125.227.14: icmp_seq=1 ttl=56 time=2097.460 ms >> 64 bytes from 74.125.227.14: icmp_seq=2 ttl=56 time=2186.068 ms >> 64 bytes from 74.125.227.14: icmp_seq=3 ttl=56 time=4292.776 ms >> 64 bytes from 74.125.227.14: icmp_seq=4 ttl=56 time=5056.965 ms >> 64 bytes from 74.125.227.14: icmp_seq=5 ttl=56 time=5323.720 ms >> 64 bytes from 74.125.227.14: icmp_seq=6 ttl=56 time=5007.974 ms >> 64 bytes from 74.125.227.14: icmp_seq=7 ttl=56 time=4756.587 ms >> >> It's worth mentioning that when I switch back to using natd and divert >> in the ruleset (which really only changes the nat portions and >> everything else stays the same), the ping time drops to ~300ms, which >> is a big difference for simply "using" natd even when the ICMP packets >> aren't supposed to be going through NAT'ing whatsoever. The ~300ms >> ping time is still way too high, though, since our other boxes have a >> ping time to Google of ~0.300ms... >> >> Any ideas? >> >> On Thu, Sep 13, 2012 at 7:41 AM, Ian Smith <smithi@nimnet.asn.au> wrote: >> > On Wed, 12 Sep 2012 23:09:27 -0500, Soren Dreijer wrote: >> > > Hi there, >> > > >> > > We're running freebsd 9.0-RELEASE on a box whose primary purpose is to >> > > act as a firewall and a gateway. Up until today, we've been using ipfw >> > > in conjunction with natd and the divert action in ipfw to forward >> > > packets between the freebsd box (i.e. the public Internet) and our >> > > private servers. >> > > >> > > Unfortunately, natd appears to be quite the CPU hog and we therefore >> > > decided to switch to the in-kernel NAT support in ipfw. The issue >> > > we're running in to is that the network latency appears to be >> > > skyrocketing when ipfw contains nat rules. Basically all TCP traffic >> > > originating from the box times out and pinging google.com on the box >> > > gives an average of ~10 SECONDS -- and that's even if I explicitly >> > > allow all ICMP traffic before the packets even get to the nat rules in >> > > ipfw. >> > > >> > > The really odd part, however, is that I can ping the freebsd box just >> > > fine externally. For instance, pinging the server from my home >> > > connection gives an average of 45 ms. I'm also able to communicate >> > > just fine with the internal servers through the freebsd box. >> > > >> > > Does anybody have any idea what's going on? I assume I must've >> > > misconfigured something big here... >> > >> > Or maybe only something small .. but without seeing your basic ruleset >> > and network config - obscured as need be - we can only guess. Maybe an >> > 'ifconfig', 'ipfw show' and 'ipfw nat show config' would illustrate? >> > >> > cheers, Ian >> _______________________________________________ >> freebsd-ipfw@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-ipfw >> To unsubscribe, send any mail to "freebsd-ipfw-unsubscribe@freebsd.org"
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