Date: Thu, 31 May 2018 08:41:33 +0200 From: Andreas Nilsson <andrnils@gmail.com> To: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.cn85.dnsmgr.net> Cc: Dave Cottlehuber <dch@skunkwerks.at>, FreeBSD Net <freebsd-net@freebsd.org> Subject: Re: 'no route to host" for cloned lo1 iface 12.0-CURRENT r334376+56a973815425(master) amd64 Message-ID: <CAPS9%2BSsDE5TOQ4GvoBa2DMtX5GY72yx4-4XoTaSPOh%2BvO3mwcw@mail.gmail.com> In-Reply-To: <201805302211.w4UMBWTb073856@pdx.rh.CN85.dnsmgr.net> References: <1527716153.582028.1390935528.1D317B9B@webmail.messagingengine.com> <201805302211.w4UMBWTb073856@pdx.rh.CN85.dnsmgr.net>
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On Thu, May 31, 2018, 00:13 Rodney W. Grimes < freebsd-rwg@pdx.rh.cn85.dnsmgr.net> wrote: > > On Wed, 30 May 2018, at 17:46, Rodney W. Grimes wrote: > > > > > > > > ifconfig_lo1_aliases=3D"inet 10.241.0.0-15/16" > > > > > > > > > > lo1: flags=3D8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 m= tu > 16384 > > > > > > > > inet 10.241.0.0 netmask 0xffff0000 > > > > > > > > inet 10.241.0.1 netmask 0xffffffff > > > > > > > > inet 10.241.0.2 netmask 0xffffffff > > > > Thanks Rod, Andreas, Herbert for your help! Back at a proper computer > now. > > > > I think there are 2 things; invalid IP (see end for some interesting > notes), and also expansion of ifconfig_<if>_aliases. > > > > # ifconfig_$(if)_aliases > > > > This is my config: > > > > > cloned_interfaces=3D"lo1" > > > ifconfig_lo1_aliases=3D"inet 10.24 1.0.0-15/16" > I am not even sure that parses???? > > > > > But, I *don't* have a line like this: > > > > > ifconfig_lo1=3D"inet 10.241.0.0/16" > > This should be an error, or as per rfc treated as > "10.241.255.255/16" which should also be an error. > > > > > and if I add it and bump the range to 10.241.0.1/16, then all is well > again and ping $DODGY_IP works again, but I get 2 entries with /16 mask: > > > > inet 10.241.0.0 netmask 0xffff0000 > This should not be allowed. > > > inet 10.241.0.1 netmask 0xffff0000 > This is correct. > > > inet 10.241.0.2 netmask 0xffffffff > > > > So the solution seems to be this, to keep the 0xfff0000 to just 1 IP: > > > > > cloned_interfaces=3D"lo1" > > > ifconfig_lo1=3D"inet 10.241.0.0/16" > > > ifconfig_lo1_aliases=3D"inet 10.24 1.0.0-15/16" > How about cloned_interfaces=3D"lo1" ifconfig_lo1=3D"inet 10.241.0.0/16=E2=80=9D ifconfig_lo1_aliases=3D"10.241.0.1-15/32=E2=80=9D There is one other way, but I need to get to a computer to verify it. > > > Presumably I've copy-pasted this a long time ago and never questioned > it. I checked several random websites, and there are quite a few skipping > `ifconfig_lo1`, using just the aliases, and mainly with jail configs, so = I > guess this change will catch other people too. > > > > I'm not sure what's changed, as nothing recent in /etc/rc.d or > /etc/network.subr commits seems related. What's the best option here? > > > > Just a doc patch saying you can't use aliases without a prior > ifconfig_<if> ? > > I do not believe that needs to be a requirement. > > > > > # invalid IP > > > > TLDR 10.241.0.0/16 is technically not a valid host IP but it has > obviously worked in the past. > Yes, and that working in the past is bad, > probably need to see how far back this bug goes. > Eeekks.. it goes back to at least 5.4 which means > it is bad behavior we are probably going to have to fix. :-( > > > I've been binding 10.241.0.1-15 to jail IPs, and abusing 10.241.0.0 as > the "magic ip" that is bound to net/haproxy or spiped in the host system = to > broker exernal connections into the jail IP ranges from external internet= . > I will rectify my configuration but I will miss the symmetry :-) > > > > https://tools.ietf.org/html/rfc1122#section-3.3.6 is the closest > description I could find for this. Interestingly, they blame 4.2BSD for > this and say it's addressed since 4.3: > > > > ## 3.3.6 Broadcasts > ^^^^^^^^^^ > This is not the all 0's host value, but the all 1's host value, > these rules are VERY well known and enforced. I am actually > amazed that this use of 0 has not been RFC'ed out of existance, > as far as I know all the other stuff says that the 0th host > on a network is reserved for indicating the Network. > > If you look at all the tables on cidr and such they say > the valid host ranges are 1 to (END - 1) Leaving out > the host part value of 0. > Well, setting up point-to-point links for bgp and stuff it happens frequently that /31s are used to conserve ip space, which is sort of equivalent to having host ip of .0. > > > Section 3.2.1.3 defined the four standard IP broadcast address > > forms: > > Limited Broadcast: {-1, -1} > > Directed Broadcast: {<Network-number>,-1} > > Subnet Directed Broadcast: > > {<Network-number>,<Subnet-number>,-1} > > All-Subnets Directed Broadcast: {<Network-number>,-1,-1} > > A host MUST recognize any of these forms in the destination > > address of an incoming datagram. > > There is a class of hosts* that use non-standard broadcast > > address forms, substituting 0 for -1. All hosts SHOULD > ^^^^^^ > > recognize and accept any of these non-standard broadcast > ^^^^^^^^^^^ > > addresses as the destination address of an incoming datagram. > > Ok, so we *SHOULD* be mapping the 10.241.0.0 to 10.241.255.255 which > should of caused ALL the hosts on that subnet to respond to the ping. > > Someone want to investiage linux on this one? > > > _________________________ > > *4.2BSD Unix and its derivatives, but not 4.3BSD. > > -- > Rod Grimes > rgrimes@freebsd.org > _______________________________________________ > freebsd-net@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >
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