Re: bridge(4) and IPv6 broken?
- In reply to: Lexi Winter : "bridge(4) and IPv6 broken?"
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Date: Tue, 02 Jan 2024 07:51:34 UTC
Am 2024-01-02 00:40, schrieb Lexi Winter: > hello, > > i'm having an issue with bridge(4) and IPv6, with a configuration which > is essentially identical to a working system running releng/14.0. > > ifconfig: > > lo0: flags=1008049<UP,LOOPBACK,RUNNING,MULTICAST,LOWER_UP> metric 0 mtu > 16384 > options=680003<RXCSUM,TXCSUM,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6> > inet 127.0.0.1 netmask 0xff000000 > inet6 ::1 prefixlen 128 > inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 > groups: lo > nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL> > pflog0: flags=1000141<UP,RUNNING,PROMISC,LOWER_UP> metric 0 mtu 33152 > options=0 > groups: pflog > alc0: > flags=1008943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST,LOWER_UP> > metric 0 mtu 1500 > options=c3098<VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_MCAST,WOL_MAGIC,VLAN_HWTSO,LINKSTATE> > ether 30:9c:23:a8:89:a0 > inet6 fe80::329c:23ff:fea8:89a0%alc0 prefixlen 64 scopeid 0x3 > media: Ethernet autoselect (1000baseT <full-duplex>) > status: active > nd6 options=1<PERFORMNUD> > wg0: flags=10080c1<UP,RUNNING,NOARP,MULTICAST,LOWER_UP> metric 0 mtu > 1420 > options=80000<LINKSTATE> > inet 172.16.145.21 netmask 0xffffffff > inet6 fd00:0:1337:cafe:1111:1111:829a:595e prefixlen 128 > groups: wg > tunnelfib: 1 > nd6 options=101<PERFORMNUD,NO_DAD> > bridge0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> > metric 0 mtu 1500 > options=0 > ether 58:9c:fc:10:ff:b6 > inet 10.1.4.101 netmask 0xffffff00 broadcast 10.1.4.255 > inet6 2001:8b0:aab5:104:3::101 prefixlen 64 > id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15 > maxage 20 holdcnt 6 proto rstp maxaddr 2000 timeout 1200 > root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0 > member: tap0 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP> > ifmaxaddr 0 port 6 priority 128 path cost 2000000 > member: alc0 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP> > ifmaxaddr 0 port 3 priority 128 path cost 55 > groups: bridge > nd6 options=1<PERFORMNUD> > tap0: flags=9903<UP,BROADCAST,PROMISC,SIMPLEX,LINK0,MULTICAST> metric 0 > mtu 1500 > options=80000<LINKSTATE> > ether 58:9c:fc:10:ff:89 > groups: tap > media: Ethernet 1000baseT <full-duplex> > status: no carrier > nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> > > the issue is that the bridge doesn't seem to respond to IPv6 ICMP > Neighbour Solicitation. for example, while running ping, tcpdump shows > this: > > 23:30:16.567071 58:9c:fc:10:ff:b6 > 1e:ab:48:c1:f6:62, ethertype IPv6 > (0x86dd), length 70: 2001:8b0:aab5:104:3::101 > 2001:8b0:aab5:106::12: > ICMP6, echo request, id 34603, seq 13, length 16 > 23:30:16.634860 1e:ab:48:c1:f6:62 > 33:33:ff:00:01:01, ethertype IPv6 > (0x86dd), length 86: fe80::1cab:48ff:fec1:f662 > ff02::1:ff00:101: > ICMP6, neighbor solicitation, who has 2001:8b0:aab5:104:3::101, length > 32 > 23:30:17.567080 58:9c:fc:10:ff:b6 > 1e:ab:48:c1:f6:62, ethertype IPv6 > (0x86dd), length 70: 2001:8b0:aab5:104:3::101 > 2001:8b0:aab5:106::12: > ICMP6, echo request, id 34603, seq 14, length 16 > 23:30:17.674842 1e:ab:48:c1:f6:62 > 33:33:ff:00:01:01, ethertype IPv6 > (0x86dd), length 86: fe80::1cab:48ff:fec1:f662 > ff02::1:ff00:101: > ICMP6, neighbor solicitation, who has 2001:8b0:aab5:104:3::101, length > 32 > 23:30:17.936956 1e:ab:48:c1:f6:62 > 33:33:00:00:00:01, ethertype IPv6 > (0x86dd), length 166: fe80::1cab:48ff:fec1:f662 > ff02::1: ICMP6, > router advertisement, length 112 > 23:30:18.567093 58:9c:fc:10:ff:b6 > 1e:ab:48:c1:f6:62, ethertype IPv6 > (0x86dd), length 70: 2001:8b0:aab5:104:3::101 > 2001:8b0:aab5:106::12: > ICMP6, echo request, id 34603, seq 15, length 16 > 23:30:19.567104 58:9c:fc:10:ff:b6 > 1e:ab:48:c1:f6:62, ethertype IPv6 > (0x86dd), length 70: 2001:8b0:aab5:104:3::101 > 2001:8b0:aab5:106::12: > ICMP6, echo request, id 34603, seq 16, length 16 > 23:30:19.567529 1e:ab:48:c1:f6:62 > 33:33:ff:00:01:01, ethertype IPv6 > (0x86dd), length 86: fe80::1cab:48ff:fec1:f662 > ff02::1:ff00:101: > ICMP6, neighbor solicitation, who has 2001:8b0:aab5:104:3::101, length > 32 > > fe80::1cab:48ff:fec1:f662 is the subnet router; it's sending > solicitations but FreeBSD doesn't send a response, > > if i remove alc0 from the bridge and configure the IPv6 address > directly > on alc0 instead, everything works fine. > > i'm testing without any packet filter (ipfw/pf) in the kernel. > > it's possible i'm missing something obvious here; does anyone have an > idea? Just an idea. I'm not sure if it is the right track... There is code in the kernel which is ignoring NS stuff from "non-valid" sources (security / spoofing reasons). The NS request is from a link local address. Your bridge has no link local address (and your tap has the auto linklocal flag set which I would have expected to be on the bridge instead). I'm not sure but I would guess it could be because of this. If my guess is not too far off, I would suggest to try: - remove auto linklocal from tap0 (like for alc0) - add auto linklocal to bridge0 If this doesn't help, there is the sysctl net.inet6.icmp6.nd6_onlink_ns_rfc4861 which you could try to set to 1. Please read https://www.freebsd.org/security/advisories/FreeBSD-SA-08:10.nd6.asc before you do that. Bye, Alexander. -- http://www.Leidinger.net Alexander@Leidinger.net: PGP 0x8F31830F9F2772BF http://www.FreeBSD.org netchild@FreeBSD.org : PGP 0x8F31830F9F2772BF