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Message-ID: <20230324153407.096d6248@kernel.org> Date: Fri, 24 Mar 2023 15:34:07 -0700 From: Jakub Kicinski <kuba@...nel.org> To: Aleksey Shumnik <ashumnik9@...il.com>, Thomas Winter <Thomas.Winter@...iedtelesis.co.nz> Cc: netdev@...r.kernel.org, davem@...emloft.net, dsahern@...nel.org, pabeni@...hat.com, edumazet@...gle.com, a@...table.cc Subject: Re: [BUG] gre interface incorrectly generates link-local addresses Adding Thomas as well. On Fri, 24 Mar 2023 19:35:06 +0300 Aleksey Shumnik wrote: > Dear Maintainers, > > I found that GRE arbitrarily hangs IP addresses from other interfaces > described in /etc/network/interfaces above itself (from bottom to > top). Moreover, this error occurs on both ip4gre and ip6gre. > > Example of mgre interface: > > 13: mgre1@...E: <MULTICAST,NOARP,UP,LOWER_UP> mtu 1400 qdisc noqueue > state UNKNOWN group default qlen 1000 > link/gre 0.0.0.0 brd 0.0.0.0 > inet 10.10.10.100/8 brd 10.255.255.255 scope global mgre1 > valid_lft forever preferred_lft forever > inet6 fe80::a0a:a64/64 scope link > valid_lft forever preferred_lft forever > inet6 fe80::7f00:1/64 scope host > valid_lft forever preferred_lft forever > inet6 fe80::a0:6842/64 scope host > valid_lft forever preferred_lft forever > inet6 fe80::c0a8:1264/64 scope host > valid_lft forever preferred_lft forever > > It seems that after the corrections in the following commits > https://github.com/torvalds/linux/commit/e5dd729460ca8d2da02028dbf264b65be8cd4b5f > https://github.com/torvalds/linux/commit/30e2291f61f93f7132c060190f8360df52644ec1 > https://github.com/torvalds/linux/commit/23ca0c2c93406bdb1150659e720bda1cec1fad04 > > in function add_v4_addrs() instead of stopping after this check: > > if (addr.s6_addr32[3]) { > add_addr(idev, &addr, plen, scope, IFAPROT_UNSPEC); > addrconf_prefix_route(&addr, plen, 0, idev->dev, 0, pflags, > GFP_KERNEL); > return; > } > > it goes further and in this cycle hangs addresses from all interfaces on the gre > > for_each_netdev(net, dev) { > struct in_device *in_dev = __in_dev_get_rtnl(dev); > if (in_dev && (dev->flags & IFF_UP)) { > struct in_ifaddr *ifa; > int flag = scope; > in_dev_for_each_ifa_rtnl(ifa, in_dev) { > addr.s6_addr32[3] = ifa->ifa_local; > if (ifa->ifa_scope == RT_SCOPE_LINK) > continue; > if (ifa->ifa_scope >= RT_SCOPE_HOST) { > if (idev->dev->flags&IFF_POINTOPOINT) > continue; > flag |= IFA_HOST; > } > add_addr(idev, &addr, plen, flag, > IFAPROT_UNSPEC); > addrconf_prefix_route(&addr, plen, 0, idev->dev, > 0, pflags, GFP_KERNEL); > } > } > > Moreover, before switching to Debian 12 kernel version 6.1.15, I used > Debian 11 on 5.10.140, and there was no error described in the commit > https://github.com/torvalds/linux/commit/e5dd729460ca8d2da02028dbf264b65be8cd4b5f. > One link-local address was always generated on the gre interface, > regardless of whether the destination or the local address of the > tunnel was specified. > > Which linux distribution did you use when you found an error with the > lack of link-local address generation on the gre interface? > After fixing the error, only one link-local address is generated? > I think this is a bug and most likely the problem is in generating > dev->dev_addr, since link-local is formed from it. > > I suggest solving this problem or roll back the code changes made in > the comments above.
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