diff options
author | Daniel Borkmann <daniel@iogearbox.net> | 2021-10-11 14:12:36 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-11-17 09:48:49 +0100 |
commit | aba12bb38b10039917bc23ae487bd7a4e76a7015 (patch) | |
tree | 45f2ed06d3553224243dc72bec34066f9acc97bb /net/core | |
parent | 223985fa1b5f45d72ce1b5c5859702ca02fd8433 (diff) |
net, neigh: Enable state migration between NUD_PERMANENT and NTF_USE
[ Upstream commit 3dc20f4762c62d3b3f0940644881ed818aa7b2f5 ]
Currently, it is not possible to migrate a neighbor entry between NUD_PERMANENT
state and NTF_USE flag with a dynamic NUD state from a user space control plane.
Similarly, it is not possible to add/remove NTF_EXT_LEARNED flag from an existing
neighbor entry in combination with NTF_USE flag.
This is due to the latter directly calling into neigh_event_send() without any
meta data updates as happening in __neigh_update(). Thus, to enable this use
case, extend the latter with a NEIGH_UPDATE_F_USE flag where we break the
NUD_PERMANENT state in particular so that a latter neigh_event_send() is able
to re-resolve a neighbor entry.
Before fix, NUD_PERMANENT -> NUD_* & NTF_USE:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT
[...]
As can be seen, despite the admin-triggered replace, the entry remains in the
NUD_PERMANENT state.
After fix, NUD_PERMANENT -> NUD_* & NTF_USE:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn REACHABLE
[...]
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn STALE
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT
[...]
After the fix, the admin-triggered replace switches to a dynamic state from
the NTF_USE flag which triggered a new neighbor resolution. Likewise, we can
transition back from there, if needed, into NUD_PERMANENT.
Similar before/after behavior can be observed for below transitions:
Before fix, NTF_USE -> NTF_USE | NTF_EXT_LEARNED -> NTF_USE:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE
[...]
After fix, NTF_USE -> NTF_USE | NTF_EXT_LEARNED -> NTF_USE:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn REACHABLE
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE
[..]
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Roopa Prabhu <roopa@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/core')
-rw-r--r-- | net/core/neighbour.c | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 3a4cf53e3841..02e55041a881 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1221,7 +1221,7 @@ static void neigh_update_hhs(struct neighbour *neigh) lladdr instead of overriding it if it is different. NEIGH_UPDATE_F_ADMIN means that the change is administrative. - + NEIGH_UPDATE_F_USE means that the entry is user triggered. NEIGH_UPDATE_F_OVERRIDE_ISROUTER allows to override existing NTF_ROUTER flag. NEIGH_UPDATE_F_ISROUTER indicates if the neighbour is known as @@ -1259,6 +1259,12 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr, goto out; ext_learn_change = neigh_update_ext_learned(neigh, flags, ¬ify); + if (flags & NEIGH_UPDATE_F_USE) { + new = old & ~NUD_PERMANENT; + neigh->nud_state = new; + err = 0; + goto out; + } if (!(new & NUD_VALID)) { neigh_del_timer(neigh); @@ -1966,22 +1972,20 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh, if (protocol) neigh->protocol = protocol; - if (ndm->ndm_flags & NTF_EXT_LEARNED) flags |= NEIGH_UPDATE_F_EXT_LEARNED; - if (ndm->ndm_flags & NTF_ROUTER) flags |= NEIGH_UPDATE_F_ISROUTER; + if (ndm->ndm_flags & NTF_USE) + flags |= NEIGH_UPDATE_F_USE; - if (ndm->ndm_flags & NTF_USE) { + err = __neigh_update(neigh, lladdr, ndm->ndm_state, flags, + NETLINK_CB(skb).portid, extack); + if (!err && ndm->ndm_flags & NTF_USE) { neigh_event_send(neigh, NULL); err = 0; - } else - err = __neigh_update(neigh, lladdr, ndm->ndm_state, flags, - NETLINK_CB(skb).portid, extack); - + } neigh_release(neigh); - out: return err; } |