path: root/include/net
diff options
authorHangbin Liu <liuhangbin@gmail.com>2019-12-22 10:51:09 +0800
committerDavid S. Miller <davem@davemloft.net>2019-12-24 22:28:54 -0800
commitbd085ef678b2cc8c38c105673dfe8ff8f5ec0c57 (patch)
treefdb14c22c29f1c93149e3acd0f5c6edcffb6769b /include/net
parentMerge tag 'rxrpc-fixes-20191220' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs (diff)
net: add bool confirm_neigh parameter for dst_ops.update_pmtu
The MTU update code is supposed to be invoked in response to real networking events that update the PMTU. In IPv6 PMTU update function __ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor confirmed time. But for tunnel code, it will call pmtu before xmit, like: - tnl_update_pmtu() - skb_dst_update_pmtu() - ip6_rt_update_pmtu() - __ip6_rt_update_pmtu() - dst_confirm_neigh() If the tunnel remote dst mac address changed and we still do the neigh confirm, we will not be able to update neigh cache and ping6 remote will failed. So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we should not be invoking dst_confirm_neigh() as we have no evidence of successful two-way communication at this point. On the other hand it is also important to keep the neigh reachability fresh for TCP flows, so we cannot remove this dst_confirm_neigh() call. To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu to choose whether we should do neigh update or not. I will add the parameter in this patch and set all the callers to true to comply with the previous way, and fix the tunnel code one by one on later patches. v5: No change. v4: No change. v3: Do not remove dst_confirm_neigh, but add a new bool parameter in dst_ops.update_pmtu to control whether we should do neighbor confirm. Also split the big patch to small ones for each area. v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu. Suggested-by: David Miller <davem@davemloft.net> Reviewed-by: Guillaume Nault <gnault@redhat.com> Acked-by: David Ahern <dsahern@gmail.com> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
2 files changed, 3 insertions, 2 deletions
diff --git a/include/net/dst.h b/include/net/dst.h
index 8224dad2ae94..593630e0e076 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -516,7 +516,7 @@ static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu)
struct dst_entry *dst = skb_dst(skb);
if (dst && dst->ops->update_pmtu)
- dst->ops->update_pmtu(dst, NULL, skb, mtu);
+ dst->ops->update_pmtu(dst, NULL, skb, mtu, true);
static inline void skb_tunnel_check_pmtu(struct sk_buff *skb,
diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h
index 5ec645f27ee3..443863c7b8da 100644
--- a/include/net/dst_ops.h
+++ b/include/net/dst_ops.h
@@ -27,7 +27,8 @@ struct dst_ops {
struct dst_entry * (*negative_advice)(struct dst_entry *);
void (*link_failure)(struct sk_buff *);
void (*update_pmtu)(struct dst_entry *dst, struct sock *sk,
- struct sk_buff *skb, u32 mtu);
+ struct sk_buff *skb, u32 mtu,
+ bool confirm_neigh);
void (*redirect)(struct dst_entry *dst, struct sock *sk,
struct sk_buff *skb);
int (*local_out)(struct net *net, struct sock *sk, struct sk_buff *skb);