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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 /net/ipv6/route.c
parentMerge tag 'rxrpc-fixes-20191220' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs (diff)
downloadlinux-dev-bd085ef678b2cc8c38c105673dfe8ff8f5ec0c57.tar.xz
linux-dev-bd085ef678b2cc8c38c105673dfe8ff8f5ec0c57.zip
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 'net/ipv6/route.c')
-rw-r--r--net/ipv6/route.c22
1 files changed, 15 insertions, 7 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index b59940416cb5..affb51c11a25 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -95,7 +95,8 @@ static int ip6_pkt_prohibit(struct sk_buff *skb);
static int ip6_pkt_prohibit_out(struct net *net, struct sock *sk, struct sk_buff *skb);
static void ip6_link_failure(struct sk_buff *skb);
static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
- struct sk_buff *skb, u32 mtu);
+ struct sk_buff *skb, u32 mtu,
+ bool confirm_neigh);
static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk,
struct sk_buff *skb);
static int rt6_score_route(const struct fib6_nh *nh, u32 fib6_flags, int oif,
@@ -264,7 +265,8 @@ static unsigned int ip6_blackhole_mtu(const struct dst_entry *dst)
}
static void ip6_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
- struct sk_buff *skb, u32 mtu)
+ struct sk_buff *skb, u32 mtu,
+ bool confirm_neigh)
{
}
@@ -2692,7 +2694,8 @@ static bool rt6_cache_allowed_for_pmtu(const struct rt6_info *rt)
}
static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk,
- const struct ipv6hdr *iph, u32 mtu)
+ const struct ipv6hdr *iph, u32 mtu,
+ bool confirm_neigh)
{
const struct in6_addr *daddr, *saddr;
struct rt6_info *rt6 = (struct rt6_info *)dst;
@@ -2710,7 +2713,10 @@ static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk,
daddr = NULL;
saddr = NULL;
}
- dst_confirm_neigh(dst, daddr);
+
+ if (confirm_neigh)
+ dst_confirm_neigh(dst, daddr);
+
mtu = max_t(u32, mtu, IPV6_MIN_MTU);
if (mtu >= dst_mtu(dst))
return;
@@ -2764,9 +2770,11 @@ out_unlock:
}
static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
- struct sk_buff *skb, u32 mtu)
+ struct sk_buff *skb, u32 mtu,
+ bool confirm_neigh)
{
- __ip6_rt_update_pmtu(dst, sk, skb ? ipv6_hdr(skb) : NULL, mtu);
+ __ip6_rt_update_pmtu(dst, sk, skb ? ipv6_hdr(skb) : NULL, mtu,
+ confirm_neigh);
}
void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
@@ -2785,7 +2793,7 @@ void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
dst = ip6_route_output(net, NULL, &fl6);
if (!dst->error)
- __ip6_rt_update_pmtu(dst, NULL, iph, ntohl(mtu));
+ __ip6_rt_update_pmtu(dst, NULL, iph, ntohl(mtu), true);
dst_release(dst);
}
EXPORT_SYMBOL_GPL(ip6_update_pmtu);