[PATCH v3 1/2] ip_tunnel: fix ip tunnel lookup in collect_md mode

[PATCH v3 1/2] ip_tunnel: fix ip tunnel lookup in collect_md mode

[Haishuang Yan]

In collect_md mode, if the tun dev is down, it still can call
ip_tunnel_rcv to receive on packets, and the rx statistics increase
improperly.

Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>

---
Change since v3:
  * Increment rx_dropped if tunnel device is not up, suggested by
  Pravin B Shelar
  * Fix wrong recipient addresss
---
 net/ipv4/ip_tunnel.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index e1856bf..5b2e542 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -176,8 +176,11 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn,
 		return cand;
 
 	t = rcu_dereference(itn->collect_md_tun);
-	if (t)
-		return t;
+	if (t) {
+		if (t->dev->flags & IFF_UP)
+			return t;
+		t->dev->stats.rx_dropped++;
+	}
 
 	if (itn->fb_tunnel_dev && itn->fb_tunnel_dev->flags & IFF_UP)
 		return netdev_priv(itn->fb_tunnel_dev);
-- 
1.8.3.1

[PATCH v3 2/2] ip6_tunnel: fix ip6 tunnel lookup in collect_md mode

[Haishuang Yan]

In collect_md mode, if the tun dev is down, it still can call
__ip6_tnl_rcv to receive on packets, and the rx statistics increase
improperly.

Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels")
Cc: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>

---
Change since v3:
  * Increment rx_dropped if tunnel device is not up, suggested by
  Pravin B Shelar
  * Fix wrong recipient address
---
 net/ipv6/ip6_tunnel.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 10a693a..e91d3b6 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -171,8 +171,11 @@ static struct net_device_stats *ip6_get_stats(struct net_device *dev)
 	}
 
 	t = rcu_dereference(ip6n->collect_md_tun);
-	if (t)
-		return t;
+	if (t) {
+		if (t->dev->flags & IFF_UP)
+			return t;
+		t->dev->stats.rx_dropped++;
+	}
 
 	t = rcu_dereference(ip6n->tnls_wc[0]);
 	if (t && (t->dev->flags & IFF_UP))
-- 
1.8.3.1

Re: [PATCH v3 2/2] ip6_tunnel: fix ip6 tunnel lookup in collect_md mode

[Alexei Starovoitov]

On 9/4/17 1:36 AM, Haishuang Yan wrote:
> In collect_md mode, if the tun dev is down, it still can call
> __ip6_tnl_rcv to receive on packets, and the rx statistics increase
> improperly.
>
> Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels")
> Cc: Alexei Starovoitov <ast@fb.com>
> Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
>
> ---
> Change since v3:
>   * Increment rx_dropped if tunnel device is not up, suggested by
>   Pravin B Shelar
>   * Fix wrong recipient address
> ---
>  net/ipv6/ip6_tunnel.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
> index 10a693a..e91d3b6 100644
> --- a/net/ipv6/ip6_tunnel.c
> +++ b/net/ipv6/ip6_tunnel.c
> @@ -171,8 +171,11 @@ static struct net_device_stats *ip6_get_stats(struct net_device *dev)
>  	}
>
>  	t = rcu_dereference(ip6n->collect_md_tun);
> -	if (t)
> -		return t;
> +	if (t) {
> +		if (t->dev->flags & IFF_UP)
> +			return t;
> +		t->dev->stats.rx_dropped++;
> +	}

Why increment the stats only for this drop case?
There are plenty of other conditions where packet
will be dropped in ip6 tunnel. I think it's important
to present consistent behavior to the users,
so I'd increment drop stats either for all drop cases
or for none. And today it's none.
The ! IFF_UP case should probably be return NULL too.

Re: [PATCH v3 2/2] ip6_tunnel: fix ip6 tunnel lookup in collect_md mode

[严海双]

> On 2017年9月6日, at 上午11:14, Alexei Starovoitov <ast@fb.com> wrote:
> 
> On 9/4/17 1:36 AM, Haishuang Yan wrote:
>> In collect_md mode, if the tun dev is down, it still can call
>> __ip6_tnl_rcv to receive on packets, and the rx statistics increase
>> improperly.
>> 
>> Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels")
>> Cc: Alexei Starovoitov <ast@fb.com>
>> Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
>> 
>> ---
>> Change since v3:
>>  * Increment rx_dropped if tunnel device is not up, suggested by
>>  Pravin B Shelar
>>  * Fix wrong recipient address
>> ---
>> net/ipv6/ip6_tunnel.c | 7 +++++--
>> 1 file changed, 5 insertions(+), 2 deletions(-)
>> 
>> diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
>> index 10a693a..e91d3b6 100644
>> --- a/net/ipv6/ip6_tunnel.c
>> +++ b/net/ipv6/ip6_tunnel.c
>> @@ -171,8 +171,11 @@ static struct net_device_stats *ip6_get_stats(struct net_device *dev)
>> 	}
>> 
>> 	t = rcu_dereference(ip6n->collect_md_tun);
>> -	if (t)
>> -		return t;
>> +	if (t) {
>> +		if (t->dev->flags & IFF_UP)
>> +			return t;
>> +		t->dev->stats.rx_dropped++;
>> +	}
> 
> Why increment the stats only for this drop case?
Because It was suggested by Pravin on v2 commit of the patch.

> There are plenty of other conditions where packet
> will be dropped in ip6 tunnel. I think it's important
> to present consistent behavior to the users,
> so I'd increment drop stats either for all drop cases
> or for none. And today it's none.
> The ! IFF_UP case should probably be return NULL too
> 
>