Re: [PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-28 Thread David Ahern 
On 12/27/16 12:03 PM, David Miller wrote:
> From: Wei Zhang 
> Date: Tue, 27 Dec 2016 17:52:24 +0800
> 
>> When we send a packet for our own local address on a non-loopback
>> interface (e.g. eth0), due to the change had been introduced from
>> commit 0b922b7a829c ("net: original ingress device index in PKTINFO"), the
>> original ingress device index would be set as the loopback interface.
>> However, the packet should be considered as if it is being arrived via the
>> sending interface (eth0), otherwise it would break the expectation of the
>> userspace application (e.g. the DHCPRELEASE message from dhcp_release
>> binary would be ignored by the dnsmasq daemon, since it come from lo which
>> is not the interface dnsmasq bind to)
>>

Add a Fixes line before the sign-off:

Fixes: 0b922b7a829c ("net: original ingress device index in PKTINFO")
>> Signed-off-by: Wei Zhang 
> 
> When you are fixing a problem introduced by another change, always CC:
> the author of that change as I have done so here.
> 
> David, please take a look at this, thanks.
> 
>> ---
>>  net/ipv4/ip_sockglue.c | 8 +++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
>> index b8a2d63..76d78a7 100644
>> --- a/net/ipv4/ip_sockglue.c
>> +++ b/net/ipv4/ip_sockglue.c
>> @@ -1202,8 +1202,14 @@ void ipv4_pktinfo_prepare(const struct sock *sk, 
>> struct sk_buff *skb)
>>   * which has interface index (iif) as the first member of the
>>   * underlying inet{6}_skb_parm struct. This code then overlays
>>   * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
>> - * element so the iif is picked up from the prior IPCB
>> + * element so the iif is picked up from the prior IPCB except
>> + * iif is loopback interface which the packet should be
>> + * considered as if it is being arrived via the sending
>> + * interface

That comment change could use an adjustment (adjust to fit with in the 80 
columns):

element so the iif is picked up from the prior IPCB. If iif
is the loopback interface, then return the sending interface
(e.g., process binds socket to eth0 for Tx which is redirected
to loopback in the rtable/dst).


>>   */
>> +if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX)
>> +pktinfo->ipi_ifindex = inet_iif(skb);
>> +
>>  pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
>>  } else {
>>  pktinfo->ipi_ifindex = 0;


The actual change looks ok to me.

Acked-by: David Ahern

Re: [PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-28 Thread David Ahern 
On 12/27/16 12:03 PM, David Miller wrote:
> From: Wei Zhang 
> Date: Tue, 27 Dec 2016 17:52:24 +0800
> 
>> When we send a packet for our own local address on a non-loopback
>> interface (e.g. eth0), due to the change had been introduced from
>> commit 0b922b7a829c ("net: original ingress device index in PKTINFO"), the
>> original ingress device index would be set as the loopback interface.
>> However, the packet should be considered as if it is being arrived via the
>> sending interface (eth0), otherwise it would break the expectation of the
>> userspace application (e.g. the DHCPRELEASE message from dhcp_release
>> binary would be ignored by the dnsmasq daemon, since it come from lo which
>> is not the interface dnsmasq bind to)
>>

Add a Fixes line before the sign-off:

Fixes: 0b922b7a829c ("net: original ingress device index in PKTINFO")
>> Signed-off-by: Wei Zhang 
> 
> When you are fixing a problem introduced by another change, always CC:
> the author of that change as I have done so here.
> 
> David, please take a look at this, thanks.
> 
>> ---
>>  net/ipv4/ip_sockglue.c | 8 +++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
>> index b8a2d63..76d78a7 100644
>> --- a/net/ipv4/ip_sockglue.c
>> +++ b/net/ipv4/ip_sockglue.c
>> @@ -1202,8 +1202,14 @@ void ipv4_pktinfo_prepare(const struct sock *sk, 
>> struct sk_buff *skb)
>>   * which has interface index (iif) as the first member of the
>>   * underlying inet{6}_skb_parm struct. This code then overlays
>>   * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
>> - * element so the iif is picked up from the prior IPCB
>> + * element so the iif is picked up from the prior IPCB except
>> + * iif is loopback interface which the packet should be
>> + * considered as if it is being arrived via the sending
>> + * interface

That comment change could use an adjustment (adjust to fit with in the 80 
columns):

element so the iif is picked up from the prior IPCB. If iif
is the loopback interface, then return the sending interface
(e.g., process binds socket to eth0 for Tx which is redirected
to loopback in the rtable/dst).


>>   */
>> +if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX)
>> +pktinfo->ipi_ifindex = inet_iif(skb);
>> +
>>  pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
>>  } else {
>>  pktinfo->ipi_ifindex = 0;


The actual change looks ok to me.

Acked-by: David Ahern

Re: [PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-27 Thread David Miller 
From: Wei Zhang 
Date: Tue, 27 Dec 2016 17:52:24 +0800

> When we send a packet for our own local address on a non-loopback
> interface (e.g. eth0), due to the change had been introduced from
> commit 0b922b7a829c ("net: original ingress device index in PKTINFO"), the
> original ingress device index would be set as the loopback interface.
> However, the packet should be considered as if it is being arrived via the
> sending interface (eth0), otherwise it would break the expectation of the
> userspace application (e.g. the DHCPRELEASE message from dhcp_release
> binary would be ignored by the dnsmasq daemon, since it come from lo which
> is not the interface dnsmasq bind to)
> 
> Signed-off-by: Wei Zhang 

When you are fixing a problem introduced by another change, always CC:
the author of that change as I have done so here.

David, please take a look at this, thanks.

> ---
>  net/ipv4/ip_sockglue.c | 8 +++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index b8a2d63..76d78a7 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -1202,8 +1202,14 @@ void ipv4_pktinfo_prepare(const struct sock *sk, 
> struct sk_buff *skb)
>* which has interface index (iif) as the first member of the
>* underlying inet{6}_skb_parm struct. This code then overlays
>* PKTINFO_SKB_CB and in_pktinfo also has iif as the first
> -  * element so the iif is picked up from the prior IPCB
> +  * element so the iif is picked up from the prior IPCB except
> +  * iif is loopback interface which the packet should be
> +  * considered as if it is being arrived via the sending
> +  * interface
>*/
> + if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX)
> + pktinfo->ipi_ifindex = inet_iif(skb);
> +
>   pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
>   } else {
>   pktinfo->ipi_ifindex = 0;
> -- 
> 1.8.3.1
> 
>

Re: [PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-27 Thread David Miller 
From: Wei Zhang 
Date: Tue, 27 Dec 2016 17:52:24 +0800

> When we send a packet for our own local address on a non-loopback
> interface (e.g. eth0), due to the change had been introduced from
> commit 0b922b7a829c ("net: original ingress device index in PKTINFO"), the
> original ingress device index would be set as the loopback interface.
> However, the packet should be considered as if it is being arrived via the
> sending interface (eth0), otherwise it would break the expectation of the
> userspace application (e.g. the DHCPRELEASE message from dhcp_release
> binary would be ignored by the dnsmasq daemon, since it come from lo which
> is not the interface dnsmasq bind to)
> 
> Signed-off-by: Wei Zhang 

When you are fixing a problem introduced by another change, always CC:
the author of that change as I have done so here.

David, please take a look at this, thanks.

> ---
>  net/ipv4/ip_sockglue.c | 8 +++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index b8a2d63..76d78a7 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -1202,8 +1202,14 @@ void ipv4_pktinfo_prepare(const struct sock *sk, 
> struct sk_buff *skb)
>* which has interface index (iif) as the first member of the
>* underlying inet{6}_skb_parm struct. This code then overlays
>* PKTINFO_SKB_CB and in_pktinfo also has iif as the first
> -  * element so the iif is picked up from the prior IPCB
> +  * element so the iif is picked up from the prior IPCB except
> +  * iif is loopback interface which the packet should be
> +  * considered as if it is being arrived via the sending
> +  * interface
>*/
> + if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX)
> + pktinfo->ipi_ifindex = inet_iif(skb);
> +
>   pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
>   } else {
>   pktinfo->ipi_ifindex = 0;
> -- 
> 1.8.3.1
> 
>

Re: [PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-27 Thread Sergei Shtylyov 

Hello!

On 12/27/2016 10:52 AM, Wei Zhang wrote:


When we send a packet for our own local address on a non-loopback interface
(e.g. eth0), due to the change had been introduced from commit 0b922b7a829c
("net: original ingress device index in PKTINFO"), the original ingress
device index would be set as the loopback interface. However, the packet
should be considered as if it is being arrived via the sending interface
(eth0), otherwise it would break the expectation of the userspace
application (e.g. the DHCPRELEASE message from dhcp_release binary would
be ignored by the dnsmasq daemon)

Signed-off-by: Wei Zhang 
---
 net/ipv4/ip_sockglue.c | 7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index b8a2d63..b6a6d35 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1202,8 +1202,13 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct 
sk_buff *skb)
 * which has interface index (iif) as the first member of the
 * underlying inet{6}_skb_parm struct. This code then overlays
 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
-* element so the iif is picked up from the prior IPCB
+* element so the iif is picked up from the prior IPCB except
+* iif is loopback interface which the packet should be


   Tail space.


+* considered as if it is being arrived via the sending 
interface
 */
+   if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX) {
+   pktinfo->ipi_ifindex = inet_iif(skb);
+   }


   {} not needed here.


pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
} else {
pktinfo->ipi_ifindex = 0;


MBR, Sergei

Re: [PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-27 Thread Sergei Shtylyov 

Hello!

On 12/27/2016 10:52 AM, Wei Zhang wrote:


When we send a packet for our own local address on a non-loopback interface
(e.g. eth0), due to the change had been introduced from commit 0b922b7a829c
("net: original ingress device index in PKTINFO"), the original ingress
device index would be set as the loopback interface. However, the packet
should be considered as if it is being arrived via the sending interface
(eth0), otherwise it would break the expectation of the userspace
application (e.g. the DHCPRELEASE message from dhcp_release binary would
be ignored by the dnsmasq daemon)

Signed-off-by: Wei Zhang 
---
 net/ipv4/ip_sockglue.c | 7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index b8a2d63..b6a6d35 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1202,8 +1202,13 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct 
sk_buff *skb)
 * which has interface index (iif) as the first member of the
 * underlying inet{6}_skb_parm struct. This code then overlays
 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
-* element so the iif is picked up from the prior IPCB
+* element so the iif is picked up from the prior IPCB except
+* iif is loopback interface which the packet should be


   Tail space.


+* considered as if it is being arrived via the sending 
interface
 */
+   if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX) {
+   pktinfo->ipi_ifindex = inet_iif(skb);
+   }


   {} not needed here.


pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
} else {
pktinfo->ipi_ifindex = 0;


MBR, Sergei

[PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-27 Thread Wei Zhang 
When we send a packet for our own local address on a non-loopback
interface (e.g. eth0), due to the change had been introduced from
commit 0b922b7a829c ("net: original ingress device index in PKTINFO"), the
original ingress device index would be set as the loopback interface.
However, the packet should be considered as if it is being arrived via the
sending interface (eth0), otherwise it would break the expectation of the
userspace application (e.g. the DHCPRELEASE message from dhcp_release
binary would be ignored by the dnsmasq daemon, since it come from lo which
is not the interface dnsmasq bind to)

Signed-off-by: Wei Zhang 
---
 net/ipv4/ip_sockglue.c | 8 +++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index b8a2d63..76d78a7 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1202,8 +1202,14 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct 
sk_buff *skb)
 * which has interface index (iif) as the first member of the
 * underlying inet{6}_skb_parm struct. This code then overlays
 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
-* element so the iif is picked up from the prior IPCB
+* element so the iif is picked up from the prior IPCB except
+* iif is loopback interface which the packet should be
+* considered as if it is being arrived via the sending
+* interface
 */
+   if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX)
+   pktinfo->ipi_ifindex = inet_iif(skb);
+
pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
} else {
pktinfo->ipi_ifindex = 0;
-- 
1.8.3.1

[PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-27 Thread Wei Zhang 
When we send a packet for our own local address on a non-loopback
interface (e.g. eth0), due to the change had been introduced from
commit 0b922b7a829c ("net: original ingress device index in PKTINFO"), the
original ingress device index would be set as the loopback interface.
However, the packet should be considered as if it is being arrived via the
sending interface (eth0), otherwise it would break the expectation of the
userspace application (e.g. the DHCPRELEASE message from dhcp_release
binary would be ignored by the dnsmasq daemon, since it come from lo which
is not the interface dnsmasq bind to)

Signed-off-by: Wei Zhang 
---
 net/ipv4/ip_sockglue.c | 8 +++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index b8a2d63..76d78a7 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1202,8 +1202,14 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct 
sk_buff *skb)
 * which has interface index (iif) as the first member of the
 * underlying inet{6}_skb_parm struct. This code then overlays
 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
-* element so the iif is picked up from the prior IPCB
+* element so the iif is picked up from the prior IPCB except
+* iif is loopback interface which the packet should be
+* considered as if it is being arrived via the sending
+* interface
 */
+   if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX)
+   pktinfo->ipi_ifindex = inet_iif(skb);
+
pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
} else {
pktinfo->ipi_ifindex = 0;
-- 
1.8.3.1

Re:[PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-27 Thread wei zhang 
At 2016-12-27 15:52:18, "Wei Zhang"  wrote:
>When we send a packet for our own local address on a non-loopback interface
>(e.g. eth0), due to the change had been introduced from commit 0b922b7a829c
>("net: original ingress device index in PKTINFO"), the original ingress
>device index would be set as the loopback interface. However, the packet
>should be considered as if it is being arrived via the sending interface
>(eth0), otherwise it would break the expectation of the userspace
>application (e.g. the DHCPRELEASE message from dhcp_release binary would
>be ignored by the dnsmasq daemon)
>
>Signed-off-by: Wei Zhang 
>---
> net/ipv4/ip_sockglue.c | 7 ++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
>diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
>index b8a2d63..b6a6d35 100644
>--- a/net/ipv4/ip_sockglue.c
>+++ b/net/ipv4/ip_sockglue.c
>@@ -1202,8 +1202,13 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct 
>sk_buff *skb)
>* which has interface index (iif) as the first member of the
>* underlying inet{6}_skb_parm struct. This code then overlays
>* PKTINFO_SKB_CB and in_pktinfo also has iif as the first
>-   * element so the iif is picked up from the prior IPCB
>+   * element so the iif is picked up from the prior IPCB except
>+   * iif is loopback interface which the packet should be 
>+   * considered as if it is being arrived via the sending 
>interface
>*/
>+  if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX) {
>+  pktinfo->ipi_ifindex = inet_iif(skb);
>+  }
>   pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
>   } else {
>   pktinfo->ipi_ifindex = 0;
>-- 
>1.8.3.1
>

  When I upgrade to the 4.9, the dhcp_release could not release the dhcp
lease, the dnsmasq ignored all the DHCPRELEASE message which it think come
from lo. I think this is due to the commit 0b922b7a829c, which set the
IPCB(skb)->iif = skb->skb_iif in the ip_rcv()!

  And I'm very sorry about forgetting checkpatch, I will resend the patch,
hope I'm not bothering you!

Thanks,
Wei Zhang

Re:[PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-27 Thread wei zhang 
At 2016-12-27 15:52:18, "Wei Zhang"  wrote:
>When we send a packet for our own local address on a non-loopback interface
>(e.g. eth0), due to the change had been introduced from commit 0b922b7a829c
>("net: original ingress device index in PKTINFO"), the original ingress
>device index would be set as the loopback interface. However, the packet
>should be considered as if it is being arrived via the sending interface
>(eth0), otherwise it would break the expectation of the userspace
>application (e.g. the DHCPRELEASE message from dhcp_release binary would
>be ignored by the dnsmasq daemon)
>
>Signed-off-by: Wei Zhang 
>---
> net/ipv4/ip_sockglue.c | 7 ++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
>diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
>index b8a2d63..b6a6d35 100644
>--- a/net/ipv4/ip_sockglue.c
>+++ b/net/ipv4/ip_sockglue.c
>@@ -1202,8 +1202,13 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct 
>sk_buff *skb)
>* which has interface index (iif) as the first member of the
>* underlying inet{6}_skb_parm struct. This code then overlays
>* PKTINFO_SKB_CB and in_pktinfo also has iif as the first
>-   * element so the iif is picked up from the prior IPCB
>+   * element so the iif is picked up from the prior IPCB except
>+   * iif is loopback interface which the packet should be 
>+   * considered as if it is being arrived via the sending 
>interface
>*/
>+  if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX) {
>+  pktinfo->ipi_ifindex = inet_iif(skb);
>+  }
>   pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
>   } else {
>   pktinfo->ipi_ifindex = 0;
>-- 
>1.8.3.1
>

  When I upgrade to the 4.9, the dhcp_release could not release the dhcp
lease, the dnsmasq ignored all the DHCPRELEASE message which it think come
from lo. I think this is due to the commit 0b922b7a829c, which set the
IPCB(skb)->iif = skb->skb_iif in the ip_rcv()!

  And I'm very sorry about forgetting checkpatch, I will resend the patch,
hope I'm not bothering you!

Thanks,
Wei Zhang

[PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-26 Thread Wei Zhang 
When we send a packet for our own local address on a non-loopback interface
(e.g. eth0), due to the change had been introduced from commit 0b922b7a829c
("net: original ingress device index in PKTINFO"), the original ingress
device index would be set as the loopback interface. However, the packet
should be considered as if it is being arrived via the sending interface
(eth0), otherwise it would break the expectation of the userspace
application (e.g. the DHCPRELEASE message from dhcp_release binary would
be ignored by the dnsmasq daemon)

Signed-off-by: Wei Zhang 
---
 net/ipv4/ip_sockglue.c | 7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index b8a2d63..b6a6d35 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1202,8 +1202,13 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct 
sk_buff *skb)
 * which has interface index (iif) as the first member of the
 * underlying inet{6}_skb_parm struct. This code then overlays
 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
-* element so the iif is picked up from the prior IPCB
+* element so the iif is picked up from the prior IPCB except
+* iif is loopback interface which the packet should be 
+* considered as if it is being arrived via the sending 
interface
 */
+   if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX) {
+   pktinfo->ipi_ifindex = inet_iif(skb);
+   }
pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
} else {
pktinfo->ipi_ifindex = 0;
-- 
1.8.3.1

[PATCH] net: fix incorrect original ingress device index in PKTINFO

2016-12-26 Thread Wei Zhang 
When we send a packet for our own local address on a non-loopback interface
(e.g. eth0), due to the change had been introduced from commit 0b922b7a829c
("net: original ingress device index in PKTINFO"), the original ingress
device index would be set as the loopback interface. However, the packet
should be considered as if it is being arrived via the sending interface
(eth0), otherwise it would break the expectation of the userspace
application (e.g. the DHCPRELEASE message from dhcp_release binary would
be ignored by the dnsmasq daemon)

Signed-off-by: Wei Zhang 
---
 net/ipv4/ip_sockglue.c | 7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index b8a2d63..b6a6d35 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1202,8 +1202,13 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct 
sk_buff *skb)
 * which has interface index (iif) as the first member of the
 * underlying inet{6}_skb_parm struct. This code then overlays
 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
-* element so the iif is picked up from the prior IPCB
+* element so the iif is picked up from the prior IPCB except
+* iif is loopback interface which the packet should be 
+* considered as if it is being arrived via the sending 
interface
 */
+   if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX) {
+   pktinfo->ipi_ifindex = inet_iif(skb);
+   }
pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
} else {
pktinfo->ipi_ifindex = 0;
-- 
1.8.3.1