[PATCH v2] sctp: set association state to established in dupcook_a handler

[PATCH v2] sctp: set association state to established in dupcook_a handler

[xufengzhang.main]

From: Xufeng Zhang <xufeng.zhang@windriver.com>

While sctp handling a duplicate COOKIE-ECHO and the action is
'Association restart', sctp_sf_do_dupcook_a() will processing
the unexpected COOKIE-ECHO for peer restart, but it does not set
the association state to SCTP_STATE_ESTABLISHED, so the association
could stuck in SCTP_STATE_SHUTDOWN_PENDING state forever.
This violates the sctp specification:
  RFC 4960 5.2.4. Handle a COOKIE ECHO when a TCB Exists
  Action
  A) In this case, the peer may have restarted. .....
     After this, the endpoint shall enter the ESTABLISHED state.

To resolve this problem, adding a SCTP_CMD_NEW_STATE cmd to the
command list before SCTP_CMD_REPLY cmd, this will set the restart
association to SCTP_STATE_ESTABLISHED state properly and also avoid
I-bit being set in the DATA chunk header when COOKIE_ACK is bundled
with DATA chunks.

Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com>
---
v2:
- Put the SCTP_CMD_NEW_STATE command before SCTP_CMD_REPLY and after SCTP_CMD_EVENT_ULP
  suggested by Vlad and Neil
- Improve the last paragraph of the commit header
 
 net/sctp/sm_statefuns.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 618ec7e..5131fcf 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1779,8 +1779,10 @@ static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
 
 	/* Update the content of current association. */
 	sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
-	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
 	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
+	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+			SCTP_STATE(SCTP_STATE_ESTABLISHED));
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
 	return SCTP_DISPOSITION_CONSUME;
 
 nomem_ev:
-- 
1.7.0.2

Re: [PATCH v2] sctp: set association state to established in dupcook_a handler

[Neil Horman]

On Thu, Jan 24, 2013 at 10:44:34AM +0800, xufengzhang.main@gmail.com wrote:
> From: Xufeng Zhang <xufeng.zhang@windriver.com>
> 
> While sctp handling a duplicate COOKIE-ECHO and the action is
> 'Association restart', sctp_sf_do_dupcook_a() will processing
> the unexpected COOKIE-ECHO for peer restart, but it does not set
> the association state to SCTP_STATE_ESTABLISHED, so the association
> could stuck in SCTP_STATE_SHUTDOWN_PENDING state forever.
> This violates the sctp specification:
>   RFC 4960 5.2.4. Handle a COOKIE ECHO when a TCB Exists
>   Action
>   A) In this case, the peer may have restarted. .....
>      After this, the endpoint shall enter the ESTABLISHED state.
> 
> To resolve this problem, adding a SCTP_CMD_NEW_STATE cmd to the
> command list before SCTP_CMD_REPLY cmd, this will set the restart
> association to SCTP_STATE_ESTABLISHED state properly and also avoid
> I-bit being set in the DATA chunk header when COOKIE_ACK is bundled
> with DATA chunks.
> 
> Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com>
> ---
> v2:
> - Put the SCTP_CMD_NEW_STATE command before SCTP_CMD_REPLY and after SCTP_CMD_EVENT_ULP
>   suggested by Vlad and Neil
> - Improve the last paragraph of the commit header
>  
>  net/sctp/sm_statefuns.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
> index 618ec7e..5131fcf 100644
> --- a/net/sctp/sm_statefuns.c
> +++ b/net/sctp/sm_statefuns.c
> @@ -1779,8 +1779,10 @@ static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
>  
>  	/* Update the content of current association. */
>  	sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
> -	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
>  	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
> +	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
> +			SCTP_STATE(SCTP_STATE_ESTABLISHED));
> +	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
>  	return SCTP_DISPOSITION_CONSUME;
>  
>  nomem_ev:
> -- 
> 1.7.0.2
> 
> 
Acked-by: Neil Horman <nhorman@tuxdriver.com>

Re: [PATCH v2] sctp: set association state to established in dupcook_a handler

[Vlad Yasevich]

On 01/23/2013 09:44 PM, xufengzhang.main@gmail.com wrote:
> From: Xufeng Zhang <xufeng.zhang@windriver.com>
>
> While sctp handling a duplicate COOKIE-ECHO and the action is
> 'Association restart', sctp_sf_do_dupcook_a() will processing
> the unexpected COOKIE-ECHO for peer restart, but it does not set
> the association state to SCTP_STATE_ESTABLISHED, so the association
> could stuck in SCTP_STATE_SHUTDOWN_PENDING state forever.
> This violates the sctp specification:
>    RFC 4960 5.2.4. Handle a COOKIE ECHO when a TCB Exists
>    Action
>    A) In this case, the peer may have restarted. .....
>       After this, the endpoint shall enter the ESTABLISHED state.
>
> To resolve this problem, adding a SCTP_CMD_NEW_STATE cmd to the
> command list before SCTP_CMD_REPLY cmd, this will set the restart
> association to SCTP_STATE_ESTABLISHED state properly and also avoid
> I-bit being set in the DATA chunk header when COOKIE_ACK is bundled
> with DATA chunks.
>
> Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com>

Acked-by: Vlad Yasevich <vyasevich@gmail.com>

-vlad

> ---
> v2:
> - Put the SCTP_CMD_NEW_STATE command before SCTP_CMD_REPLY and after SCTP_CMD_EVENT_ULP
>    suggested by Vlad and Neil
> - Improve the last paragraph of the commit header
>
>   net/sctp/sm_statefuns.c |    4 +++-
>   1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
> index 618ec7e..5131fcf 100644
> --- a/net/sctp/sm_statefuns.c
> +++ b/net/sctp/sm_statefuns.c
> @@ -1779,8 +1779,10 @@ static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
>
>   	/* Update the content of current association. */
>   	sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
> -	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
>   	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
> +	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
> +			SCTP_STATE(SCTP_STATE_ESTABLISHED));
> +	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
>   	return SCTP_DISPOSITION_CONSUME;
>
>   nomem_ev:
>

Re: [PATCH v2] sctp: set association state to established in dupcook_a handler

[David Miller]

From: Vlad Yasevich <vyasevich@gmail.com>
Date: Thu, 24 Jan 2013 10:05:37 -0500

> On 01/23/2013 09:44 PM, xufengzhang.main@gmail.com wrote:
>> From: Xufeng Zhang <xufeng.zhang@windriver.com>
>>
>> While sctp handling a duplicate COOKIE-ECHO and the action is
>> 'Association restart', sctp_sf_do_dupcook_a() will processing
>> the unexpected COOKIE-ECHO for peer restart, but it does not set
>> the association state to SCTP_STATE_ESTABLISHED, so the association
>> could stuck in SCTP_STATE_SHUTDOWN_PENDING state forever.
>> This violates the sctp specification:
>>    RFC 4960 5.2.4. Handle a COOKIE ECHO when a TCB Exists
>>    Action
>>    A) In this case, the peer may have restarted. .....
>>       After this, the endpoint shall enter the ESTABLISHED state.
>>
>> To resolve this problem, adding a SCTP_CMD_NEW_STATE cmd to the
>> command list before SCTP_CMD_REPLY cmd, this will set the restart
>> association to SCTP_STATE_ESTABLISHED state properly and also avoid
>> I-bit being set in the DATA chunk header when COOKIE_ACK is bundled
>> with DATA chunks.
>>
>> Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com>
> 
> Acked-by: Vlad Yasevich <vyasevich@gmail.com>

Applied, thanks everyone.