Subject: Re: [PATCH] sctp: Make "Invalid Stream Identifier" ERROR follows SACK when bundling

From: xufeng zhang <[email-masked]>
Date: Fri, 3 Aug 2012 10:24:03 +0800

On 08/03/2012 05:17 AM, Vlad Yasevich wrote:
> On 07/31/2012 02:51 AM, xufeng zhang wrote:
>> Sorry, please ignore the above patch, there was an paste error.
>> Please check the following patch.
>> ============================================
>> I'm wondering if the below solution is fine to you which is based on
>> your changes.
>> BTW, I have verified this patch and it works ok for all the situation,
>> but only one problem persists:
>> there is a potential that commands will exceeds SCTP_MAX_NUM_COMMANDS
>> which happens during sending lots of small error DATA chunks.
>>
>
> I started thinking along the same vein, but was thinking that maybe it 
> makes sense to make error list more generic. I need to check the spec 
> on the ordering of ERROR chunks.  If they are always after other 
> control chunks, then maybe make an error list and queue all errors 
> there.  Then when sending control chunks, drain the control queue 
> first, then the error queue, and finally the data queue.

I didn't find the explicitly bundling order description in spec for 
other ERROR chunks,
but it's reasonable to do this.
Anyway, I'll wait for your final solution.

Thanks,
Xufeng Zhang
>
> BTW, the patch below doesn't include the code to queue the error chunk 
> onto the new error queue.
>
> -vlad
>
>> Thanks,
>> Xufeng Zhang
>>
>> ---
>>   include/net/sctp/command.h |    1 +
>>   include/net/sctp/structs.h |    3 +++
>>   net/sctp/outqueue.c        |    7 +++++++
>>   net/sctp/sm_sideeffect.c   |   16 ++++++++++++++++
>>   net/sctp/sm_statefuns.c    |   17 ++++++++++++++---
>>   5 files changed, 41 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
>> index 712b3be..62c34f5 100644
>> --- a/include/net/sctp/command.h
>> +++ b/include/net/sctp/command.h
>> @@ -110,6 +110,7 @@ typedef enum {
>>          SCTP_CMD_SEND_NEXT_ASCONF, /* Send the next ASCONF after ACK */
>>          SCTP_CMD_PURGE_ASCONF_QUEUE, /* Purge all asconf queues.*/
>>          SCTP_CMD_SET_ASOC,       /* Restore association context */
>> +       SCTP_CMD_GEN_BAD_STREAM, /* Invalid Stream errors happened
>> command */
>>          SCTP_CMD_LAST
>>   } sctp_verb_t;
>>
>> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
>> index fc5e600..3d218e0 100644
>> --- a/include/net/sctp/structs.h
>> +++ b/include/net/sctp/structs.h
>> @@ -1183,6 +1183,9 @@ struct sctp_outq {
>>           */
>>          struct list_head abandoned;
>>
>> +       /* Put Invalid Stream error chunks on this list */
>> +       struct list_head bad_stream_err;
>> +
>>          /* How many unackd bytes do we have in-flight?  */
>>          __u32 outstanding_bytes;
>>
>> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
>> index e7aa177..1e87b0b 100644
>> --- a/net/sctp/outqueue.c
>> +++ b/net/sctp/outqueue.c
>> @@ -211,6 +211,7 @@ void sctp_outq_init(struct sctp_association *asoc,
>> struct sctp_outq *q)
>>          INIT_LIST_HEAD(&q->retransmit);
>>          INIT_LIST_HEAD(&q->sacked);
>>          INIT_LIST_HEAD(&q->abandoned);
>> +       INIT_LIST_HEAD(&q->bad_stream_err);
>>
>>          q->fast_rtx = 0;
>>          q->outstanding_bytes = 0;
>> @@ -283,6 +284,12 @@ void sctp_outq_teardown(struct sctp_outq *q)
>>                  list_del_init(&chunk->list);
>>                  sctp_chunk_free(chunk);
>>          }
>> +
>> +       /* Throw away any pending Invalid Stream error chunks */
>> +       list_for_each_entry_safe(chunk, tmp,&q->bad_stream_err, list) {
>> +               list_del_init(&chunk->list);
>> +               sctp_chunk_free(chunk);
>> +       }
>>   }
>>
>>   /* Free the outqueue structure and any related pending chunks.  */
>> diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
>> index fe99628..4698593 100644
>> --- a/net/sctp/sm_sideeffect.c
>> +++ b/net/sctp/sm_sideeffect.c
>> @@ -1060,6 +1060,18 @@ static void sctp_cmd_send_asconf(struct
>> sctp_association *asoc)
>>          }
>>   }
>>
>> +static void sctp_cmd_make_inv_stream_err(sctp_cmd_seq_t *commands,
>> +               struct sctp_association *asoc)
>> +{
>> +       struct sctp_chunk *err, *tmp;
>> +       struct sctp_outq *q =&asoc->outqueue;
>> +
>> +       list_for_each_entry_safe(err, tmp,&q->bad_stream_err, list) {
>> +               list_del_init(&err->list);
>> +               sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
>> +                               SCTP_CHUNK(err));
>> +       }
>> +}
>>
>>   /* These three macros allow us to pull the debugging code out of the
>>    * main flow of sctp_do_sm() to keep attention focused on the real
>> @@ -1724,6 +1736,10 @@ static int sctp_cmd_interpreter(sctp_event_t
>> event_type,
>>                          asoc = cmd->obj.asoc;
>>                          break;
>>
>> +               case SCTP_CMD_GEN_BAD_STREAM:
>> +                       sctp_cmd_make_inv_stream_err(commands, asoc);
>> +                       break;
>> +
>>                  default:
>>                          pr_warn("Impossible command: %u, %p\n",
>>                                  cmd->verb, cmd->obj.ptr);
>> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
>> index 9fca103..1c1bcd9 100644
>> --- a/net/sctp/sm_statefuns.c
>> +++ b/net/sctp/sm_statefuns.c
>> @@ -2967,8 +2967,14 @@ discard_force:
>>          return SCTP_DISPOSITION_DISCARD;
>>
>>   discard_noforce:
>> -       if (chunk->end_of_packet)
>> +       if (chunk->end_of_packet) {
>> +               struct sctp_outq *q =&asoc->outqueue;
>>                  sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
>> +               /* Queue the INVALID STREAM error after the SACK if one
>> is needed. */
>> +               if (!list_empty(&q->bad_stream_err))
>> +                       sctp_add_cmd_sf(commands, 
>> SCTP_CMD_GEN_BAD_STREAM,
>> +                                       SCTP_NULL());
>> +       }
>>
>>          return SCTP_DISPOSITION_DISCARD;
>>   consume:
>> @@ -3037,11 +3043,16 @@ sctp_disposition_t
>> sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep,
>>           * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown
>> timer
>>           */
>>          if (chunk->end_of_packet) {
>> +               struct sctp_outq *q =&asoc->outqueue;
>>                  /* We must delay the chunk creation since the 
>> cumulative
>>                   * TSN has not been updated yet.
>>                   */
>>                  sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN,
>> SCTP_NULL());
>>                  sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK,
>> SCTP_FORCE());
>> +               /* Queue the INVALID STREAM error after the SACK if one
>> is needed. */
>> +               if (!list_empty(&q->bad_stream_err))
>> +                       sctp_add_cmd_sf(commands, 
>> SCTP_CMD_GEN_BAD_STREAM,
>> +                                       SCTP_NULL());
>>                  sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
>>                                  
>> SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
>>          }
>> @@ -6136,6 +6147,7 @@ static int sctp_eat_data(const struct
>> sctp_association *asoc,
>>           */
>>          sid = ntohs(data_hdr->stream);
>>          if (sid>= asoc->c.sinit_max_instreams) {
>> +               struct sctp_outq *q =&asoc->outqueue;
>>                  /* Mark tsn as received even though we drop it */
>>                  sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN,
>> SCTP_U32(tsn));
>>
>> @@ -6144,8 +6156,7 @@ static int sctp_eat_data(const struct
>> sctp_association *asoc,
>>                                           sizeof(data_hdr->stream),
>>                                           sizeof(u16));
>>                  if (err)
>> -                       sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
>> -                                       SCTP_CHUNK(err));
>> +                       list_add_tail(&err->list,&q->bad_stream_err);
>>                  return SCTP_IERROR_BAD_STREAM;
>>          }
>>
>
>