Re: [PATCHv2 net 3/3] sctp: do asoc update earlier in sctp_sf_do_dupcook_b

[Xin Long <lucien.xin@gmail.com>]

On Sat, May 1, 2021 at 12:57 PM Leppanen, Jere (Nokia - FI/Espoo)
<jere.leppanen@nokia.com> wrote:
>
> On Fri, 30 Apr 2021, Xin Long wrote:
>
> > The same thing should be done for sctp_sf_do_dupcook_b().
> > Meanwhile, SCTP_CMD_UPDATE_ASSOC cmd can be removed.
> >
> > v1->v2:
> >  - Fix the return value in sctp_sf_do_assoc_update().
> >
> > Signed-off-by: Xin Long <lucien.xin@gmail.com>
> > Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> > ---
> > include/net/sctp/command.h |  1 -
> > net/sctp/sm_sideeffect.c   | 26 -------------------------
> > net/sctp/sm_statefuns.c    | 47 +++++++++++++++++++++++++++++-----------------
> > 3 files changed, 30 insertions(+), 44 deletions(-)
> >
> > diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
> > index e8df72e..5e84888 100644
> > --- a/include/net/sctp/command.h
> > +++ b/include/net/sctp/command.h
> > @@ -68,7 +68,6 @@ enum sctp_verb {
> >       SCTP_CMD_ASSOC_FAILED,   /* Handle association failure. */
> >       SCTP_CMD_DISCARD_PACKET, /* Discard the whole packet. */
> >       SCTP_CMD_GEN_SHUTDOWN,   /* Generate a SHUTDOWN chunk. */
> > -     SCTP_CMD_UPDATE_ASSOC,   /* Update association information. */
> >       SCTP_CMD_PURGE_OUTQUEUE, /* Purge all data waiting to be sent. */
> >       SCTP_CMD_SETUP_T2,       /* Hi-level, setup T2-shutdown parms.  */
> >       SCTP_CMD_RTO_PENDING,    /* Set transport's rto_pending. */
> > diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
> > index 0948f14..ce15d59 100644
> > --- a/net/sctp/sm_sideeffect.c
> > +++ b/net/sctp/sm_sideeffect.c
> > @@ -826,28 +826,6 @@ static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
> >       asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
> > }
> >
> > -static void sctp_cmd_assoc_update(struct sctp_cmd_seq *cmds,
> > -                               struct sctp_association *asoc,
> > -                               struct sctp_association *new)
> > -{
> > -     struct net *net = asoc->base.net;
> > -     struct sctp_chunk *abort;
> > -
> > -     if (!sctp_assoc_update(asoc, new))
> > -             return;
> > -
> > -     abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
> > -     if (abort) {
> > -             sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
> > -             sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
> > -     }
> > -     sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
> > -     sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
> > -                     SCTP_PERR(SCTP_ERROR_RSRC_LOW));
> > -     SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
> > -     SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
> > -}
> > -
> > /* Helper function to change the state of an association. */
> > static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
> >                              struct sctp_association *asoc,
> > @@ -1301,10 +1279,6 @@ static int sctp_cmd_interpreter(enum sctp_event_type event_type,
> >                       sctp_endpoint_add_asoc(ep, asoc);
> >                       break;
> >
> > -             case SCTP_CMD_UPDATE_ASSOC:
> > -                    sctp_cmd_assoc_update(commands, asoc, cmd->obj.asoc);
> > -                    break;
> > -
> >               case SCTP_CMD_PURGE_OUTQUEUE:
> >                      sctp_outq_teardown(&asoc->outqueue);
> >                      break;
> > diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
> > index e8ccc4e..a428449 100644
> > --- a/net/sctp/sm_statefuns.c
> > +++ b/net/sctp/sm_statefuns.c
> > @@ -1773,6 +1773,30 @@ enum sctp_disposition sctp_sf_do_5_2_3_initack(
> >               return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
> > }
> >
> > +static int sctp_sf_do_assoc_update(struct sctp_association *asoc,
> > +                                struct sctp_association *new,
> > +                                struct sctp_cmd_seq *cmds)
> > +{
> > +     struct net *net = asoc->base.net;
> > +     struct sctp_chunk *abort;
> > +
> > +     if (!sctp_assoc_update(asoc, new))
> > +             return 0;
> > +
> > +     abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
> > +     if (abort) {
> > +             sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
> > +             sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
> > +     }
> > +     sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
> > +     sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
> > +                     SCTP_PERR(SCTP_ERROR_RSRC_LOW));
> > +     SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
> > +     SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
> > +
> > +     return -ENOMEM;
> > +}
> > +
> > /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
> >  *
> >  * Section 5.2.4
> > @@ -1853,21 +1877,8 @@ static enum sctp_disposition sctp_sf_do_dupcook_a(
> >       sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
> >
> >       /* Update the content of current association. */
> > -     if (sctp_assoc_update((struct sctp_association *)asoc, new_asoc)) {
> > -             struct sctp_chunk *abort;
> > -
> > -             abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
> > -             if (abort) {
> > -                     sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
> > -                     sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
> > -             }
> > -             sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
> > -             sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
> > -                             SCTP_PERR(SCTP_ERROR_RSRC_LOW));
> > -             SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
> > -             SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
> > +     if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
> >               goto nomem;
> > -     }
> >
> >       repl = sctp_make_cookie_ack(asoc, chunk);
> >       if (!repl)
> > @@ -1940,14 +1951,16 @@ static enum sctp_disposition sctp_sf_do_dupcook_b(
> >       if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
> >               return SCTP_DISPOSITION_DISCARD;
> >
> > -     /* 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_NEW_STATE,
> >                       SCTP_STATE(SCTP_STATE_ESTABLISHED));
> >       SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
> >       sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
> >
> > -     repl = sctp_make_cookie_ack(new_asoc, chunk);
> > +     /* Update the content of current association.  */
> > +     if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
> > +             goto nomem;
>
> Wouldn't it be better to do the update before SCTP_CMD_NEW_STATE?
> Or do we have some reason to move to SCTP_STATE_ESTABLISHED even
> if the update fails?
Yes, as sctp_sf_do_assoc_update() adds SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB),
and before that we have to keep SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB) added
in there, which is normally right after NEW_STATE cmd with ESTABLISHED.

>
> > +
> > +     repl = sctp_make_cookie_ack(asoc, chunk);
> >       if (!repl)
> >               goto nomem;
> >
> > --
> > 2.1.0