[PATCH] sctp: Fix to handle SHUTDOWN in SHUTDOWN-PENDING state

[PATCH] sctp: Fix to handle SHUTDOWN in SHUTDOWN-PENDING state

[Wei Yongjun]

If SHUTDOWN is received in SHUTDOWN-PENDING state, enpoint should enter
the SHUTDOWN-RECEIVED state and check the Cumulative TSN Ack field of
the SHUTDOWN chunk (RFC 4960 Section 9.2). If the SHUTDOWN chunk can
acknowledge all of the send DATA chunks, SHUTDOWN-ACK should be sent.

But now endpoint just silently discarded the SHUTDOWN chunk.

SHUTDOWN received in SHUTDOWN-PENDING state can happend when the last
SACK is lost by network, or the SHUTDOWN chunk can acknowledge all of
the received DATA chunks. The packet sequence(SACK lost) is like this:

Endpoint A                       Endpoint B       ULP
(ESTABLISHED)                    (ESTABLISHED)

               <-----------      DATA
                                             <--- shutdown
                                 Enter SHUTDOWN-PENDING state
  SACK         ----lost---->

  SHUTDOWN(*1) ------------>

               <-----------      SHUTDOWN-ACK

 (*1) silently discarded now.

This patch fix to handle SHUTDOWN in SHUTDOWN-PENDING state as the same
as ESTABLISHED state.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
---
 net/sctp/sm_statetable.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c
index dd4ddc4..a5b5590 100644
--- a/net/sctp/sm_statetable.c
+++ b/net/sctp/sm_statetable.c
@@ -266,7 +266,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
 	/* SCTP_STATE_ESTABLISHED */ \
 	TYPE_SCTP_FUNC(sctp_sf_do_9_2_shutdown), \
 	/* SCTP_STATE_SHUTDOWN_PENDING */ \
-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
+	TYPE_SCTP_FUNC(sctp_sf_do_9_2_shutdown), \
 	/* SCTP_STATE_SHUTDOWN_SENT */ \
 	TYPE_SCTP_FUNC(sctp_sf_do_9_2_shutdown_ack), \
 	/* SCTP_STATE_SHUTDOWN_RECEIVED */ \
-- 
1.5.3.8

[PATCH] sctp: Fix to handle SHUTDOWN in SHUTDOWN_RECEIVED state

[Wei Yongjun]

Once an endpoint has reached the SHUTDOWN-RECEIVED state,
it MUST NOT send a SHUTDOWN in response to a ULP request.
The Cumulative TSN Ack of the received SHUTDOWN chunk
MUST be processed.

This patch fix to process Cumulative TSN Ack of the received
SHUTDOWN chunk in SHUTDOWN_RECEIVED state.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
---
 include/net/sctp/sm.h    |    1 +
 net/sctp/sm_statefuns.c  |   45 +++++++++++++++++++++++++++++++++++++++++++++
 net/sctp/sm_statetable.c |    2 +-
 3 files changed, 47 insertions(+), 1 deletions(-)

diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index 029a54a..c1dd893 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -125,6 +125,7 @@ sctp_state_fn_t sctp_sf_beat_8_3;
 sctp_state_fn_t sctp_sf_backbeat_8_3;
 sctp_state_fn_t sctp_sf_do_9_2_final;
 sctp_state_fn_t sctp_sf_do_9_2_shutdown;
+sctp_state_fn_t sctp_sf_do_9_2_shut_ctsn;
 sctp_state_fn_t sctp_sf_do_ecn_cwr;
 sctp_state_fn_t sctp_sf_do_ecne;
 sctp_state_fn_t sctp_sf_ootb;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index d4c3fbc..50afd27 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -2599,6 +2599,51 @@ out:
 	return disposition;
 }
 
+/*
+ * sctp_sf_do_9_2_shut_ctsn
+ *
+ * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
+ * it MUST NOT send a SHUTDOWN in response to a ULP request.
+ * The Cumulative TSN Ack of the received SHUTDOWN chunk
+ * MUST be processed.
+ */
+sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep,
+					   const struct sctp_association *asoc,
+					   const sctp_subtype_t type,
+					   void *arg,
+					   sctp_cmd_seq_t *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	sctp_shutdownhdr_t *sdh;
+
+	if (!sctp_vtag_verify(chunk, asoc))
+		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
+
+	/* Make sure that the SHUTDOWN chunk has a valid length. */
+	if (!sctp_chunk_length_valid(chunk,
+				      sizeof(struct sctp_shutdown_chunk_t)))
+		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
+						  commands);
+
+	sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
+
+	/* If Cumulative TSN Ack beyond the max tsn currently
+	 * send, terminating the association and respond to the
+	 * sender with an ABORT.
+	 */
+	if (!TSN_lt(ntohl(sdh->cum_tsn_ack), asoc->next_tsn))
+		return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
+
+	/* verify, by checking the Cumulative TSN Ack field of the
+	 * chunk, that all its outstanding DATA chunks have been
+	 * received by the SHUTDOWN sender.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
+			SCTP_BE32(sdh->cum_tsn_ack));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
 /* RFC 2960 9.2
  * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
  * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c
index dd4ddc4..fc143c8 100644
--- a/net/sctp/sm_statetable.c
+++ b/net/sctp/sm_statetable.c
@@ -270,7 +270,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
 	/* SCTP_STATE_SHUTDOWN_SENT */ \
 	TYPE_SCTP_FUNC(sctp_sf_do_9_2_shutdown_ack), \
 	/* SCTP_STATE_SHUTDOWN_RECEIVED */ \
-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
+	TYPE_SCTP_FUNC(sctp_sf_do_9_2_shut_ctsn), \
 	/* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
 	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 } /* TYPE_SCTP_SHUTDOWN */
-- 
1.6.0.2.530.g67faa