sctp: implement event notification SCTP_SENDER_DRY_EVENT

This patch implement event notification SCTP_SENDER_DRY_EVENT.
SCTP Socket API Extensions:

  6.1.9. SCTP_SENDER_DRY_EVENT

  When the SCTP stack has no more user data to send or retransmit, this
  notification is given to the user. Also, at the time when a user app
  subscribes to this event, if there is no data to be sent or
  retransmit, the stack will immediately send up this notification.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 21 insertions, 0 deletions

diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index 652f09bba504..9148632b8204 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -165,6 +165,7 @@ sctp_state_fn_t sctp_sf_do_prm_requestheartbeat;
 sctp_state_fn_t sctp_sf_do_prm_asconf;
 
 /* Prototypes for other event state functions.  */
+sctp_state_fn_t sctp_sf_do_no_pending_tsn;
 sctp_state_fn_t sctp_sf_do_9_2_start_shutdown;
 sctp_state_fn_t sctp_sf_do_9_2_shutdown_ack;
 sctp_state_fn_t sctp_sf_ignore_other;
diff --git a/include/net/sctp/ulpevent.h b/include/net/sctp/ulpevent.h
index 7ea12e8e6676..99b027b2adce 100644
--- a/include/net/sctp/ulpevent.h
+++ b/include/net/sctp/ulpevent.h
@@ -132,6 +132,9 @@ struct sctp_ulpevent *sctp_ulpevent_make_authkey(
         const struct sctp_association *asoc, __u16 key_id,
         __u32 indication, gfp_t gfp);
 
+struct sctp_ulpevent *sctp_ulpevent_make_sender_dry_event(
+        const struct sctp_association *asoc, gfp_t gfp);
+
 void sctp_ulpevent_read_sndrcvinfo(const struct sctp_ulpevent *event,
         struct msghdr *);
 __u16 sctp_ulpevent_get_notification_type(const struct sctp_ulpevent *event);
diff --git a/include/net/sctp/user.h b/include/net/sctp/user.h
index 4525d8c7f71a..32fd51274037 100644
--- a/include/net/sctp/user.h
+++ b/include/net/sctp/user.h
@@ -354,6 +354,20 @@ struct sctp_authkey_event {
 
 enum { SCTP_AUTH_NEWKEY = 0, };
 
+/*
+ * 6.1.9. SCTP_SENDER_DRY_EVENT
+ *
+ * When the SCTP stack has no more user data to send or retransmit, this
+ * notification is given to the user. Also, at the time when a user app
+ * subscribes to this event, if there is no data to be sent or
+ * retransmit, the stack will immediately send up this notification.
+ */
+struct sctp_sender_dry_event {
+        __u16 sender_dry_type;
+        __u16 sender_dry_flags;
+        __u32 sender_dry_length;
+        sctp_assoc_t sender_dry_assoc_id;
+};
 
 /*
  * Described in Section 7.3
@@ -369,6 +383,7 @@ struct sctp_event_subscribe {
         __u8 sctp_partial_delivery_event;
         __u8 sctp_adaptation_layer_event;
         __u8 sctp_authentication_event;
+        __u8 sctp_sender_dry_event;
 };
 
 /*
@@ -392,6 +407,7 @@ union sctp_notification {
         struct sctp_adaptation_event sn_adaptation_event;
         struct sctp_pdapi_event sn_pdapi_event;
         struct sctp_authkey_event sn_authkey_event;
+        struct sctp_sender_dry_event sn_sender_dry_event;
 };
 
 /* Section 5.3.1
@@ -410,6 +426,7 @@ enum sctp_sn_type {
         SCTP_ADAPTATION_INDICATION,
         SCTP_AUTHENTICATION_EVENT,
 #define SCTP_AUTHENTICATION_INDICATION  SCTP_AUTHENTICATION_EVENT
+        SCTP_SENDER_DRY_EVENT,
 };
 
 /* Notification error codes used to fill up the error fields in some