3 files changed, 22 insertions, 1 deletions

diff --git a/include/net/sctp/user.h b/include/net/sctp/user.h
index be2334aaf52e..50b2431405f2 100644
--- a/include/net/sctp/user.h
+++ b/include/net/sctp/user.h
@@ -206,6 +206,7 @@ enum sctp_sinfo_flags {
         SCTP_UNORDERED = 1,  /* Send/receive message unordered. */
         SCTP_ADDR_OVER = 2,  /* Override the primary destination. */
         SCTP_ABORT=4,        /* Send an ABORT message to the peer. */
+        SCTP_SACK_IMMEDIATELY = 8,      /* SACK should be sent without delay */
         SCTP_EOF=MSG_FIN,    /* Initiate graceful shutdown process. */  
 };
 
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index acf7c4d128f7..8e4320040f05 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -263,9 +263,18 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
                 if (0 == i)
                         frag |= SCTP_DATA_FIRST_FRAG;
 
-                if ((i == (whole - 1)) && !over)
+                if ((i == (whole - 1)) && !over) {
                         frag |= SCTP_DATA_LAST_FRAG;
 
+                        /* The application requests to set the I-bit of the
+                         * last DATA chunk of a user message when providing
+                         * the user message to the SCTP implementation.
+                         */
+                        if ((sinfo->sinfo_flags & SCTP_EOF) ||
+                            (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
+                                frag |= SCTP_DATA_SACK_IMM;
+                }
+
                 chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
 
                 if (!chunk)
@@ -297,6 +306,10 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
                 else
                         frag = SCTP_DATA_LAST_FRAG;
 
+                if ((sinfo->sinfo_flags & SCTP_EOF) ||
+                    (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
+                        frag |= SCTP_DATA_SACK_IMM;
+
                 chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
 
                 if (!chunk)
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index c9f20e28521b..5732661c87d3 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -1011,6 +1011,13 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
                                 break;
 
                         case SCTP_XMIT_OK:
+                                /* The sender is in the SHUTDOWN-PENDING state,
+                                 * The sender MAY set the I-bit in the DATA
+                                 * chunk header.
+                                 */
+                                if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
+                                        chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
+
                                 break;
 
                         default: