1 files changed, 51 insertions, 11 deletions

diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index 1748ef90950c..acf7c4d128f7 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -59,6 +59,7 @@ static void sctp_datamsg_init(struct sctp_datamsg *msg)
         msg->can_abandon = 0;
         msg->expires_at = 0;
         INIT_LIST_HEAD(&msg->chunks);
+        msg->msg_size = 0;
 }
 
 /* Allocate and initialize datamsg. */
@@ -73,6 +74,19 @@ SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
         return msg;
 }
 
+void sctp_datamsg_free(struct sctp_datamsg *msg)
+{
+        struct sctp_chunk *chunk;
+
+        /* This doesn't have to be a _safe vairant because
+         * sctp_chunk_free() only drops the refs.
+         */
+        list_for_each_entry(chunk, &msg->chunks, frag_list)
+                sctp_chunk_free(chunk);
+
+        sctp_datamsg_put(msg);
+}
+
 /* Final destructruction of datamsg memory. */
 static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
 {
@@ -142,6 +156,7 @@ static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chu
 {
         sctp_datamsg_hold(msg);
         chunk->msg = msg;
+        msg->msg_size += chunk->skb->len;
 }
 
 
@@ -158,6 +173,7 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
 {
         int max, whole, i, offset, over, err;
         int len, first_len;
+        int max_data;
         struct sctp_chunk *chunk;
         struct sctp_datamsg *msg;
         struct list_head *pos, *temp;
@@ -179,8 +195,14 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
                                   __func__, msg, msg->expires_at, jiffies);
         }
 
-        max = asoc->frag_point;
+        /* This is the biggest possible DATA chunk that can fit into
+         * the packet
+         */
+        max_data = asoc->pathmtu -
+                sctp_sk(asoc->base.sk)->pf->af->net_header_len -
+                sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk);
 
+        max = asoc->frag_point;
         /* If the the peer requested that we authenticate DATA chunks
          * we need to accound for bundling of the AUTH chunks along with
          * DATA.
@@ -189,23 +211,41 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
                 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
 
                 if (hmac_desc)
-                        max -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
+                        max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
                                             hmac_desc->hmac_len);
         }
 
+        /* Now, check if we need to reduce our max */
+        if (max > max_data)
+                max = max_data;
+
         whole = 0;
         first_len = max;
 
+        /* Check to see if we have a pending SACK and try to let it be bundled
+         * with this message.  Do this if we don't have any data queued already.
+         * To check that, look at out_qlen and retransmit list.
+         * NOTE: we will not reduce to account for SACK, if the message would
+         * not have been fragmented.
+         */
+        if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) &&
+            asoc->outqueue.out_qlen == 0 &&
+            list_empty(&asoc->outqueue.retransmit) &&
+            msg_len > max)
+                max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t));
+
         /* Encourage Cookie-ECHO bundling. */
-        if (asoc->state < SCTP_STATE_COOKIE_ECHOED) {
-                whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN);
-
-                /* Account for the DATA to be bundled with the COOKIE-ECHO. */
-                if (whole) {
-                        first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN;
-                        msg_len -= first_len;
-                        whole = 1;
-                }
+        if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
+                max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
+
+        /* Now that we adjusted completely, reset first_len */
+        if (first_len > max_data)
+                first_len = max_data;
+
+        /* Account for a different sized first fragment */
+        if (msg_len >= first_len) {
+                msg_len -= first_len;
+                whole = 1;
         }
 
         /* How many full sized?  How many bytes leftover? */