[SCTP] Control chunk bundling.

Control chunks should be bundled (implementor's guide advises
specifically of case were ERROR should be bundled with CE to avoid
race condition.   Patch introduces a outq_cork/outq_uncork to
immediate transferral of control chunks and then release to the
packet bundling code. 

include/net/sctp/structs.h

@@ -963,11 +963,14 @@ struct sctp_outq {
 	/* How many unackd bytes do we have in-flight?  */
 	__u32 outstanding_bytes;
 
+	/* Corked? */
+	char cork;
+
 	/* Is this structure empty?  */
-	int empty;
+	char empty;
 
 	/* Are we kfree()able? */
-	int malloced;
+	char malloced;
 };
 
 struct sctp_outq *sctp_outq_new(struct sctp_association *);
@@ -985,10 +988,16 @@ int sctp_outq_set_output_handlers(struct sctp_outq *,
 				  sctp_outq_ohandler_t build,
 				  sctp_outq_ohandler_force_t force);
 void sctp_outq_restart(struct sctp_outq *);
+
 void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
 		     sctp_retransmit_reason_t);
 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
-
+int sctp_outq_uncork(struct sctp_outq *);
+/* Uncork and flush an outqueue.  */
+static inline void sctp_outq_cork(struct sctp_outq *q)
+{
+	q->cork = 1;
+}
 
 /* These bind address data fields common between endpoints and associations */
 struct sctp_bind_addr {
@@ -1393,7 +1402,6 @@ struct sctp_association {
 	/* The largest timeout or RTO value to use in attempting an INIT */
 	__u16 max_init_timeo;
 
-
 	int timeouts[SCTP_NUM_TIMEOUT_TYPES];
 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
 
@@ -1494,9 +1502,6 @@ struct sctp_association {
 	 */
 	struct sctp_ulpq ulpq;
 
-	/* Need to send an ECNE Chunk? */
-	int need_ecne;
-
 	/* Last TSN that caused an ECNE Chunk to be sent.  */
 	__u32 last_ecne_tsn;
 
@@ -1509,9 +1514,6 @@ struct sctp_association {
 	/* Number of seconds of idle time before an association is closed.  */
 	__u32 autoclose;
 
-	/* Name for debugging output... */
-	char *debug_name;
-
 	/* These are to support
 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
 	 *  and Enforcement of Flow and Message Limits"
@@ -1519,8 +1521,7 @@ struct sctp_association {
 	 * or "ADDIP" for short.
 	 */
 
-	/* Is the ADDIP extension enabled for this association? */
-	int addip_enable;
+
 
 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
 	 *
@@ -1605,8 +1606,14 @@ struct sctp_association {
 	 */
 	__u32 addip_serial;
 
+	/* Is the ADDIP extension enabled for this association? */
+	char addip_enable;
+
+	/* Need to send an ECNE Chunk? */
+	char need_ecne;
+
 	/* Is it a temporary association? */ 
-	__u8 temp;
+	char temp;
 };
 
 

net/sctp/outqueue.c

@@ -230,6 +230,7 @@ void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
 
 	q->outstanding_bytes = 0;
 	q->empty = 1;
+	q->cork  = 0;
 
 	q->malloced = 0;
 	q->out_qlen = 0;
@@ -365,6 +366,7 @@ int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
 	if (error < 0)
 		return error;
 
+	if (!q->cork)
 		error = sctp_outq_flush(q, 0);
 
 	return error;
@@ -816,8 +818,19 @@ struct sctp_chunk *sctp_fragment_chunk(struct sctp_chunk *chunk,
 	return NULL;
 }
 
+/* Cork the outqueue so queued chunks are really queued. */
+int sctp_outq_uncork(struct sctp_outq *q)
+{
+	int error = 0;
+	if (q->cork) {
+		q->cork = 0;
+		error = sctp_outq_flush(q, 0);
+	}
+	return error;
+}
+
 /*
- * sctp_outq_flush - Try to flush an outqueue.
+ * Try to flush an outqueue.
  *
  * Description: Send everything in q which we legally can, subject to
  * congestion limitations.

net/sctp/sm_sideeffect.c

@@ -844,6 +844,7 @@ int sctp_cmd_interpreter(sctp_event_t event_type, sctp_subtype_t subtype,
 	unsigned long timeout;
 	struct sctp_transport *t;
 	sctp_sackhdr_t sackh;
+	int local_cork = 0;
 
 	if (SCTP_EVENT_T_TIMEOUT != event_type)
 		chunk = (struct sctp_chunk *) event_arg;
@@ -863,6 +864,10 @@ int sctp_cmd_interpreter(sctp_event_t event_type, sctp_subtype_t subtype,
 
 		case SCTP_CMD_NEW_ASOC:
 			/* Register a new association.  */
+			if (local_cork) {
+				sctp_outq_uncork(&asoc->outqueue); 
+				local_cork = 0;
+			}
 			asoc = cmd->obj.ptr;
 			/* Register with the endpoint.  */
 			sctp_endpoint_add_asoc(ep, asoc);
@@ -878,6 +883,10 @@ int sctp_cmd_interpreter(sctp_event_t event_type, sctp_subtype_t subtype,
 		       break;
 
 		case SCTP_CMD_DELETE_TCB:			
+			if (local_cork) {
+				sctp_outq_uncork(&asoc->outqueue);
+				local_cork = 0;
+			}
 			/* Delete the current association.  */
 			sctp_cmd_delete_tcb(commands, asoc);
 			asoc = NULL;
@@ -981,9 +990,13 @@ int sctp_cmd_interpreter(sctp_event_t event_type, sctp_subtype_t subtype,
 			break;
 
 		case SCTP_CMD_REPLY:
+			/* If an caller has not already corked, do cork. */
+			if (!asoc->outqueue.cork) {
+				sctp_outq_cork(&asoc->outqueue);
+				local_cork = 1;
+			}
 			/* Send a chunk to our peer.  */
-			error = sctp_outq_tail(&asoc->outqueue,
-					       cmd->obj.ptr);
+			error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
 			break;
 
 		case SCTP_CMD_SEND_PKT:
@@ -1001,7 +1014,8 @@ int sctp_cmd_interpreter(sctp_event_t event_type, sctp_subtype_t subtype,
 
 		case SCTP_CMD_TRANSMIT:
 			/* Kick start transmission. */
-			error = sctp_outq_flush(&asoc->outqueue, 0);
+			error = sctp_outq_uncork(&asoc->outqueue);
+			local_cork = 0;
 			break;
 
 		case SCTP_CMD_ECN_CE:
@@ -1172,13 +1186,15 @@ int sctp_cmd_interpreter(sctp_event_t event_type, sctp_subtype_t subtype,
 			break;
 		};
 		if (error)
-			return error;
+			break;
 	}
 
+out:
+	if (local_cork)
+		sctp_outq_uncork(&asoc->outqueue);
 	return error;
-
 nomem:
 	error = -ENOMEM;
-	return error;
+	goto out;
 }
 

net/sctp/socket.c

@@ -891,8 +891,7 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
 	}
 
 	if (asoc) {
-		SCTP_DEBUG_PRINTK("Just looked up association: "
-				  "%s. \n", asoc->debug_name);
+		SCTP_DEBUG_PRINTK("Just looked up association: %p.\n", asoc);
 
 		/* We cannot send a message on a TCP-style SCTP_SS_ESTABLISHED
 		 * socket that has an association in CLOSED state. This can
@@ -1092,6 +1091,7 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
 		sctp_primitive_SEND(asoc, chunk);
 		SCTP_DEBUG_PRINTK("We sent primitively.\n");
 	}
+
 	sctp_datamsg_free(datamsg);
 	err = msg_len;
 

net/sctp/ulpevent.c

@@ -328,7 +328,7 @@ struct sctp_ulpevent *sctp_ulpevent_make_remote_error(
 
 	ch = (sctp_errhdr_t *)(chunk->skb->data);
 	cause = ch->cause;
-	elen = ntohs(ch->length) - sizeof(sctp_errhdr_t);
+	elen = WORD_ROUND(ntohs(ch->length)) - sizeof(sctp_errhdr_t);
 
 	/* Pull off the ERROR header.  */
 	skb_pull(chunk->skb, sizeof(sctp_errhdr_t));
@@ -336,10 +336,8 @@ struct sctp_ulpevent *sctp_ulpevent_make_remote_error(
 	/* Copy the skb to a new skb with room for us to prepend
 	 * notification with.
 	 */
-	skb = skb_copy_expand(chunk->skb,
-			      sizeof(struct sctp_remote_error), /* headroom */
-			      0,                                /* tailroom */
-			      gfp);
+	skb = skb_copy_expand(chunk->skb, sizeof(struct sctp_remote_error), 
+			      0, gfp);
 
 	/* Pull off the rest of the cause TLV from the chunk.  */
 	skb_pull(chunk->skb, elen);