From 3fe846dbada52ef4b1a738340ff073514bb65a2e Mon Sep 17 00:00:00 2001
From: Simon Duquennoy <simon.duquennoy@ri.se>
Date: Mon, 26 Mar 2018 11:35:35 -0700
Subject: [PATCH] TSCH burst mode: bounded burst lengths

---
 os/net/mac/tsch/tsch-conf.h           | 13 ++++++++++---
 os/net/mac/tsch/tsch-schedule.c       |  2 +-
 os/net/mac/tsch/tsch-slot-operation.c |  1 +
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/os/net/mac/tsch/tsch-conf.h b/os/net/mac/tsch/tsch-conf.h
index 934e0884f..afd90aaef 100644
--- a/os/net/mac/tsch/tsch-conf.h
+++ b/os/net/mac/tsch/tsch-conf.h
@@ -318,10 +318,17 @@
 #endif
 
 /* Add burst mode to 6TiSCH minimal schedule */
-#ifdef TSCH_SCHEDULE_CONF_WITH_6TISCH_MINIMAL_WITH_BURST
-#define TSCH_SCHEDULE_WITH_6TISCH_MINIMAL_WITH_BURST TSCH_SCHEDULE_CONF_WITH_6TISCH_MINIMAL_WITH_BURST
+#ifdef TSCH_CONF_WITH_6TISCH_MINIMAL_WITH_BURST
+#define TSCH_WITH_6TISCH_MINIMAL_WITH_BURST TSCH_CONF_WITH_6TISCH_MINIMAL_WITH_BURST
 #else
-#define TSCH_SCHEDULE_WITH_6TISCH_MINIMAL_WITH_BURST 0
+#define TSCH_WITH_6TISCH_MINIMAL_WITH_BURST 0
+#endif
+
+/* Set an upper bound on burst length */
+#ifdef TSCH_CONF_BURST_MAX_LEN
+#define TSCH_BURST_MAX_LEN TSCH_CONF_BURST_MAX_LEN
+#else
+#define TSCH_BURST_MAX_LEN 32
 #endif
 
 /* 6TiSCH Minimal schedule slotframe length */
diff --git a/os/net/mac/tsch/tsch-schedule.c b/os/net/mac/tsch/tsch-schedule.c
index d5bf49653..a03363eb9 100644
--- a/os/net/mac/tsch/tsch-schedule.c
+++ b/os/net/mac/tsch/tsch-schedule.c
@@ -424,7 +424,7 @@ tsch_schedule_create_minimal(void)
    * Timeslot: 0, channel offset: 0. */
   tsch_schedule_add_link(sf_min,
       LINK_OPTION_RX | LINK_OPTION_TX | LINK_OPTION_SHARED | LINK_OPTION_TIME_KEEPING
-        | (TSCH_SCHEDULE_WITH_6TISCH_MINIMAL_WITH_BURST ? LINK_OPTION_BURST : 0),
+        | (TSCH_WITH_6TISCH_MINIMAL_WITH_BURST ? LINK_OPTION_BURST : 0),
       LINK_TYPE_ADVERTISING, &tsch_broadcast_address,
       0, 0);
 }
diff --git a/os/net/mac/tsch/tsch-slot-operation.c b/os/net/mac/tsch/tsch-slot-operation.c
index 6b47b4ebf..a2e9982fe 100644
--- a/os/net/mac/tsch/tsch-slot-operation.c
+++ b/os/net/mac/tsch/tsch-slot-operation.c
@@ -476,6 +476,7 @@ PT_THREAD(tsch_tx_slot(struct pt *pt, struct rtimer *t))
       /* Unicast. More packets in queue for the neighbor? */
       burst_link_requested = 0;
       if(!is_broadcast && (current_link->link_options & LINK_OPTION_BURST)
+             && tsch_current_burst_count + 1 < TSCH_BURST_MAX_LEN
              && tsch_queue_packet_count(&current_neighbor->addr) > 1) {
         burst_link_requested = 1;
         tsch_packet_set_frame_pending(packet, packet_len);