nimble/mesh: configurable segment retransmist attempts

nimble/host/mesh/src/transport.c

@@ -52,7 +52,7 @@ BUILD_ASSERT(CONFIG_BT_MESH_ADV_BUF_COUNT >= (CONFIG_BT_MESH_TX_SEG_MAX + 3));
 #define SEQ_AUTH(iv_index, seq)     (((u64_t)iv_index) << 24 | (u64_t)seq)
 
 /* Number of retransmit attempts (after the initial transmit) per segment */
-#define SEG_RETRANSMIT_ATTEMPTS     4
+#define SEG_RETRANSMIT_ATTEMPTS     (MYNEWT_VAL(BLE_MESH_SEG_RETRANSMIT_ATTEMPTS))
 
 /* "This timer shall be set to a minimum of 200 + 50 * TTL milliseconds.".
  * We use 400 since 300 is a common send duration for standard HCI, and we

nimble/host/mesh/syscfg.yml

@@ -191,6 +191,12 @@ syscfg.defs:
             as there are outgoing segments.
         value: 3
 
+    BLE_MESH_SEG_RETRANSMIT_ATTEMPTS:
+        description: >
+            Number of retransmit attempts (after the initial transmit) per segment
+        value: 4
+        retrictions: 'BLE_MESH_SEG_RETRANSMIT_ATTEMPTS > 1'
+
     BLE_MESH_RELAY:
         description: >
             Support for acting as a Mesh Relay Node.

porting/examples/linux_blemesh/include/syscfg/syscfg.h

@@ -1021,6 +1021,10 @@
 #define MYNEWT_VAL_BLE_MESH_TX_SEG_MSG_COUNT (4)
 #endif
 
+#ifndef MYNEWT_VAL_BLE_MESH_TX_SEG_RETRANSMIT_ATTEMPTS
+#define MYNEWT_VAL_BLE_MESH_TX_SEG_RETRANSMIT_ATTEMPTS (2)
+#endif
+
 /*** net/nimble/host/services/ans */
 #ifndef MYNEWT_VAL_BLE_SVC_ANS_NEW_ALERT_CAT
 #define MYNEWT_VAL_BLE_SVC_ANS_NEW_ALERT_CAT (0)