From 99964c1054661120e9c40657582c1f99dad18ffe Mon Sep 17 00:00:00 2001
From: Andre Puschmann <andre@softwareradiosystems.com>
Date: Mon, 30 Jul 2018 14:54:49 +0200
Subject: [PATCH] fix RLC AM issue when building segements that require N_li in
 header

---
 lib/src/upper/rlc_am.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/src/upper/rlc_am.cc b/lib/src/upper/rlc_am.cc
index 71eb6fa34..92c33f652 100644
--- a/lib/src/upper/rlc_am.cc
+++ b/lib/src/upper/rlc_am.cc
@@ -663,6 +663,11 @@ int rlc_am::build_segment(uint8_t *payload, uint32_t nof_bytes, rlc_amd_retx_t r
   uint32_t pdu_space = 0;
 
   head_len = rlc_am_packed_length(&new_header);
+  if (old_header.N_li > 0) {
+    // Make sure we can fit at least one N_li element if old header contained at least one
+    head_len += 2;
+  }
+
   if(nof_bytes <= head_len)
   {
     log->warning("%s Cannot build a PDU segment - %d bytes available, %d bytes required for header\n",