From bfdde400319adc286544b0088be8bf1d40180fb7 Mon Sep 17 00:00:00 2001
From: Lorenzo Cogotti <lcg@inventati.org>
Date: Mon, 18 Oct 2021 11:45:17 +0200
Subject: [PATCH] [lonetix/bgp] Check for AGGREGATOR4 presence before checking
 its correctness

---
 lonetix/bgp/attribute.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/lonetix/bgp/attribute.c b/lonetix/bgp/attribute.c
index 1a4e934..0228cad 100644
--- a/lonetix/bgp/attribute.c
+++ b/lonetix/bgp/attribute.c
@@ -547,13 +547,15 @@ Bgpattr *Bgp_GetRealAggregator(const Bgpattrseg *tpa,
 		if (Bgp_GetErrStat(NULL))
 			return NULL;  // forward error
 
-		if (!BGP_CHKAGGRSIZ(attr4, TRUE)) {
-			Bgp_SetErrStat(BGPEBADAGGR4);
-			return NULL;
-		}
+		if (attr4) {
+			if (!BGP_CHKAGGRSIZ(attr4, TRUE)) {
+				Bgp_SetErrStat(BGPEBADAGGR4);
+				return NULL;
+			}
 
-		attr     = attr4;
-		asn32bit = TRUE;
+			attr     = attr4;
+			asn32bit = TRUE;
+		}
 	}
 
 	*isAsn32bit = asn32bit;