bgpd: Do not send UPDATE message with maximum-prefix

When using maximum-prefix and count is overflow BGP
sends UPDATE message:

Apr 15 20:45:06 exit1-debian-9 bgpd[9818]: 192.168.0.2 [Error] Error parsing NLRI
Apr 15 20:45:06 exit1-debian-9 bgpd[9818]: %NOTIFICATION: sent to neighbor 192.168.0.2 3/10 (UPDATE Message Error/Invalid Network Field) 0 bytes

Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>

13 files changed, 199 insertions, 40 deletions

diff --git a/bgpd/bgp_evpn.c b/bgpd/bgp_evpn.c
index 732cc6d2b..b8f30af38 100644
--- a/bgpd/bgp_evpn.c
+++ b/bgpd/bgp_evpn.c
@@ -4862,7 +4862,7 @@ int bgp_nlri_parse_evpn(struct peer *peer, struct attr *attr,
 		if (addpath_encoded) {
 			/* When packet overflow occurs return immediately. */
 			if (pnt + BGP_ADDPATH_ID_LEN > lim)
-				return -1;
+				return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 
 			addpath_id = ntohl(*((uint32_t *)pnt));
 			pnt += BGP_ADDPATH_ID_LEN;
@@ -4870,14 +4870,14 @@ int bgp_nlri_parse_evpn(struct peer *peer, struct attr *attr,
 
 		/* All EVPN NLRI types start with type and length. */
 		if (pnt + 2 > lim)
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_EVPN_MISSING_TYPE;
 
 		rtype = *pnt++;
 		psize = *pnt++;
 
 		/* When packet overflow occur return immediately. */
 		if (pnt + psize > lim)
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 
 		switch (rtype) {
 		case BGP_EVPN_MAC_IP_ROUTE:
@@ -4888,7 +4888,7 @@ int bgp_nlri_parse_evpn(struct peer *peer, struct attr *attr,
 					EC_BGP_EVPN_FAIL,
 					"%u:%s - Error in processing EVPN type-2 NLRI size %d",
 					peer->bgp->vrf_id, peer->host, psize);
-				return -1;
+				return BGP_NLRI_PARSE_ERROR_EVPN_TYPE2_SIZE;
 			}
 			break;
 
@@ -4900,7 +4900,7 @@ int bgp_nlri_parse_evpn(struct peer *peer, struct attr *attr,
 					EC_BGP_PKT_PROCESS,
 					"%u:%s - Error in processing EVPN type-3 NLRI size %d",
 					peer->bgp->vrf_id, peer->host, psize);
-				return -1;
+				return BGP_NLRI_PARSE_ERROR_EVPN_TYPE3_SIZE;
 			}
 			break;
 
@@ -4912,7 +4912,7 @@ int bgp_nlri_parse_evpn(struct peer *peer, struct attr *attr,
 					EC_BGP_PKT_PROCESS,
 					"%u:%s - Error in processing EVPN type-4 NLRI size %d",
 					peer->bgp->vrf_id, peer->host, psize);
-				return -1;
+				return BGP_NLRI_PARSE_ERROR_EVPN_TYPE4_SIZE;
 			}
 			break;
 
@@ -4924,7 +4924,7 @@ int bgp_nlri_parse_evpn(struct peer *peer, struct attr *attr,
 					EC_BGP_PKT_PROCESS,
 					"%u:%s - Error in processing EVPN type-5 NLRI size %d",
 					peer->bgp->vrf_id, peer->host, psize);
-				return -1;
+				return BGP_NLRI_PARSE_ERROR_EVPN_TYPE5_SIZE;
 			}
 			break;
 
@@ -4935,9 +4935,9 @@ int bgp_nlri_parse_evpn(struct peer *peer, struct attr *attr,
 
 	/* Packet length consistency check. */
 	if (pnt != lim)
-		return -1;
+		return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH;
 
-	return 0;
+	return BGP_NLRI_PARSE_OK;
 }
 
 /*
diff --git a/bgpd/bgp_flowspec.c b/bgpd/bgp_flowspec.c
index ab8bfcb77..955463873 100644
--- a/bgpd/bgp_flowspec.c
+++ b/bgpd/bgp_flowspec.c
@@ -105,14 +105,14 @@ int bgp_nlri_parse_flowspec(struct peer *peer, struct attr *attr,
 
 	if (afi == AFI_IP6) {
 		flog_err(EC_LIB_DEVELOPMENT, "BGP flowspec IPv6 not supported");
-		return -1;
+		return BGP_NLRI_PARSE_ERROR_FLOWSPEC_IPV6_NOT_SUPPORTED;
 	}
 
 	if (packet->length >= FLOWSPEC_NLRI_SIZELIMIT) {
 		flog_err(EC_BGP_FLOWSPEC_PACKET,
 			 "BGP flowspec nlri length maximum reached (%u)",
 			 packet->length);
-		return -1;
+		return BGP_NLRI_PARSE_ERROR_FLOWSPEC_NLRI_SIZELIMIT;
 	}
 
 	for (; pnt < lim; pnt += psize) {
@@ -121,7 +121,7 @@ int bgp_nlri_parse_flowspec(struct peer *peer, struct attr *attr,
 
 		/* All FlowSpec NLRI begin with length. */
 		if (pnt + 1 > lim)
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 
 		psize = *pnt++;
 
@@ -131,13 +131,13 @@ int bgp_nlri_parse_flowspec(struct peer *peer, struct attr *attr,
 				EC_BGP_FLOWSPEC_PACKET,
 				"Flowspec NLRI length inconsistent ( size %u seen)",
 				psize);
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 		}
 		if (bgp_fs_nlri_validate(pnt, psize) < 0) {
 			flog_err(
 				EC_BGP_FLOWSPEC_PACKET,
 				"Bad flowspec format or NLRI options not supported");
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_FLOWSPEC_BAD_FORMAT;
 		}
 		p.family = AF_FLOWSPEC;
 		p.prefixlen = 0;
@@ -192,8 +192,8 @@ int bgp_nlri_parse_flowspec(struct peer *peer, struct attr *attr,
 			flog_err(EC_BGP_FLOWSPEC_INSTALLATION,
 				 "Flowspec NLRI failed to be %s.",
 				 attr ? "added" : "withdrawn");
-			return -1;
+			return BGP_NLRI_PARSE_ERROR;
 		}
 	}
-	return 0;
+	return BGP_NLRI_PARSE_OK;
 }
diff --git a/bgpd/bgp_label.c b/bgpd/bgp_label.c
index a219c407d..951165084 100644
--- a/bgpd/bgp_label.c
+++ b/bgpd/bgp_label.c
@@ -355,7 +355,7 @@ int bgp_nlri_parse_label(struct peer *peer, struct attr *attr,
 
 			/* When packet overflow occurs return immediately. */
 			if (pnt + BGP_ADDPATH_ID_LEN > lim)
-				return -1;
+				return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 
 			addpath_id = ntohl(*((uint32_t *)pnt));
 			pnt += BGP_ADDPATH_ID_LEN;
@@ -372,7 +372,7 @@ int bgp_nlri_parse_label(struct peer *peer, struct attr *attr,
 				EC_BGP_UPDATE_RCV,
 				"%s [Error] Update packet error / L-U (prefix length %d exceeds packet size %u)",
 				peer->host, prefixlen, (uint)(lim - pnt));
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 		}
 
 		/* Fill in the labels */
@@ -387,12 +387,12 @@ int bgp_nlri_parse_label(struct peer *peer, struct attr *attr,
 				 peer->host, prefixlen);
 			bgp_notify_send(peer, BGP_NOTIFY_UPDATE_ERR,
 					BGP_NOTIFY_UPDATE_INVAL_NETWORK);
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_LABEL_LENGTH;
 		}
 
 		if ((afi == AFI_IP && p.prefixlen > 32)
 		    || (afi == AFI_IP6 && p.prefixlen > 128))
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PREFIX_LENGTH;
 
 		/* Fetch prefix from NLRI packet */
 		memcpy(&p.u.prefix, pnt + llen, psize - llen);
@@ -463,8 +463,8 @@ int bgp_nlri_parse_label(struct peer *peer, struct attr *attr,
 			EC_BGP_UPDATE_RCV,
 			"%s [Error] Update packet error / L-U (%zu data remaining after parsing)",
 			peer->host, lim - pnt);
-		return -1;
+		return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH;
 	}
 
-	return 0;
+	return BGP_NLRI_PARSE_OK;
 }
diff --git a/bgpd/bgp_mplsvpn.c b/bgpd/bgp_mplsvpn.c
index 4c4659ad5..d7cb84c32 100644
--- a/bgpd/bgp_mplsvpn.c
+++ b/bgpd/bgp_mplsvpn.c
@@ -140,7 +140,7 @@ int bgp_nlri_parse_vpn(struct peer *peer, struct attr *attr,
 
 			/* When packet overflow occurs return immediately. */
 			if (pnt + BGP_ADDPATH_ID_LEN > lim)
-				return -1;
+				return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 
 			addpath_id = ntohl(*((uint32_t *)pnt));
 			pnt += BGP_ADDPATH_ID_LEN;
@@ -156,7 +156,7 @@ int bgp_nlri_parse_vpn(struct peer *peer, struct attr *attr,
 				EC_BGP_UPDATE_RCV,
 				"%s [Error] Update packet error / VPN (prefix length %d less than VPN min length)",
 				peer->host, prefixlen);
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PREFIX_LENGTH;
 		}
 
 		/* sanity check against packet data */
@@ -165,7 +165,7 @@ int bgp_nlri_parse_vpn(struct peer *peer, struct attr *attr,
 				EC_BGP_UPDATE_RCV,
 				"%s [Error] Update packet error / VPN (prefix length %d exceeds packet size %u)",
 				peer->host, prefixlen, (uint)(lim - pnt));
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 		}
 
 		/* sanity check against storage for the IP address portion */
@@ -176,7 +176,7 @@ int bgp_nlri_parse_vpn(struct peer *peer, struct attr *attr,
 				peer->host,
 				prefixlen - VPN_PREFIXLEN_MIN_BYTES * 8,
 				sizeof(p.u));
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH;
 		}
 
 		/* Sanity check against max bitlen of the address family */
@@ -187,7 +187,7 @@ int bgp_nlri_parse_vpn(struct peer *peer, struct attr *attr,
 				peer->host,
 				prefixlen - VPN_PREFIXLEN_MIN_BYTES * 8,
 				p.family, prefix_blen(&p));
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH;
 		}
 
 		/* Copy label to prefix. */
@@ -245,7 +245,7 @@ int bgp_nlri_parse_vpn(struct peer *peer, struct attr *attr,
 			EC_BGP_UPDATE_RCV,
 			"%s [Error] Update packet error / VPN (%zu data remaining after parsing)",
 			peer->host, lim - pnt);
-		return -1;
+		return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH;
 	}
 
 	return 0;
diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c
index 7b76d7e83..130e06a6c 100644
--- a/bgpd/bgp_packet.c
+++ b/bgpd/bgp_packet.c
@@ -308,7 +308,7 @@ int bgp_nlri_parse(struct peer *peer, struct attr *attr,
 	case SAFI_FLOWSPEC:
 		return bgp_nlri_parse_flowspec(peer, attr, packet, mp_withdraw);
 	}
-	return -1;
+	return BGP_NLRI_PARSE_ERROR;
 }
 
 /*
@@ -1568,10 +1568,11 @@ static int bgp_update_receive(struct peer *peer, bgp_size_t size)
 			nlri_ret = bgp_nlri_parse(peer, &attr, &nlris[i], 1);
 			break;
 		default:
-			nlri_ret = -1;
+			nlri_ret = BGP_NLRI_PARSE_ERROR;
 		}
 
-		if (nlri_ret < 0) {
+		if (nlri_ret < BGP_NLRI_PARSE_OK
+		    && nlri_ret != BGP_NLRI_PARSE_ERROR_PREFIX_OVERFLOW) {
 			flog_err(EC_BGP_UPDATE_RCV,
 				 "%s [Error] Error parsing NLRI", peer->host);
 			if (peer->status == Established)
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index 7036ededa..f8b8cfc08 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -4333,7 +4333,7 @@ int bgp_nlri_parse_ip(struct peer *peer, struct attr *attr,
 
 			/* When packet overflow occurs return immediately. */
 			if (pnt + BGP_ADDPATH_ID_LEN > lim)
-				return -1;
+				return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 
 			addpath_id = ntohl(*((uint32_t *)pnt));
 			pnt += BGP_ADDPATH_ID_LEN;
@@ -4351,7 +4351,7 @@ int bgp_nlri_parse_ip(struct peer *peer, struct attr *attr,
 				EC_BGP_UPDATE_RCV,
 				"%s [Error] Update packet error (wrong prefix length %d for afi %u)",
 				peer->host, p.prefixlen, packet->afi);
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PREFIX_LENGTH;
 		}
 
 		/* Packet size overflow check. */
@@ -4363,7 +4363,7 @@ int bgp_nlri_parse_ip(struct peer *peer, struct attr *attr,
 				EC_BGP_UPDATE_RCV,
 				"%s [Error] Update packet error (prefix length %d overflows packet)",
 				peer->host, p.prefixlen);
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
 		}
 
 		/* Defensive coding, double-check the psize fits in a struct
@@ -4373,7 +4373,7 @@ int bgp_nlri_parse_ip(struct peer *peer, struct attr *attr,
 				EC_BGP_UPDATE_RCV,
 				"%s [Error] Update packet error (prefix length %d too large for prefix storage %zu)",
 				peer->host, p.prefixlen, sizeof(p.u));
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH;
 		}
 
 		/* Fetch prefix from NLRI packet. */
@@ -4438,10 +4438,14 @@ int bgp_nlri_parse_ip(struct peer *peer, struct attr *attr,
 					   BGP_ROUTE_NORMAL, NULL, NULL, 0,
 					   NULL);
 
-		/* Address family configuration mismatch or maximum-prefix count
-		   overflow. */
+		/* Do not send BGP notification twice when maximum-prefix count
+		 * overflow. */
+		if (CHECK_FLAG(peer->sflags, PEER_STATUS_PREFIX_OVERFLOW))
+			return BGP_NLRI_PARSE_ERROR_PREFIX_OVERFLOW;
+
+		/* Address family configuration mismatch. */
 		if (ret < 0)
-			return -1;
+			return BGP_NLRI_PARSE_ERROR_ADDRESS_FAMILY;
 	}
 
 	/* Packet length consistency check. */
@@ -4450,10 +4454,10 @@ int bgp_nlri_parse_ip(struct peer *peer, struct attr *attr,
 			EC_BGP_UPDATE_RCV,
 			"%s [Error] Update packet error (prefix length mismatch with total length)",
 			peer->host);
-		return -1;
+		return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH;
 	}
 
-	return 0;
+	return BGP_NLRI_PARSE_OK;
 }
 
 static struct bgp_static *bgp_static_new(void)
diff --git a/bgpd/bgp_route.h b/bgpd/bgp_route.h
index a559a6b58..7bbc14b46 100644
--- a/bgpd/bgp_route.h
+++ b/bgpd/bgp_route.h
@@ -73,6 +73,24 @@ enum bgp_show_adj_route_type {
  */
 #define BGP_MAX_LABELS 2
 
+/* Error codes for handling NLRI */
+#define BGP_NLRI_PARSE_OK 0
+#define BGP_NLRI_PARSE_ERROR_PREFIX_OVERFLOW -1
+#define BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW -2
+#define BGP_NLRI_PARSE_ERROR_PREFIX_LENGTH -3
+#define BGP_NLRI_PARSE_ERROR_PACKET_LENGTH -4
+#define BGP_NLRI_PARSE_ERROR_LABEL_LENGTH -5
+#define BGP_NLRI_PARSE_ERROR_EVPN_MISSING_TYPE -6
+#define BGP_NLRI_PARSE_ERROR_EVPN_TYPE2_SIZE -7
+#define BGP_NLRI_PARSE_ERROR_EVPN_TYPE3_SIZE -8
+#define BGP_NLRI_PARSE_ERROR_EVPN_TYPE4_SIZE -9
+#define BGP_NLRI_PARSE_ERROR_EVPN_TYPE5_SIZE -10
+#define BGP_NLRI_PARSE_ERROR_FLOWSPEC_IPV6_NOT_SUPPORTED -11
+#define BGP_NLRI_PARSE_ERROR_FLOWSPEC_NLRI_SIZELIMIT -12
+#define BGP_NLRI_PARSE_ERROR_FLOWSPEC_BAD_FORMAT -13
+#define BGP_NLRI_PARSE_ERROR_ADDRESS_FAMILY -14
+#define BGP_NLRI_PARSE_ERROR -32
+
 /* Ancillary information to struct bgp_path_info,
  * used for uncommonly used data (aggregation, MPLS, etc.)
  * and lazily allocated to save memory.
diff --git a/tests/topotests/bgp_maximum_prefix_invalid_update/__init__.py b/tests/topotests/bgp_maximum_prefix_invalid_update/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tests/topotests/bgp_maximum_prefix_invalid_update/__init__.py
diff --git a/tests/topotests/bgp_maximum_prefix_invalid_update/r1/bgpd.conf b/tests/topotests/bgp_maximum_prefix_invalid_update/r1/bgpd.conf
new file mode 100644
index 000000000..235b42b3d
--- /dev/null
+++ b/tests/topotests/bgp_maximum_prefix_invalid_update/r1/bgpd.conf
@@ -0,0 +1,4 @@
+router bgp 65000
+  neighbor 192.168.255.2 remote-as 65001
+  address-family ipv4 unicast
+    redistribute connected
diff --git a/tests/topotests/bgp_maximum_prefix_invalid_update/r1/zebra.conf b/tests/topotests/bgp_maximum_prefix_invalid_update/r1/zebra.conf
new file mode 100644
index 000000000..0a283c06d
--- /dev/null
+++ b/tests/topotests/bgp_maximum_prefix_invalid_update/r1/zebra.conf
@@ -0,0 +1,9 @@
+!
+interface lo
+ ip address 172.16.255.254/32
+!
+interface r1-eth0
+ ip address 192.168.255.1/24
+!
+ip forwarding
+!
diff --git a/tests/topotests/bgp_maximum_prefix_invalid_update/r2/bgpd.conf b/tests/topotests/bgp_maximum_prefix_invalid_update/r2/bgpd.conf
new file mode 100644
index 000000000..e01628415
--- /dev/null
+++ b/tests/topotests/bgp_maximum_prefix_invalid_update/r2/bgpd.conf
@@ -0,0 +1,4 @@
+router bgp 65001
+  neighbor 192.168.255.1 remote-as 65000
+  address-family ipv4
+    neighbor 192.168.255.1 maximum-prefix 1
diff --git a/tests/topotests/bgp_maximum_prefix_invalid_update/r2/zebra.conf b/tests/topotests/bgp_maximum_prefix_invalid_update/r2/zebra.conf
new file mode 100644
index 000000000..606c17bec
--- /dev/null
+++ b/tests/topotests/bgp_maximum_prefix_invalid_update/r2/zebra.conf
@@ -0,0 +1,6 @@
+!
+interface r2-eth0
+ ip address 192.168.255.2/24
+!
+ip forwarding
+!
diff --git a/tests/topotests/bgp_maximum_prefix_invalid_update/test_bgp_maximum_prefix_invalid_update.py b/tests/topotests/bgp_maximum_prefix_invalid_update/test_bgp_maximum_prefix_invalid_update.py
new file mode 100644
index 000000000..69b8c7ca5
--- /dev/null
+++ b/tests/topotests/bgp_maximum_prefix_invalid_update/test_bgp_maximum_prefix_invalid_update.py
@@ -0,0 +1,113 @@
+#!/usr/bin/env python
+
+#
+# bgp_local_as_private_remove.py
+# Part of NetDEF Topology Tests
+#
+# Copyright (c) 2019 by
+# Network Device Education Foundation, Inc. ("NetDEF")
+#
+# Permission to use, copy, modify, and/or distribute this software
+# for any purpose with or without fee is hereby granted, provided
+# that the above copyright notice and this permission notice appear
+# in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND NETDEF DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NETDEF BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY
+# DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+# WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+# OF THIS SOFTWARE.
+#
+
+"""
+bgp_maximum_prefix_invalid_update.py:
+Test if unnecesarry UPDATE message like below:
+
+[Error] Error parsing NLRI
+%NOTIFICATION: sent to neighbor X.X.X.X 3/10 (UPDATE Message Error/Invalid Network Field) 0 bytes
+
+is not sent if maximum-prefix count is overflow.
+"""
+
+import os
+import sys
+import json
+import time
+import pytest
+
+CWD = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(CWD, '../'))
+
+# pylint: disable=C0413
+from lib import topotest
+from lib.topogen import Topogen, TopoRouter, get_topogen
+from lib.topolog import logger
+from mininet.topo import Topo
+
+class TemplateTopo(Topo):
+    def build(self, *_args, **_opts):
+        tgen = get_topogen(self)
+
+        for routern in range(1, 3):
+            tgen.add_router('r{}'.format(routern))
+
+        switch = tgen.add_switch('s1')
+        switch.add_link(tgen.gears['r1'])
+        switch.add_link(tgen.gears['r2'])
+
+def setup_module(mod):
+    tgen = Topogen(TemplateTopo, mod.__name__)
+    tgen.start_topology()
+
+    router_list = tgen.routers()
+
+    for i, (rname, router) in enumerate(router_list.iteritems(), 1):
+        router.load_config(
+            TopoRouter.RD_ZEBRA,
+            os.path.join(CWD, '{}/zebra.conf'.format(rname))
+        )
+        router.load_config(
+            TopoRouter.RD_BGP,
+            os.path.join(CWD, '{}/bgpd.conf'.format(rname))
+        )
+
+    tgen.start_router()
+
+def teardown_module(mod):
+    tgen = get_topogen()
+    tgen.stop_topology()
+
+def test_bgp_maximum_prefix_invalid():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    def _bgp_converge(router):
+        while True:
+            output = json.loads(tgen.gears[router].vtysh_cmd("show ip bgp neighbor 192.168.255.1 json"))
+            if output['192.168.255.1']['connectionsEstablished'] > 3:
+                return True
+            time.sleep(1)
+
+    def _bgp_parsing_nlri(router):
+        cmd_max_exceeded = 'grep "%MAXPFXEXCEED: No. of IPv4 Unicast prefix received" bgpd.log'
+        cmdt_error_parsing_nlri = 'grep "Error parsing NLRI" bgpd.log'
+        output_max_exceeded = tgen.gears[router].run(cmd_max_exceeded)
+        output_error_parsing_nlri = tgen.gears[router].run(cmdt_error_parsing_nlri)
+
+        if len(output_max_exceeded) > 0:
+            if len(output_error_parsing_nlri) > 0:
+                return False
+        return True
+
+
+    if _bgp_converge('r2'):
+        assert _bgp_parsing_nlri('r2') == True
+
+if __name__ == '__main__':
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))