isisd: gracefully handle spf error

the code in isis_spf_add2tent was asserting in case the vertex
we were trying to add was already present in the path or tent
trees. This however CAN happen if the user accidentally configures
the system Id of the area to the same value of an estabished
neighbor. Handle this more gracefully by logging and returning,
to prevent crashes.

Signed-off-by: Emanuele Di Pascale <emanuele@voltanet.io>

1 files changed, 17 insertions, 4 deletions

diff --git a/isisd/isis_spf.c b/isisd/isis_spf.c
index daf97859f..dfcea9a92 100644
--- a/isisd/isis_spf.c
+++ b/isisd/isis_spf.c
@@ -373,12 +373,25 @@ static struct isis_vertex *isis_spf_add2tent(struct isis_spftree *spftree,
 	struct isis_vertex *vertex;
 	struct listnode *node;
 	struct isis_adjacency *parent_adj;
-#ifdef EXTREME_DEBUG
 	char buff[VID2STR_BUFFER];
-#endif
 
-	assert(isis_find_vertex(&spftree->paths, id, vtype) == NULL);
-	assert(isis_find_vertex(&spftree->tents, id, vtype) == NULL);
+	vertex = isis_find_vertex(&spftree->paths, id, vtype);
+	if (vertex != NULL) {
+		zlog_err(
+			"%s: vertex %s of type %s already in PATH; check for sysId collisions with established neighbors",
+			__func__, vid2string(vertex, buff, sizeof(buff)),
+			vtype2string(vertex->type));
+		return NULL;
+	}
+	vertex = isis_find_vertex(&spftree->tents, id, vtype);
+	if (vertex != NULL) {
+		zlog_err(
+			"%s: vertex %s of type %s already in TENT; check for sysId collisions with established neighbors",
+			__func__, vid2string(vertex, buff, sizeof(buff)),
+			vtype2string(vertex->type));
+		return NULL;
+	}
+
 	vertex = isis_vertex_new(spftree, id, vtype);
 	vertex->d_N = cost;
 	vertex->depth = depth;