nat: Do not allow the amount of pending responses to grow infinitely
Limit the amount of pending DLCX responses to three times the amount
of available endpoints. Currently all MGCP messages are sent and handled
in sequence.
diff --git a/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c b/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c
index ba15618..411d500 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c
@@ -347,6 +347,21 @@
stats->trans_id = transaction;
stats->msc_endpoint = con->msc_endp;
+ /*
+ * Too many pending requests.. let's remove the first two items.
+ */
+ if (!llist_empty(&bsc->pending_dlcx) &&
+ bsc->pending_dlcx_count >= bsc->cfg->max_endpoints * 3) {
+ struct bsc_nat_call_stats *tmp;
+ LOGP(DNAT, LOGL_ERROR,
+ "Too many(%d) pending DLCX responses on BSC: %d\n",
+ bsc->pending_dlcx_count, bsc->cfg->nr);
+ bsc->pending_dlcx_count -= 1;
+ tmp = (struct bsc_nat_call_stats *) bsc->pending_dlcx.next;
+ llist_del(&tmp->entry);
+ talloc_free(tmp);
+ }
+
bsc->pending_dlcx_count += 1;
llist_add_tail(&stats->entry, &bsc->pending_dlcx);
}