diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c index ea79a1aa..9e275152 100644 --- a/sysdep/linux/netlink.c +++ b/sysdep/linux/netlink.c @@ -1593,8 +1593,24 @@ done: } static inline int -nl_allow_replace(struct krt_proto *p, rte *new) +nl_allow_replace(struct krt_proto *p, const rte *new, const rte *old) { + /* + * In kernel routing tables, (net, metric) is the primary key. Therefore, we + * can use NL_OP_REPLACE only if the new and and the old route have the same + * kernel metric, otherwise the replace would just add the new route while + * keep the old one. + */ + + if ((p->af != AF_MPLS) && (KRT_CF->sys.metric == 0)) + { + uint new_metric = ea_get_int(new->attrs, &ea_krt_metric, 0); + uint old_metric = ea_get_int(old->attrs, &ea_krt_metric, 0); + + if (new_metric != old_metric) + return 0; + } + /* * We use NL_OP_REPLACE for IPv4, it has an issue with not checking for * matching rtm_protocol, but that is OK when dedicated priority is used. @@ -1626,7 +1642,7 @@ krt_replace_rte(struct krt_proto *p, const net_addr *n UNUSED, rte *new, const r { int err = 0; - if (old && new && nl_allow_replace(p, new)) + if (old && new && nl_allow_replace(p, new, old)) { err = nl_send_route(p, new, NL_OP_REPLACE); }