LU-11894 lnet: check for asymmetrical route messages

[fs/lustre-release.git] / lnet / lnet / lib-move.c

diff --git a/lnet/lnet/lib-move.c b/lnet/lnet/lib-move.c
index fafb6d4..41ab43a 100644 (file)
--- a/lnet/lnet/lib-move.c
+++ b/lnet/lnet/lib-move.c
@@ -4223,6 +4223,52 @@ lnet_parse(struct lnet_ni *ni, struct lnet_hdr *hdr, lnet_nid_t from_nid,
                goto drop;
        }
 
+       if (lnet_drop_asym_route && for_me &&
+           LNET_NIDNET(src_nid) != LNET_NIDNET(from_nid)) {
+               struct lnet_net *net;
+               struct lnet_remotenet *rnet;
+               bool found = true;
+
+               /* we are dealing with a routed message,
+                * so see if route to reach src_nid goes through from_nid
+                */
+               lnet_net_lock(cpt);
+               net = lnet_get_net_locked(LNET_NIDNET(ni->ni_nid));
+               if (!net) {
+                       lnet_net_unlock(cpt);
+                       CERROR("net %s not found\n",
+                              libcfs_net2str(LNET_NIDNET(ni->ni_nid)));
+                       return -EPROTO;
+               }
+
+               rnet = lnet_find_rnet_locked(LNET_NIDNET(src_nid));
+               if (rnet) {
+                       struct lnet_peer_ni *gw = NULL;
+                       struct lnet_route *route;
+
+                       list_for_each_entry(route, &rnet->lrn_routes, lr_list) {
+                               found = false;
+                               gw = route->lr_gateway;
+                               if (gw->lpni_net != net)
+                                       continue;
+                               if (gw->lpni_nid == from_nid) {
+                                       found = true;
+                                       break;
+                               }
+                       }
+               }
+               lnet_net_unlock(cpt);
+               if (!found) {
+                       /* we would not use from_nid to route a message to
+                        * src_nid
+                        * => asymmetric routing detected but forbidden
+                        */
+                       CERROR("%s, src %s: Dropping asymmetrical route %s\n",
+                              libcfs_nid2str(from_nid),
+                              libcfs_nid2str(src_nid), lnet_msgtyp2str(type));
+                       goto drop;
+               }
+       }
 
        msg = lnet_msg_alloc();
        if (msg == NULL) {