Merge pull request #10749 from amastbaum/routing_table_check_in_tcp

UCT/TCP: check the routing table during reachability check in TCP

Author: yosefe

src/uct/tcp/tcp_iface.c

@@ -11,6 +11,7 @@
 #include "tcp.h"
 
 #include <ucs/async/async.h>
+#include <ucs/sys/netlink.h>
 #include <ucs/sys/string.h>
 #include <ucs/config/types.h>
 #include <sys/socket.h>
@@ -201,6 +202,10 @@ uct_tcp_iface_is_reachable_v2(const uct_iface_h tl_iface,
     uct_iface_local_addr_ns_t *local_addr_ns;
     uct_tcp_device_addr_t *tcp_dev_addr;
     int is_local_loopback, is_remote_loopback;
+    struct sockaddr_storage remote_addr;
+    char remote_addr_str[UCS_SOCKADDR_STRING_LEN];
+    unsigned ndev_index;
+    ucs_status_t status;
 
     if (!uct_iface_is_reachable_params_valid(
                 params, UCT_IFACE_IS_REACHABLE_FIELD_DEVICE_ADDR)) {
@@ -236,9 +241,38 @@ uct_tcp_iface_is_reachable_v2(const uct_iface_h tl_iface,
         }
     }
 
-    /* Later connect() call can still fail if the peer is actually unreachable
-     * at UCT/TCP EP creation time */
-    return uct_iface_scope_is_reachable(tl_iface, params);
+    if ((params->field_mask & UCT_IFACE_IS_REACHABLE_FIELD_SCOPE) &&
+        (params->scope == UCT_IFACE_REACHABILITY_SCOPE_DEVICE)) {
+        return uct_iface_scope_is_reachable(tl_iface, params);
+    }
+
+    /* Check if the remote address is routable */
+    status = ucs_ifname_to_index(iface->if_name, &ndev_index);
+    if (status != UCS_OK) {
+        uct_iface_fill_info_str_buf(
+                    params, "failed to get interface index");
+        return 0;
+    }
+
+    remote_addr.ss_family = tcp_dev_addr->sa_family;
+    status = ucs_sockaddr_set_inet_addr((struct sockaddr *)&remote_addr,
+                                        tcp_dev_addr + 1);
+    if (status != UCS_OK) {
+        uct_iface_fill_info_str_buf(
+                    params, "failed to set inet address");
+        return 0;
+    }
+
+    if (!ucs_netlink_route_exists(ndev_index,
+                                  (const struct sockaddr *)&remote_addr)) {
+        uct_iface_fill_info_str_buf(
+                    params, "no route to %s",
+                    ucs_sockaddr_str((const struct sockaddr *)&remote_addr,
+                                     remote_addr_str, UCS_SOCKADDR_STRING_LEN));
+        return 0;
+    }
+
+    return 1;
 }
 
 static const char *