bfdd: warn users about echo-mode restrictions

Echo-mode implementation is currently broken. Instead of sending packets
to it's own address, bfdd is sending echo packets to the peer's address.
It may seem to work when testing between two FRR instances, because FRR
loops back such packets, but no other implementation is supposed to do
that.

Let's warn users that the current implementation works only between two
FRR instances.

Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>

diff --git a/bfdd/bfdd_cli.c b/bfdd/bfdd_cli.c
index 206f6c7d0c1d64eb9f7dc4ed01b6c7e004816e46..211588cce12d436c2678aa5437c96c8defa3ac77 100644 (file)
--- a/bfdd/bfdd_cli.c
+++ b/bfdd/bfdd_cli.c
@@ -433,6 +433,10 @@ DEFPY_YANG(
                return CMD_WARNING_CONFIG_FAILED;
        }
 
+       if (!no && !bglobal.bg_use_dplane) {
+               vty_out(vty, "%% Current implementation of echo mode works only when the peer is also FRR.\n");
+       }
+
        nb_cli_enqueue_change(vty, "./echo-mode", NB_OP_MODIFY,
                              no ? "false" : "true");
        return nb_cli_apply_changes(vty, NULL);

diff --git a/doc/user/bfd.rst b/doc/user/bfd.rst
index b8f749b740e7b564906c90b37e09d21bc67e266b..87f560b5bb866c84f30850718d63b3f02dc3874c 100644 (file)
--- a/doc/user/bfd.rst
+++ b/doc/user/bfd.rst
@@ -174,7 +174,8 @@ BFD peers and profiles share the same BFD session configuration commands.
 .. clicmd:: echo-mode
 
    Enables or disables the echo transmission mode. This mode is disabled
-   by default.
+   by default. If you are not using distributed BFD then echo mode works
+   only when the peer is also FRR.
 
    It is recommended that the transmission interval of control packets
    to be increased after enabling echo-mode to reduce bandwidth usage.