*: Modify agentx to be allowed to be called

If you had a situation where an operator turned on
ospfd with snmp but not ospf6d and agentx was configured
then you get into a situation where ospf6d would complain
that the config for agentx did not exist.  Let's modify
the code to allow this situation to happen.

Fixes: #15896
Signed-off-by: Donald Sharp <sharpd@nvidia.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/lib/libagentx.c b/lib/libagentx.c
new file mode 100644
index 0000000000..23826572ed
--- /dev/null
+++ b/lib/libagentx.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* SNMP cli support
+ * Copyright (C) 2024 Donald Sharp <sharpd@nvidia.com> NVIDIA Corporation
+ */
+#include <zebra.h>
+
+#include "lib/hook.h"
+#include "lib/libagentx.h"
+#include "command.h"
+
+DEFINE_HOOK(agentx_cli_enabled, (), ());
+DEFINE_HOOK(agentx_cli_disabled, (), ());
+
+bool agentx_enabled;
+
+/* AgentX node. */
+static int config_write_agentx(struct vty *vty)
+{
+	if (agentx_enabled)
+		vty_out(vty, "agentx\n");
+	return 1;
+}
+
+static struct cmd_node agentx_node = {
+	.name = "smux",
+	.node = SMUX_NODE,
+	.prompt = "",
+	.config_write = config_write_agentx,
+};
+
+DEFUN(agentx_enable, agentx_enable_cmd, "agentx",
+      "SNMP AgentX protocol settings\n")
+{
+	if (!hook_have_hooks(agentx_cli_enabled)) {
+		zlog_info(
+			"agentx specified but the agentx Module is not loaded, is this intentional?");
+
+		return CMD_SUCCESS;
+	}
+
+	hook_call(agentx_cli_enabled);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(no_agentx, no_agentx_cmd, "no agentx",
+      NO_STR "SNMP AgentX protocol settings\n")
+{
+	vty_out(vty, "SNMP AgentX support cannot be disabled once enabled\n");
+	if (!hook_call(agentx_cli_disabled))
+		return CMD_WARNING_CONFIG_FAILED;
+
+	return CMD_SUCCESS;
+}
+
+void libagentx_init(void)
+{
+	agentx_enabled = false;
+
+	install_node(&agentx_node);
+	install_element(CONFIG_NODE, &agentx_enable_cmd);
+	install_element(CONFIG_NODE, &no_agentx_cmd);
+}