From 73b3de01cecdd1e0af5901e9a279eb8a468ca995 Mon Sep 17 00:00:00 2001
From: Michael Braun <michael-dev@fami-braun.de>
Date: Tue, 22 Aug 2017 17:02:48 +0200
Subject: [PATCH] macsec_linux: Exit early when missing macsec kernel module

Using driver macsec_linux makes no sense without macsec kernel module
loaded.

Signed-off-by: Michael Braun <michael-dev@fami-braun.de>
---
 src/drivers/driver_macsec_linux.c | 34 +++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/src/drivers/driver_macsec_linux.c b/src/drivers/driver_macsec_linux.c
index 0694e6088..e89b3ba14 100644
--- a/src/drivers/driver_macsec_linux.c
+++ b/src/drivers/driver_macsec_linux.c
@@ -234,10 +234,44 @@ static void macsec_drv_wpa_deinit(void *priv)
 }
 
 
+static int macsec_check_macsec(void)
+{
+	struct nl_sock *sk;
+	int err = -1;
+
+	sk = nl_socket_alloc();
+	if (!sk) {
+		wpa_printf(MSG_ERROR, DRV_PREFIX "failed to alloc genl socket");
+		return -1;
+	}
+
+	if (genl_connect(sk) < 0) {
+		wpa_printf(MSG_ERROR,
+			   DRV_PREFIX "connection to genl socket failed");
+		goto out_free;
+	}
+
+	if (genl_ctrl_resolve(sk, "macsec") < 0) {
+		wpa_printf(MSG_ERROR,
+			   DRV_PREFIX "genl resolve failed - macsec kernel module not present?");
+		goto out_free;
+	}
+
+	err = 0;
+
+out_free:
+	nl_socket_free(sk);
+	return err;
+}
+
+
 static void * macsec_drv_wpa_init(void *ctx, const char *ifname)
 {
 	struct macsec_drv_data *drv;
 
+	if (macsec_check_macsec() < 0)
+		return NULL;
+
 	drv = os_zalloc(sizeof(*drv));
 	if (!drv)
 		return NULL;