af-alg: Silently skip probing algorithms if AF_ALG is not supported

If the af-alg plugin is enabled, but kernel support is missing, we get
an error line during startup for each probed algorithm. This is way too
verbose, so just skip probing if AF_ALG is unsupported.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/libstrongswan/plugins/af_alg/af_alg_plugin.c b/src/libstrongswan/plugins/af_alg/af_alg_plugin.c
index 445667507..571882cec 100644
--- a/src/libstrongswan/plugins/af_alg/af_alg_plugin.c
+++ b/src/libstrongswan/plugins/af_alg/af_alg_plugin.c
@@ -22,6 +22,8 @@
 #include "af_alg_prf.h"
 #include "af_alg_crypter.h"
 
+#include <unistd.h>
+
 typedef struct private_af_alg_plugin_t private_af_alg_plugin_t;
 
 /**
@@ -41,6 +43,19 @@ METHOD(plugin_t, get_name, char*,
 	return "af-alg";
 }
 
+static bool af_alg_supported()
+{
+	int fd;
+
+	fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
+	if (fd != -1)
+	{
+		close(fd);
+		return true;
+	}
+	return false;
+}
+
 METHOD(plugin_t, get_features, int,
 	private_af_alg_plugin_t *this, plugin_feature_t *features[])
 {
@@ -50,6 +65,10 @@ METHOD(plugin_t, get_features, int,
 
 	if (!count)
 	{	/* initialize only once */
+		if (!af_alg_supported())
+		{
+			return 0;
+		}
 		f[count++] = PLUGIN_REGISTER(HASHER, af_alg_hasher_create);
 		af_alg_hasher_probe(f, &count);
 		f[count++] = PLUGIN_REGISTER(SIGNER, af_alg_signer_create);