filter: check if kernel-space filtering is available

Check if the Linux kernel is >= 2.6.26, otherwise it does not support
kernel-space filtering. This is not clean but we have no choice, the BSF
infrastructure does not return ENOTSUPP for unsupported operations.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
index 7360b77..a53b0a8 100644
--- a/src/main.c
+++ b/src/main.c
@@ -95,6 +95,10 @@ int main(int argc, char *argv[])
 		exit(EXIT_FAILURE);
 	}
 
+	/* BSF filter attaching does not report unsupported operations */
+	if (version >= 2 && major >= 6 && minor >= 26)
+		CONFIG(kernel_support_netlink_bsf) = 1;
+
 	for (i=1; i<argc; i++) {
 		switch(argv[i][1]) {
 		case 'd':