tests: conntrackd: add cthelper-test infrastructure

This patch adds the automated testing infrastructure the user-space
helpers. Basically, this adds the `cthelper-test' program that can
be invoked from the command line:

 ./cthelper-test pcaps/oracle-tns-redirect.pcap tns tcp 1521

To test the helper with one PCAP file that contains traces of Oracle TNS
traffic. It also provides tweaks to test the DNAT content mangling code:

 ./cthelper-test pcaps/oracle-tns-redirect.pcap tns tcp 1521 dnat

This will also allow fuzzy testing of user-space helper, for further
validation, not yet implemented.

To compile this tool, you have to run:

./configure
make check

under the qa/cthelper-test/ directory. I'm doing like this because
this directory is not included in the standalone tarball that
make distcheck generates (I don't want to bloat it with development
tools that can be retrieved from the git repository).

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

1 files changed, 88 insertions, 0 deletions

diff --git a/tests/conntrackd/cthelper/l4_tcp.c b/tests/conntrackd/cthelper/l4_tcp.c
new file mode 100755
index 0000000..f27c85d
--- /dev/null
+++ b/tests/conntrackd/cthelper/l4_tcp.c
@@ -0,0 +1,88 @@
+#include <netinet/ip.h>
+#include <netinet/tcp.h>
+
+#include "proto.h"
+
+#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
+
+#define PRINT_CMP(...)
+
+static void l4_tcp_ct_build_tuple(const uint8_t *pkt, struct nf_conntrack *ct)
+{
+	const struct tcphdr *tcph = (const struct tcphdr *)pkt;
+
+	nfct_set_attr_u8(ct, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
+	nfct_set_attr_u8(ct, ATTR_REPL_L4PROTO, IPPROTO_TCP);
+	nfct_set_attr_u16(ct, ATTR_ORIG_PORT_SRC, tcph->source);
+	nfct_set_attr_u16(ct, ATTR_ORIG_PORT_DST, tcph->dest);
+	nfct_set_attr_u16(ct, ATTR_REPL_PORT_SRC, tcph->dest);
+	nfct_set_attr_u16(ct, ATTR_REPL_PORT_DST, tcph->source);
+}
+
+static int l4_tcp_ct_cmp_tuple_orig(const uint8_t *pkt, struct nf_conntrack *ct)
+{
+	const struct tcphdr *tcph = (const struct tcphdr *)pkt;
+
+	PRINT_CMP("cmp_orig tcph->source: %u == %u\n",
+		tcph->source, nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC));
+	PRINT_CMP("cmp_orig tcph->dest: %u == %u\n",
+		tcph->dest, nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST));
+
+	if (tcph->source == nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC) &&
+	    tcph->dest == nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST))
+		return 1;
+
+	return 0;
+}
+
+static int
+l4_tcp_ct_cmp_tuple_repl(const uint8_t *pkt, struct nf_conntrack *ct)
+{
+	const struct tcphdr *tcph = (const struct tcphdr *)pkt;
+
+	PRINT_CMP("cmp_repl tcph->source: %u == %u\n",
+		tcph->source, nfct_get_attr_u16(ct, ATTR_REPL_PORT_SRC));
+	PRINT_CMP("cmp_repl tcph->dest: %u == %u\n",
+		tcph->dest, nfct_get_attr_u16(ct, ATTR_REPL_PORT_DST));
+
+	if (tcph->source == nfct_get_attr_u16(ct, ATTR_REPL_PORT_SRC) &&
+	    tcph->dest == nfct_get_attr_u16(ct, ATTR_REPL_PORT_DST))
+		return 1;
+
+	return 0;
+}
+
+static int
+l4_tcp_ct_cmp_port(struct nf_conntrack *ct, uint16_t port)
+{
+	PRINT_CMP("cmp_port src: %u == %u\n",
+		port, nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC));
+	PRINT_CMP("cmp_port dst: %u == %u\n",
+		port, nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST));
+
+	if (port == nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC) ||
+	    port == nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST))
+		return 1;
+
+	return 0;
+}
+
+static int l4_tcp_pkt_no_data(const uint8_t *pkt)
+{
+	const struct tcphdr *tcph = (const struct tcphdr *)pkt;
+	return tcph->syn || tcph->fin || tcph->rst || !tcph->psh;
+}
+
+static struct cthelper_proto_l4_helper tcp = {
+	.l4protonum	= IPPROTO_TCP,
+	.l4ct_build	= l4_tcp_ct_build_tuple,
+	.l4ct_cmp_orig	= l4_tcp_ct_cmp_tuple_orig,
+	.l4ct_cmp_repl	= l4_tcp_ct_cmp_tuple_repl,
+	.l4ct_cmp_port	= l4_tcp_ct_cmp_port,
+	.l4pkt_no_data	= l4_tcp_pkt_no_data,
+};
+
+void l4_tcp_init(void)
+{
+	cthelper_proto_l4_helper_register(&tcp);
+}