diff mbox series

[ipsec-next,3/3] selftests/bpf: add xfrm_info tests

Message ID 20221128160501.769892-4-eyal.birger@gmail.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series xfrm: interface: Add unstable helpers for XFRM metadata | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-VM_Test-1 success Logs for ShellCheck
bpf/vmtest-bpf-next-VM_Test-7 success Logs for llvm-toolchain
bpf/vmtest-bpf-next-VM_Test-8 success Logs for set-matrix
bpf/vmtest-bpf-next-VM_Test-2 success Logs for build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-3 success Logs for build for aarch64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-5 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-6 success Logs for build for x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-4 success Logs for build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-9 success Logs for test_maps on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-10 success Logs for test_maps on aarch64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-12 success Logs for test_maps on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-13 success Logs for test_maps on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-14 success Logs for test_progs on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-15 success Logs for test_progs on aarch64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-17 success Logs for test_progs on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-18 success Logs for test_progs on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-19 success Logs for test_progs_no_alu32 on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-20 success Logs for test_progs_no_alu32 on aarch64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-22 success Logs for test_progs_no_alu32 on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-23 success Logs for test_progs_no_alu32 on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-24 success Logs for test_progs_no_alu32_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-25 success Logs for test_progs_no_alu32_parallel on aarch64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-26 success Logs for test_progs_no_alu32_parallel on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-27 success Logs for test_progs_no_alu32_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-28 success Logs for test_progs_no_alu32_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-29 success Logs for test_progs_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-30 success Logs for test_progs_parallel on aarch64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-32 success Logs for test_progs_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-33 success Logs for test_progs_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-34 success Logs for test_verifier on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-35 success Logs for test_verifier on aarch64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-36 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-37 success Logs for test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-38 success Logs for test_verifier on x86_64 with llvm-16
netdev/tree_selection success Guessed tree name to be net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 16 of 16 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning CHECK: Alignment should match open parenthesis WARNING: Macros with flow control statements should be avoided WARNING: Possible repeated word: 'that' WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 113 exceeds 80 columns WARNING: line length of 82 exceeds 80 columns WARNING: line length of 86 exceeds 80 columns WARNING: please, no spaces at the start of a line WARNING: quoted string split across lines
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-VM_Test-16 success Logs for test_progs on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-21 success Logs for test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-31 success Logs for test_progs_parallel on s390x with gcc
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next-VM_Test-11 success Logs for test_maps on s390x with gcc

Commit Message

Eyal Birger Nov. 28, 2022, 4:05 p.m. UTC
Test the xfrm_info kfunc helpers.

Note: the tests require support for xfrmi "external" mode in iproute2.

The test setup creates three name spaces - NS0, NS1, NS2.

XFRM tunnels are setup between NS0 and the two other NSs.

The kfunc helpers are used to steer traffic from NS0 to the other
NSs based on a userspace populated map and validate that that
return traffic had arrived from the desired NS.

Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
---
 tools/testing/selftests/bpf/config            |   2 +
 .../selftests/bpf/prog_tests/test_xfrm_info.c | 342 ++++++++++++++++++
 .../selftests/bpf/progs/test_xfrm_info_kern.c |  74 ++++
 3 files changed, 418 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 9213565c0311..9f39943d6ebd 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -20,6 +20,7 @@  CONFIG_IKCONFIG_PROC=y
 CONFIG_IMA=y
 CONFIG_IMA_READ_POLICY=y
 CONFIG_IMA_WRITE_POLICY=y
+CONFIG_INET_ESP=y
 CONFIG_IP_NF_FILTER=y
 CONFIG_IP_NF_RAW=y
 CONFIG_IP_NF_TARGET_SYNPROXY=y
@@ -71,3 +72,4 @@  CONFIG_TEST_BPF=y
 CONFIG_USERFAULTFD=y
 CONFIG_VXLAN=y
 CONFIG_XDP_SOCKETS=y
+CONFIG_XFRM_INTERFACE=y
diff --git a/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c b/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c
new file mode 100644
index 000000000000..3bd22ce6f00f
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c
@@ -0,0 +1,342 @@ 
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+
+/*
+ * Topology:
+ * ---------
+ *   NS0 namespace         |   NS1 namespace        | NS2 namespace
+ *                         |                        |
+ *   +---------------+     |   +---------------+    |
+ *   |    ipsec0     |---------|    ipsec0     |    |
+ *   | 192.168.1.100 |     |   | 192.168.1.200 |    |
+ *   | if_id: bpf    |     |   +---------------+    |
+ *   +---------------+     |                        |
+ *           |             |                        |   +---------------+
+ *           |             |                        |   |    ipsec0     |
+ *           \------------------------------------------| 192.168.1.200 |
+ *                         |                        |   +---------------+
+ *                         |                        |
+ *                         |                        | (overlay network)
+ *      ------------------------------------------------------
+ *                         |                        | (underlay network)
+ *   +--------------+      |   +--------------+     |
+ *   |    veth01    |----------|    veth10    |     |
+ *   | 172.16.1.100 |      |   | 172.16.1.200 |     |
+ *   ---------------+      |   +--------------+     |
+ *                         |                        |
+ *   +--------------+      |                        |   +--------------+
+ *   |    veth02    |-----------------------------------|    veth20    |
+ *   | 172.16.2.100 |      |                        |   | 172.16.2.200 |
+ *   +--------------+      |                        |   +--------------+
+ *
+ *
+ * Test Packet flow
+ * -----------
+ *  The tests perform 'ping 192.168.1.200' from the NS0 namespace:
+ *  1) request is routed to NS0 ipsec0
+ *  2) NS0 ipsec0 tc egress BPF program is triggered and sets the if_id based
+ *     on a map value. This makes the ipsec0 device in external mode select the
+ *     destination tunnel
+ *  3) ping reaches the other namespace (NS1 or NS2 based on which if_id was
+ *     used) and response is sent
+ *  4) response is received on NS0 ipsec0, tc ingress program is triggered and
+ *     records the response if_id in the map
+ *  5) requested if_id is compared with received if_id
+ */
+
+#include <net/if.h>
+
+#include "test_progs.h"
+#include "network_helpers.h"
+#include "test_xfrm_info_kern.skel.h"
+
+#define NS0 "xfrm_test_ns0"
+#define NS1 "xfrm_test_ns1"
+#define NS2 "xfrm_test_ns2"
+
+#define IF_ID_0_TO_1 1
+#define IF_ID_0_TO_2 2
+#define IF_ID_1 3
+#define IF_ID_2 4
+
+#define IP4_ADDR_VETH01 "172.16.1.100"
+#define IP4_ADDR_VETH10 "172.16.1.200"
+#define IP4_ADDR_VETH02 "172.16.2.100"
+#define IP4_ADDR_VETH20 "172.16.2.200"
+
+#define ESP_DUMMY_PARAMS \
+    "proto esp aead 'rfc4106(gcm(aes))' " \
+    "0xe4d8f4b4da1df18a3510b3781496daa82488b713 128 mode tunnel "
+
+#define PING_ARGS "-i 0.01 -c 3 -w 10 -q"
+
+#define SYS(fmt, ...)						\
+	({							\
+		char cmd[1024];					\
+		snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__);	\
+		if (!ASSERT_OK(system(cmd), cmd))		\
+			goto fail;				\
+	})
+
+#define SYS_NOFAIL(fmt, ...)					\
+	({							\
+		char cmd[1024];					\
+		snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__);	\
+		system(cmd);					\
+	})
+
+static int attach_tc_prog(struct bpf_tc_hook *hook, int igr_fd, int egr_fd)
+{
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts1, .handle = 1,
+			    .priority = 1, .prog_fd = igr_fd);
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts2, .handle = 1,
+			    .priority = 1, .prog_fd = egr_fd);
+	int ret;
+
+	ret = bpf_tc_hook_create(hook);
+	if (!ASSERT_OK(ret, "create tc hook"))
+		return ret;
+
+	if (igr_fd >= 0) {
+		hook->attach_point = BPF_TC_INGRESS;
+		ret = bpf_tc_attach(hook, &opts1);
+		if (!ASSERT_OK(ret, "bpf_tc_attach")) {
+			bpf_tc_hook_destroy(hook);
+			return ret;
+		}
+	}
+
+	if (egr_fd >= 0) {
+		hook->attach_point = BPF_TC_EGRESS;
+		ret = bpf_tc_attach(hook, &opts2);
+		if (!ASSERT_OK(ret, "bpf_tc_attach")) {
+			bpf_tc_hook_destroy(hook);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void cleanup(void)
+{
+	SYS_NOFAIL("test -f /var/run/netns/" NS0 " && ip netns delete " NS0);
+	SYS_NOFAIL("test -f /var/run/netns/" NS1 " && ip netns delete " NS1);
+	SYS_NOFAIL("test -f /var/run/netns/" NS2 " && ip netns delete " NS2);
+}
+
+static int config_underlay(void)
+{
+	SYS("ip netns add " NS0);
+	SYS("ip netns add " NS1);
+	SYS("ip netns add " NS2);
+
+	/* NS0 <-> NS1 [veth01 <-> veth10] */
+	SYS("ip link add veth01 netns " NS0 " type veth peer name veth10 netns " NS1);
+	SYS("ip -net " NS0 " addr add " IP4_ADDR_VETH01 "/24 dev veth01");
+	SYS("ip -net " NS0 " link set dev veth01 up");
+	SYS("ip -net " NS1 " addr add " IP4_ADDR_VETH10 "/24 dev veth10");
+	SYS("ip -net " NS1 " link set dev veth10 up");
+
+	/* NS0 <-> NS2 [veth02 <-> veth20] */
+	SYS("ip link add veth02 netns " NS0 " type veth peer name veth20 netns " NS2);
+	SYS("ip -net " NS0 " addr add " IP4_ADDR_VETH02 "/24 dev veth02");
+	SYS("ip -net " NS0 " link set dev veth02 up");
+	SYS("ip -net " NS2 " addr add " IP4_ADDR_VETH20 "/24 dev veth20");
+	SYS("ip -net " NS2 " link set dev veth20 up");
+
+	return 0;
+fail:
+	return -1;
+}
+
+static int setup_xfrm_tunnel_ns(const char *ns, const char *ipv4_local,
+				const char *ipv4_remote, int if_id)
+{
+	/* State: local -> remote */
+	SYS("ip -net %s xfrm state add src %s dst %s spi 1 "
+	    ESP_DUMMY_PARAMS "if_id %d", ns, ipv4_local, ipv4_remote, if_id);
+
+	/* State: local <- remote */
+	SYS("ip -net %s xfrm state add src %s dst %s spi 1 "
+	    ESP_DUMMY_PARAMS "if_id %d", ns, ipv4_remote, ipv4_local, if_id);
+
+	/* Policy: local -> remote */
+	SYS("ip -net %s xfrm policy add dir out src 0.0.0.0/0 dst 0.0.0.0/0 "
+	    "if_id %d tmpl src %s dst %s proto esp mode tunnel if_id %d", ns,
+	    if_id, ipv4_local, ipv4_remote, if_id);
+
+	/* Policy: local <- remote */
+	SYS("ip -net %s xfrm policy add dir in src 0.0.0.0/0 dst 0.0.0.0/0 "
+	    "if_id %d tmpl src %s dst %s proto esp mode tunnel if_id %d", ns,
+	    if_id, ipv4_remote, ipv4_local, if_id);
+
+	return 0;
+fail:
+	return -1;
+}
+
+static int setup_xfrm_tunnel(const char *ns_a, const char *ns_b,
+			     const char *ipv4_a, const char *ipv4_b,
+			     int if_id_a, int if_id_b)
+{
+	return setup_xfrm_tunnel_ns(ns_a, ipv4_a, ipv4_b, if_id_a) ||
+		setup_xfrm_tunnel_ns(ns_b, ipv4_b, ipv4_a, if_id_b);
+}
+
+static int config_overlay(void)
+{
+	if (setup_xfrm_tunnel(NS0, NS1, IP4_ADDR_VETH01, IP4_ADDR_VETH10,
+			      IF_ID_0_TO_1, IF_ID_1))
+		goto fail;
+	if (setup_xfrm_tunnel(NS0, NS2, IP4_ADDR_VETH02, IP4_ADDR_VETH20,
+			      IF_ID_0_TO_2, IF_ID_2))
+		goto fail;
+
+	SYS("ip -net " NS0 " link add ipsec0 type xfrm external");
+	SYS("ip -net " NS0 " addr add 192.168.1.100/24 dev ipsec0");
+	SYS("ip -net " NS0 " link set dev ipsec0 up");
+
+	SYS("ip -net " NS1 " link add ipsec0 type xfrm if_id %d", IF_ID_1);
+	SYS("ip -net " NS1 " addr add 192.168.1.200/24 dev ipsec0");
+	SYS("ip -net " NS1 " link set dev ipsec0 up");
+
+	SYS("ip -net " NS2 " link add ipsec0 type xfrm if_id %d", IF_ID_2);
+	SYS("ip -net " NS2 " addr add 192.168.1.200/24 dev ipsec0");
+	SYS("ip -net " NS2 " link set dev ipsec0 up");
+
+	return 0;
+fail:
+	return -1;
+}
+
+static int test_ping(int family, const char *addr)
+{
+	SYS("%s %s %s > /dev/null", ping_command(family), PING_ARGS, addr);
+	return 0;
+fail:
+	return -1;
+}
+
+static int test_xfrm_ping(int dst_if_id_map_fd, u32 if_id)
+{
+	u32 dst_if_id;
+	int key, err;
+
+	key = 0;
+	dst_if_id = if_id;
+	err = bpf_map_update_elem(dst_if_id_map_fd, &key, &dst_if_id, BPF_ANY);
+	if (!ASSERT_OK(err, "update bpf dst_if_id_map"))
+		return -1;
+
+	if (test_ping(AF_INET, "192.168.1.200"))
+		return -1;
+
+	key = 1;
+	dst_if_id = 0;
+	err = bpf_map_lookup_elem(dst_if_id_map_fd, &key, &dst_if_id);
+	if (!ASSERT_OK(err, "lookup bpf dst_if_id_map"))
+		return -1;
+
+	if (!ASSERT_EQ(dst_if_id, if_id, "if_id"))
+		return -1;
+
+	return 0;
+}
+
+static void test_xfrm_info(void)
+{
+	int get_xfrm_info_prog_fd, set_xfrm_info_prog_fd;
+	struct test_xfrm_info_kern *skel = NULL;
+	struct nstoken *nstoken = NULL;
+	int dst_if_id_map_fd = -1;
+	int ifindex = -1;
+	DECLARE_LIBBPF_OPTS(bpf_tc_hook, tc_hook,
+			    .attach_point = BPF_TC_INGRESS);
+
+	/* load and attach bpf progs to ipsec dev tc hook point */
+	skel = test_xfrm_info_kern__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_xfrm_info_kern__open_and_load"))
+		goto done;
+	nstoken = open_netns(NS0);
+	ifindex = if_nametoindex("ipsec0");
+	if (!ASSERT_NEQ(ifindex, 0, "ipsec0 ifindex"))
+		goto done;
+	tc_hook.ifindex = ifindex;
+	set_xfrm_info_prog_fd = bpf_program__fd(skel->progs.set_xfrm_info);
+	get_xfrm_info_prog_fd = bpf_program__fd(skel->progs.get_xfrm_info);
+	if (!ASSERT_GE(set_xfrm_info_prog_fd, 0, "bpf_program__fd"))
+		goto done;
+	if (!ASSERT_GE(get_xfrm_info_prog_fd, 0, "bpf_program__fd"))
+		goto done;
+	if (attach_tc_prog(&tc_hook, get_xfrm_info_prog_fd,
+	    set_xfrm_info_prog_fd))
+		goto done;
+	dst_if_id_map_fd = bpf_map__fd(skel->maps.dst_if_id_map);
+	if (!ASSERT_GE(dst_if_id_map_fd, 0, "bpf_map__fd"))
+		goto done;
+
+	if (!ASSERT_EQ(test_xfrm_ping(dst_if_id_map_fd, IF_ID_0_TO_1), 0,
+		       "ping " NS1))
+		goto done;
+	if (!ASSERT_EQ(test_xfrm_ping(dst_if_id_map_fd, IF_ID_0_TO_2), 0,
+		       "ping " NS2))
+		goto done;
+
+done:
+	if (nstoken)
+		close_netns(nstoken);
+	if (dst_if_id_map_fd >= 0)
+		close(dst_if_id_map_fd);
+	if (skel)
+		test_xfrm_info_kern__destroy(skel);
+}
+
+#define RUN_TEST(name)							\
+	({								\
+		if (test__start_subtest(#name)) {			\
+			test_ ## name();				\
+		}							\
+	})
+
+static void *test_xfrm_info_run_tests(void *arg)
+{
+	cleanup();
+
+	config_underlay();
+	config_overlay();
+
+	RUN_TEST(xfrm_info);
+
+	cleanup();
+
+	return NULL;
+}
+
+static int probe_iproute2(void)
+{
+	if (SYS_NOFAIL("ip link add type xfrm help 2>&1 | "
+		       "grep external > /dev/null")) {
+		fprintf(stdout, "%s:SKIP: iproute2 with xfrm external support needed for this test\n", __func__);
+		return -1;
+	}
+	return 0;
+}
+
+void serial_test_xfrm_info(void)
+{
+	pthread_t test_thread;
+	int err;
+
+	if (probe_iproute2()) {
+		test__skip();
+		return;
+	}
+
+	/* Run the tests in their own thread to isolate the namespace changes
+	 * so they do not affect the environment of other tests.
+	 * (specifically needed because of unshare(CLONE_NEWNS) in open_netns())
+	 */
+	err = pthread_create(&test_thread, NULL, &test_xfrm_info_run_tests, NULL);
+	if (ASSERT_OK(err, "pthread_create"))
+		ASSERT_OK(pthread_join(test_thread, NULL), "pthread_join");
+}
diff --git a/tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c b/tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c
new file mode 100644
index 000000000000..98991a83c1e9
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c
@@ -0,0 +1,74 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <linux/pkt_cls.h>
+#include <bpf/bpf_helpers.h>
+
+#define log_err(__ret) bpf_printk("ERROR line:%d ret:%d\n", __LINE__, __ret)
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 2);
+	__type(key, __u32);
+	__type(value, __u32);
+} dst_if_id_map SEC(".maps");
+
+struct bpf_xfrm_info {
+	__u32 if_id;
+	int link;
+};
+
+int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx,
+			  const struct bpf_xfrm_info *from) __ksym;
+int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx,
+			  struct bpf_xfrm_info *to) __ksym;
+
+SEC("tc")
+int set_xfrm_info(struct __sk_buff *skb)
+{
+	struct bpf_xfrm_info info = {};
+	__u32 *if_id = NULL;
+	__u32 index = 0;
+	int ret = -1;
+
+	if_id = bpf_map_lookup_elem(&dst_if_id_map, &index);
+	if (!if_id) {
+		log_err(ret);
+		return TC_ACT_SHOT;
+	}
+
+	info.if_id = *if_id;
+	ret = bpf_skb_set_xfrm_info(skb, &info);
+	if (ret < 0) {
+		log_err(ret);
+		return TC_ACT_SHOT;
+	}
+
+	return TC_ACT_UNSPEC;
+}
+
+SEC("tc")
+int get_xfrm_info(struct __sk_buff *skb)
+{
+	struct bpf_xfrm_info info = {};
+	__u32 *if_id = NULL;
+	__u32 index = 1;
+	int ret = -1;
+
+	if_id = bpf_map_lookup_elem(&dst_if_id_map, &index);
+	if (!if_id) {
+		log_err(ret);
+		return TC_ACT_SHOT;
+	}
+
+	ret = bpf_skb_get_xfrm_info(skb, &info);
+	if (ret < 0) {
+		log_err(ret);
+		return TC_ACT_SHOT;
+	}
+
+	*if_id = info.if_id;
+
+	return TC_ACT_UNSPEC;
+}
+
+char _license[] SEC("license") = "GPL";