diff mbox series

[ipsec-next,v2,3/3] selftests/bpf: add xfrm_info tests

Message ID 20221129132018.985887-4-eyal.birger@gmail.com (mailing list archive)
State New
Headers show
Series xfrm: interface: Add unstable helpers for XFRM metadata | expand

Commit Message

Eyal Birger Nov. 29, 2022, 1:20 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 the
return traffic had arrived from the desired NS.

Signed-off-by: Eyal Birger <eyal.birger@gmail.com>

---

v2:
  - use an lwt route in NS1 for testing that flow as well
  - indendation fix
---
 tools/testing/selftests/bpf/config            |   2 +
 .../selftests/bpf/prog_tests/test_xfrm_info.c | 343 ++++++++++++++++++
 .../selftests/bpf/progs/test_xfrm_info_kern.c |  74 ++++
 3 files changed, 419 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

Comments

Martin KaFai Lau Nov. 30, 2022, 6:41 p.m. UTC | #1
On 11/29/22 5:20 AM, Eyal Birger wrote:
> 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 the
> return traffic had arrived from the desired NS.
> 
> Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
> 
> ---
> 
> v2:
>    - use an lwt route in NS1 for testing that flow as well
>    - indendation fix
> ---
>   tools/testing/selftests/bpf/config            |   2 +
>   .../selftests/bpf/prog_tests/test_xfrm_info.c | 343 ++++++++++++++++++
>   .../selftests/bpf/progs/test_xfrm_info_kern.c |  74 ++++
>   3 files changed, 419 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 --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..3aef72540934
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c

Nit. Just xfrm_info.c

> @@ -0,0 +1,343 @@
> +// 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 external");
> +	SYS("ip -net " NS1 " addr add 192.168.1.200/32 dev ipsec0");
> +	SYS("ip -net " NS1 " link set dev ipsec0 up");
> +	SYS("ip -net " NS1 " route add 192.168.1.100/32 dev ipsec0 encap xfrm if_id %d", IF_ID_1);
> +
> +	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();

config_*() is returning ok/err but no error checking here.  Does it make sense 
to continue if the config_*() failed?

> +
> +	RUN_TEST(xfrm_info);

nit.  Remove this macro indirection.  There is only one test.

> +
> +	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__);

Unfortunately, the BPF CI iproute2 does not have this support also :(
I am worry it will just stay SKIP for some time and rot.  Can you try to 
directly use netlink here?

https://github.com/kernel-patches/bpf/actions/runs/3578467213/jobs/6019370754#step:6:6395

> +		return -1;
> +	}
> +	return 0;
> +}
> +
> +void serial_test_xfrm_info(void)

Remove "serial_".  New test must be able to run in parallel ("./test_progs -j").

> +{
> +	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())
> +	 */

I think this comment is mostly inherited from other tests (eg. tc_redirect.c) 
but the pthread dance is actually unnecessary.  The test_progs.c will restore 
the original netns before running the next test.  I am abort to remove this from 
the tc_redirect.c also.  Please also avoid this pthread create here.

> +	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


Nit. Same here. Just xfrm_info.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)

Please try not to use unnecessary bpf_printk().  BPF CI is not capturing it also.

> +
> +struct {
> +	__uint(type, BPF_MAP_TYPE_ARRAY);
> +	__uint(max_entries, 2);
> +	__type(key, __u32);
> +	__type(value, __u32);
> +} dst_if_id_map SEC(".maps");

It is easier to use global variables instead of a map.

> +
> +struct bpf_xfrm_info {
> +	__u32 if_id;
> +	int link;
> +};

This needs __attribute__((preserve_access_index) for CO-RE.
It is easier to just include vmlinux.h to get the struct xfrm_md_info { ... }.

> +
> +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";
Martin KaFai Lau Nov. 30, 2022, 6:48 p.m. UTC | #2
On 11/30/22 10:41 AM, Martin KaFai Lau wrote:
>> +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__);
> 
> Unfortunately, the BPF CI iproute2 does not have this support also :(
> I am worry it will just stay SKIP for some time and rot.  Can you try to 
> directly use netlink here?

To be clear, I meant directly use netlink only for the xfrm link creation

> 
> https://github.com/kernel-patches/bpf/actions/runs/3578467213/jobs/6019370754#step:6:6395
Eyal Birger Dec. 1, 2022, 5:34 a.m. UTC | #3
Hi Martin,

On Wed, Nov 30, 2022 at 8:41 PM Martin KaFai Lau <martin.lau@linux.dev> wrote:
>
> On 11/29/22 5:20 AM, Eyal Birger wrote:
> > 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 the
> > return traffic had arrived from the desired NS.
> >
> > Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
> >
> > ---
> >
> > v2:
> >    - use an lwt route in NS1 for testing that flow as well
> >    - indendation fix
> > ---
> >   tools/testing/selftests/bpf/config            |   2 +
> >   .../selftests/bpf/prog_tests/test_xfrm_info.c | 343 ++++++++++++++++++
> >   .../selftests/bpf/progs/test_xfrm_info_kern.c |  74 ++++
> >   3 files changed, 419 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 --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..3aef72540934
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c
>
> Nit. Just xfrm_info.c

Ok.

>
> > @@ -0,0 +1,343 @@
> > +// 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 |
> > + *   +--------------+      |                        |   +--------------+
> > + *
> > + *
[...]
> > +
> > +#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();
>
> config_*() is returning ok/err but no error checking here.  Does it make sense
> to continue if the config_*() failed?

I'll assert their success.

>
> > +
> > +     RUN_TEST(xfrm_info);
>
> nit.  Remove this macro indirection.  There is only one test.

Ok. I was considering other possible tests in the future, but this can
be added then.

>
> > +
> > +     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__);
>
> Unfortunately, the BPF CI iproute2 does not have this support also :(
> I am worry it will just stay SKIP for some time and rot.  Can you try to
> directly use netlink here?

Yeah, I wasn't sure if adding a libmnl (or alternative) dependency
was ok here, and also didn't want to copy all that nl logic here.
So I figured it would get there eventually.

I noticed libmnl is used by the nf tests, so maybe its inclusion isn't too
bad. Unless there's a better approach.

As you noted, I should add this for the "external" support. However, I don't
think adding the LWT route directly using nl is a good idea here so I'll
make the NS1 use a regular xfrmi.
>
> https://github.com/kernel-patches/bpf/actions/runs/3578467213/jobs/6019370754#step:6:6395
>
> > +             return -1;
> > +     }
> > +     return 0;
> > +}
> > +
> > +void serial_test_xfrm_info(void)
>
> Remove "serial_".  New test must be able to run in parallel ("./test_progs -j").

Ok.

>
> > +{
> > +     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())
> > +      */
>
> I think this comment is mostly inherited from other tests (eg. tc_redirect.c)
> but the pthread dance is actually unnecessary.  The test_progs.c will restore
> the original netns before running the next test.  I am abort to remove this from
> the tc_redirect.c also.  Please also avoid this pthread create here.

Ok. Indeed was inherited.

>
> > +     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
>
>
> Nit. Same here. Just xfrm_info.c.

Ok.

>
> > @@ -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)
>
> Please try not to use unnecessary bpf_printk().  BPF CI is not capturing it also.

Ok.

>
> > +
> > +struct {
> > +     __uint(type, BPF_MAP_TYPE_ARRAY);
> > +     __uint(max_entries, 2);
> > +     __type(key, __u32);
> > +     __type(value, __u32);
> > +} dst_if_id_map SEC(".maps");
>
> It is easier to use global variables instead of a map.

Would these be available for read/write from the test application (as the
map is currently populated/read from userspace)?

>
> > +
> > +struct bpf_xfrm_info {
> > +     __u32 if_id;
> > +     int link;
> > +};
>
> This needs __attribute__((preserve_access_index) for CO-RE.
> It is easier to just include vmlinux.h to get the struct xfrm_md_info { ... }.

Ok.

>
> > +
> > +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";
>

Thanks for the review!
Eyal.
Martin KaFai Lau Dec. 1, 2022, 7:33 a.m. UTC | #4
On 11/30/22 9:34 PM, Eyal Birger wrote:
>>> +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__);
>>
>> Unfortunately, the BPF CI iproute2 does not have this support also :(
>> I am worry it will just stay SKIP for some time and rot.  Can you try to
>> directly use netlink here?
> 
> Yeah, I wasn't sure if adding a libmnl (or alternative) dependency
> was ok here, and also didn't want to copy all that nl logic here.
> So I figured it would get there eventually.
> 
> I noticed libmnl is used by the nf tests, so maybe its inclusion isn't too
> bad. Unless there's a better approach.

I wasn't thinking about including the libmnl.  I am thinking about something 
lightweight like the bpf_tc_hook_create() used in this test. 
bpf_tc_hook_create() is in libbpf's netlink.c.  Not sure if this netlink 
link-add helper belongs to libbpf though, so it will be better just stay here in 
this selftest for now.  If it is too complicated without libmnl, leave it as 
SKIP for now is an option and I will try to run it manually first with a newer 
iproute2.

will reply other comments tomorrow.
Eyal Birger Dec. 1, 2022, 1:33 p.m. UTC | #5
Hi Martin,

On Thu, Dec 1, 2022 at 9:33 AM Martin KaFai Lau <martin.lau@linux.dev> wrote:
>
> On 11/30/22 9:34 PM, Eyal Birger wrote:
> >>> +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__);
> >>
> >> Unfortunately, the BPF CI iproute2 does not have this support also :(
> >> I am worry it will just stay SKIP for some time and rot.  Can you try to
> >> directly use netlink here?
> >
> > Yeah, I wasn't sure if adding a libmnl (or alternative) dependency
> > was ok here, and also didn't want to copy all that nl logic here.
> > So I figured it would get there eventually.
> >
> > I noticed libmnl is used by the nf tests, so maybe its inclusion isn't too
> > bad. Unless there's a better approach.
>
> I wasn't thinking about including the libmnl.  I am thinking about something
> lightweight like the bpf_tc_hook_create() used in this test.
> bpf_tc_hook_create() is in libbpf's netlink.c.  Not sure if this netlink
> link-add helper belongs to libbpf though, so it will be better just stay here in
> this selftest for now.  If it is too complicated without libmnl, leave it as
> SKIP for now is an option and I will try to run it manually first with a newer
> iproute2.

Looks like it doesn't turn out too bad imho without libmnl, basically
needs a few rtattr helpers.
Will do it that way in v3.

Eyal.
Martin KaFai Lau Dec. 1, 2022, 8:26 p.m. UTC | #6
On 11/30/22 9:34 PM, Eyal Birger wrote:
>>> +
>>> +struct {
>>> +     __uint(type, BPF_MAP_TYPE_ARRAY);
>>> +     __uint(max_entries, 2);
>>> +     __type(key, __u32);
>>> +     __type(value, __u32);
>>> +} dst_if_id_map SEC(".maps");
>>
>> It is easier to use global variables instead of a map.
> 
> Would these be available for read/write from the test application (as the
> map is currently populated/read from userspace)?

Yes, through the skel->bss->...
selftests/bpf/prog_tests/ has examples.
Eyal Birger Dec. 1, 2022, 8:48 p.m. UTC | #7
On Thu, Dec 1, 2022 at 10:26 PM Martin KaFai Lau <martin.lau@linux.dev> wrote:
>
> On 11/30/22 9:34 PM, Eyal Birger wrote:
> >>> +
> >>> +struct {
> >>> +     __uint(type, BPF_MAP_TYPE_ARRAY);
> >>> +     __uint(max_entries, 2);
> >>> +     __type(key, __u32);
> >>> +     __type(value, __u32);
> >>> +} dst_if_id_map SEC(".maps");
> >>
> >> It is easier to use global variables instead of a map.
> >
> > Would these be available for read/write from the test application (as the
> > map is currently populated/read from userspace)?
>
> Yes, through the skel->bss->...
> selftests/bpf/prog_tests/ has examples.

Oh this is very useful! I tested and indeed this works perfectly.
WIll use in v3.

Thanks!
Eyal.
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..3aef72540934
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c
@@ -0,0 +1,343 @@ 
+// 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 external");
+	SYS("ip -net " NS1 " addr add 192.168.1.200/32 dev ipsec0");
+	SYS("ip -net " NS1 " link set dev ipsec0 up");
+	SYS("ip -net " NS1 " route add 192.168.1.100/32 dev ipsec0 encap xfrm if_id %d", IF_ID_1);
+
+	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";