[PATCH bpf-next v6 5/5] bpf: xfrm: Add selftest for bpf_xdp_get_xfrm_state()

Daniel Xu
2023-12-14T22:49:43Z

This commit extends test_tunnel selftest to test the new XDP xfrm state
lookup kfunc.

Co-developed-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
---
.../selftests/bpf/prog_tests/test_tunnel.c | 16 +++++-
.../selftests/bpf/progs/test_tunnel_kern.c | 51 +++++++++++++++++++
2 files changed, 65 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/test_tunnel.c b/tools/testing/selftests/bpf/prog_tests/test_tunnel.c
index 2d7f8fa82ebd..2b3c6dd66259 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_tunnel.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_tunnel.c
@@ -278,7 +278,7 @@ static int add_xfrm_tunnel(void)
SYS(fail,
"ip netns exec at_ns0 "
"ip xfrm state add src %s dst %s proto esp "
- "spi %d reqid 1 mode tunnel "
+ "spi %d reqid 1 mode tunnel replay-window 42 "
"auth-trunc 'hmac(sha1)' %s 96 enc 'cbc(aes)' %s",
IP4_ADDR_VETH0, IP4_ADDR1_VETH1, XFRM_SPI_IN_TO_OUT, XFRM_AUTH, XFRM_ENC);
SYS(fail,
@@ -313,7 +313,7 @@ static int add_xfrm_tunnel(void)
*/
SYS(fail,
"ip xfrm state add src %s dst %s proto esp "
- "spi %d reqid 1 mode tunnel "
+ "spi %d reqid 1 mode tunnel replay-window 42 "
"auth-trunc 'hmac(sha1)' %s 96 enc 'cbc(aes)' %s",
IP4_ADDR_VETH0, IP4_ADDR1_VETH1, XFRM_SPI_IN_TO_OUT, XFRM_AUTH, XFRM_ENC);
SYS(fail,
@@ -628,8 +628,10 @@ static void test_xfrm_tunnel(void)
{
DECLARE_LIBBPF_OPTS(bpf_tc_hook, tc_hook,
.attach_point = BPF_TC_INGRESS);
+ LIBBPF_OPTS(bpf_xdp_attach_opts, opts);
struct test_tunnel_kern *skel = NULL;
struct nstoken *nstoken;
+ int xdp_prog_fd;
int tc_prog_fd;
int ifindex;
int err;
@@ -654,6 +656,14 @@ static void test_xfrm_tunnel(void)
if (attach_tc_prog(&tc_hook, tc_prog_fd, -1))
goto done;

+ /* attach xdp prog to tunnel dev */
+ xdp_prog_fd = bpf_program__fd(skel->progs.xfrm_get_state_xdp);
+ if (!ASSERT_GE(xdp_prog_fd, 0, "bpf_program__fd"))
+ goto done;
+ err = bpf_xdp_attach(ifindex, xdp_prog_fd, XDP_FLAGS_REPLACE, &opts);
+ if (!ASSERT_OK(err, "bpf_xdp_attach"))
+ goto done;
+
/* ping from at_ns0 namespace test */
nstoken = open_netns("at_ns0");
err = test_ping(AF_INET, IP4_ADDR_TUNL_DEV1);
@@ -667,6 +677,8 @@ static void test_xfrm_tunnel(void)
goto done;
if (!ASSERT_EQ(skel->bss->xfrm_remote_ip, 0xac100164, "remote_ip"))
goto done;
+ if (!ASSERT_EQ(skel->bss->xfrm_replay_window, 42, "replay_window"))
+ goto done;

done:
delete_xfrm_tunnel();
diff --git a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
index 3a59eb9c34de..3e436e6f7312 100644
--- a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
+++ b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
@@ -30,6 +30,10 @@ int bpf_skb_set_fou_encap(struct __sk_buff *skb_ctx,
struct bpf_fou_encap *encap, int type) __ksym;
int bpf_skb_get_fou_encap(struct __sk_buff *skb_ctx,
struct bpf_fou_encap *encap) __ksym;
+struct xfrm_state *
+bpf_xdp_get_xfrm_state(struct xdp_md *ctx, struct bpf_xfrm_state_opts *opts,
+ u32 opts__sz) __ksym;
+void bpf_xdp_xfrm_state_release(struct xfrm_state *x) __ksym;

struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
@@ -950,4 +954,51 @@ int xfrm_get_state(struct __sk_buff *skb)
return TC_ACT_OK;
}

+volatile int xfrm_replay_window = 0;
+
+SEC("xdp")
+int xfrm_get_state_xdp(struct xdp_md *xdp)
+{
+ struct bpf_xfrm_state_opts opts = {};
+ struct xfrm_state *x = NULL;
+ struct ip_esp_hdr *esph;
+ struct bpf_dynptr ptr;
+ u8 esph_buf[8] = {};
+ u8 iph_buf[20] = {};
+ struct iphdr *iph;
+ u32 off;
+
+ if (bpf_dynptr_from_xdp(xdp, 0, &ptr))
+ goto out;
+
+ off = sizeof(struct ethhdr);
+ iph = bpf_dynptr_slice(&ptr, off, iph_buf, sizeof(iph_buf));
+ if (!iph || iph->protocol != IPPROTO_ESP)
+ goto out;
+
+ off += sizeof(struct iphdr);
+ esph = bpf_dynptr_slice(&ptr, off, esph_buf, sizeof(esph_buf));
+ if (!esph)
+ goto out;
+
+ opts.netns_id = BPF_F_CURRENT_NETNS;
+ opts.daddr.a4 = iph->daddr;
+ opts.spi = esph->spi;
+ opts.proto = IPPROTO_ESP;
+ opts.family = AF_INET;
+
+ x = bpf_xdp_get_xfrm_state(xdp, &opts, sizeof(opts));
+ if (!x)
+ goto out;
+
+ if (!x->replay_esn)
+ goto out;
+
+ xfrm_replay_window = x->replay_esn->replay_window;
+out:
+ if (x)
+ bpf_xdp_xfrm_state_release(x);
+ return XDP_PASS;
+}
+
char _license[] SEC("license") = "GPL";
--
2.42.1