[PATCH bpf-next V1 2/2] selftests/bpf: Tests using bpf_check_mtu BPF-helper input mtu_len param
From: Jesper Dangaard Brouer <hidden>
Date: 2021-02-15 16:08:46
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Shuah Khan, Linus Torvalds
Add tests that use mtu_len as input parameter in BPF-helper bpf_check_mtu(). The BPF-helper is avail from both XDP and TC context. Add two tests per context, one that tests below MTU and one that exceeds the MTU. Signed-off-by: Jesper Dangaard Brouer <redacted> --- tools/testing/selftests/bpf/prog_tests/check_mtu.c | 4 + tools/testing/selftests/bpf/progs/test_check_mtu.c | 92 ++++++++++++++++++++ 2 files changed, 96 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/check_mtu.c b/tools/testing/selftests/bpf/prog_tests/check_mtu.c
index 36af1c138faf..b62a39315336 100644
--- a/tools/testing/selftests/bpf/prog_tests/check_mtu.c
+++ b/tools/testing/selftests/bpf/prog_tests/check_mtu.c@@ -128,6 +128,8 @@ static void test_check_mtu_xdp(__u32 mtu, __u32 ifindex) test_check_mtu_run_xdp(skel, skel->progs.xdp_use_helper, mtu); test_check_mtu_run_xdp(skel, skel->progs.xdp_exceed_mtu, mtu); test_check_mtu_run_xdp(skel, skel->progs.xdp_minus_delta, mtu); + test_check_mtu_run_xdp(skel, skel->progs.xdp_input_len, mtu); + test_check_mtu_run_xdp(skel, skel->progs.xdp_input_len_exceed, mtu); cleanup: test_check_mtu__destroy(skel);
@@ -187,6 +189,8 @@ static void test_check_mtu_tc(__u32 mtu, __u32 ifindex) test_check_mtu_run_tc(skel, skel->progs.tc_exceed_mtu, mtu); test_check_mtu_run_tc(skel, skel->progs.tc_exceed_mtu_da, mtu); test_check_mtu_run_tc(skel, skel->progs.tc_minus_delta, mtu); + test_check_mtu_run_tc(skel, skel->progs.tc_input_len, mtu); + test_check_mtu_run_tc(skel, skel->progs.tc_input_len_exceed, mtu); cleanup: test_check_mtu__destroy(skel); }
diff --git a/tools/testing/selftests/bpf/progs/test_check_mtu.c b/tools/testing/selftests/bpf/progs/test_check_mtu.c
index b7787b43f9db..c4a9bae96e75 100644
--- a/tools/testing/selftests/bpf/progs/test_check_mtu.c
+++ b/tools/testing/selftests/bpf/progs/test_check_mtu.c@@ -105,6 +105,54 @@ int xdp_minus_delta(struct xdp_md *ctx) return retval; } +SEC("xdp") +int xdp_input_len(struct xdp_md *ctx) +{ + int retval = XDP_PASS; /* Expected retval on successful test */ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + __u32 ifindex = GLOBAL_USER_IFINDEX; + __u32 data_len = data_end - data; + + /* API allow user give length to check as input via mtu_len param, + * resulting MTU value is still output in mtu_len param after call. + * + * Input len is L3, like MTU and iph->tot_len. + * Remember XDP data_len is L2. + */ + __u32 mtu_len = data_len - ETH_HLEN; + + if (bpf_check_mtu(ctx, ifindex, &mtu_len, 0, 0)) + retval = XDP_ABORTED; + + global_bpf_mtu_xdp = mtu_len; + return retval; +} + +SEC("xdp") +int xdp_input_len_exceed(struct xdp_md *ctx) +{ + int retval = XDP_ABORTED; /* Fail */ + __u32 ifindex = GLOBAL_USER_IFINDEX; + int err; + + /* API allow user give length to check as input via mtu_len param, + * resulting MTU value is still output in mtu_len param after call. + * + * Input length value is L3 size like MTU. + */ + __u32 mtu_len = GLOBAL_USER_MTU; + + mtu_len += 1; /* Exceed with 1 */ + + err = bpf_check_mtu(ctx, ifindex, &mtu_len, 0, 0); + if (err == BPF_MTU_CHK_RET_FRAG_NEEDED) + retval = XDP_PASS ; /* Success in exceeding MTU check */ + + global_bpf_mtu_xdp = mtu_len; + return retval; +} + SEC("classifier") int tc_use_helper(struct __sk_buff *ctx) {
@@ -196,3 +244,47 @@ int tc_minus_delta(struct __sk_buff *ctx) global_bpf_mtu_xdp = mtu_len; return retval; } + +SEC("classifier") +int tc_input_len(struct __sk_buff *ctx) +{ + int retval = BPF_OK; /* Expected retval on successful test */ + __u32 ifindex = GLOBAL_USER_IFINDEX; + + /* API allow user give length to check as input via mtu_len param, + * resulting MTU value is still output in mtu_len param after call. + * + * Input length value is L3 size. + */ + __u32 mtu_len = GLOBAL_USER_MTU; + + if (bpf_check_mtu(ctx, ifindex, &mtu_len, 0, 0)) + retval = BPF_DROP; + + global_bpf_mtu_xdp = mtu_len; + return retval; +} + +SEC("classifier") +int tc_input_len_exceed(struct __sk_buff *ctx) +{ + int retval = BPF_DROP; /* Fail */ + __u32 ifindex = GLOBAL_USER_IFINDEX; + int err; + + /* API allow user give length to check as input via mtu_len param, + * resulting MTU value is still output in mtu_len param after call. + * + * Input length value is L3 size like MTU. + */ + __u32 mtu_len = GLOBAL_USER_MTU; + + mtu_len += 1; /* Exceed with 1 */ + + err = bpf_check_mtu(ctx, ifindex, &mtu_len, 0, 0); + if (err == BPF_MTU_CHK_RET_FRAG_NEEDED) + retval = BPF_OK; /* Success in exceeding MTU check */ + + global_bpf_mtu_xdp = mtu_len; + return retval; +}