[PATCH bpf-next v2 4/4] selftests/bpf: Add tests for writing to nf_conn:mark

Add a simple extension to the existing selftest to write to
nf_conn:mark. Also add a failure test for writing to unsupported field.

Signed-off-by: Daniel Xu <redacted>
---
 tools/testing/selftests/bpf/prog_tests/bpf_nf.c    |  1 +
 tools/testing/selftests/bpf/progs/test_bpf_nf.c    |  6 ++++--
 .../testing/selftests/bpf/progs/test_bpf_nf_fail.c | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
index 544bf90ac2a7..45389c39f211 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c

@@ -17,6 +17,7 @@ struct {
        { "set_status_after_insert", "kernel function bpf_ct_set_status args#0 expected pointer to STRUCT nf_conn___init but" },
        { "change_timeout_after_alloc", "kernel function bpf_ct_change_timeout args#0 expected pointer to STRUCT nf_conn but" },
        { "change_status_after_alloc", "kernel function bpf_ct_change_status args#0 expected pointer to STRUCT nf_conn but" },
+       { "write_not_allowlisted_field", "no write support to nf_conn at off" },
 };

 enum {

diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf.c b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
index 2722441850cc..638b6642d20f 100644
--- a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
+++ b/tools/testing/selftests/bpf/progs/test_bpf_nf.c

@@ -175,8 +175,10 @@ nf_ct_test(struct nf_conn *(*lookup_fn)(void *, struct bpf_sock_tuple *, u32,
                       sizeof(opts_def));
        if (ct) {
                test_exist_lookup = 0;
-               if (ct->mark == 42)
-                       test_exist_lookup_mark = 43;
+               if (ct->mark == 42) {
+                       ct->mark++;

+                       test_exist_lookup_mark = ct->mark;
+               }
                bpf_ct_release(ct);
        } else {
                test_exist_lookup = opts_def.error;

diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf_fail.c b/tools/testing/selftests/bpf/progs/test_bpf_nf_fail.c
index bf79af15c808..0e4759ab38ff 100644
--- a/tools/testing/selftests/bpf/progs/test_bpf_nf_fail.c
+++ b/tools/testing/selftests/bpf/progs/test_bpf_nf_fail.c

@@ -69,6 +69,20 @@ int lookup_insert(struct __sk_buff *ctx)
        return 0;
 }

+SEC("?tc")
+int write_not_allowlisted_field(struct __sk_buff *ctx)
+{
+       struct bpf_ct_opts___local opts = {};
+       struct bpf_sock_tuple tup = {};
+       struct nf_conn *ct;
+
+       ct = bpf_skb_ct_lookup(ctx, &tup, sizeof(tup.ipv4), &opts, sizeof(opts));
+       if (!ct)
+               return 0;
+       ct->status = 0xF00;
+       return 0;
+}
+
 SEC("?tc")
 int set_timeout_after_insert(struct __sk_buff *ctx)
 {
--

2.37.1