[PATCH bpf-next 2/3] selftests/bpf: add tests for TCP_BPF_SOCK_OPS_CB_FLAGS

Alan Maguire
2024-08-02T15:30:05Z

Add tests to set/get TCP sockopt TCP_BPF_SOCK_OPS_CB_FLAGS via
bpf_setsockopt() and also add a cgroup/setsockopt program that
catches setsockopt() for this option and uses bpf_setsockopt()
to set it. The latter allows us to support modifying sockops
cb flags on a per-socket basis via setsockopt() without adding
support into core setsockopt() itself.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
---
.../selftests/bpf/prog_tests/setget_sockopt.c | 11 ++++++
.../selftests/bpf/progs/setget_sockopt.c | 37 +++++++++++++++++--
2 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/setget_sockopt.c b/tools/testing/selftests/bpf/prog_tests/setget_sockopt.c
index 7d4a9b3d3722..b9c54217a489 100644
--- a/tools/testing/selftests/bpf/prog_tests/setget_sockopt.c
+++ b/tools/testing/selftests/bpf/prog_tests/setget_sockopt.c
@@ -42,6 +42,7 @@ static int create_netns(void)
static void test_tcp(int family)
{
struct setget_sockopt__bss *bss = skel->bss;
+ int cb_flags = BPF_SOCK_OPS_STATE_CB_FLAG | BPF_SOCK_OPS_RTO_CB_FLAG;
int sfd, cfd;

memset(bss, 0, sizeof(*bss));
@@ -56,6 +57,9 @@ static void test_tcp(int family)
close(sfd);
return;
}
+ ASSERT_EQ(setsockopt(sfd, SOL_TCP, TCP_BPF_SOCK_OPS_CB_FLAGS,
+ &cb_flags, sizeof(cb_flags)),
+ 0, "setsockopt cb_flags");
close(sfd);
close(cfd);

@@ -65,6 +69,8 @@ static void test_tcp(int family)
ASSERT_EQ(bss->nr_passive, 1, "nr_passive");
ASSERT_EQ(bss->nr_socket_post_create, 2, "nr_socket_post_create");
ASSERT_EQ(bss->nr_binddev, 2, "nr_bind");
+ ASSERT_GE(bss->nr_state, 1, "nr_state");
+ ASSERT_EQ(bss->nr_setsockopt, 1, "nr_setsockopt");
}

static void test_udp(int family)
@@ -185,6 +191,11 @@ void test_setget_sockopt(void)
if (!ASSERT_OK_PTR(skel->links.socket_post_create, "attach_cgroup"))
goto done;

+ skel->links.tcp_setsockopt =
+ bpf_program__attach_cgroup(skel->progs.tcp_setsockopt, cg_fd);
+ if (!ASSERT_OK_PTR(skel->links.tcp_setsockopt, "attach_setsockopt"))
+ goto done;
+
test_tcp(AF_INET6);
test_tcp(AF_INET);
test_udp(AF_INET6);
diff --git a/tools/testing/selftests/bpf/progs/setget_sockopt.c b/tools/testing/selftests/bpf/progs/setget_sockopt.c
index 60518aed1ffc..920af9e21e84 100644
--- a/tools/testing/selftests/bpf/progs/setget_sockopt.c
+++ b/tools/testing/selftests/bpf/progs/setget_sockopt.c
@@ -20,6 +20,8 @@ int nr_connect;
int nr_binddev;
int nr_socket_post_create;
int nr_fin_wait1;
+int nr_state;
+int nr_setsockopt;

struct sockopt_test {
int opt;
@@ -59,6 +61,8 @@ static const struct sockopt_test sol_tcp_tests[] = {
{ .opt = TCP_THIN_LINEAR_TIMEOUTS, .flip = 1, },
{ .opt = TCP_USER_TIMEOUT, .new = 123400, .expected = 123400, },
{ .opt = TCP_NOTSENT_LOWAT, .new = 1314, .expected = 1314, },
+ { .opt = TCP_BPF_SOCK_OPS_CB_FLAGS, .new = BPF_SOCK_OPS_ALL_CB_FLAGS,
+ .expected = BPF_SOCK_OPS_ALL_CB_FLAGS, .restore = BPF_SOCK_OPS_STATE_CB_FLAG, },
{ .opt = 0, },
};

@@ -124,6 +128,7 @@ static int bpf_test_sockopt_int(void *ctx, struct sock *sk,

if (bpf_setsockopt(ctx, level, opt, &new, sizeof(new)))
return 1;
+
if (bpf_getsockopt(ctx, level, opt, &tmp, sizeof(tmp)) ||
tmp != expected)
return 1;
@@ -384,11 +389,14 @@ int skops_sockopt(struct bpf_sock_ops *skops)
nr_passive += !(bpf_test_sockopt(skops, sk) ||
test_tcp_maxseg(skops, sk) ||
test_tcp_saved_syn(skops, sk));
- bpf_sock_ops_cb_flags_set(skops,
- skops->bpf_sock_ops_cb_flags |
- BPF_SOCK_OPS_STATE_CB_FLAG);
+
+ /* no need to set sockops cb flags here as sockopt
+ * tests and user-space originated setsockopt() will
+ * set flags to include BPF_SOCK_OPS_STATE_CB.
+ */
break;
case BPF_SOCK_OPS_STATE_CB:
+ nr_state++;
if (skops->args[1] == BPF_TCP_CLOSE_WAIT)
nr_fin_wait1 += !bpf_test_sockopt(skops, sk);
break;
@@ -397,4 +405,27 @@ int skops_sockopt(struct bpf_sock_ops *skops)
return 1;
}

+SEC("cgroup/setsockopt")
+int tcp_setsockopt(struct bpf_sockopt *ctx)
+{
+ struct bpf_sock *sk = ctx->sk;
+ __u8 *optval_end = ctx->optval_end;
+ __u8 *optval = ctx->optval;
+ int val = 0;
+
+ if (!sk || ctx->level != SOL_TCP || ctx->optname != TCP_BPF_SOCK_OPS_CB_FLAGS)
+ return 1;
+ if (optval + sizeof(int) > optval_end)
+ return 0;
+ if (ctx->optlen != sizeof(int))
+ return 0;
+ val = *(int *)optval;
+ if (bpf_setsockopt(sk, ctx->level, ctx->optname, &val, sizeof(val)))
+ return 0;
+ nr_setsockopt++;
+ /* BPF has handled this no need to call "real" setsockopt() */
+ ctx->optlen = -1;
+ return 1;
+}
+
char _license[] SEC("license") = "GPL";
--
2.31.1