[PATCH ipsec-next v3 2/9] bpf: xfrm: Add bpf_xdp_xfrm_state_release() kfunc

Daniel Xu
2023-12-01T20:24:01Z

This kfunc releases a previously acquired xfrm_state from
bpf_xdp_get_xfrm_state().

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>
---
net/xfrm/xfrm_state_bpf.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/net/xfrm/xfrm_state_bpf.c b/net/xfrm/xfrm_state_bpf.c
index 1681825db506..1485b9da9425 100644
--- a/net/xfrm/xfrm_state_bpf.c
+++ b/net/xfrm/xfrm_state_bpf.c
@@ -94,10 +94,26 @@ bpf_xdp_get_xfrm_state(struct xdp_md *ctx, struct bpf_xfrm_state_opts *opts, u32
return x;
}

+/* bpf_xdp_xfrm_state_release - Release acquired xfrm_state object
+ *
+ * This must be invoked for referenced PTR_TO_BTF_ID, and the verifier rejects
+ * the program if any references remain in the program in all of the explored
+ * states.
+ *
+ * Parameters:
+ * @x - Pointer to referenced xfrm_state object, obtained using
+ * bpf_xdp_get_xfrm_state.
+ */
+__bpf_kfunc void bpf_xdp_xfrm_state_release(struct xfrm_state *x)
+{
+ xfrm_state_put(x);
+}
+
__bpf_kfunc_end_defs();

BTF_SET8_START(xfrm_state_kfunc_set)
BTF_ID_FLAGS(func, bpf_xdp_get_xfrm_state, KF_RET_NULL | KF_ACQUIRE)
+BTF_ID_FLAGS(func, bpf_xdp_xfrm_state_release, KF_RELEASE)
BTF_SET8_END(xfrm_state_kfunc_set)

static const struct btf_kfunc_id_set xfrm_state_xdp_kfunc_set = {
--
2.42.1