[PATCH bpf-next/net 1/5] bpf: Register mptcp common kfunc set

["Matthieu Baerts (NGI0)" <matttbe@xxxxxxxxxx>]

From: Geliang Tang <tanggeliang@xxxxxxxxxx>

MPTCP helper mptcp_sk() is used to convert struct sock to mptcp_sock.
Helpers mptcp_subflow_ctx() and mptcp_subflow_tcp_sock() are used to
convert between struct mptcp_subflow_context and sock. They all will
be used in MPTCP BPF programs too.

This patch defines corresponding wrappers of them, and put the
wrappers into mptcp common kfunc set and register the set with the
flag BPF_PROG_TYPE_UNSPEC to let them accessible to all types of BPF
programs.

Signed-off-by: Geliang Tang <tanggeliang@xxxxxxxxxx>
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
 net/mptcp/bpf.c | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
index 8a16672b94e2384f5263e1432296cbca1236bb30..6f96a5927fd371f8ea92cbf96c875edef9272b98 100644
--- a/net/mptcp/bpf.c
+++ b/net/mptcp/bpf.c
@@ -29,8 +29,46 @@ static const struct btf_kfunc_id_set bpf_mptcp_fmodret_set = {
 	.set   = &bpf_mptcp_fmodret_ids,
 };
 
+__bpf_kfunc_start_defs();
+
+__bpf_kfunc static struct mptcp_sock *bpf_mptcp_sk(struct sock *sk)
+{
+	return mptcp_sk(sk);
+}
+
+__bpf_kfunc static struct mptcp_subflow_context *
+bpf_mptcp_subflow_ctx(const struct sock *sk)
+{
+	return mptcp_subflow_ctx(sk);
+}
+
+__bpf_kfunc static struct sock *
+bpf_mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
+{
+	return mptcp_subflow_tcp_sock(subflow);
+}
+
+__bpf_kfunc_end_defs();
+
+BTF_KFUNCS_START(bpf_mptcp_common_kfunc_ids)
+BTF_ID_FLAGS(func, bpf_mptcp_sk)
+BTF_ID_FLAGS(func, bpf_mptcp_subflow_ctx)
+BTF_ID_FLAGS(func, bpf_mptcp_subflow_tcp_sock)
+BTF_KFUNCS_END(bpf_mptcp_common_kfunc_ids)
+
+static const struct btf_kfunc_id_set bpf_mptcp_common_kfunc_set = {
+	.owner	= THIS_MODULE,
+	.set	= &bpf_mptcp_common_kfunc_ids,
+};
+
 static int __init bpf_mptcp_kfunc_init(void)
 {
-	return register_btf_fmodret_id_set(&bpf_mptcp_fmodret_set);
+	int ret;
+
+	ret = register_btf_fmodret_id_set(&bpf_mptcp_fmodret_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC,
+					       &bpf_mptcp_common_kfunc_set);
+
+	return ret;
 }
 late_initcall(bpf_mptcp_kfunc_init);

-- 
2.45.2