bpf: Export mptcp packet scheduler helpers

This patch adds a new struct btf_kfunc_id_set for MPTCP scheduler. Add
mptcp_subflow_set_scheduled() and mptcp_sched_data_set_contexts() helpers
into this id_set, and register it in bpf_mptcp_kfunc_init() to make sure
these helpers can be accessed from the BPF context.

Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Geliang Tang <[email protected]>

Author: Geliang Tang

net/mptcp/bpf.c

@@ -298,6 +298,11 @@ bpf_mptcp_subflow_ctx_by_pos(const struct mptcp_sched_data *data, unsigned int p
 	return data->contexts[pos];
 }
 
+__bpf_kfunc static bool bpf_mptcp_subflow_queues_empty(struct sock *sk)
+{
+	return tcp_rtx_queue_empty(sk);
+}
+
 __bpf_kfunc_end_defs();
 
 BTF_KFUNCS_START(bpf_mptcp_common_kfunc_ids)
@@ -314,13 +319,31 @@ static const struct btf_kfunc_id_set bpf_mptcp_common_kfunc_set = {
 	.set	= &bpf_mptcp_common_kfunc_ids,
 };
 
+BTF_KFUNCS_START(bpf_mptcp_sched_kfunc_ids)
+BTF_ID_FLAGS(func, mptcp_subflow_set_scheduled)
+BTF_ID_FLAGS(func, bpf_mptcp_subflow_ctx_by_pos)
+BTF_ID_FLAGS(func, mptcp_subflow_active)
+BTF_ID_FLAGS(func, mptcp_set_timeout)
+BTF_ID_FLAGS(func, mptcp_wnd_end)
+BTF_ID_FLAGS(func, tcp_stream_memory_free)
+BTF_ID_FLAGS(func, bpf_mptcp_subflow_queues_empty)
+BTF_ID_FLAGS(func, mptcp_pm_subflow_chk_stale)
+BTF_KFUNCS_END(bpf_mptcp_sched_kfunc_ids)
+
+static const struct btf_kfunc_id_set bpf_mptcp_sched_kfunc_set = {
+	.owner	= THIS_MODULE,
+	.set	= &bpf_mptcp_sched_kfunc_ids,
+};
+
 static int __init bpf_mptcp_kfunc_init(void)
 {
 	int ret;
 
 	ret = register_btf_fmodret_id_set(&bpf_mptcp_fmodret_set);
 	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCKOPT,
 					       &bpf_mptcp_common_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS,
+					       &bpf_mptcp_sched_kfunc_set);
 #ifdef CONFIG_BPF_JIT
 	ret = ret ?: register_bpf_struct_ops(&bpf_mptcp_sched_ops, mptcp_sched_ops);
 #endif

net/mptcp/protocol.c

@@ -50,7 +50,7 @@ DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
 static struct net_device mptcp_napi_dev;
 
 /* Returns end sequence number of the receiver's advertised window */
-static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
+u64 mptcp_wnd_end(const struct mptcp_sock *msk)
 {
 	return READ_ONCE(msk->wnd_end);
 }
@@ -423,7 +423,7 @@ static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subfl
 	       inet_csk(ssk)->icsk_timeout - jiffies : 0;
 }
 
-static void mptcp_set_timeout(struct sock *sk)
+void mptcp_set_timeout(struct sock *sk)
 {
 	struct mptcp_subflow_context *subflow;
 	long tout = 0;

net/mptcp/protocol.h

@@ -713,6 +713,8 @@ void __mptcp_subflow_send_ack(struct sock *ssk);
 void mptcp_subflow_reset(struct sock *ssk);
 void mptcp_subflow_queue_clean(struct sock *sk, struct sock *ssk);
 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
+u64 mptcp_wnd_end(const struct mptcp_sock *msk);
+void mptcp_set_timeout(struct sock *sk);
 struct mptcp_subflow_context *
 bpf_mptcp_subflow_ctx_by_pos(const struct mptcp_sched_data *data, unsigned int pos);
 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk);