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-rw-r--r--net/mptcp/sched.c173
1 files changed, 173 insertions, 0 deletions
diff --git a/net/mptcp/sched.c b/net/mptcp/sched.c
new file mode 100644
index 0000000000..4ab0693c06
--- /dev/null
+++ b/net/mptcp/sched.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2022, SUSE.
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/rculist.h>
+#include <linux/spinlock.h>
+#include "protocol.h"
+
+static DEFINE_SPINLOCK(mptcp_sched_list_lock);
+static LIST_HEAD(mptcp_sched_list);
+
+static int mptcp_sched_default_get_subflow(struct mptcp_sock *msk,
+ struct mptcp_sched_data *data)
+{
+ struct sock *ssk;
+
+ ssk = data->reinject ? mptcp_subflow_get_retrans(msk) :
+ mptcp_subflow_get_send(msk);
+ if (!ssk)
+ return -EINVAL;
+
+ mptcp_subflow_set_scheduled(mptcp_subflow_ctx(ssk), true);
+ return 0;
+}
+
+static struct mptcp_sched_ops mptcp_sched_default = {
+ .get_subflow = mptcp_sched_default_get_subflow,
+ .name = "default",
+ .owner = THIS_MODULE,
+};
+
+/* Must be called with rcu read lock held */
+struct mptcp_sched_ops *mptcp_sched_find(const char *name)
+{
+ struct mptcp_sched_ops *sched, *ret = NULL;
+
+ list_for_each_entry_rcu(sched, &mptcp_sched_list, list) {
+ if (!strcmp(sched->name, name)) {
+ ret = sched;
+ break;
+ }
+ }
+
+ return ret;
+}
+
+int mptcp_register_scheduler(struct mptcp_sched_ops *sched)
+{
+ if (!sched->get_subflow)
+ return -EINVAL;
+
+ spin_lock(&mptcp_sched_list_lock);
+ if (mptcp_sched_find(sched->name)) {
+ spin_unlock(&mptcp_sched_list_lock);
+ return -EEXIST;
+ }
+ list_add_tail_rcu(&sched->list, &mptcp_sched_list);
+ spin_unlock(&mptcp_sched_list_lock);
+
+ pr_debug("%s registered", sched->name);
+ return 0;
+}
+
+void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched)
+{
+ if (sched == &mptcp_sched_default)
+ return;
+
+ spin_lock(&mptcp_sched_list_lock);
+ list_del_rcu(&sched->list);
+ spin_unlock(&mptcp_sched_list_lock);
+}
+
+void mptcp_sched_init(void)
+{
+ mptcp_register_scheduler(&mptcp_sched_default);
+}
+
+int mptcp_init_sched(struct mptcp_sock *msk,
+ struct mptcp_sched_ops *sched)
+{
+ if (!sched)
+ sched = &mptcp_sched_default;
+
+ if (!bpf_try_module_get(sched, sched->owner))
+ return -EBUSY;
+
+ msk->sched = sched;
+ if (msk->sched->init)
+ msk->sched->init(msk);
+
+ pr_debug("sched=%s", msk->sched->name);
+
+ return 0;
+}
+
+void mptcp_release_sched(struct mptcp_sock *msk)
+{
+ struct mptcp_sched_ops *sched = msk->sched;
+
+ if (!sched)
+ return;
+
+ msk->sched = NULL;
+ if (sched->release)
+ sched->release(msk);
+
+ bpf_module_put(sched, sched->owner);
+}
+
+void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
+ bool scheduled)
+{
+ WRITE_ONCE(subflow->scheduled, scheduled);
+}
+
+int mptcp_sched_get_send(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sched_data data;
+
+ msk_owned_by_me(msk);
+
+ /* the following check is moved out of mptcp_subflow_get_send */
+ if (__mptcp_check_fallback(msk)) {
+ if (msk->first &&
+ __tcp_can_send(msk->first) &&
+ sk_stream_memory_free(msk->first)) {
+ mptcp_subflow_set_scheduled(mptcp_subflow_ctx(msk->first), true);
+ return 0;
+ }
+ return -EINVAL;
+ }
+
+ mptcp_for_each_subflow(msk, subflow) {
+ if (READ_ONCE(subflow->scheduled))
+ return 0;
+ }
+
+ data.reinject = false;
+ if (msk->sched == &mptcp_sched_default || !msk->sched)
+ return mptcp_sched_default_get_subflow(msk, &data);
+ return msk->sched->get_subflow(msk, &data);
+}
+
+int mptcp_sched_get_retrans(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sched_data data;
+
+ msk_owned_by_me(msk);
+
+ /* the following check is moved out of mptcp_subflow_get_retrans */
+ if (__mptcp_check_fallback(msk))
+ return -EINVAL;
+
+ mptcp_for_each_subflow(msk, subflow) {
+ if (READ_ONCE(subflow->scheduled))
+ return 0;
+ }
+
+ data.reinject = true;
+ if (msk->sched == &mptcp_sched_default || !msk->sched)
+ return mptcp_sched_default_get_subflow(msk, &data);
+ return msk->sched->get_subflow(msk, &data);
+}