mptcp: add struct mptcp_sched_ops

This patch defines struct mptcp_sched_ops, which has three struct members,
name, owner and list, and four function pointers: init(), release() and
get_subflow().

The scheduler function get_subflow() have a struct mptcp_sched_data
parameter, which contains a reinject flag for retrans or not, a subflows
number and a mptcp_subflow_context array.

Add the scheduler registering, unregistering and finding functions to add,
delete and find a packet scheduler on the global list mptcp_sched_list.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-3-0c860fb256a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 3c5c686..fb99612 100644 (file)
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -96,6 +96,27 @@ struct mptcp_out_options {
 #endif
 };
 
+#define MPTCP_SCHED_NAME_MAX   16
+#define MPTCP_SUBFLOWS_MAX     8
+
+struct mptcp_sched_data {
+       bool    reinject;
+       u8      subflows;
+       struct mptcp_subflow_context *contexts[MPTCP_SUBFLOWS_MAX];
+};
+
+struct mptcp_sched_ops {
+       int (*get_subflow)(struct mptcp_sock *msk,
+                          struct mptcp_sched_data *data);
+
+       char                    name[MPTCP_SCHED_NAME_MAX];
+       struct module           *owner;
+       struct list_head        list;
+
+       void (*init)(struct mptcp_sock *msk);
+       void (*release)(struct mptcp_sock *msk);
+} ____cacheline_aligned_in_smp;
+
 #ifdef CONFIG_MPTCP
 void mptcp_init(void);
 

diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
index a3829ce..84e531f 100644 (file)
--- a/net/mptcp/Makefile
+++ b/net/mptcp/Makefile
@@ -2,7 +2,7 @@
 obj-$(CONFIG_MPTCP) += mptcp.o
 
 mptcp-y := protocol.o subflow.o options.o token.o crypto.o ctrl.o pm.o diag.o \
-          mib.o pm_netlink.o sockopt.o pm_userspace.o fastopen.o
+          mib.o pm_netlink.o sockopt.o pm_userspace.o fastopen.o sched.o
 
 obj-$(CONFIG_SYN_COOKIES) += syncookies.o
 obj-$(CONFIG_INET_MPTCP_DIAG) += mptcp_diag.o

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index cbf9a9e..985e8f8 100644 (file)
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -655,6 +655,9 @@ int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
                         struct sockaddr_storage *addr,
                         unsigned short family);
+struct mptcp_sched_ops *mptcp_sched_find(const char *name);
+int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
+void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
 
 static inline bool __tcp_can_send(const struct sock *ssk)
 {

diff --git a/net/mptcp/sched.c b/net/mptcp/sched.c
new file mode 100644 (file)
index 0000000..c5d3bba
--- /dev/null
+++ b/net/mptcp/sched.c
@@ -0,0 +1,56 @@
+// 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);
+
+/* 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)
+{
+       spin_lock(&mptcp_sched_list_lock);
+       list_del_rcu(&sched->list);
+       spin_unlock(&mptcp_sched_list_lock);
+}