[mptcp-next,v2,1/3] mptcp: define struct mptcp_pm_ops

Commit Message

Geliang Tang Jan. 15, 2025, 10:09 a.m. UTC

From: Geliang Tang <[e-mail]>

In order to allow users to develop their own BPF-based path manager,
this patch defines a struct ops "mptcp_pm_ops" for a userspace path
manager, which contains a set of interfaces.

Add a set of functions to register, unregister, find and validate a
given struct ops.

Signed-off-by: Geliang Tang <[e-mail]>
---
 include/net/mptcp.h      | 27 +++++++++++++++++++
 net/mptcp/pm_userspace.c | 57 ++++++++++++++++++++++++++++++++++++++++
 net/mptcp/protocol.h     |  5 ++++
 3 files changed, 89 insertions(+)

Patch

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 94d5976f7b8d..0918b91a29ab 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -14,6 +14,7 @@ 
 
 struct mptcp_info;
 struct mptcp_sock;
+struct mptcp_pm_addr_entry;
 struct seq_file;
 
 /* MPTCP sk_buff extension data */
@@ -120,6 +121,32 @@  struct mptcp_sched_ops {
 	void (*release)(struct mptcp_sock *msk);
 } ____cacheline_aligned_in_smp;
 
+struct mptcp_pm_ops {
+	int (*address_announce)(struct mptcp_sock *msk,
+				struct mptcp_pm_addr_entry *local);
+	int (*address_remove)(struct mptcp_sock *msk, u8 id);
+	int (*subflow_create)(struct mptcp_sock *msk,
+			      struct mptcp_pm_addr_entry *local,
+			      struct mptcp_addr_info *remote);
+	int (*subflow_destroy)(struct mptcp_sock *msk,
+			       struct mptcp_pm_addr_entry *local,
+			       struct mptcp_addr_info *remote);
+	int (*get_local_id)(struct mptcp_sock *msk,
+			    struct mptcp_pm_addr_entry *local);
+	u8 (*get_flags)(struct mptcp_sock *msk,
+			struct mptcp_addr_info *skc);
+	int (*set_flags)(struct mptcp_sock *msk,
+			 struct mptcp_pm_addr_entry *local,
+			 struct mptcp_addr_info *remote);
+
+	u8			type;
+	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/pm_userspace.c b/net/mptcp/pm_userspace.c
index 1713e9bb6945..2fdee6f22113 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -4,6 +4,8 @@ 
  * Copyright (c) 2022, Intel Corporation.
  */
 
+#include <linux/rculist.h>
+#include <linux/spinlock.h>
 #include "protocol.h"
 #include "mib.h"
 #include "mptcp_pm_gen.h"
@@ -12,6 +14,9 @@ 
 	list_for_each_entry(__entry,						\
 			    &((__msk)->pm.userspace_pm_local_addr_list), list)
 
+static DEFINE_SPINLOCK(mptcp_pm_list_lock);
+static LIST_HEAD(mptcp_pm_list);
+
 void mptcp_free_local_addr_list(struct mptcp_sock *msk)
 {
 	struct mptcp_pm_addr_entry *entry, *tmp;
@@ -681,3 +686,55 @@  int mptcp_userspace_pm_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,
 	sock_put(sk);
 	return ret;
 }
+
+/* Must be called with rcu read lock held */
+struct mptcp_pm_ops *mptcp_pm_find(enum mptcp_pm_type type)
+{
+	struct mptcp_pm_ops *pm;
+
+	list_for_each_entry_rcu(pm, &mptcp_pm_list, list) {
+		if (pm->type == type)
+			return pm;
+	}
+
+	return NULL;
+}
+
+int mptcp_validate_path_manager(struct mptcp_pm_ops *pm)
+{
+	if (!pm->address_announce && !pm->address_remove &&
+	    !pm->subflow_create && !pm->subflow_destroy &&
+	    !pm->get_local_id && !pm->get_flags && !pm->set_flags) {
+		pr_err("%u does not implement required ops\n", pm->type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int mptcp_register_path_manager(struct mptcp_pm_ops *pm)
+{
+	int ret;
+
+	ret = mptcp_validate_path_manager(pm);
+	if (ret)
+		return ret;
+
+	spin_lock(&mptcp_pm_list_lock);
+	if (mptcp_pm_find(pm->type)) {
+		spin_unlock(&mptcp_pm_list_lock);
+		return -EEXIST;
+	}
+	list_add_tail_rcu(&pm->list, &mptcp_pm_list);
+	spin_unlock(&mptcp_pm_list_lock);
+
+	pr_debug("userspace_pm type %u registered\n", pm->type);
+	return 0;
+}
+
+void mptcp_unregister_path_manager(struct mptcp_pm_ops *pm)
+{
+	spin_lock(&mptcp_pm_list_lock);
+	list_del_rcu(&pm->list);
+	spin_unlock(&mptcp_pm_list_lock);
+}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index e8d8236a40e1..64254c57be01 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1048,6 +1048,11 @@  int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_
 void mptcp_pm_remove_addr_entry(struct mptcp_sock *msk,
 				struct mptcp_pm_addr_entry *entry);
 
+struct mptcp_pm_ops *mptcp_pm_find(enum mptcp_pm_type type);
+int mptcp_validate_path_manager(struct mptcp_pm_ops *pm);
+int mptcp_register_path_manager(struct mptcp_pm_ops *pm);
+void mptcp_unregister_path_manager(struct mptcp_pm_ops *pm);
+
 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
 
 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,