[PATCH mptcp-next v18 0/7] BPF packet scheduler

[PATCH mptcp-next v18 0/7] BPF packet scheduler

[Geliang Tang]

v18:
 - drop "mptcp: add last_snd write access".
 - add mptcp_sched_data_init helper.
 - move mptcp_sched_get_send() and mptcp_sched_get_retrans() into sched.c.

v17:
 - drop "mptcp: register default scheduler"
 - add back "mptcp: add last_snd write access"
 - update "mptcp: add get_subflow wrappers" as Paolo suggested.
 - fix the issue reported-by kernel test robot <lkp@intel.com> in [1].

[1]
https://patchwork.kernel.org/project/mptcp/patch/8ac278434203662add804d00e007c2cb2b6f52e4.1651024344.git.geliang.tang@suse.com/

v16:
 - add CONFIG_BPF_JIT check around the scheduler code inside bpf.c
 - depends on export/20220426T102605 +
	      Squash to "bpf: add bpf_skc_to_mptcp_sock_proto" +
              Squash to "selftests: bpf: test bpf_skc_to_mptcp_sock"
              Squash to "selftests: bpf: add MPTCP test base"

v15:
 - set mptcp_sched_id and mptcp_sched_type in bpf_mptcp_sched_init().
 - add CONFIG_BPF_JIT in patch 6.
 - drop '#include <sys/param.h>' in patch 8.
 - depends on export/20220426T102605 +
	      Squash to "bpf: add bpf_skc_to_mptcp_sock_proto" +
              Squash to "selftests: bpf: test bpf_skc_to_mptcp_sock"

v14:
 - add struct mptcp_sched_data.

base-commit: export/20220422T060337

v13:
 - rename retrans to reinject
 - drop "add last_snd write access" patch
 - change %lu to %zu to fix the build break on i386.

base-commit: export/20220420T152103

v12:
 - add call_me_again flag.

base-commit: export/20220419T055400

v11:
 - add retrans argment for get_subflow()

base-commit: export/20220408T100826

v10:
 - patch 5: keep msk->last_snd setting in get_subflow().
 - patch 6: add bpf_mptcp_sched_btf_struct_access().
 - patch 8: use MIN() in sys/param.h, instead of defining a new one.
 - update commit logs.

base-commit: export/20220406T054706

v9:
 - patch 2: add the missing mptcp_sched_init() invoking in
   mptcp_proto_init().
 - patch 5: set last_snd after invoking get_subflow().
 - patch 7: merge the squash-to patch.

v8:
 - use global sched_list instead of pernet sched_list.
 - drop synchronize_rcu() in mptcp_unregister_scheduler().
 - update mptcp_init_sched and mptcp_release_sched as Mat and Florian
   suggested.
 - fix the build break in patch 8.
 - depends on: "add skc_to_mptcp_sock" v14.
 - export/20220325T055307

v7:
 - add bpf_try_module_get in mptcp_init_sched.
 - add bpf_module_put in mptcp_release_sched.
 - rename bpf_first to mptcp_bpf_first.
 - update commit logs.

v6:
 - still use pernet sched_list, use current->nsproxy->net_ns in BPF
   context instead of using init_net.
 - patch 1:
   - use rcu_read_lock instead of spin_lock in mptcp_sched_find as Florian suggested.
   - drop synchronize_rcu in sched_exit_net as Florian suggested.
   - keep synchronize_rcu in mptcp_unregister_scheduler, otherwise, got
     a workqueue lockup in my test.
   - update Makefile as Mat suggested.
 - patch 2:
   - add mptcp_sched_data_init to register default sched, instead of
     registering it in init_net.
 - patch 5:
   - move mptcp_sched_get_subflow to protocol.h as Mat suggested.
 - patch 6:
   - use current->nsproxy->net_ns instead of init_net.
 - patch 8:
   - add send_data to send more data, instead of send_byte.

v5:
 - patch 1: define per-namespace sched_list (but only used init_net
   namespace. It is difficult to get 'net' in bpf_mptcp_sched_reg and
   bpf_mptcp_sched_unreg. I need some suggestions here.)
 - patch 2: skip mptcp_sched_default in mptcp_unregister_scheduler.
 - patch 8: add tests into mptcp.c, instead of bpf_tcp_ca.c.

v4:
 - set msk->sched to &mptcp_sched_default when the sched argument is NULL
in mptcp_init_sched().

v3:
 - add mptcp_release_sched helper in patch 4.
 - rename mptcp_set_sched to mptcp_init_sched in patch 4.
 - add mptcp_sched_first_release in patch 7.
 - do some cleanups.

v2:
 - split into more small patches.
 - change all parameters of mptcp_sched_ops from sk to msk:
       void (*init)(struct mptcp_sock *msk);
       void (*release)(struct mptcp_sock *msk);
       struct sock *   (*get_subflow)(struct mptcp_sock *msk);
 - add tests in bpf_tcp_ca.c, instead of adding a new one.

v1:
 - Addressed to the commends in the RFC version.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/75

Geliang Tang (7):
  mptcp: add struct mptcp_sched_ops
  mptcp: add a new sysctl scheduler
  mptcp: add sched in mptcp_sock
  mptcp: add get_subflow wrappers
  mptcp: add bpf_mptcp_sched_ops
  selftests: bpf: add bpf_first scheduler
  selftests: bpf: add bpf_first test

 Documentation/networking/mptcp-sysctl.rst     |   8 +
 include/net/mptcp.h                           |  19 +++
 kernel/bpf/bpf_struct_ops_types.h             |   4 +
 net/mptcp/Makefile                            |   2 +-
 net/mptcp/bpf.c                               | 154 ++++++++++++++++++
 net/mptcp/ctrl.c                              |  14 ++
 net/mptcp/protocol.c                          |  32 ++--
 net/mptcp/protocol.h                          |  10 ++
 net/mptcp/sched.c                             | 143 ++++++++++++++++
 .../testing/selftests/bpf/bpf_mptcp_helpers.h |  19 +++
 .../testing/selftests/bpf/prog_tests/mptcp.c  | 112 +++++++++++++
 .../selftests/bpf/progs/mptcp_bpf_first.c     |  32 ++++
 12 files changed, 529 insertions(+), 20 deletions(-)
 create mode 100644 net/mptcp/sched.c
 create mode 100644 tools/testing/selftests/bpf/progs/mptcp_bpf_first.c

-- 
2.34.1

[PATCH mptcp-next v18 1/7] mptcp: add struct mptcp_sched_ops

[Geliang Tang]

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

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

For supporting a "redundant" packet scheduler in the future, this patch
adds a flag in struct mptcp_sched_data named call_again to indicate that
get_subflow() function needs to be called again.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 include/net/mptcp.h                           | 19 +++++++
 net/mptcp/Makefile                            |  2 +-
 net/mptcp/protocol.h                          |  3 +
 net/mptcp/sched.c                             | 56 +++++++++++++++++++
 .../testing/selftests/bpf/bpf_mptcp_helpers.h | 18 ++++++
 5 files changed, 97 insertions(+), 1 deletion(-)
 create mode 100644 net/mptcp/sched.c

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 4d761ad530c9..bea7608d72d3 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -95,6 +95,25 @@ struct mptcp_out_options {
 #endif
 };
 
+#define MPTCP_SCHED_NAME_MAX	16
+
+struct mptcp_sched_data {
+	struct sock	*sock;
+	bool		call_again;
+};
+
+struct mptcp_sched_ops {
+	void (*get_subflow)(struct mptcp_sock *msk, bool reinject,
+			    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
 extern struct request_sock_ops mptcp_subflow_request_sock_ops;
 
diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
index 6e7df47c9584..8a7f68efa35f 100644
--- 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
+	   mib.o pm_netlink.o sockopt.o pm_userspace.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 4672901d0dfe..221bb6b9860e 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -621,6 +621,9 @@ int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
 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 __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
 {
diff --git a/net/mptcp/sched.c b/net/mptcp/sched.c
new file mode 100644
index 000000000000..c5d3bbafba71
--- /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);
+}
diff --git a/tools/testing/selftests/bpf/bpf_mptcp_helpers.h b/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
index b5a43b108982..5b8eef4f1b4e 100644
--- a/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
@@ -6,6 +6,24 @@
 
 #include "bpf_tcp_helpers.h"
 
+#define MPTCP_SCHED_NAME_MAX	16
+
+struct mptcp_sched_data {
+	struct sock	*sock;
+	bool		call_again;
+};
+
+struct mptcp_sched_ops {
+	char name[MPTCP_SCHED_NAME_MAX];
+
+	void (*init)(struct mptcp_sock *msk);
+	void (*release)(struct mptcp_sock *msk);
+
+	void (*get_subflow)(struct mptcp_sock *msk, bool reinject,
+			    struct mptcp_sched_data *data);
+	void *owner;
+};
+
 struct mptcp_sock {
 	struct inet_connection_sock	sk;
 
-- 
2.34.1

[PATCH mptcp-next v18 2/7] mptcp: add a new sysctl scheduler

[Geliang Tang]

This patch adds a new sysctl, named scheduler, to support for selection
of different schedulers. Export mptcp_get_scheduler helper to get this
sysctl.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 Documentation/networking/mptcp-sysctl.rst |  8 ++++++++
 net/mptcp/ctrl.c                          | 14 ++++++++++++++
 net/mptcp/protocol.h                      |  1 +
 3 files changed, 23 insertions(+)

diff --git a/Documentation/networking/mptcp-sysctl.rst b/Documentation/networking/mptcp-sysctl.rst
index e263dfcc4b40..d9e69fdc7ea3 100644
--- a/Documentation/networking/mptcp-sysctl.rst
+++ b/Documentation/networking/mptcp-sysctl.rst
@@ -75,3 +75,11 @@ stale_loss_cnt - INTEGER
 	This is a per-namespace sysctl.
 
 	Default: 4
+
+scheduler - STRING
+	Select the scheduler of your choice.
+
+	Support for selection of different schedulers. This is a per-namespace
+	sysctl.
+
+	Default: "default"
diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c
index ae20b7d92e28..c46c22a84d23 100644
--- a/net/mptcp/ctrl.c
+++ b/net/mptcp/ctrl.c
@@ -32,6 +32,7 @@ struct mptcp_pernet {
 	u8 checksum_enabled;
 	u8 allow_join_initial_addr_port;
 	u8 pm_type;
+	char scheduler[MPTCP_SCHED_NAME_MAX];
 };
 
 static struct mptcp_pernet *mptcp_get_pernet(const struct net *net)
@@ -69,6 +70,11 @@ int mptcp_get_pm_type(const struct net *net)
 	return mptcp_get_pernet(net)->pm_type;
 }
 
+const char *mptcp_get_scheduler(const struct net *net)
+{
+	return mptcp_get_pernet(net)->scheduler;
+}
+
 static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
 {
 	pernet->mptcp_enabled = 1;
@@ -77,6 +83,7 @@ static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
 	pernet->allow_join_initial_addr_port = 1;
 	pernet->stale_loss_cnt = 4;
 	pernet->pm_type = MPTCP_PM_TYPE_KERNEL;
+	strcpy(pernet->scheduler, "default");
 }
 
 #ifdef CONFIG_SYSCTL
@@ -128,6 +135,12 @@ static struct ctl_table mptcp_sysctl_table[] = {
 		.extra1       = SYSCTL_ZERO,
 		.extra2       = &mptcp_pm_type_max
 	},
+	{
+		.procname = "scheduler",
+		.maxlen	= MPTCP_SCHED_NAME_MAX,
+		.mode = 0644,
+		.proc_handler = proc_dostring,
+	},
 	{}
 };
 
@@ -149,6 +162,7 @@ static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet)
 	table[3].data = &pernet->allow_join_initial_addr_port;
 	table[4].data = &pernet->stale_loss_cnt;
 	table[5].data = &pernet->pm_type;
+	table[6].data = &pernet->scheduler;
 
 	hdr = register_net_sysctl(net, MPTCP_SYSCTL_PATH, table);
 	if (!hdr)
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 221bb6b9860e..2f5ad12601cf 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -596,6 +596,7 @@ int mptcp_is_checksum_enabled(const struct net *net);
 int mptcp_allow_join_id0(const struct net *net);
 unsigned int mptcp_stale_loss_cnt(const struct net *net);
 int mptcp_get_pm_type(const struct net *net);
+const char *mptcp_get_scheduler(const struct net *net);
 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
 				     struct mptcp_options_received *mp_opt);
 bool __mptcp_retransmit_pending_data(struct sock *sk);
-- 
2.34.1

[PATCH mptcp-next v18 3/7] mptcp: add sched in mptcp_sock

[Geliang Tang]

This patch adds a new struct member sched in struct mptcp_sock.
And two helpers mptcp_init_sched() and mptcp_release_sched() to
init and release it.

Init it with the sysctl scheduler in mptcp_init_sock(), copy the
scheduler from the parent in mptcp_sk_clone(), and release it in
__mptcp_destroy_sock().

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/protocol.c                          |  7 ++++
 net/mptcp/protocol.h                          |  4 +++
 net/mptcp/sched.c                             | 33 +++++++++++++++++++
 .../testing/selftests/bpf/bpf_mptcp_helpers.h |  1 +
 4 files changed, 45 insertions(+)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 653757ea0aca..f599b702415e 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2665,6 +2665,11 @@ static int mptcp_init_sock(struct sock *sk)
 	if (ret)
 		return ret;
 
+	ret = mptcp_init_sched(mptcp_sk(sk),
+			       mptcp_sched_find(mptcp_get_scheduler(net)));
+	if (ret)
+		return ret;
+
 	/* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
 	 * propagate the correct value
 	 */
@@ -2824,6 +2829,7 @@ static void __mptcp_destroy_sock(struct sock *sk)
 	sk_stop_timer(sk, &sk->sk_timer);
 	mptcp_data_unlock(sk);
 	msk->pm.status = 0;
+	mptcp_release_sched(msk);
 
 	/* clears msk->subflow, allowing the following loop to close
 	 * even the initial subflow
@@ -3001,6 +3007,7 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
 	msk->snd_una = msk->write_seq;
 	msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;
 	msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
+	mptcp_init_sched(msk, mptcp_sk(sk)->sched);
 
 	if (mp_opt->suboptions & OPTIONS_MPTCP_MPC) {
 		msk->can_ack = true;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 2f5ad12601cf..723141a888f4 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -298,6 +298,7 @@ struct mptcp_sock {
 	struct socket	*subflow; /* outgoing connect/listener/!mp_capable */
 	struct sock	*first;
 	struct mptcp_pm_data	pm;
+	struct mptcp_sched_ops	*sched;
 	struct {
 		u32	space;	/* bytes copied in last measurement window */
 		u32	copied; /* bytes copied in this measurement window */
@@ -625,6 +626,9 @@ void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
 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);
+int mptcp_init_sched(struct mptcp_sock *msk,
+		     struct mptcp_sched_ops *sched);
+void mptcp_release_sched(struct mptcp_sock *msk);
 
 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
 {
diff --git a/net/mptcp/sched.c b/net/mptcp/sched.c
index c5d3bbafba71..53773668b5ee 100644
--- a/net/mptcp/sched.c
+++ b/net/mptcp/sched.c
@@ -54,3 +54,36 @@ void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched)
 	list_del_rcu(&sched->list);
 	spin_unlock(&mptcp_sched_list_lock);
 }
+
+int mptcp_init_sched(struct mptcp_sock *msk,
+		     struct mptcp_sched_ops *sched)
+{
+	if (!sched)
+		goto out;
+
+	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);
+
+out:
+	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);
+}
diff --git a/tools/testing/selftests/bpf/bpf_mptcp_helpers.h b/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
index 5b8eef4f1b4e..e863954de701 100644
--- a/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
@@ -29,6 +29,7 @@ struct mptcp_sock {
 
 	__u32		token;
 	struct sock	*first;
+	struct mptcp_sched_ops *sched;
 	char		ca_name[TCP_CA_NAME_MAX];
 } __attribute__((preserve_access_index));
 
-- 
2.34.1

[PATCH mptcp-next v18 4/7] mptcp: add get_subflow wrappers

[Geliang Tang]

This patch defines two new wrappers mptcp_sched_get_send() and
mptcp_sched_get_retrans(), invoke get_subflow() of msk->sched
in them. Use them instead of using mptcp_subflow_get_send() or
mptcp_subflow_get_retrans() directly.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/protocol.c | 25 +++++---------------
 net/mptcp/protocol.h |  2 ++
 net/mptcp/sched.c    | 54 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 19 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index f599b702415e..5243c58789a4 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1427,7 +1427,7 @@ bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
  * returns the subflow that will transmit the next DSS
  * additionally updates the rtx timeout
  */
-static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
+struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
 {
 	struct subflow_send_info send_info[SSK_MODE_MAX];
 	struct mptcp_subflow_context *subflow;
@@ -1438,14 +1438,6 @@ static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
 	u64 linger_time;
 	long tout = 0;
 
-	sock_owned_by_me(sk);
-
-	if (__mptcp_check_fallback(msk)) {
-		if (!msk->first)
-			return NULL;
-		return sk_stream_memory_free(msk->first) ? msk->first : NULL;
-	}
-
 	/* re-use last subflow, if the burst allow that */
 	if (msk->last_snd && msk->snd_burst > 0 &&
 	    sk_stream_memory_free(msk->last_snd) &&
@@ -1575,7 +1567,7 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
 			int ret = 0;
 
 			prev_ssk = ssk;
-			ssk = mptcp_subflow_get_send(msk);
+			ssk = mptcp_sched_get_send(msk);
 
 			/* First check. If the ssk has changed since
 			 * the last round, release prev_ssk
@@ -1644,7 +1636,7 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
 			 * check for a different subflow usage only after
 			 * spooling the first chunk of data
 			 */
-			xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk));
+			xmit_ssk = first ? ssk : mptcp_sched_get_send(mptcp_sk(sk));
 			if (!xmit_ssk)
 				goto out;
 			if (xmit_ssk != ssk) {
@@ -2218,17 +2210,12 @@ static void mptcp_timeout_timer(struct timer_list *t)
  *
  * A backup subflow is returned only if that is the only kind available.
  */
-static struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
+struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
 {
 	struct sock *backup = NULL, *pick = NULL;
 	struct mptcp_subflow_context *subflow;
 	int min_stale_count = INT_MAX;
 
-	sock_owned_by_me((const struct sock *)msk);
-
-	if (__mptcp_check_fallback(msk))
-		return NULL;
-
 	mptcp_for_each_subflow(msk, subflow) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 
@@ -2481,7 +2468,7 @@ static void __mptcp_retrans(struct sock *sk)
 	mptcp_clean_una_wakeup(sk);
 
 	/* first check ssk: need to kick "stale" logic */
-	ssk = mptcp_subflow_get_retrans(msk);
+	ssk = mptcp_sched_get_retrans(msk);
 	dfrag = mptcp_rtx_head(sk);
 	if (!dfrag) {
 		if (mptcp_data_fin_enabled(msk)) {
@@ -3146,7 +3133,7 @@ void __mptcp_check_push(struct sock *sk, struct sock *ssk)
 		return;
 
 	if (!sock_owned_by_user(sk)) {
-		struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk));
+		struct sock *xmit_ssk = mptcp_sched_get_send(mptcp_sk(sk));
 
 		if (xmit_ssk == ssk)
 			__mptcp_subflow_push_pending(sk, ssk);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 723141a888f4..fc5dca44470c 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -629,6 +629,8 @@ void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
 int mptcp_init_sched(struct mptcp_sock *msk,
 		     struct mptcp_sched_ops *sched);
 void mptcp_release_sched(struct mptcp_sock *msk);
+struct sock *mptcp_sched_get_send(struct mptcp_sock *msk);
+struct sock *mptcp_sched_get_retrans(struct mptcp_sock *msk);
 
 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
 {
diff --git a/net/mptcp/sched.c b/net/mptcp/sched.c
index 53773668b5ee..7a5654132ed3 100644
--- a/net/mptcp/sched.c
+++ b/net/mptcp/sched.c
@@ -15,6 +15,8 @@
 
 static DEFINE_SPINLOCK(mptcp_sched_list_lock);
 static LIST_HEAD(mptcp_sched_list);
+struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk);
+struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk);
 
 /* Must be called with rcu read lock held */
 struct mptcp_sched_ops *mptcp_sched_find(const char *name)
@@ -87,3 +89,55 @@ void mptcp_release_sched(struct mptcp_sock *msk)
 
 	bpf_module_put(sched, sched->owner);
 }
+
+static int mptcp_sched_data_init(struct mptcp_sock *msk,
+				 struct mptcp_sched_data *data)
+{
+	data->sock = NULL;
+	data->call_again = 0;
+
+	return 0;
+}
+
+struct sock *mptcp_sched_get_send(struct mptcp_sock *msk)
+{
+	struct mptcp_sched_data data;
+
+	sock_owned_by_me((struct sock *)msk);
+
+	/* the following check is moved out of mptcp_subflow_get_send */
+	if (__mptcp_check_fallback(msk)) {
+		if (!msk->first)
+			return NULL;
+		return sk_stream_memory_free(msk->first) ? msk->first : NULL;
+	}
+
+	if (!msk->sched)
+		return mptcp_subflow_get_send(msk);
+
+	mptcp_sched_data_init(msk, &data);
+	msk->sched->get_subflow(msk, false, &data);
+
+	msk->last_snd = data.sock;
+	return data.sock;
+}
+
+struct sock *mptcp_sched_get_retrans(struct mptcp_sock *msk)
+{
+	struct mptcp_sched_data data;
+
+	sock_owned_by_me((const struct sock *)msk);
+
+	/* the following check is moved out of mptcp_subflow_get_retrans */
+	if (__mptcp_check_fallback(msk))
+		return NULL;
+
+	if (!msk->sched)
+		return mptcp_subflow_get_retrans(msk);
+
+	mptcp_sched_data_init(msk, &data);
+	msk->sched->get_subflow(msk, true, &data);
+
+	msk->last_snd = data.sock;
+	return data.sock;
+}
-- 
2.34.1

[PATCH mptcp-next v18 5/7] mptcp: add bpf_mptcp_sched_ops

[Geliang Tang]

This patch implements a new struct bpf_struct_ops, bpf_mptcp_sched_ops.
Register and unregister the bpf scheduler in .reg and .unreg.

This MPTCP BPF scheduler implementation is similar to BPF TCP CC. And
net/ipv4/bpf_tcp_ca.c is a frame of reference for this patch.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 kernel/bpf/bpf_struct_ops_types.h |   4 +
 net/mptcp/bpf.c                   | 154 ++++++++++++++++++++++++++++++
 2 files changed, 158 insertions(+)

diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h
index 5678a9ddf817..5a6b0c0d8d3d 100644
--- a/kernel/bpf/bpf_struct_ops_types.h
+++ b/kernel/bpf/bpf_struct_ops_types.h
@@ -8,5 +8,9 @@ BPF_STRUCT_OPS_TYPE(bpf_dummy_ops)
 #ifdef CONFIG_INET
 #include <net/tcp.h>
 BPF_STRUCT_OPS_TYPE(tcp_congestion_ops)
+#ifdef CONFIG_MPTCP
+#include <net/mptcp.h>
+BPF_STRUCT_OPS_TYPE(mptcp_sched_ops)
+#endif
 #endif
 #endif
diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
index 535602ba2582..ad770deb5a72 100644
--- a/net/mptcp/bpf.c
+++ b/net/mptcp/bpf.c
@@ -10,8 +10,162 @@
 #define pr_fmt(fmt) "MPTCP: " fmt
 
 #include <linux/bpf.h>
+#include <linux/bpf_verifier.h>
+#include <linux/btf.h>
+#include <linux/btf_ids.h>
 #include "protocol.h"
 
+#ifdef CONFIG_BPF_JIT
+extern struct bpf_struct_ops bpf_mptcp_sched_ops;
+extern struct btf *btf_vmlinux;
+static const struct btf_type *mptcp_sched_type __read_mostly;
+static u32 mptcp_sched_id;
+
+static u32 optional_ops[] = {
+	offsetof(struct mptcp_sched_ops, init),
+	offsetof(struct mptcp_sched_ops, release),
+	offsetof(struct mptcp_sched_ops, get_subflow),
+};
+
+static const struct bpf_func_proto *
+bpf_mptcp_sched_get_func_proto(enum bpf_func_id func_id,
+			       const struct bpf_prog *prog)
+{
+	return bpf_base_func_proto(func_id);
+}
+
+static int bpf_mptcp_sched_btf_struct_access(struct bpf_verifier_log *log,
+					     const struct btf *btf,
+					     const struct btf_type *t, int off,
+					     int size, enum bpf_access_type atype,
+					     u32 *next_btf_id,
+					     enum bpf_type_flag *flag)
+{
+	size_t end;
+
+	if (atype == BPF_READ)
+		return btf_struct_access(log, btf, t, off, size, atype,
+					 next_btf_id, flag);
+
+	if (t != mptcp_sched_type) {
+		bpf_log(log, "only access to mptcp_sched_data is supported\n");
+		return -EACCES;
+	}
+
+	switch (off) {
+	case offsetof(struct mptcp_sched_data, sock):
+		end = offsetofend(struct mptcp_sched_data, sock);
+		break;
+	case offsetof(struct mptcp_sched_data, call_again):
+		end = offsetofend(struct mptcp_sched_data, call_again);
+		break;
+	default:
+		bpf_log(log, "no write support to mptcp_sched_data at off %d\n", off);
+		return -EACCES;
+	}
+
+	if (off + size > end) {
+		bpf_log(log, "access beyond mptcp_sched_data at off %u size %u ended at %zu",
+			off, size, end);
+		return -EACCES;
+	}
+
+	return NOT_INIT;
+}
+
+static const struct bpf_verifier_ops bpf_mptcp_sched_verifier_ops = {
+	.get_func_proto		= bpf_mptcp_sched_get_func_proto,
+	.is_valid_access	= bpf_tracing_btf_ctx_access,
+	.btf_struct_access	= bpf_mptcp_sched_btf_struct_access,
+};
+
+static int bpf_mptcp_sched_reg(void *kdata)
+{
+	return mptcp_register_scheduler(kdata);
+}
+
+static void bpf_mptcp_sched_unreg(void *kdata)
+{
+	mptcp_unregister_scheduler(kdata);
+}
+
+static int bpf_mptcp_sched_check_member(const struct btf_type *t,
+					const struct btf_member *member)
+{
+	return 0;
+}
+
+static bool is_optional(u32 member_offset)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(optional_ops); i++) {
+		if (member_offset == optional_ops[i])
+			return true;
+	}
+
+	return false;
+}
+
+static int bpf_mptcp_sched_init_member(const struct btf_type *t,
+				       const struct btf_member *member,
+				       void *kdata, const void *udata)
+{
+	const struct mptcp_sched_ops *usched;
+	struct mptcp_sched_ops *sched;
+	int prog_fd;
+	u32 moff;
+
+	usched = (const struct mptcp_sched_ops *)udata;
+	sched = (struct mptcp_sched_ops *)kdata;
+
+	moff = __btf_member_bit_offset(t, member) / 8;
+	switch (moff) {
+	case offsetof(struct mptcp_sched_ops, name):
+		if (bpf_obj_name_cpy(sched->name, usched->name,
+				     sizeof(sched->name)) <= 0)
+			return -EINVAL;
+		if (mptcp_sched_find(usched->name))
+			return -EEXIST;
+		return 1;
+	}
+
+	if (!btf_type_resolve_func_ptr(btf_vmlinux, member->type, NULL))
+		return 0;
+
+	/* Ensure bpf_prog is provided for compulsory func ptr */
+	prog_fd = (int)(*(unsigned long *)(udata + moff));
+	if (!prog_fd && !is_optional(moff))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int bpf_mptcp_sched_init(struct btf *btf)
+{
+	s32 type_id;
+
+	type_id = btf_find_by_name_kind(btf, "mptcp_sched_data",
+					BTF_KIND_STRUCT);
+	if (type_id < 0)
+		return -EINVAL;
+	mptcp_sched_id = type_id;
+	mptcp_sched_type = btf_type_by_id(btf, mptcp_sched_id);
+
+	return 0;
+}
+
+struct bpf_struct_ops bpf_mptcp_sched_ops = {
+	.verifier_ops	= &bpf_mptcp_sched_verifier_ops,
+	.reg		= bpf_mptcp_sched_reg,
+	.unreg		= bpf_mptcp_sched_unreg,
+	.check_member	= bpf_mptcp_sched_check_member,
+	.init_member	= bpf_mptcp_sched_init_member,
+	.init		= bpf_mptcp_sched_init,
+	.name		= "mptcp_sched_ops",
+};
+#endif /* CONFIG_BPF_JIT */
+
 struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk)
 {
 	if (sk && sk_fullsock(sk) && sk->sk_protocol == IPPROTO_TCP && sk_is_mptcp(sk))
-- 
2.34.1

[PATCH mptcp-next v18 6/7] selftests: bpf: add bpf_first scheduler

[Geliang Tang]

This patch implements the simplest MPTCP scheduler, named bpf_first,
which always picks the first subflow to send data. It's a sample of
MPTCP BPF scheduler implementations.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 .../selftests/bpf/progs/mptcp_bpf_first.c     | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/mptcp_bpf_first.c

diff --git a/tools/testing/selftests/bpf/progs/mptcp_bpf_first.c b/tools/testing/selftests/bpf/progs/mptcp_bpf_first.c
new file mode 100644
index 000000000000..0ca9754c078d
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/mptcp_bpf_first.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022, SUSE. */
+
+#include <linux/bpf.h>
+#include "bpf_mptcp_helpers.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("struct_ops/mptcp_sched_first_init")
+void BPF_PROG(mptcp_sched_first_init, struct mptcp_sock *msk)
+{
+}
+
+SEC("struct_ops/mptcp_sched_first_release")
+void BPF_PROG(mptcp_sched_first_release, struct mptcp_sock *msk)
+{
+}
+
+void BPF_STRUCT_OPS(bpf_first_get_subflow, struct mptcp_sock *msk,
+		    bool reinject, struct mptcp_sched_data *data)
+{
+	data->sock = msk->first;
+	data->call_again = 0;
+}
+
+SEC(".struct_ops")
+struct mptcp_sched_ops first = {
+	.init		= (void *)mptcp_sched_first_init,
+	.release	= (void *)mptcp_sched_first_release,
+	.get_subflow	= (void *)bpf_first_get_subflow,
+	.name		= "bpf_first",
+};
-- 
2.34.1

[PATCH mptcp-next v18 7/7] selftests: bpf: add bpf_first test

[Geliang Tang]

This patch expends the MPTCP test base to support MPTCP packet
scheduler tests. Add the bpf_first scheduler test in it. Use sysctl
to set net.mptcp.scheduler to use this sched.

Some code in send_data() is from prog_tests/bpf_tcp_ca.c.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 .../testing/selftests/bpf/prog_tests/mptcp.c  | 112 ++++++++++++++++++
 1 file changed, 112 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
index ed5773c26045..21462c29683c 100644
--- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -4,6 +4,7 @@
 #include <test_progs.h>
 #include "cgroup_helpers.h"
 #include "network_helpers.h"
+#include "mptcp_bpf_first.skel.h"
 
 #ifndef TCP_CA_NAME_MAX
 #define TCP_CA_NAME_MAX	16
@@ -19,6 +20,8 @@ struct mptcp_storage {
 };
 
 static char monitor_log_path[64];
+static const unsigned int total_bytes = 10 * 1024 * 1024;
+static int stop, duration;
 
 static int verify_tsk(int map_fd, int client_fd)
 {
@@ -265,8 +268,117 @@ void test_base(void)
 	close(cgroup_fd);
 }
 
+static void *server(void *arg)
+{
+	int lfd = (int)(long)arg, err = 0, fd;
+	ssize_t nr_sent = 0, bytes = 0;
+	char batch[1500];
+
+	fd = accept(lfd, NULL, NULL);
+	while (fd == -1) {
+		if (errno == EINTR)
+			continue;
+		err = -errno;
+		goto done;
+	}
+
+	if (settimeo(fd, 0)) {
+		err = -errno;
+		goto done;
+	}
+
+	while (bytes < total_bytes && !READ_ONCE(stop)) {
+		nr_sent = send(fd, &batch,
+			       MIN(total_bytes - bytes, sizeof(batch)), 0);
+		if (nr_sent == -1 && errno == EINTR)
+			continue;
+		if (nr_sent == -1) {
+			err = -errno;
+			break;
+		}
+		bytes += nr_sent;
+	}
+
+	CHECK(bytes != total_bytes, "send", "%zd != %u nr_sent:%zd errno:%d\n",
+	      bytes, total_bytes, nr_sent, errno);
+
+done:
+	if (fd >= 0)
+		close(fd);
+	if (err) {
+		WRITE_ONCE(stop, 1);
+		return ERR_PTR(err);
+	}
+	return NULL;
+}
+
+static void send_data(int lfd, int fd)
+{
+	ssize_t nr_recv = 0, bytes = 0;
+	pthread_t srv_thread;
+	void *thread_ret;
+	char batch[1500];
+	int err;
+
+	WRITE_ONCE(stop, 0);
+
+	err = pthread_create(&srv_thread, NULL, server, (void *)(long)lfd);
+	if (CHECK(err != 0, "pthread_create", "err:%d errno:%d\n", err, errno))
+		return;
+
+	/* recv total_bytes */
+	while (bytes < total_bytes && !READ_ONCE(stop)) {
+		nr_recv = recv(fd, &batch,
+			       MIN(total_bytes - bytes, sizeof(batch)), 0);
+		if (nr_recv == -1 && errno == EINTR)
+			continue;
+		if (nr_recv == -1)
+			break;
+		bytes += nr_recv;
+	}
+
+	CHECK(bytes != total_bytes, "recv", "%zd != %u nr_recv:%zd errno:%d\n",
+	      bytes, total_bytes, nr_recv, errno);
+
+	WRITE_ONCE(stop, 1);
+
+	pthread_join(srv_thread, &thread_ret);
+	CHECK(IS_ERR(thread_ret), "pthread_join", "thread_ret:%ld",
+	      PTR_ERR(thread_ret));
+}
+
+static void test_first(void)
+{
+	struct mptcp_bpf_first *first_skel;
+	int server_fd, client_fd;
+	struct bpf_link *link;
+
+	first_skel = mptcp_bpf_first__open_and_load();
+	if (CHECK(!first_skel, "bpf_first__open_and_load", "failed\n"))
+		return;
+
+	link = bpf_map__attach_struct_ops(first_skel->maps.first);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops")) {
+		mptcp_bpf_first__destroy(first_skel);
+		return;
+	}
+
+	system("sysctl -q net.mptcp.scheduler=bpf_first");
+	server_fd = start_mptcp_server(AF_INET, NULL, 0, 0);
+	client_fd = connect_to_mptcp_fd(server_fd, 0);
+
+	send_data(server_fd, client_fd);
+
+	close(client_fd);
+	close(server_fd);
+	bpf_link__destroy(link);
+	mptcp_bpf_first__destroy(first_skel);
+}
+
 void test_mptcp(void)
 {
 	if (test__start_subtest("base"))
 		test_base();
+	if (test__start_subtest("first"))
+		test_first();
 }
-- 
2.34.1

Re: selftests: bpf: add bpf_first test: Build Failure

[MPTCP CI]

Hi Geliang,

Thank you for your modifications, that's great!

But sadly, our CI spotted some issues with it when trying to build it.

You can find more details there:

  https://patchwork.kernel.org/project/mptcp/patch/2c5bd5067e0d508dc5e677da3848d6aa6f610174.1651412613.git.geliang.tang@suse.com/
  https://github.com/multipath-tcp/mptcp_net-next/actions/runs/2253717943

Status: failure
Initiator: MPTCPimporter
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/cfcd857eaf69

Feel free to reply to this email if you cannot access logs, if you need
some support to fix the error, if this doesn't seem to be caused by your
modifications or if the error is a false positive one.

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (Tessares)

Re: selftests: bpf: add bpf_first test: Tests Results

[MPTCP CI]

Hi Geliang,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal:
  - Unstable: 2 failed test(s): packetdrill_add_addr selftest_simult_flows 🔴:
  - Task: https://cirrus-ci.com/task/5827059619463168
  - Summary: https://api.cirrus-ci.com/v1/artifact/task/5827059619463168/summary/summary.txt

- KVM Validation: debug:
  - Unstable: 1 failed test(s): selftest_diag - Critical: 1 Call Trace(s) ❌:
  - Task: https://cirrus-ci.com/task/5264109666041856
  - Summary: https://api.cirrus-ci.com/v1/artifact/task/5264109666041856/summary/summary.txt

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/cfcd857eaf69


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-debug

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (Tessares)

Re: [PATCH mptcp-next v18 5/7] mptcp: add bpf_mptcp_sched_ops

[Paolo Abeni]

Hello,

On Sun, 2022-05-01 at 21:48 +0800, Geliang Tang wrote:
> This patch implements a new struct bpf_struct_ops, bpf_mptcp_sched_ops.
> Register and unregister the bpf scheduler in .reg and .unreg.
> 
> This MPTCP BPF scheduler implementation is similar to BPF TCP CC. And
> net/ipv4/bpf_tcp_ca.c is a frame of reference for this patch.
> 
> Signed-off-by: Geliang Tang <geliang.tang@suse.com>
> ---
>  kernel/bpf/bpf_struct_ops_types.h |   4 +
>  net/mptcp/bpf.c                   | 154 ++++++++++++++++++++++++++++++
>  2 files changed, 158 insertions(+)
> 
> diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h
> index 5678a9ddf817..5a6b0c0d8d3d 100644
> --- a/kernel/bpf/bpf_struct_ops_types.h
> +++ b/kernel/bpf/bpf_struct_ops_types.h
> @@ -8,5 +8,9 @@ BPF_STRUCT_OPS_TYPE(bpf_dummy_ops)
>  #ifdef CONFIG_INET
>  #include <net/tcp.h>
>  BPF_STRUCT_OPS_TYPE(tcp_congestion_ops)
> +#ifdef CONFIG_MPTCP
> +#include <net/mptcp.h>
> +BPF_STRUCT_OPS_TYPE(mptcp_sched_ops)
> +#endif
>  #endif
>  #endif
> diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
> index 535602ba2582..ad770deb5a72 100644
> --- a/net/mptcp/bpf.c
> +++ b/net/mptcp/bpf.c
> @@ -10,8 +10,162 @@
>  #define pr_fmt(fmt) "MPTCP: " fmt
>  
>  #include <linux/bpf.h>
> +#include <linux/bpf_verifier.h>
> +#include <linux/btf.h>
> +#include <linux/btf_ids.h>
>  #include "protocol.h"
>  
> +#ifdef CONFIG_BPF_JIT
> +extern struct bpf_struct_ops bpf_mptcp_sched_ops;
> +extern struct btf *btf_vmlinux;
> +static const struct btf_type *mptcp_sched_type __read_mostly;
> +static u32 mptcp_sched_id;
> +
> +static u32 optional_ops[] = {
> +	offsetof(struct mptcp_sched_ops, init),
> +	offsetof(struct mptcp_sched_ops, release),
> +	offsetof(struct mptcp_sched_ops, get_subflow),

I think that the 'get_subflow' member should not be options. Otherwise
the scheduler will useless, right ?!?

Otherwise LGTM.

Thanks!

Paolo

Re: [PATCH mptcp-next v18 5/7] mptcp: add bpf_mptcp_sched_ops

[Mat Martineau]

On Mon, 2 May 2022, Paolo Abeni wrote:

> Hello,
>
> On Sun, 2022-05-01 at 21:48 +0800, Geliang Tang wrote:
>> This patch implements a new struct bpf_struct_ops, bpf_mptcp_sched_ops.
>> Register and unregister the bpf scheduler in .reg and .unreg.
>>
>> This MPTCP BPF scheduler implementation is similar to BPF TCP CC. And
>> net/ipv4/bpf_tcp_ca.c is a frame of reference for this patch.
>>
>> Signed-off-by: Geliang Tang <geliang.tang@suse.com>
>> ---
>>  kernel/bpf/bpf_struct_ops_types.h |   4 +
>>  net/mptcp/bpf.c                   | 154 ++++++++++++++++++++++++++++++
>>  2 files changed, 158 insertions(+)
>>
>> diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h
>> index 5678a9ddf817..5a6b0c0d8d3d 100644
>> --- a/kernel/bpf/bpf_struct_ops_types.h
>> +++ b/kernel/bpf/bpf_struct_ops_types.h
>> @@ -8,5 +8,9 @@ BPF_STRUCT_OPS_TYPE(bpf_dummy_ops)
>>  #ifdef CONFIG_INET
>>  #include <net/tcp.h>
>>  BPF_STRUCT_OPS_TYPE(tcp_congestion_ops)
>> +#ifdef CONFIG_MPTCP
>> +#include <net/mptcp.h>
>> +BPF_STRUCT_OPS_TYPE(mptcp_sched_ops)
>> +#endif
>>  #endif
>>  #endif
>> diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
>> index 535602ba2582..ad770deb5a72 100644
>> --- a/net/mptcp/bpf.c
>> +++ b/net/mptcp/bpf.c
>> @@ -10,8 +10,162 @@
>>  #define pr_fmt(fmt) "MPTCP: " fmt
>>
>>  #include <linux/bpf.h>
>> +#include <linux/bpf_verifier.h>
>> +#include <linux/btf.h>
>> +#include <linux/btf_ids.h>
>>  #include "protocol.h"
>>
>> +#ifdef CONFIG_BPF_JIT
>> +extern struct bpf_struct_ops bpf_mptcp_sched_ops;
>> +extern struct btf *btf_vmlinux;
>> +static const struct btf_type *mptcp_sched_type __read_mostly;
>> +static u32 mptcp_sched_id;
>> +
>> +static u32 optional_ops[] = {
>> +	offsetof(struct mptcp_sched_ops, init),
>> +	offsetof(struct mptcp_sched_ops, release),
>> +	offsetof(struct mptcp_sched_ops, get_subflow),
>
> I think that the 'get_subflow' member should not be options. Otherwise
> the scheduler will useless, right ?!?
>
> Otherwise LGTM.
>

I agree - for this series (with the squashed get_subflow fix), looks good:

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>

--
Mat Martineau
Intel

Re: [PATCH mptcp-next v18 0/7] BPF packet scheduler

[Matthieu Baerts]

Hi Geliang, Mat, Paolo,

On 01/05/2022 15:48, Geliang Tang wrote:
> v18:
>  - drop "mptcp: add last_snd write access".
>  - add mptcp_sched_data_init helper.
>  - move mptcp_sched_get_send() and mptcp_sched_get_retrans() into sched.c.

Thank you for the patches and reviews!

Now in our tree (feat. for others) with Paolo's ACK and Mat's RvB tags:

New patches for t/upstream:
- 2d934cabfc25: mptcp: add struct mptcp_sched_ops
- 467bf7c54c40: mptcp: add a new sysctl scheduler
- 9281e21f5f4d: mptcp: add sched in mptcp_sock
- 656ddb9db4e1: mptcp: add get_subflow wrappers
- be9de4168364: mptcp: add bpf_mptcp_sched_ops
- 2885b934b680: selftests: bpf: add bpf_first scheduler
- 0201204572f8: selftests: bpf: add bpf_first test
- Results: bea7cea0ffcd..9d8bf95bd8a7 (export)

And the squash-to patches:

- d8a1213416ef: "squashed" in "mptcp: add get_subflow wrappers"
- Results: 9d8bf95bd8a7..4c418cbad090 (export)

- 014d79843c44: "squashed" in "mptcp: add bpf_mptcp_sched_ops"
- Results: 4c418cbad090..aa6bec3f788f (export)

- 3b8d5a354bf6: "squashed" in "mptcp: add struct mptcp_sched_ops"
- Results: aa6bec3f788f..527315ca1901 (export)

- 92b309479c5c: "squashed" in "selftests: bpf: add bpf_first scheduler"
- Results: 527315ca1901..a800c43a02ab (export)

- 35a824bb888a: "squashed" in "selftests: bpf: add bpf_first test"
- Results: a800c43a02ab..c3f5d94e8dc4 (export)


Builds and tests are now in progress:

https://cirrus-ci.com/github/multipath-tcp/mptcp_net-next/export/20220503T162811
https://github.com/multipath-tcp/mptcp_net-next/actions/workflows/build-validation.yml?query=branch:export


> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/75

I didn't close it because "BPF round-robin scheduler" series also closes it.

Cheers,
Matt
-- 
Tessares | Belgium | Hybrid Access Solutions
www.tessares.net