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[PATCH mptcp-next v5 2/7] mptcp: pm: add accept_new_subflow() interface

Geliang Tang posted 7 patches 2 weeks, 1 day ago
There is a newer version of this series
[PATCH mptcp-next v5 2/7] mptcp: pm: add accept_new_subflow() interface
Posted by Geliang Tang 2 weeks, 1 day ago 
From: Geliang Tang <tanggeliang@kylinos.cn>

The helper mptcp_pm_is_userspace() is used to distinguish userspace PM
operations from in-kernel PM in mptcp_can_accept_new_subflow(). It seems
reasonable to add a mandatory .accept_new_subflow interface for struct
mptcp_pm_ops.

The boolean type 'allow' parameter is used to control whether to allow new
subflow unconditionally.

A new helper mptcp_pm_accept_new_subflow() is added in pm.c to ensure that
pm->ops is only used in pm.c.

This interface of the in-kernel PM is implemented as a wrapper of
READ_ONCE(pm->accept_subflow), and this interface of the userspace PM is
implemented as a wrapper of mptcp_userspace_pm_active().

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 include/net/mptcp.h      |  1 +
 net/mptcp/pm.c           |  8 +++++++-
 net/mptcp/pm_kernel.c    | 15 +++++++++++++++
 net/mptcp/pm_userspace.c |  7 +++++++
 net/mptcp/protocol.h     |  1 +
 net/mptcp/subflow.c      |  6 ++----
 6 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 4cf59e83c1c5..549b8075cc86 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -123,6 +123,7 @@ struct mptcp_pm_ops {
 			    struct mptcp_pm_addr_entry *skc);
 	bool (*get_priority)(struct mptcp_sock *msk,
 			     struct mptcp_addr_info *skc);
+	bool (*accept_new_subflow)(struct mptcp_sock *msk, bool allow);
 
 	char			name[MPTCP_PM_NAME_MAX];
 	struct module		*owner;
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index be1e27ee393e..1c8395d3baa9 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -453,6 +453,11 @@ void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int
 	mptcp_event(MPTCP_EVENT_CREATED, msk, ssk, GFP_ATOMIC);
 }
 
+bool mptcp_pm_accept_new_subflow(struct mptcp_sock *msk, bool allow)
+{
+	return msk->pm.ops->accept_new_subflow(msk, allow);
+}
+
 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
 {
 	struct mptcp_pm_data *pm = &msk->pm;
@@ -1050,7 +1055,8 @@ struct mptcp_pm_ops *mptcp_pm_find(const char *name)
 
 int mptcp_pm_validate(struct mptcp_pm_ops *pm_ops)
 {
-	if (!pm_ops->get_local_id || !pm_ops->get_priority) {
+	if (!pm_ops->get_local_id || !pm_ops->get_priority ||
+	    !pm_ops->accept_new_subflow) {
 		pr_err("%s does not implement required ops\n", pm_ops->name);
 		return -EINVAL;
 	}
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 7ec81d5195d4..ee3915d33e04 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -1399,6 +1399,20 @@ static struct pernet_operations mptcp_pm_pernet_ops = {
 	.size = sizeof(struct pm_nl_pernet),
 };
 
+static bool mptcp_pm_kernel_accept_new_subflow(struct mptcp_sock *msk,
+					       bool allow)
+{
+	struct mptcp_pm_data *pm = &msk->pm;
+	bool ret = false;
+
+	if (READ_ONCE(pm->accept_subflow)) {
+		if (allow)
+			return true;
+	}
+
+	return ret;
+}
+
 static void mptcp_pm_kernel_init(struct mptcp_sock *msk)
 {
 	bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
@@ -1422,6 +1436,7 @@ static void mptcp_pm_kernel_init(struct mptcp_sock *msk)
 struct mptcp_pm_ops mptcp_pm_kernel = {
 	.get_local_id		= mptcp_pm_kernel_get_local_id,
 	.get_priority		= mptcp_pm_kernel_get_priority,
+	.accept_new_subflow	= mptcp_pm_kernel_accept_new_subflow,
 	.init			= mptcp_pm_kernel_init,
 	.name			= "kernel",
 	.owner			= THIS_MODULE,
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index 7fc19b844384..c6f67c5e2353 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -683,6 +683,12 @@ int mptcp_userspace_pm_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,
 	return ret;
 }
 
+static bool mptcp_pm_userspace_accept_new_subflow(struct mptcp_sock *msk,
+						  bool allow)
+{
+	return mptcp_userspace_pm_active(msk);
+}
+
 static void mptcp_pm_userspace_release(struct mptcp_sock *msk)
 {
 	mptcp_userspace_pm_free_local_addr_list(msk);
@@ -691,6 +697,7 @@ static void mptcp_pm_userspace_release(struct mptcp_sock *msk)
 static struct mptcp_pm_ops mptcp_pm_userspace = {
 	.get_local_id		= mptcp_pm_userspace_get_local_id,
 	.get_priority		= mptcp_pm_userspace_get_priority,
+	.accept_new_subflow	= mptcp_pm_userspace_accept_new_subflow,
 	.release		= mptcp_pm_userspace_release,
 	.name			= "userspace",
 	.owner			= THIS_MODULE,
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 64aa091cb685..6d1d57beb5d3 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1008,6 +1008,7 @@ bool mptcp_pm_addr_families_match(const struct sock *sk,
 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
+bool mptcp_pm_accept_new_subflow(struct mptcp_sock *msk, bool allow);
 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 409bd415ef1d..b13a679bdf05 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -58,12 +58,10 @@ static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
 	mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
 }
 
-static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk)
+static bool mptcp_can_accept_new_subflow(struct mptcp_sock *msk)
 {
 	return mptcp_is_fully_established((void *)msk) &&
-		((mptcp_pm_is_userspace(msk) &&
-		  mptcp_userspace_pm_active(msk)) ||
-		 READ_ONCE(msk->pm.accept_subflow));
+		mptcp_pm_accept_new_subflow(msk, true);
 }
 
 /* validate received token and create truncated hmac and nonce for SYN-ACK */
-- 
2.43.0
Re: [PATCH mptcp-next v5 2/7] mptcp: pm: add accept_new_subflow() interface
Posted by Matthieu Baerts 2 weeks, 1 day ago 
Hi Geliang,

On 27/03/2025 07:04, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> The helper mptcp_pm_is_userspace() is used to distinguish userspace PM
> operations from in-kernel PM in mptcp_can_accept_new_subflow(). It seems
> reasonable to add a mandatory .accept_new_subflow interface for struct
> mptcp_pm_ops.
> 
> The boolean type 'allow' parameter is used to control whether to allow new
> subflow unconditionally.
> 
> A new helper mptcp_pm_accept_new_subflow() is added in pm.c to ensure that
> pm->ops is only used in pm.c.
> 
> This interface of the in-kernel PM is implemented as a wrapper of
> READ_ONCE(pm->accept_subflow), and this interface of the userspace PM is
> implemented as a wrapper of mptcp_userspace_pm_active().
> 
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
>  include/net/mptcp.h      |  1 +
>  net/mptcp/pm.c           |  8 +++++++-
>  net/mptcp/pm_kernel.c    | 15 +++++++++++++++
>  net/mptcp/pm_userspace.c |  7 +++++++
>  net/mptcp/protocol.h     |  1 +
>  net/mptcp/subflow.c      |  6 ++----
>  6 files changed, 33 insertions(+), 5 deletions(-)
> 
> diff --git a/include/net/mptcp.h b/include/net/mptcp.h
> index 4cf59e83c1c5..549b8075cc86 100644
> --- a/include/net/mptcp.h
> +++ b/include/net/mptcp.h
> @@ -123,6 +123,7 @@ struct mptcp_pm_ops {
>  			    struct mptcp_pm_addr_entry *skc);
>  	bool (*get_priority)(struct mptcp_sock *msk,
>  			     struct mptcp_addr_info *skc);
> +	bool (*accept_new_subflow)(struct mptcp_sock *msk, bool allow);
>  
>  	char			name[MPTCP_PM_NAME_MAX];
>  	struct module		*owner;
> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
> index be1e27ee393e..1c8395d3baa9 100644
> --- a/net/mptcp/pm.c
> +++ b/net/mptcp/pm.c
> @@ -453,6 +453,11 @@ void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int
>  	mptcp_event(MPTCP_EVENT_CREATED, msk, ssk, GFP_ATOMIC);
>  }
>  
> +bool mptcp_pm_accept_new_subflow(struct mptcp_sock *msk, bool allow)
> +{
> +	return msk->pm.ops->accept_new_subflow(msk, allow);
> +}
> +
>  bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
>  {
>  	struct mptcp_pm_data *pm = &msk->pm;
> @@ -1050,7 +1055,8 @@ struct mptcp_pm_ops *mptcp_pm_find(const char *name)
>  
>  int mptcp_pm_validate(struct mptcp_pm_ops *pm_ops)
>  {
> -	if (!pm_ops->get_local_id || !pm_ops->get_priority) {
> +	if (!pm_ops->get_local_id || !pm_ops->get_priority ||
> +	    !pm_ops->accept_new_subflow) {
>  		pr_err("%s does not implement required ops\n", pm_ops->name);
>  		return -EINVAL;
>  	}
> diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
> index 7ec81d5195d4..ee3915d33e04 100644
> --- a/net/mptcp/pm_kernel.c
> +++ b/net/mptcp/pm_kernel.c
> @@ -1399,6 +1399,20 @@ static struct pernet_operations mptcp_pm_pernet_ops = {
>  	.size = sizeof(struct pm_nl_pernet),
>  };
>  
> +static bool mptcp_pm_kernel_accept_new_subflow(struct mptcp_sock *msk,
> +					       bool allow)

"allow" is always true.

> +{
> +	struct mptcp_pm_data *pm = &msk->pm;
> +	bool ret = false;
> +
> +	if (READ_ONCE(pm->accept_subflow)) {
> +		if (allow)
> +			return true;
> +	}
> +
> +	return ret;

Mmh, what about:

  return READ_ONCE(msk->pm.accept_subflow) && allow;

EDIT: OK, I just noticed the next patch. I suggest squashing this patch
with the next one, or you remove 'allow' and simplify this code here,
but I think it is easier to squash.

Cheers,
Matt
-- 
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