Add the address into userspace_pm_local_addr_list when the subflow is
created. Make sure it can be found in mptcp_nl_cmd_remove(). And delete
it in the new helper mptcp_userspace_pm_delete_local_addr().

Fixes: d9a4594edabf ("mptcp: netlink: Add MPTCP_PM_CMD_REMOVE")
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/379
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/pm_userspace.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index 6beadea8c67d..fc96405b7616 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -79,6 +79,22 @@ static int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 	return ret;
 }
 
+static int mptcp_userspace_pm_delete_local_addr(struct mptcp_sock *msk,
+						struct mptcp_pm_addr_entry *addr)
+{
+	struct mptcp_pm_addr_entry *entry, *tmp;
+
+	list_for_each_entry_safe(entry, tmp, &msk->pm.userspace_pm_local_addr_list, list) {
+		if (mptcp_addresses_equal(&entry->addr, &addr->addr, false)) {
+			list_del_rcu(&entry->list);
+			kfree(entry);
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
 						   unsigned int id,
 						   u8 *flags, int *ifindex)
@@ -251,6 +267,7 @@ int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info)
 	struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
 	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
 	struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	struct mptcp_pm_addr_entry local = { 0 };
 	struct mptcp_addr_info addr_r;
 	struct mptcp_addr_info addr_l;
 	struct mptcp_sock *msk;
@@ -302,12 +319,25 @@ int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info)
 		goto create_err;
 	}
 
+	local.addr = addr_l;
+	err = mptcp_userspace_pm_append_new_local_addr(msk, &local);
+	if (err < 0) {
+		GENL_SET_ERR_MSG(info, "did not match address and id");
+		goto create_err;
+	}
+
 	lock_sock(sk);
 
 	err = __mptcp_subflow_connect(sk, &addr_l, &addr_r);
 
 	release_sock(sk);
 
+	if (err) {
+		spin_lock_bh(&msk->pm.lock);
+		mptcp_userspace_pm_delete_local_addr(msk, &local);
+		spin_unlock_bh(&msk->pm.lock);
+	}
+
  create_err:
 	sock_put((struct sock *)msk);
 	return err;
@@ -420,10 +450,14 @@ int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info)
 	ssk = mptcp_nl_find_ssk(msk, &addr_l, &addr_r);
 	if (ssk) {
 		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+		struct mptcp_pm_addr_entry entry = { .addr = addr_l };
 
 		mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN | SEND_SHUTDOWN);
 		mptcp_close_ssk(sk, ssk, subflow);
 		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMSUBFLOW);
+		spin_lock_bh(&msk->pm.lock);
+		mptcp_userspace_pm_delete_local_addr(msk, &entry);
+		spin_unlock_bh(&msk->pm.lock);
 		err = 0;
 	} else {
 		err = -ESRCH;
-- 
2.35.3

Hi Geliang,

On 26/04/2023 10:56, Geliang Tang wrote:
> Add the address into userspace_pm_local_addr_list when the subflow is
> created. Make sure it can be found in mptcp_nl_cmd_remove(). And delete
> it in the new helper mptcp_userspace_pm_delete_local_addr().
> 
> Fixes: d9a4594edabf ("mptcp: netlink: Add MPTCP_PM_CMD_REMOVE")
> Link: https://github.com/multipath-tcp/mptcp_net-next/issues/379
> Signed-off-by: Geliang Tang <geliang.tang@suse.com>
> ---
>  net/mptcp/pm_userspace.c | 34 ++++++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 
> diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
> index 6beadea8c67d..fc96405b7616 100644
> --- a/net/mptcp/pm_userspace.c
> +++ b/net/mptcp/pm_userspace.c
> @@ -79,6 +79,22 @@ static int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
>  	return ret;
>  }
>  

Regarding my question from the v9 about removing the local addr if the
subflow is closed from the other peer (not via a subflow destroy command
then), do we want to keep the entry not to assign the same ID to another
address and/or to be able to send RM_ADDR after the removal of the
subflow? If yes, it would be good to add a comment here in the code
about that I think, no?

> +static int mptcp_userspace_pm_delete_local_addr(struct mptcp_sock *msk,
> +						struct mptcp_pm_addr_entry *addr)
> +{
> +	struct mptcp_pm_addr_entry *entry, *tmp;
> +
> +	list_for_each_entry_safe(entry, tmp, &msk->pm.userspace_pm_local_addr_list, list) {
> +		if (mptcp_addresses_equal(&entry->addr, &addr->addr, false)) {

I think we should add a TODO comment here to say that a refcount is
needed because the entry can be used multiple times (e.g. fullmesh mode)
and/or create a new ticket. Except if you are already working on that?

> +			list_del_rcu(&entry->list);
> +			kfree(entry);
> +			return 0;
> +		}
> +	}

Cheers,
Matt
-- 
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