[MPTCP] Re: [MPTCP][PATCH v2 mptcp-next 1/4] mptcp: move to next addr when subflow creation fail

[Mat Martineau <mathew.j.martineau at linux.intel.com>]

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On Mon, 8 Feb 2021, Geliang Tang wrote:

> When an invalid address was announced, the subflow couldn't be created
> for this address. Therefore mptcp_pm_nl_subflow_established couldn't be
> invoked. Then the next addresses in the local address list didn't have a
> chance to be announced.
>
> This patch invokes the new function mptcp_pm_add_addr_echoed when the
> address is echoed. In it, use lookup_subflow_by_saddr to check whether
> this address is in the conn_list. If it isn't, PM schedule the new
> status MPTCP_PM_NEXT_ADDR to invoke mptcp_pm_nl_next_addr.
>
> In mptcp_pm_nl_next_addr, invoke mptcp_pm_create_subflow_or_signal_addr
> to deal with the next address in the local address list.
>
> Signed-off-by: Geliang Tang <geliangtang(a)gmail.com>
> ---
> net/mptcp/options.c    |  1 +
> net/mptcp/pm.c         | 15 +++++++++++++++
> net/mptcp/pm_netlink.c | 13 +++++++++++--
> net/mptcp/protocol.h   |  4 ++++
> 4 files changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/net/mptcp/options.c b/net/mptcp/options.c
> index bb874c5d663a..1c5c99c06951 100644
> --- a/net/mptcp/options.c
> +++ b/net/mptcp/options.c
> @@ -1022,6 +1022,7 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
> 			mptcp_pm_add_addr_received(msk, &addr);
> 			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
> 		} else {
> +			mptcp_pm_add_addr_echoed(msk, &addr);
> 			mptcp_pm_del_add_timer(msk, &addr);
> 			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
> 		}
> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
> index 6fd4b2c1b076..a6d068d801d0 100644
> --- a/net/mptcp/pm.c
> +++ b/net/mptcp/pm.c
> @@ -197,6 +197,21 @@ void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
> 	spin_unlock_bh(&pm->lock);
> }
>
> +void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk, struct mptcp_addr_info *addr)
> +{
> +	struct mptcp_pm_data *pm = &msk->pm;
> +
> +	pr_debug("msk=%p", msk);
> +
> +	spin_lock_bh(&pm->lock);
> +
> +	__mptcp_flush_join_list(msk);

The msk lock needs to be held to call this and to iterate over 
msk->conn_list.

> +	if (!lookup_subflow_by_saddr(&msk->conn_list, addr))
> +		mptcp_pm_schedule_work(msk, MPTCP_PM_NEXT_ADDR);
> +
> +	spin_unlock_bh(&pm->lock);
> +}
> +
> void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk)
> {
> 	if (!mptcp_pm_should_add_signal(msk))
> diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
> index 8e8e35fa4002..d9eaee2037bd 100644
> --- a/net/mptcp/pm_netlink.c
> +++ b/net/mptcp/pm_netlink.c
> @@ -122,8 +122,8 @@ static void remote_address(const struct sock_common *skc,
> #endif
> }
>
> -static bool lookup_subflow_by_saddr(const struct list_head *list,
> -				    struct mptcp_addr_info *saddr)
> +bool lookup_subflow_by_saddr(const struct list_head *list,
> +			     struct mptcp_addr_info *saddr)
> {
> 	struct mptcp_subflow_context *subflow;
> 	struct mptcp_addr_info cur;
> @@ -608,6 +608,11 @@ static void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
> 	}
> }
>
> +static void mptcp_pm_nl_next_addr(struct mptcp_sock *msk)
> +{
> +	mptcp_pm_create_subflow_or_signal_addr(msk);
> +}
> +
> void mptcp_pm_nl_work(struct mptcp_sock *msk)
> {
> 	struct mptcp_pm_data *pm = &msk->pm;
> @@ -629,6 +634,10 @@ void mptcp_pm_nl_work(struct mptcp_sock *msk)
> 		pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED);
> 		mptcp_pm_nl_rm_addr_received(msk);
> 	}
> +	if (pm->status & BIT(MPTCP_PM_NEXT_ADDR)) {
> +		pm->status &= ~BIT(MPTCP_PM_NEXT_ADDR);
> +		mptcp_pm_nl_next_addr(msk);
> +	}
> 	if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
> 		pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
> 		mptcp_pm_nl_fully_established(msk);
> diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
> index de488c3a286e..7ad0dfef36bd 100644
> --- a/net/mptcp/protocol.h
> +++ b/net/mptcp/protocol.h
> @@ -176,6 +176,7 @@ enum mptcp_pm_status {
> 	MPTCP_PM_ADD_ADDR_RECEIVED,
> 	MPTCP_PM_ADD_ADDR_SEND_ACK,
> 	MPTCP_PM_RM_ADDR_RECEIVED,
> +	MPTCP_PM_NEXT_ADDR,

It looks like this flag and MPTCP_PM_ESTABLISHED end up doing exactly the 
same thing. Could just reuse the existing event and calls.

> 	MPTCP_PM_ESTABLISHED,
> 	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
> 	MPTCP_PM_SUBFLOW_ESTABLISHED,
> @@ -659,6 +660,9 @@ void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
> int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
> 				 struct mptcp_addr_info *addr,
> 				 u8 bkup);
> +void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk, struct mptcp_addr_info *addr);
> +bool lookup_subflow_by_saddr(const struct list_head *list,
> +			     struct mptcp_addr_info *saddr);
> void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
> bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
> struct mptcp_pm_add_entry *
> -- 
> 2.29.2

--
Mat Martineau
Intel