253 lines
5.6 KiB
C
253 lines
5.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Multipath TCP
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*
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* Copyright (c) 2019, Intel Corporation.
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*/
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#define pr_fmt(fmt) "MPTCP: " fmt
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#include <linux/kernel.h>
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#include <net/tcp.h>
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#include <net/mptcp.h>
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#include "protocol.h"
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/* path manager command handlers */
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int mptcp_pm_announce_addr(struct mptcp_sock *msk,
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const struct mptcp_addr_info *addr,
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bool echo)
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{
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pr_debug("msk=%p, local_id=%d", msk, addr->id);
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msk->pm.local = *addr;
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WRITE_ONCE(msk->pm.add_addr_echo, echo);
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WRITE_ONCE(msk->pm.add_addr_signal, true);
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return 0;
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}
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int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id)
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{
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pr_debug("msk=%p, local_id=%d", msk, local_id);
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msk->pm.rm_id = local_id;
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WRITE_ONCE(msk->pm.rm_addr_signal, true);
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return 0;
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}
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int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 local_id)
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{
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pr_debug("msk=%p, local_id=%d", msk, local_id);
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spin_lock_bh(&msk->pm.lock);
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mptcp_pm_nl_rm_subflow_received(msk, local_id);
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spin_unlock_bh(&msk->pm.lock);
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return 0;
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}
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/* path manager event handlers */
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void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side)
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{
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struct mptcp_pm_data *pm = &msk->pm;
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pr_debug("msk=%p, token=%u side=%d", msk, msk->token, server_side);
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WRITE_ONCE(pm->server_side, server_side);
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}
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bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
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{
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struct mptcp_pm_data *pm = &msk->pm;
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int ret = 0;
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pr_debug("msk=%p subflows=%d max=%d allow=%d", msk, pm->subflows,
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pm->subflows_max, READ_ONCE(pm->accept_subflow));
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/* try to avoid acquiring the lock below */
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if (!READ_ONCE(pm->accept_subflow))
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return false;
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spin_lock_bh(&pm->lock);
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if (READ_ONCE(pm->accept_subflow)) {
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ret = pm->subflows < pm->subflows_max;
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if (ret && ++pm->subflows == pm->subflows_max)
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WRITE_ONCE(pm->accept_subflow, false);
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}
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spin_unlock_bh(&pm->lock);
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return ret;
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}
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/* return true if the new status bit is currently cleared, that is, this event
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* can be server, eventually by an already scheduled work
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*/
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static bool mptcp_pm_schedule_work(struct mptcp_sock *msk,
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enum mptcp_pm_status new_status)
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{
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pr_debug("msk=%p status=%x new=%lx", msk, msk->pm.status,
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BIT(new_status));
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if (msk->pm.status & BIT(new_status))
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return false;
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msk->pm.status |= BIT(new_status);
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if (schedule_work(&msk->work))
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sock_hold((struct sock *)msk);
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return true;
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}
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void mptcp_pm_fully_established(struct mptcp_sock *msk)
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{
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struct mptcp_pm_data *pm = &msk->pm;
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pr_debug("msk=%p", msk);
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/* try to avoid acquiring the lock below */
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if (!READ_ONCE(pm->work_pending))
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return;
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spin_lock_bh(&pm->lock);
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if (READ_ONCE(pm->work_pending))
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mptcp_pm_schedule_work(msk, MPTCP_PM_ESTABLISHED);
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spin_unlock_bh(&pm->lock);
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}
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void mptcp_pm_connection_closed(struct mptcp_sock *msk)
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{
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pr_debug("msk=%p", msk);
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}
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void mptcp_pm_subflow_established(struct mptcp_sock *msk,
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struct mptcp_subflow_context *subflow)
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{
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struct mptcp_pm_data *pm = &msk->pm;
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pr_debug("msk=%p", msk);
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if (!READ_ONCE(pm->work_pending))
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return;
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spin_lock_bh(&pm->lock);
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if (READ_ONCE(pm->work_pending))
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mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED);
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spin_unlock_bh(&pm->lock);
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}
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void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
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{
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pr_debug("msk=%p", msk);
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}
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void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
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const struct mptcp_addr_info *addr)
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{
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struct mptcp_pm_data *pm = &msk->pm;
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pr_debug("msk=%p remote_id=%d accept=%d", msk, addr->id,
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READ_ONCE(pm->accept_addr));
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spin_lock_bh(&pm->lock);
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if (!READ_ONCE(pm->accept_addr))
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mptcp_pm_announce_addr(msk, addr, true);
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else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED))
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pm->remote = *addr;
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spin_unlock_bh(&pm->lock);
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}
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void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id)
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{
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struct mptcp_pm_data *pm = &msk->pm;
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pr_debug("msk=%p remote_id=%d", msk, rm_id);
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spin_lock_bh(&pm->lock);
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mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED);
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pm->rm_id = rm_id;
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spin_unlock_bh(&pm->lock);
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}
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/* path manager helpers */
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bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
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struct mptcp_addr_info *saddr, bool *echo)
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{
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int ret = false;
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spin_lock_bh(&msk->pm.lock);
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/* double check after the lock is acquired */
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if (!mptcp_pm_should_add_signal(msk))
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goto out_unlock;
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*echo = READ_ONCE(msk->pm.add_addr_echo);
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if (remaining < mptcp_add_addr_len(msk->pm.local.family, *echo))
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goto out_unlock;
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*saddr = msk->pm.local;
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WRITE_ONCE(msk->pm.add_addr_signal, false);
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ret = true;
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out_unlock:
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spin_unlock_bh(&msk->pm.lock);
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return ret;
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}
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bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
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u8 *rm_id)
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{
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int ret = false;
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spin_lock_bh(&msk->pm.lock);
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/* double check after the lock is acquired */
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if (!mptcp_pm_should_rm_signal(msk))
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goto out_unlock;
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if (remaining < TCPOLEN_MPTCP_RM_ADDR_BASE)
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goto out_unlock;
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*rm_id = msk->pm.rm_id;
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WRITE_ONCE(msk->pm.rm_addr_signal, false);
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ret = true;
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out_unlock:
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spin_unlock_bh(&msk->pm.lock);
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return ret;
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}
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int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
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{
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return mptcp_pm_nl_get_local_id(msk, skc);
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}
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void mptcp_pm_data_init(struct mptcp_sock *msk)
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{
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msk->pm.add_addr_signaled = 0;
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msk->pm.add_addr_accepted = 0;
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msk->pm.local_addr_used = 0;
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msk->pm.subflows = 0;
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msk->pm.rm_id = 0;
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WRITE_ONCE(msk->pm.work_pending, false);
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WRITE_ONCE(msk->pm.add_addr_signal, false);
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WRITE_ONCE(msk->pm.rm_addr_signal, false);
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WRITE_ONCE(msk->pm.accept_addr, false);
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WRITE_ONCE(msk->pm.accept_subflow, false);
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WRITE_ONCE(msk->pm.add_addr_echo, false);
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msk->pm.status = 0;
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spin_lock_init(&msk->pm.lock);
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INIT_LIST_HEAD(&msk->pm.anno_list);
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mptcp_pm_nl_data_init(msk);
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}
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void __init mptcp_pm_init(void)
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{
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mptcp_pm_nl_init();
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}
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