499 lines
13 KiB
C
499 lines
13 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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#include "mib.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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u8 add_addr = READ_ONCE(msk->pm.addr_signal);
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pr_debug("msk=%p, local_id=%d, echo=%d", msk, addr->id, echo);
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lockdep_assert_held(&msk->pm.lock);
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if (add_addr &
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(echo ? BIT(MPTCP_ADD_ADDR_ECHO) : BIT(MPTCP_ADD_ADDR_SIGNAL))) {
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pr_warn("addr_signal error, add_addr=%d, echo=%d", add_addr, echo);
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return -EINVAL;
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}
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if (echo) {
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msk->pm.remote = *addr;
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add_addr |= BIT(MPTCP_ADD_ADDR_ECHO);
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} else {
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msk->pm.local = *addr;
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add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
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}
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WRITE_ONCE(msk->pm.addr_signal, add_addr);
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return 0;
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}
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int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list)
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{
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u8 rm_addr = READ_ONCE(msk->pm.addr_signal);
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pr_debug("msk=%p, rm_list_nr=%d", msk, rm_list->nr);
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if (rm_addr) {
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pr_warn("addr_signal error, rm_addr=%d", rm_addr);
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return -EINVAL;
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}
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msk->pm.rm_list_tx = *rm_list;
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rm_addr |= BIT(MPTCP_RM_ADDR_SIGNAL);
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WRITE_ONCE(msk->pm.addr_signal, rm_addr);
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mptcp_pm_nl_addr_send_ack(msk);
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return 0;
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}
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int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list)
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{
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pr_debug("msk=%p, rm_list_nr=%d", msk, rm_list->nr);
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spin_lock_bh(&msk->pm.lock);
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mptcp_pm_nl_rm_subflow_received(msk, rm_list);
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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, const struct sock *ssk, 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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mptcp_event(MPTCP_EVENT_CREATED, msk, ssk, GFP_ATOMIC);
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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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unsigned int subflows_max;
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int ret = 0;
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if (mptcp_pm_is_userspace(msk))
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return mptcp_userspace_pm_active(msk);
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subflows_max = mptcp_pm_get_subflows_max(msk);
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pr_debug("msk=%p subflows=%d max=%d allow=%d", msk, pm->subflows,
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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 < subflows_max;
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if (ret && ++pm->subflows == 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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mptcp_schedule_work((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, const struct sock *ssk)
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{
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struct mptcp_pm_data *pm = &msk->pm;
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bool announce = false;
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pr_debug("msk=%p", msk);
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spin_lock_bh(&pm->lock);
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/* mptcp_pm_fully_established() can be invoked by multiple
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* racing paths - accept() and check_fully_established()
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* be sure to serve this event only once.
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*/
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if (READ_ONCE(pm->work_pending) &&
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!(msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)))
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mptcp_pm_schedule_work(msk, MPTCP_PM_ESTABLISHED);
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if ((msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)) == 0)
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announce = true;
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msk->pm.status |= BIT(MPTCP_PM_ALREADY_ESTABLISHED);
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spin_unlock_bh(&pm->lock);
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if (announce)
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mptcp_event(MPTCP_EVENT_ESTABLISHED, msk, ssk, GFP_ATOMIC);
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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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{
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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_check_next(struct mptcp_sock *msk, const struct sock *ssk,
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const struct mptcp_subflow_context *subflow)
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{
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struct mptcp_pm_data *pm = &msk->pm;
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bool update_subflows;
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update_subflows = (subflow->request_join || subflow->mp_join) &&
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mptcp_pm_is_kernel(msk);
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if (!READ_ONCE(pm->work_pending) && !update_subflows)
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return;
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spin_lock_bh(&pm->lock);
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if (update_subflows)
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__mptcp_pm_close_subflow(msk);
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/* Even if this subflow is not really established, tell the PM to try
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* to pick the next ones, if possible.
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*/
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if (mptcp_pm_nl_check_work_pending(msk))
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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_add_addr_received(const struct sock *ssk,
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const struct mptcp_addr_info *addr)
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{
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
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struct mptcp_sock *msk = mptcp_sk(subflow->conn);
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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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mptcp_event_addr_announced(ssk, addr);
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spin_lock_bh(&pm->lock);
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if (mptcp_pm_is_userspace(msk)) {
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if (mptcp_userspace_pm_active(msk)) {
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mptcp_pm_announce_addr(msk, addr, true);
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mptcp_pm_add_addr_send_ack(msk);
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} else {
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__MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP);
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}
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} else if (!READ_ONCE(pm->accept_addr)) {
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mptcp_pm_announce_addr(msk, addr, true);
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mptcp_pm_add_addr_send_ack(msk);
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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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} else {
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__MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP);
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}
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spin_unlock_bh(&pm->lock);
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}
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void mptcp_pm_add_addr_echoed(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", msk);
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spin_lock_bh(&pm->lock);
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if (mptcp_lookup_anno_list_by_saddr(msk, addr) && 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_add_addr_send_ack(struct mptcp_sock *msk)
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{
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if (!mptcp_pm_should_add_signal(msk))
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return;
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mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_SEND_ACK);
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}
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void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
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const struct mptcp_rm_list *rm_list)
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{
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struct mptcp_pm_data *pm = &msk->pm;
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u8 i;
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pr_debug("msk=%p remote_ids_nr=%d", msk, rm_list->nr);
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for (i = 0; i < rm_list->nr; i++)
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mptcp_event_addr_removed(msk, rm_list->ids[i]);
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spin_lock_bh(&pm->lock);
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if (mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED))
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pm->rm_list_rx = *rm_list;
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else
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__MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_RMADDRDROP);
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spin_unlock_bh(&pm->lock);
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}
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void mptcp_pm_mp_prio_received(struct sock *ssk, u8 bkup)
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{
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
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struct sock *sk = subflow->conn;
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struct mptcp_sock *msk;
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pr_debug("subflow->backup=%d, bkup=%d\n", subflow->backup, bkup);
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msk = mptcp_sk(sk);
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if (subflow->backup != bkup) {
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subflow->backup = bkup;
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mptcp_data_lock(sk);
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if (!sock_owned_by_user(sk))
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msk->last_snd = NULL;
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else
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__set_bit(MPTCP_RESET_SCHEDULER, &msk->cb_flags);
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mptcp_data_unlock(sk);
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}
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mptcp_event(MPTCP_EVENT_SUB_PRIORITY, msk, ssk, GFP_ATOMIC);
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}
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void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq)
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{
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
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struct mptcp_sock *msk = mptcp_sk(subflow->conn);
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pr_debug("fail_seq=%llu", fail_seq);
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if (!READ_ONCE(msk->allow_infinite_fallback))
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return;
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if (!subflow->fail_tout) {
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pr_debug("send MP_FAIL response and infinite map");
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subflow->send_mp_fail = 1;
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subflow->send_infinite_map = 1;
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tcp_send_ack(sk);
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} else {
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pr_debug("MP_FAIL response received");
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WRITE_ONCE(subflow->fail_tout, 0);
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}
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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, const struct sk_buff *skb,
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unsigned int opt_size, unsigned int remaining,
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struct mptcp_addr_info *addr, bool *echo,
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bool *drop_other_suboptions)
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{
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int ret = false;
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u8 add_addr;
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u8 family;
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bool port;
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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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/* always drop every other options for pure ack ADD_ADDR; this is a
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* plain dup-ack from TCP perspective. The other MPTCP-relevant info,
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* if any, will be carried by the 'original' TCP ack
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*/
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if (skb && skb_is_tcp_pure_ack(skb)) {
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remaining += opt_size;
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*drop_other_suboptions = true;
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}
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*echo = mptcp_pm_should_add_signal_echo(msk);
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port = !!(*echo ? msk->pm.remote.port : msk->pm.local.port);
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family = *echo ? msk->pm.remote.family : msk->pm.local.family;
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if (remaining < mptcp_add_addr_len(family, *echo, port))
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goto out_unlock;
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if (*echo) {
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*addr = msk->pm.remote;
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add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_ECHO);
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} else {
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*addr = msk->pm.local;
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add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_SIGNAL);
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}
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WRITE_ONCE(msk->pm.addr_signal, add_addr);
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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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struct mptcp_rm_list *rm_list)
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{
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int ret = false, len;
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u8 rm_addr;
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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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rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL);
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len = mptcp_rm_addr_len(&msk->pm.rm_list_tx);
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if (len < 0) {
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WRITE_ONCE(msk->pm.addr_signal, rm_addr);
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goto out_unlock;
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}
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if (remaining < len)
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goto out_unlock;
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*rm_list = msk->pm.rm_list_tx;
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WRITE_ONCE(msk->pm.addr_signal, rm_addr);
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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_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
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{
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
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u32 rcv_tstamp = READ_ONCE(tcp_sk(ssk)->rcv_tstamp);
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/* keep track of rtx periods with no progress */
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if (!subflow->stale_count) {
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subflow->stale_rcv_tstamp = rcv_tstamp;
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subflow->stale_count++;
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} else if (subflow->stale_rcv_tstamp == rcv_tstamp) {
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if (subflow->stale_count < U8_MAX)
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subflow->stale_count++;
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mptcp_pm_nl_subflow_chk_stale(msk, ssk);
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} else {
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subflow->stale_count = 0;
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mptcp_subflow_set_active(subflow);
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}
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}
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/* if sk is ipv4 or ipv6_only allows only same-family local and remote addresses,
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* otherwise allow any matching local/remote pair
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*/
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bool mptcp_pm_addr_families_match(const struct sock *sk,
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const struct mptcp_addr_info *loc,
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const struct mptcp_addr_info *rem)
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{
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bool mptcp_is_v4 = sk->sk_family == AF_INET;
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#if IS_ENABLED(CONFIG_MPTCP_IPV6)
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bool loc_is_v4 = loc->family == AF_INET || ipv6_addr_v4mapped(&loc->addr6);
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bool rem_is_v4 = rem->family == AF_INET || ipv6_addr_v4mapped(&rem->addr6);
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if (mptcp_is_v4)
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return loc_is_v4 && rem_is_v4;
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if (ipv6_only_sock(sk))
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return !loc_is_v4 && !rem_is_v4;
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return loc_is_v4 == rem_is_v4;
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#else
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return mptcp_is_v4 && loc->family == AF_INET && rem->family == AF_INET;
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#endif
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}
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void mptcp_pm_data_reset(struct mptcp_sock *msk)
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{
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u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk));
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struct mptcp_pm_data *pm = &msk->pm;
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pm->add_addr_signaled = 0;
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pm->add_addr_accepted = 0;
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pm->local_addr_used = 0;
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pm->subflows = 0;
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pm->rm_list_tx.nr = 0;
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pm->rm_list_rx.nr = 0;
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WRITE_ONCE(pm->pm_type, pm_type);
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if (pm_type == MPTCP_PM_TYPE_KERNEL) {
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bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
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/* pm->work_pending must be only be set to 'true' when
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* pm->pm_type is set to MPTCP_PM_TYPE_KERNEL
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*/
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WRITE_ONCE(pm->work_pending,
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(!!mptcp_pm_get_local_addr_max(msk) &&
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subflows_allowed) ||
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!!mptcp_pm_get_add_addr_signal_max(msk));
|
|
WRITE_ONCE(pm->accept_addr,
|
|
!!mptcp_pm_get_add_addr_accept_max(msk) &&
|
|
subflows_allowed);
|
|
WRITE_ONCE(pm->accept_subflow, subflows_allowed);
|
|
} else {
|
|
WRITE_ONCE(pm->work_pending, 0);
|
|
WRITE_ONCE(pm->accept_addr, 0);
|
|
WRITE_ONCE(pm->accept_subflow, 0);
|
|
}
|
|
|
|
WRITE_ONCE(pm->addr_signal, 0);
|
|
WRITE_ONCE(pm->remote_deny_join_id0, false);
|
|
pm->status = 0;
|
|
bitmap_fill(msk->pm.id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
|
|
}
|
|
|
|
void mptcp_pm_data_init(struct mptcp_sock *msk)
|
|
{
|
|
spin_lock_init(&msk->pm.lock);
|
|
INIT_LIST_HEAD(&msk->pm.anno_list);
|
|
INIT_LIST_HEAD(&msk->pm.userspace_pm_local_addr_list);
|
|
mptcp_pm_data_reset(msk);
|
|
}
|
|
|
|
void __init mptcp_pm_init(void)
|
|
{
|
|
mptcp_pm_nl_init();
|
|
}
|