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