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// 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, bool port)
{
u8 add_addr = READ_ONCE(msk->pm.addr_signal);
pr_debug("msk=%p, local_id=%d", msk, addr->id);
lockdep_assert_held(&msk->pm.lock);
if (add_addr) {
pr_warn("addr_signal error, add_addr=%d", add_addr);
return -EINVAL;
}
msk->pm.local = *addr;
add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
if (echo)
add_addr |= BIT(MPTCP_ADD_ADDR_ECHO);
if (addr->family == AF_INET6)
add_addr |= BIT(MPTCP_ADD_ADDR_IPV6);
if (port)
add_addr |= BIT(MPTCP_ADD_ADDR_PORT);
WRITE_ONCE(msk->pm.addr_signal, add_addr);
return 0;
}
int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id)
{
u8 rm_addr = READ_ONCE(msk->pm.addr_signal);
pr_debug("msk=%p, local_id=%d", msk, local_id);
if (rm_addr) {
pr_warn("addr_signal error, rm_addr=%d", rm_addr);
return -EINVAL;
}
msk->pm.rm_id = local_id;
rm_addr |= BIT(MPTCP_RM_ADDR_SIGNAL);
WRITE_ONCE(msk->pm.addr_signal, rm_addr);
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, const struct sock *ssk, 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);
mptcp_event(MPTCP_EVENT_CREATED, msk, ssk, GFP_ATOMIC);
}
bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
{
struct mptcp_pm_data *pm = &msk->pm;
unsigned int subflows_max;
int ret = 0;
subflows_max = mptcp_pm_get_subflows_max(msk);
pr_debug("msk=%p subflows=%d max=%d allow=%d", msk, pm->subflows,
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 < subflows_max;
if (ret && ++pm->subflows == 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);
mptcp_schedule_work((struct sock *)msk);
return true;
}
void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk, gfp_t gfp)
{
struct mptcp_pm_data *pm = &msk->pm;
bool announce = false;
pr_debug("msk=%p", msk);
spin_lock_bh(&pm->lock);
/* mptcp_pm_fully_established() can be invoked by multiple
* racing paths - accept() and check_fully_established()
* be sure to serve this event only once.
*/
if (READ_ONCE(pm->work_pending) &&
!(msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)))
mptcp_pm_schedule_work(msk, MPTCP_PM_ESTABLISHED);
if ((msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)) == 0)
announce = true;
msk->pm.status |= BIT(MPTCP_PM_ALREADY_ESTABLISHED);
spin_unlock_bh(&pm->lock);
if (announce)
mptcp_event(MPTCP_EVENT_ESTABLISHED, msk, ssk, gfp);
}
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));
mptcp_event_addr_announced(msk, addr);
spin_lock_bh(&pm->lock);
if (!READ_ONCE(pm->accept_addr)) {
mptcp_pm_announce_addr(msk, addr, true, addr->port);
mptcp_pm_add_addr_send_ack(msk);
} else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) {
pm->remote = *addr;
}
spin_unlock_bh(&pm->lock);
}
void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk)
{
if (!mptcp_pm_should_add_signal(msk))
return;
mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_SEND_ACK);
}
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);
mptcp_event_addr_removed(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);
}
void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
pr_debug("subflow->backup=%d, bkup=%d\n", subflow->backup, bkup);
subflow->backup = bkup;
mptcp_event(MPTCP_EVENT_SUB_PRIORITY, mptcp_sk(subflow->conn), sk, GFP_ATOMIC);
}
/* path manager helpers */
bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
struct mptcp_addr_info *saddr, bool *echo, bool *port)
{
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 = mptcp_pm_should_add_signal_echo(msk);
*port = mptcp_pm_should_add_signal_port(msk);
if (remaining < mptcp_add_addr_len(msk->pm.local.family, *echo, *port))
goto out_unlock;
*saddr = msk->pm.local;
WRITE_ONCE(msk->pm.addr_signal, 0);
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.addr_signal, 0);
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.addr_signal, 0);
WRITE_ONCE(msk->pm.accept_addr, false);
WRITE_ONCE(msk->pm.accept_subflow, 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();
}
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