blob: 8ba51120f35b38ae7970f048b2094255de5fae9a [file] [log] [blame]
// 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"
#include "mib.h"
/* path manager command handlers */
int mptcp_pm_announce_addr(struct mptcp_sock *msk,
const struct mptcp_addr_info *addr,
bool echo)
{
u8 add_addr = READ_ONCE(msk->pm.addr_signal);
pr_debug("msk=%p, local_id=%d, echo=%d", msk, addr->id, echo);
lockdep_assert_held(&msk->pm.lock);
if (add_addr &
(echo ? BIT(MPTCP_ADD_ADDR_ECHO) : BIT(MPTCP_ADD_ADDR_SIGNAL))) {
pr_warn("addr_signal error, add_addr=%d, echo=%d", add_addr, echo);
return -EINVAL;
}
if (echo) {
msk->pm.remote = *addr;
add_addr |= BIT(MPTCP_ADD_ADDR_ECHO);
} else {
msk->pm.local = *addr;
add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
}
WRITE_ONCE(msk->pm.addr_signal, add_addr);
return 0;
}
int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list)
{
u8 rm_addr = READ_ONCE(msk->pm.addr_signal);
pr_debug("msk=%p, rm_list_nr=%d", msk, rm_list->nr);
if (rm_addr) {
pr_warn("addr_signal error, rm_addr=%d", rm_addr);
return -EINVAL;
}
msk->pm.rm_list_tx = *rm_list;
rm_addr |= BIT(MPTCP_RM_ADDR_SIGNAL);
WRITE_ONCE(msk->pm.addr_signal, rm_addr);
mptcp_pm_nl_addr_send_ack(msk);
return 0;
}
int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list)
{
pr_debug("msk=%p, rm_list_nr=%d", msk, rm_list->nr);
spin_lock_bh(&msk->pm.lock);
mptcp_pm_nl_rm_subflow_received(msk, rm_list);
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;
if (mptcp_pm_is_userspace(msk))
return mptcp_userspace_pm_active(msk);
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_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_check_next(struct mptcp_sock *msk, const struct sock *ssk,
const struct mptcp_subflow_context *subflow)
{
struct mptcp_pm_data *pm = &msk->pm;
bool update_subflows;
update_subflows = (subflow->request_join || subflow->mp_join) &&
mptcp_pm_is_kernel(msk);
if (!READ_ONCE(pm->work_pending) && !update_subflows)
return;
spin_lock_bh(&pm->lock);
if (update_subflows)
__mptcp_pm_close_subflow(msk);
/* Even if this subflow is not really established, tell the PM to try
* to pick the next ones, if possible.
*/
if (mptcp_pm_nl_check_work_pending(msk))
mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED);
spin_unlock_bh(&pm->lock);
}
void mptcp_pm_add_addr_received(const struct sock *ssk,
const struct mptcp_addr_info *addr)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
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(ssk, addr);
spin_lock_bh(&pm->lock);
if (mptcp_pm_is_userspace(msk)) {
if (mptcp_userspace_pm_active(msk)) {
mptcp_pm_announce_addr(msk, addr, true);
mptcp_pm_add_addr_send_ack(msk);
} else {
__MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP);
}
} else if (!READ_ONCE(pm->accept_addr)) {
mptcp_pm_announce_addr(msk, addr, true);
mptcp_pm_add_addr_send_ack(msk);
} else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) {
pm->remote = *addr;
} else {
__MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP);
}
spin_unlock_bh(&pm->lock);
}
void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
const struct mptcp_addr_info *addr)
{
struct mptcp_pm_data *pm = &msk->pm;
pr_debug("msk=%p", msk);
spin_lock_bh(&pm->lock);
if (mptcp_lookup_anno_list_by_saddr(msk, addr) && READ_ONCE(pm->work_pending))
mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED);
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,
const struct mptcp_rm_list *rm_list)
{
struct mptcp_pm_data *pm = &msk->pm;
u8 i;
pr_debug("msk=%p remote_ids_nr=%d", msk, rm_list->nr);
for (i = 0; i < rm_list->nr; i++)
mptcp_event_addr_removed(msk, rm_list->ids[i]);
spin_lock_bh(&pm->lock);
if (mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED))
pm->rm_list_rx = *rm_list;
else
__MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_RMADDRDROP);
spin_unlock_bh(&pm->lock);
}
void mptcp_pm_mp_prio_received(struct sock *ssk, u8 bkup)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct sock *sk = subflow->conn;
struct mptcp_sock *msk;
pr_debug("subflow->backup=%d, bkup=%d\n", subflow->backup, bkup);
msk = mptcp_sk(sk);
if (subflow->backup != bkup) {
subflow->backup = bkup;
mptcp_data_lock(sk);
if (!sock_owned_by_user(sk))
msk->last_snd = NULL;
else
__set_bit(MPTCP_RESET_SCHEDULER, &msk->cb_flags);
mptcp_data_unlock(sk);
}
mptcp_event(MPTCP_EVENT_SUB_PRIORITY, msk, ssk, GFP_ATOMIC);
}
void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
struct sock *s = (struct sock *)msk;
pr_debug("fail_seq=%llu", fail_seq);
if (!READ_ONCE(msk->allow_infinite_fallback))
return;
if (!READ_ONCE(subflow->mp_fail_response_expect)) {
pr_debug("send MP_FAIL response and infinite map");
subflow->send_mp_fail = 1;
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFAILTX);
subflow->send_infinite_map = 1;
} else if (s && inet_sk_state_load(s) != TCP_CLOSE) {
pr_debug("MP_FAIL response received");
mptcp_data_lock(s);
if (inet_sk_state_load(s) != TCP_CLOSE)
sk_stop_timer(s, &s->sk_timer);
mptcp_data_unlock(s);
}
}
/* path manager helpers */
bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
unsigned int opt_size, unsigned int remaining,
struct mptcp_addr_info *addr, bool *echo,
bool *drop_other_suboptions)
{
int ret = false;
u8 add_addr;
u8 family;
bool port;
spin_lock_bh(&msk->pm.lock);
/* double check after the lock is acquired */
if (!mptcp_pm_should_add_signal(msk))
goto out_unlock;
/* always drop every other options for pure ack ADD_ADDR; this is a
* plain dup-ack from TCP perspective. The other MPTCP-relevant info,
* if any, will be carried by the 'original' TCP ack
*/
if (skb && skb_is_tcp_pure_ack(skb)) {
remaining += opt_size;
*drop_other_suboptions = true;
}
*echo = mptcp_pm_should_add_signal_echo(msk);
port = !!(*echo ? msk->pm.remote.port : msk->pm.local.port);
family = *echo ? msk->pm.remote.family : msk->pm.local.family;
if (remaining < mptcp_add_addr_len(family, *echo, port))
goto out_unlock;
if (*echo) {
*addr = msk->pm.remote;
add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_ECHO);
} else {
*addr = msk->pm.local;
add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_SIGNAL);
}
WRITE_ONCE(msk->pm.addr_signal, add_addr);
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,
struct mptcp_rm_list *rm_list)
{
int ret = false, len;
u8 rm_addr;
spin_lock_bh(&msk->pm.lock);
/* double check after the lock is acquired */
if (!mptcp_pm_should_rm_signal(msk))
goto out_unlock;
rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL);
len = mptcp_rm_addr_len(&msk->pm.rm_list_tx);
if (len < 0) {
WRITE_ONCE(msk->pm.addr_signal, rm_addr);
goto out_unlock;
}
if (remaining < len)
goto out_unlock;
*rm_list = msk->pm.rm_list_tx;
WRITE_ONCE(msk->pm.addr_signal, rm_addr);
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_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
u32 rcv_tstamp = READ_ONCE(tcp_sk(ssk)->rcv_tstamp);
/* keep track of rtx periods with no progress */
if (!subflow->stale_count) {
subflow->stale_rcv_tstamp = rcv_tstamp;
subflow->stale_count++;
} else if (subflow->stale_rcv_tstamp == rcv_tstamp) {
if (subflow->stale_count < U8_MAX)
subflow->stale_count++;
mptcp_pm_nl_subflow_chk_stale(msk, ssk);
} else {
subflow->stale_count = 0;
mptcp_subflow_set_active(subflow);
}
}
void mptcp_pm_data_reset(struct mptcp_sock *msk)
{
u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk));
struct mptcp_pm_data *pm = &msk->pm;
pm->add_addr_signaled = 0;
pm->add_addr_accepted = 0;
pm->local_addr_used = 0;
pm->subflows = 0;
pm->rm_list_tx.nr = 0;
pm->rm_list_rx.nr = 0;
WRITE_ONCE(pm->pm_type, pm_type);
if (pm_type == MPTCP_PM_TYPE_KERNEL) {
bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
/* pm->work_pending must be only be set to 'true' when
* pm->pm_type is set to MPTCP_PM_TYPE_KERNEL
*/
WRITE_ONCE(pm->work_pending,
(!!mptcp_pm_get_local_addr_max(msk) &&
subflows_allowed) ||
!!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();
}