1 files changed, 473 insertions, 0 deletions

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
new file mode 100644
index 000000000000..45e2a48397b9
--- /dev/null
+++ b/net/mptcp/pm.c
@@ -0,0 +1,473 @@
+// 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);
+
+	pr_debug("fail_seq=%llu", fail_seq);
+
+	if (!READ_ONCE(msk->allow_infinite_fallback))
+		return;
+
+	if (!subflow->fail_tout) {
+		pr_debug("send MP_FAIL response and infinite map");
+
+		subflow->send_mp_fail = 1;
+		subflow->send_infinite_map = 1;
+		tcp_send_ack(sk);
+	} else {
+		pr_debug("MP_FAIL response received");
+		WRITE_ONCE(subflow->fail_tout, 0);
+	}
+}
+
+/* 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();
+}