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-rw-r--r--net/mptcp/pm.c513
1 files changed, 513 insertions, 0 deletions
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
new file mode 100644
index 000000000..10c288a0c
--- /dev/null
+++ b/net/mptcp/pm.c
@@ -0,0 +1,513 @@
+// 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)) {
+ if (mptcp_userspace_pm_active(msk)) {
+ spin_lock_bh(&pm->lock);
+ pm->subflows++;
+ spin_unlock_bh(&pm->lock);
+ return true;
+ }
+ return false;
+ }
+
+ 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;
+ if (mptcp_pm_is_userspace(msk)) {
+ if (update_subflows) {
+ spin_lock_bh(&pm->lock);
+ pm->subflows--;
+ spin_unlock_bh(&pm->lock);
+ }
+ return;
+ }
+
+ 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);
+ }
+}
+
+/* if sk is ipv4 or ipv6_only allows only same-family local and remote addresses,
+ * otherwise allow any matching local/remote pair
+ */
+bool mptcp_pm_addr_families_match(const struct sock *sk,
+ const struct mptcp_addr_info *loc,
+ const struct mptcp_addr_info *rem)
+{
+ bool mptcp_is_v4 = sk->sk_family == AF_INET;
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ bool loc_is_v4 = loc->family == AF_INET || ipv6_addr_v4mapped(&loc->addr6);
+ bool rem_is_v4 = rem->family == AF_INET || ipv6_addr_v4mapped(&rem->addr6);
+
+ if (mptcp_is_v4)
+ return loc_is_v4 && rem_is_v4;
+
+ if (ipv6_only_sock(sk))
+ return !loc_is_v4 && !rem_is_v4;
+
+ return loc_is_v4 == rem_is_v4;
+#else
+ return mptcp_is_v4 && loc->family == AF_INET && rem->family == AF_INET;
+#endif
+}
+
+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();
+}
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