// SPDX-License-Identifier: GPL-2.0 /* Multipath TCP * * Copyright (c) 2019, Intel Corporation. */ #define pr_fmt(fmt) "MPTCP: " fmt #include #include #include #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) { 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_ATOMIC); } 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(); }