// SPDX-License-Identifier: GPL-2.0 /* Multipath TCP * * Copyright (c) 2019, Intel Corporation. */ #define pr_fmt(fmt) "MPTCP: " fmt #include #include #include "protocol.h" #include "mib.h" #define ADD_ADDR_RETRANS_MAX 3 struct mptcp_pm_add_entry { struct list_head list; struct mptcp_addr_info addr; u8 retrans_times; struct timer_list add_timer; struct mptcp_sock *sock; }; static DEFINE_SPINLOCK(mptcp_pm_list_lock); static LIST_HEAD(mptcp_pm_list); /* path manager helpers */ /* 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 } bool mptcp_addresses_equal(const struct mptcp_addr_info *a, const struct mptcp_addr_info *b, bool use_port) { bool addr_equals = false; if (a->family == b->family) { if (a->family == AF_INET) addr_equals = a->addr.s_addr == b->addr.s_addr; #if IS_ENABLED(CONFIG_MPTCP_IPV6) else addr_equals = ipv6_addr_equal(&a->addr6, &b->addr6); } else if (a->family == AF_INET) { if (ipv6_addr_v4mapped(&b->addr6)) addr_equals = a->addr.s_addr == b->addr6.s6_addr32[3]; } else if (b->family == AF_INET) { if (ipv6_addr_v4mapped(&a->addr6)) addr_equals = a->addr6.s6_addr32[3] == b->addr.s_addr; #endif } if (!addr_equals) return false; if (!use_port) return true; return a->port == b->port; } void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr) { addr->family = skc->skc_family; addr->port = htons(skc->skc_num); if (addr->family == AF_INET) addr->addr.s_addr = skc->skc_rcv_saddr; #if IS_ENABLED(CONFIG_MPTCP_IPV6) else if (addr->family == AF_INET6) addr->addr6 = skc->skc_v6_rcv_saddr; #endif } void mptcp_remote_address(const struct sock_common *skc, struct mptcp_addr_info *addr) { addr->family = skc->skc_family; addr->port = skc->skc_dport; if (addr->family == AF_INET) addr->addr.s_addr = skc->skc_daddr; #if IS_ENABLED(CONFIG_MPTCP_IPV6) else if (addr->family == AF_INET6) addr->addr6 = skc->skc_v6_daddr; #endif } static bool mptcp_pm_is_init_remote_addr(struct mptcp_sock *msk, const struct mptcp_addr_info *remote) { struct mptcp_addr_info mpc_remote; mptcp_remote_address((struct sock_common *)msk, &mpc_remote); return mptcp_addresses_equal(&mpc_remote, remote, remote->port); } bool mptcp_lookup_subflow_by_saddr(const struct list_head *list, const struct mptcp_addr_info *saddr) { struct mptcp_subflow_context *subflow; struct mptcp_addr_info cur; struct sock_common *skc; list_for_each_entry(subflow, list, node) { skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow); mptcp_local_address(skc, &cur); if (mptcp_addresses_equal(&cur, saddr, saddr->port)) return true; } return false; } static struct mptcp_pm_add_entry * mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk, const struct mptcp_addr_info *addr) { struct mptcp_pm_add_entry *entry; lockdep_assert_held(&msk->pm.lock); list_for_each_entry(entry, &msk->pm.anno_list, list) { if (mptcp_addresses_equal(&entry->addr, addr, true)) return entry; } return NULL; } bool mptcp_remove_anno_list_by_saddr(struct mptcp_sock *msk, const struct mptcp_addr_info *addr) { struct mptcp_pm_add_entry *entry; entry = mptcp_pm_del_add_timer(msk, addr, false); kfree(entry); return entry; } bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk) { struct mptcp_pm_add_entry *entry; struct mptcp_addr_info saddr; bool ret = false; mptcp_local_address((struct sock_common *)sk, &saddr); spin_lock_bh(&msk->pm.lock); list_for_each_entry(entry, &msk->pm.anno_list, list) { if (mptcp_addresses_equal(&entry->addr, &saddr, true)) { ret = true; goto out; } } out: spin_unlock_bh(&msk->pm.lock); return ret; } static void __mptcp_pm_send_ack(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow, bool prio, bool backup) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); bool slow; pr_debug("send ack for %s\n", prio ? "mp_prio" : (mptcp_pm_should_add_signal(msk) ? "add_addr" : "rm_addr")); slow = lock_sock_fast(ssk); if (prio) { subflow->send_mp_prio = 1; subflow->request_bkup = backup; } __mptcp_subflow_send_ack(ssk); unlock_sock_fast(ssk, slow); } void mptcp_pm_send_ack(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow, bool prio, bool backup) { spin_unlock_bh(&msk->pm.lock); __mptcp_pm_send_ack(msk, subflow, prio, backup); spin_lock_bh(&msk->pm.lock); } void mptcp_pm_addr_send_ack(struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow, *alt = NULL; msk_owned_by_me(msk); lockdep_assert_held(&msk->pm.lock); if (!mptcp_pm_should_add_signal(msk) && !mptcp_pm_should_rm_signal(msk)) return; mptcp_for_each_subflow(msk, subflow) { if (__mptcp_subflow_active(subflow)) { if (!subflow->stale) { mptcp_pm_send_ack(msk, subflow, false, false); return; } if (!alt) alt = subflow; } } if (alt) mptcp_pm_send_ack(msk, alt, false, false); } int mptcp_pm_mp_prio_send_ack(struct mptcp_sock *msk, struct mptcp_addr_info *addr, struct mptcp_addr_info *rem, u8 bkup) { struct mptcp_subflow_context *subflow; pr_debug("bkup=%d\n", bkup); mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); struct mptcp_addr_info local, remote; mptcp_local_address((struct sock_common *)ssk, &local); if (!mptcp_addresses_equal(&local, addr, addr->port)) continue; if (rem && rem->family != AF_UNSPEC) { mptcp_remote_address((struct sock_common *)ssk, &remote); if (!mptcp_addresses_equal(&remote, rem, rem->port)) continue; } __mptcp_pm_send_ack(msk, subflow, true, bkup); return 0; } return -EINVAL; } static void mptcp_pm_add_timer(struct timer_list *timer) { struct mptcp_pm_add_entry *entry = from_timer(entry, timer, add_timer); struct mptcp_sock *msk = entry->sock; struct sock *sk = (struct sock *)msk; pr_debug("msk=%p\n", msk); if (!msk) return; if (inet_sk_state_load(sk) == TCP_CLOSE) return; if (!entry->addr.id) return; if (mptcp_pm_should_add_signal_addr(msk)) { sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8); goto out; } spin_lock_bh(&msk->pm.lock); if (!mptcp_pm_should_add_signal_addr(msk)) { pr_debug("retransmit ADD_ADDR id=%d\n", entry->addr.id); mptcp_pm_announce_addr(msk, &entry->addr, false); mptcp_pm_add_addr_send_ack(msk); entry->retrans_times++; } if (entry->retrans_times < ADD_ADDR_RETRANS_MAX) sk_reset_timer(sk, timer, jiffies + mptcp_get_add_addr_timeout(sock_net(sk))); spin_unlock_bh(&msk->pm.lock); if (entry->retrans_times == ADD_ADDR_RETRANS_MAX) mptcp_pm_subflow_established(msk); out: __sock_put(sk); } struct mptcp_pm_add_entry * mptcp_pm_del_add_timer(struct mptcp_sock *msk, const struct mptcp_addr_info *addr, bool check_id) { struct mptcp_pm_add_entry *entry; struct sock *sk = (struct sock *)msk; struct timer_list *add_timer = NULL; spin_lock_bh(&msk->pm.lock); entry = mptcp_lookup_anno_list_by_saddr(msk, addr); if (entry && (!check_id || entry->addr.id == addr->id)) { entry->retrans_times = ADD_ADDR_RETRANS_MAX; add_timer = &entry->add_timer; } if (!check_id && entry) list_del(&entry->list); spin_unlock_bh(&msk->pm.lock); /* no lock, because sk_stop_timer_sync() is calling del_timer_sync() */ if (add_timer) sk_stop_timer_sync(sk, add_timer); return entry; } bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk, const struct mptcp_addr_info *addr) { struct mptcp_pm_add_entry *add_entry = NULL; struct sock *sk = (struct sock *)msk; struct net *net = sock_net(sk); lockdep_assert_held(&msk->pm.lock); add_entry = mptcp_lookup_anno_list_by_saddr(msk, addr); if (add_entry) { if (WARN_ON_ONCE(mptcp_pm_is_kernel(msk))) return false; sk_reset_timer(sk, &add_entry->add_timer, jiffies + mptcp_get_add_addr_timeout(net)); return true; } add_entry = kmalloc(sizeof(*add_entry), GFP_ATOMIC); if (!add_entry) return false; list_add(&add_entry->list, &msk->pm.anno_list); add_entry->addr = *addr; add_entry->sock = msk; add_entry->retrans_times = 0; timer_setup(&add_entry->add_timer, mptcp_pm_add_timer, 0); sk_reset_timer(sk, &add_entry->add_timer, jiffies + mptcp_get_add_addr_timeout(net)); return true; } static void mptcp_pm_free_anno_list(struct mptcp_sock *msk) { struct mptcp_pm_add_entry *entry, *tmp; struct sock *sk = (struct sock *)msk; LIST_HEAD(free_list); pr_debug("msk=%p\n", msk); spin_lock_bh(&msk->pm.lock); list_splice_init(&msk->pm.anno_list, &free_list); spin_unlock_bh(&msk->pm.lock); list_for_each_entry_safe(entry, tmp, &free_list, list) { sk_stop_timer_sync(sk, &entry->add_timer); kfree(entry); } } /* 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\n", msk, addr->id, echo); lockdep_assert_held(&msk->pm.lock); if (add_addr & (echo ? BIT(MPTCP_ADD_ADDR_ECHO) : BIT(MPTCP_ADD_ADDR_SIGNAL))) { MPTCP_INC_STATS(sock_net((struct sock *)msk), echo ? MPTCP_MIB_ECHOADDTXDROP : MPTCP_MIB_ADDADDRTXDROP); 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\n", msk, rm_list->nr); if (rm_addr) { MPTCP_ADD_STATS(sock_net((struct sock *)msk), MPTCP_MIB_RMADDRTXDROP, rm_list->nr); 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_addr_send_ack(msk); 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\n", msk, READ_ONCE(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\n", 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\n", 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\n", 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) && !(pm->status & BIT(MPTCP_PM_ALREADY_ESTABLISHED))) mptcp_pm_schedule_work(msk, MPTCP_PM_ESTABLISHED); if ((pm->status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)) == 0) announce = true; 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\n", msk); if (msk->token) mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); } void mptcp_pm_subflow_established(struct mptcp_sock *msk) { struct mptcp_pm_data *pm = &msk->pm; pr_debug("msk=%p\n", 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 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\n", 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); } /* id0 should not have a different address */ } else if ((addr->id == 0 && !mptcp_pm_is_init_remote_addr(msk, addr)) || (addr->id > 0 && !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\n", msk); if (!READ_ONCE(pm->work_pending)) return; 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); } static void mptcp_pm_rm_addr_or_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list, enum linux_mptcp_mib_field rm_type) { struct mptcp_subflow_context *subflow, *tmp; struct sock *sk = (struct sock *)msk; u8 i; pr_debug("%s rm_list_nr %d\n", rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow", rm_list->nr); msk_owned_by_me(msk); if (sk->sk_state == TCP_LISTEN) return; if (!rm_list->nr) return; if (list_empty(&msk->conn_list)) return; for (i = 0; i < rm_list->nr; i++) { u8 rm_id = rm_list->ids[i]; bool removed = false; mptcp_for_each_subflow_safe(msk, subflow, tmp) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); u8 remote_id = READ_ONCE(subflow->remote_id); int how = RCV_SHUTDOWN | SEND_SHUTDOWN; u8 id = subflow_get_local_id(subflow); if ((1 << inet_sk_state_load(ssk)) & (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING | TCPF_CLOSE)) continue; if (rm_type == MPTCP_MIB_RMADDR && remote_id != rm_id) continue; if (rm_type == MPTCP_MIB_RMSUBFLOW && id != rm_id) continue; pr_debug(" -> %s rm_list_ids[%d]=%u local_id=%u remote_id=%u mpc_id=%u\n", rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow", i, rm_id, id, remote_id, msk->mpc_endpoint_id); spin_unlock_bh(&msk->pm.lock); mptcp_subflow_shutdown(sk, ssk, how); removed |= subflow->request_join; /* the following takes care of updating the subflows counter */ mptcp_close_ssk(sk, ssk, subflow); spin_lock_bh(&msk->pm.lock); if (rm_type == MPTCP_MIB_RMSUBFLOW) __MPTCP_INC_STATS(sock_net(sk), rm_type); } if (rm_type == MPTCP_MIB_RMADDR) { __MPTCP_INC_STATS(sock_net(sk), rm_type); if (removed && mptcp_pm_is_kernel(msk)) mptcp_pm_nl_rm_addr(msk, rm_id); } } } static void mptcp_pm_rm_addr_recv(struct mptcp_sock *msk) { mptcp_pm_rm_addr_or_subflow(msk, &msk->pm.rm_list_rx, MPTCP_MIB_RMADDR); } void mptcp_pm_rm_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list) { mptcp_pm_rm_addr_or_subflow(msk, rm_list, MPTCP_MIB_RMSUBFLOW); } 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\n", 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_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\n", fail_seq); if (!READ_ONCE(msk->allow_infinite_fallback)) return; if (!subflow->fail_tout) { pr_debug("send MP_FAIL response and infinite map\n"); subflow->send_mp_fail = 1; subflow->send_infinite_map = 1; tcp_send_ack(sk); } else { pr_debug("MP_FAIL response received\n"); WRITE_ONCE(subflow->fail_tout, 0); } } 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) { struct mptcp_pm_addr_entry skc_local = { 0 }; struct mptcp_addr_info msk_local; if (WARN_ON_ONCE(!msk)) return -1; /* The 0 ID mapping is defined by the first subflow, copied into the msk * addr */ mptcp_local_address((struct sock_common *)msk, &msk_local); mptcp_local_address((struct sock_common *)skc, &skc_local.addr); if (mptcp_addresses_equal(&msk_local, &skc_local.addr, false)) return 0; skc_local.addr.id = 0; skc_local.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT; if (mptcp_pm_is_userspace(msk)) return mptcp_userspace_pm_get_local_id(msk, &skc_local); return mptcp_pm_nl_get_local_id(msk, &skc_local); } bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc) { struct mptcp_addr_info skc_local; mptcp_local_address((struct sock_common *)skc, &skc_local); if (mptcp_pm_is_userspace(msk)) return mptcp_userspace_pm_is_backup(msk, &skc_local); return mptcp_pm_nl_is_backup(msk, &skc_local); } static void mptcp_pm_subflows_chk_stale(const struct mptcp_sock *msk, struct sock *ssk) { struct mptcp_subflow_context *iter, *subflow = mptcp_subflow_ctx(ssk); struct sock *sk = (struct sock *)msk; unsigned int active_max_loss_cnt; struct net *net = sock_net(sk); unsigned int stale_loss_cnt; bool slow; stale_loss_cnt = mptcp_stale_loss_cnt(net); if (subflow->stale || !stale_loss_cnt || subflow->stale_count <= stale_loss_cnt) return; /* look for another available subflow not in loss state */ active_max_loss_cnt = max_t(int, stale_loss_cnt - 1, 1); mptcp_for_each_subflow(msk, iter) { if (iter != subflow && mptcp_subflow_active(iter) && iter->stale_count < active_max_loss_cnt) { /* we have some alternatives, try to mark this subflow as idle ...*/ slow = lock_sock_fast(ssk); if (!tcp_rtx_and_write_queues_empty(ssk)) { subflow->stale = 1; __mptcp_retransmit_pending_data(sk); MPTCP_INC_STATS(net, MPTCP_MIB_SUBFLOWSTALE); } unlock_sock_fast(ssk, slow); /* always try to push the pending data regardless of re-injections: * we can possibly use backup subflows now, and subflow selection * is cheap under the msk socket lock */ __mptcp_push_pending(sk, 0); return; } } } 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_subflows_chk_stale(msk, ssk); } else { subflow->stale_count = 0; mptcp_subflow_set_active(subflow); } } void mptcp_pm_worker(struct mptcp_sock *msk) { struct mptcp_pm_data *pm = &msk->pm; msk_owned_by_me(msk); if (!(pm->status & MPTCP_PM_WORK_MASK)) return; spin_lock_bh(&msk->pm.lock); pr_debug("msk=%p status=%x\n", msk, pm->status); if (pm->status & BIT(MPTCP_PM_ADD_ADDR_SEND_ACK)) { pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_SEND_ACK); mptcp_pm_addr_send_ack(msk); } if (pm->status & BIT(MPTCP_PM_RM_ADDR_RECEIVED)) { pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED); mptcp_pm_rm_addr_recv(msk); } __mptcp_pm_kernel_worker(msk); spin_unlock_bh(&msk->pm.lock); } void mptcp_pm_destroy(struct mptcp_sock *msk) { mptcp_pm_free_anno_list(msk); if (mptcp_pm_is_userspace(msk)) mptcp_userspace_pm_free_local_addr_list(msk); } 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; memset(&pm->reset, 0, sizeof(pm->reset)); 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); bitmap_fill(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_kernel_register(); mptcp_pm_userspace_register(); mptcp_pm_nl_init(); } /* Must be called with rcu read lock held */ struct mptcp_pm_ops *mptcp_pm_find(const char *name) { struct mptcp_pm_ops *pm_ops; list_for_each_entry_rcu(pm_ops, &mptcp_pm_list, list) { if (!strcmp(pm_ops->name, name)) return pm_ops; } return NULL; } int mptcp_pm_validate(struct mptcp_pm_ops *pm_ops) { return 0; } int mptcp_pm_register(struct mptcp_pm_ops *pm_ops) { int ret; ret = mptcp_pm_validate(pm_ops); if (ret) return ret; spin_lock(&mptcp_pm_list_lock); if (mptcp_pm_find(pm_ops->name)) { spin_unlock(&mptcp_pm_list_lock); return -EEXIST; } list_add_tail_rcu(&pm_ops->list, &mptcp_pm_list); spin_unlock(&mptcp_pm_list_lock); pr_debug("%s registered\n", pm_ops->name); return 0; } void mptcp_pm_unregister(struct mptcp_pm_ops *pm_ops) { /* skip unregistering the default path manager */ if (WARN_ON_ONCE(pm_ops == &mptcp_pm_kernel)) return; spin_lock(&mptcp_pm_list_lock); list_del_rcu(&pm_ops->list); spin_unlock(&mptcp_pm_list_lock); } /* Build string with list of available path manager values. * Similar to tcp_get_available_congestion_control() */ void mptcp_pm_get_available(char *buf, size_t maxlen) { struct mptcp_pm_ops *pm_ops; size_t offs = 0; rcu_read_lock(); list_for_each_entry_rcu(pm_ops, &mptcp_pm_list, list) { offs += snprintf(buf + offs, maxlen - offs, "%s%s", offs == 0 ? "" : " ", pm_ops->name); if (WARN_ON_ONCE(offs >= maxlen)) break; } rcu_read_unlock(); }