| // 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))) { |
| 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", 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_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, 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", 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 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_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) |
| { |
| struct mptcp_addr_info skc_local; |
| 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); |
| if (mptcp_addresses_equal(&msk_local, &skc_local, false)) |
| return 0; |
| |
| 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); |
| } |
| |
| int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id, |
| u8 *flags, int *ifindex) |
| { |
| *flags = 0; |
| *ifindex = 0; |
| |
| if (!id) |
| return 0; |
| |
| if (mptcp_pm_is_userspace(msk)) |
| return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk, id, flags, ifindex); |
| return mptcp_pm_nl_get_flags_and_ifindex_by_id(msk, id, flags, ifindex); |
| } |
| |
| int mptcp_pm_set_flags(struct net *net, struct nlattr *token, |
| struct mptcp_pm_addr_entry *loc, |
| struct mptcp_pm_addr_entry *rem, u8 bkup) |
| { |
| if (token) |
| return mptcp_userspace_pm_set_flags(net, token, loc, rem, bkup); |
| return mptcp_pm_nl_set_flags(net, loc, bkup); |
| } |
| |
| 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(); |
| } |