| // SPDX-License-Identifier: GPL-2.0 |
| /* Multipath TCP |
| * |
| * Copyright (c) 2017 - 2019, Intel Corporation. |
| */ |
| |
| #define pr_fmt(fmt) "MPTCP: " fmt |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/netdevice.h> |
| #include <linux/sched/signal.h> |
| #include <linux/atomic.h> |
| #include <net/sock.h> |
| #include <net/inet_common.h> |
| #include <net/inet_hashtables.h> |
| #include <net/protocol.h> |
| #include <net/tcp.h> |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| #include <net/transp_v6.h> |
| #endif |
| #include <net/mptcp.h> |
| #include "protocol.h" |
| #include "mib.h" |
| |
| #define MPTCP_SAME_STATE TCP_MAX_STATES |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| struct mptcp6_sock { |
| struct mptcp_sock msk; |
| struct ipv6_pinfo np; |
| }; |
| #endif |
| |
| struct mptcp_skb_cb { |
| u32 offset; |
| }; |
| |
| #define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0])) |
| |
| static struct percpu_counter mptcp_sockets_allocated; |
| |
| /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not |
| * completed yet or has failed, return the subflow socket. |
| * Otherwise return NULL. |
| */ |
| static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk) |
| { |
| if (!msk->subflow || READ_ONCE(msk->can_ack)) |
| return NULL; |
| |
| return msk->subflow; |
| } |
| |
| static bool __mptcp_needs_tcp_fallback(const struct mptcp_sock *msk) |
| { |
| return msk->first && !sk_is_mptcp(msk->first); |
| } |
| |
| static struct socket *mptcp_is_tcpsk(struct sock *sk) |
| { |
| struct socket *sock = sk->sk_socket; |
| |
| if (sock->sk != sk) |
| return NULL; |
| |
| if (unlikely(sk->sk_prot == &tcp_prot)) { |
| /* we are being invoked after mptcp_accept() has |
| * accepted a non-mp-capable flow: sk is a tcp_sk, |
| * not an mptcp one. |
| * |
| * Hand the socket over to tcp so all further socket ops |
| * bypass mptcp. |
| */ |
| sock->ops = &inet_stream_ops; |
| return sock; |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| } else if (unlikely(sk->sk_prot == &tcpv6_prot)) { |
| sock->ops = &inet6_stream_ops; |
| return sock; |
| #endif |
| } |
| |
| return NULL; |
| } |
| |
| static struct socket *__mptcp_tcp_fallback(struct mptcp_sock *msk) |
| { |
| struct socket *sock; |
| |
| sock_owned_by_me((const struct sock *)msk); |
| |
| sock = mptcp_is_tcpsk((struct sock *)msk); |
| if (unlikely(sock)) |
| return sock; |
| |
| if (likely(!__mptcp_needs_tcp_fallback(msk))) |
| return NULL; |
| |
| if (msk->subflow) { |
| release_sock((struct sock *)msk); |
| return msk->subflow; |
| } |
| |
| return NULL; |
| } |
| |
| static bool __mptcp_can_create_subflow(const struct mptcp_sock *msk) |
| { |
| return !msk->first; |
| } |
| |
| static struct socket *__mptcp_socket_create(struct mptcp_sock *msk, int state) |
| { |
| struct mptcp_subflow_context *subflow; |
| struct sock *sk = (struct sock *)msk; |
| struct socket *ssock; |
| int err; |
| |
| ssock = __mptcp_tcp_fallback(msk); |
| if (unlikely(ssock)) |
| return ssock; |
| |
| ssock = __mptcp_nmpc_socket(msk); |
| if (ssock) |
| goto set_state; |
| |
| if (!__mptcp_can_create_subflow(msk)) |
| return ERR_PTR(-EINVAL); |
| |
| err = mptcp_subflow_create_socket(sk, &ssock); |
| if (err) |
| return ERR_PTR(err); |
| |
| msk->first = ssock->sk; |
| msk->subflow = ssock; |
| subflow = mptcp_subflow_ctx(ssock->sk); |
| list_add(&subflow->node, &msk->conn_list); |
| subflow->request_mptcp = 1; |
| |
| set_state: |
| if (state != MPTCP_SAME_STATE) |
| inet_sk_state_store(sk, state); |
| return ssock; |
| } |
| |
| static void __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, |
| struct sk_buff *skb, |
| unsigned int offset, size_t copy_len) |
| { |
| struct sock *sk = (struct sock *)msk; |
| |
| __skb_unlink(skb, &ssk->sk_receive_queue); |
| skb_set_owner_r(skb, sk); |
| __skb_queue_tail(&sk->sk_receive_queue, skb); |
| |
| msk->ack_seq += copy_len; |
| MPTCP_SKB_CB(skb)->offset = offset; |
| } |
| |
| /* both sockets must be locked */ |
| static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk, |
| struct sock *ssk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| u64 dsn = mptcp_subflow_get_mapped_dsn(subflow); |
| |
| /* revalidate data sequence number. |
| * |
| * mptcp_subflow_data_available() is usually called |
| * without msk lock. Its unlikely (but possible) |
| * that msk->ack_seq has been advanced since the last |
| * call found in-sequence data. |
| */ |
| if (likely(dsn == msk->ack_seq)) |
| return true; |
| |
| subflow->data_avail = 0; |
| return mptcp_subflow_data_available(ssk); |
| } |
| |
| static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, |
| struct sock *ssk, |
| unsigned int *bytes) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| struct sock *sk = (struct sock *)msk; |
| unsigned int moved = 0; |
| bool more_data_avail; |
| struct tcp_sock *tp; |
| bool done = false; |
| |
| if (!mptcp_subflow_dsn_valid(msk, ssk)) { |
| *bytes = 0; |
| return false; |
| } |
| |
| if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { |
| int rcvbuf = max(ssk->sk_rcvbuf, sk->sk_rcvbuf); |
| |
| if (rcvbuf > sk->sk_rcvbuf) |
| sk->sk_rcvbuf = rcvbuf; |
| } |
| |
| tp = tcp_sk(ssk); |
| do { |
| u32 map_remaining, offset; |
| u32 seq = tp->copied_seq; |
| struct sk_buff *skb; |
| bool fin; |
| |
| /* try to move as much data as available */ |
| map_remaining = subflow->map_data_len - |
| mptcp_subflow_get_map_offset(subflow); |
| |
| skb = skb_peek(&ssk->sk_receive_queue); |
| if (!skb) |
| break; |
| |
| offset = seq - TCP_SKB_CB(skb)->seq; |
| fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; |
| if (fin) { |
| done = true; |
| seq++; |
| } |
| |
| if (offset < skb->len) { |
| size_t len = skb->len - offset; |
| |
| if (tp->urg_data) |
| done = true; |
| |
| __mptcp_move_skb(msk, ssk, skb, offset, len); |
| seq += len; |
| moved += len; |
| |
| if (WARN_ON_ONCE(map_remaining < len)) |
| break; |
| } else { |
| WARN_ON_ONCE(!fin); |
| sk_eat_skb(ssk, skb); |
| done = true; |
| } |
| |
| WRITE_ONCE(tp->copied_seq, seq); |
| more_data_avail = mptcp_subflow_data_available(ssk); |
| |
| if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf)) { |
| done = true; |
| break; |
| } |
| } while (more_data_avail); |
| |
| *bytes = moved; |
| |
| return done; |
| } |
| |
| /* In most cases we will be able to lock the mptcp socket. If its already |
| * owned, we need to defer to the work queue to avoid ABBA deadlock. |
| */ |
| static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk) |
| { |
| struct sock *sk = (struct sock *)msk; |
| unsigned int moved = 0; |
| |
| if (READ_ONCE(sk->sk_lock.owned)) |
| return false; |
| |
| if (unlikely(!spin_trylock_bh(&sk->sk_lock.slock))) |
| return false; |
| |
| /* must re-check after taking the lock */ |
| if (!READ_ONCE(sk->sk_lock.owned)) |
| __mptcp_move_skbs_from_subflow(msk, ssk, &moved); |
| |
| spin_unlock_bh(&sk->sk_lock.slock); |
| |
| return moved > 0; |
| } |
| |
| void mptcp_data_ready(struct sock *sk, struct sock *ssk) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| set_bit(MPTCP_DATA_READY, &msk->flags); |
| |
| if (atomic_read(&sk->sk_rmem_alloc) < READ_ONCE(sk->sk_rcvbuf) && |
| move_skbs_to_msk(msk, ssk)) |
| goto wake; |
| |
| /* don't schedule if mptcp sk is (still) over limit */ |
| if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf)) |
| goto wake; |
| |
| /* mptcp socket is owned, release_cb should retry */ |
| if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED, |
| &sk->sk_tsq_flags)) { |
| sock_hold(sk); |
| |
| /* need to try again, its possible release_cb() has already |
| * been called after the test_and_set_bit() above. |
| */ |
| move_skbs_to_msk(msk, ssk); |
| } |
| wake: |
| sk->sk_data_ready(sk); |
| } |
| |
| static void __mptcp_flush_join_list(struct mptcp_sock *msk) |
| { |
| if (likely(list_empty(&msk->join_list))) |
| return; |
| |
| spin_lock_bh(&msk->join_list_lock); |
| list_splice_tail_init(&msk->join_list, &msk->conn_list); |
| spin_unlock_bh(&msk->join_list_lock); |
| } |
| |
| static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk) |
| { |
| long tout = ssk && inet_csk(ssk)->icsk_pending ? |
| inet_csk(ssk)->icsk_timeout - jiffies : 0; |
| |
| if (tout <= 0) |
| tout = mptcp_sk(sk)->timer_ival; |
| mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; |
| } |
| |
| static bool mptcp_timer_pending(struct sock *sk) |
| { |
| return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); |
| } |
| |
| static void mptcp_reset_timer(struct sock *sk) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| unsigned long tout; |
| |
| /* should never be called with mptcp level timer cleared */ |
| tout = READ_ONCE(mptcp_sk(sk)->timer_ival); |
| if (WARN_ON_ONCE(!tout)) |
| tout = TCP_RTO_MIN; |
| sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout); |
| } |
| |
| void mptcp_data_acked(struct sock *sk) |
| { |
| mptcp_reset_timer(sk); |
| |
| if (!sk_stream_is_writeable(sk) && |
| schedule_work(&mptcp_sk(sk)->work)) |
| sock_hold(sk); |
| } |
| |
| void mptcp_subflow_eof(struct sock *sk) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| if (!test_and_set_bit(MPTCP_WORK_EOF, &msk->flags) && |
| schedule_work(&msk->work)) |
| sock_hold(sk); |
| } |
| |
| static void mptcp_stop_timer(struct sock *sk) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| |
| sk_stop_timer(sk, &icsk->icsk_retransmit_timer); |
| mptcp_sk(sk)->timer_ival = 0; |
| } |
| |
| static bool mptcp_ext_cache_refill(struct mptcp_sock *msk) |
| { |
| if (!msk->cached_ext) |
| msk->cached_ext = __skb_ext_alloc(); |
| |
| return !!msk->cached_ext; |
| } |
| |
| static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk) |
| { |
| struct mptcp_subflow_context *subflow; |
| struct sock *sk = (struct sock *)msk; |
| |
| sock_owned_by_me(sk); |
| |
| mptcp_for_each_subflow(msk, subflow) { |
| if (subflow->data_avail) |
| return mptcp_subflow_tcp_sock(subflow); |
| } |
| |
| return NULL; |
| } |
| |
| static bool mptcp_skb_can_collapse_to(u64 write_seq, |
| const struct sk_buff *skb, |
| const struct mptcp_ext *mpext) |
| { |
| if (!tcp_skb_can_collapse_to(skb)) |
| return false; |
| |
| /* can collapse only if MPTCP level sequence is in order */ |
| return mpext && mpext->data_seq + mpext->data_len == write_seq; |
| } |
| |
| static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, |
| const struct page_frag *pfrag, |
| const struct mptcp_data_frag *df) |
| { |
| return df && pfrag->page == df->page && |
| df->data_seq + df->data_len == msk->write_seq; |
| } |
| |
| static void dfrag_uncharge(struct sock *sk, int len) |
| { |
| sk_mem_uncharge(sk, len); |
| sk_wmem_queued_add(sk, -len); |
| } |
| |
| static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag) |
| { |
| int len = dfrag->data_len + dfrag->overhead; |
| |
| list_del(&dfrag->list); |
| dfrag_uncharge(sk, len); |
| put_page(dfrag->page); |
| } |
| |
| static void mptcp_clean_una(struct sock *sk) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct mptcp_data_frag *dtmp, *dfrag; |
| u64 snd_una = atomic64_read(&msk->snd_una); |
| bool cleaned = false; |
| |
| list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { |
| if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) |
| break; |
| |
| dfrag_clear(sk, dfrag); |
| cleaned = true; |
| } |
| |
| dfrag = mptcp_rtx_head(sk); |
| if (dfrag && after64(snd_una, dfrag->data_seq)) { |
| u64 delta = dfrag->data_seq + dfrag->data_len - snd_una; |
| |
| dfrag->data_seq += delta; |
| dfrag->data_len -= delta; |
| |
| dfrag_uncharge(sk, delta); |
| cleaned = true; |
| } |
| |
| if (cleaned) { |
| sk_mem_reclaim_partial(sk); |
| |
| /* Only wake up writers if a subflow is ready */ |
| if (test_bit(MPTCP_SEND_SPACE, &msk->flags)) |
| sk_stream_write_space(sk); |
| } |
| } |
| |
| /* ensure we get enough memory for the frag hdr, beyond some minimal amount of |
| * data |
| */ |
| static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag) |
| { |
| if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag), |
| pfrag, sk->sk_allocation))) |
| return true; |
| |
| sk->sk_prot->enter_memory_pressure(sk); |
| sk_stream_moderate_sndbuf(sk); |
| return false; |
| } |
| |
| static struct mptcp_data_frag * |
| mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag, |
| int orig_offset) |
| { |
| int offset = ALIGN(orig_offset, sizeof(long)); |
| struct mptcp_data_frag *dfrag; |
| |
| dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset); |
| dfrag->data_len = 0; |
| dfrag->data_seq = msk->write_seq; |
| dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag); |
| dfrag->offset = offset + sizeof(struct mptcp_data_frag); |
| dfrag->page = pfrag->page; |
| |
| return dfrag; |
| } |
| |
| static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, |
| struct msghdr *msg, struct mptcp_data_frag *dfrag, |
| long *timeo, int *pmss_now, |
| int *ps_goal) |
| { |
| int mss_now, avail_size, size_goal, offset, ret, frag_truesize = 0; |
| bool dfrag_collapsed, can_collapse = false; |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct mptcp_ext *mpext = NULL; |
| bool retransmission = !!dfrag; |
| struct sk_buff *skb, *tail; |
| struct page_frag *pfrag; |
| struct page *page; |
| u64 *write_seq; |
| size_t psize; |
| |
| /* use the mptcp page cache so that we can easily move the data |
| * from one substream to another, but do per subflow memory accounting |
| * Note: pfrag is used only !retransmission, but the compiler if |
| * fooled into a warning if we don't init here |
| */ |
| pfrag = sk_page_frag(sk); |
| while ((!retransmission && !mptcp_page_frag_refill(ssk, pfrag)) || |
| !mptcp_ext_cache_refill(msk)) { |
| ret = sk_stream_wait_memory(ssk, timeo); |
| if (ret) |
| return ret; |
| |
| /* if sk_stream_wait_memory() sleeps snd_una can change |
| * significantly, refresh the rtx queue |
| */ |
| mptcp_clean_una(sk); |
| |
| if (unlikely(__mptcp_needs_tcp_fallback(msk))) |
| return 0; |
| } |
| if (!retransmission) { |
| write_seq = &msk->write_seq; |
| page = pfrag->page; |
| } else { |
| write_seq = &dfrag->data_seq; |
| page = dfrag->page; |
| } |
| |
| /* compute copy limit */ |
| mss_now = tcp_send_mss(ssk, &size_goal, msg->msg_flags); |
| *pmss_now = mss_now; |
| *ps_goal = size_goal; |
| avail_size = size_goal; |
| skb = tcp_write_queue_tail(ssk); |
| if (skb) { |
| mpext = skb_ext_find(skb, SKB_EXT_MPTCP); |
| |
| /* Limit the write to the size available in the |
| * current skb, if any, so that we create at most a new skb. |
| * Explicitly tells TCP internals to avoid collapsing on later |
| * queue management operation, to avoid breaking the ext <-> |
| * SSN association set here |
| */ |
| can_collapse = (size_goal - skb->len > 0) && |
| mptcp_skb_can_collapse_to(*write_seq, skb, mpext); |
| if (!can_collapse) |
| TCP_SKB_CB(skb)->eor = 1; |
| else |
| avail_size = size_goal - skb->len; |
| } |
| |
| if (!retransmission) { |
| /* reuse tail pfrag, if possible, or carve a new one from the |
| * page allocator |
| */ |
| dfrag = mptcp_rtx_tail(sk); |
| offset = pfrag->offset; |
| dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag); |
| if (!dfrag_collapsed) { |
| dfrag = mptcp_carve_data_frag(msk, pfrag, offset); |
| offset = dfrag->offset; |
| frag_truesize = dfrag->overhead; |
| } |
| psize = min_t(size_t, pfrag->size - offset, avail_size); |
| |
| /* Copy to page */ |
| pr_debug("left=%zu", msg_data_left(msg)); |
| psize = copy_page_from_iter(pfrag->page, offset, |
| min_t(size_t, msg_data_left(msg), |
| psize), |
| &msg->msg_iter); |
| pr_debug("left=%zu", msg_data_left(msg)); |
| if (!psize) |
| return -EINVAL; |
| |
| if (!sk_wmem_schedule(sk, psize + dfrag->overhead)) |
| return -ENOMEM; |
| } else { |
| offset = dfrag->offset; |
| psize = min_t(size_t, dfrag->data_len, avail_size); |
| } |
| |
| /* tell the TCP stack to delay the push so that we can safely |
| * access the skb after the sendpages call |
| */ |
| ret = do_tcp_sendpages(ssk, page, offset, psize, |
| msg->msg_flags | MSG_SENDPAGE_NOTLAST); |
| if (ret <= 0) |
| return ret; |
| |
| frag_truesize += ret; |
| if (!retransmission) { |
| if (unlikely(ret < psize)) |
| iov_iter_revert(&msg->msg_iter, psize - ret); |
| |
| /* send successful, keep track of sent data for mptcp-level |
| * retransmission |
| */ |
| dfrag->data_len += ret; |
| if (!dfrag_collapsed) { |
| get_page(dfrag->page); |
| list_add_tail(&dfrag->list, &msk->rtx_queue); |
| sk_wmem_queued_add(sk, frag_truesize); |
| } else { |
| sk_wmem_queued_add(sk, ret); |
| } |
| |
| /* charge data on mptcp rtx queue to the master socket |
| * Note: we charge such data both to sk and ssk |
| */ |
| sk->sk_forward_alloc -= frag_truesize; |
| } |
| |
| /* if the tail skb extension is still the cached one, collapsing |
| * really happened. Note: we can't check for 'same skb' as the sk_buff |
| * hdr on tail can be transmitted, freed and re-allocated by the |
| * do_tcp_sendpages() call |
| */ |
| tail = tcp_write_queue_tail(ssk); |
| if (mpext && tail && mpext == skb_ext_find(tail, SKB_EXT_MPTCP)) { |
| WARN_ON_ONCE(!can_collapse); |
| mpext->data_len += ret; |
| goto out; |
| } |
| |
| skb = tcp_write_queue_tail(ssk); |
| mpext = __skb_ext_set(skb, SKB_EXT_MPTCP, msk->cached_ext); |
| msk->cached_ext = NULL; |
| |
| memset(mpext, 0, sizeof(*mpext)); |
| mpext->data_seq = *write_seq; |
| mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq; |
| mpext->data_len = ret; |
| mpext->use_map = 1; |
| mpext->dsn64 = 1; |
| |
| pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d", |
| mpext->data_seq, mpext->subflow_seq, mpext->data_len, |
| mpext->dsn64); |
| |
| out: |
| if (!retransmission) |
| pfrag->offset += frag_truesize; |
| *write_seq += ret; |
| mptcp_subflow_ctx(ssk)->rel_write_seq += ret; |
| |
| return ret; |
| } |
| |
| static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) |
| { |
| struct mptcp_subflow_context *subflow; |
| struct sock *backup = NULL; |
| |
| sock_owned_by_me((const struct sock *)msk); |
| |
| mptcp_for_each_subflow(msk, subflow) { |
| struct sock *ssk = mptcp_subflow_tcp_sock(subflow); |
| |
| if (!sk_stream_memory_free(ssk)) { |
| struct socket *sock = ssk->sk_socket; |
| |
| if (sock) { |
| clear_bit(MPTCP_SEND_SPACE, &msk->flags); |
| smp_mb__after_atomic(); |
| |
| /* enables sk->write_space() callbacks */ |
| set_bit(SOCK_NOSPACE, &sock->flags); |
| } |
| |
| return NULL; |
| } |
| |
| if (subflow->backup) { |
| if (!backup) |
| backup = ssk; |
| |
| continue; |
| } |
| |
| return ssk; |
| } |
| |
| return backup; |
| } |
| |
| static void ssk_check_wmem(struct mptcp_sock *msk, struct sock *ssk) |
| { |
| struct socket *sock; |
| |
| if (likely(sk_stream_is_writeable(ssk))) |
| return; |
| |
| sock = READ_ONCE(ssk->sk_socket); |
| |
| if (sock) { |
| clear_bit(MPTCP_SEND_SPACE, &msk->flags); |
| smp_mb__after_atomic(); |
| /* set NOSPACE only after clearing SEND_SPACE flag */ |
| set_bit(SOCK_NOSPACE, &sock->flags); |
| } |
| } |
| |
| static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) |
| { |
| int mss_now = 0, size_goal = 0, ret = 0; |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct socket *ssock; |
| size_t copied = 0; |
| struct sock *ssk; |
| long timeo; |
| |
| if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL)) |
| return -EOPNOTSUPP; |
| |
| lock_sock(sk); |
| |
| timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); |
| |
| if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { |
| ret = sk_stream_wait_connect(sk, &timeo); |
| if (ret) |
| goto out; |
| } |
| |
| ssock = __mptcp_tcp_fallback(msk); |
| if (unlikely(ssock)) { |
| fallback: |
| pr_debug("fallback passthrough"); |
| ret = sock_sendmsg(ssock, msg); |
| return ret >= 0 ? ret + copied : (copied ? copied : ret); |
| } |
| |
| mptcp_clean_una(sk); |
| |
| __mptcp_flush_join_list(msk); |
| ssk = mptcp_subflow_get_send(msk); |
| while (!sk_stream_memory_free(sk) || !ssk) { |
| ret = sk_stream_wait_memory(sk, &timeo); |
| if (ret) |
| goto out; |
| |
| mptcp_clean_una(sk); |
| |
| ssk = mptcp_subflow_get_send(msk); |
| if (list_empty(&msk->conn_list)) { |
| ret = -ENOTCONN; |
| goto out; |
| } |
| } |
| |
| pr_debug("conn_list->subflow=%p", ssk); |
| |
| lock_sock(ssk); |
| while (msg_data_left(msg)) { |
| ret = mptcp_sendmsg_frag(sk, ssk, msg, NULL, &timeo, &mss_now, |
| &size_goal); |
| if (ret < 0) |
| break; |
| if (ret == 0 && unlikely(__mptcp_needs_tcp_fallback(msk))) { |
| release_sock(ssk); |
| ssock = __mptcp_tcp_fallback(msk); |
| goto fallback; |
| } |
| |
| copied += ret; |
| } |
| |
| mptcp_set_timeout(sk, ssk); |
| if (copied) { |
| ret = copied; |
| tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle, |
| size_goal); |
| |
| /* start the timer, if it's not pending */ |
| if (!mptcp_timer_pending(sk)) |
| mptcp_reset_timer(sk); |
| } |
| |
| ssk_check_wmem(msk, ssk); |
| release_sock(ssk); |
| out: |
| release_sock(sk); |
| return ret; |
| } |
| |
| static void mptcp_wait_data(struct sock *sk, long *timeo) |
| { |
| DEFINE_WAIT_FUNC(wait, woken_wake_function); |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| add_wait_queue(sk_sleep(sk), &wait); |
| sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); |
| |
| sk_wait_event(sk, timeo, |
| test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait); |
| |
| sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); |
| remove_wait_queue(sk_sleep(sk), &wait); |
| } |
| |
| static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, |
| struct msghdr *msg, |
| size_t len) |
| { |
| struct sock *sk = (struct sock *)msk; |
| struct sk_buff *skb; |
| int copied = 0; |
| |
| while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) { |
| u32 offset = MPTCP_SKB_CB(skb)->offset; |
| u32 data_len = skb->len - offset; |
| u32 count = min_t(size_t, len - copied, data_len); |
| int err; |
| |
| err = skb_copy_datagram_msg(skb, offset, msg, count); |
| if (unlikely(err < 0)) { |
| if (!copied) |
| return err; |
| break; |
| } |
| |
| copied += count; |
| |
| if (count < data_len) { |
| MPTCP_SKB_CB(skb)->offset += count; |
| break; |
| } |
| |
| __skb_unlink(skb, &sk->sk_receive_queue); |
| __kfree_skb(skb); |
| |
| if (copied >= len) |
| break; |
| } |
| |
| return copied; |
| } |
| |
| static bool __mptcp_move_skbs(struct mptcp_sock *msk) |
| { |
| unsigned int moved = 0; |
| bool done; |
| |
| do { |
| struct sock *ssk = mptcp_subflow_recv_lookup(msk); |
| |
| if (!ssk) |
| break; |
| |
| lock_sock(ssk); |
| done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); |
| release_sock(ssk); |
| } while (!done); |
| |
| return moved > 0; |
| } |
| |
| static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, |
| int nonblock, int flags, int *addr_len) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct socket *ssock; |
| int copied = 0; |
| int target; |
| long timeo; |
| |
| if (msg->msg_flags & ~(MSG_WAITALL | MSG_DONTWAIT)) |
| return -EOPNOTSUPP; |
| |
| lock_sock(sk); |
| ssock = __mptcp_tcp_fallback(msk); |
| if (unlikely(ssock)) { |
| fallback: |
| pr_debug("fallback-read subflow=%p", |
| mptcp_subflow_ctx(ssock->sk)); |
| copied = sock_recvmsg(ssock, msg, flags); |
| return copied; |
| } |
| |
| timeo = sock_rcvtimeo(sk, nonblock); |
| |
| len = min_t(size_t, len, INT_MAX); |
| target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); |
| __mptcp_flush_join_list(msk); |
| |
| while (len > (size_t)copied) { |
| int bytes_read; |
| |
| bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied); |
| if (unlikely(bytes_read < 0)) { |
| if (!copied) |
| copied = bytes_read; |
| goto out_err; |
| } |
| |
| copied += bytes_read; |
| |
| if (skb_queue_empty(&sk->sk_receive_queue) && |
| __mptcp_move_skbs(msk)) |
| continue; |
| |
| /* only the master socket status is relevant here. The exit |
| * conditions mirror closely tcp_recvmsg() |
| */ |
| if (copied >= target) |
| break; |
| |
| if (copied) { |
| if (sk->sk_err || |
| sk->sk_state == TCP_CLOSE || |
| (sk->sk_shutdown & RCV_SHUTDOWN) || |
| !timeo || |
| signal_pending(current)) |
| break; |
| } else { |
| if (sk->sk_err) { |
| copied = sock_error(sk); |
| break; |
| } |
| |
| if (sk->sk_shutdown & RCV_SHUTDOWN) |
| break; |
| |
| if (sk->sk_state == TCP_CLOSE) { |
| copied = -ENOTCONN; |
| break; |
| } |
| |
| if (!timeo) { |
| copied = -EAGAIN; |
| break; |
| } |
| |
| if (signal_pending(current)) { |
| copied = sock_intr_errno(timeo); |
| break; |
| } |
| } |
| |
| pr_debug("block timeout %ld", timeo); |
| mptcp_wait_data(sk, &timeo); |
| if (unlikely(__mptcp_tcp_fallback(msk))) |
| goto fallback; |
| } |
| |
| if (skb_queue_empty(&sk->sk_receive_queue)) { |
| /* entire backlog drained, clear DATA_READY. */ |
| clear_bit(MPTCP_DATA_READY, &msk->flags); |
| |
| /* .. race-breaker: ssk might have gotten new data |
| * after last __mptcp_move_skbs() returned false. |
| */ |
| if (unlikely(__mptcp_move_skbs(msk))) |
| set_bit(MPTCP_DATA_READY, &msk->flags); |
| } else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) { |
| /* data to read but mptcp_wait_data() cleared DATA_READY */ |
| set_bit(MPTCP_DATA_READY, &msk->flags); |
| } |
| out_err: |
| release_sock(sk); |
| return copied; |
| } |
| |
| static void mptcp_retransmit_handler(struct sock *sk) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| if (atomic64_read(&msk->snd_una) == msk->write_seq) { |
| mptcp_stop_timer(sk); |
| } else { |
| set_bit(MPTCP_WORK_RTX, &msk->flags); |
| if (schedule_work(&msk->work)) |
| sock_hold(sk); |
| } |
| } |
| |
| static void mptcp_retransmit_timer(struct timer_list *t) |
| { |
| struct inet_connection_sock *icsk = from_timer(icsk, t, |
| icsk_retransmit_timer); |
| struct sock *sk = &icsk->icsk_inet.sk; |
| |
| bh_lock_sock(sk); |
| if (!sock_owned_by_user(sk)) { |
| mptcp_retransmit_handler(sk); |
| } else { |
| /* delegate our work to tcp_release_cb() */ |
| if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED, |
| &sk->sk_tsq_flags)) |
| sock_hold(sk); |
| } |
| bh_unlock_sock(sk); |
| sock_put(sk); |
| } |
| |
| /* Find an idle subflow. Return NULL if there is unacked data at tcp |
| * level. |
| * |
| * A backup subflow is returned only if that is the only kind available. |
| */ |
| static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk) |
| { |
| struct mptcp_subflow_context *subflow; |
| struct sock *backup = NULL; |
| |
| sock_owned_by_me((const struct sock *)msk); |
| |
| mptcp_for_each_subflow(msk, subflow) { |
| struct sock *ssk = mptcp_subflow_tcp_sock(subflow); |
| |
| /* still data outstanding at TCP level? Don't retransmit. */ |
| if (!tcp_write_queue_empty(ssk)) |
| return NULL; |
| |
| if (subflow->backup) { |
| if (!backup) |
| backup = ssk; |
| continue; |
| } |
| |
| return ssk; |
| } |
| |
| return backup; |
| } |
| |
| /* subflow sockets can be either outgoing (connect) or incoming |
| * (accept). |
| * |
| * Outgoing subflows use in-kernel sockets. |
| * Incoming subflows do not have their own 'struct socket' allocated, |
| * so we need to use tcp_close() after detaching them from the mptcp |
| * parent socket. |
| */ |
| static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, |
| struct mptcp_subflow_context *subflow, |
| long timeout) |
| { |
| struct socket *sock = READ_ONCE(ssk->sk_socket); |
| |
| list_del(&subflow->node); |
| |
| if (sock && sock != sk->sk_socket) { |
| /* outgoing subflow */ |
| sock_release(sock); |
| } else { |
| /* incoming subflow */ |
| tcp_close(ssk, timeout); |
| } |
| } |
| |
| static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) |
| { |
| return 0; |
| } |
| |
| static void mptcp_check_for_eof(struct mptcp_sock *msk) |
| { |
| struct mptcp_subflow_context *subflow; |
| struct sock *sk = (struct sock *)msk; |
| int receivers = 0; |
| |
| mptcp_for_each_subflow(msk, subflow) |
| receivers += !subflow->rx_eof; |
| |
| if (!receivers && !(sk->sk_shutdown & RCV_SHUTDOWN)) { |
| /* hopefully temporary hack: propagate shutdown status |
| * to msk, when all subflows agree on it |
| */ |
| sk->sk_shutdown |= RCV_SHUTDOWN; |
| |
| smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ |
| set_bit(MPTCP_DATA_READY, &msk->flags); |
| sk->sk_data_ready(sk); |
| } |
| } |
| |
| static void mptcp_worker(struct work_struct *work) |
| { |
| struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); |
| struct sock *ssk, *sk = &msk->sk.icsk_inet.sk; |
| int orig_len, orig_offset, ret, mss_now = 0, size_goal = 0; |
| struct mptcp_data_frag *dfrag; |
| u64 orig_write_seq; |
| size_t copied = 0; |
| struct msghdr msg; |
| long timeo = 0; |
| |
| lock_sock(sk); |
| mptcp_clean_una(sk); |
| __mptcp_flush_join_list(msk); |
| __mptcp_move_skbs(msk); |
| |
| if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) |
| mptcp_check_for_eof(msk); |
| |
| if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) |
| goto unlock; |
| |
| dfrag = mptcp_rtx_head(sk); |
| if (!dfrag) |
| goto unlock; |
| |
| ssk = mptcp_subflow_get_retrans(msk); |
| if (!ssk) |
| goto reset_unlock; |
| |
| lock_sock(ssk); |
| |
| msg.msg_flags = MSG_DONTWAIT; |
| orig_len = dfrag->data_len; |
| orig_offset = dfrag->offset; |
| orig_write_seq = dfrag->data_seq; |
| while (dfrag->data_len > 0) { |
| ret = mptcp_sendmsg_frag(sk, ssk, &msg, dfrag, &timeo, &mss_now, |
| &size_goal); |
| if (ret < 0) |
| break; |
| |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); |
| copied += ret; |
| dfrag->data_len -= ret; |
| dfrag->offset += ret; |
| } |
| if (copied) |
| tcp_push(ssk, msg.msg_flags, mss_now, tcp_sk(ssk)->nonagle, |
| size_goal); |
| |
| dfrag->data_seq = orig_write_seq; |
| dfrag->offset = orig_offset; |
| dfrag->data_len = orig_len; |
| |
| mptcp_set_timeout(sk, ssk); |
| release_sock(ssk); |
| |
| reset_unlock: |
| if (!mptcp_timer_pending(sk)) |
| mptcp_reset_timer(sk); |
| |
| unlock: |
| release_sock(sk); |
| sock_put(sk); |
| } |
| |
| static int __mptcp_init_sock(struct sock *sk) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| spin_lock_init(&msk->join_list_lock); |
| |
| INIT_LIST_HEAD(&msk->conn_list); |
| INIT_LIST_HEAD(&msk->join_list); |
| INIT_LIST_HEAD(&msk->rtx_queue); |
| __set_bit(MPTCP_SEND_SPACE, &msk->flags); |
| INIT_WORK(&msk->work, mptcp_worker); |
| |
| msk->first = NULL; |
| inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; |
| |
| mptcp_pm_data_init(msk); |
| |
| /* re-use the csk retrans timer for MPTCP-level retrans */ |
| timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0); |
| |
| return 0; |
| } |
| |
| static int mptcp_init_sock(struct sock *sk) |
| { |
| struct net *net = sock_net(sk); |
| int ret; |
| |
| if (!mptcp_is_enabled(net)) |
| return -ENOPROTOOPT; |
| |
| if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) |
| return -ENOMEM; |
| |
| ret = __mptcp_init_sock(sk); |
| if (ret) |
| return ret; |
| |
| sk_sockets_allocated_inc(sk); |
| sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[2]; |
| |
| return 0; |
| } |
| |
| static void __mptcp_clear_xmit(struct sock *sk) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct mptcp_data_frag *dtmp, *dfrag; |
| |
| sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer); |
| |
| list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) |
| dfrag_clear(sk, dfrag); |
| } |
| |
| static void mptcp_cancel_work(struct sock *sk) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| if (cancel_work_sync(&msk->work)) |
| sock_put(sk); |
| } |
| |
| static void mptcp_subflow_shutdown(struct sock *ssk, int how, |
| bool data_fin_tx_enable, u64 data_fin_tx_seq) |
| { |
| lock_sock(ssk); |
| |
| switch (ssk->sk_state) { |
| case TCP_LISTEN: |
| if (!(how & RCV_SHUTDOWN)) |
| break; |
| /* fall through */ |
| case TCP_SYN_SENT: |
| tcp_disconnect(ssk, O_NONBLOCK); |
| break; |
| default: |
| if (data_fin_tx_enable) { |
| struct mptcp_subflow_context *subflow; |
| |
| subflow = mptcp_subflow_ctx(ssk); |
| subflow->data_fin_tx_seq = data_fin_tx_seq; |
| subflow->data_fin_tx_enable = 1; |
| } |
| |
| ssk->sk_shutdown |= how; |
| tcp_shutdown(ssk, how); |
| break; |
| } |
| |
| /* Wake up anyone sleeping in poll. */ |
| ssk->sk_state_change(ssk); |
| release_sock(ssk); |
| } |
| |
| /* Called with msk lock held, releases such lock before returning */ |
| static void mptcp_close(struct sock *sk, long timeout) |
| { |
| struct mptcp_subflow_context *subflow, *tmp; |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| LIST_HEAD(conn_list); |
| u64 data_fin_tx_seq; |
| |
| lock_sock(sk); |
| |
| mptcp_token_destroy(msk->token); |
| inet_sk_state_store(sk, TCP_CLOSE); |
| |
| __mptcp_flush_join_list(msk); |
| |
| list_splice_init(&msk->conn_list, &conn_list); |
| |
| data_fin_tx_seq = msk->write_seq; |
| |
| __mptcp_clear_xmit(sk); |
| |
| release_sock(sk); |
| |
| list_for_each_entry_safe(subflow, tmp, &conn_list, node) { |
| struct sock *ssk = mptcp_subflow_tcp_sock(subflow); |
| |
| subflow->data_fin_tx_seq = data_fin_tx_seq; |
| subflow->data_fin_tx_enable = 1; |
| __mptcp_close_ssk(sk, ssk, subflow, timeout); |
| } |
| |
| mptcp_cancel_work(sk); |
| mptcp_pm_close(msk); |
| |
| __skb_queue_purge(&sk->sk_receive_queue); |
| |
| sk_common_release(sk); |
| } |
| |
| static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) |
| { |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| const struct ipv6_pinfo *ssk6 = inet6_sk(ssk); |
| struct ipv6_pinfo *msk6 = inet6_sk(msk); |
| |
| msk->sk_v6_daddr = ssk->sk_v6_daddr; |
| msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr; |
| |
| if (msk6 && ssk6) { |
| msk6->saddr = ssk6->saddr; |
| msk6->flow_label = ssk6->flow_label; |
| } |
| #endif |
| |
| inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num; |
| inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport; |
| inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport; |
| inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr; |
| inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr; |
| inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr; |
| } |
| |
| static int mptcp_disconnect(struct sock *sk, int flags) |
| { |
| lock_sock(sk); |
| __mptcp_clear_xmit(sk); |
| release_sock(sk); |
| mptcp_cancel_work(sk); |
| return tcp_disconnect(sk, flags); |
| } |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk) |
| { |
| unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo); |
| |
| return (struct ipv6_pinfo *)(((u8 *)sk) + offset); |
| } |
| #endif |
| |
| struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req) |
| { |
| struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC); |
| struct mptcp_sock *msk; |
| u64 ack_seq; |
| |
| if (!nsk) |
| return NULL; |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| if (nsk->sk_family == AF_INET6) |
| inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); |
| #endif |
| |
| __mptcp_init_sock(nsk); |
| |
| msk = mptcp_sk(nsk); |
| msk->local_key = subflow_req->local_key; |
| msk->token = subflow_req->token; |
| msk->subflow = NULL; |
| |
| if (unlikely(mptcp_token_new_accept(subflow_req->token, nsk))) { |
| bh_unlock_sock(nsk); |
| |
| /* we can't call into mptcp_close() here - possible BH context |
| * free the sock directly |
| */ |
| nsk->sk_prot->destroy(nsk); |
| sk_free(nsk); |
| return NULL; |
| } |
| |
| msk->write_seq = subflow_req->idsn + 1; |
| atomic64_set(&msk->snd_una, msk->write_seq); |
| if (subflow_req->remote_key_valid) { |
| msk->can_ack = true; |
| msk->remote_key = subflow_req->remote_key; |
| mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq); |
| ack_seq++; |
| msk->ack_seq = ack_seq; |
| } |
| |
| /* will be fully established after successful MPC subflow creation */ |
| inet_sk_state_store(nsk, TCP_SYN_RECV); |
| bh_unlock_sock(nsk); |
| |
| /* keep a single reference */ |
| __sock_put(nsk); |
| return nsk; |
| } |
| |
| static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, |
| bool kern) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct socket *listener; |
| struct sock *newsk; |
| |
| listener = __mptcp_nmpc_socket(msk); |
| if (WARN_ON_ONCE(!listener)) { |
| *err = -EINVAL; |
| return NULL; |
| } |
| |
| pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk)); |
| newsk = inet_csk_accept(listener->sk, flags, err, kern); |
| if (!newsk) |
| return NULL; |
| |
| pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk)); |
| |
| if (sk_is_mptcp(newsk)) { |
| struct mptcp_subflow_context *subflow; |
| struct sock *new_mptcp_sock; |
| struct sock *ssk = newsk; |
| |
| subflow = mptcp_subflow_ctx(newsk); |
| new_mptcp_sock = subflow->conn; |
| |
| /* is_mptcp should be false if subflow->conn is missing, see |
| * subflow_syn_recv_sock() |
| */ |
| if (WARN_ON_ONCE(!new_mptcp_sock)) { |
| tcp_sk(newsk)->is_mptcp = 0; |
| return newsk; |
| } |
| |
| /* acquire the 2nd reference for the owning socket */ |
| sock_hold(new_mptcp_sock); |
| |
| local_bh_disable(); |
| bh_lock_sock(new_mptcp_sock); |
| msk = mptcp_sk(new_mptcp_sock); |
| msk->first = newsk; |
| |
| newsk = new_mptcp_sock; |
| mptcp_copy_inaddrs(newsk, ssk); |
| list_add(&subflow->node, &msk->conn_list); |
| |
| bh_unlock_sock(new_mptcp_sock); |
| |
| __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK); |
| local_bh_enable(); |
| } else { |
| MPTCP_INC_STATS(sock_net(sk), |
| MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); |
| } |
| |
| return newsk; |
| } |
| |
| static void mptcp_destroy(struct sock *sk) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| if (msk->cached_ext) |
| __skb_ext_put(msk->cached_ext); |
| |
| sk_sockets_allocated_dec(sk); |
| } |
| |
| static int mptcp_setsockopt(struct sock *sk, int level, int optname, |
| char __user *optval, unsigned int optlen) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct socket *ssock; |
| |
| pr_debug("msk=%p", msk); |
| |
| /* @@ the meaning of setsockopt() when the socket is connected and |
| * there are multiple subflows is not yet defined. It is up to the |
| * MPTCP-level socket to configure the subflows until the subflow |
| * is in TCP fallback, when TCP socket options are passed through |
| * to the one remaining subflow. |
| */ |
| lock_sock(sk); |
| ssock = __mptcp_tcp_fallback(msk); |
| if (ssock) |
| return tcp_setsockopt(ssock->sk, level, optname, optval, |
| optlen); |
| |
| release_sock(sk); |
| |
| return -EOPNOTSUPP; |
| } |
| |
| static int mptcp_getsockopt(struct sock *sk, int level, int optname, |
| char __user *optval, int __user *option) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct socket *ssock; |
| |
| pr_debug("msk=%p", msk); |
| |
| /* @@ the meaning of setsockopt() when the socket is connected and |
| * there are multiple subflows is not yet defined. It is up to the |
| * MPTCP-level socket to configure the subflows until the subflow |
| * is in TCP fallback, when socket options are passed through |
| * to the one remaining subflow. |
| */ |
| lock_sock(sk); |
| ssock = __mptcp_tcp_fallback(msk); |
| if (ssock) |
| return tcp_getsockopt(ssock->sk, level, optname, optval, |
| option); |
| |
| release_sock(sk); |
| |
| return -EOPNOTSUPP; |
| } |
| |
| #define MPTCP_DEFERRED_ALL (TCPF_DELACK_TIMER_DEFERRED | \ |
| TCPF_WRITE_TIMER_DEFERRED) |
| |
| /* this is very alike tcp_release_cb() but we must handle differently a |
| * different set of events |
| */ |
| static void mptcp_release_cb(struct sock *sk) |
| { |
| unsigned long flags, nflags; |
| |
| do { |
| flags = sk->sk_tsq_flags; |
| if (!(flags & MPTCP_DEFERRED_ALL)) |
| return; |
| nflags = flags & ~MPTCP_DEFERRED_ALL; |
| } while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags); |
| |
| sock_release_ownership(sk); |
| |
| if (flags & TCPF_DELACK_TIMER_DEFERRED) { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct sock *ssk; |
| |
| ssk = mptcp_subflow_recv_lookup(msk); |
| if (!ssk || !schedule_work(&msk->work)) |
| __sock_put(sk); |
| } |
| |
| if (flags & TCPF_WRITE_TIMER_DEFERRED) { |
| mptcp_retransmit_handler(sk); |
| __sock_put(sk); |
| } |
| } |
| |
| static int mptcp_get_port(struct sock *sk, unsigned short snum) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct socket *ssock; |
| |
| ssock = __mptcp_nmpc_socket(msk); |
| pr_debug("msk=%p, subflow=%p", msk, ssock); |
| if (WARN_ON_ONCE(!ssock)) |
| return -EINVAL; |
| |
| return inet_csk_get_port(ssock->sk, snum); |
| } |
| |
| void mptcp_finish_connect(struct sock *ssk) |
| { |
| struct mptcp_subflow_context *subflow; |
| struct mptcp_sock *msk; |
| struct sock *sk; |
| u64 ack_seq; |
| |
| subflow = mptcp_subflow_ctx(ssk); |
| sk = subflow->conn; |
| msk = mptcp_sk(sk); |
| |
| if (!subflow->mp_capable) { |
| MPTCP_INC_STATS(sock_net(sk), |
| MPTCP_MIB_MPCAPABLEACTIVEFALLBACK); |
| return; |
| } |
| |
| pr_debug("msk=%p, token=%u", sk, subflow->token); |
| |
| mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq); |
| ack_seq++; |
| subflow->map_seq = ack_seq; |
| subflow->map_subflow_seq = 1; |
| subflow->rel_write_seq = 1; |
| |
| /* the socket is not connected yet, no msk/subflow ops can access/race |
| * accessing the field below |
| */ |
| WRITE_ONCE(msk->remote_key, subflow->remote_key); |
| WRITE_ONCE(msk->local_key, subflow->local_key); |
| WRITE_ONCE(msk->token, subflow->token); |
| WRITE_ONCE(msk->write_seq, subflow->idsn + 1); |
| WRITE_ONCE(msk->ack_seq, ack_seq); |
| WRITE_ONCE(msk->can_ack, 1); |
| atomic64_set(&msk->snd_una, msk->write_seq); |
| |
| mptcp_pm_new_connection(msk, 0); |
| } |
| |
| static void mptcp_sock_graft(struct sock *sk, struct socket *parent) |
| { |
| write_lock_bh(&sk->sk_callback_lock); |
| rcu_assign_pointer(sk->sk_wq, &parent->wq); |
| sk_set_socket(sk, parent); |
| sk->sk_uid = SOCK_INODE(parent)->i_uid; |
| write_unlock_bh(&sk->sk_callback_lock); |
| } |
| |
| bool mptcp_finish_join(struct sock *sk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| struct sock *parent = (void *)msk; |
| struct socket *parent_sock; |
| bool ret; |
| |
| pr_debug("msk=%p, subflow=%p", msk, subflow); |
| |
| /* mptcp socket already closing? */ |
| if (inet_sk_state_load(parent) != TCP_ESTABLISHED) |
| return false; |
| |
| if (!msk->pm.server_side) |
| return true; |
| |
| /* passive connection, attach to msk socket */ |
| parent_sock = READ_ONCE(parent->sk_socket); |
| if (parent_sock && !sk->sk_socket) |
| mptcp_sock_graft(sk, parent_sock); |
| |
| ret = mptcp_pm_allow_new_subflow(msk); |
| if (ret) { |
| /* active connections are already on conn_list */ |
| spin_lock_bh(&msk->join_list_lock); |
| if (!WARN_ON_ONCE(!list_empty(&subflow->node))) |
| list_add_tail(&subflow->node, &msk->join_list); |
| spin_unlock_bh(&msk->join_list_lock); |
| } |
| return ret; |
| } |
| |
| bool mptcp_sk_is_subflow(const struct sock *sk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| |
| return subflow->mp_join == 1; |
| } |
| |
| static bool mptcp_memory_free(const struct sock *sk, int wake) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| return wake ? test_bit(MPTCP_SEND_SPACE, &msk->flags) : true; |
| } |
| |
| static struct proto mptcp_prot = { |
| .name = "MPTCP", |
| .owner = THIS_MODULE, |
| .init = mptcp_init_sock, |
| .disconnect = mptcp_disconnect, |
| .close = mptcp_close, |
| .accept = mptcp_accept, |
| .setsockopt = mptcp_setsockopt, |
| .getsockopt = mptcp_getsockopt, |
| .shutdown = tcp_shutdown, |
| .destroy = mptcp_destroy, |
| .sendmsg = mptcp_sendmsg, |
| .recvmsg = mptcp_recvmsg, |
| .release_cb = mptcp_release_cb, |
| .hash = inet_hash, |
| .unhash = inet_unhash, |
| .get_port = mptcp_get_port, |
| .sockets_allocated = &mptcp_sockets_allocated, |
| .memory_allocated = &tcp_memory_allocated, |
| .memory_pressure = &tcp_memory_pressure, |
| .stream_memory_free = mptcp_memory_free, |
| .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), |
| .sysctl_mem = sysctl_tcp_mem, |
| .obj_size = sizeof(struct mptcp_sock), |
| .no_autobind = true, |
| }; |
| |
| static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sock->sk); |
| struct socket *ssock; |
| int err; |
| |
| lock_sock(sock->sk); |
| ssock = __mptcp_socket_create(msk, MPTCP_SAME_STATE); |
| if (IS_ERR(ssock)) { |
| err = PTR_ERR(ssock); |
| goto unlock; |
| } |
| |
| err = ssock->ops->bind(ssock, uaddr, addr_len); |
| if (!err) |
| mptcp_copy_inaddrs(sock->sk, ssock->sk); |
| |
| unlock: |
| release_sock(sock->sk); |
| return err; |
| } |
| |
| static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr, |
| int addr_len, int flags) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sock->sk); |
| struct socket *ssock; |
| int err; |
| |
| lock_sock(sock->sk); |
| ssock = __mptcp_socket_create(msk, TCP_SYN_SENT); |
| if (IS_ERR(ssock)) { |
| err = PTR_ERR(ssock); |
| goto unlock; |
| } |
| |
| #ifdef CONFIG_TCP_MD5SIG |
| /* no MPTCP if MD5SIG is enabled on this socket or we may run out of |
| * TCP option space. |
| */ |
| if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info)) |
| mptcp_subflow_ctx(ssock->sk)->request_mptcp = 0; |
| #endif |
| |
| err = ssock->ops->connect(ssock, uaddr, addr_len, flags); |
| inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); |
| mptcp_copy_inaddrs(sock->sk, ssock->sk); |
| |
| unlock: |
| release_sock(sock->sk); |
| return err; |
| } |
| |
| static int mptcp_v4_getname(struct socket *sock, struct sockaddr *uaddr, |
| int peer) |
| { |
| if (sock->sk->sk_prot == &tcp_prot) { |
| /* we are being invoked from __sys_accept4, after |
| * mptcp_accept() has just accepted a non-mp-capable |
| * flow: sk is a tcp_sk, not an mptcp one. |
| * |
| * Hand the socket over to tcp so all further socket ops |
| * bypass mptcp. |
| */ |
| sock->ops = &inet_stream_ops; |
| } |
| |
| return inet_getname(sock, uaddr, peer); |
| } |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| static int mptcp_v6_getname(struct socket *sock, struct sockaddr *uaddr, |
| int peer) |
| { |
| if (sock->sk->sk_prot == &tcpv6_prot) { |
| /* we are being invoked from __sys_accept4 after |
| * mptcp_accept() has accepted a non-mp-capable |
| * subflow: sk is a tcp_sk, not mptcp. |
| * |
| * Hand the socket over to tcp so all further |
| * socket ops bypass mptcp. |
| */ |
| sock->ops = &inet6_stream_ops; |
| } |
| |
| return inet6_getname(sock, uaddr, peer); |
| } |
| #endif |
| |
| static int mptcp_listen(struct socket *sock, int backlog) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sock->sk); |
| struct socket *ssock; |
| int err; |
| |
| pr_debug("msk=%p", msk); |
| |
| lock_sock(sock->sk); |
| ssock = __mptcp_socket_create(msk, TCP_LISTEN); |
| if (IS_ERR(ssock)) { |
| err = PTR_ERR(ssock); |
| goto unlock; |
| } |
| |
| err = ssock->ops->listen(ssock, backlog); |
| inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); |
| if (!err) |
| mptcp_copy_inaddrs(sock->sk, ssock->sk); |
| |
| unlock: |
| release_sock(sock->sk); |
| return err; |
| } |
| |
| static bool is_tcp_proto(const struct proto *p) |
| { |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| return p == &tcp_prot || p == &tcpv6_prot; |
| #else |
| return p == &tcp_prot; |
| #endif |
| } |
| |
| static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, |
| int flags, bool kern) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sock->sk); |
| struct socket *ssock; |
| int err; |
| |
| pr_debug("msk=%p", msk); |
| |
| lock_sock(sock->sk); |
| if (sock->sk->sk_state != TCP_LISTEN) |
| goto unlock_fail; |
| |
| ssock = __mptcp_nmpc_socket(msk); |
| if (!ssock) |
| goto unlock_fail; |
| |
| sock_hold(ssock->sk); |
| release_sock(sock->sk); |
| |
| err = ssock->ops->accept(sock, newsock, flags, kern); |
| if (err == 0 && !is_tcp_proto(newsock->sk->sk_prot)) { |
| struct mptcp_sock *msk = mptcp_sk(newsock->sk); |
| struct mptcp_subflow_context *subflow; |
| |
| /* set ssk->sk_socket of accept()ed flows to mptcp socket. |
| * This is needed so NOSPACE flag can be set from tcp stack. |
| */ |
| __mptcp_flush_join_list(msk); |
| list_for_each_entry(subflow, &msk->conn_list, node) { |
| struct sock *ssk = mptcp_subflow_tcp_sock(subflow); |
| |
| if (!ssk->sk_socket) |
| mptcp_sock_graft(ssk, newsock); |
| } |
| } |
| |
| sock_put(ssock->sk); |
| return err; |
| |
| unlock_fail: |
| release_sock(sock->sk); |
| return -EINVAL; |
| } |
| |
| static __poll_t mptcp_poll(struct file *file, struct socket *sock, |
| struct poll_table_struct *wait) |
| { |
| struct sock *sk = sock->sk; |
| struct mptcp_sock *msk; |
| struct socket *ssock; |
| __poll_t mask = 0; |
| |
| msk = mptcp_sk(sk); |
| lock_sock(sk); |
| ssock = __mptcp_tcp_fallback(msk); |
| if (!ssock) |
| ssock = __mptcp_nmpc_socket(msk); |
| if (ssock) { |
| mask = ssock->ops->poll(file, ssock, wait); |
| release_sock(sk); |
| return mask; |
| } |
| |
| release_sock(sk); |
| sock_poll_wait(file, sock, wait); |
| lock_sock(sk); |
| |
| if (test_bit(MPTCP_DATA_READY, &msk->flags)) |
| mask = EPOLLIN | EPOLLRDNORM; |
| if (sk_stream_is_writeable(sk) && |
| test_bit(MPTCP_SEND_SPACE, &msk->flags)) |
| mask |= EPOLLOUT | EPOLLWRNORM; |
| if (sk->sk_shutdown & RCV_SHUTDOWN) |
| mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; |
| |
| release_sock(sk); |
| |
| return mask; |
| } |
| |
| static int mptcp_shutdown(struct socket *sock, int how) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sock->sk); |
| struct mptcp_subflow_context *subflow; |
| struct socket *ssock; |
| int ret = 0; |
| |
| pr_debug("sk=%p, how=%d", msk, how); |
| |
| lock_sock(sock->sk); |
| ssock = __mptcp_tcp_fallback(msk); |
| if (ssock) { |
| release_sock(sock->sk); |
| return inet_shutdown(ssock, how); |
| } |
| |
| if (how == SHUT_WR || how == SHUT_RDWR) |
| inet_sk_state_store(sock->sk, TCP_FIN_WAIT1); |
| |
| how++; |
| |
| if ((how & ~SHUTDOWN_MASK) || !how) { |
| ret = -EINVAL; |
| goto out_unlock; |
| } |
| |
| if (sock->state == SS_CONNECTING) { |
| if ((1 << sock->sk->sk_state) & |
| (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)) |
| sock->state = SS_DISCONNECTING; |
| else |
| sock->state = SS_CONNECTED; |
| } |
| |
| __mptcp_flush_join_list(msk); |
| mptcp_for_each_subflow(msk, subflow) { |
| struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); |
| |
| mptcp_subflow_shutdown(tcp_sk, how, 1, msk->write_seq); |
| } |
| |
| out_unlock: |
| release_sock(sock->sk); |
| |
| return ret; |
| } |
| |
| static const struct proto_ops mptcp_stream_ops = { |
| .family = PF_INET, |
| .owner = THIS_MODULE, |
| .release = inet_release, |
| .bind = mptcp_bind, |
| .connect = mptcp_stream_connect, |
| .socketpair = sock_no_socketpair, |
| .accept = mptcp_stream_accept, |
| .getname = mptcp_v4_getname, |
| .poll = mptcp_poll, |
| .ioctl = inet_ioctl, |
| .gettstamp = sock_gettstamp, |
| .listen = mptcp_listen, |
| .shutdown = mptcp_shutdown, |
| .setsockopt = sock_common_setsockopt, |
| .getsockopt = sock_common_getsockopt, |
| .sendmsg = inet_sendmsg, |
| .recvmsg = inet_recvmsg, |
| .mmap = sock_no_mmap, |
| .sendpage = inet_sendpage, |
| #ifdef CONFIG_COMPAT |
| .compat_setsockopt = compat_sock_common_setsockopt, |
| .compat_getsockopt = compat_sock_common_getsockopt, |
| #endif |
| }; |
| |
| static struct inet_protosw mptcp_protosw = { |
| .type = SOCK_STREAM, |
| .protocol = IPPROTO_MPTCP, |
| .prot = &mptcp_prot, |
| .ops = &mptcp_stream_ops, |
| .flags = INET_PROTOSW_ICSK, |
| }; |
| |
| void mptcp_proto_init(void) |
| { |
| mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo; |
| |
| if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL)) |
| panic("Failed to allocate MPTCP pcpu counter\n"); |
| |
| mptcp_subflow_init(); |
| mptcp_pm_init(); |
| |
| if (proto_register(&mptcp_prot, 1) != 0) |
| panic("Failed to register MPTCP proto.\n"); |
| |
| inet_register_protosw(&mptcp_protosw); |
| |
| BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb)); |
| } |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| static const struct proto_ops mptcp_v6_stream_ops = { |
| .family = PF_INET6, |
| .owner = THIS_MODULE, |
| .release = inet6_release, |
| .bind = mptcp_bind, |
| .connect = mptcp_stream_connect, |
| .socketpair = sock_no_socketpair, |
| .accept = mptcp_stream_accept, |
| .getname = mptcp_v6_getname, |
| .poll = mptcp_poll, |
| .ioctl = inet6_ioctl, |
| .gettstamp = sock_gettstamp, |
| .listen = mptcp_listen, |
| .shutdown = mptcp_shutdown, |
| .setsockopt = sock_common_setsockopt, |
| .getsockopt = sock_common_getsockopt, |
| .sendmsg = inet6_sendmsg, |
| .recvmsg = inet6_recvmsg, |
| .mmap = sock_no_mmap, |
| .sendpage = inet_sendpage, |
| #ifdef CONFIG_COMPAT |
| .compat_setsockopt = compat_sock_common_setsockopt, |
| .compat_getsockopt = compat_sock_common_getsockopt, |
| #endif |
| }; |
| |
| static struct proto mptcp_v6_prot; |
| |
| static void mptcp_v6_destroy(struct sock *sk) |
| { |
| mptcp_destroy(sk); |
| inet6_destroy_sock(sk); |
| } |
| |
| static struct inet_protosw mptcp_v6_protosw = { |
| .type = SOCK_STREAM, |
| .protocol = IPPROTO_MPTCP, |
| .prot = &mptcp_v6_prot, |
| .ops = &mptcp_v6_stream_ops, |
| .flags = INET_PROTOSW_ICSK, |
| }; |
| |
| int mptcp_proto_v6_init(void) |
| { |
| int err; |
| |
| mptcp_v6_prot = mptcp_prot; |
| strcpy(mptcp_v6_prot.name, "MPTCPv6"); |
| mptcp_v6_prot.slab = NULL; |
| mptcp_v6_prot.destroy = mptcp_v6_destroy; |
| mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); |
| |
| err = proto_register(&mptcp_v6_prot, 1); |
| if (err) |
| return err; |
| |
| err = inet6_register_protosw(&mptcp_v6_protosw); |
| if (err) |
| proto_unregister(&mptcp_v6_prot); |
| |
| return err; |
| } |
| #endif |