diff options
Diffstat (limited to '')
| -rw-r--r-- | net/mptcp/protocol.c | 4102 |
1 files changed, 4102 insertions, 0 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c new file mode 100644 index 0000000000..5c003a0f0f --- /dev/null +++ b/net/mptcp/protocol.c @@ -0,0 +1,4102 @@ +// 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> +#include <net/tcp_states.h> +#if IS_ENABLED(CONFIG_MPTCP_IPV6) +#include <net/transp_v6.h> +#endif +#include <net/mptcp.h> +#include <net/xfrm.h> +#include <asm/ioctls.h> +#include "protocol.h" +#include "mib.h" + +#define CREATE_TRACE_POINTS +#include <trace/events/mptcp.h> + +#if IS_ENABLED(CONFIG_MPTCP_IPV6) +struct mptcp6_sock { + struct mptcp_sock msk; + struct ipv6_pinfo np; +}; +#endif + +enum { + MPTCP_CMSG_TS = BIT(0), + MPTCP_CMSG_INQ = BIT(1), +}; + +static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp; + +static void __mptcp_destroy_sock(struct sock *sk); +static void mptcp_check_send_data_fin(struct sock *sk); + +DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions); +static struct net_device mptcp_napi_dev; + +/* Returns end sequence number of the receiver's advertised window */ +static u64 mptcp_wnd_end(const struct mptcp_sock *msk) +{ + return READ_ONCE(msk->wnd_end); +} + +static bool mptcp_is_tcpsk(struct sock *sk) +{ + struct socket *sock = sk->sk_socket; + + 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. + */ + WRITE_ONCE(sock->ops, &inet_stream_ops); + return true; +#if IS_ENABLED(CONFIG_MPTCP_IPV6) + } else if (unlikely(sk->sk_prot == &tcpv6_prot)) { + WRITE_ONCE(sock->ops, &inet6_stream_ops); + return true; +#endif + } + + return false; +} + +static int __mptcp_socket_create(struct mptcp_sock *msk) +{ + struct mptcp_subflow_context *subflow; + struct sock *sk = (struct sock *)msk; + struct socket *ssock; + int err; + + err = mptcp_subflow_create_socket(sk, sk->sk_family, &ssock); + if (err) + return err; + + msk->scaling_ratio = tcp_sk(ssock->sk)->scaling_ratio; + WRITE_ONCE(msk->first, ssock->sk); + subflow = mptcp_subflow_ctx(ssock->sk); + list_add(&subflow->node, &msk->conn_list); + sock_hold(ssock->sk); + subflow->request_mptcp = 1; + subflow->subflow_id = msk->subflow_id++; + + /* This is the first subflow, always with id 0 */ + subflow->local_id_valid = 1; + mptcp_sock_graft(msk->first, sk->sk_socket); + iput(SOCK_INODE(ssock)); + + return 0; +} + +/* If the MPC handshake is not started, returns the first subflow, + * eventually allocating it. + */ +struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk) +{ + struct sock *sk = (struct sock *)msk; + int ret; + + if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) + return ERR_PTR(-EINVAL); + + if (!msk->first) { + ret = __mptcp_socket_create(msk); + if (ret) + return ERR_PTR(ret); + + mptcp_sockopt_sync(msk, msk->first); + } + + return msk->first; +} + +static void mptcp_drop(struct sock *sk, struct sk_buff *skb) +{ + sk_drops_add(sk, skb); + __kfree_skb(skb); +} + +static void mptcp_rmem_fwd_alloc_add(struct sock *sk, int size) +{ + WRITE_ONCE(mptcp_sk(sk)->rmem_fwd_alloc, + mptcp_sk(sk)->rmem_fwd_alloc + size); +} + +static void mptcp_rmem_charge(struct sock *sk, int size) +{ + mptcp_rmem_fwd_alloc_add(sk, -size); +} + +static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to, + struct sk_buff *from) +{ + bool fragstolen; + int delta; + + if (MPTCP_SKB_CB(from)->offset || + !skb_try_coalesce(to, from, &fragstolen, &delta)) + return false; + + pr_debug("colesced seq %llx into %llx new len %d new end seq %llx", + MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq, + to->len, MPTCP_SKB_CB(from)->end_seq); + MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq; + + /* note the fwd memory can reach a negative value after accounting + * for the delta, but the later skb free will restore a non + * negative one + */ + atomic_add(delta, &sk->sk_rmem_alloc); + mptcp_rmem_charge(sk, delta); + kfree_skb_partial(from, fragstolen); + + return true; +} + +static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to, + struct sk_buff *from) +{ + if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq) + return false; + + return mptcp_try_coalesce((struct sock *)msk, to, from); +} + +static void __mptcp_rmem_reclaim(struct sock *sk, int amount) +{ + amount >>= PAGE_SHIFT; + mptcp_rmem_charge(sk, amount << PAGE_SHIFT); + __sk_mem_reduce_allocated(sk, amount); +} + +static void mptcp_rmem_uncharge(struct sock *sk, int size) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + int reclaimable; + + mptcp_rmem_fwd_alloc_add(sk, size); + reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk); + + /* see sk_mem_uncharge() for the rationale behind the following schema */ + if (unlikely(reclaimable >= PAGE_SIZE)) + __mptcp_rmem_reclaim(sk, reclaimable); +} + +static void mptcp_rfree(struct sk_buff *skb) +{ + unsigned int len = skb->truesize; + struct sock *sk = skb->sk; + + atomic_sub(len, &sk->sk_rmem_alloc); + mptcp_rmem_uncharge(sk, len); +} + +void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk) +{ + skb_orphan(skb); + skb->sk = sk; + skb->destructor = mptcp_rfree; + atomic_add(skb->truesize, &sk->sk_rmem_alloc); + mptcp_rmem_charge(sk, skb->truesize); +} + +/* "inspired" by tcp_data_queue_ofo(), main differences: + * - use mptcp seqs + * - don't cope with sacks + */ +static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb) +{ + struct sock *sk = (struct sock *)msk; + struct rb_node **p, *parent; + u64 seq, end_seq, max_seq; + struct sk_buff *skb1; + + seq = MPTCP_SKB_CB(skb)->map_seq; + end_seq = MPTCP_SKB_CB(skb)->end_seq; + max_seq = atomic64_read(&msk->rcv_wnd_sent); + + pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq, + RB_EMPTY_ROOT(&msk->out_of_order_queue)); + if (after64(end_seq, max_seq)) { + /* out of window */ + mptcp_drop(sk, skb); + pr_debug("oow by %lld, rcv_wnd_sent %llu\n", + (unsigned long long)end_seq - (unsigned long)max_seq, + (unsigned long long)atomic64_read(&msk->rcv_wnd_sent)); + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW); + return; + } + + p = &msk->out_of_order_queue.rb_node; + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE); + if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) { + rb_link_node(&skb->rbnode, NULL, p); + rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); + msk->ooo_last_skb = skb; + goto end; + } + + /* with 2 subflows, adding at end of ooo queue is quite likely + * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup. + */ + if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) { + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); + return; + } + + /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */ + if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) { + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); + parent = &msk->ooo_last_skb->rbnode; + p = &parent->rb_right; + goto insert; + } + + /* Find place to insert this segment. Handle overlaps on the way. */ + parent = NULL; + while (*p) { + parent = *p; + skb1 = rb_to_skb(parent); + if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { + p = &parent->rb_left; + continue; + } + if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) { + if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) { + /* All the bits are present. Drop. */ + mptcp_drop(sk, skb); + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); + return; + } + if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { + /* partial overlap: + * | skb | + * | skb1 | + * continue traversing + */ + } else { + /* skb's seq == skb1's seq and skb covers skb1. + * Replace skb1 with skb. + */ + rb_replace_node(&skb1->rbnode, &skb->rbnode, + &msk->out_of_order_queue); + mptcp_drop(sk, skb1); + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); + goto merge_right; + } + } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) { + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); + return; + } + p = &parent->rb_right; + } + +insert: + /* Insert segment into RB tree. */ + rb_link_node(&skb->rbnode, parent, p); + rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); + +merge_right: + /* Remove other segments covered by skb. */ + while ((skb1 = skb_rb_next(skb)) != NULL) { + if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) + break; + rb_erase(&skb1->rbnode, &msk->out_of_order_queue); + mptcp_drop(sk, skb1); + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); + } + /* If there is no skb after us, we are the last_skb ! */ + if (!skb1) + msk->ooo_last_skb = skb; + +end: + skb_condense(skb); + mptcp_set_owner_r(skb, sk); +} + +static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + int amt, amount; + + if (size <= msk->rmem_fwd_alloc) + return true; + + size -= msk->rmem_fwd_alloc; + amt = sk_mem_pages(size); + amount = amt << PAGE_SHIFT; + if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV)) + return false; + + mptcp_rmem_fwd_alloc_add(sk, amount); + return true; +} + +static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, + struct sk_buff *skb, unsigned int offset, + size_t copy_len) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + struct sock *sk = (struct sock *)msk; + struct sk_buff *tail; + bool has_rxtstamp; + + __skb_unlink(skb, &ssk->sk_receive_queue); + + skb_ext_reset(skb); + skb_orphan(skb); + + /* try to fetch required memory from subflow */ + if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) + goto drop; + + has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp; + + /* the skb map_seq accounts for the skb offset: + * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq + * value + */ + MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow); + MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len; + MPTCP_SKB_CB(skb)->offset = offset; + MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp; + + if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) { + /* in sequence */ + msk->bytes_received += copy_len; + WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len); + tail = skb_peek_tail(&sk->sk_receive_queue); + if (tail && mptcp_try_coalesce(sk, tail, skb)) + return true; + + mptcp_set_owner_r(skb, sk); + __skb_queue_tail(&sk->sk_receive_queue, skb); + return true; + } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) { + mptcp_data_queue_ofo(msk, skb); + return false; + } + + /* old data, keep it simple and drop the whole pkt, sender + * will retransmit as needed, if needed. + */ + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); +drop: + mptcp_drop(sk, skb); + return false; +} + +static void mptcp_stop_rtx_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 void mptcp_close_wake_up(struct sock *sk) +{ + if (sock_flag(sk, SOCK_DEAD)) + return; + + sk->sk_state_change(sk); + if (sk->sk_shutdown == SHUTDOWN_MASK || + sk->sk_state == TCP_CLOSE) + sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); + else + sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); +} + +static bool mptcp_pending_data_fin_ack(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + return ((1 << sk->sk_state) & + (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) && + msk->write_seq == READ_ONCE(msk->snd_una); +} + +static void mptcp_check_data_fin_ack(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + /* Look for an acknowledged DATA_FIN */ + if (mptcp_pending_data_fin_ack(sk)) { + WRITE_ONCE(msk->snd_data_fin_enable, 0); + + switch (sk->sk_state) { + case TCP_FIN_WAIT1: + inet_sk_state_store(sk, TCP_FIN_WAIT2); + break; + case TCP_CLOSING: + case TCP_LAST_ACK: + inet_sk_state_store(sk, TCP_CLOSE); + break; + } + + mptcp_close_wake_up(sk); + } +} + +static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + if (READ_ONCE(msk->rcv_data_fin) && + ((1 << sk->sk_state) & + (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) { + u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq); + + if (msk->ack_seq == rcv_data_fin_seq) { + if (seq) + *seq = rcv_data_fin_seq; + + return true; + } + } + + return false; +} + +static void mptcp_set_datafin_timeout(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + u32 retransmits; + + retransmits = min_t(u32, icsk->icsk_retransmits, + ilog2(TCP_RTO_MAX / TCP_RTO_MIN)); + + mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits; +} + +static void __mptcp_set_timeout(struct sock *sk, long tout) +{ + mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; +} + +static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow) +{ + const struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + + return inet_csk(ssk)->icsk_pending && !subflow->stale_count ? + inet_csk(ssk)->icsk_timeout - jiffies : 0; +} + +static void mptcp_set_timeout(struct sock *sk) +{ + struct mptcp_subflow_context *subflow; + long tout = 0; + + mptcp_for_each_subflow(mptcp_sk(sk), subflow) + tout = max(tout, mptcp_timeout_from_subflow(subflow)); + __mptcp_set_timeout(sk, tout); +} + +static inline bool tcp_can_send_ack(const struct sock *ssk) +{ + return !((1 << inet_sk_state_load(ssk)) & + (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN)); +} + +void __mptcp_subflow_send_ack(struct sock *ssk) +{ + if (tcp_can_send_ack(ssk)) + tcp_send_ack(ssk); +} + +static void mptcp_subflow_send_ack(struct sock *ssk) +{ + bool slow; + + slow = lock_sock_fast(ssk); + __mptcp_subflow_send_ack(ssk); + unlock_sock_fast(ssk, slow); +} + +static void mptcp_send_ack(struct mptcp_sock *msk) +{ + struct mptcp_subflow_context *subflow; + + mptcp_for_each_subflow(msk, subflow) + mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow)); +} + +static void mptcp_subflow_cleanup_rbuf(struct sock *ssk) +{ + bool slow; + + slow = lock_sock_fast(ssk); + if (tcp_can_send_ack(ssk)) + tcp_cleanup_rbuf(ssk, 1); + unlock_sock_fast(ssk, slow); +} + +static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty) +{ + const struct inet_connection_sock *icsk = inet_csk(ssk); + u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending); + const struct tcp_sock *tp = tcp_sk(ssk); + + return (ack_pending & ICSK_ACK_SCHED) && + ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) > + READ_ONCE(icsk->icsk_ack.rcv_mss)) || + (rx_empty && ack_pending & + (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED))); +} + +static void mptcp_cleanup_rbuf(struct mptcp_sock *msk) +{ + int old_space = READ_ONCE(msk->old_wspace); + struct mptcp_subflow_context *subflow; + struct sock *sk = (struct sock *)msk; + int space = __mptcp_space(sk); + bool cleanup, rx_empty; + + cleanup = (space > 0) && (space >= (old_space << 1)); + rx_empty = !__mptcp_rmem(sk); + + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + + if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty)) + mptcp_subflow_cleanup_rbuf(ssk); + } +} + +static bool mptcp_check_data_fin(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + u64 rcv_data_fin_seq; + bool ret = false; + + /* Need to ack a DATA_FIN received from a peer while this side + * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. + * msk->rcv_data_fin was set when parsing the incoming options + * at the subflow level and the msk lock was not held, so this + * is the first opportunity to act on the DATA_FIN and change + * the msk state. + * + * If we are caught up to the sequence number of the incoming + * DATA_FIN, send the DATA_ACK now and do state transition. If + * not caught up, do nothing and let the recv code send DATA_ACK + * when catching up. + */ + + if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) { + WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1); + WRITE_ONCE(msk->rcv_data_fin, 0); + + WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN); + smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ + + switch (sk->sk_state) { + case TCP_ESTABLISHED: + inet_sk_state_store(sk, TCP_CLOSE_WAIT); + break; + case TCP_FIN_WAIT1: + inet_sk_state_store(sk, TCP_CLOSING); + break; + case TCP_FIN_WAIT2: + inet_sk_state_store(sk, TCP_CLOSE); + break; + default: + /* Other states not expected */ + WARN_ON_ONCE(1); + break; + } + + ret = true; + if (!__mptcp_check_fallback(msk)) + mptcp_send_ack(msk); + mptcp_close_wake_up(sk); + } + return ret; +} + +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; + int sk_rbuf; + + sk_rbuf = READ_ONCE(sk->sk_rcvbuf); + + if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { + int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); + + if (unlikely(ssk_rbuf > sk_rbuf)) { + WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf); + sk_rbuf = ssk_rbuf; + } + } + + pr_debug("msk=%p ssk=%p", msk, ssk); + 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) { + /* With racing move_skbs_to_msk() and __mptcp_move_skbs(), + * a different CPU can have already processed the pending + * data, stop here or we can enter an infinite loop + */ + if (!moved) + done = true; + break; + } + + if (__mptcp_check_fallback(msk)) { + /* Under fallback skbs have no MPTCP extension and TCP could + * collapse them between the dummy map creation and the + * current dequeue. Be sure to adjust the map size. + */ + map_remaining = skb->len; + subflow->map_data_len = skb->len; + } + + 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; + + if (__mptcp_move_skb(msk, ssk, skb, offset, len)) + moved += len; + seq += 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) > sk_rbuf) { + done = true; + break; + } + } while (more_data_avail); + + *bytes += moved; + return done; +} + +static bool __mptcp_ofo_queue(struct mptcp_sock *msk) +{ + struct sock *sk = (struct sock *)msk; + struct sk_buff *skb, *tail; + bool moved = false; + struct rb_node *p; + u64 end_seq; + + p = rb_first(&msk->out_of_order_queue); + pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue)); + while (p) { + skb = rb_to_skb(p); + if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) + break; + + p = rb_next(p); + rb_erase(&skb->rbnode, &msk->out_of_order_queue); + + if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq, + msk->ack_seq))) { + mptcp_drop(sk, skb); + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); + continue; + } + + end_seq = MPTCP_SKB_CB(skb)->end_seq; + tail = skb_peek_tail(&sk->sk_receive_queue); + if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) { + int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; + + /* skip overlapping data, if any */ + pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d", + MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq, + delta); + MPTCP_SKB_CB(skb)->offset += delta; + MPTCP_SKB_CB(skb)->map_seq += delta; + __skb_queue_tail(&sk->sk_receive_queue, skb); + } + msk->bytes_received += end_seq - msk->ack_seq; + msk->ack_seq = end_seq; + moved = true; + } + return moved; +} + +static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk) +{ + int err = sock_error(ssk); + int ssk_state; + + if (!err) + return false; + + /* only propagate errors on fallen-back sockets or + * on MPC connect + */ + if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk))) + return false; + + /* We need to propagate only transition to CLOSE state. + * Orphaned socket will see such state change via + * subflow_sched_work_if_closed() and that path will properly + * destroy the msk as needed. + */ + ssk_state = inet_sk_state_load(ssk); + if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD)) + inet_sk_state_store(sk, ssk_state); + WRITE_ONCE(sk->sk_err, -err); + + /* This barrier is coupled with smp_rmb() in mptcp_poll() */ + smp_wmb(); + sk_error_report(sk); + return true; +} + +void __mptcp_error_report(struct sock *sk) +{ + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk = mptcp_sk(sk); + + mptcp_for_each_subflow(msk, subflow) + if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow))) + break; +} + +/* 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; + + __mptcp_move_skbs_from_subflow(msk, ssk, &moved); + __mptcp_ofo_queue(msk); + if (unlikely(ssk->sk_err)) { + if (!sock_owned_by_user(sk)) + __mptcp_error_report(sk); + else + __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags); + } + + /* If the moves have caught up with the DATA_FIN sequence number + * it's time to ack the DATA_FIN and change socket state, but + * this is not a good place to change state. Let the workqueue + * do it. + */ + if (mptcp_pending_data_fin(sk, NULL)) + mptcp_schedule_work(sk); + return moved > 0; +} + +void mptcp_data_ready(struct sock *sk, struct sock *ssk) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + struct mptcp_sock *msk = mptcp_sk(sk); + int sk_rbuf, ssk_rbuf; + + /* The peer can send data while we are shutting down this + * subflow at msk destruction time, but we must avoid enqueuing + * more data to the msk receive queue + */ + if (unlikely(subflow->disposable)) + return; + + ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); + sk_rbuf = READ_ONCE(sk->sk_rcvbuf); + if (unlikely(ssk_rbuf > sk_rbuf)) + sk_rbuf = ssk_rbuf; + + /* over limit? can't append more skbs to msk, Also, no need to wake-up*/ + if (__mptcp_rmem(sk) > sk_rbuf) { + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); + return; + } + + /* Wake-up the reader only for in-sequence data */ + mptcp_data_lock(sk); + if (move_skbs_to_msk(msk, ssk)) + sk->sk_data_ready(sk); + + mptcp_data_unlock(sk); +} + +static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk) +{ + mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq); + WRITE_ONCE(msk->allow_infinite_fallback, false); + mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); +} + +static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk) +{ + struct sock *sk = (struct sock *)msk; + + if (sk->sk_state != TCP_ESTABLISHED) + return false; + + /* attach to msk socket only after we are sure we will deal with it + * at close time + */ + if (sk->sk_socket && !ssk->sk_socket) + mptcp_sock_graft(ssk, sk->sk_socket); + + mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++; + mptcp_sockopt_sync_locked(msk, ssk); + mptcp_subflow_joined(msk, ssk); + mptcp_stop_tout_timer(sk); + __mptcp_propagate_sndbuf(sk, ssk); + return true; +} + +static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list) +{ + struct mptcp_subflow_context *tmp, *subflow; + struct mptcp_sock *msk = mptcp_sk(sk); + + list_for_each_entry_safe(subflow, tmp, join_list, node) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + bool slow = lock_sock_fast(ssk); + + list_move_tail(&subflow->node, &msk->conn_list); + if (!__mptcp_finish_join(msk, ssk)) + mptcp_subflow_reset(ssk); + unlock_sock_fast(ssk, slow); + } +} + +static bool mptcp_rtx_timer_pending(struct sock *sk) +{ + return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); +} + +static void mptcp_reset_rtx_timer(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + unsigned long tout; + + /* prevent rescheduling on close */ + if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE)) + return; + + tout = mptcp_sk(sk)->timer_ival; + sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout); +} + +bool mptcp_schedule_work(struct sock *sk) +{ + if (inet_sk_state_load(sk) != TCP_CLOSE && + schedule_work(&mptcp_sk(sk)->work)) { + /* each subflow already holds a reference to the sk, and the + * workqueue is invoked by a subflow, so sk can't go away here. + */ + sock_hold(sk); + return true; + } + return false; +} + +static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk) +{ + struct mptcp_subflow_context *subflow; + + msk_owned_by_me(msk); + + mptcp_for_each_subflow(msk, subflow) { + if (READ_ONCE(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 and this + * mapping has not been xmitted yet + */ + return mpext && mpext->data_seq + mpext->data_len == write_seq && + !mpext->frozen; +} + +/* we can append data to the given data frag if: + * - there is space available in the backing page_frag + * - the data frag tail matches the current page_frag free offset + * - the data frag end sequence number matches the current 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 && + pfrag->size - pfrag->offset > 0 && + pfrag->offset == (df->offset + df->data_len) && + 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; + + snd_una = msk->snd_una; + list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { + if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) + break; + + if (unlikely(dfrag == msk->first_pending)) { + /* in recovery mode can see ack after the current snd head */ + if (WARN_ON_ONCE(!msk->recovery)) + break; + + WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); + } + + dfrag_clear(sk, dfrag); + } + + dfrag = mptcp_rtx_head(sk); + if (dfrag && after64(snd_una, dfrag->data_seq)) { + u64 delta = snd_una - dfrag->data_seq; + + /* prevent wrap around in recovery mode */ + if (unlikely(delta > dfrag->already_sent)) { + if (WARN_ON_ONCE(!msk->recovery)) + goto out; + if (WARN_ON_ONCE(delta > dfrag->data_len)) + goto out; + dfrag->already_sent += delta - dfrag->already_sent; + } + + dfrag->data_seq += delta; + dfrag->offset += delta; + dfrag->data_len -= delta; + dfrag->already_sent -= delta; + + dfrag_uncharge(sk, delta); + } + + /* all retransmitted data acked, recovery completed */ + if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt)) + msk->recovery = false; + +out: + if (snd_una == READ_ONCE(msk->snd_nxt) && + snd_una == READ_ONCE(msk->write_seq)) { + if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk)) + mptcp_stop_rtx_timer(sk); + } else { + mptcp_reset_rtx_timer(sk); + } +} + +static void __mptcp_clean_una_wakeup(struct sock *sk) +{ + lockdep_assert_held_once(&sk->sk_lock.slock); + + __mptcp_clean_una(sk); + mptcp_write_space(sk); +} + +static void mptcp_clean_una_wakeup(struct sock *sk) +{ + mptcp_data_lock(sk); + __mptcp_clean_una_wakeup(sk); + mptcp_data_unlock(sk); +} + +static void mptcp_enter_memory_pressure(struct sock *sk) +{ + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk = mptcp_sk(sk); + bool first = true; + + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + + if (first) + tcp_enter_memory_pressure(ssk); + sk_stream_moderate_sndbuf(ssk); + + first = false; + } + __mptcp_sync_sndbuf(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; + + mptcp_enter_memory_pressure(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->already_sent = 0; + dfrag->page = pfrag->page; + + return dfrag; +} + +struct mptcp_sendmsg_info { + int mss_now; + int size_goal; + u16 limit; + u16 sent; + unsigned int flags; + bool data_lock_held; +}; + +static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk, + u64 data_seq, int avail_size) +{ + u64 window_end = mptcp_wnd_end(msk); + u64 mptcp_snd_wnd; + + if (__mptcp_check_fallback(msk)) + return avail_size; + + mptcp_snd_wnd = window_end - data_seq; + avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size); + + if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) { + tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd); + MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED); + } + + return avail_size; +} + +static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp) +{ + struct skb_ext *mpext = __skb_ext_alloc(gfp); + + if (!mpext) + return false; + __skb_ext_set(skb, SKB_EXT_MPTCP, mpext); + return true; +} + +static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp) +{ + struct sk_buff *skb; + + skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp); + if (likely(skb)) { + if (likely(__mptcp_add_ext(skb, gfp))) { + skb_reserve(skb, MAX_TCP_HEADER); + skb->ip_summed = CHECKSUM_PARTIAL; + INIT_LIST_HEAD(&skb->tcp_tsorted_anchor); + return skb; + } + __kfree_skb(skb); + } else { + mptcp_enter_memory_pressure(sk); + } + return NULL; +} + +static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp) +{ + struct sk_buff *skb; + + skb = __mptcp_do_alloc_tx_skb(sk, gfp); + if (!skb) + return NULL; + + if (likely(sk_wmem_schedule(ssk, skb->truesize))) { + tcp_skb_entail(ssk, skb); + return skb; + } + tcp_skb_tsorted_anchor_cleanup(skb); + kfree_skb(skb); + return NULL; +} + +static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held) +{ + gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation; + + return __mptcp_alloc_tx_skb(sk, ssk, gfp); +} + +/* note: this always recompute the csum on the whole skb, even + * if we just appended a single frag. More status info needed + */ +static void mptcp_update_data_checksum(struct sk_buff *skb, int added) +{ + struct mptcp_ext *mpext = mptcp_get_ext(skb); + __wsum csum = ~csum_unfold(mpext->csum); + int offset = skb->len - added; + + mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset)); +} + +static void mptcp_update_infinite_map(struct mptcp_sock *msk, + struct sock *ssk, + struct mptcp_ext *mpext) +{ + if (!mpext) + return; + + mpext->infinite_map = 1; + mpext->data_len = 0; + + MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX); + mptcp_subflow_ctx(ssk)->send_infinite_map = 0; + pr_fallback(msk); + mptcp_do_fallback(ssk); +} + +#define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1)) + +static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, + struct mptcp_data_frag *dfrag, + struct mptcp_sendmsg_info *info) +{ + u64 data_seq = dfrag->data_seq + info->sent; + int offset = dfrag->offset + info->sent; + struct mptcp_sock *msk = mptcp_sk(sk); + bool zero_window_probe = false; + struct mptcp_ext *mpext = NULL; + bool can_coalesce = false; + bool reuse_skb = true; + struct sk_buff *skb; + size_t copy; + int i; + + pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u", + msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent); + + if (WARN_ON_ONCE(info->sent > info->limit || + info->limit > dfrag->data_len)) + return 0; + + if (unlikely(!__tcp_can_send(ssk))) + return -EAGAIN; + + /* compute send limit */ + if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE)) + ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE; + info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags); + copy = info->size_goal; + + skb = tcp_write_queue_tail(ssk); + if (skb && copy > skb->len) { + /* 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 + */ + mpext = skb_ext_find(skb, SKB_EXT_MPTCP); + if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) { + TCP_SKB_CB(skb)->eor = 1; + goto alloc_skb; + } + + i = skb_shinfo(skb)->nr_frags; + can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset); + if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) { + tcp_mark_push(tcp_sk(ssk), skb); + goto alloc_skb; + } + + copy -= skb->len; + } else { +alloc_skb: + skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held); + if (!skb) + return -ENOMEM; + + i = skb_shinfo(skb)->nr_frags; + reuse_skb = false; + mpext = skb_ext_find(skb, SKB_EXT_MPTCP); + } + + /* Zero window and all data acked? Probe. */ + copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy); + if (copy == 0) { + u64 snd_una = READ_ONCE(msk->snd_una); + + if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) { + tcp_remove_empty_skb(ssk); + return 0; + } + + zero_window_probe = true; + data_seq = snd_una - 1; + copy = 1; + } + + copy = min_t(size_t, copy, info->limit - info->sent); + if (!sk_wmem_schedule(ssk, copy)) { + tcp_remove_empty_skb(ssk); + return -ENOMEM; + } + + if (can_coalesce) { + skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); + } else { + get_page(dfrag->page); + skb_fill_page_desc(skb, i, dfrag->page, offset, copy); + } + + skb->len += copy; + skb->data_len += copy; + skb->truesize += copy; + sk_wmem_queued_add(ssk, copy); + sk_mem_charge(ssk, copy); + WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy); + TCP_SKB_CB(skb)->end_seq += copy; + tcp_skb_pcount_set(skb, 0); + + /* on skb reuse we just need to update the DSS len */ + if (reuse_skb) { + TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; + mpext->data_len += copy; + goto out; + } + + memset(mpext, 0, sizeof(*mpext)); + mpext->data_seq = data_seq; + mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq; + mpext->data_len = copy; + 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); + + if (zero_window_probe) { + mptcp_subflow_ctx(ssk)->rel_write_seq += copy; + mpext->frozen = 1; + if (READ_ONCE(msk->csum_enabled)) + mptcp_update_data_checksum(skb, copy); + tcp_push_pending_frames(ssk); + return 0; + } +out: + if (READ_ONCE(msk->csum_enabled)) + mptcp_update_data_checksum(skb, copy); + if (mptcp_subflow_ctx(ssk)->send_infinite_map) + mptcp_update_infinite_map(msk, ssk, mpext); + trace_mptcp_sendmsg_frag(mpext); + mptcp_subflow_ctx(ssk)->rel_write_seq += copy; + return copy; +} + +#define MPTCP_SEND_BURST_SIZE ((1 << 16) - \ + sizeof(struct tcphdr) - \ + MAX_TCP_OPTION_SPACE - \ + sizeof(struct ipv6hdr) - \ + sizeof(struct frag_hdr)) + +struct subflow_send_info { + struct sock *ssk; + u64 linger_time; +}; + +void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow) +{ + if (!subflow->stale) + return; + + subflow->stale = 0; + MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER); +} + +bool mptcp_subflow_active(struct mptcp_subflow_context *subflow) +{ + if (unlikely(subflow->stale)) { + u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp); + + if (subflow->stale_rcv_tstamp == rcv_tstamp) + return false; + + mptcp_subflow_set_active(subflow); + } + return __mptcp_subflow_active(subflow); +} + +#define SSK_MODE_ACTIVE 0 +#define SSK_MODE_BACKUP 1 +#define SSK_MODE_MAX 2 + +/* implement the mptcp packet scheduler; + * returns the subflow that will transmit the next DSS + * additionally updates the rtx timeout + */ +struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) +{ + struct subflow_send_info send_info[SSK_MODE_MAX]; + struct mptcp_subflow_context *subflow; + struct sock *sk = (struct sock *)msk; + u32 pace, burst, wmem; + int i, nr_active = 0; + struct sock *ssk; + u64 linger_time; + long tout = 0; + + /* pick the subflow with the lower wmem/wspace ratio */ + for (i = 0; i < SSK_MODE_MAX; ++i) { + send_info[i].ssk = NULL; + send_info[i].linger_time = -1; + } + + mptcp_for_each_subflow(msk, subflow) { + trace_mptcp_subflow_get_send(subflow); + ssk = mptcp_subflow_tcp_sock(subflow); + if (!mptcp_subflow_active(subflow)) + continue; + + tout = max(tout, mptcp_timeout_from_subflow(subflow)); + nr_active += !subflow->backup; + pace = subflow->avg_pacing_rate; + if (unlikely(!pace)) { + /* init pacing rate from socket */ + subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate); + pace = subflow->avg_pacing_rate; + if (!pace) + continue; + } + + linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace); + if (linger_time < send_info[subflow->backup].linger_time) { + send_info[subflow->backup].ssk = ssk; + send_info[subflow->backup].linger_time = linger_time; + } + } + __mptcp_set_timeout(sk, tout); + + /* pick the best backup if no other subflow is active */ + if (!nr_active) + send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk; + + /* According to the blest algorithm, to avoid HoL blocking for the + * faster flow, we need to: + * - estimate the faster flow linger time + * - use the above to estimate the amount of byte transferred + * by the faster flow + * - check that the amount of queued data is greter than the above, + * otherwise do not use the picked, slower, subflow + * We select the subflow with the shorter estimated time to flush + * the queued mem, which basically ensure the above. We just need + * to check that subflow has a non empty cwin. + */ + ssk = send_info[SSK_MODE_ACTIVE].ssk; + if (!ssk || !sk_stream_memory_free(ssk)) + return NULL; + + burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt); + wmem = READ_ONCE(ssk->sk_wmem_queued); + if (!burst) + return ssk; + + subflow = mptcp_subflow_ctx(ssk); + subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem + + READ_ONCE(ssk->sk_pacing_rate) * burst, + burst + wmem); + msk->snd_burst = burst; + return ssk; +} + +static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info) +{ + tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); + release_sock(ssk); +} + +static void mptcp_update_post_push(struct mptcp_sock *msk, + struct mptcp_data_frag *dfrag, + u32 sent) +{ + u64 snd_nxt_new = dfrag->data_seq; + + dfrag->already_sent += sent; + + msk->snd_burst -= sent; + + snd_nxt_new += dfrag->already_sent; + + /* snd_nxt_new can be smaller than snd_nxt in case mptcp + * is recovering after a failover. In that event, this re-sends + * old segments. + * + * Thus compute snd_nxt_new candidate based on + * the dfrag->data_seq that was sent and the data + * that has been handed to the subflow for transmission + * and skip update in case it was old dfrag. + */ + if (likely(after64(snd_nxt_new, msk->snd_nxt))) { + msk->bytes_sent += snd_nxt_new - msk->snd_nxt; + msk->snd_nxt = snd_nxt_new; + } +} + +void mptcp_check_and_set_pending(struct sock *sk) +{ + if (mptcp_send_head(sk)) + mptcp_sk(sk)->push_pending |= BIT(MPTCP_PUSH_PENDING); +} + +static int __subflow_push_pending(struct sock *sk, struct sock *ssk, + struct mptcp_sendmsg_info *info) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + struct mptcp_data_frag *dfrag; + int len, copied = 0, err = 0; + + while ((dfrag = mptcp_send_head(sk))) { + info->sent = dfrag->already_sent; + info->limit = dfrag->data_len; + len = dfrag->data_len - dfrag->already_sent; + while (len > 0) { + int ret = 0; + + ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info); + if (ret <= 0) { + err = copied ? : ret; + goto out; + } + + info->sent += ret; + copied += ret; + len -= ret; + + mptcp_update_post_push(msk, dfrag, ret); + } + WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); + + if (msk->snd_burst <= 0 || + !sk_stream_memory_free(ssk) || + !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) { + err = copied; + goto out; + } + mptcp_set_timeout(sk); + } + err = copied; + +out: + return err; +} + +void __mptcp_push_pending(struct sock *sk, unsigned int flags) +{ + struct sock *prev_ssk = NULL, *ssk = NULL; + struct mptcp_sock *msk = mptcp_sk(sk); + struct mptcp_sendmsg_info info = { + .flags = flags, + }; + bool do_check_data_fin = false; + int push_count = 1; + + while (mptcp_send_head(sk) && (push_count > 0)) { + struct mptcp_subflow_context *subflow; + int ret = 0; + + if (mptcp_sched_get_send(msk)) + break; + + push_count = 0; + + mptcp_for_each_subflow(msk, subflow) { + if (READ_ONCE(subflow->scheduled)) { + mptcp_subflow_set_scheduled(subflow, false); + + prev_ssk = ssk; + ssk = mptcp_subflow_tcp_sock(subflow); + if (ssk != prev_ssk) { + /* First check. If the ssk has changed since + * the last round, release prev_ssk + */ + if (prev_ssk) + mptcp_push_release(prev_ssk, &info); + + /* Need to lock the new subflow only if different + * from the previous one, otherwise we are still + * helding the relevant lock + */ + lock_sock(ssk); + } + + push_count++; + + ret = __subflow_push_pending(sk, ssk, &info); + if (ret <= 0) { + if (ret != -EAGAIN || + (1 << ssk->sk_state) & + (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSE)) + push_count--; + continue; + } + do_check_data_fin = true; + } + } + } + + /* at this point we held the socket lock for the last subflow we used */ + if (ssk) + mptcp_push_release(ssk, &info); + + /* ensure the rtx timer is running */ + if (!mptcp_rtx_timer_pending(sk)) + mptcp_reset_rtx_timer(sk); + if (do_check_data_fin) + mptcp_check_send_data_fin(sk); +} + +static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + struct mptcp_sendmsg_info info = { + .data_lock_held = true, + }; + bool keep_pushing = true; + struct sock *xmit_ssk; + int copied = 0; + + info.flags = 0; + while (mptcp_send_head(sk) && keep_pushing) { + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + int ret = 0; + + /* check for a different subflow usage only after + * spooling the first chunk of data + */ + if (first) { + mptcp_subflow_set_scheduled(subflow, false); + ret = __subflow_push_pending(sk, ssk, &info); + first = false; + if (ret <= 0) + break; + copied += ret; + continue; + } + + if (mptcp_sched_get_send(msk)) + goto out; + + if (READ_ONCE(subflow->scheduled)) { + mptcp_subflow_set_scheduled(subflow, false); + ret = __subflow_push_pending(sk, ssk, &info); + if (ret <= 0) + keep_pushing = false; + copied += ret; + } + + mptcp_for_each_subflow(msk, subflow) { + if (READ_ONCE(subflow->scheduled)) { + xmit_ssk = mptcp_subflow_tcp_sock(subflow); + if (xmit_ssk != ssk) { + mptcp_subflow_delegate(subflow, + MPTCP_DELEGATE_SEND); + keep_pushing = false; + } + } + } + } + +out: + /* __mptcp_alloc_tx_skb could have released some wmem and we are + * not going to flush it via release_sock() + */ + if (copied) { + tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, + info.size_goal); + if (!mptcp_rtx_timer_pending(sk)) + mptcp_reset_rtx_timer(sk); + + if (msk->snd_data_fin_enable && + msk->snd_nxt + 1 == msk->write_seq) + mptcp_schedule_work(sk); + } +} + +static void mptcp_set_nospace(struct sock *sk) +{ + /* enable autotune */ + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); + + /* will be cleared on avail space */ + set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags); +} + +static int mptcp_disconnect(struct sock *sk, int flags); + +static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, + size_t len, int *copied_syn) +{ + unsigned int saved_flags = msg->msg_flags; + struct mptcp_sock *msk = mptcp_sk(sk); + struct sock *ssk; + int ret; + + /* on flags based fastopen the mptcp is supposed to create the + * first subflow right now. Otherwise we are in the defer_connect + * path, and the first subflow must be already present. + * Since the defer_connect flag is cleared after the first succsful + * fastopen attempt, no need to check for additional subflow status. + */ + if (msg->msg_flags & MSG_FASTOPEN) { + ssk = __mptcp_nmpc_sk(msk); + if (IS_ERR(ssk)) + return PTR_ERR(ssk); + } + if (!msk->first) + return -EINVAL; + + ssk = msk->first; + + lock_sock(ssk); + msg->msg_flags |= MSG_DONTWAIT; + msk->fastopening = 1; + ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL); + msk->fastopening = 0; + msg->msg_flags = saved_flags; + release_sock(ssk); + + /* do the blocking bits of inet_stream_connect outside the ssk socket lock */ + if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) { + ret = __inet_stream_connect(sk->sk_socket, msg->msg_name, + msg->msg_namelen, msg->msg_flags, 1); + + /* Keep the same behaviour of plain TCP: zero the copied bytes in + * case of any error, except timeout or signal + */ + if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR) + *copied_syn = 0; + } else if (ret && ret != -EINPROGRESS) { + /* The disconnect() op called by tcp_sendmsg_fastopen()/ + * __inet_stream_connect() can fail, due to looking check, + * see mptcp_disconnect(). + * Attempt it again outside the problematic scope. + */ + if (!mptcp_disconnect(sk, 0)) + sk->sk_socket->state = SS_UNCONNECTED; + } + inet_clear_bit(DEFER_CONNECT, sk); + + return ret; +} + +static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + struct page_frag *pfrag; + size_t copied = 0; + int ret = 0; + long timeo; + + /* silently ignore everything else */ + msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN; + + lock_sock(sk); + + if (unlikely(inet_test_bit(DEFER_CONNECT, sk) || + msg->msg_flags & MSG_FASTOPEN)) { + int copied_syn = 0; + + ret = mptcp_sendmsg_fastopen(sk, msg, len, &copied_syn); + copied += copied_syn; + if (ret == -EINPROGRESS && copied_syn > 0) + goto out; + else if (ret) + goto do_error; + } + + 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 do_error; + } + + ret = -EPIPE; + if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))) + goto do_error; + + pfrag = sk_page_frag(sk); + + while (msg_data_left(msg)) { + int total_ts, frag_truesize = 0; + struct mptcp_data_frag *dfrag; + bool dfrag_collapsed; + size_t psize, offset; + + /* reuse tail pfrag, if possible, or carve a new one from the + * page allocator + */ + dfrag = mptcp_pending_tail(sk); + dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag); + if (!dfrag_collapsed) { + if (!sk_stream_memory_free(sk)) + goto wait_for_memory; + + if (!mptcp_page_frag_refill(sk, pfrag)) + goto wait_for_memory; + + dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset); + frag_truesize = dfrag->overhead; + } + + /* we do not bound vs wspace, to allow a single packet. + * memory accounting will prevent execessive memory usage + * anyway + */ + offset = dfrag->offset + dfrag->data_len; + psize = pfrag->size - offset; + psize = min_t(size_t, psize, msg_data_left(msg)); + total_ts = psize + frag_truesize; + + if (!sk_wmem_schedule(sk, total_ts)) + goto wait_for_memory; + + if (copy_page_from_iter(dfrag->page, offset, psize, + &msg->msg_iter) != psize) { + ret = -EFAULT; + goto do_error; + } + + /* data successfully copied into the write queue */ + sk_forward_alloc_add(sk, -total_ts); + copied += psize; + dfrag->data_len += psize; + frag_truesize += psize; + pfrag->offset += frag_truesize; + WRITE_ONCE(msk->write_seq, msk->write_seq + psize); + + /* charge data on mptcp pending queue to the msk socket + * Note: we charge such data both to sk and ssk + */ + sk_wmem_queued_add(sk, frag_truesize); + if (!dfrag_collapsed) { + get_page(dfrag->page); + list_add_tail(&dfrag->list, &msk->rtx_queue); + if (!msk->first_pending) + WRITE_ONCE(msk->first_pending, dfrag); + } + pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk, + dfrag->data_seq, dfrag->data_len, dfrag->already_sent, + !dfrag_collapsed); + + continue; + +wait_for_memory: + mptcp_set_nospace(sk); + __mptcp_push_pending(sk, msg->msg_flags); + ret = sk_stream_wait_memory(sk, &timeo); + if (ret) + goto do_error; + } + + if (copied) + __mptcp_push_pending(sk, msg->msg_flags); + +out: + release_sock(sk); + return copied; + +do_error: + if (copied) + goto out; + + copied = sk_stream_error(sk, msg->msg_flags, ret); + goto out; +} + +static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, + struct msghdr *msg, + size_t len, int flags, + struct scm_timestamping_internal *tss, + int *cmsg_flags) +{ + struct sk_buff *skb, *tmp; + int copied = 0; + + skb_queue_walk_safe(&msk->receive_queue, skb, tmp) { + 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; + + if (!(flags & MSG_TRUNC)) { + err = skb_copy_datagram_msg(skb, offset, msg, count); + if (unlikely(err < 0)) { + if (!copied) + return err; + break; + } + } + + if (MPTCP_SKB_CB(skb)->has_rxtstamp) { + tcp_update_recv_tstamps(skb, tss); + *cmsg_flags |= MPTCP_CMSG_TS; + } + + copied += count; + + if (count < data_len) { + if (!(flags & MSG_PEEK)) { + MPTCP_SKB_CB(skb)->offset += count; + MPTCP_SKB_CB(skb)->map_seq += count; + } + break; + } + + if (!(flags & MSG_PEEK)) { + /* we will bulk release the skb memory later */ + skb->destructor = NULL; + WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize); + __skb_unlink(skb, &msk->receive_queue); + __kfree_skb(skb); + } + + if (copied >= len) + break; + } + + return copied; +} + +/* receive buffer autotuning. See tcp_rcv_space_adjust for more information. + * + * Only difference: Use highest rtt estimate of the subflows in use. + */ +static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) +{ + struct mptcp_subflow_context *subflow; + struct sock *sk = (struct sock *)msk; + u8 scaling_ratio = U8_MAX; + u32 time, advmss = 1; + u64 rtt_us, mstamp; + + msk_owned_by_me(msk); + + if (copied <= 0) + return; + + msk->rcvq_space.copied += copied; + + mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC); + time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time); + + rtt_us = msk->rcvq_space.rtt_us; + if (rtt_us && time < (rtt_us >> 3)) + return; + + rtt_us = 0; + mptcp_for_each_subflow(msk, subflow) { + const struct tcp_sock *tp; + u64 sf_rtt_us; + u32 sf_advmss; + + tp = tcp_sk(mptcp_subflow_tcp_sock(subflow)); + + sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us); + sf_advmss = READ_ONCE(tp->advmss); + + rtt_us = max(sf_rtt_us, rtt_us); + advmss = max(sf_advmss, advmss); + scaling_ratio = min(tp->scaling_ratio, scaling_ratio); + } + + msk->rcvq_space.rtt_us = rtt_us; + msk->scaling_ratio = scaling_ratio; + if (time < (rtt_us >> 3) || rtt_us == 0) + return; + + if (msk->rcvq_space.copied <= msk->rcvq_space.space) + goto new_measure; + + if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) && + !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { + u64 rcvwin, grow; + int rcvbuf; + + rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss; + + grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space); + + do_div(grow, msk->rcvq_space.space); + rcvwin += (grow << 1); + + rcvbuf = min_t(u64, __tcp_space_from_win(scaling_ratio, rcvwin), + READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2])); + + if (rcvbuf > sk->sk_rcvbuf) { + u32 window_clamp; + + window_clamp = __tcp_win_from_space(scaling_ratio, rcvbuf); + WRITE_ONCE(sk->sk_rcvbuf, rcvbuf); + + /* Make subflows follow along. If we do not do this, we + * get drops at subflow level if skbs can't be moved to + * the mptcp rx queue fast enough (announced rcv_win can + * exceed ssk->sk_rcvbuf). + */ + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk; + bool slow; + + ssk = mptcp_subflow_tcp_sock(subflow); + slow = lock_sock_fast(ssk); + WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); + tcp_sk(ssk)->window_clamp = window_clamp; + tcp_cleanup_rbuf(ssk, 1); + unlock_sock_fast(ssk, slow); + } + } + } + + msk->rcvq_space.space = msk->rcvq_space.copied; +new_measure: + msk->rcvq_space.copied = 0; + msk->rcvq_space.time = mstamp; +} + +static void __mptcp_update_rmem(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + if (!msk->rmem_released) + return; + + atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc); + mptcp_rmem_uncharge(sk, msk->rmem_released); + WRITE_ONCE(msk->rmem_released, 0); +} + +static void __mptcp_splice_receive_queue(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue); +} + +static bool __mptcp_move_skbs(struct mptcp_sock *msk) +{ + struct sock *sk = (struct sock *)msk; + unsigned int moved = 0; + bool ret, done; + + do { + struct sock *ssk = mptcp_subflow_recv_lookup(msk); + bool slowpath; + + /* we can have data pending in the subflows only if the msk + * receive buffer was full at subflow_data_ready() time, + * that is an unlikely slow path. + */ + if (likely(!ssk)) + break; + + slowpath = lock_sock_fast(ssk); + mptcp_data_lock(sk); + __mptcp_update_rmem(sk); + done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); + mptcp_data_unlock(sk); + + if (unlikely(ssk->sk_err)) + __mptcp_error_report(sk); + unlock_sock_fast(ssk, slowpath); + } while (!done); + + /* acquire the data lock only if some input data is pending */ + ret = moved > 0; + if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) || + !skb_queue_empty_lockless(&sk->sk_receive_queue)) { + mptcp_data_lock(sk); + __mptcp_update_rmem(sk); + ret |= __mptcp_ofo_queue(msk); + __mptcp_splice_receive_queue(sk); + mptcp_data_unlock(sk); + } + if (ret) + mptcp_check_data_fin((struct sock *)msk); + return !skb_queue_empty(&msk->receive_queue); +} + +static unsigned int mptcp_inq_hint(const struct sock *sk) +{ + const struct mptcp_sock *msk = mptcp_sk(sk); + const struct sk_buff *skb; + + skb = skb_peek(&msk->receive_queue); + if (skb) { + u64 hint_val = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; + + if (hint_val >= INT_MAX) + return INT_MAX; + + return (unsigned int)hint_val; + } + + if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) + return 1; + + return 0; +} + +static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, + int flags, int *addr_len) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + struct scm_timestamping_internal tss; + int copied = 0, cmsg_flags = 0; + int target; + long timeo; + + /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */ + if (unlikely(flags & MSG_ERRQUEUE)) + return inet_recv_error(sk, msg, len, addr_len); + + lock_sock(sk); + if (unlikely(sk->sk_state == TCP_LISTEN)) { + copied = -ENOTCONN; + goto out_err; + } + + timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); + + len = min_t(size_t, len, INT_MAX); + target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); + + if (unlikely(msk->recvmsg_inq)) + cmsg_flags = MPTCP_CMSG_INQ; + + while (copied < len) { + int bytes_read; + + bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags); + if (unlikely(bytes_read < 0)) { + if (!copied) + copied = bytes_read; + goto out_err; + } + + copied += bytes_read; + + /* be sure to advertise window change */ + mptcp_cleanup_rbuf(msk); + + if (skb_queue_empty(&msk->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) { + /* race breaker: the shutdown could be after the + * previous receive queue check + */ + if (__mptcp_move_skbs(msk)) + continue; + 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); + sk_wait_data(sk, &timeo, NULL); + } + +out_err: + if (cmsg_flags && copied >= 0) { + if (cmsg_flags & MPTCP_CMSG_TS) + tcp_recv_timestamp(msg, sk, &tss); + + if (cmsg_flags & MPTCP_CMSG_INQ) { + unsigned int inq = mptcp_inq_hint(sk); + + put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq); + } + } + + pr_debug("msk=%p rx queue empty=%d:%d copied=%d", + msk, skb_queue_empty_lockless(&sk->sk_receive_queue), + skb_queue_empty(&msk->receive_queue), copied); + if (!(flags & MSG_PEEK)) + mptcp_rcv_space_adjust(msk, copied); + + release_sock(sk); + return copied; +} + +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; + struct mptcp_sock *msk = mptcp_sk(sk); + + bh_lock_sock(sk); + if (!sock_owned_by_user(sk)) { + /* we need a process context to retransmit */ + if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags)) + mptcp_schedule_work(sk); + } else { + /* delegate our work to tcp_release_cb() */ + __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags); + } + bh_unlock_sock(sk); + sock_put(sk); +} + +static void mptcp_tout_timer(struct timer_list *t) +{ + struct sock *sk = from_timer(sk, t, sk_timer); + + mptcp_schedule_work(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. + */ +struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk) +{ + struct sock *backup = NULL, *pick = NULL; + struct mptcp_subflow_context *subflow; + int min_stale_count = INT_MAX; + + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + + if (!__mptcp_subflow_active(subflow)) + continue; + + /* still data outstanding at TCP level? skip this */ + if (!tcp_rtx_and_write_queues_empty(ssk)) { + mptcp_pm_subflow_chk_stale(msk, ssk); + min_stale_count = min_t(int, min_stale_count, subflow->stale_count); + continue; + } + + if (subflow->backup) { + if (!backup) + backup = ssk; + continue; + } + + if (!pick) + pick = ssk; + } + + if (pick) + return pick; + + /* use backup only if there are no progresses anywhere */ + return min_stale_count > 1 ? backup : NULL; +} + +bool __mptcp_retransmit_pending_data(struct sock *sk) +{ + struct mptcp_data_frag *cur, *rtx_head; + struct mptcp_sock *msk = mptcp_sk(sk); + + if (__mptcp_check_fallback(msk)) + return false; + + if (tcp_rtx_and_write_queues_empty(sk)) + return false; + + /* the closing socket has some data untransmitted and/or unacked: + * some data in the mptcp rtx queue has not really xmitted yet. + * keep it simple and re-inject the whole mptcp level rtx queue + */ + mptcp_data_lock(sk); + __mptcp_clean_una_wakeup(sk); + rtx_head = mptcp_rtx_head(sk); + if (!rtx_head) { + mptcp_data_unlock(sk); + return false; + } + + msk->recovery_snd_nxt = msk->snd_nxt; + msk->recovery = true; + mptcp_data_unlock(sk); + + msk->first_pending = rtx_head; + msk->snd_burst = 0; + + /* be sure to clear the "sent status" on all re-injected fragments */ + list_for_each_entry(cur, &msk->rtx_queue, list) { + if (!cur->already_sent) + break; + cur->already_sent = 0; + } + + return true; +} + +/* flags for __mptcp_close_ssk() */ +#define MPTCP_CF_PUSH BIT(1) +#define MPTCP_CF_FASTCLOSE BIT(2) + +/* be sure to send a reset only if the caller asked for it, also + * clean completely the subflow status when the subflow reaches + * TCP_CLOSE state + */ +static void __mptcp_subflow_disconnect(struct sock *ssk, + struct mptcp_subflow_context *subflow, + unsigned int flags) +{ + if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) || + (flags & MPTCP_CF_FASTCLOSE)) { + /* The MPTCP code never wait on the subflow sockets, TCP-level + * disconnect should never fail + */ + WARN_ON_ONCE(tcp_disconnect(ssk, 0)); + mptcp_subflow_ctx_reset(subflow); + } else { + tcp_shutdown(ssk, SEND_SHUTDOWN); + } +} + +/* 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, + unsigned int flags) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + bool dispose_it, need_push = false; + + /* If the first subflow moved to a close state before accept, e.g. due + * to an incoming reset or listener shutdown, the subflow socket is + * already deleted by inet_child_forget() and the mptcp socket can't + * survive too. + */ + if (msk->in_accept_queue && msk->first == ssk && + (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) { + /* ensure later check in mptcp_worker() will dispose the msk */ + mptcp_set_close_tout(sk, tcp_jiffies32 - (TCP_TIMEWAIT_LEN + 1)); + sock_set_flag(sk, SOCK_DEAD); + lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); + mptcp_subflow_drop_ctx(ssk); + goto out_release; + } + + dispose_it = msk->free_first || ssk != msk->first; + if (dispose_it) + list_del(&subflow->node); + + lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); + + if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) { + /* be sure to force the tcp_close path + * to generate the egress reset + */ + ssk->sk_lingertime = 0; + sock_set_flag(ssk, SOCK_LINGER); + subflow->send_fastclose = 1; + } + + need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk); + if (!dispose_it) { + __mptcp_subflow_disconnect(ssk, subflow, flags); + release_sock(ssk); + + goto out; + } + + subflow->disposable = 1; + + /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops + * the ssk has been already destroyed, we just need to release the + * reference owned by msk; + */ + if (!inet_csk(ssk)->icsk_ulp_ops) { + WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD)); + kfree_rcu(subflow, rcu); + } else { + /* otherwise tcp will dispose of the ssk and subflow ctx */ + __tcp_close(ssk, 0); + + /* close acquired an extra ref */ + __sock_put(ssk); + } + +out_release: + __mptcp_subflow_error_report(sk, ssk); + release_sock(ssk); + + sock_put(ssk); + + if (ssk == msk->first) + WRITE_ONCE(msk->first, NULL); + +out: + __mptcp_sync_sndbuf(sk); + if (need_push) + __mptcp_push_pending(sk, 0); + + /* Catch every 'all subflows closed' scenario, including peers silently + * closing them, e.g. due to timeout. + * For established sockets, allow an additional timeout before closing, + * as the protocol can still create more subflows. + */ + if (list_is_singular(&msk->conn_list) && msk->first && + inet_sk_state_load(msk->first) == TCP_CLOSE) { + if (sk->sk_state != TCP_ESTABLISHED || + msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) { + inet_sk_state_store(sk, TCP_CLOSE); + mptcp_close_wake_up(sk); + } else { + mptcp_start_tout_timer(sk); + } + } +} + +void mptcp_close_ssk(struct sock *sk, struct sock *ssk, + struct mptcp_subflow_context *subflow) +{ + if (sk->sk_state == TCP_ESTABLISHED) + mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL); + + /* subflow aborted before reaching the fully_established status + * attempt the creation of the next subflow + */ + mptcp_pm_subflow_check_next(mptcp_sk(sk), ssk, subflow); + + __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH); +} + +static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) +{ + return 0; +} + +static void __mptcp_close_subflow(struct sock *sk) +{ + struct mptcp_subflow_context *subflow, *tmp; + struct mptcp_sock *msk = mptcp_sk(sk); + + might_sleep(); + + mptcp_for_each_subflow_safe(msk, subflow, tmp) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + + if (inet_sk_state_load(ssk) != TCP_CLOSE) + continue; + + /* 'subflow_data_ready' will re-sched once rx queue is empty */ + if (!skb_queue_empty_lockless(&ssk->sk_receive_queue)) + continue; + + mptcp_close_ssk(sk, ssk, subflow); + } + +} + +static bool mptcp_close_tout_expired(const struct sock *sk) +{ + if (!inet_csk(sk)->icsk_mtup.probe_timestamp || + sk->sk_state == TCP_CLOSE) + return false; + + return time_after32(tcp_jiffies32, + inet_csk(sk)->icsk_mtup.probe_timestamp + TCP_TIMEWAIT_LEN); +} + +static void mptcp_check_fastclose(struct mptcp_sock *msk) +{ + struct mptcp_subflow_context *subflow, *tmp; + struct sock *sk = (struct sock *)msk; + + if (likely(!READ_ONCE(msk->rcv_fastclose))) + return; + + mptcp_token_destroy(msk); + + mptcp_for_each_subflow_safe(msk, subflow, tmp) { + struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); + bool slow; + + slow = lock_sock_fast(tcp_sk); + if (tcp_sk->sk_state != TCP_CLOSE) { + tcp_send_active_reset(tcp_sk, GFP_ATOMIC); + tcp_set_state(tcp_sk, TCP_CLOSE); + } + unlock_sock_fast(tcp_sk, slow); + } + + /* Mirror the tcp_reset() error propagation */ + switch (sk->sk_state) { + case TCP_SYN_SENT: + WRITE_ONCE(sk->sk_err, ECONNREFUSED); + break; + case TCP_CLOSE_WAIT: + WRITE_ONCE(sk->sk_err, EPIPE); + break; + case TCP_CLOSE: + return; + default: + WRITE_ONCE(sk->sk_err, ECONNRESET); + } + + inet_sk_state_store(sk, TCP_CLOSE); + WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); + smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ + set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags); + + /* the calling mptcp_worker will properly destroy the socket */ + if (sock_flag(sk, SOCK_DEAD)) + return; + + sk->sk_state_change(sk); + sk_error_report(sk); +} + +static void __mptcp_retrans(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + struct mptcp_subflow_context *subflow; + struct mptcp_sendmsg_info info = {}; + struct mptcp_data_frag *dfrag; + struct sock *ssk; + int ret, err; + u16 len = 0; + + mptcp_clean_una_wakeup(sk); + + /* first check ssk: need to kick "stale" logic */ + err = mptcp_sched_get_retrans(msk); + dfrag = mptcp_rtx_head(sk); + if (!dfrag) { + if (mptcp_data_fin_enabled(msk)) { + struct inet_connection_sock *icsk = inet_csk(sk); + + icsk->icsk_retransmits++; + mptcp_set_datafin_timeout(sk); + mptcp_send_ack(msk); + + goto reset_timer; + } + + if (!mptcp_send_head(sk)) + return; + + goto reset_timer; + } + + if (err) + goto reset_timer; + + mptcp_for_each_subflow(msk, subflow) { + if (READ_ONCE(subflow->scheduled)) { + u16 copied = 0; + + mptcp_subflow_set_scheduled(subflow, false); + + ssk = mptcp_subflow_tcp_sock(subflow); + + lock_sock(ssk); + + /* limit retransmission to the bytes already sent on some subflows */ + info.sent = 0; + info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : + dfrag->already_sent; + while (info.sent < info.limit) { + ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); + if (ret <= 0) + break; + + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); + copied += ret; + info.sent += ret; + } + if (copied) { + len = max(copied, len); + tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, + info.size_goal); + WRITE_ONCE(msk->allow_infinite_fallback, false); + } + + release_sock(ssk); + } + } + + msk->bytes_retrans += len; + dfrag->already_sent = max(dfrag->already_sent, len); + +reset_timer: + mptcp_check_and_set_pending(sk); + + if (!mptcp_rtx_timer_pending(sk)) + mptcp_reset_rtx_timer(sk); +} + +/* schedule the timeout timer for the relevant event: either close timeout + * or mp_fail timeout. The close timeout takes precedence on the mp_fail one + */ +void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout) +{ + struct sock *sk = (struct sock *)msk; + unsigned long timeout, close_timeout; + + if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp) + return; + + close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies + + TCP_TIMEWAIT_LEN; + + /* the close timeout takes precedence on the fail one, and here at least one of + * them is active + */ + timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout; + + sk_reset_timer(sk, &sk->sk_timer, timeout); +} + +static void mptcp_mp_fail_no_response(struct mptcp_sock *msk) +{ + struct sock *ssk = msk->first; + bool slow; + + if (!ssk) + return; + + pr_debug("MP_FAIL doesn't respond, reset the subflow"); + + slow = lock_sock_fast(ssk); + mptcp_subflow_reset(ssk); + WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0); + unlock_sock_fast(ssk, slow); +} + +static void mptcp_do_fastclose(struct sock *sk) +{ + struct mptcp_subflow_context *subflow, *tmp; + struct mptcp_sock *msk = mptcp_sk(sk); + + inet_sk_state_store(sk, TCP_CLOSE); + mptcp_for_each_subflow_safe(msk, subflow, tmp) + __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), + subflow, MPTCP_CF_FASTCLOSE); +} + +static void mptcp_worker(struct work_struct *work) +{ + struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); + struct sock *sk = (struct sock *)msk; + unsigned long fail_tout; + int state; + + lock_sock(sk); + state = sk->sk_state; + if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN))) + goto unlock; + + mptcp_check_fastclose(msk); + + mptcp_pm_nl_work(msk); + + mptcp_check_send_data_fin(sk); + mptcp_check_data_fin_ack(sk); + mptcp_check_data_fin(sk); + + if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) + __mptcp_close_subflow(sk); + + if (mptcp_close_tout_expired(sk)) { + mptcp_do_fastclose(sk); + mptcp_close_wake_up(sk); + } + + if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) { + __mptcp_destroy_sock(sk); + goto unlock; + } + + if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) + __mptcp_retrans(sk); + + fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0; + if (fail_tout && time_after(jiffies, fail_tout)) + mptcp_mp_fail_no_response(msk); + +unlock: + release_sock(sk); + sock_put(sk); +} + +static void __mptcp_init_sock(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + INIT_LIST_HEAD(&msk->conn_list); + INIT_LIST_HEAD(&msk->join_list); + INIT_LIST_HEAD(&msk->rtx_queue); + INIT_WORK(&msk->work, mptcp_worker); + __skb_queue_head_init(&msk->receive_queue); + msk->out_of_order_queue = RB_ROOT; + msk->first_pending = NULL; + msk->rmem_fwd_alloc = 0; + WRITE_ONCE(msk->rmem_released, 0); + msk->timer_ival = TCP_RTO_MIN; + + WRITE_ONCE(msk->first, NULL); + inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; + WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); + WRITE_ONCE(msk->allow_infinite_fallback, true); + msk->recovery = false; + msk->subflow_id = 1; + + 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); + timer_setup(&sk->sk_timer, mptcp_tout_timer, 0); +} + +static void mptcp_ca_reset(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + tcp_assign_congestion_control(sk); + strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name); + + /* no need to keep a reference to the ops, the name will suffice */ + tcp_cleanup_congestion_control(sk); + icsk->icsk_ca_ops = NULL; +} + +static int mptcp_init_sock(struct sock *sk) +{ + struct net *net = sock_net(sk); + int ret; + + __mptcp_init_sock(sk); + + if (!mptcp_is_enabled(net)) + return -ENOPROTOOPT; + + if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) + return -ENOMEM; + + ret = mptcp_init_sched(mptcp_sk(sk), + mptcp_sched_find(mptcp_get_scheduler(net))); + if (ret) + return ret; + + set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags); + + /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will + * propagate the correct value + */ + mptcp_ca_reset(sk); + + sk_sockets_allocated_inc(sk); + sk->sk_rcvbuf = READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]); + sk->sk_sndbuf = READ_ONCE(net->ipv4.sysctl_tcp_wmem[1]); + + return 0; +} + +static void __mptcp_clear_xmit(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + struct mptcp_data_frag *dtmp, *dfrag; + + WRITE_ONCE(msk->first_pending, NULL); + list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) + dfrag_clear(sk, dfrag); +} + +void mptcp_cancel_work(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + if (cancel_work_sync(&msk->work)) + __sock_put(sk); +} + +void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) +{ + lock_sock(ssk); + + switch (ssk->sk_state) { + case TCP_LISTEN: + if (!(how & RCV_SHUTDOWN)) + break; + fallthrough; + case TCP_SYN_SENT: + WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK)); + break; + default: + if (__mptcp_check_fallback(mptcp_sk(sk))) { + pr_debug("Fallback"); + ssk->sk_shutdown |= how; + tcp_shutdown(ssk, how); + + /* simulate the data_fin ack reception to let the state + * machine move forward + */ + WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt); + mptcp_schedule_work(sk); + } else { + pr_debug("Sending DATA_FIN on subflow %p", ssk); + tcp_send_ack(ssk); + if (!mptcp_rtx_timer_pending(sk)) + mptcp_reset_rtx_timer(sk); + } + break; + } + + release_sock(ssk); +} + +static const unsigned char new_state[16] = { + /* current state: new state: action: */ + [0 /* (Invalid) */] = TCP_CLOSE, + [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, + [TCP_SYN_SENT] = TCP_CLOSE, + [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, + [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, + [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, + [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */ + [TCP_CLOSE] = TCP_CLOSE, + [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, + [TCP_LAST_ACK] = TCP_LAST_ACK, + [TCP_LISTEN] = TCP_CLOSE, + [TCP_CLOSING] = TCP_CLOSING, + [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ +}; + +static int mptcp_close_state(struct sock *sk) +{ + int next = (int)new_state[sk->sk_state]; + int ns = next & TCP_STATE_MASK; + + inet_sk_state_store(sk, ns); + + return next & TCP_ACTION_FIN; +} + +static void mptcp_check_send_data_fin(struct sock *sk) +{ + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk = mptcp_sk(sk); + + pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu", + msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk), + msk->snd_nxt, msk->write_seq); + + /* we still need to enqueue subflows or not really shutting down, + * skip this + */ + if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq || + mptcp_send_head(sk)) + return; + + WRITE_ONCE(msk->snd_nxt, msk->write_seq); + + mptcp_for_each_subflow(msk, subflow) { + struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); + + mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN); + } +} + +static void __mptcp_wr_shutdown(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d", + msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state, + !!mptcp_send_head(sk)); + + /* will be ignored by fallback sockets */ + WRITE_ONCE(msk->write_seq, msk->write_seq + 1); + WRITE_ONCE(msk->snd_data_fin_enable, 1); + + mptcp_check_send_data_fin(sk); +} + +static void __mptcp_destroy_sock(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + pr_debug("msk=%p", msk); + + might_sleep(); + + mptcp_stop_rtx_timer(sk); + sk_stop_timer(sk, &sk->sk_timer); + msk->pm.status = 0; + mptcp_release_sched(msk); + + sk->sk_prot->destroy(sk); + + WARN_ON_ONCE(msk->rmem_fwd_alloc); + WARN_ON_ONCE(msk->rmem_released); + sk_stream_kill_queues(sk); + xfrm_sk_free_policy(sk); + + sock_put(sk); +} + +void __mptcp_unaccepted_force_close(struct sock *sk) +{ + sock_set_flag(sk, SOCK_DEAD); + mptcp_do_fastclose(sk); + __mptcp_destroy_sock(sk); +} + +static __poll_t mptcp_check_readable(struct mptcp_sock *msk) +{ + /* Concurrent splices from sk_receive_queue into receive_queue will + * always show at least one non-empty queue when checked in this order. + */ + if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) && + skb_queue_empty_lockless(&msk->receive_queue)) + return 0; + + return EPOLLIN | EPOLLRDNORM; +} + +static void mptcp_check_listen_stop(struct sock *sk) +{ + struct sock *ssk; + + if (inet_sk_state_load(sk) != TCP_LISTEN) + return; + + sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); + ssk = mptcp_sk(sk)->first; + if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN)) + return; + + lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); + tcp_set_state(ssk, TCP_CLOSE); + mptcp_subflow_queue_clean(sk, ssk); + inet_csk_listen_stop(ssk); + mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED); + release_sock(ssk); +} + +bool __mptcp_close(struct sock *sk, long timeout) +{ + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk = mptcp_sk(sk); + bool do_cancel_work = false; + int subflows_alive = 0; + + WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); + + if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) { + mptcp_check_listen_stop(sk); + inet_sk_state_store(sk, TCP_CLOSE); + goto cleanup; + } + + if (mptcp_check_readable(msk) || timeout < 0) { + /* If the msk has read data, or the caller explicitly ask it, + * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose + */ + mptcp_do_fastclose(sk); + timeout = 0; + } else if (mptcp_close_state(sk)) { + __mptcp_wr_shutdown(sk); + } + + sk_stream_wait_close(sk, timeout); + +cleanup: + /* orphan all the subflows */ + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + bool slow = lock_sock_fast_nested(ssk); + + subflows_alive += ssk->sk_state != TCP_CLOSE; + + /* since the close timeout takes precedence on the fail one, + * cancel the latter + */ + if (ssk == msk->first) + subflow->fail_tout = 0; + + /* detach from the parent socket, but allow data_ready to + * push incoming data into the mptcp stack, to properly ack it + */ + ssk->sk_socket = NULL; + ssk->sk_wq = NULL; + unlock_sock_fast(ssk, slow); + } + sock_orphan(sk); + + /* all the subflows are closed, only timeout can change the msk + * state, let's not keep resources busy for no reasons + */ + if (subflows_alive == 0) + inet_sk_state_store(sk, TCP_CLOSE); + + sock_hold(sk); + pr_debug("msk=%p state=%d", sk, sk->sk_state); + if (msk->token) + mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); + + if (sk->sk_state == TCP_CLOSE) { + __mptcp_destroy_sock(sk); + do_cancel_work = true; + } else { + mptcp_start_tout_timer(sk); + } + + return do_cancel_work; +} + +static void mptcp_close(struct sock *sk, long timeout) +{ + bool do_cancel_work; + + lock_sock(sk); + + do_cancel_work = __mptcp_close(sk, timeout); + release_sock(sk); + if (do_cancel_work) + mptcp_cancel_work(sk); + + sock_put(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) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + /* We are on the fastopen error path. We can't call straight into the + * subflows cleanup code due to lock nesting (we are already under + * msk->firstsocket lock). + */ + if (msk->fastopening) + return -EBUSY; + + mptcp_check_listen_stop(sk); + inet_sk_state_store(sk, TCP_CLOSE); + + mptcp_stop_rtx_timer(sk); + mptcp_stop_tout_timer(sk); + + if (msk->token) + mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); + + /* msk->subflow is still intact, the following will not free the first + * subflow + */ + mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE); + WRITE_ONCE(msk->flags, 0); + msk->cb_flags = 0; + msk->push_pending = 0; + msk->recovery = false; + msk->can_ack = false; + msk->fully_established = false; + msk->rcv_data_fin = false; + msk->snd_data_fin_enable = false; + msk->rcv_fastclose = false; + msk->use_64bit_ack = false; + WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); + mptcp_pm_data_reset(msk); + mptcp_ca_reset(sk); + msk->bytes_acked = 0; + msk->bytes_received = 0; + msk->bytes_sent = 0; + msk->bytes_retrans = 0; + + WRITE_ONCE(sk->sk_shutdown, 0); + sk_error_report(sk); + return 0; +} + +#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_init(const struct sock *sk, + const struct mptcp_options_received *mp_opt, + struct sock *ssk, + 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; + + 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->in_accept_queue = 1; + WRITE_ONCE(msk->fully_established, false); + if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD) + WRITE_ONCE(msk->csum_enabled, true); + + msk->write_seq = subflow_req->idsn + 1; + msk->snd_nxt = msk->write_seq; + msk->snd_una = msk->write_seq; + msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd; + msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq; + mptcp_init_sched(msk, mptcp_sk(sk)->sched); + + /* passive msk is created after the first/MPC subflow */ + msk->subflow_id = 2; + + sock_reset_flag(nsk, SOCK_RCU_FREE); + security_inet_csk_clone(nsk, req); + + /* this can't race with mptcp_close(), as the msk is + * not yet exposted to user-space + */ + inet_sk_state_store(nsk, TCP_ESTABLISHED); + + /* The msk maintain a ref to each subflow in the connections list */ + WRITE_ONCE(msk->first, ssk); + list_add(&mptcp_subflow_ctx(ssk)->node, &msk->conn_list); + sock_hold(ssk); + + /* new mpc subflow takes ownership of the newly + * created mptcp socket + */ + mptcp_token_accept(subflow_req, msk); + + /* set msk addresses early to ensure mptcp_pm_get_local_id() + * uses the correct data + */ + mptcp_copy_inaddrs(nsk, ssk); + __mptcp_propagate_sndbuf(nsk, ssk); + + mptcp_rcv_space_init(msk, ssk); + bh_unlock_sock(nsk); + + /* note: the newly allocated socket refcount is 2 now */ + return nsk; +} + +void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) +{ + const struct tcp_sock *tp = tcp_sk(ssk); + + msk->rcvq_space.copied = 0; + msk->rcvq_space.rtt_us = 0; + + msk->rcvq_space.time = tp->tcp_mstamp; + + /* initial rcv_space offering made to peer */ + msk->rcvq_space.space = min_t(u32, tp->rcv_wnd, + TCP_INIT_CWND * tp->advmss); + if (msk->rcvq_space.space == 0) + msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; + + WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); +} + +static struct sock *mptcp_accept(struct sock *ssk, int flags, int *err, + bool kern) +{ + struct sock *newsk; + + pr_debug("ssk=%p, listener=%p", ssk, mptcp_subflow_ctx(ssk)); + newsk = inet_csk_accept(ssk, flags, err, kern); + if (!newsk) + return NULL; + + pr_debug("newsk=%p, subflow is mptcp=%d", newsk, sk_is_mptcp(newsk)); + if (sk_is_mptcp(newsk)) { + struct mptcp_subflow_context *subflow; + struct sock *new_mptcp_sock; + + 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; + goto out; + } + + newsk = new_mptcp_sock; + MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK); + } else { + MPTCP_INC_STATS(sock_net(ssk), + MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); + } + +out: + newsk->sk_kern_sock = kern; + return newsk; +} + +void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags) +{ + struct mptcp_subflow_context *subflow, *tmp; + struct sock *sk = (struct sock *)msk; + + __mptcp_clear_xmit(sk); + + /* join list will be eventually flushed (with rst) at sock lock release time */ + mptcp_for_each_subflow_safe(msk, subflow, tmp) + __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags); + + /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ + mptcp_data_lock(sk); + skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue); + __skb_queue_purge(&sk->sk_receive_queue); + skb_rbtree_purge(&msk->out_of_order_queue); + mptcp_data_unlock(sk); + + /* move all the rx fwd alloc into the sk_mem_reclaim_final in + * inet_sock_destruct() will dispose it + */ + sk_forward_alloc_add(sk, msk->rmem_fwd_alloc); + WRITE_ONCE(msk->rmem_fwd_alloc, 0); + mptcp_token_destroy(msk); + mptcp_pm_free_anno_list(msk); + mptcp_free_local_addr_list(msk); +} + +static void mptcp_destroy(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + /* allow the following to close even the initial subflow */ + msk->free_first = 1; + mptcp_destroy_common(msk, 0); + sk_sockets_allocated_dec(sk); +} + +void __mptcp_data_acked(struct sock *sk) +{ + if (!sock_owned_by_user(sk)) + __mptcp_clean_una(sk); + else + __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags); + + if (mptcp_pending_data_fin_ack(sk)) + mptcp_schedule_work(sk); +} + +void __mptcp_check_push(struct sock *sk, struct sock *ssk) +{ + if (!mptcp_send_head(sk)) + return; + + if (!sock_owned_by_user(sk)) + __mptcp_subflow_push_pending(sk, ssk, false); + else + __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); +} + +#define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \ + BIT(MPTCP_RETRANSMIT) | \ + BIT(MPTCP_FLUSH_JOIN_LIST)) + +/* processes deferred events and flush wmem */ +static void mptcp_release_cb(struct sock *sk) + __must_hold(&sk->sk_lock.slock) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + for (;;) { + unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED) | + msk->push_pending; + struct list_head join_list; + + if (!flags) + break; + + INIT_LIST_HEAD(&join_list); + list_splice_init(&msk->join_list, &join_list); + + /* the following actions acquire the subflow socket lock + * + * 1) can't be invoked in atomic scope + * 2) must avoid ABBA deadlock with msk socket spinlock: the RX + * datapath acquires the msk socket spinlock while helding + * the subflow socket lock + */ + msk->push_pending = 0; + msk->cb_flags &= ~flags; + spin_unlock_bh(&sk->sk_lock.slock); + + if (flags & BIT(MPTCP_FLUSH_JOIN_LIST)) + __mptcp_flush_join_list(sk, &join_list); + if (flags & BIT(MPTCP_PUSH_PENDING)) + __mptcp_push_pending(sk, 0); + if (flags & BIT(MPTCP_RETRANSMIT)) + __mptcp_retrans(sk); + + cond_resched(); + spin_lock_bh(&sk->sk_lock.slock); + } + + if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags)) + __mptcp_clean_una_wakeup(sk); + if (unlikely(msk->cb_flags)) { + /* be sure to sync the msk state before taking actions + * depending on sk_state (MPTCP_ERROR_REPORT) + * On sk release avoid actions depending on the first subflow + */ + if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first) + __mptcp_sync_state(sk, msk->pending_state); + if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags)) + __mptcp_error_report(sk); + if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags)) + __mptcp_sync_sndbuf(sk); + } + + __mptcp_update_rmem(sk); +} + +/* MP_JOIN client subflow must wait for 4th ack before sending any data: + * TCP can't schedule delack timer before the subflow is fully established. + * MPTCP uses the delack timer to do 3rd ack retransmissions + */ +static void schedule_3rdack_retransmission(struct sock *ssk) +{ + struct inet_connection_sock *icsk = inet_csk(ssk); + struct tcp_sock *tp = tcp_sk(ssk); + unsigned long timeout; + + if (mptcp_subflow_ctx(ssk)->fully_established) + return; + + /* reschedule with a timeout above RTT, as we must look only for drop */ + if (tp->srtt_us) + timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1)); + else + timeout = TCP_TIMEOUT_INIT; + timeout += jiffies; + + WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); + icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; + icsk->icsk_ack.timeout = timeout; + sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout); +} + +void mptcp_subflow_process_delegated(struct sock *ssk, long status) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + struct sock *sk = subflow->conn; + + if (status & BIT(MPTCP_DELEGATE_SEND)) { + mptcp_data_lock(sk); + if (!sock_owned_by_user(sk)) + __mptcp_subflow_push_pending(sk, ssk, true); + else + __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); + mptcp_data_unlock(sk); + } + if (status & BIT(MPTCP_DELEGATE_SNDBUF)) { + mptcp_data_lock(sk); + if (!sock_owned_by_user(sk)) + __mptcp_sync_sndbuf(sk); + else + __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags); + mptcp_data_unlock(sk); + } + if (status & BIT(MPTCP_DELEGATE_ACK)) + schedule_3rdack_retransmission(ssk); +} + +static int mptcp_hash(struct sock *sk) +{ + /* should never be called, + * we hash the TCP subflows not the master socket + */ + WARN_ON_ONCE(1); + return 0; +} + +static void mptcp_unhash(struct sock *sk) +{ + /* called from sk_common_release(), but nothing to do here */ +} + +static int mptcp_get_port(struct sock *sk, unsigned short snum) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + pr_debug("msk=%p, ssk=%p", msk, msk->first); + if (WARN_ON_ONCE(!msk->first)) + return -EINVAL; + + return inet_csk_get_port(msk->first, snum); +} + +void mptcp_finish_connect(struct sock *ssk) +{ + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk; + struct sock *sk; + + subflow = mptcp_subflow_ctx(ssk); + sk = subflow->conn; + msk = mptcp_sk(sk); + + pr_debug("msk=%p, token=%u", sk, subflow->token); + + subflow->map_seq = subflow->iasn; + subflow->map_subflow_seq = 1; + + /* the socket is not connected yet, no msk/subflow ops can access/race + * accessing the field below + */ + WRITE_ONCE(msk->local_key, subflow->local_key); + WRITE_ONCE(msk->write_seq, subflow->idsn + 1); + WRITE_ONCE(msk->snd_nxt, msk->write_seq); + WRITE_ONCE(msk->snd_una, msk->write_seq); + + mptcp_pm_new_connection(msk, ssk, 0); + + mptcp_rcv_space_init(msk, ssk); +} + +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 *ssk) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + struct mptcp_sock *msk = mptcp_sk(subflow->conn); + struct sock *parent = (void *)msk; + bool ret = true; + + pr_debug("msk=%p, subflow=%p", msk, subflow); + + /* mptcp socket already closing? */ + if (!mptcp_is_fully_established(parent)) { + subflow->reset_reason = MPTCP_RST_EMPTCP; + return false; + } + + /* active subflow, already present inside the conn_list */ + if (!list_empty(&subflow->node)) { + mptcp_subflow_joined(msk, ssk); + mptcp_propagate_sndbuf(parent, ssk); + return true; + } + + if (!mptcp_pm_allow_new_subflow(msk)) + goto err_prohibited; + + /* If we can't acquire msk socket lock here, let the release callback + * handle it + */ + mptcp_data_lock(parent); + if (!sock_owned_by_user(parent)) { + ret = __mptcp_finish_join(msk, ssk); + if (ret) { + sock_hold(ssk); + list_add_tail(&subflow->node, &msk->conn_list); + } + } else { + sock_hold(ssk); + list_add_tail(&subflow->node, &msk->join_list); + __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags); + } + mptcp_data_unlock(parent); + + if (!ret) { +err_prohibited: + subflow->reset_reason = MPTCP_RST_EPROHIBIT; + return false; + } + + return true; +} + +static void mptcp_shutdown(struct sock *sk, int how) +{ + pr_debug("sk=%p, how=%d", sk, how); + + if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk)) + __mptcp_wr_shutdown(sk); +} + +static int mptcp_forward_alloc_get(const struct sock *sk) +{ + return READ_ONCE(sk->sk_forward_alloc) + + READ_ONCE(mptcp_sk(sk)->rmem_fwd_alloc); +} + +static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v) +{ + const struct sock *sk = (void *)msk; + u64 delta; + + if (sk->sk_state == TCP_LISTEN) + return -EINVAL; + + if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) + return 0; + + delta = msk->write_seq - v; + if (__mptcp_check_fallback(msk) && msk->first) { + struct tcp_sock *tp = tcp_sk(msk->first); + + /* the first subflow is disconnected after close - see + * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq + * so ignore that status, too. + */ + if (!((1 << msk->first->sk_state) & + (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))) + delta += READ_ONCE(tp->write_seq) - tp->snd_una; + } + if (delta > INT_MAX) + delta = INT_MAX; + + return (int)delta; +} + +static int mptcp_ioctl(struct sock *sk, int cmd, int *karg) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + bool slow; + + switch (cmd) { + case SIOCINQ: + if (sk->sk_state == TCP_LISTEN) + return -EINVAL; + + lock_sock(sk); + __mptcp_move_skbs(msk); + *karg = mptcp_inq_hint(sk); + release_sock(sk); + break; + case SIOCOUTQ: + slow = lock_sock_fast(sk); + *karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una)); + unlock_sock_fast(sk, slow); + break; + case SIOCOUTQNSD: + slow = lock_sock_fast(sk); + *karg = mptcp_ioctl_outq(msk, msk->snd_nxt); + unlock_sock_fast(sk, slow); + break; + default: + return -ENOIOCTLCMD; + } + + return 0; +} + +static void mptcp_subflow_early_fallback(struct mptcp_sock *msk, + struct mptcp_subflow_context *subflow) +{ + subflow->request_mptcp = 0; + __mptcp_do_fallback(msk); +} + +static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) +{ + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk = mptcp_sk(sk); + int err = -EINVAL; + struct sock *ssk; + + ssk = __mptcp_nmpc_sk(msk); + if (IS_ERR(ssk)) + return PTR_ERR(ssk); + + inet_sk_state_store(sk, TCP_SYN_SENT); + subflow = mptcp_subflow_ctx(ssk); +#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(ssk)->md5sig_info)) + mptcp_subflow_early_fallback(msk, subflow); +#endif + if (subflow->request_mptcp && mptcp_token_new_connect(ssk)) { + MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_TOKENFALLBACKINIT); + mptcp_subflow_early_fallback(msk, subflow); + } + if (likely(!__mptcp_check_fallback(msk))) + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE); + + /* if reaching here via the fastopen/sendmsg path, the caller already + * acquired the subflow socket lock, too. + */ + if (!msk->fastopening) + lock_sock(ssk); + + /* the following mirrors closely a very small chunk of code from + * __inet_stream_connect() + */ + if (ssk->sk_state != TCP_CLOSE) + goto out; + + if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) { + err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len); + if (err) + goto out; + } + + err = ssk->sk_prot->connect(ssk, uaddr, addr_len); + if (err < 0) + goto out; + + inet_assign_bit(DEFER_CONNECT, sk, inet_test_bit(DEFER_CONNECT, ssk)); + +out: + if (!msk->fastopening) + release_sock(ssk); + + /* on successful connect, the msk state will be moved to established by + * subflow_finish_connect() + */ + if (unlikely(err)) { + /* avoid leaving a dangling token in an unconnected socket */ + mptcp_token_destroy(msk); + inet_sk_state_store(sk, TCP_CLOSE); + return err; + } + + mptcp_copy_inaddrs(sk, ssk); + return 0; +} + +static struct proto mptcp_prot = { + .name = "MPTCP", + .owner = THIS_MODULE, + .init = mptcp_init_sock, + .connect = mptcp_connect, + .disconnect = mptcp_disconnect, + .close = mptcp_close, + .accept = mptcp_accept, + .setsockopt = mptcp_setsockopt, + .getsockopt = mptcp_getsockopt, + .shutdown = mptcp_shutdown, + .destroy = mptcp_destroy, + .sendmsg = mptcp_sendmsg, + .ioctl = mptcp_ioctl, + .recvmsg = mptcp_recvmsg, + .release_cb = mptcp_release_cb, + .hash = mptcp_hash, + .unhash = mptcp_unhash, + .get_port = mptcp_get_port, + .forward_alloc_get = mptcp_forward_alloc_get, + .sockets_allocated = &mptcp_sockets_allocated, + + .memory_allocated = &tcp_memory_allocated, + .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc, + + .memory_pressure = &tcp_memory_pressure, + .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), + .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), + .sysctl_mem = sysctl_tcp_mem, + .obj_size = sizeof(struct mptcp_sock), + .slab_flags = SLAB_TYPESAFE_BY_RCU, + .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 sock *ssk, *sk = sock->sk; + int err = -EINVAL; + + lock_sock(sk); + ssk = __mptcp_nmpc_sk(msk); + if (IS_ERR(ssk)) { + err = PTR_ERR(ssk); + goto unlock; + } + + if (sk->sk_family == AF_INET) + err = inet_bind_sk(ssk, uaddr, addr_len); +#if IS_ENABLED(CONFIG_MPTCP_IPV6) + else if (sk->sk_family == AF_INET6) + err = inet6_bind_sk(ssk, uaddr, addr_len); +#endif + if (!err) + mptcp_copy_inaddrs(sk, ssk); + +unlock: + release_sock(sk); + return err; +} + +static int mptcp_listen(struct socket *sock, int backlog) +{ + struct mptcp_sock *msk = mptcp_sk(sock->sk); + struct sock *sk = sock->sk; + struct sock *ssk; + int err; + + pr_debug("msk=%p", msk); + + lock_sock(sk); + + err = -EINVAL; + if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM) + goto unlock; + + ssk = __mptcp_nmpc_sk(msk); + if (IS_ERR(ssk)) { + err = PTR_ERR(ssk); + goto unlock; + } + + inet_sk_state_store(sk, TCP_LISTEN); + sock_set_flag(sk, SOCK_RCU_FREE); + + lock_sock(ssk); + err = __inet_listen_sk(ssk, backlog); + release_sock(ssk); + inet_sk_state_store(sk, inet_sk_state_load(ssk)); + + if (!err) { + sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); + mptcp_copy_inaddrs(sk, ssk); + mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED); + } + +unlock: + release_sock(sk); + return err; +} + +static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, + int flags, bool kern) +{ + struct mptcp_sock *msk = mptcp_sk(sock->sk); + struct sock *ssk, *newsk; + int err; + + pr_debug("msk=%p", msk); + + /* Buggy applications can call accept on socket states other then LISTEN + * but no need to allocate the first subflow just to error out. + */ + ssk = READ_ONCE(msk->first); + if (!ssk) + return -EINVAL; + + newsk = mptcp_accept(ssk, flags, &err, kern); + if (!newsk) + return err; + + lock_sock(newsk); + + __inet_accept(sock, newsock, newsk); + if (!mptcp_is_tcpsk(newsock->sk)) { + struct mptcp_sock *msk = mptcp_sk(newsk); + struct mptcp_subflow_context *subflow; + + set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags); + msk->in_accept_queue = 0; + + /* set ssk->sk_socket of accept()ed flows to mptcp socket. + * This is needed so NOSPACE flag can be set from tcp stack. + */ + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + + if (!ssk->sk_socket) + mptcp_sock_graft(ssk, newsock); + } + + /* Do late cleanup for the first subflow as necessary. Also + * deal with bad peers not doing a complete shutdown. + */ + if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) { + __mptcp_close_ssk(newsk, msk->first, + mptcp_subflow_ctx(msk->first), 0); + if (unlikely(list_is_singular(&msk->conn_list))) + inet_sk_state_store(newsk, TCP_CLOSE); + } + } + release_sock(newsk); + + return 0; +} + +static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) +{ + struct sock *sk = (struct sock *)msk; + + if (sk_stream_is_writeable(sk)) + return EPOLLOUT | EPOLLWRNORM; + + mptcp_set_nospace(sk); + smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */ + if (sk_stream_is_writeable(sk)) + return EPOLLOUT | EPOLLWRNORM; + + return 0; +} + +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; + __poll_t mask = 0; + u8 shutdown; + int state; + + msk = mptcp_sk(sk); + sock_poll_wait(file, sock, wait); + + state = inet_sk_state_load(sk); + pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags); + if (state == TCP_LISTEN) { + struct sock *ssk = READ_ONCE(msk->first); + + if (WARN_ON_ONCE(!ssk)) + return 0; + + return inet_csk_listen_poll(ssk); + } + + shutdown = READ_ONCE(sk->sk_shutdown); + if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE) + mask |= EPOLLHUP; + if (shutdown & RCV_SHUTDOWN) + mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; + + if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { + mask |= mptcp_check_readable(msk); + if (shutdown & SEND_SHUTDOWN) + mask |= EPOLLOUT | EPOLLWRNORM; + else + mask |= mptcp_check_writeable(msk); + } else if (state == TCP_SYN_SENT && + inet_test_bit(DEFER_CONNECT, sk)) { + /* cf tcp_poll() note about TFO */ + mask |= EPOLLOUT | EPOLLWRNORM; + } + + /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */ + smp_rmb(); + if (READ_ONCE(sk->sk_err)) + mask |= EPOLLERR; + + return mask; +} + +static const struct proto_ops mptcp_stream_ops = { + .family = PF_INET, + .owner = THIS_MODULE, + .release = inet_release, + .bind = mptcp_bind, + .connect = inet_stream_connect, + .socketpair = sock_no_socketpair, + .accept = mptcp_stream_accept, + .getname = inet_getname, + .poll = mptcp_poll, + .ioctl = inet_ioctl, + .gettstamp = sock_gettstamp, + .listen = mptcp_listen, + .shutdown = inet_shutdown, + .setsockopt = sock_common_setsockopt, + .getsockopt = sock_common_getsockopt, + .sendmsg = inet_sendmsg, + .recvmsg = inet_recvmsg, + .mmap = sock_no_mmap, +}; + +static struct inet_protosw mptcp_protosw = { + .type = SOCK_STREAM, + .protocol = IPPROTO_MPTCP, + .prot = &mptcp_prot, + .ops = &mptcp_stream_ops, + .flags = INET_PROTOSW_ICSK, +}; + +static int mptcp_napi_poll(struct napi_struct *napi, int budget) +{ + struct mptcp_delegated_action *delegated; + struct mptcp_subflow_context *subflow; + int work_done = 0; + + delegated = container_of(napi, struct mptcp_delegated_action, napi); + while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + + bh_lock_sock_nested(ssk); + if (!sock_owned_by_user(ssk)) { + mptcp_subflow_process_delegated(ssk, xchg(&subflow->delegated_status, 0)); + } else { + /* tcp_release_cb_override already processed + * the action or will do at next release_sock(). + * In both case must dequeue the subflow here - on the same + * CPU that scheduled it. + */ + smp_wmb(); + clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status); + } + bh_unlock_sock(ssk); + sock_put(ssk); + + if (++work_done == budget) + return budget; + } + + /* always provide a 0 'work_done' argument, so that napi_complete_done + * will not try accessing the NULL napi->dev ptr + */ + napi_complete_done(napi, 0); + return work_done; +} + +void __init mptcp_proto_init(void) +{ + struct mptcp_delegated_action *delegated; + int cpu; + + 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"); + + init_dummy_netdev(&mptcp_napi_dev); + for_each_possible_cpu(cpu) { + delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu); + INIT_LIST_HEAD(&delegated->head); + netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi, + mptcp_napi_poll); + napi_enable(&delegated->napi); + } + + mptcp_subflow_init(); + mptcp_pm_init(); + mptcp_sched_init(); + mptcp_token_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 = inet_stream_connect, + .socketpair = sock_no_socketpair, + .accept = mptcp_stream_accept, + .getname = inet6_getname, + .poll = mptcp_poll, + .ioctl = inet6_ioctl, + .gettstamp = sock_gettstamp, + .listen = mptcp_listen, + .shutdown = inet_shutdown, + .setsockopt = sock_common_setsockopt, + .getsockopt = sock_common_getsockopt, + .sendmsg = inet6_sendmsg, + .recvmsg = inet6_recvmsg, + .mmap = sock_no_mmap, +#ifdef CONFIG_COMPAT + .compat_ioctl = inet6_compat_ioctl, +#endif +}; + +static struct proto mptcp_v6_prot; + +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 __init 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.obj_size = sizeof(struct mptcp6_sock); + mptcp_v6_prot.ipv6_pinfo_offset = offsetof(struct mptcp6_sock, np); + + 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 |