net: mptcp: improve fallback to TCP (e1ff9e82) · Commits · 戴 / test

net/mptcp/options.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -624,6 +624,9 @@ bool mptcp_established_options(struct sock sk, struct sk_buff skb,

		opts->suboptions = 0;

		if (unlikely(mptcp_check_fallback(sk)))
		return false;

		if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts))
		ret = true;
		else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining,
		@@ -714,7 +717,8 @@ static bool check_fully_established(struct mptcp_sock msk, struct sock sk,
		*/
		if (!mp_opt->mp_capable) {
		subflow->mp_capable = 0;
		tcp_sk(sk)->is_mptcp = 0;
		pr_fallback(msk);
		__mptcp_do_fallback(msk);
		return false;
		}

		@@ -814,6 +818,9 @@ void mptcp_incoming_options(struct sock sk, struct sk_buff skb,
		struct mptcp_options_received mp_opt;
		struct mptcp_ext *mpext;

		if (__mptcp_check_fallback(msk))
		return;

		mptcp_get_options(skb, &mp_opt);
		if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
		return;

net/mptcp/protocol.c

+26 −72

Original line number	Diff line number	Diff line
		@@ -52,11 +52,6 @@ static struct socket __mptcp_nmpc_socket(const struct mptcp_sock msk)
		return msk->subflow;
		}

		static bool __mptcp_needs_tcp_fallback(const struct mptcp_sock *msk)
		{
		return msk->first && !sk_is_mptcp(msk->first);
		}

		static struct socket mptcp_is_tcpsk(struct sock sk)
		{
		struct socket *sock = sk->sk_socket;
		@@ -94,7 +89,7 @@ static struct socket __mptcp_tcp_fallback(struct mptcp_sock msk)
		if (unlikely(sock))
		return sock;

		if (likely(!__mptcp_needs_tcp_fallback(msk)))
		if (likely(!__mptcp_check_fallback(msk)))
		return NULL;

		return msk->subflow;
		@@ -133,6 +128,11 @@ static struct socket __mptcp_socket_create(struct mptcp_sock msk, int state)
		list_add(&subflow->node, &msk->conn_list);
		subflow->request_mptcp = 1;

		/* accept() will wait on first subflow sk_wq, and we always wakes up
		* via msk->sk_socket
		*/
		RCU_INIT_POINTER(msk->first->sk_wq, &sk->sk_socket->wq);

		set_state:
		if (state != MPTCP_SAME_STATE)
		inet_sk_state_store(sk, state);
		@@ -229,6 +229,15 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
		if (!skb)
		break;

		if (__mptcp_check_fallback(msk)) {
		/* if we are running under the workqueue, TCP could have
		* collapsed skbs between dummy map creation and now
		* be sure to adjust the 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) {
		@@ -466,8 +475,15 @@ static void mptcp_clean_una(struct sock *sk)
		{
		struct mptcp_sock *msk = mptcp_sk(sk);
		struct mptcp_data_frag dtmp, dfrag;
		u64 snd_una = atomic64_read(&msk->snd_una);
		bool cleaned = false;
		u64 snd_una;

		/* on fallback we just need to ignore snd_una, as this is really
		* plain TCP
		*/
		if (__mptcp_check_fallback(msk))
		atomic64_set(&msk->snd_una, msk->write_seq);
		snd_una = atomic64_read(&msk->snd_una);

		list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
		if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
		@@ -740,7 +756,6 @@ static int mptcp_sendmsg(struct sock sk, struct msghdr msg, size_t len)
		int mss_now = 0, size_goal = 0, ret = 0;
		struct mptcp_sock *msk = mptcp_sk(sk);
		struct page_frag *pfrag;
		struct socket *ssock;
		size_t copied = 0;
		struct sock *ssk;
		bool tx_ok;
		@@ -759,15 +774,6 @@ static int mptcp_sendmsg(struct sock sk, struct msghdr msg, size_t len)
		goto out;
		}

		fallback:
		ssock = __mptcp_tcp_fallback(msk);
		if (unlikely(ssock)) {
		release_sock(sk);
		pr_debug("fallback passthrough");
		ret = sock_sendmsg(ssock, msg);
		return ret >= 0 ? ret + copied : (copied ? copied : ret);
		}

		pfrag = sk_page_frag(sk);
		restart:
		mptcp_clean_una(sk);
		@@ -819,17 +825,6 @@ wait_for_sndbuf:
		}
		break;
		}
		if (ret == 0 && unlikely(__mptcp_needs_tcp_fallback(msk))) {
		/* Can happen for passive sockets:
		* 3WHS negotiated MPTCP, but first packet after is
		* plain TCP (e.g. due to middlebox filtering unknown
		* options).
		*
		* Fall back to TCP.
		*/
		release_sock(ssk);
		goto fallback;
		}

		copied += ret;

		@@ -972,7 +967,6 @@ static int mptcp_recvmsg(struct sock sk, struct msghdr msg, size_t len,
		int nonblock, int flags, int *addr_len)
		{
		struct mptcp_sock *msk = mptcp_sk(sk);
		struct socket *ssock;
		int copied = 0;
		int target;
		long timeo;
		@@ -981,16 +975,6 @@ static int mptcp_recvmsg(struct sock sk, struct msghdr msg, size_t len,
		return -EOPNOTSUPP;

		lock_sock(sk);
		ssock = __mptcp_tcp_fallback(msk);
		if (unlikely(ssock)) {
		fallback:
		release_sock(sk);
		pr_debug("fallback-read subflow=%p",
		mptcp_subflow_ctx(ssock->sk));
		copied = sock_recvmsg(ssock, msg, flags);
		return copied;
		}

		timeo = sock_rcvtimeo(sk, nonblock);

		len = min_t(size_t, len, INT_MAX);
		@@ -1056,9 +1040,6 @@ fallback:

		pr_debug("block timeout %ld", timeo);
		mptcp_wait_data(sk, &timeo);
		ssock = __mptcp_tcp_fallback(msk);
		if (unlikely(ssock))
		goto fallback;
		}

		if (skb_queue_empty(&sk->sk_receive_queue)) {
		@@ -1335,8 +1316,6 @@ static void mptcp_subflow_shutdown(struct sock *ssk, int how,
		break;
		}

		/* Wake up anyone sleeping in poll. */
		ssk->sk_state_change(ssk);
		release_sock(ssk);
		}

		@@ -1660,12 +1639,6 @@ void mptcp_finish_connect(struct sock *ssk)
		sk = subflow->conn;
		msk = mptcp_sk(sk);

		if (!subflow->mp_capable) {
		MPTCP_INC_STATS(sock_net(sk),
		MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
		return;
		}

		pr_debug("msk=%p, token=%u", sk, subflow->token);

		mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
		@@ -1971,23 +1944,10 @@ static __poll_t mptcp_poll(struct file file, struct socket sock,
		{
		struct sock *sk = sock->sk;
		struct mptcp_sock *msk;
		struct socket *ssock;
		__poll_t mask = 0;

		msk = mptcp_sk(sk);
		lock_sock(sk);
		ssock = __mptcp_tcp_fallback(msk);
		if (!ssock)
		ssock = __mptcp_nmpc_socket(msk);
		if (ssock) {
		mask = ssock->ops->poll(file, ssock, wait);
		release_sock(sk);
		return mask;
		}

		release_sock(sk);
		sock_poll_wait(file, sock, wait);
		lock_sock(sk);

		if (test_bit(MPTCP_DATA_READY, &msk->flags))
		mask = EPOLLIN \| EPOLLRDNORM;
		@@ -1997,8 +1957,6 @@ static __poll_t mptcp_poll(struct file file, struct socket sock,
		if (sk->sk_shutdown & RCV_SHUTDOWN)
		mask \|= EPOLLIN \| EPOLLRDNORM \| EPOLLRDHUP;

		release_sock(sk);

		return mask;
		}

		@@ -2006,18 +1964,11 @@ static int mptcp_shutdown(struct socket *sock, int how)
		{
		struct mptcp_sock *msk = mptcp_sk(sock->sk);
		struct mptcp_subflow_context *subflow;
		struct socket *ssock;
		int ret = 0;

		pr_debug("sk=%p, how=%d", msk, how);

		lock_sock(sock->sk);
		ssock = __mptcp_tcp_fallback(msk);
		if (ssock) {
		release_sock(sock->sk);
		return inet_shutdown(ssock, how);
		}

		if (how == SHUT_WR \|\| how == SHUT_RDWR)
		inet_sk_state_store(sock->sk, TCP_FIN_WAIT1);

		@@ -2043,6 +1994,9 @@ static int mptcp_shutdown(struct socket *sock, int how)
		mptcp_subflow_shutdown(tcp_sk, how, 1, msk->write_seq);
		}

		/* Wake up anyone sleeping in poll. */
		sock->sk->sk_state_change(sock->sk);

		out_unlock:
		release_sock(sock->sk);

net/mptcp/protocol.h

+33 −0

Original line number	Diff line number	Diff line
		@@ -89,6 +89,7 @@
		#define MPTCP_SEND_SPACE 1
		#define MPTCP_WORK_RTX 2
		#define MPTCP_WORK_EOF 3
		#define MPTCP_FALLBACK_DONE 4

		struct mptcp_options_received {
		u64 sndr_key;
		@@ -457,4 +458,36 @@ static inline bool before64(__u64 seq1, __u64 seq2)

		void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);

		static inline bool __mptcp_check_fallback(struct mptcp_sock *msk)
		{
		return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
		}

		static inline bool mptcp_check_fallback(struct sock *sk)
		{
		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
		struct mptcp_sock *msk = mptcp_sk(subflow->conn);

		return __mptcp_check_fallback(msk);
		}

		static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
		{
		if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
		pr_debug("TCP fallback already done (msk=%p)", msk);
		return;
		}
		set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
		}

		static inline void mptcp_do_fallback(struct sock *sk)
		{
		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
		struct mptcp_sock *msk = mptcp_sk(subflow->conn);

		__mptcp_do_fallback(msk);
		}

		#define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)

		#endif /* __MPTCP_PROTOCOL_H */

net/mptcp/subflow.c

+31 −16

Original line number	Diff line number	Diff line
		@@ -216,7 +216,6 @@ static void subflow_finish_connect(struct sock sk, const struct sk_buff skb)
		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
		struct mptcp_options_received mp_opt;
		struct sock *parent = subflow->conn;
		struct tcp_sock *tp = tcp_sk(sk);

		subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);

		@@ -230,6 +229,8 @@ static void subflow_finish_connect(struct sock sk, const struct sk_buff skb)
		return;

		subflow->conn_finished = 1;
		subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
		pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset);

		mptcp_get_options(skb, &mp_opt);
		if (subflow->request_mptcp && mp_opt.mp_capable) {
		@@ -245,21 +246,20 @@ static void subflow_finish_connect(struct sock sk, const struct sk_buff skb)
		pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
		subflow->thmac, subflow->remote_nonce);
		} else {
		tp->is_mptcp = 0;
		if (subflow->request_mptcp)
		MPTCP_INC_STATS(sock_net(sk),
		MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
		mptcp_do_fallback(sk);
		pr_fallback(mptcp_sk(subflow->conn));
		}

		if (!tp->is_mptcp)
		if (mptcp_check_fallback(sk))
		return;

		if (subflow->mp_capable) {
		pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk),
		subflow->remote_key);
		mptcp_finish_connect(sk);

		if (skb) {
		pr_debug("synack seq=%u", TCP_SKB_CB(skb)->seq);
		subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
		}
		} else if (subflow->mp_join) {
		u8 hmac[SHA256_DIGEST_SIZE];

		@@ -279,9 +279,6 @@ static void subflow_finish_connect(struct sock sk, const struct sk_buff skb)

		memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN);

		if (skb)
		subflow->ssn_offset = TCP_SKB_CB(skb)->seq;

		if (!mptcp_finish_join(sk))
		goto do_reset;

		@@ -557,7 +554,8 @@ enum mapping_status {
		MAPPING_OK,
		MAPPING_INVALID,
		MAPPING_EMPTY,
		MAPPING_DATA_FIN
		MAPPING_DATA_FIN,
		MAPPING_DUMMY
		};

		static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq)
		@@ -621,6 +619,9 @@ static enum mapping_status get_mapping_status(struct sock *ssk)
		if (!skb)
		return MAPPING_EMPTY;

		if (mptcp_check_fallback(ssk))
		return MAPPING_DUMMY;

		mpext = mptcp_get_ext(skb);
		if (!mpext \|\| !mpext->use_map) {
		if (!subflow->map_valid && !skb->len) {
		@@ -762,6 +763,16 @@ static bool subflow_check_data_avail(struct sock *ssk)
		ssk->sk_err = EBADMSG;
		goto fatal;
		}
		if (status == MAPPING_DUMMY) {
		__mptcp_do_fallback(msk);
		skb = skb_peek(&ssk->sk_receive_queue);
		subflow->map_valid = 1;
		subflow->map_seq = READ_ONCE(msk->ack_seq);
		subflow->map_data_len = skb->len;
		subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq -
		subflow->ssn_offset;
		return true;
		}

		if (status != MAPPING_OK)
		return false;
		@@ -885,14 +896,18 @@ static void subflow_data_ready(struct sock *sk)
		{
		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
		struct sock *parent = subflow->conn;
		struct mptcp_sock *msk;

		if (!subflow->mp_capable && !subflow->mp_join) {
		subflow->tcp_data_ready(sk);

		msk = mptcp_sk(parent);
		if (inet_sk_state_load(sk) == TCP_LISTEN) {
		set_bit(MPTCP_DATA_READY, &msk->flags);
		parent->sk_data_ready(parent);
		return;
		}

		WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable &&
		!subflow->mp_join);

		if (mptcp_subflow_data_available(sk))
		mptcp_data_ready(parent, sk);
		}
		@@ -1117,7 +1132,7 @@ static void subflow_state_change(struct sock *sk)
		* a fin packet carrying a DSS can be unnoticed if we don't trigger
		* the data available machinery here.
		*/
		if (subflow->mp_capable && mptcp_subflow_data_available(sk))
		if (mptcp_subflow_data_available(sk))
		mptcp_data_ready(parent, sk);

		if (!(parent->sk_shutdown & RCV_SHUTDOWN) &&

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