Commit 648ef4b8 authored by Mat Martineau's avatar Mat Martineau Committed by David S. Miller
Browse files

mptcp: Implement MPTCP receive path 



Parses incoming DSS options and populates outgoing MPTCP ACK
fields. MPTCP fields are parsed from the TCP option header and placed in
an skb extension, allowing the upper MPTCP layer to access MPTCP
options after the skb has gone through the TCP stack.

The subflow implements its own data_ready() ops, which ensures that the
pending data is in sequence - according to MPTCP seq number - dropping
out-of-seq skbs. The DATA_READY bit flag is set if this is the case.
This allows the MPTCP socket layer to determine if more data is
available without having to consult the individual subflows.

It additionally validates the current mapping and propagates EoF events
to the connection socket.

Co-developed-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Co-developed-by: default avatarPeter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: default avatarPeter Krystad <peter.krystad@linux.intel.com>
Co-developed-by: default avatarDavide Caratti <dcaratti@redhat.com>
Signed-off-by: default avatarDavide Caratti <dcaratti@redhat.com>
Co-developed-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarChristoph Paasch <cpaasch@apple.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6d0060f6

include/linux/tcp.h

+10 −0
Original line number Diff line number Diff line
@@ -82,9 +82,19 @@ struct tcp_sack_block { 
struct mptcp_options_received {

	u64	sndr_key;

	u64	rcvr_key;

	u64	data_ack;

	u64	data_seq;

	u32	subflow_seq;

	u16	data_len;

	u8	mp_capable : 1,

		mp_join : 1,

		dss : 1;

	u8	use_map:1,

		dsn64:1,

		data_fin:1,

		use_ack:1,

		ack64:1,

		__unused:3;

};

#endif

include/net/mptcp.h

+8 −0
Original line number Diff line number Diff line
@@ -60,6 +60,8 @@ bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, 
bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,

			       unsigned int *size, unsigned int remaining,

			       struct mptcp_out_options *opts);

void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb,

			    struct tcp_options_received *opt_rx);



void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts);
@@ -150,6 +152,12 @@ static inline bool mptcp_established_options(struct sock *sk, 
	return false;

}



static inline void mptcp_incoming_options(struct sock *sk,

					  struct sk_buff *skb,

					  struct tcp_options_received *opt_rx)

{

}



static inline void mptcp_skb_ext_move(struct sk_buff *to,

				      const struct sk_buff *from)

{

net/ipv4/tcp_input.c

+7 −1
Original line number Diff line number Diff line
@@ -4770,6 +4770,9 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 
	bool fragstolen;

	int eaten;



	if (sk_is_mptcp(sk))

		mptcp_incoming_options(sk, skb, &tp->rx_opt);



	if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {

		__kfree_skb(skb);

		return;
@@ -6346,8 +6349,11 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) 
	case TCP_CLOSE_WAIT:

	case TCP_CLOSING:

	case TCP_LAST_ACK:

		if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt))

		if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {

			if (sk_is_mptcp(sk))

				mptcp_incoming_options(sk, skb, &tp->rx_opt);

			break;

		}

		/* fall through */

	case TCP_FIN_WAIT1:

	case TCP_FIN_WAIT2:

net/mptcp/options.c

+107 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ void mptcp_parse_option(const unsigned char *ptr, int opsize, 
{

	struct mptcp_options_received *mp_opt = &opt_rx->mptcp;

	u8 subtype = *ptr >> 4;

	int expected_opsize;

	u8 version;

	u8 flags;
@@ -64,7 +65,79 @@ void mptcp_parse_option(const unsigned char *ptr, int opsize, 


	case MPTCPOPT_DSS:

		pr_debug("DSS");

		ptr++;



		flags = (*ptr++) & MPTCP_DSS_FLAG_MASK;

		mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0;

		mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0;

		mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0;

		mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0;

		mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK);



		pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d",

			 mp_opt->data_fin, mp_opt->dsn64,

			 mp_opt->use_map, mp_opt->ack64,

			 mp_opt->use_ack);



		expected_opsize = TCPOLEN_MPTCP_DSS_BASE;



		if (mp_opt->use_ack) {

			if (mp_opt->ack64)

				expected_opsize += TCPOLEN_MPTCP_DSS_ACK64;

			else

				expected_opsize += TCPOLEN_MPTCP_DSS_ACK32;

		}



		if (mp_opt->use_map) {

			if (mp_opt->dsn64)

				expected_opsize += TCPOLEN_MPTCP_DSS_MAP64;

			else

				expected_opsize += TCPOLEN_MPTCP_DSS_MAP32;

		}



		/* RFC 6824, Section 3.3:

		 * If a checksum is present, but its use had

		 * not been negotiated in the MP_CAPABLE handshake,

		 * the checksum field MUST be ignored.

		 */

		if (opsize != expected_opsize &&

		    opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM)

			break;



		mp_opt->dss = 1;



		if (mp_opt->use_ack) {

			if (mp_opt->ack64) {

				mp_opt->data_ack = get_unaligned_be64(ptr);

				ptr += 8;

			} else {

				mp_opt->data_ack = get_unaligned_be32(ptr);

				ptr += 4;

			}



			pr_debug("data_ack=%llu", mp_opt->data_ack);

		}



		if (mp_opt->use_map) {

			if (mp_opt->dsn64) {

				mp_opt->data_seq = get_unaligned_be64(ptr);

				ptr += 8;

			} else {

				mp_opt->data_seq = get_unaligned_be32(ptr);

				ptr += 4;

			}



			mp_opt->subflow_seq = get_unaligned_be32(ptr);

			ptr += 4;



			mp_opt->data_len = get_unaligned_be16(ptr);

			ptr += 2;



			pr_debug("data_seq=%llu subflow_seq=%u data_len=%u",

				 mp_opt->data_seq, mp_opt->subflow_seq,

				 mp_opt->data_len);

		}



		break;



	default:
@@ -275,6 +348,40 @@ bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, 
	return false;

}



void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb,

			    struct tcp_options_received *opt_rx)

{

	struct mptcp_options_received *mp_opt;

	struct mptcp_ext *mpext;



	mp_opt = &opt_rx->mptcp;



	if (!mp_opt->dss)

		return;



	mpext = skb_ext_add(skb, SKB_EXT_MPTCP);

	if (!mpext)

		return;



	memset(mpext, 0, sizeof(*mpext));



	if (mp_opt->use_map) {

		mpext->data_seq = mp_opt->data_seq;

		mpext->subflow_seq = mp_opt->subflow_seq;

		mpext->data_len = mp_opt->data_len;

		mpext->use_map = 1;

		mpext->dsn64 = mp_opt->dsn64;

	}



	if (mp_opt->use_ack) {

		mpext->data_ack = mp_opt->data_ack;

		mpext->use_ack = 1;

		mpext->ack64 = mp_opt->ack64;

	}



	mpext->data_fin = mp_opt->data_fin;

}



void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)

{

	if ((OPTION_MPTCP_MPC_SYN |

net/mptcp/protocol.c

+34 −0
Original line number Diff line number Diff line
@@ -224,6 +224,33 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
	return ret;

}



int mptcp_read_actor(read_descriptor_t *desc, struct sk_buff *skb,

		     unsigned int offset, size_t len)

{

	struct mptcp_read_arg *arg = desc->arg.data;

	size_t copy_len;



	copy_len = min(desc->count, len);



	if (likely(arg->msg)) {

		int err;



		err = skb_copy_datagram_msg(skb, offset, arg->msg, copy_len);

		if (err) {

			pr_debug("error path");

			desc->error = err;

			return err;

		}

	} else {

		pr_debug("Flushing skb payload");

	}



	desc->count -= copy_len;



	pr_debug("consumed %zu bytes, %zu left", copy_len, desc->count);

	return copy_len;

}



static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,

			 int nonblock, int flags, int *addr_len)

{
@@ -414,7 +441,10 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, 
		msk->write_seq = subflow->idsn + 1;

		ack_seq++;

		msk->ack_seq = ack_seq;

		subflow->map_seq = ack_seq;

		subflow->map_subflow_seq = 1;

		subflow->rel_write_seq = 1;

		subflow->tcp_sock = ssk;

		newsk = new_mptcp_sock;

		mptcp_copy_inaddrs(newsk, ssk);

		list_add(&subflow->node, &msk->conn_list);
@@ -519,8 +549,12 @@ void mptcp_finish_connect(struct sock *ssk) 
	sk = subflow->conn;

	msk = mptcp_sk(sk);



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



	mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);

	ack_seq++;

	subflow->map_seq = ack_seq;

	subflow->map_subflow_seq = 1;

	subflow->rel_write_seq = 1;



	/* the socket is not connected yet, no msk/subflow ops can access/race

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