xref: /openbmc/linux/net/mptcp/protocol.c (revision d22f4988ffecbe284e4d00e897525adbd0edd801)
1f870fa0bSMat Martineau // SPDX-License-Identifier: GPL-2.0
2f870fa0bSMat Martineau /* Multipath TCP
3f870fa0bSMat Martineau  *
4f870fa0bSMat Martineau  * Copyright (c) 2017 - 2019, Intel Corporation.
5f870fa0bSMat Martineau  */
6f870fa0bSMat Martineau 
7f870fa0bSMat Martineau #define pr_fmt(fmt) "MPTCP: " fmt
8f870fa0bSMat Martineau 
9f870fa0bSMat Martineau #include <linux/kernel.h>
10f870fa0bSMat Martineau #include <linux/module.h>
11f870fa0bSMat Martineau #include <linux/netdevice.h>
127a6a6cbcSPaolo Abeni #include <linux/sched/signal.h>
137a6a6cbcSPaolo Abeni #include <linux/atomic.h>
14f870fa0bSMat Martineau #include <net/sock.h>
15f870fa0bSMat Martineau #include <net/inet_common.h>
16f870fa0bSMat Martineau #include <net/inet_hashtables.h>
17f870fa0bSMat Martineau #include <net/protocol.h>
18f870fa0bSMat Martineau #include <net/tcp.h>
19cf7da0d6SPeter Krystad #if IS_ENABLED(CONFIG_MPTCP_IPV6)
20cf7da0d6SPeter Krystad #include <net/transp_v6.h>
21cf7da0d6SPeter Krystad #endif
22f870fa0bSMat Martineau #include <net/mptcp.h>
23f870fa0bSMat Martineau #include "protocol.h"
24f870fa0bSMat Martineau 
252303f994SPeter Krystad #define MPTCP_SAME_STATE TCP_MAX_STATES
262303f994SPeter Krystad 
272303f994SPeter Krystad /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
282303f994SPeter Krystad  * completed yet or has failed, return the subflow socket.
292303f994SPeter Krystad  * Otherwise return NULL.
302303f994SPeter Krystad  */
312303f994SPeter Krystad static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
322303f994SPeter Krystad {
33*d22f4988SChristoph Paasch 	if (!msk->subflow || READ_ONCE(msk->can_ack))
342303f994SPeter Krystad 		return NULL;
352303f994SPeter Krystad 
362303f994SPeter Krystad 	return msk->subflow;
372303f994SPeter Krystad }
382303f994SPeter Krystad 
39cec37a6eSPeter Krystad /* if msk has a single subflow, and the mp_capable handshake is failed,
40cec37a6eSPeter Krystad  * return it.
41cec37a6eSPeter Krystad  * Otherwise returns NULL
42cec37a6eSPeter Krystad  */
43cec37a6eSPeter Krystad static struct socket *__mptcp_tcp_fallback(const struct mptcp_sock *msk)
44cec37a6eSPeter Krystad {
45cec37a6eSPeter Krystad 	struct socket *ssock = __mptcp_nmpc_socket(msk);
46cec37a6eSPeter Krystad 
47cec37a6eSPeter Krystad 	sock_owned_by_me((const struct sock *)msk);
48cec37a6eSPeter Krystad 
49cec37a6eSPeter Krystad 	if (!ssock || sk_is_mptcp(ssock->sk))
50cec37a6eSPeter Krystad 		return NULL;
51cec37a6eSPeter Krystad 
52cec37a6eSPeter Krystad 	return ssock;
53cec37a6eSPeter Krystad }
54cec37a6eSPeter Krystad 
552303f994SPeter Krystad static bool __mptcp_can_create_subflow(const struct mptcp_sock *msk)
562303f994SPeter Krystad {
572303f994SPeter Krystad 	return ((struct sock *)msk)->sk_state == TCP_CLOSE;
582303f994SPeter Krystad }
592303f994SPeter Krystad 
602303f994SPeter Krystad static struct socket *__mptcp_socket_create(struct mptcp_sock *msk, int state)
612303f994SPeter Krystad {
622303f994SPeter Krystad 	struct mptcp_subflow_context *subflow;
632303f994SPeter Krystad 	struct sock *sk = (struct sock *)msk;
642303f994SPeter Krystad 	struct socket *ssock;
652303f994SPeter Krystad 	int err;
662303f994SPeter Krystad 
672303f994SPeter Krystad 	ssock = __mptcp_nmpc_socket(msk);
682303f994SPeter Krystad 	if (ssock)
692303f994SPeter Krystad 		goto set_state;
702303f994SPeter Krystad 
712303f994SPeter Krystad 	if (!__mptcp_can_create_subflow(msk))
722303f994SPeter Krystad 		return ERR_PTR(-EINVAL);
732303f994SPeter Krystad 
742303f994SPeter Krystad 	err = mptcp_subflow_create_socket(sk, &ssock);
752303f994SPeter Krystad 	if (err)
762303f994SPeter Krystad 		return ERR_PTR(err);
772303f994SPeter Krystad 
782303f994SPeter Krystad 	msk->subflow = ssock;
792303f994SPeter Krystad 	subflow = mptcp_subflow_ctx(ssock->sk);
80cec37a6eSPeter Krystad 	list_add(&subflow->node, &msk->conn_list);
812303f994SPeter Krystad 	subflow->request_mptcp = 1;
822303f994SPeter Krystad 
832303f994SPeter Krystad set_state:
842303f994SPeter Krystad 	if (state != MPTCP_SAME_STATE)
852303f994SPeter Krystad 		inet_sk_state_store(sk, state);
862303f994SPeter Krystad 	return ssock;
872303f994SPeter Krystad }
882303f994SPeter Krystad 
89cec37a6eSPeter Krystad static struct sock *mptcp_subflow_get(const struct mptcp_sock *msk)
90cec37a6eSPeter Krystad {
91cec37a6eSPeter Krystad 	struct mptcp_subflow_context *subflow;
92cec37a6eSPeter Krystad 
93cec37a6eSPeter Krystad 	sock_owned_by_me((const struct sock *)msk);
94cec37a6eSPeter Krystad 
95cec37a6eSPeter Krystad 	mptcp_for_each_subflow(msk, subflow) {
96cec37a6eSPeter Krystad 		return mptcp_subflow_tcp_sock(subflow);
97cec37a6eSPeter Krystad 	}
98cec37a6eSPeter Krystad 
99cec37a6eSPeter Krystad 	return NULL;
100cec37a6eSPeter Krystad }
101cec37a6eSPeter Krystad 
1026d0060f6SMat Martineau static bool mptcp_ext_cache_refill(struct mptcp_sock *msk)
1036d0060f6SMat Martineau {
1046d0060f6SMat Martineau 	if (!msk->cached_ext)
1056d0060f6SMat Martineau 		msk->cached_ext = __skb_ext_alloc();
1066d0060f6SMat Martineau 
1076d0060f6SMat Martineau 	return !!msk->cached_ext;
1086d0060f6SMat Martineau }
1096d0060f6SMat Martineau 
1107a6a6cbcSPaolo Abeni static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
1117a6a6cbcSPaolo Abeni {
1127a6a6cbcSPaolo Abeni 	struct mptcp_subflow_context *subflow;
1137a6a6cbcSPaolo Abeni 	struct sock *sk = (struct sock *)msk;
1147a6a6cbcSPaolo Abeni 
1157a6a6cbcSPaolo Abeni 	sock_owned_by_me(sk);
1167a6a6cbcSPaolo Abeni 
1177a6a6cbcSPaolo Abeni 	mptcp_for_each_subflow(msk, subflow) {
1187a6a6cbcSPaolo Abeni 		if (subflow->data_avail)
1197a6a6cbcSPaolo Abeni 			return mptcp_subflow_tcp_sock(subflow);
1207a6a6cbcSPaolo Abeni 	}
1217a6a6cbcSPaolo Abeni 
1227a6a6cbcSPaolo Abeni 	return NULL;
1237a6a6cbcSPaolo Abeni }
1247a6a6cbcSPaolo Abeni 
12557040755SPaolo Abeni static inline bool mptcp_skb_can_collapse_to(const struct mptcp_sock *msk,
12657040755SPaolo Abeni 					     const struct sk_buff *skb,
12757040755SPaolo Abeni 					     const struct mptcp_ext *mpext)
1286d0060f6SMat Martineau {
12957040755SPaolo Abeni 	if (!tcp_skb_can_collapse_to(skb))
13057040755SPaolo Abeni 		return false;
13157040755SPaolo Abeni 
13257040755SPaolo Abeni 	/* can collapse only if MPTCP level sequence is in order */
13357040755SPaolo Abeni 	return mpext && mpext->data_seq + mpext->data_len == msk->write_seq;
13457040755SPaolo Abeni }
13557040755SPaolo Abeni 
13657040755SPaolo Abeni static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
13757040755SPaolo Abeni 			      struct msghdr *msg, long *timeo, int *pmss_now,
13857040755SPaolo Abeni 			      int *ps_goal)
13957040755SPaolo Abeni {
14057040755SPaolo Abeni 	int mss_now, avail_size, size_goal, ret;
1416d0060f6SMat Martineau 	struct mptcp_sock *msk = mptcp_sk(sk);
1426d0060f6SMat Martineau 	struct mptcp_ext *mpext = NULL;
14357040755SPaolo Abeni 	struct sk_buff *skb, *tail;
14457040755SPaolo Abeni 	bool can_collapse = false;
1456d0060f6SMat Martineau 	struct page_frag *pfrag;
1466d0060f6SMat Martineau 	size_t psize;
1476d0060f6SMat Martineau 
1486d0060f6SMat Martineau 	/* use the mptcp page cache so that we can easily move the data
1496d0060f6SMat Martineau 	 * from one substream to another, but do per subflow memory accounting
1506d0060f6SMat Martineau 	 */
1516d0060f6SMat Martineau 	pfrag = sk_page_frag(sk);
1526d0060f6SMat Martineau 	while (!sk_page_frag_refill(ssk, pfrag) ||
1536d0060f6SMat Martineau 	       !mptcp_ext_cache_refill(msk)) {
1546d0060f6SMat Martineau 		ret = sk_stream_wait_memory(ssk, timeo);
1556d0060f6SMat Martineau 		if (ret)
1566d0060f6SMat Martineau 			return ret;
1576d0060f6SMat Martineau 	}
1586d0060f6SMat Martineau 
1596d0060f6SMat Martineau 	/* compute copy limit */
1606d0060f6SMat Martineau 	mss_now = tcp_send_mss(ssk, &size_goal, msg->msg_flags);
16157040755SPaolo Abeni 	*pmss_now = mss_now;
16257040755SPaolo Abeni 	*ps_goal = size_goal;
16357040755SPaolo Abeni 	avail_size = size_goal;
16457040755SPaolo Abeni 	skb = tcp_write_queue_tail(ssk);
16557040755SPaolo Abeni 	if (skb) {
16657040755SPaolo Abeni 		mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
1676d0060f6SMat Martineau 
16857040755SPaolo Abeni 		/* Limit the write to the size available in the
16957040755SPaolo Abeni 		 * current skb, if any, so that we create at most a new skb.
17057040755SPaolo Abeni 		 * Explicitly tells TCP internals to avoid collapsing on later
17157040755SPaolo Abeni 		 * queue management operation, to avoid breaking the ext <->
17257040755SPaolo Abeni 		 * SSN association set here
17357040755SPaolo Abeni 		 */
17457040755SPaolo Abeni 		can_collapse = (size_goal - skb->len > 0) &&
17557040755SPaolo Abeni 			      mptcp_skb_can_collapse_to(msk, skb, mpext);
17657040755SPaolo Abeni 		if (!can_collapse)
17757040755SPaolo Abeni 			TCP_SKB_CB(skb)->eor = 1;
17857040755SPaolo Abeni 		else
17957040755SPaolo Abeni 			avail_size = size_goal - skb->len;
18057040755SPaolo Abeni 	}
18157040755SPaolo Abeni 	psize = min_t(size_t, pfrag->size - pfrag->offset, avail_size);
18257040755SPaolo Abeni 
18357040755SPaolo Abeni 	/* Copy to page */
1846d0060f6SMat Martineau 	pr_debug("left=%zu", msg_data_left(msg));
1856d0060f6SMat Martineau 	psize = copy_page_from_iter(pfrag->page, pfrag->offset,
1866d0060f6SMat Martineau 				    min_t(size_t, msg_data_left(msg), psize),
1876d0060f6SMat Martineau 				    &msg->msg_iter);
1886d0060f6SMat Martineau 	pr_debug("left=%zu", msg_data_left(msg));
1896d0060f6SMat Martineau 	if (!psize)
1906d0060f6SMat Martineau 		return -EINVAL;
1916d0060f6SMat Martineau 
19257040755SPaolo Abeni 	/* tell the TCP stack to delay the push so that we can safely
19357040755SPaolo Abeni 	 * access the skb after the sendpages call
1946d0060f6SMat Martineau 	 */
1956d0060f6SMat Martineau 	ret = do_tcp_sendpages(ssk, pfrag->page, pfrag->offset, psize,
1966d0060f6SMat Martineau 			       msg->msg_flags | MSG_SENDPAGE_NOTLAST);
1976d0060f6SMat Martineau 	if (ret <= 0)
1986d0060f6SMat Martineau 		return ret;
1996d0060f6SMat Martineau 	if (unlikely(ret < psize))
2006d0060f6SMat Martineau 		iov_iter_revert(&msg->msg_iter, psize - ret);
2016d0060f6SMat Martineau 
20257040755SPaolo Abeni 	/* if the tail skb extension is still the cached one, collapsing
20357040755SPaolo Abeni 	 * really happened. Note: we can't check for 'same skb' as the sk_buff
20457040755SPaolo Abeni 	 * hdr on tail can be transmitted, freed and re-allocated by the
20557040755SPaolo Abeni 	 * do_tcp_sendpages() call
20657040755SPaolo Abeni 	 */
20757040755SPaolo Abeni 	tail = tcp_write_queue_tail(ssk);
20857040755SPaolo Abeni 	if (mpext && tail && mpext == skb_ext_find(tail, SKB_EXT_MPTCP)) {
20957040755SPaolo Abeni 		WARN_ON_ONCE(!can_collapse);
21057040755SPaolo Abeni 		mpext->data_len += ret;
21157040755SPaolo Abeni 		goto out;
21257040755SPaolo Abeni 	}
21357040755SPaolo Abeni 
2146d0060f6SMat Martineau 	skb = tcp_write_queue_tail(ssk);
2156d0060f6SMat Martineau 	mpext = __skb_ext_set(skb, SKB_EXT_MPTCP, msk->cached_ext);
2166d0060f6SMat Martineau 	msk->cached_ext = NULL;
2176d0060f6SMat Martineau 
2186d0060f6SMat Martineau 	memset(mpext, 0, sizeof(*mpext));
2196d0060f6SMat Martineau 	mpext->data_seq = msk->write_seq;
2206d0060f6SMat Martineau 	mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
2216d0060f6SMat Martineau 	mpext->data_len = ret;
2226d0060f6SMat Martineau 	mpext->use_map = 1;
2236d0060f6SMat Martineau 	mpext->dsn64 = 1;
2246d0060f6SMat Martineau 
2256d0060f6SMat Martineau 	pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
2266d0060f6SMat Martineau 		 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
2276d0060f6SMat Martineau 		 mpext->dsn64);
2286d0060f6SMat Martineau 
22957040755SPaolo Abeni out:
2306d0060f6SMat Martineau 	pfrag->offset += ret;
2316d0060f6SMat Martineau 	msk->write_seq += ret;
2326d0060f6SMat Martineau 	mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
2336d0060f6SMat Martineau 
2346d0060f6SMat Martineau 	return ret;
2356d0060f6SMat Martineau }
2366d0060f6SMat Martineau 
2371891c4a0SFlorian Westphal static void ssk_check_wmem(struct mptcp_sock *msk, struct sock *ssk)
2381891c4a0SFlorian Westphal {
2391891c4a0SFlorian Westphal 	struct socket *sock;
2401891c4a0SFlorian Westphal 
2411891c4a0SFlorian Westphal 	if (likely(sk_stream_is_writeable(ssk)))
2421891c4a0SFlorian Westphal 		return;
2431891c4a0SFlorian Westphal 
2441891c4a0SFlorian Westphal 	sock = READ_ONCE(ssk->sk_socket);
2451891c4a0SFlorian Westphal 
2461891c4a0SFlorian Westphal 	if (sock) {
2471891c4a0SFlorian Westphal 		clear_bit(MPTCP_SEND_SPACE, &msk->flags);
2481891c4a0SFlorian Westphal 		smp_mb__after_atomic();
2491891c4a0SFlorian Westphal 		/* set NOSPACE only after clearing SEND_SPACE flag */
2501891c4a0SFlorian Westphal 		set_bit(SOCK_NOSPACE, &sock->flags);
2511891c4a0SFlorian Westphal 	}
2521891c4a0SFlorian Westphal }
2531891c4a0SFlorian Westphal 
254f870fa0bSMat Martineau static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
255f870fa0bSMat Martineau {
25657040755SPaolo Abeni 	int mss_now = 0, size_goal = 0, ret = 0;
257f870fa0bSMat Martineau 	struct mptcp_sock *msk = mptcp_sk(sk);
258cec37a6eSPeter Krystad 	struct socket *ssock;
2596d0060f6SMat Martineau 	size_t copied = 0;
260cec37a6eSPeter Krystad 	struct sock *ssk;
2616d0060f6SMat Martineau 	long timeo;
262f870fa0bSMat Martineau 
263f870fa0bSMat Martineau 	if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))
264f870fa0bSMat Martineau 		return -EOPNOTSUPP;
265f870fa0bSMat Martineau 
266cec37a6eSPeter Krystad 	lock_sock(sk);
267cec37a6eSPeter Krystad 	ssock = __mptcp_tcp_fallback(msk);
268cec37a6eSPeter Krystad 	if (ssock) {
269cec37a6eSPeter Krystad 		pr_debug("fallback passthrough");
270cec37a6eSPeter Krystad 		ret = sock_sendmsg(ssock, msg);
271cec37a6eSPeter Krystad 		release_sock(sk);
272cec37a6eSPeter Krystad 		return ret;
273cec37a6eSPeter Krystad 	}
274cec37a6eSPeter Krystad 
2756d0060f6SMat Martineau 	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
2766d0060f6SMat Martineau 
277cec37a6eSPeter Krystad 	ssk = mptcp_subflow_get(msk);
278cec37a6eSPeter Krystad 	if (!ssk) {
279cec37a6eSPeter Krystad 		release_sock(sk);
280cec37a6eSPeter Krystad 		return -ENOTCONN;
281cec37a6eSPeter Krystad 	}
282cec37a6eSPeter Krystad 
2836d0060f6SMat Martineau 	pr_debug("conn_list->subflow=%p", ssk);
284cec37a6eSPeter Krystad 
2856d0060f6SMat Martineau 	lock_sock(ssk);
2866d0060f6SMat Martineau 	while (msg_data_left(msg)) {
28757040755SPaolo Abeni 		ret = mptcp_sendmsg_frag(sk, ssk, msg, &timeo, &mss_now,
28857040755SPaolo Abeni 					 &size_goal);
2896d0060f6SMat Martineau 		if (ret < 0)
2906d0060f6SMat Martineau 			break;
2916d0060f6SMat Martineau 
2926d0060f6SMat Martineau 		copied += ret;
2936d0060f6SMat Martineau 	}
2946d0060f6SMat Martineau 
29557040755SPaolo Abeni 	if (copied) {
2966d0060f6SMat Martineau 		ret = copied;
29757040755SPaolo Abeni 		tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle,
29857040755SPaolo Abeni 			 size_goal);
29957040755SPaolo Abeni 	}
3006d0060f6SMat Martineau 
3011891c4a0SFlorian Westphal 	ssk_check_wmem(msk, ssk);
3026d0060f6SMat Martineau 	release_sock(ssk);
303cec37a6eSPeter Krystad 	release_sock(sk);
304cec37a6eSPeter Krystad 	return ret;
305f870fa0bSMat Martineau }
306f870fa0bSMat Martineau 
307648ef4b8SMat Martineau int mptcp_read_actor(read_descriptor_t *desc, struct sk_buff *skb,
308648ef4b8SMat Martineau 		     unsigned int offset, size_t len)
309648ef4b8SMat Martineau {
310648ef4b8SMat Martineau 	struct mptcp_read_arg *arg = desc->arg.data;
311648ef4b8SMat Martineau 	size_t copy_len;
312648ef4b8SMat Martineau 
313648ef4b8SMat Martineau 	copy_len = min(desc->count, len);
314648ef4b8SMat Martineau 
315648ef4b8SMat Martineau 	if (likely(arg->msg)) {
316648ef4b8SMat Martineau 		int err;
317648ef4b8SMat Martineau 
318648ef4b8SMat Martineau 		err = skb_copy_datagram_msg(skb, offset, arg->msg, copy_len);
319648ef4b8SMat Martineau 		if (err) {
320648ef4b8SMat Martineau 			pr_debug("error path");
321648ef4b8SMat Martineau 			desc->error = err;
322648ef4b8SMat Martineau 			return err;
323648ef4b8SMat Martineau 		}
324648ef4b8SMat Martineau 	} else {
325648ef4b8SMat Martineau 		pr_debug("Flushing skb payload");
326648ef4b8SMat Martineau 	}
327648ef4b8SMat Martineau 
328648ef4b8SMat Martineau 	desc->count -= copy_len;
329648ef4b8SMat Martineau 
330648ef4b8SMat Martineau 	pr_debug("consumed %zu bytes, %zu left", copy_len, desc->count);
331648ef4b8SMat Martineau 	return copy_len;
332648ef4b8SMat Martineau }
333648ef4b8SMat Martineau 
3347a6a6cbcSPaolo Abeni static void mptcp_wait_data(struct sock *sk, long *timeo)
3357a6a6cbcSPaolo Abeni {
3367a6a6cbcSPaolo Abeni 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
3377a6a6cbcSPaolo Abeni 	struct mptcp_sock *msk = mptcp_sk(sk);
3387a6a6cbcSPaolo Abeni 
3397a6a6cbcSPaolo Abeni 	add_wait_queue(sk_sleep(sk), &wait);
3407a6a6cbcSPaolo Abeni 	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
3417a6a6cbcSPaolo Abeni 
3427a6a6cbcSPaolo Abeni 	sk_wait_event(sk, timeo,
3437a6a6cbcSPaolo Abeni 		      test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait);
3447a6a6cbcSPaolo Abeni 
3457a6a6cbcSPaolo Abeni 	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
3467a6a6cbcSPaolo Abeni 	remove_wait_queue(sk_sleep(sk), &wait);
3477a6a6cbcSPaolo Abeni }
3487a6a6cbcSPaolo Abeni 
349f870fa0bSMat Martineau static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
350f870fa0bSMat Martineau 			 int nonblock, int flags, int *addr_len)
351f870fa0bSMat Martineau {
352f870fa0bSMat Martineau 	struct mptcp_sock *msk = mptcp_sk(sk);
3537a6a6cbcSPaolo Abeni 	struct mptcp_subflow_context *subflow;
3547a6a6cbcSPaolo Abeni 	bool more_data_avail = false;
3557a6a6cbcSPaolo Abeni 	struct mptcp_read_arg arg;
3567a6a6cbcSPaolo Abeni 	read_descriptor_t desc;
3577a6a6cbcSPaolo Abeni 	bool wait_data = false;
358cec37a6eSPeter Krystad 	struct socket *ssock;
3597a6a6cbcSPaolo Abeni 	struct tcp_sock *tp;
3607a6a6cbcSPaolo Abeni 	bool done = false;
361cec37a6eSPeter Krystad 	struct sock *ssk;
362cec37a6eSPeter Krystad 	int copied = 0;
3637a6a6cbcSPaolo Abeni 	int target;
3647a6a6cbcSPaolo Abeni 	long timeo;
365f870fa0bSMat Martineau 
366f870fa0bSMat Martineau 	if (msg->msg_flags & ~(MSG_WAITALL | MSG_DONTWAIT))
367f870fa0bSMat Martineau 		return -EOPNOTSUPP;
368f870fa0bSMat Martineau 
369cec37a6eSPeter Krystad 	lock_sock(sk);
370cec37a6eSPeter Krystad 	ssock = __mptcp_tcp_fallback(msk);
371cec37a6eSPeter Krystad 	if (ssock) {
372cec37a6eSPeter Krystad 		pr_debug("fallback-read subflow=%p",
373cec37a6eSPeter Krystad 			 mptcp_subflow_ctx(ssock->sk));
374cec37a6eSPeter Krystad 		copied = sock_recvmsg(ssock, msg, flags);
375cec37a6eSPeter Krystad 		release_sock(sk);
376cec37a6eSPeter Krystad 		return copied;
377cec37a6eSPeter Krystad 	}
378cec37a6eSPeter Krystad 
3797a6a6cbcSPaolo Abeni 	arg.msg = msg;
3807a6a6cbcSPaolo Abeni 	desc.arg.data = &arg;
3817a6a6cbcSPaolo Abeni 	desc.error = 0;
3827a6a6cbcSPaolo Abeni 
3837a6a6cbcSPaolo Abeni 	timeo = sock_rcvtimeo(sk, nonblock);
3847a6a6cbcSPaolo Abeni 
3857a6a6cbcSPaolo Abeni 	len = min_t(size_t, len, INT_MAX);
3867a6a6cbcSPaolo Abeni 	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
3877a6a6cbcSPaolo Abeni 
3887a6a6cbcSPaolo Abeni 	while (!done) {
3897a6a6cbcSPaolo Abeni 		u32 map_remaining;
3907a6a6cbcSPaolo Abeni 		int bytes_read;
3917a6a6cbcSPaolo Abeni 
3927a6a6cbcSPaolo Abeni 		ssk = mptcp_subflow_recv_lookup(msk);
3937a6a6cbcSPaolo Abeni 		pr_debug("msk=%p ssk=%p", msk, ssk);
3947a6a6cbcSPaolo Abeni 		if (!ssk)
3957a6a6cbcSPaolo Abeni 			goto wait_for_data;
3967a6a6cbcSPaolo Abeni 
3977a6a6cbcSPaolo Abeni 		subflow = mptcp_subflow_ctx(ssk);
3987a6a6cbcSPaolo Abeni 		tp = tcp_sk(ssk);
3997a6a6cbcSPaolo Abeni 
4007a6a6cbcSPaolo Abeni 		lock_sock(ssk);
4017a6a6cbcSPaolo Abeni 		do {
4027a6a6cbcSPaolo Abeni 			/* try to read as much data as available */
4037a6a6cbcSPaolo Abeni 			map_remaining = subflow->map_data_len -
4047a6a6cbcSPaolo Abeni 					mptcp_subflow_get_map_offset(subflow);
4057a6a6cbcSPaolo Abeni 			desc.count = min_t(size_t, len - copied, map_remaining);
4067a6a6cbcSPaolo Abeni 			pr_debug("reading %zu bytes, copied %d", desc.count,
4077a6a6cbcSPaolo Abeni 				 copied);
4087a6a6cbcSPaolo Abeni 			bytes_read = tcp_read_sock(ssk, &desc,
4097a6a6cbcSPaolo Abeni 						   mptcp_read_actor);
4107a6a6cbcSPaolo Abeni 			if (bytes_read < 0) {
4117a6a6cbcSPaolo Abeni 				if (!copied)
4127a6a6cbcSPaolo Abeni 					copied = bytes_read;
4137a6a6cbcSPaolo Abeni 				done = true;
4147a6a6cbcSPaolo Abeni 				goto next;
415cec37a6eSPeter Krystad 			}
416cec37a6eSPeter Krystad 
4177a6a6cbcSPaolo Abeni 			pr_debug("msk ack_seq=%llx -> %llx", msk->ack_seq,
4187a6a6cbcSPaolo Abeni 				 msk->ack_seq + bytes_read);
4197a6a6cbcSPaolo Abeni 			msk->ack_seq += bytes_read;
4207a6a6cbcSPaolo Abeni 			copied += bytes_read;
4217a6a6cbcSPaolo Abeni 			if (copied >= len) {
4227a6a6cbcSPaolo Abeni 				done = true;
4237a6a6cbcSPaolo Abeni 				goto next;
4247a6a6cbcSPaolo Abeni 			}
4257a6a6cbcSPaolo Abeni 			if (tp->urg_data && tp->urg_seq == tp->copied_seq) {
4267a6a6cbcSPaolo Abeni 				pr_err("Urgent data present, cannot proceed");
4277a6a6cbcSPaolo Abeni 				done = true;
4287a6a6cbcSPaolo Abeni 				goto next;
4297a6a6cbcSPaolo Abeni 			}
4307a6a6cbcSPaolo Abeni next:
4317a6a6cbcSPaolo Abeni 			more_data_avail = mptcp_subflow_data_available(ssk);
4327a6a6cbcSPaolo Abeni 		} while (more_data_avail && !done);
4337a6a6cbcSPaolo Abeni 		release_sock(ssk);
4347a6a6cbcSPaolo Abeni 		continue;
4357a6a6cbcSPaolo Abeni 
4367a6a6cbcSPaolo Abeni wait_for_data:
4377a6a6cbcSPaolo Abeni 		more_data_avail = false;
4387a6a6cbcSPaolo Abeni 
4397a6a6cbcSPaolo Abeni 		/* only the master socket status is relevant here. The exit
4407a6a6cbcSPaolo Abeni 		 * conditions mirror closely tcp_recvmsg()
4417a6a6cbcSPaolo Abeni 		 */
4427a6a6cbcSPaolo Abeni 		if (copied >= target)
4437a6a6cbcSPaolo Abeni 			break;
4447a6a6cbcSPaolo Abeni 
4457a6a6cbcSPaolo Abeni 		if (copied) {
4467a6a6cbcSPaolo Abeni 			if (sk->sk_err ||
4477a6a6cbcSPaolo Abeni 			    sk->sk_state == TCP_CLOSE ||
4487a6a6cbcSPaolo Abeni 			    (sk->sk_shutdown & RCV_SHUTDOWN) ||
4497a6a6cbcSPaolo Abeni 			    !timeo ||
4507a6a6cbcSPaolo Abeni 			    signal_pending(current))
4517a6a6cbcSPaolo Abeni 				break;
4527a6a6cbcSPaolo Abeni 		} else {
4537a6a6cbcSPaolo Abeni 			if (sk->sk_err) {
4547a6a6cbcSPaolo Abeni 				copied = sock_error(sk);
4557a6a6cbcSPaolo Abeni 				break;
4567a6a6cbcSPaolo Abeni 			}
4577a6a6cbcSPaolo Abeni 
4587a6a6cbcSPaolo Abeni 			if (sk->sk_shutdown & RCV_SHUTDOWN)
4597a6a6cbcSPaolo Abeni 				break;
4607a6a6cbcSPaolo Abeni 
4617a6a6cbcSPaolo Abeni 			if (sk->sk_state == TCP_CLOSE) {
4627a6a6cbcSPaolo Abeni 				copied = -ENOTCONN;
4637a6a6cbcSPaolo Abeni 				break;
4647a6a6cbcSPaolo Abeni 			}
4657a6a6cbcSPaolo Abeni 
4667a6a6cbcSPaolo Abeni 			if (!timeo) {
4677a6a6cbcSPaolo Abeni 				copied = -EAGAIN;
4687a6a6cbcSPaolo Abeni 				break;
4697a6a6cbcSPaolo Abeni 			}
4707a6a6cbcSPaolo Abeni 
4717a6a6cbcSPaolo Abeni 			if (signal_pending(current)) {
4727a6a6cbcSPaolo Abeni 				copied = sock_intr_errno(timeo);
4737a6a6cbcSPaolo Abeni 				break;
4747a6a6cbcSPaolo Abeni 			}
4757a6a6cbcSPaolo Abeni 		}
4767a6a6cbcSPaolo Abeni 
4777a6a6cbcSPaolo Abeni 		pr_debug("block timeout %ld", timeo);
4787a6a6cbcSPaolo Abeni 		wait_data = true;
4797a6a6cbcSPaolo Abeni 		mptcp_wait_data(sk, &timeo);
4807a6a6cbcSPaolo Abeni 	}
4817a6a6cbcSPaolo Abeni 
4827a6a6cbcSPaolo Abeni 	if (more_data_avail) {
4837a6a6cbcSPaolo Abeni 		if (!test_bit(MPTCP_DATA_READY, &msk->flags))
4847a6a6cbcSPaolo Abeni 			set_bit(MPTCP_DATA_READY, &msk->flags);
4857a6a6cbcSPaolo Abeni 	} else if (!wait_data) {
4867a6a6cbcSPaolo Abeni 		clear_bit(MPTCP_DATA_READY, &msk->flags);
4877a6a6cbcSPaolo Abeni 
4887a6a6cbcSPaolo Abeni 		/* .. race-breaker: ssk might get new data after last
4897a6a6cbcSPaolo Abeni 		 * data_available() returns false.
4907a6a6cbcSPaolo Abeni 		 */
4917a6a6cbcSPaolo Abeni 		ssk = mptcp_subflow_recv_lookup(msk);
4927a6a6cbcSPaolo Abeni 		if (unlikely(ssk))
4937a6a6cbcSPaolo Abeni 			set_bit(MPTCP_DATA_READY, &msk->flags);
4947a6a6cbcSPaolo Abeni 	}
495cec37a6eSPeter Krystad 
496cec37a6eSPeter Krystad 	release_sock(sk);
497cec37a6eSPeter Krystad 	return copied;
498cec37a6eSPeter Krystad }
499cec37a6eSPeter Krystad 
500cec37a6eSPeter Krystad /* subflow sockets can be either outgoing (connect) or incoming
501cec37a6eSPeter Krystad  * (accept).
502cec37a6eSPeter Krystad  *
503cec37a6eSPeter Krystad  * Outgoing subflows use in-kernel sockets.
504cec37a6eSPeter Krystad  * Incoming subflows do not have their own 'struct socket' allocated,
505cec37a6eSPeter Krystad  * so we need to use tcp_close() after detaching them from the mptcp
506cec37a6eSPeter Krystad  * parent socket.
507cec37a6eSPeter Krystad  */
508cec37a6eSPeter Krystad static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
509cec37a6eSPeter Krystad 			      struct mptcp_subflow_context *subflow,
510cec37a6eSPeter Krystad 			      long timeout)
511cec37a6eSPeter Krystad {
512cec37a6eSPeter Krystad 	struct socket *sock = READ_ONCE(ssk->sk_socket);
513cec37a6eSPeter Krystad 
514cec37a6eSPeter Krystad 	list_del(&subflow->node);
515cec37a6eSPeter Krystad 
516cec37a6eSPeter Krystad 	if (sock && sock != sk->sk_socket) {
517cec37a6eSPeter Krystad 		/* outgoing subflow */
518cec37a6eSPeter Krystad 		sock_release(sock);
519cec37a6eSPeter Krystad 	} else {
520cec37a6eSPeter Krystad 		/* incoming subflow */
521cec37a6eSPeter Krystad 		tcp_close(ssk, timeout);
522cec37a6eSPeter Krystad 	}
523f870fa0bSMat Martineau }
524f870fa0bSMat Martineau 
525784325e9SMatthieu Baerts static int __mptcp_init_sock(struct sock *sk)
526f870fa0bSMat Martineau {
527cec37a6eSPeter Krystad 	struct mptcp_sock *msk = mptcp_sk(sk);
528cec37a6eSPeter Krystad 
529cec37a6eSPeter Krystad 	INIT_LIST_HEAD(&msk->conn_list);
5301891c4a0SFlorian Westphal 	__set_bit(MPTCP_SEND_SPACE, &msk->flags);
531cec37a6eSPeter Krystad 
532f870fa0bSMat Martineau 	return 0;
533f870fa0bSMat Martineau }
534f870fa0bSMat Martineau 
535784325e9SMatthieu Baerts static int mptcp_init_sock(struct sock *sk)
536784325e9SMatthieu Baerts {
537784325e9SMatthieu Baerts 	if (!mptcp_is_enabled(sock_net(sk)))
538784325e9SMatthieu Baerts 		return -ENOPROTOOPT;
539784325e9SMatthieu Baerts 
540784325e9SMatthieu Baerts 	return __mptcp_init_sock(sk);
541784325e9SMatthieu Baerts }
542784325e9SMatthieu Baerts 
54321498490SPeter Krystad static void mptcp_subflow_shutdown(struct sock *ssk, int how)
54421498490SPeter Krystad {
54521498490SPeter Krystad 	lock_sock(ssk);
54621498490SPeter Krystad 
54721498490SPeter Krystad 	switch (ssk->sk_state) {
54821498490SPeter Krystad 	case TCP_LISTEN:
54921498490SPeter Krystad 		if (!(how & RCV_SHUTDOWN))
55021498490SPeter Krystad 			break;
55121498490SPeter Krystad 		/* fall through */
55221498490SPeter Krystad 	case TCP_SYN_SENT:
55321498490SPeter Krystad 		tcp_disconnect(ssk, O_NONBLOCK);
55421498490SPeter Krystad 		break;
55521498490SPeter Krystad 	default:
55621498490SPeter Krystad 		ssk->sk_shutdown |= how;
55721498490SPeter Krystad 		tcp_shutdown(ssk, how);
55821498490SPeter Krystad 		break;
55921498490SPeter Krystad 	}
56021498490SPeter Krystad 
56121498490SPeter Krystad 	/* Wake up anyone sleeping in poll. */
56221498490SPeter Krystad 	ssk->sk_state_change(ssk);
56321498490SPeter Krystad 	release_sock(ssk);
56421498490SPeter Krystad }
56521498490SPeter Krystad 
566f870fa0bSMat Martineau static void mptcp_close(struct sock *sk, long timeout)
567f870fa0bSMat Martineau {
568cec37a6eSPeter Krystad 	struct mptcp_subflow_context *subflow, *tmp;
569f870fa0bSMat Martineau 	struct mptcp_sock *msk = mptcp_sk(sk);
570f870fa0bSMat Martineau 
57179c0949eSPeter Krystad 	mptcp_token_destroy(msk->token);
572f870fa0bSMat Martineau 	inet_sk_state_store(sk, TCP_CLOSE);
573f870fa0bSMat Martineau 
574cec37a6eSPeter Krystad 	lock_sock(sk);
575cec37a6eSPeter Krystad 
576cec37a6eSPeter Krystad 	list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
577cec37a6eSPeter Krystad 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
578cec37a6eSPeter Krystad 
579cec37a6eSPeter Krystad 		__mptcp_close_ssk(sk, ssk, subflow, timeout);
580f870fa0bSMat Martineau 	}
581f870fa0bSMat Martineau 
5826d0060f6SMat Martineau 	if (msk->cached_ext)
5836d0060f6SMat Martineau 		__skb_ext_put(msk->cached_ext);
584cec37a6eSPeter Krystad 	release_sock(sk);
585cec37a6eSPeter Krystad 	sk_common_release(sk);
586f870fa0bSMat Martineau }
587f870fa0bSMat Martineau 
588cf7da0d6SPeter Krystad static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
589cf7da0d6SPeter Krystad {
590cf7da0d6SPeter Krystad #if IS_ENABLED(CONFIG_MPTCP_IPV6)
591cf7da0d6SPeter Krystad 	const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
592cf7da0d6SPeter Krystad 	struct ipv6_pinfo *msk6 = inet6_sk(msk);
593cf7da0d6SPeter Krystad 
594cf7da0d6SPeter Krystad 	msk->sk_v6_daddr = ssk->sk_v6_daddr;
595cf7da0d6SPeter Krystad 	msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
596cf7da0d6SPeter Krystad 
597cf7da0d6SPeter Krystad 	if (msk6 && ssk6) {
598cf7da0d6SPeter Krystad 		msk6->saddr = ssk6->saddr;
599cf7da0d6SPeter Krystad 		msk6->flow_label = ssk6->flow_label;
600cf7da0d6SPeter Krystad 	}
601cf7da0d6SPeter Krystad #endif
602cf7da0d6SPeter Krystad 
603cf7da0d6SPeter Krystad 	inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
604cf7da0d6SPeter Krystad 	inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
605cf7da0d6SPeter Krystad 	inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
606cf7da0d6SPeter Krystad 	inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
607cf7da0d6SPeter Krystad 	inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
608cf7da0d6SPeter Krystad 	inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
609cf7da0d6SPeter Krystad }
610cf7da0d6SPeter Krystad 
611cf7da0d6SPeter Krystad static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
612cf7da0d6SPeter Krystad 				 bool kern)
613cf7da0d6SPeter Krystad {
614cf7da0d6SPeter Krystad 	struct mptcp_sock *msk = mptcp_sk(sk);
615cf7da0d6SPeter Krystad 	struct socket *listener;
616cf7da0d6SPeter Krystad 	struct sock *newsk;
617cf7da0d6SPeter Krystad 
618cf7da0d6SPeter Krystad 	listener = __mptcp_nmpc_socket(msk);
619cf7da0d6SPeter Krystad 	if (WARN_ON_ONCE(!listener)) {
620cf7da0d6SPeter Krystad 		*err = -EINVAL;
621cf7da0d6SPeter Krystad 		return NULL;
622cf7da0d6SPeter Krystad 	}
623cf7da0d6SPeter Krystad 
624cf7da0d6SPeter Krystad 	pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
625cf7da0d6SPeter Krystad 	newsk = inet_csk_accept(listener->sk, flags, err, kern);
626cf7da0d6SPeter Krystad 	if (!newsk)
627cf7da0d6SPeter Krystad 		return NULL;
628cf7da0d6SPeter Krystad 
629cf7da0d6SPeter Krystad 	pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
630cf7da0d6SPeter Krystad 
631cf7da0d6SPeter Krystad 	if (sk_is_mptcp(newsk)) {
632cf7da0d6SPeter Krystad 		struct mptcp_subflow_context *subflow;
633cf7da0d6SPeter Krystad 		struct sock *new_mptcp_sock;
634cf7da0d6SPeter Krystad 		struct sock *ssk = newsk;
6356d0060f6SMat Martineau 		u64 ack_seq;
636cf7da0d6SPeter Krystad 
637cf7da0d6SPeter Krystad 		subflow = mptcp_subflow_ctx(newsk);
638cf7da0d6SPeter Krystad 		lock_sock(sk);
639cf7da0d6SPeter Krystad 
640cf7da0d6SPeter Krystad 		local_bh_disable();
641cf7da0d6SPeter Krystad 		new_mptcp_sock = sk_clone_lock(sk, GFP_ATOMIC);
642cf7da0d6SPeter Krystad 		if (!new_mptcp_sock) {
643cf7da0d6SPeter Krystad 			*err = -ENOBUFS;
644cf7da0d6SPeter Krystad 			local_bh_enable();
645cf7da0d6SPeter Krystad 			release_sock(sk);
64621498490SPeter Krystad 			mptcp_subflow_shutdown(newsk, SHUT_RDWR + 1);
647cf7da0d6SPeter Krystad 			tcp_close(newsk, 0);
648cf7da0d6SPeter Krystad 			return NULL;
649cf7da0d6SPeter Krystad 		}
650cf7da0d6SPeter Krystad 
651784325e9SMatthieu Baerts 		__mptcp_init_sock(new_mptcp_sock);
652cf7da0d6SPeter Krystad 
653cf7da0d6SPeter Krystad 		msk = mptcp_sk(new_mptcp_sock);
654cf7da0d6SPeter Krystad 		msk->local_key = subflow->local_key;
65579c0949eSPeter Krystad 		msk->token = subflow->token;
656cf7da0d6SPeter Krystad 		msk->subflow = NULL;
657cf7da0d6SPeter Krystad 
65879c0949eSPeter Krystad 		mptcp_token_update_accept(newsk, new_mptcp_sock);
6596d0060f6SMat Martineau 
6606d0060f6SMat Martineau 		msk->write_seq = subflow->idsn + 1;
661*d22f4988SChristoph Paasch 		if (subflow->can_ack) {
662*d22f4988SChristoph Paasch 			msk->can_ack = true;
663*d22f4988SChristoph Paasch 			msk->remote_key = subflow->remote_key;
664*d22f4988SChristoph Paasch 			mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
6656d0060f6SMat Martineau 			ack_seq++;
6666d0060f6SMat Martineau 			msk->ack_seq = ack_seq;
667*d22f4988SChristoph Paasch 		}
668cf7da0d6SPeter Krystad 		newsk = new_mptcp_sock;
669cf7da0d6SPeter Krystad 		mptcp_copy_inaddrs(newsk, ssk);
670cf7da0d6SPeter Krystad 		list_add(&subflow->node, &msk->conn_list);
671cf7da0d6SPeter Krystad 
672cf7da0d6SPeter Krystad 		/* will be fully established at mptcp_stream_accept()
673cf7da0d6SPeter Krystad 		 * completion.
674cf7da0d6SPeter Krystad 		 */
675cf7da0d6SPeter Krystad 		inet_sk_state_store(new_mptcp_sock, TCP_SYN_RECV);
676cf7da0d6SPeter Krystad 		bh_unlock_sock(new_mptcp_sock);
677cf7da0d6SPeter Krystad 		local_bh_enable();
678cf7da0d6SPeter Krystad 		release_sock(sk);
6797a6a6cbcSPaolo Abeni 
6807a6a6cbcSPaolo Abeni 		/* the subflow can already receive packet, avoid racing with
6817a6a6cbcSPaolo Abeni 		 * the receive path and process the pending ones
6827a6a6cbcSPaolo Abeni 		 */
6837a6a6cbcSPaolo Abeni 		lock_sock(ssk);
6847a6a6cbcSPaolo Abeni 		subflow->rel_write_seq = 1;
6857a6a6cbcSPaolo Abeni 		subflow->tcp_sock = ssk;
6867a6a6cbcSPaolo Abeni 		subflow->conn = new_mptcp_sock;
6877a6a6cbcSPaolo Abeni 		if (unlikely(!skb_queue_empty(&ssk->sk_receive_queue)))
6887a6a6cbcSPaolo Abeni 			mptcp_subflow_data_available(ssk);
6897a6a6cbcSPaolo Abeni 		release_sock(ssk);
690cf7da0d6SPeter Krystad 	}
691cf7da0d6SPeter Krystad 
692cf7da0d6SPeter Krystad 	return newsk;
693cf7da0d6SPeter Krystad }
694cf7da0d6SPeter Krystad 
69579c0949eSPeter Krystad static void mptcp_destroy(struct sock *sk)
69679c0949eSPeter Krystad {
69779c0949eSPeter Krystad }
69879c0949eSPeter Krystad 
699717e79c8SPeter Krystad static int mptcp_setsockopt(struct sock *sk, int level, int optname,
700717e79c8SPeter Krystad 			    char __user *uoptval, unsigned int optlen)
701717e79c8SPeter Krystad {
702717e79c8SPeter Krystad 	struct mptcp_sock *msk = mptcp_sk(sk);
703717e79c8SPeter Krystad 	char __kernel *optval;
704717e79c8SPeter Krystad 	int ret = -EOPNOTSUPP;
705717e79c8SPeter Krystad 	struct socket *ssock;
706717e79c8SPeter Krystad 
707717e79c8SPeter Krystad 	/* will be treated as __user in tcp_setsockopt */
708717e79c8SPeter Krystad 	optval = (char __kernel __force *)uoptval;
709717e79c8SPeter Krystad 
710717e79c8SPeter Krystad 	pr_debug("msk=%p", msk);
711717e79c8SPeter Krystad 
712717e79c8SPeter Krystad 	/* @@ the meaning of setsockopt() when the socket is connected and
713717e79c8SPeter Krystad 	 * there are multiple subflows is not defined.
714717e79c8SPeter Krystad 	 */
715717e79c8SPeter Krystad 	lock_sock(sk);
716717e79c8SPeter Krystad 	ssock = __mptcp_socket_create(msk, MPTCP_SAME_STATE);
717717e79c8SPeter Krystad 	if (!IS_ERR(ssock)) {
718717e79c8SPeter Krystad 		pr_debug("subflow=%p", ssock->sk);
719717e79c8SPeter Krystad 		ret = kernel_setsockopt(ssock, level, optname, optval, optlen);
720717e79c8SPeter Krystad 	}
721717e79c8SPeter Krystad 	release_sock(sk);
722717e79c8SPeter Krystad 
723717e79c8SPeter Krystad 	return ret;
724717e79c8SPeter Krystad }
725717e79c8SPeter Krystad 
726717e79c8SPeter Krystad static int mptcp_getsockopt(struct sock *sk, int level, int optname,
727717e79c8SPeter Krystad 			    char __user *uoptval, int __user *uoption)
728717e79c8SPeter Krystad {
729717e79c8SPeter Krystad 	struct mptcp_sock *msk = mptcp_sk(sk);
730717e79c8SPeter Krystad 	char __kernel *optval;
731717e79c8SPeter Krystad 	int ret = -EOPNOTSUPP;
732717e79c8SPeter Krystad 	int __kernel *option;
733717e79c8SPeter Krystad 	struct socket *ssock;
734717e79c8SPeter Krystad 
735717e79c8SPeter Krystad 	/* will be treated as __user in tcp_getsockopt */
736717e79c8SPeter Krystad 	optval = (char __kernel __force *)uoptval;
737717e79c8SPeter Krystad 	option = (int __kernel __force *)uoption;
738717e79c8SPeter Krystad 
739717e79c8SPeter Krystad 	pr_debug("msk=%p", msk);
740717e79c8SPeter Krystad 
741717e79c8SPeter Krystad 	/* @@ the meaning of getsockopt() when the socket is connected and
742717e79c8SPeter Krystad 	 * there are multiple subflows is not defined.
743717e79c8SPeter Krystad 	 */
744717e79c8SPeter Krystad 	lock_sock(sk);
745717e79c8SPeter Krystad 	ssock = __mptcp_socket_create(msk, MPTCP_SAME_STATE);
746717e79c8SPeter Krystad 	if (!IS_ERR(ssock)) {
747717e79c8SPeter Krystad 		pr_debug("subflow=%p", ssock->sk);
748717e79c8SPeter Krystad 		ret = kernel_getsockopt(ssock, level, optname, optval, option);
749717e79c8SPeter Krystad 	}
750717e79c8SPeter Krystad 	release_sock(sk);
751717e79c8SPeter Krystad 
752717e79c8SPeter Krystad 	return ret;
753717e79c8SPeter Krystad }
754717e79c8SPeter Krystad 
755cec37a6eSPeter Krystad static int mptcp_get_port(struct sock *sk, unsigned short snum)
756f870fa0bSMat Martineau {
757f870fa0bSMat Martineau 	struct mptcp_sock *msk = mptcp_sk(sk);
758cec37a6eSPeter Krystad 	struct socket *ssock;
759f870fa0bSMat Martineau 
760cec37a6eSPeter Krystad 	ssock = __mptcp_nmpc_socket(msk);
761cec37a6eSPeter Krystad 	pr_debug("msk=%p, subflow=%p", msk, ssock);
762cec37a6eSPeter Krystad 	if (WARN_ON_ONCE(!ssock))
763cec37a6eSPeter Krystad 		return -EINVAL;
764f870fa0bSMat Martineau 
765cec37a6eSPeter Krystad 	return inet_csk_get_port(ssock->sk, snum);
766cec37a6eSPeter Krystad }
767f870fa0bSMat Martineau 
768cec37a6eSPeter Krystad void mptcp_finish_connect(struct sock *ssk)
769cec37a6eSPeter Krystad {
770cec37a6eSPeter Krystad 	struct mptcp_subflow_context *subflow;
771cec37a6eSPeter Krystad 	struct mptcp_sock *msk;
772cec37a6eSPeter Krystad 	struct sock *sk;
7736d0060f6SMat Martineau 	u64 ack_seq;
774f870fa0bSMat Martineau 
775cec37a6eSPeter Krystad 	subflow = mptcp_subflow_ctx(ssk);
776f870fa0bSMat Martineau 
777cec37a6eSPeter Krystad 	if (!subflow->mp_capable)
778cec37a6eSPeter Krystad 		return;
779cec37a6eSPeter Krystad 
780cec37a6eSPeter Krystad 	sk = subflow->conn;
781cec37a6eSPeter Krystad 	msk = mptcp_sk(sk);
782cec37a6eSPeter Krystad 
783648ef4b8SMat Martineau 	pr_debug("msk=%p, token=%u", sk, subflow->token);
784648ef4b8SMat Martineau 
7856d0060f6SMat Martineau 	mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
7866d0060f6SMat Martineau 	ack_seq++;
787648ef4b8SMat Martineau 	subflow->map_seq = ack_seq;
788648ef4b8SMat Martineau 	subflow->map_subflow_seq = 1;
7896d0060f6SMat Martineau 	subflow->rel_write_seq = 1;
7906d0060f6SMat Martineau 
791cec37a6eSPeter Krystad 	/* the socket is not connected yet, no msk/subflow ops can access/race
792cec37a6eSPeter Krystad 	 * accessing the field below
793cec37a6eSPeter Krystad 	 */
794cec37a6eSPeter Krystad 	WRITE_ONCE(msk->remote_key, subflow->remote_key);
795cec37a6eSPeter Krystad 	WRITE_ONCE(msk->local_key, subflow->local_key);
79679c0949eSPeter Krystad 	WRITE_ONCE(msk->token, subflow->token);
7976d0060f6SMat Martineau 	WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
7986d0060f6SMat Martineau 	WRITE_ONCE(msk->ack_seq, ack_seq);
799*d22f4988SChristoph Paasch 	WRITE_ONCE(msk->can_ack, 1);
800f870fa0bSMat Martineau }
801f870fa0bSMat Martineau 
802cf7da0d6SPeter Krystad static void mptcp_sock_graft(struct sock *sk, struct socket *parent)
803cf7da0d6SPeter Krystad {
804cf7da0d6SPeter Krystad 	write_lock_bh(&sk->sk_callback_lock);
805cf7da0d6SPeter Krystad 	rcu_assign_pointer(sk->sk_wq, &parent->wq);
806cf7da0d6SPeter Krystad 	sk_set_socket(sk, parent);
807cf7da0d6SPeter Krystad 	sk->sk_uid = SOCK_INODE(parent)->i_uid;
808cf7da0d6SPeter Krystad 	write_unlock_bh(&sk->sk_callback_lock);
809cf7da0d6SPeter Krystad }
810cf7da0d6SPeter Krystad 
8111891c4a0SFlorian Westphal static bool mptcp_memory_free(const struct sock *sk, int wake)
8121891c4a0SFlorian Westphal {
8131891c4a0SFlorian Westphal 	struct mptcp_sock *msk = mptcp_sk(sk);
8141891c4a0SFlorian Westphal 
8151891c4a0SFlorian Westphal 	return wake ? test_bit(MPTCP_SEND_SPACE, &msk->flags) : true;
8161891c4a0SFlorian Westphal }
8171891c4a0SFlorian Westphal 
818f870fa0bSMat Martineau static struct proto mptcp_prot = {
819f870fa0bSMat Martineau 	.name		= "MPTCP",
820f870fa0bSMat Martineau 	.owner		= THIS_MODULE,
821f870fa0bSMat Martineau 	.init		= mptcp_init_sock,
822f870fa0bSMat Martineau 	.close		= mptcp_close,
823cf7da0d6SPeter Krystad 	.accept		= mptcp_accept,
824717e79c8SPeter Krystad 	.setsockopt	= mptcp_setsockopt,
825717e79c8SPeter Krystad 	.getsockopt	= mptcp_getsockopt,
826f870fa0bSMat Martineau 	.shutdown	= tcp_shutdown,
82779c0949eSPeter Krystad 	.destroy	= mptcp_destroy,
828f870fa0bSMat Martineau 	.sendmsg	= mptcp_sendmsg,
829f870fa0bSMat Martineau 	.recvmsg	= mptcp_recvmsg,
830f870fa0bSMat Martineau 	.hash		= inet_hash,
831f870fa0bSMat Martineau 	.unhash		= inet_unhash,
832cec37a6eSPeter Krystad 	.get_port	= mptcp_get_port,
8331891c4a0SFlorian Westphal 	.stream_memory_free	= mptcp_memory_free,
834f870fa0bSMat Martineau 	.obj_size	= sizeof(struct mptcp_sock),
835f870fa0bSMat Martineau 	.no_autobind	= true,
836f870fa0bSMat Martineau };
837f870fa0bSMat Martineau 
8382303f994SPeter Krystad static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
8392303f994SPeter Krystad {
8402303f994SPeter Krystad 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
8412303f994SPeter Krystad 	struct socket *ssock;
842cf7da0d6SPeter Krystad 	int err;
8432303f994SPeter Krystad 
8442303f994SPeter Krystad 	lock_sock(sock->sk);
8452303f994SPeter Krystad 	ssock = __mptcp_socket_create(msk, MPTCP_SAME_STATE);
8462303f994SPeter Krystad 	if (IS_ERR(ssock)) {
8472303f994SPeter Krystad 		err = PTR_ERR(ssock);
8482303f994SPeter Krystad 		goto unlock;
8492303f994SPeter Krystad 	}
8502303f994SPeter Krystad 
8512303f994SPeter Krystad 	err = ssock->ops->bind(ssock, uaddr, addr_len);
852cf7da0d6SPeter Krystad 	if (!err)
853cf7da0d6SPeter Krystad 		mptcp_copy_inaddrs(sock->sk, ssock->sk);
8542303f994SPeter Krystad 
8552303f994SPeter Krystad unlock:
8562303f994SPeter Krystad 	release_sock(sock->sk);
8572303f994SPeter Krystad 	return err;
8582303f994SPeter Krystad }
8592303f994SPeter Krystad 
8602303f994SPeter Krystad static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
8612303f994SPeter Krystad 				int addr_len, int flags)
8622303f994SPeter Krystad {
8632303f994SPeter Krystad 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
8642303f994SPeter Krystad 	struct socket *ssock;
8652303f994SPeter Krystad 	int err;
8662303f994SPeter Krystad 
8672303f994SPeter Krystad 	lock_sock(sock->sk);
8682303f994SPeter Krystad 	ssock = __mptcp_socket_create(msk, TCP_SYN_SENT);
8692303f994SPeter Krystad 	if (IS_ERR(ssock)) {
8702303f994SPeter Krystad 		err = PTR_ERR(ssock);
8712303f994SPeter Krystad 		goto unlock;
8722303f994SPeter Krystad 	}
8732303f994SPeter Krystad 
874cf7da0d6SPeter Krystad #ifdef CONFIG_TCP_MD5SIG
875cf7da0d6SPeter Krystad 	/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
876cf7da0d6SPeter Krystad 	 * TCP option space.
877cf7da0d6SPeter Krystad 	 */
878cf7da0d6SPeter Krystad 	if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
879cf7da0d6SPeter Krystad 		mptcp_subflow_ctx(ssock->sk)->request_mptcp = 0;
880cf7da0d6SPeter Krystad #endif
881cf7da0d6SPeter Krystad 
8822303f994SPeter Krystad 	err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
8832303f994SPeter Krystad 	inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
884cf7da0d6SPeter Krystad 	mptcp_copy_inaddrs(sock->sk, ssock->sk);
8852303f994SPeter Krystad 
8862303f994SPeter Krystad unlock:
8872303f994SPeter Krystad 	release_sock(sock->sk);
8882303f994SPeter Krystad 	return err;
8892303f994SPeter Krystad }
8902303f994SPeter Krystad 
891cf7da0d6SPeter Krystad static int mptcp_v4_getname(struct socket *sock, struct sockaddr *uaddr,
892cf7da0d6SPeter Krystad 			    int peer)
893cf7da0d6SPeter Krystad {
894cf7da0d6SPeter Krystad 	if (sock->sk->sk_prot == &tcp_prot) {
895cf7da0d6SPeter Krystad 		/* we are being invoked from __sys_accept4, after
896cf7da0d6SPeter Krystad 		 * mptcp_accept() has just accepted a non-mp-capable
897cf7da0d6SPeter Krystad 		 * flow: sk is a tcp_sk, not an mptcp one.
898cf7da0d6SPeter Krystad 		 *
899cf7da0d6SPeter Krystad 		 * Hand the socket over to tcp so all further socket ops
900cf7da0d6SPeter Krystad 		 * bypass mptcp.
901cf7da0d6SPeter Krystad 		 */
902cf7da0d6SPeter Krystad 		sock->ops = &inet_stream_ops;
903cf7da0d6SPeter Krystad 	}
904cf7da0d6SPeter Krystad 
905cf7da0d6SPeter Krystad 	return inet_getname(sock, uaddr, peer);
906cf7da0d6SPeter Krystad }
907cf7da0d6SPeter Krystad 
908cf7da0d6SPeter Krystad #if IS_ENABLED(CONFIG_MPTCP_IPV6)
909cf7da0d6SPeter Krystad static int mptcp_v6_getname(struct socket *sock, struct sockaddr *uaddr,
910cf7da0d6SPeter Krystad 			    int peer)
911cf7da0d6SPeter Krystad {
912cf7da0d6SPeter Krystad 	if (sock->sk->sk_prot == &tcpv6_prot) {
913cf7da0d6SPeter Krystad 		/* we are being invoked from __sys_accept4 after
914cf7da0d6SPeter Krystad 		 * mptcp_accept() has accepted a non-mp-capable
915cf7da0d6SPeter Krystad 		 * subflow: sk is a tcp_sk, not mptcp.
916cf7da0d6SPeter Krystad 		 *
917cf7da0d6SPeter Krystad 		 * Hand the socket over to tcp so all further
918cf7da0d6SPeter Krystad 		 * socket ops bypass mptcp.
919cf7da0d6SPeter Krystad 		 */
920cf7da0d6SPeter Krystad 		sock->ops = &inet6_stream_ops;
921cf7da0d6SPeter Krystad 	}
922cf7da0d6SPeter Krystad 
923cf7da0d6SPeter Krystad 	return inet6_getname(sock, uaddr, peer);
924cf7da0d6SPeter Krystad }
925cf7da0d6SPeter Krystad #endif
926cf7da0d6SPeter Krystad 
927cf7da0d6SPeter Krystad static int mptcp_listen(struct socket *sock, int backlog)
928cf7da0d6SPeter Krystad {
929cf7da0d6SPeter Krystad 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
930cf7da0d6SPeter Krystad 	struct socket *ssock;
931cf7da0d6SPeter Krystad 	int err;
932cf7da0d6SPeter Krystad 
933cf7da0d6SPeter Krystad 	pr_debug("msk=%p", msk);
934cf7da0d6SPeter Krystad 
935cf7da0d6SPeter Krystad 	lock_sock(sock->sk);
936cf7da0d6SPeter Krystad 	ssock = __mptcp_socket_create(msk, TCP_LISTEN);
937cf7da0d6SPeter Krystad 	if (IS_ERR(ssock)) {
938cf7da0d6SPeter Krystad 		err = PTR_ERR(ssock);
939cf7da0d6SPeter Krystad 		goto unlock;
940cf7da0d6SPeter Krystad 	}
941cf7da0d6SPeter Krystad 
942cf7da0d6SPeter Krystad 	err = ssock->ops->listen(ssock, backlog);
943cf7da0d6SPeter Krystad 	inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
944cf7da0d6SPeter Krystad 	if (!err)
945cf7da0d6SPeter Krystad 		mptcp_copy_inaddrs(sock->sk, ssock->sk);
946cf7da0d6SPeter Krystad 
947cf7da0d6SPeter Krystad unlock:
948cf7da0d6SPeter Krystad 	release_sock(sock->sk);
949cf7da0d6SPeter Krystad 	return err;
950cf7da0d6SPeter Krystad }
951cf7da0d6SPeter Krystad 
952cf7da0d6SPeter Krystad static bool is_tcp_proto(const struct proto *p)
953cf7da0d6SPeter Krystad {
954cf7da0d6SPeter Krystad #if IS_ENABLED(CONFIG_MPTCP_IPV6)
955cf7da0d6SPeter Krystad 	return p == &tcp_prot || p == &tcpv6_prot;
956cf7da0d6SPeter Krystad #else
957cf7da0d6SPeter Krystad 	return p == &tcp_prot;
958cf7da0d6SPeter Krystad #endif
959cf7da0d6SPeter Krystad }
960cf7da0d6SPeter Krystad 
961cf7da0d6SPeter Krystad static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
962cf7da0d6SPeter Krystad 			       int flags, bool kern)
963cf7da0d6SPeter Krystad {
964cf7da0d6SPeter Krystad 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
965cf7da0d6SPeter Krystad 	struct socket *ssock;
966cf7da0d6SPeter Krystad 	int err;
967cf7da0d6SPeter Krystad 
968cf7da0d6SPeter Krystad 	pr_debug("msk=%p", msk);
969cf7da0d6SPeter Krystad 
970cf7da0d6SPeter Krystad 	lock_sock(sock->sk);
971cf7da0d6SPeter Krystad 	if (sock->sk->sk_state != TCP_LISTEN)
972cf7da0d6SPeter Krystad 		goto unlock_fail;
973cf7da0d6SPeter Krystad 
974cf7da0d6SPeter Krystad 	ssock = __mptcp_nmpc_socket(msk);
975cf7da0d6SPeter Krystad 	if (!ssock)
976cf7da0d6SPeter Krystad 		goto unlock_fail;
977cf7da0d6SPeter Krystad 
978cf7da0d6SPeter Krystad 	sock_hold(ssock->sk);
979cf7da0d6SPeter Krystad 	release_sock(sock->sk);
980cf7da0d6SPeter Krystad 
981cf7da0d6SPeter Krystad 	err = ssock->ops->accept(sock, newsock, flags, kern);
982cf7da0d6SPeter Krystad 	if (err == 0 && !is_tcp_proto(newsock->sk->sk_prot)) {
983cf7da0d6SPeter Krystad 		struct mptcp_sock *msk = mptcp_sk(newsock->sk);
984cf7da0d6SPeter Krystad 		struct mptcp_subflow_context *subflow;
985cf7da0d6SPeter Krystad 
986cf7da0d6SPeter Krystad 		/* set ssk->sk_socket of accept()ed flows to mptcp socket.
987cf7da0d6SPeter Krystad 		 * This is needed so NOSPACE flag can be set from tcp stack.
988cf7da0d6SPeter Krystad 		 */
989cf7da0d6SPeter Krystad 		list_for_each_entry(subflow, &msk->conn_list, node) {
990cf7da0d6SPeter Krystad 			struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
991cf7da0d6SPeter Krystad 
992cf7da0d6SPeter Krystad 			if (!ssk->sk_socket)
993cf7da0d6SPeter Krystad 				mptcp_sock_graft(ssk, newsock);
994cf7da0d6SPeter Krystad 		}
995cf7da0d6SPeter Krystad 
996cf7da0d6SPeter Krystad 		inet_sk_state_store(newsock->sk, TCP_ESTABLISHED);
997cf7da0d6SPeter Krystad 	}
998cf7da0d6SPeter Krystad 
999cf7da0d6SPeter Krystad 	sock_put(ssock->sk);
1000cf7da0d6SPeter Krystad 	return err;
1001cf7da0d6SPeter Krystad 
1002cf7da0d6SPeter Krystad unlock_fail:
1003cf7da0d6SPeter Krystad 	release_sock(sock->sk);
1004cf7da0d6SPeter Krystad 	return -EINVAL;
1005cf7da0d6SPeter Krystad }
1006cf7da0d6SPeter Krystad 
10072303f994SPeter Krystad static __poll_t mptcp_poll(struct file *file, struct socket *sock,
10082303f994SPeter Krystad 			   struct poll_table_struct *wait)
10092303f994SPeter Krystad {
10101891c4a0SFlorian Westphal 	const struct mptcp_sock *msk;
10111891c4a0SFlorian Westphal 	struct sock *sk = sock->sk;
10121891c4a0SFlorian Westphal 	struct socket *ssock;
10132303f994SPeter Krystad 	__poll_t mask = 0;
10142303f994SPeter Krystad 
10151891c4a0SFlorian Westphal 	msk = mptcp_sk(sk);
10161891c4a0SFlorian Westphal 	lock_sock(sk);
10171891c4a0SFlorian Westphal 	ssock = __mptcp_nmpc_socket(msk);
10181891c4a0SFlorian Westphal 	if (ssock) {
10191891c4a0SFlorian Westphal 		mask = ssock->ops->poll(file, ssock, wait);
10201891c4a0SFlorian Westphal 		release_sock(sk);
10211891c4a0SFlorian Westphal 		return mask;
10221891c4a0SFlorian Westphal 	}
10231891c4a0SFlorian Westphal 
10241891c4a0SFlorian Westphal 	release_sock(sk);
10251891c4a0SFlorian Westphal 	sock_poll_wait(file, sock, wait);
10261891c4a0SFlorian Westphal 	lock_sock(sk);
10271891c4a0SFlorian Westphal 
10281891c4a0SFlorian Westphal 	if (test_bit(MPTCP_DATA_READY, &msk->flags))
10291891c4a0SFlorian Westphal 		mask = EPOLLIN | EPOLLRDNORM;
10301891c4a0SFlorian Westphal 	if (sk_stream_is_writeable(sk) &&
10311891c4a0SFlorian Westphal 	    test_bit(MPTCP_SEND_SPACE, &msk->flags))
10321891c4a0SFlorian Westphal 		mask |= EPOLLOUT | EPOLLWRNORM;
10331891c4a0SFlorian Westphal 	if (sk->sk_shutdown & RCV_SHUTDOWN)
10341891c4a0SFlorian Westphal 		mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
10351891c4a0SFlorian Westphal 
10361891c4a0SFlorian Westphal 	release_sock(sk);
10371891c4a0SFlorian Westphal 
10382303f994SPeter Krystad 	return mask;
10392303f994SPeter Krystad }
10402303f994SPeter Krystad 
104121498490SPeter Krystad static int mptcp_shutdown(struct socket *sock, int how)
104221498490SPeter Krystad {
104321498490SPeter Krystad 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
104421498490SPeter Krystad 	struct mptcp_subflow_context *subflow;
104521498490SPeter Krystad 	int ret = 0;
104621498490SPeter Krystad 
104721498490SPeter Krystad 	pr_debug("sk=%p, how=%d", msk, how);
104821498490SPeter Krystad 
104921498490SPeter Krystad 	lock_sock(sock->sk);
105021498490SPeter Krystad 
105121498490SPeter Krystad 	if (how == SHUT_WR || how == SHUT_RDWR)
105221498490SPeter Krystad 		inet_sk_state_store(sock->sk, TCP_FIN_WAIT1);
105321498490SPeter Krystad 
105421498490SPeter Krystad 	how++;
105521498490SPeter Krystad 
105621498490SPeter Krystad 	if ((how & ~SHUTDOWN_MASK) || !how) {
105721498490SPeter Krystad 		ret = -EINVAL;
105821498490SPeter Krystad 		goto out_unlock;
105921498490SPeter Krystad 	}
106021498490SPeter Krystad 
106121498490SPeter Krystad 	if (sock->state == SS_CONNECTING) {
106221498490SPeter Krystad 		if ((1 << sock->sk->sk_state) &
106321498490SPeter Krystad 		    (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))
106421498490SPeter Krystad 			sock->state = SS_DISCONNECTING;
106521498490SPeter Krystad 		else
106621498490SPeter Krystad 			sock->state = SS_CONNECTED;
106721498490SPeter Krystad 	}
106821498490SPeter Krystad 
106921498490SPeter Krystad 	mptcp_for_each_subflow(msk, subflow) {
107021498490SPeter Krystad 		struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
107121498490SPeter Krystad 
107221498490SPeter Krystad 		mptcp_subflow_shutdown(tcp_sk, how);
107321498490SPeter Krystad 	}
107421498490SPeter Krystad 
107521498490SPeter Krystad out_unlock:
107621498490SPeter Krystad 	release_sock(sock->sk);
107721498490SPeter Krystad 
107821498490SPeter Krystad 	return ret;
107921498490SPeter Krystad }
108021498490SPeter Krystad 
10812303f994SPeter Krystad static struct proto_ops mptcp_stream_ops;
10822303f994SPeter Krystad 
1083f870fa0bSMat Martineau static struct inet_protosw mptcp_protosw = {
1084f870fa0bSMat Martineau 	.type		= SOCK_STREAM,
1085f870fa0bSMat Martineau 	.protocol	= IPPROTO_MPTCP,
1086f870fa0bSMat Martineau 	.prot		= &mptcp_prot,
10872303f994SPeter Krystad 	.ops		= &mptcp_stream_ops,
10882303f994SPeter Krystad 	.flags		= INET_PROTOSW_ICSK,
1089f870fa0bSMat Martineau };
1090f870fa0bSMat Martineau 
1091784325e9SMatthieu Baerts void mptcp_proto_init(void)
1092f870fa0bSMat Martineau {
10932303f994SPeter Krystad 	mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
10942303f994SPeter Krystad 	mptcp_stream_ops = inet_stream_ops;
10952303f994SPeter Krystad 	mptcp_stream_ops.bind = mptcp_bind;
10962303f994SPeter Krystad 	mptcp_stream_ops.connect = mptcp_stream_connect;
10972303f994SPeter Krystad 	mptcp_stream_ops.poll = mptcp_poll;
1098cf7da0d6SPeter Krystad 	mptcp_stream_ops.accept = mptcp_stream_accept;
1099cf7da0d6SPeter Krystad 	mptcp_stream_ops.getname = mptcp_v4_getname;
1100cf7da0d6SPeter Krystad 	mptcp_stream_ops.listen = mptcp_listen;
110121498490SPeter Krystad 	mptcp_stream_ops.shutdown = mptcp_shutdown;
11022303f994SPeter Krystad 
11032303f994SPeter Krystad 	mptcp_subflow_init();
11042303f994SPeter Krystad 
1105f870fa0bSMat Martineau 	if (proto_register(&mptcp_prot, 1) != 0)
1106f870fa0bSMat Martineau 		panic("Failed to register MPTCP proto.\n");
1107f870fa0bSMat Martineau 
1108f870fa0bSMat Martineau 	inet_register_protosw(&mptcp_protosw);
1109f870fa0bSMat Martineau }
1110f870fa0bSMat Martineau 
1111f870fa0bSMat Martineau #if IS_ENABLED(CONFIG_MPTCP_IPV6)
11122303f994SPeter Krystad static struct proto_ops mptcp_v6_stream_ops;
1113f870fa0bSMat Martineau static struct proto mptcp_v6_prot;
1114f870fa0bSMat Martineau 
111579c0949eSPeter Krystad static void mptcp_v6_destroy(struct sock *sk)
111679c0949eSPeter Krystad {
111779c0949eSPeter Krystad 	mptcp_destroy(sk);
111879c0949eSPeter Krystad 	inet6_destroy_sock(sk);
111979c0949eSPeter Krystad }
112079c0949eSPeter Krystad 
1121f870fa0bSMat Martineau static struct inet_protosw mptcp_v6_protosw = {
1122f870fa0bSMat Martineau 	.type		= SOCK_STREAM,
1123f870fa0bSMat Martineau 	.protocol	= IPPROTO_MPTCP,
1124f870fa0bSMat Martineau 	.prot		= &mptcp_v6_prot,
11252303f994SPeter Krystad 	.ops		= &mptcp_v6_stream_ops,
1126f870fa0bSMat Martineau 	.flags		= INET_PROTOSW_ICSK,
1127f870fa0bSMat Martineau };
1128f870fa0bSMat Martineau 
1129784325e9SMatthieu Baerts int mptcp_proto_v6_init(void)
1130f870fa0bSMat Martineau {
1131f870fa0bSMat Martineau 	int err;
1132f870fa0bSMat Martineau 
1133f870fa0bSMat Martineau 	mptcp_v6_prot = mptcp_prot;
1134f870fa0bSMat Martineau 	strcpy(mptcp_v6_prot.name, "MPTCPv6");
1135f870fa0bSMat Martineau 	mptcp_v6_prot.slab = NULL;
113679c0949eSPeter Krystad 	mptcp_v6_prot.destroy = mptcp_v6_destroy;
1137f870fa0bSMat Martineau 	mptcp_v6_prot.obj_size = sizeof(struct mptcp_sock) +
1138f870fa0bSMat Martineau 				 sizeof(struct ipv6_pinfo);
1139f870fa0bSMat Martineau 
1140f870fa0bSMat Martineau 	err = proto_register(&mptcp_v6_prot, 1);
1141f870fa0bSMat Martineau 	if (err)
1142f870fa0bSMat Martineau 		return err;
1143f870fa0bSMat Martineau 
11442303f994SPeter Krystad 	mptcp_v6_stream_ops = inet6_stream_ops;
11452303f994SPeter Krystad 	mptcp_v6_stream_ops.bind = mptcp_bind;
11462303f994SPeter Krystad 	mptcp_v6_stream_ops.connect = mptcp_stream_connect;
11472303f994SPeter Krystad 	mptcp_v6_stream_ops.poll = mptcp_poll;
1148cf7da0d6SPeter Krystad 	mptcp_v6_stream_ops.accept = mptcp_stream_accept;
1149cf7da0d6SPeter Krystad 	mptcp_v6_stream_ops.getname = mptcp_v6_getname;
1150cf7da0d6SPeter Krystad 	mptcp_v6_stream_ops.listen = mptcp_listen;
115121498490SPeter Krystad 	mptcp_v6_stream_ops.shutdown = mptcp_shutdown;
11522303f994SPeter Krystad 
1153f870fa0bSMat Martineau 	err = inet6_register_protosw(&mptcp_v6_protosw);
1154f870fa0bSMat Martineau 	if (err)
1155f870fa0bSMat Martineau 		proto_unregister(&mptcp_v6_prot);
1156f870fa0bSMat Martineau 
1157f870fa0bSMat Martineau 	return err;
1158f870fa0bSMat Martineau }
1159f870fa0bSMat Martineau #endif
1160