Merging upstream version 6.10.3.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

10 files changed, 196 insertions, 56 deletions

diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c
index 2963ba84e2..98b1dd498f 100644
--- a/net/mptcp/ctrl.c
+++ b/net/mptcp/ctrl.c
@@ -92,7 +92,7 @@ static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
 	pernet->allow_join_initial_addr_port = 1;
 	pernet->stale_loss_cnt = 4;
 	pernet->pm_type = MPTCP_PM_TYPE_KERNEL;
-	strcpy(pernet->scheduler, "default");
+	strscpy(pernet->scheduler, "default", sizeof(pernet->scheduler));
 }
 
 #ifdef CONFIG_SYSCTL
@@ -133,6 +133,24 @@ static int proc_scheduler(struct ctl_table *ctl, int write,
 	return ret;
 }
 
+static int proc_available_schedulers(struct ctl_table *ctl,
+				     int write, void *buffer,
+				     size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table tbl = { .maxlen = MPTCP_SCHED_BUF_MAX, };
+	int ret;
+
+	tbl.data = kmalloc(tbl.maxlen, GFP_USER);
+	if (!tbl.data)
+		return -ENOMEM;
+
+	mptcp_get_available_schedulers(tbl.data, MPTCP_SCHED_BUF_MAX);
+	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
+	kfree(tbl.data);
+
+	return ret;
+}
+
 static struct ctl_table mptcp_sysctl_table[] = {
 	{
 		.procname = "enabled",
@@ -188,12 +206,17 @@ static struct ctl_table mptcp_sysctl_table[] = {
 		.proc_handler = proc_scheduler,
 	},
 	{
+		.procname = "available_schedulers",
+		.maxlen	= MPTCP_SCHED_BUF_MAX,
+		.mode = 0644,
+		.proc_handler = proc_available_schedulers,
+	},
+	{
 		.procname = "close_timeout",
 		.maxlen = sizeof(unsigned int),
 		.mode = 0644,
 		.proc_handler = proc_dointvec_jiffies,
 	},
-	{}
 };
 
 static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet)
@@ -215,7 +238,8 @@ static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet)
 	table[4].data = &pernet->stale_loss_cnt;
 	table[5].data = &pernet->pm_type;
 	table[6].data = &pernet->scheduler;
-	table[7].data = &pernet->close_timeout;
+	/* table[7] is for available_schedulers which is read-only info */
+	table[8].data = &pernet->close_timeout;
 
 	hdr = register_net_sysctl_sz(net, MPTCP_SYSCTL_PATH, table,
 				     ARRAY_SIZE(mptcp_sysctl_table));
@@ -235,7 +259,7 @@ err_alloc:
 
 static void mptcp_pernet_del_table(struct mptcp_pernet *pernet)
 {
-	struct ctl_table *table = pernet->ctl_table_hdr->ctl_table_arg;
+	const struct ctl_table *table = pernet->ctl_table_hdr->ctl_table_arg;
 
 	unregister_net_sysctl_table(pernet->ctl_table_hdr);
 
diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
index dd7fd1f246..2704afd0df 100644
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
+#include <net/inet_common.h>
+
 enum linux_mptcp_mib_field {
 	MPTCP_MIB_NUM = 0,
 	MPTCP_MIB_MPCAPABLEPASSIVE,	/* Received SYN with MP_CAPABLE */
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 27ca42c77b..8e8dcfbc29 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1068,6 +1068,7 @@ static void ack_update_msk(struct mptcp_sock *msk,
 		__mptcp_snd_una_update(msk, new_snd_una);
 		__mptcp_data_acked(sk);
 	}
+	msk->last_ack_recv = tcp_jiffies32;
 	mptcp_data_unlock(sk);
 
 	trace_ack_update_msk(mp_opt->data_ack,
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 8bf7ed6d63..ea9e5817b9 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -14,6 +14,7 @@
 
 #include "protocol.h"
 #include "mib.h"
+#include "mptcp_pm_gen.h"
 
 static int pm_nl_pernet_id;
 
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index 9f5d422d5e..f0a4590506 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -6,6 +6,7 @@
 
 #include "protocol.h"
 #include "mib.h"
+#include "mptcp_pm_gen.h"
 
 void mptcp_free_local_addr_list(struct mptcp_sock *msk)
 {
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 68e4c08648..bb7dca8aa2 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -20,6 +20,7 @@
 #include <net/transp_v6.h>
 #endif
 #include <net/mptcp.h>
+#include <net/hotdata.h>
 #include <net/xfrm.h>
 #include <asm/ioctls.h>
 #include "protocol.h"
@@ -706,6 +707,8 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
 		}
 	} while (more_data_avail);
 
+	if (moved > 0)
+		msk->last_data_recv = tcp_jiffies32;
 	*bytes += moved;
 	return done;
 }
@@ -1270,7 +1273,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 
 		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)) {
+		if (!can_coalesce && i >= READ_ONCE(net_hotdata.sysctl_max_skb_frags)) {
 			tcp_mark_push(tcp_sk(ssk), skb);
 			goto alloc_skb;
 		}
@@ -1556,6 +1559,8 @@ static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
 	err = copied;
 
 out:
+	if (err > 0)
+		msk->last_data_sent = tcp_jiffies32;
 	return err;
 }
 
@@ -2056,7 +2061,7 @@ static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
 				ssk = mptcp_subflow_tcp_sock(subflow);
 				slow = lock_sock_fast(ssk);
 				WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
-				tcp_sk(ssk)->window_clamp = window_clamp;
+				WRITE_ONCE(tcp_sk(ssk)->window_clamp, window_clamp);
 				tcp_cleanup_rbuf(ssk, 1);
 				unlock_sock_fast(ssk, slow);
 			}
@@ -2565,7 +2570,7 @@ static void mptcp_check_fastclose(struct mptcp_sock *msk)
 
 		slow = lock_sock_fast(tcp_sk);
 		if (tcp_sk->sk_state != TCP_CLOSE) {
-			tcp_send_active_reset(tcp_sk, GFP_ATOMIC);
+			mptcp_send_active_reset_reason(tcp_sk);
 			tcp_set_state(tcp_sk, TCP_CLOSE);
 		}
 		unlock_sock_fast(tcp_sk, slow);
@@ -2793,6 +2798,9 @@ static void __mptcp_init_sock(struct sock *sk)
 	WRITE_ONCE(msk->allow_infinite_fallback, true);
 	msk->recovery = false;
 	msk->subflow_id = 1;
+	msk->last_data_sent = tcp_jiffies32;
+	msk->last_data_recv = tcp_jiffies32;
+	msk->last_ack_recv = tcp_jiffies32;
 
 	mptcp_pm_data_init(msk);
 
@@ -2806,7 +2814,8 @@ 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);
+	strscpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name,
+		sizeof(mptcp_sk(sk)->ca_name));
 
 	/* no need to keep a reference to the ops, the name will suffice */
 	tcp_cleanup_congestion_control(sk);
@@ -3879,11 +3888,10 @@ unlock:
 }
 
 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
-			       int flags, bool kern)
+			       struct proto_accept_arg *arg)
 {
 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
 	struct sock *ssk, *newsk;
-	int err;
 
 	pr_debug("msk=%p", msk);
 
@@ -3895,9 +3903,9 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
 		return -EINVAL;
 
 	pr_debug("ssk=%p, listener=%p", ssk, mptcp_subflow_ctx(ssk));
-	newsk = inet_csk_accept(ssk, flags, &err, kern);
+	newsk = inet_csk_accept(ssk, arg);
 	if (!newsk)
-		return err;
+		return arg->err;
 
 	pr_debug("newsk=%p, subflow is mptcp=%d", newsk, sk_is_mptcp(newsk));
 	if (sk_is_mptcp(newsk)) {
@@ -3918,7 +3926,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
 		newsk = new_mptcp_sock;
 		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
 
-		newsk->sk_kern_sock = kern;
+		newsk->sk_kern_sock = arg->kern;
 		lock_sock(newsk);
 		__inet_accept(sock, newsock, newsk);
 
@@ -3947,7 +3955,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
 		}
 	} else {
 tcpfallback:
-		newsk->sk_kern_sock = kern;
+		newsk->sk_kern_sock = arg->kern;
 		lock_sock(newsk);
 		__inet_accept(sock, newsock, newsk);
 		/* we are being invoked after accepting a non-mp-capable
@@ -4167,7 +4175,7 @@ int __init mptcp_proto_v6_init(void)
 	int err;
 
 	mptcp_v6_prot = mptcp_prot;
-	strcpy(mptcp_v6_prot.name, "MPTCPv6");
+	strscpy(mptcp_v6_prot.name, "MPTCPv6", sizeof(mptcp_v6_prot.name));
 	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);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 9d1ee19949..7aa47e2dd5 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -12,8 +12,7 @@
 #include <net/inet_connection_sock.h>
 #include <uapi/linux/mptcp.h>
 #include <net/genetlink.h>
-
-#include "mptcp_pm_gen.h"
+#include <net/rstreason.h>
 
 #define MPTCP_SUPPORTED_VERSION	1
 
@@ -282,6 +281,9 @@ struct mptcp_sock {
 	u64		bytes_acked;
 	u64		snd_una;
 	u64		wnd_end;
+	u32		last_data_sent;
+	u32		last_data_recv;
+	u32		last_ack_recv;
 	unsigned long	timer_ival;
 	u32		token;
 	int		rmem_released;
@@ -561,7 +563,7 @@ struct mptcp_subflow_context {
 static inline struct mptcp_subflow_context *
 mptcp_subflow_ctx(const struct sock *sk)
 {
-	struct inet_connection_sock *icsk = inet_csk(sk);
+	const struct inet_connection_sock *icsk = inet_csk(sk);
 
 	/* Use RCU on icsk_ulp_data only for sock diag code */
 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
@@ -581,6 +583,43 @@ mptcp_subflow_ctx_reset(struct mptcp_subflow_context *subflow)
 	WRITE_ONCE(subflow->local_id, -1);
 }
 
+/* Convert reset reasons in MPTCP to enum sk_rst_reason type */
+static inline enum sk_rst_reason
+sk_rst_convert_mptcp_reason(u32 reason)
+{
+	switch (reason) {
+	case MPTCP_RST_EUNSPEC:
+		return SK_RST_REASON_MPTCP_RST_EUNSPEC;
+	case MPTCP_RST_EMPTCP:
+		return SK_RST_REASON_MPTCP_RST_EMPTCP;
+	case MPTCP_RST_ERESOURCE:
+		return SK_RST_REASON_MPTCP_RST_ERESOURCE;
+	case MPTCP_RST_EPROHIBIT:
+		return SK_RST_REASON_MPTCP_RST_EPROHIBIT;
+	case MPTCP_RST_EWQ2BIG:
+		return SK_RST_REASON_MPTCP_RST_EWQ2BIG;
+	case MPTCP_RST_EBADPERF:
+		return SK_RST_REASON_MPTCP_RST_EBADPERF;
+	case MPTCP_RST_EMIDDLEBOX:
+		return SK_RST_REASON_MPTCP_RST_EMIDDLEBOX;
+	default:
+		/* It should not happen, or else errors may occur
+		 * in MPTCP layer
+		 */
+		return SK_RST_REASON_ERROR;
+	}
+}
+
+static inline void
+mptcp_send_active_reset_reason(struct sock *sk)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+	enum sk_rst_reason reason;
+
+	reason = sk_rst_convert_mptcp_reason(subflow->reset_reason);
+	tcp_send_active_reset(sk, GFP_ATOMIC, reason);
+}
+
 static inline u64
 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
 {
@@ -645,6 +684,7 @@ unsigned int mptcp_stale_loss_cnt(const struct net *net);
 unsigned int mptcp_close_timeout(const struct sock *sk);
 int mptcp_get_pm_type(const struct net *net);
 const char *mptcp_get_scheduler(const struct net *net);
+void mptcp_get_available_schedulers(char *buf, size_t maxlen);
 void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
 				       struct mptcp_subflow_context *subflow,
 				       const struct mptcp_options_received *mp_opt);
diff --git a/net/mptcp/sched.c b/net/mptcp/sched.c
index 4ab0693c06..4a7fd0508a 100644
--- a/net/mptcp/sched.c
+++ b/net/mptcp/sched.c
@@ -51,6 +51,28 @@ struct mptcp_sched_ops *mptcp_sched_find(const char *name)
 	return ret;
 }
 
+/* Build string with list of available scheduler values.
+ * Similar to tcp_get_available_congestion_control()
+ */
+void mptcp_get_available_schedulers(char *buf, size_t maxlen)
+{
+	struct mptcp_sched_ops *sched;
+	size_t offs = 0;
+
+	rcu_read_lock();
+	spin_lock(&mptcp_sched_list_lock);
+	list_for_each_entry_rcu(sched, &mptcp_sched_list, list) {
+		offs += snprintf(buf + offs, maxlen - offs,
+				 "%s%s",
+				 offs == 0 ? "" : " ", sched->name);
+
+		if (WARN_ON_ONCE(offs >= maxlen))
+			break;
+	}
+	spin_unlock(&mptcp_sched_list_lock);
+	rcu_read_unlock();
+}
+
 int mptcp_register_scheduler(struct mptcp_sched_ops *sched)
 {
 	if (!sched->get_subflow)
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 19ee684f9e..f9a4fb17b5 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -616,7 +616,7 @@ static int mptcp_setsockopt_sol_tcp_congestion(struct mptcp_sock *msk, sockptr_t
 	}
 
 	if (ret == 0)
-		strcpy(msk->ca_name, name);
+		strscpy(msk->ca_name, name, sizeof(msk->ca_name));
 
 	release_sock(sk);
 	return ret;
@@ -937,6 +937,7 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 	struct sock *sk = (struct sock *)msk;
 	u32 flags = 0;
 	bool slow;
+	u32 now;
 
 	memset(info, 0, sizeof(*info));
 
@@ -965,11 +966,6 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 	if (READ_ONCE(msk->can_ack))
 		flags |= MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED;
 	info->mptcpi_flags = flags;
-	mptcp_data_lock(sk);
-	info->mptcpi_snd_una = msk->snd_una;
-	info->mptcpi_rcv_nxt = msk->ack_seq;
-	info->mptcpi_bytes_acked = msk->bytes_acked;
-	mptcp_data_unlock(sk);
 
 	slow = lock_sock_fast(sk);
 	info->mptcpi_csum_enabled = READ_ONCE(msk->csum_enabled);
@@ -981,7 +977,17 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 	info->mptcpi_bytes_retrans = msk->bytes_retrans;
 	info->mptcpi_subflows_total = info->mptcpi_subflows +
 		__mptcp_has_initial_subflow(msk);
+	now = tcp_jiffies32;
+	info->mptcpi_last_data_sent = jiffies_to_msecs(now - msk->last_data_sent);
+	info->mptcpi_last_data_recv = jiffies_to_msecs(now - msk->last_data_recv);
 	unlock_sock_fast(sk, slow);
+
+	mptcp_data_lock(sk);
+	info->mptcpi_last_ack_recv = jiffies_to_msecs(now - msk->last_ack_recv);
+	info->mptcpi_snd_una = msk->snd_una;
+	info->mptcpi_rcv_nxt = msk->ack_seq;
+	info->mptcpi_bytes_acked = msk->bytes_acked;
+	mptcp_data_unlock(sk);
 }
 EXPORT_SYMBOL_GPL(mptcp_diag_fill_info);
 
@@ -993,6 +999,10 @@ static int mptcp_getsockopt_info(struct mptcp_sock *msk, char __user *optval, in
 	if (get_user(len, optlen))
 		return -EFAULT;
 
+	/* When used only to check if a fallback to TCP happened. */
+	if (len == 0)
+		return 0;
+
 	len = min_t(unsigned int, len, sizeof(struct mptcp_info));
 
 	mptcp_diag_fill_info(msk, &m_info);
@@ -1395,6 +1405,8 @@ static int mptcp_getsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
 					    READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_keepalive_probes));
 	case TCP_NOTSENT_LOWAT:
 		return mptcp_put_int_option(msk, optval, optlen, msk->notsent_lowat);
+	case TCP_IS_MPTCP:
+		return mptcp_put_int_option(msk, optval, optlen, 1);
 	}
 	return -EOPNOTSUPP;
 }
@@ -1579,7 +1591,7 @@ int mptcp_set_rcvlowat(struct sock *sk, int val)
 
 		slow = lock_sock_fast(ssk);
 		WRITE_ONCE(ssk->sk_rcvbuf, space);
-		tcp_sk(ssk)->window_clamp = val;
+		WRITE_ONCE(tcp_sk(ssk)->window_clamp, val);
 		unlock_sock_fast(ssk, slow);
 	}
 	return 0;
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 6042a47da6..612c38570a 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -20,6 +20,7 @@
 #include <net/transp_v6.h>
 #endif
 #include <net/mptcp.h>
+
 #include "protocol.h"
 #include "mib.h"
 
@@ -150,8 +151,10 @@ static int subflow_check_req(struct request_sock *req,
 	/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
 	 * TCP option space.
 	 */
-	if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info))
+	if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info)) {
+		subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP);
 		return -EINVAL;
+	}
 #endif
 
 	mptcp_get_options(skb, &mp_opt);
@@ -219,6 +222,7 @@ again:
 				 ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport));
 			if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) {
 				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTSYNRX);
+				subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
 				return -EPERM;
 			}
 			SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTSYNRX);
@@ -227,10 +231,12 @@ again:
 		subflow_req_create_thmac(subflow_req);
 
 		if (unlikely(req->syncookie)) {
-			if (mptcp_can_accept_new_subflow(subflow_req->msk))
-				subflow_init_req_cookie_join_save(subflow_req, skb);
-			else
+			if (!mptcp_can_accept_new_subflow(subflow_req->msk)) {
+				subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
 				return -EPERM;
+			}
+
+			subflow_init_req_cookie_join_save(subflow_req, skb);
 		}
 
 		pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token,
@@ -281,10 +287,21 @@ int mptcp_subflow_init_cookie_req(struct request_sock *req,
 }
 EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req);
 
+static enum sk_rst_reason mptcp_get_rst_reason(const struct sk_buff *skb)
+{
+	const struct mptcp_ext *mpext = mptcp_get_ext(skb);
+
+	if (!mpext)
+		return SK_RST_REASON_NOT_SPECIFIED;
+
+	return sk_rst_convert_mptcp_reason(mpext->reset_reason);
+}
+
 static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
 					      struct sk_buff *skb,
 					      struct flowi *fl,
-					      struct request_sock *req)
+					      struct request_sock *req,
+					      u32 tw_isn)
 {
 	struct dst_entry *dst;
 	int err;
@@ -292,7 +309,7 @@ static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
 	tcp_rsk(req)->is_mptcp = 1;
 	subflow_init_req(req, sk);
 
-	dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req);
+	dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req, tw_isn);
 	if (!dst)
 		return NULL;
 
@@ -302,7 +319,8 @@ static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
 
 	dst_release(dst);
 	if (!req->syncookie)
-		tcp_request_sock_ops.send_reset(sk, skb);
+		tcp_request_sock_ops.send_reset(sk, skb,
+						mptcp_get_rst_reason(skb));
 	return NULL;
 }
 
@@ -351,7 +369,8 @@ static int subflow_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
 					      struct sk_buff *skb,
 					      struct flowi *fl,
-					      struct request_sock *req)
+					      struct request_sock *req,
+					      u32 tw_isn)
 {
 	struct dst_entry *dst;
 	int err;
@@ -359,7 +378,7 @@ static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
 	tcp_rsk(req)->is_mptcp = 1;
 	subflow_init_req(req, sk);
 
-	dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req);
+	dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req, tw_isn);
 	if (!dst)
 		return NULL;
 
@@ -369,7 +388,8 @@ static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
 
 	dst_release(dst);
 	if (!req->syncookie)
-		tcp6_request_sock_ops.send_reset(sk, skb);
+		tcp6_request_sock_ops.send_reset(sk, skb,
+						 mptcp_get_rst_reason(skb));
 	return NULL;
 }
 #endif
@@ -405,7 +425,7 @@ void mptcp_subflow_reset(struct sock *ssk)
 	/* must hold: tcp_done() could drop last reference on parent */
 	sock_hold(sk);
 
-	tcp_send_active_reset(ssk, GFP_ATOMIC);
+	mptcp_send_active_reset_reason(ssk);
 	tcp_done(ssk);
 	if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags))
 		mptcp_schedule_work(sk);
@@ -774,6 +794,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 	struct mptcp_subflow_request_sock *subflow_req;
 	struct mptcp_options_received mp_opt;
 	bool fallback, fallback_is_fatal;
+	enum sk_rst_reason reason;
 	struct mptcp_sock *owner;
 	struct sock *child;
 
@@ -873,13 +894,18 @@ create_child:
 					 ntohs(inet_sk((struct sock *)owner)->inet_sport));
 				if (!mptcp_pm_sport_in_anno_list(owner, sk)) {
 					SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTACKRX);
+					subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
 					goto dispose_child;
 				}
 				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTACKRX);
 			}
 
-			if (!mptcp_finish_join(child))
+			if (!mptcp_finish_join(child)) {
+				struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(child);
+
+				subflow_add_reset_reason(skb, subflow->reset_reason);
 				goto dispose_child;
+			}
 
 			SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX);
 			tcp_rsk(req)->drop_req = true;
@@ -887,7 +913,7 @@ create_child:
 	}
 
 	/* check for expected invariant - should never trigger, just help
-	 * catching eariler subtle bugs
+	 * catching earlier subtle bugs
 	 */
 	WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp &&
 		     (!mptcp_subflow_ctx(child) ||
@@ -899,7 +925,8 @@ dispose_child:
 	tcp_rsk(req)->drop_req = true;
 	inet_csk_prepare_for_destroy_sock(child);
 	tcp_done(child);
-	req->rsk_ops->send_reset(sk, skb);
+	reason = mptcp_get_rst_reason(skb);
+	req->rsk_ops->send_reset(sk, skb, reason);
 
 	/* The last child reference will be released by the caller */
 	return child;
@@ -1092,6 +1119,8 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
 	}
 
 	if (mpext->data_fin == 1) {
+		u64 data_fin_seq;
+
 		if (data_len == 1) {
 			bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq,
 								 mpext->dsn64);
@@ -1104,26 +1133,26 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
 				 */
 				skb_ext_del(skb, SKB_EXT_MPTCP);
 				return MAPPING_OK;
-			} else {
-				if (updated)
-					mptcp_schedule_work((struct sock *)msk);
-
-				return MAPPING_DATA_FIN;
 			}
-		} else {
-			u64 data_fin_seq = mpext->data_seq + data_len - 1;
 
-			/* If mpext->data_seq is a 32-bit value, data_fin_seq
-			 * must also be limited to 32 bits.
-			 */
-			if (!mpext->dsn64)
-				data_fin_seq &= GENMASK_ULL(31, 0);
+			if (updated)
+				mptcp_schedule_work((struct sock *)msk);
 
-			mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64);
-			pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d",
-				 data_fin_seq, mpext->dsn64);
+			return MAPPING_DATA_FIN;
 		}
 
+		data_fin_seq = mpext->data_seq + data_len - 1;
+
+		/* If mpext->data_seq is a 32-bit value, data_fin_seq must also
+		 * be limited to 32 bits.
+		 */
+		if (!mpext->dsn64)
+			data_fin_seq &= GENMASK_ULL(31, 0);
+
+		mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64);
+		pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d",
+			 data_fin_seq, mpext->dsn64);
+
 		/* Adjust for DATA_FIN using 1 byte of sequence space */
 		data_len--;
 	}
@@ -1234,7 +1263,7 @@ static void mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk)
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 	unsigned long fail_tout;
 
-	/* greceful failure can happen only on the MPC subflow */
+	/* graceful failure can happen only on the MPC subflow */
 	if (WARN_ON_ONCE(ssk != READ_ONCE(msk->first)))
 		return;
 
@@ -1336,7 +1365,7 @@ reset:
 			tcp_set_state(ssk, TCP_CLOSE);
 			while ((skb = skb_peek(&ssk->sk_receive_queue)))
 				sk_eat_skb(ssk, skb);
-			tcp_send_active_reset(ssk, GFP_ATOMIC);
+			mptcp_send_active_reset_reason(ssk);
 			WRITE_ONCE(subflow->data_avail, false);
 			return false;
 		}