Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

5 files changed, 4655 insertions, 0 deletions

diff --git a/net/bluetooth/rfcomm/Kconfig b/net/bluetooth/rfcomm/Kconfig
new file mode 100644
index 000000000..e7af2d565
--- /dev/null
+++ b/net/bluetooth/rfcomm/Kconfig
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config BT_RFCOMM
+	tristate "RFCOMM protocol support"
+	depends on BT && BT_BREDR
+	help
+	  RFCOMM provides connection oriented stream transport.  RFCOMM
+	  support is required for Dialup Networking, OBEX and other Bluetooth
+	  applications.
+
+	  Say Y here to compile RFCOMM support into the kernel or say M to
+	  compile it as module (rfcomm).
+
+config BT_RFCOMM_TTY
+	bool "RFCOMM TTY support"
+	depends on BT_RFCOMM
+	depends on TTY
+	help
+	  This option enables TTY emulation support for RFCOMM channels.
+
diff --git a/net/bluetooth/rfcomm/Makefile b/net/bluetooth/rfcomm/Makefile
new file mode 100644
index 000000000..15f909f40
--- /dev/null
+++ b/net/bluetooth/rfcomm/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the Linux Bluetooth RFCOMM layer.
+#
+
+obj-$(CONFIG_BT_RFCOMM) += rfcomm.o
+
+rfcomm-y			:= core.o sock.o
+rfcomm-$(CONFIG_BT_RFCOMM_TTY)	+= tty.o
+
+CONTEXT_ANALYSIS := y
diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c
new file mode 100644
index 000000000..f7463f092
--- /dev/null
+++ b/net/bluetooth/rfcomm/core.c
@@ -0,0 +1,2369 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+   RFCOMM implementation for Linux Bluetooth stack (BlueZ).
+   Copyright (C) 2002 Maxim Krasnyansky <maxk@qualcomm.com>
+   Copyright (C) 2002 Marcel Holtmann <marcel@holtmann.org>
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
+   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
+   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
+   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
+   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
+   SOFTWARE IS DISCLAIMED.
+*/
+
+/*
+ * Bluetooth RFCOMM core.
+ */
+
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/kthread.h>
+#include <linux/unaligned.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+#include <net/bluetooth/l2cap.h>
+#include <net/bluetooth/rfcomm.h>
+
+#include <trace/events/sock.h>
+
+#define VERSION "1.11"
+
+static bool disable_cfc;
+static bool l2cap_ertm;
+static int channel_mtu = -1;
+
+static struct task_struct *rfcomm_thread;
+
+static DEFINE_MUTEX(rfcomm_mutex);
+#define rfcomm_lock()	mutex_lock(&rfcomm_mutex)
+#define rfcomm_unlock()	mutex_unlock(&rfcomm_mutex)
+
+
+static LIST_HEAD(session_list);
+
+static int rfcomm_send_frame(struct rfcomm_session *s, u8 *data, int len);
+static int rfcomm_send_sabm(struct rfcomm_session *s, u8 dlci);
+static int rfcomm_send_disc(struct rfcomm_session *s, u8 dlci);
+static int rfcomm_queue_disc(struct rfcomm_dlc *d);
+static int rfcomm_send_nsc(struct rfcomm_session *s, int cr, u8 type);
+static int rfcomm_send_pn(struct rfcomm_session *s, int cr, struct rfcomm_dlc *d);
+static int rfcomm_send_msc(struct rfcomm_session *s, int cr, u8 dlci, u8 v24_sig);
+static int rfcomm_send_test(struct rfcomm_session *s, int cr, u8 *pattern, int len);
+static int rfcomm_send_credits(struct rfcomm_session *s, u8 addr, u8 credits);
+static void rfcomm_make_uih(struct sk_buff *skb, u8 addr);
+
+static void rfcomm_process_connect(struct rfcomm_session *s);
+
+static struct rfcomm_session *rfcomm_session_create(bdaddr_t *src,
+							bdaddr_t *dst,
+							u8 sec_level,
+							int *err);
+static struct rfcomm_session *rfcomm_session_get(bdaddr_t *src, bdaddr_t *dst);
+static struct rfcomm_session *rfcomm_session_del(struct rfcomm_session *s);
+
+/* ---- RFCOMM frame parsing macros ---- */
+#define __get_dlci(b)     ((b & 0xfc) >> 2)
+#define __get_type(b)     ((b & 0xef))
+
+#define __test_ea(b)      ((b & 0x01))
+#define __test_cr(b)      (!!(b & 0x02))
+#define __test_pf(b)      (!!(b & 0x10))
+
+#define __session_dir(s)  ((s)->initiator ? 0x00 : 0x01)
+
+#define __addr(cr, dlci)       (((dlci & 0x3f) << 2) | (cr << 1) | 0x01)
+#define __ctrl(type, pf)       (((type & 0xef) | (pf << 4)))
+#define __dlci(dir, chn)       (((chn & 0x1f) << 1) | dir)
+#define __srv_channel(dlci)    (dlci >> 1)
+
+#define __len8(len)       (((len) << 1) | 1)
+#define __len16(len)      ((len) << 1)
+
+/* MCC macros */
+#define __mcc_type(cr, type)   (((type << 2) | (cr << 1) | 0x01))
+#define __get_mcc_type(b) ((b & 0xfc) >> 2)
+#define __get_mcc_len(b)  ((b & 0xfe) >> 1)
+
+/* RPN macros */
+#define __rpn_line_settings(data, stop, parity)  ((data & 0x3) | ((stop & 0x1) << 2) | ((parity & 0x7) << 3))
+#define __get_rpn_data_bits(line) ((line) & 0x3)
+#define __get_rpn_stop_bits(line) (((line) >> 2) & 0x1)
+#define __get_rpn_parity(line)    (((line) >> 3) & 0x7)
+
+static DECLARE_WAIT_QUEUE_HEAD(rfcomm_wq);
+
+static void rfcomm_schedule(void)
+{
+	wake_up_all(&rfcomm_wq);
+}
+
+/* ---- RFCOMM FCS computation ---- */
+
+/* reversed, 8-bit, poly=0x07 */
+static unsigned char rfcomm_crc_table[256] = {
+	0x00, 0x91, 0xe3, 0x72, 0x07, 0x96, 0xe4, 0x75,
+	0x0e, 0x9f, 0xed, 0x7c, 0x09, 0x98, 0xea, 0x7b,
+	0x1c, 0x8d, 0xff, 0x6e, 0x1b, 0x8a, 0xf8, 0x69,
+	0x12, 0x83, 0xf1, 0x60, 0x15, 0x84, 0xf6, 0x67,
+
+	0x38, 0xa9, 0xdb, 0x4a, 0x3f, 0xae, 0xdc, 0x4d,
+	0x36, 0xa7, 0xd5, 0x44, 0x31, 0xa0, 0xd2, 0x43,
+	0x24, 0xb5, 0xc7, 0x56, 0x23, 0xb2, 0xc0, 0x51,
+	0x2a, 0xbb, 0xc9, 0x58, 0x2d, 0xbc, 0xce, 0x5f,
+
+	0x70, 0xe1, 0x93, 0x02, 0x77, 0xe6, 0x94, 0x05,
+	0x7e, 0xef, 0x9d, 0x0c, 0x79, 0xe8, 0x9a, 0x0b,
+	0x6c, 0xfd, 0x8f, 0x1e, 0x6b, 0xfa, 0x88, 0x19,
+	0x62, 0xf3, 0x81, 0x10, 0x65, 0xf4, 0x86, 0x17,
+
+	0x48, 0xd9, 0xab, 0x3a, 0x4f, 0xde, 0xac, 0x3d,
+	0x46, 0xd7, 0xa5, 0x34, 0x41, 0xd0, 0xa2, 0x33,
+	0x54, 0xc5, 0xb7, 0x26, 0x53, 0xc2, 0xb0, 0x21,
+	0x5a, 0xcb, 0xb9, 0x28, 0x5d, 0xcc, 0xbe, 0x2f,
+
+	0xe0, 0x71, 0x03, 0x92, 0xe7, 0x76, 0x04, 0x95,
+	0xee, 0x7f, 0x0d, 0x9c, 0xe9, 0x78, 0x0a, 0x9b,
+	0xfc, 0x6d, 0x1f, 0x8e, 0xfb, 0x6a, 0x18, 0x89,
+	0xf2, 0x63, 0x11, 0x80, 0xf5, 0x64, 0x16, 0x87,
+
+	0xd8, 0x49, 0x3b, 0xaa, 0xdf, 0x4e, 0x3c, 0xad,
+	0xd6, 0x47, 0x35, 0xa4, 0xd1, 0x40, 0x32, 0xa3,
+	0xc4, 0x55, 0x27, 0xb6, 0xc3, 0x52, 0x20, 0xb1,
+	0xca, 0x5b, 0x29, 0xb8, 0xcd, 0x5c, 0x2e, 0xbf,
+
+	0x90, 0x01, 0x73, 0xe2, 0x97, 0x06, 0x74, 0xe5,
+	0x9e, 0x0f, 0x7d, 0xec, 0x99, 0x08, 0x7a, 0xeb,
+	0x8c, 0x1d, 0x6f, 0xfe, 0x8b, 0x1a, 0x68, 0xf9,
+	0x82, 0x13, 0x61, 0xf0, 0x85, 0x14, 0x66, 0xf7,
+
+	0xa8, 0x39, 0x4b, 0xda, 0xaf, 0x3e, 0x4c, 0xdd,
+	0xa6, 0x37, 0x45, 0xd4, 0xa1, 0x30, 0x42, 0xd3,
+	0xb4, 0x25, 0x57, 0xc6, 0xb3, 0x22, 0x50, 0xc1,
+	0xba, 0x2b, 0x59, 0xc8, 0xbd, 0x2c, 0x5e, 0xcf
+};
+
+/* CRC on 2 bytes */
+#define __crc(data) (rfcomm_crc_table[rfcomm_crc_table[0xff ^ data[0]] ^ data[1]])
+
+/* FCS on 2 bytes */
+static inline u8 __fcs(u8 *data)
+{
+	return 0xff - __crc(data);
+}
+
+/* FCS on 3 bytes */
+static inline u8 __fcs2(u8 *data)
+{
+	return 0xff - rfcomm_crc_table[__crc(data) ^ data[2]];
+}
+
+/* Check FCS */
+static inline int __check_fcs(u8 *data, int type, u8 fcs)
+{
+	u8 f = __crc(data);
+
+	if (type != RFCOMM_UIH)
+		f = rfcomm_crc_table[f ^ data[2]];
+
+	return rfcomm_crc_table[f ^ fcs] != 0xcf;
+}
+
+/* ---- L2CAP callbacks ---- */
+static void rfcomm_l2state_change(struct sock *sk)
+{
+	BT_DBG("%p state %d", sk, sk->sk_state);
+	rfcomm_schedule();
+}
+
+static void rfcomm_l2data_ready(struct sock *sk)
+{
+	trace_sk_data_ready(sk);
+
+	BT_DBG("%p", sk);
+	rfcomm_schedule();
+}
+
+static int rfcomm_l2sock_create(struct socket **sock)
+{
+	int err;
+
+	BT_DBG("");
+
+	err = sock_create_kern(&init_net, PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP, sock);
+	if (!err) {
+		struct sock *sk = (*sock)->sk;
+		sk->sk_data_ready   = rfcomm_l2data_ready;
+		sk->sk_state_change = rfcomm_l2state_change;
+	}
+	return err;
+}
+
+static int rfcomm_check_security(struct rfcomm_dlc *d)
+{
+	struct sock *sk = d->session->sock->sk;
+	struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
+
+	__u8 auth_type;
+
+	switch (d->sec_level) {
+	case BT_SECURITY_HIGH:
+	case BT_SECURITY_FIPS:
+		auth_type = HCI_AT_GENERAL_BONDING_MITM;
+		break;
+	case BT_SECURITY_MEDIUM:
+		auth_type = HCI_AT_GENERAL_BONDING;
+		break;
+	default:
+		auth_type = HCI_AT_NO_BONDING;
+		break;
+	}
+
+	return hci_conn_security(conn->hcon, d->sec_level, auth_type,
+				 d->out);
+}
+
+static void rfcomm_session_timeout(struct timer_list *t)
+{
+	struct rfcomm_session *s = timer_container_of(s, t, timer);
+
+	BT_DBG("session %p state %ld", s, s->state);
+
+	set_bit(RFCOMM_TIMED_OUT, &s->flags);
+	rfcomm_schedule();
+}
+
+static void rfcomm_session_set_timer(struct rfcomm_session *s, long timeout)
+{
+	BT_DBG("session %p state %ld timeout %ld", s, s->state, timeout);
+
+	mod_timer(&s->timer, jiffies + timeout);
+}
+
+static void rfcomm_session_clear_timer(struct rfcomm_session *s)
+{
+	BT_DBG("session %p state %ld", s, s->state);
+
+	timer_delete_sync(&s->timer);
+}
+
+/* ---- RFCOMM DLCs ---- */
+static void rfcomm_dlc_timeout(struct timer_list *t)
+{
+	struct rfcomm_dlc *d = timer_container_of(d, t, timer);
+
+	BT_DBG("dlc %p state %ld", d, d->state);
+
+	set_bit(RFCOMM_TIMED_OUT, &d->flags);
+	rfcomm_dlc_put(d);
+	rfcomm_schedule();
+}
+
+static void rfcomm_dlc_set_timer(struct rfcomm_dlc *d, long timeout)
+{
+	BT_DBG("dlc %p state %ld timeout %ld", d, d->state, timeout);
+
+	if (!mod_timer(&d->timer, jiffies + timeout))
+		rfcomm_dlc_hold(d);
+}
+
+static void rfcomm_dlc_clear_timer(struct rfcomm_dlc *d)
+{
+	BT_DBG("dlc %p state %ld", d, d->state);
+
+	if (timer_delete(&d->timer))
+		rfcomm_dlc_put(d);
+}
+
+static void rfcomm_dlc_clear_state(struct rfcomm_dlc *d)
+{
+	BT_DBG("%p", d);
+
+	d->state      = BT_OPEN;
+	d->flags      = 0;
+	d->mscex      = 0;
+	d->sec_level  = BT_SECURITY_LOW;
+	d->mtu        = RFCOMM_DEFAULT_MTU;
+	d->v24_sig    = RFCOMM_V24_RTC | RFCOMM_V24_RTR | RFCOMM_V24_DV;
+
+	d->cfc        = RFCOMM_CFC_DISABLED;
+	d->rx_credits = RFCOMM_DEFAULT_CREDITS;
+}
+
+struct rfcomm_dlc *rfcomm_dlc_alloc(gfp_t prio)
+{
+	struct rfcomm_dlc *d = kzalloc_obj(*d, prio);
+
+	if (!d)
+		return NULL;
+
+	timer_setup(&d->timer, rfcomm_dlc_timeout, 0);
+
+	skb_queue_head_init(&d->tx_queue);
+	mutex_init(&d->lock);
+	refcount_set(&d->refcnt, 1);
+
+	rfcomm_dlc_clear_state(d);
+
+	BT_DBG("%p", d);
+
+	return d;
+}
+
+void rfcomm_dlc_free(struct rfcomm_dlc *d)
+{
+	BT_DBG("%p", d);
+
+	skb_queue_purge(&d->tx_queue);
+	kfree(d);
+}
+
+static void rfcomm_dlc_link(struct rfcomm_session *s, struct rfcomm_dlc *d)
+{
+	BT_DBG("dlc %p session %p", d, s);
+
+	rfcomm_session_clear_timer(s);
+	rfcomm_dlc_hold(d);
+	list_add(&d->list, &s->dlcs);
+	d->session = s;
+}
+
+static void rfcomm_dlc_unlink(struct rfcomm_dlc *d)
+{
+	struct rfcomm_session *s = d->session;
+
+	BT_DBG("dlc %p refcnt %d session %p", d, refcount_read(&d->refcnt), s);
+
+	list_del(&d->list);
+	d->session = NULL;
+	rfcomm_dlc_put(d);
+
+	if (list_empty(&s->dlcs))
+		rfcomm_session_set_timer(s, RFCOMM_IDLE_TIMEOUT);
+}
+
+static struct rfcomm_dlc *rfcomm_dlc_get(struct rfcomm_session *s, u8 dlci)
+{
+	struct rfcomm_dlc *d;
+
+	list_for_each_entry(d, &s->dlcs, list)
+		if (d->dlci == dlci)
+			return d;
+
+	return NULL;
+}
+
+static int rfcomm_check_channel(u8 channel)
+{
+	return channel < 1 || channel > 30;
+}
+
+static int __rfcomm_dlc_open(struct rfcomm_dlc *d, bdaddr_t *src, bdaddr_t *dst, u8 channel)
+{
+	struct rfcomm_session *s;
+	int err = 0;
+	u8 dlci;
+
+	BT_DBG("dlc %p state %ld %pMR -> %pMR channel %d",
+	       d, d->state, src, dst, channel);
+
+	if (rfcomm_check_channel(channel))
+		return -EINVAL;
+
+	if (d->state != BT_OPEN && d->state != BT_CLOSED)
+		return 0;
+
+	s = rfcomm_session_get(src, dst);
+	if (!s) {
+		s = rfcomm_session_create(src, dst, d->sec_level, &err);
+		if (!s)
+			return err;
+	}
+
+	dlci = __dlci(__session_dir(s), channel);
+
+	/* Check if DLCI already exists */
+	if (rfcomm_dlc_get(s, dlci))
+		return -EBUSY;
+
+	rfcomm_dlc_clear_state(d);
+
+	d->dlci     = dlci;
+	d->addr     = __addr(s->initiator, dlci);
+	d->priority = 7;
+
+	d->state = BT_CONFIG;
+	rfcomm_dlc_link(s, d);
+
+	d->out = 1;
+
+	d->mtu = s->mtu;
+	d->cfc = (s->cfc == RFCOMM_CFC_UNKNOWN) ? 0 : s->cfc;
+
+	if (s->state == BT_CONNECTED) {
+		if (rfcomm_check_security(d))
+			rfcomm_send_pn(s, 1, d);
+		else
+			set_bit(RFCOMM_AUTH_PENDING, &d->flags);
+	}
+
+	rfcomm_dlc_set_timer(d, RFCOMM_CONN_TIMEOUT);
+
+	return 0;
+}
+
+int rfcomm_dlc_open(struct rfcomm_dlc *d, bdaddr_t *src, bdaddr_t *dst, u8 channel)
+{
+	int r;
+
+	rfcomm_lock();
+
+	r = __rfcomm_dlc_open(d, src, dst, channel);
+
+	rfcomm_unlock();
+	return r;
+}
+
+static void __rfcomm_dlc_disconn(struct rfcomm_dlc *d)
+{
+	struct rfcomm_session *s = d->session;
+
+	d->state = BT_DISCONN;
+	if (skb_queue_empty(&d->tx_queue)) {
+		rfcomm_send_disc(s, d->dlci);
+		rfcomm_dlc_set_timer(d, RFCOMM_DISC_TIMEOUT);
+	} else {
+		rfcomm_queue_disc(d);
+		rfcomm_dlc_set_timer(d, RFCOMM_DISC_TIMEOUT * 2);
+	}
+}
+
+static int __rfcomm_dlc_close(struct rfcomm_dlc *d, int err)
+{
+	struct rfcomm_session *s = d->session;
+	if (!s)
+		return 0;
+
+	BT_DBG("dlc %p state %ld dlci %d err %d session %p",
+			d, d->state, d->dlci, err, s);
+
+	switch (d->state) {
+	case BT_CONNECT:
+	case BT_CONFIG:
+	case BT_OPEN:
+	case BT_CONNECT2:
+		if (test_and_clear_bit(RFCOMM_DEFER_SETUP, &d->flags)) {
+			set_bit(RFCOMM_AUTH_REJECT, &d->flags);
+			rfcomm_schedule();
+			return 0;
+		}
+	}
+
+	switch (d->state) {
+	case BT_CONNECT:
+	case BT_CONNECTED:
+		__rfcomm_dlc_disconn(d);
+		break;
+
+	case BT_CONFIG:
+		if (s->state != BT_BOUND) {
+			__rfcomm_dlc_disconn(d);
+			break;
+		}
+		/* if closing a dlc in a session that hasn't been started,
+		 * just close and unlink the dlc
+		 */
+		fallthrough;
+
+	default:
+		rfcomm_dlc_clear_timer(d);
+
+		rfcomm_dlc_lock(d);
+		d->state = BT_CLOSED;
+		d->state_change(d, err);
+		rfcomm_dlc_unlock(d);
+
+		skb_queue_purge(&d->tx_queue);
+		rfcomm_dlc_unlink(d);
+	}
+
+	return 0;
+}
+
+int rfcomm_dlc_close(struct rfcomm_dlc *d, int err)
+{
+	int r = 0;
+	struct rfcomm_dlc *d_list;
+	struct rfcomm_session *s, *s_list;
+
+	BT_DBG("dlc %p state %ld dlci %d err %d", d, d->state, d->dlci, err);
+
+	rfcomm_lock();
+
+	s = d->session;
+	if (!s)
+		goto no_session;
+
+	/* after waiting on the mutex check the session still exists
+	 * then check the dlc still exists
+	 */
+	list_for_each_entry(s_list, &session_list, list) {
+		if (s_list == s) {
+			list_for_each_entry(d_list, &s->dlcs, list) {
+				if (d_list == d) {
+					r = __rfcomm_dlc_close(d, err);
+					break;
+				}
+			}
+			break;
+		}
+	}
+
+no_session:
+	rfcomm_unlock();
+	return r;
+}
+
+struct rfcomm_dlc *rfcomm_dlc_exists(bdaddr_t *src, bdaddr_t *dst, u8 channel)
+{
+	struct rfcomm_session *s;
+	struct rfcomm_dlc *dlc = NULL;
+	u8 dlci;
+
+	if (rfcomm_check_channel(channel))
+		return ERR_PTR(-EINVAL);
+
+	rfcomm_lock();
+	s = rfcomm_session_get(src, dst);
+	if (s) {
+		dlci = __dlci(__session_dir(s), channel);
+		dlc = rfcomm_dlc_get(s, dlci);
+	}
+	rfcomm_unlock();
+	return dlc;
+}
+
+static int rfcomm_dlc_send_frag(struct rfcomm_dlc *d, struct sk_buff *frag)
+{
+	int len = frag->len;
+
+	BT_DBG("dlc %p mtu %d len %d", d, d->mtu, len);
+
+	if (len > d->mtu)
+		return -EINVAL;
+
+	rfcomm_make_uih(frag, d->addr);
+	__skb_queue_tail(&d->tx_queue, frag);
+
+	return len;
+}
+
+int rfcomm_dlc_send(struct rfcomm_dlc *d, struct sk_buff *skb)
+{
+	unsigned long flags;
+	struct sk_buff *frag, *next;
+	int len;
+
+	if (d->state != BT_CONNECTED)
+		return -ENOTCONN;
+
+	frag = skb_shinfo(skb)->frag_list;
+	skb_shinfo(skb)->frag_list = NULL;
+
+	/* Queue all fragments atomically. */
+	spin_lock_irqsave(&d->tx_queue.lock, flags);
+
+	len = rfcomm_dlc_send_frag(d, skb);
+	if (len < 0 || !frag)
+		goto unlock;
+
+	for (; frag; frag = next) {
+		int ret;
+
+		next = frag->next;
+
+		ret = rfcomm_dlc_send_frag(d, frag);
+		if (ret < 0) {
+			dev_kfree_skb_irq(frag);
+			goto unlock;
+		}
+
+		len += ret;
+	}
+
+unlock:
+	spin_unlock_irqrestore(&d->tx_queue.lock, flags);
+
+	if (len > 0 && !test_bit(RFCOMM_TX_THROTTLED, &d->flags))
+		rfcomm_schedule();
+	return len;
+}
+
+void rfcomm_dlc_send_noerror(struct rfcomm_dlc *d, struct sk_buff *skb)
+{
+	int len = skb->len;
+
+	BT_DBG("dlc %p mtu %d len %d", d, d->mtu, len);
+
+	rfcomm_make_uih(skb, d->addr);
+	skb_queue_tail(&d->tx_queue, skb);
+
+	if (d->state == BT_CONNECTED &&
+	    !test_bit(RFCOMM_TX_THROTTLED, &d->flags))
+		rfcomm_schedule();
+}
+
+void __rfcomm_dlc_throttle(struct rfcomm_dlc *d)
+{
+	BT_DBG("dlc %p state %ld", d, d->state);
+
+	if (!d->cfc) {
+		d->v24_sig |= RFCOMM_V24_FC;
+		set_bit(RFCOMM_MSC_PENDING, &d->flags);
+	}
+	rfcomm_schedule();
+}
+
+void __rfcomm_dlc_unthrottle(struct rfcomm_dlc *d)
+{
+	BT_DBG("dlc %p state %ld", d, d->state);
+
+	if (!d->cfc) {
+		d->v24_sig &= ~RFCOMM_V24_FC;
+		set_bit(RFCOMM_MSC_PENDING, &d->flags);
+	}
+	rfcomm_schedule();
+}
+
+/*
+   Set/get modem status functions use _local_ status i.e. what we report
+   to the other side.
+   Remote status is provided by dlc->modem_status() callback.
+ */
+int rfcomm_dlc_set_modem_status(struct rfcomm_dlc *d, u8 v24_sig)
+{
+	BT_DBG("dlc %p state %ld v24_sig 0x%x",
+			d, d->state, v24_sig);
+
+	if (test_bit(RFCOMM_RX_THROTTLED, &d->flags))
+		v24_sig |= RFCOMM_V24_FC;
+	else
+		v24_sig &= ~RFCOMM_V24_FC;
+
+	d->v24_sig = v24_sig;
+
+	if (!test_and_set_bit(RFCOMM_MSC_PENDING, &d->flags))
+		rfcomm_schedule();
+
+	return 0;
+}
+
+int rfcomm_dlc_get_modem_status(struct rfcomm_dlc *d, u8 *v24_sig)
+{
+	BT_DBG("dlc %p state %ld v24_sig 0x%x",
+			d, d->state, d->v24_sig);
+
+	*v24_sig = d->v24_sig;
+	return 0;
+}
+
+/* ---- RFCOMM sessions ---- */
+static struct rfcomm_session *rfcomm_session_add(struct socket *sock, int state)
+{
+	struct rfcomm_session *s = kzalloc_obj(*s);
+
+	if (!s)
+		return NULL;
+
+	BT_DBG("session %p sock %p", s, sock);
+
+	timer_setup(&s->timer, rfcomm_session_timeout, 0);
+
+	INIT_LIST_HEAD(&s->dlcs);
+	s->state = state;
+	s->sock  = sock;
+
+	s->mtu = RFCOMM_DEFAULT_MTU;
+	s->cfc = disable_cfc ? RFCOMM_CFC_DISABLED : RFCOMM_CFC_UNKNOWN;
+
+	/* Do not increment module usage count for listening sessions.
+	 * Otherwise we won't be able to unload the module. */
+	if (state != BT_LISTEN)
+		if (!try_module_get(THIS_MODULE)) {
+			kfree(s);
+			return NULL;
+		}
+
+	list_add(&s->list, &session_list);
+
+	return s;
+}
+
+static struct rfcomm_session *rfcomm_session_del(struct rfcomm_session *s)
+{
+	int state = s->state;
+
+	BT_DBG("session %p state %ld", s, s->state);
+
+	list_del(&s->list);
+
+	rfcomm_session_clear_timer(s);
+	sock_release(s->sock);
+	kfree(s);
+
+	if (state != BT_LISTEN)
+		module_put(THIS_MODULE);
+
+	return NULL;
+}
+
+static struct rfcomm_session *rfcomm_session_get(bdaddr_t *src, bdaddr_t *dst)
+{
+	struct rfcomm_session *s, *n;
+	struct l2cap_chan *chan;
+	list_for_each_entry_safe(s, n, &session_list, list) {
+		chan = l2cap_pi(s->sock->sk)->chan;
+
+		if ((!bacmp(src, BDADDR_ANY) || !bacmp(&chan->src, src)) &&
+		    !bacmp(&chan->dst, dst))
+			return s;
+	}
+	return NULL;
+}
+
+static struct rfcomm_session *rfcomm_session_close(struct rfcomm_session *s,
+						   int err)
+{
+	struct rfcomm_dlc *d, *n;
+
+	s->state = BT_CLOSED;
+
+	BT_DBG("session %p state %ld err %d", s, s->state, err);
+
+	/* Close all dlcs */
+	list_for_each_entry_safe(d, n, &s->dlcs, list) {
+		d->state = BT_CLOSED;
+		__rfcomm_dlc_close(d, err);
+	}
+
+	rfcomm_session_clear_timer(s);
+	return rfcomm_session_del(s);
+}
+
+static struct rfcomm_session *rfcomm_session_create(bdaddr_t *src,
+							bdaddr_t *dst,
+							u8 sec_level,
+							int *err)
+{
+	struct rfcomm_session *s = NULL;
+	struct sockaddr_l2 addr;
+	struct socket *sock;
+	struct sock *sk;
+
+	BT_DBG("%pMR -> %pMR", src, dst);
+
+	*err = rfcomm_l2sock_create(&sock);
+	if (*err < 0)
+		return NULL;
+
+	bacpy(&addr.l2_bdaddr, src);
+	addr.l2_family = AF_BLUETOOTH;
+	addr.l2_psm    = 0;
+	addr.l2_cid    = 0;
+	addr.l2_bdaddr_type = BDADDR_BREDR;
+	*err = kernel_bind(sock, (struct sockaddr_unsized *)&addr, sizeof(addr));
+	if (*err < 0)
+		goto failed;
+
+	/* Set L2CAP options */
+	sk = sock->sk;
+	lock_sock(sk);
+	/* Set MTU to 0 so L2CAP can auto select the MTU */
+	l2cap_pi(sk)->chan->imtu = 0;
+	l2cap_pi(sk)->chan->sec_level = sec_level;
+	if (l2cap_ertm)
+		l2cap_pi(sk)->chan->mode = L2CAP_MODE_ERTM;
+	release_sock(sk);
+
+	s = rfcomm_session_add(sock, BT_BOUND);
+	if (!s) {
+		*err = -ENOMEM;
+		goto failed;
+	}
+
+	s->initiator = 1;
+
+	bacpy(&addr.l2_bdaddr, dst);
+	addr.l2_family = AF_BLUETOOTH;
+	addr.l2_psm    = cpu_to_le16(L2CAP_PSM_RFCOMM);
+	addr.l2_cid    = 0;
+	addr.l2_bdaddr_type = BDADDR_BREDR;
+	*err = kernel_connect(sock, (struct sockaddr_unsized *)&addr, sizeof(addr), O_NONBLOCK);
+	if (*err == 0 || *err == -EINPROGRESS)
+		return s;
+
+	return rfcomm_session_del(s);
+
+failed:
+	sock_release(sock);
+	return NULL;
+}
+
+void rfcomm_session_getaddr(struct rfcomm_session *s, bdaddr_t *src, bdaddr_t *dst)
+{
+	struct l2cap_chan *chan = l2cap_pi(s->sock->sk)->chan;
+	if (src)
+		bacpy(src, &chan->src);
+	if (dst)
+		bacpy(dst, &chan->dst);
+}
+
+/* ---- RFCOMM frame sending ---- */
+static int rfcomm_send_frame(struct rfcomm_session *s, u8 *data, int len)
+{
+	struct kvec iv = { data, len };
+	struct msghdr msg;
+
+	BT_DBG("session %p len %d", s, len);
+
+	memset(&msg, 0, sizeof(msg));
+
+	return kernel_sendmsg(s->sock, &msg, &iv, 1, len);
+}
+
+static int rfcomm_send_cmd(struct rfcomm_session *s, struct rfcomm_cmd *cmd)
+{
+	BT_DBG("%p cmd %u", s, cmd->ctrl);
+
+	return rfcomm_send_frame(s, (void *) cmd, sizeof(*cmd));
+}
+
+static int rfcomm_send_sabm(struct rfcomm_session *s, u8 dlci)
+{
+	struct rfcomm_cmd cmd;
+
+	BT_DBG("%p dlci %d", s, dlci);
+
+	cmd.addr = __addr(s->initiator, dlci);
+	cmd.ctrl = __ctrl(RFCOMM_SABM, 1);
+	cmd.len  = __len8(0);
+	cmd.fcs  = __fcs2((u8 *) &cmd);
+
+	return rfcomm_send_cmd(s, &cmd);
+}
+
+static int rfcomm_send_ua(struct rfcomm_session *s, u8 dlci)
+{
+	struct rfcomm_cmd cmd;
+
+	BT_DBG("%p dlci %d", s, dlci);
+
+	cmd.addr = __addr(!s->initiator, dlci);
+	cmd.ctrl = __ctrl(RFCOMM_UA, 1);
+	cmd.len  = __len8(0);
+	cmd.fcs  = __fcs2((u8 *) &cmd);
+
+	return rfcomm_send_cmd(s, &cmd);
+}
+
+static int rfcomm_send_disc(struct rfcomm_session *s, u8 dlci)
+{
+	struct rfcomm_cmd cmd;
+
+	BT_DBG("%p dlci %d", s, dlci);
+
+	cmd.addr = __addr(s->initiator, dlci);
+	cmd.ctrl = __ctrl(RFCOMM_DISC, 1);
+	cmd.len  = __len8(0);
+	cmd.fcs  = __fcs2((u8 *) &cmd);
+
+	return rfcomm_send_cmd(s, &cmd);
+}
+
+static int rfcomm_queue_disc(struct rfcomm_dlc *d)
+{
+	struct rfcomm_cmd *cmd;
+	struct sk_buff *skb;
+
+	BT_DBG("dlc %p dlci %d", d, d->dlci);
+
+	skb = alloc_skb(sizeof(*cmd), GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	cmd = __skb_put(skb, sizeof(*cmd));
+	cmd->addr = d->addr;
+	cmd->ctrl = __ctrl(RFCOMM_DISC, 1);
+	cmd->len  = __len8(0);
+	cmd->fcs  = __fcs2((u8 *) cmd);
+
+	skb_queue_tail(&d->tx_queue, skb);
+	rfcomm_schedule();
+	return 0;
+}
+
+static int rfcomm_send_dm(struct rfcomm_session *s, u8 dlci)
+{
+	struct rfcomm_cmd cmd;
+
+	BT_DBG("%p dlci %d", s, dlci);
+
+	cmd.addr = __addr(!s->initiator, dlci);
+	cmd.ctrl = __ctrl(RFCOMM_DM, 1);
+	cmd.len  = __len8(0);
+	cmd.fcs  = __fcs2((u8 *) &cmd);
+
+	return rfcomm_send_cmd(s, &cmd);
+}
+
+static int rfcomm_send_nsc(struct rfcomm_session *s, int cr, u8 type)
+{
+	struct rfcomm_hdr *hdr;
+	struct rfcomm_mcc *mcc;
+	u8 buf[16], *ptr = buf;
+
+	BT_DBG("%p cr %d type %d", s, cr, type);
+
+	hdr = (void *) ptr; ptr += sizeof(*hdr);
+	hdr->addr = __addr(s->initiator, 0);
+	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
+	hdr->len  = __len8(sizeof(*mcc) + 1);
+
+	mcc = (void *) ptr; ptr += sizeof(*mcc);
+	mcc->type = __mcc_type(0, RFCOMM_NSC);
+	mcc->len  = __len8(1);
+
+	/* Type that we didn't like */
+	*ptr = __mcc_type(cr, type); ptr++;
+
+	*ptr = __fcs(buf); ptr++;
+
+	return rfcomm_send_frame(s, buf, ptr - buf);
+}
+
+static int rfcomm_send_pn(struct rfcomm_session *s, int cr, struct rfcomm_dlc *d)
+{
+	struct rfcomm_hdr *hdr;
+	struct rfcomm_mcc *mcc;
+	struct rfcomm_pn  *pn;
+	u8 buf[16], *ptr = buf;
+
+	BT_DBG("%p cr %d dlci %d mtu %d", s, cr, d->dlci, d->mtu);
+
+	hdr = (void *) ptr; ptr += sizeof(*hdr);
+	hdr->addr = __addr(s->initiator, 0);
+	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
+	hdr->len  = __len8(sizeof(*mcc) + sizeof(*pn));
+
+	mcc = (void *) ptr; ptr += sizeof(*mcc);
+	mcc->type = __mcc_type(cr, RFCOMM_PN);
+	mcc->len  = __len8(sizeof(*pn));
+
+	pn = (void *) ptr; ptr += sizeof(*pn);
+	pn->dlci        = d->dlci;
+	pn->priority    = d->priority;
+	pn->ack_timer   = 0;
+	pn->max_retrans = 0;
+
+	if (s->cfc) {
+		pn->flow_ctrl = cr ? 0xf0 : 0xe0;
+		pn->credits = RFCOMM_DEFAULT_CREDITS;
+	} else {
+		pn->flow_ctrl = 0;
+		pn->credits   = 0;
+	}
+
+	if (cr && channel_mtu >= 0)
+		pn->mtu = cpu_to_le16(channel_mtu);
+	else
+		pn->mtu = cpu_to_le16(d->mtu);
+
+	*ptr = __fcs(buf); ptr++;
+
+	return rfcomm_send_frame(s, buf, ptr - buf);
+}
+
+int rfcomm_send_rpn(struct rfcomm_session *s, int cr, u8 dlci,
+			u8 bit_rate, u8 data_bits, u8 stop_bits,
+			u8 parity, u8 flow_ctrl_settings,
+			u8 xon_char, u8 xoff_char, u16 param_mask)
+{
+	struct rfcomm_hdr *hdr;
+	struct rfcomm_mcc *mcc;
+	struct rfcomm_rpn *rpn;
+	u8 buf[16], *ptr = buf;
+
+	BT_DBG("%p cr %d dlci %d bit_r 0x%x data_b 0x%x stop_b 0x%x parity 0x%x"
+			" flwc_s 0x%x xon_c 0x%x xoff_c 0x%x p_mask 0x%x",
+		s, cr, dlci, bit_rate, data_bits, stop_bits, parity,
+		flow_ctrl_settings, xon_char, xoff_char, param_mask);
+
+	hdr = (void *) ptr; ptr += sizeof(*hdr);
+	hdr->addr = __addr(s->initiator, 0);
+	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
+	hdr->len  = __len8(sizeof(*mcc) + sizeof(*rpn));
+
+	mcc = (void *) ptr; ptr += sizeof(*mcc);
+	mcc->type = __mcc_type(cr, RFCOMM_RPN);
+	mcc->len  = __len8(sizeof(*rpn));
+
+	rpn = (void *) ptr; ptr += sizeof(*rpn);
+	rpn->dlci          = __addr(1, dlci);
+	rpn->bit_rate      = bit_rate;
+	rpn->line_settings = __rpn_line_settings(data_bits, stop_bits, parity);
+	rpn->flow_ctrl     = flow_ctrl_settings;
+	rpn->xon_char      = xon_char;
+	rpn->xoff_char     = xoff_char;
+	rpn->param_mask    = cpu_to_le16(param_mask);
+
+	*ptr = __fcs(buf); ptr++;
+
+	return rfcomm_send_frame(s, buf, ptr - buf);
+}
+
+int rfcomm_dlc_send_rpn(struct rfcomm_dlc *d, u8 bit_rate, u8 data_bits,
+			u8 stop_bits, u8 parity, u8 flow_ctrl_settings,
+			u8 xon_char, u8 xoff_char, u16 param_mask)
+{
+	int err = -ENOTCONN;
+
+	rfcomm_lock();
+	if (d->session)
+		err = rfcomm_send_rpn(d->session, 1, d->dlci, bit_rate,
+				      data_bits, stop_bits, parity,
+				      flow_ctrl_settings, xon_char, xoff_char,
+				      param_mask);
+	rfcomm_unlock();
+
+	return err;
+}
+
+static int rfcomm_send_rls(struct rfcomm_session *s, int cr, u8 dlci, u8 status)
+{
+	struct rfcomm_hdr *hdr;
+	struct rfcomm_mcc *mcc;
+	struct rfcomm_rls *rls;
+	u8 buf[16], *ptr = buf;
+
+	BT_DBG("%p cr %d status 0x%x", s, cr, status);
+
+	hdr = (void *) ptr; ptr += sizeof(*hdr);
+	hdr->addr = __addr(s->initiator, 0);
+	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
+	hdr->len  = __len8(sizeof(*mcc) + sizeof(*rls));
+
+	mcc = (void *) ptr; ptr += sizeof(*mcc);
+	mcc->type = __mcc_type(cr, RFCOMM_RLS);
+	mcc->len  = __len8(sizeof(*rls));
+
+	rls = (void *) ptr; ptr += sizeof(*rls);
+	rls->dlci   = __addr(1, dlci);
+	rls->status = status;
+
+	*ptr = __fcs(buf); ptr++;
+
+	return rfcomm_send_frame(s, buf, ptr - buf);
+}
+
+static int rfcomm_send_msc(struct rfcomm_session *s, int cr, u8 dlci, u8 v24_sig)
+{
+	struct rfcomm_hdr *hdr;
+	struct rfcomm_mcc *mcc;
+	struct rfcomm_msc *msc;
+	u8 buf[16], *ptr = buf;
+
+	BT_DBG("%p cr %d v24 0x%x", s, cr, v24_sig);
+
+	hdr = (void *) ptr; ptr += sizeof(*hdr);
+	hdr->addr = __addr(s->initiator, 0);
+	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
+	hdr->len  = __len8(sizeof(*mcc) + sizeof(*msc));
+
+	mcc = (void *) ptr; ptr += sizeof(*mcc);
+	mcc->type = __mcc_type(cr, RFCOMM_MSC);
+	mcc->len  = __len8(sizeof(*msc));
+
+	msc = (void *) ptr; ptr += sizeof(*msc);
+	msc->dlci    = __addr(1, dlci);
+	msc->v24_sig = v24_sig | 0x01;
+
+	*ptr = __fcs(buf); ptr++;
+
+	return rfcomm_send_frame(s, buf, ptr - buf);
+}
+
+static int rfcomm_send_fcoff(struct rfcomm_session *s, int cr)
+{
+	struct rfcomm_hdr *hdr;
+	struct rfcomm_mcc *mcc;
+	u8 buf[16], *ptr = buf;
+
+	BT_DBG("%p cr %d", s, cr);
+
+	hdr = (void *) ptr; ptr += sizeof(*hdr);
+	hdr->addr = __addr(s->initiator, 0);
+	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
+	hdr->len  = __len8(sizeof(*mcc));
+
+	mcc = (void *) ptr; ptr += sizeof(*mcc);
+	mcc->type = __mcc_type(cr, RFCOMM_FCOFF);
+	mcc->len  = __len8(0);
+
+	*ptr = __fcs(buf); ptr++;
+
+	return rfcomm_send_frame(s, buf, ptr - buf);
+}
+
+static int rfcomm_send_fcon(struct rfcomm_session *s, int cr)
+{
+	struct rfcomm_hdr *hdr;
+	struct rfcomm_mcc *mcc;
+	u8 buf[16], *ptr = buf;
+
+	BT_DBG("%p cr %d", s, cr);
+
+	hdr = (void *) ptr; ptr += sizeof(*hdr);
+	hdr->addr = __addr(s->initiator, 0);
+	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
+	hdr->len  = __len8(sizeof(*mcc));
+
+	mcc = (void *) ptr; ptr += sizeof(*mcc);
+	mcc->type = __mcc_type(cr, RFCOMM_FCON);
+	mcc->len  = __len8(0);
+
+	*ptr = __fcs(buf); ptr++;
+
+	return rfcomm_send_frame(s, buf, ptr - buf);
+}
+
+static int rfcomm_send_test(struct rfcomm_session *s, int cr, u8 *pattern, int len)
+{
+	struct socket *sock = s->sock;
+	struct kvec iv[3];
+	struct msghdr msg;
+	unsigned char hdr[5], crc[1];
+
+	if (len > 125)
+		return -EINVAL;
+
+	BT_DBG("%p cr %d", s, cr);
+
+	hdr[0] = __addr(s->initiator, 0);
+	hdr[1] = __ctrl(RFCOMM_UIH, 0);
+	hdr[2] = 0x01 | ((len + 2) << 1);
+	hdr[3] = 0x01 | ((cr & 0x01) << 1) | (RFCOMM_TEST << 2);
+	hdr[4] = 0x01 | (len << 1);
+
+	crc[0] = __fcs(hdr);
+
+	iv[0].iov_base = hdr;
+	iv[0].iov_len  = 5;
+	iv[1].iov_base = pattern;
+	iv[1].iov_len  = len;
+	iv[2].iov_base = crc;
+	iv[2].iov_len  = 1;
+
+	memset(&msg, 0, sizeof(msg));
+
+	return kernel_sendmsg(sock, &msg, iv, 3, 6 + len);
+}
+
+static int rfcomm_send_credits(struct rfcomm_session *s, u8 addr, u8 credits)
+{
+	struct rfcomm_hdr *hdr;
+	u8 buf[16], *ptr = buf;
+
+	BT_DBG("%p addr %d credits %d", s, addr, credits);
+
+	hdr = (void *) ptr; ptr += sizeof(*hdr);
+	hdr->addr = addr;
+	hdr->ctrl = __ctrl(RFCOMM_UIH, 1);
+	hdr->len  = __len8(0);
+
+	*ptr = credits; ptr++;
+
+	*ptr = __fcs(buf); ptr++;
+
+	return rfcomm_send_frame(s, buf, ptr - buf);
+}
+
+static void rfcomm_make_uih(struct sk_buff *skb, u8 addr)
+{
+	struct rfcomm_hdr *hdr;
+	int len = skb->len;
+	u8 *crc;
+
+	if (len > 127) {
+		hdr = skb_push(skb, 4);
+		put_unaligned(cpu_to_le16(__len16(len)), (__le16 *) &hdr->len);
+	} else {
+		hdr = skb_push(skb, 3);
+		hdr->len = __len8(len);
+	}
+	hdr->addr = addr;
+	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
+
+	crc = skb_put(skb, 1);
+	*crc = __fcs((void *) hdr);
+}
+
+/* ---- RFCOMM frame reception ---- */
+static struct rfcomm_session *rfcomm_recv_ua(struct rfcomm_session *s, u8 dlci)
+{
+	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
+
+	if (dlci) {
+		/* Data channel */
+		struct rfcomm_dlc *d = rfcomm_dlc_get(s, dlci);
+		if (!d) {
+			rfcomm_send_dm(s, dlci);
+			return s;
+		}
+
+		switch (d->state) {
+		case BT_CONNECT:
+			rfcomm_dlc_clear_timer(d);
+
+			rfcomm_dlc_lock(d);
+			d->state = BT_CONNECTED;
+			d->state_change(d, 0);
+			rfcomm_dlc_unlock(d);
+
+			rfcomm_send_msc(s, 1, dlci, d->v24_sig);
+			break;
+
+		case BT_DISCONN:
+			d->state = BT_CLOSED;
+			__rfcomm_dlc_close(d, 0);
+
+			if (list_empty(&s->dlcs)) {
+				s->state = BT_DISCONN;
+				rfcomm_send_disc(s, 0);
+				rfcomm_session_clear_timer(s);
+			}
+
+			break;
+		}
+	} else {
+		/* Control channel */
+		switch (s->state) {
+		case BT_CONNECT:
+			s->state = BT_CONNECTED;
+			rfcomm_process_connect(s);
+			break;
+
+		case BT_DISCONN:
+			s = rfcomm_session_close(s, ECONNRESET);
+			break;
+		}
+	}
+	return s;
+}
+
+static struct rfcomm_session *rfcomm_recv_dm(struct rfcomm_session *s, u8 dlci)
+{
+	int err = 0;
+
+	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
+
+	if (dlci) {
+		/* Data DLC */
+		struct rfcomm_dlc *d = rfcomm_dlc_get(s, dlci);
+		if (d) {
+			if (d->state == BT_CONNECT || d->state == BT_CONFIG)
+				err = ECONNREFUSED;
+			else
+				err = ECONNRESET;
+
+			d->state = BT_CLOSED;
+			__rfcomm_dlc_close(d, err);
+		}
+	} else {
+		if (s->state == BT_CONNECT)
+			err = ECONNREFUSED;
+		else
+			err = ECONNRESET;
+
+		s = rfcomm_session_close(s, err);
+	}
+	return s;
+}
+
+static struct rfcomm_session *rfcomm_recv_disc(struct rfcomm_session *s,
+					       u8 dlci)
+{
+	int err = 0;
+
+	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
+
+	if (dlci) {
+		struct rfcomm_dlc *d = rfcomm_dlc_get(s, dlci);
+		if (d) {
+			rfcomm_send_ua(s, dlci);
+
+			if (d->state == BT_CONNECT || d->state == BT_CONFIG)
+				err = ECONNREFUSED;
+			else
+				err = ECONNRESET;
+
+			d->state = BT_CLOSED;
+			__rfcomm_dlc_close(d, err);
+		} else
+			rfcomm_send_dm(s, dlci);
+
+	} else {
+		rfcomm_send_ua(s, 0);
+
+		if (s->state == BT_CONNECT)
+			err = ECONNREFUSED;
+		else
+			err = ECONNRESET;
+
+		s = rfcomm_session_close(s, err);
+	}
+	return s;
+}
+
+/* Must be called with rfcomm_mutex held, so that the session cannot be
+ * unlinked from under us.
+ */
+static void __rfcomm_dlc_accept(struct rfcomm_dlc *d)
+{
+	struct sock *sk = d->session->sock->sk;
+	struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
+
+	BT_DBG("dlc %p", d);
+
+	rfcomm_send_ua(d->session, d->dlci);
+
+	rfcomm_dlc_clear_timer(d);
+
+	rfcomm_dlc_lock(d);
+	d->state = BT_CONNECTED;
+	d->state_change(d, 0);
+	rfcomm_dlc_unlock(d);
+
+	if (d->role_switch)
+		hci_conn_switch_role(conn->hcon, 0x00);
+
+	rfcomm_send_msc(d->session, 1, d->dlci, d->v24_sig);
+}
+
+void rfcomm_dlc_accept(struct rfcomm_dlc *d)
+{
+	rfcomm_lock();
+
+	/* rfcomm_recv_disc() sets the dlc state to BT_CLOSED before calling
+	 * __rfcomm_dlc_close(), so the RFCOMM_DEFER_SETUP handshake there is
+	 * skipped and the session can already be unlinked by the time the
+	 * deferred accept runs from rfcomm_sock_recvmsg().
+	 */
+	if (d->session)
+		__rfcomm_dlc_accept(d);
+
+	rfcomm_unlock();
+}
+
+static void rfcomm_check_accept(struct rfcomm_dlc *d)
+{
+	if (rfcomm_check_security(d)) {
+		if (d->defer_setup) {
+			set_bit(RFCOMM_DEFER_SETUP, &d->flags);
+			rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
+
+			rfcomm_dlc_lock(d);
+			d->state = BT_CONNECT2;
+			d->state_change(d, 0);
+			rfcomm_dlc_unlock(d);
+		} else
+			__rfcomm_dlc_accept(d);
+	} else {
+		set_bit(RFCOMM_AUTH_PENDING, &d->flags);
+		rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
+	}
+}
+
+static int rfcomm_recv_sabm(struct rfcomm_session *s, u8 dlci)
+{
+	struct rfcomm_dlc *d;
+	u8 channel;
+
+	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
+
+	if (!dlci) {
+		rfcomm_send_ua(s, 0);
+
+		if (s->state == BT_OPEN) {
+			s->state = BT_CONNECTED;
+			rfcomm_process_connect(s);
+		}
+		return 0;
+	}
+
+	/* Check if DLC exists */
+	d = rfcomm_dlc_get(s, dlci);
+	if (d) {
+		if (d->state == BT_OPEN) {
+			/* DLC was previously opened by PN request */
+			rfcomm_check_accept(d);
+		}
+		return 0;
+	}
+
+	/* Notify socket layer about incoming connection */
+	channel = __srv_channel(dlci);
+	if (rfcomm_connect_ind(s, channel, &d)) {
+		d->dlci = dlci;
+		d->addr = __addr(s->initiator, dlci);
+		rfcomm_dlc_link(s, d);
+
+		rfcomm_check_accept(d);
+	} else {
+		rfcomm_send_dm(s, dlci);
+	}
+
+	return 0;
+}
+
+static int rfcomm_apply_pn(struct rfcomm_dlc *d, int cr, struct rfcomm_pn *pn)
+{
+	struct rfcomm_session *s = d->session;
+
+	BT_DBG("dlc %p state %ld dlci %d mtu %d fc 0x%x credits %d",
+			d, d->state, d->dlci, pn->mtu, pn->flow_ctrl, pn->credits);
+
+	if ((pn->flow_ctrl == 0xf0 && s->cfc != RFCOMM_CFC_DISABLED) ||
+						pn->flow_ctrl == 0xe0) {
+		d->cfc = RFCOMM_CFC_ENABLED;
+		d->tx_credits = pn->credits;
+	} else {
+		d->cfc = RFCOMM_CFC_DISABLED;
+		set_bit(RFCOMM_TX_THROTTLED, &d->flags);
+	}
+
+	if (s->cfc == RFCOMM_CFC_UNKNOWN)
+		s->cfc = d->cfc;
+
+	d->priority = pn->priority;
+
+	d->mtu = __le16_to_cpu(pn->mtu);
+
+	/* MTU 0 causes an infinite loop when fragmenting in sendmsg */
+	if (!d->mtu)
+		d->mtu = RFCOMM_DEFAULT_MTU;
+
+	if (cr && d->mtu > s->mtu)
+		d->mtu = s->mtu;
+
+	return 0;
+}
+
+static int rfcomm_recv_pn(struct rfcomm_session *s, int cr, struct sk_buff *skb)
+{
+	struct rfcomm_pn *pn;
+	struct rfcomm_dlc *d;
+	u8 dlci;
+
+	pn = skb_pull_data(skb, sizeof(*pn));
+	if (!pn)
+		return -EILSEQ;
+
+	dlci = pn->dlci;
+	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
+
+	if (!dlci)
+		return 0;
+
+	d = rfcomm_dlc_get(s, dlci);
+	if (d) {
+		if (cr) {
+			/* PN request */
+			rfcomm_apply_pn(d, cr, pn);
+			rfcomm_send_pn(s, 0, d);
+		} else {
+			/* PN response */
+			switch (d->state) {
+			case BT_CONFIG:
+				rfcomm_apply_pn(d, cr, pn);
+
+				d->state = BT_CONNECT;
+				rfcomm_send_sabm(s, d->dlci);
+				break;
+			}
+		}
+	} else {
+		u8 channel = __srv_channel(dlci);
+
+		if (!cr)
+			return 0;
+
+		/* PN request for non existing DLC.
+		 * Assume incoming connection. */
+		if (rfcomm_connect_ind(s, channel, &d)) {
+			d->dlci = dlci;
+			d->addr = __addr(s->initiator, dlci);
+			rfcomm_dlc_link(s, d);
+
+			rfcomm_apply_pn(d, cr, pn);
+
+			d->state = BT_OPEN;
+			rfcomm_send_pn(s, 0, d);
+		} else {
+			rfcomm_send_dm(s, dlci);
+		}
+	}
+	return 0;
+}
+
+static int rfcomm_recv_rpn(struct rfcomm_session *s, int cr, int len, struct sk_buff *skb)
+{
+	struct rfcomm_rpn *rpn;
+	u8 dlci;
+
+	u8 bit_rate  = 0;
+	u8 data_bits = 0;
+	u8 stop_bits = 0;
+	u8 parity    = 0;
+	u8 flow_ctrl = 0;
+	u8 xon_char  = 0;
+	u8 xoff_char = 0;
+	u16 rpn_mask = RFCOMM_RPN_PM_ALL;
+
+	if (len == 1) {
+		rpn = skb_pull_data(skb, 1);
+		if (!rpn)
+			return -EILSEQ;
+
+		dlci = __get_dlci(rpn->dlci);
+
+		if (!cr)
+			return 0;
+
+		bit_rate  = RFCOMM_RPN_BR_9600;
+		data_bits = RFCOMM_RPN_DATA_8;
+		stop_bits = RFCOMM_RPN_STOP_1;
+		parity    = RFCOMM_RPN_PARITY_NONE;
+		flow_ctrl = RFCOMM_RPN_FLOW_NONE;
+		xon_char  = RFCOMM_RPN_XON_CHAR;
+		xoff_char = RFCOMM_RPN_XOFF_CHAR;
+		goto rpn_out;
+	}
+
+	rpn = skb_pull_data(skb, sizeof(*rpn));
+	if (!rpn)
+		return -EILSEQ;
+
+	dlci = __get_dlci(rpn->dlci);
+
+	BT_DBG("dlci %d cr %d len 0x%x bitr 0x%x line 0x%x flow 0x%x xonc 0x%x xoffc 0x%x pm 0x%x",
+	       dlci, cr, len, rpn->bit_rate, rpn->line_settings, rpn->flow_ctrl,
+	       rpn->xon_char, rpn->xoff_char, rpn->param_mask);
+
+	if (!cr)
+		return 0;
+
+	/* Check for sane values, ignore/accept bit_rate, 8 bits, 1 stop bit,
+	 * no parity, no flow control lines, normal XON/XOFF chars */
+
+	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_BITRATE)) {
+		bit_rate = rpn->bit_rate;
+		if (bit_rate > RFCOMM_RPN_BR_230400) {
+			BT_DBG("RPN bit rate mismatch 0x%x", bit_rate);
+			bit_rate = RFCOMM_RPN_BR_9600;
+			rpn_mask ^= RFCOMM_RPN_PM_BITRATE;
+		}
+	}
+
+	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_DATA)) {
+		data_bits = __get_rpn_data_bits(rpn->line_settings);
+		if (data_bits != RFCOMM_RPN_DATA_8) {
+			BT_DBG("RPN data bits mismatch 0x%x", data_bits);
+			data_bits = RFCOMM_RPN_DATA_8;
+			rpn_mask ^= RFCOMM_RPN_PM_DATA;
+		}
+	}
+
+	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_STOP)) {
+		stop_bits = __get_rpn_stop_bits(rpn->line_settings);
+		if (stop_bits != RFCOMM_RPN_STOP_1) {
+			BT_DBG("RPN stop bits mismatch 0x%x", stop_bits);
+			stop_bits = RFCOMM_RPN_STOP_1;
+			rpn_mask ^= RFCOMM_RPN_PM_STOP;
+		}
+	}
+
+	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_PARITY)) {
+		parity = __get_rpn_parity(rpn->line_settings);
+		if (parity != RFCOMM_RPN_PARITY_NONE) {
+			BT_DBG("RPN parity mismatch 0x%x", parity);
+			parity = RFCOMM_RPN_PARITY_NONE;
+			rpn_mask ^= RFCOMM_RPN_PM_PARITY;
+		}
+	}
+
+	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_FLOW)) {
+		flow_ctrl = rpn->flow_ctrl;
+		if (flow_ctrl != RFCOMM_RPN_FLOW_NONE) {
+			BT_DBG("RPN flow ctrl mismatch 0x%x", flow_ctrl);
+			flow_ctrl = RFCOMM_RPN_FLOW_NONE;
+			rpn_mask ^= RFCOMM_RPN_PM_FLOW;
+		}
+	}
+
+	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_XON)) {
+		xon_char = rpn->xon_char;
+		if (xon_char != RFCOMM_RPN_XON_CHAR) {
+			BT_DBG("RPN XON char mismatch 0x%x", xon_char);
+			xon_char = RFCOMM_RPN_XON_CHAR;
+			rpn_mask ^= RFCOMM_RPN_PM_XON;
+		}
+	}
+
+	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_XOFF)) {
+		xoff_char = rpn->xoff_char;
+		if (xoff_char != RFCOMM_RPN_XOFF_CHAR) {
+			BT_DBG("RPN XOFF char mismatch 0x%x", xoff_char);
+			xoff_char = RFCOMM_RPN_XOFF_CHAR;
+			rpn_mask ^= RFCOMM_RPN_PM_XOFF;
+		}
+	}
+
+rpn_out:
+	rfcomm_send_rpn(s, 0, dlci, bit_rate, data_bits, stop_bits,
+			parity, flow_ctrl, xon_char, xoff_char, rpn_mask);
+
+	return 0;
+}
+
+static int rfcomm_recv_rls(struct rfcomm_session *s, int cr, struct sk_buff *skb)
+{
+	struct rfcomm_rls *rls;
+	u8 dlci;
+
+	rls = skb_pull_data(skb, sizeof(*rls));
+	if (!rls)
+		return -EILSEQ;
+
+	dlci = __get_dlci(rls->dlci);
+	BT_DBG("dlci %d cr %d status 0x%x", dlci, cr, rls->status);
+
+	if (!cr)
+		return 0;
+
+	/* We should probably do something with this information here. But
+	 * for now it's sufficient just to reply -- Bluetooth 1.1 says it's
+	 * mandatory to recognise and respond to RLS */
+
+	rfcomm_send_rls(s, 0, dlci, rls->status);
+
+	return 0;
+}
+
+static int rfcomm_recv_msc(struct rfcomm_session *s, int cr, struct sk_buff *skb)
+{
+	struct rfcomm_msc *msc;
+	struct rfcomm_dlc *d;
+	u8 dlci;
+
+	msc = skb_pull_data(skb, sizeof(*msc));
+	if (!msc)
+		return -EILSEQ;
+
+	dlci = __get_dlci(msc->dlci);
+	BT_DBG("dlci %d cr %d v24 0x%x", dlci, cr, msc->v24_sig);
+
+	d = rfcomm_dlc_get(s, dlci);
+	if (!d)
+		return 0;
+
+	if (cr) {
+		if (msc->v24_sig & RFCOMM_V24_FC && !d->cfc)
+			set_bit(RFCOMM_TX_THROTTLED, &d->flags);
+		else
+			clear_bit(RFCOMM_TX_THROTTLED, &d->flags);
+
+		rfcomm_dlc_lock(d);
+
+		d->remote_v24_sig = msc->v24_sig;
+
+		if (d->modem_status)
+			d->modem_status(d, msc->v24_sig);
+
+		rfcomm_dlc_unlock(d);
+
+		rfcomm_send_msc(s, 0, dlci, msc->v24_sig);
+
+		d->mscex |= RFCOMM_MSCEX_RX;
+	} else
+		d->mscex |= RFCOMM_MSCEX_TX;
+
+	return 0;
+}
+
+static int rfcomm_recv_mcc(struct rfcomm_session *s, struct sk_buff *skb)
+{
+	struct rfcomm_mcc *mcc;
+	u8 type, cr, len;
+
+	mcc = skb_pull_data(skb, sizeof(*mcc));
+	if (!mcc)
+		return -EILSEQ;
+
+	cr   = __test_cr(mcc->type);
+	type = __get_mcc_type(mcc->type);
+	len  = __get_mcc_len(mcc->len);
+
+	BT_DBG("%p type 0x%x cr %d", s, type, cr);
+
+	switch (type) {
+	case RFCOMM_PN:
+		rfcomm_recv_pn(s, cr, skb);
+		break;
+
+	case RFCOMM_RPN:
+		rfcomm_recv_rpn(s, cr, len, skb);
+		break;
+
+	case RFCOMM_RLS:
+		rfcomm_recv_rls(s, cr, skb);
+		break;
+
+	case RFCOMM_MSC:
+		rfcomm_recv_msc(s, cr, skb);
+		break;
+
+	case RFCOMM_FCOFF:
+		if (cr) {
+			set_bit(RFCOMM_TX_THROTTLED, &s->flags);
+			rfcomm_send_fcoff(s, 0);
+		}
+		break;
+
+	case RFCOMM_FCON:
+		if (cr) {
+			clear_bit(RFCOMM_TX_THROTTLED, &s->flags);
+			rfcomm_send_fcon(s, 0);
+		}
+		break;
+
+	case RFCOMM_TEST:
+		if (cr)
+			rfcomm_send_test(s, 0, skb->data, skb->len);
+		break;
+
+	case RFCOMM_NSC:
+		break;
+
+	default:
+		BT_ERR("Unknown control type 0x%02x", type);
+		rfcomm_send_nsc(s, cr, type);
+		break;
+	}
+	return 0;
+}
+
+static int rfcomm_recv_data(struct rfcomm_session *s, u8 dlci, int pf, struct sk_buff *skb)
+{
+	struct rfcomm_dlc *d;
+
+	BT_DBG("session %p state %ld dlci %d pf %d", s, s->state, dlci, pf);
+
+	d = rfcomm_dlc_get(s, dlci);
+	if (!d) {
+		rfcomm_send_dm(s, dlci);
+		goto drop;
+	}
+
+	if (pf && d->cfc) {
+		u8 *credits = skb_pull_data(skb, 1);
+
+		if (!credits)
+			goto drop;
+
+		d->tx_credits += *credits;
+		if (d->tx_credits)
+			clear_bit(RFCOMM_TX_THROTTLED, &d->flags);
+	}
+
+	if (skb->len && d->state == BT_CONNECTED) {
+		rfcomm_dlc_lock(d);
+		d->rx_credits--;
+		d->data_ready(d, skb);
+		rfcomm_dlc_unlock(d);
+		return 0;
+	}
+
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+
+static struct rfcomm_session *rfcomm_recv_frame(struct rfcomm_session *s,
+						struct sk_buff *skb)
+{
+	struct rfcomm_hdr *hdr = (void *) skb->data;
+	u8 type, dlci, fcs;
+
+	if (!s) {
+		/* no session, so free socket data */
+		kfree_skb(skb);
+		return s;
+	}
+
+	if (skb->len < sizeof(*hdr) + 1) {
+		kfree_skb(skb);
+		return s;
+	}
+
+	dlci = __get_dlci(hdr->addr);
+	type = __get_type(hdr->ctrl);
+
+	/* Trim FCS */
+	skb->len--; skb->tail--;
+	fcs = *(u8 *)skb_tail_pointer(skb);
+
+	if (__check_fcs(skb->data, type, fcs)) {
+		BT_ERR("bad checksum in packet");
+		kfree_skb(skb);
+		return s;
+	}
+
+	if (__test_ea(hdr->len))
+		skb_pull(skb, 3);
+	else
+		skb_pull(skb, 4);
+
+	switch (type) {
+	case RFCOMM_SABM:
+		if (__test_pf(hdr->ctrl))
+			rfcomm_recv_sabm(s, dlci);
+		break;
+
+	case RFCOMM_DISC:
+		if (__test_pf(hdr->ctrl))
+			s = rfcomm_recv_disc(s, dlci);
+		break;
+
+	case RFCOMM_UA:
+		if (__test_pf(hdr->ctrl))
+			s = rfcomm_recv_ua(s, dlci);
+		break;
+
+	case RFCOMM_DM:
+		s = rfcomm_recv_dm(s, dlci);
+		break;
+
+	case RFCOMM_UIH:
+		if (dlci) {
+			rfcomm_recv_data(s, dlci, __test_pf(hdr->ctrl), skb);
+			return s;
+		}
+		rfcomm_recv_mcc(s, skb);
+		break;
+
+	default:
+		BT_ERR("Unknown packet type 0x%02x", type);
+		break;
+	}
+	kfree_skb(skb);
+	return s;
+}
+
+/* ---- Connection and data processing ---- */
+
+static void rfcomm_process_connect(struct rfcomm_session *s)
+{
+	struct rfcomm_dlc *d, *n;
+
+	BT_DBG("session %p state %ld", s, s->state);
+
+	list_for_each_entry_safe(d, n, &s->dlcs, list) {
+		if (d->state == BT_CONFIG) {
+			d->mtu = s->mtu;
+			if (rfcomm_check_security(d)) {
+				rfcomm_send_pn(s, 1, d);
+			} else {
+				set_bit(RFCOMM_AUTH_PENDING, &d->flags);
+				rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
+			}
+		}
+	}
+}
+
+/* Send data queued for the DLC.
+ * Return number of frames left in the queue.
+ */
+static int rfcomm_process_tx(struct rfcomm_dlc *d)
+{
+	struct sk_buff *skb;
+	int err;
+
+	BT_DBG("dlc %p state %ld cfc %d rx_credits %d tx_credits %d",
+			d, d->state, d->cfc, d->rx_credits, d->tx_credits);
+
+	/* Send pending MSC */
+	if (test_and_clear_bit(RFCOMM_MSC_PENDING, &d->flags))
+		rfcomm_send_msc(d->session, 1, d->dlci, d->v24_sig);
+
+	if (d->cfc) {
+		/* CFC enabled.
+		 * Give them some credits */
+		if (!test_bit(RFCOMM_RX_THROTTLED, &d->flags) &&
+				d->rx_credits <= (d->cfc >> 2)) {
+			rfcomm_send_credits(d->session, d->addr, d->cfc - d->rx_credits);
+			d->rx_credits = d->cfc;
+		}
+	} else {
+		/* CFC disabled.
+		 * Give ourselves some credits */
+		d->tx_credits = 5;
+	}
+
+	if (test_bit(RFCOMM_TX_THROTTLED, &d->flags))
+		return skb_queue_len(&d->tx_queue);
+
+	while (d->tx_credits && (skb = skb_dequeue(&d->tx_queue))) {
+		err = rfcomm_send_frame(d->session, skb->data, skb->len);
+		if (err < 0) {
+			skb_queue_head(&d->tx_queue, skb);
+			break;
+		}
+		kfree_skb(skb);
+		d->tx_credits--;
+	}
+
+	if (d->cfc && !d->tx_credits) {
+		/* We're out of TX credits.
+		 * Set TX_THROTTLED flag to avoid unnesary wakeups by dlc_send. */
+		set_bit(RFCOMM_TX_THROTTLED, &d->flags);
+	}
+
+	return skb_queue_len(&d->tx_queue);
+}
+
+static void rfcomm_process_dlcs(struct rfcomm_session *s)
+{
+	struct rfcomm_dlc *d, *n;
+
+	BT_DBG("session %p state %ld", s, s->state);
+
+	list_for_each_entry_safe(d, n, &s->dlcs, list) {
+		if (test_bit(RFCOMM_TIMED_OUT, &d->flags)) {
+			__rfcomm_dlc_close(d, ETIMEDOUT);
+			continue;
+		}
+
+		if (test_bit(RFCOMM_ENC_DROP, &d->flags)) {
+			__rfcomm_dlc_close(d, ECONNREFUSED);
+			continue;
+		}
+
+		if (test_and_clear_bit(RFCOMM_AUTH_ACCEPT, &d->flags)) {
+			rfcomm_dlc_clear_timer(d);
+			if (d->out) {
+				rfcomm_send_pn(s, 1, d);
+				rfcomm_dlc_set_timer(d, RFCOMM_CONN_TIMEOUT);
+			} else {
+				if (d->defer_setup) {
+					set_bit(RFCOMM_DEFER_SETUP, &d->flags);
+					rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
+
+					rfcomm_dlc_lock(d);
+					d->state = BT_CONNECT2;
+					d->state_change(d, 0);
+					rfcomm_dlc_unlock(d);
+				} else
+					__rfcomm_dlc_accept(d);
+			}
+			continue;
+		} else if (test_and_clear_bit(RFCOMM_AUTH_REJECT, &d->flags)) {
+			rfcomm_dlc_clear_timer(d);
+			if (!d->out)
+				rfcomm_send_dm(s, d->dlci);
+			else
+				d->state = BT_CLOSED;
+			__rfcomm_dlc_close(d, ECONNREFUSED);
+			continue;
+		}
+
+		if (test_bit(RFCOMM_SEC_PENDING, &d->flags))
+			continue;
+
+		if (test_bit(RFCOMM_TX_THROTTLED, &s->flags))
+			continue;
+
+		if ((d->state == BT_CONNECTED || d->state == BT_DISCONN) &&
+						d->mscex == RFCOMM_MSCEX_OK)
+			rfcomm_process_tx(d);
+	}
+}
+
+static struct rfcomm_session *rfcomm_process_rx(struct rfcomm_session *s)
+{
+	struct socket *sock = s->sock;
+	struct sock *sk = sock->sk;
+	struct sk_buff *skb;
+
+	BT_DBG("session %p state %ld qlen %d", s, s->state, skb_queue_len(&sk->sk_receive_queue));
+
+	/* Get data directly from socket receive queue without copying it. */
+	while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
+		skb_orphan(skb);
+		if (!skb_linearize(skb) && sk->sk_state != BT_CLOSED) {
+			s = rfcomm_recv_frame(s, skb);
+			if (!s)
+				break;
+		} else {
+			kfree_skb(skb);
+		}
+	}
+
+	if (s && (sk->sk_state == BT_CLOSED))
+		s = rfcomm_session_close(s, sk->sk_err);
+
+	return s;
+}
+
+static void rfcomm_accept_connection(struct rfcomm_session *s)
+{
+	struct socket *sock = s->sock, *nsock;
+	int err;
+
+	/* Fast check for a new connection.
+	 * Avoids unnecessary socket allocations.
+	 */
+	if (list_empty(&bt_sk(sock->sk)->accept_q))
+		return;
+
+	BT_DBG("session %p", s);
+
+	err = kernel_accept(sock, &nsock, O_NONBLOCK);
+	if (err < 0)
+		return;
+
+	/* Set our callbacks */
+	nsock->sk->sk_data_ready   = rfcomm_l2data_ready;
+	nsock->sk->sk_state_change = rfcomm_l2state_change;
+
+	s = rfcomm_session_add(nsock, BT_OPEN);
+	if (s) {
+		/* We should adjust MTU on incoming sessions.
+		 * L2CAP MTU minus UIH header and FCS. */
+		s->mtu = min(l2cap_pi(nsock->sk)->chan->omtu,
+				l2cap_pi(nsock->sk)->chan->imtu) - 5;
+
+		rfcomm_schedule();
+	} else
+		sock_release(nsock);
+}
+
+static struct rfcomm_session *rfcomm_check_connection(struct rfcomm_session *s)
+{
+	struct sock *sk = s->sock->sk;
+
+	BT_DBG("%p state %ld", s, s->state);
+
+	switch (sk->sk_state) {
+	case BT_CONNECTED:
+		s->state = BT_CONNECT;
+
+		/* We can adjust MTU on outgoing sessions.
+		 * L2CAP MTU minus UIH header and FCS. */
+		s->mtu = min(l2cap_pi(sk)->chan->omtu, l2cap_pi(sk)->chan->imtu) - 5;
+
+		rfcomm_send_sabm(s, 0);
+		break;
+
+	case BT_CLOSED:
+		s = rfcomm_session_close(s, sk->sk_err);
+		break;
+	}
+	return s;
+}
+
+static void rfcomm_process_sessions(void)
+{
+	struct rfcomm_session *s, *n;
+
+	rfcomm_lock();
+
+	list_for_each_entry_safe(s, n, &session_list, list) {
+		if (test_and_clear_bit(RFCOMM_TIMED_OUT, &s->flags)) {
+			s->state = BT_DISCONN;
+			rfcomm_send_disc(s, 0);
+			continue;
+		}
+
+		switch (s->state) {
+		case BT_LISTEN:
+			rfcomm_accept_connection(s);
+			continue;
+
+		case BT_BOUND:
+			s = rfcomm_check_connection(s);
+			break;
+
+		default:
+			s = rfcomm_process_rx(s);
+			break;
+		}
+
+		if (s)
+			rfcomm_process_dlcs(s);
+	}
+
+	rfcomm_unlock();
+}
+
+static int rfcomm_add_listener(bdaddr_t *ba)
+{
+	struct sockaddr_l2 addr;
+	struct socket *sock;
+	struct sock *sk;
+	struct rfcomm_session *s;
+	int    err = 0;
+
+	/* Create socket */
+	err = rfcomm_l2sock_create(&sock);
+	if (err < 0) {
+		BT_ERR("Create socket failed %d", err);
+		return err;
+	}
+
+	/* Bind socket */
+	bacpy(&addr.l2_bdaddr, ba);
+	addr.l2_family = AF_BLUETOOTH;
+	addr.l2_psm    = cpu_to_le16(L2CAP_PSM_RFCOMM);
+	addr.l2_cid    = 0;
+	addr.l2_bdaddr_type = BDADDR_BREDR;
+	err = kernel_bind(sock, (struct sockaddr_unsized *)&addr, sizeof(addr));
+	if (err < 0) {
+		BT_ERR("Bind failed %d", err);
+		goto failed;
+	}
+
+	/* Set L2CAP options */
+	sk = sock->sk;
+	lock_sock(sk);
+	/* Set MTU to 0 so L2CAP can auto select the MTU */
+	l2cap_pi(sk)->chan->imtu = 0;
+	release_sock(sk);
+
+	/* Start listening on the socket */
+	err = kernel_listen(sock, 10);
+	if (err) {
+		BT_ERR("Listen failed %d", err);
+		goto failed;
+	}
+
+	/* Add listening session */
+	s = rfcomm_session_add(sock, BT_LISTEN);
+	if (!s) {
+		err = -ENOMEM;
+		goto failed;
+	}
+
+	return 0;
+failed:
+	sock_release(sock);
+	return err;
+}
+
+static void rfcomm_kill_listener(void)
+{
+	struct rfcomm_session *s, *n;
+
+	BT_DBG("");
+
+	rfcomm_lock();
+	list_for_each_entry_safe(s, n, &session_list, list)
+		rfcomm_session_del(s);
+	rfcomm_unlock();
+}
+
+static int rfcomm_run(void *unused)
+{
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	BT_DBG("");
+
+	set_user_nice(current, -10);
+
+	rfcomm_add_listener(BDADDR_ANY);
+
+	add_wait_queue(&rfcomm_wq, &wait);
+	while (!kthread_should_stop()) {
+
+		/* Process stuff */
+		rfcomm_process_sessions();
+
+		wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
+	}
+	remove_wait_queue(&rfcomm_wq, &wait);
+
+	rfcomm_kill_listener();
+
+	return 0;
+}
+
+static void rfcomm_security_cfm(struct hci_conn *conn, u8 status, u8 encrypt)
+{
+	struct rfcomm_session *s;
+	struct rfcomm_dlc *d, *n;
+
+	BT_DBG("conn %p status 0x%02x encrypt 0x%02x", conn, status, encrypt);
+
+	rfcomm_lock();
+
+	s = rfcomm_session_get(&conn->hdev->bdaddr, &conn->dst);
+	if (!s) {
+		rfcomm_unlock();
+		return;
+	}
+
+	list_for_each_entry_safe(d, n, &s->dlcs, list) {
+		if (test_and_clear_bit(RFCOMM_SEC_PENDING, &d->flags)) {
+			rfcomm_dlc_clear_timer(d);
+			if (status || encrypt == 0x00) {
+				set_bit(RFCOMM_ENC_DROP, &d->flags);
+				continue;
+			}
+		}
+
+		if (d->state == BT_CONNECTED && !status && encrypt == 0x00) {
+			if (d->sec_level == BT_SECURITY_MEDIUM) {
+				set_bit(RFCOMM_SEC_PENDING, &d->flags);
+				rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
+				continue;
+			} else if (d->sec_level == BT_SECURITY_HIGH ||
+				   d->sec_level == BT_SECURITY_FIPS) {
+				set_bit(RFCOMM_ENC_DROP, &d->flags);
+				continue;
+			}
+		}
+
+		if (!test_and_clear_bit(RFCOMM_AUTH_PENDING, &d->flags))
+			continue;
+
+		if (!status && hci_conn_check_secure(conn, d->sec_level))
+			set_bit(RFCOMM_AUTH_ACCEPT, &d->flags);
+		else
+			set_bit(RFCOMM_AUTH_REJECT, &d->flags);
+	}
+
+	rfcomm_unlock();
+
+	rfcomm_schedule();
+}
+
+static struct hci_cb rfcomm_cb = {
+	.name		= "RFCOMM",
+	.security_cfm	= rfcomm_security_cfm
+};
+
+static int rfcomm_dlc_debugfs_show(struct seq_file *f, void *x)
+{
+	struct rfcomm_session *s;
+
+	rfcomm_lock();
+
+	list_for_each_entry(s, &session_list, list) {
+		struct l2cap_chan *chan = l2cap_pi(s->sock->sk)->chan;
+		struct rfcomm_dlc *d;
+		list_for_each_entry(d, &s->dlcs, list) {
+			seq_printf(f, "%pMR %pMR %ld %d %d %d %d\n",
+				   &chan->src, &chan->dst,
+				   d->state, d->dlci, d->mtu,
+				   d->rx_credits, d->tx_credits);
+		}
+	}
+
+	rfcomm_unlock();
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(rfcomm_dlc_debugfs);
+
+static struct dentry *rfcomm_dlc_debugfs;
+
+/* ---- Initialization ---- */
+static int __init rfcomm_init(void)
+{
+	int err;
+
+	hci_register_cb(&rfcomm_cb);
+
+	rfcomm_thread = kthread_run(rfcomm_run, NULL, "krfcommd");
+	if (IS_ERR(rfcomm_thread)) {
+		err = PTR_ERR(rfcomm_thread);
+		goto unregister;
+	}
+
+	err = rfcomm_init_ttys();
+	if (err < 0)
+		goto stop;
+
+	err = rfcomm_init_sockets();
+	if (err < 0)
+		goto cleanup;
+
+	BT_INFO("RFCOMM ver %s", VERSION);
+
+	if (IS_ERR_OR_NULL(bt_debugfs))
+		return 0;
+
+	rfcomm_dlc_debugfs = debugfs_create_file("rfcomm_dlc", 0444,
+						 bt_debugfs, NULL,
+						 &rfcomm_dlc_debugfs_fops);
+
+	return 0;
+
+cleanup:
+	rfcomm_cleanup_ttys();
+
+stop:
+	kthread_stop(rfcomm_thread);
+
+unregister:
+	hci_unregister_cb(&rfcomm_cb);
+
+	return err;
+}
+
+static void __exit rfcomm_exit(void)
+{
+	debugfs_remove(rfcomm_dlc_debugfs);
+
+	hci_unregister_cb(&rfcomm_cb);
+
+	kthread_stop(rfcomm_thread);
+
+	rfcomm_cleanup_ttys();
+
+	rfcomm_cleanup_sockets();
+}
+
+module_init(rfcomm_init);
+module_exit(rfcomm_exit);
+
+module_param(disable_cfc, bool, 0644);
+MODULE_PARM_DESC(disable_cfc, "Disable credit based flow control");
+
+module_param(channel_mtu, int, 0644);
+MODULE_PARM_DESC(channel_mtu, "Default MTU for the RFCOMM channel");
+
+module_param(l2cap_ertm, bool, 0644);
+MODULE_PARM_DESC(l2cap_ertm, "Use L2CAP ERTM mode for connection");
+
+MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
+MODULE_DESCRIPTION("Bluetooth RFCOMM ver " VERSION);
+MODULE_VERSION(VERSION);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("bt-proto-3");
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
new file mode 100644
index 000000000..958081adb
--- /dev/null
+++ b/net/bluetooth/rfcomm/sock.c
@@ -0,0 +1,1109 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+   RFCOMM implementation for Linux Bluetooth stack (BlueZ).
+   Copyright (C) 2002 Maxim Krasnyansky <maxk@qualcomm.com>
+   Copyright (C) 2002 Marcel Holtmann <marcel@holtmann.org>
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
+   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
+   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
+   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
+   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
+   SOFTWARE IS DISCLAIMED.
+*/
+
+/*
+ * RFCOMM sockets.
+ */
+#include <linux/compat.h>
+#include <linux/export.h>
+#include <linux/debugfs.h>
+#include <linux/sched/signal.h>
+#include <linux/uio.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+#include <net/bluetooth/l2cap.h>
+#include <net/bluetooth/rfcomm.h>
+
+static const struct proto_ops rfcomm_sock_ops;
+
+static struct bt_sock_list rfcomm_sk_list = {
+	.lock = __RW_LOCK_UNLOCKED(rfcomm_sk_list.lock)
+};
+
+static void rfcomm_sock_close(struct sock *sk);
+static void rfcomm_sock_kill(struct sock *sk);
+
+/* ---- DLC callbacks ----
+ *
+ * called under rfcomm_dlc_lock()
+ */
+static void rfcomm_sk_data_ready(struct rfcomm_dlc *d, struct sk_buff *skb)
+{
+	struct sock *sk = d->owner;
+	if (!sk)
+		return;
+
+	atomic_add(skb->len, &sk->sk_rmem_alloc);
+	skb_queue_tail(&sk->sk_receive_queue, skb);
+	sk->sk_data_ready(sk);
+
+	if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
+		rfcomm_dlc_throttle(d);
+}
+
+static void rfcomm_sk_state_change(struct rfcomm_dlc *d, int err)
+	__must_hold(&d->lock)
+{
+	struct sock *sk = d->owner, *parent;
+
+	if (!sk)
+		return;
+
+	BT_DBG("dlc %p state %ld err %d", d, d->state, err);
+
+	lock_sock(sk);
+
+	if (err)
+		sk->sk_err = err;
+
+	sk->sk_state = d->state;
+
+	parent = bt_sk(sk)->parent;
+	if (parent) {
+		if (d->state == BT_CLOSED) {
+			sock_set_flag(sk, SOCK_ZAPPED);
+			bt_accept_unlink(sk);
+		}
+		parent->sk_data_ready(parent);
+	} else {
+		if (d->state == BT_CONNECTED)
+			rfcomm_session_getaddr(d->session,
+					       &rfcomm_pi(sk)->src, NULL);
+		sk->sk_state_change(sk);
+	}
+
+	release_sock(sk);
+
+	if (parent && sock_flag(sk, SOCK_ZAPPED)) {
+		/* We have to drop DLC lock here, otherwise
+		 * rfcomm_sock_destruct() will dead lock. */
+		rfcomm_dlc_unlock(d);
+		rfcomm_sock_kill(sk);
+		rfcomm_dlc_lock(d);
+	}
+}
+
+/* ---- Socket functions ---- */
+static struct sock *__rfcomm_get_listen_sock_by_addr(u8 channel, bdaddr_t *src)
+{
+	struct sock *sk = NULL;
+
+	sk_for_each(sk, &rfcomm_sk_list.head) {
+		if (rfcomm_pi(sk)->channel != channel)
+			continue;
+
+		if (bacmp(&rfcomm_pi(sk)->src, src))
+			continue;
+
+		if (sk->sk_state == BT_BOUND || sk->sk_state == BT_LISTEN)
+			break;
+	}
+
+	return sk ? sk : NULL;
+}
+
+/* Find socket with channel and source bdaddr.
+ * Returns closest match with an extra reference held.
+ */
+static struct sock *rfcomm_get_sock_by_channel(int state, u8 channel, bdaddr_t *src)
+{
+	struct sock *sk = NULL, *sk1 = NULL;
+
+	read_lock(&rfcomm_sk_list.lock);
+
+	sk_for_each(sk, &rfcomm_sk_list.head) {
+		if (state && sk->sk_state != state)
+			continue;
+
+		if (rfcomm_pi(sk)->channel == channel) {
+			/* Exact match. */
+			if (!bacmp(&rfcomm_pi(sk)->src, src)) {
+				sock_hold(sk);
+				break;
+			}
+
+			/* Closest match */
+			if (!bacmp(&rfcomm_pi(sk)->src, BDADDR_ANY)) {
+				if (sk1)
+					sock_put(sk1);
+
+				sk1 = sk;
+				sock_hold(sk1);
+			}
+		}
+	}
+
+	if (sk && sk1)
+		sock_put(sk1);
+
+	read_unlock(&rfcomm_sk_list.lock);
+
+	return sk ? sk : sk1;
+}
+
+static void rfcomm_sock_destruct(struct sock *sk)
+{
+	struct rfcomm_dlc *d = rfcomm_pi(sk)->dlc;
+
+	BT_DBG("sk %p dlc %p", sk, d);
+
+	skb_queue_purge(&sk->sk_receive_queue);
+	skb_queue_purge(&sk->sk_write_queue);
+
+	rfcomm_dlc_lock(d);
+	rfcomm_pi(sk)->dlc = NULL;
+
+	/* Detach DLC if it's owned by this socket */
+	if (d->owner == sk)
+		d->owner = NULL;
+	rfcomm_dlc_unlock(d);
+
+	rfcomm_dlc_put(d);
+}
+
+static void rfcomm_sock_cleanup_listen(struct sock *parent)
+{
+	struct sock *sk;
+
+	BT_DBG("parent %p", parent);
+
+	/* Close not yet accepted dlcs */
+	while ((sk = bt_accept_dequeue(parent, NULL))) {
+		rfcomm_sock_close(sk);
+		rfcomm_sock_kill(sk);
+		/* Drop the reference handed back by bt_accept_dequeue(). */
+		sock_put(sk);
+	}
+
+	parent->sk_state  = BT_CLOSED;
+	sock_set_flag(parent, SOCK_ZAPPED);
+}
+
+/* Kill socket (only if zapped and orphan)
+ * Must be called on unlocked socket.
+ */
+static void rfcomm_sock_kill(struct sock *sk)
+{
+	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
+		return;
+
+	BT_DBG("sk %p state %d refcnt %d", sk, sk->sk_state, refcount_read(&sk->sk_refcnt));
+
+	/* Kill poor orphan */
+	bt_sock_unlink(&rfcomm_sk_list, sk);
+	sock_set_flag(sk, SOCK_DEAD);
+	sock_put(sk);
+}
+
+static void __rfcomm_sock_close(struct sock *sk)
+{
+	struct rfcomm_dlc *d = rfcomm_pi(sk)->dlc;
+
+	BT_DBG("sk %p state %d socket %p", sk, sk->sk_state, sk->sk_socket);
+
+	switch (sk->sk_state) {
+	case BT_LISTEN:
+		rfcomm_sock_cleanup_listen(sk);
+		break;
+
+	case BT_CONNECT:
+	case BT_CONNECT2:
+	case BT_CONFIG:
+	case BT_CONNECTED:
+		rfcomm_dlc_close(d, 0);
+		fallthrough;
+
+	default:
+		sock_set_flag(sk, SOCK_ZAPPED);
+		break;
+	}
+}
+
+/* Close socket.
+ * Must be called on unlocked socket.
+ */
+static void rfcomm_sock_close(struct sock *sk)
+{
+	lock_sock(sk);
+	__rfcomm_sock_close(sk);
+	release_sock(sk);
+}
+
+static void rfcomm_sock_init(struct sock *sk, struct sock *parent)
+{
+	struct rfcomm_pinfo *pi = rfcomm_pi(sk);
+
+	BT_DBG("sk %p", sk);
+
+	if (parent) {
+		sk->sk_type = parent->sk_type;
+		pi->dlc->defer_setup = test_bit(BT_SK_DEFER_SETUP,
+						&bt_sk(parent)->flags);
+
+		pi->sec_level = rfcomm_pi(parent)->sec_level;
+		pi->role_switch = rfcomm_pi(parent)->role_switch;
+
+		security_sk_clone(parent, sk);
+	} else {
+		pi->dlc->defer_setup = 0;
+
+		pi->sec_level = BT_SECURITY_LOW;
+		pi->role_switch = 0;
+	}
+
+	pi->dlc->sec_level = pi->sec_level;
+	pi->dlc->role_switch = pi->role_switch;
+}
+
+static struct proto rfcomm_proto = {
+	.name		= "RFCOMM",
+	.owner		= THIS_MODULE,
+	.obj_size	= sizeof(struct rfcomm_pinfo)
+};
+
+static struct sock *rfcomm_sock_alloc(struct net *net, struct socket *sock,
+				      int proto, gfp_t prio, int kern)
+{
+	struct rfcomm_dlc *d;
+	struct sock *sk;
+
+	d = rfcomm_dlc_alloc(prio);
+	if (!d)
+		return NULL;
+
+	sk = bt_sock_alloc(net, sock, &rfcomm_proto, proto, prio, kern);
+	if (!sk) {
+		rfcomm_dlc_free(d);
+		return NULL;
+	}
+
+	d->data_ready   = rfcomm_sk_data_ready;
+	d->state_change = rfcomm_sk_state_change;
+
+	rfcomm_pi(sk)->dlc = d;
+	d->owner = sk;
+
+	sk->sk_destruct = rfcomm_sock_destruct;
+	sk->sk_sndtimeo = RFCOMM_CONN_TIMEOUT;
+
+	sk->sk_sndbuf = RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 10;
+	sk->sk_rcvbuf = RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 10;
+
+	bt_sock_link(&rfcomm_sk_list, sk);
+
+	BT_DBG("sk %p", sk);
+	return sk;
+}
+
+static int rfcomm_sock_create(struct net *net, struct socket *sock,
+			      int protocol, int kern)
+{
+	struct sock *sk;
+
+	BT_DBG("sock %p", sock);
+
+	sock->state = SS_UNCONNECTED;
+
+	if (sock->type != SOCK_STREAM && sock->type != SOCK_RAW)
+		return -ESOCKTNOSUPPORT;
+
+	sock->ops = &rfcomm_sock_ops;
+
+	sk = rfcomm_sock_alloc(net, sock, protocol, GFP_ATOMIC, kern);
+	if (!sk)
+		return -ENOMEM;
+
+	rfcomm_sock_init(sk, NULL);
+	return 0;
+}
+
+static int rfcomm_sock_bind(struct socket *sock, struct sockaddr_unsized *addr, int addr_len)
+{
+	struct sockaddr_rc sa;
+	struct sock *sk = sock->sk;
+	int len, err = 0;
+
+	if (!addr || addr_len < offsetofend(struct sockaddr, sa_family) ||
+	    addr->sa_family != AF_BLUETOOTH)
+		return -EINVAL;
+
+	memset(&sa, 0, sizeof(sa));
+	len = min_t(unsigned int, sizeof(sa), addr_len);
+	memcpy(&sa, addr, len);
+
+	BT_DBG("sk %p %pMR", sk, &sa.rc_bdaddr);
+
+	lock_sock(sk);
+
+	if (sk->sk_state != BT_OPEN) {
+		err = -EBADFD;
+		goto done;
+	}
+
+	if (sk->sk_type != SOCK_STREAM) {
+		err = -EINVAL;
+		goto done;
+	}
+
+	write_lock(&rfcomm_sk_list.lock);
+
+	if (sa.rc_channel &&
+	    __rfcomm_get_listen_sock_by_addr(sa.rc_channel, &sa.rc_bdaddr)) {
+		err = -EADDRINUSE;
+	} else {
+		/* Save source address */
+		bacpy(&rfcomm_pi(sk)->src, &sa.rc_bdaddr);
+		rfcomm_pi(sk)->channel = sa.rc_channel;
+		sk->sk_state = BT_BOUND;
+	}
+
+	write_unlock(&rfcomm_sk_list.lock);
+
+done:
+	release_sock(sk);
+	return err;
+}
+
+static int rfcomm_sock_connect(struct socket *sock, struct sockaddr_unsized *addr,
+			       int alen, int flags)
+{
+	struct sockaddr_rc *sa = (struct sockaddr_rc *) addr;
+	struct sock *sk = sock->sk;
+	struct rfcomm_dlc *d = rfcomm_pi(sk)->dlc;
+	int err = 0;
+
+	BT_DBG("sk %p", sk);
+
+	if (alen < sizeof(struct sockaddr_rc) ||
+	    addr->sa_family != AF_BLUETOOTH)
+		return -EINVAL;
+
+	sock_hold(sk);
+	lock_sock(sk);
+
+	if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND) {
+		err = -EBADFD;
+		goto done;
+	}
+
+	if (sk->sk_type != SOCK_STREAM) {
+		err = -EINVAL;
+		goto done;
+	}
+
+	sk->sk_state = BT_CONNECT;
+	bacpy(&rfcomm_pi(sk)->dst, &sa->rc_bdaddr);
+	rfcomm_pi(sk)->channel = sa->rc_channel;
+
+	d->sec_level = rfcomm_pi(sk)->sec_level;
+	d->role_switch = rfcomm_pi(sk)->role_switch;
+
+	/* Drop sock lock to avoid potential deadlock with the RFCOMM lock */
+	release_sock(sk);
+	err = rfcomm_dlc_open(d, &rfcomm_pi(sk)->src, &sa->rc_bdaddr,
+			      sa->rc_channel);
+	lock_sock(sk);
+	if (!err && !sock_flag(sk, SOCK_ZAPPED))
+		err = bt_sock_wait_state(sk, BT_CONNECTED,
+				sock_sndtimeo(sk, flags & O_NONBLOCK));
+
+done:
+	release_sock(sk);
+	sock_put(sk);
+	return err;
+}
+
+static int rfcomm_sock_listen(struct socket *sock, int backlog)
+{
+	struct sock *sk = sock->sk;
+	int err = 0;
+
+	BT_DBG("sk %p backlog %d", sk, backlog);
+
+	lock_sock(sk);
+
+	if (sk->sk_state != BT_BOUND) {
+		err = -EBADFD;
+		goto done;
+	}
+
+	if (sk->sk_type != SOCK_STREAM) {
+		err = -EINVAL;
+		goto done;
+	}
+
+	if (!rfcomm_pi(sk)->channel) {
+		bdaddr_t *src = &rfcomm_pi(sk)->src;
+		u8 channel;
+
+		err = -EINVAL;
+
+		write_lock(&rfcomm_sk_list.lock);
+
+		for (channel = 1; channel < 31; channel++)
+			if (!__rfcomm_get_listen_sock_by_addr(channel, src)) {
+				rfcomm_pi(sk)->channel = channel;
+				err = 0;
+				break;
+			}
+
+		write_unlock(&rfcomm_sk_list.lock);
+
+		if (err < 0)
+			goto done;
+	}
+
+	sk->sk_max_ack_backlog = backlog;
+	sk->sk_ack_backlog = 0;
+	sk->sk_state = BT_LISTEN;
+
+done:
+	release_sock(sk);
+	return err;
+}
+
+static int rfcomm_sock_accept(struct socket *sock, struct socket *newsock,
+			      struct proto_accept_arg *arg)
+{
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	struct sock *sk = sock->sk, *nsk;
+	long timeo;
+	int err = 0;
+
+	lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
+
+	if (sk->sk_type != SOCK_STREAM) {
+		err = -EINVAL;
+		goto done;
+	}
+
+	timeo = sock_rcvtimeo(sk, arg->flags & O_NONBLOCK);
+
+	BT_DBG("sk %p timeo %ld", sk, timeo);
+
+	/* Wait for an incoming connection. (wake-one). */
+	add_wait_queue_exclusive(sk_sleep(sk), &wait);
+	while (1) {
+		if (sk->sk_state != BT_LISTEN) {
+			err = -EBADFD;
+			break;
+		}
+
+		nsk = bt_accept_dequeue(sk, newsock);
+		if (nsk) {
+			/* Drop the bridging ref from bt_accept_dequeue();
+			 * the grafted socket keeps nsk alive from here.
+			 */
+			sock_put(nsk);
+			break;
+		}
+
+		if (!timeo) {
+			err = -EAGAIN;
+			break;
+		}
+
+		if (signal_pending(current)) {
+			err = sock_intr_errno(timeo);
+			break;
+		}
+
+		release_sock(sk);
+
+		timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
+
+		lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
+	}
+	remove_wait_queue(sk_sleep(sk), &wait);
+
+	if (err)
+		goto done;
+
+	newsock->state = SS_CONNECTED;
+
+	BT_DBG("new socket %p", nsk);
+
+done:
+	release_sock(sk);
+	return err;
+}
+
+static int rfcomm_sock_getname(struct socket *sock, struct sockaddr *addr, int peer)
+{
+	struct sockaddr_rc *sa = (struct sockaddr_rc *) addr;
+	struct sock *sk = sock->sk;
+
+	BT_DBG("sock %p, sk %p", sock, sk);
+
+	if (peer && sk->sk_state != BT_CONNECTED &&
+	    sk->sk_state != BT_CONNECT && sk->sk_state != BT_CONNECT2)
+		return -ENOTCONN;
+
+	memset(sa, 0, sizeof(*sa));
+	sa->rc_family  = AF_BLUETOOTH;
+	sa->rc_channel = rfcomm_pi(sk)->channel;
+	if (peer)
+		bacpy(&sa->rc_bdaddr, &rfcomm_pi(sk)->dst);
+	else
+		bacpy(&sa->rc_bdaddr, &rfcomm_pi(sk)->src);
+
+	return sizeof(struct sockaddr_rc);
+}
+
+static int rfcomm_sock_sendmsg(struct socket *sock, struct msghdr *msg,
+			       size_t len)
+{
+	struct sock *sk = sock->sk;
+	struct rfcomm_dlc *d = rfcomm_pi(sk)->dlc;
+	struct sk_buff *skb;
+	int sent;
+
+	if (test_bit(RFCOMM_DEFER_SETUP, &d->flags))
+		return -ENOTCONN;
+
+	if (msg->msg_flags & MSG_OOB)
+		return -EOPNOTSUPP;
+
+	if (sk->sk_shutdown & SEND_SHUTDOWN)
+		return -EPIPE;
+
+	BT_DBG("sock %p, sk %p", sock, sk);
+
+	lock_sock(sk);
+
+	sent = bt_sock_wait_ready(sk, msg->msg_flags);
+
+	release_sock(sk);
+
+	if (sent)
+		return sent;
+
+	skb = bt_skb_sendmmsg(sk, msg, len, d->mtu, RFCOMM_SKB_HEAD_RESERVE,
+			      RFCOMM_SKB_TAIL_RESERVE);
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	sent = rfcomm_dlc_send(d, skb);
+	if (sent < 0)
+		kfree_skb(skb);
+
+	return sent;
+}
+
+static int rfcomm_sock_recvmsg(struct socket *sock, struct msghdr *msg,
+			       size_t size, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct rfcomm_dlc *d = rfcomm_pi(sk)->dlc;
+	int len;
+
+	if (test_and_clear_bit(RFCOMM_DEFER_SETUP, &d->flags)) {
+		rfcomm_dlc_accept(d);
+		return 0;
+	}
+
+	len = bt_sock_stream_recvmsg(sock, msg, size, flags);
+
+	lock_sock(sk);
+	if (!(flags & MSG_PEEK) && len > 0)
+		atomic_sub(len, &sk->sk_rmem_alloc);
+
+	if (atomic_read(&sk->sk_rmem_alloc) <= (sk->sk_rcvbuf >> 2))
+		rfcomm_dlc_unthrottle(rfcomm_pi(sk)->dlc);
+	release_sock(sk);
+
+	return len;
+}
+
+static int rfcomm_sock_setsockopt_old(struct socket *sock, int optname,
+		sockptr_t optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	int err = 0;
+	u32 opt;
+
+	BT_DBG("sk %p", sk);
+
+	lock_sock(sk);
+
+	switch (optname) {
+	case RFCOMM_LM:
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		if (err)
+			break;
+
+		if (opt & RFCOMM_LM_FIPS) {
+			err = -EINVAL;
+			break;
+		}
+
+		if (opt & RFCOMM_LM_AUTH)
+			rfcomm_pi(sk)->sec_level = BT_SECURITY_LOW;
+		if (opt & RFCOMM_LM_ENCRYPT)
+			rfcomm_pi(sk)->sec_level = BT_SECURITY_MEDIUM;
+		if (opt & RFCOMM_LM_SECURE)
+			rfcomm_pi(sk)->sec_level = BT_SECURITY_HIGH;
+
+		rfcomm_pi(sk)->role_switch = (opt & RFCOMM_LM_MASTER);
+		break;
+
+	default:
+		err = -ENOPROTOOPT;
+		break;
+	}
+
+	release_sock(sk);
+	return err;
+}
+
+static int rfcomm_sock_setsockopt(struct socket *sock, int level, int optname,
+		sockptr_t optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	struct bt_security sec;
+	int err = 0;
+	u32 opt;
+
+	BT_DBG("sk %p", sk);
+
+	if (level == SOL_RFCOMM)
+		return rfcomm_sock_setsockopt_old(sock, optname, optval, optlen);
+
+	if (level != SOL_BLUETOOTH)
+		return -ENOPROTOOPT;
+
+	lock_sock(sk);
+
+	switch (optname) {
+	case BT_SECURITY:
+		if (sk->sk_type != SOCK_STREAM) {
+			err = -EINVAL;
+			break;
+		}
+
+		sec.level = BT_SECURITY_LOW;
+
+		err = copy_safe_from_sockptr(&sec, sizeof(sec), optval, optlen);
+		if (err)
+			break;
+
+		if (sec.level > BT_SECURITY_HIGH) {
+			err = -EINVAL;
+			break;
+		}
+
+		rfcomm_pi(sk)->sec_level = sec.level;
+		break;
+
+	case BT_DEFER_SETUP:
+		if (sk->sk_state != BT_BOUND && sk->sk_state != BT_LISTEN) {
+			err = -EINVAL;
+			break;
+		}
+
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		if (err)
+			break;
+
+		if (opt)
+			set_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags);
+		else
+			clear_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags);
+
+		break;
+
+	default:
+		err = -ENOPROTOOPT;
+		break;
+	}
+
+	release_sock(sk);
+	return err;
+}
+
+static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname,
+				      sockopt_t *sopt)
+{
+	struct sock *sk = sock->sk;
+	struct sock *l2cap_sk;
+	struct l2cap_conn *conn;
+	struct rfcomm_conninfo cinfo;
+	int err = 0;
+	size_t len;
+	u32 opt;
+
+	BT_DBG("sk %p", sk);
+
+	len = sopt->optlen;
+
+	lock_sock(sk);
+
+	switch (optname) {
+	case RFCOMM_LM:
+		switch (rfcomm_pi(sk)->sec_level) {
+		case BT_SECURITY_LOW:
+			opt = RFCOMM_LM_AUTH;
+			break;
+		case BT_SECURITY_MEDIUM:
+			opt = RFCOMM_LM_AUTH | RFCOMM_LM_ENCRYPT;
+			break;
+		case BT_SECURITY_HIGH:
+			opt = RFCOMM_LM_AUTH | RFCOMM_LM_ENCRYPT |
+			      RFCOMM_LM_SECURE;
+			break;
+		case BT_SECURITY_FIPS:
+			opt = RFCOMM_LM_AUTH | RFCOMM_LM_ENCRYPT |
+			      RFCOMM_LM_SECURE | RFCOMM_LM_FIPS;
+			break;
+		default:
+			opt = 0;
+			break;
+		}
+
+		if (rfcomm_pi(sk)->role_switch)
+			opt |= RFCOMM_LM_MASTER;
+
+		if (copy_to_iter(&opt, sizeof(opt), &sopt->iter_out) !=
+		    sizeof(opt))
+			err = -EFAULT;
+
+		break;
+
+	case RFCOMM_CONNINFO:
+		if (sk->sk_state != BT_CONNECTED &&
+					!rfcomm_pi(sk)->dlc->defer_setup) {
+			err = -ENOTCONN;
+			break;
+		}
+
+		l2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk;
+		conn = l2cap_pi(l2cap_sk)->chan->conn;
+
+		memset(&cinfo, 0, sizeof(cinfo));
+		cinfo.hci_handle = conn->hcon->handle;
+		memcpy(cinfo.dev_class, conn->hcon->dev_class, 3);
+
+		len = min(len, sizeof(cinfo));
+		if (copy_to_iter(&cinfo, len, &sopt->iter_out) != len)
+			err = -EFAULT;
+
+		break;
+
+	default:
+		err = -ENOPROTOOPT;
+		break;
+	}
+
+	release_sock(sk);
+	return err;
+}
+
+static int rfcomm_sock_getsockopt(struct socket *sock, int level, int optname,
+				  sockopt_t *sopt)
+{
+	struct sock *sk = sock->sk;
+	struct bt_security sec;
+	int err = 0;
+	size_t len;
+	u32 opt;
+
+	BT_DBG("sk %p", sk);
+
+	if (level == SOL_RFCOMM)
+		return rfcomm_sock_getsockopt_old(sock, optname, sopt);
+
+	if (level != SOL_BLUETOOTH)
+		return -ENOPROTOOPT;
+
+	len = sopt->optlen;
+
+	lock_sock(sk);
+
+	switch (optname) {
+	case BT_SECURITY:
+		if (sk->sk_type != SOCK_STREAM) {
+			err = -EINVAL;
+			break;
+		}
+
+		sec.level = rfcomm_pi(sk)->sec_level;
+		sec.key_size = 0;
+
+		len = min(len, sizeof(sec));
+		if (copy_to_iter(&sec, len, &sopt->iter_out) != len)
+			err = -EFAULT;
+
+		break;
+
+	case BT_DEFER_SETUP:
+		if (sk->sk_state != BT_BOUND && sk->sk_state != BT_LISTEN) {
+			err = -EINVAL;
+			break;
+		}
+
+		opt = test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags);
+		if (copy_to_iter(&opt, sizeof(opt), &sopt->iter_out) !=
+		    sizeof(opt))
+			err = -EFAULT;
+
+		break;
+
+	default:
+		err = -ENOPROTOOPT;
+		break;
+	}
+
+	release_sock(sk);
+	return err;
+}
+
+static int rfcomm_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	struct sock *sk __maybe_unused = sock->sk;
+	int err;
+
+	BT_DBG("sk %p cmd %x arg %lx", sk, cmd, arg);
+
+	err = bt_sock_ioctl(sock, cmd, arg);
+
+	if (err == -ENOIOCTLCMD) {
+#ifdef CONFIG_BT_RFCOMM_TTY
+		err = rfcomm_dev_ioctl(sk, cmd, (void __user *) arg);
+#else
+		err = -EOPNOTSUPP;
+#endif
+	}
+
+	return err;
+}
+
+#ifdef CONFIG_COMPAT
+static int rfcomm_sock_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	return rfcomm_sock_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static int rfcomm_sock_shutdown(struct socket *sock, int how)
+{
+	struct sock *sk = sock->sk;
+	int err = 0;
+
+	BT_DBG("sock %p, sk %p", sock, sk);
+
+	if (!sk)
+		return 0;
+
+	lock_sock(sk);
+	if (!sk->sk_shutdown) {
+		sk->sk_shutdown = SHUTDOWN_MASK;
+
+		release_sock(sk);
+		__rfcomm_sock_close(sk);
+		lock_sock(sk);
+
+		if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime &&
+		    !(current->flags & PF_EXITING))
+			err = bt_sock_wait_state(sk, BT_CLOSED, sk->sk_lingertime);
+	}
+	release_sock(sk);
+	return err;
+}
+
+static int rfcomm_sock_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	int err;
+
+	BT_DBG("sock %p, sk %p", sock, sk);
+
+	if (!sk)
+		return 0;
+
+	err = rfcomm_sock_shutdown(sock, 2);
+
+	sock_orphan(sk);
+	rfcomm_sock_kill(sk);
+	return err;
+}
+
+/* ---- RFCOMM core layer callbacks ----
+ *
+ * called under rfcomm_lock()
+ */
+int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc **d)
+{
+	struct sock *sk, *parent;
+	bdaddr_t src, dst;
+	bool defer_setup = false;
+	int result = 0;
+
+	BT_DBG("session %p channel %d", s, channel);
+
+	rfcomm_session_getaddr(s, &src, &dst);
+
+	/* Check if we have socket listening on channel */
+	parent = rfcomm_get_sock_by_channel(BT_LISTEN, channel, &src);
+	if (!parent)
+		return 0;
+
+	lock_sock(parent);
+
+	if (parent->sk_state != BT_LISTEN)
+		goto done;
+
+	defer_setup = test_bit(BT_SK_DEFER_SETUP, &bt_sk(parent)->flags);
+
+	/* Check for backlog size */
+	if (sk_acceptq_is_full(parent)) {
+		BT_DBG("backlog full %d", parent->sk_ack_backlog);
+		goto done;
+	}
+
+	sk = rfcomm_sock_alloc(sock_net(parent), NULL, BTPROTO_RFCOMM, GFP_ATOMIC, 0);
+	if (!sk)
+		goto done;
+
+	bt_sock_reclassify_lock(sk, BTPROTO_RFCOMM);
+
+	rfcomm_sock_init(sk, parent);
+	bacpy(&rfcomm_pi(sk)->src, &src);
+	bacpy(&rfcomm_pi(sk)->dst, &dst);
+	rfcomm_pi(sk)->channel = channel;
+
+	sk->sk_state = BT_CONFIG;
+	bt_accept_enqueue(parent, sk, true);
+
+	/* Accept connection and return socket DLC */
+	*d = rfcomm_pi(sk)->dlc;
+	result = 1;
+
+done:
+	release_sock(parent);
+
+	if (defer_setup)
+		parent->sk_state_change(parent);
+
+	sock_put(parent);
+
+	return result;
+}
+
+static int rfcomm_sock_debugfs_show(struct seq_file *f, void *p)
+{
+	struct sock *sk;
+
+	read_lock(&rfcomm_sk_list.lock);
+
+	sk_for_each(sk, &rfcomm_sk_list.head) {
+		seq_printf(f, "%pMR %pMR %d %d\n",
+			   &rfcomm_pi(sk)->src, &rfcomm_pi(sk)->dst,
+			   sk->sk_state, rfcomm_pi(sk)->channel);
+	}
+
+	read_unlock(&rfcomm_sk_list.lock);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(rfcomm_sock_debugfs);
+
+static struct dentry *rfcomm_sock_debugfs;
+
+static const struct proto_ops rfcomm_sock_ops = {
+	.family		= PF_BLUETOOTH,
+	.owner		= THIS_MODULE,
+	.release	= rfcomm_sock_release,
+	.bind		= rfcomm_sock_bind,
+	.connect	= rfcomm_sock_connect,
+	.listen		= rfcomm_sock_listen,
+	.accept		= rfcomm_sock_accept,
+	.getname	= rfcomm_sock_getname,
+	.sendmsg	= rfcomm_sock_sendmsg,
+	.recvmsg	= rfcomm_sock_recvmsg,
+	.shutdown	= rfcomm_sock_shutdown,
+	.setsockopt	= rfcomm_sock_setsockopt,
+	.getsockopt_iter = rfcomm_sock_getsockopt,
+	.ioctl		= rfcomm_sock_ioctl,
+	.gettstamp	= sock_gettstamp,
+	.poll		= bt_sock_poll,
+	.socketpair	= sock_no_socketpair,
+	.mmap		= sock_no_mmap,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= rfcomm_sock_compat_ioctl,
+#endif
+};
+
+static const struct net_proto_family rfcomm_sock_family_ops = {
+	.family		= PF_BLUETOOTH,
+	.owner		= THIS_MODULE,
+	.create		= rfcomm_sock_create
+};
+
+int __init rfcomm_init_sockets(void)
+{
+	int err;
+
+	BUILD_BUG_ON(sizeof(struct sockaddr_rc) > sizeof(struct sockaddr));
+
+	err = proto_register(&rfcomm_proto, 0);
+	if (err < 0)
+		return err;
+
+	err = bt_sock_register(BTPROTO_RFCOMM, &rfcomm_sock_family_ops);
+	if (err < 0) {
+		BT_ERR("RFCOMM socket layer registration failed");
+		goto error;
+	}
+
+	err = bt_procfs_init(&init_net, "rfcomm", &rfcomm_sk_list, NULL);
+	if (err < 0) {
+		BT_ERR("Failed to create RFCOMM proc file");
+		bt_sock_unregister(BTPROTO_RFCOMM);
+		goto error;
+	}
+
+	BT_INFO("RFCOMM socket layer initialized");
+
+	if (IS_ERR_OR_NULL(bt_debugfs))
+		return 0;
+
+	rfcomm_sock_debugfs = debugfs_create_file("rfcomm", 0444,
+						  bt_debugfs, NULL,
+						  &rfcomm_sock_debugfs_fops);
+
+	return 0;
+
+error:
+	proto_unregister(&rfcomm_proto);
+	return err;
+}
+
+void __exit rfcomm_cleanup_sockets(void)
+{
+	bt_procfs_cleanup(&init_net, "rfcomm");
+
+	debugfs_remove(rfcomm_sock_debugfs);
+
+	bt_sock_unregister(BTPROTO_RFCOMM);
+
+	proto_unregister(&rfcomm_proto);
+}
diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
new file mode 100644
index 000000000..b2c106039
--- /dev/null
+++ b/net/bluetooth/rfcomm/tty.c
@@ -0,0 +1,1147 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+   RFCOMM implementation for Linux Bluetooth stack (BlueZ).
+   Copyright (C) 2002 Maxim Krasnyansky <maxk@qualcomm.com>
+   Copyright (C) 2002 Marcel Holtmann <marcel@holtmann.org>
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
+   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
+   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
+   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
+   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
+   SOFTWARE IS DISCLAIMED.
+*/
+
+/*
+ * RFCOMM TTY.
+ */
+
+#include <linux/module.h>
+
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+#include <net/bluetooth/rfcomm.h>
+
+#define RFCOMM_TTY_PORTS RFCOMM_MAX_DEV	/* whole lotta rfcomm devices */
+#define RFCOMM_TTY_MAJOR 216		/* device node major id of the usb/bluetooth.c driver */
+#define RFCOMM_TTY_MINOR 0
+
+static DEFINE_MUTEX(rfcomm_ioctl_mutex);
+static struct tty_driver *rfcomm_tty_driver;
+
+struct rfcomm_dev {
+	struct tty_port		port;
+	struct list_head	list;
+
+	char			name[12];
+	int			id;
+	unsigned long		flags;
+	int			err;
+
+	unsigned long		status;		/* don't export to userspace */
+
+	bdaddr_t		src;
+	bdaddr_t		dst;
+	u8			channel;
+
+	uint			modem_status;
+
+	struct rfcomm_dlc	*dlc;
+
+	struct device		*tty_dev;
+
+	atomic_t		wmem_alloc;
+
+	struct sk_buff_head	pending;
+};
+
+static LIST_HEAD(rfcomm_dev_list);
+static DEFINE_MUTEX(rfcomm_dev_lock);
+
+static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb);
+static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err);
+static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig);
+
+/* ---- Device functions ---- */
+
+static void rfcomm_dev_destruct(struct tty_port *port)
+{
+	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
+	struct rfcomm_dlc *dlc = dev->dlc;
+
+	BT_DBG("dev %p dlc %p", dev, dlc);
+
+	rfcomm_dlc_lock(dlc);
+	/* Detach DLC if it's owned by this dev */
+	if (dlc->owner == dev)
+		dlc->owner = NULL;
+	rfcomm_dlc_unlock(dlc);
+
+	rfcomm_dlc_put(dlc);
+
+	if (dev->tty_dev)
+		tty_unregister_device(rfcomm_tty_driver, dev->id);
+
+	mutex_lock(&rfcomm_dev_lock);
+	list_del(&dev->list);
+	mutex_unlock(&rfcomm_dev_lock);
+
+	kfree(dev);
+
+	/* It's safe to call module_put() here because socket still
+	   holds reference to this module. */
+	module_put(THIS_MODULE);
+}
+
+/* device-specific initialization: open the dlc */
+static int rfcomm_dev_activate(struct tty_port *port, struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
+	int err;
+
+	err = rfcomm_dlc_open(dev->dlc, &dev->src, &dev->dst, dev->channel);
+	if (err)
+		set_bit(TTY_IO_ERROR, &tty->flags);
+	return err;
+}
+
+/* we block the open until the dlc->state becomes BT_CONNECTED */
+static bool rfcomm_dev_carrier_raised(struct tty_port *port)
+{
+	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
+
+	return (dev->dlc->state == BT_CONNECTED);
+}
+
+/* device-specific cleanup: close the dlc */
+static void rfcomm_dev_shutdown(struct tty_port *port)
+{
+	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
+
+	if (dev->tty_dev->parent)
+		device_move(dev->tty_dev, NULL, DPM_ORDER_DEV_LAST);
+
+	/* close the dlc */
+	rfcomm_dlc_close(dev->dlc, 0);
+}
+
+static const struct tty_port_operations rfcomm_port_ops = {
+	.destruct = rfcomm_dev_destruct,
+	.activate = rfcomm_dev_activate,
+	.shutdown = rfcomm_dev_shutdown,
+	.carrier_raised = rfcomm_dev_carrier_raised,
+};
+
+static struct rfcomm_dev *__rfcomm_dev_lookup(int id)
+{
+	struct rfcomm_dev *dev;
+
+	list_for_each_entry(dev, &rfcomm_dev_list, list)
+		if (dev->id == id)
+			return dev;
+
+	return NULL;
+}
+
+static struct rfcomm_dev *rfcomm_dev_get(int id)
+{
+	struct rfcomm_dev *dev;
+
+	mutex_lock(&rfcomm_dev_lock);
+
+	dev = __rfcomm_dev_lookup(id);
+
+	if (dev && !tty_port_get(&dev->port))
+		dev = NULL;
+
+	mutex_unlock(&rfcomm_dev_lock);
+
+	return dev;
+}
+
+static void rfcomm_reparent_device(struct rfcomm_dev *dev)
+{
+	struct hci_dev *hdev;
+	struct hci_conn *conn;
+
+	hdev = hci_get_route(&dev->dst, &dev->src, BDADDR_BREDR);
+	if (!hdev)
+		return;
+
+	/* The lookup results are unsafe to access without the
+	 * hci device lock (FIXME: why is this not documented?)
+	 */
+	hci_dev_lock(hdev);
+	conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, &dev->dst);
+
+	/* Just because the acl link is in the hash table is no
+	 * guarantee the sysfs device has been added ...
+	 */
+	if (conn && device_is_registered(&conn->dev))
+		device_move(dev->tty_dev, &conn->dev, DPM_ORDER_DEV_AFTER_PARENT);
+
+	hci_dev_unlock(hdev);
+	hci_dev_put(hdev);
+}
+
+static ssize_t address_show(struct device *tty_dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct rfcomm_dev *dev = dev_get_drvdata(tty_dev);
+	return sysfs_emit(buf, "%pMR\n", &dev->dst);
+}
+
+static ssize_t channel_show(struct device *tty_dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct rfcomm_dev *dev = dev_get_drvdata(tty_dev);
+	return sysfs_emit(buf, "%d\n", dev->channel);
+}
+
+static DEVICE_ATTR_RO(address);
+static DEVICE_ATTR_RO(channel);
+
+static struct rfcomm_dev *__rfcomm_dev_add(struct rfcomm_dev_req *req,
+					   struct rfcomm_dlc *dlc)
+{
+	struct rfcomm_dev *dev, *entry;
+	struct list_head *head = &rfcomm_dev_list;
+	int err = 0;
+
+	dev = kzalloc_obj(struct rfcomm_dev);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_lock(&rfcomm_dev_lock);
+
+	if (req->dev_id < 0) {
+		dev->id = 0;
+
+		list_for_each_entry(entry, &rfcomm_dev_list, list) {
+			if (entry->id != dev->id)
+				break;
+
+			dev->id++;
+			head = &entry->list;
+		}
+	} else {
+		dev->id = req->dev_id;
+
+		list_for_each_entry(entry, &rfcomm_dev_list, list) {
+			if (entry->id == dev->id) {
+				err = -EADDRINUSE;
+				goto out;
+			}
+
+			if (entry->id > dev->id - 1)
+				break;
+
+			head = &entry->list;
+		}
+	}
+
+	if ((dev->id < 0) || (dev->id > RFCOMM_MAX_DEV - 1)) {
+		err = -ENFILE;
+		goto out;
+	}
+
+	sprintf(dev->name, "rfcomm%d", dev->id);
+
+	list_add(&dev->list, head);
+
+	bacpy(&dev->src, &req->src);
+	bacpy(&dev->dst, &req->dst);
+	dev->channel = req->channel;
+
+	dev->flags = req->flags &
+		((1 << RFCOMM_RELEASE_ONHUP) | (1 << RFCOMM_REUSE_DLC));
+
+	tty_port_init(&dev->port);
+	dev->port.ops = &rfcomm_port_ops;
+
+	skb_queue_head_init(&dev->pending);
+
+	rfcomm_dlc_lock(dlc);
+
+	if (req->flags & (1 << RFCOMM_REUSE_DLC)) {
+		struct sock *sk = dlc->owner;
+		struct sk_buff *skb;
+
+		BUG_ON(!sk);
+
+		rfcomm_dlc_throttle(dlc);
+
+		while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
+			skb_orphan(skb);
+			skb_queue_tail(&dev->pending, skb);
+			atomic_sub(skb->len, &sk->sk_rmem_alloc);
+		}
+	}
+
+	dlc->data_ready   = rfcomm_dev_data_ready;
+	dlc->state_change = rfcomm_dev_state_change;
+	dlc->modem_status = rfcomm_dev_modem_status;
+
+	dlc->owner = dev;
+	dev->dlc   = dlc;
+
+	rfcomm_dev_modem_status(dlc, dlc->remote_v24_sig);
+
+	rfcomm_dlc_unlock(dlc);
+
+	/* It's safe to call __module_get() here because socket already
+	   holds reference to this module. */
+	__module_get(THIS_MODULE);
+
+	mutex_unlock(&rfcomm_dev_lock);
+	return dev;
+
+out:
+	mutex_unlock(&rfcomm_dev_lock);
+	kfree(dev);
+	return ERR_PTR(err);
+}
+
+static int rfcomm_dev_add(struct rfcomm_dev_req *req, struct rfcomm_dlc *dlc)
+{
+	struct rfcomm_dev *dev;
+	struct device *tty;
+
+	BT_DBG("id %d channel %d", req->dev_id, req->channel);
+
+	dev = __rfcomm_dev_add(req, dlc);
+	if (IS_ERR(dev)) {
+		rfcomm_dlc_put(dlc);
+		return PTR_ERR(dev);
+	}
+
+	tty = tty_port_register_device(&dev->port, rfcomm_tty_driver,
+			dev->id, NULL);
+	if (IS_ERR(tty)) {
+		tty_port_put(&dev->port);
+		return PTR_ERR(tty);
+	}
+
+	dev->tty_dev = tty;
+	rfcomm_reparent_device(dev);
+	dev_set_drvdata(dev->tty_dev, dev);
+
+	if (device_create_file(dev->tty_dev, &dev_attr_address) < 0)
+		BT_ERR("Failed to create address attribute");
+
+	if (device_create_file(dev->tty_dev, &dev_attr_channel) < 0)
+		BT_ERR("Failed to create channel attribute");
+
+	return dev->id;
+}
+
+/* ---- Send buffer ---- */
+static inline unsigned int rfcomm_room(struct rfcomm_dev *dev)
+{
+	struct rfcomm_dlc *dlc = dev->dlc;
+
+	/* Limit the outstanding number of packets not yet sent to 40 */
+	int pending = 40 - atomic_read(&dev->wmem_alloc);
+
+	return max(0, pending) * dlc->mtu;
+}
+
+static void rfcomm_wfree(struct sk_buff *skb)
+{
+	struct rfcomm_dev *dev = (void *) skb->sk;
+	atomic_dec(&dev->wmem_alloc);
+	if (test_bit(RFCOMM_TTY_ATTACHED, &dev->flags))
+		tty_port_tty_wakeup(&dev->port);
+	tty_port_put(&dev->port);
+}
+
+static void rfcomm_set_owner_w(struct sk_buff *skb, struct rfcomm_dev *dev)
+{
+	tty_port_get(&dev->port);
+	atomic_inc(&dev->wmem_alloc);
+	skb->sk = (void *) dev;
+	skb->destructor = rfcomm_wfree;
+}
+
+static struct sk_buff *rfcomm_wmalloc(struct rfcomm_dev *dev, unsigned long size, gfp_t priority)
+{
+	struct sk_buff *skb = alloc_skb(size, priority);
+	if (skb)
+		rfcomm_set_owner_w(skb, dev);
+	return skb;
+}
+
+/* ---- Device IOCTLs ---- */
+
+#define NOCAP_FLAGS ((1 << RFCOMM_REUSE_DLC) | (1 << RFCOMM_RELEASE_ONHUP))
+
+static int __rfcomm_create_dev(struct sock *sk, void __user *arg)
+{
+	struct rfcomm_dev_req req;
+	struct rfcomm_dlc *dlc;
+	int id;
+
+	if (copy_from_user(&req, arg, sizeof(req)))
+		return -EFAULT;
+
+	BT_DBG("sk %p dev_id %d flags 0x%x", sk, req.dev_id, req.flags);
+
+	if (req.flags != NOCAP_FLAGS && !capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (req.flags & (1 << RFCOMM_REUSE_DLC)) {
+		/* Socket must be connected */
+		if (sk->sk_state != BT_CONNECTED)
+			return -EBADFD;
+
+		dlc = rfcomm_pi(sk)->dlc;
+		rfcomm_dlc_hold(dlc);
+	} else {
+		/* Validate the channel is unused */
+		dlc = rfcomm_dlc_exists(&req.src, &req.dst, req.channel);
+		if (IS_ERR(dlc))
+			return PTR_ERR(dlc);
+		if (dlc)
+			return -EBUSY;
+		dlc = rfcomm_dlc_alloc(GFP_KERNEL);
+		if (!dlc)
+			return -ENOMEM;
+	}
+
+	id = rfcomm_dev_add(&req, dlc);
+	if (id < 0)
+		return id;
+
+	if (req.flags & (1 << RFCOMM_REUSE_DLC)) {
+		/* DLC is now used by device.
+		 * Socket must be disconnected */
+		sk->sk_state = BT_CLOSED;
+	}
+
+	return id;
+}
+
+static int __rfcomm_release_dev(void __user *arg)
+{
+	struct rfcomm_dev_req req;
+	struct rfcomm_dev *dev;
+
+	if (copy_from_user(&req, arg, sizeof(req)))
+		return -EFAULT;
+
+	BT_DBG("dev_id %d flags 0x%x", req.dev_id, req.flags);
+
+	dev = rfcomm_dev_get(req.dev_id);
+	if (!dev)
+		return -ENODEV;
+
+	if (dev->flags != NOCAP_FLAGS && !capable(CAP_NET_ADMIN)) {
+		tty_port_put(&dev->port);
+		return -EPERM;
+	}
+
+	/* only release once */
+	if (test_and_set_bit(RFCOMM_DEV_RELEASED, &dev->status)) {
+		tty_port_put(&dev->port);
+		return -EALREADY;
+	}
+
+	if (req.flags & (1 << RFCOMM_HANGUP_NOW))
+		rfcomm_dlc_close(dev->dlc, 0);
+
+	/* Shut down TTY synchronously before freeing rfcomm_dev */
+	tty_port_tty_vhangup(&dev->port);
+
+	if (!test_bit(RFCOMM_TTY_OWNED, &dev->status))
+		tty_port_put(&dev->port);
+
+	tty_port_put(&dev->port);
+	return 0;
+}
+
+static int rfcomm_create_dev(struct sock *sk, void __user *arg)
+{
+	int ret;
+
+	mutex_lock(&rfcomm_ioctl_mutex);
+	ret = __rfcomm_create_dev(sk, arg);
+	mutex_unlock(&rfcomm_ioctl_mutex);
+
+	return ret;
+}
+
+static int rfcomm_release_dev(void __user *arg)
+{
+	int ret;
+
+	mutex_lock(&rfcomm_ioctl_mutex);
+	ret = __rfcomm_release_dev(arg);
+	mutex_unlock(&rfcomm_ioctl_mutex);
+
+	return ret;
+}
+
+static int rfcomm_get_dev_list(void __user *arg)
+{
+	struct rfcomm_dev *dev;
+	struct rfcomm_dev_list_req *dl;
+	struct rfcomm_dev_info *di;
+	int n = 0, err;
+	u16 dev_num;
+
+	BT_DBG("");
+
+	if (get_user(dev_num, (u16 __user *) arg))
+		return -EFAULT;
+
+	if (!dev_num || dev_num > (PAGE_SIZE * 4) / sizeof(*di))
+		return -EINVAL;
+
+	dl = kzalloc_flex(*dl, dev_info, dev_num);
+	if (!dl)
+		return -ENOMEM;
+
+	dl->dev_num = dev_num;
+	di = dl->dev_info;
+
+	mutex_lock(&rfcomm_dev_lock);
+
+	list_for_each_entry(dev, &rfcomm_dev_list, list) {
+		if (!tty_port_get(&dev->port))
+			continue;
+		di[n].id      = dev->id;
+		di[n].flags   = dev->flags;
+		di[n].state   = dev->dlc->state;
+		di[n].channel = dev->channel;
+		bacpy(&di[n].src, &dev->src);
+		bacpy(&di[n].dst, &dev->dst);
+		tty_port_put(&dev->port);
+		if (++n >= dev_num)
+			break;
+	}
+
+	mutex_unlock(&rfcomm_dev_lock);
+
+	dl->dev_num = n;
+	err = copy_to_user(arg, dl, struct_size(dl, dev_info, n));
+	kfree(dl);
+
+	return err ? -EFAULT : 0;
+}
+
+static int rfcomm_get_dev_info(void __user *arg)
+{
+	struct rfcomm_dev *dev;
+	struct rfcomm_dev_info di;
+	int err = 0;
+
+	BT_DBG("");
+
+	if (copy_from_user(&di, arg, sizeof(di)))
+		return -EFAULT;
+
+	dev = rfcomm_dev_get(di.id);
+	if (!dev)
+		return -ENODEV;
+
+	di.flags   = dev->flags;
+	di.channel = dev->channel;
+	di.state   = dev->dlc->state;
+	bacpy(&di.src, &dev->src);
+	bacpy(&di.dst, &dev->dst);
+
+	if (copy_to_user(arg, &di, sizeof(di)))
+		err = -EFAULT;
+
+	tty_port_put(&dev->port);
+	return err;
+}
+
+int rfcomm_dev_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	BT_DBG("cmd %d arg %p", cmd, arg);
+
+	switch (cmd) {
+	case RFCOMMCREATEDEV:
+		return rfcomm_create_dev(sk, arg);
+
+	case RFCOMMRELEASEDEV:
+		return rfcomm_release_dev(arg);
+
+	case RFCOMMGETDEVLIST:
+		return rfcomm_get_dev_list(arg);
+
+	case RFCOMMGETDEVINFO:
+		return rfcomm_get_dev_info(arg);
+	}
+
+	return -EINVAL;
+}
+
+/* ---- DLC callbacks ---- */
+static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb)
+{
+	struct rfcomm_dev *dev = dlc->owner;
+
+	if (!dev) {
+		kfree_skb(skb);
+		return;
+	}
+
+	if (!skb_queue_empty(&dev->pending)) {
+		skb_queue_tail(&dev->pending, skb);
+		return;
+	}
+
+	BT_DBG("dlc %p len %d", dlc, skb->len);
+
+	tty_insert_flip_string(&dev->port, skb->data, skb->len);
+	tty_flip_buffer_push(&dev->port);
+
+	kfree_skb(skb);
+}
+
+static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
+{
+	struct rfcomm_dev *dev = dlc->owner;
+	if (!dev)
+		return;
+
+	BT_DBG("dlc %p dev %p err %d", dlc, dev, err);
+
+	dev->err = err;
+	if (dlc->state == BT_CONNECTED) {
+		rfcomm_reparent_device(dev);
+
+		wake_up_interruptible(&dev->port.open_wait);
+	} else if (dlc->state == BT_CLOSED)
+		tty_port_tty_hangup(&dev->port, false);
+}
+
+static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig)
+{
+	struct rfcomm_dev *dev = dlc->owner;
+	if (!dev)
+		return;
+
+	BT_DBG("dlc %p dev %p v24_sig 0x%02x", dlc, dev, v24_sig);
+
+	if ((dev->modem_status & TIOCM_CD) && !(v24_sig & RFCOMM_V24_DV))
+		tty_port_tty_hangup(&dev->port, true);
+
+	dev->modem_status =
+		((v24_sig & RFCOMM_V24_RTC) ? TIOCM_DSR : 0) |
+		((v24_sig & RFCOMM_V24_RTR) ? TIOCM_CTS : 0) |
+		((v24_sig & RFCOMM_V24_IC)  ? TIOCM_RI : 0) |
+		((v24_sig & RFCOMM_V24_DV)  ? TIOCM_CD : 0);
+}
+
+/* ---- TTY functions ---- */
+static void rfcomm_tty_copy_pending(struct rfcomm_dev *dev)
+{
+	struct sk_buff *skb;
+	int inserted = 0;
+
+	BT_DBG("dev %p", dev);
+
+	rfcomm_dlc_lock(dev->dlc);
+
+	while ((skb = skb_dequeue(&dev->pending))) {
+		inserted += tty_insert_flip_string(&dev->port, skb->data,
+				skb->len);
+		kfree_skb(skb);
+	}
+
+	rfcomm_dlc_unlock(dev->dlc);
+
+	if (inserted > 0)
+		tty_flip_buffer_push(&dev->port);
+}
+
+/* do the reverse of install, clearing the tty fields and releasing the
+ * reference to tty_port
+ */
+static void rfcomm_tty_cleanup(struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+
+	clear_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
+
+	rfcomm_dlc_lock(dev->dlc);
+	tty->driver_data = NULL;
+	rfcomm_dlc_unlock(dev->dlc);
+
+	/*
+	 * purge the dlc->tx_queue to avoid circular dependencies
+	 * between dev and dlc
+	 */
+	skb_queue_purge(&dev->dlc->tx_queue);
+
+	tty_port_put(&dev->port);
+}
+
+/* we acquire the tty_port reference since it's here the tty is first used
+ * by setting the termios. We also populate the driver_data field and install
+ * the tty port
+ */
+static int rfcomm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev;
+	struct rfcomm_dlc *dlc;
+	int err;
+
+	dev = rfcomm_dev_get(tty->index);
+	if (!dev)
+		return -ENODEV;
+
+	dlc = dev->dlc;
+
+	/* Attach TTY and open DLC */
+	rfcomm_dlc_lock(dlc);
+	tty->driver_data = dev;
+	rfcomm_dlc_unlock(dlc);
+	set_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
+
+	/* install the tty_port */
+	err = tty_port_install(&dev->port, driver, tty);
+	if (err) {
+		rfcomm_tty_cleanup(tty);
+		return err;
+	}
+
+	/* take over the tty_port reference if the port was created with the
+	 * flag RFCOMM_RELEASE_ONHUP. This will force the release of the port
+	 * when the last process closes the tty. The behaviour is expected by
+	 * userspace.
+	 */
+	if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) {
+		set_bit(RFCOMM_TTY_OWNED, &dev->status);
+		tty_port_put(&dev->port);
+	}
+
+	return 0;
+}
+
+static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+	int err;
+
+	BT_DBG("tty %p id %d", tty, tty->index);
+
+	BT_DBG("dev %p dst %pMR channel %d opened %d", dev, &dev->dst,
+	       dev->channel, dev->port.count);
+
+	err = tty_port_open(&dev->port, tty, filp);
+	if (err)
+		return err;
+
+	/*
+	 * FIXME: rfcomm should use proper flow control for
+	 * received data. This hack will be unnecessary and can
+	 * be removed when that's implemented
+	 */
+	rfcomm_tty_copy_pending(dev);
+
+	rfcomm_dlc_unthrottle(dev->dlc);
+
+	return 0;
+}
+
+static void rfcomm_tty_close(struct tty_struct *tty, struct file *filp)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+
+	BT_DBG("tty %p dev %p dlc %p opened %d", tty, dev, dev->dlc,
+						dev->port.count);
+
+	tty_port_close(&dev->port, tty, filp);
+}
+
+static ssize_t rfcomm_tty_write(struct tty_struct *tty, const u8 *buf,
+				size_t count)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+	struct rfcomm_dlc *dlc = dev->dlc;
+	struct sk_buff *skb;
+	size_t sent = 0, size;
+
+	BT_DBG("tty %p count %zu", tty, count);
+
+	while (count) {
+		size = min_t(size_t, count, dlc->mtu);
+
+		skb = rfcomm_wmalloc(dev, size + RFCOMM_SKB_RESERVE, GFP_ATOMIC);
+		if (!skb)
+			break;
+
+		skb_reserve(skb, RFCOMM_SKB_HEAD_RESERVE);
+
+		skb_put_data(skb, buf + sent, size);
+
+		rfcomm_dlc_send_noerror(dlc, skb);
+
+		sent  += size;
+		count -= size;
+	}
+
+	return sent;
+}
+
+static unsigned int rfcomm_tty_write_room(struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+	int room = 0;
+
+	if (dev && dev->dlc)
+		room = rfcomm_room(dev);
+
+	BT_DBG("tty %p room %d", tty, room);
+
+	return room;
+}
+
+static int rfcomm_tty_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
+{
+	BT_DBG("tty %p cmd 0x%02x", tty, cmd);
+
+	switch (cmd) {
+	case TCGETS:
+		BT_DBG("TCGETS is not supported");
+		return -ENOIOCTLCMD;
+
+	case TCSETS:
+		BT_DBG("TCSETS is not supported");
+		return -ENOIOCTLCMD;
+
+	case TIOCMIWAIT:
+		BT_DBG("TIOCMIWAIT");
+		break;
+
+	case TIOCSERGETLSR:
+		BT_ERR("TIOCSERGETLSR is not supported");
+		return -ENOIOCTLCMD;
+
+	case TIOCSERCONFIG:
+		BT_ERR("TIOCSERCONFIG is not supported");
+		return -ENOIOCTLCMD;
+
+	default:
+		return -ENOIOCTLCMD;	/* ioctls which we must ignore */
+
+	}
+
+	return -ENOIOCTLCMD;
+}
+
+static void rfcomm_tty_set_termios(struct tty_struct *tty,
+				   const struct ktermios *old)
+{
+	struct ktermios *new = &tty->termios;
+	int old_baud_rate = tty_termios_baud_rate(old);
+	int new_baud_rate = tty_termios_baud_rate(new);
+
+	u8 baud, data_bits, stop_bits, parity, x_on, x_off;
+	u16 changes = 0;
+
+	struct rfcomm_dev *dev = tty->driver_data;
+
+	BT_DBG("tty %p termios %p", tty, old);
+
+	if (!dev || !dev->dlc)
+		return;
+
+	/* Handle turning off CRTSCTS */
+	if ((old->c_cflag & CRTSCTS) && !(new->c_cflag & CRTSCTS))
+		BT_DBG("Turning off CRTSCTS unsupported");
+
+	/* Parity on/off and when on, odd/even */
+	if (((old->c_cflag & PARENB) != (new->c_cflag & PARENB)) ||
+			((old->c_cflag & PARODD) != (new->c_cflag & PARODD))) {
+		changes |= RFCOMM_RPN_PM_PARITY;
+		BT_DBG("Parity change detected.");
+	}
+
+	/* Mark and space parity are not supported! */
+	if (new->c_cflag & PARENB) {
+		if (new->c_cflag & PARODD) {
+			BT_DBG("Parity is ODD");
+			parity = RFCOMM_RPN_PARITY_ODD;
+		} else {
+			BT_DBG("Parity is EVEN");
+			parity = RFCOMM_RPN_PARITY_EVEN;
+		}
+	} else {
+		BT_DBG("Parity is OFF");
+		parity = RFCOMM_RPN_PARITY_NONE;
+	}
+
+	/* Setting the x_on / x_off characters */
+	if (old->c_cc[VSTOP] != new->c_cc[VSTOP]) {
+		BT_DBG("XOFF custom");
+		x_on = new->c_cc[VSTOP];
+		changes |= RFCOMM_RPN_PM_XON;
+	} else {
+		BT_DBG("XOFF default");
+		x_on = RFCOMM_RPN_XON_CHAR;
+	}
+
+	if (old->c_cc[VSTART] != new->c_cc[VSTART]) {
+		BT_DBG("XON custom");
+		x_off = new->c_cc[VSTART];
+		changes |= RFCOMM_RPN_PM_XOFF;
+	} else {
+		BT_DBG("XON default");
+		x_off = RFCOMM_RPN_XOFF_CHAR;
+	}
+
+	/* Handle setting of stop bits */
+	if ((old->c_cflag & CSTOPB) != (new->c_cflag & CSTOPB))
+		changes |= RFCOMM_RPN_PM_STOP;
+
+	/* POSIX does not support 1.5 stop bits and RFCOMM does not
+	 * support 2 stop bits. So a request for 2 stop bits gets
+	 * translated to 1.5 stop bits */
+	if (new->c_cflag & CSTOPB)
+		stop_bits = RFCOMM_RPN_STOP_15;
+	else
+		stop_bits = RFCOMM_RPN_STOP_1;
+
+	/* Handle number of data bits [5-8] */
+	if ((old->c_cflag & CSIZE) != (new->c_cflag & CSIZE))
+		changes |= RFCOMM_RPN_PM_DATA;
+
+	switch (new->c_cflag & CSIZE) {
+	case CS5:
+		data_bits = RFCOMM_RPN_DATA_5;
+		break;
+	case CS6:
+		data_bits = RFCOMM_RPN_DATA_6;
+		break;
+	case CS7:
+		data_bits = RFCOMM_RPN_DATA_7;
+		break;
+	case CS8:
+		data_bits = RFCOMM_RPN_DATA_8;
+		break;
+	default:
+		data_bits = RFCOMM_RPN_DATA_8;
+		break;
+	}
+
+	/* Handle baudrate settings */
+	if (old_baud_rate != new_baud_rate)
+		changes |= RFCOMM_RPN_PM_BITRATE;
+
+	switch (new_baud_rate) {
+	case 2400:
+		baud = RFCOMM_RPN_BR_2400;
+		break;
+	case 4800:
+		baud = RFCOMM_RPN_BR_4800;
+		break;
+	case 7200:
+		baud = RFCOMM_RPN_BR_7200;
+		break;
+	case 9600:
+		baud = RFCOMM_RPN_BR_9600;
+		break;
+	case 19200:
+		baud = RFCOMM_RPN_BR_19200;
+		break;
+	case 38400:
+		baud = RFCOMM_RPN_BR_38400;
+		break;
+	case 57600:
+		baud = RFCOMM_RPN_BR_57600;
+		break;
+	case 115200:
+		baud = RFCOMM_RPN_BR_115200;
+		break;
+	case 230400:
+		baud = RFCOMM_RPN_BR_230400;
+		break;
+	default:
+		/* 9600 is standard according to the RFCOMM specification */
+		baud = RFCOMM_RPN_BR_9600;
+		break;
+
+	}
+
+	if (changes)
+		rfcomm_dlc_send_rpn(dev->dlc, baud, data_bits, stop_bits, parity,
+				    RFCOMM_RPN_FLOW_NONE, x_on, x_off, changes);
+}
+
+static void rfcomm_tty_throttle(struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+
+	BT_DBG("tty %p dev %p", tty, dev);
+
+	rfcomm_dlc_throttle(dev->dlc);
+}
+
+static void rfcomm_tty_unthrottle(struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+
+	BT_DBG("tty %p dev %p", tty, dev);
+
+	rfcomm_dlc_unthrottle(dev->dlc);
+}
+
+static unsigned int rfcomm_tty_chars_in_buffer(struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+
+	BT_DBG("tty %p dev %p", tty, dev);
+
+	if (!dev || !dev->dlc)
+		return 0;
+
+	if (!skb_queue_empty(&dev->dlc->tx_queue))
+		return dev->dlc->mtu;
+
+	return 0;
+}
+
+static void rfcomm_tty_flush_buffer(struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+
+	BT_DBG("tty %p dev %p", tty, dev);
+
+	if (!dev || !dev->dlc)
+		return;
+
+	skb_queue_purge(&dev->dlc->tx_queue);
+	tty_wakeup(tty);
+}
+
+static void rfcomm_tty_send_xchar(struct tty_struct *tty, u8 ch)
+{
+	BT_DBG("tty %p ch %c", tty, ch);
+}
+
+static void rfcomm_tty_wait_until_sent(struct tty_struct *tty, int timeout)
+{
+	BT_DBG("tty %p timeout %d", tty, timeout);
+}
+
+static void rfcomm_tty_hangup(struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+
+	BT_DBG("tty %p dev %p", tty, dev);
+
+	tty_port_hangup(&dev->port);
+}
+
+static int rfcomm_tty_tiocmget(struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+	struct rfcomm_dlc *dlc = dev->dlc;
+	u8 v24_sig;
+
+	BT_DBG("tty %p dev %p", tty, dev);
+
+	rfcomm_dlc_get_modem_status(dlc, &v24_sig);
+
+	return (v24_sig & (TIOCM_DTR | TIOCM_RTS)) | dev->modem_status;
+}
+
+static int rfcomm_tty_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+	struct rfcomm_dlc *dlc = dev->dlc;
+	u8 v24_sig;
+
+	BT_DBG("tty %p dev %p set 0x%02x clear 0x%02x", tty, dev, set, clear);
+
+	rfcomm_dlc_get_modem_status(dlc, &v24_sig);
+
+	if (set & TIOCM_DTR)
+		v24_sig |= RFCOMM_V24_RTC;
+	if (set & TIOCM_RTS)
+		v24_sig |= RFCOMM_V24_RTR;
+
+	if (clear & TIOCM_DTR)
+		v24_sig &= ~RFCOMM_V24_RTC;
+	if (clear & TIOCM_RTS)
+		v24_sig &= ~RFCOMM_V24_RTR;
+
+	rfcomm_dlc_set_modem_status(dlc, v24_sig);
+
+	return 0;
+}
+
+/* ---- TTY structure ---- */
+
+static const struct tty_operations rfcomm_ops = {
+	.open			= rfcomm_tty_open,
+	.close			= rfcomm_tty_close,
+	.write			= rfcomm_tty_write,
+	.write_room		= rfcomm_tty_write_room,
+	.chars_in_buffer	= rfcomm_tty_chars_in_buffer,
+	.flush_buffer		= rfcomm_tty_flush_buffer,
+	.ioctl			= rfcomm_tty_ioctl,
+	.throttle		= rfcomm_tty_throttle,
+	.unthrottle		= rfcomm_tty_unthrottle,
+	.set_termios		= rfcomm_tty_set_termios,
+	.send_xchar		= rfcomm_tty_send_xchar,
+	.hangup			= rfcomm_tty_hangup,
+	.wait_until_sent	= rfcomm_tty_wait_until_sent,
+	.tiocmget		= rfcomm_tty_tiocmget,
+	.tiocmset		= rfcomm_tty_tiocmset,
+	.install                = rfcomm_tty_install,
+	.cleanup                = rfcomm_tty_cleanup,
+};
+
+int __init rfcomm_init_ttys(void)
+{
+	int error;
+
+	rfcomm_tty_driver = tty_alloc_driver(RFCOMM_TTY_PORTS,
+			TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV);
+	if (IS_ERR(rfcomm_tty_driver))
+		return PTR_ERR(rfcomm_tty_driver);
+
+	rfcomm_tty_driver->driver_name	= "rfcomm";
+	rfcomm_tty_driver->name		= "rfcomm";
+	rfcomm_tty_driver->major	= RFCOMM_TTY_MAJOR;
+	rfcomm_tty_driver->minor_start	= RFCOMM_TTY_MINOR;
+	rfcomm_tty_driver->type		= TTY_DRIVER_TYPE_SERIAL;
+	rfcomm_tty_driver->subtype	= SERIAL_TYPE_NORMAL;
+	rfcomm_tty_driver->init_termios	= tty_std_termios;
+	rfcomm_tty_driver->init_termios.c_cflag	= B9600 | CS8 | CREAD | HUPCL;
+	rfcomm_tty_driver->init_termios.c_lflag &= ~ICANON;
+	tty_set_operations(rfcomm_tty_driver, &rfcomm_ops);
+
+	error = tty_register_driver(rfcomm_tty_driver);
+	if (error) {
+		BT_ERR("Can't register RFCOMM TTY driver");
+		tty_driver_kref_put(rfcomm_tty_driver);
+		return error;
+	}
+
+	BT_INFO("RFCOMM TTY layer initialized");
+
+	return 0;
+}
+
+void rfcomm_cleanup_ttys(void)
+{
+	tty_unregister_driver(rfcomm_tty_driver);
+	tty_driver_kref_put(rfcomm_tty_driver);
+}