Bluetooth: Add BTPROTO_ISO socket type

This introduces a new socket type BTPROTO_ISO which can be enabled with
use of ISO Socket experiemental UUID, it can used to initiate/accept
connections and transfer packets between userspace and kernel similarly
to how BTPROTO_SCO works:

Central -> uses connect with address set to destination bdaddr:
> tools/isotest -s 00:AA:01:00:00:00

Peripheral -> uses listen:
> tools/isotest -d

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

include/net/bluetooth/bluetooth.h

@@ -590,6 +590,27 @@ static inline void sco_exit(void)
 }
 #endif
 
+#if IS_ENABLED(CONFIG_BT_LE)
+int iso_init(void);
+int iso_exit(void);
+bool iso_enabled(void);
+#else
+static inline int iso_init(void)
+{
+	return 0;
+}
+
+static inline int iso_exit(void)
+{
+	return 0;
+}
+
+static inline bool iso_enabled(void)
+{
+	return false;
+}
+#endif
+
 int mgmt_init(void);
 void mgmt_exit(void);
 

include/net/bluetooth/hci_core.h

@@ -843,6 +843,21 @@ static inline void sco_recv_scodata(struct hci_conn *hcon, struct sk_buff *skb)
 }
 #endif
 
+#if IS_ENABLED(CONFIG_BT_LE)
+int iso_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags);
+void iso_recv(struct hci_conn *hcon, struct sk_buff *skb, u16 flags);
+#else
+static inline int iso_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr,
+				  __u8 *flags)
+{
+	return 0;
+}
+static inline void iso_recv(struct hci_conn *hcon, struct sk_buff *skb,
+			    u16 flags)
+{
+}
+#endif
+
 /* ----- Inquiry cache ----- */
 #define INQUIRY_CACHE_AGE_MAX   (HZ*30)   /* 30 seconds */
 #define INQUIRY_ENTRY_AGE_MAX   (HZ*60)   /* 60 seconds */
@@ -1640,8 +1655,7 @@ static inline int hci_proto_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr,
 		return sco_connect_ind(hdev, bdaddr, flags);
 
 	case ISO_LINK:
-		/* TODO: Handle connection indication */
-		return -EINVAL;
+		return iso_connect_ind(hdev, bdaddr, flags);
 
 	default:
 		BT_ERR("unknown link type %d", type);

include/net/bluetooth/iso.h

@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * BlueZ - Bluetooth protocol stack for Linux
+ *
+ * Copyright (C) 2022 Intel Corporation
+ */
+
+#ifndef __ISO_H
+#define __ISO_H
+
+/* ISO defaults */
+#define ISO_DEFAULT_MTU		251
+
+/* ISO socket address */
+struct sockaddr_iso {
+	sa_family_t	iso_family;
+	bdaddr_t	iso_bdaddr;
+	__u8		iso_bdaddr_type;
+};
+
+#endif /* __ISO_H */

net/bluetooth/Makefile

@@ -18,6 +18,7 @@ bluetooth-y := af_bluetooth.o hci_core.o hci_conn.o hci_event.o mgmt.o \
 	eir.o hci_sync.o
 
 bluetooth-$(CONFIG_BT_BREDR) += sco.o
+bluetooth-$(CONFIG_BT_LE) += iso.o
 bluetooth-$(CONFIG_BT_HS) += a2mp.o amp.o
 bluetooth-$(CONFIG_BT_LEDS) += leds.o
 bluetooth-$(CONFIG_BT_MSFTEXT) += msft.o

net/bluetooth/af_bluetooth.c

@@ -38,7 +38,7 @@
 #include "selftest.h"
 
 /* Bluetooth sockets */
-#define BT_MAX_PROTO	8
+#define BT_MAX_PROTO	(BTPROTO_LAST + 1)
 static const struct net_proto_family *bt_proto[BT_MAX_PROTO];
 static DEFINE_RWLOCK(bt_proto_lock);
 
@@ -52,6 +52,7 @@ static const char *const bt_key_strings[BT_MAX_PROTO] = {
 	"sk_lock-AF_BLUETOOTH-BTPROTO_CMTP",
 	"sk_lock-AF_BLUETOOTH-BTPROTO_HIDP",
 	"sk_lock-AF_BLUETOOTH-BTPROTO_AVDTP",
+	"sk_lock-AF_BLUETOOTH-BTPROTO_ISO",
 };
 
 static struct lock_class_key bt_slock_key[BT_MAX_PROTO];
@@ -64,6 +65,7 @@ static const char *const bt_slock_key_strings[BT_MAX_PROTO] = {
 	"slock-AF_BLUETOOTH-BTPROTO_CMTP",
 	"slock-AF_BLUETOOTH-BTPROTO_HIDP",
 	"slock-AF_BLUETOOTH-BTPROTO_AVDTP",
+	"slock-AF_BLUETOOTH-BTPROTO_ISO",
 };
 
 void bt_sock_reclassify_lock(struct sock *sk, int proto)

net/bluetooth/hci_core.c

@@ -3822,12 +3822,16 @@ static void hci_isodata_packet(struct hci_dev *hdev, struct sk_buff *skb)
 	conn = hci_conn_hash_lookup_handle(hdev, handle);
 	hci_dev_unlock(hdev);
 
-	/* TODO: Send to upper protocol */
 	if (!conn) {
 		bt_dev_err(hdev, "ISO packet for unknown connection handle %d",
 			   handle);
+		goto drop;
 	}
 
+	/* Send to upper protocol */
+	iso_recv(conn, skb, flags);
+	return;
+
 drop:
 	kfree_skb(skb);
 }