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

+/* 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);
 }

net/bluetooth/mgmt.c

@@ -3985,10 +3985,16 @@ static const u8 rpa_resolution_uuid[16] = {
 	0xea, 0x11, 0x73, 0xc2, 0x48, 0xa1, 0xc0, 0x15,
 };
 
+/* 6fbaf188-05e0-496a-9885-d6ddfdb4e03e */
+static const u8 iso_socket_uuid[16] = {
+	0x3e, 0xe0, 0xb4, 0xfd, 0xdd, 0xd6, 0x85, 0x98,
+	0x6a, 0x49, 0xe0, 0x05, 0x88, 0xf1, 0xba, 0x6f,
+};
+
 static int read_exp_features_info(struct sock *sk, struct hci_dev *hdev,
 				  void *data, u16 data_len)
 {
-	char buf[102];   /* Enough space for 5 features: 2 + 20 * 5 */
+	char buf[122];   /* Enough space for 6 features: 2 + 20 * 6 */
 	struct mgmt_rp_read_exp_features_info *rp = (void *)buf;
 	u16 idx = 0;
 	u32 flags;
@@ -4052,6 +4058,13 @@ static int read_exp_features_info(struct sock *sk, struct hci_dev *hdev,
 		idx++;
 	}
 
+	if (IS_ENABLED(CONFIG_BT_LE)) {
+		flags = iso_enabled() ? BIT(0) : 0;
+		memcpy(rp->features[idx].uuid, iso_socket_uuid, 16);
+		rp->features[idx].flags = cpu_to_le32(flags);
+		idx++;
+	}
+
 	rp->feature_count = cpu_to_le16(idx);
 
 	/* After reading the experimental features information, enable
@@ -4444,6 +4457,57 @@ static int set_le_simultaneous_roles_func(struct sock *sk, struct hci_dev *hdev,
 	return err;
 }
 
+#ifdef CONFIG_BT_LE
+static int set_iso_socket_func(struct sock *sk, struct hci_dev *hdev,
+			       struct mgmt_cp_set_exp_feature *cp, u16 data_len)
+{
+	struct mgmt_rp_set_exp_feature rp;
+	bool val, changed = false;
+	int err;
+
+	/* Command requires to use the non-controller index */
+	if (hdev)
+		return mgmt_cmd_status(sk, hdev->id,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_INVALID_INDEX);
+
+	/* Parameters are limited to a single octet */
+	if (data_len != MGMT_SET_EXP_FEATURE_SIZE + 1)
+		return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_INVALID_PARAMS);
+
+	/* Only boolean on/off is supported */
+	if (cp->param[0] != 0x00 && cp->param[0] != 0x01)
+		return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
+				       MGMT_OP_SET_EXP_FEATURE,
+				       MGMT_STATUS_INVALID_PARAMS);
+
+	val = cp->param[0] ? true : false;
+	if (val)
+		err = iso_init();
+	else
+		err = iso_exit();
+
+	if (!err)
+		changed = true;
+
+	memcpy(rp.uuid, iso_socket_uuid, 16);
+	rp.flags = cpu_to_le32(val ? BIT(0) : 0);
+
+	hci_sock_set_flag(sk, HCI_MGMT_EXP_FEATURE_EVENTS);
+
+	err = mgmt_cmd_complete(sk, MGMT_INDEX_NONE,
+				MGMT_OP_SET_EXP_FEATURE, 0,
+				&rp, sizeof(rp));
+
+	if (changed)
+		exp_feature_changed(hdev, iso_socket_uuid, val, sk);
+
+	return err;
+}
+#endif
+
 static const struct mgmt_exp_feature {
 	const u8 *uuid;
 	int (*set_func)(struct sock *sk, struct hci_dev *hdev,
@@ -4457,6 +4521,9 @@ static const struct mgmt_exp_feature {
 	EXP_FEAT(quality_report_uuid, set_quality_report_func),
 	EXP_FEAT(offload_codecs_uuid, set_offload_codec_func),
 	EXP_FEAT(le_simultaneous_roles_uuid, set_le_simultaneous_roles_func),
+#ifdef CONFIG_BT_LE
+	EXP_FEAT(iso_socket_uuid, set_iso_socket_func),
+#endif
 
 	/* end with a null feature */
 	EXP_FEAT(NULL, NULL)