Bluetooth: Add support for sending system notes to monitor channel

The monitor channel can be used to send generic system notes as text
strings for debugging purposes. This adds the system note monitor code
and uses it for including kernel and subsystem version into traces.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index 18a41eae295c..710265c35d16 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -26,6 +26,8 @@
 
 #include <linux/export.h>
 #include <asm/unaligned.h>
+#include <generated/compile.h>
+#include <generated/utsrelease.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -383,6 +385,29 @@ static struct sk_buff *create_monitor_event(struct hci_dev *hdev, int event)
 	return skb;
 }
 
+static void send_monitor_note(struct sock *sk, const char *text)
+{
+	size_t len = strlen(text);
+	struct hci_mon_hdr *hdr;
+	struct sk_buff *skb;
+
+	skb = bt_skb_alloc(len + 1, GFP_ATOMIC);
+	if (!skb)
+		return;
+
+	strcpy(skb_put(skb, len + 1), text);
+
+	__net_timestamp(skb);
+
+	hdr = (void *)skb_push(skb, HCI_MON_HDR_SIZE);
+	hdr->opcode = cpu_to_le16(HCI_MON_SYSTEM_NOTE);
+	hdr->index = cpu_to_le16(HCI_DEV_NONE);
+	hdr->len = cpu_to_le16(skb->len - HCI_MON_HDR_SIZE);
+
+	if (sock_queue_rcv_skb(sk, skb))
+		kfree_skb(skb);
+}
+
 static void send_monitor_replay(struct sock *sk)
 {
 	struct hci_dev *hdev;
@@ -872,6 +897,10 @@ static int hci_sock_bind(struct socket *sock, struct sockaddr *addr,
 		 */
 		hci_sock_set_flag(sk, HCI_SOCK_TRUSTED);
 
+		send_monitor_note(sk, "Linux version " UTS_RELEASE
+				      " (" UTS_MACHINE ")");
+		send_monitor_note(sk, "Bluetooth subsystem version "
+				      BT_SUBSYS_VERSION);
 		send_monitor_replay(sk);
 
 		atomic_inc(&monitor_promisc);