Bluetooth: Add BT_POWER L2CAP socket option.

Add BT_POWER socket option used to control the power characteristics of the underlying ACL link. When the remote end has put the link in sniff mode and the host stack wants to send data we need need to explicitly exit sniff mode to work well with certain devices (For example, A2DP on Plantronics Voyager 855). However, this causes problems with HID devices. Hence, moving into active mode when sending data, irrespective of who set the sniff mode has been made as a socket option. By default, we will move into active mode. HID devices can set the L2CAP socket option to prevent this from happening. Currently, this has been implemented for L2CAP sockets. This has been tested with incoming and outgoing L2CAP sockets for HID and A2DP. Based on discussions on linux-bluetooth and patches submitted by Andrei Emeltchenko. Signed-off-by: Jaikumar Ganesh <jaikumar@google.com> Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

Bluetooth: Add BT_POWER L2CAP socket option.
Add BT_POWER socket option used to control the power characteristics of the underlying ACL link. When the remote end has put the link in sniff mode and the host stack wants to send data we need need to explicitly exit sniff mode to work well with certain devices (For example, A2DP on Plantronics Voyager 855). However, this causes problems with HID devices. Hence, moving into active mode when sending data, irrespective of who set the sniff mode has been made as a socket option. By default, we will move into active mode. HID devices can set the L2CAP socket option to prevent this from happening. Currently, this has been implemented for L2CAP sockets. This has been tested with incoming and outgoing L2CAP sockets for HID and A2DP. Based on discussions on linux-bluetooth and patches submitted by Andrei Emeltchenko. Signed-off-by: Jaikumar Ganesh <jaikumar@google.com> Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Jaikumar Ganesh · Gustavo F. Padovan
1 parent 96d97a673d
Showing 7 changed files with 59 additions and 6 deletions Side-by-side Diff
include/net/bluetooth/bluetooth.h
include/net/bluetooth/hci_core.h
include/net/bluetooth/l2cap.h
net/bluetooth/hci_conn.c
net/bluetooth/hci_core.c
net/bluetooth/l2cap_core.c
net/bluetooth/l2cap_sock.c
@@ -69,6 +69,13 @@
 #define BT_FLUSHABLE_OFF	0
 #define BT_FLUSHABLE_ON		1
  
+#define BT_POWER	9
+struct bt_power {
+	__u8 force_active;
+};
+#define BT_POWER_FORCE_ACTIVE_OFF 0
+#define BT_POWER_FORCE_ACTIVE_ON  1
+
 #define BT_INFO(fmt, arg...) printk(KERN_INFO "Bluetooth: " fmt "\n" , ## arg)
 #define BT_ERR(fmt, arg...)  printk(KERN_ERR "%s: " fmt "\n" , __func__ , ## arg)
 #define BT_DBG(fmt, arg...)  pr_debug("%s: " fmt "\n" , __func__ , ## arg)
@@ -150,6 +157,7 @@
 	__u8 retries;
 	__u8 sar;
 	unsigned short channel;
+	__u8 force_active;
 };
 #define bt_cb(skb) ((struct bt_skb_cb *)((skb)->cb))
  
@@ -438,7 +438,7 @@
 int hci_conn_change_link_key(struct hci_conn *conn);
 int hci_conn_switch_role(struct hci_conn *conn, __u8 role);
  
-void hci_conn_enter_active_mode(struct hci_conn *conn);
+void hci_conn_enter_active_mode(struct hci_conn *conn, __u8 force_active);
 void hci_conn_enter_sniff_mode(struct hci_conn *conn);
  
 void hci_conn_hold_device(struct hci_conn *conn);
@@ -303,6 +303,7 @@
 	__u8		role_switch;
 	__u8		force_reliable;
 	__u8		flushable;
+	__u8		force_active;
  
 	__u8		ident;
  
@@ -507,7 +507,7 @@
 	if (acl->state == BT_CONNECTED &&
 			(sco->state == BT_OPEN || sco->state == BT_CLOSED)) {
 		acl->power_save = 1;
-		hci_conn_enter_active_mode(acl);
+		hci_conn_enter_active_mode(acl, BT_POWER_FORCE_ACTIVE_ON);
  
 		if (test_bit(HCI_CONN_MODE_CHANGE_PEND, &acl->pend)) {
 			/* defer SCO setup until mode change completed */
@@ -688,7 +688,7 @@
 EXPORT_SYMBOL(hci_conn_switch_role);
  
 /* Enter active mode */
-void hci_conn_enter_active_mode(struct hci_conn *conn)
+void hci_conn_enter_active_mode(struct hci_conn *conn, __u8 force_active)
 {
 	struct hci_dev *hdev = conn->hdev;
  
@@ -697,7 +697,10 @@
 	if (test_bit(HCI_RAW, &hdev->flags))
 		return;
  
-	if (conn->mode != HCI_CM_SNIFF || !conn->power_save)
+	if (conn->mode != HCI_CM_SNIFF)
+		goto timer;
+
+	if (!conn->power_save && !force_active)
 		goto timer;
  
 	if (!test_and_set_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend)) {
@@ -1969,7 +1969,7 @@
 		while (quote-- && (skb = skb_dequeue(&conn->data_q))) {
 			BT_DBG("skb %p len %d", skb, skb->len);
  
-			hci_conn_enter_active_mode(conn);
+			hci_conn_enter_active_mode(conn, bt_cb(skb)->force_active);
  
 			hci_send_frame(skb);
 			hdev->acl_last_tx = jiffies;
@@ -2108,7 +2108,7 @@
 	if (conn) {
 		register struct hci_proto *hp;
  
-		hci_conn_enter_active_mode(conn);
+		hci_conn_enter_active_mode(conn, bt_cb(skb)->force_active);
  
 		/* Send to upper protocol */
 		hp = hci_proto[HCI_PROTO_L2CAP];
@@ -537,6 +537,8 @@
 	else
 		flags = ACL_START;
  
+	bt_cb(skb)->force_active = BT_POWER_FORCE_ACTIVE_ON;
+
 	hci_send_acl(conn->hcon, skb, flags);
 }
  
@@ -590,6 +592,8 @@
 	else
 		flags = ACL_START;
  
+	bt_cb(skb)->force_active = chan->force_active;
+
 	hci_send_acl(chan->conn->hcon, skb, flags);
 }
  
@@ -1215,6 +1219,7 @@
 	else
 		flags = ACL_START;
  
+	bt_cb(skb)->force_active = chan->force_active;
 	hci_send_acl(hcon, skb, flags);
 }
  
@@ -390,6 +390,7 @@
 	struct sock *sk = sock->sk;
 	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
 	struct bt_security sec;
+	struct bt_power pwr;
 	int len, err = 0;
  
 	BT_DBG("sk %p", sk);
@@ -438,6 +439,21 @@
  
 		break;
  
+	case BT_POWER:
+		if (sk->sk_type != SOCK_SEQPACKET && sk->sk_type != SOCK_STREAM
+				&& sk->sk_type != SOCK_RAW) {
+			err = -EINVAL;
+			break;
+		}
+
+		pwr.force_active = chan->force_active;
+
+		len = min_t(unsigned int, len, sizeof(pwr));
+		if (copy_to_user(optval, (char *) &pwr, len))
+			err = -EFAULT;
+
+		break;
+
 	default:
 		err = -ENOPROTOOPT;
 		break;
@@ -538,6 +554,7 @@
 	struct sock *sk = sock->sk;
 	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
 	struct bt_security sec;
+	struct bt_power pwr;
 	int len, err = 0;
 	u32 opt;
  
@@ -614,6 +631,23 @@
 		chan->flushable = opt;
 		break;
  
+	case BT_POWER:
+		if (chan->chan_type != L2CAP_CHAN_CONN_ORIENTED &&
+					chan->chan_type != L2CAP_CHAN_RAW) {
+			err = -EINVAL;
+			break;
+		}
+
+		pwr.force_active = BT_POWER_FORCE_ACTIVE_ON;
+
+		len = min_t(unsigned int, sizeof(pwr), optlen);
+		if (copy_from_user((char *) &pwr, optval, len)) {
+			err = -EFAULT;
+			break;
+		}
+		chan->force_active = pwr.force_active;
+		break;
+
 	default:
 		err = -ENOPROTOOPT;
 		break;
@@ -771,6 +805,7 @@
 		chan->role_switch = pchan->role_switch;
 		chan->force_reliable = pchan->force_reliable;
 		chan->flushable = pchan->flushable;
+		chan->force_active = pchan->force_active;
 	} else {
  
 		switch (sk->sk_type) {
@@ -801,6 +836,7 @@
 		chan->role_switch = 0;
 		chan->force_reliable = 0;
 		chan->flushable = BT_FLUSHABLE_OFF;
+		chan->force_active = BT_POWER_FORCE_ACTIVE_ON;
 	}
  
 	/* Default config options */
...	...	@@ -69,6 +69,13 @@
69	69	#define BT_FLUSHABLE_OFF 0
70	70	#define BT_FLUSHABLE_ON 1
71	71
	72	+#define BT_POWER 9
	73	+struct bt_power {
	74	+ __u8 force_active;
	75	+};
	76	+#define BT_POWER_FORCE_ACTIVE_OFF 0
	77	+#define BT_POWER_FORCE_ACTIVE_ON 1
	78	+
72	79	#define BT_INFO(fmt, arg...) printk(KERN_INFO "Bluetooth: " fmt "\n" , ## arg)
73	80	#define BT_ERR(fmt, arg...) printk(KERN_ERR "%s: " fmt "\n" , __func__ , ## arg)
74	81	#define BT_DBG(fmt, arg...) pr_debug("%s: " fmt "\n" , __func__ , ## arg)
...	...	@@ -150,6 +157,7 @@
150	157	__u8 retries;
151	158	__u8 sar;
152	159	unsigned short channel;
	160	+ __u8 force_active;
153	161	};
154	162	#define bt_cb(skb) ((struct bt_skb_cb *)((skb)->cb))
155	163
...	...	@@ -438,7 +438,7 @@
438	438	int hci_conn_change_link_key(struct hci_conn *conn);
439	439	int hci_conn_switch_role(struct hci_conn *conn, __u8 role);
440	440
441		-void hci_conn_enter_active_mode(struct hci_conn *conn);
	441	+void hci_conn_enter_active_mode(struct hci_conn *conn, __u8 force_active);
442	442	void hci_conn_enter_sniff_mode(struct hci_conn *conn);
443	443
444	444	void hci_conn_hold_device(struct hci_conn *conn);
...	...	@@ -303,6 +303,7 @@
303	303	__u8 role_switch;
304	304	__u8 force_reliable;
305	305	__u8 flushable;
	306	+ __u8 force_active;
306	307
307	308	__u8 ident;
308	309
...	...	@@ -507,7 +507,7 @@
507	507	if (acl->state == BT_CONNECTED &&
508	508	(sco->state == BT_OPEN \|\| sco->state == BT_CLOSED)) {
509	509	acl->power_save = 1;
510		- hci_conn_enter_active_mode(acl);
	510	+ hci_conn_enter_active_mode(acl, BT_POWER_FORCE_ACTIVE_ON);
511	511
512	512	if (test_bit(HCI_CONN_MODE_CHANGE_PEND, &acl->pend)) {
513	513	/* defer SCO setup until mode change completed */
...	...	@@ -688,7 +688,7 @@
688	688	EXPORT_SYMBOL(hci_conn_switch_role);
689	689
690	690	/* Enter active mode */
691		-void hci_conn_enter_active_mode(struct hci_conn *conn)
	691	+void hci_conn_enter_active_mode(struct hci_conn *conn, __u8 force_active)
692	692	{
693	693	struct hci_dev *hdev = conn->hdev;
694	694
...	...	@@ -697,7 +697,10 @@
697	697	if (test_bit(HCI_RAW, &hdev->flags))
698	698	return;
699	699
700		- if (conn->mode != HCI_CM_SNIFF \|\| !conn->power_save)
	700	+ if (conn->mode != HCI_CM_SNIFF)
	701	+ goto timer;
	702	+
	703	+ if (!conn->power_save && !force_active)
701	704	goto timer;
702	705
703	706	if (!test_and_set_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend)) {
...	...	@@ -1969,7 +1969,7 @@
1969	1969	while (quote-- && (skb = skb_dequeue(&conn->data_q))) {
1970	1970	BT_DBG("skb %p len %d", skb, skb->len);
1971	1971
1972		- hci_conn_enter_active_mode(conn);
	1972	+ hci_conn_enter_active_mode(conn, bt_cb(skb)->force_active);
1973	1973
1974	1974	hci_send_frame(skb);
1975	1975	hdev->acl_last_tx = jiffies;
...	...	@@ -2108,7 +2108,7 @@
2108	2108	if (conn) {
2109	2109	register struct hci_proto *hp;
2110	2110
2111		- hci_conn_enter_active_mode(conn);
	2111	+ hci_conn_enter_active_mode(conn, bt_cb(skb)->force_active);
2112	2112
2113	2113	/* Send to upper protocol */
2114	2114	hp = hci_proto[HCI_PROTO_L2CAP];
...	...	@@ -537,6 +537,8 @@
537	537	else
538	538	flags = ACL_START;
539	539
	540	+ bt_cb(skb)->force_active = BT_POWER_FORCE_ACTIVE_ON;
	541	+
540	542	hci_send_acl(conn->hcon, skb, flags);
541	543	}
542	544
...	...	@@ -590,6 +592,8 @@
590	592	else
591	593	flags = ACL_START;
592	594
	595	+ bt_cb(skb)->force_active = chan->force_active;
	596	+
593	597	hci_send_acl(chan->conn->hcon, skb, flags);
594	598	}
595	599
...	...	@@ -1215,6 +1219,7 @@
1215	1219	else
1216	1220	flags = ACL_START;
1217	1221
	1222	+ bt_cb(skb)->force_active = chan->force_active;
1218	1223	hci_send_acl(hcon, skb, flags);
1219	1224	}
1220	1225
...	...	@@ -390,6 +390,7 @@
390	390	struct sock *sk = sock->sk;
391	391	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
392	392	struct bt_security sec;
	393	+ struct bt_power pwr;
393	394	int len, err = 0;
394	395
395	396	BT_DBG("sk %p", sk);
...	...	@@ -438,6 +439,21 @@
438	439
439	440	break;
440	441
	442	+ case BT_POWER:
	443	+ if (sk->sk_type != SOCK_SEQPACKET && sk->sk_type != SOCK_STREAM
	444	+ && sk->sk_type != SOCK_RAW) {
	445	+ err = -EINVAL;
	446	+ break;
	447	+ }
	448	+
	449	+ pwr.force_active = chan->force_active;
	450	+
	451	+ len = min_t(unsigned int, len, sizeof(pwr));
	452	+ if (copy_to_user(optval, (char *) &pwr, len))
	453	+ err = -EFAULT;
	454	+
	455	+ break;
	456	+
441	457	default:
442	458	err = -ENOPROTOOPT;
443	459	break;
...	...	@@ -538,6 +554,7 @@
538	554	struct sock *sk = sock->sk;
539	555	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
540	556	struct bt_security sec;
	557	+ struct bt_power pwr;
541	558	int len, err = 0;
542	559	u32 opt;
543	560
...	...	@@ -614,6 +631,23 @@
614	631	chan->flushable = opt;
615	632	break;
616	633
	634	+ case BT_POWER:
	635	+ if (chan->chan_type != L2CAP_CHAN_CONN_ORIENTED &&
	636	+ chan->chan_type != L2CAP_CHAN_RAW) {
	637	+ err = -EINVAL;
	638	+ break;
	639	+ }
	640	+
	641	+ pwr.force_active = BT_POWER_FORCE_ACTIVE_ON;
	642	+
	643	+ len = min_t(unsigned int, sizeof(pwr), optlen);
	644	+ if (copy_from_user((char *) &pwr, optval, len)) {
	645	+ err = -EFAULT;
	646	+ break;
	647	+ }
	648	+ chan->force_active = pwr.force_active;
	649	+ break;
	650	+
617	651	default:
618	652	err = -ENOPROTOOPT;
619	653	break;
...	...	@@ -771,6 +805,7 @@
771	805	chan->role_switch = pchan->role_switch;
772	806	chan->force_reliable = pchan->force_reliable;
773	807	chan->flushable = pchan->flushable;
	808	+ chan->force_active = pchan->force_active;
774	809	} else {
775	810
776	811	switch (sk->sk_type) {
...	...	@@ -801,6 +836,7 @@
801	836	chan->role_switch = 0;
802	837	chan->force_reliable = 0;
803	838	chan->flushable = BT_FLUSHABLE_OFF;
	839	+ chan->force_active = BT_POWER_FORCE_ACTIVE_ON;
804	840	}
805	841
806	842	/* Default config options */