Hi Gustavo,
On Thu, Dec 23, 2010 at 4:06 AM, Gustavo F. Padovan
<padovan@xxxxxxxxxxxxxx> wrote:
> Hi Andrei,
>
> * Emeltchenko Andrei <Andrei.Emeltchenko.news@xxxxxxxxx> [2010-12-16 16:54:26 +0200]:
>
>> From: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
>>
>> Modification of Nick Pelly <npelly@xxxxxxxxxx> patch.
>>
>> With Bluetooth 2.1 ACL packets can be flushable or non-flushable. This commit
>> makes ACL data packets non-flushable by default on compatible chipsets, and
>> adds the BT_FLUSHABLE socket option to explicitly request flushable ACL
>> data packets for a given L2CAP socket. This is useful for A2DP data which can
>> be safely discarded if it can not be delivered within a short time (while
>> other ACL data should not be discarded).
>>
>> Note that making ACL data flushable has no effect unless the automatic flush
>> timeout for that ACL link is changed from its default of 0 (infinite).
>>
>> Default packet types (for compatible chipsets):
>> Frame 34: 13 bytes on wire (104 bits), 13 bytes captured (104 bits)
>> Bluetooth HCI H4
>> Bluetooth HCI ACL Packet
>> .... 0000 0000 0010 = Connection Handle: 0x0002
>> ..00 .... .... .... = PB Flag: First Non-automatically Flushable Packet (0)
>> 00.. .... .... .... = BC Flag: Point-To-Point (0)
>> Data Total Length: 8
>> Bluetooth L2CAP Packet
>>
>> After setting BT_FLUSHABLE
>> (sock.setsockopt(274 /*SOL_BLUETOOTH*/, 8 /* BT_FLUSHABLE */, 1 /* flush */))
>> Frame 34: 13 bytes on wire (104 bits), 13 bytes captured (104 bits)
>> Bluetooth HCI H4
>> Bluetooth HCI ACL Packet
>> .... 0000 0000 0010 = Connection Handle: 0x0002
>> ..10 .... .... .... = PB Flag: First Automatically Flushable Packet (2)
>> 00.. .... .... .... = BC Flag: Point-To-Point (0)
>> Data Total Length: 8
>> Bluetooth L2CAP Packet
>>
>> Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
>> ---
>> include/net/bluetooth/bluetooth.h | 5 ++++
>> include/net/bluetooth/hci.h | 2 +
>> include/net/bluetooth/hci_core.h | 1 +
>> include/net/bluetooth/l2cap.h | 2 +
>> net/bluetooth/hci_core.c | 6 +++-
>> net/bluetooth/l2cap.c | 48 ++++++++++++++++++++++++++++++++++--
>> 6 files changed, 59 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
>> index 0c5e725..ed7d775 100644
>> --- a/include/net/bluetooth/bluetooth.h
>> +++ b/include/net/bluetooth/bluetooth.h
>> @@ -64,6 +64,11 @@ struct bt_security {
>>
>> #define BT_DEFER_SETUP 7
>>
>> +#define BT_FLUSHABLE 8
>> +
>> +#define BT_FLUSHABLE_OFF 0
>> +#define BT_FLUSHABLE_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)
>> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
>> index 29a7a8c..333d5cb 100644
>> --- a/include/net/bluetooth/hci.h
>> +++ b/include/net/bluetooth/hci.h
>> @@ -150,6 +150,7 @@ enum {
>> #define EDR_ESCO_MASK (ESCO_2EV3 | ESCO_3EV3 | ESCO_2EV5 | ESCO_3EV5)
>>
>> /* ACL flags */
>> +#define ACL_START_NO_FLUSH 0x00
>> #define ACL_CONT 0x01
>> #define ACL_START 0x02
>> #define ACL_ACTIVE_BCAST 0x04
>> @@ -193,6 +194,7 @@ enum {
>> #define LMP_EDR_ESCO_3M 0x40
>> #define LMP_EDR_3S_ESCO 0x80
>>
>> +#define LMP_NO_FLUSH 0x01
>
> Isn't this 0x40? As stated on Core v4.0 (Volume 2, part C, 3.3 Feature Mask
> Definition)
>
>> #define LMP_SIMPLE_PAIR 0x08
>>
>> /* Connection modes */
>> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
>> index 1992fac..9778bc8 100644
>> --- a/include/net/bluetooth/hci_core.h
>> +++ b/include/net/bluetooth/hci_core.h
>> @@ -456,6 +456,7 @@ void hci_conn_del_sysfs(struct hci_conn *conn);
>> #define lmp_sniffsubr_capable(dev) ((dev)->features[5] & LMP_SNIFF_SUBR)
>> #define lmp_esco_capable(dev) ((dev)->features[3] & LMP_ESCO)
>> #define lmp_ssp_capable(dev) ((dev)->features[6] & LMP_SIMPLE_PAIR)
>> +#define lmp_no_flush_capable(dev) ((dev)->features[6] & LMP_NO_FLUSH)
>>
>> /* ----- HCI protocols ----- */
>> struct hci_proto {
>> diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
>> index 7ad25ca..af35711 100644
>> --- a/include/net/bluetooth/l2cap.h
>> +++ b/include/net/bluetooth/l2cap.h
>> @@ -75,6 +75,7 @@ struct l2cap_conninfo {
>> #define L2CAP_LM_TRUSTED 0x0008
>> #define L2CAP_LM_RELIABLE 0x0010
>> #define L2CAP_LM_SECURE 0x0020
>> +#define L2CAP_LM_FLUSHABLE 0x0040
>
> Not using this flag in the code.
>
>>
>> /* L2CAP command codes */
>> #define L2CAP_COMMAND_REJ 0x01
>> @@ -327,6 +328,7 @@ struct l2cap_pinfo {
>> __u8 sec_level;
>> __u8 role_switch;
>> __u8 force_reliable;
>> + __u8 flushable;
>>
>> __u8 conf_req[64];
>> __u8 conf_len;
>> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
>> index 51c61f7..c0d776b 100644
>> --- a/net/bluetooth/hci_core.c
>> +++ b/net/bluetooth/hci_core.c
>> @@ -1380,7 +1380,7 @@ void hci_send_acl(struct hci_conn *conn, struct sk_buff *skb, __u16 flags)
>>
>> skb->dev = (void *) hdev;
>> bt_cb(skb)->pkt_type = HCI_ACLDATA_PKT;
>> - hci_add_acl_hdr(skb, conn->handle, flags | ACL_START);
>> + hci_add_acl_hdr(skb, conn->handle, flags);
>>
>> list = skb_shinfo(skb)->frag_list;
>> if (!list) {
>> @@ -1398,12 +1398,14 @@ void hci_send_acl(struct hci_conn *conn, struct sk_buff *skb, __u16 flags)
>> spin_lock_bh(&conn->data_q.lock);
>>
>> __skb_queue_tail(&conn->data_q, skb);
>
> add an empty line here.
>
>> + flags &= ~ACL_START;
>> + flags |= ACL_CONT;
>> do {
>> skb = list; list = list->next;
>>
>> skb->dev = (void *) hdev;
>> bt_cb(skb)->pkt_type = HCI_ACLDATA_PKT;
>> - hci_add_acl_hdr(skb, conn->handle, flags | ACL_CONT);
>> + hci_add_acl_hdr(skb, conn->handle, flags);
>>
>> BT_DBG("%s frag %p len %d", hdev->name, skb, skb->len);
>>
>> diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
>> index c791fcd..efa60eb 100644
>> --- a/net/bluetooth/l2cap.c
>> +++ b/net/bluetooth/l2cap.c
>> @@ -362,13 +362,19 @@ static inline u8 l2cap_get_ident(struct l2cap_conn *conn)
>> static inline void l2cap_send_cmd(struct l2cap_conn *conn, u8 ident, u8 code, u16 len, void *data)
>> {
>> struct sk_buff *skb = l2cap_build_cmd(conn, code, ident, len, data);
>> + u8 flags;
>>
>> BT_DBG("code 0x%2.2x", code);
>>
>> if (!skb)
>> return;
>>
>> - hci_send_acl(conn->hcon, skb, 0);
>> + if (lmp_no_flush_capable(conn->hcon->hdev))
>> + flags = ACL_START_NO_FLUSH;
>> + else
>> + flags = ACL_START;
>> +
>> + hci_send_acl(conn->hcon, skb, flags);
>> }
>>
>> static inline void l2cap_send_sframe(struct l2cap_pinfo *pi, u16 control)
>> @@ -900,6 +906,7 @@ static void l2cap_sock_init(struct sock *sk, struct sock *parent)
>> pi->sec_level = l2cap_pi(parent)->sec_level;
>> pi->role_switch = l2cap_pi(parent)->role_switch;
>> pi->force_reliable = l2cap_pi(parent)->force_reliable;
>> + pi->flushable = l2cap_pi(parent)->flushable;
>> } else {
>> pi->imtu = L2CAP_DEFAULT_MTU;
>> pi->omtu = 0;
>> @@ -915,6 +922,7 @@ static void l2cap_sock_init(struct sock *sk, struct sock *parent)
>> pi->sec_level = BT_SECURITY_LOW;
>> pi->role_switch = 0;
>> pi->force_reliable = 0;
>> + pi->flushable = BT_FLUSHABLE_OFF;
>
> You need to check for the no_flush feature here, right?
I think at this stage we do not have hci and l2cap connection handlers
added to the socket.
We assign it in l2cap_chan_add later when making connect. Do you think
it makes sense to add the check there?
I am sending the latest patch leaving this unchanged for now.
Regards,
Andrei
>
>> }
>>
>> /* Default config options */
>> @@ -1450,10 +1458,17 @@ static void l2cap_drop_acked_frames(struct sock *sk)
>> static inline void l2cap_do_send(struct sock *sk, struct sk_buff *skb)
>> {
>> struct l2cap_pinfo *pi = l2cap_pi(sk);
>> + struct hci_conn *hcon = pi->conn->hcon;
>> + u16 flags;
>>
>> BT_DBG("sk %p, skb %p len %d", sk, skb, skb->len);
>>
>> - hci_send_acl(pi->conn->hcon, skb, 0);
>> + if (lmp_no_flush_capable(hcon->hdev) && !l2cap_pi(sk)->flushable)
>> + flags = ACL_START_NO_FLUSH;
>> + else
>> + flags = ACL_START;
>> +
>> + hci_send_acl(hcon, skb, flags);
>
> There is another call to hci_send_acl() in l2cap. It is in
> l2cap_send_sframe(), but I'm still wondering if we shall flush those packets
> or not in the case flushable was set. Now I'm thinking that don't.
>
> Then you need to add the same check in l2cap_send_cmd to l2cap_send_sframe().
>
>> }
>>
>> static void l2cap_streaming_send(struct sock *sk)
>> @@ -2045,6 +2060,7 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, char __us
>> static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen)
>> {
>> struct sock *sk = sock->sk;
>> + struct hci_conn *hcon = l2cap_pi(sk)->conn->hcon;
>> struct bt_security sec;
>> int len, err = 0;
>> u32 opt;
>> @@ -2098,6 +2114,26 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, ch
>> bt_sk(sk)->defer_setup = opt;
>> break;
>>
>> + case BT_FLUSHABLE:
>> + if (get_user(opt, (u32 __user *) optval)) {
>> + err = -EFAULT;
>> + break;
>> + }
>> +
>> + if (opt > BT_FLUSHABLE_ON) {
>> + err = -EINVAL;
>> + break;
>> + }
>> +
>> + if (opt == BT_FLUSHABLE_OFF &&
>> + !lmp_no_flush_capable(hcon->hdev)) {
>
> I'm not really happy with !lmp_no_flush... 2 negatives in the same place, but
> that is the feature name. So we can't do too much here. Btw, the "No" in the
> feature name is making my brain hurt. ;)
>
> regards,
>
> --
> Gustavo F. Padovan
> http://profusion.mobi
>
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