Hi Alain,
> > This change adds support for reporting the BT_PKT_STATUS to the socket
> > CMSG data to allow the implementation of a packet loss correction on
> > erronous data received on the SCO socket.
> >
> > The patch was partially developed by Marcel Holtmann and validated by
> > Hsin-yu Chao
> >
> > Signed-off-by: Alain Michaud <alainm@xxxxxxxxxxxx>
> >
> > ---
> >
> > include/net/bluetooth/bluetooth.h | 8 +++++++
> > include/net/bluetooth/sco.h | 3 +++
> > net/bluetooth/af_bluetooth.c | 3 +++
> > net/bluetooth/hci_core.c | 1 +
> > net/bluetooth/sco.c | 35 +++++++++++++++++++++++++++++++
> > 5 files changed, 50 insertions(+)
>
> I already had this patch in my tree for testing, but then realized that I gave you a bad example on how to handle this.
>
> So we should not use the same constants for CMSG and socket options. Fundamentally the socket semantics use SO_foo for enabling an aux data transmission and they use SCM_bar for the CMSG portion.
>
> >
> > diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
> > index 3fa7b1e3c5d9..85e6c5754448 100644
> > --- a/include/net/bluetooth/bluetooth.h
> > +++ b/include/net/bluetooth/bluetooth.h
> > @@ -147,6 +147,8 @@ struct bt_voice {
> > #define BT_MODE_LE_FLOWCTL 0x03
> > #define BT_MODE_EXT_FLOWCTL 0x04
> >
> > +#define BT_PKT_STATUS 16
> > +
> > __printf(1, 2)
> > void bt_info(const char *fmt, ...);
> > __printf(1, 2)
> > @@ -275,6 +277,7 @@ struct bt_sock {
> > struct sock *parent;
> > unsigned long flags;
> > void (*skb_msg_name)(struct sk_buff *, void *, int *);
> > + void (*skb_put_cmsg)(struct sk_buff *, struct msghdr *, struct sock *);
> > };
> >
> > enum {
> > @@ -324,6 +327,10 @@ struct l2cap_ctrl {
> > struct l2cap_chan *chan;
> > };
> >
> > +struct sco_ctrl {
> > + u8 pkt_status;
> > +};
> > +
> > struct hci_dev;
> >
> > typedef void (*hci_req_complete_t)(struct hci_dev *hdev, u8 status, u16 opcode);
> > @@ -350,6 +357,7 @@ struct bt_skb_cb {
> > u8 incoming:1;
> > union {
> > struct l2cap_ctrl l2cap;
> > + struct sco_ctrl sco;
> > struct hci_ctrl hci;
> > };
> > };
> > diff --git a/include/net/bluetooth/sco.h b/include/net/bluetooth/sco.h
> > index f40ddb4264fc..7f0d7bdc53f6 100644
> > --- a/include/net/bluetooth/sco.h
> > +++ b/include/net/bluetooth/sco.h
> > @@ -46,4 +46,7 @@ struct sco_conninfo {
> > __u8 dev_class[3];
> > };
> >
> > +/* CMSG flags */
> > +#define SCO_CMSG_PKT_STATUS 0x0001
> > +
> > #endif /* __SCO_H */
> > diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
> > index 3fd124927d4d..d0abea8d08cc 100644
> > --- a/net/bluetooth/af_bluetooth.c
> > +++ b/net/bluetooth/af_bluetooth.c
> > @@ -286,6 +286,9 @@ int bt_sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> > if (msg->msg_name && bt_sk(sk)->skb_msg_name)
> > bt_sk(sk)->skb_msg_name(skb, msg->msg_name,
> > &msg->msg_namelen);
> > +
> > + if (bt_sk(sk)->skb_put_cmsg)
> > + bt_sk(sk)->skb_put_cmsg(skb, msg, sk);
> > }
> >
> > skb_free_datagram(sk, skb);
> > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> > index 51d399273276..7b5e46198d99 100644
> > --- a/net/bluetooth/hci_core.c
> > +++ b/net/bluetooth/hci_core.c
> > @@ -4549,6 +4549,7 @@ static void hci_scodata_packet(struct hci_dev *hdev, struct sk_buff *skb)
> >
> > if (conn) {
> > /* Send to upper protocol */
> > + bt_cb(skb)->sco.pkt_status = flags & 0x03;
> > sco_recv_scodata(conn, skb);
> > return;
> > } else {
> > diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
> > index c8c3d38cdc7b..f6b54853e547 100644
> > --- a/net/bluetooth/sco.c
> > +++ b/net/bluetooth/sco.c
> > @@ -66,6 +66,7 @@ struct sco_pinfo {
> > bdaddr_t dst;
> > __u32 flags;
> > __u16 setting;
> > + __u32 cmsg_mask;
> > struct sco_conn *conn;
> > };
> >
> > @@ -449,6 +450,15 @@ static void sco_sock_close(struct sock *sk)
> > sco_sock_kill(sk);
> > }
> >
> > +static void sco_skb_put_cmsg(struct sk_buff *skb, struct msghdr *msg,
> > + struct sock *sk)
> > +{
> > + if (sco_pi(sk)->cmsg_mask & SCO_CMSG_PKT_STATUS)
> > + put_cmsg(msg, SOL_BLUETOOTH, BT_PKT_STATUS,
>
> This needs an extra BT_SCM_PKT_STATUS constant.
> Since we don't have this name space defined yet, I'm assuming I just start with 01 for this.
hmmm. Since we used to have a few HCI ones, just for the sake of never ever conflicting, I would say start after them.
/* CMSG flags */
#define HCI_CMSG_DIR 0x0001
#define HCI_CMSG_TSTAMP 0x0002
So lets start with 3.
I think even for the socket numbering options we started with 4 to just make sure we never ever come into some weird conflict. Some of this code is 18+ years old ;)
Regards
Marcel
