RE: [PATCH v1 2/5] monitor/rfcomm: Add support for RPN frame decoding

[Gowtham Anandha Babu <gowtham.ab@samsung.com>]

Hi Szymon,

> -----Original Message-----
> From: linux-bluetooth-owner@vger.kernel.org [mailto:linux-bluetooth-
> owner@vger.kernel.org] On Behalf Of Szymon Janc
> Sent: Friday, December 05, 2014 4:33 PM
> To: Gowtham Anandha Babu
> Cc: 'Szymon Janc'; linux-bluetooth@vger.kernel.org;
> d.kasatkin@samsung.com; bharat.panda@samsung.com;
> cpgs@samsung.com
> Subject: Re: [PATCH v1 2/5] monitor/rfcomm: Add support for RPN frame
> decoding
> 
> Hi Gowtham,
> 
> On Friday 05 of December 2014 16:14:20 Gowtham Anandha Babu wrote:
> > Hi Szymon,
> >
> > > -----Original Message-----
> > > From: linux-bluetooth-owner@vger.kernel.org [mailto:linux-bluetooth-
> > > owner@vger.kernel.org] On Behalf Of Szymon Janc
> > > Sent: Thursday, December 04, 2014 8:48 PM
> > > To: Gowtham Anandha Babu
> > > Cc: linux-bluetooth@vger.kernel.org; d.kasatkin@samsung.com;
> > > bharat.panda@samsung.com; cpgs@samsung.com
> > > Subject: Re: [PATCH v1 2/5] monitor/rfcomm: Add support for RPN
> > > frame decoding
> > >
> > > Hi Gowtham,
> > >
> > > On Wed, Dec 3, 2014 at 1:01 PM, Gowtham Anandha Babu
> > > <gowtham.ab@samsung.com> wrote:
> > > > Changes made to decode RPN frame in RFCOMM for btmon.
> > > >
> > > >       RFCOMM: Unnumbered Info with Header Check (UIH)(0xef)
> > > >          Address: 0x03 cr 1 dlci 0x00
> > > >          Control: 0xef poll/final 0
> > > >          Length: 10
> > > >          FCS: 0x70
> > > >          MCC Message type: Remote Port Negotiation Command
> CMD(0x24)
> > > >            Length: 8
> > > >            dlci 32
> > > >            br 3 db 2 sb 0 p 0 pt 0 xi 0 xo 0
> > > >            rtri 0 rtro 0 rtci 0 rtco 0 xon 17 xoff 19
> > > >            pm 0x3f7f
> > > > ---
> > > >  monitor/rfcomm.c | 73
> > > >
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > >  1 file changed, 73 insertions(+)
> > > >
> > > > diff --git a/monitor/rfcomm.c b/monitor/rfcomm.c index
> > > > cd50c8c..62b52cc 100644
> > > > --- a/monitor/rfcomm.c
> > > > +++ b/monitor/rfcomm.c
> > > > @@ -63,6 +63,18 @@ static char *cr_str[] = {
> > > >  #define GET_V24_IC(sigs)       ((sigs & 0x40) >> 6)
> > > >  #define GET_V24_DV(sigs)       ((sigs & 0x80) >> 7)
> > > >
> > > > +/* RPN macros */
> > > > +#define GET_RPN_DB(parity)     (parity & 0x03)
> > > > +#define GET_RPN_SB(parity)     ((parity & 0x04) >> 2)
> > > > +#define GET_RPN_PARITY(parity) ((parity & 0x08) >> 3) #define
> > > > +GET_RPN_PTYPE(parity)  ((parity & 0x03) >> 3)
> > > > +#define GET_RPN_XIN(io)                (io & 0x01)
> > > > +#define GET_RPN_XOUT(io)       ((io & 0x02) >> 1)
> > > > +#define GET_RPN_RTRI(io)       ((io & 0x04) >> 2)
> > > > +#define GET_RPN_RTRO(io)       ((io & 0x08) >> 3)
> > > > +#define GET_RPN_RTCI(io)       ((io & 0x10) >> 4)
> > > > +#define GET_RPN_RTCO(io)       ((io & 0x20) >> 5)
> > > > +
> > > >  struct rfcomm_lhdr {
> > > >         uint8_t address;
> > > >         uint8_t control;
> > > > @@ -77,6 +89,16 @@ struct rfcomm_lmsc {
> > > >         uint8_t break_sig;
> > > >  } __attribute__((packed));
> > > >
> > > > +struct rfcomm_rpn {
> > > > +       uint8_t dlci;
> > > > +       uint8_t bit_rate;
> > > > +       uint8_t parity;
> > > > +       uint8_t io;
> > > > +       uint8_t xon;
> > > > +       uint8_t xoff;
> > > > +       uint16_t pm;
> > > > +} __attribute__ ((packed));
> > > > +
> > > >  struct rfcomm_lmcc {
> > > >         uint8_t type;
> > > >         uint16_t length;
> > > > @@ -138,6 +160,55 @@ done:
> > > >         return true;
> > > >  }
> > > >
> > > > +static inline bool mcc_rpn(struct rfcomm_frame *rfcomm_frame,
> > > > +uint8_t
> > > > +indent) {
> > > > +       struct l2cap_frame *frame = &rfcomm_frame->l2cap_frame;
> > > > +       struct rfcomm_rpn rpn;
> > > > +
> > > > +       if (!l2cap_frame_get_u8(frame, &rpn.dlci))
> > > > +               return false;
> > > > +
> > > > +       print_field("%*cdlci %d", indent, ' ',
> > > > + RFCOMM_GET_DLCI(rpn.dlci));
> > > > +
> > > > +       if (frame->size < 7)
> > > > +               goto done;
> > > > +
> > > > +       /* port value octets (optional) */
> > > > +
> > > > +       if (!l2cap_frame_get_u8(frame, &rpn.bit_rate))
> > > > +               return false;
> > > > +
> > > > +       if (!l2cap_frame_get_u8(frame, &rpn.parity))
> > > > +               return false;
> > > > +
> > > > +       if (!l2cap_frame_get_u8(frame, &rpn.io))
> > > > +               return false;
> > > > +
> > > > +       print_field("%*cbr %d db %d sb %d p %d pt %d xi %d xo %d",
> > indent, '
> > > ',
> > > > +               rpn.bit_rate, GET_RPN_DB(rpn.parity),
> > GET_RPN_SB(rpn.parity),
> > > > +               GET_RPN_PARITY(rpn.parity), GET_RPN_PTYPE(rpn.parity),
> > > > +               GET_RPN_XIN(rpn.io), GET_RPN_XOUT(rpn.io));
> > > > +
> > > > +       if (!l2cap_frame_get_u8(frame, &rpn.xon))
> > > > +               return false;
> > > > +
> > > > +       if (!l2cap_frame_get_u8(frame, &rpn.xoff))
> > > > +               return false;
> > > > +
> > > > +       print_field("%*crtri %d rtro %d rtci %d rtco %d xon %d xoff %d",
> > > > +               indent, ' ', GET_RPN_RTRI(rpn.io), GET_RPN_RTRO(rpn.io),
> > > > +               GET_RPN_RTCI(rpn.io), GET_RPN_RTCO(rpn.io), rpn.xon,
> > > > +               rpn.xoff);
> > > > +
> > > > +       if (!l2cap_frame_get_be16(frame, &rpn.pm))
> > > > +               return false;
> > > > +
> > > > +       print_field("%*cpm 0x%04x", indent, ' ',
> > > > + __bswap_16(rpn.pm));
> > >
> > > This __bswap_16 is invalid since rpn.pm was already converted to
> > > host
> > order
> > > by l2cap_frame_get_be16(). (It wouldn't work correctly on BE arch
> anyway).
> > >
> > > Also this was causing build problems under Android. If you are able
> > > to
> > build-
> > > test under Android please do so. If not then at least point this in
> > > cover
> > letter
> > > or patch comment that code was tested only under Linux).
> > >
> > > I've fixed this myself but please pay attention to this with any
> > > future submission.
> > >
> >
> > Sure I will mention the tested platform details for future submission.
> >
> > Btw without __bswap_16(), rpn.pm and pn.mtu will be different from the
> > hcidump logs.
> >
> > This is captured by removing __bswap_16().
> >
> > Btmon log:
> >       RFCOMM: Unnumbered Info with Header Check (UIH)(0xef)
> >          Address: 0x03 cr 1 dlci 0x00
> >          Control: 0xef poll/final 0
> >          Length: 10
> >          FCS: 0x70
> >          MCC Message type: DLC Parameter Negotiation CMD(0x20)
> >            Length: 8
> >            dlci 6 frame_type 0 credit_flow 15 pri 3
> >            ack_timer 0 frame_size 32256 max_retrans 0 credits 1
> >
> > Hcidump log:
> >       RFCOMM(s): PN CMD: cr 1 dlci 0 pf 0 ilen 10 fcs 0x70 mcc_len 8
> >       dlci 6 frame_type 0 credit_flow 15 pri 3 ack_timer 0
> >       frame_size 126 max_retrans 0 credits 1
> >
> > The rpn.pm is fine. That may be printed without doing __bswap_16() also.
> >
> > But in the above PN frame, frame_size is different from actual hcidump
> > trace.
> > I cross checked with PTS logs, it was same as the hcidump trace.
> > So, if it is causing build problems under Android, use
> > l2cap_frame_get_le16()
> > Instead of l2cap_frame_get_be16() for pn.mtu.
> >
> > If we are consistent with hcidump, then replace the be16() by le16()
> > for both pn.mtu and rpn.pm.
> >
> > After replacing the le16() function:
> > Btmon logs looks like:
> >
> >       RFCOMM: Unnumbered Info with Header Check (UIH)(0xef)
> >          Address: 0x03 cr 1 dlci 0x00
> >          Control: 0xef poll/final 0
> >          Length: 10
> >          FCS: 0x70
> >          MCC Message type: DLC Parameter Negotiation CMD(0x20)
> >            Length: 8
> >            dlci 6 frame_type 0 credit_flow 15 pri 3
> >            ack_timer 0 frame_size 126 max_retrans 0 credits 1
> >
> > What do you think ?
> 
> If value is LE then l2cap_frame_get_le16() should be used.
> (Same issue affects rpn.pm mcc_rpn(), right?)
> 

Yes you are right. We have to use l2cap_frame_get_le16() for fetching both rpn.pm and pn.mtu.
I hope it will not cause any Android build problem.

> >
> > > > +
> > > > +done:
> > > > +       return true;
> > > > +}
> > > > +
> > > >  struct mcc_data {
> > > >         uint8_t type;
> > > >         const char *str;
> > > > @@ -201,6 +272,8 @@ static inline bool mcc_frame(struct
> > > > rfcomm_frame
> > > *rfcomm_frame, uint8_t indent)
> > > >         switch (type) {
> > > >         case RFCOMM_MSC:
> > > >                 return mcc_msc(rfcomm_frame, indent+2);
> > > > +       case RFCOMM_RPN:
> > > > +               return mcc_rpn(rfcomm_frame, indent+2);
> > > >         default:
> > > >                 packet_hexdump(frame->data, frame->size);
> > > >         }
> > > > --
> > > > 1.9.1
> > > >
> > > > --
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> > >
> > >
> > >
> > > --
> > > pozdrawiam
> > > Szymon K. Janc
> > > szymon.janc@gmail.com
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-bluetooth"
> > in
> > > the body of a message to majordomo@vger.kernel.org More majordomo
> > > info at  http://vger.kernel.org/majordomo-info.html
> >
> >
> > Regards,
> > Gowtham Anandha Babu
> >
> > --
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> 
> --
> Best regards,
> Szymon Janc
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
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Regards,
Gowtham Anandha Babu