Return-Path: MIME-Version: 1.0 In-Reply-To: <000601d0107c$32fcecd0$98f6c670$@samsung.com> References: <1417608081-27926-1-git-send-email-gowtham.ab@samsung.com> <000501d01078$707a0830$516e1890$@samsung.com> <1762326.kKINeE8oQE@uw000953> <000601d0107c$32fcecd0$98f6c670$@samsung.com> Date: Fri, 5 Dec 2014 13:47:39 +0200 Message-ID: Subject: Re: [PATCH v1 2/5] monitor/rfcomm: Add support for RPN frame decoding From: Luiz Augusto von Dentz To: Gowtham Anandha Babu Cc: Szymon Janc , "linux-bluetooth@vger.kernel.org" , Dmitry Kasatkin , Bharat Panda , cpgs@samsung.com Content-Type: text/plain; charset=UTF-8 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Gowtham, On Fri, Dec 5, 2014 at 1:10 PM, 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: 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 >> > > 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. Actually you need to check what endianess for the protocol, the kernel seems to treat RFCOMM as little endian which I suppose is the correct byte order otherwise we would not be able to qualify or even interoperate with other devices. >> > >> > > > + >> > > > +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 >> > > > >> > > > -- >> > > > 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 >> > > >> > > >> > > >> > > -- >> > > 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 >> > >> > -- >> > 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 >> >> -- >> Best regards, >> Szymon Janc >> -- >> 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 > > -- > 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 -- Luiz Augusto von Dentz