Return-Path: MIME-Version: 1.0 In-Reply-To: <1415365587-6217-3-git-send-email-gowtham.ab@samsung.com> References: <1415365587-6217-1-git-send-email-gowtham.ab@samsung.com> <1415365587-6217-3-git-send-email-gowtham.ab@samsung.com> Date: Fri, 7 Nov 2014 16:26:51 +0200 Message-ID: Subject: Re: [PATCH v1 2/4] monitor/rfcomm: Add support for printing RFCOMM hdr From: Luiz Augusto von Dentz To: Gowtham Anandha Babu Cc: "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, Nov 7, 2014 at 3:06 PM, Gowtham Anandha Babu wrote: > Changes made to decode RFCOMM hdr and print the same. > > RFCOMM: Unnumbered Info with Header Check (UIH)(0xef) > Address: 0x01 cr 0 dlci 0x00 > Control: 0xef poll/final 0 > Length: 10 > FCS: 0xaa > 81 11 20 e0 27 00 9a 02 00 07 aa .. .'...... > > --- > monitor/rfcomm.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 47 insertions(+), 3 deletions(-) > > diff --git a/monitor/rfcomm.c b/monitor/rfcomm.c > index 155bde2..a70c404 100644 > --- a/monitor/rfcomm.c > +++ b/monitor/rfcomm.c > @@ -44,6 +44,11 @@ > #include "sdp.h" > #include "rfcomm.h" > > +#define GET_LEN8(length) ((length & 0xfe) >> 1) > +#define GET_LEN16(length) ((length & 0xfffe) >> 1) > +#define GET_CR(type) ((type & 0x02) >> 1) > +#define GET_PF(ctr) (((ctr) >> 4) & 0x1) > + > struct rfcomm_lhdr { > uint8_t address; > uint8_t control; > @@ -57,6 +62,24 @@ struct rfcomm_frame { > struct l2cap_frame l2cap_frame; > }; > > +static void print_rfcomm_hdr(struct rfcomm_frame *rfcomm_frame, uint8_t indent) > +{ > + struct rfcomm_lhdr hdr = rfcomm_frame->hdr; > + > + /* Address field */ > + print_field("%*cAddress: 0x%2.2x cr %d dlci 0x%2.2x", indent, ' ', > + hdr.address, GET_CR(hdr.address), > + RFCOMM_GET_DLCI(hdr.address)); > + > + /* Control field */ > + print_field("%*cControl: 0x%2.2x poll/final %d", indent, ' ', > + hdr.control, GET_PF(hdr.control)); > + > + /* Length and FCS */ > + print_field("%*cLength: %d", indent, ' ', hdr.length); > + print_field("%*cFCS: 0x%2.2x", indent, ' ', hdr.fcs); > +} > + > struct rfcomm_data { > uint8_t frame; > const char *str; > @@ -73,12 +96,13 @@ static const struct rfcomm_data rfcomm_table[] = { > > void rfcomm_packet(const struct l2cap_frame *frame) > { > - uint8_t ctype; > + uint8_t ctype, length, ex_length, indent = 1; > const char *frame_str, *frame_color; > struct l2cap_frame *l2cap_frame; > struct rfcomm_frame rfcomm_frame; > struct rfcomm_lhdr hdr; > const struct rfcomm_data *rfcomm_data = NULL; > + const void *ptr; > int i; > > l2cap_frame_pull(&rfcomm_frame.l2cap_frame, frame, 0); > @@ -89,9 +113,24 @@ void rfcomm_packet(const struct l2cap_frame *frame) > goto fail; > > if (!l2cap_frame_get_u8(l2cap_frame, &hdr.address) || > - !l2cap_frame_get_u8(l2cap_frame, &hdr.control)) > + !l2cap_frame_get_u8(l2cap_frame, &hdr.control) || > + !l2cap_frame_get_u8(l2cap_frame, &length)) > goto fail; > > + /* length maybe 1 or 2 octets */ > + if (RFCOMM_TEST_EA(length)) > + hdr.length = (uint16_t) GET_LEN8(length); > + else { > + if (!l2cap_frame_get_u8(l2cap_frame, &ex_length)) > + goto fail; > + hdr.length = ((uint16_t)length << 8) | ex_length; > + hdr.length = GET_LEN16(hdr.length); > + } > + > + /* fetching FCS by frame offset */ > + ptr = (l2cap_frame->data)+l2cap_frame->size-1; > + hdr.fcs = *(uint8_t *)(ptr); You should probably use l2cap_frame_pull followed by l2cap_frame_get_u8 so we actually check if the frame is too short. Btw, the format looks much better now. > /* Decoding frame type */ > ctype = RFCOMM_GET_TYPE(hdr.control); > > @@ -122,7 +161,12 @@ void rfcomm_packet(const struct l2cap_frame *frame) > "(0x%2.2x)", ctype); > > rfcomm_frame.hdr = hdr; > - packet_hexdump(l2cap_frame->data, l2cap_frame->size); > + print_rfcomm_hdr(&rfcomm_frame, indent); > + > + /* UIH frame */ > + if(ctype == 0xef) > + packet_hexdump(l2cap_frame->data, l2cap_frame->size); > + > return; > > fail: > -- > 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 -- Luiz Augusto von Dentz