Date: Fri, 12 Nov 2010 07:18:46 -0800 From: Maksim Yevmenkin <maksim.yevmenkin@gmail.com> To: Andrzej Tobola <ato@iem.pw.edu.pl> Subject: Re: l2ping - strange seq_no Message-ID: <AANLkTimS12wNKGqwWxPFLATPi=ObT8wvoDR41=8rq3D6@mail.gmail.com> In-Reply-To: <20101112070051.GA48569@amp2.iem.pw.edu.pl> References: <64FA2044DA694411995A309FF342396C@marekdesktop> <B9E22A10-F431-456A-8127-2D6B26C99424@gmail.com> <20101112050506.GA18796@amp2.iem.pw.edu.pl> <AANLkTimTm457Zknv6Spk4A%2BxECy7YsoXgk7SoSUPBA8X@mail.gmail.com> <20101112062852.GA39843@amp2.iem.pw.edu.pl> <AANLkTikRfGYg30ThupSsDv9Wxt8EmJxHXRY0bGmUkTi=@mail.gmail.com> <20101112064459.GA45107@amp2.iem.pw.edu.pl> <20101112070051.GA48569@amp2.iem.pw.edu.pl>
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Andrzej, > The last question - is it OK that seq_no has strange values or jumps: > > z2% l2ping -a FF1 > 4 bytes from FF1 seq_no=1633905441 time=798.277 ms result=0 > 4 bytes from FF1 seq_no=1633905441 time=13.756 ms result=0 > 4 bytes from FF1 seq_no=1633905441 time=28.755 ms result=0 > 4 bytes from FF1 seq_no=1633905441 time=25.755 ms result=0 > 4 bytes from FF1 seq_no=1633905441 time=28.761 ms result=0 > 4 bytes from FF1 seq_no=1633905441 time=32.018 ms result=0 > ^C > z2% l2ping -a FF2 > 0 bytes from FF2 seq_no=0 time=37.552 ms result=0x9 > 0 bytes from FF2 seq_no=1 time=5.754 ms result=0x9 > 0 bytes from FF2 seq_no=2 time=5.756 ms result=0x9 > 4 bytes from FF2 seq_no=1633905441 time=107.755 ms result=0 > 4 bytes from FF2 seq_no=1633905441 time=30.758 ms result=0 > 4 bytes from FF2 seq_no=1633905441 time=25.759 ms result=0 > 4 bytes from FF2 seq_no=1633905441 time=27.757 ms result=0 > 4 bytes from FF2 seq_no=1633905441 time=25.754 ms result=0 > 4 bytes from FF2 seq_no=1633905441 time=93.766 ms result=0 > 4 bytes from FF2 seq_no=1633905441 time=65.763 ms result=0 > 4 bytes from FF2 seq_no=1633905441 time=87.759 ms result=0 > 4 bytes from FF2 seq_no=1633905441 time=24.758 ms result=0 > ^C > z2% l2ping -a VV1 > 44 bytes from VV1 seq_no=0 time=3887.731 ms result=0 > 44 bytes from VV1 seq_no=1 time=21.762 ms result=0 > 44 bytes from VV1 seq_no=2 time=27.014 ms result=0 > 44 bytes from VV1 seq_no=3 time=9.761 ms result=0 > 44 bytes from VV1 seq_no=4 time=47.760 ms result=0 > 44 bytes from VV1 seq_no=5 time=14.017 ms result=0 > 44 bytes from VV1 seq_no=6 time=16.852 ms result=0 > 44 bytes from VV1 seq_no=7 time=27.762 ms result=0 > 44 bytes from VV1 seq_no=8 time=53.765 ms result=0 > 44 bytes from VV1 seq_no=9 time=31.762 ms result=0 > 44 bytes from VV1 seq_no=10 time=13.765 ms result=0 > 44 bytes from VV1 seq_no=11 time=34.762 ms result=0 > > or it signals some memory corruption ? not necessarily. l2cap does not have sequence numbers in protocol headers (like ip/icmp does), so l2cap(8) fakes sequence numbers by putting them into l2cap echo request packet payload. some devices return original payload in l2cap echo response thus making it easy to get sequence numbers back. some devices do not return any payload back (i.e. l2cap(8) will not get any sequence numbers back). in your case, payload is returned, but it appears to be different (constant?). what kind are FF1 and FF2 devices? could you please install hcidump utility from ports (i think its under net/comm) and get a trace to see what payload is being sent out and what payload is received back? thanks, max
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