Wireshark mailing list archives
Re: dfilter functions
From: Dario Lombardo <lomato () gmail com>
Date: Mon, 7 Jan 2019 15:49:25 +0100
I agree. They look the same function, except for the limit about types. They look a bit confusing at a first glance. Unless they're needed for something, I'd remove one. On Mon, Jan 7, 2019 at 2:14 PM Peter Wu <peter () lekensteyn nl> wrote:
The online manual reflects 2.6.5, but the manual was updated in master, https://code.wireshark.org/review/27146 Perhaps size should be removed (as argued in that commit message)? Kind regards, Peter On Sun, Jan 06, 2019 at 02:20:22PM +0000, Michael Mann via Wireshark-dev wrote:len - Checks the string length of "string types" (FT_STRING, FT_STRINGZ,FT_UINT_STRING, FT_STRINGZPAD) or array length of "byte types" (FT_BYTES, FT_UINT_BYTES) and does a compare.Examples:len(smpp.message_id) > 10len(smpp.message) > 25 size - Checks the size of the field in a packet. Can be used forstrings/bytes like len() above, but can also be used for integer fields that vary in length (1-4 bytes)Examples:size(eth.type) == 2 (This is just for demonstrationpurposes. Obviously the size of the eth.type field could only be 2 but I couldn't quickly think of a "popular" field with varying integer length)size(tcp.options) > 7 count - Number of times a field is found in a single frame. This can beused to help identify "tunneling" or if multiple PDUs are in a single frame.Examples:count(ip.src) > 1 count(smpp.sequence_number) > 1 (Since sequence_number is requiredfor the packet, having more than one shows frames with multiple PDUs.-----Original Message----- From: Dario Lombardo <lomato () gmail com> To: Developer support list for Wireshark <wireshark-dev () wireshark org> Sent: Sun, Jan 6, 2019 4:35 am Subject: [Wireshark-dev] dfilter functions HiI've noticed that the online documentation about dfilter functionsjust talks about 2 of them, upper and lower:https://www.wireshark.org/docs/man-pages/wireshark-filter.html but there are more that are undocumented AFAICS: - len- size- count Can someone explain me their purpose and give a working example on someprotocol?Thanks.Dario. ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <wireshark-dev () wireshark org> Archives: https://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-request () wireshark org ?subject=unsubscribe
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Current thread:
- dfilter functions Dario Lombardo (Jan 06)
- <Possible follow-ups>
- Re: dfilter functions Michael Mann via Wireshark-dev (Jan 06)
- Re: dfilter functions Peter Wu (Jan 07)
- Re: dfilter functions Dario Lombardo (Jan 07)
- Re: dfilter functions Peter Wu (Jan 07)