Capturing Data from Tshark

Tshark is a command line packet sniffer. I am trying to find a way to get information from the packet开发者_Python百科s, put it in a variable and do some regular expression on it.

Right now, I am getting this from tshark:

Capturing on eth0
  0.000000 74.125.71.116 -> 112.204.184.111 TCP http > 55828 [ACK] Seq=1 Ack=1 Win=6434 Len=0 TSV=2558834852 TSER=542043
  0.000035 112.204.184.111 -> 74.125.71.116 HTTP Continuation or non-HTTP traffic
  0.000043 112.204.184.111 -> 74.125.71.116 HTTP Continuation or non-HTTP traffic

Note: I am using Ruby.

You can use tshark itself without another utility. This command prints out all URI's from packets as they arrive:

$ tshark -R http.request.full_uri -T fields -e http.request.full_uri -i en0 

You can refine the display filter (the -R parameter) to better match your requirements. It even supports Perl regular expression matching:

# Mac OS X
$ tshark -R 'http.request.full_uri matches "\\.jpg\|\\.js"' -T fields -e http.request.full_uri -i en0 

Example output from visiting youtube.com:

$ tshark -R 'http.request.full_uri matches "\\.jpg\|\\.js"' -T fields -e http.request.full_uri -i en0
Capturing on en0

http://s.ytimg.com/yt/jsbin/www-core-vfl3_mVgh.js
http://s.ytimg.com/yt/jsbin/www-subscriptions-vfl5HwfxW.js
http://i2.ytimg.com/i/QMbqH7xJu5aTAPQ9y_U7WQ/1.jpg?v=95416b
http://i1.ytimg.com/vi/4R0BAjrZqyY/default.jpg
http://i4.ytimg.com/i/KVtW8ExxO21F2sNLtwrq_w/1.jpg?v=a1fa0c
http://i3.ytimg.com/vi/z3U0udLH974/default.jpg
http://i2.ytimg.com/vi/arKyyDRsE_8/default.jpg
http://i2.ytimg.com/vi/y1TGz-fEyiE/default.jpg
http://i2.ytimg.com/vi/-tc983PZK3o/default.jpg
http://i2.ytimg.com/vi/1yT2rrTyMK8/default.jpg
http://i4.ytimg.com/vi/cciUXpITsu0/default.jpg
http://i2.ytimg.com/vi/uG0dimAxHpI/default.jpg
http://i2.ytimg.com/vi/eP9P50kbzTk/default.jpg
http://i1.ytimg.com/vi/ppBe0T412uU/default.jpg
http://i1.ytimg.com/vi/8360wVLtEuk/default.jpg
http://i4.ytimg.com/vi/G_yB7wdTxa0/default.jpg
http://i4.ytimg.com/vi/gcZxoLs3NIU/default.jpg
http://i1.ytimg.com/i/po2fJvnalYlwN97ehhyfBQ/1.jpg?v=b8e52a
http://i1.ytimg.com/vi/D2Xjj_ra8lQ/default.jpg
http://i1.ytimg.com/vi/PewewGu9gp8/default.jpg
http://i1.ytimg.com/vi/P9FkRD6ppGo/default.jpg
http://i3.ytimg.com/vi/vpZ4SMU4znQ/default.jpg
http://i3.ytimg.com/vi/jrrSGulNOLc/default.jpg
http://i3.ytimg.com/vi/FJtTzQfdnoQ/default.jpg
http://i3.ytimg.com/vi/68sEHPpQXes/default.jpg
http://i2.ytimg.com/vi/iWYqsaJk_U8/default.jpg
http://i4.ytimg.com/vi/7Prb8DbdfwY/default.jpg
http://i1.ytimg.com/vi/HJFlxLJSX8E/default.jpg
http://i1.ytimg.com/vi/ta6Vu_v7VLg/default.jpg
http://i1.ytimg.com/vi/Hq7NtDSIErE/default.jpg
http://i4.ytimg.com/vi/Sjdj7qhcTuw/default.jpg
http://i3.ytimg.com/vi/Nm3Acf3_oMY/default.jpg
http://i3.ytimg.com/vi/BpsrThXh_gM/default.jpg
http://i3.ytimg.com/vi/Z3yapgewktY/default.jpg
http://i3.ytimg.com/vi/2UFc1pr2yUU/default.jpg
http://i2.ytimg.com/vi/q_Bt6NwD4FY/default.jpg
http://i2.ytimg.com/vi/uTAAlzABzBA/default.jpg
http://i2.ytimg.com/vi/iRLUY6dMF8k/default.jpg
http://i2.ytimg.com/vi/-cDH6CYzTAw/default.jpg
http://i1.ytimg.com/vi/8p6Fn8R1Rc4/default.jpg
http://i1.ytimg.com/vi/T8gDQWdlW6A/default.jpg
http://i2.ytimg.com/vi/ERTcZV7uTFU/default.jpg
http://i1.ytimg.com/vi/PyxgwA6PvnI/default.jpg
http://i1.ytimg.com/vi/xUGlezOCvu4/default.jpg
http://i1.ytimg.com/vi/Ljb6Mne8Mfc/default.jpg

Note: In Windows, I've seentshark print all URIs in a particular packet in one line without delimiters (e.g., "http://www.google.comhttp://www.google.com/logos/classicplus.png"). Only some packets were affected by this.

You could either pipe this data into a file which you then open and parse with Ruby, or you could use a Ruby lib that can access the same data, such as: http://sourceforge.net/apps/trac/rubypcap/