tcpdump -E doesn't work for 3des-cbc/hmac-md5

[Michael Mueller <m.mueller99 () kay-mueller de>]

Hi,

Tcpdump -E doesn't work for 3des-cbc encryption with hmac-md5 
authentication (tested with tcpdump-2004.09.22 on Linux 2.6). The reason 
is that in esp_print_decode_onesecret(), print-esp.c authlen is left 0 
instead of setting it to 12 for *-cbc encryptions. The 12 byte authlen 
is required for

        hmac-md5        by rfc2403
        hmac-sha1       by rfc2404

and seems to have the same value for other authentication algorithms 
too. I don't think that authlen should depend on the encryption 
algorithm used. I append a patch that sets it to 12. I hope that this is 
good for all cases. Otherwise specifying authlen on the command line 
would be an alternative.

Michael
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