From owner-freebsd-security  Tue Jan 25 21: 5:52 2000
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Date: Wed, 26 Jan 2000 13:04:42 +0800 (+0800)
From: Michael Robinson <robinson@netrinsics.com>
Message-Id: <200001260504.NAA49214@netrinsics.com>
To: archie@whistle.com, sh@eclipse.net.uk
Subject: Re: tcpdump
Cc: freebsd-security@freebsd.org, robinson@netrinsics.com
In-Reply-To: <200001252153.NAA66515@bubba.whistle.com>
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Archie Cobbs <archie@whistle.com> writes:
>So.. how do you get tcpdump to spit forth ascii?

This works for me:

------------------------------------
u_char template[]=
   "\n\t                                                           \0"; 
u_char hex[] = "0123456789ABCDEF";

/*  
 * By default, print the packet out in hex.
 *
 * (BTW, please don't send us patches to print the packet out in ascii)
 */
void
default_print(register const u_char *bp, register u_int length)
{
    u_char buffer[62], c;
    u_int i=0, o, p;

    while (i < length) {
        o = i % 16;  
        if (o == 0) {
            if (i > 0) 
                fputs(buffer, stdout);
            bcopy(template, buffer, 62);
        }
        c = bp[i++];
        p = 2 + o*2 + (o/2);
        buffer[p++] = hex[(c & 0xF0)>>4];
        buffer[p++] = hex[c & 0x0F];
        if (c >= ' ' && c <= '~') {
            buffer[o+45] = c;
        } else {
            buffer[o+45] = '.';
        }
    }
    if (i % 16) {
        fputs(buffer, stdout);
    }
}


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