On Mon, Mar 19, 2007 at 12:50:42PM -0400, Michael Wu wrote: > > I googled for radiotap specs but I didn't find anything useful. I added > > some small code to enforce the alignment rules you mention above. > > > I got the information on padding from: > http://madwifi.org/wiki/DevDocs/RadiotapHeader > > I don't remember how I managed to find that, but there it is. The packet-radiotap.c in Wireshark has the following comments: /* Written with info from: * * http://madwifi.org/wiki/DevDocs/RadiotapHeader * NetBSD's ieee80211_radiotap.h file */ /* * The NetBSD ieee80211_radiotap man page * (http://netbsd.gw.com/cgi-bin/man-cgi?ieee80211_radiotap+9+NetBSD-current) * says: * * Radiotap capture fields must be naturally aligned. That is, 16-, 32-, * and 64-bit fields must begin on 16-, 32-, and 64-bit boundaries, respec- * tively. In this way, drivers can avoid unaligned accesses to radiotap * capture fields. radiotap-compliant drivers must insert padding before a * capture field to ensure its natural alignment. radiotap-compliant packet * dissectors, such as tcpdump(8), expect the padding. */ Ciao Joerg -- Joerg Mayer <jmayer@xxxxxxxxx> We are stuck with technology when what we really want is just stuff that works. Some say that should read Microsoft instead of technology. - To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
