[Toybox] Fallen down the rathole of netstat cleanup.

Rob Landley rob at landley.net
Fri Jun 10 19:01:52 PDT 2016


Alice says hi.

Ok, in toys/pending/netstat.c we have:

/*
 * used to get the flag values for route command.
 */
static void get_flag_value(char *flagstr, int flags)
{
  int i = 0;
  char *str = flagstr;
  static const char flagchars[] = "GHRDMDAC";
  static const unsigned flagarray[] = {
    RTF_GATEWAY, RTF_HOST, RTF_REINSTATE, RTF_DYNAMIC, RTF_MODIFIED,
    RTF_DEFAULT, RTF_ADDRCONF, RTF_CACHE
  };
  *str++ = 'U';

  while ( (*str = flagchars[i]) ) {
    if (flags & flagarray[i++]) ++str;
  }
}

The above is only ever called once:

    //Get flag Values
    get_flag_value(flag_val, flags & IPV4_MASK);

And IPV4_MASK is:

  #define IPV4_MASK \
   (RTF_GATEWAY|RTF_HOST|RTF_REINSTATE|RTF_DYNAMIC|RTF_MODIFIED)

Translation: the RTF_DEFAULT, RTF_ADDRCONF,and RTF_CACHE in the above
flagarray[] are filtered out before the call, and thus the "DAC" at the
end of flagchars[] can never be set. (The D is redundant, but hey.)

If this is right, shouldn't the flagarray[] and flagchars[] just be
shorter, so we don't need to mask because we're testing fewer values? Or
is it wrong, and we shouldn't be masking?

Confused,

Rob


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