RTL-lwIP-0.4: ares_expand_name.c File Reference

ares_expand_name.c File Reference

Include dependency graph for ares_expand_name.c:


Functions
int	name_length (const unsigned char encoded, const unsigned char abuf, int alen)
int	ares_expand_name (const unsigned char encoded, const unsigned char abuf, int alen, char *s, int enclen)

Function Documentation

int ares_expand_name	(	const unsigned char *	encoded,
		const unsigned char *	abuf,
		int	alen,
		char **	s,
		int *	enclen
	)

Definition at line 52 of file ares_expand_name.c.

References ARES_EBADNAME, ARES_ENOMEM, ARES_SUCCESS, INDIR_MASK, len, malloc, and name_length().

Referenced by ares_parse_a_reply(), ares_parse_ptr_reply(), and same_questions().

00054 {
00055   int len, indir = 0;
00056   char *q;
00057   const unsigned char *p;
00058 
00059   len = name_length(encoded, abuf, alen);
00060   if (len == -1)
00061     return ARES_EBADNAME;
00062 
00063   *s = malloc(len + 1);
00064   if (!*s)
00065     return ARES_ENOMEM;
00066   q = *s;
00067 
00068   /* No error-checking necessary; it was all done by name_length(). */
00069   p = encoded;
00070   while (*p)
00071     {
00072       if ((*p & INDIR_MASK) == INDIR_MASK)
00073         {
00074           if (!indir)
00075             {
00076               *enclen = p + 2 - encoded;
00077               indir = 1;
00078             }
00079           p = abuf + ((*p & ~INDIR_MASK) << 8 | *(p + 1));
00080         }
00081       else
00082         {
00083           len = *p;
00084           p++;
00085           while (len--)
00086             {
00087               if (*p == '.' || *p == '\\')
00088                 *q++ = '\\';
00089               *q++ = *p;
00090               p++;
00091             }
00092           *q++ = '.';
00093         }
00094     }
00095   if (!indir)
00096     *enclen = p + 1 - encoded;
00097 
00098   /* Nuke the trailing period if we wrote one. */
00099   if (q > *s)
00100     *(q - 1) = 0;
00101 
00102   return ARES_SUCCESS;
00103 }

Here is the call graph for this function:

int name_length	(	const unsigned char *	encoded,
		const unsigned char *	abuf,
		int	alen
	)	`[static]`

Definition at line 108 of file ares_expand_name.c.

References INDIR_MASK.

Referenced by ares_expand_name().

00110 {
00111   int n = 0, offset, indir = 0;
00112 
00113   /* Allow the caller to pass us abuf + alen and have us check for it. */
00114   if (encoded == abuf + alen)
00115     return -1;
00116 
00117   while (*encoded)
00118     {
00119       if ((*encoded & INDIR_MASK) == INDIR_MASK)
00120         {
00121           /* Check the offset and go there. */
00122           if (encoded + 1 >= abuf + alen)
00123             return -1;
00124           offset = (*encoded & ~INDIR_MASK) << 8 | *(encoded + 1);
00125           if (offset >= alen)
00126             return -1;
00127           encoded = abuf + offset;
00128 
00129           /* If we've seen more indirects than the message length,
00130            * then there's a loop.
00131            */
00132           if (++indir > alen)
00133             return -1;
00134         }
00135       else
00136         {
00137           offset = *encoded;
00138           if (encoded + offset + 1 >= abuf + alen)
00139             return -1;
00140           encoded++;
00141           while (offset--)
00142             {
00143               n += (*encoded == '.' || *encoded == '\\') ? 2 : 1;
00144               encoded++;
00145             }
00146           n++;
00147         }
00148     }
00149 
00150   /* If there were any labels at all, then the number of dots is one
00151    * less than the number of labels, so subtract one.
00152    */
00153   return (n) ? n - 1 : n;
00154 }

Generated on Wed Jan 14 12:59:00 2004 for RTL-lwIP-0.4 by

1.3.4

ares_expand_name.c File Reference

Functions

Function Documentation