On Tue, May 29, 2007 at 08:23:49AM +0300,
Pekka Savola <pekkas@xxxxxxxxxx> wrote
a message of 187 lines which said:
> 5) HIP wire format vs zone representation
..
> I may me misunderstanding this, but doesn't that imply that the
> authoritative DNS servers must implement Base16 and Base64 decoding support
> so that they can convert from BaseXX to the on-the-wire format?
First, there is traditionally no obligation, for a name server, to
support the zone file format. Many name servers take their data from
something else (a database, or a file with a different format). It is
not even clear if it was a good idea to specify one zone file format
in RFC 1035, since it is not "on the wire".
Second, a name server already needs a specific parser for each
resource record type. It does not seem it is different or more
complicated to parse Base64 than it is to parse a LOC record. See the
code in BIND's lib/dns/rdata/generic directory.
Some resource record types already require knowledge of Base 64, such
as CERT (RFC 4398) or DNSKEY (RFC 4034).
For fun, I included here the LOC parsing code of nsd :-)
/*
* Parses a specific part of rdata.
*
* Returns:
*
* number of elements parsed
* zero on error
*
*/
uint16_t *
zparser_conv_loc(region_type *region, char *str)
{
uint16_t *r;
uint32_t *p;
int i;
int deg, min, secs; /* Secs is stored times 1000. */
uint32_t lat = 0, lon = 0, alt = 0;
/* encoded defaults: version=0 sz=1m hp=10000m vp=10m */
uint8_t vszhpvp[4] = {0, 0x12, 0x16, 0x13};
char *start;
double d;
for(;;) {
deg = min = secs = 0;
/* Degrees */
if (*str == '\0') {
zc_error_prev_line("unexpected end of LOC data");
return NULL;
}
if (!parse_int(str, &str, °, "degrees", 0, 180))
return NULL;
if (!isspace(*str)) {
zc_error_prev_line("space expected after degrees");
return NULL;
}
++str;
/* Minutes? */
if (isdigit(*str)) {
if (!parse_int(str, &str, &min, "minutes", 0, 60))
return NULL;
if (!isspace(*str)) {
zc_error_prev_line("space expected after minutes");
return NULL;
}
++str;
}
/* Seconds? */
if (isdigit(*str)) {
start = str;
if (!parse_int(str, &str, &i, "seconds", 0, 60)) {
return NULL;
}
if (*str == '.' && !parse_int(str + 1, &str, &i, "seconds fraction", 0, 999)) {
return NULL;
}
if (!isspace(*str)) {
zc_error_prev_line("space expected after seconds");
return NULL;
}
if (sscanf(start, "%lf", &d) != 1) {
zc_error_prev_line("error parsing seconds");
}
if (d < 0.0 || d > 60.0) {
zc_error_prev_line("seconds not in range 0.0 .. 60.0");
}
secs = (int) (d * 1000.0 + 0.5);
++str;
}
switch(*str) {
case 'N':
case 'n':
lat = ((uint32_t)1<<31) + (deg * 3600000 + min * 60000 + secs);
break;
case 'E':
case 'e':
lon = ((uint32_t)1<<31) + (deg * 3600000 + min * 60000 + secs);
break;
case 'S':
case 's':
lat = ((uint32_t)1<<31) - (deg * 3600000 + min * 60000 + secs);
break;
case 'W':
case 'w':
lon = ((uint32_t)1<<31) - (deg * 3600000 + min * 60000 + secs);
break;
default:
zc_error_prev_line("invalid latitude/longtitude");
return NULL;
}
++str;
if (lat != 0 && lon != 0)
break;
if (!isspace(*str)) {
zc_error_prev_line("space expected after latitude/longitude");
return NULL;
}
++str;
}
/* Altitude */
if (*str == '\0') {
zc_error_prev_line("unexpected end of LOC data");
return NULL;
}
if (!isspace(*str)) {
zc_error_prev_line("space expected before altitude");
return NULL;
}
++str;
start = str;
/* Sign */
if (*str == '+' || *str == '-') {
++str;
}
/* Meters of altitude... */
(void)strtol(str, &str, 10);
switch(*str) {
case ' ':
case '\0':
case 'm':
break;
case '.':
if (!parse_int(str + 1, &str, &i, "altitude fraction", 0, 99)) {
return NULL;
}
if (!isspace(*str) && *str != '\0' && *str != 'm') {
zc_error_prev_line("altitude fraction must be a number");
return NULL;
}
break;
default:
zc_error_prev_line("altitude must be expressed in meters");
return NULL;
}
if (!isspace(*str) && *str != '\0')
++str;
if (sscanf(start, "%lf", &d) != 1) {
zc_error_prev_line("error parsing altitude");
}
alt = (uint32_t) (10000000.0 + d * 100 + 0.5);
if (!isspace(*str) && *str != '\0') {
zc_error_prev_line("unexpected character after altitude");
return NULL;
}
/* Now parse size, horizontal precision and vertical precision if any */
for(i = 1; isspace(*str) && i <= 3; i++) {
vszhpvp[i] = precsize_aton(str + 1, &str);
if (!isspace(*str) && *str != '\0') {
zc_error_prev_line("invalid size or precision");
return NULL;
}
}
/* Allocate required space... */
r = alloc_rdata(region, 16);
p = (uint32_t *) (r + 1);
memmove(p, vszhpvp, 4);
write_uint32(p + 1, lat);
write_uint32(p + 2, lon);
write_uint32(p + 3, alt);
return r;
}
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