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Network Working Group C. Davis
Internet Draft Kapor Enterprises
Updates: RFCs 1034, 1035 P. Vixie
Vixie Enterprises
T. Goodwin
PIPEX
I. Dickinson
University of Warwick
November
December 1994
A Means for Expressing Location Information in the Domain Name System
Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet- Drafts as reference
material or to cite them other than as ``work in progress.''
To learn the current status of any Internet-Draft, please check the
``1id-abstracts.txt'' listing contained in the Internet- Drafts
Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
ftp.isi.edu (US West Coast).
1. Abstract
This Internet-Draft describes a mechanism to allow the DNS to carry
location information about hosts, networks, and subnets. Such
information for a small subset of hosts is currently contained in the
flat-file UUCP maps. However, just as the DNS replaced the use of
HOSTS.TXT to carry host and network address information, it is
possible to replace the UUCP maps as carriers of location
information.
This Internet-Draft defines the format of a new Resource Record (RR)
for the Domain Name System (DNS), and reserves a corresponding DNS
type mnemonic (LOC) and numerical code (29).
This Internet-Draft assumes that the reader is familiar with the DNS
[RFC 1034, RFC 1035]. The data shown in our examples is for
pedagogical use and does not necessarily reflect the real Internet.
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2. RDATA Format
MSB LSB
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
0| VERSION | SIZE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
2| HORIZ PRE | VERT PRE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
2| LATITUDE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
4| LATITUDE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
6| LONGITUDE LATITUDE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
8| LONGITUDE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
10| ALTITUDE LONGITUDE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
12| ALTITUDE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
14| ALTITUDE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
(octet)
where:
VERSION Version number of the representation. This must be zero.
Implementations are required to check this field and make
no assumptions about the format of unrecognized versions.
SIZE The size of the described entity, in log10(meters), centimeters, expressed
as a 4-bit integer, pair of four-bit unsigned integers, each ranging from
zero to nine, with 2^3 the most significant four bits
representing 0 the base and
lower values the second number representing negative numbers. For hosts,
this will often
the power of ten by which to multiply the base. This
allows sizes from 0e0 (<1cm) to 9e9 (90,000km) to be zero (i.e. 1m). Larger entities,
expressed. This representation was chosen such
as multinational companies' domains, will use larger
values. The largest possible value is 7 and that the
hexadecimal representation can be read by eye; 0xAB = AeB.
Since 20000000m (represented by the smallest
possible value 0x29) is -7. A value greater
than the equatorial diameter of all zero the WGS 84 ellipsoid
(12756274m), it is prohibited. therefore suitable for use as a
"worldwide" size.
HORIZ PRE The horizontal precision of the data, in log10(meters), centimeters,
expressed as a 4-bit integer, with 2^3 representing 0 and
lower values representing negative numbers. for SIZE. This is treated as an "accurate to
within N meters" centimeters" value. For
example, if the latitude and longitude have been determined
using differential GPS, this value would be 0 (i.e. 1m).
If survey maps and building blueprints are used, the value
might be 1 (i.e. 10m) or 2 (100m). If standard values for
a large area are used, the value could be as high as 6
(100km). The largest possible value is 7 and the smallest
possible value is -7. A value of all zero is prohibited.
VERT PRE The vertical precision of the point described by the
(LATITUDE, LONGITUDE, ALTITUDE) tuple, data, in log10(meters),
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expressed as a 4-bit integer, with 2^3 representing 0 and
lower values representing negative numbers. for SIZE. This is treated as an "accurate to
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within N meters" centimeters" value. The
largest possible value is 7 and the smallest possible value
is -7. A value of all zero is prohibited.
LATITUDE The latitude of the center of the sphere described by the
SIZE field, expressed as a 32-bit integer, most significant
octet first (network standard byte order), in thousandsth
of a second of arc. 2^31 represents the equator; numbers
above that are north latitude.
LONGITUDE The longitude of the center of the sphere described by the
SIZE field, expressed as a 32-bit integer, most significant
octet first (network standard byte order), in thousandths
of a second of arc, rounded away from the prime meridian.
2^31 represents the prime meridian; numbers above that are
east longitude.
ALTITUDE The altitude of the center of the sphere described by the
SIZE field, expressed as a 32-bit integer, most significant
octet first (network standard byte order), in centimeters,
from a base of 100,000m below the [WGS 84] reference
spheroid used by GPS (semimajor axis a=6378137.0,
reciprocal flattening rf=298.257223563).
3. Master File Format
The LOC record is expressed in a master file in the following format:
<owner> <TTL> <class> LOC ( d1 [m1 [s1]] {"N"|"S"} d2 [m2 [s2]]
{"E"|"W"} alt["m"] [siz["m"] [hp["m"]
[vp["m"]]]] )
(The parentheses are used for multi-line data as specified in [RFC
1035] section 5.1.)
where:
d1: [0 .. 90] (degrees latitude)
d2: [0 .. 180] (degrees longitude)
m1, m2: [0 .. 59] (minutes latitude/longitude)
s1, s2: [0 .. 59.999] (seconds latitude/longitude)
alt: [-100000.00 .. 42939672.96] BY .1 .01 (altitude in
meters)
siz, hp, vp: "0.0000001" | "0.000001" | "0.00001" | "0.0001" |
"0.001" | "0.01" | "0.1" | "1" | "10" | "100" |
"1000" | "10000" | "100000" | "1000000" |
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"10000000" [0 .. 90000000.00] (size/precision in meters)
If omitted, minutes and seconds default to zero, size defaults to 1m,
horizontal precision defaults to 10000m, and vertical precision
defaults to 10m. These defaults are chosen to represent typical
ZIP/postal code area sizes, since it is often easy to find
approximate geographical location by ZIP/postal code.
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4. Application use of the LOC RR
4.1 Suggested Uses
Some uses for the LOC RR have already been suggested, including the
USENET backbone flow maps, a "visual traceroute" application showing
the geographical path of an IP packet, and network management
applications that could use LOC RRs to generate a map of hosts and
routers being managed.
4.2 Search Algorithms
This section specifies how to use the DNS to translate domain names
and/or IP addresses into location information.
If an application wishes to have a "fallback" behavior, displaying a
less precise or larger area when a host does not have an associated
LOC RR, it MAY support use of the algorithm in section 4.2.3, as
noted in sections 4.2.1 and 4.2.2. If fallback is desired, this
behaviour is the RECOMMENDED default, but in some cases it may need
to be modified based on the specific requirements of the application
involved.
This search algorithm is designed to allow network administrators to
specify the location of a network or subnet without requiring LOC RR
data for each individual host. For example, a computer lab with 24
workstations, all of which are on the same subnet and in basically
the same location, would only need a LOC RR for the subnet.
(However, if the file server's location has been more precisely
measured, a separate LOC RR for it can be placed in the DNS.)
4.2.1 Searching by Name
If the application is beginning with a name, rather than an IP
address (as the USENET backbone flow maps do), it MUST check for a
LOC RR associated with that name. (CNAME records should be followed
as for any other RR type.)
If there is no LOC RR for that name, all A records (if any)
associated with the name MAY be checked for network (or subnet) LOC
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RRs using the "Searching by Network or Subnet" algorithm (4.2.3). If
multiple A records exist and have associated network or subnet LOC
RRs, the application may choose to use any, some, or all of the LOC
RRs found, possibly in combination. It is suggested that multi-homed
hosts have LOC RRs for their name in the DNS to avoid any ambiguity
in these cases.
Note that domain names that do not have associated A records must
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have a LOC RR associated with their name in order for location
information to be accessible.
4.2.2 Searching by Address
If the application is beginning with an IP address (as a "visual
traceroute" application might be) it MUST first map the address to a
name using the IN-ADDR.ARPA namespace (see [RFC 1034], section
5.2.1), then check for a LOC RR associated with that name.
If there is no LOC RR for the name, the address MAY be checked for
network (or subnet) LOC RRs using the "Searching by Network or
Subnet" algorithm (4.2.3).
4.2.3 Searching by Network or Subnet
Even if a host's name does not have any associated LOC RRs, the
network(s) or subnet(s) it is on may. If the application wishes to
search for such less specific data, the following algorithm SHOULD be
followed to find a network or subnet LOC RR associated with the IP
address. This algorithm is adapted slightly from that specified in
[RFC 1101], sections 4.3 and 4.4.
Since subnet LOC RRs are (if present) more specific than network LOC
RRs, it is best to use them if available. In order to do so, we
build a stack of network and subnet names found while performing the
[RFC 1101] search, then work our way down the stack until a LOC RR is
found.
1. create a host-zero address using the network portion of the IP
address (one, two, or three bytes for class A, B, or C networks,
respectively). For example, for the host 128.9.2.17, on the class
B network 128.9, this would result in the address "128.9.0.0".
2. Reverse the octets, suffix IN-ADDR.ARPA, and query for PTR and A
records. Retrieve:
0.0.9.128.IN-ADDR.ARPA. PTR isi-net.isi.edu.
A 255.255.255.0
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Push the name "isi-net.isi.edu" onto the stack of names to be
searched for LOC RRs later.
3. Since an A RR was found, repeat using mask from RR
(255.255.255.0), constructing a query for 0.2.9.128.IN-ADDR.ARPA.
Retrieve:
0.2.9.128.IN-ADDR.ARPA. PTR div2-subnet.isi.edu.
A 255.255.255.240
Push the
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A 255.255.255.240
Push the name "div2-subnet.isi.edu" onto the stack of names to be
searched for LOC RRs later.
4. Since another A RR was found, repeat using mask 255.255.255.240
(x'FFFFFFF0'), constructing a query for 16.2.9.128.IN-ADDR.ARPA.
Retrieve:
16.2.9.128.IN-ADDR.ARPA. PTR inc-subsubnet.isi.edu.
Push the name "inc-subsubnet.isi.edu" onto the stack of names to
be searched for LOC RRs later.
5. Since no A RR is present at 16.2.9.128.IN-ADDR.ARPA., there are no
more subnet levels to search. We now pop the top name from the
stack and check for an associated LOC RR. Repeat until a LOC RR
is found.
In this case, assume that inc-subsubnet.isi.edu does not have an
associated LOC RR, but that div2-subnet.isi.edu does. We will
then use div2-subnet.isi.edu's LOC RR as an approximation of this
host's location. (Note that even if isi-net.isi.edu has a LOC RR,
it will not be used if a subnet also has a LOC RR.)
4.3 Applicability to non-IN Classes and non-IP Addresses
The LOC record is defined for all RR classes, and may be used with
non-IN classes such as HS and CH. The semantics of such use are not
defined by this memo.
The search algorithm in section 4.2.3 may be adapted to other
addressing schemes by extending [RFC 1101]'s encoding of network
names to cover those schemes. Such extensions are not defined by
this memo.
5. References
[RFC 1034] Mockapetris, P., "Domain Names - Concepts and Facilities",
STD 13, RFC 1034, USC/Information Sciences Institute,
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November 1987.
[RFC 1035] Mockapetris, P., "Domain Names - Implementation and
Specification", STD 13, RFC 1035, USC/Information Sciences
Institute, November 1987.
[RFC 1101] Mockapetris, P., "DNS Encoding of Network Names and Other
Types", RFC 1101, USC/Information Sciences Institute,
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April 1989.
[WGS 84] United States Department of Defense; DoD WGS-1984 - Its
Definition and Relationships with Local Geodetic Systems;
Washington, D.C.; 1985; Report AD-A188 815 DMA; 6127; 7-
R-138-R; CV, KV;
6. Security Considerations
High-precision LOC RR information could be used to help plan a
penetration of physical security, leading to potential denial-of-
machine attacks. To avoid any appearance of suggesting this method
to potential attackers, we declined the opportunity to name this RR
"ICBM".
7. Authors' Addresses
The authors as a group can be reached as <loc@pipex.net>.
Christopher Davis
Kapor Enterprises, Inc.
238 Main Street, Suite 400
Cambridge, MA 02142
Phone: +1 617 576 4532
Email: ckd@kei.com
Paul Vixie
Vixie Enterprises
Star Route Box 159A
Woodside, CA 94062
Phone: +1 415 747 0204
Email: paul@vix.com
Tim Goodwin
Public IP Exchange Ltd (PIPEX)
216 The Science Park
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Cambridge CB4 4WA
UK
Phone: +44 1223 250250
Email: tim@pipex.net
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Ian Dickinson
Computing Services
University of Warwick
Coventry CV4 7AL
UK
Phone: +44 1203 524217
Email: cudep@csv.warwick.ac.uk
Appendix A: Sample Conversion Routines
These routines are the ones used in BIND 4.9.3 for conversion between
zone file and RDATA formats.
/*
* loc_rr.c. includes routines to convert between on-the-wire RR format
* and zone file format.
* Does not contain conversion to/from decimal
* degrees; divide or multiply
* by 60*60*1000 for that.
*/
#include <stdlib.h> /* abort() */
#include <sys/param.h>
#include <netinet/in.h> /* ntohl/htonl */
#include <arpa/nameser.h> /* for PUTLONG, bit types if needed */
#include "../conf/portability.h"
/* "signed" version of ntohl. host 0 = net (1<<31) */
static int32_t
ntohls(x)
u_int32_t x;
{
return (ntohl(x) - (1<<31));
}
/* "signed" version of htonl. host 0 unsigned int poweroften[10] = net (1<<31) */
static u_int32_t
htonls(x)
int32_t x;
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{
return (htonl(x) + (1<<31));
} {1, 10, 100, 1000, 10000, 100000,
1000000,10000000,100000000,1000000000};
/* takes a log10 precision an XeY precision/size value, returns a string representation. */
static const char *
precision2string(precval)
int8_t precval;
{
switch (precval)
precsize_ntoa(prec)
u_int8_t prec;
{
case -7:
return ("0.0000001");
case -6:
return ("0.000001");
case -5:
return ("0.00001");
case -4:
return ("0.0001");
case -3:
return ("0.001");
case -2:
return ("0.01");
case -1:
return ("0.1");
case 0:
return ("1");
case 1:
return ("10");
case 2:
return ("100");
case 3:
return ("1000");
case 4:
return ("10000");
case 5:
return ("100000");
case 6:
return ("1000000");
case 7:
return ("10000000");
default:
static char retbuf[sizeof("90000000.00")];
unsigned long val;
int mantissa, exponent;
mantissa = ((prec >> 4) & 0x0f) % 10;
exponent = ((prec >> 0) & 0x0f) % 10;
val = mantissa * poweroften[exponent];
(void) sprintf(retbuf,"%d.%.2d", val/100, val%100);
return ("1"); /* XXX error checking? */
}
/* NOTREACHED */
abort(); (retbuf);
}
/* converts lat/lon ascii size/precision X * 10**Y(cm) to unsigned encoded 32-bit number. 0xXY. moves pointer. */
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static u_int32_t
latlon2ul(latlonstrptr) u_int8_t
precsize_aton(strptr)
char **latlonstrptr; **strptr;
{
register char *cp;
u_int32_t retval;
unsigned int deg = 0, min mval = 0, secs cmval = 0, secsfrac 0;
u_int8_t retval = 0;
register char *cp;
register int exponent;
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register int mantissa;
cp = *latlonstrptr; *strptr;
while (isdigit(*cp))
deg
mval = deg mval * 10 + (*cp++ - '0');
while (isspace(*cp))
if (*cp == '.') { /* centimeters */
cp++;
if (!(isdigit(*cp)))
goto fndhemi;
while (isdigit(*cp))
min {
cmval = min * 10 + (*cp++ - '0');
while (isspace(*cp))
cp++; '0') * 10;
if (isdigit(*cp)) {
cmval += (*cp++ - '0');
}
}
}
cmval = (mval * 100) + cmval;
for (exponent = 0; exponent < 9; exponent++)
if (cmval < poweroften[exponent+1])
break;
mantissa = cmval / poweroften[exponent];
if (mantissa > 9)
mantissa = 9;
retval = (mantissa << 4) | exponent;
*strptr = cp;
return (retval);
}
/* converts ascii lat/lon to unsigned encoded 32-bit number. moves pointer. */
static u_int32_t
latlon2ul(latlonstrptr,which)
char **latlonstrptr;
int *which;
{
register char *cp;
u_int32_t retval;
int deg = 0, min = 0, secs = 0, secsfrac = 0;
cp = *latlonstrptr;
while (isdigit(*cp))
deg = deg * 10 + (*cp++ - '0');
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while (isspace(*cp))
cp++;
if (!(isdigit(*cp)))
goto fndhemi;
while (isdigit(*cp))
min = min * 10 + (*cp++ - '0');
while (isspace(*cp))
cp++;
if (!(isdigit(*cp)))
goto fndhemi;
while (isdigit(*cp))
secs = secs * 10 + (*cp++ - '0');
if (*cp == '.') { /* decimal seconds */
cp++;
if (isdigit(*cp)) {
secsfrac = (*cp++ - '0') * 100;
if (isdigit(*cp)) {
secsfrac += (*cp++ - '0') * 10;
if (isdigit(*cp)) {
secsfrac += (*cp++ - '0');
}
}
}
}
while (!isspace(*cp)) /* if any trailing garbage */
cp++;
while (isspace(*cp))
cp++;
fndhemi:
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switch (*cp) {
case 'N': case 'n':
case 'E': case 'e':
retval = (1<<31)
+ (((((deg * 60) + min) * 60) + secs) * 1000)
+ secsfrac;
break;
case 'S': case 's':
case 'W': case 'w':
retval = (1<<31)
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- (((((deg * 60) + min) * 60) + secs) * 1000)
- secsfrac); secsfrac;
break;
default:
retval = 0; /* invalid value -- indicates error */
break;
}
switch (*cp) {
case 'N': case 'n':
case 'S': case 's':
*which = 1; /* latitude */
break;
case 'E': case 'e':
case 'W': case 'w':
*which = 2; /* longitude */
break;
default:
*which = 0; /* XXX error checking? */
break;
}
cp++; /* skip the hemisphere */
while (!isspace(*cp)) /* if any trailing garbage */
cp++;
while (isspace(*cp)) /* move to next field */
cp++;
*latlonstrptr = cp;
return (retval);
}
/* converts a zone file representation in a string to an RDATA on-the-wire
* representation. */
u_int
u_int32_t
loc_aton(ascii, binary)
const char *ascii;
u_char *binary;
{
const char *cp,*maxcp; *cp, *maxcp;
u_char *bcp;
u_int32_t latit = 0, longit = 0, alt = 0;
u_int32_t lltemp1 = 0, lltemp2 = 0;
int altmeters = 0, altfrac = 0, altsign = 1;
int
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u_int8_t hp = 4; 0x16; /* default = 10000m or 1e6 cm = 10000.00m = 10km */
int
u_int8_t vp = 1; 0x13; /* default = 10m 1e3 cm = 10.00m */
int
u_int8_t siz = 0; 0x12; /* default = 1m 1e2 cm = 1.00m */
int which1 = 0, which2 = 0;
cp = ascii;
maxcp = cp + strlen(ascii);
lltemp1 = latlon2ul(&cp, &which1);
lltemp2 = latlon2ul(&cp, &which2);
switch (which1 + which2) {
case 3: /* 1 + 2, the only valid combination */
if ((which1 == 1) && (which2 == 2)) { /* normal case */
latit = latlon2ul(&cp);
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longit = latlon2ul(&cp); lltemp2;
} else if ((which1 == 2) && (which2 == 1)) { /* reversed */
longit = lltemp1;
latit = lltemp2;
} else { /* some kind of brokenness */
return 0;
}
break;
default: /* we didn't get one of each */
return 0;
}
/* altitude */
if (*cp == '-') {
altsign = -1;
cp++;
}
if (*cp == '+')
cp++;
while (isdigit(*cp))
altmeters = altmeters * 10 + (*cp++ - '0');
if (*cp == '.') { /* decimal meters */
cp++;
if (isdigit(*cp)) {
altfrac = (*cp++ - '0') * 10;
if (isdigit(*cp)) {
altfrac += (*cp++ - '0');
}
}
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}
alt = (10000000 + (altsign * (altmeters * 100 + altfrac)));
while (!isspace(*cp) && (cp < maxcp)) /* if trailing garbage or m */
cp++;
while (isspace(*cp) || (*cp == 'm') || (*cp == 'M')) && (cp < maxcp))
cp++;
if (cp >= maxcp)
goto defaults;
siz = 0;
/* get log10s for hp, vp, siz */ precsize_aton(&cp);
while (!isspace(*cp) && (cp < maxcp)) /* size */ if (*cp == '1') { /* positive trailing garbage or 0 log */
for (cp++; *cp == '0'; cp++)
siz++;
} else if (*cp == '0') { /* negative log m */
for (cp++; *cp != '1'; cp++)
siz--;
}
cp++;
while (isspace(*cp) || *cp == 'm' || *cp == 'M')
Davis, Vixie, Goodwin & Dickinson [Page 12]
Expires 1994-05-25 draft-davis-dns-loc-00.txt November 1994 && (cp < maxcp))
cp++;
if (cp >= maxcp)
goto defaults;
hp = 0; precsize_aton(&cp);
while (!isspace(*cp) && (cp < maxcp)) /* horiz precision */ if (*cp == '1') { /* positive trailing garbage or 0 log */
for (cp++; *cp == '0'; cp++)
hp++;
} else if (*cp == '0') { /* negative log m */
for (cp++; *cp != '1'; cp++)
hp--;
}
cp++;
while (isspace(*cp) || *cp == 'm' || *cp == 'M') && (cp < maxcp))
cp++;
if (cp >= maxcp)
goto defaults;
vp = 0;
/* vertical precision */
if (*cp == '1') { /* positive or 0 log */
for (cp++; *cp == '0'; cp++)
vp++;
} else if (*cp == '0') { /* negative log */
for (cp++; *cp != '1'; cp++)
vp--;
} precsize_aton(&cp);
defaults:
if ((hp > 7) || (hp < -7))
return (0);
if ((vp > 7) || (vp < -7))
return (0);
if ((siz > 7) || (siz < -7))
return (0);
/* convert hp/vp/siz sign bits as with lat/long */
hp += 8;
Davis, Vixie, Goodwin & Dickinson [Page 13]
Expires 1994-05-25 draft-davis-dns-loc-00.txt November 1994
vp += 8;
siz += 8;
bcp = binary;
*bcp++ = (u_int8_t) 0; /* version byte */
*bcp++ = siz;
*bcp++ = (u_int8_t) ((hp << 4) + vp); hp;
*bcp++ = vp;
PUTLONG(latit,bcp);
PUTLONG(longit,bcp);
PUTLONG(alt,bcp);
Davis, Vixie, Goodwin & Dickinson [Page 13]
Expires 1995-09-24 draft-davis-dns-loc-01.txt March 1995
return (14); (16); /* size of RR in octets */
}
/* takes an on-the-wire LOC RR and prints it in zone file (human readable)
format. */
char *
loc_ntoa(binary,ascii)
const u_char *binary;
char *ascii;
{
char tmpbuf[255*3];
register char *cp;
register const u_char *rcp;
int latdeg, latmin, latsec, latsecfrac;
int longdeg, longmin, longsec, longsecfrac;
char northsouth, eastwest;
int altmeters, altfrac; altfrac, altsign;
const int referencealt = 100000 * 100;
int32_t latval, longval, altval;
u_int32_t templ;
char
u_int8_t sizeval, hpval, vpval, versionval, tempc; versionval;
char *sizestr, *hpstr, *vpstr;
rcp = binary;
if (ascii)
cp = ascii;
else {
ascii = tmpbuf;
cp = tmpbuf;
}
tempc = *rcp++;
versionval = tempc & 0xF0;
sizeval = (tempc & 0x0F) - 8;
Davis, Vixie, Goodwin & Dickinson [Page 14]
Expires 1994-05-25 draft-davis-dns-loc-00.txt November 1994 *rcp++;
if (versionval) {
sprintf(cp,"; error: unknown LOC RR version");
return (cp);
}
tempc
sizeval = *rcp++;
hpval = ((tempc & 0xF0) >> 4) - 8; *rcp++;
vpval = (tempc *rcp++;
Davis, Vixie, Goodwin & 0x0F) - 8; Dickinson [Page 14]
Expires 1995-09-24 draft-davis-dns-loc-01.txt March 1995
GETLONG(templ,rcp);
latval = ntohls(templ); (templ - (1<<31));
GETLONG(templ,rcp);
longval = ntohls(templ); (templ - (1<<31));
GETLONG(templ,rcp);
if (templ < referencealt) { /* below WGS 84 spheroid */
altval = ntohl(templ) referencealt - 10000000; /* XXX might need long long */ templ;
altsign = -1;
} else {
altval = templ - referencealt;
altsign = 1;
}
if (latval < 0) {
northsouth = 'S';
latval = -latval;
}
else
northsouth = 'N';
latsecfrac = latval % 1000;
latval = latval / 1000;
latsec = latval % 60;
latval = latval / 60;
latmin = latval % 60;
latval = latval / 60;
latdeg = latval;
if (longval < 0) {
eastwest = 'W';
longval = -longval;
}
else
eastwest = 'E';
longsecfrac = longval % 1000;
longval = longval / 1000;
longsec = longval % 60;
longval = longval / 60;
longmin = longval % 60;
longval = longval / 60;
longdeg = longval;
Davis, Vixie, Goodwin & Dickinson [Page 15]
Expires 1994-05-25 draft-davis-dns-loc-00.txt November 1994
altfrac = altval % 100;
altmeters = altval (altval / 100; /* XXX might truncate wrong way if neg? */ 100) * altsign;
Davis, Vixie, Goodwin & Dickinson [Page 15]
Expires 1995-09-24 draft-davis-dns-loc-01.txt March 1995
sizestr = strdup(precision2string(sizeval)); savestr(precsize_ntoa(sizeval));
hpstr = strdup(precision2string(hpval)); savestr(precsize_ntoa(hpval));
vpstr = strdup(precision2string(vpval)); savestr(precsize_ntoa(vpval));
sprintf(cp,
"%d %.2d %.2d.%.3d %c %d %.2d %.2d.%.3d %c %d.%dm %d.%.2dm %sm %sm %sm",
latdeg, latmin, latsec, latsecfrac, northsouth,
longdeg, longmin, longsec, longsecfrac, eastwest,
altmeters, altfrac, sizestr, hpstr, vpstr);
free(sizestr);
free(hpstr);
free(vpstr);
return (cp);
}
Davis, Vixie, Goodwin & Dickinson [Page 16]
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