On Mon, Sep 05, 2005 at 08:10:16PM +0100, Patrick Welche wrote:
> On Mon, Sep 05, 2005 at 03:02:55PM -0400, Tom Lane wrote:
> > Patrick Welche <[EMAIL PROTECTED]> writes:
> > > * Allow INET + INT4 to increment the host part of the address, or
> > > throw an error on overflow
> >
> > > I think that the naively coded function attached does what is needed,
> > > e.g.,
> >
> > What happened to the IPv6 case?
>
> My take on the thread is that the IPv6 case doesn't make sense, and the
> int8 part was dropped from the TODO.
>
> > Also, I think you need to reject CIDR inputs.
>
> OK
Now with:
test=# select '192.168.0.0/24'::inet + 1;
ERROR: Trying to increment a network (192.168.0.0/24) rather than a host
test=# select '192.168.0.1/24'::inet + -1;
ERROR: Increment returns a network (192.168.0.0/24) rather than a host
Cheers,
Patrick
/* From the TODO:
* Allow INET + INT4 to increment the host part of the address, or
* throw an error on overflow
*/
#include "postgres.h"
#include <sys/socket.h>
#include "fmgr.h"
#include "utils/inet.h"
PG_FUNCTION_INFO_V1(inet_inc);
Datum
inet_inc(PG_FUNCTION_ARGS)
{
inet *in = PG_GETARG_INET_P(0), *out;
int32 inc = PG_GETARG_INT32(1);
inet_struct *src, *dst;
uint32 netmask, host, newhost;
int i;
src = (inet_struct *)VARDATA(in);
if (src->family != PGSQL_AF_INET)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Function \"inet_inc\" only supports AF_INET "
"addresses")));
/* avoid int32 overflow when bits == 0 */
netmask = (src->bits == 0) ? 0 : (~((1 << (32 - src->bits)) - 1));
/* if (inc doesn't fit in src->bits) overflow */
if ((abs(inc) & ~netmask) != abs(inc))
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("Increment (%d) too big for network (/%d)",
inc,
src->bits)));
/* can do this with htonl/ntohl */
host = 0;
for (i=0; i<4; ++i)
host |= src->ipaddr[i] << (8 * (3-i));
if ((host & ~netmask) == 0)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("Trying to increment a network (%d.%d.%d.%d/%d)
rather "
"than a host", src->ipaddr[0], src->ipaddr[1],
src->ipaddr[2], src->ipaddr[3],
src->bits)));
newhost = host + inc;
if (((host & netmask) != (newhost & netmask))
|| (inc>0 && newhost<host)
|| (inc<0 && newhost>host))
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("Increment (%d) takes address (%d.%d.%d.%d) out
of its "
"network (/%d)", inc,
src->ipaddr[0], src->ipaddr[1], src->ipaddr[2],
src->ipaddr[3], src->bits)));
out = (inet *)palloc0(VARHDRSZ + sizeof(inet_struct));
dst = (inet_struct *)VARDATA(out);
dst->family = src->family;
dst->bits = src->bits;
dst->type = src->type;
for (i=0; i<4; ++i)
dst->ipaddr[i] = (newhost >> (8 * (3-i))) & 0xff;
for (i=4; i<16; ++i)
dst->ipaddr[i] = 0;
if ((inc < 0) && (newhost & ~netmask) == 0)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("Increment returns a network (%d.%d.%d.%d/%d)
rather "
"than a host", dst->ipaddr[0], dst->ipaddr[1],
dst->ipaddr[2], dst->ipaddr[3],
dst->bits)));
VARATT_SIZEP(out) = VARHDRSZ + sizeof(dst->family) + sizeof(dst->bits)
+ sizeof(dst->type) + 4;
PG_RETURN_INET_P(out);
}
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