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| Current File : //usr/src/contrib/bind9/lib/lwres/lwres_gnba.c |
/*
* Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 2000-2002 Internet Software Consortium.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: lwres_gnba.c,v 1.28 2007/09/24 17:18:25 each Exp $ */
/*! \file lwres_gnba.c
These are low-level routines for creating and parsing lightweight
resolver address-to-name lookup request and response messages.
There are four main functions for the getnamebyaddr opcode. One
render function converts a getnamebyaddr request structure --
lwres_gnbarequest_t -- to the lightweight resolver's canonical
format. It is complemented by a parse function that converts a
packet in this canonical format to a getnamebyaddr request
structure. Another render function converts the getnamebyaddr
response structure -- lwres_gnbaresponse_t to the canonical format.
This is complemented by a parse function which converts a packet in
canonical format to a getnamebyaddr response structure.
These structures are defined in \link lwres.h <lwres/lwres.h.>\endlink They are shown
below.
\code
#define LWRES_OPCODE_GETNAMEBYADDR 0x00010002U
typedef struct {
lwres_uint32_t flags;
lwres_addr_t addr;
} lwres_gnbarequest_t;
typedef struct {
lwres_uint32_t flags;
lwres_uint16_t naliases;
char *realname;
char **aliases;
lwres_uint16_t realnamelen;
lwres_uint16_t *aliaslen;
void *base;
size_t baselen;
} lwres_gnbaresponse_t;
\endcode
lwres_gnbarequest_render() uses resolver context ctx to convert
getnamebyaddr request structure req to canonical format. The packet
header structure pkt is initialised and transferred to buffer b.
The contents of *req are then appended to the buffer in canonical
format. lwres_gnbaresponse_render() performs the same task, except
it converts a getnamebyaddr response structure lwres_gnbaresponse_t
to the lightweight resolver's canonical format.
lwres_gnbarequest_parse() uses context ctx to convert the contents
of packet pkt to a lwres_gnbarequest_t structure. Buffer b provides
space to be used for storing this structure. When the function
succeeds, the resulting lwres_gnbarequest_t is made available
through *structp. lwres_gnbaresponse_parse() offers the same
semantics as lwres_gnbarequest_parse() except it yields a
lwres_gnbaresponse_t structure.
lwres_gnbaresponse_free() and lwres_gnbarequest_free() release the
memory in resolver context ctx that was allocated to the
lwres_gnbaresponse_t or lwres_gnbarequest_t structures referenced
via structp. Any memory associated with ancillary buffers and
strings for those structures is also discarded.
\section lwres_gbna_return Return Values
The getnamebyaddr opcode functions lwres_gnbarequest_render(),
lwres_gnbaresponse_render() lwres_gnbarequest_parse() and
lwres_gnbaresponse_parse() all return #LWRES_R_SUCCESS on success.
They return #LWRES_R_NOMEMORY if memory allocation fails.
#LWRES_R_UNEXPECTEDEND is returned if the available space in the
buffer b is too small to accommodate the packet header or the
lwres_gnbarequest_t and lwres_gnbaresponse_t structures.
lwres_gnbarequest_parse() and lwres_gnbaresponse_parse() will
return #LWRES_R_UNEXPECTEDEND if the buffer is not empty after
decoding the received packet. These functions will return
#LWRES_R_FAILURE if pktflags in the packet header structure
#lwres_lwpacket_t indicate that the packet is not a response to an
earlier query.
\section lwres_gbna_see See Also
\link lwpacket.c lwres_packet\endlink
*/
#include <config.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <lwres/lwbuffer.h>
#include <lwres/lwpacket.h>
#include <lwres/lwres.h>
#include <lwres/result.h>
#include "context_p.h"
#include "assert_p.h"
/*% Uses resolver context ctx to convert getnamebyaddr request structure req to canonical format. */
lwres_result_t
lwres_gnbarequest_render(lwres_context_t *ctx, lwres_gnbarequest_t *req,
lwres_lwpacket_t *pkt, lwres_buffer_t *b)
{
unsigned char *buf;
size_t buflen;
int ret;
size_t payload_length;
REQUIRE(ctx != NULL);
REQUIRE(req != NULL);
REQUIRE(req->addr.family != 0);
REQUIRE(req->addr.length != 0);
REQUIRE(pkt != NULL);
REQUIRE(b != NULL);
payload_length = 4 + 4 + 2 + + req->addr.length;
buflen = LWRES_LWPACKET_LENGTH + payload_length;
buf = CTXMALLOC(buflen);
if (buf == NULL)
return (LWRES_R_NOMEMORY);
lwres_buffer_init(b, buf, buflen);
pkt->length = buflen;
pkt->version = LWRES_LWPACKETVERSION_0;
pkt->pktflags &= ~LWRES_LWPACKETFLAG_RESPONSE;
pkt->opcode = LWRES_OPCODE_GETNAMEBYADDR;
pkt->result = 0;
pkt->authtype = 0;
pkt->authlength = 0;
ret = lwres_lwpacket_renderheader(b, pkt);
if (ret != LWRES_R_SUCCESS) {
lwres_buffer_invalidate(b);
CTXFREE(buf, buflen);
return (ret);
}
INSIST(SPACE_OK(b, payload_length));
/*
* Put the length and the data. We know this will fit because we
* just checked for it.
*/
lwres_buffer_putuint32(b, req->flags);
lwres_buffer_putuint32(b, req->addr.family);
lwres_buffer_putuint16(b, req->addr.length);
lwres_buffer_putmem(b, (unsigned char *)req->addr.address,
req->addr.length);
INSIST(LWRES_BUFFER_AVAILABLECOUNT(b) == 0);
return (LWRES_R_SUCCESS);
}
/*% Converts a getnamebyaddr response structure lwres_gnbaresponse_t to the lightweight resolver's canonical format. */
lwres_result_t
lwres_gnbaresponse_render(lwres_context_t *ctx, lwres_gnbaresponse_t *req,
lwres_lwpacket_t *pkt, lwres_buffer_t *b)
{
unsigned char *buf;
size_t buflen;
int ret;
size_t payload_length;
lwres_uint16_t datalen;
int x;
REQUIRE(ctx != NULL);
REQUIRE(req != NULL);
REQUIRE(pkt != NULL);
REQUIRE(b != NULL);
/*
* Calculate packet size.
*/
payload_length = 4; /* flags */
payload_length += 2; /* naliases */
payload_length += 2 + req->realnamelen + 1; /* real name encoding */
for (x = 0; x < req->naliases; x++) /* each alias */
payload_length += 2 + req->aliaslen[x] + 1;
buflen = LWRES_LWPACKET_LENGTH + payload_length;
buf = CTXMALLOC(buflen);
if (buf == NULL)
return (LWRES_R_NOMEMORY);
lwres_buffer_init(b, buf, buflen);
pkt->length = buflen;
pkt->version = LWRES_LWPACKETVERSION_0;
pkt->pktflags |= LWRES_LWPACKETFLAG_RESPONSE;
pkt->opcode = LWRES_OPCODE_GETNAMEBYADDR;
pkt->authtype = 0;
pkt->authlength = 0;
ret = lwres_lwpacket_renderheader(b, pkt);
if (ret != LWRES_R_SUCCESS) {
lwres_buffer_invalidate(b);
CTXFREE(buf, buflen);
return (ret);
}
INSIST(SPACE_OK(b, payload_length));
lwres_buffer_putuint32(b, req->flags);
/* encode naliases */
lwres_buffer_putuint16(b, req->naliases);
/* encode the real name */
datalen = req->realnamelen;
lwres_buffer_putuint16(b, datalen);
lwres_buffer_putmem(b, (unsigned char *)req->realname, datalen);
lwres_buffer_putuint8(b, 0);
/* encode the aliases */
for (x = 0; x < req->naliases; x++) {
datalen = req->aliaslen[x];
lwres_buffer_putuint16(b, datalen);
lwres_buffer_putmem(b, (unsigned char *)req->aliases[x],
datalen);
lwres_buffer_putuint8(b, 0);
}
INSIST(LWRES_BUFFER_AVAILABLECOUNT(b) == 0);
return (LWRES_R_SUCCESS);
}
/*% Uses context ctx to convert the contents of packet pkt to a lwres_gnbarequest_t structure. */
lwres_result_t
lwres_gnbarequest_parse(lwres_context_t *ctx, lwres_buffer_t *b,
lwres_lwpacket_t *pkt, lwres_gnbarequest_t **structp)
{
int ret;
lwres_gnbarequest_t *gnba;
REQUIRE(ctx != NULL);
REQUIRE(pkt != NULL);
REQUIRE(b != NULL);
REQUIRE(structp != NULL && *structp == NULL);
if ((pkt->pktflags & LWRES_LWPACKETFLAG_RESPONSE) != 0)
return (LWRES_R_FAILURE);
if (!SPACE_REMAINING(b, 4))
return (LWRES_R_UNEXPECTEDEND);
gnba = CTXMALLOC(sizeof(lwres_gnbarequest_t));
if (gnba == NULL)
return (LWRES_R_NOMEMORY);
gnba->flags = lwres_buffer_getuint32(b);
ret = lwres_addr_parse(b, &gnba->addr);
if (ret != LWRES_R_SUCCESS)
goto out;
if (LWRES_BUFFER_REMAINING(b) != 0) {
ret = LWRES_R_TRAILINGDATA;
goto out;
}
*structp = gnba;
return (LWRES_R_SUCCESS);
out:
if (gnba != NULL)
lwres_gnbarequest_free(ctx, &gnba);
return (ret);
}
/*% Offers the same semantics as lwres_gnbarequest_parse() except it yields a lwres_gnbaresponse_t structure. */
lwres_result_t
lwres_gnbaresponse_parse(lwres_context_t *ctx, lwres_buffer_t *b,
lwres_lwpacket_t *pkt, lwres_gnbaresponse_t **structp)
{
int ret;
unsigned int x;
lwres_uint32_t flags;
lwres_uint16_t naliases;
lwres_gnbaresponse_t *gnba;
REQUIRE(ctx != NULL);
REQUIRE(pkt != NULL);
REQUIRE(b != NULL);
REQUIRE(structp != NULL && *structp == NULL);
gnba = NULL;
if ((pkt->pktflags & LWRES_LWPACKETFLAG_RESPONSE) == 0)
return (LWRES_R_FAILURE);
/*
* Pull off flags & naliases
*/
if (!SPACE_REMAINING(b, 4 + 2))
return (LWRES_R_UNEXPECTEDEND);
flags = lwres_buffer_getuint32(b);
naliases = lwres_buffer_getuint16(b);
gnba = CTXMALLOC(sizeof(lwres_gnbaresponse_t));
if (gnba == NULL)
return (LWRES_R_NOMEMORY);
gnba->base = NULL;
gnba->aliases = NULL;
gnba->aliaslen = NULL;
gnba->flags = flags;
gnba->naliases = naliases;
if (naliases > 0) {
gnba->aliases = CTXMALLOC(sizeof(char *) * naliases);
if (gnba->aliases == NULL) {
ret = LWRES_R_NOMEMORY;
goto out;
}
gnba->aliaslen = CTXMALLOC(sizeof(lwres_uint16_t) * naliases);
if (gnba->aliaslen == NULL) {
ret = LWRES_R_NOMEMORY;
goto out;
}
}
/*
* Now, pull off the real name.
*/
ret = lwres_string_parse(b, &gnba->realname, &gnba->realnamelen);
if (ret != LWRES_R_SUCCESS)
goto out;
/*
* Parse off the aliases.
*/
for (x = 0; x < gnba->naliases; x++) {
ret = lwres_string_parse(b, &gnba->aliases[x],
&gnba->aliaslen[x]);
if (ret != LWRES_R_SUCCESS)
goto out;
}
if (LWRES_BUFFER_REMAINING(b) != 0) {
ret = LWRES_R_TRAILINGDATA;
goto out;
}
*structp = gnba;
return (LWRES_R_SUCCESS);
out:
if (gnba != NULL) {
if (gnba->aliases != NULL)
CTXFREE(gnba->aliases, sizeof(char *) * naliases);
if (gnba->aliaslen != NULL)
CTXFREE(gnba->aliaslen,
sizeof(lwres_uint16_t) * naliases);
CTXFREE(gnba, sizeof(lwres_gnbaresponse_t));
}
return (ret);
}
/*% Release the memory in resolver context ctx that was allocated to the lwres_gnbarequest_t. */
void
lwres_gnbarequest_free(lwres_context_t *ctx, lwres_gnbarequest_t **structp)
{
lwres_gnbarequest_t *gnba;
REQUIRE(ctx != NULL);
REQUIRE(structp != NULL && *structp != NULL);
gnba = *structp;
*structp = NULL;
CTXFREE(gnba, sizeof(lwres_gnbarequest_t));
}
/*% Release the memory in resolver context ctx that was allocated to the lwres_gnbaresponse_t. */
void
lwres_gnbaresponse_free(lwres_context_t *ctx, lwres_gnbaresponse_t **structp)
{
lwres_gnbaresponse_t *gnba;
REQUIRE(ctx != NULL);
REQUIRE(structp != NULL && *structp != NULL);
gnba = *structp;
*structp = NULL;
if (gnba->naliases > 0) {
CTXFREE(gnba->aliases, sizeof(char *) * gnba->naliases);
CTXFREE(gnba->aliaslen,
sizeof(lwres_uint16_t) * gnba->naliases);
}
if (gnba->base != NULL)
CTXFREE(gnba->base, gnba->baselen);
CTXFREE(gnba, sizeof(lwres_gnbaresponse_t));
}