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