/* * Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC") * Copyright (C) 2000, 2001 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_noop.c,v 1.19 2007/06/19 23:47:22 tbox Exp $ */ /*! \file */ /** * These are low-level routines for creating and parsing lightweight * resolver no-op request and response messages. * * The no-op message is analogous to a ping packet: a packet is sent to * the resolver daemon and is simply echoed back. The opcode is intended * to allow a client to determine if the server is operational or not. * * There are four main functions for the no-op opcode. One render * function converts a no-op request structure -- lwres_nooprequest_t -- * to the lighweight resolver's canonical format. It is complemented by a * parse function that converts a packet in this canonical format to a * no-op request structure. Another render function converts the no-op * response structure -- lwres_noopresponse_t to the canonical format. * This is complemented by a parse function which converts a packet in * canonical format to a no-op response structure. * * These structures are defined in \link lwres.h <lwres/lwres.h.> \endlink They are shown below. * * \code * #define LWRES_OPCODE_NOOP 0x00000000U * * typedef struct { * lwres_uint16_t datalength; * unsigned char *data; * } lwres_nooprequest_t; * * typedef struct { * lwres_uint16_t datalength; * unsigned char *data; * } lwres_noopresponse_t; * \endcode * * Although the structures have different types, they are identical. This * is because the no-op opcode simply echos whatever data was sent: the * response is therefore identical to the request. * * lwres_nooprequest_render() uses resolver context ctx to convert no-op * 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_noopresponse_render() performs the same task, except it converts * a no-op response structure lwres_noopresponse_t to the lightweight * resolver's canonical format. * * lwres_nooprequest_parse() uses context ctx to convert the contents of * packet pkt to a lwres_nooprequest_t structure. Buffer b provides space * to be used for storing this structure. When the function succeeds, the * resulting lwres_nooprequest_t is made available through *structp. * lwres_noopresponse_parse() offers the same semantics as * lwres_nooprequest_parse() except it yields a lwres_noopresponse_t * structure. * * lwres_noopresponse_free() and lwres_nooprequest_free() release the * memory in resolver context ctx that was allocated to the * lwres_noopresponse_t or lwres_nooprequest_t structures referenced via * structp. * * \section lwres_noop_return Return Values * * The no-op opcode functions lwres_nooprequest_render(), * lwres_noopresponse_render() lwres_nooprequest_parse() and * lwres_noopresponse_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_nooprequest_t and lwres_noopresponse_t structures. * lwres_nooprequest_parse() and lwres_noopresponse_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_noop_see See Also * * lwpacket.c */ #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 no-op request structure req to canonical format. */ lwres_result_t lwres_nooprequest_render(lwres_context_t *ctx, lwres_nooprequest_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(pkt != NULL); REQUIRE(b != NULL); payload_length = sizeof(lwres_uint16_t) + req->datalength; 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_NOOP; 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_putuint16(b, req->datalength); lwres_buffer_putmem(b, req->data, req->datalength); INSIST(LWRES_BUFFER_AVAILABLECOUNT(b) == 0); return (LWRES_R_SUCCESS); } /*% Converts a no-op response structure lwres_noopresponse_t to the lightweight resolver's canonical format. */ lwres_result_t lwres_noopresponse_render(lwres_context_t *ctx, lwres_noopresponse_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(pkt != NULL); REQUIRE(b != NULL); payload_length = sizeof(lwres_uint16_t) + req->datalength; 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_NOOP; 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_putuint16(b, req->datalength); lwres_buffer_putmem(b, req->data, req->datalength); INSIST(LWRES_BUFFER_AVAILABLECOUNT(b) == 0); return (LWRES_R_SUCCESS); } /*% Uses context ctx to convert the contents of packet pkt to a lwres_nooprequest_t structure. */ lwres_result_t lwres_nooprequest_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_nooprequest_t **structp) { int ret; lwres_nooprequest_t *req; REQUIRE(ctx != NULL); REQUIRE(b != NULL); REQUIRE(pkt != NULL); REQUIRE(structp != NULL && *structp == NULL); if ((pkt->pktflags & LWRES_LWPACKETFLAG_RESPONSE) != 0) return (LWRES_R_FAILURE); req = CTXMALLOC(sizeof(lwres_nooprequest_t)); if (req == NULL) return (LWRES_R_NOMEMORY); if (!SPACE_REMAINING(b, sizeof(lwres_uint16_t))) { ret = LWRES_R_UNEXPECTEDEND; goto out; } req->datalength = lwres_buffer_getuint16(b); if (!SPACE_REMAINING(b, req->datalength)) { ret = LWRES_R_UNEXPECTEDEND; goto out; } req->data = b->base + b->current; lwres_buffer_forward(b, req->datalength); if (LWRES_BUFFER_REMAINING(b) != 0) { ret = LWRES_R_TRAILINGDATA; goto out; } /* success! */ *structp = req; return (LWRES_R_SUCCESS); /* Error return */ out: CTXFREE(req, sizeof(lwres_nooprequest_t)); return (ret); } /*% Offers the same semantics as lwres_nooprequest_parse() except it yields a lwres_noopresponse_t structure. */ lwres_result_t lwres_noopresponse_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_noopresponse_t **structp) { int ret; lwres_noopresponse_t *req; REQUIRE(ctx != NULL); REQUIRE(b != NULL); REQUIRE(pkt != NULL); REQUIRE(structp != NULL && *structp == NULL); if ((pkt->pktflags & LWRES_LWPACKETFLAG_RESPONSE) == 0) return (LWRES_R_FAILURE); req = CTXMALLOC(sizeof(lwres_noopresponse_t)); if (req == NULL) return (LWRES_R_NOMEMORY); if (!SPACE_REMAINING(b, sizeof(lwres_uint16_t))) { ret = LWRES_R_UNEXPECTEDEND; goto out; } req->datalength = lwres_buffer_getuint16(b); if (!SPACE_REMAINING(b, req->datalength)) { ret = LWRES_R_UNEXPECTEDEND; goto out; } req->data = b->base + b->current; lwres_buffer_forward(b, req->datalength); if (LWRES_BUFFER_REMAINING(b) != 0) { ret = LWRES_R_TRAILINGDATA; goto out; } /* success! */ *structp = req; return (LWRES_R_SUCCESS); /* Error return */ out: CTXFREE(req, sizeof(lwres_noopresponse_t)); return (ret); } /*% Release the memory in resolver context ctx. */ void lwres_noopresponse_free(lwres_context_t *ctx, lwres_noopresponse_t **structp) { lwres_noopresponse_t *noop; REQUIRE(ctx != NULL); REQUIRE(structp != NULL && *structp != NULL); noop = *structp; *structp = NULL; CTXFREE(noop, sizeof(lwres_noopresponse_t)); } /*% Release the memory in resolver context ctx. */ void lwres_nooprequest_free(lwres_context_t *ctx, lwres_nooprequest_t **structp) { lwres_nooprequest_t *noop; REQUIRE(ctx != NULL); REQUIRE(structp != NULL && *structp != NULL); noop = *structp; *structp = NULL; CTXFREE(noop, sizeof(lwres_nooprequest_t)); }