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Diffstat (limited to '')
| -rw-r--r-- | lib/lwres/lwres_gnba.c | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/lib/lwres/lwres_gnba.c b/lib/lwres/lwres_gnba.c new file mode 100644 index 0000000..d242f5c --- /dev/null +++ b/lib/lwres/lwres_gnba.c @@ -0,0 +1,410 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +/* $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 { + uint32_t flags; + lwres_addr_t addr; +} lwres_gnbarequest_t; + +typedef struct { + uint32_t flags; + uint16_t naliases; + char *realname; + char **aliases; + uint16_t realnamelen; + 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 <inttypes.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, (unsigned int)buflen); + + pkt->length = (uint32_t)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; + 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, (unsigned int)buflen); + + pkt->length = (uint32_t)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; + uint32_t flags; + 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(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(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(uint16_t) * gnba->naliases); + } + if (gnba->base != NULL) + CTXFREE(gnba->base, gnba->baselen); + CTXFREE(gnba, sizeof(lwres_gnbaresponse_t)); +} |