| /* $OpenBSD: getrrsetbyname.c,v 1.4 2001/08/16 18:16:43 ho Exp $ */ |
| |
| /* |
| * Copyright (c) 2001 Jakob Schlyter. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /* |
| * Portions Copyright (c) 1999-2001 Internet Software Consortium. |
| * |
| * Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM |
| * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL |
| * INTERNET SOFTWARE CONSORTIUM 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. |
| */ |
| |
| #include "includes.h" |
| |
| #ifndef HAVE_GETRRSETBYNAME |
| |
| #include "getrrsetbyname.h" |
| |
| #define ANSWER_BUFFER_SIZE 1024*64 |
| |
| struct dns_query { |
| char *name; |
| u_int16_t type; |
| u_int16_t class; |
| struct dns_query *next; |
| }; |
| |
| struct dns_rr { |
| char *name; |
| u_int16_t type; |
| u_int16_t class; |
| u_int16_t ttl; |
| u_int16_t size; |
| void *rdata; |
| struct dns_rr *next; |
| }; |
| |
| struct dns_response { |
| HEADER header; |
| struct dns_query *query; |
| struct dns_rr *answer; |
| struct dns_rr *authority; |
| struct dns_rr *additional; |
| }; |
| |
| static struct dns_response *parse_dns_response(const char *, int); |
| static struct dns_query *parse_dns_qsection(const char *, int, const char **, |
| int); |
| static struct dns_rr *parse_dns_rrsection(const char *, int, const char **, |
| int); |
| |
| static void free_dns_query(struct dns_query *); |
| static void free_dns_rr(struct dns_rr *); |
| static void free_dns_response(struct dns_response *); |
| |
| static int count_dns_rr(struct dns_rr *, u_int16_t, u_int16_t); |
| |
| /* |
| * Inline versions of get/put short/long. Pointer is advanced. |
| * |
| * These macros demonstrate the property of C whereby it can be |
| * portable or it can be elegant but rarely both. |
| */ |
| |
| #ifndef INT32SZ |
| # define INT32SZ 4 |
| #endif |
| #ifndef INT16SZ |
| # define INT16SZ 2 |
| #endif |
| |
| #ifndef GETSHORT |
| #define GETSHORT(s, cp) { \ |
| register u_char *t_cp = (u_char *)(cp); \ |
| (s) = ((u_int16_t)t_cp[0] << 8) \ |
| | ((u_int16_t)t_cp[1]) \ |
| ; \ |
| (cp) += INT16SZ; \ |
| } |
| #endif |
| |
| #ifndef GETLONG |
| #define GETLONG(l, cp) { \ |
| register u_char *t_cp = (u_char *)(cp); \ |
| (l) = ((u_int32_t)t_cp[0] << 24) \ |
| | ((u_int32_t)t_cp[1] << 16) \ |
| | ((u_int32_t)t_cp[2] << 8) \ |
| | ((u_int32_t)t_cp[3]) \ |
| ; \ |
| (cp) += INT32SZ; \ |
| } |
| #endif |
| |
| /* |
| * Routines to insert/extract short/long's. |
| */ |
| |
| static u_int16_t |
| _getshort(msgp) |
| register const u_char *msgp; |
| { |
| register u_int16_t u; |
| |
| GETSHORT(u, msgp); |
| return (u); |
| } |
| |
| static u_int32_t |
| _getlong(msgp) |
| register const u_char *msgp; |
| { |
| register u_int32_t u; |
| |
| GETLONG(u, msgp); |
| return (u); |
| } |
| |
| int |
| getrrsetbyname(const char *hostname, unsigned int rdclass, |
| unsigned int rdtype, unsigned int flags, |
| struct rrsetinfo **res) |
| { |
| int result; |
| struct rrsetinfo *rrset = NULL; |
| struct dns_response *response; |
| struct dns_rr *rr; |
| struct rdatainfo *rdata; |
| unsigned int length, index_ans, index_sig; |
| char answer[ANSWER_BUFFER_SIZE]; |
| |
| /* check for invalid class and type */ |
| if (rdclass > 0xffff || rdtype > 0xffff) { |
| result = ERRSET_INVAL; |
| goto fail; |
| } |
| |
| /* don't allow queries of class or type ANY */ |
| if (rdclass == 0xff || rdtype == 0xff) { |
| result = ERRSET_INVAL; |
| goto fail; |
| } |
| |
| /* don't allow flags yet, unimplemented */ |
| if (flags) { |
| result = ERRSET_INVAL; |
| goto fail; |
| } |
| |
| /* initialize resolver */ |
| if ((_res.options & RES_INIT) == 0 && res_init() == -1) { |
| result = ERRSET_FAIL; |
| goto fail; |
| } |
| |
| #ifdef DEBUG |
| _res.options |= RES_DEBUG; |
| #endif /* DEBUG */ |
| |
| #ifdef RES_USE_DNSSEC |
| /* turn on DNSSEC if EDNS0 is configured */ |
| if (_res.options & RES_USE_EDNS0) |
| _res.options |= RES_USE_DNSSEC; |
| #endif /* RES_USE_DNSEC */ |
| |
| /* make query */ |
| length = res_query(hostname, rdclass, rdtype, answer, sizeof(answer)); |
| if (length < 0) { |
| switch(h_errno) { |
| case HOST_NOT_FOUND: |
| result = ERRSET_NONAME; |
| goto fail; |
| case NO_DATA: |
| result = ERRSET_NODATA; |
| goto fail; |
| default: |
| result = ERRSET_FAIL; |
| goto fail; |
| } |
| } |
| |
| /* parse result */ |
| response = parse_dns_response(answer, length); |
| if (response == NULL) { |
| result = ERRSET_FAIL; |
| goto fail; |
| } |
| |
| if (response->header.qdcount != 1) { |
| result = ERRSET_FAIL; |
| goto fail; |
| } |
| |
| /* initialize rrset */ |
| rrset = calloc(1, sizeof(struct rrsetinfo)); |
| if (rrset == NULL) { |
| result = ERRSET_NOMEMORY; |
| goto fail; |
| } |
| rrset->rri_rdclass = response->query->class; |
| rrset->rri_rdtype = response->query->type; |
| rrset->rri_ttl = response->answer->ttl; |
| rrset->rri_nrdatas = response->header.ancount; |
| |
| /* check for authenticated data */ |
| if (response->header.ad == 1) |
| rrset->rri_flags |= RRSET_VALIDATED; |
| |
| /* copy name from answer section */ |
| length = strlen(response->answer->name); |
| rrset->rri_name = malloc(length + 1); |
| if (rrset->rri_name == NULL) { |
| result = ERRSET_NOMEMORY; |
| goto fail; |
| } |
| strlcpy(rrset->rri_name, response->answer->name, length + 1); |
| |
| /* count answers */ |
| rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass, |
| rrset->rri_rdtype); |
| rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass, |
| T_SIG); |
| |
| /* allocate memory for answers */ |
| rrset->rri_rdatas = calloc(rrset->rri_nrdatas, |
| sizeof(struct rdatainfo)); |
| if (rrset->rri_rdatas == NULL) { |
| result = ERRSET_NOMEMORY; |
| goto fail; |
| } |
| |
| /* allocate memory for signatures */ |
| rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo)); |
| if (rrset->rri_sigs == NULL) { |
| result = ERRSET_NOMEMORY; |
| goto fail; |
| } |
| |
| /* copy answers & signatures */ |
| for (rr = response->answer, index_ans = 0, index_sig = 0; |
| rr; rr = rr->next) { |
| |
| rdata = NULL; |
| |
| if (rr->class == rrset->rri_rdclass && |
| rr->type == rrset->rri_rdtype) |
| rdata = &rrset->rri_rdatas[index_ans++]; |
| |
| if (rr->class == rrset->rri_rdclass && |
| rr->type == T_SIG) |
| rdata = &rrset->rri_sigs[index_sig++]; |
| |
| if (rdata) { |
| rdata->rdi_length = rr->size; |
| rdata->rdi_data = malloc(rr->size); |
| |
| if (rdata->rdi_data == NULL) { |
| result = ERRSET_NOMEMORY; |
| goto fail; |
| } |
| memcpy(rdata->rdi_data, rr->rdata, rr->size); |
| } |
| } |
| |
| *res = rrset; |
| return (ERRSET_SUCCESS); |
| |
| fail: |
| if (rrset != NULL) |
| freerrset(rrset); |
| return (result); |
| } |
| |
| void |
| freerrset(struct rrsetinfo *rrset) |
| { |
| u_int16_t i; |
| |
| if (rrset == NULL) |
| return; |
| |
| if (rrset->rri_rdatas) { |
| for (i = 0; i < rrset->rri_nrdatas; i++) { |
| if (rrset->rri_rdatas[i].rdi_data == NULL) |
| break; |
| free(rrset->rri_rdatas[i].rdi_data); |
| } |
| free(rrset->rri_rdatas); |
| } |
| |
| if (rrset->rri_sigs) { |
| for (i = 0; i < rrset->rri_nsigs; i++) { |
| if (rrset->rri_sigs[i].rdi_data == NULL) |
| break; |
| free(rrset->rri_sigs[i].rdi_data); |
| } |
| free(rrset->rri_sigs); |
| } |
| |
| if (rrset->rri_name) |
| free(rrset->rri_name); |
| free(rrset); |
| } |
| |
| /* |
| * DNS response parsing routines |
| */ |
| static struct dns_response * |
| parse_dns_response(const char *answer, int size) |
| { |
| struct dns_response *resp; |
| const char *cp; |
| |
| /* allocate memory for the response */ |
| resp = calloc(1, sizeof(*resp)); |
| if (resp == NULL) |
| return (NULL); |
| |
| /* initialize current pointer */ |
| cp = answer; |
| |
| /* copy header */ |
| memcpy(&resp->header, cp, HFIXEDSZ); |
| cp += HFIXEDSZ; |
| |
| /* fix header byte order */ |
| resp->header.qdcount = ntohs(resp->header.qdcount); |
| resp->header.ancount = ntohs(resp->header.ancount); |
| resp->header.nscount = ntohs(resp->header.nscount); |
| resp->header.arcount = ntohs(resp->header.arcount); |
| |
| /* there must be at least one query */ |
| if (resp->header.qdcount < 1) { |
| free_dns_response(resp); |
| return (NULL); |
| } |
| |
| /* parse query section */ |
| resp->query = parse_dns_qsection(answer, size, &cp, |
| resp->header.qdcount); |
| if (resp->header.qdcount && resp->query == NULL) { |
| free_dns_response(resp); |
| return (NULL); |
| } |
| |
| /* parse answer section */ |
| resp->answer = parse_dns_rrsection(answer, size, &cp, |
| resp->header.ancount); |
| if (resp->header.ancount && resp->answer == NULL) { |
| free_dns_response(resp); |
| return (NULL); |
| } |
| |
| /* parse authority section */ |
| resp->authority = parse_dns_rrsection(answer, size, &cp, |
| resp->header.nscount); |
| if (resp->header.nscount && resp->authority == NULL) { |
| free_dns_response(resp); |
| return (NULL); |
| } |
| |
| /* parse additional section */ |
| resp->additional = parse_dns_rrsection(answer, size, &cp, |
| resp->header.arcount); |
| if (resp->header.arcount && resp->additional == NULL) { |
| free_dns_response(resp); |
| return (NULL); |
| } |
| |
| return (resp); |
| } |
| |
| static struct dns_query * |
| parse_dns_qsection(const char *answer, int size, const char **cp, int count) |
| { |
| struct dns_query *head, *curr, *prev; |
| int i, length; |
| char name[MAXDNAME]; |
| |
| for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) { |
| |
| /* allocate and initialize struct */ |
| curr = calloc(1, sizeof(struct dns_query)); |
| if (curr == NULL) { |
| free_dns_query(head); |
| return (NULL); |
| } |
| if (head == NULL) |
| head = curr; |
| if (prev != NULL) |
| prev->next = curr; |
| |
| /* name */ |
| length = dn_expand(answer, answer + size, *cp, name, |
| sizeof(name)); |
| if (length < 0) { |
| free_dns_query(head); |
| return (NULL); |
| } |
| curr->name = strdup(name); |
| if (curr->name == NULL) { |
| free_dns_query(head); |
| return (NULL); |
| } |
| *cp += length; |
| |
| /* type */ |
| curr->type = _getshort(*cp); |
| *cp += INT16SZ; |
| |
| /* class */ |
| curr->class = _getshort(*cp); |
| *cp += INT16SZ; |
| } |
| |
| return (head); |
| } |
| |
| static struct dns_rr * |
| parse_dns_rrsection(const char *answer, int size, const char **cp, int count) |
| { |
| struct dns_rr *head, *curr, *prev; |
| int i, length; |
| char name[MAXDNAME]; |
| |
| for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) { |
| |
| /* allocate and initialize struct */ |
| curr = calloc(1, sizeof(struct dns_rr)); |
| if (curr == NULL) { |
| free_dns_rr(head); |
| return (NULL); |
| } |
| if (head == NULL) |
| head = curr; |
| if (prev != NULL) |
| prev->next = curr; |
| |
| /* name */ |
| length = dn_expand(answer, answer + size, *cp, name, |
| sizeof(name)); |
| if (length < 0) { |
| free_dns_rr(head); |
| return (NULL); |
| } |
| curr->name = strdup(name); |
| if (curr->name == NULL) { |
| free_dns_rr(head); |
| return (NULL); |
| } |
| *cp += length; |
| |
| /* type */ |
| curr->type = _getshort(*cp); |
| *cp += INT16SZ; |
| |
| /* class */ |
| curr->class = _getshort(*cp); |
| *cp += INT16SZ; |
| |
| /* ttl */ |
| curr->ttl = _getlong(*cp); |
| *cp += INT32SZ; |
| |
| /* rdata size */ |
| curr->size = _getshort(*cp); |
| *cp += INT16SZ; |
| |
| /* rdata itself */ |
| curr->rdata = malloc(curr->size); |
| if (curr->rdata == NULL) { |
| free_dns_rr(head); |
| return (NULL); |
| } |
| memcpy(curr->rdata, *cp, curr->size); |
| *cp += curr->size; |
| } |
| |
| return (head); |
| } |
| |
| static void |
| free_dns_query(struct dns_query *p) |
| { |
| if (p == NULL) |
| return; |
| |
| if (p->name) |
| free(p->name); |
| free_dns_query(p->next); |
| free(p); |
| } |
| |
| static void |
| free_dns_rr(struct dns_rr *p) |
| { |
| if (p == NULL) |
| return; |
| |
| if (p->name) |
| free(p->name); |
| if (p->rdata) |
| free(p->rdata); |
| free_dns_rr(p->next); |
| free(p); |
| } |
| |
| static void |
| free_dns_response(struct dns_response *p) |
| { |
| if (p == NULL) |
| return; |
| |
| free_dns_query(p->query); |
| free_dns_rr(p->answer); |
| free_dns_rr(p->authority); |
| free_dns_rr(p->additional); |
| free(p); |
| } |
| |
| static int |
| count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type) |
| { |
| int n = 0; |
| |
| while(p) { |
| if (p->class == class && p->type == type) |
| n++; |
| p = p->next; |
| } |
| |
| return (n); |
| } |
| |
| #endif /* HAVE_GETRRSETBYNAME */ |