dns_util

/* * Copyright (c) 1999-2007 Apple Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ *  * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. *  * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. *  * @APPLE_LICENSE_HEADER_END@ */#include <stdio.h>#include <stdlib.h>#include <ctype.h>#include <string.h>#include <unistd.h>#include <netdb.h>#include <stdarg.h>#include <sys/stat.h>#include <sys/dir.h>#include <errno.h>#include <sys/types.h>#include <sys/socket.h>#include <ifaddrs.h>#include <net/if.h>#include <pthread.h>#include <netinet/in.h>#include <arpa/nameser.h>#include <resolv.h>#include "dns.h"#include "dns_util.h"#include "dns_private.h"#include "res_private.h"#define DNS_RESOLVER_DIR "/etc/resolver"#define DNS_PRIVATE_HANDLE_TYPE_SUPER 0#define DNS_PRIVATE_HANDLE_TYPE_PLAIN 1#define DNS_DEFAULT_RECEIVE_SIZE 8192#define DNS_MAX_RECEIVE_SIZE 65536#define SDNS_DEFAULT_STAT_LATENCY 10#define DNS_FLAGS_QR_MASK  0x8000#define DNS_FLAGS_QR_QUERY 0x0000#define DNS_FLAGS_OPCODE_MASK    0x7800#define DNS_FLAGS_RCODE_MASK 0x000f#define DNS_FLAGS_AA 0x0400#define DNS_FLAGS_TC 0x0200#define DNS_FLAGS_RD 0x0100#define DNS_FLAGS_RA 0x0080#define DNS_SOCK_UDP 0#define DNS_SOCK_TCP_UNCONNECTED 1#define DNS_SOCK_TCP_CONNECTED 2#define INET_NTOP_AF_INET_OFFSET 4#define INET_NTOP_AF_INET6_OFFSET 8#define MAXPACKET 1024extern void res_client_close(res_state res);extern int __res_nquery(res_state statp, const char *name, int class, int type, u_char *answer, int anslen);extern int dns_res_send(res_state statp, const u_char *buf, int buflen, u_char *ans, int *anssiz, struct sockaddr *from, int *fromlen);extern void _check_cache(sdns_handle_t *sdns);extern int _sdns_search(sdns_handle_t *sdns, const char *name, uint32_t class, uint32_t type, uint32_t fqdn, uint32_t recurse, char *buf, uint32_t len, struct sockaddr *from, uint32_t *fromlen, int *min);extern int _pdns_search(sdns_handle_t *sdns, pdns_handle_t *pdns, const char *name, uint32_t class, uint32_t type, char *buf, uint32_t len, struct sockaddr *from, uint32_t *fromlen);static pthread_mutex_t _dnsPrintLock = PTHREAD_MUTEX_INITIALIZER;static void_dns_print_lock(void){pthread_mutex_lock(&_dnsPrintLock);}static void_dns_print_unlock(void){pthread_mutex_unlock(&_dnsPrintLock);}static uint8_t_dns_parse_uint8(char **p){uint8_t v;v = (uint8_t)**p;*p += 1;return v;}static uint16_t_dns_parse_uint16(char **p){uint16_t *x, v;x = (uint16_t *)*p;v = ntohs(*x);*p += 2;return v;}static uint32_t_dns_parse_uint32(char **p){uint32_t *x, v;x = (uint32_t *)*p;v = ntohl(*x);*p += 4;return v;}static uint8_t_dns_cname_length(char *s){uint8_t l;if (s == NULL) return 1;l = strlen(s);while ((s[l - 1] == '.') && (l > 1)) l--;return l;}static void_dns_insert_cname(char *s, char *p){int i;uint8_t len, dlen;if (s == NULL){*p = 0;return;}if (!strcmp(s, ".")){p[0] = 1;p[1] = '.';p[2] = 0;return;}len = _dns_cname_length(s);p[0] = '.';memmove(p + 1, s, len);p[len + 1] = '.';dlen = 0;for (i = len + 1; i >= 0; i--){if (p[i] == '.'){p[i] = dlen;dlen = 0;}else dlen++;}}static char *_dns_parse_string(const char *p, char **x, int32_t *remaining){char *str;uint8_t len;if (*remaining < 1) return NULL;*remaining -= 1;len = (uint8_t)**x;*x += 1;if (*remaining < len) return NULL;*remaining -= len;str = malloc(len + 1);memmove(str, *x, len);str[len] = '\0';*x += len;return str;}static char *_dns_parse_domain_name(const char *p, char **x, int32_t *remaining){uint8_t *v8;uint16_t *v16, skip;uint16_t i, j, dlen, len;int more, compressed;char *name, *start, *y, *z;if (*remaining < 1) return NULL;z = *x + *remaining;start = *x;compressed = 0;more = 1;name = malloc(1);name[0] = '\0';len = 1;j = 0;skip = 0;while (more == 1){if ((*x + 1) > z){free(name);return NULL;}v8 = (uint8_t *)*x;dlen = *v8;if ((dlen & 0xc0) == 0xc0){if ((*x + 2) > z){free(name);return NULL;}v16 = (uint16_t *)*x;y = (char *)p + (ntohs(*v16) & 0x3fff);if ((*x == y) || (y > z)){free(name);return NULL;}*x = y;if (compressed == 0) skip += 2;compressed = 1;continue;}if ((*x + 1) > z){free(name);return NULL;}*x += 1;if (dlen > 0){len += dlen;name = realloc(name, len);}if ((*x + dlen) > z){free(name);return NULL;}for (i = 0; i < dlen; i++){name[j++] = **x;*x += 1;}name[j] = '\0';if (compressed == 0) skip += (dlen + 1);if (dlen == 0) more = 0;else{if ((*x + 1) > z){free(name);return NULL;}v8 = (uint8_t *)*x;if (*v8 != 0){len += 1;name = realloc(name, len);name[j++] = '.';name[j] = '\0';}}}if ((start + skip) > z){free(name);return NULL;}*x = start + skip;*remaining -= skip;return name;}dns_resource_record_t *_dns_parse_resource_record_internal(const char *p, char **x, int32_t *remaining){uint32_t size, bx, mi;uint16_t rdlen;uint8_t byte, i;dns_resource_record_t *r;char *eor;if (*remaining < 1) return NULL;r = (dns_resource_record_t *)calloc(1, sizeof(dns_resource_record_t));r->name = _dns_parse_domain_name(p, x, remaining);if (r->name == NULL){dns_free_resource_record(r);return NULL;}if (*remaining < 10){dns_free_resource_record(r);return NULL;}r->dnstype = _dns_parse_uint16(x);r->dnsclass = _dns_parse_uint16(x);r->ttl = _dns_parse_uint32(x);rdlen = _dns_parse_uint16(x);*remaining -= 10;if (*remaining < rdlen){dns_free_resource_record(r);return NULL;}eor = *x;r->data.A = NULL;switch (r->dnstype){case ns_t_a:if (*remaining < 4){dns_free_resource_record(r);return NULL;}*remaining -= 4;size = sizeof(dns_address_record_t);r->data.A = (dns_address_record_t *)calloc(1, size);r->data.A->addr.s_addr = htonl(_dns_parse_uint32(x));break;case ns_t_aaaa:if (*remaining < 16){dns_free_resource_record(r);return NULL;}*remaining -= 16;size = sizeof(dns_in6_address_record_t);r->data.AAAA = (dns_in6_address_record_t *)calloc(1, size);r->data.AAAA->addr.__u6_addr.__u6_addr32[0] = htonl(_dns_parse_uint32(x));r->data.AAAA->addr.__u6_addr.__u6_addr32[1] = htonl(_dns_parse_uint32(x));r->data.AAAA->addr.__u6_addr.__u6_addr32[2] = htonl(_dns_parse_uint32(x));r->data.AAAA->addr.__u6_addr.__u6_addr32[3] = htonl(_dns_parse_uint32(x));break;case ns_t_ns:case ns_t_md:case ns_t_mf:case ns_t_cname:case ns_t_mb:case ns_t_mg:case ns_t_mr:case ns_t_ptr:size = sizeof(dns_domain_name_record_t);r->data.CNAME = (dns_domain_name_record_t *)calloc(1,size);r->data.CNAME->name = _dns_parse_domain_name(p, x, remaining);if (r->data.CNAME->name == NULL){dns_free_resource_record(r);return NULL;}break;case ns_t_soa:size = sizeof(dns_SOA_record_t);r->data.SOA = (dns_SOA_record_t *)calloc(1, size);r->data.SOA->mname = _dns_parse_domain_name(p, x, remaining);if (r->data.SOA->mname == NULL){dns_free_resource_record(r);return NULL;}r->data.SOA->rname = _dns_parse_domain_name(p, x, remaining);if (r->data.SOA->rname == NULL){dns_free_resource_record(r);return NULL;}if (*remaining < 20) {dns_free_resource_record(r);return NULL;}*remaining -= 20;r->data.SOA->serial = _dns_parse_uint32(x);r->data.SOA->refresh = _dns_parse_uint32(x);r->data.SOA->retry = _dns_parse_uint32(x);r->data.SOA->expire = _dns_parse_uint32(x);r->data.SOA->minimum = _dns_parse_uint32(x);break;case ns_t_wks:if (*remaining < 5) {dns_free_resource_record(r);return NULL;}*remaining -= rdlen;size = sizeof(dns_WKS_record_t);r->data.WKS = (dns_WKS_record_t *)calloc(1, size);r->data.WKS->addr.s_addr = htonl(_dns_parse_uint32(x));r->data.WKS->protocol = _dns_parse_uint8(x);size = rdlen - 5;r->data.WKS->maplength = size * 8;r->data.WKS->map = NULL;if (size == 0) break;r->data.WKS->map = (uint8_t *)calloc(1, r->data.WKS->maplength);mi = 0;for (bx = 0; bx < size; bx++){byte = _dns_parse_uint8(x);for (i = 128; i >= 1; i = i/2){if (byte & i) r->data.WKS->map[mi] = 0xff;else r->data.WKS->map[mi] = 0;mi++;}}break;case ns_t_hinfo:size = sizeof(dns_HINFO_record_t);r->data.HINFO = (dns_HINFO_record_t *)calloc(1, size);r->data.HINFO->cpu = _dns_parse_string(p, x, remaining);if (r->data.HINFO->cpu == NULL){dns_free_resource_record(r);return NULL;}r->data.HINFO->os = _dns_parse_string(p, x, remaining);if (r->data.HINFO->os == NULL){dns_free_resource_record(r);return NULL;}break;case ns_t_minfo:size = sizeof(dns_MINFO_record_t);r->data.MINFO = (dns_MINFO_record_t *)calloc(1, size);r->data.MINFO->rmailbx = _dns_parse_domain_name(p, x, remaining);if (r->data.MINFO->rmailbx == NULL){dns_free_resource_record(r);return NULL;}r->data.MINFO->emailbx = _dns_parse_domain_name(p, x, remaining);if (r->data.MINFO->emailbx == NULL){dns_free_resource_record(r);return NULL;}break;case ns_t_mx:if (*remaining < 2) {dns_free_resource_record(r);return NULL;}*remaining -= 2;size = sizeof(dns_MX_record_t);r->data.MX = (dns_MX_record_t *)calloc(1, size);r->data.MX->preference = _dns_parse_uint16(x);r->data.MX->name = _dns_parse_domain_name(p, x, remaining);if (r->data.MX->name == NULL){dns_free_resource_record(r);return NULL;}break;case ns_t_txt:size = sizeof(dns_TXT_record_t);r->data.TXT = (dns_TXT_record_t *)malloc(size);r->data.TXT->string_count = 0;r->data.TXT->strings = NULL;while (*x < (eor + rdlen)){if (r->data.TXT->string_count == 0){r->data.TXT->strings = (char **)calloc(1, sizeof(char *));}else{r->data.TXT->strings = (char **)realloc(r->data.TXT->strings, (r->data.TXT->string_count + 1) * sizeof(char *));}r->data.TXT->strings[r->data.TXT->string_count] = _dns_parse_string(p, x, remaining);if (r->data.TXT->strings[r->data.TXT->string_count] == NULL){dns_free_resource_record(r);return NULL;}r->data.TXT->string_count++;}break;case ns_t_rp:size = sizeof(dns_RP_record_t);r->data.RP = (dns_RP_record_t *)calloc(1, size);r->data.RP->mailbox = _dns_parse_domain_name(p, x, remaining);if (r->data.RP->mailbox == NULL){dns_free_resource_record(r);return NULL;}r->data.RP->txtdname = _dns_parse_domain_name(p, x, remaining);if (r->data.RP->txtdname == NULL){dns_free_resource_record(r);return NULL;}break;case ns_t_afsdb:if (*remaining < 4) {dns_free_resource_record(r);return NULL;}*remaining -= 4;size = sizeof(dns_AFSDB_record_t);r->data.AFSDB = (dns_AFSDB_record_t *)calloc(1, size);r->data.AFSDB->subtype = _dns_parse_uint32(x);r->data.AFSDB->hostname = _dns_parse_domain_name(p, x, remaining);if (r->data.AFSDB->hostname == NULL){dns_free_resource_record(r);return NULL;}break;case ns_t_x25:size = sizeof(dns_X25_record_t);r->data.X25 = (dns_X25_record_t *)calloc(1, size);r->data.X25->psdn_address = _dns_parse_string(p, x, remaining);if (r->data.X25->psdn_address == NULL){dns_free_resource_record(r);return NULL;}break;case ns_t_isdn:size = sizeof(dns_ISDN_record_t);r->data.ISDN = (dns_ISDN_record_t *)calloc(1, size);r->data.ISDN->isdn_address = _dns_parse_string(p, x, remaining);if (r->data.ISDN->isdn_address == NULL){dns_free_resource_record(r);return NULL;}if (*x < (eor + rdlen)){r->data.ISDN->subaddress = _dns_parse_string(p, x, remaining);if (r->data.ISDN->subaddress == NULL){dns_free_resource_record(r);return NULL;}}else{r->data.ISDN->subaddress = NULL;}break;case ns_t_rt:if (*remaining < 2) {dns_free_resource_record(r);return NULL;}*remaining -= 2;size = sizeof(dns_RT_record_t);r->data.RT = (dns_RT_record_t *)calloc(1, size);r->data.RT->preference = _dns_parse_uint16(x);r->data.RT->intermediate = _dns_parse_domain_name(p, x, remaining);if (r->data.RT->intermediate == NULL){dns_free_resource_record(r);return NULL;}break;case ns_t_loc:if (*remaining < 16) {dns_free_resource_record(r);return NULL;}*remaining -= 16;size = sizeof(dns_LOC_record_t);r->data.LOC = (dns_LOC_record_t *)calloc(1, size);r->data.LOC->version = _dns_parse_uint8(x);r->data.LOC->size = _dns_parse_uint8(x);r->data.LOC->horizontal_precision = _dns_parse_uint8(x);r->data.LOC->vertical_precision = _dns_parse_uint8(x);r->data.LOC->latitude = _dns_parse_uint32(x);r->data.LOC->longitude = _dns_parse_uint32(x);r->data.LOC->altitude = _dns_parse_uint32(x);break;case ns_t_srv:if (*remaining < 6) {dns_free_resource_record(r);return NULL;}*remaining -= 6;size = sizeof(dns_SRV_record_t);r->data.SRV = (dns_SRV_record_t *)calloc(1, size);r->data.SRV->priority = _dns_parse_uint16(x);r->data.SRV->weight = _dns_parse_uint16(x);r->data.SRV->port = _dns_parse_uint16(x);r->data.SRV->target = _dns_parse_domain_name(p, x, remaining);if (r->data.SRV->target == NULL){dns_free_resource_record(r);return NULL;}break;case ns_t_null:default:*remaining -= rdlen;size = sizeof(dns_raw_resource_record_t);r->data.DNSNULL = (dns_raw_resource_record_t *)calloc(1, size);r->data.DNSNULL->length = rdlen;r->data.DNSNULL->data = calloc(1, rdlen);memmove(r->data.DNSNULL->data, *x, rdlen);*x += rdlen;break;}*x = eor + rdlen;return r;}dns_resource_record_t *dns_parse_resource_record(const char *buf, uint32_t len){char *x;int32_t remaining;remaining = len;x = (char *)buf;return _dns_parse_resource_record_internal(buf, &x, &remaining);}dns_question_t *_dns_parse_question_internal(const char *p, char **x, int32_t *remaining){dns_question_t *q;if (x == NULL) return NULL;if (*x == NULL) return NULL;if (*remaining < 1) return NULL;q = (dns_question_t *)calloc(1, sizeof(dns_question_t));q->name = _dns_parse_domain_name(p, x, remaining);if (q->name == NULL){free(q);return NULL;}if (*remaining < 4){free(q->name);free(q);return NULL;}*remaining = *remaining - 4;q->dnstype = _dns_parse_uint16(x);q->dnsclass = _dns_parse_uint16(x);return q;}dns_question_t *dns_parse_question(const char *buf, uint32_t len){char *x;int32_t remaining;remaining = len;x = (char *)buf;return _dns_parse_question_internal(buf, &x, &remaining);}dns_reply_t *dns_parse_packet(const char *p, uint32_t len){dns_reply_t *r;dns_header_t *h;char *x;uint32_t i, size;    int32_t remaining;if (p == NULL) return NULL;if (len < NS_HFIXEDSZ) return NULL;x = (char *)p;r = (dns_reply_t *)calloc(1, sizeof(dns_reply_t));r->header = (dns_header_t *)calloc(1, sizeof(dns_header_t));h = r->header;h->xid = _dns_parse_uint16(&x);h->flags = _dns_parse_uint16(&x);h->qdcount = _dns_parse_uint16(&x);h->ancount = _dns_parse_uint16(&x);h->nscount = _dns_parse_uint16(&x);h->arcount = _dns_parse_uint16(&x);remaining = len - NS_HFIXEDSZ;size = sizeof(dns_question_t *);r->question = (dns_question_t **)calloc(h->qdcount, size);for (i = 0; i < h->qdcount; i++){r->question[i] = _dns_parse_question_internal(p, &x, &remaining);if (r->question[i] ==NULL){h->qdcount = 0;if (i > 0) h->qdcount = i - 1;h->ancount = 0;h->nscount = 0;h->arcount = 0;dns_free_reply(r);return NULL;}}size = sizeof(dns_resource_record_t *);r->answer = (dns_resource_record_t **)calloc(h->ancount, size);for (i = 0; i < h->ancount; i++){r->answer[i] = _dns_parse_resource_record_internal(p, &x, &remaining);if (r->answer[i] == NULL){h->ancount = 0;if (i > 0) h->ancount = i - 1;h->nscount = 0;h->arcount = 0;dns_free_reply(r);return NULL;}}r->authority = (dns_resource_record_t **)calloc(h->nscount, size);for (i = 0; i < h->nscount; i++){r->authority[i] = _dns_parse_resource_record_internal(p, &x, &remaining);if (r->authority[i] == NULL){h->nscount = 0;if (i > 0) h->nscount = i - 1;h->arcount = 0;dns_free_reply(r);return NULL;}}r->additional = (dns_resource_record_t **)calloc(h->arcount, size);for (i = 0; i < h->arcount; i++){r->additional[i] = _dns_parse_resource_record_internal(p, &x, &remaining);if (r->additional[i] == NULL){h->arcount = 0;if (i > 0) h->arcount = i - 1;dns_free_reply(r);return NULL;}}return r;}voiddns_free_resource_record(dns_resource_record_t *r){int i;free(r->name);switch (r->dnstype){case ns_t_a:if (r->data.A != NULL) free(r->data.A);break;case ns_t_aaaa:if (r->data.AAAA != NULL) free(r->data.AAAA);break;case ns_t_ns:case ns_t_md:case ns_t_mf:case ns_t_cname:case ns_t_mb:case ns_t_mg:case ns_t_mr:case ns_t_ptr:if (r->data.CNAME != NULL){if (r->data.CNAME->name != NULL) free(r->data.CNAME->name);free(r->data.CNAME);}break;case ns_t_soa:if (r->data.SOA != NULL){if (r->data.SOA->mname != NULL) free(r->data.SOA->mname);if (r->data.SOA->rname != NULL) free(r->data.SOA->rname);free(r->data.SOA);}break;case ns_t_wks:if (r->data.WKS != NULL){if (r->data.WKS->map != NULL) free(r->data.WKS->map);free(r->data.WKS);}break;case ns_t_hinfo:if (r->data.HINFO != NULL){if (r->data.HINFO->cpu != NULL) free(r->data.HINFO->cpu);if (r->data.HINFO->os != NULL) free(r->data.HINFO->os);free(r->data.HINFO);}break;case ns_t_minfo:if (r->data.MINFO != NULL){if (r->data.MINFO->rmailbx != NULL) free(r->data.MINFO->rmailbx);if (r->data.MINFO->emailbx != NULL) free(r->data.MINFO->emailbx);free(r->data.MINFO);}break;case ns_t_mx:if (r->data.MX != NULL){if (r->data.MX->name != NULL) free(r->data.MX->name);free(r->data.MX);}break;case ns_t_txt:if (r->data.TXT != NULL){for (i = 0; i < r->data.TXT->string_count; i++) free(r->data.TXT->strings[i]);if (r->data.TXT->strings != NULL) free(r->data.TXT->strings);free(r->data.TXT);}break;case ns_t_rp:if (r->data.RP != NULL){if (r->data.RP->mailbox != NULL) free(r->data.RP->mailbox);if (r->data.RP->txtdname != NULL) free(r->data.RP->txtdname);free(r->data.RP);}break;case ns_t_afsdb:if (r->data.AFSDB != NULL){if (r->data.AFSDB->hostname != NULL) free(r->data.AFSDB->hostname);free(r->data.AFSDB);}break;case ns_t_x25:if (r->data.X25 != NULL){if (r->data.X25->psdn_address != NULL) free(r->data.X25->psdn_address);free(r->data.X25);}break;case ns_t_isdn:if (r->data.ISDN != NULL){if (r->data.ISDN->isdn_address != NULL) free(r->data.ISDN->isdn_address);if (r->data.ISDN->subaddress != NULL) free(r->data.ISDN->subaddress);free(r->data.ISDN);}break;case ns_t_rt:if (r->data.RT != NULL){if (r->data.RT->intermediate != NULL) free(r->data.RT->intermediate);free(r->data.RT);}break;case ns_t_loc:if (r->data.LOC != NULL) free(r->data.LOC);break;case ns_t_srv:if (r->data.SRV != NULL){if (r->data.SRV->target != NULL) free(r->data.SRV->target);free(r->data.SRV);}break;case ns_t_invalid:break;case ns_t_null:default:if (r->data.DNSNULL != NULL){if (r->data.DNSNULL->data != NULL) free(r->data.DNSNULL->data);free(r->data.DNSNULL);}break;}free(r);}voiddns_free_reply(dns_reply_t *r){uint32_t i;if (r == NULL) return;if (r->header != NULL){for (i = 0; i < r->header->qdcount; i++){free(r->question[i]->name);free(r->question[i]);}for (i = 0; i < r->header->ancount; i++) dns_free_resource_record(r->answer[i]);for (i = 0; i < r->header->nscount; i++) dns_free_resource_record(r->authority[i]);for (i = 0; i < r->header->arcount; i++) dns_free_resource_record(r->additional[i]);free(r->header);}if (r->question != NULL) free(r->question);if (r->answer != NULL) free(r->answer);if (r->authority != NULL) free(r->authority);if (r->additional != NULL) free(r->additional);if (r->server != NULL) free(r->server);free(r);}static void_dns_append_question(dns_question_t *q, char **s, uint16_t *l){uint16_t len, *p;char *x;if (q == NULL) return;len = *l + _dns_cname_length(q->name) + 2 + 4;*s = realloc(*s, len);_dns_insert_cname(q->name, (char *)*s + *l);*l = len;x = *s + (len - 4);p = (uint16_t *)x;*p = htons(q->dnstype);x += 2;p = (uint16_t *)x;*p = htons(q->dnsclass);}static void_dns_append_resource_record(dns_resource_record_t *r, char **s, uint16_t *l){uint16_t clen, len, *p, extra, rdlen;uint32_t *p2;char *x;if (r == NULL) return;extra = 10;switch (r->dnstype){case ns_t_a:extra += 4;break;case ns_t_ptr:extra += 2;clen = _dns_cname_length(r->data.PTR->name);extra += clen;break;default: break;}len = *l + _dns_cname_length(r->name) + 2 + extra;*s = realloc(*s, len);_dns_insert_cname(r->name, (char *)*s + *l);*l = len;x = *s + (len - extra);p = (uint16_t *)x;*p = htons(r->dnstype);x += 2;p = (uint16_t *)x;*p = htons(r->dnsclass);x += 2;p2 = (uint32_t *)x;*p2 = htonl(r->ttl);x += 4;switch (r->dnstype){case ns_t_a:rdlen = 4;p = (uint16_t *)x;*p = htons(rdlen);x += 2;p2 = (uint32_t *)x;*p2 = htons(r->data.A->addr.s_addr);x += 4;return;case ns_t_ptr:clen = _dns_cname_length(r->data.PTR->name) + 2;p = (uint16_t *)x;*p = htons(clen);x += 2;_dns_insert_cname(r->data.PTR->name, x);x += clen;return;default: return;}}char *dns_build_reply(dns_reply_t *dnsr, uint16_t *rl){uint16_t i, len;dns_header_t *h;char *s, *x;if (dnsr == NULL) return NULL;len = NS_HFIXEDSZ;s = malloc(len);x = s + len;memset(s, 0, len);*rl = len;h = (dns_header_t *)s;h->xid = htons(dnsr->header->xid);h->flags = htons(dnsr->header->flags);h->qdcount = htons(dnsr->header->qdcount);h->ancount = htons(dnsr->header->ancount);h->nscount = htons(dnsr->header->nscount);h->arcount = htons(dnsr->header->arcount);for (i = 0; i < dnsr->header->qdcount; i++){_dns_append_question(dnsr->question[i], &s, rl);}for (i = 0; i < dnsr->header->ancount; i++){_dns_append_resource_record(dnsr->answer[i], &s, rl);}for (i = 0; i < dnsr->header->nscount; i++){_dns_append_resource_record(dnsr->authority[i], &s, rl);}for (i = 0; i < dnsr->header->arcount; i++){_dns_append_resource_record(dnsr->additional[i], &s, rl);}return s;}voiddns_free_question(dns_question_t *q){if (q == NULL) return;if (q->name != NULL) free(q->name);free(q);}voiddns_set_buffer_size(dns_handle_t d, uint32_t len){dns_private_handle_t *dns;if (d == NULL) return;dns = (dns_private_handle_t *)d;if (dns->recvsize == len) return;if (dns->recvbuf != NULL){free(dns->recvbuf);dns->recvbuf = NULL;}dns->recvsize = len;if (dns->recvsize > DNS_MAX_RECEIVE_SIZE) dns->recvsize = DNS_MAX_RECEIVE_SIZE;if (dns->recvsize > 0) dns->recvbuf = malloc(dns->recvsize);}uint32_tdns_get_buffer_size(dns_handle_t d){dns_private_handle_t *dns;if (d == NULL) return 0;dns = (dns_private_handle_t *)d;return dns->recvsize;}dns_reply_t *dns_lookup_soa_min(dns_handle_t d, const char *name, uint32_t class, uint32_t type, int *min){dns_private_handle_t *dns;dns_reply_t *r;int len;struct sockaddr_storage *from;uint32_t fromlen;if (d == NULL) return NULL;if (name == NULL) return NULL;dns = (dns_private_handle_t *)d;if (min != NULL) *min = -1;if (dns->recvbuf == NULL){if (dns->recvsize == 0) dns->recvsize = DNS_DEFAULT_RECEIVE_SIZE;dns->recvbuf = malloc(dns->recvsize);if (dns->recvbuf == NULL) return NULL;}fromlen = sizeof(struct sockaddr_storage);from = (struct sockaddr_storage *)calloc(1, sizeof(struct sockaddr_storage));len = -1;if (dns->handle_type == DNS_PRIVATE_HANDLE_TYPE_SUPER){_check_cache(dns->sdns);len = _sdns_search(dns->sdns, name, class, type, 0, 1,  dns->recvbuf, dns->recvsize, (struct sockaddr *)from, &fromlen, min);}else{/* NB.  Minumium SOA TTL values are NOT provided when the caller passes a DNS_PRIVATE_HANDLE_TYPE_PLAIN handle */len = _pdns_search(dns->sdns, dns->pdns, name, class, type,  dns->recvbuf, dns->recvsize, (struct sockaddr *)from, &fromlen);}if (len <= 0){free(from);return NULL;}r = dns_parse_packet(dns->recvbuf, len);if (r == NULL) free(from);else r->server = (struct sockaddr *)from;return r;}dns_reply_t *dns_lookup(dns_handle_t d, const char *name, uint32_t class, uint32_t type){int unused = 0;return dns_lookup_soa_min(d, name, class, type, &unused);}/* * DNS printing utilities */static char *coord_ntoa(int32_t coord, uint32_t islat){int32_t deg, min, sec, secfrac;static char buf[64];char dir;coord = coord - 0x80000000;dir = 'N';if ((islat == 1) && (coord < 0)){dir = 'S';coord = -coord;}if (islat == 0){dir = 'E';if (coord < 0){dir = 'W';coord = -coord;}}secfrac = coord % 1000;coord = coord / 1000;sec = coord % 60;coord = coord / 60;min = coord % 60;coord = coord / 60;deg = coord;sprintf(buf, "%d %.2d %.2d.%.3d %c", deg, min, sec, secfrac, dir);return buf;}static char *alt_ntoa(int32_t alt){int32_t ref, m, frac, sign;static char buf[128];ref = 100000 * 100;sign = 1;if (alt < ref){alt = ref - alt;sign = -1;}else{alt = alt - ref;}frac = alt % 100;m = (alt / 100) * sign;sprintf(buf, "%d.%.2d", m, frac);return buf;}static unsigned intpoweroften[10] ={1,10,100,1000,10000,100000,1000000,10000000,100000000,1000000000};static char *precsize_ntoa(uint8_t prec){static char buf[19];unsigned long val;int mantissa, exponent;mantissa = (int)((prec >> 4) & 0x0f) % 10;exponent = (int)((prec >> 0) & 0x0f) % 10;val = mantissa * poweroften[exponent];sprintf(buf, "%ld.%.2ld", val/100, val%100);return buf;}const char *dns_type_string(uint16_t t){switch (t){case ns_t_a:     return "A    ";case ns_t_ns:    return "NS   ";case ns_t_md:    return "MD   ";case ns_t_mf:    return "MF   ";case ns_t_cname: return "CNAME";case ns_t_soa:   return "SOA  ";case ns_t_mb:    return "MB  ";case ns_t_mg:    return "MG   ";case ns_t_mr:    return "MR   ";case ns_t_null:  return "NULL ";case ns_t_wks:   return "WKS  ";case ns_t_ptr:   return "PTR  ";case ns_t_hinfo: return "HINFO";case ns_t_minfo: return "MINFO";case ns_t_mx:    return "MX   ";case ns_t_txt:   return "TXT  ";case ns_t_rp:    return "PR   ";case ns_t_afsdb: return "AFSDB";case ns_t_x25:   return "X25  ";case ns_t_isdn:  return "ISDN ";case ns_t_rt:    return "RT   ";case ns_t_nsap:  return "NSAP ";case ns_t_nsap_ptr: return "NSPTR";case ns_t_sig:   return "SIG  ";case ns_t_key:   return "KEY  ";case ns_t_px:    return "PX   ";case ns_t_gpos:  return "GPOS ";case ns_t_aaaa:  return "AAAA ";case ns_t_loc:   return "LOC  ";case ns_t_nxt:   return "NXT  ";case ns_t_eid:   return "EID  ";case ns_t_nimloc: return "NIMLC";case ns_t_srv:   return "SRV  ";case ns_t_atma:  return "ATMA ";case ns_t_naptr: return "NAPTR";case ns_t_kx:    return "KX   ";case ns_t_cert:  return "CERT ";case ns_t_a6:    return "A6   ";case ns_t_dname: return "DNAME";case ns_t_sink:  return "SINK ";case ns_t_opt:   return "OPT  ";case ns_t_tkey:  return "TKEY ";case ns_t_tsig:  return "TSIG ";case ns_t_ixfr:  return "IXFR ";case ns_t_axfr:  return "AXFR ";case ns_t_mailb: return "MAILB";case ns_t_maila: return "MAILA";case ns_t_any:   return "ANY  ";case ns_t_zxfr:  return "ZXFR ";default:         return "?????";}return "?????";}int32_tdns_type_number(const char *t, uint16_t *n){if (t == NULL) return -1;if (!strcasecmp(t, "A"))       { *n = ns_t_a;        return 0; }if (!strcasecmp(t, "NS"))      { *n = ns_t_ns;       return 0; }if (!strcasecmp(t, "MD"))      { *n = ns_t_md;       return 0; }if (!strcasecmp(t, "MF"))      { *n = ns_t_mf;       return 0; }if (!strcasecmp(t, "CNAME"))   { *n = ns_t_cname;    return 0; }if (!strcasecmp(t, "SOA"))     { *n = ns_t_soa;      return 0; }if (!strcasecmp(t, "MB"))      { *n = ns_t_mb;       return 0; }if (!strcasecmp(t, "MG"))      { *n = ns_t_mg;       return 0; }if (!strcasecmp(t, "MR"))      { *n = ns_t_mr;       return 0; }if (!strcasecmp(t, "NULL"))    { *n = ns_t_null;     return 0; }if (!strcasecmp(t, "WKS"))     { *n = ns_t_wks;      return 0; }if (!strcasecmp(t, "PTR"))     { *n = ns_t_ptr;      return 0; }if (!strcasecmp(t, "HINFO"))   { *n = ns_t_hinfo;    return 0; }if (!strcasecmp(t, "MINFO"))   { *n = ns_t_minfo;    return 0; }if (!strcasecmp(t, "MX"))      { *n = ns_t_mx;       return 0; }if (!strcasecmp(t, "TXT"))     { *n = ns_t_txt;      return 0; }if (!strcasecmp(t, "RP"))      { *n = ns_t_rp;       return 0; }if (!strcasecmp(t, "AFSDB"))   { *n = ns_t_afsdb;    return 0; }if (!strcasecmp(t, "X25"))     { *n = ns_t_x25;      return 0; }if (!strcasecmp(t, "ISDN"))    { *n = ns_t_isdn;     return 0; }if (!strcasecmp(t, "RT"))      { *n = ns_t_rt;       return 0; }if (!strcasecmp(t, "NSAP"))    { *n = ns_t_nsap;     return 0; }if (!strcasecmp(t, "NSPTR"))   { *n = ns_t_nsap_ptr; return 0; }if (!strcasecmp(t, "NSAP_PTR")){ *n = ns_t_nsap_ptr; return 0; }if (!strcasecmp(t, "SIG"))     { *n = ns_t_sig;      return 0; }if (!strcasecmp(t, "KEY"))     { *n = ns_t_key;      return 0; }if (!strcasecmp(t, "PX"))      { *n = ns_t_px;       return 0; }if (!strcasecmp(t, "GPOS"))    { *n = ns_t_gpos;     return 0; }if (!strcasecmp(t, "AAAA"))    { *n = ns_t_aaaa;     return 0; }if (!strcasecmp(t, "LOC"))     { *n = ns_t_loc;      return 0; }if (!strcasecmp(t, "NXT"))     { *n = ns_t_nxt;      return 0; }if (!strcasecmp(t, "EID"))     { *n = ns_t_eid;      return 0; }if (!strcasecmp(t, "NIMLOC"))  { *n = ns_t_nimloc;   return 0; }if (!strcasecmp(t, "SRV"))     { *n = ns_t_srv;      return 0; }if (!strcasecmp(t, "ATMA"))    { *n = ns_t_atma;     return 0; }if (!strcasecmp(t, "NAPTR"))   { *n = ns_t_naptr;    return 0; }if (!strcasecmp(t, "KX"))      { *n = ns_t_kx;       return 0; }if (!strcasecmp(t, "CERT"))    { *n = ns_t_cert;     return 0; }if (!strcasecmp(t, "A6"))      { *n = ns_t_a6;       return 0; }if (!strcasecmp(t, "DNAME"))   { *n = ns_t_dname;    return 0; }if (!strcasecmp(t, "SINK"))    { *n = ns_t_sink;     return 0; }if (!strcasecmp(t, "OPT"))     { *n = ns_t_opt;      return 0; }if (!strcasecmp(t, "TKEY"))    { *n = ns_t_tkey;     return 0; }if (!strcasecmp(t, "TSIG"))    { *n = ns_t_tsig;     return 0; }if (!strcasecmp(t, "IXFR"))    { *n = ns_t_ixfr;     return 0; }if (!strcasecmp(t, "AXFR"))    { *n = ns_t_axfr;     return 0; }if (!strcasecmp(t, "MAILB"))   { *n = ns_t_mailb;    return 0; }if (!strcasecmp(t, "MAILA"))   { *n = ns_t_maila;    return 0; }if (!strcasecmp(t, "ANY"))     { *n = ns_t_any;      return 0; }if (!strcasecmp(t, "ZXFR"))    { *n = ns_t_zxfr;     return 0; }return -1;}const char *dns_class_string(uint16_t c){switch (c){case ns_c_in: return "IN";case ns_c_2: return "CS";case ns_c_chaos: return "CH";case ns_c_hs: return "HS";case ns_c_none: return "NONE";case ns_c_any: return "ANY";default: return "??";}return "??";}int32_tdns_class_number(const char *c, uint16_t *n){if (c == NULL) return -1;if (!strcasecmp(c, "IN"))   { *n = ns_c_in;    return 0; }if (!strcasecmp(c, "CS"))   { *n = ns_c_2;     return 0; }if (!strcasecmp(c, "CH"))   { *n = ns_c_chaos; return 0; }if (!strcasecmp(c, "HS"))   { *n = ns_c_hs;    return 0; }if (!strcasecmp(c, "NONE")) { *n = ns_c_none;  return 0; }if (!strcasecmp(c, "ANY"))  { *n = ns_c_any;   return 0; }return -1;}static void_dns_print_question_lock(const dns_question_t *q, FILE *f, int lockit){if (lockit != 0) _dns_print_lock();fprintf(f, "%s %s %s\n", q->name, dns_class_string(q->dnsclass), dns_type_string(q->dnstype));if (lockit != 0) _dns_print_unlock();}voiddns_print_question(const dns_question_t *q, FILE *f){_dns_print_question_lock(q, f, 1);}static void_dns_print_resource_record_lock(const dns_resource_record_t *r, FILE *f, int lockit){struct protoent *p;struct servent *s;uint32_t i, len;uint8_t x;struct sockaddr_in6 s6;char pbuf[64];if (lockit != 0) _dns_print_lock();fprintf(f, "%s %s %s ", r->name, dns_class_string(r->dnsclass), dns_type_string(r->dnstype));fprintf(f, "%u", r->ttl);switch (r->dnstype){case ns_t_a:fprintf(f, " %s", inet_ntoa(r->data.A->addr));break;case ns_t_aaaa:memset(&s6, 0, sizeof(struct sockaddr_in6));s6.sin6_len = sizeof(struct sockaddr_in6);s6.sin6_family = AF_INET6;s6.sin6_addr = r->data.AAAA->addr;fprintf(f, " %s", inet_ntop(AF_INET6, (char *)(&s6) + INET_NTOP_AF_INET6_OFFSET, pbuf, 64));break;case ns_t_md:case ns_t_mf:case ns_t_cname:case ns_t_mb:case ns_t_mg:case ns_t_mr:case ns_t_ptr:case ns_t_ns:fprintf(f, " %s", r->data.CNAME->name);break;case ns_t_soa:fprintf(f, " %s %s %u %u %u %u %u",r->data.SOA->mname, r->data.SOA->rname,r->data.SOA->serial, r->data.SOA->refresh, r->data.SOA->retry,r->data.SOA->expire, r->data.SOA->minimum);break;case ns_t_wks:fprintf(f, " %s", inet_ntoa(r->data.WKS->addr));p = getprotobynumber(r->data.WKS->protocol);if (p != NULL){fprintf(f, " %s", p->p_name);for (i = 0; i < r->data.WKS->maplength; i++){if (r->data.WKS->map[i]){s = getservbyport(i, p->p_name);if (s == NULL) fprintf(f, " %u", i);else fprintf(f, " %s", s->s_name);}}}else fprintf(f, " UNKNOWN PROTOCOL %u", r->data.WKS->protocol);break;case ns_t_hinfo:fprintf(f, " %s %s", r->data.HINFO->cpu, r->data.HINFO->os);break;case ns_t_minfo:fprintf(f, " %s %s", r->data.MINFO->rmailbx, r->data.MINFO->emailbx);break;case ns_t_mx:fprintf(f, " %u %s", r->data.MX->preference, r->data.MX->name);break;case ns_t_txt:for (i = 0; i < r->data.TXT->string_count; i++){fprintf(f, " \"%s\"", r->data.TXT->strings[i]);}break;case ns_t_rp:fprintf(f, " %s %s", r->data.RP->mailbox, r->data.RP->txtdname);break;case ns_t_afsdb:fprintf(f, " %u %s", r->data.AFSDB->subtype,r->data.AFSDB->hostname);break;case ns_t_x25:fprintf(f, " %s", r->data.X25->psdn_address);break;case ns_t_isdn:fprintf(f, " %s", r->data.ISDN->isdn_address);if (r->data.ISDN->subaddress != NULL)fprintf(f, " %s", r->data.ISDN->subaddress);break;case ns_t_rt:fprintf(f, " %hu %s", r->data.RT->preference,r->data.RT->intermediate);break;case ns_t_loc:fprintf(f, " %s", coord_ntoa(r->data.LOC->latitude, 1));fprintf(f, " %s", coord_ntoa(r->data.LOC->longitude, 0));fprintf(f, " %sm", alt_ntoa(r->data.LOC->altitude));fprintf(f, " %sm", precsize_ntoa(r->data.LOC->size));fprintf(f, " %sm", precsize_ntoa(r->data.LOC->horizontal_precision));fprintf(f, " %sm", precsize_ntoa(r->data.LOC->vertical_precision));break;case ns_t_srv:fprintf(f, " %hu %hu %hu %s",r->data.SRV->priority, r->data.SRV->weight, r->data.SRV->port, r->data.SRV->target);break;case ns_t_null:default:len = r->data.DNSNULL->length;fprintf(f, " %u ", len);for (i = 0; i < len; i++){x = r->data.DNSNULL->data[i];fprintf(f, "%x", x);}fprintf(f, " (");len = r->data.DNSNULL->length;for (i = 0; i < len; i++){x = r->data.DNSNULL->data[i];if (isascii(x)) fprintf(f, "%c", x);else fprintf(f, " ");}fprintf(f, ")\n");}fprintf(f, "\n");if (lockit != 0) _dns_print_unlock();}voiddns_print_resource_record(const dns_resource_record_t *r, FILE *f){_dns_print_resource_record_lock(r, f, 1);}voiddns_print_reply(const dns_reply_t *r, FILE *f, uint16_t mask){uint16_t i;dns_header_t *h;char scratch[1024];uint32_t offset, iface;_dns_print_lock();if (r == NULL){fprintf(f, "-nil-\n");_dns_print_unlock();return;}if (r->status != DNS_STATUS_OK){if (r->status == DNS_STATUS_TIMEOUT)fprintf(f, "Timeout\n");else if (r->status == DNS_STATUS_SEND_FAILED)fprintf(f, "Send failed\n");else if (r->status == DNS_STATUS_RECEIVE_FAILED)fprintf(f, "Receive failed\n");else fprintf(f, "status %u\n", r->status);_dns_print_unlock();return;}h = r->header;if (mask & DNS_PRINT_XID){fprintf(f, "Xid: %u\n", h->xid);}if (mask & DNS_PRINT_QR){if ((h->flags & DNS_FLAGS_QR_MASK) == DNS_FLAGS_QR_QUERY)fprintf(f, "QR: Query\n");elsefprintf(f, "QR: Reply\n");}if (mask & DNS_PRINT_SERVER){if (r->server == NULL){fprintf(f, "Server: -nil-\n");}else{offset = INET_NTOP_AF_INET_OFFSET;if (r->server->sa_family == AF_INET6) offset = INET_NTOP_AF_INET6_OFFSET;fprintf(f, "Server: %s", inet_ntop(r->server->sa_family, (char *)(r->server) + offset, scratch, 1024));if (r->server->sa_family == AF_INET){memcpy(&iface, (((struct sockaddr_in *)(r->server))->sin_zero), 4);if (iface > 0) fprintf(f, "%%%s", if_indextoname(iface, scratch));}else if (r->server->sa_family == AF_INET6){iface = ((struct sockaddr_in6 *)(r->server))->sin6_scope_id;if (iface > 0) fprintf(f, "%%%s", if_indextoname(iface, scratch));}fprintf(f, "\n");}}if (mask & DNS_PRINT_OPCODE){fprintf(f, "Opcode: ");switch (h->flags & DNS_FLAGS_OPCODE_MASK){case ns_o_query:  fprintf(f, "Standard\n"); break;case ns_o_iquery: fprintf(f, "Inverse\n"); break;case ns_o_status: fprintf(f, "Status\n"); break;case ns_o_notify: fprintf(f, "Notify\n"); break;case ns_o_update: fprintf(f, "Update\n"); break;default:fprintf(f, "Reserved (%hu)\n",(uint16_t)((h->flags & DNS_FLAGS_OPCODE_MASK) >> 11));}}if (mask & DNS_PRINT_AA){if (h->flags & DNS_FLAGS_AA) fprintf(f, "AA: Authoritative\n");else fprintf(f, "AA: Non-Authoritative\n");}if (mask & DNS_PRINT_TC){if (h->flags & DNS_FLAGS_TC) fprintf(f, "TC: Truncated\n");else fprintf(f, "TC: Non-Truncated\n");}if (mask & DNS_PRINT_RD){if (h->flags & DNS_FLAGS_RD) fprintf(f, "RD: Recursion desired\n");else fprintf(f, "RD: No recursion desired\n");}if (mask & DNS_PRINT_RA){if (h->flags & DNS_FLAGS_RA) fprintf(f, "RA: Recursion available\n");else fprintf(f, "RA: No recursion available \n");}if (mask & DNS_PRINT_RCODE){fprintf(f, "Rcode: ");switch (h->flags & DNS_FLAGS_RCODE_MASK){case ns_r_noerror:fprintf(f, "No error\n");break;case ns_r_formerr:fprintf(f, "Format error \n");break;case ns_r_servfail:fprintf(f, "Server failure\n");break;case ns_r_nxdomain:fprintf(f, "Name error \n");break;case ns_r_notimpl:fprintf(f, "Not implemented\n");break;case ns_r_refused:fprintf(f, "Refused\n");break;case ns_r_yxdomain:fprintf(f, "Name exists\n");break;case ns_r_yxrrset:fprintf(f, "RR Set exists\n");break;case ns_r_nxrrset:fprintf(f, "RR Set does not exist\n");break;case ns_r_notauth:fprintf(f, "Not authoritative\n");break;case ns_r_notzone:fprintf(f, "Record zone does not match section zone\n");break;case ns_r_badvers:fprintf(f, "Invalid EDNS version or TSIG signature\n");break;case ns_r_badkey:fprintf(f, "Invalid key\n");break;case ns_r_badtime:fprintf(f, "Invalid time\n");break;default:fprintf(f, "Reserved (%hu)\n",(uint16_t)(h->flags & DNS_FLAGS_RCODE_MASK));}}if (mask & DNS_PRINT_QUESTION){fprintf(f, "Question (%hu):\n", h->qdcount);for (i = 0; i < h->qdcount; i++)_dns_print_question_lock(r->question[i], f, 0);}if (mask & DNS_PRINT_ANSWER){fprintf(f, "Answer (%hu):\n", h->ancount);for (i = 0; i < h->ancount; i++)_dns_print_resource_record_lock(r->answer[i], f, 0);}if (mask & DNS_PRINT_AUTHORITY){fprintf(f, "Authority (%hu):\n", h->nscount);for (i = 0; i < h->nscount; i++)_dns_print_resource_record_lock(r->authority[i], f, 0);}if (mask & DNS_PRINT_ADDITIONAL){fprintf(f, "Additional records (%hu):\n", h->arcount);for (i = 0; i < h->arcount; i++)_dns_print_resource_record_lock(r->additional[i], f, 0);}_dns_print_unlock();}static void_pdns_print_handle(pdns_handle_t *pdns, FILE *f){uint32_t i, offset;struct in_addr a;char scratch[1024];struct sockaddr *sa;res_state r;if (pdns == NULL){fprintf(f, "-nil-\n");return;}if (pdns->name == NULL) fprintf(f, "Name: -nil-\n");else fprintf(f, "Name: %s\n", pdns->name);fprintf(f, "Flags:");if (pdns->flags == 0) fprintf(f, " None\n");else {if (pdns->flags & DNS_FLAG_DEBUG) fprintf(f, " Debug");if (pdns->flags & DNS_FLAG_CHECK_RESOLVER_DIR) fprintf(f, " DirCheck");if (pdns->flags & DNS_FLAG_HAVE_IPV6_SERVER) fprintf(f, " IPv6");if (pdns->flags & DNS_FLAG_OK_TO_SKIP_AAAA) fprintf(f, " SkipAAAA");if (pdns->flags & DNS_FLAG_DEFAULT_RESOLVER) fprintf(f, " Default");fprintf(f, "\n");}r = pdns->res;if (r == NULL) return;if (r->defdname[0] != '\0') fprintf(f, "Domain: %s\n", r->defdname);fprintf(f, "Search Order: %d\n", pdns->search_order);fprintf(f, "Total Timeout: %d\n", pdns->total_timeout);fprintf(f, "Retry Timeout: %d\n", pdns->res->retrans);fprintf(f, "Retry Attempts: %d\n", pdns->res->retry);fprintf(f, "Server%s:\n", (r->nscount == 1) ? "" : "s");for (i = 0; i < r->nscount; i++){sa = get_nsaddr(r, i);offset = INET_NTOP_AF_INET_OFFSET;if (sa->sa_family == AF_INET6) offset = INET_NTOP_AF_INET6_OFFSET;fprintf(f, "  %u: %s", i, inet_ntop(sa->sa_family, (char *)sa + offset, scratch, 1024));fprintf(f, "\n");}if (pdns->search_count > 0){fprintf(f, "Search List:\n");for (i = 0; i < pdns->search_count; i++)fprintf(f, "  %u: %s\n", i, pdns->search_list[i]);}if (r->sort_list[0].addr.s_addr != 0){fprintf(f, "Sortlist:\n");for (i = 0; (r->sort_list[i].addr.s_addr != 0); i++){fprintf(f, "  %u: ", i);a.s_addr = r->sort_list[i].addr.s_addr;fprintf(f, "%s/", inet_ntoa(a));a.s_addr = r->sort_list[i].mask;fprintf(f, "%s\n", inet_ntoa(a));}}}static void_sdns_print_handle(sdns_handle_t *sdns, FILE *f){int i;if (sdns == NULL){fprintf(f, "-nil-\n");return;}for (i = 0; i < sdns->client_count; i++){fprintf(f, "DNS client %d\n", i);_pdns_print_handle(sdns->client[i], f);fprintf(f, "\n");}fprintf(f, "resolver dir mod time = %u\n", sdns->modtime);fprintf(f, "resolver dir stat time = %u\n", sdns->stattime);fprintf(f, "resolver dir stat latency = %u\n", sdns->stat_latency);}voiddns_print_handle(dns_handle_t d, FILE *f){dns_private_handle_t *dns;_dns_print_lock();if (d == NULL){fprintf(f, "-nil-\n");_dns_print_unlock();return;}dns = (dns_private_handle_t *)d;if (dns->handle_type == DNS_PRIVATE_HANDLE_TYPE_SUPER){_sdns_print_handle(dns->sdns, f);}else{_pdns_print_handle(dns->pdns, f);}_dns_print_unlock();}voiddns_all_server_addrs(dns_handle_t d, struct sockaddr ***addrs, uint32_t *count){int i, j, k, n, found;dns_private_handle_t *dns;pdns_handle_t *pdns;struct sockaddr *sa;struct sockaddr_storage **l;res_state r;*addrs = NULL;*count = 0;l = NULL;n = 0;if (d == NULL) return;dns = (dns_private_handle_t *)d;if (dns->handle_type != DNS_PRIVATE_HANDLE_TYPE_SUPER) return;if (dns->sdns == NULL) return;/* Just to initialize / validate clients */i = dns_search_list_count(d);for (i = 0; i < dns->sdns->client_count; i++){pdns = dns->sdns->client[i];if (pdns == NULL) continue;r = pdns->res;if (r == NULL) continue;for (j = 0; j < r->nscount; j++){sa = get_nsaddr(r, j);found = 0;for (k = 0; (found == 0) && (k < n); k++){if (memcmp(l[k], sa, sa->sa_len) == 0) found = 1;}if (found == 1) continue;if (n == 0){l = (struct sockaddr_storage **)calloc(1, sizeof(struct sockaddr_storage *));}else{l = (struct sockaddr_storage **)reallocf(l, (n + 1) * sizeof(struct sockaddr_storage *));}if (l == NULL) return;l[n] = (struct sockaddr_storage *)calloc(1, sizeof(struct sockaddr_storage));if (l[n] == NULL) return;memset(l[n], 0, sizeof(struct sockaddr_storage));memcpy(l[n], sa, sa->sa_len);n++;}}*addrs = (struct sockaddr **)l;*count = n;}intdns_res_once(struct sockaddr *server, struct timeval *timeout, int options, const char *name, int class, int type, u_char *res, int *reslen){res_state statp;int n, fromlen, status;struct sockaddr_storage from;u_char buf[MAXPACKET];if (server == NULL) return DNS_RES_STATUS_INVALID_ARGUMENT;if (name == NULL) return DNS_RES_STATUS_INVALID_ARGUMENT;if (res == NULL) return DNS_RES_STATUS_INVALID_ARGUMENT;if (reslen == NULL) return DNS_RES_STATUS_INVALID_ARGUMENT;fromlen = sizeof(struct sockaddr_storage);statp = res_state_new();statp->retry = 1;statp->options = options;statp->id = res_randomid();if (timeout == NULL) statp->retrans = 5;else statp->retrans = timeout->tv_sec;statp->ndots = 1;statp->_vcsock = -1;statp->nscount = 1;strcpy(statp->_u._ext.ext->nsuffix, "ip6.arpa");strcpy(statp->_u._ext.ext->nsuffix2, "ip6.int");strcpy(statp->_u._ext.ext->bsuffix, "ip6.arpa");if (server->sa_family == AF_INET6){memcpy(&(statp->_u._ext.ext->nsaddrs[0]), server, sizeof(struct sockaddr_in6));statp->nsaddr_list[0].sin_family = 0;}else{memcpy(&(statp->_u._ext.ext->nsaddrs[0]), server, sizeof(struct sockaddr_in));memcpy(&(statp->nsaddr_list[0]), server, sizeof(struct sockaddr_in));}n = res_nmkquery(statp, ns_o_query, name, class, type, NULL, 0, NULL, buf, sizeof(buf));status = dns_res_send(statp, buf, n, res, reslen, (struct sockaddr *)&from, &fromlen);res_client_close(statp);return status;}

原文地址：http://www.opensource.apple.com/source/libresolv/libresolv-51/dns_util.c?txt