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ares_init.c
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ares_init.c
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/* Copyright 1998 by the Massachusetts Institute of Technology.
* Copyright (C) 2007-2013 by Daniel Stenberg
*
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting
* documentation, and that the name of M.I.T. not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is"
* without express or implied warranty.
*/
#include "ares_setup.h"
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_ARPA_NAMESER_H
# include <arpa/nameser.h>
#else
# include "nameser.h"
#endif
#ifdef HAVE_ARPA_NAMESER_COMPAT_H
# include <arpa/nameser_compat.h>
#endif
#if defined(ANDROID) || defined(__ANDROID__)
#include <sys/system_properties.h>
/* From the Bionic sources */
#define DNS_PROP_NAME_PREFIX "net.dns"
#define MAX_DNS_PROPERTIES 8
#endif
#include "ares.h"
#include "ares_inet_net_pton.h"
#include "ares_library_init.h"
#include "ares_nowarn.h"
#include "ares_platform.h"
#include "ares_private.h"
#ifdef WATT32
#undef WIN32 /* Redefined in MingW/MSVC headers */
#endif
static int init_by_options(ares_channel channel,
const struct ares_options *options,
int optmask);
static int init_by_environment(ares_channel channel);
static int init_by_resolv_conf(ares_channel channel);
static int init_by_defaults(ares_channel channel);
#ifndef WATT32
static int config_nameserver(struct server_state **servers, int *nservers,
char *str);
#endif
static int set_search(ares_channel channel, const char *str);
static int set_options(ares_channel channel, const char *str);
static const char *try_option(const char *p, const char *q, const char *opt);
static int init_id_key(rc4_key* key,int key_data_len);
#if !defined(WIN32) && !defined(WATT32) && \
!defined(ANDROID) && !defined(__ANDROID__)
static int sortlist_alloc(struct apattern **sortlist, int *nsort,
struct apattern *pat);
static int ip_addr(const char *s, ssize_t len, struct in_addr *addr);
static void natural_mask(struct apattern *pat);
static int config_domain(ares_channel channel, char *str);
static int config_lookup(ares_channel channel, const char *str,
const char *bindch, const char *filech);
static int config_sortlist(struct apattern **sortlist, int *nsort,
const char *str);
static char *try_config(char *s, const char *opt, char scc);
#endif
#define ARES_CONFIG_CHECK(x) (x->lookups && x->nsort > -1 && \
x->nservers > -1 && \
x->ndomains > -1 && \
x->ndots > -1 && x->timeout > -1 && \
x->tries > -1)
int ares_init(ares_channel *channelptr)
{
return ares_init_options(channelptr, NULL, 0);
}
int ares_init_options(ares_channel *channelptr, struct ares_options *options,
int optmask)
{
ares_channel channel;
int i;
int status = ARES_SUCCESS;
struct timeval now;
#ifdef CURLDEBUG
const char *env = getenv("CARES_MEMDEBUG");
if (env)
curl_memdebug(env);
env = getenv("CARES_MEMLIMIT");
if (env) {
char *endptr;
long num = strtol(env, &endptr, 10);
if((endptr != env) && (endptr == env + strlen(env)) && (num > 0))
curl_memlimit(num);
}
#endif
if (ares_library_initialized() != ARES_SUCCESS)
return ARES_ENOTINITIALIZED;
channel = malloc(sizeof(struct ares_channeldata));
if (!channel) {
*channelptr = NULL;
return ARES_ENOMEM;
}
now = ares__tvnow();
/* Set everything to distinguished values so we know they haven't
* been set yet.
*/
channel->flags = -1;
channel->timeout = -1;
channel->tries = -1;
channel->ndots = -1;
channel->rotate = -1;
channel->udp_port = -1;
channel->tcp_port = -1;
channel->ednspsz = -1;
channel->socket_send_buffer_size = -1;
channel->socket_receive_buffer_size = -1;
channel->nservers = -1;
channel->ndomains = -1;
channel->nsort = -1;
channel->tcp_connection_generation = 0;
channel->lookups = NULL;
channel->domains = NULL;
channel->sortlist = NULL;
channel->servers = NULL;
channel->sock_state_cb = NULL;
channel->sock_state_cb_data = NULL;
channel->sock_create_cb = NULL;
channel->sock_create_cb_data = NULL;
channel->last_server = 0;
channel->last_timeout_processed = (time_t)now.tv_sec;
memset(&channel->local_dev_name, 0, sizeof(channel->local_dev_name));
channel->local_ip4 = 0;
memset(&channel->local_ip6, 0, sizeof(channel->local_ip6));
/* Initialize our lists of queries */
ares__init_list_head(&(channel->all_queries));
for (i = 0; i < ARES_QID_TABLE_SIZE; i++)
{
ares__init_list_head(&(channel->queries_by_qid[i]));
}
for (i = 0; i < ARES_TIMEOUT_TABLE_SIZE; i++)
{
ares__init_list_head(&(channel->queries_by_timeout[i]));
}
/* Initialize configuration by each of the four sources, from highest
* precedence to lowest.
*/
if (status == ARES_SUCCESS) {
status = init_by_options(channel, options, optmask);
if (status != ARES_SUCCESS)
DEBUGF(fprintf(stderr, "Error: init_by_options failed: %s\n",
ares_strerror(status)));
}
if (status == ARES_SUCCESS) {
status = init_by_environment(channel);
if (status != ARES_SUCCESS)
DEBUGF(fprintf(stderr, "Error: init_by_environment failed: %s\n",
ares_strerror(status)));
}
if (status == ARES_SUCCESS) {
status = init_by_resolv_conf(channel);
if (status != ARES_SUCCESS)
DEBUGF(fprintf(stderr, "Error: init_by_resolv_conf failed: %s\n",
ares_strerror(status)));
}
/*
* No matter what failed or succeeded, seed defaults to provide
* useful behavior for things that we missed.
*/
status = init_by_defaults(channel);
if (status != ARES_SUCCESS)
DEBUGF(fprintf(stderr, "Error: init_by_defaults failed: %s\n",
ares_strerror(status)));
/* Generate random key */
if (status == ARES_SUCCESS) {
status = init_id_key(&channel->id_key, ARES_ID_KEY_LEN);
if (status == ARES_SUCCESS)
channel->next_id = ares__generate_new_id(&channel->id_key);
else
DEBUGF(fprintf(stderr, "Error: init_id_key failed: %s\n",
ares_strerror(status)));
}
if (status != ARES_SUCCESS)
{
/* Something failed; clean up memory we may have allocated. */
if (channel->servers)
free(channel->servers);
if (channel->domains)
{
for (i = 0; i < channel->ndomains; i++)
free(channel->domains[i]);
free(channel->domains);
}
if (channel->sortlist)
free(channel->sortlist);
if(channel->lookups)
free(channel->lookups);
free(channel);
return status;
}
/* Trim to one server if ARES_FLAG_PRIMARY is set. */
if ((channel->flags & ARES_FLAG_PRIMARY) && channel->nservers > 1)
channel->nservers = 1;
ares__init_servers_state(channel);
*channelptr = channel;
return ARES_SUCCESS;
}
/* ares_dup() duplicates a channel handle with all its options and returns a
new channel handle */
int ares_dup(ares_channel *dest, ares_channel src)
{
struct ares_options opts;
struct ares_addr_node *servers;
int ipv6_nservers = 0;
int i, rc;
int optmask;
*dest = NULL; /* in case of failure return NULL explicitly */
/* First get the options supported by the old ares_save_options() function,
which is most of them */
rc = ares_save_options(src, &opts, &optmask);
if(rc)
return rc;
/* Then create the new channel with those options */
rc = ares_init_options(dest, &opts, optmask);
/* destroy the options copy to not leak any memory */
ares_destroy_options(&opts);
if(rc)
return rc;
/* Now clone the options that ares_save_options() doesn't support. */
(*dest)->sock_create_cb = src->sock_create_cb;
(*dest)->sock_create_cb_data = src->sock_create_cb_data;
strncpy((*dest)->local_dev_name, src->local_dev_name,
sizeof(src->local_dev_name));
(*dest)->local_ip4 = src->local_ip4;
memcpy((*dest)->local_ip6, src->local_ip6, sizeof(src->local_ip6));
/* Full name server cloning required when not all are IPv4 */
for (i = 0; i < src->nservers; i++)
{
if (src->servers[i].addr.family != AF_INET) {
ipv6_nservers++;
break;
}
}
if (ipv6_nservers) {
rc = ares_get_servers(src, &servers);
if (rc != ARES_SUCCESS)
return rc;
rc = ares_set_servers(*dest, servers);
ares_free_data(servers);
if (rc != ARES_SUCCESS)
return rc;
}
return ARES_SUCCESS; /* everything went fine */
}
/* Save options from initialized channel */
int ares_save_options(ares_channel channel, struct ares_options *options,
int *optmask)
{
int i, j;
int ipv4_nservers = 0;
/* Zero everything out */
memset(options, 0, sizeof(struct ares_options));
if (!ARES_CONFIG_CHECK(channel))
return ARES_ENODATA;
/* Traditionally the optmask wasn't saved in the channel struct so it was
recreated here. ROTATE is the first option that has no struct field of
its own in the public config struct */
(*optmask) = (ARES_OPT_FLAGS|ARES_OPT_TRIES|ARES_OPT_NDOTS|
ARES_OPT_UDP_PORT|ARES_OPT_TCP_PORT|ARES_OPT_SOCK_STATE_CB|
ARES_OPT_SERVERS|ARES_OPT_DOMAINS|ARES_OPT_LOOKUPS|
ARES_OPT_SORTLIST|ARES_OPT_TIMEOUTMS) |
(channel->optmask & ARES_OPT_ROTATE);
/* Copy easy stuff */
options->flags = channel->flags;
/* We return full millisecond resolution but that's only because we don't
set the ARES_OPT_TIMEOUT anymore, only the new ARES_OPT_TIMEOUTMS */
options->timeout = channel->timeout;
options->tries = channel->tries;
options->ndots = channel->ndots;
options->udp_port = ntohs(aresx_sitous(channel->udp_port));
options->tcp_port = ntohs(aresx_sitous(channel->tcp_port));
options->sock_state_cb = channel->sock_state_cb;
options->sock_state_cb_data = channel->sock_state_cb_data;
/* Copy IPv4 servers */
if (channel->nservers) {
for (i = 0; i < channel->nservers; i++)
{
if (channel->servers[i].addr.family == AF_INET)
ipv4_nservers++;
}
if (ipv4_nservers) {
options->servers = malloc(ipv4_nservers * sizeof(struct in_addr));
if (!options->servers)
return ARES_ENOMEM;
for (i = j = 0; i < channel->nservers; i++)
{
if (channel->servers[i].addr.family == AF_INET)
memcpy(&options->servers[j++],
&channel->servers[i].addr.addrV4,
sizeof(channel->servers[i].addr.addrV4));
}
}
}
options->nservers = ipv4_nservers;
/* copy domains */
if (channel->ndomains) {
options->domains = malloc(channel->ndomains * sizeof(char *));
if (!options->domains)
return ARES_ENOMEM;
for (i = 0; i < channel->ndomains; i++)
{
options->ndomains = i;
options->domains[i] = strdup(channel->domains[i]);
if (!options->domains[i])
return ARES_ENOMEM;
}
}
options->ndomains = channel->ndomains;
/* copy lookups */
if (channel->lookups) {
options->lookups = strdup(channel->lookups);
if (!options->lookups && channel->lookups)
return ARES_ENOMEM;
}
/* copy sortlist */
if (channel->nsort) {
options->sortlist = malloc(channel->nsort * sizeof(struct apattern));
if (!options->sortlist)
return ARES_ENOMEM;
for (i = 0; i < channel->nsort; i++)
options->sortlist[i] = channel->sortlist[i];
}
options->nsort = channel->nsort;
return ARES_SUCCESS;
}
static int init_by_options(ares_channel channel,
const struct ares_options *options,
int optmask)
{
int i;
/* Easy stuff. */
if ((optmask & ARES_OPT_FLAGS) && channel->flags == -1)
channel->flags = options->flags;
if ((optmask & ARES_OPT_TIMEOUTMS) && channel->timeout == -1)
channel->timeout = options->timeout;
else if ((optmask & ARES_OPT_TIMEOUT) && channel->timeout == -1)
channel->timeout = options->timeout * 1000;
if ((optmask & ARES_OPT_TRIES) && channel->tries == -1)
channel->tries = options->tries;
if ((optmask & ARES_OPT_NDOTS) && channel->ndots == -1)
channel->ndots = options->ndots;
if ((optmask & ARES_OPT_ROTATE) && channel->rotate == -1)
channel->rotate = 1;
if ((optmask & ARES_OPT_UDP_PORT) && channel->udp_port == -1)
channel->udp_port = htons(options->udp_port);
if ((optmask & ARES_OPT_TCP_PORT) && channel->tcp_port == -1)
channel->tcp_port = htons(options->tcp_port);
if ((optmask & ARES_OPT_SOCK_STATE_CB) && channel->sock_state_cb == NULL)
{
channel->sock_state_cb = options->sock_state_cb;
channel->sock_state_cb_data = options->sock_state_cb_data;
}
if ((optmask & ARES_OPT_SOCK_SNDBUF)
&& channel->socket_send_buffer_size == -1)
channel->socket_send_buffer_size = options->socket_send_buffer_size;
if ((optmask & ARES_OPT_SOCK_RCVBUF)
&& channel->socket_receive_buffer_size == -1)
channel->socket_receive_buffer_size = options->socket_receive_buffer_size;
if ((optmask & ARES_OPT_EDNSPSZ) && channel->ednspsz == -1)
channel->ednspsz = options->ednspsz;
/* Copy the IPv4 servers, if given. */
if ((optmask & ARES_OPT_SERVERS) && channel->nservers == -1)
{
/* Avoid zero size allocations at any cost */
if (options->nservers > 0)
{
channel->servers =
malloc(options->nservers * sizeof(struct server_state));
if (!channel->servers)
return ARES_ENOMEM;
for (i = 0; i < options->nservers; i++)
{
channel->servers[i].addr.family = AF_INET;
memcpy(&channel->servers[i].addr.addrV4,
&options->servers[i],
sizeof(channel->servers[i].addr.addrV4));
}
}
channel->nservers = options->nservers;
}
/* Copy the domains, if given. Keep channel->ndomains consistent so
* we can clean up in case of error.
*/
if ((optmask & ARES_OPT_DOMAINS) && channel->ndomains == -1)
{
/* Avoid zero size allocations at any cost */
if (options->ndomains > 0)
{
channel->domains = malloc(options->ndomains * sizeof(char *));
if (!channel->domains)
return ARES_ENOMEM;
for (i = 0; i < options->ndomains; i++)
{
channel->ndomains = i;
channel->domains[i] = strdup(options->domains[i]);
if (!channel->domains[i])
return ARES_ENOMEM;
}
}
channel->ndomains = options->ndomains;
}
/* Set lookups, if given. */
if ((optmask & ARES_OPT_LOOKUPS) && !channel->lookups)
{
channel->lookups = strdup(options->lookups);
if (!channel->lookups)
return ARES_ENOMEM;
}
/* copy sortlist */
if ((optmask & ARES_OPT_SORTLIST) && (channel->nsort == -1) &&
(options->nsort>0)) {
channel->sortlist = malloc(options->nsort * sizeof(struct apattern));
if (!channel->sortlist)
return ARES_ENOMEM;
for (i = 0; i < options->nsort; i++)
channel->sortlist[i] = options->sortlist[i];
channel->nsort = options->nsort;
}
channel->optmask = optmask;
return ARES_SUCCESS;
}
static int init_by_environment(ares_channel channel)
{
const char *localdomain, *res_options;
int status;
localdomain = getenv("LOCALDOMAIN");
if (localdomain && channel->ndomains == -1)
{
status = set_search(channel, localdomain);
if (status != ARES_SUCCESS)
return status;
}
res_options = getenv("RES_OPTIONS");
if (res_options)
{
status = set_options(channel, res_options);
if (status != ARES_SUCCESS)
return status;
}
return ARES_SUCCESS;
}
#ifdef WIN32
/*
* get_REG_SZ()
*
* Given a 'hKey' handle to an open registry key and a 'leafKeyName' pointer
* to the name of the registry leaf key to be queried, fetch it's string
* value and return a pointer in *outptr to a newly allocated memory area
* holding it as a null-terminated string.
*
* Returns 0 and nullifies *outptr upon inability to return a string value.
*
* Returns 1 and sets *outptr when returning a dynamically allocated string.
*
* Supported on Windows NT 3.5 and newer.
*/
static int get_REG_SZ(HKEY hKey, const char *leafKeyName, char **outptr)
{
DWORD size = 0;
int res;
*outptr = NULL;
/* Find out size of string stored in registry */
res = RegQueryValueEx(hKey, leafKeyName, 0, NULL, NULL, &size);
if ((res != ERROR_SUCCESS && res != ERROR_MORE_DATA) || !size)
return 0;
/* Allocate buffer of indicated size plus one given that string
might have been stored without null termination */
*outptr = malloc(size+1);
if (!*outptr)
return 0;
/* Get the value for real */
res = RegQueryValueEx(hKey, leafKeyName, 0, NULL,
(unsigned char *)*outptr, &size);
if ((res != ERROR_SUCCESS) || (size == 1))
{
free(*outptr);
*outptr = NULL;
return 0;
}
/* Null terminate buffer allways */
*(*outptr + size) = '\0';
return 1;
}
/*
* get_REG_SZ_9X()
*
* Functionally identical to get_REG_SZ()
*
* Supported on Windows 95, 98 and ME.
*/
static int get_REG_SZ_9X(HKEY hKey, const char *leafKeyName, char **outptr)
{
DWORD dataType = 0;
DWORD size = 0;
int res;
*outptr = NULL;
/* Find out size of string stored in registry */
res = RegQueryValueEx(hKey, leafKeyName, 0, &dataType, NULL, &size);
if ((res != ERROR_SUCCESS && res != ERROR_MORE_DATA) || !size)
return 0;
/* Allocate buffer of indicated size plus one given that string
might have been stored without null termination */
*outptr = malloc(size+1);
if (!*outptr)
return 0;
/* Get the value for real */
res = RegQueryValueEx(hKey, leafKeyName, 0, &dataType,
(unsigned char *)*outptr, &size);
if ((res != ERROR_SUCCESS) || (size == 1))
{
free(*outptr);
*outptr = NULL;
return 0;
}
/* Null terminate buffer allways */
*(*outptr + size) = '\0';
return 1;
}
/*
* get_enum_REG_SZ()
*
* Given a 'hKeyParent' handle to an open registry key and a 'leafKeyName'
* pointer to the name of the registry leaf key to be queried, parent key
* is enumerated searching in child keys for given leaf key name and its
* associated string value. When located, this returns a pointer in *outptr
* to a newly allocated memory area holding it as a null-terminated string.
*
* Returns 0 and nullifies *outptr upon inability to return a string value.
*
* Returns 1 and sets *outptr when returning a dynamically allocated string.
*
* Supported on Windows NT 3.5 and newer.
*/
static int get_enum_REG_SZ(HKEY hKeyParent, const char *leafKeyName,
char **outptr)
{
char enumKeyName[256];
DWORD enumKeyNameBuffSize;
DWORD enumKeyIdx = 0;
HKEY hKeyEnum;
int gotString;
int res;
*outptr = NULL;
for(;;)
{
enumKeyNameBuffSize = sizeof(enumKeyName);
res = RegEnumKeyEx(hKeyParent, enumKeyIdx++, enumKeyName,
&enumKeyNameBuffSize, 0, NULL, NULL, NULL);
if (res != ERROR_SUCCESS)
break;
res = RegOpenKeyEx(hKeyParent, enumKeyName, 0, KEY_QUERY_VALUE,
&hKeyEnum);
if (res != ERROR_SUCCESS)
continue;
gotString = get_REG_SZ(hKeyEnum, leafKeyName, outptr);
RegCloseKey(hKeyEnum);
if (gotString)
break;
}
if (!*outptr)
return 0;
return 1;
}
/*
* get_DNS_Registry_9X()
*
* Functionally identical to get_DNS_Registry()
*
* Implementation supports Windows 95, 98 and ME.
*/
static int get_DNS_Registry_9X(char **outptr)
{
HKEY hKey_VxD_MStcp;
int gotString;
int res;
*outptr = NULL;
res = RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_9X, 0, KEY_READ,
&hKey_VxD_MStcp);
if (res != ERROR_SUCCESS)
return 0;
gotString = get_REG_SZ_9X(hKey_VxD_MStcp, NAMESERVER, outptr);
RegCloseKey(hKey_VxD_MStcp);
if (!gotString || !*outptr)
return 0;
return 1;
}
/*
* get_DNS_Registry_NT()
*
* Functionally identical to get_DNS_Registry()
*
* Refs: Microsoft Knowledge Base articles KB120642 and KB314053.
*
* Implementation supports Windows NT 3.5 and newer.
*/
static int get_DNS_Registry_NT(char **outptr)
{
HKEY hKey_Interfaces = NULL;
HKEY hKey_Tcpip_Parameters;
int gotString;
int res;
*outptr = NULL;
res = RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ,
&hKey_Tcpip_Parameters);
if (res != ERROR_SUCCESS)
return 0;
/*
** Global DNS settings override adapter specific parameters when both
** are set. Additionally static DNS settings override DHCP-configured
** parameters when both are set.
*/
/* Global DNS static parameters */
gotString = get_REG_SZ(hKey_Tcpip_Parameters, NAMESERVER, outptr);
if (gotString)
goto done;
/* Global DNS DHCP-configured parameters */
gotString = get_REG_SZ(hKey_Tcpip_Parameters, DHCPNAMESERVER, outptr);
if (gotString)
goto done;
/* Try adapter specific parameters */
res = RegOpenKeyEx(hKey_Tcpip_Parameters, "Interfaces", 0,
KEY_QUERY_VALUE | KEY_ENUMERATE_SUB_KEYS,
&hKey_Interfaces);
if (res != ERROR_SUCCESS)
{
hKey_Interfaces = NULL;
goto done;
}
/* Adapter specific DNS static parameters */
gotString = get_enum_REG_SZ(hKey_Interfaces, NAMESERVER, outptr);
if (gotString)
goto done;
/* Adapter specific DNS DHCP-configured parameters */
gotString = get_enum_REG_SZ(hKey_Interfaces, DHCPNAMESERVER, outptr);
done:
if (hKey_Interfaces)
RegCloseKey(hKey_Interfaces);
RegCloseKey(hKey_Tcpip_Parameters);
if (!gotString || !*outptr)
return 0;
return 1;
}
/*
* get_DNS_Registry()
*
* Locates DNS info in the registry. When located, this returns a pointer
* in *outptr to a newly allocated memory area holding a null-terminated
* string with a space or comma seperated list of DNS IP addresses.
*
* Returns 0 and nullifies *outptr upon inability to return DNSes string.
*
* Returns 1 and sets *outptr when returning a dynamically allocated string.
*/
static int get_DNS_Registry(char **outptr)
{
win_platform platform;
int gotString = 0;
*outptr = NULL;
platform = ares__getplatform();
if (platform == WIN_NT)
gotString = get_DNS_Registry_NT(outptr);
else if (platform == WIN_9X)
gotString = get_DNS_Registry_9X(outptr);
if (!gotString)
return 0;
return 1;
}
/*
* commajoin()
*
* RTF code.
*/
static void commajoin(char **dst, const char *src)
{
char *tmp;
if (*dst)
{
tmp = malloc(strlen(*dst) + strlen(src) + 2);
if (!tmp)
return;
sprintf(tmp, "%s,%s", *dst, src);
free(*dst);
*dst = tmp;
}
else
{
*dst = malloc(strlen(src) + 1);
if (!*dst)
return;
strcpy(*dst, src);
}
}
/*
* get_DNS_NetworkParams()
*
* Locates DNS info using GetNetworkParams() function from the Internet
* Protocol Helper (IP Helper) API. When located, this returns a pointer
* in *outptr to a newly allocated memory area holding a null-terminated
* string with a space or comma seperated list of DNS IP addresses.
*
* Returns 0 and nullifies *outptr upon inability to return DNSes string.
*
* Returns 1 and sets *outptr when returning a dynamically allocated string.
*
* Implementation supports Windows 98 and newer.
*
* Note: Ancient PSDK required in order to build a W98 target.
*/
static int get_DNS_NetworkParams(char **outptr)
{
FIXED_INFO *fi, *newfi;
struct ares_addr namesrvr;
char *txtaddr;
IP_ADDR_STRING *ipAddr;
int res;
DWORD size = sizeof (*fi);
*outptr = NULL;
/* Verify run-time availability of GetNetworkParams() */
if (ares_fpGetNetworkParams == ZERO_NULL)
return 0;
fi = malloc(size);
if (!fi)
return 0;
res = (*ares_fpGetNetworkParams) (fi, &size);
if ((res != ERROR_BUFFER_OVERFLOW) && (res != ERROR_SUCCESS))
goto done;
newfi = realloc(fi, size);
if (!newfi)
goto done;
fi = newfi;
res = (*ares_fpGetNetworkParams) (fi, &size);
if (res != ERROR_SUCCESS)
goto done;
for (ipAddr = &fi->DnsServerList; ipAddr; ipAddr = ipAddr->Next)
{
txtaddr = &ipAddr->IpAddress.String[0];
/* Validate converting textual address to binary format. */
if (ares_inet_pton(AF_INET, txtaddr, &namesrvr.addrV4) == 1)
{
if ((namesrvr.addrV4.S_un.S_addr == INADDR_ANY) ||
(namesrvr.addrV4.S_un.S_addr == INADDR_NONE))
continue;
}
else if (ares_inet_pton(AF_INET6, txtaddr, &namesrvr.addrV6) == 1)
{
if (memcmp(&namesrvr.addrV6, &ares_in6addr_any,
sizeof(namesrvr.addrV6)) == 0)
continue;
}
else
continue;
commajoin(outptr, txtaddr);
if (!*outptr)
break;
}
done:
if (fi)
free(fi);
if (!*outptr)
return 0;
return 1;
}
/*
* get_DNS_AdaptersAddresses()
*
* Locates DNS info using GetAdaptersAddresses() function from the Internet
* Protocol Helper (IP Helper) API. When located, this returns a pointer
* in *outptr to a newly allocated memory area holding a null-terminated
* string with a space or comma seperated list of DNS IP addresses.
*
* Returns 0 and nullifies *outptr upon inability to return DNSes string.
*
* Returns 1 and sets *outptr when returning a dynamically allocated string.
*
* Implementation supports Windows XP and newer.
*/
#define IPAA_INITIAL_BUF_SZ 15 * 1024
#define IPAA_MAX_TRIES 3
static int get_DNS_AdaptersAddresses(char **outptr)
{
IP_ADAPTER_DNS_SERVER_ADDRESS *ipaDNSAddr;
IP_ADAPTER_ADDRESSES *ipaa, *newipaa, *ipaaEntry;
ULONG ReqBufsz = IPAA_INITIAL_BUF_SZ;
ULONG Bufsz = IPAA_INITIAL_BUF_SZ;
ULONG AddrFlags = 0;
int trying = IPAA_MAX_TRIES;
int res;
union {
struct sockaddr *sa;
struct sockaddr_in *sa4;
struct sockaddr_in6 *sa6;
} namesrvr;
char txtaddr[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
*outptr = NULL;
/* Verify run-time availability of GetAdaptersAddresses() */
if (ares_fpGetAdaptersAddresses == ZERO_NULL)
return 0;
ipaa = malloc(Bufsz);
if (!ipaa)
return 0;
/* Usually this call suceeds with initial buffer size */
res = (*ares_fpGetAdaptersAddresses) (AF_UNSPEC, AddrFlags, NULL,
ipaa, &ReqBufsz);
if ((res != ERROR_BUFFER_OVERFLOW) && (res != ERROR_SUCCESS))
goto done;
while ((res == ERROR_BUFFER_OVERFLOW) && (--trying))
{
if (Bufsz < ReqBufsz)
{
newipaa = realloc(ipaa, ReqBufsz);
if (!newipaa)
goto done;
Bufsz = ReqBufsz;
ipaa = newipaa;
}
res = (*ares_fpGetAdaptersAddresses) (AF_UNSPEC, AddrFlags, NULL,
ipaa, &ReqBufsz);
if (res == ERROR_SUCCESS)
break;
}
if (res != ERROR_SUCCESS)
goto done;
for (ipaaEntry = ipaa; ipaaEntry; ipaaEntry = ipaaEntry->Next)
{
for (ipaDNSAddr = ipaaEntry->FirstDnsServerAddress;
ipaDNSAddr;
ipaDNSAddr = ipaDNSAddr->Next)
{
namesrvr.sa = ipaDNSAddr->Address.lpSockaddr;
if (namesrvr.sa->sa_family == AF_INET)
{
if ((namesrvr.sa4->sin_addr.S_un.S_addr == INADDR_ANY) ||
(namesrvr.sa4->sin_addr.S_un.S_addr == INADDR_NONE))
continue;
if (! ares_inet_ntop(AF_INET, &namesrvr.sa4->sin_addr,
txtaddr, sizeof(txtaddr)))
continue;
}
else if (namesrvr.sa->sa_family == AF_INET6)
{
if (memcmp(&namesrvr.sa6->sin6_addr, &ares_in6addr_any,