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A C library for asynchronous DNS requests (grpc依赖)
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c-ares/ares_init.c

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/* $Id$ */
/* Copyright 1998 by the Massachusetts Institute of Technology.
* Copyright (C) 2007-2008 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 "setup.h"
#if defined(WIN32) && !defined(WATT32)
#include <iphlpapi.h>
#include <malloc.h>
#endif
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.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
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include <errno.h>
#include "ares.h"
#include "inet_net_pton.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);
static int config_nameserver(struct server_state **servers, int *nservers,
char *str);
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);
#ifndef WIN32
static int sortlist_alloc(struct apattern **sortlist, int *nsort, struct apattern *pat);
static int ip_addr(const char *s, int 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);
#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 server_state *server;
struct timeval now;
#ifdef CURLDEBUG
const char *env = getenv("CARES_MEMDEBUG");
if (env)
curl_memdebug(env);
env = getenv("CARES_MEMLIMIT");
if (env)
curl_memlimit(atoi(env));
#endif
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->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->last_server = 0;
channel->last_timeout_processed = (time_t)now.tv_sec;
/* 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)));
}
if (status == ARES_SUCCESS) {
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;
/* Initialize server states. */
for (i = 0; i < channel->nservers; i++)
{
server = &channel->servers[i];
server->udp_socket = ARES_SOCKET_BAD;
server->tcp_socket = ARES_SOCKET_BAD;
server->tcp_connection_generation = ++channel->tcp_connection_generation;
server->tcp_lenbuf_pos = 0;
server->tcp_buffer = NULL;
server->qhead = NULL;
server->qtail = NULL;
ares__init_list_head(&(server->queries_to_server));
server->channel = channel;
server->is_broken = 0;
}
*channelptr = channel;
return ARES_SUCCESS;
}
/* Save options from initialized channel */
int ares_save_options(ares_channel channel, struct ares_options *options,
int *optmask)
{
int i;
/* Zero everything out */
memset(options, 0, sizeof(struct ares_options));
if (!ARES_CONFIG_CHECK(channel))
return ARES_ENODATA;
(*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);
/* 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 = (unsigned short)channel->udp_port;
options->tcp_port = (unsigned short)channel->tcp_port;
options->sock_state_cb = channel->sock_state_cb;
options->sock_state_cb_data = channel->sock_state_cb_data;
/* Copy servers */
if (channel->nservers) {
options->servers =
malloc(channel->nservers * sizeof(struct server_state));
if (!options->servers && channel->nservers != 0)
return ARES_ENOMEM;
for (i = 0; i < channel->nservers; i++)
options->servers[i] = channel->servers[i].addr;
}
options->nservers = channel->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++)
{
memcpy(&(options->sortlist[i]), &(channel->sortlist[i]),
sizeof(struct apattern));
}
}
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 = options->rotate;
if ((optmask & ARES_OPT_UDP_PORT) && channel->udp_port == -1)
channel->udp_port = options->udp_port;
if ((optmask & ARES_OPT_TCP_PORT) && channel->tcp_port == -1)
channel->tcp_port = 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;
/* Copy the 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 = options->servers[i];
}
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)
{
channel->sortlist = malloc(options->nsort * sizeof(struct apattern));
if (!channel->sortlist)
return ARES_ENOMEM;
for (i = 0; i < options->nsort; i++)
{
memcpy(&(channel->sortlist[i]), &(options->sortlist[i]), sizeof(struct apattern));
}
channel->nsort = options->nsort;
}
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
/*
* Warning: returns a dynamically allocated buffer, the user MUST
* use free() if the function returns 1
*/
static int get_res_nt(HKEY hKey, const char *subkey, char **obuf)
{
/* Test for the size we need */
DWORD size = 0;
int result;
result = RegQueryValueEx(hKey, subkey, 0, NULL, NULL, &size);
if ((result != ERROR_SUCCESS && result != ERROR_MORE_DATA) || !size)
return 0;
*obuf = malloc(size+1);
if (!*obuf)
return 0;
if (RegQueryValueEx(hKey, subkey, 0, NULL,
(LPBYTE)*obuf, &size) != ERROR_SUCCESS)
{
free(*obuf);
return 0;
}
if (size == 1)
{
free(*obuf);
return 0;
}
return 1;
}
static int get_res_interfaces_nt(HKEY hKey, const char *subkey, char **obuf)
{
char enumbuf[39]; /* GUIDs are 38 chars + 1 for NULL */
DWORD enum_size = 39;
int idx = 0;
HKEY hVal;
while (RegEnumKeyEx(hKey, idx++, enumbuf, &enum_size, 0,
NULL, NULL, NULL) != ERROR_NO_MORE_ITEMS)
{
int rc;
enum_size = 39;
if (RegOpenKeyEx(hKey, enumbuf, 0, KEY_QUERY_VALUE, &hVal) !=
ERROR_SUCCESS)
continue;
rc = get_res_nt(hVal, subkey, obuf);
RegCloseKey(hVal);
if (rc)
return 1;
}
return 0;
}
static int get_iphlpapi_dns_info (char *ret_buf, size_t ret_size)
{
FIXED_INFO *fi = alloca (sizeof(*fi));
DWORD size = sizeof (*fi);
typedef DWORD (WINAPI* get_net_param_func) (FIXED_INFO*, DWORD*);
get_net_param_func fpGetNetworkParams; /* available only on Win-98/2000+ */
HMODULE handle;
IP_ADDR_STRING *ipAddr;
int i, count = 0;
int debug = 0;
size_t ip_size = sizeof("255.255.255.255,")-1;
size_t left = ret_size;
char *ret = ret_buf;
HRESULT res;
if (!fi)
return (0);
handle = LoadLibrary ("iphlpapi.dll");
if (!handle)
return (0);
fpGetNetworkParams = (get_net_param_func) GetProcAddress (handle, "GetNetworkParams");
if (!fpGetNetworkParams)
goto quit;
res = (*fpGetNetworkParams) (fi, &size);
if ((res != ERROR_BUFFER_OVERFLOW) && (res != ERROR_SUCCESS))
goto quit;
fi = alloca (size);
if (!fi || (*fpGetNetworkParams) (fi, &size) != ERROR_SUCCESS)
goto quit;
if (debug)
{
printf ("Host Name: %s\n", fi->HostName);
printf ("Domain Name: %s\n", fi->DomainName);
printf ("DNS Servers:\n"
" %s (primary)\n", fi->DnsServerList.IpAddress.String);
}
if (strlen(fi->DnsServerList.IpAddress.String) > 0 &&
inet_addr(fi->DnsServerList.IpAddress.String) != INADDR_NONE &&
left > ip_size)
{
ret += sprintf (ret, "%s,", fi->DnsServerList.IpAddress.String);
left -= ret - ret_buf;
count++;
}
for (i = 0, ipAddr = fi->DnsServerList.Next; ipAddr && left > ip_size;
ipAddr = ipAddr->Next, i++)
{
if (inet_addr(ipAddr->IpAddress.String) != INADDR_NONE)
{
ret += sprintf (ret, "%s,", ipAddr->IpAddress.String);
left -= ret - ret_buf;
count++;
}
if (debug)
printf (" %s (secondary %d)\n", ipAddr->IpAddress.String, i+1);
}
quit:
if (handle)
FreeLibrary (handle);
if (debug && left <= ip_size)
printf ("Too many nameservers. Truncating to %d addressess", count);
if (ret > ret_buf)
ret[-1] = '\0';
return (count);
}
#endif
static int init_by_resolv_conf(ares_channel channel)
{
char *line = NULL;
int status = -1, nservers = 0, nsort = 0;
struct server_state *servers = NULL;
struct apattern *sortlist = NULL;
#ifdef WIN32
/*
NameServer info via IPHLPAPI (IP helper API):
GetNetworkParams() should be the trusted source for this.
Available in Win-98/2000 and later. If that fail, fall-back to
registry information.
NameServer Registry:
On Windows 9X, the DNS server can be found in:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP\NameServer
On Windows NT/2000/XP/2003:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\NameServer
or
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\DhcpNameServer
or
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\{AdapterID}\
NameServer
or
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\{AdapterID}\
DhcpNameServer
*/
HKEY mykey;
HKEY subkey;
DWORD data_type;
DWORD bytes;
DWORD result;
char buf[256];
if (channel->nservers > -1) /* don't override ARES_OPT_SERVER */
return ARES_SUCCESS;
if (get_iphlpapi_dns_info(buf,sizeof(buf)) > 0)
{
status = config_nameserver(&servers, &nservers, buf);
if (status == ARES_SUCCESS)
goto okay;
}
if (IS_NT())
{
if (RegOpenKeyEx(
HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0,
KEY_READ, &mykey
) == ERROR_SUCCESS)
{
RegOpenKeyEx(mykey, "Interfaces", 0,
KEY_QUERY_VALUE|KEY_ENUMERATE_SUB_KEYS, &subkey);
if (get_res_nt(mykey, NAMESERVER, &line))
{
status = config_nameserver(&servers, &nservers, line);
free(line);
}
else if (get_res_nt(mykey, DHCPNAMESERVER, &line))
{
status = config_nameserver(&servers, &nservers, line);
free(line);
}
/* Try the interfaces */
else if (get_res_interfaces_nt(subkey, NAMESERVER, &line))
{
status = config_nameserver(&servers, &nservers, line);
free(line);
}
else if (get_res_interfaces_nt(subkey, DHCPNAMESERVER, &line))
{
status = config_nameserver(&servers, &nservers, line);
free(line);
}
RegCloseKey(subkey);
RegCloseKey(mykey);
}
}
else
{
if (RegOpenKeyEx(
HKEY_LOCAL_MACHINE, WIN_NS_9X, 0,
KEY_READ, &mykey
) == ERROR_SUCCESS)
{
if ((result = RegQueryValueEx(
mykey, NAMESERVER, NULL, &data_type,
NULL, &bytes
)
) == ERROR_SUCCESS ||
result == ERROR_MORE_DATA)
{
if (bytes)
{
line = malloc(bytes+1);
if (RegQueryValueEx(mykey, NAMESERVER, NULL, &data_type,
(unsigned char *)line, &bytes) ==
ERROR_SUCCESS)
{
status = config_nameserver(&servers, &nservers, line);
}
free(line);
}
}
}
RegCloseKey(mykey);
}
if (status == ARES_SUCCESS)
status = ARES_EOF;
else
/* Catch the case when all the above checks fail (which happens when there
is no network card or the cable is unplugged) */
status = ARES_EFILE;
#elif defined(__riscos__)
/* Under RISC OS, name servers are listed in the
system variable Inet$Resolvers, space separated. */
line = getenv("Inet$Resolvers");
status = ARES_EOF;
if (line) {
char *resolvers = strdup(line), *pos, *space;
if (!resolvers)
return ARES_ENOMEM;
pos = resolvers;
do {
space = strchr(pos, ' ');
if (space)
*space = '\0';
status = config_nameserver(&servers, &nservers, pos);
if (status != ARES_SUCCESS)
break;
pos = space + 1;
} while (space);
if (status == ARES_SUCCESS)
status = ARES_EOF;
free(resolvers);
}
#elif defined(WATT32)
int i;
sock_init();
for (i = 0; def_nameservers[i]; i++)
;
if (i == 0)
return ARES_SUCCESS; /* use localhost DNS server */
nservers = i;
servers = calloc(sizeof(*servers), i);
if (!servers)
return ARES_ENOMEM;
for (i = 0; def_nameservers[i]; i++)
servers[i].addr.s_addr = htonl(def_nameservers[i]);
status = ARES_EOF;
#else
{
char *p;
FILE *fp;
int linesize;
int error;
/* Don't read resolv.conf and friends if we don't have to */
if (ARES_CONFIG_CHECK(channel))
return ARES_SUCCESS;
fp = fopen(PATH_RESOLV_CONF, "r");
if (fp) {
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
if ((p = try_config(line, "domain")) && channel->ndomains == -1)
status = config_domain(channel, p);
else if ((p = try_config(line, "lookup")) && !channel->lookups)
status = config_lookup(channel, p, "bind", "file");
else if ((p = try_config(line, "search")) && channel->ndomains == -1)
status = set_search(channel, p);
else if ((p = try_config(line, "nameserver")) && channel->nservers == -1)
status = config_nameserver(&servers, &nservers, p);
else if ((p = try_config(line, "sortlist")) && channel->nsort == -1)
status = config_sortlist(&sortlist, &nsort, p);
else if ((p = try_config(line, "options")))
status = set_options(channel, p);
else
status = ARES_SUCCESS;
if (status != ARES_SUCCESS)
break;
}
fclose(fp);
}
else {
error = ERRNO;
switch(error) {
case ENOENT:
case ESRCH:
status = ARES_EOF;
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n", PATH_RESOLV_CONF));
status = ARES_EFILE;
}
}
if ((status == ARES_EOF) && (!channel->lookups)) {
/* Many systems (Solaris, Linux, BSD's) use nsswitch.conf */
fp = fopen("/etc/nsswitch.conf", "r");
if (fp) {
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
if ((p = try_config(line, "hosts:")) && !channel->lookups)
status = config_lookup(channel, p, "dns", "files");
}
fclose(fp);
}
else {
error = ERRNO;
switch(error) {
case ENOENT:
case ESRCH:
status = ARES_EOF;
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n", "/etc/nsswitch.conf"));
status = ARES_EFILE;
}
}
}
if ((status == ARES_EOF) && (!channel->lookups)) {
/* Linux / GNU libc 2.x and possibly others have host.conf */
fp = fopen("/etc/host.conf", "r");
if (fp) {
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
if ((p = try_config(line, "order")) && !channel->lookups)
status = config_lookup(channel, p, "bind", "hosts");
}
fclose(fp);
}
else {
error = ERRNO;
switch(error) {
case ENOENT:
case ESRCH:
status = ARES_EOF;
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n", "/etc/host.conf"));
status = ARES_EFILE;
}
}
}
if ((status == ARES_EOF) && (!channel->lookups)) {
/* Tru64 uses /etc/svc.conf */
fp = fopen("/etc/svc.conf", "r");
if (fp) {
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
if ((p = try_config(line, "hosts=")) && !channel->lookups)
status = config_lookup(channel, p, "bind", "local");
}
fclose(fp);
}
else {
error = ERRNO;
switch(error) {
case ENOENT:
case ESRCH:
status = ARES_EOF;
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n", "/etc/svc.conf"));
status = ARES_EFILE;
}
}
}
if(line)
free(line);
}
#endif
/* Handle errors. */
if (status != ARES_EOF)
{
if (servers != NULL)
free(servers);
if (sortlist != NULL)
free(sortlist);
return status;
}
/* If we got any name server entries, fill them in. */
#ifdef WIN32
okay:
#endif
if (servers)
{
channel->servers = servers;
channel->nservers = nservers;
}
/* If we got any sortlist entries, fill them in. */
if (sortlist)
{
channel->sortlist = sortlist;
channel->nsort = nsort;
}
return ARES_SUCCESS;
}
static int init_by_defaults(ares_channel channel)
{
char *hostname = NULL;
int rc = ARES_SUCCESS;
if (channel->flags == -1)
channel->flags = 0;
if (channel->timeout == -1)
channel->timeout = DEFAULT_TIMEOUT;
if (channel->tries == -1)
channel->tries = DEFAULT_TRIES;
if (channel->ndots == -1)
channel->ndots = 1;
if (channel->rotate == -1)
channel->rotate = 0;
if (channel->udp_port == -1)
channel->udp_port = htons(NAMESERVER_PORT);
if (channel->tcp_port == -1)
channel->tcp_port = htons(NAMESERVER_PORT);
if (channel->nservers == -1) {
/* If nobody specified servers, try a local named. */
channel->servers = malloc(sizeof(struct server_state));
if (!channel->servers) {
rc = ARES_ENOMEM;
goto error;
}
channel->servers[0].addr.s_addr = htonl(INADDR_LOOPBACK);
channel->nservers = 1;
}
#ifdef ENAMETOOLONG
#define toolong(x) (x == -1) && ((ENAMETOOLONG == errno) || (EINVAL == errno))
#else
#define toolong(x) (x == -1) && (EINVAL == errno)
#endif
if (channel->ndomains == -1) {
/* Derive a default domain search list from the kernel hostname,
* or set it to empty if the hostname isn't helpful.
*/
size_t len = 64;
int res;
hostname = malloc(len);
if(!hostname) {
rc = ARES_ENOMEM;
goto error;
}
do {
res = gethostname(hostname, len);
if(toolong(res)) {
char *p;
len *= 2;
p = realloc(hostname, len);
if(!p) {
rc = ARES_ENOMEM;
goto error;
}
hostname = p;
continue;
}
else if(res) {
rc = ARES_EBADNAME;
goto error;
}
} while(0);
channel->ndomains = 0; /* default to none */
if (strchr(hostname, '.')) {
/* a dot was found */
channel->domains = malloc(sizeof(char *));
if (!channel->domains) {
rc = ARES_ENOMEM;
goto error;
}
channel->domains[0] = strdup(strchr(hostname, '.') + 1);
if (!channel->domains[0]) {
rc = ARES_ENOMEM;
goto error;
}
channel->ndomains = 1;
}
}
if (channel->nsort == -1) {
channel->sortlist = NULL;
channel->nsort = 0;
}
if (!channel->lookups) {
channel->lookups = strdup("fb");
if (!channel->lookups)
rc = ARES_ENOMEM;
}
error:
if(rc) {
if(channel->servers)
free(channel->servers);
if(channel->domains && channel->domains[0])
free(channel->domains[0]);
if(channel->domains)
free(channel->domains);
if(channel->lookups)
free(channel->lookups);
}
if(hostname)
free(hostname);
return rc;
}
#ifndef WIN32
static int config_domain(ares_channel channel, char *str)
{
char *q;
/* Set a single search domain. */
q = str;
while (*q && !ISSPACE(*q))
q++;
*q = '\0';
return set_search(channel, str);
}
static int config_lookup(ares_channel channel, const char *str,
const char *bindch, const char *filech)
{
char lookups[3], *l;
const char *p;
/* Set the lookup order. Only the first letter of each work
* is relevant, and it has to be "b" for DNS or "f" for the
* host file. Ignore everything else.
*/
l = lookups;
p = str;
while (*p)
{
if ((*p == *bindch || *p == *filech) && l < lookups + 2) {
if (*p == *bindch) *l++ = 'b';
else *l++ = 'f';
}
while (*p && !ISSPACE(*p) && (*p != ','))
p++;
while (*p && (ISSPACE(*p) || (*p == ',')))
p++;
}
*l = '\0';
channel->lookups = strdup(lookups);
return (channel->lookups) ? ARES_SUCCESS : ARES_ENOMEM;
}
#endif
static int config_nameserver(struct server_state **servers, int *nservers,
char *str)
{
struct in_addr addr;
struct server_state *newserv;
/* On Windows, there may be more than one nameserver specified in the same
* registry key, so we parse it as a space or comma seperated list.
*/
#ifdef WIN32
char *p = str;
char *begin = str;
int more = 1;
while (more)
{
more = 0;
while (*p && !ISSPACE(*p) && *p != ',')
p++;
if (*p)
{
*p = '\0';
more = 1;
}
/* Skip multiple spaces or trailing spaces */
if (!*begin)
{
begin = ++p;
continue;
}
/* This is the part that actually sets the nameserver */
addr.s_addr = inet_addr(begin);
if (addr.s_addr == INADDR_NONE)
continue;
newserv = realloc(*servers, (*nservers + 1) * sizeof(struct server_state));
if (!newserv)
return ARES_ENOMEM;
newserv[*nservers].addr = addr;
*servers = newserv;
(*nservers)++;
if (!more)
break;
begin = ++p;
}
#else
/* Add a nameserver entry, if this is a valid address. */
addr.s_addr = inet_addr(str);
if (addr.s_addr == INADDR_NONE)
return ARES_SUCCESS;
newserv = realloc(*servers, (*nservers + 1) * sizeof(struct server_state));
if (!newserv)
return ARES_ENOMEM;
newserv[*nservers].addr = addr;
*servers = newserv;
(*nservers)++;
#endif
return ARES_SUCCESS;
}
#ifndef WIN32
static int config_sortlist(struct apattern **sortlist, int *nsort,
const char *str)
{
struct apattern pat;
const char *q;
/* Add sortlist entries. */
while (*str && *str != ';')
{
int bits;
char ipbuf[16], ipbufpfx[32];
/* Find just the IP */
q = str;
while (*q && *q != '/' && *q != ';' && !ISSPACE(*q))
q++;
memcpy(ipbuf, str, (int)(q-str));
ipbuf[(int)(q-str)] = '\0';
/* Find the prefix */
if (*q == '/')
{
const char *str2 = q+1;
while (*q && *q != ';' && !ISSPACE(*q))
q++;
memcpy(ipbufpfx, str, (int)(q-str));
ipbufpfx[(int)(q-str)] = '\0';
str = str2;
}
else
ipbufpfx[0] = '\0';
/* Lets see if it is CIDR */
/* First we'll try IPv6 */
if ((bits = ares_inet_net_pton(AF_INET6, ipbufpfx[0] ? ipbufpfx : ipbuf,
&pat.addr.addr6,
sizeof(pat.addr.addr6))) > 0)
{
pat.type = PATTERN_CIDR;
pat.mask.bits = (unsigned short)bits;
pat.family = AF_INET6;
if (!sortlist_alloc(sortlist, nsort, &pat))
return ARES_ENOMEM;
}
if (ipbufpfx[0] &&
(bits = ares_inet_net_pton(AF_INET, ipbufpfx, &pat.addr.addr4,
sizeof(pat.addr.addr4))) > 0)
{
pat.type = PATTERN_CIDR;
pat.mask.bits = (unsigned short)bits;
pat.family = AF_INET;
if (!sortlist_alloc(sortlist, nsort, &pat))
return ARES_ENOMEM;
}
/* See if it is just a regular IP */
else if (ip_addr(ipbuf, (int)(q-str), &pat.addr.addr4) == 0)
{
if (ipbufpfx[0])
{
memcpy(ipbuf, str, (int)(q-str));
ipbuf[(int)(q-str)] = '\0';
if (ip_addr(ipbuf, (int)(q - str), &pat.mask.addr.addr4) != 0)
natural_mask(&pat);
}
else
natural_mask(&pat);
pat.family = AF_INET;
pat.type = PATTERN_MASK;
if (!sortlist_alloc(sortlist, nsort, &pat))
return ARES_ENOMEM;
}
else
{
while (*q && *q != ';' && !ISSPACE(*q))
q++;
}
str = q;
while (ISSPACE(*str))
str++;
}
return ARES_SUCCESS;
}
#endif
static int set_search(ares_channel channel, const char *str)
{
int n;
const char *p, *q;
if(channel->ndomains != -1) {
/* if we already have some domains present, free them first */
for(n=0; n < channel->ndomains; n++)
free(channel->domains[n]);
free(channel->domains);
channel->domains = NULL;
channel->ndomains = -1;
}
/* Count the domains given. */
n = 0;
p = str;
while (*p)
{
while (*p && !ISSPACE(*p))
p++;
while (ISSPACE(*p))
p++;
n++;
}
if (!n)
{
channel->ndomains = 0;
return ARES_SUCCESS;
}
channel->domains = malloc(n * sizeof(char *));
if (!channel->domains)
return ARES_ENOMEM;
/* Now copy the domains. */
n = 0;
p = str;
while (*p)
{
channel->ndomains = n;
q = p;
while (*q && !ISSPACE(*q))
q++;
channel->domains[n] = malloc(q - p + 1);
if (!channel->domains[n])
return ARES_ENOMEM;
memcpy(channel->domains[n], p, q - p);
channel->domains[n][q - p] = 0;
p = q;
while (ISSPACE(*p))
p++;
n++;
}
channel->ndomains = n;
return ARES_SUCCESS;
}
static int set_options(ares_channel channel, const char *str)
{
const char *p, *q, *val;
p = str;
while (*p)
{
q = p;
while (*q && !ISSPACE(*q))
q++;
val = try_option(p, q, "ndots:");
if (val && channel->ndots == -1)
channel->ndots = atoi(val);
val = try_option(p, q, "retrans:");
if (val && channel->timeout == -1)
channel->timeout = atoi(val);
val = try_option(p, q, "retry:");
if (val && channel->tries == -1)
channel->tries = atoi(val);
val = try_option(p, q, "rotate");
if (val && channel->rotate == -1)
channel->rotate = 1;
p = q;
while (ISSPACE(*p))
p++;
}
return ARES_SUCCESS;
}
#ifndef WIN32
static char *try_config(char *s, const char *opt)
{
size_t len;
ssize_t i;
ssize_t j;
char *p;
if (!s || !opt)
/* no line or no option */
return NULL;
/* trim line comment */
for (i = 0; s[i] && s[i] != '#'; ++i);
s[i] = '\0';
/* trim trailing whitespace */
for (j = i-1; j >= 0 && ISSPACE(s[j]); --j);
s[++j] = '\0';
/* skip leading whitespace */
for (i = 0; s[i] && ISSPACE(s[i]); ++i);
p = &s[i];
if (!*p)
/* empty line */
return NULL;
if ((len = strlen(opt)) == 0)
/* empty option */
return NULL;
if (strncmp(p, opt, len) != 0)
/* line and option do not match */
return NULL;
/* skip over given option name */
p += len;
if (!*p)
/* no option value */
return NULL;
if ((opt[len-1] != ':') && (opt[len-1] != '=') && !ISSPACE(*p))
/* whitespace between option name and value is mandatory
for given option names which do not end with ':' or '=' */
return NULL;
/* skip over whitespace */
while (*p && ISSPACE(*p))
p++;
if (!*p)
/* no option value */
return NULL;
/* return pointer to option value */
return p;
}
#endif
static const char *try_option(const char *p, const char *q, const char *opt)
{
size_t len = strlen(opt);
return ((size_t)(q - p) >= len && !strncmp(p, opt, len)) ? &p[len] : NULL;
}
#ifndef WIN32
static int sortlist_alloc(struct apattern **sortlist, int *nsort,
struct apattern *pat)
{
struct apattern *newsort;
newsort = realloc(*sortlist, (*nsort + 1) * sizeof(struct apattern));
if (!newsort)
return 0;
newsort[*nsort] = *pat;
*sortlist = newsort;
(*nsort)++;
return 1;
}
static int ip_addr(const char *ipbuf, int len, struct in_addr *addr)
{
/* Four octets and three periods yields at most 15 characters. */
if (len > 15)
return -1;
addr->s_addr = inet_addr(ipbuf);
if (addr->s_addr == INADDR_NONE && strcmp(ipbuf, "255.255.255.255") != 0)
return -1;
return 0;
}
static void natural_mask(struct apattern *pat)
{
struct in_addr addr;
/* Store a host-byte-order copy of pat in a struct in_addr. Icky,
* but portable.
*/
addr.s_addr = ntohl(pat->addr.addr4.s_addr);
/* This is out of date in the CIDR world, but some people might
* still rely on it.
*/
if (IN_CLASSA(addr.s_addr))
pat->mask.addr.addr4.s_addr = htonl(IN_CLASSA_NET);
else if (IN_CLASSB(addr.s_addr))
pat->mask.addr.addr4.s_addr = htonl(IN_CLASSB_NET);
else
pat->mask.addr.addr4.s_addr = htonl(IN_CLASSC_NET);
}
#endif
/* initialize an rc4 key. If possible a cryptographically secure random key
is generated using a suitable function (for example win32's RtlGenRandom as
described in
http://blogs.msdn.com/michael_howard/archive/2005/01/14/353379.aspx
otherwise the code defaults to cross-platform albeit less secure mechanism
using rand
*/
static void randomize_key(unsigned char* key,int key_data_len)
{
int randomized = 0;
int counter=0;
#ifdef WIN32
HMODULE lib=LoadLibrary("ADVAPI32.DLL");
if (lib) {
BOOLEAN (APIENTRY *pfn)(void*, ULONG) =
(BOOLEAN (APIENTRY *)(void*,ULONG))GetProcAddress(lib,"SystemFunction036");
if (pfn && pfn(key,key_data_len) )
randomized = 1;
FreeLibrary(lib);
}
#else /* !WIN32 */
#ifdef RANDOM_FILE
FILE *f = fopen(RANDOM_FILE, "rb");
if(f) {
counter = fread(key, 1, key_data_len, f);
fclose(f);
}
#endif
#endif /* WIN32 */
if ( !randomized ) {
for (;counter<key_data_len;counter++)
key[counter]=(unsigned char)(rand() % 256);
}
}
static int init_id_key(rc4_key* key,int key_data_len)
{
unsigned char index1;
unsigned char index2;
unsigned char* state;
short counter;
unsigned char *key_data_ptr = 0;
key_data_ptr = calloc(1,key_data_len);
if (!key_data_ptr)
return ARES_ENOMEM;
state = &key->state[0];
for(counter = 0; counter < 256; counter++)
/* unnecessary AND but it keeps some compilers happier */
state[counter] = (unsigned char)(counter & 0xff);
randomize_key(key->state,key_data_len);
key->x = 0;
key->y = 0;
index1 = 0;
index2 = 0;
for(counter = 0; counter < 256; counter++)
{
index2 = (unsigned char)((key_data_ptr[index1] + state[counter] +
index2) % 256);
ARES_SWAP_BYTE(&state[counter], &state[index2]);
index1 = (unsigned char)((index1 + 1) % key_data_len);
}
free(key_data_ptr);
return ARES_SUCCESS;
}
short ares__generate_new_id(rc4_key* key)
{
short r=0;
ares__rc4(key, (unsigned char *)&r, sizeof(r));
return r;
}