--- /dev/null
+
+/* Copyright 1998, 2011, 2013 by the Massachusetts Institute of Technology.
+ *
+ * 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_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_STRINGS_H
+#include <strings.h>
+#endif
+
+#include "ares.h"
+#include "ares_inet_net_pton.h"
+#include "bitncmp.h"
+#include "ares_platform.h"
+#include "ares_nowarn.h"
+#include "ares_private.h"
+
+#ifdef WATT32
+#undef WIN32
+#endif
+
+struct host_query {
+ /* Arguments passed to ares_gethostbyname() */
+ ares_channel channel;
+ char *name;
+ ares_host_callback callback;
+ void *arg;
+ int sent_family; /* this family is what was is being used */
+ int want_family; /* this family is what is asked for in the API */
+ const char *remaining_lookups;
+ int timeouts;
+};
+
+static void next_lookup(struct host_query *hquery, int status_code);
+static void host_callback(void *arg, int status, int timeouts,
+ unsigned char *abuf, int alen);
+static void end_hquery(struct host_query *hquery, int status,
+ struct hostent *host);
+static int fake_hostent(const char *name, int family,
+ ares_host_callback callback, void *arg);
+static int file_lookup(const char *name, int family, struct hostent **host);
+static void sort_addresses(struct hostent *host,
+ const struct apattern *sortlist, int nsort);
+static void sort6_addresses(struct hostent *host,
+ const struct apattern *sortlist, int nsort);
+static int get_address_index(const struct in_addr *addr,
+ const struct apattern *sortlist, int nsort);
+static int get6_address_index(const struct ares_in6_addr *addr,
+ const struct apattern *sortlist, int nsort);
+
+void ares_gethostbyname(ares_channel channel, const char *name, int family,
+ ares_host_callback callback, void *arg)
+{
+ struct host_query *hquery;
+
+ /* Right now we only know how to look up Internet addresses - and unspec
+ means try both basically. */
+ switch (family) {
+ case AF_INET:
+ case AF_INET6:
+ case AF_UNSPEC:
+ break;
+ default:
+ callback(arg, ARES_ENOTIMP, 0, NULL);
+ return;
+ }
+
+ /* Per RFC 7686, reject queries for ".onion" domain names with NXDOMAIN. */
+ if (ares__is_onion_domain(name))
+ {
+ callback(arg, ARES_ENOTFOUND, 0, NULL);
+ return;
+ }
+
+ if (fake_hostent(name, family, callback, arg))
+ return;
+
+ /* Allocate and fill in the host query structure. */
+ hquery = ares_malloc(sizeof(struct host_query));
+ if (!hquery)
+ {
+ callback(arg, ARES_ENOMEM, 0, NULL);
+ return;
+ }
+ hquery->channel = channel;
+ hquery->name = ares_strdup(name);
+ hquery->want_family = family;
+ hquery->sent_family = -1; /* nothing is sent yet */
+ if (!hquery->name) {
+ ares_free(hquery);
+ callback(arg, ARES_ENOMEM, 0, NULL);
+ return;
+ }
+ hquery->callback = callback;
+ hquery->arg = arg;
+ hquery->remaining_lookups = channel->lookups;
+ hquery->timeouts = 0;
+
+ /* Start performing lookups according to channel->lookups. */
+ next_lookup(hquery, ARES_ECONNREFUSED /* initial error code */);
+}
+
+static void next_lookup(struct host_query *hquery, int status_code)
+{
+ const char *p;
+ struct hostent *host;
+ int status = status_code;
+
+ for (p = hquery->remaining_lookups; *p; p++)
+ {
+ switch (*p)
+ {
+ case 'b':
+ /* DNS lookup */
+ hquery->remaining_lookups = p + 1;
+ if ((hquery->want_family == AF_INET6) ||
+ (hquery->want_family == AF_UNSPEC)) {
+ /* if inet6 or unspec, start out with AAAA */
+ hquery->sent_family = AF_INET6;
+ ares_search(hquery->channel, hquery->name, C_IN, T_AAAA,
+ host_callback, hquery);
+ }
+ else {
+ hquery->sent_family = AF_INET;
+ ares_search(hquery->channel, hquery->name, C_IN, T_A,
+ host_callback, hquery);
+ }
+ return;
+
+ case 'f':
+ /* Host file lookup */
+ status = file_lookup(hquery->name, hquery->want_family, &host);
+
+ /* this status check below previously checked for !ARES_ENOTFOUND,
+ but we should not assume that this single error code is the one
+ that can occur, as that is in fact no longer the case */
+ if (status == ARES_SUCCESS)
+ {
+ end_hquery(hquery, status, host);
+ return;
+ }
+ status = status_code; /* Use original status code */
+ break;
+ }
+ }
+ end_hquery(hquery, status, NULL);
+}
+
+static void host_callback(void *arg, int status, int timeouts,
+ unsigned char *abuf, int alen)
+{
+ struct host_query *hquery = (struct host_query *) arg;
+ ares_channel channel = hquery->channel;
+ struct hostent *host = NULL;
+
+ hquery->timeouts += timeouts;
+ if (status == ARES_SUCCESS)
+ {
+ if (hquery->sent_family == AF_INET)
+ {
+ status = ares_parse_a_reply(abuf, alen, &host, NULL, NULL);
+ if (host && channel->nsort)
+ sort_addresses(host, channel->sortlist, channel->nsort);
+ }
+ else if (hquery->sent_family == AF_INET6)
+ {
+ status = ares_parse_aaaa_reply(abuf, alen, &host, NULL, NULL);
+ if ((status == ARES_ENODATA || status == ARES_EBADRESP ||
+ (status == ARES_SUCCESS && host && host->h_addr_list[0] == NULL)) &&
+ hquery->want_family == AF_UNSPEC) {
+ /* The query returned something but either there were no AAAA
+ records (e.g. just CNAME) or the response was malformed. Try
+ looking up A instead. */
+ if (host)
+ ares_free_hostent(host);
+ hquery->sent_family = AF_INET;
+ ares_search(hquery->channel, hquery->name, C_IN, T_A,
+ host_callback, hquery);
+ return;
+ }
+ if (host && channel->nsort)
+ sort6_addresses(host, channel->sortlist, channel->nsort);
+ }
+ end_hquery(hquery, status, host);
+ }
+ else if ((status == ARES_ENODATA || status == ARES_EBADRESP ||
+ status == ARES_ETIMEOUT) && (hquery->sent_family == AF_INET6 &&
+ hquery->want_family == AF_UNSPEC))
+ {
+ /* The AAAA query yielded no useful result. Now look up an A instead. */
+ hquery->sent_family = AF_INET;
+ ares_search(hquery->channel, hquery->name, C_IN, T_A, host_callback,
+ hquery);
+ }
+ else if (status == ARES_EDESTRUCTION)
+ end_hquery(hquery, status, NULL);
+ else
+ next_lookup(hquery, status);
+}
+
+static void end_hquery(struct host_query *hquery, int status,
+ struct hostent *host)
+{
+ hquery->callback(hquery->arg, status, hquery->timeouts, host);
+ if (host)
+ ares_free_hostent(host);
+ ares_free(hquery->name);
+ ares_free(hquery);
+}
+
+/* If the name looks like an IP address, fake up a host entry, end the
+ * query immediately, and return true. Otherwise return false.
+ */
+static int fake_hostent(const char *name, int family,
+ ares_host_callback callback, void *arg)
+{
+ struct hostent hostent;
+ char *aliases[1] = { NULL };
+ char *addrs[2];
+ int result = 0;
+ struct in_addr in;
+ struct ares_in6_addr in6;
+
+ if (family == AF_INET || family == AF_INET6)
+ {
+ /* It only looks like an IP address if it's all numbers and dots. */
+ int numdots = 0, valid = 1;
+ const char *p;
+ for (p = name; *p; p++)
+ {
+ if (!ISDIGIT(*p) && *p != '.') {
+ valid = 0;
+ break;
+ } else if (*p == '.') {
+ numdots++;
+ }
+ }
+
+ /* if we don't have 3 dots, it is illegal
+ * (although inet_addr doesn't think so).
+ */
+ if (numdots != 3 || !valid)
+ result = 0;
+ else
+ result = ((in.s_addr = inet_addr(name)) == INADDR_NONE ? 0 : 1);
+
+ if (result)
+ family = AF_INET;
+ }
+ if (family == AF_INET6)
+ result = (ares_inet_pton(AF_INET6, name, &in6) < 1 ? 0 : 1);
+
+ if (!result)
+ return 0;
+
+ if (family == AF_INET)
+ {
+ hostent.h_length = (int)sizeof(struct in_addr);
+ addrs[0] = (char *)∈
+ }
+ else if (family == AF_INET6)
+ {
+ hostent.h_length = (int)sizeof(struct ares_in6_addr);
+ addrs[0] = (char *)&in6;
+ }
+ /* Duplicate the name, to avoid a constness violation. */
+ hostent.h_name = ares_strdup(name);
+ if (!hostent.h_name)
+ {
+ callback(arg, ARES_ENOMEM, 0, NULL);
+ return 1;
+ }
+
+ /* Fill in the rest of the host structure and terminate the query. */
+ addrs[1] = NULL;
+ hostent.h_aliases = aliases;
+ hostent.h_addrtype = aresx_sitoss(family);
+ hostent.h_addr_list = addrs;
+ callback(arg, ARES_SUCCESS, 0, &hostent);
+
+ ares_free((char *)(hostent.h_name));
+ return 1;
+}
+
+/* This is an API method */
+int ares_gethostbyname_file(ares_channel channel, const char *name,
+ int family, struct hostent **host)
+{
+ int result;
+
+ /* We only take the channel to ensure that ares_init() been called. */
+ if(channel == NULL)
+ {
+ /* Anything will do, really. This seems fine, and is consistent with
+ other error cases. */
+ *host = NULL;
+ return ARES_ENOTFOUND;
+ }
+
+ /* Just chain to the internal implementation we use here; it's exactly
+ * what we want.
+ */
+ result = file_lookup(name, family, host);
+ if(result != ARES_SUCCESS)
+ {
+ /* We guarantee a NULL hostent on failure. */
+ *host = NULL;
+ }
+ return result;
+}
+
+static int file_lookup(const char *name, int family, struct hostent **host)
+{
+ FILE *fp;
+ char **alias;
+ int status;
+ int error;
+
+ /* Per RFC 7686, reject queries for ".onion" domain names with NXDOMAIN. */
+ if (ares__is_onion_domain(name))
+ return ARES_ENOTFOUND;
+
+#ifdef WIN32
+ char PATH_HOSTS[MAX_PATH];
+ win_platform platform;
+
+ PATH_HOSTS[0] = '\0';
+
+ platform = ares__getplatform();
+
+ if (platform == WIN_NT) {
+ char tmp[MAX_PATH];
+ HKEY hkeyHosts;
+
+ if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ,
+ &hkeyHosts) == ERROR_SUCCESS)
+ {
+ DWORD dwLength = MAX_PATH;
+ RegQueryValueExA(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp,
+ &dwLength);
+ ExpandEnvironmentStringsA(tmp, PATH_HOSTS, MAX_PATH);
+ RegCloseKey(hkeyHosts);
+ }
+ }
+ else if (platform == WIN_9X)
+ GetWindowsDirectoryA(PATH_HOSTS, MAX_PATH);
+ else
+ return ARES_ENOTFOUND;
+
+ strcat(PATH_HOSTS, WIN_PATH_HOSTS);
+
+#elif defined(WATT32)
+ extern const char *_w32_GetHostsFile (void);
+ const char *PATH_HOSTS = _w32_GetHostsFile();
+
+ if (!PATH_HOSTS)
+ return ARES_ENOTFOUND;
+#endif
+
+ fp = fopen(PATH_HOSTS, "r");
+ if (!fp)
+ {
+ error = ERRNO;
+ switch(error)
+ {
+ case ENOENT:
+ case ESRCH:
+ return ARES_ENOTFOUND;
+ default:
+ DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
+ error, strerror(error)));
+ DEBUGF(fprintf(stderr, "Error opening file: %s\n",
+ PATH_HOSTS));
+ *host = NULL;
+ return ARES_EFILE;
+ }
+ }
+ while ((status = ares__get_hostent(fp, family, host)) == ARES_SUCCESS)
+ {
+ if (strcasecmp((*host)->h_name, name) == 0)
+ break;
+ for (alias = (*host)->h_aliases; *alias; alias++)
+ {
+ if (strcasecmp(*alias, name) == 0)
+ break;
+ }
+ if (*alias)
+ break;
+ ares_free_hostent(*host);
+ }
+ fclose(fp);
+ if (status == ARES_EOF)
+ status = ARES_ENOTFOUND;
+ if (status != ARES_SUCCESS)
+ *host = NULL;
+ return status;
+}
+
+static void sort_addresses(struct hostent *host,
+ const struct apattern *sortlist, int nsort)
+{
+ struct in_addr a1, a2;
+ int i1, i2, ind1, ind2;
+
+ /* This is a simple insertion sort, not optimized at all. i1 walks
+ * through the address list, with the loop invariant that everything
+ * to the left of i1 is sorted. In the loop body, the value at i1 is moved
+ * back through the list (via i2) until it is in sorted order.
+ */
+ for (i1 = 0; host->h_addr_list[i1]; i1++)
+ {
+ memcpy(&a1, host->h_addr_list[i1], sizeof(struct in_addr));
+ ind1 = get_address_index(&a1, sortlist, nsort);
+ for (i2 = i1 - 1; i2 >= 0; i2--)
+ {
+ memcpy(&a2, host->h_addr_list[i2], sizeof(struct in_addr));
+ ind2 = get_address_index(&a2, sortlist, nsort);
+ if (ind2 <= ind1)
+ break;
+ memcpy(host->h_addr_list[i2 + 1], &a2, sizeof(struct in_addr));
+ }
+ memcpy(host->h_addr_list[i2 + 1], &a1, sizeof(struct in_addr));
+ }
+}
+
+/* Find the first entry in sortlist which matches addr. Return nsort
+ * if none of them match.
+ */
+static int get_address_index(const struct in_addr *addr,
+ const struct apattern *sortlist,
+ int nsort)
+{
+ int i;
+
+ for (i = 0; i < nsort; i++)
+ {
+ if (sortlist[i].family != AF_INET)
+ continue;
+ if (sortlist[i].type == PATTERN_MASK)
+ {
+ if ((addr->s_addr & sortlist[i].mask.addr4.s_addr)
+ == sortlist[i].addrV4.s_addr)
+ break;
+ }
+ else
+ {
+ if (!ares__bitncmp(&addr->s_addr, &sortlist[i].addrV4.s_addr,
+ sortlist[i].mask.bits))
+ break;
+ }
+ }
+ return i;
+}
+
+static void sort6_addresses(struct hostent *host,
+ const struct apattern *sortlist, int nsort)
+{
+ struct ares_in6_addr a1, a2;
+ int i1, i2, ind1, ind2;
+
+ /* This is a simple insertion sort, not optimized at all. i1 walks
+ * through the address list, with the loop invariant that everything
+ * to the left of i1 is sorted. In the loop body, the value at i1 is moved
+ * back through the list (via i2) until it is in sorted order.
+ */
+ for (i1 = 0; host->h_addr_list[i1]; i1++)
+ {
+ memcpy(&a1, host->h_addr_list[i1], sizeof(struct ares_in6_addr));
+ ind1 = get6_address_index(&a1, sortlist, nsort);
+ for (i2 = i1 - 1; i2 >= 0; i2--)
+ {
+ memcpy(&a2, host->h_addr_list[i2], sizeof(struct ares_in6_addr));
+ ind2 = get6_address_index(&a2, sortlist, nsort);
+ if (ind2 <= ind1)
+ break;
+ memcpy(host->h_addr_list[i2 + 1], &a2, sizeof(struct ares_in6_addr));
+ }
+ memcpy(host->h_addr_list[i2 + 1], &a1, sizeof(struct ares_in6_addr));
+ }
+}
+
+/* Find the first entry in sortlist which matches addr. Return nsort
+ * if none of them match.
+ */
+static int get6_address_index(const struct ares_in6_addr *addr,
+ const struct apattern *sortlist,
+ int nsort)
+{
+ int i;
+
+ for (i = 0; i < nsort; i++)
+ {
+ if (sortlist[i].family != AF_INET6)
+ continue;
+ if (!ares__bitncmp(addr, &sortlist[i].addrV6, sortlist[i].mask.bits))
+ break;
+ }
+ return i;
+}
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