| |
| /* Copyright 1998 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_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 |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <ctype.h> |
| #ifdef HAVE_STRINGS_H |
| #include <strings.h> |
| #endif |
| |
| #include "ares.h" |
| #include "inet_net_pton.h" |
| #include "bitncmp.h" |
| #include "ares_platform.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; |
| } |
| |
| if (fake_hostent(name, family, callback, arg)) |
| return; |
| |
| /* Allocate and fill in the host query structure. */ |
| hquery = malloc(sizeof(struct host_query)); |
| if (!hquery) |
| { |
| callback(arg, ARES_ENOMEM, 0, NULL); |
| return; |
| } |
| hquery->channel = channel; |
| hquery->name = strdup(name); |
| hquery->want_family = family; |
| hquery->sent_family = -1; /* nothing is sent yet */ |
| if (!hquery->name) { |
| 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) && |
| 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. */ |
| 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); |
| free(hquery->name); |
| 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 = 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 = family; |
| hostent.h_addr_list = addrs; |
| callback(arg, ARES_SUCCESS, 0, &hostent); |
| |
| 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; |
| |
| #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 (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ, |
| &hkeyHosts) == ERROR_SUCCESS) |
| { |
| DWORD dwLength = MAX_PATH; |
| RegQueryValueEx(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp, |
| &dwLength); |
| ExpandEnvironmentStrings(tmp, PATH_HOSTS, MAX_PATH); |
| RegCloseKey(hkeyHosts); |
| } |
| } |
| else if (platform == WIN_9X) |
| GetWindowsDirectory(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; |
| } |
