From 19fcec84d8d7d21e796c7624e521b60d28ee21ed Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:45:59 +0200 Subject: Adding upstream version 16.2.11+ds. Signed-off-by: Daniel Baumann --- src/c-ares/ares_gethostbyname.c | 518 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 518 insertions(+) create mode 100644 src/c-ares/ares_gethostbyname.c (limited to 'src/c-ares/ares_gethostbyname.c') diff --git a/src/c-ares/ares_gethostbyname.c b/src/c-ares/ares_gethostbyname.c new file mode 100644 index 000000000..caab6ae49 --- /dev/null +++ b/src/c-ares/ares_gethostbyname.c @@ -0,0 +1,518 @@ + +/* 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 +#endif +#ifdef HAVE_NETDB_H +# include +#endif +#ifdef HAVE_ARPA_INET_H +# include +#endif +#ifdef HAVE_ARPA_NAMESER_H +# include +#else +# include "nameser.h" +#endif +#ifdef HAVE_ARPA_NAMESER_COMPAT_H +# include +#endif + +#ifdef HAVE_STRINGS_H +#include +#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; + } + + 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; + +#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; +} -- cgit v1.2.3