diff options
Diffstat (limited to 'src/c-ares/ares_gethostbyaddr.c')
| -rw-r--r-- | src/c-ares/ares_gethostbyaddr.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/src/c-ares/ares_gethostbyaddr.c b/src/c-ares/ares_gethostbyaddr.c new file mode 100644 index 000000000..9258919a3 --- /dev/null +++ b/src/c-ares/ares_gethostbyaddr.c @@ -0,0 +1,294 @@ + +/* 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_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 "ares.h" +#include "ares_inet_net_pton.h" +#include "ares_platform.h" +#include "ares_private.h" + +#ifdef WATT32 +#undef WIN32 +#endif + +struct addr_query { + /* Arguments passed to ares_gethostbyaddr() */ + ares_channel channel; + struct ares_addr addr; + ares_host_callback callback; + void *arg; + + const char *remaining_lookups; + int timeouts; +}; + +static void next_lookup(struct addr_query *aquery); +static void addr_callback(void *arg, int status, int timeouts, + unsigned char *abuf, int alen); +static void end_aquery(struct addr_query *aquery, int status, + struct hostent *host); +static int file_lookup(struct ares_addr *addr, struct hostent **host); +static void ptr_rr_name(char *name, const struct ares_addr *addr); + +void ares_gethostbyaddr(ares_channel channel, const void *addr, int addrlen, + int family, ares_host_callback callback, void *arg) +{ + struct addr_query *aquery; + + if (family != AF_INET && family != AF_INET6) + { + callback(arg, ARES_ENOTIMP, 0, NULL); + return; + } + + if ((family == AF_INET && addrlen != sizeof(aquery->addr.addrV4)) || + (family == AF_INET6 && addrlen != sizeof(aquery->addr.addrV6))) + { + callback(arg, ARES_ENOTIMP, 0, NULL); + return; + } + + aquery = ares_malloc(sizeof(struct addr_query)); + if (!aquery) + { + callback(arg, ARES_ENOMEM, 0, NULL); + return; + } + aquery->channel = channel; + if (family == AF_INET) + memcpy(&aquery->addr.addrV4, addr, sizeof(aquery->addr.addrV4)); + else + memcpy(&aquery->addr.addrV6, addr, sizeof(aquery->addr.addrV6)); + aquery->addr.family = family; + aquery->callback = callback; + aquery->arg = arg; + aquery->remaining_lookups = channel->lookups; + aquery->timeouts = 0; + + next_lookup(aquery); +} + +static void next_lookup(struct addr_query *aquery) +{ + const char *p; + char name[128]; + int status; + struct hostent *host; + + for (p = aquery->remaining_lookups; *p; p++) + { + switch (*p) + { + case 'b': + ptr_rr_name(name, &aquery->addr); + aquery->remaining_lookups = p + 1; + ares_query(aquery->channel, name, C_IN, T_PTR, addr_callback, + aquery); + return; + case 'f': + status = file_lookup(&aquery->addr, &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_aquery(aquery, status, host); + return; + } + break; + } + } + end_aquery(aquery, ARES_ENOTFOUND, NULL); +} + +static void addr_callback(void *arg, int status, int timeouts, + unsigned char *abuf, int alen) +{ + struct addr_query *aquery = (struct addr_query *) arg; + struct hostent *host; + size_t addrlen; + + aquery->timeouts += timeouts; + if (status == ARES_SUCCESS) + { + if (aquery->addr.family == AF_INET) + { + addrlen = sizeof(aquery->addr.addrV4); + status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addrV4, + (int)addrlen, AF_INET, &host); + } + else + { + addrlen = sizeof(aquery->addr.addrV6); + status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addrV6, + (int)addrlen, AF_INET6, &host); + } + end_aquery(aquery, status, host); + } + else if (status == ARES_EDESTRUCTION) + end_aquery(aquery, status, NULL); + else + next_lookup(aquery); +} + +static void end_aquery(struct addr_query *aquery, int status, + struct hostent *host) +{ + aquery->callback(aquery->arg, status, aquery->timeouts, host); + if (host) + ares_free_hostent(host); + ares_free(aquery); +} + +static int file_lookup(struct ares_addr *addr, struct hostent **host) +{ + FILE *fp; + 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, addr->family, host)) == ARES_SUCCESS) + { + if (addr->family != (*host)->h_addrtype) + { + ares_free_hostent(*host); + continue; + } + if (addr->family == AF_INET) + { + if (memcmp((*host)->h_addr, &addr->addrV4, + sizeof(addr->addrV4)) == 0) + break; + } + else if (addr->family == AF_INET6) + { + if (memcmp((*host)->h_addr, &addr->addrV6, + sizeof(addr->addrV6)) == 0) + break; + } + ares_free_hostent(*host); + } + fclose(fp); + if (status == ARES_EOF) + status = ARES_ENOTFOUND; + if (status != ARES_SUCCESS) + *host = NULL; + return status; +} + +static void ptr_rr_name(char *name, const struct ares_addr *addr) +{ + if (addr->family == AF_INET) + { + unsigned long laddr = ntohl(addr->addrV4.s_addr); + unsigned long a1 = (laddr >> 24UL) & 0xFFUL; + unsigned long a2 = (laddr >> 16UL) & 0xFFUL; + unsigned long a3 = (laddr >> 8UL) & 0xFFUL; + unsigned long a4 = laddr & 0xFFUL; + sprintf(name, "%lu.%lu.%lu.%lu.in-addr.arpa", a4, a3, a2, a1); + } + else + { + unsigned char *bytes = (unsigned char *)&addr->addrV6; + /* There are too many arguments to do this in one line using + * minimally C89-compliant compilers */ + sprintf(name, + "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.", + bytes[15]&0xf, bytes[15] >> 4, bytes[14]&0xf, bytes[14] >> 4, + bytes[13]&0xf, bytes[13] >> 4, bytes[12]&0xf, bytes[12] >> 4, + bytes[11]&0xf, bytes[11] >> 4, bytes[10]&0xf, bytes[10] >> 4, + bytes[9]&0xf, bytes[9] >> 4, bytes[8]&0xf, bytes[8] >> 4); + sprintf(name+strlen(name), + "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa", + bytes[7]&0xf, bytes[7] >> 4, bytes[6]&0xf, bytes[6] >> 4, + bytes[5]&0xf, bytes[5] >> 4, bytes[4]&0xf, bytes[4] >> 4, + bytes[3]&0xf, bytes[3] >> 4, bytes[2]&0xf, bytes[2] >> 4, + bytes[1]&0xf, bytes[1] >> 4, bytes[0]&0xf, bytes[0] >> 4); + } +} |