diff options
Diffstat (limited to 'ares_gethostbyaddr.c')
| -rw-r--r-- | ares_gethostbyaddr.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/ares_gethostbyaddr.c b/ares_gethostbyaddr.c new file mode 100644 index 0000000..7353f09 --- /dev/null +++ b/ares_gethostbyaddr.c @@ -0,0 +1,174 @@ +/* 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. + */ + +static const char rcsid[] = "$Id$"; + +#include <sys/types.h> + +#ifdef WIN32 +#include "nameser.h" +#else +#include <sys/socket.h> +#include <netinet/in.h> +#include <netdb.h> +#include <arpa/nameser.h> +#endif + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include "ares.h" +#include "ares_private.h" + +struct addr_query { + /* Arguments passed to ares_gethostbyaddr() */ + ares_channel channel; + struct in_addr addr; + ares_host_callback callback; + void *arg; + + const char *remaining_lookups; +}; + +static void next_lookup(struct addr_query *aquery); +static void addr_callback(void *arg, int status, unsigned char *abuf, + int alen); +static void end_aquery(struct addr_query *aquery, int status, + struct hostent *host); +static int file_lookup(struct in_addr *addr, struct hostent **host); + +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 || addrlen != sizeof(struct in_addr)) + { + callback(arg, ARES_ENOTIMP, NULL); + return; + } + + aquery = malloc(sizeof(struct addr_query)); + if (!aquery) + { + callback(arg, ARES_ENOMEM, NULL); + return; + } + aquery->channel = channel; + memcpy(&aquery->addr, addr, sizeof(aquery->addr)); + aquery->callback = callback; + aquery->arg = arg; + aquery->remaining_lookups = channel->lookups; + + next_lookup(aquery); +} + +static void next_lookup(struct addr_query *aquery) +{ + const char *p; + char name[64]; + int a1, a2, a3, a4, status; + struct hostent *host; + unsigned long addr; + + for (p = aquery->remaining_lookups; *p; p++) + { + switch (*p) + { + case 'b': + addr = ntohl(aquery->addr.s_addr); + a1 = addr >> 24; + a2 = (addr >> 16) & 0xff; + a3 = (addr >> 8) & 0xff; + a4 = addr & 0xff; + sprintf(name, "%d.%d.%d.%d.in-addr.arpa", a4, a3, a2, a1); + 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); + if (status != ARES_ENOTFOUND) + { + end_aquery(aquery, status, host); + return; + } + break; + } + } + end_aquery(aquery, ARES_ENOTFOUND, NULL); +} + +static void addr_callback(void *arg, int status, unsigned char *abuf, int alen) +{ + struct addr_query *aquery = (struct addr_query *) arg; + struct hostent *host; + + if (status == ARES_SUCCESS) + { + status = ares_parse_ptr_reply(abuf, alen, &aquery->addr, + sizeof(struct in_addr), AF_INET, &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, host); + if (host) + ares_free_hostent(host); + free(aquery); +} + +static int file_lookup(struct in_addr *addr, struct hostent **host) +{ + FILE *fp; + int status; + +#ifdef WIN32 + + char PATH_HOSTS[MAX_PATH]; + if (IsNT) { + GetSystemDirectory(PATH_HOSTS, MAX_PATH); + strcat(PATH_HOSTS, PATH_HOSTS_NT); + } else { + GetWindowsDirectory(PATH_HOSTS, MAX_PATH); + strcat(PATH_HOSTS, PATH_HOSTS_9X); + } + +#endif + + fp = fopen(PATH_HOSTS, "r"); + if (!fp) + return ARES_ENOTFOUND; + + while ((status = ares__get_hostent(fp, host)) == ARES_SUCCESS) + { + if (memcmp((*host)->h_addr, addr, sizeof(struct in_addr)) == 0) + break; + ares_free_hostent(*host); + } + fclose(fp); + if (status == ARES_EOF) + status = ARES_ENOTFOUND; + if (status != ARES_SUCCESS) + *host = NULL; + return status; +} |