busybox/networking/ipcalc.c

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/* vi: set sw=4 ts=4: */
/*
* Mini ipcalc implementation for busybox
*
* By Jordan Crouse <jordan@cosmicpenguin.net>
* Stephan Linz <linz@li-pro.net>
*
* This is a complete reimplementation of the ipcalc program
* from Red Hat. I didn't look at their source code, but there
* is no denying that this is a loving reimplementation
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <sys/socket.h>
#include <arpa/inet.h>
#include "libbb.h"
#define CLASS_A_NETMASK ntohl(0xFF000000)
#define CLASS_B_NETMASK ntohl(0xFFFF0000)
#define CLASS_C_NETMASK ntohl(0xFFFFFF00)
static unsigned long get_netmask(unsigned long ipaddr)
{
ipaddr = htonl(ipaddr);
if ((ipaddr & 0xC0000000) == 0xC0000000)
return CLASS_C_NETMASK;
else if ((ipaddr & 0x80000000) == 0x80000000)
return CLASS_B_NETMASK;
else if ((ipaddr & 0x80000000) == 0)
return CLASS_A_NETMASK;
else
return 0;
}
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#if ENABLE_FEATURE_IPCALC_FANCY
static int get_prefix(unsigned long netmask)
{
unsigned long msk = 0x80000000;
int ret = 0;
netmask = htonl(netmask);
while (msk) {
if (netmask & msk)
ret++;
msk >>= 1;
}
return ret;
}
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#else
int get_prefix(unsigned long netmask);
#endif
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#define NETMASK 0x01
#define BROADCAST 0x02
#define NETWORK 0x04
#define NETPREFIX 0x08
#define HOSTNAME 0x10
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#define SILENT 0x20
#if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
static const char ipcalc_longopts[] ALIGN1 =
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"netmask\0" No_argument "m"
"broadcast\0" No_argument "b"
"network\0" No_argument "n"
# if ENABLE_FEATURE_IPCALC_FANCY
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"prefix\0" No_argument "p"
"hostname\0" No_argument "h"
"silent\0" No_argument "s"
# endif
;
#endif
int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int ipcalc_main(int argc, char **argv)
{
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unsigned opt;
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int have_netmask = 0;
in_addr_t netmask, broadcast, network, ipaddr;
struct in_addr a;
char *ipstr;
#if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
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applet_long_options = ipcalc_longopts;
#endif
opt = getopt32(argv, "mbn" USE_FEATURE_IPCALC_FANCY("phs"));
argc -= optind;
argv += optind;
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if (opt & (BROADCAST | NETWORK | NETPREFIX)) {
if (argc > 2 || argc <= 0)
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bb_show_usage();
} else {
if (argc != 1)
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bb_show_usage();
}
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if (opt & SILENT)
logmode = LOGMODE_NONE; /* Suppress error_msg() output */
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ipstr = argv[0];
if (ENABLE_FEATURE_IPCALC_FANCY) {
unsigned long netprefix = 0;
char *prefixstr;
prefixstr = ipstr;
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while (*prefixstr) {
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if (*prefixstr == '/') {
*prefixstr = (char)0;
prefixstr++;
if (*prefixstr) {
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unsigned msk;
netprefix = xatoul_range(prefixstr, 0, 32);
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netmask = 0;
msk = 0x80000000;
while (netprefix > 0) {
netmask |= msk;
msk >>= 1;
netprefix--;
}
netmask = htonl(netmask);
/* Even if it was 0, we will signify that we have a netmask. This allows */
/* for specification of default routes, etc which have a 0 netmask/prefix */
have_netmask = 1;
}
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break;
}
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prefixstr++;
}
}
ipaddr = inet_aton(ipstr, &a);
if (ipaddr == 0) {
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bb_error_msg_and_die("bad IP address: %s", argv[0]);
}
ipaddr = a.s_addr;
if (argc == 2) {
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if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
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bb_error_msg_and_die("use prefix or netmask, not both");
}
netmask = inet_aton(argv[1], &a);
if (netmask == 0) {
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bb_error_msg_and_die("bad netmask: %s", argv[1]);
}
netmask = a.s_addr;
} else {
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/* JHC - If the netmask wasn't provided then calculate it */
if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
netmask = get_netmask(ipaddr);
}
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if (opt & NETMASK) {
printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
}
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if (opt & BROADCAST) {
broadcast = (ipaddr & netmask) | ~netmask;
printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
}
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if (opt & NETWORK) {
network = ipaddr & netmask;
printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
}
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if (ENABLE_FEATURE_IPCALC_FANCY) {
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if (opt & NETPREFIX) {
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printf("PREFIX=%i\n", get_prefix(netmask));
}
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if (opt & HOSTNAME) {
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struct hostent *hostinfo;
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hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
if (!hostinfo) {
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bb_herror_msg_and_die("cannot find hostname for %s", argv[0]);
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}
str_tolower(hostinfo->h_name);
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printf("HOSTNAME=%s\n", hostinfo->h_name);
}
}
return EXIT_SUCCESS;
}