-/*
- * Copyright (c) 1997-2003 Red Hat, Inc. All rights reserved.
- *
- * This software may be freely redistributed under the terms of the GNU
- * public license.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *
- * Authors:
- * Erik Troan <ewt@redhat.com>
- * Preston Brown <pbrown@redhat.com>
- */
-
-
-#include <ctype.h>
-#include <popt.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/socket.h>
-#include <sys/types.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <netdb.h>
-
-/*!
- \def IPBITS
- \brief the number of bits in an IP address.
-*/
-#define IPBITS (sizeof(u_int32_t) * 8)
-/*!
- \def IPBYTES
- \brief the number of bytes in an IP address.
-*/
-#define IPBYTES (sizeof(u_int32_t))
-
-
-/*!
- \file ipcalc.c
- \brief provides utilities for manipulating IP addresses.
-
- ipcalc provides utilities and a front-end command line interface for
- manipulating IP addresses, and calculating various aspects of an ip
- address/netmask/network address/prefix/etc.
-
- Functionality can be accessed from other languages from the library
- interface, documented here. To use ipcalc from the shell, read the
- ipcalc(1) manual page.
-
- When passing parameters to the various functions, take note of whether they
- take host byte order or network byte order. Most take host byte order, and
- return host byte order, but there are some exceptions.
-
-*/
-
-/*!
- \fn u_int32_t prefix2mask(int bits)
- \brief creates a netmask from a specified number of bits
-
- This function converts a prefix length to a netmask. As CIDR (classless
- internet domain internet domain routing) has taken off, more an more IP
- addresses are being specified in the format address/prefix
- (i.e. 192.168.2.3/24, with a corresponding netmask 255.255.255.0). If you
- need to see what netmask corresponds to the prefix part of the address, this
- is the function. See also \ref mask2prefix.
-
- \param prefix is the number of bits to create a mask for.
- \return a network mask, in network byte order.
-*/
-u_int32_t prefix2mask(int prefix) {
- return htonl(~((1 << (32 - prefix)) - 1));
-}
-
-/*!
- \fn int mask2prefix(u_int32_t mask)
- \brief calculates the number of bits masked off by a netmask.
-
- This function calculates the significant bits in an IP address as specified by
- a netmask. See also \ref prefix2mask.
-
- \param mask is the netmask, specified as an u_int32_teger in network byte order.
- \return the number of significant bits. */
-int mask2prefix(u_int32_t mask)
-{
- int i;
- int count = IPBITS;
-
- for (i = 0; i < IPBITS; i++) {
- if (!(ntohl(mask) & ((2 << i) - 1)))
- count--;
- }
-
- return count;
-}
-
-/*!
- \fn u_int32_t default_netmask(u_int32_t addr)
-
- \brief returns the default (canonical) netmask associated with specified IP
- address.
-
- When the Internet was originally set up, various ranges of IP addresses were
- segmented into three network classes: A, B, and C. This function will return
- a netmask that is associated with the IP address specified defining where it
- falls in the predefined classes.
-
- \param addr an IP address in network byte order.
- \return a netmask in network byte order. */
-u_int32_t default_netmask(u_int32_t addr)
-{
- if (((ntohl(addr) & 0xFF000000) >> 24) <= 127)
- return htonl(0xFF000000);
- else if (((ntohl(addr) & 0xFF000000) >> 24) <= 191)
- return htonl(0xFFFF0000);
- else
- return htonl(0xFFFFFF00);
-}
-
-/*!
- \fn u_int32_t calc_broadcast(u_int32_t addr, int prefix)
-
- \brief calculate broadcast address given an IP address and a prefix length.
-
- \param addr an IP address in network byte order.
- \param prefix a prefix length.
-
- \return the calculated broadcast address for the network, in network byte
- order.
-*/
-u_int32_t calc_broadcast(u_int32_t addr,
- int prefix)
-{
- return (addr & prefix2mask(prefix)) | ~prefix2mask(prefix);
-}
-
-/*!
- \fn u_int32_t calc_network(u_int32_t addr, int prefix)
- \brief calculates the network address for a specified address and prefix.
-
- \param addr an IP address, in network byte order
- \param prefix the network prefix
- \return the base address of the network that addr is associated with, in
- network byte order.
-*/
-u_int32_t calc_network(u_int32_t addr, int prefix)
-{
- return (addr & prefix2mask(prefix));
-}
-
-/*!
- \fn const char *get_hostname(u_int32_t addr)
- \brief returns the hostname associated with the specified IP address
-
- \param addr an IP address to find a hostname for, in network byte order
-
- \return a hostname, or NULL if one cannot be determined. Hostname is stored
- in a static buffer that may disappear at any time, the caller should copy the
- data if it needs permanent storage.
-*/
-const char *get_hostname(u_int32_t addr)
-{
- struct hostent * hostinfo;
- int x;
-
- hostinfo = gethostbyaddr((char *) &addr, sizeof(addr), AF_INET);
- if (!hostinfo)
- return NULL;
-
- for (x=0; hostinfo->h_name[x]; x++) {
- hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
- }
- return hostinfo->h_name;
-}
-
-/*!
- \fn main(int argc, const char **argv)
- \brief wrapper program for ipcalc functions.
-
- This is a wrapper program for the functions that the ipcalc library provides.
- It can be used from shell scripts or directly from the command line.
-
- For more information, please see the ipcalc(1) man page.
-*/
-int main(int argc, const char **argv) {
- int showBroadcast = 0, showPrefix = 0, showNetwork = 0;
- int showHostname = 0, showNetmask = 0;
- int beSilent = 0;
- int rc;
- poptContext optCon;
- char *ipStr, *prefixStr, *netmaskStr, *hostName, *chptr;
- struct in_addr ip, netmask, network, broadcast;
- int prefix = 0;
- char errBuf[250];
- struct poptOption optionsTable[] = {
- { "broadcast", 'b', 0, &showBroadcast, 0,
- "Display calculated broadcast address", },
- { "hostname", 'h', 0, &showHostname, 0,
- "Show hostname determined via DNS" },
- { "netmask", 'm', 0, &showNetmask, 0,
- "Display default netmask for IP (class A, B, or C)" },
- { "network", 'n', 0, &showNetwork, 0,
- "Display network address", },
- { "prefix", 'p', 0, &showPrefix, 0,
- "Display network prefix", },
- { "silent", 's', 0, &beSilent, 0,
- "Don't ever display error messages " },
- POPT_AUTOHELP
- { NULL, '\0', 0, 0, 0, NULL, NULL }
- };
-
- optCon = poptGetContext("ipcalc", argc, argv, optionsTable, 0);
- poptReadDefaultConfig(optCon, 1);
-
- if ((rc = poptGetNextOpt(optCon)) < -1) {
- if (!beSilent) {
- fprintf(stderr, "ipcalc: bad argument %s: %s\n",
- poptBadOption(optCon, POPT_BADOPTION_NOALIAS),
- poptStrerror(rc));
- poptPrintHelp(optCon, stderr, 0);
- }
- return 1;
- }
-
- if (!(ipStr = (char *) poptGetArg(optCon))) {
- if (!beSilent) {
- fprintf(stderr, "ipcalc: ip address expected\n");
- poptPrintHelp(optCon, stderr, 0);
- }
- return 1;
- }
-
- if (strchr(ipStr,'/') != NULL) {
- prefixStr = strchr(ipStr, '/') + 1;
- prefixStr--;
- *prefixStr = '\0'; /* fix up ipStr */
- prefixStr++;
- } else
- prefixStr = NULL;
-
- if (prefixStr != NULL) {
- prefix = atoi(prefixStr);
- if (prefix == 0) {
- if (!beSilent)
- fprintf(stderr, "ipcalc: bad prefix: %s\n",
- prefixStr);
- return 1;
- }
- }
-
- if (showBroadcast || showNetwork || showPrefix) {
- if (!(netmaskStr = (char *) poptGetArg(optCon)) &&
- (prefix == 0)) {
- if (!beSilent) {
- fprintf(stderr, "ipcalc: netmask or prefix expected\n");
- poptPrintHelp(optCon, stderr, 0);
- }
- return 1;
- } else if (netmaskStr && prefix != 0) {
- if (!beSilent) {
- fprintf(stderr, "ipcalc: both netmask and prefix specified\n");
- poptPrintHelp(optCon, stderr, 0);
- }
- return 1;
- } else if (netmaskStr) {
- if (!inet_aton(netmaskStr, &netmask)) {
- if (!beSilent)
- fprintf(stderr, "ipcalc: bad netmask: %s\n",
- netmaskStr);
- return 1;
- }
- prefix = mask2prefix(netmask.s_addr);
- }
- }
-
- if ((chptr = (char *) poptGetArg(optCon))) {
- if (!beSilent) {
- fprintf(stderr, "ipcalc: unexpected argument: %s\n", chptr);
- poptPrintHelp(optCon, stderr, 0);
- }
- return 1;
- }
-
- /* Handle CIDR entries such as 172/8 */
- if (prefix) {
- char *tmp = ipStr;
- int i;
-
- for(i=3; i> 0; i--) {
- tmp = strchr(tmp,'.');
- if (!tmp)
- break;
- else
- tmp++;
- }
- tmp = NULL;
- for (; i>0; i--) {
- tmp = malloc(strlen(ipStr) + 3);
- sprintf(tmp,"%s.0",ipStr);
- ipStr = tmp;
- }
- }
-
- if (!inet_aton(ipStr, (struct in_addr *) &ip)) {
- if (!beSilent)
- fprintf(stderr, "ipcalc: bad ip address: %s\n", ipStr);
- return 1;
- }
-
-
- if (!(showNetmask|showPrefix|showBroadcast|showNetwork|showHostname)) {
- poptPrintHelp(optCon, stderr, 0);
- return 1;
- }
-
- poptFreeContext(optCon);
-
- /* we know what we want to display now, so display it. */
-
- if (showNetmask) {
- if (prefix) {
- netmask.s_addr = prefix2mask(prefix);
- } else {
- netmask.s_addr = default_netmask(ip.s_addr);
- prefix = mask2prefix(netmask.s_addr);
- }
-
- printf("NETMASK=%s\n", inet_ntoa(netmask));
- }
-
- if (showPrefix) {
- if (!prefix)
- prefix = mask2prefix(ip.s_addr);
- printf("PREFIX=%d\n", prefix);
- }
-
- if (showBroadcast) {
- broadcast.s_addr = calc_broadcast(ip.s_addr, prefix);
- printf("BROADCAST=%s\n", inet_ntoa(broadcast));
- }
-
- if (showNetwork) {
- network.s_addr = calc_network(ip.s_addr, prefix);
- printf("NETWORK=%s\n", inet_ntoa(network));
- }
-
- if (showHostname) {
- if ((hostName = (char *) get_hostname(ip.s_addr)) == NULL) {
- if (!beSilent) {
- sprintf(errBuf, "ipcalc: cannot find hostname for %s", ipStr);
- herror(errBuf);
- }
- return 1;
- }
-
- printf("HOSTNAME=%s\n", hostName);
- }
-
- return 0;
-}
TLD / rc-scripts.git / commitdiff