udhcpc: reuse string constant; remove unneeded memset(0)
[oweals/busybox.git] / networking / ipcalc.c
index 94b747ef69beec5cc1b5e83ea39dceca90e5d1dd..3c8b8bfc910026c270161fd829178d61f7c623f6 100644 (file)
@@ -1,30 +1,49 @@
-/* vi: set sw=4 ts=4 ai: */
+/* 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 reimplentation of the ipcalc program
- * from Redhat.  I didn't look at their source code, but there
+ * 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 source tree.
  */
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <ctype.h>
-#include <getopt.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
+//usage:#define ipcalc_trivial_usage
+//usage:       "[OPTIONS] ADDRESS[[/]NETMASK] [NETMASK]"
+//usage:#define ipcalc_full_usage "\n\n"
+//usage:       "Calculate IP network settings from a IP address\n"
+//usage:       IF_FEATURE_IPCALC_LONG_OPTIONS(
+//usage:     "\n       -b,--broadcast  Display calculated broadcast address"
+//usage:     "\n       -n,--network    Display calculated network address"
+//usage:     "\n       -m,--netmask    Display default netmask for IP"
+//usage:       IF_FEATURE_IPCALC_FANCY(
+//usage:     "\n       -p,--prefix     Display the prefix for IP/NETMASK"
+//usage:     "\n       -h,--hostname   Display first resolved host name"
+//usage:     "\n       -s,--silent     Don't ever display error messages"
+//usage:       )
+//usage:       )
+//usage:       IF_NOT_FEATURE_IPCALC_LONG_OPTIONS(
+//usage:     "\n       -b      Display calculated broadcast address"
+//usage:     "\n       -n      Display calculated network address"
+//usage:     "\n       -m      Display default netmask for IP"
+//usage:       IF_FEATURE_IPCALC_FANCY(
+//usage:     "\n       -p      Display the prefix for IP/NETMASK"
+//usage:     "\n       -h      Display first resolved host name"
+//usage:     "\n       -s      Don't ever display error messages"
+//usage:       )
+//usage:       )
+
+#include "libbb.h"
+/* After libbb.h, because on some systems it needs other includes */
 #include <arpa/inet.h>
 
-#include "busybox.h"
-
-#define IPCALC_MSG(CMD,ALTCMD) if (mode & SILENT) {ALTCMD;} else {CMD;}
-
-#define CLASS_A_NETMASK        ntohl(0xFF000000)
-#define CLASS_B_NETMASK        ntohl(0xFFFF0000)
-#define CLASS_C_NETMASK        ntohl(0xFFFFFF00)
+#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)
 {
@@ -40,111 +59,155 @@ static unsigned long get_netmask(unsigned long ipaddr)
                return 0;
 }
 
+#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;
+}
+#else
+int get_prefix(unsigned long netmask);
+#endif
+
+
 #define NETMASK   0x01
 #define BROADCAST 0x02
 #define NETWORK   0x04
-#define HOSTNAME  0x08
-#define SILENT    0x10
-
-int ipcalc_main(int argc, char **argv)
-{
-       unsigned long mode;
-
-       unsigned long netmask = 0;
-       unsigned long broadcast;
-       unsigned long network;
-       unsigned long ipaddr;
-
-       static const struct option long_options[] = {
-               {"netmask", no_argument, NULL, 'n'},
-               {"broadcast", no_argument, NULL, 'b'},
-               {"network", no_argument, NULL, 'w'},
-#ifdef CONFIG_FEATURE_IPCALC_FANCY
-               {"hostname", no_argument, NULL, 'h'},
-               {"silent", no_argument, NULL, 's'},
+#define NETPREFIX 0x08
+#define HOSTNAME  0x10
+#define SILENT    0x20
+
+#if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
+       static const char ipcalc_longopts[] ALIGN1 =
+               "netmask\0"   No_argument "m" // netmask from IP (assuming complete class A, B, or C network)
+               "broadcast\0" No_argument "b" // broadcast from IP [netmask]
+               "network\0"   No_argument "n" // network from IP [netmask]
+# if ENABLE_FEATURE_IPCALC_FANCY
+               "prefix\0"    No_argument "p" // prefix from IP[/prefix] [netmask]
+               "hostname\0"  No_argument "h" // hostname from IP
+               "silent\0"    No_argument "s" // don’t ever display error messages
+# endif
+               ;
 #endif
-               {NULL, 0, NULL, 0}
-       };
 
-       bb_applet_long_options = long_options;
-       mode = bb_getopt_ulflags(argc, argv,
-#ifdef CONFIG_FEATURE_IPCALC_FANCY
-                                                         "nbwhs");
-#else
-                                                         "nbw");
+int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int ipcalc_main(int argc UNUSED_PARAM, char **argv)
+{
+       unsigned opt;
+       bool have_netmask = 0;
+       struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr;
+       /* struct in_addr { in_addr_t s_addr; }  and  in_addr_t
+        * (which in turn is just a typedef to uint32_t)
+        * are essentially the same type. A few macros for less verbosity: */
+#define netmask   (s_netmask.s_addr)
+#define broadcast (s_broadcast.s_addr)
+#define network   (s_network.s_addr)
+#define ipaddr    (s_ipaddr.s_addr)
+       char *ipstr;
+
+#if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
+       applet_long_options = ipcalc_longopts;
 #endif
-       if (mode & (BROADCAST | NETWORK)) {
-               if (argc - optind > 2) {
-                       bb_show_usage();
-               }
-       } else {
-               if (argc - optind != 1) {
+       opt_complementary = "-1:?2"; /* minimum 1 arg, maximum 2 args */
+       opt = getopt32(argv, "mbn" IF_FEATURE_IPCALC_FANCY("phs"));
+       argv += optind;
+       if (opt & SILENT)
+               logmode = LOGMODE_NONE; /* suppress error_msg() output */
+       opt &= ~SILENT;
+       if (!(opt & (BROADCAST | NETWORK | NETPREFIX))) {
+               /* if no options at all or
+                * (no broadcast,network,prefix) and (two args)... */
+               if (!opt || argv[1])
                        bb_show_usage();
-               }
        }
 
-       ipaddr = inet_addr(argv[optind]);
-
-       if (ipaddr == INADDR_NONE) {
-               IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[optind]),
-                                  exit(EXIT_FAILURE));
-       }
-
-
-       if (argc - optind == 2) {
-               netmask = inet_addr(argv[optind + 1]);
+       ipstr = argv[0];
+       if (ENABLE_FEATURE_IPCALC_FANCY) {
+               unsigned long netprefix = 0;
+               char *prefixstr;
+
+               prefixstr = ipstr;
+
+               while (*prefixstr) {
+                       if (*prefixstr == '/') {
+                               *prefixstr++ = '\0';
+                               if (*prefixstr) {
+                                       unsigned msk;
+                                       netprefix = xatoul_range(prefixstr, 0, 32);
+                                       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;
+                               }
+                               break;
+                       }
+                       prefixstr++;
+               }
        }
 
-       if (ipaddr == INADDR_NONE) {
-               IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[optind + 1]),
-                                  exit(EXIT_FAILURE));
+       if (inet_aton(ipstr, &s_ipaddr) == 0) {
+               bb_error_msg_and_die("bad IP address: %s", argv[0]);
        }
 
-       /* JHC - If the netmask wasn't provided then calculate it */
-       if (!netmask) {
-               netmask = get_netmask(ipaddr);
+       if (argv[1]) {
+               if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
+                       bb_error_msg_and_die("use prefix or netmask, not both");
+               }
+               if (inet_aton(argv[1], &s_netmask) == 0) {
+                       bb_error_msg_and_die("bad netmask: %s", argv[1]);
+               }
+       } else {
+               /* JHC - If the netmask wasn't provided then calculate it */
+               if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
+                       netmask = get_netmask(ipaddr);
        }
 
-       if (mode & NETMASK) {
-               printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
+       if (opt & NETMASK) {
+               printf("NETMASK=%s\n", inet_ntoa(s_netmask));
        }
 
-       if (mode & BROADCAST) {
+       if (opt & BROADCAST) {
                broadcast = (ipaddr & netmask) | ~netmask;
-               printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
+               printf("BROADCAST=%s\n", inet_ntoa(s_broadcast));
        }
 
-       if (mode & NETWORK) {
+       if (opt & NETWORK) {
                network = ipaddr & netmask;
-               printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
+               printf("NETWORK=%s\n", inet_ntoa(s_network));
        }
-#ifdef CONFIG_FEATURE_IPCALC_FANCY
-       if (mode & HOSTNAME) {
-               struct hostent *hostinfo;
-               int x;
-
-               hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
-               if (!hostinfo) {
-                       IPCALC_MSG(bb_herror_msg_and_die(
-                               "cannot find hostname for %s", argv[optind]),);
-                       exit(EXIT_FAILURE);
-               }
-               for (x = 0; hostinfo->h_name[x]; x++) {
-                       hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
+
+       if (ENABLE_FEATURE_IPCALC_FANCY) {
+               if (opt & NETPREFIX) {
+                       printf("PREFIX=%i\n", get_prefix(netmask));
                }
 
-               printf("HOSTNAME=%s\n", hostinfo->h_name);
+               if (opt & HOSTNAME) {
+                       struct hostent *hostinfo;
+
+                       hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
+                       if (!hostinfo) {
+                               bb_herror_msg_and_die("can't find hostname for %s", argv[0]);
+                       }
+                       str_tolower(hostinfo->h_name);
+
+                       printf("HOSTNAME=%s\n", hostinfo->h_name);
+               }
        }
-#endif
 
        return EXIT_SUCCESS;
 }
-
-/* END CODE */
-/*
-Local Variables:
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/