linux/lib/libfreeswan/rangetosubnet.c

   1 /*
   2  * express an address range as a subnet (if possible)
   3  * Copyright (C) 2000  Henry Spencer.
   4  *
   5  * This library is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU Library General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/lgpl.txt>.
   9  *
  10  * This library is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
  13  * License for more details.
  14  *
  15  * RCSID $Id: rangetosubnet.c,v 1.1 2004/03/15 20:35:26 as Exp $
  16  */
  17 #include "internal.h"
  18 #include "freeswan.h"
  19
  20 /*
  21  - rangetosubnet - turn an address range into a subnet, if possible
  22  *
  23  * A range which is a valid subnet will have a network part which is the
  24  * same in the from value and the to value, followed by a host part which
  25  * is all 0 in the from value and all 1 in the to value.
  26  */
  27 err_t
  28 rangetosubnet(from, to, dst)
  29 const ip_address *from;
  30 const ip_address *to;
  31 ip_subnet *dst;
  32 {
  33         unsigned const char *fp;
  34         unsigned const char *tp;
  35         unsigned fb;
  36         unsigned tb;
  37         unsigned const char *f;
  38         unsigned const char *t;
  39         size_t n;
  40         size_t n2;
  41         int i;
  42         int nnet;
  43         unsigned m;
  44
  45         if (addrtypeof(from) != addrtypeof(to))
  46                 return "mismatched address types";
  47         n = addrbytesptr(from, &fp);
  48         if (n == 0)
  49                 return "unknown address type";
  50         n2 = addrbytesptr(to, &tp);
  51         if (n != n2)
  52                 return "internal size mismatch in rangetosubnet";
  53
  54         f = fp;
  55         t = tp;
  56         nnet = 0;
  57         for (i = n; i > 0 && *f == *t; i--, f++, t++)
  58                 nnet += 8;
  59         if (i > 0 && !(*f == 0x00 && *t == 0xff)) {     /* mid-byte bdry. */
  60                 fb = *f++;
  61                 tb = *t++;
  62                 i--;
  63                 m = 0x80;
  64                 while ((fb&m) == (tb&m)) {
  65                         fb &= ~m;
  66                         tb |= m;
  67                         m >>= 1;
  68                         nnet++;
  69                 }
  70                 if (fb != 0x00 || tb != 0xff)
  71                         return "not a valid subnet";
  72         }
  73         for (; i > 0 && *f == 0x00 && *t == 0xff; i--, f++, t++)
  74                 continue;
  75
  76         if (i != 0)
  77                 return "invalid subnet";
  78
  79         return initsubnet(from, nnet, 'x', dst);
  80 }
  81
  82
  83
  84 #ifdef RANGETOSUBNET_MAIN
  85
  86 #include <stdio.h>
  87
  88 void regress(void);
  89
  90 int
  91 main(int argc, char *argv[])
  92 {
  93         ip_address start;
  94         ip_address stop;
  95         ip_subnet sub;
  96         char buf[100];
  97         const char *oops;
  98         size_t n;
  99         int af;
 100         int i;
 101
 102         if (argc == 2 && strcmp(argv[1], "-r") == 0) {
 103                 regress();
 104                 fprintf(stderr, "regress() returned?!?\n");
 105                 exit(1);
 106         }
 107
 108         if (argc < 3) {
 109                 fprintf(stderr, "Usage: %s [-6] start stop\n", argv[0]);
 110                 fprintf(stderr, "   or: %s -r\n", argv[0]);
 111                 exit(2);
 112         }
 113
 114         af = AF_INET;
 115         i = 1;
 116         if (strcmp(argv[i], "-6") == 0) {
 117                 af = AF_INET6;
 118                 i++;
 119         }
 120
 121         oops = ttoaddr(argv[i], 0, af, &start);
 122         if (oops != NULL) {
 123                 fprintf(stderr, "%s: start conversion failed: %s\n", argv[0], oops);
 124                 exit(1);
 125         }
 126         oops = ttoaddr(argv[i+1], 0, af, &stop);
 127         if (oops != NULL) {
 128                 fprintf(stderr, "%s: stop conversion failed: %s\n", argv[0], oops);
 129                 exit(1);
 130         }
 131         oops = rangetosubnet(&start, &stop, &sub);
 132         if (oops != NULL) {
 133                 fprintf(stderr, "%s: rangetosubnet failed: %s\n", argv[0], oops);
 134                 exit(1);
 135         }
 136         n = subnettot(&sub, 0, buf, sizeof(buf));
 137         if (n > sizeof(buf)) {
 138                 fprintf(stderr, "%s: reverse conversion", argv[0]);
 139                 fprintf(stderr, " failed: need %ld bytes, have only %ld\n",
 140                                                 (long)n, (long)sizeof(buf));
 141                 exit(1);
 142         }
 143         printf("%s\n", buf);
 144
 145         exit(0);
 146 }
 147
 148 struct rtab {
 149         int family;
 150         char *start;
 151         char *stop;
 152         char *output;                   /* NULL means error expected */
 153 } rtab[] = {
 154         {4, "1.2.3.0",          "1.2.3.255",            "1.2.3.0/24"},
 155         {4, "1.2.3.0",          "1.2.3.7",              "1.2.3.0/29"},
 156         {4, "1.2.3.240",        "1.2.3.255",            "1.2.3.240/28"},
 157         {4, "0.0.0.0",          "255.255.255.255",      "0.0.0.0/0"},
 158         {4, "1.2.3.4",          "1.2.3.4",              "1.2.3.4/32"},
 159         {4, "1.2.3.0",          "1.2.3.254",            NULL},
 160         {4, "1.2.3.0",          "1.2.3.126",            NULL},
 161         {4, "1.2.3.0",          "1.2.3.125",            NULL},
 162         {4, "1.2.0.0",          "1.2.255.255",          "1.2.0.0/16"},
 163         {4, "1.2.0.0",          "1.2.0.255",            "1.2.0.0/24"},
 164         {4, "1.2.255.0",                "1.2.255.255",  "1.2.255.0/24"},
 165         {4, "1.2.255.0",                "1.2.254.255",  NULL},
 166         {4, "1.2.255.1",                "1.2.255.255",  NULL},
 167         {4, "1.2.0.1",          "1.2.255.255",          NULL},
 168         {6, "1:2:3:4:5:6:7:0",  "1:2:3:4:5:6:7:ffff",   "1:2:3:4:5:6:7:0/112"},
 169         {6, "1:2:3:4:5:6:7:0",  "1:2:3:4:5:6:7:fff",    "1:2:3:4:5:6:7:0/116"},
 170         {6, "1:2:3:4:5:6:7:f0", "1:2:3:4:5:6:7:ff",     "1:2:3:4:5:6:7:f0/124"},
 171         {4, NULL,               NULL,                   NULL},
 172 };
 173
 174 void
 175 regress()
 176 {
 177         struct rtab *r;
 178         int status = 0;
 179         ip_address start;
 180         ip_address stop;
 181         ip_subnet sub;
 182         char buf[100];
 183         const char *oops;
 184         size_t n;
 185         int af;
 186
 187         for (r = rtab; r->start != NULL; r++) {
 188                 af = (r->family == 4) ? AF_INET : AF_INET6;
 189                 oops = ttoaddr(r->start, 0, af, &start);
 190                 if (oops != NULL) {
 191                         printf("surprise failure converting `%s'\n", r->start);
 192                         exit(1);
 193                 }
 194                 oops = ttoaddr(r->stop, 0, af, &stop);
 195                 if (oops != NULL) {
 196                         printf("surprise failure converting `%s'\n", r->stop);
 197                         exit(1);
 198                 }
 199                 oops = rangetosubnet(&start, &stop, &sub);
 200                 if (oops != NULL && r->output == NULL)
 201                         {}              /* okay, error expected */
 202                 else if (oops != NULL) {
 203                         printf("`%s'-`%s' rangetosubnet failed: %s\n",
 204                                                 r->start, r->stop, oops);
 205                         status = 1;
 206                 } else if (r->output == NULL) {
 207                         printf("`%s'-`%s' rangetosubnet succeeded unexpectedly\n",
 208                                                         r->start, r->stop);
 209                         status = 1;
 210                 } else {
 211                         n = subnettot(&sub, 0, buf, sizeof(buf));
 212                         if (n > sizeof(buf)) {
 213                                 printf("`%s'-`%s' subnettot failed:  need %ld\n",
 214                                                 r->start, r->stop, (long)n);
 215                                 status = 1;
 216                         } else if (strcmp(r->output, buf) != 0) {
 217                                 printf("`%s'-`%s' gave `%s', expected `%s'\n",
 218                                         r->start, r->stop, buf, r->output);
 219                                 status = 1;
 220                         }
 221                 }
 222         }
 223         exit(status);
 224 }
 225
 226 #endif /* RANGETOSUBNET_MAIN */