freeswan/lib/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 1.5 2000/09/08 18:03:45 henry 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();
  89
  90 int
  91 main(argc, argv)
  92 int argc;
  93 char *argv[];
  94 {
  95         ip_address start;
  96         ip_address stop;
  97         ip_subnet sub;
  98         char buf[100];
  99         const char *oops;
 100         size_t n;
 101         int af;
 102         int i;
 103
 104         if (argc == 2 && strcmp(argv[1], "-r") == 0) {
 105                 regress();
 106                 fprintf(stderr, "regress() returned?!?\n");
 107                 exit(1);
 108         }
 109
 110         if (argc < 3) {
 111                 fprintf(stderr, "Usage: %s [-6] start stop\n", argv[0]);
 112                 fprintf(stderr, "   or: %s -r\n", argv[0]);
 113                 exit(2);
 114         }
 115
 116         af = AF_INET;
 117         i = 1;
 118         if (strcmp(argv[i], "-6") == 0) {
 119                 af = AF_INET6;
 120                 i++;
 121         }
 122
 123         oops = ttoaddr(argv[i], 0, af, &start);
 124         if (oops != NULL) {
 125                 fprintf(stderr, "%s: start conversion failed: %s\n", argv[0], oops);
 126                 exit(1);
 127         }
 128         oops = ttoaddr(argv[i+1], 0, af, &stop);
 129         if (oops != NULL) {
 130                 fprintf(stderr, "%s: stop conversion failed: %s\n", argv[0], oops);
 131                 exit(1);
 132         }
 133         oops = rangetosubnet(&start, &stop, &sub);
 134         if (oops != NULL) {
 135                 fprintf(stderr, "%s: rangetosubnet failed: %s\n", argv[0], oops);
 136                 exit(1);
 137         }
 138         n = subnettot(&sub, 0, buf, sizeof(buf));
 139         if (n > sizeof(buf)) {
 140                 fprintf(stderr, "%s: reverse conversion", argv[0]);
 141                 fprintf(stderr, " failed: need %ld bytes, have only %ld\n",
 142                                                 (long)n, (long)sizeof(buf));
 143                 exit(1);
 144         }
 145         printf("%s\n", buf);
 146
 147         exit(0);
 148 }
 149
 150 struct rtab {
 151         int family;
 152         char *start;
 153         char *stop;
 154         char *output;                   /* NULL means error expected */
 155 } rtab[] = {
 156         4, "1.2.3.0",           "1.2.3.255",            "1.2.3.0/24",
 157         4, "1.2.3.0",           "1.2.3.7",              "1.2.3.0/29",
 158         4, "1.2.3.240",         "1.2.3.255",            "1.2.3.240/28",
 159         4, "0.0.0.0",           "255.255.255.255",      "0.0.0.0/0",
 160         4, "1.2.3.4",           "1.2.3.4",              "1.2.3.4/32",
 161         4, "1.2.3.0",           "1.2.3.254",            NULL,
 162         4, "1.2.3.0",           "1.2.3.126",            NULL,
 163         4, "1.2.3.0",           "1.2.3.125",            NULL,
 164         4, "1.2.0.0",           "1.2.255.255",          "1.2.0.0/16",
 165         4, "1.2.0.0",           "1.2.0.255",            "1.2.0.0/24",
 166         4, "1.2.255.0",         "1.2.255.255",          "1.2.255.0/24",
 167         4, "1.2.255.0",         "1.2.254.255",          NULL,
 168         4, "1.2.255.1",         "1.2.255.255",          NULL,
 169         4, "1.2.0.1",           "1.2.255.255",          NULL,
 170         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",
 171         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",
 172         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",
 173         4, NULL,                NULL,                   NULL,
 174 };
 175
 176 void
 177 regress()
 178 {
 179         struct rtab *r;
 180         int status = 0;
 181         ip_address start;
 182         ip_address stop;
 183         ip_subnet sub;
 184         char buf[100];
 185         const char *oops;
 186         size_t n;
 187         int af;
 188
 189         for (r = rtab; r->start != NULL; r++) {
 190                 af = (r->family == 4) ? AF_INET : AF_INET6;
 191                 oops = ttoaddr(r->start, 0, af, &start);
 192                 if (oops != NULL) {
 193                         printf("surprise failure converting `%s'\n", r->start);
 194                         exit(1);
 195                 }
 196                 oops = ttoaddr(r->stop, 0, af, &stop);
 197                 if (oops != NULL) {
 198                         printf("surprise failure converting `%s'\n", r->stop);
 199                         exit(1);
 200                 }
 201                 oops = rangetosubnet(&start, &stop, &sub);
 202                 if (oops != NULL && r->output == NULL)
 203                         {}              /* okay, error expected */
 204                 else if (oops != NULL) {
 205                         printf("`%s'-`%s' rangetosubnet failed: %s\n",
 206                                                 r->start, r->stop, oops);
 207                         status = 1;
 208                 } else if (r->output == NULL) {
 209                         printf("`%s'-`%s' rangetosubnet succeeded unexpectedly\n",
 210                                                         r->start, r->stop);
 211                         status = 1;
 212                 } else {
 213                         n = subnettot(&sub, 0, buf, sizeof(buf));
 214                         if (n > sizeof(buf)) {
 215                                 printf("`%s'-`%s' subnettot failed:  need %ld\n",
 216                                                 r->start, r->stop, (long)n);
 217                                 status = 1;
 218                         } else if (strcmp(r->output, buf) != 0) {
 219                                 printf("`%s'-`%s' gave `%s', expected `%s'\n",
 220                                         r->start, r->stop, buf, r->output);
 221                                 status = 1;
 222                         }
 223                 }
 224         }
 225         exit(status);
 226 }
 227
 228 #endif /* RANGETOSUBNET_MAIN */