/* * express an address range as a subnet (if possible) * Copyright (C) 2000 Henry Spencer. * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Library General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at your * option) any later version. See . * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public * License for more details. * * RCSID $Id: rangetosubnet.c,v 1.1 2004/03/15 20:35:26 as Exp $ */ #include "internal.h" #include "freeswan.h" /* - rangetosubnet - turn an address range into a subnet, if possible * * A range which is a valid subnet will have a network part which is the * same in the from value and the to value, followed by a host part which * is all 0 in the from value and all 1 in the to value. */ err_t rangetosubnet(from, to, dst) const ip_address *from; const ip_address *to; ip_subnet *dst; { unsigned const char *fp; unsigned const char *tp; unsigned fb; unsigned tb; unsigned const char *f; unsigned const char *t; size_t n; size_t n2; int i; int nnet; unsigned m; if (addrtypeof(from) != addrtypeof(to)) return "mismatched address types"; n = addrbytesptr(from, &fp); if (n == 0) return "unknown address type"; n2 = addrbytesptr(to, &tp); if (n != n2) return "internal size mismatch in rangetosubnet"; f = fp; t = tp; nnet = 0; for (i = n; i > 0 && *f == *t; i--, f++, t++) nnet += 8; if (i > 0 && !(*f == 0x00 && *t == 0xff)) { /* mid-byte bdry. */ fb = *f++; tb = *t++; i--; m = 0x80; while ((fb&m) == (tb&m)) { fb &= ~m; tb |= m; m >>= 1; nnet++; } if (fb != 0x00 || tb != 0xff) return "not a valid subnet"; } for (; i > 0 && *f == 0x00 && *t == 0xff; i--, f++, t++) continue; if (i != 0) return "invalid subnet"; return initsubnet(from, nnet, 'x', dst); } #ifdef RANGETOSUBNET_MAIN #include void regress(void); int main(int argc, char *argv[]) { ip_address start; ip_address stop; ip_subnet sub; char buf[100]; const char *oops; size_t n; int af; int i; if (argc == 2 && strcmp(argv[1], "-r") == 0) { regress(); fprintf(stderr, "regress() returned?!?\n"); exit(1); } if (argc < 3) { fprintf(stderr, "Usage: %s [-6] start stop\n", argv[0]); fprintf(stderr, " or: %s -r\n", argv[0]); exit(2); } af = AF_INET; i = 1; if (strcmp(argv[i], "-6") == 0) { af = AF_INET6; i++; } oops = ttoaddr(argv[i], 0, af, &start); if (oops != NULL) { fprintf(stderr, "%s: start conversion failed: %s\n", argv[0], oops); exit(1); } oops = ttoaddr(argv[i+1], 0, af, &stop); if (oops != NULL) { fprintf(stderr, "%s: stop conversion failed: %s\n", argv[0], oops); exit(1); } oops = rangetosubnet(&start, &stop, &sub); if (oops != NULL) { fprintf(stderr, "%s: rangetosubnet failed: %s\n", argv[0], oops); exit(1); } n = subnettot(&sub, 0, buf, sizeof(buf)); if (n > sizeof(buf)) { fprintf(stderr, "%s: reverse conversion", argv[0]); fprintf(stderr, " failed: need %ld bytes, have only %ld\n", (long)n, (long)sizeof(buf)); exit(1); } printf("%s\n", buf); exit(0); } struct rtab { int family; char *start; char *stop; char *output; /* NULL means error expected */ } rtab[] = { {4, "1.2.3.0", "1.2.3.255", "1.2.3.0/24"}, {4, "1.2.3.0", "1.2.3.7", "1.2.3.0/29"}, {4, "1.2.3.240", "1.2.3.255", "1.2.3.240/28"}, {4, "0.0.0.0", "255.255.255.255", "0.0.0.0/0"}, {4, "1.2.3.4", "1.2.3.4", "1.2.3.4/32"}, {4, "1.2.3.0", "1.2.3.254", NULL}, {4, "1.2.3.0", "1.2.3.126", NULL}, {4, "1.2.3.0", "1.2.3.125", NULL}, {4, "1.2.0.0", "1.2.255.255", "1.2.0.0/16"}, {4, "1.2.0.0", "1.2.0.255", "1.2.0.0/24"}, {4, "1.2.255.0", "1.2.255.255", "1.2.255.0/24"}, {4, "1.2.255.0", "1.2.254.255", NULL}, {4, "1.2.255.1", "1.2.255.255", NULL}, {4, "1.2.0.1", "1.2.255.255", NULL}, {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"}, {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"}, {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"}, {4, NULL, NULL, NULL}, }; void regress() { struct rtab *r; int status = 0; ip_address start; ip_address stop; ip_subnet sub; char buf[100]; const char *oops; size_t n; int af; for (r = rtab; r->start != NULL; r++) { af = (r->family == 4) ? AF_INET : AF_INET6; oops = ttoaddr(r->start, 0, af, &start); if (oops != NULL) { printf("surprise failure converting `%s'\n", r->start); exit(1); } oops = ttoaddr(r->stop, 0, af, &stop); if (oops != NULL) { printf("surprise failure converting `%s'\n", r->stop); exit(1); } oops = rangetosubnet(&start, &stop, &sub); if (oops != NULL && r->output == NULL) {} /* okay, error expected */ else if (oops != NULL) { printf("`%s'-`%s' rangetosubnet failed: %s\n", r->start, r->stop, oops); status = 1; } else if (r->output == NULL) { printf("`%s'-`%s' rangetosubnet succeeded unexpectedly\n", r->start, r->stop); status = 1; } else { n = subnettot(&sub, 0, buf, sizeof(buf)); if (n > sizeof(buf)) { printf("`%s'-`%s' subnettot failed: need %ld\n", r->start, r->stop, (long)n); status = 1; } else if (strcmp(r->output, buf) != 0) { printf("`%s'-`%s' gave `%s', expected `%s'\n", r->start, r->stop, buf, r->output); status = 1; } } } exit(status); } #endif /* RANGETOSUBNET_MAIN */