/* * owipcalc - OpenWrt IP Calculator * * Copyright (C) 2012 Jo-Philipp Wich * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include #include #include #include #include #include #include struct cidr { uint8_t family; uint32_t prefix; union { struct in_addr v4; struct in6_addr v6; } addr; union { char v4[sizeof("255.255.255.255/255.255.255.255 ")]; char v6[sizeof("FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF/128 ")]; } buf; }; struct op { const char *name; const char *desc; struct { bool (*a1)(struct cidr *a); bool (*a2)(struct cidr *a, struct cidr *b); } f4; struct { bool (*a1)(struct cidr *a); bool (*a2)(struct cidr *a, struct cidr *b); } f6; }; static bool quiet = false; static bool printed = false; static struct cidr * cidr_parse4(const char *s) { char *p = NULL, *r; struct in_addr mask; struct cidr *addr = malloc(sizeof(struct cidr)); if (!addr || (strlen(s) >= sizeof(addr->buf.v4))) goto err; snprintf(addr->buf.v4, sizeof(addr->buf.v4), "%s", s); addr->family = AF_INET; if ((p = strchr(addr->buf.v4, '/')) != NULL) { *p++ = 0; if (strchr(p, '.') != NULL) { if (inet_pton(AF_INET, p, &mask) != 1) goto err; for (addr->prefix = 0; mask.s_addr; mask.s_addr >>= 1) addr->prefix += (mask.s_addr & 1); } else { addr->prefix = strtoul(p, &r, 10); if ((p == r) || (*r != 0) || (addr->prefix > 32)) goto err; } } else { addr->prefix = 32; } if (p == addr->buf.v4+1) memset(&addr->addr.v4, 0, sizeof(addr->addr.v4)); else if (inet_pton(AF_INET, addr->buf.v4, &addr->addr.v4) != 1) goto err; return addr; err: if (addr) free(addr); return NULL; } static bool cidr_add4(struct cidr *a, struct cidr *b) { uint32_t x = ntohl(a->addr.v4.s_addr); uint32_t y = ntohl(b->addr.v4.s_addr); if ((a->family != AF_INET) || (b->family != AF_INET)) return false; if ((uint32_t)(x + y) < x) { fprintf(stderr, "overflow during 'add'\n"); return false; } a->addr.v4.s_addr = htonl(x + y); return true; } static bool cidr_sub4(struct cidr *a, struct cidr *b) { uint32_t x = ntohl(a->addr.v4.s_addr); uint32_t y = ntohl(b->addr.v4.s_addr); if ((a->family != AF_INET) || (b->family != AF_INET)) return false; if ((uint32_t)(x - y) > x) { fprintf(stderr, "underflow during 'sub'\n"); return false; } a->addr.v4.s_addr = htonl(x - y); return true; } static bool cidr_network4(struct cidr *a) { a->addr.v4.s_addr &= htonl(~((1 << (32 - a->prefix)) - 1)); a->prefix = 32; return true; } static bool cidr_broadcast4(struct cidr *a) { a->addr.v4.s_addr |= htonl(((1 << (32 - a->prefix)) - 1)); a->prefix = 32; return true; } static bool cidr_contains4(struct cidr *a, struct cidr *b) { uint32_t net1 = a->addr.v4.s_addr & htonl(~((1 << (32 - a->prefix)) - 1)); uint32_t net2 = b->addr.v4.s_addr & htonl(~((1 << (32 - a->prefix)) - 1)); printed = true; if ((b->prefix >= a->prefix) && (net1 == net2)) { if (!quiet) printf("1\n"); return true; } else { if (!quiet) printf("0\n"); return false; } } static bool cidr_netmask4(struct cidr *a) { struct in_addr mask; char buf[sizeof("255.255.255.255 ")]; mask.s_addr = htonl(~((1 << (32 - a->prefix)) - 1)); if (!quiet) printf("%s\n", inet_ntop(AF_INET, &mask, buf, sizeof(buf))); printed = true; return true; } static bool cidr_private4(struct cidr *a) { uint32_t x = ntohl(a->addr.v4.s_addr); printed = true; if (((x >= 0x0A000000) && (x <= 0x0AFFFFFF)) || ((x >= 0xAC100000) && (x <= 0xAC1FFFFF)) || ((x >= 0xC0A80000) && (x <= 0xC0A8FFFF))) { if (!quiet) printf("1\n"); return true; } else { if (!quiet) printf("0\n"); return false; } } static bool cidr_linklocal4(struct cidr *a) { uint32_t x = ntohl(a->addr.v4.s_addr); printed = true; if ((x >= 0xA9FE0000) && (x <= 0xA9FEFFFF)) { if (!quiet) printf("1\n"); return true; } else { if (!quiet) printf("0\n"); return false; } } static bool cidr_print4(struct cidr *a) { char *p; if (a->family != AF_INET) return false; if (!(p = (char *)inet_ntop(AF_INET, &a->addr.v4, a->buf.v4, sizeof(a->buf.v4)))) return false; if (!quiet) printf("%s", p); if (!quiet && (a->prefix < 32)) printf("/%u", a->prefix); if (!quiet) printf("\n"); printed = true; return true; } static struct cidr * cidr_parse6(const char *s) { char *p = NULL, *r; struct cidr *addr = malloc(sizeof(struct cidr)); if (!addr || (strlen(s) >= sizeof(addr->buf.v6))) goto err; snprintf(addr->buf.v6, sizeof(addr->buf.v6), "%s", s); addr->family = AF_INET6; if ((p = strchr(addr->buf.v6, '/')) != NULL) { *p++ = 0; addr->prefix = strtoul(p, &r, 10); if ((p == r) || (*r != 0) || (addr->prefix > 128)) goto err; } else { addr->prefix = 128; } if (p == addr->buf.v6+1) memset(&addr->addr.v6, 0, sizeof(addr->addr.v6)); else if (inet_pton(AF_INET6, addr->buf.v6, &addr->addr.v6) != 1) goto err; return addr; err: if (addr) free(addr); return NULL; } static bool cidr_add6(struct cidr *a, struct cidr *b) { uint8_t idx = 15, carry = 0, overflow = 0; struct in6_addr *x = &a->addr.v6; struct in6_addr *y = &b->addr.v6; if ((a->family != AF_INET6) || (b->family != AF_INET6)) return false; do { overflow = !!((x->s6_addr[idx] + y->s6_addr[idx] + carry) >= 256); x->s6_addr[idx] += y->s6_addr[idx] + carry; carry = overflow; } while (idx-- > 0); if (carry) { fprintf(stderr, "overflow during 'add'\n"); return false; } return true; } static bool cidr_sub6(struct cidr *a, struct cidr *b) { uint8_t idx = 15, carry = 0, underflow = 0; struct in6_addr *x = &a->addr.v6; struct in6_addr *y = &b->addr.v6; if ((a->family != AF_INET6) || (b->family != AF_INET6)) return false; do { underflow = !!((x->s6_addr[idx] - y->s6_addr[idx] - carry) < 0); x->s6_addr[idx] -= y->s6_addr[idx] + carry; carry = underflow; } while (idx-- > 0); if (carry) { fprintf(stderr, "underflow during 'sub'\n"); return false; } return true; } static bool cidr_network6(struct cidr *a) { uint8_t i; for (i = 0; i < (128 - a->prefix) / 8; i++) a->addr.v6.s6_addr[15-i] = 0; if ((128 - a->prefix) % 8) a->addr.v6.s6_addr[15-i] &= ~((1 << ((128 - a->prefix) % 8)) - 1); return true; } static bool cidr_contains6(struct cidr *a, struct cidr *b) { struct in6_addr *x = &a->addr.v6; struct in6_addr *y = &b->addr.v6; uint8_t i = (128 - a->prefix) / 8; uint8_t m = ~((1 << ((128 - a->prefix) % 8)) - 1); uint8_t net1 = x->s6_addr[15-i] & m; uint8_t net2 = y->s6_addr[15-i] & m; printed = true; if ((b->prefix >= a->prefix) && (net1 == net2) && ((i == 15) || !memcmp(&x->s6_addr, &y->s6_addr, 15-i))) { if (!quiet) printf("1\n"); return true; } else { if (!quiet) printf("0\n"); return false; } } static bool cidr_linklocal6(struct cidr *a) { printed = true; if ((a->addr.v6.s6_addr[0] == 0xFE) && (a->addr.v6.s6_addr[1] >= 0x80) && (a->addr.v6.s6_addr[1] <= 0xBF)) { if (!quiet) printf("1\n"); return true; } else { if (!quiet) printf("0\n"); return false; } } static bool cidr_ula6(struct cidr *a) { printed = true; if ((a->addr.v6.s6_addr[0] >= 0xFC) && (a->addr.v6.s6_addr[0] <= 0xFD)) { if (!quiet) printf("1\n"); return true; } else { if (!quiet) printf("0\n"); return false; } } static bool cidr_print6(struct cidr *a) { char *p; if (a->family != AF_INET6) return NULL; if (!(p = (char *)inet_ntop(AF_INET6, &a->addr.v6, a->buf.v6, sizeof(a->buf.v6)))) return false; if (!quiet) printf("%s", p); if (!quiet && (a->prefix < 128)) printf("/%u", a->prefix); if (!quiet) printf("\n"); printed = true; return true; } static struct cidr * cidr_parse(const char *op, const char *s, int af_hint) { char *r; struct cidr *a; uint8_t i; uint32_t sum = strtoul(s, &r, 0); if ((r > s) && (*r == 0)) { a = malloc(sizeof(struct cidr)); if (!a) return NULL; if (af_hint == AF_INET) { a->family = AF_INET; a->prefix = 32; a->addr.v4.s_addr = htonl(sum); } else { a->family = AF_INET6; a->prefix = 128; for (i = 0; i <= 15; i++) { a->addr.v6.s6_addr[15-i] = sum % 256; sum >>= 8; } } return a; } if (strchr(s, ':')) a = cidr_parse6(s); else a = cidr_parse4(s); if (!a) return NULL; if (a->family != af_hint) { fprintf(stderr, "attempt to '%s' %s with %s address\n", op, (af_hint == AF_INET) ? "ipv4" : "ipv6", (af_hint != AF_INET) ? "ipv4" : "ipv6"); exit(4); } return a; } static bool cidr_howmany(struct cidr *a, struct cidr *b) { if (!quiet) { if (b->prefix < a->prefix) printf("0\n"); else printf("%u\n", 1 << (b->prefix - a->prefix)); } printed = true; return true; } static bool cidr_prefix(struct cidr *a, struct cidr *b) { a->prefix = b->prefix; return true; } static bool cidr_quiet(struct cidr *a) { quiet = true; return true; } struct op ops[] = { { .name = "add", .desc = "Add argument to base address", .f4.a2 = cidr_add4, .f6.a2 = cidr_add6 }, { .name = "sub", .desc = "Substract argument from base address", .f4.a2 = cidr_sub4, .f6.a2 = cidr_sub6 }, { .name = "network", .desc = "Turn base address into network address", .f4.a1 = cidr_network4, .f6.a1 = cidr_network6 }, { .name = "broadcast", .desc = "Turn base address into broadcast address", .f4.a1 = cidr_broadcast4 }, { .name = "prefix", .desc = "Set the prefix of base address to argument", .f4.a2 = cidr_prefix, .f6.a2 = cidr_prefix }, { .name = "netmask", .desc = "Print netmask of base address, does not change base address", .f4.a1 = cidr_netmask4 }, { .name = "howmany", .desc = "Print amount of righ-hand prefixes that fit into base address, " "does not change base address", .f4.a2 = cidr_howmany, .f6.a2 = cidr_howmany }, { .name = "contains", .desc = "Print '1' if argument fits into base address or '0' " "if not, does not change base address", .f4.a2 = cidr_contains4, .f6.a2 = cidr_contains6 }, { .name = "private", .desc = "Print '1' if base address is in RFC1918 private space or '0' " "if not, does not change base address", .f4.a1 = cidr_private4 }, { .name = "linklocal", .desc = "Print '1' if base address is in 169.254.0.0/16 or FE80::/10 " "link local space or '0' if not, does not change base address", .f4.a1 = cidr_linklocal4, .f6.a1 = cidr_linklocal6 }, { .name = "ula", .desc = "Print '1' if base address is in FC00::/7 unique local address " "(ULA) space or '0' if not, does not change base address", .f6.a1 = cidr_ula6 }, { .name = "quiet", .desc = "Suppress output, useful for test operation where the result can " "be inferred from the exit code, does not change base address", .f4.a1 = cidr_quiet, .f6.a1 = cidr_quiet }, { .name = "print", .desc = "Print intermediate result, invoked implicitely at the end of " "calculation if no intermediate prints happened", .f4.a1 = cidr_print4, .f6.a1 = cidr_print6 }, }; static void usage(const char *prog) { int i; fprintf(stderr, "\n" "Usage:\n\n" " %s {base address} operation [argument] " "[operation [argument] ...]\n\n" "Operations:\n\n", prog); for (i = 0; i < sizeof(ops) / sizeof(ops[0]); i++) { if (ops[i].f4.a2 || ops[i].f6.a2) { fprintf(stderr, " %s %s\n", ops[i].name, (ops[i].f4.a2 && ops[i].f6.a2) ? "{ipv4/ipv6/amount}" : (ops[i].f6.a2 ? "{ipv6/amount}" : "{ipv4/amount}")); } else { fprintf(stderr, " %s\n", ops[i].name); } fprintf(stderr, " %s.\n", ops[i].desc); if ((ops[i].f4.a1 && ops[i].f6.a1) || (ops[i].f4.a2 && ops[i].f6.a2)) fprintf(stderr, " Applicable to ipv4- and ipv6-addresses.\n\n"); else if (ops[i].f6.a2 || ops[i].f6.a1) fprintf(stderr, " Only applicable to ipv6-addresses.\n\n"); else fprintf(stderr, " Only applicable to ipv4-addresses.\n\n"); } fprintf(stderr, "Examples:\n\n" " Calculate a DHCP range:\n\n" " $ %s 192.168.1.1/255.255.255.0 network add 100 print add 150 print\n" " 192.168.1.100\n" " 192.168.1.250\n\n" " Count number of prefixes:\n\n" " $ %s 2001:0DB8:FDEF::/48 howmany ::/64\n" " 65536\n\n", prog, prog); exit(1); } static bool runop(struct cidr *a, char ***arg, int *status) { int i; char *arg1 = **arg; char *arg2 = *(*arg+1); struct cidr *b = NULL; if (!arg1) return false; for (i = 0; i < sizeof(ops) / sizeof(ops[0]); i++) { if (!strcmp(ops[i].name, arg1)) { if (ops[i].f4.a2 || ops[i].f6.a2) { if (!arg2) { fprintf(stderr, "'%s' requires an argument\n", ops[i].name); *status = 2; return false; } b = cidr_parse(ops[i].name, arg2, a->family); if (!b) { fprintf(stderr, "invalid address argument for '%s'\n", ops[i].name); *status = 3; return false; } *arg += 2; if (((a->family == AF_INET) && !ops[i].f4.a2) || ((a->family == AF_INET6) && !ops[i].f6.a2)) { fprintf(stderr, "'%s' not supported for %s addresses\n", ops[i].name, (a->family == AF_INET) ? "ipv4" : "ipv6"); *status = 5; return false; } *status = !((a->family == AF_INET) ? ops[i].f4.a2(a, b) : ops[i].f6.a2(a, b)); return true; } else { *arg += 1; if (((a->family == AF_INET) && !ops[i].f4.a1) || ((a->family == AF_INET6) && !ops[i].f6.a1)) { fprintf(stderr, "'%s' not supported for %s addresses\n", ops[i].name, (a->family == AF_INET) ? "ipv4" : "ipv6"); *status = 5; return false; } *status = !((a->family == AF_INET) ? ops[i].f4.a1(a) : ops[i].f6.a1(a)); return true; } } } return false; } int main(int argc, char **argv) { int status = 0; char **arg = argv+2; struct cidr *a; if (argc < 3) usage(argv[0]); a = strchr(argv[1], ':') ? cidr_parse6(argv[1]) : cidr_parse4(argv[1]); if (!a) usage(argv[0]); while (runop(a, &arg, &status)); if (*arg) { fprintf(stderr, "unknown operation '%s'\n", *arg); exit(6); } if (!printed && (status < 2)) { if (a->family == AF_INET) cidr_print4(a); else cidr_print6(a); } exit(status); }