/* * Copyright (C) 2012-2016 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library. If not, see * . */ #include #include #include #include #include #include #include #include #include #include "virrandom.h" #include "virthread.h" #include "virerror.h" #include "virfile.h" #include "virlog.h" #include "virstring.h" #define VIR_FROM_THIS VIR_FROM_NONE VIR_LOG_INIT("util.random"); /** * virRandomBits: * @nbits: Number of bits of randomness required * * Generate an evenly distributed random number between [0,2^nbits), where * @nbits must be in the range (0,64]. * * Return: a random number with @nbits entropy */ uint64_t virRandomBits(int nbits) { uint64_t ret = 0; if (virRandomBytes((unsigned char *) &ret, sizeof(ret)) < 0) { /* You're already hosed, so this particular non-random value * isn't any worse. */ return 0; } if (nbits < 64) ret &= (1ULL << nbits) - 1; return ret; } /** * virRandom: * * Generate an evenly distributed random number between [0.0,1.0) * * Return: a random number with 48 bits of entropy */ double virRandom(void) { uint64_t val = virRandomBits(48); return ldexp(val, -48); } /** * virRandomInt: * @max: upper limit * * Generate an evenly distributed random integer between [0, @max) * * Return: a random number between [0,@max) */ uint32_t virRandomInt(uint32_t max) { if (VIR_IS_POW2(max)) return virRandomBits(__builtin_ffs(max) - 1); return virRandom() * max; } /** * virRandomBytes * @buf: Pointer to location to store bytes * @buflen: Number of bytes to store * * Generate a stream of random bytes using gnutls_rnd() * into @buf of size @buflen * * Returns 0 on success or -1 (with error reported) */ int virRandomBytes(unsigned char *buf, size_t buflen) { int rv; if ((rv = gnutls_rnd(GNUTLS_RND_RANDOM, buf, buflen)) < 0) { virReportError(VIR_ERR_INTERNAL_ERROR, _("failed to generate byte stream: %s"), gnutls_strerror(rv)); return -1; } return 0; } #define QUMRANET_OUI "001a4a" #define VMWARE_OUI "000569" #define MICROSOFT_OUI "0050f2" #define XEN_OUI "00163e" int virRandomGenerateWWN(char **wwn, const char *virt_type) { const char *oui = NULL; if (!virt_type) { virReportError(VIR_ERR_INVALID_ARG, "%s", _("argument virt_type must not be NULL")); return -1; } if (STREQ(virt_type, "QEMU")) { oui = QUMRANET_OUI; } else if (STREQ(virt_type, "Xen") || STREQ(virt_type, "xenlight")) { oui = XEN_OUI; } else if (STREQ(virt_type, "ESX") || STREQ(virt_type, "VMWARE")) { oui = VMWARE_OUI; } else if (STREQ(virt_type, "HYPER-V")) { oui = MICROSOFT_OUI; } else { virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("Unsupported virt type")); return -1; } *wwn = g_strdup_printf("5" "%s%09llx", oui, (unsigned long long)virRandomBits(36)); return 0; }